125 results on '"Kyle L. Hoehn"'
Search Results
2. Targeting negative energy balance with calorie restriction and mitochondrial uncoupling in db/db mice
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Sing-Young Chen, Martina Beretta, Ellen M. Olzomer, Divya P. Shah, Derek Y.H. Wong, Stephanie J. Alexopoulos, Isabella Aleksovska, Joseph M. Salamoun, Christopher J. Garcia, Blake J. Cochran, Kerry-Anne Rye, Greg C. Smith, Frances L. Byrne, Margaret J. Morris, Webster L. Santos, James Cantley, and Kyle L. Hoehn
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Calorie restriction ,Mitochondrial uncoupling ,Obesity ,Diabetes ,Internal medicine ,RC31-1245 - Abstract
Objective: Calorie restriction is a first-line treatment for overweight individuals with metabolic impairments. However, few patients can adhere to long-term calorie restriction. An alternative approach to calorie restriction that also causes negative energy balance is mitochondrial uncoupling, which decreases the amount of energy that can be extracted from food. Herein we compare the metabolic effects of calorie restriction with the mitochondrial uncoupler BAM15 in the db/db mouse model of severe hyperglycemia, obesity, hypertriglyceridemia, and fatty liver. Methods: Male db/db mice were treated with ∼50% calorie restriction, BAM15 at two doses of 0.1% and 0.2% (w/w) admixed in diet, or 0.2% BAM15 with time-restricted feeding from 5 weeks of age. Mice were metabolically phenotyped over 4 weeks with assessment of key readouts including body weight, glucose tolerance, and liver steatosis. At termination, liver tissues were analysed by metabolomics and qPCR. Results: Calorie restriction and high-dose 0.2% BAM15 decreased body weight to a similar extent, but mice treated with BAM15 had far better improvement in glucose control. High-dose BAM15 treatment completely normalized fasting glucose and glucose tolerance to levels similar to lean db/+ control mice. Low-dose 0.1% BAM15 did not affect body mass but partially improved glucose tolerance to a similar degree as 50% calorie restriction. Both calorie restriction and high-dose BAM15 significantly improved hyperglucagonemia and liver and serum triglyceride levels. Combining high-dose BAM15 with time-restricted feeding to match the time that calorie restricted mice were fed resulted in the best metabolic phenotype most similar to lean db/+ controls. BAM15-mediated improvements in glucose control were associated with decreased glucagon levels and decreased expression of enzymes involved in hepatic gluconeogenesis. Conclusions: BAM15 and calorie restriction treatments improved most metabolic disease phenotypes in db/db mice. However, mice fed BAM15 had superior effects on glucose control compared to the calorie restricted group that consumed half as much food. Submaximal dosing with BAM15 demonstrated that its beneficial effects on glucose control are independent of weight loss. These data highlight the potential for mitochondrial uncoupler pharmacotherapies in the treatment of metabolic disease.
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- 2023
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3. Acetyl-CoA-carboxylase 1 (ACC1) plays a critical role in glucagon secretion
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Anna Veprik, Geoffrey Denwood, Dong Liu, Rula Bany Bakar, Valentin Morfin, Kara McHugh, Nchimunya N. Tebeka, Laurène Vetterli, Ekaterina Yonova-Doing, Fiona Gribble, Frank Reimann, Kyle L. Hoehn, Piers A. Hemsley, Jonas Ahnfelt-Rønne, Patrik Rorsman, Quan Zhang, Heidi de Wet, and James Cantley
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Biology (General) ,QH301-705.5 - Abstract
Veprik et al. show that Acetyl-CoA-carboxylase 1 (ACC1), an enzyme that couples glucose metabolism to lipogenesis, is involved in glucagon secretion and regulates S-acylation of critical glucose-sensing proteins. Loss of ACC1 in pancreatic alpha-cells negatively affects both size and number, as well as glucagon content, while in gut enteroendocrine cells leads to reduced release of glucagon-like peptide 1.
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- 2022
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4. Breast cancer growth and proliferation is suppressed by the mitochondrial targeted furazano[3,4-b]pyrazine BAM15
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Elizabeth R. M. Zunica, Christopher L. Axelrod, Eunhan Cho, Guillaume Spielmann, Gangarao Davuluri, Stephanie J. Alexopoulos, Martina Beretta, Kyle L. Hoehn, Wagner S. Dantas, Krisztian Stadler, William T. King, Kathryn Pergola, Brian A. Irving, Ingeborg M. Langohr, Shengping Yang, Charles L. Hoppel, L. Anne Gilmore, and John P. Kirwan
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BAM15 ,Breast cancer ,Tumor metabolism ,Mitochondrial function ,Cell proliferation ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Abstract Background Enhanced metabolic plasticity and diversification of energy production is a hallmark of highly proliferative breast cancers. This contributes to poor pharmacotherapy efficacy, recurrence, and metastases. We have previously identified a mitochondrial-targeted furazano[3,4-b]pyrazine named BAM15 that selectively reduces bioenergetic coupling efficiency and is orally available. Here, we evaluated the antineoplastic properties of uncoupling oxidative phosphorylation from ATP production in breast cancer using BAM15. Methods The anticancer effects of BAM15 were evaluated in human triple-negative MDA-MB-231 and murine luminal B, ERα-negative EO771 cells as well as in an orthotopic allograft model of highly proliferative mammary cancer in mice fed a standard or high fat diet (HFD). Untargeted transcriptomic profiling of MDA-MB-231 cells was conducted after 16-h exposure to BAM15. Additionally, oxidative phosphorylation and electron transfer capacity was determined in permeabilized cells and excised tumor homogenates after treatment with BAM15. Results BAM15 increased proton leak and over time, diminished cell proliferation, migration, and ATP production in both MDA-MB-231 and EO771 cells. Additionally, BAM15 decreased mitochondrial membrane potential, while inducing apoptosis and reactive oxygen species accumulation in MDA-MB-231 and EO771 cells. Untargeted transcriptomic profiling of MDA-MB-231 cells further revealed inhibition of signatures associated with cell survival and energy production by BAM15. In lean mice, BAM15 lowered body weight independent of food intake and slowed tumor progression compared to vehicle-treated controls. In HFD mice, BAM15 reduced tumor growth relative to vehicle and calorie-restricted weight-matched controls mediated in part by impaired cell proliferation, mitochondrial respiratory function, and ATP production. LC-MS/MS profiling of plasma and tissues from BAM15-treated animals revealed distribution of BAM15 in adipose, liver, and tumor tissue with low abundance in skeletal muscle. Conclusions Collectively, these data indicate that mitochondrial uncoupling may be an effective strategy to limit proliferation of aggressive forms of breast cancer. More broadly, these findings highlight the metabolic vulnerabilities of highly proliferative breast cancers which may be leveraged in overcoming poor responsiveness to existing therapies.
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- 2021
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5. Eosinophil function in adipose tissue is regulated by Krüppel-like factor 3 (KLF3)
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Alexander J. Knights, Emily J. Vohralik, Peter J. Houweling, Elizabeth S. Stout, Laura J. Norton, Stephanie J. Alexopoulos, Jinfen. J. Yik, Hanapi Mat Jusoh, Ellen M. Olzomer, Kim S. Bell-Anderson, Kathryn N. North, Kyle L. Hoehn, Merlin Crossley, and Kate G. R. Quinlan
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Science - Abstract
Immune cells are important regulators of adipose tissue function, including adaptive thermogenesis. Here the authors show that mice with Krüppel-like factor 3 (KLF3) deficiency in bone marrow-derived cells have increased adipose tissue beiging which may at least in part be due to altered eosinophil paracrine signaling.
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- 2020
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6. Mitochondrial uncoupler BAM15 reverses diet-induced obesity and insulin resistance in mice
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Stephanie J. Alexopoulos, Sing-Young Chen, Amanda E. Brandon, Joseph M. Salamoun, Frances L. Byrne, Christopher J. Garcia, Martina Beretta, Ellen M. Olzomer, Divya P. Shah, Ashleigh M. Philp, Stefan R. Hargett, Robert T. Lawrence, Brendan Lee, James Sligar, Pascal Carrive, Simon P. Tucker, Andrew Philp, Carolin Lackner, Nigel Turner, Gregory J. Cooney, Webster L. Santos, and Kyle L. Hoehn
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Science - Abstract
Obesity is a global pandemic with limited treatment options. Here, the authors show evidence in mice that the mitochondrial uncoupler BAM15 effectively induces fat loss without affecting food intake or compromising lean body mass.
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- 2020
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7. Proteomic pathways to metabolic disease and type 2 diabetes in the pancreatic islet
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Belinda Yau, Sheyda Naghiloo, Alexis Diaz-Vegas, Austin V. Carr, Julian Van Gerwen, Elise J. Needham, Dillon Jevon, Sing-Young Chen, Kyle L. Hoehn, Amanda E. Brandon, Laurence Macia, Gregory J. Cooney, Michael R. Shortreed, Lloyd M. Smith, Mark P. Keller, Peter Thorn, Mark Larance, David E. James, Sean J. Humphrey, and Melkam A. Kebede
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animal physiology ,diabetology ,proteomics ,Science - Abstract
Summary: Pancreatic islets are essential for maintaining physiological blood glucose levels, and declining islet function is a hallmark of type 2 diabetes. We employ mass spectrometry-based proteomics to systematically analyze islets from 9 genetic or diet-induced mouse models representing a broad cross-section of metabolic health. Quantifying the islet proteome to a depth of >11,500 proteins, this study represents the most detailed analysis of mouse islet proteins to date. Our data highlight that the majority of islet proteins are expressed in all strains and diets, but more than half of the proteins vary in expression levels, principally due to genetics. Associating these varied protein expression levels on an individual animal basis with individual phenotypic measures reveals islet mitochondrial function as a major positive indicator of metabolic health regardless of strain. This compendium of strain-specific and dietary changes to mouse islet proteomes represents a comprehensive resource for basic and translational islet cell biology.
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- 2021
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8. Mitochondrial Uncoupler BAM15 Ameliorates Associated Metabolic PCOS Traits in a Hyperandrogenic PCOS Mouse Model
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Valentina RODRIGUEZ PARIS, Stephanie J. ALEXOPOULOS, Ying HU, Divya P. SHAH, Ali AFLATOUNIAN, Melissa C. EDWARDS, Michael J. BERTOLDO, Robert B. GILCHRIST, Kyle L. HOEHN, and Kirsty A. WALTERS
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Reproduction ,QH471-489 - Abstract
Background: Polycystic ovary syndrome (PCOS) is a common endocrine condition characterized by endocrine, reproductive and metabolic abnormalities. There is no cure for PCOS and existing treatments are suboptimal. Obesity and adverse metabolic features are prevalent in PCOS patients, but weight loss has a beneficial effect on PCOS features. However, dietary interventions aimed at weight loss are difficult to sustain long-term. Interestingly, recent data from animal studies has shown that a mitochondrial uncoupler, BAM15, is an effective approach to pharmacologically treat obesity and metabolic diseases. Aim: To investigate the efficacy of BAM15 to ameliorate PCOS-traits in a PCOS mouse model. Method: The effect of BAM15 treatment on metabolic and reproductive PCOS features were evaluated in dihydrotestosterone (DHT)-induced PCOS mice fed a standard chow diet ± BAM15 for 10 weeks. Results: As expected, exposure of female mice to DHT induced the PCOS metabolic features of increased body weight (P
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- 2022
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9. Investigating the Expression and Function of the Glucose Transporter GLUT6 in Obesity
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Sing-Young Chen, Ellen M. Olzomer, Martina Beretta, James Cantley, Craig S. Nunemaker, Kyle L. Hoehn, and Frances L. Byrne
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obesity ,mouse model ,glucose transporter ,islet biology ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
Obesity-related insulin resistance is a highly prevalent and growing health concern, which places stress on the pancreatic islets of Langerhans by increasing insulin secretion to lower blood glucose levels. The glucose transporters GLUT1 and GLUT3 play a key role in glucose-stimulated insulin secretion in human islets, while GLUT2 is the key isoform in rodent islets. However, it is unclear whether other glucose transporters also contribute to insulin secretion by pancreatic islets. Herein, we show that SLC2A6 (GLUT6) is markedly upregulated in pancreatic islets from genetically obese leptin-mutant (ob/ob) and leptin receptor-mutant (db/db) mice, compared to lean controls. Furthermore, we observe that islet SLC2A6 expression positively correlates with body mass index in human patients with type 2 diabetes. To investigate whether GLUT6 plays a functional role in islets, we crossed GLUT6 knockout mice with C57BL/6 ob/ob mice. Pancreatic islets isolated from ob/ob mice lacking GLUT6 secreted more insulin in response to high-dose glucose, compared to ob/ob mice that were wild type for GLUT6. The loss of GLUT6 in ob/ob mice had no adverse impact on body mass, body composition, or glucose tolerance at a whole-body level. This study demonstrates that GLUT6 plays a role in pancreatic islet insulin secretion in vitro but is not a dominant glucose transporter that alters whole-body metabolic physiology in ob/ob mice.
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- 2022
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10. Delivering bioactive cyclic peptides that target Hsp90 as prodrugs
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Yuantao Huo, Laura K. Buckton, Jack L. Bennett, Eloise C. Smith, Frances L. Byrne, Kyle L. Hoehn, Marwa N. Rahimi, and Shelli R. McAlpine
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peptide drug delivery ,protein-protein interactions ,prodrugs ,heat shock protein 90 ,cell permeability ,Therapeutics. Pharmacology ,RM1-950 - Abstract
The most challenging issue facing peptide drug development is producing a molecule with optimal physical properties while maintaining target binding affinity. Masking peptides with protecting groups that can be removed inside the cell, produces a cell-permeable peptide, which theoretically can maintain its biological activity. Described are series of prodrugs masked using: (a) O-alkyl, (b) N-alkyl, and (c) acetyl groups, and their binding affinity for Hsp90. Alkyl moieties increased compound permeability, Papp, from 3.3 to 5.6, however alkyls could not be removed by liver microsomes or in-vivo and their presence decreased target binding affinity (IC50 of ≥10 µM). Thus, unlike small molecules, peptide masking groups cannot be predictably removed; their removal is related to the 3-D conformation. O-acetyl groups were cleaved but are labile, increasing challenges during synthesis. Utilising acetyl groups coupled with mono-methylated amines may decrease the polarity of a peptide, while maintaining binding affinity.
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- 2019
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11. Differences in the Active Endometrial Microbiota across Body Weight and Cancer in Humans and Mice
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Nadeem O. Kaakoush, Ellen M. Olzomer, Melidya Kosasih, Amy R. Martin, Farokh Fargah, Neil Lambie, Daniella Susic, Kyle L. Hoehn, Rhonda Farrell, and Frances L. Byrne
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uterine cancer ,microbiota ,lactobacillus ,obesity ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Obesity is a risk factor for endometrial cancer. The aim of this study was to determine whether actively replicating microbiota in the endometrium differ between obese vs. lean and cancer vs. benign states. We performed 16S rRNA amplicon sequencing on endometrial tissues from lean and obese women with and without endometrial cancer, and lean and obese mice. Results displayed human endometrial microbiota clustered into three community types (R = 0.363, p = 0.001). Lactobacillus was dominant in community type 1 (C1) while community type 2 (C2) had high levels of Proteobacteria and more cancer samples when compared to C1 (p = 0.007) and C3 (p = 0.0002). A significant increase in the prevalence of the C2 community type was observed across body mass index and cancer (χ2 = 14.24, p = 0.0002). The relative abundance of Lactobacillus was lower in cancer samples (p = 0.0043), and an OTU with 100% similarity to Lactobacillus iners was enriched in control samples (p = 0.0029). Mouse endometrial microbiota also clustered into three community types (R = 0.419, p = 0.001) which were not influenced by obesity. In conclusion, obesity and cancer are associated with community type prevalence in the human endometrium, and Lactobacillus abundance is associated with normal uterine histologies in humans and mice.
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- 2022
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12. Update on Glycosphingolipids Abundance in Hepatocellular Carcinoma
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Frances L. Byrne, Ellen M. Olzomer, Nina Lolies, Kyle L. Hoehn, and Marthe-Susanna Wegner
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glycolysis ,GEMs ,oxidative phosphorylation ,UGCG ,glucosylceramide ,normal liver cells ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
Hepatocellular carcinoma (HCC) is the most frequent type of primary liver cancer. Low numbers of HCC patients being suitable for liver resection or transplantation and multidrug resistance development during pharmacotherapy leads to high death rates for HCC patients. Understanding the molecular mechanisms of HCC etiology may contribute to the development of novel therapeutic strategies for prevention and treatment of HCC. UDP-glucose ceramide glycosyltransferase (UGCG), a key enzyme in glycosphingolipid metabolism, generates glucosylceramide (GlcCer), which is the precursor for all glycosphingolipids (GSLs). Since UGCG gene expression is altered in 0.8% of HCC tumors, GSLs may play a role in cellular processes in liver cancer cells. Here, we discuss the current literature about GSLs and their abundance in normal liver cells, Gaucher disease and HCC. Furthermore, we review the involvement of UGCG/GlcCer in multidrug resistance development, globosides as a potential prognostic marker for HCC, gangliosides as a potential liver cancer stem cell marker, and the role of sulfatides in tumor metastasis. Only a limited number of molecular mechanisms executed by GSLs in HCC are known, which we summarize here briefly. Overall, the role GSLs play in HCC progression and their ability to serve as biomarkers or prognostic indicators for HCC, requires further investigation.
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- 2022
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13. Phenotypic screen for oxygen consumption rate identifies an anti-cancer naphthoquinone that induces mitochondrial oxidative stress
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Frances L. Byrne, Ellen M. Olzomer, Gabriella R. Marriott, Lake-Ee Quek, Alice Katen, Jacky Su, Marin E. Nelson, Gene Hart-Smith, Mark Larance, Veronica F. Sebesfi, Jeff Cuff, Gabriella E. Martyn, Elizabeth Childress, Stephanie J. Alexopoulos, Ivan K. Poon, Maree C. Faux, Antony W. Burgess, Glen Reid, Joshua A. McCarroll, Webster L. Santos, Kate GR. Quinlan, Nigel Turner, Daniel J. Fazakerley, Naresh Kumar, and Kyle L. Hoehn
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Medicine (General) ,R5-920 ,Biology (General) ,QH301-705.5 - Abstract
A hallmark of cancer cells is their ability to reprogram nutrient metabolism. Thus, disruption to this phenotype is a potential avenue for anti-cancer therapy. Herein we used a phenotypic chemical library screening approach to identify molecules that disrupted nutrient metabolism (by increasing cellular oxygen consumption rate) and were toxic to cancer cells. From this screen we discovered a 1,4-Naphthoquinone (referred to as BH10) that is toxic to a broad range of cancer cell types. BH10 has improved cancer-selective toxicity compared to doxorubicin, 17-AAG, vitamin K3, and other known anti-cancer quinones. BH10 increases glucose oxidation via both mitochondrial and pentose phosphate pathways, decreases glycolysis, lowers GSH:GSSG and NAPDH/NAPD+ ratios exclusively in cancer cells, and induces necrosis. BH10 targets mitochondrial redox defence as evidenced by increased mitochondrial peroxiredoxin 3 oxidation and decreased mitochondrial aconitase activity, without changes in markers of cytosolic or nuclear damage. Over-expression of mitochondria-targeted catalase protects cells from BH10-mediated toxicity, while the thioredoxin reductase inhibitor auranofin synergistically enhances BH10-induced peroxiredoxin 3 oxidation and cytotoxicity. Overall, BH10 represents a 1,4-Naphthoquinone with an improved cancer-selective cytotoxicity profile via its mitochondrial specificity. Keywords: Cancer metabolism, Quinone, Peroxiredoxin, Mitochondria
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- 2020
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14. A selective inhibitor of ceramide synthase 1 reveals a novel role in fat metabolism
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Nigel Turner, Xin Ying Lim, Hamish D. Toop, Brenna Osborne, Amanda E. Brandon, Elysha N. Taylor, Corrine E. Fiveash, Hemna Govindaraju, Jonathan D. Teo, Holly P. McEwen, Timothy A. Couttas, Stephen M. Butler, Abhirup Das, Greg M. Kowalski, Clinton R. Bruce, Kyle L. Hoehn, Thomas Fath, Carsten Schmitz-Peiffer, Gregory J. Cooney, Magdalene K. Montgomery, Jonathan C. Morris, and Anthony S. Don
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Science - Abstract
Ceramides are signalling molecules that regulate several physiological functions including insulin sensitivity. Here the authors report a selective ceramide synthase 1 inhibitor that counteracts lipid accumulation within the muscle and adiposity by increasing fatty acid oxidation but without affecting insulin sensitivity in mice fed with an obesogenic diet.
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- 2018
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15. Dynamic Metabolomics Reveals that Insulin Primes the Adipocyte for Glucose Metabolism
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James R. Krycer, Katsuyuki Yugi, Akiyoshi Hirayama, Daniel J. Fazakerley, Lake-Ee Quek, Richard Scalzo, Satoshi Ohno, Mark P. Hodson, Satsuki Ikeda, Futaba Shoji, Kumi Suzuki, Westa Domanova, Benjamin L. Parker, Marin E. Nelson, Sean J. Humphrey, Nigel Turner, Kyle L. Hoehn, Gregory J. Cooney, Tomoyoshi Soga, Shinya Kuroda, and David E. James
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Biology (General) ,QH301-705.5 - Abstract
Summary: Insulin triggers an extensive signaling cascade to coordinate adipocyte glucose metabolism. It is considered that the major role of insulin is to provide anabolic substrates by activating GLUT4-dependent glucose uptake. However, insulin stimulates phosphorylation of many metabolic proteins. To examine the implications of this on glucose metabolism, we performed dynamic tracer metabolomics in cultured adipocytes treated with insulin. Temporal analysis of metabolite concentrations and tracer labeling revealed rapid and distinct changes in glucose metabolism, favoring specific glycolytic branch points and pyruvate anaplerosis. Integrating dynamic metabolomics and phosphoproteomics data revealed that insulin-dependent phosphorylation of anabolic enzymes occurred prior to substrate accumulation. Indeed, glycogen synthesis was activated independently of glucose supply. We refer to this phenomenon as metabolic priming, whereby insulin signaling creates a demand-driven system to “pull” glucose into specific anabolic pathways. This complements the supply-driven regulation of anabolism by substrate accumulation and highlights an additional role for insulin action in adipocyte glucose metabolism. : Krycer et al. explore how insulin regulates adipocyte metabolism. It is widely held that energy storage (anabolism) occurs as a substrate accumulates. However, using dynamic tracer metabolomics and overlaying phosphoproteomics data, they find that insulin signaling triggers anabolism before substrates accumulate, creating a “demand-driven” system to prime adipocytes for glucose metabolism. Keywords: adipocyte, insulin, glucose, metabolomics, metabolic tracer, metabolic priming
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- 2017
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16. Inhibition of hepatic lipogenesis enhances liver tumorigenesis by increasing antioxidant defence and promoting cell survival
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Marin E. Nelson, Sujoy Lahiri, Jenny D. Y. Chow, Frances L. Byrne, Stefan R. Hargett, David S. Breen, Ellen M. Olzomer, Lindsay E. Wu, Gregory J. Cooney, Nigel Turner, David E. James, Jill K. Slack-Davis, Carolin Lackner, Stephen H. Caldwell, and Kyle L. Hoehn
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Science - Abstract
The lipogenic pathway is often upregulated in liver tumours and regarded as a therapeutic target. Here, the authors show instead that blocking lipogenesis via knockout of acetyl-CoA carboxylase genes results in increased susceptibility to liver tumorigenesis associated with an increased antioxidant defence.
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- 2017
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17. Lysophosphatidic acid counteracts glucagon-induced hepatocyte glucose production via STAT3
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Evan P. Taddeo, Stefan R. Hargett, Sujoy Lahiri, Marin E. Nelson, Jason A. Liao, Chien Li, Jill K. Slack-Davis, Jose L. Tomsig, Kevin R. Lynch, Zhen Yan, Thurl E. Harris, and Kyle L. Hoehn
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Medicine ,Science - Abstract
Abstract Hepatic glucose production (HGP) is required to maintain normoglycemia during fasting. Glucagon is the primary hormone responsible for increasing HGP; however, there are many additional hormone and metabolic factors that influence glucagon sensitivity. In this study we report that the bioactive lipid lysophosphatidic acid (LPA) regulates hepatocyte glucose production by antagonizing glucagon-induced expression of the gluconeogenic enzyme phosphoenolpyruvate carboxykinase (PEPCK). Treatment of primary hepatocytes with exogenous LPA blunted glucagon-induced PEPCK expression and glucose production. Similarly, knockout mice lacking the LPA-degrading enzyme phospholipid phosphate phosphatase type 1 (PLPP1) had a 2-fold increase in endogenous LPA levels, reduced PEPCK levels during fasting, and decreased hepatic gluconeogenesis in response to a pyruvate challenge. Mechanistically, LPA antagonized glucagon-mediated inhibition of STAT3, a transcriptional repressor of PEPCK. Importantly, LPA did not blunt glucagon-stimulated glucose production or PEPCK expression in hepatocytes lacking STAT3. These data identify a novel role for PLPP1 activity and hepatocyte LPA levels in glucagon sensitivity via a mechanism involving STAT3.
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- 2017
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18. Serial MRI Imaging Reveals Minimal Impact of Ketogenic Diet on Established Liver Tumor Growth
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Frances L. Byrne, Stefan R. Hargett, Sujoy Lahiri, R. Jack Roy, Stuart S. Berr, Stephen H. Caldwell, and Kyle L. Hoehn
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liver cancer ,ketosis ,diethylnitrosamine ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Rodent models of liver tumorigenesis have reproducibly shown that dietary sugar intake is a powerful driver of liver tumor initiation and growth. In contrast, dietary sugar restriction with ketogenic diets or calorie restriction generally prevents liver tumor formation. Ketogenic diet is viewed positively as a therapeutic adjuvant; however, most ketogenic diet studies described to date have been performed in prevention mode rather than treatment mode. Therefore, it remains unclear whether a ketogenic diet can be administered in late stages of disease to stall or reverse liver tumor growth. To model the clinically relevant treatment mode, we administered a ketogenic diet to mice after liver tumor initiation and monitored tumor growth by magnetic resonance imaging (MRI). Male C57BL/6 mice were injected with diethylnitrosamine (DEN) at 2 weeks of age and fed a chow diet until 39 weeks of age, when they underwent MRI imaging to detect liver tumors. Mice were then randomised into two groups and fed either a chow diet or switched to a ketogenic diet from 40–48 weeks of age. Serial MRIs were performed at 44 and 48 weeks of age. All mice had tumors at study completion and there were no differences in total tumor burden between diet groups. Although a ketogenic diet has marked protective effects against DEN-induced liver tumourigenesis in this mouse model, these data demonstrate that ketogenic diet cannot stop the progression of established liver tumors.
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- 2018
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19. Oxadiazolopyridine Derivatives as Efficacious Mitochondrial Uncouplers in the Prevention of Diet-Induced Obesity
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Jacob H. Murray, Ariel L. Burgio, Martina Beretta, Stefan R. Hargett, Thurl E. Harris, Ellen Olzomer, R. Justin Grams, Christopher J. Garcia, Catherine Li, Joseph M. Salamoun, Kyle L. Hoehn, and Webster L. Santos
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Drug Discovery ,Molecular Medicine - Published
- 2023
20. Supplemental Figures S1-8 from Metabolic Vulnerabilities in Endometrial Cancer
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Kyle L. Hoehn, Jill K. Slack-Davis, Kodi S. Ravichandran, Kelle H. Moley, Douglas C. Marchion, Johnathan M. Lancaster, Kristen A. Atkins, William D. Baker, Marin E. Healy, Jenny D.Y. Chow, Jose L. Tomsig, Susan C. Modesitt, Ivan K.H. Poon, and Frances L. Byrne
- Abstract
Supplemental Figures S1-8. Figure S1: Protein expression in human endometrial tissue. Figure S2: GLUT6 expression in human endometrial tissue Figure S3: Correlation between metabolic protein expression and metabolism in endometrial cells. Figure S4: GLUT6 knockdown in endometrial cancer cells induces cell death. Figure S5: Correlation analyses for drug sensitivity. Figure S6: Precursor Ion Scan of Pyruvylated-CoA. Figure S7: Antioxidants (without thiol groups) could not protect against 3-bromopyruvate-mediated cell death. Figure S8: ATP levels and cell death induced by 3-bromopyruvate.
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- 2023
21. Supplemental Methods from Metabolic Vulnerabilities in Endometrial Cancer
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Kyle L. Hoehn, Jill K. Slack-Davis, Kodi S. Ravichandran, Kelle H. Moley, Douglas C. Marchion, Johnathan M. Lancaster, Kristen A. Atkins, William D. Baker, Marin E. Healy, Jenny D.Y. Chow, Jose L. Tomsig, Susan C. Modesitt, Ivan K.H. Poon, and Frances L. Byrne
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Supplemental Methods. Includes more detailed methods for the main manuscript and additional supplemental methods including Cell Culture, Sources of drugs/radioactive tracers,Targets/functions of metabolic drugs and antioxidants, Preparation of protein lysates, Nutrient metabolism assays, qPCR primer sequences, Cytotoxicity assays, Cell doubling times, Cellular ATP levels, ROS assays, Mass spectrometry of Acetyl-CoA and Pyruvylated-CoA, and Supplemental References.
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- 2023
22. Macrophage acetyl-CoA carboxylase regulates acute inflammation through control of glucose and lipid metabolism
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Scott Yeudall, Clint M. Upchurch, Philip V. Seegren, Caitlin M. Pavelec, Jan Greulich, Michael C. Lemke, Thurl E. Harris, Bimal N. Desai, Kyle L. Hoehn, and Norbert Leitinger
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Lipopolysaccharides ,Mice, Knockout ,Inflammation ,Mice ,Glucose ,Multidisciplinary ,Macrophages ,Animals ,Lipid Metabolism ,Acetyl-CoA Carboxylase - Abstract
Acetyl-CoA carboxylase (ACC) regulates lipid synthesis; however, its role in inflammatory regulation in macrophages remains unclear. We generated mice that are deficient in both ACC isoforms in myeloid cells. ACC deficiency altered the lipidomic, transcriptomic, and bioenergetic profile of bone marrow–derived macrophages, resulting in a blunted response to proinflammatory stimulation. In response to lipopolysaccharide (LPS), ACC is required for the early metabolic switch to glycolysis and remodeling of the macrophage lipidome. ACC deficiency also resulted in impaired macrophage innate immune functions, including bacterial clearance. Myeloid-specific deletion or pharmacological inhibition of ACC in mice attenuated LPS-induced expression of proinflammatory cytokines interleukin-6 (IL-6) and IL-1β, while pharmacological inhibition of ACC increased susceptibility to bacterial peritonitis in wild-type mice. Together, we identify a critical role for ACC in metabolic regulation of the innate immune response in macrophages, and thus a clinically relevant, unexpected consequence of pharmacological ACC inhibition.
- Published
- 2022
23. Conversion of oxadiazolo[3,4-b]pyrazines to imidazo[4,5-b]pyrazines via a tandem reduction-cyclization sequence generates new mitochondrial uncouplers
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Yumin Dai, José A. Santiago-Rivera, Stefan Hargett, Joseph M. Salamoun, Kyle L. Hoehn, and Webster L. Santos
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Oxadiazoles ,Cyclization ,Pyrazines ,Organic Chemistry ,Clinical Biochemistry ,Drug Discovery ,Pharmaceutical Science ,Molecular Medicine ,Molecular Biology ,Biochemistry ,Mitochondria - Abstract
We report new mitochondrial uncouplers derived from the conversion of [1,2,5]oxadiazolo[3,4-b]pyrazines to 1H-imidazo[4,5-b]pyrazines. The in situ Fe-mediated reduction of the oxadiazole fragment followed by cyclization gave access to imidazopyrazines in moderate to good yields. A selection of orthoesters also allowed functionalization on the 2-position of the imidazole ring. This method afforded a variety of imidazopyrazine derivatives with varying substitution on the 2, 5 and 6 positions. Our studies suggest that both a 2-trifluoromethyl group and N-methylation are crucial for mitochondrial uncoupling capacity.
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- 2022
24. In vitro coronal protein signatures and biological impact of silver nanoparticles synthesized with different natural polymers as capping agents
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Alexander H. Soeriyadi, Kyle L. Hoehn, Priyanka Srivastava, Cindy Gunawan, Rose Amal, and Christopher P. Marquis
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food.ingredient ,Chemistry ,General Engineering ,Nanoparticle ,Bioengineering ,Protein Corona ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Haemolysis ,01 natural sciences ,Gelatin ,Atomic and Molecular Physics, and Optics ,Silver nanoparticle ,0104 chemical sciences ,Particle aggregation ,food ,In vivo ,Particle ,General Materials Science ,0210 nano-technology ,Nuclear chemistry - Abstract
Biopolymer-capped particles, sodium alginate-, gelatin- and reconstituted silk fibroin-capped nanosilver (AgNPs), were synthesized with an intention to study, simultaneously, their in vitro and in vivo haemocompatibility, one of the major safety factors in biomedical applications. Solid state characterization showed formation of spherical nanoparticles with 5 to 30 nm primary sizes (transmission electron microscopy) and X-ray photoelectron spectroscopy analysis of particles confirmed silver bonding with the biopolymer moieties. The degree of aggregation of the biopolymer-capped AgNPs in the synthesis medium (ultrapure water) is relatively low, with comparable hydrodynamic size with those of the control citrate-stabilized NPs, and remained relatively unchanged even after 6 weeks. The polymer-capped nanoparticles showed different degrees of aggregation in biologically relevant media – PBS (pH 7.4) and 2% human blood plasma – with citrate- (control) and alginate-capped particles showing the highest aggregation, while gelatin- and silk fibroin-capped particles revealed better stability and less aggregation in these media. In vitro cytotoxicity studies revealed that the polymer-capped particles exhibited both concentration and (hydrodynamic) size-dependent haemolytic activity, the extent of which was higher (up to 100% in some cases) in collected whole blood samples of healthy human volunteers when compared to that in the washed erythrocytes. This difference is thought to result from the detected protein corona formation on the nanoparticle surface in the whole blood system, which was associated with reduced particle aggregation, causing more severe cytotoxic effects. At the tested particle concentration range in vitro, we observed a negligible haemolysis effect in vivo (Balb/c mice). Polymer-capped particles did accumulate in organs, with the highest levels detected in the liver (up to 422 μg per g tissue), yet no adverse behavioural effects were observed in the mice during the duration of the nanoparticle exposure.
- Published
- 2021
25. Investigation of circular RNA transcriptome in obesity-related endometrial cancer
- Author
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Konii, Takenaka, Ellen M, Olzomer, Kyle L, Hoehn, Ashton, Curry-Hyde, Bei, Jun Chen, Rhonda, Farrell, Frances L, Byrne, and Michael, Janitz
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Genetics ,General Medicine - Abstract
The present study has investigated the circular RNA (circRNA) transcriptome of twenty obese and postmenopausal women, recruited in Australia, with endometrial cancer (EC). This paper expands on previous findings which evaluated the circRNA transcriptome of a similar cohort of six women recruited in the United States of America. EC is the most common gynaecological malignancy and the fifth most common cancer in women worldwide with obesity as one of its major risk factors. CircRNAs, a class of non-coding RNAs, are involved in many human diseases including cancer. As such the objective of this study was to investigate the circRNA transcriptome of these twenty women and identify circRNAs of interest. We obtained paired samples (EC and adjacent normal tissue) from the cohort of twenty women. Samples were subjected to ribosomal RNA depletion and sequencing performed using Illumina sequencing technology. CircRNAs were identified through CIRI2 and CIRCexplorer2 and common circRNAs extracted for differential expression with edgeR which met the criteria of counts per million0.1 and expressed in ≥ 10 . We found that the overall abundance of circRNAs was lower in EC compared to adjacent non-cancerous endometrial tissue. We also identified hotspot genes, genes expressing over 10 distinct circRNA isoforms. There were 82 hotspot genes in normal tissue and 23 hotspot genes in EC. There were 174 significantly differentially expressed circRNAs, of which 172 were down-regulated and 2 were up-regulated in EC. The circRNAs identified from this study may act as diagnostic or prognostic biomarkers for EC in obese women. While the circRNA transcriptome of obesity-related EC has been investigated further work is required to determine their functional significance.
- Published
- 2023
26. Transient Intermittent Hyperglycemia Accelerates Atherosclerosis by Promoting Myelopoiesis
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Raelene Pickering, Man K.S. Lee, Kyle L. Hoehn, Graeme I. Lancaster, Josephine M. Forbes, Michelle C Flynn, Ira J. Goldberg, Fiona Hortle, Ellen M. Olzomer, Tessa J. Barrett, Dragana Dragoljevic, Assam El-Osta, Domenica A. McCarthy, Merlin C. Thomas, Andrew J. Murphy, Frances L. Byrne, Edward A. Fisher, Liza Makowski, Nordin M J Hanssen, Annas Al-Sharea, Casper G. Schalkwijk, Helene L. Kammoun, Michael J Kraakman, Prabhakara R Nagareddy, Christos Tikellis, Mark E. Cooper, Interne Geneeskunde, RS: Carim - V01 Vascular complications of diabetes and metabolic syndrome, Vascular Medicine, ACS - Diabetes & metabolism, ACS - Atherosclerosis & ischemic syndromes, and Amsterdam Gastroenterology Endocrinology Metabolism
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Blood Glucose ,Male ,0301 basic medicine ,Mice, Knockout, ApoE ,Neutrophils ,Physiology ,Glucose uptake ,Receptor for Advanced Glycation End Products ,030204 cardiovascular system & hematology ,INSULIN-INDUCED HYPOGLYCEMIA ,Monocytes ,DISEASE ,GLUCOSE ,0302 clinical medicine ,Glycation ,BINDING ,Prediabetes ,MACROPHAGES ,Myelopoiesis ,Glucose Transporter Type 1 ,Plaque, Atherosclerotic ,diabetes mellitus ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,Glycolysis ,Signal Transduction ,medicine.medical_specialty ,Inflammation ,Diet, High-Fat ,Article ,03 medical and health sciences ,stem cells ,Diabetes mellitus ,Internal medicine ,medicine ,Animals ,Calgranulin B ,Humans ,Calgranulin A ,EATING PATTERNS ,RECEPTOR ,business.industry ,MONOCYTOSIS ,Glucose transporter ,DIABETES-MELLITUS ,medicine.disease ,Mice, Inbred C57BL ,Disease Models, Animal ,030104 developmental biology ,Endocrinology ,HEMATOPOIETIC STEM ,inflammation ,Hyperglycemia ,Transient (oscillation) ,atherosclerosis ,business ,metabolism ,Biomarkers - Abstract
Rationale: Treatment efficacy for diabetes mellitus is largely determined by assessment of HbA1c (glycated hemoglobin A1c) levels, which poorly reflects direct glucose variation. People with prediabetes and diabetes mellitus spend >50% of their time outside the optimal glucose range. These glucose variations, termed transient intermittent hyperglycemia (TIH), appear to be an independent risk factor for cardiovascular disease, but the pathological basis for this association is unclear. Objective: To determine whether TIH per se promotes myelopoiesis to produce more monocytes and consequently adversely affects atherosclerosis. Methods and Results: To create a mouse model of TIH, we administered 4 bolus doses of glucose at 2-hour intervals intraperitoneally once to WT (wild type) or once weekly to atherosclerotic prone mice. TIH accelerated atherogenesis without an increase in plasma cholesterol, seen in traditional models of diabetes mellitus. TIH promoted myelopoiesis in the bone marrow, resulting in increased circulating monocytes, particularly the inflammatory Ly6-C hi subset, and neutrophils. Hematopoietic-restricted deletion of S100a9 , S100a8 , or its cognate receptor Rage prevented monocytosis. Mechanistically, glucose uptake via GLUT (glucose transporter)-1 and enhanced glycolysis in neutrophils promoted the production of S100A8/A9. Myeloid-restricted deletion of Slc2a1 (GLUT-1) or pharmacological inhibition of S100A8/A9 reduced TIH-induced myelopoiesis and atherosclerosis. Conclusions: Together, these data provide a mechanism as to how TIH, prevalent in people with impaired glucose metabolism, contributes to cardiovascular disease. These findings provide a rationale for continual glucose control in these patients and may also suggest that strategies aimed at targeting the S100A8/A9-RAGE (receptor for advanced glycation end products) axis could represent a viable approach to protect the vulnerable blood vessels in diabetes mellitus. Graphic Abstract: A graphic abstract is available for this article.
- Published
- 2020
27. 6-Amino[1,2,5]oxadiazolo[3,4-b]pyrazin-5-ol Derivatives as Efficacious Mitochondrial Uncouplers in STAM Mouse Model of Nonalcoholic Steatohepatitis
- Author
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Joseph M. Salamoun, Stefan R. Hargett, Martina Beretta, Stephanie J. Alexopoulos, Ellen M. Olzomer, Divya P. Shah, Murray Jacob H, Webster L. Santos, Sing-Young Chen, Christopher J Garcia, Simon P. Tucker, and Kyle L. Hoehn
- Subjects
0303 health sciences ,Chemistry ,Transporter ,Pharmacology ,medicine.disease ,01 natural sciences ,Small molecule ,In vitro ,0104 chemical sciences ,Bioavailability ,010404 medicinal & biomolecular chemistry ,03 medical and health sciences ,Fibrosis ,Drug Discovery ,medicine ,Molecular Medicine ,Myocyte ,Inner mitochondrial membrane ,030304 developmental biology ,EC50 - Abstract
Small molecule mitochondrial uncouplers have recently garnered great interest for their potential in treating nonalcoholic steatohepatitis (NASH). In this study, we report the structure-activity relationship profiling of a 6-amino[1,2,5]oxadiazolo[3,4-b]pyrazin-5-ol core, which utilizes the hydroxy moiety as the proton transporter across the mitochondrial inner membrane. We demonstrate that a wide array of substituents is tolerated with this novel scaffold that increased cellular metabolic rates in vitro using changes in oxygen consumption rate as a readout. In particular, compound SHS4121705 (12i) displayed an EC50 of 4.3 μM in L6 myoblast cells and excellent oral bioavailability and liver exposure in mice. In the STAM mouse model of NASH, administration of 12i at 25 mg kg-1 day-1 lowered liver triglyceride levels and improved liver markers such as alanine aminotransferase, NAFLD activity score, and fibrosis. Importantly, no changes in body temperature or food intake were observed. As potential treatment of NASH, mitochondrial uncouplers show promise for future development.
- Published
- 2020
28. UGCG overexpression leads to increased glycolysis and increased oxidative phosphorylation of breast cancer cells
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Marthe-Susanna Wegner, Lisa Gruber, Nina Schömel, Ellen M. Olzomer, Kyle L. Hoehn, Stephanie J. Alexopoulos, Nerea Ferreirós, Robert Gurke, Gerd Geisslinger, Frances L. Byrne, Sandra Trautmann, and Dominique Thomas
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Mitochondrial Turnover ,Glycobiology ,lcsh:Medicine ,Breast Neoplasms ,Oxidative phosphorylation ,Mitochondrion ,medicine.disease_cause ,Endoplasmic Reticulum ,Article ,Oxidative Phosphorylation ,Breast cancer ,medicine ,Humans ,Glycolysis ,lcsh:Science ,Multidisciplinary ,Chemistry ,lcsh:R ,Sphingolipid ,Cancer metabolism ,Cell biology ,Mitochondria ,Glutamine ,Gene Expression Regulation, Neoplastic ,Metabolic pathway ,Glucosyltransferases ,MCF-7 Cells ,lcsh:Q ,Energy Metabolism ,Oxidative stress - Abstract
The only enzyme in the glycosphingolipid (GSL) metabolic pathway, which produces glucosylceramide (GlcCer) de novo is UDP-glucose ceramide glucosyltransferase (UGCG). UGCG is linked to pro-cancerous processes such as multidrug resistance development and increased proliferation in several cancer types. Previously, we showed an UGCG-dependent glutamine metabolism adaption to nutrient-poor environment of breast cancer cells. This adaption includes reinforced oxidative stress response and fueling the tricarboxylic acid (TCA) cycle by increased glutamine oxidation. In the current study, we investigated glycolytic and oxidative metabolic phenotypes following UGCG overexpression (OE). UGCG overexpressing MCF-7 cells underwent a metabolic shift from quiescent/aerobic to energetic metabolism by increasing both glycolysis and oxidative glucose metabolism. The energetic metabolic phenotype was not associated with increased mitochondrial mass, however, markers of mitochondrial turnover were increased. UGCG OE altered sphingolipid composition of the endoplasmic reticulum (ER)/mitochondria fractions that may contribute to increased mitochondrial turnover and increased cell metabolism. Our data indicate that GSL are closely connected to cell energy metabolism and this finding might contribute to development of novel therapeutic strategies for cancer treatment.
- Published
- 2020
29. [1,2,5]Oxadiazolo[3,4-b]pyrazine-5,6-diamine Derivatives as Mitochondrial Uncouplers for the Potential Treatment of Nonalcoholic Steatohepatitis
- Author
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Stefan R. Hargett, Elizabeth S. Childress, Joseph M. Salamoun, Jose A Santiago-Rivera, Divya P. Shah, Christopher J Garcia, Webster L. Santos, Sing-Young Chen, Kyle L. Hoehn, Stephanie J. Alexopoulos, Yumin Dai, and Simon P. Tucker
- Subjects
Male ,Pyrazine ,Protonophore ,Mitochondria, Liver ,Diamines ,Mitochondrion ,01 natural sciences ,Article ,03 medical and health sciences ,chemistry.chemical_compound ,Oxygen Consumption ,Aniline ,Non-alcoholic Fatty Liver Disease ,In vivo ,Drug Discovery ,Animals ,030304 developmental biology ,Oxadiazoles ,0303 health sciences ,Uncoupling Agents ,Depolarization ,Small molecule ,0104 chemical sciences ,Mice, Inbred C57BL ,010404 medicinal & biomolecular chemistry ,Liver ,chemistry ,Biochemistry ,Pyrazines ,Molecular Medicine ,Lead compound - Abstract
Small molecule mitochondrial uncouplers are emerging as a new class of molecules for the treatment of nonalcoholic steatohepatitis. We utilized BAM15, a potent protonophore that uncouples the mitochondria without depolarizing the plasma membrane, as a lead compound for structure-activity profiling. Using oxygen consumption rate as an assay for determining uncoupling activity, changes on the 5- and 6-position of the oxadiazolopyrazine core were introduced. Our studies suggest that unsymmetrical aniline derivatives bearing electron withdrawing groups are preferred compared to the symmetrical counterparts. In addition, alkyl substituents are not tolerated, and the N-H proton of the aniline ring is responsible for the protonophore activity. In particular, compound 10b had an EC(50) value of 190 nM in L6 myoblast cells. In an in vivo model of NASH, 10b decreased liver triglyceride levels and showed improvement in fibrosis, inflammation, and plasma ALT. Taken together, our studies indicate that mitochondrial uncouplers have potential for the treatment of NASH.
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- 2020
30. CDP-DAG synthase 1 and 2 regulate lipid droplet growth through distinct mechanisms
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Hongyuan Yang, Ximing Du, Yang E. Li, Xun Huang, Kyle L. Hoehn, Yanqing Xu, Hoi Yin Mak, and Ivan Lukmantara
- Subjects
0301 basic medicine ,Phosphatidic Acids ,Biochemistry ,Cell Line ,03 medical and health sciences ,chemistry.chemical_compound ,Lipid droplet ,Organelle ,Humans ,Diacylglycerol O-Acyltransferase ,Molecular Biology ,Diacylglycerol kinase ,CDS1 ,Gene knockdown ,030102 biochemistry & molecular biology ,Chemistry ,Effector ,Lipid Droplets ,Cell Biology ,Phosphatidic acid ,Lipids ,Cell biology ,030104 developmental biology ,Gene Knockdown Techniques ,Diacylglycerol Cholinephosphotransferase ,lipids (amino acids, peptides, and proteins) ,Biogenesis - Abstract
Lipid droplets (LDs) are evolutionarily conserved organelles that play critical roles in mammalian lipid storage and metabolism. However, the molecular mechanisms governing the biogenesis and growth of LDs remain poorly understood. Phosphatidic acid (PA) is a precursor of phospholipids and triacylglycerols and substrate of CDP-diacylglycerol (CDP-DAG) synthase 1 (CDS1) and CDS2, which catalyze the formation of CDP-DAG. Here, using siRNA-based gene knockdowns and CRISPR/Cas9-mediated gene knockouts, along with immunological, molecular, and fluorescence microscopy approaches, we examined the role of CDS1 and CDS2 in LD biogenesis and growth. Knockdown of either CDS1 or CDS2 expression resulted in the formation of giant or supersized LDs in cultured mammalian cells. Interestingly, down-regulation of cell death-inducing DFF45-like effector C (CIDEC), encoding a prominent regulator of LD growth in adipocytes, restored LD size in CDS1- but not in CDS2-deficient cells. On the other hand, reducing expression of two enzymes responsible for triacylglycerol synthesis, diacylglycerol O-acyltransferase 2 (DGAT2) and glycerol-3-phosphate acyltransferase 4 (GPAT4), rescued the LD phenotype in CDS2-deficient, but not CDS1-deficient, cells. Moreover, CDS2 deficiency, but not CDS1 deficiency, promoted the LD association of DGAT2 and GPAT4 and impaired initial LD maturation. Finally, although both CDS1 and CDS2 appeared to regulate PA levels on the LD surface, CDS2 had a stronger effect. We conclude that CDS1 and CDS2 regulate LD dynamics through distinct mechanisms.
- Published
- 2019
31. Proteomic pathways to metabolic disease and type 2 diabetes in the pancreatic islet
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Gregory J. Cooney, Alexis Diaz-Vegas, Dillon Jevon, Sheyda Naghiloo, Kyle L. Hoehn, Sing-Young Chen, Belinda Yau, Melkam A. Kebede, Austin V Carr, Amanda E. Brandon, Elise J. Needham, Lloyd M. Smith, Mark P. Keller, David E. James, Michael R. Shortreed, Mark Larance, Sean J. Humphrey, Julian Van Gerwen, Laurance Macia, and Peter Thorn
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geography ,endocrine system ,Multidisciplinary ,geography.geographical_feature_category ,endocrine system diseases ,Pancreatic islets ,Strain (biology) ,diabetology ,Science ,Type 2 diabetes ,Biology ,Proteomics ,Islet ,medicine.disease ,Phenotype ,Article ,Cell biology ,animal physiology ,medicine.anatomical_structure ,proteomics ,Proteome ,medicine ,Function (biology) - Abstract
Summary Pancreatic islets are essential for maintaining physiological blood glucose levels, and declining islet function is a hallmark of type 2 diabetes. We employ mass spectrometry-based proteomics to systematically analyze islets from 9 genetic or diet-induced mouse models representing a broad cross-section of metabolic health. Quantifying the islet proteome to a depth of >11,500 proteins, this study represents the most detailed analysis of mouse islet proteins to date. Our data highlight that the majority of islet proteins are expressed in all strains and diets, but more than half of the proteins vary in expression levels, principally due to genetics. Associating these varied protein expression levels on an individual animal basis with individual phenotypic measures reveals islet mitochondrial function as a major positive indicator of metabolic health regardless of strain. This compendium of strain-specific and dietary changes to mouse islet proteomes represents a comprehensive resource for basic and translational islet cell biology., Graphical abstract, Highlights • Most comprehensive mouse islet proteome library generated to date • Quantification of islet proteomic changes across 6 strains of mice on 2 diets • Islet mitochondrial function revealed as strain-independent regulator of metabolic health, Animal physiology; Diabetology; Proteomics.
- Published
- 2021
32. Targeting host metabolism by inhibition of acetyl-Coenzyme A carboxylase reduces flavivirus infection in mouse models
- Author
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Nereida Jiménez de Oya, Francisco Sobrino, David E. James, Priscila Ramos-Ibeas, Josefina Casas, Estela Escribano-Romero, Kyle L. Hoehn, Andrés Louloudes-Lázaro, Ayman El-Kattan, Ana-Belén Blázquez, Juan-Carlos Saiz, William P. Esler, Georgios Karamanlidis, Kim Huard, Miguel A. Martín-Acebes, Alfonso Gutiérrez-Adán, and Ministerio de Economía y Competitividad (España)
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0301 basic medicine ,Male ,Epidemiology ,viruses ,030106 microbiology ,Immunology ,Biology ,Dengue virus ,medicine.disease_cause ,Virus Replication ,Microbiology ,Antiviral Agents ,Article ,Zika virus ,Dengue ,03 medical and health sciences ,Mice ,antivirals ,Acetyl-coenzyme A carboxylase ,Virology ,Drug Discovery ,Antivirus ,medicine ,Animals ,Humans ,Enzyme Inhibitors ,dengue virus ,Host (biology) ,Zika Virus Infection ,Flavivirus ,RNA ,virus diseases ,Lipid metabolism ,General Medicine ,Metabolism ,Zika Virus ,biology.organism_classification ,Disease Models, Animal ,030104 developmental biology ,Infectious Diseases ,Parasitology ,Female ,West Nile virus ,West Nile Fever ,Acetyl-CoA Carboxylase - Abstract
Flaviviruses are (re)-emerging RNA viruses strictly dependent on lipid metabolism for infection. In the search for host targeting antivirals, we explored the effect of pharmacological modulation of fatty acid metabolism during flavivirus infection. Considering the central role of acetyl-Coenzyme A carboxylase (ACC) on fatty acid metabolism, we analyzed the effect of three small-molecule ACC inhibitors (PF-05175157, PF-05206574, and PF-06256254) on the infection of medically relevant flaviviruses, namely West Nile virus (WNV), dengue virus, and Zika virus. Treatment with these compounds inhibited the multiplication of the three viruses in cultured cells. PF-05175157 induced a reduction of the viral load in serum and kidney in WNV-infected mice, unveiling its therapeutic potential for the treatment of chronic kidney disease associated with persistent WNV infection. This study constitutes a proof of concept of the reliability of ACC inhibitors to become viable antiviral candidates. These results support the repositioning of metabolic inhibitors as broad-spectrum antivirals., This work was supported by Spanish Ministry of Economy and Competitiveness (MINECO) Fondo Europeo de Desarrollo Regional (FEDER) under Grant AGL2014-56518-JIN to M.A.M-A; INIA under Grant RTA2015-009 to J.-C.S.; and the Comunidad Autónoma de Madrid under Grant P2013/ABI-2906 (PLATESA) to J.-C.S and F.S. We thank the Pfizer Compound Transfer Program (Grants WI215864 and WI201531 to M.A.M.-A.) for providing the ACC inhibitors for cell culture and in vivo assays.
- Published
- 2019
33. Characterization of Glucose Transporter 6 in Lipopolysaccharide-Induced Bone Marrow–Derived Macrophage Function
- Author
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Kate G. R. Quinlan, Frances L. Byrne, Alexander J. Knights, Beth T. Caruana, and Kyle L. Hoehn
- Subjects
Lipopolysaccharides ,Glucose uptake ,medicine.medical_treatment ,Immunology ,Glucose Transport Proteins, Facilitative ,Context (language use) ,Bone marrow-derived macrophage ,Mice ,03 medical and health sciences ,0302 clinical medicine ,Downregulation and upregulation ,medicine ,Animals ,Immunology and Allergy ,Macrophage ,Mice, Knockout ,biology ,Chemistry ,Macrophages ,Glucose transporter ,Cell Differentiation ,Cell biology ,Cytokine ,biology.protein ,GLUT1 ,030215 immunology - Abstract
The polarization processes for M1 versus M2 macrophages are quite distinct in the context of changes in cellular metabolism. M1 macrophages are highly glycolytic, whereas M2 macrophages require a more oxidative nutrient metabolism. An important part of M1 polarization involves upregulation of the glucose transporter (GLUT) GLUT1 to facilitate increased glucose uptake and glycolytic metabolism; however, the role of other glucose transporters in this process is largely unknown. In surveying the Functional Annotation of the Mammalian Genome and Gene Expression Omnibus Profiles databases, we discovered that the glucose transporter GLUT6 is highly upregulated in LPS-activated macrophages. In our previous work, we have not detected mouse GLUT6 protein expression in any noncancerous tissue; therefore, in this study, we investigated the expression and significance of GLUT6 in bone marrow–derived macrophages from wild-type and GLUT6 knockout C57BL/6 mice. We show that LPS-induced M1 polarization markedly upregulated GLUT6 protein, whereas naive macrophages and IL-4–induced M2 macrophages do not express GLUT6 protein. However, despite strong upregulation of GLUT6 in M1 macrophages, the absence of GLUT6 did not alter M1 polarization in the context of glucose uptake, glycolytic metabolism, or cytokine production. Collectively, these data show that GLUT6 is dispensable for LPS-induced M1 polarization and function. These findings are important because GLUT6 is an anticancer drug target, and this study suggests that inhibition of GLUT6 may not impart detrimental side effects on macrophage function to interfere with their antitumor properties.
- Published
- 2019
34. Increased glucosylceramide production leads to decreased cell energy metabolism and lowered tumor marker expression in non-cancerous liver cells
- Author
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Bernhard Brüne, Catherine Olesch, Sandra Trautmann, Nerea Ferreirós, Frances L. Byrne, Nina Schömel, Kyle L. Hoehn, Ellen M. Olzomer, Gerd Geisslinger, Andreas Weigert, Marthe-Susanna Wegner, Robert Gurke, and Publica
- Subjects
Mitochondrial ROS ,Liver tumor ,Carcinoma, Hepatocellular ,Cell ,Glucosylceramides ,Glycosphingolipids ,Cell Line ,Cellular and Molecular Neuroscience ,Lactosylceramide ,Mice ,medicine ,Biomarkers, Tumor ,Animals ,Oxidative phosphorylation ,music ,Molecular Biology ,GEMs ,Tumor marker ,Pharmacology ,music.instrument ,Chemistry ,Liver Neoplasms ,Cancer ,Cell Biology ,medicine.disease ,Drug Resistance, Multiple ,Mitochondria ,medicine.anatomical_structure ,Liver ,Glucosyltransferases ,HCC marker ,Hepatocellular carcinoma ,Cancer research ,Molecular Medicine ,Original Article ,Liver cancer ,Energy Metabolism ,Glycolysis ,Signal Transduction - Abstract
Hepatocellular carcinoma (HCC) is one of the most difficult cancer types to treat. Liver cancer is often diagnosed at late stages and therapeutic treatment is frequently accompanied by development of multidrug resistance. This leads to poor outcomes for cancer patients. Understanding the fundamental molecular mechanisms leading to liver cancer development is crucial for developing new therapeutic approaches, which are more efficient in treating cancer. Mice with a liver specific UDP-glucose ceramide glucosyltransferase (UGCG) knockout (KO) show delayed diethylnitrosamine (DEN)-induced liver tumor growth. Accordingly, the rationale for our study was to determine whether UGCG overexpression is sufficient to drive cancer phenotypes in liver cells. We investigated the effect of UGCG overexpression (OE) on normal murine liver (NMuLi) cells. Increased UGCG expression results in decreased mitochondrial respiration and glycolysis, which is reversible by treatment with EtDO-P4, an UGCG inhibitor. Furthermore, tumor markers such as FGF21 and EPCAM are lowered following UGCG OE, which could be related to glucosylceramide (GlcCer) and lactosylceramide (LacCer) accumulation in glycosphingolipid-enriched microdomains (GEMs) and subsequently altered signaling protein phosphorylation. These cellular processes lead to decreased proliferation in NMuLi/UGCG OE cells. Our data show that increased UGCG expression itself does not induce pro-cancerous processes in normal liver cells, which indicates that increased GlcCer expression leads to different outcomes in different cancer types.
- Published
- 2021
35. Mitochondrial uncoupler SHC517 reverses obesity in mice without affecting food intake
- Author
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Sing-Young Chen, Simon P. Tucker, Stefan R. Hargett, Elizabeth S. Childress, Martina Beretta, Kyle L. Hoehn, Kate G. R. Quinlan, Stephanie J. Alexopoulos, Webster L. Santos, Isabella Aleksovska, Charles G. Cranfield, Divya P. Shah, Ellen M. Olzomer, Joseph M. Salamoun, Tristan Rawling, Ariane Roseblade, and Margaret J. Morris
- Subjects
0301 basic medicine ,Male ,medicine.medical_specialty ,Food intake ,Endocrinology, Diabetes and Metabolism ,medicine.medical_treatment ,030209 endocrinology & metabolism ,Diet, High-Fat ,Small Molecule Libraries ,03 medical and health sciences ,chemistry.chemical_compound ,Eating ,Mice ,0302 clinical medicine ,Endocrinology ,Metabolic Diseases ,In vivo ,Internal medicine ,medicine ,Animals ,Insulin ,Obesity ,Adiposity ,business.industry ,Cholesterol ,Body Weight ,Calorimetry, Indirect ,Metabolism ,medicine.disease ,Lipid Metabolism ,Mitochondria ,Respiratory quotient ,Mice, Inbred C57BL ,030104 developmental biology ,Glucose ,chemistry ,Diet, Western ,Lean body mass ,Insulin Resistance ,business ,Energy Metabolism - Abstract
Aims Mitochondrial uncouplers decrease caloric efficiency and have potential therapeutic benefits for the treatment of obesity and related metabolic disorders. Herein we investigate the metabolic and physiologic effects of a recently identified small molecule mitochondrial uncoupler named SHC517 in a mouse model of diet-induced obesity. Methods SHC517 was administered as an admixture in food. The effect of SHC517 on in vivo energy expenditure and respiratory quotient was determined by indirect calorimetry. A dose-finding obesity prevention study was performed by starting SHC517 treatment concomitant with high fat diet for a period of 12 days. An obesity reversal study was performed by feeding mice western diet for 4 weeks prior to SHC517 treatment for 7 weeks. Biochemical assays were used to determine changes in glucose, insulin, triglycerides, and cholesterol. SHC517 concentrations were determined by mass spectrometry. Results SHC517 increased lipid oxidation without affecting body temperature. SHC517 prevented diet-induced obesity when administered at 0.05% and 0.1% w/w in high fat diet and reversed established obesity when tested at the 0.05% dose. In the obesity reversal model, SHC517 restored adiposity to levels similar to chow-fed control mice without affecting food intake or lean body mass. SHC517 improved glucose tolerance and fasting glucose levels when administered in both the obesity prevention and obesity reversal modes. Conclusions SHC517 is a mitochondrial uncoupler with potent anti-obesity and insulin sensitizing effects in mice. SHC517 reversed obesity without altering food intake or compromising lean mass, effects that are highly sought-after in anti-obesity therapeutics.
- Published
- 2020
36. BAM15‐mediated mitochondrial uncoupling protects against obesity and improves glycemic control
- Author
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Jacob T. Mey, Gangarao Davuluri, Ciaran E. Fealy, Anny Mulya, Ingeborg M. Langohr, Elizabeth R M Zunica, Kathryn Pergola, Charles L. Hoppel, Christopher L. Axelrod, Kelly M. Fitzgerald, Krisztian Stadler, Michaela Hull, Hisashi Fujioka, Haylee Doyle, Stephanie J. Alexopoulos, Kyle L. Hoehn, Eva Schmidt, Robert C. Noland, Robbie A. Beyl, Stephan Nieuwoudt, Wagner S Dantas, Jacob Hall, John P. Kirwan, and William T. King
- Subjects
Male ,0301 basic medicine ,AMPK ,obesity ,Medicine (General) ,medicine.medical_treatment ,BAM15 ,Glycemic Control ,Type 2 diabetes ,Pharmacology ,Mitochondrion ,QH426-470 ,Diet, High-Fat ,Article ,Mice ,03 medical and health sciences ,0302 clinical medicine ,R5-920 ,Weight loss ,Chemical Biology ,medicine ,Genetics ,Animals ,Glycemic ,Uncoupling Agents ,business.industry ,Insulin ,Lipid metabolism ,Articles ,medicine.disease ,Mice, Inbred C57BL ,mitochondria ,Metabolism ,Glucose ,030104 developmental biology ,Molecular Medicine ,type 2 diabetes ,Insulin Resistance ,medicine.symptom ,Energy Metabolism ,business ,030217 neurology & neurosurgery ,Homeostasis - Abstract
Obesity is a leading cause of preventable death worldwide. Despite this, current strategies for the treatment of obesity remain ineffective at achieving long‐term weight control. This is due, in part, to difficulties in identifying tolerable and efficacious small molecules or biologics capable of regulating systemic nutrient homeostasis. Here, we demonstrate that BAM15, a mitochondrially targeted small molecule protonophore, stimulates energy expenditure and glucose and lipid metabolism to protect against diet‐induced obesity. Exposure to BAM15 in vitro enhanced mitochondrial respiratory kinetics, improved insulin action, and stimulated nutrient uptake by sustained activation of AMPK. C57BL/6J mice treated with BAM15 were resistant to weight gain. Furthermore, BAM15‐treated mice exhibited improved body composition and glycemic control independent of weight loss, effects attributable to drug targeting of lipid‐rich tissues. We provide the first phenotypic characterization and demonstration of pre‐clinical efficacy for BAM15 as a pharmacological approach for the treatment of obesity and related diseases., This study presents a novel therapy for treatment of obesity‐related diseases. Oral delivery of the mitochondrial protonophore BAM15 markedly reduced weight gain and fat accrual while improving glycemic control.
- Published
- 2020
37. Eosinophil function in adipose tissue is regulated by Krüppel-like factor 3 (KLF3)
- Author
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Kate G. R. Quinlan, Jinfen J. Yik, Alexander J. Knights, Hanapi Mat Jusoh, Peter J. Houweling, Kyle L. Hoehn, Laura J. Norton, Ellen M. Olzomer, Elizabeth S. Stout, Merlin Crossley, Kathryn N. North, Stephanie J. Alexopoulos, Emily J. Vohralik, and Kim S. Bell-Anderson
- Subjects
Male ,0301 basic medicine ,Chromatin Immunoprecipitation ,Science ,Kruppel-Like Transcription Factors ,General Physics and Astronomy ,Adipose tissue ,Inflammation ,Biology ,Article ,General Biochemistry, Genetics and Molecular Biology ,Transcriptome ,Mice ,03 medical and health sciences ,0302 clinical medicine ,Immune system ,Chlorocebus aethiops ,Transcriptional regulation ,medicine ,Animals ,Obesity ,lcsh:Science ,Adiposity ,Multidisciplinary ,General Chemistry ,Eosinophil ,Flow Cytometry ,Gene regulation ,Cell biology ,Eosinophils ,030104 developmental biology ,medicine.anatomical_structure ,Adipose Tissue ,COS Cells ,KLF3 ,lcsh:Q ,medicine.symptom ,Thermogenesis ,Software ,030217 neurology & neurosurgery ,Signal Transduction - Abstract
The conversion of white adipocytes to thermogenic beige adipocytes represents a potential mechanism to treat obesity and related metabolic disorders. However, the mechanisms involved in converting white to beige adipose tissue remain incompletely understood. Here we show profound beiging in a genetic mouse model lacking the transcriptional repressor Krüppel-like factor 3 (KLF3). Bone marrow transplants from these animals confer the beige phenotype on wild type recipients. Analysis of the cellular and molecular changes reveal an accumulation of eosinophils in adipose tissue. We examine the transcriptomic profile of adipose-resident eosinophils and posit that KLF3 regulates adipose tissue function via transcriptional control of secreted molecules linked to beiging. Furthermore, we provide evidence that eosinophils may directly act on adipocytes to drive beiging and highlight the critical role of these little-understood immune cells in thermogenesis., Immune cells are important regulators of adipose tissue function, including adaptive thermogenesis. Here the authors show that mice with Krüppel-like factor 3 (KLF3) deficiency in bone marrow-derived cells have increased adipose tissue beiging which may at least in part be due to altered eosinophil paracrine signaling.
- Published
- 2020
38. Mitochondrial uncoupler BAM15 reverses diet-induced obesity and insulin resistance in mice
- Author
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Carolin Lackner, Robert T. Lawrence, Brendan Lee, Christopher J Garcia, Nigel Turner, Ellen M. Olzomer, Amanda E. Brandon, Joseph M. Salamoun, Divya P. Shah, Sing-Young Chen, Ashleigh M. Philp, Andrew Philp, Simon P. Tucker, Stephanie J. Alexopoulos, Pascal Carrive, Stefan R. Hargett, Webster L. Santos, Kyle L. Hoehn, Frances L. Byrne, James Sligar, Martina Beretta, and Gregory J. Cooney
- Subjects
Blood Glucose ,Male ,0301 basic medicine ,Antioxidant ,medicine.medical_treatment ,Administration, Oral ,General Physics and Astronomy ,02 engineering and technology ,Body Temperature ,Mice ,lcsh:Science ,Membrane Potential, Mitochondrial ,Oxadiazoles ,Multidisciplinary ,Glucose clamp technique ,021001 nanoscience & nanotechnology ,Metabolic syndrome ,Mitochondria ,Dose–response relationship ,Adipose Tissue ,Liver ,Pyrazines ,Toxicity ,0210 nano-technology ,medicine.medical_specialty ,Science ,Diamines ,Article ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,Insulin resistance ,Internal medicine ,medicine ,Animals ,Humans ,Obesity ,Dose-Response Relationship, Drug ,business.industry ,Insulin ,Body Weight ,General Chemistry ,medicine.disease ,Disease Models, Animal ,Oxidative Stress ,030104 developmental biology ,Endocrinology ,Diet, Western ,Glucose Clamp Technique ,Lean body mass ,lcsh:Q ,Insulin Resistance ,business - Abstract
Obesity is a health problem affecting more than 40% of US adults and 13% of the global population. Anti-obesity treatments including diet, exercise, surgery and pharmacotherapies have so far failed to reverse obesity incidence. Herein, we target obesity with a pharmacotherapeutic approach that decreases caloric efficiency by mitochondrial uncoupling. We show that a recently identified mitochondrial uncoupler BAM15 is orally bioavailable, increases nutrient oxidation, and decreases body fat mass without altering food intake, lean body mass, body temperature, or biochemical and haematological markers of toxicity. BAM15 decreases hepatic fat, decreases inflammatory lipids, and has strong antioxidant effects. Hyperinsulinemic-euglycemic clamp studies show that BAM15 improves insulin sensitivity in multiple tissue types. Collectively, these data demonstrate that pharmacologic mitochondrial uncoupling with BAM15 has powerful anti-obesity and insulin sensitizing effects without compromising lean mass or affecting food intake., Obesity is a global pandemic with limited treatment options. Here, the authors show evidence in mice that the mitochondrial uncoupler BAM15 effectively induces fat loss without affecting food intake or compromising lean body mass.
- Published
- 2020
39. Anilinopyrazines as potential mitochondrial uncouplers
- Author
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Stefan R. Hargett, Murray Jacob H, Webster L. Santos, and Kyle L. Hoehn
- Subjects
Pyrazine ,Protonophore ,Clinical Biochemistry ,Pharmaceutical Science ,Oxidative phosphorylation ,01 natural sciences ,Biochemistry ,chemistry.chemical_compound ,Structure-Activity Relationship ,Aniline ,Proton transport ,Drug Discovery ,Inner mitochondrial membrane ,Molecular Biology ,Trifluoromethyl ,Aniline Compounds ,Dose-Response Relationship, Drug ,Molecular Structure ,010405 organic chemistry ,Chemiosmosis ,Uncoupling Agents ,Organic Chemistry ,0104 chemical sciences ,Mitochondria ,010404 medicinal & biomolecular chemistry ,chemistry ,Pyrazines ,Biophysics ,Molecular Medicine ,Reactive Oxygen Species - Abstract
Mitochondrial protonophores transport protons through the mitochondrial inner membrane into the matrix to uncouple nutrient oxidation from ATP production thereby decreasing the proton motive force. Mitochondrial uncouplers have beneficial effects of decrease reactive oxygen species generation and have the potential for treating diseases such as obesity, neurodegenerative diseases, non-alcoholic fatty liver disease (NAFLD), diabetes, and many others. In this study, we report the structure-activity relationship profile of the pyrazine scaffold bearing substituted aniline rings. Our work indicates that a trifluoromethyl group is best at the para position while the trifluoromethoxy group is preferred in the meta position of the aniline rings of 2,3-substituted pyrazines. As proton transport and cycling requires the formation of a negative charge that has to traverse the mitochondrial membrane, a stabilizing internal hydrogen bond is a key feature for efficient mitochondrial uncoupling activity.
- Published
- 2019
40. A selective inhibitor of ceramide synthase 1 reveals a novel role in fat metabolism
- Author
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Kyle L. Hoehn, Corrine E. Fiveash, Greg M. Kowalski, Jonathan D. Teo, Carsten Schmitz-Peiffer, Timothy A. Couttas, Hemna Govindaraju, Magdalene K. Montgomery, Gregory J. Cooney, Amanda E. Brandon, Anthony S. Don, Brenna Osborne, Jonathan C. Morris, Nigel Turner, Abhirup Das, Holly P. McEwen, Thomas Fath, Hamish D. Toop, Elysha N. Taylor, Xin Ying Lim, Clinton R. Bruce, and Stephen M. Butler
- Subjects
Male ,0301 basic medicine ,Ceramide ,Science ,Cell Respiration ,General Physics and Astronomy ,Adipose tissue ,Diet, High-Fat ,Article ,General Biochemistry, Genetics and Molecular Biology ,Inhibitory Concentration 50 ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Insulin resistance ,medicine ,Animals ,Humans ,Enzyme Inhibitors ,Muscle, Skeletal ,lcsh:Science ,Ceramide synthase ,Beta oxidation ,Sphingolipids ,Multidisciplinary ,Chemistry ,Fatty Acids ,Skeletal muscle ,Ceramide synthase 1 ,General Chemistry ,Lipid Metabolism ,medicine.disease ,Sphingolipid ,Mitochondria ,3. Good health ,Mice, Inbred C57BL ,HEK293 Cells ,030104 developmental biology ,medicine.anatomical_structure ,Liver ,Biochemistry ,lcsh:Q ,Insulin Resistance ,Oxidoreductases ,Oxidation-Reduction ,030217 neurology & neurosurgery - Abstract
Specific forms of the lipid ceramide, synthesized by the ceramide synthase enzyme family, are believed to regulate metabolic physiology. Genetic mouse models have established C16 ceramide as a driver of insulin resistance in liver and adipose tissue. C18 ceramide, synthesized by ceramide synthase 1 (CerS1), is abundant in skeletal muscle and suggested to promote insulin resistance in humans. We herein describe the first isoform-specific ceramide synthase inhibitor, P053, which inhibits CerS1 with nanomolar potency. Lipidomic profiling shows that P053 is highly selective for CerS1. Daily P053 administration to mice fed a high-fat diet (HFD) increases fatty acid oxidation in skeletal muscle and impedes increases in muscle triglycerides and adiposity, but does not protect against HFD-induced insulin resistance. Our inhibitor therefore allowed us to define a role for CerS1 as an endogenous inhibitor of mitochondrial fatty acid oxidation in muscle and regulator of whole-body adiposity., Ceramides are signalling molecules that regulate several physiological functions including insulin sensitivity. Here the authors report a selective ceramide synthase 1 inhibitor that counteracts lipid accumulation within the muscle and adiposity by increasing fatty acid oxidation but without affecting insulin sensitivity in mice fed with an obesogenic diet.
- Published
- 2018
41. UGCG influences glutamine metabolism of breast cancer cells
- Author
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Marthe-Susanna Wegner, Ellen M. Olzomer, Nina Schömel, Sabine Grösch, Lisa Gruber, Gerd Geisslinger, Frances L. Byrne, Divya P. Shah, Nigel Turner, Sarah E. Hancock, and Kyle L. Hoehn
- Subjects
0301 basic medicine ,Glutamine ,Glucose Transport Proteins, Facilitative ,lcsh:Medicine ,Breast Neoplasms ,Reductase ,medicine.disease_cause ,Article ,03 medical and health sciences ,chemistry.chemical_compound ,Breast cancer ,0302 clinical medicine ,medicine ,Humans ,RNA, Messenger ,lcsh:Science ,chemistry.chemical_classification ,Multidisciplinary ,lcsh:R ,Glycosphingolipid ,Glutathione ,Metabolism ,Cancer metabolism ,Sphingolipid ,Gene Expression Regulation, Neoplastic ,Oxidative Stress ,Glucose ,030104 developmental biology ,Enzyme ,chemistry ,Biochemistry ,Glucosyltransferases ,030220 oncology & carcinogenesis ,MCF-7 Cells ,lcsh:Q ,Energy Metabolism ,Oxidation-Reduction ,Oxidative stress - Abstract
UDP-glucose ceramide glucosyltransferase (UGCG) is the key enzyme in glycosphingolipid (GSL) metabolism by being the only enzyme that generates glucosylceramide (GlcCer) de novo. Increased UGCG synthesis is associated with pro-cancerous processes such as increased proliferation and multidrug resistance in several cancer types. We investigated the influence of UGCG overexpression on glutamine metabolism in breast cancer cells. We observed adapted glucose and glutamine uptake in a limited energy supply environment following UGCG overexpression. Glutamine is used for reinforced oxidative stress response shown by increased mRNA expression of glutamine metabolizing proteins such as glutathione-disulfide reductase (GSR) resulting in increased reduced glutathione (GSH) level. Augmented glutamine uptake is also used for fueling the tricarboxylic acid (TCA) cycle to maintain the proliferative advantage of UGCG overexpressing cells. Our data reveal a link between GSL and glutamine metabolism in breast cancer cells, which is to our knowledge a novel correlation in the field of sphingolipid research.
- Published
- 2019
42. Small Molecule Mitochondrial Uncouplers and Their Therapeutic Potential
- Author
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Webster L. Santos, Elizabeth S. Childress, Kyle L. Hoehn, and Stephanie J. Alexopoulos
- Subjects
0301 basic medicine ,ATP synthase ,biology ,Chemistry ,Metabolism ,Small molecule ,Drug synergism ,Cell biology ,03 medical and health sciences ,030104 developmental biology ,Biochemistry ,Mitochondrial matrix ,Drug Discovery ,biology.protein ,Molecular Medicine ,Inner mitochondrial membrane - Abstract
Small molecule mitochondrial uncouplers transport protons from the mitochondrial inner membrane space into the mitochondrial matrix independent of ATP synthase, uncoupling nutrient metabolism from ATP generation. The therapeutic potential of mitochondrial uncouplers has been investigated for the treatment of metabolic diseases such as obesity and type 2 diabetes (T2D), ischemia–reperfusion injury, and neurodegenerative diseases. This communication will review the small molecule mitochondrial uncouplers reported to date and explore their potential as therapeutics.
- Published
- 2017
43. STEAP4 expression in human islets is associated with differences in body mass index, sex, HbA1c, and inflammation
- Author
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Neil Majithia, Linda Langman, Kenneth L. Brayman, Patrick E. MacDonald, Kyle L. Hoehn, Poonam Sharma, Frances L. Byrne, Craig S. Nunemaker, Carmella Evans-Molina, Hannah M. Gordon, and Jocelyn E. Manning Fox
- Subjects
Adult ,Male ,0301 basic medicine ,medicine.medical_specialty ,Endocrinology, Diabetes and Metabolism ,Inflammation ,Type 2 diabetes ,Biology ,Article ,Body Mass Index ,Islets of Langerhans ,03 medical and health sciences ,Sex Factors ,Endocrinology ,Antigen ,Prostate ,Internal medicine ,Diabetes mellitus ,medicine ,Humans ,Obesity ,Aged ,Glycated Hemoglobin ,geography ,geography.geographical_feature_category ,Membrane Proteins ,Middle Aged ,medicine.disease ,Islet ,030104 developmental biology ,medicine.anatomical_structure ,Diabetes Mellitus, Type 2 ,Immunology ,Female ,medicine.symptom ,Oxidoreductases ,Body mass index - Abstract
STEAP4 (six-transmembrane epithelial antigen of the prostate 4) is a metalloreductase that has been shown previously to protect cells from inflammatory damage. Genetic variants in STEAP4 have been associated with numerous metabolic disorders related to obesity, including putative defects in the acute insulin response to glucose in type 2 diabetes.We examined whether obesity and/or type 2 diabetes altered STEAP4 expression in human pancreatic islets.Human islets were isolated from deceased donors at two medical centers and processed for quantitative polymerase chain reaction. Organ donors were selected by status as non-diabetic or having type 2 diabetes. Site 1 (Edmonton): N = 13 type 2 diabetes donors (7M, 6F), N = 20 non-diabetic donors (7M, 13F). Site 2 (Virginia): N = 6 type 2 diabetes donors (6F), N = 6 non-diabetic donors (3M, 3F).STEAP4 showed reduced islet expression with increasing body mass index among all donors (P 0.10) and non-diabetic donors (P 0.05) from Site 1; STEAP4 showed reduced islet expression among type 2 diabetes donors with increasing hemoglobin A1c. Islet STEAP4 expression was also marginally higher in female donors (P 0.10). Among type 2 diabetes donors from Site 2, islet insulin expression was reduced, STEAP4 expression was increased, and white blood cell counts were increased compared to non-diabetic donors. Islets from non-diabetic donors that were exposed overnight to 5 ng/ml IL-1β displayed increased STEAP4 expression, consistent with STEAP4 upregulation by inflammatory signaling.These findings suggest that increased STEAP4 mRNA expression is associated with inflammatory stimuli, whereas lower STEAP4 expression is associated with obesity in human islets. Given its putative protective role, downregulation of STEAP4 by chronic obesity suggests a mechanism for reduced islet protection against cellular damage.
- Published
- 2017
44. Transcriptome landscape of long intergenic non-coding RNAs in endometrial cancer
- Author
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Rhonda Farrell, Konii Takenaka, Kyle L. Hoehn, Susan C. Modesitt, Ellen M. Olzomer, Bei Jun Chen, Frances L. Byrne, James D. Mills, Michael Janitz, and Other departments
- Subjects
0301 basic medicine ,Uterine Cervical Neoplasms ,RNA-Seq ,Biology ,Endometrium ,Bioinformatics ,Transcriptome ,03 medical and health sciences ,Biopsy ,medicine ,Humans ,RNA, Neoplasm ,Gene ,Neoplasm Staging ,medicine.diagnostic_test ,Endometrial cancer ,Obstetrics and Gynecology ,Cancer ,medicine.disease ,Endometrial Neoplasms ,Up-Regulation ,030104 developmental biology ,medicine.anatomical_structure ,Oncology ,Organ Specificity ,Case-Control Studies ,Female ,RNA, Long Noncoding ,Human genome ,Oligopeptides - Abstract
Endometrial cancer is the most common gynecological malignancy in the developed world. It is the fifth most common cancer and accounts for 4.8% of all cancers in women. Long intergenic non-coding RNAs (lincRNAs), a subclass of long non-coding RNAs, are pervasively transcribed throughout the human genome. Objective. LincRNA expression patterns in endometrial cancer compared to normal healthy tissue are poorly characterised. In this study, the lincRNA transcriptome of endometrial cancers and adjacent normal endometrium from the same patients was sequenced and compared with transcriptomes of other gynaecologic malignancies including ovarian and cervical cancers. Methods. RNA was isolated from malignant and adjacent non-affected endometrial tissue from 6 patients with low grade and stage Type I endometrial cancer. Subsequently, Illumina paired-end RNA sequencing was performed, followed by bioinformatics analysis, to determine differential transcriptome expression patterns. Results. LINC00958 was upregulated in all three cancers, and four lincRNAs including LINC01480, LINC00645, LINC00891 and LINC00702 demonstrated exquisite specificity for malignant endometrium compared to normal endometrium while also distinguishing endometrial cancer from ovarian and cervical cancers. Furthermore, LINC01480 has features required to express a micropeptide. Conclusions. The lincRNAs, characterised in this study, represent high priority genes to be tested for functional significance in the pathogenesis and/or progression of endometrial cancer. Furthermore, lincRNAs have potential to be released into the bloodstream and therefore the four lincRNAs identified here may represent biomarkers for early detection of endometrial cancer without biopsy. (c) 2017 Elsevier Inc. All rights reserved
- Published
- 2017
45. The emerging role of long non-coding RNAs in endometrial cancer
- Author
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Susan C. Modesitt, Bei Jun Chen, Michael Janitz, Frances L. Byrne, Kyle L. Hoehn, and Konii Takenaka
- Subjects
0301 basic medicine ,Cancer Research ,Endometrial cancer ,Cancer ,RNA ,Disease ,Biology ,medicine.disease ,Bioinformatics ,Genome ,Endometrial Neoplasms ,Transcriptome ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,030220 oncology & carcinogenesis ,Gene expression ,Genetics ,medicine ,Humans ,Female ,RNA, Long Noncoding ,Human genome ,Molecular Biology - Abstract
The human genome is pervasively transcribed and approximately 98% of the genome is non-coding. Long non-coding RNAs (lncRNAs) are a heterogeneous group of RNA transcripts that are >200 nucleotides in length with minimal to no protein-coding potential. Similar to proteins, lncRNAs have important biological functions in both normal cells and disease states including many types of cancer. This review summarizes recent advances in our understanding of lncRNAs in cancer biology and highlights the potential for lncRNA as diagnostic biomarkers and therapeutics. Herein we focus on the poorly understood role of lncRNAs in endometrial cancer, the most common gynecologic malignancy in the developed world.
- Published
- 2016
46. Delivering bioactive cyclic peptides that target Hsp90 as prodrugs
- Author
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Shelli R. McAlpine, Kyle L. Hoehn, Jack L. Bennett, Yuantao Huo, Marwa N. Rahimi, Eloise C. Smith, Frances L. Byrne, and Laura K. Buckton
- Subjects
Masking (art) ,protein-protein interactions ,Peptides, Cyclic ,01 natural sciences ,Protein–protein interaction ,Mice ,Structure-Activity Relationship ,prodrugs ,Drug Discovery ,Animals ,Humans ,HSP90 Heat-Shock Proteins ,heat shock protein 90 ,Cell permeability ,Pharmacology ,chemistry.chemical_classification ,Dose-Response Relationship, Drug ,Molecular Structure ,biology ,010405 organic chemistry ,Chemistry ,lcsh:RM1-950 ,cell permeability ,General Medicine ,Prodrug ,Hsp90 ,Cyclic peptide ,0104 chemical sciences ,010404 medicinal & biomolecular chemistry ,lcsh:Therapeutics. Pharmacology ,Microsomes, Liver ,Biophysics ,biology.protein ,Peptide drug ,peptide drug delivery ,Target binding ,Research Paper - Abstract
The most challenging issue facing peptide drug development is producing a molecule with optimal physical properties while maintaining target binding affinity. Masking peptides with protecting groups that can be removed inside the cell, produces a cell-permeable peptide, which theoretically can maintain its biological activity. Described are series of prodrugs masked using: (a) O-alkyl, (b) N-alkyl, and (c) acetyl groups, and their binding affinity for Hsp90. Alkyl moieties increased compound permeability, Papp, from 3.3 to 5.6, however alkyls could not be removed by liver microsomes or in-vivo and their presence decreased target binding affinity (IC50 of ≥10 µM). Thus, unlike small molecules, peptide masking groups cannot be predictably removed; their removal is related to the 3-D conformation. O-acetyl groups were cleaved but are labile, increasing challenges during synthesis. Utilising acetyl groups coupled with mono-methylated amines may decrease the polarity of a peptide, while maintaining binding affinity., Graphical Abstract
- Published
- 2019
- Full Text
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47. Structure–activity relationships of furazano[3,4- b ]pyrazines as mitochondrial uncouplers
- Author
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Brandon M. Kenwood, Kyle L. Hoehn, Joseph A. Calderone, Evan P. Taddeo, and Webster L. Santos
- Subjects
Pyrazine ,Protonophore ,Clinical Biochemistry ,Pharmaceutical Science ,Furazan ,Biochemistry ,Article ,Structure-Activity Relationship ,chemistry.chemical_compound ,Adenosine Triphosphate ,Drug Discovery ,Atp production ,Molecular Biology ,Dose-Response Relationship, Drug ,Molecular Structure ,ATP synthase ,biology ,Uncoupling Agents ,Chemistry ,Organic Chemistry ,Carbonyl cyanide ,Mitochondrial respiration ,Mitochondria ,Mitochondrial matrix ,Pyrazines ,biology.protein ,Molecular Medicine ,Oxidation-Reduction - Abstract
Chemical mitochondrial uncouplers are lipophilic weak acids that transport protons into the mitochondrial matrix via a pathway that is independent of ATP synthase, thereby uncoupling nutrient oxidation from ATP production. These uncouplers have potential for the treatment of diseases such as obesity, Parkinson’s disease, and aging. We have previously identified a novel mitochondrial protonophore, named BAM15, which stimulates mitochondrial respiration across a broad dosing range compared to carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP). Herein, we report our investigations on the structure–activity relationship profile of BAM15. Our studies demonstrate the importance of the furazan, pyrazine, and aniline rings as well as pKa in maintaining its effective protonophore activity.
- Published
- 2015
48. Defining Eosinophil Function in Adiposity and Weight Loss
- Author
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Alexander J. Knights, Kate G. R. Quinlan, Kyle L. Hoehn, Emily J. Vohralik, and Merlin Crossley
- Subjects
0301 basic medicine ,Adipose tissue ,Mice, Obese ,Biology ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,Immune system ,Immunity ,Weight loss ,Weight Loss ,medicine ,Animals ,Homeostasis ,Humans ,Obesity ,Adiposity ,Eosinophil ,Eosinophils ,030104 developmental biology ,medicine.anatomical_structure ,Energy expenditure ,Adipose Tissue ,Immunology ,medicine.symptom ,Function (biology) - Abstract
Despite promising early work into the role of immune cells such as eosinophils in adipose tissue (AT) homeostasis, recent findings revealed that elevating the number of eosinophils in AT alone is insufficient for improving metabolic impairments in obese mice. Eosinophils are primarily recognized for their role in allergic immunity and defence against parasitic worms. They have also been detected in AT and appear to contribute to adipose homeostasis and drive energy expenditure, but the underlying mechanisms remain elusive. It has long been recognized that immune cells such as macrophages respond to external signals to regulate adipose homeostasis and energy balance, however, less is known about the relevance of eosinophil activity in AT. As the authors propose in this review, given recent debate over the relative importance of their tissue-specific abundance, the stage is now set for exploring the functionality and activation states of AT eosinophils.
- Published
- 2018
49. Abstract 428: An Unexpected Role for ACC in Lipid Droplet Formation in Macrophages in Response to Acellular Adipocyte Fat
- Author
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Vlad Serbulea, Srabani Sahu, Victoria Osinski, Thurl E. Harris, Norbert Leitinger, Kyle L. Hoehn, Clint M Upchurch, Coleen A. McNamara, Akshaya K. Meher, Alexander L. Klibanov, and Stefan R. Hargett
- Subjects
medicine.medical_specialty ,chemistry.chemical_compound ,CLs upper limits ,Endocrinology ,Chemistry ,Internal medicine ,Adipocyte ,Lipid droplet ,medicine ,Adipose tissue ,Cardiology and Cardiovascular Medicine ,Obese Mice - Abstract
In adipose tissues of obese mice, macrophages accumulate in crown-like structures (CLS) formed around dying adipocytes. The CLS macrophages are thought to clear the dead adipocytes by exophagy, which involves exocytosis of lysosomes and digestion of apoptotic adipocytes. After digesting the plasma membrane and other cytosolic contents of the adipocyte, CLS macrophages come in contact with the large lipid droplet, however, it is unknown how macrophages response to such acellular adipocytes. We hypothesized that the acelular adipocytes in CLSs promote inflammation and metabolically activate the macrophages to promote clearance of the lipid. To mimic the in vivo scenario, we exposed cultured murine bone marrow-derived macrophages to lipid droplets isolated from the adipocytes of high-fat diet-induced obese C57BL/6 mice. In response to adipocyte lipid, macrophages accumulated lipid droplets, which were similar in size and number to lipid droplets of CLS macrophages in vivo . Acellular lipid exposure significantly increased TNF-α gene expression, which was suppressed by the CD36 inhibitor sulfo-N-succinimidyl oleate, supporting CD36-mediated inflammatory response. Moreover, lipid exposure significantly lowered metabolic activity of macrophages and impaired clearance of apoptotic bodies from 3T3-L1 adipocytes. Using specific inhibitors, unexpectedly we found that lipid droplet accumulation in macrophages was independent of CD36 activity or processes involved in exophagy such as exocytosis of lysosomes, extracellular lipase activity, lipolysis and phagocytosis. Interestingly, lipid droplet accumulation was dependent on acetyl-CoA carboxylase (ACC) as determined by use of ACC inhibitors soraphen A and TOFA, and siRNA knock-down of ACC in macrophages. Furthermore, confocal microscopy of whole mount adipose tissue revealed expression of ACC in CLS macrophages. Altogether, using a novel in vitro model we demonstrate that acelular adipocytes suppress metabolic activity, but induce inflammation and de novo lipogenesis-mediated lipid droplet formation in macrophages.
- Published
- 2018
50. Knockout of glucose transporter GLUT6 has minimal effects on whole body metabolic physiology in mice
- Author
-
Kyle L. Hoehn, Ellen M. Olzomer, Frances L. Byrne, and Robert Brink
- Subjects
0301 basic medicine ,Blood Glucose ,Male ,medicine.medical_specialty ,Genotype ,Physiology ,Endocrinology, Diabetes and Metabolism ,Normal tissue ,Glucose Transport Proteins, Facilitative ,Biology ,03 medical and health sciences ,Mice ,Downregulation and upregulation ,Physiology (medical) ,Internal medicine ,medicine ,Animals ,Homeostasis ,Insulin ,Adiposity ,Mice, Knockout ,Body Weight ,Glucose transporter ,Metabolism ,Glucose Tolerance Test ,Diet ,030104 developmental biology ,Endocrinology ,Glucose ,Female ,CRISPR-Cas Systems ,Whole body ,Energy Metabolism - Abstract
Glucose transporter 6 (GLUT6) is a member of the facilitative glucose transporter family. GLUT6 is upregulated in several cancers but is not widely expressed in normal tissues. Previous studies have shown that GLUT6 knockdown kills endometrial cancer cells that express elevated levels of the protein. However, whether GLUT6 represents a viable anticancer drug target is unclear because the role of GLUT6 in normal metabolic physiology is unknown. Herein we generated GLUT6 knockout mice to determine how loss of GLUT6 affected whole body glucose homeostasis and metabolic physiology. We found that the mouse GLUT6 ( Slc2a6) gene expression pattern was similar to humans with mRNA found primarily in brain and spleen. CRISPR-Cas9-mediated deletion of Slc2a6 did not alter mouse development, growth, or whole body glucose metabolism in male or female mice fed either a chow diet or Western diet. GLUT6 deletion did not impact glucose tolerance or blood glucose and insulin levels in male or female mice fed either diet. However, compared with wild-type littermate controls, GLUT6 null female mice had a relatively minor decrease in fat accumulation when fed Western diet and had a lower respiratory exchange ratio when fed chow diet. Collectively, these data show that GLUT6 is not a major regulator of whole body metabolic physiology; therefore, GLUT6 inhibition may have minimal adverse effects if targeted for cancer therapy.
- Published
- 2018
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