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The high incidence of epithelial malignancies in HIV-1 infected individuals is associated with co-infection with oncogenic viruses, such as high-risk human papillomaviruses (HR HPVs), mostly HPV16. The molecular mechanisms underlying the HIV-1-associated increase in epithelial malignancies are not fully understood. A collaboration between HIV-1 and HR HPVs in the malignant transformation of epithelial cells has long been anticipated. Here, we delineated the effects of HIV-1 reverse transcriptase on the in vitro and in vivo properties of HPV16-infected cervical cancer cells. A human cervical carcinoma cell line infected with HPV16 (Ca Ski) was made to express HIV-1 reverse transcriptase (RT) by lentiviral transduction. The levels of the mRNA of the E6 isoforms and of the factors characteristic to the epithelial/mesenchymal transition were assessed by real-time RT-PCR. The parameters of glycolysis and mitochondrial respiration were determined using Seahorse technology. RT expressing Ca Ski subclones were assessed for the capacity to form tumors in nude mice. RT expression increased the expression of the E6*I isoform, modulated the expression of E-CADHERIN and VIMENTIN, indicating the presence of a hybrid epithelial/mesenchymal phenotype, enhanced glycolysis, and inhibited mitochondrial respiration. In addition, the expression of RT induced phenotypic alterations impacting cell motility, clonogenic activity, and the capacity of Ca Ski cells to form tumors in nude mice. These findings suggest that HIV-RT, a multifunctional protein, affects HPV16-induced oncogenesis, which is achieved through modulation of the expression of the E6 oncoprotein. These results highlight a complex interplay between HIV antigens and HPV oncoproteins potentiating the malignant transformation of epithelial cells.

Introduction: Familial hypercholesterolemia, the highly prevalent form of dyslipidemia, is a well-known risk factor for premature heart disease and stroke worldwide. Statins, which inhibit 3-hydroxy 3-methylglutaryl coenzyme A (HMG-CoA) reductase, are the first-choice treatment for dyslipidemias, and have been effective in reducing the risk of stroke and myocardial infarction. However, emerging evidence indicates that statins may increase the incidence of new-onset type 2 diabetes by reducing β-cell mass and function. Notably, past in vitro reports studying the effects of statins on β-cells were performed without including free fatty acids in the model. This factor should have been addressed since these agents are used to treat individuals with hyperlipidemia. Methods: Here, we used a mouse insulinoma MIN6 β-cell culture model to assess the efficacy, cytotoxicity, and insulin-suppressive effects of simvastatin and pravastatin in the presence of palmitic, linoleic, and oleic acids cocktail to mimic mixed lipids challenge in a biologically relevant setting. Results and discussion: Our findings indicate that simvastatin was more effective in lowering intracellular cholesterol but was more cytotoxic as compared to pravastatin. Similarly, simvastatin exhibited a higher suppression of total insulin content and insulin secretion. Both drugs suppressed insulin secretion in phases 1 and 2, dose-dependently. No significant effect was observed on mitochondrial respiration. More importantly, elution experiments showed that insulin content diminution by simvastatin treatment was reversible, while exogenous mevalonate did not improve total insulin content. This suggests that simvastatin's influence on insulin content is independent of its specific inhibitory action on HMG-CoA reductase. In conclusion, our study identified that simvastatin was more effective in lowering intracellular cholesterol, albeit it was more toxic and suppressive of β-cells function. Notably, this suppression was found to be reversible. [ABSTRACT FROM AUTHOR]

Objective: Pathological retinal neovascularization is vision-threatening. In mouse oxygen-induced retinopathy (OIR) we sought to define mitochondrial respiration changes longitudinally during hyperoxia-induced vessel loss and hypoxia-induced neovascularization, and to test interventions addressing those changes to prevent neovascularization. Methods: OIR was induced in C57BL/6J mice and retinal vasculature was examined at maximum neovessel formation. We assessed total proteome changes and the ratio of mitochondrial to nuclear DNA copy numbers (mtDNA/nDNA) of OIR vs. control retinas, and mitochondrial oxygen consumption rates (OCR) in ex vivo OIR vs. control retinas (BaroFuse). Pyruvate vs. vehicle control was supplemented to OIR mice either prior to or during neovessel formation. Results: In OIR vs. control retinas, global proteomics showed decreased retinal mitochondrial respiration at peak neovascularization. OCR and mtDNA/nDNA were also decreased at peak neovascularization suggesting impaired mitochondrial respiration. In vivo pyruvate administration during but not prior to neovessel formation (in line with mitochondrial activity time course) suppressed NV. Conclusions: Mitochondrial energetics were suppressed during retinal NV in OIR. Appropriately timed supplementation of pyruvate may be a novel approach in neovascular retinal diseases. [ABSTRACT FROM AUTHOR]

Aerobic glycolysis plays a pivotal role in the progression of tumors. Previously, a glycolysis‐associated prognostic model in CRC was constructed and the glycolysis‐related gene SPAG4 was discovered to be upregulated in CRC and was correlated with adverse prognosis. To date, however, no study has elucidated the specific role of SPAG4 in the development of CRC. In our study, CRC cells were transfected with si‐SPAG4 or OE‐SPAG4 to evaluate the influence of SPAG4 silencing or overexpression on CRC cell malignant behaviors. CRC cell proliferation and metastasis were detected via CCK‐8, colony formation, and Transwell assays. The oxygen consumption rate and extracellular acidification rate of CRC cells were determined by using an XF24 extracellular flux analyzer. The expression of SPAG4, key mitochondrial markers (NDUFA1, SDHB, ATP5A, and PGC‐1α), key enzymes involved in glycolysis (GLUT1, HK2, LDHA, PKM2, and PFK1), and PI3K/Akt pathway‐molecules and downstream transcription factor HIF‐1α was assessed by RT‐qPCR and western blot analysis. SPAG4 expression in CRC and normal tissue samples was tested through immunohistochemical staining. Finally, SPAG4‐overexpressed CRC cells were treated with LY294002 to validate the inhibition of PI3K/Akt pathway on CRC cell malignant phenotypes. Our results showed that SPAG4 was upregulated in CRC cells and tissues, and high expression SPAG4 predicted shorter overall survival time. SPAG4 knockdown inhibited while SPAG4 overexpression enhanced CRC cell proliferation, migration, invasion, mitochondrial respiration, and aerobic glycolysis. Overexpressing SPAG4 elevated p‐PI3K, p‐Akt, p‐mTOR, and HIF‐1α protein levels, which were restored after LY294002 treatment. Furthermore, LY294002 abolished the promotion of SPAG4 overexpression on CRC malignant phenotypes. Collectively, SPAG4 plays an oncogenic role in CRC by promoting mitochondrial respiration and aerobic glycolysis through activating the PI3K/Akt signaling. These findings suggest that inhibition of SPAG4‐mediated glucose metabolism may represent a potential strategy for the clinical treatment of CRC. [ABSTRACT FROM AUTHOR]

Phoenixin (PNX) is an emerging neuropeptide that plays a significant role in regulating metabolism and reproduction. This comprehensive review examines findings from human, in vivo, and in vitro studies to elucidate the functions of PNX in metabolic processes. PNX has been identified as a key player in essential metabolic pathways, including energy homeostasis, glucose, lipid and electrolyte metabolism, and mitochondrial dynamics. It modulates food and fluid intake, influences glucose and lipid profiles, and affects mitochondrial biogenesis and function. PNX is abundantly expressed in the hypothalamus, where it plays a crucial role in regulating reproductive hormone secretion and maintaining energy balance. Furthermore, PNX is also expressed in peripheral tissues such as the heart, spleen, and pancreas, indicating its involvement in the regulation of metabolism across central and peripheral systems. PNX is a therapeutic peptide that operates through the G protein-coupled receptor 173 (GPR173) at the molecular level. It activates signaling pathways such as cAMP-protein kinase A (PKA) and Epac-ERK, which are crucial for metabolic regulation. Research suggests that PNX may be effective in managing metabolic disorders like obesity and type 2 diabetes, as well as reproductive health issues like infertility. Since metabolic processes are closely linked to reproduction, further understanding of PNX’s role in these areas is necessary to develop effective management/treatments. This review aims to highlight PNX’s involvement in metabolism and identify gaps in current knowledge regarding its impact on human health. Understanding the mechanisms of PNX’s action is crucial for the development of novel therapeutic strategies for the treatment of metabolic disorders and reproductive health issues, which are significant public health concerns globally. [ABSTRACT FROM AUTHOR]

Microbes have evolved intricate communication systems that enable individual cells of a population to send and receive signals in response to changes in their immediate environment. In the fission yeast Schizosaccharomyces pombe, the oxylipin nitrogen signaling factor (NSF) is part of such communication system, which functions to regulate the usage of different nitrogen sources. Yet, the pathways and mechanisms by which NSF acts are poorly understood. Here, we show that NSF physically interacts with the mitochondrial sulfide:quinone oxidoreductase Hmt2 and that it prompts a change from a fermentation- to a respiration-like gene expression program without any change in the carbon source. Our results suggest that NSF activity is not restricted to nitrogen metabolism alone and that it could function as a rheostat to prepare a population of S. pombe cells for an imminent shortage of their preferred nutrients. Synopsis: Chemical cell-to-cell communication in the fission yeast Schizosaccharomyces pombe is essential for adaption to environmental changes in nutrient availability. This study uncovers that the extracellular signaling molecule nitrogen signaling factor (NSF) functions to counter nitrogen catabolite repression, and to switch from fermentation to respiratory metabolism. Nitrogen Signaling Factor (NSF) functions in an intra-species communication system of. With increasing cell density during population growth, NSF reaches a critical concentration that triggers a switch from a fermentation- to a respiration-like gene expression program. The putative 1-acyldihydroxyacetone phosphate reductase Ayr1 counteracts NSF signaling. The mitochondrial sulfide:quinone oxidoreductase Hmt2 is a direct and functionally relevant target of NSF. NSF is a transmissible signal that activates mitochondrial respiration to maximize growth. The oxylipin NSF is a transmissible signal that activates mitochondrial respiration to maximize growth. [ABSTRACT FROM AUTHOR]

High-resolution respirometry in human permeabilized muscle fibers is extensively used for analysis of mitochondrial adaptions to nutrition and exercise interventions, and is linked to athletic performance. However, the lack of standardization of experimental conditions limits quantitative inter- and intra-laboratory comparisons. In our study, an international team of investigators measured mitochondrial respiration of permeabilized muscle fibers obtained from three biopsies (vastus lateralis) from the same healthy volunteer to avoid inter-individual variability. High-resolution respirometry assays were performed together at the same laboratory to assess whether the heterogenity in published results are due to the effects of respiration media (MiR05 versus Z) with or without the myosin inhibitor blebbistatin at low- and high-oxygen regimes. Our findings reveal significant differences between respiration media for OXPHOS and ETcapacities supported by NADH&succinate-linked substrates at different oxygen concentrations. Respiratory capacities were approximately 1.5-fold higher in MiR05 at high-oxygen regimes compared to medium Z near air saturation. The presence or absence of blebbistatin in human permeabilized muscle fiber preparations was without effect on oxygen flux. Our study constitutes a basis to harmonize and establish optimum experimental conditions for respirometric studies of permeabilized human skeletal muscle fibers to improve reproducibility. [Display omitted] • Understanding muscle energetics' link to athletic performance is crucial. • Harmonizing mitochondrial bioenergetics protocols is critical for inter-study data analysis. • Medium composition and oxygen concentration influence muscle mitochondria respiratory capacity in permeabilized fibers. • Optimizing experimental protocols is pivotal for precise athletic performance evaluation. [ABSTRACT FROM AUTHOR]

Background: Influence on stem cells' angiogenesis and osteogenesis of NAD(P)H Quinone Dehydrogenase 1(NQO1) has been established, but its impact on dental pulp stem cells (DPSCs) is unexplored. An important strategy for the treatment of arteriosclerosis is to inhibit calcium deposition and to promote vascular repair and angiogenesis. This study investigated the function and mechanism of NQO1 on angiogenesis and osteogenesis of DPSCs, so as to provide a new ideal for the treatment of arteriosclerosis. Methods: Co-culture of human DPSCs and human umbilical vein endothelial cells (HUVECs) was used to detect the angiogenesis ability. Alkaline phosphatase (ALP) activity, alizarin red staining (ARS), and transplantation of HA/tricalcium phosphate with DPSCs were used to detect osteogenesis. Results: NQO1 suppressed in vitro tubule formation, migration, chemotaxis, and in vivo angiogenesis, as evidenced by reduced CD31 expression. It also enhanced ALP activity, ARS, DSPP expression and osteogenesis and boosted mitochondrial function in DPSCs. CoQ10, an electron transport chain activator, counteracted the effects of NQO1 knockdown on these processes. Additionally, NQO1 downregulated MAPK signaling, which was reversed by CoQ10 supplementation in DPSCs-NQO1sh. Conclusions: NQO1 inhibited angiogenesis and promoted the osteogenesis of DPSCs by suppressing MAPK signaling pathways and enhancing mitochondrial respiration. [ABSTRACT FROM AUTHOR]

P2X3-receptors localized in the hippocampus participate in the transmission of excitation and the formation of synaptic plasticity underlying learning and memory. P2X3-receptors are of great importance in the occurrence of neuropathic pain in epilepsy, acute and inflammatory pain of various genesis and localization as well as in the activation and growth of nerves after traumatic brain injury. The aim of the study was to study the elastic properties of the surface and the metabolic profile of neurons in an embryonic primary mixed hippocampal culture under P2X3-receptor blockade. The study was performed on a primary mixed culture of hippocampal neurons obtained from CD1 mice on the 18th day of gestation (E18). The highly selective blocker 5-(5-iodo-2-isopropyl-4-methoxyphenoxy)pyrimidine-2.4-diamine monochloride salt was selected as a P2X3-receptor blocker. To assess the elastic properties of neurons Young's modulus that characterizes the rigidity of the cell surface was measured. Measurements on an atomic force microscope applying a load in 25 local areas of the cell surface were performed. At each point, the force curves of the cantilever approach and retraction were recorded with subsequent calculation of Young's modulus. The metabolic profile of the neuroglial culture in Energy Phenotype test on a Seahorse HS mini cell metabolism analyzer (USA) was studied. The Young's modulus of the cell surface of neurons in the control was in the range from 6.8 ± 0.1 to 9.7 ± 0.2 kPa, and under the action of the P2X3-receptor blocker in the range from 3.1 ± 0.1 kPa to 8.5 ± 0.1 kPa. Under the conditions of P2X3-receptor blockade on the 5th day of differentiation the Young's modulus of the cell surface was reduced by 62% (p < 0.05), on the 8th day it increased by 22% (p < 0.05) and by the 11th day it decreased by 16.7% (p < 0.05) compared to the control. Aerobic respiration was characteristic of the embryonic hippocampal culture both in the control and with the P2X3-receptor blockade. Consequently, the blockade of the P2X3-receptor did not affect the metabolic profile of the E18 hippocampal culture. The obtained data indicate the direct participation of the P2X3-receptor in the formation of biomechanical properties of the cell surface in the processes of differentiation and signal transduction. It is possible, that the blockade of the P2X3-receptor will be one of the promising molecular targets that can reduce neuronal damage in brain injuries, neuroinflammation, hypoxia, and epilepsy. In addition, the study of the P2X3-receptor blockade can expand the fundamental understanding of the role of the purinergic signaling system in the formation of complex neuronal morphology at early stages of embryonic development under conditions of rapid excitatory signal transmission mediated by the ATP molecule. [ABSTRACT FROM AUTHOR]

The establishment of effective antiviral responses within host cells is intricately related to their metabolic status, shedding light on immunometabolism. In this study, we investigated the hypothesis that cellular reliance on glutamine metabolism contributes to the development of a potent antiviral response. We evaluated the antiviral response in the presence or absence of L-glutamine in the culture medium, revealing a bivalent response hinging on cellular metabolism. While certain interferon-stimulated genes (ISGs) exhibited higher expression in an oxidative phosphorylation (OXPHOS)-dependent manner, others were surprisingly upregulated in a glycolytic-dependent manner. This metabolic dichotomy was influenced in part by variations in interferon-β (IFN-β) expression. We initially demonstrated that the presence of L-glutamine induced an enhancement of OXPHOS in A549 cells. Furthermore, in cells either stimulated by poly:IC or infected with dengue virus and Zika virus, a marked increase in ISGs expression was observed in a dose-dependent manner with L-glutamine supplementation. Interestingly, our findings unveiled a metabolic dependency in the expression of specific ISGs. In particular, genes such as ISG54, ISG12 and ISG15 exhibited heightened expression in cells cultured with L-glutamine, corresponding to higher OXPHOS rates and IFN-β signaling. Conversely, the expression of viperin and 2′-5′-oligoadenylate synthetase 1 was inversely related to L-glutamine concentration, suggesting a glycolysis-dependent regulation, confirmed by inhibition experiments. This study highlights the intricate interplay between cellular metabolism, especially glutaminergic and glycolytic, and the establishment of the canonical antiviral response characterized by the expression of antiviral effectors, potentially paving the way for novel strategies to modulate antiviral responses through metabolic interventions. [ABSTRACT FROM AUTHOR]

Lower oxidative capacity in skeletal muscles (SKMs) is a prevailing cause of metabolic diseases. Exercise not only enhances the fatty acid oxidation (FAO) capacity of SKMs but also increases lactate levels. Given that lactate may contribute to tricarboxylic acid cycle (TCA) flux and impact monocarboxylate transporter 1 in the SKMs, we hypothesize that lactate can influence glucose and fatty acid (FA) metabolism. To test this hypothesis, we investigated the mechanism underlying lactate-driven FAO regulation in the SKM of mice with diet-induced obesity (DIO). Lactate was administered to DIO mice immediately after exercise for over 3 wk. We found that increased lactate levels enhanced energy expenditure mediated by fat metabolism during exercise recovery and decreased triglyceride levels in DIO mice SKMs. To determine the lactate-specific effects without exercise, we administered lactate to mice on a high-fat diet (HFD) for 8 wk. Similar to our exercise conditions, lactate increased FAO, TCA cycle activity, and mitochondrial respiration in the SKMs of HFD-fed mice. In addition, under sufficient FA conditions, lactate increased uncoupling protein-3 abundance via the NADH-NAD+ shuttle. Conversely, ATP synthase abundance decreased in the SKMs of HFD mice. Taken together, our results suggest that lactate amplifies the adaptive increase in FAO capacity mediated by the TCA cycle and mitochondrial respiration in SKMs under sufficient FA abundance. NEW & NOTEWORTHY: Lactate administration post-exercise promotes triglyceride content loss in skeletal muscles (SKMs) and reduced body weight. Lactate enhances fatty acid oxidation in the SKMs of high-fat diet (HFD)-fed mice due to enhanced mitochondrial oxygen consumption. In addition, lactate restores the malate-aspartate shuttle, which is reduced by a HFD, and activates the tricarboxylic acid cycle (TCA) cycle in SKMs. Interestingly, supraphysiological lactate facilitates uncoupling protein-3 expression through NADH/NAD+, which is enhanced under high-fat levels in SKMs. [ABSTRACT FROM AUTHOR]

To elucidate the possible biological roles of fatty acid-binding protein 5 (FABP5) in the intraocular environment, the cells from which FABP5 originates were determined by using four different intraocular tissue-derived cell types including human non-pigmented ciliary epithelium (HNPCE) cells, retinoblastoma (RB) cells, adult retinal pigment epithelial19 (ARPE19) cells and human ocular choroidal fibroblast (HOCF) cell lines, and the effects of FABP ligand 6, a specific inhibitor for FABP5 and FABP7 were analyzed by RNA sequencing and seahorse cellular metabolic measurements. Among these four different cell types, qPCR analysis showed that FABP5 was most prominently expressed in HNPCE cells, in which no mRNA expression of FABP7 was detected. In RNA sequencing analysis, 166 markedly up-regulated and 198 markedly down-regulated differentially expressed genes (DEGs) were detected between non-treated cells and cells treated with FABP ligand 6. IPA analysis of these DEGs suggested that FABP5 may be involved in essential roles required for cell development, cell survival and cell homeostasis. In support of this possibility, both mitochondrial and glycolytic functions of HNPCE cells, in which mRNA expression of FABP5, but not that of FABP7, was detected, were shown by using a Seahorse XFe96 Bioanalyzer to be dramatically suppressed by FABP ligand 6-induced inhibition of the activity of FABP5. Furthermore, in IPA upstream analysis, various unfolded protein response (UPR)-related factors were identified as upstream and causal network master regulators. Analysis by qPCR analysis showed significant upregulation of the mRNA expression of most of UPR-related factors and aquaporin1 (AQP1). The findings in this study suggest that HNPCE is one of intraocular cells producing FABP5 and may be involved in the maintenance of UPR and AQP1-related functions of HNPCE. [ABSTRACT FROM AUTHOR]

Mitochondrial transporters facilitate the translocation of metabolites between the cytoplasm and mitochondria and are critical for mitochondrial functional integrity. Although many mitochondrial transporters are associated with metabolic diseases, how they regulate mitochondrial function and their metabolic contributions at the cellular level are largely unknown. Here, we show that mitochondrial thiamine pyrophosphate (TPP) transporter SLC25A19 is required for mitochondrial respiration. SLC25A19 deficiency leads to reduced cell viability, increased integrated stress response (ISR), enhanced glycolysis and elevated cell sensitivity to 2-deoxyglucose (2-DG) treatment. Through a series of biochemical assays, we found that the depletion of mitochondrial NADH is the primary cause of the impaired mitochondrial respiration in SLC25A19 deficient cells. We also showed involvement of SLC25A19 in regulating the enzymatic activities of complexes I and III, the tricarboxylic acid (TCA) cycle, malate-aspartate shuttle and amino acid metabolism. Consistently, addition of idebenone, an analog of coenzyme Q10, restores mitochondrial respiration and cell viability in SLC25A19 deficient cells. Together, our findings provide new insight into the functions of SLC25A19 in mitochondrial and cellular physiology, and suggest that restoring mitochondrial respiration could be a novel strategy for treating SLC25A19-associated disorders. [Display omitted] • Loss of SLC25A19 leads to mitochondrial NADH depletion, thereby inhibiting mitochondrial respiration. • SLC25A19 is required for complex I and complex III enzyme activities. • Loss of SLC25A19 causes mitochondrial integrated stress response. • Idebenone rescues mitochondrial respiration in SLC25A19 deficient cells. [ABSTRACT FROM AUTHOR]

Maintenance of bone homeostasis and the balance between bone resorption and formation are crucial for maintaining skeletal integrity. This study sought to investigate the role of salt-inducible kinase 3 (SIK3), a key regulator in cellular energy metabolism, during the differentiation of osteoclasts. Despite osteoclasts being high energy-consuming cells essential for breaking down mineralized bone tissue, the specific function of SIK3 in this process remains unclear. To address this issue, we generated osteoclast-specific SIK3 conditional knockout mice and assessed the impact of SIK3 deletion on bone homeostasis. Our findings revealed that SIK3 conditional knockout mice exhibited increased bone mass and an osteopetrosis phenotype, suggesting a pivotal role for SIK3 in bone resorption. Moreover, we assessed the impact of pterosin B, a SIK3 inhibitor, on osteoclast differentiation. The treatment with pterosin B inhibited osteoclast differentiation, reduced the numbers of multinucleated osteoclasts, and suppressed resorption activity in vitro. Gene expression analysis demonstrated that SIK3 deletion and pterosin B treatment influence a common set of genes involved in osteoclast differentiation and bone resorption. Furthermore, pterosin B treatment altered intracellular metabolism, particularly affecting key metabolic pathways, such as the tricarboxylic acid cycle and oxidative phosphorylation. These results provide valuable insights into the involvement of SIK3 in osteoclast differentiation and the molecular mechanisms underlying osteoclast function and bone diseases. Lay Summary: Osteoporosis is a disease that causes bones to become weak and fragile, increasing the risk of fractures especially in elderly. It is caused by an imbalance between the formation of new bone and the destruction of old bone. Cells called osteoclasts are responsible for breaking down old bone. Excessive osteoclast activity results in bone loss and osteoporosis. Our research has identified a LKB1-SIK3 pathway, which acts as an energy sensor in osteoclasts. We found that this pathway is activated when osteoclast activity is increased, and we were able to reduce osteoclast activity by genetically removing or inhibiting SIK3. These findings suggest that targeting the LKB1-SIK3 pathway may be a promising new approach for the treatment of osteoporosis. Developing drugs that inhibit SIK3 may slow bone loss and reduce the risk of fractures in osteoporotic patients. Graphical Abstract [ABSTRACT FROM AUTHOR]

Angiogenesis is the determining factor during dental pulp regeneration. Six‐twelve leukemia (STL) is identified as a key regulatory factor on the biological function of dental pulp stem cells (DPSCs) under hypoxic conditions, but its effect on angiogenesis is unclear. Co‐culture of DPSCs and human umbilical vein endothelial cells (HUVECs) is used to detect tubule formation ability in vitro and the angiogenesis ability in vivo. RNA‐seq and bioinformatic analyses are performed to screen differentially expressed genes. Seahorse Cell Mito Stress Test is proceeded to exam mitochondrial respiration. STL decreased tubule formation and mitochondrial respiration of DPSCs in vitro and restrained the number of blood vessels and the expression of VEGF in new formed tissue in vivo. Furthermore, pretreating STL‐depleted DPSCs with rotenone, a mitochondrial respiration inhibitor, counteracted the promoting effect of STL knockdown on tubule formation. Then, RNA‐seq and bioinformatic analyses identified some angiogenesis relevant genes and pathways in STL‐depleted DPSCs. And STL enhanced expression of mRNA‐ring finger protein 217 (RNF217), which inhibited the tubule formation and mitochondrial respiration of DPSCs. STL inhibited the angiogenesis of DPSCs through depressing mitochondrial respiration by enhancing RNF217, indicating that STL is a potential target for angiogenesis of DPSCs. [ABSTRACT FROM AUTHOR]

Abstract SLC25A42 encodes the mitochondrial coenzyme A (CoA) transporter localized at the inner mitochondrial membrane. SLC25A42 deficiency leads to a congenital disease with a heterogeneous clinical presentation, including myopathy, developmental delay, lactic acidosis, and encephalopathy. Twenty‐one patients have been described so far. In the current study, we report on the identification of new biallelic variants in SLC25A42 in three siblings. Patients presented with symmetrical T2 hyperintensity of the putamen with minor volume depression at the brain MRI, elevated lactate, reduced oxygen consumption rates in muscle and fibroblasts, and reduced CoA levels in fibroblasts. Administration of pantothenic acid led to clinical stabilization and increased CoA levels in fibroblasts, thus confirming a role for SLC25A42 in energy metabolism and CoA homeostasis.

Background. Premature birth is the main cause of morbidity and mortality in the neonatal period, with long-term consequences for the child’s further psycho-physical development and health. Given the objective deterioration of the economic component and social instability during the hostilities in Ukraine, the birth rate is not expected to increase in the coming years. So, it is important to preserve the life and health of every newborn child. The well-being of the intrauterine environment and birth, morphological and functional maturity at birth are the basis for the child’s postnatal adaptation. Perinatal hypoxia is a predictor of significant metabolic disorders at the subcellular, cellular, organ and systemic levels. This results in impaired adaptation in the neonatal period and a high risk of developing functional and chronic pathology in the future. The purpose of the study is to examine the features of intracellular energy exchange in perinatal pathology in preterm infants. This will facilitate the investigation of the underlying pathophysiological mechanisms of severe forms of diseases and provide justification for the introduction of additional laboratory markers of hypoxic inflammation in practical neonatology. Materials and methods. A clinical and laboratory examination was conducted on 68 preterm infants with a gestational age of 32–33/6 weeks who exhibited severe forms of perinatal pathology. The comparison group comprised 27 conditionally healthy children with a gestational age at birth of 34–36/6 weeks. The inclusion criteria were a gestational age at birth of 32–33/6 weeks and severe perinatal pathology. The exclusion criteria were as follows: a gestational age at birth of less than 32 weeks or above 37 weeks, congenital malformations, and neonatal sepsis. In addition to the conventional methods of clinical and laboratory examination of newborns, indicators of intracellular energy exchange were determined: glycerol-3-phosphate dehydrogenase (GPDH) (EC 1.1.99.5), succinate dehydrogenase (SDH) (EC 1.3.99.1) and NADH (nicotinamide adenine dinucleotide, reduced form) dehydrogenase (EC 1.6.5.3) in lymphocytes, lactate, pyruvate and the lactate/pyruvate ratio in blood serum. The values of SDH, GPDH and NADH were employed in order to calculate the aerobic respiration (AR) rate and electron transport chain (ETC) coefficient. The statistical processing of the study results was conducted using the software package Statistica (StatSoft Inc., USA, version 10). A Student’s t-test was employed for the comparison of quantitative indicators with normal distribution, at a significance level of p < 0.05 and p < 0.001. The qualitative diffe­rences between the comparison groups were assessed with the MedCalc software package (Statistical Software Package for Biomedical Research, 2023, version 16.1). Results. The findings demonstrated significant alterations in energy exchange in preterm infants subjected to hypoxic conditions in the context of severe perinatal pathology. In particular, a reduction in pyruvate levels accompanied by an increase in the lactate/pyruvate ratio suggests an insufficient energy exchange and the dominance of anaerobic glycolysis. Additionally, alterations in the activity of mitochondrial respiratory chain enzymes, including a decline in GPDH, an increase in SDH, a decrease in NADH, and a reduction in the AR rate accompanied by an increase in the ETC coefficient, were observed. The results of statistical receiver operating characteristic analysis of the laboratory indicators of energy exchange demonstrated a satisfactory level of sensitivity and specificity suggesting the potential utility of these parameters in perinatal pathology in preterm infants. Conclusions. The use of laboratory indicators of energy exchange, along with the conventional methods for additional paraclinical examination, will facilitate the prompt rectification of therapeutic measures, thereby enhancing the efficacy of medical care for preterm infants. This is achieved by the realignment of oxygen therapy measures at the intensive care stage. Furthermore, it provides a scientific foundation for the search for pharmacotherapeutic agents to control mitochondrial respiration disorders in conditions of hypoxic damage to the body.

Abstract Background Influence on stem cells’ angiogenesis and osteogenesis of NAD(P)H Quinone Dehydrogenase 1(NQO1) has been established, but its impact on dental pulp stem cells (DPSCs) is unexplored. An important strategy for the treatment of arteriosclerosis is to inhibit calcium deposition and to promote vascular repair and angiogenesis. This study investigated the function and mechanism of NQO1 on angiogenesis and osteogenesis of DPSCs, so as to provide a new ideal for the treatment of arteriosclerosis. Methods Co-culture of human DPSCs and human umbilical vein endothelial cells (HUVECs) was used to detect the angiogenesis ability. Alkaline phosphatase (ALP) activity, alizarin red staining (ARS), and transplantation of HA/tricalcium phosphate with DPSCs were used to detect osteogenesis. Results NQO1 suppressed in vitro tubule formation, migration, chemotaxis, and in vivo angiogenesis, as evidenced by reduced CD31 expression. It also enhanced ALP activity, ARS, DSPP expression and osteogenesis and boosted mitochondrial function in DPSCs. CoQ10, an electron transport chain activator, counteracted the effects of NQO1 knockdown on these processes. Additionally, NQO1 downregulated MAPK signaling, which was reversed by CoQ10 supplementation in DPSCs-NQO1sh. Conclusions NQO1 inhibited angiogenesis and promoted the osteogenesis of DPSCs by suppressing MAPK signaling pathways and enhancing mitochondrial respiration.

Abstract Background Chemoresistance remains a significant challenge in colorectal cancer (CRC) treatment, necessitating a deeper understanding of its underlying mechanisms. HOXC11 has emerged as a potential regulator in various cancers, but its role in CRC chemoresistance remains unclear. Methods Sulforhodamine B assay was employed to assess the cell viability of CRC cells following treatment with chemotherapeutic drugs. Immunofluorescence staining was performed to examine the subcellular localization of HOXC11 in normal and chemoresistant CRC cells. The Seahorse mito stress test was conducted to evaluate the mitochondrial respiratory function of CRC cells. Real-time PCR was utilized to measure the expression level and copy number of mitochondrial DNA (mtDNA). Results Our findings revealed that HOXC11 was overexpressed in CRC cells compared to normal colorectal cells and correlated with poorer prognosis in CRC patients. Knockout of HOXC11 reversed acquired chemoresistance in CRC cells. Furthermore, we observed a functional subset of HOXC11 localized to the mitochondria in chemoresistant CRC cells, which regulated mitochondrial function by modulating mtDNA transcription, thereby affecting chemoresistance. Conclusions In summary, our study reveals that HOXC11 regulates mitochondrial function through the modulation of mtDNA transcription, impacting chemoresistance in colorectal cancer cells. These findings underscore the significance of understanding the molecular mechanisms underlying chemoresistance and highlight the potential therapeutic implications of targeting mitochondrial function in CRC treatment.

Abstract Background Diabetic foot ulcer (DFU) is the most devastating complication of diabetes mellitus (DM) and plays a major role in disability and death in DM patients. NADH: ubiquinone oxidoreductase subunit B5 (NDUFB5) plays an important role in maintaining mitochondrial respiration, but whether it is involved in regulating the progression of advanced glycation end products (AGEs)-mediated DFU is still unclear. Methods Firstly, the role of AGEs on cell viability, migration, and mitochondrial respiration in human umbilical vein endothelial cells (HUVECs) was explored in vitro. Next, NDUFB5 expression was detected in human samples and AGEs-treated HUVECs, and NDUFB5’s effect on AGEs-induced HUVECs injury and skin wound in diabetic mice was further clarified. In addition, the role of m6A modification mediated by methyltransferase-like 3 (METTL3) in regulating NDUFB5 expression and AGEs-induced HUVECs injury was investigated. Results NDUFB5 promoted cell viability, migration, and mitochondrial respiration in AGEs-treated HUVECs, whereas mitochondrial fusion promoter M1 facilitated cell viability, migration, and mitochondrial oxiadative respiration in NDUFB5 knockdown HUVECs. Meanwhile, NDUFB5 promotes skin wound healing in diabetic mice. Besides, METTL3-mediated m6A modification and insulin like growth factor 2 mRNA binding protein 2 (IGF2BP2) enhanced NDUFB5 expression in HUVECs. Furthermore, METTL3 promoted cell viability, migration, and mitochondrial respiration in AGEs-treated HUVECs by increasing NDUFB5. Conclusion METTL3-mediated NDUFB5 m6A modification inhibits AGEs-induced cell injury in HUVECs. METTL3 and NDUFB5 might serve as potential targets for DFU therapy in the future.

Abstract Aims The conditions of hypoxia are suggested to induce permanent atrial fibrillation (AF). The regulation of COX4I2 and COX4I1 depends on oxygen availability in tissues. A role of COX4I2 in the myocardium of AF patients is supposed for pathogenesis of AF and subsequent alterations in the electron transfer chain (ETC) under hypoxia. Methods and results In vitro, influence of hypoxia on HeLa 53 cells was studied and elevated parts of COX 4I2 were confirmed. Myocardial biopsies were taken ex vivo from the patients' Right Atria with SR (n = 31) and AF (n = 11), respectively. RT‐ PCR for mRNA expresson, mitochondrial respiration by polarography and the protein content of cytochrome c oxidase (CytOx) subunit 4I1 and CytOx subunit 4I2 by ELISA were studied. Clinical data were correlated to the findings of gene expressions in parallel. Patients with permanent AF had a change in isoform 4I2/4I1 expression along with a decrease of isoform COX 4I1 expression. The 4I2/4I1 ratio of mRNA expression was increased from 0.630 to 1.058 in comparison. However, the protein content of CytOx subunit 4 was much lower in the AF group, whereas the respiration/units enzyme activity in both groups remained the same. Conclusions This study describes a possible molecular correlate for the development of AF. Due to the known functional significance of COX 4I2, mitochondrial dysfunction can be assumed as a part of the pathogenesis of AF.

Autism spectrum disorder (ASD) is a multifactorial neurodevelopmental condition with several identified risk factors, both genetic and non-genetic. Among these, prenatal exposure to valproic acid (VPA) has been extensively associated with the development of the disorder. The zebrafish, a cost- and time-effective model, is useful for studying ASD features. Using validated VPA-induced ASD zebrafish models, we aimed to provide new insights into VPA exposure effects during embryonic development and to identify new potential biomarkers associated with ASD-like features. Dose–response analyses were performed in vivo to study larval phenotypes and mechanisms underlying neuroinflammation, mitochondrial dysfunction, oxidative stress, microglial cell status, and motor behaviour. Wild-type and transgenic Tg(mpeg1:EGFP) zebrafish were water-exposed to VPA doses (5 to 500 µM) from 6 to 120 h post-fertilisation (hpf). Embryos and larvae were monitored daily to assess survival and hatching rates, and numerous analyses and tests were conducted from 24 to 120 hpf. VPA doses higher than 50 µM worsened survival and hatching rates, while doses of 25 µM or more altered morphology, microglial status, and larval behaviours. VPA 50 µM also affected mRNA expression of inflammatory cytokines and neurogenesis-related genes, mitochondrial respiration, and reactive oxygen species accumulation. The study confirmed that VPA alters brain homeostasis, synaptic interconnections, and neurogenesis-related signalling pathways, contributing to ASD aetiopathogenesis. Further studies are essential to identify novel ASD biomarkers for developing new drug targets and tailored therapeutic interventions for ASD. [ABSTRACT FROM AUTHOR]

Aim: Alzheimer's disease (AD) is the most common form of dementia. However, while 150+ animal models of AD exist, drug translation from preclinical models to humans for treatment usually fails. One factor contributing to low translation is likely the absence of neurodegenerative models that also encompass the multi‐morbidities of human aging. We previously demonstrated that, in comparison to the PigmEnTed (PET) guinea pig strain which models "typical" brain aging, the Hartley strain develops hallmarks of AD like aging humans. Hartleys also exhibit age‐related impairments in cartilage and skeletal muscle. Impaired mitochondrial respiration is one driver of both cellular aging and AD. In humans with cognitive decline, diminished skeletal muscle and brain respiratory control occurs in parallel. We previously reported age‐related declines in skeletal muscle mitochondrial respiration in Hartleys. It is unknown if there is concomitant mitochondrial dysfunction in the brain. Methods: Therefore, we assessed hippocampal mitochondrial respiration in 5‐ and 12‐month Hartley and PET guinea pigs using high‐resolution respirometry. Results: At 12 months, PETs had higher complex I supported mitochondrial respiration paralleling their increase in body mass compared to 5 months PETs. Hartleys were also heavier at 12 months compared to 5 months but did not have higher complex I respiration. Compared to 5 months Hartleys, 12 months Hartleys had lower complex I mitochondrial efficiency and compensatory increases in mitochondrial proteins collectively suggesting mitochondrial dysfunction with age. Conclusions: Therefore, Hartleys might be a relevant model to test promising therapies targeting mitochondria to slow brain aging and AD progression. [ABSTRACT FROM AUTHOR]

OBJECTIVES: Quantify the relationship between perioperative anaerobic lactate production, microcirculatory blood flow, and mitochondrial respiration in patients after cardiovascular surgery with cardiopulmonary bypass. DESIGN: Serial measurements of lactate-pyruvate ratio (LPR), microcirculatory blood flow, plasma tricarboxylic acid cycle cycle intermediates, and mitochondrial respiration were compared between patients with a normal peak lactate (≤ 2 mmol/L) and a high peak lactate (≥ 4 mmol/L) in the first 6 hours after surgery. Regression analysis was performed to quantify the relationship between clinically relevant hemodynamic variables, lactate, LPR, and microcirculatory blood flow. SETTING: This was a single-center, prospective observational study conducted in an academic cardiovascular ICU. PATIENTS: One hundred thirty-two patients undergoing elective cardiovascular surgery with cardiopulmonary bypass. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patients with a high postoperative lactate were found to have a higher LPR compared with patients with a normal postoperative lactate (14.4 ± 2.5 vs. 11.7 ± 3.4; p = 0.005). Linear regression analysis found a significant, negative relationship between LPR and microcirculatory flow index (r = --0.225; β = --0.037; p = 0.001 and proportion of perfused vessels: r = --0.17; β = --0.468; p = 0.009). There was not a significant relationship between absolute plasma lactate and microcirculation variables. Last, mitochondrial complex I and complex II oxidative phosphorylation were reduced in patients with high postoperative lactate levels compared with patients with normal lactate (22.6 ± 6.2 vs. 14.5 ± 7.4 pmol O2/s/106 cells; p = 0.002). CONCLUSIONS: Increased anaerobic lactate production, estimated by LPR, has a negative relationship with microcirculatory blood flow after cardiovascular surgery. This relationship does not persist when measuring lactate alone. In addition, decreased mitochondrial respiration is associated with increased lactate after cardiovascular surgery. These findings suggest that high lactate levels after cardiovascular surgery, even in the setting of normal hemodynamics, are not simply a type B phenomenon as previously suggested. [ABSTRACT FROM AUTHOR]

Studies have shown that EMT (epithelial-mesenchymal transition) and energy metabolism influence each other, and it is unclear whether the trophoblast energy metabolism phenotype is dominated by glycolysis or mitochondrial respiration, and the relationship between trophoblast energy metabolism and EMT is still unclear. Exosomes were isolated from the DSC of URSA patients and their miRNA profile was characterized by miRNA sequencing. Wound healing assays and transwell assays were used to assess the invasion and migration ability of trophoblasts. Mitochondrial stress and glycolysis stress test were used to evaluate energy metabolism phenotype of trophoblast. Luciferase reporter assays, qRT-PCR and WB were conducted to uncover the underlying mechanism. Finally, animal experiments were employed to explore the effect of DSC-exos on embryo absorption in mice. Our results showed that URSA-DSC-exos suppressed trophoblast EMT to reduce their migration and invasion, miR-22-5p_R-1 was the most upregulated miRNAs. URSA-DSC-exos can suppress trophoblast MGS (metabolic switch from mitochondrial respiration to glycolysis) and inhibit trophoblast migration and invasion by transferring miR-22-5p_R-1. Mechanistically, miR-22-5p_R-1 suppress trophoblast MGS and inhibit trophoblast EMT by directly suppressing PDK4 expression at the post-transcriptional level. Furthermore, in vivo experiment suggested that URSA-DSC-exos aggravated embryo absorption in mice. Clinically, PDK4 and EMT molecule were aberrant in villous of URSA patients, and negative correlations were found between miR-22-5p_R-1 and PDK4. Our findings indicated that URSA-DSC-exos induced MGS obstacle playing an important role in intercellular communication between trophoblast and DSC, illuminating a novel mechanism in DSC regulation of trophoblasts and their role in URSA. • MiR-22-5p_R-1 was the most upregulated miRNAs in URSA-DSC-exos. • URSA-DSC-exos can transmit miR-22-5p_R-1 to trophoblasts which targeted PDK4. • Metabolism reprogramming plays an important role in regulating trophoblast EMT. • PDK4 is a key molecule that regulates the trophoblast's MGS and induce EMT. • Low expression of PDK4 inhibited the trophoblast EMT in URSA patients. [ABSTRACT FROM AUTHOR]

Background: Chemoresistance remains a significant challenge in colorectal cancer (CRC) treatment, necessitating a deeper understanding of its underlying mechanisms. HOXC11 has emerged as a potential regulator in various cancers, but its role in CRC chemoresistance remains unclear. Methods: Sulforhodamine B assay was employed to assess the cell viability of CRC cells following treatment with chemotherapeutic drugs. Immunofluorescence staining was performed to examine the subcellular localization of HOXC11 in normal and chemoresistant CRC cells. The Seahorse mito stress test was conducted to evaluate the mitochondrial respiratory function of CRC cells. Real-time PCR was utilized to measure the expression level and copy number of mitochondrial DNA (mtDNA). Results: Our findings revealed that HOXC11 was overexpressed in CRC cells compared to normal colorectal cells and correlated with poorer prognosis in CRC patients. Knockout of HOXC11 reversed acquired chemoresistance in CRC cells. Furthermore, we observed a functional subset of HOXC11 localized to the mitochondria in chemoresistant CRC cells, which regulated mitochondrial function by modulating mtDNA transcription, thereby affecting chemoresistance. Conclusions: In summary, our study reveals that HOXC11 regulates mitochondrial function through the modulation of mtDNA transcription, impacting chemoresistance in colorectal cancer cells. These findings underscore the significance of understanding the molecular mechanisms underlying chemoresistance and highlight the potential therapeutic implications of targeting mitochondrial function in CRC treatment. [ABSTRACT FROM AUTHOR]

While BCR::ABL1 tyrosine kinase inhibitors have transformed the treatment paradigm for chronic myeloid leukemia (CML), disease progression and treatment resistance due to BCR::ABL1-dependent and BCR::ABL1-independent mechanisms remain a therapeutic challenge. Natural compounds derived from plants have significantly contributed to cancer pharmacotherapy. This study investigated the efficacy of an active component of Leea indica, a local medicinal plant, in CML. Using high-performance liquid chromatography–electrospray ionization–mass spectrometry, a chemical constituent from L. indica extract was isolated and identified as gallic acid. Commercially obtained gallic acid was used as a chemical standard. Gallic acid from L. indica inhibited proliferation and induced apoptosis in CML cell lines, as did the chemical standard. Furthermore, gallic acid induced apoptosis and decreased the colony formation of primary CML CD34+ cells. The combination of isolated gallic acid or its chemical standard with BCR::ABL1 tyrosine kinase inhibitors resulted in a significantly greater inhibition of colony formation and cell growth compared to a single drug alone. Mechanistically, CML cells treated with gallic acid exhibited the disruption of multiple oncogenic pathways including ERK/MAPK, FLT3 and JAK/STAT, as well as impaired mitochondrial respiration. Rescue studies showed that gallic acid is significantly less effective in inducing apoptosis in mitochondrial respiration-deficient ρ0 cells compared to wildtype cells, suggesting that the action of gallic acid is largely through the inhibition of mitochondrial respiration. Our findings highlight the therapeutic potential of L. indica in CML and suggest that gallic acid may be a promising lead chemical constituent for further development for CML treatment. [ABSTRACT FROM AUTHOR]

Circadian oscillations of several physiological and behavioral processes are an established process in all the organisms anticipating the geophysical changes recurring during the day. The time-keeping mechanism is controlled by a transcription translation feedback loop involving a set of well-characterized transcription factors. The synchronization of cells, controlled at the organismal level by a brain central clock, can be mimicked in vitro, pointing to the notion that all the cells are endowed with an autonomous time-keeping system. Metabolism undergoes circadian control, including the mitochondrial terminal catabolic pathways, culminating under aerobic conditions in the electron transfer to oxygen through the respiratory chain coupled to the ATP synthesis according to the oxidative phosphorylation chemiosmotic mechanism. In this study, we expanded upon previous isolated observations by utilizing multiple cell types, employing various synchronization protocols and different methodologies to measure mitochondrial oxygen consumption rates under conditions simulating various metabolic stressors. The results obtained clearly demonstrate that mitochondrial respiratory activity undergoes rhythmic oscillations in all tested cell types, regardless of their individual respiratory proficiency, indicating a phenomenon that can be generalized. However, notably, while primary cell types exhibited similar rhythmic respiratory profiles, cancer-derived cell lines displayed highly heterogeneous rhythmic changes. This observation confirms on the one hand the dysregulation of the circadian control of the oxidative metabolism observed in cancer, likely contributing to its development, and on the other hand underscores the necessity of personalized chronotherapy, which necessitates a detailed characterization of the cancer chronotype. [ABSTRACT FROM AUTHOR]

Background: Diabetic foot ulcer (DFU) is the most devastating complication of diabetes mellitus (DM) and plays a major role in disability and death in DM patients. NADH: ubiquinone oxidoreductase subunit B5 (NDUFB5) plays an important role in maintaining mitochondrial respiration, but whether it is involved in regulating the progression of advanced glycation end products (AGEs)-mediated DFU is still unclear. Methods: Firstly, the role of AGEs on cell viability, migration, and mitochondrial respiration in human umbilical vein endothelial cells (HUVECs) was explored in vitro. Next, NDUFB5 expression was detected in human samples and AGEs-treated HUVECs, and NDUFB5's effect on AGEs-induced HUVECs injury and skin wound in diabetic mice was further clarified. In addition, the role of m6A modification mediated by methyltransferase-like 3 (METTL3) in regulating NDUFB5 expression and AGEs-induced HUVECs injury was investigated. Results: NDUFB5 promoted cell viability, migration, and mitochondrial respiration in AGEs-treated HUVECs, whereas mitochondrial fusion promoter M1 facilitated cell viability, migration, and mitochondrial oxiadative respiration in NDUFB5 knockdown HUVECs. Meanwhile, NDUFB5 promotes skin wound healing in diabetic mice. Besides, METTL3-mediated m6A modification and insulin like growth factor 2 mRNA binding protein 2 (IGF2BP2) enhanced NDUFB5 expression in HUVECs. Furthermore, METTL3 promoted cell viability, migration, and mitochondrial respiration in AGEs-treated HUVECs by increasing NDUFB5. Conclusion: METTL3-mediated NDUFB5 m6A modification inhibits AGEs-induced cell injury in HUVECs. METTL3 and NDUFB5 might serve as potential targets for DFU therapy in the future. [ABSTRACT FROM AUTHOR]

Background/Aims: Individual resistance to hypoxia is an important feature of the physiological profile of an organism, particularly in relation to lead-induced toxicity. Methods: Our study focused on evaluating parameters of mitochondrial oxygen consumption, microsomal oxidation, intensity of lipoperoxidation processes and antioxidant defences in the liver of rats with low (LR) and high (HR) resistance to hypoxia to elucidate the mechanisms of action of L-arginine and the NO synthase inhibitor L-NNA before or after exposure to lead nitrate. Results: Our study suggests that the redistribution of oxygen-dependent processes towards mitochondrial processes under the influence of the nitric oxide precursor amino acid L-arginine is an important mechanism for maintaining mitochondrial respiratory chain function during per os lead nitrate exposure (3.6 mg lead nitrate/kg bw per day for 30 days). Animals were given L-arginine at a dose of 600 mg/kg bw (i.p., 30 min) before and after exposure to lead nitrate or the NO synthase inhibitor Nω-nitro-L-arginine (L-NNA) at a dose of 35 mg/kg bw (i.p., 30 min) before and after exposure to lead nitrate. Our experiments demonstrated the efficacy of using lead nitrate to simulate lead-related toxic processes via Pb levels in liver tissue; we demonstrated significantly reduced levels of nitrites and nitrates, i.e. stable metabolites of the nitric oxide system, in both LR and HR animals. The effect of the amino acid L-arginine stabilised the negative effects of lead nitrate exposure in both groups of LR and HR rats. We observed the efficiency of mitochondrial energy supply processes and showed a greater vulnerability of NADH-dependent oxidation during lead nitrate exposure in the liver of HR rats. Conclusions: L-arginine initiated the processes of oxidation of NADH-dependent substrates in the LR group, whereas in the HR group this directionality of processes was more effective when the role of the nitric oxide system was reduced (use of L-NNA). Our study of key antioxidant enzyme activities in rat liver tissue during lead nitrate exposure revealed changes in the catalase-peroxidase activity ratio. We found different activities of antioxidant enzymes in the liver tissue of rats treated with lead nitrate and L-arginine or L-NNA, with a significant increase in GPx activity in the LR group when L-arginine was administered both before and after exposure to lead nitrate. [ABSTRACT FROM AUTHOR]

Objective: Glioma is a leading cause of mortality worldwide, its recurrence poses a major challenge in achieving effective treatment outcomes. Cancer stem cells (CSCs) have emerged as key contributors to tumor relapse and chemotherapy resistance, making them attractive targets for glioma cancer therapy. This study investigated the potential of FERMT1 as a prognostic biomarker and its role in regulating stemness through cell cycle in glioma. Methods: Using data from TCGA-GBM, GSE4290, GSE50161 and GSE147352 for analysis of FERMT1 expression in glioma tissues. Then, the effects of FERMT1 knockdown on cell cycle, proliferation, sphere formation ability, invasion and migration were investigated. The influences of FERMT1 on expression of glycolysis-related proteins and levels of ATP, glucose, lactate and G6PDH were also explored. Furthermore, the effects of FERMT1 knockdown on cellular metabolism were evidenced. Results: Significant upregulation of FERMT1 in glioma tissues was observed. Silencing FERMT1 not only affected the cell cycle but also led to a notable reduction in proliferation, invasion and migration. The expression of glycolysis-associated proteins including GLUT1, GLUT3, GLUT4, and SCO2 were reduced by FERMT1 knockdown, resulted in increased ATP and glucose as well as decreased lactic acid and G6PDH levels. FERMT1 knockdown also inhibited cellular metabolism. Moreover, FERMT1 knockdown significantly reduced sphere diameter, along with inhibiting the expression of transcription factors associated with stemness in glioma cells. Conclusion: These findings demonstrated that FERMT1 could be an ideal target for the advancement of innovative strategies against glioma treatment via modulating cellular process involved in stemness regulation and metabolism. [ABSTRACT FROM AUTHOR]

In several mammalian species, the measurement of mitochondrial oxygen consumption (MITOX) under different metabolic conditions has demonstrated a positive correlation with sperm motility and may be a sensitive indicator of mitochondrial health. In general, the maintenance of sperm motility and many key sperm functions and fertilizing events are heavily energy‐dependent processes, and some species‐specific substrate preferences exist. Although canine sperm have been known to undergo capacitation and maintain motility with supplementation of a wide range of energy substrates, the relationship between mitochondrial function, and the maintenance of oxidative metabolism and sperm motility remain unclear. The objective of this study was to explore the metabolic flexibility of canine sperm, and to investigate the relationship between mitochondrial function, and maintenance of motility under differing nutrient conditions. We explored substrate preferences and the bioenergetics underlying maintenance of canine sperm motility by monitoring mitochondrial oxidative function and sperm kinematics in the presence of mitochondrial effector drug treatments: FCCP, antimycin (ANTI), and oligomycin (OLIGO). We hypothesized that canine sperm possess the ability to use compensatory pathways and utilize diverse nutrient sources in the maintenance of motility. Oxygen consumption (change in pO2, oxygen partial pressure) and sperm kinematics (CASA) were measured concurrently (t0–t30) to assess the relationship between oxidative metabolism and maintenance of sperm motility in dogs. Four media were tested: containing glucose, lactate, and pyruvate (GLP), containing glucose (G), fructose (F), or lactate and pyruvate (LP). In the absence of pharmacological inhibition of the electron transport chain, energetic substrate had no effect on sperm kinematics in fertile dogs. Following mitochondrial disruption by ANTI and OLIGO, mitochondrial oxygen consumption was negatively correlated with several sperm motility parameters in GLP, G, F, and LP media. In every media, FCCP treatment quickly induced significantly higher oxygen consumption than in untreated sperm, and spare respiratory capacity, the maximal inducible oxidative metabolism, was high. With respiratory control ratios RCR >1 there was no indication of bioenergetic dysfunction in any media type, indicating that sperm mitochondria of fertile dogs have a high capacity for substrate oxidation and ATP turnover regardless of substrate. Our results suggest MITOX assessment is a valuable tool for assessing mitochondrial functionality, and that canine sperm employ flexible energy management systems which may be exploited to improve sperm handling and storage. [ABSTRACT FROM AUTHOR]

Inflammation, oxidative stress, and mitochondrial function are implicated in the development of obesity and its comorbidities. The purpose of this study was to assess the impact of weight loss through calorie restriction on the metabolic profile, inflammatory and oxidative stress parameters, and mitochondrial respiration in an obese population. A total of 109 subjects underwent two cycles of a very low-calorie diet alternated with a low-calorie diet (24 weeks). We analyzed biochemical and inflammatory parameters in serum, as well as oxidative stress markers, mRNA antioxidant gene expression, and mitochondrial respiration in peripheral blood mononuclear cells (PBMCs). After the intervention, there was an improvement in both insulin resistance and lipid profiles, including cholesterol subfractions. Weight loss produced a significant reduction in mitochondrial ROSs content and an increase in glutathione levels, coupled with an enhancement in the mRNA expression of antioxidant systems (SOD1, GSR, and CAT). In addition, a significant improvement in basal oxygen consumption, maximal respiration, and ATP production was observed. These findings demonstrate that moderate weight loss can improve insulin resistance, lipid profiles and subfractions, inflammatory and oxidative stress parameters, and mitochondrial respiration. Therefore, we can affirm that dietary intervention can simultaneously achieve significant weight loss and improve metabolic profile and mitochondrial function in obesity. [ABSTRACT FROM AUTHOR]

While cytostatic chemotherapy targeting DNA is known to induce genotoxicity, leading to cell cycle arrest and cytokine secretion, the impact of these drugs on fibroblast–epithelial cancer cell communication and metabolism remains understudied. Our research focused on human breast fibroblast RMF-621 exposed to nonlethal concentrations of cisplatin and doxorubicin, revealing reduced proliferation, diminished basal and maximal mitochondrial respirations, heightened mitochondrial ROS and lactate production, and elevated MCT4 protein levels. Interestingly, RMF-621 cells enhanced glucose uptake, promoting lactate export. Breast cancer cells MCF-7 exposed to conditioned media (CM) from drug-treated stromal RMF-621 cells increased MCT1 protein levels, lactate-driven mitochondrial respiration, and a significantly high mitochondrial spare capacity for lactate. These changes occurred alongside altered mitochondrial respiration, mitochondrial membrane potential, and superoxide levels. Furthermore, CM with doxorubicin and cisplatin increased migratory capacity in MCF-7 cells, which was inhibited by MCT1 (BAY-8002), glutamate dehydrogenase (EGCG), mitochondrial pyruvate carrier (UK5099), and complex I (rotenone) inhibitors. A similar behavior was observed in T47-D and ZR-75-1 breast cancer cells. This suggests that CM induces metabolic rewiring involving elevated lactate uptake to sustain mitochondrial bioenergetics during migration. Treatment with the mitochondrial-targeting antioxidant mitoTEMPO in RMF-621 and the addition of an anti-CCL2 antibody in the CM prevented the promigratory MCF-7 phenotype. Similar effects were observed in THP1 monocyte cells, where CM increased monocyte recruitment. We propose that nonlethal concentrations of DNA-damaging drugs induce changes in the cellular environment favoring a promalignant state dependent on mitochondrial bioenergetics. [ABSTRACT FROM AUTHOR]

Mitochondria harbor the oxidative phosphorylation (OXPHOS) system to sustain cellular respiration. However, the transcriptional regulation of OXPHOS remains largely unexplored. Through the cancer genome atlas (TCGA) transcriptome analysis, transcription factor THAP domain-containing 3 (THAP3) was found to be strongly associated with OXPHOS gene expression. Mechanistically, THAP3 recruited the histone methyltransferase SET and MYND domain-containing protein 3 (SMYD3) to upregulate H3K4me3 and promote OXPHOS gene expression. The levels of THAP3 and SMYD3 were altered by metabolic cues. They collaboratively supported liver cancer cell proliferation and colony formation. In clinical human liver cancer, both of them were overexpressed. THAP3 positively correlated with OXPHOS gene expression. Together, THAP3 cooperates with SMYD3 to epigenetically upregulate cellular respiration and liver cancer cell proliferation. [ABSTRACT FROM AUTHOR]

The purpose of the current study was to elucidate the physiological roles of intraocularly present fatty acid-binding protein 4 (FABP4). Using four representative intraocular tissue-derived cell types, including human non-pigmented ciliary epithelium (HNPCE) cells, retinoblastoma (RB) cells, adult retinal pigment epithelial19 (ARPE19) cells and human ocular choroidal fibroblast (HOCF) cells, the intraocular origins of FABP4 were determined by qPCR analysis, and the intracellular functions of FABP4 were investigated by seahorse cellular metabolic measurements and RNA sequencing analysis using a specific inhibitor for FABP4, BMS309403. Among these four different cell types, FABP4 was exclusively expressed in HOCF cells. In HOCF cells, both mitochondrial and glycolytic functions were significantly decreased to trace levels by BMS309403 in a dose-dependent manner. In the RNA sequencing analysis, 67 substantially up-regulated and 94 significantly down-regulated differentially expressed genes (DEGs) were identified in HOCF cells treated with BMS309403 and those not treated with BMS309403. The results of Gene Ontology enrichment analysis and ingenuity pathway analysis (IPA) revealed that the DEGs were most likely involved in G-alpha (i) signaling, cAMP-response element-binding protein (CREB) signaling in neurons, the S100 family signaling pathway, visual phototransduction and adrenergic receptor signaling. Furthermore, upstream analysis using IPA suggested that NKX2-1 (thyroid transcription factor1), HOXA10 (homeobox A10), GATA2 (gata2 protein), and CCAAT enhancer-binding protein A (CEBPA) were upstream regulators and that NKX homeobox-1 (NKX2-1), SFRP1 (Secreted frizzled-related protein 1) and TREM2 (triggering receptor expressed on myeloid cells 2) were causal network master regulators. The findings in this study suggest that intraocularly present FABP4 originates from the ocular choroid and may be a critical regulator for the cellular homeostasis of non-adipocyte HOCF cells. [ABSTRACT FROM AUTHOR]

Spontaneous miscarriage is a common complication of early pregnancy. Previous studies have shown that mitochondrial function plays an important role in establishment of a successful pregnancy. Cytochrome c oxidase subunit 4 isoform 1 (COX4I1), a component of electron transport chain complex Ⅳ, is required for coupling the rate of ATP production to energetic requirements. However, there is very limited research on its role in trophoblast biology and how its dysfunction may contribute to spontaneous miscarriage. Placental villi (7–10 weeks gestational age) collected from either induced termination of pregnancy or after spontaneous miscarriage were examined for expression of COX4I1. COX4I1 was knocked down by siRNA transfection of primary isolates of EVT cells. Real-time cell analysis (RTCA) and 5-Ethynyl-2′-deoxyuridine (EdU) were used to detect changes in proliferation ability after COX4I1 knockdown of EVT cells. Migration and invasion indices were determined by RTCA. Mitochondrial morphology was observed via MitoTracker staining. Oxidative phosphorylation, ATP production, and glycolysis in COX4I1-deficient cells and controls were assessed by a cellular energy metabolism analyzer (Seahorse). In placental villous tissue, COX4I1 expression was significantly decreased in the spontaneous miscarriage group. Knockdown of COX4I1 inhibited EVT cell proliferation, increased the migration and invasion ability and mitochondrial fusion of EVT cells. Mitochondrial respiration and glycolysis were impaired in COX4I1-deficient EVT cells. Knockdown of MMP1 could rescue the increased migration and invasion induced by COX4I1 silencing. Low expression of COX4I1 leads to mitochondrial dysfunction in EVT, resulting in altered trophoblast function, and ultimately to pregnancy loss. • COX4I1 expression is decreased in spontaneous miscarriage anchoring villi. • COX4I1 deficient EVT have reduced proliferation, increased migration/invasion. • COX4I1 deficient EVT contain dysfunctional mitochondria. [ABSTRACT FROM AUTHOR]

Aims: The conditions of hypoxia are suggested to induce permanent atrial fibrillation (AF). The regulation of COX4I2 and COX4I1 depends on oxygen availability in tissues. A role of COX4I2 in the myocardium of AF patients is supposed for pathogenesis of AF and subsequent alterations in the electron transfer chain (ETC) under hypoxia. Methods and results: In vitro, influence of hypoxia on HeLa 53 cells was studied and elevated parts of COX 4I2 were confirmed. Myocardial biopsies were taken ex vivo from the patients' Right Atria with SR (n = 31) and AF (n = 11), respectively. RT‐ PCR for mRNA expresson, mitochondrial respiration by polarography and the protein content of cytochrome c oxidase (CytOx) subunit 4I1 and CytOx subunit 4I2 by ELISA were studied. Clinical data were correlated to the findings of gene expressions in parallel. Patients with permanent AF had a change in isoform 4I2/4I1 expression along with a decrease of isoform COX 4I1 expression. The 4I2/4I1 ratio of mRNA expression was increased from 0.630 to 1.058 in comparison. However, the protein content of CytOx subunit 4 was much lower in the AF group, whereas the respiration/units enzyme activity in both groups remained the same. Conclusions: This study describes a possible molecular correlate for the development of AF. Due to the known functional significance of COX 4I2, mitochondrial dysfunction can be assumed as a part of the pathogenesis of AF. [ABSTRACT FROM AUTHOR]

Problem: Cardiorespiratory fitness (CRF) and mitochondrial function are important factors in health and disease. Even in immune cells, an effective metabolism is crucial for most major cellular functions, such as T-cell proliferation. Little is known about the relationship between CRF and mitochondrial metabolism of immune cells. Methods: In this narrative review, we collected the most recent literature in the field of exercise immunology and mitochondrial immune cell metabolism. We included studies, which used Oxygraph-or Seahorse techniques for measurement of mitochondrial function in various immune cell populations and subtypes associated with topics in the field of exercise in health and disease. Results: 20 studies were included in our analysis. Cell populations were PBMCs (peripheral blood mononuclear **cells), lymphocytes, T cells, NK cells, platelets, and neutrophils. While mitochondrial function was inconstantly affected through acute bouts of exercise, most of the studies, which included training interventions, reported a higher mitochondrial function in immune cells, which were in some studies correlated with the CRF. In various disease conditions, mitochondrial function of immune cells was impaired compared to healthy controls. Discussion: If a regular exercise training is followed by an improvement in immune cell mitochondrial respiration, regular exercise could become even more important in the context of optimizing immune function and immune regulation in prevention and therapy. [ABSTRACT FROM AUTHOR]

IntroductionFamilial hypercholesterolemia, the highly prevalent form of dyslipidemia, is a well-known risk factor for premature heart disease and stroke worldwide. Statins, which inhibit 3-hydroxy 3-methylglutaryl coenzyme A (HMG-CoA) reductase, are the first-choice treatment for dyslipidemias, and have been effective in reducing the risk of stroke and myocardial infarction. However, emerging evidence indicates that statins may increase the incidence of new-onset type 2 diabetes by reducing β-cell mass and function. Notably, past in vitro reports studying the effects of statins on β-cells were performed without including free fatty acids in the model. This factor should have been addressed since these agents are used to treat individuals with hyperlipidemia.MethodsHere, we used a mouse insulinoma MIN6 β-cell culture model to assess the efficacy, cytotoxicity, and insulin-suppressive effects of simvastatin and pravastatin in the presence of palmitic, linoleic, and oleic acids cocktail to mimic mixed lipids challenge in a biologically relevant setting.Results and discussionOur findings indicate that simvastatin was more effective in lowering intracellular cholesterol but was more cytotoxic as compared to pravastatin. Similarly, simvastatin exhibited a higher suppression of total insulin content and insulin secretion. Both drugs suppressed insulin secretion in phases 1 and 2, dose-dependently. No significant effect was observed on mitochondrial respiration. More importantly, elution experiments showed that insulin content diminution by simvastatin treatment was reversible, while exogenous mevalonate did not improve total insulin content. This suggests that simvastatin's influence on insulin content is independent of its specific inhibitory action on HMG-CoA reductase. In conclusion, our study identified that simvastatin was more effective in lowering intracellular cholesterol, albeit it was more toxic and suppressive of β-cells function. Notably, this suppression was found to be reversible.

Phoenixin (PNX) is an emerging neuropeptide that plays a significant role in regulating metabolism and reproduction. This comprehensive review examines findings from human, in vivo, and in vitro studies to elucidate the functions of PNX in metabolic processes. PNX has been identified as a key player in essential metabolic pathways, including energy homeostasis, glucose, lipid and electrolyte metabolism, and mitochondrial dynamics. It modulates food and fluid intake, influences glucose and lipid profiles, and affects mitochondrial biogenesis and function. PNX is abundantly expressed in the hypothalamus, where it plays a crucial role in regulating reproductive hormone secretion and maintaining energy balance. Furthermore, PNX is also expressed in peripheral tissues such as the heart, spleen, and pancreas, indicating its involvement in the regulation of metabolism across central and peripheral systems. PNX is a therapeutic peptide that operates through the G protein-coupled receptor 173 (GPR173) at the molecular level. It activates signaling pathways such as cAMP-protein kinase A (PKA) and Epac-ERK, which are crucial for metabolic regulation. Research suggests that PNX may be effective in managing metabolic disorders like obesity and type 2 diabetes, as well as reproductive health issues like infertility. Since metabolic processes are closely linked to reproduction, further understanding of PNX’s role in these areas is necessary to develop effective management/treatments. This review aims to highlight PNX’s involvement in metabolism and identify gaps in current knowledge regarding its impact on human health. Understanding the mechanisms of PNX’s action is crucial for the development of novel therapeutic strategies for the treatment of metabolic disorders and reproductive health issues, which are significant public health concerns globally.

Abstract Background Myocarditis refers to an autoimmune inflammatory response of the myocardium with characterization of self-reactive CD4+ T cell activation, which lacks effective treatment and has a poor prognosis. Acacetin is a natural flavonoid product that has been reported to have anti-inflammatory effects. However, acacetin has not been investigated in myocarditis. Methods Oral acacetin treatment was administered in an experimental autoimmune myocarditis model established with myosin heavy chain-alpha peptide. Echocardiography, pathological staining, and RT-qPCR were used to detect cardiac function, myocardial injury, and inflammation levels. Flow cytometry was utilized to detect the effect of acacetin on CD4+ T cell function. RNA-seq, molecular docking, and microscale thermophoresis (MST) were employed to investigate potential mechanisms. Seahorse analysis, mitoSOX, JC-1, and mitotracker were utilized to detect the effect of acacetin on mitochondrial function. Results Acacetin attenuated cardiac injury and fibrosis as well as heart dysfunction, and reduced cardiac inflammatory cytokines and ratio of effector CD4+ T and Th17 cells. Acacetin inhibited CD4+ T cell activation, proliferation, and Th17 cell differentiation. Mechanistically, the effects of acacetin were related to reducing mitochondrial complex II activity thereby inhibiting mitochondrial respiration and mitochondrial reactive oxygen species in CD4+ T cells. Conclusion Acacetin may be a valuable therapeutic drug in treating CD4+ T cell-mediated myocarditis. Graphical Abstract

Abstract Oral cancer stands as a prevalent maligancy worldwide; however, its therapeutic potential is limited by undesired effects and complications. As a medicinal edible fungus, Chaga mushroom (Inonotus obliquus) exhibits anticancer effects across diverse cancers. Yet, the precise mechanisms underlying its efficacy remain unclear. We explored the detailed mechanisms underlying the anticancer action of Chaga mushroom extract in oral cancer cells (HSC-4). Following treatment with Chaga mushroom extracts, we analyzed cell viability, proliferation capacity, glycolysis, mitochondrial respiration, and apoptosis. Our findings revealed that the extract reduced cell viability and proliferation of HSC-4 cells while arresting their cell cycle via suppression of STAT3 activity. Regarding energy metabolism, Chaga mushroom extract inhibited glycolysis and mitochondrial membrane potential in HSC-4 cells, thereby triggering autophagy-mediated apoptotic cell death through activation of the p38 MAPK and NF-κB signaling pathways. Our results indicate that Chaga mushroom extract impedes oral cancer cell progression, by inhibiting cell cycle and proliferation, suppressing cancer cell energy metabolism, and promoting autophagy-mediated apoptotic cell death. These findings suggest that this extract is a promising supplementary medicine for the treatment of patients with oral cancer.

Abstract Background It is generally accepted that endothelial cells (ECs), primarily rely on glycolysis for ATP production, despite having functional mitochondria. However, it is also known that ECs are heterogeneous, and their phenotypic features depend on the vascular bed. Emerging evidence suggests that liver sinusoidal ECs (LSECs), located in the metabolically rich environment of the liver, show high metabolic plasticity. However, the substrate preference for energy metabolism in LSECs remains unclear. Methods Investigations were conducted in primary murine LSECs in vitro using the Seahorse XF technique for functional bioenergetic assays, untargeted mass spectrometry-based proteomics to analyse the LSEC proteome involved in energy metabolism pathways, liquid chromatography-tandem mass spectrometry-based analysis of acyl-carnitine species and Raman spectroscopy imaging to track intracellular palmitic acid. Results This study comprehensively characterized the energy metabolism of LSECs, which were found to depend on oxidative phosphorylation, efficiently fuelled by glucose-derived pyruvate, short- and medium-chain fatty acids and glutamine. Furthermore, despite its high availability, palmitic acid was not directly oxidized in LSEC mitochondria, as evidenced by the acylcarnitine profile and etomoxir’s lack of effect on oxygen consumption. However, together with l-carnitine, palmitic acid supported mitochondrial respiration, which is compatible with the chain-shortening role of peroxisomal β-oxidation of long-chain fatty acids before further degradation and energy generation in mitochondria. Conclusions LSECs show a unique bioenergetic profile of highly metabolically plastic ECs adapted to the liver environment. The functional reliance of LSECs on oxidative phosphorylation, which is not a typical feature of ECs, remains to be determined.

ABSTRACT: Heat stress causes barrier dysfunction and inflammation of the small intestine of several species. However, less is known about the molecular and cellular mechanisms underlying the response of the bovine large intestine to hyperthermia. We aimed to identify changes in the colon of dairy cows in response to constant heat stress using a proteomic approach. Eighteen lactating Holstein dairy cows were kept under constant thermoneutral conditions (16°C and 68% relative humidity [RH]; temperature-humidity index [THI] = 60) for 6 d (period 1) with free access to feed and water. Thereafter, 6 cows were equally allocated to (1) thermoneutral condition with ad libitum feeding (TNAL; 16°C, RH = 68%, THI = 60), (2) heat stress condition (HS; 28°C, RH = 50%, THI = 76) with ad libitum feeding, or (3) pair-feeding at thermoneutrality (TNPF; 16°C, RH = 68%, THI = 60) for another 7 d (period 2). Rectal temperature, milk yield, dry matter and water intake were monitored daily. Then, cows were slaughtered and colon mucosa samples were taken for proteomic analysis. Physiological data were analyzed by ANOVA and colon proteome data were processed using DESeq2 package in R. Rectal temperature was significantly higher in HS than in TNPF and TNAL cows in period 2. Proteomic analysis revealed an enrichment of activated pathways related to colonic barrier function and inflammation, heat shock proteins, AA metabolism, reduced overall protein synthesis rate, and post-transcriptional regulation induced by heat stress. Further regulations were found for enzymes of the tricarboxylic acid cycle and components of the mitochondrial electron transport chain, presumably to reduce the generation of reactive oxygen species, maintain cellular ATP levels, and prevent apoptosis in the colon of HS cows. These results highlight the cellular, extracellular, and mitochondrial adaptations of the colon during heat stress and suggest a dysfunction of the hindgut barrier integrity potentially resulting in a “leaky” colon.

Abstract Background Muscle atrophy is a common consequence of the loss of innervation and is accompanied by mitochondrial dysfunction. Mitophagy is the adaptive process through which damaged mitochondria are removed via the lysosomes, which are regulated in part by the transcription factor TFE3. The role of lysosomes and TFE3 are poorly understood in muscle atrophy, and the effect of biological sex is widely underreported. Methods Wild-type (WT) mice, along with mice lacking TFE3 (KO), a transcriptional regulator of lysosomal and autophagy-related genes, were subjected to unilateral sciatic nerve denervation for up to 7 days, while the contralateral limb was sham-operated and served as an internal control. A subset of animals was treated with colchicine to capture mitophagy flux. Results WT females exhibited elevated oxygen consumption rates during active respiratory states compared to males, however this was blunted in the absence of TFE3. Females exhibited higher mitophagy flux rates and greater lysosomal content basally compared to males that was independent of TFE3 expression. Following denervation, female mice exhibited less muscle atrophy compared to male counterparts. Intriguingly, this sex-dependent muscle sparing was lost in the absence of TFE3. Denervation resulted in 45% and 27% losses of mitochondrial content in WT and KO males respectively, however females were completely protected against this decline. Decreases in mitochondrial function were more severe in WT females compared to males following denervation, as ROS emission was 2.4-fold higher. In response to denervation, LC3-II mitophagy flux was reduced by 44% in females, likely contributing to the maintenance of mitochondrial content and elevated ROS emission, however this response was dysregulated in the absence of TFE3. While both males and females exhibited increased lysosomal content following denervation, this response was augmented in females in a TFE3-dependent manner. Conclusions Females have higher lysosomal content and mitophagy flux basally compared to males, likely contributing to the improved mitochondrial phenotype. Denervation-induced mitochondrial adaptations were sexually dimorphic, as females preferentially preserve content at the expense of function, while males display a tendency to maintain mitochondrial function. Our data illustrate that TFE3 is vital for the sex-dependent differences in mitochondrial function, and in determining the denervation-induced atrophy phenotype.

Mitochondrial dysfunction and 12-lipoxygenase (ALOX12)-derived 12(S)-HETE production have been associated with vascular inflammation and the pathogenesis of atherosclerosis. However, the role of ALOX12 in regulating vascular energy metabolism in vascular inflammation has not been studied to date. Using mitochondrial and glycolysis functional profiling with the Seahorse extracellular flux analyzer, metabolipidomics, and proteomic analysis (LC-MS/MS), we characterized alterations in vascular energy metabolism in 2- and 6-month-old ApoE/LDLR−/− vs. control C57BL/6 mice. We identified that aorta of 6-month-old ApoE/LDLR−/− mice displayed compromised mitochondrial metabolism manifested by the reduced expression of mitochondrial enzymes, impaired mitochondrial respiration, and consequently diminished respiratory reserve capacity. An increased flux through the glycolysis/lactate shuttle, the hexosamine biosynthetic pathway (HBP), and the pentose phosphate pathway (PPP) was also recognized. Interestingly, ALOX12−12-HETE was the most upregulated axis in eicosanoid metabolism and histological examinations indicated that ApoE/LDLR−/− mice showed increased aortic expression of ALOX12, particularly in early atherosclerotic plaque areas. Remarkably, the joint blocking of ALOX12 and activation of AMPK, but not AMPK activation alone, resulted in the reprogramming of vascular metabolism, with improved mitochondrial respiration and suppressed auxiliary pathways (HBP, PPP, itaconate shunt). In conclusion, excessive activation of the ALOX12–12-HETE pathway in vascular inflammation in early atherosclerosis inhibits AMPK-dependent regulation of vascular metabolism. Consequently, ALOX12 may represent a novel target to boost impaired vascular mitochondrial function in pro-atherosclerotic vascular inflammation.

Mitochondrial intermembrane space (IMS) harbors a series of small, evolutionarily conserved redox-active cysteine-rich proteins. These proteins are essential for the functioning of cytochrome c oxidase, but their role in maintaining cellular redox processes is unknown. Here, we find out that in the absence of two such cysteine-rich Cx9C-Cx10C proteins, cytochrome c oxidase subunit 12 (Cox12) or cytochrome c oxidase assembly factor 6 (Coa6), Saccharomyces cerevisiae cells become sensitive under the oxidative and nitrosative stress. Interestingly, knockout of COX12 generates a significant amount of endogenous reactive oxygen species (ROS) and reactive nitrogen species (RNS) as evidenced by FACS analysis. Moreover, cellular redox status, redox-active enzymes glutathione reductase, catalase, S-nitroso glutathione reductase, and protein nitration were significantly affected in Cox12 null cells. Further, we found that an overexpression of COX12 partially protects mitochondrial respiratory subunit Sdh2 under oxidative and nitrosative stress. Taken together, we provide proof of evidence that cysteine-rich proteins in the IMS dynamically control the cellular redox milieu and actively prevent reactive nitrogen and oxygen species generation.

Stem respiration is a quantitatively important, but poorly understood component of ecosystem carbon cycling in terrestrial ecosystems. However, a dynamic stem gas exchange system for quantifying real-time stem carbon dioxide (CO2) efflux (Es) is not commercially available resulting in limited observations based on the static method where air is recirculated through a stem enclosure. The static method has limited temporal resolution, suffers from condensation issues, requires a leak-free enclosure, which is often difficult to verify in the field, and requires physically removing the chamber or flushing it with ambient air before starting each measurement.•With the goal of improving our quantitative understanding of biophysical, physiological, biochemical, and environmental factors that influence diurnal Es patterns, here we present a custom system for quantifying real-time stem Es in remote tropical forests.•The system is low cost, lightweight, and waterproof with low power requirements (1.2-2.4 W) for real-time monitoring of stem Es using a 3D printed dynamic stem chamber and a 12V car battery. The design offers control over the flow rate through the stem chamber, eliminates the need for a pump to introduce air into the chamber, and water condensation issues by removing water vapor prior to CO2 analysis.•Following a simple CO2 infrared gas analyzer (IRGA) calibration and match procedure with a 400-ppm standard, we quantified diurnal Es observations over a 24-hours period during the summer growing season from an ash tree (Fraxinus sp.) in Fort Collins, Colorado. The results are consistent with previous laboratory and field studies that show Es can be suppressed during the day relative to the night.