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SUMMARY: Lipid remodeling plays a critical role in plant response to abiotic stress and metabolic perturbations. Key steps in this process involve modifications of phosphatidylcholine (PC) acyl chains mediated by lysophosphatidylcholine: acyl‐CoA acyltransferases (LPCATs) and phosphatidylcholine: diacylglycerol cholinephosphotransferase (ROD1). To assess their importance in lipid homeostasis, we took advantage of the trigalactosyldiacylglycerol1 (tgd1) mutant that exhibits marked increases in fatty acid synthesis and fatty acid flux through PC due to a block in inter‐organelle lipid trafficking. Here, we showed that the increased fatty acid synthesis in tgd1 is due to posttranslational activation of the plastidic acetyl‐coenzyme A carboxylase. Genetic analysis showed that knockout of LPCAT1 and 2 resulted in a lethal phenotype in tgd1. In addition, plants homozygous for lpcat2 and heterozygous for lpcat1 in the tgd1 background showed reduced levels of PC and triacylglycerols (TAG) and alterations in their fatty acid profiles. We further showed that disruption of ROD1 in tgd1 resulted in changes in fatty acid composition of PC and TAG, decreased leaf TAG content and reduced seedling growth. Together, our results reveal a critical role of LPCATs and ROD1 in maintaining cellular lipid homeostasis under conditions, in which fatty acid production largely exceeds the cellular demand for membrane lipid synthesis. Significance Statement: Characterization of tgd1 mutants reveals a critical role of PC remodeling mediated by LPCATs and ROD1 in maintaining cellular lipid homeostasis. [ABSTRACT FROM AUTHOR]

Sirtuin 1 (SIRT1) is a key upstream regulator of lipid metabolism; however, the molecular mechanisms by which SIRT1 regulates milk fat synthesis in dairy goats remain unclear. This study aimed to investigate the regulatory roles of SIRT1 in modulating lipid metabolism in goat mammary epithelial cells (GMECs) and its impact on the adipose triglyceride lipase (ATGL) promoter activity using RNA interference (RNAi) and gene overexpression techniques. The results showed that SIRT1 is significantly upregulated during lactation compared to the dry period. Additionally, SIRT1 knockdown notably increased the expressions of genes related to fatty acid synthesis (SREBP1, SCD1, FASN, ELOVL6), triacylglycerol (TAG) production (DGAT2, AGPAT6), and lipid droplet formation (PLIN2). Consistent with the transcriptional changes, SIRT1 knockdown significantly increased the intracellular contents of TAG and cholesterol and the lipid droplet abundance in the GMECs, while SIRT1 overexpression had the opposite effects. Furthermore, the co-overexpression of SIRT1 and Forkhead box protein O1 (FOXO1) led to a more pronounced increase in ATGL promoter activity, and the ability of SIRT1 to enhance ATGL promoter activity was nearly abolished when the FOXO1 binding sites (FKH1 and FKH2) were mutated, indicating that SIRT1 enhances the transcriptional activity of ATGL via the FKH element in the ATGL promoter. Collectively, our data reveal that SIRT1 enhances the transcriptional activity of ATGL through the FOXO1 binding sites located in the ATGL promoter, thereby regulating lipid metabolism. These findings provide novel insights into the role of SIRT1 in fatty acid metabolism in dairy goats. [ABSTRACT FROM AUTHOR]

The multifaceted roles of MYB transcriptional regulators are pivotal in orchestrating the complex processes of secondary metabolism, stress tolerance mechanisms, and life cycle progression and development. This study extensively examined the JrMYB genes using whole genome and transcriptomic data, focusing on identifying putative MYB genes associated with fatty acid metabolism. 126 MYB genes were identified within the walnut genome, characterized by hydrophilic proteins spanning lengths ranging from 78 to 1890 base pairs. Analysis of cis-acting elements within the promoter regions of MYB genes revealed many elements linked to cell development, environmental stress, and phytohormones. Transcriptomic data was utilized to examine the role of JrMYB genes in the biosynthesis of fatty acids in walnuts. The results revealed diverse expression of these genes across various tissue sites, displaying varying levels and distinct expression patterns. Furthermore, by integrating the results of the phylogenetic tree with the correlation of expression levels, a total of 10 genes potentially involved in the regulation of fatty acid synthesis were screened. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis was conducted on these 10 genes and further identified 4 candidate genes, and a transcription regulatory network involved in fatty acids metabolism was constructed. This study presents a systematic analysis of JrMYB genes, laying the groundwork for an in-depth exploration of the JrMYB genes family's function in regulating fatty acid synthesis. [ABSTRACT FROM AUTHOR]

The mandibular glands (MGs) of honey bee workers are key exocrine glands responsible for the biosynthesis of multiple royal jelly acids, which have important functions within the colony. However, our knowledge about the nutrition requirement of MGs is quite limited. Here, we artificially manipulated the nutritional status of caged honey bee workers (pollen and sugar candy, sugar candy only, soybean meal and sugar candy, stearic acid supplemented sugar candy or citric acid supplemented sugar candy). Then we measured their impact on the 10-hydroxy-2-decanoic acid (10-HDA) and 10-hydroxydecanoic acid (10-HDAA) content in honey bee heads to evaluate the synthesis ability of workers' MGs, and analyzed the protein content of MGs as well as gene expression in the MGs to reveal the possible physiological changes. Our result showed that nutrition strongly impacted the MGs acid synthesis, the 10-HDA and 10-HDAA contents were significantly higher in workers fed with pollen than with sugar candy only, while an additional supply of protein and organic acid showed no significant contribution. In addition, the 10-HDA/10-HDAA ratio was also significantly affected by the nutrition status. On the contrary, different diets showed no influence on the protein content or gene expressions of MGs, except that organic acid supplements could increase the expression of key genes in fatty acid β-oxidation pathways. Taken together, our study revealed that honey bee nutritional status is closely related to the function of worker MGs. The nutritional deficiency has a significant negative impact on the synthesis ability of worker MGs, but showed no effect on the physiology of MGs. [ABSTRACT FROM AUTHOR]

Insig-1 and Insig-2 are endoplasmic reticulum (ER) proteins that inhibit lipid synthesis by blocking transport of sterol regulatory element-binding proteins (SREBP-1 and SREBP-2) from ER to Golgi. In the Golgi, SREBPs are processed proteolytically to release their transcription-activating domains, which enhance the synthesis of fatty acids, triglycerides, and cholesterol. Heretofore, the two Insigs have redundant functions, and there is no rationale for two isoforms. The current data identify a specific function for Insig-2. We show that eicosapentaenoic acid (EPA), a polyunsaturated fatty acid, inhibits fatty acid synthesis in human fibroblasts and rat hepatocytes by activating adenylate cyclase, which induces protein kinase A (PKA) to phosphorylate serine-106 in Insig-2. Phosphorylated Insig-2 inhibits the proteolytic processing of SREBP-1, thereby blocking fatty acid synthesis. Phosphorylated Insig-2 does not block the processing of SREBP-2, which activates cholesterol synthesis. Insig-1 lacks serine-106 and is not phosphorylated at this site. EPA inhibition of SREBP-1 processing was reduced by the replacement of serine-106 in Insig-2 with alanine or by treatment with KT5720, a PKA inhibitor. Inhibition did not occur in mutant human fibroblasts that possess Insig-1 but lack Insig-2. These data provide an Insig-2- specific mechanism for the long-known inhibition of fatty acid synthesis by polyunsaturated fatty acids. [ABSTRACT FROM AUTHOR]

Abstract Background When subject to stress conditions such as nutrient limitation microalgae accumulate triacylglycerol (TAG). Fatty acid, a substrate for TAG synthesis is derived from de novo synthesis or by membrane remodeling. The model industrial alga Chlorella sorokiniana accumulates TAG and other storage compounds under nitrogen (N)-limited growth. Molecular mechanisms underlying these processes are still to be elucidated. Result Previously we used transcriptomics to explore the regulation of TAG synthesis in C. sorokiniana. Surprisingly, our analysis showed that the expression of several key genes encoding enzymes involved in plastidic fatty acid synthesis are significantly repressed. Metabolic labeling with radiolabeled acetate showed that de novo fatty acid synthesis is indeed downregulated under N-limitation. Likewise, inhibition of the Target of Rapamycin kinase (TOR), a key regulator of metabolism and growth, decreased fatty acid synthesis. We compared the changes in proteins and phosphoprotein abundance using a proteomics and phosphoproteomics approach in C. sorokiniana cells under N-limitation or TOR inhibition and found extensive overlap between the N-limited and TOR-inhibited conditions. We also identified changes in the phosphorylation status of TOR complex proteins, TOR-kinase, and RAPTOR, under N-limitation. This indicates that TOR signaling is altered in a nitrogen-dependent manner. We find that TOR-mediated metabolic remodeling of fatty acid synthesis under N-limitation is conserved in the chlorophyte algae Chlorella sorokiniana and Chlamydomonas reinhardtii. Conclusion Our results indicate that under N-limitation there is significant metabolic remodeling, including fatty acid synthesis, mediated by TOR signaling. This process is conserved across chlorophyte algae. Using proteomic and phosphoproteomic analysis, we show that N-limitation affects TOR signaling and this in-turn affects the metabolic status of the cells. This study presents a link between N-limitation, TOR signaling and fatty acid synthesis in green-lineage.

The committed step for de novo fatty acid (FA) synthesis is the ATP-dependent carboxylation of acetyl-coenzyme A catalysed by acetyl-CoA carboxylase (ACCase). In most plants, ACCase is a multi-subunit complex orthologous to prokaryotes. However, unlike prokaryotes, the plant and algal orthologues are comprised both catalytic and additional dedicated regulatory subunits. Novel regulatory subunits, biotin lipoyl attachment domain-containing proteins (BADC) and carboxyltransferase interactors (CTI) (both three-gene families in Arabidopsis) represent new effectors specific to plants and certain algal species. The evolutionary history of these genes in autotrophic eukaryotes remains elusive, making it an ongoing area of research. Analyses of potential protein–protein and co-occurrence interactions, informed by gene network patterns using the STRING database, in Arabidopsis thaliana and Chlamydomonas reinhardtii unveil intricate gene associations with ACCase, suggesting a complex interplay between FA synthesis and other cellular processes. Among both species, a higher number of co-expressed genes was identified in Arabidopsis, indicating a wider potential regulatory network of ACCase in plants. This review investigates the extent to which these genes arose in autotrophic eukaryotes and provides insights into their evolutionary trajectory. This article is part of the theme issue 'The evolution of plant metabolism'. [ABSTRACT FROM AUTHOR]

Nucleoside diphosphate (NDP) kinases 1 and 2 (NME1/2) are well-characterized enzymes known for their NDP kinase activity. Recently, these enzymes have been shown by independent studies to bind coenzyme A (CoA) or acyl-CoA. These findings suggest a hitherto unknown role for NME1/2 in the regulation of CoA/acyl-CoA-dependent metabolic pathways, in tight correlation with the cellular NTP/NDP ratio. Accordingly, the regulation of NME1/2 functions by CoA/acyl-CoA binding has been described, and additionally, NME1/2 have been shown to control the cellular pathways consuming acetyl-CoA, such as histone acetylation and fatty acid synthesis. NME1/2-controlled histone acetylation in turn mediates an important transcriptional response to metabolic changes, such as those induced following a high-fat diet (HFD). This review discusses the CoA/acyl-CoA-dependent NME1/2 activities and proposes that these enzymes be considered as the first identified carriers of CoA/short-chain acyl-CoAs. [ABSTRACT FROM AUTHOR]

Summary Camelina (Camelina sativa L.), a hexaploid member of the Brassicaceae family, is an emerging oilseed crop being developed to meet the increasing demand for plant oils as biofuel feedstocks. In other Brassicas, high oil content can be associated with a yellow seed phenotype, which is unknown for camelina. We sought to create yellow seed camelina using CRISPR/Cas9 technology to disrupt its Transparent Testa 8 (TT8) transcription factor genes and to evaluate the resulting seed phenotype. We identified three TT8 genes, one in each of the three camelina subgenomes, and obtained independent CsTT8 lines containing frameshift edits. Disruption of TT8 caused seed coat colour to change from brown to yellow reflecting their reduced flavonoid accumulation of up to 44%, and the loss of a well‐organized seed coat mucilage layer. Transcriptomic analysis of CsTT8‐edited seeds revealed significantly increased expression of the lipid‐related transcription factors LEC1, LEC2, FUS3, and WRI1 and their downstream fatty acid synthesis‐related targets. These changes caused metabolic remodelling with increased fatty acid synthesis rates and corresponding increases in total fatty acid (TFA) accumulation from 32.4% to as high as 38.0% of seed weight, and TAG yield by more than 21% without significant changes in starch or protein levels compared to parental line. These data highlight the effectiveness of CRISPR in creating novel enhanced‐oil germplasm in camelina. The resulting lines may directly contribute to future net‐zero carbon energy production or be combined with other traits to produce desired lipid‐derived bioproducts at high yields. [ABSTRACT FROM AUTHOR]

Peroxisome proliferator-activated receptor γ (PPARG) has various splicing variants and plays essential roles in the regulation of adipocyte differentiation and lipogenesis. However, little is known about the expression pattern and effect of the PPARG on milk fat synthesis in the buffalo mammary gland. In this study, we found that only PPARG-X17 and PPARG-X21 of the splicing variant were expressed in the buffalo mammary gland. Amino acid sequence characterization showed that the proteins encoded by PPARG-X17 and PPARG-X21 are endonuclear non-secreted hydrophilic proteins. Protein domain prediction found that only the PPARG-X21-encoded protein had PPAR ligand-binding domains (NR_LBD_PPAR), which may lead to functional differences between the two splices. RNA interference (RNAi) and the overexpression of PPARG-X17 and PPARG-X21 in buffalo mammary epithelial cells (BMECs) were performed. Results showed that the expression of fatty acid synthesis-related genes (ACACA, CD36, ACSL1, GPAT, AGPAT6, DGAT1) was significantly modified (p < 0.05) by the RNAi and overexpression of PPARG-X17 and PPARG-X21. All kinds of FAs detected in this study were significantly decreased (p < 0.05) after RNAi of PPARG-X17 or PPARG-X21. Overexpression of PPARG-X17 or PPARG-X21 significantly decreased (p < 0.05) the SFA content, while significantly increased (p < 0.05) the UFA, especially the MUFA in the BMECs. In conclusion, there are two PPARG splicing variants expressed in the BMECs that can regulate FA synthesis by altering the expression of diverse fatty acid synthesis-related genes. This study revealed the expression characteristics and functions of the PPARG gene in buffalo mammary glands and provided a reference for further understanding of fat synthesis in buffalo milk. [ABSTRACT FROM AUTHOR]

Dimethyloxalylglycine (DMOG) is a representative inhibitor of the prolyl hydroxylase domain (PHD), which mediates the degradation of hypoxia-inducible factor-1-alpha (HIF1A). DMOG exerts its pharmacological effects via the canonical pathway that involves PHD inhibition; however, it remains unclear whether DMOG affects lipogenic gene expression in hepatocytes. We aimed to elucidate the effects of DMOG on sterol regulatory element-binding protein-1c (SREBP1c), a master regulator of fatty acid synthesis in hepatocytes. DMOG treatment inhibited SREBP1c mRNA and protein expression in HepG2 and AML12 hepatocytes and reduced the transcript levels of SREBP1c-regulated lipogenic genes. A luciferase reporter assay revealed that DMOG inhibited the transcriptional activity of SREBP1c. Moreover, DMOG suppressed SREBP1c expression in mice liver. Mechanistically, treatment with DMOG enhanced the expression of HIF1A and insulin-induced gene 2 (INSIG2), which inhibits the activation of SREBP1c. However, HIF1A or INSIG2 knockdown failed to reverse the inhibitory effect of DMOG on SREBP1c expression, suggesting a redundant role of HIF1A and INSIG2 in terms of repressing SREBP1c. DMOG did not function through the canonical pathway involving inhibition of SREBP1c by PHD, highlighting the presence of non-canonical pathways that mediate its anti-lipogenic effect.

Abstract Background Polycystic ovary syndrome (PCOS) is one of the most complex endocrine disorders in women of reproductive age. Abnormal proliferation of granulosa cells (GCs) is an important cause of PCOS. This study aimed to explore the role of fatty acid-binding protein 5 (FABP5) in granulosa cell (GC) proliferation in polycystic ovary syndrome (PCOS) patients. Methods The FABP5 gene, which is related to lipid metabolism, was identified through data analysis of the gene expression profiles of GSE138518 from the Gene Expression Omnibus (GEO) database. The expression levels of FABP5 were measured by quantitative real-time PCR (qRT‒PCR) and western blotting. Cell proliferation was evaluated with a cell counting kit-8 (CCK-8) assay. Western blotting was used to assess the expression of the proliferation marker PCNA, and immunofluorescence microscopy was used to detect Ki67 expression. Moreover, lipid droplet formation was detected with Nile red staining, and qRT‒PCR was used to analyze fatty acid storage-related gene expression. Results We found that FABP5 was upregulated in ovarian GCs obtained from PCOS patients and PCOS mice. FABP5 knockdown suppressed lipid droplet formation and proliferation in a human granulosa-like tumor cell line (KGN), whereas FABP5 overexpression significantly enhanced lipid droplet formation and KGN cell proliferation. Moreover, we determined that FABP5 knockdown inhibited PI3K-AKT signaling by suppressing AKT phosphorylation and that FABP5 overexpression activated PI3K-AKT signaling by facilitating AKT phosphorylation. Finally, we used the PI3K-AKT signaling pathway inhibitor LY294002 and found that the facilitation of KGN cell proliferation and lipid droplet formation induced by FABP5 overexpression was inhibited. In contrast, the PI3K-AKT signaling pathway agonist SC79 significantly rescued the suppression of KGN cell proliferation and lipid droplet formation caused by FABP5 knockdown. Conclusions FABP5 promotes active fatty acid synthesis and excessive proliferation of GCs by activating PI3K-AKT signaling, suggesting that abnormally high expression of FABP5 in GCs may be a novel biomarker or a research target for PCOS treatment.

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive disease caused by an aberrant repair of injured alveolar epithelial cells. The maintenance of the alveolar epithelium and its regeneration after the damage is fueled by alveolar type II (ATII) cells. Injured cells release exosomes containing microRNAs (miRNAs), which can alter the recipient cells' function. Lung tissue, ATII cells, fibroblasts, plasma, and exosomes were obtained from naive patients with IPF, patients with IPF taking pirfenidone or nintedanib, and control organ donors. miRNA expression was analyzed to study their impact on exosome-mediated effects in IPF. High miR-143-5p and miR-342-5p levels were detected in ATII cells, lung tissue, plasma, and exosomes in naive patients with IPF. Decreased FASN (fatty acid synthase) and ACSL-4 (acyl-CoA-synthetase long-chain family member 4) expression was found in ATII cells. miR-143-5p and miR-342-5p overexpression or ATII cell treatment with IPF-derived exosomes containing these miRNAs lowered FASN and ACSL-4 levels. Also, this contributed to ATII cell injury and senescence. However, exosomes isolated from patients with IPF taking nintedanib or pirfenidone increased FASN expression in ATII cells compared with naive patients with IPF. Furthermore, fibroblast treatment with exosomes obtained from naive patients with IPF increased SMAD3, CTGF, COL3A1, and TGFβ1 expression. Our results suggest that IPF-derived exosomes containing miR-143-5p and miR-342-5p inhibited the de novo fatty acid synthesis pathway in ATII cells. They also induced the profibrotic response in fibroblasts. Pirfenidone and nintedanib improved ATII cell function and inhibited fibrogenesis. This study highlights the importance of exosomes in IPF pathophysiology. [ABSTRACT FROM AUTHOR]

M1 (LPS) macrophages are characterized by a high expression of pro-inflammatory mediators, and distinct metabolic features that comprise increased glycolysis, a broken TCA cycle, or impaired OXPHOS with augmented mitochondrial ROS production. This study investigated whether the phytochemical sulforaphane (Sfn) influences mitochondrial reprogramming during M1 polarization, as well as to what extent this can contribute to Sfn-mediated inhibition of M1 marker expression in murine macrophages. The use of extracellular flux-, metabolite-, and immunoblot analyses as well as fluorescent dyes indicative for mitochondrial morphology, membrane potential or superoxide production, demonstrated that M1 (LPS/Sfn) macrophages maintain an unbroken TCA cycle, higher OXPHOS rate, boosted fusion dynamics, lower membrane potential, and less superoxide production in their mitochondria when compared to control M1 (LPS) cells. Sustained OXPHOS and TCA activity but not the concomitantly observed high dependency on fatty acids as fuel appeared necessary for M1 (LPS/Sfn) macrophages to reduce expression of nos2, il1β, il6 and tnfα. M1 (LPS/Sfn) macrophages also displayed lower nucleo/cytosolic acetyl-CoA levels in association with lower global and site-specific histone acetylation at selected pro-inflammatory gene promoters than M1 (LPS), evident in colorimetric coupled enzyme assays, immunoblot and ChIP-qPCR analyses, respectively. Supplementation with acetate or citrate was able to rescue both histone acetylation and mRNA expression of the investigated M1 marker genes in Sfn-treated cells. Overall, Sfn preserves mitochondrial functionality and restricts indispensable nuclear acetyl-CoA for histone acetylation and M1 marker expression in LPS-stimulated macrophages. [Display omitted] • Sfn prevents mitochondrial reprogramming from ATP to ROS production in M1 (LPS) macrophages. • OXPHOS activity supports the anti-inflammatory potential of Sfn. • Increased dependency on fatty acid oxidation alone is insufficient for reduced marker gene expression in M1 (LPS/Sfn) macrophages. • Limited extramitochondrial acetyl-CoA and reduced histone acetylation blunt M1 marker expression in M1 (LPS/Sfn) macrophages. [ABSTRACT FROM AUTHOR]

In this study, a detailed phytochemical investigation of compounds in the twigs of the mistletoe Loranthus europaeus Jacq., which belongs to the Loranthaceae family, is presented. Specimens were collected from the mistletoe L. europaeus growing on oak trees in the mainland of Greece. The alliance of oaks and mistletoes became a symbol of knowledge and strength for many centuries. Although numerous compounds of aerial tissues of other mistletoes, e.g., Viscum album, have been published, few studies have been conducted to investigate the metabolic and physiological traits of the hemiparasitic, deciduous Loranthus europaeus. LC-HRMS-based analysis led to a detailed characterization of ethyl acetate and dichloromethane extracts of the twigs of L. europaeus, which, to the best of our knowledge, exhibit enhanced antioxidant potential. Hence, twenty-four and twenty-six compounds were tentatively identified from the ethyl acetate and dichloromethane twigs' extracts, respectively; these compounds belong to fatty acids, flavonoids, and flavonoid glycosides. Also, chlorophyll, soluble sugar, starch, and lipid contents in the twigs of L. europaeus, which have not hitherto been published, were investigated. [ABSTRACT FROM AUTHOR]

Rationale: The plasma ceramide levels in Alzheimer's disease (AD) patients are found abnormally elevated, which is related to cognitive decline. Objectives: This research was aimed to investigate the mechanisms of aberrant elevated ceramides in the pathogenesis of AD. Results: The ICR mice intracerebroventricularly injected with Aβ1-42 and APP/PS1 transgenic mice were employed as AD mice. The cognitive deficiency, impaired episodic and spatial memory were observed without altered spontaneous ability. The serum levels of p-tau and ceramide were evidently elevated. The modified expressions and activities of glycogen synthase kinase-3β (GSK-3β) and protein phosphatase 2A (PP2A) influenced the serum content of p-tau. The levels of ceramide synthesis-related genes including sptlc1, sptlc2, cers2, and cers6 in the liver of AD mice were increased, while the ceramide degradation-related gene asah2 did not significantly change. The regulations of these genes were conducted by activated nuclear factor kappa-B (NF-κB) signaling. NF-κB, promoted by free fatty acid (FFA), also increased the hepatic concentrations of proinflammatory cytokines. The FFA amount was modulated by fatty acid synthesis-related genes acc1 and srebp-1c. Besides, the decreased levels of pre-proopiomelanocortin (pomc) mRNA and increased agouti-related protein (agrp) mRNA were found in the hypothalamus without significant alteration of melanocortin receptor 4 (MC4R) mRNA. The bioinformatic analyses proved the results using GEO datasets and AlzData. Conclusions: Ceramide was positively related to the increased p-tau and impaired cognitive function. The increased generation of ceramide and endoplasmic reticulum stress in the hypothalamus was positively related to fatty acid synthesis and NF-κB signaling via brain–liver axis. [ABSTRACT FROM AUTHOR]

Testosterone is closely associated with lipid metabolism and known to affect body fat composition and muscle mass in males. However, the mechanisms by which testosterone acts on lipid metabolism are not yet fully understood, especially in teleosts. In this study, cyp17a1-/- zebrafish (Danio rerio) exhibited excessive visceral adipose tissue (VAT), lipid content, and up-regulated expression and activity of hepatic de novo lipogenesis (DNL) enzymes. The assay for transposase accessible chromatin with sequencing (ATAC-seq) results demonstrated that chromatin accessibility of DNL genes was increased in cyp17a1-/- fish compared to cyp17a1+/+ male fish, including stearoyl-CoA desaturase (scd) and fatty acid synthase (fasn). Androgen response element (ARE) motifs in the androgen signaling pathway were significantly enriched in cyp17a1+/+ male fish but not in cyp17a1-/- fish. Both androgen receptor (ar)-/- and wildtype (WT) zebrafish administered with Ar antagonist flutamide displayed excessive visceral adipose tissue, lipid content, and up-regulated expression and activity of hepatic de novo lipogenesis enzymes. The Ar agonist BMS-564929 reduced the content of VAT and lipid content, and down-regulated acetyl-CoA carboxylase a (acaca), fasn, and scd expression. Mechanistically, the rescue effect of testosterone on cyp17a1-/- fish in terms of phenotypes was abolished when ar was additionally depleted. Collectively, these findings reveal that testosterone inhibits lipid deposition by down-regulating DNL genes via Ar in zebrafish, thus expanding our understanding of the relationship between testosterone and lipid metabolism in teleosts. [ABSTRACT FROM AUTHOR]

In this paper, we present a one‐pot protocol that enables a straightforward and selective transformation of alkyl benzothiazol‐2‐yl and phenyltetrazol‐2‐yl sulfones and acyl chlorides into ketones, E‐olefins, Z‐olefins, and even pyrroles. The final product of the reaction depends on the proper choice of the reaction workup. Notably, the protocol designed for olefin formation allows a switch between E‐ and Z‐olefin formation by the correct choice of the reaction workup. These developed protocols facilitate the formation of all compounds under mild reaction conditions, as evidenced by the synthesis of (nitro)‐fatty acids, and the concept can be extended to other product formations, as demonstrated by the synthesis of pyrroles. [ABSTRACT FROM AUTHOR]

Background: Polycystic ovary syndrome (PCOS) is one of the most complex endocrine disorders in women of reproductive age. Abnormal proliferation of granulosa cells (GCs) is an important cause of PCOS. This study aimed to explore the role of fatty acid-binding protein 5 (FABP5) in granulosa cell (GC) proliferation in polycystic ovary syndrome (PCOS) patients. Methods: The FABP5 gene, which is related to lipid metabolism, was identified through data analysis of the gene expression profiles of GSE138518 from the Gene Expression Omnibus (GEO) database. The expression levels of FABP5 were measured by quantitative real-time PCR (qRT‒PCR) and western blotting. Cell proliferation was evaluated with a cell counting kit-8 (CCK-8) assay. Western blotting was used to assess the expression of the proliferation marker PCNA, and immunofluorescence microscopy was used to detect Ki67 expression. Moreover, lipid droplet formation was detected with Nile red staining, and qRT‒PCR was used to analyze fatty acid storage-related gene expression. Results: We found that FABP5 was upregulated in ovarian GCs obtained from PCOS patients and PCOS mice. FABP5 knockdown suppressed lipid droplet formation and proliferation in a human granulosa-like tumor cell line (KGN), whereas FABP5 overexpression significantly enhanced lipid droplet formation and KGN cell proliferation. Moreover, we determined that FABP5 knockdown inhibited PI3K-AKT signaling by suppressing AKT phosphorylation and that FABP5 overexpression activated PI3K-AKT signaling by facilitating AKT phosphorylation. Finally, we used the PI3K-AKT signaling pathway inhibitor LY294002 and found that the facilitation of KGN cell proliferation and lipid droplet formation induced by FABP5 overexpression was inhibited. In contrast, the PI3K-AKT signaling pathway agonist SC79 significantly rescued the suppression of KGN cell proliferation and lipid droplet formation caused by FABP5 knockdown. Conclusions: FABP5 promotes active fatty acid synthesis and excessive proliferation of GCs by activating PI3K-AKT signaling, suggesting that abnormally high expression of FABP5 in GCs may be a novel biomarker or a research target for PCOS treatment. [ABSTRACT FROM AUTHOR]

De novo lipogenesis (DNL) converts carbon substrates to lipids. Increased hepatic DNL could contribute to pathogenic liver triglyceride accumulation in nonalcoholic steatohepatitis (NASH) and therefore may be a potential target for pharmacological intervention. Here, we measured hepatic DNL using heavy water in 123 patients with NASH with fibrosis or cirrhosis, calculated the turnover of hepatic triglycerides to allow repeat labeling studies, and determined the associations of hepatic DNL with metabolic, fibrotic, and imaging markers. We found that hepatic DNL was higher in patients with fibrotic NASH [median (IQR), 40.7% contribution to palmitate (32.1, 47.5), n=103] than has been previously reported in healthy volunteers and remained elevated [median (IQR), 36.8% (31.0, 44.5), n=20] in patients with cirrhosis, despite lower liver fat content. We also showed that turnover of intrahepatic triglyceride pools was slow (t½ >10 days). Furthermore, DNL contribution was determined to be independent of liver stiffness by magnetic resonance imaging but was positively associated with the number of large very low density lipoprotein (VLDL) particles, the size of VLDL, the lipoprotein insulin resistance score, and levels of ApoB100, and trended toward negative associations with the fibrosis markers FIB-4, FibroSure, and APRI. Finally, we found treatment with the acetyl-CoA carboxylase inhibitor firsocostat reduced hepatic DNL at 4 and 12 weeks, using a correction model for residual label that accounts for hepatic triglyceride turnover. Taken together, these data support an important pathophysiological role for elevated hepatic DNL in NASH and demonstrate that response to pharmacological agents targeting DNL can be correlated with pretreatment DNL.

Sirtuin 1 (SIRT1) is a key upstream regulator of lipid metabolism; however, the molecular mechanisms by which SIRT1 regulates milk fat synthesis in dairy goats remain unclear. This study aimed to investigate the regulatory roles of SIRT1 in modulating lipid metabolism in goat mammary epithelial cells (GMECs) and its impact on the adipose triglyceride lipase (ATGL) promoter activity using RNA interference (RNAi) and gene overexpression techniques. The results showed that SIRT1 is significantly upregulated during lactation compared to the dry period. Additionally, SIRT1 knockdown notably increased the expressions of genes related to fatty acid synthesis (SREBP1, SCD1, FASN, ELOVL6), triacylglycerol (TAG) production (DGAT2, AGPAT6), and lipid droplet formation (PLIN2). Consistent with the transcriptional changes, SIRT1 knockdown significantly increased the intracellular contents of TAG and cholesterol and the lipid droplet abundance in the GMECs, while SIRT1 overexpression had the opposite effects. Furthermore, the co-overexpression of SIRT1 and Forkhead box protein O1 (FOXO1) led to a more pronounced increase in ATGL promoter activity, and the ability of SIRT1 to enhance ATGL promoter activity was nearly abolished when the FOXO1 binding sites (FKH1 and FKH2) were mutated, indicating that SIRT1 enhances the transcriptional activity of ATGL via the FKH element in the ATGL promoter. Collectively, our data reveal that SIRT1 enhances the transcriptional activity of ATGL through the FOXO1 binding sites located in the ATGL promoter, thereby regulating lipid metabolism. These findings provide novel insights into the role of SIRT1 in fatty acid metabolism in dairy goats.

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is rapidly increasing worldwide at an alarming pace, due to an increase in obesity, sedentary and unhealthy lifestyles, and unbalanced dietary habits. MASLD is a unique, multi-factorial condition with several phases of progression including steatosis, steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. Sterol element binding protein 1c (SREBP1c) is the main transcription factor involved in regulating hepatic de novo lipogenesis. This transcription factor is synthesized as an inactive precursor, and its proteolytic maturation is initiated in the membrane of the endoplasmic reticulum upon stimulation by insulin. SREBP cleavage activating protein (SCAP) is required as a chaperon protein to escort SREBP from the endoplasmic reticulum and to facilitate the proteolytic release of the N-terminal domain of SREBP into the Golgi. SCAP inhibition prevents activation of SREBP and inhibits the expression of genes involved in triglyceride and fatty acid synthesis, resulting in the inhibition of de novo lipogenesis. In line, previous studies have shown that SCAP inhibition can resolve hepatic steatosis in animal models and intensive research is going on to understand the effects of SCAP in the pathogenesis of human disease. This review focuses on the versatile roles of SCAP/SREBP regulation in de novo lipogenesis and the structure and molecular features of SCAP/SREBP in the progression of hepatic steatosis. In addition, recent studies that attempt to target the SCAP/SREBP axis as a therapeutic option to interfere with MASLD are discussed. [ABSTRACT FROM AUTHOR]

Background and aims: Wnt/β-catenin signaling plays an important role in regulating hepatic metabolism. This study is to explore the molecular mechanisms underlying the potential crosstalk between Wnt/b-catenin and mTOR signaling in hepatic steatosis. Methods: Transgenic mice (overexpress Wnt1 in hepatocytes, Wnt+) mice and wild-type littermates were given high fat diet (HFD) for 12 weeks to induce hepatic steatosis. Mouse hepatocytes cells (AML12) and those transfected to cause constitutive b-catenin stabilization (S33Y) were treated with oleic acid for lipid accumulation. Results: Wnt+ mice developed more hepatic steatosis in response to HFD. Immunoblot shows a significant increase in the expression of fatty acid synthesisrelated genes (SREBP-1 and its downstream targets ACC, AceCS1, and FASN) and a decrease in fatty acid oxidation gene (MCAD) in Wnt+ mice livers under HFD. Wnt+ mice also revealed increased Akt signaling and its downstreamtarget genemTOR in response to HFD. In vitro, increased lipid accumulation was detected in S33Y cells in response to oleic acid compared to AML12 cells reinforcing the in vivo findings. mTOR inhibition by rapamycin led to a down-regulation of fatty acid synthesis in S33Y cells. In addition, β-catenin has a physical interaction with mTOR as verified by co-immunoprecipitation in hepatocytes. Conclusions: Taken together, our results demonstrate that β-catenin stabilization through Wnt signaling serves a central role in lipid metabolism in the steatotic liver through up-regulation of fatty acid synthesis via Akt/mTOR signaling. These findings suggest hepatic Wnt signaling may represent a therapeutic strategy in hepatic steatosis. [ABSTRACT FROM AUTHOR]

Cannabinoids are important therapeutical molecules for human ailments, cancer treatment, and SARS-CoV-2. The central cannabinoid, cannabigerolic acid (CBGA), is generated from geranyl pyrophosphate and olivetolic acid by Cannabis sativa prenyltransferase (CsPT4). Despite efforts to engineer microorganisms such as Saccharomyces cerevisiae (S. cerevisiae) for CBGA production, their titers remain suboptimal because of the low conversion of hexanoate into olivetolic acid and the limited activity and stability of the CsPT4. To address the low hexanoate conversion, we eliminated hexanoate consumption by the beta-oxidation pathway and reduced its incorporation into fatty acids. To address CsPT4 limitations, we expanded the endoplasmic reticulum and fused an auxiliary protein to CsPT4. Consequently, the engineered S. cerevisiae chassis showed a marked improvement of 78.64-fold in CBGA production, reaching a titer of 510.32 ± 10.70 mg l−1 from glucose and hexanoate. • Commercial production of cannabigerolic acid (CBGA) in S. cerevisiae presents challenges. • Blocking hexanoate degradation and optimizing pathway enzyme expression resulted in improved CBGA titers. • Fatty acid synthase confirmed cryptical utilization of hexanoyl-CoA. • Compartmentalization expansion and auxiliary partner fusion elevated activity and stability of prenyltransferase CsPT4. • Engineered CBGA-producing yeast yielded in 510 mg l−1 CBGA from cost-effective carbon source glucose and hexanoate. [ABSTRACT FROM AUTHOR]

ABSTRACT: As a metabolic disease, fatty liver hemorrhagic syndrome (FLHS) has emerged as a major cause of noninfectious mortality in laying hens, resulting in substantial economic losses to the poultry industry. This study aimed to investigate the therapeutic effects of magnolol on FLHS in postpeak laying hen model, focusing on lipid metabolism, antioxidative capacity, and potential molecular mechanisms of action. We selected 150 Xinhua laying hens aged 50 wk and divided them into normal diet group (ND), high-fat diet group (HFD), 100 mg/kg magnolol group (MG100), 300 mg/kg magnolol group (MG300), 500 mg/kg magnolol group (MG500) on average. The experiment lasted for 6 wk, and liver samples were collected from the hens at the end of the experiment. The results demonstrated that the inclusion of magnolol in the diet had a significant impact on various factors. It led to a reduction in weight, an increase in egg production rate, a decrease in blood lipid levels, and an improvement in abnormal liver function, liver steatosis, and oxidative stress. These effects were particularly prominent in the MG500 group. The RNA—Seq analysis demonstrated that in the MG500 group, there was a down-regulation of genes associated with fatty acid synthesis (Acc, Fasn, Scd, Srebf1, Elovl6) compared to the HFD group. Moreover, genes related to fatty acid oxidation (CPT1A and PGC1α) were found to be up-regulated. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of these differentially expressed genes indicated their enrichment in the PPAR signaling pathway. These findings demonstrate that magnolol can mitigate FLHS by inhibiting fatty acid synthesis and promoting fatty acid oxidation. This discovery offers a novel approach for treating FLHS in laying hens, reducing the economic losses associate with FLHS.

Abstract Background Dysregulation of lipid metabolism is the most prominent metabolic alteration observed in obesity, cancer, and cardiovascular diseases. The present study aimed to explore the sex differences associated with lipid metabolism in urinary exosome proteins, and evaluate the correlation of urinary exosome proteins with serum lipid biomarkers. Methods The key enzymes regulating lipid metabolism in healthy adults were screened using urinary exosome data. Urinary exosomes were isolated from 120 healthy subjects and the expression of urinary proteins was assessed by Western blotting and ELISA. The correlation between urinary protein concentrations and the levels of serum lipid biomarkers was analyzed using correlation analysis. Results Three urinary exosome proteins, namely fatty acid synthase (FASN), phosphoenolpyruvate carboxykinase (PCK1), and ATP-citrate synthase (ACLY) were identified, and only FASN showed sex differences. Sex differences were also observed in the serum triglyceride (TG) levels. Healthy males had higher FASN levels than females, and a moderate positive correlation was found between FASN concentrations and serum TG levels in healthy males (r = 0.479, P

Nucleoside diphosphate (NDP) kinases 1 and 2 (NME1/2) are well-characterized enzymes known for their NDP kinase activity. Recently, these enzymes have been shown by independent studies to bind coenzyme A (CoA) or acyl-CoA. These findings suggest a hitherto unknown role for NME1/2 in the regulation of CoA/acyl-CoA-dependent metabolic pathways, in tight correlation with the cellular NTP/NDP ratio. Accordingly, the regulation of NME1/2 functions by CoA/acyl-CoA binding has been described, and additionally, NME1/2 have been shown to control the cellular pathways consuming acetyl-CoA, such as histone acetylation and fatty acid synthesis. NME1/2-controlled histone acetylation in turn mediates an important transcriptional response to metabolic changes, such as those induced following a high-fat diet (HFD). This review discusses the CoA/acyl-CoA-dependent NME1/2 activities and proposes that these enzymes be considered as the first identified carriers of CoA/short-chain acyl-CoAs.

The increasing global prevalence of nonalcoholic fatty liver disease (NAFLD) starves for effective therapy, but no agent has been approved yet. We sought to evaluate the therapy of cefminox sodium (CMNX) on fatty accumulation in animal and cell models and explore the underlying mechanisms. The results revealed that CMNX reduced the gain of the liver and alleviated fatty accumulation both in high-fat high-sugar diet (HFHSD) mice's livers and WRL-68 cells. In HFHSD mice's livers and FFAs exposure hepatic cells, ACC1, SREBP-1c, and CYP2E1 were enhanced expression, which were reversed by CMNX treatment. In addition, PPARγ, PPARα, PCK1, and ACSL4 expressions were increased in CMNX-treated WRL-68 cells. These findings suggest that CMNX improves fatty accumulation in HFHSD mice/hepatic cells by restraining fatty acid synthesis and facilitating fatty acid oxidation.

Background: Dysregulation of lipid metabolism is the most prominent metabolic alteration observed in obesity, cancer, and cardiovascular diseases. The present study aimed to explore the sex differences associated with lipid metabolism in urinary exosome proteins, and evaluate the correlation of urinary exosome proteins with serum lipid biomarkers. Methods: The key enzymes regulating lipid metabolism in healthy adults were screened using urinary exosome data. Urinary exosomes were isolated from 120 healthy subjects and the expression of urinary proteins was assessed by Western blotting and ELISA. The correlation between urinary protein concentrations and the levels of serum lipid biomarkers was analyzed using correlation analysis. Results: Three urinary exosome proteins, namely fatty acid synthase (FASN), phosphoenolpyruvate carboxykinase (PCK1), and ATP-citrate synthase (ACLY) were identified, and only FASN showed sex differences. Sex differences were also observed in the serum triglyceride (TG) levels. Healthy males had higher FASN levels than females, and a moderate positive correlation was found between FASN concentrations and serum TG levels in healthy males (r = 0.479, P < 0.05). FASN concentrations in different age groups were positively correlated with the level of serum TG (18 ~ 30 years, r = 0.502; 31 ~ 44 years, r = 0.587; 45 ~ 59 years, r = 0.654; all P < 0.05). In addition, FASN concentrations was positively related to the increase in serum TG levels (range:1.0 ~ 1.7 mmol/L; r = 0.574, P < 0.05). Conclusions: Sex differences were observed in urinary exosome FASN protein levels in healthy adults. FASN protein levels positively correlated with increased serum TG levels. FASN may serve as a novel biomarker to evaluate fatty acid synthesis in the human body. [ABSTRACT FROM AUTHOR]

The synthesis of tea fatty acids plays a crucial role in determining the oil content of tea seeds and selecting tea tree varieties suitable for harvesting both leaves and fruits. However, there is limited research on fatty acid synthesis in tea trees, and the precise mechanisms influencing tea seed oil content remain elusive. To reveal the fatty acid biosynthesis mechanism, we conducted a photosynthetic characteristic and targeted metabolomics analysis in comparison between Jincha 2 and Wuniuzao cultivars. Our findings revealed that Jincha 2 exhibited significantly higher net photosynthetic rates (Pn), stomatal conductance (Gs), and transpiration rate (Tr) compared with Wuniuzao, indicating the superior photosynthetic capabilities of Jincha 2. Totally, we identified 94 metabolites with significant changes, including key hormone regulators such as gibberellin A1 (GA1) and indole 3-acetic acid (IAA). Additionally, linolenic acid, methyl dihydrojasmonate, and methylthiobutyric acid, precursors required for fatty acid synthesis, were significantly more abundant in Jincha 2 compared with Wuniuzao. In summary, our research suggests that photosynthetic rates and metabolites contribute to the increased yield, fatty acid synthesis, and oil content observed in Jincha 2 when compared with Wuniuzao. [ABSTRACT FROM AUTHOR]

Psoriasis is a chronic inflammatory skin disease driven by the IL-23/IL-17 axis. It results from excessive activation of effector T cells, including T helper (Th) and cytotoxic T (Tc) cells, and is associated with dysfunctional regulatory T cells (Tregs). Acetyl-CoA carboxylase 1 (ACC1), a rate-limiting enzyme of fatty acid synthesis (FAS), directs cell fate decisions between Th17 and Tregs and thus could be a promising therapeutic target for psoriasis treatment. Here, we demonstrate that targeting ACC1 in T cells by genetic ablation ameliorates skin inflammation in an experimental model of psoriasis by limiting Th17, Tc17, Th1, and Tc1 cells in skin lesions and increasing the frequency of effector Tregs in skin-draining lymph nodes (LNs). Key messages: ACC1 deficiency in T cells ameliorates psoriatic skin inflammation in mice. ACC1 deficiency in T cells reduces IL-17A-producing Th17/Tc17/dysfunctional Treg populations in psoriatic lesions. ACC1 deficiency in T cells restrains IFN-γ-producing Th1/Tc1 populations in psoriatic skin lesions and skin-draining LNs. ACC1 deficiency promotes activated CD44+CD25+ Tregs and effector CD62L-CD44+ Tregs under homeostasis and psoriatic conditions. [ABSTRACT FROM AUTHOR]

Simple Summary: Coated calcium pantothenate or coated thiamine supplementation potentially promotes milk production by stimulating nutrient digestion and fatty acids synthesis of the mammary gland in dairy cows. Owing to the synergistic effect of pantothenate and thiamine on the regulation of energy metabolism, the combined addition of coated calcium pantothenate and coated thiamine will more effectively promote lactation performance than that achieved by coated calcium pantothenate or coated thiamine alone. Further research is needed to determine the influences of coated calcium pantothenate or/and coated thiamine on the development of the mammary gland. Considering the synergistic effect of pantothenate and thiamine on the regulation of energy metabolism, this study investigated the influences of coated calcium pantothenate (CCP) and coated thiamine (CT) on milk production and composition, nutrients digestion, and expressions of genes involved in fatty acids synthesis in mammary glands. Forty-four multiparous Chinese Holstein cows (2.8 ± 0.19 of parity, 772 ± 12.3 kg of body weight [BW], 65.8 ± 8.6 days in milk [DIM] and 35.3 ± 1.9 kg/d of milk production, mean ± SD) were blocked by parity, BW, DIM, and milk production, and they were allocated into one of four treatments in a 2 × 2 factorial block design. Additional CCP (0 mg/kg [CCP−] or 55 mg/kg dry matter [DM] of calcium pantothenate from CCP [CCP+]) and CT (0 g/kg [CT−] or 5.3 mg/kg DM of thiamine from CT [CT+]) were hand-mixed into the top one-third of total mixed ration. Both CCP and CT additives increased milk production, fat content, true protein, and lactose by promoting nutrient digestibility. The CCP or/and CT supplementation induced the elevation of C11:0, C12:0, C13:0, C14:0, C14:1, C15:0, C15:1, C16:00, C16:1, C24:00, C24:1 fatty acids, saturated fatty acid, and C4-16 fatty acid contents in milk fat; but it decreased C17-22 fatty acid content. Ruminal total VFA content was increased, but pH was decreased by both additives. The ruminal fermentation pattern was altered, and a tendency of acetate formation was implied by the increased acetate-to-propionate ratio after both additives' supplementation. The expressions of PPARγ, SREBPF1, ACACA, FASN, SCD, and FABP3 mRNAs were enhanced by CCP or CT addition, but the relative expression of LPL mRNA was upregulated by CT addition only. Additionally, blood glucose, triglyceride, insulin-like growth factor-1, and total antioxidant capacity were promoted by both additives. The combination of CCP and CT more effectively increased the ruminal total VFA concentration, the acetate to propionate ratio, and blood glucose level, and decreased ammoniacal nitrogen concentration than that achieved by CCP or CT alone. The results suggested that CCP and CT supplementation stimulated lactation performance by promoting nutrient digestion and fatty acid synthesis in the mammary glands. [ABSTRACT FROM AUTHOR]

T helper (Th) 17 cells highly contribute to the immunopathology of rheumatoid arthritis. Morin, a natural flavonoid, owns well anti-arthritic action but unclear effect on Th17 differentiation. This study tried to solve this issue and explore the mechanisms in view of cellular metabolism. Naïve CD4+ T cells were treated with anti-CD3/CD28 along with Th17-inducing cytokines. Morin was shown to block Th17 differentiation without affecting cell viability even when Foxp3 was dampened. The mechanisms were ascribed to the limited fatty acid synthesis by restricting FASN transcription, as indicated by metabolomics analysis, nile red staining, detection of triglycerides, FASN overexpression, and addition of palmitic acid. Moreover, morin had slight effect on cell apoptosis and protein palmitoylation during Th17 differentiation, but blocked the binding of RORγt to promoter and CNS2 region of Il17a gene. Oleic acid rescued the inhibition of morin on RORγt function, and Th17-inducing cytokines could not induce RORγt function in SCD1-defficient cells, suggesting that oleic acid but not palmitic acid was the direct effector in the action of morin. Then, PPARγ was identified as the target of morin, and GW9662 or PPARγ CRISPR/Cas9 KO plasmid weakened its above-mentioned effects. The transrepression of FASN by morin was owing to physical interaction between PPARγ and Sp1, and the importance of Sp1 in Th17 differentiation was confirmed by siSp1. Finally, the effects and mechanisms for morin-dampened Th17 responses were confirmed in collagen-induced arthritis (CIA) mice. Collectively, morin inhibited Th17 differentiation and alleviated CIA by limiting fatty acid synthesis subsequent to PPARγ activation. [ABSTRACT FROM AUTHOR]

Pathways that govern cellular bioenergetics are deregulated in tumor cells and represent a hallmark of cancer. Tumor cells have the capacity to reprogram pathways that control nutrient acquisition, anabolism and catabolism to enhance their growth and survival. Tumorigenesis requires the autonomous reprogramming of key metabolic pathways that obtain, generate and produce metabolites from a nutrient-deprived tumor microenvironment to meet the increased bioenergetic demands of cancer cells. Intra- and extracellular factors also have a profound effect on gene expression to drive metabolic pathway reprogramming in not only cancer cells but also surrounding cell types that contribute to anti-tumor immunity. Despite a vast amount of genetic and histologic heterogeneity within and between cancer types, a finite set of pathways are commonly deregulated to support anabolism, catabolism and redox balance. Multiple myeloma (MM) is the second most common hematologic malignancy in adults and remains incurable in the vast majority of patients. Genetic events and the hypoxic bone marrow milieu deregulate glycolysis, glutaminolysis and fatty acid synthesis in MM cells to promote their proliferation, survival, metastasis, drug resistance and evasion of immunosurveillance. Here, we discuss mechanisms that disrupt metabolic pathways in MM cells to support the development of therapeutic resistance and thwart the effects of anti-myeloma immunity. A better understanding of the events that reprogram metabolism in myeloma and immune cells may reveal unforeseen vulnerabilities and advance the rational design of drug cocktails that improve patient survival. [ABSTRACT FROM AUTHOR]

We used transcriptome sequencing to investigate the hepatic postprandial responses of Rachycentron canadum (cobia), an important commercial fish species. In total, 150 cobia juveniles (50 per tank, triplicate) were fed ad libitum with a commercial diet for 7 days, fasted for 24 h, and fed for 10 min. The liver was sampled 10 min prior to feeding and 30 min, 1, 2, 4, 8, 12, and 24 h after the feeding event. Each sample was evaluated in terms of liver fatty acid profile and gene expression. Differential gene expressions were evaluated, focusing on fatty acid synthesis and oxidation pathways. In general, the liver fatty acid profile reflected diet composition. Docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) levels increased at 8 to 12 h but decreased at 24 h after the feeding event. A high number of differentially expressed genes (DEGs) were observed comparing fish that fasted for 8 h with those fasted for 30 min and 24 h, while a reduced number of DEGs was observed comparing individuals who fasted for 30 min compared with those who fasted for 24 h. Similarly, the main differences in the expression of genes related to the fatty acid biosynthesis and oxidation pathways were noticed in individuals who fasted for 8 h compared with those who fasted for 30 min and 24 h. The results suggested that the adequate time to sample the individuals ranged between 8 and 12 h after the meal since, apparently, after 24 h, differential gene expression was not necessarily influenced by food intake. [ABSTRACT FROM AUTHOR]

Cells build fatty acids in tightly regulated assembly lines, or fatty acid synthases (FASs), in which β-ketoacyl-acyl carrier protein (ACP) synthases (KSs) catalyze sequential carbon-carbon bond forming reactions that generate acyl-ACPs of varying lengths—precursors for a diverse set of lipids and oleochemicals. To date, most efforts to control fatty acid synthesis in engineered microbes have focused on modifying termination enzymes such as acyl-ACP thioesterases, which release free fatty acids from acyl-ACPs. Changes to the substrate specificity of KSs provide an alternative—and, perhaps, more generalizable—approach that focuses on controlling the acyl-ACPs available for downstream products. This study combines mutants of FabF and FabB, the two elongating KSs of the E. coli FAS, with in vitro and in vivo analyses to explore the use of KS mutants to control fatty acid synthesis. In vitro , single amino acid substitutions in the gating loop and acyl binding pocket of FabF shifted the product profiles of reconstituted FASs toward short chains and showed that KS mutants, alone, can cause large shifts in average length (i.e., 6.5–13.5). FabB, which is essential for unsaturated fatty acid synthesis, blunted this effect in vivo , but exogenously added cis-vaccenic acid (C18:1) enabled sufficient transcriptional repression of FabB to restore it. Strikingly, a single mutant of FabB afforded titers of octanoic acid as high as those generated by an engineered thioesterase. Findings indicate that fatty acid synthesis must be decoupled from microbial growth to resolve the influence of KS mutants on fatty acid profiles but show that these mutants offer a versatile approach for tuning FAS outputs. • Single amino acid mutations in the gating loop or acyl binding pocket of FabF and FabB cause major shifts in fatty acid profiles. • Fatty acid synthesis must be decoupled from cell growth to resolve the influence of KS mutants on fatty acid production. • FabB mutant G107M enables titers of octanoic acid that match those generated by an engineered C8-specific thioesterase. [ABSTRACT FROM AUTHOR]

The bacterial fatty acid pathway is essential for membrane synthesis and a range of other metabolic and cellular functions. The β-ketoacyl-ACP synthases carry out the initial elongation reaction of this pathway, utilizing acetyl-CoA as a primer to elongate malonyl-ACP by two carbons, and subsequent elongation of the fatty acyl-ACP substrate by two carbons. Here we describe the structures of the β-ketoacyl-ACP synthase I from Brucella melitensis in complex with platencin, 7-hydroxycoumarin, and (5-thiophen-2-ylisoxazol-3-yl)methanol. The enzyme is a dimer and based on structural and sequence conservation, harbors the same active site configuration as other β-ketoacyl-ACP synthases. The platencin binding site overlaps with the fatty acyl compound supplied by ACP, while 7-hydroxyl-coumarin and (5-thiophen-2-ylisoxazol-3-yl)methanol bind at the secondary fatty acyl binding site. These high-resolution structures, ranging between 1.25 and 1.70 å resolution, provide a basis for in silico inhibitor screening and optimization, and can aid in rational drug design by revealing the high-resolution binding interfaces of molecules at the malonyl-ACP and acyl-ACP active sites.

Abstract Background Abnormal expression of protein tyrosine phosphatases (PTPs) has been reported to be a crucial cause of cancer. As a member of PTPs, protein tyrosine phosphatase receptor type O (PTPRO) has been revealed to play tumor suppressive roles in several cancers, while its roles in colorectal cancer (CRC) remains to be elucidated. Hence, we aimed to explore the roles and mechanisms of PTPRO in CRC initiation and progression. Methods The influences of PTPRO on the growth and liver metastasis of CRC cells and the expression patterns of different lipid metabolism enzymes were evaluated in vitro and in vivo. Molecular and biological experiments were conducted to uncover the underpinning mechanisms of dysregulated de novo lipogenesis and fatty acid β‐oxidation. Results PTPRO expression was notably downregulated in CRC liver metastasis compared to the primary cancer, and such a downregulation was associated with poor prognosis of patients with CRC. PTPRO silencing significantly promoted cell growth and liver metastasis. Compared with PTPRO wild‐type mice, PTPRO‐knockout mice developed more tumors and harbored larger tumor loads under treatment with azoxymethane and dextran sulfate sodium. Gene set enrichment analysis revealed that PTPRO downregulation was significantly associated with the fatty acid metabolism pathways. Blockage of fatty acid synthesis abrogated the effects of PTPRO silencing on cell growth and liver metastasis. Further experiments indicated that PTPRO silencing induced the activation of the AKT serine/threonine kinase (AKT)/mammalian target of rapamycin (mTOR) signaling axis, thus promoting de novo lipogenesis by enhancing the expression of sterol regulatory element‐binding protein 1 (SREBP1) and its target lipogenic enzyme acetyl‐CoA carboxylase alpha (ACC1) by activating the AKT/mTOR signaling pathway. Furthermore, PTPRO attenuation decreased the fatty acid oxidation rate by repressing the expression of peroxisome proliferator‐activated receptor alpha (PPARα) and its downstream enzyme peroxisomal acyl‐coenzyme A oxidase 1 (ACOX1) via activating the p38/extracellular signal‐regulated kinase (ERK) mitogen‐activated protein kinase (MAPK) signaling pathway. Conclusions PTPRO could suppress CRC development and metastasis via modulating the AKT/mTOR/SREBP1/ACC1 and MAPK/PPARα/ACOX1 pathways and reprogramming lipid metabolism.

Abstract Characterized by the expression of the critical transcription factor forkhead box protein P3, regulatory T (Treg) cells are an essential part of the immune system, with a dual effect on the pathogenesis of autoimmune diseases and cancer. Targeting Tregs to reestablish the proinflammatory and immunogenic tumor microenvironment (TME) is an increasingly attractive strategy for cancer treatment and has been emphasized in recent years. However, attempts have been significantly hindered by the subsequent autoimmunity after Treg ablation owing to systemic loss of their suppressive capacity. Cellular metabolic reprogramming is acknowledged as a hallmark of cancer, and emerging evidence suggests that elucidating the underlying mechanisms of how intratumoral Tregs acquire metabolic fitness and superior immunosuppression in the TME may contribute to clinical benefits. In this review, we discuss the common and distinct metabolic profiles of Tregs in peripheral tissues and the TME, as well as the differences between Tregs and other conventional T cells in their metabolic preferences. By focusing on the critical roles of different metabolic programs, such as glycolysis, oxidative phosphorylation, fatty acid oxidation, fatty acid synthesis, and amino acid metabolism, as well as their essential regulators in modulating Treg proliferation, migration, and function, we hope to provide new insights into Treg cell-targeted antitumor immunotherapies.

In the current study, we evaluated the effect of leucine-enkephalin (L-ENK) on lipid deposition and GSK-3β/mTOR signaling in zebrafish. Zebrafish were exposed with 2.5, 12.5, and 25 µg/g body weight (bw) L-ENK for four weeks. Our results demonstrated that 2.5, 12.5, and 25 µg/g L-ENK enhanced the hepatic gene expression and activities of fatty acid synthesis enzymes. The level of triglyceride (TG) and the number of lipid droplet was increased by 2.5, 12.5, and 25 µg/g L-ENK treatments. Moreover, 2.5, 12.5, and 25 µg/g L-ENK elevated mTOR and PPARγ gene expression, but inhibited GSK-3β and TSC2 expression in the zebrafish liver. Our results showed that L-ENK induces fatty acid synthesis and lipid deposition, and the signaling GSK-3β/mTOR may be involved in this regulatory process. [ABSTRACT FROM AUTHOR]

OBJECTIVE: This study aims to investigate the correlations between gene alterations induced in Mdr2-knockout (Mdr2-/-) models and liver fibrosis. SUBJECTS AND METHODS: The overlapping genes in Mdr2-/- models were determined and included in logistic regression analysis to identify potential candidates for predicting liver fibrosis. Correlations between the expression levels of the identified candidates and hepatic stellate cells (HSCs) were addressed. Functional enrichment of the identified candidates was also evaluated via bioinformatic analysis. RESULTS: Twenty-two overlapping genes in the GSE4612, GSE8642 and GSE14539 datasets were identified. Univariate and multivariate analysis indicated that ELOVL fatty acid elongase 7 (ELOVL7) was significantly associated with liver fibrosis S = 2 (OR = 11.8, 95% CI = 2.0 - 69.2, p = 0.006). ELOVL7 was significantly upregulated in patients with various types of liver injury including hepatitis B virus (HBV) infection and fatty liver diseases, and in multiple liver injury models, including bile duct ligation (BDL), carbon tetrachloride (CCl4) and paracetamol injection-induced liver damage models (all p < 0.05). The ELOVL7 levels were significantly higher in HSCs than in other liver cells (all p < 0.05) and were significantly upregulated in activated HSCs compared to quiescent HSCs (all p < 0.05). In addition, ELOVL7 expression was positively associated with transforming growth factor ß (TGFß) and bone morphogenic protein 9 (BMP9) expression and negatively associated with BMP7 expression. Bioinformatic analysis of functional enrichment indicated that ELOVL7 is mainly involved in fatty acid synthesis and metabolism. CONCLUSIONS: ELOVL7 could accurately predict advanced liver fibrosis. It might be involved in the activation of HSCs and the TGFß signaling pathway. [ABSTRACT FROM AUTHOR]

Metabolic adaptation is an emerging hallmark of tumors. De novo fatty acid synthesis is an important metabolic process to produce metabolic intermediates for energy storage, biosynthesis of membrane lipids and generation of signaling molecules. Acetyl-CoA carboxylase 1 (ACC1) is a critical enzyme in the fatty acid synthesis, which carboxylates acetyl-CoA carboxylic acid to form malonyl-CoA. The role of acetylCoA carboxylase 1 in fatty acid synthesis makes it a promising therapeutic target for various metabolic diseases such as non-alcoholic fatty liver disease, obesity and diabetes. Tumors have a high energy flow and a strong dependence on fatty acid synthesis. Thus, acetyl-CoA carboxylase inhibition has become a potential choice for anti-tumor therapy. In this review, we first introduced the structure and expression pattern of Acetyl-CoA carboxylase 1. We also discussed the molecular mechanisms of acetyl-CoA carboxylase 1 in the initiation and progression of various cancer types. Furthermore, acetyl-CoA carboxylase1 inhibitors has also been discussed. Collectively, we summarized the interplay between acetyl-CoA carboxylase 1 and tumorigenesis, indicating acetyl-CoA carboxylase 1 as a promising therapeutic target for tumor management. [ABSTRACT FROM AUTHOR]

Mitochondria are intracellular organelles located in the cytoplasm, that are essential for life and health. It is also known as the powerhouse of the cells and use a process called oxidative phosphorylation to generate energy. In side mitochondria, the lipid monomer fatty acids act as energy sources, membrane constituents, molecules for post translational modifications of proteins and cellular signaling factors. Plant cells possess couple of distinct type 2 Fatty Acid Synthase (FAS) systems. The two systems take place in plastids (ptFAS) and mitochondria (mtFAS). Lots of mtFAS components have been identified but, the physiological functions of mtFAS are still poorly understood. In this review, we have characterized five Arabidopsis mtFAS components, namely Mitochondrial β-Ketoacyl-ACP Synthase (mtKAS), Mitochondrial 3-Hydroxyacyl-ACP Dehydratase (mtHD), Mitochondrial Enoyl-ACP reductase (mtER), Mitochondrial Phosphopantetheinyl Transferase (mtPPT), and Mitochondrial Malonyl-CoA Synthetase (mtMCS). MtKAS, mtHD, and mtER catalyze 3 reactions of the 4 reactions of the acyl chain elongation cycle; mtPPT is responsible for activating Mitochondrial Acyl Carrier Protein (mtACP) by the addition of a phosphopantetheine cofactor; and mtMCS generates malonyl-CoA, the donor of 2-carbon elongation unit for the mtFAS system. Mitochondrial octanoyl-ACP is the precursor for the synthesis of lipoic acid, which is the coenzyme of the H-subunit of Glycine Decarboxylase Complex (GDC), a key enzyme of photorespiration. Accordingly, mutations in the mtFAS system can lead to a typical deficiency in photorespiration due to the depletion of the lipoylation of the H-subunit of GDC. These mutants are altered as an inferior effect of the deficiency in photorespiration. In addition, mutant analyses demonstrate that mitochondrial 3-hydroxymyristyl-ACP contributes to the biosynthesis of lipid alike molecules, suggesting a novel synthetic destination of the mtFAS intermediates. RNA-seq transcriptomic analyses of the mutants establish a regulatory network that is associated with the mtFAS functions is crucial for plant metabolic homeostasis. [ABSTRACT FROM AUTHOR]

Pathways that govern cellular bioenergetics are deregulated in tumor cells and represent a hallmark of cancer. Tumor cells have the capacity to reprogram pathways that control nutrient acquisition, anabolism and catabolism to enhance their growth and survival. Tumorigenesis requires the autonomous reprogramming of key metabolic pathways that obtain, generate and produce metabolites from a nutrient-deprived tumor microenvironment to meet the increased bioenergetic demands of cancer cells. Intra- and extracellular factors also have a profound effect on gene expression to drive metabolic pathway reprogramming in not only cancer cells but also surrounding cell types that contribute to anti-tumor immunity. Despite a vast amount of genetic and histologic heterogeneity within and between cancer types, a finite set of pathways are commonly deregulated to support anabolism, catabolism and redox balance. Multiple myeloma (MM) is the second most common hematologic malignancy in adults and remains incurable in the vast majority of patients. Genetic events and the hypoxic bone marrow milieu deregulate glycolysis, glutaminolysis and fatty acid synthesis in MM cells to promote their proliferation, survival, metastasis, drug resistance and evasion of immunosurveillance. Here, we discuss mechanisms that disrupt metabolic pathways in MM cells to support the development of therapeutic resistance and thwart the effects of anti-myeloma immunity. A better understanding of the events that reprogram metabolism in myeloma and immune cells may reveal unforeseen vulnerabilities and advance the rational design of drug cocktails that improve patient survival.

ABSTRACT Proper synthesis and maintenance of a multilayered cell envelope are critical for bacterial fitness. However, whether mechanisms exist to coordinate synthesis of the membrane and peptidoglycan layers is unclear. In Bacillus subtilis, synthesis of peptidoglycan (PG) during cell elongation is mediated by an elongasome complex acting in concert with class A penicillin-binding proteins (aPBPs). We previously described mutant strains limited in their capacity for PG synthesis due to a loss of aPBPs and an inability to compensate by upregulation of elongasome function. Growth of these PG-limited cells can be restored by suppressor mutations predicted to decrease membrane synthesis. One suppressor mutation leads to an altered function repressor, FapR*, that functions as a super-repressor and leads to decreased transcription of fatty acid synthesis (FAS) genes. Consistent with fatty acid limitation mitigating cell wall synthesis defects, inhibition of FAS by cerulenin also restored growth of PG-limited cells. Moreover, cerulenin can counteract the inhibitory effect of β-lactams in some strains. These results imply that limiting PG synthesis results in impaired growth, in part, due to an imbalance of PG and cell membrane synthesis and that B. subtilis lacks a robust physiological mechanism to reduce membrane synthesis when PG synthesis is impaired. IMPORTANCE Understanding how a bacterium coordinates cell envelope synthesis is essential to fully appreciate how bacteria grow, divide, and resist cell envelope stresses, such as β-lactam antibiotics. Balanced synthesis of the peptidoglycan cell wall and the cell membrane is critical for cells to maintain shape and turgor pressure and to resist external cell envelope threats. Using Bacillus subtilis, we show that cells deficient in peptidoglycan synthesis can be rescued by compensatory mutations that decrease the synthesis of fatty acids. Further, we show that inhibiting fatty acid synthesis with cerulenin is sufficient to restore growth of cells deficient in peptidoglycan synthesis. Understanding the coordination of cell wall and membrane synthesis may provide insights relevant to antimicrobial treatment.

The world’s population is projected to increase by two billion by 2050, resulting in food and energy insecurity. Oilseed crops have been identified as key to address these challenges: they produce and store lipids in the seeds as triacylglycerols that can serve as a source of food/feed, renewable fuels, and other industrially-relevant chemicals. Therefore, improving seed oil content and composition has generated immense interest. Research efforts aiming to unravel the regulatory pathways involved in fatty acid synthesis and to identify targets for metabolic engineering have made tremendous progress. This review provides a summary of the current knowledge of oil metabolism and discusses how photochemical activity and unconventional pathways can contribute to high carbon conversion efficiency in seeds. It also highlights the importance of 13C-metabolic flux analysis as a tool to gain insights on the pathways that regulate oil biosynthesis in seeds. Finally, a list of key genes and regulators that have been recently targeted to enhance seed oil production are reviewed and additional possible targets in the metabolic pathways are proposed to achieve desirable oil content and quality [ABSTRACT FROM AUTHOR]

The present study tested the hypothesis that dietary insect meal from Hermetia illucens (HI) larvae attenuates the development of liver steatosis and hyperlipidemia in the obese Zucker rat. To test the hypothesis, a 4-week trial with male, obese Zucker rats (n = 30) and male, lean Zucker rats (n = 10) was performed. The obese rats were assigned to three obese groups (group O-C, group O-HI25, group O-HI50) of 10 rats each. The lean rats served as a lean control group (L-C). Group L-C and group O-C were fed a control diet with 20% casein as protein source, whereas 25% and 50% of the protein from casein was replaced with protein from HI larvae meal in the diets of group O-HI25 and O-HI50, respectively. The staining of liver sections with Oil red O revealed an excessive lipid accumulation in the liver of group O-C compared to group L-C, whereas liver lipid accumulation in group O-HI25 and O-HI50 was markedly reduced compared to group O-C. Hepatic concentrations of triglycerides, cholesterol, C14:0, C16:0, C16:1, C18:0, C18:1, the sum of total fatty acids and hepatic mRNA levels of several genes associated with lipid synthesis and plasma concentration of cholesterol were markedly higher in group O-C than in group L-C, but lower in group O-HI50 than in group O-C (p < 0.05). In conclusion, partial replacement of casein by HI larvae meal attenuates liver steatosis and dyslipidemia in obese Zucker rats. This suggests that HI larvae meal serves as a functional food protecting from obesity-induced metabolic disorders. [ABSTRACT FROM AUTHOR]