Physiological and nutritional regulation of enzymes of triacylglycerol synthesis

Traditional Chinese medicine and plant-derived natural products in regulating triglyceride metabolism: Mechanisms and therapeutic potential

The incidence of cardiometabolic disease is increasing globally, with a trend toward younger age of onset. Among these, atherosclerotic cardiovascular disease is a leading cause of mortality worldwide. Despite the efficacy of traditional lipid-lowering drugs, such as statins, in reducing low-density lipoprotein cholesterol levels, a significant residual risk of cardiovascular events remains, which is closely related to unmet triglyceride (TG) targets. The clinical application of current TG-lowering Western medicines has certain limitations, necessitating alternative or complementary therapeutic strategies. Traditional Chinese medicine (TCM) and plant-derived natural products, known for their safety owing to their natural origins and diverse biological activities, offer promising avenues for TG regulation with potentially fewer side effects. This review systematically summarises the mechanisms of TG metabolism and subsequently reviews the regulatory effects of TCM and plant-derived natural products on TG metabolism, including the inhibition of TG synthesis (via endogenous and exogenous pathways), promotion of TG catabolism, regulation of fatty acid absorption and transport, enhancement of lipophagy, modulation of the gut microbiota, and other mechanisms. In conclusion, through a comprehensive analysis of recent studies, this review consolidates the multifaceted regulatory roles of TCM and plant-derived natural products in TG metabolism and elucidates their potential as safer, multi-target therapeutic agents in managing hypertriglyceridemia and mitigating cardiovascular risk, thereby providing a basis for new drug development.

Silencing NlFAR7 destroyed the pore canals and related structures of the brown planthopper

Fatty acyl-CoA reductase (FAR) is one of the key enzymes, which catalyses the conversion of fatty acyl-CoA to the corresponding alcohols. Among the FAR family members in the brown planthopper (Nilaparvata lugens), NlFAR7 plays a pivotal role in both the synthesis of cuticular hydrocarbons and the waterproofing of the cuticle. However, the precise mechanism by which NlFAR7 influences the formation of the cuticle structure in N. lugens remains unclear. Therefore, this paper aims to investigate the impact of NlFAR7 through RNA interference, transmission electron microscope, focused ion beam scanning electron microscopy (FIB-SEM) and lipidomics analysis. FIB-SEM is employed to reconstruct the three-dimensional (3D) architecture of the pore canals and related cuticle structures in N. lugens subjected to dsNlFAR7 and dsGFP treatments, enabling a comprehensive assessment of changes in the cuticle structures. The results reveal a reduction in the thickness of the cuticle and disruptions in the spiral structure of pore canals, accompanied by widened base and middle diameters. Furthermore, the lipidomics comparison analysis between dsNlFAR7- and dsGFP-treated N. lugens demonstrated that there were 25 metabolites involved in cuticular lipid layer synthesis, including 7 triacylglycerols (TGs), 5 phosphatidylcholines (PCs), 3 phosphatidylethanolamines (PEs) and 2 diacylglycerols (DGs) decreased, and 4 triacylglycerols (TGs) and 4 PEs increased. In conclusion, silencing NlFAR7 disrupts the synthesis of overall lipids and destroys the cuticular pore canals and related structures, thereby disrupting the secretion of cuticular lipids, thus affecting the cuticular waterproofing of N. lugens. These findings give significant attention with reference to further biochemical researches on the substrate specificity of FAR protein, and the molecular regulation mechanisms during N. lugens life cycle.

From tissue lesions to neurotoxicity: The devastating effects of small-sized nanoplastics on red drum Sciaenops ocellatus

Nanoplastic pollution typically exhibits more biotoxicity to marine organisms than microplastic pollution. Limited research exists on the toxic effects of small-sized nanoplastics on marine fish, especially regarding their post-exposure resilience. In this study, red drum (Sciaenops ocellatus) were exposed to small-sized polystyrene nanoplastics (30 nm, PS-NPs) for 7 days for the exposure experiments, followed by 14 days of recovery experiments. Histologically, hepatic lipid droplets and branchial epithelial liftings were the primary lesions induced by PS-NPs during both exposure and recovery periods. The inhibition of total superoxide dismutase activity and the accumulation of malondialdehyde content throughout the exposure and recovery periods. Transcriptional and metabolic regulation revealed that PS-NPs induced lipid metabolism disorders and DNA damage during the initial 1-2 days of exposure periods, followed by immune responses and neurotoxicity in the later stages (4-7 days). During the early recovery stages (2-7 days), lipid metabolism and cell cycle were activated, while in the later recovery stage (14 days), the emphasis shifted to lipid metabolism and energy metabolism. Persistent histological lesions, changes in antioxidant capacity, and fluctuations in gene and metabolite expression were observed even after 14 days of recovery periods, highlighting the severe biotoxicity of small-sized PS-NPs to marine fish. In summary, small-sized PS-NPs have severe biotoxicity, causing tissue lesions, oxidative damage, lipid metabolism disorders, DNA damage, immune responses, and neurotoxicity in red drum. This study offers valuable insights into the toxic effects and resilience of small-sized nanoplastics on marine fish.

Differential reliance of CTD-nuclear envelope phosphatase 1 on its regulatory subunit in ER lipid synthesis and storage

Lipin 1 is an ER enzyme that produces diacylglycerol, the lipid intermediate that feeds into the synthesis of glycerophospholipids for membrane expansion or triacylglycerol for storage into lipid droplets. CTD-Nuclear Envelope Phosphatase 1 (CTDNEP1) regulates lipin 1 to restrict ER membrane synthesis, but a role for CTDNEP1 in lipid storage in mammalian cells is not known. Furthermore, how NEP1R1, the regulatory subunit of CTDNEP1, contributes to these functions in mammalian cells is not fully understood. Here, we show that CTDNEP1 is reliant on NEP1R1 for its stability and function in limiting ER expansion. CTDNEP1 contains an amphipathic helix at its N-terminus that targets to the ER, nuclear envelope and lipid droplets. We identify key residues at the binding interface of CTDNEP1 and NEP1R1 and show that they facilitate complex formation in vivo and in vitro. We demonstrate that NEP1R1 binding to CTDNEP1 shields CTDNEP1 from proteasomal degradation to regulate lipin 1 and restrict ER size. Unexpectedly, NEP1R1 was not required for CTDNEP1's role in restricting lipid droplet biogenesis. Thus, the reliance of CTDNEP1 function on NEP1R1 depends on cellular demands for membrane production versus lipid storage. Together, our work provides a framework into understanding how the ER regulates lipid synthesis under different metabolic conditions.

Proteome Analysis Related to Unsaturated Fatty Acid Synthesis by Interfering with Bovine Adipocyte ACSL1 Gene

Unsaturated fatty acids (UFAs) in beef play a vital role in promoting human health. Long-chain fatty acyl-CoA synthase 1 (ACSL1) is a crucial gene for UFA synthesis in bovine adipocytes. To investigate the protein expression profile during UFA synthesis, we performed a proteomic analysis of bovine adipocytes by RNA interference and non-interference with ACSL1 using label-free techniques. A total of 3558 proteins were identified in both the NC and si-treated groups, of which 1428 were differentially expressed proteins (DEPs; fold change ≥ 1.2 or ≤ 0.83 and p-value < 0.05). The enrichment analysis of the DEPs revealed signaling pathways related to UFA synthesis or metabolism, including cAMP, oxytocin, fatty acid degradation, glycerol metabolism, insulin, and the regulation of lipolysis in adipocytes (p-value < 0.05). Furthermore, based on the enrichment analysis of the DEPs, we screened 50 DEPs that potentially influence the synthesis of UFAs and constructed an interaction network. Moreover, by integrating our previously published transcriptome data, this study established a regulatory network involving differentially expressed long non-coding RNAs (DELs), highlighting 21 DEPs and 13 DELs as key genes involved in UFA synthesis. These findings present potential candidate genes for further investigation into the molecular mechanisms underlying UFA synthesis in bovines, thereby offering insights to enhance the quality of beef and contribute to consumer health in future studies.

Platelet-Derived Microvesicles Mediate Cardiomyocyte Ferroptosis by Transferring ACSL1 During Acute Myocardial Infarction

Acute myocardial infarction (AMI) is one of the critical health conditions often caused by the rupture of unstable coronary artery plaque, triggering a series of events, such as platelet activation, thrombus formation, coronary artery blockage, lasted severe ischemia, and hypoxia in cardiomyocytes, and culminating in cell death. Platelet-derived microvesicles (PMVs) act as intermediates for cellular communication. Nevertheless, the role of PMVs in myocardial infarction remains unclear. Initially, AMI-related messenger ribose nucleic acid (mRNA) and micro RNA (miRNA) datasets from the Gene Expression Omnibus (GEO) database were analyzed, specifically focusing on the expressed genes associated with Ferroptosis. Further, a miRNA-mRNA regulatory network specific to AMI was constructed. Then, the effect of PMVs on cardiomyocyte survival was further confirmed through in vitro experiments. High ACSL1 expression was observed in the platelets of AMI patients. The gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that ACSL1, located in the mitochondria, played a key role in the PPAR signaling pathway. The elevated ACSL1 expression in a co-culture model of PMVs and AC16 cardiomyocytes significantly increased the AC16 cell Ferroptosis. Further, we validated that the platelet ACSL1 expression could be regulated by hsa-miR-449a. Together, these findings suggested that platelet ACSL1 could trigger myocardial cell death via PMV transport. In addition, this research provided a theoretical framework for attenuating myocardial cell Ferroptosis in patients with acute myocardial infarction.

A lipid index for risk of hyperlipidemia caused by anti-retroviral drugs

HIV-associated lipodystrophy has been reported in people taking anti-retroviral therapy (ART). Lipodystrophy can cause cardiovascular diseases, affecting the quality of life of HIV-infected individuals. In this study, we propose a pharmacological lipid index to estimate the risk of hyperlipidemia caused by anti-retroviral drugs. Lipid droplets were stained in cells treated with anti-retroviral drugs and cyclosporin A. Signal intensities of lipid droplets were plotted against the drug concentrations to obtain an isodose of 10 μM of cyclosporin A, which we call the Pharmacological Lipid Index (PLI). The PLI was then normalized by EC50. PLI/EC50 values were low in early proteinase inhibitors and the nucleoside reverse transcriptase inhibitor, d4T, indicating high risk of hyperlipidemia, which is consistent with previous findings of hyperlipidemia. In contrast, there are few reports of hyperlipidemia for drugs with high PLI/EC50 scores. Data suggests that PLI/EC50 is a useful index for estimating the risk of hyperlipidemia.

Lysophospholipid acyltransferases orchestrate the compositional diversity of phospholipids

Lysophospholipid acyltransferases (LPLATs), in concert with glycerol-3-phosphate acyltransferases (GPATs) and phospholipase A1/2s, orchestrate the compositional diversity of the fatty chains in membrane phospholipids. Fourteen LPLAT enzymes which come from two distinct families, AGPAT and MBOAT, have been identified, and in this mini-review we provide an overview of their roles in de novo and remodeling pathways of membrane phospholipid biosynthesis. Recently new nomenclature for LPLATs has been introduced (LPLATx, where x is a number 1-14), and we also give an overview of key biological functions that have been discovered for LPLAT1-14, revealed primarily through studies of LPLAT-gene-deficient mice as well as by linkages to various human diseases.

Chitobiose exhibited a lipid-lowering effect in ob/ob-/- mice via butyric acid enrolled liver-gut crosstalk

Chitobiose (COS2) efficiently lowers lipids in vivo and facilitates butyric acid enrichment during human fecal fermentation. However, whether COS2 can interact with butyric acid to generate a hypolipidemic effect remains unclear. This study examined the hypolipidemic mechanism of COS2 involving butyric acid, which could alleviate non-alcoholic fatty liver disease (NAFLD). The results revealed that COS2 administration modulated the β-oxidation pathway in the liver and restructured the short chain fatty acids in the fecal of ob/ob-/- mice. Moreover, the hypolipidemic effect of COS2 and its specific accumulated metabolite butyric acid was verified in sodium oleate-induced HepG2 cells. Butyric acid was more effective to reverse lipid accumulation and up-regulate β-oxidation pathway at lower concentrations. Furthermore, structural analysis suggested that butyric acid formed hydrogen bonds with key residues in hydrophilic ligand binding domains (LBDs) of PPARα and activated the transcriptional activity of the receptor. Therefore, the potential mechanism behind the lipid-lowering effect of COS2 in vivo involved restoring hepatic lipid disorders via butyric acid accumulation and liver-gut axis signaling.

Gene Variants Implicated in Steatotic Liver Disease: Opportunities for Diagnostics and Therapeutics

Non-alcoholic fatty liver disease (NAFLD) describes a steatotic (or fatty) liver occurring as a consequence of a combination of metabolic, environmental, and genetic factors, in the absence of significant alcohol consumption and other liver diseases. NAFLD is a spectrum of conditions. Steatosis in the absence of inflammation is relatively benign, but the disease can progress into more severe forms like non-alcoholic steatohepatitis (NASH), liver cirrhosis, and hepatocellular carcinoma. NAFLD onset and progression are complex, as it is affected by many risk factors. The interaction between genetic predisposition and other factors partially explains the large variability of NAFLD phenotype and natural history. Numerous genes and variants have been identified through large-scale genome-wide association studies (GWAS) that are associated with NAFLD and one or more subtypes of the disease. Among them, the largest effect size and most consistent association have been patatin-like phospholipase domain-containing protein 3 (PNPLA3), transmembrane 6 superfamily member 2 (TM6SF2), and membrane-bound O-acyltransferase domain containing 7 (MBOAT7) genes. Extensive in vitro and in vivo studies have been conducted on these variants to validate these associations. The focus of this review is to highlight the genetics underpinning the molecular mechanisms driving the onset and progression of NAFLD and how they could potentially be used to improve genetic-based diagnostic testing of the disease and develop personalized, targeted therapeutics.

Differential reliance of CTD-nuclear envelope phosphatase 1 on its regulatory subunit in ER lipid synthesis and storage

The endoplasmic reticulum (ER) is the site for the synthesis of the major membrane and storage lipids. Lipin 1 produces diacylglycerol, the lipid intermediate critical for the synthesis of both membrane and storage lipids in the ER. CTD-Nuclear Envelope Phosphatase 1 (CTDNEP1) regulates lipin 1 to restrict ER membrane synthesis, but its role in lipid storage in mammalian cells is unknown. Here, we show that the ubiquitin-proteasome degradation pathway controls the levels of ER/nuclear envelope-associated CTDNEP1 to regulate ER membrane synthesis through lipin 1. The N-terminus of CTDNEP1 is an amphipathic helix that targets to the ER, nuclear envelope and lipid droplets. We identify key residues at the binding interface of CTDNEP1 with its regulatory subunit NEP1R1 and show that they facilitate complex formation in vivo and in vitro . We demonstrate a role for NEP1R1 in temporarily shielding CTDNEP1 from proteasomal degradation to regulate lipin 1 and restrict ER size. Unexpectedly, we found that NEP1R1 is not required for CTDNEP1's role in restricting lipid droplet biogenesis. Thus, the reliance of CTDNEP1 function on its regulatory subunit differs during ER membrane synthesis and lipid storage. Together, our work provides a framework into understanding how the ER regulates lipid synthesis and storage under fluctuating conditions.

Comprehensive review on the pathogenesis of hypertriglyceridaemia-associated acute pancreatitis

It is well known, that the inflammatory process that characterizes acute pancreatitis (AP) can lead to both pancreatic damage and systemic inflammatory response syndrome (SIRS). During the last 20 years, there has been a growing incidence of episodes of acute pancreatitis associated with hypertriglyceridaemia (HTAP). This review provides an overview of triglyceride metabolism and the potential mechanisms that may contribute to developing or exacerbating HTAP. The article comprehensively discusses the various pathological roles of free fatty acid, inflammatory response mechanisms, the involvement of microcirculation, serum calcium overload, oxidative stress and the endoplasmic reticulum, genetic polymorphism, and gut microbiota, which are known to trigger or escalate this condition. Future perspectives on HTAP appear promising, with ongoing research focused on developing more specific and effective treatment strategies.

Glycyrrhizic acid glycosides reduces extensive tripterygium glycosides-induced lipid deposition in hepatocytes

Aim

Tripterygium glycosides (TG) extracted from the plant Tripterygium wilfordii Hook F has been used to treat chronic kidney diseases for many years. However, hepatotoxicity limits its clinical application. Glycyrrhizic acid glycosides (GA) can reduce TG hepatotoxicity, however, further investigation into the underlying molecular mechanisms by which GA attenuates TG-induced hepatotoxicity is required.

Methods

Sprague‒Dawley rats were randomly divided into the control group, the TG groups (TG189 mg/kg group, TG472.5 mg/kg group), and the TG + GA groups (TG189 mg/kg + GA20.25 mg/kg group, TG472.5 mg/kg + GA20.25 mg/kg group). After 21 consecutive days of intragastric administration, structural and molecular changes in hepatocytes were detected.

Results

After 21 days of TG treatment, the serum level of the total bilirubin, triglyceride, total cholesterol, and low-density lipoprotein cholesterol increased in the TG189 mg/kg and TG472.5 mg/kg groups when compared to the control group. High-density lipoprotein cholesterol levels were reduced in both TG groups. The ultrastructure of hepatocytes and the structural integrity of the liver were compromised. In addition, the relevant molecular level of the peroxisome proliferators-activated receptor α (PPARα) and acyl-CoA synthetase long-chain family members (ACSLs) pathway was modulated. With the addition of 20.25 mg/kg GA, the serum biochemical indexes and liver tissue structure ultrastructure of hepatocytes were improved, and the PPARα-ACSLs pathway was corrected.

Conclusion

The combined application of GA and TG improved abnormal lipid metabolism, repaired liver structure, reduced lipid deposition in hepatocytes, and reduced TG-induced hepatotoxicity.

Insulin Regulation of Hepatic Lipid Homeostasis

The incidence of obesity, insulin resistance, and type II diabetes (T2DM) continues to rise worldwide. The liver is a central insulin-responsive metabolic organ that governs whole-body metabolic homeostasis. Therefore, defining the mechanisms underlying insulin action in the liver is essential to our understanding of the pathogenesis of insulin resistance. During periods of fasting, the liver catabolizes fatty acids and stored glycogen to meet the metabolic demands of the body. In postprandial conditions, insulin signals to the liver to store excess nutrients into triglycerides, cholesterol, and glycogen. In insulin-resistant states, such as T2DM, hepatic insulin signaling continues to promote lipid synthesis but fails to suppress glucose production, leading to hypertriglyceridemia and hyperglycemia. Insulin resistance is associated with the development of metabolic disorders such as cardiovascular and kidney disease, atherosclerosis, stroke, and cancer. Of note, nonalcoholic fatty liver disease (NAFLD), a spectrum of diseases encompassing fatty liver, inflammation, fibrosis, and cirrhosis, is linked to abnormalities in insulin-mediated lipid metabolism. Therefore, understanding the role of insulin signaling under normal and pathologic states may provide insights into preventative and therapeutic opportunities for the treatment of metabolic diseases. Here, we provide a review of the field of hepatic insulin signaling and lipid regulation, including providing historical context, detailed molecular mechanisms, and address gaps in our understanding of hepatic lipid regulation and the derangements under insulin-resistant conditions. © 2023 American Physiological Society. Compr Physiol 13:4785-4809, 2023.

Circulating metabolomic and lipidomic changes in subjects with new-onset type 1 diabetes after optimization of glycemic control

AIMS

To uncover novel candidate metabolomic and lipidomic biomarkers in newly-diagnosed type 1 diabetes (T1DM) after achieving optimal glucose control.

METHODS

Comprehensive lipidomic and metabolomic analysis was performed in serum of 12 adults with T1DM at onset and after achieving optimal glycemic control (HbA1c < 7 %) (after 2-6 months).

RESULTS

After intensive therapy, subjects (mean age 25.2 years, 58.3 % men) showed decreases in blood glucose (p < 0.001), HbA1c [11.5 % (9.2-13.4) to 6.2 % (5.2 - 6.7); p < 0.001] and changes in 51 identified lipids. Among these changes, we found that triglycerides (TG) containing medium chain fatty acids (TG45:0, TG47:1), sphingomyelins (SM) (SM(d18:2/20:0), SM42:4)), and phosphatidylcholines (PC) (PC(O-26:2), PC(O-30:0), PC(O-32:0), PC(O-42:6), PC(O-44:5), PC(O-38:3), PC(O-33:0), PC(O-46:8), PC(O-44:6), PC(O-40:3), PC(O-42:4), PC(O-46:7), PC(O-46:6), PC(O-44:5), PC(O-42:3), PC(O-44:4)) decreased; whereas PC(35:1), PC(37:1) and TG containing longer chain fatty acids (TG(52:1), TG(55:7), TG(51:2), TG(53:3), TG52:2), TG(53:2), TG(57:3), TG(61:3), TG(61:2) increased. Further, dihydro O-acylceramide (18:1/18:0/16:0), diacylglycerophosphoethanolamine (PE(34:1)), diacylglycerophosphoinositol (PI(38:6), and dihydrosphingomyelins (dihydroSM(36:0), dihydroSM(40:0), dihydroSM(41:0), dihydroSM(42:0)) increased. Uric acid, mannitol, and mannitol-1-acetate levels also increased.

CONCLUSIONS

Our data uncovered potential favorable changes in the metabolism of glycerophospholipids, glycerolipids, and sphingolipids in new-onset T1DM after achieving optimal glycemic control. Further research on their potential role in developing diabetes-related complications is needed.

Function of the Polyketide Synthase Domains of Schizochytrium sp. on Fatty Acid Synthesis in Yarrowia lipolytica

It is well known that polyunsaturated fatty acids (PUFAs) in Schizochytrium sp. are mainly synthesized via the polyketide synthase (PKS) pathway. However, the specific mechanism of PKS in fatty acid synthesis is still unclear. In this work, the functions of ORFA, ORFB, ORFC, and their individual functional domain genes on fatty acid synthesis were investigated through heterologous expression in Yarrowia lipolytica. The results showed that the expression of ORFA, ORFB, ORFC, and their individual functional domains all led to the increase of the very long-chain PUFA content (mainly eicosapentaenoic acid). Furthermore, the transcriptomic analysis showed that except for the 3-ketoacyl-ACP synthase (KS) domain of ORFB, the expression of an individual functional domain, including malonyl-CoA: ACP acyltransferase, 3-hydroxyacyl-ACP dehydratase (DH), 3-ketoacyl-ACP reductase, and KS domains of ORFA, acyltransferase domains of ORFB, and two DH domains of ORFC resulted in upregulation of the tricarboxylic acid cycle and pentose phosphate pathway, downregulation of the triacylglycerol biosynthesis, fatty acid synthesis pathway, and β-oxidation in Yarrowia lipolytica. These results provide a theoretical basis for revealing the function of PKS in fatty acid synthesis in Y. lipolytica and elucidate the possible mechanism for PUFA biosynthesis.

Pregnancy Toxemia in Ewes: A Review of Molecular Metabolic Mechanisms and Management Strategies

Pregnancy toxemia is a nutritional metabolic disease during late gestation in small ruminants. The condition is characterized by disorders in carbohydrate and fat metabolism. Obese and multiparous ewes are particularly susceptible to pregnancy toxemia, which may lead to maternal death, abortion, or premature birth. Highly productive multiparous meat ewes are major breeding animals, which has led to an increased incidence of the disease. However, the pathogenesis of pregnancy toxemia remains unclear and adequate disease prevention and treatment strategies are absent. Investigating the pathogenesis of pregnancy toxemia, especially the metabolic pathways of hepatic lipids, is key to an improved understanding of the condition. This review provides a snapshot of the genes that are associated with lipid metabolism in the ovine liver, including genes involved in fatty acid oxidation, acetyl coenzyme metabolism, and triglyceride synthesis; describes the interrelationships between these genes; and summarizes the diagnosis, prevention, and treatment of pregnancy toxemia.

ACSL1 promotes imatinib-induced chronic myeloid leukemia cell senescence by regulating SIRT1/p53/p21 pathway

Although tyrosine kinase inhibitors (TKIs) improve the prognosis of chronic myeloid leukemia (CML) patients, resistance to TKIs and residual leukemia stem cells (LSCs) inevitably become the bottleneck of cure. Therefore, we need to explore novel treatment strategies based on conventional treatment strategies. Our previous study found that CML cell senescence may be one of the main factors to achieve clinical cure of CML. Studies have shown that lipid metabolism plays a key role in cellular senescence. Here, we found that long-chain acyl-CoA synthetase 1 (ACSL1) was significantly up-regulated in senescent CML cells. Furthermore, we demonstrated that overexpression of ACSL1 induces senescence and inhibits cell growth in K562 cells by altering cell cycle progression, and enhances the proliferation-inhibiting effect of imatinib. Overexpression of ACSL1 enhances imatinib-induced tumorigenic decline in K562 cells in vivo. Knockdown of ACSL1 reverses imatinib-induced senescence in K562 cells. Mechanistically, overexpression of ACSL1 induced senescence in K562 cells via the SIRT1/p53/p21 axis. Collectively, our study showed that ACSL1 promotes imatinib-induced K562 cells senescence and tumor growth by regulating SIRT1/p53/p21 pathway. The ACSL1/SIRT1/p53 signal axis is a novel mechanism of cell senescence in CML and a new potential target for eradication of CML LSCs.

A proteomics approach reveals digestive and nutritional responses to food intake in anadromous Coilia nasus

The estuarine tapertail anchovy, Coilia nasus, is an anadromous fish that undertakes over a 600-km spawning migration along the Yangtze River of China. They generally cease feeding during this process, but we recently documented that a small proportion of them appear to feed. Research on proteomic responses is essential for understanding the phenomenon of C. nasus feeding. In this study, we used an iTRAQ-based proteomics approach to study the changes in protein expression in response to food intake in C. nasus following voluntary fasting. Coilia nasus in the feeding group (CSI) were fed shrimp or small fish, whereas those in the control group (CSN) were starved. We identified 3279 proteins in the gastric tissue/stomach, of which 279 were significantly differentially expressed. In all, 133 differentially expressed proteins (DEPs) were upregulated and 146 proteins were downregulated in CSI compared with those in CSN C. nasus. In addition to gastric acid secretion caused by gastric distention, a functional analysis suggested that a series of DEPs were involved mainly in the regulation of protein digestion (e.g., carboxypeptidase A1 and chymotrypsin A-like), immune response (e.g., lysozyme and alpha 2-macroglobulin), and nutrition metabolism (e.g., glyceraldehyde 3-phosphate dehydrogenase, glycogenin, long-chain acyl-CoA synthetase, and creatine kinase). Real-time PCR confirmed that the mRNA levels of the DEPs were similar those obtained using iTRAQ. These results indicate that the nutrients obtained through food were effectively utilized by C. nasus, thereby providing energy for swimming, gonadal maturation, primary metabolism, and an enhanced immune function to better resist pathogen interference. This research contributes to the elucidation of nutritional regulation mechanisms of C. nasus to better protect the wild population.

Palmitate Potentiates Lipopolysaccharide-Induced IL-6 Production via Coordinated Acetylation of H3K9/H3K18, p300, and RNA Polymerase II

IL-6 is elevated in obese individuals and participates in the metabolic dysfunction associated with that condition. However, the mechanisms that promote IL-6 expression in obesity are incompletely understood. Because elevated levels of palmitate and LPS have been reported in obesity, we investigated whether these agents interact to potentiate IL-6 production. In this study, we report that LPS induces higher levels of IL-6 in human monocytes in the presence of palmitate. Notably, the priming effect of palmitate is associated with enhanced p300 binding and transcription factor recruitment to Il6 promoter regions. Gene silencing of p300 blocks this action of palmitate. RNA polymerase II recruitment was also enhanced at the Il6 promoter in palmitate/LPS-exposed cells. Acetylation levels of H3K9 and H3K18 were increased in monocytes treated with palmitate. Moreover, LPS stimulation of palmitate-treated cells led to increased levels of the transcriptionally permissive acetylation marks H3K9/H3K18 in the Il6 promoter compared with LPS alone. The effect of palmitate on LPS-induced IL-6 production was suppressed by the inhibition of histone acetyltransferases. Conversely, histone deacetylase inhibitors trichostatin A or sodium butyrate can substitute for palmitate in IL-6 production. Esterification of palmitate with CoA was involved, whereas β-oxidation and ceramide biosynthesis were not required, for the induction of IL-6 and H3K9/H3K18 acetylation. Monocytes of obese individuals showed significantly higher H3K9/H3K18 acetylation and Il6 expression. Overall, our findings support a model in which increased levels of palmitate in obesity create a setting for LPS to potentiate IL-6 production via chromatin remodeling, enabling palmitate to contribute to metabolic inflammation.

Adaptation to short-term extreme fat consumption alters intestinal lipid handling in male and female mice

The small intestine is a highly adaptable organ serving as both a barrier to the external environment and a conduit for nutrient absorption. Enterocytes package dietary triglycerides (TG) into chylomicrons for transport into circulation; the remaining TGs are stored in cytosolic lipid droplets (CLDs). The current study aimed to characterize the impact of diet composition on intestinal lipid handling in male and female wild-type mice. Mice were continued on their grain-based diet (GBD) and switched to a high-fat, high cholesterol Western-style diet (WD) or a ketogenic diet (KD) for 3 or 5 weeks. KD-fed mice displayed significantly higher plasma TG levels in response to an olive oil gavage than WD- and GBD-fed mice; TG levels were ~2-fold higher in male KD-fed mice than female KD-fed mice. Poloxamer-407 experiments revealed enhanced intestinal-TG secretion rates in male mice fed a KD upon olive oil gavage, whereas secretion rates were unchanged in female mice. Surprisingly, jejunal CLD size and TG mass after oil gavage were similar among the groups. At fasting, TG mass was significantly higher in the jejunum of male KD-fed mice and the duodenum of female KD-fed mice, providing increased substrate for chylomicron formation. In addition to greater fasting intestinal TG stores, KD-fed male mice displayed longer small intestinal lengths, while female mice displayed markedly longer jejunal villi lengths. After 5 week of diet, 12 h fasting-2 h refeeding experiments revealed jejunal TG levels were similar between diet groups in male mice; however, in female mice, jejunal TG mass was significantly higher in KD-fed mice compared to GBD- and WD-fed mice. These experiments reveal that KD feeding promotes distinct morphological and functional changes to the small intestine compared to the WD diet. Moreover, changes to intestinal lipid handling in response to carbohydrate and protein restriction manifest differently in male and female mice.

Comparing Transcriptomes Reveals Key Metabolic Mechanisms in Superior Growth Performance Nile Tilapia (Oreochromis niloticus)

Metabolic capacity is intrinsic to growth performance. To investigate superior growth performance in Nile tilapia, three full-sib families were bred and compared at the biochemical and transcriptome levels to determine metabolic mechanisms involved in significant growth differences between individuals under the same culture environment and feeding regime. Biochemical analysis showed that individuals in the higher growth group had significantly higher total protein, total triglyceride, total cholesterol, and high- and low-density lipoproteins, but significantly lower glucose, as compared with individuals in the lower growth group. Comparative transcriptome analysis showed 536 differentially expressed genes (DEGs) were upregulated, and 622 DEGs were downregulated. These genes were significantly enriched in three key pathways: the tricarboxylic acid cycle (TCA cycle), fatty acid biosynthesis and metabolism, and cholesterol biosynthesis and metabolism. Conjoint analysis of these key pathways and the biochemical parameters suggests that Nile tilapia with superior growth performance have higher ability to consume energy substrates (e.g., glucose), as well as higher ability to biosynthesize fatty acids and cholesterol. Additionally, the fatty acids biosynthesized by the superior growth performance individuals were less active in the catabolic pathway overall, but were more active in the anabolic pathway, and might be used for triglyceride biosynthesis to store excess energy in the form of fat. Furthermore, the tilapia with superior growth performance had lower ability to convert cholesterol into bile acids, but higher ability to convert it into sterols. We discuss the molecular mechanisms of the three key metabolic pathways, map the pathways, and note key factors that may impact the growth of Nile tilapia. The results provide an important guide for the artificial selection and quality enhancement of superior growth performance in tilapia.

Transcriptomic and Metabolomic Analysis Unravels the Molecular Regulatory Mechanism of Fatty Acid Biosynthesis in Styrax tonkinensis Seeds under Methyl Jasmonate Treatment

As the germ of a highly productive oil tree species, Styrax tonkinensis seeds have great potential to produce biodiesel and they have marvelous fatty acid (FA) composition. In order to explore the molecular regulatory mechanism of FA biosynthesis in S. tonkinensis seeds after methyl jasmonate (MJ) application, transcriptomic and metabolomic techniques were adopted so as to dissect the genes that are related to FA biosynthesis and their expression levels, as well as to discover the major FA concentration and composition. The results revealed that 200 μmol/L of MJ (MJ200) increased the crude fat (CF) mass fraction and generated the greatest impact on CF accumulation at 70 days after flowering. Twenty FAs were identified, among which palmitic acid, oleic acid, linoleic acid and linolenic acid were the major FAs, and the presence of MJ200 affected their concentrations variously. MJ200 could enhance FA accumulation through elevating the activity of enzymes that are related to FA synthesis. The number of differentially expressed genes increased with the seeds’ development in general. Fatty acid biosynthesis, the biosynthesis of unsaturated fatty acid, fatty acid elongation and glycerolipid metabolism were the main lipid metabolism pathways that were found to be involved. The changes in the expression levels of EAR, KAR, accA, accB and SAD2 were consistent with the changes in the CF mass fraction, indicating that they are important genes in the FA biosynthesis of S. tonkinensis seeds and that MJ200 promoted their expression levels. In addition, bZIP (which was screened by weighted correlation network analysis) also created significant impacts on FA biosynthesis. Our research has provided a basis for further studies on FA biosynthesis that is regulated by MJ200 at the molecular level and has helped to clarify the functions of key genes in the FA metabolic pathway in S. tonkinensis seeds.

CYP311A1 in the anterior midgut is involved in lipid distribution and microvillus integrity in Drosophila melanogaster

Lipids are either taken up from food sources or produced internally in specialized tissues such as the liver. Among others, both routes of lipid metabolism involve cytochrome P450 monooxygenases (CYPs). We sought to analyze the function of Cyp311a1 that has been shown to be expressed in the midgut of the fruit fly Drosophila melanogaster. Using a GFP-tagged version of CYP311A1 that is expressed under the control of its endogenous promoter, we show that Cyp311a1 localizes to the endoplasmic reticulum in epithelial cells of the anterior midgut. In larvae with reduced Cyp311a1 expression in the anterior midgut, compared to control larvae, the apical plasma membrane of the respective epithelial cells contains less and shorter microvilli. In addition, we observed reduction of neutral lipids in the fat body, the insect liver, and decreased phosphatidylethanolamine (PE) and triacylglycerols (TAG) amounts in the whole body of these larvae. Probably as a consequence, they cease to grow and eventually die. The microvillus defects in larvae with reduced Cyp311a1 expression are restored by supplying PE, a major phospholipid of plasma membranes, to the food. Moreover, the growth arrest phenotype of these larvae is partially rescued. Together, these results suggest that the anterior midgut is an import hub in lipid distribution and that the midgut-specific CYP311A1 contributes to this function by participating in shaping microvilli in a PE-dependent manner.

Linkage and association analyses reveal that hub genes in energy-flow and lipid biosynthesis pathways form a cluster in upland cotton

Upland cotton is an important allotetraploid crop that provides both natural fiber for the textile industry and edible vegetable oil for the food or feed industry. To better understand the genetic mechanism that regulates the biosynthesis of storage oil in cottonseed, we identified the genes harbored in the major quantitative trait loci/nucleotides (QTLs/QTNs) of kernel oil content (KOC) in cottonseed via both multiple linkage analyses and genome-wide association studies (GWAS). In ‘CCRI70′ RILs, six stable QTLs were simultaneously identified by linkage analysis of CHIP and SLAF-seq strategies. In ‘0-153′ RILs, eight stable QTLs were detected by consensus linkage analysis integrating multiple strategies. In the natural panel, thirteen and eight loci were associated across multiple environments with two algorithms of GWAS. Within the confidence interval of a major common QTL on chromosome 3, six genes were identified as participating in the interaction network highly correlated with cottonseed KOC. Further observations of gene differential expression showed that four of the genes, LtnD, PGK, LPLAT1, and PAH2, formed hub genes and two of them, FER and RAV1, formed the key genes in the interaction network. Sequence variations in the coding regions of LtnD, FER, PGK, LPLAT1, and PAH2 genes may support their regulatory effects on oil accumulation in mature cottonseed. Taken together, clustering of the hub genes in the lipid biosynthesis interaction network provides new insights to understanding the mechanism of fatty acid biosynthesis and TAG assembly and to further genetic improvement projects for the KOC in cottonseeds.

New understanding of Angelica sinensis polysaccharide improving fatty liver: The dual inhibition of lipid synthesis and CD36-mediated lipid uptake and the regulation of alcohol metabolism

Angelica sinensis polysaccharide (ASP) has presented increasingly recognized lipid regulation and antioxidant abilities. However, there is little direct evidence to explain why ASP possesses the observed lipid-lowering and anti-oxidation effects. In vivo and in vitro models of alcoholic fatty liver disease (AFLD) were established to examine the direct effect of ASP on hepatic fat accumulation. Our results showed that the lipid-lowering effect of ASP might result from the dual inhibition of lipid synthesis and CD36-mediated lipid uptake. The antioxidation of ASP might be attributed to the reversal of alcohol metabolic pathways from CYP2E1 catalysis to ADH catalysis. Taken together, the study demonstrated the direct role of ASP in lipid metabolism for the first time and revealed the underlying mechanism of reducing ROS, providing an available strategy for ASP as a potential agent to treat AFLD.

Mechanisms of intestinal triacylglycerol synthesis

Triacylglycerols are a major source of stored energy that are obtained either from the diet or can be synthesized to some extent by most tissues. Alterations in pathways of triacylglycerol metabolism can result in their excessive accumulation leading to obesity, insulin resistance, cardiovascular disease and nonalcoholic fatty liver disease. Most tissues in mammals synthesize triacylglycerols via the glycerol 3-phosphate pathway. However, in the small intestine the monoacylglycerol acyltransferase pathway is the predominant pathway for triacylglycerol biosynthesis where it participates in the absorption of dietary triacylglycerol. In this review, the enzymes that are part of both the glycerol 3-phosphate and monoacylglycerol acyltransferase pathways and their contributions to intestinal triacylglycerol metabolism are reviewed. The potential of some of the enzymes involved in triacylglycerol synthesis in the small intestine as possible therapeutic targets for treating metabolic disorders associated with elevated triacylglycerol is briefly discussed.

Genetic Alteration, Prognostic and Immunological Role of Acyl-CoA Synthetase Long-Chain Family Member 4 in a Pan-Cancer Analysis

Acyl-CoA Synthetase long-chain family member 4 (ACSL4) is a member of acyl-CoA synthetase protein long-chain family, which is associated with amino acid synthesis, lipid synthesis and lipid peroxidation dependent iron death. However, the role of ACSL4 in generalized carcinoma remains unclear. We aim to analyze the expression and prognostic value of ACSL4 in pan-cancer, and further explore the correlation between ACSL4 and immune infiltration. Through ONCOMINE, TIMER (Tumor Immune Estimation Resource), GEPIA (Gene expression Profiling Interactive), UALCAN and HPA, ACSL4 expression patterns of in pan-cancer were analyzed. The prognostic value of ACSL4 was analyzed using PrognoScan and Kaplan-Meier Plotter databases. Furthermore, gene variation and epigenetic modification of ACSL4 were analyzed by cBioPortal and GSCA databases. Meanwhile, GEPIA and TIMER databases applied to evaluate the relationship between ACSL4 expression and immune infiltration. These results indicate that ACSL4 expression is down-regulated and associated with prognosis in most tumors. In general, lower ACSL4 expression shows more beneficial prognosis. The most common genetic alteration of ACSL4 is point mutation. ACSL4 is negatively correlated with DNA methylation levels in most cancers. ACSL4 mutations or hypomethylation are associated with poor prognosis. In addition, ACSL4 is positively correlated with immune infiltration in cancers. ACSL4 and immune infiltration are strongly associated with prognosis in BRCA (Breast invasive carcinoma) and SKCM (Skin Cutaneous Melanoma). ACSL4 mutation caused significant changes of immune infiltration in UCEC (Uterine Corpus Endometrial Carcinoma) and SARC (Sarcoma). ACSL4 may be a promising prognostic biomarker for pan-cancer and is closely associated with immune infiltration in the tumor microenvironment.

Interference With ACSL1 Gene in Bovine Adipocytes: Transcriptome Profiling of mRNA and lncRNA Related to Unsaturated Fatty Acid Synthesis

The enzyme long-chain acyl-CoA synthetase 1 (ACSL1) is essential for lipid metabolism. The ACSL1 gene controls unsaturated fatty acid (UFA) synthesis as well as the formation of lipid droplets in bovine adipocytes. Here, we used RNA-Seq to determine lncRNA and mRNA that regulate UFA synthesis in bovine adipocytes using RNA interference and non-interference with ACSL1. The corresponding target genes of differentially expressed (DE) lncRNAs and the DE mRNAs were found to be enriched in lipid and FA metabolism-related pathways, according to GO and KEGG analyses. The differentially expressed lncRNA- differentially expressed mRNA (DEL-DEM) interaction network indicated that some DELs, such as TCONS_00069661, TCONS_00040771, TCONS_ 00035606, TCONS_00048301, TCONS_001309018, and TCONS_00122946, were critical for UFA synthesis. These findings assist our understanding of the regulation of UFA synthesis by lncRNAs and mRNAs in bovine adipocytes.

Update and nomenclature proposal for mammalian lysophospholipid acyltransferases which create membrane phospholipid diversity

The diversity of glycerophospholipid species in cellular membranes is immense and affects various biological functions. Glycerol-3-phosphate acyltransferases (GPATs) and lysophospholipid acyltransferases (LPLATs), in concert with phospholipase A_1/2s enzymes, contribute to this diversity via selective esterification of fatty acyl chains at the sn-1 or sn-2 positions of membrane phospholipids. These enzymes are conserved across all kingdoms, and in mammals four GPATs of the 1-acylglycerol-3-phosphate O-acyltransferase (AGPAT) family and at least 14 LPLATs, either of the AGPAT or the membrane-bound O-acyltransferase (MBOAT) families, have been identified. Here we provide an overview of the biochemical and biological activities of these mammalian enzymes, including their predicted structures, involvements in human diseases, and essential physiological roles as revealed by gene-deficient mice. Recently, the nomenclature used to refer to these enzymes has generated some confusion due to the use of multiple names to refer to the same enzyme and instances of the same name being used to refer to completely different enzymes. Thus, this review proposes a more uniform LPLAT enzyme nomenclature, as well as providing an update of recent advances made in the study of LPLATs, continuing from our JBC mini review in 2009.

Research progress of nanocarriers for gene therapy targeting abnormal glucose and lipid metabolism in tumors

In recent years, the incidence of various types of tumors has gradually increased, and it has also been found that there is a certain correlation between abnormal glucose and lipid metabolism and tumors. Glycolipid metabolism can promote tumor progression through multiple pathways, and the expression of related genes also directly or indirectly affects tumor metabolism, metastasis, invasion, and apoptosis. There has been much research on targeted drug delivery systems designed for abnormal glucose and lipid metabolism due to their accuracy and efficiency when used for tumor therapy. In addition, gene mutations have become an important factor in tumorigenesis. For this reason, gene therapy consisting of drugs designed for certain specifically expressed genes have been transfected into target cells to express or silence the corresponding proteins. Targeted gene drug vectors that achieve their corresponding therapeutic purposes are also rapidly developing. The genes related to glucose and lipid metabolism are considered as the target, and a corresponding gene drug carrier is constructed to influence and interfere with the expression of related genes, so as to block the tumorigenesis process and inhibit tumor growth. Designing drugs that target genes related to glucose and lipid metabolism within tumors is considered to be a promising strategy for the treatment of tumor diseases. This article summarizes the chemical drugs/gene drug delivery systems and the corresponding methods used in recent years for the treatment of abnormal glucose and lipid metabolism of tumors, and provides a theoretical basis for the development of glucolipid metabolism related therapeutic methods.

Interference with ACSL1 gene in bovine adipocytes: Transcriptome profiling of circRNA related to unsaturated fatty acid production

Long-chain acyl-CoA synthetase 1 (ACSL1) is a member of the acyl-CoA synthetase family that plays a vital role in lipid metabolism. We have previously shown that the ACSL1 gene regulates the composition of unsaturated fatty acids (UFAs) in bovine skeletal muscle, which in turn regulates the fatty acid synthesis and the generation of lipid droplets. Here, we used RNA-Seq to screen circRNAs that regulated the expression of ACSL1 gene and other UFA synthesis-related genes by RNA interference and noninterference in bovine adipocytes. The results of KEGG pathway analysis showed that the parental genes of differentially expressed (DE)-circRNAs were primarily enriched in the adipocytokine signaling pathway. The prediction results showed that novel_circ_0004855, novel_circ_0001507, novel_circ_0001731, novel_circ_0005276, novel_circ_0002060, novel_circ_0005405 and novel_circ_0004254 regulated UFA synthesis-related genes by interacting with the related miRNAs. These results could help expand our knowledge of the molecular mechanisms of circRNAs in the regulation of UFA synthesis in bovine adipocytes.

Single nucleotide polymorphism scanning and expression analysis of ACSL1 from different duck breeds

Accumulating studies have indicated that the long-chain fatty acyl-CoA1 (ACSL1) gene is related to fat deposition and meat quality in mammals. However, few studies have investigated the relationship between ACSL1 and lipid deposition in ducks. To examine this, we assessed the physicochemical property, homologous alignment, and phylogenetic analyses of the ACSL1 amino acid sequence using bioinformatics tools. The analysis indicated that the ACSL1 amino acid sequence varies in animals, and the duck ACSL1 protein is most closely related to that of chicken. Two single nucleotide polymorphism (SNP) sites were identified at 1749 and 1905 bp of the coding region of ACSL1 by sequencing. Quantitative real-time PCR and western blotting were used to measure mRNA and protein levels in abdominal fat, breast muscle, and liver tissue of Pekin duck (BD) and Cherry Valley duck (CD). mRNA and protein expression were significantly higher in BD than in CD in abdominal fat and liver tissue (P < 0.05). In breast muscle, the mRNA level of ACSL1 was also significantly higher in BD than in CD (P < 0.05), and protein expression in BD tended to be higher than that of CD. These results suggest that ACSL1 may contribute to lipid deposition and meat quality in ducks.

Identifying critical genes associated with aneurysmal subarachnoid hemorrhage by weighted gene co-expression network analysis

Aneurysmal subarachnoid hemorrhage (aSAH) is a life-threatening medical condition with a high mortality and disability rate. aSAH has an unclear pathogenesis, and limited treatment options are available. Here, we aimed to identify critical genes involved in aSAH pathogenesis using peripheral blood gene expression data of 43 patients with aSAH due to ruptured intracranial aneurysms and 18 controls with headache, downloaded from Gene Expression Omnibus. These data were used to construct a co-expression network using weighted gene co-expression network analysis (WGCNA). The biological functions of the hub genes were explored, and critical genes were selected by combining with differentially expressed genes analysis. Fourteen modules were identified by WGCNA. Among those modules, red, blue, brown and cyan modules were closely associated with aSAH. Moreover, 364 hub genes in the significant modules were found to play important roles in aSAH. Biological function analysis suggested that protein biosynthesis-related processes and inflammatory responses-related processes were involved in the pathology of aSAH pathology. Combined with differentially expressed genes analysis and validation in 35 clinical samples, seven gene (CD27, ANXA3, ACSL1, PGLYRP1, ALPL, ARG1, and TPST1) were identified as potential biomarkers for aSAH, and three genes (ANXA3, ALPL, and ARG1) were changed with disease development, that may provide new insights into potential molecular mechanisms for aSAH.

Association of the odd-chain fatty acid content in lipid groups with type 2 diabetes risk: A targeted analysis of lipidomics data in the EPIC-Potsdam cohort

BACKGROUND

Plasma odd-chain saturated fatty acids (OCFA) are inversely associated with type 2 diabetes (T2D) risk and may serve as biomarkers for dairy fat intake. Their distribution across different lipid classes and consequences for diabetes risk remain unknown.

AIM

To investigate the prospective associations of OCFA-containing lipid species with T2D risk and their dietary determinants.

METHODS

Within the European Prospective Investigation into Cancer and Nutrition-Potsdam study (n = 27,548), we applied a nested case-cohort design (subcohort: n = 1,248; T2D cases: n = 820; median follow-up 6.5 years). OCFA-containing lipids included triacylglycerols, free fatty acids (FFA), cholesteryl esters (CE), phosphatidylcholines, phosphatidylethanolamines, lysophosphatidylcholines, lysophosphatidylethanolamines, monoacylglycerols, and diacylglycerols. We estimated lipid class-specific associations between OCFA-containing lipids and T2D in sex-stratified Cox proportional-hazards models. We investigated correlations between lipids and dietary intakes derived from food-frequency questionnaires.

RESULTS

We observed heterogeneous integration of OCFA in different lipid classes: triacylglycerols, FFA, CE, and phosphatidylcholines contributed most to the total OCFA-plasma abundance. The relative concentration of OCFA was particularly high in monoacylglycerols, and the contribution of C15:0 versus C17:0 to the total OCFA-abundance differed across lipid classes. In women, several OCFA-containing phospholipids were inversely associated with T2D risk [phosphatidylcholine(C15:0), HR Q5 vs Q1: 0.56, 95% CI 0.32-0.97; phosphatidylcholine(C17:0), HR per SD: 0.59, 95% CI 0.48-0.71; lysophosphatidylcholine(C17:0), HR Q5 vs Q1: 0.42, 95% CI 0.23-0.76]. In men, we did not detect statistically significant inverse associations in phospholipids, and lysophosphatidylcholine(C15:0) was associated with higher T2D risk (HR Q5 vs. Q1: 1.96, 95% CI 1.06-3.63). Besides, CE(C17:0), monoacylglycerols(C15:0), and diacylglycerols(C15:0) were inversely associated with T2D risk; FFA(C17:0) was positively associated with T2D risk in women. Consumption of fat-rich dairy and fiber-rich foods were positively and red meat inversely correlated to OCFA-containing lipid plasma levels.

CONCLUSIONS

OCFA-containing lipids are linked to T2D risk in a lipid class and sex-specific manner, and they are correlated with several foods.

Metabolomic and Lipidomic Approaches to Evaluate the Effects of Eucommia ulmoides Leaves on Milk Quality and Biochemical Properties

Eucommia ulmoides leaves (EUL) contain a variety of natural bioactive compounds including chlorogenic acid, geniposide acid, and aucubin. These bioactive chemicals improve immune function and regulate lipid metabolism. The aim of this study was to investigate the effects of EUL on the biochemical properties of milk. Twenty Holstein dairy cows were randomly allocated to two groups fed a control (CTR, diet without EUL, n = 10) or EUL (diet containing 3% EUL, dry matter, n = 10) diet for 55 d. At the end of the experimental period (d 55), milk samples were collected and analyzed to determine their composition. Though levels of milk fat, protein, lactose, and total milk solids were similar between the groups, small molecules, metabolites, lipids, and cytokines differed. Compared with the CTR group, the EUL group had an improved cluster of differentiation (CD)4/CD8 ratio (P < 0.05) and lower interleukin (IL)-8 and IL-6 content (P < 0.05). Metabolomics analysis identified 14 metabolites including 7Z, 10Z, 13Z, 16Z, 19Z-docosapentaenoic acid (FC = 3.129), adrenic acid (FC = 2.830), and eicosapentaenoic acid (FC=1.685) as having significantly increased in the EUL group (P < 0.05) while 11 metabolites, including indole-2-carboxylic acid (FC = 0.636), cholic acid (FC = 0.430), and creatine (FC = 0.784) had significantly decreased (P < 0.05). Based on a constructed metabolome map, linoleic acid metabolism had the highest impact value for EUL. A total of 21 lipid classes and 1,094 lipid species were detected in the milk by lipidomic analysis, among which 40 differed significantly between the CTR and EUL groups. The present findings showed that the EUL altered milk composition. Correlation analysis showed that 7Z, 10Z, 13Z, 16Z, 19Z-docosapentaenoic acid, adrenic acid, and eicosapentaenoic acid levels were negatively correlated with those of the inflammatory factors IL-6 and IL-8 (P < 0.05), indicating that EUL improved milk quality by reducing inflammatory factors and increasing the CD4/CD8 ratio. Overall, our data demonstrate that EUL had positive effects on milk antioxidant parameters, immune indices, and micro-composition metabolism, thereby improving milk quality.

Metformin relieves H/R-induced cardiomyocyte injury through miR-19a/ACSL axis - possible therapeutic target for myocardial I/R injury

This study proposed to investigate the function of miR-19a/ACSL axis in hypoxia/reoxygenation (H/R)-induced myocardial injury and determine whether metformin exerts its protective effect via miR-19a/ACSL axis. Firstly, bioinformatics analysis of data from Gene Expression Omnibus (GEO) database indicated that miR-19a was downregulated in patients with myocardial infarction (MI) compared to that in control group. H/R model was constructed with AC16 cells in vitro. qRT-PCR assay revealed that miR-19a was downregulated in H/R-treated AC16 cells. Then, CCK-8 assay demonstrated that upregulation of miR-19a significantly alleviated H/R-induced decline of cell viability. Moreover, bioinformatics prediction, western blotting and dual-luciferase reporter assays were performed to check the target genes of miR-19a, and ACSL1 was determined as a downstream target gene of miR-19a. Besides, the analysis based on Comparative Toxicogenomics Database (CTD) suggested that metformin targeting ACSL1 can be used as a potential drug for further research. Biological function experiments in vitro revealed that H/R markedly declined the viability and elevated the apoptosis of AC16 cells, while metformin can significantly mitigate these effects. Furthermore, overexpression of miR-19a significantly strengthened the beneficial effect of metformin on H/R-induced AC16 cells injury, which can be reversed by upregulation of ACSL1. In conclusion, metformin can alleviate H/R-induced cells injury via regulating miR-19a/ACSL axis, which lays a foundation for identifying novel targets for myocardial I/R injury therapy.

Lipodistrophy: a paradigm for understanding the consequences of "overloading" adipose tissue

Lipodystrophies have been recognized since at least the nineteenth century and, despite their rarity, tended to attract considerable medical attention because of the severity and somewhat paradoxical nature of the associated metabolic disease that so closely mimics that of obesity. Within the last 20 yr most of the monogenic subtypes have been characterized, facilitating family genetic screening and earlier disease detection as well as providing important insights into adipocyte biology and the systemic consequences of impaired adipocyte function. Even more recently, compelling genetic studies have suggested that subtle partial lipodystrophy is likely to be a major factor in prevalent insulin-resistant type 2 diabetes mellitus (T2DM), justifying the longstanding interest in these disorders. This progress has also underpinned novel approaches to treatment that, in at least some patients, can be of considerable therapeutic benefit.

TANK-Binding Kinase 1 Regulates the Localization of Acyl-CoA Synthetase ACSL1 to Control Hepatic Fatty Acid Oxidation

Hepatic TANK (TRAF family member associated NFκB activator)-binding kinase 1 (TBK1) activity is increased during obesity, and administration of a TBK1 inhibitor reduces fatty liver. Surprisingly, liver-specific TBK1 knockout in mice produces fatty liver by reducing fatty acid oxidation. TBK1 functions as a scaffolding protein to localize acyl-CoA synthetase long-chain family member 1 (ACSL1) to mitochondria, which generates acyl-CoAs that are channeled for β-oxidation. TBK1 is induced during fasting and maintained in the unphosphorylated, inactive state, enabling its high affinity binding to ACSL1 in mitochondria. In TBK1-deficient liver, ACSL1 is shifted to the endoplasmic reticulum to promote fatty acid re-esterification in lieu of oxidation in response to fasting, which accelerates hepatic lipid accumulation. The impaired fatty acid oxidation in TBK1-deficient hepatocytes is rescued by the expression of kinase-dead TBK1. Thus, TBK1 operates as a rheostat to direct the fate of fatty acids in hepatocytes, supporting oxidation when inactive during fasting and promoting re-esterification when activated during obesity.

Effects of overexpression of ACSL1 gene on the synthesis of unsaturated fatty acids in adipocytes of bovine

There exists a positive correlation between the unsaturated fatty acids (UFA) content in the bovine species and their taste and nutritional significance. Long-chain acyl-CoA synthetase 1 (ACSL1) is known to be involved in lipid synthesis as well as fatty acid transport and degradation. This gene has been identified as the key candidate gene for regulating lipid composition in the bovine skeletal muscle; however, its mechanism of action in regulating UFA synthesis in bovine adipocytes is unclear. In this study, we used a recombinant adenovirus vector (Ad-ACSL1) to overexpress the ACSL1 gene using Ad-NC (recombinant adenovirus of green fluorescent protein) as the control. Quantitative real-time PCR (qRT-PCR) was done to examine the gene expression associated with the synthesis of UFA, followed by the analysis of the fatty acid composition. Oil red O staining was done to examine the aggregation of lipid droplets. We found that ACSL1 overexpression was associated with an upregulated expression of PPARγ, FABP3, ACLY, SCD1, and FASN, and downregulated expression of CPT1A. Additionally, ACSL1 overexpression resulted in elevated saturated fatty acid content, especially C16:0 and C18:0, than the control group (Ad-NC cells) (p < 0.05). Furthermore, the overexpression of ACSL1 enhanced the proportion of eicosapentaenoic acid (EPA), decreased the proportion of C22:4, and significantly upregulated polyunsaturated fatty acid (PUFA) content. These results were supported by oil red O staining, which revealed an increase in the lipid droplets in bovine adipocytes after the overexpression of the ACSL1 gene. Thus, the results of this study indicated that ACSL1 positively regulated PUFA synthesis in bovine adipocytes.

Expression profiles and polymorphic identification of the ACSL1 gene and their association with body size traits in Dezhou donkeys

Finding out the genetic mechanism of growth and development traits and the development of related molecular markers can help improve the breeding of livestock. The long-chain acyl coenzyme A synthase 1 (ACSL1) gene plays a major role in lipid synthesis and fatty acid catabolism. However, there are few studies on the ACSL1 gene polymorphism of Dezhou donkeys. This study analyzed the expression level of the ACSL1 gene in different tissues of young and adult Dezhou donkeys, as well as association analysis of four gene polymorphic loci in 450 individuals. The results showed that expression levels of the ACSL1 gene are higher in heart, liver, spleen, lung, renal, gastric and muscle tissues of adult donkeys than in those of young donkeys. In the association analysis between genotype and body size traits, the wild genotype DD at the ACSL1-1 locus in female and male donkeys was greater than the mutant genotype II (P<0.05); genotype II of ACSL1-2 was significantly higher than that of DD in withers height, body length, rump width and body weight of male donkeys (P<0.05); and ACSL1-3 showed a tendency for the wild genotype II to be greater than the mutant genotype DD in female and male donkeys (P<0.05). In addition, among the five haplotype combinations constructed, Hap3Hap3 (II-II-DD-DD) and Hap6Hap6 (DD-II-II-II) haplotype combinations were superior to other haplotype combinations in growth traits, which also indicated that the results of haplotype combination association analysis and genotype association analysis tended to be the same. In conclusion, the results of this study indicate that the polymorphic loci of the ACSL1 gene can be used as candidate molecular markers for the growth and development of Dezhou donkeys, and provide a theoretical reference for the breeding of Dezhou donkeys.

Diet and Exercise Training Influence Skeletal Muscle Long-Chain acyl-CoA Synthetases

INTRODUCTION

Long-chain acyl-CoA synthetases (ACSL) are implicated as regulators of oxidation and storage of fatty acids within skeletal muscle; however, to what extent diet and exercise alter skeletal muscle ACSL remains poorly understood.

PURPOSE

This study aimed to determine the effects of diet and exercise training on skeletal muscle ACSL and to examine relationships between ACSL1 and ACSL6 and fat oxidation and fat storage, respectively.

METHODS

Male C57BL/6J mice consumed a 60% high-fat diet (HFD) for 12 wk to induce obesity compared with low-fat diet (LFD). At week 4, mice began aerobic exercise (EX-Tr) or remained sedentary (SED) for 8 wk. At week 12, the protein abundance of five known ACSL isoforms and mRNA expression for ACSL1 and ACSL6 were measured in gastrocnemius muscle, as was skeletal muscle lipid content. Fat oxidation was measured using metabolic cage indirect calorimetry at week 10.

RESULTS

Of the five known ACSL isoforms, four were detected at the protein level. HFD resulted in greater, yet nonsignificant, ACSL1 protein abundance (+18%, P = 0.13 vs LFD), greater ACSL6 (+107%, P < 0.01 vs LFD), and no difference in ACSL4 or ACSL5. Exercise training resulted in greater ACSL6 protein abundance in LFD mice (P = 0.05 LFD EX-Tr vs SED), whereas ACSL4 was lower after exercise training compared with sedentary, regardless of diet. Under fasted conditions, skeletal muscle ACSL1 protein abundance was not related to measures of whole-body fat oxidation. Conversely, skeletal muscle ACSL6 protein abundance was positively correlated with intramyocellular lipid content (P < 0.01, r = 0.22).

CONCLUSION

We present evidence that ACSL isoforms 1, 4, and 6 may undergo regulation by HFD and/or exercise training. We further conclude that increased skeletal muscle ACSL6 may facilitate increased intramyocellular fat storage during HFD-induced obesity.

Muscle-Specific Lipid Hydrolysis Prolongs Lifespan through Global Lipidomic Remodeling

A growing body of evidence suggests that changes in fat metabolism may have a significant effect on lifespan. Accumulation of lipid deposits in non-adipose tissue appears to be critical for age-related pathologies and may also contribute to the aging process itself. We established a model of lipid storage in muscle cells of C. elegans to reveal a mechanism that promotes longevity non-cell-autonomously. Here, we describe how muscle-specific activation of adipose triglyceride lipase (ATGL) and the phospholipase A₂ (PLA₂) ortholog IPLA-7 collectively affect inter-tissular communication and systemic adaptation that requires the activity of AMP-dependent protein kinase (AMPK) and a highly conserved nuclear receptor outside of the muscle. Our data suggest that muscle-specific bioactive lipid signals, or "lipokines," are generated following triglyceride breakdown and that these signals impinge on a complex network of genes that modify the global lipidome, consequently extending the lifespan.

Protective Mechanism of Common Buckwheat (Fagopyrum esculentum Moench.) against Nonalcoholic Fatty Liver Disease Associated with Dyslipidemia in Mice Fed a High-Fat and High-Cholesterol Diet

This study aimed to investigate the protective mechanism of common buckwheat (Fagopyrum esculentum Moench.) against nonalcoholic fatty liver disease (NAFLD) associated with dyslipidemia in mice that were fed a high-fat and high-cholesterol diet (HFD). Results showed that oral supplementation of common buckwheat significantly improved physiological indexes and biochemical parameters related to dyslipidemia and NAFLD in mice fed with HFD. Furthermore, the HFD-induced reductions in fecal short-chain fatty acids were reversed by common buckwheat intervention, which also increased the fecal bile acid (BA) abundance compared with HFD-induced hyperlipidemic mice. Liver metabolomics based on ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry demonstrated that common buckwheat supplementation made significant regulatory effects on the pentose phosphate pathway, starch and sucrose metabolism, primary BA biosynthesis, and so forth. The results of high-throughput sequencing revealed that common buckwheat supplementation significantly altered the structure of the intestinal microbiota in mice fed with HFD. The correlations between lipid metabolic parameters and intestinal microbial phylotypes were also revealed by the heatmap and network. Additionally, common buckwheat intervention regulated the mRNA expressions of genes responsible for liver lipid metabolism and BA homeostasis, thus promoting BA synthesis and excretion. These findings confirmed that common buckwheat has the outstanding ability of improving lipid metabolism and could be used as a potential functional food for the prevention of NAFLD and hyperlipidemia.

Metabolomic, functional, and ecologic responses of the common freshwater fungus Neonectria lugdunensis to mine drainage stress

Metal contamination of watersheds is a global problem. Here, we conducted litter decomposition studies with Neonectria lugdunensis, a cosmopolitan aquatic fungus. Fungal isolates from four reference (non-impacted) and six metal-contaminated streams (due to mine drainage) were exposed to mine drainage and reference stream waters in Central Portugal. Impact of mine drainage waters on N. lugdunensis hyphae was investigated by performing metabolomic profiling of 200 lipids and 25 amino acids (AA) with ultra-high performance liquid chromatography-mass spectrometry. In parallel, functional response of N. lugdunensis isolates was assessed through expression profiles of a functional gene, cellobiohydrolase I (CbhI). Ecological performance via leaf mass loss was also determined. Exposure to mine drainage waters altered the concentration of numerous AA and lipids. Most strikingly, a gradual increase in the concentration of the triacylglycerols (TAG) with shorter acyl chains and lesser unsaturation was observed after the exposure to mine drainage waters. In addition, the changes in the concentration of numerous TAG, lysophosphatidylcholines, and AA were more significant in the isolates from the metal-contaminated streams after exposure to mine drainage water. CbhI gene of the isolates from reference streams was down-regulated by metal stress, while those from metal-contaminated streams remained unaffected. Finally, leaf mass loss was influenced by both exposure to mine drainage waters and the origin of isolates. Overall, our study demonstrates unique functional signatures displayed by fungi under metal stress and the relevant role that fungal AA and lipids play to cope with metal toxicity.

ACSL1 affects Triglyceride Levels through the PPARγ Pathway

In clinical cohort studies, high expression of long-chain acyl-coenzyme A synthetases 1 (ACSL1 gene) in peripheral white blood cells of patients with acute myocardial infarction (AMI) has been utilized as molecular markers of myocardial infarction diagnosis. The plasma triglyceride level of AMI patients is significantly higher than that of healthy individuals. We hypothesized that the high expression of ACSL1 increases the level of triglyceride, which is one of the pathogenesis of AMI promoted by ACSL1. In this report, cell culture based methods were adopted to test the hypothesis and further investigate the effect and mechanism of ACSL1 on lipid metabolism. In this study, liver cells of healthy individuals were cultured, the overexpression and the knockdown vectors of ACSL1 were constructed and transfected into liver cells. The transfection was verified at the mRNA and protein level. Intracellular triglyceride content was quantitatively analyzed using ELISA. Changes of genes related to lipid metabolism were subsequently measured through PCR array. Overexpression of ACSL1 led to higher gene expression and protein levels compared to control and the triglyceride content was significantly increased in overexpressing cells. The expression level of fatty acid oxidation pathway PPARγ was significantly down-regulated compared with the control group, as were genes associated with fatty acid synthesis pathways: SREBP1, ACC, FAS, and SCD1. ACSL1 knockdown decreased the content of triglyceride whereas PPARγ was up-regulated and SREBP1, ACC, FAS, and SCD1 were down-regulated compared with the control group. In summary, high expression of ACSL1 reduced fatty acid β-oxidation through the PPARγ pathway, thereby increasing triglyceride levels.