Glycerol Kinase Drives Hepatic de novo Lipogenesis and Triglyceride Synthesis in Nonalcoholic Fatty Liver by Activating SREBP-1c Transcription, Upregulating DGAT1/2 Expression, and Promoting Glycerol Metabolism.

Glycerol kinase (GK) participates in triglyceride (TG) synthesis by catalyzing glycerol metabolism. Whether GK contributes to nonalcoholic fatty liver (NAFL) is unclear. The expression of hepatic Gk is found to be increased in diet-induced and genetic mouse models of NAFL and is positively associated with hepatic SREBP-1c expression and TG levels. Cholesterol and fatty acids stimulate GK expression in hepatocytes. In HFD-induced NAFL mice, knockdown of hepatic Gk decreases expression of SREBP-1c and its target lipogenic genes as well as DGAT1/2, increases serum glycerol levels, decreases serum TG levels, and attenuates hepatic TG accumulation. Overexpression of GK in hepatocytes in mice or in culture produces opposite results. Mechanistic studies reveal that GK stimulates SREBP-1c transcription directly by binding to its gene promoter and indirectly by binding to SREBP-1c protein, thereby increasing lipogenic gene expression and de novo lipogenesis. Studies with truncated GK and mutant GKs indicate that GK induces SREBP-1c transcription independently of its enzyme activity. GK contributes to lipid homeostasis under physiological conditions by catalyzing glycerol metabolism rather than by regulating SREBP-1c transcription. Collectively, these results demonstrate that increased hepatic GK promotes de novo lipogenesis and TG synthesis in NAFL by stimulating SREBP-1c transcription and DGAT1/2 expression and catalyzing glycerol metabolism.

The Downregulation of the Liver Lipid Metabolism Induced by Hypothyroidism in Male Mice: Metabolic Flexibility Favors Compensatory Mechanisms in White Adipose Tissue.

In mammals, the maintenance of energy homeostasis relies on complex mechanisms requiring tight synchronization between peripheral organs and the brain. Thyroid hormones (THs), through their pleiotropic actions, play a central role in these regulations. Hypothyroidism, which is characterized by low circulating TH levels, slows down the metabolism, which leads to a reduction in energy expenditure as well as in lipid and glucose metabolism. The objective of this study was to evaluate whether the metabolic deregulations induced by hypothyroidism could be avoided through regulatory mechanisms involved in metabolic flexibility. To this end, the response to induced hypothyroidism was compared in males from two mouse strains, the wild-derived WSB/EiJ mouse strain characterized by a diet-induced obesity (DIO) resistance due to its high metabolic flexibility phenotype and C57BL/6J mice, which are prone to DIO. The results show that propylthiouracil (PTU)-induced hypothyroidism led to metabolic deregulations, particularly a reduction in hepatic lipid synthesis in both strains. Furthermore, in contrast to the C57BL/6J mice, the WSB/EiJ mice were resistant to the metabolic dysregulations induced by hypothyroidism, mainly through enhanced lipid metabolism in their adipose tissue. Indeed, WSB/EiJ mice compensated for the decrease in hepatic lipid synthesis by mobilizing lipid reserves from white adipose tissue. Gene expression analysis revealed that hypothyroidism stimulated the hypothalamic orexigenic circuit in both strains, but there was unchanged melanocortin 4 receptor (Mc4r) and leptin receptor (LepR) expression in the hypothyroid WSB/EiJ mice strain, which reflects their adaptability to maintain their body weight, in contrast to C57BL/6J mice. Thus, this study showed that WSB/EiJ male mice displayed a resistance to the metabolic dysregulations induced by hypothyroidism through compensatory mechanisms. This highlights the importance of metabolic flexibility in the ability to adapt to disturbed circulating TH levels.

Salidroside sensitizes Triple-negative breast cancer to ferroptosis by SCD1-mediated lipogenesis and NCOA4-mediated ferritinophagy.

INTRODUCTION: Triple-negative breast cancer (TNBC) is the primary cause of breast cancer-induced death in women. Literature has confirmed the benefits of Salidroside (Sal) in treating TNBC. However, the study about potential therapeutic targets and mechanisms of Sal-anchored TNBC remains limited. OBJECTIVE: This study was designed to explore the main targets and potential mechanisms of Sal against TNBC. METHODS: Network pharmacology, bioinformatics, and machine learning algorithm strategies were integrated to examine the role, potential targets, and mechanisms of the Sal act in TNBC. MDA-MB-231 cells and tumor-bearing nude mice were chosen for in vitro and in vivo experimentation. Cell viability and cytotoxicity were determined using CCK-8, LDH test, and Calcein-AM/PI staining. Antioxidant defense, lipid peroxidation, and iron metabolism were explored using glutathione, glutathione peroxidase, malondialdehyde (MDA), C11-BODIPY 581/591 probe, and FerroOrange dye. Glutathione peroxidase 4 (GPX4) or stearoyl-CoA desaturase 1 (SCD1) overexpression or nuclear receptor co-activator 4 (NCOA4) deficiency was performed to demonstrate the mechanism of Sal on TNBC. RESULTS: The prediction results confirmed that 22 ferroptosis-related genes were identified in Sal and TNBC, revealing that the potential mechanism of the Sal act on TNBC was linked with ferroptosis. Besides, these genes were mainly involved in the mTOR, PI3K/AKT, and autophagy signaling pathway by functional enrichment analysis. The in vitro validation results confirmed that Sal inhibited TNBC cell proliferation by modulating ferroptosis via elevation of intracellular Fe2+ and lipid peroxidation. Mechanistically, Sal sensitized TNBC cells to ferroptosis by inhibiting the PI3K/AKT/mTOR axis, thereby suppressing SCD1-mediated lipogenesis of monounsaturated fatty acids to induce lipid peroxidation, additionally facilitating NCOA4-mediated ferritinophagy to increase intracellular Fe2+ content. The GPX4 or SCD1 overexpression or NCOA4 deficiency results further supported our mechanistic studies. In vivo experimentation confirmed that Sal is vital for slowing down tumor growth by inducing ferroptosis. CONCLUSIONS: Overall, this study elucidates TNBC pathogenesis closely linked to ferroptosis and identifies potential biomarkers in TNBC. Meanwhile, the study elucidates that Sal sensitizes TNBC to ferroptosis by SCD1-mediated lipogenesis and NCOA4-mediated ferritinophagy, regulated by PI3K/AKT/mTOR signaling pathways. Our findings provide a theoretical basis for applying Sal to treat TNBC.

Amino acid is a major carbon source for hepatic lipogenesis.

Increased de novo lipogenesis is a hallmark of metabolic dysfunction-associated steatotic liver disease (MASLD) in obesity, but the macronutrient carbon source for over half of hepatic fatty acid synthesis remains undetermined. Here, we discover that dietary protein, rather than carbohydrates or fat, is the primary nutritional risk factor for MASLD in humans. Consistently, ex vivo tracing studies identify amino acids as a major carbon supplier for the tricarboxylic acid (TCA) cycle and lipogenesis in isolated mouse hepatocytes. In vivo, dietary amino acids are twice as efficient as glucose in fueling hepatic fatty acid synthesis. The onset of obesity further drives amino acids into fatty acid synthesis through reductive carboxylation, while genetic and chemical interventions that divert amino acid carbon away from lipogenesis alleviate hepatic steatosis. Finally, low-protein diets (LPDs) not only prevent body weight gain in obese mice but also reduce hepatic lipid accumulation and liver damage. Together, this study uncovers the significant role of amino acids in hepatic lipogenesis and suggests a previously unappreciated nutritional intervention target for MASLD.

Lipidomics reveals the lipid-lowering and hepatoprotective effects of Celosia Semen on high-fat diet-induced NAFLD mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Celosia Semen (CS) serves as a traditional Chinese medicine (TCM) for promoting liver health and enhancing vision, with extensive clinical applications. Triterpenoid saponins represent the primary active components of CS, with the highest concentration of Celosin I (CI) detected. The urgent need for effective NAFLD treatments motivated us assess the beneficial effects of total saponins from CS (TSCS) and CI. AIMS OF THE STUDY: To investigate the therapeutic effects of TSCS and CI on NAFLD and its underlying molecular mechanisms. MATERIALS AND METHODS: The impact of TSCS and CI on NAFLD was evaluated through in vitro and in vivo methodologies, utilizing high-fat diet (HFD) and palmitic acid/oleic acid modeling on C57BL/6J mice and AML12 cells, respectively. Biochemical analysis, H&E and Oil red O staining were used to characterize the lipid-lowering and hepatoprotective activities of TSCS and CI. Lipidomics discerned the impact of TSCS and CI interventions on liver lipid composition, distribution and alteration in NFALD mice. RT-qPCR and western blotting detected the influence of TSCS and CI on genes linked to de novo lipogenesis, fat calculation uptake, oxidation and esterification. The docking analysis anticipated the interaction of six major triterpenoid saponins within TSCS with SREBP1. RESULTS: TSCS and CI markedly diminished lipid accumulation induced by high fat both in vivo and in vitro. TSCS and CI also mitigated hepatic steatosis and liver injury induced by HFD through the reduction of TC, TG, FAs, ALT, and AST, even at minimal dose of 25 mg/kg. Lipidomics indicated that TSCS and CI had the potential to modulate the lipid metabolism network, rectify lipid metabolic dysregulation induced by NAFLD, decrease the levels of harmful lipids, and elevate the levels of advantageous lipids. Furthermore, TSCS and CI exhibited a strong affinity to SREBP1, thereby might directly influence the expression of SREBP1 and a cascade of essential enzymes involved in de novo lipogenesis, and finally resulting in a diminished synthesis of novel lipids. CONCLUSION: TSCS and CI were confirmed firstly as key active components of CS in amending hepatic steatosis and mitigate liver damage in NAFLD, outlining the preliminary mechanism. They warrant further exploration as drug candidates for NAFLD treatment, especially in light of the current shortage of medications and limited therapeutic options.

Lygodium microphyllum Inhibits de Novo Lipogenesis Activity in the Hepatocytes of High-Fat High-Fructose-Induced Rats by Increasing the Levels of SIRT1 and AMPK.

Background: The prevalence of non-alcoholic fatty liver disease (NAFLD) is currently of great concern due to its risk of developing T2DM and cardiovascular disease. The development of NAFLD may be initiated by de novo lipogenesis in the hepatocytes. Sirtuin1 (SIRT1) and adenosine monophosphate-activated protein kinase (AMPK), are responsible for the lipogenesis mechanism. Interestingly, plant sterols, such as beta-sitosterol and stigmasterol, have the potential to lower the LDL-cholesterol in dyslipidemic patients. Beta-sitosterol was present in the ethanol extract of Lygodium microphyllum herbs at a concentration of 283.55 µg/g extract. This sterol interacted with the active allosteric-binding site of SIRT1 and AMPK similarly to the proteins' activators. Purpose: To investigate the anti-lipogenesis activity of the ethanol extract of L. microphyllum (ELM) in the liver tissue of rats through the SIRT1 and AMPK levels. Methods: Forty male Wistar rats were used in this study: (1) normal control group; (2) high-fat high-fructose diet (HFHFD) rats; (3) HFHFD rats treated with metformin; (4) HFHFD rats treated with resveratrol; (5) HFHFD rats treated with beta-sitosterol; (6-8) HFHFD rats treated with ELM doses of 200, 400, and 600 mg/kg BW. Rats in the normal control group were fed regular chow, while other groups of rats were given HFHFD for 35 days. All drugs were given orally on D15 till D35. On D35, the rats were sacrificed, and the liver organs were examined for the liver index, morphology, NAFLD activity score (NAS), and levels of SIRT1 and AMPK. Results: ELM improves the morphology, the liver index, the steatosis condition, and the NAS of HFHFD-induced NAFLD rats. ELM increases the levels of SIRT1 and AMPK in the liver tissue of HFHFD-induced NAFLD rats. Conclusion: ELM may have the potential to inhibit de novo lipogenesis by increasing the levels of SIRT1 and AMPK.

Targeting acetyl-CoA carboxylases for the treatment of MASLD.

Hepatic accumulation of triglycerides is a hallmark feature of metabolic dysfunction-associated steatotic liver disease (MASLD). Growing evidence indicates that increased rates of de novo lipogenesis (DNL) is one of the earliest metabolic changes promoting hepatic steatosis in the onset of MASLD. The first step in DNL is catalyzed by acetyl-CoA carboxylases (ACC), which mediate the conversion of acetyl-CoA into malonyl-CoA. Given the critical role of ACC enzymes on DNL, ACC-based therapies have emerged as an attractive approach to address MASLD, leading to the development of pharmacologic inhibitors of ACC. In clinical trials, several of those compounds led to improved DNL rates and hepatic steatosis in MASLD patients. In this review, we describe the development of ACC dual inhibitors and isoform-specific inhibitors along with their clinical testing using monotherapy and combination therapy approaches. We also discuss their efficacy and safety profiles, identifying potential directions for future research. It is anticipated that advances in ACC-based therapies will be critical to the management of MASLD.

Semaglutide Treatment Effects on Liver Fat Content in Obese Subjects with Metabolic-Associated Steatotic Liver Disease (MASLD).

Background: Metabolic-dysfunction-associated steatotic liver disease (MASLD) represents a major clinical complication of obesity. Methods: In this study, we used magnetic resonance (MR) methods to determine the effect of obesity treatment with semaglutide, a GLP-1 receptor agonist, on the liver fat content and selected metabolic variables. We investigated whether treatment would affect the acute response of liver fat to glucose and fructose administration and whether it would affect the fatty acid profile of VLDL-triglycerides. Sixteen obese non-diabetic men underwent a 16-week dietary intervention and 16-week treatment with subcutaneous semaglutide in a crossover design without a washout period. The order of the interventions was randomized. Results: After treatment, body weight of the subjects decreased by 5% and liver fat by a third, whereas dietary intervention had no impact on these parameters. The decrease in liver fat with semaglutide did not correlate with changes in body weight and other measures of adiposity and was unrelated to improved insulin sensitivity. Conclusions: The proportion of palmitic and palmitoleic acids in VLDL-triglycerides decreased after treatment, suggesting that the beneficial effects of semaglutide on liver fat are mediated by the suppression of de novo lipogenesis.

The Protein/Carbohydrate Ratio in the Diet Affects Zootechnical Performance and the Regulation of Intermediary Metabolism in Juveniles Tambaqui (Colossoma macropomum).

The use of carbohydrates in animal feed is a way to save protein in the diet. This study evaluated the effect of protein/starch ratio on the performance, hepatic metabolism, and body composition of juvenile tambaqui (Colossoma macropomum). Six isoenergetic experimental diets were formulated containing three levels of digestible protein (P: 230, 260 and 290 g kg- 1) and two levels of starch (S: 180 and 280 g kg- 1): P23S18, P23S28, P26S18, P26S28, P29S18 and P29S28. Juveniles tambaqui (N = 288; initial weight = 30.0 ± 3.8 g) were fed experimental diets for 90 days and the zootechnical performance was evaluated. Nine fish from each treatment group were sampled to determine somatic indices, blood metabolites, tissue energy reserves, body composition and activity of key hepatic enzymes. Blood triglycerides, hepatosomatic index, liver and muscle lipids, and hepatic glycogen increased significantly with starch while blood glucose, triglycerides and cholesterol, muscle lipids were significantly impacted by protein levels. Fish-fed S28 had increased feed intake (1714-1829 g; p < 0.0001) and fish-fed diet P26S18 had a higher protein efficiency rate (23.62%; p = 0.0356). Fish fed P23 had lower crude protein retention in the carcass (p = 0.0018) and high lipogenesis and lipid deposition in the muscle (p = 0.0069). These results suggest that dietary carbohydrates have a protein-sparing effect. Tambaqui adapted well to diets containing starch, even at higher levels, resulting in an overall increase in lipogenesis from S18 to S28. Thus, we recommend P26S18 as a cost-effective feed that ensures both zootechnical performance and quality of the final product.

Two Triterpenoids, ARM-2 and RA-5, From Protorhus longifolia Exhibit the Potential to Modulate Lipolysis and Lipogenesis in Cultured 3T3-L1 Adipocytes.

Triterpenoids have been identified as potential novel lipid-lowering drugs for the treatment of hypertriglyceridemia. This study investigated the potential antilipogenic and/or antilipolytic effects of two triterpenoids (ARM-2 and RA-5) isolated from the stem bark of Protorhus longifolia (Benrh.) Engl. Employing a combination of in silico predictions and in vitro assays, the interactions between these triterpenoids and key proteins involved in lipogenesis and lipolysis were investigated. In silico molecular docking analysis predicted a favourable binding affinity of both triterpenoids to PPARγ, SREBP-1, and AMPK, with lower binding affinity to C/EBPα, pancreatic lipase, and hormone-sensitive lipase (HSL). Both triterpenoids exhibited in vitro inhibition of pancreatic lipase with Ki and IC50 values ranging from 28.7 to 52.9 µM and 27.6 to 35.8 µM, respectively. Total and neutral lipid accumulation in differentiated 3T3-L1 adipocytes and the oleic acid-induced HepG2 cell model was inhibited, with ARM-2 showing better inhibition than RA-5. In the HepG2 model, the inhibitory activity of the two triterpenoids (at 25 and 100 µM) was comparable to 50 µM lovastatin, although the latter was cytotoxic, whereas both ARM-2 and RA-2 lacked cytotoxicity. Associated gene expression was similar to the effect of simvastatin where the expression of SREBP-1, PPARγ, C/EBPα, and HSL was reduced and that of AMPK was unchanged. In vitro studies confirmed that ARM-2 and RA-5 also inhibited adipocyte lipolysis, where the reduction in glycerol release by 25 and 100 µM was similar to 50 µM lovastatin and simvastatin. This study identifies that the triterpenoids, ARM-2 and RA-5, have the potential to modulate lipogenesis and lipolysis.

Dissociation between liver fat content and fasting metabolic markers of selective hepatic insulin resistance in humans.

OBJECTIVE: Fasting hyperglycemia and hypertriglyceridemia are characteristic of insulin resistance (IR) and rodent work has suggested this may be due to selective hepatic IR, defined by increased hepatic gluconeogenesis and de novo lipogenesis (DNL), but this has not been shown in humans. DESIGN: Cross-sectional study in men and women across a range of adiposity. METHODS: Medication-free participants (n = 177) were classified as normoinsulinemic (NI) or hyperinsulinemic (HI) and as having low (LF) or high (HF) liver fat content measured by magnetic resonance spectroscopy. Fractional gluconeogenesis (frGNG) and hepatic DNL were measured using stable isotope tracer methodology following an overnight fast. RESULTS: Although HI and HF groups had higher fasting plasma glucose and triglyceride concentrations when compared to NI and LF groups respectively, there was no difference in frGNG. However, HF participants tended to have lower frGNG than LF participants. HI participants had higher DNL compared to NI participants but there was no difference observed between liver fat groups. CONCLUSIONS: Taken together, we found no metabolic signature of selective hepatic IR in fasting humans. DNL may contribute to hypertriglyceridemia in individuals with HI but not those with HF. Glycogenolysis and systemic glucose clearance may have a larger contribution to fasting hyperglycemia than gluconeogenesis, especially in those with HF, and these pathways should be considered for therapeutic targeting.

Coffee Bioactive N-Methylpyridinium: Unveiling Its Antilipogenic Effects by Targeting De Novo Lipogenesis in Human Hepatocytes.

SCOPE: Type 2 diabetes and nonalcoholic fatty liver diseases (NAFLDs) are promoted by insulin resistance (IR), which alters lipid homeostasis in the liver. This study aims to investigate the effect of N-methylpyridinium (NMP), a bioactive alkaloid of coffee brew, on lipid metabolism in hepatocytes. METHODS AND RESULTS: The effect of NMP in modulating lipid metabolism is evaluated at physiological concentrations in a diabetes cell model represented by HepG2 cells cultured in a high-glucose medium. Hyperglycemia triggers lipid droplet accumulation in cells and enhances the lipogenic gene expression, which is transactivated by sterol regulatory element binding protein-1 (SREBP-1). Lipid droplet accumulation alters the redox status and endoplasmic reticulum (ER) stress, leading to the activation of the unfolded protein response and antioxidative pathways by X-Box Binding Protein 1(XBP-1)/eukaryotic Initiation Factor 2 alpha (eIF2α) Protein Kinase RNA-Like ER Kinase and nuclear factor erythroid 2-related factor 2 (NRF2), respectively. NMP induces the phosphorylation of AMP-dependent protein kinase (AMPK) and acetyl-CoA carboxylase α (ACACA), and improves the redox status and ER homeostasis, essential steps to reduce lipogenesis and lipid droplet accumulation. CONCLUSION: These results suggest that NMP may be beneficial for the management of T2D and NAFLD by ameliorating the cell oxidative and ER homeostasis and lipid metabolism.

ER-mitochondria contact sites regulate hepatic lipogenesis via Ip3r-Grp75-Vdac complex recruiting Seipin.

BACKGROUND: Mitochondria and endoplasmic reticulum (ER) contact sites (MERCS) constitute a functional communication platform for ER and mitochondria, and they play a crucial role in the lipid homeostasis of the liver. However, it remains unclear about the exact effects of MERCs on the neutral lipid synthesis of the liver. METHODS: In this study, the role and mechanism of MERCS in palmitic acid (PA)-induced neutral lipid imbalance in the liver was explored by constructing a lipid metabolism animal model based on yellow catfish. Given that the structural integrity of MERCS cannot be disrupted by the si-mitochondrial calcium uniporter (si-mcu), the MERCS-mediated Ca2+ signaling in isolated hepatocytes was intercepted by transfecting them with si-mcu in some in vitro experiments. RESULTS: The key findings were: (1) Hepatocellular MERCs sub-proteome analysis confirmed that, via activating Ip3r-Grp75-voltage-dependent anion channel (Vdac) complexes, excessive dietary PA intake enhanced hepatic MERCs. (2) Dietary PA intake caused hepatic neutral lipid deposition by MERCs recruiting Seipin, which promoted lipid droplet biogenesis. (3) Our findings provide the first proof that MERCs recruited Seipin and controlled hepatic lipid homeostasis, depending on Ip3r-Grp75-Vdac-controlled Ca2+ signaling, apart from MERCs's structural integrity. Noteworthy, our results also confirmed these mechanisms are conservative from fish to mammals. CONCLUSIONS: The findings of this study provide a new insight into the regulatory role of MERCS-recruited SEIPIN in hepatic lipid synthesis via Ip3r-Grp75-Vdac complex-mediated Ca2+ signaling, highlighting the critical contribution of MERCS in hepatic lipid homeostasis.

The Herbal Blend of Sphaeranthus indicus and Garcinia mangostana Reduces Adiposity in High-Fat Diet Obese Mice.

Obesity is swiftly becoming a global epidemic, leading to numerous metabolic disorders and substantial socio-economic burdens. Investigating natural bioactive compounds is crucial to support the use of traditional anti-obesity medications while mitigating the adverse effects. This study posited that a combination of Sphaeranthus indicus and Garcinia mangostana (Meratrim) could prevent fat accumulation in obese mice. We used 4-week-old C57BL/6NTac mice, dividing them into six groups: (1) normal diet (ND); (2) high-fat diet (HFD, 45% kcal from fat); (3-5) Meratrim150, Meratrim300, and Meratrim450 (HFD with 150, 300, and 450 mg/kg bw of Meratrim); and (6) Metformin (HFD with 150 mg/kg bw of metformin). Meratrim was administered orally each day for 20 weeks. The group receiving 450 mg/kg of Meratrim showed a significant reduction in body weight and fat mass without changes in food consumption. The Meratrim450 group had markedly lower triglyceride levels in both serum and liver. Importantly, Meratrim-supplemented mice improved lipid homeostasis by inhibiting hepatic de novo lipogenesis and activating energy catabolic pathways such as non-shivering thermogenesis in brown adipose tissue. Our results suggest that the herbal mixture of Sphaeranthus indicus and Garcinia mangostana (Meratrim) is a promising natural anti-obesity agent, owing to its efficacy in reducing body fat and enhancing lipid homeostasis.

Let-7f-5p Modulates Lipid Metabolism by Targeting Sterol Regulatory Element-Binding Protein 2 in Response to PRRSV Infection.

Porcine reproductive and respiratory syndrome (PRRS) has caused substantial damage to the pig industry. MicroRNAs (miRNAs) were found to play crucial roles in modulating the pathogenesis of PRRS virus (PRRSV). In the present study, we revealed that PRRSV induced let-7f-5p to influence lipid metabolism to regulate PRRSV pathogenesis. A transcriptome analysis of PRRSV-infected PK15CD163 cells transfected with let-7f-5p mimics or negative control (NC) generated 1718 differentially expressed genes, which were primarily associated with lipid metabolism processes. Furthermore, the master regulator of lipogenesis SREBP2 was found to be directly targeted by let-7f-5p using a dual-luciferase reporter system and Western blotting. The findings demonstrate that let-7f-5p modulates lipogenesis by targeting SREBP2, providing novel insights into miRNA-mediated PRRSV pathogenesis and offering a potential antiviral therapeutic target.

Lacticaseibacillus paracsei HY7207 Alleviates Hepatic Steatosis, Inflammation, and Liver Fibrosis in Mice with Non-Alcoholic Fatty Liver Disease.

Non-alcoholic fatty acid disease (NAFLD) is caused by a build-up of fat in the liver, inducing local inflammation and fibrosis. We evaluated the effects of probiotic lactic acid-generating bacteria (LAB) derived from a traditional fermented beverage in a mouse model of NAFLD. The LAB isolated from this traditional Korean beverage were screened using the human hepatic cell line HepG2, and Lactocaseibacillus paracasei HY7207 (HY7207), which was the most effective inhibitor of fat accumulation, was selected for further study. HY7207 showed stable productivity in industrial-scale culture. Whole-genome sequencing of HY7207 revealed that the genome was 2.88 Mbp long, with 46.43% GC contents and 2778 predicted protein-coding DNA sequences (CDSs). HY7207 reduced the expression of lipogenesis and hepatic apoptosis-related genes in HepG2 cells treated with palmitic acid. Furthermore, the administration of 109 CFU/kg/day of HY7207 for 8 weeks to mice fed an NAFLD-inducing diet improved their physiologic and serum biochemical parameters and ameliorated their hepatic steatosis. In addition, HY7207 reduced the hepatic expression of genes important for lipogenesis (Srebp1c, Fasn, C/ebpa, Pparg, and Acaca), inflammation (Tnf, Il1b, and Ccl2), and fibrosis (Col1a1, Tgfb1, and Timp1). Finally, HY7207 affected the expression of the apoptosis-related genes Bax (encoding Bcl2 associated X, an apoptosis regulator) and Bcl2 (encoding B-cell lymphoma protein 2) in the liver. These data suggest that HY7207 consumption ameliorates NAFLD in mice through effects on liver steatosis, inflammation, fibrosis, and hepatic apoptosis. Thus, L. paracasei HY7207 may be suitable for use as a functional food supplement for patients with NAFLD.

Melatonin prevents glyphosate-induced hepatic lipid accumulation in roosters via activating Nrf2 pathway.

BACKGROUND: Glyphosate (GLY) is a widely used herbicide with well-defined hepatotoxic effects, in which oxidative stress has been shown to be involved in the pathogenesis of hepatotoxicity. Melatonin (MET), an effective free radical scavenger, has been revealed to alleviate drug-induced liver damage by inhibiting oxidative stress. METHODS: In this study, a rooster model with primary chicken embryo hepatocytes was applied to elucidate the therapeutic effects of MET against GLY-induced hepatic damage and the potential mechanism. Histopathological examinations, biochemical tests and immunoblotting analysis were used to monitor the protective effects of MET on GLY-induced hepatic lipid accumulation. Molecular docking analysis was used to reveal the key reason of MET-improved hepatic lipid deposition. RESULTS: Data firstly showed that MET administration markedly improved GLY-induced hepatic injury, as evidenced by normalized liver enzymes and alleviated pathological changes of liver tissues. Moreover, MET supplementation alleviated GLY-induced hepatic lipid accumulation, which was correlated with improved serum and hepatic lipid profiles and normalized expression of lipolysis- and lipogenesis-related proteins. Notably, MET significantly inhibited vital enzymes involved in stimulating oxidative stress. Moreover, MET enhanced GLY-inhibited Nrf2 nuclear transcription and increased the expressions of its downstream target genes HO1 and NQO1. Further studies revealed that MET may interact with Nrf2 to enhance nuclear translocation of Nrf2. CONCLUSION: Collectively, our results provide the first direct evidence that MET is a novel regulator of Nrf2, highlighting that Nrf2 may be a potential therapeutic target for GLY-induced lipotoxic liver injury.

Transcriptional Regulation of De Novo Lipogenesis by SIX1 in Liver Cancer Cells.

De novo lipogenesis (DNL), a hallmark of cancer, facilitates tumor growth and metastasis. Therapeutic drugs targeting DNL are being developed. However, how DNL is directly regulated in cancer remains largely unknown. Here, transcription factor sine oculis homeobox 1 (SIX1) is shown to directly increase the expression of DNL-related genes, including ATP citrate lyase (ACLY), fatty acid synthase (FASN), and stearoyl-CoA desaturase 1 (SCD1), via histone acetyltransferases amplified in breast cancer 1 (AIB1) and lysine acetyltransferase 7 （HBO1/KAT7）, thus promoting lipogenesis. SIX1 expression is regulated by insulin/lncRNA DGUOK-AS1/microRNA-145-5p axis, which also modulates DNL-related gene expression as well as DNL. The DGUOK-AS1/microRNA-145-5p/SIX1 axis regulates liver cancer cell proliferation, invasion, and metastasis in vitro and in vivo. In patients with liver cancer, SIX1 expression is positively correlated with DGUOK-AS1 and SCD1 expression and is negatively correlated with microRNA-145-5p expression. DGUOK-AS1 is a good predictor of prognosis. Thus, the DGUOK-AS1/microRNA-145-5p/SIX1 axis strongly links DNL to tumor growth and metastasis and may become an avenue for liver cancer therapeutic intervention.

FABP1 induces lipogenesis by regulating the processing of SREBP1 in hepatocytes of large yellow croaker (Larimichthys crocea).

Fatty acid-binding protein 1 (FABP1) plays an important role in regulating fatty acid metabolism in liver, which is a potential therapeutic target for diseases such as non-alcoholic fatty liver disease (NAFLD). However, the underlying mechanisms are not well defined. Using complementary experimental models, we discovered FABP1 induction in hepatocytes as a primary mediator of lipogenesis when exposed to fatty acids, especially saturated fatty acids (SFAs). In the feeding trial, palm oil led to excess lipid accumulation in the liver of large yellow croaker (Larimichthys crocea), accompanied by significant induction of FABP1. In cultured cells, palmitic acid (PA), a kind of SFA, triggered the fabp1 expression and increased triglyceride (TG) contents. Knockdown of FABP1 dampened PA-induced TG accumulation through mitigated lipogenesis. The overexpression of FABP1 showed the opposite result. Furthermore, the inactivation of FABP1 led to induction in insulin-induced gene 1 (INSIG1) expression, which attenuated the processing of sterol regulatory element-binding protein 1 (SREBP1) by down-regulating the nuclear-localized SREBP1. These results revealed a previously unrecognized function of FABP1 in response to PA, providing additional evidence for targeting FABP1 in the treatment of NAFLD caused by SFA.

Structure based exploration of mitochondrial alpha carbonic anhydrase inhibitors as potential leads for anti-obesity drug development.

BACKGROUND: Obesity has emerged as a major health challenge globally in the last two decades. Dysregulated fatty acid metabolism and de novo lipogenesis are prime causes for obesity development which ultimately trigger other co-morbid pathological conditions thereby risking life longevity. Fatty acid metabolism and de novo lipogenesis involve several biochemical steps both in cytosol and mitochondria. Reportedly, the high catalytically active mitochondrial carbonic anhydrases (CAVA/CAVB) regulate the intercellular depot of bicarbonate ions and catalyze the rapid carboxylation of pyruvate and acetyl-co-A to acetyl-co-A and malonate respectively, which are the precursors of fatty acid synthesis and lipogenesis. Several in vitro and in vivo investigations indicate inhibition of mitochondrial carbonic anhydrase isoforms interfere in the functioning of pyruvate, fatty acid and succinate pathways. Targeting of mitochondrial carbonic anhydrase isoforms (CAVA/CAVB) could thereby modulate gluconeogenetic as well as lipogenetic pathways and pave way for designing of novel leads in the development pipeline of anti-obesity medications. METHODS: The present review unveils a diverse chemical space including synthetic sulphonamides, sulphamates, sulfamides and many natural bioactive molecules which selectively inhibit the mitochondrial isoform CAVA/CAVB with an emphasis on major state-of-art drug design strategies. RESULTS: More than 60% similarity in the structural framework of the carbonic anhydrase isoforms has converged the drug design methods towards the development of isoform selective chemotypes. While the benzene sulphonamide derivatives selectively inhibit CAVA/CAVB in low nanomolar ranges depending on the substitutions on the phenyl ring, the sulpamates and sulpamides potently inhibit CAVB. The virtual screening and drug repurposing methods have also explored many non-sulphonamide chemical scaffolds which can potently inhibit CAVA. CONCLUSION: The review could pave way for the development of novel and effective anti-obesity drugs which can modulate the energy metabolism.