Carbohydrate response element binding protein, ChREBP, a transcription factor coupling hepatic glucose utilization and lipid synthesis

Integrated metabolomic and transcriptomic analysis reveals the effects and mechanisms of Jinqi Jiangtang tablets on type 2 diabetes

BACKGROUND

Type 2 diabetes (T2DM) is one of the major metabolic diseases and poses a serious challenge to human life and global economic development. Jinqi Jiangtang Tablets (JQJT) is effective in ameliorating the effects of T2DM, but the mechanism of JQJT is unclear.

PURPOSE

This study integrated metabolomics and transcriptomics to reveal the mechanism by which JQJT improves T2DM.

METHODS

The T2DM mouse model was established, and the effects of JQJT on improving T2DM were evaluated by determining the levels of blood lipids, fasting blood glucose (FBG), insulin metabolism and hepatic lipid accumulation in mice after JQJT administration for 8 weeks. Serum metabolites were detected using ultra-performance liquid chromatography/quadrupole time-of-flight-tandem mass spectrometry (UPLC-Q-TOF-MS) technology, and mouse liver differential genes were detected using transcriptomic technology. Correlation analysis was used to extract metabolites and RNA with correlations, and potential pathways were enriched and constructed using the common pathway analysis function of MetaboAnalyst 5.0. Finally, the expression of key target proteins and genes was verified by Western blot (WB) and Polymerase Chain Reaction (PCR) to further elucidate the mechanism by which JQJT improves T2DM.

RESULTS

JQJT reduced FBG and lipid levels, improved insulin resistance (IR) and hepatic lipoatrophy in mice. A total of 35 differentially abundant metabolites were identified by metabolomics, and 328 differential genes were detected by transcriptomics. The integrated metabolomics and transcriptomics results suggested that JQJT may ameliorate T2DM mainly by regulating glucose and lipid metabolic pathways. WB and PCR results showed that JQJT regulates the insulin signaling pathway, involved in fatty acid metabolism, glycogen synthesis and catabolism.

CONCLUSIONS

JQJT improved IR in T2DM mice by regulating the insulin signaling pathway, improving glycogen synthesis and glycolysis, and increasing hepatic triglyceride and fatty acid metabolism.

O-GlcNAcylation of ATP-citrate lyase couples glucose supply to lipogenesis for rapid tumor cell proliferation

Elevated lipid synthesis is one of the best-characterized metabolic alterations in cancer and crucial for membrane expansion. As a key rate-limiting enzyme in de novo fatty acid synthesis, ATP-citrate lyase (ACLY) is frequently up-regulated in tumors and regulated by posttranslational modifications (PTMs). Despite emerging evidence showing O-GlcNAcylation on ACLY, its biological function still remains unknown. Here, we observed a significant upregulation of ACLY O-GlcNAcylation in various types of human tumor cells and tissues and identified S979 as a major O-GlcNAcylation site. Importantly, S979 O-GlcNAcylation is required for substrate CoA binding and crucial for ACLY enzymatic activity. Moreover, it is sensitive to glucose fluctuation and decisive for fatty acid synthesis as well as tumor cell proliferation. In response to EGF stimulation, both S979 O-GlcNAcylation and previously characterized S455 phosphorylation played indispensable role in the regulation of ACLY activity and cell proliferation; however, they functioned independently from each other. In vivo, streptozocin treatment- and EGFR overexpression-induced growth of xenograft tumors was mitigated once S979 was mutated. Collectively, this work helps comprehend how cells interrogate the nutrient enrichment for proliferation and suggests that although mammalian cell proliferation is controlled by mitogen signaling, the ancient nutrition-sensing mechanism is conserved and still efficacious in the cells of multicellular organisms.

Diet predisposes to pancreatic cancer through cellular nutrient sensing pathways

Pancreatic cancer is a lethal disease with limited effective treatments. A deeper understanding of its molecular mechanisms is crucial to reduce incidence and mortality. Epidemiological evidence suggests a link between diet and disease risk, though dietary recommendations for at-risk individuals remain debated. Here, we propose that cell-intrinsic nutrient sensing pathways respond to specific diet-derived cues to facilitate oncogenic transformation of pancreatic epithelial cells. This review explores how diet influences pancreatic cancer predisposition through nutrient sensing and downstream consequences for (pre-)cancer cell biology. We also examine experimental evidence connecting specific food intake to pancreatic cancer progression, highlighting nutrient sensing as a promising target for therapeutic development to mitigate disease risk.

Hepatic glucokinase regulatory protein and carbohydrate response element binding protein attenuation reduce de novo lipogenesis but do not mitigate intrahepatic triglyceride accumulation in Aldob deficiency

OBJECTIVE

Stable isotope studies have shown that hepatic de novo lipogenesis (DNL) plays an important role in the pathogenesis of intrahepatic lipid (IHL) deposition. Furthermore, previous research has demonstrated that fructose 1-phosphate (F1P) not only serves as a substrate for DNL, but also acts as a signalling metabolite that stimulates DNL from glucose. The aim of this study was to elucidate the mediators of F1P-stimulated DNL, with special focus on two key regulators of intrahepatic glucose metabolism, i.e., glucokinase regulatory protein (GKRP) and carbohydrate response element binding protein (ChREBP).

METHODS

Aldolase B deficient mice (Aldob-/-), characterized by hepatocellular F1P accumulation, enhanced DNL, and hepatic steatosis, were either crossed with GKRP deficient mice (Gckr-/-) or treated with short hairpin RNAs directed against hepatic ChREBP.

RESULTS

Aldob-/- mice showed higher rates of de novo palmitate synthesis from glucose when compared to wildtype mice (p < 0.001). Gckr knockout reduced de novo palmitate synthesis in Aldob-/- mice (p = 0.017), without affecting the hepatic mRNA expression of enzymes involved in DNL. In contrast, hepatic ChREBP knockdown normalized the hepatic mRNA expression levels of enzymes involved in DNL and reduced fractional DNL in Aldob-/- mice (p < 0.05). Of interest, despite downregulation of DNL in response to Gckr and ChREBP attenuation, no reduction in intrahepatic triglyceride levels was observed.

CONCLUSIONS

Both GKRP and ChREBP mediate F1P-stimulated DNL in aldolase B deficient mice. Further studies are needed to unravel the role of GKRP and hepatic ChREBP in regulating IHL accumulation in aldolase B deficiency.

Activation of skeletal carbohydrate-response element binding protein (ChREBP)-mediated de novo lipogenesis increases intramuscular fat content in chickens

The intracellular lipids in muscle cells of farm animals play a crucial role in determining the overall intramuscular fat (IMF) content, which has a positive impact on meat quality. However, the mechanisms underlying the deposition of lipids in muscle cells of farm animals are not yet fully understood. The purpose of this study was to determine the roles of carbohydrate-response element binding protein (ChREBP) and fructose in IMF deposition of chickens. For virus-mediated ChREBP overexpression in tibialis anterior (TA) muscle of chickens, seven 5-d-old male yellow-feather chickens were used. At 10 d after virus injection, the chickens were slaughtered to obtain TA muscles for analysis. For fructose administration trial, sixty 9-wk-old male yellow-feather chickens were randomly divided into 2 groups, with 6 replicates per group and 5 chickens per replicate. The chickens were fed either a basal diet or a basal diet supplemented with 10% fructose (purity ≥ 99%). At 4 wk later, the chickens were slaughtered, and breast and thigh muscles were collected for analysis. The results showed that the skeletal ChREBP mRNA levels were positively associated with IMF content in multiple species, including the chickens, pigs, and mice (P < 0.05). ChREBP overexpression increased lipid accumulation in both muscle cells in vitro and the TA muscles of mice and chickens in vivo (P < 0.05), by activation of the de novo lipogenesis (DNL) pathway. Moreover, activation of ChREBP by dietary fructose administration also resulted in increased IMF content in mice and notably chickens (P < 0.05). Furthermore, the lipidomics analysis revealed that ChREBP activation altered the lipid composition of chicken IMF and tented to improve the flavor profile of the meat. In conclusion, this study found that ChREBP plays a pivotal role in mediating the deposition of fat in chicken muscles in response to fructose-rich diets, which provides a novel strategy for improving meat quality in the livestock industry.

Systemic identification of functionally conserved lncRNA metabolic regulators in human and mouse livers

BACKGROUND & AIMS

Unlike protein-coding genes, the majority of human long non-coding RNAs (lncRNAs) lack conservation based on their sequences, posing a challenge for investigating their role in a pathophysiological context for clinical translation. This study explores the hypothesis that non-conserved lncRNAs in human and mouse livers may share similar metabolic functions, giving rise to functionally conserved lncRNA metabolic regulators (fcLMRs).

METHODS

We developed a sequence-independent strategy to select putative fcLMRs, and performed extensive analysis to determine the functional similarities of putative human and mouse LMR pairs (h/mLMRs).

RESULTS

We found that several pairs of putative fcLMRs share similar functions in regulating gene expression. We further demonstrated that a pair of fcLMRs, h/mLMR1, robustly regulated triglyceride levels by modulating the expression of a similar set of lipogenic genes. Mechanistically, h/mLMR1 binds to PABPC1, a regulator of protein translation, via short motifs on either lncRNA with divergent sequences but similar structures. This interaction inhibits protein translation, activating an amino acid-mTOR-SREBP1 axis to regulate lipogenic gene expression. Intriguingly, PABPC1-binding motifs on each lncRNA fully rescued the functions of their corresponding LMRs in the opposite species. Given the elevated expression of h/mLMR1 in humans and mice with hepatic steatosis, the PABPC1-binding motif on hLMR1 emerges as a potential non-conserved human drug target whose functions can be fully validated in a physiologically relevant setting before clinical studies.

CONCLUSIONS

Our study supports that fcLMRs represent a novel and prevalent biological phenomenon, and deep phenotyping of genetic mLMR mouse models constitutes a powerful approach to understand the pathophysiological role of lncRNAs in the human liver.

Hepatic Steatosis Can Be Partly Generated by the Gut Microbiota-Mitochondria Axis via 2-Oleoyl Glycerol and Reversed by a Combination of Soy Protein, Chia Oil, Curcumin and Nopal

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a serious health problem, and recent evidence indicates that gut microbiota plays a key role in its development. It is known that 2-oleoyl glycerol (2-OG) produced by the gut microbiota is associated with hepatic fibrosis, but it is not known whether this metabolite is involved in the development of hepatic steatosis. The aim of this study was to evaluate how a high-fat-sucrose diet (HFS) increases 2-OG production through gut microbiota dysbiosis and to identify whether this metabolite modifies hepatic lipogenesis and mitochondrial activity for the development of hepatic steatosis as well as whether a combination of functional foods can reverse this process. Wistar rats were fed the HFS diet for 7 months. At the end of the study, body composition, biochemical parameters, gut microbiota, protein abundance, lipogenic and antioxidant enzymes, hepatic 2-OG measurement, and mitochondrial function of the rats were evaluated. Also, the effect of the consumption of functional food with an HFS diet was assessed. In humans with MASLD, we analyzed gut microbiota and serum 2-OG. Consumption of the HFS diet in Wistar rats caused oxidative stress, hepatic steatosis, and gut microbiota dysbiosis, decreasing α-diversity and increased Blautia producta abundance, which increased 2-OG. This metabolite increased de novo lipogenesis through ChREBP and SREBP-1. 2-OG significantly increased mitochondrial dysfunction. The addition of functional foods to the diet modified the gut microbiota, reducing Blautia producta and 2-OG levels, leading to a decrease in body weight gain, body fat mass, serum glucose, insulin, cholesterol, triglycerides, fatty liver formation, and increased mitochondrial function. To use 2-OG as a biomarker, this metabolite was measured in healthy subjects or with MASLD, and it was observed that subjects with hepatic steatosis II and III had significantly higher 2-OG than healthy subjects, suggesting that the abundance of this circulating metabolite could be a predictor marker of hepatic steatosis.

Liquorice root extract and isoliquiritigenin attenuate high-fat diet-induced hepatic steatosis and damage in rats by regulating AMPK

Objective: This study compared the ability of Liquorice roots aqueous extract (LRE) and its ingredient, isoliquiritigenin (ISL), in alleviating high-fat diet (HFD)-induced hepatic steatosis and examined if this effect involves activation of AMPK.Materials and methods: Control or HFD-fed rats were treated with the vehicle, LRE (200 mg/kg), or ISL (30 mg/kg) for 8 weeks orally.Results: ISL and LRE reduced HFD-induced hyperglycaemia, improved liver structure, lowered serum and hepatic lipids, and attenuated hepatic oxidative stress and inflammation. In the control and HFD-fed rats, ISL and LRE significantly stimulated the muscular and hepatic mRNA and protein levels of AMPK, improved oral glucose tolerance, reduced hepatic mRNA levels of SREBP1/2, and upregulated hepatic levels of PPARα and Bcl2. These effects were comparable for ISL and LRE and were prevented by co-administration of compound C, an AMPK inhibitor.Discussion and conclusion: ISL and LRE provide an effective theory to alleviate hepatic steatosis through activating AMPK.

Sesaminol alters phospholipid metabolism and alleviates obesity-induced NAFLD

The prevalence of obesity-induced non-alcoholic fatty liver disease (NAFLD) and insulin resistance is increasing worldwide. We previously demonstrated that sesaminol increases thermogenesis in adipocytes, improves insulin sensitivity, and mitigates obesity in mice. In this study, we demonstrated that sesaminol increased mitochondrial activity and reduced ROS production in hepatocytes. Therefore, we delve into the metabolic action of sesaminol in obesity-induced NAFLD or metabolic dysfunction-associated liver disease (MAFLD). Here, we report that sesaminol induces OXPHOS proteins and mitochondrial function in vivo. Further, our data suggest that sesaminol administration reduces hepatic triacylglycerol accumulation and LDL-C levels. Prominently, the lipidomics analyses revealed that sesaminol administration decreased the major phospholipids such as PC, PE, PI, CL, and PS to maintain membrane lipid homeostasis in the liver upon HFD challenge. Besides, SML reduced ePC and SM molecular species and increased PA levels in the HFD-fed mice. Also, sesaminol renders anti-inflammatory properties and dampens fibrosis markers in the liver. Remarkably, SML lowers the hepatic levels of ALT and AST enzymes and alleviates NAFLD in diet-induced obese mice. The molecular docking analysis identifies peroxisome proliferator-activated receptors as potential endogenous receptors for sesaminol. Together, our study demonstrates plant lignan sesaminol as a potential small molecule that alters the molecular species of major phospholipids, including sphingomyelin and ether-linked PCs in the liver tissue, improves metabolic parameters, and alleviates obesity-induced fatty liver disease in mice.

Resveratrol attenuates against high-fat-diet-promoted non-alcoholic fatty liver disease in rats mainly by targeting the miR-34a/SIRT1 axis

This study evaluated if miR-34a/SIRT1 signalling mediates the anti-hepatosteatotic effect of resveratrol (RSV) in high-fat-diet (HFD)-fed rats. Rats were divided into seven groups (n = 6/each) as control, control + miR-34a agomir negative control, HFD, HFD + miR-34a, HFD + RSV, HFD + RSV + Ex-527 (a SIRT1 inhibitor), and HFD + RSV + miR-34a agomir. After 8 weeks, RSV suppressed dyslipidemia, lowered fasting glucose and insulin levels, improved insulin sensitivity, and prevented hepatic lipid accumulation. These effects were associated with hepatic downregulation of SREBP1 and SREBP2, upregulation of PPARα, and acetylation of Nrf2 (activation) and NF-κβ p65 (inhibition). Also, RSV reduced the transcription of miR-34a and increased the nuclear localisation of SIRT1 in the livers, muscles, and adipose tissues of HFD-fed rats. All these effects were prevented by EX-527 and miR-34a agmir. In conclusion, RSV prevents HFD-induced insulin resistance and hepatic steatosis by suppressing miR-34a-induced activation of SIRT1.

Comprehensive study of the interplay between immunological and metabolic factors in hepatic steatosis

The pathophysiology of hepatic steatosis is thoroughly reviewed in this comprehensive report, with particular attention to the complex interactions between inflammatory pathways, insulin resistance, lipid metabolism, metabolic dysregulation, and immunological responses in the liver including non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), and hepatocellular carcinoma (HCC). The study highlights the role of immune cell regulation in disease progression and explores the potential of immune cell-specific treatments for treating hepatic disorders. The development of liver disorders is significantly influenced by immune cells, including dendritic cells, T cells, and natural killer cells. Clinical investigations show that immune cell-specific treatments can effectively reduce liver fibrosis and inflammation. Future research should focus on finding new immunological targets for therapeutic interventions, as well as addressing the management challenges associated with NAFLD/NASH. Hepatic immune microorganisms also impact liver homeostasis and disorders. Improvements in immune cell regulation and liver transplantation methods give patients hope for better prognoses. Important phases include optimizing the selection of donors for malignancy of the liver, using machine perfusion for organ preservation, and fine-tuning immunosuppressive strategies. For focused treatments in hepatic steatosis, it is imperative to understand the intricate interactions between immune and metabolic variables. Understanding the liver's heterogeneous immune profile, encompassing a range of immune cell subpopulations, is crucial for formulating focused therapeutic interventions. To improve patient care and outcomes in hepatic illnesses, there is an urgent need for further research and innovation. Therefore, to effectively treat hepatic steatosis, it is important to enhance therapeutic techniques and maximize liver transplantation strategies.

Metabolic Dysfunction-Associated Steatotic Liver Disease: From Pathogenesis to Current Therapeutic Options

The epidemiological burden of liver steatosis associated with metabolic diseases is continuously growing worldwide and in all age classes. This condition generates possible progression of liver damage (i.e., inflammation, fibrosis, cirrhosis, hepatocellular carcinoma) but also independently increases the risk of cardio-metabolic diseases and cancer. In recent years, the terminological evolution from "nonalcoholic fatty liver disease" (NAFLD) to "metabolic dysfunction-associated fatty liver disease" (MAFLD) and, finally, "metabolic dysfunction-associated steatotic liver disease" (MASLD) has been paralleled by increased knowledge of mechanisms linking local (i.e., hepatic) and systemic pathogenic pathways. As a consequence, the need for an appropriate classification of individual phenotypes has been oriented to the investigation of innovative therapeutic tools. Besides the well-known role for lifestyle change, a number of pharmacological approaches have been explored, ranging from antidiabetic drugs to agonists acting on the gut-liver axis and at a systemic level (mainly farnesoid X receptor (FXR) agonists, PPAR agonists, thyroid hormone receptor agonists), anti-fibrotic and anti-inflammatory agents. The intrinsically complex pathophysiological history of MASLD makes the selection of a single effective treatment a major challenge, so far. In this evolving scenario, the cooperation between different stakeholders (including subjects at risk, health professionals, and pharmaceutical industries) could significantly improve the management of disease and the implementation of primary and secondary prevention measures. The high healthcare burden associated with MASLD makes the search for new, effective, and safe drugs a major pressing need, together with an accurate characterization of individual phenotypes. Recent and promising advances indicate that we may soon enter the era of precise and personalized therapy for MASLD/MASH.

Sterol Regulatory Element Binding Protein 1: A Mediator for High-Fat Diet-Induced Hepatic Gluconeogenesis and Glucose Intolerance in Fish

BACKGROUND

Sterol regulatory element binding protein (SREBP) 1 is considered to be a crucial regulator for lipid synthesis in vertebrates. However, whether SREBP1 could regulate hepatic gluconeogenesis under high-fat diet (HFD) condition is still unknown, and the underlying mechanism is also unclear.

OBJECTIVES

This study aimed to determine gluconeogenesis-related gene and protein expressions in response to HFD in large yellow croaker and explore the role and mechanism of SREBP1 in regulating the related transcription and signaling.

METHODS

Croakers (mean weight, 15.61 ± 0.10 g) were fed with diets containing 12% crude lipid [control diet (ND)] or 18% crude lipid (HFD) for 10 weeks. The glucose tolerance, insulin tolerance, hepatic gluconeogenesis-related genes, and proteins expressions were determined. To explore the role of SREBP1 in HFD-induced gluconeogenesis, SREBP1 was inhibited by pharmacologic inhibitor (fatostatin) or genetic knockdown in croaker hepatocytes under palmitic acid (PA) condition. To explore the underlying mechanism, luciferase reporter and chromatin immunoprecipitation assays were conducted in HEK293T cells. Data were analyzed using analysis of variance or Student t test.

RESULTS

Compared with ND, HFD increased the mRNA expressions of gluconeogenesis genes (2.40-fold to 2.60-fold) (P < 0.05) and reduced protein kinase B (AKT) phosphorylation levels (0.28-fold to 0.34-fold) (P < 0.05) in croakers. However, inhibition of SREBP1 by fatostatin addition or SREBP1 knockdown reduced the mRNA expressions of gluconeogenesis genes (P < 0.05) and increased AKT phosphorylation levels (P < 0.05) in hepatocytes, compared with that by PA treatment. Moreover, fatostatin addition or SREBP1 knockdown also increased the mRNA expressions of irs1 (P < 0.05) and reduced serine phosphorylation of IRS1 (P < 0.05). Furthermore, SREBP1 inhibited IRS1 transcriptions by binding to its promoter and induced IRS1 serine phosphorylation by activating diacylglycerol-protein kinase Cε signaling.

CONCLUSIONS

This study reveals the role of SREBP1 in hepatic gluconeogenesis under HFD condition in croakers, which may provide a potential strategy for improving HFD-induced glucose intolerance.

A genome-first approach to variants in MLXIPL and their association with hepatic steatosis and plasma lipids

BACKGROUND

Common variants of the max-like protein X (MLX)-interacting protein-like (MLXIPL) gene, encoding the transcription factor carbohydrate-responsive element-binding protein, have been shown to be associated with plasma triglyceride levels. However, the role of these variants in steatotic liver disease (SLD) is unclear.

METHODS

We used a genome-first approach to analyze a variety of metabolic phenotypes and clinical outcomes associated with a common missense variant in MLXIPL, Gln241His, in 2 large biobanks: the UK Biobank and the Penn Medicine Biobank.

RESULTS

Carriers of MLXIPL Gln241His were associated with significantly lower serum levels of triglycerides, apolipoprotein-B, gamma-glutamyl transferase, and alkaline phosphatase. Additionally, MLXIPL Gln241His carriers were associated with significantly higher serum levels of HDL cholesterol and alanine aminotransferase. Carriers homozygous for MLXIPL Gln241His showed a higher risk of SLD in 2 unrelated cohorts. Carriers of MLXIPL Gln241His were especially more likely to be diagnosed with SLD if they were female, obese, and/or also carried the PNPLA3 I148M variant. Furthermore, the heterozygous carriage of MLXIPL Gln241His was associated with significantly higher all-cause, liver-related, and cardiovascular mortality rates. Nuclear magnetic resonance metabolomics data indicated that carriage of MLXIPL Gln241His was significantly associated with lower serum levels of VLDL and increased serum levels of HDL cholesterol.

CONCLUSIONS

Analyses of the MLXIPL Gln241His polymorphism showed a significant association with a higher risk of SLD diagnosis and elevated serum alanine aminotransferase as well as significantly lower serum triglycerides and apolipoprotein-B levels. MLXIPL might, therefore, be a potential pharmacological target for the treatment of SLD and hyperlipidemia, notably for patients at risk. More mechanistic studies are needed to better understand the role of MLXIPL Gln241His on lipid metabolism and steatosis development.

Advances in management of metabolic dysfunction-associated steatotic liver disease: from mechanisms to therapeutics

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the leading cause of chronic liver disease that affects over 30% of the world's population. For decades, the heterogeneity of non-alcoholic fatty liver disease (NAFLD) has impeded our understanding of the disease mechanism and the development of effective medications. However, a recent change in the nomenclature from NAFLD to MASLD emphasizes the critical role of systemic metabolic dysfunction in the pathophysiology of this disease and therefore promotes the progress in the pharmaceutical treatment of MASLD. In this review, we focus on the mechanism underlying the abnormality of hepatic lipid metabolism in patients with MASLD, and summarize the latest progress in the therapeutic medications of MASLD that target metabolic disorders.

Changes in Cells Associated with Insulin Resistance

Insulin is a polypeptide hormone synthesized and secreted by pancreatic β-cells. It plays an important role as a metabolic hormone. Insulin influences the metabolism of glucose, regulating plasma glucose levels and stimulating glucose storage in organs such as the liver, muscles and adipose tissue. It is involved in fat metabolism, increasing the storage of triglycerides and decreasing lipolysis. Ketone body metabolism also depends on insulin action, as insulin reduces ketone body concentrations and influences protein metabolism. It increases nitrogen retention, facilitates the transport of amino acids into cells and increases the synthesis of proteins. Insulin also inhibits protein breakdown and is involved in cellular growth and proliferation. On the other hand, defects in the intracellular signaling pathways of insulin may cause several disturbances in human metabolism, resulting in several chronic diseases. Insulin resistance, also known as impaired insulin sensitivity, is due to the decreased reaction of insulin signaling for glucose levels, seen when glucose use in response to an adequate concentration of insulin is impaired. Insulin resistance may cause, for example, increased plasma insulin levels. That state, called hyperinsulinemia, impairs metabolic processes and is observed in patients with type 2 diabetes mellitus and obesity. Hyperinsulinemia may increase the risk of initiation, progression and metastasis of several cancers and may cause poor cancer outcomes. Insulin resistance is a health problem worldwide; therefore, mechanisms of insulin resistance, causes and types of insulin resistance and strategies against insulin resistance are described in this review. Attention is also paid to factors that are associated with the development of insulin resistance, the main and characteristic symptoms of particular syndromes, plus other aspects of severe insulin resistance. This review mainly focuses on the description and analysis of changes in cells due to insulin resistance.

Physiological functions of glucose transporter-2: From cell physiology to links with diabetes mellitus

Glucose is a sugar crucial for human health since it participates in many biochemical reactions. It produces adenosine 5'-triphosphate (ATP) and nucleosides through glucose metabolic and pentose phosphate pathways. These processes require many transporter proteins to assist in transferring glucose across cells, and the most notable ones are glucose transporter-2 (GLUT-2) and sodium/glucose cotransporter 1 (SGLT1). Glucose enters small intestinal epithelial cells from the intestinal lumen by crossing the brush boundary membrane via the SGLT1 cotransporter. It exits the cells by traversing the basolateral membrane through the activity of the GLUT-2 transporter, supplying energy throughout the body. Dysregulation of these glucose transporters is involved in the pathogenesis of several metabolic diseases, such as diabetes. Natural loss of GLUT-2 or its downregulation causes abnormal blood glucose concentrations in the body, such as fasting hypoglycemia and glucose tolerance. Therefore, understanding GLUT-2 physiology is necessary for exploring the mechanisms of diabetes and targeted treatment development. This article reviews how the apical GLUT-2 transporter maintains normal physiological functions of the human body and the adaptive changes this transporter produces under pathological conditions such as diabetes.

Association between healthy beverage index and nonalcoholic fatty liver disease in the Ravansar noncommunicable disease cohort study

The quality of drinks affects the functioning of the liver. In recent decades, the variety of high-calorie and sweet drinks has increased. The objective of this study was to explore the association between Healthy Beverage Index (HBI) and the risk of nonalcoholic fatty liver disease (NAFLD) among adults. We included 6,276 participants aged 35 to 65 from the Ravansar Non-Communicable Disease (RaNCD) cohort study at baseline. NAFLD is defined based on the fatty liver index (FLI), calculated using anthropometric measurements and non-invasive markers. The HBI was developed using a combination of water, low-fat milk, 100% fruit juice, sugar-sweetened beverages, met fluid requirement and % energy from beverages. Logistic and linear regression models were employed to investigate the associations of the HBI and high FLI. The average FLI was significantly lower in the first tertile of HBI compared to the third tertile (47.83 vs. 45.77; P = 0.001). After adjusting for confounding variables, the odds of high FLI decreased by 28% (OR 0.72, 95% CI 0.63, 0.82) in the second tertile of HBI and by 21% in the third tertile (OR 0.79, 95% CI 0.70, 0.91). There was no correlation between gamma glutamyl transferase (GGT), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and aspartate transaminase (AST) levels with HBI. The study findings indicate an inverse association between high FLI and HBI. Therefore, it is recommended to consume healthy beverages and without added sugar. However, additional longitudinal studies are required to examine the association between beverage consumption and the development of NAFLD.

CDK6 inhibits de novo lipogenesis in white adipose tissues but not in the liver

Increased de novo lipogenesis (DNL) in white adipose tissue is associated with insulin sensitivity. Under both Normal-Chow-Diet and High-Fat-Diet, mice expressing a kinase inactive Cyclin-dependent kinase 6 (Cdk6) allele (K43M) display an increase in DNL in visceral white adipose tissues (VAT) as compared to wild type mice (WT), accompanied by markedly increased lipogenic transcriptional factor Carbohydrate-responsive element-binding proteins (CHREBP) and lipogenic enzymes in VAT but not in the liver. Treatment of WT mice under HFD with a CDK6 inhibitor recapitulates the phenotypes observed in K43M mice. Mechanistically, CDK6 phosphorylates AMP-activated protein kinase, leading to phosphorylation and inactivation of acetyl-CoA carboxylase, a key enzyme in DNL. CDK6 also phosphorylates CHREBP thus preventing its entry into the nucleus. Ablation of runt related transcription factor 1 in K43M mature adipocytes reverses most of the phenotypes observed in K43M mice. These results demonstrate a role of CDK6 in DNL and a strategy to alleviate metabolic syndromes.

New Insights into the Role of KLF10 in Tissue Fibrosis

Fibrosis, characterized by excessive extracellular matrix accumulation, disrupts normal tissue architecture, causes organ dysfunction, and contributes to numerous chronic diseases. This review focuses on Krüppel-like factor 10 (KLF10), a transcription factor significantly induced by transforming growth factor-β (TGF-β), and its role in fibrosis pathogenesis and progression across various tissues. KLF10, initially identified as TGF-β-inducible early gene-1 (TIEG1), is involved in key biological processes including cell proliferation, differentiation, apoptosis, and immune responses. Our analysis investigated KLF10 gene and protein structures, interaction partners, and context-dependent functions in fibrotic diseases. This review highlights recent findings that underscore KLF10 interaction with pivotal signaling pathways, such as TGF-β, and the modulation of gene expression in fibrotic tissues. We examined the dual role of KLF10 in promoting and inhibiting fibrosis depending on tissue type and fibrotic context. This review also discusses the therapeutic potential of targeting KLF10 in fibrotic diseases, based on its regulatory role in key pathogenic mechanisms. By consolidating current research, this review aims to enhance the understanding of the multifaceted role of KLF10 in fibrosis and stimulate further research into its potential as a therapeutic target in combating fibrotic diseases.

Lipid Metabolism in Metabolic-Associated Steatotic Liver Disease (MASLD)

Metabolic-associated steatotic liver disease (MASLD) is a cluster of pathological conditions primarily developed due to the accumulation of ectopic fat in the hepatocytes. During the severe form of the disease, i.e., metabolic-associated steatohepatitis (MASH), accumulated lipids promote lipotoxicity, resulting in cellular inflammation, oxidative stress, and hepatocellular ballooning. If left untreated, the advanced form of the disease progresses to fibrosis of the tissue, resulting in irreversible hepatic cirrhosis or the development of hepatocellular carcinoma. Although numerous mechanisms have been identified as significant contributors to the development and advancement of MASLD, altered lipid metabolism continues to stand out as a major factor contributing to the disease. This paper briefly discusses the dysregulation in lipid metabolism during various stages of MASLD.

Rotundic acid improves nonalcoholic steatohepatitis in mice by regulating glycolysis and the TLR4/AP1 signaling pathway

BACKGROUND

Steatosis and inflammation are the hallmarks of nonalcoholic steatohepatitis (NASH). Rotundic acid (RA) is among the key triterpenes of Ilicis Rotundae Cortex and has exhibited multipronged effects in terms of lowering the lipid content and alleviating inflammation. The study objective is to systematically evaluate the potential mechanisms through which RA affects the development and progression of NASH.

METHODS

Transcriptomic and proteomic analyses of primary hepatocytes isolated from the control, high-fat diet-induced NASH, and RA treatment groups were performed through Gene Ontology analysis and pathway enrichment. Hub genes were identified through network analysis. Integrative analysis revealed key RA-regulated pathways, which were verified by gene and protein expression studies and cell assays.

RESULTS

Hub genes were identified and enriched in the Toll-like receptor 4 (TLR4)/activator protein-1 (AP1) signaling pathway and glycolysis pathway. RA reversed glycolysis and attenuated the TLR4/AP1 pathway, thereby reducing lipid accumulation and inflammation. Additionally, lactate release in L-02 cells increased with NaAsO2-treated and significantly decreased with RA treatment, thus revealing that RA had a major impact on glycolysis.

CONCLUSIONS

RA is effective in lowering the lipid content and reducing inflammation in mice with NASH by ameliorating glycolysis and TLR4/AP1 pathways, which contributes to the existing knowledge and potentially sheds light on the development of therapeutic interventions for patients with NASH.

F6P/G6P-mediated ChREBP activation promotes the insulin resistance-driven hepatic lipid deposition in zebrafish

Insulin-sensitive lipogenesis dominates the body lipid deposition; however, nonalcoholic fatty liver disease (NAFLD) develops in the insulin-resistant state. The regulation mechanism of insulin resistance-driven NAFLD remains elusive. Using zebrafish model of insulin resistance (ZIR, insrb-/-) and mouse hepatocytes (NCTC 1469), we explored the regulation mechanism of insulin resistance-driven hepatic lipid deposition under the stimulation of carbohydrate diet (CHD). In ZIR model, insulin resistance induced hyperlipidemia and elevated hepatic lipid deposition via elevating the gene/protein expressions of lipogenic enzymes, that was activated by carbohydrate response element binding protein (ChREBP), rather than sterol regulatory element binding proteins 1c (SREBP-1c). The metabolomic analysis in zebrafish and silencing of chrebp in mouse hepatocytes revealed that the increased hepatic frucotose-6-phosphate (F6P) and glucose-6-phosphate (G6P) promoted the ChREBP-mediated lipid deposition. We further identified that F6P alone was sufficient to activate ChREBP-mediated lipid deposition by a SREBP-1c-independent manner. Moreover, we clarified the suppressed hepatic phosphofructokinase/glucose-6-phosphatase functions and the normal glucokinase function preserved by glucose transporter 2 (GLUT2) manipulated the increased F6P/G6P content in ZIR. In conclusion, the present study revealed that insulin resistance promoted hepatic lipid deposition via the F6P/G6P-mediated ChREBP activation. Our findings deciphered the main regulation pathway for the liver lipid deposition in the insulin-resistant state and identified F6P as a new potential regulator for ChREBP.

The promising roles of medicinal plants and bioactive compounds on hepatic lipid metabolism in the treatment of non-alcoholic fatty liver disease in animal models: molecular targets

Imbalance in hepatic lipid metabolism can lead to an abnormal triglycerides deposition in the hepatocytes which can cause non-alcoholic fatty liver disease (NAFLD). Four main mechanisms responsible for regulating hepatic lipid metabolism are fatty acid uptake, de novo lipogenesis, lipolysis and fatty acid oxidation. Controlling the expression of transcription factors at molecular level plays a crucial role in NAFLD management. This paper reviews various medicinal plants and their bioactive compounds emphasising mechanisms involved in hepatic lipid metabolism, other important NAFLD pathological features, and their promising roles in managing NAFLD through regulating key transcription factors. Although there are many medicinal plants popularly investigated for NAFLD treatment, there is still little information and scientific evidence available and there has been no research on clinical trials scrutinised on this matter. This review also aims to provide molecular information of medicinal plants in NALFD treatment that might have potentials for future scientifically controlled studies.

Metabolic dysfunction-associated fatty liver disease (MAFLD): an update of the recent advances in pharmacological treatment

Metabolic dysfunction-associated fatty liver disease (MAFLD) is nowadays considered the liver manifestation of metabolic syndrome. Its prevalence is increasing worldwide in parallel to the epidemic of diabetes and obesity. MAFLD includes a wide spectrum of liver injury including simple steatosis and non-alcoholic steatohepatitis (NASH) that may lead to serious complications such as liver cirrhosis and liver cancer. The complexity of its pathophysiology and the intricate mechanisms underlying disease progression explains the huge variety of molecules targeting diverse biological mechanisms that have been tested in preclinical and clinical settings in the last two decades. Thanks to the large number of clinical trials of the last few years, most of them still ongoing, the pharmacotherapy scenario of MAFLD is rapidly evolving. The three major components of MAFLD, steatosis, inflammation, and fibrosis seem to be safely targeted with different agents at least in a large proportion of patients. Likely, in the next few years more than one drug will be approved for the treatment of MAFLD at different disease stages. The aim of this review is to synthesize the characteristics and the results of the most advanced clinical trials for the treatment of NASH to evaluate the recent advances of pharmacotherapy in this disease.

Histone Modifications in NAFLD: Mechanisms and Potential Therapy

Nonalcoholic fatty liver disease (NAFLD) is a progressive condition that encompasses a spectrum of liver disorders, beginning with the simple steatosis, progressing to nonalcoholic steatohepatitis (NASH), and possibly leading to more severe diseases, including liver cirrhosis and hepatocellular carcinoma (HCC). In recent years, the prevalence of NAFLD has increased due to a shift towards energy-dense dietary patterns and a sedentary lifestyle. NAFLD is also strongly associated with metabolic disorders such as obesity and hyperlipidemia. The progression of NAFLD could be influenced by a variety of factors, such as diet, genetic factors, and even epigenetic factors. In contrast to genetic factors, epigenetic factors, including histone modifications, exhibit dynamic and reversible features. Therefore, the epigenetic regulation of the initiation and progression of NAFLD is one of the directions under intensive investigation in terms of pathogenic mechanisms and possible therapeutic interventions. This review aims to discuss the possible mechanisms and the crucial role of histone modifications in the framework of epigenetic regulation in NAFLD, which may provide potential therapeutic targets and a scientific basis for the treatment of NAFLD.

Characterization of feed efficiency-related key signatures molecular in different cattle breeds

Feed efficiency is a major constraint in the beef industry and has a significant negative correlation with residual feed intake (RFI). RFI is widely used as a measure of feed efficiency in beef cattle and is independent of economic traits such as body weight and average daily gain. However, key traits with commonality or specificity among beef cattle breeds at the same level of RFI have not been reported. Accordingly, the present study hypothesized that signatures associated with feed efficiency would have commonality or specificity in the liver of cattle breeds at the same RFI level. By comparing and integrating liver transcriptome data, we investigated the critical signatures closely associated with RFI in beef cattle using weighted co-expression network analysis, consensus module analysis, functional enrichment analysis and protein network interaction analysis. The results showed that the consensus modules in Angus and Charolais cattle were negatively correlated, and four (turquoise, red, tan, yellow) were significantly positively correlated in Angus liver, while (turquoise, red) were significantly negatively correlated in Charolais liver. These consensus modules were found to be primarily involved in biological processes such as substance metabolism, energy metabolism and gene transcription, which may be one of the possible explanations for the difference in feed efficiency between the two beef breeds. This research also identified five key candidate genes, PLA2G12B, LCAT, MTTP, LCAT, ABCA1 and FADS1, which are closely associated with hepatic lipid metabolism. The present study has identified some modules, genes and pathways that may be the major contributors to the variation in feed efficiency among different cattle breeds, providing a new perspective on the molecular mechanisms of feed efficiency in beef cattle and a research basis for investigating molecular markers associated with feed efficiency in beef cattle.

BATF relieves hepatic steatosis by inhibiting PD1 and promoting energy metabolism

The rising prevalence of nonalcoholic fatty liver disease (NAFLD) has become a global health threat that needs to be addressed urgently. Basic leucine zipper ATF-like transcription factor (BATF) is commonly thought to be involved in immunity, but its effect on lipid metabolism is not clear. Here, we investigated the function of BATF in hepatic lipid metabolism. BATF alleviated high-fat diet (HFD)-induced hepatic steatosis and inhibited elevated programmed cell death protein (PD)1 expression induced by HFD. A mechanistic study confirmed that BATF regulated fat accumulation by inhibiting PD1 expression and promoting energy metabolism. PD1 antibodies alleviated hepatic lipid deposition. In conclusion, we identified the regulatory role of BATF in hepatic lipid metabolism and that PD1 is a target for alleviation of NAFLD. This study provides new insights into the relationship between BATF, PD1, and NAFLD.

Hepatic FASN deficiency differentially affects nonalcoholic fatty liver disease and diabetes in mouse obesity models

Nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes are interacting comorbidities of obesity, and increased hepatic de novo lipogenesis (DNL), driven by hyperinsulinemia and carbohydrate overload, contributes to their pathogenesis. Fatty acid synthase (FASN), a key enzyme of hepatic DNL, is upregulated in association with insulin resistance. However, the therapeutic potential of targeting FASN in hepatocytes for obesity-associated metabolic diseases is unknown. Here, we show that hepatic FASN deficiency differentially affects NAFLD and diabetes depending on the etiology of obesity. Hepatocyte-specific ablation of FASN ameliorated NAFLD and diabetes in melanocortin 4 receptor-deficient mice but not in mice with diet-induced obesity. In leptin-deficient mice, FASN ablation alleviated hepatic steatosis and improved glucose tolerance but exacerbated fed hyperglycemia and liver dysfunction. The beneficial effects of hepatic FASN deficiency on NAFLD and glucose metabolism were associated with suppression of DNL and attenuation of gluconeogenesis and fatty acid oxidation, respectively. The exacerbation of fed hyperglycemia by FASN ablation in leptin-deficient mice appeared attributable to impairment of hepatic glucose uptake triggered by glycogen accumulation and citrate-mediated inhibition of glycolysis. Further investigation of the therapeutic potential of hepatic FASN inhibition for NAFLD and diabetes in humans should thus consider the etiology of obesity.

BMI change during childhood, DNA methylation change at TXNIP, and glucose change during midlife

OBJECTIVE

This study investigated whether changes in DNA methylation (DNAm) at TXNIP are associated with glycemic changes and whether such an association differs with early-life adiposity changes.

METHODS

A total of 594 Bogalusa Heart Study participants who had blood DNAm measurements at two time points in midlife were included. Of them, 353 participants had at least four BMI measurements during childhood and adolescence. The incremental area under the curve was calculated as a measure of long-term trends of BMI during childhood and adolescence.

RESULTS

Increase in DNAm at TXNIP was significantly associated with decrease in fasting plasma glucose (FPG) independent of covariates (p < 0.001). The study found that the strength of this relationship was significantly modified by a trend of increasing BMI during childhood and adolescence (p-interaction = 0.003). Each 1% increase in DNAm at TXNIP was associated with a 2.90- (0.77) mg/dL decrease in FPG among participants with the highest tertile of BMI incremental area under the curve and a 0.96- (0.38) mg/dL decrease among those with the middle tertile, whereas no association was observed among participants with the lowest tertile.

CONCLUSIONS

These results indicate that changes in blood DNAm at TXNIP are significantly associated with changes in FPG in midlife, and this association was modified by BMI trends during childhood and adolescence.

Sequential Activations of ChREBP and SREBP1 Signals Regulate the High-Carbohydrate Diet-Induced Hepatic Lipid Deposition in Gibel Carp (Carassius gibelio)

The present study investigated the sequential regulation signals of high-carbohydrate diet (HCD)-induced hepatic lipid deposition in gibel carp (Carassius gibelio). Two isonitrogenous and isolipidic diets, containing 25% (normal carbohydrate diet, NCD) and 45% (HCD) corn starch, were formulated to feed gibel carp (14.82 ± 0.04 g) for 8 weeks. The experimental fish were sampled at 2^nd, 4^th, 6^th, and 8^th week. In HCD group, the hyperlipidemia and significant hepatic lipid deposition (oil red O area and triglyceride content) was found at 4^th, 6^th, and 8^th week, while the significant hyperglycemia was found at 2^nd, 4^th, and 8^th week, compared to NCD group (P < 0.05). HCD induced hepatic lipid deposition via increased hepatic lipogenesis (acc, fasn, and acly) but not decreased hepatic lipolysis (hsl and cpt1a). When compared with NCD group, HCD significantly elevated the hepatic sterol regulatory element binding proteins 1 (SREBP1) signals (positive hepatocytes and fluorescence intensity) at 4^th, 6^th, and 8^th week (P < 0.05). The hepatic SREBP1 signals increased from 2^nd to 6^th week, but decreased at 8^th week due to substantiated insulin resistance (plasma insulin levels, plasma glucose levels, and P-AKT^Ser473 levels) in HCD group. Importantly, the hepatic carbohydrate response element binding protein (ChREBP) signals (positive hepatocytes, fluorescence intensity, and expression levels) were all significantly elevated by HCD-induced glucose-6-phosphate (G6P) accumulation at 2^nd, 4^th, 6^th, and 8^th week (P < 0.05). Compared to 2^nd and 4^th week, the hepatic ChREBP signals and G6P contents was significantly increased by HCD at 6^th and 8^th week (P < 0.05). The HCD-induced G6P accumulation was caused by the significantly increased expression of hepatic gck, pklr, and glut2 (P < 0.05) but not 6pfk at 4^th, 6^th, and 8^th week, compared to NCD group. These results suggested that the HCD-induced hepatic lipid deposition was mainly promoted by SREBP1 in earlier stage and by ChREBP in later stage for gibel carp. This study revealed the sequential regulation pathways of the conversion from feed carbohydrate to body lipid in fish.

Roles of protein post-translational modifications in glucose and lipid metabolism: mechanisms and perspectives

The metabolism of glucose and lipids is essential for energy production in the body, and dysregulation of the metabolic pathways of these molecules is implicated in various acute and chronic diseases, such as type 2 diabetes, Alzheimer's disease, atherosclerosis (AS), obesity, tumor, and sepsis. Post-translational modifications (PTMs) of proteins, which involve the addition or removal of covalent functional groups, play a crucial role in regulating protein structure, localization function, and activity. Common PTMs include phosphorylation, acetylation, ubiquitination, methylation, and glycosylation. Emerging evidence indicates that PTMs are significant in modulating glucose and lipid metabolism by modifying key enzymes or proteins. In this review, we summarize the current understanding of the role and regulatory mechanisms of PTMs in glucose and lipid metabolism, with a focus on their involvement in disease progression associated with aberrant metabolism. Furthermore, we discuss the future prospects of PTMs, highlighting their potential for gaining deeper insights into glucose and lipid metabolism and related diseases.

Dysregulation of Lipid and Glucose Metabolism in Nonalcoholic Fatty Liver Disease

Non-Alcoholic Fatty Liver Disease (NAFLD) is a highly prevalent condition affecting approximately a quarter of the global population. It is associated with increased morbidity, mortality, economic burden, and healthcare costs. The disease is characterized by the accumulation of lipids in the liver, known as steatosis, which can progress to more severe stages such as steatohepatitis, fibrosis, cirrhosis, and even hepatocellular carcinoma (HCC). This review focuses on the mechanisms that contribute to the development of diet-induced steatosis in an insulin-resistant liver. Specifically, it discusses the existing literature on carbon flux through glycolysis, ketogenesis, TCA (Tricarboxylic Acid Cycle), and fatty acid synthesis pathways in NAFLD, as well as the altered canonical insulin signaling and genetic predispositions that lead to the accumulation of diet-induced hepatic fat. Finally, the review discusses the current therapeutic efforts that aim to ameliorate various pathologies associated with NAFLD.

Phenolipid JE improves metabolic profile and inhibits gluconeogenesis via modulating AKT-mediated insulin signaling in STZ-induced diabetic mice

Phenolipids are characteristic phytochemicals of Syzygium genus. However, the antidiabetic potential and underlying molecular mechanism of these components are not fully elucidated. Herein, we studied the anti-diabetic effects of jambone E (JE), a phenolipid from S. cumini, with in vitro and in vivo models. Data from current study showed that JE enhanced glucose consumption and uptake, promoted glycogen synthesis, and suppressed gluconeogenesis in insulin resistant (IR)-HepG2 cells and primary mouse hepatocytes. JE also attenuated streptozotocin-induced hyperglycemia and hyperlipidemia in type 1 diabetic (T1D) mice. Eleven metabolites (e.g. trimethylamine n-oxide, 4-pyridoxic acid, phosphatidylinositol 39:4, phenaceturic acid, and hippuric acid) were identified as potential serum biomarkers for JE's antidiabetic effects by an untargeted metabolomics approach. The further molecular mechanistic study revealed that JE up-regulated phosphorylation levels of protein kinase B (AKT), glycogen synthase kinase 3 beta, and forkhead box O1 (FoxO1), promoted nuclear exclusion of FoxO1 whilst decreased gene expression levels of peroxisome proliferator-activated receptor gamma coactivator-1 alpha, phosphoenolpyruvate carboxykinase and glucose 6-phosphatase in IR-HepG2 cells and T1D mice. Our data suggested that JE might be a potent activator for AKT-mediated insulin signaling pathway, which was confirmed by the usage of AKT inhibitor and AKT-target siRNA interference, as well as the cellular thermal shift assay. Findings from the current study shed light on the anti-diabetic effects of phenolipids in the Syzygium species, which supports the use of medicinal plants in the Syzygium genus for potential pharmaceutical applications.

Multi-transcriptomics reveals RLMF axis-mediated signaling molecules associated with bovine feed efficiency

The regulatory axis plays a vital role in interpreting the information exchange and interactions among mammal organs. In this study on feed efficiency, it was hypothesized that a rumen-liver-muscle-fat (RLMF) regulatory axis exists and scrutinized the flow of energy along the RLMF axis employing consensus network analysis from a spatial transcriptomic standpoint. Based on enrichment analysis and protein-protein interaction analysis of the consensus network and tissue-specific genes, it was discovered that carbohydrate metabolism, energy metabolism, immune and inflammatory responses were likely to be the biological processes that contribute most to feed efficiency variation on the RLMF regulatory axis. In addition, clusters of genes related to the electron respiratory chain, including ND (2,3,4,4L,5,6), NDUF (A13, A7, S6, B3, B6), COX (1,3), CYTB, UQCR11, ATP (6,8), clusters of genes related to fatty acid metabolism including APO (A1, A2, A4, B, C3), ALB, FG (A, G), as well as clusters of the ribosomal-related gene including RPL (8,18A,18,15,13, P1), the RPS (23,27A,3A,4X), and the PSM (A1-A7, B6, C1, C3, D2-D4, D8 D9, E1) could be the primary effector genes responsible for feed efficiency variation. The findings demonstrate that high feed efficiency cattle, through the synergistic action of the regulatory axis RLMF, may improve the efficiency of biological processes (carbohydrate metabolism, protein ubiquitination, and energy metabolism). Meanwhile, high feed efficiency cattle might enhance the ability to respond to immunity and inflammation, allowing nutrients to be efficiently distributed across these organs associated with digestion and absorption, energy-producing, and energy-storing organs. Elucidating the distribution of nutrients on the RLMF regulatory axis could facilitate an understanding of feed efficiency variation and achieve the study on its molecular regulation.

Helminth infection and helminth-derived products: A novel therapeutic option for non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is closely related to obesity, diabetes, and metabolic syndrome (MetS), and it has become the most common chronic liver disease. Helminths have co-evolved with humans, inducing multiple immunomodulatory mechanisms to modulate the host's immune system. By using their immunomodulatory ability, helminths and their products exhibit protection against various autoimmune and inflammatory diseases, including obesity, diabetes, and MetS, which are closely associated with NAFLD. Here, we review the pathogenesis of NAFLD from abnormal glycolipid metabolism, inflammation, and gut dysbiosis. Correspondingly, helminths and their products can treat or relieve these NAFLD-related diseases, including obesity, diabetes, and MetS, by promoting glycolipid metabolism homeostasis, regulating inflammation, and restoring the balance of gut microbiota. Considering that a large number of clinical trials have been carried out on helminths and their products for the treatment of inflammatory diseases with promising results, the treatment of NAFLD and obesity-related diseases by helminths is also a novel direction and strategy.

Transcriptional regulation of Acsl1 by CHREBP and NF-kappa B in macrophages during hyperglycemia and inflammation

Acyl-CoA synthetase 1 (ACSL1) is an enzyme that converts fatty acids to acyl-CoA-derivatives for lipid catabolism and lipid synthesis in general and can provide substrates for the production of mediators of inflammation in monocytes and macrophages. Acsl1 expression is increased by hyperglycemia and inflammatory stimuli in monocytes and macrophages, and promotes the pro-atherosclerotic effects of diabetes in mice. Yet, surprisingly little is known about the mechanisms underlying Acsl1 transcriptional regulation. Here we demonstrate that the glucose-sensing transcription factor, Carbohydrate Response Element Binding Protein (CHREBP), is a regulator of the expression of Acsl1 mRNA by high glucose in mouse bone marrow-derived macrophages (BMDMs). In addition, we show that inflammatory stimulation of BMDMs with lipopolysaccharide (LPS) increases Acsl1 mRNA via the transcription factor, NF-kappa B. LPS treatment also increases ACSL1 protein abundance and localization to membranes where it can exert its activity. Using an Acsl1 reporter gene containing the promoter and an upstream regulatory region, which has multiple conserved CHREBP and NF-kappa B (p65/RELA) binding sites, we found increased Acsl1 promoter activity upon CHREBP and p65/RELA expression. We also show that CHREBP and p65/RELA occupy the Acsl1 promoter in BMDMs. In primary human monocytes cultured in high glucose versus normal glucose, ACSL1 mRNA expression was elevated by high glucose and further enhanced by LPS treatment. Our findings demonstrate that CHREBP and NF-kappa B control Acsl1 expression under hyperglycemic and inflammatory conditions.

An Epigenetic Role of Mitochondria in Cancer

Mitochondria are not only the main energy supplier but are also the cell metabolic center regulating multiple key metaborates that play pivotal roles in epigenetics regulation. These metabolites include acetyl-CoA, α-ketoglutarate (α-KG), S-adenosyl methionine (SAM), NAD⁺, and O-linked beta-N-acetylglucosamine (O-GlcNAc), which are the main substrates for DNA methylation and histone post-translation modifications, essential for gene transcriptional regulation and cell fate determination. Tumorigenesis is attributed to many factors, including gene mutations and tumor microenvironment. Mitochondria and epigenetics play essential roles in tumor initiation, evolution, metastasis, and recurrence. Targeting mitochondrial metabolism and epigenetics are promising therapeutic strategies for tumor treatment. In this review, we summarize the roles of mitochondria in key metabolites required for epigenetics modification and in cell fate regulation and discuss the current strategy in cancer therapies via targeting epigenetic modifiers and related enzymes in metabolic regulation. This review is an important contribution to the understanding of the current metabolic-epigenetic-tumorigenesis concept.

Hematological Changes in Sika Doe and Suckling Fawn Fed with Spent Mushroom Substrate of Pleurotus ostreatus

Sika deer velvet antler is the most important animal nutraceutic in traditional Chinese medicine. Reducing the breeding cost of sika deer by looking for a low-cost diet is the main research direction at present. The purpose of this experiment was to find an alternative diet for sika deer and reduce the cost of the diet by using spent mushroom substrate (SMS) as a concentrate supplement. The apparent digestibility for sika doe and the hematological changes of sika doe and suckling fawn were measured by replacing 10% of the concentrate supplement with SMS of Pleurotus ostreatus (SMS-MP). Compared with the control group, the digestibility of dry matter (DM), total protein (TP), globulin (GLO), and cholesterol (CHOL) of sika doe were significantly decreased (p < 0.05), and glucose (GLU), alanine (Ala), phenylalanine (Phe), and proline (Pro) of sika doe were significantly increased (p < 0.05) after the replacement of SMS-MP. Compared with the control group, the serum GLU of suckling fawn was significantly decreased (p < 0.05) and the phosphatase (ALP) was significantly increased after the replacement of SMS-MP (p < 0.05). There were no significant differences in the immune globulin and amino acid of suckling fawns between the two groups (p > 0.05). The present findings confirm the applicability of SMS-MP as a sika doe concentrate supplement. At the same time, using SMS, a waste resource, can not only reduce the breeding cost of sika doe, but also make full use of SMS to reduce environmental pollution.

Sex-dependent effect of triphenyl phosphate on hepatic energy metabolism at the intersection of diet pattern in pubertal mice

Triphenyl phosphate (TPhP) is mostly residual in fat-rich foodstuff and ingestion is the main route for adolescents' exposure. As a typical metabolic disruptor, however, sex-specific effect of TPhP-high fat diet (HFD) co-exposure in adolescent remains unknown. This study revealed that HFD exacerbated systematic inflammation and insulin insensitivity in female mice at pubertal stage after exposure to 25 mg/kg TPhP or above. Notably, the pattern of sexual selective metabolic disruption caused by TPhP was irrespective of diet after examined mice both in HFD and normal diet feeding. Female mice favored the energy storage in forms of D-glucose 6-phosphate, D-fructose 6-phosphate and triglyceride. That was further supported by mRNA levels of key enzymes in glycolysis, gluconeogenesis, and lipid metabolism. Contrastingly, the elevation of the corresponding genes ensuing by the depleted metabolites were observed in males. In mechanistic investigation, we observed a declination of serum estrogen, a master of energy homeostasis, in both sexes, irrespective of diet. However, only male mice displayed estrogen-hypothalamus negative feedback, supporting by the upregulation of gonadotropin-releasing hormone. Rather than the well-recognized estrogen receptor α, hepatic G protein-coupled estrogen receptor manifested sexual dichotomy, which desensitized to estrogenic response only in females. Collectively, this study posited that females were more susceptible to store energy under TPhP-HFD than males during pubertal partially through estrogenic pathway.

Velvet Antler Production and Hematological Changes in Male Sika Deers Fed with Spent Mushroom Substrate

At present, spent mushroom substrate (SMS) is a waste resource that is producing a pollution problem in China, and which has some use as animal feed or fertilizer, has not been assessed as a feed for deer. The purpose of this study is to expand the feed of male sika deer and reduce the feeding cost by using the waste resource of SMS. The 10% concentrated supplement was replaced with SMS and the feed intake, apparent digestibility, blood index and velvet production of male sika deer were measured. As the results showed, compared to the control group, the substitution of SMS for 10% of the concentrate supplement decreased the concentration of IgA (p < 0.01), replacing 10% concentrated supplement with SMS of Pleurotus ostreatus (SMS-MP) reduced the intake of organic matter (OMI) and improved the digestibility of ether extract (EE), while replacing 10% concentrated supplement with SMS of Flammulina velutipes (SMS-MF) had no effect on apparent nutrient digestibility, feed intake, velvet antler production, and biochemical indexes. In conclusion, SMS had no effect on serum biochemical indexes and the ratio of the feed weight of the deer supplement to the weight of velvet antler (p > 0.05). At the same time, SMS could reduce the feed consumption and improve the economy by using SMS as a waste resource.

ANGPTL3 Is Involved in the Post-prandial Response in Triglyceride-Rich Lipoproteins and HDL Components in Patients With Coronary Artery Disease

It is well-established that there exists an inverse relationship between high-density lipoprotein (HDL) cholesterol and triglyceride (TG) levels in the plasma. However, information is lacking on the impact of post-prandial triglyceride-rich lipoproteins (TRLs) on the structure of HDL subclasses in patients with coronary artery disease (CAD). In this study, the data of 49 patients with CAD were analyzed to evaluate dynamic alterations in post-prandial lipid profiles using nuclear magnetic resonance-based methods. An enzyme-linked immunosorbent assay was used to quantify the serum angiopoietin-like protein 3 (ANGPTL3). After glucose supplementation, the expression of hepatic ANGPTL3 was evaluated both in vitro and in vivo. Compared to fasting levels, the post-prandial serum TG level of all participants was considerably increased. Although post-prandial total cholesterol in HDL (HDL-C) remained unchanged, free cholesterol in HDL particles (HDL-FC) was significantly reduced after a meal. Furthermore, the post-prandial decrease in the HDL-FC level corresponded to the increase in remnant cholesterol (RC), indicating the possible exchange of free cholesterol between HDL and TRLs after a meal. Moreover, CAD patients with exaggerated TG response to diet, defined as TG increase >30%, tend to have a greater post-prandial increase of RC and decrease of HDL-FC compared to those with TG increase ≤30%. Mechanistically, the fasting and post-prandial serum ANGPTL3 levels were significantly lower in those with TG increase ≤30% than those with TG increase >30%, suggesting that ANGPTL3, the key lipolysis regulator, may be responsible for the different post-prandial responses of TG, RC, and HDL-FC.

Maternal Pyrroloquinoline Quinone Supplementation Improves Offspring Liver Bioactive Lipid Profiles throughout the Lifespan and Protects against the Development of Adult NAFLD

Maternal obesity and consumption of a high-fat diet significantly elevate risk for pediatric nonalcoholic fatty liver disease (NAFLD), affecting 10% of children in the US. Almost half of these children are diagnosed with nonalcoholic steatohepatitis (NASH), a leading etiology for liver transplant. Animal models show that signs of liver injury and perturbed lipid metabolism associated with NAFLD begin in utero; however, safe dietary therapeutics to blunt developmental programming of NAFLD are unavailable. Using a mouse model of maternal Western-style diet (WD), we previously showed that pyrroloquinoline quinone (PQQ), a potent dietary antioxidant, protected offspring of WD-fed dams from development of NAFLD and NASH. Here, we used untargeted mass spectrometry-based lipidomics to delineate lipotoxic effects of WD on offspring liver and identify lipid targets of PQQ. PQQ exposure during pregnancy altered hepatic lipid profiles of WD-exposed offspring, upregulating peroxisome proliferator-activated receptor (PPAR) α signaling and mitochondrial fatty acid oxidation to markedly attenuate triglyceride accumulation beginning in utero. Surprisingly, the abundance of very long-chain ceramides, important in promoting gut barrier and hepatic function, was significantly elevated in PQQ-treated offspring. PQQ exposure reduced the hepatic phosphatidylcholine/phosphatidylethanolamine (PC/PE) ratio in WD-fed offspring and improved glucose tolerance. Notably, levels of protective n - 3 polyunsaturated fatty acids (PUFAs) were elevated in offspring exposed to PQQ, beginning in utero, and the increase in n - 3 PUFAs persisted into adulthood. Our findings suggest that PQQ supplementation during gestation and lactation augments pathways involved in the biosynthesis of long-chain fatty acids and plays a unique role in modifying specific bioactive lipid species critical for protection against NAFLD risk in later life.

Chronic inflammatory arthritis drives systemic changes in circadian energy metabolism

Chronic inflammation underpins many human diseases. Morbidity and mortality associated with chronic inflammation are often mediated through metabolic dysfunction. Inflammatory and metabolic processes vary through circadian time, suggesting an important temporal crosstalk between these systems. Using an established mouse model of rheumatoid arthritis, we show that chronic inflammatory arthritis results in rhythmic joint inflammation and drives major changes in muscle and liver energy metabolism and rhythmic gene expression. Transcriptional and phosphoproteomic analyses revealed alterations in lipid metabolism and mitochondrial function associated with increased EGFR-JAK-STAT3 signaling. Metabolomic analyses confirmed rhythmic metabolic rewiring with impaired β-oxidation and lipid handling and revealed a pronounced shunt toward sphingolipid and ceramide accumulation. The arthritis-related production of ceramides was most pronounced during the day, which is the time of peak inflammation and increased reliance on fatty acid oxidation. Thus, our data demonstrate that localized joint inflammation drives a time-of-day–dependent build-up of bioactive lipid species driven by rhythmic inflammation and altered EGFR-STAT signaling.

Fructose Intake, Hypertension and Cardiometabolic Risk Factors in Children and Adolescents: From Pathophysiology to Clinical Aspects. A Narrative Review

Arterial hypertension, dyslipidemia, alterations in glucose metabolism and fatty liver, either alone or in association, are frequently observed in obese children and may seriously jeopardize their health. For obesity to develop, an excessive intake of energy-bearing macronutrients is required; however, ample evidence suggests that fructose may promote the development of obesity and/or metabolic alterations, independently of its energy intake. Fructose consumption is particularly high among children, because they do not have the perception, and more importantly, neither do their parents, that high fructose intake is potentially dangerous. In fact, while this sugar is erroneously viewed favorably as a natural nutrient, its excessive intake can actually cause adverse cardio-metabolic alterations. Fructose induces the release of pro-inflammatory cytokines, and reduces the production of anti-atherosclerotic cytokines, such as adiponectin. Furthermore, by interacting with hunger and satiety control systems, particularly by inducing leptin resistance, it leads to increased caloric intake. Fructose, directly or through its metabolites, promotes the development of obesity, arterial hypertension, dyslipidemia, glucose intolerance and fatty liver. This review aims to highlight the mechanisms by which the early and excessive consumption of fructose may contribute to the development of a variety of cardiometabolic risk factors in children, thus representing a potential danger to their health. It will also describe the main clinical trials performed in children and adolescents that have evaluated the clinical effects of excessive intake of fructose-containing drinks and food, with particular attention to the effects on blood pressure. Finally, we will discuss the effectiveness of measures that can be taken to reduce the intake of this sugar.

Insulin Resistance: From Mechanisms to Therapeutic Strategies

Insulin resistance is the pivotal pathogenic component of many metabolic diseases, including type 2 diabetes mellitus, and is defined as a state of reduced responsiveness of insulin-targeting tissues to physiological levels of insulin. Although the underlying mechanism of insulin resistance is not fully understood, several credible theories have been proposed. In this review, we summarize the functions of insulin in glucose metabolism in typical metabolic tissues and describe the mechanisms proposed to underlie insulin resistance, that is, ectopic lipid accumulation in liver and skeletal muscle, endoplasmic reticulum stress, and inflammation. In addition, we suggest potential therapeutic strategies for addressing insulin resistance.

Phospholipase C signal mediated the glucose-induced changes of glucose absorption and lipid accumulation in the intestinal epithelial cells of yellow catfish Pelteobagrus fulvidraco

In present study, we explored the effects and the underlying mechanisms of phospholipase C (PLC) mediating glucose-induced changes in intestinal glucose transport and lipid metabolism by using U-73122 (a PLC inhibitor). We found that glucose incubation activated the PLC signal and U-73122 pre-incubation alleviated the glucose-induced increase in plcb2, plce1 and plcg1 mRNA expression. Meanwhile, U-73122 pre-treatment blunted the glucose-induced increase in sodium/glucose co-transporters 1/2 mRNA and protein expressions. U-73122 pre-treatment alleviated the glucose-induced increase in TAG content, BODIPY 493/503 fluorescence intensity, lipogenic enzymes (glucose 6-phospate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), malic enzyme and fatty acid synthase (FAS)) activity and the mRNA expressions of lipogenic genes and related transcription factors (6pgd, g6pd, fas, acca, srebp1 and carbohydrate response element-binding protein (chrebp)) in intestinal epithelial cells of yellow catfish. Further research found that U-73122 pre-incubation mitigated the glucose-induced increase in the ChREBP protein expression and the acetylation level of ChREBP in HEK293T cells. Taken together, these data demonstrated that the PLC played a major role in the glucose-induced changes of glucose transport and lipid metabolism and provide a new perspective for revealing the molecular mechanism of glucose-induced changes of intestinal glucose absorption, lipid deposition and metabolism.