The study aimed to investigate the role of carbohydrate-responsive element-binding protein (ChREBP) in the pathogenesis of pulmonary fibrosis (PF) by assessing its impact on fibrotic protein expression, fibroblast proliferation, and apoptosis in lung tissues.

The PF model was established using bleomycin, and pathological changes in lung tissues were assessed through histopathological analysis. Expression levels of inflammatory markers and fibrotic proteins, including ChREBP, were measured using Western blot and ELISA. Additionally, human embryonic lung fibroblasts (MRC-5) were transfected with ChREBP overexpression or silencing vectors following TGF-β1 induction to examine changes in cellular behavior, including viability, apoptosis, and fibrotic protein expression.

The PF model group showed significant alveolar structural abnormalities and elevated levels of TNF-α, MMP-7 and TGF-β1. ChREBP expression was markedly increased in fibrotic tissues (P < 0.05). In vitro, ChREBP overexpression in MRC-5 cells enhanced fibrotic protein levels, increased cell viability, and reduced apoptosis rates. Conversely, silencing ChREBP reduced fibrotic protein expression, inhibited fibroblast proliferation, and increased apoptosis (P < 0.05). These findings suggest that ChREBP plays a key role in modulating fibrosis-related pathways in PF.

ChREBP is substantially upregulated in PF and plays a key role in promoting fibroblast proliferation and inhibiting apoptosis. These findings suggest that targeting ChREBP may present a novel therapeutic strategy for treating pulmonary fibrosis by modulating fibrotic and apoptotic pathways.

Carbohydrate response element-binding protein (ChREBP) is a transcription factor activated by glucose metabolites that orchestrates the expression of genes involved in glycolysis, de novo lipogenesis, and ATP homeostasis. Inadequate ChREBP activity impairs the cellular adaptations to glucose exposure and in humans associates with dyslipidemia, fatty liver disease, and type 2 diabetes. ChREBP activity is regulated by cytosolic-nuclear translocation involving its low-glucose inhibitory domain (LID). Whether this domain is targeted by post-translational lysine acetylation is unknown. Here we report a novel LID acetylation site that controls activity and protein interactions of ChREBP. Mutation of this residue increased glucose-induced activity and target gene expression of ChREBP. Mechanistically, mutant ChREBP protein showed more nuclear localization and enhanced genomic binding to a target promoter. Interactions with proteins that exhibit differential binding upon glucose exposure were attenuated by the mutation, demonstrating the importance of the LID in the formation of the protein interactome. Particularly interactions with 14-3-3 proteins, factors that regulate cytosolic/nuclear trafficking of ChREBP, were reduced, whereas interactions with proteins of the nucleosome remodeling deacetylase complex (NuRD) were increased. These molecular insights may shape new therapeutic strategies to target ChREBP activity and counteract metabolic diseases.

Fructose, a common sweetener in modern diets, has profound effects on both metabolism and brain function, primarily due to its distinct metabolic pathways. Unlike glucose, fructose bypasses critical regulatory steps in metabolism, particularly the phosphofructokinase-1 (PFK-1) feedback inhibition, leading to uncontrolled metabolism and increased fat storage. This review delves into the metabolic consequences of fructose consumption, including its limited role in directly stimulating insulin secretion, which affects satiety signaling and contributes to increased food intake. The small intestine initially helps metabolize ingested fructose, shielding the liver and brain from excessive exposure. However, when consumed in excess, particularly in diets high in processed foods, this protective mechanism becomes overwhelmed, contributing to metabolic disorders such as insulin resistance, obesity, and fatty liver disease. The review also explores fructose's impact on the brain, with a focus on the hippocampus, a key region for memory and learning. Chronic high fructose intake has been linked to mitochondrial dysfunction, increased production of reactive oxygen species (ROS), and neuroinflammation, all of which contribute to cognitive decline and impairments in memory and learning. Additionally, fructose-induced alterations in insulin signaling in the brain are associated with increased risk for neurodegenerative diseases. These findings underscore the potential long-term neurological consequences of excessive fructose intake and highlight the need for further human studies to assess the full spectrum of its effects on brain health. Addressing the rising consumption of fructose, particularly in processed foods, is essential for developing targeted strategies to mitigate its adverse metabolic and cognitive outcomes.

The deficiency of fructose-1,6-bisphosphatase 1 (FBP1), a key enzyme of gluconeogenesis, causes fatty liver. However, its underlying mechanism and physiological significance are not fully understood. Here we demonstrate that carbohydrate response element-binding protein (ChREBP) mediates lipid metabolic remodeling and promotes progressive triglyceride accumulation against metabolic injury in adult FBP1-deficient liver. Inducible liver-specific deletion of Fbp1 gene caused progressive hepatomegaly and hepatic steatosis, with a marked increase in hepatic de novo lipogenesis (DNL) as well as a decrease in plasma β-hydroxybutyrate levels. Notably, FBP1 deficiency resulted in a persistent activation of ChREBP and its target genes involved in glycolysis, lipogenesis, and fatty acid oxidation, even under fasting conditions. Furthermore, liver-specific ChREBP disruption could markedly restore the phenotypes of enhanced DNL and triglyceride accumulation in FBP1-deficient liver but exacerbated its hepatomegaly and liver injury, which was associated with remarkable energy deficit, impaired mammalian target of rapamycin (mTOR) activation, and increased oxidative stress. Furthermore, metabolomics analysis revealed a robust elevation of phosphoenolpyruvate, phosphoglycerates, phospholipids, and ceramides caused by ChREBP deletion in FBP1-deficient liver. Put together, these results suggest that overactivation of ChREBP pathway mediates liver metabolic remodeling in the absence of FBP1, which contributes to the pathogenesis of progressive hepatic steatosis and provides a protection against liver injury. Thus, our findings point to a beneficial role of ChREBP in metabolic remodeling in the context of excessive gluconeogenic intermediates.NEW & NOTEWORTHY FBP1 deficiency in adulthood causes progressive hepatic steatosis due to the overactivation of ChREBP pathway, which enhances lipid synthesis and inhibits fat oxidation. ChREBP-mediated metabolic remodeling protects against liver injury caused by energy deficit and oxidative stress in FBP1-deficient liver.

Overall adiposity and body fat distribution are heritable traits associated with altered risk of cardiometabolic disease and mortality. Performing rare variant (minor allele frequency<1%) association testing using exome-sequencing data from 402,375 participants in the UK Biobank (UKB) for nine overall and tissue-specific fat distribution traits, we identified 19 genes where putatively damaging rare variation associated with at least one trait (Bonferroni-adjusted P <1.58×10 -7 ) and 50 additional genes at FDR≤1% ( P ≤4.37×10 -5 ). These 69 genes exhibited significantly higher (one-sided t -test P =3.58×10 -18 ) common variant prioritisation scores than genes not significantly enriched for rare putatively damaging variation, with evidence of monotonic allelic series (dose-response relationships) among ultra-rare variants (minor allele count≤10) in 22 genes. Combining rare and common variation evidence, allelic series and longitudinal analysis, we selected 14 genes for CRISPR knockdown in human white adipose tissue cell lines. In three previously uncharacterised target genes, knockdown increased (two-sided t -test P <0.05) lipid accumulation, a cellular phenotype relevant for fat mass traits, compared to Cas9-empty negative controls: COL5A3 (fold change [FC]=1.72, P =0.0028), EXOC7 (FC=1.35, P =0.0096), and TRIP10 (FC=1.39, P =0.0157); furthermore, knockdown of PPARG (FC=0.25, P =5.52×10 -7 ) and SLTM (FC=0.51, P =1.91×10 -4 ) resulted in reduced lipid accumulation. Integrating across population-based genetic and in vitro functional evidence, we highlight therapeutic avenues for altering obesity and body fat distribution by modulating lipid accumulation.

The transcription factor carbohydrate response element binding protein (ChREBP) has emerged as a crucial regulator of hepatic glucose and lipid metabolism. The increased ChREBP activity involves the pro-oncogenic PI3K/AKT/mTOR signaling pathway that induces aberrant lipogenesis, thereby promoting hepatocellular carcinomas (HCC). However, the molecular pathogenesis of ChREBP-related hepatocarcinogenesis remains unexplored in the high-fat diet (HFD)-induced mouse model. Male C57BL/6J (WT) and liver-specific (L)-ChREBP-KO mice were maintained on either a HFD or a control diet for 12, 24, and 48 weeks, starting at the age of 4 weeks. At the end of the feeding period, mice were perfused, and liver tissues were formalin-fixed, paraffin-embedded, sectioned, and stained for histological and immunohistochemical analysis. Biochemical and gene expression analysis were conducted using serum and frozen liver tissue. Mice fed with HFD showed a significant increase (p < 0.05) in body weight from 8 weeks onwards compared to the control. WT and L-ChREBP-KO mice also demonstrated a significant increase (p < 0.05) in liver-to-body weight ratio in the 48-week HFD group. HFD mice exhibited a gradual rise in hepatic lipid accumulation over time, with 24-week mice showing a 20-30% increase in fat content, which further advanced to 80-100% fat accumulation at 48 weeks. Both dietary source and the increased expression of lipogenic pathways at transcriptional and protein levels induced steatosis and steatohepatitis in the HFD group. Moreover, WT mice on a HFD exhibited markedly higher inflammation compared to the L-ChREBP-KO mice. The enhanced lipogenesis, glycolysis, persistent inflammation, and activation of the AKT/mTOR pathway collectively resulted in significant metabolic disturbances, thereby promoting HCC development and progression in WT mice. In contrast, hepatic loss of ChREBP resulted in reduced hepatocyte proliferation in the HFD group, which significantly contributed to the impaired hepatocarcinogenesis and a reduced HCC occurrence in the L-ChREBP-KO mice. Our present study implicates that prolonged HFD feeding contributes to NAFLD/NASH, which in turn progresses to HCC development in WT mice. Collectively, hepatic ChREBP deletion ameliorates hepatic inflammation and metabolic alterations, thereby impairing NASH-driven hepatocarcinogenesis.

Many traditional treatments include honey owing to its magnificent health beneficiary effects. Recent studies have demonstrated the potent anti-diabetic activity of honey. However, its actual mechanism of action remains elusive. Moreover, being rich in sugar (75%-80%), its role in maintaining glucose homeostasis remains questionable. Although the polyphenol content of honey aids its hypoglycaemic activity, the small quantity of bioactive compounds in honey (0.5%-1.0%) may not be solely responsible for this. In the current study, an attempt was made to understand the role of Indian lychee honey (LyH) in regulating blood glucose levels under diabetic conditions. This study investigated whether LyH, although rich in sugars, can be used as an alternative to regulate glucose and lipid homeostasis under insulin-resistant conditions by regulating the ChREBP/Glut4 signalling pathway. This study was first performed in vitro in palmitic acid-induced insulin-resistant HepG2 cells. Various assays, such as FACS, GCMS, qRT-PCR, immunoblot and ChIP-qPCR, were performed to establish the anti-hyperglycaemic role of LyH in vitro. The in vitro results were subsequently confirmed in vivo using a high-fat diet-induced diabetic C57BL/6 mice model. The in vivo study was supported by several experiments, such as examining blood parameters, histopathology, double-immunohistochemistry and ELISA. Finally, the finding was validated by comparing it with a couple of GEO datasets from the NCBI database. This study found that LyH is an excellent choice for regulating blood sugar levels under diabetic conditions without significant harmful side effects. Moreover, LyH showed excellent hepatic glucose uptake activity in an insulin-independent manner. This activity is mainly governed by sugars as its main ingredient. LyH treatment also regulates hepatic lipid homeostasis by maintaining a balance between saturated and unsaturated fatty acids in insulin-resistant HepG2 cells. Further, sugar, when supplemented individually, caused severe inflammation, which was validated through histopathology, ELISA and IHC. Collectively, the findings of this study indicate that Indian LyH provides a better food matrix (the right proportion of sugars and different bioactive compounds), which significantly improves hyperglycemia and inflammation under diabetic conditions by regulating the hepatic ChREBP/Glut4 axis.

A glucose-dependent carbohydrate-signaling gene regulator named Carbohydrate response element binding protein (ChREBP), has recently been discovered as a major metabolic regulator of enzymes involved in the progression of non-alcoholic fatty liver disease (NAFLD) and type-II diabetes mellitus (T2DM). As a result, this research is aimed to identify natural small molecules as drug candidates that target the ChREBP in order to counter aggressive NAFLD and T2DM. A comprehensive in silico drug design strategy was implemented to find possible inhibitors of the targeted protein. A site-specific molecular docking approach was used to screen 20 FDA approved anti-diabetic drugs and 494 phytochemicals from the natural sources against the ChREBP, and the top ten compounds were selected for further studies based on their binding affinities. The ADME and toxicity profiles of the selected ten drug compounds demonstrated their efficacy and safety. The result of the MD simulations of the protein-ligand complex structures indicated their stability and potential activity. A comprehensive data screening process following docking, ADMET properties, and MD simulation approaches, five compounds (dieckol, isocorilagin, stachyurin, stachysetin and thonningianin A) with favorable values against the targeted ChREBP were demonstrated which indicates their strong potential as promising and effective drug candidates for the treatment of NAFLD and T2DM.

The transcription factor carbohydrate response element binding protein (ChREBP) activates genes of glucose, fructose, and lipid metabolism in response to carbohydrate feeding. Integrated transcriptomic and metabolomic analyses in rats with GalNac-siRNA-mediated suppression of ChREBP expression in liver reveal other ChREBP functions. GalNac-siChREBP treatment reduces expression of genes involved in coenzyme A (CoA) biosynthesis, with lowering of CoA and short-chain acyl-CoA levels. Despite suppression of pyruvate kinase, pyruvate levels are maintained, possibly via increased expression of pyruvate and amino acid transporters. In addition, expression of multiple anaplerotic enzymes is decreased by GalNac-siChREBP treatment, affecting TCA cycle intermediates. Finally, GalNAc-siChREBP treatment suppresses late steps in purine and NAD synthesis, with increases in precursors and lowering of end products in both pathways. In sum, our study reveals functions of ChREBP beyond its canonical roles in carbohydrate and lipid metabolism to include regulation of substrate transport, mitochondrial function, and energy balance.

Background/Objectives: Carbohydrate and protein restriction are associated with sarcopenia and osteopenia, but the underlying mechanisms remain unclear. We aimed to determine whether mild protein restriction affects muscle and bone function in wild-type (WT) and homozygous carbohydrate response element binding protein (Chrebp) knockout (KO) mice. Methods: Eighteen-week-old male wild-type and homozygous carbohydrate response element binding protein (Chrebp) knockout (KO) mice were fed a control diet (20% protein) or a low-protein diet (15% protein) for 12 weeks. We estimated the muscle weight and limb grip strength as well as the bone mineral density, bone structure, and bone morphometry. Results: Chrebp deletion and a low-protein diet additively decreased body weight (WT control-KO low-protein: mean difference with 95% CI, 8.7 [6.3, 11.0], p < 0.0001) and epidydimal fat weight (1.0 [0.7, 1.2], p < 0.0001). Chrebp deletion and a low-protein diet additively decreased tibialis anterior muscle weight (0.03 [0.01, 0.05], p = 0.002) and limb grip strength (63.9 [37.4, 90.5], p < 0.0001) due to a decrease in insulin/insulin-like growth factor 1 mRNA and an increase in myostatin mRNA. In contrast, Chrebp deletion increased bone mineral density (BMD) (WT control-KO control: -6.1 [-1.0, -2.3], p = 0.0009), stiffness (-21.4 [-38.8, -4.1], p = 0.011), cancellous bone BV/TV (-6.517 [-10.99, -2.040], p = 0.003), and the number of trabeculae (-1.1 [-1.8, -0.5], p = 0.0008). However, in KO mice, protein restriction additively decreased BMD (KO control-KO low-protein: 8.1 [4.3, 11.9], p < 0.0001), bone stiffness (38.0 [21.3, 54.7], p < 0.0001), cancellous bone BV/TV (7.7 [3.3, 12.2], p = 0.006), and the number of trabeculae (1.2 [0.6, 1.9], p = 0.0004). The effects of mild protein restriction on bone formation parameters (osteoid volume (WT control-WT low-protein: -1.7 [-2.7, -0.7], p = 0.001) and the osteoid surface (-11.2 [-20.8, -1.5], p = 0.02) were observed only in wild-type (WT) mice. The levels of bone resorption markers, such as the number of osteoclasts on the surface, the number of osteoclasts, and surface erosion, did not differ between the groups. Conclusions: Both Chrebp deletion and protein restriction led to a decrease in muscle and bone function; therefore, an adequate intake of carbohydrates and proteins is important for maintaining muscle and bone mass and function. Further studies will be needed to elucidate the mechanisms by which ChREBP deletion and a low-protein diet cause osteosarcopenia.

In addition to being linked to an excess of lipid accumulation in the liver, being overweight or obese can also result in disorders of lipid metabolism. There is limited understanding regarding whether different levels of protein intake within an energy-restricted diet affect liver lipid metabolism in overweight and obese rats and whether these effects differ by gender, despite the fact that both high protein intake and calorie restriction can improve intrahepatic lipid. The purpose of this study is to explore the effects and mechanisms of different protein intakes within a calorie-restricted diet on liver lipid metabolism, and to investigate whether these effects exhibit gender differences. The Sprague-Dawley rats, which were half female and half male, were used to construct a rat model of overweight and obesity attributed to a high-fat diet. They were then split up into five groups: the normal control (NC) group, the model control (MC) group, the calorie-restricted low protein (LP) group, the calorie-restricted normal protein (NP) group, and the calorie-restricted high protein (HP) group. Body weight was measured weekly. Samples of plasma and liver were obtained after eight weeks and analyzed for glucose, triglycerides, cholesterol, and hormones in the plasma as well as the liver fat and factors involved in the liver's synthesis and degradation. For the male rats, compared to the HP group, the weight of liver fat in the LP and NP group was significantly higher (P < 0.05). However, for the female rats, there was no significant variation among the three calorie-restricted groups (P > 0.05). There was no significant variation in the concentration of total cholesterol (TC), very low density lipoprotein (VLDL), low density lipoprotein (LDL), and high density lipoprotein (HDL) among the three male calorie-restricted groups (P > 0.05), while the TC and VLDL concentrations in the female LP and NP group were significantly higher compared to those in the HP group (P < 0.05). Moreover, the trend of expression in the signaling pathways of adiponectin/phosphorylated AMP-activated protein kinase (p-AMPK) and adiponectin/peroxisome proliferators-activated receptor alpha (PPARα) in the liver was consistent with that of the liver fat content, and leptin acted in the same way as adiponectin. Compared with the three calorie-restricted groups, the expressions of nuclear sterol-regulatory element-binding protein-2 (nSREBP-2) and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase) involved in cholesterol synthesis and low-density lipoprotein receptor (LDLR) and cholesterol 7-alpha hydroxylase (CYP7A1) involved in cholesterol clearance in the MC group were significantly lower (P < 0.05). A 40% energy restriction can significantly reduce the body weight, body fat, liver fat, and the blood concentration of TG in both male and female overweight and obese rats, but it can significantly increase the blood concentration of TC in overweight and obese male rats. At the same time of 40% calorie restriction, increasing dietary protein intake to twice the normal protein intake has a stronger effect on promoting hepatic triglyceride oxidation and reducing liver fat content in the male overweight and obese rats by increasing the levels of adiponectin and leptin in the blood, and can also significantly reduce the plasma cholesterol concentration in the female overweight and obese rats through inhibiting cholesterol synthesis most likely by increasing glucagon level in the blood.

Few studies have evaluated the impact of branched-chain amino acid (BCAA) intake on the risk of obesity in adults. The results are contradictory, and the causality has not been explored. This study assessed the association between BCAA intake and obesity incidence among Brazilian adults and investigated the potential moderating role of the plant-based index (PDI) in this relationship.

A longitudinal study was conducted between 2016 and 2022, with 3090 participants (2043 women, 1047 men; mean age 34 years) from the Cohort of Universities of Minas Gerais (CUME) Study. Data were collected through an online questionnaire. The relationship between BCAA intake and obesity incidence was assessed using crude and adjusted Cox regression models. Restricted cubic spline analysis (RCS) was used to estimate the nonlinearity. The multiplicative interaction with PDI was tested.

The overall incidence of obesity was 192 cases (6.21%). The incidence was 16.4/1000 person-years in females; 21.8/1000 person-years in males; and 18.3/1000 person-years total, with a mean follow-up period of 3.4 years. Compared to the first tertile, the highest intake tertiles for BCAA (HR = 1.50, 95% CI = 1.03-2.18), isoleucine (HR = 1.52, 95% CI = 1.04-2.22), and leucine (HR = 1.51, 95% CI = 1.03-2.20) were independently associated with obesity risk. BCAA intake above 16 g/day increases the risk of obesity.

There was a positive association between the intake of BCAA, isoleucine, and leucine with the risk of obesity. The PDI accentuated the association between BCAA intake and obesity in both the lowest and highest quintiles.

Hepatic organoid cultures are a powerful model to study liver development and diseases in vitro. However, hepatocyte-like cells differentiated from these organoids remain immature compared to primary human hepatocytes (PHHs), which are the benchmark in the field. Here, we applied integrative single-cell transcriptome and chromatin accessibility analysis to reveal gene regulatory mechanisms underlying these differences. We found that, in mature human hepatocytes, activator protein 1 (AP-1) factors co-occupy regulatory regions with hepatocyte-specific transcription factors, including HNF4A, suggesting their potential cooperation in governing hepatic gene expression. Comparative analysis identified distinct transcription factor sets that are specifically active in either PHHs or intrahepatic cholangiocyte organoid (ICO)-derived human hepatocytes. ELF3 was one of the factors uniquely expressed in ICO-derived hepatocytes, and its expression negatively correlated with hepatic marker gene expression. Functional analysis further revealed that ELF3 depletion increased the expression of key hepatic markers in ICO-derived hepatocytes. Our integrative analysis provides insights into the transcriptional regulatory networks of PHHs and hepatic organoids, thereby informing future strategies for developing improved hepatic models.

Glucose and insulin positively regulate glycolysis and lipogenesis through the activation of carbohydrate response element-binding protein (ChREBP) and sterol regulatory element-binding protein 1c (SREBP1c), but their respective roles in the regulation of gluconeogenic and ureagenic genes remain unclear. We compared the effects of the insulin antagonist S961 and Chrebp deletion on hepatic glycolytic, lipogenic, gluconeogenic, and ureagenic gene expression in mice. S961 markedly increased the plasma glucose, insulin, and 3-OH-butyrate concentrations and reduced the hepatic triglyceride content, but Chrebp deletion had no additive effect. We subsequently estimated the expression of genes involved in the pathways of glycolysis, gluconeogenesis, and lipogenesis. S961 potently decreased both Chrebp and Srebf1c, but Chrebp deletion weakly decreased Srebf1c mRNA expression. Both the S961 and Chrebp deletion caused decreases in glycolytic (Gck and Pklr) and lipogenic (Fasn, Scd1, Me1, Spot14, Elovl6) gene expression. S961 increased the expression of many gluconeogenic genes (G6pc, Fbp1, Aldob, Slc37a4, Pck), whereas Chrebp deletion reduced the expression of gluconeogenic genes other than Pck1. Finally, we checked the metabolites and gene expression in the ureagenesis pathway. S961 increased ureagenic gene (Arg1, Asl, Ass1, Cps1, Otc) expression, which was consistent with the metabolite data: there were reductions in the concentrations of glutamate and aspartate and increases in those of citrulline, ornithine, urea, and proline. However, Chrebp deletion had no additive effect on ureagenesis. In conclusion, insulin rather than glucose regulate ureagenic gene expression, whereas glucose and insulin regulate gluconegenic gene expression in opposite directions.

Type 2 diabetes mellitus (T2DM), a metabolic disorder, has the hallmarks of persistent hyperglycemia, insulin resistance, and dyslipidemia. Protein-tyrosine phosphatase 1B (PTP1B) was found to be overexpressed in many tissues in the case of T2DM and involved in the negative regulation of insulin signaling. So, PTP1B inhibition can act as a therapeutic target for T2DM. Numerous studies claimed the anti-inflammatory, hypoglycemic, hepatoprotective, and hypolipidemic activities of Dodonaea viscosa. Previously, we generated the high-fat diet (HFD)-low dose streptozotocin (STZ)-induced diabetic male mice model and treated it with a PTP1B inhibitor (5, 7-dihydroxy-3, 6-dimethoxy-2- (4-methoxy-3- (3-methyl-2-enyl) phenyl)-4H-chromen-4-one), isolated from Dodonaea viscosa. In the current study, we aimed to investigate the De novo lipogenesis, adipocyte differentiation, augmentation of lipoproteins clearance, fatty acid uptake, antilipolysis activity, and hepatic steatosis of PTP1B inhibition in adipose and liver tissues of the HFD-STZ-induced diabetic mice model. We found the retrieval of normal morphology of adipocytes and hepatocytes in the compound-treated group. The biochemical parameters showed the gradual reduction of LDL, VLDL, TC, and TG in the serum of the compound-treated group. To further test our hypothesis, real-time PCR was performed, and data revealed the reduction of PTP1B and other inflammatory markers in both tissues, showing enhanced expression of insulin signaling markers (INSR, IRS1, IRS2, and PI3K). Our compound upregulated the adipogenic (PPARγ), lipogenic (SREBP1c, FAS, ACC, and DGAT2), lipoprotein clearance (LPL, LDLR, and VLDLR), fatty acid uptake (CD36 and FATP1), and lipid droplet forming (FSP27 and perilipin-1) markers expressions in adipocytes and downregulated in hepatocytes. Furthermore, we found elevated cholesterol efflux (in adipose and liver) and decreased lipolysis in adipocytes and elevated in hepatocytes. Hence, we can conclude that our compound protects the adipocytes from abrupt lipolysis and stimulates adipocyte differentiation. In addition, it plays a hepatic protective role by shifting clearance and uptake of lipoproteins and fatty acids to the peripheral tissues and retrieving the fatty liver condition.

Steatotic liver disease (SLD) and Hepatocellular Carcinoma (HCC) are characterised by a substantial rewiring of lipid fluxes caused by systemic metabolic unbalances and/or disrupted intracellular metabolic pathways. SLD is a direct consequence of the interaction between genetic predisposition and a chronic positive energy balance affecting whole-body energy homeostasis and the function of metabolically-competent organs. In this review, we discuss how the impairment of the cross-talk between peripheral organs and the liver stalls glucose and lipid metabolism, leading to unbalances in hepatic lipid fluxes that promote hepatic fat accumulation. We also describe how prolonged metabolic stress builds up toxic lipid species in the liver, and how lipotoxicity and metabolic disturbances drive disease progression by promoting a chronic activation of wound healing, leading to fibrosis and HCC. Last, we provide a critical overview of current state of the art (pre-clinical and clinical evidence) regarding mechanisms of action and therapeutic efficacy of candidate SLD treatment options, and their potential to interfere with SLD/HCC pathophysiology by diverting lipids away from the liver therefore improving metabolic health.

Activation of thermogenic brown adipose tissue (BAT) and inducible beige adipose tissue (BeAT) is triggered by environmental or metabolic stimuli, including cold ambient temperatures and nutrient stress. Thioesterase superfamily member 1 (Them1), a long-chain fatty acyl-CoA thioesterase that is enriched in BAT, suppresses acute cold-induced thermogenesis. Here, we demonstrate that Them1 expression was induced in BAT and BeAT by the carbohydrate response element binding protein (ChREBP) in response to chronic cold exposure or to the activation of the integrated stress response (ISR) by nutrient excess. Under either condition, Them1 suppressed energy expenditure. Consequently, mice lacking Them1 in BAT and BeAT exhibited resistance to obesity and glucose intolerance induced by feeding with a high-fat diet. During chronic cold exposure or ISR activation, Them1 accumulated in the nucleus, where it interacted with ChREBP and reduced the expression of its target genes, including those encoding enzymes that mediate glycolysis and de novo lipogenesis. These findings demonstrate that in response to chronic cold- or nutrient-induced stress, the induction of Them1 by ChREBP limits thermogenesis while coordinately reducing glucose utilization and lipid biosynthesis through its distinct cytoplasmic and nuclear activities. Targeted inhibition of Them1 could be a potential therapeutic approach to increase the activity of BAT and BeAT to enhance energy expenditure in the management of obesity-associated metabolic disorders.

De novo lipogenesis (DNL) has been implicated in the development and progression of liver steatosis. Hepatic DNL is strongly influenced by dietary macronutrient composition with diets high in carbohydrate increasing DNL while diets high in fat decrease DNL. The enzymes in the core DNL pathway have been well characterized; however, less is known about other liver proteins that play accessory or regulatory roles. In the current study, we associate measured rates of hepatic DNL and fat content with liver proteomic analysis in mice to identify known and unknown proteins that may have a role in DNL. Male mice were fed either a standard chow diet, a semipurified high starch or high-fat diet. Both semipurified diets resulted in increased body weight, fat mass, and liver triglyceride content compared to chow controls, and hepatic DNL was increased in the high starch and decreased in high fat-fed mice. Proteomic analysis identified novel proteins associated with DNL that are involved in taurine metabolism, suggesting a link between these pathways. There was no relationship between proteins that associated with DNL and those associated with liver triglyceride content. Further analysis identified proteins that are differentially regulated when comparing a nonpurified chow diet to either of the semipurified diets, which provide a set of proteins that are influenced by dietary complexity. Finally, we compared the liver proteome between 4- and 30-week diet-fed mice and found remarkable similarity suggesting that metabolic remodeling of the liver occurs rapidly in response to differing dietary components. Together, these findings highlight novel proteins associated with hepatic DNL independently of liver fat content and suggest rapid liver metabolic remodeling in response to dietary composition changes.

O-Linked β-N-acetylglucosamine (O-GlcNAc) is an essential, dynamic monosaccharide post-translational modification (PTM) found on serine and threonine residues of thousands of nucleocytoplasmic proteins. The installation and removal of O-GlcNAc is controlled by a single pair of enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), respectively. Since its discovery four decades ago, O-GlcNAc has been found on diverse classes of proteins, playing important functional roles in many cellular processes. Dysregulation of O-GlcNAc homeostasis has been implicated in the pathogenesis of disease, including neurodegeneration, X-linked intellectual disability (XLID), cancer, diabetes, and immunological disorders. These foundational studies of O-GlcNAc in disease biology have motivated efforts to target O-GlcNAc therapeutically, with multiple clinical candidates under evaluation. In this review, we describe the characterization and biochemistry of OGT and OGA, cellular O-GlcNAc regulation, development of OGT and OGA inhibitors, O-GlcNAc in pathophysiology, clinical progress of O-GlcNAc modulators, and emerging opportunities for targeting O-GlcNAc. This comprehensive resource should motivate further study into O-GlcNAc function and inspire strategies for therapeutic modulation of O-GlcNAc.

Non-alcoholic fatty liver disease (NAFLD) is a chronic liver condition closely associated with metabolic syndrome, with its incidence rate continuously rising globally. Recent studies have shown that the development of NAFLD is associated with insulin resistance, lipid metabolism disorder, oxidative stress and endoplasmic reticulum stress. Therapeutic strategies for NAFLD include lifestyle modifications, pharmacological treatments, and emerging biological therapies; however, there is currently no specific drug to treat NAFLD. However Chinese herb medicine (CHM) has shown potential in the treatment of NAFLD due to its unique therapeutic concepts and methods for centuries in China. This review aims to summarize the pathogenesis of NAFLD and some CHMs that have been shown to have therapeutic effects on NAFLD, thus enriching the scientific connotation of TCM theories and facilitating the exploration of TCM in the treatment of NAFLD.

Glycogen-storing so-called clear cell kidney tubules (CCTs), precursor lesions of renal cell carcinoma, have been described in diabetic rats and in humans. The lesions show upregulation of the Akt/mTOR-pathway and the related transcription factor carbohydrate responsive element binding protein (ChREBP), which is supposedly pro-oncogenic. We investigated the effect of ChREBP-knockout on nephrocarcinogenesis in streptozotocin-induced diabetic and normoglycemic mice. Diabetic, but not non-diabetic mice, showed CCTs at 3, 6 and 12 months of age. Glycogenosis was confirmed by periodic acid schiff reaction and transmission electron microscopy. CCTs in ChREBP-knockout mice consisted of larger cells and occurred more frequently compared to wildtype mice. Progression towards kidney tumors was observed in both diabetic groups but occurred earlier in ChREBP-knockout mice. Proliferative activity assessed by BrdU-labeling was lower in 1-week-old but higher in 12-month-old diabetic ChREBP-knockout mice. Surprisingly, renal neoplasms occurred spontaneously in non-diabetic ChREBP-knockout, but not non-diabetic wildtype mice, indicating an unexpected tumor-suppressive function of ChREBP. Immunohistochemistry showed upregulated glycolysis and lipogenesis, along with activated Akt/mTOR-signaling in tumors of ChREBP-knockout groups. Immunohistochemistry of human clear cell renal cell carcinomas revealed reduced ChREBP expression compared to normal kidney tissue. However, the molecular mechanisms by which loss of ChREBP might facilitate tumorigenesis require further investigation.

Bile acids are the end products of cholesterol catabolism. Hepatic bile acid synthesis accounts for a major fraction of daily cholesterol turnover in humans. Biliary secretion of bile acids generates bile flow and facilitates biliary secretion of lipids, endogenous metabolites, and xenobiotics. In intestine, bile acids facilitate the digestion and absorption of dietary lipids and fat-soluble vitamins. Through activation of nuclear receptors and G protein-coupled receptors and interaction with gut microbiome, bile acids critically regulate host metabolism and innate and adaptive immunity and are involved in the pathogenesis of cholestasis, metabolic dysfunction-associated steatotic liver disease, alcohol-associated liver disease, type-2 diabetes, and inflammatory bowel diseases. Bile acids and their derivatives have been developed as potential therapeutic agents for treating chronic metabolic and inflammatory liver diseases and gastrointestinal disorders. SIGNIFICANCE STATEMENT: Bile acids facilitate biliary cholesterol solubilization and dietary lipid absorption, regulate host metabolism and immunity, and modulate gut microbiome. Targeting bile acid metabolism and signaling holds promise for treating metabolic and inflammatory diseases.

Carbohydrate Response Element-Binding Protein (ChREBP) is a transcription factor that activates key genes involved in glucose, fructose, and lipid metabolism in response to carbohydrate feeding, but its other potential roles in metabolic homeostasis have not been as well studied. We used liver-selective GalNAc-siRNA technology to suppress expression of ChREBP in rats fed a high fat/high sucrose diet and characterized hepatic and systemic responses by integrating transcriptomic and metabolomic analyses. GalNAc-siChREBP-treated rats had lower levels of multiple short-chain acyl CoA metabolites compared to rats treated with GalNAc-siCtrl containing a non-targeting siRNA sequence. These changes were related to a sharp decrease in free CoA levels in GalNAc-siChREBP treated-rats, accompanied by lower expression of transcripts encoding enzymes and transporters involved in CoA biosynthesis. These activities of ChREBP likely contribute to its complex effects on hepatic lipid and energy metabolism. While core enzymes of fatty acid (FA) oxidation are induced by ChREBP knockdown, accumulation of liver acylcarnitines and circulating ketones indicate diversion of acetyl CoA to ketone production rather than complete oxidation in the TCA cycle. Despite strong suppression of pyruvate kinase and activation of pyruvate dehydrogenase, pyruvate levels were maintained, likely via increased expression of pyruvate transporters, and decreased expression of lactate dehydrogenase and alanine transaminase. GalNAc-siChREBP treatment increased hepatic citrate and isocitrate levels while decreasing levels of distal TCA cycle intermediates. The drop in free CoA levels, needed for the 2-ketoglutarate dehydrogenase reaction, as well as a decrease in transcripts encoding the anaplerotic enzymes pyruvate carboxylase, glutamate dehydrogenase, and aspartate transaminase likely contributed to these effects. GalNAc-siChREBP treatment caused striking increases in PRPP and ZMP/AICAR levels, and decreases in GMP, IMP, AMP, NaNM, NAD(P), and NAD(P)H levels, accompanied by reduced expression of enzymes that catalyze late steps in purine and NAD synthesis. ChREBP suppression also increased expression of a set of plasma membrane amino acid transporters, possibly as an attempt to replenish TCA cycle intermediates. In sum, combining transcriptomic and metabolomic analyses has revealed regulatory functions of ChREBP that go well beyond its canonical roles in control of carbohydrate and lipid metabolism to now include mitochondrial metabolism and cellular energy balance.

The "Mlx" and "Myc" transcription factor networks cross-communicate and share many common gene targets. Myc's activity depends upon its heterodimerization with Max, whereas the Mlx Network requires that the Max-like factor Mlx associate with the Myc-like factors MondoA or ChREBP. The current work demonstrates that body-wide Mlx inactivation, like that of Myc, accelerates numerous aging-related phenotypes pertaining to body habitus and metabolism. The deregulation of numerous aging-related Myc target gene sets is also accelerated. Among other functions, these gene sets often regulate ribosomal and mitochondrial structure and function, genomic stability, and aging. Whereas "MycKO" mice have an extended lifespan because of a lower cancer incidence, "MlxKO" mice have normal lifespans and a higher cancer incidence. Like Myc, the expression of Mlx, MondoA, and ChREBP and their control over their target genes deteriorate with age in both mice and humans. Collectively, these findings underscore the importance of lifelong and balanced cross-talk between the two networks to maintain proper function and regulation of the many factors that can affect normal aging.

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).

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.

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.

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.

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.

Carbohydrate-responsive element-binding protein (ChREBP) is a transcription factor that regulates several metabolic genes, including the lipogenic enzymes necessary for the metabolic conversion of carbohydrates into lipids. Although the crucial role of ChREBP in the liver, the primary site of de novo lipogenesis, has been studied, its functional role in adipose tissues, particularly brown adipose tissue (BAT), remains unclear. In this study, we investigated the role of ChREBP in BAT under conditions of a high-carbohydrate diet (HCD) and ketogenic diet (KD), represented by extremely low carbohydrate intake.

Using an adeno-associated virus and Cas9 knock-in mice, we rapidly generated Chrebp brown adipocyte-specific knock-out (B-KO) mice, bypassing the necessity for prolonged breeding by using the Cre-Lox system.

We demonstrated that ChREBP is essential for glucose metabolism and lipogenic gene expression in BAT under HCD conditions in Chrebp B-KO mice. After nutrient intake, Chrebp B-KO attenuated the KD-induced expression of several inflammatory genes in BAT.

Our results indicated that ChREBP, a nutrient-sensing regulator, is indispensable for expressing a diverse range of metabolic genes in BAT.

Triokinase/FMN cyclase (Tkfc) is involved in fructose metabolism and is responsible for the phosphorylation of glyceraldehyde to glyceraldehyde-3-phosphate. In this study, we showed that refeeding induced hepatic expression of Tkfc in mice. Luciferase reporter gene assays using the Tkfc promoter revealed the existence of 2 hepatocyte nuclear factor 4α (HNF4α)-responsive elements (HNF4RE1 and HNF4RE2) and 1 carbohydrate-responsive element-binding protein (ChREBP)-responsive element (ChoRE1). Deletion and mutation of HNF4RE1 and HNF4RE2 or ChoRE1 abolished HNF4α and ChREBP responsiveness, respectively. HNF4α and ChREBP synergistically stimulated Tkfc promoter activity. ChoRE1 mutation attenuated but maintained HNF4α responsiveness, whereas HNF4RE1 and HNF4RE2 mutations abolished ChREBP responsiveness. Moreover, Tkfc promoter activity stimulation by ChREBP was attenuated upon HNF4α knockdown. Furthermore, Tkfc expression was decreased in the livers of ChREBP-/- and liver-specific HNF4-/- (Hnf4αΔHep) mice. Altogether, our data indicate that Tkfc is a target gene of ChREBP and HNF4α, and Tkfc promoter activity stimulation by ChREBP requires HNF4α.

Non-alcoholic fatty liver disease (NAFLD) is a major issue because it is closely associated with metabolic diseases. Advanced glycation end products (AGEs) are implicated as risk factors for steatosis during NAFLD progression. AGEs influence NAFLD progression through a receptor-independent pathway involving AGE cross-link formation and a receptor-dependent pathway that binds to receptors like receptors for advanced glycation end products (RAGE). The objectives of this study are to examine the effect of Lindera obtusiloba Blume (LO) on NAFLD promoted by Nε-(carboxymethyl)lysine (CML), one of the most common dietary AGEs. The anti-glycation effects of LO were evaluated by inhibiting the AGEs formation and AGEs-collagen cross-links breaking. The efficacy of LO against NAFLD promoted by CML was assessed using both in vitro and in vivo models. NAFLD was induced in mice by feeding a high-fat diet and orally administering CML over a period of 12 weeks, and the effects of LO on lipid metabolism and its regulatory mechanisms were investigated. LO showed the effect of inhibited AGEs formation and breakage, and collagen cross-linking. Fed a high-fat diet with administered CML by gavage, LO administration resulted in a reduction in body weight, fat mass, serum triglycerides, total cholesterol, and low-density lipoprotein cholesterol levels. LO reduced hepatic CML accumulation and RAGE expression in mice fed a high-fat diet and orally administered CML. LO alleviated hepatic steatosis accompanied by lipid accumulation and histological damage by suppressing the expression of sterol regulatory element-binding protein 1c, carbohydrate response element binding protein, fatty acid synthase, stearoyl-CoA desaturase1, tumor necrosis factor-α, and interleukin-1β. LO alleviated the MAPK/NF-κB expression by attenuating CML and RAGE expression. Taken together, our results demonstrate that LO alleviates the progression of NAFLD by lowering the levels of AGEs by downregulating CML/RAGE expression.

Dietary restriction (DR) protocols frequently employ intermittent fasting. Following a period of fasting, meal consumption increases lipogenic gene expression, including that of NADPH-generating enzymes that fuel lipogenesis in white adipose tissue (WAT) through the induction of transcriptional regulators SREBP-1c and CHREBP. SREBP-1c knockout mice, unlike controls, did not show an extended lifespan on the DR diet. WAT cytoplasmic NADPH is generated by both malic enzyme 1 (ME1) and the pentose phosphate pathway (PPP), while liver cytoplasmic NADPH is primarily synthesized by folate cycle enzymes provided one-carbon units through serine catabolism. During the daily fasting period of the DR diet, fatty acids are released from WAT and are transported to peripheral tissues, where they are used for beta-oxidation and for phospholipid and lipid droplet synthesis, where monounsaturated fatty acids (MUFAs) may activate Nrf1 and inhibit ferroptosis to promote longevity. Decreased WAT NADPH from PPP gene knockout stimulated the browning of WAT and protected from a high-fat diet, while high levels of NADPH-generating enzymes in WAT and macrophages are linked to obesity. But oscillations in WAT [NADPH]/[NADP+] from feeding and fasting cycles may play an important role in maintaining metabolic plasticity to drive longevity. Studies measuring the WAT malate/pyruvate as a proxy for the cytoplasmic [NADPH]/[NADP+], as well as studies using fluorescent biosensors expressed in the WAT of animal models to monitor the changes in cytoplasmic [NADPH]/[NADP+], are needed during ad libitum and DR diets to determine the changes that are associated with longevity.

Compromised hepatic fatty acid oxidation (FAO) has been observed in human MASH patients and animal models of MASLD/MASH. It remains poorly understood how and when the hepatic FAO pathway is suppressed during the progression of MASLD towards MASH. Hepatic ChREBP⍺ is a classical lipogenic transcription factor that responds to the intake of dietary sugars.

We examined its role in regulating hepatocyte fatty acid oxidation (FAO) and the impact of hepatic Chrebpa deficiency on sensitivity to diet-induced MASLD/MASH in mice.

We discovered that hepatocyte ChREBP⍺ is both necessary and sufficient to maintain FAO in a cell-autonomous manner independently of its DNA-binding activity. Supplementation of synthetic PPAR⍺/δ agonist is sufficient to restore FAO in Chrebp-/- primary mouse hepatocytes. Hepatic ChREBP⍺ was decreased in mouse models of diet-induced MAFSLD/MASH and in patients with MASH. Hepatocyte-specific Chrebp⍺ knockout impaired FAO, aggravated liver steatosis and inflammation, leading to early-onset fibrosis in response to diet-induced MASH. Conversely, liver overexpression of ChREBP⍺-WT or its non-lipogenic mutant enhanced FAO, reduced lipid deposition, and alleviated liver injury, inflammation, and fibrosis. RNA-seq analysis identified the CYP450 epoxygenase (CYP2C50) pathway of arachidonic acid metabolism as a novel target of ChREBP⍺. Over-expression of CYP2C50 partially restores hepatic FAO in primary hepatocytes with Chrebp⍺ deficiency and attenuates preexisting MASH in the livers of hepatocyte-specific Chrebp⍺-deleted mice.

Our findings support the protective role of hepatocyte ChREBPa against diet-induced MASLD/MASH in mouse models in part via promoting CYP2C50-driven FAO.

Lipids, the primary constituents of the cell membrane, play essential roles in nearly all cellular functions, such as cell-cell recognition, signaling transduction, and energy provision. Lipid metabolism is necessary for the maintenance of life since it regulates the balance between the processes of synthesis and breakdown. Increasing evidence suggests that cancer cells exhibit abnormal lipid metabolism, significantly affecting their malignant characteristics, including self-renewal, differentiation, invasion, metastasis, and drug sensitivity and resistance. Prominent oncogenic signaling pathways that modulate metabolic gene expression and elevate metabolic enzyme activity include phosphoinositide 3-kinase (PI3K)/AKT, MAPK, NF-kB, Wnt, Notch, and Hippo pathway. Conversely, when metabolic processes are not regulated, they can lead to malfunctions in cellular signal transduction pathways. This, in turn, enables uncontrolled cancer cell growth by providing the necessary energy, building blocks, and redox potentials. Therefore, targeting lipid metabolism-associated oncogenic signaling pathways could be an effective therapeutic approach to decrease cancer incidence and promote survival. This review sheds light on the interactions between lipid reprogramming and signaling pathways in cancer. Exploring lipid metabolism as a target could provide a promising approach for creating anticancer treatments by identifying metabolic inhibitors. Additionally, we have also provided an overview of the drugs targeting lipid metabolism in cancer in this review.

Insulin resistance (IR) is a major pathogenic factor in the progression of MASLD. In the liver, insulin suppresses gluconeogenesis and enhances de novo lipogenesis (DNL). During IR, there is a defect in insulin-mediated suppression of gluconeogenesis, but an unrestrained increase in hepatic lipogenesis persists. The mechanism of increased hepatic steatosis in IR is unclear and remains controversial. The key discrepancy is whether insulin retains its ability to directly regulate hepatic lipogenesis. Blocking insulin/IRS/AKT signaling reduces liver lipid deposition in IR, suggesting insulin can still regulate lipid metabolism; hepatic glucose metabolism that bypasses insulin's action may contribute to lipogenesis; and due to peripheral IR, other tissues are likely to impact liver lipid deposition. We here review the current understanding of insulin's action in governing different aspects of hepatic lipid metabolism under normal and IR states, with the purpose of highlighting the essential issues that remain unsettled.

Regulation of the thermogenic response by brown adipose tissue (BAT) is an important component of energy homeostasis with implications for the treatment of obesity and diabetes. Our preliminary analyses of RNA-Seq data uncovered many nodes representing epigenetic modifiers that are altered in BAT in response to chronic thermogenic activation. Thus, we hypothesized that chronic thermogenic activation broadly alters epigenetic modifications of DNA and histones in BAT.

Motivated to understand how BAT function is regulated epigenetically, we developed a novel method for the first-ever unbiased top-down proteomic quantitation of histone modifications in BAT and validated our results with a multi-omic approach. To test our hypothesis, wildtype male C57BL/6J mice were housed under chronic conditions of thermoneutral temperature (TN, 28°C), mild cold/room temperature (RT, 22°C), or severe cold (SC, 8°C) and BAT was analyzed for DNA methylation and histone modifications. Methylation of promoters and intragenic regions in genomic DNA decrease in response to chronic cold exposure. Integration of DNA methylation and RNA expression datasets suggest a role for epigenetic modification of DNA in regulation of gene expression in response to cold. In response to cold housing, we observe increased bulk acetylation of histones H3.2 and H4, increased histone H3.2 proteoforms with di- and trimethylation of lysine 9 (K9me2 and K9me3), and increased histone H4 proteoforms with acetylation of lysine 16 (K16ac) in BAT.

Our results reveal global epigenetically-regulated transcriptional "on" and "off" signals in murine BAT in response to varying degrees of chronic cold stimuli and establish a novel methodology to quantitatively study histones in BAT, allowing for direct comparisons to decipher mechanistic changes during the thermogenic response. Additionally, we make histone PTM and proteoform quantitation, RNA splicing, RRBS, and transcriptional footprint datasets available as a resource for future research.

In human aging, liver aging per se not only increases susceptibility to liver diseases but also increases vulnerability of other organs given its central role in regulating metabolism. Total liver function tends to be well maintained in the healthy elderly, so liver aging is generally difficult to identify early. In response to this critical challenge, the Aging Biomarker Consortium of China has formulated an expert consensus on biomarkers of liver aging by synthesizing the latest scientific literature, comprising insights from both scientists and clinicians. This consensus provides a comprehensive assessment of biomarkers associated with liver aging and presents a systematic framework to characterize these into three dimensions: functional, imaging, and humoral. For the functional domain, we highlight biomarkers associated with cholesterol metabolism and liver-related coagulation function. For the imaging domain, we note that hepatic steatosis and liver blood flow can serve as measurable biomarkers for liver aging. Finally, in the humoral domain, we pinpoint hepatokines and enzymatic alterations worthy of attention. The aim of this expert consensus is to establish a foundation for assessing the extent of liver aging and identify early signs of liver aging-related diseases, thereby improving liver health and the healthy life expectancy of the elderly population.