Transcriptional control by HNF-1: Emerging evidence showing its role in lipid metabolism and lipid metabolism disorders

Long noncoding RNAs in familial hypercholesterolemia: biomarkers, therapeutics, and AI in precision medicine

Long noncoding RNAs (lncRNAs) have emerged as critical regulators of lipid metabolism, playing pivotal roles in cholesterol biosynthesis, transport, and efflux. Familial Hypercholesterolemia (FH), a genetic disorder characterized by excessive low-density lipoprotein cholesterol (LDL-C) levels, remains a significant contributor to premature cardiovascular disease (CVD). Traditional diagnostic methods, including lipid profiling and genetic testing, have limitations in sensitivity and accessibility, highlighting the need for novel molecular biomarkers. This review delves into the mechanistic involvement of lncRNAs in FH pathogenesis, shedding light on their potential as non-invasive biomarkers and therapeutic targets. Key lncRNAs such as LeXis, CHROME, and H19 have been implicated in cholesterol regulation and atherosclerosis progression, making them attractive candidates for precision medicine applications. Additionally, advancements in AI-driven lncRNA discovery and single-cell transcriptomics are paving the way for innovative diagnostic and therapeutic strategies. Emerging RNA-based therapeutics, including antisense oligonucleotides, small interfering RNAs (siRNAs), and CRISPR-based gene-editing tools, hold promise for modulating lncRNA function to restore lipid homeostasis. However, challenges such as biomarker validation, efficient RNA delivery, and regulatory approval must be addressed for clinical translation. The integration of lncRNA-based approaches into FH management offers new possibilities for early detection, targeted therapy, and personalized cardiovascular risk assessment, underscoring the need for continued research in this rapidly evolving field.

Mechanisms of action of Fucus vesiculosus-derived fucoidan on improving dyslipidemia in New Zealand rabbits fed a high-fat diet

Dyslipidemia is a major contributor to various diseases, including atherosclerotic cardiovascular disease and obesity. Treatment strategies for dyslipidemia continue to evolve as our understanding of this metabolic disorder and potential therapeutic candidates advance. Notably, fucoidan demonstrates promising effects in ameliorating dyslipidemia in rodents, although their lipid metabolism differs significantly from humans. This study, investigates the lipid-regulatory effects of Fucus vesiculosus-derived fucoidan (FvF) and elucidates the underlying mechanisms of action using New Zealand rabbits fed a high-fat diet, whose lipid profiles closely resemble those of patients with dyslipidemia. The results demonstrate that FvF intervention ameliorates dyslipidemia and lipid deposition in a dose-dependent manner. Mechanistically, FvF intervention modulates the expression levels of multiple molecules involved in lipid transport, fatty acid synthesis and beta-oxidation, and redox balance, as revealed by quantitative reverse transcription polymerase chain reaction, western blotting, and proteomic analysis. This study is the first to report that FvF, consisting of alternating [→4)-α-L-Fucp(1 → 3)-α-L-Fucp(1→] glycosyls ameliorates dyslipidemia by directly modulating lipid metabolism and indirectly attenuating oxidative stress. These findings suggest that FvF holds significant potential as a candidate for the treatment of lipid disorder-related diseases.

Chromatin remodeling in lymphocytic function and fate: the multifaceted roles of SWI/SNF complex

The Switch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complex comprises 10-15 subunits, which modulate the arrangement, location, or conformation of nucleosomes to upregulate chromatin accessibility. During lymphocytic differentiation and functional development, the SWI/SNF complex exerts its effects by binding to specific transcription factors (TFs) or DNA sequences via its subunits, which are thereafter recruited to the promoter or enhancer regions of target genes, rendering each subunit crucial wherein. The loss of individual subunits during lymphocytic differentiation not only disrupts the targeting of the SWI/SNF complex but also impairs its chromatin remodeling function, ultimately resulting in altered differentiation of immature lymphocytes, dysfunction of mature lymphocytes, and injured immune responses. Therefore, in this paper, we focus on TFs interacting with SWI/SNF complex subunits in lymphocytes, and summarize the effects of the loss of specific subunits of the SWI/SNF complex on lymphocytic differentiation and function, as well as the modification in the expression of key genes. We also summarize the potential clinical treatments and applications targeting the loss of SWI/SNF complex subunits, and focus on the application in Chimeric Antigen Receptor (CAR) technology. In conclusion, the SWI/SNF complex is a key regulatory factor in lymphocytic biology, involved in fundamental cellular processes and closely associated with hematological diseases and immune dysfunction. However, the specific roles of SWI/SNF complex subunits in different lymphocytic subpopulations remain unclear. Future clarification of the specific functions of these subunits in different lymphocytic subsets is expected to promote the development of immunotherapy and personalized therapy.

Distinct Roles of Common Genetic Variants and Their Contributions to Diabetes: MODY and Uncontrolled T2DM

Type 2 diabetes mellitus (T2DM) encompasses a range of clinical manifestations, with uncontrolled diabetes leading to progressive or irreversible damage to various organs. Numerous genes associated with monogenic diabetes, exhibiting classical patterns of inheritance (autosomal dominant or recessive), have been identified. Additionally, genes involved in complex diabetes, which interact with environmental factors to trigger the disease, have also been discovered. These genetic findings have raised hopes that genetic testing could enhance diagnostics, disease surveillance, treatment selection, and family counseling. However, the accurate interpretation of genetic data remains a significant challenge, as variants may not always be definitively classified as either benign or pathogenic. Research to date, however, indicates that periodic reevaluation of genetic variants in diabetes has led to more consistent findings, with biases being steadily eliminated. This has improved the interpretation of variants across diverse ethnicities. Clinical studies suggest that genetic risk information may motivate patients to adopt behaviors that promote the prevention or management of T2DM. Given that the clinical features of certain monogenic diabetes types overlap with T2DM, and considering the significant role of genetic variants in diabetes, healthcare providers caring for prediabetic patients should consider genetic testing as part of the diagnostic process. This review summarizes current knowledge of the most common genetic variants associated with T2DM, explores novel therapeutic targets, and discusses recent advancements in the pharmaceutical management of uncontrolled T2DM.

Deleting adipose FXR exacerbates metabolic defects and induces endocannabinoid lipid, 2-oleoyl glycerol, in obesity

The nutrient sensor farnesoid X receptor (FXR) transcriptionally regulates whole-body lipid and glucose homeostasis. Several studies examined targeting FXR as a modality to treat obesity with varying conflicting results, emphasizing the need to study tissue-specific roles of FXR. We show that deletion of adipocyte Fxr results in increased adipocyte hypertrophy and suppression of several metabolic genes that is akin to some of the changes noted in high-fat diet (HFD)-fed control mice. Moreover, upon HFD challenge, these effects are worsened in adipocyte-specific Fxr knockout mice. We uncover that FXR regulates fatty acid amide hydrolase (Faah) such that its deletion lowers Faah expression. Conversely, FXR activation by its ligand, chenodeoxycholic acid, induces Faah transcription. Notably, HFD results in the reduction of adipose Faah expression in control mice and that Faah inhibition or deletion is linked to obesity. We report that the adipocyte FXR-Faah axis controls local 2-oleoyl glycerol and systemic N-acyl ethanolamine levels. Taken together, these findings show that loss of adipose FXR may contribute to the pathogenesis of obesity and subsequent metabolic defects.

Palmitic Acid Induced a Dedifferentiation Profile at the Transcriptome Level: A Collagen Synthesis but no Triglyceride Accumulation in Hepatocyte-Like Cells Derived From Human-Induced Pluripotent Stem Cells Cultivated Inside Organ on a Chip

Nonalcoholic fatty liver disease (NAFLD) is one of the main causes of critical liver diseases leading to steatosis, steatohepatitis, fibrosis, and ultimately to liver cirrhosis and hepatic carcinoma. In this study, the effect of palmitic acid (PA), one of the most abundant dietary fatty acids, was investigated using an organ-on-a-chip (OoC) technology on hepatocyte-like cells derived from human-induced pluripotent stem cells (hiPSCs). After 1 week of hepatic maturation, followed by 1 week of exposure, the transcriptomic analysis showed lower liver transcription factor activity. It also revealed that 318 genes were differentially expressed between the control and 0.5-mM PA conditions. The 0.5-mM PA conditions were characterized by the downregulation of hepatic markers (liver transcription factors, phase I and phase II metabolism genes) of lipidic genes (metabolism and transport). In parallel, the 0.5-mM PA treatment upregulated several extracellular matrix genes (such as collagen genes). The physiopathological staining demonstrated no lipid accumulation in our model and confirmed the secretion of collagen in the 0.5-mM PA conditions. However, the production of albumin, the metabolic biotransformation by the cytochrome P450 enzymes, and the biliary acid concentrations were not altered by the PA treatments. Overall, our data illustrated the response to PA characterized by an early stage of dedifferentiation observed at the transcriptomic levels associated with a modification of the collagenic profile but without lipid accumulation. We believe that our model provides new insight of the onset of palmitic lipotoxicity in the early stage of NAFLD.

S100A2 promotes clear cell renal cell carcinoma tumor metastasis through regulating GLUT2 expression

Clear cell renal cell carcinoma (ccRCC) is the predominant subtype of renal cancer and is highly malignant. Despite advances in diagnostics and treatment, the prognosis for ccRCC remains poor. The dual nature (promotion or inhibition) of S100A2 in different cancer types shows the complex involvement of its tumorigenesis, but its effect in ccRCC remains unclear. In this study, we first elucidate the tumor-promoting function of S100A2 in ccRCC by reprogramming glycolysis. Mechanistically, we demonstrate that S100A2 accelerates cancer progression through its interaction with the transcription factor HNF1A, leading to activating GLUT2 transcription. The upregulation of GLUT2 significantly enhances glucose uptake by cancer cells, thereby fueling augmented glucose metabolism and fostering the malignant progression of ccRCC. Collectively, our findings highlight the pivotal role of the S100A2-HNF1A-GLUT2 axis in promoting migration and invasion of ccRCC by amplifying glycolysis and suggest that targeting the S100A2-HNF1A-GLUT2 axis is clinically relevant for the treatment of metastatic ccRCC.

Identification of Candidate Genes for Sebum Deposition in Pekin Ducks Using Genome-Wide Association Studies

BACKGROUND

Sebum deposition is a vital trait influencing meat quality and production efficiency in Pekin ducks. Providing insights into the genetic basis of fat deposition could help improve breeding strategies aimed at producing high-quality meat ducks. This study aimed to identify the genetic mechanisms and lipid metabolism pathways regulating subcutaneous and intramuscular fat deposition in two Pekin duck strains: Nankou No. 1 and Jingdian.

METHODS

A total of 72 male ducks, Nankou No. 1 (n = 36) and Jingdian (n = 36), were raised under controlled conditions for 42 days. On days 28, 35, and 42, ducks from each group were selected and slaughtered, and their subcutaneous and liver tissues were collected to analyze lipid enzyme activities. On day 42, additional ducks from each strain were slaughtered and evaluated for carcass performance, as well as intramuscular and sebum yield. Genome-wide association analysis (GWAS) was conducted in the Nankou No. 1 strain.

CONCLUSION

Our results showed statistically significant differences in intramuscular and subcutaneous fat yield between the two strains, with Nankou No. 1 exhibiting a higher yield than Jingdian (p < 0.05). The GWAS results identified 96 significant single nucleotide polymorphisms (SNPs), associated with sebum deposition. Functional annotation identified ALDH7A1 as a key candidate gene involved in lipid metabolism and fat storage regulation in Pekin ducks, Nankou No. 1 strain. Enzyme activity assays in liver and subcutaneous tissues revealed breed-specific differences in lipid metabolism, aligning with genetic findings. The activities of the lipid enzymes changed over time, suggesting changes in the developmental stages. The results on fat yield and enzymatic activities further align with molecular findings from the GWAS, which identified variations in lipid metabolism pathways. These results highlight genetic markers and biochemical pathways related to fat deposition in Pekin ducks, offering new insights for selective breeding programs aimed at optimizing fat content in meat production. Further research is needed to clarify the specific role of ALDH7A1 in lipid metabolism and its potential to enhance fat deposition traits in poultry.

Integrative pan-cancer analysis reveals a common architecture of dysregulated transcriptional networks characterized by loss of enhancer methylation

Aberrant DNA methylation contributes to gene expression deregulation in cancer. However, these alterations' precise regulatory role and clinical implications are still not fully understood. In this study, we performed expression-methylation Quantitative Trait Loci (emQTL) analysis to identify deregulated cancer-driving transcriptional networks linked to CpG demethylation pan-cancer. By analyzing 33 cancer types from The Cancer Genome Atlas, we identified and confirmed significant correlations between CpG methylation and gene expression (emQTL) in cis and trans, both across and within cancer types. Bipartite network analysis of the emQTL revealed groups of CpGs and genes related to important biological processes involved in carcinogenesis including proliferation, metabolism and hormone-signaling. These bipartite communities were characterized by loss of enhancer methylation in specific transcription factor binding regions (TFBRs) and the CpGs were topologically linked to upregulated genes through chromatin loops. Penalized Cox regression analysis showed a significant prognostic impact of the pan-cancer emQTL in many cancer types. Taken together, our integrative pan-cancer analysis reveals a common architecture where hallmark cancer-driving functions are affected by the loss of enhancer methylation and may be epigenetically regulated.

Transcriptional Control: A Directional Sign at the Crossroads of Adult Hepatic Progenitor Cells' Fates

Hepatic progenitor cells (HPCs) have a bidirectional potential to differentiate into hepatocytes and bile duct epithelial cells and constitute a second barrier to liver regeneration in the adult liver. They are usually located in the Hering duct in the portal vein region where various cells, extracellular matrix, cytokines, and communication signals together constitute the niche of HPCs in homeostasis to maintain cellular plasticity. In various types of liver injury, different cellular signaling streams crosstalk with each other and point to the inducible transcription factor set, including FoxA1/2/3, YB-1, Foxl1, Sox9, HNF4α, HNF1α, and HNF1β. These transcription factors exert different functions by binding to specific target genes, and their products often interact with each other, with diverse cascades of regulation in different molecular events that are essential for homeostatic regulation, self-renewal, proliferation, and selective differentiation of HPCs. Furthermore, the tumor predisposition of adult HPCs is found to be significantly increased under transcriptional factor dysregulation in transcriptional analysis, and the altered initial commitment of the differentiation pathway of HPCs may be one of the sources of intrahepatic tumors. Related transcription factors such as HNF4α and HNF1 are expected to be future targets for tumor treatment.

Liver transcriptome analysis reveal the metabolic and apoptotic responses of Trachinotus ovatus under acute cold stress

Trachinotus ovatus is an economically important fish and has been recommended as a high-quality aquaculture fish breed for the high-quality development of sea ranches in the South China Sea. However, T. ovatus shows intolerance to low temperature, greatly limiting the extension of farming scale, reducing production efficiency in winter, and increasing farming risks. In this study, liver transcriptome analysis was investigated in T. ovatus under acute low temperature conditions (20 and 15 °C) using RNA sequencing (RNA-Seq) technology. Inter-groups differential expression analysis and trend analysis screened 1219 DEGs and four significant profiles (profiles 0, 3, 4, and 7), respectively. GO enrichment analysis showed that these DEGs were mainly related to metabolic process and cell growth and death process. KEGG enrichment analysis found that DEGs were mainly associated with lipid metabolism, carbohydrate metabolism, and cell growth and death, such as gluconeogenesis, glycolysis, fatty acid oxidation, cholesterol biosynthesis, p53 signaling pathway, cell cycle arrest, and apoptotic cell death. Moreover, protein-protein interaction networks identified two hub genes (FOS and JUNB) and some important genes related to metabolic process and cell growth and death process, that corresponding to enrichment analysis. Overall, gluconeogenesis, lipid mobilization, and fatty acid oxidation in metabolic process and cell cycle arrest and apoptotic cell death in cell growth and death process were enhanced, while glycolysis, liver glycogen synthesis and cholesterol biosynthesis in metabolic process were inhibited. The enhancement or attenuatment of metabolic process and cell growth and death process is conducive to maintain energy balance, normal fluidity of cell membrane, normal physiological functions of liver cell, enhancing the tolerance of T. ovatus to cold stress. These results suggested that metabolic process and cell growth and death process play important roles in response to acute cold stress in the liver of T. ovatus. Gene expreesion level analysis showed that acute cold stress at 15 °C was identified as a critical temperature point for T. ovatus in term of cellular metabolism alteration and apoptosis inducement, and rewarming intervention should be timely implemented above 15 °C. Our study can provide theoretical support for breeding cold-tolerant cultivars of T. ovatus, which is contributed to high-quality productions fish production.

Involvement of the vagus nerve and hepatic gene expression in serum adiponectin concentrations in mice

Several humoral factors, such as adiponectin and urate, have been suggested to affect metabolic syndromes. Previously, we reported a reduction in blood adiponectin concentrations after a high-fructose diet partially via the vagus nerve in rats. Although a lithogenic diet (LD), i.e., supplementation of a normal control diet (CT) with 0.6% cholesterol and 0.2% sodium cholate, reduced blood adiponectin concentrations, the involvement of the vagus nerve in this mechanism remains unclear. To estimate the involvement of the vagus nerve in the regulation of blood adiponectin concentrations using an LD, male imprinting control region mice that had been vagotomized (HVx) or only laparotomized (Sham) were administered a CT or an LD for 10 weeks. Serum adiponectin concentrations in the Sham-LD, HVx-CT, and HVx-LD groups were reduced by half compared with the Sham-CT group. The hepatic mRNA levels of fibroblast growth factor 21 (Fgf21), which reportedly stimulates adiponectin secretion from white adipose tissue, were lower in the LD groups compared with the CT groups. HepG2 hepatoma cells showed that various bile acids reduced the mRNA expression of FGF21. Moreover, the LD increased serum urate concentrations and reduced hepatic expressions of the acyl-CoA oxidase 1 (Acox1) mRNA and glucokinase, suggesting insufficient regeneration of ATP from AMP. In conclusion, serum adiponectin concentration may be regulated via the vagus nerve in normal mice, whereas a reduction of hepatic Fgf21 mRNA by bile acids may also lower serum adiponectin levels. Moreover, the LD may promote hepatic AMP accumulation and subsequently increase the serum urate concentration in mice.

The translational potential of miR-26 in atherosclerosis and development of agents for its target genes ACC1/2, COL1A1, CPT1A, FBP1, DGAT2, and SMAD7

Atherosclerosis is one of the leading causes of death worldwide. miR-26 is a potential biomarker of atherosclerosis. Standardized diagnostic tests for miR-26 (MIR26-DX) have been developed, but the fastest progress has been in predicting the efficacy of IFN-α therapy for hepatocellular carcinoma (HCC, phase 3). MiR-26 slows atherosclerosis development by suppressing ACC1/2, ACLY, ACSL3/4, ALDH3A2, ALPL, BMP2, CD36, COL1A1, CPT1A, CTGF, DGAT2, EHHADH, FAS, FBP1, GATA4, GSK3β, G6PC, Gys2, HMGA1, HMGB1, LDLR, LIPC, IL-1β, IL-6, JAG2, KCNJ2, MALT1, β-MHC, NF-κB, PCK1, PLCβ1, PYGL, RUNX2, SCD1, SMAD1/4/5/7, SREBF1, TAB3, TAK1, TCF7L2, and TNF-α expression. Many agents targeting these genes, such as the ACC1/2 inhibitors GS-0976, PF-05221304, and MK-4074; the DGAT2 inhibitors IONIS-DGAT2Rx, PF-06427878, PF-0685571, and PF-07202954; the COL1A1 inhibitor HT-100; the stimulants 68Ga-CBP8 and RCT-01; the CPT1A inhibitors etomoxir, perhexiline, and teglicar; the FBP1 inhibitors CS-917 and MB07803; and the SMAD7 inhibitor mongersen, have been investigated in clinical trials. Interestingly, miR-26 better reduced intima-media thickness (IMT) than PCSK9 or CT-1 knockout. Many PCSK9 inhibitors, including alirocumab, evolocumab, inclisiran, AZD8233, Civi-007, MK-0616, and LIB003, have been investigated in clinical trials. Recombinant CT-1 was also investigated in clinical trials. Therefore, miR-26 is a promising target for agent development. miR-26 promotes foam cell formation by reducing ABCA1 and ARL4C expression. Multiple materials can be used to deliver miR-26, but it is unclear which material is most suitable for mass production and clinical applications. This review focuses on the potential use of miR-26 in treating atherosclerosis to support the development of agents targeting it.

SPOP inhibits HBV transcription and replication by ubiquitination and degradation of HNF1α

Hepatitis B virus (HBV) infection remains a significant public health burden worldwide. The persistence of covalently closed circular DNA (cccDNA) within the nucleus of infected hepatocytes is responsible for the failure of antiviral treatments. The ubiquitin proteasome system (UPS) has emerged as a promising antiviral target, as it can regulate HBV replication by promoting critical protein degradation in steps of viral life cycle. Speckle-type POZ protein (SPOP) is a critical adaptor for Cul3-RBX1 E3 ubiquitin ligase complex, but the effect of SPOP on HBV replication is less known. Here, we identified SPOP as a novel host antiviral factor against HBV infection. SPOP overexpression significantly inhibited the transcriptional activity of HBV cccDNA without affecting cccDNA level in HBV-infected HepG2-NTCP and primary human hepatocyte cells. Mechanism studies showed that SPOP interacted with hepatocyte nuclear factor 1α (HNF1α), and induced HNF1α degradation through host UPS pathway. Moreover, the antiviral role of SPOP was also confirmed in vivo. Together, our findings reveal that SPOP is a novel host factor which inhibits HBV transcription and replication by ubiquitination and degradation of HNF1α, providing a potential therapeutic strategy for the treatment of HBV infection.

MiRNAs in Alcohol-Related Liver Diseases and Hepatocellular Carcinoma: A Step toward New Therapeutic Approaches?

Alcohol-related Liver Disease (ALD) is the primary cause of chronic liver disorders and hepatocellular carcinoma (HCC) development in developed countries and thus represents a major public health concern. Unfortunately, few therapeutic options are available for ALD and HCC, except liver transplantation or tumor resection for HCC. Deciphering the molecular mechanisms underlying the development of these diseases is therefore of major importance to identify early biomarkers and to design efficient therapeutic options. Increasing evidence indicate that epigenetic alterations play a central role in the development of ALD and HCC. Among them, microRNA importantly contribute to the development of this disease by controlling the expression of several genes involved in hepatic metabolism, inflammation, fibrosis, and carcinogenesis at the post-transcriptional level. In this review, we discuss the current knowledge about miRNAs' functions in the different stages of ALD and their role in the progression toward carcinogenesis. We highlight that each stage of ALD is associated with deregulated miRNAs involved in hepatic carcinogenesis, and thus represent HCC-priming miRNAs. By using in silico approaches, we have uncovered new miRNAs potentially involved in HCC. Finally, we discuss the therapeutic potential of targeting miRNAs for the treatment of these diseases.

Sortilin-induced lipid accumulation and atherogenesis are suppressed by HNF1b SUMOylation promoted by flavone of Polygonatum odoratum

This study aims to investigate the impact of hepatocyte nuclear factor 1β (HNF1b) on macrophage sortilin-mediated lipid metabolism and aortic atherosclerosis and explore the role of the flavone of Polygonatum odoratum (PAOA-flavone)-promoted small ubiquitin-related modifier (SUMO) modification in the atheroprotective efficacy of HNF1b. HNF1b was predicted to be a transcriptional regulator of sortilin expression via bioinformatics, dual-luciferase reporter gene assay, and chromatin immunoprecipitation. HNF1b overexpression decreased sortilin expression and cellular lipid contents in THP-1 macrophages, leading to a depression in atherosclerotic plaque formation in low-density lipoprotein (LDL) receptor-deficient (LDLR-/-) mice. Multiple SUMO1-modified sites were identified on the HNF1b protein and co-immunoprecipitation confirmed its SUMO1 modification. The SUMOylation of HNF1b protein enhanced the HNF1b-inhibited effect on sortilin expression and reduced lipid contents in macrophages. PAOA-flavone treatment promoted SUMO-activating enzyme subunit 1 (SAE1) expression and SAE1-catalyzed SUMOylation of the HNF1b protein, which prevented sortilin-mediated lipid accumulation in macrophages and the formation of atherosclerotic plaques in apolipoprotein E-deficient (ApoE-/-) mice. Interference with SAE1 abrogated the improvement in lipid metabolism in macrophage cells and atheroprotective efficacy in vivo upon PAOA-flavone administration. In summary, HNF1b transcriptionally suppressed sortilin expression and macrophage lipid accumulation to inhibit aortic lipid deposition and the development of atherosclerosis. This anti-atherosclerotic effect was enhanced by PAOA-flavone-facilitated, SAE1-catalyzed SUMOylation of the HNF1b protein.

A high fat, high sugar diet induces hepatic Peroxisome proliferator-activated receptor gamma coactivator 1-alpha promoter hypermethylation in male Wistar rats

Previously we reported that a high fat, high sugar (HFHS) diet induced adiposity, hyperinsulinaemia, hyperleptinaemia, hypertriglyceridaemia and increased liver mass in male Wistar rats. In the present study, the mechanisms underlying the increased liver mass were further elucidated by assessing hepatic lipid accumulation and the expression and methylation status of key metabolic genes using histology, quantitative real-time PCR and pyrosequencing, respectively. The HFHS diet induced hepatic steatosis, increased hepatic triglycerides (1.8-fold, p < 0.001), and increased the expression of sterol regulatory element-binding transcription factor 1 (Srebf1) (2.0-fold, p < 0.001) and peroxisome proliferator-activated receptor gamma (Pparg) (1.7-fold, p = 0.017) in the liver. The expression of peroxisome proliferator-activated receptor gamma coactivator 1 alpha (Pgc1a) was decreased (2.6-fold, p < 0.010), which was accompanied by hypermethylation (p = 0.018) of a conserved CpG site in the promoter of Pgc1a in HFHS fed rats compared to controls. In silico analysis identified putative binding sites for CCAAT/enhancer-binding protein beta (C/EBPß) and hepatocyte nuclear factor 1 (HNF1) within proximity to the hypermethylated CpG. As Pgc1a is a co-activator of several transcription factors regulating multiple metabolic pathways, hypermethylation of this conserved CpG site in the promoter of Pgc1a may be one possible mechanism contributing to the development of hepatic steatosis in response to a HFHS diet. However, further work is required to confirm the role of Pgc1a in steatosis.

Research progress in the correlation between SREBP/PCSK9 pathway and lipid metabolism disorders induced by antipsychotics

Antipsychotic medications are commonly used to treat schizophrenia, but they can have negative effects on lipid metabolism, leading to an increased risk of cardiovascular diseases, reduced life expectancy, and difficulties with treatment adherence. The specific mechanisms by which antipsychotics disrupt lipid metabolism are not well understood. Sterol regulatory element-binding proteins (SREBPs) are important transcriptional factors that regulate lipid metabolism. Proprotein convertase subtilisin/kexin type 9 (PCSK9), a gene regulated by SREBPs, plays a critical role in controlling levels of low-density lipoprotein cholesterol (LDL-C) and has become a focus of research on lipid-lowering drugs. Recent studies have shown that antipsychotic drugs can affect lipid metabolism through the SREBP/PCSK9 pathway. A deep understanding of the mechanism for this pathway in antipsychotic drug-related metabolic abnormalities will promote the prevention of lipid metabolism disorders in patients with schizophrenia and the development and application of new drugs.

Dominant-negative HNF1α mutant promotes liver steatosis and inflammation by regulating hepatic complement factor D

Patients with HNF1A variants may develop liver steatosis, while the underlying mechanism is still unclear. Here, we established a mouse model carrying the dominant-negative HNF1α P291fsinsC mutation (hHNF1Amut/-) and found that the mutant mice developed liver steatosis spontaneously under the normal chow diet. Transcriptome analysis showed significant upregulation of Cfd and other genes related to innate immune response in the liver of hHNF1Amut/- mice. The changes in lipid metabolism and complement pathways were also confirmed by proteomics. We demonstrated that HNF1α inhibited CFD expression in hepatocytes, and the P291fsinsC mutant could reverse this inhibitory effect. Furthermore, the suppression of CFD with specific inhibitor or siRNAs reduced triglyceride levels in hepatocytes, suggesting that CFD regulated hepatocyte lipid deposition. Our results demonstrate that the HNF1α P291fsinsC mutant promotes hepatic steatosis and inflammation by upregulating CFD expression, and targeting CFD may delay the progression of nonalcoholic fatty liver disease.

The potential role and mechanism of circRNAs in foam cell formation

Atherosclerosis is a significant risk factor for coronary heart disease (CHD) and myocardial infarction (MI). Atherosclerosis develops during foam cell generation, which is caused by an imbalance in cholesterol uptake, esterification, and efflux. LOX-1, SR-A1, and CD36 all increased cholesterol uptake. ACAT1 and ACAT2 promote free cholesterol (FC) esterification to cholesteryl esters (CE). The hydrolysis of CE to FC was aided by nCEH. FC efflux was promoted by ABCA1, ABCG1, ADAM10, and apoA-I. SR-BI promotes not only cholesterol uptake but also FC efflux. Circular RNAs (circRNAs), which are single-stranded RNAs with a closed covalent circular structure, have emerged as promising biomarkers and therapeutic targets for atherosclerosis due to their highly tissue, cell, and disease state-specific expression profiles. Numerous studies have shown that circRNAs regulate foam cell formation, acting as miRNA sponges to influence atherosclerosis development by regulating the expression of SR-A1, CD36, ACAT2, ABCA1, ABCG1, ADAM10, apoA-I, SR-B1. Several circRNAs, including circ-Wdr91, circ 0004104, circRNA0044073, circRNA_0001805, circDENND1B, circRSF1, circ 0001445, and circRNA 102682, are potential biomarkers for atherosclerosis to better evaluate cardiovascular risk. It is difficult to deliver synthetic therapeutic circRNAs to the desired target tissues. Nanotechnology, such as GA-RM/GZ/PL, may be an important solution to this problem. In this review, we focus on the potential role and mechanism of circRNA/miRNA axis in foam cell formation in the hopes of discovering new targets for the diagnosis, prevention, and treatment of atherosclerosis.

AP-1 is a regulatory transcription factor of inflammaging in the murine kidney and liver

Aging is characterized by chronic low-grade inflammation in multiple tissues, also termed "inflammaging", which represents a significant risk factor for many aging-related chronic diseases. However, the mechanisms and regulatory networks underlying inflammaging across different tissues have not yet been fully elucidated. Here, we profiled the transcriptomes and epigenomes of the kidney and liver from young and aged mice and found that activation of the inflammatory response is a conserved signature in both tissues. Moreover, we revealed links between transcriptome changes and chromatin dynamics through integrative analysis and identified AP-1 and ETS family transcription factors (TFs) as potential regulators of inflammaging. Further in situ validation showed that c-JUN (a member of the AP-1 family) was mainly activated in aged renal and hepatic cells, while increased SPI1 (a member of the ETS family) was mostly induced by elevated infiltration of macrophages, indicating that these TFs have different mechanisms in inflammaging. Functional data demonstrated that genetic knockdown of Fos, a major member of the AP-1 family, significantly attenuated the inflammatory response in aged kidneys and livers. Taken together, our results revealed conserved signatures and regulatory TFs of inflammaging in the kidney and liver, providing novel targets for the development of anti-aging interventions.

The evolving landscape of PCSK9 inhibition in cancer

Cancer is a disease with a significant global burden in terms of premature mortality, loss of productivity, healthcare expenditures, and impact on mental health. Recent decades have seen numerous advances in cancer research and treatment options. Recently, a new role of cholesterol-lowering PCSK9 inhibitor therapy has come to light in the context of cancer. PCSK9 is an enzyme that induces the degradation of low-density lipoprotein receptors (LDLRs), which are responsible for clearing cholesterol from the serum. Thus, PCSK9 inhibition is currently used to treat hypercholesterolemia, as it can upregulate LDLRs and enable cholesterol reduction through these receptors. The cholesterol-lowering effects of PCSK9 inhibitors have been suggested as a potential mechanism to combat cancer, as cancer cells have been found to increasingly rely on cholesterol for their growth needs. Additionally, PCSK9 inhibition has demonstrated the potential to induce cancer cell apoptosis through several pathways, increase the efficacy of a class of existing anticancer therapies, and boost the host immune response to cancer. A role in managing cancer- or cancer treatment-related development of dyslipidemia and life-threatening sepsis has also been suggested. This review examines the current evidence regarding the effects of PCSK9 inhibition in the context of different cancers and cancer-associated complications.

Glucagon-like peptide-1 analog therapy in rare genetic diseases: monogenic obesity, monogenic diabetes, and spinal muscular atrophy

AIM

Implementing genetic analyses have unraveled rare alterations causing early-onset obesity and complications, in whom treatment is challenging. We aimed to report on the effects of adjuvant off-label therapy with liraglutide, glucagon-like peptide-1 analogue (GLP-1a), in rare genetic diagnoses.

METHODS

Case scenarios and review of the literature.

RESULTS

Case 1: Nine-year-old boy with early-onset severe obesity and nonalcoholic fatty liver disease (NAFLD) due to a homozygous mutation in the MC4R gene deteriorated under lifestyle change and metformin therapy [at 10.5 years: body mass index (BMI) 51.2kg/m², 226% of the 95th percentile, fat percentage (FP) 65% and muscle-to-fat ratio (MFR) z-score of -2.41]. One year of liraglutide treatment halted progressive weight gain [BMI 50.3kg/m², 212% of the 95th percentile, 63.7% FP and MFR z-score of -2.34], with biochemical improvement. Case 2: Twelve-year-old boy with obesity presented with diabetes and progressive NAFLD. Exome analysis revealed two heterozygous mutations compatible with monogenic diabetes (HNF1A) and familial hypercholesterolemia (LDLR). Lifestyle modifications resulted in clinical and laboratory improvement (BMI 87th percentile, 32.8% FP, MFR z-score of -1.63, HbA1c 5.5%) without the expected recovery in liver transaminases. Liraglutide treatment augmented the improvement in weight status (BMI 68th percentile, 22.6% FP, MFR z-score of -1.13) with normalization of liver transaminases. Case 3: Nineteen-year-old male with spinal muscular atrophy type 3 presented with sarcopenic obesity and comorbidities. Treatment strategy included dietary counseling and multiple drug therapies (metformin, anti-hypertensive and statins). Liraglutide therapy led to a gradual recovery of metabolic complications allowing tapering-down other medications.

CONCLUSIONS

Considering the pleiotropic effects of GLP1-a beyond BMI reduction, this treatment modality may serve as a game changer in challenging cases.

A Mouse Systems Genetics Approach Reveals Common and Uncommon Genetic Modifiers of Hepatic Lysosomal Enzyme Activities and Glycosphingolipids

Identification of genetic modulators of lysosomal enzyme activities and glycosphingolipids (GSLs) may facilitate the development of therapeutics for diseases in which they participate, including Lysosomal Storage Disorders (LSDs). To this end, we used a systems genetics approach: we measured 11 hepatic lysosomal enzymes and many of their natural substrates (GSLs), followed by modifier gene mapping by GWAS and transcriptomics associations in a panel of inbred strains. Unexpectedly, most GSLs showed no association between their levels and the enzyme activity that catabolizes them. Genomic mapping identified 30 shared predicted modifier genes between the enzymes and GSLs, which are clustered in three pathways and are associated with other diseases. Surprisingly, they are regulated by ten common transcription factors, and their majority by miRNA-340p. In conclusion, we have identified novel regulators of GSL metabolism, which may serve as therapeutic targets for LSDs and may suggest the involvement of GSL metabolism in other pathologies.

Genomic and epigenomic responses to aspirin in human colonic organoids

Aspirin (ASA) is a proven chemoprotective agent for colorectal cancer, though mechanisms underlying these effects are incompletely understood. Human organoids are an ideal system to study genomic and epigenomic host-environment interactions. We use human colonic organoids to profile ASA responses on genome-wide gene expression and chromatin accessibility. Human colonic organoids from one individual were cultured and treated in triplicate with 3 mM ASA or vehicle control (DMSO) for 24 h. Gene expression and chromatin accessibility were measured using RNA- and ATAC-sequencing, respectively. Differentially expressed genes were analyzed using DESeq2. Top genes were validated by qPCR. Gene set enrichment was performed by SetRank. Differentially accessible peaks were analyzed using DiffBind and edgeR. Peak annotation and differential transcription factor motifs were determined by HOMER and diffTF. The results showed robust transcriptional responses to ASA with significant enrichment for fatty acid oxidation and peroxisome proliferator-activated receptor (PPAR) signaling that were validated in independent organoid lines. A large number of differentially accessible chromatin regions were found in response to ASA with significant enrichment for Fos, Jun, and Hnf transcription factor motifs. Integrated analysis of epigenomic and genomic treatment responses highlighted gene regions that could mediate ASA's specific effects in the colon including those involved in chemoprotection and/or toxicity. Assessment of chromatin accessibility and transcriptional responses to ASA yielded new observations about genome-wide effects in the colon facilitated by application of human colonic organoids. This framework can be applied to study colonic ASA responses between individuals and populations in future studies.

Study on fatty acid binding protein in lipid metabolism of livestock and poultry

Fatty acid binding proteins (FABPs) are key proteins in lipid transport, and 12 family members have been documented in the literature. In recent years, new insights have been gained into the structure and function of FABPs, which are important regulators of lipid metabolic processes in the body and play a central role in coordinating lipid transport and metabolism in various tissues and organs across species. This paper provides a brief overview of the structure and biological functions of FABPs and reviews related studies on lipid metabolism in livestock and poultry to lay the foundation for research on the mechanism underlying the regulatory effect of FABPs on lipid metabolism in livestock and poultry and for the genetic improvement of livestock and poultry.