Deletion of HNF1α in hepatocytes results in fatty liver-related hepatocellular carcinoma in mice

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.

Impaired RelA signaling and lipid metabolism dysregulation in hepatocytes: driving forces in the progression of metabolic dysfunction-associated steatotic liver disease

RelA, also known as nuclear factor kappa B p65, plays a crucial role in the pathogenesis of various liver diseases. However, the specific role of RelA in hepatocytes during the progression of metabolic dysfunction-associated steatotic liver disease (MASLD) is not well understood. This study explored the relationship between impaired RelA signaling and lipid metabolism disorders in hepatocytes, and how they synergistically contribute to the advancement of MASLD. We assessed the changes, regulatory relationships, and impacts of RelA signaling and lipid metabolism remodeling on disease progression both in vitro and in vivo. During MASLD, there was a decrease in the expression of RelA and hepatocyte nuclear factor 1 alpha (HNF1α), with both factors showing mutual enhancement of each other's expression under normal conditions. This synergistic effect was absent during hepatocyte steatosis. RelA or HNF1α depletion in hepatocytes intensified MASLD symptoms, whereas overexpression of RELA or treatment with necrostatin-1 (a necroptosis inhibitor) or Z-VAD (a caspase inhibitor) significantly mitigated these effects. Mechanistically, during hepatic steatosis, altered lipid profiles exhibited lipotoxicity, inducing hepatocyte apoptosis and necroptosis, whereas endoplasmic reticulum (ER) stress triggered lipid remodeling processes similar to those observed in MASLD. RelA signaling upregulated the expression of activating transcription factor 4 and glucose-regulated protein 78, thereby alleviating ER stress. Impaired RelA signaling remodeled the ER stress response and lipid metabolism, and enhanced lipid accumulation and lipid toxicity. In conclusion, impaired RelA signaling and disrupted lipid metabolism form a detrimental feedback loop in hepatocytes that promotes MASLD progression. Lipid accumulation suppresses RelA signaling, remodeling the ER stress response and exacerbating lipid metabolism disorder, ultimately leading to hepatocyte apoptosis and necroptosis.

Study on the molecular mechanisms of rifaximin in the treatment of non‑alcoholic steatohepatitis based on the Helicobacter‑DCA‑Fxr‑Hnf1α signalling pathway

Non‑alcoholic steatohepatitis (NASH), the more progressive form of non‑alcoholic fatty liver disease, has become a major cause of cirrhosis and liver cancer. The aim of the present study was to investigate the anti‑NASH effect of the nonabsorbable antibiotic rifaximin and its specific molecular mechanisms. A methionine‑choline deficient (MCD) diet was used to induce NASH formation in mice. The mice with NASH were treated with rifaximin to observe its effects on liver fat deposition, hepatocyte inflammation and liver fibrosis. Furthermore, the intestinal microbiota of mice with NASH was analysed by 16S rRNA sequencing and terminal ileal bile acid levels were assessed using liquid chromatography‑electrospray ionization‑tandem mass spectrometry analysis. Furthermore, the correlation between the intestinal microflora and bile acid levels in the terminal ileum was investigated, and the effects of rifaximin on the intestinal Helicobacter‑deoxycholic acid (DCA)‑farnesoid X receptor (Fxr)‑hepatocyte nuclear factor 1α (Hnf1α) signalling pathway were examined. Moreover, analyses of mice after intestinal decontamination with broad‑spectrum antibiotics and of hepatocyte‑specific Hnf1α knockout (Hnf1αH‑KO) mice were used to elucidate the molecular mechanisms by which rifaximin improves NASH. Notably, treatment with rifaximin markedly ameliorated liver steatosis, hepatocyte inflammation and liver fibrosis in mice with MCD diet‑induced NASH. Rifaximin modulated the gut microbiota, especially Helicobacter hepaticus, in mice with NASH. In addition, rifaximin inhibited the intestinal Helicobacter‑DCA‑Fxr‑Hnf1α signalling pathway in mice with NASH. By contrast, rifaximin did not exert an anti‑NASH effect on decontamination‑treated mice or Hnf1αH‑KO mice. Taken together, these results indicated that rifaximin can ameliorate NASH in mice by modulating the Helicobacter‑DCA‑Fxr‑Hnf1α signalling pathway, providing a theoretical basis for the clinical treatment of patients with NASH with rifaximin.

Bletilla striata polysaccharides alleviate metabolic dysfunction-associated steatotic liver disease through enhancing hepatocyte RelA/ HNF1α signaling

BACKGROUND

Bletilla striata polysaccharides (BSP) have antioxidant, immune regulation, and anti-fibrotic activities. However, the therapeutic effect and mechanisms underlying the action of BSP in metabolic dysfunction-associated steatotic liver disease (MASLD) have not been fully understood.

AIM

To investigate the therapeutic effects and mechanisms of BSP on MASLD by centering on the hepatocyte nuclear factor kappa B p65 (RelA)/hepatocyte nuclear factor-1 alpha (HNF1α) signaling.

METHODS

A mouse model of MASLD was induced by feeding with a high-fat-diet (HFD) and a hepatocyte model of steatosis was induced by treatment with sodium oleate (SO) and sodium palmitate (SP). The therapeutic effects of BSP on MASLD were examined in vivo and in vitro. The mechanisms underlying the action of BSP were analyzed for their effect on lipid metabolism disorder, endoplasmic reticulum (ER) stress, and the RelA/HNF1α signaling.

RESULTS

HFD feeding reduced hepatocyte RelA and HNF1α expression, induced ER stress, lipid metabolism disorder, and necroptosis in mice, which were significantly mitigated by treatment with BSP. Furthermore, treatment with BSP or BSP-containing conditional rat serum significantly attenuated the sodium oleate/sodium palmitate (SO/SP)-induced hepatocyte steatosis by decreasing lipid accumulation, and lipid peroxidation, and enhancing the expression of RelA, and HNF1α. The therapeutic effects of BSP on MASLD were partially abrogated by RELA silencing in mice and RELA knockout in hepatocytes. RELA silencing or knockout significantly down-regulated HNF1α expression, and remodeled ER stress and oxidative stress responses during hepatic steatosis.

CONCLUSION

Treatment with BSP ameliorates MASLD, associated with enhancing the RelA/HNF1α signaling, remodeling ER stress and oxidative stress responses in hepatocytes.

A meta-analysis of the association between RBP4 rs3758539 genotype and metabolic syndrome factors

AIM

To explore the link between the RBP4 rs3758539 genotype and metabolic syndrome risk factors and whether the impact of this genetic variation displays any potential race discrepancy.

MATERIALS AND METHODS

This meta-analysis followed the PRISMA guidelines and was registered with PROSPERO (registration no. CRD42023407999). PubMed, Web of Science, Embase, Cochrane Library, Google Scholar, Airiti Library and CINAHL databases were used for the study search until October 2023. We evaluated the methodological quality using the Joanna Briggs Institute checklist and determined the correlation using a random-effects meta-analysis.

RESULTS

The results indicated that individuals with the rs3758539 GA/AA genotype had a higher risk profile, including lower high-density lipoprotein levels [correlation: -0.045, 95% confidence interval (CI): -0.080 to -0.009, p = .015, I2 = 46.9%] and higher body mass index (correlation: 0.117, 95% CI: 0.036-0.197, p = .005, I2 = 82.0%), body fat (correlation: 0.098, 95% CI: 0.004-0.191, p = .041, I2 = 64.0%), and low-density lipoprotein levels (correlation: 0.074, 95% CI: 0.010-0.139, p = .024, I2 = 0%), of developing metabolic syndrome than those with the GG genotype. The subgroup analysis maintained a significantly positive correlation between the rs3758539 GA/AA genotype and body mass index (correlation: 0.163, 95% CI: 0.031-0.289, p = .016, I2 = 88.9%) but a negative correlation with high-density lipoprotein levels (correlation: -0.047, 95% CI: -0.087 to -0.006, p = .025, I2 = 65.7%) in the Asian group only.

CONCLUSION

The current meta-analysis supports a significant link between the RBP4 rs3758539 GA/AA genotype and the metabolic syndrome.

Gene expression in the liver of the hagfish (Eptatretus burgeri) belonging to the Cyclostomata is ancestral to that of mammals

Although the liver of the hagfish, an earliest diverged lineage among vertebrates, has a histological architecture similar to that of mammals, its gene expression has not been explored yet. The present study was undertaken to comparatively characterize gene expression in the liver of the hagfish with that of the mouse, using in situ hybridization technique. Expression of alb (albumin) was detectable in all hepatocytes of the hagfish liver, but was negative in intrahepatic bile ducts. Their expression in abundant periportal ductules was weak. The expression pattern basically resembled that in mammalian livers, indicating that the differential expression of hepatocyte markers in hepatocytes and biliary cells may have been acquired in ancestral vertebrates. alb expression was almost homogeneous in the hagfish liver, whereas that in the mouse liver lobule was zonal. The glul (glutamate-ammonia ligase) expression was also homogeneously detectable in hepatocytes without zonation, and weakly so in biliary cells of the hagfish, which contrasted with its restricted pericentral expression in mouse livers. These findings indicated that the hagfish liver did not have mammalian-type zonation. Whereas tetrapods had Hnf (hepatocyte nuclear factor) 1a and Hnf1b genes encoding the transcription factors, the hagfish had a single gene of their orthologue hnf1. Although HNF1α and HNF1β were immunohistochemically detected in hepatocytes and biliary cells of the mouse, respectively, hnf1 was expressed in both hepatocytes and biliary cells of the hagfish. These data indicate that gene expression of hnf1 in the hagfish liver may be ancestral with that of alb and glul during vertebrate evolution.

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.

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.

A transcriptional regulatory network of HNF4α and HNF1α involved in human diseases and drug metabolism

HNF4α and HNF1α are core transcription factors involved in the development and progression of a variety of human diseases and drug metabolism. They play critical roles in maintaining the normal growth and function of multiple organs, mainly the liver, and in the metabolism of endogenous and exogenous substances. The twelve isoforms of HNF4α may exhibit different physiological functions, and HNF4α and HNF1α show varying or even opposing effects in different types of diseases, particularly cancer. Additionally, the regulation of CYP450, phase II drug-metabolizing enzymes, and drug transporters is affected by several factors. This article aims to review the role of HNF4α and HNF1α in human diseases and drug metabolism, including their structures and physiological functions, affected diseases, regulated drug metabolism genes, influencing factors, and related mechanisms. We also propose a transcriptional regulatory network of HNF4α and HNF1α that regulates the expression of target genes related to disease and drug metabolism.

Bicyclol ameliorates advanced liver diseases in murine models via inhibiting the IL-6/STAT3 signaling pathway

Bicyclol, a synthetic hepatoprotective and anti-inflammatory agent approved in China, was widely used to treat various hepatitis accompanied by elevated serum aminotransferases. However, the pharmacological effects and mechanisms of bicyclol on advanced liver diseases, such as fibrosis/cirrhosis and hepatocellular carcinoma (HCC), remain to be explored. Here, we revealed that bicyclol prevents from formatting severe fibrosis, slows the progression of moderate liver fibrosis, accelerates the regression of moderate liver fibrosis, decreases the malignancy of HCC in rat models induced by diethylnitrosamine (DEN), and also blocks steatohepatitis to HCC in mice induced by western diet plus carbon tetrachloride and DEN. The detailed pharmacological mechanism showed that bicyclol alleviates chronic progressive liver diseases by inhibiting the levels of IL-6 and subsequent phosphorylated STAT3. Conclusion: Bicyclol plays significant protective roles in multiply stages of fibrosis/cirrhosis-HCC and nonalcoholic fatty liver disease-related HCC via inhibiting IL-6/STAT3 signaling pathway. Therefore, bicyclol might be a promising therapeutic strategy for treating advanced liver diseases.

Rifaximin Ameliorates Non-alcoholic Steatohepatitis in Mice Through Regulating gut Microbiome-Related Bile Acids

Non-alcoholic steatohepatitis (NASH) is the progressive stage of non-alcoholic fatty liver disease (NAFLD). The non-absorbable antibiotic rifaximin has been used for treatment of irritable bowel syndrome, traveling diarrhea, and hepatic encephalopathy, but the efficacy of rifaximin in NASH patients remains controversial. This study investigated the effects and underlying mechanisms of rifaximin treatment in mice with methionine and choline deficient (MCD) diet-induced NASH. We found that rifaximin greatly ameliorated hepatic steatosis, lobular inflammation, and fibrogenesis in MCD-fed mice. Bacterial 16S rRNA sequencing revealed that the gut microbiome was significantly altered in MCD-fed mice. Rifaximin treatment enriched 13 amplicon sequence variants (ASVs) belonging to the groups Muribaculaceae, Parabacteroides, Coriobacteriaceae_UCG-002, uncultured Oscillospiraceae, Dubosiella, Rikenellaceae_RC9_gut_group, Mucispirillum, and uncultured Desulfovibrionaceae. However, rifaximin treatment also reduced seven ASVs in the groups Aerococcus, Oscillospiraceae, uncultured Ruminococcaceae, Bilophila, Muribaculaceae, Helicobacter, and Alistipes in MCD-fed mice. Bile acid-targeted metabolomic analysis indicated that the MCD diet resulted in accumulation of primary bile acids and deoxycholic acid (DCA) in the ileum. Rifaximin delivery reduced DCA levels in MCD-fed mice. Correlation analysis further showed that DCA levels were associated with differentially abundant ASVs modulated by rifaximin. In conclusion, rifaximin may ameliorate NASH by decreasing ileal DCA through alteration of the gut microbiome in MCD-fed mice. Rifaximin treatment may therefore be a promising approach for NASH therapy in humans.

HNF1A POU Domain Mutations Found in Japanese Liver Cancer Patients Cause Downregulation of HNF4A Promoter Activity with Possible Disruption in Transcription Networks

Hepatocyte nuclear factor 1A (HNF1A) is the master regulator of liver homeostasis and organogenesis and regulates many aspects of hepatocyte functions. It acts as a tumor suppressor in the liver, evidenced by the increased proliferation in HNF1A knockout (KO) hepatocytes. Hence, we postulated that any loss-of-function variation in the gene structure or composition (mutation) could trigger dysfunction, including disrupted transcriptional networks in liver cells. From the International Cancer Genome Consortium (ICGC) database of cancer genomes, we identified several HNF1A mutations located in the functional Pit-Oct-Unc (POU) domain. In our biochemical analysis, we found that the HNF1A POU-domain mutations Y122C, R229Q and V259F suppressed HNF4A promoter activity and disrupted the binding of HNF1A to its target HNF4A promoter without any effect on the nuclear localization. Our results suggest that the decreased transcriptional activity of HNF1A mutants is due to impaired DNA binding. Through structural simulation analysis, we found that a V259F mutation was likely to affect DNA interaction by inducing large conformational changes in the N-terminal region of HNF1A. The results suggest that POU-domain mutations of HNF1A downregulate HNF4A gene expression. Therefore, to mimic the HNF1A mutation phenotype in transcription networks, we performed siRNA-mediated knockdown (KD) of HNF4A. Through RNA-Seq data analysis for the HNF4A KD, we found 748 differentially expressed genes (DEGs), of which 311 genes were downregulated (e.g., HNF1A, ApoB and SOAT2) and 437 genes were upregulated. Kyoto Encyclopedia of Genes and Genomes (KEGG) mapping revealed that the DEGs were involved in several signaling pathways (e.g., lipid and cholesterol metabolic pathways). Protein–protein network analysis suggested that the downregulated genes were related to lipid and cholesterol metabolism pathways, which are implicated in hepatocellular carcinoma (HCC) development. Our study demonstrates that mutations of HNF1A in the POU domain result in the downregulation of HNF1A target genes, including HNF4A, and this may trigger HCC development through the disruption of HNF4A–HNF1A transcriptional networks.

HNF1A：From Monogenic Diabetes to Type 2 Diabetes and Gestational Diabetes Mellitus

Diabetes, a disease characterized by hyperglycemia, has a serious impact on the lives and families of patients as well as on society. Diabetes is a group of highly heterogeneous metabolic diseases that can be classified as type 1 diabetes (T1D), type 2 diabetes (T2D), gestational diabetes mellitus (GDM), or other according to the etiology. The clinical manifestations are more or less similar among the different types of diabetes, and each type is highly heterogeneous due to different pathogenic factors. Therefore, distinguishing between various types of diabetes and defining their subtypes are major challenges hindering the precise treatment of the disease. T2D is the main type of diabetes in humans as well as the most heterogeneous. Fortunately, some studies have shown that variants of certain genes involved in monogenic diabetes also increase the risk of T2D. We hope this finding will enable breakthroughs regarding the pathogenesis of T2D and facilitate personalized treatment of the disease by exploring the function of the signal genes involved. Hepatocyte nuclear factor 1 homeobox A (HNF1α) is widely expressed in pancreatic β cells, the liver, the intestines, and other organs. HNF1α is highly polymorphic, but lacks a mutation hot spot. Mutations can be found at any site of the gene. Some single nucleotide polymorphisms (SNPs) cause maturity-onset diabetes of the young type 3 (MODY3) while some others do not cause MODY3 but increase the susceptibility to T2D or GDM. The phenotypes of MODY3 caused by different SNPs also differ. MODY3 is among the most common types of MODY, which is a form of monogenic diabetes mellitus caused by a single gene mutation. Both T2D and GDM are multifactorial diseases caused by both genetic and environmental factors. Different types of diabetes mellitus have different clinical phenotypes and treatments. This review focuses on HNF1α gene polymorphisms, HNF1A-MODY3, HNF1A-associated T2D and GDM, and the related pathogenesis and treatment methods. We hope this review will provide a valuable reference for the precise and individualized treatment of diabetes caused by abnormal HNF1α by summarizing the clinical heterogeneity of blood glucose abnormalities caused by HNF1α mutation.

Genetic Variation in the Mitochondrial Glycerol-3-Phosphate Acyltransferase Is Associated With Liver Injury

BACKGROUND AND AIMS

Most of the genetic basis of chronic liver disease remains undiscovered.

APPROACH AND RESULTS

To identify genetic loci that modulate the risk of liver injury, we performed genome-wide association studies on circulating levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and total bilirubin across 312,671 White British participants in the UK Biobank. We focused on variants associated with elevations in all four liver biochemistries at genome-wide significance (P < 5 × 10-8 ) and that replicated using Mass General Brigham Biobank in 19,323 European ancestry individuals. We identified a genetic locus in mitochondrial glycerol-3-phosphate acyltransferase (GPAM rs10787429) associated with increased levels of ALT (P = 1.4 × 10-30 ), AST (P = 3.6 × 10-10 ), ALP (P = 9.5 × 10-30 ), and total bilirubin (P = 2.9 × 10-12 ). This common genetic variant was also associated with an allele dose-dependent risk of alcohol-associated liver disease (odd ratio [OR] = 1.34, P = 2.6 × 10-5 ) and fatty liver disease (OR = 1.18, P = 5.8 × 10-4 ) by International Classification of Diseases, 10th Revision codes. We identified significant interactions between GPAM rs10787429 and elevated body mass index in association with ALT and AST (P = 7.1 × 10-9 and 3.95 × 10-8 , respectively), as well as between GPAM rs10787429 and weekly alcohol consumption in association with ALT, AST, and alcohol-associated liver disease (P = 4.0 × 10-2 , 1.6 × 10-2 , and 1.3 × 10-2 , respectively). Unlike previously described genetic variants that are associated with an increased risk of liver injury but confer a protective effect on circulating lipids, GPAM rs10787429 was associated with an increase in total cholesterol (P = 2.0 × 10-17 ), LDL cholesterol (P = 2.0 × 10-10 ), and HDL cholesterol (P = 6.6 × 10-37 ). Single-cell RNA-sequencing data demonstrated hepatocyte-predominant expression of GPAM in cells that co-express genes related to VLDL production (P = 9.4 × 10-103 ).

CONCLUSIONS

Genetic variation in GPAM is associated with susceptibility to liver injury. GPAM may represent a therapeutic target in chronic liver disease.

Disruption of Tumor Suppressors HNF4α/HNF1α Causes Tumorigenesis in Liver

The hepatocyte nuclear factor-4α (HNF4α) and hepatocyte nuclear factor-1α (HNF1α) are transcription factors that influence the development and maintenance of homeostasis in a variety of tissues, including the liver. As such, disruptions in their transcriptional networks can herald a number of pathologies, such as tumorigenesis. Largely considered tumor suppressants in liver cancer, these transcription factors regulate key events of inflammation, epithelial-mesenchymal transition, metabolic reprogramming, and the differentiation status of the cell. High-throughput analysis of cancer cell genomes has identified a number of hotspot mutations in HNF1α and HNF4α in liver cancer. Such results also showcase HNF1α and HNF4α as important therapeutic targets helping us step into the era of personalized medicine. In this review, we update current findings on the roles of HNF1α and HNF4α in liver cancer development and progression. It covers the molecular mechanisms of HNF1α and HNF4α dysregulation and also highlights the potential of HNF4α as a therapeutic target in liver cancer.

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

The present review focuses on the roles and underlying mechanisms of action of hepatic nuclear factor-1 (HNF-1) in lipid metabolism and the development of lipid metabolism disorders. HNF-1 is a transcriptional regulator that can form homodimers, and the HNF-1α and HNF-1β isomers can form heterodimers. Both homo- and heterodimers recognize and bind to specific cis-acting elements in gene promoters to transactivate transcription and to coordinate the expression of target lipid-related genes, thereby influencing the homeostasis of lipid metabolism. HNF-1 was shown to restrain lipid anabolism, including synthesis, absorption, and storage, by inhibiting the expression of lipogenesis-related genes, such as peroxisome proliferator-activated receptor γ (PPARγ) and sterol regulatory element-binding protein-1/2 (SREBP-1/2). Moreover, HNF-1 enhances the expression of various genes, such as proprotein convertase subtilisin/kexin type 9 (PCSK9), glutathione peroxidase 1 (GPx1), and suppressor of cytokine signaling-3 (SOCS-3) and negatively regulates signal transducer and activator of transcription (STAT) to facilitate lipid catabolism in hepatocytes. HNF-1 reduces hepatocellular lipid decomposition, which alleviates the progression of nonalcoholic fatty liver disease (NAFLD). HNF-1 impairs preadipocyte differentiation to reduce the number of adipocytes, stunting the development of obesity. Furthermore, HNF-1 reduces free cholesterol levels in the plasma to inhibit aortic lipid deposition and lipid plaque formation, relieving dyslipidemia and preventing the development of atherosclerotic cardiovascular disease (ASCVD). In summary, HNF-1 transcriptionally regulates lipid-related genes to manipulate intracorporeal balance of lipid metabolism and to suppress the development of lipid metabolism disorders.

Paradoxical functions of long noncoding RNAs in modulating STAT3 signaling pathway in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the lethal and leading types of cancer threatening the globe with a high mortality rate. STAT3 is an oncogenic transcription factor that is aberrantly activated in several human malignancies including HCC. Many STAT3-driven genes control cell proliferation and survival, apoptotic resistance, cell cycle progression, metastasis, and chemotherapeutic resistance. STAT3 signaling is regulated by endogenous modulators such as protein tyrosine phosphatase (PTP), suppressor of cytokine signaling (SOCS), protein inhibitor of activated STAT (PIAS), and various long noncoding RNAs (lncRNAs). Interestingly, lncRNAs have been reported to exhibit oncogenic and tumor suppressor functions, and these effects are mediated through diverse molecular mechanisms including sponging of microRNAs (miRs), transcription activation/inhibition, and epigenetic modifications. In this article, we have discussed the possible role of STAT3 signaling in hepatocarcinogenesis and various mechanisms by which lncRNAs impart their oncogenic or tumor suppressive action by modulating the STAT3 pathway in HCC.

Hepatokines and adipokines in NASH-related hepatocellular carcinoma

The incidence of hepatocellular carcinoma (HCC) is increasing in industrialised societies; this is likely secondary to the increasing burden of non-alcoholic fatty liver disease (NAFLD), its progressive form non-alcoholic steatohepatitis (NASH), and the metabolic syndrome. Cumulative studies suggest that NAFLD-related HCC may also develop in non-cirrhotic livers. However, prognosis and survival do not differ between NAFLD- or virus-associated HCC. Thus, research has increasingly focused on NAFLD-related risk factors to better understand the biology of hepatocarcinogenesis and to develop new diagnostic, preventive, and therapeutic strategies. One important aspect thereof is the role of hepatokines and adipokines in NAFLD/NASH-related HCC. In this review, we compile current data supporting the use of hepatokines and adipokines as potential markers of disease progression in NAFLD or as early markers of NAFLD-related HCC. While much work must be done to elucidate the mechanisms and interactions underlying alterations to hepatokines and adipokines, current data support the possible utility of these factors - in particular, angiopoietin-like proteins, fibroblast growth factors, and apelin - for detection or even as therapeutic targets in NAFLD-related HCC.

Signaling molecules orchestrating liver regenerative medicine

The liver is in charge of more than 500 functions in the human body, which any damage and failure to the liver can significantly compromise human life. Numerous studies are being carried out in regenerative medicine, as a potential driving force, toward alleviating the need for liver donors and fabrication of a 3D-engineered transplantable hepatic tissue. Liver tissue engineering brings three main factors of cells, extracellular matrix (ECM), and signaling molecules together, while each of these three factors tries to mimic the physiological state of the tissue to direct tissue regeneration. Signaling molecules play a crucial role in directing tissue fabrication in liver tissue engineering. When mimicking the natural in vivo process of regeneration, it is tightly associated with three main phases of differentiation, proliferation (progression), and tissue maturation through vascularization while directing each of these phases is highly regulated by the specific signaling molecules. The understanding of how these signaling molecules guide the dynamic behavior of regeneration would be a tool for further tailoring of bioengineered systems to help the liver regeneration with many cellular, molecular, and tissue-level functions. Hence, the signaling molecules come to aid all these phases for further improvements toward the clinical use of liver tissue engineering as the goal.

Emergent Properties of the HNF4α-PPARγ Network May Drive Consequent Phenotypic Plasticity in NAFLD

Non-alcoholic fatty liver disease (NAFLD) is the most common form of chronic liver disease in adults and children. It is characterized by excessive accumulation of lipids in the hepatocytes of patients without any excess alcohol intake. With a global presence of 24% and limited therapeutic options, the disease burden of NAFLD is increasing. Thus, it becomes imperative to attempt to understand the dynamics of disease progression at a systems-level. Here, we decoded the emergent dynamics of underlying gene regulatory networks that were identified to drive the initiation and the progression of NAFLD. We developed a mathematical model to elucidate the dynamics of the HNF4α-PPARγ gene regulatory network. Our simulations reveal that this network can enable multiple co-existing phenotypes under certain biological conditions: an adipocyte, a hepatocyte, and a "hybrid" adipocyte-like state of the hepatocyte. These phenotypes may also switch among each other, thus enabling phenotypic plasticity and consequently leading to simultaneous deregulation of the levels of molecules that maintain a hepatic identity and/or facilitate a partial or complete acquisition of adipocytic traits. These predicted trends are supported by the analysis of clinical data, further substantiating the putative role of phenotypic plasticity in driving NAFLD. Our results unravel how the emergent dynamics of underlying regulatory networks can promote phenotypic plasticity, thereby propelling the clinically observed changes in gene expression often associated with NAFLD.

Case Report: Hepatic Adenoma in a Child With a Congenital Extrahepatic Portosystemic Shunt

Congenital extrahepatic portosystemic shunts (CEPS), previously also described as Abernethy malformations, are rare malformations in which the extrahepatic portal system directly communicates with the vena cava inferior, thereby bypassing the liver. A hypoplastic portal vein (PV) exists in most cases. CEPS have been associated with the development of liver nodules, ranging from mostly focal nodular hyperplasia (FNH) to hepatic adenoma (HA) and even hepatocellular carcinoma (HCC). Tumor development in CEPS may be due to changes in perfusion pressures, oxygen supply or endocrine imbalances. It is important to rule out CEPS in children with liver tumors, because resection could impede future shunt occlusion procedures, and benign masses may regress after shunt occlusion. Here, we review the case of a 9-years-old male with CEPS and hepatic nuclear Factor 1-alpha (HNF-1-alpha) inactivated HA to raise awareness of this condition and review histopathological changes in the liver of CEPS.

Cytotoxic potentials of S. cumini methanolic seed kernel extract in human hepatoma HepG2 cells

Syzygium cumini (Myrtaceae) is commonly called as Jamun or Jambolan. It has antidiabetic, anti-inflammatory, antipyretic, and antioxidant activities. Hepatocellular carcinoma is the most frequent and deadliest cancers worldwide. We investigated the cytotoxic potentials of S. cumini methanolic seed kernel extract against human hepatoma HepG2 cells. HepG2 cells were treated with 10, 20, and 40 μg/mL of seed kernel extract for 24 hours and cytotoxic analysis was performed by MTT assay. S. cumini induced apoptosis related morphological changes in HepG2 cells were analyzed by annexin V and propidium iodide double staining. Nuclear fragmentation and chromatin condensation were analyzed by Hoechst nuclear staining. Mitochondrial membrane potential (MMP) was investigated by 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolyl-carbocyanine iodide (JC-1) staining. Protein expressions of hepatocyte nuclear factor-1α (HFN-1α) was performed using western blotting. S. cumini treatments caused a significant and a concentration-dependent increase in the cytotoxicity of HepG2 cells. S. cumini treatments increased the percentage of cells in an early and late apoptosis stage. This treatment also caused chromatin condensation and nuclear fragmentation. Further, S. cumini treatments decreased MMP and also caused a significant downregulation of HFN-1α protein expression. The present study demonstrated that S. cumini seed extract induced apoptosis in HepG2 cells through decrease in MMP and downregulation of HFN-1α.

The impact of hepatocyte nuclear factor-1α on liver malignancies and cell stemness with metabolic consequences

Hepatocyte nuclear factor-1 alpha (HNF-1α) is a transcription factor expressed predominantly in the liver among other organs. Structurally, it contains POU-homeodomain that binds to DNA and form proteins that help in maintaining cellular homeostasis, controlling metabolism, and differentiating cell lineages. Scientific research over the period of three decades has reported it as an important player in various liver malignancies such as hepatocellular cancers (HCCs), hepatocellular adenoma (HA), and a more specific HNF-1α-inactivated human hepatocellular adenoma (H-HCAs). Abundant clinical and rodent data have noted the downregulation of HNF-1α in parallel with liver malignancies. It is also interesting to notice that the co-occurrence of mutated HNF-1α expression and hepatic carcinomas transpires typically along with metabolic repercussion. Moreover, scientific data implies that HNF-1α exerts its effects on cell stemness and hence can indirectly impact liver malignancies and metabolic functioning. The effects of HNF-1α on cell stemness present a future opportunity to explore a possible and potential breakthrough. Although the mechanism through which inactivated HNF-1α leads to hepatic malignancies remain largely obscure, several key signal molecules or pathways, including TNF-α, SHP-1, CDH17, SIRT, and MIA-2, have been reported to take part in the regulations of HNF-1α. It can be concluded from the present scientific data that HNF-1α has a great potential to serve as a target for liver malignancies and cell stemness.

TGFβ Impairs HNF1α Functional Activity in Epithelial-to-Mesenchymal Transition Interfering With the Recruitment of CBP/p300 Acetyltransferases

The cytokine transforming growth factor β (TGFβ) plays a crucial role in the induction of both epithelial-to-mesenchymal transition (EMT) program and fibro-cirrhotic process in the liver, where it contributes also to organ inflammation following several chronic injuries. All these pathological situations greatly increase the risk of hepatocellular carcinoma (HCC) and contribute to tumor progression. In particular, late-stage HCCs are characterized by constitutive activation of TGFβ pathway and by an EMT molecular signature leading to the acquisition of invasive and metastatic properties. In these pathological conditions, the cytokine has been shown to induce the transcriptional downregulation of HNF1α, a master regulator of the epithelial/hepatocyte differentiation and of the EMT reverse process, the mesenchymal-to-epithelial transition (MET). Therefore, the restoration of HNF1α expression/activity has been proposed as targeted therapeutic strategy for liver fibro-cirrhosis and late-stage HCCs. In this study, TGFβ is found to trigger an early functional inactivation of HNF1α during EMT process that anticipates the effects of the transcriptional downregulation of its own gene. Mechanistically, the cytokine, while not affecting the HNF1α DNA-binding capacity, impaired its ability to recruit CBP/p300 acetyltransferases on target gene promoters and, consequently, its transactivating function. The loss of HNF1α capacity to bind to CBP/p300 and HNF1α functional inactivation have been found to correlate with a change of its posttranslational modification profile. Collectively, the results obtained in this work unveil a new level of HNF1α functional inactivation by TGFβ and contribute to shed light on the early events triggering EMT in hepatocytes. Moreover, these data suggest that the use of HNF1α as anti-EMT tool in a TGFβ-containing microenvironment may require the design of new therapeutic strategies overcoming the TGFβ-induced HNF1α inactivation.

Virus Genotype-Dependent Transcriptional Alterations in Lipid Metabolism and Inflammation Pathways in the Hepatitis C Virus-infected Liver

Despite advances in antiviral therapy, molecular drivers of Hepatitis C Virus (HCV)-related liver disease remain poorly characterised. Chronic infection with HCV genotypes (1 and 3) differ in presentation of liver steatosis and virological response to therapies, both to interferon and direct acting antivirals. To understand what drives these clinically important differences, liver expression profiles of patients with HCV Genotype 1 or 3 infection (n = 26 and 33), alcoholic liver disease (n = 8), and no liver disease (n = 10) were analysed using transcriptome-wide microarrays. In progressive liver disease, HCV genotype was the major contributor to altered liver gene expression with 2151 genes differentially expressed >1.5-fold between HCV Genotype 1 and 3. In contrast, only 6 genes were altered between the HCV genotypes in advanced liver disease. Induction of lipogenic, lipolytic, and interferon stimulated gene pathways were enriched in Genotype 1 injury whilst a broad range of immune-associated pathways were associated with Genotype 3 injury. The results are consistent with greater lipid turnover in HCV Genotype 1 patients. Moreover, the lower activity in inflammatory pathways associated with HCV genotype 1 is consistent with relative resistance to interferon-based therapy. This data provides a molecular framework to explain the clinical manifestations of HCV-associated liver disease.

HNF1α Controls Liver Lipid Metabolism and Insulin Resistance via Negatively Regulating the SOCS-3-STAT3 Signaling Pathway

This study is aimed at evaluating the effects, functions, and mechanism of HNF1α on hepatic glycolipid metabolism. In this study, free fatty acid- (FFA-) induced steatosis of hepatocyte liver cell LO2 was used as an in vitro model. The methods of Oil Red O staining, RT-qPCR, western blot, and immunofluorescence staining were used to detect LO2-regulated HNF1α expression and its effects on FFA-induced LO2 cell steatosis, the insulin signaling and SOCS-3-STAT3 signaling pathways, the expression of lipid metabolism-related regulators, and phosphorylation. With increased FFA induction time, the expression of HNF1α in the LO2 fatty degeneration hepatic cells gradually decreased. Downregulation of HNF1α expression aggravated FFA-induced steatosis of LO2 hepatocytes. HNF1α promotes activation of the insulin pathway and oxidative breakdown of fat and inhibits lipid anabolism. Inhibitors of STAT3 can reverse the regulation of decreased HNF1α expression on the insulin signaling pathway and fat metabolism. We also confirmed this pathway using HNF1α-/- mice combining treatment with STAT3 inhibitor NSC 74859 in vivo. HNF1α regulates hepatic lipid metabolism by promoting the expression of SOCS-3 and negatively regulating the STAT3 signaling pathway.

The HNF1α-regulated lncRNA HNF1A-AS1 reverses the malignancy of hepatocellular carcinoma by enhancing the phosphatase activity of SHP-1

BACKGROUND

Our previous study has demonstrated that hepatocyte nuclear factor 1α (HNF1α) exerts potent therapeutic effects on hepatocellular carcinoma (HCC). However, the molecular mechanisms by which HNF1α reverses HCC malignancy need to be further elucidated.

METHODS

lncRNA microarray was performed to identify the long noncoding RNAs (lncRNAs) regulated by HNF1α. Chromatin immunoprecipitation and luciferase reporter assays were applied to clarify the mechanism of the transcriptional regulation of HNF1α to HNF1A antisense RNA 1 (HNF1A-AS1). The effect of HNF1A-AS1 on HCC malignancy was evaluated in vitro and in vivo. RNA pulldown, RNA-binding protein immunoprecipitation and the Bio-Layer Interferometry assay were used to validate the interaction of HNF1A-AS1 and Src homology region 2 domain-containing phosphatase 1 (SHP-1).

RESULTS

HNF1α regulated the expression of a subset of lncRNAs in HCC cells. Among these lncRNAs, the expression levels of HNF1A-AS1 were notably correlated with HNF1α levels in HCC cells and human HCC tissues. HNF1α activated the transcription of HNF1A-AS1 by directly binding to its promoter region. HNF1A-AS1 inhibited the growth and the metastasis of HCC cells in vitro and in vivo. Moreover, knockdown of HNF1A-AS1 reversed the suppressive effects of HNF1α on the migration and invasion of HCC cells. Importantly, HNF1A-AS1 directly bound to the C-terminal of SHP-1 with a high binding affinity (KD = 59.57 ± 14.29 nM) and increased the phosphatase activity of SHP-1. Inhibition of SHP-1 enzymatic activity substantially reversed the HNF1α- or HNF1A-AS1-induced reduction on the metastatic property of HCC cells.

CONCLUSIONS

Our data revealed that HNF1A-AS1 is a direct transactivation target of HNF1α in HCC cells and involved in the anti-HCC effect of HNF1α. HNF1A-AS1 functions as phosphatase activator through the direct interaction with SHP-1. These findings suggest that regulation of the HNF1α/HNF1A-AS1/SHP-1 axis may have beneficial effects in the treatment of HCC.

p.Q511L mutation of HNF1α in hepatocellular carcinoma suppresses the transcriptional activity and the anti-tumor effect of HNF1α

Hepatocyte nuclear factor 1α (HNF1α) is a liver-enriched transcription factor that regulates many aspects of hepatocyte functions. Our previous studies have demonstrated that HNF1α has potent therapeutic effects on hepatocellular carcinoma (HCC). Mutations in HNF1α gene are frequently associated with maturity-onset diabetes of the young type 3 (MODY3) and hepatocellular adenomas. However, the association of HNF1α mutation and HCC remains elusive. In this study, the point mutation of HNF1α gene with c.A1532 > T/p.Q511L was identified in an HCC patient by exon-capture high-throughput sequencing. Mutation of c.A1532 > T/p.Q511L in HNF1α gene was only detected in the tumor tissue but not in the adjacent non-tumorous liver tissue of the patient. Luciferase reporter assay and real-time PCR revealed that mutation of p.Q511L reduced the transcriptional activity of HNF1α. Immunofluorescence staining and subcellular fraction analysis revealed that mutation of p.Q511L disturbed the intracellular localization of HNF1α in HCC cells. Moreover, the inhibitory effect of HNF1α on the proliferation, migration and invasion in HCC cells was also partially abolished by the mutation of p.Q511L. Our data suggested that the missense mutation of HNF1α (p.Q511L) may associate with the progression of HCC.