An HNF4α-microRNA-194/192 signaling axis maintains hepatic cell function

Epithelial-mesenchymal transition in tissue repair and degeneration

Epithelial-mesenchymal transitions (EMTs) are the epitome of cell plasticity in embryonic development and cancer; during EMT, epithelial cells undergo dramatic phenotypic changes and become able to migrate to form different tissues or give rise to metastases, respectively. The importance of EMTs in other contexts, such as tissue repair and fibrosis in the adult, has become increasingly recognized and studied. In this Review, we discuss the function of EMT in the adult after tissue damage and compare features of embryonic and adult EMT. Whereas sustained EMT leads to adult tissue degeneration, fibrosis and organ failure, its transient activation, which confers phenotypic and functional plasticity on somatic cells, promotes tissue repair after damage. Understanding the mechanisms and temporal regulation of different EMTs provides insight into how some tissues heal and has the potential to open new therapeutic avenues to promote repair or regeneration of tissue damage that is currently irreversible. We also discuss therapeutic strategies that modulate EMT that hold clinical promise in ameliorating fibrosis, and how precise EMT activation could be harnessed to enhance tissue repair.

Role of Hepatocyte Nuclear Factor 4 Alpha in Liver Cancer

Liver cancer is the sixth most common cancer and the fourth leading cause of cancer-related deaths worldwide. Hepatocellular carcinoma (HCC) is the most prevalent primary liver cancer and the incidence of HCC is on the rise. Liver cancers in general and HCC in particular do not respond to chemotherapy. Radiological ablation, surgical resection, and liver transplantation are the only medical therapies currently available. Hepatocyte nuclear factor 4 α (HNF4α) is an orphan nuclear receptor expressed only in hepatocytes in the liver. HNF4α is considered the master regulator of hepatic differentiation because it regulates a significant number of genes involved in various liver-specific functions. In addition to maintaining hepatic differentiation, HNF4α also acts as a tumor suppressor by inhibiting hepatocyte proliferation by suppressing the expression of promitogenic genes and inhibiting epithelial to mesenchymal transition in hepatocytes. Loss of HNF4α expression and function is associated with rapid progression of chronic liver diseases that ultimately lead to liver cirrhosis and HCC, including metabolism-associated steatohepatitis, alcohol-associated liver disease, and hepatitis virus infection. This review summarizes the role of HNF4α in liver cancer pathogenesis and highlights its potential as a potential therapeutic target for HCC.

Molecular Pathways Governing the Termination of Liver Regeneration

The liver has the unique capacity to regenerate, and up to 70% of the liver can be removed without detrimental consequences to the organism. Liver regeneration is a complex process involving multiple signaling networks and organs. Liver regeneration proceeds through three phases: the initiation phase, the growth phase, and the termination phase. Termination of liver regeneration occurs when the liver reaches a liver-to-body weight that is required for homeostasis, the so-called "hepatostat." The initiation and growth phases have been the subject of many studies. The molecular pathways that govern the termination phase, however, remain to be fully elucidated. This review summarizes the pathways and molecules that signal the cessation of liver regrowth after partial hepatectomy and answers the question, "What factors drive the hepatostat?" SIGNIFICANCE STATEMENT: Unraveling the pathways underlying the cessation of liver regeneration enables the identification of druggable targets that will allow us to gain pharmacological control over liver regeneration. For these purposes, it would be useful to understand why the regenerative capacity of the liver is hampered under certain pathological circumstances so as to artificially modulate the regenerative processes (e.g., by blocking the cessation pathways) to improve clinical outcomes and safeguard the patient's life.

The Pro-Oncogenic Sphingolipid-Metabolizing Enzyme β-Galactosylceramidase Modulates the Proteomic Landscape in BRAF(V600E)-Mutated Human Melanoma Cells

β-Galactosylceramidase (GALC) is a lysosomal enzyme involved in sphingolipid metabolism by removing β-galactosyl moieties from β-galactosylceramide and β-galactosylsphingosine. Previous observations have shown that GALC may exert pro-oncogenic functions in melanoma and Galc silencing, leading to decreased oncogenic activity in murine B16 melanoma cells. The tumor-driving BRAF(V600E) mutation is present in approximately 50% of human melanomas and represents a major therapeutic target. However, such mutation is missing in melanoma B16 cells. Thus, to assess the impact of GALC in human melanoma in a more relevant BRAF-mutated background, we investigated the effect of GALC overexpression on the proteomic landscape of A2058 and A375 human melanoma cells harboring the BRAF(V600E) mutation. The results obtained by liquid chromatography-tandem mass spectrometry (LC-MS/MS) demonstrate that significant differences exist in the protein landscape expressed under identical cell culture conditions by A2058 and A375 human melanoma cells, both harboring the same BRAF(V600E)-activating mutation. GALC overexpression resulted in a stronger impact on the proteomic profile of A375 cells when compared to A2058 cells (261 upregulated and 184 downregulated proteins versus 36 and 14 proteins for the two cell types, respectively). Among them, 25 proteins appeared to be upregulated in both A2058-upGALC and A375-upGALC cells, whereas two proteins were significantly downregulated in both GALC-overexpressing cell types. These proteins appear to be involved in melanoma biology, tumor invasion and metastatic dissemination, tumor immune escape, mitochondrial antioxidant activity, endoplasmic reticulum stress responses, autophagy, and/or apoptosis. Notably, analysis of the expression of the corresponding genes in human skin cutaneous melanoma samples (TCGA, Firehose Legacy) using the cBioPortal for Cancer Genomics platform demonstrated a positive correlation between GALC expression and the expression levels of 14 out of the 27 genes investigated, thus supporting the proteomic findings. Overall, these data indicate for the first time that the expression of the lysosomal sphingolipid-metabolizing enzyme GALC may exert a pro-oncogenic impact on the proteomic landscape in BRAF-mutated human melanoma.

PPARα activation partially drives NAFLD development in liver-specific Hnf4a-null mice

HNF4α regulates various genes to maintain liver function. There have been reports linking HNF4α expression to the development of non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis. In this study, liver-specific Hnf4a-deficient mice (Hnf4aΔHep mice) developed hepatosteatosis and liver fibrosis, and they were found to have difficulty utilizing glucose. In Hnf4aΔHep mice, the expression of fatty acid oxidation-related genes, which are PPARα target genes, was increased in contrast to the decreased expression of PPARα, suggesting that Hnf4aΔHep mice take up more lipids in the liver instead of glucose. Furthermore, Hnf4aΔHep/Ppara-/- mice, which are simultaneously deficient in HNF4α and PPARα, showed improved hepatosteatosis and fibrosis. Increased C18:1 and C18:1/C18:0 ratio was observed in the livers of Hnf4aΔHep mice, and the transactivation of PPARα target gene was induced by C18:1. When the C18:1/C18:0 ratio was close to that of Hnf4aΔHep mouse liver, a significant increase in transactivation was observed. In addition, the expression of Pgc1a, a coactivator of PPARs, was increased, suggesting that elevated C18:1 and Pgc1a expression could contribute to PPARα activation in Hnf4aΔHep mice. These insights may contribute to the development of new diagnostic and therapeutic approaches for NAFLD by focusing on the HNF4α and PPARα signaling cascade.

Palmitic acid-induced microRNA-143-5p expression promotes the epithelial-mesenchymal transition of retinal pigment epithelium via negatively regulating JDP2

BACKGROUND

The epithelial-mesenchymal transition (EMT) of retinal pigment epithelial (RPE) cells is the most crucial step in the etiopathogenesis of proliferative vitreoretinopathy. This study aimed to investigate the role of miR-143-5p in the EMT of RPE cells induced by palmitic acid (PA).

METHODS

ARPE-19 cells were treated with PA to induce EMT, followed by E-cadherin and α-smooth muscle actin (α-SMA) expression and the microRNA expression profile analyses. Subsequently, miR-143-5p mimics/inhibitors, and plasmids expressing its predicted target gene c-JUN-dimerization protein 2 (JDP2), were transfected in ARPE-19 cells using lipofectamine 3000, and followed by PA treatment. Their impacts on EMT were explored using wound healing and Western blot assays. Additionally, miR-143-5p mimics and JDP2-expressing plasmid were co-transfected into ARPE-19 cells and treated with PA to explore whether PA induced EMT of ARPE-19 cells via the miR-143-5p/JDP2 axis.

RESULTS

PA decreased E-cadherin expression and increased those of α-SMA and miR-143-5p. Inhibiting miR-143-5p suppressed the migration of ARPE-19 cells and altered the expressions of E-cadherin and α-SMA. However, additional PA treatment attenuated these alterations. JDP2 was a target of miR-143-5p. Overexpression of JDP2 inhibited the EMT of ARPE-19 cells, resulting in α-SMA downregulation and E-cadherin upregulation, which were reversed by additional PA treatment via inhibiting JDP2 expression. Overexpression of miR-143-5p reversed the effect of JDP2 on the EMT of ARPE-19 cells and additional PA treatment markedly enhanced the effect of miR-143-5p mimics.

CONCLUSION

PA promotes EMT of ARPE-19 cells via regulating the miR-143-5p/JDP2 axis, and these findings provide significant insights into the potential targeting of this axis to treat proliferative vitreoretinopathy.

miR-194 Up-Regulates Cytochrome P450 Family 7 Subfamily A Member 1 Expression via β-Catenin Signaling and Aggravates Cholestatic Liver Diseases

miR-194 is abundantly expressed in hepatocytes, and its depletion induces hepatic resistance to acetaminophen-induced acute injuries. In this study, the biological role of miR-194 in cholestatic liver injury was investigated by using miR-194/miR-192 cluster liver-specific knockout (LKO) mice, in which no liver injuries or metabolic disorders were predisposed. Bile duct ligation (BDL) and 1-naphthyl isothiocyanate (ANIT) were applied to LKO and matched control wild-type (WT) mice to induce hepatic cholestasis. Periportal liver damage, mortality rate, and liver injury biomarkers in LKO mice were significantly less than in WT mice after BDL and ANIT injection. Intrahepatic bile acid level was significantly lower in the LKO liver within 48 hours of BDL- and ANIT-induced cholestasis compared with WT. Western blot analysis showed that β-catenin (CTNNB1) signaling and genes involved in cellular proliferation were activated in BDL- and ANIT-treated mice. The expression levels of cytochrome P450 family 7 subfamily A member 1 (CYP7A1), pivotal in bile synthesis, and its upstream regulator hepatocyte nuclear factor 4α were reduced in primary LKO hepatocytes and liver tissues compared with WT. The knockdown of miR-194 using antagomirs reduced CYP7A1 expression in WT hepatocytes. In contrast, the knockdown of CTNNB1 and overexpression of miR-194, but not miR-192, in LKO hepatocytes and AML12 cells increased CYP7A1 expression. In conclusion, the results suggest that the loss of miR-194 ameliorates cholestatic liver injury and may suppress CYP7A1 expression via activation of CTNNB1 signaling.

Loss of liver function in chronic liver disease: An identity crisis

Adult hepatocyte identity is constructed throughout embryonic development and fine-tuned after birth. A multinodular network of transcription factors, along with pre-mRNA splicing regulators, define the transcriptome, which encodes the proteins needed to perform the complex metabolic and secretory functions of the mature liver. Transient hepatocellular dedifferentiation can occur as part of the regenerative mechanisms triggered in response to acute liver injury. However, persistent downregulation of key identity genes is now accepted as a strong determinant of organ dysfunction in chronic liver disease, a major global health burden. Therefore, the identification of core transcription factors and splicing regulators that preserve hepatocellular phenotype, and a thorough understanding of how these networks become disrupted in diseased hepatocytes, is of high clinical relevance. In this context, we review the key players in liver differentiation and discuss in detail critical factors, such as HNF4α, whose impairment mediates the breakdown of liver function. Moreover, we present compelling experimental evidence demonstrating that restoration of core transcription factor expression in a chronically injured liver can reset hepatocellular identity, improve function and ameliorate structural abnormalities. The possibility of correcting the phenotype of severely damaged and malfunctional livers may reveal new therapeutic opportunities for individuals with cirrhosis and advanced liver disease.

Human Hepatocyte Nuclear Factors (HNF1 and LXRb) Regulate CYP7A1 in HIV-Infected Black South African Women with Gallstone Disease: A Preliminary Study

Female sex, high estrogen levels, aging, obesity, and dyslipidemia are some of the risk factors associated with gallstone formation. HIV-infected patients on combination antiretroviral therapy (cART) are more prone to hypercholesterolemia. Bile acid synthesis is initiated by cholesterol 7-alpha hydroxylase (CYP7A1) and regulated by hepatocyte nuclear factors (HNF1α, HNF4α, and LXRb). The aim of this study was to evaluate the expression of HNF1α, HNF4α, LXRb, and miRNAs (HNF4α specific: miR-194-5p and miR-122^*_1) that regulate CYP7A1 transcription in HIV-infected Black South African women on cART and presenting with gallstones relative to HIV-negative patients with gallstone disease. Females (n = 96) presenting with gallstone disease were stratified based on HIV status. The gene expression of CYP7A1, HNF1α, HNF4α, LXRb, miR-194-5p, and miR-122^*_1 was determined using RT-qPCR. Messenger RNA and miRNA levels were reported as fold change expressed as 2^-ΔΔCt (RQ min; RQ max). Fold changes >2 and <0.5 were considered significant. HIV-infected females were older in age (p = 0.0267) and displayed higher low-density lipoprotein cholesterol (LDL-c) (p = 0.0419), CYP7A1 [2.078-fold (RQ min: 1.278; RQ max: 3.381)], LXRb [2.595-fold (RQ min: 2.001; RQ max: 3.000)], and HNF1α [3.428 (RQ min: 1.806; RQ max: 6.507] levels. HNF4α [0.642-fold (RQ min: 0.266; RQ max: 1.55)], miR-194-5p [0.527-fold (RQ min: 0.37; RQ max: 0.752)], and miR-122*_1 [0.595-fold (RQ min: 0.332; RQ max: 1.066)] levels were lower in HIV-infected females. In conclusion, HIV-infected women with gallstone disease displayed higher LDL-c levels and increased bile acid synthesis, which was evidenced by the elevated expression of CYP7A1, HNF1α, and LXRb. This could have been further influenced by cART and aging.

Zymolytic grain extract facilitates the conversion of liver tumor cells to hepatocyte-like cells through hepatocyte nuclear factors

At present, malignant tumors are an urgent global threat to human health. Conversion of cancer cells to normal-like or normal cells will open new therapeutic avenues for eradicating cancer. It has been reported that compounds extracted from grains display biological activities, such as antioxidant, antiviral and antitumor activities. In this study, we identified clear changes in a liver tumor cell line (HepG2) after stimulation with zymolytic grain extract (ZGE) supernatants. The expression levels of hepatocyte nuclear factor 1A (HNF1A), hepatocyte nuclear factor 4A (HNF4A) and forkhead box protein A3 (FOXA3) were significantly increased. Eukaryotic transcriptome analyses revealed that trends in the transcriptional changes for genes were similar in HepG2 cells stimulated with ZGE (zHeps) and the normal hepatocyte cell line L02. Changes in the expression levels of genes involved in drug transport, metabolism and the malignant characteristics of cancer cells in nude mice further indicated that ZGE regulated the expression of HNF1A, HNF4A and FOXA3, which altered the expression of a series of hepatocyte-specific genes. It was also confirmed that zHeps acquired some of the characteristics of hepatocyte-like cells. Our results not only provide new ideas for the treatment of liver tumors but also lay a solid foundation for the application of combination therapy.

Mesoporous Nanoparticles for Diagnosis and Treatment of Liver Cancer in the Era of Precise Medicine

Primary liver cancer is the seventh-most-common cancer worldwide and the fourth-leading cause of cancer mortality. In the current era of precision medicine, the diagnosis and management of liver cancer are full of challenges and prospects. Mesoporous nanoparticles are often designed as specific carriers of drugs and imaging agents because of their special morphology and physical and chemical properties. In recent years, the design of the elemental composition and morphology of mesoporous nanoparticles have greatly improved their drug-loading efficiency, biocompatibility and biodegradability. Especially in the field of primary liver cancer, mesoporous nanoparticles have been modified as highly tumor-specific imaging contrast agents and targeting therapeutic medicine. Various generations of complexes and structures have been determined for the complicated clinical management requirements. In this review, we summarize these advanced mesoporous designs in the different diagnostic and therapeutic fields of liver cancer and discuss the relevant advantages and disadvantages of transforming applications. By comparing the material properties, drug-delivery characteristics and application methods of different kinds of mesoporous materials in liver cancer, we try to help determine the most suitable drug carriers and information media for future clinical trials. We hope to improve the fabrication of biomedical mesoporous nanoparticles and provide direct evidence for specific cancer management.

TMEM43 promotes pancreatic cancer progression by stabilizing PRPF3 and regulating RAP2B/ERK axis

BACKGROUND

Transmembrane protein 43 (TMEM43), a member of the transmembrane protein subfamily, plays a critical role in the initiation and development of cancers. However, little is known concerning the biological function and molecular mechanisms of TMEM43 in pancreatic cancer.

METHODS

In this study, TMEM43 expression levels were analyzed in pancreatic cancer samples compared with control samples. The relationship of TMEM43 expression and disease-free survival (DFS) and overall survival (OS) were assessed in pancreatic cancer patients. In vitro and in vivo assays were performed to explore the function and role of TMEM43 in pancreatic cancer. Coimmunoprecipitation (co-IP) followed by protein mass spectrometry was applied to analyze the molecular mechanisms of TMEM43 in pancreatic cancer.

RESULTS

We demonstrated that TMEM43 expression level is elevated in pancreatic cancer samples compared with control group, and is correlated with poor DFS and OS in pancreatic cancer patients. Knockdown of TMEM43 inhibited pancreatic cancer progression in vitro, decreased the percentage of S phase, and inhibited the tumorigenicity of pancreatic cancer in vivo. Moreover, we demonstrated that TMEM43 promoted pancreatic cancer progression by stabilizing PRPF3 and regulating the RAP2B/ERK axis.

CONCLUSIONS

The present study suggests that TMEM43 contributes to pancreatic cancer progression through the PRPF3/RAP2B/ERK axis, and might be a novel therapeutic target for pancreatic cancer.

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.

Genome-Wide ChIPseq Analysis of AhR, COUP-TF, and HNF4 Enrichment in TCDD-Treated Mouse Liver

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor known for mediating the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related compounds. Although the canonical mechanism of AhR activation involves heterodimerization with the aryl hydrocarbon receptor nuclear translocator, other transcriptional regulators that interact with AhR have been identified. Enrichment analysis of motifs in AhR-bound genomic regions implicated co-operation with COUP transcription factor (COUP-TF) and hepatocyte nuclear factor 4 (HNF4). The present study investigated AhR, HNF4α and COUP-TFII genomic binding and effects on gene expression associated with liver-specific function and cell differentiation in response to TCDD. Hepatic ChIPseq data from male C57BL/6 mice at 2 h after oral gavage with 30 µg/kg TCDD were integrated with bulk RNA-sequencing (RNAseq) time-course (2-72 h) and dose-response (0.01-30 µg/kg) datasets to assess putative AhR, HNF4α and COUP-TFII interactions associated with differential gene expression. Functional enrichment analysis of differentially expressed genes (DEGs) identified differential binding enrichment for AhR, COUP-TFII, and HNF4α to regions within liver-specific genes, suggesting intersections associated with the loss of liver-specific functions and hepatocyte differentiation. Analysis found that the repression of liver-specific, HNF4α target and hepatocyte differentiation genes, involved increased AhR and HNF4α binding with decreased COUP-TFII binding. Collectively, these results suggested TCDD-elicited loss of liver-specific functions and markers of hepatocyte differentiation involved interactions between AhR, COUP-TFII and HNF4α.

Regulation of Liver Regeneration by Hepatocyte O-GlcNAcylation in Mice

BACKGROUND & AIMS

The liver has a unique capacity to regenerate after injury in a highly orchestrated and regulated manner. Here, we report that O-GlcNAcylation, an intracellular post-translational modification regulated by 2 enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), is a critical termination signal for liver regeneration following partial hepatectomy (PHX).

METHODS

We studied liver regeneration after PHX on hepatocyte specific OGT and OGA knockout mice (OGT-KO and OGA-KO), which caused a significant decrease (OGT-KO) and increase (OGA-KO) in hepatic O-GlcNAcylation, respectively.

RESULTS

OGA-KO mice had normal regeneration, but the OGT-KO mice exhibited substantial defects in termination of liver regeneration with increased liver injury, sustained cell proliferation resulting in significant hepatomegaly, hepatic dysplasia, and appearance of small nodules at 28 days after PHX. This was accompanied by a sustained increase in expression of cyclins along with significant induction in pro-inflammatory and pro-fibrotic gene expression in the OGT-KO livers. RNA-sequencing studies revealed inactivation of hepatocyte nuclear 4 alpha (HNF4α), the master regulator of hepatic differentiation and a known termination signal, in OGT-KO mice at 28 days after PHX, which was confirmed by both Western blot and immunohistochemistry analysis. Furthermore, a significant decrease in HNFα target genes was observed in OGT-KO mice, indicating a lack of hepatocyte differentiation following decreased hepatic O-GlcNAcylation. Immunoprecipitation experiments revealed HNF4α is O-GlcNAcylated in normal differentiated hepatocytes.

CONCLUSIONS

These studies show that O-GlcNAcylation plays a critical role in the termination of liver regeneration via regulation of HNF4α in hepatocytes.

Nucleic acid biomarkers to assess graft injury after liver transplantation

Many risk factors and complications impact the success of liver transplantation, such as ischaemia-reperfusion injury, acute rejection, and primary graft dysfunction. Molecular biomarkers have the potential to accurately diagnose, predict, and monitor injury progression or organ failure. There is a critical opportunity for reliable and non-invasive biomarkers to reduce the organ shortage by enabling i) the assessment of donor organ quality, ii) the monitoring of short- and long-term graft function, and iii) the prediction of acute and chronic disease development. To date, no established molecular biomarkers have been used to guide clinical decision-making in transplantation. In this review, we outline the recent advances in cell-free nucleic acid biomarkers for monitoring graft injury in liver transplant recipients. Prior work in this area can be divided into two categories: biomarker discovery and validation studies. Circulating nucleic acids (CNAs) can be found in the extracellular environment pertaining to different biological fluids such as bile, blood, urine, and perfusate. CNAs that are packaged into extracellular vesicles may facilitate intercellular and interorgan communication. Thus, decoding their biological function, cellular origins and molecular composition is imperative for diagnosing causes of graft injury, guiding immunosuppression and improving overall patient survival. Herein, we discuss the most promising molecular biomarkers, their state of development, and the critical aspects of study design in biomarker research for early detection of post-transplant liver injury. Future advances in biomarker studies are expected to personalise post-transplant therapy, leading to improved patient care and outcomes.

Nonalcoholic Fatty Liver Disease (NAFLD): Pathogenesis and Noninvasive Diagnosis

The global prevalence of nonalcoholic fatty liver disease (NAFLD) or metabolic associated fatty liver disease (MAFLD), as it is now known, has gradually increased. NAFLD is a disease with a spectrum of stages ranging from simple fatty liver (steatosis) to a severe form of steatosis, nonalcoholic steatohepatitis (NASH), which could progress to irreversible liver injury (fibrosis) and organ failure, and in some cases hepatocellular carcinoma (HCC). Although a liver biopsy remains the gold standard for accurate detection of this condition, it is unsuitable for clinical screening due to a higher risk of death. There is thus an increased need to find alternative techniques or tools for accurate diagnosis. Early detection for NASH matters for patients because NASH is the marker for severe disease progression. This review summarizes the current noninvasive tools for NAFLD diagnosis and their performance. We also discussed potential and newer alternative tools for diagnosing NAFLD.

Reliable miRNA biomarker quantification in clinical practice - are we there yet?

Blood-borne miRNAs serve as disease diagnostic biomarkers and await clinical validation. Here, we evaluated Cel-miR-39-3p and miRNA16-5p as calibrator for the quantification of 15 miRNAs linked to hepatic impairment. We added defined copy numbers of Cel-miR-39-3p to plasma of healthy controls (N = 5) and patient samples undergoing liver resection (N = 51). The miRNAs were isolated according to SOPs and quantified by RT-qPCR using the 2^-(ΔΔ-CT)-method. Although miRNA16-5p and the spike-in control behaved similar in qPCR assays (R² = 0.8591) the spike-in control suffered from high inter-patient variability (median 7.6-fold) and low recoveries (median 5.6%, 95% CI 1.5-11.8%). Adding Cel-miR-39-3p to blood samples prior to RNA-isolation improved the recoveries (median 105.7%; 95% CI 29.9-219.9%), yet the inter-patient variability remained high (median 7.2-fold). Alike, we observed significant variability in CT-values for miRNA16-5p (range 14.7-fold) thus rendering this internal, blood-borne reference gene unacceptable as comparator. Specifically, 10 out of 15 diagnostic miRNAs failed the criteria R² ≥ 0.8 even though we added a defined copy number of Cel-miR-39-3p. This suggests interference of the spike-in control with individual miRNAs in the assay. Our study highlights current limitations in the quantification of blood-borne miRNAs that is of particularly importance when used for disease diagnostic and therapeutic interventions.

The Role of Protein SUMOylation in Human Hepatocellular Carcinoma: A Potential Target of New Drug Discovery and Development

Simple Summary

The small ubiquitin-like modifier is a highly conserved post-translational modification protein, mainly found in eukaryotes. Recently, studies have shown that SUMOylation promotes the development of liver cancer. This article summarises the recent literature on SUMOylation and Hepatocellular carcinoma (HCC). The mechanism of SUMOs in liver cancer cells was described. It also shows the potential of SUMO as a therapeutic target for liver cancer. At the same time, this article also enumerates the practical application in clinical, developing progress and future direction of HCC in clinical practice.

Abstract

Small ubiquitin-like modifier (SUMO) is a highly conserved post-translational modification protein, mainly found in eukaryotes. They are widely expressed in different tissues, including the liver. As an essential post-translational modification, SUMOylation is involved in many necessary regulations in cells. It plays a vital role in DNA repair, transcription regulation, protein stability and cell cycle progression. Increasing shreds of evidence show that SUMOylation is closely related to Hepatocellular carcinoma (HCC). The high expression of SUMOs in the inflammatory hepatic tissue may lead to the carcinogenesis of HCC. At the same time, SUMOs will upregulate the proliferation and survival of HCC, migration, invasion and metastasis of HCC, tumour microenvironment as well as drug resistance. This study reviewed the role of SUMOylation in liver cancer. In addition, it also discussed natural compounds that modulate SUMO and target SUMO drugs in clinical trials. Considering the critical role of SUMO protein in the occurrence of HCC, the drug regulation of SUMOylation may become a potential target for treatment, prognostic monitoring and adjuvant chemotherapy of HCC.

MiR-192-5p suppresses M1 macrophage polarization via epiregulin (EREG) downregulation in gouty arthritis

Gouty arthritis (GA) is a chronic inflammatory disease characterized by the deposition of monosodium urate (MSU) crystals within joints. MiR-192-5p is shown to be low-expressed in GA patients. However, the potential mechanism involving miR-192-5p in GA remains unclear. In the current study, a significant reduction in miR-192-5p and an increase in epiregulin (EREG) were observed in serum of GA patients, suggesting that miR-192-5p and EREG were involved in the pathogenic process of GA. A mouse GA model was established via 0.5 mg/20 μL MSU crystal administration. To investigate the effect of miR-192-5p on GA, mice were injected with miR-192-5p agomir or NC agomir before modeling. We found that miR-192-5p overexpression induced by miR-192-5p agomir reduced EREG expression, attenuated ankle joint swelling and synovial inflammatory cell infiltration and improved bone erosion in MSU-induced GA mice. MiR-192-5p decreased CD16/32⁺ (M1 marker) macrophages, but increased CD206 (M2 marker) expression in synovium of GA models. In vitro, RAW264.7 macrophages were stimulated with miR-192-5p mimic or NC mimic under IFNγ plus LPS-stimulated M1 polarization condition. MiR-192-5p reduced the release of inflammatory cytokines TNF-α and IL-1β, decreased iNOS expression, and inhibited CD16/32 expression, indicating the blockade of M1 macrophage activation. Luciferase reporter system revealed the target interaction between miR-192-5p and EREG. Further rescue experiments demonstrated that EREG overexpression partly reversed the inhibitory role of miR-192-5p on M1 macrophage polarization manifested by elevated iNOS and CD16/32 levels. Collectively, miR-192-5p ameliorates inflammatory response in GA by inhibiting M1 macrophage activation via inhibiting EREG protein.

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.

LncRNACASC9 promotes proliferation, metastasis, and cell cycle inovarian carcinoma cells through cyclinG1/TP53/MMP7 signaling

Ovarian cancer (OC) brings about serious physical and psychological burden for female patients. LncRNA CASC9 has been reported to be intimately linked with the occurrence and development of several tumors. However, the biological role of lncRNA CASC9 in OC still lacks sufficient evidence. The expressions of CASC9 and miR-488-3p in OC cell lines and xenograft mice were detected by qRT-PCR assay. Cell Counting Kit-8 (CCK-8) assay was used to assess cell inhibition rate and cell proliferation in OVCAR-3 and OVCAR-3/DDP cells. Wound healing assay and transwell assay were performed to evaluate the capacity of migration and invasion, respectively. In addition, cell apoptosis was measured by TUNEL assay and cell cycle was assessed by flow cytometric analysis. Moreover, western blotting was carried out to detect the cyclinG1 (CCNG1)/TP53/MMP7 signaling and apoptosis-related proteins. Furthermore, luciferase reporter assay was performed to verify the combination of CASC9 with CCNG1 and miR-488-3p. The results of our study revealed that CASC9 expression was upregulated while miR-488-3p and CCNG1 expression was downregulated in OC cells with significant higher TP53 and MMP7 protein levels compared with normal ovarian surface epithelial cells. Additionally, luciferase reporter assay confirmed CASC9 bond to miR-488-3p/CCNG1. CASC9 silencing inhibited cell proliferation, migration, and invasion whereas promoted cell inhibition rate and apoptosis in vitro and in vivo. However, CASC9 overexpression showed the opposite effects. In summary, LncRNA CASC9 played a regulative role in ovarian carcinoma by cyclinG1/TP53/MMP7 signaling via binding to miR-488-3p in vivo and in vitro.

FAT10 promotes hepatocellular carcinoma (HCC) carcinogenesis by mediating P53 degradation and acts as a prognostic indicator of HCC

Background

With the advancement of hepatocellular carcinoma (HCC) treatment technology, the treatment options for HCC patients have increased. However, due to high heterogeneity, among other reasons, the five-year survival rate of patients is still very low. Currently, gene expression prognostic models can suggest more appropriate strategies for the treatment of HCC. This study investigates the role of FAT10 in hepatocarcinogenesis and its underlying mechanism.

Methods

The expression of FAT10 was detected by immunohistochemical method using tissue arrays containing 4 specimens of patients with digestive cancer. The expression of FAT10 was determined by a tissue microarray which included 286 pairs of HCC samples and corresponding normal mucosae and was further confirmed by real-time polymerase chain reaction (PCR) and western blot. The Kaplan-Meier survival curve was used to determine the correlation of FAT10 expression with patients' recurrence and overall survival (OS) rate. In vivo, liver fibrosis, cirrhosis, and HCC models were established to assess the FAT10 expression. Moreover, FAT10 over-expressing cell lines were used to determine the molecular mechanism underlying the FAT10-induced cell proliferation and hepatocarcinogenesis by reporter gene measure, real-time PCR, and western blot. Based on TCGA database, signal pathways associated with FAT10 and HCC invasion and metastasis were analyzed by KEGG enrichment analyze.

Results

Overexpression of FAT10 in HCC was observed in this study compared with its expression in other digestive tumors. Clinicopathological analysis revealed that FAT10 expression levels were closely associated with tumor diameters and poor prognosis of HCC. This study also confirmed through in vivo experiments that the expression of FAT10 in liver fibrosis, cirrhosis, and HCC gradually increases. Further study revealed that forced FAT10 expression enhanced the growth ability of HCC cells and mediated the degradation of the critical anti-cancer protein p53, which led to carcinogenesis. Finally, 9 signal pathways related to HCC metastasis were obtained through bioinformatics analysis.

Conclusions

FAT10 may act as a proto-oncogene that facilitates HCC carcinogenesis by mediating p53 degradation, and the expression of FAT10 is negatively correlated with the prognosis of HCC patients. FAT10 is expected to become a potential combined target and prognostic warning marker for HCC treatment.

MicroRNA-192-5p inhibits migration of triple negative breast cancer cells and directly regulates Rho GTPase activating protein 19

Among the different breast cancer subtypes, triple-negative breast cancer (TNBC) is associated with a poor prognosis, low survival rates, and high expression of histone deacetylases. Treatment with histone deacetylase inhibitor trichostatin A (TSA) leads to an increased expression of potential tumor-suppressive miRNAs. Characterization of these miRNAs can help to find new molecular targets for treatment of TNBC. We identified differentially expressed miRNAs by microarray analyses after treatment with TSA in the TNBC cell lines HCC38, HCC1395, and HCC1935. The gene locus of hsa-miRNA-192-5p (miR-192) and hsa-miR-194-2 (miR-194-2) with its host gene, long noncoding RNA miR-194-2HG, has been linked to inhibition of migration in different tumor types. Therefore, we examined tumor-relevant functional effects using WST-1-based proliferation, capsase-3/7-based apoptosis, and trans-well migration assays after transfection with miRNA mimics or specific siRNAs. We demonstrated the tumor-suppressive capacity of miR-192 in TNBC cells, which was exerted through inhibition of proliferation, induction of apoptosis, and reduction of migration. Gene expression and bioinformatics analyses of TNBC cell lines transfected with miR-192 mimics, identified a number of genes involved in migration including the Rho GTPase Activating Protein ARHGAP19. Through RNA immunoprecipitation we demonstrated the direct binding of miR-192 and ARHGAP19. Downregulation of ARHGAP19 expression by either miR-192 or siRNA inhibited migration of TNBC cells significantly. Our findings demonstrate that overexpression of epigenetically deregulated miR-192 decreases proliferation, promotes apoptosis, and inhibits migration of TNBC cell lines.

Hepatocyte-Specific Hepatocyte Nuclear Factor 4 Alpha (HNF4) Deletion Decreases Resting Energy Expenditure by Disrupting Lipid and Carbohydrate Homeostasis

Hepatocyte nuclear factor 4 alpha (HNF4) is required for hepatocyte differentiation and regulates expression of genes involved in lipid and carbohydrate metabolism including those that control VLDL secretion and gluconeogenesis. Whereas previous studies have focused on specific genes regulated by HNF4 in metabolism, its overall role in whole-body energy utilization has not been studied. In this study, we used indirect calorimetry to determine the effect of hepatocyte-specific HNF4 deletion (HNF4-KO) in mice on whole-body energy expenditure (EE) and substrate utilization in fed, fasted, and high-fat diet (HFD) conditions. HNF4-KO had reduced resting EE during fed conditions and higher rates of carbohydrate oxidation with fasting. HNF4-KO mice exhibited decreased body mass caused by fat mass depletion despite no change in energy intake and evidence of positive energy balance. HNF4-KO mice were able to upregulate lipid oxidation during HFD, suggesting that their metabolic flexibility was intact. However, only hepatocyte-specific HNF4-KO mice exhibited significant reduction in basal metabolic rate and spontaneous activity during HFD. Consistent with previous studies, hepatic gene expression in HNF4-KO supports decreased gluconeogenesis and decreased VLDL export and hepatic -oxidation in HNF4-KO livers across all feeding conditions. Together, our data suggest that deletion of hepatic HNF4 increases dependence on dietary carbohydrates and endogenous lipids for energy during fed and fasted conditions by inhibiting hepatic gluconeogenesis, hepatic lipid export, and intestinal lipid absorption resulting in decreased whole-body energy expenditure. These data clarify the role of hepatic HNF4 on systemic metabolism and energy homeostasis.

Long non-coding RNA LINC01215 promotes epithelial-mesenchymal transition and lymph node metastasis in epithelial ovarian cancer through RUNX3 promoter methylation

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The study first reports the regulation of LINC01215 on methylation of RUNX3 promoter.

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LINC01215 is highly expressed while RUNX3 is reciprocal in EOC.

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LINC01215 overexpression promotes methylation of RUNX3 and reduces its expression.

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LINC01215 silencing suppresses LNM and EMT of EOC.

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This study may provide a new therapeutic target for EOC.

Epithelial ovarian cancer (EOC) still remains the most lethal gynaecological malignancy in women, despite the recent progress in the management, including surgery and chemotherapy. According to the microarray data of the GSE18520 and GSE54388 datasets, LINC01215 was identified as an upregulated long noncoding RNA (lncRNA) in EOC. Therefore, this study aimed to figure out the involvement of LINC01215 in the progression of EOC. RT-qPCR was conducted to select the EOC cell line with the highest expression of LINC01215. Methylation of RUNX3 was then examined in EOC cells by MS-PCR. Furthermore, the interaction between LINC01215 and methylation-related proteins was revealed according to the results of RIP and RNA pull down assays. Subsequently, the involvement of LINC01215 and RUNX3 in regulating biological behaviors of EOC cells was investigated. Finally, the effects of the ectopic expression of LINC01215 and RUNX3 on the tumor formation and lymph node metastasis (LNM) of EOC cells were assessed in the xenograft tumors of nude mice. Overexpressing LINC01215 contributed to downregulated levels of RUNX3, as demonstrated by the recruitment of methylation-related proteins. Silencing of LINC01215 elevated the expression of RUNX3, thus suppressing cell proliferation, migration, invasion and EMT and decreasing the expressions of MMP-2, MMP-9 and Vimentin, but increased the expression of E-cadherin. The tumor growth and LNM were suppressed by downregulated levels of LINC01215 through inducing the expression of RUNX3. Collectively, the down-regulating LINC01215 could upregulate the expression of RUNX3 by promoting its methylation, thus suppressing EOC cell proliferation, migration and invasion, EMT, tumor growth and LNM.

Continual proteomic divergence of HepG2 cells as a consequence of long-term spheroid culture

Three-dimensional models are considered a powerful tool for improving the concordance between in vitro and in vivo phenotypes. However, the duration of spheroid culture may influence the degree of correlation between these counterparts. When using immortalised cell lines as model systems, the assumption for consistency and reproducibility is often made without adequate characterization or validation. It is therefore essential to define the biology of each spheroid model by investigating proteomic dynamics, which may be altered relative to culture duration. As an example, we assessed the influence of culture duration on the relative proteome abundance of HepG2 cells cultured as spheroids, which are routinely used to model aspects of the liver. Quantitative proteomic profiling of whole cell lysates labelled with tandem-mass tags was conducted using liquid chromatography-tandem mass spectrometry (LC-MS/MS). In excess of 4800 proteins were confidently identified, which were shared across three consecutive time points over 28 days. The HepG2 spheroid proteome was divergent from the monolayer proteome after 14 days in culture and continued to change over the successive culture time points. Proteins representing the recognised core hepatic proteome, cell junction, extracellular matrix, and cell adhesion proteins were found to be continually modulated.

Assembly and Function of a Bioengineered Human Liver for Transplantation Generated Solely from Induced Pluripotent Stem Cells

The availability of an autologous transplantable auxiliary liver would dramatically affect the treatment of liver disease. Assembly and function in vivo of a bioengineered human liver derived from induced pluripotent stem cells (iPSCs) has not been previously described. By improving methods for liver decellularization, recellularization, and differentiation of different liver cellular lineages of human iPSCs in an organ-like environment, we generated functional engineered human mini livers and performed transplantation in a rat model. Whereas previous studies recellularized liver scaffolds largely with rodent hepatocytes, we repopulated not only the parenchyma with human iPSC-hepatocytes but also the vascular system with human iPS-endothelial cells, and the bile duct network with human iPSC-biliary epithelial cells. The regenerated human iPSC-derived mini liver containing multiple cell types was tested in vivo and remained functional for 4 days after auxiliary liver transplantation in immunocompromised, engineered (IL2rg^-/-) rats.

LINC01419-mediated epigenetic silencing of ZIC1 promotes metastasis in hepatocellular carcinoma through the PI3K/Akt signaling pathway

Hepatocellular carcinoma (HCC) is a rapidly growing tumor characterized by a high potential for vascular invasion and metastasis. The purpose of our study is to explore the regulation mechanism of long noncoding RNA (lncRNA) LINC01419 on cell-cycle distribution and metastasis in hepatocellular carcinoma (HCC) by regulating zinc finger of the cerebellum (ZIC1) through PI3K/Akt signaling pathway. Bioinformatics analysis and dual-luciferase reporter assay were used to analyze LINC01419 and related genes in HCC, and their expression in HCC tissues and adjacent normal tissues were determined by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot. Then, HCC cell lines were subjected to the construction of LINC01419/ZIC1 overexpression/knockdown cells utilizing lentiviral vectors. RIP and ChIP assays were applied to identify the LINC01419-binding protein. BSP and MSP assays were used to determine gene methylation. According to the results, LINC01419 was highly expressed in HCC tissues and cells, while ZIC1 was poorly expressed. LINC01419 targeted and downregulated ZIC1 expression. Furthermore, LINC01419 increased the methylation of ZIC1 promoter and repressed ZIC1 expression. PI3K/Akt signaling pathway was activated by LINC01419 overexpression and ZIC1 knockdown, under which conditions, the HCC cell self-renewal and proliferation were promoted while cell apoptosis was attenuated, accompanied by accelerated formation and metastasis of xenografted tumors in mice. In conclusion, LINC01419 enhances the methylation of ZIC1 promoter, inhibits ZIC1 expression, and activates the PI3K/Akt signaling pathway, thereby enhancing the malignant phenotypes of HCC cells in vitro as well as tumor formation and metastasis in vivo.

MicroRNAs as regulators, biomarkers and therapeutic targets in liver diseases

MicroRNAs (miRNAs) are small, non-coding RNAs that post-transcriptionally regulate gene expression by binding to specific mRNA targets and promoting their degradation and/or translational inhibition. miRNAs regulate both physiological and pathological liver functions. Altered expression of miRNAs is associated with liver metabolism dysregulation, liver injury, liver fibrosis and tumour development, making miRNAs attractive therapeutic strategies for the diagnosis and treatment of liver diseases. Here, we review recent advances regarding the regulation and function of miRNAs in liver diseases with a major focus on miRNAs that are specifically expressed or enriched in hepatocytes (miR-122, miR-194/192), neutrophils (miR-223), hepatic stellate cells (miR-29), immune cells (miR-155) and in circulation (miR-21). The functions and target genes of these miRNAs are emphasised in alcohol-associated liver disease, non-alcoholic fatty liver disease, drug-induced liver injury, viral hepatitis and hepatocellular carcinoma, as well liver fibrosis and liver failure. We touch on the roles of miRNAs in intercellular communication between hepatocytes and other types of cells via extracellular vesicles in the pathogenesis of liver diseases. We provide perspective on the application of miRNAs as biomarkers for early diagnosis, prognosis and assessment of liver diseases and discuss the challenges in miRNA-based therapy for liver diseases. Further investigation of miRNAs in the liver will help us better understand the pathogeneses of liver diseases and may identify biomarkers and therapeutic targets for liver diseases in the future.

Identification of miRNAs that regulate human CYP2B6 expression

Human hepatic cytochrome P450 2B6 (CYP2B6) expressed is responsible for the metabolism of many drugs, such as cyclophosphamide, ifosfamid, and efavirenz. In the present study, the correlation between CYP2B6 mRNA and protein levels in human liver samples was found to be moderate, indicating a contribution of posttranscriptional regulation of CYP2B6. Thus, we examined the role of microRNAs (miRNAs) in the regulation of CYP2B6. We established two kinds of HEK293 cell lines stably expressing CYP2B6, including or excluding the full-length 3'-untranslated region (3'-UTR) (HEK/2B6+UTR and HEK/2B6 cells, respectively). We tested 14 miRNAs that were predicted to bind to the 3'-UTR of CYP2B6 and found that the overexpression of miR-145, miR-194, miR-222, and miR-378 decreased the CYP2B6 protein level and activity in HEK/2B6+UTR but not in HEK/2B6 cells. These results suggested that miR-145, miR-194, miR-222, and miR-378 negatively regulate CYP2B6 expression by binding to the 3'-UTR. A negative correlation was not observed between the translational efficiency of CYP2B6 and the expression level of miR-145, miR-194, miR-222, or miR-378. This is due to the contribution of multiple miRNAs to CYP2B6 regulation. In conclusion, this study demonstrated that human CYP2B6 is posttranscriptionally regulated by miR-145, miR-194, miR-222, and miR-378.

MiR-192-5p regulates the proliferation and apoptosis of cholangiocarcinoma cells by activating MEK/ERK pathway

OBJECTIVE

Cholangiocarcinoma (CCA) is the second most common liver cancer, characterized by late diagnosis and fatal outcome. Although miR-192-5p has been shown to have a vital role in various cancers, its role in CCA is unknown. Here, we investigated the role of miR-192-5p in CCA cell proliferation and apoptosis, and elucidated its potential mechanism of action.

METHODS

The miR-192-5p expression in CCA tissues and cell lines was detected by real-time quantitative reverse transcription-polymerase chain reaction. Cell proliferation was analyzed using the cell counting Kit-8 and 5-bromodeoxyuridine staining assays, while apoptosis was examined by flow cytometry and the terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick-end labeling assay. Western blot analysis was used to measure the expression of cell proliferation and apoptosis-related proteins, as well as MEK/ERK signaling pathway-related proteins.

RESULTS

MiR-192-5p was highly expressed in CCA tissues and cell lines. Overexpression of miR-192-5p significantly promoted CCA proliferation, and inhibited apoptosis. The MEK inhibitor, PD98059, reversed these miR-192-5p-induced effects on MEK/ERK signaling-associated protein expression, proliferation promotion, and apoptosis inhibition in TFK-1 cells.

CONCLUSION

MiR-192-5p promotes proliferation and suppressed apoptosis of CCA cells via the MEK/ERK pathway, which may be a potential therapeutic strategy for CCA treatment.

Non-coding RNA crosstalk with nuclear receptors in liver disease

The dysregulation of nuclear receptors (NRs) underlies the pathogenesis of a variety of liver disorders. Non-coding RNAs (ncRNAs) are defined as RNA molecules transcribed from DNA but not translated into proteins. MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are two types of ncRNAs that have been extensively studied for regulating gene expression during diverse cellular processes. NRs as therapeutic targets in liver disease have been exemplified by the successful application of their pharmacological ligands in clinics. MiRNA-based reagents or drugs are emerging as flagship products in clinical trials. Advancing our understanding of the crosstalk between NRs and ncRNAs is critical to the development of diagnostic and therapeutic strategies. This review summarizes recent findings on the reciprocal regulation between NRs and ncRNAs (mainly on miRNAs and lncRNAs) and their implication in liver pathophysiology, which might be informative to the translational medicine of targeting NRs and ncRNAs in liver disease.

Regulation of ARHGAP19 in the endometrial epithelium: a possible role in the establishment of uterine receptivity

BACKGROUND

The establishment of uterine receptivity is essential for embryo implantation initiation and involves a significant morphological transformation in the endometrial epithelial cells (EECs). The remodeling of junctional complexes and membrane-associated cytoskeleton is crucial for epithelial transformation. However, little is known about how this process is regulated in EECs during the receptive phase. ARHGAP19 is a Rho GTPase-activating protein that participates in various cytoskeletal-related events, including epithelial morphogenesis. Here, we investigated the role of ARHGAP19 in endometrial epithelial transformation during the establishment of uterine receptivity. The upstream regulator of ARHGAP19 was also investigated.

METHODS

ARHGAP19 expression was examined in mouse uteri during early pregnancy and in human EEC lines. The role of ARHGAP19 was investigated by manipulating its expression in EECs. The effect of ARHGAP19 on junctional proteins in EECs was examined by western blotting and immunofluorescence. The effect of ARHGAP19 on microvilli was examined by scanning electron microscopy. The upstream microRNA (miRNA) was predicted using online databases and validated by the dual-luciferase assay. The in vivo and in vitro effect of miRNA on endogenous ARHGAP19 was examined by uterine injection of miRNA agomirs and transfection of miRNA mimics or inhibitors.

RESULTS

ARHGAP19 was upregulated in the receptive mouse uteri and human EECs. Overexpression of ARHGAP19 in non-receptive EECs downregulated the expression of junctional proteins and resulted in their redistribution. Meanwhile, upregulating ARHGAP19 reorganized the cytoskeletal structure of EECs, leading to a decline of microvilli and changes in cell configuration. These changes weakened epithelial cell polarity and promoted the transition of non-receptive EECs to a receptive phenotype. Besides, miR-192-5p, a miRNA that plays a key role in maintaining epithelial properties, was validated as an upstream regulator of ARHGAP19.

CONCLUSION

These results suggested that ARHGAP19 may contribute to the transition of EECs from a non-receptive to a receptive state by regulating the remodeling of junctional proteins and membrane-associated cytoskeleton.

Hepatocyte nuclear factor 4α and cancer-related cell signaling pathways: a promising insight into cancer treatment

Hepatocyte nuclear factor 4α (HNF4α), a member of the nuclear receptor superfamily, is described as a protein that binds to the promoters of specific genes. It controls the expression of functional genes and is also involved in the regulation of numerous cellular processes. A large number of studies have demonstrated that HNF4α is involved in many human malignancies. Abnormal expression of HNF4α is emerging as a critical factor in cancer cell proliferation, apoptosis, invasion, dedifferentiation, and metastasis. In this review, we present emerging insights into the roles of HNF4α in the occurrence, progression, and treatment of cancer; reveal various mechanisms of HNF4α in cancer (e.g., the Wnt/β-catenin, nuclear factor-κB, signal transducer and activator of transcription 3, and transforming growth factor β signaling pathways); and highlight potential clinical uses of HNF4α as a biomarker and therapeutic target for cancer.

Bovine hepatic miRNAome profiling and differential miRNA expression analyses between beef steers with divergent feed efficiency phenotypes

MicroRNAs (miRNAs) are small RNA molecules involved in regulation of multiple biological processes through modulating expression of their target genes. Here we employed RNAseq to profile liver tissue miRNAome of 60 steers from Angus, Charolais, and Kinsella Composite (KC) populations. Of these animals, 36 animals (n = 12 for each breed) were utilized to identify differentially expressed (DE) miRNAs between animals with high (n = 6) or low (n = 6) phenotypic values of residual feed intake (RFI), a common measurement of feed efficiency. At a threshold of fold-change > 1.5 and P-value < 0.05, we detected 12 (7 up- and 5 downregulated in low-RFI animals), 18 (12 up- and 6 downregulated), and 13 (8 up- and 5 downregulated) DE miRNAs for Angus, Charolais, and KC steers, respectively. Most of the DE miRNAs were breed specific, with bta-miR-449a and bta-miR-AB-2 being differentially expressed in all three breeds. The predicted target genes of the identified DE miRNA are mainly involved in cell cycle, cell death and survival, cell signaling, cellular growth and proliferation, protein trafficking, cell morphology, cell-to-cell signaling and interaction, cellular development, molecular transport, post-translational modification, as well as nutrient metabolism (lipids, carbohydrates, protein and amino acid). Our results provide insights into the bovine hepatic miRNAome and their potential roles in molecular regulation of RFI in beef cattle.

Genetic and epigenetic factors determining NAFLD risk

BACKGROUND

Hepatic steatosis is a common chronic liver disease that can progress into more severe stages of NAFLD or promote the development of life-threatening secondary diseases for some of those affected. These include the liver itself (nonalcoholic steatohepatitis or NASH; fibrosis and cirrhosis, and hepatocellular carcinoma) or other organs such as the vessels and the heart (cardiovascular disease) or the islets of Langerhans (type 2 diabetes). In addition to elevated caloric intake and a sedentary lifestyle, genetic and epigenetic predisposition contribute to the development of NAFLD and the secondary diseases.

SCOPE OF REVIEW

We present data from genome-wide association studies (GWAS) and functional studies in rodents which describe polymorphisms identified in genes relevant for the disease as well as changes caused by altered DNA methylation and gene regulation via specific miRNAs. The review also provides information on the current status of the use of genetic and epigenetic factors as risk markers.

MAJOR CONCLUSION

With our overview we provide an insight into the genetic and epigenetic landscape of NAFLD and argue about the applicability of currently defined risk scores for risk stratification and conclude that further efforts are needed to make the scores more usable and meaningful.

Control of Cell Identity by the Nuclear Receptor HNF4 in Organ Pathophysiology

Hepatocyte Nuclear Factor 4 (HNF4) is a transcription factor (TF) belonging to the nuclear receptor family whose expression and activities are restricted to a limited number of organs including the liver and gastrointestinal tract. In this review, we present robust evidence pointing to HNF4 as a master regulator of cellular differentiation during development and a safekeeper of acquired cell identity in adult organs. Importantly, we discuss that transient loss of HNF4 may represent a protective mechanism upon acute organ injury, while prolonged impairment of HNF4 activities could contribute to organ dysfunction. In this context, we describe in detail mechanisms involved in the pathophysiological control of cell identity by HNF4, including how HNF4 works as part of cell-specific TF networks and how its expression/activities are disrupted in injured organs.

Synergistic regulation of hepatic Fsp27b expression by HNF4α and CREBH

The CIDE (cell death-inducing DFF45-like effector) family composed of CIDEA, CIDEB, CIDEC/FSP27 (fat-specific protein 27), has a critical role in growth of lipid droplets. Of these, CIDEB and CIDEC2/FSP27B are abundant in the liver, and the steatotic livers, respectively. Hepatocyte nuclear factor 4α (HNF4α) has an important role in lipid homeostasis because liver-specific HNF4α-null mice (Hnf4a^ΔHep mice) exhibit hepatosteatosis. We investigated whether HNF4α directly regulates expression of CIDE family genes. Expression of Cideb and Fsp27b was largely decreased in Hnf4a^ΔHep mice, while expression of Cidea was increased. Similar results were observed only in CIDEC2, the human orthologue of the Fsp27b, in human hepatoma cell lines in which HNF4α expression was knocked down. Conversely, overexpression of HNF4α strongly induced CIDEC2 expression in hepatoma cell lines. Furthermore, HNF4α transactivated Fsp27b by direct binding to an HNF4α response element in the Fsp27b promoter. In addition, Fsp27b is known to be transactivated by CREBH that is regulated by HNF4α, and expression of CREBH was induced by HNF4α in human hepatoma cells. Co-transfection of HNF4α and CREBH resulted in synergistic transactivation and induction of Fsp27b compared to that of HNF4α or CREBH alone. These results suggest that HNF4α, in conjunction with CREBH, plays an important role in regulation of Fsp27b expression.

DDP-resistant ovarian cancer cells-derived exosomal microRNA-30a-5p reduces the resistance of ovarian cancer cells to DDP

Exosomes carrying microRNAs (miRNAs) have been demonstrated to play critical roles in the regulation of development, growth and metastasis of cancer. Bioinformatic predictions identified differentially expressed SRY-box 9 (SOX9) in OC, and the regulatory miRNA miR-139-5p. Here, we aim to evaluate the function of exosomal miR-139-5p in the sensitivity of ovarian cancer (OC) cells to cis-diamminedichloroplatinum(II) (DDP). Expression pattern of miR-139-5p and SOX9 in ovarian cancer cells (SKOV3) and DDP-resistant cells (SKOV3/DDP) was identified using reverse transcription quantitative polymerase chain reaction and western blot analysis. The relationship between miR-139-5p and SOX9 was validated using a dual-luciferase reporter assay. SKOV3/DDP cell line was developed and introduced with miR-30a-5p mimic to analyse the effects of miR-30a-5p on resistance to DDP. The in vitro and in vivo effects of exosomal miR-30a-5p on resistance of SKOV3 cells to DDP were assessed in a co-culture system of exosomes and OC cells as well as in tumour-bearing nude mice. High expression of SOX9 and low expression of miR-30-5p were witnessed in OC. Furthermore, miR-30-5p, a downregulated miRNA in SKOV3/DDP cells, increased the rate of cell apoptosis and enhanced the sensitivity of SKOV3/DDP cells to DDP by targeting SOX9. Moreover, exosomes carrying miR-30a-5p were identified to sensitize SKOV3/DDP cells to DDP both in vitro and in vivo. These data together supported an important conclusion that DDP-resistant OC cell-derived exosomal miR-30a-5p enhanced cellular sensitivity to DDP, highlighting a potential strategy to overcome drug resistance.

Specific circulating microRNAs during hepatitis E infection can serve as indicator for chronic hepatitis E

Hepatitis E virus (HEV) genotypes 3 and 4 (HEV-3, HEV-4) infections are an emerging public health issue in industrialized countries. HEV-3 and −4 are usually self-limiting but can progress to chronic hepatitis E in immunocompromised individuals. The molecular mechanisms involved in persistent infections are poorly understood. Micro RNAs (miRNAs) can regulate viral pathogenesis and can serve as novel disease biomarkers. We aimed to explore the modulation of serum miRNAs in patients with acute (AHE) and chronic (CHE) hepatitis E. Both AHE- and CHE-patients exhibited high viral loads (median 3.23E + 05 IU/mL and 2.11E + 06 IU/mL, respectively) with HEV-3c being the predominant HEV-genotype. Expression analysis of liver-specific serum miRNAs was performed using real-time PCR. miR-99a-5p, miR-122-5p, and miR-125b-5p were upregulated in AHE (4.70–5.28 fold) and CHE patients (2.28–6.34 fold), compared to HEV-negative controls. Notably, miR-192-5p was increased 2.57 fold while miR-125b-5p was decreased 0.35 fold in CHE but not in AHE patients. Furthermore, decreased miR-122-5p expression significantly correlates with reduced liver transaminases in CHE patients. To our knowledge, this marks the first investigation concerning the regulation of circulating liver-specific miRNAs in acute and chronic HEV infections. We found that miR-125b-5p, miR-192-5p, and miR-99a-5p may prove useful in the diagnosis of chronic hepatitis E.

Global microRNA profiling in human urinary exosomes reveals novel disease biomarkers and cellular pathways for autosomal dominant polycystic kidney disease

MicroRNAs (miRNAs) play an important role in regulating gene expression in health and disease but their role in modifying disease expression in Autosomal Dominant Polycystic Kidney Disease (ADPKD) remains uncertain. Here, we profiled human urinary exosome miRNA by global small RNA-sequencing in an initial discovery cohort of seven patients with ADPKD with early disease (eGFR over 60ml/min/1.73m²), nine with late disease (eGFR under 60ml/min/1.73m²), and compared their differential expression with six age and sex matched healthy controls. Two kidney-enriched candidate miRNA families were identified (miR-192/miR-194-2 and miR-30) and selected for confirmatory testing in a 60 patient validation cohort by quantitative polymerase chain reaction. We confirmed that miR-192-5p, miR-194-5p, miR-30a-5p, miR-30d-5p and miR-30e-5p were significantly downregulated in patient urine exosomes, in murine Pkd1 cystic kidneys and in human PKD1 cystic kidney tissue. All five miRNAs showed significant correlations with baseline eGFR and ultrasound-determined mean kidney length and improved the diagnostic performance (area under the curve) of mean kidney length for the rate of disease progression. Finally, inverse correlations of these two miRNA families with increased expression in their predicted target genes in patient PKD1 cystic tissue identified dysregulated pathways and transcriptional networks including novel interactions between miR-194-5p and two potentially relevant candidate genes, PIK3R1 and ANO1. Thus, our results identify a subset of urinary exosomal miRNAs that could serve as novel biomarkers of disease progression and suggest new therapeutic targets in ADPKD.

miR-194 suppresses epithelial-mesenchymal transition of retinal pigment epithelial cells by directly targeting ZEB1

Background

Epithelial-mesenchymal transition (EMT) of the retinal pigment epithelial (RPE) cells is a critical step in the pathogenesis of proliferative vitreoretinopathy (PVR). Some microRNAs (miRNAs) participate in regulating RPE cell EMT as post-transcriptional regulators. However, the function of miR-194 in RPE cell EMT remains elusive. Here, the role of miR-194 in PVR was investigated.

Methods

Retinal layers were obtained using laser capture microdissection (LCM). Gene expression at the mRNA and protein level in the tissues and cells was examined using quantitative reverse transcription (RT)-polymerase chain reaction and Western blotting, respectively. The related protein expression was observed by immunostaining. The effect of miR-194 on RPE cell EMT was examined by gel contraction, wound healing, and cell migration assays. RNAseq was performed in ARPE-19 with transfection of pSuper-scramble and pSuper-miR-194. The target gene of miR-194 was identified and confirmed via bioinformatics analysis and dual-luciferase reporter assay. ARPE-19 (adult retinal pigment epithelium-19) cells were treated with transforming growth factor (TGF)-β1 in the same fashion as the in vitro RPE cell EMT model. A PVR rat model was prepared by intravitreous injection of ARPE-19 cells with plasma-rich platelets.

Results

miR-194 was preferentially expressed in the RPE cell layer compared with the outer nuclear layer (ONL), inner nuclear layer (INL), and ganglion cell layer in rat retina. RNAseq analysis indicated that miR-194 overexpression was involved in RPE cell processes, including phagocytosis, ECM-receptor interaction, cell adhesion molecules, and focal adhesion. miR-194 overexpression significantly inhibited the TGF-β1-induced EMT phenotype of RPE cells in vitro. Zinc finger E-box binding homeobox 1 (ZEB1), a key transcription factor in EMT, was confirmed as the direct functional target of miR-194. Knockdown of ZEB1 attenuated TGF-β1-induced α-smooth muscle actin expression in ARPE-19 cells, and overexpression of miR-194 could significantly reduce the expression of some genes which were up-regulated by ZEB1. Exogenous miR-194 administration in vivo effectively suppressed PVR in the rat model, both functionally and structurally.

Conclusions

Our findings demonstrate for the first time that miR-194 suppresses RPE cell EMT by functionally targeting ZEB1. The clinical application of miR-194 in patients with PVR merits further investigation.

Silencing microRNA-221/222 cluster suppresses glioblastoma angiogenesis by suppressor of cytokine signaling-3-dependent JAK/STAT pathway

Angiogenesis is a major pathologic characteristic of glioblastoma, which is one aggressive primary brain tumor. MicroRNA-221/222 (miR-221/222) cluster has been previously reported to function importantly in malignant glioma biological process. The current study aims at evaluating the effects of miR-221/222 cluster on angiogenesis of glioblastoma cells. Microarray data were analyzed to select glioblastoma-associated differentially expressed genes, and dual-luciferase reporter assay was performed to assess targeting correlation between miR-221/222 cluster and suppressor of cytokine signaling-3 (SOCS3). Subsequently, the expression patterns of miR-221 and miR-222 in glioblastoma cells were identified. miR-221 and miR-222 were overexpressed or silenced in glioblastoma cells to identify the effect of miR-221/222 cluster in cell invasion, migration, proliferation, and angiogenesis. To define downstream pathway of miR-221/222 cluster or SOCS3 in glioblastoma, levels of Janus kinase (JAK)/signal transducers and activators of transcription (STAT) pathway-related proteins were assessed. Additionally, the functions of miR-221/222 on glioblastoma cell angiogenesis were measured in vivo with microvessel density assayed. miR-221 and miR-222 were expressed at a high level and SOCS3 was at a low level in glioblastoma. Downregulation of the miR-221/222 cluster diminished the invasion, migration, proliferation, and angiogenesis with reduced protein levels of matrix metalloproteinase-2 (MMP-2), MMP-9, and vascular endothelial growth factor in glioblastoma cells. Also, silencing miR-221/222 cluster reduced p-JAK2/JAK2 and p-STAT3/STAT3. Consistently, the inhibitory role of silencing miR-221/222 cluster on tumorigenesis of glioblastoma cells was confirmed in vivo. Collectively, the inhibition of miR-221/222 cluster could attenuate the glioblastoma angiogenesis through inactivation of the JAK/STAT pathway by upregulating SOCS3.

MicroRNA-101 Protects Against Cardiac Remodeling Following Myocardial Infarction via Downregulation of Runt-Related Transcription Factor 1

Background

Myocardial infarction (MI) generally leads to heart failure and sudden death. The hearts of people with MI undergo remodeling with the features of expanded myocardial infarct size and dilated left ventricle. Many microRNAs (miRs) have been revealed to be involved in the remodeling process; however, the participation of miR‐101 remains unknown. Therefore, this study aims to find out the regulatory mechanism of miR‐101 in MI‐induced cardiac remodeling.

Methods and Results

Microarray data analysis was conducted to screen differentially expressed genes in MI. The rat model of MI was established by left coronary artery ligation. In addition, the relationship between miR‐101 and runt‐related transcription factor 1 (RUNX1) was identified using dual luciferase reporter assay. After that, the rats injected with lentiviral vector expressing miR‐101 mimic, inhibitor, or small interfering RNA against RUNX1 were used to examine the effects of miR‐101 and RUNX1 on transforming growth factor β signaling pathway, cardiac function, infarct size, myocardial fibrosis, and cardiomyocyte apoptosis. RUNX1 was highly expressed, while miR‐101 was poorly expressed in MI. miR‐101 was identified to target RUNX1. Following that, it was found that overexpression of miR‐101 or silencing of RUNX1 improved the cardiac function and elevated left ventricular end‐diastolic and end‐systolic diameters. Also, miR‐101 elevation or RUNX1 depletion decreased infarct size, myocardial fibrosis, and cardiomyocyte apoptosis. Moreover, miR‐101 could negatively regulate RUNX1 to inactivate the transforming growth factor β1/Smad family member 2 signaling pathway.

Conclusions

Taken together, miR‐101 plays a protective role against cardiac remodeling following MI via inactivation of the RUNX1‐dependent transforming growth factor β1/Smad family member 2 signaling pathway, proposing miR‐101 and RUNX1 as potential therapeutic targets for MI.

microRNA-329 reduces bone cancer pain through the LPAR1-dependent LPAR1/ERK signal transduction pathway in mice

Background:

Bone cancer pain (BCP) is a common symptom occurring among patients with cancer and has a detrimental effect on their quality of life. Growing evidence has implicated microRNA-329 (miR-329) in the progression of bone diseases. In the present study, we aimed to elucidate the potential effects of miR-329 on BCP in a BCP mouse model via binding to lysophosphatidic acid receptor 1 (LPAR1) through the LPAR1/extracellular signal-regulated kinase (ERK) signaling pathway.

Methods:

Initially, a BCP mouse model was established via injection of 4 × 10⁴ murine breast tumor (4T1 cell) cells (4 μl). The interaction between miR-329 and LPAR1 was identified using a bioinformatics website and dual luciferase reporter gene assay. The modeled mice were subsequently treated with miR-329 mimic, LPAR1 shRNA, or both, in order to examine the effect of miR-329 on the paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) of mice, the expression of LPAR1/ERK signaling pathway-related genes.

Results:

The positive expression rate of LPAR1 protein and extent of ERK1/2 phosphorylation were increased in BCP mouse models. LPAR1 is a target gene of miR-329, which can inhibit the expression of LPAR1. In response to miR-329 overexpression and LPAR1 silencing, BCP mice showed increased PWT and PWL, along with decreased LPAR1 expression and ratio of p-ERK/ERK.

Conclusions:

Altogether, the results obtained indicated that miR-329 can potentially alleviate BCP in mice via the inhibition of LPAR1 and blockade of the LPAR1/ERK signaling pathway, highlighting that upregulation of miR-329 could serve as a therapeutic target for BCP treatment.

BMP2-mediated PTEN enhancement promotes differentiation of hair follicle stem cells by inducing autophagy

The proliferation and differentiation of hair follicle stem cells (HFSCs) is regulated by several signaling pathways, including BMP and PTEN. Therefore, this study intended to clarify the potential effects of two such regulators, BMP2 and PTEN, on HFSC differentiation. HFSCs were subjected to BMP2, noggin (BMP2 ligand inhibitor), rapamycin (Rapa, autophagy inducer), 3-methyladenine (3-MA, autophagy inhibitor), or shRNA against PTEN. The differentiation of HFSCs was evaluated using oil red O staining and autophagy was assessed using the transmission electron microscope. Then expression of epidermal differentiation marker (K10 and involucrin), adipogenic markers (PPAR-γ2, aP2, perilipin2, and Adipoq), keratinocyte-specific marker (K15), proliferation-related markers (PCNA and Ki67) and autophagy-related factors (Atg5, Atg7, Atg12, Beclin-1 and LC3-II/LC3-I) was examined by RT-qPCR and Western blot analysis. Next, HFSCs were treated with 3-MA, or shRNA against Atg5 or Atg7 to verify the effect of autophagy on differentiation of BMP2-treated HFSCs. Finally, the effect of BMP2 on HFSC differentiation was verified by a mouse wound model. HFSCs overexpressing BMP2 exhibited elevated expression of epidermal differentiation marker, adipogenic markers and autophagy-related factors but inhibited expression of keratinocyte-specific marker and proliferation-related markers. Furthermore, we found that PTEN promoted the differentiation of BMP2-treated HFSCs by inducing autophagy. In vivo experiments further confirmed the roles of BMP2/PTEN on differentiation of HFSCs. Taken together, BMP2 up-regulated PTEN and consequently induced autophagy to facilitate HFSC differentiation.

Moxibustion alleviates intervertebral disc degeneration via activation of the HIF-1α/VEGF pathway in a rat model

Intervertebral disc degeneration (IDD) induces serious back, neck and radicular pain. Recently, moxibustion has been suggested as an effective treatment for IDD. Thus, our study aims to investigate the molecular mechanism of moxibustion in IDD. A rat model of IDD was established by moxibustion treatment. Nucleus pulposus (NP) cells isolated from IDD rats or IDD rats treated with moxibustion were transfected with plasmids harboring overexpressed hypoxia-inducible factor-1 alpha (HIF-1α) to understand the role of treatment on cell autophagy and apoptosis. To investigate the mechanism of moxibustion in IDD, aggrecan, cyclo-oxygenase 2 (COX-2), HIF-1α and vascular endothelial growth factor (VEGF) expression in NP cells was measured. The expression of aggrecan and COX-2 was elevated by moxibustion treatment. Moxibustion induced autophagy and suppressed apoptosis of NP cells from IDD rats. Compared with IDD rats, the expression of light chain 3 (LC3) II/I, Beclin-1, B-cell lymphoma-2 (Bcl-2) and HIF-1α was regulated significantly after moxibustion treatment, while the expression of cleaved-caspase-3, Bcl-2 associated protein X and VEGF was downregulated. In general, moxibustion may be beneficial to IDD by enhancing autophagy and reducing apoptosis of NP cells via the HIF-1α/VEGF pathway.

Role of hepatocyte nuclear factor 4-alpha in gastrointestinal and liver diseases

Hepatocyte nuclear factor 4-alpha (HNF4α) is a highly conserved member of nuclear receptor superfamily of ligand-dependent transcription factors that is expressed in liver and gastrointestinal organs (pancreas, stomach, and intestine). In liver, HNF4α is best known for its role as a master regulator of liver-specific gene expression and essential for adult and fetal liver function. Dysregulation of HNF4α expression has been associated with many human diseases such as ulcerative colitis, colon cancer, maturity-onset diabetes of the young, liver cirrhosis, and hepatocellular carcinoma. However, the precise role of HNF4α in the etiology of these human pathogenesis is not well understood. Limited information is known about the role of HNF4α isoforms in liver and gastrointestinal disease progression. There is, therefore, a critical need to know how disruption of the expression of these isoforms may impact on disease progression and phenotypes. In this review, we will update our current understanding on the role of HNF4α in human liver and gastrointestinal diseases. We further provide additional information on possible use of HNF4α as a target for potential therapeutic approaches.