A Novel Sox9/lncRNA H19 Axis Contributes to Hepatocyte Death and Liver Fibrosis

Influence of Sex in the Development of Liver Diseases

The liver is a sexually dimorphic organ. Sex differences in prevalence, progression, prognosis, and treatment prevail in most liver diseases, and the mechanism of how liver diseases act differently among male versus female patients has not been fully elucidated. Biological sex differences in normal physiology and disease arise principally from sex hormones and/or sex chromosomes. Sex hormones contribute to the development and progression of most liver diseases, with estrogen- and androgen-mediated signaling pathways mechanistically involved. In addition, genetic factors in sex chromosomes have recently been found to contribute to the sex disparity of many liver diseases, which might explain, to some extent, the difference in gene expression pattern, immune response, and xenobiotic metabolism between men and women. Although increasing evidence suggests that sex is one of the most important modulators of disease prevalence and outcomes, at present, basic and clinical studies have long been sex unbalanced, with female subjects underestimated. As such, this review focuses on sex disparities of liver diseases and summarizes the current understanding of sex-specific mechanisms, including sex hormones, sex chromosomes, etc. We anticipate that understanding sex-specific pathogenesis will aid in promoting personalized therapies for liver disease among male versus female patients.

Identification of SOX9-related prognostic DEGs and a prediction model for hepatitis C-induced early-stage fibrosis

BACKGROUND

Hepatitis C virus (HCV) infection induces liver inflammation, activating hepatic stellate cells (HSC) and advancing fibrosis. Studies have indicated that SOX9 overexpression is closely linked to HSC activation. The study aims to identify genes associated with SOX9 and search for potential targets for detecting and treating liver fibrosis.

METHOD

The dataset GSE15654, containing 216 biopsy samples from HCV-induced early-stage cirrhosis patients, was obtained from the GEO database. Prognostic genes were identified through differential gene analysis, LASSO, and Cox regression analyses. CIBERSORT analysis quantified infiltration levels across 22 immune cell types. Constructing a prognostic prediction model using screened genes and conducting preliminary validation using qRT PCR and RNA sequencing techniques.

RESULTS

Elevated SOX9 expression correlates with unfavorable outcomes in patients with early-stage liver fibrosis induced by HCV. We identified nine SOX9-related prognostic DEGs in our study. ADAMTS2, ARHGEF5, CCT8, ERG, LBH, FRMD6, INMT, and RASGRF2 were considered risk factors in the disease progression, while DHRS4 was considered a protective factor. SOX9 expression showed a positive correlation with mast cell infiltration, whereas ARHGEF5 and FRMD6 expressions were positively associated with M0 macrophage infiltration. Our combined model surpasses the commonly used APRI and FIB4 indicators in predicting patient prognosis. The testing of clinical samples also preliminarily validated our research results.

CONCLUSION

The prognostic model based on nine SOX9-related DEGs provides an effective tool for forecasting the progression and outcomes of liver fibrosis. This study introduces a new strategy for advancing liver fibrosis prediction and treatment.

SOX9: a key transcriptional regulator in organ fibrosis

The SOX9 gene locus is not only extensive but also intricate, and it could promote fibrosis in different organs or tissues, including cardiac fibrosis, liver fibrosis, kidney fibrosis, pulmonary fibrosis, as well as other organ fibrosis. Many disorders are associated with the process of fibrosis; moreover, fibrosis is a common symptom of chronic inflammatory diseases, characterized by the accumulation of excessive components in the extracellular matrix through different signaling pathways. The advanced stage of the fibrotic process leads to organ dysfunction and, ultimately, death. In this review, we first give an overview of the original structure and functions of SOX9. Second, we will discuss the role of SOX9 in fibrosis in various organs or tissues. Third, we describe and reveal the possibility of SOX9 as an antifibrotic treatment target. Finally, we will focus on the application of novel technologies for SOX9 and the subsequent investigation of fibrosis.

Noninvasive identification of SOX9 status using radiomics signatures may help construct personalized treatment strategy in hepatocellular carcinoma

OBJECTIVES

To develop and validate a radiomics-based model for predicting SOX9-positive hepatocellular carcinoma (HCC) using preoperative contrast-enhanced computed tomography (CT) images.

METHODS

From January 2013 to April 2017, patients with histologically proven HCC who received systemic sorafenib treatment after curative resection were retrospectively enrolled. Radiomic features were extracted from portal venous phase CT images and selected to build a radiomics score using logistic regression analysis. The factors associated with SOX9 expression were selected and combined by univariate and multivariate analyses to establish clinico-liver imaging (CL) model and clinico-liver imaging-radiomics (CLR) model. Diagnostic performance was measured by area under curve (AUC). Overall survival (OS) and recurrence-free survival (RFS) rates were compared using Kaplan-Meier method.

RESULTS

A total of 108 patients (training cohort: n = 80; validation cohort: n = 28) were enrolled. Multivariate analyses revealed that the albumin-bilirubin grade and tumor size were significant independent factors for predicting SOX9-positive HCCs and were included in the CL model. The CLR model integrating the radiomics score with albumin-bilirubin grade and tumor size showed better discriminative performance than the CL model with AUCs of 0.912 and 0.790 in the training and validation cohorts. Survival curves for RFS and OS showed that SOX9 expression was closely related to the prognosis of HCC patients. RFS and OS rates were significantly lower in patients with SOX9-positive than SOX9-negative (51.02% vs. 75.00% at 1-year RFS rates; 76.92% vs. 94.94% at 2-year OS rates).

CONCLUSION

Radiomics signatures may serve as noninvasive predictors for SOX9 status evaluation in patients with HCC and may aid in constructing individualized treatment strategies.

Diverse functions of SOX9 in liver development and homeostasis and hepatobiliary diseases

The liver is the central organ for digestion and detoxification and has unique metabolic and regenerative capacities. The hepatobiliary system originates from the foregut endoderm, in which cells undergo multiple events of cell proliferation, migration, and differentiation to form the liver parenchyma and ductal system under the hierarchical regulation of transcription factors. Studies on liver development and diseases have revealed that SRY-related high-mobility group box 9 (SOX9) plays an important role in liver embryogenesis and the progression of hepatobiliary diseases. SOX9 is not only a master regulator of cell fate determination and tissue morphogenesis, but also regulates various biological features of cancer, including cancer stemness, invasion, and drug resistance, making SOX9 a potential biomarker for tumor prognosis and progression. This review systematically summarizes the latest findings of SOX9 in hepatobiliary development, homeostasis, and disease. We also highlight the value of SOX9 as a novel biomarker and potential target for the clinical treatment of major liver diseases.

The Role of SOX9 in IGF-II-Mediated Pulmonary Fibrosis

Pulmonary fibrosis (PF) associated with systemic sclerosis (SSc) results in significant morbidity and mortality. We previously reported that insulin-like growth factor-II (IGF-II) is overexpressed in lung tissues and fibroblasts from SSc patients, and IGF-II fosters fibrosis by upregulating collagen type I, fibronectin, and TGFβ. We now show that IGF-II augments mRNA levels of profibrotic signaling molecules TGFβ2 (p ≤ 0.01) and TGFβ3 (p ≤ 0.05), collagen type III (p ≤ 0.01), and the collagen posttranslational modification enzymes P4HA2 (p ≤ 0.05), P3H2 (p ≤ 0.05), LOX (p = 0.065), LOXL2 (p ≤ 0.05), LOXL4 (p ≤ 0.05) in primary human lung fibroblasts. IGF-II increases protein levels of TGFβ2 (p ≤ 0.01), as well as COL3A1, P4HA2, P4Hβ, and LOXL4 (p ≤ 0.05). In contrast, IGF-II decreases mRNA levels of the collagen degradation enzymes cathepsin (CTS) K, CTSB, and CTSL and protein levels of CTSK (p ≤ 0.05). The SRY-box transcription factor 9 (SOX9) is overexpressed in SSc lung tissues at the mRNA (p ≤ 0.05) and protein (p ≤ 0.01) levels compared to healthy controls. IGF-II induces SOX9 in lung fibroblasts (p ≤ 0.05) via the IGF1R/IR hybrid receptor, and SOX9 regulates TGFβ2 (p ≤ 0.05), TGFβ3 (p ≤ 0.05), COL3A1 (p ≤ 0.01), and P4HA2 (p ≤ 0.001) downstream of IGF-II. Our results identify a novel IGF-II signaling axis and downstream targets that are regulated in a SOX9-dependent and -independent manner. Our findings provide novel insights on the role of IGF-II in promoting pulmonary fibrosis.

lncRNAs in fertility: redefining the gene expression paradigm?

Comparative transcriptome approaches assume that highly or dynamically expressed genes are important. This has led to the identification of many genes critical for cellular activity and organism development. However, while testes express the highest levels of long noncoding RNAs (lncRNAs), there is scarcely any evidence for lncRNAs with significant roles in fertility. This was explained by changes in chromatin structure during spermatogenesis that lead to 'promiscuous transcription' with no functional roles for the transcripts. Recent discoveries offer novel and surprising alternatives. Here, I review the current knowledge regarding the involvement of lncRNAs in fertility, why I find gametogenesis different from other developmental processes, offer models to explain why the experimental evidence did not meet theoretical predictions, and suggest possible approaches to test the models.

Serum non-coding RNAs for diagnosis and stage of liver fibrosis

Background

All chronic liver diseases could lead to liver fibrosis. Accurate diagnosis and stage of fibrosis were important for the medical determination, management, and therapy. Liver biopsy was considered to be the gold criteria of fibrosis diagnosis. However, liver biopsy was an invasive method with some drawbacks. Non‐invasive tests for liver fibrosis included radiologic method and serum‐based test. Radiologic examination was influenced by obesity, cost, and availability. Serum‐based test was widely used in the screening and diagnostic of liver fibrosis. However, the accuracy was still needed to be improved.

Methods

Recent studies showed serum non‐coding RNAs: microRNA, long non‐coding RNA(lncRNA), and circular RNA(circRNA), which have the potentiality to be non‐invasive markers for liver fibrosis. The recent progress was summarized in this review.

Results

These studies showed serum non‐coding RNAs exerted a good diagnostic performance for liver fibrosis. A panel that included several non‐coding RNAs could increase the accuracy of single marker.

Conclusions

Serum microRNAs, lncRNAs, and circRNAs could be potential non‐invasive markers for diagnosis and stage of liver fibrosis. More high‐quality clinical study is needed for further research.

Potential biomarkers in the fibrosis progression of nonalcoholic steatohepatitis (NASH)

PURPOSE

Fibrosis is the only histological feature reflecting the severity and prognosis of nonalcoholic steatohepatitis (NASH). We aim to explore novel genes associated with fibrosis progression in NASH.

METHODS

Two human RNA-seq datasets were downloaded from the public database. Weighted gene co-expression network analysis (WGCNA) was used to identify their co-expressed modules and further bioinformatics analysis was performed to identify hub genes within the modules. Finally, based on two single-cell RNA-seq datasets from mice and one microarray dataset from human, we further observed the expression of hub genes in different cell clusters and liver tissues.

RESULTS

7 hub genes (SPP1, PROM1, SOX9, EPCAM, THY1, CD34 and MCAM) associated with fibrosis progression were identified. Single-cell RNA-seq analysis revealed that those hub genes were expressed by different cell clusters such as cholangiocytes, natural killer (NK) cells, and hepatic stellate cells (HSCs). We also found that SPP1 and CD34 serve as markers of different HSCs clusters, which are associated with inflammatory response and fibrogenesis, respectively. Further study suggested that SPP1, SOX9, MCAM and THY1 might be related to NASH-associated hepatocellular carcinoma (HCC). Receiver operating characteristic (ROC) analysis showed that the high expression of these genes could well predict the occurrence of HCC. At the same time, there were significant differences in metabolism-related pathway changes between different HCC subtypes, and SOX9 may be involved in these changes.

CONCLUSIONS

The present study identified novel genes associated with NASH fibrosis and explored their effects on fibrosis from a single-cell perspective that might provide new ideas for the early diagnosis, monitoring, evaluation, and prediction of fibrosis progression in NASH.

Bellidifolin Inhibits SRY-Related High Mobility Group-Box Gene 9 to Block TGF-β Signalling Activation to Ameliorate Myocardial Fibrosis

Myocardial fibrosis is the main morphological change of ventricular remodelling caused by cardiovascular diseases, mainly manifested due to the excessive production of collagen proteins. SRY-related high mobility group-box gene 9 (SOX9) is a new target regulating myocardial fibrosis. Bellidifolin (BEL), the active component of G. acuta, can prevent heart damage. However, it is unclear whether BEL can regulate SOX9 to alleviate myocardial fibrosis. The mice were subjected to isoproterenol (ISO) to establish myocardial fibrosis, and human myocardial fibroblasts (HCFs) were activated by TGF-β1 in the present study. The pathological changes of cardiac tissue were observed by HE staining. Masson staining was applied to reveal the collagen deposition in the heart. The measurement for expression of fibrosis-related proteins, SOX9, and TGF-β1 signalling molecules adopted Western blot and immunohistochemistry. The effects of BEL on HCFs, activity were detected by CCK-8. The result showed that BEL did not affect cell viability. And, the data indicated that BEL inhibited the elevations in α-SMA, Collagen I, and Collagen III by decreasing SOX9 expression. Additionally, SOX9 suppression by siRNA downregulated the TGF-β1 expression and prevented Smad3 phosphorylation, as supported by reducing the expression of α-SMA, Collagen I, and Collagen III. In vivo study verified that BEL ameliorated myocardial fibrosis by inhibiting SOX9. Therefore, BEL inhibited SOX9 to block TGF-β1 signalling activation to ameliorate myocardial fibrosis.

Tubule-derived INHBB promotes interstitial fibroblast activation and renal fibrosis

Upstream stimuli for myofibroblast activation are of considerable interest for understanding the mechanisms underlying renal fibrosis. Activin B, a member of the TGF-β family, exists as a homodimer of inhibin subunit beta B (INHBB), but its role in renal fibrosis remains unknown. We found that INHBB expression was significantly increased in various renal fibrosis models and human chronic kidney disease specimens with renal fibrosis. Notably, the increase of INHBB occurred mainly in the tubular epithelial cells (TECs). In vivo, inhibiting INHBB blocked the activation of interstitial fibroblasts and ameliorated the renal fibrosis induced by unilateral ureteral obstruction or ischemia-reperfusion injury, while ectopic expression of INHBB in the TECs was able to activate interstitial fibroblasts and initiate interstitial fibrosis. In vitro, overexpression of INHBB in TECs led to the secretion of activin B, thereby promoting the proliferation and activation of interstitial fibroblasts through activin B/Smad signaling. Furthermore, inhibition of activin B/Smad signaling attenuated the fibrotic response caused by tubular INHBB. Mechanistically, the upregulation of INHBB depended on the transcription factor Sox9 in the injured TECs. Clinical analyses also identified a positive correlation between Sox9 and INHBB expression in human specimens, suggesting the Sox9/INHBB axis as a positive regulator of renal fibrosis. In conclusion, tubule-derived INHBB is implicated in the pathogenesis of renal fibrosis by activating the surrounding fibroblasts in a paracrine manner, thereby exhibiting as a potential therapeutic target. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Activin B, a new player in kidney fibrosis?†

Interest has been growing in the role of activin A in both acute and chronic kidney disease. The role of other activins, however, remains relatively unexplored. In a recent issue of the Journal of Pathology, an elegant study by Sun et al. identified upregulation of INHBB, the subunit of activin B, in three different models of kidney fibrosis, as well as in human kidneys with fibrosis. This increase was shown to be mediated by upregulation of the transcription factor Sox9. Using overexpression and inhibition strategies, the importance of INHBB to kidney interstitial fibroblast activation and kidney fibrosis was clearly shown. Importantly, INHBB and Sox9 are not appreciably expressed in normal tissue. These studies lay important groundwork for the further investigation of activin B targeting as a potential therapeutic approach to attenuate kidney fibrosis. This article is protected by copyright. All rights reserved.

Identification of differentially expressed long noncoding RNAs and pathways in liver tissues from rats with hepatic fibrosis

To identify long non-coding RNAs (lncRNAs) and their potential roles in hepatic fibrosis in rat liver issues induced by CCl4, lncRNAs and genes were analyzed in fibrotic rat liver tissues by RNA sequencing and verified by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Differentially expressed (DE) lncRNAs (DE-lncRNAs) and genes were subjected to bioinformatics analysis and used to construct a co-expression network. We identified 10 novel DE-lncRNAs that were downregulated during the hepatic fibrosis process. The cis target gene of DE-lncRNA, XLOC118358, was Met, and the cis target gene of the other nine DE-lncRNAs, XLOC004600, XLOC004605, XLOC004610, XLOC004611, XLOC004568, XLOC004580 XLOC004598, XLOC004601, and XLOC004602 was Nox4. The results of construction of a pathway-DEG co-expression network show that lncRNA-Met and lncRNAs-Nox4 were involved in oxidation-reduction processes and PI3K/Akt signaling pathway. Our results identified 10 DE-lncRNAs related to hepatic fibrosis, and the potential roles of DE-lncRNAs and target genes in hepatic fibrosis might provide new therapeutic strategies for hepatic fibrosis.

Role of miRNA and lncRNAs in organ fibrosis and aging

Fibrosis is the endpoint of pathological remodeling. This process contributes to the pathogenesis of several chronic disorders and aging-associated organ damage. Different molecular cascades contribute to this process. TGF-β, WNT, and YAP/TAZ signaling pathways have prominent roles in this process. A number of long non-coding RNAs and microRNAs have been found to regulate organ fibrosis through modulation of the activity of related signaling pathways. miR-144-3p, miR-451, miR-200b, and miR-328 are among microRNAs that participate in the pathology of cardiac fibrosis. Meanwhile, miR-34a, miR-17-5p, miR-122, miR-146a, and miR-350 contribute to liver fibrosis in different situations. PVT1, MALAT1, GAS5, NRON, PFL, MIAT, HULC, ANRIL, and H19 are among long non-coding RNAs that participate in organ fibrosis. We review the impact of long non-coding RNAs and microRNAs in organ fibrosis and aging-related pathologies.