Quantitative Proteomic analysis on Activated Hepatic Stellate Cells reversion Reveal STAT1 as a key regulator between Liver Fibrosis and recovery

The Role of miRNA in Renal Fibrosis Leading to Chronic Kidney Disease

Chronic kidney disease (CKD) is an important health concern that is expected to be the fifth most widespread cause of death worldwide by 2040. The presence of chronic inflammation, oxidative stress, ischemia, etc., stimulates the development and progression of CKD. Tubulointerstitial fibrosis is a common pathomechanism of renal dysfunction, irrespective of the primary origin of renal injury. With time, fibrosis leads to end-stage renal disease (ESRD). Many studies have demonstrated that microRNAs (miRNAs, miRs) are involved in the onset and development of fibrosis and CKD. miRNAs are vital regulators of some pathophysiological processes; therefore, their utility as therapeutic agents in various diseases has been suggested. Several miRNAs were demonstrated to participate in the development and progression of kidney disease. Since renal fibrosis is an important problem in chronic kidney disease, many scientists have focused on the determination of miRNAs associated with kidney fibrosis. In this review, we present the role of several miRNAs in renal fibrosis and the potential pathways involved. However, as well as those mentioned above, other miRs have also been suggested to play a role in this process in CKD. The reports concerning the impact of some miRNAs on fibrosis are conflicting, probably because the expression and regulation of miRNAs occur in a tissue- and even cell-dependent manner. Moreover, different assessment modes and populations have been used. There is a need for large studies and clinical trials to confirm the role of miRs in a clinical setting. miRNAs have great potential; thus, their analysis may improve diagnostic and therapeutic strategies.

Glycyrrhizic acid alleviates liver fibrosis in vitro and in vivo via activating CUGBP1-mediated IFN-γ/STAT1/Smad7 pathway

BACKGROUND

Hepatic fibrosis, a common pathological feature of chronic liver injuries, is a serious public health problem and lacks effective therapy. Glycyrrhizic acid (GA) is a bioactive ingredient in the root of traditional Chinese medicine licorice, and exhibits remarkable anti-viral, anti-inflammatory and hepatoprotective actions.

PURPOSE

Here we aimed to investigated whether GA provided a therapeutic efficacy in hepatic fibrosis and uncover its molecular mechanisms.

STUDY DESIGN AND METHODS

We investigated the anti-fibrosis effects of GA using CCl₄-induced mouse mode of liver fibrosis as well as TGF-β1-activated human LX-2 cells and primary hepatic stellate cells (HSCs). CUGBP1-mediated IFN-γ/STAT1/Smad7 signaling was examined with immunofluorescence staining and western blot analysis. We designed and studied the binding of GA to CUGBP1 using in silico docking, and validated by microscale thermophoresis (MST) assay.

RESULTS

GA obviously attenuated CCl₄-induced liver histological damage, and reduced serum ALT and AST levels. Meanwhile, GA decreased liver fibrogenesis markers such as α-SMA, collagen α1, HA, COL-III, and LN in the hepatic tissues. Mechanistically, GA remarkably elevated the levels of IFN-γ, p-STAT1, Smad7, and decreased CUGBP1 in vivo and in vitro. Over-expression of CUGBP1 completely abolished the anti-fibrotic effect of GA and regulation on IFN-γ/STAT1/Smad7 pathway in LX-2 cells and primary HSCs, confirming CUGBP1 played a pivotal role in the protection by GA from liver fibrosis. Further molecular docking and MST assay indicated that GA had a good binding affinity with the CUGBP1 protein. The dissociation constant (Kd) of GA and CUGBP1 was 0.293 μM.

CONCLUSION

Our study demonstrated for the first time that GA attenuated liver fibrosis and hepatic stellate cell activation by promoting CUGBP1-mediated IFN-γ/STAT1/Smad7 signalling pathways. GA may be a potential candidate compound for preventing or reliving liver fibrosis.

The Role of JAK/STAT Pathway in Fibrotic Diseases: Molecular and Cellular Mechanisms

There are four members of the JAK family and seven of the STAT family in mammals. The JAK/STAT molecular pathway could be activated by broad hormones, cytokines, growth factors, and more. The JAK/STAT signaling pathway extensively mediates various biological processes such as cell proliferation, differentiation, migration, apoptosis, and immune regulation. JAK/STAT activation is closely related to growth and development, homeostasis, various solid tumors, inflammatory illness, and autoimmune diseases. Recently, with the deepening understanding of the JAK/STAT pathway, the relationship between JAK/STAT and the pathophysiology of fibrotic diseases was noticed, including the liver, renal, heart, bone marrow, and lung. JAK inhibitor has been approved for myelofibrosis, and subsequently, JAK/STAT may serve as a promising target for fibrosis in other organs. Therefore, this article reviews the roles and mechanisms of the JAK/STAT signaling pathway in fibrotic diseases.

Effects of Exosomes Derived From Helicobacter pylori Outer Membrane Vesicle-Infected Hepatocytes on Hepatic Stellate Cell Activation and Liver Fibrosis Induction

Liver fibrosis is a multifactorial disease with microbial and non-microbial causes. In recent years, Helicobacter pylori infection has been thought to play a critical role in some extra-gastrointestinal manifestations especially liver disorders. Outer membrane vesicles (OMVs) are one of the most important discussed H. pylori virulence factors. In the current study, four different clinical strains of H. pylori were collected and their OMVs were purified using ultra-centrifugation. To investigate their effects on liver cell exosomes, co-incubation with hepatocytes was applied. After a while, hepatocyte-derived exosomes were extracted and incubated with hepatic stellate cells (HSCs) to investigate the HSC activation and fibrosis marker induction. The expression of α-SMA, TIMP-1, β-catenin, vimentin, and e-cadherin messenger RNAs (mRNA) was assessed using real-time RT-PCR, and the protein expression of α-SMA, TIMP-1, β-catenin, vimentin, and e-cadherin was evaluated by Western blotting. Our results showed that infected hepatocyte-derived exosomes induced the expression of α-SMA, TIMP-1, β-catenin, and vimentin in HSCs and e-cadherin gene and protein expression was downregulated. In the current study, we found that H. pylori-derived OMVs may aid the exosome alternation and modified exosomes may have a possible role in HSC activation and liver fibrosis progression.

Dynamic human liver proteome atlas reveals functional insights into disease pathways

Deeper understanding of liver pathophysiology would benefit from a comprehensive quantitative proteome resource at cell type resolution to predict outcome and design therapy. Here, we quantify more than 150,000 sequence‐unique peptides aggregated into 10,000 proteins across total liver, the major liver cell types, time course of primary cell cultures, and liver disease states. Bioinformatic analysis reveals that half of hepatocyte protein mass is comprised of enzymes and 23% of mitochondrial proteins, twice the proportion of other liver cell types. Using primary cell cultures, we capture dynamic proteome remodeling from tissue states to cell line states, providing useful information for biological or pharmaceutical research. Our extensive data serve as spectral library to characterize a human cohort of non‐alcoholic steatohepatitis and cirrhosis. Dramatic proteome changes in liver tissue include signatures of hepatic stellate cell activation resembling liver cirrhosis and providing functional insights. We built a web‐based dashboard application for the interactive exploration of our resource (www.liverproteome.org).

Proteomic Changes of Activated Hepatic Stellate Cells

Hepatic stellate cells (HSC) are the major cellular drivers of liver fibrosis. Upon liver inflammation caused by a broad range of insults including non-alcoholic fatty liver, HSC transform from a quiescent into a proliferating, fibrotic phenotype. Although much is known about the pathophysiology of this process, exact cellular processes which occur in HSC and enable this transformation remain yet to be elucidated. In order to investigate this HSC transformation, we employed a simple, yet reliable model of HSC activation via an increase in growth medium serum concentration (serum activation). For that purpose, immortalized human LX-2 HSC were exposed to either 1% or 10% fetal bovine serum (FBS). Resulting quiescent (1% FBS) and activated (10% FBS) LX-2 cells were then subjected to in-depth mass spectrometry-based proteomics analysis as well as comprehensive phenotyping. Protein network analysis of activated LX-2 cells revealed an increase in the production of ribosomal proteins and proteins related to cell cycle control and migration, resulting in higher proliferation and faster migration phenotypes. Interestingly, we also observed a decrease in the expression of cholesterol and fatty acid biosynthesis proteins in accordance with a concomitant loss of cytosolic lipid droplets during activation. Overall, this work provides an update on HSC activation characteristics using contemporary proteomic and bioinformatic analyses and presents an accessible model for HSC activation. Data are available via ProteomeXchange with identifier PXD029121.

NAMPT-mediated NAD+ biosynthesis suppresses activation of hepatic stellate cells and protects against CCl4-induced liver fibrosis in mice

Background: Nicotinamide phosphoribosyltransferase (NAMPT) catalyzes the rate-limiting step in the salvage pathway of mammalian nicotinamide adenine dinucleotide (NAD⁺) biosynthesis. Through its NAD⁺-biosynthetic activity, NAMPT is able to regulate the development of hepatic steatosis and inflammation induced by diet or alcohol. However, the roles NAMPT plays in the development of liver fibrosis remain obscure. Purpose: To investigate the roles of NAMPT-mediated NAD⁺ biosynthesis in hepatic stellate cell (HSC) activation and liver fibrosis. Research Design: Realtime RT-PCR and western blot analyses were performed to analyze the expression of profibrogenic genes. Sirius red staining was conducted to examine the fibrosis in liver. Mouse liver fibrosis was induced by intraperitoneal injection of carbon tetrachloride (CCl₄) 2 times a week for 6 weeks. Adenovirus-mediated NAMPT overexpression or nicotinamide mononucleotide (NMN) administration was carried out to study the effects of elevation of NAD⁺ levels on protecting CCl₄-induced liver fibrosis in mice. LX2 cells or primary HSCs were used to study the role of NAMPT overexpression or NMN treatment in reducing profibrogenic gene expression in vitro. ResultsCCl₄ administration suppresses NAMPT expression in liver and reduces hepatic NAD⁺ content. Tgfβ1 treatment decreases intracellular NAD⁺ levels and NAMPT expression in LX2 cells. Adenovirus-mediated NAMPT overexpression augments liver NAD⁺ levels, inhibits HSC activation and alleviates CCl₄-induced liver fibrosis in mice. Administration of NMN also suppresses HSC activation and protects against CCl₄-induced liver fibrosis in mice. Conclusions: NAMPT-mediated NAD⁺ biosynthesis inhibits HSC activation and protects against CCl₄-induced liver fibrosis.

Discovery and validation of novel protein markers in mucosa of portal hypertensive gastropathy

Background

Portal hypertension induced esophageal and gastric variceal bleeding is the main cause of death among patients of decompensated liver cirrhosis. Therefore, a standardized, biomarker-based test, to make an early-stage non-invasive risk assessment of portal hypertension, is highly desirable. However, no fit-for-purpose biomarkers have yet been identified.

Methods

We conducted a pilot study consisting of 5 portal hypertensive gastropathy (PHG) patients and 5 normal controls, sampling the gastric mucosa of normal controls and PHG patients before and after endoscopic cyanoacrylate injection, using label-free quantitative (LFQ) mass spectrometry, to identify potential biomarker candidates in gastric mucosa from PHG patients and normal controls. Then we further used parallel reaction monitoring (PRM) to verify the abundance of the targeted protein.

Results

LFQ analyses identified 423 significantly differentially expressed proteins. 17 proteins that significantly elevated in the gastric mucosa of PHG patients were further validated using PRM.

Conclusions

This is the first application of an LFQ-PRM workflow to identify and validate PHG–specific biomarkers in patient gastric mucosa samples. Our findings lay the foundation for comprehending the molecular mechanisms of PHG pathogenesis, and provide potential applications for useful biomarkers in early diagnosis and treatment.

Trial registration and ethics approval: Trial registration was completed (ChiCTR2000029840) on February 25, 2020. Ethics Approvals were completed on July 17, 2017 (NYSZYYEC20180003) and February 15, 2020 (NYSZYYEC20200005).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01787-5.

MiR-27b-3p inhibits the progression of renal fibrosis via suppressing STAT1

Renal fibrosis is a pathologic change in chronic kidney disease (CKD). MicroRNAs (miRNAs) have been shown to play an important role in the development of renal fibrosis. However, the biological role of miR-27b-3p in renal fibrosis remains unclear. Thus, this study aimed to investigate the role of miR-27b-3p in the progression of renal fibrosis. In this study, HK-2 cells were stimulated with transforming growth factor (TGF)-β1 for mimicking fibrosis progression in vitro. The unilateral ureteric obstruction (UUO)-induced mice renal fibrosis in vivo was established as well. The results indicated that the overexpression of miR-27b-3p significantly inhibited epithelial-to-mesenchymal transition (EMT) in TGF-β1-stimulated HK-2 cells, as shown by the decreased expressions of α-SMA, collagen III, Fibronectin and Vimentin. In addition, overexpression of miR-27b-3p markedly decreased TGF-β1-induced apoptosis in HK-2 cells, as evidenced by the decreased levels of Fas, active caspase 8 and active caspase 3. Meanwhile, dual-luciferase assay showed that miR-27b-3p downregulated signal transducers and activators of transcription 1 (STAT1) expression through direct binding with the 3′-UTR of STAT1. Furthermore, overexpression of miR-27b-3p attenuated UUO-induced renal fibrosis via downregulation of STAT1, α-SMA and collagen III. In conclusion, miR-27b-3p overexpression could alleviate renal fibrosis via suppressing STAT1 in vivo and in vitro. Therefore, miR-27b-3p might be a promising therapeutic target for the treatment of renal fibrosis.

Impact of STAT1 polymorphisms on crizotinib-induced hepatotoxicity in ALK-positive non-small cell lung cancer patients

PURPOSE

Crizotinib is the first-line small molecule tyrosine kinase inhibitor for ALK-positive non-small cell lung cancer. In this study, a retrospective pharmacogenomics investigation was conducted to explore the relationship between genes related to RTK downstream signaling pathways and crizotinib-induced hepatic toxicity in ALK-positive NSCLC patients.

METHODS

The variable importance analysis of random forest algorithm was applied to identify the significant features which contribute to the crizotinib sensitivity in Cancer Cell Line Encyclopedia (CCLE) database. The KEGG and reactome pathway enrichment analysis were conducted with EnrichR. The differential expression genes were identified with R package DESeq2 in CCLE liver derived cell lines between crizotinib sensitive and resistant groups. From 2012 to 2015, 42 NSCLC patients were enrolled in this study. 90 polymorphisms were genotyped using the Sequenom Massarray system. Sequencing of HGFR (c-Met) genes was carried out on the Ion Torrent Proton.

RESULTS

In total, 66.7% NSCLC patients suffered from crizotinib-induced liver toxicity and 11.9% progressed to severe hepatic toxicity. The features with the top importance from classification and regression random forest model were enriched in RTK downstream signaling pathways (JAK/STAT, RAS/RAF/MAPK, PI3K/AKT pathways) and immune system-related pathways. Collagen family genes (COL1A1, COL1A2, COL6A1, COL5A1) and other extracellular matrix protein (TNC, TAGLN, TENM2, EDIL3, VCAN, CNN1, SH3BP4, TAGLN), which were closely related to MAPK-ERK signaling pathways, were significantly enriched in crizotinib resistant cell lines. In multiple logistic regression, STAT1 rs10208033 (T > C) was significantly associated with crizotinib-induced liver toxicity (OR = 6.733, 95% CI 1.406-32.24, P = 0.017). Compared with non-CC, OR is 5.5 (95% CI 1.219-24.81, P = 0.027) for STAT1 rs10208033 CC genotype to develop crizotinib-induced liver toxicity. Further cell viability test in human fetal hepatocyte line, L-02, reveals that the STAT1 inhibitor might protect hepatocyte cells from the toxicity caused by crizotinib.

CONCLUSION

Polymorphism of rs10208033 is a potential biomarker for predicting crizotinib-induced hepatotoxicity. These results suggest that STAT1 plays an important role in crizotinib-induced hepatotoxicity. Further studies are needed to confirm our finding and understand the underlying mechanisms.

Metabolic Signature of Hepatic Fibrosis: From Individual Pathways to Systems Biology

Hepatic fibrosis is a major cause of morbidity and mortality worldwide, as it ultimately leads to cirrhosis, which is estimated to affect up to 2% of the global population. Hepatic fibrosis is confirmed by liver biopsy, and the erroneous nature of this technique necessitates the search for noninvasive alternatives. However, current biomarker algorithms for hepatic fibrosis have many limitations. Given that the liver is the largest organ and a major metabolic hub in the body, probing the metabolic signature of hepatic fibrosis holds promise for the discovery of new markers and therapeutic targets. Regarding individual metabolic pathways, accumulating evidence shows that hepatic fibrosis leads to alterations in carbohydrate metabolism, as aerobic glycolysis is aggravated in activated hepatic stellate cells (HSCs) and the whole fibrotic liver; in amino acid metabolism, as Fischer’s ratio (branched-chain amino acids/aromatic amino acids) decreases in patients with hepatic fibrosis; and in lipid metabolism, as HSCs lose vitamin A-containing lipid droplets during transdifferentiation, and cirrhotic patients have decreased serum lipids. The current review also summarizes recent findings of metabolic alterations relevant to hepatic fibrosis based on systems biology approaches, including transcriptomics, proteomics, and metabolomics in vitro, in animal models and in humans.

FoxO1-mediated inhibition of STAT1 alleviates tubulointerstitial fibrosis and tubule apoptosis in diabetic kidney disease

Background

Tubulointerstitial fibrosis (TIF) plays an important role in the progression of diabetic kidney disease (DKD). Forkhead box O1 (FoxO1) is involved in the regulation of metabolism and cell apoptosis, but its function in renal TIF induced by DKD is less well understood.

Methods

Human kidney biopsies with DKD and normal controls were used to detect apoptosis and TIF induced by diabetes. A mouse model with kidney-specific overexpression of Pax2-3aFoxO1 was established to further investigate the functions of FoxO1 in vivo. The in vitro roles of FoxO1 were analyzed in HK-2 cells with 3aFoxO1-knockin (3aFoxO1-KI) or FoxO1-knockdown (FoxO1-KD) via CRISPR/Cas9. Western blot, immunohistochemistry, and chromatin immunoprecipitation were used to explore the underlying mechanisms.

Findings

In this study, DKD patients had increased renal TIF and apoptosis. In vivo study showed that kidney-specific overexpression of Pax2-3aFoxO1 significantly reduced the expression of p-STAT1 with resultant renal functional impairment, retarding renal TIF and apoptosis in diabetic mice. Meanwhile, We observed that FoxO1-KD in HK-2 cells aggravated the expression of p-STAT1, leading to activation of epithelial-to-mesenchymal transition (EMT) and intrinsic apoptotic pathway. Conversely, EMT and apoptosis were significantly attenuated in HK-2 cells with 3aFoxO1-KI under hyperglycemic conditions.

Interpretation

Taken together, these data suggest that the protection role of FoxO1 against renal TIF and apoptosis in DKD is likely in part to target STAT1 signaling, which may be a promising strategy for long-term treatment of DKD.

Fund

This work was supported by grants from the National Natural Science Foundation of China (grant numbers: 81570746 and 81770812).

Nicotinamide riboside, an NAD+ precursor, attenuates the development of liver fibrosis in a diet-induced mouse model of liver fibrosis

OBJECTIVE

Liver fibrosis is part of the non-alcoholic fatty liver disease (NAFLD) spectrum, which currently has no approved pharmacological treatment. In this study, we investigated whether supplementation of nicotinamide riboside (NR), a nicotinamide adenine dinucleotide (NAD+) precursor, can reduce the development of liver fibrosis in a diet-induced mouse model of liver fibrosis.

METHODS

Male C57BL/6 J mice were fed a low-fat control (LF), a high-fat/high-sucrose/high-cholesterol control (HF) or a HF diet supplemented with NR at 400 mg/kg/day (HF-NR) for 20 weeks. Features of liver fibrosis were assessed by histological and biochemical analyses. Whole-body energy metabolism was also assessed using indirect calorimetry. Primary mouse and human hepatic stellate cells were used to determine the anti-fibrogenic effects of NR in vitro.

RESULTS

NR supplementation significantly reduced body weight of mice only 7 weeks after mice were on the supplementation, but did not attenuate serum alanine aminotransferase levels, liver steatosis, or liver inflammation. However, NR markedly reduced collagen accumulation in the liver. RNA-Seq analysis suggested that the expression of genes involved in NAD+ metabolism is altered in activated hepatic stellate cells (HSCs) compared to quiescent HSCs. NR inhibited the activation of HSCs in primary mouse and human HSCs. Indirect calorimetry showed that NR increased energy expenditure, likely by upregulation of β-oxidation in skeletal muscle and brown adipose tissue.

CONCLUSION

NR attenuated HSC activation, leading to reduced liver fibrosis in a diet-induced mouse model of liver fibrosis. The data suggest that NR may be developed as a potential preventative for human liver fibrosis.

In vitro inhibition of hepatic stellate cell activation by the autophagy-related lipid droplet protein ATG2A

Clinical studies have found that moderate intake of retinol or oleic acid can enlarge the lipid droplets of hepatic stellate cells and suppress their activation. However, the link between lipid droplets and cell activation is unknown. This study compared the dynamics of lipid droplet-associated protein expression between activated and reverted stellate cells. Reversion of the activated human stellate cell line LX-2 and inhibition of primary mouse stellate cell activation were induced by retinol or oleic acid, which resulted in larger lipid droplets and the downregulation of cell activation markers. Quantitative proteomics and immunoblotting were performed to compare lipid-droplet protein profiles between activated and reverted LX-2 cells. Compared to expression in activated cells, 50 lipid-droplet proteins were upregulated, whereas 28 were downregulated upon reversion. ATG2A was significantly enriched in lipid droplets of retinol/oleic acid-treated LX-2 cells and quiescent primary stellate cells. Reduced expression of α-SMA, increased expression of perilipin-3, enlarged lipid droplets, and suppression of autophagic flux were observed in ATG2A-deficient LX2 cells. Lipid-droplet protein profile changes during the reversion of activated stellate cells might provide new insights into the molecular mechanisms linking lipid droplets to liver fibrosis. ATG2A could represent a potential new drug target for hepatic fibrosis.