The Effects of Irisin on the Interaction between Hepatic Stellate Cell and Macrophage in Liver Fibrosis

The potential of flavonoids in hepatic fibrosis: A comprehensive review

BACKGROUND

Hepatic fibrosis is a pathophysiological process of extracellular matrix abnormal deposition induced by multiple pathogenic factors. Currently, there is still a lack of effective and non-toxic drugs for treating fibrosis in clinic. Flavonoids are polyphenolic compounds synthesized in plants and modern pharmacological studies confirmed flavonoids exhibit potent hepatoprotective effect.

PURPOSE

Summarize literature to elaborate the mechanism of HF and evaluate the potential of flavonoids in HF, aiming to provide a new perspective for future research.

METHODS

The literatures about hepatic fibrosis and flavonoids are collected via a series of scientific search engines including Google Scholar, Elsevier, PubMed, CNKI, WanFang, SciFinder and Web of Science database. The key words are "flavonoids", "hepatic fibrosis", "pharmacokinetic", "toxicity", "pathogenesis" "traditional Chinese medicine" and "mechanism" as well as combination application.

RESULTS

Phytochemical and pharmacological studies revealed that about 86 natural flavonoids extracted from Chinese herbal medicines possess significantly anti-fibrosis effect and the mechanisms maybe through anti-inflammatory, antioxidant, inhibiting hepatic stellate cells activation and clearing activated hepatic stellate cells.

CONCLUSIONS

This review summarizes the flavonoids which are effective in HF and the mechanisms in vivo and in vitro. However, fewer studies are focused on the pharmacokinetics of flavonoids in HF model and most studies are limited to preclinical studies, therefore there is no reliable data from clinical trials for the development of new drugs. Further in-depth research related it can be conducted to improve the bioavailability of flavonoids and serve the development of new drugs.

SKIL/SnoN attenuates TGF-β1/SMAD signaling-dependent collagen synthesis in hepatic fibrosis

The ski-related novel gene (SnoN), encoded by the SKIL gene, has been shown to negatively regulated transforming growth factor-β1 (TGF-β1) signaling pathway. However, the roles of SnoN in hepatic stellate cell (HSC) activation and hepatic fibrosis (HF) are still unclear. To evaluate the role of SnoN in HF, we combined bulk RNA sequencing analysis and single-cell RNA sequencing analysis to analyse patients with HF. The role of SKIL/SnoN was verified using liver samples from rat model transfected HSC-T6 and LX-2 cell lines. Immunohistochemistry, immunofluorescence, PCR, and western blotting techniques were used to demonstrate the expression of SnoN and its regulatory effects on TGF-β1 signaling in fibrotic liver tissues and cells. Furthermore, we constructed competitive endogenous RNA regulatory network and potential drug network associated with the SnoN gene. We identified SKIL gene as a differentially expressed gene in hepatic fibrosis. SnoN protein was found to be widely expressed in the cytoplasm of normal hepatic tissues, whereas it was almost absent in HF tissues. In the rat group subjected to bile duct ligation (BDL), SnoN protein expression decreased, while TGF-β1, collagen III, tissue inhibitor of metalloproteinase 1 (TIMP-1), and fibronectin levels increased. We observed the interaction of SnoN with p-SMAD2 and p-SMAD3 in the cytoplasm. Following SnoN overexpression, apoptosis of HSCs was promoted, and the expression of HF-associated proteins, including collagen I, collagen III, and TIMP-1, was reduced. Conversely, downregulation of SnoN inhibited HSC apoptosis, increased collagen III and TIMP-1 levels, and decreased matrix metalloproteinase 13 (MMP-13) expression. In conclusion, SnoN expression is downregulated in fibrotic livers, and could attenuate TGF-β1/SMADs signaling-dependent de-repression of collagen synthesis.

Potential role of irisin in digestive system diseases

Digestive system diseases (DSD) are very complex conditions that severely threaten human health. Therefore, there is an urgent need to develop new pharmacological treatment strategies. Irisin, a myokine discovered in 2012, is produced by fibronectin type III domain-containing protein 5 (FNDC5), which is a transmembrane protein. Irisin is involved in promoting the browning of white adipose tissue, the regulation of energy metabolism, and the improvement of insulin resistance. Irisin is also an essential mediator of the inflammatory response, oxidative stress, and cell apoptosis. Recent studies have proved that irisin concentration is altered in DSD and exerts pivotal effects on the initiation, progression, and prognosis of these diseases through various mechanisms. Therefore, studying the expression and function of irisin may have great significance for the diagnosis and treatment of DSD. Here, we focus on irisin and explore the multiple molecular pathways targeted by irisin therapy. This review indicates that irisin can serve as a diagnostic marker or potential therapeutic agent for DSD. DATA AVAILABILITY: Not applicable.

Matrix metalloproteinases induce extracellular matrix degradation through various pathways to alleviate hepatic fibrosis

Liver fibrosis is the common consequence of various chronic liver injuries and is mainly characterized by the imbalance between the production and degradation of extracellular matrix, which leads to the accumulation of interstitial collagen and other matrix components. Matrix metalloproteinases (MMPs) and their specific inhibitors, that is, tissue inhibitors of metalloproteinases (TIMPs), play a crucial role in collagen synthesis and lysis. Previous in vivo and in vitro studies of our laboratory found repressing extracellular matrix (ECM) accumulation by restoring the balance between MMPs and TIMPs can alleviate liver fibrosis. We conducted a review of articles published in PubMed and Science Direct in the last decade until February 1, 2023, which were searched for using these words "MMPs/TIMPs" and "Hepatic Fibrosis." Through a literature review, this article reviews the experimental studies of liver fibrosis based on MMPs/TIMPs, summarizes the components that may exert an anti-liver fibrosis effect by affecting the expression or activity of MMPs/TIMPs, and attempts to clarify the mechanism of MMPs/TIMPs in regulating collagen homeostasis, so as to provide support for the development of anti-liver fibrosis drugs. We found the MMP-TIMP-ECM interaction can result in better understanding of the pathogenesis and progression of hepatic fibrosis from a different angle, and targeting this interaction may be a promising therapeutic strategy for hepatic fibrosis. Additionally, we summarized and analyzed the drugs that have been found to reduce liver fibrosis by changing the ratio of MMPs/TIMPs, including medicine natural products.

The effect of sarcopenia and serum myokines on prognosis and survival in cirrhotic patients: a multicenter cross-sectional study

OBJECTIVE

Sarcopenia is one of the most significant contributors to morbidity in patients with chronic liver disease. Serum myokines are potential biomarkers for detecting early sarcopenia. We aimed to investigate the relationship between serum myokines and cirrhosis-related mortality in the early stages of the disease.

METHODS

In total, 262 patients and 50 healthy controls were enrolled in this study, which was designed as a multicenter cross-sectional study. At the beginning of the study, sarcopenia was defined by computed tomography scans using the third lumbar vertebra skeletal muscle index. Serum myostatin, irisin, and follistatin levels, nutritional status of the patients, and muscle strength as measured by the handgrip test were recorded. Cirrhosis-related mortality and overall survival were evaluated in the fourth year of the study as the second checkpoint of cross-sectional analysis.

RESULTS

A total of 145 (55.3%) patients were diagnosed with sarcopenia. Multivariate analysis revealed that low BMI, high levels of myostatin, and decreased irisin levels were independent predictors of sarcopenia. While serum irisin level was the most predictive parameter in terms of 4th-year cirrhosis-related mortality in the CHILD A group, serum myostatin levels were found more indicative in the CHILD BC group regardless of sarcopenia status ( P < 0.001).

CONCLUSION

Serum myostatin levels predict sarcopenia in all stages of cirrhosis. Serum irisin levels can also be used as a potential biomarker to predict both treatable sarcopenia and cirrhosis-related mortality in CHILD A patients.