Emerging drugs for the treatment of hepatic fibrosis on nonalcoholic steatohepatitis

INTRODUCTION

Approved drug therapies for nonalcoholic steatohepatitis (NASH) are lacking, for which various agents are currently being tested in clinical trials. Effective drugs for liver fibrosis, the factor most associated with prognosis in NASH, are important.

AREAS COVERED

This study reviewed the treatment of NASH with a focus on the effects of existing drugs and new drugs on liver fibrosis.

EXPERT OPINION

Considering the complex pathophysiology of fibrosis in NASH, drug therapy may target multiple pathways. The method of assessing fibrosis is important when considering treatment for liver fibrosis in NASH. The Food and Drug Administration considers an important fibrosis endpoint to be histological improvement in at least one fibrosis stage while preventing worsening of fatty hepatitis. To obtain approval as a drug for NASH, efficacy needs to be demonstrated on endpoints such as liver-related events and myocardial infarction. Among the current therapeutic agents for NASH, thiazolidinedione, sodium-glucose co-transporter 2, and selective peroxisome proliferator-activated receptors α modulator have been reported to be effective against fibrosis, although further evidence is required. The effects of pan-peroxisome proliferator-activated receptors, obeticholic acid, and fibroblast growth factor-21 analogs on liver fibrosis in the development stage therapeutics for NASH are of particular interest.

Targeting HSP47 and HSP70: promising therapeutic approaches in liver fibrosis management

Liver fibrosis is a liver disease in which there is an excessive buildup of extracellular matrix proteins, including collagen. By regulating cytokine production and the inflammatory response, heat shock proteins (HSPs) contribute significantly to a wider spectrum of fibrotic illnesses, such as lung, liver, and idiopathic pulmonary fibrosis by aiding in the folding and assembly of freshly synthesized proteins, HSPs serve as chaperones. HSP70 is one of the key HSPs in avoiding protein aggregation which induces its action by sending unfolded and/or misfolded proteins to the ubiquitin–proteasome degradation pathway and antagonizing influence on epithelial-mesenchymal transition. HSP47, on the other hand, is crucial for boosting collagen synthesis, and deposition, and fostering the emergence of fibrotic disorders. The current review aims to provide light on how HSP70 and HSP47 affect hepatic fibrogenesis. Additionally, our review looks into new therapeutic approaches that target HSP70 and HSP47 and could potentially be used as drug candidates to treat liver fibrosis, especially in cases of comorbidities.

CyPA interacts with SERPINH1 to promote extracellular matrix production and inhibit epithelial-mesenchymal transition of trophoblast via enhancing TGF-β/Smad3 pathway in preeclampsia

We previously reported that cyclophilin A (CyPA) production is upregulated in preeclampsia (PE). Moreover, CyPA is known to induce PE-like features in pregnant mice and impair trophoblast invasiveness. In this study, we further illustrated the role of CyPA in PE. RNA-seq analysis, RT-qPCR, immunohistochemical (IHC) staining, and western blotting of mouse placentae revealed that CyPA increased the levels of extracellular matrix (ECM) proteins, such as collagen I and fibronectin, and activated the TGF-β/Smad3 signaling pathway. Additionally, CyPA inhibited the expression of genes involved in epithelial-mesenchymal transition (EMT) (e.g., E-cadherin, N-cadherin, and vimentin) in mouse placentae. We then constructed stable overexpressing and knock-down CyPA cell models (using HTR8/SVneo cells) to clarify the molecular mechanism. We found that CyPA regulated the levels of ECM-related proteins and the EMT process through the TGF-β/Smad3 pathway. We also identified SERPINH1 as a putative CyPA-binding protein, using liquid chromatography-electrospray mass spectrometry (LC-MS)/MS. SERPINH1 was found to be upregulated in the placentae of PE. Silencing SERPINH1 expression reversed the upregulation of ECM proteins and inhibition of the EMT process induced by the overexpression of CyPA. These findings revealed the functions of CyPA in the impaired invasiveness of trophoblasts in PE and indicated that CyPA and SERPINH1 may represent promising targets for the treatment of PE.

Echinococcus multilocularis drives the polarization of macrophages by regulating the RhoA-MAPK signaling pathway and thus affects liver fibrosis

Echinococcus multilocularis is a small parasite that causes alveolar echinococcosis. It primarily induces liver disorder, such as liver fibrosis and even liver cancer, which severely endangers human lives. This study aims to explore the efficacy of Echinococcus multilocularis soluble antigen in preventing and alleviating alveolar echinococcosis-induced liver fibrosis and determine the underlying mechanism. We first identified the optimal dose and time of Echinococcus multilocularis soluble antigen. The protein levels of key genes in the RhoA-MAPK signaling pathway were remarkably upregulated in RAW264.7 and Ana-1 cells induced with 80 μg/mL Echinococcus multilocularis soluble antigen for 8 h. Interestingly, the upregulated expression levels were remarkably reversed by the RhoA, JNK, ERK, or p38 inhibitor, confirming the significance of the RhoA-MAPK signaling pathway. In addition, the relative contents of M2 polarization markers IL-10 and Arg-1 in macrophages induced with 80 μg/mL Echinococcus multilocularis soluble antigen for 8 h increased, whereas those of M1 polarization markers IL-12 and NOS-2 decreased. Mouse hepatic stellate cells were the key components of the hepatocellular carcinoma tumor microenvironment. Hepatic stellate cells were activated by Echinococcus multilocularis soluble antigen and transformed into the morphology of myofibroblasts in response to liver disorders. By detecting the marker of myofibroblast formation, RhoA inhibitor remarkably reduced the positive expression of α-SMA in mouse hepatic stellate cells induced with Echinococcus multilocularis soluble antigen. Therefore, Echinococcus multilocularis soluble antigen remarkably activated the RhoA-MAPK pathways in macrophages, further inducing the polarization of macrophages and ultimately causing liver fibrosis. Hypothesis: We hypothesize that infection with Echinococcus multilocularis activates the RhoA-MAPK signaling pathway and subsequently induces macrophage polarization to promote hepatic stellate cells activation leading to liver fibrosis. Aims: To investigate the mechanism by which soluble antigen of Echinococcus multilocularis affects liver fibrosis through the RhoA-MAPK pathway driving polarization of macrophages. Goals: To identify new pathways of intervention and drug targets for the regulation of macrophage polarity phenotype switching and the attenuation or inhibition of the development and treatment of liver fibrosis caused by Echinococcus multilocularis infection.

Silencing Heat Shock Protein 47 (HSP47) in Fibrogenic Precision-Cut Lung Slices: A Surprising Lack of Effects on Fibrogenesis?

Idiopathic pulmonary fibrosis (IPF) is a chronic disease that is characterized by the excessive deposition of scar tissue in the lungs. As currently available treatments are unable to restore lung function in patients, there is an urgent medical need for more effective drugs. Developing such drugs, however, is challenging because IPF has a complex pathogenesis. Emerging evidence indicates that heat shock protein 47 (HSP47), which is encoded by the gene Serpinh1, may be a suitable therapeutic target as it is required for collagen synthesis. Pharmacological inhibition or knockdown of HSP47 could therefore be a promising approach to treat fibrosis. The objective of this study was to assess the therapeutic potential of Serpinh1-targeting small interfering RNA (siRNA) in fibrogenic precision-cut lung slices prepared from murine tissue. To enhance fibrogenesis, slices were cultured for up to 144 h with transforming growth factor β1. Self-deliverable siRNA was used to knockdown mRNA and protein expression, without affecting the viability and morphology of slices. After silencing HSP47, only the secretion of fibronectin was reduced while other aspects of fibrogenesis remained unaffected (e.g., myofibroblast differentiation as well as collagen secretion and deposition). These observations are surprising as others have shown that Serpinh1-targeting siRNA suppressed collagen deposition in animals. Further studies are therefore warranted to elucidate downstream effects on fibrosis upon silencing HSP47.

A perspective on RNA interference-based therapeutics for metabolic liver diseases

Introduction: Therapeutic oligonucleotides have emerged as a promising new class of drug that could silence undruggable targets; they can potentially treat metabolic liver diseases such as nonalcoholic fatty liver disease (NAFLD), hereditary hemochromatosis and alpha 1 antitrypsin deficiency.Areas covered: This article illuminates the mechanism of action of, and drug delivery approaches for therapeutic oligonucleotides such as antisense oligonucleotides (ASOs), short interfering RNAs (siRNAs), and MicroRNAs (miRs). We reveal why the liver is the ideal organ for therapeutic oligonucleotides, discuss its unique architecture, and shed light on those susceptible molecular targets that can be modulated. We also examine preclinical and clinical data on the utility of oligonucleotides in silencing the expression of genes responsible for metabolic liver diseases.Expert opinion: The liver has numerous susceptible molecular therapeutic targets; hence, metabolic liver diseases can be treated effectively by modulating these targets via novel therapeutic oligonucleotides. Undoubtedly, these exciting developments integrate well with precision medicine progress. Specific therapeutic oligonucleotides can be designed based on the exact underlying molecular mechanism of the disease. So, there is a justification for furthering the development of therapeutic oligonucleotides for metabolic liver diseases. Safety concerns such as immunogenicity and off-target effects will however require careful monitoring.

The role of heat shock proteins in the regulation of fibrotic diseases

Heat shock proteins (HSPs) are key players to restore cell homeostasis and act as chaperones by assisting the folding and assembly of newly synthesized proteins and preventing protein aggregation. Recently, evidence has been accumulating that HSPs have been proven to have other functions except for the classical molecular chaperoning in that they play an important role in a wider range of fibrotic diseases via modulating cytokine induction and inflammation response, including lung fibrosis, liver fibrosis, and idiopathic pulmonary fibrosis. The recruitment of inflammatory cells, a large number of secretion of pro-fibrotic cytokines such as transforming growth factor-β1 (TGF-β1) and increased apoptosis, oxidative stress, and proteasomal system degradation are all events occurring during fibrogenesis, which might be associated with HSPs. However, their role on fibrotic process is not yet fully understood. In this review, we discuss new discoveries regarding the involvement of HSPs in the regulation of organ and tissue fibrosis, and note recent findings suggesting that HSPs may be a promising therapeutic target for improving the current frustrating outcome of fibrotic disorders.

Xiaochaihu decorction relieves liver fibrosis caused by Schistosoma japonicum infection via the HSP47/TGF-β pathway

Background

Hepatic fibrosis caused by chronic infection with Schistosoma japonica remains a serious public health problem in the world. Symptoms include inflammation, liver granuloma and fibrosis, whilst treatment options are still limited. This study aims to investigate whether and how traditional Chinese medicine Xiaochaihu decoction (XCH) could mitigate liver fibrosis caused by S. japonicum infection.

Methods

BALB/c mice were infected with S. japonicum cercariae and treated with XCH for 16 weeks. Liver pathological changes were assessed by H&E and Masson staining. NIH3T3 and Raw264.7 cells were treated with S. japonicum egg antigens with or without XCH treatment. Quantitative real-time PCR, western blot, immunfluorescence and ELISA were performed to determine the changes of levels of fibrogenic markers.

Results

XCH protected mouse liver from injuries and fibrosis caused by S. japonicum infection and considerably reduced egg burden in a dose-dependent manner. Infection with S. japonicum caused elevation of serum ALT, AST, ALP, HA and PIIINP levels and reduction of ALB and GLOB levels, which was markedly suppressed by XCH. The upregulation of TGF-β1, Hsp47, α-SMA, Col1A1 and Col3A1 in S. japonicum-infected mouse liver was also significantly inhibited by XCH. Schistosoma japonicum egg antigens promoted the expression of Hsp47, TGF-β1, Timp-1, α-SMA, Col1A1 and Col3A1 in NIH3T3 cells, and TGF-β1, CTGF, IL-13, IL-17 and IL-6 in Raw264.7 cells, which was inhibited by XCH, LY2157299 and shRNA-Hsp47.

Conclusions

These results demonstrated that the hepatic protective effects of Xiaochaihu decoction were mediated by HSP47/TGF-β axis.

The heat shock protein 47 as a potential biomarker and a therapeutic agent in cancer research

Heat shock protein 47 (HSP47) is an important chaperone required for the correct folding and secretion of collagen. Several studies revealed that HSP47 has a role in numerous steps of collagen synthesis, preventing procollagen aggregation and inducing hydroxylation of proline and lysine residues. HSP47 is encoded by the SERPINH1 gene, which is located on chromosome 11q13.5, one of the most frequently amplified regions in human cancer. The altered expression levels of HSP47 have been correlated with several types of cancer, such as cervical, breast, pancreatic and gastric cancers. Studies have shown that HSP47 promotes tumor angiogenesis, growth, migration and metastatic capacity. In this review, we highlight the fundamental aspects of the interaction between HSP47 and collagen and the recent discoveries of the role of this chaperone in different types of malignant neoplasias. We also discuss recent treatments using HSP47 as a therapeutic target, and present evidences that HSP47 is an essential protein for cancer biology and a potential molecular target for chemotherapy.