A Disintegrin and Metalloprotease with Thrombospondin Motif 2 May Contribute to Cirrhosis in Humans through the Transforming Growth Factor-β/SMAD Pathway

The Mechanism and Role of ADAMTS Protein Family in Osteoarthritis

Osteoarthritis (OA) is a principal cause of aches and disability worldwide. It is characterized by the inflammation of the bone leading to degeneration and loss of cartilage function. Factors, including diet, age, and obesity, impact and/or lead to osteoarthritis. In the past few years, OA has received considerable scholarly attention owing to its increasing prevalence, resulting in a cumbersome burden. At present, most of the interventions only relieve short-term symptoms, and some treatments and drugs can aggravate the disease in the long run. There is a pressing need to address the safety problems due to osteoarthritis. A disintegrin-like and metalloprotease domain with thrombospondin type 1 repeats (ADAMTS) metalloproteinase is a kind of secretory zinc endopeptidase, comprising 19 kinds of zinc endopeptidases. ADAMTS has been implicated in several human diseases, including OA. For example, aggrecanases, ADAMTS-4 and ADAMTS-5, participate in the cleavage of aggrecan in the extracellular matrix (ECM); ADAMTS-7 and ADAMTS-12 participate in the fission of Cartilage Oligomeric Matrix Protein (COMP) into COMP lyase, and ADAMTS-2, ADAMTS-3, and ADAMTS-14 promote the formation of collagen fibers. In this article, we principally review the role of ADAMTS metalloproteinases in osteoarthritis. From three different dimensions, we explain how ADAMTS participates in all the following aspects of osteoarthritis: ECM, cartilage degeneration, and synovial inflammation. Thus, ADAMTS may be a potential therapeutic target in osteoarthritis, and this article may render a theoretical basis for the study of new therapeutic methods for osteoarthritis.

Molecular Crosstalk between the Hepatitis C Virus and the Extracellular Matrix in Liver Fibrogenesis and Early Carcinogenesis

Simple Summary

In the era of direct-acting antivirals against the hepatitis C virus (HCV), curing chronic hepatitis C has become a reality. However, while replicating chronically, HCV creates a peculiar state of inflammation and oxidative stress in the infected liver, which fuels DNA damage at the onset of HCV-induced hepatocellular carcinoma (HCC). This cancer, the second leading cause of death by cancer, remains of bad prognosis when diagnosed. This review aims to decipher how HCV durably alters elements of the extracellular matrix that compose the liver microenvironment, directly through its viral proteins or indirectly through the induction of cytokine secretion, thereby leading to liver fibrosis, cirrhosis, and, ultimately, HCC.

Abstract

Chronic infection by the hepatitis C virus (HCV) is a major cause of liver diseases, predisposing to fibrosis and hepatocellular carcinoma. Liver fibrosis is characterized by an overly abundant accumulation of components of the hepatic extracellular matrix, such as collagen and elastin, with consequences on the properties of this microenvironment and cancer initiation and growth. This review will provide an update on mechanistic concepts of HCV-related liver fibrosis/cirrhosis and early stages of carcinogenesis, with a dissection of the molecular details of the crosstalk during disease progression between hepatocytes, the extracellular matrix, and hepatic stellate cells.

Serum thrombospondin 2 is a novel predictor for the severity in the patients with NAFLD

AIM

Thrombospondins are a family of multidomain and secretory glycoproteins. Among them, thrombospondin 2 (TSP2) encoded by TSP2 gene has been reported to be involved in various functions such as collagen/fibrin formation, maintenance of normal blood vessel density and cell adhesion properties. Microarray analyses ranked TSP2 as one of the most highly up-regulated genes in the fibrotic liver in patients with non-alcoholic fatty liver disease (NAFLD). Since TSP2 possesses unique properties as a secretory protein, we hypothesized that hepatic TSP2 gene expression levels would be reflected in serum TSP2 levels. In this study, we examined the relationship between serum TSP2 concentrations and clinicopathological findings in NAFLD patients.

METHODS

One hundred and thirty NAFLD patients who had undergone liver biopsy between 2009 and 2015 were retrospectively enrolled. Serum samples were collected at the time of biopsy, and TSP2 was measured by enzyme immunoassays.

RESULTS

Serum TSP2 levels moderately correlated with ballooning (r = 0.56, P < .001) and fibrosis stage (r = 0.53, P < .001). The AUC values of TSP2 for predicting mild fibrosis (≧F1), moderate fibrosis (≧F2) and severe fibrosis (≧F3) were 0.73, 0.76 and 0.82 respectively. Additionally, NAFLD activity score (NAS) correlated best with TSP2 (r = 0.52, P < .001) compared to conventional NAFLD-related biomarkers, such as cytokeratin 18 M30, hyaluronic acid, type IV collagen 7S, APRI and FIB-4 index.

CONCLUSION

Serum TSP2 levels reflected hepatocyte ballooning, fibrosis and NAS in NAFLD patients. For clinical application of serum TSP2 as a predictor of NAFLD histological activity, additional validation and mechanistic investigations are required.

Transcriptomic Bioinformatic Analyses of Atria Uncover Involvement of Pathways Related to Strain and Post-translational Modification of Collagen in Increased Atrial Fibrillation Vulnerability in Intensely Exercised Mice

Atrial Fibrillation (AF) is the most common supraventricular tachyarrhythmia that is typically associated with cardiovascular disease (CVD) and poor cardiovascular health. Paradoxically, endurance athletes are also at risk for AF. While it is well-established that persistent AF is associated with atrial fibrosis, hypertrophy and inflammation, intensely exercised mice showed similar adverse atrial changes and increased AF vulnerability, which required tumor necrosis factor (TNF) signaling, even though ventricular structure and function improved. To identify some of the molecular factors underlying the chamber-specific and TNF-dependent atrial changes induced by exercise, we performed transcriptome analyses of hearts from wild-type and TNF-knockout mice following exercise for 2 days, 2 or 6 weeks of exercise. Consistent with the central role of atrial stretch arising from elevated venous pressure in AF promotion, all 3 time points were associated with differential regulation of genes in atria linked to mechanosensing (focal adhesion kinase, integrins and cell-cell communications), extracellular matrix (ECM) and TNF pathways, with TNF appearing to play a permissive, rather than causal, role in gene changes. Importantly, mechanosensing/ECM genes were only enriched, along with tubulin- and hypertrophy-related genes after 2 days of exercise while being downregulated at 2 and 6 weeks, suggesting that early reactive strain-dependent remodeling with exercise yields to compensatory adjustments. Moreover, at the later time points, there was also downregulation of both collagen genes and genes involved in collagen turnover, a pattern mirroring aging-related fibrosis. By comparison, twofold fewer genes were differentially regulated in ventricles vs. atria, independently of TNF. Our findings reveal that exercise promotes TNF-dependent atrial transcriptome remodeling of ECM/mechanosensing pathways, consistent with increased preload and atrial stretch seen with exercise. We propose that similar preload-dependent mechanisms are responsible for atrial changes and AF in both CVD patients and athletes.

Polydatin inhibits ZEB1-invoked epithelial-mesenchymal transition in fructose-induced liver fibrosis

High fructose intake is a risk factor for liver fibrosis. Polydatin is a main constituent of the rhizome of Polygonum cuspidatum, which has been used in traditional Chinese medicine to treat liver fibrosis. However, the underlying mechanisms of fructose-driven liver fibrosis as well as the actions of polydatin are not fully understood. In this study, fructose was found to promote zinc finger E-box binding homeobox 1 (ZEB1) nuclear translocation, decrease microRNA-203 (miR-203) expression, increase survivin, activate transforming growth factor β1 (TGF-β1)/Smad signalling, down-regulate E-cadherin, and up-regulate fibroblast specific protein 1 (FSP1), vimentin, N-cadherin and collagen I (COL1A1) in rat livers and BRL-3A cells, in parallel with fructose-induced liver fibrosis. Furthermore, ZEB1 nuclear translocation-mediated miR-203 low-expression was found to target survivin to activate TGF-β1/Smad signalling, causing the EMT in fructose-exposed BRL-3A cells. Polydatin antagonized ZEB1 nuclear translocation to up-regulate miR-203, subsequently blocked survivin-activated TGF-β1/Smad signalling, which were consistent with its protection against fructose-induced EMT and liver fibrosis. These results suggest that ZEB1 nuclear translocation may play an essential role in fructose-induced EMT in liver fibrosis by targeting survivin to activate TGF-β1/Smad signalling. The suppression of ZEB1 nuclear translocation by polydatin may be a novel strategy for attenuating the EMT in liver fibrosis associated with high fructose diet.

Hypoxia causes important changes of extracellular matrix biomarkers and ADAMTS proteinases in the adriamycin-induced renal fibrosis model

AIM

Renal fibrosis is a common cause of renal dysfunction with chronic kidney diseases. This process is characterized by excessive production of extracellular matrix (ECM) or inhibition of ECM degradation. A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) proteinases, which are widely presented in mammals, have very critical roles in ECM remodelling. We aimed to study the role of ADAMTS proteinases and some of the ECM markers in the pathogenesis of renal fibrosis and to investigate the effects of hypoxia on these biomarkers.

METHODS

In addition to the control group, Adriamycin (ADR) treated rats were divided into four groups as ADR, sham and two hypoxia groups. Renal nephropathy was assessed biochemical assays, pathological and immunohistochemical staining methods. The expression of ADAMTSs and mRNA were determined using Western blotting and real-time PCR, respectively.

RESULTS

Renal dysfuntion and tissue damage in favour of ECM accumulation and renal fibrosis were observed in the ADR group. This was approved by remarkable changes in the expression of ADAMTS such as increased ADAMTS-1, -12 and -15. In addition, it was found that hypoxia and duration of hypoxia enhanced markers of tubulointerstitial fibrosis in the rat kidney tissues. Also, expression differences especially in ADAMTS-1, -6 and -15 were observed in the hypoxia groups. The variable and different expression patterns of ADAMTS proteinases in the ADR-induced renal fibrosis suggest that ADAMTS family members are involved in the development and progression of fibrosis.

CONCLUSION

The expression changes of ADAMTS proteinases in kidney and association with hypoxia have potential clues to contribute to the early diagnosis and treatment options of renal fibrosis.

Cardiac fibrosis in regenerative medicine: destroy to rebuild

The major limitations for cardiac regeneration in patients after myocardial infarction (MI) are the wide loss of cardiomyocytes and the adverse structural alterations of extracellular matrix (ECM). Cardiac fibroblast differentiation into myofibroblasts (MFB) leads to a huge deposition of ECM and to the subsequent loss of ventricular structural integrity. All these molecular events depict the fundamental features at the basis of the post-MI fibrosis and deserve in depth cellular and molecular studies to fill the gap in the clinical practice. Indeed, to date, there are no effective therapeutic approaches to limit the post-MI massive fibrosis development. In this review we describe the involvement of integrins and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)/ADAMTS-like (ADAMTSL) proteins in cardiac reparative pro-fibrotic response after MI, proposing some of them as novel potential pharmacological tools.

Selenium modulates MMP2 expression through the TGFβ1/Smad signalling pathway in human umbilical vein endothelial cells and rabbits following lipid disturbance

BACKGROUND

A high-fat diet is a major risk factor for coronary heart diseases. Matrix metalloprotease (MMP) expression is changed in many cardiovascular diseases. Selenium, which is an important trace element in animals, has a close relationship with cardiovascular diseases. The TGFβ1/Smad signalling pathway is ubiquitous in diverse tissues and cells, and it is also associated with the occurrence and development of cardiovascular diseases. Therefore, in this study, we aimed to determine selenium's effect on lipid metabolism, atherosclerotic plaque formation, and MMP2 expression, as well as the underlying functional mechanism.

METHODS AND RESULTS

In vivo tests: 24 male New Zealand white rabbits were randomly divided into 4 groups: regular diet, high-fat diet, high-fat diet+selenium and regular diet+selenium groups. The high-fat diet induced the lipid disturbances of rabbits at week 12. Selenium supplementation lowered total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and triglyceride (TG) levels (p<0.01). Selenium supplementation also suppressed MMP2 over-expression in thoracic aortas. In vitro tests: Human umbilical vein endothelial cells (HUVECs) were treated with different concentrations of selenium or ox-LDL. Ox-LDL promoted MMP2 expression by increasing TGFβ1, pSmad2, pSmad3 and Smad3 expression (p<0.01). Selenium attenuated MMP2 over-expression by regulating the TGFβ1/Smad signalling pathway.

CONCLUSIONS

Selenium suppressed high-fat diet-induced MMP2 over-expression in vivo by improving lipid metabolism. In vitro, selenium attenuated MMP2 over-expression through the TGFβ1/Smad signalling pathway.

Estradiol attenuates the TGF-β1-induced conversion of primary TAFs into myofibroblasts and inhibits collagen production and myofibroblast contraction by modulating the Smad and Rho/ROCK signaling pathways

The transformation of tunica albuginea-derived fibroblasts (TAFs) into myofibroblasts plays an important role in the pathological progress of Peyronie's disease (PD). However, no treatment which addresses this transformation is currently available. Estrogen has been shown to inhibit the progression of fibrosis in a number of fibrotic diseases. The aim of this study was to determine whether estrogen [17β‑estradiol (E2)] suppresses the diffentiation of primary rat TAFs into myofibroblasts in vitro. TAFs obtained from male Sprague‑Dawley rats were stimulated with either transforming growth factor‑β1 (TGF‑β1) or E2. Western blot analysis and immunofluorescence staining were used to assess changes in the expression levels of α‑smooth muscle actin (αSMA). The expression levels of additional proteins (GAPDH, p‑Smad2, Smad2, Smad4, RhoA, Rac1, ROCK1 and ROCK2) were also measured by western blot analysis. We used collagen gel assays to assess cell contractility. Additionally, the concentration of hydroxyproline in the TAF cell culture medium was detected using commercially available kits. We found that E2 reduced αSMA expression which was induced by TGF‑β1. E2 also suppressed the TGF‑β1‑induced increase in the concentration of hydroxyproline (a marker of collagen) in addition to suppressing the contraction of TAFs. The key processes affected by TGF‑β1 treatment included the phosphorylation of Smad2, ras homolog gene family, member A (RhoA) and Rho‑associated, coiled-coil containing protein kinase 2 (ROCK2); this increase in phosphorylation was inhibited by treatment with E2. Collectively, these results demonstrate that by modulating the activation of the TGF‑β1‑Smad and RhoA‑ROCK2 signaling pathways, E2 inhibited the transformation of TAFs into myofibroblasts, decreased the expression of collagen and suppressed the contraction of myofibroblasts in response to TGF-β1 stimulation.

Modulation of IKKβ/NF-κB and TGF-β1/Smad via Fuzheng Huayu recipe involves in prevention of nutritional steatohepatitis and fibrosis in mice

OBJECTIVES

Fuzheng Huayu recipe (FZHY) exerts significant protective effects against liver fibrosis by strengthening the body's resistance and removing blood stasis. However, the molecular mechanisms through which FZHY affects liver fibrosis are still unclear. In this study, we examined the expression levels of factors involved in the inhibitor κB kinase-β (IKK-β)/nuclear factor-κB (NF-κB) and transforming growth factor beta 1 (TGF-β1)/Smad signaling pathways to elucidate whether FZHY could attenuate nutritional steatohepatitis and fibrosis in mice.

MATERIALS AND METHODS

C57BL/6J mice were fed with methionine-choline deficient (MCD) diet for 8 weeks to induce fibrotic steatohepatitis. FZHY and/or heme oxygenase-1 (HO-1) chemical inducer (hemin) were administered to mice. The effects of FZHY alone and in combination with hemin were assessed by comparing the severity of hepatic injury, activation of hepatic stellate cells (HSCs), and the expression of oxidative stress, inflammation and fibrogenesis related genes.

RESULTS

Administration of FZHY, hemin and FZHY plus hemin significantly ameliorated liver injury. Additionally, our analysis indicated that administration of these agents significantly attenuated oxidative stress, downregulated the expression of pro-inflammatory and pro-fibrotic genes, including IKK-β, NF-κB, monocyte chemoattractant protein-1 (MCP-1), α-smooth muscle actin (α-SMA), TGF-β1, Smad3 and Smad4, and upregulated the expression of the antifibrogenic gene Smad7 (P< 0.001).

CONCLUSION

FZHY-containing therapies prevented nutritional steatohepatitis and fibrosis through modulating the expression of factors associated with the IKKβ/NF-κB and TGF-β1/Smad signaling pathways and oxidative stress related genes.

The evolutionary conservation of the A Disintegrin-like and Metalloproteinase domain with Thrombospondin-1 motif metzincins across vertebrate species and their expression in teleost zebrafish

Background

The A Disintegrin-like and Metalloproteinase domain with Thrombospondin-1 motifs (ADAMTS) enzymes comprise 19 mammalian zinc-dependent metalloproteinases (metzincins) with homologues in a wide range of invertebrates. ADAMTS enzymes have a broad range of functions in development and diseases due to their extracellular matrix remodelling activity. Here, we report a detailed characterisation of their evolutionary conservation across vertebrates.

Results

Using bioinformatics complemented with de novo sequencing, gene sequences for ADAMTS enzymes were obtained from a variety of organisms. Detailed evolutionary analyses revealed a high level of conservation across vertebrates with evidence of ADAMTS gene expansion during two rounds of whole genome duplication (WGD) in vertebrates, while tandem duplication events and gene loss were also apparent. However, the additional round of teleost-specific WGD did not have a significant effect on ADAMTS gene family members suggesting their conserved roles have remained constant in teleost fish. Quantitative reverse-transcriptase polymerase chain reaction analysis revealed dynamic expression of adamts genes throughout zebrafish embryonic development reflecting the key conserved roles they play in vertebrate embryogenesis. Notably, several adamts mRNAs were maternally expressed with a dramatic increase in mRNA levels coinciding with zygotic expression and organogenesis. Broad adamts mRNA expression was also demonstrated in several adult organs indicating potential roles in adult homeostasis.

Conclusions

Our data highlight the evolution of the ADAMTS gene family through duplication processes across metazoans supplemented by a burst of amplification through vertebrate WGD events. It also strongly posits the zebrafish as a potential model species to further elucidate the function of ADAMTS enzymes during vertebrate development.

Electronic supplementary material

The online version of this article (doi:10.1186/s12862-015-0281-9) contains supplementary material, which is available to authorized users.