Matrilysin (MMP-7) is a major matrix metalloproteinase upregulated in biliary atresia-associated liver fibrosis

Matrix Metalloproteinases (MMPs) in Liver Diseases

Matrix metalloproteinases (MMPs) are proteinases capable of degrading components of the extracellular matrix and numerous nonmatrix proteins. MMPs along with tissue inhibitors of MMPs, have been implicated in the pathogenesis of liver diseases. Although, the precise mechanism-of-actions of MMPs in various liver related disorders is largely unknown, however, data from diverse experimental models indicate that these proteinases influence cellular activities including proliferation and survival, gene expression, as well as multiple aspects of inflammation. Hence, MMP's are likely key players in the outcomes related to liver disease.

Forkhead box A3 attenuated the progression of fibrosis in a rat model of biliary atresia

Biliary atresia is a rare, devastating disease of infants where a fibroinflammatory process destroys the bile ducts, leading to fibrosis and biliary cirrhosis, and death if untreated. The cause and pathogenesis remain largely unknown. We tried to investigate factors involved in biliary atresia, especially forkhead box A3 (Foxa3), which might exert a role in the treatment of liver disease. We used RNA sequencing to sequence the whole transcriptomes of livers from six biliary atresia and six choledochal cysts patients. Then, we employed a rat disease model by bile duct ligation (BDL) and adenovirus transduction to address the function of Foxa3 in biliary atresia. We found that tight junction, adherence junction, cell cycle, apoptosis, chemokine singling, VEGF and MAPK signaling pathways were enriched in biliary atresia livers. We showed that Foxa3 expression was notably decreased in liver samples from biliary atresia patients. More importantly, we found that its lower expression predicted a poorer overall survival of biliary atresia patients. Rats that received BDL surgery and Foxa3 expression adenovirus resulted in a significant decrease in the deposition of collagen, and expression of profibrotic cytokines (transforming growth factor-β and connective tissue growth factor) and fibrosis markers (α-smooth muscle actin, collagen I and collagen III), as compared with rats that received BDL surgery and control adenovirus. Our data suggested a protection role for Foxa3 during the progression of liver fibrosis in biliary atresia, and thereby supported increasing Foxa3 as a targeted treatment strategy.

Matrix Metalloproteinases-7 and Kidney Fibrosis

Matrix metalloproteinase-7 (MMP-7) is a secreted zinc- and calcium-dependent endopeptidase that degrades a broad range of extracellular matrix substrates and additional substrates. MMP-7 playsa crucial role in a diverse array of cellular processes and appears to be a key regulator of fibrosis in several diseases, including pulmonary fibrosis, liver fibrosis, and cystic fibrosis. In particular, the relationship between MMP-7 and kidney fibrosis has attracted significant attention in recent years. Growing evidence indicates that MMP-7 plays an important role in the pathogenesis of kidney fibrosis. Here, we summarize the recent progress in the understanding of the role of MMP-7 in kidney fibrosis. In particular, we discuss how MMP-7 contributes to kidney fibrotic lesions via the following three pathways: epithelial-mesenchymal transition (EMT), transforming growth factor-beta (TGF-β) signaling, and extracellular matrix (ECM) deposition. Further dissection of the crosstalk among and regulation of these pathways will help clinicians and researchers develop effective therapeutic approaches for treating chronic kidney disease.

Multiplex Serum Protein Analysis Identifies Novel Biomarkers of Advanced Fibrosis in Patients with Chronic Liver Disease with the Potential to Improve Diagnostic Accuracy of Established Biomarkers

Background and Aims

Non-invasive markers of liver fibrosis are urgently required, especially for use in non-specialist settings. The aim of this study was to identify novel serum biomarkers of advanced fibrosis.

Methods

We performed an unbiased screen of 120 serum analytes including cytokines, chemokines and proteases in 70 patients (35 without fibrosis, 35 with cirrhosis on biopsy), and selected a panel of 44 candidate biomarkers, which were subsequently measured in a mixed-etiology cohort of 432 patients with known serum HA, PIIINP and TIMP1 (which comprise the validated Enhanced Liver Fibrosis (ELF) test). Multivariate logistic regression modelling was used to generate models for the prediction of advanced or significant fibrosis (METAVIR ≥F3 and ≥F2, respectively); in addition to identifying biomarkers of disease activity and steatohepatitis.

Results

Seventeen analytes were significantly differentially expressed between patients with no advanced fibrosis and patients with advanced fibrosis, the most significant being hyaluronic acid (HA) and matrix metalloproteinase (MMP) 7 (p = 2.9E-41 and p = 1.0E-26, respectively). The optimal model for the prediction of advanced fibrosis comprised HA, MMP7, MMP1, alphafetoprotein (AFP) and the AST to platelet ratio index (APRI). We demonstrate enhanced diagnostic accuracy (AUROC = 0.938) compared to a model comprising HA, PIIINP and TIMP1 alone (ELF) (AUROC = 0.898, p<0.0001, De Long’s test).

Conclusions

We have identified novel serum biomarkers of advanced liver fibrosis, which have the potential to enhance the diagnostic accuracy of established biomarkers. Our data suggest MMP7 is a valuable indicator of advanced fibrosis and may play a role in liver fibrogenesis.

Novel Role for Matrix Metalloproteinase 9 in Modulation of Cholesterol Metabolism

Background

The development of atherosclerosis is strongly linked to disorders of cholesterol metabolism. Matrix metalloproteinases (MMPs) are dysregulated in patients and animal models with atherosclerosis. Whether systemic MMP activity influences cholesterol metabolism is unknown.

Methods and Results

We examined MMP‐9–deficient (Mmp9^−/−) mice and found them to have abnormal lipid gene transcriptional responses to dietary cholesterol supplementation. As opposed to Mmp9^+/+ (wild‐type) mice, Mmp9^−/− mice failed to decrease the hepatic expression of sterol regulatory element binding protein 2 pathway genes, which control hepatic cholesterol biosynthesis and uptake. Furthermore, Mmp9^−/− mice failed to increase the expression of genes encoding the rate‐limiting enzymes in biliary cholesterol excretion (eg, Cyp7a and Cyp27a). In contrast, MMP‐9 deficiency did not impair intestinal cholesterol absorption, as shown by the ¹⁴C‐cholesterol and ³H‐sitostanol absorption assay. Similar to our earlier study on Mmp2^−/− mice, we observed that Mmp9^−/− mice had elevated plasma secreted phospholipase A₂ activity. Pharmacological inhibition of systemic circulating secreted phospholipase A₂ activity (with varespladib) partially normalized the hepatic transcriptional responses to dietary cholesterol in Mmp9^−/− mice. Functional studies with mice deficient in other MMPs suggested an important role for the MMP system, as a whole, in modulation of cholesterol metabolism.

Conclusions

Our results show that MMP‐9 modulates cholesterol metabolism, at least in part, through a novel MMP‐9–plasma secreted phospholipase A₂ axis that affects the hepatic transcriptional responses to dietary cholesterol. Furthermore, the data suggest that dysregulation of the MMP system can result in metabolic disorder, which could lead to atherosclerosis and coronary heart disease.

Increased MMP-7 expression in biliary epithelium and serum underpins native liver fibrosis after successful portoenterostomy in biliary atresia

The molecular mechanisms underlying progressive liver fibrosis following surgical treatment of biliary atresia (BA) remain unclear. Our aim was to address hepatic gene and protein expression and serum levels of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) after successful portoenterostomy (PE), and relate them to histological signs of liver injury, clinical follow‐up data and biochemical markers of hepatic function. LIver biopsies and serum samples were obtained from 25 children after successful PE at median age of 3.3 years. Serum MMP concentrations were determined by enzyme‐linked immune sorbent assay. Hepatic gene expression of MMPs and TIMPs was analyzed using real‐time reverse‐transcription PCR. Liver expression of MMP‐7 and cytokeratin‐7 was studied using immunohistochemistry. Despite effective clearance of biochemical and histological cholestasis following PE, BA patients showed increased hepatic gene expression of MMP‐7 (29‐fold, p < 0.001), MMP‐2 (3.1‐fold, p < 0.001), MMP‐14 (1.7‐fold, p = 0.007), and TIMP‐1 (1.8‐fold, p < 0.001), when compared to controls. Similar to a biliary epithelial marker cytokeratin‐7, expression of MMP‐7 localized in biliary epithelium of bile ducts and ductal proliferations and periportal hepatocytes and was increased (p < 0.001) in relation to controls. BA patients had 6‐fold higher serum levels of MMP‐7 (p < 0.001), which correlated positively with hepatic MMP‐7 gene (r = 0.548, p = 0.007) and protein (r = 0.532, p = 0.007) expression. Patients showed a positive correlation between biliary MMP‐7 expression and Metavir fibrosis stage (r = 0.605, p = 0.001) and portal fibrosis grade (r = 0.606, p = 0.001). Neither similarly increased MMP‐7 expression nor correlation with liver fibrosis was observed in patients with intestinal failure‐associated liver disease and comparable Metavir stage. In conclusion, our findings support an unique role of altered hepatic expression of MMP‐7 in the progression of liver fibrosis after successful PE and introduce a potential therapeutic target to pharmacologically extend native liver survival by inhibiting MMP‐7 hyperactivity. Serum MMP‐7 may be a valuable postoperative prognostic tool in BA.

Transcriptional profiling of chronic clinical hepatic schistosomiasis japonica indicates reduced metabolism and immune responses

Schistosomiasis is a significant cause of human morbidity and mortality. We performed a genome-wide transcriptional survey of liver biopsies obtained from Chinese patients with chronic schistosomiasis only, or chronic schistosomiasis with a current or past history of viral hepatitis B. Both disease groups were compared with patients with no prior history or indicators of any liver disease. Analysis showed in the main, downregulation in gene expression, particularly those involved in signal transduction via EIF2 signalling and mTOR signalling, as were genes associated with cellular remodelling. Focusing on immune associated pathways, genes were generally downregulated. However, a set of three genes associated with granulocytes, MMP7, CLDN7, CXCL6 were upregulated. Differential gene profiles unique to schistosomiasis included the gene Granulin which was decreased despite being generally considered a marker for liver disease, and IGBP2 which is associated with increased liver size, and was the most upregulated gene in schistosomiasis only patients, all of which presented with hepatomegaly. The unique features of gene expression, in conjunction with previous reports in the murine model of the cellular composition of granulomas, granuloma formation and recovery, provide an increased understanding of the molecular immunopathology and general physiological processes underlying hepatic schistosomiasis.

Matrix metalloproteinases in liver injury, repair and fibrosis

The liver is a large highly vascularized organ with a central function in metabolic homeostasis, detoxification, and immunity. Due to its roles, the liver is frequently exposed to various insults which can cause cell death and hepatic dysfunction. Alternatively, the liver has a remarkable ability to self-repair and regenerate after injury. Liver injury and regeneration have both been linked to complex extracellular matrix (ECM) related pathways. While normal degradation of ECM components is an important feature of tissue repair and remodeling, irregular ECM turnover contributes to a variety of liver diseases. Matrix metalloproteinases (MMPs) are the main enzymes implicated in ECM degradation. MMPs not only remodel the ECM, but also regulate immune responses. In this review, we highlight some of the MMP-attributed roles in acute and chronic liver injury and emphasize the need for further experimentation to better understand their functions during hepatic physiological conditions and disease progression.

Overexpression of MMP-7 Increases Collagen 1A2 in the Aging Kidney

The percentage of the U.S. population over 65 is rapidly increasing, as is the incidence of chronic kidney disease (CKD). The kidney is susceptible to age-dependent alterations in structure, specifically tubulointerstitial fibrosis that leads to CKD. Matrix metalloproteinases (MMPs) were initially characterized as extracellular matrix (ECM) proteinases; however, it is clear that their biological role is much larger. We have observed increased gene expression of several MMPs in the aging kidney, including MMP-7. MMP-7 overexpression was observed starting at 16 months, with over a 500-fold upregulation in 2-year-old animals. Overexpression of MMP-7 is not observed in age-matched, calorically restricted controls that do not develop fibrosis and renal dysfunction, suggesting a role in the pathogenesis. In order to delineate the contributions of MMP-7 to renal dysfunction, we overexpressed MMP-7 in NRK-52E cells. High-throughput sequencing of the cells revealed that two collagen genes, Col1a2 and Col3a1, were elevated in the MMP-7 overexpressing cells. These two collagen genes were also elevated in aging rat kidneys and temporally correlated with increased MMP-7 expression. Addition of exogenous MMP-7, or conditioned media from MMP-7 overexpressing cells also increased Col1A2 expression. Inhibition of protein kinase A (PKA), src, and MAPK signaling at p38 and ERK was able to attenuate the MMP-7 upregulation of Col1a2. Consistent with this finding, increased phosphorylation of PKA, src, and ERK was seen in MMP-7 overexpressing cells and upon exogenous MMP-7 treatment of NRK-52E cells. These data suggest a novel mechanism by which MMP-7 contributes to the development of fibrosis leading to CKD.

Expression of matrix metalloproteinases and their inhibitors in the woodchuck model of hepatocellular carcinoma

Matrix metalloproteinases (MMPs) play a central role in tumor invasion and metastasis. Increased expression of MMPs occurs during development of hepatocellular carcinoma (HCC) in humans following infection with hepatitis B virus (HBV). Woodchucks are used as an animal model for hepadnavirus-induced HCC. All woodchucks infected chronically with woodchuck hepatitis virus (WHV), a virus that is closely related to HBV, develop HCC. In the present study MMPs and related molecules were investigated in woodchucks to better understand the mechanisms of extracellular matrix remodeling in HCC. Three groups of samples were studied: liver and HCC tissues from animals infected with WHV and age- and gender-matched normal liver from animals not infected with WHV. New partial gene sequences for woodchuck MMP-2, MMP-7, and MMP-9 as well as their inhibitors NGAL, TIMP-1, and TIMP-2 were identified and used for determination of expression levels in liver and HCC by qRT-PCR. Compared to liver of WHV-naïve woodchucks, high levels of MMP-1, MMP-2, MMP-7, NGAL, and TIMP-1 were detected in liver of animals infected with WHV. However, no differences were found for TIMP-2. MMP-9 expression was higher in HCC than in liver of animals not infected with WHV. Immunohistochemical staining demonstrated that MMP-9 immunoreactivity was most intense in HCC, correlating with the progression of liver disease. Upregulation of MMP-9 in HCC was confirmed by Western blotting and zymography analysis. Furthermore, the activity of woodchuck MMPs was suppressed by BiPS, a common inhibitor of mammalian MMPs. These results suggest the use of MMP inhibitors as a potential HCC treatment strategy that could be explored in woodchucks.

Role of various proteases in cardiac remodeling and progression of heart failure

It is believed that cardiac remodeling due to geometric and structural changes is a major mechanism for the progression of heart failure in different pathologies including hypertension, hypertrophic cardiomyopathy, dilated cardiomyopathy, diabetic cardiomyopathy, and myocardial infarction. Increases in the activities of proteolytic enzymes such as matrix metalloproteinases, calpains, cathepsins, and caspases contribute to the process of cardiac remodeling. In addition to modifying the extracellular matrix, both matrix metalloproteinases and cathepsins have been shown to affect the activities of subcellular organelles in cardiomyocytes. The activation of calpains and caspases has been identified to induce subcellular remodeling in failing hearts. Proteolytic activities associated with different proteins including caspases, calpain, and the ubiquitin-proteasome system have been shown to be involved in cardiomyocyte apoptosis, which is an integral part of cardiac remodeling. This article discusses and compares how the activities of various proteases are involved in different cardiac abnormalities with respect to alterations in apoptotic pathways, cardiac remodeling, and cardiac dysfunction. An imbalance appears to occur between the activities of some proteases and their endogenous inhibitors in various types of hypertrophied and failing hearts, and this is likely to further accentuate subcellular remodeling and cardiac dysfunction. The importance of inhibiting the activities of both extracellular and intracellular proteases specific to distinct etiologies, in attenuating cardiac remodeling and apoptosis as well as biochemical changes of subcellular organelles, in heart failure has been emphasized. It is suggested that combination therapy to inhibit different proteases may prove useful for the treatment of heart failure.

Liver regeneration signature in hepatitis B virus (HBV)-associated acute liver failure identified by gene expression profiling

INTRODUCTION

The liver has inherent regenerative capacity via mitotic division of mature hepatocytes or, when the hepatic loss is massive or hepatocyte proliferation is impaired, through activation of hepatic stem/progenitor cells (HSPC). The dramatic clinical course of acute liver failure (ALF) has posed major limitations to investigating the molecular mechanisms of liver regeneration and the role of HSPC in this setting. We investigated the molecular mechanisms of liver regeneration in 4 patients who underwent liver transplantation for hepatitis B virus (HBV)-associated ALF.

METHODS AND FINDINGS

Gene expression profiling of 17 liver specimens from the 4 ALF cases and individual specimens from 10 liver donors documented a distinct gene signature for ALF. However, unsupervised multidimensional scaling and hierarchical clustering identified two clusters of ALF that segregated according to histopathological severity massive hepatic necrosis (MHN; 2 patients) and submassive hepatic necrosis (SHN; 2 patients). We found that ALF is characterized by a strong HSPC gene signature, along with ductular reaction, both of which are more prominent in MHN. Interestingly, no evidence of further lineage differentiation was seen in MHN, whereas in SHN we detected cells with hepatocyte-like morphology. Strikingly, ALF was associated with a strong tumorigenesis gene signature. MHN had the greatest upregulation of stem cell genes (EpCAM, CK19, CK7), whereas the most up-regulated genes in SHN were related to cellular growth and proliferation. The extent of liver necrosis correlated with an overriding fibrogenesis gene signature, reflecting the wound-healing process.

CONCLUSION

Our data provide evidence for a distinct gene signature in HBV-associated ALF whose intensity is directly correlated with the histopathological severity. HSPC activation and fibrogenesis positively correlated with the extent of liver necrosis. Moreover, we detected a tumorigenesis gene signature in ALF, emphasizing the close relationship between liver regeneration and liver cancer.

Liver regeneration signature in hepatitis B virus (HBV)-associated acute liver failure identified by gene expression profiling

Introduction

The liver has inherent regenerative capacity via mitotic division of mature hepatocytes or, when the hepatic loss is massive or hepatocyte proliferation is impaired, through activation of hepatic stem/progenitor cells (HSPC). The dramatic clinical course of acute liver failure (ALF) has posed major limitations to investigating the molecular mechanisms of liver regeneration and the role of HSPC in this setting. We investigated the molecular mechanisms of liver regeneration in 4 patients who underwent liver transplantation for hepatitis B virus (HBV)-associated ALF.

Methods and Findings

Gene expression profiling of 17 liver specimens from the 4 ALF cases and individual specimens from 10 liver donors documented a distinct gene signature for ALF. However, unsupervised multidimensional scaling and hierarchical clustering identified two clusters of ALF that segregated according to histopathological severity massive hepatic necrosis (MHN; 2 patients) and submassive hepatic necrosis (SHN; 2 patients). We found that ALF is characterized by a strong HSPC gene signature, along with ductular reaction, both of which are more prominent in MHN. Interestingly, no evidence of further lineage differentiation was seen in MHN, whereas in SHN we detected cells with hepatocyte-like morphology. Strikingly, ALF was associated with a strong tumorigenesis gene signature. MHN had the greatest upregulation of stem cell genes (EpCAM, CK19, CK7), whereas the most up-regulated genes in SHN were related to cellular growth and proliferation. The extent of liver necrosis correlated with an overriding fibrogenesis gene signature, reflecting the wound-healing process.

Conclusion

Our data provide evidence for a distinct gene signature in HBV-associated ALF whose intensity is directly correlated with the histopathological severity. HSPC activation and fibrogenesis positively correlated with the extent of liver necrosis. Moreover, we detected a tumorigenesis gene signature in ALF, emphasizing the close relationship between liver regeneration and liver cancer.

Syndecan-2 is a novel target of insulin-like growth factor binding protein-3 and is over-expressed in fibrosis

Extracellular matrix deposition and tissue scarring characterize the process of fibrosis. Transforming growth factor beta (TGFβ) and Insulin-like growth factor binding protein-3 (IGFBP-3) have been implicated in the pathogenesis of fibrosis in various tissues by inducing mesenchymal cell proliferation and extracellular matrix deposition. We identified Syndecan-2 (SDC2) as a gene induced by TGFβ in an IGFBP-3-dependent manner. TGFβ induction of SDC2 mRNA and protein required IGFBP-3. IGFBP-3 independently induced production of SDC2 in primary fibroblasts. Using an ex-vivo model of human skin in organ culture expressing IGFBP-3, we demonstrate that IGFBP-3 induces SDC2 ex vivo in human tissue. We also identified Mitogen-activated protein kinase-interacting kinase (Mknk2) as a gene induced by IGFBP-3. IGFBP-3 triggered Mknk2 phosphorylation resulting in its activation. Mknk2 independently induced SDC2 in human skin. Since IGFBP-3 is over-expressed in fibrotic tissues, we examined SDC2 levels in skin and lung tissues of patients with systemic sclerosis (SSc) and lung tissues of patients with idiopathic pulmonary fibrosis (IPF). SDC2 levels were increased in fibrotic dermal and lung tissues of patients with SSc and in lung tissues of patients with IPF. This is the first report describing elevated levels of SDC2 in fibrosis. Increased SDC2 expression is due, at least in part, to the activity of two pro-fibrotic factors, TGFβ and IGFBP-3.

Matrilysin (MMP-7) inhibition of BMP-7 induced renal tubular branching morphogenesis suggests a role in the pathogenesis of human renal dysplasia

Congenital renal dysplasia (RD) is a severe form of congenital renal malformation characterized by disruption of normal renal development with cyst formation, reduced or absent nephrons, and impaired renal growth. The authors previously identified that matrilysin (matrix metalloproteinase-7) was overexpressed in a microarray gene expression analysis of human RD compared to normal control kidneys. They now find that active matrilysin gene transcription and protein synthesis occur within dysplastic tubules and epithelial cells lining cysts in human RD by RT-PCR and immunohistochemistry. Similar staining patterns were seen in obstructed kidneys of pouch opossums that show histological features similar to that of human RD. In vitro, matrilysin inhibits formation of branching structures in mIMCD-3 cells stimulated by bone morphogenetic protein-7 (BMP-7) but does not inhibit hepatocyte growth factor-stimulated branching. BMP-7 signaling is essential for normal kidney development, and overexpression of catalytically active matrilysin in human embryonic kidney 293 cells reduces endogenous BMP-7 protein levels and inhibits phosphorylation of BMP-7 SMAD signaling intermediates. These findings suggest that matrilysin expression in RD may be an injury response that disrupts normal nephrogenesis by impairing BMP-7 signaling.

Matrix metalloproteinase-7 as a surrogate marker predicts renal Wnt/β-catenin activity in CKD

A variety of chronic kidney diseases exhibit reactivation of Wnt/β-catenin signaling. In some tissues, β-catenin transcriptionally regulates matrix metalloproteinase-7 (MMP-7), but the association between MMP-7 and Wnt/β-catenin signaling in chronic kidney disease is unknown. Here, in mouse models of both obstructive nephropathy and focal segmental glomerulosclerosis (adriamycin nephropathy), we observed upregulation of MMP-7 mRNA and protein in a time-dependent manner. The pattern and extent of MMP-7 induction were positively associated with Wnt/β-catenin signaling in these models. Activation of β-catenin through ectopic expression of Wnt1 promoted MMP-7 expression in vivo, whereas delivery of the gene encoding the endogenous Wnt antagonist Dickkopf-1 abolished its induction. Levels of MMP-7 protein detected in the urine correlated with renal Wnt/β-catenin activity. Pharmacologic blockade of Wnt/β-catenin signaling by paricalcitol inhibited MMP-7 expression in diseased kidneys and reduced the levels detected in the urine. In vitro, β-catenin activation induced the expression and secretion of MMP-7 and promoted the binding of T cell factor to the MMP-7 promoter in kidney epithelial cells. We also observed higher levels of MMP-7 expression, which correlated with β-catenin, in kidney tissue from patients with various nephropathies. In summary, levels of renal MMP-7 correlate with Wnt/β-catenin activity, and urinary MMP-7 may be a noninvasive biomarker of this profibrotic signaling in the kidney.

Serum MMP-7 is increased in diabetic renal disease and diabetic diastolic dysfunction

Circulating matrix metalloproteinase (MMP) levels may correlate with diabetic complications. Whether they are changed in early diabetic cardiomyopathy is not known and was examined in this study. TIMP-1 and collagen degradation products were also measured. Results from subjects with and without diastolic dysfunction were compared with those obtained for patients with varying stages of diabetic renal disease. Patients with type 2 diabetes with or without diastolic dysfunction with varying degrees of renal disease were recruited for this study. Age-matched non-diabetic subjects served as controls. MMPs (-1, -3 and -7) and TIMP-1 were measured by ELISA, MMP-2 and -9 by zymography and collagen degradation products by radioimmunoassay. Differences in the pattern of MMPs/TIMPs and collagen degradation products were observed. The most consistent change was in totalMMP-7, which was increased in those with diastolic dysfunction and those with macroalbuminuria. MMP-7 correlated with cardiac function (p<0.05 vs control, in those with diastolic dysfunction), and renal filtration function (p<0.05 vs control). In summary, we have identified novel relationships between serum MMP-7 and diabetic complications specifically in renal disease and in diastolic dysfunction. How increased circulating MMP-7 is associated with these diabetic microvascular complications and the significance of these findings will require prospective studies.

A novel nonsynonymous variant of matrix metalloproteinase-7 confers risk of liver cirrhosis

Liver cirrhosis is characterized by progressive accumulation of extracellular matrix following chronic liver injuries. In the extracellular space, the constant turnover of liver matrix is regulated by the matrix metalloproteinase (MMP) class of enzyme. To assess whether genetic variations in MMP would result in diversity of liver cirrhosis, a case-control study of 320 patients with hepatocellular carcinoma, with or without cirrhosis, was conducted. Ten single-nucleotide polymorphism markers from four potential fibrosis-associated genes were selected for genotyping. Among these genes, a nonsynonymous single-nucleotide polymorphism which generates the variation of Gly-137 and Asp-137 in the MMP-7 gene was found to be strongly associated with the development of liver cirrhosis. In contrast to MMP-7(Gly-137) that predominantly secretes out into the cell culture medium, the cirrhosis-associated MMP-7(Asp-137) variant is preferentially localized on the extracellular membranes where it exerts its proteolytic activity on pericellular substrates. Functional analysis demonstrated an increased ability of the MMP-7(Asp-137) variant to associate with the cell surface CD151 molecule. In wound-healing and Boyden chamber assays, cell motility was specifically enhanced with the expression of MMP-7(Asp-137) as compared to the cells expressing MMP-7(Gly-137). These results demonstrate that the MMP-7(Asp-137) variant confers a gain-of-function phenotype for MMP-7.

CONCLUSION

We have identified a novel genetic association of MMP-7(Asp-137) variant with liver cirrhosis in patients with hepatocellular carcinoma. Whether the MMP-7 variant can be a new marker for liver cirrhosis will be further studied.

Renal allografts with IF/TA display distinct expression profiles of metzincins and related genes

Chronic renal allograft injury is often reflected by interstitial fibrosis (IF) and tubular atrophy (TA) without evidence of specific etiology. In most instances, IF/TA remains an irreversible disorder, representing a major cause of long-term allograft loss. As members of the protease family metzincins and functionally related genes are involved in fibrotic and sclerotic processes of the extracellular matrix (ECM), we hypothesized their deregulation in IF/TA. Gene expression and protein level analyses using allograft biopsies with and without Banff'05 classified IF/TA illustrated their deregulation. Expression profiles of these genes differentiated IF/TA from Banff'05 classified Normal biopsies in three independent microarray studies and demonstrated histological progression of IF/TA I to III. Significant upregulation of matrix metalloprotease-7 (MMP-7) and thrombospondin-2 (THBS-2) in IF/TA biopsies and sera was revealed in two independent patient sets. Furthermore, elevated THBS-2, osteopontin (SPP1) and beta-catenin may play regulatory roles on MMP. Our findings further suggest that deregulated ECM remodeling and possibly epithelial to mesenchymal transition (EMT) are implicated in IF/TA of kidney transplants, and that metzincins and related genes play an important role in these processes. Profiling of these genes may be used to complement IF/TA diagnosis and to disclose IF/TA progression in kidney transplant recipients.

Immunological investigation of the hepatic tissue from infants with biliary atresia

PURPOSE

Matrix metalloproteinases (MMPs) and their endogenous tissue inhibitors [tissue inhibitors of metalloproteinases (TIMPs)] have been implicated in tissue injury and remodeling in many organs. The objective of this study was to evaluate the expression of MMP-3 and -9, and TIMP-1, -2, and -3 and their relationship to liver fibrosis in infants with biliary atresia.

METHODS

The expression of MMP-3 and-9 and TIMP-1, -2 and -3 was investigated in liver tissue samples of nine patients with biliary atresia. In addition, the expression of CCR-4 and CCR-5 was analyzed to investigate the activation of Th1 and Th2 cells. The mRNA levels were measured by semiquantitative reverse transcriptase polymerase chain reaction.

RESULTS

The expression of MMP-3 was higher than that of MMP-9 in all samples (P < 0.01). The expression of TIMP-1 was higher than that of TIMP-2 and -3 in all samples (P < 0.01). The expression of CCR-5 was higher than that of CCR-4 (P < 0.05), which implied higher activation of Th1 cells relative to Th2 cells.

CONCLUSION

Our findings suggest that MMP-3, possibly induced by Th1 cytokines, and its balance with TIMP-1, may be one of the factors involved in the pathogenesis of biliary atresia.

Matrix metalloproteinase 7 is required for tumor formation, but dispensable for invasion and fibrosis in SMAD4-deficient intestinal adenocarcinomas

Expression of matrix metalloproteinase 7 (MMP7) is increased in the human colorectal carcinomas, and correlates with malignant progression. However, its contribution to colon cancer pathogenesis is not understood thoroughly. To investigate the roles of MMP7 in colon cancer progression, we introduced an Mmp7 knockout mutation into the cis-Apc/Smad4 mutant mouse, a model of invasive colon cancer in which SMAD4-dependent TGF-beta family signaling is inactivated. We demonstrate here that lack of MMP7 reduces the number and size of tumors in the cis-Apc/Smad4 mice. On the other hand, MMP7-deficiency does not affect the depth of tumor invasion, number of stromal fibroblasts or levels of extracellular matrix components in the tumors. These results indicate that MMP7 is required for tumor formation, but not for the invasion or fibrosis of the colon cancer whose SMAD4-dependent TGF-beta family signaling is blocked.

Role of Kupffer cells in hepatic fibrosis

Kupffer cells (KC), a kind of nonparenchymal cells and defenders in the liver, release various chemical mediators to induce liver injury, and play an important role in many pathologic changes of the liver. Hepatic fibrosis is the common pathologic process of varied chronic liver diseases, and it is also a "transfer station" for many chronic liver diseases lapsing to cirrhosis. As important influencing factors, cytokines secreted by KC are involved in the occurrence and progression of hepatic fibrosis. Therefore, lucubrating the role and mechanism of KC in the progression of hepatic fibrosis, and investigating the KC-related therapeutic strategies of anti-fibrosis have practical significances for the prevention and treatment of liver injury and the raise of patients' survival rates in clinical practice.

Changes in expression of extracellular matrix genes, fibrogenic factors, and actin cytoskeletal organization in retinol treated and untreated vocal fold stellate cells

The regulation of extracellular matrix (ECM) constituency is critical in maintaining vocal cord biomechanical viscoelasticity required for phonation. Recently our laboratory successfully isolated and cultured a novel cell called a vocal fold stellate cell (VFSC), thought to play a central role in laryngeal ECM metabolism, aging, scarring and cancer. Our laboratory has shown that these cells undergo transdifferentiation that is partially reversed by exposure to all-trans retinol (ATROH). Here we make the first report on the expression of various ECM components, MMPs, TIMPs, pro-fibrogenic cytokines, and other ECM modulators in transdifferentiated and deactivated VFSCs. We show that VFSCs maintain an ECM expression pattern similar to laryngeal cancer and scars but distinct from tracheal fibroblasts. Exposure to ATROH differentially affects the VFSC expression of ECM components, matrix-regulating enzymes, and fibrogenic factors suggesting that the inhibitory effects of this synthetic cofactor should be studied further in laryngeal fibrosis and scarring. We also show that increased exposure to retinol induces sequential reorganization of the actin cytoskeleton in activated VFSCs. Our findings demonstrate that VFSCs are capable of regulating vocal fold ECM constituency important throughout normal laryngeal development. Furthermore, our results implicate VFSC activation in ECM misregulation which is a hallmark of several laryngeal pathologies.