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Plasmin plays a key role in the regulation of profibrogenic molecules in hepatic stellate cells
Author(s) -
MartínezRizo Abril,
BuenoTopete Miriam,
GonzálezCuevas Jaime,
ArmendárizBorunda Juan
Publication year - 2010
Publication title -
liver international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.873
H-Index - 110
eISSN - 1478-3231
pISSN - 1478-3223
DOI - 10.1111/j.1478-3231.2009.02155.x
Subject(s) - plasmin , plasminogen activator , hepatic stellate cell , microbiology and biotechnology , activator (genetics) , urokinase , matrix metalloproteinase , chemistry , biology , transforming growth factor beta , signal transduction , endocrinology , biochemistry , gene , enzyme , genetics
Background: Plasmin role in transforming growth factor‐β (TGF‐β)‐responsive gene regulation remains to be elucidated. Also, plasmin action on co‐repressor Ski‐related novel protein N (SnoN) and differential activation of matrix metalloproteinases (MMPs) are unknown. Thus, the role of plasmin on profibrogenic molecule expression, SnoN transcriptional kinetics and gelatinase activation was investigated. Methods: Hepatic stellate cells (HSC) were transduced with adenovirus‐mediated human urokinase plasminogen activator (Ad‐huPA) (4 × 10 9 viral particles/ml). Overexpression of urokinase plasminogen activator and therefore of plasmin, was blocked by tranexamic acid (TA) in transduced HSC. Gene expression was monitored by reverse transcriptase polymerase chain reaction. HSC‐free supernatants were used to evaluate MMP‐2 and MMP‐9 by zymography. SnoN, TGF‐β and tissue inhibitor of metalloproteinase (TIMP)‐1 were analysed by Western blot. Plasmin and SnoN expression kinetics were evaluated in bile duct‐ligated (BDL) rats. Results: Plasmin overexpression in Ad‐huPA‐transduced HSC significantly decreased gene expression of profibrogenic molecules [α 1 (I)collagen 66%, TIMP‐1 59%, α‐smooth muscle actin 90% and TGF‐β 55%]. Interestingly, both SnoN gene and protein expression increased prominently. Plasmin inhibition by TA upregulated the profibrogenic genes, which respond to TGF‐β‐intracellular signalling. In contrast, SnoN mRNA and protein dropped importantly. Plasmin‐activated MMP‐9 and MMP‐2 in HSC supernatants. Taken together, these findings indicate that MMP‐9 activation is totally plasmin dependent. SnoN levels significantly decreased in cholestatic‐BDL rats (82%) as compared with control animals. Interestingly, hepatic plasmin levels dropped 46% in BDL rats as compared with control. Conclusion: Plasmin plays a key role in regulating TGF‐β‐responding genes. In particular, regulation of TGF‐β‐co‐repressor (SnoN) is greatly affected, which suggests SnoN as a cardinal player in cholestasis‐induced fibrogenesis.