Tissue inhibitor of metalloproteinase-1 messenger RNA expression is enhanced relative to interstitial collagenase messenger RNA in experimental liver injury and fibrosis

✍ Scribed by J P Iredale; R C Benyon; M J Arthur; W F Ferris; R Alcolado; P J Winwood; N Clark; G Murphy

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 607 KB
• Volume: 24
• Category: Article
• ISSN: 0270-9139
• DOI: 10.1002/hep.510240129

✦ Synopsis

In liver fibrosis and cirrhosis there is a change in both the Liver fibrosis results from a relative imbalance beamount and relative composition of the hepatic extracellular tween synthesis and degradation of matrix proteins. We matrix. 1 Current evidence suggests that hepatic stellate cells have previously described release of the potent collagen-(lipocytes, fat-storing or Ito cells) are central to this process ase inhibitor, tissue inhibitor of metalloproteinase-1 both as the major source of fibrillar and nonfibrillar matrix (TIMP-1), by culture-activated human hepatic stellate proteins and matrix degrading metalloproteinases. 1-11 cells (HSCs). In this study, we have investigated the rela-

We have previously shown that cultured hepatic stellate tive expression of TIMP-1 and interstitial collagenase in cells (HSCs) activated to a myofibroblastic phenotype express culture-activated rat HSCs and rat models of liver injury gelatinase A (72-kd type IV collagenase/gelatinase) 12,13 and and fibrosis. The complementary DNA (cDNA) for rat there is evidence to suggest that they also secrete stromely-TIMP-1 was obtained by homology polymerase chain reaction (PCR) and sequenced. By Northern analysis using sin. 14 A further metalloproteinase, interstitial collagenase, this probe, TIMP-1 messenger RNA (mRNA) expression expressed by mesenchymal and other cell types has degradawas up-regulated with HSC activation by culture on tive activity against native collagen types I and III, 15,16 explastic as defined by cellular expression of procollagenpression of which could potentially initiate remodelling of 1. Interstitial collagenase mRNA was expressed in early fibrotic liver. culture (õ4 days) but became undetectable in more acti-Interstitial collagenase expression in liver has been varivated cells (7-21 days). By activity assay of serum-free ously ascribed to parenchymal and sinusoidal liver cells, incell-conditioned media, TIMP-1 was found to be released cluding Kupffer cells 17,18 and hepatocytes. 19,20 There is also in increasing concentrations with duration of culture on some evidence to indicate that HSCs are a cellular source of plastic. Expression of TIMP-1, interstitial collagenase, interstitial collagenase in liver; studies on a passaged celland procollagen-1 mRNAs were studied in rat models of line derived by outgrowth from human liver (of possible HSC biliary and parenchymal injury (bile duct ligation and origin) showed that interstitial collagenase is expressed con-CCl 4 administration) by ribonuclease protection assay. stitutively and is up-regulated in response to interleukin-TIMP-1 mRNA expression was increased at 6, 24 hours, 1 and tumor necrosis factor a. 21 Li et al. have also shown and 3 days after bile duct ligation and was also shown collagenase activity in cultured rat HSCs which was into rise in acute CCl 4 liver injury and remain elevated as creased in response to polyunsaturated lecithin. 22 the liver became fibrotic. TIMP-1 expression preceded

In studies undertaken to measure interstitial collagenase procollagen-1 expression in both models. In contrast, inactivity in liver fibrosis, a general pattern emerges; initially terstitial collagenase mRNA levels remained similar to there is a reversible phase with active matrix remodelling control values throughout both models of liver injury. and detectable collagenase activity. In late disease, fibrosis Total cellular RNA from hepatocytes, HSCs, and Kupffer becomes irreversible, and, at this point, collagenase activity cells freshly isolated from livers after acute CCl 4 injury falls. This pattern is observed in CCl 4 liver injury [23][24][25][26][27] and in was subjected to Northern analysis. TIMP-1 transcripts alcoholic liver disease of humans and baboons. 28,29 It is not were observed in nonparenchymal cells only. We suggest known whether this occurs as a result of altered interstitial that increased expression of TIMP-1 relative to intersticollagenase gene expression and biosynthesis, reduced protial collagenase by HSCs may promote progression of teolytic activation of latent procollagenase or through inhibiliver fibrosis in these rat models by preventing degradation of activated collagenase in the extracellular space by the tion of secreted collagens. (HEPATOLOGY 1996;24:176-184.) specific tissue inhibitors of metalloproteinases (TIMP-1) and TIMP-2.

We have previously described messenger RNA (mRNA) expression for the matrix metalloproteinase inhibitor, TIMP-1 Abbreviations: HSC, hepatic stellate cell; TIMP, tissue inhibitor of metalloproteinase; by culture-activated human HSCs. 30 We also established that mRNA, messenger RNA; cDNA, complementary DNA; SDS, sodium dodecyl sulfate.