XXXX pancreatic stellate cells secrete matrix metalloproteinases: implications for extracellular matrix turnover.

@entity6930 @entity12480 @entity5 @entity568 @entity991 @entity660 @entity1505 @entity11018 @entity2975 @entity6929 @entity1810 @entity35 @entity11017 @entity1068 @entity1577 @entity3094
BACKGROUND: @entity1577 is a characteristic feature of chronic @entity660 and is thought to result from a change in the balance between synthesis and degradation of extracellular matrix (ECM) proteins. Recent studies suggest that activated pancreatic stellate cells (PSCs) play a central role in pancreatic fibrogenesis via increased synthesis of ECM proteins. However, the role of these cells in ECM protein degradation has not been fully elucidated. AIMS: To determine: (i) whether PSCs secrete matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) and, if so (ii) whether MMP and @entity6930 secretion by PSCs is altered in response to known @entity991 activating factors such as @entity5 factor alpha ( @entity1505 ), @entity1810 ( @entity1810 ), @entity568 ( @entity568 ), @entity1068 , and @entity3094 . METHODS: Cultured @entity35 PSCs (n=3-5 separate cell preparations) were incubated at 37 degrees C for 24 hours with serum free culture medium containing @entity1505 (5-25 U/ml), @entity1810 (0.5-1 ng/ml), @entity568 (0.001-10 ng/ml), @entity1068 (10-50 mM), or @entity3094 (150-200 micro M), or no additions (controls). Medium from control cells was examined for the presence of MMPs by zymography using a 10% @entity2975 -0.1% gelatin gel. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to examine gene expression of @entity6929 and the tissue inhibitors of metalloproteinases @entity6930 and @entity11018 . Western blotting was used to identify a specific MMP, @entity11017 (a gelatinase that digests basement membrane collagen and the dominant MMP observed on zymography) and a specific @entity6930 , @entity11018 . Reverse zymography was used to examine functional TIMPs in @entity991 secretions. The effect of @entity1505 , @entity1810 , and @entity568 on @entity11017 secretion was assessed by densitometry of western blots. The effect of @entity1068 and @entity3094 on @entity11017 and @entity11018 secretion was also assessed by this method. RESULTS: Zymography revealed that PSCs secrete a number of MMPs including proteinases with molecular weights consistent with @entity11017 , @entity6929 , and @entity12480 . RT-PCR demonstrated the presence of mRNA for metalloproteinase inhibitors @entity6930 and @entity11018 in PSCs while reverse zymography revealed the presence of functional @entity11018 in @entity991 secretions. @entity11017 secretion by PSCs was significantly increased by @entity1810 and @entity568 , but was not affected by @entity1505 . @entity1068 and @entity3094 induced secretion of both @entity11017 and @entity11018 by PSCs. CONCLUSIONS: Pancreatic stellate cells have the capacity to synthesise a number of matrix metalloproteinases, including @entity11017 , @entity6929 , and @entity12480 and their inhibitors @entity6930 and @entity11018 . @entity11017 secretion by PSCs is significantly increased on exposure to the proinflammatory cytokines @entity1810 and @entity568 . Both @entity1068 and its metabolite @entity3094 increase @entity11017 as well as @entity11018 secretion by PSCs. IMPLICATION: The role of pancreatic stellate cells in extracellular matrix formation and fibrogenesis may be related to their capacity to regulate the degradation as well as the synthesis of extracellular matrix proteins.
