Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.28 (chloramphenicol acetyltransferase)
 5,100 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hepatic stellate cells (HSC) differ in their phenotype depending on the initiation and progression of their activation. Our hypothesis was that different mechanisms govern type I collagen synthesis depending on stage of HSC activation. We investigated the role of alpha(5)beta(1)-integrin as a regulator of type I collagen gene COL1A1 expression in primary and passaged HSC cultures using transgenic mouse containing type I collagen gene COL1A1 promoter linked to the chloramphenicol acetyltransferase (CAT) reporter gene. The alpha(5)beta(1) protein levels increased during the activation and were highest in day 6 primary cultures but decreased in passaged HSC. CAT activity, reflecting COL1A1 expression, was upregulated by alpha(5)beta(1)-integrin. Inhibition of alpha(5)beta(1)-integrin by echistatin and blocking antibody resulted in reduced transgene activity only in early primary cultures (compared with the control, 53.3 +/- 12% echistatin and 58.8 +/- 7% blocking antibody, respectively, P < 0.05). Treatment of passaged HSC with either echistatin or blocking antibody had no effect. Fibronectin, an alpha(5)beta(1)-integrin ligand, increased transgene activity in primary (210 +/- 33%, P < 0.05) but not in passaged HSC cultures (119 +/- 8%). This alpha(5)beta(1)-integrin effect appears to be at least in part mediated by CCAAT enhancer binding protein-beta (C/EBPbeta), because fibronectin increased and alpha(5)-gene silencing by small interfering RNA decreased C/EBPbeta levels. In addition, C/EBPbeta knockout mice showed reduced type I collagen synthesis compared with wild-type littermates. Therefore alpha(5)beta(1)-integrin is an important regulator of type I collagen production in early primary HSC cultures but appears to have no direct role once the HSC are fully activated.
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PMID:Differences in regulation of type I collagen synthesis in primary and passaged hepatic stellate cell cultures: the role of alpha5beta1-integrin. 1751 Jan 95

Platelet-rich plasma (PRP) is derived from fresh whole blood, which contains a high concentration of platelets. Recently, PRP has been used for skin wound healing and rejuvenation. However, the molecular mechanisms underlying PRP-inducing wound healing processes are still largely unknown. The aim of this study is to evaluate the effect of PRP on the expression of G1 cell cycle regulatory proteins, type I collagen, matrix metalloproteinase-1 (MMP-1), and MMP-2 in human skin fibroblasts (HSF). We performed a cell proliferation and a migration assay, immunoblotting, and a chloramphenicol acetyltransferase (CAT) assay in PRP-treated human skin fibroblasts. PRP treatment induced increased rates of cell proliferation and cell migration. Expression of cyclin A protein was increased by a low concentration (0.5%) of PRP-treated HSF. In addition, expression of Rb, cyclin E, and cyclin-dependent kinase 4 proteins was increased by a high concentration (5%) of PRP-treated HSF. High concentration of PRP induced an up-regulation of type I collagen, MMP-1, and MMP-2 expression in HSF. Taken together, PRP treatment induced an increase in expression of G1 cell cycle regulators, type I collagen and MMP-1, thereby accelerating the wound healing process.
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PMID:Platelet-rich plasma induces increased expression of G1 cell cycle regulators, type I collagen, and matrix metalloproteinase-1 in human skin fibroblasts. 2196 87


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