Shalitin Noa, Schlesinger Hadassa, Levy Maurice J, Kessler Efrat, Kessler-Icekson Gania
Basil and Gerald Felsenstein Medical Research Center, Rabin Medical Center, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
J Cell Biochem. 2003 Oct 1;90(2):397-407. doi: 10.1002/jcb.10646.
Procollagen processing by procollagen C-proteinase (PCP) is an important step in collagen deposition. This reaction is stimulated by another glycoprotein, known as PCP enhancer. The objective of this study was to identify factors that regulate the expression of PCP enhancer in cardiac fibroblasts and examine possible correlation with collagen expression. Rat heart fibroblasts were cultured in the presence or absence of three known stimulators of collagen synthesis: ascorbic acid, TGF-beta, and aldosterone. The mRNA and protein levels of PCP enhancer and collagen type I were each assessed using Northern and Western blotting, respectively. Expression of PCP was assessed by RT-PCR and its activity in the culture media was determined using radioactive procollagen as the substrate. The levels of PCP enhancer mRNA increased 1.5- to 2-fold in response to ascorbate, TGF-beta, or aldosterone. This increase was paralleled by an up to fourfold increase in the level of the pro alpha1(I) collagen chain transcript and was accompanied by a marked increase in the levels of the respective proteins in the culture media. PCP activity in the culture media was also increased, apparently, without effect on its expression. These results indicate that expression of PCP enhancer in cultured rat heart fibroblasts is coordinated with that of collagen. The observed augmentation of PCP activity may be a consequence of the increase in the levels of PCP enhancer in the culture media.
前胶原C蛋白酶（PCP）对前胶原的加工是胶原沉积过程中的一个重要步骤。该反应受到另一种糖蛋白（称为PCP增强剂）的刺激。本研究的目的是确定调节心脏成纤维细胞中PCP增强剂表达的因素，并检查其与胶原表达的可能相关性。在存在或不存在三种已知的胶原合成刺激剂（抗坏血酸、转化生长因子-β和醛固酮）的情况下培养大鼠心脏成纤维细胞。分别使用Northern印迹法和Western印迹法评估PCP增强剂和I型胶原的mRNA和蛋白质水平。通过RT-PCR评估PCP的表达，并使用放射性前胶原作为底物测定其在培养基中的活性。抗坏血酸、转化生长因子-β或醛固酮使PCP增强剂mRNA水平增加1.5至2倍。这种增加伴随着前α1（I）胶原链转录水平高达四倍的增加，并伴随着培养基中相应蛋白质水平的显著增加。培养基中的PCP活性也增加，显然，这对其表达没有影响。这些结果表明，培养的大鼠心脏成纤维细胞中PCP增强剂的表达与胶原的表达是协调的。观察到的PCP活性增强可能是培养基中PCP增强剂水平增加的结果。
