Regulation of TGFβ1-mediated collagen formation by LOX-1 -: Studies based on forced overexpression of TGFβ1 in wild-type and LOX-1 knock-out mouse cardiac fibroblasts
Regulation of TGFβ1-mediated collagen formation by LOX-1 -: Studies based on forced overexpression of TGFβ1 in wild-type and LOX-1 knock-out mouse cardiac fibroblasts
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DOI：
10.1074/jbc.m708820200
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发表时间：
2008-04-18
影响因子：
4.8
通讯作者：
Mehta, Jawahar L.
中科院分区：
文献类型：
--
作者：
Hu, Changping;Dandapat, Abhijit;Mehta, Jawahar L.
转化生长因子β（1）（TGF β（1））激活导致组织纤维化。在此，我们报道了LOX-1（一种氧化低密度脂蛋白的凝集素样52-kDa受体）在小鼠心脏成纤维细胞TGF β 1介导的胶原表达和潜在信号传导中的作用。通过用携带活性TGF β（1）部分的腺相关病毒2型载体（AAV/TGF β（ACT）（1））转染，TGF β（1）在野生型（WT）和LOX-1敲除小鼠心脏成纤维细胞中过表达。用AAV/TGF β（ACT）（1）转染WT小鼠心脏成纤维细胞显著增强了NADPH氧化酶（p22（phox）、p47（phox）和gp 91（phox）亚基）和LOX-1的表达、活性氧的形成和胶原蛋白合成，同时增加了p38和p44/42丝裂原活化蛋白激酶（MAPK）的活化。在LOX-1基因敲除小鼠心脏成纤维细胞以及用特异性抗LOX-1抗体处理的WT小鼠心脏成纤维细胞中，TGF β 1介导的胶原合成增加显著减弱。用抗LOX-1抗体处理也降低NADPH氧化酶表达和MAPK活化。NADPH氧化酶抑制剂和gp 91 phox小干扰RNA减少LOX-1的表达，MAPK激活，和胶原蛋白的形成。p38 MAPK抑制剂以及p44/42 MAPK抑制剂减少了心脏成纤维细胞中胶原蛋白的形成，而不影响LOX-1的表达。这些观察结果表明，心脏成纤维细胞中的胶原合成涉及TGF β（1）-NADPH氧化酶和LOX-1之间的促进性相互作用。此外，MAPK途径的激活似乎是TGF β（1）-活性氧-LOX-1级联的下游。
Transforming growth factor beta(1) (TGF beta(1)) activation leads to tissue fibrosis. Here, we report on the role of LOX-1, a lectin-like 52-kDa receptor for oxidized low density lipoprotein, inTGF beta(1)-mediated collagen expression and underlying signaling in mouse cardiac fibroblasts. TGF beta(1) was overexpressed in wildtype (WT) and LOX-1 knock-out mouse cardiac fibroblasts by transfection with adeno-associated virus type 2 vector carrying the active TGF beta(1) moiety (AAV/TGF beta(ACT)(1)). Transfection of WT mouse cardiac fibroblasts with AAV/TGF beta(ACT)(1) markedly enhanced the expression of NADPH oxidases (p22(phox), p47(phox), and gp91(phox) subunits) and LOX-1, formation of reactive oxygen species, and collagen synthesis, concomitant with an increase in the activation of p38 and p44/42 mitogen-activated protein kinases (MAPK). The TGF beta(1)-mediated increase in collagen synthesis was markedly attenuated in the LOX-1 knock-out mouse cardiac fibroblasts as well as in WT mouse cardiac fibroblasts treated with a specific anti-LOX-1 antibody. Treatment with anti-LOX-1 antibody also reduced NADPH oxidase expression and MAPK activation. The NADPH oxidase inhibitors and gp91phox small interfering RNA reduced LOX-1 expression, MAPK activation, and collagen formation. The p38 MAPK inhibitors as well as the p44/42 MAPK inhibitors reduced collagen formation without affecting LOX-1 expression in cardiac fibroblasts. These observations suggest that collagen synthesis in cardiac fibroblasts involves a facilitative interaction between TGF beta(1)-NADPH oxidase and LOX-1. Further, the activation of MAPK pathway appears to be downstream of TGF beta(1)-reactive oxygen species-LOX-1 cascade.