Adrenomedullin inhibits proliferation of rat adventitia induced by lysophosphatidic acid / 中国病理生理杂志

ABSTRACT

] AIM: Lysophosphatidic acid (LPA) is a bioactive phospholipid known to have growth factor-like activity on fibroblasts, and is involved in cardiovascular diseases. Besides direct effects, usually, LPA can work together with other bioactive factors to regulate cardiovascular homeostasis by induction of their expression and production, or increase in their activity. Among variety of bioactive factors, adrenomedullin (ADM) is a multifunctional peptide with an important cytoprotective effect against cardiovascular damage, but the interaction between ADM and LPA on adventitia remains unknown. METHODS: The experiment was performed on the bath of isolated rat aortic adventitia, ADM produced and secreted from adventitia stimulated by LPA was detected by using radioimmunoassay, proliferation in adventitia cells was evaluated by the level of [3H]-thymine incorporation, and prepro ADM gene expression was measured by semi-quantitative reverse transcriptase polymerase chain reaction. RESULTS: It was found that LPA stimulated aortic adventitia to secrete ADM and express its mRNA in a concentration-dependent manner. ADM inhibited LPA-induced proliferation in adventitial cells, and attenuated the activity of mitogen activated protein kinase (MAPK) stimulated by LPA. In contrast, the treatment with specific antagonists of ADM receptor potentiated the LPA-induced proliferation in adventitial cells. CONCLUSION: LPA stimulates adventitia to produce and secrete ADM, and in turn, ADM produced by adventitia regulates the vascular biological effects of LPA. [