Function of hypertrophic growth in cardiocytes to furin belong to the yeast Kex2 endoprotease family

当心肌细胞受到拉伸力时，它们通过细胞肥大生长和升高的furin来适应。用furin特异性抑制剂孵育的细胞可抑制拉伸诱导的肥厚生长。因此，我们认为furin催化促生长前蛋白向活性形式的转化，这可能会诱导心肌细胞的肥厚生长。然后，我们检测了促生长肽转化生长因子-β(TGF-β)和甲状旁腺激素相关蛋白（PTHrP），包括furin特异性Arg-X-X-Arg （RXXR）基序。本研究采用分化良好的小鼠β细胞系MIN6，检测PTHrP的功能。早期传代的胰岛素含量较高，而晚期传代的胰岛素含量较低。Furin mRNA在传代后期的表达高于传代早期。葡萄糖刺激的胰岛素分泌水平在传代早期升高，但在传代后期下降。我们认为PTHrP的作用是在β细胞分化良好的情况下进一步分化，在正在生长的β细胞中进一步生长。我们认为PTHrP不会在单个β-细胞中同时诱导生长和分化。PTHrP与furin在拉伸心肌中共表达，因此，furin可能负责PTHrP蛋白向活性形式的转化。我们认为，PTHrP活性形式指示肥厚心肌进一步生长和正常心肌进一步收缩力。我们检测了PTHrP是否在心肌中表现出肥厚性生长和收缩力。通过结扎大鼠左冠状动脉前降支产生实验性心肌梗死（MI）。采用Northern blot检测心肌梗死后第1、3、7、14、28天心房和心室TGF-β、PTHrP和furin的表达。采用Western blot和免疫染色法检测心肌组织（包括梗死组织）中TGF-β、PTHrP和furin的免疫表达。当新生大鼠心肌通过拉伸诱导肥厚生长时，心肌表达高水平的蛋白加工酶furin。我们认为，furin特异性抑制剂deco - arg - val - lys - arg - cmk和具有抑制决定因子Arg-X-X-Arg的变体a1-抗胰蛋白酶抑制了拉伸诱导的心肌细胞肥厚生长。虽然我们调查了这些问题，但没有得到充分的结果。目前，考试将持续进行。少

When cardiocytes undergo the stretch force, they adapt by developing cellular hypertrophic growth and elevated furin. The cells incubated with furin-specific inhibitors were supressed the stretch-induced hypertrophoc growth. Thus, we suggest that furin catalyses the conversion of growth-promoting pro-proteins to their active form, which might induce hypertrophic growth in cardiocytes. Then, we examined growth-promoting peptied transforming growth factor -β(TGF-β) and parathyroid hormone-related protein (PTHrP) including the furin-specific Arg-X-X-Arg (RXXR) motif in myocardium. For study, we used of well-differentiated mouse β-cell line MIN6, and examined function of PTHrP.Early passage contained the high level of insulin, in contrust late passage content the low level of insulin.Furin mRNA were more expressed in late passage than in early passage. Glucosestimulated insulin secretion levels were increased in early passage, but were decresed in late passage. We suggest that the function … More of PTHrP induced further differentiation in well differentiated β-cell, and farther growth in growing β-cell.We believe that PTHrP does not indused growth and differentiation simultaneously in a single β-Cell. PTHrP is co-expressed with furin in stretched myocardium, therefor, furin may be responsible for the conversion of PTHrP proprotain to their active form. We believe that PTHrP active form indeces further growth in hypertrophic myocardium and further contractile force in normal myocardium. We examined whether PTHrP exhibits hypertrpphic growth and contractile force in myocardium. We generated exprimental myocardial infarction (MI) by ligating the left anterior discending coronary artery in rat. We examined TGF-β, PTHrP and furin expression in atrium and ventricles (on day 1 , 3, 7, 14, 28 after MI) by Northern blot. We exmined for immunodetection of TGF-β, PTHrP and furin by Western blot and immunostaining in the ventricular myocardium, including infarction tissue. When hypertrophic growth is induced in neonatal rat cardiocytes by stretching, the cardiocytes express high levels of the proprotein-processing enzyme furin. We believed that the furin-specific inhibitors, dec-Arg-Val-Lys-Arg-CMK and variant a1-antitrypsin with the inhibitory determinant Arg-X-X-Arg, suppressed the stretch-induced hypertrophic growth of cardiocytes.Though we examined these probrems, there were not rising on the suffcient results. At present, the examination will be continuously carried out. Less