Physiological and pathological analysis of BMP-3b in cardiovascular system.

BMP-3b最初从股骨中分离，在成骨细胞和发育中的胚胎中对BMP-2具有拮抗活性。虽然BMP-3b基因在主动脉中高表达，但其在心血管系统中的功能尚不清楚。关于BMP在该系统中的作用，自2000年报道BMP受体突变导致PPH的论文发表以来，一直处于活跃状态并不断取得进展。为了阐明BMP-3b在心血管系统中的作用，我们首先在培养的主动脉平滑肌细胞中检测了BMP-3b的作用。BMP-3b基因在大鼠和人细胞中均表达，其水平因制备方法（酶法和外植体法）而改变。用腺病毒过表达系统检测其生物学活性。结果显示BMP-3b具有生长抑制作用。在这些细胞中BMP-3b的内在形式的克隆过程中，我们分离出了从未知道的新的剪接变体。在这种新的变体中，BMP-3b活性的蛋白质的基本部分被删除，这表明将存在新的活性和BMP-3b的分子形式。接下来，我们研究了BMP-Sb在心脏中的功能。在培养的新生大鼠心肌细胞中，BMP-3b基因在心肌细胞和非心肌细胞中均有表达。在心脏的发育阶段（胚胎d8.5至d10.5），BMP-3b基因表达贯穿整个阶段，并且水平随阶段增加。另外，我们刚刚建立了BMP-3b在TG小鼠中的高表达，特别是在心脏中，BMP-3b在心脏中的表达水平比野生型高10到100倍。现在我们正在繁殖和检查这些老鼠。我们开发了BMP-3b的特异性抗体，并研究了BMP-3b的分子形式。我们发现分泌型BMP-3b的分子形式是BMP家族中从未报道过的，因此我们现在正在检查BMP-3b高表达的大鼠组织中的分子形式。

BMP-3b was originally isolated from femur and have antagonistic activity against BMP-2 in osteoblast and developing embryos. Although BMP-3b gene was highly expressed in aorta, its function in cardiovascular system is still unknown. Regarding the BMPs function in that system, it has been now active and being progress since the paper which reported that mutation of BMP receptor caused PPH was published in 2000. To clarify the function of BMP-3b in cardiovascular system, we first examined the effect of that in cultured aortic smooth muscle cells. BMP-3b gene was expressed in both in rat and human cells and level of that was changed by the preparation method(enzyme and explant method) . The biological activity was examined by adenovirus over-expression system. The result showed that BMP-3b had growth inhibitory effect. During cloning of the intrinsic form of BMP-3b in these cells, we isolated new splicing variant that was never known. In this new variant, essential part of BMP-3b activity of the protein was deleted, suggesting that there would be novel activity and molecular form of BMP-3b. Next, we examined the function of BMP-Sb in the heart. In the cultured cells from neonatal rat, BMP-3b gene was expressed both in myocyte and non-myocyte cells. In the developing stage of the heart(embryo d8.5 to d10.5), BMP-3b gene expression was observed through the entire stage and the level increased with stage. In addition, we have just generated TG mice overexpressing BMP-3b especially in heart, BMP-3b expression level was 10 to 100 times higher than wild ones in heart. Now we are breeding and examining these mice. We developed antibody specific for BMP-3b and investigated the molecular form of BMP-3b. We found that the molecular form of secreted BMP-3b was unique that was never reported in BMP family, so we are now checking the molecular form in rat tissues where BMP-3b was highly expressed.