Multi-center research on molecular mechanism of cardiovascular remodeling using genetically-engineered animals

我们一直在研究心脏和血管内产生的血管活性物质(心血管激素)在心血管重塑中的作用，并提出了心血管内分泌和代谢的概念。我们阐明了ANP和BNP分别由心脏的心房和心室分泌，而CNP是由内皮细胞分泌的，是一种内皮衍生的血管舒张肽。我们的合作研究人员还解释说，血管产生强大的血管收缩因子，血管紧张素II和内皮素。我们还克隆了利钠肽、血管紧张素II和内皮素的受体。在本研究中，我们建立了这些心血管激素及其受体的基因工程动物，即基因敲除小鼠(K/O)和转基因小鼠(TG)，并交叉杂交，以了解这些物质在心血管重塑中的相互作用。我们开发并拥有BNP TG、BNP K/O、CNP TG、CNP K…More/O、GC-A(心钠素和脑钠素受体)K/O、血管紧张素受体1型和2型K/O、A型和B型K/O、BNP K/O可诱导严重的心肌纤维化，并上调血管紧张素转换酶、转化生长因子-β3和I型胶原的基因表达。结果表明，BNP作为心脏局部抗纤维化因子发挥作用。BNP-TG表现为骨延长和血压降低。BNP-TG与GC-A K/O杂交，引起心肌肥大和血压升高，BNP-TG/GC-A K/O既保留了血压升高和心肌肥大的表型，又表现出较长的骨延长。这一结果提示BNP对不同组织的利钠肽受体亚型具有不同的激活作用。BNP-TG在肾损伤较重时肾损害较轻，提示利钠肽对肾脏有保护作用。CNP K/O引起侏儒症，软骨骨化受损，并出现早期死亡。开发了带有II型胶原启动子的CNP TG，其中CNP在软骨生长板中特异性地过表达。当CNP-K/O与CNP-TG交叉杂交时，骨异常消除，小鼠存活。利用这一CNP K/O/CNP TG，我们正在研究CNP在血管重塑中的作用。较少

We have been investigating the role of vasoactive substances produced within the heart and blood vessels (cardiovascular hormones) in cardiovascular remodeling and proposed the concept of "cardiovascular endocrinology and metabolism". We elucidated that ANP and BNP are secreted from the atrium and the ventricle of the heart, respectively, while CNP is secreted from the endothelial cell to act as an endothelium-derived vasorelaxing peptide. Our co-investigators also elucidated that the blood vessels produce potent vasoconstrictors, angiotensin II and endothelin. We also cloned the receptors for natriuretic peptides, angiotensin II and endothelin. In the present research, we developed genetically engineered animals, that is, knock-out mice (K/O) and transgenic mice (Tg) for these cardiovascular hormones and their receptors, and cross-bled them to see the interaction of these substances for cardiovascular remodeling in cooperation. We developed and possesses BNP Tg, BNP K/O, CNP Tg, CNP K … More /O, GC-A (the receptor for ANP and BNP) K/O, angiotensin receptor type 1 and type 2 K/O, endothelin receptor type A and type B K/O.BNP K/O elicited severe cardiac fibrosis with the up-regulation of the gene expression of angiotensin converting enzyme, TGF-β3 and collagen type I.Aortic banding of BNP K/O significantly enhanced the fibrosis. The results indicate the role of BNP as the anti-fibrotic cardiac local factor. BNP Tg exhibited long bone elongation and decreased blood pressure. When BNP Tg were cross-bled with GC-A K/O, which elicited cardiac hypertrophy and increase of blood pressure, obtained BNP Tg/GC-A K/O retained the phenotype of increased blood pressure and cardiac hypertrophy, but also exhibited long bone elongation. This result suggests the differential activation of BNP for natriuretic peptide receptor subtypes in different tissues. BNP Tg showed less significant renal damage, when the kidney was severely-injuried, suggesting the protective role of natriuretic peptides in the kidney. CNP K/O elicited dwarfism with impairment of enchondral ossification and exhibited early death. CNP Tg with collagen type II promotor, in which CNP is specifically over-expressed in the chondral growth plate, was developed. When CNP K/O were cross-bled with CNP Tg, the bone abnormality was abolished and the mice survived. Using this CNP K/O/CNP Tg, we are investigating the role of CNP in vascular remodeling. Less