Identification of novel catechin receptor that mediates blood vessel protective effect and vasodilatation, and it's application for functional food

通过初步研究，我们发现(+)-儿茶素对血管内皮细胞有扩张作用。这种作用是在体内用(+)-儿茶素处理后30分钟内观察到的，而不是(-)-表没食子儿茶素没食子酸酯。我们假设存在新的(+)-儿茶素特异性受体，这种作用是通过受体信号转导而产生的。为了鉴定(+)-儿茶素受体，我们在注射(+)-儿茶素的小鼠脑中使用了差异蛋白质组学方法。8周龄雄性ICR小鼠静脉注射100 mg/ml(+)-儿茶素。注射3h后，取脑匀浆提取蛋白质。提取的脑组织进行双向PAGE，二维凝胶进行银染。(+)-儿茶素注射组小鼠脑组织中等电点为~8.1、相对分子质量为~60 kDa、等电点为~8.3、相对分子质量为~17 kDa的斑点明显增加。而等电点为~5.7、相对分子质量为22 kDa的斑点减少。这些斑点的变化被怀疑是由翻译后修饰引起的，例如蛋白质磷酸化或假定受体本身或其下游信号分子的蛋白质降解。接下来，我们将尝试分离这些蛋白质斑点，并使用肽质量指纹图谱分析氨基酸序列。

From preliminary investigation, we found a vasodilatation effect of (+)-catechin on the endothrial cells. The effect was observed within 30 minutes after (+)-catechin treatment in vivo, but not (-)-epigallocatechin gallate, we hypothesized that the existence of novel (+)-catechin specific receptor and that the effect was mediated through the receptor signaling thereby produced NO. In order to identify putative (+)-catechin receptor, we used a differential proteomics approach in the brain of (+)-catechin injected mice. Male, 8-week-old ICR mice were injected 100 mg/ml (+)-catechin intravenously. After 3h injection, the brain was excised and homogenized to extract proteins. The brain extracts were subjected to 2-D PAGE, and then the 2-D gels were silver stained. The spots with a pI of 〜8.1 and a molecular mass of 〜60 kDa and a pI of 〜8.3 and a molecular mass of 〜17 kDa were markedly increased in (+)-catechin injected mouse brain extract compared with vehicle injected control. While the spot with a pI of 〜5.7 and a molecular mass of 22 kDa was decreased. These changes in spots are suspected to be brought about by the post-translational modification such as protein phosphorylation or protein degradation of the putative receptor itself or its downstream signaling molecules. Next, we will try to isolate these protein spots and analyze the amino acid sequences using peptide mass fingerprinting.