近日来自美国爱因斯坦医学院的研究人员在新研究中解析了下丘脑内IKK/NF-κB信号通路对机体代谢性稳态、肥胖及相关高血压病的影响。这一研究为治疗和预防人类肥胖相关高血压及心血管疾病指明了新方向。相关研究论文在线发表在6月5日的《自然—医学》(Nature medicine)杂志上。
领导这一研究的是著名华人学者蔡东升博士,其早年毕业于南京医科大学,2000年于上海交通大学获得博士学位,现为美国爱因斯坦医学院分子药理学系副教授,主要的研究领域为代谢平衡和代谢失序中的炎症及应激研究。
在早年的研究中,蔡东升博士发现代谢炎症可以影响机体的高级中枢神经细胞,尤其是下丘脑(hypothalamus)。这个大脑结构是调控饮食和能量平衡的一个关键调控元素,同时也掌控着周边组织的代谢。然而一直以来研究人员对于下丘脑在包括肥胖及相关代谢疾病中所扮演的角色知之甚少。
在去年蔡东升博士发表于Cell杂志上的一篇文章中,首次发现下丘脑的特异性神经细胞中存在IKKbeta/NF-kappaB,而且这一途径在下丘脑中,比周边组织存在得更多,通常在大脑中保持非激活的状态。研究人员发现通过高脂肪喂食发生营养过剩会激发IKKbeta/NF-kappaB,尤其是在下丘脑的神经细胞。抑制这一信号通路则会降低动物能量过度消耗,肥胖增加的风险。
之后蔡东升研究小组将研究焦点放置了在探索IKKbeta/NF-kappaB信号通路与其他途径的关系,以及调节IKK/NF-κB信号通路对机体代谢性稳态、肥胖及相关疾病的影响上。
高血压病是目前全球最大的流行病之一,也是最常见的心血管疾病的主要风险因子。高血压指在静息状态下动脉收缩压和/或舒张压增高(>=140/90mmHg),常伴有脂肪和糖代谢紊乱以及心、脑、肾和视网膜等器官功能性或器质性改变。目前临床上有很多肥胖型高血压病人且常伴有糖尿病。
在新文章中,研究人员解析了下丘脑IKK/NF-κB信号通路对于肥胖相关性高血压的影响。研究人员证实快速激活内侧基底下丘脑IKK/NF-κB信号通路可导致实验小鼠的血压快速增高。研究人员发现当丘脑细胞中的NF-κB活性受到抑制时可抵消肥胖所致的高血压。此外,研究人员证实促阿片黑皮苏前体(POMC)神经元在下丘脑IKK-β 和 NF-κB激活导致的高血压效应中起关键性的作用。研究结果表明内侧基底下丘脑尤其是下丘脑POMC 神经元中IKK-β 和NF-κB激活是联系肥胖与高血压首要致病因素。这一研究发现为预防及治疗肥胖相关的高血压和心血管疾病指明了新方向。(生物谷Bioon.com)
生物谷推荐原文出处:
Nature Medicine DOI:10.1038/nm.2372
Uncoupling the mechanisms of obesity and hypertension by targeting hypothalamic IKK-[beta] and NF-[kappa]B
Sudarshana Purkayastha; Guo Zhang; Dongsheng Cai
Obesity-related hypertension has become an epidemic health problem and a major risk factor for the development of cardiovascular disease (CVD). Recent research on the pathophysiology of obesity has implicated a role for the hypothalamus in the pathogenesis of this condition1, 2, 3. However, it remains unknown whether the often-seen coupling of hypertension with obesity can also be explained by hypothalamic dysfunction, despite the emerging appreciation that many forms of hypertension are neurogenic in origin4, 5, 6, 7, 8, 9, 10, 11, 12, 13. Our studies here revealed that acute activation of the proinflammatory protein nuclear factor κB (NF-κB) and its upstream activator IκB kinase-β (IKK-β, encoded by Ikbkb) in the mediobasal hypothalamus rapidly elevated blood pressure in mice independently of obesity. This form of hypothalamic inflammation-induced hypertension involved the sympathetic upregulation of hemodynamics and was reversed by sympathetic suppression. Loss-of-function studies further showed that NF-κB inhibition in the mediobasal hypothalamus counteracted obesity-related hypertension in a manner that was dissociable from changes in body weight. In addition, we found that pro-opiomelanocortin (POMC) neurons were crucial for the hypertensive effects of the activation of hypothalamic IKK-β and NF-κB, which underlie obesity-related hypertension. In conclusion, obesity-associated activation of IKK-β and NF-κB in the mediobasal hypothalamus—particularly in the hypothalamic POMC neurons—is a primary pathogenic link between obesity and hypertension. Breaking this pathogenic link may represent an avenue for controlling obesity-related hypertension and CVD without requiring obesity control.