科學家們都知道切斷機體的晝夜節律可以負向影響機體的化學作用,實際上,被夜班打亂作息周期的工人們更易於患慢性炎症疾病,比如糖尿病、肥胖甚至癌症。
近日,來自索爾克研究所的研究人員發現了一種聯繫晝夜節律紊亂和增加的炎症效應的分子,缺失了生物鐘組分隱花色素(CRY)可以導致信號系統的激活,進而增加機體炎症分子的水平。相關研究成果刊登在了近日的國際雜誌PNAS上。
隱花色素(CRY)充當了節點的作用,來緩解生物鐘活性,向生物機體傳遞信號;早晨,CRY就會停止抑制生物鐘效應,幫助機體恢復效應來應對新的一天。為了深入研究生物鐘組分在免疫功能中扮演的角色,研究者測定了缺失CRY基因的小鼠大腦下丘腦炎症介質的表達效應,通過一系列的實驗,結果表明CRY缺失的小鼠機體中特定炎症蛋白的水平發生了明顯的增加。
研究者Panda表示,我們的研究發現揭示了缺乏CRY可以激活某些促炎分子,揭示出了隱花色素在調節炎症細胞因子表達上的作用。同時研究者發現缺失隱花色素也可以激活NF-kB途徑,前期研究揭示了抑制該途徑或許是某些疾病的合適治療方法,比如NF-kB可以在某些癌症如多發性骨髓瘤中被激活,這將影響骨髓中抵禦感染的漿細胞,使其不斷增殖。最後研究者表示,目前的目標是找出如何在短期內抑制NF-kB活性來治療像糖尿病等疾病。(生物谷Bioon.com)
編譯自:Molecular Link Between Circadian Clock Disturbances and Inflammatory Diseases Discovered
Circadian clock protein cryptochrome regulates the expression of proinflammatory cytokines
Rajesh Narasimamurthya, Megumi Hatorib, Surendra K. Nayakb, Fei Liua, Satchidananda Pandab,1, and Inder M. Vermaa,1
Chronic sleep deprivation perturbs the circadian clock and increases susceptibility to diseases such as diabetes, obesity, and cancer. Increased inflammation is one of the common underlying mechanisms of these diseases, thus raising a hypothesis that circadian-oscillator components may regulate immune response. Here we show that absence of the core clock component protein cryptochrome (CRY) leads to constitutive elevation of proinflammatory cytokines in a cell-autonomous manner. We observed a constitutive NF–κB and protein kinase A (PKA) signaling activation in Cry1−/−;Cry2−/− cells. We further demonstrate that increased phosphorylation of p65 at S276 residue in Cry1−/−;Cry2−/− cells is due to increased PKA signaling activity, likely induced by a significantly high basal level of cAMP, which we detected in these cells. In addition, we report that CRY1 binds to adenylyl cyclase and limits cAMP production. Based on these data, we propose that absence of CRY protein(s) might release its (their) inhibition on cAMP production, resulting in elevated cAMP and increased PKA activation, subsequently leading to NF–κB activation through phosphorylation of p65 at S276. These results offer a mechanistic framework for understanding the link between circadian rhythm disruption and increased susceptibility to chronic inflammatory diseases.