Council for Scientific and Industrial Research - Institute of Genomics and Integrative Biology, Delhi 110007, India.
Proc Natl Acad Sci U S A. 2014 Feb 11;111(6):2301-6. doi: 10.1073/pnas.1304988111. Epub 2014 Jan 28.
Cellular homeostasis is an outcome of complex interacting processes with nonlinear feedbacks that can span distinct spatial and temporal dimensions. Skin tanning is one such dynamic response that maintains genome integrity of epidermal cells. Although pathways underlying hyperpigmentation cascade are recognized, negative feedback regulatory loops that can dampen the activated melanogenesis process are not completely understood. In this study, we delineate a regulatory role of IFN-γ in skin pigmentation biology. We show that IFN-γ signaling impedes maturation of the key organelle melanosome by concerted regulation of several pigmentation genes. Withdrawal of IFN-γ signal spontaneously restores normal cellular programming. This effect in melanocytes is mediated by IFN regulatory factor-1 and is not dependent on the central regulator microphthalmia-associated transcription factor. Chronic IFN-γ signaling shows a clear hypopigmentation phenotype in both mouse and human skin. Interestingly, IFN-γ KO mice display a delayed recovery response to restore basal state of epidermal pigmentation after UV-induced tanning. Together, our studies delineate a new spatiotemporal role of the IFN-γ signaling network in skin pigmentation homeostasis, which could have implications in various cutaneous depigmentary and malignant disorders.
细胞内稳态是复杂相互作用过程的结果,具有非线性反馈,可以跨越不同的时空维度。皮肤晒黑就是这样一种维持表皮细胞基因组完整性的动态反应。虽然已经认识到了导致色素沉着级联反应的途径,但对于可以抑制激活的黑色素生成过程的负反馈调节环路还不完全了解。在这项研究中,我们描述了 IFN-γ 在皮肤色素生物学中的调节作用。我们表明,IFN-γ 信号通过几个色素基因的协同调节,阻碍关键细胞器黑素体的成熟。IFN-γ 信号的撤回会自发恢复正常的细胞编程。这种在黑素细胞中的作用是由 IFN 调节因子 1 介导的,不依赖于中央调节因子小眼畸形相关转录因子。慢性 IFN-γ 信号在小鼠和人类皮肤中均表现出明显的色素减退表型。有趣的是,IFN-γ KO 小鼠在 UV 诱导晒黑后恢复表皮色素基础状态的反应延迟。总之,我们的研究描绘了 IFN-γ 信号网络在皮肤色素稳态中的新的时空作用,这可能对各种皮肤脱色和恶性疾病有影响。