PPARγ mediates innate immunity by regulating the 1α,25-dihydroxyvitamin D3 induced hBD-3 and cathelicidin in human keratinocytes
PPARγ mediates innate immunity by regulating the 1α,25-dihydroxyvitamin D3 induced hBD-3 and cathelicidin in human keratinocytes
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DOI：
10.1016/j.jdermsci.2010.09.008
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发表时间：
2010-12-01
影响因子：
4.6
通讯作者：
Hashimoto, Koji
中科院分区：
文献类型：
--
作者：
Dai, Xiuju;Sayama, Koji;Hashimoto, Koji
背景：抗菌肽(AMPS)的产生是皮肤天然免疫抵抗感染的主要机制。激素活性维生素D3(1α，25-二羟基维生素D3；1，25D(3))是皮肤天然免疫的重要调节剂，已被证明能增加AMP的表达和功能。目的：PPARγ是一种配体激活的核受体，在角质形成细胞分化和皮肤动态平衡中发挥作用。在这项研究中，我们研究了1，25D(3)激活的PPARγ信号是否调节角质形成细胞中AMP的表达。用逆转录聚合酶链式反应(RT-PCR)和蛋白质印迹法(Western印迹)检测AMPs的mRNA和蛋白水平，用EMSA法检测PPAR-γ、VDRE和AP-1的DNA结合活性。为了检测PPAR-γ的作用，构建了携带显性-阴性PPAR-γ的重组腺病毒(dN-PPAR-γ)，并将其导入角质形成细胞。结果：1，25D(3)显著增强了角质形成细胞中HBD-3和长春花碱的表达。DN-PPARγ的表达不影响与维生素D反应元件(VDRE)的结合，而VDRE是VD3诱导放线菌素的关键；但它确实降低了1，25D(3)对HBD-3和放线菌素的诱导。抑制p38、ERK和JNK信号通路可阻断HBD-3的表达，而仅p38抑制可抑制长春花碱的诱导。DN-PPAR-γ对ERK和JNK活性无影响，但通过对FRA1和c-Fos蛋白的作用，抑制p38的磷酸化，抑制1，25D(3)诱导的AP-1的活化。结论：PPAR通过调节AP-1和p38的活性，调节1，25D(3)诱导的角质形成细胞HBD-3和趋化因子的表达。(C)2010年日本皮肤病研究学会。爱思唯尔爱尔兰有限公司出版。版权所有。
Background: Production of antimicrobial peptides (AMPS) is the primary mechanism by which skin innate immunity protects against infection. Hormonally active vitamin D3 (1 alpha,25-dihydroxyvitamin D3; 1,25D(3)) is a vital regulator of skin innate immunity, and has been shown to increase the expression and function of AMPs.Objective: PPAR gamma is a ligand-activated nuclear receptor and plays a role in keratinocyte differentiation and cutaneous homeostasis. In this study, we investigate whether 1,25D(3)-activated PPAR gamma signaling regulates AMP expression in keratinocytes.Methods: Subconfluent keratinocytes were treated with 1,25D(3) for the indicated times. The mRNA and protein levels of AMPs were detected by RT-PCR and Western blot, and the DNA binding activation of PPAR gamma, VDRE and AP-1 was investigated by EMSA. To examine the role of PPAR gamma, the recombinant adenovirus carrying a dominant-negative form of PPAR gamma (dn-PPAR gamma) was constructed and transfected into keratinocytes.Results: We show here that 1,25D(3) significantly enhances hBD-3 and cathelicidin expression in keratinocytes. Expression of dn-PPAR gamma did not affect binding to the vitamin D-responsive element (VDRE), which is crucial for cathelicidin induction by VD3; however, it did decrease 1,25D(3) induction of both hBD-3 and cathelicidin. Inhibition of the p38, ERK, and JNK signaling pathways blocked hBD-3 expression, whereas only p38 inhibition suppressed cathelicidin induction. dn-PPAR gamma had no effect on ERK and JNK activity, but inhibited p38 phosphorylation and suppressed 1,25D(3)-induced AP-1 activation via effects on Fra1 and c-Fos proteins.Conclusions: In conclusion, PPAR gamma regulates the 1,25D(3)-induced hBD-3 and cathelicidin expression in keratinocytes through the regulation of AP-1 and p38 activity. (C) 2010 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.