Dosiou C, Hamilton A E, Pang Y, Overgaard M T, Tulac S, Dong J, Thomas P, Giudice L C
Division of Endocrinology and Metabolism, Department of Medicine, Stanford University, Stanford, California 94305, USA.
J Endocrinol. 2008 Jan;196(1):67-77. doi: 10.1677/JOE-07-0317.
Although there is significant evidence for progesterone's role as an immunomodulator, nuclear progesterone receptors have not been consistently identified in immune cells. Recently, three new putative membrane progesterone receptors (mPRs), mPRalpha, mPRbeta, and mPRgamma have been described. The objective of this study was to examine whether mPRs are expressed in peripheral blood leukocytes (PBLs) in women of reproductive age, and to further characterize them in T lymphocytes and immortalized T cells (Jurkat cells). Transcripts for mPRalpha and mPRbeta but not mPRgamma, were detected by RT-PCR in PBLs, T lymphocytes, and Jurkat cells. Western blot analysis showed the presence of the mPRalpha and mPRbeta proteins on cell membranes of T lymphocytes and Jurkat cells. Expression of the mPRalpha mRNA was upregulated in the luteal phase of the menstrual cycle in cluster of differentiation (CD)8+, but not in CD4+, T lymphocytes. Radioreceptor assays revealed specific [(3)H]progesterone binding to T- and Jurkat cell membranes (K(d) 4.25 nM) characteristic of steroid membrane receptors. Progesterone activated an inhibitory G-protein (G(i)), suggesting that mPRs are coupled to G(i) in Jurkat cells. These results suggest a potential novel mechanism for progesterone's immunoregulatory function through activation of mPRs.
尽管有大量证据表明孕酮具有免疫调节作用，但在免疫细胞中尚未一致鉴定出核孕酮受体。最近，已描述了三种新的假定膜孕酮受体（mPRs），即mPRα、mPRβ和mPRγ。本研究的目的是检测mPRs在育龄女性外周血白细胞（PBLs）中是否表达，并在T淋巴细胞和永生化T细胞（Jurkat细胞）中进一步对其进行表征。通过RT-PCR在PBLs、T淋巴细胞和Jurkat细胞中检测到了mPRα和mPRβ的转录本，但未检测到mPRγ的转录本。蛋白质印迹分析显示在T淋巴细胞和Jurkat细胞的细胞膜上存在mPRα和mPRβ蛋白。在月经周期的黄体期，分化簇（CD）8 + 而非CD4 + T淋巴细胞中mPRα mRNA的表达上调。放射受体分析显示特异性的[³H]孕酮与T细胞和Jurkat细胞膜结合（解离常数K(d)为4.25 nM），这是类固醇膜受体的特征。孕酮激活了一种抑制性G蛋白（G(i)），表明mPRs在Jurkat细胞中与G(i)偶联。这些结果提示了孕酮通过激活mPRs发挥免疫调节功能的一种潜在新机制。
