Estrogen receptor alpha and beta differentially mediate C5aR agonist evoked Ca²⁺-influx in neurons through L-type voltage-gated Ca²⁺ channels

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• 作者：Imre Farkas^a ; ^{farkas@koki.hu} ; Mikló ; s Sá ; rvá ; ri^a ; Má ; té ; Aller^b ; Noriko Okada^c ; Hidechika Okada^d ; Istvá ; n Likó ; ^e ; Zsolt Liposits^a ; ^f
• 关键词：C ; complement system ; C5aR ; &ldquo ; classical&rdquo ; complement 5a receptor (G-protein coupled) ; C5L2 ; &ldquo ; second&rdquo ; complement 5a receptor (non-G-protein coupled) ; CPA ; cyclopiazonic acid ; DPN ; diarylpropionitrile ; E2 ; 17尾-estradiol ; ER伪 ; estroge
• 刊名：Neurochemistry International
• 出版年：2012
• 期刊代码：120_01970186
• 类别：bio
• 出版时间：May, 2012
• 卷：60
• 期：6
• 页码：631-639
• 文件大小：890 K

摘要

Complement C5a is associated primarily with inflammation. The widespread expression of its receptors, C5aR and C5L2 in neuronal cells, however, suggests additional regulatory roles for C5a in the CNS. C5aR agonist (PL37-MAP) evokes Ca²⁺-influx in GT1-7 neuronal cell line and the Ca²⁺-influx is regulated by estradiol. In the present study, we examined further the mechanism of Ca²⁺-influx and the contribution of the two estrogen receptor (ER) isotypes, ER伪 and ER尾, to estrogenic modulation of intracellular Ca²⁺-content. GT1-7 neurons were treated with isotype selective ER agonists for 24 h then C5aR agonist evoked Ca²⁺-responses were measured by Ca²⁺-imaging. Transcriptional changes were followed by real-time PCR. We found that not only estradiol (100 pM), but the ER伪 selective agonist PPT (100 pM) enhanced the PL37-MAP-evoked Ca²⁺-influx (E2: 215%, PPT: 175%, compared to the PL37-MAP-evoked Ca²⁺-influx). In contrast, the ER尾 selective agonist DPN (100 pM) significantly reduced the Ca²⁺-influx (32%). Attenuated Ca²⁺-response (25%) was observed in Ca-free environment and depletion of the Ca²⁺-pool by CPA eliminated the remaining elevation in the Ca²⁺-content, demonstrating that the majority of Ca²⁺ originated from the extracellular compartment. L-type voltage-gated Ca²⁺-channel (L-VGCC) blocker nifedipine abolished the Ca²⁺-influx, while R-type Ca²⁺-channel blocker SNX-482 had no effect, exemplifying the predominant role of L-VGCC in this process. Acute pre-treatments (8 min) with ER agonists did not affect the evoked Ca²⁺-influx, revealing that the observed effects of estrogens were genomic. Therefore, we checked estrogenic regulation of C5a receptors and L-VGCC subunits. ER agonists increased C5aR mRNA expression, whereas they differentially regulated C5L2. Estradiol decreased transcription of Ca_v1.3 L-VGCC subunit. Based on these results we propose that estradiol may differentially modulate C5a-induced Ca²⁺-influx via L-VGCCs in neurons depending on the expression of the two ER isotypes.