BACKGROUND Calcitonin gene-related peptide (CGRP) contributes to bone formation by stimulating bone marrow stromal cell (BMSC) proliferation and differentiation. However, the proliferative and apoptotic effects of CGRP on bone marrow-derived endothelial progenitor cells (EPCs) have not been investigated. METHODS We tested the effects of CGRP on EPC proliferation and apoptosis by Cell Counting Kit-8, flow cytometry, and studied the effects of CGRP on the expression of proliferation- and apoptosis-related markers in EPCs and the underlying mitogen-activated protein kinase (MAPK) signalling pathway by quantitative polymerase chain reaction and western blotting. RESULTS We detected EPC markers (CD34, CD133 and VEGFR-2) in 7-day cultures and found that CGRP (10- 10-10- 12 M) promoted the proliferation of cultured EPCs, with a peak increase of 30% at 10- 10 M CGRP. CGRP also upregulated the expression of proliferation-associated genes, including cyclin D1 and cyclin E, and increased the percentages of G2/M-phase and S-phase cells after incubation 72 h. CGRP inhibited serum deprivation (SD)-induced apoptosis in EPCs after 24 and 48 h and downregulated the expression of apoptosis-related genes, including caspase-3, caspase-8, caspase-9 and Bax. Phosphorylated (p-)ERK1/2, p-p38 and p-JNK protein levels in EPCs treated with CGRP were significantly lower than those in untreated EPCs. Pre-treatment with the calcitonin receptor-like receptor (CRLR) antagonist CGRP8-37 or a MAPK pathway inhibitor (PD98059, SB203580 or SP600125) completely or partially reversed the pro-proliferative and anti-apoptotic effects and the reduced p-ERK1/2, p-p38 and p-JNK expression induced by CGRP. CONCLUSION Our results show that CGRP exerts pro-proliferative and anti-apoptotic effects on EPCs and may act by inhibiting MAPK pathways.

中文翻译：

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降钙素基因相关肽通过抑制 MAPK 信号促进内皮祖细胞增殖和抑制凋亡。

背景技术降钙素基因相关肽(CGRP)通过刺激骨髓基质细胞(BMSC)增殖和分化来促进骨形成。然而，尚未研究 CGRP 对骨髓来源的内皮祖细胞 (EPC) 的增殖和凋亡作用。方法 我们通过 Cell Counting Kit-8、流式细胞仪检测 CGRP 对 EPC 增殖和凋亡的影响，并研究 CGRP 对 EPCs 增殖和凋亡相关标志物的表达和潜在的丝裂原活化蛋白激酶的影响。 MAPK) 信号通路通过定量聚合酶链反应和蛋白质印迹。结果 我们在 7 天培养中检测到 EPC 标志物（CD34、CD133 和 VEGFR-2），发现 CGRP（10-10-10-12 M）促进了培养的 EPCs 的增殖，在 10-10 M CGRP 时峰值增加 30%。CGRP 还上调增殖相关基因的表达，包括细胞周期蛋白 D1 和细胞周期蛋白 E，并在孵育 72 小时后增加 G2/M 期和 S 期细胞的百分比。CGRP在24和48小时后抑制血清剥夺（SD）诱导的EPC细胞凋亡，并下调凋亡相关基因的表达，包括caspase-3、caspase-8、caspase-9和Bax。用 CGRP 处理的 EPC 中的磷酸化 (p-)ERK1/2、p-p38 和 p-JNK 蛋白水平显着低于未处理的 EPC。用降钙素受体样受体 (CRLR) 拮抗剂 CGRP8-37 或 MAPK 通路抑制剂（PD98059、SB203580 或 SP600125）预处理完全或部分逆转促增殖和抗凋亡作用以及降低的 p-ERK1/2 , CGRP 诱导的 p-p38 和 p-JNK 表达。结论 我们的研究结果表明，CGRP 对 EPCs 具有促增殖和抗凋亡作用，并且可能通过抑制 MAPK 通路发挥作用。