Ge Chutian, Yu Minli, Petitte James N, Zhang Caiqiao
Key Laboratory of Animal Epidemic Etiology & Immunological Prevention of the Ministry of Agriculture, College of Animal Sciences, Zhejiang University, Hangzhou, People's Republic of China.
Biol Reprod. 2009 Mar;80(3):528-36. doi: 10.1095/biolreprod.108.072728. Epub 2008 Nov 12.
Epidermal growth factor (EGF) has been shown to stimulate survival in diverse cells in vitro. In the present study, the effects of EGF and the EGF-related signaling pathway on proliferation of chicken primordial germ cells (PGCs) were investigated. Results showed that EGF (10-100 ng/ml) increased the number and area of PGC colonies in a time- and dose-dependent manner. EGF also activated PKC, a process that was inhibited by AG1478 (an EGFR tyrosine kinase inhibitor) and ethyleneglycol-bis-(beta-aminoethyl ether)-N,N'-tetraacetic acid (EGTA; an intracellular Ca(2+) chelator). In addition, the degradation of NFKBIA and NFKB1 (p65) translocation was observed after EGF treatment, which was significantly blocked by pretreatment with AG1478, EGTA, H(7), or SN50 (NFKB1-specific inhibitor). Furthermore, we found that EGF-induced cell proliferation was significantly attenuated by AG1478, EGTA, H(7), and SN50, respectively. On the other hand, inhibition of EGFR, Ca(2+)/PKC, or NFKB1 abolished the EGF-stimulated increase in the expression of cyclins CCND1 and CCNE1, cyclin-dependent kinase 6 (CDK6), CDK2, and BCL2, and restored the EGF-induced inhibition of BAX expression and caspase 3/9 activity, indicating that EGFR, PKC, and NFKB1 signaling cascades were involved in EGF-stimulated DNA synthesis and antiapoptosis action. In conclusion, EGF stimulated proliferation of chicken PGCs via activation of Ca(2+)/PKC involving NFKB1 signaling pathway. These observations suggest that EGF signaling is important in regulating germ cell proliferation in the chicken embryonic gonad.
表皮生长因子（EGF）已被证明在体外能刺激多种细胞的存活。在本研究中，研究了EGF及其相关信号通路对鸡原始生殖细胞（PGCs）增殖的影响。结果表明，EGF（10 - 100 ng/ml）以时间和剂量依赖性方式增加了PGC集落的数量和面积。EGF还激活了蛋白激酶C（PKC），这一过程被AG1478（一种表皮生长因子受体酪氨酸激酶抑制剂）和乙二醇双（β - 氨基乙醚）- N，N'-四乙酸（EGTA；一种细胞内Ca(2+)螯合剂）所抑制。此外,在EGF处理后观察到NFKBIA的降解和NFKB1（p65）的易位，这被AG1478、EGTA、H(7)或SN50（NFKB1特异性抑制剂）预处理显著阻断。此外，我们发现AG1478、EGTA、H(7)和SN50分别显著减弱了EGF诱导的细胞增殖。另一方面，抑制表皮生长因子受体、Ca(2+)/PKC或NFKB1消除了EGF刺激的细胞周期蛋白CCND1和CCNE1、细胞周期蛋白依赖性激酶6（CDK6）、CDK2和BCL2表达的增加，并恢复了EGF诱导的BAX表达抑制和半胱天冬酶3/9活性，表明表皮生长因子受体、PKC和NFKB1信号级联参与了EGF刺激的DNA合成和抗凋亡作用。总之，EGF通过激活涉及NFKB1信号通路的Ca(2+)/PKC刺激鸡PGCs的增殖。这些观察结果表明，EGF信号在调节鸡胚胎性腺中的生殖细胞增殖中很重要。
