Laboratory of GPCR Pathophysiology Research, Endocrinology and Metabolism, Clinical Sciences Research Institute, Warwick Medical School, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK.
Mol Cell Endocrinol. 2011 Jan 30;332(1-2):213-20. doi: 10.1016/j.mce.2010.10.013. Epub 2010 Oct 28.
Differentiation of human placental mononuclear trophoblasts into a multinucleate syncytium involves up-regulation of key proteins promoting cell fusion and increased capacity for placental hormonogenesis. It is well established that the activation of adenylyl cyclase leads to increased expression of trophoblast fusogenic gene machinery and human chorionic gonadotropin (hCG) secretion. We used the forskolin-induced syncytialisation of BeWo choriocarcinoma cells as a model to characterise in detail the signalling pathway downstream of adenylyl cyclase. Forskolin treatment induced a rapid and potent ERK1/2 and p38MAPK phosphorylation; this cascade required PKA-AKAP interactions and led to downstream CREB-1/ATF-1 phosphorylation via ERK1/2-dependent but p38MAPK-independent mechanisms. Interestingly both p38MAPK and ERK1/2 were involved in forskolin-induced hCG-secretion, suggesting the presence of additional p38MAPK-dependent but CREB-1/ATF-1-independent pathways. Forskolin treatment of BeWo cells significantly up-regulated the expression of various fusogenic gene mRNAs, including syncytin-1 and -2 (by 3- and 10-fold, respectively) the transcription factors old astrocyte specifically induced substance (OASIS) and glial cells missing a (GCMa) (by 3- and 6-fold, respectively) and the syncytin-2 receptor, major facilitator superfamily domain containing 2 (MFSD2) (by 2-fold). Up-regulation of AKAP79 and AKAP250 (by 2.5- and 4-fold, respectively) was also identified in forskolin-treated BeWo cells. Forskolin effects on all these genes were suppressed by chemical inhibition of p38MAPK whereas only specific genes were sensitive to ERK1/2 inhibition. This data provide novel insights into the signalling molecules and mechanisms regulating fusogenic gene expression by the adenylyl cyclase pathway.
人胎盘单核滋养细胞分化为多核合胞体涉及关键蛋白的上调，促进细胞融合和胎盘激素生成能力增加。众所周知，腺苷酸环化酶的激活导致滋养细胞融合基因机制和人绒毛膜促性腺激素（hCG）分泌的增加。我们使用福司可林诱导的绒毛膜癌细胞融合来作为模型，详细描述腺苷酸环化酶下游的信号通路。福司可林处理诱导了快速而强烈的 ERK1/2 和 p38MAPK 磷酸化；该级联反应需要 PKA-AKAP 相互作用，并通过 ERK1/2 依赖性但 p38MAPK 非依赖性机制导致下游 CREB-1/ATF-1 磷酸化。有趣的是，p38MAPK 和 ERK1/2 都参与了福司可林诱导的 hCG 分泌，表明存在其他 p38MAPK 依赖性但 CREB-1/ATF-1 非依赖性途径。福司可林处理 BeWo 细胞显著上调各种融合基因 mRNA 的表达，包括 syncytin-1 和 -2（分别增加 3 倍和 10 倍）、转录因子 old astrocyte specifically induced substance (OASIS) 和 glial cells missing a (GCMa)（分别增加 3 倍和 6 倍）和 syncytin-2 受体 major facilitator superfamily domain containing 2 (MFSD2)（增加 2 倍）。在福司可林处理的 BeWo 细胞中，还发现 AKAP79 和 AKAP250 的上调（分别增加 2.5 倍和 4 倍）。p38MAPK 的化学抑制抑制了福司可林对所有这些基因的作用，而仅特定基因对 ERK1/2 抑制敏感。这些数据为调节腺苷酸环化酶途径融合基因表达的信号分子和机制提供了新的见解。
