CRH介导的妊娠期慢性应激致子代抑郁的机制研究

Adverse experiences during early life can potentially impact a broad range of disease in offsprings of human. For example, chronic stress during gestation can result in a reduction in birth weight and subsequently increase the likelihood of disorders of cardiovascular function, glucose homeostasis, dysregulation of hypothalamic–pituitary–adrenal (HPA) axis in offspring. Whether chronic stress during gestation could affect the onset of depression in offsprings is not determined. Previous studies showed that chronic stress during gestation could increase the level of Corticotropin-Releasing Hormone(CRH) that is considered to be related with the onset of depression in offsprings. Therefore, we will use the“China-Anhui Birth Cohort Study”to investigate the relationship among the chronic stress during gestation, the level of CRH and the depression in offsprings. In order to determine whether chronic stress during gestation-inducing the depression in offspring is mediated by CRH, hippocampal and amygdala CRH receptor1（CRHR1） gene conditional knockout mice will be used, or CRHR1-antagonist NBI30775 will be infused into the lateral ventricle. On the other hand , previous work has demonstrated that N- Methyl-D-Aspartate Receptor (NMDAR)-mediated excitotoxicity is involved in depression, and CRH-mediated spine loss required the activation of NMDAR, therefore, NMDAR-antagonist will be infused into the lateral ventricle to determine whether chronic stress during gestation-inducing the depression of offsprings is also mediated by NMDAR. . Mammalian target of rapamycin(mTOR) signals regulate neuronal survival and differentiation, dendritic arborization, axonal growth, synaptogenesis, and synaptic plasticity. Blockade of mTOR signaling completely blocked ketamine-induction of synaptogenesis and behavioral responses in models of depression. In order to determine whether mTOR is the downstream signal of CRH and NMDAR , we will compare the levels of mTOR mRNA、mTOR and p-mTOR（Ser2448）protein among CRHR1 gene conditional knockout group、CRHR1-antagonist group、NMDAR-antagonist group and control group. At last, hippocampus section will be cultured to futher determine whether CRH-mediated the downregulation of mTOR involves NMDA receptor activation. These studies will help us to explore the relationship between early life environmental exposures and the onset of depression, which will be benefit for prevention and treatment of depression.

抑郁症是常见疾病，是否与生命早期不良经历有关？尚未确定。已知妊娠期慢性应激致子代HPA轴紊乱，使子代促肾上腺皮质激素释放激素（CRH）升高，而过高的CRH与抑郁有关。因此，本课题拟用“中国安徽出生队列”研究妊娠期慢性应激、CRH与子代儿童抑郁的关系；利用海马、杏仁核CRHR1条件性基因敲除鼠或向子鼠侧脑室注射CRHR1拮抗剂，观察子代抑郁以及前额皮层、海马和杏仁核的病理改变，阐明CRH是否介导妊娠期慢性应激致子代抑郁；利用向子鼠侧脑室注射NMDAR拮抗剂，研究NMDAR在子代抑郁中的作用；通过观察CRHR1基因敲除、CRHR1拮抗剂和NMDAR拮抗剂对子鼠前额皮层、海马和杏仁核mTOR的影响，阐明mTOR是否参与了CRH介导的子代抑郁；通过体外培养海马脑片，加入CRH和上述受体拮抗剂并检测mTOR，进一步确认CRH是否通过NMDAR抑制mTOR的激活。该研究将为寻找防治抑郁的新途径提供资料

抑郁症病因尚未完全阐明。近年研究显示：妊娠期慢性应激导致子代海马组织CRH水平显著升高；应激水平的CRH引起海马神经元损伤，焦虑抑郁程度增加，CRH受体1（R1）拮抗剂可以明显改善应激所致的上述变化；NMDAR拮抗剂可修复CRH引起的树突棘损伤，可以改善与树突生长有关的mTOR通路。故本课题组提出，妊娠期慢性应激可能是子代发生抑郁的重要危险因素；妊娠期慢性应激可能通过升高子代CRH，激动NMDAR，抑制mTOR通路，促进子代抑郁的发生。本课题研究了妊娠期慢性应激是否是子代抑郁发生的危险因素，妊娠期慢性应激是否通过升高的子代CRH激活NMDAR，抑制mTOR激活，从而引起子代抑郁。人群研究结果显示，妊娠期慢性应激是子代抑郁的一个危险因素。动物实验结果显示， 妊娠期慢性应激引起子代雄鼠抑郁，致子鼠海马CRH升高、海马和杏仁核细胞凋亡指数增加、树突损伤、P-mTOR/mTOR下降，但对P-AKT/AKT无影响；腹腔和侧脑室注射CRHR1拮抗剂能上调mTOR通路、改善子鼠海马和杏仁核病理损害和抑郁样行为，腹腔注射NMDAR拮抗剂也可上调mTOR通路，改善子鼠海马、杏仁核组织病理损伤和抑郁样行为。体外海马组织培养显示，CRH干预降低mTOR蛋白的表达，CRHR1和NMDAR拮抗剂上调mTOR表达。此外，为了进一步确定海马CRHR1是否介导妊娠期慢性应激致子代雄鼠抑郁，本研究采用海马条件性CRHR1基因敲除鼠，结果显示，海马CRHR1条件性基因敲除减轻妊娠期慢性应激致子代抑郁，减轻子代海马神经元损伤，改善子代海马异常的mTOR活性。 结果提示，妊娠期慢性应激可通过升高的CRH，激活NMDAR，抑制mTOＲ激活，引起海马、杏仁核神经元损伤，导致子代抑郁的发生。该研究为寻找新的预防和治疗抑郁的措施提供重要的基础资料。现已发表论文6篇，其中SCI论文2篇，另待发表SCI论文2篇。