The physiological role of CD9 and exosomes in oviducts and uteri

在哺乳动物中，雌性生殖道在整个成年生活中都会周期性地重塑。尽管CD9在子宫上皮细胞中表达，但其作用尚不清楚。在这里，我们通过检测受精能力的CD9-/-小鼠在它们的卵子中表达CD9-GFP(CD9-/-TG)来解决这个问题。免疫组织化学分析证实CD9存在于子宫分泌物中。电子显微镜分析揭示了CD9结构的细胞外基质样特征。我们还发现，CD9-/-TG雌性小鼠在第一次出生后产仔数显著减少。组织学分析显示，无论是在体外还是在体内，小鼠子宫内膜再上皮化都严重延迟。CD9-/-TG雌性小鼠血管内皮生长因子-A(VEGF-A)含量显著降低。这些结果首次证明CD9介导的血管内皮生长因子分泌在子宫再上皮化中起作用。

In mammals, the female reproductive tract is remodeled cyclically throughout adult life. Despite the expression of CD9 in the epithelium of the uterus, its role is unclear. Here, we addressed this issue by examining fertilization-competent Cd9-/- mice expressing CD9-GFP in their eggs (Cd9-/-TG). Immunobiochemical analysis demonstrated that CD9 was present in the uterine secretions. Electron microscopic analysis revealed the extracellular matrix-like feature of CD9-containing structures. We also found that the litter size of Cd9-/-TG female mice was significantly reduced after their first birth. Histological analysis revealed severely delayed re-epithelialization of the endometrium both in vitro and in vivo in mice. The quantity of vascular endothelial growth factor-A (VEGF-A) was remarkably reduced in Cd9-/-TG female mice. These results provide the first evidence that CD9-mediated VEGF secretion plays a role in re-epithelialization of the uterus.