靶向整合素β3信号逆转睾丸间质干细胞衰老的研究

The senescence of stem cells is crucial to organismal aging. However, there is still a lack of study on the senescence of stem Leydig cell (SLC). We have demonstrated that hyperactivation of JAK/STAT signal results in the senescence of SLC by up-regulating integrin β3 signal. Moreover, knockdown of integrin β3 by siRNA rejuvenate senescence in SLC by inhibiting JAK/STAT signal. Accordingly, we hypothesized that there is a cross-talking between JAK/STAT signal and integrin β3 signal, which contributes to senescence of SLC. This study is aim to identify the binding sites between JAK/STAT and integrin β3 signal by Co-IP and RNA-sequence, to confirm the role of the cross-talking between JAK/STAT and integrin β3 signal in the senescence of SLC，to explore whether targeting integrin β3 signal could improve therapeutic effects of transplanted SLC which were isolated from aged mouse testis on hypgonadism, to further explore whether targeting integrin 3β signal can rejuvenate senescent SLC and even aged testis in vivo. All these findings may not only help to promote the clinical application of SLC transplantation, to reveal molecular and cellular mechanisms of the senescence of SLC, but also shed light on new strategies for anti-aging of testis, such as the treatment of Late-onset hypogonadism.

干细胞衰老对器官衰老至关重要，但缺乏睾丸间质干细胞（SLC）衰老的研究。本课题组前期研究发现JAK/STAT信号过度激活导致整合素β3上调，是SLC衰老的重要原因；并发现，下调整合素β3可抑制JAK/STAT信号的活化进而逆转SLC衰老。据此，我们认为SLC衰老存在“JAK/STAT-整合素β3”环路。本研究拟采用Co-IP、RNA-sequence等技术，明确JAK/STAT信号和整合素β3信号之间的结合位点；证实“JAK/STAT-整合素β3”环路介导SLC衰老的分子机制；探索靶向整合素β3信号预处理能否提高老年SLC移植对性腺功能减退症的治疗效果；进一步探索体内靶向整合素β3信号是否能够逆转SLC及睾丸衰老。研究结果将有助于促进人类SLC移植的临床转化和揭示SLC衰老的分子机制，并为迟发型性腺功能减退症等睾丸衰老性疾病的治疗提供新的思路。

男性性腺功能减退症严重影响男性生育和病人生活质量，但无理想疗法。外源性睾酮补充虽可以缓解男性性腺功能减退症的部分症状，但也有抑制生精、诱发心血管疾病和肿瘤等严重副作用。由于在维持睾丸组织稳态中的关键作用，睾丸间质干细胞在男性性腺功能减退症的治疗中具有巨大应用前景。本项目大方向是间质干细胞疗法在男性性腺功能减退症的应用及作用机制研究，细节方向聚焦在睾丸间质干细胞对免疫稳态的维持机制及相应靶向疗法的研发。.申请人团队在前期研究的基础上，发现整合素β3在睾丸间质干细胞及睾丸衰老中可能发挥重要作用。我们进一步发现与骨髓来源间质干细胞相比，睾丸间质干细胞对急性男性性腺功能减退症睾丸扭转具有更加优越治疗效果，可以恢复模型动物的睾酮分泌和生育能力；机制上，睾丸间质干细胞可主动识别微环境异常并通过线粒体传递抑制激活巨噬细胞的线粒体功能失调，是睾丸间质干细胞重构免疫稳态，治疗男性性腺功能减退症（包括睾丸扭转和睾丸衰老）的重要机制。申请人团队还发现通过基因工程技术过表达趋化因子受体CCR2以及疾病特异的炎症因子IL-1β预处理可提高间质干细胞靶向归巢和免疫重塑能力。申请人团队还发现靶向抑制睾丸巨噬细胞NLRP3炎症小体、淫羊藿次苷II和龟龄集可改善睾丸微环境，激活内源性干细胞，提高模型动物的睾酮合成和生精能力。.综上所述，通过本项目的实施，申请人团队探索了睾丸间质干细胞衰老和睾丸间质干细胞疗法在治疗男性性腺功能减退症中的机制，并揭示了睾丸间质干细胞与免疫动态交互调控在维持睾丸组织稳态，重塑睾丸免疫微环境中的关键作用。这些研究成果为间质干细胞疗法的优化，基于间质干细胞疗法男性性腺功能减退症新靶点的研发提供了重要依据，具有潜在的临床应用价值。