组织炎症相关T淋巴细胞亚群在调控良性前列腺增生信号网络中的作用及机制研究

Benign prostatic hyperplasia (BPH) is one of most common diseases happened in elderly men, however, its pathogenesis is still unclear. Previous studies demonstrated that chronic inflammation played a crucial role in the occurrence and progression of BPH. Our previous research found that the proportion of BPH with tissue inflammation amounted to 95.6%, and T lymphocytes widely existed in BPH tissue with inflammatory. BPH with tissue inflammatory has lower CD4+T/CD8+T ratio than that without inflammation. Therefore，we suspected that there is a close relationship between T lymphocytes and BPH. According to the previous achievement, we hypothesized that: influenced by the estrogen/androgen imbalance and so on, T lymphocytes infiltrated into the prostate tissue and stimulated prostate cells through activating the related inflammation signal pathways; furthermore, T lymphocytes and prostate cells formed a special micro-environment which could induce more T lymphocytes infiltrating into prostate and expand the degree of inflammation and ultimately lead to BPH. Therefore，in this project, we strive to use varied BPH patients specimens and BPH animal model to explore the distribution and proportion of subgroups of T lymphocytes at different stages of BPH tissue inflammation and to supervise the dynamic changes of inflammation-related cytokines. In addition, we also try to investigate the effects and mechanisms of T lymphocytes and inflammation-related cytokines and its relevant signal pathways in BPH through clinical specimens and animal models as well as molecular and cellular experiments.

良性前列腺增生(BPH)是老年男性的最常见疾病之一，发病机制不明。研究证实慢性组织炎症在BPH发生发展中扮演着重要角色。课题组研究发现BPH伴有组织炎症者高达95.6%，且T淋巴细胞浸润广泛存在于伴组织炎症的BPH组织中；与不伴组织炎症组相比，伴有组织炎症的BPH中CD4+/CD8+T细胞比值显著降低，可推测T淋巴细胞与BPH关系密切。结合前期研究，本课题假设：在雌雄激素失衡等影响下，T淋巴细胞浸润前列腺组织并通过相关炎症信号通路的激活而刺激前列腺细胞，并与之形成特殊的微环境，进一步招募T淋巴细胞浸润至前列腺组织内并扩大炎症最终导致BPH。因此，本课题拟通过BPH患者及动物模型，研究BPH组织炎症不同时期T淋巴细胞亚群比例及分布和炎症相关细胞因子的动态变化；并通过细胞分子水平及临床组织标本和动物模型水平，研究参与前列腺组织炎症介导的T淋巴细胞及特异细胞因子与其相关炎症信号通路的作用及机制。

良性前列腺增生(BPH)与组织炎症密切相关。炎症与饮食的关联近年来引起学界的广泛关注。我们在本研究中发现了促炎饮食会通过TNF-⍺/NLRP3/IL-18这一关键通路诱导CD4+效应记忆T细胞、CD8+效应记忆T细胞、CD8+中央记忆T细胞浸润前列腺组织，从而促进BPH的发生发展。.本研究首先利用美国国家健康与营养调查的数据探索了膳食炎症指数与中老年男性下尿路症状的关系，发现过量的促炎饮食摄入与下尿路症状发生风险正相关。随后我们在本中心的BPH手术患者中开展饮食问卷调查，并检测了患者外周血的炎症指标（TNF-⍺、IL-1β、IL-6等），证实了促炎饮食摄入与BPH的关联，同时我们发现在两者的关联中TNF-⍺起中介效应。我们再采用转录组测序的方式对比了增生前列腺和正常前列腺组织标本，进行Hub关键基因筛选，用7种不同算法同时锁定了TNF-⍺这一关键基因。另外通过xCell免疫浸润算法发现了测序数据中BPH中显著增高的免疫细胞亚群为CD4+效应记忆T细胞、CD8+效应记忆T细胞和CD8+中央记忆T细胞。此外，我们还绘制了TNF-⍺相关差异基因的蛋白互作网络，发现TNF-⍺下游分子NLRP3、IL-18均升高，另外通过免疫组化染色发现前列腺组织中NLRP3、IL-18主要表达在前列腺上皮细胞。接下来，我们利用高脂饮食诱导的BPH大鼠模型开展实验，发现高脂饮食使得大鼠前列腺指数显著增高、外周血TNF-⍺和IL-18显著升高、前列腺组织中TNF-⍺/NLRP3/IL-18通路分子的表达均升高、前列腺T细胞浸润显著增加；而如果在高脂饮食喂养的同时予NLRP3炎症小体抑制剂MCC950治疗可以显著改善大鼠的前列腺增生和前列腺T细胞浸润。随后，我们在细胞层面开展体外实验，验证了前列腺上皮细胞受TNF-⍺刺激后NLRP3/IL-18通路被激活，并且通过磁珠分选BPH患者外周血中的T细胞亚群（CD4+效应记忆T细胞、CD8+记忆T细胞）后进行实验，发现IL-18可以增加上述T细胞亚群的细胞迁移能力。本研究发现了饮食与前列腺增生的关联以及其中发挥关键作用的通路和T细胞亚群，对前列腺增生的预防和治疗提供了新的思路。