Mechanism of impairment of testicular function by immune evasive mechanism of uropathogenic Escherichia coli (UPEC)

大肠杆菌感染是男性不育的主要因素。在支持细胞（SC）、小管周围细胞（PTC）和睾丸巨噬细胞（TM）中，感染尿路致病性大肠杆菌（UPEC）后，促炎NFKB途径在不同程度上被阻断，导致促炎细胞因子的分泌受到抑制。然而，受感染的细胞以活化T细胞核因子（NFAT）C2信号作为替代途径，导致抗炎Th2型反应。我们的目的是研究UPEC是否可以通过NFAT激活的组蛋白去乙酰化酶（HDAC1）染色质重塑来沉默NFKB调节的促炎基因转录。此外，我们还将研究upc对过氧化物酶体增殖物激活受体（PPAR）y抑制npkb介导的炎症反应的影响。建立的大鼠体内睾丸炎感染模型将用于连接我们的体外研究和人体活检调查。将监测细胞外和细胞内UPEC和突变体的持久性，以提供感染后uppec可能在活检标本中检测到的时间信息，以帮助指导诊断。最初的结果显示，在有炎症浸润的睾丸活检中存在细菌DNA，但无法揭示细菌的种类。新的自动化样品提取结合基于dhplc的分析和随后的微生物标记基因测序，可以区分尿路病原体和机会细菌。体内UPEC在体外观察到的免疫抑制特性将被验证，例如，通过检查从Thi到Th2免疫反应的假设转变。生殖道特异性抗菌肽（SPAG11和β -防御素的异构体）的作用将在体内感染模型中通过替代来检验。

E. coil based infection is an established major factor for male infertility. In Sertoli cells (SC), peritubular cells (PTC) and testicular macrophages (TM) the pro-inflammatory NFKB pathway is blocked downstream at different levels following infection with uropathogenic E. coli (UPEC) resulting in inhibited secretion of pro-inflammatory cytokines. Infected cells respond with nuclear factor of activated T cells (NFAT)C2 signaling as alternative pathway, however, leading to an anti-inflammatory Th2 type response. We aim to investigate if UPEC can silence NFKB regulated pro-inflammatory gene transcription by NFAT activated histone deacetylases (HDAC1) chromatin remodeling. Moreover, an influence of UPEC on peroxisome proliferator activated receptor (PPAR)y to repress NpKB-mediated inflammatory response will be investigated. An established rat in vivo orchitis infection model will be used to link our in vitro studies and the human biopsy investigations. Extra- and intracellular persistence of UPEC and mutants will be monitored to provide information up to what time post-infection UPEC may be detectable in biopsy specimens to help guiding diagnosis. Initial results show the presence of bacterial DNA in testis biopsies with inflammatory infiltrates, but could not reveal the species. New automated sample extraction combined with DHPLCbased profiling and subsequent sequencing of microbial marker genes allows discrimination of uropathogens and opportunistic bacteria. In vivo UPEC immunosuppressive properties seen in vitro shall be validated e.g. by examining the hypothesized shift from a Thi to a Th2 immune response. The role of reproductive tract specific antimicrobial peptides (isoforms of SPAG11 & beta-defensins) will be examined by substitution in the in vivo infection model.