背景:肥胖是一种危害人类健康的世界性危机。在这种情况下,精子质量的下降源于精子浓度的降低,运动性和精子畸形增加。这些改变的潜在机制在很大程度上仍然未知。这项研究,确定小鼠精子中肥胖相关的蛋白质组表达模式是否与肥胖人类精子中的表达模式平行。
方法:通过饲喂高脂饮食(HFD)建立肥胖小鼠模型。组织学分析确定了睾丸形态,计算机辅助精液分析仪(CASA)评估了精子参数。使用无标记定量LC-MS/MS系统进行蛋白质组分析。蛋白质印迹,免疫组织化学和免疫荧光分析表征了睾丸中的蛋白质表达水平和定位,精子和临床样本。
结果:HFD诱导的肝脂肪变性的体重增加。精子活力下降伴随精子畸形发育。差异蛋白质组学分析鉴定了减少的细胞骨架蛋白,中心体和纺锤体极相关蛋白1(CSP1)和Centrin1(CETN1),肥胖小鼠的精子。在正常体重的小鼠中,CSP1和CETN1均位于精母细胞和精子细胞中。它们的表达在精子细胞中与manchette结构的微管轨道平行的顶体后区域中明显,影响精子细胞头部的形状和形态维持。此外,CSP1位于成熟精子的头-尾耦合装置中,而CETN1的表达被限定在精子头部的顶体后区域。重要的是,与体重正常的男性相比,超重和肥胖男性的精子CSP1和CETN1丰度均降低。
结论:这些发现表明,CETN1和CSP1的区域表达和定位与精子生成和精子形态维持密切相关。肥胖与小鼠和相关临床样品中CETN1和CSP1丰度的下降以及精子形态的损害有关。小鼠和人类中改变的蛋白质表达之间的这种平行性表明,这些作用可能导致精子质量差,包括畸形增加。
BACKGROUND: Obesity is a worldwide crisis impairing human health. In this condition, declines in sperm quality stem from reductions in sperm concentration, motility and increase in sperm deformity. The mechanism underlying these alterations remains largely unknown. This study, determined if obesity-associated proteomic expression patterns in mice sperm parallel those in spermatozoa obtained from obese humans.
METHODS: An obese mouse model was established via feeding a high-fat diet (HFD). Histological analysis identified testicular morphology and a computer assisted semen analyzer (CASA) evaluated sperm parameters. Proteome analysis was performed using a label-free quantitative LC-MS/MS system. Western blot, immunohistochemical and immunofluorescent analyses characterized protein expression levels and localization in testis, sperm and clinical samples.
RESULTS: Bodyweight gains on the HFD induced hepatic steatosis. Declines in sperm motility accompanied sperm deformity development. Differential proteomic analysis identified reduced cytoskeletal proteins, centrosome and spindle pole associated protein 1 (CSPP1) and Centrin 1 (CETN1), in sperm from obese mice. In normal weight mice, both CSPP1 and CETN1 were localized in the spermatocytes and spermatids. Their expression was appreciable in the post-acrosomal region parallel to the microtubule tracks of the manchette structure in spermatids, which affects spermatid head shaping and morphological maintenance. Moreover, CSPP1 was localized in the head-tail coupling apparatus of the mature sperm, while CETN1 expression was delimited to the post-acrosomal region within the sperm head. Importantly, sperm CSPP1 and CETN1 abundance in both the overweight and obese males decreased in comparison with that in normal weight men.
CONCLUSIONS: These findings show that regionally distinct expression and localization of CETN1 and CSPP1 is strongly related to spermiogenesis and sperm morphology maintaining. Obesity is associated with declines in the CETN1 and CSPP1 abundance and compromise of both sperm morphology in mice and relevant clinical samples. This parallelism between altered protein expression in mice and humans suggests that these effects may contribute to poor sperm quality including increased deformity.