Blood-testis barrier (BTB) damage promotes spermatogenesis dysfunction, which is a critical cause of male infertility. Dyslipidemia has been correlated with male infertility, but the major hazardous lipid and the underlying mechanism remains unclear. In this study, we firstly discovered an elevation of palmitic acid (PA) and a decrease of inhibin B in patients with severe dyszoospermia, which leaded us to explore the effects of PA on Sertoli cells. We observed a damage of BTB by PA. PA penetration to endoplasmic reticulum (ER) and its damage to ER structures were exhibited by microimaging and dynamic observation, and consequent ER stress was proved to mediate PA-induced Sertoli cell barrier disruption. Remarkably, we demonstrated a critical role of aberrant protein palmitoylation in PA-induced Sertoli cell barrier dysfunction. An ER protein, Calnexin, was screened out and was demonstrated to participate in this process, and suppression of its palmitoylation showed an ameliorating effect. We also found that ω-3 poly-unsaturated fatty acids down-regulated Calnexin palmitoylation, and alleviated BTB dysfunction. Our results indicate that dysregulated palmitoylation induced by PA plays a pivotal role in BTB disruption and subsequent spermatogenesis dysfunction, suggesting that protein palmitoylation might be therapeutically targetable in male infertility.

血睾丸屏障 (BTB) 损伤会促进精子发生功能障碍，这是导致男性不育的关键原因。血脂异常与男性不育有关，但主要的危险脂质及其潜在机制仍不清楚。在本研究中，我们首次发现重度精子症患者的棕榈酸（PA）升高和抑制素 B 降低，这促使我们探索 PA 对支持细胞的影响。我们观察到 PA 对 BTB 的损害。通过显微成像和动态观察显示了 PA 对内质网 (ER) 的渗透及其对 ER 结构的损伤，并证明了随后的 ER 应激介导了 PA 诱导的支持细胞屏障破坏。值得注意的是，我们证明了异常蛋白棕榈酰化在 PA 诱导的支持细胞屏障功能障碍中的关键作用。ER蛋白，Calnexin 被筛选出来并被证明参与了这一过程，并且抑制其棕榈酰化表现出改善作用。我们还发现 ω-3 多不饱和脂肪酸下调 Calnexin 棕榈酰化，并减轻 BTB 功能障碍。我们的研究结果表明，PA 诱导的失调棕榈酰化在 BTB 破坏和随后的精子发生功能障碍中起关键作用，这表明蛋白质棕榈酰化可能在男性不育症中具有治疗作用。