Schmaltz Lorraine, Barakat Elie, Fleurot Renaud, Uzbekov Rustem, Reynaud Karine, Laffont Ludivine, Tsikis Guillaume, Mérour Isabelle, Mermillod Pascal, Saint-Dizier Marie
INRAE, CNRS, University of Tours, Physiologie de la Reproduction et des comportements, Center INRAE Val-de-Loire, Nouzilly, France.
Laboratory of Cell Biology and Electron Microscopy, University of Tours, Tours, France.
Eur J Cell Biol. 2025 Mar;104(1):151471. doi: 10.1016/j.ejcb.2024.151471. Epub 2024 Dec 17.
After insemination, a subpopulation of sperm reaches the oviducts and binds to isthmic epithelial cells to form a "sperm reservoir". Our objective was to explore the role of annexin A5 (ANXA5), a protein that binds with high affinity to phosphatidylserine (PS), in the formation of the sperm reservoir in pigs. Phosphatidylserine was detected on the head of approximately 10 % of boar sperm at ejaculation. Porcine ANXA5 was immunodetected with a strong signal on luminal cilia in the isthmus and in derived isthmic epithelial spheroids (IES). Exogenous PS between 0.01 and 0.1 µg/mL and recombinant porcine ANXA5 (rpANXA5) above 0.1 µg/mL inhibited sperm binding to IES without reducing sperm motility. Pre-incubation of sperm, but not IES, with rpANXA5 inhibited sperm binding to IES. Under capacitating conditions, the proportion of live sperm with head PS exposure and the ability of sperm to bind to rpANXA5 and IES cilia increased within 30 min. Conversely, the acrosome reaction decreased the ability of sperm to bind rpANXA5 and prevented sperm binding to IES. In conclusion, sperm membrane remodelling during capacitation enhanced head PS exposure in motile sperm, resulting in increased interaction with ciliary ANXA5 on isthmic epithelial spheroids. These findings support a role for PS-ANXA5 interaction in the formation of the sperm reservoir in mammalian females.
授精后，一部分精子到达输卵管并与峡部上皮细胞结合形成“精子储存库”。我们的目的是探讨与磷脂酰丝氨酸（PS）具有高亲和力结合的膜联蛋白A5（ANXA5）在猪精子储存库形成中的作用。射精时，约10%的公猪精子头部可检测到磷脂酰丝氨酸。在峡部管腔纤毛和衍生的峡部上皮球体（IES）中，猪ANXA5免疫检测信号很强。0.01至0.1μg/mL的外源性PS和高于0.1μg/mL的重组猪ANXA5（rpANXA5）可抑制精子与IES的结合，但不降低精子活力。用rpANXA5预孵育精子而非IES可抑制精子与IES的结合。在获能条件下，头部暴露PS的活精子比例以及精子与rpANXA5和IES纤毛结合的能力在30分钟内增加。相反，顶体反应降低了精子与rpANXA5结合的能力，并阻止精子与IES结合。总之，获能过程中精子膜重塑增强了活动精子头部PS的暴露，导致与峡部上皮球体上纤毛ANXA5的相互作用增加。这些发现支持了PS-ANXA5相互作用在哺乳动物雌性精子储存库形成中的作用。
