Shiratsuchi A, Umeda M, Ohba Y, Nakanishi Y
Graduate School of Natural Science and Technology, Kanazawa University, Takara-machi, Kanazawa, Ishikawa 920, Japan.
J Biol Chem. 1997 Jan 24;272(4):2354-8. doi: 10.1074/jbc.272.4.2354.
In a primary co-culture of spermatogenic and Sertoli cells of the rat, many spermatogenic cells die by apoptosis and are subsequently engulfed by Sertoli cells. We investigated the mechanism of this phagocytosis reaction. Testicular cells from 20-day-old rats were cultured, and spermatogenic cells and Sertoli cells were separated. When the recovered spermatogenic cells were maintained without Sertoli cells, the viability of the cells decreased and they became more susceptible to phagocytosis by Sertoli cells. Phagocytosis was severely impaired when liposomes containing acidic phospholipids, such as phosphatidylserine, phosphatidylinositol, and cardiolipin, were included in the reaction, whereas those consisting of neutral phospholipids showed little effect. Such anionic liposomes were more efficiently engulfed by Sertoli cells than were the other neutral liposomes. Also, the number of spermatogenic cells that exposed phosphatidylserine to the surface increased when cells were maintained in single culture. The results indicate that upon induction of spermatogenic cell apoptosis, phosphatidylserine and probably other acidic phospholipids, which are normally localized in the inner leaflet of the plasma membrane, translocate to the outer leaflet and serve as a signal for phagocytosis by Sertoli cells.
在大鼠生精细胞和支持细胞的原代共培养中，许多生精细胞通过凋亡死亡，随后被支持细胞吞噬。我们研究了这种吞噬反应的机制。培养20日龄大鼠的睾丸细胞，并分离出生精细胞和支持细胞。当回收的生精细胞在没有支持细胞的情况下培养时，细胞活力下降，并且它们变得更容易被支持细胞吞噬。当反应中包含含有酸性磷脂（如磷脂酰丝氨酸、磷脂酰肌醇和心磷脂）的脂质体时，吞噬作用严重受损，而由中性磷脂组成的脂质体几乎没有影响。与其他中性脂质体相比，这种阴离子脂质体更有效地被支持细胞吞噬。此外，当细胞在单培养中培养时，表面暴露磷脂酰丝氨酸的生精细胞数量增加。结果表明，在生精细胞凋亡诱导后，通常位于质膜内小叶的磷脂酰丝氨酸以及可能的其他酸性磷脂会转移到外小叶，并作为支持细胞吞噬作用的信号。
