Zhou Cong, Yang Mei-Jie, Shi Pu, Li Zhuo-Qing, Li Yong-Ren, Guo Yong-Jun, Zhang Tao, Song Hao
Center of Deep Sea Research, and CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China; CAS Engineering Laboratory for Marine Ranching, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
Center of Deep Sea Research, and CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China; CAS Engineering Laboratory for Marine Ranching, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Int J Biol Macromol. 2025 Apr;302:139483. doi: 10.1016/j.ijbiomac.2025.139483. Epub 2025 Jan 3.
Solute carrier family 23 (SLC23) mediates cellular uptake of ascorbic acid, a crucial antioxidant protecting organisms against oxidative stress. Despite advances in understanding SLC23 in mammals, its physiological roles in bivalves remain poorly understood. Notably, euryhaline bivalves exhibit a significant expansion and positive selection of SLC23, highlighting the need for deeper investigation. Here, we identified 25 MmSLC23 in the hard clam genome. These genes predominantly cluster on chromosomes 3 and 14, with tandem duplications driving their expansion. All MmSLC23 localize to the plasma membrane, containing 9-14 transmembrane domains. Syntenic conservation of SLC23 was limited across order Venerida, with most expanded members being lineage-specific paralogs. Transcriptome analysis and fluorescence in situ hybridization revealed that MmSLC23 exhibited divergent expression patterns under acute and chronic salinity stress. Notably, RNA interference of MmSLC23A2 led to a significant reduction in intracellular ascorbic acid levels. Under acute hypo-salinity stress, increased ROS levels and elevated apoptosis rate were observed in MmSLC23A2 knockdown clams, as assessed by flow cytometry and transmission electron microscopy. These findings underscore the crucial role of SLC23 in mitigating oxidative damage and preventing premature apoptosis under acute salinity stress, offering new insights into the molecular mechanisms underlying the remarkable salinity adaptability of euryhaline bivalves.
溶质载体家族23（SLC23）介导细胞对抗坏血酸的摄取，抗坏血酸是一种关键的抗氧化剂，可保护生物体免受氧化应激。尽管在了解哺乳动物中的SLC23方面取得了进展，但其在双壳贝类中的生理作用仍知之甚少。值得注意的是，广盐性双壳贝类的SLC23表现出显著的扩增和正选择，这凸显了深入研究的必要性。在这里，我们在硬壳蛤基因组中鉴定出25个MmSLC23。这些基因主要聚集在3号和14号染色体上，串联重复驱动了它们的扩增。所有MmSLC23都定位于质膜，含有9 - 14个跨膜结构域。SLC23在帘蛤目动物中的共线性保守性有限，大多数扩增成员是谱系特异性旁系同源物。转录组分析和荧光原位杂交表明，MmSLC23在急性和慢性盐度胁迫下表现出不同的表达模式。值得注意的是，MmSLC23A2的RNA干扰导致细胞内抗坏血酸水平显著降低。通过流式细胞术和透射电子显微镜评估，在急性低盐胁迫下，MmSLC23A2敲低的蛤中观察到活性氧水平升高和凋亡率升高。这些发现强调了SLC23在减轻氧化损伤和防止急性盐度胁迫下过早凋亡方面的关键作用，为广盐性双壳贝类显著的盐度适应性背后的分子机制提供了新的见解。
