Wang Kun, Sun Chenhan, Zhuang Hongda, Jiang Xian-Cheng, Chen Yong
School of Life Sciences, Nanchang University, 999 Xuefu Ave., Honggutan District, Nanchang, 330031, Jiangxi, People's Republic of China.
Institute for Advanced Study, Nanchang University, Nanchang, 330031, Jiangxi, China.
Cell Mol Biol Lett. 2025 Mar 18;30(1):32. doi: 10.1186/s11658-025-00715-9.
The receptor recognition and interaction of plasma lipoproteins (e.g., native low-density lipoproteins (LDL)/oxidized low-density lipoproteins (oxLDL), as well as the influence of microenvironmental/lysosomal acidification, play critical roles in lipoprotein metabolism and diseases (e.g., atherosclerosis) but have been less investigated. Here, the recognition/interaction of LDL or oxLDL with LDL receptor (LDLR) or CD36 (a scavenger receptor) or with living cells at various pHs was evaluated mainly via atomic force microscopy (AFM). To improve force measurement accuracy, a novel, micro-droplet-based method for AFM probe functionalization was developed. We found that solution acidification significantly reduced the LDL-LDLR binding at pH ≤ 6.4, whereas the oxLDL-CD36 binding had no significant change until pH ≤ 4.4. Compared with a traditional immersion method, our micro-droplet method for AFM probe functionalization produced more accurate interaction forces, and revealed that acidification significantly reduced the LDL-LDLR/cell interaction forces, instead of the oxLDL-CD36/cell-specific interaction forces and nonspecific interaction forces. The data imply that the LDL-LDLR/cell recognition and interaction are susceptible to acidification, whereas the oxLDL-CD36/cell recognition and interaction are tolerant of acidification. The results may provide important novel information and biomechanical/pathological implications for understanding lipoprotein metabolism and atherosclerosis.
血浆脂蛋白的受体识别与相互作用(例如天然低密度脂蛋白(LDL)/氧化低密度脂蛋白(oxLDL)),以及微环境/溶酶体酸化的影响,在脂蛋白代谢和疾病(如动脉粥样硬化)中起着关键作用,但此前研究较少。在此,主要通过原子力显微镜(AFM)评估了LDL或oxLDL与低密度脂蛋白受体(LDLR)或CD36(一种清道夫受体)或与处于不同pH值的活细胞之间的识别/相互作用。为提高力测量的准确性,开发了一种基于微滴的新型AFM探针功能化方法。我们发现,在pH≤6.4时,溶液酸化显著降低了LDL-LDLR的结合,而oxLDL-CD36的结合在pH≤4.4时才出现显著变化。与传统的浸入法相比,我们基于微滴的AFM探针功能化方法产生了更准确的相互作用力,并揭示酸化显著降低了LDL-LDLR/细胞相互作用力,而非oxLDL-CD36/细胞特异性相互作用力和非特异性相互作用力。这些数据表明,LDL-LDLR/细胞识别与相互作用易受酸化影响,而oxLDL-CD36/细胞识别与相互作用则对酸化具有耐受性。这些结果可能为理解脂蛋白代谢和动脉粥样硬化提供重要的新信息以及生物力学/病理学意义。