Neurobiology Research Center, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, No. 66, Gongchang Road, Guangming District, Shenzhen, 518107, Guangdong, People's Republic of China.
Department of Anatomy and Neurobiology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzho, 510080, Guangdong, People's Republic of China.
Cell Mol Life Sci. 2022 Jan 10;79(1):64. doi: 10.1007/s00018-021-04115-y.
Nicotinic acetylcholine receptors (nAChRs) are widespread throughout the central nervous system. Signaling through nAChRs contributes to numerous higher-order functions, including memory and cognition, as well as abnormalities such as nicotine addiction and neurodegenerative disorders. Although recent studies indicate that the PDZ-containing proteins comprising PSD-95 family co-localize with nicotinic acetylcholine receptors and mediate downstream signaling in the neurons, the mechanisms by which α7nAChRs are regulated remain unclear. Here, we show that the PDZ-LIM domain family protein PDLIM5 binds to α7nAChRs and plays a role in nicotine-induced α7nAChRs upregulation and surface expression. We find that chronic exposure to 1 μM nicotine upregulated α7, β2-contained nAChRs and PDLIM5 in cultured hippocampal neurons, and the upregulation of α7nAChRs and PDLIM5 is increased more on the cell membrane than the cytoplasm. Interestingly, in primary hippocampal neurons, α7nAChRs and β2nAChRs display distinct patterns of expression, with α7nAChRs colocalized more with PDLIM5. Furthermore, PDLIM5 interacts with α7nAChRs, but not β2nAChRs in native brain neurons. Knocking down of PDLIM5 in SH-SY5Y abolishes nicotine-induced upregulation of α7nAChRs. In primary hippocampal neurons, using shRNA against PDLIM5 decreased both surface clustering of α7nAChRs and α7nAChRs-mediated currents. Proteomics analysis and isothermal titration calorimetry (ITC) results show that PDLIM5 interacts with α7nAChRs through the PDZ domain, and the interaction between PDLIM5 and α7nAChRs can be promoted by nicotine. Collectively, our data suggest a novel cellular role of PDLIM5 in the regulation of α7nAChRs, which may be relevant to plastic changes in the nervous system.
烟碱型乙酰胆碱受体（nAChRs）广泛存在于中枢神经系统中。nAChRs 的信号转导参与了许多高级功能，包括记忆和认知，以及尼古丁成瘾和神经退行性疾病等异常。尽管最近的研究表明，包含 PDZ 结构域的 PSD-95 家族蛋白与烟碱型乙酰胆碱受体共定位，并在神经元中介导下游信号转导，但α7nAChRs 的调节机制尚不清楚。在这里，我们表明 PDZ-LIM 结构域家族蛋白 PDLIM5 与α7nAChRs 结合，并在尼古丁诱导的α7nAChRs 上调和表面表达中发挥作用。我们发现，在培养的海马神经元中，1 μM 尼古丁慢性暴露会上调α7、β2 包含的 nAChRs 和 PDLIM5，并且α7nAChRs 和 PDLIM5 的上调在细胞膜上比细胞质中更多。有趣的是，在原代海马神经元中，α7nAChRs 和 β2nAChRs 的表达模式不同，α7nAChRs 与 PDLIM5 的共定位更多。此外，PDLIM5 在原代脑神经元中与α7nAChRs 相互作用，但与β2nAChRs 不相互作用。在 SH-SY5Y 细胞中敲低 PDLIM5 可消除尼古丁诱导的α7nAChRs 上调。在原代海马神经元中，使用针对 PDLIM5 的 shRNA 减少了α7nAChRs 的表面聚类和α7nAChRs 介导的电流。蛋白质组学分析和等温热力学滴定（ITC）结果表明，PDLIM5 通过 PDZ 结构域与α7nAChRs 相互作用，尼古丁可以促进 PDLIM5 与α7nAChRs 之间的相互作用。总的来说，我们的数据表明 PDLIM5 在调节α7nAChRs 方面具有新的细胞作用，这可能与神经系统的可塑性变化有关。
