LRRK2调节纹状体神经元多巴胺受体1含量及机制

Study on LRRK2 Regulated Expression of Dopamine Receptor 1 in Striatal Neurons and Its Mechanism

目的探讨帕金森病相关蛋白LRRK2对纹状体神经元中多巴胺受体D1R含量的影响以及相关机制。方法利用组织免疫荧光染色法检测LRRK2基因敲除小鼠、LRRK2 G2019S突变基因敲入小鼠和R1441C突变基因敲入小鼠纹状体神经元中D1R含量的改变。并利用cathepsin D免疫荧光标记溶酶体,检测LRRK2基因敲除、LRRK2 G2019S和R1441C突变对蛋白降解的影响。结果 LRRK2基因敲除小鼠、LRRK2 G2019S和R1441C基因敲入小鼠纹状体中D1R荧光强度均显著下降。LRRK2基因敲除小鼠、LRRK2 G2019S和R1441C基因敲入小鼠纹状体神经元中溶酶体数目均显著增加,LRRK2 G2019S和R1441C基因敲入小鼠纹状体神经元中溶酶体大小增加,LRRK2基因敲除小鼠、LRRK2 G2019S和R1441C基因敲入小鼠纹状体神经元内与溶酶体共定位的D1R显著增加。结论 LRRK2基因敲除、LRRK2 G2019S和R1441C突变导致纹状体D1R的含量下降。LRRK2基因敲除、LRRK2 G2019S和R1441C突变提高小鼠纹状体神经元蛋白降解水平,D1R降解加强,从而使得纹状体神经元内D1R含量下降。

Objective To investigate the regulation of Parkinson′s disease related protein LRRK2 on the expression level of dopamine receptor 1(D1R)in striatal neurons and the related mechanism.Methods Histology immunofluorescence staining was applied to detect the D1R expression levelin striatal neurons of LRRK2 knockout mice,LRRK2 G2019S knockin mice and R1441Cknockin mice.Lysosome marker cathepsin D was stained to detect the effect of LRRK2 knockout,LRRK2 G2019S and R1441C mutation on protein degradation.Results The fluorescence intensity of D1R in the striatum of LRRK2 knockout mice,LRRK2 G2019S and R1441Cknockin mice decreased significantly.The number of lysosomes in striatal neurons of LRRK2 knockout mice,LRRK2 G2019S and R1441Cknockin mice were significantly increased;and the size of lysosomes in LRRK2 G2019S and R1441Cknockin mice was also significantly increased.Meanwhile,colocalization of D1R and lysosomes was significantly increased.Conclusion LRRK2 knockout,LRRK2 G2019S and R1441C mutation resulted in the decrease of D1R in striatum of mice.LRRK2 knockout,LRRK2 G2019S and R1441C mutation promoted the protein degradation,which led to the decrease of D1R in striatal neurons of mice.