LRRK2调节纹状体神经元多巴胺受体2含量及机制研究

Study of LRRK2 regulated expression of dopamine receptor 2 in striatal neurons and its mechanism

目的探讨LRRK2的表达或功能异常对纹状体神经元多巴胺受体D2R含量的影响,以及LRRK2调节纹状体神经元多巴胺受体D2R含量的机制。方法利用组织免疫荧光染色法检测LRRK2基因敲除小鼠、LRRK2 G2019S基因敲入小鼠和R1441C基因敲入小鼠纹状体神经元中D2R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D2R荧光强度均显著下降;LRRK2 G2019S和R1441C基因敲入小鼠纹状体神经元中溶酶体数目和大小均显著增加,与Cathepsin D共定位的D2R显著增加。而LRRK2基因敲除小鼠纹状体神经元中溶酶体数目和大小与野生型相比差异无统计学意义。结论LRRK2基因敲除、LRRK2 G2019S和R1441C突变导致纹状体D2R的含量下降;LRRK2G2019S和R1441C突变提高小鼠纹状体神经元降解,促使D2R降解加强,从而使得纹状体神经元内D2R含量下降。

Objective To explore the regulation of Parkinson’s disease(PD)related protein LRRK2 on the expression level of dopamine receptor 2(D2 R)in striatal neurons and its related mechanism.Methods Histology immunofluorescence staining was applied to detect the changes of D2 R expression level in striatal neurons of LRRK2 knockout mice,LRRK2 G2019 S knockin mice and R1441 C knockin mice;lysosome marker Cathepsin D was stained to detect the effect of LRRK2 knockout,LRRK2 G2019 S and R1441 C mutation on protein degradation.Results The fluorescence intensity of D2 R in the striatum of LRRK2 knockout mice,LRRK2 G2019 S and R1441 C knockin mice decreased significantly.The number and size of lysosomes in striatal neurons of LRRK2 G2019 S and R1441 C knockin mice were significantly increased.Colocalization of D2 R and lysosomes was also significantly increased in LRRK2 G2019 S and R1441 C knockin mice.However,the number and size of lysosomes in striatal neurons of LRRK2 knockout mice were not significantly different from those of wild type mice.Conclusion LRRK2 knockout,LRRK2 G2019 S and R1441 C mutation resulted in the decrease of D2 R in striatum of mice,LRRK2 G2019 S and R1441 C mutation promoted the protein degradation in mice striatum neurons,which led to the decrease of D2 R in striatal neurons.