远端遗传性运动神经病(dHMN)是一种进行性神经系统疾病,其特征是远端肢体肌肉无力和肌萎缩。西格玛1受体(σ1R),SIGMAR1的基因产物,已经报道突变诱导dHMN,但其机制尚不清楚。本研究旨在探讨σ1R中C238T和31_50del突变对神经元SH-SY5Y细胞功能的影响。过表达σ1R的SH-SY5Y细胞,通过pEGFPN1载体构建了C238T突变体σ1R(σ1RC238T)或31_50del突变体σ1R(σ1R31_50del)。我们使用Westernblot(WB)和免疫荧光(IF)染色检测σ1R和绿色荧光蛋白(GFP)的表达。然后,我们评估了σ1R突变对细胞凋亡的影响,自噬,内质网应激,并参与SH-SY5Y细胞的未折叠蛋白反应(UPR)途径。我们发现σ1RC238T和σ1R31_50del下调σ1R并促进SH-SY5Y细胞凋亡。σ1RC238T和σ1R31_50del增加p-PERK,p-eIF2α,p-JNK,BIP,ATF4,CHOP,ATF6、XBP1、Caspase3、Caspase12表达与Ca2+浓度,而SH-SY5Y细胞中ATP含量降低。此外,LC3B的表达式,Lamp1,ATG7,Beclin-1和AMPK和ULK1的磷酸化增加,而σ1R的C238T或31_50del突变后p62水平降低。此外,AMPK敲低消除了SH-SY5Y细胞中σ1RC238T或σ1R31_50del介导的凋亡。我们的结果表明,σ1R中的C238T或31_50del突变通过AMPK/ULK1途径促进dHMN中的运动神经元凋亡。这项研究揭示了更好地理解dHMN中σ1RC238T和σ1R31-50del介导的神经元病理机制。
Distal hereditary motor neuropathy (
dHMN) is a progressive neurological disease characterized by distal limb muscle weakness and amyotrophy. Sigma 1 receptor (σ1R), a gene product of SIGMAR1, mutations have been reported to induce
dHMN, but its mechanism remains unknown. This study aims to explore the effect of C238T and 31_50del mutations in σ1R on neuronal SH-SY5Y cell functions. The SH-SY5Y cells that overexpressed σ1R, C238T mutant σ1R (σ1RC238T) or 31_50del mutant σ1R (σ1R31_50del) were constructed by pEGFPN1 vectors. We used Western blot (WB) and immunofluorescence (IF) staining to detect the expression of σ1R and green fluorescent proteins (GFP). Then, we evaluated the impact of σ1R mutation on apoptosis, autophagy, endoplasmic reticulum stress, and the involvement of the unfolded protein response (UPR) pathway in SH-SY5Y cells. We found that σ1RC238T and σ1R31_50del downregulated σ1R and promoted the apoptosis of SH-SY5Y cells. σ1RC238T and σ1R31_50del increased p-PERK, p-eIF2α, p-JNK, BIP, ATF4, CHOP, ATF6, XBP1, Caspase3, Caspase12 expressions and Ca2+ concentration, whereas decreased ATP content in SH-SY5Y cells. Besides, the expressions of LC3B, Lamp1, ATG7, Beclin-1 and phosphorylation of AMPK and ULK1 were increased, while the p62 level decreased after C238T or 31_50del mutation of σ1R. Additionally, AMPK knockdown abolished the apoptosis mediated by σ1RC238T or σ1R31_50del in SH-SY5Y cells. Our results indicated that C238T or 31_50del mutation in σ1R promoted motor neuron apoptosis through the AMPK/ULK1 pathway in
dHMN. This study shed light on a better understanding of the neurons pathological mechanisms mediated by σ1R C238T and σ1R 31-50del in
dHMN.