Calcium homeostasis modulator 2 aggravates α-synuclein-induced neurotoxicity in Parkinson's disease by activating PARP-1 depended Parthanatos.

Background: Parkinson 's disease (PD) is a common neurodegenerative disease. Aggregates formed by α-synuclein (α-Syn) are the main pathological changes of PD. In this study, the effects of Calcium homeostasis modulator 2 (Calhm2) on α-syn-induced neurotoxicity in PD were evaluated.

Methods: Primary neurons were treated with α-Syn PFF to mimic the PD cellular model. Genes and proteins were evaluated utilizing RT-qPCR, Western blot and immunofluorescence, respectively. Cell damage was assessed using CCK-8 and LDH assay. Cellular oxidative stress was assessed via the detection of SOD, GSH and ROS level. Mitochondrial membrane potential, ATP level, AIF nuclear translocation and intracellular Ca2+ were determined for the assessment of Parthanatos. HE and immunofluorescence of TH and NeuN was detected pathological changes in vivo.

Results: α-Syn PFF administration greatly resulted in oxidative stress, calcium overload and PARP-1 dependent Parthanatos in primary neurons. Following α-Syn PFF administration, Calhm2 and Calhm3, key calcium homeostasis modulator (Calhm) proteins, were markedly elevated in neurons, while Calhm1 expression exhibited a little change. In addition, suppression of Calhm2 obviously mitigated α-Syn PFF-induced oxidative stress injury, calcium overload and PARP-1 dependent Parthanatos in vitro. Similarly, in vivo results demonstrated that α-Syn PFF treatment led to PARP-1-dependent Parthanatos and nerve injury, while these effects were reversed by Calhm2 knockdown.

Conclusion: Calhm2 repression lightened α-Syn aggregation-induced neurotoxicity and PARP-1-dependent Parthanatos in PD, providing a novel therapeutic target for PD treatment.