CHCHD2 Thr61Ile mutation impairs F1F0-ATPase assembly in in vitro and in vivo models of Parkinson's disease

Mitochondrial dysfunction is a significant pathological alte ration that occurs in Parkinson's disease(PD),and the Thr61lle(T61I)mutation in coiled-coil helix coiled-coil helix domain containing 2(CHCHD2),a crucial mitochondrial protein,has been reported to cause Parkinson's disease.FIFO-ATPase participates in the synthesis of cellular adenosine triphosphate(ATP)and plays a central role in mitochondrial energy metabolism.However,the specific roles of wild-type(WT)CHCHD2 and T611-mutant CHCHD2 in regulating F1FO-ATPase activity in Parkinson's disease,as well as whether CHCHD2 or CHCHD2 T61I affects mitochondrial function through regulating F1FO-ATPase activity,remain unclea r.Therefore,in this study,we expressed WT CHCHD2 and T61l-mutant CHCHD2 in an MPP^(+)-induced SH-SY5Y cell model of PD.We found that CHCHD2 protected mitochondria from developing MPP^(+)-induced dysfunction.Under normal conditions,ove rexpression of WT CHCHD2 promoted F1FO-ATPase assembly,while T61I-mutant CHCHD2 appeared to have lost the ability to regulate F1FO-ATPase assembly.In addition,mass spectrometry and immunoprecipitation showed that there was an interaction between CHCHD2 and F1FO-ATPase.Three weeks after transfection with AAV-CHCHD2 T61I,we intraperitoneally injected 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine into mice to establish an animal model of chronic Parkinson's disease and found that exogenous expression of the mutant protein worsened the behavioral deficits and dopaminergic neurodegeneration seen in this model.These findings suggest that WT CHCHD2 can alleviate mitochondrial dysfunction in PD by maintaining F1F0-ATPase structure and function.

Peripheral Lymphocyte Subsets as a Marker of Parkinson's Disease in a Chinese Population

In this study, we conducted a clinical analysis of lymphocyte subtypes in 268 patients with Parkinson's disease(PD) to assess their clinical impact as a potential marker of advanced PD in Chinese patients. The participants comprised 268 sporadic PD patients and 268 healthy controls. The numbers of natural killer(NK) cells and CD3+, CD3+CD4+, CD3+CD8+, and CD19+ lymphocytes from peripheral blood were determined by immunostaining and flow cytometric analysis and the percentages of these CD+ T cells were calculated. The ratio of regulatory T(Treg)/helper T 17(Th17) lymphocytes from 64 PD patients and 46 controls was determined by flow cytometric analysis.The results showed that the percentage of NK cells was higher in advanced PD patients than in controls(22.92% ±10.08% versus 19.76% ± 10.09%, P = 0.006), while CD3+ T cells are decreased(62.93% ± 9.27% versus65.75% ± 9.13%, P = 0.005). The percentage of CD19+B cells in male patients was lower(P = 0.021) than in female patients, whereas NK cells were increased(P \ 0.0001). The scores on the Unified Parkinson's Disease Rating Scale(UPDRS) and the Non-Motor Symptoms Scale in late-onset PD patients were significantly higher than those in earlyonset patients(P = 0.024 and P = 0.007, respectively). The percentage of CD19+ B cells in patients with UPDRS scores[24 was lower than in those with scores \24(10.17% ±4.19% versus 12.22% ± 5.39%, P = 0.009). In addition, the Treg/Th17 ratio in female patients was higher than that in female controls(13.88 ± 6.32 versus 9.94 ± 4.06, P =0.042). These results suggest that the percentages of NK cells,CD3+ T cells, and CD19+ B cells along with the Treg/Th17 ratio in peripheral blood may be used to predict the risk of PD in Chinese individuals and provide fresh avenues for novel diagnostic biomarkers and therapeutic designs.

CHCHD2 maintains mitochondrial contact site and cristae organizing system stability and protects against mitochondrial dysfunction in an experimental model of Parkinson’s disease

Background:Parkinson’s disease(PD)is the second most common neurodegenerative disease after Alzheimer’s dementia.Mitochondrial dysfunction is involved in the pathology of PD.Coiled-coil-helix-coiled-coil-helix domain-containing 2(CHCHD2)was identified as associated with autosomal dominant PD.However,the mechanism of CHCHD2 in PD remains unclear.Methods:Short hairpin RNA(ShRNA)-mediated CHCHD2 knockdown or lentivirus-mediated CHCHD2 overexpression was performed to investigate the impact of CHCHD2 on mitochondrial morphology and function in neuronal tumor cell lines represented with human neuroblastoma(SHSY5Y)and HeLa cells.Blue-native polyacrylamide gel electrophoresis(PAGE)and two-dimensional sodium dodecyl sulfate-PAGE analysis were used to illustrate the role of CHCHD2 in mitochondrial contact site and cristae organizing system(MICOS).Co-immunoprecipitation and immunoblotting were used to address the interaction between CHCHD2 and Mic10.Serotype injection of adeno-associated vector-mediated CHCHD2 and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)administration were used to examine the influence of CHCHD2 in vivo.Results:We found that the overexpression of CHCHD2 can protect against methyl-4-phenylpyridinium(MPP+)-induced mitochondrial dysfunction and inhibit the loss of dopaminergic neurons in the MPTP-induced mouse model.Furthermore,we identified that CHCHD2 interacted with Mic10,and overexpression of CHCHD2 can protect against MPP+-induced MICOS impairment,while knockdown of CHCHD2 impaired the stability of MICOS.Conclusion:This study indicated that CHCHD2 could interact with Mic10 and maintain the stability of the MICOS complex,which contributes to protecting mitochondrial function in PD.