SLP-2 interacts with Parkin in mitochondria and prevents mitochondrial dysfunction in Parkin-deficient human iPSC-derived neurons andDrosophila

Abstract

Mutations in the Parkin gene (PARK2) have been linked to a recessive form of Parkinson's disease (PD) characterized by the loss of dopaminergic neurons in the substantia nigra. Deficiencies of mitochondrial respiratory chain complex I activity have been observed in the substantia nigra of PD patients, and loss of Parkin results in the reduction of complex I activity shown in various cell and animal models. Using co-immunoprecipitation and proximity ligation assays on endogenous proteins, we demonstrate that Parkin interacts with mitochondrial Stomatin-like protein 2 (SLP-2), which also binds the mitochondrial lipid cardiolipin and functions in the assembly of respiratory chain proteins. SH-SY5Y cells with a stable knockdown of Parkin or SLP-2, as well as induced pluripotent stem cell-derived neurons from Parkin mutation carriers, showed decreased complex I activity and altered mitochondrial network morphology. Importantly, induced expression of SLP-2 corrected for these mitochondrial alterations caused by reduced Parkin function in these cells. In-vivo Drosophila studies showed a genetic interaction of Parkin and SLP-2, and further, tissue-specific or global overexpression of SLP-2 transgenes rescued parkin mutant phenotypes, in particular loss of dopaminergic neurons, mitochondrial network structure, reduced ATP production, and flight and motor dysfunction. The physical and genetic interaction between Parkin and SLP-2 and the compensatory potential of SLP-2 suggest a functional epistatic relationship to Parkin and a protective role of SLP-2 in neurons. This finding places further emphasis on the significance of Parkin for the maintenance of mitochondrial function in neurons and provides a novel target for therapeutic strategies.

Induced pluripotent stem cell‐based modeling of mutant LRRK2‐associated Parkinson's disease

“…In summary, alterations in mitochondrial morphology were repeatedly shown not only for LRRK2 variants (Su & Qi, 2013) but also for mutants of SNCA trp/A53T PINK1, PRKN and OPA1 (Chung et al, 2016;Iannielli et al, 2018;Imaizumi et al, 2012;Little et al, 2018;Shaltouki et al, 2015;Zanon et al, 2017).…”

Parkin Interacts with Apoptosis-Inducing Factor and Interferes with Its Translocation to the Nucleus in Neuronal Cells

“…CCL-2) were cultured in Dulbecco’s modified Eagle’s Medium (DMEM, Sigma-Aldrich, Milan, Italy) supplemented with 10% fetal bovine serum and 1% penicillin-streptomycin (Thermo Fisher Scientific, Rodano, Italy). SH-SY5Y cells with a stable parkin knockdown or stably overexpressing parkin have been recently described [48]. SH-SY5Y cells were exposed to CCCP (10 µM, 3 h, Sigma-Aldrich) or STS (2 µM, 3 h, Sigma-Aldrich).…”

Patient-Derived Induced Pluripotent Stem Cell-Based Models in Parkinson’s Disease for Drug Identification

“…Studies in hiPSC-derived neurons from PD patients have revealed mitochondrial defects, including morphological and functional alterations (reviewed in [ 33 ]). In particular, fragmented mitochondria or mitochondria with abnormal morphology have been observed in hiPSC-derived neurons carrying LRRK2-G2019S [ 48 ], Parkin [ 49 , 50 , 51 , 52 , 53 ], PINK1 [ 51 , 54 ] or GBA mutations [ 55 ], but also SNCA-G209A or triplication [ 39 ]. Others have reported decreased mitochondrial content in patient neurons [ 56 , 57 , 58 ].…”

“…Others have reported decreased mitochondrial content in patient neurons [ 56 , 57 , 58 ]. Altered mitochondrial functionality has also been demonstrated [ 52 , 55 , 57 ], with decreased ATP production [ 43 , 48 ], reduced membrane potential [ 59 ] or dysfunctional mobility [ 60 ], affecting multiple cellular processes and altering the redox status of the neuron.…”