Here, we investigated the role of the UPS and autophagy by applying the potassium ionophore Valinomycin in PINK1-deficient human fibroblasts and isogenic neuroblastoma cell lines generated by CRISPR/Cas9.
We used differentiated human dopaminergic neuroblastoma cell lines with stable PINK1 or DJ-1 knockdown to study live motility of mitochondria in neurites.
These abnormalities are associated with increased inflammation-induced NF-κB signaling in astrocytes, and cause enhanced death of neurons co-cultured with inflamed PINK1 <sup>-/-</sup> mixed glia and neuroblastoma cells exposed to conditioned medium from LPS/IFN-γ treated PINK1 <sup>-/-</sup> mixed glia.
The aim of the present study was to create a cellular model of PD using siRNA-mediated knock down of PINK1 in SH-SY5Y neuroblastoma cells The possible protective effects of curcumin, known for its many beneficial properties including antioxidant and anti-inflammatory effects, was tested on this model in the presence and absence of paraquat, an additional stressor.
Marked dysregulations of microbial defense factors Ifit3 and Rsad2 were consistently observed upon five analyses: (1) Pink1 <sup>-/-</sup> primary neurons in the first weeks after brain dissociation, (2) aged Pink1 <sup>-/-</sup> midbrain with transgenic A53T-alpha-synuclein overexpression, (3) human neuroblastoma cells with PINK1-knockdown and murine Pink1 <sup>-/-</sup> embryonal fibroblasts undergoing acute starvation, (4) triggering mitophagy in these cells with trifluoromethoxy carbonylcyanide phenylhydrazone (FCCP), and (5) subjecting them to pathogenic RNA-analogue poly(I:C).
In this study, we report that increased mitochondrial PINK1 levels observed in human neuroblastoma SH-SY5Y cells after carbonyl cyanide m-chlorophelyhydrazone (CCCP) treatment were due to de novo protein synthesis, and not just increased stabilization of full length PINK1 (FL-PINK1).
Here, we demonstrate that Miro1, an outer mitochondrial membrane (OMM) protein crucial for the regulation of mitochondrial trafficking and distribution, is a substrate of the PINK1/Parkin mitochondrial quality control system in human dopaminergic neuroblastoma cells.
We previously reported that stable neuroblastoma SH-SY5Y cell lines with reduced expression of endogenous PINK1 exhibit mitochondrial fragmentation, increased mitochondria-derived superoxide, induction of compensatory macroautophagy/mitophagy and a low level of ongoing cell death.
To investigate the cytoprotective physiological function of PINK1, we used primary fibroblasts from three patients homozygous for G309D-PINK1 as well as SHEP neuroblastoma cells stably overexpressing GFP-tagged wild type (wt) PINK1.
Here, we show that Parkin, PINK1, and DJ-1 formed a complex (termed PPD complex) to promote ubiquitination and degradation of Parkin substrates, including Parkin itself and Synphilin-1 in neuroblastoma cells and human brain lysates.