Impaired Sonic Hedgehog Responsiveness of Induced Pluripotent Stem Cell-Derived Floor Plate Cells Carrying the LRRK2-I1371V Mutation Contributes to the Ontogenic Origin of Lower Dopaminergic Neuron Yield.

Lower population of dopaminergic (DA) neurons is known to increase susceptibility to Parkinson's disease (PD), and our earlier study showed a lower yield of DA neurons in Leucine-Rich Repeat Kinase Isoleucine 1371 Valine (LRRK2-I1371V) mutation-carrying PD patient-derived induced Pluripotent Stem Cells (iPSCs). Although the role of Sonic Hedgehog (SHH) in DA neurogenesis of floor plate cells (FPCs) is known, the effect of LRRK2 mutations on SHH responsiveness of FPCs impacting DA neuronal yield has not been studied. We investigated SHH responsiveness of FPCs derived from LRRK2-I1371V PD patient iPSCs with regard to the expression of SHH receptors Patched1 (Ptch1) and Smoothened (Smo), in conjunction with nuclear Gli1 (glioma-associated oncogene 1) expression, intracellular Ca rise, and cytosolic cyclic adenosine monophosphate (cAMP) levels upon SHH induction.

Astrocytes Differentiated from LRRK2-I1371V Parkinson's-Disease-Induced Pluripotent Stem Cells Exhibit Similar Yield but Cell-Intrinsic Dysfunction in Glutamate Uptake and Metabolism, ATP Generation, and Nrf2-Mediated Glutathione Machinery.

Owing to the presence of multiple enzymatic domains, LRRK2 has been associated with a diverse set of cellular functions and signaling pathways. It also has several pathological mutant-variants, and their incidences show ethnicity biases and drug-response differences with expression in dopaminergic-neurons and astrocytes. Here, we aimed to assess the cell-intrinsic effect of the LRRK2-I1371V mutant variant, prevalent in East Asian populations, on astrocyte yield and biology, involving Nrf2-mediated glutathione machinery, glutamate uptake and metabolism, and ATP generation in astrocytes derived from LRRK2-I1371V PD patient iPSCs and independently confirmed in LRRK2-I1371V-overexpressed U87 cells.

Dopaminergic Neurons Differentiated from LRRK2 I1371V-Induced Pluripotent Stem Cells Display a Lower Yield, α-Synuclein Pathology, and Functional Impairment.

Being a large multidomain protein, LRRK2 has several confirmed pathological mutant variants for PD, and the incidence of these variants shows ethnicity biases. I1371V, a mutation in the GTPase domain, has been reported in East-Asian populations, but there are no studies reported on dopaminergic (DA) neurons differentiated from this variant. The aim here was to assess the yield, function, and α-synuclein pathology of DA neurons differentiated from LRRK2 I1371V iPSCs.

Reduction of phosphorylated α-synuclein through downregulation of casein kinase 2α alleviates dopaminergic-neuronal function.

Among the post-translational modifications of α-synuclein, phosphorylation has been reported to modulate the protein's nuclear localization, gene-expression and cytotoxicity. However, its effect on the functional performance of dopaminergic-neurons is not known. We aimed to evaluate the effect of siRNA-silencing of casein kinase (CK)2α in SH-SY5Y-cells overexpressing A53T α-synuclein, in alleviating phosphorylated α-synuclein serine129 (pSyn-129)-induced changes in intracellular Ca ([Ca]) response to physiological stimuli and vesicular-dopamine release.

Mitochondrial Superoxide Dismutase Specifies Early Neural Commitment by Modulating Mitochondrial Dynamics.

Studies revealing molecular mechanisms underlying neural specification have majorly focused on the role played by different transcription factors, but less on non-nuclear components. Earlier, we reported mitochondrial superoxide dismutase (SOD2) to be essential for self-renewal and pluripotency of mouse embryonic stem cells (mESCs). In the present study, we found SOD2 to be specifically required for neural lineage, but not the meso- or endoderm specification.

Generation of induced pluripotent stem cells (NIMHi001-A) from a Parkinson's disease patient of East Indian ethnicity carrying LRRK2 I1371V variant.

Mutations in the Leucine Repeat Rich Kinase-2 (LRRK2) gene have been reported in familial Parkinson's disease (PD) cases. We have generated induced pluripotent stem cells (iPSCs) using Sendai-virus reprogramming-method from peripheral blood mononuclear cells of PD-patient of East-Indian ethnicity carrying the I1371V mutation in LRRK2 gene. PD diagnosis was performed using Unified Parkinson's Disease rating scale (UPDRS) score and confirmed by [F]fluoro-l-dopa [F-DOPA] positron emission tomography (F-DOPA PET).