Project description:The common marmoset monkey (Callithrix jacchus; Cj) is an advantageous nonhuman primate species for modeling age-related disorders, including Parkinson's disease, due to their shorter life span compared to macaques. Cj-derived induced pluripotent stem cells (Cj-iPSCs) from somatic cells are needed for in vitro disease modeling and testing regenerative medicine approaches. Here we report the development of a novel Cj-iPSC line derived from adult marmoset fibroblasts. The Cj-iPSCs showed potent pluripotency properties, including the development of mesodermal lineages in tumors after injection to immunocompromised mice, as well as ectoderm and endoderm lineages after in vitro differentiation regimens, demonstrating differentiated derivatives of all three embryonic layers. In addition, expression of key pluripotency genes (ZFP42, PODXL, DNMT3B, C-MYC, LIN28, KLF4, NANOG, SOX2, and OCT4) was observed. We then tested the neural differentiation capacity and gene expression profiles of Cj-iPSCs and a marmoset embryonic stem cell line (Cj-ESC) after dual-SMAD inhibition. Exposure to CHIR99021 and sonic hedgehog (SHH) for 12 and 16 days, respectively, patterned the cells toward a ventralized midbrain dopaminergic phenotype, confirmed by expression of FOXA2, OTX2, EN-1, and tyrosine hydroxylase. These results demonstrate that common marmoset stem cells will be able to serve as a platform for investigating regenerative medicine approaches targeting the dopaminergic system.
Project description:Parkinson's disease (PD) is defined by the degeneration of nigral dopaminergic (DA) neurons and can be caused by monogenic mutations of genes such as parkin. The lack of phenotype in parkin knockout mice suggests that human nigral DA neurons have unique vulnerabilities. Here we generate induced pluripotent stem cells from normal subjects and PD patients with parkin mutations. We demonstrate that loss of parkin in human midbrain DA neurons greatly increases the transcription of monoamine oxidases and oxidative stress, significantly reduces DA uptake and increases spontaneous DA release. Lentiviral expression of parkin, but not its PD-linked mutant, rescues these phenotypes. The results suggest that parkin controls dopamine utilization in human midbrain DA neurons by enhancing the precision of DA neurotransmission and suppressing dopamine oxidation. Thus, the study provides novel targets and a physiologically relevant screening platform for disease-modifying therapies of PD.
Project description:Mutations in the PARK2 gene encoding parkin, an E3 ubiquitin ligase, are associated with autosomal recessive early-onset Parkinson's disease (PD). While parkin has been implicated in the regulation of mitophagy and proteasomal degradation, the precise mechanism leading to neurodegeneration in both sporadic and familial PD upon parkin loss-of-function remains unknown. Cultures of isogenic induced pluripotent stem cell (iPSC) lines with and without PARK2 knockout (KO) enable mechanistic studies of the effect of parkin deficiency in human dopaminergic neurons. We used such cells to investigate the impact of PARK2 KO on the lysosomal compartment and found a clear link between parkin deficiency and lysosomal alterations. PARK2 KO neurons exhibited a perturbed lysosomal morphology with enlarged electron-lucent lysosomes and an increased lysosomal content, which was exacerbated by mitochondrial stress and could be ameliorated by antioxidant treatment. We also found decreased lysosomal enzyme activity and autophagic perturbations, suggesting an impairment of the autophagy-lysosomal pathway in parkin-deficient cells. Interestingly, activity of the GBA-encoded enzyme, β-glucocerebrosidase, was increased, suggesting the existence of a compensatory mechanism. In conclusion, our data provide a unique characterization of the morphology, content, and function of lysosomes in PARK2 KO neurons and reveal an important new connection between mitochondrial dysfunction and lysosomal dysregulation in PD pathogenesis.
Project description:Calcium regulation is a critical process in neurons, and Ca2+ signaling is a major contributor to neurological disorders including Parkinson's disease (PD). Here, combining calcium imaging with whole-cell Ca2+ current recording, we provide a detailed protocol for measuring Ca2+ homeostasis in dopaminergic (DA) neurons derived from human induced pluripotent stem cells (hiPSCs). This approach can be applied to investigate the role of Ca2+ homeostasis in neuronal functionality as well as in disease processes. For complete details on the use and execution of this protocol, please refer to Kim et al. (2020).
Project description:Recent advances in human embryonic stem cell (ESC) and induced pluripotent stem cell (iPSC) biology enable generation of dopaminergic neurons for potential therapy and drug screening. However, our current understanding of molecular and cellular signaling that controls human dopaminergic development and function is limited. Here, we report on a whole genome analysis of gene expression during dopaminergic differentiation of human ESC/iPSC using Illumina bead microarrays. We generated a transcriptome data set containing the expression levels of 28,688 unique transcripts by profiling five lines (three ESC and two iPSC lines) at four stages of differentiation: (1) undifferentiated ESC/iPSC, (2) neural stem cells, (3) dopaminergic precursors, and (4) dopaminergic neurons. This data set provides comprehensive information about genes expressed at each stage of differentiation. Our data indicate that distinct pathways are activated during neural and dopaminergic neuronal differentiation. For example, WNT, sonic hedgehog (SHH), and cAMP signaling pathways were found over-represented in dopaminergic populations by gene enrichment and pathway analysis, and their role was confirmed by perturbation analyses using RNAi (small interfering RNA of SHH and WNT) or small molecule [dibutyryl cyclic AMP (dcAMP)]. In summary, whole genome profiling of dopaminergic differentiation enables systematic analysis of genes/pathways, networks, and cellular/molecular processes that control cell fate decisions. Such analyses will serve as the foundation for better understanding of dopaminergic development, function, and development of future stem cell-based therapies.
Project description:Human induced pluripotent stem cells can be differentiated into dopaminergic neurons (Dopa.4U). Dopa.4U neurons expressed voltage-gated NaV and KV channels and showed neuron-like spontaneous electrical activity. In automated patch clamp measurements with suspended Dopa.4U neurons, delayed rectifier K+ current (delayed KV) and rapidly inactivating A-type K+ current (fast KV) were identified. Examination of the fast KV current with inhibitors yielded IC50 values of 0.4 mM (4-aminopyridine) and 0.1 mM (tetraethylammonium). In manual patch clamp measurements with adherent Dopa.4U neurons, fast KV current could not be detected, while the delayed KV current showed an IC50 of 2 mM for 4-aminopyridine. The NaV channels in adherent and suspended Dopa.4U neurons showed IC50 values for tetrodotoxin of 27 and 2.9 nM, respectively. GABA-induced currents that could be observed in adherent Dopa.4U neurons could not be detected in suspended cells. Application of current pulses induced action potentials in approx. 70 % of the cells. Our results proved the feasibility of automated electrophysiological characterization of neuronal cells.
Project description:Neuronal migration is necessary in the process of the formation of brain architecture. Recently, we demonstrated that human induced pluripotent stem cell (iPSC)-derived dopaminergic neurons exhibit directional migration in vitro. However, it remains unclear how the cell shape is involved in their migration. In this study, we performed live imaging analyses using human iPSC-derived dopaminergic neurons. Our automated method, which can automatically identify the cell body shape and the cell position at specific time points, revealed that healthy iPSC-derived dopaminergic neurons migrate according to their shape. This migration behavior was out of accord in neurons derived from iPSCs carrying an RELN deletion. Our findings provide a novel theory that cell body orientation is related to the stability of movement direction for human dopaminergic neurons, under the regulation of RELN.
Project description:The transplantation of dopaminergic (DA) progenitors derived from pluripotent stem cells improves the behavior of Parkinson's disease model animals. However, the survival of DA progenitors is low, and the final yield of DA neurons is only approximately 0.3%-2% the number of transplanted cells. Zonisamide (ZNS) increases the number of survived DA neurons upon the transplantation of mouse-induced pluripotent stem (iPS) cell-derived DA progenitors in the rat striatum. In this study, we induced DA progenitors from human iPS cells and transplanted them into the striatum of female rats with daily administration of ZNS. The number of survived DA neurons was evaluated 1 and 4 months after transplantation by immunohistochemistry, which revealed that the number of survived DA neurons was significantly increased with the administration of ZNS. To assess the mechanism of action of ZNS, we performed a gene expression analysis to compare the gene expression profiles in striatum treated with or without ZNS. The analysis revealed that the expression of SLIT-and NTRK-like protein 6 (SLITRK6) was upregulated in rat striatum treated with ZNS. In conclusion, ZNS promotes the survival of DA neurons after the transplantation of human-iPS cell-derived DA progenitors in the rat striatum. SLITRK6 is suggested to be involved in this supportive effect of ZNS by modulating the environment of the host brain.
Project description:BackgroundParkinson's disease (PD) is the second most common age-dependent neurodegenerative disease that causes motor and cognitive disabilities. This disease is associated with a loss of dopamine content within the putamen, which stems from the degeneration of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNc). Several approved drugs are available that can effectively treat symptoms of PD. However, long-term medical management is often complicated and does not delay or halt disease progression. Alternatively, cell replacement strategies can address these shortcomings and provide dopamine where it is needed. Although using human pluripotent stem cells (hPSCs) for treatment of PD is a promising alternative, no consensus in the literature pertains to efficacy concerns of hPSC-based therapy for PD. This systematic review aims to investigate the efficacy of primate PSC-derived DA progenitor transplantation to treat PD in preclinical studies.MethodsThis is a systematic review of preclinical studies in animal models of PD. We intend to use the following databases as article sources: MEDLINE (via PubMed), Web of Science, and SCOPUS without any restrictions on language or publication status for all related articles published until the end of April 2021. Two independent reviewers will select the titles and abstracts, extract data from qualifying studies, and assess the risk of bias using the SYstematic Review Centre for Laboratory animal Experimentation (SYRCLE) risk of bias tool and the Collaborative Approach to Meta-Analysis and Review of Animal Data from Experimental Studies (CAMARADES) checklist. Apomorphine-induced rotation test (APO-IR) and amphetamine-induced rotation test (AMP-IR) are defined as the primary outcomes. The standardized mean difference (SMD) by Hedges' g method (r) and odds ratio (OR) and related 95% confidence interval (CI) will be calculated to determine the size effect of the treatment. The heterogeneity between studies will be calculated by "I2 inconsistency of values and Cochran's Q statistical test," where I2 > 50% and/or p < 0.10 suggests high heterogeneity. Meta-analyses of random effects will be run when appropriate.DiscussionThis study will present an overview of preclinical research on PSCs and their therapeutic effects in PD animal models. This systematic review will point out the strengths and limitations of studies in the current literature while encouraging the funding of new studies by public health managers and governmental bodies.
Project description:Colinear HOX expression during hindbrain and spinal cord development diversifies and assigns regional neural phenotypes to discrete rhombomeric and vertebral domains. Despite the precision of HOX patterning in vivo, in vitro approaches for differentiating human pluripotent stem cells (hPSCs) to posterior neural fates coarsely pattern HOX expression thereby generating cultures broadly specified to hindbrain or spinal cord regions. Here, we demonstrate that successive activation of fibroblast growth factor, Wnt/?-catenin, and growth differentiation factor signaling during hPSC differentiation generates stable, homogenous SOX2(+)/Brachyury(+) neuromesoderm that exhibits progressive, full colinear HOX activation over 7 days. Switching to retinoic acid treatment at any point during this process halts colinear HOX activation and transitions the neuromesoderm into SOX2(+)/PAX6(+) neuroectoderm with predictable, discrete HOX gene/protein profiles that can be further differentiated into region-specific cells, e.g., motor neurons. This fully defined approach significantly expands capabilities to derive regional neural phenotypes from diverse hindbrain and spinal cord domains.