Research on the use of neural stem cells for treating neurological diseases

다국어 초록 (Multilingual Abstract)

Neural crest stem cells (NCSCs) are multipotent cells that can differentiate into a broad array of cell types, including peripheral neurons, melanocytes, and mesenchymal stem cells (MSCs). Derivation of NCSCs from human pluripotent stem cells (hPSCs) has been induced by regulation of various signaling pathways, such as TGF-β/Activin A/Nodal, BMP, WNT, Notch, and FGF pathways. Many protocols used WNT activation in combination of dual SMAD inhibition or inhibition of only TGF-β/Activin A/Nodal signaling: WNT activation is required because conventional dual SMAD inhibition generates only small number of NCSCs.
In this study, by modulating BMP signaling of dual SMAD inhibition, we generated large numbers of HNK+p75+ NCSCs in the absence of WNT activation. We showed that spherical cell clumps, a distinct structure formed after differentiation, mainly consisted of p75high NCSC population, which enabled us to easily isolated p75high NCSCs by mechanical dissection.
We displayed a significant difference between p75high and p75low cells and showed that both p75high and p75low cells differentiated into MSC, while only p75high cells had additional capability to become peripheral neurons.
This study will provide a framework for generation and isolation of NCSC populations for effective cell therapy for peripheral neuropathies and MSC-based cell therapy.

다국어 초록 (Multilingual Abstract)

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons in the midbrain. Mitochondrial dysfunction has been implicated in the pathogenesis of PD, and drugs that target mitochondrial function may provide therapeutic benefit. However, current in vitro models for PD drug screening do not fully recapitulate the complexity of the human brain. In this study, we generated midbrain organoids by mutating the park2 gene with CRISPR in human pluripotent stem cells and characterized dopaminergic neurodevelopmental and mitochondrial function. Then, mitochondrial dysfunction was induced using CCCP, a mitochondrial plasma membrane depolarizing drug, and used in the study. Using this model, we screened a library of drugs that target mitochondrial function and identified several compounds that improved mitochondrial recovery and dopaminergic neuron survival in PD model. These findings suggest that midbrain organoids can be used as a platform for drug screening in PD and highlight the potential of targeting mitochondrial function for PD therapy.

다국어 초록 (Multilingual Abstract)

Glioblastoma multiforme (GBM) is a devastating brain tumor. Epidermal growth factor receptor variant type III (EGFRvIII) is the most common mutation of EGFR and is found in ~25% of all GBMs. Since EGFRvIII is mostly found in GFAP+ astrocytic tumors, such as GBM, we hypothesized there may be a connection between EGFRvIII and astrogenesis. In this study, we used CRISPR/Cas9 to introduce monoallelic or biallelic EGFRvIII mutations in hESCs which were used to generate cerebral organoids. Whereas EGFRvIII-organoids had abundant astrocytes, wt-organoids had no detectable astrocytes at day 49. In contrast, TUJ1+ neurons were more abundant in the wt-organoids than EGFRvIII-organoids. In addition, the EGFRvIII-organoids were larger and had more Ki67+ cells than the wt-organoids, indicating enhanced cell proliferation as a result of the mutation. In summary, EGFRvIII mutations induced astrogenesis and were associated with massive cell proliferation. These results provide new insights into the role of the EGFRvIII mutation in gliomagenesis.

다국어 초록 (Multilingual Abstract)

Human pluripotent stem cell-derived neural progenitor cells (NPCs) have the potential to recover from nerve injury. We previously reported that human placenta-derived mesenchymal stem cells (PSCs) have neuroprotective effects. To evaluate the potential benefit of NPCs, we compared them to PSCs using R28 cells under hypoxic conditions and a rat model of optic nerve injury. NPCs and PSCs (2 × 106 cells) were injected into the subtenon space. After 1, 2, and 4 weeks, we examined changes in target proteins in the retina and optic nerve. NPCs significantly induced vascular endothelial growth factor (Vegf) compared to age-matched shams and PSC groups at 2 weeks; they also induced neurofilaments in the retina compared to the sham group at 4 weeks. In addition, the expression of brain-derived neurotrophic factor (Bdnf) was high in the retina in the NPC group at 2 weeks, while expression in the optic nerve was high in both the NPC and PSC groups. The low expression of ionized calcium-binding adapter molecule 1 (Iba1) in the retina had recovered at 2 weeks after NPC injection and at 4 weeks after PSC injection. The expression of the inflammatory protein NLR family, pyrin domain containing 3 (Nlrp3) was significantly reduced at 1 week, and that of tumor necrosis factor-α (Tnf-α) in the optic nerves of the NPC group was lower at 2 weeks. Regarding retinal ganglion cells, the expressions of Brn3a and Tuj1 in the retina were enhanced in the NPC group compared to sham controls at 4 weeks. NPC injections increased Gap43 expression from 2 weeks and reduced Iba1 expression in the optic nerves during the recovery period. In addition, R28 cells exposed to hypoxic conditions showed increased cell survival when cocultured with NPCs compared to PSCs. Both Wnt/β-catenin signaling and increased Nf-ĸb could contribute to the rescue of damaged retinal ganglion cells via upregulation of neuroprotective factors, microglial engagement, and anti-inflammatory regulation by NPCs. This study suggests that NPCs could be useful for the cellular treatment of various optic neuropathies, together with cell therapy using mesenchymal stem cells.

참고문헌 (Reference)

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