Hwan Choi

p53 signalling mediates acupuncture-induced neuroprotection in Parkinson's disease

Parkinsons disease (PD) is a progressive neurodegenerative disorder associated with a selective loss of dopamine (DA) neurons in the substantia nigra of the midbrain. Recently, it has been demonstrated that acupuncture treatment has protective effects in PD. However, to date, the molecular mechanisms underlying acupunctures effect on DA neuronal protection are largely unknown. In this study, we report that p53 signalling mediates the protective effects of acupuncture treatment in a mouse model of PD. We found that the acupuncture treatment in the mouse PD model results in significant recovery to the normal in the context of behaviour and molecular signatures. We found that the gene network associated with p53 signalling is closely involved in the protective effects of acupuncture treatment in PD. Consistent with this idea, we demonstrated that specific knockout of the p53 gene in the midbrain DA neurons abrogates the acupuncture induced protective effects in the mouse model of PD. Thus, these data suggest that p53 signalling mediates the protective effects of acupuncture treatment in PD.

Generation of Integration-Free Induced Neurons Using Graphene Oxide-Polyethylenimine

Direct conversion of somatic cells into induced neurons (iNs) without inducing pluripotency has great therapeutic potential for treating central nervous system diseases. Reprogramming of somatic cells to iNs requires the introduction of several factors that drive cell-fate conversion, and viruses are commonly used to deliver these factors into somatic cells. However, novel gene-delivery systems that do not integrate transgenes into the genome are required to generate iNs for safe human clinical applications. In this study, it is investigated whether graphene oxide-polyethylenimine (GO-PEI) complexes are an efficient and safe system for messenger RNA delivery for direct reprogramming of iNs. The GO-PEI complexes show low cytotoxicity, high delivery efficiency, and directly converted fibroblasts into iNs without integrating factors into the genome. Moreover, in vivo transduction of reprogramming factors into the brain with GO-PEI complexes facilitates the production of iNs that alleviated Parkinsons disease symptoms in a mouse model. Thus, the GO-PEI delivery system may be used to safely obtain iNs and could be used to develop direct cell reprogramming-based therapies for neurodegenerative diseases.

Ebf3-miR218 regulation is involved in the development of dopaminergic neurons

The development of midbrain dopaminergic (DA) neurons is a complex process that requires the precise spatial and temporal expression of numerous genes. Here, we report that Ebf3, a transcription factor, plays a critical role in the terminal development of DA neurons. We found a specific upregulation of Ebf3 in Dicer knockout midbrain DA neurons and dynamic patterns of Ebf3 expression during the development of DA neurons. We further demonstrated that the overexpression of Ebf3 at the neural precursor stage of embryonic stem (ES) differentiation induces a significant increase in the number of TH+ DA neurons, whereas the suppression of Ebf3 leads to significant reduction in the development of TH+ DA neurons. Additionally, we found that Ebf3 is a candidate target for miR218 during DA neuronal development, such that the regulation of Ebf3 expression by miR218 controls the terminal differentiation of DA neurons. Thus, our data suggest that complex transcription factor-miRNA regulation is critical for the development of midbrain DA neurons.

Modeling of Autism Using Organoid Technology

Autism is a neurodevelopmental disease caused by multiple mutations during development. However, a suitable disease model to study the molecular pathway of disease onset and progression is not available. Although many studies have used human stem cells such as induced pluripotent stem cells and embryonic stem cells to investigate the disease pathogenesis, these stem cell techniques are limited in their abilities to study the pathology and mechanism of pathogenesis of neurodevelopmental diseases such as autism. Therefore, researchers are focusing on the strengths of three-dimensional (3D) structures mimicking organs, organoids, for modeling autism. In this review, we highlight the advantages of 3D organoid systems to investigate the mechanisms of the pathogenesis of autism. Further, because the onset of autism is determined by genetic background, we suggest the application of the clustered regularly interspersed short palindromic repeat-associated protein 9 (CRISPR/Cas9) technique for genome editing in 3D organoid systems to study mutations that cause autism. We propose that 3D organoid systems combined with the CRISPR/Cas9 technique may advance autism research.