Parkinson’s disease (PD) is a long-term degenerative disease of the central nervous system (CNS) that primarily affects the motor system. So far there is no effective treatment for PD, only some drugs, surgery, and comprehensive treatment can alleviate the symptoms of PD. Stem cells derived from human exfoliated deciduous teeth (SHED), mesenchymal stem cells derived from dental pulp, may have promising potential in regenerative medicine. In this study, we examine the therapeutic effect of SHED-derived conditioned medium (SHED-CM) in a rotenone-induced PD rat model. Intravenous administration of SHED-CM generated by standardized procedures significantly improved the PD symptoms accompanied with increased tyrosine hydroxylase amounts in the striatum, and decreased α-synuclein levels in both the nigra and striatum, from rotenone-treated rats. In addition, this SHED-CM treatment decreased both Iba-1 and CD4 levels in these brain areas. Gene ontology analysis indicated that the biological process of genes affected by SHED-CM was primarily implicated in neurodevelopment and nerve regeneration. The major constituents of SHED-CM included insulin-like growth factor binding protein-6 (IGFBP-6), tissue inhibitor of metalloproteinase (TIMP)-2, TIMP-1, and transforming growth factor β1 (TGF-β1). RNA-sequencing (RNA-seq) and Ingenuity Pathway Analysis (IPA) revealed that these factors may ameliorate PD symptoms through modulating the cholinergic synapses, calcium signaling pathways, serotoninergic synapses, and axon guidance. In conclusion, our data indicate that SHED-CM contains active constituents that may have promising efficacy to alleviate PD.

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Direct chemical reprogramming provides a potentially scalable approach for generating retinal lineage-associated cells without genetic manipulation. In this study, human Tenon’s capsule fibroblasts were converted into retinal progenitor-like cells using a defined small-molecule cocktail. Retinal lineage-associated features were evaluated by immunofluorescence staining, quantitative reverse-transcription PCR, Western blot analysis, and bulk RNA sequencing, showing upregulation of neural and retinal markers, including VSX2, and transcriptomic remodeling consistent with transcriptional features associated with neuronal differentiation programs. Functional responsiveness was assessed by glutamate-evoked intracellular calcium imaging, revealing glutamate-responsive intracellular calcium dynamics in induced cells but not in parental fibroblasts. For in vivo assessment, induced cells were delivered via intravitreal transplantation in Wistar rats and subretinal transplantation in Long–Evans rats. One month after transplantation, structural and functional evaluations using optical coherence tomography, electroretinography, and histological analyses showed localized alterations in retinal structure at the subretinal injection site, while no significant differences were observed in scotopic ERG responses under the present experimental conditions. In contrast, fibroblast transplantation showed more prominent structural alterations under similar conditions. Human nuclei-positive signals were detectable in a subset of eyes, exhibiting focal and heterogeneous distribution within retinal regions at the one-month endpoint. Collectively, these suggest the induction of retinal lineage-associated molecular and functional features, with short-term functional tolerability observed in vivo under the present experimental conditions.