PTX3 secreted by human adipose-derived stem cells promotes dopaminergic neuron repair in Parkinson's disease via inhibiting apoptosis

Background Adipose-derived human mesenchymal stem cells (hADSCs) transplantation has recently emerged as a promising method in the treatment of Parkinson's disease (PD), however, the mechanism underlying has not been fully illustrated. Methods In this study, the therapeutic effects of the striatum stereotaxic injected hADSCs in 6-OHDA-induced mouse model were evaluated. Furthermore, an in vitro model of PD was constructed using tissue-organized brain slices. And the therapeutic effect was evaluated by co-culture of hADSCs and 6-OHDA-constructed brain slice. Within the analysis of hADSCs' exocrine proteins through RNA-seq, Human protein cytokine arrays and label-free quantitative proteomics, key extracellular factors were identified in hADSCs secretion environment.The degeneration of DA neurons and apoptosis were measured in PD samples in vivo and vitro models, and the beneficial effects were evaluated through quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blot,Fluoro-Jade C, Tunel assay and immunofluorescence analysis. Results In this study, we discovered that hADSCs protected the dopaminergic (DA) neurons in vivo and vitro models.we identified Pentraxin3 (PTX3) as a key extracellular factor in hADSCs secretion environment. Moreover, we found that human recombinant Pentraxin3 (rhPTX3) treatment could rescue the physiological behaviour of the PD mice in-vivo, as well as prevent DA neurons from death and increase the neuronal terminals in the Ventral tegmental area (VTA) + substantia nigra pars compacta (SNc) and striatum (STR) on the PD brain slices in-vitro. Furthermore, within testing on the pro-apoptotic markers of PD mice brain following the treatment of rhPTX3, we found that rhPTX3 can prevent the apoptosis and the degeneration of DA neurons. Conclusions Overall, the current study investigated that PTX3, a hADSCs secreted protein, played a potential role in protecting the DA neurons from apoptosis and degeneration in PD progression as well as improving the motor performances in PD mice to give a possible mechanism of how hADSCs works in the cell replacement therapy in PD. Importantly, our study also provided potential translational implications for the development of PTX3-based therapeutics in PD.