2022, Vol. 26 ›› Issue (30): 4840-4846

Transdifferentiation of rat astrocytes into neurons induced by ectodermal mesenchymal stem cells-derived extracellular vesicles

Guan Shihao1, Huang Yonghui1, Gong Aihua2, Cao Xingbing1, Sun Haitao1, Cai Chuang1   

Abstract: BACKGROUND: Spinal cord injury will lead to the proliferation of astrocytes, resulting in glial scar that hinders the formation of axons, and the local inflammatory microenvironment further aggravates the death of neurons. Therefore, converting astrocytes into neurons reduces the proliferation of astrocytes and increases the number of neurons — killing two birds with one stone. However, it has not been reported whether ectodermal mesenchymal stem cells-derived extracellular vesicles can induce astrocytes to differentiate into neurons.  
OBJECTIVE: To explore whether ectodermal mesenchymal stem cells-derived extracellular vesicles can induce astrocytes to transdifferentiate into neurons.
METHODS:   (1) Ectodermal mesenchymal stem cells derived from nasal mucosa tissue of SD rats were cultured by the tissue explant culture and identified according to their morphology and immunofluorescence. The cell supernatant was collected to extract extracellular vesicles, which were identified by particle size analysis, transmission electron microscopy, and western blot assay. (2) The astrocytes of SD rats were cultured and identified by trypsin digestion technique. (3) Astrocytes were divided into two groups for intervention. Ectodermal mesenchymal stem cells-derived extracellular vesicles (mass concentration:
1 g/L, volume: 66 μL added into 2 mL medium) and PBS of the same volume were added into astrocytes for 72 hours. (4) The expression levels of neuron markers neuron-specific enolase and neurofilament 200 were detected by immunofluorescence, real-time fluorescence quantitative PCR, and western blot assay.  
RESULTS AND CONCLUSION: (1) Ectodermal mesenchymal stem cells presented typical spindle shape and high expression of marker proteins CD44, Nestin, and Vimentin. The ectodermal mesenchymal stem cells-derived extracellular vesicles exhibited classic tea receptor-like morphology. The particle size distribution ranged from 30 nm to 200 nm. Western blot assay demonstrated positive expression of marker proteins CD9, CD63, and TSG101. (2) Astrocytes were star-shaped and highly expressed the marker protein glial fibrillary acidic protein. (3) Compared with the control group, there were more neuron-like cells in the ectodermal mesenchymal stem cells-derived extracellular vesicles group. The cell bodies were spindle shaped and full; the processes increased and became longer; and the neuron-specific enolase and neurofilament 200 were highly expressed (P < 0.05). (4) The above results suggest that ectodermal mesenchymal stem cells-derived extracellular vesicles induce astrocytes to transdifferentiate into neurons.
Key words: mesenchymal stem cell, extracellular vesicle, central nervous system, astrocytes, neurons, neuron-specific enolase, neurofilament 200, transdifferentiation