To date, it remains poorly understood whether astrocytes can be easily reprogrammed into neurons.
Mash1 and Brn2 have been previously shown to cooperate to reprogram fibroblasts into neurons.
Dr. Yongjun Wang and team from Shanghai University of Traditional Chinese Medicine in China found that Brn2 was expressed in astrocytes from 2-month-old Sprague-Dawley rats, but Mash1 was not detectable. Thus, the researchers hypothesized that Mash1 alone could be used to reprogram astrocytes into neurons.
Murine stem cell virus (MSCV)-Mash1 recombinant plasmid was constructed and transfected into GP2-293t cells to produce retrovirus. One week later, the changes in morphology of astrocytes were detectable, which showed typical neuronal characteristics. Moreover, β-tubulin expression levels were significantly higher in astrocytes expressing Mash1 than in control cells.
These results, published in Neural Regeneration Research (Vol. 9, No. 1, 2014), indicate that Mash1 alone can reprogram astrocytes into neurons. This method determined an easier process of reprogramming through the endogenous expression of important transcription factors, which avoids malignant transformation due to the spontaneous reactivation of viral transgenes.