Reprogramming activated astrocytes into GABAergic neurons to treat trigeminal neuralgia

Trigeminal neuralgia (TN) is the most common type of cranial neuralgia. Currently, there remains a significant gap in the availability of effective and safe treatment options in clinical practice. Transdifferentiation of proliferating activated astrocytes into inhibitory neurons is a potential therapeutic strategy for central nervous system diseases. GABAergic neurons are one of the most type of prevalent inhibitory neurons. This study aims to reprogram proliferating astrocytes in the spinal trigeminal subnucleus caudalis (SpVc) into GABAergic neurons, could improve neuronal excitation-inhibition balance, alleviate pain, which serve as a potential treatment for trigeminal neuralgia. A chronic constriction injury of the distal infraorbital nerve (CCI-dION) was induced in the infraorbital branch of the trigeminal nerve to create a rat model of TN. Adeno-associated viruses were used to overexpress transcription factors Sox2 and Mash1 in astrocytes. The changes in astrocytes and GABAergic neurons in the SpVc region were detected by immunofluorescence, Western blotting, qPCR, and electron microscopy. The mechanical pain threshold testing was used to assess rat TN. In the SpVc region of CCI-dION rats, astrocytes showed proliferation and activation, and the number of GABAergic neurons decreased significantly. Overexpressing Sox2 and Mash1 in astrocytes led to a significant transdifferentiation into GABAergic neurons, which - improved the mechanical pain threshold in CCI-dION rats. Furthermore, fluorocitrate-mediated astrocyte deactivation abolished both the neuronal reprogramming and the analgesic effects, underscoring the essential role of astrocytes in this process. These findings suggest that overexpressing Sox2 and Mash1 in astrocytes led to a significant transdifferentiation into GABAergic neurons, which significantly improved the mechanical pain threshold in CCI-dION rats. Thus, this approach has the potential to provide a new treatment for TN.