Enhancing Remyelination by Blockade of Astrocytic <scp>P2X1</scp> Receptors Signaling in Cuprizone‐Induced Demyelination Mouse Model

Demyelinating diseases such as multiple sclerosis (MS) are situations with the core feature of primary or secondary damage to myelin and oligodendrocytes (OLs) due to various insults including autoimmune attack and inflammation which ultimately lead to axonal injury and neurological dysfunction. Currently, immunomodulatory therapies for MS have very limited effects on disease progression and long-term prognosis. Therefore, pro-myelinating strategy has been attracting more and more attention. Astrocyte reactivation has been reported in many demyelination conditions and is supposed to play a duplex effect during demyelination and remyelination, while the detailed underlying mechanism remains unknown. Here, we report that reactive astrocytes in cuprizone-induced demyelination mice showed sustained upregulation of the expression of P2 purinergic receptor X1 (P2X1). Pharmacologic blockade of P2X1 receptor signaling by receptor-specific antagonist NF449 significantly enhanced/accelerated remyelination and altered new OL production dynamics. Furthermore, astrocyte-specific conditional knockout of the P2X1 gene promoted remyelination and led to early onset of new OL production. In addition, conditioned medium (CM) from ATP treated astrocyte culture that overexpressed P2X1 significantly hindered the differentiation of oligodendrocyte precursor cells (OPCs) in vitro compared to CM from empty vector virus-infected astrocytes with the same treatment, suggesting the secretion of certain inhibitory factors for OPC maturation and myelination by astrocytes with upregulated P2X1 receptor expression. Taken together, our study indicates that abnormal P2X1 receptor signaling in reactive astrocytes may be an important endogenous inhibitory factor for remyelination, and blockade of this pathway might be a potential target for pro-myelination therapy strategy for demyelinating diseases.