RESUMO
Ischemic stroke is an acute and serious cerebrovascular accident.Neurodegenerative disorders are characterized by progressive degeneration of neu-rons in the central nervous system(CNS),resulting in severe disability and death.Myelin is essential for the health and function of neuronal axons.Oligodendrocytes,the myelinating cells of CNS,are vulnerable to ischemia and neurodegenerative disorders.G protein-coupled receptor 17(GPR17)is a dual receptor activated by uracil nucleotides/cysteinyl leukotrienes(CysLTs).Abnormal GPR17 activation contributes to oligodendrocyte dysfunc-tion and axonal damage.Gelosa et al.reported that CysLT1 receptor antagonist montelukast increased the recruitment and proliferation of oligodendrocyte precursor cells(OPCs)at the acute phase after ischemic stroke.Similarly,a study showed that montelukast stimulated neural progenitor proliferation and hippocampal neuro-genesis of aged rats through inhibition of GPR17.These results were supported by several studies on neurode-generative diseases.The authors showed that pharmaco-logical blockade of GPR17 with CysLT1 or CysLT2 recep-tor antagonists(montelukast or HAMI3379)improved oli-godendrocyte function and fiber connectivity,highlighting GPR17 as a potential therapeutic target in oligodendro-cyte protection and remyelination.Recently,growing evi-dence has revealed a significant interaction between mi-croglia and oligodendrocytes in CNS injury and disease.It was reported that M2 microglia promoted,while M1 microglia inhibited oligodendrogenesis,OPCs maturation and remyelination.Microglia-mediated neuroinflamma-tion,considered as an important pathological event,neg-atively affected OPCs fate and function in experimental neurological disorders.This was further corroborated by later studies.It was recently reported that montelukast enhanced OPCs differentiation and maturation by upreg-ulating the number of M2 microglia at chronic phase of brain ischemia.In line with the above results,inhibition of microglial inflammation by montelukast was shown to be responsible for neurite outgrowth.Although the exact mechanisms were not fully clarified,these results indi-cate that montelukast may indirectly promote OPCs dif-ferentiation and remyelination by a microglia-dependent manner.It has been widely accepted that CysLT1,CysLT2 and GPR17 receptors are localized in various cell types and their expression are upregulated after brain damage.Therefore,it is likely that CysLT receptor antagonists confer neuroprotection by targeting different receptors and multiple cell functions.Many studies have reported that CysLT receptor antagonists promote protec-tion of oligodendrocytes by inhibiting GPR17.Moreover,they may improve OPCs differentiation and neuronal sur-vival by regulating CysLTs-mediated microglial activation.Altogether,these data open novel perspectives in the treatment of cerebral ischemia and neurodegenerative diseases.