Sephin1 alleviates white matter injury by protecting oligodendrocyte after intracerebral hemorrhage

Background White matter injury (WMI) caused by intracerebral hemorrhage (ICH) is a major neuropathological feature closely associated with neurological impairments such as motor and sensory dysfunction. Oligodendrocytes (OLs), which are responsible for repairing WMI, also suffer severe death resulting from the compression of hematoma and secondary neuroinflammation after ICH. Sephin1, a selective inhibitor of PPP1R15A, has been shown to reduce general protein synthesis and protect OLs by prolonging the integrated stress response (ISR). We aimed to evaluate the effectiveness of Sephin1 in protecting OLs in experimental ICH mice and primary OLs and microglia co-cultures. Methods We first determined the performance of ICH mice treated with Sephin1 or vehicle in multiple behavioral tests. To investigate dynamic changes in the number of OLs surrounding the hematoma after ICH, we labeled and tracked apoptotic, proliferating, and mature OLs using immunofluorescence staining. Results Sephin1 treatment improved long-term neurological function after ICH, which was accompanied by a significant alleviation of WMI in the perihematomal region. Our data indicated that Sephin1 dramatically increased the population of OLs in the perihematomal region after ICH by inhibiting OL apoptosis and promoting OL proliferation. Moreover, Sephin1 treatment attenuated neuroinflammation after ICH by inhibiting microglial polarization to the M1 phenotype. In vitro , a co-culture model of primary OLs and microglia demonstrated that Sephin1 preserved the viability of OLs under pro-inflammatory conditions. Conclusions Our observations suggest that Sephin1 is a promising therapeutic drug to preserve the OLs and alleviate WMI around the hematoma in ICH, highlighting its translational potential to improve long-term neurological recovery in hemorrhagic stroke.