CKLF1 aggravates focal cerebral ischemia injury at early stage partly by modulating microglia/macrophage toward M1 polarization

OBJECTIVE To investigate the CKLF1 mediated expression of microglia/macrophage phenotypes in vitro and in vivo,discussing the involved pathway.METHODS In vitro,primary microglia isolated from mice cortex were used to study the effects of CKLF1 by qPCR analysis and immunofluorescence staining.In vivo,WT C57 and CKLF1 deficient mice were used to explore the effects of CKLF1.TTC staining,MRI and Nissl staining were applied to examine the infarction or neuron loss.Zea longa test was used to evaluate the neurological deficit of mice.Western blotting was used to investigate the changes of specific protein and discuss the involved pathway.We also used qPCR analysis and immunofluorescence staining for polarization markers to determine the effects of CKLF1.RESULTS CKLF1 could drive primary microglia to M1 phenotype for 24 h stimulation in primary microglia.In mice transient ischemic stroke model,CKLF1 attenuated ischemic injury,and accompanied by promoting microglia/macrophage toward M1 polarization.Increased expression of pro-inflammatory cytokines and decreased expression of neurotropic factors and anti-inflammatory cytokines were observed in mice subjected to cerebral ischemia with C27.Moreover,NF-κB activation enhancement was detected in C27 modulated M1 polarization effects.CONCLUSION CKLF1 is an important mediator of driving M1 phenotype of microglia/macrophage at early stage of cerebral ischemic injury,contributing to aggravation of cerebral ischemia injury,which closely related to microglia/macrophage M1 polarization guided inflammatory response.Targeting CKLF1 has the potential to treat ischemic stroke.