Neuronal Soluble Fas Ligand Drives M1-Microglia Polarization after Cerebral Ischemia.
This study explored sFasL expression in neurons and the potential role of neuronal sFasL in modulating the microglial phenotypes.



In vivo, middle cerebral artery occlusion (MCAO) was induced in both FasL-mutant (gld) and wild-type (wt) mice. In vitro, primary cortical neuron or microglia or coculture from wt/gld mice was subjected to oxygen glucose deprivation (OGD). sFasL level in the supernatant was evaluated by ELISA. Neuronal-conditioned medium (NCM) or exogenous sFasL was applied to primary microglia with or without FasL neutralizing antibody. Protein expression of JAK2/STAT3 and NF-κB pathways were determined by Western blot. The effect of microglia phenotype from wt/gld mice on the fate of ischemic neurons was further elucidated.



In vivo, compared with wild-type mice, M1 markers (CD16, CD32 and iNOS) were attenuated in gld mice after MCAO. In vitro, post-OGD neuron released more sFasL. Both post-OGD NCM and exogenous sFasL could trigger M1-microglial polarization. However, this M1 phenotype shift was partially blocked by utilization of FasL neutralizing antibody or gld NCM. Consistently, JAK2/STAT3 and NF-κB signal pathways were both activated in microglia after exogenous sFasL treatment. Compared with wild-type mice, M1-conditioned medium prepared from gld mice protected neuron against OGD injury.



Ischemic neurons release sFasL, which contributes to M1-microglial polarization. The underlying mechanisms may involve the activation of JAK2/STAT3 and NF-κB signaling pathways.
Department of Neurology, Drum Tower Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China.
Hai-Lan
HL
Meng
Department of Neurology, Drum Tower Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China.
Xiao-Xi
XX
Li
Department of Neurology, Drum Tower Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China.|The State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, Jiangsu, China.|Jiangsu Key Laboratory for Molecular Medicine, Nanjing University Medical School, Nanjing, Jiangsu, China.|Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing, China.|Nanjing Neuropsychiatry Clinic Medical Center, Nanjing, China.
Yan-Ting
YT
Chen
Department of Neurology, Drum Tower Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China.
Lin-Jie
LJ
Yu
Department of Neurology, Drum Tower Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China.
He
H
Zhang
Department of Neurology, Drum Tower Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China.
Jia-Min
JM
Lao
Department of Neurology, Drum Tower Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China.|The State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, Jiangsu, China.|Jiangsu Key Laboratory for Molecular Medicine, Nanjing University Medical School, Nanjing, Jiangsu, China.|Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing, China.|Nanjing Neuropsychiatry Clinic Medical Center, Nanjing, China.
Xin
X
Zhang
Department of Neurology, Drum Tower Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China.|The State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, Jiangsu, China.|Jiangsu Key Laboratory for Molecular Medicine, Nanjing University Medical School, Nanjing, Jiangsu, China.|Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing, China.|Nanjing Neuropsychiatry Clinic Medical Center, Nanjing, China.
Yun
Y
Xu
D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism; D015687:Cell Hypoxia / Q000235:genetics; D016764:Cell Polarity / Q000235:genetics*; D002540:Cerebral Cortex / Q000166:cytology; D017077:Culture Media, Conditioned / Q000494:pharmacology; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D004622:Embryo, Mammalian; D053222:Fas Ligand Protein / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000235:genetics; D005947:Glucose / Q000172:deficiency; D020244:Infarction, Middle Cerebral Artery / Q000235:genetics* / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D017628:Microglia / Q000737:chemistry / Q000145:classification / Q000473:pathology*; D009154:Mutation / Q000235:genetics; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics
D015703:Antigens, CD; D017077:Culture Media, Conditioned; D053222:Fas Ligand Protein; D052247:Nitric Oxide Synthase Type II; C077623:Ptgs2 protein, mouse; D051546:Cyclooxygenase 2; D005947:Glucose
Inflammation; Ischemic stroke; Microglia; Neuron; Soluble FasL