title: Lymphocyte cell kinase activation mediates neuroprotection during ischemic preconditioning.
abstract: The molecular mechanisms underlying preconditioning (PC), a powerful endogenous neuroprotective phenomenon, remain to be fully elucidated. Once identified, these endogenous mechanisms could be manipulated for therapeutic gain. We investigated whether lymphocyte cell kinase (Lck), a member of the Src kinases family, mediates PC. We used both in vitro primary cortical neurons and in vivo mouse cerebral focal ischemia models of preconditioning, cellular injury, and neuroprotection. Genetically engineered mice deficient in Lck, gene silencing using siRNA, and pharmacological approaches were used. Cortical neurons preconditioned with sublethal exposure to NMDA or oxygen glucose deprivation (OGD) exhibited enhanced Lck kinase activity, and were resistant to injury on subsequent exposure to lethal levels of NMDA or OGD. Lck gene silencing using siRNA abolished tolerance against both stimuli. Lck-/- mice or neurons isolated from Lck-/- mice did not exhibit PC-induced tolerance. An Lck antagonist administered to wild-type mice significantly attenuated the neuroprotective effect of PC in the mouse focal ischemia model. Using pharmacological and gene silencing strategies, we also showed that PKCε is an upstream regulator of Lck, and Fyn is a downstream target of Lck. We have discovered that Lck plays an essential role in PC in both cellular and animal models of stroke. Our data also show that the PKCε-Lck-Fyn axis is a key mediator of PC. These findings provide new opportunities for stroke therapy development.
authors.affiliation: Division of Cerebrovascular Diseases and Department of Neurology and Ophthalmology, Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: Ok-Nam
authors.initials: ON
authors.lastname: Bae
authors.forename: Krishnamurthy
authors.initials: K
authors.lastname: Rajanikant
authors.forename: Jiangyong
authors.initials: J
authors.lastname: Min
authors.forename: Jeremy
authors.initials: J
authors.lastname: Smith
authors.forename: Seung-Hoon
authors.initials: SH
authors.lastname: Baek
authors.forename: Kelsey
authors.initials: K
authors.lastname: Serfozo
authors.forename: Siamak
authors.initials: S
authors.lastname: Hejabian
authors.forename: Ki Yong
authors.initials: KY
authors.lastname: Lee
authors.forename: Mounzer
authors.initials: M
authors.lastname: Kassab
authors.forename: Arshad
authors.initials: A
authors.lastname: Majid
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000818:Animals; D002545:Brain Ischemia / Q000201:enzymology* / Q000235:genetics; D016923:Cell Death / Q000502:physiology; D002540:Cerebral Cortex / Q000187:drug effects / Q000201:enzymology*; D004195:Disease Models, Animal; D020868:Gene Silencing / Q000502:physiology; D005947:Glucose / Q000172:deficiency; D019194:Ischemic Preconditioning / Q000379:methods*; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / Q000235:genetics / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D016202:N-Methylaspartate / Q000633:toxicity; D009474:Neurons / Q000201:enzymology; D018696:Neuroprotective Agents / Q000378:metabolism*; D010100:Oxygen / Q000494:pharmacology; D061251:Primary Cell Culture; D051744:Protein Kinase C-epsilon / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C491468:Fyb protein, mouse; D018696:Neuroprotective Agents; D034741:RNA, Small Interfering; D016202:N-Methylaspartate; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D051744:Protein Kinase C-epsilon; D005947:Glucose; D010100:Oxygen