title: DLK silencing attenuated neuron apoptosis through JIP3/MA2K7/JNK pathway in early brain injury after SAH in rats.
abstract: OBJECTIVE
  Dual leucine zipper kinase (DLK/MA3K12) has been reported involved in apoptosis and neuronal degeneration during neural development and traumatic brain injury. This study was designed to investigate the role of DLK with its adaptor protein JNK interacting protein-3 (JIP3), and its downstream MA2K7/JNK signaling pathway in early brain injury (EBI) after subarachnoid hemorrhage (SAH) in a rat model.
  
  
  METHODS
  Controlled in vivo laboratory study.
  
  
  METHODS
  Animal research laboratory.
  
  
  METHODS
  Two hundred and twenty-three adult male Sprague-Dawley rats weighing 280-320g.
  
  
  METHODS
  SAH was induced by endovascular perforation in rats. The SAH grade, neurological score, and brain water content were measured at 24 and 72h after SAH. Immunofluorescence staining was used to detect the cells that expressed DLK. The terminal deoxynucleotid transferase-deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL) was used to detect the neuronal apoptosis. In mechanism research, the expression of DLK, JIP3, phosphorylated-JNK (p-JNK)/JNK, and cleaved caspase-3 (CC-3) were analyzed by western blot at 24h after SAH. The DLK small interfering RNA (siRNA), JIP3 siRNA, MA2K7 siRNA and recombinant DLK protein which injected intracerebroventricularly were given as the interventions.
  
  
  RESULTS
  The DLK expression was increased in the left cortex neurons and peaked at 24h after SAH. DLK siRNA attenuated brain edema, reduced neuronal apoptosis, and improved the neurobehavioral functions after SAH, but the recombinant DLK protein deteriorated neurobehavioral functions and brain edema. DLK siRNA decreased and recombinant DLK protein increased the expression of MA2K7/p-JNK/CC-3 at 24h after SAH. The JIP3 siRNA reduced the level of JIP3/MA2K7/p-JNK/CC-3, combined DLK siRNA and JIP3 siRNA further decreased the expression of DLK/MA2K7/p-JNK/CC-3, and MA2K7 siRNA lowered the amount of MA2K7/p-JNK/CC-3 at 24h after SAH.
  
  
  CONCLUSIONS
  As a negative role, DLK was involved in EBI after SAH, possibly mediated by its adaptor protein JIP3 and MA2K7/JNK signaling pathways. To reduce the level of DLK may be a new target as intervention for SAH.
authors.affiliation: Departments of Anesthesiology and Physiology, Loma Linda University School of Medicine, Loma Linda, CA, USA; Department of Neurosurgery, Affiliated Hospital of the University of Electronic Science and Technology of China, Sichuan Provincial People's Hospital, Chengdu, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Yin
authors.affiliation: Department of Neurosurgery, Affiliated Hospital of the University of Electronic Science and Technology of China, Sichuan Provincial People's Hospital, Chengdu, China.
authors.forename: Guang-Fu
authors.initials: GF
authors.lastname: Huang
authors.affiliation: Department of Neurosurgery, First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
authors.forename: Xiao-Chuan
authors.initials: XC
authors.lastname: Sun
authors.affiliation: Department of Neurosurgery, First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
authors.forename: Zongduo
authors.initials: Z
authors.lastname: Guo
authors.affiliation: Departments of Anesthesiology and Physiology, Loma Linda University School of Medicine, Loma Linda, CA, USA. Electronic address: jhzhang@llu.edu.
authors.forename: John H
authors.initials: JH
authors.lastname: Zhang
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000096:biosynthesis* / Q000235:genetics; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D001930:Brain Injuries / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D020868:Gene Silencing / Q000502:physiology*; D020930:MAP Kinase Kinase Kinases / Q000096:biosynthesis* / Q000235:genetics; D020935:MAP Kinase Signaling System / Q000502:physiology*; D008297:Male; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000235:genetics; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013345:Subarachnoid Hemorrhage / Q000235:genetics / Q000378:metabolism* / Q000473:pathology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D009419:Nerve Tissue Proteins; C554781:mapk8ip3 protein, rat; D020930:MAP Kinase Kinase Kinases; C090757:mitogen-activated protein kinase kinase kinase 12
keywords: Apoptosis; DLK; Early brain injury; Neuron; Subarachnoid hemorrhage