title: Effects of SPAK knockout on sensorimotor gating, novelty exploration, and brain area-dependent expressions of NKCC1 and KCC2 in a mouse model of schizophrenia.
abstract: SPAK (Sterile 20/SPS1-related proline/alanine-rich kinase) is a protein kinase belonging to the mitogen-activated protein kinase (MAPK) superfamily that has been found to be extensively distributed across the body. The SPAK downstream substrates NKCC1 and KCC2 in the central nervous system are important in the interpretation of developmental mental disorders. The present study aimed to clarify the role of SPAK-NKCC1/KCC2 using a rodent schizophrenia-like model. The mouse paradigm of isolation rearing (IR) was employed, as it simulates the sensorimotor gating abnormalities of schizophrenia. SPAK transgenic mice were used and were divided into four groups: social-wild type, social-SPAK(-/-), isolation-wild type, and isolation-SPAK(-/-). The prepulse inhibition (PPI) test and the novel object recognition test (NORT) were used to measure schizophrenia-associated dysfunctions in gating ability and the novelty recognition, respectively. Finally, the protein expressions of NKCC1/KCC2 in the prefrontal cortex and hippocampus were detected to determine correlations with the behavioral data. Our results demonstrated that SPAK-null mice had superior PPI and novelty recognition relative to wild type controls, with a concomitant increase in KCC2 in the prefrontal cortex. IR disrupted PPI and NORT performances with an associated increase in KCC2. Furthermore, rearing environment and gene manipulation had mutually interactive effects, as the IR-induced effects on PPI and NORT were reversed by SPAK knockout, and the increase in KCC2 and the decreased in the NKCC1/KCC2 ratio in the prefrontal cortex induced by SPAK knockout were reversed by IR. Our data supported the gene-environment hypothesis and demonstrated the potential value of SPAK manipulation in future schizophrenia studies.
authors: Department of Nephrology, Tri-Service General Hospital, Taipei, Taiwan; Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan.
authors: Sung-Sen
authors: SS
authors: Yang
authors: Medical Research Center, Cardinal Tien Hospital, New Taipei City, Taiwan; Department of Physiology and Biophysics, National Defense Medical Center, Taipei, Taiwan.
authors: Chuen-Lin
authors: CL
authors: Huang
authors: Department of Physiology and Biophysics, National Defense Medical Center, Taipei, Taiwan.
authors: Huei-E
authors: HE
authors: Chen
authors: Department of Physiology and Biophysics, National Defense Medical Center, Taipei, Taiwan; Division of Medical Research and Education, Cheng Hsin General Hospital, Taipei, Taiwan.
authors: Che-Se
authors: CS
authors: Tung
authors: Department of Physiology and Biophysics, National Defense Medical Center, Taipei, Taiwan.
authors: Han-Peng
authors: HP
authors: Shih
authors: Department of Physiology and Biophysics, National Defense Medical Center, Taipei, Taiwan; Department of Psychiatry, Tri-Service General Hospital, Taipei, Taiwan. Electronic address: yiaping@ndmctsgh.edu.tw.
authors: Yia-Ping
authors: YP
authors: Liu
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D004195:Disease Models, Animal; D005106:Exploratory Behavior / Q000502:physiology*; D005786:Gene Expression Regulation / Q000235:genetics; D005838:Genotype; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009043:Motor Activity / Q000235:genetics; D065808:Prepulse Inhibition / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000172:deficiency* / Q000235:genetics; D012559:Schizophrenia / Q000150:complications / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D055139:Sensory Gating / Q000235:genetics*; D064466:Solute Carrier Family 12, Member 1 / Q000378:metabolism*; D064506:Solute Carrier Family 12, Member 2 / Q000378:metabolism*
chemical_list: D064466:Solute Carrier Family 12, Member 1; D064506:Solute Carrier Family 12, Member 2; C486407:Stk39 protein, mouse; D017346:Protein Serine-Threonine Kinases
keywords: NKCC(1)/KCC(2); Novelty recognition; Prepulse inhibition; Rearing environment; SPAK knockout