Increased phosphorylation of CaMK Ⅱ in cerebral tissues from hypoxially preconditioned mice / 基础医学与临床

Objective To explore the role of calcium/calmodulin-dependent protein kinase Ⅱ ( CaMK Ⅱ ) in the development of cerebral hypoxic preconditioning(HPC). Methods Healthy male BALB/c mice were randomly divided into 7 groups as follows; normoxic control (H0) , early(H1～H4) and delayed (H5～H6) hypoxically preconditioned mice groups. SDS-PAGE, Western blot and Gel Doc imagine systems were applied to quantitatively analyze the level of CaMK Ⅱ phosphorylation and protein expression level in the brain of mice. Results Compared with H0 group, the phosphorylation level of CaMK Ⅱ increased in cortex and hippocampus of mice in H3～H5 hypoxically preconditioned groups (P<0.05). However, there was no significant changes in total CaMK Ⅱ protein expression in cortex and hippocampus of hypoxic preconditioned mice. Similarly, enhanced p-Thr286 CaMK Ⅱ was also observed in the hippocampus and cortex of mice by immunostaining following hypoxic exposures (H3 and H6). Conclusion The increased phosphorylation of CaMKⅡ may be involved in the development of cerebral HPC in mice.

Identification of nPKCε-interacted proteins in the cortex of hypoxic preconditioned mice / 基础医学与临床

Objective Identify novel protein kinase Cε(nPKCε)-interacted proteins in the cortex of hypoxic preconditioned mice.Methods Immunoprecipitation (IP) and two-dimensional electrophoresis (2-DE) combining with ImageMaster 2D Platinum software were applied to analyze the differential expressions of nPKCe-interacted proteins;the target protein spots were identified by matrix-associated laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) and Western blot.Results Compared with control group,there were 34 upregulated protein spots and 20 downregulated protein spots in cytosolic fraction,while 27 upregulated prtein spots and 28 downregulated protein spots were determined in particulate fraction of cerebral cortex of HPC mice.The levels of nPKCε-interacted HSP 70 and 14-3-3γ/protein expressions increased significantly in both cytosolic and particulate fractions;but the protein level of nPKCε-interacted HSP60 increased only in particulate fraction of cerebral cortex of HPC mice.Conclusion nPKCε might be involved in the development of cerebral HPC via the regulation of its interacted proteins such as HSP60,HSP70 and 14-3-3γ.

CRMP-2 is involved in hypoxic preconditioning-induced neuroprotection against cerebral ischemic injuries of mice / 基础医学与临床

Objective To investigate whether conventional protein kinase C (cPKC ) βⅡ-interacting collapsin response mediator protein-2 (CRMP-2) provides neuroprotection against cerebral ischemic (I) injuries. Methods Male BALB/c mice were randomly divided into normoxic control (Nor) , HPC, Nor + Sham, HPC + Sham, Nor + I and HPC + I groups (n = 6 per group). Using our HPC and MCAO mouse models, we applied immunoprecipita-tion, two-dimensional electrophoresis and mass spectrometry to characterize cPKCβⅡ-interacting proteins and combined with SDS-PAGE and Western blot to quantitatively analyze CRMP-2 phosphorylation and degradation levels in the brain of mice after HPC and MCAO. Results The expression level of 10 cPKCβⅡ-interacting proteins changed obviously in cerebral cortex of HPC mice when compared with Nor group. One of these proteins, CRMP-2 protein level increased in particulate fraction and decreased in cytosolic fraction of cerebral cortex of HPC mice. CRMP-2 phosphorylation level in ischemic core (Ic) of cerebral cortex decreased significantly ( P < 0. 05 , n = 6) as compared with that of Nor + sham group, but CRMP-2 phosphorylation level in HPC +I group increased significantly as compared with that of Nor +I group ( P < 0. 05, n = 6). In ischemic cortex, CRMP-2 degradation (proteolysis) was observed as the appearance of 55 ku breakdown products (BDP). However, the CRMP-2 degradation level, BDPs products decreased significantly in penumbra ( P) of ischemic cortex from HPC +I group when we compared with that of Nor +I group (P < 0. 05, n = 6 ). Conclusion CRMP-2 is involved in attenuating the decrease of CRMP-2 phosphorylation in ischemic core and in inhibiting its degradation in penumbra of cerebral cortex of mice thereby to lessen the ischemic injuries.

Increased phosphorylation of P38 MAPK in cerebral tissues of hypoxic preconditioned mice / 基础医学与临床

Objective To explore the role of P38 mitogen-activated protein kinase (P38 MAPK) in the development of cerebral hypoxic preconditioning. Methods Healthy male BALB/C mice weighted as18～20 g were randomly divided into 7 groups as follows: normoxic control (H0), early (H1～H4) and delayed (H5 and H6) hypoxic preconditioned mice groups. SDS-PAGE, Western blot and Gel Doc imagine systems were applied to quantitatively analyze the level of P38 MAPK phosphorylation and protein expression in the brain of mice. Results The phosphorylation levels of P38 MAPK increased in cortex, hippocampus and hypothalamus of mice in both early (H1～H4) and delayed (H5 and H6) hypoxic preconditioned groups, and the statistic significance (P