Growth arrest DNA damage-inducible protein 45 β (GADD45B) has been reported to be a regulatory factor for active DNA demethylation and is implicated in the modulation of synaptic plasticity and chronic stress-related psychopathological processes. However, its precise role and mechanism of action in stress susceptibility remain elusive. In this study, we found a significant reduction in GADD45B expression specifically in the ventral, but not the dorsal hippocampal CA1 (dCA1) of stress-susceptible mice. Furthermore, we demonstrated that GADD45B negatively regulates susceptibility to social stress and NMDA receptor-dependent long-term potentiation (LTP) in the ventral hippocampal CA1 (vCA1). Importantly, through pharmacological inhibition using the NMDA receptor antagonist MK801, we provided further evidence supporting the hypothesis that GADD45B potentially modulates susceptibility to social stress by influencing NMDA receptor-mediated LTP. Collectively, these results suggested that modulation of NMDA receptor-mediated synaptic plasticity is a pivotal mechanism underlying the regulation of susceptibility to social stress by GADD45B.
Animals ; Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors* ; CA1 Region, Hippocampal/drug effects* ; Male ; Stress, Psychological/physiopathology* ; Mice ; Neuronal Plasticity/drug effects* ; Long-Term Potentiation/drug effects* ; Mice, Inbred C57BL ; Antigens, Differentiation/metabolism* ; Dizocilpine Maleate/pharmacology* ; Excitatory Amino Acid Antagonists/pharmacology* ; GADD45 Proteins

High mobility group box 1 (HMGB1), when released extracellularly, plays a pivotal role in the development of spinal cord synapses and exacerbates autoimmune diseases within the central nervous system. In experimental autoimmune encephalomyelitis (EAE), a condition that models multiple sclerosis, the levels of extracellular HMGB1 and interleukin-33 (IL-33) have been found to be inversely correlated. However, the mechanism by which IL-33 deficiency enhances HMGB1 release during EAE remains elusive. Our study elucidates a potential signaling pathway whereby the absence of IL-33 leads to increased binding of P300/CBP-associated factor with HMGB1 in the nuclei of astrocytes, upregulating HMGB1 acetylation and promoting its release from astrocyte nuclei in the spinal cord of EAE mice. Conversely, the addition of IL-33 counteracts the TNF-α-induced increase in HMGB1 and acetylated HMGB1 levels in primary astrocytes. These findings underscore the potential of IL-33-associated signaling pathways as a therapeutic target for EAE treatment.
Animals ; Encephalomyelitis, Autoimmune, Experimental/metabolism* ; Astrocytes/metabolism* ; Interleukin-33/metabolism* ; HMGB1 Protein/metabolism* ; Acetylation ; Mice, Knockout ; Mice, Inbred C57BL ; p300-CBP Transcription Factors/metabolism* ; Mice ; Spinal Cord/metabolism* ; Cells, Cultured ; Female ; Signal Transduction

Objective To investigate the role and underlying mechanism of atorvastatin on hyper-glycemia induced hemorrhagic transformation(HT)in a mouse model of cerebral ischemia.Meth-ods A total of 36 SPF-grade male C57BL/6 mice were randomly divided into sham operation group,HT model group and atorvastatin group,with 12 mice in each group.HE staining was used to observe cerebral hemorrhage,immunofluorescent staining was employed to detect the integrity of blood-brain barrier,and Western blotting was applied to measure the protein expression of IgG,ZO-1,occludin,claduin5,MMP-2 and-9 in ischemic penumbra brain tissues.Results Com-pared with sham operation group,the neurological deficit score,mortality rate,HT incidence,HT grading score,IgG fluorescence intensity,and protein levels of IgG,MMP-2 and-9 were signifi-cantly increased,while the protein levels of ZO-1,occludin and claudin5 were obviously decreased in the HT model group(P＜0.01).Atorvastatin treatment resulted in significantly lower neuro-logical deficit score(2.73±1.19 vs 3.91±0.94),mortality rate(16.7％vs 41.6％),HT incidence(58.3％vs 91.6％),HT grading score(1.00±1.04 vs 2.58±1.13),IgG fluorescence intensity(504.30±105.52 a.u vs 859.91±153.28 a.u),and protein levels of IgG(4.55±1.40 vs 12.06± 3.73),MMP-2(1.87±0.41 vs 2.95±0.68)and-9(1.47±0.24 vs 2.12±0.23)(P＜0.05,P＜0.01),and increased protein levels of ZO-1(1.55±0.20 vs 0.53±0.10),occludin(0.92±0.11 vs 0.35±0.07)and claudin5(0.58±0.04 vs 0.30±0.05)(P＜0.01)when compared with the HT model group.Conclusion Atorvastatin can reduce the permeability of blood-brain barrier by in-hibiting the activation of MMP-2 and MMP-9 and up-regulating the protein levels of ZO-1,occlu-din and claudin5,and thus attenuate hyperglycemia-induced HT.

Alzheimer Disease/drug therapy* ; Humans

Objective To investigate G protein-coupled estrogen receptor(GPER)mediated neuroprotective effect and mechanism in an ischemic stroke model. Methods Bilateral ovariectomy (OVX)was used to establish a castrated model of adult SPF grade female SD rats. Enzyme-linked immunosorbent assay was used to detect serum estrogen level at 4 weeks after procedure.Middle cerebral artery occlusion(MCAO)was use to prepare a stroke model.The rats were randomly divided into sham operation(n=6),MCAO(n=7),MCAO+estrogen(MCAO+E2,n=8),MCAO+agonist(MCAO+G1,n=8)and MCAO +antagonist G15(MCAO +G15,n =7)groups. The neurological severity score (NSS),2,3,5-triphenyltetrazolium chloride(TTC)staining were used to measure the volume of cerebral infarction in order to assess the effects of different interventions.Western blot was used to detect the protein expression of hypoxia inducible factor-1α(HIF-1α),c-Jun N-terminal kinase(JNK),and Caspase-3 in the ischemic penumbra. Results (1)Estrogen level:after OVX,The level of serum estrogen in rats was significantly lower than that before castration(20 ± 9 ng/L vs. 73 ± 21 ng/L,P <0. 01).(2)NSS score:the NSS score of MCAO in each group was significant higher than that in the sham operation group (P<0.01);The NSS score of the MCAO+G1 group was significantly lower than that of the MCAO group and the MCAO+G15 group(6.0 ±1.8 vs.11.9 ±2.0 and 10.0 ±2.1).The difference was statistically significant (all P<0.05).(3)Cerebral infarct volume:there was significant difference in infarcted volume between the sham operation group and all other groups(all P<0.01);Compared with the MCAO group and the MCAO+G15 group,the infarct volume of the MCAO+E2 group and MCAO+G1 group was significantly reduced(19.8 ± 4.0%,14.0 ± 2.9%)vs.29.7 ± 5.8% and 27.6 ± 3.6%).The difference was statistically significant (all P<0.05).(4)Results of Western blot:the relative optical density values of HIF-1α,JNK,and Caspase-3 of the MCAO group were higher than those of the MCAO + G1 group(all P <0.01). Conclusions GPER mediates the neuroprotective effect of estrogen in the ischemic stroke model.This protective effect is associated with the regulation of the expression levels of HIF-1α,JNK,and Caspase-3.

This study evaluated the correlation between DNA degradation of the splenic lymphocytes and the early time of death, examined the early time of death by computerized image analysis technique (CIAT) and identified the best parameter that quantitatively reflects the DNA degradation.The spleen tissues from 34 SD rats were collected, subjected to cell smearing every 2 h within the first 36 h after death, stained by Feulgen-Van's staining, three indices reflecting DNA content in splenic lymphocytes, including integral optical density (IOD), average optical density (AOD), average gray scale (AG) were measured by the image analysis. Our results showed that IOD and AOD decreased and AG increased over time within the first 36 h. A stepwise linear regression analysis showed that only AG was fitted. A correlation between the postmortem interval (PMI) and AG was identified and the corresponding regression equation was obtained. Our study suggests that CIAT is a useful and promising tool for the estimation of early PMI with good objectivity and reproducibility,and AG is a more effective and better quantitative indicator for the estimation of PMI within the first 36 h after death in rats.

To determining the postmortem interval (PMI) through quantitative analysis of the DNA degradation of cell nucleus in human brain and spleen by using image analysis technique (IAT). The brain and spleen tissues from 32 cadavers with known PMI were collected, subjected to cell smear every 1 h within the first 5-36 h after death, stained by Feulgen-Van's staining, Three indices reflecting DNA in brain cells (astrocytes) and splenic lymphocytes, including integral optical density (IOD), average optical density (AOD), average gray (AG) were measured by employing the mage analysis instrument. The results showed that IOD and AOD declined and AG increased with the prolongation of dead time within 5-36 h. A correlation between the PMI and gray parameters (IOD, AOD and AG) was identified and the corresponding regression equation was obtained. The parameters (IOD, AOD and AG) were proved to be effective quantitative indicators for accurate estimation of PMI within 5-36 h after death.
Cell Nucleus/*pathology ; DNA Degradation, Necrotic ; Forensic Pathology ; Liver/*pathology ; Postmortem Changes ; Spleen/*pathology ; Time Factors

To determining the postmortem interval (PMI) through quantitative analysis of the DNA degradation of cell nucleus in human brain and spleen by using image analysis technique (IAT). The brain and spleen tissues from 32 cadavers with known PMI were collected, subjected to cell smear every 1 h within the first 5-36 h after death, stained by Feulgen-Van's staining, Three indices reflecting DNA in brain cells (astrocytes) and splenic lymphocytes, including integral optical density (IOD), average optical density (AOD), average gray (AG) were measured by employing the mage analysis instrument. The results showed that IOD and AOD declined and AG increased with the prolongation of dead time within 5-36 h. A correlation between the PMI and gray parameters (IOD,AOD and AG) was identified and the corresponding regression equation was obtained. The parameters (IOD,AOD and AG) were proved to be effective quantitative indicators for accurate estimation of PMI within 5-36 h after death.

Objective To study changes of DNA content in human spleen nuclei and seek an experimental method for estimation of the postmortem interval(PMI)using computerized image-analysis technique(CIAT).Methods Smear sections from spleen sampled were collected in 36 cadavers with known the accurate PMI respectively every hour within the first 36 hours after death,which were then fixed with cold Carony fixation.The smeared sections were stained by Feulgen-van's staining method.3 indices for spleen nucleic DNA including integral optical density(IOD),average optical density(AOD)and average gray(AG)were measured using the CIAT.Results IOD and AOD in the spleen nuclei declined regularly,whereas AG increased with the extension of PMIs in 36 hours.Conclusion There are definite relationships between the PMI and gray parameters(IOD、AOD and AG)representing the DAN content of nucleic DNA in the spleen in 36 hours after death,which may be used for estimation of PMI.