Expression In Cerebral Cortex Research Articles

Epigallocatechin gallate improves neuronal damage in animal model of ischemic stroke and glutamate-exposed neurons via modulation of hippocalcin expression.

Epigallocatechin gallate (EGCG) is a polyphenolic component of green tea that has anti-oxidative and anti-inflammatory effects in neurons. Ischemic stroke is a major neurological disease that causes irreversible brain disorders. It increases the intracellular calcium concentration and induces apoptosis. The regulation of intracellular calcium concentration is important to maintain the function of the nervous system. Hippocalcin is a neuronal calcium sensor protein that controls intracellular calcium concentration. We investigated whether EGCG treatment regulates the expression of hippocalcin in stroke animal model and glutamate-induced neuronal damage. We performed middle cerebral artery occlusion (MCAO) to induce cerebral ischemia. EGCG (50 mg/kg) or phosphate buffered saline was injected into the abdominal cavity just before MCAO surgery. The neurobehavioral tests were performed 24 h after MCAO surgery and cerebral cortex tissue was collected. MCAO damage induced severe neurobehavioral disorders, increased infarct volume, and decreased the expression of hippocalcin in the cerebral cortex. However, EGCG treatment improved these deficits and alleviated the decrease in hippocalcin expression in cerebral cortex. In addition, EGCG dose-dependently alleviated neuronal cell death and intracellular calcium overload in glutamate-exposed neurons. Glutamate exposure reduced hippocalcin expression, decreased Bcl-2 expression, and increased Bax expression. However, EGCG treatment mitigated these changes caused by glutamate toxicity. EGCG also attenuated the increase in caspase-3 and cleaved caspase-3 expressions caused by glutamate exposure. The effect of EGCG was more pronounced in non-transfected cells than in hippocalcin siRNA-transfected cells. These findings demonstrate that EGCG protects neurons against glutamate toxicity through the regulation of Bcl-2 family proteins and caspase-3. It is known that hippocalcin exerts anti-apoptotic effect through the modulation of apoptotic pathway. Thus, we can suggest evidence that EGCG has a neuroprotective effect by regulating hippocalcin expression in ischemic brain damage and glutamate-exposed cells.

Role of caspase-8 in stem cell transplantation alleviates rat cerebral cortex apoptosis after cardiopulmonary resuscitation

To explore the effects and the possible mechanism of bone marrow mesenchymal stem cell (BMMSC) transplantation on apoptosis in rats cerebral cortex after cardiac arrest/cardiopulmonary resuscitation (CA/CPR). The BMMSC of 2 Sprague-Dawley (SD) rats aged 4-5weeks was extracted, and the 3rd passage was used in experimental study. Eighteen Sprague-Dawley (SD) rats were divided into sham group, model group (CA/CPR group) and intervention group (BMMSC group) according to random number table method, with 6 rats in each group. CPR was performed 6 minutes after asphyxia induced CA. In sham group, CA was not induced except performing general surgical procedure. At 1 hour after return of spontaneous circulation (ROSC), 0.5 mL phosphate buffered saline (PBS) was injected through tail vein in CA/CPR group. 2×109/L green fluorescence protein (GFP)-labeled BMMSC was injected through tail vein 1 hour after ROSC in BMMSC group. Neurological deficit score (NDS) were assessed in every group at 72 hours after CPR. Serum S100 calcium binding protein B (S100B) levels were assayed by enzyme linked immunosorbent assay (ELISA). Distribution of BMMSC in brain was observed under a fluorescent microscope. Apoptosis rate in cerebral cortex was assayed by TdT-mediated dUTP nick-end labeling (TUNEL). Western blotting was performed to measure the expression levels of active aspartic acid specific cysteine proteinase (caspase-8 and caspase-9) in cerebral cortex. At 3 days after CPR, compared with sham group, the apoptosis of cerebral cortex cells was increased and brain damage was obvious, NDS score was decreased significantly (56.6±5.5 vs. 80.0±0.0, P < 0.05), and serum S100B was increased markedly (ng/L: 45.1±4.7 vs. 19.1±1.4, P < 0.05), apoptosis rate of cerebral cortex cells increased significantly [(52.9±11.8)% vs. (10.1±1.5)%, P < 0.05], the level of active caspase-8 expression in cerebral cortex was significantly higher (caspase-8/GAPDH: 0.689±0.047 vs. 0.330±0.108, P < 0.05), and there was no significant difference in active caspase-9 protein expression (caspase-9/GAPDH: 0.428±0.014 vs. 0.426±0.021, P > 0.05) in CA/CPR group. After BMMSC transplantation, GFP-labeled BMMSC were primarily detected in cerebral cortex, compared with CA/CPR group, the apoptosis of cerebral cortex cells and brain injury were significantly improved in BMMSC group, NDS score increased significantly (70.6±2.1 vs. 56.6±5.5, P < 0.05), serum S100B levels in BMMSC group were lower (ng/L: 32.0±3.2 vs. 45.1±4.7, P < 0.05), apoptosis rate of cerebral cortex cells decreased significantly [(31.1±3.4)% vs. (52.9±11.8)%, P < 0.05], and the active caspase-8 expression in cerebral cortex in BMMSC group was significantly decreased (caspase-8/GAPDH: 0.427±0.067 vs. 0.689±0.047, P < 0.05). The active caspase-9 expression in cerebral cortex in BMMSC group and CA/CPR group were not significantly different (caspase-9/GAPDH: 0.431±0.022 vs. 0.428±0.014, P > 0.05). BMMSC transplantation can alleviate rat brain damage after CA/CPR possibly by inhibiting the death receptor mediated apoptotic pathway to inhibit the apoptosis of brain cells.

Transcriptome and Translatome Regulation of Pathogenesis in Alzheimer's Disease Model Mice

AbstractBackgroundDefining cellular mechanisms that drive Alzheimer's disease (AD) pathogenesis and progression will be aided by studies defining how gene expression patterns change during pre‐symptomatic AD and ensuing periods of declining cognition. Previous studies have emphasized changes in transcriptome, but not translatome regulation, leaving the ultimate results of gene expression alterations relatively unexplored in the context of AD.MethodTo identify genes whose expression might be regulated at the transcriptome and translatome levels in AD, we analyzed gene expression in cerebral cortex of two AD model mouse strains, CVN (APPSwDI;NOS2‐/‐) and Tg2576 (APPSw), and their companion wild type (WT) strains at 6 months of age by tandem RNA‐Seq and Ribo‐Seq (ribosome profiling). Identical starting pools of bulk RNA were used for RNA‐Seq and Ribo‐Seq. Differential gene expression analysis was performed at the transcriptome, translatome, and translational efficiency levels to disentangle genes specifically regulated at the translation level. Regulated genes were functionally evaluated by gene ontology tools.ResultCompared to WT mice, AD model mice had similar levels of transcriptome regulation, but differences in translatome regulation. A microglial signature associated with early stages of Aβ accumulation was upregulated at both levels in CVN mice. Although the two mice strains did not share many regulated genes, they showed common regulated pathways related to APP metabolism associated with neurotoxicity and neuroprotection.ConclusionThis work represents the first genome‐wide study of brain translatome regulation in animal models of AD, and provides evidence of a tight and early translatome regulation of gene expression controlling the balance between neuroprotective and neurodegenerative processes in brain.

Drp1 activates ROS/HIF-1α/EZH2 and triggers mitochondrial fragmentation to deteriorate hypercalcemia-associated neuronal injury in mouse model of chronic kidney disease

BackgroundChronic kidney disease (CKD), characterized as renal dysfunction, is regarded as a major public health problem which carries a high risk of cardiovascular diseases. The purpose of this study is to evaluate the functional significance of Drp1 in hypercalcemia-associated neuronal damage following CKD and the associated mechanism.MethodsInitially, the CKD mouse models were established. Next, RT-qPCR and Western blot analysis were performed to measure expression of Fis1 and Drp1 in CKD. Chromatin immunoprecipitation (ChIP) assay and dual-luciferase reporter gene assay were utilized to explore the relationship among Drp1, HIF-1α, EZH2, and ROS with primary cortical neurons isolated from neonatal mice. Next, CKD mice were subjected to calcitonin treatment or manipulation with adenovirus expressing sh-Drp1, so as to explore the effects of Drp1 on hypercalcemia-induced neuronal injury in CKD. TUNEL assay and immunofluorescence staining were performed to detect apoptosis and NeuN-positive cells (neurons) in prefrontal cortical tissues of CKD mice.ResultsIt was found that hypercalcemia could induce neuronal injury in CKD mice. An increase of Fis1 and Drp1 expression in cerebral cortex of CKD mice correlated with mitochondrial fragmentation. Calcitonin suppressed Drp1/Fis1-mediated mitochondrial fragmentation to attenuate hypercalcemia-induced neuronal injury after CKD. Additionally, Drp1 could increase EZH2 expression through the binding of HIF-1α to EZH2 promoter via elevating ROS generation. Furthermore, Drp1 knockdown inhibited hypercalcemia-induced neuronal injury in CKD while overexpression of EZH2 could reverse this effect in vivo.ConclusionTaken together, the key findings of the current study demonstrate the promotive role of Drp1 in mitochondrial fragmentation which contributes to hypercalcemia-induced neuronal injury in CKD.

Transcriptome and Translatome Regulation of Pathogenesis in Alzheimer’s Disease Model Mice

Background: Defining cellular mechanisms that drive Alzheimer’s disease (AD) pathogenesis and progression will be aided by studies defining how gene expression patterns change during pre-symptomatic AD and ensuing periods of declining cognition. Previous studies have emphasized changes in transcriptome, but not translatome regulation, leaving the ultimate results of gene expression alterations relatively unexplored in the context of AD. Objective: To identify genes whose expression might be regulated at the transcriptome and translatome levels in AD, we analyzed gene expression in cerebral cortex of two AD model mouse strains, CVN (APPSwDI;NOS2 -/- ) and Tg2576 (APPSw), and their companion wild type (WT) strains at 6 months of age by tandem RNA-Seq and Ribo-Seq (ribosome profiling). Methods: Identical starting pools of bulk RNA were used for RNA-Seq and Ribo-Seq. Differential gene expression analysis was performed at the transcriptome, translatome, and translational efficiency levels. Regulated genes were functionally evaluated by gene ontology tools. Results: Compared to WT mice, AD model mice had similar levels of transcriptome regulation, but differences in translatome regulation. A microglial signature associated with early stages of Aβ accumulation was upregulated at both levels in CVN mice. Although the two mice strains did not share many regulated genes, they showed common regulated pathways related to AβPP metabolism associated with neurotoxicity and neuroprotection. Conclusion: This work represents the first genome-wide study of brain translatome regulation in animal models of AD and provides evidence of a tight and early translatome regulation of gene expression controlling the balance between neuroprotective and neurodegenerative processes in brain.

Astaxanthin ameliorates damage to the cerebral cortex, hippocampus and cerebellar cortex caused by methotrexate

ABSTRACT We investigated the ameliorating effects of astaxanthin (AXA) on methotrexate (MTX) induced damage to the cerebral cortex, hippocampus, cerebellar cortex and blood. We used 24 female Wistar albino rats divided into three groups of eight as follows: sham/control group, single dose of saline intraperitoneally (i.p.) and 7 days orally; MTX group, single dose of 20 mg/kg MTX (i.p.); MTX + AXA group, single dose of 20 mg/kg MTX i.p.+ 100 mg/kg AXA orally for 7 days. For all groups we measured total oxidant status (TOS) and total antioxidant status (TAS) in the cerebral cortex, hippocampus and blood. Histological sections of cerebral cortex, hippocampus and cerebellar cortex were inspected microscopically. Caspase-3 (cas-3), granulocyte colony-stimulating factor (GCSF), growth related oncogene (GRO), inducible nitric oxide synthase (iNOS) and myelin basic protein (MBP) were estimated immunohistochemically in the cerebral cortex, hippocampus and cerebellar cortex. In the MTX group, TAS was decreased significantly in the cerebral cortex, hippocampus and blood, while TOS was significantly increased. AXA significantly ameliorated oxidative stress parameters in the cerebral cortex and hippocampus. Histopathological examination revealed degeneration, edema and hyperemia in the cerebral cortex, hippocampus and cerebellar cortex in the MTX group. AXA treatment ameliorated histopathological changes. MTX decreased MBP expression in cerebral cortex. Although MBP expression was decreased in the cerebral cortex, hippocampus and cerebellar cortex stimulated with MTX, the expressions of cas-3, GCSF, GRO and iNOS were significantly increased. AXA ameliorated the expression of cas-3, GCSF, GRO, iNOS and MBP. AXA exhibits anti-inflammatory, antioxidant and anti-apoptotic effects on MTX induced toxicity in the cerebral cortex, hippocampus and cerebellar cortex by increasing MBP expression, regulating inflammatory cytokine release and reducing oxidative stress.

High Dietary Iron Has a Greater Impact on Brain Iron Homeostasis and Cognitive Function in Old Compared with Young C57BL/6J Male Mice

BackgroundBrain iron accumulation is a feature of Alzheimer disease (AD) but whether a chronic dietary iron overload contributes to AD induction is unknown. We previously showed that young mice fed a high iron diet did not display cognitive impairment despite the AD pathological markers in hippocampus. ObjectivesWe aim to compare the impact of high dietary iron on brain pathologic changes and cognitive function in young and old mice. MethodsMale C57BL/6J mice at 1 mo and 13 mo of age were fed with either a control diet (66 mg Fe/kg; Young-Ctrl and Old-Ctrl) or a high iron diet (14 g Fe/kg; Young-High Fe and Old-High Fe) for 7 mo, and outcomes were evaluated at 8 mo and 20 mo of age. Iron concentrations in brain regions were measured by atomic absorption spectrophotometry. Perls's Prussian blue staining and amyloid-β (Aβ) immunostaining were performed. Protein expression in the cerebral cortex and hippocampus was determined by immunoblotting. Superoxide dismutase activity and malondialdehyde concentration were examined. Cognitive functions were tested with the Morris water maze system. Two-factor ANOVA was used to analyze most data. ResultsCompared with Old-Ctrl mice, Old-High Fe mice showed significantly higher iron concentrations in cerebral cortex (60% higher), cerebellum (60% higher), and hippocampus (90% higher), paralleled by lower superoxide dismutase activity and greater malondialdehyde concentration in cerebral cortex and hippocampus and worse cognitive function. In contrast, these variables did not significantly differ between the 2 young groups. Nevertheless, ferritin, phospho-tau, and Aβ1–42 expression in hippocampus and ferritin and Aβ1–42 expression in cerebral cortex were induced by the high iron diet irrespective of the age of mice (40–200% greater). ConclusionsHigh dietary iron induced cognitive defects in old mice but not young mice, suggesting that elderly people should avoid consuming abnormally high concentrations of iron.

Novel insights into the pathogenesis of DYT1 dystonia from induced patient-derived neurons.

Novel insights into the pathogenesis of DYT1 dystonia from induced patient-derived neurons.

Geniposidic Acid Confers Neuroprotective Effects in a Mouse Model of Alzheimer's Disease through Activation of a PI3K/AKT/GAP43 Regulatory Axis.

Alzheimer's disease (AD) is a major cause of dementia, which is a growing global health problem and has a huge impact on individuals and society. As the modifying role of geniposidic acid (GPA) has been suggested in AD, this study sets out to determine if and how GPA treatment affects AD progression in mice. Potential downstream target genes of GPA during AD were identified by bioinformatics analysis, revealing GAP43 as a primary candidate protein. Then, mPrP-APPswe/PS1De9 AD transgenic mice were treated with GPA via intragastric administration. This allowed for gain- and loss-of-function assays of candidate proteins being carried out with or without GPA treatment, after which behavioral tests could be conducted for mice. Cortical neuron apoptosis was measured by TUNEL staining, Amyloid β-protein (Aβ) expression in cerebral cortex by Thioflavin-s staining, and Aβ, IL-1β, IL-6, IL-4 and TNF-α levels in cerebral cortex by ELISA. GAP43 expression in cerebral cortex of mice was detected by immunohistochemistry. Primary cortical neurons of embryonic mice were isolated and induced by Aβ1-42 to construct AD cell model. Cell viability was assessed by CCK-8, and axon growth by immunofluorescence. GPA administration significantly improved the cognitive impairment, reducing Aβ accumulation and neuronal apoptosis in AD mice, and alleviated inflammation and axonal injury of Aβ1-42-induced neurons. GAP43 was shown experimentally to be the target of GPA in AD. Silencing of GAP43 repressed the neuroprotective effect of GPA treatment on AD mice. GPA elevated GAP43 expression via PI3K/AKT pathway activation and ultimately improved nerve injury in AD mice. GPA activates a PI3K/AKT/GAP43 regulatory axis to alleviate AD progression in mice.

Necroptosis specific inhibitor-1 inhibits necroptosis in rat brain and improves brain injury after cardiac arrest

To explore the effects of necroptosis specific inhibitor-1 (Nec-1) on brain injury in rats after cardiac arrest and its mechanism. A total of 24 Sprague-Dawley (SD) rats were divided into Sham group, model group and Nec-1 group (n = 8 per group) according to random number table method. In the Sham group, only general surgical procedures were underdone without inducing cardiac arrest. In the model group, the rats were subjected to asphyxial cardiac arrest followed by cardiopulmonary resuscitation (CPR) at 6 minutes after cardiac arrest. In the Nec-1 group, Nec-1 of 1 mg/kg was administered after cardiac arrest, and CPR was performed at 6 minutes after cardiac arrest. At 72 hours after CPR, neurological deficit scores (NDS) were assessed, serum S100B levels were measured by enzyme linked immunosorbent assay (ELISA), receptor-interacting protein 3 (RIP3) expression in cerebral cortex and hippocampus was observed under immunofluorescence and positive rate was calculated, and the levels of RIP3 protein expression in brain were analyzed by Western blotting. At 72 hours after CPR, the rats in the model group showed obvious necroptosis and injury in brain. Compared with the Sham group, the NDS scores in the model group were significantly decreased [57.0 (52.7, 60.0) vs. 80.0 (80.0, 80.0), P < 0.05], the serum S100B was significantly increased (ng/L: 44.9±4.5 vs. 18.6±1.5, P < 0.05), the percentages of RIP3 positive cells in cerebral cortex and hippocampus were significantly elevated [cerebral cortex: (31.7±4.8)% vs. (11.6±3.2)%, hippocampus: (28.4±0.8)% vs. (10.9±0.6)%, both P < 0.05], and the levels of RIP3 protein expression in brain were significantly increased [RIP3 protein (RIP3/GAPDH): 0.708 (0.642, 0.722) vs. 0.408 (0.253, 0.504), P < 0.05]. After Nec-1 intervention, necroptosis and injury in brain were obviously improved. Compared with the model group, the NDS scores at 72 hours after CPR in the Nec-1 group were significantly increased [70.5 (68.5, 71.7) vs. 57.0 (52.7, 60.0), P < 0.05), the serum S100B was significantly decreased (ng/L: 31.9±2.7 vs. 44.9±4.5, P < 0.05), the percentages of RIP3 positive cells in cerebral cortex and hippocampus were significantly lowered [cerebral cortex: (23.7±4.1)% vs. (31.7±4.8)%,hippocampus: (20.4±0.4)% vs. (28.4±0.8)%, both P < 0.05], and the levels of RIP3 protein expression in brain were significantly declined [RIP3 protein (RIP3/GAPDH): 0.437 (0.379, 0.507) vs. 0.708 (0.642, 0.722), P < 0.05]. Nec-1 attenuated necroptosis of brain cells by inhibiting the expression of RIP3 protein, so as to reduce brain injury after cardiac arrest in rats.

Effect of Artesunate vs Memantine in Aluminum Chloride Induced Model of Neurotoxicity in Rats

Alzheimer disease is one of the commonest neurological diseases which is characterized by amyloid plaques accumulation in multiple brain regions. This study investigated the potential neuroprotective effect of artesunate on aluminum induced neurotoxicity vs memantine in rats. 40 male albino Wistar rats were divided randomly into 4 groups as follow: Group 1 negative control, group 2 positive control group induced by ammonium chloride, group 3 rats treated by NH4Cl + artesunate solution, group 4 rats treated by NH4Cl + memantine S.C. spatial Memory and Learning were evaluated using Morris Water Maze (MWM) test. Malondialdehyde (MDA) and reduced glutathione (GSH) levels were measured in cerebral cortex tissue homogenate. Tumor necrosis factor-α (TNFα) and interleukin-1 beta (IL-1β) concentrations were measured in rat cerebral cortex tissue homogenate using rat enzyme linked immunosorbent assay (ELISA) kits. Real-time quantitative reverse transcription-polymerase chain reaction (Real-time qRT-PCR) for Caspase-3, Bcl-2 and iNOS gene expression was measured in rat cerebral cortex. Slices from cerebral cortex were studied by histopathological examination. Artesunate significantly decreased MDA level and inhibited iNOS, caspase and upregulated Bcl-2 gene expression in cerebral cortex. ART increased significantly antioxidant level GSH, and decreased significantly TNF-alpha and IL-B levels. It reduced significantly 1ry retention latency, 2ry retention latency and initial acquisition latency. It also improved brain histopathology and decreased amyloid plaque deposition. ART exerted neuroprotective effect through oxidative stress correction and enhancement of antiapoptotic markers in neuronal cells of the cerebral cortex.

LncRNA Lethe protects sepsis-induced brain injury via regulating autophagy of cortical neurons.

To investigate the role of long non-coding RNA (lncRNA) Lethe in mediating autophagy of cortical neurons in mice with sepsis-induced brain injury (SIBI). A total of 60 wild-type C57BL/6 mice were divided into sham-operated wild-type (SWT) group and wild-type model (MWT) group. Sixty Lethe-/- mice were divided into sham-operated knockout (SKO) group and model knockout (MKO) group. Each group had 30 mice. Sepsis model in mice was established by cecal ligation and puncture (CLP). Neurobiological score was recorded at 6 h after CLP. Mice with lower than 6 scores of neurobehavioral tests were diagnosed with SIBI. Quantitative Real-time polymerase chain reaction (qRT-PCR) was performed to determine mRNA levels of Lethe and interferon-γ (INF-γ) in cortical neurons of SIBI mice. Western blot was conducted to detect protein levels of LC3-II, LC3-I and SQSTM1 in mice. Neuronal impairment in mouse brain was evaluated by hematoxylin and eosin (HE) staining. Expressions of LC3-I and LC3-II in cerebral cortex of MWT group began to increase at 6 h after CLP, and remained at high levels until 96 h. On the contrary, SQSTM1 expression in cerebral cortex of MWT group began to decrease at 6 h after CLP. Compared with SWT group, expressions of Lethe and IFN-γ were remarkably upregulated in cortex of MWT group at 12 h after CLP. Expression of LC3-II in MWT group was remarkably upregulated, while SQSTM1 was downregulated at 12 h after CLP, which were contrary to those in MKO group. At 12 h after CLP, the neurobiological scores of the MKO group (4.97±0.71) were markedly lower than those of the MWT group (5.43±0.86). HE staining showed worse damage in cerebral cortex and fewer neurons of MKO group relative to MWT group. Lethe has a protective effect on SIBI mice by regulating autophagy in mouse cortical neurons.

Female rats are more vulnerable to lasting cognitive impairment after isoflurane exposure on postnatal day 4 than 7

BackgroundThe factors determining peak susceptibility of the developing brain to anaesthetics are unclear. It is unknown why postnatal day 7 (P7) male rats are more vulnerable to anaesthesia-induced memory deficits than littermate females. Given the precocious development of certain regions in the female brain during the neonatal critical period, we hypothesised that females are susceptible to anaesthetic brain injury at an earlier time point than previously tested. MethodsFemale rats were exposed to isoflurane (Iso) 1 minimum alveolar concentration or sham anaesthesia at P4 or P7. Starting at P35, rats underwent a series of behavioural tasks to test their spatial and recognition memory. Cell death immediately after anaesthesia was quantified by Fluoro-Jade C staining in select brain regions, and developmental expression of the chloride transporters KCC2 and NKCC1 was analysed by immunoblotting in male and female rats at P4 and P7. ResultsFemale rats exposed to Iso at P4 displayed impaired spatial, object-place, -context, and social recognition memory, and increased cell death in the hippocampus and laterodorsal thalamus. Female rats exposed at P7 exhibited only decreased performance in object-context compared with control. The ratio of NKCC1/KCC2 expression in cerebral cortex was higher in P4 females than in P7 females, and similar to that in P7 males. ConclusionsFemale rats exposed to Iso at P4 are sensitive to anaesthetic injury historically observed in P7 males. This is consistent with a comparably immature developmental state in P4 females and P7 males. The window of anaesthetic vulnerability correlates with sex-specific cortical expression of chloride transporters NKCC1 and KCC2. These findings suggest that both sex and developmental age play important roles in determining the outcome after early anaesthesia exposure.

Effect of Baicalin on the expression of connexin 36 in the cerebral cortex and striatum area of Parkinson's disease model rat

Objective: To investigate the effect of Baicalin on the expression of connexin 36 (Cx36) in cerebral cortex and striatum area of 6-OHDA-induced Parkinson's (PD) model rats and its significance. Methods: Male Sprague-Dawley (SD) rats were randomly divided into 6 groups, 12 in each group: normal control group, PD model group (untreated group), PD model (Medopa group), PD model (Baicalin low dose group) PD model (Baicalin medium dose group) and PD model (Baicalin high dose group). Except for the normal control group, 6-OHDA was injected using microinjection under the mouse brain stereotaxic apparatus to establish the hemiparkinsonian PD model. On the basis of the success of making model, the rats were treated by Medopa and Baicalin (low, medium and high dose). Immunohistochemistry was used to detect tyrosine hydroxylase (TH) and Cx36 expression in cerebral cortex and striatum of the 6 groups. Western-Blot technique was used to detect the cerebral cortex and striatum Cx36 expression changes, and to preliminarily study the effect of Baicalin on rat cerebral cortex and striatum Cx36 expression levels. Results: Immunohistochemical staining and Western blotting showed that the expression of TH-positive neurons and Cx36 in the cerebral cortex and striatum of the PD model group was lower than that of the normal control group (828±188). While expressions of Cx36 in the low, medium and high dose PD model groups of Baicalin (733±118, 759±134, 779±125) were up-regulated, compared with the untreated PD model group (487±125), and the differences were statistically significant (all P<0.05), but the difference between the doses was not statistically significant (P>0.05). Conclusion: The expression of Cx36 decreases in cerebral cortex and striatum area of 6-OHDA-induced Parkinson's disease model rats, and the expressions of TH and Cx36 in cerebral cortex and striatum increase after treatment with Baicalin, which may provide new drug research direction for Parkinson's disease.

Role of immune-related GTPase M1 in cortical neurons autophagy of mice with sepsis-induced brain injury

To investigate the role of immune-related GTPase M1 (IRGM1) in cortical neurons autophagy in mice with sepsis induced brain injury (SIBI). Methods: Sixty wild-type C57BL/6 mice and sixty IRGM1 gene knockout C57BL/6 mice were randomly divided into 4 groups: a sham-operated wild-type (SWT) group, a cecal ligation and puncture (CLP) model wild-type (MWT) group, a sham-operated knockout (SKO) group, and a CLP model knockout (MKO) group. Models of mice with sepsis were established by CLP. Six hours of after CLP, the neurobehavioral scores for mice were recorded. The mice were diagnosed with SIBI and enrolled for the studies in next step if the neurobehavioral score was less than 6 in the MWT and MKO groups. The sham operation group only opened the abdominal cavity without CLP. Pathological changes in mouse cerebral cortex were observed by HE staining. Electron microscope was used to observe the ultrastructure of autophagy in cortical neurons. The expression of IRGM1 and INF-γ mRNA in the cerebral cortex of mice were detected by Real time quantitative PCR. The protein expression of microtubule-associated protein 1 light chain 3 (LC3)-II, LC3-I, sequestosome-1 (SQSTM1) and IRGM1 were measured by Western blot. Immunofluorescence staining was used to examine the expression of IRGM1 in mouse cortical neurons. Results: In the MWT group, the cortical neurons showed dilated endoplasmic reticulum, swelling mitochondria, and increased number of autophagosomes after 6 or 24 h of CLP in contrast to the SWT group. At 6 h after CLP, the expression of LC3-II in the cerebral cortex began to up-regulate, and the up-regulation was maintained till 96 h after CLP; on the contrary, SQSTM1 began to decline after 6 h of CLP. Compared with SWT group, IRGM1 was strongly up-regulated in the cerebral cortex of mice at both mRNA and protein levels in the MWT group after 12 h of CLP, and the mRNA expression of IFN-γ was also increased significantly (P<0.05). At 24 h after CLP, the IRGM1 expression of cortical neurons in the MWT group was significantly higher than that in the SWT group. The baseline of autophagy activity was quite low in the cerebral cortex cells in the SWT and the SKO groups. There was almost no detected expression of LC3-II; conversely, the expression of SQSTM1 was very high after 12 h of CLP. However, the expression of LC3-II was significantly up-regulated and the expression of SQSTM1 was down-regulated in the MWT group (P<0.05). On the other hand, there was almost no detected LC3-II expression in cerebral cortex in the MKO group, and the expression of SQSTM1 was up-regulated. At 6 h after CLP, the incidence of SIBI was 90% (27/30) in the MWT group, and 96.67% (29/30) in the MKO group. At 12 h of CLP, the neurobehavioral scores in the MKO group was significantly lower than that in the MWT group (4.97±0.71 vs 5.43±0.86; t=2.284, P=0.026). HE staining showed that mice in the MKO group suffered severe cerebral cortex injury, and the number of nerve cells was significantly reduced compared with that in the MWT group. Conclusion: The IRGM1 exerts a protective effect on the brain of the mice with SIBI, and its mechanism might be related to the regulation of autophagy in mouse cortical neurons.

Annotation and cluster analysis of spatiotemporal- and sex-related lncRNA expression in rhesus macaque brain.

Long noncoding RNAs (lncRNAs) mediate important epigenetic regulation in a wide range of biological processes and diseases. We applied comprehensive analyses of RNA-seq and CAGE-seq (cap analysis of gene expression and sequencing) to characterize the dynamic changes in lncRNA expression in rhesus macaque (Macaca mulatta) brain in four representative age groups. We identified 18 anatomically diverse lncRNA modules and 14 mRNA modules representing spatial, age, and sex specificities. Spatiotemporal- and sex-biased changes in lncRNA expression were generally higher than those observed in mRNA expression. A negative correlation between lncRNA and mRNA expression in cerebral cortex was observed and functionally validated. Our findings offer a fresh insight into spatial-, age-, and sex-biased changes in lncRNA expression in macaque brain and suggest that the changes represent a previously unappreciated regulatory system that potentially contributes to brain development and aging.

The Role of CBS in Injury Time Estimation after Brain Contusion

To observe the changes of cystathionine β-synthase （CBS） expression in the cerebral cortex after brain contusion at different times. An experimental model of traumatic brain injury （TBI） in mice was established by an improved weight-drop device. Then Western blotting and immunohistochemical examination were used to detect the CBS expression in cerebral cortex around injury at different time points （1 h, 6 h, 12 h, 1 d, 2 d, 3 d, 7 d）. The results of Western blotting revealed that the expression level of CBS was down-regulated and reached its lowest level at the 3rd days after injury, and then restored to normal level after 7 days. The results of immunohistochemistry showed that CBS was present in the normal brain cortex. CBS expression gradually decreased at the 3rd days after injury, and then restored to normal level after 7 days. CBS has the potential to be a reference index for time estimation after brain contusion in forensic practice.

PS 07-26 PRELIMINARY COMPARISON OF CEREBRAL CORTEX miRNAs LEVELS IN HYPERTENSIVE MICE AND CONTROL SUBJECTS BY SMALL RNA SEQUENCING

Objective: The pathogenesis of hypertension-related cognitive impairment has not been sufficiently clarified, current therapies for this disease are inadequate and new molecular targets are needed. MicroRNAs (miRNAs) are small, noncoding RNAs that function in complex networks to regulate protein expression. In the brain, they are involved in development and synaptic plasticity. In this study, we aimed to identify miRNAs with a differential expression in cerebral cortex from hypertensive mice and control subjects using small RNA sequencing. Design and Method: We used subcutaneous mini-pumps containing a concentration of Ang II that induces malignant hypertension or a saline solution for 28 days. Blood pressure was carefully monitored by a non-invasive tail-cuff method every week throughout the experiment. Spatial memory was assessed using the Morris water maze test. Total RNA was extracted from cerebral cortex. MiRNAs expression profiles were respectively determined by the sequencing analysis. Results: Compared to control group, the treatment of Ang II significantly raised the systolic blood pressure constant throughout the experiment in adult male mice (p < 0.05). The percentage of time spent in the target quadrant in probe test were significantly reduced in Ang II-dependent hypertensive mice(p < 0.05). 25 miRNAs were screened out to be significantly up-regulated compared to that of control mice, and 14 miRNAs were screened out to be remarkably down-regulated compared to that of control mice (P value < 0.05 and Fold change > 2). These differentially expressed miRNAs were predicted to target a large number of genes that involved in long-term potentiation, wnt signaling pathway, neurotrophin signaling pathway and other cellular bio-functions. Conclusions: Memory were impaired in angiotensin II-dependent hypertensive mice, the abnormal expression of several miRNAs in cerebral cortex of hypertensive mice suggests some of them may be involved in the pathogenesis of hypertension-related cognitive impairment, which requires further analysis and study.

Effects of maternal lead exposure on RGMa and RGMb expression in the hippocampus and cerebral cortex of mouse pups.

The present study focused on the RGM (repulsive guidance molecule) a and RGMb expression in cerebral cortex and hippocampus of newborn mice with maternal lead exposure. Lead exposure initiated from gestation to weaning. Lead acetate was dissolved in deionized water with concentrations of 0.1%, 0.2% and 0.5% groups respectively. On the 21st postnatal day, lead in blood and tissue levels was examined by GFAAS. The protein expressions of RGMa and RGMb in hippocampus and cerebral cortex tissues were tested by western blotting and immunohistochemistry. Comparing with the control group, the lead levels in blood, cerebral cortex and hippocampus of newborn mice in 0.1%, 0.2% and 0.5% lead exposure groups were remarkably higher (P<0.05). Compared with the control group, the RGMa and RGMb expression in hippocampus were upregulated in lead exposed groups (P<0.05), and the RGMa and RGMb expression in cerebral cortex were also higher (P<0.05). The increased expression of RGMa and RGMb in hippocampus and cerebral cortex may lead to the neurotoxicity in the context of maternal lead exposure.

Original Research: The expression of MMP2 and MMP9 in the hippocampus and cerebral cortex of newborn mice under maternal lead exposure.

The current study focused on the MMP2 and MMP9 expression in cerebral cortex and hippocampus of newborn mice under maternal lead exposure. Lead exposure was initiated from gestation to weaning. Lead acetate was dissolved in deionized water with concentration of 0.1, 0.2, and 0.5% and was absorbed through daily drinking. On day 21 after birth, lead in blood and tissue levels was examined by Graphite Furnace Atomic Absorption Spectrum (GFAAS). The protein expressions of MMP2 and MMP9 in hippocampus and cerebral cortex tissues were tested by western blotting and immunohistochemistry. Compared to the control group, blood, cerebral cortex, and hippocampus lead levels of newborn mice in 0.1, 0.2, and 0.5% lead exposure groups were markedly high (P < 0.05), and mice within the 0.2 and 0.5% lead exposure groups performed much worse than that of the control group in Water Maze test (P < 0.05). Compared with the control group, MMP2 and MMP9 expressions in hippocampus were up-regulated in the lead exposure groups (P < 0.05), and the MMP2 and MMP9 expressions in cerebral cortex were also higher (P < 0.05). The increased expression of MMP2 and MMP9 in the hippocampus and cerebral cortex may lead to the neurotoxicity in the context of maternal lead exposure.