The role of glycogen synthase kinase 3 beta in brain injury induced by myocardial ischemia/reperfusion injury in a rat model of diabetes mellitus

Myocardial ischemia/reperfusion injury can lead to severe brain injury.Glycogen synthase kinase 3 beta is known to be involved in myocardial ischemia/reperfusion injury and diabetes mellitus.However,the precise role of glycogen synthase kinase 3 beta in myocardial ischemia/reperfusion injury-induced brain injury is unclear.In this study,we observed the effects of glycogen synthase kinase 3 beta on brain injury induced by myocardial ischemia/reperfusion injury in diabetic rats.Rat models of diabetes mellitus were generated via intraperitoneal injection of streptozotocin.Models of myocardial ischemia/reperfusion injury were generated by occluding the anterior descending branch of the left coronary artery.Post-conditioning comprised three cycles of ischemia/reperfusion.Immunohistochemical staining and western blot assays demonstrated that after 48 hours of reperfusion,the structure of the brain was seriously damaged in the experimental rats compared with normal controls.Expression of Bax,interleukin-6,interleukin-8,terminal deoxynucleotidyl transferase d UTP nick end labeling,and cleaved caspase-3 in the brain was significantly increased,while expression of Bcl-2,interleukin-10,and phospho-glycogen synthase kinase 3 beta was decreased.Diabetes mellitus can aggravate inflammatory reactions and apoptosis.Ischemic post-conditioning with glycogen synthase kinase 3 beta inhibitor lithium chloride can effectively reverse these changes.Our results showed that myocardial ischemic post-conditioning attenuated myocardial ischemia/reperfusion injury-induced brain injury by activating glycogen synthase kinase 3 beta.According to these results,glycogen synthase kinase 3 beta appears to be an important factor in brain injury induced by myocardial ischemia/reperfusion injury.

Lithium chloride ameliorates learning and memory ability and inhibits glycogen synthase kinase-3 beta activity in a mouse model of fragile X syndrome

In the present study,Fmr1 knockout mice （KO mice） were used as the model for fragile X syndrome.The results of step-through and step-down tests demonstrated that Fmr1 KO mice had shorter latencies and more error counts,indicating a learning and memory disorder.After treatment with 30,60,90,120,or 200 mg/kg lithium chloride,the learning and memory abilities of the Fmr1 KO mice were significantly ameliorated,in particular,the 200 mg/kg lithium chloride treatment had the most significant effect.Western blot analysis showed that lithium chloride significantly enhanced the expression of phosphorylated glycogen synthase kinase 3 beta,an inactive form of glycogen synthase kinase 3 beta,in the cerebral cortex and hippocampus of the Fmr1 KO mice.These results indicated that lithium chloride improved learning and memory in the Fmr1 KO mice,possibly by inhibiting glycogen synthase kinase 3 beta activity.

GSK3β inhibitor promotes myelination and mitigates muscle atrophy after peripheral nerve injury

Delay of axon regeneration after peripheral nerve injury usually leads to progressive muscle atrophy and poor functional recovery. The Wnt/β-catenin signaling pathway is considered to be one of the main molecular mechanisms that lead to skeletal muscle atrophy in the elderly. We hold the hypothesis that the innervation of target muscle can be promoted by accelerating axon regeneration and decelerating muscle cell degeneration so as to improve functional recovery of skeletal muscle following peripheral nerve injury. This process may be associated with the Wnt/β-catenin signaling pathway. Our study designed in vitro cell models to simulate myelin regeneration and muscle atrophy. We investigated the effects of SB216763, a glycogen synthase kinase 3 beta inhibitor, on the two major murine cell lines RSC96 and C2C12 derived from Schwann cells and muscle satellite cells. The results showed that SB216763 stimulated the Schwann cell migra- tion and myotube contraction. Quantitative polymerase chain reaction results demonstrated that myelin related genes, myelin associated glycoprotein and cyclin-D1, muscle related gene myogenin and endplate-associated gene nicotinic acetylcholine receptors levels were stimulated by SB216763. Immunocytochemical staining revealed that the expressions of ^-catenin in the RSC96 and C2C12 cytosolic and nuclear compartments were increased in the SB216763-treated cells. These findings confirm that the glycogen synthase kinase 3 beta in- hibitor, SB216763, promoted the myelination and myotube differentiation through the Wnt/β-catenin signaling pathway and contributed to nerve remyelination and reduced denervated muscle atrophy after peripheral nerve injury.

Adult neural stem cell dysfunction in the subventricular zone of the lateral ventricle leads to diabetic olfactory defects

Sensitive smell discrimination is based on structural plasticity of the olfactory bulb,which depends on migration and integration of newborn neurons from the subventricular zone.In this study,we examined the relationship between neural stem cell status in the subventricular zone and olfactory function in rats with diabetes mellitus.Streptozotocin was injected through the femoral vein to induce type 1 diabetes mellitus in Sprague-Dawley rats.Two months after injection,olfactory sensitivity was decreased in diabetic rats.Meanwhile,the number of Brd U-positive and Brd U＋/DCX＋double-labeled cells was lower in the subventricular zone of diabetic rats compared with agematched normal rats.Western blot results revealed downregulated expression of insulin receptorβ,phosphorylated glycogen synthase kinase 3β,and β-catenin in the subventricular zone of diabetic rats.Altogether,these results indicate that diabetes mellitus causes insulin deficiency,which negatively regulates glycogen synthase kinase 3β and enhances β-catenin degradation,with these changes inhibiting neural stem cell proliferation.Further,these signaling pathways affect proliferation and differentiation of neural stem cells in the subventricular zone.Dysfunction of subventricular zone neural stem cells causes a decline in olfactory bulb structural plasticity and impairs olfactory sensitivity in diabetic rats.

The Mechanism of Cornus officinalis Total Glycosides and Cornus Polysaccharide on Myocardial Protection in Rats with Acute Myocardial Infarction

Objective: To investigate effects of Cornus officinalis Total Glycosides (COTG) and Cornus Polysaccharide (CP) on myocardial protection and on expression of mitochondria biogenesis related gene of acute myocardial infarction (AMI) rats, Materials and Methods: Ninety-six SD rats of SPF level were randomly divided into 5 groups: sham operation group, model group, preventive treatment group, COTG treatment group, CP treatment group, and there were 12 cases in each one. By legating the left anterior descending branch of coronary artery method, acute myocardial infarction model was established. The rat of sham operation group and model group was intragastric administered with physiological saline;other groups were given with corresponding drugs. The cardiac function, the myocardial infarct area, the expression of mitochondrial biogenesis genes such as PGC-1α, PGC-1β, NRF-1mRNA and GSK-3β mRNA, GSK-3β Protein Expression were analyzed. Results: The results revealed that compared with model group, myocardial infarction size, LVDs, LVDd, LVESV, LVEDP, and -dp/dt decreased;LVSP increased in preventive treatment group, COTG treatment group, and CP treatment group (p < 0.05);LVEDV increased in preventive treatment group (p < 0.05), PGC 1 alpha, and PGC 1 beta;the NRF-1 mRNA expression increased in preventive treatment group, COTG treatment group, and CP treatment group (p < 0.05). Compared with CP and COTG treatment group, PGClpha, beta PGC 1, the NRF-1 mRNA expression increased in preventive treatment group (p < 0.05). Compared with the sham operation group, GSK-3 beta mRNA and protein expression increased in model group, preventive treatment group, COTG treatment group, and CP treatment group (p < 0.05). Compared with model group, GSK-3 beta mRNA expression reduced in preventive treatment group, COTG treatment group, and CP treatment group (p Cornus officinalis total glycosides and Cornus polysaccharides can effectively protect myocardial mitochondria of acute myocardial infarction rats by activating GSK-3β signaling pathways, and reduce the myocardial infarct size, which has great significance for improving cardiac function.

Anticancer activity of Δ^(9)-tetrahydrocannabinol and cannabinol in vitro and in human lung cancer xenograft

Objective:To investigate the effects of Δ^(9)-tetrahydrocannabinol,the principal psychoactive compound of Cannabis sativa,and cannabinol,a Δ^(9)-tetrahydrocannabinol degradative product,on human non-small cell lung cancer cells.Methods:Δ^(9)-Tetrahydrocannabinol and cannabinol were tested for anticancer activity in human non-small cell lung cancer(A549)cells.The effects on cell proliferation,apoptosis,and phosphorylation profiles were examined.The effects of Δ^(9)-tetrahydrocannabinol and cannabinol on tumor growth were also investigated using a xenograft nude mouse model.Apoptosis and targeted phosphorylation were verified by immunohistochemistry.Results:Δ^(9)-Tetrahydrocannabinol and cannabinol significantly inhibited cell proliferation and increased the number of apoptotic cells in a concentration-dependent manner.The Δ^(9)-tetrahydrocannabinol-and cannabinol-treated cells had lower levels of phosphorylated protein kinase B[AKT(S473)],glycogen synthase kinase 3 alpha/beta,and endothelial nitric oxide synthase compared to the controls.The study of xenograft mice revealed that tumors treated with 15 mg/kg Δ^(9)-tetrahydrocannabinol or 40 mg/kg cannabinol were significantly smaller than those of the control mice.The tumor progression rates in mice treated with 15 mg/kg Δ^(9)-tetrahydrocannabinol or 40 mg/kg cannabinol were significantly slower than in the control group.Conclusions:These findings indicate that Δ^(9)-tetrahydrocannabinol and cannabinol inhibit lung cancer cell growth by inhibiting AKT and its signaling pathways,which include glycogen synthase kinase 3 alpha/beta and endothelial nitric oxide synthase.

Progranulin promotes neurite outgrowth and neuronal differentiation by regulating GSK-3β

Progranulin(PGRN)has recently emerged as a key player in a subset of frontotemporal dementias(FTD).Numerous mutations in the progranulin gene have been identified in patients with familial or sporadic frontotemporal lobar degeneration(FTLD).In order to understand the molecular mechanisms by which PGRN deficiency leads to FTLD,we examined activity of PGRN in mouse cortical and hippocampal neurons and in human neuroblastoma SH-SY5Y cells.Treatment of mouse neurons with PGRN protein resulted in an increase in neurite outgrowth,supporting the role of PGRN as a neurotrophic factor.PGRN treatment stimulated phosphorylation of glycogen synthase kinase-3 beta(GSK-3β)in cultured neurons.Knockdown of PGRN in SH-SY5Y cells impaired retinoic acid induced differentiation and reduced the level of phosphorylated GSK-3β.PGRN knockdown cells were also more sensitized to staurosporineinduced apoptosis.These results reveal an important role of PGRN in neurite outgrowth and involvement of GSK-3βin mediating PGRN activity.Identification of GSK-3βactivation as a downstream event for PGRN signaling provides a mechanistic explanation for PGRN activity in the nervous system.Our work also suggest that loss of axonal growth stimulation during neural injury repair or deficits in axonal repair may contribute to neuronal damage or axonal loss in FTLD associated with PGRN mutations.Finally,our study suggests that modulating GSK-3βor similar signaling events may provide therapeutic benefits for FTLD cases associated with PGRN mutations.

Efficacy of active ingredients in Qingdai(Indigo Naturalis)on ulcerative colitis:a network pharmacology-based evaluation

OBJECTIVE:To elucidate the protective effect of Qingdai(Indigo Naturalis,QD)on ulcerative colitis(UC)by means of in silico and in vivo approaches.METHODS:A systems pharmacology analysis was performed to predict the active components of QD whereas the putative biological targets of QD against UC were obtained through target fishing,network cons-truction and enrichment analyses.Meanwhile,we examined the ameliorative effect of QD in a mouse model of dextran sulfate sodium(DSS)-induced colitis.During the 10-day experiment,the control and diseased mice were given with oral gavages of QD(1.3 g raw herbs·kg^(-1)·d^(-1))or 5-aminosalicylic acid(5-ASA,100 mg·kg^(-1)·d^(-1))every day.The underlying pharma-cological mechanisms of QD in UC were determined using polymerase chain reaction tests,histological staining,enzyme-linked immunoassays,and Western blotting analysis.RESULTS:Searching from various network pharmacology databases,29 compounds were identified in QD.According to the screening criteria suggested by TCMSP(i.e.OB≥30%and DL≥0.18),nine of them were considered the active ingredients that contribute to the ameliorative effects of QD on different mouse models of colitis.Most importantly,the protective effect of QD on DSS-induced colitis was significantly associated with modulations of the expression levels of glycogen synthase kinase 3-β(Gsk3-β)and forkhead box p3(Foxp3),which are widely considered as important regulators of excessive inflammatory responses.CONCLUSIONS:The results of this study provide solid scientific evidence for the use of QD or its core active components in the clinical management of UC.

Icariin Protects SH-SY5Y Cells from Formaldehyde-Induced Injury through Suppression of Tau Phosphorylation

Objective： To investigate the neuroprotective effects of icariin on formaldehyde （FA）-treated human neuroblastoma SH-SY5Y cells and the possible mechanisms involved. Methods： SH-SY5Y cells were divided into FA treatment group, FA treatment group with icariin, and the control group. Cell viability, apoptosis, and morphological changes were determined by cell counting kit-8 （CCK 8）, flow cytometry, and confocal microscopy, respectively. The phosphorylation of Tau protein was examined by western blotting. Results： FA showed a half lethal dose （LD50） of 0.3 mmol/L in SH-SY5Y cells under the experimental conditions. Icariin （1-10 μ mol/L） prevented FA-induced cell death in SH-SY5Y cells in a dose-dependent manner, with the optimal effect observed at 5 μmol/L. After FA treatment, the absorbance in FA group was 1.31±0.05, while in the group of icariin （5μmol/L） was 1.63±0.05. Examination of cell morphology by confocal microscopy demonstrated that 5 μmol/L icariin significantly attenuated FA-induced cell injury （P〈0.05）. Additionally, icariin inhibited FA-induced cell apoptosis in SH-SY5Y cells. Results from western blotting showed that icariin suppressed FA-induced phosphorylation at Thr 181 and Ser 396 of Tau protein, while having no effect on the expression of the total Tau protein level. Furthermore, FA activated Tau kinase glycogen synthase kinase 3 beta （GSK-3β） by enhancement of Y216 phosphorylation, but icariin reduced Y216 phosphorylation and increased Ser 9 phosphorylation. Conclusion： Icariin protects SH-SY5Y cells from FA-induced injury possibly through the inhibition of GSK-3β -mediated Tau phosphoryiation.