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Objective:To investigate the mechanism by which glycoprotein non-transferable melanin B(GPNMB)regulates microglia M2 polarization to reduce nerve damage after cerebral ischemic stroke(CIS).Methods:SD rats were used for establishment of middle cerebral artery occlusion(MCAO)model.Neurons,astrocytes and microglia were cultured under oxygen and glucose depri-vation(OGD)conditions,and the expression of GPNMB in tissues and cells were measured by Western blot.Gpnmb wrapped with adeno-associated virus(AAV)or shRNA-Gpnmb were injected into rat brain tissues for overexpression or inhibition of GPNMB,modified neurological deficit score(mNSS),Rotarod fatigue test and tape removal test were used to evaluate rat nerve function,the proportion of cerebral infarction was determined by TTC staining,microglia M1/M2 polarization markers were detected by immunofluorescence and RT-PCR,and the expression of Phosphatidylinositol 3-kinase(PI3K)/Serine/threonine kinase(Akt)pathway was determined by Western blot.Microglia was cultured under OGD conditions in vitro,Gpnmb was overexpressed and PI3K expression were inhibited by LY294002,and M1/M2 polarization markers were measured.Results:Compared with normal rats or normal cultured cells,the expres-sion of GPNMB in MCAO model or OGD-intervened microglia was up-regulated(P<0.05);when Gpnmb was overexpressed in the brain tissue of MCAO rats,the mNSS score decreased,the Rotarod time of latency to fall lengthened,the contact time and removal time shortened in the tape removal test,the proportion of cerebral infarction decreased,the M1 polarization level of microglia decreased while the M2 polarization level increased,PI3K/Akt pathway activated,and these difference were statistically significant(P<0.05);inhibition of PI3K reversed the effect of overexpression of Gpnmb on promoting M2 polarization of microglia in vitro(P<0.05).Conclusion:GPNMB promotes M2 polarization of microglia by activating the PI3K/Akt pathway,thereby reducing nerve damage after CIS.
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OBJECTIVE To investigate the effect and mechanism of Poria cocos polysaccharides on the regulation of blood glucose in type 2 diabetes mellitus （T2DM）model rats by phosphatidylinositol 3-kinase（PI3K）/protein kinase B （Akt）/forked box transcription factor O 1（FoxO1）pathway. METHODS SD rats were randomly divided into blank control group （no modeling ，no administration），model group （modeling，no administration ），metformin group （modeling，200 mg/kg）and P. cocos polysaccharide low-dose，medium-dose and high-dose groups （modeling，100，200，400 mg/kg），8 in each group. Except for blank control group ， other groups were given high fat diet combined with streptozotocin to construct the model of T 2DM rats. At the same time ， administration groups were given relevant dose of medicine intragastrically ，and blank control group and model group were given constant volume of water intragastrically ，once a day ，for consecutive 42 days. During the experiment ，general condition and bodyweight of rats were observed every day ；fasting blood glucose （FBG）of rats were collected ，and oral glucose tolerance test were conducted and area under curve （AUC）was calculated the day before last administration. After last medication ，the heart ，liver， kidney organ index were calculated ；the levels of HbA 1c，TC，TG，MDA，SOD，GSH-Px and hepatic glycogen content were detected. HE staining was used to observe the pathological changes of liver and pancreatic tissue ，and the pathological grade score was calculated. Western blot assay was used to detect the protein expressions of p-PI 3K，p-Akt，p-FoxO1， PEPCK and G 6Pase in liver tissues. RESULTS Compared with blank control group ，the rats of model group suffered cc1965@163.com from polydipsia ，polyphagia and polyuria ；the body weight ， the levels of SOD and GSH-Px ，the protein expressions of p-PI 3K，p-Akt and p-FoxO 1 were significantly decreased （P＜0.05）；liver and kidney organ index ，blood glucose level at 0，0.5 and 2 hours after intragastric administration of glucose solution ，AUC， FBG，HbA1c，serum levels of MDA ，TC，TG and hepatic glycogen content ，liver and pancreatic pathological grade score ，the protein expressions of PEPCK and G 6Pase were all increased significantly （P＜0.05）. Compared with model group ，the general condition of rats in P. cocos polysaccharide groups were all improved ，and all of above indicators had been reversed to varying degrees. CONCLUSIONS P. cocos polysaccharide can downregulate protein expressions of PEPCK and G 6Pase which are key enzymes of gluconeogenesis ，inhibit hepatic gluconeogenesis ，effectively decrease blood glucose levels and regulate glucolipid metabolism in T 2DM model rats by weakening oxidative stress and upregulating PI 3K/Akt/FoxO1 pathway.
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Objective To observe the changes of corresponding proteins and function based on known clinical dihydroorotate dehydrogenase(DHODH) mutation types,i.e.,G202A,R346W and R135C in the patients with Miller syndrome.Methods HeLacell lines stably expressing Miller syndrome pathogenic mutation types G202A,R346W and R135C were established.Then the mitochondrial localization function,protein stability and enzyme activity of corresponding proteins were studied by the immunohistochemistry and mitochondrial layered positioning.Results The mitochondrial localization function of 3 kinds of DHODH mutation were not affected,which existed in the mitochondrial inner membrane after expression.The mutant G202A and R346W protein stability was reduced;the mutant R135C protein was stable,but base induced enzyme activity injury caused the deficiency of corresponding enzymatic activity.Conclusion The DHODH function injury may be related with the symptoms in Miller syndrome.
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Objective To observe the changes of the skeletal development related cells after dihydroorotate dehydrogenase (DHODH) deficiency.Methods The DHODH expression in MC3T3-E1 cells derived from mouse calvaria osteoblast precursor cells was inhibited by specific small interfering RNAs (siRNAs),and cell proliferation,ATP production and expression levels of bone-related genes were investigated in these cells.Results After reducing the DHODH expression by using specific siRNAs,cell proliferation was inhibited and cell cycle was arrested at G1/S stage.In addition,the ATP production was reduced in whole cells,especially in mitochondria.Furthermore,the expression levels of Runt-related transcription factor 2 (Runx2) and osteocalcin (Ocn) mRNAs in the DHODH inhibition group were decreased compared with the control group.Conclusion Inhibiting DHODH protein affects the differentiation and maturation of osteoblasts.The mitochondrial dysfunction in osteoblasts may be one of causes leading to the abnormal bone formation in Miller syndrome.