Geniposide attenuates cognitive dysfunction in sleep-deprived rats by inhibiting TLR4/NF-κB signaling pathway

AIM To investigate the effects of geniposide （Gen） on Toll like receptor 4/nuclear factor-κB （TLR4/NF-κB） signaling pathway and cognitive dysfunction in sleep deprived rats. METHODS Wistar rats （n=120） were randomly divided into normal control （NC） group, model （M） group, low-dose （5 g·kg^-1·d^-1） Gen （Gen-L） group, medium-dose （10 g·kg^-1·d^-1） Gen （Gen-M） group, high-dose （20 g·kg^-1·d^-1） Gen （Gen-H） group and Gen-H+LPS （0.4 mg·kg^-1·d^-1, tail vein injection） group. After 7 days of intervention, the sleep deprivation model of rats in M group, Gen-L, Gen-M, Gen-H and Gen-H+LPS group was established by improved small platform water environment. The escape latency of Morris water maze experiment and the behavior correct rate of Y maze experiment were measured. The serum levels of S100B and neuron-specific enolase （NSE）, and the levels of interleukin-1β （IL-1β）, IL-6 and tumor necrosis factor-α （TNF-α） in hippocampus were detected by ELISA. The mRNA levels of TLR4 and NF-κB p65 were detected by RT-qPCR, and the protein levels of TLR4 and NF-κB p65 were determined by Western blot. RESULTS Compared with NC group, the escape latency, the serum levels of S100B and NSE, the hippocampal levels of IL-1β, IL-6 and TNF-α, and the mRNA and protein expression of TLR4 and NF-κB p65 were increased significantly in M group （P<0.01）, and the behavior correct rate was decreased significantly （P<0.01）. Compared with M group, the escape latency, the hippocampal levels of IL-1β, IL-6 and TNF-α, and the expression of TLR4 and NF-κB p65 at mRNA and protein levels were decreased significantly in Gen-L, Gen-M and Gen-H groups （P<0.01）, and the behavior correct rate was increased in turn （P<0.01）. Compared with Gen-H group, the escape latency, the serum levels of S100B and NSE, the hippocampal levels of IL-1β, IL-6 and TNF-α, and the expression of TLR4 and NF-κB p65 at mRNA and protein levels were increased significantly in Gen-H+LPS group （P<0.01）, and the behavior correct rate was decreased significantly （P<0.01）. CONCLUSION Geniposide may inhibit the TLR4/NF-κB p65 signaling pathway to effectively improve cognitive function in sleep-deprived rats and reduce hippocampus inflammation.     

Baicalin attenuates pancreatic fibrosis by inhibiting TGF-β1/TAK-NF-κB signaling pathway in chronic pancreatitis mice

AIM: To explore the role of transforming growth factor-β1 (TGF-β1)/TGF-β-activated kinase (TAK)-nuclear factor-κB (NF-κB) signaling pathway in chronic pancreatitis (CP) mice and the effect of baicalin on pancreatic fibrosis in the mice. METHODS: Kunming mice (n=58) were randomly divided into 3 groups, including control group, CP group and baicalin group. The mice in CP group and baicalin group were intraperitoneally injected with 20% L-arginine. After 2 weeks of CP, the mice in baicalin group were intraperitoneally injected with baicalin (100 mg/kg, once a day). At 2 weeks, 4 weeks and 6 weeks after modeling, the mice were anesthetized and sacrificed. The morphological changes of the pancreas were observed by HE and Masson staining. The serum level of TGF-β1 was analyzed by ELISA. The expression of fibronectin (FN) and NF-κB in the pancreas was observed by immunohistochemistry staining. The protein levels of transforming growth factor-β receptor type Ⅰ (TGF-βRⅠ), phosphorylated TAK1 (p-TAK1) and NF-κB in the pancreas were determined by Western blot. The mRNA expression of matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloprotease-1 (TIMP-1) was detected by real-time PCR. RESULTS: At 2 weeks, 4 weeks and 6 weeks after intraperitoneal injection of L-arginine, the pancreatic tissues were obviously injured and exhibited different degrees of fibrosis, and FN expression was significantly increased. After treatment with baicalin, the degrees of pancreatic injury and fibrosis were significantly attenuated and the expression of FN was reduced (P<0.01). Compared with control group, the protein levels of TGF-β1, TGF-βRⅠ, p-TAK1, NF-κB and TIMP-1 in the pancreas of CP group were significantly increased, and the expression of MMP-1 was decreased at each time point. In baicalin group, the protein levels of TGF-β1, TGF-βRⅠ, p-TAK1, NF-κB and TIMP-1 were significantly decreased, and the expression of MMP-1 was markedly increased at the corresponding time points compared with CP group (P<0.01). CONCLUSION: Baicalin effectively atte-nuates pancreatic fibrosis by inhibiting the activation of TGF-β1/TAK-NF-κB signaling pathway and regulating the balance of MMP-1/TIMP-1.     

Astragaloside Ⅳ inhibits JAK2/STAT3 signaling pathway and alleviates severe acute pancreatitis-associated acute liver injury in rats

AIM: To investigate the effect of astragaloside Ⅳ on severe acute pancreatitis (SAP)-associated acute liver injury in the rats and to explore the underlying mechanisms. METHODS: Male Sprague-Dawley (SD) rats (n=96) were randomly divided into sham-operated group, SAP model group, astragaloside Ⅳ treatment group and AG490 treatment group. SAP model was induced by retrograde injection of 5% sodium taurocholate (1 mL/kg) into the biliopancreatic duct. The rats in astragaloside Ⅳ treatment group were intraperitoneally injected with 20 mg/kg astragaloside Ⅳ, while the rats in AG490 treatment group were injected with 8.0 mg/kg AG490 2 h before sodium taurocholate injection. The rats in sham-operated group and model group received the same volume of saline. The rats were sacrificed at 12 h, 18 h and 24 h after the treatment. The levels of ascites, serum amylase, ALT and AST were detected after the blood samples were collected by the puncture through inferior vena cava. The serum levels of TNF-α, IL-6 and IL-1β were also examined by ELISA. Furthermore, HE staining was used to observe the liver pathological changes, and the protein levels of p-JAK2 and p-STAT3 in the liver were evaluated by Western blot. RESULTS: Compared with sham-operated group, the levels of ascites, serum amylase, ALT, AST, IL-6, TNF-α and IL-1β in the rats in model group were significantly increased, while they were decreased in the rats in astragaloside Ⅳ treatment group and AG490 treatment group compared with the rats in model group. Meanwhile, the phosphorylation levels of JAK2 and STAT3 was significantly increased in model group compared with sham-operated group. The rats in astragaloside Ⅳ treatment group and AG490 treatment group both had a better improvement in the liver injury and lower phosphorylation levels of JAK2 and STAT3.CONCLUSION: Astragaloside Ⅳ exerts a protective effect on pancreatitis-associated acute liver injury in the rats possibly via inhibiting JAK2/STAT3 signaling pathway.     

RXRα agonist bexarotene inhibits atherosclerosis in ApoE-/- mice by regulating TGF-β1/Smad2 signaling pathway

AIM To observe the effect of retinoid X receptor α （RXRα） agonist bexarotene （Bex） on the proliferation of transforming growth factor β1 （TGF-β1）-induced vascular smooth muscle cells （VSMCs） and atherosclerosis in apolipoprotein E knockout （ApoE^-/-） mice, and to explore the underlying mechanism. METHODS Ten C57BL/6 mice were selected as normal control group, and 30 ApoE^-/- mice were randomly divided into 3 groups： ApoE^-/- group, ApoE^-/-+Bex5 （5 mg·kg^-1·d^-1 Bex） group and ApoE^-/-+Bex10 （10 mg·kg^-1·d^-1 Bex） group. Bex was intragastrically given once a day for 8 weeks. The levels of triglyceride （TG） and total cholesterol （TC） were determined by oxidase method, and select masking method was used to determine serum levels of low-density lipoprotein cholesterol （LDL-C） and high-density lipoprotein cholesterol （HDL-C）. The protein levels of TGF-β1, p-Smad2 and Smad2 were determined by Western blot. HE staining was used to observe the intima of the thoracic aorta. The VSMCs were cultured with tissue patch method, and the proliferation of VSMCs was measured by BrdU incorporation method. RESULTS The serum levels of TG, TC and LDL-C, and the expression of TGF-β1 and p-Smad2 in thoracic aorta in ApoE^-/- group were significantly higher than those in C57BL/6 group （P<0.01）. Bex increased p-Smad2 protein level in thoracic aorta in a dose-dependent manner, inhibited the intimal plaque formation and vascular medial proliferation, and decreased the plaque area in ApoE^-/- mice （P<0.01）. No significant difference in serum levels of TG, TC, HDL-C and LDL-C, and TGF-β1 and Smad2 expression in thoracic aorta among ApoE^-/- group, ApoE^-/-+Bex5 group and ApoE^-/-+Bex10 group was observed. TGF-β1 （0.1~10 μg/L） promoted the proliferation of VSMCs, while Bex （10^-9~10^-7 mol/L） inhibited TGF-β1 （5 μg/L）-induced proliferation of VSMCs in a concentration-dependent manner. Bex （10^-7 mol/L） synergistically promoted the protein level of p-Smad2 in VSMCs induced by TGF-β1 （P<0.01）, but inhibited TGF-β1-induced nuclear translocation of p-Smad2. CONCLUSION RXRα agonist Bex inhibits the formation of atherosclerosis in ApoE^-/- mice, and its mechanism may be related to the regulation of TGF-β1/Smad2 pathway.     

Effect of Notch1/Hes1 signaling pathway on proliferation and differentiation of AECⅡ by regulating expression of C/EBPα

AIM: To investigate whether Notch1/Hes1 signaling pathway regulates the expression of CCAAT/enhancer binding protein alpha (C/EBPα), thus affecting the proliferation and differentiation of type Ⅱ alveolar epithelial cells (AECⅡ). METHODS: Human AECⅡ were cultured in vitro, and randomly divided into control group, activator group (adding Notch pathway activator Jagged1 protein, 500 μg/L) and inhibitor group (adding Notch inhibitor DAPT, 10 μmol/L). AECⅡ in each group were collected after 24 h of intervention. The expression of Notch1, Hes1 and C/EBPα at mRNA and protein levels was determined by RT-qPCR and Western blot. The cell proliferation ability of the AECⅡ was measured by living cell counting and CCK-8 assay. The cell cycle distribution and differentiation of the AECⅡ were analyzed by flow cytometry. RESULTS: Compared with control group, the mRNA and protein expression levels of Notch1, Hes1 and C/EBPα were significantly increased in activator group (P<0.05), AECⅡ entered G₂/M phase from S phase, the proliferation of AECⅡ was increased, and the differentiation of AECⅡ was reduced (P<0.05). The mRNA and protein expression levels of Notch1, Hes1 and C/EBPα were significantly reduced in inhibitor group (P<0.05), the cell cycle of AECⅡ cells was arrested in G₀/G₁ phase, the proliferation of AECⅡ cells was reduced, and the differentiation of AECⅡ cells was increased (P<0.05). CONCLUSION: Notch1/Hes1 signaling pathway regulates the expression of C/EBPα and affects the proliferation and differentiation of AECⅡ.     

PPARγ affects epithelial-mesenchymal transition in renal tubular epithelial cells under high glucose by regulating AKT/FAK signaling pathway through PTEN

AIM To investigate the role of peroxisome proliferator-activited receptor γ （PPARγ） in the regulation of PTEN/AKT/FAK signaling pathway and epithelial-mesenchymal transition （EMT） in renal tubular epithelial cells grown in high-glucose environment. METHODS Renal tubular epithelial cells （NRK52E cells） cultured in high glucose were used as an in vitro model system. PPARγ was over-expressed or knocked down in these cells, and its effect on PTEN expression was determined by RT-qPCR, immunofluorescence and Western blot. The changes of EMT-related proteins were also measured. The PPARγ inhibitor GW9662 and the PPARγ agonist rosiglitazone were used along with PTEN over-expression or knockdown to determine whether the effects of PPARγ were mediated through PTEN. RESULTS PPARγ over-expression resulted in the increased expression of PTEN at mRNA and protein levels, the up-regulation of E-cadherin, and the down-regulation of vimentin and α-SMA. Knockdown of PPARγ expression reduced the mRNA and protein levels of PTEN, down-regulated E-cadherin, and up-regulated vimentin and α-SMA （P<0.05）. Treatment of the NRK-52E cells with GW9662 decreased PTEN expression and increased the protein levels of p-AKT （Thr308）, FAK and p-FAK （Tyr397）. These effects were rescued by PTEN over-expression. Treatment of the NRK-52E cells with rosiglitazone increased PTEN expression and decreased the protein levels of p-AKT （Thr308）, FAK and p-FAK （Tyr397）. These effects were rescued by PTEN knockdown. These changes were all statistically significant （P<0.05）. CONCLUSION PPARγ regulates the mRNA and protein expression of PTEN in renal tubular epithelial NRK52E cells, and affects EMT in renal tubular epithelial cells. The regulation of AKT/FAK signaling pathway by PPARγ is primarily mediated by PTEN.