Changes of canonical Wnt signaling pathway in brains of rats with autism induced by prenatal exposure to valproic acid

AIM：To investigate the roles of the canonical Wnt pathway in autism. METHODS：Using an autistic model induced by prenatal exposure to valproic acid (VPA), we detected the expression of the signaling molecules of the canonical Wnt pathway in the prefrontal cortex (PFC) and hippocampus formation (HF) of autistic rats. The expression levels of glycogen synthase kinase 3β (GSK-3β), phosphorylated GSK-3β, β-catenin and phosphorylated β-catenin were observed by Western blotting. The mRNA expression of GSK-3β, β-catenin, c-Myc and cyclin D1 was assessed by semi-quantitative RT-PCR. RESULTS：The results of Western blotting showed that inactivated GSK-3β (Ser9) phosphorylation was significantly increased, and inhibitory β-catenin (Ser33/37/Thr41) phosphorylation was obviously decreased compared with control group. The results of RT-PCR showed that the mRNA levels of β-catenin, c-Myc and cyclin D1 increased, and GSK-3β was significantly enhanced in VPA-exposed rats compared with the controls. CONCLUSION：Increased activity of canonical Wnt pathway in the PFC and HF of autistic rats may contribute to the susceptibility to autism.     

Panaxadiol saponins induce activation of MAPK/ERK signaling pathway in bone marrow cells of aplastic anemia mice

AIM: To observe the effects of panaxadiol saponins (PDS) on up-regulation of MAPK/ERK signal pathway in bone marrow cells and increase in regulatory T (Treg) cells in spleen tissue of aplastic anemia (AA) mice, and to explore the mechanisms. METHODS: For preparation of immune-mediated AA model, BALB/c mice were exposed to sublethal dose (5.0 Gy) of[⁶⁰Co]-γ radiation, followed by transplantation of lymphocytes from DBA/2 donor mice. BALB/c mice (n=60) were randomly divided into 6 groups, including normal mouse group, AA model group, PDS treatment groups at low, medium and high doses, and cyclosporine group as positive control. PDS and cyclosporine were given by gavage for 14 d. The peripheral blood cell counts and bone marrow pathological examination were tested. The protein levels of MEK1/2, p-MEK1/2, ERK1/2 and p-ERK1/2 in the bone marrow cells were analyzed by Western blot and immunohistochemistry experiment. Flow cytometry was used to detect the proportion of Treg cells in spleen tissue of each group. RESULTS: The peripheral blood cell counts were significantly decreased in AA mouse group as compared with normal mouse group (P<0.05). The bone marrow sections showed markedly inhibition status of hematopoiesis and the decrease in cellularity. In response to PDS treatment, the peripheral blood cell counts and Treg cells in the spleen tissues of AA mouse treated with PDS were significantly increased in a dose-dependent manner (P<0.05). Treatment with PDS at medium and high doses up-regulated the protein levels of MEK1/2, p-MEK1/2, ERK1/2 and p-ERK1/2 in the bone marrow of AA mice (P<0.05). CONCLUSION: PDS is effective to enhance recovery of hematopoietic function in AA mice. This effect may be related to up-regulating multiple protein kinases of MAPK/ERK signal pathway in the bone marrow cells of AA mice. In addition, PDS has an impact on immune function of AA mice.     

Role of Wnt signaling pathway in development of radioresistance in esophageal cancer

AIM:To investigate the role of Wnt signaling pathway in the development of radioresistance in esophageal cancer cells. METHODS:The mRNA expression of the genes involved in Wnt signaling pathway was determined by real-time RT-PCR. The protein levels involved in Wnt signaling pathway were also confirmed by Western blotting and immunofluorescence method. Xenograft assay was performed to compare the proliferation ability and tumorigenicity of the cell lines. RESULTS:Up-regulation of Wnt1 induced the activation of Wnt signaling pathway and the variation of the downstream genes. β-catenin was accumulated and nuclear-transferred. The expression of downstream targeted genes such as cyclin D1 and WISP1 was increased. The radioresistant esophageal cancer cells showed higher proliferation ability and tumorigenicity in nude mouse xenograft. CONCLUSION:Wnt signaling-induced acceleration of proliferation is important for the development of radioresistance in esophageal cancer cells.     

Effect of Shaofu-Zhuyu decoction on MAPK/ERK signaling pathway in rats with endometriosis

AIM: To observe the effects of Shaofu-Zhuyu decoction (SFZY) on mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) signaling pathway in the rats with endometriosis (EM), and to explore the mechanism of SFZY for treatment of EM.METHODS: Healthy female SD rats were used to establish the EM model. The rats were randomly divided into blank control group, model group, positive control group, and low dose, middle dose and high dose of SFZY groups. The pathological changes of the endometriotic tissue were observed by HE staining. The levels of tumor necrosis factor-α (TNF-α), interleukin-6(IL-6) and IL-8 in the uterine tissue were detected by ELISA. The mRNA expression of ERK, vascular endothelial growh factor (VEGF) and matrix metalloprotein-9 (MMP-9) was detected by RT-qPCR. The protein expression of nuclear factor-κB (NF-κB), MAPK and MAPK-ERK kinase (MEK) was determined by Western blot.RESULTS: Compared with model group, the levels of TNF-α, IL-6 and IL-8 in the uterine tissue of the rats in middle dose and high dose of SFZY groups were significantly decreased (P<0.05), the mRNA expression of ERK, VEGF and MMP-9 was significantly reduced, and the protein expression of NF-κB, MEK and MAPK was decreased significantly in the rat endometriotic tissues (P<0.05).CONCLUSION: SFZY may play a key role in the treatment of EM by regulating MAPK/ERK signaling pathway.     

草莓白化相关病毒中国分离物全基因组分析

草莓白化相关病毒(strawberrypallidosis-associatedvirus,SPa V)属于长线形病毒科(Closteroviridae)毛形病毒属(Crinivirus),可引起草莓病害,2017年在中国首次报道。采用高通量测序、RACE和RT-PCR技术获得了SPa V中国分离物(FJ)的基因组全长。该病毒含有两条正单链基因组RNA1和RNA2。RNA1全长8 048 nt,5′和3′非编码区序列分别为264和197 nt,含有3个开放阅读框(ORF),分别编码ORF 1a/1b融合蛋白和p9蛋白。RNA2全长7 977 nt,5′和3′非编码区序列分别为248和186 nt,含有8个开放阅读框(ORF),分别编码HSP70h、CPh、CP、CPm、p7、p6、p9和p28等8个蛋白。RNA1和RNA2与美国M1分离物分别具有98.5%和99.0%的核苷酸一致性;系统发育分析结果表明,SPa V中国分离物(FJ)单独处在一个分支。对SPa V来源的小RNA的分析表明,来源于SPa V的小RAN长度以21和22 nt为主。     

Asiaticoside attenuates hypoxic pulmonary hypertension in mice by inhibiting NF-κB/p38 signaling pathway

AIM: To investigate whether asiaticoside attenuates hypoxic pulmonary hypertension by inhibiting p38/NF-κB signaling pathway. METHODS: BALB/c mice (n=30) were randomly divided into normoxia (N) group, hypoxia (H) group, and hypoxia+asiaticoside group. Right ventricular systolic pressure (RVSP), mean carotid artery pressure (mCAP), the weight ratio of right ventricle/(left ventricle+ventricular septum)[RV/(LV+S)], the ratio of right ventricle/body weight (RV/BW), vessel wall area/vessel total area (WA/TA) and vessel wall diameter/vessel wall total diameter (WT/TT) were determined after the model was established. The protein levels of p38, p-p38, NF-κB and p-NF-κB in the lung tissues were detected by Western blot. The fluorescence intensity of p-p38 and p-NF-κB were measured by immunofluorescence method. The serum levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were measured by ELISA. RESULTS: Compared with N group, the levels of RVSP, RV/(LV+S), RV/BW, WA/TA and WT/TT were significantly increased in H group, while administration of asiaticoside decreased the levels of RVSP, RV/(LV+S), RV/BW, WA/TA and WT/TT (P<0.05). Compared with N group, the relative protein levels of p-p38 and p-NF-κB in H group were significantly increased (P<0.05), and the concentrations of IL-6 and TNF-α were significantly increased, which were apparently attenuated by asiaticoside injection. CONCLUSION: Inhibition of p38/NF-κB signaling pathway and reduction of inflammatory responses may be the important mechanisms of asiaticoside in the prevention and treatment of hypoxic pulmonary hypertension.     

Dihydroartemisinin enhances radiotherapy efficiency in H22 cell tumor-bearing mice by regulating PI3K/AKT signaling pathway

AIM To study the effect of dihydroartemisinin （DHA） on the radiotherapy efficiency in hepatocellular carcinoma H22 cell tumor-bearing mice and the role of phosphatidylinositol 3-kinase （PI3K）/protein kinase B （AKT） signaling pathway in this process. METHODS A model of H22 cell tumor-bearing mice was established. The mice was divided into model group, single radiotherapy group, 5-fluorouracil （5-FU） group, and low-, medium- and high-dose DHA groups. The body weight and tumor volume in each group were measured every other day. At the end of administration, blood was collected from the tail of the mice and the animals were killed by neck removal immediately. The synergistic effect of DHA on radiotherapy was determined, and tumor growth inhibitory rate was calculated. The degree of lymphocyte transformation and natural killer （NK） cell activity were measured by MTT, the serum levels of interleukin-2 （IL-2） and IL-4 were measured by ELISA, and the protein levels of PI3K, AKT and p-AKT were determined by Western blot. RESULTS The H22 cell tumor-bearing mouse model was successfully constructed. Compared with model group, the TGT₃ （tumor growth time to reach 3 times of volume） of single radiotherapy group was remarkably increased （P<0.05）, while tumor weight, lymphocyte transformation degree, NK cell activity, IL-2 and IL-4 levels, PI3K protein level and AKT phosphorylation level were remarkably decreased （P<0.05）. Compared with single radiotherapy group, TGT₃, EF （enhancement factor）, tumor inhibitory rate, lymphocyte transformation degree, NK cell activity, IL-2 level and IL-4 level were increased with the increase in DHA dose （P<0.05）, and the PI3K protein level and AKT phosphorylation level were decreased （P<0.05）. CONCLUSION DHA may enhance the immunity of tumor-bearing mice by inhibiting the activity of PI3K/AKT signaling pathway, thereby enhancing the efficacy of radiotherapy.     

Hyperbaric oxygen therapy activates CREB/BDNF signaling pathway to reduce synaptic damage in hippocampal neurons of Alzheimer disease mice

AIM To investigate the effect of hyperbaric oxygen (HBO) on synaptic damage of hippocampal neurons in APP/PS1 transgenic (TG) mice and its possible mechanism. METHODS The 6-month-old male APP/PS1 TG mice were randomly divided into TG group, HBO group and cAMP response element binding protein (CREB) inhibitor H89 group, with 10 mice in each group. Ten male wild-type (WT) C57BL/6 mice of the same age were used as negative control group (WT group). The mice in HBO and H89 groups were treated with HBO for 6 cycles, while the mice in WT group and TG group were not treated. The learning and memory abilities were observed by Morris water maze. The nesting ability of the mice was detected by nesting test. The Nissl bodies in hippocampal neurons were observed by Nissl staining. The mRNA expression of CREB and brain-derived neurotrophic factor (BDNF) in hippocampus was detected by real-time PCR. The protein levels of synapsin (SYN), postsynaptic density protein 95 (PSD95), growth-associated protein 43 (GAP43), CREB, phosphorylated CREB (p-CREB) and BDNF in the hippocampus were determined by Western blot. RESULTS Compared with WT group, the learning and memory abilities of the mice in TG group were signilficantly reduced (P<0.05). In addition, the nesting score, the number of Nissl bodies in the hippocampal neurons, the mRNA expression of CREB and BDNF, and the protein levels of SYN, PSD95, GAP43, p-CREB and BDNF were also decreased significantly (P<0.05). Compared with TG group, the learning and memory abilities of the mice in HBO group were improved (P<0.05). Meanwhile, the nesting scores of the mice were significantly increased (P<0.05), the neurons in the hippocampus were arranged neatly, and the number of Nissl bodies, the relative mRNA expression of CREB and BDNF,and the protein levels of SYN, PSD95, GAP43, p-CREB and BDNF were also increased significantly (P<0.05). Compared with HBO group, the mice in H89 group had poor learning and memory abilities, lowered nesting scores and decreased number of Nissl bodies. Futhermore, the relative mRNA expression of CREB and BDNF, and the protein levels of SYN, PSD95, GAP43, p-CREB and BDNF were also decreased significantly (P<0.05). CONCLUSION HBO improves the learning and memory abilities of APP/PS1 TG mice, and its mechanism may be related to activating the CREB/BDNF signaling pathway to reduce synaptic damage of hippocampal neurons in mice.     

Effect of chelerythrine on TGF-β/Smads signaling pathway in mouse livers with hepatic fibrosis

AIM:To investigate the anti-hepatic fibrosis effect of chelerythrine on mice and the regulation of transforming growth factor-β (TGF-β)/Smads signaling pathway. METHODS:C57BL/6N mice (n=50) were randomly divided into control group, model group and chelerythrine groups (10 mg·kg^-1·d^-1, 20 mg·kg^-1·d^-1 and 40 mg·kg^-1·d^-1, ig). The mouse model of hepatic fibrosis was established by intraperitoneal injection of carbon tetrachloride (CCl₄) in combination with the olive oil for 8 weeks. At the 5th week, different doses of chelerythrine was used to treat hepatic fibrosis in the mice. At the 14th week, hepatic index was detected. Histopathological changes and the degree of hepatic fibrosis were observed by hematoxylin-eosin staining and Van Gieson staining. The serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and hyaluronic acid (HA), and hepatic hydroxyproline (Hyp) content were assayed by spectrophotometry and ELISA. The mRNA expression of TGF-β₁, Smad3, Smad4 and Smad7 in the liver was detected by RT-qPCR, and the protein expression of TGF-β₁, Smad4 and Smad7 was determined by Western blot. RESULTS:The degree of hepatic fibrosis changed markedly in model group compared with control group. The hepatic index, the serum levels of ALT and AST, and the contents of HA and Hyp were significantly increased (P<0.05). The mRNA expression of TGF-β₁, Smad3 and Smad4 was significantly up-regulated, while the mRNA expression of Smad7 was significantly down-regulated (P<0.05). The protein expression of TGF-β₁ and Smad4 was significantly up-regulated, while the protein expression of Smad7 was significantly down-regulated (P<0.05). Compared with model group, the changes of the above indexes in chelerythrine groups were inhibited. CONCLUSION:Chelerythrine protects the mouse liver from CCl₄-induced fibrogenesis injury by regulating TGF-β/Smads signaling pathway.     

Effect of Hedgehog signaling pathway inhibitor on biological behavior of intrahepatic cholangiocarcinoma cell line RBE

AIM: To investigate the effect of cyclopamine, a Hedgehog(Hh) signaling pathway inhibitor, on the biological behavior of intrahepatic cholangiocarcinoma cell line RBE. METHODS: The proliferation of RBE cells was detected by cell counting with Typan blue staining and MTT assay, and the apoptosis was analyzed by the flow cytometry. The Transwell invasive cabin assay was used to detect the invasion ability, and Western blot was used to determine the protein expression of Gli1 and MMP-9 in the RBE cells before and after cyclopamine treatment. RESULTS: Cyclopamine inhibited the growth of RBE cells in a time-and dose-dependent manner. After cyclopamine treatment for 24 h, 48 h and 72 h, the apoptotic rates were significantly higher than those in control group. In control group, the number of cells invading through the Matrigel of invasion chamber was 154.52±13.61, while in experimental group it was 62.00±12.17, indicating that the invasion ability of the cells declined significantly. Furthermore, Western blot showed that the protein levels of Glil and MMP-9 in the RBE cells were decreased after treatment with cyclopamine for 24 h and 48 h. CONCLUSION: Blockage of the Hh signaling pathway with cyclopamine suppresses the proliferation, promotes the apoptosis and inhibits the invasion ability of RBE cells.     

Establishment of patient-derived esophageal squamous-cell carcinoma xenograft in mice and characteristics of signaling pathways related to proliferation in SCID mice

AIM: To establish and characterize the patient-derived esophageal squamous-cell carcinoma xenograft (PDECX) in mice. METHODS: The samples of human esophageal cancer were grafted into severe combined immunodeficient (SCID) mice. The xenografts were transferred to SCID mice when the first passage of xenografts grew up. The growth of tumors in the first, second and third passages was observed. HE staining was performed. The expression of CK5/6, p63 and p40 in the patient samples, and the first and third passages of the xenografts were detected by immunohistochemical analysis. The expression of mTOR, p-mTOR, p70S6K, p-p70S6K, Akt1, p-Akt (Ser473), Erk1/2 and p-Erk1/2 were determined by Western blot.RESULTS: The PDECX was successfully established. The positive expression of CK5/6, p63 and p40 in the xenografts was consistent with that in the patients' samples. The levels of phosphorylated and total proteins of proliferation-related signaling pathways were different in the xenografts from different patients.CONCLUSION: The PDECX model adequately reflects the tumal heterogeneity that is observed in the patients.     

Honokiol induces autophagy by inhibiting mTOR signaling pathway in lung cancer A549 cells

AIM:To investigate whether honokiol induces the autophagy of human lung cancer A549 cells and to explore its mechanism. METHODS:The A549 cells were cultured in vitro, and treated with honokiol at different concentrations (0, 10, 20, 40, 60 and 80 μmol/L) for 48 h. MTT assay was performed to analyze the effect of honokiol on the viability of the A549 cells. The formation of autophagosome was observed by staining with acridine orange under fluorescence microscope. The protein levels of autophagy-associated protein LC3, mTOR and p-mTOR in the A549 cells treated with honokiol, or combined with autophagy inhibitor 3-methyladenine (3-MA) were determined by Western blot. RESULTS:Honokiol significantly inhibited the viability of A549 cells in a dose-dependent manner (P<0.05). The number of the intracellular acidic autophageic vacuoles with bright red fluorescence was significantly increased after honokiol treatment. The protein level of LC3-Ⅱ/LC3-I in the A549 cells was significantly enhanced after honokiol (40 μmol/L) treatment, and the ratio of LC3-Ⅱ/LC3-I was significantly decreased by treatment with 3-MA (P<0.05). Furthermore, treatment with honokiol (40 μmol/L) in the A549 cells for 48 h also resulted in significant down-regulation of phosphorylated form of mTOR (P<0.01), while the total protein level was not changed. CONCLUSION:Honokiol significantly inhibits the growth of lung cancer A549 cells and induces the autophagy, which may be correlated with inhibition of mTOR signaling pathway.     

Oxidative stress-activated JNK-MAPK signaling pathway is involved in fluctuant high glucose-induced injury of hepatocytes

AIM: To explore the mechanisms of fluctuant high blood glucose-induced apoptosis of hepatocytes. METHODS: SD rats were randomly divided into normal control group (N), stable high blood glucose group (S), fluctuant high blood glucose group (F) and insulin group (I). Diabetic rats were induced by intraperitoneal injection of streptozotocin (65 mg/kg), and the fluctuant high blood glucose animal model was induced by intraperitoneal injection of ordinary insulin and glucose at different time points every day. The blood glucose fluctuation patterns of the animals in F group within 12 weeks were similar every day and no significant difference of the HbA1c concentration was observed compared with S group, indicating that the fluctuant hyperglycemia was successfully established in F group. The activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and the content of malondialdehyde (MDA) and nitric oxide (NO) in the homogenate of the liver tissues were detected by colorimetry. The mRNA and protein levels of JNK, p-JNK, Bax and Bcl-2 were examined by RT-PCR and Western blot. RESULTS: After 12 weeks, the increases in the intakes of food and water, the urine output, and the abnormal liver function were observed in S group, I group and F group. Compared with N group, the MDA level was increased, the content of NO and the activity of SOD and GSH-Px were decreased, and up-regulation of JNK mRNA and p-JNK and Bax proteins, and down-regulation of Bcl-2 were also found in S group, I group and F group. The above effects were more obviously showed in F group. CONCLUSION: Oxidative stress activates JNK-MAPK signaling pathway, which is involved in fluctuant high glucose-induced apoptosis of hepatocytes.     

Notch1 promotes renal tubulointerstitial fibrosis in renal tissues of diabetic mice by inhibiting autophagy through Akt/mTOR signaling pathway

AIM: To observe the changes of Notch1 expression and autophagy in the renal tissues of diabetic mice, and to explore the regulatory effect of Notch1 on tubulointerstitial fibrosis by inhibiting autophagy in diabetic nephro-pathy. METHODS: The mice were randomly divided into normal control group (db/m mice) and diabetes group (db/db mice), with 8 rats in each group. After 12 weeks of feeding, the mice were sacrificed and the corresponding biochemical indexes were measured. The protein expression of Notch1 in the renal tubular epithelial cells was observed by immunohistochemical staining. The protein levels of Notch1, PTEN, p-Akt (Thr308), Akt, p-mTOR (Ser2448), mTOR, LC3, P62, collagen type Ⅰ (Col-Ⅰ) and collagen type Ⅲ (Col-Ⅲ) were determined by Western blot. RESULTS: Compared with the db/m mice, the blood glucose, glycosylated hemoglobin, serum creatinine, triglyceride and total cholesterol were increased in the db/db mice (P<0.01). Renal tubular epithelial cell vacuolar degeneration, renal tubular expansion and interstitial inflammatory cell infiltration in db/db mouse renal tissues with HE staining were observed. The images of Masson staining showed collagenous fiber-like substance deposition in the glomerular capillaries and renal interstitium, and disarrangement of tubular structure in the renal tissues of db/db mice. The protein expression levels of PTEN and LC3-Ⅱ were decreased (P<0.01 or P<0.05), while the protein levels of Notch1, P62, p-mTOR (Ser2448), p-Akt (Thr308), Col-I and Col-III were increased in the db/db mice as compared with the db/m mice (P<0.01). However, no significant change of total mTOR and Akt proteins between the 2 groups was found. CONCLUSION: Notch1 protein expression was increased, PTEN expression was significantly reduced, Akt/mTOR pathway was activated, autophagy was inhibited, and fibrosis was aggravated in the renal tissues of the diabetic mice.     

PPARs signaling pathway is involved in diabetic hepatopathy in mice

AIM: To investigate the role of peroxisome proliferator-activated receptors (PPARs)-inflammation signaling pathways in diabetic hepatopathy. METHODS: Diabetic mouse model was established by feeding the mice with a high-energy diet for 4 weeks combined with intraperitoneal injection of streptozotocin (STZ; 40 mg·kg^-1·d^-1 for 5 d). The hepatopathy model was confirmed by histopathological observation and the indexes of liver function, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP), after another 4 weeks. Moreover, fasting blood glucose (FBG), and serum levels of total cholesterol (TC), triglyceride (TG) and insulin were measured, and the HOMA insulin resistance index (HOMA-IR) was calculated. The mRNA and protein expression levels of PPARs and inflammation-related factors were measured by qPCR and Western blot, respectively. RESULTS: After treatment with STZ for 7 d, the FBG of mice exceeded 11.1 mmol/L, suggesting that the diabetic model was established. After 4 weeks, the structural deformation of the hepatocytes (including hepatocytes containing abundant fat vacuoles, and inflammatory cell infiltration), and the increases in the serum levels of insulin, HOMA-IR, TC, TG, ALT, AST and ALP were observed (P<0.01), indicating the occurrence and progression of hepatopathy in diabetic mice. Meanwhile, compared with the control group, the mRNA and protein expression of PPARα, PPARβ and PPARγ decreased, but the expression of nuclear factor-κB (NF-κB), cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS) significantly increased in the diabetic hepatopathy mice (P<0.01). CONCLUSION: Down-regulation of PPARα, PPARβ and PPARγ and activation of NF-κB-COX-2/iNOS signaling pathways may be involved in the diabetic hepatopathy in mice induced by long-term high-energy diet feeding combined with intraperitoneal injection of STZ.     

Notch1 regulates activation of pancreatic stellate cells by non-classical Notch signaling pathway

AIM: To investigate the effect of Notch1 on the activation of pancreatic stellate cells (PSCs). METHODS: The expression of Notch1 in pancreatic duct adenocarcinoma (PDAC) tissues was detected by the immunohistochemical and immunofluorescence double staining. The PSCs were isolated, cultured, and identified by oil red O staining, Western blot and RT-qPCR. The expression of Notch1 and HES1 was detected by Western blot and RT-qPCR. After transfection of Notch1 siRNA to PSCs, Western blot was used to detect the protein expression of α-smooth muscle actin (α-SMA), fibronectin and collagen type Ⅰ (ColⅠ) in activated PSCs. The expression of Notch1 and HES1 was also detected by Western blot. The effects of Notch1 siRNA on migration ability and viability of PSCs were determine by scratch test and CCK-8 assay. RESULTS: The results of immunohistochemical and immunofluorescence double staining showed that Notch1 expressed in α-SMA positive cells in PDAC stroma. The mouse PSCs were successfully cultured, and the expression of α-SMA, fibronectin, ColⅠ, Notch1 and HES1 in activated PSCs were significantly increased compared with unactivated PSCs (P<0.01). After transfection of Notch1 siRNA to mouse PSCs, the expression of α-SMA and ColⅠ was significantly reduced compared with negative groups, but the expression of fibronectin and HES1 did not change significantly. After knock-down of Notch1 expression in activated PSCs, the migration ability and viability of PSCs were significantly reduced compared with negative group. CONCLUSION: Notch1 is involved in regulating the activation of PSCs. Knock-down of Notch1 expression inhibits the expression of the markers of activated PSCs, α-SMA and ColⅠ, reduces the activation of PSCs, and attenuates the migration capacity and viability of PSCs. Notch1 regulates the activation of PSCs without relying on the classic Notch signaling pathway.     

Acute cerebral ischemia activates EphB2/ephrin-B1/NMDA receptor signaling pathway to promote hippocampal neurogenesis in mice

AIM To investigate the effect of acute cerebral ischemia on hippocampal neurogenesis in mice and its possible mechanism involving EphB2/ephrin-B1/NMDA receptor signaling pathway. METHODS C57BL/6 mice (n=52) were randomly divided into sham group and acute cerebral ischemia group (model group). The model of acute cerebral ischemia in mice was established by bilateral common carotid artery occlusion. The pathological changes of the hippocampal CA1 region in mice were observed by HE staining. The learning and memory functions of the mice were assessed by Morris water maze. The BrdU positive cells and doublecortin (DCX) protein expression were observed by immunofluorescence staining for detecting hippocampal neurogenesis. The mRNA and protein expression levels of EphB2, ephrin-B1, reelin, microtubule-associated protein-2 (MAP-2) and NMDA receptor subunits NR2A and NR2B in the hippocampus were determined by RT-qPCR and Western blot. RESULTS The neuronal damage in the hippocampal CA1 region was significant (P<0.01), and the learning and memory functions were significantly decreased in the cerebral ischemia mice(P<0.01), suggesting that the cerebral ischemia model was successfully established. The BrdU positive cells and DCX protein expression were increased significantly (P<0.01), indicating that neurogenesis occurred in the hippocampus after cerebral ischemia. At the same time, the mRNA and protein expression levels of EphB2, ephrin-B1, reelin, MAP-2, NR2A and NR2B in the hippocampus were also significantly up-regulated (P<0.05). CONCLUSION Acute cerebral ischemia promotes the proliferation of hippocampal neural stem cells and endogenous neurogenesis, which may be related to the activation of EphB2/ephrin-B1/NMDA receptor signaling pathway.     

EdCC reduces myocardial ischemia-reperfusion injury via MEK-ERK signaling pathway

AIM: To investigate the myocardial protective effect of endometrial stem cell (EnSC)-derived cytokine cocktail (EdCC) on myocardial ischemic reperfusion injury and the MEK-ERK signaling pathway. METHODS: A mouse model of myocardial ischemic reperfusion injury was established. Infarct area, cell apoptosis, and expression of cleaved caspase-3 and phosphorylatied ERK1/2 were determined by TTC/Evans blue staining, TUNEL assay and Western blot, respectively. RESULTS: The mesenchymal characteristics were observed in the EnSCs with expressing CD90 and in absence of CD34 and CD45. EdCC contained (6 811±312) ng/g epidermal growth factor (EGF) protein. The phosphorylation of ERK1/2 markedly increased after injection of EdCC, but was abolished by MEK1 inhibitor PD98059 (5 mg/kg). EdCC decreased the infarct area and apoptotic cell number in the border zone and inhibited caspase-3 activation. However, the effects were abolished by MEK1 specific inhibitor PD98059. EGF did not decrease the infarct area, but the EGF receptor antagonist AG-1487 (6 mg/kg) partly abolished the myocardial protective effect of EdCC. CONCLUSION: EdCC protects the myocardium from ischemic reperfusion injury via activating MEK1-ERK signaling pathway, indicating an essential role in the transmission of stem cell therapy from the cell transplantation to cytokine based strategy.     

27-Hydroxycholesterol modulates lung cancer cell proliferation by activation of LXR signaling pathway

AIM:To investigate the effect of cholesterol metabolite 27-hydroxycholesterol (27-OHC) on the proliferation of lung cancer cells. METHODS:Human lung cancer A549 cells were treated with 27-OHC at different concentrations (0, 0.3125, 0.625, 1.25, 2.5, 5 and 10 μmol/L) for 24~48 h. The cell viability, cell cycle, cell prolife-ration, the intracellular cholesterol levels and cholesterol metabolism-related molecule expression were subsequently assessed by CCK-8 assay, flow cytometry, EdU staining, tissue total cholesterol detection kit, real-time PCR and Western blot. RESULTS:27-OHC decreased the viability of the A549 cells in a dose-and time-dependent manner (P<0.01) and inhibited the cell proliferation (P<0.05). The expression of typical liver X receptor (LXR) downstream target proteins including ATP-binding cassette transporter A1 (ABCA1), low-density lipoprotein receptor (LDLR), and 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CR) were modulated, which promoted the efflux of intracellular cholesterol, and reduced cholesterol influx and de novo synthesis, resulting in decreased intracellular cholesterol levels and cell viability. Furthermore, the inhibitory effect of 27-OHC on A549 cell viability was significantly attenuated after the LXR pathway was partially blocked by 5 μmol/L GSK2033 treatment (P<0.05). CONCLUSION:27-OHC inhibits A549 cell prolife-ration via activation of LXR signaling pathway.