Apelin-13 inhibits nicotine-induced apoptosis of H9c2 cells via PI3K/Akt signaling pathway

AIM:To investigate the effect of apelin-13 on nicotine-induced apoptosis of cardiomyocytes and its potential molecular mechanism. METHODS:Rat H9c2 cells were treated with nicotine (10 μmol/L) to induced apoptosis. Flow cytometry was used to detect apoptotic rate. Western blot was used to determined the expression of related proteins. RESULTS:Compared with control group, nicotine treatment significantly increased the apoptotic rate of the H9c2 cells (P<0.01), and the protein levels of apoptosis-related proteins Bax and cleaved caspase-3, but markedly decreased the protein levels of Bcl-2, p-Akt, p-PI3K and APJ (P<0.05). Compared with nicotine group, apelin-13+nicotine significantly decreased the apoptotic rate of the H9c2 cells (P<0.01) and the the protein levels of Bax and cleaved caspase-3, but markedly increased the protein levels of Bcl-2, p-Akt, p-PI3K and APJ (P<0.05). Compared with apelin-13+nicotine group, apelin-13+nicotine+PI3K/Akt inhibitor LY294002 significantly increased the apoptotic rate of the H9c2 cells (P<0.01) and the protein levels of Bax and cleaved caspase-3, but markedly decreased the protein levels of Bcl-2, p-Akt and p-PI3K (P<0.05). CONCLUSION:Apelin-13 inhibits nicotine-induced apoptosis of H9c2 cells through PI3K/Akt signaling pathway.     

Overexpression of neuroglobin attenuates Aβ-induced apoptosis in brains of double transgenic AD mice

AIM: To observe the effects of neuroglobin(NGB) overexpression on the apoptosis induced by Aβ in the brains of double transgenic AD(APPswe/PS1dE9) mice and to explore its potential mechanisms.METHODS: Twenty-four 13-month-old double transgenic AD mice were randomly divided into 3 groups:intracerebroventricular injection with normal saline(NS) group, intracerebroventricular injection with pcDNA3.1 and NS group, and intracerebroventricular injection with pcDNA3.1 and pNGB group. Immunohistochemistry was used to detect the expression of Aβ_1-42 in the brains. TUNEL staining was used for analyzing the apoptosis, and the protein levels of cleaved caspase-3, caspase-9, PI3K, Akt and p-Akt were determined by Western blot.RESULTS: After intracerebroventricular injection with pNGB, the areas of Aβ_1-42 in the hippocampus and cortex were decreased compared with NS group and pcDNA3.1+NS group(P<0.01). The TUNEL-positive staining cells in the pNGB group were less than those in NS group and pcDNA3.1 group(P<0.01). NGB overexpression attenuated the protein levels of cleaved caspase-3 and caspase-9(P<0.01), but induced the production of PI3K and p-Akt(P<0.01).CONCLUSION: Overexpression of pNGB significantly inhibits the generation of Aβ and attenuates the apoptosis induced by Aβ, indicating that NGB overexpression activates PI3K/Akt pathway and inhibits the production of cleaved caspase-3 and caspase-9, which were tightly related with apoptosis.     

Effect of BDNF expression in cerebral cortex and hippocampus on ability of learning and memory in APP/PS1 transgenic mice

AIM: To investigate the expression changes of brain-derived neurotrophic factor (BDNF) in the cerebral cortex and hippocampus and their effects on the ability of learning and memory in the wild-type (WT) mice and APP/PS1 transgenic mice. METHODS: WT mice and APP/PS1 transgenic mice were selected as study subjects. Aβ plaques, apoptosis rate and BDNF expression in the cerebral cortex and hippocampus of WT mice and APP/PS1 transgenic mice were detected by the methods of Congo red staining, TUNEL, immunofluorescence and Western blot. The abilities of learning and memory were determined by Morris water maze test. RESULTS: The Aβ plaques appeared in the cerebral cortex and hippocampus of APP/PS1 transgenic mice, and the number of Aβ plaques in 12-month-old mice was larger than that in 6-month-old mice (P<0.05). The number of apoptotic neurons in the cerebral cortex and hippocampus of 12-month-old APP/PS1 transgenic mice was larger than that of WT mice (P<0.01). The expression level of BDNF in the cerebral cortex and hippocampus of WT mice was higher than that of APP/PS1 transgenic mice (P<0.01). The Morris water maze test showed that the escape latency in APP/PS1 transgenic mice was longer than that in WT mice, and the times across the platform quadrant in 60 s was less than that in WT mice (P<0.01). The swim-tracking path of APP/PS1 transgenic mice was disordered and irregular. CONCLUSION: The expression of BDNF in the cerebral cortex and hippocampus of APP/PS1 transgenic mice was lower than that of WT mice, accompanied by increased neuronal apoptosis and decreased spatial learning and memory ability. The decrease in learning and memory ability may be related to decreased BDNF expression in the cerebral cortex and hippocampus of APP/PS1 transgenic mice, leading to increased neuronal apoptosis, which may be one of the pathological mechanisms of Alzheimer disease.     

Irbesartan alleviates hepatic steatosis in db/db mice by inducing auto-phagy

AIM: To investigate the effect of irbesartan on the fatty liver of db/db mice and whether autophagy is involved in the process. METHODS: Male db/db mice (n=24) were randomly divided into model group and irbesartan group, and 12 db/m mice with similar age and weight were selected as normal control group. After 16 weeks of intervention respectively, the fatty liver-related parameters including body weight, liver index, blood lipid, liver function and pathological changes in the liver were observed. The protein levels of p-PI3K, p-Akt, and p-mTOR, as well as Atg-7, beclin-1 and LC3B in the liver tissues were detected by Western blot, and the autophagosomes in the liver were observed under electron microscope. RESULTS: Compared with the model group, the body weight, liver index, blood lipids, alanine and aspartate aminotransferase were decreased in irbesartan group (P<0.05). Moreover, the pathological changes in the liver were significantly ameliorated in irbesartan group than that of model group. Importantly, the protein levels of p-PI3K, p-Akt and p-mTOR were decreased with irbesartan administration, while the expression of Atg-7, beclin-1 and LC3B-Ⅱ was increased(P<0.05), which resulted in a distinct increase in autophagosomes. CONCLUSION: Irbesartan alleviates hepatic steatosis in db/db mice by inhibiting the PI3K/Akt/mTOR signaling pathway and upregulating the protein expression of Atg-7, beclin-1 and LC3B-Ⅱ, thereby inducing autophagy in hepatocytes.     

Resveratrol inhibits chondrosarcoma via mitochondrial and PI3K/Akt signaling pathways

AIM：To investigate the inhibitory effects of resveratrol on chondrosarcoma and the relation with mitochondrial and PI3K/Akt pathways. METHODS：Chondrosarcoma SW1353 cells were treated with resveratrol at concentrations of 25, 50 and 100 μmol/L for the time intervals of 24 h, 48 h and 72 h. The viability and apoptosis of the SW1353 cells in the presence or absence of resveratrol were analyzed by CCK8 assay and Hoechst 33258 staining, respectively. The protein levels of Bcl-2, Bax, activated caspase-3, Akt and p-Akt were detected by Western blotting. The cell migration ability was determined by wound scratch assay. RESULTS：Exposure of the cells to resveratrol resulted in a decrease in the cell viability in a dose- and time-dependent manner (P<0.05). visible nuclei with apoptotic characteristics in resveratrol group were observed. The protein levels of activated caspase-3 and Bax were increased, and Bcl-2 and p-Akt were decreased compared with control group. The total Akt were not significantly changed. Resveratrol also significantly reduced the migration of tumor cells. CONCLUSION：Resveratrol induces apoptosis of chondrosarcoma, which plays a role of part through mitochondrial and PI3K/Akt signaling pathways.     

Effect of FSD-C10 on modulation of inflammatory microenvironment in an Alzheimer disease double transgenic mouse model

AIM: To explore the therapeutic effect of a novel Rho kinase inhibitor FSD-C10 on β-amyloid protein precursor (APP)/presenilin-1 (PS1) double transgenic mice. METHODS: The transgenic mice overexpressing human APP with the Swedish mutation (695) and human PS1 with ΔE9 mutation at the age of 8 months were used in this study. The mice were randomly divided into model group and FSD-C10 intervention group, and wild-type mice at the same age served as normal controls. The mice in FSD-C10 intervention group were treated with FSD-C10 (25 mg·kg^-1·d^-1) for 2 months by intraperitoneal injection. The mice in model group and the wild-type mice were injected with saline in the similar manner. Morris water maze (MWM) test was applied to examine the capacity of learning and memory. The Aβ_1-42 deposition, Tau protein phosphorylation, and the expression of β-site APP-cleaving enzyme (BACE) as well as inflammatory molecules, such as TLR-4 and NF-κB, and M1/M2 microglial markers, such as iNOS and Arg-1, were determined by the methods of immunohistochemistry and Western blot. RESULTS: Compared with model group, FSD-C10 significantly improved the learning and memory abilities of APP/PS1 double transgenic mice, accompanied by reduced Aβ_1-42 deposition, Tau protein phosphorylation and BACE expression in the hippocampus. The intervention of FSD-C10 decreased the protein levels of TLR-4 and p-NF-κB, reduced the expression of iNOS and increased the expression of Arg-1 in the brain tissues. CONCLUSION: The novel Rho kinase inhibitor FSD-C10 improves the capacity of spatial learning and memory in APP/PS1 double transgenic mice, which may be related to the inhibition of TLRs/NF-κB signaling pathway, the reduction of the secretion of inflammatory molecules and the polarization of anti-inflammatory M2 microglia, thus improving the inflammatory microenvironment of the brain in APP/PS1 double transgenic mice.     

ROCK promotes high glucose-induced cardiomyocyte apoptosis by inhi-biting PI3K/Akt signaling pathway

AIMTo investigate whether Rho-associated coiled-coil kinase (ROCK) is involved in high glucose-induced apoptosis of primary cardiomyocytes by regulating PI3K/Akt signaling pathway. METHODSPrimary Wistar rat cardiomyocytes were cultured and identified by α-sarcomeric actin (α-SCA) immunohistochemistry. Cardiomyocytes were treated with 5.5, 33 and 40 mmol/L glucose for 48 h. The cell viability was measured by MTT assay, and the mRNA expression of ROCK1 and ROCK2 in the cardiomyocytes was detected by RT-qPCR. Flow cytometry was used to analyze the apoptosis of the cardiomyocytes. The protein levels of ROCK1, ROCK2, cleaved caspase-3, Bcl-2, PI3K, Akt and p-Akt were determined by Western blot. In order to confirm the regulatory effect of ROCKs on PI3K/Akt signaling pathway, the cells were divided into control group (5.5 mmol/L glucose), high glucose group (33 mmol/L glucose) and high glucose+Y27632 (ROCK inhibitor) group. Western blot was used to detect the protein levels of ROCK1, ROCK2, PI3K, Akt and p-Akt. RESULTSAfter 48 h of high glucose exposure, the values of relative cell viability in 33 and 40 mmol/L glucose groups were (79.71±2.43)% and (68.41±7.49)%, respectively, both of which were significantly decreased compared with normal control group (P<0.05). After 48 h of high glucose exposure, the relative mRNA levels of ROCK1 and ROCK2 in 33 and 40 mmol/L glucose groups were significantly increased compared with normal control group (P<0.05). Compared with normal control group, the apoptotic rate in 33 and 40 mmol/L glucose groups was increased significantly (P<0.05). Compared with normal control group, the protein expression of ROCK1, ROCK2 and cleaved caspase-3 in 33 and 40 mmol/L glucose groups was increased (P<0.05), while the protein expression of Bcl-2 was decreased (P<0.05). No significant difference in the protein levels of PI3K and Akt among the 3 groups was observed, while the protein level of p-Akt in 33 and 40 mmol/L glucose groups was decreased compared with normal control group (P<0.05). Compared with high glucose group, the expression of ROCK1 and ROCK2 was decreased in high glucose+Y27632 group. No significant difference in the protein levels of PI3K and Akt among the 3 groups was observed. Compared with normal control group, the protein level of p-Akt in high glucose group was decreased, and the protein level of p-Akt in high glucose+Y27632 group was increased significantly compared with high glucose group. CONCLUSION Under high glucose environment, ROCK may reduce the level of p-Akt by inhibiting the PI3K/Akt signaling pathway, thus promoting the apoptosis of cardiomyocytes.     

Effects of platelet-rich plasma on chondrocyte apoptosis and NLRP3/IL-1β signaling pathway in rabbits with osteoarthritis

AIM To explore the effect of platelet-rich plasma (PRP) on rabbit osteoarthritis and its possible mechanism. METHODS The rabbits with knee osteoarthritis were prepared and then divided into model group, sodium hyaluronate (SH) group and PRP group, and another sham operation group was set up, with 6 rabbits in each group. The gross morphological changes of rabbit cartilage were observed. HE staining was used to evaluate the pathomorphological changes of the cartilage. TUNEL staining was used to detect the apoptosis of chondrocytes. The expression of nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3)/interleukin-1β （IL-1β） signaling pathway-related molecules was observed by immunohistochemical staining, and the protein levels of caspase-3, Bcl-2 and Bax were determined by Western blot. Chondrocytes were isolated and processed according to grouping, and the NLRP3 and IL-1β levels of the cells were measured by ELISA. RESULTS Compared with sham operation group, Pelletier score, Mankin score, chondrocyte apoptotic rate, the positive protein expression rates of NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), caspase-1 and IL-1β, and the protein levels of caspase-3 and Bax in model group were increased significantly (P<0.05), while the protein expression of Bcl-2 was decreased significantly (P<0.05). Compared with model group, Pelletier score, Mankin score, the apoptotic rate of chondrocytes, the positive protein expression rates of NLRP3, ASC, caspase-1 and IL-1β, and the protein levels of caspase-3 and Bax in SH group and PRP group were decreased significantly (P<0.05), while the protein expression of Bcl-2 was increased significantly (P<0.05). In PRP group, Pelletier score, Mankin score, the apoptotic rate of chondrocytes, the positive protein expression rates of NLRP3, ASC, caspase-1 and IL-1β, and the protein levels of caspase-3 and Bax were lower than those in SH group, while the protein expression of Bcl-2 was higher than that in SH group (P<0.05). Compared with control group, the expression of NL?RP3 and IL-1β in MCC950 (NLRP3 ihibitor) group were significantly reduced (P<0.05), the expression of NLRP3 in eucalyptol (IL-1β inhibitor) group was not significantly changed (P>0.05), and the expression of IL-1β was significantly reduced (P<0.05). CONCLUSION Platelet-rich plasma promotes the repair of cartilage in osteoarthritis rabbits, which has better effect than SH. The mechanism may be related to the inhibition of NLRP3/IL-1β pathway and the reduction of chondrocyte apoptosis.     

Shikonin induces apoptosis and autophagy of human cervical cancer HeLa cells by PI3K/Akt/mTOR signaling pathway

AIM:To observe the effects of shikonin on the apoptosis and autophagy of human cervical cancer HeLa cells, and to explore the possible role of PI3K/Akt/mTOR signaling pathway in these processes. METHODS:The HeLa cells were treated with shikonin, and the cell viability was detected by CCK-8 assay. The apoptosis was detected by Annexin V/PI double staining. The autophagosome was observed by transfection with GFP-LC3 into the HeLa cells. After the treatment with shikonin combined with autophagy inhibitor 3-methyladenine (3-MA) or apoptosis inhibitor Z-DEVD-FMK, the protein levels of autophagy-and apoptosis-related molecules microtuble-associated protein 1 light chain 3 (LC3) and cleaved caspase-3 in the HeLa cells were determined by Western blot. The protein levels of phosphorylated PI3K (p-PI3K), phosphorylated Akt (p-Akt) and phosphorylated mTOR (p-mTOR) were also determined by Western blot. RESULTS:Shikonin significantly inhibited the viability of HeLa cells (P<0.05). Compared with control group, shikonin significantly induced apoptosis of HeLa cells (P<0.05). The results of GFP-LC3 plasmid transfection analysis showed that green dot-like congregate autophagosomes appeared in the cytoplasm of the HeLa cells after shikonin treatment, while the autophagosomes were rarely observed in control group. Compared with shikonin group, LC3-Ⅱ/LC3-I was significantly decreased and cleaved caspase-3 was significantly increased in shikonin+3-MA group (P<0.05). Compared with shikonin group, LC3-Ⅱ/LC3-I was significantly increased and cleaved caspase-3 was significantly decreased in shikonin+Z-DEVD-FMK group (P<0.05). Compared with control group, shikonin significantly decreased the protein levels of p-PI3K, p-Akt and p-mTOR (P<0.05). CONCLUSION:The apoptosis and autophagy of the HeLa cells are induced by shikonin, these two processes are complementary. The mechanism may be related to inhibition of PI3K/Akt/mTOR signaling pathway.     

Molecular mechanism of BMSC intracerebral transplantation in improving learning and memory abilities of AD mice

AIM: To investigate the effect of bone marrow mesenchymal stem cell (BMSC) transplantation on learning and memory abilities and pathological changes of Alzheimer disease (AD) mice and the molecular mechanisms. METHODS: C57/BL6 wild-type (WT) and transgenic (Tg) mice were randomly divided into 4 groups:WT/PBS group, WT/BMSCs group, Tg/PBS group and Tg/BMSCs group. The mice were administered with PBS or BMSCs via intracerebroventricular injection. Spatial learning and memory abilities of the mice were evaluated by Morris water maze test on the 3rd day after surgery. Real-time PCR was applied to detect the mRNA expression of CX3C chemokine ligand 1 (CX3CL1), CX3C chemokine receptor 1 (CX3CR1), IL-1β, TNF-α, Nurr1, YM1, insulin-degrading enzyme (IDE) and matrix metalloproteinase 9 (MMP9). The protein levels of CX3CL1 and Aβ42 were measured by ELISA. Western blot was used to detect the protein expression of postsynaptic density protein 95 (PSD95) and synaptophysin (SYP). RESULTS: The transplanted BMSCs were observed near the hippocampus of APP/PS1 mice on the 10th postoperative day. The escape latency of the mice in Tg/PBS group was significantly longer than that in the WT/PBS mice (P<0.05). Compared with Tg/PBS group, the escape latency of Tg/BMSCs group was significantly shorter (P<0.05), and the mRNA and protein levels of CX3CL1 in Tg/BMSCs group were significantly higher than those in Tg/PBS group (P<0.01). The results of immunohistofluorescence staining showed that BMSC transplantation promoted the activation of microglia in the brain of WT and Tg mice. The mRNA expression of YM1 was up-regulated in WT/BMSCs group and Tg/BMSCs group (P<0.05). Compared with WT/PBS mice, the mRNA expression of TNF-α in the cortex and hippocampus of Tg/PBS group was significantly increased (P<0.05), and the mRNA expression of Nurr1 in the cortex was significantly decreased (P<0.01). Meanwhile, the mRNA expression of TNF-α in the cortex of Tg/BMSCs mice was decreased (P<0.01) and the mRNA expression of CX3CR1 and Nurr1 was up-regulated compared with Tg/PBS group (P<0.05). The results of Western blot showed that the protein levels of PSD95, p85, p110 and p-Akt in Tg/BMSCs group were significantly higher than those in Tg/PBS group (P<0.05). Finally, BMSC transplantation reduced the protein level of Aβ42 in APP/PS1 mice (P<0.05), and increased the mRNA expression of IDE and MMP9 in the hippocampus (P<0.05). CONCLUSION: BMSC transplantation modulates neuroinflammatory responses and promotes neuroprotective factor and synaptic protein expression, thus improving the learning and memory abilities in the APP/PS1 mice, which may be achieved by up-regulating the expression of CX3CL1.     

Effect of down-regulation of X-box binding protein 1 gene expression on viability and apoptosis of glioma cells

AIM: To investigate the effect of down-regulation of X-box binding protein 1 (XBP1) expression on the viability and apoptosis of glioma cells. METHODS: The mRNA expression of XBP1 in the glioma tissues was detected by qPCR. Small interfering RNA (siRNA) interfering with XBP1 expression (XBP1-siRNA) was transfected into human brain glioma U251 cells. At the same time, control group (the cells without special treatment) and negative control (NC-siRNA) group (transfected with siRNA without any interference) were set up. The mRNA expression of XBP1 in the 3 groups 48 h after transfection was detected by qPCR. The protein levels of XBP1, proliferating cell nuclear antigen (PCNA), B-cell lymphoma/leukemia-2 (Bcl-2), Bcl-2-associated X protein (Bax), cyclin D1 (cyclin D1), phosphatidylinositol 3-kinase (PI3K) and phosphorylated Akt (p-Akt) were determined by Western blot. The cell viability was measured by CCK-8 assay. The cell cycle distribution and apoptosis were analyzed by flow cytometry. RESULTS: The expression level of XBP1 in the glioma tissues was significantly higher than that in the tumor adjacent tissues (P<0.05). The XBP1 expression at mRNA and protein levels was significantly decreased in the cells transfected with XBP1-siRNA (P<0.05). No statistically significant difference of the cell viability, cell cycle, apoptotic rate and the protein levels of PCNA, Bcl-2, Bax, cyclin D1, PI3K and p-Akt between NC-siRNA group and control group was observed. Compared with control group, the cell viability, S-phase cells and the protein levels of PCNA, Bcl-2, cyclin D1, PI3K, and p-Akt in XBP1-siRNA group were decreased significantly, and the apoptotic rate, G₀/G₁-phase cells and Bax protein expression were significantly increased (P<0.05). CONCLUSION: Down-regulation of XBP1 gene expression in brain glioma cells reduces the viability of cancer cells, blocks the cells in G₁ phase and promote apoptosis. The mechanism is related to the inhibition of PI3K/Akt signaling pathway.     

Downregulation of DEK induces cell apoptosis via inhibition of NF-κB signaling pathway in gastric carcinoma SGC-7901 cells

AIM: To investigate the effect of DEK downregulation on the apoptosis of gastric carcinoma SGC-7901 cells, and to explore its associations with NF-κB signaling pathway and apoptosis related proteins. METHODS: SGC-7901 cells with different treatments were divided into 3 groups including untreated group, control siRNA group and DEK siRNA group. The expression of DEK at mRNA and protein levels in the SGC-7901 cells was detected by real-time PCR and Western blot. The cell apoptosis was examined by flow cytometry. Furthermore, the activities of caspase-3 and caspase-9 in the SGC-7901 cells were investigated by Caspase-Glo^®-3/9 kit. Finally, the expression of key regulatory protein p65 of NF-κB signaling pathway and apoptosis-related proteins Bcl-2 and Bax in the SGC-7901 cells was investigated by Western blot. RESULTS: Compared with untreated group and control siRNA group, the expression of DEK at mRNA and protein levels was significantly downregulated in DEK siRNA group (P<0.05). In addition, the ratios of early phase apoptosis and total apoptosis in DEK siRNA group were markedly higher than those in untreated group and control siRNA group (P<0.05). Most notably, the decrease in p65 and Bcl-2 proteins, increase in Bax protein and the increases of caspase-3 and caspase-9 activities were observed in DEK siRNA group. CONCLUSION: Downregulation of DEK mediates cell apoptosis of gastric carcinoma may be tightly associated with NF-κB signaling pathway.     

Relationship between histone H3K36 trimethylation and acute renal injury induced by ischemia/reperfusion

AIM: To observe the expression change of H3K36 trimethylation (H3K36me3) in acute kidney injury (AKI) induced by ischemia/reperfusion (IR) and analyze its correlation with SMYD2 and renal injury, and to provide a new target for clinical treatment of IR-AKI. METHODS: The ICR mice (n=30) were randomly divided into IR group (n=15) and sham operation group (sham group, n=15). The AKI model was established by clamping bilateral renal pedicles for 45 min. The serum and renal tissues of the mice were collected after the model was established for 24 h. The levels of blood urea nitrogen (BUN) and serum creatinine (SCr) were detected by biochemical method. The pathological changes of the kidney were observed by HE staining. The changes of NGAL and cleaved caspase-3 were observed by immunohistochemical (IHC) staining. The protein levels of NGAL, SMYD2, H3K36me3, p-P53, P53, cleaved caspase-3, Bax, Bcl-2, STAT3, p-STAT3, JNK and p-JNK1/2/3 in the renal tissues were determined by Western blot. The relationship between H3K36me3 and SMYD2/NGAL was analyzed by Pearson correlation method. RESULTS: Compared with sham group, BUN and SCr levels of the mice in IR group were significantly increased (P<0.05). HE staining showed significant edema, abscission and necrosis in renal tubular epithelial cells of the micc in IR group, and abscission of brush border and large amount of cell debris in the lumen were also observed. The IHC staining results showed that the protein levels of NGAL and cleaved caspase-3 in IR group were significantly increased. The results of Western blot showed that the protein levels of NGAL, SMYD2, H3K36me3, p-P53, cleaved caspase-3, Bax, STAT3, p-STAT3, JNK and p-JNK1/2/3 in IR group were significantly up-regulated (P<0.05), while the Bcl-2 levels were significantly down-regulated (P<0.05). The correlation analysis showed that H3K36me3 was positively correlated with the levels of SMYD2 and NGAL. CONCLUSION: H3K36me3 is closely related to SMYD2 and renal injury in IR-AKI mice, and the up-regulated expression of H3K36me3 may be involved in the regulation of IR-AKI occurrence and development together with the activation of STAT3 and JNK signaling pathways.     

Effects of matrine on apoptosis and related protein expression in human medulloblastoma D341 cells

AIM: To investigate matrine-induced apoptosis of human medulloblastoma D341 cells and the expression of Bax, Bcl-2, serine/threonine kinase Akt and phosphorylated Akt (p-Akt) in vitro. METHODS: D341 cells were divided into experimental groups (added with matrine at different concentrations) and control group (under the same conditions without matrine). The proliferation of D341 cells was analyzed by CCK-8 assay. Apoptosis was detected by Annexin V-FITC/PI double staining and the expression of Bax, Bcl-2, Akt and p-Akt was detected by Western blotting. RESULTS: Matrine significantly inhibited the proliferation of D341 cells and increased the apoptosis in a dose- and time-dependent manner. The cell apoptosis was characterized by chromatin condensation with margination of chromatin to the nuclear membrane, increased when and larger cytoplasmic vacuoles, and formation of apoptotic body after treatment with matrine. The expression of Bax increased, while the expression of Bcl-2 and p-Akt decreased when the drug concentration gradually increased. CONCLUSION: Matrine induces the apoptosis of human medulloblastoma D341 cells in vitro by activation of Bax, down-regulation of Bcl-2 and reduction of p-Akt expression level in the PI3K/Akt signaling pathway.     

Regulatory effect of miR-214-5p on myocardial injury and immune response in ischemia-reperfusion rats by targeting PAK4

AIM: To investigate the effect of microRNA-214-5p (miR-214-5p) on myocardial injury and immune response in rats with ischemia-reperfusion (I/R) by targeting p21-activated protein kinase 4 (PAK4). METHODS: The rats were divided into sham group, I/R group, Ad-Scramble group, and Ad-miR-214 group (n=9). Adenovirus was injected into 6 different sites on the anterior wall of the left ventricle of the rats. Four days later, the I/R model was constructed by suturing the left anterior descending coronary artery. The expression level of miR-214 was detected by RT-qPCR. Myocardial injury was observed by HE staining. The levels of heart damage markers (CK-MB, Mb, and cTnI) and inflammatory factors (IL-6, IL-1β and TNF-α) were measured by ELISA. The rate of cardiomyocyte apoptosis was analyzed by flow cytometry. The content of MDA and the activity of SOD were detected by commercially available kits. Target genes were predicted by genetic software and verified by dual-luciferase reporter assay. The protein levels of caspase-3, caspase-9, Bcl-2, Bax, PAK4, p-Akt and p-mTOR were determined by Western blot. RESULTS: miR-214 was down-regulated in the cardiomyocytes of I/R rats (P<0.01). Over-expression of miR-214-5p attenuated myocardial injury in the I/R rats, down-regulated the expression of CK-MB, Mb and cTnI, decreased the apoptotic rate of cardiomyocytes, up-regulated the expression of Bcl-2, down-regulated Bax, caspase-3 and caspase-9 expression, increased SOD activity, and decreased the content of MDA, IL-6, IL-1β and TNF-α (P<0.01). The binding sites of miR-214-5p and PAK4 were pre-sent in the 3’-UTR, and over-expression of miR-214-5p up-regulated the protein levels of PAK4, p-Akt and p-mTOR (P<0.01). CONCLUSION: miR-214-5p over-expression attenuates myocardial injury in I/R rats by targeting PAK4, inhibits cardiomyocyte apoptosis, oxidative stress and inflammation, and activates the PI3K/Akt/mTOR pathway.     

Effects of tangeretin on growth and invasion of human non-small-cell lung cancer cells

AIM: To study the influences of tangeretin (TGN) on the growth and invasion of non-small-cell lung cancer (NSCLC) cells, and to explore the molecular mechanisms. METHODS: The A549 cells were treated with different concentrations of TGN in vitro. The relative cell activity was determined by MTT assay. The apoptotic rate was analyzed by flow cytometry with Annexin V-FITC/PI staining. The number of the invasive cells was measured by Transwell assay. The mRNA expression of MMP-2 and MMP-9 was detected by RT-PCR, and the protein levels of Ki67, Cyt C, caspase-3, cleaved caspase-3, MMP-2, MMP-9, Akt, p-Akt and p-PI3K were determined by Western blotting analysis. RESULTS: TGN inhibited the proliferation of A549 cells in a dose-dependent manner (P<0.05) along with the low expression level of proliferation biomarker Ki67. TGN up-regulated the protein levels of Cyt C, caspase-3 and cleaved caspase-3 (P<0.01) and promoted the apoptosis of A549 cells in a dose-dependent manner. Moreover, TGN down-regulated the invasion-related molecules MMP-2 and MMP-9 at the mRNA and protein levels, and the number of invasive cells reduced with the increase in the concentration of TGN. The protein levels of p-Akt and p-PI3K in the A549 cells was reduced (P<0.05), and no difference of the cell viability in the cells treated with different concentrations of TGN was observed after blocking PI3K/Akt signaling pathway using LY294002. CONCLUSION: TGN inhibits the growth and invasion of A549 cells and promotes the cell apoptosis by potentially inhibiting PI3K/Akt signaling pathway activation. Therefore, this study will provide a new target for the prevention and control of NSCLC.     

Effects of berberine and yohimbine on splenocyte apoptosis in septic mice

AIM: To observe the effects of berberine and yohimbine on splenocyte apoptosis in septic mice and underlying mechanisms. METHODS: The mice were subjected to cecal ligature and puncture (CLP). The drugs or vehicle were given intragastrically 2 h after the surgery according to the following 5 groups: sham, CLP, CLP+berberine, CLP+yohimbine, and CLP+berberine+yohimbine. The apoptosis of splenocytes stained by TUNEL was observed under laser scanning confocal microscope 20 h after CLP. The splenic lymphocytes were isolated and observed using flow cytometry. The activities of caspase-3, caspase-8 and caspase-9 in splenic lymphocytes were detected, and the expression of Fas, Bim, Bcl-2 and Bax in the splenocytes was also determined by Western blotting. RESULTS: The TUNEL staining showed that the apoptotic rate of the splenocytes in septic mice 20 h after CLP was significantly higher than that in sham and CLP+yohimbine groups (P＜0.05). Compared with CLP group, the proportion of apoptotic cells was decreased in septic mice in CLP+berberine+yohimbine and CLP+yohimbine groups (P＜0.05). Flow cytometry analysis demonstrated the similar results in the apoptosis of splenocytes and T lymphocytes. However, only yohimbine treatment reduced the apoptosis of B lymphocytes in the spleen of sepsis-challenged mice. Compared with CLP group, caspase-9 activity was significantly reduced in CLP+berberine group (P＜0.05), the activities of caspase-3, caspase-8 and caspase-9 were all statistically reduced (P＜0.05) in CLP+yohimbine group and CLP+yohimbine+berberine group. CLP significantly increased the expression of cytosolic Fas, Bim and mitochondrial Bax in the splenocytes, and decreased Bcl-2 expression compared with sham group. Compared with CLP group, the expression of cytosolic Bim and mitochondrial Bax in CLP+berberine group were reduced (P＜0.05). Fas expression decreased only in CLP+yohimbine group (P＜0.05). Berberine combined with yohimbine reduced the expression of cytosolic Fas, Bim and mitochondrial Bax in the septic mouse splenocytes (P＜0.05).CONCLUSION: Yohimbine reduces sepsis-induced splenic lymphocyte apoptosis in mice by inhibiting Fas expression and in turn blocking both extrinsic and intrinsic apoptosis pathways. Berberine reduces Bim expression and inhibits caspase-9 activation, but not caspase-3 activation and apoptosis in the septic mouse splenocytes. Berberine combined with yohimbine reduces splenocyte apoptosis in the septic mice by inhibiting both extrinsic and intrinsic apoptotic pathways.     

Effect of growth arrest-specific protein 6 on H9c2 cell apoptosis induced by anoxia-reoxygenation via PI3K/Akt survival pathway

AIM: To investigate the effect of growth arrest-specific protein 6(Gas 6) on H9c2 cell apoptosis induced by anoxia-reoxygenation (A/R) and its possible relationship with PI3K/Akt pathway. METHODS: Cultured H9c2 cell line of cardiomyocytes was randomly divided into 4 groups: normal control group, anoxia-reoxygenation group (A/R), anoxia-reoxygenation+Gas6 group (A/R+Gas6) and anoxia/reoxygenation+Gas6+LY294002 group (A/R+Gas6+LY294002). The procedure of A/R was performed in cultured H9c2 cells by 3 h of anoxia and then 3 h of reoxygenation. The viability of the cells and the activity of caspase-3 were detected by automatic biochemistry analytic instrument. Cell apoptotic rates were evaluated by flow cytometry. The protein level of phosphorylated Akt(p-Akt) was determined by Western blotting. RESULTS: Compared with control group, the cell viability was significantly decreased, and caspase-3 activity, cell apoptotic rate and the protein level of p-Akt were increased in A/R group. Compared with A/R group, the caspase-3 activity and cell apoptotic rate reduced markedly, while the cell viability and the protein level of p-Akt were significantly increased in A/R+Gas6 group .The effect of Gas6 was inhibited by LY294002. CONCLUSION: Gas6 may protect the H9c2 cells from anoxia-reoxygenation-induced apoptosis. Its mechanism is possibly involved in the activation of PI3K/Akt survival pathway via increasing the phosphorylation of Akt protein.     

siRNA targeting TRIM29 gene induces apoptosis of nasopharyngeal carcinoma cells by inhibiting PI3K/AKT signaling pathway

AIM:To investigate the effect of TRIM29 gene expression silencing on the apoptosis and PI3K/AKT signaling pathway in human nasopharyngeal carcinoma 5-8F cells. METHODS:The 5-8F cells were divided into blank group, negative control (NC) group (transfected negative control siRNA) and si-TRIM29 group (transfected TRIM29 specific siRNA). The viability of the 5-8F cells transfected with si-TRIM29 for 0~96 h was measured by CCK-8 assay. The apoptotic rate and the protein levels of TRIM29, cleaved caspase-3, cleaved caspase-9, Bcl-2, Bax, t-AKT and p-AKT in the 5-8F cells transfected with si-TRIM29 for 48 h were determined by flow cytometry and Western blot, respectively. PI3K/AKT signal specific inhibitor LY294002 at 10 μmol/L and si-TRIM29 alone or in combination were treated with the 5-8F cells, and the cells were divided into blank group, LY294002 group and LY294002+si-TRIM29 group. The apoptotic rates in the 3 groups were detected by flow cytometry. RESULTS:The protein expression of TRIM29 in the 5-8F cells transfected with TRIM29 siRNA was significantly lower than that in blank group (P<0.05). Compared with blank group, the cell viability was significantly decreased, the apoptotic rate was significantly increased, the protein levels of cleaved caspase-3, cleaved caspase-9 and Bax were significantly increased, and the protein levels of Bcl-2 and p-AKT were significantly decreased in si-TRIM29 group (P<0.05). The apoptotic rate in LY294002 group was higher than that in blank group, while that in LY294002+si-TRIM29 group was even higher than that in LY294002 group (P<0.05). CONCLUSION:Silencing of TRIM29 gene expression induces apoptosis of nasopharyngeal carcinoma 5-8F cells by inhibiting PI3K/AKT signaling pathway.