BACKGROUND: Autophagy of alveolar macrophages is a crucial process in ischemia/reperfusion injury-induced acute lung injury (ALI). Bone marrow-derived mesenchymal stem cells (BM-MSCs) are multipotent cells with the potential for repairing injured sites and regulating autophagy. This study was to investigate the influence of BM-MSCs on autophagy of macrophages in the oxygen-glucose deprivation/restoration (OGD/R) microenvironment and to explore the potential mechanism. METHODS: We established a co-culture system of macrophages (RAW264.7) with BM-MSCs under OGD/R conditions in vitro. RAW264.7 cells were transfected with recombinant adenovirus (Ad-mCherry-GFP-LC3B) and autophagic status of RAW264.7 cells was observed under a fluorescence microscope. Autophagy-related proteins light chain 3 (LC3)-I, LC3-II, and p62 in RAW264.7 cells were detected by Western blotting. We used microarray expression analysis to identify the differently expressed genes between OGD/R treated macrophages and macrophages co-culture with BM-MSCs. We investigated the gene heme oxygenase-1 (HO-1), which is downstream of the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) signaling pathway. RESULTS: The ratio of LC3-II/LC3-I of OGD/R treated RAW264.7 cells was increased (1.27 ± 0.20 vs. 0.44 ± 0.08, t = 6.67, P  < 0.05), while the expression of p62 was decreased (0.77 ± 0.04 vs. 0.95 ± 0.10, t = 2.90, P  < 0.05), and PI3K (0.40 ± 0.06 vs. 0.63 ± 0.10, t = 3.42, P  < 0.05) and p-Akt/Akt ratio was also decreased (0.39 ± 0.02 vs. 0.58 ± 0.03, t = 9.13, P  < 0.05). BM-MSCs reduced the LC3-II/LC3-I ratio of OGD/R treated RAW264.7 cells (0.68 ± 0.14 vs. 1.27 ± 0.20, t = 4.12, P  < 0.05), up-regulated p62 expression (1.10 ± 0.20 vs. 0.77 ± 0.04, t = 2.80, P  < 0.05), and up-regulated PI3K (0.54 ± 0.05 vs. 0.40 ± 0.06, t = 3.11, P  < 0.05) and p-Akt/Akt ratios (0.52 ± 0.05 vs. 0.39 ± 0.02, t = 9.13, P  < 0.05). A whole-genome microarray assay screened the differentially expressed gene HO-1, which is downstream of the PI3K/Akt signaling pathway, and the alteration of HO-1 mRNA and protein expression was consistent with the data on PI3K/Akt pathway. CONCLUSIONS Our results suggest the existence of the PI3K/Akt/HO-1 signaling pathway in RAW264.7 cells under OGD/R circumstances in vitro, revealing the mechanism underlying BM-MSC-mediated regulation of autophagy and enriching the understanding of potential therapeutic targets for the treatment of ALI.
Apoptosis ; Autophagy ; Bone Marrow ; Glucose ; Heme Oxygenase-1/metabolism* ; Macrophages/metabolism* ; Mesenchymal Stem Cells/metabolism* ; Oxygen ; Phosphatidylinositol 3-Kinase ; Phosphatidylinositol 3-Kinases/metabolism* ; Proto-Oncogene Proteins c-akt/metabolism* ; Signal Transduction

OBJECTIVE: To explore the mechanism of electroacupuncture (EA) in promoting recovery of the facial function with the involvement of autophagy, glial cell line-derived neurotrophic factor (GDNF), and phosphatidylinositol-3-kinase (PI3K)/mammalian target of rapamycin (mTOR) signaling pathway. METHODS: Seventy-two male Sprague-Dawley rats were randomly allocated into the control, sham-operated, facial nerve injury (FNI), EA, EA+3-methyladenine (3-MA), and EA+GDNF antagonist groups using a random number table, with 12 rats in each group. An FNI rat model was established with facial nerve crushing method. EA intervention was conducted at Dicang (ST 4), Jiache (ST 6), Yifeng (SJ 17), and Hegu (LI 4) acupoints for 2 weeks. The Simone's 10-Point Scale was utilized to monitor the recovery of facial function. The histopathological evaluation of facial nerves was performed using hematoxylin-eosin (HE) staining. The levels of Beclin-1, light chain 3 (LC3), and P62 were detected by immunohistochemistry (IHC), immunofluorescence, and reverse transcription-polymerase chain reaction, respectively. Additionally, IHC was also used to detect the levels of GDNF, Rai, PI3K, and mTOR. RESULTS: The facial functional scores were significantly increased in the EA group than the FNI group (P<0.05 or P<0.01). HE staining showed nerve axons and myelin sheaths, which were destroyed immediately after the injury, were recovered with EA treatment. The expressions of Beclin-1 and LC3 were significantly elevated and the expression of P62 was markedly reduced in FNI rats (P<0.01); however, EA treatment reversed these abnormal changes (P<0.01). Meanwhile, EA stimulation significantly increased the levels of GDNF, Rai, PI3K, and mTOR (P<0.01). After exogenous administration with autophagy inhibitor 3-MA or GDNF antagonist, the repair effect of EA on facial function was attenuated (P<0.05 or P<0.01). CONCLUSIONS EA could promote the recovery of facial function and repair the facial nerve damages in a rat model of FNI. EA may exert this neuroreparative effect through mediating the release of GDNF, activating the PI3K/mTOR signaling pathway, and further regulating the autophagy of facial nerves.
Rats ; Male ; Animals ; Rats, Sprague-Dawley ; Electroacupuncture ; Phosphatidylinositol 3-Kinase/metabolism* ; Facial Nerve Injuries/therapy* ; Phosphatidylinositol 3-Kinases/metabolism* ; Beclin-1 ; Glial Cell Line-Derived Neurotrophic Factor ; Signal Transduction ; TOR Serine-Threonine Kinases/metabolism* ; Autophagy ; Mammals/metabolism*

Phosphatidylinositol (PI) 3-kinase plays an important role in transducing the signals of various growth factor receptors. However, the regulatory mechanism of PI3-kinase activity by these growth factor receptors is not completely understood. Therefore, we attempted to clarify the regulatory mechanism of PI3-kinase using insulin and 3T3 L1 fibroblasts. Our results showed that insulin stimulated PI3-kinase activity seven-fold and concomitantly phosphorylated a p85 subunit at the tyrosine residue. However, this tyrosine phosphorylation was not significant in the activation of PI3-kinase as the PI3-kinase pulled down by the overexpressed GST-p85 fusion protein showed as high an activity as the immunoprecipitated one. The p110 subunit was phosphorylated at both serine and tyrosine residues without insulin treatment. Since the phosphorylation state was not changed by insulin. The results suggested that phosphorylation of the p110 subunit does not control PI3-kinase activity. Finally, it was shown that the insulin receptor substrate-1 (IRS-1) binding to PI3-kinase was not sufficient for full activation because the amount of IRS-1 pulled down by the GST-p85 fusion protein reached almost maximum, after incubation with insulin-treated cell lysates for 20 min, whereas PI3-kinase activity reached its maximum only after incubation for 5 h. All results suggest that the phosphorylation of p85 subunit at tyrosine residues and phosphorylation of p110 subunit at tyrosine or serine residues are not functionally significant in the regulation of PI3-kinase activity. They also suggest that P13-kinase is needed to bind to other protein(s) as well as the insulin receptor substrate-1 for full activation.
1-Phosphatidylinositol 3-Kinase/metabolism* ; 3T3 Cells ; Animal ; Enzyme Activation ; Fibroblasts/metabolism* ; Human ; Immunoblotting ; Insulin/pharmacology* ; Mice ; Phosphoproteins/metabolism ; Phosphorylation ; Receptor, Insulin/metabolism ; Time Factors

BACKGROUND AND OBJECTIVEInvasion and metastasis are the primary causes of death in patients with pulmonary carcinoma. The epidermal growth factor (EGF) stimulates A549 cells invasion greatly through activating ERK and PI3K-Akt signaling pathway. The aim of this study is to elucidate the inhibitory effect of Resveratrol on EGF-induced invasive ability of A549 cells in vitro and explore the molecular mechanism.

METHODSThe cytotoxicity of Resveratrol was evaluated by methyl thiazolyltetrazolium (MTT) assay. Then, the A549 cells were treated with EGF and non-cytotoxic concentration of Resveratrol. The cells' invasion were detected by Boyden chamber assay; MMP-2 activity was determined by gelatine zymography assay; the changes of the related proteins were detected by Western blot.

RESULTSResveratrol was not toxic to A549 cells at the concentration between 0 to 30 microM. The invasion ability of EGF-induced A549 cells was decreased after treatment with 20 microM resveratrol for 24 h, accompanied by the inhibition of MMP-2 secretion. And the levels of p-ERK1/2, PI3K (within 6 h) were suppressed too.

CONCLUSION20 microM Resveratrol inhibits A549 cells' invasion possibly through the suppression of the activation of ERK and PI3K-Akt signaling pathways, subsequently exerting inhibitory effect on MMP-2.

Adenocarcinoma ; metabolism ; Anticarcinogenic Agents ; pharmacology ; Blotting, Western ; Cell Line, Tumor ; Epidermal Growth Factor ; pharmacology ; Humans ; Lung Neoplasms ; metabolism ; Mitogen-Activated Protein Kinase 1 ; metabolism ; Mitogen-Activated Protein Kinase 3 ; metabolism ; Phosphatidylinositol 3-Kinases ; metabolism ; Signal Transduction ; drug effects ; Stilbenes ; pharmacology

Hepatitis B virus x gene product (HBx) is known to be a transactivator of transcriptional elements that regulate the expression of a variety of genes associated with the growth, differentiation, survival and the apoptosis of cells. However, the exact mechanism of the activation and inhibition of cellular events by HBx remains uncertain. The present study was designed to measure the effect of HBx, on the signal transduction pathways associated with intracellular Ca(2+)mobilization following HBx transfection in the stable Chang liver cells (CHL-X). Enhanced cell proliferation by HBx in CHL-X was confirmed by MTT assay and by the immunodetection of PCNA. The transactivation of AP-1 by HBx induced in CHL-X was inhibited by cyclosporin A (CsA), a mitochondrial Ca(2+)channel blocker and by BAPTA-AM, a cytosolic Ca(2+)blocker. Activation of the SAPK/JNK signaling pathway by HBx was evidenced by the increased phosphorylations of c-Jun (Ser63) and of JNK (Thr183/Tyr185). Increased phospho-Erk/Erk and phospho-Raf1/Raf in HBx-induced CHL-X indicated that HBx might stimulate the MAPK pathway. PI3K activity and cytosolic free Ca(2+)levels were elevated in HBx-induced CHL-X. These results imply that HBx transactivates both JNK and MAPK signal transduction pathways in association with the mobilization of cytosolic Ca(2+).
1-Phosphatidylinositol 3-Kinase/metabolism ; Calcium/*metabolism ; Calcium Signaling/*physiology ; Cell Division ; Hepatitis B Virus/*metabolism ; Human ; Liver/*metabolism ; Mitogen-Activated Protein Kinases/metabolism ; Trans-Activators/*metabolism ; Transcription Factor AP-1/metabolism

OBJECTIVE: To elucidate the underlying mechanism of Panax notoginseng saponin (PNS) on gastric epithelial cell injury and barrier dysfunction induced by dual antiplatelet (DA). METHODS: Human gastric mucosal epithelial cell (GES-1) was cultured and divided into 4 groups: a control, a DA, a PNS+DA and a LY294002+PNS+DA group. GES-1 apoptosis was detected by flow cytometry, cell permeability were detected using Transwell, level of prostaglandins E2 (PGE2), 6-keto-prostaglandin F1α (6-keto-PGF1α) and vascular endothelial growth factor (VEGF) in supernatant were measured by enzyme linked immunosorbent assay (ELISA), expression of phosphatidylinositide 3-kinase (PI3K), phosphorylated-PI3K (p-PI3K), Akt, phosphorylated-Akt (p-Akt), cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), glycogen synthase kinase-3β (GSK-3β) and Ras homolog gene family member A (RhoA) were measured by Western-blot. RESULTS: DA induced apoptosis and hyper-permeability in GES-1, reduced supernatant level of PGE2, 6-keto-PGF1α and VEGF (P<0.05). Addition of PNS reduced the apoptosis of GES-1 caused by DA, restored the concentration of PGE2, 6-keto-PGF1α and VEGF (P<0.05). In addition, PNS attenuated the alteration of COX-1 and COX-2 expression induced by DA, up-regulated p-PI3K/p-Akt, down-regulated RhoA and GSK-3β. LY294002 mitigated the effects of PNS on cell apoptosis, cell permeability, VEGF concentration, and expression of RhoA and GSK-3β significantly. CONCLUSIONS PNS attenuates the suppression on COX/PG pathway from DA, alleviates DA-induced GES-1 apoptosis and barrier dysfunction through PI3K/Akt/ VEGF-GSK-3β-RhoA network pathway.
Cyclooxygenase 1 ; Epithelial Cells/metabolism* ; Glycogen Synthase Kinase 3 beta ; Humans ; Panax notoginseng ; Phosphatidylinositol 3-Kinases/metabolism* ; Platelet Aggregation Inhibitors ; Proto-Oncogene Proteins c-akt/metabolism* ; Saponins/pharmacology* ; Vascular Endothelial Growth Factor A ; rhoA GTP-Binding Protein

At this time, brain tumor stem cells remain a controversial hypothesis while malignant brain tumors continue to present a dire prognosis of severe morbidity and mortality. Yet, brain tumor stem cells may represent an essential cellular target for glioma therapy as they are postulated to be the tumorigenic cells responsible for recurrence. Targeting oncogenic pathways that are essential to the survival and growth of brain tumor stem cells represents a promising area for developing therapeutics. However, due to the multiple oncogenic pathways involved in glioma, it is necessary to determine which pathways are the essential targets for therapy. Furthermore, research still needs to comprehend the morphogenic processes of cell populations involved in tumor formation. Here, we review research and discuss perspectives on models of glioma in order to delineate the current issues in defining brain tumor stem cells as therapeutic targets in models of glioma.
1-Phosphatidylinositol 3-Kinase/genetics/metabolism ; Animals ; Brain Neoplasms/genetics/*metabolism/*pathology/therapy ; Glioma/genetics/*metabolism/*pathology/therapy ; Humans ; Neoplastic Stem Cells/*metabolism/*pathology ; Receptors, Notch/genetics/metabolism ; Signal Transduction/genetics/physiology

Endothelin can affect the contractile properties of cardiacmyocyte, stimulate myocyte growth and myofibrillogenesis, and increase resistance to apoptosis by intracellular signaling pathways. This article briefly reviews the regulative effects of these signaling pathways including protein kinase C, mitogen activated protein kinase, and phosphoinositide 3'-OH kinase/protein kinase B.
Animals ; Endothelin-1 ; physiology ; Endothelins ; physiology ; Humans ; Mitogen-Activated Protein Kinases ; metabolism ; Myocardial Contraction ; drug effects ; Myocytes, Cardiac ; metabolism ; Phosphatidylinositol 3-Kinases ; metabolism ; Protein Kinase C ; metabolism ; Signal Transduction

PURPOSE: Proliferation of vascular smooth muscle cells (VSMCs) plays a crucial role in atherosclerosis. Rutin is a major representative of the flavonol subclass of flavonoids and has various pharmacological activities. Currently, data are lacking regarding its effects on VSMC proliferation induced by intermittent hyperglycemia. Here, we demonstrate the effects of rutin on VSMC proliferation and migration according to fluctuating glucose levels. MATERIALS AND METHODS: Primary cultures of male Otsuka Long-Evans Tokushima Fatty (OLETF) rat VSMCs were obtained from enzymatically dissociated rat thoracic aortas. VSMCs were incubated for 72 h with alternating normal (5.5 mmol/L) and high (25.0 mmol/L) glucose media every 12 h. Proliferation and migration of VSMCs, the proliferative molecular pathway [including p44/42 mitogen-activated protein kinases (MAPK), mitogen-activated protein kinase kinase 1/2 (MEK1/2), p38 MAPK, phosphoinositide 3-kinase (PI3K), c-Jun N-terminal protein kinase (JNK), nuclear factor kappa B (NF-kappaB), and Akt], the migratory pathway (big MAPK 1, BMK1), reactive oxygen species (ROS), and apoptotic pathway were analyzed. RESULTS: We found enhanced proliferation and migration of VSMCs when cells were incubated in intermittent high glucose conditions, compared to normal glucose. These effects were lowered upon rutin treatment. Intermittent treatment with high glucose for 72 h increased the expression of phospho-p44/42 MAPK (extracellular signal regulated kinase 1/2, ERK1/2), phospho-MEK1/2, phospho-PI3K, phospho-NF-kappaB, phospho-BMK1, and ROS, compared to treatment with normal glucose. These effects were suppressed by rutin. Phospho-p38 MAPK, phospho-Akt, JNK, and apoptotic pathways [B-cell lymphoma (Bcl)-xL, Bcl-2, phospho-Bad, and caspase-3] were not affected by fluctuations in glucose levels. CONCLUSION: Fluctuating glucose levels increased proliferation and migration of OLETF rat VSMCs via MAPK (ERK1/2), BMK1, PI3K, and NF-kappaB pathways. These effects were inhibited by the antioxidant rutin.
Animals ; Caspase 3/metabolism ; Cell Movement/*drug effects ; Cell Proliferation/*drug effects ; Flavonoids/*pharmacology ; Glucose/*metabolism/pharmacology ; JNK Mitogen-Activated Protein Kinases ; MAP Kinase Kinase 1 ; Male ; Mitogen-Activated Protein Kinase 3 ; Muscle, Smooth, Vascular/cytology/*drug effects/enzymology ; Myocytes, Smooth Muscle/metabolism ; NF-kappa B/metabolism ; Phosphatidylinositol 3-Kinases ; Protein Kinase Inhibitors/*pharmacology ; Rats ; Rats, Inbred OLETF ; Rats, Long-Evans ; Reactive Oxygen Species/metabolism ; Rutin/*pharmacology ; p38 Mitogen-Activated Protein Kinases/metabolism

Nitric oxide (NO) seems to play a pivotal role in the vascular endothelial growth factor (VEGF)-induced endothelial cell proliferation. This study was designed to investigate the role and intracellular signal pathway of endothelial nitric oxide synthase (eNOS) activation induced by VEGF. ECV 304 cells were treated with betaVEGF(165) and then cell proliferation, eNOS protein and mRNA expression levels were analyzed to elucidate the functional role of eNOS in cell proliferation induced by VEGF. After exposure of cells to betaVEGF(165) , eNOS activity and cell growth were increased by approximately two-fold in the betaVEGF(165) -treated cells compared to the untreated cells. In addition, VEGF stimulated eNOS expression at both the mRNA and protein levels in a dose-dependent manner. Phosphatidylinositol-3 kinase (PI-3K) inhibitors were used to assess PI-3K involvement in eNOS regulation. LY294002 was found to attenuate VEGF-stimulated eNOS expression. Wortmannin was not as effective as LY294002, but the reduction effect was detectable. Cells activated by VEGF showed increased ERK1/2 levels. Moreover, the VEGF-induced eNOS expression was reduced by the PD98059, MAPK pathway inhibitor. This suggests that eNOS expression might be regulated by PI-3K and the ERK1/2 signaling pathway. In conclusion, betaVEGF(165) induces ECV 304 cell proliferation via the NO produced by eNOS. In addition, eNOS may be regulated by the PI-3K or mitogen-activated protein kinase pathway.
1-Phosphatidylinositol 3-Kinase/*antagonists & inhibitors ; Cell Division/drug effects ; Cell Line ; Endothelial Growth Factors/*metabolism/pharmacology ; Endothelium, Vascular/cytology ; *Gene Expression Regulation, Enzymologic ; Lymphokines/*metabolism/pharmacology ; MAP Kinase Signaling System ; Mitogen-Activated Protein Kinase 1/*antagonists & inhibitors ; Mitogen-Activated Protein Kinase 3 ; Mitogen-Activated Protein Kinases/*antagonists & inhibitors ; Nitric Oxide Synthase/*genetics/metabolism ; Nitric Oxide Synthase Type III ; Signal Transduction ; Vascular Endothelial Growth Factor A ; Vascular Endothelial Growth Factors