Efficacy and safety of the long-acting fusion inhibitor albuvirtide in antiretroviral-experienced adults with human immunodeficiency virus-1: interim analysis of the randomized, controlled, phase 3, non-inferiority TALENT study / 中华医学杂志(英文版)

BACKGROUND@#Albuvirtide is a once-weekly injectable human immunodeficiency virus (HIV)-1 fusion inhibitor. We present interim data for a phase 3 trial assessing the safety and efficacy of albuvirtide plus lopinavir-ritonavir in HIV-1-infected adults already treated with antiretroviral drugs.@*METHODS@#We carried out a 48-week, randomized, controlled, open-label non-inferiority trial at 12 sites in China. Adults on the World Health Organization (WHO)-recommended first-line treatment for >6 months with a plasma viral load >1000 copies/mL were enrolled and randomly assigned (1:1) to receive albuvirtide (once weekly) plus ritonavir-boosted lopinavir (ABT group) or the WHO-recommended second-line treatment (NRTI group). The primary endpoint was the proportion of patients with a plasma viral load below 50 copies/mL at 48 weeks. Non-inferiority was prespecified with a margin of 12%.@*RESULTS@#At the time of analysis, week 24 data were available for 83 and 92 patients, and week 48 data were available for 46 and 50 patients in the albuvirtide and NRTI groups, respectively. At 48 weeks, 80.4% of patients in the ABT group and 66.0% of those in the NRTI group had HIV-1 RNA levels below 50 copies/mL, meeting the criteria for non-inferiority. For the per-protocol population, the superiority of albuvirtide over NRTI was demonstrated. The frequency of grade 3 to 4 adverse events was similar in the two groups; the most common adverse events were diarrhea, upper respiratory tract infections, and grade 3 to 4 increases in triglyceride concentration. Renal function was significantly more impaired at 12 weeks in the patients of the NRTI group who received tenofovir disoproxil fumarate than in those of the ABT group.@*CONCLUSIONS@#The TALENT study is the first phase 3 trial of an injectable long-acting HIV drug. This interim analysis indicates that once-weekly albuvirtide in combination with ritonavir-boosted lopinavir is well tolerated and non-inferior to the WHO-recommended second-line regimen in patients with first-line treatment failure.@*TRIAL REGISTRATION@#ClinicalTrials.gov Identifier: NCT02369965; https://www.clinicaltrials.gov.Chinese Clinical Trial Registry No. ChiCTR-TRC-14004276; http://www.chictr.org.cn/enindex.aspx.

Parathyroid hormone inhibits the apoptosis of osteoblast MC-3T3E1 cells through a non-PLC-dependent protein kinase C pathway / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of the non-PLC-dependent protein kinase C (PKC) pathway of parathyroid hormone (PTH) on the apoptosis and proliferation of osteoblast MC-3T3E1 cells.</p><p><b>METHODS</b>MC-3T3E1 cells were seeded in 96-well plates at the density of 1.5×10(4) cells/mL and incubated for 3 day. The cells were then exposed to 100 nmol/L of [Gly(1), Arg(19)]hPTH(1-28), 100 nmol/L of [Gly(1), Arg(19)]hPTH(1-34), 100 nmol/L of [Gly(1), Arg(19)]hPTH(1-34)+1 µmol/L Go6983, 1 µmol/L Go6983, or deionized water (control) for 1, 24 or 48 h. After the treatments, cell counting kit-8 (CCK-8) and Caspase-Glo® 3/7 Assay (Caspase-3) were used to examine the proliferation and apoptosis of MC3T3-E1 cells.</p><p><b>RESULTS</b>CCK-8 results showed that hPTH(1-34) increased the number of MC3T3-E1 cells compared with hPTH(1-34)+Go6983 at 1 h and 24 h, but this difference was not statistically different. At 48 h, treatment with hPTH(1-34), as compared with hPTH(1-28), significantly increased the number of MC3T3-E1 cells (P<0.05), and this effect was blocked by the PKC inhibitor Go6983 (P<0.05). hPTH(1-34) did not result in significant inhibition of MC3T3-E1 cell apoptosis at 1 h and 24 h as compared with hPTH(1-34)+Go6983, but significantly inhibited the cell apoptosis as compared with hPTH(1-28) (P<0.05); this inhibitory effect was blocked by Go6983 (P<0.05).</p><p><b>CONCLUSION</b>s A relatively long time (for 48 h) of exposure to PTH can inhibit apoptosis and promote the proliferation of MC3T3-E1cells through a non-PLC-dependent PKC pathway.</p>

Protein kinase C enhances the swelling-induced chloride current in human atrial myocytes / 华中科技大学学报（医学）（英德文版）

Swelling-activated chloride currents (ICl.swell) are thought to play a role in several physiologic and pathophysiologic processes and thus represent a target for therapeutic approaches. However, the mechanism of ICl.swell regulation remains unclear. In this study, we used the whole-cell patch-clamp technique to examine the role of protein kinase C (PKC) in the regulation of ICl.swell in human atrial myocytes. Atrial myocytes were isolated from the right atrial appendages of patients undergoing coronary artery bypass and enzymatically dissociated. ICl.swell was evoked in hypotonic solution and recorded using the whole-cell patch-clamp technique. The PKC agonist phorbol dibutyrate (PDBu) enhanced ICl.swell in a concentration-dependent manner, which was reversed in isotonic solution and by a chloride current inhibitor, 9-anthracenecarboxylicacid. Furthermore, the PKC inhibitor bis-indolylmaleimide attenuated the effect and 4α-PDBu, an inactive PDBu analog, had no effect on ICl.swell. These results, obtained using the whole-cell patch-clamp technique, demonstrate the ability of PKC to activate ICl,swell in human atrial myocytes. This observation was consistent with a previous study using a single-channel patch-clamp technique, but differed from some findings in other species.

Roles of PKCβ/P66Shc oxidative stress signal pathway in mediating hyperoxia-induced ROS production in alveolar epithelial cells / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To explore the roles of PKCβ/P66Shc oxidative stress signal pathway in mediating hyperoxia-induced reactive oxgen species (ROS) production in alveolar epithelial cells (A549) and the protective effects of PKCβ inhibitor on hyperoxia-induced injuries of alveolar epithelial cells.</p><p><b>METHODS</b>A549 cells were cultured in vitro and randomly divided into three groups: control, hyperoxia and PKCβ inhibitor LY333531 treatment. The hyperoxia group was exposed to a mixture of O2 (950 mL/L) and CO2 (50 mL/L) for 10 minutes and then cultured in a closed environment. The LY333531 group was treated with PKCβ inhibitor LY333531 of 10 µmol/L for 24 hours before hyperoxia induction. Cells were collected 24 hours after culture and the levels of PKCβ, Pin1, P66Shc and P66Shc-Ser36 were detected by Western blot. The intracellular translocation of P66Shc, the production of ROS and cellular mitochondria membrane potential were measured using the confocal microscopy.</p><p><b>RESULTS</b>Compared with the control group, the levels of PKCβ, Pin1, P66Shc and P-P66Shc-Ser36 in A549 cells 24 hours after culture increased significantly in the hyperoxia group. These changes in the hyperoxia group were accompanied with an increased translocation rate of P66Shc from cytoplasm into mitochondria, an increased production of mitochondrial ROS, and a reduced mitochondrial membrane potential. Compared with the hyperoxia group, the levels of Pin1, P66Shc and P66Shc-Ser36 in A549 cells, the translocation rate of P66Shc from cytoplasm into mitochondria and the production of mitochondrial ROS decreased significantly, while the mitochondrial membrane potential increased significantly in the LY333531 treatment group. However, there were significant differences in the above mentioned measurements between the LY333531 treatment and control groups.</p><p><b>CONCLUSIONS</b>Hyperoxia can increase the expression of PKCβ in alveolar epithelial cells and production of mitochondrial ROS and decrease mitochondrial membrane potential. PKCβ inhibitor LY333531 can partially disrupt these changes and thus alleviate the hyperoxia-induced alveolar epithelial cell injury.</p>

Activation of phospholipase C-independent protein kinase C signaling pathway of parathyroid hormone enhances CITED1 expression in mouse osteoblasts / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the functions of phospholipase C (PLC)-independent protein kinase C signaling pathway (PTH/nonPLC/PKC) of parathyroid hormone (PTH) and its role in bone metabolism.</p><p><b>METHODS</b>Osteoblasts isolated from the calvaria of 2- or 3-day-old C57BL mice, identified by alkaline phosphatase staining and Alizarin red staining, were treated for 4 h with 100 nmol/L [Gly(1), Arg(19)]hPTH(1-28) plus 10 nmol/L RP-cAMP, 10 nmol/L [Gly(1), Arg(19)]hPTH(1-34) plus 10 nmol/L RP-cAMP , 10 nmol/L PTH(1-34), or and 0.1% trifluoroacetic acid (TFA). The total RNA was then isolated for screening differentially expressed genes related to PTH/nonPLC/PKC pathway using Affymetrix mouse 12x135K gene expression profile microarray, and the identified genes were confirmed by real-time quantitative PCR. MC3T3-E1 cells treated with [Gly(1), Arg(19)]hPTH(1-28)+RP-cAMP, [Gly(1), Arg(19)]hPTH(1-34)+RP-cAMP, [Gly(1), Arg(19)]hPTH(1-34)+ RP-cAMP +100 nmol/L Go6983, or 0.1% TFA were also examined for GR(1-28)- or GR(1-34)-mediated gene expression changes using real-time quantitative PCR.</p><p><b>RESULTS</b>Alizarin red staining visualized red mineralized nodules in the osteoblasts at 28 days of culture. According to the genechip results, we selected 56 target genes related to PTH/nonPLC/PKC pathway, among which CITED1 showed higher expressions in [Gly(1), Arg(19)]hPTH(1-34)+ RP-cAMP group than in both the control group and [Gly(1), Arg(19)]hPTH(1-28)+RP-cAMP group (P<0.05), and its expression was the highest in PTH(1-34) group (P<0.05). RT-PCR of MC3T3-E1 cells yielded consist results with those in the primary osteoblasts, and the cells treated with Go6983 (a PKC inhibitor) did not show GR(1-28)- or GR(1-34)-mediated differential expression of CITED1.</p><p><b>CONCLUSION</b>The activation of PLC-independent protein kinase C signaling pathway of PTH enhances the expression of CITED1 in mouse osteoblasts to mediate the effect of PTH on bone metabolism, and this pathway is not dependent on the activation of PLC or PKA signaling.</p>

Role of glycogen synthase kinase 3β in maturation and function of murine myeloid dendritic cells in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the role of glycogen synthase kinase 3β (GSK-3β) in the maturation and function of murine bone marrow-derived dendritic cells (BMDCs).</p><p><b>METHODS</b>Mature DCs (mDCs) induced by LPS were examined for GSK-3β phosphorylation level with Western blotting before and after LPS exposure. To explore the role of GSK-3β in maturation and function of DCs, we added SB216763, a selective inhibitor of GSK-3β, in the cell culture of immature DCs (iDCs), and examined CD40 and CD86 expressions in the cells by flow cytometry and the expression of IL-6, IL-12 and IL-10 mRNA by real-time PCR; the changes of the immunogenicity of the cells was evaluated by mixed lymphocyte reaction. The expression of GSK-3β and RelB was examined by Western blotting in DC2.4 cells transfected with a lentiviral vector over-expressing murine GSK-3β gene.</p><p><b>RESULTS</b>LPS exposure significantly lowered GSK-3β activity in iDCs as demonstrated by increased Ser9 phosphorylation and reduced Tyr216 phosphorylation. GSK-3β inhibition induced DC maturation by increasing the expression of surface costimulatory molecules CD40 and CD86, lowered the expressions of IL-6 and IL-12 while enhanced the expression of IL-10 in iDCs, and impaired mixed lymphocyte reaction of the cells. In DC2.4 cells, lentivirus-mediated over-expression of GSK-3β obviously down-regulated the expression of RelB.</p><p><b>CONCLUSIONS</b>GSK-3β is a crucial enzyme involved in the differentiation and maintenance of an immature phenotype of DCs. GSK-3β is constitutively active in iDCs to inhibit their spontaneous maturation. DCs become phenotypically mature after inhibition of GSK-3β, which also executes a proinflammatory task in DC activation. The reduction of RelB protein levels as a result of GSK-3β overexpression supports GSK-3β as a new target for inducing tolerogenic DCs.</p>

Determination of drug antibody ratio in an antibody-drug conjugate / 药学学报

This paper reports the determination of the drug antibody ratio in an antibody-drug conjugate with two methods, i.e. LC-MS and UV/VIS, and to provide a reliable method to scientifically evaluate and effectively control the drug antibody ratio. Deglycosylated sample was analyzed with C4 column followed by MS, and the number of conjugated drugs in the antibody was determined by the molecular weight increase due to the addition of different number of drugs to the antibody, and then drug antibody ratio was calculated by weighted average of different number of drugs conjugated to the antibody. Optical density at 252 and 280 nm was measured with UV/VIS, and due to the difference of extinction coefficients between the antibody and the drug, the drug antibody ratio was calculated from linear equation with two unknowns. The drug antibody ratio was 3.21 and 3.25 respectively measured by the two methods, and the results were similar with the two methods. Our study indicated that both methods, LC-MS and UV/VIS, could be applied to the analysis of drug antibody ratio of the antibody drug conjugate.

Enhancement of GABA-activated currents by arginine vasopressin in rat dorsal root ganglion neurons / 生理学报

A growing number of studies have shown that arginine vasopressin (AVP) plays an analgesia role in the modulation of nociception. Previous studies have focused on the central mechanisms of AVP analgesia. The aim of the present study was to find out whether peripheral mechanisms are also involved. The effect of AVP on GABA-activated currents (IGABA) and GABAA receptor function in freshly isolated dorsal root ganglion (DRG) neurons of rats were studied using whole cell patch clamp technique. The result showed that, IGABA were potentiated by pre-treatment with AVP (1 × 10⁻¹⁰-1 × 10⁻⁵ mol/L) in a concentration-dependent manner. Meanwhile, the GABA concentration-response curve was shifted upwards, with an increase of (49.1 ± 4.0)% in the maximal current response but with no significant change in the EC50 values. These results indicate that the enhancing effect is non-competitive. In addition, the effects of AVP on IGABA might be voltage-independent. This potentiation of IGABA induced by AVP was almost completely blocked by the V1a receptor antagonist SR49059 (3 × 10⁻⁶ mol/L). Also it could be removed by intracellular dialysis of either GDP-β-S (5 × 10⁻⁴mol/L), a non-hydrolyzable GDP analog, or GF109203X (2 × 10⁻⁶ mol/L), a selective protein kinase C (PKC) inhibitor, with the re-patch clamp. These results suggest that AVP up-regulates the function of the GABAA receptor via G protein-coupled receptors and PKC-dependent signal pathways in rat DRG neurons, and this potentiation may underlie the analgesia induced by AVP.

Ruboxistaurin for the Treatment of Diabetic Peripheral Neuropathy: A Systematic Review of Randomized Clinical Trials

BACKGROUND: Diabetic peripheral neuropathy (DPN) is a common complication of diabetes mellitus. Protein kinase C (PKC) inhibitor's has been thought to be a potential disease modifying drug's in DPN as it slows or reverse neuropathy's progression. To assesses the efficacy and safety of ruboxistaurin on the progression of symptoms, signs, or functional disability in DPN. METHODS: A systematic review of the literature databases like PubMed, ProQuest, EBSCO, EMBASE, and Cochrane Central was performed up to August 2012. We included randomized controlled trials (RCTs) comparing PKC inhibitor ruboxistaurin (RBX) with control and lasting at least 6 months. Our primary outcome measure was change in neurological examination, measured by neurological total symptom score (NTSS) and vibration detection threshold (VDT). Secondary outcome measures were total quality of life (QoL), skin microvascular blood flow and others. RESULTS: Six RCTs were included in review. Change in neurological function assessed by NTSS was reported in six studies, out of which significant difference between the RBX and placebo group seen in four studies favouring treatment group while remaining two studies reported no significant difference. VDT was assessed in only one study in which no significant difference seen between RBX and placebo group. Two studies reported significant improvement in QoL data. Safety data was reported in only two studies in which none of side effect was related to RBX. CONCLUSION: RBX had effects on DPN in some studies, but the evidence is not enough for meta-analysis and firm conclusion.

Ruboxistaurin for the Treatment of Diabetic Peripheral Neuropathy: A Systematic Review of Randomized Clinical Trials

BACKGROUND: Diabetic peripheral neuropathy (DPN) is a common complication of diabetes mellitus. Protein kinase C (PKC) inhibitor's has been thought to be a potential disease modifying drug's in DPN as it slows or reverse neuropathy's progression. To assesses the efficacy and safety of ruboxistaurin on the progression of symptoms, signs, or functional disability in DPN. METHODS: A systematic review of the literature databases like PubMed, ProQuest, EBSCO, EMBASE, and Cochrane Central was performed up to August 2012. We included randomized controlled trials (RCTs) comparing PKC inhibitor ruboxistaurin (RBX) with control and lasting at least 6 months. Our primary outcome measure was change in neurological examination, measured by neurological total symptom score (NTSS) and vibration detection threshold (VDT). Secondary outcome measures were total quality of life (QoL), skin microvascular blood flow and others. RESULTS: Six RCTs were included in review. Change in neurological function assessed by NTSS was reported in six studies, out of which significant difference between the RBX and placebo group seen in four studies favouring treatment group while remaining two studies reported no significant difference. VDT was assessed in only one study in which no significant difference seen between RBX and placebo group. Two studies reported significant improvement in QoL data. Safety data was reported in only two studies in which none of side effect was related to RBX. CONCLUSION: RBX had effects on DPN in some studies, but the evidence is not enough for meta-analysis and firm conclusion.

Signaling Pathway of Lysophosphatidic Acid-Induced Contraction in Feline Esophageal Smooth Muscle Cells

Lysolipids such as LPA, S1P and SPC have diverse biological activities including cell proliferation, differentiation, and migration. We investigated signaling pathways of LPA-induced contraction in feline esophageal smooth muscle cells. We used freshly isolated smooth muscle cells and permeabilized cells from cat esophagus to measure the length of cells. Maximal contraction occurred at 10(-6) M and the response peaked at 30s. To identify LPA receptor subtypes in cells, western blot analysis was performed with antibodies to LPA receptor subtypes. LPA1 and LPA3 receptor were detected at 50 kDa and 44 kDa. LPA-induced contraction was almost completely blocked by LPA receptor (1/3) antagonist KI16425. Pertussis toxin (PTX) inhibited the contraction induced by LPA, suggesting that the contraction is mediated by a PTX-sensitive G protein. Phospholipase C (PLC) inhibitors U73122 and neomycin, and protein kinase C (PKC) inhibitor GF109203X also reduced the contraction. The PKC-mediated contraction may be isozyme-specific since only PKCepsilon antibody inhibited the contraction. MEK inhibitor PD98059 and JNK inhibitor SP600125 blocked the contraction. However, there is no synergistic effect of PKC and MAPK on the LPA-induced contraction. In addition, RhoA inhibitor C3 exoenzyme and ROCK inhibitor Y27632 significantly, but not completely, reduced the contraction. The present study demonstrated that LPA-induced contraction seems to be mediated by LPA receptors (1/3), coupled to PTX-sensitive G protein, resulting in activation of PLC, PKC-epsilon pathway, which subsequently mediates activation of ERK and JNK. The data also suggest that RhoA/ROCK are involved in the LPA-induced contraction.

Glycogen Synthase Kinase 3 Inactivation Induces Cell Senescence through Sterol Regulatory Element Binding Protein 1-Mediated Lipogenesis in Chang Cells

BACKGROUND: Enhanced lipogenesis plays a critical role in cell senescence via induction of expression of the mature form of sterol regulatory element binding protein 1 (SREBP1), which contributes to an increase in organellar mass, one of the indicators of senescence. We investigated the molecular mechanisms by which signaling molecules control SREBP1-mediated lipogenesis and senescence. METHODS: We developed cellular models for stress-induced senescence, by exposing Chang cells, which are immortalized human liver cells, to subcytotoxic concentrations (200 microM) of deferoxamine (DFO) and H2O2. RESULTS: In this model of stress-induced cell senescence using DFO and H2O2, the phosphorylation profile of glycogen synthase kinase 3alpha (GSK3alpha) and beta corresponded closely to the expression profile of the mature form of SREBP-1 protein. Inhibition of GSK3 with a subcytotoxic concentration of the selective GSK3 inhibitor SB415286 significantly increased mature SREBP1 expression, as well as lipogenesis and organellar mass. In addition, GSK3 inhibition was sufficient to induce senescence in Chang cells. Suppression of GSK3 expression with siRNAs specific to GSK3alpha and beta also increased mature SREBP1 expression and induced senescence. Finally, blocking lipogenesis with fatty acid synthase inhibitors (cerulenin and C75) and siRNA-mediated silencing of SREBP1 and ATP citrate lyase (ACL) significantly attenuated GSK3 inhibition-induced senescence. CONCLUSION: GSK3 inactivation is an important upstream event that induces SREBP1-mediated lipogenesis and consequent cell senescence.

Glycogen Synthase Kinase 3 Inactivation Induces Cell Senescence through Sterol Regulatory Element Binding Protein 1-Mediated Lipogenesis in Chang Cells

BACKGROUND: Enhanced lipogenesis plays a critical role in cell senescence via induction of expression of the mature form of sterol regulatory element binding protein 1 (SREBP1), which contributes to an increase in organellar mass, one of the indicators of senescence. We investigated the molecular mechanisms by which signaling molecules control SREBP1-mediated lipogenesis and senescence. METHODS: We developed cellular models for stress-induced senescence, by exposing Chang cells, which are immortalized human liver cells, to subcytotoxic concentrations (200 microM) of deferoxamine (DFO) and H2O2. RESULTS: In this model of stress-induced cell senescence using DFO and H2O2, the phosphorylation profile of glycogen synthase kinase 3alpha (GSK3alpha) and beta corresponded closely to the expression profile of the mature form of SREBP-1 protein. Inhibition of GSK3 with a subcytotoxic concentration of the selective GSK3 inhibitor SB415286 significantly increased mature SREBP1 expression, as well as lipogenesis and organellar mass. In addition, GSK3 inhibition was sufficient to induce senescence in Chang cells. Suppression of GSK3 expression with siRNAs specific to GSK3alpha and beta also increased mature SREBP1 expression and induced senescence. Finally, blocking lipogenesis with fatty acid synthase inhibitors (cerulenin and C75) and siRNA-mediated silencing of SREBP1 and ATP citrate lyase (ACL) significantly attenuated GSK3 inhibition-induced senescence. CONCLUSION: GSK3 inactivation is an important upstream event that induces SREBP1-mediated lipogenesis and consequent cell senescence.

Effects of glycogen synthase kinase 3β overexpression in rat and glycogen synthase kinase 3β inhibitor SB-216763 on proliferation of hepatic oval cells / 中华外科杂志

<p><b>OBJECTIVE</b>To research the effects of glycogen synthase kinase (GSK3β) overexpression and GSK3β inhibitor SB-216763 on the proliferation of hepatic oval cells in rats and its regulatory mechanisms by Wnt signaling pathway.</p><p><b>METHODS</b>The hepatic oval cells WBF-344 were divided into the blank control group, GSK3β over-expression group, DMSO control group and GSK3β inhibitor groups, while the inhibitor groups set up three concentration gradients, that was 1, 5, 10 µmol/L. Using the GSK3β over-expression lentivirus, which had been identified correctly, and SB-216763 dealt with the cells WBF-344. The cells morphology of each group was observed under the phase contrast inverted microscope, and the expression of fluorescence in the lentivirus-transfected group was observed under the fluorescent microscope. The proliferation of each group cells was tested by CCK8 kits. The cells' apoptosis was detected by AnnexinV-FITC/PI kits. The expression of GSK3β, β-catenin and cyclin D1 were detected by Western blot.</p><p><b>RESULTS</b>The cells of GSK3β over-expression group were fewer and obvious aging. However, in each inhibitor added group, the cells' division and proliferation was vigorous, and the condition was good. Moreover, the cells' proliferation was getting stronger with the concentration of SB-216763 increasing. A large number of green fluorescence was expressed in the lentivirus-transfected cells. The cells' proliferation in GSK3β over-expression group restrained (t = 7.178, P < 0.01, as compared with control), while the cells' proliferation was vigorous in inhibitor groups (F = 45.030, P < 0.01, as compared with control). Flow Cytometry showed that the cells apoptosis was significant in GSK3β over-expression group. Western blot showed that the expression of GSK3β was increased, while the expression of β-catenin and cyclin D1 was decreased in the over-expression group. The expression of GSK3β had no significant difference among the control group and inhibitor groups. However, the expression of β-catenin and cyclin D1 was significantly increased with the concentration of SB-216763 increasing.</p><p><b>CONCLUSIONS</b>The overexpression of GSK3β can inhibit the Wnt signaling pathway, thus restrain the cells' proliferation and promotes apoptosis. SB-216763 can activate the Wnt pathway, thus promotes cells' proliferation.</p>

Protective effect of protein kinase C inhibitor Ro-31-8425 on hyperpermeability of human umbilical vein endothelial cells exposed to high glucose in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of different concentrations of glucose on the permeability of human umbilical vein endothelial cell monolayer and the protective effect of protein kinase C (PKC) inhibitor Ro-31-8425 against high-glucose exposure.</p><p><b>METHODS</b>Cultured human umbilical vein endothelial cell line EA.hy926 cells were exposed to 5.5 mmol/L glucose (control) and high-concentration glucose (10, 15, 20, 25.5, and 30 mmol/L), and the endothelial monolayer permeability was assessed by measuring the flux of FITC-labeled dextran (FITC-DΧ) across the endothelial cells. The cultured EA.hy926 cells were treated with 5.5 mmol/L glucose +saline, high glucose (25.5 mmol/L) +saline, or high glucose (25.5 mmol/L) +Ro-31-8425(10 µmol/L), and the level of PKC phosphorylation and endothelial monolayer permeability were evaluated.</p><p><b>RESULTS</b>High glucose dose-dependently increased the permeability of the endothelial cell monolayer (P<0.01), and glucose at 25.5 mmol/L significantly increased the phosphorylation level of PKCα and PKCβ II in the cells (P<0.01). Treatment with 10 µmol/L Ro-31-8425 obviously attenuated high-glucose-induced PKCα and PKCβ II phosphorylation (P<0.01) as well as the increase of the cell monolayer permeability (P<0.01).</p><p><b>CONCLUSIONS</b>High glucose increases the hyperpermeability of human umbilical vein endothelial cell monolayer mediated by the phosphorylation of PKC, and the PKC inhibitor Ro-31-8425 can reverse such effects.</p>

Bisindoylmaleimide I enhances osteogenic differentiation

The Wnt/β-catenin and bone morphogenetic proteins (BMPs) pathways play important roles in controlling osteogenesis. Using a cell-based kinase inhibitor screening assay, we identified the compound bisindoylmaleimide I (BIM) as a potent agonist of the cytosolic β-catenin accumulation in preosteoblast cells. Through suppressing glycogen synthase kinase 3β enzyme activities, BIM upregulated β-catenin responsive transcription and extended duration of BMP initiated signal. Functional analysis revealed that BIM promoted osteoblast differentiation and bone formation. The treatment of human mesenchymal stem cells with BIM promoted osteoblastogenesis. Our findings provide a new strategy to regulate mesenchymal stem cell differentiation by integration of the cellular signaling pathways.

Multiple Signaling Molecules are Involved in Expression of CCL2 and IL-1beta in Response to FSL-1, a Toll-Like Receptor 6 Agonist, in Macrophages

TLR6 forms a heterodimer with TLR2 and TLR4. While proinflammatory roles of TLR2 and TLR4 are well documented, the role of TLR6 in inflammation is poorly understood. In order to understand mechanisms of action of TLR6 in inflammatory responses, we investigated the effects of FSL-1, the TLR6 ligand, on expression of chemokine CCL2 and cytokine IL-1beta and determined cellular factors involved in FSL-1-mediated expression of CCL2 and IL-1beta in mononuclear cells. Exposure of human monocytic leukemia THP-1 cells to FSL-1 resulted not only in enhanced secretion of CCL2 and IL-1beta, but also profound induction of their gene transcripts. Expression of CCL2 was abrogated by treatment with OxPAPC, a TLR-2/4 inhibitor, while treatment with OxPAPC resulted in partially inhibited expression of IL-1beta. Treatment with FSL-1 resulted in enhanced phosphorylation of Akt and mitogen-activated protein kinases and activation of protein kinase C. Treatment with pharmacological inhibitors, including SB202190, SP6001250, U0126, Akt inhibitor IV, LY294002, GF109203X, and RO318220 resulted in significantly attenuated FSL-1-mediated upregulation of CCL2 and IL-1beta. Our results indicate that activation of TLR6 will trigger inflammatory responses by upregulating expression of CCL2 and IL-1beta via TLR-2/4, protein kinase C, PI3K-Akt, and mitogen-activated protein kinases.

Activation of Akt/protein kinase B mediates the protective effects of mechanical stretching against myocardial ischemia-reperfusion injury

Akt/protein kinase B is a well-known cell survival factor and activated by many stimuli including mechanical stretching. Therefore, we evaluated the cardioprotective effect of a brief mechanical stretching of rat hearts and determined whether activation of Akt through phosphatidylinositol 3-kinase (PI3K) is involved in stretch-induced cardioprotection (SIC). Stretch preconditioning reduced infarct size and improved post-ischemic cardiac function compared to the control group. Phosphorylation of Akt and its downstream substrate, GSK-3beta, was increased by mechanical stretching and completely blocked by wortmannin, a PI3K inhibitor. Treatment with lithium or SB216763 (GSK-3beta inhibitors) before ischemia induction mimicked the protective effects of SIC on rat heart. Gadolinium (Gd3+), a blocker of stretch-activated ion channels (SACs), inhibited the stretch-induced phosphorylation of Akt and GSK-3beta. Furthermore, SIC was abrogated by wortmannin and Gd3+. In vivo stretching induced by an aorto-caval shunt increased Akt phosphorylation and reduced myocardial infarction; these effects were diminished by wortmannin and Gd3+ pretreatment. Our results showed that mechanical stretching can provide cardioprotection against ischemia-reperfusion injury. Additionally, the activation of Akt, which might be regulated by SACs and the PI3K pathway, plays an important role in SIC.

Extracellular Nucleotides Can Induce Chemokine (C-C motif) Ligand 2 Expression in Human Vascular Smooth Muscle Cells

To understand the roles of purinergic receptors and cellular molecules below the receptors in the vascular inflammatory response, we determined if extracellular nucleotides up-regulated chemokine expression in vascular smooth muscle cells (VSMCs). Human aortic smooth muscle cells (AoSMCs) abundantly express P2Y1, P2Y6, and P2Y11 receptors, which all respond to extracellular nucleotides. Exposure of human AoSMCs to NAD+ , an agonist of the human P2Y11 receptor, and NADP+ as well as ATP, an agonist for P2Y1 and P2Y11 receptors, caused increase in chemokine (C-C motif) ligand 2 gene (CCL2) transcript and CCL2 release; however, UPT did not affect CCL2 expression. CCL2 release by NAD+ and NADP+ was inhibited by a concentration dependent manner by suramin, an antagonist of P2-purinergic receptors. NAD+ and NADP+ activated protein kinase C and enhanced phosphorylation of mitogen-activated protein kinases and Akt. NAD(+)- and NADP(+)-mediated CCL2 release was significantly attenuated by SP6001250, U0126, LY294002, Akt inhibitor IV, RO318220, GF109203X, and diphenyleneiodium chloride. These results indicate that extracellular nucleotides can promote the proinflammatory VSMC phenotype by up-regulating CCL2 expression, and that multiple cellular elements, including phosphatidylinositol 3-kinase, Akt, protein kinase C, and mitogen-activated protein kinases, are involved in that process.

The function of protein kinase C in myocardial fibrosis / 药学学报

Myocardial fibrosis is the common results of the development of a variety of heart diseases which leads to extracellular matrix protein metabolic disorders and causes cardiac remodeling owing to cardiac fibroblasts proliferation, eventually results in malignant arrhythmia, heart failure, and even the occurrence of sudden cardiac death. Effective inhibition of myocardial remodeling could prevent the occurrence of sudden death. To know the protein kinase C (PKC) effective mechanism of regulation on myocardial fibrosis, a new therapeutic target for reversing myocardial remodeling might be provided.