基于PI3K/PKB通路研究EGCG对CVB3感染致病毒性心肌炎小鼠细胞凋亡的影响

细胞凋亡是造成病毒性心肌炎(VMC)发病过程中心肌损伤的重要因素;表没食子儿茶素没食子酸酯(EGCG)对缺血再灌注引起的细胞凋亡具有抑制作用,但是否抑制VMC发病过程中的心肌细胞凋亡尚不明确.因此,本研究将分析EGCG对VMC小鼠细胞凋亡的影响及分子机制.BALB/c小鼠随机分为对照组、VMC组(腹腔注射CVB3悬液造模)、VMC+EGCG组(腹腔注射CVB3悬液造模后腹腔注射EGCG)、VMC+EGCG+LY组(腹腔注射CVB3悬液造模后腹腔注射EGCG及P13K抑制剂LY294002).检测血清心肌损伤标志物肌钙蛋白I(cTnI)及乳酸脱氢酶(LDH),心肌中CVB3滴度及RNA表达、HE染色、凋亡基因及p-PI3K、p-PKB表达.结果显示,与对照组比较,VMC组血清cTnI、LDH含量、心肌中CVB3滴度及RNA表达、细胞凋亡率、cleaved caspase-3表达升高,心肌中Survivin、p-PI3K、p-PKB表达降低(P＜0.05);与VMC组比较,VMC+EGCG组血清cTnI、LDH含量及心肌中细胞凋亡率、cleaved caspase-3表达降低,心肌中Survivin、p-PI3K、p-PKB表达升高(P＜0.05),心肌中CVB3滴度及RNA表达无明显变化(P＞0.05);与VMC+EGCG组比较,VMC+EGCG+LY组血清cTnI、LDH含量、心肌中细胞凋亡率、cleaved caspase-3表达升高,心肌中Survivin、p-PI3K、p-PKB表达降低(P＜0.05),心肌中CVB3滴度及RNA表达无明显变化(P＞0.05).以上结果表明EGCG对VMC小鼠心肌细胞凋亡具有抑制作用且该作用与激活PI3K/PKB通路有关.     

Vascular Endothelial Growth Factor-Receptor 1 Inhibition Aggravates Diabetic Nephropathy through eNOS Signaling Pathway in db/db Mice

The manipulation of vascular endothelial growth factor (VEGF)-receptors (VEGFRs) in diabetic nephropathy is as controversial as issue as ever. It is known to be VEGF-A and VEGFR2 that regulate most of the cellular actions of VEGF in experimental diabetic nephropathy. On the other hand, such factors as VEGF-A, -B and placenta growth factor bind to VEGFR1 with high affinity. Such notion instigated us to investigate on whether selective VEGFR1 inhibition with GNQWFI hexamer aggravates the progression of diabetic nephropathy in db/db mice.While diabetes suppressed VEGFR1, it did increase VEGFR2 expressions in the glomerulus. Db/db mice with VEGFR1 inhibition showed more prominent features with respect to, albuminuria, mesangial matrix expansion, inflammatory cell infiltration and greater numbers of apoptotic cells in the glomerulus, and oxidative stress than that of control db/db mice. All these changes were related to the suppression of diabetes-induced increases in PI3K activity and Akt phosphorylation as well as the aggravation of endothelial dysfunction associated with the inactivation of FoxO3a and eNOS-NOx. In cultured human glomerular endothelial cells (HGECs), high-glucose media with VEGFR1 inhibition induced more apoptotic cells and oxidative stress than did high-glucose media alone, which were associated with the suppression of PI3K-Akt phosphorylation, independently of the activation of AMP-activated protein kinase, and inactivation of FoxO3a and eNOS-NOx pathway. In addition, transfection with VEGFR1 siRNA in HGECs also suppressed PI3K-Akt-eNOS signaling.In conclusion, the specific blockade of VEGFR1 with GNQWFI caused severe renal injury related to profound suppression of the PI3K-Akt, FoxO3a and eNOS-NOx pathway, giving rise to the oxidative stress-induced apoptosis of glomerular cells in type 2 diabetic nephropathy.     

Antinociceptive Effect of Tetrandrine on LPS-Induced Hyperalgesia via the Inhibition of IKKβ Phosphorylation and the COX-2/PGE2 Pathway in Mice

Tetrandrine (TET) is a bisbenzylisoquinoline alkaloid that is isolated from the Stephania Tetrandra. It is known to possess anti-inflammatory and immunomodulatory effects. We have shown that TET can effectively suppress the production of bacterial lipopolysaccharide (LPS)-induced inflammatory mediators, including cyclooxygenases (COXs), in macrophages. However, whether TET has an antinociceptive effect on LPS-induced hyperalgesia is unknown. In the present study, we investigated the potential antinociceptive effects of TET and the mechanisms by which it elicits its effects on LPS-induced hyperalgesia. LPS effectively evoked hyperalgesia and induced the production of PGE₂ in the sera, brain tissues, and cultured astroglia. TET pretreatment attenuated all of these effects. LPS also activated inhibitor of κB (IκB) kinase β (IKKβ) and its downstream components in the IκB/nuclear factor (NF)-κB signaling pathway, including COX-2; the increase in expression levels of these components was significantly abolished by TET. Furthermore, in primary astroglia, knockdown of IKKβ, but not IKKα, reversed the effects of TET on the LPS-induced increase in IκB phosphorylation, P65 phosphorylation, and COX-2. Our results suggest that TET can effectively exert antinociceptive effects on LPS-induced hyperalgesia in mice by inhibiting IKKβ phosphorylation, which leads to the reduction in the production of important pain mediators, such as PGE₂ and COX-2, via the IKKβ/IκB/NF-κB pathway.     

The Effects of Pharmacological Inhibition of Histone Deacetylase 3 (HDAC3) in Huntington’s Disease Mice

An important epigenetic modification in Huntington’s disease (HD) research is histone acetylation, which is regulated by histone acetyltransferase and histone deacetylase (HDAC) enzymes. HDAC inhibitors have proven effective in HD model systems, and recent work is now focused on functional dissection of the individual HDAC enzymes in these effects. Histone deacetylase 3 (HDAC3), a member of the class I subfamily of HDACs, has previously been implicated in neuronal toxicity and huntingtin-induced cell death. Hence, we tested the effects of RGFP966 ((E)-N-(2-amino-4-fluorophenyl)-3-(1-cinnamyl-1H-pyrazol-4-yl)acrylamide), a benzamide-type HDAC inhibitor that selectively targets HDAC3, in the N171-82Q transgenic mouse model of HD. We found that RGFP966 at doses of 10 and 25 mg/kg improves motor deficits on rotarod and in open field exploration, accompanied by neuroprotective effects on striatal volume. In light of previous studies implicating HDAC3 in immune function, we measured gene expression changes for 84 immune-related genes elicited by RGFP966 using quantitative PCR arrays. RGFP966 treatment did not cause widespread changes in cytokine/chemokine gene expression patterns, but did significantly alter the striatal expression of macrophage migration inhibitory factor (Mif), a hormone immune modulator associated with glial cell activation, in N171-82Q transgenic mice, but not WT mice. Accordingly, RGFP966-treated mice showed decreased glial fibrillary acidic protein (GFAP) immunoreactivity, a marker of astrocyte activation, in the striatum of N171-82Q transgenic mice compared to vehicle-treated mice. These findings suggest that the beneficial actions of HDAC3 inhibition could be related, in part, with lowered Mif levels and its associated downstream effects.     

三七皂苷R1 对肝纤维化大鼠TGF-beta1/Smad3信号的影响

目的:探讨SD大鼠肝纤维化后肝组织及血清中转化生长因子-β1(Transforming Growth Factor-β1,TGF-β1)及Smad3的表达和变化,以及三七皂苷R1对肝纤维化的保护作用。方法:72只健康雄性SD大鼠分为对照组、二甲基亚硝胺(NDMA)组和三七皂苷R1组,再按不同时间点分为1、2、4周,3个亚组,每个亚组8只动物。NDMA组采用NDMA 2 m L/kg腹腔注射,三七皂苷R1组同时静脉注射三七皂苷R1,剂量为100 mg/kg体重,对照组注射等量的生理盐水。在各组的不同时间点采用RT-PCR及ELISA技术检测肝组织及血清中TGF-β1、Smad3的表达及变化。结果:1、TGF-β1、Smad3 m RNA及蛋白在各组中均有表达。2、对照组各时间点比较均无统计学意义(P>0.05)。NDMA组中,随着损伤时间的延长,TGF-β1、Smad3 m RNA及蛋白的表达逐渐上调,且各时间点与对照组比较有统计学意义(P<0.05)。而三七皂苷R1组TGF-β1、Smad3 m RNA及蛋白在各时间点均较NDMA组表达下调,有统计学意义(P<0.05)。结论:1、TGF-β1/Smad3信号参与了肝纤维化的发生和发展过程,且随损伤的逐渐加重,表达越高。2、三七皂苷R1可降低肝组织中TGF-β1/Smad3信号的表达,减轻肝细胞的纤维化,发挥保护肝组织损伤的作用。     

Rho-Kinase Inhibition Ameliorates Metabolic Disorders through Activation of AMPK Pathway in Mice

Background

Metabolic disorders, caused by excessive calorie intake and low physical activity, are important cardiovascular risk factors. Rho-kinase, an effector protein of the small GTP-binding protein RhoA, is an important cardiovascular therapeutic target and its activity is increased in patients with metabolic syndrome. We aimed to examine whether Rho-kinase inhibition improves high-fat diet (HFD)-induced metabolic disorders, and if so, to elucidate the involvement of AMP-activated kinase (AMPK), a key molecule of metabolic conditions.

Methods and Results

Mice were fed a high-fat diet, which induced metabolic phenotypes, such as obesity, hypercholesterolemia and glucose intolerance. These phenotypes are suppressed by treatment with selective Rho-kinase inhibitor, associated with increased whole body O₂ consumption and AMPK activation in the skeletal muscle and liver. Moreover, Rho-kinase inhibition increased mRNA expression of the molecules linked to fatty acid oxidation, mitochondrial energy production and glucose metabolism, all of which are known as targets of AMPK in those tissues. In systemic overexpression of dominant-negative Rho-kinase mice, body weight, serum lipid levels and glucose metabolism were improved compared with littermate control mice. Furthermore, in AMPKα2-deficient mice, the beneficial effects of fasudil, a Rho-kinase inhibitor, on body weight, hypercholesterolemia, mRNA expression of the AMPK targets and increase of whole body O₂ consumption were absent, whereas glucose metabolism was restored by fasudil to the level in wild-type mice. In cultured mouse myocytes, pharmacological and genetic inhibition of Rho-kinase increased AMPK activity through liver kinase b1 (LKB1), with up-regulation of its targets, which effects were abolished by an AMPK inhibitor, compound C.

Conclusions

These results indicate that Rho-kinase inhibition ameliorates metabolic disorders through activation of the LKB1/AMPK pathway, suggesting that Rho-kinase is also a novel therapeutic target of metabolic disorders.     

Neuroprotective Effect of Piclamilast-Induced Post-Ischemia Pharmacological Treatment in Mice

Neurochemical Research - Various studies have evidenced the neuroprotective role of PDE4 inhibitors. However, whether PDE4 inhibitor, Piclamilast pharmacological post-treatment is protective during...     

Effect of Postnatal Myostatin Inhibition on Bite Mechanics in Mice

As a negative regulator of muscle size, myostatin (Mstn) impacts the force-production capabilities of skeletal muscles. In the masticatory system, measures of temporalis-stimulated bite forces in constitutive myostatin KOs suggest an absolute, but not relative, increase in jaw-muscle force. Here, we assess the phenotypic and physiologic impact of postnatal myostatin inhibition on bite mechanics using an inducible conditional KO mouse in which myostatin is inhibited with doxycycline (DOX). Given the increased control over the timing of gene inactivation in this model, it may be more clinically-relevant for developing interventions for age-associated changes in the musculoskeletal system. DOX was administered for 12 weeks starting at age 4 months, during which time food intake was monitored. Sex, age and strain-matched controls were given the same food without DOX. Bite forces were recorded just prior to euthanasia after which muscle and skeletal data were collected. Food intake did not differ between control or DOX animals within each sex. DOX males were significantly larger and had significantly larger masseters than controls, but DOX and control females did not differ. Although there was a tendency towards higher absolute bite forces in DOX animals, this was not significant, and bite forces normalized to masseter mass did not differ. Mechanical advantage for incisor biting increased in the DOX group due to longer masseter moment arms, likely due to a more anteriorly-placed masseter insertion. Despite only a moderate increase in bite force in DOX males and none in DOX females, the increase in masseter mass in males indicates a potentially positive impact on jaw muscles. Our data suggest a sexual dimorphism in the role of mstn, and as such investigations into the sex-specific outcomes is warranted.     

麦门冬汤加减方对特发性肺纤维化小鼠PI3K/AKT/mTOR通路的调控

摘要 目的：探讨麦门冬汤加减方对特发性肺纤维化小鼠转化生长因子-β1(Transforming growth factor-β1,TGF-β1)、平滑肌肌动蛋白(α-smooth muscle actin, α-SMA)、胶原I(Collagen type I, COL1A)表达的影响以及对PI3K/AKT/mTOR通路的调控作用。方法：将120只SPF级ICR小鼠随机分入空白组、模型组、吡菲尼酮组和麦门冬汤加减方组,用博来霉素(5 mg/kg)建立特发性肺纤维化模型,24 h后分别给予相应的药物治疗。吡菲尼酮组和麦门冬汤加减方组小鼠分别灌胃吡菲尼酮和中药麦门冬汤加减方,空白组和模型组小鼠灌胃生理盐水,各组均连续给药3周(21d)后取材。观察指标：各组小鼠的肺系数;肺组织病理变化;肺组织TGF-β1、α-SMA、COL1A的表达量(免疫组化);肺组织中α-SMA、COL1A、p-PI3K、p-AKT、mTOR的蛋白表达量(Western blot);肺组织中TGF-β1、α-SMA、COL1A的mRNA表达量(qPCR)。结果：模型组小鼠的肺系数显著增加,麦门冬汤加减方组肺系数显著降低;模型组小鼠肺组织中有较多炎性细胞浸润,胶原沉积明显,肺泡结构破坏严重,麦门冬汤加减方组小鼠肺组织病理改变较模型组明显减轻,胶原沉积大量减少,肺泡结构逐渐修复;麦门冬汤加减方组较模型组α-SMA、COL1A、TGF-β1的蛋白表达量显著降低(P＜0.01);麦门冬汤加减方组较模型组α-SMA、COL1A、p-PI3K、p-AKT、mTOR的蛋白表达量显著下调(P＜0.01);麦门冬汤加减方组较模型组α-SMA、COL1A、TGF-β1的mRNA表达量显著降低(P＜0.01)。结论：麦门冬汤加减方能有效改善博来霉素诱导的特发性肺纤维化,降低α-SMA、COL1A、TGF-β1的表达,可能是通过调控PI3K/AKT/mTOR信号通路,抑制上皮间充质转化,减少细胞外基质沉积而发挥作用。     

临床路径对短暂性脑缺血患者影响的ITS分析

目的 了解某医院实施临床路径改革对短暂性脑缺血发作（transient ischemic attack,TIA）患者药费、检查费和住院日的影响。方法 使用间断时间序列分析方法（ITS）分析方法对医院2012年12月至2015年5月TIA患者药费、检查费和住院日进行分析。结果 检查费、住院日显著性下降,药费下降但无统计学意义。结论 实施临床路径改革对缩短患者住院日和控制医疗费用具有积极作用。     

Activation of the PI3K/mTOR Pathway following PARP Inhibition in Small Cell Lung Cancer

Small cell lung cancer (SCLC) is an aggressive malignancy with limited treatment options. We previously found that PARP is overexpressed in SCLC and that targeting PARP reduces cell line and tumor growth in preclinical models. However, SCLC cell lines with PI3K/mTOR pathway activation were relatively less sensitive to PARP inhibition. In this study, we investigated the proteomic changes in PI3K/mTOR and other pathways that occur following PAPR inhibition and/or knockdown in vitro and in vivo. Using reverse-phase protein array, we found the proteins most significantly upregulated following treatment with the PARP inhibitors olaparib and rucaparib were in the PI3K/mTOR pathway (p-mTOR, p-AKT, and pS6) (p≤0.02). Furthermore, amongst the most significantly down-regulated proteins were LKB1 and its targets AMPK and TSC, which negatively regulate the PI3K pathway (p≤0.042). Following PARP knockdown in cell lines, phosphorylated mTOR, AKT and S6 were elevated and LKB1 signaling was diminished. Global ATP concentrations increased following PARP inhibition (p≤0.02) leading us to hypothesize that the observed increased PI3K/mTOR pathway activation following PARP inhibition results from decreased ATP usage and a subsequent decrease in stress response signaling via LKB1. Based on these results, we then investigated whether co-targeting with a PARP and PI3K inhibitor (BKM-120) would work better than either single agent alone. A majority of SCLC cell lines were sensitive to BKM-120 at clinically achievable doses, and cMYC expression was the strongest biomarker of response. At clinically achievable doses of talazoparib (the most potent PARP inhibitor in SCLC clinical testing) and BKM-120, an additive effect was observed in vitro. When tested in two SCLC animal models, a greater than additive interaction was seen (p≤0.008). The data presented here suggest that combining PARP and PI3K inhibitors enhances the effect of either agent alone in preclinical models of SCLC, warranting further investigation of such combinations in SCLC patients.     

Genetic Deficiency in Neprilysin or Its Pharmacological Inhibition Initiate Excessive Stress-Induced Alcohol Consumption in Mice

Both acquired and inherited genetic factors contribute to excessive alcohol consumption and the corresponding development of addiction. Here we show that the genetic deficiency in neprilysin [NEP] did not change the kinetics of alcohol degradation but led to an increase in alcohol intake in mice in a 2-bottle-free-choice paradigm after one single stress stimulus (intruder). A repetition of such stress led to an irreversible elevated alcohol consumption. This phenomenon could be also observed in wild-type mice receiving an orally active NEP inhibitor. We therefore elucidated the stress behavior in NEP-deficient mice. In an Elevated Plus Maze, NEP knockouts crossed more often the area between the arms, implicating a significant stronger stress response. Furthermore, such animals showed a decreased locomotor activity under intense light in a locomotor activity test, identifying such mice to be more responsive in aversive situations than their wild-type controls. Since the reduction in NEP activity itself does not lead to significant signs of an altered alcohol preference in mice but requires an environmental stimulus, our findings build a bridge between stress components and genetic factors in the development of alcoholism. Therefore, targeting NEP activity might be a very attractive approach for the treatment of alcohol abuse in a society with increasing social and financial stress.     

Inhibition of Mevalonate Pathway Prevents Adipocyte Browning in Mice and Men by Affecting Protein Prenylation

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Combination of PI3K/Akt Pathway Inhibition and Plk1 Depletion Can Enhance Chemosensitivity to Gemcitabine in Pancreatic Carcinoma

The prognosis of pancreatic cancer (PC) remains pessimistic because of the difficulty in early diagnosis as well as the little advance in chemotherapy. Although being the first-line chemotherapy drug for PC at present, gemcitabine still has some disadvantages, such as low drug sensitivity and significant side effects. Thus, how to further improve the sensitivity of PC cells to gemcitabine is still a difficult subject in the field of pancreatic cancer-treatment. Polo-like kinase 1 (Plk1) is closely related to poor outcome in many malignant tumors and its high expression is linked to chemoresistance in PC. As a downstream gene activated by PI3K/Akt signal pathway, we assumed that the targeted depletion of Plk1 could contribute to the chemosensitization induced by synergistic drug interaction of PI3K inhibitor LY294002 together with gemcitabine. To analyze effect of Plk1 in chemotherapy, we constructed two recombinant adenoviral vectors which carry enhanced green fluorescent protein (rAd-EGFP) and Plk1-shRNA (rAd-shPlk1), respectively. Both inhibition of PI3K/Akt signal pathway through PI3K inhibitor LY294002 and targeted depletion of Plk1 via recombinant adenoviral shRNA can cause chemosensitization, and the targeted depletion of Plk1 can enhance the chemosensitization of LY294002. Thus, the gene therapy like targeted depletion of Plk1 may create new perspectives for chemosensitization of PC.     

Dual Pharmacological Targeting of the MAP Kinase and PI3K/mTOR Pathway in Preclinical Models of Colorectal Cancer

Background

The activation of the MAPK and PI3K/AKT/mTOR pathways is implicated in the majority of cancers. Activating mutations in both of these pathways has been described in colorectal cancer (CRC), thus indicating their potential as therapeutic targets. This study evaluated the combination of a PI3K/mTOR inhibitor (PF-04691502/PF-502) in combination with a MEK inhibitor (PD-0325901/PD-901) in CRC cell lines and patient-derived CRC tumor xenograft models (PDTX).

Materials and Methods

The anti-proliferative effects of PF-502 and PD-901 were assessed as single agents and in combination against a panel of CRC cell lines with various molecular backgrounds. Synergy was evaluated using the Bliss Additivity method. In selected cell lines, we investigated the combination effects on downstream effectors by immunoblotting. The combination was then evaluated in several fully genetically annotated CRC PDTX models.

Results

The in vitro experiments demonstrated a wide range of IC₅₀ values for both agents against a cell line panel. The combination of PF-502 and PD-901 demonstrated synergistic anti-proliferative activity with Bliss values in the additive range. As expected, p-AKT and p-ERK were downregulated by PF-502 and PD-901, respectively. In PDTX models, following a 30-day exposure to PF-502, PD-901 or the combination, the combination demonstrated enhanced reduction in tumor growth as compared to either single agent regardless of KRAS or PI3K mutational status.

Conclusions

The combination of a PI3K/mTOR and a MEK inhibitor demonstrated enhanced anti-proliferative effects against CRC cell lines and PDTX models.     

HDAC Inhibition Elicits Myocardial Protective Effect through Modulation of MKK3/Akt-1

We and others have demonstrated that HDAC inhibition protects the heart against myocardial injury. It is known that Akt-1 and MAP kinase play an essential role in modulation of myocardial protection and cardiac preconditioning. Our recent observations have shown that Akt-1 was activated in post-myocardial infarction following HDAC inhibition. However, it remains unknown whether MKK3 and Akt-1 are involved in HDAC inhibition-induced myocardial protection in acute myocardial ischemia and reperfusion injury. We sought to investigate whether the genetic disruption of Akt-1 and MKK3 eliminate cardioprotection elicited by HDAC inhibition and whether Akt-1 is associated with MKK3 to ultimately achieve protective effects. Adult wild type and MKK3^−/−, Akt-1^−/− mice received intraperitoneal injections of trichostatin A (0.1mg/kg), a potent inhibitor of HDACs. The hearts were subjected to 30 min myocardial ischemia/30 min reperfusion in the Langendorff perfused heart after twenty four hours to elicit pharmacologic preconditioning. Left ventricular function was measured, and infarct size was determined. Acetylation and phosphorylation of MKK3 were detected and disruption of Akt-1 abolished both acetylation and phosphorylation of MKK3. HDAC inhibition produces an improvement in left ventricular functional recovery, but these effects were abrogated by disruption of either Akt-1 or MKK3. Disruption of Akt-1 or MKK3 abolished the effects of HDAC inhibition-induced reduction of infarct size. Trichostatin A treatment resulted in an increase in MKK3 phosphorylation or acetylation in myocardium. Taken together, these results indicate that stimulation of the MKK3 and Akt-1 pathway is a novel approach to HDAC inhibition -induced cardioprotection.