Xihuang pills induce apoptosis in hepatocellular carcinoma by suppressing phosphoinositide 3-kinase/protein kinase- B/mechanistic target of rapamycin pathway

BACKGROUND The phosphoinositide 3-kinase/protein kinase-B/mechanistic target of rapamycin(PI3K/Akt/mTOR) signalling pathway is crucial for cell survival, differentiation, apoptosis and metabolism. Xihuang pills(XHP) are a traditional Chinese preparation with antitumour properties. They inhibit the growth of breast cancer, glioma, and other tumours by regulating the PI3K/Akt/mTOR signalling pathway. However, the effects and mechanisms of action of XHP in hepatocellular carcinoma(HCC) remain unclear. Regulation of the PI3K/Akt/mTOR signalling pathway effectively inhibits the progression of HCC. However, no study has focused on the XHPassociated PI3K/Akt/mTOR signalling pathway. Therefore, we hypothesized that XHP might play a role in inhibiting HCC through the PI3K/Akt/mTOR signalling pathway.AIM To confirm the effect of XHP on HCC and the possible mechanisms involved.METHODS The chemical constituents and active components of XHP were analysed using ultra-performance liquid chromatography-quadrupole time of flight mass spectrometry(UPLC-Q-TOF-MS). Cellbased experiments and in vivo xenograft tumour experiments were utilized to evaluate the effect of XHP on HCC tumorigenesis. First, SMMC-7721 cells were incubated with different concentrations of XHP(0, 0.3125, 0.625, 1.25, and 2.5 mg/mL) for 12 h, 24 h and 48 h. Cell viability was assessed using the CCK-8 assay, followed by an assessment of cell migration using a wound healing assay.Second, the effect of XHP on the apoptosis of SMMC-7721 cells was evaluated. SMMC-7721 cells were stained with fluorescein isothiocyanate and annexin V/propidium iodide. The number of apoptotic cells and cell cycle distribution were measured using flow cytometry. The cleaved protein and mRNA expression levels of caspase-3 and caspase-9 were detected using Western blotting and quantitative reverse-transcription polymerase chain reaction(RT-qPCR), respectively.Third, Western blotting and RT–qPCR were performed to confirm the effects of XHP on the protein and mRNA expression of components of the PI3K/Akt/mTOR signalling pathway.Finally, the effects of XHP on the tumorigenesis of subcutaneous hepatocellular tumours in nude mice were assessed.RESULTS The following 12 compounds were identified in XHP using high-resolution mass spectrometry:Valine, 4-gingerol, myrrhone, ricinoleic acid, glycocholic acid, curzerenone, 11-keto-β-boswellic acid, oleic acid, germacrone, 3-acetyl-9,11-dehydro-β-boswellic acid, 5β-androstane-3,17-dione, and 3-acetyl-11-keto-β-boswellic acid. The cell viability assay results showed that treatment with 0.625mg/mL XHP extract decreased HCC cell viability after 12 h, and the effects were dose-and timedependent. The results of the cell scratch assay showed that the migration of HCC cells was significantly inhibited in a time-dependent manner by the administration of XHP extract(0.625mg/mL). Moreover, XHP significantly inhibited cell migration and resulted in cell cycle arrest and apoptosis. Furthermore, XHP downregulated the PI3K/Akt/mTOR signalling pathway, which activated apoptosis executioner proteins(e.g., caspase-9 and caspase-3). The inhibitory effects of XHP on HCC cell growth were determined in vivo by analysing the tumour xenograft volumes and weights.CONCLUSION XHP inhibited HCC cell growth and migration by stimulating apoptosis via the downregulation of the PI3K/Akt/mTOR signalling pathway, followed by the activation of caspase-9 and caspase-3.Our findings clarified that the antitumour effects of XHP on HCC cells are mediated by the PI3K/Akt/mTOR signalling pathway, revealing that XHP may be a potential complementary therapy for HCC.

Human neural stem cell-derived extracellular vesicles protect against ischemic stroke by activating the PI3K/AKT/mTOR pathway

Human neural stem cell-derived extracellular vesicles exhibit analogous functions to their parental cells,and can thus be used as substitutes for stem cells in stem cell therapy,thereby mitigating the risks of stem cell therapy and advancing the frontiers of stem cell-derived treatments.This lays a foundation for the development of potentially potent new treatment modalities for ischemic stroke.However,the precise mechanisms underlying the efficacy and safety of human neural stem cell-derived extracellular vesicles remain unclear,presenting challenges for clinical translation.To promote the translation of therapy based on human neural stem cell-derived extracellular vesicles from the bench to the bedside,we conducted a comprehensive preclinical study to evaluate the efficacy and safety of human neural stem cell-derived extracellular vesicles in the treatment of ischemic stroke.We found that administration of human neural stem cell-derived extracellular vesicles to an ischemic stroke rat model reduced the volume of cerebral infarction and promoted functional recovery by alleviating neuronal apoptosis.The human neural stem cell-derived extracellular vesicles reduced neuronal apoptosis by enhancing phosphorylation of phosphoinositide 3-kinase,mammalian target of rapamycin,and protein kinase B,and these effects were reversed by treatment with a phosphoinositide 3-kinase inhibitor.These findings suggest that human neural stem cell-derived extracellular vesicles play a neuroprotective role in ischemic stroke through activation of phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin signaling pathway.Finally,we showed that human neural stem cell-derived extracellular vesicles have a good in vivo safety profile.Therefore,human neural stem cell-derived extracellular vesicles are a promising potential agent for the treatment of ischemic stroke.

Role of phosphoinositide 3-kinase in the pathogenesis of acute pancreatitis

A large body of experimental and clinical data supports the notion that inflammation in acute pancreatitis has a crucial role in the pathogenesis of local and systemic damage and is a major determinant of clinical severity. Thus, research has recently focused on molecules that can regulate the inflammatory processes, such as phosphoinositide 3-kinases (PI3Ks), a family of lipid and protein kinases involved in intracellular signal transduction. Studies using genetic ablation or pharmacologic inhibitors of different PI3K isoforms, in particular the class I PI3Kδ and PI3Kγ, have contributed to a greater understanding of the roles of these kinases in the modulation of inflammatory and immune responses. Recent data suggest that PI3Ks are also involved in the pathogenesis of acute pancreatitis. Activation of the PI3K signaling pathway, and in particular of the class IB PI3Kγ isoform, has a significant role in those events which are necessary for the initiation of acute pancreatic injury, namely calcium signaling alteration, trypsinogen activation, and nuclear factor-κB transcription. Moreover, PI3Kγ is instrumental in modulating acinar cell apoptosis, and regulating local neutrophil infiltration and systemic inflammatory responses during the course of experimental acute pancreatitis. The availability of PI3K inhibitors selective for specific isoforms may provide new valuable therapeutic strategies to improve the clinical course of this disease. This article presents a brief summary of PI3K structure and function, and highlights recent advances that implicate PI3Ks in the pathogenesis of acute pancreatitis.

Effects of small interfering RNA inhibit Class Ⅰ phosphoinositide 3-kinase on human gastric cancer cells

AIM: To investigate the effects of small interfering RNA (siRNA)-mediated inhibition of Class?I?phosphoinositide 3-kinase (Class?I?PI3K) signal transduction on the proliferation, apoptosis, and autophagy of gastric cancer SGC7901 and MGC803 cells.METHODS: We constructed the recombinant replication adenovirus PI3K(I)-RNA interference (RNAi)-green fluorescent protein (GFP) and control adenovirus NC-RNAi-GFP, and infected it into human gastric cancer cells. MTT assay was used to determine the growth rate of the gastric cancer cells. Activation of autophagy was monitored with monodansylcadaverine (MDC) staining after adenovirus PI3K(I)-RNAi-GFP and control adenovirus NC-RNAi-GFP treatment. Immunofluorescence staining was used to detect the expression of microtubule-associated protein 1 light chain 3 (LC3). Mitochondrial membrane potential was measured using the fluorescent probe JC-1. The expression of autophagy was monitored with MDC, LC3 staining, and transmission electron microscopy. Western blotting was used to detect p53, Beclin-1, Bcl-2, and LC3 protein expression in the culture supernatant.RESULTS: The viability of gastric cancer cells was inhibited after siRNA targeting to the Class?I?PI3K blocked Class?I?PI3K signal pathway. MTT assays revealed that, after SGC7901 cancer cells were treated with adenovirus PI3K(I)-RNAi-GFP, the rate of inhibition reached 27.48% ± 2.71% at 24 h, 41.92% ± 2.02% at 48 h, and 50.85% ± 0.91% at 72 h. After MGC803 cancer cells were treated with adenovirus PI3K(I)-RNAi-GFP, the rate of inhibition reached 24.39% ± 0.93% at 24 h, 47.00% ± 0.87% at 48 h, and 70.30% ± 0.86% at 72 h (P < 0.05 compared to control group). It was determined that when 50 MOI, the transfection efficiency was 95% ± 2.4%. Adenovirus PI3K(I)-RNAi-GFP (50 MOI) induced mitochondrial dysfunction and activated cell apoptosis in SGC7901 cells, and the results described here prove that RNAi of Class?I?PI3K induced apoptosis in SGC7901 cells. The results showed that adenovirus PI3K(I)-RNAi-GFP transfection induced punctate distribution of LC3 immunoreactivity, indicating increased formation of autophagosomes. The results showed that the basal level of Beclin-1 and LC3 protein in SGC7901 cells was low. After incubating with adenovirus PI3K(I)-RNAi-GFP (50 MOI), Beclin-1, LC3, and p53 protein expression was significantly increased from 24 to 72 h. We also found that Bcl-2 protein expression down-regulated with the treatment of adenovirus PI3K(I)-RNAi-GFP (50 MOI). A number of isolated membranes, possibly derived from ribosome-free endoplasmic reticulum, were seen. These isolated membranes were elongated and curved to engulf a cytoplasmic fraction and organelles. We used transmission electron microscopy to identify ultrastructural changes in SGC7901 cells after adenovirus PI3K(I)-RNAi-GFP (50 MOI) treatment. Control cells showed a round shape and contained normal-looking organelles, nucleus, and chromatin, while adenovirus PI3K(I)-RNAi-GFP (50 MOI)-treated cells exhibited the typical signs of autophagy.CONCLUSION: After the Class?I?PI3K signaling pathway has been blocked by siRNA, the proliferation of cells was inhibited and the apoptosis of gastric cancer cells was enhanced.

Phosphoinositide 3-Kinase/Akt and Nuclear Factor-κB Are Involved in Staphylococcus Aureus-induced Apoptosis in U937 Cells

Objective To explore the mechanisms involved in Staphylococcus aureus （S. aureus） invading human monocytic U937 cells. Methods S. aureus were added to U937 cells at multiplicity of infections （MOI） of 20：1 for 0, 15, 30, 60, and 90 minutes, respectively. Cell apoptosis was analyzed with Hoechst 33258 staining and Annexin V-fluorescein isothiocyanate （FITC）/propidium iodide （PI） flow cytometry analysis. Akt and nuclear factor-κB （NF-κB） activities were detected by Western blotting. Results Infection of U937 cells with S. aureus induced rapid cell death in a time-dependent manner, and the cells displayed characteristic features of apoptosis. S. aureus-induced apoptosis was associated with a prominent downregulation of activated （phosphorylated） Akt and NF-κB. The inhibition of phosphorylated Akt by LY294002 led to the inhibition of NF-κB in a dose-dependent manner. Inhibition of Akt with LY294002 caused further increase in apoptosis of U937 cells. Conclusions S. aureus can stimulate the apoptosis of U937 ceils. S. aureus induces apoptosis of U937 cells by inhibiting Akt-regulated NF-κB.

Phosphoinositide 3-kinase dependent modulation of morphine versus cocaine dependence involves activation of nischarin

OBJECTIVE Phosphoinositide 3-kinase(PI3K) activation was reported to participate in the development of effect of some drugs,such as morphine and cocaine dependence.We previous found nischarin is associated with the activation of PI3K.It is our great interest to investigate the involvement of nischarin in PI3K dependent modulation of morphine versus cocaine dependence.METHODS In order to study the role of nischarin in drug dependence and tolerance,nischarin knockout mice were used for our research.Effect of psychological dependence was studied by conditioned place preference(CPP),and the effect of physical dependence was tested by naloxone-precipitated withdrawal signs.Some brain tissues were harvested 24 h after the behavioral experiment for the further measurement.RESULTS PI3K specific inhibitor LY294002 significantly blocked the acquisition of morphine-induced CPP in wild-type mice,but had no effect on its expression.In comparison,LY294002 failed to block the acquisition of cocaine-induced CPP but inhibited the expression.Furthermore,we found naloxoneprecipitated withdrawal signs in the morphine dependent mice was inhibited by LY294002.Nischarin knockout in mice could abolish the effect of LY294002 on blocking the effects of morphine,but had no effect on cocaine.CONCLUSION PI3K activation is involved in the different phases of morphine and cocaine dependence,and nischarin plays an important role in the process.

Leptin Regulated Insulin Secretion via Stimulating IRS2-associated Phosphoinositide 3-kinase Activity in the isolated Rat Pancreatic Islets

To investigate the molecular mechanism of leptin regulating insulin secretion through determining the regulation of insulin secretion and the insulin receptor substrate (IRS)-2-associated phosphoinositide 3-kinase (PI3K) activity by leptin in the isolated rat pancreatic islets, pancreatic islets were isolated from male SD rats by the collagenase method. The purified islets were incubated with leptin 2 nmol/L for 1 h in the presence of 5.6 mmol/L or 11.1 mmol/L glucose. Insulin release was measured using radioimmunoassay. IRS-2-associated activity of PI3K was determined by immunoprecipitate assay and Western blot. The results showed that in the presence of 5.6 mmol/L glucose, leptin had no significant effect on both insulin secretion and IRS-2-associated PI3K activity, but in the presence of 11.1 mmol/L glucose, insulin release was significantly inhibited after the islets were exposed to leptin for 1 h (P<0.01). PI3K inhibitor wortmannin blocked the inhibitory regulation of leptin on insulin release (P<0.05). Western Blot assay revealed that 2 nmol/L leptin could significantly increase the IRS-2-associated activity of PI3K by 51.5 % (P<0.05) in the presence of 11.1 mmol/L glucose. It was concluded that Leptin could significantly inhibit insulin secretion in the presence of 11.1 mmol/L glucose by stimulating IRS-2-associated activity of PI3K, which might be the molecular mechanism of leptin regulating insulin secretion.

The cardioprotection induced by lipopolysaccharide involves phosphoinositide 3-kinase/Akt and high mobility group box 1 pathways

Objective： The mechanisms by which lipopolysaccharide （LPS） pretreatment induces cardioprotection following ischaemia/reperfusion （I/R） have not been fully elucidated. We hypothesized that activation of phosphoinositide 3-kinase （PI3K）/Akt and high mobility group box 1 （HMGBxl） signaling plays an important role in LPS-induced cardioprotection. Methods： In in vivo experiments, age- and weight- matched male C57BL/10Sc wild type mice were pretreated with LPS before ligation of the left anterior descending coronary followed by reperfusion. Infarction size was examined by triphenyltetrazolium chloride （TTC） staining. Akt, phospho-Akt, and HMGBxl were assessed by immunoblotting with appropriate primary antibodies. In situ cardiac myocyte apop- tosis was examined by the TdT-mediated dUTP nick-end labeling （TUNEL） assay. In an in vitro study, rat cardiac myoblasts （H9c2） were subdivided into two groups, and only one was pretreated with LPS. After pretreatment, the cells were transferred into a hypoxic chamber under 0.5% 02. Levels of HMGBxl were assessed by immunoblot. Results： In the in vivo experiment, pretreatment with LPS reduced the at risk infarct size by 70.6% and the left ventricle infarct size by 64.93% respectively. Pretreatment with LPS also reduced cardiac myocytes apoptosis by 39.1% after ischemia and reperfusion. The mechanisms of LPS induced cardioprotection involved increasing PI3K/Akt activity and decreasing expression of HMGBxl. In the in vitro study, pretreatment with LPS reduced the level of HMGBxl in H9c2 cell cytoplasm following hypoxia. Conclusion： The results suggest that the cardioprotection following I/R induced by LPS pretreatment involves PI3K/Akt and HMGBxl pathways.

Promoting axon regeneration in the central nervous system by increasing PI3-kinase signaling

Much research has focused on the PI3-kinase and PTEN signaling pathway with the aim to stimulate repair of the injured central nervous system.Axons in the central nervous system fail to regenerate,meaning that injuries or diseases that cause loss of axonal connectivity have life-changing consequences.In 2008,genetic deletion of PTEN was identified as a means of stimulating robust regeneration in the optic nerve.PTEN is a phosphatase that opposes the actions of PI3-kinase,a family of enzymes that function to generate the membrane phospholipid PIP_(3) from PIP_(2)(phosphatidylinositol(3,4,5)-trisphosphate from phosphatidylinositol(4,5)-bisphosphate).Deletion of PTEN therefore allows elevated signaling downstream of PI3-kinase,and was initially demonstrated to promote axon regeneration by signaling through mTOR.More recently,additional mechanisms have been identified that contribute to the neuron-intrinsic control of regenerative ability.This review describes neuronal signaling pathways downstream of PI3-kinase and PIP3,and considers them in relation to both developmental and regenerative axon growth.We briefly discuss the key neuron-intrinsic mechanisms that govern regenerative ability,and describe how these are affected by signaling through PI3-kinase.We highlight the recent finding of a developmental decline in the generation of PIP_(3) as a key reason for regenerative failure,and summarize the studies that target an increase in signaling downstream of PI3-kinase to facilitate regeneration in the adult central nervous system.Finally,we discuss obstacles that remain to be overcome in order to generate a robust strategy for repairing the injured central nervous system through manipulation of PI3-kinase signaling.

七氟烷激活PI_3-K/Akt/P^(70S6K)信号转导通路抑制缺血/再灌注损伤神经元的凋亡

目的研究七氟烷对神经元缺血/再灌注损伤后PI3-K/Akt/P70S6K信号转导通路的影响,探讨七氟烷脑保护机制。方法将96孔和6孔培养板上培养7d的海马神经元随机分为6组:正常培养组(C组)、缺血/再灌注组(I/R组)、缺血/再灌注+2%Sevoflurane组(Sevo组)、缺血/再灌注+2%Sevoflurane+10μmol.L-1LY294002(PI3-K拮抗剂)组(LY组)、缺血/再灌注+2%Sevoflurane+10μmol.L-1Tric irib in(Akt拮抗剂)组(Tri组)、缺血/再灌注+2%Sevoflurane+10 nmol.L-1Rapamyc in(P70S6K拮抗剂)组(Rap组)。C组神经元按正常培养方法培养。Sevo组在神经元缺糖缺氧的同时接受2%Sevoflurane麻醉。LY组、Tri组和Rap组在神经元进行缺糖同时分别加入LY294002、Tric irib in或Rapamyc in使其终浓度分别为10μmol.L-1、10μmol.L-1或10 nmol.L-1后同Sevo组处理。96孔培养板的神经元进行细胞存活力的检测。6孔培养板的神经元进行神经元纯度鉴定、神经元凋亡和PI3-K、Akt和P70S6K蛋白表达的检测。结果Sevo组PI3K、Akt、P70S6K蛋白表达增加,神经元存活率增加、神经元凋亡率降低(vsI/R组,P<0.01)。LY组PI3K、Akt和P70S6K表达降低,神经元存活率降低、神经元凋亡率增加(vsSevo组,P<0.05或P<0.01);Tri组Akt和P70S6K表达降低,神经元存活率降低、神经元凋亡率增加(vsSevo组,P<0.05或P<0.01);Rap组P70S6K表达降低,神经元存活率降低、神经元凋亡率增加(vsSevo组,P<0.01)。结论Sevoflurane激活了PI3-K/Akt/P70S6K信号通路,在海马神经元缺血/再灌注损伤过程中抑制了神经元凋亡,保护了神经元。

一种新的瘦素抵抗机制:非酒精性脂肪肝瘦素/PI3-K/Akt信号通路的激活缺陷

目的:研究瘦素、瘦素受体(obesity receptor,OB-R)以及PI3-K/Akt信号通路在非酒精性脂肪肝(nonalcoholic fatty liver disease,NAFLD)患者体内的表达.方法:应用免疫组织化学方法研究30例NAFLD患者及对照组肝组织中瘦素,OB-R,PI3-K(p85)及Akt的表达以及其相关性.同时检测空腹血糖、总胆固醇、甘油三酯、C肽和血清瘦素水平等.结果:NAFLD患者肝组织中瘦素,OB-R和PI3-K显著高于对照组(P<0.05),且与血清瘦素水平成正相关.NAFLD患者肝组织中Akt的表达显著低于对照组(P<0.05).此外,PI3-K的表达与瘦素(r=0.365,P<0.05)呈正相关,但与Akt呈负相关(r=-0.854,P<0.01).结论:瘦素的过度表达不能活化NAFLD患者的Akt,瘦素/PI3-K激活Akt的缺陷可能是NAFLD患者瘦素抵抗的一种新机制.

壮骨镇痛胶囊含药血浆培养乳腺癌细胞rac-1,PI3-K转录和细胞伪足的变化

背景:前期实验已证实壮骨镇痛胶囊能显著抑制体外培养乳腺癌细胞的迁移和增殖。目的:进一步观察壮骨镇痛胶囊对高转移人乳腺癌MDA-MB-231细胞rac-1,PI3-K转录和细胞伪足生长的影响。方法:SD大鼠以3倍剂量灌服壮骨镇痛胶囊连续7d,以大鼠含药血浆培养MDA-MB-231细胞24h后,采用扫描电镜法观察不同浓度壮骨镇痛胶囊含药血浆对MDA-MB-231细胞伪足生长的影响,采用RT-PCR法检测含药血浆对MDA-MB-231细胞中rac-1,PI3-K转录的影响。结果与结论:5.0%和1.25%壮骨镇痛胶囊含药血浆能显著抑制MDA-MB-231细胞伪足的形成和生长以及rac-1和PI3-K基因的转录(P<0.05);0.63%壮骨镇痛胶囊含药血浆对伪足生长和rac-1基因转录无显著影响,但可显著抑制了PI3-K基因的转录(P<0.05)。由此推测壮骨镇痛胶囊含药血浆抑制MDA-MB-231细胞迁移可能与其抑制rac-1和PI3-K基因转录进而影响细胞伪足形成和生长密切有关,并且该作用可能与浓度相关。

PI3-K对自发性糖尿病大鼠心肌细胞膜GLUT4含量的影响

目的:探讨PI3-K在自发性糖尿病大鼠心肌细胞胰岛素抵抗中的作用。方法:①从大鼠心肌组织中抽提纯化总RNA,逆转录合成两组动物的cDNA及cRNA探针,与基因表达谱芯片杂交,扫描并分析统计;②分离培养大鼠心肌细胞,分别加入胰岛素及PI3-K特异性抑制剂LY294002,提取细胞膜蛋白,应用western-blot方法检测心肌细胞膜GLUT4含量的差异。结果:①PI3-K调节亚基基因下调表达达8倍,②胰岛素组应用LY294002后,细胞膜GLUT4表达量仅为抑制前的11.16%。结论:自发性糖尿病大鼠心肌存在胰岛素利用障碍,其关键部位在于PI3-K。

H_2S通过cAMP介导PI_3-K/Akt/P^(70S6K)通路抑制缺氧/复氧后神经元的凋亡

目的:研究H2S对缺氧/复氧后神经元存活信号转导通路PI3-K/Akt/P70S6K的影响。方法:取96孔和6孔培养板上培养7d的海马神经元,正常培养组(C组)神经元按正常培养方法培养。NaHS组在进行缺氧/复氧时加入NaHS使其终浓度为150μmol/L。Tri组、Rap组和Tri+Rap组在加入150μmol/LNaHS的同时分别加入triciribin10μmol/L、rapamycin10nmol/L或triciribin10μmol/L+rapamycin10nmol/L。96孔培养板的神经元进行细胞存活力的检测。6孔培养板的神经元进行神经元纯度鉴定、神经元凋亡、cAMP和PI3-K、Akt和P70S6K蛋白表达的检测。结果:NaHS显著增加了cAMP的浓度和PI3K、Akt、P70S6K蛋白的表达,同时增加了神经元存活率、降低了神经元凋亡率(P<0.01vsC组和A/R组)。Triciribin抑制了Akt和P70S6K表达同时降低了神经元存活率、升高了神经元凋亡率(P<0.05,P<0.01vsNaHS组)。Rapamycin抑制了P70S6K表达同时降低了神经元存活率、升高了神经元凋亡率(P<0.05,P<0.01vsNaHS组)。结论:H2S通过cAMP激活了PI3-K/Akt/P70S6K信号通路,抑制缺氧/复氧后海马神经元的凋亡。

失荅剌知丸对脑缺血大鼠再灌注后神经功能缺损及脑组织PI3-K和AKT表达的影响

目的探讨失荅剌知丸对脑缺血大鼠再灌注后神经功能缺损恢复程度以及皮质缺血周围区磷脂酰肌醇-3-激酶(PI3-K)和丝氨酸/苏氨酸蛋白激酶(AKT)表达的影响。方法 169只SD雄性大鼠随机分为假手术组、模型组、金纳多组(阳性药物对照组)和失荅剌知丸组,后3组采用线栓法制备大脑中动脉闭塞(MCAO)模型,缺血2h后再灌注,术后分12h、24h、72h、7d组,共13组,每组13只。采用Zea Longa评分法分别观察神经功能缺损恢复程度;TUNEL法检测24h脑细胞凋亡情况;免疫组化法观察各组大鼠脑内PI3-K和AKT的表达情况。结果与假手术组比较,模型及各药物组神经功能评分均降低(P<0.05);与模型组比较,各用药组24h、72h和7d神经功能恢复明显,神经功能评分上调,以72h和7d点改善尤为明显(P<0.01);失荅剌知丸72h、7d组神经功能评分较金纳多组显著提高(P<0.01)。24h脑细胞凋亡情况显示:失荅剌知丸组在24h组凋亡阳性细胞数明显低于金纳多组和模型组(P<0.01)。与假手术组比较,模型组、各药物组PI3-K和AKT的表达增高(P<0.01);与模型组比较,各药物组PI3-K和AKT的表达增高(P<0.01);与金纳多组比较,失荅剌知丸组PI3-K和AKT的表达增高,其中24h、72h、7d表达明显(P<0.01)。结论失荅剌知丸可明显改善脑缺血/再灌注损伤大鼠的神经功能,抑制神经细胞凋亡;上调PI3-K和AKT的表达,激活PI3-K/AKT信号通路,可能是其发挥神经保护作用的机制之一。

大鼠脑缺血再灌注后海马组织PI3-K信号通路的变化

目的探讨脑缺血再灌注(I/R)损伤后海马组织PI3-K信号通路的变化情况。方法线栓法制备脑I/R大鼠模型,采用Western印迹法检测大鼠海马组织PI3-K的表达。结果与正常对照组比较,脑缺血1h再灌注12、24、72h各组,海马组织PI3-K的表达均明显增加,且在12～72h之间PI3-K表达有逐渐增加的趋势。结论PI3-K信号通路参与了脑I/R引起的海马神经元损伤的病理过程。

柴胡三参胶囊含药血清对骨髓间充质干细胞分化为心肌细胞过程中PI3-K/Akt信号通路干预

目的：研究柴胡三参胶囊含药血清对骨髓间充质干细胞分化为心肌细胞过程中PI3-K/Akt信号通路的影响,探讨其抗心律失常机制与PI3-K/Akt信号转导通路的相关性。方法：将P3代骨髓间充质干细胞随机分为4组,分别为BMP-2组、BMP-2＋含药血清组、含药血清组及空白血清组,以MTT法测BMSCs增殖情况,确定最佳浓度及最佳时间;加入相应浓度的诱导剂及血清,诱导至最佳时间,Western blotting法检测各组细胞内Akt蛋白表达水平;RT-PCR法检测各组细胞内GATA-4、β-MHC m RNA表达情况。结果：与空白血清组相比,BMP-2组、BMP-2＋含药血清组、含药血清组Akt、GATA-4、β-MHC表达水平均明显升高,统计学具有明显差异（P〈0.01）;与BMP-2组相比,BMP-2＋含药血清组表达水平升高（P〈0.05）,与含药血清组相比,BMP-2＋含药血清组表达水平升高（P〈0.05）;BMP-2组与含药血清组比较,差异无统计学意义（P〉0.05）。结论：柴胡三参胶囊能够通过作用于PI3-K/Akt信号通路诱导骨髓间充质干细胞向心肌细胞分化。

PI3-K-AKT信号转导途径与凋亡的关系

PI3-K(phosphatidylinositol3-kinase,磷脂酰肌醇3-激酶)-AKT(v-aktmurinethymomaviraloncogenehomo-log)信号转导途径是细胞内重要的信号转导通路,在细胞的凋亡、存活、增殖以及细胞骨架的变化等活动中发挥重要的生物学功能,其中尤为重要的是它对细胞凋亡、存活的调节作用。细胞凋亡是一个瀑布式的基因表达结果,在其发生与调控过程中有许多基因产物的参与,PI3-K-AKT信号转导途径通过对这些凋亡相关基因的调节作用在凋亡的发生与调控过程中发挥重要的生物学功能。

红景天苷对大鼠脑缺血-再灌注损伤后PI3-K、p-Akt及Caspase-3表达的影响

目的:观察红景天苷对大鼠脑缺血-再灌注损伤后PI3-K、p-Akt及Caspase-3表达的影响。方法:将60只SD雄性大鼠随机分为假手术组12只、脑缺血-再灌注组(模型组)及红景天苷组(10 mg/kg)各24只。采用线栓法制备大鼠右侧大脑中动脉缺血-再灌注模型,观察缺血2 h再灌注6 h、12 h、24 h、48 h 4个不同时间点,采用Western Blotting法检测PI3-K、p-Akt及Caspase-3的蛋白表达。结果:与假手术组比较,模型组及红景天苷组4个不同时间点PI3-K、p-Akt、Caspase-3蛋白表达量均显著升高,差异均有统计学意义(P<0.01)。与模型组比较,红景天苷组4个不同时间点PI3-K、p-Akt蛋白表达量均升高,Caspase-3蛋白表达量均减少,差异均有统计学意义(P<0.05)。模型组及红景天苷组PI3-K、p-AKT蛋白表达趋势均从再灌注6 h开始逐渐升高,24 h达高峰,48 h较24 h下降,但高于12 h;Caspase-3蛋白表达趋势均从再灌注6 h开始逐渐升高,48 h达高峰。结论:红景天苷可能通过激活PI3-K/Akt信号转导通路,上调PI3-K、p-Akt的蛋白表达,抑制Caspase-3的蛋白表达,从而发挥对大鼠脑缺血-再灌注损伤抗凋亡的神经保护作用。

运动对衰老心肌肌力流失征中PI3-K/Akt信号通路的影响

老年人骨骼肌力流失征（Age-related sarcopenia）是一种随年龄增加而出现的以肌肉质量、体积以及肌肉力量下降等为主要特征的老年多发性机能退化病征。按照这种表型，Lin等提出了心肌sarcopenia的概念，并将其定义为：“随年龄增加而出现的心肌细胞减少和心血管功能减退的一种老年病征”。心肌sarcopenia的主要表型为：（1）随年龄的增加，心肌细胞数量下降，剩余的心肌细胞发生肥大，心肌纤维横断面积增加，心肌间质细胞面积增大且纤维化明显。特殊染色发现细胞内脂肪聚集，糖原储量下降；（2）左心室功能伴随心室结构变化而改变，