Fenofibrate Pre-treatment Suppressed Inflammation by Activating Phosphoinositide 3 Kinase/Protein Kinase B(PI3K/Akt) Signaling in Renal Ischemia-Reperfusion Injury

The aim of this study was to investigate the possible beneficial effects of Fenofibrate on renal ischemia-reperfusion injury（IRI） in mice and its potential mechanism. IRI was induced by bilateral renal ischemia for 60 min followed by reperfusion for 24 h. Eighteen male C57BL/6 mice were randomly divided into three groups： sham-operated group（sham）, IRI＋saline group（IRI group）, IRI＋Fenofibrate（FEN） group. Normal saline or Fenofibrate（3 mg/kg） was intravenously injected 60 min before renal ischemia in IRI group and FEN group, respectively. Blood samples and renal tissues were collected at the end of reperfusion. The renal function, histopathologic changes, and the expression levels of pro-inflammatory cytokines [interleukin-8（IL-8）, tumor necrosis factor alpha（TNF-α） and IL-6] in serum and renal tissue homogenate were assessed. Moreover, the effects of Fenofibrate on activating phosphoinositide 3 kinase/protein kinase B（PI3K/Akt） signaling and peroxisome proliferator-activated receptor-α（PPAR-α） were also measured in renal IRI. The results showed that plasma levels of blood urea nitrogen and creatinine, histopathologic scores and the expression levels of TNF-α, IL-8 and IL-6 were significantly lower in FEN group than in IRI group. Moreover, Fenofibrate pretreatment could further induce PI3K/Akt signal pathway and PPAR-α activation following renal IRI. These findings indicated PPAR-α activation by Fenofibrate exerts protective effects on renal IRI in mice by suppressing inflammation via PI3K/Akt activation. Thus, Fenofibrate could be a novel therapeutic alternative in renal IRI.

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.

Protective effects of panax notoginseng saponin on dextran sulfate sodium-induced colitis in rats through phosphoinositide-3-kinase protein kinase B signaling pathway inhibition

BACKGROUND Intestinal inflammation is a common digestive tract disease, which is usually treated with hormone medicines. Hormone medicines are effective to some extent, but long-term use of them may bring about many complications.AIM To explore the protective effects of panax notoginseng saponin(PNS) against dextran sulfate sodium(DSS)-induced intestinal inflammatory injury through phosphoinositide-3-kinase protein kinase B(PI3K/AKT) signaling pathway inhibition in rats.METHODS Colitis rat models were generated via DSS induction, and rats were divided into control(no modeling), DSS, DSS + PNS 50 mg/k, and DSS + PNS 100 mg/kg groups. Then, the intestinal injury, oxidative stress parameters, inflammatory indices, tight junction proteins, apoptosis, macrophage polarization, and TLR4/AKT signaling pathway in colon tissues from rats in each of the groups were detected. The PI3 K/AKT signaling pathway in the colon tissue of rats was blocked using the PI3K/AKT signaling pathway inhibitor, LY294002.RESULTS Compared with rats in the control group, rats in the DSS group showed significantly shortened colon lengths, and significantly increased disease activity indices, oxidative stress reactions and inflammatory indices, as well as significantly decreased expression of tight junction-associated proteins. In addition, the DSS group showed significantly increased apoptotic cell numbers,and showed significantly increased M1 macrophages in spleen and colon tissues.They also showed significantly decreased M2 macrophages in colon tissues, as well as activation of the PI3K/AKT signaling pathway(all P < 0.05). Compared with rats in the DSS group, rats in the DSS + PNS group showed significantly lengthened colon lengths, decreased disease activity indices, and significantly alleviated oxidative stress reactions and inflammatory responses. In addition, this group showed significantly increased expression of tight junction-associated proteins, significantly decreased apoptotic cell numbers, and significantly decreased M1 macrophages in spleen and colon tissues. This group further showed significantly increased M2 macrophages in colon tissues, and significantly suppressed activation of the PI3K/AKT signaling pathway, as well as a dose dependency(all P < 0.05). When the PI3K/AKT signaling pathway was inhibited, the apoptosis rate of colon tissue cells in the DSS + LY294002 group was significantly lower than that of the DSS group(P < 0.05).CONCLUSION PNS can protect rats against DSS-induced intestinal inflammatory injury by inhibiting the PI3K/AKT signaling pathway, and therefore may be potentially used in the future as a drug for colitis.

Multiple implications of 3-phosphoinositide-dependent protein kinase 1 in human cancer

3-phosphoinositide-dependent protein kinase-1(PDK1) is a central mediator of cellular signaling between phosphoinositide-3 kinase and various intracellular serine/threonine kinases,including protein kinase B,p70 ribosomal S6 kinase,serum and glucocorticoid-inducible kinase,and protein kinase C.PDK1 activates members of the AGC family of protein kinases by phosphorylating serine/threonine residues in the activation loop.Here,we review the regulatory mechanisms of PDK1 and its roles in cancer.PDK1 is activated by autophosphorylation in the activation loop and other serine residues,as well as by phosphorylation of Tyr-9 and Tyr-373/376.Src appears to recognize PDK1 following tyrosine phosphorylation.The role of heat shock protein 90 in regulating PDK1 stability and PDK1-Src complex formation are also discussed.Furthermore,we summarize the subcellular distribution of PDK1.Finally,an important role for PDK1 in cancer chemotherapy is proposed.In conclusion,a better understanding of its molecular regulatory mechanisms in various signaling pathways will help to explain how PDK1 acts as an oncogenic kinase in various cancers,and will contribute to the development of novel cancer chemotherapies.

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.

Xuebijing improves intestinal microcirculation dysfunction in septic rats by regulating the VEGF-A/PI3K/Akt signaling pathway

BACKGROUND:This study aims to explore whether Xuebijing(XBJ) can improve intestinal microcirculation dysfunction in sepsis and its mechanism.METHODS:A rat model of sepsis was established by cecal ligation and puncture(CLP).A total of 30 male SD rats were divided into four groups:sham group,CLP group,XBJ + axitinib group,and XBJ group.XBJ was intraperitoneally injected 2 h before CLP.Hemodynamic data(blood pressure and heart rate) were recorded.The intestinal microcirculation data of the rats were analyzed via microcirculation imaging.Enzyme-linked immunosorbent assay(ELISA) kits were used to detect the serum levels of interleukin-6(IL-6),C-reactive protein(CRP),and tumor necrosis factor-α(TNF-α) in the rats.Histological analysis and transmission electron microscopy were used to analyze the injury of small intestinal microvascular endothelial cells and small intestinal mucosa in rats.The expression of vascular endothelial growth factor A(VEGF-A),phosphoinositide 3-kinase(PI3K),phosphorylated PI3K(p-PI3K),protein kinase B(Akt),and phosphorylated Akt(p-Akt) in the small intestine was analyzed via Western blotting.RESULTS:XBJ improved intestinal microcirculation dysfunction in septic rats,alleviated the injury of small intestinal microvascular endothelial cells and small intestinal mucosa,and reduced the systemic inflammatory response.Moreover,XBJ upregulated the expression of VEGF-A,p-PI3K/total PI3K,and p-Akt/total Akt in the rat small intestine.CONCLUSION:XBJ may improve intestinal microcirculation dysfunction in septic rats possibly through the VEGF-A/PI3K/Akt signaling pathway.

口腔鳞癌患者血清miRNA-503-5p、PIK3R1表达水平与临床特征及预后的相关性研究

目的探讨口腔鳞癌患者血清微RNA(miRNA)-503-5p、磷脂酰肌醇-3激酶调节亚基1(PIK3R1)表达水平及其与临床特征和预后的相关性。方法选取2022年3月至2023年11月在康复大学青岛中心医院(青岛市中心医院)就诊的157例口腔鳞癌患者作为疾病组进行前瞻性研究,并根据患者预后情况将口腔鳞癌患者分为预后良好组(n=121)和预后不良组(n=36)。另选取在本院进行体检的136名健康者作为健康组。采用实时聚合酶链反应(qRT-PCR)的方法对各组血清miRNA-503-5p、PIK3R1表达水平进行检测,并比较血清miRNA-503-5p、PIK3R1表达水平与临床特征的关系;采用Pearson相关性分析对患者血清miRNA-503-5p与PIK3R1表达水平的相关性进行分析;采用受试者操作特征(ROC)曲线评估血清miRNA-503-5p、PIK3R1表达水平及二者联合对口腔鳞癌患者预后的预测价值。结果疾病组血清miRNA-503-5p表达水平为1.32±0.19,高于健康组(1.02±0.16),疾病组血清PIK3R1表达水平为0.71±0.13,低于健康组(1.01±0.15),差异均有统计学意义(P<0.05)。Target Scan Human网址预测miRNA-503-5p与PIK3R1间存在结合位点,Pearson相关性分析结果显示,口腔鳞癌患者血清miRNA-503-5p与PIK3R1表达水平呈负相关(r=-0.453,P<0.001)。TNM分期、分化程度、淋巴结转移情况等临床特征不同的患者血清miRNA-503-5p、PIK3R1表达水平比较,差异均有统计学意义(P<0.05)。预后不良组血清miRNA-503-5p表达水平为1.52±0.21,高于预后良好组(1.26±0.18),预后不良组血清PIK3R1表达水平为0.59±0.10,低于预后良好组(0.75±0.14),差异均有统计学意义(P<0.05)。血清miRNA-503-5p、PIK3R1联合预测口腔鳞癌患者预后情况的曲线下面积(AUC)为0.903,灵敏度和特异度分别为76.86%和94.44%,二者联合预测优于血清miRNA-503-5p、PIK3R1单独预测(P<0.05)。结论在口腔鳞癌患者中血清miRNA-503-5p呈高表达,PIK3R1呈低表达,二者表达与TNM分期、分化程度、淋巴结转移情况等临床特征以及预后有关,可以作为评估口腔鳞癌患者预后的生物学指标。

PI3K/AKT信号通路对冷却滩羊肉贮藏期间细胞凋亡的影响

以滩羊后腿肉为研究对象,采用10μmol/L磷脂酰肌醇3激酶(phosphoinositide 3-kinase,PI3K)抑制剂LY294002溶液对滩羊肉进行注射处理,4℃条件下分别贮藏0、2、4、6、8 d,通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳和蛋白质免疫印迹分析PI3K、蛋白激酶B(protein kinase B,AKT)蛋白的表达情况,以此验证PI3K/AKT信号通路抑制的有效性,同时分析滩羊肉贮藏期间能量因子、氧化应激水平、线粒体损伤程度以及胱天蛋白酶(cysteine aspastic acid-specific protease,Caspase)-3活性的变化,以探索PI3K/AKT信号通路对冷却滩羊肉贮藏期间细胞凋亡途径的诱导机制。结果表明,PI3K和AKT蛋白表达量均减少,验证了PI3K/AKT信号通路被抑制的有效性。与对照组相比,LY294002处理组线粒体ATP、糖原含量、琥珀酸脱氢酶和柠檬酸合成酶活性显著下降(P<0.05);线粒体活性氧(reactive oxygen species,ROS)逐渐增多,氧化应激水平和线粒体膜通透性转换孔(mitochondrial permeability transition pore,MPTP)开放程度增加;膜电位显著下降(P<0.05);凋亡因子Caspase-3活性显著升高(P<0.05),表明PI3K/AKT信号通路通过促进ROS产生并与PI3K相互作用,介导了下游Caspase-3的活化,使线粒体结构与功能受损,导致MPTP开放、膜电位降低,进而诱发细胞凋亡。

基于PI3K/Akt/mTOR 通路探究七氟醚麻醉对大鼠神经细胞凋亡的影响

目的探讨七氟醚麻醉对大鼠认知功能及神经细胞凋亡的影响。方法取96只大鼠,随机分为对照组(吸入2 L·min^(−1)氧气)、七氟醚低浓度组(吸入体积分数为1%的七氟醚+2 L·min^(−1)氧气)、七氟醚中浓度组(吸入体积分数为2%的七氟醚+2 L·min^(−1)氧气)、七氟醚高浓度组(吸入体积分数为4%的七氟醚+2 L·min^(−1)氧气),持续吸入6 h。用Morris水迷宫实验观察各组大鼠认知能力,用HE染色观察海马组织学形态,用酶联免疫吸附试验(enzyme linked immunosorbent assay,ELISA)测定海马组织中枢神经特异性蛋白(soluble protein 100β,S-100β)、神经元特异性烯醇化酶(neuron-specific enolase,NSE)、白细胞介素-1β(interleukin-1β,IL-1β)和肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)水平,流式细胞术测定神经细胞凋亡情况,蛋白印迹法(Western blotting)测定海马组织B淋巴细胞瘤-2(B-cell lymphoma-2,Bcl-2)、Bcl-2相关X蛋白(Bcl2-associated X protein,Bax)、磷酸化磷脂酰肌醇3-激酶(phosphorylated phosphatidylinositol 3-kinase,p-PI3K)、磷酸化丝氨酸/苏氨酸激酶(phosphorylated serine/threonine kinase,p-Akt)和磷酸化哺乳动物雷帕霉素靶蛋白(phosphorylated mammalian target of rapamycin,p-mTOR)的水平。结果HE染色结果表明,对照组海马组织神经细胞结构正常,排列紧密,七氟醚各浓度组大鼠海马组织神经细胞减少,排列紊乱,分布不均匀。与对照组比较,七氟醚各浓度组大鼠逃避潜伏期时间,S100-β、NSE、IL-1β、TNF-α水平,Bax蛋白水平和神经细胞凋亡率均升高,穿越平台次数,平台停留时间,Bcl-2、p-PI3K、p-Akt和p-mTOR蛋白水平均降低(P<0.05);七氟醚各浓度组诸项指数水平变化规律相同,并呈剂量依赖性(P<0.05)。结论七氟醚麻醉可诱导大鼠神经细胞凋亡,使大鼠认知能力衰退,其可能与调控PI3K/Akt/mTOR信号通路有关。

紫草素对人胃癌MGC803细胞增殖、迁移、侵袭和凋亡的影响

目的探讨紫草素对人胃癌MGC803细胞增殖、迁移、侵袭和凋亡的影响及机制。方法将对数生长期MGC803细胞随机分为空白对照组、紫草素组、紫草素+胰岛素样生长因子-1(IGF-1)组和紫草素+LY294002组。空白对照组细胞在无药培养基中培养,紫草素组细胞在含终浓度10μmol·L^(-1)紫草素的培养基中培养,紫草素+IGF-1组细胞在含终浓度10μmol·L^(-1)紫草素和终浓度10μmol·L^(-1) IGF-1的培养基中培养,紫草素+LY294002组细胞在含终浓度10μmol·L^(-1)紫草素和终浓度30μmol·L^(-1) LY294002的培养基中培养。培养24 h后,采用细胞计数试剂盒-8法检测细胞增殖情况,流式细胞术检测细胞凋亡情况,划痕实验检测细胞迁移能力,Transwell法检测细胞侵袭能力,Western blot法检测细胞中B细胞淋巴瘤-2(Bcl-2)、Bcl-2相关X蛋白(Bax)、细胞色素C(Cyt C)、激活型caspase-3(cleaved caspase-3)、cleaved caspase-9、磷脂酰肌醇3激酶(PI3K)、磷酸化PI3K(p-PI3K)、蛋白激酶B(PKB)、磷酸化PKB(p-PKB)蛋白表达。结果紫草素组MGC803细胞增殖抑制率和凋亡率显著高于空白对照组(P<0.05);紫草素+IGF-1组MGC803细胞增殖抑制率和凋亡率显著低于紫草素组(P<0.05);紫草素+LY294002组MGC803细胞增殖抑制率和凋亡率均显著高于紫草素组(P<0.05)。紫草素组MGC803细胞划痕愈合率和侵袭细胞数显著低于空白对照组(P<0.05);紫草素+IGF-1组MGC803细胞划痕愈合率和侵袭细胞数显著高于紫草素组(P<0.05);紫草素+LY294002组MGC803细胞划痕愈合率和侵袭细胞数显著低于紫草素组(P<0.05)。紫草素组MGC803细胞中Bcl-2蛋白相对表达量显著低于空白对照组(P<0.05),Bax、Cyt C、cleaved caspase-3、cleaved caspase-9蛋白相对表达量及Bax/Bcl-2比值显著高于空白对照组(P<0.05);紫草素+IGF-1组MGC803细胞中Bcl-2蛋白相对表达量显著高于紫草素组(P<0.05),Bax、Cyt C、cleaved caspase-3、cleaved caspase-9蛋白相对表达量及Bax/Bcl-2比值显著低于紫草素组(P<0.05);紫草素+LY294002组MGC803细胞中Bcl-2蛋白相对表达量显著低于紫草素组(P<0.05),Bax、Cyt C、cleaved caspase-3、cleaved caspase-9蛋白相对表达量及Bax/Bcl-2比值显著高于紫草素组(P<0.05)。紫草素组MGC803细胞中p-PI3K、p-PKB蛋白相对表达量及p-PI3K/PI3K、p-PKB/PKB比值显著低于空白对照组(P<0.05),紫草素组和空白对照组MGC803细胞中PI3K、PKB蛋白相对表达量比较差异无统计学意义(P>0.05);紫草素+IGF-1组MGC803细胞中p-PI3K、p-PKB蛋白相对表达量及p-PI3K/PI3K、p-PKB/PKB比值显著高于紫草素组(P<0.05),紫草素+IGF-1组与紫草素组MGC803细胞中PI3K、PKB蛋白相对表达量比较差异无统计学意义(P>0.05);紫草素+LY294002组MGC803细胞中p-PI3K、p-PKB蛋白相对表达量及p-PI3K/PI3K、p-PKB/PKB比值显著低于紫草素组(P<0.05),紫草素+LY294002组与紫草素组MGC803细胞中PI3K、PKB蛋白相对表达量比较差异无统计学意义(P>0.05)。结论紫草素可抑制人胃癌MGC803细胞增殖、迁移、侵袭并促进其凋亡,其作用机制可能与抑制PI3K/PKB信号通路有关。

益气续骨方调节PI3K/Akt信号通路对激素性股骨头坏死大鼠骨代谢的影响

目的探究益气续骨方调节磷脂酰肌醇3-激酶(PI3K)/蛋白激酶B(Akt)信号通路对激素性股骨头坏死大鼠骨代谢的影响。方法将50只SD雄性大鼠随机分为正常组、模型组、益气续骨方低剂量组、益气续骨方高剂量组、益气续骨方+LY294002组,每组10只。除正常组外,其余组大鼠右臀肌肉注射醋酸泼尼松龙注射液4周建立激素性股骨头坏死模型。造模结束后,益气续骨方低、高剂量组大鼠分别给予益气续骨方0.5 mL(含生药0.285 g/mL)和1 mL(含生药0.57 g/mL)灌胃,益气续骨方+LY294002组大鼠给予益气续骨方1 mL灌胃并腹腔注射6 mg/kg的LY294002,正常组和模型组给予等体积生理盐水灌胃,均1次/d,连续干预8周。ELISA检测大鼠血清白细胞介素-4(IL-4)、白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、血钙、血磷、骨保护素(OPG)、骨钙素(OCN)、碱性磷酸酶(ALP)水平,Micro-CT检测观察股骨头形态,HE染色观察股骨头组织病理形态,TRAP染色观察破骨细胞生成情况,Western blot法检测股骨头组织中骨特异性转录因子2(Runx2)、骨形态发生蛋白2(BMP-2)、裂解半胱天冬酶-3(Cleaved-Caspase-3)、PI3K、Akt蛋白表达情况。结果与正常组比较,模型组大鼠血清IL-4、IL-6、TNF-α、OPG、ALP水平和骨小梁分离度(Tb.Sp)、空骨陷窝率及股骨头组织中Cleaved-Caspase-3蛋白相对表达量均明显升高(P均<0.05),血钙、血磷、OCN水平和骨体积分数(BV/TV)、骨小梁数目(Tb.N)、骨小梁厚度(Tb.Th)及股骨头组织中Runx2、BMP-2、p-PI3K/PI3K、p-Akt/Akt蛋白相对表达量均明显降低(P均<0.05),破骨细胞数量增多,股骨头破坏、骨小梁空间结构紊乱;与模型组比较,益气续骨方低、高剂量组大鼠血清IL-4、IL-6、TNF-α、OPG、ALP水平和Tb.Sp、空骨陷窝率及股骨头组织中Cleaved-Caspase-3蛋白相对表达量均明显降低(P均<0.05),血钙、血磷、OCN水平和BV/TV、Tb.N、Tb.Th及股骨头组织中Runx2、BMP-2、p-PI3K/PI3K、p-Akt/Akt蛋白相对表达量均明显升高(P均<0.05),破骨细胞数量减少,股骨头破坏程度减轻,骨小梁空间结构形态改善;LY294002可减弱益气续骨方对上述指标的改善作用,各指标与益气续骨方高剂量组比较差异均有统计学意义(P均<0.05)。结论益气续骨方可改善激素性股骨头坏死大鼠骨代谢,降低炎症因子水平,减少破骨细胞数量,减轻大鼠股骨头坏死,机制可能与激活PI3K/Akt信号通路有关。

病毒性心肌炎血清外泌体来源的miR-320通过靶向Pik3r1抑制AKT/mTOR通路促进小鼠心肌细胞凋亡

目的探讨病毒性心肌炎血清外泌体miR-320对心肌细胞凋亡的影响及机制。方法使用柯萨奇病毒B3(CVB3)腹腔注射,建立病毒性心肌炎小鼠模型;采用血清外泌体抽提试剂盒提取血清外泌体,与心肌细胞共培养,激光共聚焦显微镜观察心肌细胞摄取外泌体情况;使用miR-320抑制剂或模拟物转染心肌细胞,实时荧光定量PCR检测miR-320表达水平;采用流式细胞术检测心肌细胞凋亡率,Western blot法检测B细胞淋巴瘤因子2(Bcl2)和Bcl2相关X蛋白(BAX)表达水平;生物信息学预测miR-320靶基因并进行基因本体论(GO)和京都基因和基因组百科全书(KEGG)富集分析;荧光素酶报告基因检测miR-320与其靶基因磷脂酰肌醇3激酶调节亚基1(Pik3r1)的作用关系;Western blot法检测miR-320对蛋白激酶B/哺乳动物雷帕霉素靶蛋白(AKT/mTOR)通路蛋白的影响。结果病毒性心肌炎血清外泌体促进心肌细胞凋亡并上调BAX水平,同时降低Bcl2水平;病毒性心肌炎小鼠心肌组织中miR-320显著上调,且miR-320成熟体和miR-320前体pri-miR-320表达在心肌细胞均明显上调;病毒性心肌炎血清外泌体处理的心肌细胞中miR-320水平显著上调,而转染miR-320抑制剂逆转了外泌体引起的miR-320上调及凋亡率升高;Pik3r1是miR-320的靶基因,其过表达逆转miR-320上调导致的心肌细胞凋亡;miR-320过表达抑制AKT/mTOR通路激活。结论病毒性心肌炎血清外泌体miR-320通过靶向Pik3r1抑制AKT/mTOR通路促进小鼠心肌细胞凋亡。

基于PI3K/AKT/mTOR信号通路探讨化瘀通络灸促血管性痴呆大鼠髓鞘再生的作用机制

目的观察化瘀通络灸对血管性痴呆(vascular dementia,VD)大鼠胼胝体磷脂酰肌醇3激酶(phosphatidylinositol 3 kinase,PI3K)/蛋白激酶B(protein kinase B,AKT)/哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin,mTOR)信号通路的影响,探讨化瘀通络灸促VD大鼠髓鞘再生的作用机制。方法经Morris水迷宫筛选后,随机选取12只大鼠纳入假手术组,剩余大鼠复制VD模型成功后,随机分为模型组、艾灸组、艾灸+LY294002组,每组12只。艾灸组予以化瘀通络灸干预,艾灸+LY294002组在化瘀通络灸干预的基础上予以PI3K抑制剂LY294002腹腔注射,采用Longa评分法评价各组大鼠神经功能损伤程度,Morris水迷宫实验检测各组大鼠学习记忆能力,Western blot法检测各组大鼠PI3K/AKT/mTOR信号通路相关蛋白的表达水平,神经髓鞘固蓝染色法观察各组大鼠胼胝体髓鞘的形态,透射电子显微镜观察各组大鼠髓鞘超微结构。结果与假手术组比较,模型组和艾灸+LY294002组大鼠的Longa评分显著升高(P<0.05),逃避潜伏期显著延长(P<0.05),PI3K/AKT/mTOR通路相关蛋白表达水平显著降低(P<0.05),胼胝体内髓鞘纹理不清,排列混乱,边缘呈空泡或空网状改变,髓鞘线圈样结构离散,部分膨出和崩解,有髓神经轴突数量显著减少(P<0.05);与模型组和艾灸+LY294002组比较,艾灸组大鼠Longa评分显著下降(P<0.05),逃避潜伏期显著缩短(P<0.05),PI3K/AKT/mTOR通路相关蛋白表达水平显著提高(P<0.05),胼胝体内髓鞘结构有所恢复,排列整齐,边缘结构较为致密,有髓神经轴突数量显著增加(P<0.05)。结论化瘀通络灸可能通过激活PI3K/AKT/mTOR通路,修复VD大鼠损伤髓鞘并促进其重塑,恢复脑白质功能。

PI3K/Akt信号通路调控急性髓系白血病机制及中医药治疗研究进展

急性髓系白血病(AML)是一种极具侵袭力的血液恶性肿瘤,其特征表现为未成熟的髓系白血病细胞快速增殖。随着基因测序、蛋白组学等现代科学技术的快速发展,AML的发病及预后分子机制的研究逐渐深入,但仍未打破目前AML治疗复发率高、免疫逃逸、微小残留、放化疗副反应大、患者家庭经济及心理负担重的局面。磷脂酰肌醇3激酶/蛋白激酶B(PI3K/Akt)/哺乳动物雷帕霉素靶点是致癌通路中最为经典的一条,不少研究通过该条通路研发出药物以应对AML。近些年,中医药因其具有多层次、多靶点、低不良反应等优势,在肿瘤治疗领域大展身手,发挥重要作用,受到医学界广泛关注与认可。因此,该综述概述了PI3K/Akt信号通路与AML的关系,归纳并发现中药单体和中药复方能介导PI3K/Akt信号通路,抑制肿瘤细胞增殖、迁移、侵袭及血管新生,进而影响AML的病理发展。

胰岛素样生长因子1对人RPE细胞分泌TGF-β2、MMP-2的影响及机制研究

目的研究胰岛素样生长因子1(IGF-1)对人视网膜色素上皮细胞(ARPE-19)表达转化生长因子β2(TGF-β2)、基质金属蛋白酶2(MMP-2)的影响,并探索其作用机制。方法ARPE-19细胞分别按不同浓度IGF-1和不同浓度LY294002培养6 h、12 h、24 h、48 h,采用CCK-8法检测细胞活力,确定IGF-1、LY294002的最佳作用浓度与时间。细胞划痕法检测细胞迁移活性。ELISA法检测细胞培养上清液中TGF-β2浓度。将ARPE-19细胞分为对照组、IGF-1组(80μg·L^(-1) IGF-1)、IGF-1+LY294002组(80μg·L^(-1) IGF-1+30 mmol·L^(-1) LY294002)、LY294002组(30 mmol·L^(-1) LY294002),使用无血清DMEM/F12培养基培养,对照组不做任何处理,分别采用RT-PCR、Western blot检测细胞中TGF-β2、MMP-2、磷脂酰肌醇-3-激酶(PI3K)、蛋白激酶B(AKT)的mRNA和蛋白表达量。结果与0μg·L^(-1) IGF-1比较,80μg·L^(-1) IGF-1的细胞活力24 h变化显著(P<0.05),故确定其为IGF-1最佳作用浓度和时间。与0 mmol·L^(-1) LY294002比较,24 h的30 mmol·L^(-1) LY294002接近半数抑制浓度,故确定其为LY294002最佳作用时间和浓度。细胞划痕法检测结果显示,0μg·L^(-1) IGF-1组、40μg·L^(-1) IGF-1组、80μg·L^(-1) IGF-1组细胞迁移率整体比较及两两比较差异均有统计学意义(均为P<0.05)。ELISA检测结果显示,0μg·L^(-1) IGF-1组、40μg·L^(-1) IGF-1组、80μg·L^(-1) IGF-1组细胞上清液中TGF-β2浓度整体比较及两两比较差异均有统计学意义(均为P<0.05)。RT-PCR、Western blot检测结果显示,IGF-1、LY294002培养24 h,与对照组比较,IGF-1组细胞中TGF-β2、MMP-2、PI3K、AKT的mRNA与蛋白表达水平均升高,而LY294002组细胞中TGF-β2、MMP-2、PI3K、AKT的mRNA与蛋白表达水平均下降(均为P<0.05);与IGF-1组比较,IGF-1+LY294002组细胞中TGF-β2、MMP-2、PI3K、AKT的mRNA与蛋白表达水平均下降(均为P<0.05)。结论IGF-1能促进ARPE-19细胞增殖、迁移;IGF-1可能通过PI3K/AKT信号通路上调ARPE-19细胞中TGF-β2、MMP-2的表达,参与近视的发生与发展。

PI3Kδ过度活化综合征7例报道

目的总结7例PI3Kδ过度活化综合征(activated phosphoinositide 3-kinase delta synd rome,APDS)患儿的临床资料,提高对该病的认识。方法回顾性分析2019年1月—2023年8月湖南省人民医院收治的7例APDS患儿的临床资料。结果7例患儿(男4例,女3例)中位发病年龄为30个月,中位诊断年龄为101个月。临床表现:反复呼吸道感染、肝脾大及多部位淋巴结肿大7例,脓毒血症5例,中耳炎及多发性龋齿3例,腹泻及关节痛2例,淋巴瘤、系统性红斑狼疮各1例。4例患儿行纤维支气管镜检查,管腔内均可见大量散在的结节样突起。最常见的呼吸道病原为肺炎链球菌(4例)。6例患儿为p.E1021K位点错义突变,1例为p.434-475del位点剪切突变。结论p.E1021K是APDS患儿最常见的突变位点。对于具有反复呼吸道感染、肝脾大、多部位淋巴结肿大、中耳炎、龋齿等表现1项或多项,且纤维支气管镜下见散在结节样突起的患儿,需警惕APDS。

大黄素干预PI3K/Akt/mTOR信号通路影响肝癌前病变大鼠铁死亡的作用机制

目的 探究大黄素对二乙基亚硝胺(diethylnitrosamine, DEN)诱导的肝癌前病变大鼠磷脂酰肌醇3-激酶(phosphoinositide 3-kinase, PI3K)/蛋白激酶B(protein kinase B, Akt)/哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin, mTOR)信号转导通路的调控作用及对铁死亡的影响。方法 采用DEN诱发大鼠肝癌前病变进行肝癌前病变造模。随机将50只雄性SD大鼠分为对照组[未造模+10ml/(kg·d)生理盐水灌胃)]、DEN模型组[肝癌前病变造模+10 ml/(kg·d)生理盐水灌胃]、DEN+大黄素组[肝癌前病变造模+80 mg/(kg·d)大黄素浓缩液灌胃]、DEN+护肝片组[肝癌前病变造模+900 mg/kg护肝片灌服]和DEN+大黄素+护肝片组[肝癌前病变造模+80 mg/(kg·d)大黄素浓缩液灌胃+900 mg/kg护肝片灌服],每组各10只大鼠。各组大鼠连续干预治疗12周。生化分析法检测各组大鼠血清丙氨酸氨基转移酶(alanine aminotransferase, ALT)、天门冬氨酸氨基转移酶(aspartate aminotransferase, AST)、白蛋白(albumin, ALB)水平;比较各组大鼠的肝脏指数。酶联免疫吸附试验(enzyme-linked immunosorbent assay, ELISA)法检测各组大鼠血清白细胞介素1β(interleukin 1 beta, IL-1β)、肿瘤坏死因子α(tumor necrosis factor alpha, TNF-α)、IL-10含量。苏木精-伊红(hematoxylin-eosin, HE)染色法观察各组大鼠肝组织病理形态学改变;脱氧核糖核苷酸末端转移酶介导的缺口末端标记法(terminal deoxynucleotidyl transferase mediated dUTP nick-end labeling, TUNEL)分析各组大鼠肝组织细胞凋亡情况。免疫组织化学法检测各组大鼠肝组织中铁死亡中心调节因子谷胱甘肽过氧化物酶4(glutathione peroxidase 4,GPX4)蛋白表达。马松三色染色(Masson′s trichrome staining, MASSON)法分析各组大鼠肝组织病理改变。逆转录聚合酶链反应(reverse transcription polymerase chain reaction, RT-PCR)法检测各组大鼠肝组织中PIK3、Akt、mTOR的mRNA水平。结果 与对照组比较,DEN模型组大鼠ALT水平、AST水平、肝脏指数显著升高,ALB水平显著降低(P均<0.05),血清IL-1β、TNF-α、IL-10含量明显升高(P均<0.05);肝细胞明显炎性浸润,细胞免疫应答增加,肝细胞形态畸变并出现变性死亡;肝组织中GPX4蛋白表达量明显下降(P<0.05),PI3K、Akt、mTOR的mRNA表达量明显上升(P均<0.05)。与DEN模型组比较,DEN+大黄素组、DEN+护肝片组、DEN+大黄素+护肝片组大鼠ALT水平、AST水平、肝脏指数显著降低,ALB显著升高(P均<0.05),血清IL-1β、TNF-α、IL-10含量明显降低(P均<0.05);肝细胞排列趋向正常,炎性浸润减轻,肝细胞弥漫性纤维化病变减弱,血管及胆管周围肝细胞形态逐渐好转,蓝色胶原纤维组织减少;肝组织中GPX4蛋白表达量明显上升(P均<0.05),PI3K、Akt、mTOR的mRNA表达量明显下降(P均<0.05),且上述变化DEN+大黄素+护肝片组改善效果明显优于DEN+大黄素组和DEN+护肝片组(P均<0.05)。结论 大黄素可通过促进组织中铁死亡相关蛋白GPX4表达来改善大鼠肝癌前病变,其作用机制可能与大黄素调控PI3K/Akt/mTOR信号通路有关。