米诺环素通过调控PI3K/Akt通路抑制硝普钠诱导的PC12细胞凋亡

 目的： 探讨PI3K/Akt信号通路在米诺环素（minocycline,MC）抑制硝普钠(sodium nitoprusside,SNP)诱导的PC12细胞凋亡中的作用。方法：将体外培养的PC12细胞分为4组：空白对照组、SNP组、MC+SNP组和PI3K抑制剂LY294002+ MC+SNP组。用四甲基偶氮唑盐（MTT）法检测细胞活力,流式细胞术检测细胞凋亡;Western blotting检测不同时点（0.5、1、2、3 h）各处理组PI3K/Akt通路蛋白p-Akt和Akt的表达。结果：SNP处理PC12细胞24 h能抑制细胞生长,加入10 μmol/L MC预处理30 min可明显提高细胞活力,降低细胞凋亡率（P<0.05）,抑制SNP诱导的PC12细胞凋亡。MC组的p-Akt表达高于其它组,而加入LY294002后可阻断MC的上述效应。结论：MC可通过调控PI3K/Akt通路抑制SNP诱导的PC12细胞凋亡。     

Apigenin, a dietary flavonoid, sensitizes human T cells for activation-induced cell death by inhibiting PKB/Akt and NF-kappaB activation pathway

Resistance of T cells to activation-induced cell death (AICD) is associated with autoimmunity and lymphoproliferation. We found that apigenin (4',5,7-trihydroxyflavone), a non-mutagenic dietary flavonoid, augmented both extrinsic and intrinsic pathways of apoptosis in recurrently activated, but not in primarily stimulated, human blood CD4+ T cells. Apigenin potentiated AICD by inhibiting NF-kappaB activation and suppressing NF-kappaB-regulated anti-apoptotic molecules, cFLIP, Bcl-x(L), Mcl-1, XIAP and IAP, but not Bcl-2. Apigenin suppressed NF-kappaB translocation to nucleus and inhibited IkappaBalpha phosphorylation and degradation in response to TCR stimulation in reactivated peripheral blood CD4 T cells, as well as in leukemic Jurkat T cell lines. Among the pathways that lead to NF-kappaB activation upon TCR stimulation, apigenin selectively inhibited PI3K-PKB/Akt, but not PKC-theta activation in the human T cells, and synergized with a PI3K inhibitor to markedly augment AICD. Apigenin also suppressed expression of anti-apoptotic cyclooxygenase 2 (COX-2) protein in activated human T cells, but it did not affect activation of Erk MAPKinase. Thus, in chronically activated human T cells, relatively non-toxic apigenin can suppress anti-apoptotic pathways involving NF-kappaB activation, and especially cFLIP and COX-2 expression that are important for functioning and maintenance of immune cells in inflammation, autoimmunity and lymphoproliferation.     

周络通提取物Z-6对高糖所致Schwann细胞损伤和PI3K/Akt/nNOS通路的影响

 目的:探讨磷酯酰肌醇3-激酶/蛋白激酶B/神经元型一氧化氮合酶（PI3K/Akt/nNOS）信号通路在周络通提取物抗糖尿病周围神经病变中的作用。方法:将体外培养的雪旺（Schwann）细胞分为正常组（D-葡萄糖25 mmol/L）、高糖模型组（D-葡萄糖100 mmol/L）、周络通提取物活性部位5（Z-5）+高糖组、周络通提取物活性部位6（Z-6）+高糖组、周络通+高糖组和甲钴胺+高糖组。采用CCK-8试剂盒检测各组细胞的生存活性,相关试剂盒分析培养上清中NO含量和细胞内Ca2+-ATPase活性的变化,流式细胞仪分析细胞的凋亡情况, Western blotting方法检测 Bcl-2、 Bcl-xL、 Bax、 Bak和caspase-3蛋白表达及nNOS和Akt的磷酸化情况。利用PI3K和Akt的显性负性突变体瞬时转染Schwann细胞,探讨PI3K/Akt信号通路在周络通提取物抗糖尿病周围神经病变中的作用。结果:与模型组比较,周络通提取物Z-6能显著提高高糖损伤后Schwann细胞的存活率,提高NO分泌量并明显上调Bcl-2、 Bcl-xL蛋白的表达及Akt、nNOS 的磷酸化水平,同时显著降低细胞凋亡率及Bax、 Bak、 caspase-3蛋白的水平,利用PI3K的显性负性突变体（δp85）阻断nNOS的上游信号通路PI3K/Akt后,NO分泌量减少,但未对Z-6上调nNOS 和Akt磷酸化的作用产生明显影响。结论: 在高糖损伤条件下,周络通提取物Z-6上调nNOS蛋白磷酸化水平,促进抗凋亡因子的表达,抑制促凋亡因子及caspase-3关键蛋白酶的表达,降低Schwann细胞凋亡率,从而提高高糖损伤细胞的存活率,这些作用与PI3K/Akt/nNOS通路的关系有待进一步研究。     

IL-12 inhibits glucocorticoid-induced T cell apoptosis by inducing GMEB1 and activating PI3K/Akt pathway

Interleukin (IL)-12 is an important pro-inflammatory cytokine that has been shown to play a role in T cell survival, at least in part by activating the PI3K/Akt pathway. Glucocorticoid modulatory element binding protein (GMEB)1 and 2 are closely related proteins that modify the glucocorticoid receptor binding locus and thus modulate glucocorticoid-mediated gene induction effects, including apoptosis. GMEB1 associates with caspases and prevents apoptosis of cells in the nervous system. We have observed, in preliminary studies, that IL-12 up-regulates GMEB mRNA in human T cells, and postulated that this may contribute to the anti-apoptotic effect of IL-12 on T cells, in particular with regard to glucocorticoid induced apoptosis. Here, we confirm that IL-12 rescue of dexamethasone induced T cell apoptosis involves the PI3K/Akt pathway and that IL-12 induces GMEB1 and GMEB2. A siRNA knockdown of GMEB1 reverses the protective effect of IL-12 on dexamethasone induced T cell apoptosis. Thus, IL-12 protects T cells from glucocorticoid induced apoptosis via PI3K/Akt pathway and via induction of GMEB1, which is likely to reduce transactivation of the glucocorticoid receptor and induction of apoptotic genes. As glucocorticoid induced apoptosis occurs both in physiological and pathological/therapeutic situations, and IL-12 is actively involved in a variety of inflammatory and immune responses, the ability of IL-12 to inhibit steroid responses and increase T cell survival through GMEB1 has wide ranging implications. Manipulating GMEB may be used therapeutically to enhance the resistance or the sensitivity to steroids.     

Ghrelin对棕榈酸诱导的内皮细胞凋亡的影响及机制

 目的 探讨ghrelin能否抑制棕榈酸诱导的大鼠主动脉内皮细胞凋亡及其与PI3K/Akt通路的关系。 方法 大鼠主动脉内皮细胞在分别在含或不含0.3mM棕榈酸的DMEM培养基中孵育,培养基中加或不加ghrelin及PI3K/Akt的阻断剂LY294002,流式细胞仪Annexin Ⅴ/PI法检测凋亡,分光光度计检测caspase-3活性,Western blot检测总Akt及磷酸化Akt。 结果0.3mM棕榈酸作用24小时增加大鼠主动脉内皮细胞凋亡,Ghrelin抑制棕榈酸诱导的内皮细胞凋亡。棕榈酸干预内皮细胞24小时能显著抑制Akt的磷酸化,加入ghrelin可引起Akt的活化。Ghrelin引起的Akt的活化能够显著地被PI3K/Akt阻断剂LY294002所阻断,而且LY294002能够阻断ghrelin对棕榈酸诱导的内皮细胞凋亡的保护作用。 结论 Ghrelin能够抑制棕榈酸诱导的大鼠主动脉内皮细胞凋亡,ghrelin的抗凋亡作用至少是部分通过PI3K/Akt通路起作用的。     

Aspirin reduces the apoptotic effect of etoposide via Akt activation and up-regulation of p21(cip)

Previous studies on the apoptotic effect of aspirin mainly focus on colorectal cancer and breast carcinoma. Few studies have been designed to explore the effect of aspirin on hepatocellular carcinoma. In the present study, we observed that aspirin caused G0/G1 phase cell cycle arrest and reduced etoposide induced caspase-3 activation in hepatocellular carcinoma G2 (HepG2) cells. Further investigation demonstrated that aspirin notably enhanced the activity of Akt and ERK1/2. Blocking the activation of Akt by the PI3-K-selective inhibitor wortmannin abrogated the anti-apoptotic effect of aspirin while the MEK inhibitor U0126 did not. p21(cip), an important substrate of Akt, is involved in the regulation of cell cycle arrest and apoptosis. Our data showed that the protein expression and ser146 phosphorylation levels of p21(cip) were significantly increased after treatment with aspirin, whereas p53 or p27 showed no change. The increase of p21(cip) protein levels was also scavenged by wortmannin but not by U0126. Moreover, reduction of caspase-3 activity induced by aspirin was attenuated by silencing p21(cip) expression. These results indicated that the anti-apoptotic effect of aspirin was dependent on activation of Akt which inhibited cell apoptosis by up-regulating p21(cip) and blocking caspase-3 activation. These findings could have clinical relevance in anticancer therapy and aspirin co-treatment of human malignancies.     

Effect of IL-5, glucocorticoid, and Fas ligation on Bcl-2 homologue expression and caspase activation in circulating human eosinophils

IL-5 is a potent eosinophil viability-enhancing factor that has been strongly implicated in the pathogenesis of IgE-mediated inflammation in vivo. Recently published data have suggested that IL-5 (and related cytokines) may act by altering the expression of the anti-apoptotic regulator Bcl-2 or its homologues, but this is controversial. The behaviour of the recently described pro-apoptotic cysteine proteases (caspases) in eosinophils after IL-5 treatment has not been explored. We examined the effect of IL-5 on the expression of four major Bcl-2 homologues, as well as on the expression/activation of key members of the caspase cell death cascade in cultured circulating human eosinophils. The effect of relevant inducers of eosinophil apoptosis (glucocorticoid and Fas ligation) on these regulatory proteins was also examined. We observed baseline expression of the anti-apoptotic Mcl-1 and pro-apoptotic Bax proteins in immunoblots of eosinophil lysates, but not Bcl-x, Bcl-2. IL-5 treatment had the effect of maintaining this basal level of expression over time without altering the balance of Bcl-2 homologues. The (upstream) caspase 8 and (downstream) caspase 3 proenzymes were detected in eosinophils at baseline, and were processed during spontaneous and stimulated eosinophil death. IL-5 completely blocked caspase processing in spontaneous and dexamethasone-induced cell death, and significantly slowed processing during Fas ligation. Our data do not support the theory that IL-5 acts by altering the balance of anti-apoptotic and pro-apoptotic Bcl-2 homologues, but suggest that it may act by regulating activation of the caspase cell death cascade.     

Role of stromal cells and their products in protecting young and aged B-lineage precursors from dexamethasone-induced apoptosis

Bone marrow stromal cells are potent providers of stimuli that induce proliferation of B-cell precursors. We proposed that stromal cells play a role in protecting B-lineage cells from corticosteroid-induced apoptosis. We found that stromal cells protected B-cell precursors from dexamethasone-induced apoptosis, but this did not strictly correlate with interleukin-7 (IL-7) production. To determine if stromal-derived factors were involved in protection of B-cell precursors from apoptosis, we examined the activity of three lymphopoietic growth factors: IL-7, stem cell factor (SCF), and insulin-like growth factor-1 (IGF-1). Either IL-7 or IGF-1 alone protected B-cell precursors from dexamethasone-induced apoptosis. The combined activities of IGF-1 and IL-7 were additive rather than synergistic. SCF did not protect B-cell precursors from apoptosis. Aging altered the ability of B-cell precursors to respond to protective stimuli induced by IL-7 and IGF-1. Precursors from aged animals were deficient in ability to modulate expression of apoptosis regulatory genes Bax, Bcl-2, and Bcl-x in comparison to B-cell precursors from young animals. Taken together, these results suggest that stromal cells can protect B-lineage precursors from a corticosteroid-induced apoptotic signal, protection is mediated by stromal-derived cytokines, and aging decreases the ability of B-cell precursors to respond efficiently to protective stimuli.     

Increased Apoptosis of CD20+ IgA+ B Cells is the Basis for IgA Deficiency: The Molecular Mechanism for Correction In Vitro by IL-10 and CD40L

IgA deficiency is the most common primary immunodeficiency in humans. Comparative analysis of gene expression in PBMC from IgA-deficient (IgAd) and normal donors using functional multiplex panels showed overexpression of the Caspase-1 (CASP-1) gene. Cells from all the IgAd donors (n=7) expressed 4–10-fold caspase-1 mRNA over normal controls (n=5). CD19⁺ B cells from all IgAd donors produced IgA in cultures following IL-10 and CD40L with Staphylococcus aureus (Cowan) (SAC) or tetanus toxoid (TT) treatments. In CD19⁺ B cells from IgAd donors, reconstitution of IgA secretion was associated with protection of the CD20⁺ B cell population that underwent apoptosis in the absence of IL-10, CD40L, and TT (triple treatment). Caspase-1 gene expression was decreased in the reconstituted cells. Furthermore, treatment with a caspase-1 inhibitor also independently protected against B cell apoptosis in vitro. An apoptosis-specific cDNA array showed differential expression of 4 out of 96 genes and a shift towards survival-related gene expression from the apoptotic to the protected B cells after triple treatment. There was an increase in the expression of the IAP-2 (inhibitor of apoptosis) gene in the reconstituted cells. Upregulation of the IAP-2 gene protects B cells from deletion and allows for IgA secretion in this system. The inability to detect secreted IgA in IgAd patients could result from the loss of IgA-committed B cells that express high levels of caspase-1.     

羟氯喹通过PI3K/Akt通路对系统性红斑狼疮外周血单个核细胞凋亡的作用研究

目的：探讨羟氯喹对SLE患者外周血单个核细胞的凋亡作用及其相关机制。方法：对30例活动期SLE患者及15例正常健康人抽血分离PBMCs细胞进行培养,分为正常对照组、SLE组、羟氯喹5 mg/L、羟氯喹25 mg/L组,MTT法检测细胞生长抑制,采用Annexin V/PI流式细胞仪细胞检测凋亡率,Western blot方法检测BAX、BCL-2、PI3K、pAKt及mTOR等相关蛋白的表达影响。同时加入羟氯喹HCQ 25 mg/L和PI3K/AKT通路抑制剂LY294002 20 μmol/L,作用SLE患者的PBMCs细胞48 h,检测PBMCs细胞生长抑制和凋亡率。结果：SLE组比正常对照组PBMCs细胞生长抑制率和凋亡率显著升高（P<0.05）;与SLE组相比,羟氯喹5 mg/L和25 mg/L组细胞生长抑制率和凋亡率显著升高（P<0.05）。羟氯喹组与SLE组比较,PI3K、pAKt、mTOR、bcl-2的表达明显下降,差异有统计学意义（P<0.05）,bax和caspase-3的表达增加,差异有统计学意义（P<0.05）。PI3K/AKT抑制剂 LY294002能够阻断羟氯喹导致的SLE患者PBMCs细胞凋亡。结论：羟氯喹能够通过PI3K/Akt信号通路促进SLE患者体外PBMCs的凋亡。     

Stepholidine protects against H2O2 neurotoxicity in rat cortical neurons by activation of Akt

The fundamental pathological process(es) associated with schizophrenia (SZ) remain(s) uncertain, but multiple lines of evidence suggest that this condition is associated with excessive stimulation of striatal dopamine (DA) D2 receptors, deficient stimulation of medial prefrontal cortex (mPFC) D1 receptors as well as neuronal apoptosis. Unlike typical antipsychotics, stepholidine (SPD), which is isolated from the Chinese herb stephania, has D1 and D2 dual properties and regulates neuronal cell differentiation and proliferation. It is unknown, however, whether it possesses a neuroprotective property. Here, we report that SPD prevented neuronal cell death from H2O2 exposure and increased the levels of phosphorylated Akt (pAkt), a serine/threonine protein kinase. The SPD-induced neuroprotection and activation of Akt were blocked by LY294002, a PI3-K inhibitor, suggesting that the anti-apoptotic action of SPD is mediated via the PI3-K/Akt signaling pathway. Thus, as a survival or anti-apoptotic factor for neuronal cells, SPD may contribute to the therapeutic action of SPD in SZ treatment.     

Hypo-active variant of IL-2 and associated decreased T cell activation contribute to impaired apoptosis in autoimmune prone MRL mice

Apoptosis of activated lymphocytes is crucial to the maintenance of immune homeostasis and self-tolerance, as demonstrated by the well-known autoimmune MRL lpr mouse lacking the death receptor Fas. However, even MRL+/+ activated T cells have a resistance to Fas-mediated apoptosis as compared to T cells from the non-autoimmune FVB/N strain. To understand the molecular mechanisms underlying these strain differences, we studied biochemical characteristics of T cells upon activation. Compared to FVB/N T cells, MRL T cells under-expressed procaspase-3 but over-expressed FLIP(L). In addition, up-regulation of Bcl-x(L), IL-2, and CD25 was diminished in MRL cells, suggesting inadequate T cell activation. Upon finding that MRL, like other autoimmune strains NOD and SJL, has a hypo-active variant of the IL-2 gene, we added wild-type murine recombinant (mr)IL-2 during activation. Exogenous mrIL-2 restored MRL apoptosis to the level of FVB/N; in addition, expression of procaspase-3, and FLIP(L), Bcl-x(L) and CD25 was normalized. These results suggest that defective MRL T cell activation, in part due to hypo-active IL-2, underlies the impaired apoptosis of this strain. In addition, the hypo-active variant of IL-2 shared among autoimmune strains may, by causing diminished cell activation and cell death, predispose these strains to develop autoimmune disease.     

芍药苷对APP/PS1小鼠的神经细胞保护作用及机制研究

目的:探讨芍药苷(paeoniflorin,PF)通过抑制细胞凋亡通路而产生神经细胞保护作用的机制。方法:分别选用15只5月龄雄性APP/PS1非显性小鼠作为正常对照组,15只5月龄雄性APP/PS1双转基因小鼠为模型组和15只5月龄雄性APP/PS1双转基因小鼠为给药组(5 mg/kg的PF腹腔注射)。采用水迷宫实验检测各组小鼠的学习和记忆能力。采用TUNEL荧光染色法检测脑内神经细胞凋亡情况。采用Western Blot检测脑内皮层及海马区PI3K、Akt、p-PI3K、p-Akt、caspase-3、caspase-9、Bcl-2和Bax的蛋白表达水平,并用免疫组化分析caspase-3和caspase-9的蛋白表达水平及分布情况。结果:(1)与正常对照组相比,APP/PS1模型组小鼠的学习和记忆能力明显下降;与APP/PS1模型组相比,PF明显改善小鼠的学习和记忆能力。(2)与正常对照组相比,APP/PS1模型组小鼠脑内神经细胞凋亡明显增多,分布区域较广,而PF给药组小鼠凋亡细胞明显减少。(3)与APP/PS1模型组相比,PF给药组能显著下调促凋亡因子caspase-3、caspase-9和Bax的表达水平(P0.05),同时上调抑凋亡因子pPI3K、p-Akt和Bcl-2的表达水平(P0.05)。结论:PF可能通过激活PI3K/Akt通路而上调Bcl-2,下调caspase-9、caspase-3和Bax的蛋白表达水平,从而抑制神经细胞凋亡和保护神经细胞,以治疗神经退行性疾病。     

Precursor IGF-II (proIGF-II) and mature IGF-II (mIGF-II) induce Bcl-2 And Bcl-X L expression through different signaling pathways in breast cancer cells

IGF-II plays a crucial role in fetal and cancer development by signaling through the IGF-I receptor. We have shown that inhibition of IGF-II by resveratrol (RSV) induced apoptosis and that proIGF-II (highly expressed in cancer) was more potent than mIGF-II in inhibiting this effect. Thus, we hypothesized that IGF-II differentially regulates the signaling cascade of the IGF-I receptor to stimulate the anti-apoptotic proteins Bcl-2 and Bcl-X(L) to prevent apoptosis. RSV treatment to breast cancer cells inhibited Bcl-2 and Bcl-X(L) expression and induced mitochondrial membrane depolarization. ProIGF-II was more potent than mIGF-II in: (1) activating the PI3/Akt pathway, (2) regulating Bcl-2 and Bcl-X(L) expression, and (3) inducing phosphorylation/nuclear translocation of Cyclic AMP-responsive element binding protein. Furthermore, IGF-II differentially regulated the intracellular translocation of Bcl-2 and Bcl-X(L), a critical process in breast cancer progression to hormone-independence. Our study provides a novel mechanism of how proIGF-II promotes progression and chemoresistance in breast cancer development.     

Overexpression of Bcl-2 does not rescue impaired B lymphopoiesis in IL- 7 receptor-deficient mice but can enhance survival of mature B cells

IL-7 receptor-deficient (IL-7R(-/-)) mice are lymphopenic as a result of defective cell production at early steps in both B and T lymphopoiesis. In the bone marrow, there is an incomplete block in B cell development at the transition from the pro-B to the pre-B cell stage. As a consequence, peripheral lymphoid organs of IL-7R(-/-) mice contain abnormally low numbers of mature surface (s) Ig-expressing B cells and this is accompanied by a relative increase in immature sIg- B cells. Transgenic expression of the anti-apoptotic protein Bcl-2 in IL- 7R(-/-) mice rescues the defect in T cell development and in mature T cell function. The present report shows that constitutive expression of Bcl-2 is incapable of rescuing B lymphopoiesis in IL-7R(-/-) mice but can enhance survival of those mature B cells which escape the developmental arrest. Thus the essential role of IL-7R signaling in B lymphoid cells cannot be replaced by Bcl-2, indicating that in B lymphopoiesis IL-7R signaling is necessary for promoting cell division and/or for inhibiting a Bcl-2-insensitive pathway to apoptosis.      

三氧化二砷联合顺铂抑制C6胶质瘤细胞增殖的实验研究

目的探讨三氧化二砷(As2O3)联合顺铂(CDDP)抑制C6神经胶质瘤细胞增殖情况及其分子机制。方法体外实验采用MTT法检测对C6神经胶质瘤细胞的抑制率,流式细胞法检测C6胶质瘤细胞的凋亡及周期,Western blot检测caspase-3、PTEN、PI3K、Akt蛋白表达水平;体内实验采用免疫组化法检测caspase-3、IκB-α调控因子的表达,并观察大鼠的生存情况。结果 As2O3、CDDP及联合应用分别作用于C6神经胶质瘤细胞24 h后的细胞增殖最大抑制率分别为34.37%、31.73%和76.40%,其相应药物浓度分别为12.5、10.0、(12.5+10.0)μmol/L;两者联用后对C6胶质瘤细胞作用24 h后的凋亡率分别为从单独用药时的(4.60±1.12)%、(14.59±0.79)%提高到(36.13±1.55)%;采用PI单染检测的细胞周期也进一步证明了联合用药增加了C6细胞的周期抑制作用。Caspase-3、PTEN蛋白在联合组C6胶质瘤细胞中表达显著上调,而PI3K、Akt蛋白在联合组C6胶质瘤细胞中表达下调;免疫组化法检测结果显示,caspase-3调控因子在联合组用药的C6胶质瘤细胞中的表达上调,而IκB-α调控因子表达下调;但体内实验表明,在18 d观察期内各组大鼠的生存期无明显差异(P=0.2531)。结论 As2O3联合CDDP通过上调caspase-3和PTEN,下调PI3K、Akt及IκB-α抑制胶质瘤细胞体内外的生长。     

Expression and function of X chromosome-linked inhibitor of apoptosis protein in Sjögren's syndrome

Apoptotic cell death in acinar and ductal epithelial cells is thought to play an important role in the development of salivary gland dysfunction in patients with Sjogren's syndrome (SS). We examined the expression of anti-apoptotic molecules in salivary glands from patients with SS. The labial salivary glands from six human T-cell leukemia virus (HTLV)-I-seronegative and eleven HTLV-I-seropositive SS patients were analyzed by immunohistochemistry. In vitro experiments were performed with a human salivary gland cell line (HSG cells). Immunohistologic analyses revealed that Bcl-2 and Bcl-x were preferentially expressed in salivary infiltrating mononuclear cells more than acinar and ductal epithelial cells. In contrast, strong X chromosome-linked inhibitor of apoptosis protein (XIAP) expression was evident in both acinar and ductal epithelial cells. The pattern of expression of these anti-apoptotic molecules was similar in both HTLV-I-seropositive and HTLV-I -seronegative SS patients. Western blot analysis confirmed expression of XIAP in cultured HSG cells. The expression of XIAP in HSG cells was increased by IL-1beta, TGF-beta1, or IL-10. However, XIAP expression was down-regulated by TNF-alpha, which induced apoptotic cell death of HSG cells with an increase in caspase-3 activity. These effects of TNF-alpha in HSG cells were antagonized by IL-1beta, TGF-beta1, or IL-10. Our results suggest that XIAP is important in regulating apoptotic cell death of acinar and ductal epithelial cells in patients with SS.     

白花丹醌对人结肠腺癌Caco-2细胞凋亡、自噬及PI3K/Akt/mTOR信号通路的影响

目的:探讨白花丹醌是否诱导人结肠腺癌Caco-2细胞凋亡和自噬及其对磷脂酰肌醇3-激酶(PI3K)/蛋白激酶B(PKB/Akt)/哺乳动物雷帕霉素靶蛋白(mTOR)信号通路的影响.方法:体外培养Caco-2细胞,分别加入2.5、5、7.5、10、12.5和15μmol/L的白花丹醌作用12、24和36 h后,采用MTT...     

Signaling through interleukin-1 type 1 receptor diminishes Haemophilus somnus lipooligosaccharide-mediated apoptosis of endothelial cells

During sepsis, endothelial cells are both a source and target of pro-inflammatory cytokines (e.g. IL-1alpha, IL-1beta, TNFalpha and others), which may be detrimental to vascular homeostasis. Our laboratory has demonstrated that Haemophilus somnus, a gram-negative pathogen of cattle that causes sepsis and vasculitis, and its lipooligosaccharide (LOS) induce caspases-3, -8 and -9 activation, and apoptosis of endothelial cells in vitro. In this study, we provide evidence that H. somnus LOS increases IL-1alpha and IL-1beta mRNA expression, and caspase-1 activation in endothelial cells. Addition of a caspase-1 inhibitor (YVAD), or incubation in a high extracellular potassium buffer (150 mM), reduced caspase-1 activation and significantly enhanced H. somnus LOS-mediated caspase-3 activation. Likewise, blocking the IL-1 type 1 receptor by addition of IL-receptor antagonist (IL-1ra) significantly enhanced LOS-mediated caspase-3 activation. Conversely, addition of exogenous recombinant bovine IL-1beta (100 ng/mL) to endothelial cells diminished LOS-mediated apoptosis. IL-1beta has been reported previously to protect numerous cell types from apoptosis by activating PI3 kinase/p-Akt signaling pathways. Addition of selective PI3 kinase inhibitors (e.g. wortmannin and LY294002) significantly enhanced LOS-mediated caspase-3 activation. Exposure of endothelial cells to IL-1beta or LOS increased pAkt protein as assessed by western blot. Overall, these results suggest that signaling through the IL-1 type 1 receptor diminishes H. somnus LOS-mediated apoptosis.     

Expression of apoptosis-regulatory proteins in lesions of pulmonary Langerhans cell histiocytosis

AIMS: Pulmonary Langerhans cell histiocytosis (PLCH) is characterized by the presence of lesions containing numerous activated Langerhans cells (LCs). An uncontrolled immune response sustained by activated LCs seems to be involved in the pathogenesis of the disease. The aim of this study was to establish whether disruption of LC apoptosis related to the expression of the Bcl-2 family proteins is implicated in the maintenance of PLCH lesions. METHODS: Six patients with PLCH were evaluated by morphological and immunohistochemical techniques to explore the incidence of apoptosis in pathological LCs and to characterize the expression of Bcl-2-related proteins by these cells. RESULTS: Very few LCs present in PLCH lesions exhibited nuclear apoptotic changes or expressed cleaved caspase-3, whereas they all strongly expressed the anti-apoptotic molecule Bcl-x(L). Interestingly, pulmonary LCs present in intervening lung tissue not involved by the pathological process and known to be immature dendritic cells did not express Bcl-2 family proteins. CONCLUSIONS: These findings suggest that activated LCs present within PLCH lesions are poorly susceptible to apoptosis and, thus, are able to sustain the pathological process by causing continuous local stimulation of T cells. Functional studies are needed, however, to demonstrate that they are actually resistant to programmed cell death.