15-deoxy-delta(12,14)-PGJ(2) induces synoviocyte apoptosis and suppresses adjuvant-induced arthritis in rats

Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear hormone receptor superfamily and have a dominant regulatory role in adipocyte and monocyte differentiation. PPAR-gamma agonists are also negative regulators of macrophage activation and have modulatory effects on tumorigenesis. In this study we demonstrate that synovial tissue localized expression of PPAR-gamma in patients with rheumatoid arthritis (RA). We detected markedly enhanced expression of PPAR-gamma in macrophages, as well as modestly enhanced expression in the synovial lining layer, fibroblasts, and endothelial cells. Activation of the PPAR-gamma by 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)) and the synthetic PPAR-gamma ligand (troglitazone) induced RA synoviocyte apoptosis in vitro. Moreover, intraperitoneal administration of these PPAR-gamma ligands ameliorated adjuvant-induced arthritis with suppression of pannus formation and mononuclear cell infiltration in female Lewis rats. Anti-inflammatory effects of 15d-PGJ(2) were more potent than troglitazone. These findings suggest that PPAR-gamma may be an important immunoinflammatory mediator and its ligands, especially 15d-PGJ(2), may be useful in the treatment of RA.     

PPARs and heart diseases

After it has been reported that activation of PPARalpha or PPARgamma suppresses production of proinflammatory cytokines, medical interest in PPARs have grown and a huge research effort has been concentrated. Synthetic antidiabetic thiazolidinediones (TZDs) and natural prostaglandin D2 (PGD2) metabolite, 15d-PGJ2, are well known as ligands for PPARgamma. Hyperlipidemic drugs (fibrates) are synthetic PPARalpha ligands. Recent studies suggest that ligands of PPAR not only regulate glucose and lipid metabolism but also have pleiotropic effects on many tissues and cell types. Ligands of PPARs may become therapeutic agents useful in the prevention of cardiovascular diseases beyond their effects on glucose and lipid metabolism. This review will focus on the latest developments in the PPARs field and the roles of PPAR-dependent pathway in cardiovascular diseases.     

Growth inhibition of esophageal squamous carcinoma cells by peroxisome proliferator-activated receptor-gamma ligands

The growth of human cancer cells expressing peroxisome proliferator-activated receptor-gamma (PPAR-gamma) has been reported to be inhibited by PPAR-gamma ligands. In esophageal squamous-cell carcinoma cell lines T.T, T.Tn, and EC-GI-10, we detected expression of PPAR-gamma and investigated the effects of PPAR-gamma ligands on these cell lines in vitro with the use of troglitazone, pioglitazone, and 15d-PGJ2. Marked growth inhibition by the PPAR-gamma ligands was observed in all cases. The growth-inhibitory effect was evidenced by a dose-dependent inhibition of deoxyribonucleic acid synthesis and was associated with altered cell-cycle progression manifesting G1 arrest. Cell-cycle arrest in T.Tn cells induced by troglitazone could be correlated with an increased level of cyclin-dependent kinase inhibitor p27(Kip1), p21(Cip1/Waf1), and p18(Ink4c). Moreover, troglitazone treatment increased the expression of interleukin-1 alpha, a multifunctional cytokine implicated in antitumor immunity. These findings suggest that troglitazone and other PPAR-gamma ligands have adjuvant or neoadjuvant therapeutic potentials in esophageal cancer.     

六亚甲基二乙酰胺对急性白血病细胞株HL-60和U937分化、凋亡的影响及其机制

目的　研究六亚甲基二乙酰胺 (HMBA)体外诱导HL 6 0和U937细胞分化、凋亡的作用及其机制。方法　流式细胞仪检测细胞分化抗原CD1 1b、CD1 4,细胞凋亡标记Annexin Ⅴ以及进行细胞周期分布和细胞内cyclinD、cyclinE、p2 7抗原的分析 ,RT PCR检测c myc、Rb、Bcl 2基因mRNA的表达。结果　HL 6 0、U937细胞经HMBA处理 72h后CD1 1b表达显著增高 ,高剂量HMBA促使Annexin Ⅴ表达增加。HMBA阻滞HL 6 0、U937细胞于G0 G1 期 ,并使该两种细胞内cyclinE表达显著下降 ,cyclinD、p2 7表达显著增高 ,呈剂量依赖关系 ;HMBA可使HL 6 0、U937细胞c myc、Bcl 2mRNA表达下调 ,而RbmRNA在HL 6 0细胞表达上调 ,在U937细胞则无显著改变。结论　HMBA能诱导HL 6 0、U937细胞出现明显的分化 ,高剂量的HMBA有促使HL 6 0、U937细胞凋亡的倾向 ,其机制可能是通过影响细胞周期调控分子以及有关的增殖分化相关基因的表达 ,从而抑制细胞增殖 ,促进细胞分化。     

过氧化物酶体增殖物激活受体γ激动剂对二氧化硅致成纤维细胞纤维连接蛋白表达的影响

背景:过氧化物酶体增殖物激活受体γ激动剂对转化生长因子β1致矽肺肺间质纤维化作用的影响及机制尚不明确,罕见报道.目的:观察过氧化物酶体增殖物激活受体γ激动剂对转化生长因子β1致矽肺肺纤维化作用的影响.方法:200 mg/L SiO2刺激SD大鼠肺泡巨噬细胞培养上清液作用于中国仓鼠肺成纤维细胞株(CHL)建立矽肺纤维化的体外细胞模型.RT-PCR检测过氧化物酶体增殖物激活受体γ配体15d-PGJ2及其激动剂曲格列酮和齐格列酮对转化生长因子β1诱导CHL的纤维连接蛋白mRNA表达的影响.利用Western印迹技术观察过氧化物酶体增殖物激活受体γ激动剂对转化生长因子β1诱导CHL的纤维连接蛋白表达的影响.结果与结论:①转化生长因子β1 mRNA表达呈一定范围内的剂量(0～5 μg/L)和时间(0～24 h)依赖效应.②过氧化物酶体增殖物激活受体γ配体及激动剂降低了纤维连接蛋白mRNA和蛋白的表达.结果提示过氧化物酶体增殖物激活受体γ激动剂可以抑制转化生长因子β1诱导的SiO2致肺成纤维细胞纤维连接蛋白合成,具有抗SiO2所致肺间质纤维化的潜在作用.     

过氧化物酶体增殖物激活受体γ激动剂对二氧化硅致成纤维细胞纤维连接蛋白表达的影响（英文）

背景：过氧化物酶体增殖物激活受体γ激动剂对转化生长因子β1致矽肺肺间质纤维化作用的影响及机制尚不明确,罕见报道。目的：观察过氧化物酶体增殖物激活受体γ激动剂对转化生长因子β1致矽肺肺纤维化作用的影响。方法：200mg/LSiO2刺激SD大鼠肺泡巨噬细胞培养上清液作用于中国仓鼠肺成纤维细胞株（CHL）建立矽肺纤维化的体外细胞模型。RT-PCR检测过氧化物酶体增殖物激活受体γ配体15d-PGJ2及其激动剂曲格列酮和齐格列酮对转化生长因子β1诱导CHL的纤维连接蛋白mRNA表达的影响。利用Western印迹技术观察过氧化物酶体增殖物激活受体γ激动剂对转化生长因子β1诱导CHL的纤维连接蛋白表达的影响。结果与结论：①转化生长因子β1mRNA表达呈一定范围内的剂量（0~5μg/L）和时间（0~24h）依赖效应。②过氧化物酶体增殖物激活受体γ配体及激动剂降低了纤维连接蛋白mRNA和蛋白的表达。结果提示过氧化物酶体增殖物激活受体γ激动剂可以抑制转化生长因子β1诱导的SiO2致肺成纤维细胞纤维连接蛋白合成,具有抗SiO2所致肺间质纤维化的潜在作用。     

Cell protection through PPAR nuclear receptor activation

Apart from their effects on lipid and glucose metabolism, the nuclear receptors PPARs (peroxysome proliferator-activated receptors) could also be involved in cellular protection. Indeed, an increasing body of literature provides arguments in favour of a protective role of PPAR alpha (fenofibrate, gemfibrozil) and PPAR gamma (ciglitazone, pioglitazone, rosiglitazone, troglitazone) agonists, particularly in myocardial or cerebral ischaemia as well as in neurodegenerative diseases. Such cellular protection could be the result of the modulation, at a molecular level, of inflammation pathways, oxidative stress and apoptosis. If these experimental results are confirmed by appropriate clinical trials, pharmacological modulation of the nuclear receptor PPARs, as well as the development of highly selective and more effective PPAR agonists, could become an important challenge in the field of cellular protection.     

六亚甲基二乙酰胺对HL-60细胞细胞周期及其调节蛋白表达的影响

六亚甲基二乙酰胺(hexamethylene bisecetamide,HMBA)是一种极性诱导分化剂，已应用于临床治疗急性髓系白血病和骨髓增生异常综合征(MDS)，但其诱导髓系白血病细胞分化的机制尚不清楚。本研究观察了HMBA对HL—60白血病细胞细胞周期及其调节蛋白表达的影响，以探讨其药理机制。用流式细胞术检测HMBA对HL—60细胞细胞周期分布和细胞周期蛋白D、E及p27表达的影响。用RT—PCR研究HMBA对细胞周期负性调控分子CKI p15，p16，p27基因mRNA表达的影响。结果表明，HMBA主要使HL—60细胞阻滞于G0/G1期，经HMBA处理后HL-60细胞胞浆内细胞周期蛋白E蛋白表达显降低，而细胞周期蛋白D和p27蛋白表达则显增高；未经HMBA处理的HL-60细胞p15，p16 mRNA均无表达；3mmol／L HMBA处理24小时后p15 mRNA出现弱阳性条带，48小时和72小时后出现强阳性条带，p16 mRNA则在48小时后出现弱阳性条带，72小时后出现强阳性条带；p27 mRNA在未经处理和处理后24，48和72小时后均出现强阳性条带，阳性程度无明显差异。结论：HMBA的药理机制之一可能是通过下调细胞周期蛋白E，上调p27蛋白的表达，同时使得p15，p16基因mRNA重获表达。阻滞HL—60细胞周期于G1期，从而发挥其抗增殖作用。     

塞来昔布对人白血病细胞株HL-60细胞增殖及凋亡的影响及其作用机制

本研究旨在探讨塞来昔布（celecoxib）对人急性髓系白血病细胞株HL-60细胞增殖、凋亡的影响及其可能的作用机制。不同浓度塞来昔布作用于HL-60细胞24h后,CCK-8法测定细胞增殖活性,流式细胞技术分析细胞凋亡及细胞周期分布的变化,定量RT—PCR的方法检测细胞周期蛋白DJ、EI及COX-2mRNA的表达。结果表明,不同浓度塞来昔布作用于HL-60细胞24h后,细胞增殖明显受抑,且呈-定的浓度依赖性（r=0．955）,24h的IC50值为63．037μmol／L。塞来昔布可诱导HL-60细胞的凋亡,也呈剂量依赖性（r=0．988）。塞来昔布可使HL-60细胞明显阻滞于G0／G1期,可下调cyclinD1、cyclinE1mRNA的表达。塞来昔布可使细胞COX-2mRNA表达水平降低。结论：塞来昔布呈浓度依赖性抑制HL-60细胞增殖,并可能通过下调cyclinD1、cyclinE1的表达引起细胞G0／G1,期阻滞,下调COX-2的表达诱导细胞凋亡。     

mPGES-1抑制剂MK886对白血病HL-60细胞周期的影响

本研究探讨膜结合型前列腺素E2合酶1(mPGES-1)抑制剂MK886对人急性髓系白血病HL-60细胞周期的作用。采用流式细胞仪分析技术、Western blot、ELISA等方法检测不同浓度MK886(10、25、50μmol/L)对HL-60细胞周期的作用及对细胞周期调控因子周期蛋白D1、mPGES-1、PGE2、Akt、P-Akt、C-MYC蛋白的影响。结果表明:与正常人外周血单个核细胞比较,G0/G1期HL-60细胞比例减少,S期比例增多。MK886作用24 h后,被阻滞于G0/G1期的细胞增多,同时细胞mPGES-1表达下调,合成PGE2减少,P-Akt、C-MYC、周期蛋白D1蛋白表达下降。结论:MK886对白血病HL-60细胞有细胞周期阻滞作用,其机制可能与抑制mPGES-1表达,减少PGE2的合成,抑制Akt磷酸化及C-MYC表达,下调周期蛋白D1表达有关。     

Peroxisome proliferator-activated receptor alpha and gamma ligands differentially affect smooth muscle cell proliferation and migration

Peroxisome proliferator-activated receptors (PPARs) alpha and gamma are expressed in smooth muscle cells (SMCs). This study was designed to compare the effects of PPARalpha and PPARgamma on SMC proliferation and migration and to determine how they operate. Treatment of SMCs from porcine coronary artery revealed that mitogen-stimulated DNA synthesis was blocked by the PPARalpha ligand 4-chloro-6-(2,3-xylidino)-2-pyrimidinylthioacetic acid (WY14,643) and 15-deoxy-Delta(12,14) prostaglandin J(2) (15d-PGJ(2)) (a putative PPARgamma agonist) but not by the PPARgamma agonist rosiglitazone or the PPARbeta/delta ligand 2-methyl-4-((4-methyl-2-(4-trifluoromethylphenyl)-1,3-thiazol-5-yl)-methylsulfanyl)phenoxy acetic acid (GW501516). Inhibition of DNA synthesis by clofibrate and 2-(4-(2-(1-cyclohexanebutyl-3-cyclohexylureido)ethyl)phenylthio)-2-methylproprionic acid (GW7647) confirmed that SMC proliferation is affected by PPARalpha. This conclusion was supported by the fact that WY14,643 also inhibited the proliferation of H4IIE hepatoma cells (expressing only PPARalpha) but not A10 SMCs (expressing only PPARgamma1). In contrast, the effective inhibition of all cell types with 15d-PGJ(2) indicated that this compound probably operates via a PPARgamma-independent mechanism. Interestingly, rosiglitazone did not inhibit DNA synthesis of either H4IIE or A10 cells, suggesting that the activation of PPARgamma does not influence cell proliferation. Phosphorylation of cyclin-dependent kinase 2 and expression of proliferating cell nuclear antigen were inhibited by WY14,643 but not by rosiglitazone or 15d-PGJ(2), indicating that PPARalpha prevents progression into S phase. Although rosiglitazone did not block SMC proliferation, it (like WY14,643) reduced neointimal hyperplasia in vitro. This observation can be rationalized by the fact that both WY14,643 and rosiglitazone inhibit SMC migration, probably through matrix metalloproteinase 9. Our study therefore shows that selective interference with mediators of cell cycle progression and cell migration via activation of PPARs may prevent growth-related vascular diseases such as restenosis and atherosclerosis.     

Effect of cyclopentanone prostaglandin 15-deoxy-delta12,14PGJ2 on early functional recovery from experimental spinal cord injury

Peroxisome proliferator-activated receptor (PPAR) gamma is a member of the nuclear-receptor superfamily that binds to DNA with retinoid X receptors as PPAR-retinoid X receptor heterodimers. Recent evidence also suggests that the cyclopentenone prostaglandin 15-deoxy-DeltaPGJ2 (15d-PGJ2), which is a metabolite of the prostaglandin D2, functions as an endogenous ligand for PPAR-gamma We postulated that 15d-PGJ2 would attenuate inflammation, investigating the effects on the degree of experimental spinal cord trauma induced by the application of vascular clips (force of 24 g) to the dura via a four-level T5-T8 laminectomy. Spinal cord injury in mice resulted in severe trauma characterized by edema, neutrophil infiltration, production of a range of inflammatory mediators, tissue damage, and apoptosis. Furthermore, 15d-PGJ2 reduced (1) spinal cord inflammation and tissue injury (histological score), (2) neutrophil infiltration (myeloperoxidase activity), (3) nuclear factor-kappaB activation, (4) expression of iNOS, nitrotyrosine and TNF-alpha, and (5) apoptosis (terminal deoxynucleotidyltransferase-mediated uridine triphosphate end labeling staining, Bax, Bcl-2, and FAS-L expression). In a separate set of experiments, 15d-PGJ2 significantly ameliorated the recovery of limb function (evaluated by motor recovery score). To elucidate whether the protective effects of 15d-PGJ2 are related to activation of the PPAR-gamma receptor, we also investigated the effect of a PPAR-gamma antagonist, GW 9662, on the protective effects of 15d-PGJ2. GW9662 (1 mg/kg administered i.p. 30 min before treatment with 15d-PGJ2) significantly antagonized the effect of the PPAR-gamma agonist and, thus, abolished the protective effect. Taken together, our results clearly demonstrate that treatment with 15d-PGJ2 reduces the development of inflammation and tissue injury associated with spinal cord trauma.     

Peroxisome proliferator-activated receptor ligands as antiatherogenic agents: panacea or another Pandora's box?

Peroxisome proliferator activated receptors (PPARs) are members of the nuclear receptor super family that modulate gene expression upon ligand activation. They are 3 major subtypes of PPARs: alpha, delta (also called beta), and gamma. PPAR-gamma is widely expressed in the cardiovascular system and is involved in the regulation of tissue inflammation and smooth muscle cell growth pathways as well as in lipoprotein metabolism and coagulation cascades. PPAR-gamma ligands of (e.g., rosigitazone and pioglitazone) have been shown to exert antiatherogenic effects both in vitro and in vivo. PPAR-alpha ligands (e.g., clofibrate and benzofibrate) modulate lipoprotein metabolism, and affect inflammation and coagulation cascade. These effects may be helpful in resolving the dilemma arising from studies that showed significant mortality and morbidity benefits of fibrates in the face of minimal changes in HDL-cholesterol levels. The role of PPAR-delta in atherogenesis remains largely unknown, although it appears that PPAR-delta activation affects lipoprotein metabolism. PPAR ligands appear to be promising agents in limiting atherosclerosis; however, large-scale clinical trials are required to assess their safety and efficacy before they can be added to the clinicians' arsenal of antiatherosclerotic agents.     

周期蛋白G1反义硫代脱氧寡核苷酸对白血病细胞增殖的调控

为了探讨脂质体转染细胞周期蛋白(cyclin)G1反义脱氧寡核苷酸(ASON)对HL-60细胞增殖调控的作用，用针对cyclin G1 mRNA5′端编码区起始密码子(ATG／AUG)的ASON，通过脂质体导入HL-60细胞共培养后，用免疫组织化学法和RT-PCR分别检测cyclin G1和mRNA水平的表达，用电镜、细胞原位凋亡检测法(POD)、流式细胞术(FCM)及DNA凝胶电泳等方法检测细胞凋亡。结果表明：cyclin G1 ASON组与SON及空白对照组相比，ASON能特异地抑制cyclin G1及mRNA水平的表达，当ASON的浓度达到一定程度时，HL-60细胞的增殖及集落形成率均明显受抑制，出现细胞凋亡，并且此作用随ASON浓度的升高而增强。结论：cyclin G1的特异反义脱氧寡核苷酸能封闭其蛋白及mRNA水平的表达，对白血病细胞的增殖有抑制作用，并可促使细胞凋亡，且有浓度依赖性。