载脂蛋白C-Ⅲ基因沉默对HepG2细胞脂代谢的影响

目的:研究RNAi技术沉默载脂蛋白C-Ⅲ基因(ApoC3)表达后对HepG2细胞内外脂质含量及其他脂代谢相关基因表达的影响。方法:合成3对针对ApoC3mRNA不同位点序列的小干扰RNA(siRNA),并分组转染至人肝细胞株HepG2,实时荧光定量PCR和酶联免疫吸附法检测ApoC3mRNA及蛋白质的表达水平,筛选出沉默效果最佳的一对siRNA。将最有效的siRNA转染HepG2细胞,48h后测定细胞内外脂质含量以及脂代谢相关基因的mRNA表达水平。结果:25nmol/L siRNA和3μl/孔(24孔板)转染试剂的转染效率最高。ApoC3-siRNA-3对ApoC3基因的沉默效果最好,对mRNA的抑制率为94.6%,上清液中检测不到ApoC-Ⅲ。ApoC3-siRNA-3沉默ApoC3基因后细胞内三酰甘油(TG)和胆固醇含量显著高于对照组,细胞外TG含量显著低于对照组。与对照组比较,ApoC3-siRNA-3沉默组载脂蛋白B100基因mRNA表达水平显著增强,肝脂酶基因mRNA表达水平显著降低。结论:ApoC3基因沉默可显著升高HepG2细胞内TG含量及显著降低细胞外TG含量,其可能机制是通过减少极低密度脂蛋白(VLDL)颗粒的分泌以及增加VLDL残粒的摄取。     

小干扰RNA沉默甲胎蛋白基因对HepG2细胞迁移及侵袭的影响

目的研究甲胎蛋白(AFP)对肝癌HepG2细胞迁移和侵袭能力的影响及其机制。方法应用合成的靶向沉默AFP小干扰RNA(siRNA)转染肝癌HepG2细胞,分为空白对照、阴性对照组及AFP siRNA组,各组细胞干预48 h后,采用实时定量PCR(qRT-PCR)和ELISA法检测细胞转染后的沉默效率,Transwell小室实验检测沉默AFP基因后HepG2细胞的侵袭、迁移能力,用Western blotting法观察沉默AFP基因的表达对上皮-间质转化(EMT)相关蛋白(N-cadherin、Vimentin和E-cadherin)、AKT和p-AKT蛋白表达的影响。计量资料多组间比较采用单因素方差分析,进一步两两比较采用LSD-t检验。结果转染沉默后,与空白对照组相比,AFP siRNA组中AFP mRNA的相对表达量明显降低(P 0.01),抑制率达86.440%,同时AFP siR NA组细胞上清液中AFP蛋白表达水平同样明显降低(P 0.01)。与空白对照组相比,AFP siRNA组的迁移细胞数和侵袭细胞数显著下降,差异具有统计学意义(P值均0.01)。沉默HepG2细胞中AFP基因的表达后,与空白对照组比较,AFP siRNA组EMT相关蛋白E-cadherin蛋白的表达水平升高(P 0.01),而N-cadherin及Vimentin表达水平均明显降低(P值均0.05),且PI3K/AKT信号通路相关蛋白p-AKT的表达水平明显降低(P 0.01)。结论沉默AFP可抑制肝癌细胞转移,基于HepG2细胞株的机制研究可能与阻断PI3K/Akt通路抑制EMT相关。     

siRNA干扰沉默EZH2基因对人肝癌HepG2细胞增殖的影响

目的探讨小分子RNA(siRNA)干扰沉默靶基因EZH2对人肝癌HepG2细胞增殖的影响。方法取对数生长期的HepG2细胞,分为转染组、阴性对照组及空白对照组,转染组与阴性对照组按照Lipofectamine2000使用说明分别瞬时转染EZH2 siRNA、荧光物FAM,对照组不予任何干预。分别采用MTT法检测细胞增殖活性、流式细胞仪检测细胞凋亡率及周期;qRealtime-PCR和Western blot方法检测EZH2 mRNA和蛋白表达。结果与阴性对照组相比,转染组细胞增殖明显受抑;与阴性对照组及空白对照组比较,转染组细胞凋亡率明显升高,G0/G1期细胞明显增多,S期明显细胞减少;转染组EZH2 mRNA和蛋白表达明显下调,P均<0.05。结论 EZH2 siRNA可抑制人肝癌细胞增殖活性,是一种潜在基因治疗新方法。     

siRNA沉默Cyclin E基因对肝癌HepG2、SMMC-7721和BEL-7402细胞增殖和侵袭能力的影响

目的:观察siRNA沉默Cyclin E基因表达对肝癌HepG2、SMMC-7721和BEL-7402细胞增殖和侵袭能力的影响.方法:构建2个靶向Cyclin E基因siRNA载体,转染人肝癌HepG2、SMMC-7721和BEL-7402细胞.RT-PCR、Western blot检测转染后HepG2、SMMC-7721和BEL-7402细胞Cyclin E基因mRNA和蛋白表达水平.CCK-8试验、软琼脂克隆形成实验检测HepG2、SMMC-7721和BEL-7402细胞增殖、克隆形成能力.流式细胞术、transwell试验分别检测HepG2、SMMC-7721和BEL-7402细胞周期和侵袭能力.结果:构建的2个Cyclin E基因siRNA载体插入序列与所设计序列均一致;转染HepG2、SMMC-7721和BEL-7402细胞后,干扰1组、干扰2组与空白对照组和阴性对照组比较,C y c l i n E m R N A和蛋白表达量均显著降低(P<0.05),细胞生长速度延缓,软琼脂细胞集落形成数、穿透细胞数均显著降低(P<0.05),S和G2/M期细胞比例减少,G0/G1期细胞比例增加.结论:沉默肝癌细胞Cyclin E表达水平,可有效抑制细胞生长、增殖和侵袭能力.     

IL-6对肝癌细胞HepG2浸润迁移能力的影响

目的观察肝癌细胞系HepG2自身分泌的白细胞介素-6(interleukin-6,IL-6)对其浸润迁移能力的影响。方法 RNA干扰技术沉默IL-6,同时设空白对照组(不加转染试剂)、正常对照组(转染空脂质体)、无义对照组(转染无义对照siRNA)、实验对照组(转染沉默IL-6的siRNA)。进行细胞划痕损伤实验检测细胞的迁移能力。结果 RT-PCR检测各组IL-6 mRNA的表达分别为100±7.87、303±19.95、160±10.95、23±7.02;IL-6在沉默组细胞的浸润迁移能力受到抑制,正常对照组(转染空脂质体)、无义对照组(转染无义对照siRNA)细胞的浸润迁移能力增强。结论 IL-6被沉默能抑制肝癌细胞系HepG2的迁移,肝癌细胞系HepG2IL-6表达增高能促进其自身发生迁移。     

siRNA沉默Livin基因对胃癌细胞生长、凋亡的影响

目的:观察小分子干扰RNA(siRNA)沉默Livin基因在胃癌BGC-823细胞中的表达, 并探讨Livin基因对胃癌细胞生长、凋亡的影响.方法:自行设计两条针对Livin基因的siRNA:Livin-sh-1和Livin-sh-2, 以此构建相应的表达载体并分别转染至对数生长期胃癌BGC-823细胞, 经G418筛选后分别采用半定量RTPCR检测不同siRNA实验分组细胞BGC-823mRNA水平变化, 四氮唑盐比色法(MTT)检测细胞增殖、流式细胞仪检测胃癌细胞的凋亡.结果:siRNA对照组与空siRNA载体组Livinα/β mRNA表达差别无显著性; 但转染siRNA组Livin α/β mRNA表达显著低于空白对照组和空siRNA载体组(Livin α:0.11±0.07 vs 0.37±0.10, 0.34±0.08; Livin β:0.13±0.04 vs 0.43±0.09, 0.45±0.11, 均P<0.05). 空白对照组与空siRNA载体组相比, 24、48、96 h和1 wk时细胞生长未受影响; 而siRNA组在转染后24 h和48 h细胞生长未受影响, 但在96 h和1 wk时则被明显抑制( P<0.01). 转染siRNA组的细胞的凋亡率与空白对照组和转染空siRNA载体组相比显著增加(14.85%±1.35% vs 4.51%±0.36%, 6.13%±0.71%, 均P<0.05).结论:siRNA沉默Livin基因能抑制胃癌细胞的生长, 促进胃癌细胞的凋亡, Livin基因有可能成为胃癌治疗的新靶点.     

siRNA沉默Annexin-1基因对膀胱癌T24细胞生物学特性的影响

目的观察RNA干扰技术沉默Annexin-1基因表达对膀胱癌T24细胞增殖能力的影响。方法针对Annexin-1基因不同部位设计并化学合成3对不同的靶向小干扰RNA(siRNA),脂质体介导瞬时转染膀胱癌T24细胞,转染后应用半定量RT-PCR和Western印迹法检测Annexin-1mRNA和蛋白的改变,透射电镜观察细胞凋亡情况,用MTT法检测沉默Annexin-1表达对膀胱癌T24细胞增殖的影响。结果转染siRNA后膀胱癌T24细胞Annexin-1mRNA和蛋白水平显著下降(P0.05),转染siRNA沉默Annexin-1基因表达后膀胱癌T24细胞出现典型凋亡细胞,增殖能力显著下降(P0.05)。结论 RNA干扰Annexin-1基因后其mRNA和蛋白水平显著下降,诱导了膀胱癌T24细胞凋亡,并且抑制细胞的增殖。     

IL-6上调SCD1表达对HepG2细胞脂质合成功能的影响

目的探讨IL-6对HepG2细胞硬脂酰辅酶A去饱和酶1(SCD1)基因的影响及其SCD1基因表达的改变对细胞脂质合成的影响。方法应用rIL-6刺激HepG2细胞,检测细胞内脂质合成以及细胞SCD1基因水平变化。分别构建人SCD1真核表达质粒和小干扰(small interfering) RNA,转染HepG2细胞,观察改变SCD1水平后HepG2细胞脂代谢相关基因表达的变化以及细胞内脂质合成的变化。结果 rIL-6刺激HepG2细胞甘油三酯水平显著高于对照组(P0.05);与空质粒组比,转染真核表达质粒细胞SCD1蛋白表达增加,细胞脂质合成相关基因SREBP1c和FASN相对水平增加1.35倍和1.27倍,脂质氧化代谢相关基因PPARα和ASCL3水平降低12.3%和13.5%;细胞甘油三酯水平显著升高(P0.01),而转染small interfering RNA,再用rIL-6刺激HepG2细胞SCD1蛋白表达显著降低,细胞甘油三酯水平也显著降低(P0.05),脂质合成相关基因SREBP1c和FASN水平显著下降了32.3%和51.9%,脂质分解相关基因PPARα相对水平也下降了80%(P0.05),而ASCL3水平无显著变化(P=0.832)。结论 rIL-6通过上调HepG2细胞SCD1基因表达,引起细胞内脂质合成增加,导致甘油三酯含量增多。     

靶向cyclinE小干扰RNA对肝癌HepG2细胞增殖和凋亡的影响

目的:以cyclinE基因编码区为靶位,构建表达小干扰RNA(siRNA)的质粒载体,观察转染后对HepG2细胞的影响.方法:针对cyclinE基因序列构建表达siRNA的真核表达载体pSilencer3.1-H1hygro,利用脂质体Metafectene转染CyclinE基因高表达的肝癌细胞株HepG2.流式细胞仪检测细胞周期及凋亡率,MTT法检测细胞增殖活性,RT-PCR和Western blot法观察转染后细胞cyclinE基因表达.结果:成功构建了表达siRNA的真核质粒载体,转染后cyclinE基因mRNA及蛋白表达水平分别下降了79%和65%.结论:靶向cyclinE基因的siRNA可有效沉默HepG2细胞高表达的cyclinE基因,从而抑制肝癌细胞的增殖并促进凋亡.     

Visfatin基因表达下调对小鼠脂肪细胞及肝细胞脂代谢的影响

目的探讨Visfatin基因表达抑制对小鼠脂肪细胞及肝细胞脂代谢相关基因的影响。方法构建并筛选具有最佳抑制率的pGene-sil-Visfatin表达载体,转染小鼠3T3-L1脂肪细胞及Hepa1-6肝细胞,Western印迹法测定两种细胞的Visfatin蛋白水平,实时荧光定量PCR法测定Vis-fatin、脂代谢相关基因的mRNA表达水平,油红O染色法测定脂肪细胞内甘油三酯(TG)含量变化。结果 pGenesil-visfatin可有效抑制两种细胞Vis-fatin蛋白表达。脂肪细胞转染pGenesil-Visfatin后,脂代谢相关基因PPARα/γ,HSL,ATGL,AP2,SREBP1,FAS,ACC mRNA表达均下降(其中PPARγ与ACC P<0.05,余P<0.001),TG含量降低,但无统计学差异;肝细胞转染后,PPARα,SREBP1,FAS以及SREBP2,HMGCR,LDLr mRNA表达显著降低(P<0.001),而HSL,ATGL与ACC变化无统计学意义(P>0.05)。结论 Visfatin基因表达下调可能对细胞脂质代谢具有调节作用。     

The immunoneuroendocrine role of melatonin

Abstract: A tight, physiological link between the pineal gland and the immune system is emerging from a series of experimental studies. This link might reflect the evolutionary connection between self-recognition and reproduction. Pinealectomy or other experimental methods which inhibit melatonin synthesis and secretion induce a state of immunodepression which is counteracted by melatonin. In general, melatonin seems to have an immunoenhancing effect that is particularly apparent in immunodepressive states. The negative effect of acute stress or immunosuppressive pharmacological treatments on various immune parameters are counteracted by melatonin. It seems important to note that one of the main targets of melatonin is the thymus, i.e., the central organ of the immune system. The clinical use of melatonin as an immunotherapeutic agent seems promising in primary and secondary immunodeficiencies as well as in cancer immunotherapy. The immunoenhancing action of melatonin seems to be mediated by T-helper cell-derived opioid peptides as well as by lymphokines and, perhaps, by pituitary hormones. Melatonin-induced-immuno-opioids (MHO) and lymphokines imply the presence of specific binding sites or melatonin receptors on cells of the immune system. On the other hand, lymphokines such as -γ-interferon and interleukin-2 as well as thymic hormones can modulate the synthesis of melatonin in the pineal gland. The pineal gland might thus be viewed as the crux of a sophisticated immunoneuroendocrine network which functions as an unconscious, diffuse sensory organ.     

Response of rat pineal melatonin to calcium, magnesium, and lithium is circadian stage dependent

Abstract: Herein we documented the response of pineal melatonin production to electrolytes known to be effective on pineal function in view of a possible circadian stage dependence. We studied the release of melatonin by perifused rat pineal glands at 2 different circadian stages corresponding to the middle of the light and dark periods, i.e., respectively, 7 and 19 HALO (Hours After Light Onset, L:D = 12:12). The initial efflux rates were, as expected, much higher in the perifusates of glands removed from rats sacrificed during the dark phase than of those removed during the light phase. After 3 hr of perifusion, melatonin release reached similar levels which were found constant up to the 8th hr of perifusion, whatever the circadian stage. Perifusion of the glands with physiological concentrations for the rat of calcium (5.2 mmol/1) and magnesium (1.34 mmol/1) resulted in a stimulatory effect on the pineal glands removed from rats sacrificed in the middle of the dark period (19 HALO), whereas no effects were observed on the pineal glands removed from rats sacrificed during the light (7 HALO). Lithium (0.28 and 0.55 mmol/1) was ineffective on melatonin release in pineal glands removed 7 and 19 HALO. Our results show differences in the initial efflux rates of melatonin and in the response of perifused pineal glands to calcium and magnesium according to the circadian stage.     

Changes in connexin43, the gap junction protein of astrocytes, during development of the rat pineal gland

Abstract: The abundance of gap junctions between rat pineal astrocytes formed by connexin43 (Cx43) was studied during development. Levels and distribution of Cx43 were measured by immunoblotting and indirect immunofluorescence, respectively. The amount of Cx43 in cells located within the gland was low until about the 7th postnatal day and increased to adult values between the 14th and 21st days postpartum. Although astrocytes, recognized by their vimentin immunoreactivity, were scarce before birth, they were abundant by the 7th postnatal day suggesting that the low levels of Cx43 found at this age corresponded to a low expression of this protein. Localization of the immunoreactivity to Cx43 and vimentin showed a close correlation, indicating that mature or immature pineal astrocytes form gap junctions made of Cx43. Since Cx43 levels attained their adult values at about the time the innervation and the functional state of the gland reached maturity (2–3 weeks after birth), it is proposed that astrocyte gap junctions are involved in the function of the adult rat pineal gland.     

Conservative management of perforated duodenal diverticulum： A case report and review of the literature

Duodenal diverticula are a relatively common condition. They are asymptomatic, unless they become complicated, with perforation being the rarest but most severe complication. Surgical treatment is the most frequently performed approach. We report the case of a patient with a perforated duodenal diverticulum, which was diagnosed early and treated conservatively with antibiotics and percutaneous drainage of secondary retroperitoneal abscesses. We suggest this method could be an acceptable option for the management of similar cases, provided that the patient is in good general condition and without septic signs.     

Presence of immunoreactive growth hormone and prolactin in the ovine pineal gland

Abstract: The use of antisera raised against bovine growth hormone (GH) and ovine prolactin (PRL) enabled the detection of related immunoreactive (ir) sequences of proteins in ovine pineal tissue. The isolation of PRL-like ir-material was accomplished using a 0.25 M ammonium sulphate (pH 5.5) extraction followed by ethanol precipitation, whereas the resulting 2.0 M ammonium sulphate (pH 7.0) precipitate contained a GH-like immunoreactivity. Gel chromatography of the GH-like immunoreactivity (Sephadex G-100) indicated the presence of several GH-like fragments ranging in the M_r range of 7,000 to 55,000. Analyses of the PRL-like ir-material found in pineal tissue on HPLC using a TSK 545-DEAE column led to the resolution into a single peak of immunoreactivity. A single peak of activity was also observed following chromatofocusing and hydrophobic interaction chromatography of the ir-peak from the TSK 545-DEAE column. The PRL-like ir-material inhibited the binding of [¹²⁵I]ovine PRL-S14 to anti-ovine PRL antibodies without showing an affinity for binding to anti-rat PRL or anti-bovine GH antibodies. Scatchard analysis of the binding of pineal PRL-like ir-material and pituitary ovine PRL-S14 to liver membranes from day-20 pregnant rats revealed similar affinity constants (K_a of 4.7 ± 0.2 × 10⁹ M^-1). In addition, the replication of Nb 2 Node rat lymphoma cells was stimulated by pineal PRL-like ir-material, an effect known to be specific for lactogenic hormones. The pineal PRL-like immunoreactivity appeared on sodium dodecyl sulfate polyacrylamide gels as a single major band of M_r 24,000. The functional status of PRL-and GH-like ir-material in the ovine pineal remains to be determined, but evidence is presented that the overall protein synthesis rate of the rat pineal responded to circulating concentrations of PRL.     

Microbiology of human immunodeficiency virus anorectal disease

PURPOSE: Individuals who are seropositive for the human immunodeficiency virus are at high risk for opportunistic infection and anorectal disorders. Little prospective information is available regarding anorectal pathogens in these patients. METHODS: One hundred sixty-three HIV-seropositive patients presented to the colorectal clinic between 1989 and 1992. Forty-seven (29 percent) patients were thought to have an infectious process and were prospectively studied using a standardized multiculture protocol. RESULTS: Mean age was 33 (range, 19–59) years. All were male; high-risk behavior accounted for 87 percent of HIV transmissions. Presenting complaints included anorectal pain (79 percent), pus per anum (28 percent), and blood per anum (26 percent). Examination revealed perianal tenderness (60 percent), condyloma (38 percent), perianal ulcers (38 percent), and anal fissures (34 percent). Sixty-six sets of cultures were performed; 28 patients had one set, 15 had two sets, and 4 had three sets. Thirty-two of these 47 patients (68 percent) had positive cultures including herpes (50 percent), cytomegalovirus (25 percent),Neisseria gonorrhoeae (16 percent), chlamydia (16 percent), acidfast bacilli (2 percent), and others (9 percent). Six of 32 patients with positive cultures had more than one organism cultured. Sixteen (50 percent) patients with positive cultures were treated medically, 8 (25 percent) were treated surgically and 8 (25 percent) were treated with both modalities. Sixty-one procedures were performed on 17 patients for condylomata. Eighteen patients had 20 procedures for abscesses, 50 percent of whom had positive cultures for other than common bowel flora; all improved. Fourteen patients underwent 33 procedures for perianal fistulas.Mycobacterium fortuitum was cultured from one patient who required 13 procedures for abscesses and fistulas. Forty-five (96 percent) patients were followed for an average of 12.5 months ±2.9 SEM (range, 1–94 months). Symptoms were improved or resolved in 22 of 32 (69 percent) patients with positive cultures and in 11 of 13 (84 percent) with negative cultures. CONCLUSIONS: Specific pathogens may often be identified in human immunodeficiency virus-seropositive patients with anorectal disorders if aggressively sought. Although patients without specific pathogens identified may be expected to improve with planned empiric treatment, positive identification allows more directed therapy.