胰岛素抵抗细胞模型的研究进展

胰岛素抵抗是产生2型糖尿病、心血管疾病、高脂血症、高尿酸血症及代谢综合症的共同病理基础.构建胰岛素抵抗细胞模型是进行IR相关疾病的病理机制探索及药物研发的重要途径.IR产生机制尚未阐明,现已证实糖脂代谢紊乱,高胰岛素持续刺激.炎症微环境等因素均可导致IR.收也将此作为IR细胞模型建立刺激因素.目前已建立肪细胞、骨骼肌细...     

葛根调节脂肪细胞糖脂代谢改善胰岛素抵抗的研究

该实验通过检测葛根对胰岛素抵抗(IR)3T3-L1脂肪细胞葡萄糖消耗,甘油三脂(TG)含量及PPARγ,ADPN,GLUT4,LPL,FABP4,FASn表达量的影响来探讨葛根调节糖脂代谢改善脂肪IR的作用机制。先采用3T3-L1前脂细胞诱导分化的成熟脂肪细胞,地塞米松诱导建立IR模型,将脂肪细胞分为正常组,IR模型组,罗格列酮阳性组,低、中、高剂量葛根含药血清组,以葡萄糖氧化酶-过氧化物酶(glucose oxidase-peroxidase,GOD-POD)法检测细胞培养液葡萄糖含量和甘油磷酸氧化酶(glycerol phosphate oxidase,GPO-POD)法测定胞内TG含量,荧光定量q PCR检测PPARγ,ADPN,GLUT4,LPL,FABP4(a P2),FASn基因mRNA水平。结果显示1μmol·L~(-1)地塞米松作用3T3-L1脂肪细胞96 h,与正常组比较,模型组葡萄糖消耗量降低(P0.01),胞内TG含量增加(P0.01),由此确认建立IR模型;与IR组比较,葛根含药血清干预IR细胞24 h葡萄糖消耗量上升(P0.01),胞内TG含量降低(P0.01),中、高剂量葛根含药血清组升高PPARγ,ADPN和GLUT4表达(P0.01),PPARγ与后两者基因表达呈现一致性。脂代谢相关基因检测结果显示仅高剂量葛根含药血清显著升高LPL表达(P0.05);各剂量葛根含药血清下调FABP4表达(P0.01);中、高剂量的葛根含药血清上调FASn基因表达(P0.01)。该实验表明葛根提高IR-3T3-L1脂肪细胞对葡萄糖的摄取能力,降低细胞内TG积聚,干预多个重要糖脂代谢基因,推测以PPARγ为中心多靶点调节糖脂代谢改善脂肪IR。     

GW4064, a farnesoid X receptor agonist,upregulates adipokine expression in preadipocytes and HepG2 cells

AIM: To investigate the effect of GW4064 on the expression of adipokines and their receptors during differentiation of 3T3-L1 preadipocytes and in HepG2 cells.METHODS: The mRNA expression of farnesoid X receptor (FXR), peroxisome proliferator-activated receptor-gamma 2 (PPAR-γ2), adiponectin, leptin, resistin, adiponectin receptor 1 (AdipoR1), adiponectin receptor 2 (AdipoR2), and the long isoform of leptin receptor (OB-Rb) and protein levels of adiponectin, leptin, and resistin were determined using fluorescent real-time PCR and enzyme linked immunosorbent assay, respectively, on days 0, 2, 4, 6, and 8 during the differentiation of 3T3-L1 preadipocytes exposed to GW4064. Moreover, mRNA expression of AdipoR2 and OB-Rb was also examined using fluorescent real-time PCR at 0, 12, 24, and 48 h in HepG2 cells treated with GW4064.RESULTS: The mRNA expression of FXR, PPAR-γ2, adiponectin, leptin, resistin, AdipoR1, AdipoR2, and OB-Rb and protein levels of adiponectin, leptin, and resistin increased along with differentiation of 3T3-L1 preadipocytes (P < 0.05 for all). The mRNA expression of FXR, PPAR-γ2, adiponectin, leptin, and AdipoR2 in 3T3-L1 preadipocytes, and AdipoR2 and OB-Rb in HepG2 cells was significantly increased after treatment with GW4064, when compared with the control group (P < 0.05 for all). A similar trend was observed for protein levels of adipokines (including adiponectin, leptin and resistin). However, the expression of resistin, AdipoR1, and OB-Rb in 3T3-L1 cells did not change after treatment with GW4064.CONCLUSION: The FXR agonist through regulating, at least partially, the expression of adipokines and their receptors could offer an innovative way for counteracting the progress of metabolic diseases such as nonalcoholic fatty liver disease.     

Primary skeletal non-Hodgkin's lymphoma in the pediatric age group

The authors discuss rare primary skeletal non-Hodgkin's lymphoma in 16 patients treated from 1973 to 1989. The symptoms of these patients related to bone lesions in 95% of the cases. These bone lesions were monostotic or polyostotic, with or without regional and distant metastases. The locations of these lesions were long bones in 13 patients, pelvic bones in seven patients, and skull and vertebral bodies in two patients. The anatomical locations of these lesions in the bones were diaphysis alone in one patient, epiphysis in two patients, metaphysis in three patients, and a combination of diaphyseal, epiphyseal, and metaphyseal lesions in seven patients. Extraskeletal involvement was present in nine patients; extraskeletal sites included regional or distant lymph node involvement in seven cases, the mediastinum in two, lung nodules in two patients, the skin and subcutaneous regions in four patients; bone marrow in three patients, and peripheral nervous system (PNS) in one patient. Two patients had stage I disease, three had stage II disease, eight had stage III disease, and three had stage IV disease. The majority of patients had large noncleaved cell diffuse lymphomas or DHL by Rappaport classification. All patients were treated with the LSA₂-L₂ protocol; six patients received radiation therapy to the affected bone, and ten patients received no radiation therapy. Three patients failed on treatment within the first 4 months of therapy. Two patients developed a second tumor, one in the radiation therapy field and the other in a patient who received no radiation therapy. Eleven patients are alive without evidence of disease, with a median observation time of 6.5 years. The event-free survival for the 16 patients receiving LSA₂-L₂ was 73%, and the lymphoma-free survival was 81%. Extension of disease to multiple sites or location of the primary site was not of prognostic significance, but the finding of central nervous system (CNS), PNS, or bone marrow disease at diagnosis was. Whether the skeletal lesions were uni- or multifocal, with regional or distant metastases, the prognosis for lymphoma-free survival was good. The role of radiation therapy for all patients and intensive treatment for earlystage disease is discussed. The authors conclude that chemotherapy is the most important modality of treatment for any stage, histology, or location of the tumor. This chemotherapy shou ld include drugs that have been shown to be effective in the treatment of pediatric lymphoma, such as cyclophosphamide, cytosine arabinoside, vincristine, methotrexate, and daunomycin, in dosages sufficient to produce marrow suppression and early recovery, allowing for continuous or intermittent therapy. Radiation therapy should be used if there is no response or progression of disease (demonstrated either clinically or by scans, confirmed by a biopsy) within the first few months of treatment. © 1992 Wiley-Liss, Inc.     

Non-Hodgkin's lymphoma in children

In a study of non-Hodgkin's lymphoma in children, 104 children were treated and followed at Memorial. Sloan-Kettering Cancer Center from 1964 through June 1974. Forty-three patients, previously treated and untreated, received a nonspecific group of various chemotherapeutic agents and attained an 11% disease-free survival rate. A second group of 18 previously untreated patients, who received a chemotherapeutic regimen consisting of cyclophosphamide alone, achieved a 33% disease-free survival rate. The last group, 43 previously untreated patients (77% of whom had far advanced disease and 86% of whom had diffuse histological types) who received a new and intensive multiple-drug regimen (the LSA₂-L₂ protocol) consisting of induction, consolidation, and maintenance phases, has maintained an 81% disease-free survival rate after a median observation time of 21+ months. Although nervous system involvement and recurrence or metastases at any time are poor prognostic factors, initial marrow involvement and the amount of bulky disease are no longer considered negative prognosticators when intensive treatment is initiated immediately after diagnosis, is continued for 2 - 3 years, and includes radiation therapy to sites of bulky disease and CNS prophylaxis. The LSA₂-L₂ treatment is effective in accomplishing the dual aims of not only increasing the numbers of disease-free patients but also prolonging their survival.     

胰岛素受体底物1基因沉默对3T3-L1细胞CCAAT增强子结合蛋白α、过氧化物酶体增殖物激活受体γ表达的影响

目的研究胰岛素受体底物1(IRS-1)沉默对3T3-L1前脂肪细胞分化关键分子CCAAT增强子结合蛋白α(C/EBPα)、过氧化物酶体增殖物激活受体γ(PPARγ)mRNA及蛋白表达的影响,并观察IRS-1沉默后前脂肪细胞分化为成熟脂肪细胞能力的改变,探讨胰岛素受体底物(IRSs)是否作为C/EBPα、PPARγ的上游调节信号在前脂肪细胞分化中起到重要的调节作用。方法合成4条IRS-1 shRNA,Western blotting筛选出沉默效率最高的1条。3T3-L1前脂肪细胞分为IRS-1沉默组和对照组。IRS-1沉默组细胞用沉默效率最高的IRS-1 shRNA质粒转染3T3-L1前脂肪细胞,沉默细胞中的IRS-1分子;对照组采用无意义IRS-1 shRNA质粒转染3T3-L1前脂肪细胞。转染24 h后诱导其分化成熟,分化72 h后检测促进前脂肪细胞分化的关键分子C/EBPα、PPARγ的表达。继续诱导分化至第7天,油红O染色观察IRS-1沉默后前脂肪细胞分化为成熟脂肪细胞的比例,检测其分化能力的改变。结果与对照组相比,IRS-1沉默组在诱导分化72 h后,Real-time PCR结果显示3T3-L1前脂肪细胞中C/EBPαmRNA、PPARγmRNA表达明显下降(Pa<0.05),Western blotting结果显示C/EBPα、PPARγ蛋白水平也同样显著下降(Pa<0.05);细胞继续分化至第7天,油红O染色显示,IRS-1沉默组前脂肪细胞分化成熟的比例与对照组比较显著降低。结论胰岛素可能通过IRS-1刺激C/EBPα、PPARγ的表达促进前脂肪组织的分化。     

MiR-24对3T3-L1脂肪细胞分化及脂肪型脂肪酸结合蛋白表达的调节作用

目的探讨microRNAs对脂肪细胞分化过程的调节作用分子机制及其对脂肪特异性基因——脂肪型脂肪酸结合蛋白(fatty acid binding protein,FABP4)表达的影响。方法用microRNAs微阵列分析法筛选和鉴定3T3-L1脂肪细胞分化相关性microRNAs,构建脂肪细胞分化相关性micro-RNAs的高表达质粒,通过脂质体介导转染3T3-L1前体脂肪细胞,观察脂肪相关性microRNAs对脂肪细胞分化过程的影响,Westernblot和RT-PCR分别检测FABP4蛋白及其mR-NA在脂肪细胞分化过程中的表达变化。结果3T3-L1脂肪细胞分化过程中microRNA表达谱发生明显改变,其中35个microRNAs下调,miR-24最明显;17个microRNAs上调,miR-21最明显;用不同脂肪相关性microRNAs转染3T3-L1前体脂肪细胞并高表达后,发现miR-24明显抑制脂肪细胞的分化与成熟,而miR-21则无影响;miR-24明显抑制FABP4蛋白表达,但对其mRNA无影响,miR-21对FABP4的蛋白和mRNA表达都没有影响。结论3T3-L1脂肪细胞分化过程中存在脂肪细胞分化相关性microRNAs;miR-24脂肪细胞分化过程及其脂肪特异蛋白FABP4表达有重要的调节作用。     

高糖高脂肪酸环境下维生素D对分化后前脂肪细胞脂肪合成的影响

目的 探讨在高糖、高脂肪酸环境下维生素D的活性形式1,25（OH）2 D3（VD3）对分化后前脂肪细胞脂肪合成的影响.方法 将前脂肪细胞3T3-L1细胞分为对照组（C组）、高糖组（G组）和高糖高脂肪酸组（GF组）后进行诱导分化,观察加入VD3后最终成熟脂肪细胞中脂肪含量的改变,采用油红O染色和异丙醇萃取法半定量检测细胞内脂肪含量;用RT-PCR法检测各组细胞维生素D受体（VDR）、固醇调节元件结合蛋白-1c（SREBP-1c）和激素敏感脂肪酶（HSL） mRNA的表达水平.结果 与C组比较,G组和GF组脂肪细胞内脂肪含量明显增高（P＜0.05）,VD3可减少C组脂肪含量（P＜0.05）,但是对G组和GF组脂肪含量无影响（P＞0.05）.与C组比较,G组和GF组VDR mRNA表达降低（P＜0.05）,VD3可提高三组细胞VDR mRNA的表达（P＜0.05）.与C组比较,G组和GF组的SREBP-1c、HSL mRNA表达升高（P＜0.05）;VD3减少C组SREBP-1c mRNA水平,对G组和GF组的SREBP-1c、HSL以及C组的HSL mRNA无影响（P＞0.05）.结论 在高糖、高脂肪酸的环境下,VD3已失去对前脂肪细胞脂肪合成的抑制作用.