PPARγ2基因Pro12Ala多态性与DM2-N易患性的关系

目的:研究我国北方汉族人群PPARγ2基因Pro12Ala多态性与2型糖尿病肾病(DM2-N)易患性的关系.方法:应用聚合酶链式反应-限制性片段长度多态性(PCR-RFLP)方法检测了78例2型糖尿病(DM2)患者(糖尿病肾病组患者41例,非糖尿病肾病组患者37例)及38例正常对照组的PPARγ2基因Pro12Ala多...     

PPARs信号通路参与肠道菌群和棕色脂肪组织的代谢调控肥胖

背景:肠道菌群与棕色脂肪组织之间存在着复杂的调控机制和广泛联系,但是目前机制尚未阐明。目的:揭示棕色脂肪组织与肠道菌群间的潜在关系,为接下来的研究提供实验思路。方法:由第一作者应用计算机以“brown adipose tissue,intestinal flora,obesity,peroxisome proliferator activated receptor family”为英文检索词,以“棕色脂肪组织,肠道菌群,肥胖,过氧化物酶体增殖物激活受体家族”为中文检索词在PubMed、万方、维普、知网数据库中检索1994-01-01/2020-06-01的相关文献,并对文献的相关内容进一步筛选、归纳分析与总结,最终纳入38篇相关文献进行综述。结果与结论:①肠道菌群失调会影响过氧化物酶体增殖物激活受体(peroxisome proliferator-activated receptors,PPARs),PPARs又可以影响棕色脂肪组织的代谢进而调控肥胖;PPARα、PPARβ和PPARγ都与脂肪代谢有关,可以被相应的激活剂激活促进棕色脂肪组织的表达,其中PPARγ在肠道菌群和棕色脂肪组织中的联系最为密切,肠道菌群代谢的变化可以上调PPARγ的表达,从而激活棕色脂肪组织达到减肥的目的;②调节肠道菌群与棕色脂肪组织的关系可以治疗肥胖症;③从棕色脂肪组织、PPARs信号通路两者中研究抵抗肥胖的相关药物前景可观。     

Liver mitochondrial function and redox status in an experimental model of non-alcoholic fatty liver disease induced by monosodium L-glutamate in rats

The purpose of this work was to determine if mitochondrial dysfunction is involved in the development of non-alcoholic fatty liver disease (NAFLD). Using a model of obesity induced by the neonatal treatment of rats with monosodium l-glutamate (MSG), several parameters of liver mitochondrial function and their impact on liver redox status were evaluated. Specifically, fatty acid β-oxidation, oxidative phosphorylation and Ca²⁺-induced mitochondrial permeability transition were assessed in isolated liver mitochondria, and reduced glutathione (GSH), linked thiol contents and the activities of several enzymes involved in the control of redox status were measured in the liver homogenate. Our results demonstrate that liver mitochondria from MSG-obese rats exhibit a higher β-oxidation capacity and an increased capacity for oxidising succinate, without loss in the efficiency of oxidative phosphorylation. Also, liver mitochondria from obese rats were less susceptible to the permeability transition pore (PTP) opening induced by 1.0 μM CaCl₂. Cellular levels of GSH were unaffected in the livers from the MSG-obese rats, whereas reduced linked thiol contents were increased. The activities of glucose-6-phosphate dehydrogenase, glutathione reductase and glutathione peroxidase were increased, while catalase activity was unaffected and superoxide dismutase activity was reduced in the livers from the MSG-obese rats. In this model of obesity, liver fat accumulation is not a consequence of mitochondrial dysfunction. The enhanced glucose-6-phosphate dehydrogenase activity observed in the livers of MSG-obese rats could be associated with liver fat accumulation and likely plays a central role in the mitochondrial defence against oxidative stress.     

Differential expression of peroxisome proliferator activated receptor γ and cyclin D1 does not affect proliferation of asthma‐ and non‐asthma‐derived airway smooth muscle cells

Background and objective: Airway remodelling involves thickening of the airway smooth muscle (ASM) bulk. Proliferation of asthma‐derived ASM cells is increased in vitro, but underlying mechanisms remain unknown. Peroxisome proliferators activated receptor‐γ (PPARγ) regulates the cell cycle. It is suggested that PPARγ agonists have anti‐inflammatory effects, which may be valuable in the treatment of asthma, but information regarding their antiproliferative properties in ASM is lacking. Although corticosteroids reduce airway inflammation, in vitro they inhibit proliferation in only non‐asthma ASM cells by reducing cyclin D1. We therefore investigated the effects of mitogenic stimulation (foetal bovine serum (FBS)), and a PPARγ ligand (ciglitazone), on PPARγ and cyclin D1 expression and proliferation of ASM cells. In addition, we examined the effects of ciglitazone on ASM cell proliferation. Methods: We assessed PPARγ and cyclin D1 mRNA and protein levels using quantitative PCR and immunoblotting. Cell proliferation was assessed using bromodeoxyuridine uptake. Results: In the presence of 5% FBS, PPARγ and cyclin D1 expression decreased over time in non‐asthmatic cells but increased in asthmatic cells (compared with sub‐confluent cells). FBS‐induced proliferation of asthmatic cells increased at all time points, but occurred only at day 7 with non‐asthmatic cells (compared with unstimulated time‐matched control). Ciglitazone increased PPARγ expression in both groups, but did not alter cell proliferation, while fluticasone increased PPARγ protein only in asthmatic cells. Conclusions: Although in the presence of a mitogenic stimulus, PPARγ was differentially expressed in asthma‐ and non‐asthma‐derived ASM; its expression was not related to the increased proliferation observed in asthmatic ASM.     

Mutation analysis of PEX7 in 60 probands with rhizomelic chondrodysplasia punctata and functional correlations of genotype with phenotype

PEX7 encodes the cytosolic receptor for the set of peroxisomal matrix enzymes targeted to the organelle by the peroxisome targeting signal 2 (PTS2). Mutations in PEX7 cause rhizomelic chondrodysplasia punctata (RCDP), a distinct peroxisome biogenesis disorder. In previous work we described three novel PEX7 mutant alleles, including one, L292X, with a high frequency due to a founder effect. We have now extended our analysis to 60 RCDP probands and identified a total of 24 PEX7 alleles, accounting for 95% of the mutant PEX7 genes in our sample. Of these, 50% are L292X, 13% are IVS9+1G>C, and the remainder are mostly private. IVS9+1G>C occurs on at least three different haplotypes and thus appears to result from recurrent mutation. The phenotypic spectrum of RCDP is broader than commonly recognized and includes minimally affected individuals at the mild end of the spectrum. To relate PEX7 genotype and phenotype, we evaluated the consequence of the disease mutation on PEX7 RNA by Northern analysis and RT/PCR. We evaluated the function of the encoded Pex7 protein (Pex7p) by expressing selected alleles in fibroblasts from RCDP patients and assaying their ability to restore import of a PTS2 marker protein. We find that residual activity of mutant Pex7p and reduced amounts of normal Pex7p are associated with milder and variant phenotypes.     

Preventive effects of siRNA targeting PPARγ gene on steroid-induced osteonecrosis in rabbits

Purposes/Aim: Glucocorticoid steroids can induce expression of PPARγ gene and enhance adipogenesis by bone marrow mesenchymal stem cells (BMSCs), which may result in osteonecrosis of the femoral head. Currently, there are no medications available to prevent steroid-induced osteonecrosis. We hypothesized that siRNA targeting PPARγ gene may prevent steroid-induced adipogenesis and osteonecrosis in rabbit. The purpose of this study was to evaluate the preventive effects of siRNA targeting PPARγ gene on steroid-induced adipogenesis and osteonecrosis.

Methods: Forty-eight healthy New Zealand rabbits were randomized into four groups with Group M treated with dexamethasone only, Group S with dexamethasone and a recombinant adenovirus shuttle vector carrying siRNA targeting PPARγ gene, Group Con with dexamethasone and a vector carrying irrelative sequence, and Group N with no treatment serving as control. Expressions of the PPARγ, osteocalcin and Runx2 genes, as well as histopathologic changes were evaluated.

Results: The levels of PPARγ gene expression were decreased while the levels of osteocalcin and Runx2 gene expression were increased in rabbits treated with dexamethasone and recombinant adenovirus shuttle vector carrying siRNA targeting PPARγ gene (Group S), compared to rabbits treated either with dexamethasone alone (Group M) or with both dexamethasone and a vector carrying irrelative sequence (Group Con). The marrow necrosis, adipocyte hypertrophy and proliferation, diminished hematopoiesis, thinner and sparse trabeculae, and increased empty osteocyte lacunae in the femoral head were observed in Group M and Group Con rabbits. However, no such changes were seen in Group S rabbits that were treated with dexamethasone and a recombinant adenovirus shuttle vector carrying siRNA targeting PPARγ gene.

Conclusion: siRNA targeting PPARγ gene can inhibit adipogenic differentiation of BMSCs and prevent steroid-induced osteonecrosis in rabbit. The inhibition of bone-marrow adipogenesis and concomitant enhancement of osteogenesis with RNAi may provide a novel approach to the prevention of steroid-induced osteonecrosis.     

PPAR-γ配体对绒癌细胞系JEG-3体外增殖、分泌和侵袭能力的影响

目的 观察PPAR-γ配体吡格列酮(PGZ)调节绒癌细胞系JEG-3的增殖、分泌hCG和体外侵袭、转移能力.方法 用MTT法和IEMA测定细胞的增殖和分泌hCG.Matrigel侵袭模型分析细胞的迁徙和侵袭能力.结果 小剂量PGZ对JEG-3有增殖抑制作用,随PGZ浓度的增加,JEG-3透过Matrigel膜的细胞数明显减少(P＜0.01).结论 PGZ明显抑制JEG-3肿瘤细胞的生长和侵袭能力,提示PPAR-γ途径可能是妊娠滋养细胞肿瘤治疗的新方向.     

罗格列酮对急性肺损伤的保护作用

罗格列酮是过氧化物酶体增殖物激活受体-γ特异性配体之一,其调节糖、脂类代谢与稳态,促进细胞增殖、分化的作用已有详尽报道。近年来,罗格列酮在急性肺损伤中发挥的抗炎、抗氧化、保护内皮、减轻肺血管通透性、促进肺成熟以及抗纤维化的作用,日渐受到关注。