A natural PPAR-γ agonist, 15-deoxy-delta 12,14-prostaglandin J2, may act as an enhancer of PAI-1 in human proximal renal tubular cells under hypoxic and inflammatory conditions
A natural PPAR-γ agonist, 15-deoxy-delta 12,14-prostaglandin J2, may act as an enhancer of PAI-1 in human proximal renal tubular cells under hypoxic and inflammatory conditions
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DOI：
10.1093/ndt/gfn139
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发表时间：
2008-08-01
影响因子：
6.1
通讯作者：
Yoshida, Haruyoshi
中科院分区：
文献类型：
--
作者：
Kimura, Hideki;Li, Xuan;Yoshida, Haruyoshi
背景据报道，缺氧和炎症是肾纤维化发展过程中肾小管细胞不可避免的环境，其上调纤溶酶原激活物抑制剂-1（PAI-1）的产生，PAI-1是组织纤维化的促进剂。过氧化物酶体增殖物激活受体（PPAR-gamma）激动剂可能通过其抗炎作用以PPAR-gamma依赖性或非依赖性方式调节肾纤维化进展。然而，没有关于PPAR-gamma激动剂对缺氧和/或炎症下人近端肾小管细胞（HPTEC）中派-1表达的影响的信息。将汇合的HPTEC暴露于常氧（18% O（2））、缺氧（1% O（2））和/或10 ng/mL的TNF-α中长达48 h。将细胞与两种PPAR-γ前体15-脱氧-δ 12，14-前列腺素J2（15 d-PGJ 2）和吡格列酮孵育。分别用TaqMan定量PCR和免疫分析法测定派-1 mRNA和蛋白的精确量。用PPRE-荧光素酶构建体转染细胞，检测15 d-PGJ 2诱导的PPRE活性。基础派-1显着增加，以剂量依赖性的方式，由15天PGJ 2。在mRNA和蛋白水平上，它还增强了缺氧、TNF-α和缺氧加TNF-α刺激的派-1表达。吡格列酮对派-1蛋白的产生无影响。尽管15 d-PGJ 2在表达PPAR-gamma的HPTEC中显著增强PPRE活性，但PPAR-gamma的特异性抑制剂GW 9662并不减少15 d-PGJ 2诱导的派-1表达。而非选择性酪氨酸激酶（TK）抑制剂genisteine或MAPK激酶（MEK 1）抑制剂PD 98059则完全抑制15 d-PGJ 2诱导的派-1的产生。内源性PPAR-gamma激动剂15 d-PGJ 2通过激活HPTEC中的TK或MAP激酶而独立于PPAR-gamma增加派-1表达，并且可以在缺氧和炎症条件下作为肾脏中派-1产生的增强剂。
Background. Hypoxia and inflammation, an unavoidable milieu for renal tubular cells during the development of renal fibrosis, reportedly up-regulate production of plasminogen activator inhibitor-1 (PAI-1), a promoter of tissue fibrosis. Peroxisome proliferator-activated receptor (PPAR)-gamma agonists may modulate renal fibrosis progression via their anti-inflammatory effects in a PPAR-gamma-dependent or -independent manner. However, no information is known about the effects of PPAR-gamma agonists on PAI-1 expression in human proximal renal tubular cells (HPTECs) under hypoxia and/or inflammation.Methods. Confluent HPTECs were exposed to normoxia (18% O(2)), hypoxia (1% O(2)) and/or TNF-alpha at 10 ng/mL for up to 48 h. The cells were incubated with two PPAR-gamma ago- nists, 15-deoxy-delta 12,14-prostaglandin J2 (15d-PGJ2) and pioglitazone. Precise amounts of PAI-1 mRNA and protein were measured by TaqMan quantitative PCR and immunoassay, respectively. PPAR response element (PPRE) activity induced by 15d-PGJ2 was measured by transfection with PPRE-luciferase construct.Results. Basal PAI-1 was significantly increased, in a dose-dependent manner, by 15d-PGJ2. It also enhanced hypoxia-, TNF-alpha- and hypoxia plus TNF-alpha-stimulated PAI-1 expression at the mRNA and protein levels. Pioglitazone had no influence on PAI-1 protein production. Although 15d-PGJ2 enhanced PPRE activity significantly in the HPTECs expressing PPAR-gamma, a specific inhibitor for PPAR-gamma, GW9662, did not diminish 15d-PGJ2-induced PAI-1 expression. In contrast, a non-selective tyrosine kinase (TK) inhibitor, genisteine or a MEK1 (MAPK kinase) inhibitor, PD98059, inhibited 15d-PGJ2-induced PAI-1 production completely.Conclusions. The endogenous PPAR-gamma agonist, 15d-PGJ2, increased PAI-1 expression independently of PPAR-gamma via the activation of TK or MAP kinase in HPTECs and may act as an enhancer of PAI-1 production in the kidney under hypoxic and inflammatory conditions.