Perri Anna, Vizza Donatella, Lupinacci Simona, Toteda Giuseppina, De Amicis Francesca, Leone Francesca, Gigliotti Paolo, Lofaro Danilo, La Russa Antonella, Bonofiglio Renzo
"Kidney and Transplantation"Research Center, Department of Nephrology Dialysis and Transplantation, Annunziata Hospital, via F. Migliori 1, 87100, Cosenza, Italy.
Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, CS, Italy.
J Nephrol. 2016 Apr;29(2):185-194. doi: 10.1007/s40620-015-0220-2. Epub 2015 Jul 28.
The pathogenetic role of adiponectin (ADPN) in kidney failure is not yet elucidated, since in vitro and in vivo studies have demonstrated that ADPN exerts both anti-inflammatory and pro-inflammatory effects. Starting from our previous findings demonstrating that HK-2 cells express and secrete ADPN, in this study we investigated the autocrine role of ADPN in tubular inflammatory damage induced by lipopolysaccharide (LPS) and the underlying molecular mechanisms. Firstly, we observed that short-term exposure to LPS enhanced ADPN protein expression as well as the adiponectin receptor ADIPOR1 mRNA content together with its signaling pathway downstream, pAMPK/pERK/pJNK, whose up-regulation status was reversed when ADPN gene knockdown occurred. Interestingly, in the same experimental conditions, we observed that ADPN mediated the nuclear translocation of the transcription factors nuclear factor kappa B (NFkB) and pcFos/pcJun (activator protein 1, AP-1), both induced by the pJNK pathway and involved in tumor necrosis factor (TNF)-α transactivation. Indeed, by transient transfection assay, we observed that the LPS-induced increase of TNF-α promoter activity was abrogated in cells pretreated with the inhibitors of NFkB and AP-1. Collectively our results suggest that in HK-2 cells, ADPN produced upon LPS stimulus could worsen the inflammatory damage in an autocrine-dependent manner.
脂联素（ADPN）在肾衰竭中的致病作用尚未阐明，因为体外和体内研究表明，ADPN兼具抗炎和促炎作用。基于我们之前的研究发现HK-2细胞能够表达并分泌ADPN，在本研究中，我们调查了ADPN在脂多糖（LPS）诱导的肾小管炎性损伤中的自分泌作用及其潜在分子机制。首先，我们观察到短期暴露于LPS会增强ADPN蛋白表达以及脂联素受体ADIPOR1的mRNA含量及其下游信号通路pAMPK/pERK/pJNK，当ADPN基因敲低时，其上调状态会逆转。有趣的是，在相同的实验条件下，我们观察到ADPN介导了转录因子核因子κB（NFkB）和pcFos/pcJun（激活蛋白1，AP-1）的核转位，二者均由pJNK途径诱导并参与肿瘤坏死因子（TNF）-α的反式激活。实际上，通过瞬时转染实验，我们观察到在用NFkB和AP-1抑制剂预处理的细胞中，LPS诱导的TNF-α启动子活性增加被消除。我们的研究结果共同表明，在HK-2细胞中，LPS刺激产生的ADPN可能以自分泌依赖的方式加重炎性损伤。
