Sucajtys-Szulc Elzbieta, Szolkiewicz Marek, Swierczynski Julian, Rutkowski Boleslaw
Department of Nephrology, Transplantology and Internal Medicine, Medical University of Gdansk, Poland.
Department of Biochemistry, Medical University of Gdansk, Poland.
Atherosclerosis. 2016 May;248:17-26. doi: 10.1016/j.atherosclerosis.2016.02.027. Epub 2016 Feb 27.
The aim of this study was to verify if an increase in Hnf1α gene expression could be a possible link between circulating proprotein convertase subtilisin/kexin type 9 (PCSK9) and TAGs concentrations in chronic renal failure (CRF).
Rats underwent 5/6 nephrectomy or a sham surgery. Liver expressions of Pcsk9, Mttp, ApoB-100, Hnf1α, Hnf4α, lipogenic enzymes and β-actin genes were quantified by qPCR. Liver levels of proteins coding by these genes were analyzed by Western blotting. Serum apoB-100 and PCSK9 concentration were estimated with an immunoassay.
CRF rats showed an increase in circulating concentrations of TAGs, VLDL, apoB-100 and PCSK9, along with an enhanced liver VLDL-TAG secretion rate and a coordinated liver up-regulation of genes coding: a) lipogenic enzymes; b) Mttp and ApoB-100; c) Pcsk9; d) Hnf1α and Hnf4α. Positive correlations were found between serum creatinine concentrations and: a) the liver levels of HNF1α mRNA (r = 0.79, p < 0.01) and HNF4α (r = 0.76, p < 0.01); b) the liver levels of PCSK9 mRNA (r = 0.88, p < 0.01) and serum PCSK9 concentrations (r = 0.73, p < 0.01); c) the liver levels of apoB-100 mRNA (r = 0.83, p < 0.01) and serum apoB-100 concentrations (r = 0.87, p < 0.01). Clofibrate treatment was shown to concomitantly decrease the liver levels of HNF1α, HNF4α and PCSK9 mRNA, as well as serum PCSK9, TAGs and total cholesterol concentrations in CRF rats.
The results presented are consistent with a cause-effect relationship between the enhanced liver expression of Hnf1α gene and its target genes the products of which are involved in synthesis, assembly and secretion of VLDL, as well as Pcsk9 gene in CRF rats. This may at least in part explain an association between circulating PCSK9 and TAGs in CRF rats and possibly also in humans with chronic kidney disease (CKD).
本研究的目的是验证肝细胞核因子1α（Hnf1α）基因表达的增加是否可能是慢性肾衰竭（CRF）患者循环中前蛋白转化酶枯草溶菌素/九型（PCSK9）与甘油三酯（TAGs）浓度之间的潜在联系。
对大鼠进行5/6肾切除术或假手术。通过定量聚合酶链反应（qPCR）定量肝脏中Pcsk9、微粒体甘油三酯转运蛋白（Mttp）、载脂蛋白B-100（ApoB-100）、Hnf1α、Hnf4α、脂肪生成酶和β-肌动蛋白基因的表达。通过蛋白质免疫印迹法分析这些基因编码的蛋白质的肝脏水平。用免疫测定法估计血清载脂蛋白B-100和PCSK9浓度。
CRF大鼠的TAGs、极低密度脂蛋白（VLDL）、载脂蛋白B-100和PCSK9的循环浓度增加，同时肝脏VLDL-TAG分泌率提高，并且肝脏中编码以下物质的基因协调上调：a）脂肪生成酶；b）Mttp和载脂蛋白B-100；c）Pcsk9；d）Hnf1α和Hnf4α。血清肌酐浓度与以下各项之间存在正相关：a）肝脏中HNF1α mRNA水平（r = 0.79，p < 0.01）和HNF4α水平（r = 0.76，p < 0.01）；b）肝脏中PCSK9 mRNA水平（r = 0.88，p < 0.01）和血清PCSK9浓度（r = 0.73，p < 0.01）；c）肝脏中载脂蛋白B-100 mRNA水平（r = 0.83，p < 0.01）和血清载脂蛋白B-100浓度（r = 0.87，p < 0.01）。氯贝丁酯治疗显示可同时降低CRF大鼠肝脏中HNF1α、HNF4α和PCSK9 mRNA水平，以及血清PCSK9、TAGs和总胆固醇浓度。
所呈现的结果与CRF大鼠肝脏中Hnf1α基因及其靶基因（其产物参与VLDL的合成、组装和分泌）以及Pcsk9基因表达增强之间的因果关系一致。这可能至少部分解释了CRF大鼠以及可能患有慢性肾脏病（CKD）的人类中循环PCSK9与TAGs之间的关联。
