NEDD4L基因多态性对IgA肾病患者动态血压的影响及机制研究

Hypertension and abnormal circadian rhythm of BP increased the cardiovascular events incidence and mortality rate. It has been reported ENaC regulatory protein -NEDD4L genetic variation affected urinary sodium excretion and was associated with hypertension. Whether NEDD4L genetic variation affected blood pressure in patients with IgA nephropathy has not been reported yet. Our preliminary experiments found NEDD4L rs4149601 AA genotype carriers had a higher blood pressure, higher incidence of hypertension and no dipper blood pressuer than GG/GA carriers in IgAN patients. This study would firstly screen SNPs by re-sequencing exon, intron-exon boundaries of NEDD4L gene in part of IgAN patients, then construct haplotype and select tagSNP by HAPLOVIEW software. tagSNPs were genotyped by realtime PCR using TaqMan assays in large scale IgAN patients. Collect clinic data of met the inclusion criteria of IgAN patients and measured ambulatory blood pressure and urinary sodium excretion during the day and night. Immunofluorescence detected the expression of ENac protein in Tubular epithelial cells. Analysis the incidence of no dipper blood pressuer and hypertension, the level of blood pressuer, urinary sodium excretion and expression of ENaC in different genotype in IgAN patients. Analysis the effect of NDEE4L gene variation on blood pressure and mechanism.

高血压及血压的昼夜节律异常增加了CKD患者的心血管事件发生率及死亡率。既往研究发现ENaC调节蛋白-NEDD4L基因变异影响尿钠排泄率且与高血压密切相关。NEED4L基因变异对IgA肾病患者血压影响未见报道，我们前期实验发现IgAN患者NEDD4L基因rs4149601 AA型携带者血压水平、非杓型血压及高血压发生率均高于GG/GA型携带者。本研拟进一步在IgAN患者中对该基因内含子、外显子及其交界区进行SNP筛查，haploveiw软件构建单倍型域，选择标签SNP；大样本对标签SNP进行基因分型，同时对所有IgAN患者进行动态血压监测及测定白天及夜间尿钠排泄率，免疫荧光检测患者肾小管上皮细胞ENaC的表达水平。分析不同基因型IgAN患者的血压水平，非杓型血压及高血压的发生率及尿钠排泄率及肾小管上皮细胞ENaC的表达。阐明NEDD4L基因变异对IgAN患者动态血压的影响及其发生机理。

项目背景：高血压及血压的昼夜节律异常增加了CKD患者的心血管事件发生率及死亡率。既往研究发现钠通道蛋白(ENaC)的调节蛋白-NEDD4L基因变异与高血压及血压模式密切相关。NEED4L基因变异对CKD患者动态血压的影响未见报道，主要研究内容：我们通过收集符合入组标准的CKD病例，对其进行动态血压监测，获得患者动态血压及血压模式的数据；收集患者的血液标本并提取DNA建立长期用于研究的标本库；收集患者临床资料、病理资料，检测患者白天及夜间尿钠排泄率，每个患者动态血压完成后填写当天睡眠日记，评估患者的睡眠质量；对候选基因rs4149601及rs2288774 SNPs进行基因分型，获得所有CKD患者的SNPs数据。分析CKD患者各SNPs不同基因型对动态血压、血压模式的影响，结果：对于rs4149601基因多态位点，510例CKD患者属于GA/GG基因型，24例患者携带AA基因型，AA基因型携带者比GA/GG基因型携带者具有更高的高血压发生率（73.3% vs 46.8%， P<0.05），AA型携带者比GA/GG基因型具有更高的收缩压及舒张压水平（137±15 vs 128±17, P<0.05；82±11 vs 78±10，P<0.05），多因素逻辑回归分析发现rs4149601 AA基因型为非杓型血压(HR：2.45，CI:1.02-8.24，P<0.05)及高血压(HR：6.41，CI:1.01-18.24，P<0.05)独立的危险因素。rs2288774基因型分别为CC基因型87例、CT基因型255例、TT基因型201例，各基因型与血压水平、高血压及血压模式无显著相关(P＞0.05)。结论：NEDD4L基因rs4149601多态性与CKD患者高血压及血压模式相关，应进一步对该基因对血压影响机制进行研究。