Response of HK-2 cells to STAT3 activation by interleukin-6 and inhibition with S3I-201. Homo sapiens

Abstract: Human kidney function declines with age, accompanied by stereotyped changes in gene expression and histopathology, but the mechanisms underlying these changes are largely unknown. We compared age-associated changes in global gene expression patterns in the human kidney with genome-wide maps of transcription factor occupancy in human cell lines to identify potential regulators of gene expression changes in the aging kidney. The strongest associations involved three inflammation-associated transcription factors: NFκB, STAT1 and STAT3. We found that the activity of these transcription factors increases with age in epithelial compartments of the renal cortex. Stimulation of renal tubular epithelial cells with the inflammatory cytokines IL-6 (a STAT3 activator), IFN-γ (a STAT1 activator), or TNFα (an NFκB activator) recapitulated age-associated gene expression changes. We found that common DNA variants in the two genes that encode the subunits of the canonical NFκB transcription factor (RELA and NFKB1) showed significant associations with kidney function and chronic kidney disease in gene association studies, providing the first evidence for a direct link between genetic variation in NFκB and individual differences in age-related phenotypes in the kidney. Our results point to chronic inflammation, mediated by NFκB, STAT1 and STAT3, as a dominant mechanism influencing gene expression changes during kidney aging. Overall design: Duplicate or triplicate experiments (biological replicates) were performed for each condition

摘要：人类肾功能随年龄增长逐渐衰退，同时伴随基因表达与组织病理学的特征性改变，但此类改变背后的分子机制在很大程度上仍未明确。本研究将人类肾脏中与年龄相关的全局基因表达模式变化，与人类细胞系中转录因子结合的全基因组图谱进行比对，以鉴定衰老肾脏中基因表达改变的潜在调控因子。最强关联涉及三种炎症相关转录因子：核因子κB（NFκB）、信号转导与转录激活因子1（STAT1）及信号转导与转录激活因子3（STAT3）。我们发现，在肾皮质上皮区域中，这些转录因子的活性随年龄增长而升高。使用炎性细胞因子白细胞介素6（IL-6，STAT3激活剂）、干扰素γ（IFN-γ，STAT1激活剂）或肿瘤坏死因子α（TNFα，NFκB激活剂）刺激肾小管上皮细胞，可重现与年龄相关的基因表达改变。在基因关联研究中，我们发现编码经典NFκB转录因子亚基的两个基因（RELA与NFKB1）的常见DNA变异与肾功能及慢性肾脏病存在显著关联，这首次为NFκB的遗传变异与肾脏年龄相关表型的个体差异之间的直接关联提供了证据。本研究结果表明，由NFκB、STAT1及STAT3介导的慢性炎症是影响肾脏衰老过程中基因表达改变的核心机制。整体实验设计：针对每一种实验条件，均开展重复或三次重复实验（生物学重复）。