Protective factors in diabetic kidney disease in patients with type 1 diabetes

科学摘要：糖尿病肾病(DKD)是导致终末期肾病的主要原因。而DKD 伤害因素得到了广泛的研究，保护因素的定义仍然很模糊，并呈现出关键的知识 差距。最近，我们和其他人描述了DKD中潜在的保护和修复机制的存在。 这些概念值得进一步研究，有可能极大地改善结果。论文来源： 我们和其他实验室证实，经过多次传代后，培养的皮肤成纤维细胞(SF)的行为不同 DKD患者与非DKD患者之间的差异。与保护机制一致，我们早期的基因 表达研究表明，受到DKD保护的个体有一些不同于 DKD患者和正常对照组，表明保护组有独特的细胞行为 与DKD皮损发展非常缓慢有关。我们最新的基因表达研究(hi-seq)在SF生长 在高糖(HG)中发现了与DNA复制和修复、蛋白质修复和细胞周期相关途径 在无DKD的1型糖尿病患者(T1D)中，与T1D患者相比，它们显著过度表达 与DKD和非糖尿病对照组比较。这些途径在同卵双胞胎的SF中也有不同的表达 与T1D不协调。因此，在表观遗传学上，这些通路的上调被认为是对DKD的保护 受监管的。高血糖导致DNA损伤，从而激活DNA修复途径[主要是碱基 切除修复(BER)途径]，以恢复DNA完整性和防止细胞功能障碍。事实上， 无DKD的T1D患者BER通路显著上调(p=5.14e-5) DKD和控件。我们的初步数据表明，BER通路在近端肾小管中也有上调 上皮细胞(PTEC)。我们将测试这些途径的差异是否与功能差异有关 从T1D志愿者的研究皮肤和肾脏活检组织中培养的SF和PTEC。我们的具体目标是 确定1)体外HG对SF中BER蛋白水平、DNA损伤和修复能力的影响 以及它们与DKD风险的关系，2)BER蛋白水平、DNA损伤、修复能力和反应的变化 HG培养的PTEC中的一种治疗药物及其与DKD风险的关系，3)尿DNA损伤水平 与DKD风险相关的产品，以及4)与关键基因表达相关的表观遗传机制 差异表达的误码率途径基因。我们假设，尽管患有和不患有T1D的患者 与对照组相比，DKD可能增加了BER通路的活性，这种活性在 我们的强健的SF发现将在PTEC中总结。鉴于...的深度 我们在相关领域的基础科学强项、独特的研究材料、创新的技术 凭借我们精湛的调查团队的能力，以及我们成熟的合作轨迹，我们处于非常有利的地位 为了顺利完成这些研究。如果我们的假设得到证实，这项工作将开启新的研究 旨在预防DKD的途径。

Scientific Abstract: Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease. While DKD injury factors are extensively studied, protective factors remain poorly defined and present a critical knowledge gap. Recently we and others described the existence of potential protective and healing mechanisms in DKD. These concepts warrant further investigation and have the potential to greatly improve outcomes. Papers from our and other laboratories confirm that after multiple passages cultured skin fibroblasts (SF) behaviors differ between patients with versus without DKD. Consistent with protective mechanisms, our earlier gene expression studies showed that individuals protected from DKD had some SF behaviors that differ both from patients with DKD and from normal controls, suggesting the protected group had unique cellular behaviors associated with very slow development of DKD lesions. Our recent gene expression studies (hi-seq) in SF grown in high glucose (HG) uncovered that pathways related to DNA replication and repair, protein repair, and cell cycle were markedly overexpressed in patients with type 1 diabetes (T1D) without DKD as compared to T1D patients with DKD and non-diabetic controls. These pathways were also differently expressed in SF of monozygotic twins discordant for T1D. Thus, upregulation of these pathways is posited as protective of DKD and epigenetically regulated. Hyperglycemia induces DNA damage, thus activating DNA repair pathways [primarily the base excision repair (BER) pathway] in order to restore DNA integrity and prevent cellular dysfunction. Indeed, the BER pathway was markedly up-regulated in T1D patients without DKD (p=5.14e-5) as compared to patients with DKD and controls. Our preliminary data indicate that BER pathway is also upregulated in proximal tubular epithelial cells (PTEC). We will test whether these pathway differences are associated with functional differences in SF and PTEC cultured from research skin and kidney biopsies in T1D volunteers. Our Specific Aims are to determine 1) changes in BER protein levels, DNA damage and repair capacity in SF in response to in vitro HG and their relationship to DKD risk, 2) changes in BER protein levels, DNA damage, repair capacity and response to a therapeutic agent in PTEC cultured in HG and their relationship to DKD risk, 3) urinary levels of DNA damage products in relation to DKD risk, and 4) epigenetic mechanisms associated with gene expression in key differentially expressed BER pathway genes. We hypothesize that, although both T1D patients with and without DKD may have increased BER pathway activity compared to controls, this activity will be much greater in the patients protected from DKD, and that our robust SF findings will be recapitulated in PTEC. Given the depth of our basic science strengths in the relevant areas, the unique research materials, the innovative technical capabilities of our superb investigative team, and our proven collaboration track, we are extremely well positioned for the successful completion of these studies. If our hypotheses are borne out, this work will open new research avenues aimed at DKD prevention.