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

糖尿病肾病（DKD）是终末期肾病的主要原因。当DKD 损伤因素被广泛研究，保护因素仍然定义不清，目前的关键知识 间隙最近，我们和其他人描述了DKD中潜在的保护和愈合机制的存在。 这些概念值得进一步研究，并有可能大大改善结果。论文 我们和其他实验室证实，经过多次传代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，我们的早期基因 表达研究表明，受保护的DKD个体具有一些SF行为，这些行为既不同于 DKD患者和正常对照组的细胞凋亡，提示保护组具有独特的细胞行为 与DKD病变发展非常缓慢相关。我们最近的基因表达研究（hi-seq）在SF生长 在高葡萄糖（HG）中揭示了与DNA复制和修复、蛋白质修复以及细胞周期相关通路 与1型糖尿病患者相比，1型糖尿病（T1 D）患者（无DKD）中 DKD和非糖尿病对照组。这些通路在同卵双生子的SF中也有不同的表达 T1 D不一致。因此，这些途径的上调被认为是DKD和表观遗传学的保护性途径。 监管.高血压诱导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完整性并防止细胞功能障碍。持续增 BER通路在无DKD的T1 D患者中显著上调（p=5.14e-5）， DKD和对照。我们的初步数据表明，BER途径也在近端肾小管上皮细胞中上调， 上皮细胞（PTEC）。我们将测试这些通路差异是否与功能差异有关 在从T1 D志愿者的研究皮肤和肾活检中培养的SF和PTEC中。我们的具体目标是 确定1）响应于体外HG的SF中BER蛋白水平、DNA损伤和修复能力的变化 及其与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 在HG中培养的PTEC中的治疗剂及其与DKD风险的关系，3）尿DNA损伤水平 与DKD风险相关的表观遗传机制，以及4）与DKD关键基因表达相关的表观遗传机制。 差异表达的BER通路基因。我们假设，尽管T1 D患者有和没有 与对照相比，DKD可能具有增加的BER途径活性，该活性在DKD中将大得多。 患者免受DKD的影响，并且我们稳健的SF结果将在PTEC中重现。考虑到 我们在相关领域的基础科学优势，独特的研究材料，创新的技术 凭借我们出色的调查团队的能力以及经过验证的合作轨迹，我们处于非常有利的地位 成功完成这些研究。如果我们的假设得到证实，这项工作将开启新的研究领域。 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.