Aims

Lactate accumulation is reported to be a biomarker for diabetic nephropathy progression. Lactate drives lysine lactylation, a newly discovered post-translational modification that is involved in the pathogenesis of cancers and metabolic and inflammatory disease. Here, we aimed to determine whether lysine lactylation is involved in the pathogenesis of diabetic nephropathy.

Methods

Renal biopsy samples from individuals with diabetic nephropathy (n=22) and control samples from individuals without diabetes and kidney disease (n=9) were obtained from the First Affiliated Hospital of Zhengzhou University for immunohistochemical staining. In addition, we carried out global lactylome profiling of kidney tissues from db/m and db/db mice using LC-MS/MS. Furthermore, we assessed the role of lysine lactylation and acyl-CoA synthetase family member 2 (ACSF2) in mitochondrial function in human proximal tubular epithelial cells (HK-2).

Results

The expression level of lysine lactylation was significantly increased in the kidneys of individuals with diabetes as well as in kidneys from db/db mice. Integrative lactylome analysis of the kidneys of db/db and db/m mice identified 165 upregulated proteins and 17 downregulated proteins, with an increase in 356 lysine lactylation sites and a decrease in 22 lysine lactylation sites decreased. Subcellular localisation analysis revealed that most lactylated proteins were found in the mitochondria (115 proteins, 269 sites). We further found that lactylation of the K182 site in ACSF2 contributes to mitochondrial dysfunction. Finally, the expression of ACSF2 was notably increased in the kidneys of db/db mice and individuals with diabetic nephropathy.

Conclusions

Our study strongly suggests that lysine lactylation and ACSF2 are mediators of mitochondrial dysfunction and may contribute to the progression of diabetic nephropathy.

Data availability

The LC-MS/MS proteomics data have been deposited in the ProteomeXchange Consortium database (https://proteomecentral.proteomexchange.org) via the iProX partner repository with the dataset identifier PXD050070.

Graphical Abstract

中文翻译：

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ACSF2 和赖氨酸乳酰化导致糖尿病肾小管损伤

目标

据报道，乳酸积累是糖尿病肾病进展的生物标志物。乳酸驱动赖氨酸乳酰化，这是一种新发现的翻译后修饰，参与癌症以及代谢和炎症疾病的发病机制。在这里，我们的目的是确定赖氨酸乳酰化是否参与糖尿病肾病的发病机制。

方法

糖尿病肾病患者的肾活检样本（n = 22）和非糖尿病肾病患者的对照样本（n = 9）取自郑州大学第一附属医院，进行免疫组织化学染色。此外，我们使用 LC-MS/MS对db/m和db/db小鼠的肾组织进行了整体乳糖组分析。此外，我们评估了赖氨酸乳酰化和酰基辅酶A合成酶家族成员2 (ACSF2)在人近端肾小管上皮细胞(HK-2)线粒体功能中的作用。

结果

糖尿病个体的肾脏以及db/db小鼠的肾脏中赖氨酸乳酰化的表达水平显着增加。对db/db和db/m小鼠肾脏的综合乳糖组分析发现 165 个上调蛋白和 17 个下调蛋白，其中 356 个赖氨酸乳酰化位点增加，22 个赖氨酸乳酰化位点减少。亚细胞定位分析显示，大多数乳酰化蛋白存在于线粒体中（115 个蛋白，269 个位点）。我们进一步发现 ACSF2 中 K182 位点的乳酰化会导致线粒体功能障碍。最后，ACSF2 的表达在db/db小鼠和糖尿病肾病个体的肾脏中显着增加。

结论

我们的研究强烈表明赖氨酸乳酰化和 ACSF2 是线粒体功能障碍的介质，可能导致糖尿病肾病的进展。

数据可用性

LC-MS/MS 蛋白质组数据已通过 iProX 合作伙伴存储库存储在 ProteomeXchange 联盟数据库 (https://proteomecentral.proteomexchange.org) 中，数据集标识符为 PXD050070。

图形概要