Table_6_PRDX6: A protein bridging S-palmitoylation and diabetic neuropathy.xlsx

Diabetic neuropathy is regarded as one of the most debilitating outcomes of diabetes. It can affect both the peripheral and central nervous systems, leading to pain, decreased motility, cognitive decline, and dementia. S-palmitoylation is a reversible posttranslational lipid modification, and its dysregulation has been implicated in metabolic syndrome, cancers, neurological disorders, and infections. However, the role of S-palmitoylation in diabetic neuropathy remains unclear. Here we demonstrate a potential association between activating protein palmitoylation and diabetic neuropathy. We compared the proteomic data of lumbar dorsal root ganglia (DRG) of diabetes mice and palmitoylome profiling data of the HUVEC cell line. The mapping results identified peroxiredoxin-6 (PRDX6) as a novel target in diabetic neuropathy, whose biological mechanism was associated with S-palmitoylation. Bioinformatic prediction revealed that PRDX6 had two palmitoylation sites, Cys47 and Cys91. Immunofluorescence results indicated PRDX6 translocating between the cytoplasm and cell membrane. Protein function analysis proposed that increased palmitoylation could competitively inhibit the formation of disulfide-bond between Cys47 and Cys91 and change the spatial topology of PRDX6 protein. Cl–HCO3- anion exchanger 3 (AE3) was one of the AE family members, which was proved to express in DRG. AE3 activity evoked Cl- influx in neurons which was generally associated with increased excitability and susceptibility to pain. We demonstrated that the S-palmitoylation status of Cys47 could affect the interaction between PRDX6 and the C-terminal domain of AE3, thereby regulating the activity of AE3 anion exchanger enzyme in the nervous system. The results highlight a central role for PRDX6 palmitoylation in protection against diabetic neuropathy.

糖尿病神经病变（Diabetic neuropathy）被视为糖尿病最具致残性的并发症之一。它可累及外周与中枢神经系统，引发疼痛、运动功能减退、认知能力下降及痴呆。S-棕榈酰化（S-palmitoylation）是一种可逆的翻译后脂质修饰，其失调与代谢综合征、癌症、神经系统疾病及感染的发生发展密切相关。然而，S-棕榈酰化在糖尿病神经病变中的作用仍未明确。本研究揭示了蛋白质棕榈酰化激活与糖尿病神经病变之间的潜在关联。我们对比了糖尿病小鼠腰背根神经节（lumbar dorsal root ganglia, DRG）的蛋白质组学数据与人类脐静脉内皮细胞系（HUVEC cell line）的棕榈酰化组谱数据，经数据映射分析后，鉴定出过氧化物酶6（PRDX6）为糖尿病神经病变的新型靶点，其生物学机制与S-棕榈酰化相关。生物信息学预测显示，PRDX6存在两个棕榈酰化位点：Cys47与Cys91。免疫荧光实验结果表明，PRDX6可在细胞质与细胞膜之间发生转位。蛋白质功能分析提示，增强的棕榈酰化可竞争性抑制Cys47与Cys91之间二硫键的形成，并改变PRDX6蛋白的空间拓扑结构。Cl–HCO3-阴离子交换蛋白3（AE3）属于阴离子交换蛋白（AE）家族成员，已被证实表达于背根神经节中。AE3的激活可介导神经元内Cl-内流，这一过程通常与神经元兴奋性升高及痛觉易感性增加相关。本研究证实，Cys47的S-棕榈酰化状态可影响PRDX6与AE3 C端结构域的相互作用，从而调控神经系统中AE3阴离子交换酶的活性。本研究结果凸显了PRDX6棕榈酰化在对抗糖尿病神经病变中的核心保护作用。