Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University SOM, 48201, Detroit, MI, USA.
Inflamm Res. 2018 Dec;67(11-12):1013-1019. doi: 10.1007/s00011-018-1196-x. Epub 2018 Oct 17.
Inflammation is a key component of a number of diseases, including diabetic retinopathy. We investigated the cellular pathway by which protein kinase A (PKA) inhibited high mobility group box 1 (HMGB1).
Primary human retinal endothelial cells (REC) were grown in normal glucose (5 mM) or high glucose (25 mM). Cells in high glucose were treated with exchange protein for cAMP 1 (Epac1) and IGFBP-3 siRNA. Additional cells in high glucose were treated with forskolin, a PKA agonist, and Epac1 siRNA. Some cells were treated with a plasmid for insulin-like growth factor binding protein 3 (IGFBP-3) that does not bind IGF-1. Finally, some REC received Ex527, a sirtuin 1 (SIRT1) antagonist, prior to forskolin treatment. Protein analyses were done for HMGB1, Epac1, IGFBP-3, SIRT1, and PKA.
PKA inhibited cytoplasmic HMGB1, independent of Epac1 actions. PKA activated IGFBP-3 and SIRT1 to inhibit cytoplasmic HMGB1. High glucose inhibited SIRT1 levels and increased cytoplasmic HMGB1 in REC.
PKA requires active IGFBP-3 and SIRT1 to inhibit HMGB1 inflammatory actions in the retina vasculature. Activation of these pathways may offer new targets for therapy development.
炎症是包括糖尿病视网膜病变在内的多种疾病的关键组成部分。我们研究了蛋白激酶 A（PKA）抑制高迁移率族蛋白 B1（HMGB1）的细胞途径。
培养原代人视网膜内皮细胞（REC）于正常葡萄糖（5 mM）或高葡萄糖（25 mM）中。高葡萄糖中的细胞用交换蛋白 for cAMP 1（Epac1）和 IGFBP-3 siRNA 处理。高葡萄糖中的其他细胞用 PKA 激动剂 forskolin和 Epac1 siRNA 处理。一些细胞用不结合 IGF-1 的胰岛素样生长因子结合蛋白 3（IGFBP-3）质粒处理。最后，一些 REC 在接受 forskolin 处理之前，先用 sirtuin 1（SIRT1）拮抗剂 Ex527 处理。对 HMGB1、Epac1、IGFBP-3、SIRT1 和 PKA 进行蛋白分析。
PKA 抑制细胞质 HMGB1，独立于 Epac1 作用。PKA 激活 IGFBP-3 和 SIRT1 以抑制细胞质 HMGB1。高葡萄糖抑制 REC 中的 SIRT1 水平并增加细胞质 HMGB1。
PKA 需要活性 IGFBP-3 和 SIRT1 来抑制视网膜血管中的 HMGB1 炎症作用。这些途径的激活可能为治疗开发提供新的靶点。
