AGEs-RAGE-K Ca 3.1 pathway mediates palmitic acid-induced migration of PBMCs from patients with type 2 diabetes.

Type 2 diabetes mellitus (T2DM) is characterized by chronic low-grade systemic inflammation. Tissue infiltration by monocyte migration contributes to the pathogenesis of vascular complications in T2DM. We studied the role of intermediate-conductance Ca ²⁺ -activated K ⁺ (K _Ca 3.1) channels in the palmitic acid (PA)-induced migration of peripheral blood mononuclear cells (PBMCs) from T2DM patients and the influence of advanced glycation endproducts (AGEs). A total of 49 T2DM patients and 33 healthy subjects was recruited into this study. Using flow cytometry and Western blotting analysis as well as cell migration assay, we found that there was a significant decrease in frequency of T lymphocytes and monocytes in CD45 ⁺ leukocyte population. PA at 100 μM stimulated migration of PBMCs from T2DM individuals, which was inhibited by the specific K _Ca 3.1 channel blocker TRAM-34 (1 μM). The PBMC migration was positively correlated with glycosylated hemoglobin A1 chain (HbA1c) level of T2DM patients, an indicator of AGEs, and PBMCs with higher level of HbA1c showed upregulated expression of toll-like receptor (TLR) 2/4 and K _Ca 3.1 channels. In THP-1 cells, AGEs at 200 μg/ml increased protein expression of TLR 2/4 and K _Ca 3.1 channels, and were synergistically involved in PA-induced migration through receptors of AGEs (RAGE)-mediated K _Ca 3.1 upregulation. In conclusion, in PBMCs of T2DM patients, AGEs promotes PA-induced migration via upregulation of TLR2/4 and K _Ca 3.1 channels.
Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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