Binuclear ruthenium complexes inhibit the fibril formation of human islet amyloid polypeptide

Abstract

The deposition of human islet amyloid polypeptide (hIAPP) is closely correlated with type II diabetes mellitus (T2DM). hIAPP misfolding, as a significant causative factor of T2DM, can lead to the failure of islet transplant. Therefore, preventing the aggregation of hIAPP is one of the most vital factors to treat T2DM. Mononuclear Ru complexes have recently been proved to inhibit the aggregation of hIAPP. In the present work, the influences of three water-soluble binuclear Ru complexes, namely, Na2[{trans-RuCl4(DMSO)}2(μ-pyz)] (1), Na2[{trans-RuCl4(DMSO)}2(μ-pym)] (2), and Na2[{trans-RuCl4(DMSO)}2(μ-bipy)] (3), on hIAPP fibril formation with mononuclear compounds were determined and compared. Results indicated that the three binuclear Ru complexes effectively inhibited the fibrillation of hIAPP to form nanoscale particles and decreased the β-sheet component of peptides, thus reducing the cytotoxicity induced by hIAPP. Binuclear Ru complexes showed better inhibition ability than their corresponding mononuclear Ru complexes, which might be attributed to the second metal center. Our study provided new insights into the design of multinuclear Ru complexes as potential metallodrugs against T2DM.