Leptin Delivers β‐cell‐derived C‐peptide to Red Blood Cells

Abstract

It was recently reported that C‐peptide, the connecting peptide of proinsulin, binds to red blood cells (RBCs) when delivered by albumin. Additionally, treatment of RBCs with C‐peptide, zinc, and albumin results in an increase in ATP release from the RBC and downstream production of endothelium‐derived nitric oxide. Here, we report leptin, an adipocyte‐derived cytokine known for its importance for energy balance and potential glucoregulatory effects, as a potential drug carrier for C‐peptide. Here, we report that C‐peptide increases GLUT1 translocation and ATP release from RBCs, but only in the presence of leptin and zinc. To investigate the nature of the interaction of C‐peptide and leptin with RBCs we have utilized leptin labeled with technetium‐99m (99mTc) to perform saturation binding studies. Samples containing 7% RBCs were treated with different concentrations of labeled leptin and 20 nM C‐peptide. Samples were then incubated, centrifuged, and washed several times prior to quantitative determination of gamma emission from the 99mTc‐labeled leptin bound to the RBCs. Data was correlated back to a standard curve of labeled leptin, and a saturation binding curve was generated. Initial results suggest that total binding of labeled leptin, in the presence of C‐peptide, begins to saturate when 200 picomoles of labeled leptin are added to the RBCs.Support or Funding InformationNational Institutes of HealthThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.