Author(s):
Ferreira, Ana ; Rivera, Alicia ; Wohlgemuth, Jay G. ; Dlott, Jeffrey S. ; Snyder, L. Michael ; Alper, Seth L. ; Romero, Jose R.
Date: 2022
Persistent ID: http://hdl.handle.net/10362/144598
Origin: Repositório Institucional da UNL
Project/scholarship:
info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDB%2F04647%2F2020/PT;
info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDP%2F04647%2F2020/PT;
Subject(s): Cell magnesium; Diabetes mellitus; IIon exchange; Ion flux; Ion transporter; Red blood cells; Developmental Biology; Cell Biology; SDG 3 - Good Health and Well-being
Description
CEECIND/01053/2017 UIDB/04647/2020 UIDP/04647/2020
Hyperglycemia is associated with decreased Mg2+ content in red blood cells (RBC), but mechanisms remain unclear. We characterized the regulation of Mg2+ efflux by glucose in ex vivo human RBC. We observed that hemoglobin A1C (HbA1C) values correlated with Na+-dependent Mg2+ efflux (Na+/Mg2+ exchange) and inversely correlated with cellular Mg content. Treatment of cells with 50 mM D-glucose, but not with sorbitol, lowered total cellular Mg (2.2 ± 0.1 to 2.0 ± 0.1 mM, p < 0.01) and enhanced Na+/Mg2+ exchange activity [0.60 ± 0.09 to 1.12 ± 0.09 mmol/1013 cell × h (flux units, FU), p < 0.05]. In contrast, incubation with selective Src family kinase inhibitors PP2 or SU6656 reduced glucose-stimulated exchange activation (p < 0.01). Na+/Mg2+ exchange activity was also higher in RBC from individuals with type 2 diabetes (T2D, 1.19 ± 0.13 FU) than from non-diabetic individuals (0.58 ± 0.05 FU, p < 0.01). Increased Na+/Mg2+ exchange activity in RBC from T2D subjects was associated with lower intracellular Mg content. Similarly increased exchange activity was evident in RBC from the diabetic db/db mouse model as compared to its non-diabetic control (p < 0.03). Extracellular exposure of intact RBC from T2D subjects to recombinant peptidyl-N-glycosidase F (PNGase F) reduced Na+/Mg2+ exchange activity from 0.98 ± 0.14 to 0.59 ± 0.13 FU (p < 0.05) and increased baseline intracellular Mg content (1.8 ± 0.1 mM) to normal values (2.1 ± 0.1 mM, p < 0.05). These data suggest that the reduced RBC Mg content of T2D RBC reflects enhanced RBC Na+/Mg2+ exchange subject to regulation by Src family kinases and by the N-glycosylation state of one or more membrane proteins. The data extend our understanding of dysregulated RBC Mg2+ homeostasis in T2D.
