Proposed Dynamics of CDB3 Activation in Human Erythrocytes by Nifedipine Studied with Scanning Flow Cytometry
Ekaterina S Yastrebova1,2,3, Anastasiya I Konokhova1,3, Dmitry I Strokotov1,4
1Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya 3, Novosibirsk, 630090, Russia.
Insights
Nifedipine significantly increases the anion exchanger Band 3 (CDB3) activity in human erythrocytes by influencing intracellular calcium dynamics. This study clarifies the molecular mechanism of nifedipine
Area of Science:
- Pharmacology
- Biophysics
- Cell Biology
Background:
- Nifedipine is a widely used calcium channel blocker.
- Its precise mechanisms of action in blood, particularly on erythrocytes, remain unclear.
- Understanding nifedipine's effects on erythrocyte function is crucial for its therapeutic application.
Purpose of the Study:
- To investigate the influence of nifedipine on human erythrocyte function.
- To elucidate the molecular mechanisms underlying nifedipine's effects on anion transport.
- To quantify the kinetics of Band 3 anion exchanger activation and deactivation.
Main Methods:
- Scanning flow cytometry was employed to observe erythrocyte dynamics.
- Experimental measurements focused on the transmembrane exchange rate of HCO3-/Cl-.
- A kinetic model was developed to explain the observed experimental data.
Main Results:
- Nifedipine significantly increases the transmembrane exchange rate of HCO3-/Cl- mediated by Band 3 (CDB3) in human erythrocytes.
- The rate of CDB3 activation is not limited by nifedipine binding or Ca2+ transport.
- A kinetic model suggests CDB3 activation is limited by intracellular Ca2+ interaction and spontaneous deactivation.
Conclusions:
- Nifedipine's action on human erythrocytes involves modulating the Band 3 anion exchanger (CDB3).
- The study provides quantitative insights into the molecular kinetic mechanism of nifedipine's effect on erythrocyte anion transport.
- Scanning flow cytometry proved effective in clarifying these complex cellular dynamics.
Abstract:
Nifedipine is calcium channels and pumps blocker widely used in medicine. However, mechanisms of nifedipine action in blood are not clear. In particular, the influence of nifedipine on erythrocytes is far from completely understood. In this work, applying scanning flow cytometry, we observed experimentally for the first time the dynamics behind a significant increase of HCO3- /Cl- transmembrane exchange rate of CDB3 (main anion exchanger, AE1, Band 3, SLC4A1) of human erythrocytes in the presence of nifedipine in blood. It was found that the rate of CDB3 activation is not limited by the rate of nifedipine binding and/or Ca2+ transport. In order to explain the experimental data, we suggested a kinetic model assuming that the rate of CDB3 activation is limited by the dynamics of the balance between two intracellular processes (1) the activation of CDB3 limited by its interaction with intracellular Ca2+ , and (2) the spontaneous deactivation of CDB3. Thus the use of scanning flow cytometry allowed to clarify quantitatively the molecular kinetic mechanism of nifedipine action on human erythrocytes. In particular, the efficiency (~30) and rates of activation (~0.3 min-1 ) and deactivation (~10-3 min-1 ) of CDB3 in human erythrocytes was evaluated for two donors. © 2019 International Society for Advancement of Cytometry.
