Increased Cation Conductance in Human Erythrocytes Artificially Aged by Glycation

Increased Cation Conductance in Human Erythrocytes Artificially Aged by Glycation Excessive glucose concentrations foster glycation and thus premature aging of erythrocytes. The present study explored whether glycation-induced erythrocyte aging is paralleled by features of suicidal erythrocyte death or eryptosis, which is characterized by cell membrane scrambling with subsequent phosphatidylserine exposure at the cell surface and cell shrinkage. Both are triggered by increases of cytosolic Ca2+ concentration ([Ca2+]i), which may result from activation of Ca2+ permeable cation channels. Glycation was accomplished by exposure to high glucose concentrations (40 and 100 mM), phosphatidylserine exposure estimated from annexin binding, cell shrinkage from decrease of forward scatter, and [Ca2+]i from Fluo3-fluorescence in analysis via fluorescence-activated cell sorter. Cation channel activity was determined by means of whole-cell patch clamp. Glycation of total membrane proteins, immunoprecipitated TRPC3/6/7, and immunoprecipitated L-type Ca2+ channel proteins was estimated by Western blot testing with polyclonal antibodies used against advanced glycation end products. A 30–48-h exposure of the cells to 40 or 100 mM glucose in Ringer solution (at 37°C) significantly increased glycation of membrane proteins, hemoglobin (HbA1c), TRPC3/6/7, and L-type Ca2+ channel proteins, enhanced amiloride-sensitive, voltage-independent cation conductance, [Ca2+]i, and phosphatidylserine exposure, and led to significant cell shrinkage. Ca2+ removal and addition of Ca2+ chelator EGTA prevented the glycation-induced phosphatidylserine exposure and cell shrinkage after glycation. Glycation-induced erythrocyte aging leads to eryptosis, an effect requiring Ca2+ entry from extracellular space. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

Increased Cation Conductance in Human Erythrocytes Artificially Aged by Glycation

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Publisher
Springer-Verlag
Copyright
Copyright © 2010 by Springer Science+Business Media, LLC
Subject
Life Sciences; Human Physiology ; Biochemistry, general
ISSN
0022-2631
eISSN
1432-1424
D.O.I.
10.1007/s00232-010-9265-2
Publisher site
See Article on Publisher Site

Abstract

Excessive glucose concentrations foster glycation and thus premature aging of erythrocytes. The present study explored whether glycation-induced erythrocyte aging is paralleled by features of suicidal erythrocyte death or eryptosis, which is characterized by cell membrane scrambling with subsequent phosphatidylserine exposure at the cell surface and cell shrinkage. Both are triggered by increases of cytosolic Ca2+ concentration ([Ca2+]i), which may result from activation of Ca2+ permeable cation channels. Glycation was accomplished by exposure to high glucose concentrations (40 and 100 mM), phosphatidylserine exposure estimated from annexin binding, cell shrinkage from decrease of forward scatter, and [Ca2+]i from Fluo3-fluorescence in analysis via fluorescence-activated cell sorter. Cation channel activity was determined by means of whole-cell patch clamp. Glycation of total membrane proteins, immunoprecipitated TRPC3/6/7, and immunoprecipitated L-type Ca2+ channel proteins was estimated by Western blot testing with polyclonal antibodies used against advanced glycation end products. A 30–48-h exposure of the cells to 40 or 100 mM glucose in Ringer solution (at 37°C) significantly increased glycation of membrane proteins, hemoglobin (HbA1c), TRPC3/6/7, and L-type Ca2+ channel proteins, enhanced amiloride-sensitive, voltage-independent cation conductance, [Ca2+]i, and phosphatidylserine exposure, and led to significant cell shrinkage. Ca2+ removal and addition of Ca2+ chelator EGTA prevented the glycation-induced phosphatidylserine exposure and cell shrinkage after glycation. Glycation-induced erythrocyte aging leads to eryptosis, an effect requiring Ca2+ entry from extracellular space.

Journal

The Journal of Membrane BiologySpringer Journals

Published: Jun 6, 2010

References

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