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Regulation of erythrocyte survival by AMP‐activated protein kinase
Author(s) -
Föller Michael,
Sopjani Mentor,
Koka Saisudha,
Gu Shuchen,
Mahmud Hasan,
Wang Kan,
Floride Elisa,
Schleicher Erwin,
Schulz Eberhard,
Münzel Thomas,
Lang Florian
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.08-121772
Subject(s) - ampk , ionomycin , protein kinase a , medicine , endocrinology , amp activated protein kinase , chemistry , cytosol , activator (genetics) , apoptosis , kinase , biology , stimulation , biochemistry , enzyme , receptor
AMP‐activated protein kinase (AMPK), an energy‐sensing enzyme, counteracts energy depletion by stimulation of energy production and limitation of energy utilization. On energy depletion, erythrocytes undergo suicidal death or eryptosis, triggered by an increase in cytosolic Ca 2+ activity ([Ca 2+ ] i ) and characterized by cell shrinkage and phosphatidylserine (PS) exposure at the erythrocyte surface. The present study explored whether AMPK participates in the regulation of eryptosis. Western blotting and confocal microscopy disclosed AMPK expression in erythrocytes. [Ca 2+ ] i (Fluo3 fluorescence), cell volume (forward scatter), and PS exposure (annexin V binding) were determined by fluorescence‐activated cell sorting (FACS) analysis. Glucose removal increased [Ca 2+ ] i , decreased cell volume, and increased PS exposure. The AMPK‐inhibitor compound C (20 µM) did not significantly modify eryptosis under glucose‐replete conditions but significantly augmented the eryptotic effect of glucose withdrawal. An increase in [Ca 2+ ] i by Ca 2+ ionophore ionomycin triggered eryptosis, an effect blunted by the AMPK activator 5‐aminoimidazole‐4‐carboxamide‐1‐β‐D‐ribofuranoside (AICAR;1 mM). As compared with erythrocytes from wild‐type littermates ( ampk +/+ ), erythrocytes from AMPKctl‐deficient mice ( ampk − / − ) were significantly more susceptible to the eryptotic effect of energy depletion. The ampk − / − mice were anemic despite excessive reticulocytosis, and they suffered from severe splenomegaly, again pointing to enhanced erythrocyte turnover. The observations disclose a critical role of AMPK in the survival of circulating erythrocytes.—Föller, M., Sopjani, M., Koka, S., Gu, S., Mahmud, H., Wang, K., Floride, E., Schleicher, E., Schulz, E., Münzel, T., Lang, F. Regulation of erythrocyte survival by AMP‐activated protein kinase. FASEB J . 23, 1072–1080 (2009)