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Nuclear factor erythroid derived‐2 (NF‐E2)‐mediated regulation of NF‐kB activation in neutrophils: A potential mechanism of NF‐E2‐mediated apoptosis
Author(s) -
Johnson Paul R,
Cummins Timothy D,
Manning Terri R,
Wu Rui,
Sachleben Leroy R,
Gozal Evelyne,
Rane Madhavi J
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/fasebj.23.1_supplement.526.6
Subject(s) - nf κb , propidium iodide , apoptosis , transfection , luciferase , microbiology and biotechnology , nfkb1 , iκbα , chemistry , flow cytometry , phosphorylation , transcription factor , biology , cancer research , programmed cell death , gene , biochemistry
Neutrophils (PMNs) are short‐lived cells that constitutively undergo apoptosis to prevent excessive tissue damage. We previously identified NF‐E2 as an Akt substrate in human PMNs, and showed that antibody depletion of NF‐E2 delayed PMN apoptosis at 24 hours as assessed by propidium iodide flow cytometry. Additionally, NF‐E2 depletion of PMNs increased IκB phosphorylation, a marker of NFκB activation with concomitant increases in pro‐survival Mcl‐1 expression. These studies led us to hypothesize that NF‐E2 promotes constitutive PMN apoptosis by inhibiting NFκB activation. Preliminary EMSA revealed increased PMN NFκB DNA binding after NF‐E2 depletion. Furthermore, co‐transfection of HEK‐293 cells with NF‐E2 and NFκB luciferase reporter resulted in significantly lower NFκB luciferase promoter activity after TNF‐α stimulation as compared to vector and NFκB luciferase reporter transfected cells. These results collectively demonstrate that NF‐E2 regulates PMN apoptosis by inhibiting NFκB activity. In our future studies, we will utilize NFκB inhibitors to further delineate a role for NFκB in promoting PMN survival and Mcl‐1 expression as a consequence of NF‐E2 depletion. Taken together, our results suggest that NF‐E2 is a pro‐apoptotic protein that promotes constitutive PMN apoptosis by inhibiting NFκB‐mediated transcription of pro‐survival genes. Support for this work was provided by AHA #0815433D (PRJ) and AHA #0335278N, NIH/NIAID #1R56AI059165‐01A2, RO1AI075212‐01A1 (MJR). ASBMMB abstract, EB2009, Deadline November 5, 2008