title: β-Adrenergic receptor-mediated transactivation of epidermal growth factor receptor decreases cardiomyocyte apoptosis through differential subcellular activation of ERK1/2 and Akt.
abstract: β-Adrenergic receptor (βAR)-mediated transactivation of epidermal growth factor receptor (EGFR) has been shown to relay pro-survival effects via unknown mechanisms. We hypothesized that acute βAR-mediated EGFR transactivation in the heart promotes differential subcellular activation of ERK1/2 and Akt, promoting cell survival through modulation of apoptosis. C57BL/6 mice underwent acute i.p. injection with isoproterenol (ISO)±AG 1478 (EGFR antagonist) to assess the impact of βAR-mediated EGFR transactivation on the phosphorylation of ERK1/2 (P-ERK1/2) and Akt (P-Akt) in distinct cardiac subcellular fractions. Increased P-ERK1/2 and P-Akt were observed in cytosolic, plasma membrane and nuclear fractions following ISO stimulation. Whereas the P-ERK1/2 response was EGFR-sensitive in all fractions, the P-Akt response was EGFR-sensitive only in the plasma membrane and nucleus, results confirmed in primary rat neonatal cardiomyocytes (RNCM). βAR-mediated EGFR-transactivation also decreased apoptosis in serum-depleted RNCM, as measured via TUNEL as well as caspase 3 activity/cleavage, which were sensitive to the inhibition of either ERK1/2 (PD184352) or Akt (LY-294002) signaling. Caspase 3 activity/cleavage was also sensitive to the inhibition of transcription, which, with an increase in nuclear P-ERK1/2 and P-Akt in response to ISO, suggested that βAR-mediated EGFR transactivation may regulate apoptotic gene transcription. An Apoptosis PCR Array identified tnfsf10 (TRAIL) to be altered by ISO in an EGFR-sensitive manner, results confirmed via RT-PCR and ELISA measurement of both membrane-bound and soluble cardiomyocyte TRAIL levels. βAR-mediated EGFR transactivation induces differential subcellular activation of ERK1/2 and Akt leading to increased cell survival through the modulation of caspase 3 activity and apoptotic gene expression in cardiomyocytes.
authors.affiliation: Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA.
authors.forename: Laurel A
authors.initials: LA
authors.lastname: Grisanti
authors.affiliation: Department of Pharmaceutical Sciences, Jefferson School of Pharmacy, Thomas Jefferson University, Philadelphia, PA 19107, USA.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Talarico
authors.affiliation: Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA.
authors.forename: Rhonda L
authors.initials: RL
authors.lastname: Carter
authors.affiliation: Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA.
authors.forename: Justine E
authors.initials: JE
authors.lastname: Yu
authors.affiliation: Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA.
authors.forename: Ashley A
authors.initials: AA
authors.lastname: Repas
authors.affiliation: Department of Pharmaceutical Sciences, Jefferson School of Pharmacy, Thomas Jefferson University, Philadelphia, PA 19107, USA.
authors.forename: Scott W
authors.initials: SW
authors.lastname: Radcliffe
authors.affiliation: Department of Pharmaceutical Sciences, Jefferson School of Pharmacy, Thomas Jefferson University, Philadelphia, PA 19107, USA.
authors.forename: Hoang-Ai
authors.initials: HA
authors.lastname: Tang
authors.affiliation: Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, PA 19140, USA.
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Makarewich
authors.affiliation: Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, PA 19140, USA.
authors.forename: Steven R
authors.initials: SR
authors.lastname: Houser
authors.affiliation: Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA; Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, USA. Electronic address: douglas.tilley@temple.edu.
authors.forename: Douglas G
authors.initials: DG
authors.lastname: Tilley
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D002415:Cats; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D007545:Isoproterenol / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics* / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics* / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation; D061251:Primary Cell Culture; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics* / Q000378:metabolism; D011799:Quinazolines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011943:Receptors, Adrenergic, beta / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction; D020032:Tyrphostins / Q000494:pharmacology
chemical_list: D000318:Adrenergic beta-Agonists; D011799:Quinazolines; D011943:Receptors, Adrenergic, beta; D020032:Tyrphostins; C101044:RTKI cpd; C541485:EGFR protein, mouse; D066246:ErbB Receptors; D051057:Proto-Oncogene Proteins c-akt; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D053148:Caspase 3; D007545:Isoproterenol
keywords: Apoptosis; Cardiomyocyte; Epidermal growth factor receptor; β-Adrenergic receptor