Mesencephalic astrocyte-derived neurotrophic factor is an ischemia-inducible secreted endoplasmic reticulum stress response protein in the heart

Archana Tadimalla, Peter J. Belmont, Donna J. Thuerauf, Matthew S. Glassy, Joshua J. Martindale, Natalie Gude, Mark A. Sussman, Christopher C. Glembotski

Research output: Contribution to journalArticlepeer-review

117 Scopus citations

Abstract

The endoplasmic reticulum (ER) stress response (ERSR) is activated when folding of nascent proteins in the ER lumen is impeded. Myocardial ischemia was recently shown to activate the ERSR; however, the role of this complex signaling system in the heart is not well understood. ER stress activates the transcription factor ATF6, which induces expression of proteins targeted to the ER, where they restore protein folding, thus fostering cytoprotection. We previously developed a transgenic mouse line that expresses a conditionally activated form of ATF6 in the heart. In this mouse line, ATF6 activation decreased ischemic damage in an ex vivo model of myocardial ischemia/reperfusion and induced numerous genes, including mesencephalic astrocyte-derived neurotrophic factor (MANF). In the present study, MANF expression was shown to be induced in cardiac myocytes and in other cell types in the hearts of mice subjected to in vivo myocardial infarction. Additionally, simulated ischemia induced MANF in an ATF6-dependent manner in neonatal rat ventricular myocyte cultures. In contrast to many other ER-resident ERSR proteins, MANF lacks a canonical ER-retention sequence, consistent with our finding that MANF was readily secreted from cultured cardiac myocytes. Knockdown of endogenous MANF with micro-RNA increased cell death upon simulated ischemia/reperfusion, whereas addition of recombinant MANF to media protected cultured cardiac myocytes from simulated ischemia/reperfusion-mediated death. Thus, a possible function of the ERSR in the heart is the ischemia-mediated induction of secreted proteins, such as MANF, that can function in an autocrine/paracrine manner to modulate myocardial damage from ER stresses, including ischemia.

Original languageEnglish (US)
Pages (from-to)1249-1258
Number of pages10
JournalCirculation research
Volume103
Issue number11
DOIs
StatePublished - Nov 21 2008
Externally publishedYes

Keywords

  • Adenovirus
  • Cardiac myocytes
  • Endoplasmic reticulum stress
  • Hypoxia
  • Ischemia
  • Myocardial infarction
  • Unfolded protein response

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

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