Novel role of HAX-1 in ischemic injury protection involvement of heat shock protein 90 Journal Article

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Authors: Lam, C. K.; Zhao, W; Cai, W.; Vafiadaki, E.; Florea, S. M.; Ren, X; Liu, Y; Robbins, N.; Zhang, Z; Zhou, X.; Jiang, M.; Rubinstein, J.; Jones, W. K.; Kranias, E. G.
Article Title: Novel role of HAX-1 in ischemic injury protection involvement of heat shock protein 90
Abstract: RATIONALE: Ischemic heart disease is characterized by contractile dysfunction and increased cardiomyocyte death, induced by necrosis and apoptosis. Increased cell survival after an ischemic insult is critical and depends on several cellular pathways, which have not been fully elucidated. OBJECTIVE: To test the hypothesis that the anti-apoptotic hematopoietic lineage substrate-1-associated protein X-1 (HAX-1), recently identified as regulator of cardiac Ca cycling, also may ameliorate cellular injury with an ischemic insult. METHODS AND RESULTS: We report that cardiac ischemia/reperfusion injury is associated with significant decreases in HAX-1 levels ex vivo and in vivo. Accordingly, overexpression of HAX-1 improved contractile recovery, coupled with reduced infarct size, plasma troponin I level, and apoptosis. The beneficial effects were associated with decreased endoplasmic reticulum (ER) stress response through specific inhibition of the inositol-requiring enzyme (IRE-1) signaling pathway, including its downstream effectors caspase-12 and the transcription factor C/EBP homologous protein. Conversely, HAX-1 heterozygous-deficient hearts exhibited increases in infarct size and IRE-1 activity. The inhibitory effects of HAX-1 were mediated by its binding to the N-terminal fragment of the heat shock protein 90 (Hsp90). Moreover, HAX-1 sequestered Hsp90 from IRE-1 to the phospholamban-sarcoplasmic/endoplasmic reticulum calcium ATPase complex. The HAX-1 regulation was further supported by loss of IRE-1 inhibition in presence of the Hsp90 inhibitor, 17-N-allylamino-17-demethoxygeldanamycin. CONCLUSIONS: Cardiac ischemia-reperfusion injury is associated with decreases in HAX-1 levels. Consequently, overexpression of HAX-1 promotes cardiomyocyte survival, mediated by its interaction with Hsp90 and specific inhibition of IRE-1 signaling at the ER/sarcoplasmic reticulum.
Journal Title: Circulation research
Volume: 112
Issue: 1
ISSN: 1524-4571; 0009-7330
Publisher: Unknown  
Journal Place: United States
Date Published: 2013
Start Page: 79
End Page: 89
Language: eng
DOI/URL:

10.1161/CIRCRESAHA.112.279935
Notes: LR: 20140109; GR: HL26057/HL/NHLBI NIH HHS/United States; GR: HL64018/HL/NHLBI NIH HHS/United States; GR: HL77101/HL/NHLBI NIH HHS/United States; GR: P50 HL077101/HL/NHLBI NIH HHS/United States; GR: R01 HL026057/HL/NHLBI NIH HHS/United States; GR: R01 HL064018/HL/NHLBI NIH HHS/United States; JID: 0047103; 0 (Benzoquinones); 0 (Biological Markers); 0 (Calcium-Binding Proteins); 0 (HSP90 Heat-Shock Proteins); 0 (Hs1bp1 protein, mouse); 0 (Lactams, Macrocyclic); 0 (Membrane Proteins); 0 (Proteins); 0 (Troponin I); 0 (phospholamban); 4GY0AVT3L4 (tanespimycin); EC 2.7.1.- (Ern2 protein, mouse); EC 2.7.11.1 (Protein-Serine-Threonine Kinases); EC 3.6.3.8 (Sarcoplasmic Reticulum Calcium-Transporting ATPases); SY7Q814VUP (Calcium); NIHMS415379; OID: NLM: NIHMS415379; OID: NLM: PMC3537902; 2012/09/14 [aheadofprint]; ppublish