title: Hypoxia-driven sarcoplasmic/endoplasmic reticulum calcium ATPase 2 (SERCA2) downregulation depends on low-density lipoprotein receptor-related protein 1 (LRP1)-signalling in cardiomyocytes.
abstract: The maintenance of sarcoplasmic reticulum Ca(2+) ATPase (SERCA2) activity is crucial for cardiac function and SERCA2 is dramatically reduced in the heart exposed to hypoxic/ischemic conditions. Previous work from our group showed that hypoxia upregulates the phosphorylated form of the Ca(2+)-dependent nonreceptor protein tyrosine kinase (PTK) proline-rich tyrosine kinase 2 (pPyk2) protein levels in a low-density lipoprotein receptor-related protein (LRP1)-dependent manner. Pyk2 in turn may modulate SERCA2 in cardiomyocytes although this remains controversial. We therefore aimed to investigate the role of LRP1 on hypoxia-induced SERCA2 depletion in cardiomyocytes and to establish LRP1 signalling mechanisms involved. Western blot analysis showed that hypoxia reduced SERCA2 concomitantly with a sustained increase in LRP1 and pPyk2 protein levels in HL-1 cardiomyocytes. By impairing hypoxia-induced Pyk2 phosphorylation and HIF-1α accumulation, LRP1 deficiency prevented SERCA2 depletion and reduction of the sarcoplasmic reticulum calcium content in cardiomyocytes. Moreover, the inhibition of Pyk2 phosphorylation (with the Src-family inhibitor PP2) or the specific silencing of Pyk2 (with siRNA-anti Pyk2) preserved low HIF-1α and high SERCA2 levels in HL-1 cardiomyocytes exposed to hypoxia. We determined that the LRP1/Pyk2 axis represses SERCA2 mRNA expression via HIF-1α since HIF-1α overexpression abolished the protective effect of LRP1 deficiency on SERCA2 depletion. Our findings show a crucial role of LRP1/Pyk2/HIF-1α in hypoxia-induced cardiomyocyte SERCA2 downregulation, a pathophysiological process closely associated with heart failure.
authors.affiliation: Cardiovascular Research Center, CSIC-ICCC, IIB-Sant Pau, Barcelona, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Revuelta-López
authors.affiliation: Cardiovascular Research Center, CSIC-ICCC, IIB-Sant Pau, Barcelona, Spain.
authors.forename: Roi
authors.initials: R
authors.lastname: Cal
authors.affiliation: Cardiovascular Research Center, CSIC-ICCC, IIB-Sant Pau, Barcelona, Spain.
authors.forename: Adela
authors.initials: A
authors.lastname: Herraiz-Martínez
authors.affiliation: Cardiovascular Research Center, CSIC-ICCC, IIB-Sant Pau, Barcelona, Spain.
authors.forename: David
authors.initials: D
authors.lastname: de Gonzalo-Calvo
authors.affiliation: Cardiovascular Research Center, CSIC-ICCC, IIB-Sant Pau, Barcelona, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Nasarre
authors.affiliation: ICREC Research Program, Health Science Research Institute Germans Trias i Pujol, Can Ruti Campus, Badalona, Spain.
authors.forename: Santiago
authors.initials: S
authors.lastname: Roura
authors.affiliation: ICREC Research Program, Health Science Research Institute Germans Trias i Pujol, Can Ruti Campus, Badalona, Spain.
authors.forename: Carolina
authors.initials: C
authors.lastname: Gálvez-Montón
authors.affiliation: ICREC Research Program, Health Science Research Institute Germans Trias i Pujol, Can Ruti Campus, Badalona, Spain.
authors.forename: Antoni
authors.initials: A
authors.lastname: Bayes-Genis
authors.affiliation: Cardiovascular Research Center, CSIC-ICCC, IIB-Sant Pau, Barcelona, Spain.
authors.forename: Lina
authors.initials: L
authors.lastname: Badimon
authors.affiliation: Cardiovascular Research Center, CSIC-ICCC, IIB-Sant Pau, Barcelona, Spain.
authors.forename: Leif
authors.initials: L
authors.lastname: Hove-Madsen
authors.affiliation: Cardiovascular Research Center, CSIC-ICCC, IIB-Sant Pau, Barcelona, Spain. Electronic address: cllorente@csic-iccc.org.
authors.forename: Vicenta
authors.initials: V
authors.lastname: Llorente-Cortés
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling; D015687:Cell Hypoxia; D002460:Cell Line; D015536:Down-Regulation; D004789:Enzyme Activation; D051418:Focal Adhesion Kinase 2 / Q000378:metabolism; D020868:Gene Silencing; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D051379:Mice; D017202:Myocardial Ischemia / Q000201:enzymology; D009206:Myocardium / Q000201:enzymology; D032383:Myocytes, Cardiac / Q000378:metabolism*; D011973:Receptors, LDL / Q000378:metabolism*; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000235:genetics / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000378:metabolism*
chemical_list: C497443:Hif1a protein, mouse; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D026503:Low Density Lipoprotein Receptor-Related Protein-1; C486645:Lrp1 protein, mouse; D011973:Receptors, LDL; D025521:Tumor Suppressor Proteins; D051418:Focal Adhesion Kinase 2; C496053:Ptk2b protein, mouse; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; C506947:Atp2a2 protein, mouse; D002118:Calcium
keywords: Cardiomyocytes; Hypoxia; LRP1; Pyk2; SERCA2