title: Novel regulation of cardiac metabolism and homeostasis by the adrenomedullin-receptor activity-modifying protein 2 system.
abstract: Adrenomedullin (AM) was identified as a vasodilating and hypotensive peptide mainly produced by the cardiovascular system. The AM receptor calcitonin receptor-like receptor associates with receptor activity-modifying protein (RAMP), one of the subtypes of regulatory proteins. Among knockout mice ((-/-)) of RAMPs, only RAMP2(-/-) is embryonically lethal with cardiovascular abnormalities that are the same as AM(-/-). This suggests that the AM-RAMP2 system is particularly important for the cardiovascular system. Although AM and RAMP2 are highly expressed in the heart from embryo to adulthood, their analysis has been limited by the embryonic lethality of AM(-/-) and RAMP2(-/-). For this study, we generated inducible cardiac myocyte-specific RAMP2(-/-) (C-RAMP2(-/-)). C-RAMP2(-/-) exhibited dilated cardiomyopathy-like heart failure with cardiac dilatation and myofibril disruption. C-RAMP2(-/-) hearts also showed changes in mitochondrial structure and downregulation of mitochondria-related genes involved in oxidative phosphorylation, β-oxidation, and reactive oxygen species regulation. Furthermore, the heart failure was preceded by changes in peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α), a master regulator of mitochondrial biogenesis. Metabolome and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF-MS) imaging analyses revealed early downregulation of cardiolipin, a mitochondrial membrane-specific lipid. Furthermore, primary-cultured cardiac myocytes from C-RAMP2(-/-) showed reduced mitochondrial membrane potential and enhanced reactive oxygen species production in a RAMP2 deletion-dependent manner. C-RAMP2(-/-) showed downregulated activation of cAMP response element binding protein (CREB), one of the main regulators of mitochondria-related genes. These data demonstrate that the AM-RAMP2 system is essential for cardiac metabolism and homeostasis. The AM-RAMP2 system is a promising therapeutic target of heart failure.
authors.affiliation: Department of Cardiovascular Research, Shinshu University Graduate School of Medicine, Asahi 3-1-1, Matsumoto, Nagano, 390-8621, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Yoshizawa
authors.forename: Takayuki
authors.initials: T
authors.lastname: Sakurai
authors.forename: Akiko
authors.initials: A
authors.lastname: Kamiyoshi
authors.forename: Yuka
authors.initials: Y
authors.lastname: Ichikawa-Shindo
authors.forename: Hisaka
authors.initials: H
authors.lastname: Kawate
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Iesato
authors.forename: Teruhide
authors.initials: T
authors.lastname: Koyama
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Uetake
authors.forename: Lei
authors.initials: L
authors.lastname: Yang
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yamauchi
authors.forename: Megumu
authors.initials: M
authors.lastname: Tanaka
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Toriyama
authors.forename: Kyoko
authors.initials: K
authors.lastname: Igarashi
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nakada
authors.forename: Toshihide
authors.initials: T
authors.lastname: Kashihara
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Yamada
authors.forename: Hayato
authors.initials: H
authors.lastname: Kawakami
authors.forename: Hiroki
authors.initials: H
authors.lastname: Nakanishi
authors.forename: Ryo
authors.initials: R
authors.lastname: Taguchi
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Nakanishi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Akazawa
authors.forename: Takayuki
authors.initials: T
authors.lastname: Shindo
mesh_terms: D053607:Adrenomedullin / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002311:Cardiomyopathy, Dilated / Q000235:genetics / Q000378:metabolism; D006706:Homeostasis / Q000502:physiology*; D051379:Mice; D008822:Mice, Transgenic; D008929:Mitochondria, Heart / Q000378:metabolism; D063269:Mitochondrial Turnover; D009206:Myocardium / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000378:metabolism; D058263:Receptor Activity-Modifying Protein 2 / Q000235:genetics / Q000378:metabolism*; D058265:Receptors, Adrenomedullin / Q000235:genetics / Q000378:metabolism*
chemical_list: C545506:Ramp2 protein, mouse; D058263:Receptor Activity-Modifying Protein 2; D058265:Receptors, Adrenomedullin; D053607:Adrenomedullin; D002118:Calcium