mIGF-1/JNK1/SirT1 signaling confers protection against oxidative stress in the heart Manlio Vinciguerra, 1,2 Maria Paola Santini, 3 Conception Martinez, 1 Valerio Pazienza, 4 William C. Claycomb, 5 Alessandro Giuliani 6 and Nadia Rosenthal 1,3 1 European Molecular Biology Laboratory (EMBL)-Mouse Biology Unit, Campus A. Buzzati-Traverso, Monterotondo-Scalo, Roma 00016, Italy 2 European Molecular Biology Laboratory (EMBL)-Genome Biology Unit, Meyerhofstraße, Heidelberg 69117, Germany 3 Harefield Heart Science Centre, Imperial College London, Harefield, Middlesex UB9 6JH, UK 4 Gastroenterology Unit, I.R.C.C.S. ‘‘Casa Sollievo della Sofferenza’’ Hospital, San Giovanni Rotondo (FG), Italy 5 Department of Biochemistry and Molecular Biology, Louisiana State Univ. Health Sciences Center, New Orleans, Lousiana 1901, USA 6 Environment and Health Department, Istituto Superiore di Sanita ` , Viale Regina Elena 299, 00161 Roma, Italy Summary Oxidative stress contributes to the pathogenesis of aging-associ- ated heart failure. Among various signaling pathways mediating oxidative stress, the NAD + -dependent protein deacetylase SirT1 has been implicated in the protection of heart muscle. Expres- sion of a locally acting insulin-like growth factor-1 (IGF-1) pro- peptide (mIGF-1) helps the heart to recover from infarct and enhances SirT1 expression in cardiomyocytes (CM) in vitro, exert- ing protection from hypertrophic and oxidative stresses. To study the role of mIGF-1 ⁄ SirT1 signaling in vivo, we generated cardiac-specific mIGF-1 transgenic mice in which SirT1 was depleted from adult CM in a tamoxifen-inducible and conditional fashion. Analysis of these mice confirmed that mIGF-1-induced SirT1 activity is necessary to protect the heart from paraquat (PQ)-induced oxidative stress and lethality. In cultured CM, mIGF-1 increases SirT1 expression through a c-Jun NH(2)-terminal protein kinase 1 (JNK1)-dependent signaling mechanism. Thus, mIGF-1 protects the heart from oxidative stress via SirT1 ⁄ JNK1 activity, suggesting new avenues for cardiac therapy during aging and heart failure. Keywords: insulin-like growth factor-1; Sirtuin-1; oxidative stress; cardiomyocytes. Introduction Chronic congestive heart failure carries a poor prognosis and is a lead- ing cause of cardiovascular death (McMurray & Stewart, 2000). Despite advances in treatment, the underlying age-dependent process that leads to cardiac dysfunction remains not fully understood. The early pioneering free radical theory of aging implicates multi-organ accumu- lation of free radical damage (Harman, 1956), which has been more recently expanded to encompass oxidative damage from mitochondrial reactive oxygen species (ROS). Accumulating evidence suggests that ROS signaling plays an important role in the development and progres- sion of age-associated heart failure, regardless of the etiology (Anilku- mar et al., 2009). Studies in rodent models implicate ROS in the development of car- diac hypertrophy, cardiomyocyte apoptosis, and the remodeling of the failing heart following myocardial infarction, pressure overload, or aging (Giordano, 2005; Takimoto & Kass, 2007) and have suggested a possible causal role for increased ROS in the development of age-medi- ated cardiac vulnerability and contractile dysfunction (Jahangir et al., 2007). From a therapeutic perspective, the precise antioxidant potential of car- dioprotective pathways is not completely understood. Elucidation of spe- cific cell signaling pathways that counteract the deleterious effects of oxidative stress is therefore important for developing strategies to limit myocardial dysfunction in the elderly. Among these signaling pathways, insulin-like growth factor-1 (IGF-1) and Sirtuin-1 (SirT1) have emerged as fundamental mediators of cell sur- vival, oxidative stress, and lifespan regulation in several tissues including the heart (Delaughter et al., 1999; Kajstura et al., 2001; Li et al., 2007; SantiNi et al., 2007; Vinciguerra et al., 2009; Donmez & Guarente, 2010; Kenyon, 2010; Vinciguerra et al., 2010). IGF-1 is a peptide hormone acting as a systemic growth factor pro- duced mainly by the adult liver and as a local growth and differentiation factor functioning in an autocrine ⁄ paracrine manner in tissues such as heart muscle (Winn 2002 1 ; Barton, 2006; Santini et al., 2007). Multiple IGF-1 propeptides produced by alternate exon splicing are cleaved to yield a common 70-amino acid core hormone that is released into the blood- stream and has been implicated in the restriction of lifespan and in cardio- vascular diseases (Andreassen et al., 2009; Kenyon, 2010). By contrast, the locally acting mIGF-1 propeptide (Musaro et al., 2001) includes the C-terminal Ea extension peptide and is highly expressed in neonatal tis- sues and adult liver but decreases during aging. In skeletal muscle, adult mIGF-1 expression levels increase transiently in response to local damage (Winn et al., 2002; Matheny et al., 2010) 2 . The fact that IGF-1 can act either as a circulating hormone or as a local growth factor has led to conflicting results from analyses of its role in cardiovascular function (during development or in response to oxidative challenge) and from studies in which different transgenic IGF-1 isoforms were synthesized in extrahepatic mouse tissues (Delaughter et al., 1999; Kajstura et al., 2001; Li et al., 2007), underscoring the physiological differences between IGF-1 propeptides versus mature IGF-1 peptide. We have previously shown that continuous cardiomyocyte (CM)- restricted expression of the mIGF-1 propeptide throughout postnatal life did not perturb cardiac physiology or induce a pathological phenotype (Santini et al., 2007). Molecular analysis revealed further that mIGF-1 enhanced antioxidative cell defenses by upregulating a subset of protect- ing genes such as adiponectin, uncoupling protein 1 (UCP1), and metallo- thionein 2 (MT-2) (Santini et al., 2007). We recently uncovered SirT1 as another downstream mediator of mIGF-1 action in the heart (Vinciguerra 2009) 3 . SirT1 belongs to the sirtuin family of nicotinamide adenine dinucleotide NAD-dependent protein deacetylases, whose activation appears beneficial for aging- associated metabolic, inflammatory, and cardiac diseases, and to A C E L 7 6 6 B Dispatch: 11.11.11 Journal: ACEL CE: Krithika P. Journal Name Manuscript No. Author Received: No. of pages: 11 PE: Ramya Correspondence Manlio Vinciguerra, European Molecular Biology Laboratory, Campus ‘‘Adriano Buzzati-Traverso’’, Via Ramarini 32, 00016 Monterotondo, Italy. Tel.: +39 06 90091339; fax: +39 06 90091406; e-mail: Manlio.Vinciguerra@embl.it Accepted for publication 25 October 2011 ª 2011 The Authors Aging Cell ª 2011 Blackwell Publishing Ltd/Anatomical Society of Great Britain and Ireland 1 Aging Cell (2011) pp1–11 Doi: 10.1111/j.1474-9726.2011.00766.x 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55