Fernández-Tocino, MiguelPun-Garcia, AndrésGómez, MónicaClemente-Moragón, AgustínOliver, EduardoVillena-Gutierrez, RocíoTrigo-Anca, SofíaDíaz-Guerra, AnabelSanz-Rosa, DavidPrados, BelénDel Campo, LaraAndrés, VicenteFuster, Valentínde la Pompa, José LuisCádiz, LauraIbañez, Borja2024-11-282024-11-282024-10Basic Res Cardiol. 2024 Oct;119(5):773-794https://hdl.handle.net/20.500.12105/25814This study received funding from the Spanish Ministry of Science, Innovation and Universities (PID2022-140176OB-I00 to B.I, and PID2022-104776RB-100 to J.L.d.l.P), the European Research Council (ERC) under the European Union Horizon 2020 Research and Innovation Programme (ERC-Consolidator Grant agreement No. 819775 to B.I), the Comunidad de Madrid through the Red Madrileña de Nanomedicina en Imagen Molecular (P2022/BMD-7403 RENIMCM), Çand the CIBERCV (CB16/11/00358 to B.I, and CB16/11/00399 to J.L.d.l.P). Miguel Fernández-Tocino holds a PhD fellowship funded by the Ministerio de Ciencia e Innovación (MCIN) FPI program (PRE2020-095611). Eduardo Oliver is a Ramón y Cajal fellow funded by the Spanish Ministry of Science and Innovation MCIN/ AEI/https://doi.org/10.13039/501100011033and by “ESF Investing in your future” (RYC2020-028884-I and PID2021-123167OB-I00). The CNIC is supported by the Instituto de Salud Carlos III (ISCIII), the Ministerio de Ciencia, Innovación y Universidades (MICIU), and the Pro CNIC Foundation and is a Severo Ochoa Center of Excellence (grant CEX2020-001041-S funded by MICIN/AEI/https://doi. org/10.13039/501100011033).β3-Adrenergic receptor (β3AR) agonists have been shown to protect against ischemia-reperfusion injury (IRI). Since β3ARs are present both in cardiomyocytes and in endothelial cells, the cellular compartment responsible for this protection has remained unknown. Using transgenic mice constitutively expressing the human β3AR (hβ3AR) in cardiomyocytes or in the endothelium on a genetic background of null endogenous β3AR expression, we show that only cardiomyocyte expression protects against IRI (45 min ischemia followed by reperfusion over 24 h). Infarct size was also limited after ischemia-reperfusion in mice with cardiomyocyte hβ3AR overexpression on top of endogenous β3AR expression. hβ3AR overexpression in these mice reduced IRI-induced cardiac fibrosis and improved long-term left ventricular systolic function. Cardiomyocyte-specific β3AR overexpression resulted in a baseline remodeling of the mitochondrial network, characterized by upregulated mitochondrial biogenesis and a downregulation of mitochondrial quality control (mitophagy), resulting in elevated numbers of small mitochondria with a depressed capacity for the generation of reactive oxygen species but improved capacity for ATP generation. These processes precondition cardiomyocyte mitochondria to be more resistant to IRI. Upon reperfusion, hearts with hβ3AR overexpression display a restoration in the mitochondrial quality control and a rapid activation of antioxidant responses. Strong protection against IRI was also observed in mice infected with an adeno-associated virus (AAV) encoding hβ3AR under a cardiomyocyte-specific promoter. These results confirm the translational potential of increased cardiomyocyte β3AR expression, achieved either naturally through exercise or artificially through gene therapy approaches, to precondition the cardiomyocyte mitochondrial network to withstand future insults.engVoRhttp://creativecommons.org/licenses/by/4.0/Beta adrenergic receptorIschemia–reperfusion injuryMitochondriaMitophagyPreconditioningAttribution 4.0 International391346631195773-794Basic Research in Cardiologyopen access