Extracellular Vesicles Released after Doxorubicin Treatment in Rats Protect Cardiomyocytes from Oxidative Damage and Induce Pro-Inflammatory Gene Expression in Macrophages

Doxorubicin (DOXO)-induced cardiomyopathy (DIC) is a lethal complication in cancer patients. Major mechanisms of DIC involve oxidative stress in cardiomyocytes and hyperactivated immune response. Extracellular vesicles (EVs) mediate cell–cell communication during oxidative stress. However, functions of circulating EVs released after chronic DOXO exposure on cardiomyocytes and immune cells are still obscured. Herein, we developed a DIC in vivo model using male Wistar rats injected with 3 mg/kg DOXO for 6 doses within 30 days (18 mg/kg cumulative dose). One month after the last injection, the rats developed cardiotoxicity evidenced by increased BCL2-associated X protein and cleaved caspase-3 in heart tissues, along with N-terminal pro B-type natriuretic peptide in sera. Serum EVs were isolated by size exclusion chromatography. EV functions on H9c2 cardiomyocytes and NR8383 macrophages were evaluated. EVs from DOXO-treated rats (DOXO_EVs) attenuated ROS production via increased glutathione peroxidase-1 and catalase gene expression, and reduced hydrogen peroxide-induced cell death in cardiomyocytes. In contrast, DOXO_EVs induced ROS production, interleukin-6, and tumor necrosis factor-alpha, while suppressing arginase-1 gene expression in macrophages. These results suggested the pleiotropic roles of EVs against DIC, which highlight the potential role of EV-based therapy for DIC with a concern of its adverse effect on immune response

Synaptosome Bioenergetics and Calcium Handling: Aging Response

Synaptic function and the role of mitochondria inside nerve terminals can be studied by the isolation of an enriched fraction of synaptosomes, which consist in nerve ending particles that are formed during homogenization of brain tissue. Different procedures have been described for the isolation of an enriched fraction of synaptosomes, most of them based on the use of gradients. Neuronal function seems to be critically dependent on the energy provided by mitochondrial respiration. The determination of bioenergetic parameters such as mitochondrial membrane potential, respiratory rates, ATP content and mitochondrial Ca2+ uptake in synaptosomal preparations can provide useful information to analyze the contribution of mitochondrial function to the efficiency of neurotransmission.Synaptic nerve terminals are constantly exposed to extensive Ca2+ fluxes. At the presynaptic terminal, the recovery from calcium oscillations critically depends on the proper mitochondrial function to generate ATP and buffer Ca2+ transients together with an efficient endoplasmic reticulum function.The differential characteristics of synaptic and non-synaptic mitochondria in terms of bioenergetics and free radical production, as well as the response to aging are discussed.Fil: Lores Arnaiz, Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: Rodriguez, Georgina Emma. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: Karadayian, Analia Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: Bustamante, Juanita. Universidad Abierta Interamericana; Argentin