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Loss of skeletal muscle mass and function is a hallmark of aging. This phenomenon has been related to a dysregulation of mitochondrial function and proteostasis. Calorie restriction (CR) has been demonstrated to delay aging and preserve function until late in life, particularly in muscle. Recently, we reported the type of dietary fat plays an important role in determining life span extension with 40% CR in male mice. In these conditions, lard fed mice showed an increased longevity compared to mice fed soybean or fish oils. In this article, we analyze the effect of 40% CR on muscle mitochondrial mass, autophagy, and mitochondrial dynamics markers in mice fed these diets. In CR fed animals, lard preserved muscle fibers structure, mitochondrial ultrastructure, and fission/fusion dynamics and autophagy, not only compared to control animals, but also compared with CR mice fed soybean and fish oils as dietary fat. We focus our discussion on dietary fatty acid saturation degree as an essential predictor of life span extension in CR mice., This study was supported by National Institutes of Health grant 1R01AG028125 (to J.J.R., P.N. and J.M.V.); Spanish Ministerio de Economía y Competitividad BFU2015-64630-R cofinanced with EU FEDER funds (to J.M.V.); Spanish Junta de Andalucía (Proyectos Internacionales grant and BIO-276 to J.M.V.; BIO-177 to P.N.); and Universidad de Córdoba. E.G.C. and J.A.L.D. were supported by FPU contracts from the Spanish Ministerio de Educación, Cultura y Deporte. H.K. was funded by the Spanish Agencia Española de Cooperación Internacional al Desarrollo. Rd.C. is supported by the Intramural Research Program of the National Institute on Aging.

In this work it is analyzed the effect of aging and its possible preventionby calorie restriction (CR) in liver and skeletal muscle from mice. These organswere selected as models of mitotic and post-mitotic tissues, respectively.Furthermore, the effect of dietary fat under CR was also investigated. For thispurpose, animals submitted to CR were separated into three CR groups withsoybean oil (high in ω−6 polyunsaturated fatty acids), fish oil (with a highcontent of polyunsaturated ω-3 fatty acids) and lard (rich in saturated andmonounsaturated fatty acids). Soybean oil was the fat source in control adlibitum fed animals. After 6 and 18 months of CR, animals were killed anddifferent morphological and functional parameters of both organs were studied.In liver, our results show that CR induced changes in hepatocyte andmitochondrial size, in the volume fraction occupied by mitochondria, and in thenumber of mitochondria per hepatocyte. Also, mean number of mitochondrialcristae and lengths were significantly higher in all CR groups compared withcontrols. CR had no remarkable effects on the expression levels of fission (Fis1and Drp1) and fusion (Mfn1, Mfn2 and OPA1) protein markers after 18 monthsof CR. However, considerable differences in many of these parameters werefound when comparing the CR groups. On the other hand, aging, CR and fatsource are all factors that may influence apoptotic signaling in liver. For thisreason the combined effect of these factors on a number of apoptosisregulators and effectors were studied as well. An age-linked increase in themitochondrial apoptotic pathway was detected with CR, including a decrease inBcl-2/Bax ratio, an enhanced release of cytochrome c to the cytosol and highercaspase-9 activity. Apoptotic index (DNA fragmentation) and mean nuclear areawere increased in aged animals with the exception of calorie-restricted mice feda lard-based fat source.In skeletal muscle, 6 and 18 months of CR partially prevented thedecreased size of red and white fibers observed in aged control mice. At theultrastructural level, mean area of myofibrils and planimetric parameters ofsubsarcolemmal and intermyofibrilar mitochondria also changed during agingand in the different groups of CR and similar results were obtained when theexpression levels of protein related to mitochondrial fission, fusion and function(Sirt3 and VDAC) were analyzed..., En este trabajo se estudia el efecto del envejecimiento y su posibleprevención mediante restricción calórica (RC) en hígado y músculo esqueléticode ratón. Dichos órganos fueron elegidos como modelo de tejidos mitótico ypostmitótico respectivamente. Asímismo se investigó el efecto de la grasa de ladieta. Para ello, los animales sometidos a RC se separaron en tres grupos quefueron alimentados con diferentes fuentes de grasa: aceite de soja (rico enácidos grasos poliinsaturados tipo ω−6), aceite de pescado (rico en en ácidosgrasos poliinsaturados tipo ω−3) y manteca (rica en ácidos grasos saturados ymonoinsaturados). La fuente de grasa en los animals control alimentados adlibitum fue aceite de soja. Tras 6 y 18 meses en dichas condiciones, losanimales fueron sacrificados y se analizaron diversos parámetros morfológicosy funcionales de ambos órganos.En hígado, los resultados mostraron que la RC indujo cambios en eltamaño de hepatocitos y las mitocondrias así como en el número y la fracciónde volumen ocupado por mitocondrias en el hepatocito. De igual forma, ennúmero medio de crestas mitocondriales y su longitud aumentaron de formaconsiderable en todos los grupos de RC en comparación con los animalescontrol. La RC no tuve efectos considerables en los niveles de expresión deproteínas relacionadas con la fisión (Fis1 y Drp1) y fusión mitocondrial (Mfn1,Mfn2 y OPA1) tras 18 meses de RC. Sin embargo, éstas aparecieron alcomparar entre sí los distintos grupos de RC. Por otra parte, el envejecimiento,la RC y la fuente de grasa son factores que pueden influir en la señalizaciónapoptótica en hígado. Por dicha razón se estudió el efecto combinado de esosfactores sobre diversos reguladores y efectores de la apoptosis, encontrándoseun incremento dependiente de la edad en la ruta mitocondrial apoptótica en losanimales sometidos a RC entre los que se incluyen disminución de la relaciónBcl-2/Bax, aumento de la liberación de citocromo c al citosol e incremento en laactividad caspasa-9. El índice apoptótico (fragmentación de DNA) y el áreamedia nuclear aumentaron en los animales más envejecidos con la excepciónde los que fueron alimentados con manteca y en condiciones de RC.En músculo esquelético, 6 y 18 meses de RC previnieron en parte ladisminución del tamaño de fibras rojas y blancas que se había observado enlos ratones control. A nivel ultraestructural, el área media de las fibrillas y los...

Resumen del póster presentado al XV Congreso de la Sociedad Española de Biología Celular celebrado en Madrid del 17 al 19 de noviembre de 2013.

Resumen del trabajo presentado al XIV Congresos de la Sociedad Española de Biología Celular, celebrado en Málaga del 12 al 15 de diciembre de 2011.

Resumen del póster presentado al XXXIII Congreso de la Sociedad Española de Bioquímica y Biología Molecular celebrado en Córdoba del 14 al 17 de septiembre de 2010., La reducción en la carga calórica de la dieta en mamíferos (restricción calórica) altera de manera drástica su metabolismo, siendo el más llamativo y conocido de sus efectos la extensión de la longevidad. Sin embargo, es aún necesario un análisis más profundo de sus mecanismos de actuación. Nuestro estudio pretende analizar el efecto combinado de una restricción calórica del 40% con la introducción de variaciones en el origen del componente graso de la dieta (distinguiendo entre grasas altamente saturadas, ricas en ácido linoleico y ricas en ácidos grasos poliinsaturadas n-3). Sobre muestras de músculo esquelético de ratones sometidos a dichas dietas, hemos observado variaciones en la expresión de la subunidad a1 de la sodio/potasio-ATPasa, un complejo oligomérico de membrana responsable de la mayor parte del gasto energético basal de la célula. Asimismo, un estudio estructural y morfométrico sobre estas mismas muestras indica la existencia de alteraciones en las características de las fibras musculares. Así, los animales no sometidos a restricción calórica muestran un menor desarrollo de las fibras musculares esqueléticas (determinado sobre el músculo gastrocnemio), mientras que el resto de los animales con distintas fuentes de materia grasa pero sometidos a restricción calórica, muestran un aumento significativo del grosor de la fibra muscular. Estos cambios pueden llegar a suponer hasta un 10% de incremento. Estos datos, tomados en su conjunto, indican la existencia de un proceso adaptativo metabólico que implica cambios en la estructura celular y en los procesos bioquímicos., Junta de Andalucía, National Institutes of Health, Ministerio de Educación, Agencia Española de Cooperación Internacional.

Aging is a complex phenomenon involving functional decline in multiple physiological systems. We undertook a comparative analysis of skeletal muscle from four different species, i.e. mice, rats, rhesus monkeys, and humans, at three different representative stages during their lifespan (young, middle, and old) to identify pathways that modulate function and healthspan. Gene expression profiling and computational analysis revealed that pathway complexity increases from mice to humans, and as mammals age, there is predominantly an upregulation of pathways in all species. Two downregulated pathways, the electron transport chain and oxidative phosphorylation, were common among all four species in response to aging. Quantitative PCR, biochemical analysis, mitochondrial DNA measurements, and electron microscopy revealed a conserved age-dependent decrease in mitochondrial content, and a reduction in oxidative phosphorylation complexes in monkeys and humans. Western blot analysis of key proteins in mitochondrial biogenesis discovered that (i) an imbalance toward mitochondrial fusion occurs in aged skeletal muscle and (ii) mitophagy is not overtly affected, presumably leading to the observed accumulation of abnormally large, damaged mitochondria with age. Select transcript expression analysis uncovered that the skeletal inflammatory profile differentially increases with age, but is most pronounced in humans, while increased oxidative stress (as assessed by protein carbonyl adducts and 4-hydroxynonenal) is common among all species. Expression studies also found that there is unique dysregulation of the nutrient sensing pathways among the different species with age. The identification of conserved pathways indicates common molecular mechanisms intrinsic to health and lifespan, whereas the recognition of species-specific pathways emphasizes the importance of human studies for devising optimal therapeutic modalities to slow the aging process., Conserved and unique aging regulatory pathways Aging is a complex phenomenon involving functional declines in multiple physiological systems with the passage of time. Focusing on skeletal muscle, a group of international scientists identified pathways involved in healthspan and by determining global gene expression profiles across species they exposed common mechanisms fundamental to the aging process. Their experimental design involved comparative analysis of mice, rats, rhesus monkeys and humans, targeting three key time points during their respective lifespans. Pathways related to oxidative stress, inflammation and nutrient signaling, which function collectively to affect the quality and status of mitochondria, emerged across all species in an age-influenced manner. The identification of conserved pathways reveals molecular mechanisms intrinsic to health and survival, whereas the unveiling of species-specific pathways emphasizes the importance of human studies for devising optimal therapeutic modalities to slow the aging process.