Browsing by Author "Aguirre, Francisco"

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    Role of the ubiquitin-proteasome system in the sarcopenic-like phenotype induced by CCL5/RANTES
    (2024) Conejeros-Lillo, Sabrina; Aguirre, Francisco; Cabrera, Daniel; Simon, Felipe; Penailillo, Luis; Cabello-Verrugio, Claudio
    Sarcopenia is characterized by reduced muscle strength and mass, and a decline in muscle fiber diameter and amount of sarcomeric proteins. Sarcopenia involves the activation of the ubiquitinproteasome system (UPS). MuRF-1 and atrogin-1 are E3 ubiquitin ligases belonging to UPS, leading to proteolysis mediated by the PSMB 5, 6, and 7 subunits of 20S proteasome. CCL5/RANTES induces a sarcopenic-like effect in muscle cells. The present work explored the impact of CCL5 on UPS components and the influence of UPS on its sarcopenic-like effect. We demonstrated that CCL5 increased MuRF-1 and atrogin-1 protein levels and mRNA levels of subunits PSMB 5, 6, and 7. We used the MG132 inhibitor to elucidate the role of the 20S proteasome in the CCL5-induced sarcopenic-like effect. This inhibitor prevented the decrease in troponin and MHC protein levels and partially stopped the reduction in the diameter of singleisolated flexor digitorum brevis (FDB) muscle fibers induced by CCL5. These findings indicate that CCL5 actively modulates the UPS. Moreover, our results show the direct participation of UPS in the sarcopenic-like phenotype induced by CCL5.
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    Sarcopenia in a mice model of chronic liver disease: role of the ubiquitin–proteasome system and oxidative stress
    (2018) Campos, Fabián; Abrigo, Johanna; Aguirre, Francisco; Garcés, Bruno; Arrese Jiménez, Marco; Karpen, Saúl; Cabrera, Daniel; Andía Kohnenkampf, Marcelo Edgardo; Simon, Felipe; Cabello Verrugio, Claudio Alejandro
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    Survival rates in the world's southernmost forest bird community
    (2023) Sandvig, Erik M.; Quilodran, Claudio S.; Altamirano, Tomas A.; Aguirre, Francisco; Barroso, Omar; de Aguilar, Juan Rivero; Schaub, Michael; Kery, Marc; Vasquez, Rodrigo A.; Rozzi, Ricardo
    The Magellanic sub-Antarctic Forest is home to the world's southernmost avian community and is the only Southern Hemisphere analogue to Northern Hemisphere temperate forests at this latitude. This region is considered among the few remaining pristine areas of the world, and shifts in environmental conditions are predominantly driven by climate variability. Thus, understanding climate-driven demographic processes is critical for addressing conservation issues in this system under future climate change scenarios. Here, we describe annual survival patterns and their association with climate variables using a 20-year mark-recapture data set of five forest bird species in the Cape Horn Biosphere Reserve. We develop a multispecies hierarchical survival model to jointly explore age-dependent survival probabilities at the community and species levels in a group of five forest passerines. At the community level, we assess the association of migratory behavior and body size with survival, and at the species level, we investigate the influence of local and regional climatic variables on temporal variations of survival. We found a positive effect of precipitation and a negative effect of El Nino Southern Oscillation on juvenile survival in the white-crested Elaenia and a consistent but uncertain negative effect of temperature on survival in juveniles and 80% of adults. We found only a weak association of climate variables with survival across species in the community and no temporal trends in survival for any of the species in either age class, highlighting apparent stability in these high austral latitude forests. Finally, our findings provide an important resource of survival probabilities, a necessary input for assessing potential impacts of global climate change in this unique region of the world.