RESUMEN
Although the mTOR-4E-BP1 signaling pathway is implicated in aging and aging-related disorders, the role of 4E-BP1 in regulating human stem cell homeostasis remains largely unknown. Here, we report that the expression of 4E-BP1 decreases along with the senescence of human mesenchymal stem cells (hMSCs). Genetic inactivation of 4E-BP1 in hMSCs compromises mitochondrial respiration, increases mitochondrial reactive oxygen species (ROS) production, and accelerates cellular senescence. Mechanistically, the absence of 4E-BP1 destabilizes proteins in mitochondrial respiration complexes, especially several key subunits of complex III including UQCRC2. Ectopic expression of 4E-BP1 attenuates mitochondrial abnormalities and alleviates cellular senescence in 4E-BP1-deficient hMSCs as well as in physiologically aged hMSCs. These f indings together demonstrate that 4E-BP1 functions as a geroprotector to mitigate human stem cell senescence and maintain mitochondrial homeostasis, particularly for the mitochondrial respiration complex III, thus providing a new potential target to counteract human stem cell senescence.
Asunto(s)
Humanos , Células Madre Mesenquimatosas/fisiología , Senescencia Celular , Homeostasis , Proteínas de Ciclo Celular/metabolismo , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Mitocondrias/metabolismo , Complejo III de Transporte de Electrones/metabolismo , Células CultivadasRESUMEN
La fiebre chikungunya (CHIK) es una enfermedad viral transmitida al ser humano por el mismo vector del dengue, el mosquito Aedes. Además de fiebre y fuertes dolores articulares, produce otros síntomas como mialgias, cefalea, náuseas, cansancio y exantema. No tiene tratamiento específico; el manejo terapéutico de los pacientes se enfoca en el alivio de los síntomas. Históricamente se han reportado brotes de grandes proporciones; incluso desde 2010 se llegó a considerar como una potencial epidemia emergente. En 2013 se introdujo a las islas del Caribe y recientemente se ha reportado en el continente americano. En este trabajo se describe el primer caso confirmado de chikungunya en México, en el municipio de Tlajomulco de Zúñiga, Jalisco, en mayo de 2014, importado de la isla Antigua y Barbuda, en el Caribe, por una mujer de 39 años de edad.
Chikungunya fever (CHIK) is a viral disease transmitted to human beings by the same vector as dengue -the Aedes mosquito. Besides fever and severe pain in the joints, it produces other symptoms such as myalgias, headache, nausea, fatigue and exanthema. There is no specific treatment for it; the therapeutic management of patients focuses on symptom relief. Historically, outbreaks of large proportions have been reported; even since 2010 it was considered to be a potential emerging epidemic. In 2013 it was introduced into the islands of the Caribbean, and it has recently been reported in the American continent. This paper describes the first confirmed case of chikungunya in Mexico -in the municipality of Tlajomulco de Zúñiga, Jalisco, in May, 2014-, which was imported from the Caribbean island of Antigua and Barbuda by a 39 year-old woman.