Browsing by Author "Leal Reyes, Nancy Valeria"

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    c-Abl Inhibition Activates TFEB and Promotes Cellular Clearance in a Lysosomal Disorder
    (2020) Contreras, P. S.; Tapia Ossa, Pablo José; González Hódar, Lila Alejandra; Peluso, I.; Soldati, C.; Valls Jiménez, Cristián; Balboa Castillo, Elisa Ivana; Castro Alonso, Juan Cristóbal; Leal Reyes, Nancy Valeria; Zanlungo Matsuhiro, Silvana; Napolitano, G.; Matarese, M.; Heras, M. L.; Martinez, A.; Platt, F. M.; Sobota, A.; Winter, D.; Klein, A. D.; Medina, D. L.; Ballabio, A.; Alvarez, A. R.
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    c-Abl Phosphorylates MFN2 to Regulate Mitochondrial Morphology in Cells under Endoplasmic Reticulum and Oxidative Stress, Impacting Cell Survival and Neurodegeneration
    (De Gruyter, 2023) Martinez Saavedra, Alexis; Lamaizon Muñoz, Cristián Nicolás; Valls Jimenez, Cristián; Llambi, Fabien; Leal Reyes, Nancy Valeria; Fitzgerald, Patrick; Guy, Cliff; Kaminsk,i Marcin M.; Inestrosa Cantin, Nibaldo; van Zundert, Brigitte; Cancino, Gonzalo; Dulcey, Andrés E.; Zanlungo Matsuhiro, Silvana; Marugan, Juan J.; Hetz, Claudio; Green, Douglas R.; Alvarez Rojas, Alejandra
    The endoplasmic reticulum is a subcellular organelle key in the control of synthesis, folding, and sorting of proteins. Under endoplasmic reticulum stress, an adaptative unfolded protein response is activated; however, if this activation is prolonged, cells can undergo cell death, in part due to oxidative stress and mitochondrial fragmentation. Here, we report that endoplasmic reticulum stress activates c-Abl tyrosine kinase, inducing its translocation to mitochondria. We found that endoplasmic reticulum stress-activated c-Abl interacts with and phosphorylates the mitochondrial fusion protein MFN2, resulting in mitochondrial fragmentation and apoptosis. Moreover, the pharmacological or genetic inhibition of c-Abl prevents MFN2 phosphorylation, mitochondrial fragmentation, and apoptosis in cells under endoplasmic reticulum stress. Finally, in the amyotrophic lateral sclerosis mouse model, where endoplasmic reticulum and oxidative stress has been linked to neuronal cell death, we demonstrated that the administration of c-Abl inhibitor neurotinib delays the onset of symptoms. Our results uncovered a function of c-Abl in the crosstalk between endoplasmic reticulum stress and mitochondrial dynamics via MFN2 phosphorylation.
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    c-Abl Phosphorylates MFN2 to Regulate Mitochondrial Morphology in Cells under Endoplasmic Reticulum and Oxidative Stress, Impacting Cell Survival and Neurodegeneration
    (MDPI, 2023) Martinez Saavedra, Alexis; Lamaizon Muñoz, Cristián Nicolás; Valls Jimenez, Cristián; Llambi, Fabien; Leal Reyes, Nancy Valeria; Fitzgerald, Patrick; Guy, Cliff; Kaminsk,i Marcin M.; Inestrosa Cantin, Nibaldo; van Zundert, Brigitte; Cancino, Gonzalo; Dulcey, Andrés E.; Zanlungo Matsuhiro, Silvana; Marugan, Juan J.; Hetz, Claudio; Green, Douglas R.; Alvarez Rojas, Alejandra
    The endoplasmic reticulum is a subcellular organelle key in the control of synthesis, folding, and sorting of proteins. Under endoplasmic reticulum stress, an adaptative unfolded protein response is activated; however, if this activation is prolonged, cells can undergo cell death, in part due to oxidative stress and mitochondrial fragmentation. Here, we report that endoplasmic reticulum stress activates c-Abl tyrosine kinase, inducing its translocation to mitochondria. We found that endoplasmic reticulum stress-activated c-Abl interacts with and phosphorylates the mitochondrial fusion protein MFN2, resulting in mitochondrial fragmentation and apoptosis. Moreover, the pharmacological or genetic inhibition of c-Abl prevents MFN2 phosphorylation, mitochondrial fragmentation, and apoptosis in cells under endoplasmic reticulum stress. Finally, in the amyotrophic lateral sclerosis mouse model, where endoplasmic reticulum and oxidative stress has been linked to neuronal cell death, we demonstrated that the administration of c-Abl inhibitor neurotinib delays the onset of symptoms. Our results uncovered a function of c-Abl in the crosstalk between endoplasmic reticulum stress and mitochondrial dynamics via MFN2 phosphorylation.
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    Lysosomal vitamin E accumulation in Niemann-Pick type C disease
    (2011) Yévenes, Luz Fernanda; Klein Posternack, Andrés David; Castro, Juan Francisco; Marín Marín, Tamara Alejandra; Leal Reyes, Nancy Valeria; Leighton Puga, Federico; Álvarez, Alejandra R.; Zanlungo Matsuhiro, Silvana
    Niemann-Pick C disease (NPC) is a neuro-visceral lysosomal storage disorder mainly caused by genetic defects in the NPC1 gene. As a result of loss of NPC1 function large quantities of free cholesterol and other lipids accumulate within late endosomes and lysosomes. In NPC livers and brains, the buildup of lipids correlates with oxidative damage; however the molecular mechanisms that trigger it remain unknown. Here we study potential alterations in vitamin E (α-tocopherol, α-TOH), the most potent endogenous antioxidant, in liver tissue and neurons from NPC1 mice. We found increased levels of α-TOH in NPC cells. We observed accumulation and entrapment of α-TOH in NPC neurons, mainly in the late endocytic pathway. Accordingly, α-TOH levels were increased in cerebellum of NPC1 mice. Also, we found decreased mRNA levels of the α-TOH transporter, α-Tocopherol Transfer Protein (α-TTP), in the cerebellum of NPC1 mice. Finally, by subcellular fractionation studies we detected a significant increase in the hepatic α-TOH content in purified lysosomes from NPC1 mice. In conclusion, these results suggest that NPC cells cannot transport vitamin E correctly leading to α-TOH buildup in the endosomal/lysosomal system. This may result in a decreased bioavailability and impaired antioxidant function of vitamin E in NPC, contributing to the disease pathogenesis.