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Palmitic acid reduces the autophagic flux in hypothalamic neurons by impairing autophagosome-lysosome fusion and endolysosomal dynamics
Journal article   Open access

Palmitic acid reduces the autophagic flux in hypothalamic neurons by impairing autophagosome-lysosome fusion and endolysosomal dynamics

María Paz Hernández-Cáceres, Karina Cereceda, Sergio Hernández, Ying Li, Carla Narro, Patricia Rivera, Patricio Silva, Yenniffer Ávalos, Claudia Jara, Paulina Burgos, …
Molecular & cellular oncology, v 7(5), pp 1789418-1789418
02 Sep 2020
PMID: 32944643
url
https://www.tandfonline.com/doi/pdf/10.1080/23723556.2020.1789418?needAccess=trueView
Published, Version of Record (VoR) Open
url
https://doi.org/10.1080/23723556.2020.1789418View
Published, Version of Record (VoR) Open

Abstract

autophagy central nervous system electron microscopy high-fat diet hypothalamic neuronal cells lysosomes obesity-associated cancers Palmitic acid Rab7
High-fat diet (HFD)-induced obesity is associated with increased cancer risk. Long-term feeding with HFD increases the concentration of the saturated fatty acid palmitic acid (PA) in the hypothalamus. We previously showed that, in hypothalamic neuronal cells, exposure to PA inhibits the autophagic flux, which is the whole autophagic process from the synthesis of the autophagosomes, up to their lysosomal fusion and degradation. However, the mechanism by which PA impairs autophagy in hypothalamic neurons remains unknown. Here, we show that PA-mediated reduction of the autophagic flux is not caused by lysosomal dysfunction, as PA treatment does not impair lysosomal pH or the activity of cathepsin B.Instead, PA dysregulates autophagy by reducing autophagosome-lysosome fusion, which correlates with the swelling of endolysosomal compartments that show areduction in their dynamics. Finally, because lysosomes undergo constant dynamic regulation by the small Rab7 GTPase, we investigated the effect of PA treatment on its activity. Interestingly, we found PA treatment altered the activity of Rab7. Altogether, these results unveil the cellular process by which PA exposure impairs the autophagic flux. As impaired autophagy in hypothalamic neurons promotes obesity, and balanced autophagy is required to inhibit malignant transformation, this could affect tumor initiation, progression, and/or response to therapy of obesity-related cancers.

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Web of Science research areas
Oncology
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