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Author: Sabio lab (Page 2 of 58)

Absence of MCJ/DnaJC15 promotes brown adipose tissue thermogenesis

Beatriz Cicuéndez, Alfonso Mora, Juan Antonio López, Andrea Curtabbi, Javier Pérez-García, Begoña Porteiro, Daniel Jimenez-Blasco, Pedro Latorre-Muro, Paula Vo, Madison Jerome, Beatriz Gómez-Santos, Rafael Romero-Becerra, Magdalena Leiva, Elena Rodríguez, Marta León, Luis Leiva-Vega, Noemi Gómez-Lado, Jorge L. Torres, Lourdes Hernández-Cosido, Pablo Aguiar, Miguel Marcos, Martin Jastroch, Andreas Daiber, Patricia Aspichueta, Juan Pedro Bolaños, Jessica B. Spinelli, Pere Puigserver, José Antonio Enriquez, Jesús Vázquez, Cintia Folgueira & Guadalupe Sabio.

Obesity poses a global health challenge, demanding a deeper understanding of adipose tissue (AT) and its mitochondria. This study describes the role of the mitochondrial protein Methylation-controlled J protein (MCJ/DnaJC15) in orchestrating brown adipose tissue (BAT) thermogenesis.

Mitochondia from brown fat (Image: Beatriz Cicuéndez).

Here we show how MCJ expression decreases during obesity, as evident in human and mouse adipose tissue samples. MCJKO mice, even without UCP1, a fundamental thermogenic protein, exhibit elevated BAT thermogenesis. Electron microscopy unveils changes in mitochondrial morphology resembling BAT activation. Proteomic analysis confirms these findings and suggests involvement of the eIF2α mediated stress response. The pivotal role of eIF2α is scrutinized by in vivo CRISPR deletion of eIF2α in MCJKO mice, abrogating thermogenesis.

These findings uncover the importance of MCJ as a regulator of BAT thermogenesis, presenting it as a promising target for obesity therapy.

Plasma membrane remodeling determines adipocyte expansion and mechanical adaptability

María C M Aboy-Pardal, Marta C Guadamillas, Carlos R Guerrero, Mauro Català-Montoro, Mónica Toledano-Donado, Sara Terrés-Domínguez, Dácil M Pavón, Víctor Jiménez-Jiménez, Daniel Jimenez-Carretero, Moreno Zamai, Cintia Folgueira, Ana Cerezo, Fidel-Nicolás Lolo, Rubén Nogueiras, Guadalupe Sabio, Miguel Sánchez-Álvarez, Asier Echarri, Ricardo Garcia & Miguel A Del Pozo.

Adipocytes expand massively to accommodate excess energy stores and protect the organism from lipotoxicity. Adipose tissue expandability is at the center of disorders such as obesity and lipodystrophy; however, little is known about the relevance of adipocyte biomechanics on the etiology of these conditions.

Adipocyte classification based on the existence (magenta, asterisks) or absence (yellow, triangles) of surrounding collagen.

Here, we show in male mice in vivo that the adipocyte plasma membrane undergoes caveolar domain reorganization upon lipid droplet expansion. As the lipid droplet grows, caveolae disassemble to release their membrane reservoir and increase cell surface area, and transfer specific caveolar components to the LD surface. Adipose tissue null for caveolae is stiffer, shows compromised deformability, and is prone to rupture under mechanical compression. Mechanistically, phosphoacceptor Cav1 Tyr14 is required for caveolae disassembly: adipocytes bearing a Tyr14Phe mutation at this residue are stiffer and smaller, leading to decreased adiposity in vivo; exhibit deficient transfer of Cav1 and EHD2 to the LD surface, and show distinct Cav1 molecular dynamics and tension adaptation.

These results indicate that Cav1 phosphoregulation modulates caveolar dynamics as a relevant component of the homeostatic mechanoadaptation of the differentiated adipocyte.

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