Sabio lab

at the CNIC

Tag: lipid metabolism

Hypothalamic AMPK-ER stress-JNK1 axis mediates the central actions of thyroid hormones on energy balance

Noelia Martínez-Sánchez, Patricia Seoane-Collazo, Cristina Contreras, Luis Varela, Joan Villarroya, Eva Rial-Pensado, Xabier Buqué, Igor Aurrekoetxea, Teresa C. Delgado, Rafael Vázquez-Martínez, Ismael González-García, Juan Roa, Andrew J. Whittle, Beatriz Gomez-Santos, Vidya Velagapudi, Y.C. Loraine Tung, Donald A. Morgan, Peter J. Voshol, Pablo B. Martínez de Morentin, Tania López-González, Laura Liñares-Pose, Francisco Gonzalez, Krishna Chatterjee, Tomás Sobrino, Gema Medina-Gómez, Roger J. Davis, Núria Casals, Matej Orešič, Anthony P. Coll, Antonio Vidal-Puig, Jens Mittag, Manuel Tena-Sempere, María M. Malagón, Carlos Diéguez, María Luz Martínez-Chantar, Patricia Aspichueta, Kamal Rahmouni, Rubén Nogueiras, Guadalupe Sabio, Francesc Villarroya & Miguel López.

Pathway proposed to modulate lipid metabolism in liverThyroid hormones (THs) act in the brain to modulate energy balance. We show that central triiodothyronine (T3) regulates de novo lipogenesis in liver and lipid oxidation in brown adipose tissue (BAT) through the parasympathetic (PSNS) and sympathetic nervous system (SNS), respectively. Central T3 promotes hepatic lipogenesis with parallel stimulation of the thermogenic program in BAT.

The action of T3 depends on AMP-activated protein kinase (AMPK)-induced regulation of two signaling pathways in the ventromedial nucleus of the hypothalamus (VMH): decreased ceramide-induced endoplasmic reticulum (ER) stress, which promotes BAT thermogenesis, and increased c-Jun N-terminal kinase (JNK) activation, which controls hepatic lipid metabolism. Of note, ablation of AMPKα1 in steroidogenic factor 1 (SF1) neurons of the VMH fully recapitulated the effect of central T3, pointing to this population in mediating the effect of central THs on metabolism.

Overall, these findings uncover the underlying pathways through which central T3 modulates peripheral metabolism.

Hepatic p63 regulates steatosis via IKKβ/ER stress

Begoña Porteiro, Marcos F. Fondevila, Teresa C. Delgado, Cristina Iglesias, Monica Imbernon, Paula Iruzubieta, Javier Crespo, Amaia Zabala-Letona, Johan Fernø, Bárbara González-Terán, Nuria Matesanz, Lourdes Hernández-Cosido, Miguel Marcos, Sulay Tovar, Anxo Vidal, Julia Sánchez-Ceinos, Maria M. Malagon, Celia Pombo, Juan Zalvide, Arkaitz Carracedo, Xabier Buque, Carlos Dieguez, Guadalupe Sabio, Miguel López, Patricia Aspichueta, María L. Martínez-Chantar & Ruben Nogueiras.

Pathway proposed to modulate lipid metabolism in liverp53 family members control several metabolic and cellular functions. The p53 ortholog p63 modulates cellular adaptations to stress and has a major role in cell maintenance and proliferation.

Here we show that p63 regulates hepatic lipid metabolism. Mice with liver-specific p53 deletion develop steatosis and show increased levels of p63. Down-regulation of p63 attenuates liver steatosis in p53 knockout mice and in diet-induced obese mice, whereas the activation of p63 induces lipid accumulation. Hepatic overexpression of N-terminal transactivation domain TAp63 induces liver steatosis through IKKβ activation and the induction of ER stress, the inhibition of which rescues the liver functions. Expression of TAp63, IKKβ and XBP1s is also increased in livers of obese patients with NAFLD. In cultured human hepatocytes, TAp63 inhibition protects against oleic acid-induced lipid accumulation, whereas TAp63 overexpression promotes lipid storage, an effect reversible by IKKβ silencing.

Our findings indicate an unexpected role of the p63/IKKβ/ER stress pathway in lipid metabolism and liver disease.

p38γ and p38δ reprogram liver metabolism by modulating neutrophil infiltration

Bárbara González‐Terán, Nuria Matesanz, Ivana Nikolic, María Angeles Verdugo, Vinatha Sreeramkumar, Lourdes Hernández‐Cosido, Alfonso Mora, Georgiana Crainiciuc, María Laura Sáiz, Edgar Bernardo, Luis Leiva‐Vega, Elena Rodríguez, Victor Bondía, Jorge L Torres, Sonia Perez‐Sieira, Luis Ortega, Ana Cuenda, Francisco Sanchez‐Madrid, Rubén Nogueiras, Andrés Hidalgo, Miguel Marcos & Guadalupe Sabio.

Non‐alcoholic fatty liver disease (NAFLD) is a major health problem and the main cause of liver disease in Western countries. Although NAFLD is strongly associated with obesity and insulin resistance, its pathogenesis remains poorly understood.

The disease begins with an excessive accumulation of triglycerides in the liver, which stimulates an inflammatory response. Alternative p38 mitogen‐activated kinases (p38γ and p38δ) have been shown to contribute to inflammation in different diseases. Here we demonstrate that p38δ is elevated in livers of obese patients with NAFLD and that mice lacking p38γ/δ in myeloid cells are resistant to diet‐induced fatty liver, hepatic triglyceride accumulation and glucose intolerance. This protective effect is due to defective migration of p38γ/δ‐deficient neutrophils to the damaged liver.

We further show that neutrophil infiltration in wild‐type mice contributes to steatosis development by means of inflammation and liver metabolic changes. Therefore, p38γ and p38δ in myeloid cells provide a potential target for NAFLD therapy.

© 2017 Sabio lab

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