Referencia

Hepatology. 2011 Dec;54(6):1975-86

Autores

Ainara Cano, Xabier Buqué, Maite Martínez-Uña, Igor Aurrekoetxea, Ariane Menor, Juan Luis García-Rodríguez2, Shelly Lu, José María Mato, Begoña Ochoa y Patricia Aspichueta

Resumen

Very low-density lipoprotein (VLDL) secretion provides a mechanism to export triglycerides (TG) from the liver to peripheral tissues, maintaining lipid homeostasis. In nonalcoholic fatty liver disease (NAFLD), VLDL secretion disturbances are unclear. Methionine adenosyltransferase (MAT) is responsible for S-adenosylmethionine (SAMe) synthesis and MAT I and III are the products of the MAT1A gene. Deficient MAT I and III activities and SAMe content in the liver have been associated with NAFLD, but whether MAT1A is required for normal VLDL assembly remains unknown. We investigated the role of MAT1A on VLDL assembly in two metabolic contexts: in 3-month-old MAT1A-knockout mice (3-KO), with no signs of liver injury, and in 8-month-old MAT1A-knockout mice (8-KO), harboring nonalcoholic steatohepatitis. In 3-KO mouse liver, there is a potent effect of MAT1A deletion on lipid handling, decreasing mobilization of TG stores, TG secretion in VLDL and phosphatidylcholine synthesis via phosphatidylethanolamine N-methyltransferase. MAT1A deletion also increased VLDL- apolipoprotein B secretion, leading to small, lipid-poor VLDL particles. Administration of SAMe to 3-KO mice for 7 days recovered crucial altered processes in VLDL assembly and features of the secreted lipoproteins. The unfolded protein response was activated in 8-KO mouse liver, in which TG accumulated and the phosphatidylcholine-to-phosphatidylethanolamine ratio was reduced in the endoplasmic reticulum, whereas secretion of TG and apolipoprotein B in VLDL was increased and the VLDL physical characteristics resembled that in 3-KO mice. MAT1A deletion also altered plasma lipid homeostasis, with an increase in lipid transport in low-density lipoprotein subclasses and decrease in high-density lipoprotein subclasses. Conclusion: MAT1A is required for normal VLDL assembly and plasma lipid homeostasis in mice. Impaired VLDL synthesis, mainly due to SAMe deficiency, contributes to NAFLD development in MAT1A-KO mice. (HEPATOLOGY 2011). Copyright © 2011 American Association for the Study of Liver Diseases.

Descripción

Se han estudiado los mecanismos moleculares responsables de la secreción de lípidos por el hígado en ratones knock-out que presentan diferentes estadios de la enfermedad de hígado graso no alcohólica (NAFLD). Estos animales carecen del gen Metionina adenosiltransferasa 1A (MAT1A), que se expresa en el hígado y cataliza la síntesis de S-adenosilmetionina (SAMe), principal donador biológico de metilos. El principal hallazgo descrito es que SAMe es imprescindible para el correcto ensamblaje y secreción de lipoproteínas de baja densidad (VLDL), complejos esenciales para el mantenimiento de la homeostasis lipídica del hígado y del organismo en conjunto. Así, la deficiencia de SAMe en los ratones MAT1A-KO favorece el desarrollo de NAFLD.

Foto grupo enero

REFERENCIA DEL GRUPO INVESTIGADOR
Ainara Cano realizó una tesis doctoral europea en la Facultad de Medicina de la Universidad del País Vasco (UPV/EHU), titulada “Papel del gen MAT1A en la homeostasis lipídica y orgánica de los lípidos” (2005-2009). El presente artículo es resultado de la colaboración de su grupo http://lipids-liver.net/, investigadores del CIC bioGUNE (Bizkaia) y la Universidad de Southern California (Keck School of Medicine, USA). Conocer los mecanismos fisiopatológicos que acompañan a la enfermedad de hígado graso no alcohólica (NAFLD) es su principal desafío.
Actualmente, Ainara es investigadora en la empresa biotecnológica One Way Liver (OWL). La compañía http://owlgenomics.com/ combina servicios e I+D, siendo su objetivo encontrar marcadores no invasivos de enfermedades, especialmente NAFLD, por medio del análisis UPLC-MS de metabolitos presentes en material biológico, como suero, tejido y células.

Más artículos en la revista SEBBM.

¿Acabas de publicar un artículo interesante?

Manda la referencia a través de nuestro formulario.  Límite de edad 32 años. Los artículos seleccionados serán destacados como artículos del mes y participarán en el Premio al mejor artículo de jóvenes de la SEBBM, que se entregará en el congreso de la SEBBM (inscripción y alojamiento gratuitos).

Otros "Artículos del mes"

A Mammalian Target of Rapamycin-Perilipin 3 (mTORC1-Plin3) Pathway is essential to Activate Lipophagy and Protects Against Hepatosteatosis

24-09-2021

Background and Aims: NAFLD is the most common hepatic pathology in western countries and no treatment is currently available. NAFLD is characterized by the aberrant hepatocellular accumulation of fatty acids...

Leer más

NF-κB/IKK activation by small extracellular vesicles within the SASP

07-09-2021

Cellular senescence plays an important role in different biological and pathological conditions. Senescent cells communicate with their microenvironment through a plethora of soluble factors, metalloproteases and extracellular vesicles (EV). Although...

Leer más

α-Helical peptidic scaffolds to target α-synuclein toxic species with nanomolar affinity

28-07-2021

α-Synuclein aggregation is a key driver of neurodegeneration in Parkinson's disease and related syndromes. Accordingly, obtaining a molecule that targets α-synuclein toxic assemblies with high affinity is a long-pursued objective...

Leer más

Neutrophil infiltration regulates clock-gene expression to organize daily hepatic metabolism

30-06-2021

Liver metabolism follows diurnal fluctuations through the modulation of molecular clock genes. Disruption of this molecular clock can result in metabolic disease but its potential regulation by immune cells remains...

Leer más

G6PD overexpression protects from oxidative stress and age-related hearing loss

23-05-2021

Aging of the auditory system is associated with the incremental production of reactive oxygen species (ROS) and the accumulation of oxidative damage in macromolecules, which contributes to cellular malfunction, compromises...

Leer más

Renal tubule Cpt1a overexpression protects from kidney fibrosis by restoring mitochondrial homeostasis

25-04-2021

Chronic kidney disease (CKD) remains a major epidemiological, clinical, and biomedical challenge. During CKD, renal tubular epithelial cells (TECs) present a persistent inflammatory and profibrotic response. Fatty acid oxidation (FAO)...

Leer más

Astrocyte-mediated switch in spike timing-dependent plasticity during hippocampal development

29-03-2021

Presynaptic spike timing-dependent long-term depression (t-LTD) at hippocampal CA3-CA1 synapses is evident until the 3rd postnatal week in mice, disappearing during the 4th week. At more mature stages, we found...

Leer más

Ceramide chain length–dependent protein sorting into selective endoplasmic reticulum exit sites

22-02-2021

Protein sorting in the secretory pathway is crucial to maintain cellular compartmentalization and homeostasis. In addition to coat-mediated sorting, the role of lipids in driving protein sorting during secretory transport...

Leer más

Antigen retrieval and clearing for whole-organ immunofluorescence by FLASH

25-01-2021

Advances in light-sheet and confocal microscopy now allow imaging of cleared large biological tissue samples and enable the 3D appreciation of cell and protein localization in their native organ environment...

Leer más

Viral Bcl2s' transmembrane domain interact with host Bcl2 proteins to control cellular apoptosis

08-01-2021

Viral control of programmed cell death relies in part on the expression of viral analogs of the B-cell lymphoma 2 (Bcl2) protein known as viral Bcl2s (vBcl2s). vBcl2s control apoptosis...

Leer más

Socios Protectores