Methionine adenosyltransferase 1a antisense oligonucleotides activate the liver-brown adipose tissue axis preventing obesity and associated hepatosteatosis

Altered methionine metabolism is associated with weight gain in obesity. The methionine adenosyltransferase (MAT), catalyzing the first reaction of the methionine cycle, plays an important role regulating lipid metabolism. However, its role in obesity, when a plethora of metabolic diseases occurs, is still unknown. By using antisense oligonucleotides (ASO) and genetic depletion of Mat1a, here, we demonstrate that Mat1a deficiency in diet-induce obese or genetically obese mice prevented and reversed obesity and obesity-associated insulin resistance and hepatosteatosis by increasing energy expenditure in a hepatocyte FGF21 dependent fashion. The increased NRF2-mediated FGF21 secretion induced by targeting Mat1a, mobilized plasma lipids towards the BAT to be catabolized, induced thermogenesis and reduced body weight, inhibiting hepatic de novo lipogenesis. The beneficial effects of Mat1a ASO were abolished following FGF21 depletion in hepatocytes. Thus, targeting Mat1a activates the liver-BAT axis by increasing NRF2-mediated FGF21 secretion, which prevents obesity, insulin resistance and hepatosteatosis. High methionine and S-adenosylmethionine serum levels are related with obesity. Here the authors show that knockdown of methionine adenosyltransferase by using antisense oligonucleotides provides beneficial effects in obesity and comorbidities.This work was supported by Ayudas para apoyar grupos de investigacion del sistema Universitario Vasco (IT971-16) and MCIU/AEI/FEDER, UE (RTI2018-095134-B-100) (to P.A.), (RTI2018-099413-B-I00 and RED2018-102379-T) (to R.N.), PID2020119486RB-100 (to M.V.R.) and (RTI2018-096759-A-100) (to T.C.D). EFSD/Lilly European Diabetes Research Program, MICIU (PID2019-104399RB-I00), Fundacion AECC PROYE19047SABI, and Comunidad de Madrid IMMUNOTHERCAN-CM B2017/BMD-3733 (to G.S.). La CAIXA Foundation LCF/PR/HP17/52190004, MINECO-FEDER SAF2017-87301-R, AYUDAS FUNDACION BBVA A EQUIPOS DE INVESTIGACION CIENTIFICA UMBRELLA 2018 and AECC Scientific Foundation, grant name: Rare Cancers 2017 (to M.L.M.-C.). AECC Scientific Foundation (to T.C.D.). Xunta de Galicia 2020-PG015 (to R.N.) Gilead Sciences International Research Scholars Program in Liver Disease (to M.V.R.). Personal fellows: E.P.F. was awarded with Juan de la Cierva-Formacion, FJC2018-035449-I. C.F. was awarded with Sara Borrell (CD19/00078). CIC bioGUNE thanks MCIU for the Severo Ochoa Excellence Accreditation (SEV-2016-0644). The authors thank Dr. Manuel Lafitas laboratory (Getxo, Bizkaia, Spain) for his valuable help in the analysis of biochemical parameters