Small extracellular vesicle targeting of hypothalamic AMPKα1 promotes weight loss in leptin receptor deficient mice

Background and aims: Leptin receptor (LEPR) deficiency promotes severe obesity and metabolic disorders. However, the current therapeutic options against this syndrome are scarce. Methods: db/db mice and their wildtypes were systemically treated with neuronal-targeted small extracellular vesicles (sEVs) harboring a plasmid encoding a dominant negative mutant of AMP-activated protein kinase alpha 1 (AMPKα1-DN) driven by steroidogenic factor 1 (SF1) promoter; this approach allowed to modulate AMPK activity, specifically in SF1 cells of the ventromedial nucleus of the hypothalamus (VMH). Animals were metabolically phenotyped. Results: db/db mice intravenously injected with SF1-AMPKα1-DN loaded sEVs showed a marked feeding-independent weight loss and decreased adiposity, associated with increased sympathetic tone, brown adipose tissue (BAT) thermogenesis and browning of white adipose tissue (WAT).Conclusion: Overall, this evidence indicates that specific modulation of hypothalamic AMPK using a sEV-based technology may be a suitable strategy against genetic forms of obesity, such as LEPR deficiencyMinisterio de Ciencia y Universidades co-funded by the FEDER Program of EU (CD: BFU2017-87721; RN: RTI2018-099413-B-I00 and RED2018-102379-T; ML: RTI2018-101840-B-I00, PID2021-128145NB-I00 and PDC2022-133958-I00). “la Caixa” Foundation (ID100010434), under the agreement LCF/PR/HR19/52160022 (ML); EuroNanoMed III (RA & ML: EURONANOMED2019-050-ENAMEP); European Research Council (RN: ERC Synergy Grant-2019-WATCH-810331)S

Faeces‐derived extracellular vesicles participate in the onset of barrier dysfunction leading to liver diseases

International audienceThe role of extracellular vesicles (EVs) from faeces (fEVs) and small circulating EVs (cEVs) in liver diseases such as non-alcoholic fatty diseases (NAFLD) and nonalcoholic steatohepatitis (NASH) has not been demonstrated. fEVs and cEVs of healthy donors, NAFLD and NASH patients were isolated and characterized. The effects of EVs were evaluated in intestinal, endothelial, Kupffer and stellate cells. Nonmuscular myosin light chain kinase (nmMLCK) deficient mice were used in vivo. Bacterial origins of fEVs were analysed by 16s rDNA gene sequencing. fEVs and small cEVs were composed of prokaryotic and eukaryotic origins. Only NASH-fEVs exerted deleterious effects. NASH-fEVs increased intestinal permeability and reduced expression of tight junction proteins that were prevented by nmMLCK inhibition, increased endothelial cell permeability and inflammatory cytokines and chemokines requiring TLR4/lipopolysaccharide pathway. NASH-fEVs and NASH-cEVs activated profibrotic and proinflammatory proteins of hepatic stellate cells. Treatment with NASH-fEVs evoked an increase in intestinal permeability in wild type but not in nmMLCK deficient mice. Bacterial origins of fEVs were different between NAFLD and NASH patients and 16 amplicon sequence variants were differentially abundant. We demonstrate that fEVs actively participate in barrier dysfunctions leading to liver injuries underscoring the role of nmMLCK and lipopolysaccharide carried by fEVs