ABSTRACT
Non-alcoholic steatohepatitis (NASH) is one of the fastest growing liver diseases worldwide, and oxidative stress is one of NASH main key drivers. Nicotinamide adenine dinucleotide phosphate (NADPH) is the ultimate donor of reductive power to a number of antioxidant defences. Here, we explored the potential of increasing NADPH levels to prevent NASH progression. We used nicotinamide riboside (NR) supplementation or a G6PD-tg mouse line harbouring an additional copy of the human G6PD gene. In a NASH mouse model induced by feeding mice a methionine-choline deficient (MCD) diet for three weeks, both tools increased the hepatic levels of NADPH and ameliorated the NASH phenotype induced by the MCD intervention, but only in female mice. Boosting NADPH levels in females increased the liver expression of the antioxidant genes Gsta3, Sod1 and Txnrd1 in NR-treated mice, or of Gsr for G6PD-tg mice. Both strategies significantly reduced hepatic lipid peroxidation. NR-treated female mice showed a reduction of steatosis accompanied by a drop of the hepatic triglyceride levels, that was not observed in G6PD-tg mice. NR-treated mice tended to reduce their lobular inflammation, showed a reduction of the NK cell population and diminished transcription of the damage marker Lcn2. G6PD-tg female mice exhibited a reduction of their lobular inflammation and hepatocyte ballooning induced by the MCD diet, that was related to a reduction of the monocyte-derived macrophage population and the Tnfa, Ccl2 and Lcn2 gene expression. As conclusion, boosting hepatic NADPH levels attenuated the oxidative lipid damage and the exhausted antioxidant gene expression specifically in female mice in two different models of NASH, preventing the progression of the inflammatory process and hepatic injury.
Subject(s)
Non-alcoholic Fatty Liver Disease , Female , Mice , Humans , Animals , Non-alcoholic Fatty Liver Disease/drug therapy , Non-alcoholic Fatty Liver Disease/genetics , Non-alcoholic Fatty Liver Disease/metabolism , NADP/metabolism , Antioxidants/metabolism , Liver/metabolism , Inflammation/metabolism , Choline/metabolism , Methionine/metabolism , Mice, Inbred C57BL , Disease Models, AnimalABSTRACT
Reversible and sub-lethal stresses to the mitochondria elicit a program of compensatory responses that ultimately improve mitochondrial function, a conserved anti-aging mechanism termed mitohormesis. Here, we show that harmol, a member of the beta-carbolines family with anti-depressant properties, improves mitochondrial function and metabolic parameters, and extends healthspan. Treatment with harmol induces a transient mitochondrial depolarization, a strong mitophagy response, and the AMPK compensatory pathway both in cultured C2C12 myotubes and in male mouse liver, brown adipose tissue and muscle, even though harmol crosses poorly the blood-brain barrier. Mechanistically, simultaneous modulation of the targets of harmol monoamine-oxidase B and GABA-A receptor reproduces harmol-induced mitochondrial improvements. Diet-induced pre-diabetic male mice improve their glucose tolerance, liver steatosis and insulin sensitivity after treatment with harmol. Harmol or a combination of monoamine oxidase B and GABA-A receptor modulators extend the lifespan of hermaphrodite Caenorhabditis elegans or female Drosophila melanogaster. Finally, two-year-old male and female mice treated with harmol exhibit delayed frailty onset with improved glycemia, exercise performance and strength. Our results reveal that peripheral targeting of monoamine oxidase B and GABA-A receptor, common antidepressant targets, extends healthspan through mitohormesis.
Subject(s)
Aging , Antidepressive Agents , Harmine , Mitochondria , Mitophagy , Monoamine Oxidase , Receptors, GABA-A , Harmine/analogs & derivatives , Harmine/pharmacology , Antidepressive Agents/pharmacology , Mitochondria/drug effects , Mitophagy/drug effects , Muscle Fibers, Skeletal/drug effects , AMP-Activated Protein Kinase Kinases/metabolism , Muscle, Skeletal/drug effects , Liver/drug effects , Aging/drug effects , Insulin Resistance , Glucose Intolerance/metabolism , Prediabetic State/metabolism , Monoamine Oxidase/metabolism , Receptors, GABA-A/metabolism , Longevity/drug effects , Caenorhabditis elegans , Drosophila melanogaster , Frailty/prevention & control , Physical Conditioning, Animal , Models, Animal , Male , Female , Animals , Mice , Fatty Liver/metabolism , Adipose Tissue, Brown/drug effectsABSTRACT
Obesity is associated to a low grade of chronic inflammation leading to metabolic stress, insulin resistance, metabolic syndrome, dislipidemia, cardiovascular disease, and even cancer. A Mediterranean diet has been shown to reduce systemic inflammatory factors, insulin resistance, and metabolic syndrome. In this scenario, precision nutrition may provide complementary approaches to target the metabolic alterations associated to "unhealthy obesity". In a previous work, we described a pomegranate extract (PomE) rich in punicalagines to augment markers of browning and thermogenesis in human differentiated adipocytes and to augment the oxidative respiratory capacity in human differentiated myocytes. Herein, we have conducted a preclinical study of high-fat-diet (HFD)-induced obesity where PomE augments the systemic energy expenditure (EE) contributing to a reduction in the low grade of chronic inflammation and insulin resistance associated to obesity. At the molecular level, PomE promotes browning and thermogenesis in adipose tissue, reducing inflammatory markers and augmenting the reductive potential to control the oxidative stress associated to the HFD. PomE merits further investigation as a complementary approach to alleviate obesity, reducing the low grade of chronic inflammation and metabolic stress.
