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Aging biology entails a cell/tissue deregulated metabolism that affects all levels of biological organization. Therefore, the application of “omic” techniques that are closer to phenotype, such as metabolomics, to the study of the aging process should be a turning point in the definition of cellular processes involved. The main objective of the present study was to describe the changes in plasma metabolome associated with biological aging and the role of sex in the metabolic regulation during aging. A high-throughput untargeted metabolomic analysis was applied in plasma samples to detect hub metabolites and biomarkers of aging incorporating a sex/gender perspective. A cohort of 1030 healthy human adults (45.9% females, and 54.1% males) from 50 to 98 years of age was used. Results were validated using two independent cohorts (1: n = 146, 53% females, 30–100 years old; 2: n = 68, 70% females, 19–107 years old). Metabolites related to lipid and aromatic amino acid (AAA) metabolisms arose as the main metabolic pathways affected by age, with a high influence of sex. Globally, we describe changes in bioenergetic pathways that point to a decrease in mitochondrial β-oxidation and an accumulation of unsaturated fatty acids and acylcarnitines that could be responsible for the increment of oxidative damage and inflammation characteristic of this physiological process. Furthermore, we describe for the first time the importance of gut-derived AAA catabolites in the aging process describing novel biomarkers that could contribute to better understand this physiological process but also age-related diseases. This research was funded by the Spanish Ministry of Science,Innovation, and Universities (grant RTI2018-099200-B- I00, and PID2022-143140OB-I00, co-funded by the European Regional Development Fund. “A way to build Europe”), and the Generalitat of Catalonia (Agency for Management of University and Research Grants [2021SGR00990] and Department of Health [SLT002/16/00250])to R.P. The work is also supported by “la Caixa” Foundation (Grant Agreement LCF/PR/HR21/52410002) to M.J. IRBLleida is a CERCAProgramme/Generalitat of Catalonia. This work was also partiallysupported by Instituto de Salud Carlos III (Madrid, Spain) through the research grants PI15/01934, PI18/01022, PI20/01090, and PI21/01361 (co-funded by the European Regional Development Fund. “A way to make Europe”), and the Catalan Government (AGAUR,#SGR2017-0734, ICREA Academia Award 2021) to J.M.F-R.

Decreased content and activity of the mechanistic target of rapamycin (mTOR) signalling pathway, as well as the mTOR complex 1 (mTORC1) itself, are key traits for animal species and human longevity. Since mTORC1 acts as a master regulator of intracellular metabolism, it is respon sible, at least in part, for the longevous phenotype. Conversely, increased content and activity of mTOR signalling and mTORC1 are hallmarks of ageing. Additionally, constitutive and aberrant activity of mTORC1 is also found in age-related diseases such as Alzheimer’s disease (AD) and cancer. The downstream processes regulated through this network are diverse, and depend upon nutrient availability. Hence, multiple nutritional strategies capable of regulating mTORC1 activity and, consequently, delaying the ageing process and the development of age-related diseases, are under continuous study. Among these, the restriction of calories is still the most studied and ro bust intervention capable of downregulating mTOR signalling and feasible for application in the human population. Research by the authors was supported by the Spanish Ministry of Science, Innovation, and Universities (Ministerio de Ciencia, Innovación y Universidades, co-financed by FEDER funds from the European Union ‘A way to build Europe’, grant RTI2018-099200-B-I00), the IRBLleida-Diputació de Lleida (PIRS2021), and the Generalitat of Catalonia: Agency for Management of University and Research Grants (2017SGR696) to R.P. IRBLleida is a CERCA Programme/Generalitat of Catalonia

Fatty acids are key components in the structural diversity of lipids and play a strategic role in the functional properties of lipids which determine the integrity of neuronal and glial cell membranes, the generation of lipid signaling mediators, and the chemical reactivity of acyl chains. The present study analyzes using gas chromatography the fatty acid profiles of 13 regions of the human central nervous system in healthy individuals ranging from 40 to 80 years old. The outcomes suggest the existence of general traits in fatty acid composition such as an average chain length of 18 carbon atoms, high monounsaturated fatty acid content, and predominance in polyunsaturated fatty acids of those of series n-6 over series n-3 which are shared by all brain regions regardless of age. Our results also show a general sustained and relatively well-preserved lipid profile throughout the adult lifespan in most studied regions (olive, upper vermis, substantia nigra, thalamus, hippocampus, putamen, caudate, occipital cortex, parietal cortex, entorhinal cortex, and frontal cortex) with minor changes that are region-dependent. In contrast, of particular relevance is the involvement of the inferior temporal cortex and cingulate cortex. It is proposed that during normal human brain aging, the lipid profile is resistant to changes with age in most human brain regions to ensure cell survival and function, but some particular regions involved in specific memory domains are greatly affected. Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This research was funded by the Spanish Ministry of Science, Innovation, and Universities (grant RTI2018-099200-B-I00), the IRBLleida-Dipuatació de Lleida (PIRS2021), and the Generalitat of Catalonia: Agency for Management of University and Research Grants (2017SGR696) to R.P. This study was cofnanced by FEDER funds from the European Union (“A way to build Europe”). IRBLleida is a CERCA Programme/Generalitat of Catalonia.

A species-specific lipidome profile is an inherent feature linked to longevity in the animal kingdom. However, there is a lack of lipidomic studies on human longevity. Here, we use mass spectrometry-based lipidomics to detect and quantify 151 sphingolipid molecular species and use these to define a phenotype of healthy humans with exceptional life span. Our results demonstrate that this profile specifically comprises a higher content of complex glycosphingolipids (hexosylceramides and gangliosides), and lower levels of ceramide species from the de novo pathway, sphingomyelin and sulfatide; while for ceramide-derived signaling compounds, their content remains unchanged. Our findings suggest that structural glycosphingolipids may be more relevant to achieve the centenarian condition than signaling sphingolipids. We acknowledge funding from the Spanish Ministry of Science, Innovation and Universities (RTI2018-099200-B-I00) and the Generalitat of Catalonia, Agency for management of University and Research Grants (2017SGR696) and Department of Health (SLT002/16/00250) to R.P., and Spanish Ministry of Education and Science (SAF2013-44663-R) and the ‘Red Tematica de Investigación Cooperativa en Envejecimiento y Fragilidad’ (RETICEF) (ISCIII2012-RED-43-029) to J.V. This study has been co-financed by FEDER funds from the European Union (“A way to build Europe”). I.P. was supported by a University of Lleida Predoctoral Fellowship. K.H. was supported by a Dementia Australia Research Foundation Scholarship.

Human prefrontal cortex (hPFC) is a recent evolutionarily developed brain region involved in cognitive functions. Human cognitive functions decline during aging. Yet the molecular mechanisms underlying the functional deterioration of the neural cells of this brain region still remain to be fully described.In this review, we explore the role of lipids in hPFC aging. Firstly, we briefly consider the approaches used to identify lipid species in brain tissue with special attention paid to a lipidomics analysis. Then, as the evolution process has conferred a specific lipid profile on the hPFC, we consider the lipidome of hPFC. In addition, the role of lipids in hPFC aging, and in particular, the cognitive decline associated with aging, is discussed. Finally, nutritional and pharmacological interventions designed to modulate this process are examined. It is suggested that the dysfunction of key cellular processes secondarily to the damage of lipid membrane underlies the cognitive decline of hPFC during aging.Lipidomics methods are and will continue to be key tools in the effort to gain additional insights into the aging of the human brain.

Current shreds of evidence point to the entorhinal cortex (EC) as the origin of the Alzheimer’s disease (AD) pathology in the cerebrum. Compared with other cortical areas, the neurons from this brain region possess an inherent selective vulnerability derived from particular oxidative stress conditions that favor increased mitochondrial molecular damage with early bioenergetic involvement. This alteration of energy metabolism is the starting point for subsequent changes in a multitude of cell mechanisms, leading to neuronal dysfunction and, ultimately, cell death. These events are induced by changes that come with age, creating the substrate for the alteration of several neuronal pathways that will evolve toward neurodegeneration and, consequently, the development of AD pathology. In this context, the present review will focus on description of the biological mechanisms that confer vulnerability specifically to neurons of the entorhinal cortex, the changes induced by the aging process in this brain region, and the alterations at the mitochondrial level as the earliest mechanism for the development of AD pathology. Current findings allow us to propose the existence of an altered allostatic mechanism at the entorhinal cortex whose core is made up of mitochondrial oxidative stress, lipid metabolism, and energy production, and which, in a positive loop, evolves to neurodegeneration, laying the basis for the onset and progression of AD pathology. Research by the authors was supported by the Institute of Health Carlos III (FIS grantsPI14/00757, PI14/00328, PI20/0155), the Spanish Ministry of Science, Innovation, and Universities(Ministerio de Ciencia, Innovación y Universidades, grant RTI2018-099200-B-I00), and the Generalitatof Catalonia: Agency for Management of University and Research Grants (2017SGR696) to M.P-O.,I.F., and R.P. This study was co-financed by FEDER funds from the European Union (‘A way tobuild Europe’).

Celiac disease (CD) is an autoimmune enteropathy linked to alterations of metabolism. Currently, limited untargeted metabolomic studies evaluating differences in the plasma metabolome of CD subjects have been documented. We engage in a metabolomic study that analyzes plasma metabolome in 17 children with CD treated with a gluten-free diet and 17 healthy control siblings in order to recognize potential changes in metabolic networks. Our data demonstrates the persistence of metabolic defects in CD subjects in spite of the dietary treatment, affecting a minor but significant fraction (around 4%, 209 out of 4893 molecular features) of the analyzed plasma metabolome. The affected molecular species are mainly, but not exclusively, lipid species with a particular affectation of steroids and derivatives (indicating an adrenal gland affectation), glycerophospholipids (to highlight phosphatidic acid), glycerolipids (with a special affectation of diacylglycerols), and fatty acyls (eicosanoids). Our findings are suggestive of an activation of the diacylglycerol-phosphatidic acid signaling pathway in CD that may potentially have detrimental effects via activation of several targets including protein kinases such as mTOR, which could be the basis of the morbidity and mortality connected with untreated CD. However, more studies are necessary to validate this idea regarding CD., Regional Government of Andalusia, Excellence Research (Project No P12-AGR-2581), Spanish Ministry of Science, Innovation, and Universities (Ministerio de Ciencia, Innovación y Universidades, RTI2018-099200-BI00), Generalitat of Catalonia: Agency for Management of University and Research Grants (2017SGR696), Department of Health (SLT002/16/00250), FEDER - European Union (“A way to build Europe”)., IRBLleida - CERCA Programme/Generalitat of Catalonia, “Investigation grant program by the Association of Celiacs and Sensitive to Gluten of the Community of Madrid

Like other human body cell systems the human brain is a target of the physiological aging process. Specific regions of the human brain exhibit differential vulnerabilities to aging. Yet the basic molecular mechanisms that underlie the preservation or deterioration of neurons and cerebral functions are little known. In this chapter, we focus attention on the role of lipids and lipid oxidation and the importance of the cross-regional differences in human brain aging. In particular, we first offer a brief approach to the lipidome of human brain, the relationship between lipids and lipoxidation-derived molecular damage, the changes in lipid profiles with aging, and the specific targets of lipoxidative damage in human brain during aging. We propose that lipid composition and damage be seen as the molecular substrate which gives rise to the restricted set of modified proteins, and that the functional categories involved may be considered putative collaborative factors contributing to human brain aging.

Complex I, a component of the electron transport chain, plays a central functional role in cell bioenergetics and the biology of free radicals. The structural and functional N module of complex I is one of the main sites of the generation of free radicals. The NDUFV2 subunit/N1a cluster is a component of this module. Furthermore, the rate of free radical production is linked to animal longevity. In this review, we explore the hypothesis that NDUFV2 is the only conserved core subunit designed with a regulatory function to ensure correct electron transfer and free radical production, that low gene expression and protein abundance of the NDUFV2 subunit is an evolutionary adaptation needed to achieve a longevity phenotype, and that these features are determinants of the lower free radical generation at the mitochondrial level and a slower rate of aging of long-lived animals.

The nonenzymatic adduction of malondialdehyde (MDA) to the protein amino groups leads to the formation of malondialdehyde-lysine (MDALys). The degree of unsaturation of biological membranes and the intracellular oxidative conditions are the main factors that modulate MDALys formation. The low concentration of this modification in the different cellular components, found in a wide diversity of tissues and animal species, is indicative of the presence of a complex network of cellular protection mechanisms that avoid its cytotoxic effects. In this review, we will focus on the chemistry of this lipoxidation-derived protein modification, the specificity of MDALys formation in proteins, the methodology used for its detection and quantification, the MDA-lipoxidized proteome, the metabolism of MDA-modified proteins, and the detrimental effects of this protein modification. We also propose that MDALys is an indicator of the rate of aging based on findings which demonstrate that (i) MDALys accumulates in tissues with age, (ii) the lower the concentration of MDALys the greater the longevity of the animal species, and (iii) its concentration is attenuated by anti-aging nutritional and pharmacological interventions Research by the authors was supported by the Spanish Ministry of Economy and Competitiveness, Institute of Health Carlos III (FIS grants PI13/00584 and PI14/00328), the Spanish Ministry of Science, Innovation, and Universities (Ministerio de Ciencia, Innovación y Universidades, RTI2018-099200-BI00), and the Generalitat of Catalonia: Agency for Management of University and Research Grants (2017SGR696), and Department of Health (SLT002/16/00250) to RP. This study has been co-financed by FEDER funds from the European Union (“A way to build Europe”). IRBLleida is a CERCA Programme/Generalitat of Catalonia.

Available evidences point to methionine metabolism as a key target to study the molecular adaptive mechanisms underlying differences in longevity. The plasma methionine metabolic profile was determined using a LC-MS/MS platform to systematically define specific phenotypic patterns associated with genotypes of human extreme longevity (centenarians). Our findings demonstrate the presence of a specific plasma profile associated with human longevity characterized by an enhanced transsulfuration pathway and tricarboxylic acid (TCA) cycle intermediates, as well as a reduced content of specific amino acids. Furthermore, our work reveals that centenarians maintain a strongly correlated methionine metabolism, suggesting an improved network integrity, homeostasis and more tightly regulated metabolism. We have discovered a particular methionine signature related to the condition of extreme longevity, allowing the identification of potential mechanisms and biomarkers of healthy aging.

Lipids are closely associated with brain structure and function. However, the potential changes in the lipidome induced by aging remain to be elucidated. In this study, we used chromatographic techniques and a mass spectrometry-based approach to evaluate age-associated changes in the lipidome of the frontal cortex and cerebellum obtained from adult male Wistar rats (8 months), aged male Wistar rats (26 months), and aged male Wistar rats submitted to a methionine restriction diet (MetR) as an anti-aging intervention for 8 weeks. The outcomes revealed that only small changes (about 10%) were observed in the lipidome profile in the cerebellum and frontal cortex during aging, and these changes differed, in some cases, between regions. Furthermore, a MetR diet partially reversed the effects of the aging process. Remarkably, the most affected lipid classes were ether-triacylglycerols, diacylglycerols, phosphatidylethanolamine N-methylated, plasmalogens, ceramides, and cholesterol esters. When the fatty acid profile was analyzed, we observed that the frontal cortex is highly preserved during aging and maintained under MetR, whereas in the cerebellum minor changes (increased monounsaturated and decreased polyunsaturated contents) were observed and not reversed by MetR. We conclude that the rat cerebellum and frontal cortex have efficient mechanisms to preserve the lipid profile of their cell membranes throughout their adult lifespan in order to maintain brain structure and function. A part of the small changes that take place during aging can be reversed with a MetR diet applied in old age. This research was funded by the Spanish Ministry of Science, Innovation, and Universities (grant RTI2018-099200-B-I00), and the Generalitat of Catalonia: Agency for Management of University and Research Grants (2017SGR696) to R.P.; and from Spanish Ministry of Economy and Competitiveness, Institute of Health Carlos III (PI20-0155) to M.P.-O. This study was co-financed by FEDER funds from the European Union (“A way to build Europe”). IRBLleida is a CERCA Programme/Generalitat of Catalonia.

Maximum longevity (ML) varies significantly across animal species, but the underlying molecular mechanisms remain poorly understood. Recent studies and omics approaches suggest that phenotypic traits of ML could to converge in the mammalian target of rapamycin (mTOR) signalling pathway. The present study is a comparative approach using heart tissue from 8 mammalian species with a ML ranging from 3.5 to 46 years. Gene expression, protein content, and concentration of regulatory metabolites of the mTOR complex 1 (mTORC1) were measured using droplet digital PCR, western blot and mass spectrometry, respectively. Our results demonstrate 1) the existence of differences species-specific in gene expression and protein content of mTORC1; 2) that the achievement of a longevity phenotype requires decreased and inhibited mTORC1; 3) decreased content of mTORC1 activators in long-lived animals, and 4) independence of phylogeny relationships on these changes. Altogether, our findings support mTORC1 down-regulation to achieve a longevous phenotype. This work was supported by the Spanish Ministry of Economy and Competitiveness, Institute of Health Carlos III (grant number PI14/00328), the Spanish Ministry of Science, Innovation and Universities (RTI2018-099200-B-I00), and the Generalitat of Catalonia, Agency for Management of University and Research Grants (2017SGR696) and Department of Health (SLT002/16/00250) to R.P. This study has been co-financed by FEDER funds from the European Union (“A way to build Europe”).

Methionine restriction (MetR) in animal models extends maximum longevity and seems to promote renoprotection by attenuating kidney injury. MetR has also been proven to affect several metabolic pathways including lipid metabolism. However, there is a lack of studies about the effect of MetR at old age on the kidney metabolome. In view of this, a mass spectrometry-based high-throughput metabolomic and lipidomic profiling was undertaken of renal cortex samples of three groups of male rats&mdash, An 8-month-old Adult group, a 26-month-old Aged group, and a MetR group that also comprised of 26-month-old rats but were subjected to an 80% MetR diet for 7 weeks. Additionally, markers of mitochondrial stress and protein oxidative damage were analyzed by mass spectrometry. Our results showed minor changes during aging in the renal cortex metabolome, with less than 59 differential metabolites between the Adult and Aged groups, which represents about 4% of changes in the kidney metabolome. Among the compounds identified are glycerolipids and lipid species derived from arachidonic acid metabolism. MetR at old age preferentially induces lipid changes affecting glycerophospholipids, docosanoids, and eicosanoids. No significant differences were observed between the experimental groups in the markers of mitochondrial stress and tissue protein damage. More than rejuvenation, MetR seems to induce a metabolic reprogramming.

Fatty acids are key components in the structural diversity of lipids and play a strategic role in the functional properties of lipids which determine the structural and functional integrity of neural cell membranes, the generation of lipid signaling mediators, and the chemical reactivity of acyl chains. The present study analyzes the profile of lipid fatty acid composition of membranes of human frontal cortex area 8 in individuals ranging from 40 to 90 years old. Different components involved in polyunsaturated fatty acid biosynthesis pathways, as well as adaptive defense mechanisms involved in the lipid-mediated modulation of inflammation, are also assessed. Our results show that the lipid profile in human frontal cortex is basically preserved through the adult life span to decay at advanced ages, which is accompanied by an adaptive proactive anti-inflammatory response possibly geared to ensuring cell survival and function.

A molecular description of the mechanisms by which aging is produced is still very limited. Here, we have determined the plasma metabolite profile by using high-throughput metabolome profiling technologies of 150 healthy humans ranging from 30 to 100 years of age. Using a nontargeted approach, we detected 2,678 metabolite species in plasma, and the multivariate analyses separated perfectly two groups indicating a specific signature for each gender. In addition, there is a set of gender-shared metabolites, which change significantly during aging with a similar tendency. Among the identified molecules, we found vitamin D2-related compound, phosphoserine (40:5), monoacylglyceride (22:1), diacylglyceride (33:2), and resolvin D6, all of them decreasing with the aging process. Finally, we found three molecules that directly correlate with age and seven that inversely correlate with age, independently of gender. Among the identified molecules (6 of 10 according to exact mass and retention time), we found a proteolytic product (l-γ-glutamyl-l-leucine), which increased with age. On the contrary, a hydroxyl fatty acid (25-hydroxy-hexacosanoic), a polyunsaturated fatty acid (eicosapentaenoic acid), two phospholipids (phosphocholine [42:9]and phosphoserine [42:3]) and a prostaglandin (15-keto-prostaglandin F2α) decreased with aging. These results suggest that lipid species and their metabolism are closely linked to the aging process.

Human brain aging is the physiological process which underlies as cause of cognitive decline in the elderly and the main risk factor for neurodegenerative diseases such as Alzheimer's disease. Human neurons are functional throughout a healthy adult lifespan, yet the mechanisms that maintain function and protect against neurodegenerative processes during aging are unknown. Here we show that protein oxidative and glycoxidative damage significantly increases during human brain aging, with a breakpoint at 60 years old. This trajectory is coincident with a decrease in the content of the mitochondrial respiratory chain complex I–IV. We suggest that the deterioration in oxidative stress homeostasis during aging induces an adaptive response of stress resistance mechanisms based on the sustained expression of REST, and increased or decreased expression of Akt and mTOR, respectively, over the adult lifespan in order to preserve cell neural survival and function. R.C. received predoctoral fellowships from the Autonomous Government of Catalonia. We thank T. Yohannan for editorial help. Research reported in this publication was supported by the Spanish Ministry of Economy and Competitiveness, Institute of Health Carlos III (FIS Grants PI14/00757 and PI14/00328), and the Autonomous Government of Catalonia (2014SGR69 and 2014SGR168) to I.F. and R.P. This study was co-financed by FEDER funds from the European Union (‘a way to build Europe’).

Lipids played a determinant role in the evolution of the brain. It is postulated that the morphological and functional diversity among neural cells of the human central nervous system (CNS) is projected and achieved through the expression of particular lipid profiles. The present study was designed to evaluate the differential vulnerability to oxidative stress mediated by lipids through a cross-regional comparative approach. To this end, we compared 12 different regions of CNS of healthy adult subjects, and the fatty acid profile and vulnerability to lipid peroxidation, were determined by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS), respectively. In addition, different components involved in PUFA biosynthesis, as well as adaptive defense mechanisms against lipid peroxidation, were also measured by western blot and immunohistochemistry, respectively. We found that: i) four fatty acids (18.1n-9, 22:6n-3, 20:1n-9, and 18:0) are significant discriminators among CNS regions; ii) these differential fatty acid profiles generate a differential selective neural vulnerability (expressed by the peroxidizability index); iii) the cross-regional differences for the fatty acid profiles follow a caudal-cranial gradient which is directly related to changes in the biosynthesis pathways which can be ascribed to neuronal cells; and iv) the higher the peroxidizability index for a given human brain region, the lower concentration of the protein damage markers, likely supported by the presence of adaptive antioxidant mechanisms. In conclusion, our results suggest that there is a region-specific vulnerability to lipid peroxidation and offer evidence of neuronal mechanisms for polyunsaturated fatty acid biosynthesis in the human central nervous system.

Rapamycin consistently increases longevity in mice although the mechanism of action of this drug is unknown. In the present investigation we studied the effect of rapamycin on mitochondrial oxidative stress at the same dose that is known to increase longevity in mice (14 mg of rapamycin/kg of diet). Middle aged mice (16 months old) showed significant age-related increases in mitochondrial ROS production at complex I, accumulation of mtDNA fragments inside nuclear DNA, mitochondrial protein lipoxidation, and lipofuscin accumulation compared to young animals (4 months old) in the liver. After 7 weeks of dietary treatment all those increases were totally or partially (lipofuscin) abolished by rapamycin, middle aged rapamycin-treated animals showing similar levels in those parameters to young animals. The decrease in mitochondrial ROS production was due to qualitative instead of quantitative changes in complex I. The decrease in mitochondrial protein lipoxidation was not due to decreases in the amount of highly oxidizable unsaturated fatty acids. Rapamycin also decreased the amount of RAPTOR (of mTOR complex) and increased the amounts of the PGC1-α and ATG13 proteins. The results are consistent with the possibility that rapamycin increases longevity in mice at least in part by lowering mitochondrial ROS production and increasing autophagy, decreasing the derived final forms of damage accumulated with age which are responsible for increased longevity. The decrease in lipofuscin accumulation induced by rapamycin adds to previous information suggesting that the increase in longevity induced by this drug can be due to a decrease in the rate of aging. © 2016 Elsevier Inc. Sin financiación 3.340 JCR (2016) Q1, 12/49 Geriatrics and Gerontology UEM

It has been described that dietary cysteine reverses many of the beneficial changes induced by methionine restriction in aging rodents. In this investigation male Wistar rats were subjected to diets low in methionine, supplemented with cysteine, or simultaneously low in methionine and supplemented with cysteine. The results obtained in liver showed that cysteine supplementation reverses the decrease in mitochondrial ROS generation induced by methionine restriction at complex I. Methionine restriction also decreased various markers of oxidative and non-oxidative stress on mitochondrial proteins which were not reversed by cysteine. Instead, cysteine supplementation also lowered protein damage in association with decreases in mTOR activation. The results of the present study add the decrease in mitochondrial ROS production to the various beneficial changes induced by methionine restriction that are reversed by cysteine dietary supplementation.

Celiac disease (CD) is an autoimmune enteropathy associated with alterations of metabolism. Metabolomics studies, although limited, showed changes in choline, choline-derived lipids, and methionine concentrations, which could be ascribed to alterations in one-carbon metabolism. To date, no targeted metabolomics analysis investigating di erences in the plasma choline/methionine metabolome of CD subjects are reported. This work is a targeted metabolomic study that analyzes 37 metabolites of the one-carbon metabolism in 17 children with CD, treated with a gluten-free diet and 17 healthy control siblings, in order to establish the potential defects in this metabolic network. Our results demonstrate the persistence of defects in the transsulfuration pathway of CD subjects, despite dietary treatment, while choline metabolism, methionine cycle, and folate cycle seem to be reversed and preserved to healthy levels. These findings describe for the first time, a metabolic defect in one-carbon metabolism which could have profound implications in the physiopathology and treatment of CD., Junta de Andalucía P12-AGR-2581, Spanish Ministry of Science, Innovation, and Universities (Ministerio de Ciencia, Innovacion y Universidades) RTI2018-099200-BI00, Generalitat of Catalonia: Agency for Management of University and Research Grants 2017SGR696, Department of Health SLT002/16/00250, European Union (EU), Grant "Investigation grant program by the SPAO" 2020 edition

Mitochondrial reactive oxygen species (ROS) production, specifically at complex I (Cx I), has been widely suggested to be one of the determinants of species longevity. The present study follows a comparative approach to analyse complex I in heart tissue from 8 mammalian species with a longevity ranging from 3.5 to 46 years. Gene expression and protein content of selected Cx I subunits were analysed using droplet digital PCR (ddPCR) and western blot, respectively. Our results demonstrate: 1) the existence of species-specific differences in gene expression and protein content of Cx I in relation to longevity; 2) the achievement of a longevity phenotype is associated with low protein abundance of subunits NDUFV2 and NDUFS4 from the matrix hydrophilic domain of Cx I; and 3) long-lived mammals show also lower levels of VDAC (voltage-dependent anion channel) amount. These differences could be associated with the lower mitochondrial ROS production and slower aging rate of long-lived animals and, unexpectedly, with a low content of the mitochondrial permeability transition pore in these species., Graphical abstract Image 1, Highlights • There are species-specific differences in gene expression and protein content of Cx I. • The achievement of a longevity phenotype is associated with low protein abundance of subunits NDUFV2 and NDUFS4 from the matrix hydrophilic domain of Cx I. • Long-lived mammals show also lower levels of VDAC (voltage-dependent anion channel) amount. • These differences can be causally associated with the aging rate of long-lived animals.

Lipids were determinants in the appearance and evolution of life. Recent studies disclose the existence of a link between lipids and animal longevity. Findings from both comparative studies and genetics and nutritional interventions in invertebrates, vertebrates, and exceptionally long-lived animal species—humans included—demonstrate that both the cell membrane fatty acid profile and lipidome are a species-specific optimized evolutionary adaptation and traits associated with longevity. All these emerging observations point to lipids as a key target to study the molecular mechanisms underlying differences in longevity and suggest the existence of a lipidome profile of long life. Research by the authors was supported by the Spanish Ministry of Science, Innovation, and Universities (Ministerio de Ciencia, Innovación y Universidades, RTI2018-099200-BI00), and the Generalitat of Catalonia: Agency for Management of University and Research Grants (2017SGR696) and Department of Health (SLT002/16/00250) to RP. This study was co-financed by FEDER funds from the European Union (“A way to build Europe”). IRBLleida is a CERCA Programme/Generalitat of Catalonia.