RESUMO
Cancer cachexia is an involuntary loss of body weight, mostly of skeletal muscle. Previous research favors the existence of a microbiota-muscle crosstalk, so the aim of the study was to evaluate the impact of microbiota alterations induced by antibiotics on skeletal muscle proteins expression. Skeletal muscle proteome changes were investigated in control (CT) or C26 cachectic mice (C26) with or without antibiotic treatment (CT-ATB or C26-ATB, n = 8 per group). Muscle protein extracts were divided into a sarcoplasmic and myofibrillar fraction and then underwent label-free liquid chromatography separation, mass spectrometry analysis, Mascot protein identification, and METASCAPE platform data analysis. In C26 mice, the atrogen mafbx expression was 353% higher than CT mice and 42.3% higher than C26-ATB mice. No effect on the muscle protein synthesis was observed. Proteomic analyses revealed a strong effect of antibiotics on skeletal muscle proteome outside of cachexia, with adaptative processes involved in protein folding, growth, energy metabolism, and muscle contraction. In C26-ATB mice, proteome adaptations observed in CT-ATB mice were blunted. Differentially expressed proteins were involved in other processes like glucose metabolism, oxidative stress response, and proteolysis. This study confirms the existence of a microbiota-muscle axis, with a muscle response after antibiotics that varies depending on whether cachexia is present.
Assuntos
Antibacterianos , Caquexia , Músculo Esquelético , Proteoma , Caquexia/metabolismo , Caquexia/microbiologia , Animais , Músculo Esquelético/metabolismo , Músculo Esquelético/efeitos dos fármacos , Antibacterianos/farmacologia , Antibacterianos/efeitos adversos , Proteoma/metabolismo , Proteoma/análise , Camundongos , Neoplasias/metabolismo , Neoplasias/complicações , Neoplasias/tratamento farmacológico , Proteínas Musculares/metabolismo , Masculino , Proteômica/métodos , Microbiota/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacosRESUMO
PURPOSE OF REVIEW: This review provides the latest insight into the impact of consuming plant-based protein for older people. RECENT FINDINGS: According to the latest data, a healthy diet rich in plant-based-protein-rich-food could promote healthy aging. This health effect is partly because of the amino acid composition of proteins, as well as to the important constituents such as fiber and bioactive compounds found in the matrix. Furthermore, even though animal protein is more effective at stimulating muscle protein synthesis, a high consumption of plant protein (beyond 31âg/day) appears to enhance physical performance and reduce the risk of frailty in older individuals. SUMMARY: Recent literature highlights numerous health benefits for older people associated with a substantial intake of plant-based vs. animal-based protein, both in preventing and mitigating chronic age-related diseases and reducing the risk of all-cause mortality. However, a high intake of plant-based protein-rich products could pose risks of malnutrition and fiber-related intestinal intolerances. Further research is needed to assess the risk-benefit ratio of a high consumption of plant proteins in older individuals before we can make robust recommendations on how far animal proteins can be healthfully replaced with plant proteins.
Assuntos
Proteínas Animais da Dieta , Idoso , Humanos , Envelhecimento , Proteínas Animais da Dieta/administração & dosagem , Dieta Saudável/métodos , Fibras na Dieta , Proteínas Alimentares/administração & dosagem , Fragilidade/prevenção & controle , Envelhecimento Saudável , Proteínas de Vegetais Comestíveis/administração & dosagemRESUMO
TRUEFAD (TRUE Fiber Atrophy Distinction) is a bioimagery user-friendly tool developed to allow consistent and automatic measurement of myotube diameter in vitro, muscle fiber size and type using rodents and human muscle biopsies. This TRUEFAD package was set up to standardize and dynamize muscle research via easy-to-obtain images run on an open-source plugin for FIJI. We showed here both the robustness and the performance of our pipelines to correctly segment muscle cells and fibers. We evaluated our pipeline on real experiment image sets and showed consistent reliability across images and conditions. TRUEFAD development makes possible systematical and rapid screening of substances impacting muscle morphology for helping scientists focus on their hypothesis rather than image analysis.
Assuntos
Fibras Musculares Esqueléticas , Software , Humanos , Reprodutibilidade dos Testes , Fibras Musculares Esqueléticas/fisiologia , Processamento de Imagem Assistida por Computador/métodos , Técnicas de Cultura de CélulasRESUMO
Aging is associated with a decline in muscle mass and function, leading to increased risk for mobility limitations and frailty. Dietary interventions incorporating specific nutrients, such as pea proteins or inulin, have shown promise in attenuating age-related muscle loss. This study aimed to investigate the effect of pea proteins given with inulin on skeletal muscle in old rats. Old male rats (20 months old) were randomly assigned to one of two diet groups for 16 weeks: a 'PEA' group receiving a pea-protein-based diet, or a 'PEA + INU' group receiving the same pea protein-based diet supplemented with inulin. Both groups showed significant postprandial stimulation of muscle p70 S6 kinase phosphorylation rate after consumption of pea proteins. However, the PEA + INU rats showed significant preservation of muscle mass with time together with decreased MuRF1 transcript levels. In addition, inulin specifically increased PGC1-α expression and key mitochondrial enzyme activities in the plantaris muscle of the old rats. These findings suggest that dietary supplementation with pea proteins in combination with inulin has the potential to attenuate age-related muscle loss. Further research is warranted to explore the underlying mechanisms and determine the optimal dosage and duration of intervention for potential translation to human studies.
Assuntos
Proteínas de Ervilha , Humanos , Masculino , Animais , Ratos , Lactente , Inulina/farmacologia , Músculo Esquelético , Suplementos Nutricionais , EnvelhecimentoRESUMO
PURPOSE OF REVIEW: An increase in the plant-based characteristics of the diet is now recommended for human and planetary health. There is growing evidence that plant protein (PP) intake has beneficial effects on cardiometabolic risk. However, proteins are not consumed isolated and the protein package (lipid species, fiber, vitamins, phytochemicals, etc) may contribute, besides the protein effects per se, to explain the beneficial effects associated with PP-rich diets. RECENT FINDINGS: Recent studies have shown the potential of nutrimetabolomics to apprehend the complexity of both the human metabolism and the dietary habits, by providing signatures associated to the consumption of PP-rich diets. Those signatures comprised an important proportion of metabolites that were representative of the protein package, including specific amino acids (branched-chain amino acids and their derivates, glycine, lysine), but also lipid species (lysophosphatidylcholine, phosphatidylcholine, plasmalogens) and polyphenol metabolites (catechin sulfate, conjugated valerolactones and phenolic acids). SUMMARY: Further studies are needed to go deeper in the identification of all metabolites making part of the specific metabolomic signatures, associated to the large range of protein package constituents and their effects on the endogenous metabolism, rather than to the protein fraction itself. The objective is to determine the bioactive metabolites, as well as the modulated metabolic pathways and the mechanisms responsible for the observed effects on cardiometabolic health.
Assuntos
Aminoácidos , Doenças Cardiovasculares , Humanos , Proteínas de Plantas , Metabolômica , Doenças Cardiovasculares/prevenção & controle , LipídeosRESUMO
PURPOSE OF REVIEW: The current review provides an update on recent research regarding plant-based protein and their nutritional quality for older people. RECENT FINDINGS: There is growing evidence that plant-based proteins may be a valuable strategy for older people to prevent the health risks associated with consuming animal products and to promote better protein intake, as plant-based protein sources are rich in fibres and micronutrients. Although plant-based proteins are less anabolic than animal-derived proteins due to lower digestibility and deficiencies in some essential amino acids, several innovations in food processing and nutritional strategies have been developed to improve the quality of plant-based proteins. For example, the use of protein blends or green-processes as fermentation or germination could improve the nutritional qualities of plant-based foods that could be beneficial for older people, especially to prevent sarcopenia or metabolic disorders such as diabetes, obesity and cardiovascular diseases. SUMMARY: The use of plant-based protein sources could help older people diversify their protein sources and more easily meet recommended nutritional intake. Recent literature highlights several health benefits associated with increased consumption of vegetable foods. However, their efficiency on postprandial muscle protein synthesis remains to be evaluated and long-term studies are needed.
Assuntos
Proteínas de Vegetais Comestíveis , Sarcopenia , Animais , Humanos , Proteínas Alimentares , Sarcopenia/prevenção & controle , Valor Nutritivo , Aminoácidos EssenciaisRESUMO
Aging is associated with a progressive loss of skeletal muscle mass and function termed sarcopenia. Various metabolic alterations that occur with aging also increase the risk of undernutrition, which can worsen age-related sarcopenia. However, the impact of undernutrition on aged skeletal muscle remains largely under-researched. To build a deeper understanding of the cellular and molecular mechanisms underlying age-related sarcopenia, we characterized the undernutrition-induced changes in the skeletal muscle proteome in old rats. For this study, 20-month-old male rats were fed 50% or 100% of their spontaneous intake for 12 weeks, and proteomic analysis was performed on both slow- and fast-twitch muscles. Proteomic profiling of undernourished aged skeletal muscle revealed that undernutrition has profound effects on muscle proteome independently of its effect on muscle mass. Undernutrition-induced changes in muscle proteome appear to be muscle-type-specific: slow-twitch muscle showed a broad pattern of differential expression in proteins important for energy metabolism, whereas fast-twitch muscle mainly showed changes in protein turnover between undernourished and control rats. This first proteomic analysis of undernourished aged skeletal muscle provides new molecular-level insight to explain phenotypic changes in undernourished aged muscle. We anticipate this work as a starting point to define new biomarkers associated with undernutrition-induced muscle loss in the elderly.
Assuntos
Desnutrição , Sarcopenia , Envelhecimento/metabolismo , Animais , Masculino , Desnutrição/metabolismo , Músculo Esquelético/metabolismo , Proteoma/metabolismo , Proteômica , Ratos , Sarcopenia/metabolismoRESUMO
Middle-aged and master endurance athletes exhibit similar physical performance and long-term muscle adaptation to aerobic exercise. Nevertheless, we hypothesized that the short-term plasticity of the skeletal muscle might be distinctly altered for master athletes when they are challenged by a single bout of prolonged moderate-intensity exercise. Six middle-aged (37Y) and five older (50Y) master highly-trained athletes performed a 24-h treadmill run (24TR). Vastus lateralis muscle biopsies were collected before and after the run and assessed for proteomics, fiber morphometry, intramyocellular lipid droplets (LD), mitochondrial oxidative activity, extracellular matrix (ECM), and micro-vascularisation. Before 24TR, muscle fiber type morphometry, intramyocellular LD, oxidative activity, ECM and micro-vascularisation were similar between master and middle-aged runners. For 37Y runners, 24TR was associated with ECM thickening, increased capillary-to-fiber interface, and an 89% depletion of LD in type-I fibers. In contrast, for 50Y runners, 24TR did not alter ECM and capillarization and poorly depleted LDs. Moreover, an impaired succinate dehydrogenase activity and functional class scoring of proteomes suggested reduced oxidative phosphorylation post-24TR exclusively in 50Y muscle. Collectively, our data support that middle-aged and master endurance athletes exhibit distinct transient plasticity in response to a single bout of ultra-endurance exercise, which may constitute early signs of muscle aging for master athletes.
Assuntos
Atletas , Resistência Física , Envelhecimento/fisiologia , Exercício Físico/fisiologia , Humanos , Pessoa de Meia-Idade , Músculo Esquelético/fisiologia , Resistência Física/fisiologiaRESUMO
The aim of the study was to evaluate the association between physical activity, knee extensors (KE) performance (ie, isometric strength and fatigability), and biological parameters (ie, muscle structural, microvascular, and metabolic properties) in healthy very old men and women. Thirty very old adults (82 ± 1 years, 15 women) performed an isometric Quadriceps Intermittent Fatigue (QIF) test for the assessment of KE maximal force, total work (index of absolute performance), and fatigability. Muscle biopsies from the vastus lateralis muscle were collected to assess muscle fibers type and morphology, microvasculature, and enzymes activity. Correlation analyses were used to investigate the relationships between physical activity (steps/day, actimetry), KE performance, and biological data for each sex separately. Men, compared to women, showed greater total work at the QIF test (44 497 ± 8 629 Ns vs 26 946 ± 4 707 Ns; p < .001). Steps per day were correlated with total work only for women (r = 0.73, p = .011). In men, steps per day were correlated with the percentage (r = 0.57, p = .033), shape factor (r = 0.75, p = .002), and capillary tortuosity of type IIX fibers (r = 0.59, p = .035). No other relevant correlations were observed for men or women between steps per day and biological parameters. Physical activity level was positively associated with the capacity of very old women to perform a fatiguing test, but not maximal force production capacity of the KE. Physical activity of very old men was not correlated with muscle performance. We suggest that very old women could be at higher risk of autonomy loss and increasing the steps per day count could provide a sufficient stimulus for adaptations in less active women.
Assuntos
Fadiga Muscular , Músculo Quadríceps , Exercício Físico/fisiologia , Feminino , Humanos , Contração Isométrica/fisiologia , Joelho/fisiologia , Masculino , Fadiga Muscular/fisiologia , Músculo Esquelético/fisiologia , Músculo Quadríceps/fisiologiaRESUMO
Plant proteins are attracting rising interest due to their pro-health benefits and environmental sustainability. However, little is known about the nutritional value of pea proteins when consumed by older people. Herein, we evaluated the digestibility and nutritional efficiency of pea proteins compared to casein and whey proteins in old rats. Thirty 20-month-old male Wistar rats were assigned to an isoproteic and isocaloric diet containing either casein (CAS), soluble milk protein (WHEY) or Pisane™ pea protein isolate for 16 weeks. The three proteins had a similar effect on nitrogen balance, true digestibility and net protein utilization in old rats, which means that different protein sources did not alter body composition, tissue weight, skeletal muscle protein synthesis or degradation. Muscle mitochondrial activity, inflammation status and insulin resistance were similar between the three groups. In conclusion, old rats used pea protein with the same efficiency as casein or whey proteins, due to its high digestibility and amino acid composition. Using these plant-based proteins could help older people diversify their protein sources and more easily achieve nutritional intake recommendations.
Assuntos
Anabolizantes/farmacologia , Proteínas do Leite/farmacologia , Proteínas Musculares/metabolismo , Proteínas de Ervilha/farmacologia , Aminoácidos/metabolismo , Animais , Caseínas/farmacologia , Digestão/efeitos dos fármacos , Masculino , Músculo Esquelético/efeitos dos fármacos , Valor Nutritivo , Proteólise/efeitos dos fármacos , Ratos , Ratos Wistar , Proteínas do Soro do Leite/farmacologiaRESUMO
This study evaluates the capacity of a bread enriched with fermentable dietary fibres to modulate the metabolism and nutrients handling between tissues, gut and peripheral, in a context of overfeeding. Net fluxes of glucose, lactate, urea, short chain fatty acids (SCFA), and amino acids were recorded in control and overfed female mini-pigs supplemented or not with fibre-enriched bread. SCFA in fecal water and gene expressions, but not protein levels or metabolic fluxes, were measured in muscle, adipose tissue, and intestine. Fibre supplementation increased the potential for fatty acid oxidation and mitochondrial activity in muscle (acox, ucp2, sdha and cpt1-m, p < 0.05) as well as main regulatory transcription factors of metabolic activity such as pparα, pgc-1α and nrf2. All these features were associated with a reduced muscle fibre cross sectional area, resembling to controls (i.e., lean phenotype). SCFA may be direct inducers of these cross-talk alterations, as their feces content (+52%, p = 0.05) was increased in fibre-supplemented mini-pigs. The SCFA effects could be mediated at the gut level by an increased production of incretins (increased gcg mRNA, p < 0.05) and an up-regulation of SCFA receptors (increased gpr41 mRNA, p < 0.01). Hence, consumption of supplemented bread with fermentable fibres can be an appropriate strategy to activate muscle energy catabolism and limit the establishment of an obese phenotype.
Assuntos
Tecido Adiposo/metabolismo , Fibras na Dieta/administração & dosagem , Metabolismo Energético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Hipernutrição/metabolismo , Aminoácidos/metabolismo , Animais , Pão , Suplementos Nutricionais , Modelos Animais de Doenças , Ácidos Graxos Voláteis/metabolismo , Fezes/química , Feminino , Alimentos Fermentados , Glucose/metabolismo , Incretinas/metabolismo , Intestinos/metabolismo , Ácido Láctico/metabolismo , Suínos , Porco Miniatura , Ureia/metabolismoRESUMO
Chronic Mg2+ deficiency is the underlying cause of a broad range of health dysfunctions. As 25% of body Mg2+ is located in the skeletal muscle, Mg2+ transport and homeostasis systems (MgTHs) in the muscle are critical for whole-body Mg2+ homeostasis. In the present study, we assessed whether Mg2+ deficiency alters muscle fiber characteristics and major pathways regulating muscle physiology. C57BL/6J mice received either a control, mildly, or severely Mg2+-deficient diet (0.1%; 0.01%; and 0.003% Mg2+ wt/wt, respectively) for 14 days. Mg2+ deficiency slightly decreased body weight gain and muscle Mg2+ concentrations but was not associated with detectable variations in gastrocnemius muscle weight, fiber morphometry, and capillarization. Nonetheless, muscles exhibited decreased expression of several MgTHs (MagT1, CNNM2, CNNM4, and TRPM6). Moreover, TaqMan low-density array (TLDA) analyses further revealed that, before the emergence of major muscle dysfunctions, even a mild Mg2+ deficiency was sufficient to alter the expression of genes critical for muscle physiology, including energy metabolism, muscle regeneration, proteostasis, mitochondrial dynamics, and excitation-contraction coupling.
Assuntos
Proteínas de Transporte de Cátions/metabolismo , Homeostase/genética , Deficiência de Magnésio/genética , Magnésio/metabolismo , Músculo Esquelético/metabolismo , Animais , Modelos Animais de Doenças , Metabolismo Energético/genética , Camundongos , Camundongos Endogâmicos C57BL , Fibras Musculares Esqueléticas/metabolismo , Transdução de Sinais/genéticaRESUMO
(1) Background: Aging is associated with a progressive decline in muscle mass and function. Aging is also a primary risk factor for metabolic syndrome, which further alters muscle metabolism. However, the molecular mechanisms involved remain to be clarified. Herein we performed omic profiling to decipher in muscle which dominating processes are associated with healthy aging and metabolic syndrome in old men. (2) Methods: This study included 15 healthy young, 15 healthy old, and 9 old men with metabolic syndrome. Old men were selected from a well-characterized cohort, and each vastus lateralis biopsy was used to combine global transcriptomic and proteomic analyses. (3) Results: Over-representation analysis of differentially expressed genes (ORA) and functional class scoring of pathways (FCS) indicated that healthy aging was mainly associated with upregulations of apoptosis and immune function and downregulations of glycolysis and protein catabolism. ORA and FCS indicated that with metabolic syndrome the dominating biological processes were upregulation of proteolysis and downregulation of oxidative phosphorylation. Proteomic profiling matched 586 muscle proteins between individuals. The proteome of healthy aging revealed modifications consistent with a fast-to-slow transition and downregulation of glycolysis. These transitions were reduced with metabolic syndrome, which was more associated with alterations in NADH/NAD+ shuttle and ß-oxidation. Proteomic profiling further showed that all old muscles overexpressed protein chaperones to preserve proteostasis and myofiber integrity. There was also evidence of aging-related increases in reactive oxygen species but better detoxifications of cytotoxic aldehydes and membrane protection in healthy than in metabolic syndrome muscles. (4) Conclusions: Most candidate proteins and mRNAs identified herein constitute putative muscle biomarkers of healthy aging and metabolic syndrome in old men.
Assuntos
Síndrome Metabólica/metabolismo , Proteômica/métodos , Animais , Glicólise/genética , Glicólise/fisiologia , Humanos , Síndrome Metabólica/genética , Músculo Esquelético/metabolismo , Sarcopenia/genética , Sarcopenia/metabolismo , Transcriptoma/genéticaRESUMO
The mechanisms that are responsible for sarcopenia are numerous, but the altered muscle protein anabolic response to food intake that appears with advancing age plays an important role. Dietary protein quality needs to be optimized to counter this phenomenon. Blending different plant proteins is expected to compensate for the lower anabolic capacity of plant-based when compared to animal-based protein sources. The objective of this work was to evaluate the nutritional value of pasta products that were made from a mix of wheat semolina and faba bean, lentil, or split pea flour, and to assess their effect on protein metabolism as compared to dietary milk proteins in old rats. Forty-three old rats have consumed for six weeks isoproteic and isocaloric diets containing wheat pasta enriched with 62% to 79% legume protein (depending on the type) or milk proteins, i.e., casein or soluble milk proteins (SMP). The protein digestibility of casein and SMP was 5% to 14% higher than legume-enriched pasta. The net protein utilization and skeletal muscle protein synthesis rate were equivalent either in rats fed legume-enriched pasta diets or those fed casein diet, but lower than in rats fed SMP diet. After legume-enriched pasta intake, muscle mass, and protein accretion were in the same range as in the casein and SMP groups. Mixed wheat-legume pasta could be a nutritional strategy for enhancing the protein content and improving the protein quality, i.e., amino acid profile, of this staple food that is more adequate for maintaining muscle mass, especially for older individuals.
Assuntos
Ingestão de Alimentos/fisiologia , Fenômenos Fisiológicos da Nutrição do Idoso/fisiologia , Fabaceae , Proteínas do Leite/administração & dosagem , Proteínas Musculares/biossíntese , Músculo Esquelético/metabolismo , Valor Nutritivo , Proteínas de Vegetais Comestíveis/administração & dosagem , Proteínas/metabolismo , Triticum , Fatores Etários , Proteínas Animais da Dieta/administração & dosagem , Proteínas Animais da Dieta/metabolismo , Animais , Caseínas/administração & dosagem , Caseínas/metabolismo , Masculino , Proteínas do Leite/metabolismo , Proteínas de Vegetais Comestíveis/metabolismo , Proteólise , Ratos WistarRESUMO
Plant-sourced proteins offer environmental and health benefits, and research increasingly includes them in study formulas. However, plant-based proteins have less of an anabolic effect than animal proteins due to their lower digestibility, lower essential amino acid content (especially leucine), and deficiency in other essential amino acids, such as sulfur amino acids or lysine. Thus, plant amino acids are directed toward oxidation rather than used for muscle protein synthesis. In this review, we evaluate the ability of plant- versus animal-based proteins to help maintain skeletal muscle mass in healthy and especially older people and examine different nutritional strategies for improving the anabolic properties of plant-based proteins. Among these strategies, increasing protein intake has led to a positive acute postprandial muscle protein synthesis response and even positive long-term improvement in lean mass. Increasing the quality of protein intake by improving amino acid composition could also compensate for the lower anabolic potential of plant-based proteins. We evaluated and discussed four nutritional strategies for improving the amino acid composition of plant-based proteins: fortifying plant-based proteins with specific essential amino acids, selective breeding, blending several plant protein sources, and blending plant with animal-based protein sources. These nutritional approaches need to be profoundly examined in older individuals in order to optimize protein intake for this population who require a high-quality food protein intake to mitigate age-related muscle loss.
Assuntos
Anabolizantes , Proteínas Alimentares/administração & dosagem , Proteínas Musculares/administração & dosagem , Músculo Esquelético/fisiologia , Proteínas de Plantas/administração & dosagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Aminoácidos/análise , Animais , Proteínas Alimentares/farmacologia , Digestão , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas Musculares/análise , Proteínas Musculares/metabolismo , Fenômenos Fisiológicos da Nutrição , Proteínas de Plantas/análise , Proteínas de Plantas/metabolismo , Biossíntese de Proteínas/fisiologiaRESUMO
Magnesium (Mg2+) is critical for a number of biological processes and 25% body Mg2+ is located in the skeletal muscle. Mg2+ transport and homeostasis systems (MgTHs) regulate intracellular Mg2+ concentration and muscle MgTHs are thus related to whole body Mg2+ homeostasis. Nonetheless, few studies have investigated the regulation of muscle MgTHs under (patho)physiological conditions. Herein, we assessed the relationship between the expression of MgTHs genes (Trpm6, Trpm7, Magt1, Mrs2, Cnnm1-4, Slc41a1-3) and relevant pathways in human sarcopenia, which is one of the most dramatic physiologic changes affecting the human body. Transcriptomic data were compared between young adult (YO, 22 y, n = 11) and old (EL, 73 y, n = 13) men from the PROOF cohort. MgTH mRNA levels did not change with aging, with the exception of a slight decrease for Slc41a3. Nevertheless, interindividual variations of mRNA levels revealed strong correlations between MgTHs in the YO group, while few were maintained in the EL muscle. Moreover, in the YO muscle, different clusters of MgTH mRNAs strongly correlated with divers physiological (BMI, blood pressure) and muscle characteristics (intramyocellular droplets, capillarization); however, most correlations changed or disappeared in the EL muscle. Further investigations of the whole transcriptome identified several sets of mRNAs correlated with defined MgTHs. There again was a sharp difference between YO and EL muscles, as the number of mRNAs correlated with MgTHs strongly decreased with aging. Gene ontology analyses of these sets of correlated mRNAs revealed 6 biological processes common to YO and EL, 3 specific to the YO (RNA processing, translation, respiration), and 2 (regulation of catabolic process, Wnt signaling) to the EL muscle. Overall, these observations lead to questions about potential resilience to muscle Mg2+ homeostasis in the elderly.
Assuntos
Homeostase/genética , Magnésio/metabolismo , Músculo Esquelético/metabolismo , Transcriptoma , Adulto , Idoso , Estudos de Coortes , Humanos , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Adulto JovemRESUMO
BACKGROUND: Glucocorticoids (GC) play a major role in muscle atrophy. As skeletal muscle is a secretory organ, characterization of the muscle secretome elicited by muscle atrophy should allow to better understand the cellular mechanisms and to identify circulating biomarkers of this condition. Our project aimed to identify the changes in the muscle secretome associated with GC-induced muscle atrophy and susceptible to translate into circulation. METHODS: We have identified the GC-induced changes in the secretome of C2 C12 muscle cells by proteomic analysis, and then, we have determined how these changes translate into the circulation of mice or human subjects exposed to high concentrations of GC. RESULTS: This approach led us to identify Serpina3n as one of the most markedly secreted protein in response to GC. Our original in vitro results were confirmed in vivo by an increased expression of Serpina3n in skeletal muscle (3.9-fold; P < 0.01) and in the serum (two-fold; P < 0.01) of mice treated with GC. We also observed increased levels of the human orthologue Serpina3 in the serum of Cushing's syndrome patients compared with healthy controls matched for age and sex (n = 9/group, 2.5-fold; P < 0.01). An increase of Serpina3n was also demonstrated in muscle atrophy models mediated by GC such as cancer cachexia (four-fold; P < 0.01), sepsis (12.5-fold; P < 0.001), or diabetes (two-fold; P < 0.01). In contrast, levels of Serpina3n both in skeletal muscle and in the circulation were reduced in several models of muscle hypertrophy induced by myostatin inhibition (P < 0.01). Furthermore, a cluster of data suggests that the regulation of muscle Serpina3n involves mTOR, an essential determinant of the muscle cell size. CONCLUSIONS: Taken together, these data suggest that Serpina3n may represent a circulating biomarker of muscle atrophy associated to GC and, broadly, a reflection of dynamic changes in muscle mass.
Assuntos
Glucocorticoides/efeitos adversos , Atrofia Muscular/etiologia , Atrofia Muscular/metabolismo , Serpinas/metabolismo , Animais , Estudos de Casos e Controles , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Cromatografia Líquida , Síndrome de Cushing/complicações , Dexametasona/efeitos adversos , Modelos Animais de Doenças , Expressão Gênica , Humanos , Masculino , Camundongos , Atrofia Muscular/patologia , Mioblastos , Proteoma , Proteômica/métodos , Serpinas/sangue , Espectrometria de Massas em TandemRESUMO
Skeletal muscle, the most abundant body tissue, plays vital roles in locomotion and metabolism. Myostatin is a negative regulator of skeletal muscle mass. In addition to increasing muscle mass, Myostatin inhibition impacts muscle contractility and energy metabolism. To decipher the mechanisms of action of the Myostatin inhibitors, we used proteomic and transcriptomic approaches to investigate the changes induced in skeletal muscles of transgenic mice overexpressing Follistatin, a physiological Myostatin inhibitor. Our proteomic workflow included a fractionation step to identify weakly expressed proteins and a comparison of fast versus slow muscles. Functional annotation of altered proteins supports the phenotypic changes induced by Myostatin inhibition, including modifications in energy metabolism, fiber type, insulin and calcium signaling, as well as membrane repair and regeneration. Less than 10% of the differentially expressed proteins were found to be also regulated at the mRNA level but the Biological Process annotation, and the KEGG pathways analysis of transcriptomic results shows a great concordance with the proteomic data. Thus this study describes the most extensive omics analysis of muscle overexpressing Follistatin, providing molecular-level insights to explain the observed muscle phenotypic changes.
Assuntos
Hipertrofia/genética , Doenças Musculares/genética , Miostatina/genética , Proteômica , Transcriptoma/genética , Animais , Modelos Animais de Doenças , Folistatina/farmacologia , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica , Humanos , Hipertrofia/induzido quimicamente , Hipertrofia/patologia , Camundongos , Camundongos Transgênicos , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/patologia , Doenças Musculares/induzido quimicamente , Doenças Musculares/patologia , Miostatina/antagonistas & inibidores , Regeneração/genéticaRESUMO
Aging strongly affects the skeletal muscle and is associated with microvascular dysfunctions. Age is also a primary risk factor for the metabolic syndrome, which is a cluster of metabolic and cardiovascular symptoms. Among the metabolic syndrome components, hypertension is the most prevalent in elderly subjects and has a central role in vascular alterations. Despite critical clinical outcomes, the effects of hypertension and metabolic syndrome on skeletal muscle capillarization have poorly been investigated during aging. In the present study, muscle biopsies from normotensive young (YO) and elderly (ELc) men, and elderly men with hypertension (EL-HT) or metabolic syndrome (EL-MS) were assessed for the number of capillaries around a fiber (CAF), capillary-to-fiber perimeter exchange (CFPE), length of contact to perimeter of fiber ratio (LC/PF), capillary tortuosity, and for extracellular matrix (ECM) embedding capillaries. As capillarization and muscle mitochondrial oxidative capacity may be associated, we also investigated cytochrome c oxidase (COX) content. Our findings indicate that capillarization and COX did not change between normotensive adult and old individuals. They further reveal that hypertension in elderly men is associated with reduced CAF (ELc: 5.2 ± 0.4, EL-HT: 4.1 ± 0.2, P<0.02 for type I fibers; ELc: 4.1 ± 0.2, EL-HT: 3.1 ± 0.3, P<0.03 for type IIA fibers), CFPE (ELc: 7.9 ± 0.7, EL-HT: 6.4 ± 0.4 capillaries/1000 µm, P<0.03 for type I fibers; ELc: 6.5 ± 0.4, EL-HT: 5.2 ± 0.4 capillaries/1000 µm, P<0.03 for type IIA fibers), LC/PF (ELc: 23.3 ± 1.2, EL-HT: 17.8 ± 0.6%, P<0.01 for type I fibers; ELc: 19.8 ± 1.1, EL-HT: 15.6 ± 0.8%, P<0.01 for type IIA fibers) and capillary tortuosity, and with ECM endomysium fibrosis. Capillary rarefaction also correlated with lower COX content in the old hypertensive muscle. No further modification occurred with metabolic syndrome in elderly men. Collectively, our results suggest that hypertension plays a central role in muscle capillarization during aging, and that the other components of metabolic syndrome do not make major additional changes in the aged skeletal muscle capillary network.
Assuntos
Envelhecimento , Capilares/fisiopatologia , Hipertensão/fisiopatologia , Músculo Esquelético/irrigação sanguínea , Neovascularização Fisiológica , Fatores Etários , Idoso , Envelhecimento/patologia , Biópsia , Capilares/patologia , Complexo IV da Cadeia de Transporte de Elétrons/análise , Matriz Extracelular/patologia , Humanos , Hipertensão/diagnóstico , Hipertensão/patologia , Extremidade Inferior , Masculino , Fibras Musculares Esqueléticas/patologia , Fatores Sexuais , Adulto JovemRESUMO
Telomeres are nucleoprotein structures at the end of chromosomes which stabilize and protect them from nucleotidic degradation and end-to-end fusions. The G-rich telomeric single-stranded DNA overhang can adopt a four-stranded G-quadruplex DNA structure (G4). Stabilization of the G4 structure by binding of small molecule ligands enhances radiosensitivity of tumor cells, and this combined treatment represents a novel anticancer approach. We studied the effect of the platinum-derived G4-ligand, Pt-ctpy, in association with radiation on human glioblastoma (SF763 and SF767) and non-small cell lung cancer (A549 and H1299) cells in vitro and in vivo. Treatments with submicromolar concentrations of Pt-ctpy inhibited tumor proliferation in vitro with cell cycle alterations and induction of apoptosis. Non-toxic concentrations of the ligand were then combined with ionizing radiation. Pt-ctpy radiosensitized all cell lines with dose-enhancement factors between 1.32 and 1.77. The combined treatment led to increased DNA breaks. Furthermore, a significant radiosensitizing effect of Pt-ctpy in mice xenografted with glioblastoma SF763 cells was shown by delayed tumor growth and improved survival. Pt-ctpy can act in synergy with radiation for efficient killing of cancer cells at concentrations at which it has no obvious toxicity per se, opening perspectives for future therapeutic applications.