RESUMO
Dysregulated NLRP3 inflammasome activity results in uncontrolled inflammation, which underlies many chronic diseases. Although mitochondrial damage is needed for the assembly and activation of the NLRP3 inflammasome, it is unclear how macrophages are able to respond to structurally diverse inflammasome-activating stimuli. Here we show that the synthesis of mitochondrial DNA (mtDNA), induced after the engagement of Toll-like receptors, is crucial for NLRP3 signalling. Toll-like receptors signal via the MyD88 and TRIF adaptors to trigger IRF1-dependent transcription of CMPK2, a rate-limiting enzyme that supplies deoxyribonucleotides for mtDNA synthesis. CMPK2-dependent mtDNA synthesis is necessary for the production of oxidized mtDNA fragments after exposure to NLRP3 activators. Cytosolic oxidized mtDNA associates with the NLRP3 inflammasome complex and is required for its activation. The dependence on CMPK2 catalytic activity provides opportunities for more effective control of NLRP3 inflammasome-associated diseases.
Assuntos
DNA Mitocondrial/biossíntese , Inflamassomos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Animais , Biocatálise , Citosol/metabolismo , Fator Regulador 1 de Interferon/metabolismo , Lipopolissacarídeos/farmacologia , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Camundongos , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Núcleosídeo-Fosfato Quinase/genética , Núcleosídeo-Fosfato Quinase/metabolismo , Oxirredução , Transdução de Sinais , Receptores Toll-Like/imunologiaRESUMO
Estrogen receptor α (ERα) action plays an important role in pancreatic ß-cell function and survival; thus, it is considered a potential therapeutic target for the treatment of type 2 diabetes in women. However, the mechanisms underlying the protective effects of ERα remain unclear. Because ERα regulates mitochondrial metabolism in other cell types, we hypothesized that ERα may act to preserve insulin secretion and promote ß-cell survival by regulating mitochondrial-endoplasmic reticulum (EndoRetic) function. We tested this hypothesis using pancreatic islet-specific ERα knockout (PERαKO) mice and Min6 ß-cells in culture with Esr1 knockdown (KD). We found that Esr1-KD promoted reactive oxygen species production that associated with reduced fission/fusion dynamics and impaired mitophagy. Electron microscopy showed mitochondrial enlargement and a pro-fusion phenotype. Mitochondrial cristae and endoplasmic reticulum were dilated in Esr1-KD compared with ERα replete Min6 ß-cells. Increased expression of Oma1 and Chop was paralleled by increased oxygen consumption and apoptosis susceptibility in ERα-KD cells. In contrast, ERα overexpression and ligand activation reduced both Chop and Oma1 expression, likely by ERα binding to consensus estrogen-response element sites in the Oma1 and Chop promoters. Together, our findings suggest that ERα promotes ß-cell survival and insulin secretion through maintenance of mitochondrial fission/fusion-mitophagy dynamics and EndoRetic function, in part by Oma1 and Chop repression.
Assuntos
Apoptose , Estresse do Retículo Endoplasmático , Receptor alfa de Estrogênio/metabolismo , Células Secretoras de Insulina/metabolismo , Mitocôndrias/metabolismo , Mitofagia , Animais , Sobrevivência Celular , Receptor alfa de Estrogênio/genética , Feminino , Insulina/genética , Insulina/metabolismo , Metaloproteases/biossíntese , Metaloproteases/genética , Camundongos , Camundongos Knockout , Mitocôndrias/genética , Proteínas Mitocondriais/biossíntese , Proteínas Mitocondriais/genética , Espécies Reativas de Oxigênio/metabolismo , Fator de Transcrição CHOP/biossíntese , Fator de Transcrição CHOP/genéticaRESUMO
Mitochondrial dynamics refers to the constant remodeling of mitochondrial populations by multiple cellular pathways that help maintain mitochondrial health and function. Disruptions in mitochondrial dynamics often lead to mitochondrial dysfunction, which is frequently associated with disease in rodents and humans. Consistent with this, obesity is associated with reduced mitochondrial function in white adipose tissue, partly via alterations in mitochondrial dynamics. Several proteins, including the E3 ubiquitin ligase membrane-associated RING-CH-type finger 5 (MARCH5), are known to regulate mitochondrial dynamics; however, the role of these proteins in adipocytes has been poorly studied. Here, we show that MARCH5 is regulated by peroxisome proliferator-activated receptor-γ (PPARγ) during adipogenesis and is correlated with fat mass across a panel of genetically diverse mouse strains, in ob/ob mice, and in humans. Furthermore, manipulation of MARCH5 expression in vitro and in vivo alters mitochondrial function, affects cellular metabolism, and leads to differential regulation of several metabolic genes. Thus our data demonstrate an association between mitochondrial dynamics and metabolism that defines MARCH5 as a critical link between these interconnected pathways.
Assuntos
Adipócitos/metabolismo , Tecido Adiposo/metabolismo , Proteínas de Membrana/metabolismo , Síndrome Metabólica/metabolismo , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , Obesidade/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Células 3T3-L1 , Adipogenia , Adulto , Animais , Técnicas de Silenciamento de Genes , Humanos , Masculino , Camundongos , Camundongos Knockout , Pessoa de Meia-Idade , Proteínas Mitocondriais/genética , PPAR gama/genética , PPAR gama/metabolismo , Ubiquitina-Proteína Ligases/genéticaRESUMO
Elevated hepatic ceramide levels have been implicated in both insulin resistance (IR) and hepatic steatosis. To understand the factors contributing to hepatic ceramide levels in mice of both sexes, we have quantitated ceramides in a reference population of mice, the Hybrid Mouse Diversity Panel that has been previously characterized for a variety of metabolic syndrome traits. We observed significant positive correlations between Cer(d18:1/16:0) and IR/hepatic steatosis, consistent with previous findings, although the relationship broke down between sexes, as females were less insulin resistant, but had higher Cer(d18:1/16:0) levels than males. The sex difference was due in part to testosterone-mediated repression of ceramide synthase 6. One ceramide species, Cer(d18:1/20:0), was present at higher levels in males and was associated with IR only in males. Clear evidence of gene-by-sex and gene-by-diet interactions was observed, including sex-specific genome-wide association study results. Thus, our studies show clear differences in how hepatic ceramides are regulated between the sexes, which again suggests that the physiological roles of certain hepatic ceramides differ between the sexes.
Assuntos
Ceramidas/metabolismo , Dieta , Resistência à Insulina/genética , Resistência à Insulina/fisiologia , Fígado/metabolismo , Caracteres Sexuais , Animais , Ceramidas/biossíntese , Feminino , Fígado/efeitos dos fármacos , Masculino , Camundongos , Testosterona/farmacologiaRESUMO
Limb girdle muscular dystrophy 2A is due to loss-of-function mutations in the Calpain 3 (CAPN3) gene. Our previous data suggest that CAPN3 helps to maintain the integrity of the triad complex in skeletal muscle. In Capn3 knock-out mice (C3KO), Ca2+ release and Ca2+/calmodulin kinase II (CaMKII) signaling are attenuated. We hypothesized that calpainopathy may result from a failure to transmit loading-induced Ca2+-mediated signals, necessary to up-regulate expression of muscle adaptation genes. To test this hypothesis, we compared transcriptomes of muscles from wild type (WT) and C3KO mice subjected to endurance exercise. In WT mice, exercise induces a gene signature that includes myofibrillar, mitochondrial and oxidative lipid metabolism genes, necessary for muscle adaptation. C3KO muscles fail to activate the same gene signature. Furthermore, in agreement with the aberrant transcriptional profile, we observe a commensurate functional defect in lipid metabolism whereby C3KO muscles fail to release fatty acids from stored triacylglycerol. In conjunction with the defects in oxidative metabolism, C3KO mice demonstrate reduced exercise endurance. Failure to up-regulate genes in C3KO muscles is due, in part, to decreased levels of PGC1α, a transcriptional co-regulator that orchestrates the muscle adaptation response. Destabilization of PGC1α is attributable to decreased p38 MAPK activation via diminished CaMKII signaling. Thus, we elucidate a pathway downstream of Ca2+-mediated CaMKII activation that is dysfunctional in C3KO mice, leading to reduced transcription of genes involved in muscle adaptation. These studies identify a novel mechanism of muscular dystrophy: a blunted transcriptional response to muscle loading resulting in chronic failure to adapt and remodel.
Assuntos
Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Calpaína/genética , Proteínas Musculares/genética , Distrofia Muscular do Cíngulo dos Membros/genética , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Animais , Sinalização do Cálcio , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/biossíntese , Calpaína/biossíntese , Regulação da Expressão Gênica , Humanos , Camundongos , Camundongos Knockout , Proteínas Musculares/biossíntese , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Distrofia Muscular do Cíngulo dos Membros/metabolismo , Distrofia Muscular do Cíngulo dos Membros/fisiopatologia , Mutação , Estresse Oxidativo/genética , Ativação Transcricional/genética , Proteínas Quinases p38 Ativadas por Mitógeno/genéticaRESUMO
Women in the modern era are challenged with facing menopausal symptoms as well as heightened disease risk associated with increasing adiposity and metabolic dysfunction for up to three decades of life. Treatment strategies to combat metabolic dysfunction and associated pathologies have been hampered by our lack of understanding regarding the biological causes of these clinical conditions and our incomplete understanding regarding the effects of estrogens and the tissue-specific functions and molecular actions of its receptors. In this chapter we provide evidence supporting a critical and protective role for skeletal muscle estrogen receptor α in the maintenance of metabolic homeostasis and insulin sensitivity. Studies identifying the critical ER-regulated pathways essential for disease prevention will lay the important foundation for the rational design of novel therapeutic strategies to improve the health of women while limiting secondary complications that have plagued traditional hormone replacement interventions.
Assuntos
Metabolismo Energético , Estrogênios/metabolismo , Resistência à Insulina , Músculo Esquelético/metabolismo , Receptores de Estrogênio/metabolismo , Animais , Metabolismo Energético/efeitos dos fármacos , Terapia de Reposição de Estrogênios , Feminino , Homeostase , Humanos , Masculino , Menopausa/metabolismo , Doenças Metabólicas/metabolismo , Doenças Metabólicas/fisiopatologia , Doenças Metabólicas/prevenção & controle , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/fisiopatologia , Receptores de Estrogênio/efeitos dos fármacos , Transdução de SinaisRESUMO
Obesity is associated with increased breast cancer (BrCA) incidence. Considering that inactivation of estrogen receptor (ER)α promotes obesity and metabolic dysfunction in women and female mice, understanding the mechanisms and tissue-specific sites of ERα action to combat metabolic-related disease, including BrCA, is of clinical importance. To study the role of ERα in adipose tissue we generated fat-specific ERα knock-out (FERKO) mice. Herein we show that ERα deletion increased adipocyte size, fat pad weight, and tissue expression and circulating levels of the secreted glycoprotein, lipocalin 2 (Lcn2), an adipokine previously associated with BrCA development. Chromatin immunoprecipitation and luciferase reporter studies showed that ERα binds the Lcn2 promoter to repress its expression. Because adipocytes constitute an important cell type of the breast microenvironment, we examined the impact of adipocyte ERα deletion on cancer cell behavior. Conditioned medium from ERα-null adipocytes and medium containing pure Lcn2 increased proliferation and migration of a subset of BrCA cells in culture. The proliferative and promigratory effects of ERα-deficient adipocyte-conditioned medium on BrCA cells was reversed by Lcn2 deletion. BrCA cell responsiveness to exogenous Lcn2 was heightened in cell types where endogenous Lcn2 expression was minimal, but components of the Lcn2 signaling pathway were enriched, i.e. SLC22A17 and 3-hydroxybutyrate dehydrogenase (BDH2). In breast tumor biopsies from women diagnosed with BrCA we found that BDH2 expression was positively associated with adiposity and circulating Lcn2 levels. Collectively these data suggest that reduction of ERα expression in adipose tissue promotes adiposity and is linked with the progression and severity of BrCA via increased adipocyte-specific Lcn2 production and enhanced tumor cell Lcn2 sensitivity.
Assuntos
Proteínas de Fase Aguda/metabolismo , Tecido Adiposo/metabolismo , Receptor alfa de Estrogênio/metabolismo , Lipocalinas/metabolismo , Obesidade/metabolismo , Proteínas Oncogênicas/metabolismo , Células 3T3-L1 , Proteínas de Fase Aguda/genética , Adipócitos/citologia , Adipócitos/metabolismo , Tecido Adiposo/citologia , Animais , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Progressão da Doença , Receptor alfa de Estrogênio/genética , Feminino , Perfilação da Expressão Gênica , Células HEK293 , Humanos , Immunoblotting , Lipocalina-2 , Lipocalinas/sangue , Lipocalinas/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Obesos , Obesidade/genética , Proteínas Oncogênicas/sangue , Proteínas Oncogênicas/genética , Regiões Promotoras Genéticas/genética , Ligação Proteica , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
AIMS/HYPOTHESIS: The aim of this work was to investigate the prospective relationship between low birthweight (LBW) and type 2 diabetes risk later in life and the mediation effects of type 2 diabetes biomarkers linking LBW to type 2 diabetes risk. METHODS: We measured baseline plasma concentrations of various type 2 diabetes biomarkers in 1,259 incident type 2 diabetes cases and 1,790 controls in the Women's Health Initiative-Observational Study. Self-report birthweights of the participants were recorded. The total effect of LBW on type 2 diabetes risk was partitioned into effects that were mediated by a specific biomarker and effects that were not mediated by this biomarker, using counterfactual model-based mediation analysis. RESULTS: LBW was significantly associated with increased risk of type 2 diabetes. Compared with women with birthweight 3.63-4.54 kg, women with LBW (<2.72 kg) had a multivariable-adjusted OR of 2.15 (95% CI, 1.54, 3.00). Insulin resistance (indicated by HOMA-IR) mediated 47% of the total effect. Decreased sex hormone-binding globulin (SHBG) concentration accounted for 24%, elevated E-selectin concentration accounted for 25% and increased systolic blood pressure accounted for 8% of the total effect of LBW on type 2 diabetes risk. (Due to interactions among different mediators, the sum of each individual mediator's contribution could exceed 100%, without an upper limit.) CONCLUSIONS/INTERPRETATION: LBW is directly predictive of higher risk of type 2 diabetes later in life. The effect of LBW on type 2 diabetes risk seems mainly mediated by insulin resistance, which is further explained by circulating levels of SHBG and E-selectin and systolic blood pressure. The study provides potential risk stratification in a population at greater risk of developing type 2 diabetes.
Assuntos
Biomarcadores/sangue , Peso ao Nascer , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/etnologia , Idoso , Pressão Sanguínea , Estudos de Casos e Controles , Selectina E/sangue , Etnicidade , Feminino , Humanos , Incidência , Pessoa de Meia-Idade , Análise Multivariada , Razão de Chances , Pós-Menopausa , Estudos Prospectivos , Fatores de Risco , Inquéritos e Questionários , Resultado do TratamentoRESUMO
ERα is expressed in macrophages and other immune cells known to exert dramatic effects on glucose homeostasis. We investigated the impact of ERα expression on macrophage function to determine whether hematopoietic or myeloid-specific ERα deletion manifests obesity-induced insulin resistance in mice. Indeed, altered plasma adipokine and cytokine levels, glucose intolerance, insulin resistance, and increased adipose tissue mass were observed in animals harboring a hematopoietic or myeloid-specific deletion of ERα. A similar obese phenotype and increased atherosclerotic lesion area was displayed in LDL receptor-KO mice transplanted with ERα(-/-) bone marrow. In isolated macrophages, ERα was necessary for repression of inflammation, maintenance of oxidative metabolism, IL-4-mediated induction of alternative activation, full phagocytic capacity in response to LPS, and oxidized LDL-induced expression of ApoE and Abca1. Furthermore, we identified ERα as a direct regulator of macrophage transglutaminase 2 expression, a multifunctional atheroprotective enzyme. Our findings suggest that diminished ERα expression in hematopoietic/myeloid cells promotes aspects of the metabolic syndrome and accelerates atherosclerosis in female mice.
Assuntos
Aterosclerose/patologia , Medula Óssea/metabolismo , Receptor alfa de Estrogênio/fisiologia , Homeostase , Adiposidade , Animais , Receptor alfa de Estrogênio/genética , Receptor alfa de Estrogênio/metabolismo , Feminino , Glucose/metabolismo , Resistência à Insulina , Interleucina-4/fisiologia , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos KnockoutRESUMO
Parasympathetic dysfunction after chronic myocardial infarction (MI) is known to predispose ventricular tachyarrhythmias (ventricular tachycardia/ventricular fibrillation [VT/VF]). VT/VF after MI is more common in males than females. The mechanisms underlying the decreased vagal tone and the associated sex difference in the occurrence of VT/VF after MI remain elusive. In this study, using optogenetic approaches, we found that responses of glutamatergic vagal afferent neurons were impaired following chronic MI in male mice, leading to reduced reflex efferent parasympathetic function. Molecular analyses of vagal ganglia demonstrated reduced glutamate levels, accompanied by decreased mitochondrial function and impaired redox status in infarcted males versus sham animals. Interestingly, infarcted females demonstrated reduced vagal sensory impairment, associated with greater vagal ganglia glutamate levels and decreased vagal mitochondrial dysfunction and oxidative stress compared with infarcted males. Treatment with 17ß-estradiol mitigated this pathological remodeling and improved vagal neurotransmission in infarcted male mice. These data suggest that a decrease in efferent vagal tone following MI results from reduced glutamatergic afferent vagal signaling that may be due to impaired redox homeostasis in the vagal ganglia, which subsequently leads to pathological remodeling in a sex-dependent manner. Importantly, estrogen prevents pathological remodeling and improves parasympathetic function following MI.
Assuntos
Estradiol , Ácido Glutâmico , Infarto do Miocárdio , Transmissão Sináptica , Nervo Vago , Animais , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/fisiopatologia , Masculino , Feminino , Camundongos , Estradiol/farmacologia , Estradiol/metabolismo , Nervo Vago/efeitos dos fármacos , Nervo Vago/metabolismo , Nervo Vago/fisiopatologia , Transmissão Sináptica/efeitos dos fármacos , Ácido Glutâmico/metabolismo , Fatores Sexuais , Modelos Animais de Doenças , Estresse Oxidativo/efeitos dos fármacos , Camundongos Endogâmicos C57BLRESUMO
Glucagon is a peptide hormone that acts via receptor-mediated signaling predominantly in the liver to raise glucose levels by hepatic glycogen breakdown or conversion of noncarbohydrate, 3 carbon precursors to glucose by gluconeogenesis. Glucagon is administered to reverse severe hypoglycemia, a clinical complication associated with type 1 diabetes. However, due to low stability and solubility at neutral pH, there are limitations in the current formulations of glucagon. Trehalose methacrylate-based nanoparticles were utilized as the stabilizing and solubilizing moiety in the system reported herein. Glucagon was site-selectively modified to contain a cysteine at amino acid number 24 to covalently attach to the methacrylate-based polymer containing pyridyl disulfide side chains. PEG2000 dithiol was employed as the crosslinker to form uniform nanoparticles. Glucagon nanogels were monitored in Dulbecco's phosphate-buffered saline (DPBS) pH 7.4 at various temperatures to determine its long-term stability in solution. Glucagon nanogels were stable up to at least 5 months by size uniformity when stored at -20 °C and 4 °C, up to 5 days at 25 °C, and less than 12 hours at 37 °C. When glucagon stability was studied by either HPLC or thioflavin T assays, the glucagon was intact for at least 5 months at -20 °C and 4 °C within the nanoparticles at -20 °C and 4 °C and up to 2 days at 25 °C. Additionally, the glucagon nanogels were studied for toxicity and efficacy using various assays in vitro. The findings indicate that the nanogels were nontoxic to fibroblast cells and nonhemolytic to red blood cells. The glucagon in the nanogels was as active as glucagon alone. These results demonstrate the utility of trehalose nanogels towards a glucagon formulation with improved stability and solubility in aqueous solutions, particularly useful for storage at cold temperatures.
RESUMO
While regular physical activity is a cornerstone of health, wellness, and vitality, the impact of endurance exercise training on molecular signaling within and across tissues remains to be delineated. The Molecular Transducers of Physical Activity Consortium (MoTrPAC) was established to characterize molecular networks underlying the adaptive response to exercise. Here, we describe the endurance exercise training studies undertaken by the Preclinical Animal Sites Studies component of MoTrPAC, in which we sought to develop and implement a standardized endurance exercise protocol in a large cohort of rats. To this end, Adult (6-mo) and Aged (18-mo) female (n = 151) and male (n = 143) Fischer 344 rats were subjected to progressive treadmill training (5 d/wk, â¼70%-75% VO2max) for 1, 2, 4, or 8 wk; sedentary rats were studied as the control group. A total of 18 solid tissues, as well as blood, plasma, and feces, were collected to establish a publicly accessible biorepository and for extensive omics-based analyses by MoTrPAC. Treadmill training was highly effective, with robust improvements in skeletal muscle citrate synthase activity in as little as 1-2 wk and improvements in maximum run speed and maximal oxygen uptake by 4-8 wk. For body mass and composition, notable age- and sex-dependent responses were observed. This work in mature, treadmill-trained rats represents the most comprehensive and publicly accessible tissue biorepository, to date, and provides an unprecedented resource for studying temporal-, sex-, and age-specific responses to endurance exercise training in a preclinical rat model.
Assuntos
Adaptação Fisiológica , Envelhecimento , Condicionamento Físico Animal , Ratos Endogâmicos F344 , Animais , Masculino , Feminino , Condicionamento Físico Animal/fisiologia , Adaptação Fisiológica/fisiologia , Ratos , Envelhecimento/fisiologia , Resistência Física/fisiologia , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiologia , Treino AeróbicoRESUMO
Background: Physical activity has been associated with preventing the development of type 2 diabetes and atherosclerotic cardiovascular disease. However, our understanding of the precise molecular mechanisms underlying these effects remains incomplete and good biomarkers to objectively assess physical activity are lacking. Methods: We analyzed 3072 serum proteins in 26 men, normal weight or overweight, undergoing 12 weeks of a combined strength and endurance exercise intervention. We estimated insulin sensitivity with hyperinsulinemic euglycemic clamp, maximum oxygen uptake, muscle strength, and used MRI/MRS to evaluate body composition and organ fat depots. Muscle and subcutaneous adipose tissue biopsies were used for mRNA sequencing. Additional association analyses were performed in samples from up to 47,747 individuals in the UK Biobank, as well as using two-sample Mendelian randomization and mice models. Results: Following 12 weeks of exercise intervention, we observed significant changes in 283 serum proteins. Notably, 66 of these proteins were elevated in overweight men and positively associated with liver fat before the exercise regimen, but were normalized after exercise. Furthermore, for 19.7 and 12.1% of the exercise-responsive proteins, corresponding changes in mRNA expression levels in muscle and fat, respectively, were shown. The protein CD300LG displayed consistent alterations in blood, muscle, and fat. Serum CD300LG exhibited positive associations with insulin sensitivity, and to angiogenesis-related gene expression in both muscle and fat. Furthermore, serum CD300LG was positively associated with physical activity and negatively associated with glucose levels in the UK Biobank. In this sample, the association between serum CD300LG and physical activity was significantly stronger in men than in women. Mendelian randomization analysis suggested potential causal relationships between levels of serum CD300LG and fasting glucose, 2 hr glucose after an oral glucose tolerance test, and HbA1c. Additionally, Cd300lg responded to exercise in a mouse model, and we observed signs of impaired glucose tolerance in male, but not female, Cd300lg knockout mice. Conclusions: Our study identified several novel proteins in serum whose levels change in response to prolonged exercise and were significantly associated with body composition, liver fat, and glucose homeostasis. Serum CD300LG increased with physical activity and is a potential causal link to improved glucose levels. CD300LG may be a promising exercise biomarker and a therapeutic target in type 2 diabetes. Funding: South-Eastern Norway Regional Health Authority, Simon Fougners Fund, Diabetesforbundet, Johan Selmer Kvanes' legat til forskning og bekjempelse av sukkersyke. The UK Biobank resource reference 53641. Australian National Health and Medical Research Council Investigator Grant (APP2017942). Australian Research Council Discovery Early Career Award (DE220101226). Research Council of Norway (Project grant: 325640 and Mobility grant: 287198). The Medical Student Research Program at the University of Oslo. Novo Nordisk Fonden Excellence Emerging Grant in Endocrinology and Metabolism 2023 (NNF23OC0082123). Clinical trial number: clinicaltrials.gov: NCT01803568.
Assuntos
Exercício Físico , Homeostase , Humanos , Masculino , Animais , Exercício Físico/fisiologia , Camundongos , Pessoa de Meia-Idade , Proteômica , Adulto , Resistência à Insulina , Feminino , Glucose/metabolismo , Biomarcadores/sangue , Proteínas Sanguíneas/metabolismo , Proteínas Sanguíneas/análise , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/sangue , Músculo Esquelético/metabolismo , Sobrepeso/metabolismo , Sobrepeso/sangue , Glicemia/metabolismoRESUMO
Inter-organ communication is a vital process to maintain physiologic homeostasis, and its dysregulation contributes to many human diseases. Given that circulating bioactive factors are stable in serum, occur naturally, and are easily assayed from blood, they present obvious focal molecules for therapeutic intervention and biomarker development. Recently, studies have shown that secreted proteins mediating inter-tissue signaling could be identified by 'brute force' surveys of all genes within RNA-sequencing measures across tissues within a population. Expanding on this intuition, we reasoned that parallel strategies could be used to understand how individual genes mediate signaling across metabolic tissues through correlative analyses of gene variation between individuals. Thus, comparison of quantitative levels of gene expression relationships between organs in a population could aid in understanding cross-organ signaling. Here, we surveyed gene-gene correlation structure across 18 metabolic tissues in 310 human individuals and 7 tissues in 103 diverse strains of mice fed a normal chow or high-fat/high-sucrose (HFHS) diet. Variation of genes such as FGF21, ADIPOQ, GCG, and IL6 showed enrichments which recapitulate experimental observations. Further, similar analyses were applied to explore both within-tissue signaling mechanisms (liver PCSK9) and genes encoding enzymes producing metabolites (adipose PNPLA2), where inter-individual correlation structure aligned with known roles for these critical metabolic pathways. Examination of sex hormone receptor correlations in mice highlighted the difference of tissue-specific variation in relationships with metabolic traits. We refer to this resource as gene-derived correlations across tissues (GD-CAT) where all tools and data are built into a web portal enabling users to perform these analyses without a single line of code (gdcat.org). This resource enables querying of any gene in any tissue to find correlated patterns of genes, cell types, pathways, and network architectures across metabolic organs.
Assuntos
Pró-Proteína Convertase 9 , Transdução de Sinais , Humanos , Animais , Camundongos , Homeostase , AdiposidadeRESUMO
The dynamin-related guanosine triphosphatase, Drp1 (encoded by Dnm1l), plays a central role in mitochondrial fission and is requisite for numerous cellular processes; however, its role in muscle metabolism remains unclear. Here, we show that, among human tissues, the highest number of gene correlations with DNM1L is in skeletal muscle. Knockdown of Drp1 (Drp1-KD) promoted mitochondrial hyperfusion in the muscle of male mice. Reduced fatty acid oxidation and impaired insulin action along with increased muscle succinate was observed in Drp1-KD muscle. Muscle Drp1-KD reduced complex II assembly and activity as a consequence of diminished mitochondrial translocation of succinate dehydrogenase assembly factor 2 (Sdhaf2). Restoration of Sdhaf2 normalized complex II activity, lipid oxidation, and insulin action in Drp1-KD myocytes. Drp1 is critical in maintaining mitochondrial complex II assembly, lipid oxidation, and insulin sensitivity, suggesting a mechanistic link between mitochondrial morphology and skeletal muscle metabolism, which is clinically relevant in combatting metabolic-related diseases.
Assuntos
Insulinas , Succinato Desidrogenase , Animais , Humanos , Masculino , Camundongos , Insulinas/metabolismo , Lipídeos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Músculo Esquelético/metabolismo , Succinato Desidrogenase/metabolismoRESUMO
Mitochondria have diverse functions critical to whole-body metabolic homeostasis. Endurance training alters mitochondrial activity, but systematic characterization of these adaptations is lacking. Here, the Molecular Transducers of Physical Activity Consortium mapped the temporal, multi-omic changes in mitochondrial analytes across 19 tissues in male and female rats trained for 1, 2, 4, or 8 weeks. Training elicited substantial changes in the adrenal gland, brown adipose, colon, heart, and skeletal muscle. The colon showed non-linear response dynamics, whereas mitochondrial pathways were downregulated in brown adipose and adrenal tissues. Protein acetylation increased in the liver, with a shift in lipid metabolism, whereas oxidative proteins increased in striated muscles. Exercise-upregulated networks were downregulated in human diabetes and cirrhosis. Knockdown of the central network protein 17-beta-hydroxysteroid dehydrogenase 10 (HSD17B10) elevated oxygen consumption, indicative of metabolic stress. We provide a multi-omic, multi-tissue, temporal atlas of the mitochondrial response to exercise training and identify candidates linked to mitochondrial dysfunction.
Assuntos
Mitocôndrias , Condicionamento Físico Animal , Animais , Masculino , Feminino , Mitocôndrias/metabolismo , Ratos , Músculo Esquelético/metabolismo , Humanos , Ratos Sprague-Dawley , Tecido Adiposo Marrom/metabolismo , Glândulas Suprarrenais/metabolismo , MultiômicaRESUMO
Subcutaneous white adipose tissue (scWAT) is a dynamic storage and secretory organ that regulates systemic homeostasis, yet the impact of endurance exercise training (ExT) and sex on its molecular landscape is not fully established. Utilizing an integrative multi-omics approach, and leveraging data generated by the Molecular Transducers of Physical Activity Consortium (MoTrPAC), we show profound sexual dimorphism in the scWAT of sedentary rats and in the dynamic response of this tissue to ExT. Specifically, the scWAT of sedentary females displays -omic signatures related to insulin signaling and adipogenesis, whereas the scWAT of sedentary males is enriched in terms related to aerobic metabolism. These sex-specific -omic signatures are preserved or amplified with ExT. Integration of multi-omic analyses with phenotypic measures identifies molecular hubs predicted to drive sexually distinct responses to training. Overall, this study underscores the powerful impact of sex on adipose tissue biology and provides a rich resource to investigate the scWAT response to ExT.
Assuntos
Tecido Adiposo Branco , Condicionamento Físico Animal , Caracteres Sexuais , Gordura Subcutânea , Animais , Masculino , Feminino , Ratos , Tecido Adiposo Branco/metabolismo , Gordura Subcutânea/metabolismo , Adipogenia , Ratos Sprague-Dawley , MultiômicaRESUMO
Elevated fatty acids promote inflammation and insulin resistance. In this issue of Cell Metabolism, Koves et al. (2008) explore a novel paradigm suggesting that beta-oxidation of fatty acids exceeding the capacity of the tricarboxylic acid cycle yields incomplete fat oxidation and mitochondrial distress, obligatory events in the pathogenesis of insulin resistance.
Assuntos
Resistência à Insulina , Mitocôndrias/metabolismo , Animais , Ciclo do Ácido Cítrico , Ácidos Graxos/metabolismo , Modelos Biológicos , OxirreduçãoRESUMO
A decrease in bone mineral density during menopause is accompanied by an increase in adipocytes in the bone marrow space. Ovariectomy also leads to accumulation of fat in the bone marrow. Herein we show increased lipid accumulation in bone marrow from estrogen receptor alpha (ERα) knockout (ERαKO) mice compared to wild-type (WT) mice or estrogen receptor beta (ERß) knockout (ERßKO) mice. Similarly, bone marrow cells from ERαKO mice differentiated to adipocytes in culture also have increased lipid accumulation compared to cells from WT mice or ERßKO mice. Analysis of individual adipocytes shows that WT mice have fewer, but larger, lipid droplets per cell than adipocytes from ERαKO or ERßKO animals. Furthermore, higher levels of adipose triglyceride lipase (ATGL) protein in WT adipocytes correlate with increased lipolysis and fewer lipid droplets per cell and treatment with 17ß-estradiol (E2) potentiates this response. In contrast, cells from ERαKO mice display higher perilipin protein levels, promoting lipogenesis. Together these results demonstrate that E2 signals via ERα to regulate lipid droplet size and total lipid accumulation in the bone marrow space in vivo.
Assuntos
Medula Óssea/metabolismo , Proteínas de Transporte/metabolismo , Receptor alfa de Estrogênio/metabolismo , Lipase/metabolismo , Lipogênese , Lipólise , Fosfoproteínas/metabolismo , Adipócitos/metabolismo , Adipócitos/patologia , Adiposidade , Animais , Feminino , Fêmur/metabolismo , Humanos , Masculino , Camundongos , Camundongos Knockout , Osteoporose Pós-Menopausa/metabolismo , Perilipina-1RESUMO
Mitochondria are adaptable organelles with diverse cellular functions critical to whole-body metabolic homeostasis. While chronic endurance exercise training is known to alter mitochondrial activity, these adaptations have not yet been systematically characterized. Here, the Molecular Transducers of Physical Activity Consortium (MoTrPAC) mapped the longitudinal, multi-omic changes in mitochondrial analytes across 19 tissues in male and female rats endurance trained for 1, 2, 4 or 8 weeks. Training elicited substantial changes in the adrenal gland, brown adipose, colon, heart and skeletal muscle, while we detected mild responses in the brain, lung, small intestine and testes. The colon response was characterized by non-linear dynamics that resulted in upregulation of mitochondrial function that was more prominent in females. Brown adipose and adrenal tissues were characterized by substantial downregulation of mitochondrial pathways. Training induced a previously unrecognized robust upregulation of mitochondrial protein abundance and acetylation in the liver, and a concomitant shift in lipid metabolism. The striated muscles demonstrated a highly coordinated response to increase oxidative capacity, with the majority of changes occurring in protein abundance and post-translational modifications. We identified exercise upregulated networks that are downregulated in human type 2 diabetes and liver cirrhosis. In both cases HSD17B10, a central dehydrogenase in multiple metabolic pathways and mitochondrial tRNA maturation, was the main hub. In summary, we provide a multi-omic, cross-tissue atlas of the mitochondrial response to training and identify candidates for prevention of disease-associated mitochondrial dysfunction.