RESUMO
Background and Aims: Population aging is fueling an epidemic of age-related chronic diseases. Managing risk factors and lifestyle interventions have proven effective in disease prevention. Epidemiological studies have linked markers of poor hydration with higher risk of chronic diseases and premature mortality. Many individuals do not adhere to recommended hydration levels and could benefit from improved hydration habits. Our study evaluates the use of electronic medical records to confirm the relationship between inadequate hydration and the risk of chronic diseases, which may inform hydration-focused interventions in general healthcare. Methods: We analyzed 20-year electronic medical records for 411,029 adults from Israel's Leumit Healthcare Services. Hydration status was assessed using serum sodium and tonicity. We included adults without significant chronic diseases or water balance issues, defined as having normal serum sodium (135-146 mmol/l) and no diagnosis of diabetes. We used Cox proportional hazards models, adjusted for age, to assess the risk of developing hypertension and heart failure. Results: Our findings showed an increased risk of hypertension with elevated serum sodium levels: a 12% rise for the 140-142 mmol/l group and 30% for levels above 143 mmol/l (HR1.30, 95%CI:1.26-1.34). Tonicity over 287 mosmol/kg was associated with a 19% increased risk of hypertension (HR1.19, 95%CI:1.17-1.22). The risk of heart failure also increased, reaching 20% for sodium levels above 143 mmol/l (HR1.20,95%CI:1.12-1.29) and 16% for tonicity above 289 mosmol/kg (HR1.16, 95%CI: 1.10-1.22). The association between sodium and hypertension was observed across genders, while the risk of heart failure was more pronounced in females. Within the healthy Leumit cohort, 19% had serum sodium levels within the 143-146 mmol/l range, and 39% were in the 140-142 mmol/l range. Conclusions: Data analysis from electronic medical records identified a link between serum sodium of 140 mmol/l and above and increased risk of hypertension and heart failure in the general Israeli population. Identifying individuals with high-normal sodium values in healthcare records could guide improvements in hydration habits, potentially leading to better health outcomes.
RESUMO
Body water balance is determined by fundamental homeostatic mechanisms that maintain stable volume, osmolality and the composition of extracellular and intracellular fluids. Water balance is maintained by multiple mechanisms that continuously match water losses through urine, the skin, the gastrointestinal tract and respiration with water gains achieved through drinking, eating and metabolic water production. Hydration status is determined by the state of the water balance. Underhydration occurs when a decrease in body water availability, due to high losses or low gains, stimulates adaptive responses within the water balance network that are aimed at decreasing losses and increasing gains. This stimulation is also accompanied by cardiovascular adjustments. Epidemiological and experimental studies have linked markers of low fluid intake and underhydration - such as increased plasma concentration of vasopressin and sodium, as well as elevated urine osmolality - with an increased risk of new-onset chronic diseases, accelerated aging and premature mortality, suggesting that persistent activation of adaptive responses may be detrimental to long-term health outcomes. The causative nature of these associations is currently being tested in interventional trials. Understanding of the physiological responses to underhydration may help to identify possible mechanisms that underlie potential adverse, long-term effects of underhydration and inform future research to develop preventative and treatment approaches to the optimization of hydration status.
RESUMO
The increasing incidence of cardiovascular disease (CVD) has led to a significant ongoing need to address this surgically through coronary artery bypass grafting (CABG) and percutaneous coronary interventions (PCI). From this, there continues to be a substantial burden of mortality and morbidity due to complications arising from endothelial damage, resulting in restenosis. Whilst mast cells (MC) have been shown to have a causative role in atherosclerosis and other vascular diseases, including restenosis due to vein engraftment; here, we demonstrate their rapid response to arterial wire injury, recapitulating the endothelial damage seen in PCI procedures. Using wild-type mice, we demonstrate accumulation of MC in the femoral artery post-acute wire injury, with rapid activation and degranulation, resulting in neointimal hyperplasia, which was not observed in MC-deficient KitW-sh/W-sh mice. Furthermore, neutrophils, macrophages, and T cells were abundant in the wild-type mice area of injury but reduced in the KitW-sh/W-sh mice. Following bone-marrow-derived MC (BMMC) transplantation into KitW-sh/W-sh mice, not only was the neointimal hyperplasia induced, but the neutrophil, macrophage, and T-cell populations were also present in these transplanted mice. To demonstrate the utility of MC as a target for therapy, we administered the MC stabilizing drug, disodium cromoglycate (DSCG) immediately following arterial injury and were able to show a reduction in neointimal hyperplasia in wild-type mice. These studies suggest a critical role for MC in inducing the conditions and coordinating the detrimental inflammatory response seen post-endothelial injury in arteries undergoing revascularization procedures, and by targeting the rapid MC degranulation immediately post-surgery with DSCG, this restenosis may become a preventable clinical complication.
Assuntos
Aterosclerose , Intervenção Coronária Percutânea , Lesões do Sistema Vascular , Animais , Camundongos , Hiperplasia , Mastócitos , Artérias , Constrição PatológicaRESUMO
BACKGROUND: It is known that some people age faster than others, some people live into old age disease-free, while others develop age-related chronic diseases. With a rapidly aging population and an emerging chronic diseases epidemic, finding mechanisms and implementing preventive measures that could slow down the aging process has become a new challenge for biomedical research and public health. In mice, lifelong water restriction shortens the lifespan and promotes degenerative changes. Here, we test the hypothesis that optimal hydration may slow down the aging process in humans. METHODS: We performed a cohort analysis of data from the Atherosclerosis Risk in Communities study with middle-age enrollment (45-66 years, n = 15,752) and 25 years follow-up. We used serum sodium, as a proxy for hydration habits. To estimate the relative speed of aging, we calculated the biological age (BA) from age-dependent biomarkers and assessed risks of chronic diseases and premature mortality. FINDINGS: The analysis showed that middle age serum sodium >142 mmol/l is associated with a 39% increased risk to develop chronic diseases (hazard ratio [HR] = 1.39, 95% confidence interval [CI]:1.18-1.63) and >144 mmol/l with 21% elevated risk of premature mortality (HR = 1.21, 95% CI:1.02-1.45). People with serum sodium >142 mmol/l had up to 50% higher odds to be older than their chronological age (OR = 1.50, 95% CI:1.14-1.96). A higher BA was associated with an increased risk of chronic diseases (HR = 1.70, 95% CI:1.50-1.93) and premature mortality (HR = 1.59, 95% CI 1.39-1.83). INTERPRETATION: People whose middle-age serum sodium exceeds 142 mmol/l have increased risk to be biologically older, develop chronic diseases and die at younger age. Intervention studies are needed to confirm the link between hydration and aging. FUNDING: This work was funded by Intramural Research program of the National Heart, Lung, and Blood Institute (NHLBI). The ARIC study has been funded in whole or in part with federal funds from the NHLBI; the National Institutes of Health (NIH); and the Department of Health and Human Services.
Assuntos
Envelhecimento , Mortalidade Prematura , Pessoa de Meia-Idade , Humanos , Animais , Camundongos , Idoso , Fatores de Risco , Doença Crônica , SódioRESUMO
AIMS: With increasing prevalence of heart failure (HF) owing to the ageing population, identification of modifiable risk factors is important. In a mouse model, chronic hypohydration induced by lifelong water restriction promotes cardiac fibrosis. Hypohydration elevates serum sodium. Here, we evaluate the association of serum sodium at middle age as a measure of hydration habits with risk to develop HF. METHODS AND RESULTS: We analysed data from Atherosclerosis Risk in Communities study with middle age enrolment (45-66 years) and 25 years of follow-up. Participants without water balance dysregulation were selected: serum sodium within normal range (135-146â mmol/L), not diabetic, not obese and free of HF at baseline (N = 11 814). In time-to-event analysis, HF risk was increased by 39% if middle age serum sodium exceeded 143â mmol/L corresponding to 1% body weight water deficit [hazard ratio 1.39, 95% confidence interval (CI) 1.14-1.70]. In a retrospective case-control analysis performed on 70- to 90-year-old attendees of Visit 5 (N = 4961), serum sodium of 142.5-143â mmol/L was associated with 62% increase in odds of left ventricular hypertrophy (LVH) diagnosis [odds ratio (OR) 1.62, 95% CI 1.03-2.55]. Serum sodium above 143â mmol/L was associated with 107% increase in odds of LVH (OR 2.07, 95% CI 1.30-3.28) and 54% increase in odds of HF (OR 1.54, 95% CI 1.06-2.23). As a result, prevalence of HF and LVH was increased among 70- to 90-year-old participants with higher middle age serum sodium. CONCLUSION: Middle age serum sodium above 142â mmol is a risk factor for LVH and HF. Maintaining good hydration throughout life may slow down decline in cardiac function and decrease prevalence of HF.
Assuntos
Insuficiência Cardíaca , Animais , Insuficiência Cardíaca/epidemiologia , Insuficiência Cardíaca/etiologia , Humanos , Hipertrofia Ventricular Esquerda/diagnóstico , Camundongos , Valores de Referência , Estudos Retrospectivos , Sódio , ÁguaRESUMO
Human induced pluripotent stem cell (iPSC) technology has opened exciting opportunities for stem-cell-based therapy. However, its wide adoption is precluded by several challenges including low reprogramming efficiency and potential for malignant transformation. Better understanding of the molecular mechanisms of the changes that cells undergo during reprograming is needed to improve iPSCs generation efficiency and to increase confidence for their clinical use safety. Here, we find that dominant negative mutations in STAT3 in patients with autosomal-dominant hyper IgE (Job's) syndrome (AD-HIES) result in greatly reduced reprograming efficiency of primary skin fibroblasts derived from skin biopsies. Analysis of normal skin fibroblasts revealed upregulation and phosphorylation of endogenous signal transducer and activator of transcription 3 (STAT3) and its binding to the NANOG promoter following transduction with OKSM factors. This coincided with upregulation of NANOG and appearance of cells expressing pluripotency markers. Upregulation of NANOG and number of pluripotent cells were greatly reduced throughout the reprograming process of AD-HIES fibroblasts that was restored by over-expression of functional STAT3. NANOGP8, the human-specific NANOG retrogene that is often expressed in human cancers, was also induced during reprogramming, to very low but detectable levels, in a STAT3-dependent manner. Our study revealed the critical role of endogenous STAT3 in facilitating reprogramming of human somatic cells.
Assuntos
Suscetibilidade a Doenças , Imunoglobulina E/sangue , Síndrome de Job/etiologia , Síndrome de Job/metabolismo , Mutação , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo , Adolescente , Adulto , Idoso , Alelos , Substituição de Aminoácidos , Células Cultivadas , Criança , Fibroblastos/metabolismo , Predisposição Genética para Doença , Genótipo , Humanos , Imunoglobulina E/imunologia , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Mutação com Perda de Função , Pessoa de Meia-Idade , Adulto JovemRESUMO
There are more than 7000 described rare diseases, most lacking specific treatment. Autosomal-dominant hyper-IgE syndrome (AD-HIES, also known as Job's syndrome) is caused by mutations in STAT3. These patients present with immunodeficiency accompanied by severe nonimmunological features, including skeletal, connective tissue, and vascular abnormalities, poor postinfection lung healing, and subsequent pulmonary failure. No specific therapies are available for these abnormalities. Here, we investigated underlying mechanisms in order to identify therapeutic targets. Histological analysis of skin wounds demonstrated delayed granulation tissue formation and vascularization during skin-wound healing in AD-HIES patients. Global gene expression analysis in AD-HIES patient skin fibroblasts identified deficiencies in a STAT3-controlled transcriptional network regulating extracellular matrix (ECM) remodeling and angiogenesis, with hypoxia-inducible factor 1α (HIF-1α) being a major contributor. Consistent with this, histological analysis of skin wounds and coronary arteries from AD-HIES patients showed decreased HIF-1α expression and revealed abnormal organization of the ECM and altered formation of the coronary vasa vasorum. Disease modeling using cell culture and mouse models of angiogenesis and wound healing confirmed these predicted deficiencies and demonstrated therapeutic benefit of HIF-1α-stabilizing drugs. The study provides mechanistic insights into AD-HIES pathophysiology and suggests potential treatment options for this rare disease.
Assuntos
Matriz Extracelular/metabolismo , Síndrome de Job/metabolismo , Neovascularização Fisiológica , Pele/metabolismo , Cicatrização , Ferimentos e Lesões/metabolismo , Animais , Matriz Extracelular/genética , Matriz Extracelular/patologia , Feminino , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Síndrome de Job/genética , Síndrome de Job/patologia , Masculino , Camundongos , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo , Pele/irrigação sanguínea , Pele/patologia , Ferimentos e Lesões/genética , Ferimentos e Lesões/patologiaRESUMO
RIPK1 is a key regulator of innate immune signalling pathways. To ensure an optimal inflammatory response, RIPK1 is regulated post-translationally by well-characterized ubiquitylation and phosphorylation events, as well as by caspase-8-mediated cleavage1-7. The physiological relevance of this cleavage event remains unclear, although it is thought to inhibit activation of RIPK3 and necroptosis8. Here we show that the heterozygous missense mutations D324N, D324H and D324Y prevent caspase cleavage of RIPK1 in humans and result in an early-onset periodic fever syndrome and severe intermittent lymphadenopathy-a condition we term 'cleavage-resistant RIPK1-induced autoinflammatory syndrome'. To define the mechanism for this disease, we generated a cleavage-resistant Ripk1D325A mutant mouse strain. Whereas Ripk1-/- mice died postnatally from systemic inflammation, Ripk1D325A/D325A mice died during embryogenesis. Embryonic lethality was completely prevented by the combined loss of Casp8 and Ripk3, but not by loss of Ripk3 or Mlkl alone. Loss of RIPK1 kinase activity also prevented Ripk1D325A/D325A embryonic lethality, although the mice died before weaning from multi-organ inflammation in a RIPK3-dependent manner. Consistently, Ripk1D325A/D325A and Ripk1D325A/+ cells were hypersensitive to RIPK3-dependent TNF-induced apoptosis and necroptosis. Heterozygous Ripk1D325A/+ mice were viable and grossly normal, but were hyper-responsive to inflammatory stimuli in vivo. Our results demonstrate the importance of caspase-mediated RIPK1 cleavage during embryonic development and show that caspase cleavage of RIPK1 not only inhibits necroptosis but also maintains inflammatory homeostasis throughout life.
Assuntos
Caspase 8/metabolismo , Doenças Hereditárias Autoinflamatórias/metabolismo , Mutação , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo , Animais , Caspase 3/metabolismo , Feminino , Doenças Hereditárias Autoinflamatórias/genética , Doenças Hereditárias Autoinflamatórias/patologia , Humanos , MAP Quinase Quinase Quinases/genética , MAP Quinase Quinase Quinases/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Linhagem , Proteína Serina-Treonina Quinases de Interação com Receptores/deficiência , Proteína Serina-Treonina Quinases de Interação com Receptores/genéticaRESUMO
With increased life expectancy worldwide, there is an urgent need for improving preventive measures that delay the development of age-related degenerative diseases. Here, we report evidence from mouse and human studies that this goal can be achieved by maintaining optimal hydration throughout life. We demonstrate that restricting the amount of drinking water shortens mouse lifespan with no major warning signs up to 14 months of life, followed by sharp deterioration. Mechanistically, water restriction yields stable metabolism remodeling toward metabolic water production with greater food intake and energy expenditure, an elevation of markers of inflammation and coagulation, accelerated decline of neuromuscular coordination, renal glomerular injury, and the development of cardiac fibrosis. In humans, analysis of data from the Atherosclerosis Risk in Communities (ARIC) study revealed that hydration level, assessed at middle age by serum sodium concentration, is associated with markers of coagulation and inflammation and predicts the development of many age-related degenerative diseases 24 years later. The analysis estimates that improving hydration throughout life may greatly decrease the prevalence of degenerative diseases, with the most profound effect on dementia, heart failure (HF), and chronic lung disease (CLD), translating to the development of these diseases in 3 million fewer people in the United States alone.
Assuntos
Envelhecimento/metabolismo , Vida , Equilíbrio Hidroeletrolítico , Injúria Renal Aguda , Animais , Aterosclerose/metabolismo , Biomarcadores/sangue , Doença Crônica , Desidratação/epidemiologia , Desidratação/metabolismo , Demência/metabolismo , Fibrose , Insuficiência Cardíaca/metabolismo , Humanos , Inflamação , Pneumopatias/metabolismo , Masculino , Camundongos , Doenças Neurodegenerativas/metabolismo , Estado de Hidratação do Organismo , Análise de Regressão , Fatores de Risco , Sódio/sangueRESUMO
OBJECTIVE: Serum sodium concentration is maintained by osmoregulation within normal range of 135 to 145 mmol/L. Previous analysis of data from the ARIC study (Atherosclerosis Risk in Communities) showed association of serum sodium with the 10-year risk scores of coronary heart disease and stroke. Current study evaluated the association of within-normal-range serum sodium with cardiovascular risk factors. APPROACH AND RESULTS: Only participants who did not take cholesterol or blood pressure medications and had sodium within normal 135 to 145 mmol/L range were included (n=8615), and the cohort was stratified based on race, sex, and smoking status. Multiple linear regression analysis of data from ARIC study was performed, with adjustment for age, blood glucose, insulin, glomerular filtration rate, body mass index, waist to hip ratio, and calorie intake. The analysis showed positive associations with sodium of total cholesterol, low-density lipoprotein cholesterol, and total cholesterol to high-density lipoprotein cholesterol ratio; apolipoprotein B; and systolic and diastolic blood pressure. Increases in lipids and blood pressure associated with 10 mmol/L increase in sodium are similar to the increases associated with 7 to 10 years of aging. Analysis of sodium measurements made 3 years apart demonstrated that it is stable within 2 to 3 mmol/L, explaining its association with long-term health outcomes. Furthermore, elevated sodium promoted lipid accumulation in cultured adipocytes, suggesting direct causative effects on lipid metabolism. CONCLUSIONS: Serum sodium concentration is a cardiovascular risk factor even within the normal reference range. Thus, decreasing sodium to the lower end of the normal range by modification of water and salt intake is a personalizable strategy for decreasing cardiovascular risks.
Assuntos
Pressão Sanguínea , Doenças Cardiovasculares/epidemiologia , Lipídeos/sangue , Sódio/sangue , Células 3T3-L1 , Adipócitos/metabolismo , Animais , Biomarcadores/sangue , Índice de Massa Corporal , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/fisiopatologia , Estudos Transversais , Feminino , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Valores de Referência , Estudos Retrospectivos , Fatores de Risco , Fatores de Tempo , Estados Unidos/epidemiologia , Relação Cintura-QuadrilRESUMO
ACDC (arterial calcification due to deficiency of CD73) is an autosomal recessive disease resulting from loss-of-function mutations in NT5E, which encodes CD73, a 5'-ectonucleotidase that converts extracellular adenosine monophosphate to adenosine. ACDC patients display progressive calcification of lower extremity arteries, causing limb ischemia. Tissue-nonspecific alkaline phosphatase (TNAP), which converts pyrophosphate (PPi) to inorganic phosphate (Pi), and extracellular purine metabolism play important roles in other inherited forms of vascular calcification. Compared to cells from healthy subjects, induced pluripotent stem cell-derived mesenchymal stromal cells (iMSCs) from ACDC patients displayed accelerated calcification and increased TNAP activity when cultured under conditions that promote osteogenesis. TNAP activity generated adenosine in iMSCs derived from ACDC patients but not in iMSCs from control subjects, which have CD73. In response to osteogenic stimulation, ACDC patient-derived iMSCs had decreased amounts of the TNAP substrate PPi, an inhibitor of extracellular matrix calcification, and exhibited increased activation of AKT, mechanistic target of rapamycin (mTOR), and the 70-kDa ribosomal protein S6 kinase (p70S6K), a pathway that promotes calcification. In vivo, teratomas derived from ACDC patient cells showed extensive calcification and increased TNAP activity. Treating mice bearing these teratomas with an A2b adenosine receptor agonist, the mTOR inhibitor rapamycin, or the bisphosphonate etidronate reduced calcification. These results show that an increase of TNAP activity in ACDC contributes to ectopic calcification by disrupting the extracellular balance of PPi and Pi and identify potential therapeutic targets for ACDC.
Assuntos
Fosfatase Alcalina/metabolismo , Doenças Genéticas Inatas/enzimologia , Células-Tronco Pluripotentes Induzidas/enzimologia , Células-Tronco Mesenquimais/enzimologia , Transdução de Sinais , Calcificação Vascular/enzimologia , 5'-Nucleotidase/deficiência , Adenosina/genética , Adenosina/metabolismo , Fosfatase Alcalina/genética , Animais , Proteínas Ligadas por GPI/deficiência , Doenças Genéticas Inatas/genética , Doenças Genéticas Inatas/patologia , Humanos , Células-Tronco Pluripotentes Induzidas/patologia , Células-Tronco Mesenquimais/patologia , Camundongos , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Quinases S6 Ribossômicas 70-kDa/genética , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo , Calcificação Vascular/genética , Calcificação Vascular/patologiaRESUMO
Cardiovascular diseases (CVDs) are a leading health problem worldwide. Epidemiologic studies link high salt intake and conditions predisposing to dehydration such as low water intake, diabetes and old age to increased risk of CVD. Previously, we demonstrated that elevation of extracellular sodium, which is a common consequence of these conditions, stimulates production by endothelial cells of clotting initiator, von Willebrand Factor, increases its level in blood and promotes thrombogenesis. In present study, by PCR array, using human umbilical vein endothelial cells (HUVECs), we analyzed the effect of high NaCl on 84 genes related to endothelial cell biology. The analysis showed that the affected genes regulate many aspects of endothelial cell biology including cell adhesion, proliferation, leukocyte and lymphocyte activation, coagulation, angiogenesis and inflammatory response. The genes whose expression increased the most were adhesion molecules VCAM1 and E-selectin and the chemoattractant MCP-1. These are key participants in the leukocyte adhesion and transmigration that play a major role in the inflammation and pathophysiology of CVD, including atherosclerosis. Indeed, high NaCl increased adhesion of mononuclear cells and their transmigration through HUVECs monolayers. In mice, mild water restriction that elevates serum sodium by 5 mmol/l, increased VCAM1, E-selectin and MCP-1 expression in mouse tissues, accelerated atherosclerotic plaque formation in aortic root and caused thickening or walls of coronary arteries. Multivariable linear regression analysis of clinical data from the Atherosclerosis Risk in Communities Study (n=12779) demonstrated that serum sodium is a significant predictor of 10 Years Risk of coronary heart disease. These findings indicate that elevation of extracellular sodium within the physiological range is accompanied by vascular changes that facilitate development of CVD. The findings bring attention to serum sodium as a risk factor for CVDs and give additional support to recommendations for dietary salt restriction and adequate water intake as preventives of CVD.
Assuntos
Aterosclerose/sangue , Aterosclerose/patologia , Desidratação/sangue , Células Endoteliais da Veia Umbilical Humana/metabolismo , Inflamação/sangue , Transdução de Sinais , Sódio/sangue , Animais , Apolipoproteínas E/deficiência , Apolipoproteínas E/metabolismo , Aterosclerose/genética , Adesão Celular/efeitos dos fármacos , Células Cultivadas , Meios de Cultura/química , Humanos , Inflamação/genética , Mediadores da Inflamação/metabolismo , Modelos Lineares , Masculino , Camundongos , Análise Multivariada , Características de Residência , Fatores de Risco , Cloreto de Sódio na Dieta/efeitos adversos , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/genéticaRESUMO
Hypercoagulability increases risk of thrombi that cause cardiovascular events. Here we identify plasma sodium concentration as a factor that modulates blood coagulability by affecting the production of von Willebrand factor (vWF), a key initiator of the clotting cascade. We find that elevation of salt over a range from the lower end of what is normal in blood to the level of severe hypernatremia reversibly increases vWF mRNA in endothelial cells in culture and the rate of vWF secretion from them. The high NaCl increases expression of tonicity-regulated transcription factor NFAT5 and its binding to promoter of vWF gene, suggesting involvement of hypertonic signaling in vWF up-regulation. To elevate NaCl in vivo, we modeled mild dehydration, subjecting mice to water restriction (WR) by feeding them with gel food containing 30% water. Such WR elevates blood sodium from 145.1 ± 0.5 to 150.2 ± 1.3 mmol/L and activates hypertonic signaling, evidenced from increased expression of NFAT5 in tissues. WR increases vWF mRNA in liver and lung and raises vWF protein in blood. Immunostaining of liver revealed increased production of vWF protein by endothelium and increased number of microthrombi inside capillaries. WR also increases blood level of D-dimer, indicative of ongoing coagulation and thrombolysis. Multivariate regression analysis of clinical data from the Atherosclerosis Risk in Communities Study demonstrated that serum sodium significantly contributes to prediction of plasma vWF and risk of stroke. The results indicate that elevation of extracellular sodium within the physiological range raises vWF sufficiently to increase coagulability and risk of thrombosis.
Assuntos
Células Endoteliais da Veia Umbilical Humana/metabolismo , Sódio/metabolismo , Trombofilia/complicações , Trombofilia/metabolismo , Trombose/complicações , Trombose/metabolismo , Fator de von Willebrand/metabolismo , Animais , Desidratação/sangue , Desidratação/complicações , Desidratação/metabolismo , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/patologia , Humanos , Camundongos , Pessoa de Meia-Idade , Osmose/efeitos dos fármacos , Fatores de Risco , Transdução de Sinais/efeitos dos fármacos , Sódio/sangue , Cloreto de Sódio/farmacologia , Acidente Vascular Cerebral/sangue , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/metabolismo , Trombofilia/sangue , Trombose/sangue , Fatores de Transcrição/metabolismoRESUMO
High concentration of NaCl increases DNA breaks both in cell culture and in vivo. The breaks remain elevated as long as NaCl concentration remains high and are rapidly repaired when the concentration is lowered. The exact nature of the breaks, and their location, has not been entirely clear, and it has not been evident how cells survive, replicate, and maintain genome integrity in environments like the renal inner medulla in which cells are constantly exposed to high NaCl concentration. Repair of the breaks after NaCl is reduced is accompanied by formation of foci containing phosphorylated H2AX (γH2AX), which occurs around DNA double-strand breaks and contributes to their repair. Here, we confirm by specific comet assay and pulsed-field electrophoresis that cells adapted to high NaCl have increased levels of double-strand breaks. Importantly, γH2AX foci that occur during repair of the breaks are nonrandomly distributed in the mouse genome. By chromatin immunoprecipitation using anti-γH2AX antibody, followed by massive parallel sequencing (ChIP-Seq), we find that during repair of double-strand breaks induced by high NaCl, γH2AX is predominantly localized to regions of the genome devoid of genes ("gene deserts"), indicating that the high NaCl-induced double-strand breaks are located there. Localization to gene deserts helps explain why the DNA breaks are less harmful than are the random breaks induced by genotoxic agents such as UV radiation, ionizing radiation, and oxidants. We propose that the universal presence of NaCl around animal cells has directly influenced the evolution of the structure of their genomes.
Assuntos
Quebras de DNA de Cadeia Dupla , DNA/efeitos dos fármacos , Cloreto de Sódio/química , Animais , Bleomicina/farmacologia , Ensaio Cometa/métodos , DNA/genética , Dano ao DNA , Fragmentação do DNA , Enzimas Reparadoras do DNA/química , Histonas/química , Rim/metabolismo , Camundongos , Modelos Genéticos , Oxidantes/química , Fosforilação , Radiação Ionizante , Raios UltravioletaRESUMO
Dehydration with aging is attributed to decreased urine concentrating ability and thirst. We further investigated by comparing urine concentration and water balance in 3, 18 and 27 month old mice, consuming equal amounts of water. During water restriction, 3 month old mice concentrate their urine sufficiently to maintain water balance (stable weight). 18 month old mice concentrate their urine as well, but still lose weight (negative water balance). 27 month old mice do not concentrate their urine as well and lose even more weight than the 18 month old mice, indicating a larger negative water balance. Negative water balance in older mice is accompanied by increased vasopressin excretion, providing further evidence of dehydration. All 3 groups maintain water balance while consuming only the water in gel food containing 56% water. However, both older groups excrete a smaller volume of urine of higher osmolality, indicating greater extra urinary water loss. Since their feces also contain less water, the excess water lost by the older mice apparently is through other routes, presumably insensible loss through the respiratory tract and skin. The greater insensible water loss occurs at an earlier age (18 months) than decreased urine concentrating ability (27 months). We propose that insensible water loss through skin and respiration increases with age, making a major contribution to aging related dehydration.
Assuntos
Envelhecimento/fisiologia , Desidratação/etiologia , Perda Insensível de Água/fisiologia , Animais , CamundongosRESUMO
Mre11 is a critical participant in upkeep of nuclear DNA, its repair, replication, meiosis, and maintenance of telomeres. The upkeep of mitochondrial DNA (mtDNA) is less well characterized, and whether Mre11 participates has been unknown. We previously found that high NaCl causes some of the Mre11 to leave the nucleus, but we did not then attempt to localize it within the cytoplasm. In the present studies, we find Mre11 in mitochondria isolated from primary renal cells and show that the amount of Mre11 in mitochondria increases with elevation of extracellular NaCl. We confirm the presence of Mre11 in the mitochondria of cells by confocal microscopy and show that some of the Mre11 colocalizes with mtDNA. Furthermore, crosslinking of Mre11 to DNA followed by Mre11 immunoprecipitation directly demonstrates that some Mre11 binds to mtDNA. Abundant Mre11 is also present in tissue sections from normal mouse kidneys, colocalized with mitochondria of proximal tubule and thick ascending limb cells. To explore whether distribution of Mre11 changes with cell differentiation, we used an experimental model of tubule formation by culturing primary kidney cells in Matrigel matrix. In nondifferentiated cells, Mre11 is mostly in the nucleus, but it becomes mostly cytoplasmic upon cell differentiation. We conclude that Mre11 is present in mitochondria where it binds to mtDNA and that the amount in mitochondria varies depending on cellular stress and differentiation. Our results suggest a role for Mre11 in the maintenance of genome integrity in mitochondria in addition to its previously known role in maintenance of nuclear DNA.
Assuntos
Enzimas Reparadoras do DNA/metabolismo , DNA Mitocondrial/metabolismo , Proteínas de Ligação a DNA/metabolismo , Rim/enzimologia , Mitocôndrias/enzimologia , Animais , Sítios de Ligação , Diferenciação Celular , Núcleo Celular/enzimologia , Células Cultivadas , Citoplasma/enzimologia , Imunofluorescência , Imunoprecipitação , Rim/citologia , Proteína Homóloga a MRE11 , Camundongos , Microscopia Confocal , Pressão Osmótica , Transporte Proteico , Cloreto de Sódio/metabolismo , Estresse FisiológicoRESUMO
BACKGROUND: Hypertonicity, such as induced by high NaCl, increases the activity of the transcription factor TonEBP/OREBP whose target genes increase osmoprotective organic osmolytes and heat shock proteins. METHODOLOGY: We used mass spectrometry to analyze proteins that coimmunoprecipitate with TonEBP/OREBP in order to identify ones that might contribute to its high NaCl-induced activation. PRINCIPAL FINDINGS: We identified 20 unique peptides from Mediator of DNA Damage Checkpoint 1 (MDC1) with high probability. The identification was confirmed by Western analysis. We used small interfering RNA knockdown of MDC1 to characterize its osmotic function. Knocking down MDC1 reduces high NaCl-induced increases in TonEBP/OREBP transcriptional and transactivating activity, but has no significant effect on its nuclear localization. We confirm six previously known phosphorylation sites in MDC1, but do not find evidence that high NaCl increases phosphorylation of MDC1. It is suggestive that MDC1 acts as a DNA damage response protein since hypertonicity reversibly increases DNA breaks, and other DNA damage response proteins, like ATM, also associate with TonEBP/OREBP and contribute to its activation by hypertonicity. CONCLUSIONS/SIGNIFICANCE: MDC1 associates with TonEBP/OREBP and contributes to high NaCl-induced increase of that factor's transcriptional activity.
Assuntos
Fatores de Transcrição NFATC/metabolismo , Proteínas Nucleares/metabolismo , Cloreto de Sódio/farmacologia , Transativadores/metabolismo , Transporte Ativo do Núcleo Celular/efeitos dos fármacos , Proteínas Adaptadoras de Transdução de Sinal , Sequência de Aminoácidos , Proteínas Mutadas de Ataxia Telangiectasia , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Citoplasma/efeitos dos fármacos , Citoplasma/metabolismo , Dano ao DNA , Proteínas de Ligação a DNA/metabolismo , Relação Dose-Resposta a Droga , Técnicas de Silenciamento de Genes , Humanos , Immunoblotting , Espectrometria de Massas , Dados de Sequência Molecular , Proteínas Nucleares/química , Proteínas Nucleares/deficiência , Proteínas Nucleares/genética , Proteínas Serina-Treonina Quinases/metabolismo , Solubilidade , Transativadores/química , Transativadores/deficiência , Transativadores/genética , Transcrição Gênica , Proteínas Supressoras de Tumor/metabolismoRESUMO
NaCl induces DNA breaks, thus leading to cellular senescence. Here we showed that Ku86 deficiency accelerated the high NaCl-induced cellular senescence. We find that 1) high NaCl induces rapid cellular senescence in Ku86 deficient(xrs5) cells, 2) Ku86 deficiency shortens lifespan of C. elegans in high NaCl, and 3) cellular senescence is greatly accelerated in renal inner medullas of Ku86 (-/-) mice. Further, although water balance is known to be compromised in old mice, this occurs at much earlier age in Ku86(-/-) mice. When subjected to mild water restriction, 3 month old Ku86(-/-), but not Ku86(+/+),mice rapidly become dehydrated as evidenced by decrease in body weight, increased production of antidiuretic hormone,increased urine osmolality and decreased urine volume. The deficiency in water balance does not occur in Ku86(+/+)mice until they are much older (14 months). We conclude that Ku86 deficiency accelerates high NaCl(-) induced cellular senescence,particularly in the renal medulla where NaCl normally is high.