RESUMEN

Climate change driven Sea Level Rise (SLR) is creating a major global environmental crisis in coastal ecosystems, however, limited practical solutions are provided to prevent or mitigate the impacts. Here, we propose a novel eco-engineering solution to protect highly valued vegetated intertidal ecosystems. The new 'Tidal Replicate Method' involves the creation of a synthetic tidal regime that mimics the desired hydroperiod for intertidal wetlands. This synthetic tidal regime can then be applied via automated tidal control systems, "SmartGates", at suitable locations. As a proof of concept study, this method was applied at an intertidal wetland with the aim of restabilising saltmarsh vegetation at a location representative of SLR. Results from aerial drone surveys and on-ground vegetation sampling indicated that the Tidal Replicate Method effectively established saltmarsh onsite over a 3-year period of post-restoration, showing the method is able to protect endangered intertidal ecosystems from submersion. If applied globally, this method can protect high value coastal wetlands with similar environmental settings, including over 1,184,000 ha of Ramsar coastal wetlands. This equates to a saving of US$230 billion in ecosystem services per year. This solution can play an important role in the global effort to conserve coastal wetlands under accelerating SLR.

RESUMEN

Cardiotonic steroids (CTSs) are NKA α-1 (Na+/K+-ATPase α-1) ligands that are increased in volume expanded states and associated with cardiac and renal diseases. Although initiation and resolution of inflammation is an important component of cellular injury and repair in renal disease, it is unknown whether CTS activation of NKA α-1 signaling in this setting regulates this inflammatory response. On this background, we hypothesized that CTS signaling through the NKA α-1-Src kinase complex promotes a proinflammatory response in renal epithelial and immune cells. First, we observed that the CTS telocinobufagin activated multiple proinflammatory cytokines/chemokines in renal epithelial cells, and these effects were attenuated after either NKA α-1 knockdown or with a specific inhibitor of the NKA α-1-Src kinase complex (pNaKtide). Similar findings were observed in immune cells, where we demonstrated that while telocinobufagin induced both oxidative burst and enhanced Nuclear factor kappa-light-chain-enhancer of activated B cells activation in macrophages ( P<0.05), the effects were abolished in NKA α-1+/- macrophages or by pretreatment with pNaKtide or the Src inhibitor PP2 ( P<0.01). In a series of in vivo studies, we found that 5/6th partial nephrectomy induced significantly less oxidative stress in the remnant kidney of NKA α-1+/- versus wild-type mice. Similarly, 5/6th partial nephrectomy yielded decreased levels of the urinary oxidative stress marker 8-Oxo-2'-deoxyguanosine in NKA α-1+/- versus wild-type mice. Finally, we found that in vivo inhibition of the NKA α-1-Src kinase complex with pNaKtide significantly inhibited renal proinflammatory gene expression after 5/6th partial nephrectomy. These findings suggest that the NKA α-1-Src kinase complex plays a central role in regulating the renal inflammatory response induced by elevated CTS both in vitro and in vivo.

Asunto(s)

Bufanólidos/farmacología , Glicósidos Cardíacos/farmacología , Insuficiencia Renal Crónica/patología , Transducción de Señal , ATPasa Intercambiadora de Sodio-Potasio/genética , Animales , Biopsia con Aguja , Células Cultivadas , Quimiocinas/metabolismo , Células Epiteliales/citología , Células Epiteliales/efectos de los fármacos , Inmunohistoquímica , Inflamación/patología , Riñón/citología , Macrófagos/citología , Macrófagos/efectos de los fármacos , Ratones , Insuficiencia Renal Crónica/tratamiento farmacológico , Sensibilidad y Especificidad

RESUMEN

Pre-clinical studies investigated the effects of chronic exposure to nicotine on lungs, kidneys and brains using animal models. Most of these studies delivered nicotine into the circulatory and central nervous systems (CNS) through intraperitoneal injection or oral consumption methods. Few studies used inhalation machine system for nicotine delivery into brains in rodents to mimic human exposure to cigarettes. However, finding a more accurate and clinically relevant method of nicotine delivery is critical. A computerized inhalation machine has been designed (SciReq) and is currently employed in several institutions. The computerized machine delivers electronic (e)-cigarette vapor as well as tobacco smoke to rodents using marketed e-cigarette devices or tobacco cigarettes. This provides evidence about clinical effects of nicotine delivery by traditional methods (combustible cigarettes) and new methodologies (e-cigarettes) in physiological systems. Potential neurobiological mechanisms for the development of nicotine dependence have been determined recently in mice exposed to e-cigarette vapors in our laboratory using SciReq system. In this review article, the discussion focuses on the efficiency and practical applicability of using this computerized inhalation exposure system in inducing significant changes in brain protein expression and function as compared to other nicotine delivery methods. The SciReq inhalation system utilized in our laboratory and others is a method of nicotine delivery to the CNS, which has physiological relevance and mimics human inhalant exposures. Translation of the effects of inhaled nicotine on the CNS into clinical settings could provide important health considerations.

RESUMEN

Non-coding RNAs are important regulators of protein-coding genes. The current study characterized an antisense long non-coding RNA, ATP1A1-AS1, which is located on the opposite strand of the Na/K-ATPase α1 gene. Our results show that four splice variants are expressed in human adult kidney cells (HK2 cells) and embryonic kidney cells (HEK293 cells). These variants can be detected in both cytosol and nuclear fractions. We also found that the inhibition of DNA methylation has a differential effect on the expression of ATP1A1-AS1 and its sense gene. To investigate the physiological role of this antisense gene, we overexpressed the ATP1A1-AS1 transcripts, and examined their effect on Na/K-ATPase expression and related signaling function in human kidney cells. The results showed that overexpression of the ATP1A1-AS1-203 transcript in HK2 cells reduced the Na/K-ATPase α1 (ATP1A1) gene expression by approximately 20% (p < 0.05), while reducing the Na/K-ATPase α1 protein synthesis by approximately 22% (p < 0.05). Importantly, overexpression of the antisense RNA transcript attenuated ouabain-induced Src activation in HK2 cells. It also inhibited the cell proliferation and potentiated ouabain-induced cell death. These results demonstrate that the ATP1A1-AS1 gene is a moderate negative regulator of Na/K-ATPase α1, and can modulate Na/K-ATPase-related signaling pathways in human kidney cells.

Asunto(s)

Riñón/metabolismo , ARN sin Sentido/metabolismo , ARN Largo no Codificante/metabolismo , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Western Blotting , Línea Celular , Proliferación Celular/genética , Proliferación Celular/fisiología , Epigénesis Genética/genética , Epigénesis Genética/fisiología , Células HEK293 , Factor Nuclear 3-alfa del Hepatocito/genética , Factor Nuclear 3-alfa del Hepatocito/metabolismo , Humanos , ARN sin Sentido/genética , ARN Largo no Codificante/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción de Señal/genética , Transducción de Señal/fisiología , ATPasa Intercambiadora de Sodio-Potasio/genética

RESUMEN

The Na/K-ATPase is an important membrane ion transporter and a signaling receptor that is essential for maintaining normal cell function. The current study examined the role of Na/K-ATPase signaling in regulating miR-29b-3p, an anti-fibrotic microRNA, in a mouse chronic kidney disease (CKD) model (5/6th partial nephrectomy or PNx). The results showed that CKD induced significant reduction of miR-29b-3p expression in the heart tissue by activation of Src and NFκB signaling in these animals. To demonstrate the role of Na/K-ATPase signaling, we also performed the PNx surgery on Na/K-ATPase α1 heterozygous (α1+/-) mice, which expresses ~40% less Na/K-ATPase α1 compared to their wild type littermates (WT) and exhibits deficiency in Na/K-ATPase signaling. We found that CKD did not significantly change the miR-29b-3p expression in heart tissue from the α1+/- animals. We also found that CKD failed to activate Src and NFκB signaling in these animals. Using isolated cardiac fibroblasts from α1+/- mice and their WT littermates, we showed that ouabain, a specific Na/K-ATPase ligand, induces decreased miR-29b-3p expression in fibroblasts isolated from WT mice, but had no effect in cells from α1+/- mice. Inhibition of NFκB by Bay11-7082 prevented ouabain-induced miR-29b-3p reduction in WT fibroblasts. To further confirm the in vivo effect of Na/K-ATPase signaling in regulation of miR-29b-3p and cardiac fibrosis in CKD animals, we used pNaKtide, a Src inhibiting peptide derived from the sequence of Na/K-ATPase, to block the activation of Na/K-ATPase signaling. The result showed that pNaKtide injection significantly increased miR-29b-3p expression and mitigated the CKD-induced cardiac fibrosis in these animals. These results clearly demonstrated that Na/K-ATPase signaling is an important mediator in CKD that regulates miR-29b-3p expression and cardiac fibrosis, which provides a novel target for regulation of miR-29b-3p in CKD. We also demonstrate that antagonizing Na/K-ATPase signaling by pNaKtide can reduce organ fibrosis through the stimulation of tissue miR-29b-3p expression.

Asunto(s)

MicroARNs/genética , Miocardio/patología , Insuficiencia Renal Crónica/genética , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Animales , Células Cultivadas , Modelos Animales de Enfermedad , Regulación hacia Abajo , Fibrosis , Humanos , Masculino , Ratones , Miocardio/metabolismo , Nitrilos/farmacología , Ouabaína/farmacología , Insuficiencia Renal Crónica/metabolismo , Transducción de Señal , ATPasa Intercambiadora de Sodio-Potasio/genética , Sulfonas/farmacología

RESUMEN

Electronic (e)-cigarettes theoretically may be safer than conventional tobacco. However, our prior studies demonstrated direct adverse effects of e-cigarette vapor (EV) on airway cells, including decreased viability and function. We hypothesize that repetitive, chronic inhalation of EV will diminish airway barrier function, leading to inflammatory protein release into circulation, creating a systemic inflammatory state, ultimately leading to distant organ injury and dysfunction. C57BL/6 and CD-1 mice underwent nose only EV exposure daily for 3-6 mo, followed by cardiorenal physiological testing. Primary human bronchial epithelial cells were grown at an air-liquid interface and exposed to EV for 15 min daily for 3-5 days before functional testing. Daily inhalation of EV increased circulating proinflammatory and profibrotic proteins in both C57BL/6 and CD-1 mice: the greatest increases observed were in angiopoietin-1 (31-fold) and EGF (25-fold). Proinflammatory responses were recapitulated by daily EV exposures in vitro of human airway epithelium, with EV epithelium secreting higher IL-8 in response to infection (227 vs. 37 pg/ml, respectively; P < 0.05). Chronic EV inhalation in vivo reduced renal filtration by 20% ( P = 0.017). Fibrosis, assessed by Masson's trichrome and Picrosirius red staining, was increased in EV kidneys (1.86-fold, C57BL/6; 3.2-fold, CD-1; P < 0.05), heart (2.75-fold, C57BL/6 mice; P < 0.05), and liver (1.77-fold in CD-1; P < 0.0001). Gene expression changes demonstrated profibrotic pathway activation. EV inhalation altered cardiovascular function, with decreased heart rate ( P < 0.01), and elevated blood pressure ( P = 0.016). These data demonstrate that chronic inhalation of EV may lead to increased inflammation, organ damage, and cardiorenal and hepatic disease.

Asunto(s)

Barrera Alveolocapilar/efectos de los fármacos , Sistemas Electrónicos de Liberación de Nicotina , Inflamación/inducido químicamente , Nicotina/administración & dosificación , Nicotina/efectos adversos , Agonistas Nicotínicos/administración & dosificación , Agonistas Nicotínicos/efectos adversos , Animales , Citocinas/sangre , Femenino , Fibrosis/inducido químicamente , Expresión Génica/efectos de los fármacos , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos ICR , Cultivo Primario de Células , Mucosa Respiratoria/citología , Mucosa Respiratoria/efectos de los fármacos , Sistema Respiratorio/efectos de los fármacos

RESUMEN

This corrects the article DOI: 10.1038/srep34592.

RESUMEN

Liquid biopsies have advanced rapidly in recent years for use in diagnostic and prognostic applications. One important aspect of this advancement is the growth in our understanding of microRNA (miRNA) biology. The measurement of miRNAs packaged within exosomes, which are constantly released into the blood stream, may reflect pathological changes within the body. The current study performed miRNA profiling using plasma and plasma-derived exosome samples from two animal models of kidney disease, the 5/6th partial nephrectomy (PNx) and two-kidney-one-clip (2K1C) models. The RT-qPCR-based profiling results revealed that the overall miRNA expression level was much higher in plasma than in plasma-derived exosomes. With 200µl of either plasma or exosomes derived from the same volume of plasma, 629 out of 665 total miRNAs analyzed were detectable in plasma samples from sham-operated rats, while only 403 were detectable in exosomes with a cutoff value set at 35cycles. Moreover, the average miRNA expression level in plasma was about 16-fold higher than that in exosomes. We also found a select subset of miRNAs that were enriched within exosomes. The number of detectable miRNAs from plasma-derived exosomes was increased in rats subjected to PNx or 2K1C surgery compared to sham-operated animals. Importantly, we found that the changes of individual miRNAs measured in plasma had very poor concordance with that measured in plasma-derived exosomes in both animal models, suggesting that miRNAs in plasma and plasma-derived exosomes are differentially regulated in these disease conditions. Interestingly, PNx and 2K1C surgeries induced similar changes in miRNA expression, implying that common pathways were activated in these two disease models. Pathway analyses using DIANA-miRPath v3.0 showed that significantly changed exosomal miRNAs were associated with extracellular matrix (ECM) receptor interaction and mucin type-O-glycan synthesis pathways, which are related with tissue fibrosis and kidney injury, respectively. In conclusion, our results demonstrated that due to the differential changes in miRNAs, the measurement of exosomal miRNAs cannot be replaced by the measurement of miRNAs in plasma, or vice versa. We also showed that a set of miRNAs related with kidney injury and organ fibrosis were dysregulated in plasma-derived exosomes from animal models of kidney disease.

Asunto(s)

Exosomas/química , Enfermedades Renales/genética , MicroARNs/análisis , Animales , Modelos Animales de Enfermedad , Enfermedades Renales/sangre , Masculino , MicroARNs/sangre , Nefrectomía , Ratas , Ratas Sprague-Dawley

RESUMEN

Alteration in glutamate neurotransmission has been found to mediate the development of drug dependence, including nicotine. We and others, through using western blotting, have reported that exposure to drugs of abuse reduced the expression of glutamate transporter-1 (GLT-1) as well as cystine/glutamate antiporter (xCT), which consequently increased extracellular glutamate concentrations in the mesocorticolimbic area. However, our previous studies did not reveal any changes in glutamate/aspartate transporter (GLAST) following exposure to drugs of abuse. In the present study, for the first time, we investigated the effect of chronic exposure to electronic (e)-cigarette vapor containing nicotine, for one hour daily for six months, on GLT-1, xCT, and GLAST expression in frontal cortex (FC), striatum (STR), and hippocampus (HIP) in outbred female CD1 mice. In this study, we also investigated the expression of alpha-7 nicotinic acetylcholine receptor (α-7 nAChR), a major pre-synaptic nicotinic receptor in the glutamatergic neurons, which regulates glutamate release. We found that inhalation of e-cigarette vapor for six months increased α-7 nAChR expression in both FC and STR, but not in the HIP. In addition, chronic e-cigarette exposure reduced GLT-1 expression only in STR. Moreover, e-cigarette vapor inhalation induced downregulation of xCT in both the STR and HIP. We did not find any significant changes in GLAST expression in any brain region. Finally, using liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques, we detected high concentrations of nicotine and cotinine, a major metabolite of nicotine, in the FC tissues of e-cigarette exposed mice. These data provide novel evidence about the effects of chronic nicotine inhalation on the expression of key glial glutamate transporters as well as α-7 nAChR. Our work may suggest that nicotine exposure via chronic inhalation of e-cigarette vapor may be mediated in part by alterations in the glutamatergic system.

Asunto(s)

Sistema de Transporte de Aminoácidos X-AG/biosíntesis , Sistema de Transporte de Aminoácidos y+/biosíntesis , Sistemas Electrónicos de Liberación de Nicotina , Neuroglía/efectos de los fármacos , Neuroglía/metabolismo , Nicotina/administración & dosificación , Nicotina/farmacología , Receptor Nicotínico de Acetilcolina alfa 7/biosíntesis , Administración por Inhalación , Animales , Cuerpo Estriado/metabolismo , Transportador 2 de Aminoácidos Excitadores/biosíntesis , Femenino , Lóbulo Frontal/metabolismo , Hipocampo/metabolismo , Ratones , Neuronas/metabolismo , Nicotina/metabolismo

RESUMEN

Cigarette smoking causes cardiovascular disease and is associated with poor kidney function in individuals with diabetes mellitus and primary kidney diseases. However, the association of smoking on patients with atherosclerotic renal artery stenosis has not been studied. The current study utilized data from the Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL, NCT00081731) clinical trial to evaluate the effects of smoking on the risk of cardio-renal events and kidney function in this population. Baseline data showed that smokers (n = 277 out of 931) were significantly younger at enrollment than non-smokers (63.3±9.1 years vs 72.4±7.8 years; p<0.001). In addition, patients who smoke were also more likely to have bilateral renal artery stenoses and peripheral vascular disease (PVD). Longitudinal analysis showed that smokers experienced composite endpoint events (defined as first occurrence of: stroke; cardiovascular or renal death; myocardial infarction; hospitalization for congestive heart failure; permanent renal replacement; and progressive renal insufficiency defined as 30% reduction of GFR from baseline sustained for ≥ 60 days) at a substantially younger age compared to non-smokers (67.1±9.0 versus 76.1±7.9, p<0.001). Using linear regression and generalized linear modeling analysis controlled by age, sex, and ethnicity, smokers had significantly higher cystatin C levels (1.3±0.7 vs 1.2±0.9, p<0.01) whereas creatinine and estimated glomerular filtration rate (eGFR) were not different from non-smokers. From these data we conclude that smoking has a significant association with deleterious cardio-renal outcomes in patients with renovascular hypertension.

Asunto(s)

Aterosclerosis/complicaciones , Enfermedades Cardiovasculares/complicaciones , Nicotiana , Obstrucción de la Arteria Renal/complicaciones , Fumar , Anciano , Anciano de 80 o más Años , Aterosclerosis/fisiopatología , Enfermedades Cardiovasculares/fisiopatología , Estudios de Casos y Controles , Femenino , Tasa de Filtración Glomerular , Humanos , Masculino , Obstrucción de la Arteria Renal/fisiopatología

RESUMEN

INTRODUCTION: Clinically, patients with significant reductions in renal function present with cardiovascular dysfunction typically termed, uremic cardiomyopathy. It is a progressive series of cardiac pathophysiological changes, including left ventricular diastolic dysfunction and hypertrophy (LVH) which sometimes progress to left ventricular dilation (LVD) and systolic dysfunction in the setting of chronic kidney disease (CKD). Uremic cardiomyopathy is almost ubiquitous in patients afflicted with end stage renal disease (ESRD). Areas covered: This article reviews recent epidemiology, pathophysiology of uremic cardiomyopathy and provide a board overview of Na/K-ATPase research with detailed discussion on the mechanisms of Na/K-ATPase/Src/ROS amplification loop. We also present clinical and preclinical evidences as well as molecular mechanism of this amplification loop in the development of uremic cardiomyopathy. A potential therapeutic peptide that targets on this loop is discussed. Expert opinion: Current clinical treatment for uremic cardiomyopathy remains disappointing. Targeting the ROS amplification loop mediated by the Na/K-ATPase signaling function may provide a novel therapeutic target for uremic cardiomyopathy and related diseases. Additional studies of Na/K-ATPase and other strategies that regulate this loop will lead to new therapeutics.

Asunto(s)

Cardiomiopatías/tratamiento farmacológico , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Uremia/complicaciones , Animales , Cardiomegalia/etiología , Cardiomegalia/fisiopatología , Cardiomiopatías/etiología , Cardiomiopatías/fisiopatología , Humanos , Fallo Renal Crónico/complicaciones , Terapia Molecular Dirigida , Péptidos/farmacología , Especies Reactivas de Oxígeno/metabolismo , Disfunción Ventricular Izquierda/etiología , Disfunción Ventricular Izquierda/fisiopatología

RESUMEN

High blood pressure is a common cause of chronic kidney disease. Because CD40, a member of the tumor necrosis factor receptor family, has been linked to the progression of kidney disease in ischemic nephropathy, we studied the role of Cd40 in the development of hypertensive renal disease. The Cd40 gene was mutated in the Dahl S genetically hypertensive rat with renal disease by targeted-gene disruption using zinc-finger nuclease technology. These rats were then given low (0.3%) and high (2%) salt diets and compared. The resultant Cd40 mutants had significantly reduced levels of both urinary protein excretion (41.8 ± 3.1 mg/24 h vs. 103.7 ± 4.3 mg/24 h) and plasma creatinine (0.36 ± 0.05 mg/dl vs. 1.15 ± 0.19 mg/dl), with significantly higher creatinine clearance compared with the control S rats (3.04 ± 0.48 ml/min vs. 0.93 ± 0.15 ml/min), indicating renoprotection was conferred by mutation of the Cd40 locus. Furthermore, the Cd40 mutants had a significant attenuation in renal fibrosis, which persisted on the high salt diet. However, there was no difference in systolic blood pressure between the control and Cd40 mutant rats. Thus, these data serve as the first evidence for a direct link between Cd40 and hypertensive nephropathy. Hence, renal fibrosis is one of the underlying mechanisms by which Cd40 plays a crucial role in the development of hypertensive renal disease.

Asunto(s)

Presión Sanguínea/genética , Antígenos CD40/genética , Hipertensión/genética , Enfermedades Renales/prevención & control , Riñón/metabolismo , Mutación , Proteinuria/prevención & control , Animales , Linfocitos B/metabolismo , Antígenos CD40/metabolismo , Movimiento Celular , Creatinina/sangre , Dieta Hiposódica , Modelos Animales de Enfermedad , Fibrosis , Predisposición Genética a la Enfermedad , Hipertensión/metabolismo , Hipertensión/fisiopatología , Riñón/patología , Riñón/fisiopatología , Enfermedades Renales/genética , Enfermedades Renales/metabolismo , Enfermedades Renales/fisiopatología , Activación de Linfocitos , Fenotipo , Fosforilación , Inhibidor 1 de Activador Plasminogénico/metabolismo , Proteinuria/genética , Proteinuria/metabolismo , Proteinuria/fisiopatología , Ratas Endogámicas Dahl , Ratas Mutantes , Eliminación Renal , Cloruro de Sodio Dietético , Linfocitos T/metabolismo , Factores de Tiempo , Familia-src Quinasas/metabolismo

RESUMEN

We have previously reported that the sodium potassium adenosine triphosphatase (Na/K-ATPase) can effect the amplification of reactive oxygen species. In this study, we examined whether attenuation of oxidant stress by antagonism of Na/K-ATPase oxidant amplification might ameliorate experimental uremic cardiomyopathy induced by partial nephrectomy (PNx). PNx induced the development of cardiac morphological and biochemical changes consistent with human uremic cardiomyopathy. Both inhibition of Na/K-ATPase oxidant amplification with pNaKtide and induction of heme oxygenase-1 (HO-1) with cobalt protoporphyrin (CoPP) markedly attenuated the development of phenotypical features of uremic cardiomyopathy. In a reversal study, administration of pNaKtide after the induction of uremic cardiomyopathy reversed many of the phenotypical features. Attenuation of Na/K-ATPase oxidant amplification may be a potential strategy for clinical therapy of this disorder.

Asunto(s)

Cardiomiopatías/terapia , Inhibidores Enzimáticos/administración & dosificación , Oxidantes/metabolismo , ATPasa Intercambiadora de Sodio-Potasio/antagonistas & inhibidores , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Uremia/complicaciones , Animales , Modelos Animales de Enfermedad , Activadores de Enzimas/administración & dosificación , Hemo-Oxigenasa 1/metabolismo , Masculino , Ratones Endogámicos C57BL , Protoporfirinas/administración & dosificación , Especies Reactivas de Oxígeno/metabolismo , Resultado del Tratamiento

RESUMEN

BACKGROUND: Experimental uremic cardiomyopathy causes cardiac fibrosis and is causally related to the increased circulating levels of the cardiotonic steroid, marinobufagenin (MBG), which signals through Na/K-ATPase. Rapamycin is an inhibitor of the serine/threonine kinase mammalian target of rapamycin (mTOR) implicated in the progression of many different forms of renal disease. Given that Na/K-ATPase signaling is known to stimulate the mTOR system, we speculated that the ameliorative effects of rapamycin might influence this pathway. METHODS AND RESULTS: Biosynthesis of MBG by cultured human JEG-3 cells is initiated by CYP27A1, which is also a target for rapamycin. It was demonstrated that 1 µmol/L of rapamycin inhibited production of MBG in human JEG-2 cells. Male Sprague-Dawley rats were subjected to either partial nephrectomy (PNx), infusion of MBG, and/or infusion of rapamycin through osmotic minipumps. PNx animals showed marked increase in plasma MBG levels (1025±60 vs 377±53 pmol/L; P<0.01), systolic blood pressure (169±1 vs 111±1 mm Hg; P<0.01), and cardiac fibrosis compared to controls. Plasma MBG levels were significantly decreased in PNx-rapamycin animals compared to PNx (373±46 vs 1025±60 pmol/L; P<0.01), and cardiac fibrosis was substantially attenuated by rapamycin treatment. CONCLUSIONS: Rapamycin treatment in combination with MBG infusion significantly attenuated cardiac fibrosis. Our results suggest that rapamycin may have a dual effect on cardiac fibrosis through (1) mTOR inhibition and (2) inhibiting MBG-mediated profibrotic signaling and provide support for beneficial effect of a novel therapy for uremic cardiomyopathy.

Asunto(s)

Presión Sanguínea/efectos de los fármacos , Bufanólidos/farmacología , Cardiomiopatías/patología , Inhibidores Enzimáticos/farmacología , Fibroblastos/efectos de los fármacos , Corazón/efectos de los fármacos , Inmunosupresores/farmacología , Miocardio/patología , Sirolimus/farmacología , Uremia/patología , Animales , Bufanólidos/metabolismo , Cardiomiopatías/metabolismo , Células Cultivadas , Fibroblastos/metabolismo , Fibroblastos/patología , Fibrosis , Humanos , Masculino , Nefrectomía , Ratas , Ratas Sprague-Dawley , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Uremia/metabolismo

RESUMEN

Clinical studies indicate that smoking combustible cigarettes promotes progression of renal and cardiac injury, leading to functional decline in the setting of chronic kidney disease (CKD). However, basic studies using in vivo small animal models that mimic clinical pathology of CKD are lacking. To address this issue, we evaluated renal and cardiac injury progression and functional changes induced by 4 wk of daily combustible cigarette smoke exposure in the 5/6th partial nephrectomy (PNx) CKD model. Molecular evaluations revealed that cigarette smoke significantly (P < 0.05) decreased renal and cardiac expression of the antifibrotic microRNA miR-29b-3 and increased expression of molecular fibrosis markers. In terms of cardiac and renal organ structure and function, exposure to cigarette smoke led to significantly increased systolic blood pressure, cardiac hypertrophy, cardiac and renal fibrosis, and decreased renal function. These data indicate that decreased expression of miR-29b-3p is a novel mechanism wherein cigarette smoke promotes accelerated cardiac and renal tissue injury in CKD. (155 words).

Asunto(s)

Fumar Cigarrillos/genética , Epigénesis Genética/genética , Fibrosis/genética , Corazón/fisiopatología , Riñón/patología , Miocardio/patología , Animales , Biomarcadores/metabolismo , Presión Sanguínea/genética , Masculino , MicroARNs/genética , Ratas , Ratas Sprague-Dawley , Insuficiencia Renal Crónica/genética

RESUMEN

BACKGROUND: We have demonstrated that cardiotonic steroids, such as ouabain, signaling through the Na/K-ATPase, regulate sodium reabsorption in the renal proximal tubule. By direct carbonylation modification of the Pro222 residue in the actuator (A) domain of pig Na/K-ATPase α1 subunit, reactive oxygen species are required for ouabain-stimulated Na/K-ATPase/c-Src signaling and subsequent regulation of active transepithelial (22)Na(+) transport. In the present study we sought to determine the functional role of Pro222 carbonylation in Na/K-ATPase signaling and sodium handling. METHODS AND RESULTS: Stable pig α1 knockdown LLC-PK1-originated PY-17 cells were rescued by expressing wild-type rat α1 and rat α1 with a single mutation of Pro224 (corresponding to pig Pro222) to Ala. This mutation does not affect ouabain-induced inhibition of Na/K-ATPase activity, but abolishes the effects of ouabain on Na/K-ATPase/c-Src signaling, protein carbonylation, Na/K-ATPase endocytosis, and active transepithelial (22)Na(+) transport. CONCLUSIONS: Direct carbonylation modification of Pro224 in the rat α1 subunit determines ouabain-mediated Na/K-ATPase signal transduction and subsequent regulation of renal proximal tubule sodium transport.

Asunto(s)

Túbulos Renales Proximales/metabolismo , Carbonilación Proteica , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Sodio/metabolismo , Animales , Animales Modificados Genéticamente , Proteína Tirosina Quinasa CSK , Células Cultivadas , Técnicas de Silenciamiento del Gen , Túbulos Renales Proximales/citología , Mutación , Ouabaína/farmacología , Ratas , Transducción de Señal , ATPasa Intercambiadora de Sodio-Potasio/antagonistas & inhibidores , ATPasa Intercambiadora de Sodio-Potasio/genética , Porcinos , Familia-src Quinasas/metabolismo

RESUMEN

Missing responses are common problems in medical, social, and economic studies. When responses are missing at random, a complete case data analysis may result in biases. A popular debias method is inverse probability weighting proposed by Horvitz and Thompson. To improve efficiency, Robins et al. proposed an augmented inverse probability weighting method. The augmented inverse probability weighting estimator has a double-robustness property and achieves the semiparametric efficiency lower bound when the regression model and propensity score model are both correctly specified. In this paper, we introduce an empirical likelihood-based estimator as an alternative to Qin and Zhang (2007). Our proposed estimator is also doubly robust and locally efficient. Simulation results show that the proposed estimator has better performance when the propensity score is correctly modeled. Moreover, the proposed method can be applied in the estimation of average treatment effect in observational causal inferences. Finally, we apply our method to an observational study of smoking, using data from the Cardiovascular Outcomes in Renal Atherosclerotic Lesions clinical trial. Copyright © 2016 John Wiley & Sons, Ltd.

Asunto(s)

Interpretación Estadística de Datos , Funciones de Verosimilitud , Simulación por Computador , Humanos , Modelos Estadísticos , Puntaje de Propensión

RESUMEN

Cardiac progenitor cells including c-kit(+) cells and cardiosphere-derived cells (CDCs) play important roles in cardiac repair and regeneration. CDCs were reported to contain only small subpopulations of c-kit(+) cells and recent publications suggested that depletion of the c-kit(+) subpopulation of cells has no effect on regenerative properties of CDCs. However, our current study showed that the vast majority of CDCs from murine heart actually express c-kit, albeit, in an intracellular and non-glycosylated form. Immunostaining and flow cytometry showed that the fluorescent signal indicative of c-kit immunostaining significantly increased when cell membranes were permeabilized. Western blots further demonstrated that glycosylation of c-kit was increased during endothelial differentiation in a time dependent manner. Glycosylation inhibition by 1-deoxymannojirimycin hydrochloride (1-DMM) blocked c-kit glycosylation and reduced expression of endothelial cell markers such as Flk-1 and CD31 during differentiation. Pretreatment of these cells with a c-kit kinase inhibitor (imatinib mesylate) also attenuated Flk-1 and CD31 expression. These results suggest that c-kit glycosylation and its kinase activity are likely needed for these cells to differentiate into an endothelial lineage. In vivo, we found that intracellular c-kit expressing cells are located in the wall of cardiac blood vessels in mice subjected to myocardial infarction. In summary, our work demonstrated for the first time that c-kit is not only expressed in CDCs but may also directly participate in CDC differentiation into an endothelial lineage.

Asunto(s)

Miocardio/citología , Proteínas Proto-Oncogénicas c-kit/metabolismo , Células Madre/metabolismo , Animales , Diferenciación Celular/efectos de los fármacos , Linaje de la Célula , Células Cultivadas , Glicosilación , Mesilato de Imatinib/farmacología , Inmunohistoquímica , Ratones , Ratones Endogámicos C57BL , Infarto del Miocardio/metabolismo , Infarto del Miocardio/patología , Molécula-1 de Adhesión Celular Endotelial de Plaqueta/metabolismo , Proteínas Proto-Oncogénicas c-kit/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Células Madre/citología , Células Madre/efectos de los fármacos , Receptor 2 de Factores de Crecimiento Endotelial Vascular/metabolismo

RESUMEN

Chronic kidney disease (CKD) is accompanied by cardiac fibrosis, hypertrophy, and dysfunction, which are commonly referred to as uremic cardiomyopathy. Our previous studies found that Na/K-ATPase ligands or 5/6th partial nephrectomy (PNx) induces cardiac fibrosis in rats and mice. The current study used in vitro and in vivo models to explore novel roles for microRNA in this mechanism of cardiac fibrosis formation. To accomplish this, we performed microRNA profiling with RT-qPCR based arrays on cardiac tissue from rats subjected to marinobufagenin (MBG) infusion or PNx. The analysis showed that a series of fibrosis-related microRNAs were dysregulated. Among the dysregulated microRNAs, microRNA (miR)-29b-3p, which directly targets mRNA of collagen, was consistently reduced in both PNx and MBG-infused animals. In vitro experiments demonstrated that treatment of primary cultures of adult rat cardiac fibroblasts with Na/K-ATPase ligands induced significant increases in the fibrosis marker, collagen protein, and mRNA expression compared with controls, whereas miR-29b-3p expression decreased >50%. Transfection of miR-29b-3p mimics into cardiac fibroblasts inhibited cardiotonic steroids-induced collagen synthesis. Moreover, a specific Na/K-ATPase signaling antagonist, pNaKtide, prevented ouabain-induced increases in collagen synthesis and decreases in miR-29b-3p expression in these cells. In conclusion, these data are the first to indicate that signaling through Na/K-ATPase regulates miRNAs and specifically, miR-29b-3p expression both in vivo and in vitro. Additionally, these data indicate that miR-29b-3p expression plays an important role in the formation of cardiac fibrosis in CKD.

Asunto(s)

Colágeno/biosíntesis , Fibroblastos/metabolismo , MicroARNs/metabolismo , Transducción de Señal , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Animales , Bufanólidos , Cardiotónicos/farmacología , Células Cultivadas , Regulación hacia Abajo/genética , Fibroblastos/efectos de los fármacos , Fibrosis , Perfilación de la Expresión Génica , Ventrículos Cardíacos/efectos de los fármacos , Ventrículos Cardíacos/metabolismo , Masculino , MicroARNs/genética , Miocardio/metabolismo , Miocardio/patología , Nefrectomía , Ouabaína/farmacología , Ratas Sprague-Dawley , Transducción de Señal/efectos de los fármacos , Esteroides/farmacología , Transfección

RESUMEN

The diagnosis of renal artery stenosis (RAS) has become increasingly common in part due to greater awareness of ischemic renal disease and increased use of diagnostic techniques. Over 90 % of RAS cases are caused by atherosclerotic renovascular disease (ARVD). Patients with ARVD are at high risk for fatal and nonfatal cardiovascular and renal events. The mortality rate in patients with ARVD is high, especially with other cardiovascular or renal comorbidities. Recent clinical studies have provided substantial evidence concerning medical therapy and endovascular interventional therapeutic approaches for ARVD. Despite previous randomized clinical trials, the optimal therapy for ARVD remained uncertain until the results of the Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) trial were released recently. CORAL demonstrated that optimal medical therapy was equally effective to endovascular therapy in the treatment of ARVD. Clinicians can now practice with more evidence-based medicine to treat ARVD and potentially decrease mortality in patients with ARVD using optimal medical therapy.

Asunto(s)

Angioplastia de Balón/métodos , Inhibidores de la Enzima Convertidora de Angiotensina/uso terapéutico , Aterosclerosis/patología , Obstrucción de la Arteria Renal/terapia , Anciano , Antihipertensivos/uso terapéutico , Procedimientos Endovasculares/métodos , Medicina Basada en la Evidencia , Femenino , Humanos , Hipertensión Renal/mortalidad , Hipertensión Renal/patología , Hipertensión Renal/terapia , Masculino , Persona de Mediana Edad , Pronóstico , Ensayos Clínicos Controlados Aleatorios como Asunto , Obstrucción de la Arteria Renal/mortalidad , Obstrucción de la Arteria Renal/patología , Medición de Riesgo , Índice de Severidad de la Enfermedad , Stents , Tasa de Supervivencia , Resultado del Tratamiento