RESUMEN
The kidney and brain play critical roles in the regulation of blood pressure. Neuropeptide FF (NPFF), originally isolated from the bovine brain, has been suggested to contribute to the pathogenesis of hypertension. However, the roles of NPFF and its receptors, NPFF-R1 and NPFF-R2, in the regulation of blood pressure, via the kidney, are not known. In this study, we found that the transcripts and proteins of NPFF and its receptors, NPFF-R1 and NPFF-R2, were expressed in mouse and human renal proximal tubules (RPTs). In mouse RPT cells (RPTCs), NPFF, but not RF-amide-related peptide-2 (RFRP-2), decreased the forskolin-stimulated cAMP production in a concentration- and time-dependent manner. Furthermore, dopamine D1-like receptors colocalized and co-immunoprecipitated with NPFF-R1 and NPFF-R2 in human RPTCs. The increase in cAMP production in human RPTCs caused by fenoldopam, a D1-like receptor agonist, was attenuated by NPFF, indicating an antagonistic interaction between NPFF and D1-like receptors. The renal subcapsular infusion of NPFF in C57BL/6 mice decreased renal sodium excretion and increased blood pressure. The NPFF-mediated increase in blood pressure was prevented by RF-9, an antagonist of NPFF receptors. Taken together, our findings suggest that autocrine NPFF and its receptors in the kidney regulate blood pressure, but the mechanisms remain to be determined.
Asunto(s)
Comunicación Autocrina , Presión Sanguínea , AMP Cíclico , Oligopéptidos , Transducción de Señal , Animales , Humanos , Ratones , AMP Cíclico/metabolismo , Oligopéptidos/farmacología , Oligopéptidos/metabolismo , Receptores de Neuropéptido/metabolismo , Túbulos Renales Proximales/metabolismo , Masculino , Riñón/metabolismo , Ratones Endogámicos C57BL , Receptores de Dopamina D1/metabolismoRESUMEN
The understanding of how biological membranes are organized and how they function has constantly been evolving over the past decades. Instead of just serving as a medium in which specific proteins are located, certain parts of the lipid bilayer contribute to platforms that assemble signaling complexes by providing a microenvironment that facilitates effective protein-protein interactions. G protein-coupled receptors (GPCRs) and relevant signaling molecules, including the heterotrimeric G proteins, key enzymes such as kinases and phosphatases, trafficking proteins, and secondary messengers, preferentially partition to these highly organized cell membrane microdomains, called lipid rafts. Lipid rafts are essential for the trafficking and signaling of GPCRs. The study of GPCR biology in the context of lipid rafts involves the localization of the GPCR of interest in lipid rafts, at the basal state and upon receptor agonism, and the evaluation of the biological functions of the GPCR in appropriate cell lines. The lack of standardized methodologies to study lipid rafts, in general, and of the workings of GPCRs in lipid rafts, in particular, and the inescapable drawbacks of current methods have hampered the complete understanding of the underlying molecular mechanisms. Newer methodologies that allow the study of GPCRs in their native form are needed. The use of complementary approaches that produce mutually supportive results appears to be the best way for drawing conclusions with regard to the distribution and activity of GPCRs in lipid rafts.
Asunto(s)
Detergentes/química , Proteínas de Unión al GTP Heterotriméricas/metabolismo , Immunoblotting/métodos , Microdominios de Membrana/química , Microscopía Confocal/métodos , Receptores Acoplados a Proteínas G/metabolismo , Línea Celular , Proteínas de Unión al GTP Heterotriméricas/aislamiento & purificación , Humanos , Microdominios de Membrana/metabolismo , Receptores Acoplados a Proteínas G/aislamiento & purificación , Transducción de SeñalRESUMEN
Gastrin, secreted by G-cells, and glucagon-like peptide-1 (GLP-1), secreted by L-cells, may participate in the regulation of sodium balance. We studied the effect of sodium in mice in vivo and mouse ileum and human L-cells, on GLP-1 secretion, and the role of NFAT5 and gastrin-releasing peptide receptor (GRPR) in this process. A high-sodium diet increases serum GLP-1 levels in mice. Increasing sodium concentration stimulates GLP-1 secretion from mouse ileum and L-cells. GRP enhances the high sodium-induced increase in GLP-1 secretion. High sodium increases cellular GLP-1 expression, while low and high sodium concentrations increase NFAT5 and GRPR expression. Silencing NFAT5 in L-cells abrogates the stimulatory effect of GRP on the high sodium-induced GLP-1 secretion and protein expression, and the sodium-induced increase in GRPR expression. GLP-1 and gastrin decrease the expression of Na+-K+/ATPase and increase the phosphorylation of sodium/hydrogen exchanger type 3 (NHE3) in human renal proximal tubule cells (hRPTCs). This study gives a new perspective on the mechanisms of GLP-1 secretion, especially that engendered by ingested sodium, and the ability of GLP-1, with gastrin, to decrease Na+-K+/ATPase expression and NHE3 function in hRPTCs. These results may contribute to the better utilization of current and future GLP-1-based drugs in the treatment of hypertension.
Asunto(s)
Gastrinas/genética , Péptido 1 Similar al Glucagón/genética , Receptor del Péptido 1 Similar al Glucagón/genética , Hipertensión/genética , Factores de Transcripción/genética , Animales , Células Secretoras de Gastrina/metabolismo , Regulación de la Expresión Génica/genética , Silenciador del Gen , Humanos , Hipertensión/tratamiento farmacológico , Hipertensión/patología , Túbulos Renales Proximales/metabolismo , Ratones , Fosforilación/efectos de los fármacos , Sodio/metabolismo , Sodio/farmacología , Intercambiador 3 de Sodio-Hidrógeno/genética , ATPasa Intercambiadora de Sodio-Potasio/genéticaRESUMEN
Significance: The kidney plays an important role in the long-term control of blood pressure. Oxidative stress is one of the fundamental mechanisms responsible for the development of hypertension. Dopamine, via five subtypes of receptors, plays an important role in the control of blood pressure by various mechanisms, including the inhibition of oxidative stress. Recent Advances: Dopamine receptors exert their regulatory function to decrease the oxidative stress in the kidney and ultimately maintain normal sodium balance and blood pressure homeostasis. An aberration of this regulation may be involved in the pathogenesis of hypertension. Critical Issues: Our present article reviews the important role of oxidative stress and intrarenal dopaminergic system in the regulation of blood pressure, summarizes the current knowledge on renal dopamine receptor-mediated antioxidation, including decreasing reactive oxygen species production, inhibiting pro-oxidant enzyme nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase, and stimulating antioxidative enzymes, and also discusses its underlying mechanisms, including the increased activity of G protein-coupled receptor kinase 4 (GRK4) and abnormal trafficking of renal dopamine receptors in hypertensive status. Future Directions: Identifying the mechanisms of renal dopamine receptors in the regulation of oxidative stress and their contribution to the pathogenesis of hypertension remains an important research focus. Increased understanding of the role of reciprocal regulation between renal dopamine receptors and oxidative stress in the regulation of blood pressure may give us novel insights into the pathogenesis of hypertension and provide a new treatment strategy for hypertension.
Asunto(s)
Quinasa 4 del Receptor Acoplado a Proteína-G/genética , Hipertensión/genética , Riñón/metabolismo , Receptores Dopaminérgicos/genética , Antioxidantes/metabolismo , Presión Sanguínea/genética , Dopamina/genética , Dopamina/metabolismo , Hipertensión/metabolismo , Hipertensión/patología , Riñón/patología , NADPH Oxidasas/genética , Estrés Oxidativo/genética , Fosforilación/genética , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Numerous G protein-coupled receptors (GPCRs) and GPCR-signaling molecules reside in lipid rafts and thus, are inherently regulated in these microdomains. However, the limitations of current methods to investigate lipid raft biology and GPCR activity in situ have hindered the complete understanding of the molecular underpinnings of GPCR trafficking and signaling, especially in the whole organism. This book chapter details an innovative in vivo approach to study the crucial role of lipid rafts on the workings of GPCRs in the mouse kidney. This protocol involves the use of a modified mini osmotic pump to deliver an agent that selectively disrupts the lipid raft in the kidney.
Asunto(s)
Riñón/metabolismo , Lípidos de la Membrana/metabolismo , Microdominios de Membrana/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Animales , Ratones , Transporte de Proteínas/fisiología , Transducción de Señal/fisiologíaRESUMEN
Effective receptor signaling is anchored on the preferential localization of the receptor in lipid rafts, which are plasma membrane platforms replete with cholesterol and sphingolipids. We hypothesized that the dopamine D1 receptor (D1 R) contains structural features that allow it to reside in lipid rafts for its activity. Mutation of C347 palmitoylation site and Y218 of a newly identified Cholesterol Recognition Amino Acid Consensus motif resulted in the exclusion of D1 R from lipid rafts, blunted cAMP response, impaired sodium transport, and increased oxidative stress in renal proximal tubule cells (RPTCs). Kidney-restricted silencing of Drd1 in C57BL/6J mice increased blood pressure (BP) that was normalized by renal tubule-restricted rescue with D1 R-wild-type but not the mutant D1 R 347A that lacks a palmitoylation site. Kidney-restricted disruption of lipid rafts by ß-MCD jettisoned the D1 R from the brush border, decreased sodium excretion, and increased oxidative stress and BP in C57BL/6J mice. Deletion of the PX domain of the novel D1 R-binding partner sorting nexin 19 (SNX19) resulted in D1 R partitioning solely to non-raft domains, while silencing of SNX19 impaired D1 R function in RPTCs. Kidney-restricted silencing of Snx19 resulted in hypertension in C57BL/6J mice. Our results highlight the essential role of lipid rafts for effective D1 R signaling.
Asunto(s)
Riñón/metabolismo , Microdominios de Membrana/metabolismo , Receptores de Dopamina D1/metabolismo , Animales , Sitios de Unión/genética , Presión Sanguínea/genética , Presión Sanguínea/fisiología , Células Cultivadas , AMP Cíclico/metabolismo , Silenciador del Gen , Humanos , Túbulos Renales Proximales/metabolismo , Lipoilación , Masculino , Ratones , Ratones Endogámicos C57BL , Mutagénesis Sitio-Dirigida , Estrés Oxidativo , Receptores de Dopamina D1/deficiencia , Receptores de Dopamina D1/genética , Sodio/metabolismoRESUMEN
Acute renal depletion of sorting nexin 1 (SNX1) in mice results in blunted natriuretic response and hypertension due to impaired dopamine D5 receptor (D5 R) activity. We elucidated the molecular mechanisms for these phenotypes in Snx1-/- mice. These mice had increased renal expressions of angiotensin II type 1 receptor (AT1 R), NADPH oxidase (NOX) subunits, D5 R, and NaCl cotransporter. Basal reactive oxygen species (ROS), NOX activity, and blood pressure (BP) were also higher in Snx1-/- mice, which were normalized by apocynin, a drug that prevents NOX assembly. Renal proximal tubule (RPT) cells from hypertensive (HT) Euro-American males had deficient SNX1 activity, impaired D5 R endocytosis, and increased ROS compared with cells from normotensive (NT) Euro-American males. siRNA-mediated depletion of SNX1 in RPT cells from NT subjects led to a blunting of D5 R agonist-induced increase in cAMP production and decrease in Na+ transport, effects that were normalized by over-expression of SNX1. Among HT African-Americans, three of the 12 single nucleotide polymorphisms interrogated for the SNX1 gene were associated with a decrease in systolic BP in response to hydrochlorothiazide (HCTZ). The results illustrate a new paradigm for the development of hypertension and imply that the trafficking protein SNX1 may be a crucial determinant for hypertension and response to antihypertensive therapy.
Asunto(s)
Hipertensión/metabolismo , Estrés Oxidativo/fisiología , Nexinas de Clasificación/metabolismo , Animales , Presión Sanguínea/fisiología , Línea Celular , Femenino , Humanos , Riñón/metabolismo , Túbulos Renales Proximales/metabolismo , Masculino , Ratones , NADPH Oxidasas/metabolismo , Oxidación-Reducción , Transporte de Proteínas/fisiología , ARN Interferente Pequeño/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Receptor de Angiotensina Tipo 1/metabolismoRESUMEN
The sorting nexin (SNX) family consists of a diverse group of cytoplasmic- and membrane-associated phosphoinositide-binding proteins that play pivotal roles in the regulation of protein trafficking. This includes the entire endocytic pathway, such as endocytosis, endosomal sorting, and endosomal signaling. Dysfunctions of SNX pathway are involved in several forms of cardiovascular disease (CVD). Moreover, SNX gene variants are associated with CVDs. In this review, we discuss the current knowledge on SNX-mediated regulatory mechanisms and their roles in the pathogenesis and treatment of CVDs.
Asunto(s)
Enfermedades Cardiovasculares/metabolismo , Sistema Cardiovascular/metabolismo , Nexinas de Clasificación/metabolismo , Animales , Enfermedades Cardiovasculares/genética , Enfermedades Cardiovasculares/fisiopatología , Enfermedades Cardiovasculares/terapia , Sistema Cardiovascular/fisiopatología , Endocitosis , Endosomas/metabolismo , Humanos , Pronóstico , Transporte de Proteínas , Transducción de Señal , Nexinas de Clasificación/genéticaRESUMEN
Hypertension is the most prevalent cause of cardiovascular disease and kidney failure, but only about 50% of patients achieve adequate blood pressure control, in part, due to inter-individual genetic variations in the response to antihypertensive medication. Significant strides have been made toward the understanding of the role of reactive oxygen species (ROS) in the regulation of the cardiovascular system. However, the role of ROS in human hypertension is still unclear. Polymorphisms of some genes involved in the regulation of ROS production are associated with hypertension, suggesting their potential influence on blood pressure control and response to antihypertensive medication. This review provides an update on the genes associated with the regulation of ROS production in hypertension and discusses the controversies on the use of antioxidants in the treatment of hypertension, including the antioxidant effects of antihypertensive drugs.
Asunto(s)
Presión Sanguínea/genética , Polimorfismo Genético/genética , Especies Reactivas de Oxígeno/metabolismo , Animales , Antioxidantes/metabolismo , Humanos , Hipertensión/genética , Hipertensión/metabolismoRESUMEN
BACKGROUND: Multiple interrelated pathways contribute to the pathogenesis of preeclampsia, and variants in susceptibility genes may play a role among Filipinos, an ethnically distinct group with high prevalence of the disease. The objective of this study was to examine the association between variants in maternal candidate genes and the development of preeclampsia in a Philippine population. METHODS: A case-control study involving 29 single nucleotide polymorphisms (SNPs) in 21 candidate genes was conducted in 150 patients with preeclampsia (cases) and 175 women with uncomplicated normal pregnancies (controls). Genotyping for the GRK4 and DRD1 gene variants was carried out using the TaqMan Assay, and all other variants were assayed using the Sequenom MassARRAY Iplex Platform. PLINK was used for SNP association testing. Multilocus association analysis was performed using multifactor dimensionality reduction (MDR) analysis. RESULTS: Among the clinical factors, older age (P < 1 × 10-4), higher BMI (P < 1 × 10-4), having a new partner (P = 0.006), and increased time interval from previous pregnancy (P = 0.018) associated with preeclampsia. The MDR algorithm identified the genetic variant ACVR2A rs1014064 as interacting with age and BMI in association with preeclampsia among Filipino women. CONCLUSIONS: The MDR algorithm identified an interaction between age, BMI and ACVR2A rs1014064, indicating that context among genetic variants and demographic/clinical factors may be crucial to understanding the pathogenesis of preeclampsia among Filipino women.
Asunto(s)
Receptores de Activinas Tipo II/genética , Polimorfismo de Nucleótido Simple , Preeclampsia/genética , Adulto , Factores de Edad , Índice de Masa Corporal , Estudios de Casos y Controles , Femenino , Predisposición Genética a la Enfermedad , Genotipo , Humanos , Reducción de Dimensionalidad Multifactorial , Filipinas , Preeclampsia/etnología , Embarazo , Adulto JovenRESUMEN
Leptin is a pro-inflammatory cytokine secreted by the adipose tissue. Dopamine D2 receptors (D2Rs) have anti-inflammatory effects in the brain and kidney tissues. Mouse and human adipocytes express D2R; D2R protein was 10-fold greater in adipocytes from human visceral tissue than subcutaneous tissue. However, the function of D2R in adipocytes is not well understood. 3T3-L1 cells were treated with D2-like receptor agonist quinpirole, and immunoblot and quantitative PCR were performed. Quinpirole increased the protein and mRNA expression of leptin and IL-6, but not adiponectin and visfatin (24 h). It also increased the mRNA expression of TNF-α , MCP1, and NFkB-p50. An acute increase in the protein expression of leptin and TNF-α was also found in the cells treated with quinpirole. The leptin concentration in the culture media was increased by quinpirole-bathing the 3T3-L1 adipocytes. These quinpirole effects on leptin and IL-6 expression were prevented by the D2R antagonist L741,626. Similarly, siRNA-mediated silencing of Drd2 decreased the leptin, IL-6, mRNA, and protein expressions. The D2R-mediated increase in leptin expression was prevented by the phosphoinositide 3-kinase inhibitor LY294002. Acute quinpirole treatment in C57Bl/6J mice increased serum leptin concentration and leptin mRNA in visceral adipocyte tissue but not in subcutaneous adipocytes, confirming the stimulatory effect of D2R on leptin in vivo. Our results suggest that the stimulation of D2R increases leptin production and may have a tissue-specific pro-inflammatory effect in adipocytes.
Asunto(s)
Adipocitos/metabolismo , Interleucina-6/metabolismo , Leptina/metabolismo , Receptores de Dopamina D2/metabolismo , Regulación hacia Arriba , Células 3T3-L1 , Animales , Células Cultivadas , Humanos , Masculino , Ratones , Ratones Endogámicos C57BLRESUMEN
AIMS/HYPOTHESIS: We hypothesised that renal sorting nexin 5 (SNX5) regulates the insulin-degrading enzyme (IDE) and, thus, circulating insulin levels. We therefore studied the dynamic interaction between SNX5 and IDE in human renal proximal tubule cells (hRPTCs), as well as in rat and mouse kidneys. METHODS: The regulation of IDE by SNX5 expressed in the kidney was studied in vitro and in vivo. Snx5 or mock siRNA was added to immortalised hRPTCs (passage <20) in culture or selectively infused, via osmotic mini-pump, into the remnant kidney of uninephrectomised mice and rats. RESULTS: SNX5 co-localised with IDE at the plasma membrane and perinuclear area of hRPTCs and in the brush border membrane of proximal tubules of human, rat, and mouse kidneys. Insulin increased the co-localisation and co-immunoprecipitation of SNX5 and IDE in hRPTCs. Silencing SNX5 in hRPTCs decreased IDE expression and activity. Renal-selective silencing of Snx5 (SNX5 protein: 100 ± 25 vs 29 ± 10, p < 0.05 [% of control]) in C57Bl/6J mice decreased IDE protein (100 ± 13 vs 57 ± 6, p < 0.05 [% of control]) and urinary insulin excretion, impaired the responses to insulin and glucose, and increased blood insulin and glucose levels. Spontaneously hypertensive rats (SHRs) had increased blood insulin and glucose levels and decreased renal SNX5 (100 ± 27 vs 29 ± 6, p < 0.05 [% of control]) and IDE (100 ± 5 vs 75 ± 4, p < 0.05 [% of control]) proteins, compared with normotensive Wistar-Kyoto (WKY) rats. Kidney Snx5-depleted WKY rats also had increased blood insulin and glucose levels. The expression of SNX5 and IDE was decreased in RPTCs from SHRs and hypertensive humans compared with cells from normotensive volunteers, indicating a common cause for hyperinsulinaemia and hypertension. CONCLUSIONS/INTERPRETATION: Renal SNX5 positively regulates IDE expression and function. This study is the first to demonstrate the novel and crucial role of renal SNX5 in insulin and glucose metabolism.
Asunto(s)
Insulisina/metabolismo , Nexinas de Clasificación/metabolismo , Animales , Western Blotting , Línea Celular , Humanos , Inmunoprecipitación , Técnicas In Vitro , Resistencia a la Insulina/genética , Insulisina/genética , Riñón/metabolismo , Masculino , Ratones , Ratones Mutantes , Microscopía Confocal , Microscopía Fluorescente , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/fisiología , Ratas , Ratas Endogámicas WKY , Reacción en Cadena en Tiempo Real de la Polimerasa , Nexinas de Clasificación/genéticaRESUMEN
The rising prevalence of primary pediatric hypertension and its tracking into adult hypertension point to the importance of determining its pathogenesis to gain insights into its current and emerging management. Considering that the intricate control of BP is governed by a myriad of anatomical, molecular biological, biochemical, and physiological systems, multiple genes are likely to influence an individual's BP and susceptibility to develop hypertension. The long-term regulation of BP rests on renal and non-renal mechanisms. One renal mechanism relates to sodium transport. The impaired renal sodium handling in primary hypertension and salt sensitivity may be caused by aberrant counter-regulatory natriuretic and anti-natriuretic pathways. The sympathetic nervous and renin-angiotensin-aldosterone systems are examples of antinatriuretic pathways. An important counter-regulatory natriuretic pathway is afforded by the renal autocrine/paracrine dopamine system, aberrations of which are involved in the pathogenesis of hypertension, including that associated with obesity. We present updates on the complex interactions of these two systems with dietary salt intake in relation to obesity, insulin resistance, inflammation, and oxidative stress. We review how insults during pregnancy such as maternal and paternal malnutrition, glucocorticoid exposure, infection, placental insufficiency, and treatments during the neonatal period have long-lasting effects in the regulation of renal function and BP. Moreover, these effects have sex differences. There is a need for early diagnosis, frequent monitoring, and timely management due to increasing evidence of premature target organ damage. Large controlled studies are needed to evaluate the long-term consequences of the treatment of elevated BP during childhood, especially to establish the validity of the current definition and treatment of pediatric hypertension.
Asunto(s)
Intervención Médica Temprana/métodos , Hipertensión , Resistencia a la Insulina/fisiología , Sistema Renina-Angiotensina/fisiología , Cloruro de Sodio Dietético/metabolismo , Niño , Humanos , Hipertensión/etiología , Hipertensión/metabolismo , Hipertensión/fisiopatología , Hipertensión/terapia , Obesidad/metabolismo , Obesidad/fisiopatología , Estrés Oxidativo/fisiologíaRESUMEN
We tested the hypothesis that salt-sensitive hypertension is caused by renal oxidative stress by measuring the blood pressure and reactive oxygen species-related proteins in the kidneys of human G protein-coupled receptor kinase 4γ (hGRK4γ) 486V transgenic mice and non-transgenic (Non-T) littermates on normal and high salt diets. High salt diet increased the blood pressure, associated with impaired sodium excretion, in hGRK4γ486V mice. Renal expressions of NOX isoforms were similar in both strains on normal salt diet but NOX2 was decreased by high salt diet to a greater extent in Non-T than hGRK4γ486V mice. Renal HO-2, but not HO-1, protein was greater in hGRK4γ486V than Non-T mice on normal salt diet and normalized by high salt diet. On normal salt diet, renal CuZnSOD and ECSOD proteins were similar but renal MnSOD was lower in hGRK4γ486V than Non-T mice and remained low on high salt diet. High salt diet decreased renal CuZnSOD in hGRK4γ486V but not Non-T mice and decreased renal ECSOD to a greater extent in hGRK4γ486V than Non-T mice. Renal SOD activity, superoxide production, and NOS3 protein were similar in two strains on normal salt diet. However, high salt diet decreased SOD activity and NOS3 protein and increased superoxide production in hGRK4γ486V mice but not in Non-T mice. High salt diet also increased urinary 8-isoprostane and 8-hydroxydeoxyguanosine to a greater extent in hGRK4γ486V than Non-T mice. hGRK4γwild-type mice were normotensive and hGRK4γ142V mice were hypertensive but both were salt-resistant and in normal redox balance. Chronic tempol treatment partially prevented the salt-sensitivity of hGRK4γ486V mice. Thus, hGRK4γ486V causes salt-sensitive hypertension due, in part, to defective renal antioxidant mechanisms.
Asunto(s)
Quinasa 4 del Receptor Acoplado a Proteína-G/genética , Hipertensión/enzimología , Óxido Nítrico Sintasa de Tipo III/genética , Superóxido Dismutasa/genética , Animales , Presión Sanguínea/genética , Modelos Animales de Enfermedad , Hemo-Oxigenasa 1/genética , Humanos , Hipertensión/metabolismo , Hipertensión/fisiopatología , Riñón/enzimología , Riñón/fisiopatología , Proteínas de la Membrana/genética , Ratones , Ratones Transgénicos , NADPH Oxidasa 2/genética , Estrés Oxidativo/genética , Tolerancia a la Sal/genética , Sales (Química)/toxicidad , Superóxidos/metabolismoRESUMEN
The vascular endothelial growth factor (VEGF) family is important for establishing normal pregnancy, and related single nucleotide polymorphisms (SNPs) are implicated in abnormal placentation and preeclampsia. We evaluated the association between preeclampsia and several VEGF SNPs among Filipinos, an ethnically distinct group with high prevalence of preeclampsia. The genotypes and allelic variants were determined in a case-control study (191 controls and 165 preeclampsia patients) through SNP analysis of VEGF-A (rs2010963, rs3025039) and VEGF-C (rs7664413) and their corresponding receptors VEGFR1 (rs722503, rs12584067, rs7335588) and VEGFR3 (rs307826) from venous blood DNA. VEGF-A rs3025039 C allele has been shown to associate with preeclampsia (odds ratio of 1.648 (1.03-2.62)), while the T allele bestowed an additive effect for the maintenance of normal, uncomplicated pregnancy and against the development of preeclampsia (odds ratio of 0.62 (0.39-0.98)). VEGFR1 rs722503 is associated with preeclampsia occurring at or after the age of 40 years. The results showed that genetic variability of VEGF-A and VEGFR1 are important in the etiology of preeclampsia among Filipinos.
Asunto(s)
Placentación/genética , Preeclampsia , Factor A de Crecimiento Endotelial Vascular/genética , Factor C de Crecimiento Endotelial Vascular/genética , Receptor 1 de Factores de Crecimiento Endotelial Vascular/genética , Receptor 3 de Factores de Crecimiento Endotelial Vascular/genética , Adulto , Alelos , Estudios de Casos y Controles , Femenino , Genotipo , Humanos , Oportunidad Relativa , Filipinas/etnología , Polimorfismo de Nucleótido Simple , Preeclampsia/epidemiología , Preeclampsia/genética , Embarazo , Factor A de Crecimiento Endotelial Vascular/sangreRESUMEN
The understanding of how biological membranes are organized and how they function has evolved. Instead of just serving as a medium in which certain proteins are found, portions of the lipid bilayer have been demonstrated to form specialized platforms that foster the assembly of signaling complexes by providing a microenvironment that is conducive for effective protein-protein interactions. G protein-coupled receptors (GPCRs) and relevant signaling molecules, including the heterotrimeric G proteins, key enzymes such as kinases and phosphatases, trafficking proteins, and secondary messengers, preferentially partition to these highly organized cell membrane microdomains, called lipid rafts. As such, lipid rafts are crucial for the trafficking and signaling of GPCRs. The study of GPCR biology in the context of lipid rafts involves the localization of the GPCR of interest in lipid rafts, at the basal state and upon receptor agonism, and the evaluation of the biological functions of the GPCR in appropriate cell lines. The lack of standardized methodology to study lipid rafts, in general, and of the workings of GPCRs in lipid rafts, in particular, and the inherent drawbacks of current methods have hampered the complete understanding of the underlying molecular mechanisms. Newer methodologies that allow the study of GPCRs in their native form are needed. The use of complementary approaches that produce mutually supportive results appear to be the best way for drawing conclusions with regards to the distribution and activity of GPCRs in lipid rafts.
Asunto(s)
Microdominios de Membrana/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Células Cultivadas , Humanos , Microscopía Fluorescente , Transporte de Proteínas , Receptores Acoplados a Proteínas G/aislamiento & purificación , Transducción de SeñalRESUMEN
The influence of a single gene on the pathogenesis of essential hypertension may be difficult to ascertain, unless the gene interacts with other genes that are germane to blood pressure regulation. G-protein-coupled receptor kinase type 4 (GRK4) is one such gene. We have reported that the expression of its variant hGRK4γ(142V) in mice results in hypertension because of impaired dopamine D1 receptor. Signaling through dopamine D1 receptor and angiotensin II type I receptor (AT1R) reciprocally modulates renal sodium excretion and blood pressure. Here, we demonstrate the ability of the hGRK4γ(142V) to increase the expression and activity of the AT1R. We show that hGRK4γ(142V) phosphorylates histone deacetylase type 1 and promotes its nuclear export to the cytoplasm, resulting in increased AT1R expression and greater pressor response to angiotensin II. AT1R blockade and the deletion of the Agtr1a gene normalize the hypertension in hGRK4γ(142V) mice. These findings illustrate the unique role of GRK4 by targeting receptors with opposite physiological activity for the same goal of maintaining blood pressure homeostasis, and thus making the GRK4 a relevant therapeutic target to control blood pressure.
Asunto(s)
Bencimidazoles/farmacología , Presión Sanguínea/fisiología , Quinasa 4 del Receptor Acoplado a Proteína-G/genética , Regulación de la Expresión Génica , Histona Desacetilasa 1/antagonistas & inhibidores , Hipertensión/genética , Receptor de Angiotensina Tipo 1/genética , Tetrazoles/farmacología , Bloqueadores del Receptor Tipo 1 de Angiotensina II/farmacología , Animales , Compuestos de Bifenilo , Modelos Animales de Enfermedad , Hipertensión Esencial , Femenino , Quinasa 4 del Receptor Acoplado a Proteína-G/biosíntesis , Células HEK293 , Histona Desacetilasa 1/metabolismo , Humanos , Hipertensión/tratamiento farmacológico , Hipertensión/metabolismo , Immunoblotting , Riñón/metabolismo , Riñón/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , ARN/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Receptor de Angiotensina Tipo 1/biosíntesis , Receptor de Angiotensina Tipo 1/efectos de los fármacos , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
Salt sensitivity is estimated to be present in 51% of the hypertensive and 26% of the normotensive populations. The individual blood pressure response to salt is heterogeneous and possibly related to inherited susceptibility. Although the mechanisms underlying salt sensitivity are complex and not well understood, genetics can help to determine the blood response to salt intake. So far only a few genes have been found to be associated with salt-sensitive hypertension using candidate gene association studies. The kidney is critical to overall fluid and electrolyte balance and long-term regulation of blood pressure. Thus, the pathogenesis of salt sensitivity must involve a derangement in renal NaCl handling: an inability to decrease renal sodium transport and increase sodium excretion in the face of an increase in NaCl load that could be caused by aberrant counter-regulatory natriuretic/antinatriuretic pathways. We review here the literature regarding the gene variants associated with salt-sensitive hypertension and how the presence of these gene variants influences the response to antihypertensive therapy.
Asunto(s)
Presión Sanguínea/efectos de los fármacos , Estudios de Asociación Genética , Hipertensión/genética , Riñón/fisiopatología , Sodio en la Dieta/farmacología , Regulación de la Expresión Génica/fisiología , Variación Genética , Humanos , Polimorfismo Genético , Especies Reactivas de Oxígeno/metabolismo , Sistema Renina-Angiotensina/efectos de los fármacos , Sistema Renina-Angiotensina/fisiologíaRESUMEN
Renal dopamine 2 receptor dysfunction is associated with oxidative stress and high blood pressure (BP). We have reported that DJ-1, an oxidative stress response protein, is positively regulated by dopamine 2 receptor in the kidney. The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) regulates the expression of several antioxidant genes. We tested the hypothesis that Nrf2 is involved in the renal DJ-1-mediated inhibition of reactive oxygen species production. We have reported that silencing dopamine 2 receptor in mouse renal proximal tubule cells decreases the expression of DJ-1. We now report that silencing DJ-1 or dopamine 2 receptor in mouse proximal tubule cells and mouse kidneys decreases Nrf2 expression and activity and increases reactive oxygen species production; BP is also increased in mice in which renal DJ-1 or dopamine 2 receptor is silenced. DJ-1(-/-) mice have decreased renal Nrf2 expression and activity and increased nitro-tyrosine levels and BP. Silencing Nrf2 in mouse proximal tubule cells does not alter the expression of DJ-1 or dopamine 2 receptor, indicating that Nrf2 is downstream of dopamine 2 receptor and DJ-1. An Nrf2 inducer, bardoxolone, normalizes the systolic BP and renal malondialdehyde levels in DJ-1(-/-) mice without affecting them in their wild-type littermates. Because Nrf2 ubiquitination is increased in DJ-1(-/-) mice, we conclude that the protective effect of DJ-1 on renal oxidative stress is mediated, in part, by preventing Nrf2 degradation. Moreover, renal dopamine 2 receptor and DJ-1 are necessary for normal Nrf2 activity to keep a normal redox balance and BP.