RESUMEN
Activation of nucleotide-binding oligomerization domain-like receptor pyrin domain containing 3 (NLRP3) inflammasome has been reported in diabetic complications including diabetic kidney disease (DKD). However, it remains unknown if NLRP3 inhibition is renoprotective in a clinically relevant interventional approach with established DKD. We therefore examined the effect of the NLRP3-specific inhibitor MCC950 in streptozotocin-induced diabetic mice to measure the impact of NLRP3 inhibition on renal inflammation and associated pathology in DKD. We identified an adverse effect of MCC950 on renal pathology in diabetic animals. Indeed, MCC950-treated diabetic animals showed increased renal inflammation and macrophage infiltration in association with enhanced oxidative stress as well as increased mesangial expansion and glomerulosclerosis when compared with vehicle-treated diabetic animals. Inhibition of the inflammasome by MCC950 in diabetic mice led to renal up-regulation of markers of inflammation (Il1ß, Il18 and Mcp1), fibrosis (Col1, Col4, Fn1, α-SMA, Ctgf and Tgfß1) and oxidative stress (Nox2, Nox4 and nitrotyrosine). In addition, enhanced glomerular accumulation of pro-inflammatory CD68 positive cells and pro-oxidant factor nitrotyrosine was identified in the MCC950-treated diabetic compared with vehicle-treated diabetic animals. Collectively, in this interventional model of established DKD, NLRP3 inhibition with MCC950 did not show renoprotective effects in diabetic mice. On the contrary, diabetic mice treated with MCC950 exhibited adverse renal effects particularly enhanced renal inflammation and injury including mesangial expansion and glomerulosclerosis.
Asunto(s)
Nefropatías Diabéticas/patología , Furanos/farmacología , Indenos/farmacología , Inflamasomas/efectos de los fármacos , Proteína con Dominio Pirina 3 de la Familia NLR/efectos de los fármacos , Sulfonamidas/farmacología , Animales , Diabetes Mellitus Experimental , Fibrosis , Furanos/efectos adversos , Indenos/efectos adversos , Inflamación/tratamiento farmacológico , Masculino , Ratones Noqueados para ApoE , Estrés Oxidativo/efectos de los fármacos , Sulfonamidas/efectos adversosRESUMEN
AIMS/HYPOTHESIS: We determined whether empagliflozin altered renal sympathetic nerve activity (RSNA) and baroreflexes in a diabetes model in conscious rabbits. METHODS: Diabetes was induced by alloxan, and RSNA, mean arterial pressure (MAP) and heart rate were measured before and after 1 week of treatment with empagliflozin, insulin, the diuretic acetazolamide or the ACE inhibitor perindopril, or no treatment, in conscious rabbits. RESULTS: Four weeks after alloxan administration, blood glucose was threefold and MAP 9% higher than non-diabetic controls (p < 0.05). One week of treatment with empagliflozin produced a stable fall in blood glucose (-43%) and increased water intake (+49%) but did not change RSNA, MAP or heart rate compared with untreated diabetic rabbits. The maximum RSNA to hypotension was augmented by 75% (p < 0.01) in diabetic rabbits but the heart rate baroreflex was unaltered. Empagliflozin and acetazolamide reduced the augmentation of the RSNA baroreflex (p < 0.05) to be similar to the non-diabetic group. Noradrenaline (norepinephrine) spillover was similar in untreated diabetic and non-diabetic rabbits but twofold greater in empagliflozin- and acetazolamide-treated rabbits (p < 0.05). CONCLUSIONS/INTERPRETATION: As empagliflozin can restore diabetes-induced augmented sympathetic reflexes, this may be beneficial in diabetic patients. A similar action of the diuretic acetazolamide suggests that the mechanism may involve increased sodium and water excretion. Graphical abstract.
Asunto(s)
Compuestos de Bencidrilo/uso terapéutico , Glucósidos/uso terapéutico , Animales , Barorreflejo/efectos de los fármacos , Glucemia/efectos de los fármacos , Presión Sanguínea/efectos de los fármacos , Peso Corporal/efectos de los fármacos , Frecuencia Cardíaca/efectos de los fármacos , Masculino , Perindopril/farmacología , Conejos , Inhibidores del Cotransportador de Sodio-Glucosa 2/farmacología , Sistema Nervioso Simpático/efectos de los fármacos , Sistema Nervioso Simpático/metabolismoRESUMEN
Chronic kidney disease (CKD) is associated with greater sympathetic nerve activity but it is unclear if this is a kidney-specific response or due to generalized stimulation of sympathetic nervous system activity. To determine this, we used a rabbit model of CKD in which quantitative comparisons with control rabbits could be made of kidney sympathetic nerve activity and whole-body norepinephrine spillover. Rabbits either had surgery to lesion 5/6th of the cortex of one kidney by electro-lesioning and two weeks later removal of the contralateral kidney, or sham lesioning and sham nephrectomy. After three weeks, the blood pressure was statistically significantly 20% higher in conscious rabbits with CKD compared to rabbits with a sham operation, but their heart rate was similar. Strikingly, kidney nerve activity was 37% greater than in controls, with greater burst height and frequency. Total norepinephrine spillover was statistically significantly lower by 34%, and kidney baroreflex curves were shifted to the right in rabbits with CKD. Plasma creatinine and urine output were elevated by 38% and 131%, respectively, and the glomerular filtration rate was 37% lower than in sham-operated animals (all statistically significant). Kidney gene expression of fibronectin, transforming growth factor-ß, monocyte chemotactic protein1, Nox4 and Nox5 was two- to eight-fold greater in rabbits with CKD than in control rabbits. Overall, the glomerular layer lesioning model in conscious rabbits produced a moderate, stable degree of CKD characterized by elevated blood pressure and increased kidney sympathetic nerve activity. Thus, our findings, together with that of a reduction in total norepinephrine spillover, suggest that kidney denervation, rather than generalized sympatholytic treatments, may represent a preferable management for CKD associated hypertension.
Asunto(s)
Insuficiencia Renal Crónica , Animales , Barorreflejo , Presión Sanguínea , Frecuencia Cardíaca , Riñón , Conejos , Sistema Nervioso SimpáticoRESUMEN
AIMS/HYPOTHESIS: Excessive production of reactive oxygen species (ROS) plays a detrimental role in the progression of diabetic kidney disease (DKD). Renal oxidative stress activates proinflammatory cytokines, chemokines and profibrotic factors in DKD. Increased expression of the prooxidant enzyme NADPH oxidase (NOX) 5 in kidneys of diabetic individuals has been hypothesised to correlate with renal injury and progression of DKD. Since the gene encoding NOX5 is not expressed in the mouse genome, we examined the effect of inducible human NOX5 expression in renal cells, selectively in either endothelial cells or vascular smooth muscle cells (VSMCs)/mesangial cells in a model of insulin-deficient diabetes, the Akita mouse. METHODS: Renal structural injury, including glomerulosclerosis, mesangial expansion and extracellular matrix protein accumulation, as well as renal inflammation, ROS formation and albuminuria, were examined in the NOX5 transgenic Akita mouse model of DKD. RESULTS: Expression of NOX5 in either endothelial cells or VSMCs/mesangial cells in diabetic Akita mice was associated with increased renal inflammation (monocyte chemoattractant protein-1, NF-κB and toll-like receptor-4) and glomerulosclerosis, as well as upregulation of protein kinase C-α and increased expression of extracellular matrix genes (encoding collagen III, fibronectin and α-smooth muscle actin) and proteins (collagen IV), most likely mediated via enhanced renal ROS production. The effect of VSMC/mesangial cell-specific NOX5 expression resulted in more pronounced renal fibrosis in comparison with endothelial cell-specific NOX5 expression in diabetic mice. In addition, albuminuria was significantly increased in diabetic VEcad+NOX5+ mice (1192 ± 194 µg/24 h) when compared with diabetic VEcad+NOX5- mice (770 ± 98 µg/24 h). Furthermore, the regulatory components of NOX5 activation, including heat shock protein 90 and transient receptor potential cation channel subfamily C member 6, were upregulated only in the presence of both NOX5 and diabetes. CONCLUSIONS/INTERPRETATION: The findings from this study highlight the importance of NOX5 in promoting diabetes-related renal injury and provide the rationale for the development of a selective NOX5 inhibitor for the prevention and/or treatment of DKD.
Asunto(s)
Albuminuria/metabolismo , Fibrosis/metabolismo , Inflamación/metabolismo , Riñón/metabolismo , Albuminuria/patología , Animales , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patología , Nefropatías Diabéticas/metabolismo , Modelos Animales de Enfermedad , Fibrosis/patología , Humanos , Inflamación/patología , Riñón/patología , Ratones , Ratones Transgénicos , Músculo Liso Vascular/metabolismo , NADPH Oxidasa 5/metabolismo , Estrés Oxidativo/fisiología , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Chronic renal and vascular oxidative stress in association with an enhanced inflammatory burden are determinant processes in the development and progression of diabetic complications including cardiovascular disease (CVD), atherosclerosis and diabetic kidney disease (DKD). Persistent hyperglycaemia in diabetes mellitus increases the production of reactive oxygen species (ROS) and activates mediators of inflammation as well as suppresses antioxidant defence mechanisms ultimately contributing to oxidative stress which leads to vascular and renal injury in diabetes. Furthermore, there is increasing evidence that ROS, inflammation and fibrosis promote each other and are part of a vicious connection leading to development and progression of CVD and kidney disease in diabetes.
Asunto(s)
Enfermedades Cardiovasculares/fisiopatología , Angiopatías Diabéticas/fisiopatología , Nefropatías Diabéticas/fisiopatología , Inflamación/fisiopatología , Estrés Oxidativo/fisiología , Animales , Enfermedades Cardiovasculares/metabolismo , Angiopatías Diabéticas/metabolismo , Nefropatías Diabéticas/metabolismo , Humanos , Inflamación/metabolismo , Ratones , Modelos Biológicos , Especies Reactivas de Oxígeno/metabolismoRESUMEN
AIMS/HYPOTHESIS: Oxidative stress is a promising target in diabetes-associated vasculopathies, with inhibitors of NADPH oxidases (NOX), in particular isoforms 1 and 4, shown to be safe in early clinical development. We have explored a highly relevant late-stage intervention protocol using the clinically most advanced compound, the NOX1/4 inhibitor GKT137831, to determine whether end-organ damage can be reversed/attenuated when GKT137831 is administered in the setting of established diabetic complications. METHODS: GKT137831 was administered at two doses, 30 mg kg-1 day-1 and 60 mg kg-1 day-1, to ApoE -/- mice 10 weeks after diabetes induction with streptozotocin (STZ), for a period of 10 weeks. RESULTS: Consistent with Nox4 -/- mouse data, GKT137831 was protective in a model of diabetic nephropathy at both the 30 mg kg-1 day-1 and 60 mg kg-1 day-1 doses, through suppression of proinflammatory and profibrotic processes. Conversely, in diabetic atherosclerosis, where Nox1 -/y and Nox4 -/- mice have yielded qualitatively opposing results, the net effect of pharmacological NOX1/4 inhibition was protection, albeit to a lower extent and only at the lower 30 mg kg-1 day-1 dose. CONCLUSIONS/INTERPRETATION: As dose-dependent and tissue-specific effects of the dual NOX1/4 inhibitor GKT137831 were observed, it is critical to define in further studies the relative balance of inhibiting NOX4 vs NOX1 in the micro- and macrovasculature in diabetes.
Asunto(s)
Complicaciones de la Diabetes/metabolismo , Complicaciones de la Diabetes/prevención & control , Diabetes Mellitus Experimental/tratamiento farmacológico , Diabetes Mellitus Experimental/metabolismo , NADH NADPH Oxidorreductasas/metabolismo , NADPH Oxidasas/metabolismo , Pirazoles/uso terapéutico , Piridinas/uso terapéutico , Animales , Aterosclerosis/metabolismo , Aterosclerosis/prevención & control , Diabetes Mellitus Experimental/genética , Nefropatías Diabéticas/metabolismo , Nefropatías Diabéticas/prevención & control , Ratones , Ratones Noqueados , NADH NADPH Oxidorreductasas/antagonistas & inhibidores , NADH NADPH Oxidorreductasas/deficiencia , NADH NADPH Oxidorreductasas/genética , NADPH Oxidasa 1 , NADPH Oxidasa 4 , NADPH Oxidasas/antagonistas & inhibidores , NADPH Oxidasas/deficiencia , NADPH Oxidasas/genética , Estrés Oxidativo/efectos de los fármacos , Pirazolonas , PiridonasRESUMEN
Oxidative stress is a consequence of up-regulation of pro-oxidant enzyme-induced reactive oxygen species (ROS) production and concomitant depletion of antioxidants. Elevated levels of ROS act as an intermediate and are the common denominator for various diseases including diabetes-associated macro-/micro-vascular complications and hypertension. A range of enzymes are capable of generating ROS, but the pro-oxidant enzyme family, nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOXs), are the only enzymes known to be solely dedicated to ROS generation in the vascular tissues, kidney, aortas and eyes. While there is convincing evidence for a role of NOX1 in vascular and eye disease and for NOX4 in renal injury, the role of NOX5 in disease is less clear. Although NOX5 is highly up-regulated in humans in disease, it is absent in rodents. Thus, so far it has not been possible to study NOX5 in traditional mouse or rat models of disease. In the present review, we summarize and critically analyse the emerging evidence for a pathophysiological role of NOX5 in disease including the expression, regulation and molecular and cellular mechanisms which have been demonstrated to be involved in NOX5 activation.
Asunto(s)
Proteínas de la Membrana/metabolismo , NADPH Oxidasas/metabolismo , Enfermedades Vasculares/enzimología , Animales , Endotelio Vascular/enzimología , Humanos , Proteínas de la Membrana/genética , Ratones , NADPH Oxidasa 5 , NADPH Oxidasas/genética , Ratas , Especies Reactivas de Oxígeno/metabolismo , Enfermedades Vasculares/genéticaRESUMEN
AIMS/HYPOTHESIS: Changes in podocyte morphology and function are associated with albuminuria and progression of diabetic nephropathy. NADPH oxidase 4 (NOX4) is the main source of reactive oxygen species (ROS) in the kidney and Nox4 is upregulated in podocytes in response to high glucose. We assessed the role of NOX4-derived ROS in podocytes in vivo in a model of diabetic nephropathy using a podocyte-specific NOX4-deficient mouse, with a major focus on the development of albuminuria and ultra-glomerular structural damage. METHODS: Streptozotocin-induced diabetes-associated changes in renal structure and function were studied in male floxedNox4 and podocyte-specific, NOX4 knockout (podNox4KO) mice. We assessed albuminuria, glomerular extracellular matrix accumulation and glomerulosclerosis, and markers of ROS and inflammation, as well as glomerular basement membrane thickness, effacement of podocytes and expression of the podocyte-specific protein nephrin. RESULTS: Podocyte-specific Nox4 deletion in streptozotocin-induced diabetic mice attenuated albuminuria in association with reduced vascular endothelial growth factor (VEGF) expression and prevention of the diabetes-induced reduction in nephrin expression. In addition, podocyte-specific Nox4 deletion reduced glomerular accumulation of collagen IV and fibronectin, glomerulosclerosis and mesangial expansion, as well as glomerular basement membrane thickness. Furthermore, diabetes-induced increases in renal ROS, glomerular monocyte chemoattractant protein-1 (MCP-1) and protein kinase C alpha (PKC-α) were attenuated in podocyte-specific NOX4-deficient mice. CONCLUSIONS/INTERPRETATION: Collectively, this study shows the deleterious effect of Nox4 expression in podocytes by promoting podocytopathy in association with albuminuria and extracellular matrix accumulation in experimental diabetes, emphasising the role of NOX4 as a target for new renoprotective agents.
Asunto(s)
Citoprotección/genética , Diabetes Mellitus Experimental/complicaciones , Nefropatías Diabéticas/genética , NADPH Oxidasas/genética , Podocitos/metabolismo , Albuminuria/genética , Albuminuria/patología , Animales , Diabetes Mellitus Experimental/inducido químicamente , Diabetes Mellitus Experimental/genética , Nefropatías Diabéticas/patología , Eliminación de Gen , Riñón/metabolismo , Riñón/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , NADPH Oxidasa 4 , NADPH Oxidasas/metabolismo , Especificidad de Órganos/genética , Podocitos/patología , EstreptozocinaRESUMEN
The cytokine transforming growth factor (TGF)-ß1 plays a central role in diabetic nephropathy (DN) with data implicating the miRNA (miR) miR-21 as a key modulator of its prosclerotic actions. In the present study, we demonstrate data indicating that miR-21 up-regulation positively correlates with the severity of fibrosis and rate of decline in renal function in human DN. Furthermore, concomitant analyses of various models of fibrotic renal disease and experimental DN, confirm tubular miR-21 up-regulation. The fibrotic changes associated with increased miR-21 levels are proposed to include the regulation of TGF-ß1-mediated mothers against decapentaplegic homolog 3 (SMAD3)- and phosphoinositide 3-kinase (PI3K)-dependent signalling pathways via co-ordinated repression of mothers against decapentaplegic homolog 7 (SMAD7) and phosphatase and tensin homologue (PTEN) respectively. This represents a previously uncharacterized interaction axis between miR-21 and PTEN-SMAD7. Targeting of these proteins by miR-21 resulted in de-repression of the respective pathways as reflected by increases in SMAD3 and V-Akt murine thymoma viral oncogene homolog 1 (AKT) phosphorylation. Many of the changes typically induced by TGF-ß1, including phosphorylation of signalling mediators, were further enhanced by miR-21. Collectively, these data present a unified model for a key role for miR-21 in the regulation of renal tubular extracellular matrix (ECM) synthesis and accumulation and provide important insights into the molecular pathways implicated in the progression of DN.
Asunto(s)
Nefropatías Diabéticas/metabolismo , Túbulos Renales Proximales/metabolismo , MicroARNs/metabolismo , Fosfohidrolasa PTEN/metabolismo , Proteína smad7/metabolismo , Animales , Apolipoproteínas E/deficiencia , Apolipoproteínas E/genética , Estudios de Casos y Controles , Línea Celular , Colágeno/metabolismo , Diabetes Mellitus Experimental/inducido químicamente , Diabetes Mellitus Experimental/complicaciones , Nefropatías Diabéticas/etiología , Nefropatías Diabéticas/genética , Nefropatías Diabéticas/patología , Fibrosis , Tasa de Filtración Glomerular , Humanos , Túbulos Renales Proximales/efectos de los fármacos , Túbulos Renales Proximales/patología , Túbulos Renales Proximales/fisiopatología , Ratones Noqueados , MicroARNs/genética , Fosforilación , Pronóstico , Proteínas Proto-Oncogénicas c-akt/metabolismo , Interferencia de ARN , Ratas Sprague-Dawley , Índice de Severidad de la Enfermedad , Transducción de Señal , Proteína smad7/genética , Transfección , Factor de Crecimiento Transformador beta1/farmacología , Regulación hacia ArribaRESUMEN
Despite the wealth of pre-clinical support for a role for reactive oxygen and nitrogen species (ROS/RNS) in the aetiology of diabetic complications, enthusiasm for antioxidant therapeutic approaches has been dampened by less favourable outcomes in large clinical trials. This has necessitated a re-evaluation of pre-clinical evidence and a more rational approach to antioxidant therapy. The present review considers current evidence, from both pre-clinical and clinical studies, to address the benefits of antioxidant therapy. The main focus of the present review is on the effects of direct targeting of ROS-producing enzymes, the bolstering of antioxidant defences and mechanisms to improve nitric oxide availability. Current evidence suggests that a more nuanced approach to antioxidant therapy is more likely to yield positive reductions in end-organ injury, with considerations required for the types of ROS/RNS involved, the timing and dosage of antioxidant therapy, and the selective targeting of cell populations. This is likely to influence future strategies to lessen the burden of diabetic complications such as diabetes-associated atherosclerosis, diabetic nephropathy and diabetic retinopathy.
Asunto(s)
Vasos Sanguíneos/metabolismo , Angiopatías Diabéticas/metabolismo , Nefropatías Diabéticas/metabolismo , Riñón/metabolismo , Estrés Oxidativo , Especies Reactivas de Oxígeno/metabolismo , Animales , Antioxidantes/uso terapéutico , Azoles/uso terapéutico , Vasos Sanguíneos/efectos de los fármacos , Angiopatías Diabéticas/tratamiento farmacológico , Angiopatías Diabéticas/etiología , Nefropatías Diabéticas/tratamiento farmacológico , Nefropatías Diabéticas/etiología , Retinopatía Diabética/tratamiento farmacológico , Retinopatía Diabética/etiología , Retinopatía Diabética/metabolismo , Diseño de Fármacos , Activación Enzimática , Activadores de Enzimas/uso terapéutico , Humanos , Isoindoles , Riñón/efectos de los fármacos , Terapia Molecular Dirigida , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa de Tipo III/metabolismo , Compuestos de Organoselenio/uso terapéutico , Estrés Oxidativo/efectos de los fármacos , Péptidos/uso terapéuticoRESUMEN
Diabetic nephropathy may occur, in part, as a result of intrarenal oxidative stress. NADPH oxidases comprise the only known dedicated reactive oxygen species (ROS)-forming enzyme family. In the rodent kidney, three isoforms of the catalytic subunit of NADPH oxidase are expressed (Nox1, Nox2, and Nox4). Here we show that Nox4 is the main source of renal ROS in a mouse model of diabetic nephropathy induced by streptozotocin administration in ApoE(-/-) mice. Deletion of Nox4, but not of Nox1, resulted in renal protection from glomerular injury as evidenced by attenuated albuminuria, preserved structure, reduced glomerular accumulation of extracellular matrix proteins, attenuated glomerular macrophage infiltration, and reduced renal expression of monocyte chemoattractant protein-1 and NF-κB in streptozotocin-induced diabetic ApoE(-/-) mice. Importantly, administration of the most specific Nox1/4 inhibitor, GKT137831, replicated these renoprotective effects of Nox4 deletion. In human podocytes, silencing of the Nox4 gene resulted in reduced production of ROS and downregulation of proinflammatory and profibrotic markers that are implicated in diabetic nephropathy. Collectively, these results identify Nox4 as a key source of ROS responsible for kidney injury in diabetes and provide proof of principle for an innovative small molecule approach to treat and/or prevent chronic kidney failure.
Asunto(s)
Diabetes Mellitus Experimental , Nefropatías Diabéticas , NADPH Oxidasas/antagonistas & inhibidores , Podocitos/enzimología , Pirazoles/farmacología , Piridinas/farmacología , Albuminuria/tratamiento farmacológico , Albuminuria/enzimología , Albuminuria/genética , Animales , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismo , Línea Celular Transformada , Diabetes Mellitus Experimental/tratamiento farmacológico , Diabetes Mellitus Experimental/enzimología , Diabetes Mellitus Experimental/genética , Nefropatías Diabéticas/tratamiento farmacológico , Nefropatías Diabéticas/enzimología , Nefropatías Diabéticas/genética , Modelos Animales de Enfermedad , Inhibidores Enzimáticos/farmacología , Matriz Extracelular/metabolismo , Silenciador del Gen , Glucosa/farmacología , Humanos , Macrófagos/metabolismo , Masculino , Ratones , Ratones Noqueados , NADH NADPH Oxidorreductasas/antagonistas & inhibidores , NADH NADPH Oxidorreductasas/genética , NADH NADPH Oxidorreductasas/metabolismo , NADPH Oxidasa 1 , NADPH Oxidasa 4 , NADPH Oxidasas/genética , NADPH Oxidasas/metabolismo , Podocitos/citología , Pirazolonas , Piridonas , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Renal fibrosis results from excessive accumulation of extracellular matrix mainly driven by transforming growth factor-ß1 (TGF-ß1). Certain microRNAs have been implicated in this disease, and here we examine the role of let-7b. Rat proximal tubular epithelial cells (NRK52E) were treated with TGF-ß1 for 3 days to assess the expression of markers of fibrosis and let-7b. These factors were also assessed in two mouse models representing early and more advanced diabetic nephropathy and in the non-diabetic adenine-induced renal fibrosis model. TGF-ß1 downregulated the expression of let-7b and induced fibrogenesis in NRK52E cells. Ectopic expression of let-7b repressed TGF-ß1 receptor 1 (TGFBR1) expression directly by targeting the two let-7b binding sites in the 3'-untranslated region of that gene, reduced expression of extracellular matrix proteins, decreased SMAD3 activity, and attenuated the profibrotic effects of TGF-ß1. Knockdown of let-7b elevated TGFBR1 expression and mimicked some of the profibrotic effects of TGF-ß1. Consistent with these observations, let-7b expression was also reduced in models of both diabetic and non-diabetic renal fibrosis with the upregulation of TGFBR1. Thus, let-7b microRNA represents a potential new target for the treatment of renal fibrosis in diabetic and non-diabetic nephropathy.
Asunto(s)
Nefropatías Diabéticas/metabolismo , Riñón/metabolismo , MicroARNs/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Receptores de Factores de Crecimiento Transformadores beta/metabolismo , Insuficiencia Renal Crónica/metabolismo , Factor de Crecimiento Transformador beta1/metabolismo , Regiones no Traducidas 3' , Adenina , Animales , Apolipoproteínas E/deficiencia , Apolipoproteínas E/genética , Sitios de Unión , Línea Celular , Nefropatías Diabéticas/genética , Nefropatías Diabéticas/patología , Modelos Animales de Enfermedad , Proteínas de la Matriz Extracelular/genética , Proteínas de la Matriz Extracelular/metabolismo , Fibrosis , Regulación de la Expresión Génica , Humanos , Riñón/patología , Túbulos Renales/metabolismo , Túbulos Renales/patología , Células Mesangiales/metabolismo , Células Mesangiales/patología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , MicroARNs/genética , Proteínas Serina-Treonina Quinasas/genética , Interferencia de ARN , Ratas , Receptor Tipo I de Factor de Crecimiento Transformador beta , Receptores de Factores de Crecimiento Transformadores beta/genética , Proteínas Recombinantes/metabolismo , Insuficiencia Renal Crónica/inducido químicamente , Insuficiencia Renal Crónica/genética , Insuficiencia Renal Crónica/patología , Transducción de Señal , Proteína smad3/metabolismo , Factores de Tiempo , Transfección , Factor de Crecimiento Transformador beta1/genéticaRESUMEN
Diabetic kidney disease (DKD) is a major microvascular complication of both type 1 and type 2 diabetes. DKD is characterised by injury to both glomerular and tubular compartments, leading to kidney dysfunction over time. It is one of the most common causes of chronic kidney disease (CKD) and end-stage renal disease (ESRD). Persistent high blood glucose levels can damage the small blood vessels in the kidneys, impairing their ability to filter waste and fluids from the blood effectively. Other factors like high blood pressure (hypertension), genetics, and lifestyle habits can also contribute to the development and progression of DKD. The key features of renal complications of diabetes include morphological and functional alterations to renal glomeruli and tubules leading to mesangial expansion, glomerulosclerosis, homogenous thickening of the glomerular basement membrane (GBM), albuminuria, tubulointerstitial fibrosis and progressive decline in renal function. In advanced stages, DKD may require treatments such as dialysis or kidney transplant to sustain life. Therefore, early detection and proactive management of diabetes and its complications are crucial in preventing DKD and preserving kidney function.
RESUMEN
Chronic hyperglycemia induces intrarenal oxidative stress due to the excessive production of reactive oxygen species (ROS), leading to a cascade of events that contribute to the development and progression of diabetic kidney disease (DKD). NOX5, a pro-oxidant NADPH oxidase isoform, has been identified as a significant contributor to renal ROS in humans. Elevated levels of renal ROS contribute to endothelial cell dysfunction and associated inflammation, causing increased endothelial permeability, which can disrupt the renal ecosystem, leading to progressive albuminuria and renal fibrosis in DKD. This study specifically examines the contribution of endothelial cell-specific human NOX5 expression in renal pathology in a transgenic mouse model of DKD. This study additionally compares NOX5 with the previously characterized NADPH oxidase, NOX4, in terms of their relative roles in DKD. Regardless of NOX4 pathway, this study found that endothelial cell-specific expression of NOX5 exacerbates renal injury, albuminuria and fibrosis. This is attributed to the activation of the endothelial mesenchymal transition (EMT) pathway via enhanced ROS formation and the modulation of redox-sensitive factors. These findings underscore the potential therapeutic significance of NOX5 inhibition in human DKD. The study proposes that inhibiting NOX5 could be a promising approach for mitigating the progression of DKD and strengthens the case for the development of NOX5-specific inhibitors as a potential therapeutic intervention.
RESUMEN
Excessive production of renal reactive oxygen species (ROS) plays a major role in diabetic kidney disease (DKD). Here, we provide key findings demonstrating the predominant pathological role of the pro-oxidant enzyme NADPH oxidase 5 (NOX5) in DKD, independent of the previously characterized NOX4 pathway. In patients with diabetes, we found increased expression of renal NOX5 in association with enhanced ROS formation and upregulation of ROS-sensitive factors early growth response 1 (EGR-1), protein kinase C-α (PKC-α), and a key metabolic gene involved in redox balance, thioredoxin-interacting protein (TXNIP). In preclinical models of DKD, overexpression of NOX5 in Nox4-deficient mice enhances kidney damage by increasing albuminuria and augmenting renal fibrosis and inflammation via enhanced ROS formation and the modulation of EGR1, TXNIP, ERK1/2, PKC-α, and PKC-ε. In addition, the only first-in-class NOX inhibitor, GKT137831, appears to be ineffective in the presence of NOX5 expression in diabetes. In vitro, silencing of NOX5 in human mesangial cells attenuated upregulation of EGR1, PKC-α, and TXNIP induced by high glucose levels, as well as markers of inflammation (TLR4 and MCP-1) and fibrosis (CTGF and collagens I and III) via reduction in ROS formation. Collectively, these findings identify NOX5 as a superior target in human DKD compared with other NOX isoforms such as NOX4, which may have been overinterpreted in previous rodent studies.
Asunto(s)
Diabetes Mellitus , Nefropatías Diabéticas , Animales , Nefropatías Diabéticas/genética , Nefropatías Diabéticas/metabolismo , Fibrosis , Humanos , Inflamación/metabolismo , Ratones , NADPH Oxidasa 4/genética , NADPH Oxidasa 5/genética , NADPH Oxidasa 5/metabolismo , NADPH Oxidasas/genética , NADPH Oxidasas/metabolismo , Especies Reactivas de Oxígeno/metabolismoRESUMEN
The prevalence of diabetes is growing at an alarming rate with increased disability, morbidity, and often premature mortality because of the various complications of this disorder. Chronic hyperglycemia, dyslipidemia, and other metabolic alterations lead to the development and progression of macro- and microvascular complications of diabetes including cardiovascular, retinal and kidney disease. Despite advances in glucose and lipid lowering treatments, a large number of diabetic individuals develop one or more types of these complications, ultimately leading to end-organ damage over the time. Atherosclerosis is the major macro-vascular complications of diabetes and the primary underlying cause of cardiovascular disease (CVD) posing heavy burden on the health care system. In this review, we discuss the involvement of dyslipidemia in the progression of atherosclerosis by activating the pro-inflammatory cytokines and oxidative stress-related factors. In addition, we also provide information on various pharmacological agents that provides protection against diabetic atherosclerosis by reducing inflammation and oxidative stress.
RESUMEN
Significance: Oxidative stress plays a critical role in the development and progression of serious micro- and macrovascular complications of diabetes. Nicotinamide adenine dinucleotide phosphate oxidase (NOX)-derived reactive oxygen species (ROS) significantly contribute to oxidative stress-associated inflammatory pathways that lead to tissue damage of different organs, including the kidneys, retina, brain, nerves, and the cardiovascular system. Recent Advances: Preclinical studies, including genetic-modified mouse models or cell culture models, have revealed the role of specific NOX isoforms in different diabetic complications, and suggested them as a promising target for the treatment of these diseases. Critical Issues: In this review, we provide an overview of the role of ROS and oxidative stress in macrovascular complications, such as stroke, myocardial infarction, coronary artery disease, and peripheral vascular disease that are all mainly driven by atherosclerosis, as well as microvascular complications, such as diabetic retinopathy, nephropathy, and neuropathy. We summarize conducted genetic deletion studies of different Nox isoforms as well as pharmacological intervention studies using NOX inhibitors in the context of preclinical as well as clinical research on diabetic complications. Future Directions: We outline the isoforms that are most promising for future clinical trials in the context of micro- and macrovascular complications of diabetes.
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Inhibidores Enzimáticos/farmacología , NADPH Oxidasas/antagonistas & inhibidores , Animales , Antiinflamatorios/farmacología , Antiinflamatorios/uso terapéutico , Antioxidantes/farmacología , Antioxidantes/uso terapéutico , Complicaciones de la Diabetes , Modelos Animales de Enfermedad , Inhibidores Enzimáticos/uso terapéutico , Humanos , NADPH Oxidasas/metabolismo , Oxidación-Reducción/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Oxidative stress and inflammation are considered major drivers in the pathogenesis of diabetic complications, including renal and cardiovascular disease. A symbiotic relationship also appears to exist between oxidative stress and inflammation. Several emerging therapies target these crucial pathways, to alleviate the burden of the aforementioned diseases. Oxidative stress refers to an imbalance between reactive oxygen species (ROS) and antioxidant defenses, a pathological state which not only leads to direct cellular damage but also an inflammatory cascade that further perpetuates tissue injury. Emerging therapeutic strategies tackle these pathways in a variety of ways, from increasing antioxidant defenses (antioxidants and Nrf2 activators) to reducing ROS production (NADPH oxidase inhibitors and XO inhibitors) or inhibiting the associated inflammatory pathways (NLRP3 inflammasome inhibitors, lipoxins, GLP-1 receptor agonists, and AT-1 receptor antagonists). This review summarizes the mechanisms by which oxidative stress and inflammation contribute to and perpetuate diabetes associated renal and cardiovascular disease along with the therapeutic strategies which target these pathways to provide reno and cardiovascular protection in the setting of diabetes.
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Overactivity of the sympathetic nervous system and high blood pressure are implicated in the development and progression of chronic kidney disease (CKD) and independently predict cardiovascular events in end-stage renal disease. To assess the role of renal nerves, we determined whether renal denervation (RDN) altered the hypertension and sympathoexcitation associated with a rabbit model of CKD. The model involves glomerular layer lesioning and uninephrectomy, resulting in renal function reduced by one-third and diuresis. After 3-week CKD, blood pressure was 13±2 mm Hg higher than at baseline (P<0.001), and compared with sham control rabbits, renal sympathetic nerve activity was 1.2±0.5 normalized units greater (P=0.01). The depressor response to ganglion blockade was also +8.0±3 mm Hg greater, but total norepinephrine spillover was 8.7±3.7 ng/min lower (both P<0.05). RDN CKD rabbits only increased blood pressure by 8.0±1.5 mm Hg. Renal sympathetic activity, the response to ganglion blockade and diuresis were similar to sham denervated rabbits (non-CKD). CKD rabbits had intact renal sympathetic baroreflex gain and range, as well as normal sympathetic responses to airjet stress. However, hypoxia-induced sympathoexcitation was reduced by -9±0.4 normalized units. RDN did not alter the sympathetic response to hypoxia or airjet stress. CKD increased oxidative stress markers Nox5 and MCP-1 (monocyte chemoattractant protein-1) in the kidney, but RDN had no effect on these measures. Thus, RDN is an effective treatment for hypertension in this model of CKD without further impairing renal function or altering the normal sympathetic reflex responses to various environmental stimuli.
Asunto(s)
Presión Sanguínea/fisiología , Hipertensión/fisiopatología , Riñón/inervación , Insuficiencia Renal Crónica/fisiopatología , Insuficiencia Renal/fisiopatología , Animales , Barorreflejo/fisiología , Desnervación , Modelos Animales de Enfermedad , Riñón/fisiopatología , Masculino , Conejos , SimpatectomíaRESUMEN
Hypertension is a risk factor for the vascular permeability and neovascularization that threatens vision in diabetic retinopathy. Excess reactive oxygen species derived from the Nox (NADPH oxidase) isoforms, Nox1 and Nox4, contributes to vasculopathy in diabetic retinopathy; however, if Nox1/4 inhibition is beneficial in hypertensive diabetic retinopathy is unknown. Here, we determined that diabetic spontaneously hypertensive rats had exacerbated retinal vascular permeability and expression of angiogenic and inflammatory factors, compared with normotensive diabetic Wistar Kyoto rats. GKT136901, a specific dual inhibitor of Nox1 and Nox4, prevented these events in diabetic Wistar Kyoto rats and spontaneously hypertensive rats. Retinal neovascularization does not develop in diabetic rodents, and therefore, the oxygen-induced retinopathy model is used to evaluate this pathology. We previously demonstrated that Nox1/4 inhibition reduced retinal neovascularization in oxygen-induced retinopathy. However, although Nox5 is expressed in human retina, its contribution to retinopathy has not been studied in vivo, largely due to its absence from the rodent genome. We generated transgenic mice with inducible human Nox5 expressed in endothelial cells (vascular endothelial-cadherin+Nox5+ mice). In vascular endothelial-cadherin+Nox5+ mice with oxygen-induced retinopathy, retinal vascular permeability and neovascularization, as well as the expression of angiogenic and inflammatory factors, were increased compared with wild-type littermates. In bovine retinal endothelial cells, which express Nox1, Nox4, and Nox5, Nox1/4 inhibition, as well as Nox5 silencing RNA, reduced the high glucose-induced upregulation of oxidative stress, angiogenic, and inflammatory factors. Collectively, these data indicate the potential of Nox1, Nox4, and Nox5 inhibition to reduce vision-threatening damage to the retinal vasculature.