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The chemotherapeutic agent, cisplatin, accumulates in the kidneys leading to acute kidney injury (AKI). Pre-clinical and clinical studies have demonstrated sex-dependent outcomes of cisplatin-AKI. Deranged histone deacetylase (HDAC) activity is hypothesized to promote the pathogenesis of male murine cisplatin-AKI; however, it is unknown if there are sex differences in the kidney HDACs. We hypothesized that there would be sex specific Hdac expression, localization, or enzymatic activity and this may explain sexual-dimorphic responses to cisplatin-AKI. In normal human kidney RNA samples, HDAC10 was significantly greater in the kidney of women compared to men, while HDAC1, HDAC6, HDAC10, and HDAC11 were differentially expressed between the kidney cortex and medulla, regardless of sex. In a murine model of cisplatin-AKI (3 days post a 15 mg/kg injection) we found few sex- or cisplatin- Hdac kidney transcript differences among the mice. Although Hdac9 was significantly greater in female mice compared to males, HDAC9 protein localization did not differ. Hdac7 transcripts were greater in the inner medulla of cisplatin-AKI mice, regardless of sex, and this agreed with a greater HDAC7 abundance. HDAC activity within the cortex, outer, and inner medullae was significantly lower in cisplatin-AKI mice but did not differ between the sexes. In agreement with these findings a class I HDAC inhibitor didn't improve kidney injury or function. In conclusion, even though cisplatin-AKI was evident and there were transcript level differences among the different kidney regions in this model, there were few sex or cisplatin-dependent effects on kidney HDAC localization or activity.
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The intrarenal endothelin (ET) system is an established moderator of kidney physiology and mechanistic contributor to the pathophysiology and progression of chronic kidney disease in humans and rodents. The aim of the present study was to characterize ET system by combining single cell RNA sequencing (scRNA-seq) data with immunolocalization in human and rodent kidneys of both sexes. Using publicly available scRNA-seq data, we assessed sex and kidney disease status (human), age and sex (rats), and diurnal expression (mice) on the kidney ET system expression. In normal human biopsies of both sexes and in rodent kidney samples, the endothelin-converting enzyme-1 (ECE1) and ET-1 were prominent in the glomeruli and endothelium. These data agreed with the scRNA-seq data from these three species, with ECE1/Ece1 mRNA enriched in the endothelium. However, the EDN1/Edn1 gene (encodes ET-1) was rarely detected, even though it was immunolocalized within the kidneys, and plasma and urinary ET-1 excretion are easily measured. Within each species, there were some sex-specific differences. For example, in kidney biopsies from living donors, men had a greater glomerular endothelial cell endothelin receptor B (Ednrb) compared with women. In mice, females had greater kidney endothelial cell Ednrb than male mice. As commercially available antibodies did not work in all species, and RNA expression did not always correlate with protein levels, multiple approaches should be considered to maintain required rigor and reproducibility of the pre- and clinical studies evaluating the intrarenal ET system.
Assuntos
Endotelina-1 , Enzimas Conversoras de Endotelina , Receptor de Endotelina B , Animais , Humanos , Masculino , Enzimas Conversoras de Endotelina/metabolismo , Enzimas Conversoras de Endotelina/genética , Feminino , Endotelina-1/metabolismo , Endotelina-1/genética , Camundongos , Receptor de Endotelina B/metabolismo , Receptor de Endotelina B/genética , Ratos , Rim/metabolismo , Endotelinas/metabolismo , Endotelinas/genética , Fatores Sexuais , Receptor de Endotelina A/metabolismo , Receptor de Endotelina A/genética , Análise de Célula Única , RNA-Seq , Glomérulos Renais/metabolismoRESUMO
Background: Disease severity of autosomal dominant polycystic kidney disease (ADPKD) is influenced by diet. Dietary protein, a recognized cyst-accelerating factor, is catabolized into amino acids (AA) and delivered to the kidney leading to renal hypertrophy. Injury-induced hypertrophic signaling in ADPKD results in increased macrophage (MФ) activation and inflammation followed by cyst growth. We hypothesize that the cystogenesis-prompting effects of HP diet are caused by increased delivery of specific AA to the kidney, ultimately stimulating MФs to promote cyst progression. Methods: Pkd1flox/flox mice with and without Cre (CAGG-ER) were given tamoxifen to induce global gene deletion (Pkd1KO). Pkd1KO mice were fed either a low (LP; 6%), normal (NP; 18%), or high (HP; 60%) protein diet for 1 week (early) or 6 weeks (chronic). Mice were then euthanized and tissues were used for histology, immunofluorescence and various biochemical assays. One week fed kidney tissue was cell sorted to isolate tubular epithelial cells for RNA sequencing. Results: Chronic dietary protein load in Pkd1KO mice increased kidney weight, number of kidney infiltrating and resident MФs, chemokines, cytokines and cystic index compared to LP diet fed mice. Accelerated cyst growth induced by chronic HP were attenuated by liposomal clodronate-mediated MФ depletion. Early HP diet fed Pkd1KO mice had larger cystic kidneys compared to NP or LP fed counterparts, but without increases in the number of kidney MФs, cytokines, or markers of tubular injury. RNA sequencing of tubular epithelial cells in HP compared to NP or LP diet group revealed increased expression of sodium-glutamine transporter Snat3, chloride channel Clcnka, and gluconeogenesis marker Pepck1, accompanied by increased excretion of urinary ammonia, a byproduct of glutamine. Early glutamine supplementation in Pkd1KO mice lead to kidney hypertrophy. Conclusion: Chronic dietary protein load-induced renal hypertrophy and accelerated cyst growth in Pkd1KO mice is dependent on both infiltrating and resident MФ recruitment and subsequent inflammatory response. Early cyst expansion by HP diet, however, is relient on increased delivery of glutamine to kidney epithelial cells, driving downstream metabolic changes prior to inflammatory provocation.
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It is critical to characterize the natural history of albuminuria in patients with sickle cell anemia (SCA); however, these data are currently lacking and affecting evidence-based guidelines. We performed a natural history study of the development of pediatric albuminuria. We identified participants with hemoglobin SS/SB0 thalassemia ≥5 years with albumin to creatinine ratio (ACR) measurements performed at a steady-state clinic visit. Participants were characterized as either persistent, intermittent, or never albuminuria. We determined the prevalence of persistent albuminuria, use of ACR ≥100 mg/g as a predictor, and variation in ACR measurements. We mirrored this study to determine the variation in albuminuria measurements in the SCA murine model. Among 355 participants with HbSS/SB0 thalassemia with 1728 ACR measurements, we identified 17% with persistent and 13% with intermittent albuminuria. Thirteen percent of participants with persistent albuminuria developed an abnormal ACR before 10 years of age. A single ACR measurement ≥100 mg/g was associated with 55.5 times (95% confidence interval, 12.3-527) higher odds of having persistent albuminuria. Among participants with ACR ≥100 mg/g, we identified significant variability in the results of repeated measurements. The median ACR at the initial and next measurements were 175.8 mg/g (interquartile range [IQR], 135-242) and 117.3 mg/g (IQR, 64-292). The human variability in ACR was mirrored by â¼20% variability in albuminuria in murine model. This evidence suggests adopting standards for repeating ACR measurements, consider screening for ACR before 10 years of age, and using an ACR >100 mg/g as a risk factor for progression. Pediatric and murine renoprotective clinical trials need to consider the high variability in repeated ACR measurements.
Assuntos
Anemia Falciforme , Talassemia , Humanos , Criança , Animais , Camundongos , Albuminúria/etiologia , Albuminúria/diagnóstico , Albuminúria/epidemiologia , Modelos Animais de Doenças , Taxa de Filtração Glomerular , Creatinina , Anemia Falciforme/epidemiologia , Hemoglobina FalciformeRESUMO
A hypercoagulable state, chronic inflammation, and increased risk of venous thrombosis and stroke are prominent features in patients with sickle cell disease (SCD). Coagulation factor XII (FXII) triggers activation of the contact system that is known to be involved in both thrombosis and inflammation, but not in physiological hemostasis. Therefore, we investigated whether FXII contributes to the prothrombotic and inflammatory complications associated with SCD. We found that when compared with healthy controls, patients with SCD exhibit increased circulating biomarkers of FXII activation that are associated with increased activation of the contact pathway. We also found that FXII, but not tissue factor, contributes to enhanced thrombin generation and systemic inflammation observed in sickle cell mice challenged with tumor necrosis factor α. In addition, FXII inhibition significantly reduced experimental venous thrombosis, congestion, and microvascular stasis in a mouse model of SCD. Moreover, inhibition of FXII attenuated brain damage and reduced neutrophil adhesion to the brain vasculature of sickle cell mice after ischemia/reperfusion induced by transient middle cerebral artery occlusion. Finally, we found higher FXII, urokinase plasminogen activator receptor, and αMß2 integrin expression in neutrophils of patients with SCD compared with healthy controls. Our data indicate that targeting FXII effectively reduces experimental thromboinflammation and vascular complications in a mouse model of SCD, suggesting that FXII inhibition may provide a safe approach for interference with inflammation, thrombotic complications, and vaso-occlusion in patients with SCD.
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Anemia Falciforme , Fator XII , Animais , Camundongos , Anemia Falciforme/complicações , Anemia Falciforme/metabolismo , Fator XII/metabolismo , Inflamação , Acidente Vascular Cerebral , Trombose/metabolismoRESUMO
Podocyte foot processes are an important cellular layer of the glomerular barrier that regulates glomerular permeability. Insulin via the protein kinase G type Iα (PKGIα) signaling pathway regulates the balance between contractility and relaxation (permeability) of the podocyte barrier by regulation of the actin cytoskeleton. This mechanism was shown to be disrupted in diabetes. Rho family guanosine-5'-triphosphates (GTPases) are dynamic modulators of the actin cytoskeleton and expressed in cells that form the glomerular filtration barrier. Thus, changes in Rho GTPase activity may affect glomerular permeability to albumin. The present study showed that Rho family GTPases control podocyte migration and permeability. Moreover these processes are regulated by insulin in PKGIα-dependent manner. Modulation of the PKGI-dependent activity of Rac1 and RhoA GTPases with inhibitors or small-interfering RNA impair glomerular permeability to albumin. We also demonstrated this mechanism in obese, insulin-resistant Zucker rats. We propose that PKGIα-Rac1-RhoA crosstalk is necessary in proper organization of the podocyte cytoskeleton and consequently the stabilization of glomerular architecture and regulation of filtration barrier permeability.
Assuntos
Proteína Quinase Dependente de GMP Cíclico Tipo I , Podócitos , Albuminas/metabolismo , Animais , Proteína Quinase Dependente de GMP Cíclico Tipo I/metabolismo , Citoesqueleto/metabolismo , Insulina/metabolismo , Permeabilidade , Podócitos/metabolismo , Ratos , Ratos Wistar , Ratos Zucker , Proteínas rac1 de Ligação ao GTP/metabolismo , Proteínas rho de Ligação ao GTP/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismoRESUMO
Progressive iron accumulation and renal impairment are prominent in both patients and mouse models of sickle cell disease (SCD). Endothelin A receptor (ETA) antagonism prevents this iron accumulation phenotype and reduces renal iron deposition in the proximal tubules of SCD mice. To better understand the mechanisms of iron metabolism in the kidney and the role of the ETA receptor in iron chelation and transport, we studied renal iron handling in a nonsickle cell iron overload model, heme oxygenase-1 (Hmox-1-/-) knockout mice. We found that Hmox-1-/- mice had elevated plasma endothelin-1 (ET-1), cortical ET-1 mRNA expression, and renal iron content compared with Hmox-1+/+ controls. The ETA receptor antagonist, ambrisentan, attenuated renal iron deposition, without any changes to anemia status in Hmox-1-/- mice. This was accompanied by reduced urinary iron excretion. Finally, ambrisentan had an important iron recycling effect by increasing the expression of the cellular iron exporter, ferroportin-1 (FPN-1), and circulating total iron levels in Hmox-1-/- mice. These findings suggest that the ET-1/ETA signaling pathway contributes to renal iron trafficking in a murine model of iron overload.
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Anemia Falciforme , Sobrecarga de Ferro , Anemia Falciforme/complicações , Anemia Falciforme/metabolismo , Animais , Antagonistas do Receptor de Endotelina A/farmacologia , Antagonistas do Receptor de Endotelina A/uso terapêutico , Antagonistas dos Receptores de Endotelina , Endotelina-1/metabolismo , Heme Oxigenase-1/genética , Heme Oxigenase-1/metabolismo , Ferro/metabolismo , Sobrecarga de Ferro/complicações , Sobrecarga de Ferro/metabolismo , Rim/metabolismo , Camundongos , Camundongos Knockout , Receptor de Endotelina A/genética , Receptor de Endotelina A/metabolismoRESUMO
Peroxiredoxin-2 (Prx-2) is a critical antioxidant protein in red blood cells (RBC). Prx-2 is oxidized to a disulfide covalently-bound dimer by H2 O2 , and then reduced back by the NADPH-dependent thioredoxin-thioredoxin reductase system. The reduction of oxidized Prx-2 is relatively slow in RBCs. Since Prx-2 is highly abundant, Prx-2s' peroxidase catalytic cycle is not considered to be limiting under normal conditions. However, whether Prx-2 recycling becomes limiting when RBCs are exposed to stress is not known. Using three different model systems characterized by increased oxidative damage to RBCs spanning the physiologic (endogenous RBCs of different ages), therapeutic (cold-stored RBCs in blood banks) and pathologic (RBCs from sickle cell disease (SCD) patients and humanized SCD mice) spectrum, basal levels of Prx-2 oxidation and Prx-2 recycling kinetics after addition of H2 O2 were determined. The reduction of oxidized Prx-2 was significantly slower in older versuin older versus younger RBCs, in RBCs stored for 4-5 weeks compared to 1 week, and in RBC from pediatric SCD patients compared to RBCs from control non-SCD patients. Similarly, the rate of Prx-2 recycling was slower in humanized SCD mice compared to WT mice. Treatment of RBC with carbon monoxide (CO) to limit heme-peroxidase activity had no effect on Prx-2 recycling kinetics. Treatment with glucose attenuated slowed Prx-2 recycling in older RBCs and SCD RBCs, but not stored RBCs. In conclusion, the reduction of oxidized Prx-2 can be further slowed in RBCs, which may limit the protection afforded by this antioxidant protein in settings associated with erythrocyte stress.
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Anemia Falciforme , Peroxirredoxinas , Idoso , Anemia Falciforme/metabolismo , Animais , Antioxidantes/metabolismo , Eritrócitos/metabolismo , Humanos , Camundongos , Peroxidase/metabolismo , Peroxirredoxinas/metabolismoRESUMO
Despite advancements in disease management, sickle cell nephropathy, a major contributor to mortality and morbidity in patients, has limited therapeutic options. Previous studies indicate hydroxyurea, a commonly prescribed therapy for sickle cell disease (SCD), can reduce renal injury in SCD but the mechanisms are uncertain. Because SCD is associated with reduced nitric oxide (NO) bioavailability, we hypothesized that hydroxyurea treatment would improve NO bioavailability in the humanized sickle cell mouse. Humanized male 12-wk-old sickle (HbSS) and genetic control (HbAA) mice were treated with hydroxyurea or regular tap water for 2 wk before renal and systemic NO bioavailability as well as renal injury were assessed. Untreated HbSS mice exhibited increased proteinuria, elevated plasma endothelin-1 (ET-1), and reduced urine concentrating ability compared with HbAA mice. Hydroxyurea reduced proteinuria and plasma ET-1 levels in HbSS mice. Untreated HbSS mice had reduced plasma nitrite and elevated plasma arginase concentrations compared with HbAA mice. Hydroxyurea treatment augmented plasma nitrite and attenuated plasma arginase in HbSS mice. Renal vessels isolated from HbSS mice also had elevated nitric oxide synthase 3 (NOS3) and arginase 2 expression compared with untreated HbAA mice. Hydroxyurea treatment did not alter renal vascular NOS3, however, renal vascular arginase 2 expression was significantly reduced. These data support the hypothesis that hydroxyurea treatment augments renal and systemic NO bioavailability by reducing arginase activity as a potential mechanism for the improvement on renal injury seen in SCD mice.
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Anemia Falciforme/tratamento farmacológico , Antidrepanocíticos/farmacologia , Hidroxiureia/farmacologia , Nefropatias/tratamento farmacológico , Rim/efeitos dos fármacos , Óxido Nítrico/metabolismo , Anemia Falciforme/genética , Anemia Falciforme/metabolismo , Animais , Arginase/metabolismo , Modelos Animais de Doenças , Hemoglobina A/genética , Hemoglobina A/metabolismo , Hemoglobina Falciforme/genética , Hemoglobina Falciforme/metabolismo , Hemoglobinas/genética , Hemoglobinas/metabolismo , Humanos , Rim/metabolismo , Rim/patologia , Nefropatias/genética , Nefropatias/metabolismo , Nefropatias/patologia , Masculino , Camundongos Transgênicos , Óxido Nítrico Sintase Tipo III/metabolismo , Proteinúria/tratamento farmacológico , Proteinúria/genética , Proteinúria/metabolismoRESUMO
Timing of food intake has become a critical factor in determining overall cardiometabolic health. We hypothesized that timing of food intake entrains circadian rhythms of blood pressure (BP) and renal excretion in mice. Male C57BL/6J mice were fed ad libitum or reverse feeding (RF) where food was available at all times of day or only available during the 12-h lights-on period, respectively. Mice eating ad libitum had a significantly higher mean arterial pressure (MAP) during lights-off compared to lights-on (113 ± 2 mmHg vs 100 ± 2 mmHg, respectively; P < 0.0001); however, RF for 6 days inverted the diurnal rhythm of MAP (99 ± 3 vs 110 ± 3 mmHg, respectively; P < 0.0001). In contrast to MAP, diurnal rhythms of urine volume and sodium excretion remained intact after RF. Male Bmal1 knockout mice (Bmal1KO) underwent the same feeding protocol. As previously reported, Bmal1KO mice did not exhibit a diurnal MAP rhythm during ad libitum feeding (95 ± 1 mmHg vs 92 ± 3 mmHg, lights-off vs lights-on; P > 0.05); however, RF induced a diurnal rhythm of MAP (79 ± 3 mmHg vs 95 ± 2 mmHg, lights-off vs lights-on phase; P < 0.01). Transgenic PERIOD2::LUCIFERASE knock-in mice were used to assess the rhythm of the clock protein PERIOD2 in ex vivo tissue cultures. The timing of the PER2::LUC rhythm in the renal cortex and suprachiasmatic nucleus was not affected by RF; however, RF induced significant phase shifts in the liver, renal inner medulla, and adrenal gland. In conclusion, the timing of food intake controls BP rhythms in mice independent of Bmal1, urine volume, or sodium excretion.
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Pressão Sanguínea , Ritmo Circadiano , Ingestão de Alimentos , Animais , Masculino , Camundongos , Fatores de Transcrição ARNTL/genética , Ritmo Circadiano/fisiologia , Ingestão de Alimentos/fisiologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , SódioRESUMO
BACKGROUND: Premenopausal women have a lower risk of hypertension compared to age-matched men and postmenopausal women. P2Y2 and P2Y4 purinoceptor can be considered potential contributors to hypertension due to their emerging roles in regulating renal tubular Na+ transport. Activation of these receptors inhibits epithelial Na+ channel activity (ENaC) via a phospholipase C (PLC)-dependent pathway resulting in natriuresis. We recently reported that activation of P2Y2 and P2Y4 receptors in the renal medulla by UTP promotes natriuresis in male and ovariectomized (OVX) rats, but not in ovary-intact females. This led us to hypothesize that ovary-intact females have greater basal renal medullary activity of P2 (P2Y2 and P2Y4) receptors regulating Na+ excretion compared to male and OVX rats. METHODS: To test our hypothesis, we determined (i) the effect of inhibiting medullary P2 receptors by suramin (750 µg/kg/min) on urinary Na+ excretion in anesthetized male, ovary-intact female, and OVX Sprague Dawley rats, (ii) mRNA expression and protein abundance of P2Y2 and P2Y4 receptors, and (iii) mRNA expression of their downstream effectors (PLC-1δ and ENaCα) in renal inner medullary tissues obtained from these three groups. We also subjected cultured mouse inner medullary collecting duct cells (segment 3, mIMCD3) to different concentrations of 17ß-estradiol (E2, 0, 10, 100, and 1000 nM) to test whether E2 increases mRNA expression of P2Y2 and P2Y4 receptors. RESULTS: Acute P2 inhibition attenuated urinary Na+ excretion in ovary-intact females, but not in male or OVX rats. We found that P2Y2 and P2Y4 mRNA expression was higher in the inner medulla from females compared to males or OVX. Inner medullary lysates showed that ovary-intact females have higher P2Y2 receptor protein abundance, compared to males; however, OVX did not eliminate this sex difference. We also found that E2 dose-dependently upregulated P2Y2 and P2Y4 mRNA expression in mIMCD3. CONCLUSION: These data suggest that ovary-intact females have enhanced P2Y2 and P2Y4-dependent regulation of Na+ handling in the renal medulla, compared to male and OVX rats. We speculate that the P2 pathway contributes to facilitated renal Na+ handling in premenopausal females.
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Canais Epiteliais de Sódio/metabolismo , Estradiol/metabolismo , Natriurese/fisiologia , Ovário/fisiologia , Receptores Purinérgicos P2Y2/metabolismo , Receptores Purinérgicos P2/metabolismo , Animais , Linhagem Celular , Relação Dose-Resposta a Droga , Canais Epiteliais de Sódio/genética , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Medula Renal/fisiologia , Masculino , Ovariectomia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores Purinérgicos P2/genética , Receptores Purinérgicos P2Y2/genética , Fatores Sexuais , Suramina/farmacologia , Fosfolipases Tipo C/genética , Fosfolipases Tipo C/metabolismoRESUMO
BACKGROUND: Sickle cell disease (SCD) is characterized by chronic hemolytic anemia, vaso-occlusive crises, chronic inflammation, and activation of coagulation. The clinical complications such as painful crisis, stroke, pulmonary hypertension, nephropathy and venous thromboembolism lead to cumulative organ damage and premature death. High molecular weight kininogen (HK) is a central cofactor for the kallikrein-kinin and intrinsic coagulation pathways, which contributes to both coagulation and inflammation. OBJECTIVE: We hypothesize that HK contributes to the hypercoagulable and pro-inflammatory state that causes end-organ damage and early mortality in sickle mice. METHODS: We evaluated the role of HK in the Townes mouse model of SCD. RESULTS/CONCLUSIONS: We found elevated plasma levels of cleaved HK in sickle patients compared to healthy controls, suggesting ongoing HK activation in SCD. We used bone marrow transplantation to generate wild type and sickle cell mice on a HK-deficient background. We found that short-term HK deficiency attenuated thrombin generation and inflammation in sickle mice at steady state, which was independent of bradykinin signaling. Moreover, long-term HK deficiency attenuates kidney injury, reduces chronic inflammation, and ultimately improves survival of sickle mice.
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Anemia Falciforme , Cininogênio de Alto Peso Molecular , Anemia Falciforme/complicações , Animais , Coagulação Sanguínea , Humanos , Rim , Camundongos , TrombinaRESUMO
The diurnal rhythms of sodium handling and blood pressure are thought to be regulated by clock genes, such as Bmal1. However, little is known about the regulation of these factors by Bmal1, especially in rats. Using a novel whole-body Bmal1 knockout rat model (Bmal1-/-), we hypothesized that time of day regulation of sodium excretion is dependent on Bmal1. Using telemetry to continuously record mean arterial pressure, we observed that male and female Bmal1-/- rats had significantly reduced mean arterial pressure over the course of 24 hours compared with littermate controls. The circadian mean arterial pressure pattern remained intact in both sexes of Bmal1-/- rats, which is in contrast to the Bmal1-/- mouse model. Male Bmal1-/- rats had no significant difference in baseline sodium excretion between 12-hour active and inactive periods, indicating a lack of diurnal control independent of maintained mean arterial pressure rhythms. Female Bmal1-/- rats, however, had significantly greater sodium excretion during the active versus inactive period similar to controls. Thus, we observed a clear dissociation between circadian blood pressure and control of sodium excretion that is sex dependent. These findings are consistent with a more robust ability of females to maintain control of sodium excretion, and furthermore, demonstrate a novel role for Bmal1 in control of diurnal blood pressure independent of sodium excretion.
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Fatores de Transcrição ARNTL/metabolismo , Ritmo Circadiano/fisiologia , Rim , Eliminação Renal/fisiologia , Sódio/metabolismo , Animais , Animais Geneticamente Modificados , Pressão Sanguínea/fisiologia , Feminino , Rim/metabolismo , Rim/fisiopatologia , Masculino , Camundongos , Ratos , Fatores SexuaisRESUMO
High salt intake (HS) is associated with obesity and insulin resistance. ET-1, a peptide released in response to HS, inhibits the actions of insulin on cultured adipocytes through ET-1 type B (ETB) receptors; however, the in vivo implications of ETB receptor activation on lipid metabolism and insulin resistance is unknown. We hypothesized that activation of ETB receptors in response to HS intake promotes dyslipidemia and insulin resistance. In normal salt (NS) fed rats, no significant difference in body mass or epididymal fat mass was observed between control and ETB deficient rats. After 2 weeks of HS, ETB-deficient rats had significantly lower body mass and epididymal fat mass compared to controls. Nonfasting plasma glucose was not different between genotypes; however, plasma insulin concentration was significantly lower in ETB-deficient rats compared to controls, suggesting improved insulin sensitivity. In addition, ETB-deficient rats had higher circulating free fatty acids in both NS and HS groups, with no difference in plasma triglycerides between genotypes. In a separate experiment, ETB-deficient rats had significantly lower fasting blood glucose and improved glucose and insulin tolerance compared to controls. These data suggest that ET-1 promotes adipose deposition and insulin resistance via the ETB receptor.
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Dislipidemias/metabolismo , Endotelina-1/metabolismo , Resistência à Insulina , Insulina/metabolismo , Receptor de Endotelina B/deficiência , Tecido Adiposo/metabolismo , Adiposidade , Animais , Glicemia/análise , Glicemia/metabolismo , Peso Corporal , Modelos Animais de Doenças , Dislipidemias/sangue , Dislipidemias/etiologia , Ácidos Graxos não Esterificados/sangue , Humanos , Insulina/sangue , Masculino , Mutação , Ratos , Ratos Transgênicos , Receptor de Endotelina B/genética , Cloreto de Sódio na Dieta/efeitos adversosAssuntos
Anemia Falciforme , Animais , Criança , Feminino , Taxa de Filtração Glomerular , Humanos , Masculino , CamundongosRESUMO
Hyperfiltration, highly prevalent early in sickle cell disease (SCD), is in part driven by an increase in ultrafiltration coefficient (Kf). The increase in Kf may be due to enlarged filtration surface area and/or increased glomerular permeability (Palb). Previous studies have demonstrated that endothelin-1 (ET-1) contributes to Palb changes in models of diabetes and SCD. Thus, we performed longitudinal studies of renal function to determine the relationship between ET-1 and glomerular size and Palb that may contribute to hyperfiltration in humanized sickle cell (HbSS) and control (HbAA) mice at 8-32 weeks of age. HbSS mice were characterized by significant increases in plasma and glomerular ET-1 expression in both sexes although this increase was significantly greater in males. HbSS glomeruli of both males and females presented with a progressive and significant increase in glomerular size, volume, and Kf During the onset of hyperfiltration, plasma and glomerular ET-1 expression were associated with a greater increase in glomerular size and Kf in HbSS mice, regardless of sex. The pattern of Palb augmentation during the hyperfiltration was also associated with an increase in glomerular ET-1 expression, in both male and female HbSS mice. However, the increase in Palb was significantly greater in males and delayed in time in females. Additionally, selective endothelin A receptor (ETA) antagonist prevented hyperfiltration in HbSS, regardless of sex. These results suggest that marked sex disparity in glomerular hyperfiltration may be driven, in part, by ET-1-dependent ultra-structural changes in filtration barrier components contributing to glomerular hyperfiltration in HbSS mice.
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Anemia Falciforme/metabolismo , Endotelina-1/metabolismo , Taxa de Filtração Glomerular , Nefropatias/metabolismo , Glomérulos Renais/metabolismo , Anemia Falciforme/genética , Anemia Falciforme/patologia , Anemia Falciforme/fisiopatologia , Animais , Modelos Animais de Doenças , Antagonistas do Receptor de Endotelina A/farmacologia , Feminino , Taxa de Filtração Glomerular/efeitos dos fármacos , Hemoglobina A/genética , Hemoglobinas/genética , Humanos , Nefropatias/etiologia , Nefropatias/patologia , Nefropatias/fisiopatologia , Glomérulos Renais/efeitos dos fármacos , Glomérulos Renais/patologia , Glomérulos Renais/fisiopatologia , Masculino , Camundongos Transgênicos , Mutação , Fenilpropionatos/farmacologia , Piridazinas/farmacologia , Fatores de Risco , Fatores Sexuais , Transdução de SinaisRESUMO
We previously reported that humanized sickle cell (HbSS) mice develop spontaneous nephropathy, a major cause of morbidity and mortality in sickle cell disease (SCD). Because sex-dependent protective mechanisms in SCD have been reported, we examined the course of nephropathy in male and female HbSS mice to determine contributors and/or predictors of disease severity. In male HbSS mice, glomerular filtration rate was characterized by a rapid onset of hyperfiltration and subsequent progressive decline of renal function over 20 weeks. Early tubular injury presented with increased excretion of kidney injury marker 1 (KIM-1), progressive loss of tubular brush border, and interstitial fibrosis that preceded the onset of glomerular damage, suggesting a tubuloglomerular mechanism of kidney injury in these mice. Additionally, we observed a strong association between the magnitude of hyperfiltration and the degree of long-term kidney injury in male HbSS mice. Unlike males, female HbSS mice did not demonstrate a significant loss of renal function or severe kidney damage during the time course of the study. These results suggest that magnitude of hyperfiltration predicts the onset of chronic kidney damage in male HbSS mice, whereas protective mechanisms in female HbSS mice delay the onset of SCD nephropathy.
Assuntos
Anemia Falciforme/patologia , Hemoglobina Falciforme/genética , Rim/patologia , Animais , Modelos Animais de Doenças , Feminino , Taxa de Filtração Glomerular , Receptor Celular 1 do Vírus da Hepatite A/análise , Humanos , Nefropatias/etiologia , Túbulos Renais Proximais/patologia , Estudos Longitudinais , Masculino , Proteínas de Membrana/urina , Camundongos , Camundongos Endogâmicos C57BL , Camundongos TransgênicosRESUMO
Deranged histone deacetylase (HDAC) activity causes uncontrolled proliferation, inflammation, fibrosis, and organ damage. It is unclear whether deranged HDAC activity results in acute kidney injury in the renal hypoperfusion model of bilateral ischemia-reperfusion injury (IRI) and whether in vivo inhibition is an appropriate therapeutic approach to limit injury. Male mice were implanted with intraperitoneal osmotic minipumps containing vehicle, the class I HDAC inhibitor, MS275, or the pan-HDAC inhibitor, trichostatin A (TSA), 3 days before sham/bilateral IRI surgery. Kidney cortical samples were analyzed using histological, immunohistochemical, and Western blotting techniques. HDAC-dependent proliferation rate was measured in immortalized rat epithelial cells and primary mouse or human proximal tubule (PT) cells. There were dynamic changes in cortical HDAC localization and abundance following IRI including a fourfold increase in HDAC4 in the PT. HDAC inhibition resulted in a significantly higher plasma creatinine, increased kidney damage, but reduced interstitial fibrosis compared with vehicle-treated IRI mice. HDAC-inhibited mice had reduced interstitial α-smooth muscle actin, fibronectin expression, and Sirius red-positive area, suggesting that IRI activates HDAC-mediated fibrotic pathways. In vivo proliferation of the kidney epithelium was significantly reduced in TSA-treated, but not MS275-treated, IRI mice, suggesting class II HDACs mediate proliferation. Furthermore, HDAC4 activation increased proliferation of human and mouse PTs. Kidney HDACs are activated during IRI with isoform-specific expression patterns. Our data point to mechanisms whereby IRI activates HDACs resulting in fibrotic pathways but also activation of PT proliferation and repair pathways. This study demonstrates the need to develop isoform-selective HDAC inhibitors for the treatment of renal hypoperfusion-induced injury.
Assuntos
Injúria Renal Aguda/enzimologia , Proliferação de Células , Células Epiteliais/enzimologia , Histona Desacetilases/metabolismo , Túbulos Renais Proximais/enzimologia , Traumatismo por Reperfusão/enzimologia , Injúria Renal Aguda/tratamento farmacológico , Injúria Renal Aguda/patologia , Animais , Autofagia , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Modelos Animais de Doenças , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/patologia , Inibidores de Histona Desacetilases/farmacologia , Túbulos Renais Proximais/efeitos dos fármacos , Túbulos Renais Proximais/patologia , Masculino , Camundongos Endogâmicos C57BL , Ratos , Traumatismo por Reperfusão/tratamento farmacológico , Traumatismo por Reperfusão/patologia , Transdução de Sinais , Fatores de TempoRESUMO
BACKGROUND: In patients with diabetes mellitus, hyperfiltration precedes the development of albuminuria. Pediatric sickle cell anemia (SCA) patients have a high prevalence of hyperfiltration and albuminuria during early childhood and adolescence. We tested the hypothesis that hyperfiltration precedes the development of albuminuria in a longitudinal pediatric SCA cohort. METHODS: We identified 91 participants with HbSS or SB0 thalassemia 5-21 years of age enrolled in a longitudinal sickle cell nephropathy cohort study who had a cystatin C measured during early childhood (4-10 years of age). Early hyperfiltration was defined as a mean eGFR >180 mL/min/1.73m2 using cystatin C obtained from 4 to 10 years of age. Persistent albuminuria was defined as an albumin to creatinine ratio > 30 mg/g on two of three untimed urine specimens. Time to event analysis estimated survival curves for participants with and without hyperfiltration using Kaplan-Meier curves and used logrank test for categorical variables to assess the association with time to development of the first episode persistent albuminuria. RESULTS: Persistent albuminuria occurred more often and at an earlier age in participants with early hyperfiltration compared to those without early hyperfiltration (log-rank, P = .004). Participants who developed albuminuria have a significant increase in their eGFR during childhood (P = .003) as compared to participants who have not yet progressed to albuminuria (P = .26). For every 1 g/dL increase in hemoglobin, the hazard ratio for developing persistent proteinuria decreased by 0.56 (95% CI: 0.3, 1.06, P = .07). CONCLUSION: Hyperfiltration precedes the development of persistent proteinuria in pediatric SCA patients. Intervention strategies should target lowering eGFR during early childhood.
Assuntos
Albuminúria , Anemia Falciforme , Taxa de Filtração Glomerular , Nefropatias , Adolescente , Adulto , Albuminúria/etiologia , Albuminúria/metabolismo , Albuminúria/mortalidade , Albuminúria/fisiopatologia , Anemia Falciforme/complicações , Anemia Falciforme/metabolismo , Anemia Falciforme/mortalidade , Anemia Falciforme/fisiopatologia , Criança , Pré-Escolar , Intervalo Livre de Doença , Feminino , Humanos , Nefropatias/etiologia , Nefropatias/metabolismo , Nefropatias/mortalidade , Nefropatias/fisiopatologia , Masculino , Estudos Prospectivos , Taxa de SobrevidaRESUMO
AIM: Chronic high salt intake exaggerates renal injury and inflammation, especially with the loss of functional ETB receptors. Tauroursodeoxycholic acid (TUDCA) is a chemical chaperone and bile salt that is approved for the treatment of hepatic diseases. Our aim was to determine whether TUDCA is reno-protective in a model of ETB receptor deficiency with chronic high salt-induced renal injury and inflammation. METHODS: ETB -deficient and transgenic control rats were placed on normal (0.8% NaCl) or high salt (8% NaCl) diet for 3 weeks, receiving TUDCA (400 mg/kg/d; ip) or vehicle. Histological and biochemical markers of kidney injury, renal cell death and renal inflammation were assessed. RESULTS: In ETB -deficient rats, high salt diet significantly increased glomerular and proximal tubular histological injury, proteinuria, albuminuria, excretion of tubular injury markers KIM-1 and NGAL, renal cortical cell death and renal CD4+ T cell numbers. TUDCA treatment increased proximal tubule megalin expression as well as prevented high salt diet-induced glomerular and tubular damage in ETB -deficient rats, as indicated by reduced kidney injury markers, decreased glomerular permeability and proximal tubule brush border restoration, as well as reduced renal inflammation. However, TUDCA had no significant effect on blood pressure. CONCLUSIONS: TUDCA protects against the development of glomerular and proximal tubular damage, decreases renal cell death and inflammation in the renal cortex in rats with ETB receptor dysfunction on a chronic high salt diet. These results highlight the potential use of TUDCA as a preventive tool against chronic high salt induced renal damage.