RESUMEN
Although several studies have shown that glucocorticoids exert diuretic effects in animals and humans, the underlying mechanism responsible for the acute diuretic effect remains obscure. Here we examined the mechanism in terms of gene-expression. We observed that glucocorticoids, including dexamethasone (Dex) and prednisolone (PSL), acutely induced diuresis in rats in a dose-dependent manner. Free water clearance values were negative after Dex or PSL treatment, similar to those observed after treatment with osmotic diuretics (furosemide and acetazolamide). Dex significantly increased the urinary excretion of sodium, potassium, chloride, glucose, and inorganic phosphorus. Renal microarray analysis revealed that Dex significantly altered the renal expression of genes related to transmembrane transport activity. The mRNA levels of sodium/phosphate (NaPi-2a/Slc34a1, NaPi-2b/Slc34a2, and NaPi-2c/Slc34a3) and sodium/glucose cotransporters (Sglt2/Slc5a2) were significantly reduced in the Dex-treated kidney, being negatively correlated with the urinary excretion of their corresponding solutes. Dex did not affect renal expression of the natriuretic peptide receptor 1 (Npr1) gene, or the expression, localization, and phosphorylation of aquaporin-2 (AQP2), a water channel protein. These findings suggest that the acute diuretic effects of glucocorticoids might be mediated by reduced expression of sodium-dependent cotransporter genes.
Asunto(s)
Acuaporina 2 , Dexametasona , Diuresis , Expresión Génica , Glucocorticoides , Riñón , Animales , Glucocorticoides/farmacología , Diuresis/efectos de los fármacos , Masculino , Riñón/metabolismo , Riñón/efectos de los fármacos , Dexametasona/farmacología , Acuaporina 2/genética , Acuaporina 2/metabolismo , Expresión Génica/efectos de los fármacos , Expresión Génica/genética , Prednisolona/farmacología , Prednisolona/administración & dosificación , Relación Dosis-Respuesta a Droga , Ratas , Diuréticos/farmacología , Diuréticos/administración & dosificación , Transportador 2 de Sodio-Glucosa/genética , Transportador 2 de Sodio-Glucosa/metabolismo , ARN Mensajero/metabolismo , ARN Mensajero/genética , Ratas Sprague-Dawley , Ratas Wistar , Proteínas Cotransportadoras de Sodio-Fosfato/genética , Sodio/orina , Sodio/metabolismoRESUMEN
The aim of this study was to evaluate the involvement of nanoparticles prepared from Allium cepa L. as anti-inflammatory agents. In the present study, we identified nanoparticles from Allium cepa L. using the ultracentrifugation exosome purification method. The nanoparticles were referred to as 17,000× g and 200,000× g precipitates, and they contained quercetins, proteins, lipids, and small-sized RNA. The nanoparticles inhibited nitric oxide production from lipopolysaccharide (LPS)-stimulated RAW264 cells without cytotoxic properties. Cellular incorporation was confirmed by laser microscopic observation after PKH26 staining. The inhibition of caveolae-dependent endocytosis and macropinocytosis significantly prevented the incorporation of the nanoparticles but had no effect on the inhibition of nitric oxide in RAW264 cells. Collectively, the identified nanoparticles were capable of inhibiting the LPS response via extracellular mechanisms. Taken together, the way of consuming Allium cepa L. without collapsing the nanoparticles is expected to provide an efficient anti-inflammatory effect.
Asunto(s)
Endocitosis , Espacio Intracelular/metabolismo , Nanopartículas/química , Nitratos/metabolismo , Cebollas/química , Animales , Clatrina/metabolismo , Lipopolisacáridos , Ratones , Óxido Nítrico/biosíntesis , Quercetina/análisis , Células RAW 264.7RESUMEN
Urinary exosomes, small extracellular vesicles present in urine, are secreted from all types of renal epithelial cells. Aquaporin-2 (AQP2), a vasopressin-regulated water channel protein, is known to be selectively excreted into the urine through exosomes (UE-AQP2), and its renal expression is decreased in nephrotic syndrome. However, it is still unclear whether excretion of UE-AQP2 is altered in nephrotic syndrome. In this study, we examined the excretion of UE-AQP2 in an experimental rat model of nephrotic syndrome induced by the administration of puromycin aminonucleoside (PAN). Rats were assigned to two groups: a control group administered saline and a PAN group given a single intraperitoneal injection of PAN (125 mg/kg) at day 0. The experiment was continued for 8 days, and samples of urine, blood, and tissue were collected on days 2, 5, and 8. The blood and urine parameters revealed that PAN induced nephrotic syndrome on days 5 and 8, and decreases in the excretion of UE-AQP2 were detected on days 2 through 8 in the PAN group. Immunohistochemistry showed that the renal expression of AQP2 was decreased on days 5 and 8. The release of exosomal marker proteins into the urine through UEs was decreased on day 5 and increased on day 8. These data suggest that UE-AQP2 is decreased in PAN-induced nephrotic syndrome and that this reflects its renal expression in the marked proteinuria phase after PAN treatment.
Asunto(s)
Acuaporina 2/orina , Exosomas/metabolismo , Síndrome Nefrótico/orina , Puromicina Aminonucleósido/efectos adversos , Animales , Acuaporina 2/sangre , Biomarcadores/sangre , Biomarcadores/orina , Modelos Animales de Enfermedad , Regulación hacia Abajo , Inyecciones Intraperitoneales , Masculino , Síndrome Nefrótico/sangre , Síndrome Nefrótico/inducido químicamente , Puromicina Aminonucleósido/administración & dosificación , RatasRESUMEN
BACKGROUND: Diuresis has been observed within a week following renal transplantation, suggesting that the procedure causes acute disturbance of renal water homeostasis. Aquaporin (AQP) 1 and AQP2, important proteins for renal water reabsorption, have been identified in urinary extracellular vesicles (uEV-AQP1 and -AQP2), and experimental studies have shown that the presence of uEV-AQP1 and -AQP2 may be an indicator of their levels of expression in the kidney. However, the release patterns of uEV-AQP1 and -AQP2 during the acute phase following renal transplantation are largely unknown. METHODS: In this study, we examined the release of uEV-AQP1 and -AQP2 in recipients until 6 days (day 6) after renal transplantation. At Miyazaki prefectural Miyazaki Hospital, Japan, uEVs were obtained from 7 recipients, all of whom had received renal allografts from living donors. uEVs were isolated by differential centrifugation. RESULTS: Immunoblotting analysis showed that the release of uEV-AQP2 was significantly decreased on day 1 in comparison with a control sample (from 3 healthy volunteers), accompanied by high urine output and low urine osmolality. Thereafter, the level increased gradually to the control level by day 6. The release pattern of uEV-AQP1 was similar to that of uEV-AQP2, but the levels did not reach statistical significance in comparison with the control level at any of the time points examined. Evaluation of the relationship between urinary osmolality and uEV-AQPs revealed a significant correlation for uEV-AQP2, but not for uEV-AQP1. CONCLUSION: These results indicate that acute diuresis after renal transplantation might be due to a decrease in the renal expression of AQP2, whose level can be estimated from the amount released in uEVs.
Asunto(s)
Acuaporina 1/metabolismo , Acuaporina 2/metabolismo , Vesículas Extracelulares/metabolismo , Trasplante de Riñón , Complicaciones Posoperatorias , Reabsorción Renal/fisiología , Adulto , Femenino , Humanos , Fallo Renal Crónico/cirugía , Trasplante de Riñón/efectos adversos , Trasplante de Riñón/métodos , Masculino , Persona de Mediana Edad , Cuidados Posoperatorios/métodos , Complicaciones Posoperatorias/diagnóstico , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/metabolismo , Urinálisis/métodos , Desequilibrio Hidroelectrolítico/diagnóstico , Desequilibrio Hidroelectrolítico/etiología , Desequilibrio Hidroelectrolítico/metabolismoRESUMEN
Acute kidney injury (AKI) is an important risk factor for the development of chronic kidney disease (CKD), and an alteration in renal water handling has been observed during the transition of AKI to CKD. Urinary exosomal release of aquaporin-1 (AQP1) and AQP2, important proteins for renal water handling, has recently been reported to predict their levels of renal expression. Therefore, we examined the patterns of urinary exosomal release of AQP1 and AQP2, and the exosomal marker proteins tumor susceptibility 101 protein (TSG101) and ALG-2 interacting protein X (Alix), in the acute and chronic phases following induction of AKI by renal bilateral ischemia/reperfusion (I/R) in rats. Blood tests and histological examinations indicated that AKI occurred before at 7 days after renal I/R ( day 7) and that renal fibrosis developed progressively thereafter. Immunoblotting demonstrated significant decreases in the urinary exosomal release of AQP1 and AQP2 during severe AKI. Urinary exosomal release of Alix and TSG101 was significantly increased on day 7. These data were also confirmed in rats with unilateral renal I/R causing more serious AKI. Urinary exosomal release of either the Ser-256- or Ser-269-phosphorylated form of AQP2, both of which are involved in apical trafficking of AQP2, was positively correlated with that of total AQP2. These results suggest that urinary exosomal release of AQP1 and AQP2 is reduced in I/R-induced AKI, whereas that of Alix and TSG101 is increased in the initial phase of renal fibrosis. Furthermore, apical trafficking of AQP2 appears to be related to urinary exosomal release of AQP2.
Asunto(s)
Lesión Renal Aguda/orina , Acuaporina 1/orina , Acuaporina 2/orina , Exosomas/metabolismo , Riñón/metabolismo , Eliminación Renal , Daño por Reperfusión/orina , Lesión Renal Aguda/patología , Animales , Proteínas de Unión al Calcio/orina , Proteínas de Unión al ADN/orina , Modelos Animales de Enfermedad , Complejos de Clasificación Endosomal Requeridos para el Transporte/orina , Fibrosis , Riñón/patología , Masculino , Fosforilación , Transporte de Proteínas , Ratas Sprague-Dawley , Daño por Reperfusión/patología , Factores de Tiempo , Factores de Transcripción/orinaRESUMEN
BACKGROUND: Renal aquaporin-1 (AQP1), a water channel protein, is known to be secreted into urine, conveyed by nano-sized extracellular vesicles called exosomes. A previous study has demonstrated that acetazolamide (AZ), a diuretic that inhibits carbonic anhydrases, alters the expression level of AQP1 in cultured cells. Here we investigated whether AZ alters the release of urinary exosomal AQP1 in vivo. METHODS: The effect of AZ on urinary exosomal AQP1 secretion was examined in rats and compared with furosemide (another diuretic), NaHCO3 (an alkalizing agent) and NH4Cl (an acidifying agent). Urine, blood and kidney samples were obtained 2 h after each treatment. Urinary exosomes were isolated by a differential centrifugation technique and urinary exosomal proteins were analyzed by immunoblotting. RESULTS: The release of exosomal AQP1 into urine was markedly increased after treatment with AZ, accompanied by alkaluria and metabolic acidosis. Immunohistochemistry clearly demonstrated that AZ increased the apical membrane expression of AQP1 in the proximal tubules. AZ did not affect the release of exosomal marker proteins (tumor susceptibility gene 101 protein and apoptosis-linked gene 2 interacting protein X). Treatment with furosemide did not change, whereas NaHCO3 and NH4Cl decreased the exosomal release of AQP1. CONCLUSION: The present findings indicate that AZ increases the release of exosomal AQP1 into urine in association with enhanced apical membrane expression of AQP1.
Asunto(s)
Acetazolamida/farmacología , Acuaporina 1/orina , Diuréticos/farmacología , Animales , Evaluación Preclínica de Medicamentos , Exosomas/metabolismo , Furosemida/farmacología , Concentración de Iones de Hidrógeno , Riñón/efectos de los fármacos , Riñón/metabolismo , Masculino , Ratas Sprague-DawleyRESUMEN
Since the successful characterization of urinary extracellular vesicles (uEVs) by Knepper's group in 2004, these vesicles have been a focus of intense basic and translational research worldwide, with the aim of developing novel biomarkers and therapeutics for renal disease. Along with these studies, there is growing evidence that aquaporins (AQPs), water channel proteins, in uEVs have the potential to be diagnostically useful. In this review, we highlight current knowledge of AQPs in uEVs from their discovery to clinical application.
Asunto(s)
Acuaporinas/orina , Exosomas/metabolismo , Enfermedades Renales/orina , Acuaporinas/metabolismo , Biomarcadores/metabolismo , Biomarcadores/orina , Humanos , Enfermedades Renales/metabolismoRESUMEN
Urinary exosomes are nano-sized vesicles secreted into urine from all types of renal epithelial cells and are known to contain possible biomarker proteins for renal diseases. Gentamicin has been reported to decrease the level of renal aquaporin (AQP)2, which is known to be mainly expressed in renal collecting ducts and excreted into the urine via exosomes. In the present study, we investigated whether urinary exosomal AQP2 could serve as a potential biomarker for gentamicin-induced nephrotoxicity, especially collecting duct cell dysfunction. Gentamicin was given to rats intraperitoneally once every day starting on day 0. Gentamicin significantly increased the plasma creatinine concentration from day 5 and beyond. Also, gentamicin induced polyuria and a defective urine concentration mechanism on day 7, suggesting gentamicin-induced collecting duct cell dysfunction. Immunoblot analysis showed that gentamicin significantly increased urinary exosomal AQP2 excretion on day 1 but decreased it on day 7 compared with the control group. Similarly, increased excretion of exosomal tumor susceptibility gene 101 protein, frequently used as an exosome marker protein, was observed on day 1. However, gentamicin did not significantly affect the urinary excretion of exosomal tumor susceptibility gene 101 on day 7. Gentamicin slightly decreased renal AQP2 expression on day 2 and markedly decreased it on day 8. These data strongly suggest that the use of urinary exosomal AQP2 as a biomarker may allow detection of gentamicin-induced collecting duct cell dysfunction. Furthermore, urinary exosomal AQP2 might also be useful for the early detection of gentamicin-induced renal injury in addition to collecting duct injury.
Asunto(s)
Antibacterianos/farmacología , Acuaporina 2/orina , Exosomas/metabolismo , Gentamicinas/farmacología , Animales , Antibacterianos/toxicidad , Peso Corporal/efectos de los fármacos , Proteínas de Unión al Calcio/metabolismo , Proteínas de Unión al ADN/metabolismo , Complejos de Clasificación Endosomal Requeridos para el Transporte/metabolismo , Exosomas/efectos de los fármacos , Gentamicinas/toxicidad , Masculino , Ratas , Ratas Sprague-Dawley , Factores de Transcripción/metabolismoRESUMEN
The role of aquaporin proteins (AQPs) in tumor biology has attracted attention over the past 20 years. However, the expression profiles of AQPs in canine sebaceous gland tumors remain obscure. This study was performed to clarify the expression of AQP1, 3, 5, the most studied AQPs in tumor biology, in sebaceous adenoma and sebaceous epithelioma. Among these AQPs, only AQP3 was expressed in normal tissue and both tumor types and located to only undifferentiated sebocytes (basaloid cells). A cellular proliferation marker, Ki67, was detected only in the area including basaloid cells in both tumor types. These findings suggest that AQP3 is useful for clarifying the origin of sebaceous gland tumors, and that AQP3 may be related to sebaceous gland development.
RESUMEN
Aquaporins (AQPs) are water channel proteins, and the expression of AQPs in carcinoma cells has received much attention over the last 15 years. In the veterinary field, however, little is known about the expression of AQPs. In the present study using immunohistochemistry, we examined the expression of AQP1, AQP3, and AQP5 in canine mammary gland carcinomas. The 27 samples comprised 10 grade I, 12 grade II, and 5 grade III samples (See Materials and Methods section for grade classification method). AQP1 was expressed in only 2 of the grade III carcinomas, and the expression was limited to spindle-shaped cells in the solid structure and on the outside of the solid mass. AQP3-positive cells were observed in 20 of 22 grade I and II samples. On the other hand, among grade III carcinomas, AQP3 was expressed only in spindle-shaped cells in 1 sample. AQP5 was expressed in all grade I and II carcinomas but not in the grade III tumors. In addition, enhanced expression of basolateral AQP3 and apical AQP5 was observed in lobular hyperplastic cells. These results suggest that the expression patterns of AQP3 and AQP5 can be of help for judging the grading of canine mammary tumors and that AQP1 is likely to be involved in metastasis. Moreover, AQP3 and AQP5 might be relevant to lactation in female dogs.
Asunto(s)
Carcinoma , Enfermedades de los Perros , Animales , Femenino , Perros , Inmunohistoquímica , Lactancia , Carcinoma/veterinariaRESUMEN
Urinary exosomes are small vesicles secreted into urine from all renal epithelial cell types and known to contain proteins that are involved in renal secretion and reabsorption. Among these proteins, urinary exosomal aquaporin-2 (AQP2) has been suggested to be useful for diagnosis of renal disease. However, the mechanisms underlying the excretion of urinary exosomal AQP2 are largely unknown. In this study, we examined the mechanisms of urinary exosomal AQP2 excretion in vivo, using diuretics including furosemide (FS), an inhibitor of the sodium-potassium-chloride symporter; acetazolamide (ACTZ), an inhibitor of carbonic anhydrase; OPC-31260 (OPC), a vasopressin type 2 receptor antagonist; and NaHCO3, a urinary alkalizing agent. Samples of urine from rats were collected for 2 h just after treatment with each diuretic, and urinary exosomes were isolated by ultracentrifugation. Urinary exosomal AQP2 excretion was dramatically increased by treatment with FS accompanied by urine acidification or with ACTZ accompanied by urine alkalization. Immunohistochemistry showed that apical localization of AQP2 was clearly evident and the plasma vasopressin level was increased after each treatment. Although treatment with OPC alone had no significant effect, coadministration of OPC completely inhibited the FS-induced and partially reduced the ACTZ-induced responses, respectively. Treatment with NaHCO3 increased the excretion of urinary exosomal AQP2 accompanied by urine alkalization. This increased response was partially inhibited by coadministration of OPC. These data suggest that an increased plasma level of vasopressin promoted the excretion of urinary exosomal AQP2 and that urine alkalinization also increased it independently of vasopressin.
Asunto(s)
Acuaporina 2/orina , Exosomas/metabolismo , Riñón/metabolismo , Vasopresinas/sangre , Álcalis/farmacología , Animales , Antagonistas de los Receptores de Hormonas Antidiuréticas , Diuréticos/farmacología , Exosomas/efectos de los fármacos , Antagonistas de Hormonas/farmacología , Concentración de Iones de Hidrógeno , Riñón/efectos de los fármacos , Masculino , Ratas , Ratas Sprague-Dawley , Receptores de Vasopresinas/metabolismo , Factores de TiempoRESUMEN
Aquaporin 11 (AQP11) is a newly described member of the protein family of transport channels. AQP11 associates with the endoplasmic reticulum (ER) and is highly expressed in proximal tubular epithelial cells in the kidney. Previously, we identified and characterized a recessive mutation of the highly conserved Cys227 to Ser227 in mouse AQP11 that caused proximal tubule (PT) injury and kidney failure in mutant mice. The current study revealed induction of ER stress, unfolded protein response, and apoptosis as molecular mechanisms of this PT injury. Cys227Ser mutation interfered with maintenance of AQP11 oligomeric structure. AQP11 is abundantly expressed in the S1 PT segment, a site of major renal glucose flux, and Aqp11 mutant mice developed PT-specific mitochondrial injury. Glucose increased AQP11 protein expression in wild-type kidney and upregulation of AQP11 expression by glucose in vitro was prevented by phlorizin, an inhibitor of sodium-dependent glucose transport across PT. Total AQP11 levels in heterozygotes were higher than in wild-type mice but were not further increased in response to glucose. In Aqp11 insufficient PT cells, glucose potentiated increases in reactive oxygen species (ROS) production. ROS production was also elevated in Aqp11 mutation carriers. Phenotypically normal mice heterozygous for the Aqp11 mutation repeatedly treated with glucose showed increased blood urea nitrogen levels that were prevented by the antioxidant sulforaphane or by phlorizin. Our results indicate an important role for AQP11 to prevent glucose-induced oxidative stress in proximal tubules.
Asunto(s)
Acuaporinas/genética , Retículo Endoplásmico/metabolismo , Riñón/metabolismo , Estrés Oxidativo/genética , Insuficiencia Renal/genética , Animales , Acuaporinas/metabolismo , Línea Celular , Estrés del Retículo Endoplásmico/fisiología , Ratones , Mutación , Especies Reactivas de Oxígeno/metabolismo , Insuficiencia Renal/metabolismo , Regulación hacia ArribaRESUMEN
BACKGROUND/AIM: Tears secreted from the lacrimal gland are essential for preserving the ocular surface. Thus, dysfunction of the lacrimal gland in Sjögren's syndrome (SS) can lead to dry eye, resulting in a reduced quality of life. We previously reported that blueberry 'leaf' water extract prevents lacrimal hyposecretion in male non-obese diabetic (NOD) mice in a SS-like model. In this study, we investigated the effect of blueberry 'stem' water extract (BStEx) on lacrimal hyposecretion in NOD mice. MATERIALS AND METHODS: Male NOD mice were fed 1% BStEx or control (AIN-93G) for 2, 4, or 6 weeks from 4 weeks of age. Pilocarpine-induced tear secretion was measured using a phenol red-impregnated thread. The lacrimal glands were histologically evaluated by HE staining. Inflammatory cytokine levels in the lacrimal glands were measured using ELISA. Immunostaining was performed to examine aquaporin 5 (AQP5) localization. The expression levels of autophagy-related proteins, AQP5, and phosphorylated AMPK were measured using western blotting. RESULTS: After feeding BStEx to mice for 4 or 6 weeks, tear volume was observed to have increased in the BStEx group compared with that in the control group. There were no significant differences in inflammatory cell infiltration, autophagy-related protein expression, or the localization and expression of AQP5 in the lacrimal glands between the two groups. In contrast, AMPK phosphorylation increased in the BStEx group. CONCLUSION: BStEx prevented lacrimal hyposecretion in the SS-like model of male NOD mice, probably by opening tight junctions via the activation of AMPK in lacrimal acinar cells.
Asunto(s)
Arándanos Azules (Planta) , Diabetes Mellitus Experimental , Aparato Lagrimal , Síndrome de Sjögren , Masculino , Ratones , Animales , Aparato Lagrimal/metabolismo , Aparato Lagrimal/patología , Ratones Endogámicos NOD , Proteínas Quinasas Activadas por AMP/metabolismo , Diabetes Mellitus Experimental/metabolismo , Calidad de Vida , Extractos Vegetales/farmacología , Modelos Animales de EnfermedadRESUMEN
Although chronic cardiac dysfunction is known to progressively exacerbate renal injury, a condition known as type 2 cardiorenal syndrome (CRS), the mechanism responsible is largely unknown. The present study was undertaken to clarify the mechanism of renal injury in rats with both unilateral nephrectomy (NX) and surgically induced myocardial infarction (MI), corresponding to a model of type 2 CRS. Compared with a control group, rats with both MI and NX (MI+NX) exhibited progressive proteinuria during the experimental period (34 wk after MI surgery), whereas proteinuria was not observed in rats with MI alone and was moderate in rats with NX alone. The proteinuria in rats with MI+NX was associated with renal lesions such as glomerulosclerosis and infiltration of mononuclear cells and upregulation of the renal proinflammatory and -fibrotic cytokine and angiotensin II type 1a receptor (AT1aR) genes. In contrast, plasma renin activity was lowered in rats with MI+NX. Immunohistochemistry revealed that the increased AT1R protein was present mainly in renal interstitial mononuclear cells. Olmesartan medoxomil, an AT1R blocker, markedly reduced the proteinuria and infiltration of mononuclear cells, whereas spironolactone, a mineralocorticoid receptor blocker, did not. The present findings demonstrate the pathogenetic role of renal interstitial AT1R signaling in a model of type 2 CRS, providing evidence that AT1R blockade can be a useful therapeutic option for this syndrome.
Asunto(s)
Síndrome Cardiorrenal/metabolismo , Riñón/metabolismo , Receptor de Angiotensina Tipo 1/metabolismo , Bloqueadores del Receptor Tipo 1 de Angiotensina II/farmacología , Animales , Expresión Génica , Imidazoles/farmacología , Riñón/efectos de los fármacos , Riñón/patología , Masculino , Antagonistas de Receptores de Mineralocorticoides/farmacología , Infarto del Miocardio , Nefrectomía , Olmesartán Medoxomilo , Proteinuria , Ratas , Receptor de Angiotensina Tipo 1/genética , Renina/sangre , Renina/metabolismo , Espironolactona/farmacología , Tetrazoles/farmacologíaRESUMEN
BACKGROUND: DBA/2FG-pcy (pcy) mice harbor a homozygous Nphp3 missense mutation and develop nephronophthisis with renal interstitial fibrosis. Previous studies have shown that aberrant oxygen homeostasis contributes to the renal pathology in pcy mice, but the underlying molecular mechanism remains largely unknown. METHODS: pcy mice and a control strain, DBA/2N (DBA) mice, were used. Renal levels of 62 mRNAs involved in oxygen homeostasis were investigated by real-time PCR, and the resulting data were used for extraction of pathological pathways. On the basis of the genes found to be upregulated and pathway analysis, further studies were performed using immunoblotting, immunohistochemistry, and pharmacological intervention. RESULTS: In comparison with DBA mice, the levels of 18 mRNAs were altered by >2-fold in pcy mice. Pathway analysis extracted molecular pathways related to oxidative stress, inflammation, and cell adhesion. As the levels of mRNAs relevant to the NADPH oxidase 2 (NOX2) pathway were prominently (4 genes >5-fold) increased in pcy mice, we further analyzed the molecules related to this pathway. A time course study suggested that the pathway was gradually activated in pcy mice from at least 5 weeks of age. Immunohistochemistry study revealed that NOX2 protein was colocalized with a macrophage marker protein in the renal interstitium. Moreover, treatment of pcy mice with apocynin, an inhibitor of the NOX2 pathway, ameliorated the renal fibrosis. CONCLUSION: Our findings suggest that the activation of the NOX2 pathway, possibly mediated by macrophage infiltration, plays a pivotal role in progressive renal fibrosis in pcy mice.
Asunto(s)
NADPH Oxidasa 2/metabolismo , Enfermedades Renales Poliquísticas , Animales , Fibrosis , Ratones , Ratones Endogámicos DBA , Modelos Teóricos , NADPH Oxidasa 2/genética , NADPH Oxidasas/genética , NADPH Oxidasas/metabolismo , Oxígeno/metabolismo , Enfermedades Renales Poliquísticas/genética , ARN Mensajero/genética , Regulación hacia ArribaRESUMEN
A 5-y-old female bottlenose dolphin (Tursiops truncatus) from an aquarium in Japan had clinical signs of anorexia, vomiting, and bradykinesia. Enrofloxacin and lactated Ringer solution were administered for treatment of bacterial infection and for rehydration. Elevations of creatine kinase and aspartate aminotransferase activities were detected on day 4 of treatment, indicating that rhabdomyolysis had developed on day 3. On day 5, serum creatinine and urea concentrations increased and remained high throughout the remaining treatment; the dolphin died on day 16. Postmortem examination revealed massive necrosis of the longissimus dorsi muscles. Histologic examination revealed extensive necrosis of skeletal myofibers, multifocal renal tubular necrosis with intratubular casts and crystals, and suppurative bronchopneumonia. The renal casts labeled positively with anti-myoglobin antibody; expression of aquaporin-1 was decreased in renal tubules compared to normal kidney tissue. To our knowledge, this description of clinicopathologic findings of rhabdomyolysis leading to acute kidney injury with concomitant crystalline nephropathy has not been reported previously in a bottlenose dolphin.
Asunto(s)
Lesión Renal Aguda , Delfín Mular , Nefrosis , Rabdomiólisis , Lesión Renal Aguda/veterinaria , Animales , Femenino , Necrosis/veterinaria , Nefrosis/complicaciones , Nefrosis/veterinaria , Rabdomiólisis/complicaciones , Rabdomiólisis/diagnóstico , Rabdomiólisis/veterinariaRESUMEN
Although several studies have shown that release of water channel proteins, aquaporin 1 (AQP1) and AQP2 in urinary extracellular vesicles (uEV-AQP1 and -AQP2), were altered in experimental kidney injury models, their release in human chronic kidney disease (CKD) has been largely unexplored. The aim of the present study was to clarify whether the release of uEV-AQP1 and -AQP2 is altered in patients with CKD. Urine samples were collected from 15 healthy volunteers (normal group) and 62 CKD patients who were categorized into six glomerular filtration rate (GFR) categories (G1, G2, G3a, G3b, G4, and G5) in between 2005 and 2016 at Miyazaki Prefectural Miyazaki Hospital, Japan. uEV-proteins were evaluated by immunoblot analysis. The release of AQP1 and AQP2 were significantly decreased in patients with both CKD G4 and G5, in comparison with the normal group. The area under the receiver operating characteristic (ROC) curve (AUC) values for AQP1 and AQP2 in patients with CKD G4 and G5 were 0.926 and 0.881, respectively. On the other hand, the AUC values in patients with CKD G1-G3 were 0.512 for AQP1 and 0.680 for AQP2. Multiple logistic regression analysis showed that AQP1 and AQP2 in combination were useful for detecting CKD G4 and G5, with a higher AUC value of 0.945. These results suggest that the release of uEV-AQP1 and -AQP2 was decreased in patients with CKD G4 and G5, and these proteins might be helpful to detect advanced CKD.
Asunto(s)
Acuaporina 1/orina , Acuaporina 2/orina , Vesículas Extracelulares/metabolismo , Tasa de Filtración Glomerular/fisiología , Insuficiencia Renal Crónica/diagnóstico , Insuficiencia Renal Crónica/orina , Adolescente , Adulto , Anciano , Biomarcadores/orina , Progresión de la Enfermedad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
Overexpression of heat shock protein 70 kDa (HSP70) is known to confer cellular protection against ischemia-reperfusion (I/R) injury. Radicicol, a HSP90 inhibitor, has been reported to induce the expression of HSP70 protein. Here we studied whether radicicol attenuated renal I/R injury in vivo. Treatment of mice with radicicol ameliorated renal I/R injury and increased renal HSP70 mRNA and protein. Administration of radicicol with quercetin, an inhibitor of HSP70 induction, eliminated the renoprotective effect of radicicol. Our results suggest that the up-regulation of renal HSP70 protein by radicicol leads to a novel drug therapy against renal I/R injury.
Asunto(s)
Riñón/efectos de los fármacos , Macrólidos/farmacología , Daño por Reperfusión/prevención & control , Animales , Proteínas HSP70 de Choque Térmico/efectos de los fármacos , Proteínas HSP70 de Choque Térmico/genética , Proteínas HSP70 de Choque Térmico/metabolismo , Proteínas HSP90 de Choque Térmico/antagonistas & inhibidores , Riñón/patología , Masculino , Ratones , Quercetina/farmacología , ARN Mensajero/efectos de los fármacos , ARN Mensajero/metabolismo , Regulación hacia Arriba/efectos de los fármacosRESUMEN
Urinary exosomes, secreted into urine from renal epithelial cells, are known to contain many types of renal functional membrane proteins. Here, we studied whether renal ischemia-reperfusion (I/R) affects urinary exosomal aquaporin-1 (AQP1) excretion in rats subjected to renal I/R and patients who underwent renal transplantation. Immunoblotting studies demonstrated reduction of the urinary exosomal AQP1 level even at 6 h after renal I/R, and the level continued to be low over 96 h after I/R. Renal AQP1 mRNA and protein analyses revealed that the decreased excretion of urinary exosomal AQP1 is associated with renal AQP1 protein retention in the early phase and with a decreased expression level of renal AQP1 in the later phase of renal I/R injury. Decreased abundance of urinary exosomal AQP1 in a recipient patient was also observed at 48 h after renal allograft transplantation. No significant decrease in urinary exosomal AQP1 was observed in a rat model of nephropathy or in patients with proteinuria. Our studies suggest that the renal AQP1 expression level is possibly controlled by its urinary exosomal excretion and indicate that urinary exosomal AQP1 is a novel urinary biomarker for renal I/R injury.
Asunto(s)
Acuaporina 1/orina , Riñón/metabolismo , Proteinuria/orina , Daño por Reperfusión/orina , Animales , Antimetabolitos Antineoplásicos , Síndrome de Chediak-Higashi/orina , Humanos , Inmunohistoquímica , Trasplante de Riñón , Masculino , Puromicina , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Daño por Reperfusión/sangreRESUMEN
Aquaporin-1 (AQP1) and AQP2 are important proteins involved in the regulation of renal water handling. Both AQPs have been found in urinary extracellular vesicles (uEVs) (uEV-AQP1 and -AQP2). Cisplatin, an antineoplastic agent, is known to down-regulate renal AQP1 and AQP2. However, the effect of cisplatin on the release of uEV-AQP1 and -AQP2 is largely unknown. In this study, we examined whether treatment of rats with cisplatin affected the release of uEV-AQP1 and -AQP2. Blood tests indicated that renal function was little altered at 24 h after cisplatin treatment but thereafter decreased dramatically at all of the other time points examined. Release of uEV-AQP1 was slightly increased at 24 h and decreased at 168 h. On the other hand, release of uEV-AQP2 was decreased dramatically at 24 h, and the decrease was maintained during the experimental period. These data suggest that uEV-AQP2 can be used to detect early renal impairment due to cisplatin. Furthermore, a combination of uEV-AQP2 and -AQP1 may be useful for estimation of cisplatin-induced renal injury in a stage-dependent manner.