Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 10 de 10
Filtrar
1.
Kidney Int ; 86(1): 127-38, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24522493

RESUMEN

X-linked nephrogenic diabetes insipidus (X-NDI) is a disease caused by inactivating mutations of the vasopressin (AVP) type 2 receptor (V2R) gene. Loss of V2R function prevents plasma membrane expression of the AQP2 water channel in the kidney collecting duct cells and impairs the kidney concentration ability. In an attempt to develop strategies to bypass V2R signaling in X-NDI, we evaluated the effects of secretin and fluvastatin, either alone or in combination, on kidney function in a mouse model of X-NDI. The secretin receptor was found to be functionally expressed in the kidney collecting duct cells. Based on this, X-NDI mice were infused with secretin for 14 days but urinary parameters were not altered by the infusion. Interestingly, secretin significantly increased AQP2 levels in the collecting duct but the protein primarily accumulated in the cytosol. Since we previously reported that fluvastatin treatment increased AQP2 plasma membrane expression in wild-type mice, secretin-infused X-NDI mice received a single injection of fluvastatin. Interestingly, urine production by X-NDI mice treated with secretin plus fluvastatin was reduced by nearly 90% and the urine osmolality was doubled. Immunostaining showed that secretin increased intracellular stores of AQP2 and the addition of fluvastatin promoted AQP2 trafficking to the plasma membrane. Taken together, these findings open new perspectives for the pharmacological treatment of X-NDI.


Asunto(s)
Diabetes Insípida Nefrogénica/complicaciones , Diabetes Insípida Nefrogénica/tratamiento farmacológico , Ácidos Grasos Monoinsaturados/administración & dosificación , Indoles/administración & dosificación , Poliuria/tratamiento farmacológico , Poliuria/etiología , Secretina/administración & dosificación , Animales , Acuaporina 2/metabolismo , AMP Cíclico/metabolismo , Diabetes Insípida Nefrogénica/fisiopatología , Modelos Animales de Enfermedad , Exocitosis , Fluvastatina , Expresión Génica , Humanos , Túbulos Renales Colectores/efectos de los fármacos , Túbulos Renales Colectores/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Mutantes , Poliuria/fisiopatología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Receptores de la Hormona Gastrointestinal/genética , Receptores de la Hormona Gastrointestinal/metabolismo , Receptores de Vasopresinas/deficiencia , Receptores de Vasopresinas/genética
2.
Cell Physiol Biochem ; 33(3): 731-46, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24662389

RESUMEN

BACKGROUND/AIMS: Extracellular GTP is able to modulate some specific functions in neuron, glia and muscle cell models as it has been demonstrated over the last two decades. In fact, extracellular GTP binds its specific plasma membrane binding sites and induces signal transduction via [Ca(2+)]i increase. We demonstrate, for the first time, that extracellular GTP is able to modulate cell swelling in M1-CCD cortical collecting duct epithelial cells via upregulation of aquaporin 5 (AQP5) expression. METHODS: We used videoimaging, immunocitochemistry, flow cytometry, confocal techniques, Western blotting and RT-PCR for protein and gene expression analysis, respectively. RESULTS: We demonstrate that AQP5 mRNA is up-regulated 7 h after the GTP exposure in the cell culture medium, and its protein level is increased after 12-24 h. We show that AQP5 is targeted to the plasma membrane of M1-CCD cells, where it facilitates cell swelling, and that the GTP-dependent AQP5 up-regulation occurs via [Ca(2+)]i increase. Indeed, GTP induces both oscillating and transient [Ca(2+)]i increase, and specifically the oscillating kinetic appears to be responsible for blocking cell cycle in the S-phase while the [Ca(2+)]i influx, with whatever kinetic, seems to be responsible for inducing AQP5 expression. CONCLUSION: The role of GTP as a regulator of AQP5-mediated water transport in renal cells is of great importance in the physiology of renal epithelia, due to its possible physiopathological implications. GTP-dependent AQP5 expression could act as osmosensor. In addition, the data presented here suggest that GTP might play the same role in other tissues where rapid water transport is required for cell volume regulation and maintenance of the homeostasis.


Asunto(s)
Acuaporina 5/biosíntesis , Membrana Celular/metabolismo , Células Epiteliales/metabolismo , Guanosina Trifosfato/farmacología , Túbulos Renales Colectores/metabolismo , Regulación hacia Arriba/efectos de los fármacos , Animales , Señalización del Calcio/efectos de los fármacos , Línea Celular , Células Epiteliales/citología , Túbulos Renales Colectores/citología , Ratones
3.
Cell Physiol Biochem ; 32(7): 184-99, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24429825

RESUMEN

BACKGROUND: We recently reported that aquaporin 5 (AQP5), a water channel never identified in the kidney before, co-localizes with pendrin at the apical membrane of type-B intercalated cells in the kidney cortex. Since co-expression of AQP5 and pendrin in the apical membrane domain is a common feature of several other epithelia such as cochlear and bronchial epithelial cells, we evaluated here whether this strict membrane association may reflect a co-regulation of the two proteins. To investigate this possibility, we analyzed AQP5 and pendrin expression and trafficking in mice under chronic K(+) depletion, a condition that results in an increased ability of renal tubule to reabsorb bicarbonate, often leads to metabolic alkalosis and is known to strongly reduce pendrin expression. METHODS: Mice were housed in metabolic cages and pair-fed with either a standard laboratory chow or a K(+)-deficient diet. AQP5 abundance was assessed by western blot in whole kidney homogenates and AQP5 and pendrin were localized by confocal microscopy in kidney sections from those mice. In addition, the short-term effect of changes in external pH on pendrin trafficking was evaluated by fluorescence resonance energy transfer (FRET) in MDCK cells, and the functional activity of pendrin was tested in the presence and absence of AQP5 in HEK 293 Phoenix cells. RESULTS: Chronic K(+) depletion caused a strong reduction in pendrin and AQP5 expression. Moreover, both proteins shifted from the apical cell membrane to an intracellular compartment. An acute pH shift from 7.4 to 7.0 caused pendrin internalization from the plasma membrane. Conversely, a pH shift from 7.4 to 7.8 caused a significant increase in the cell surface expression of pendrin. Finally, pendrin ion transport activity was not affected by co-expression with AQP5. CONCLUSIONS: The co-regulation of pendrin and AQP5 membrane expression under chronic K(+)-deficiency indicates that these two molecules could cooperate as an osmosensor to rapidly detect and respond to alterations in luminal fluid osmolality.


Asunto(s)
Proteínas de Transporte de Anión/biosíntesis , Acuaporina 5/biosíntesis , Corteza Renal/metabolismo , Potasio/metabolismo , Animales , Proteínas de Transporte de Anión/metabolismo , Acuaporina 5/metabolismo , Bicarbonatos/metabolismo , Membrana Celular/metabolismo , Células Epiteliales/metabolismo , Regulación de la Expresión Génica , Células HEK293 , Humanos , Transporte Iónico/genética , Corteza Renal/citología , Ratones , Microscopía Inmunoelectrónica , Transportadores de Sulfato
4.
Biol Cell ; 104(11): 658-76, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22708623

RESUMEN

BACKGROUND INFORMATION: The renal Na(+) -K(+) -2Cl(-) co-transporter (NKCC2) is expressed in kidney thick ascending limb cells, where it mediates NaCl re-absorption regulating body salt levels and blood pressure. RESULTS: In this study, we used a well-characterised NKCC2 construct (c-NKCC2) to identify NKCC2-interacting proteins by an antibody shift assay coupled with blue native/SDS-PAGE and mass spectrometry. Among the interacting proteins, we identified moesin, a protein belonging to ezrin, eadixin and moesin family. Co-immunoprecipitation experiments confirmed that c-NKCC2 interacts with the N-terminal domain of moesin in LLC-PK1 cells. Moreover, c-NKCC2 accumulates in intracellular and sub-apical vesicles in cells transfected with a moesin dominant negative green fluorescent protien (GFP)-tagged construct. In addition, moesin knock-down by short interfering RNA decreases by about 50% c-NKCC2 surface expression. Specifically, endocytosis and exocytosis assays showed that moesin knock-down does not affect c-NKCC2 internalisation but strongly reduces exocytosis of the co-transporter. CONCLUSIONS: Our data clearly demonstrate that moesin plays a critical role in apical membrane insertion of NKCC2, suggesting a possible involvement of moesin in regulation of Na(+) and Cl(-) absorption in the kidney.


Asunto(s)
Proteínas de Microfilamentos/metabolismo , Simportadores de Cloruro de Sodio-Potasio/metabolismo , Animales , Membrana Celular/metabolismo , Movimiento Celular , Células Cultivadas , Endocitosis/fisiología , Células Epiteliales/metabolismo , Exocitosis/fisiología , Técnicas de Silenciamiento del Gen , Riñón/metabolismo , Proteínas de Microfilamentos/genética , Unión Proteica , Transporte de Proteínas/fisiología , Ratas , Simportadores de Cloruro de Sodio-Potasio/inmunología , Miembro 1 de la Familia de Transportadores de Soluto 12 , Porcinos/metabolismo
5.
Pflugers Arch ; 462(5): 753-66, 2011 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-21858457

RESUMEN

X-linked nephrogenic diabetes insipidus (XNDI), a severe pathological condition characterized by greatly impaired urine-concentrating ability of the kidney, is caused by inactivating mutations in the V2 vasopressin receptor (V2R) gene. The lack of functional V2Rs prevents vasopressin-induced shuttling of aquaporin-2 (AQP2) water channels to the apical plasma membrane of kidney collecting duct principal cells, thus promoting water reabsorption from urine to the interstitium. At present, no specific pharmacological therapy exists for the treatment of XNDI. We have previously reported that the cholesterol-lowering drug lovastatin increases AQP2 membrane expression in renal cells in vitro. Here we report the novel finding that fluvastatin, another member of the statins family, greatly increases kidney water reabsorption in vivo in mice in a vasopressin-independent fashion. Consistent with this observation, fluvastatin is able to increase AQP2 membrane expression in the collecting duct of treated mice. Additional in vivo and in vitro experiments indicate that these effects of fluvastatin are most likely caused by fluvastatin-dependent changes in the prenylation status of key proteins regulating AQP2 trafficking in collecting duct cells. We identified members of the Rho and Rab families of proteins as possible candidates whose reduced prenylation might result in the accumulation of AQP2 at the plasma membrane. In conclusion, these results strongly suggest that fluvastatin, or other drugs of the statin family, may prove useful in the therapy of XNDI.


Asunto(s)
Acuaporina 2/genética , Diabetes Insípida Nefrogénica/fisiopatología , Ácidos Grasos Monoinsaturados/farmacología , Indoles/farmacología , Túbulos Renales Colectores/metabolismo , Animales , Acuaporina 2/biosíntesis , Membrana Celular/metabolismo , Diabetes Insípida Nefrogénica/tratamiento farmacológico , Diabetes Insípida Nefrogénica/genética , Ácidos Grasos Monoinsaturados/uso terapéutico , Fluvastatina , Indoles/uso terapéutico , Túbulos Renales Colectores/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos C57BL , Prenilación/efectos de los fármacos , Proteínas de Unión al GTP rab/efectos de los fármacos , Proteínas de Unión al GTP rab/metabolismo , Quinasas Asociadas a rho/efectos de los fármacos , Quinasas Asociadas a rho/metabolismo
6.
Cell Physiol Biochem ; 28(4): 683-92, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-22178880

RESUMEN

We screened human kidney-derived multipotent CD133+/CD24+ ARPCs for the possible expression of all 13 aquaporin isoforms cloned in humans. Interestingly, we found that ARPCs expressed both AQP5 mRNA and mature protein. This novel finding prompted us to investigate the presence of AQP5 in situ in kidney. We report here the novel finding that AQP5 is expressed in human, rat and mouse kidney at the apical membrane of type-B intercalated cells. AQP5 is expressed in the renal cortex and completely absent from the medulla. Immunocytochemical analysis using segment- and cell type-specific markers unambiguously indicated that AQP5 is expressed throughout the collecting system at the apical membrane of type-B intercalated cells, where it co-localizes with pendrin. No basolateral AQPs were detected in type-B intercalated cells, suggesting that AQP5 is unlikely to be involved in the net trans-epithelial water reabsorption occurring in the distal tubule. An intriguing hypothesis is that AQP5 may serve an osmosensor for the composition of the fluid coming from the thick ascending limb. Future studies will unravel the physiological role of AQP5 in the kidney.


Asunto(s)
Túbulos Renales Colectores/metabolismo , Antígeno AC133 , Animales , Antígenos CD/metabolismo , Acuaporina 5/genética , Acuaporina 5/metabolismo , Células Cultivadas , Glicoproteínas/metabolismo , Humanos , Inmunohistoquímica , Túbulos Renales Colectores/citología , Túbulos Renales Colectores/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Péptidos/metabolismo , Ratas , Ratas Wistar , Células Madre/metabolismo
7.
Comp Immunol Microbiol Infect Dis ; 75: 101624, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33609989

RESUMEN

Study's aims were to characterize subclinical bacteriuria (SB) and sporadic bacterial cystitis (SBC) in dogs with spontaneous hypercortisolism (HC). Prospective cross-sectional design divided patients as newly diagnosed (n = 27), poorly controlled (n  = 21), well controlled (n  = 34), and controls (n  = 19). Urine culture positive results were identified by MALDI-TOF and submitted to antibiogram. Escherichia coli was the most common microorganism (36%). The majority of positive cultures in HC were SB (12.2%). All 4.1% SBC cases were in well controlled HC cases. Bacteriuria correlated with low urine specific gravity and low lymphocyte count. HC degree of control correlated with leukocyturia. SB/SBC cases were treated based in antimicrobial susceptibility leading to microbiological cure in 75% of HC cases. Persistent infections occurred only in SB cases, all by E. coli which became more resistant. SB/SBC prevalence in canine HC is actually lower. Further evidence for current ISCAID guideline contraindication for SB treatment due to HC were provided.


Asunto(s)
Bacteriuria , Síndrome de Cushing , Cistitis , Enfermedades de los Perros , Infecciones Urinarias , Animales , Bacteriuria/epidemiología , Bacteriuria/veterinaria , Estudios Transversales , Síndrome de Cushing/veterinaria , Cistitis/epidemiología , Cistitis/veterinaria , Enfermedades de los Perros/tratamiento farmacológico , Enfermedades de los Perros/epidemiología , Perros , Escherichia coli , Estudios Prospectivos , Infecciones Urinarias/veterinaria
8.
Semin Pediatr Surg ; 30(3): 151051, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-34172209

RESUMEN

Teamwork is one of the most important trend in modern medicine. Airway team were created in many places to respond in a multidisciplinary and coordinated way to challenging clinical problems which were beyond the possibility of an individual management. In this chapter, we illustrate the historical steps leading to the development of an airway team in a pediatric referral hospital, describe the present teamwork activity defining the key points for the creation of a team and discussing different organization models; finally we delineate possible future directions for the airway teams in the globalized world.


Asunto(s)
Grupo de Atención al Paciente , Derivación y Consulta , Niño , Humanos
9.
Front Pediatr ; 6: 236, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30246003

RESUMEN

During general anesthesia, while muscle relaxants, latex and antibiotics are normally considered as very common causes of anaphylactic reactions, there are no documented cases of anaphylaxis due to inhalational agents. We report the case of a 6-year-old child scheduled for adenotonsillectomy who had an anaphylactic shock reaction due to Sevoflurane. Several allergic tests were performed to detect the trigger. Drugs used during operation were tested on both patient and three matched controls. While controls were negative, the patient displayed a positive reaction to Sevoflurane. To our knowledge, this is the first published report describing an allergic reaction caused by a volatile anesthetic.

10.
J Cell Sci ; 121(Pt 12): 2097-106, 2008 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-18505797

RESUMEN

Vasopressin regulates the fusion of the water channel aquaporin 2 (AQP2) to the apical membrane of the renal collecting-duct principal cells and several lines of evidence indicate that SNARE proteins mediate this process. In this work MCD4 renal cells were used to investigate the functional role of a set of Q- and R-SNAREs, together with that of Munc18b as a negative regulator of the formation of the SNARE complex. Both VAMP2 and VAMP3 were associated with immunoisolated AQP2 vesicles, whereas syntaxin 3 (Stx3), SNAP23 and Munc18 were associated with the apical plasma membrane. Co-immunoprecipitation experiments indicated that Stx3 forms complexes with VAMP2, VAMP3, SNAP23 and Munc18b. Protein knockdown coupled to apical surface biotinylation demonstrated that reduced levels of the R-SNAREs VAMP2 and VAMP3, and the Q-SNAREs Stx3 and SNAP23 strongly inhibited AQP2 fusion at the apical membrane. In addition, knockdown of Munc18b promoted a sevenfold increase of AQP2 fused at the plasma membrane without forskolin stimulation. Taken together these findings propose VAMP2, VAMP3, Stx3 and SNAP23 as the complementary set of SNAREs responsible for AQP2-vesicle fusion into the apical membrane, and Munc18b as a negative regulator of SNARE-complex formation in renal collecting-duct principal cells.


Asunto(s)
Túbulos Renales Colectores/fisiología , Proteínas Munc18/metabolismo , Proteínas Q-SNARE/metabolismo , Proteína 2 de Membrana Asociada a Vesículas/metabolismo , Proteína 3 de Membrana Asociada a Vesículas/metabolismo , Animales , Acuaporina 2/antagonistas & inhibidores , Acuaporina 2/genética , Acuaporina 2/metabolismo , Línea Celular , Polaridad Celular , Perros , Exocitosis , Retroalimentación Fisiológica , Fusión de Membrana , Proteínas Munc18/genética , Especificidad de Órganos , Transporte de Proteínas/genética , Proteínas Q-SNARE/antagonistas & inhibidores , Proteínas Q-SNARE/genética , ARN Interferente Pequeño , Vasopresinas/metabolismo , Proteína 2 de Membrana Asociada a Vesículas/genética , Proteína 3 de Membrana Asociada a Vesículas/genética
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA