Physiological Functions and Regulation of the Na+/H+ Exchanger [NHE1] in Renal Tubule Epithelial Cells

The sodium-hydrogen exchanger isoform-1 [NHE1] is a ubiquitously expressed plasma membrane protein that plays a central role in intracellular pH and cell volume homeostasis by catalyzing an electroneutral exchange of extracellular sodium and intracellular hydrogen. Outside of this important physiological function, the NHE1 cytosolic tail domain acts as a molecular scaffold regulating cell survival and actin cytoskeleton organization through NHE1-dependent signaling proteins. NHE1 plays main roles in response to physiological stress conditions which in addition to cell shrinkage and acidification, include hypoxia and mechanical stimuli, such as cell stretch. NHE1-mediated modulation of programmed cell death results from the exchanger-mediated changes in pHi, cell volume, and/or [Na+]I; and, it has recently become known that regulation of cellular signaling pathways are involved as well. This review focuses on NHE1 functions and regulations. We describe evidence showing how these structural actions integrate with ion translocation in regulating renal tubule epithelial cell survival.Fil: Garramuño, Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; ArgentinaFil: Bocanegra, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Gil Lorenzo, Andrea Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Costantino, Valeria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentin

Molecular mechanisms of hypertensive nephropathy: Renoprotective effect of losartan through hsp70

Hypertensive nephrosclerosis is the second most common cause of end-stage renal disease after diabetes. For years, hypertensive kidney disease has been focused on the afferent arterioles and glomeruli damage and the involvement of the renin angiotensin system (RAS). Nonetheless, in recent years, novel evidence has demonstrated that persistent high blood pressure injures tubular cells, leading to epithelial–mesenchymal transition (EMT) and tubulointerstitial fibrosis. Injury primarily determined at the glomerular level by hypertension causes changes in post-glomerular peritubular capillaries that in turn induce endothelial damage and hypoxia. Microvasculature dysfunction, by inducing hypoxic environment, triggers inflammation, EMT with epithelial cells dedifferentiation and fibrosis. Hypertensive kidney disease also includes podocyte effacement and loss, leading to disruption of the filtration barrier. This review highlights the molecular mechanisms and histologic aspects involved in the pathophysiology of hypertensive kidney disease incorporating knowledge about EMT and tubulointerstitial fibrosis. The role of the Hsp70 chaperone on the angiotensin II–induced EMT after angiotensin II type 1 receptor (AT1R) blockage, as a possible molecular target for therapeutic strategy against hypertensive renal damage is discussed.Fil: Costantino, Valeria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Fisiología; ArgentinaFil: Gil Lorenzo, Andrea Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Fisiología; ArgentinaFil: Bocanegra, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Vallés, Patricia G.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Fisiología; Argentin

Heat shock protein 70 and CHIP promote Nox4 ubiquitination and degradation within the losartan antioxidative effect in proximal tubule cells

Background: Angiotensin II/Angiotensin II type 1 receptor (AT1R) effects are dependent on ROS production stimulated by NADPH oxidase activation. Hsp70 regulates a diverse set of signaling pathways through their interactions with proteins. CHIP is a E3 ubiquitin ligase that targets proteins for polyubiquitination and degradation. Aim: We study whether Hsp70/CHIP contribute to the negative regulation of Nox4 after AT1R blockage. Methods/Results: Primary culture of proximal tubule epithelial cells (PTCs) from SHR and WKY were stimulated with Angiotensin II (AII) or treated with Losartan (L) or Losartan plus Angiotensin II (L+AII). Losartan decreased AT1R and Nox4 while enhancing caveolin-1 and Hsp70 protein expression in SHR PTCs. Immunoprecipitation and immunofluorescence proved interaction and colocalization of increased Hsp70/CHIP with decreased Nox4 in SHR PTCs (L) vs (All). Hsp72 knockdown resulted in enhanced Nox4 protein levels, NADPH oxidase activity and ROS generation in (L+AII) revealing that Losartan was unable to abrogate AII effects on Nox4 expression and oxidative activity. Moreover, MG132 exposed PTCs (L) demostrated blocked ubiquitinated Nox4 degradation and increased colocalization of Nox4/Ubiquitin by inmunofluorescence. Conversely, Hsp72 depletion reduced Nox4/Ubiquitin colocalization causing Nox4 upregulation due to proteosomal degradation inhibition, although Losartan treatment. Conclusion: Our study demonstrates that Hsp70 and CHIP mediates the ubiquitination and proteasomal degradation of Nox4 as part ofthe antioxidative effect of Losartan in SHR.Fil: Costantino, Valeria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Gil Lorenzo, Andrea Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Lopez Appiolaza, Carlos Martìn. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Cacciamani, Valeria. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Cátedra de Fisiología Patológica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Benardon, María Eugenia. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Cátedra de Fisiología Patológica; ArgentinaFil: Bocanegra, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Garramuño, Patricia. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Cátedra de Fisiología Patológica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentin

Generación de valor en el desarrollo de un negocio especializado en la comercialización de paneles solares para personas naturales localizadas en el distrito de La Joya-Arequipa entre el 2014-2019

Este trabajo de investigación tiene como objetivo estimar la generación de valor financiero en la creación de un negocio de comercialización de paneles solares para personas naturales en el distrito de La Joya del departamento de Arequipa y como objetivos específicos establecer la rentabilidad y viabilidad que genera la comercialización de paneles solares para personas naturales mediante el cálculo de indicadores financieros y de este modo determinar la estrategia de negocio que se debe utilizar para aportar generación de valor en este tipo de negocio dentro de un lugar que no es céntrico con respecto a la ciudad de Arequipa. El problema se abordó mediante una investigación de tipo descriptiva correlacional para medir el nivel de relación que existe entre la rentabilidad del negocio y la comercialización de paneles solares donde se busca evidenciar que tan representativa es la generación de valor de este negocio. Esta investigación pondrá en evidencia si esta rentabilidad es efectiva por los costos del producto, ya sea que el producto principal sea importado a un precio bajo o se fabrica en el país de comercialización y tiempos para la obtención del producto final. Así como, la necesidad de los posibles usuarios para con el bien. Cabe mencionar que se recopilo información tanto de los comerciantes actuales y los consumidores y posibles consumidores de paneles.This research work aims to estimate the generation of financial value in the creation of a commercialization business of solar panels for natural persons in the district of La Joya of the department of Arequipa and as specific objectives to establish the profitability and viability that commercialization generates of solar panels for natural persons through the calculation of financial indicators and in this way determine the business strategy that should be used to provide value generation in this type of business within a place that is not central to the city of Arequipa . The problem was approached through a correlational descriptive investigation to measure the level of relationship between the profitability of the business and the commercialization of solar panels where it is sought to show how representative the generation of value of this business is. This investigation will show whether this profitability is effective due to the costs of the product, whether the main product is imported at a low price or manufactured in the country of commercialization and times for obtaining the final product. As well as, the need for potential users for good. It is worth mentioning that information was collected from both current merchants and consumers and potential panel consumers.Trabajo de investigaciónCampus Lima Centr

Granulomatosis with Polyangeitis. Rapidly progressive necrotizing glomerulonephritis in a pediatric patient

Granulomatosis with polyangitis (GPA) is associated with a broad range of clinical manifestations including renal disease. It is a systemic vasculitis that is rarely encountered in children. We present a 14-year-old girl who suffer for pharyngitis one week before. She was admitted for macroscopic hematuria and oliguria, under the possibility of nephritic syndrome.Renal failure with rapidly progressive glomerulonephritis ocurred within 24hour. Immunologic tests showed the presence of type-C anti-neutrophil cytoplasmic antibodies(c-ANCA with antiproteinase 3 specificity) and renal biopsy revealed pauci immune crescentic focal necrotizing glomerulonephritis. Treatment including methylprednisolone and cyclophosphamide intravenous pulses allowed renal recovery after 3 weeks. The clinical, haematological and biochemical parameters improved substantially acheiving remission. Granulomatosis with poliangeitis, although rare in children, should be considered in the above clinical scenario. This case underlines that knowledge of renal histology diagnosis and an early aggressive immunosuppressive therapy are essential for the management of these patientsFil: Luna, Maria. Hospital Humberto Notti. Departamento de Pediatría. Servicio de Nefrología; Argentina;Fil: Bocanegra, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina;Fil: Valles, Patricia G.. Hospital Humberto Notti. Departamento de Pediatría. Servicio de Nefrología; Argentina; Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Departamento de Patología; Argentina

Altered renal expression of Na + transporters and ROMK in protein-deprived rats

Potassium depletion has been associated with altered sodium reabsorption in tubule segments. We studied if the altered abundance of Na+ transporters and ROMK are associated with distal potassium secretion that contributes to the development of hypokalemia in protein-deprived rats. After weaning, Wistar rats were fed with a low-protein diet (8%, LP) for 14 days and then recovered with a normal-protein (NP) diet (24%, RP). An age-matched control group was fed with an NP diet (24%, NP). We showed hypokalemia, lower glomerular filtration rate and higher FEK+ in the LP group. Immunoblotting revealed that the type 3 Na+/H+ exchanger in the cortex was decreased in the LP group. However, the type 2 Na +-K+-2Cl- cotransporter was increased in the outer stripe of the outer medulla in the LP group. The abundance of the aldosterone-regulated Na+-Cl- cotransporter (NCC) and epithelial Na+ channel (ENaC) was higher in the LP group and was associated with higher plasma aldosterone level. ROMK protein levels were increased. Na+/K+-ATPase protein levels were the same in both groups. After the recovery period, the expression of Na+ transporters and ROMK returned to control values. We conclude that increased expression of NCC, ENaC subunits, and ROMK contributed to distal potassium secretion leading to enhanced potassium excretion, which may explain the hypokalemia resulting from LP feeding. A role of aldosterone may be suggested.Fil: Ruete, María Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Carrizo, Liliana C.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; ArgentinaFil: Bocanegra, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Vallés, Patricia G.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentin

The renal antioxidative effect of losartan involves heat shock protein 70 in proximal tubule cells

Angiotensin II exerts a cardinal role in the pathogenesis of hypertension and renal injury via action of angiotensin II type 1 (AT1) receptors. Local renin-angiotensin system (RAS) activity is essential for the mechanisms mediating pathophysiological functions. Proximal tubular angiotensinogen and tubular AT1 receptors are augmented by intrarenal angiotensin II. Caveolin 1 plays an important role as a regulatory molecule for the compartmentalization of redox signaling events through angiotensin II–induced NADPH oxidase activation in the kidney. A role for the renin-angiotensin system in the development and/or maintenance of hypertension has been demonstrated in spontaneously hypertensive rats (SHRs). Many effects of angiotensin II are dependent on the AT1 stimulation of reactive oxygen species (ROS) production by NADPH oxidase. Angiotensin II upregulation stimulates oxidative stress in proximal tubules from SHR. The NADPH oxidase 4 (Nox4) is abundantly expressed in kidney proximal tubule cells. Induction of the stress response includes synthesis of heat shock protein 70, a molecular chaperone that has a critical role in the recovery of cells from stress and in cytoprotection, guarding cells from subsequent insults. HSP70 chaperones function in part by driving the molecular triage decision, which determines whether proteins enter the productive folding pathway or result in client substrate ubiquitination and proteasomal degradation. This review examines regulation of losartan-mediated antioxidative stress responses by the chaperone HSP70 in proximal tubule cells of spontaneously hypertensive rats.Fil: Garramuño, Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Bocanegra, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Costantino, Valeria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Gil Lorenzo, Andrea Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Benardon, María Eugenia. Universidad Nacional de Cuyo; ArgentinaFil: Cacciamani, Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentin

Severely ill pediatric patients with Shiga toxin-associated hemolytic uremic syndrome (STEC-HUS) who suffered from multiple organ involvement in the early stage

Background: Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome (STEC-HUS) is the main cause of pediatric acute kidney injury (AKI) in Argentina. Endothelial injury is the trigger event in the microangiopathic process. The host inflammatory response to toxin and E. coli lipopolysaccharide (LPS) is involved in disease pathophysiology. Methods: This retrospective study describes pediatric STEC-HUS patients with multiorgan involvement at the initial phase of disease. A retrospective study of critically ill HUS patients with evidence of E. coli infection was conducted through a period of 15 years. Results: Forty-four patients 35.4 ± 4.1 months were admitted to the intensive care unit for 21 ± 2 days. Mechanical ventilation was required in 41 patients, early inotropic support in 37, and 28 developed septic shock. Forty-one patients required kidney replacement therapy for 12 ± 1 days. Forty-one patients showed neurological dysfunction. Dilated cardiomyopathy was demonstrated in 3 patients, left ventricular systolic dysfunction in 4, and hypertension in 17. Four patients had pulmonary hemorrhage, and acute respiratory distress syndrome in 2. Colectomy for transmural colonic necrosis was performed in 3 patients. Thirty-seven patients were treated with therapeutic plasma exchange, and 28 patients received methylprednisolone (10 mg/kg for 3 days). Of the surviving 32 patients, neurological sequelae were seen in 11 and chronic kidney failure in 5. Conclusions: Severe clinical outcome at onset suggests an amplified inflammatory response after exposure to Shiga toxin and/or E. coli LPS. STEC-HUS associated with severe neurological involvement, hemodynamic instability, and AKI requires intensive care and focused therapy.Fil: Luna, Mariana. Gobierno de la Provincia de Mendoza. Hospital Pediátrico Humberto Notti; ArgentinaFil: Kamariski, Mariana. Gobierno de la Provincia de Mendoza. Hospital Pediátrico Humberto Notti; ArgentinaFil: Principi, Iliana. Gobierno de la Provincia de Mendoza. Hospital Pediátrico Humberto Notti; ArgentinaFil: Bocanegra, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Garramuño, Patricia. Universidad Nacional de Cuyo; Argentina. Gobierno de la Provincia de Mendoza. Hospital Pediátrico Humberto Notti; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentin

Inflammation in Acute Kidney Injury: Focus on Toll-Like Receptors

The molecular mechanisms of acute kidney injury (AKI) remain unclear. AKI is known to be associated with intrarenal and systemic inflammation. The innate immune system plays an important role as a first response to tissue injury. Toll-like receptors (TLRs), the first identified and best studied family of pattern recognition receptors, are key regulators of the inflammatory response and have been associated with many cellular processes activated during AKI. These receptors are expressed on a variety of cell types, including epithelial cells, endothelia, dendritic cells, monocytes/macrophages, and B and T cells. TLRs initiate innate immune responses and shape the subsequent adaptive immune response. Pathogen-associated molecular patterns (PAMPS), which are the conserved microbial motifs, are sensed by these receptors. Increasingly recognized is that endogenous molecules generated during tissue injury and labeled as damage-associated molecular pattern molecules (DAMPs), can also activate pattern recognition receptorsFil: Valles, Patricia G.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Cátedra de Fisiología Patológica; ArgentinaFil: Gil Lorenzo, Andrea Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Cátedra de Fisiología Patológica; ArgentinaFil: Bocanegra, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Cacciamani, Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Benardon, María Eugenia. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Cátedra de Fisiología Patológica; ArgentinaFil: Costantino, Valeria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina. Universidad Nacional de Cuyo. Facultad de Cs.medicas. Area Quimica Biologica; Argentin

RhoA and MAPKinase signal transduction pathways regulate NHE1 Na+/H+ exchanger-dependent proximal tubule cell apoptosis following mechanical stretch

Mechanical deformation after congenital ureteral obstruction is traduced into biochemical signals leading to tubular atrophy due to epithelial cell apoptosis. We investigated whether Na+/H+ exchanger 1 (NHE1) could be responsible for HK-2 cell apoptosis induction in response to mechanical stretch through its ability to function as a control point of RhoA and MAPK signaling pathways. When mechanical stretch was applied to HK-2 cells, cell apoptosis was associated with diminished NHE1 expression and RhoA activation. The RhoA signaling pathway was confirmed to be upstream from the MAPK cascade when HK-2 cells were transfected with the active RhoA-V14 mutant, showing higher ERK1/2 expression and decreased p38 activation associated with NHE1 downregulation. NHE1 participation in apoptosis induction was confirmed by specific small interfering RNA NHE1 showing caspase-3 activation and decreased Bcl-2 expression. The decreased NHE1 expression was correlated with abnormal NHE1 activity addressed by intracellular pH measurements. These results demonstrate that mitochondrial proximal tubule cell apoptosis in response to mechanical stretch is orchestrated by signaling pathways initiated by the small GTPase RhoA and followed by the opposing effects of ERK1/2 and p38 MAPK phosphorylation, regulating NHE1 decreased expression and activity.Fil: Bocanegra, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Gil Lorenzo, Andrea Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Cacciamani, Valeria. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; ArgentinaFil: Benardon, María Eugenia. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; ArgentinaFil: Costantino, Valeria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Vallés, Patricia G.. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentin