CD154 Induces Interleukin-6 Secretion by Kidney Tubular Epithelial Cells under Hypoxic Conditions: Inhibition by Chloroquine

Funder: MSDAvenirInflammation is a major contributor to tubular epithelium injury in kidney disorders, and the involvement of blood platelets in driving inflammation is increasingly stressed. CD154, the ligand of CD40, is one of the mediators supporting platelet proinflammatory properties. Although hypoxia is an essential constituent of the inflammatory reaction, if and how platelets and CD154 regulate inflammation in hypoxic conditions remain unclear. Here, we studied the control by CD154 of the proinflammatory cytokine interleukin- (IL-) 6 secretion in short-term oxygen (O2) deprivation conditions, using the HK-2 cell line as a kidney tubular epithelial cell (TEC) model. IL-6 secretion was markedly stimulated by CD154 after 1 to 3 hours of hypoxic stress. Both intracellular IL-6 expression and secretion were stimulated by CD154 and associated with a strong upregulation of IL-6 mRNA and increased transcription. Searching for inhibitors of CD154-mediated IL-6 production by HK-2 cells in hypoxic conditions, we observed that chloroquine, a drug that has been repurposed as an anti-inflammatory agent, alleviated this induction. Therefore, CD154 is a potent early stimulus for IL-6 secretion by TECs in O2 deprivation conditions, a mechanism likely to take part in the deleterious inflammatory consequences of platelet activation in kidney tubular injury. The inhibition of CD154-induced IL-6 production by chloroquine suggests the potential usefulness of this drug as a therapeutic adjunct in conditions associated with acute kidney injury

Int. J. Mol. Sci.

To face the increasing demand for organ transplantation, currently the development of tissue engineering appears as the best opportunity to effectively regenerate functional tissues and organs. However, these approaches still face the lack of an efficient method to produce an efficient vascularization system. To answer these issues, the formation of an intra-volume channel within a three-dimensional, scaffold free, mature, and cell-covered collagen microfibre is here investigated through laser-induced cavitation. An intra-volume channel was formed upon irradiation with a near-infrared, femtosecond laser beam, focused with a high numerical aperture lens. The laser beam directly crossed the surface of a dense and living-cell bilayer and was focused behind the bilayer to induce channel formation in the hydrogel core while preserving the cell bilayer. Channel formation was assessed through confocal microscopy. Channel generation inside the hydrogel core was enhanced by the formation of voluminous cavitation bubbles with a lifetime longer than 30 s, which also improved intra-volume channel durability. Twenty-four hours after laser processing, cellular viability dropped due to a lack of sufficient hydration for processing longer than 10 min. However, the processing automation could drastically reduce the cellular mortality, this way enabling the formation of hollowed microfibres with a high density of living-cell outer bilayer

Safety of meglumine gadoterate (Gd-DOTA)-enhanced MRI compared to unenhanced MRI in patients with chronic kidney disease (RESCUE study)

OBJECTIVE: To prospectively compare the renal safety of meglumine gadoterate (Gd-DOTA)-enhanced magnetic resonance imaging (MRI) to a control group (unenhanced MRI) in high-risk patients. METHODS: Patients with chronic kidney disease (CKD) scheduled for MRI procedures were screened. The primary endpoint was the percentage of patients with an elevation of serum creatinine levels, measured 72 ± 24 h after the MRI procedure, by at least 25 % or 44.2 μmol/l (0.5 mg/dl) from baseline. A non-inferiority margin of the between-group difference was set at −15 % for statistical analysis of the primary endpoint. Main secondary endpoints were the variation in serum creatinine and eGFR values between baseline and 72 ± 24 h after MRI and the percentage of patients with a decrease in eGFR of at least 25 % from baseline. Patients were screened for signs of nephrogenic systemic fibrosis (NSF) at 3-month follow-up. RESULTS: Among the 114 evaluable patients, one (1.4 %) in the Gd-DOTA-MRI group and none in the control group met the criteria of the primary endpoint [Δ = −1.4 %, 95%CI = (−7.9 %; 6.7 %)]. Non-inferiority was therefore demonstrated (P = 0.001). No clinically significant differences were observed between groups for the secondary endpoints. No serious safety events (including NSF) were noted. CONCLUSION: Meglumine gadoterate did not affect renal function and was a safe contrast agent in patients with CKD. KEY POINTS: • Contrast-induced nephropathy (CIN) is a potential problem following gadolinium administration for MRI. • Meglumine gadoterate (Gd-DOTA) appears safe, even in patients with chronic kidney disease. • Gd-DOTA only caused a temporary creatinine level increase in 1/70 such patients. • No case or sign of NSF was detected at 3-month follow-up

Characterization of acute kidney injury in critically ill patients with severe coronavirus disease 2019

Abstract Background Coronavirus disease 2019 (COVID-19)-associated acute kidney injury (AKI) frequency, severity and characterization in critically ill patients has not been reported. Methods Single-centre cohort performed from 3 March 2020 to 14 April 2020 in four intensive care units in Bordeaux University Hospital, France. All patients with COVID-19 and pulmonary severity criteria were included. AKI was defined using Kidney Disease: Improving Global Outcomes (KDIGO) criteria. A systematic urinary analysis was performed. The incidence, severity, clinical presentation, biological characterization (transient versus persistent AKI; proteinuria, haematuria and glycosuria) and short-term outcomes were evaluated. Results Seventy-one patients were included, with basal serum creatinine (SCr) of 69 ± 21 µmol/L. At admission, AKI was present in 8/71 (11%) patients. Median [interquartile range (IQR)] follow-up was 17 (12–23) days. AKI developed in a total of 57/71 (80%) patients, with 35% Stage 1, 35% Stage 2 and 30% Stage 3 AKI; 10/57 (18%) required renal replacement therapy (RRT). Transient AKI was present in only 4/55 (7%) patients and persistent AKI was observed in 51/55 (93%). Patients with persistent AKI developed a median (IQR) urine protein/creatinine of 82 (54–140) (mg/mmol) with an albuminuria/proteinuria ratio of 0.23 ± 20, indicating predominant tubulointerstitial injury. Only two (4%) patients had glycosuria. At Day 7 after onset of AKI, six (11%) patients remained dependent on RRT, nine (16%) had SCr >200 µmol/L and four (7%) had died. Day 7 and Day 14 renal recovery occurred in 28% and 52%, respectively. Conclusion Severe COVID-19-associated AKI is frequent, persistent, severe and characterized by an almost exclusive tubulointerstitial injury without glycosuria

IQGAP1 Interacts with Components of the Slit Diaphragm Complex in Podocytes and Is Involved in Podocyte Migration and Permeability In Vitro

IQGAP1 is a scaffold protein that interacts with proteins of the cytoskeleton and the intercellular adhesion complex. In podocytes, IQGAP1 is associated with nephrin in the glomerular slit diaphragm (SD) complex, but its role remains ill-defined. In this work, we investigated the interaction of IQGAP1 with the cytoskeleton and SD proteins in podocytes in culture, and its role in podocyte migration and permeability. Expression, localization, and interactions between IQGAP1 and SD or cytoskeletal proteins were determined in cultured human podocytes by Western blot (WB), immunocytolocalization (IC), immunoprecipitation (IP), and In situ Proximity Ligation assay (IsPL). Involvement of IQGAP1 in migration and permeability was also assessed. IQGAP1 expression in normal kidney biopsies was studied by immunohistochemistry. IQGAP1 expression by podocytes increased during their in vitro differentiation. IC, IP, and IsPL experiments showed colocalizations and/or interactions between IQGAP1 and SD proteins (nephrin, MAGI-1, CD2AP, NCK 1/2, podocin), podocalyxin, and cytoskeletal proteins (α-actinin-4). IQGAP1 silencing decreased podocyte migration and increased the permeability of a podocyte layer. Immunohistochemistry on normal human kidney confirmed IQGAP1 expression in podocytes and distal tubular epithelial cells and also showed an expression in glomerular parietal epithelial cells. In summary, our results suggest that IQGAP1, through its interaction with components of SD and cytoskeletal proteins, is involved in podocyte barrier properties

IQGAP1 protein in the podocyte : characterization and pathophysiology involvements

Le syndrome néphrotique idiopathique (SNI) se caractérise par un remodelage du cytosquelette des podocytes et par une réorganisation des complexes protéiques podocytaires dont le diaphragme de fente. Récemment, une protéine fondamentale dans le remodelage du cytosquelette a été identifiée au niveau des pédicelles : IQGAP1. Nous sommes partis de l’hypothèse selon laquelle IQGAP1 par ses propriétés et ses caractéristiques biologiques connues dans différents modèles cellulaires (protéine d’échafaudage, remodelage du cytosquelette, migration cellulaire) pourrait être fondamentale dans les modifications ultrastructurales observées au cours du SNI. Au cours de ce travail de thèse, nous avons analysé les caractéristiques de la protéine IQGAP1 dans les podocytes humains, son implication dans les fonctions podocytaires et dans la physiopathologie du SNI. Nous avons dans un premier temps caractérisé les propriétés de la protéine IQGAP1 au sein des podocytes et déterminé sa localisation cellulaire à l’interface entre le cytosquelette et les complexes protéiques apical et diaphragmatique. Nous avons démontré le rôle d’IQGAP1 dans la migration podocytaire et dans la perméabilité de la monocouche épithéliale. Ces phénomènes au cours du SNI étant modifiés, nous avons dans un second temps étudié l’implication d’IQGAP1 dans la physiopathologie du SNI à l’aide de différents modèles expérimentaux (aminonucléoside de puromycine, plasmas de patients présentant un SNI, podocytes mutés pour la PLCε1). Nous avons ainsi démontré la translocation nucléaire de la protéine IQGAP1, dépendante de la voie ERK et de la PLCε1 et son implication dans la survie cellulaire par son interaction avec la chromatine. Au cours du SNI expérimental, nous avons observé une modification des propriétés d’IQGAP1 : localisation, interactions, phosphorylation.Cette approche a permis de démontrer l’implication de la protéine IQGAP1 dans le SNI. Compte tenu de son rôle dans le remodelage du cytosquelette, IQGAP1 pourrait également être un facteur dans la genèse de différentes glomérulopathies.Idiopathic nephrotic syndrome (INS) is characterized by the pedicel cytoskeleton remodelling and the disruption of the slit diaphragm complex. Recently, a pivotal protein involved in cytoskeleton remodelling has been identified in podocytes: IQGAP1.We hypothesized that IQGAP1 may be crucial in ultrastructure changes observed in INS through its biological properties and characteristics reported in different cell types (scaffold protein, cytoskeleton dynamism, cell migration). Thus, we analysed IQGAP1 characteristics in human podocytes, its involvement in podocyte functions and in the INS pathophysiology. We have characterized IQGAP1 podocyte characteristics and clarified its cell localisation between the cytoskeleton and the apical or diaphragmatic protein complexes Our work demonstrated the role of IQGAP1 in podocyte motility and in the permeability of epithelial monolayer. With respect to the modification of these phenomenons during INS, we have studied IQGAP1 involvement in INS pathophysiology with different experimental models (puromycine aminonucleoside, plasmas from patients suffering from INS, PLCε1 mutated podocytes). We have demonstrated IQGAP1 nuclear translocation, dependant to ERK signaling pathway and to PLCε1 and its involvement in cell survival through its interaction with the chromatin. In the experimental INS, we have observed a modification of IQGAP1 properties: localization, interactions, phosphorylation. This approach allowed us to show IQGAP1 involvement in INS. Through its role in cytoskeleton remodelling, IQGAP1 may be a factor in the development of different glomerulopathies

IQGAP1 protein in the podocyte : characterization and pathophysiology involvements

Le syndrome néphrotique idiopathique (SNI) se caractérise par un remodelage du cytosquelette des podocytes et par une réorganisation des complexes protéiques podocytaires dont le diaphragme de fente. Récemment, une protéine fondamentale dans le remodelage du cytosquelette a été identifiée au niveau des pédicelles : IQGAP1. Nous sommes partis de l’hypothèse selon laquelle IQGAP1 par ses propriétés et ses caractéristiques biologiques connues dans différents modèles cellulaires (protéine d’échafaudage, remodelage du cytosquelette, migration cellulaire) pourrait être fondamentale dans les modifications ultrastructurales observées au cours du SNI. Au cours de ce travail de thèse, nous avons analysé les caractéristiques de la protéine IQGAP1 dans les podocytes humains, son implication dans les fonctions podocytaires et dans la physiopathologie du SNI. Nous avons dans un premier temps caractérisé les propriétés de la protéine IQGAP1 au sein des podocytes et déterminé sa localisation cellulaire à l’interface entre le cytosquelette et les complexes protéiques apical et diaphragmatique. Nous avons démontré le rôle d’IQGAP1 dans la migration podocytaire et dans la perméabilité de la monocouche épithéliale. Ces phénomènes au cours du SNI étant modifiés, nous avons dans un second temps étudié l’implication d’IQGAP1 dans la physiopathologie du SNI à l’aide de différents modèles expérimentaux (aminonucléoside de puromycine, plasmas de patients présentant un SNI, podocytes mutés pour la PLCε1). Nous avons ainsi démontré la translocation nucléaire de la protéine IQGAP1, dépendante de la voie ERK et de la PLCε1 et son implication dans la survie cellulaire par son interaction avec la chromatine. Au cours du SNI expérimental, nous avons observé une modification des propriétés d’IQGAP1 : localisation, interactions, phosphorylation.Cette approche a permis de démontrer l’implication de la protéine IQGAP1 dans le SNI. Compte tenu de son rôle dans le remodelage du cytosquelette, IQGAP1 pourrait également être un facteur dans la genèse de différentes glomérulopathies.Idiopathic nephrotic syndrome (INS) is characterized by the pedicel cytoskeleton remodelling and the disruption of the slit diaphragm complex. Recently, a pivotal protein involved in cytoskeleton remodelling has been identified in podocytes: IQGAP1.We hypothesized that IQGAP1 may be crucial in ultrastructure changes observed in INS through its biological properties and characteristics reported in different cell types (scaffold protein, cytoskeleton dynamism, cell migration). Thus, we analysed IQGAP1 characteristics in human podocytes, its involvement in podocyte functions and in the INS pathophysiology. We have characterized IQGAP1 podocyte characteristics and clarified its cell localisation between the cytoskeleton and the apical or diaphragmatic protein complexes Our work demonstrated the role of IQGAP1 in podocyte motility and in the permeability of epithelial monolayer. With respect to the modification of these phenomenons during INS, we have studied IQGAP1 involvement in INS pathophysiology with different experimental models (puromycine aminonucleoside, plasmas from patients suffering from INS, PLCε1 mutated podocytes). We have demonstrated IQGAP1 nuclear translocation, dependant to ERK signaling pathway and to PLCε1 and its involvement in cell survival through its interaction with the chromatin. In the experimental INS, we have observed a modification of IQGAP1 properties: localization, interactions, phosphorylation. This approach allowed us to show IQGAP1 involvement in INS. Through its role in cytoskeleton remodelling, IQGAP1 may be a factor in the development of different glomerulopathies

La protéine IQGAP1 dans le podocyte (caractérisation et implications physiopathologiques)

Le syndrome néphrotique idiopathique (SNI) se caractérise par un remodelage du cytosquelette des podocytes et par une réorganisation des complexes protéiques podocytaires dont le diaphragme de fente. Récemment, une protéine fondamentale dans le remodelage du cytosquelette a été identifiée au niveau des pédicelles : IQGAP1. Nous sommes partis de l hypothèse selon laquelle IQGAP1 par ses propriétés et ses caractéristiques biologiques connues dans différents modèles cellulaires (protéine d échafaudage, remodelage du cytosquelette, migration cellulaire) pourrait être fondamentale dans les modifications ultrastructurales observées au cours du SNI. Au cours de ce travail de thèse, nous avons analysé les caractéristiques de la protéine IQGAP1 dans les podocytes humains, son implication dans les fonctions podocytaires et dans la physiopathologie du SNI. Nous avons dans un premier temps caractérisé les propriétés de la protéine IQGAP1 au sein des podocytes et déterminé sa localisation cellulaire à l interface entre le cytosquelette et les complexes protéiques apical et diaphragmatique. Nous avons démontré le rôle d IQGAP1 dans la migration podocytaire et dans la perméabilité de la monocouche épithéliale. Ces phénomènes au cours du SNI étant modifiés, nous avons dans un second temps étudié l implication d IQGAP1 dans la physiopathologie du SNI à l aide de différents modèles expérimentaux (aminonucléoside de puromycine, plasmas de patients présentant un SNI, podocytes mutés pour la PLC 1). Nous avons ainsi démontré la translocation nucléaire de la protéine IQGAP1, dépendante de la voie ERK et de la PLC 1 et son implication dans la survie cellulaire par son interaction avec la chromatine. Au cours du SNI expérimental, nous avons observé une modification des propriétés d IQGAP1 : localisation, interactions, phosphorylation.Cette approche a permis de démontrer l implication de la protéine IQGAP1 dans le SNI. Compte tenu de son rôle dans le remodelage du cytosquelette, IQGAP1 pourrait également être un facteur dans la genèse de différentes glomérulopathies.Idiopathic nephrotic syndrome (INS) is characterized by the pedicel cytoskeleton remodelling and the disruption of the slit diaphragm complex. Recently, a pivotal protein involved in cytoskeleton remodelling has been identified in podocytes: IQGAP1.We hypothesized that IQGAP1 may be crucial in ultrastructure changes observed in INS through its biological properties and characteristics reported in different cell types (scaffold protein, cytoskeleton dynamism, cell migration). Thus, we analysed IQGAP1 characteristics in human podocytes, its involvement in podocyte functions and in the INS pathophysiology. We have characterized IQGAP1 podocyte characteristics and clarified its cell localisation between the cytoskeleton and the apical or diaphragmatic protein complexes Our work demonstrated the role of IQGAP1 in podocyte motility and in the permeability of epithelial monolayer. With respect to the modification of these phenomenons during INS, we have studied IQGAP1 involvement in INS pathophysiology with different experimental models (puromycine aminonucleoside, plasmas from patients suffering from INS, PLC 1 mutated podocytes). We have demonstrated IQGAP1 nuclear translocation, dependant to ERK signaling pathway and to PLC 1 and its involvement in cell survival through its interaction with the chromatin. In the experimental INS, we have observed a modification of IQGAP1 properties: localization, interactions, phosphorylation. This approach allowed us to show IQGAP1 involvement in INS. Through its role in cytoskeleton remodelling, IQGAP1 may be a factor in the development of different glomerulopathies.BORDEAUX2-Bib. électronique (335229905) / SudocSudocFranceF

Impact à long terme du taux de lymphocytes T Gamma-Delta sur le développement d'une dysfonction chronique du greffon (chez les sujets transplantés rénaux de 1998 à 2002)

BORDEAUX2-BU Santé (330632101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF