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Current therapies for Fabry disease are based on reversing intracellular accumulation of globotriaosylceramide (Gb3) by enzyme replacement therapy (ERT) or chaperone-mediated stabilization of the defective enzyme, thereby alleviating lysosomal dysfunction. However, their effect in the reversal of end-organ damage, like kidney injury and chronic kidney disease, remains unclear. In this study, ultrastructural analysis of serial human kidney biopsies showed that long-term use of ERT reduced Gb3 accumulation in podocytes but did not reverse podocyte injury. Then, a CRISPR/Cas9-mediated α-galactosidase knockout podocyte cell line confirmed ERT-mediated reversal of Gb3 accumulation without resolution of lysosomal dysfunction. Transcriptome-based connectivity mapping and SILAC-based quantitative proteomics identified α-synuclein (SNCA) accumulation as a key event mediating podocyte injury. Genetic and pharmacological inhibition of SNCA improved lysosomal structure and function in Fabry podocytes, exceeding the benefits of ERT. Together, this work reconceptualizes Fabry-associated cell injury beyond Gb3 accumulation, and introduces SNCA modulation as a potential intervention, especially for patients with Fabry nephropathy.
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Enfermedad de Fabry , Podocitos , Humanos , Podocitos/patología , alfa-Sinucleína/genética , alfa-Sinucleína/metabolismo , Enfermedad de Fabry/genética , Enfermedad de Fabry/tratamiento farmacológico , Enfermedad de Fabry/patología , alfa-Galactosidasa/genética , alfa-Galactosidasa/metabolismo , alfa-Galactosidasa/uso terapéutico , Riñón/metabolismo , Trihexosilceramidas/metabolismo , Trihexosilceramidas/farmacología , Trihexosilceramidas/uso terapéuticoRESUMEN
Expansion microscopy physically enlarges biological specimens to achieve nanoscale resolution using diffraction-limited microscopy systems1. However, optimal performance is usually reached using laser-based systems (for example, confocal microscopy), restricting its broad applicability in clinical pathology, as most centres have access only to light-emitting diode (LED)-based widefield systems. As a possible alternative, a computational method for image resolution enhancement, namely, super-resolution radial fluctuations (SRRF)2,3, has recently been developed. However, this method has not been explored in pathology specimens to date, because on its own, it does not achieve sufficient resolution for routine clinical use. Here, we report expansion-enhanced super-resolution radial fluctuations (ExSRRF), a simple, robust, scalable and accessible workflow that provides a resolution of up to 25 nm using LED-based widefield microscopy. ExSRRF enables molecular profiling of subcellular structures from archival formalin-fixed paraffin-embedded tissues in complex clinical and experimental specimens, including ischaemic, degenerative, neoplastic, genetic and immune-mediated disorders. Furthermore, as examples of its potential application to experimental and clinical pathology, we show that ExSRRF can be used to identify and quantify classical features of endoplasmic reticulum stress in the murine ischaemic kidney and diagnostic ultrastructural features in human kidney biopsies.
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Aumento de la Imagen , Riñón , Animales , Humanos , Ratones , Microscopía Fluorescente/métodos , Microscopía Confocal/métodosRESUMEN
The P2X7 ion channel is a key sensor for extracellular ATP and a key trigger of sterile inflammation. Intravenous injection of nanobodies that block P2X7 has shown to be beneficial in mouse models of systemic inflammation. P2X7 has also emerged as an attractive therapeutic target for inflammatory brain diseases. However, little is known about the ability of nanobodies to cross the BBB. Here we evaluated the ability of P2X7-specific nanobodies to reach and to block P2X7 on microglia following intravenous or intracerebral administration. For this study, we reformatted and sequence-optimized P2X7 nanobodies for higher stability and elevated isoelectric point. Following injection of nanobodies or nanobody-encoding adeno-associated viral vectors (AAV), we monitored the occupancy and blockade of microglial P2X7 in vivo using ex vivo flow cytometry. Our results show that P2X7 on microglia was within minutes completely occupied and blocked by intracerebroventricularly injected nanobodies, even at low doses. In contrast, very high doses were required to achieve similar effects when injected intravenously. The endogenous production of P2X7-antagonistic nanobodies following intracerebral or intramuscular injection of nanobody-encoding AAVs resulted in a long-term occupancy and blockade of P2X7 on microglia. Our results provide new insights into the conditions for the delivery of nanobodies to microglial P2X7 and point to AAV-mediated delivery of P2X7 nanobodies as a promising strategy for the treatment of sterile brain inflammation.
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The 13th International Podocyte Conference was held in Manchester, UK, and online from July 28 to 30, 2021. Originally planned for 2020, this biannual meeting was postponed by a year because of the coronavirus disease 2019 (COVID-19) pandemic and proceeded as an innovative hybrid meeting. In addition to in-person attendance, online registration was offered, and this attracted 490 conference registrations in total. As a Podocyte Conference first, a day for early-career researchers was introduced. This premeeting included talks from graduate students and postdoctoral researchers. It gave early career researchers the opportunity to ask a panel, comprising academic leaders and journal editors, about career pathways and the future for podocyte research. The main meeting over 3 days included a keynote talk and 4 focused sessions each day incorporating invited talks, followed by selected abstract presentations, and an open panel discussion. The conference concluded with a Patient Day, which brought together patients, clinicians, researchers, and industry representatives. The Patient Day was an interactive and diverse day. As well as updates on improving diagnosis and potential new therapies, the Patient Day included a PodoArt competition, exercise and cooking classes with practical nutrition advice, and inspirational stories from patients and family members. This review summarizes the exciting science presented during the 13th International Podocyte Conference and demonstrates the resilience of researchers during a global pandemic.
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COVID-19 , Podocitos , COVID-19/epidemiología , Humanos , Investigación Biomédica TraslacionalRESUMEN
Extrapulmonary manifestations of COVID-19 have gained attention due to their links to clinical outcomes and their potential long-term sequelae1. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) displays tropism towards several organs, including the heart and kidney. Whether it also directly affects the liver has been debated2,3. Here we provide clinical, histopathological, molecular and bioinformatic evidence for the hepatic tropism of SARS-CoV-2. We find that liver injury, indicated by a high frequency of abnormal liver function tests, is a common clinical feature of COVID-19 in two independent cohorts of patients with COVID-19 requiring hospitalization. Using autopsy samples obtained from a third patient cohort, we provide multiple levels of evidence for SARS-CoV-2 liver tropism, including viral RNA detection in 69% of autopsy liver specimens, and successful isolation of infectious SARS-CoV-2 from liver tissue postmortem. Furthermore, we identify transcription-, proteomic- and transcription factor-based activity profiles in hepatic autopsy samples, revealing similarities to the signatures associated with multiple other viral infections of the human liver. Together, we provide a comprehensive multimodal analysis of SARS-CoV-2 liver tropism, which increases our understanding of the molecular consequences of severe COVID-19 and could be useful for the identification of organ-specific pharmacological targets.
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COVID-19 , SARS-CoV-2 , Humanos , Hígado , Proteómica , TropismoRESUMEN
Hypoxia-induced intrauterine growth restriction increases the risk for cardiovascular, renal, and other chronic diseases in adults, representing thus a major public health problem. Still, not much is known about the fetal mechanisms that predispose these individuals to disease. Using a previously validated mouse model of fetal hypoxia and bottom-up proteomics, we characterize the response of the fetal kidney to chronic hypoxic stress. Fetal kidneys exhibit a dichotomous response to chronic hypoxia, comprising on the one hand cellular adaptations that promote survival (glycolysis, autophagy, and reduced DNA and protein synthesis), but on the other processes that induce a senescence-like phenotype (infiltration of inflammatory cells, DNA damage, and reduced proliferation). Importantly, chronic hypoxia also reduces the expression of the antiaging proteins klotho and Sirt6, a mechanism that is evolutionary conserved between mice and humans. Taken together, we uncover that predetermined aging during fetal development is a key event in chronic hypoxia, establishing a solid foundation for Barker's hypothesis of fetal programming of adult diseases. This phenotype is associated with a characteristic biomarker profile in tissue and serum samples, exploitable for detecting and targeting accelerated aging in chronic hypoxic human diseases.
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Hipoxia Fetal , Sirtuinas , Envejecimiento , Animales , Desarrollo Fetal , Hipoxia , Ratones , FenotipoRESUMEN
In utero renal development is subject to maternal metabolic and environmental influences affecting long-term renal function and the risk of developing chronic kidney failure and cardiovascular disease. Epigenetic processes have been implicated in the orchestration of renal development and prenatal programming of nephron number. However, the role of many epigenetic modifiers for kidney development is still unclear. Bromodomain and extra-terminal domain (BET) proteins act as histone acetylation reader molecules and promote gene transcription. BET family members Brd2, Brd3 and Brd4 are expressed in the nephrogenic zone during kidney development. Here, the effect of the BET inhibitor JQ1 on renal development is evaluated. Inhibition of BET proteins via JQ1 leads to reduced growth of metanephric kidney cultures, loss of the nephron progenitor cell population, and premature and disturbed nephron differentiation. Gene expression of key nephron progenitor transcription factor Osr1 is downregulated after 24 h BET inhibition, while Lhx1 and Pax8 expression is increased. Mining of BRD4 ChIP-seq and gene expression data identify Osr1 as a key factor regulated by BRD4-controlled gene activation. Inhibition of BRD4 by BET inhibitor JQ1 leads to downregulation of Osr1, thereby causing a disturbance in the balance of nephron progenitor cell self-renewal and premature differentiation of the nephron, which ultimately leads to kidney hypoplasia and disturbed nephron development. This raises questions about the potential teratogenic effects of BET inhibitors for embryonic development. In summary, our work highlights the role of BET proteins for prenatal programming of nephrogenesis and identifies Osr1 as a potential target of BET proteins.
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Skeletal muscle wasting is commonly associated with chronic kidney disease (CKD), resulting in increased morbidity and mortality. However, the link between kidney and muscle function remains poorly understood. Here, we took a complementary interorgan approach to investigate skeletal muscle wasting in CKD. We identified increased production and elevated blood levels of soluble pro-cachectic factors, including activin A, directly linking experimental and human CKD to skeletal muscle wasting programs. Single-cell sequencing data identified the expression of activin A in specific kidney cell populations of fibroblasts and cells of the juxtaglomerular apparatus. We propose that persistent and increased kidney production of pro-cachectic factors, combined with a lack of kidney clearance, facilitates a vicious kidney/muscle signaling cycle, leading to exacerbated blood accumulation and, thereby, skeletal muscle wasting. Systemic pharmacological blockade of activin A using soluble activin receptor type IIB ligand trap as well as muscle-specific adeno-associated virus-mediated downregulation of its receptor ACVR2A/B prevented muscle wasting in different mouse models of experimental CKD, suggesting that activin A is a key factor in CKD-induced cachexia. In summary, we uncovered a crosstalk between kidney and muscle and propose modulation of activin signaling as a potential therapeutic strategy for skeletal muscle wasting in CKD.
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Caquexia/metabolismo , Músculo Esquelético/metabolismo , Atrofia Muscular/metabolismo , Insuficiencia Renal Crónica/metabolismo , Síndrome Debilitante/metabolismo , Receptores de Activinas Tipo II/genética , Receptores de Activinas Tipo II/metabolismo , Activinas/genética , Activinas/metabolismo , Animales , Caquexia/etiología , Caquexia/genética , Modelos Animales de Enfermedad , Células HEK293 , Humanos , Ratones , Ratones Noqueados , Atrofia Muscular/etiología , Atrofia Muscular/genética , Insuficiencia Renal Crónica/complicaciones , Insuficiencia Renal Crónica/genética , Síndrome Debilitante/etiología , Síndrome Debilitante/genéticaRESUMEN
Current therapeutic options for renal diseases are limited, and the search for disease-specific treatments is ongoing. Nanobodies, single-domain antibodies with many advantages over conventional antibodies, provide flexible, easy-to-format biologicals with many possible applications. Here, we discuss the potential use of nanobodies for renal diseases.
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Enfermedades Renales/terapia , Anticuerpos de Dominio Único/uso terapéutico , Animales , HumanosRESUMEN
A growing body of evidence suggests that low nephron numbers at birth can increase the risk of chronic kidney disease or hypertension later in life. Environmental stressors, such as maternal malnutrition, medication and smoking, can influence renal size at birth. Using metanephric organ cultures to model single-variable environmental conditions, models of maternal disease were evaluated for patterns of developmental impairment. While hyperthermia had limited effects on renal development, fetal iron deficiency was associated with severe impairment of renal growth and nephrogenesis with an all-proximal phenotype. Culturing kidney explants under high glucose conditions led to cellular and transcriptomic changes resembling human diabetic nephropathy. Short-term high glucose culture conditions were sufficient for long-term alterations in DNA methylation-associated epigenetic memory. Finally, the role of epigenetic modifiers in renal development was tested using a small compound library. Among the selected epigenetic inhibitors, various compounds elicited an effect on renal growth, such as HDAC (entinostat, TH39), histone demethylase (deferasirox, deferoxamine) and histone methyltransferase (cyproheptadine) inhibitors. Thus, metanephric organ cultures provide a valuable system for studying metabolic conditions and a tool for screening for epigenetic modifiers in renal development.
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Nefropatías Diabéticas/genética , Ambiente , Epigénesis Genética , Glucosa/toxicidad , Riñón/metabolismo , Efectos Tardíos de la Exposición Prenatal/genética , Animales , Metilación de ADN , Femenino , Humanos , Deficiencias de Hierro , Riñón/efectos de los fármacos , Ratones , Técnicas de Cultivo de Órganos/métodos , Embarazo , TranscriptomaRESUMEN
Morphologic examination of tissue biopsies is essential for histopathological diagnosis. However, accurate and scalable cellular quantification in human samples remains challenging. Here, we present a deep learning-based approach for antigen-specific cellular morphometrics in human kidney biopsies, which combines indirect immunofluorescence imaging with U-Net-based architectures for image-to-image translation and dual segmentation tasks, achieving human-level accuracy. In the kidney, podocyte loss represents a hallmark of glomerular injury and can be estimated in diagnostic biopsies. Thus, we profiled over 27,000 podocytes from 110 human samples, including patients with antineutrophil cytoplasmic antibody-associated glomerulonephritis (ANCA-GN), an immune-mediated disease with aggressive glomerular damage and irreversible loss of kidney function. We identified previously unknown morphometric signatures of podocyte depletion in patients with ANCA-GN, which allowed patient classification and, in combination with routine clinical tools, showed potential for risk stratification. Our approach enables robust and scalable molecular morphometric analysis of human tissues, yielding deeper biological insights into the human kidney pathophysiology.
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Vasculitis Asociada a Anticuerpos Citoplasmáticos Antineutrófilos/patología , Aprendizaje Profundo , Diagnóstico por Computador/métodos , Procesamiento de Imagen Asistido por Computador/métodos , Riñón/patología , Biopsia , Estudios de Casos y Controles , Humanos , Patología Clínica/métodos , Podocitos/citología , Podocitos/patologíaRESUMEN
Podocyte maintenance and stress resistance are exquisitely based on high basal rates of autophagy making these cells a unique model to unravel mechanisms of autophagy regulation. Polyamines have key cellular functions such as proliferation, nucleic acid biosynthesis and autophagy. Here we test whether endogenous spermidine signaling is a driver of basal and dynamic autophagy in podocytes by using genetic and pharmacologic approaches to interfere with different steps of polyamine metabolism. Translational studies revealed altered spermidine signaling in focal segmental glomerulosclerosis in vivo and in vitro. Exogenous spermidine supplementation emerged as new treatment strategy by successfully activating autophagy in vivo via inhibition of EP300, a protein with an essential role in controlling cell growth, cell division and prompting cells to differentiate to take on specialized functions. Surprisingly, gas chromatography-mass spectroscopy based untargeted metabolomics of wild type and autophagy deficient primary podocytes revealed a positive feedback mechanism whereby autophagy itself maintains polyamine metabolism and spermidine synthesis. The transcription factor MAFB acted as an upstream regulator of polyamine metabolism. Thus, our data highlight a novel positive feedback loop of autophagy and spermidine signaling allowing maintenance of high basal levels of autophagy as a key mechanism to sustain the filtration barrier. Hence, spermidine supplementation may emerge as a new therapeutic to restore autophagy in glomerular disease.
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Glomeruloesclerosis Focal y Segmentaria , Podocitos , Espermidina , Autofagia , Proliferación Celular , Humanos , Espermidina/metabolismoAsunto(s)
Betacoronavirus/fisiología , Riñón/virología , Carga Viral , Tropismo Viral , Anciano , Anciano de 80 o más Años , Autopsia , Betacoronavirus/aislamiento & purificación , Encéfalo/virología , COVID-19 , Infecciones por Coronavirus , Femenino , Corazón/virología , Humanos , Hígado/virología , Pulmón/virología , Masculino , Persona de Mediana Edad , Pandemias , Faringe/virología , Neumonía Viral , SARS-CoV-2RESUMEN
The cellular origins of glomerulosclerosis involve activation of parietal epithelial cells (PECs) and progressive podocyte depletion. While mammalian target of rapamycin-mediated (mTOR-mediated) podocyte hypertrophy is recognized as an important signaling pathway in the context of glomerular disease, the role of podocyte hypertrophy as a compensatory mechanism preventing PEC activation and glomerulosclerosis remains poorly understood. In this study, we show that glomerular mTOR and PEC activation-related genes were both upregulated and intercorrelated in biopsies from patients with focal segmental glomerulosclerosis (FSGS) and diabetic nephropathy, suggesting both compensatory and pathological roles. Advanced morphometric analyses in murine and human tissues identified podocyte hypertrophy as a compensatory mechanism aiming to regulate glomerular functional integrity in response to somatic growth, podocyte depletion, and even glomerulosclerosis - all of this in the absence of detectable podocyte regeneration. In mice, pharmacological inhibition of mTOR signaling during acute podocyte loss impaired hypertrophy of remaining podocytes, resulting in unexpected albuminuria, PEC activation, and glomerulosclerosis. Exacerbated and persistent podocyte hypertrophy enabled a vicious cycle of podocyte loss and PEC activation, suggesting a limit to its beneficial effects. In summary, our data highlight a critical protective role of mTOR-mediated podocyte hypertrophy following podocyte loss in order to preserve glomerular integrity, preventing PEC activation and glomerulosclerosis.
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Albuminuria/inducido químicamente , Nefropatías Diabéticas/patología , Everolimus/efectos adversos , Glomeruloesclerosis Focal y Segmentaria/patología , Serina-Treonina Quinasas TOR/metabolismo , Anciano , Anciano de 80 o más Años , Animales , Biopsia , Células Cultivadas , Preescolar , Conjuntos de Datos como Asunto , Diabetes Mellitus Experimental/inducido químicamente , Diabetes Mellitus Experimental/complicaciones , Diabetes Mellitus Experimental/patología , Nefropatías Diabéticas/tratamiento farmacológico , Células Epiteliales/patología , Everolimus/administración & dosificación , Femenino , Perfilación de la Expresión Génica , Humanos , Hipertrofia/tratamiento farmacológico , Hipertrofia/patología , Lactante , Masculino , Ratones , Ratones Noqueados , Persona de Mediana Edad , Podocitos , Cultivo Primario de Células , Regeneración , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , Estreptozocina/toxicidad , Serina-Treonina Quinasas TOR/análisis , Serina-Treonina Quinasas TOR/antagonistas & inhibidores , Proteína 1 del Complejo de la Esclerosis Tuberosa/genética , Proteína 1 del Complejo de la Esclerosis Tuberosa/metabolismo , Regulación hacia Arriba , Adulto JovenRESUMEN
The podocyte is a key component of the glomerular filtration barrier. Podocyte dysfunction is central to the underlying pathophysiology of many common glomerular diseases, including diabetic nephropathy, glomerulonephritis and genetic forms of nephrotic syndrome. Collectively, these conditions affect millions of people worldwide, and account for the majority of kidney diseases requiring dialysis and transplantation. The 12th International Podocyte Conference was held in Montreal, Canada from May 30 to June 2, 2018. The primary aim of this conference was to bring together nephrologists, clinician scientists, basic scientists and their trainees from all over the world to present their research and to establish networks with the common goal of developing new therapies for glomerular diseases based on the latest advances in podocyte biology. This review briefly highlights recent advances made in understanding podocyte structure and metabolism, experimental systems in which to study podocytes and glomerular disease, disease mediators, genetic and immune origins of glomerulopathies, and the development of novel therapeutic agents to protect podocyte and glomerular injury.
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Nefropatías Diabéticas/terapia , Barrera de Filtración Glomerular/fisiopatología , Glomerulonefritis/terapia , Síndrome Nefrótico/terapia , Podocitos/patología , Animales , Canadá , Congresos como Asunto , Nefropatías Diabéticas/patología , Nefropatías Diabéticas/fisiopatología , Glomerulonefritis/patología , Glomerulonefritis/fisiopatología , Humanos , Síndrome Nefrótico/patología , Síndrome Nefrótico/fisiopatologíaRESUMEN
BACKGROUND: Nephron number is a major determinant of long-term renal function and cardiovascular risk. Observational studies suggest that maternal nutritional and metabolic factors during gestation contribute to the high variability of nephron endowment. However, the underlying molecular mechanisms have been unclear. METHODS: We used mouse models, including DNA methyltransferase (Dnmt1, Dnmt3a, and Dnmt3b) knockout mice, optical projection tomography, three-dimensional reconstructions of the nephrogenic niche, and transcriptome and DNA methylation analysis to characterize the role of DNA methylation for kidney development. RESULTS: We demonstrate that DNA hypomethylation is a key feature of nutritional kidney growth restriction in vitro and in vivo, and that DNA methyltransferases Dnmt1 and Dnmt3a are highly enriched in the nephrogenic zone of the developing kidneys. Deletion of Dnmt1 in nephron progenitor cells (in contrast to deletion of Dnmt3a or Dnm3b) mimics nutritional models of kidney growth restriction and results in a substantial reduction of nephron number as well as renal hypoplasia at birth. In Dnmt1-deficient mice, optical projection tomography and three-dimensional reconstructions uncovered a significant reduction of stem cell niches and progenitor cells. RNA sequencing analysis revealed that global DNA hypomethylation interferes in the progenitor cell regulatory network, leading to downregulation of genes crucial for initiation of nephrogenesis, Wt1 and its target Wnt4. Derepression of germline genes, protocadherins, Rhox genes, and endogenous retroviral elements resulted in the upregulation of IFN targets and inhibitors of cell cycle progression. CONCLUSIONS: These findings establish DNA methylation as a key regulatory event of prenatal renal programming, which possibly represents a fundamental link between maternal nutritional factors during gestation and reduced nephron number.
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ADN (Citosina-5-)-Metiltransferasa 1/genética , ADN (Citosina-5-)-Metiltransferasas/genética , Riñón/embriología , Organogénesis/genética , Células Madre/citología , Animales , Diferenciación Celular/genética , Células Cultivadas , Metilación de ADN , Regulación del Desarrollo de la Expresión Génica/genética , Inmunohistoquímica , Ratones , Ratones Noqueados , Nefronas/citología , Nefronas/fisiología , Ratas , Ratas Wistar , Sensibilidad y Especificidad , Células Madre/fisiología , ADN Metiltransferasa 3BRESUMEN
The role of CX3CR1, also known as fractalkine receptor, in hypertension is unknown. The present study determined the role of the fractalkine receptor CX3CR1 in hypertensive renal and cardiac injury. Expression of CX3CR1 was determined using CX3CR1GFP/+ mice that express a green fluorescent protein (GFP) reporter in CX3CR1+ cells. FACS analysis of leukocytes isolated from the kidney showed that 34% of CD45+ cells expressed CX3CR1. Dendritic cells were the majority of positive cells (67%) followed by macrophages (10%), NK cells (6%), and T cells (10%). With the use of confocal microscopy, the receptor was detected in the kidney only on infiltrating cells but not on resident renal cells. To evaluate the role of CX3CR1 in hypertensive end-organ injury, an aggravated model of hypertension was used. Unilateral nephrectomy was performed followed by infusion of angiotensin II (ANG II, 1.5 ng·g-1·min-1) and a high-salt diet in wild-type ( n = 15) and CX3CR1-deficient mice ( n = 18). CX3CR1 deficiency reduced the number of renal dendritic cells and increased the numbers of renal CD11b/F4/80+ macrophages and CD11b/Ly6G+ neutrophils in ANG II-infused mice. Surprisingly, CX3CR1-deficient mice exhibited increased albuminuria, glomerular injury, and reduced podocyte density in spite of similar levels of arterial hypertension. In contrast, cardiac damage as assessed by increased heart weight, cardiac fibrosis, and expression of fetal genes, and matrix components were not different between both genotypes. Our findings suggest that CX3CR1 exerts protective properties by modulating the invasion of inflammatory cells in hypertensive renal injury. CX3CR1 inhibition should be avoided in hypertension because it may promote hypertensive renal injury.
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Angiotensina II , Presión Arterial , Receptor 1 de Quimiocinas CX3C/metabolismo , Células Dendríticas/metabolismo , Hipertensión/metabolismo , Enfermedades Renales/prevención & control , Riñón/metabolismo , Leucocitos/metabolismo , Macrófagos/metabolismo , Albuminuria/metabolismo , Albuminuria/fisiopatología , Albuminuria/prevención & control , Animales , Receptor 1 de Quimiocinas CX3C/deficiencia , Receptor 1 de Quimiocinas CX3C/genética , Quimiotaxis de Leucocito , Modelos Animales de Enfermedad , Hipertensión/inducido químicamente , Hipertensión/genética , Hipertensión/fisiopatología , Riñón/patología , Riñón/fisiopatología , Enfermedades Renales/genética , Enfermedades Renales/metabolismo , Enfermedades Renales/patología , Células Asesinas Naturales/metabolismo , Masculino , Ratones Endogámicos C57BL , Ratones Noqueados , Infiltración Neutrófila , Neutrófilos/metabolismo , Neutrófilos/patología , Transducción de Señal , Linfocitos T/metabolismo , Linfocitos T/patologíaRESUMEN
Podocyte and glomerular research is center stage for the development of improved preventive and therapeutic strategies for chronic progressive kidney diseases. Held April 3-6, 2016, the 11th International Podocyte Conference took place in Haifa and Jerusalem, Israel, where participants from all over the world presented their work on new developments in podocyte research. In this review, we briefly highlight the advances made in characterizing the mechanisms involved in podocyte development, metabolism, acquired injury, and repair, including progress in determining the roles of genetic variants and microRNA in particular, as well as the advances made in diagnostic techniques and therapeutics.
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Enfermedades Renales/etiología , Glomérulos Renales/fisiología , Podocitos/fisiología , Animales , Investigación Biomédica , Humanos , Enfermedades Renales/diagnóstico , Enfermedades Renales/terapia , MicroARNs/fisiología , Podocitos/ultraestructura , Transducción de Señal , Células MadreRESUMEN
Mammalian target of rapamycin (mTOR) signaling is involved in a variety of kidney diseases. Clinical trials administering mTOR inhibitors to patients with FSGS, a prototypic podocyte disease, led to conflicting results, ranging from remission to deterioration of kidney function. Here, we combined complex genetic titration of mTOR complex 1 (mTORC1) levels in murine glomerular disease models, pharmacologic studies, and human studies to precisely delineate the role of mTOR in FSGS. mTORC1 target genes were significantly induced in microdissected glomeruli from both patients with FSGS and a murine FSGS model. Furthermore, a mouse model with constitutive mTORC1 activation closely recapitulated human FSGS. Notably, the complete knockout of mTORC1 by induced deletion of both Raptor alleles accelerated the progression of murine FSGS models. However, lowering mTORC1 signaling by deleting just one Raptor allele ameliorated the progression of glomerulosclerosis. Similarly, low-dose treatment with the mTORC1 inhibitor rapamycin efficiently diminished disease progression. Mechanistically, complete pharmacologic inhibition of mTOR in immortalized podocytes shifted the cellular energy metabolism toward reduced rates of oxidative phosphorylation and anaerobic glycolysis, which correlated with increased production of reactive oxygen species. Together, these data suggest that podocyte injury and loss is commonly followed by adaptive mTOR activation. Prolonged mTOR activation, however, results in a metabolic podocyte reprogramming leading to increased cellular stress and dedifferentiation, thus offering a treatment rationale for incomplete mTOR inhibition.