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1.
Diabetes Res Clin Pract ; 209: 111594, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38403176

RESUMEN

BACKGROUND: The relationship between Bowman's capsule thickening and progression of diabetic kidney disease (DKD) remains uncertain. METHODS: Renal biopsy specimens from 145 DKD patients and 20 control subjects were evaluated for Bowman's capsule thickness. Immunohistochemical staining assessed col4α2, laminin ß1, and albumin expression. In a discovery cohort of 111 DKD patients with eGFR ≥ 30 ml/min/1.73 m2, thickening was classified as fibrotic or exudative. The composite endpoint included CKD stage 5, dialysis initiation, and renal disease-related death. Prognosis was analyzed using Kaplan-Meier and Cox regression analyses. Two validation cohorts were included. RESULTS: Three types of thickening were observed: fibrotic, exudative, and periglomerular fibrosis. Parietal epithelial cell matrix protein accumulation contributed to fibrotic thickening, while albumin was present in exudative thickening. Bowman's capsule was significantly thicker in DKD patients (5.74 ± 2.09 µm) compared to controls (3.38 ± 0.43 µm, P < 0.01). In discovery cohort, the group of exudative thickning had a poorer prognosis(median time 20 months vs 57 months, P = 0.000). Cox multivariate analysis revealed that exudative thickening of Bowman's capsule were associated with a poor prognosis. The validation cohorts confirmed the result. CONCLUSIONS: Various mechanisms contribute to Bowman's capsule thickening in DKD. The proportion of exudative thickening may serve as a valuable prognostic indicator for DKD patients.


Asunto(s)
Diabetes Mellitus , Nefropatías Diabéticas , Fallo Renal Crónico , Humanos , Cápsula Glomerular/metabolismo , Cápsula Glomerular/patología , Nefropatías Diabéticas/patología , Fallo Renal Crónico/patología , Diálisis Renal , Albúminas , Diabetes Mellitus/patología
2.
Tohoku J Exp Med ; 261(1): 69-73, 2023 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-37495524

RESUMEN

X-linked Alport syndrome is a hereditary progressive renal disease resulting from the disruption of collagen α3α4α5 (IV) heterotrimerization caused by pathogenic variants in the COL4A5 gene. This study aimed to report a male case of X-linked Alport syndrome with a mild phenotype accompanied by an atypical expression pattern of type IV collagen α5 [α5 (IV)] chain in glomerulus. A 38-year-old male presented with proteinuria (2.3 g/day) and hematuria. He has been detected urinary protein and occult blood since childhood. A renal biopsy was performed at the age of 29 years; however, a diagnosis of Alport syndrome was not considered. A renal biopsy 9 years later revealed diffuse thinning and lamellation of the glomerular basement membrane. Α staining for α5 (IV) revealed a normal expression pattern in the glomerular basement membrane and a complete negative expression in Bowman's capsule and distal tubular basement membrane. Using next-generation sequencing, we detected a COL4A5 missense variant within exon 35 (NM_000495.5: c.3088G>A, p. G1030S). The possibility of X-linked Alport syndrome should be considered when negative expression of α5 (IV) staining on Bowman's capsule was observed.


Asunto(s)
Nefritis Hereditaria , Masculino , Humanos , Niño , Adulto , Nefritis Hereditaria/genética , Nefritis Hereditaria/metabolismo , Nefritis Hereditaria/patología , Colágeno Tipo IV/genética , Cápsula Glomerular/metabolismo , Cápsula Glomerular/patología , Membrana Basal Glomerular/patología , Exones
3.
BMC Res Notes ; 16(1): 54, 2023 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-37069662

RESUMEN

OBJECTIVE: A Delta-Notch signaling component, Notch1, is involved in the normal development and multiple disorders of the kidney. Although the increase in Notch1 signaling is crucial to these pathogeneses, the basal signaling level in 'healthy' mature kidneys is still unclear. To address this question, we used an artificial Notch1 receptor fused with Gal4/UAS components in addition to the Cre/loxP system and fluorescent proteins in mice. This transgenic reporter mouse system enabled labeling of past and ongoing Notch1 signaling with tdsRed or Cre recombinase, respectively. RESULTS: We confirmed that our transgenic reporter mouse system mimicked the previously reported Notch1 signaling pattern. Using this successful system, we infrequently observed cells with ongoing Notch1 signaling only in Bowman's capsule and tubules. We consider that Notch1 activation in several lines of disease model mice was pathologically significant itself.


Asunto(s)
Salud , Riñón , Receptor Notch1 , Transducción de Señal , Animales , Ratones , Riñón/citología , Riñón/metabolismo , Ligandos , Túbulos Renales Proximales/citología , Túbulos Renales Proximales/metabolismo , Células Epiteliales/metabolismo , Cápsula Glomerular/citología , Cápsula Glomerular/metabolismo , Sitios de Ligazón Microbiológica , Genes Reporteros , Receptor Notch1/genética , Receptor Notch1/metabolismo
4.
J Am Soc Nephrol ; 34(5): 737-750, 2023 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-36800545

RESUMEN

Podocytes and parietal epithelial cells (PECs) are among the few principal cell types within the kidney glomerulus, the former serving as a crucial constituent of the kidney filtration barrier and the latter representing a supporting epithelial layer that adorns the inner wall of Bowman's capsule. Podocytes and PECs share a circumscript developmental lineage that only begins to diverge during the S-shaped body stage of nephron formation-occurring immediately before the emergence of the fully mature nephron. These two cell types, therefore, share a highly conserved gene expression program, evidenced by recently discovered intermediate cell types occupying a distinct spatiotemporal gene expression zone between podocytes and PECs. In addition to their homeostatic functions, podocytes and PECs also have roles in kidney pathogenesis. Rapid podocyte loss in diseases, such as rapidly progressive GN and collapsing and cellular subtypes of FSGS, is closely allied with PEC proliferation and migration toward the capillary tuft, resulting in the formation of crescents and pseudocrescents. PECs are thought to contribute to disease progression and severity, and the interdependence between these two cell types during development and in various manifestations of kidney pathology is the primary focus of this review.


Asunto(s)
Glomeruloesclerosis Focal y Segmentaria , Podocitos , Humanos , Podocitos/metabolismo , Glomeruloesclerosis Focal y Segmentaria/patología , Glomérulos Renales/patología , Cápsula Glomerular/metabolismo , Cápsula Glomerular/patología , Células Epiteliales/metabolismo
5.
J Comp Pathol ; 197: 19-22, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-36089292

RESUMEN

A 12-year-old spayed Shiba dog with a nasal neuroendocrine carcinoma and multiple hepatic nodules was necropsied. Histologically, proliferated blast cells with a monolayer or multilayered structure were observed in the kidney. This blast cell proliferation extended from Bowman's capsule epithelium to the proximal tubule in approximately 3% of nephrons. Immunohistochemistry revealed that blast cells were positive for vimentin, Wilm's tumour protein 1 (WT1), paired box 2 (PAX2) and CD10, but negative for cytokeratin (CK) AE1/AE3, CK19, CAM5.2, synaptophysin and chromogranin A. On the basis of these findings, adenomatous hyperplasia of Bowman's capsule epithelium was diagnosed. Multiple yellowish‒white nodules (1-3 cm) were found in the liver and diagnosed as neuroendocrine carcinoma with metastases to the lungs, adrenal glands and pancreaticoduodenal lymph nodes.


Asunto(s)
Carcinoma Neuroendocrino , Enfermedades de los Perros , Neoplasias Hepáticas , Animales , Cápsula Glomerular/metabolismo , Cápsula Glomerular/patología , Carcinoma Neuroendocrino/veterinaria , Enfermedades de los Perros/patología , Perros , Epitelio/patología , Hiperplasia/patología , Hiperplasia/veterinaria , Neoplasias Hepáticas/veterinaria
6.
J Nephrol ; 35(4): 1193-1204, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35435603

RESUMEN

BACKGROUND AND OBJECTIVE: Lupus nephritis is one of the most severe manifestations of systemic lupus erythematosus. The clinical and prognostic significance of Bowman's capsule rupture in patients with lupus nephritis is unknown. METHODS: One hundred eighty patients with lupus nephritis were enrolled in the study and the integrity of Bowman's capsule was assessed. Both inflammatory and proliferative cells were detected by immunochemistry staining. The primary events of interest were end-stage renal disease and death. RESULTS: After retrospective analysis of the data, 52 (28.9%) patients were found to have Bowman's capsule rupture, which was accompanied by high levels of serum creatinine, 24 h urine protein, and Activity/Chronicity Index. Bowman's capsule rupture was correlated with the level of crescents, tubular atrophy, and interstitial fibrosis. The number of CD20+ cells was higher in the Bowman's capsule rupture ( +) group compared with the Bowman's capsule rupture (-) group, while no differences in other inflammatory cells were observed. In addition, the end stage renal disease-free survival in the Bowman's capsule rupture ( +) group was lower than in the Bowman's capsule rupture (-) group. Moreover, serum creatinine (HR 39.56, P < 0.001), Activity Index (HR 1.50, P < 0.05) as well as Bowman's capsule rupture (HR 1.09, P < 0.05) predicted end-stage renal disease progression. Notably, for patients with existing crescents, Bowman's capsule rupture increased the cumulative risk of end-stage renal disease. CONCLUSIONS: Bowman's capsule rupture is an important renal pathological lesion, which correlates with severe clinical manifestations, pathological changes, and poor prognosis in patients with lupus nephritis.


Asunto(s)
Fallo Renal Crónico , Nefritis Lúpica , Cápsula Glomerular/metabolismo , Cápsula Glomerular/patología , Creatinina , Femenino , Humanos , Riñón/patología , Fallo Renal Crónico/metabolismo , Nefritis Lúpica/diagnóstico , Nefritis Lúpica/patología , Masculino , Pronóstico , Estudios Retrospectivos
7.
Sci Rep ; 11(1): 1515, 2021 01 15.
Artículo en Inglés | MEDLINE | ID: mdl-33452384

RESUMEN

Diabetic nephropathy (DN) is accompanied by characteristic changes in the glomerulus, but little is known about the effect of diabetes on parietal epithelial cells (PECs). In this study, a descriptive analysis of PECs was undertaken in diabetic db/db mice and in diabetic patients. PEC hypertrophy was significantly more prominent in diabetic mice than in nondiabetic mice, and this was evident even at the early stage. Additionally, the number of vacuoles in PECs was markedly increased in diabetic mice, suggesting the presence of cellular injury in PECs in DN. Although rare, binuclear cells were observed in mice with early diabetes. In cultured PECs, a high glucose condition, compared with normal glucose condition, induced cellular hypertrophy and apoptosis. Flow cytometry showed that some PECs in the G0 phase reentered the cell cycle but got arrested in the S phase. Finally, in human diabetic subjects, hypertrophy and vacuolization were observed in the PECs. Our data showed that PECs undergo substantial changes in DN and may participate in rearrangement for differentiation into podocytes.


Asunto(s)
Diabetes Mellitus/fisiopatología , Podocitos/metabolismo , Adulto , Anciano , Animales , Cápsula Glomerular/metabolismo , Diferenciación Celular , Células Cultivadas , Diabetes Mellitus/metabolismo , Diabetes Mellitus Experimental/metabolismo , Nefropatías Diabéticas/metabolismo , Modelos Animales de Enfermedad , Células Epiteliales/metabolismo , Femenino , Humanos , Hipertrofia/fisiopatología , Glomérulos Renales/patología , Masculino , Ratones , Ratones Obesos , Persona de Mediana Edad , Podocitos/patología , Podocitos/fisiología
8.
BMC Nephrol ; 21(1): 402, 2020 09 18.
Artículo en Inglés | MEDLINE | ID: mdl-32948146

RESUMEN

BACKGROUND: Dipeptidyl peptidase-4 (DPP-4) is a serine protease that inhibits the degradation of glucagon-like peptide 1. DPP-4 inhibitors are used worldwide to treat type 2 diabetes mellitus and were recently shown to have pleiotropic effects such as anti-oxidant, anti-inflammatory, and anti-fibrotic actions. DPP-4 inhibitors improve albuminuria and renal injury including glomerular damage independent of its hypoglycemic effect. Although DPP-4 is mainly expressed in the kidney, the physiological function of DPP-4 remains unclear. METHODS: The localization of renal DPP-4 activity was determined in human renal biopsy specimens with glycyl-1-prolyl-4-methoxy-2-naphthylamide and the effects of a DPP-4 inhibitor were examined in human cultured podocyte. RESULTS: DPP-4 activity under normal conditions was observed in some Bowman's capsular epithelial cells and proximal tubules, but not in the glomerulus. DPP-4 activity was observed in crescent formation in anti-neutrophil myeloperoxidase cytoplasmic antigen antibody nephritis, nodular lesions in diabetic nephropathy, and some podocytes in focal segmental glomerulosclerosis. Notably, the DPP-4 inhibitor saxagliptin suppressed DPP-4 activity in podocytes and the proximal tubules. To assess the effect of DPP-4 inhibitor on podocytes, human cultured podocytes were injured by Adriamycin, which increased DPP-4 activity; this activity was dose-dependently suppressed by saxagliptin. Treatment with saxagliptin maintained the structure of synaptopodin and RhoA. Saxagliptin also improved the detachment of podocytes. CONCLUSIONS: DPP-4 activity induces degradation of synaptopodin and reduction of RhoA, resulting in destruction of the podocyte cytoskeleton. Saxagliptin may have pleiotropic effects to prevent podocyte injury.


Asunto(s)
Adamantano/análogos & derivados , Nefropatías Diabéticas/metabolismo , Dipéptidos/farmacología , Dipeptidil Peptidasa 4/metabolismo , Inhibidores de la Dipeptidil-Peptidasa IV/farmacología , Glomeruloesclerosis Focal y Segmentaria/metabolismo , Riñón/metabolismo , Nefritis/metabolismo , Podocitos/efectos de los fármacos , Adamantano/farmacología , Anticuerpos Anticitoplasma de Neutrófilos/inmunología , Cápsula Glomerular/metabolismo , Nefropatías Diabéticas/tratamiento farmacológico , Inhibidores de la Dipeptidil-Peptidasa IV/uso terapéutico , Doxorrubicina/farmacología , Femenino , Humanos , Técnicas In Vitro , Glomérulos Renales/metabolismo , Túbulos Renales Proximales/metabolismo , Masculino , Proteínas de Microfilamentos/efectos de los fármacos , Proteínas de Microfilamentos/metabolismo , Nefritis/inmunología , Podocitos/metabolismo , Proteína de Unión al GTP rhoA/efectos de los fármacos , Proteína de Unión al GTP rhoA/metabolismo
9.
Gene Expr Patterns ; 35: 119096, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-32027977

RESUMEN

Glomerular capillary formation is one of the fundamental mysteries in renal developmental biology. However, there are still debates on this issue, and its detailed formation process has not been clarified. To resolve this problem, we performed antibody staining with ultra-thick section on embryonic and postnatal mouse kidneys. We obtained the expression patterns of several genes that play an important role in the development of glomerular capillaries. We found that blood vessel of the fetal kidneys expanded through proliferation and sprouting. During the comma-stage and S-shaped stage, 3-4 capillaries began to bud and migrate into the glomerular cleft, forming a capillary bed in the Bowman's capsule. Then, the capillary bed expanded into mature glomerular capillary by intussusceptive angiogenesis. The afferent and efferent arterioles were formed through pruning. The distribution of VEGFA in the nephron epithelial cells but not only in podocytes, induced multiple capillaries sprouted into the glomerular cleft. And CXCR4 played an important role in the differentiation and expansion of capillary bed into glomerular capillary. Immunofluorescence performed with ultra-thick section allowed us to investigate the development of complex structure tissues systematically and comprehensively.


Asunto(s)
Capilares/embriología , Glomérulos Renales/embriología , Neovascularización Fisiológica , Animales , Cápsula Glomerular/embriología , Cápsula Glomerular/metabolismo , Capilares/metabolismo , Glomérulos Renales/citología , Glomérulos Renales/metabolismo , Ratones , Ratones Endogámicos C57BL , Receptores CXCR4/genética , Receptores CXCR4/metabolismo , Factor A de Crecimiento Endotelial Vascular/genética , Factor A de Crecimiento Endotelial Vascular/metabolismo
10.
Acta Histochem ; 121(4): 419-429, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-30904316

RESUMEN

Basement membranes consist of various proteins, the major ones being laminin and collagen type IV. Primary defects in these two proteins have been extensively associated with kidney pathologies. This study aimed to establish baseline information on the immunohistochemical distribution of laminin and collagen type IV, and to corelate these with the ultrastructure of basal laminae in the uriniferous tubules of the dromedary camel. Tissue samples were taken from the kidneys of eight adult female camels, and processed for immunohistochemical and ultrastructural investigations. Strong intensity of collagen type IV was observed within the basement membranes of Bowman's capsule. The thickness of the basal lamina of the parietal layer of Bowman's capsule varied extensively depending on the region of the renal corpuscle; the thicker areas were always associated with cuboidal epithelial cells. The glomerular basement membrane revealed strong immunostaining of laminin, whereas the mesangial matrix was strongly immunoreactive to collagen type IV. Abundant amount of laminin was found in the basement membranes of proximal convoluted tubules, thin limbs of the loop of Henle, and collecting ducts. Dense immunostainings of laminin and collagen type IV were observed in the medullary regions of uriniferous tubule, in which numerous projections extended from the basal laminae into the subjacent connective tissue. Overall, the present study revealed marked variations in the distribution of the basement membrane markers laminin and collagen type IV in the uriniferous tubules of camel kidney. The results have also shown difference in the thickness of basal laminae. This variation in thickness, however, was unlikely to be influenced by the amount of laminin and collagen type IV.


Asunto(s)
Membrana Basal/metabolismo , Riñón/metabolismo , Animales , Membrana Basal/ultraestructura , Cápsula Glomerular/metabolismo , Cápsula Glomerular/ultraestructura , Camelus , Colágeno Tipo IV/metabolismo , Femenino , Membrana Basal Glomerular/metabolismo , Membrana Basal Glomerular/ultraestructura , Inmunohistoquímica , Riñón/ultraestructura , Microscopía Electrónica de Transmisión
11.
Cell Tissue Res ; 369(1): 237-244, 2017 07.
Artículo en Inglés | MEDLINE | ID: mdl-28361304

RESUMEN

In normal glomeruli, parietal epithelial cells (PECs) line the inside of Bowman's capsule and form an inconspicuous sheet of flat epithelial cells in continuity with the proximal tubular epithelial cells (PTECs) at the urinary pole and with the podocytes at the vascular pole. PECs, PTECs and podocytes have a common mesenchymal origin and are the result of divergent differentiation during embryogenesis. Podocytes and PTECs are highly differentiated cells with well-established functions pertaining to the maintenance of the filtration barrier and transport, respectively. For PECs, no specific function other than a structural one has been known until recently. Possible important functions for PECs in the fate of the glomerulus in glomerular disease have now become apparent: (1) PECs may be involved in the replacement of lost podocytes; (2) PECs form the basis of extracapillary proliferative lesions and subsequent sclerosis in glomerular disease. In addition to the acknowledgement that PECs are crucial in glomerular disease, knowledge has been gained regarding the molecular processes driving the phenotypic changes and behavior of PECs. Understanding these molecular processes is important for the development of specific therapeutic approaches aimed at either stimulation of the regenerative function of PECs or inhibition of the pro-sclerotic action of PECs. In this review, we discuss recent advances pertaining to the role of PECs in glomerular regeneration and disease and address the major molecular processes involved.


Asunto(s)
Cápsula Glomerular , Enfermedades Renales , Túbulos Renales Proximales , Podocitos , Animales , Cápsula Glomerular/metabolismo , Cápsula Glomerular/patología , Cápsula Glomerular/fisiopatología , Humanos , Enfermedades Renales/metabolismo , Enfermedades Renales/patología , Enfermedades Renales/fisiopatología , Túbulos Renales Proximales/metabolismo , Túbulos Renales Proximales/patología , Túbulos Renales Proximales/fisiopatología , Podocitos/metabolismo , Podocitos/patología
12.
Histochem Cell Biol ; 148(1): 33-47, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-28315934

RESUMEN

Gas1 (Growth Arrest-Specific 1) is a pleiotropic protein with novel functions including anti-proliferative and proapoptotic activities. In the kidney, the expression of Gas1 has been described in mesangial cells. In this study, we described that renal parietal cells of Bowman's capsule (BC) and the distal nephron cells also express Gas1. The role of Gas1 in the kidney is not yet known. There is a subpopulation of progenitor cells in Bowman's capsule with self-renewal properties which can eventually differentiate into podocytes as a possible mechanism of regeneration in the early stages of diabetic nephropathy. We analyzed the expression of Gas1 in the parietal cells of Bowman's capsule in murine experimental diabetes. We found that diabetes reduced the expression of Gas1 and increased the expression of progenitor markers like NCAM, CD24, and SIX1/2, and mesenchymal markers like PAX2 in the Bowman's capsule. We also analyzed the expression of WT1 (a podocyte-specific marker) on BC and observed an increase in the number of WT1 positive cells in diabetes. In contrast, nephrin, another podocyte-specific protein, decreases its expression in the first week of diabetes in the glomerular tuft, which is gradually restored during the second and third weeks of diabetes. These results suggest that in diabetes the decrease of Gas1 promotes the activation of parietal progenitor cells of Bowman's capsule that might differentiate into podocytes and compensate their loss observed in this pathology.


Asunto(s)
Cápsula Glomerular/patología , Proteínas de Ciclo Celular/biosíntesis , Nefropatías Diabéticas/metabolismo , Células Epiteliales/metabolismo , Enfermedades Renales/metabolismo , Animales , Cápsula Glomerular/metabolismo , Nefropatías Diabéticas/patología , Células Epiteliales/patología , Proteínas Ligadas a GPI/biosíntesis , Enfermedades Renales/patología , Ratones
13.
Aging (Albany NY) ; 9(2): 524-546, 2017 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-28222042

RESUMEN

Advanced age portends a poorer prognosis in FSGS. To understand the impact of age on glomerular podocytes and parietal epithelial cells (PECs), experimental FSGS was induced in 3m-old mice (20-year old human age) and 27m-old mice (78-year old human age) by abruptly depleting podocytes with a cytopathic anti-podocyte antibody. Despite similar binding of the disease-inducing antibody, podocyte density was lower in aged FSGS mice compared to young FSGS mice. Activated PEC density was higher in aged versus young FSGS mice, as was the percentage of total activated PECs. Additionally, the percentage of glomeruli containing PECs with evidence of phosphorylated ERK and EMT was higher in aged FSGS mice. Extracellular matrix, measured by collagen IV and silver staining, was higher in aged FSGS mice along Bowman's capsule. However, collagen IV accumulation in the glomerular tufts alone and in glomeruli with both tuft and Bowman's capsule accumulation were similar in young FSGS and aged FSGS mice. Thus, the major difference in collagen IV staining in FSGS was along Bowman's capsule in aged mice. The significant differences in podocytes, PECs and extracellular matrix accumulation between young mice and old mice with FSGS might explain the differences in outcomes in FSGS based on age.


Asunto(s)
Envejecimiento/patología , Células Epiteliales/patología , Glomeruloesclerosis Focal y Segmentaria/patología , Glomérulos Renales/patología , Factores de Edad , Envejecimiento/metabolismo , Animales , Cápsula Glomerular/metabolismo , Cápsula Glomerular/patología , Colágeno/metabolismo , Modelos Animales de Enfermedad , Células Epiteliales/metabolismo , Matriz Extracelular/metabolismo , Matriz Extracelular/patología , Glomeruloesclerosis Focal y Segmentaria/metabolismo , Glomérulos Renales/metabolismo , Ratones , Fosforilación , Podocitos/metabolismo , Podocitos/patología
14.
FASEB J ; 31(1): 294-307, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-27825100

RESUMEN

Podocytes play a key role in diabetic nephropathy pathogenesis, but alteration of their metabolism remains unknown in human kidney. By using a conditionally differentiating human podocyte cell line, we addressed the functional and molecular changes in podocyte energetics during in vitro development or under high glucose conditions. In 5 mM glucose medium, we observed a stepwise activation of oxidative metabolism during cell differentiation that was characterized by peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α)-dependent stimulation of mitochondrial biogenesis and function, with concomitant reduction of the glycolytic enzyme content. Conversely, when podocytes were cultured in high glucose (20 mM), stepwise oxidative phosphorylation biogenesis was aborted, and a glycolytic switch occurred, with consecutive lactic acidosis. Expression of the master regulators of oxidative metabolism transcription factor A mitochondrial, PGC-1α, AMPK, and serine-threonine liver kinase B1 was altered by high glucose, as well as their downstream signaling networks. Focused transcriptomics revealed that myocyte-specific enhancer factor 2C (MEF2C) and myogenic factor 5 (MYF5) expression was inhibited by high glucose levels, and endoribonuclease-prepared small interfering RNA-mediated combined inhibition of those transcription factors phenocopied the glycolytic shift that was observed in high glucose conditions. Accordingly, a reduced expression of MEF2C, MYF5, and PGC-1α was found in kidney tissue sections that were obtained from patients with diabetic nephropathy. These findings obtained in human samples demonstrate that MEF2C-MYF5-dependent bioenergetic dedifferentiation occurs in podocytes that are confronted with a high-glucose milieu.-Imasawa, T., Obre, E., Bellance, N., Lavie, J., Imasawa, T., Rigothier, C., Delmas, Y., Combe, C., Lacombe, D., Benard, G., Claverol, S., Bonneu, M., Rossignol, R. High glucose repatterns human podocyte energy metabolism during differentiation and diabetic nephropathy.


Asunto(s)
Diferenciación Celular/efectos de los fármacos , Nefropatías Diabéticas/patología , Metabolismo Energético/efectos de los fármacos , Glucosa/farmacología , Podocitos/efectos de los fármacos , Cápsula Glomerular/metabolismo , Células Cultivadas , Metabolismo Energético/fisiología , Regulación de la Expresión Génica , Glucosa/administración & dosificación , Humanos , Oxidación-Reducción , Podocitos/fisiología
17.
Am J Physiol Renal Physiol ; 310(11): F1397-413, 2016 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-27076646

RESUMEN

The current studies used genetic fate mapping to prove that adult podocytes can be partially replenished following depletion. Inducible NPHS2-rtTA/tetO-Cre/RS-ZsGreen-R reporter mice were generated to permanently label podocytes with the ZsGreen reporter. Experimental focal segmental glomerulosclerosis (FSGS) was induced with a cytotoxic podocyte antibody. On FSGS day 7, immunostaining for the podocyte markers p57, synaptopodin, and podocin were markedly decreased by 44%, and this was accompanied by a decrease in ZsGreen fluorescence. The nuclear stain DAPI was absent in segments of reduced ZsGreen and podocyte marker staining, which is consistent with podocyte depletion. Staining for p57, synaptopodin, podocin, and DAPI increased at FSGS day 28 and was augmented by the ACE inhibitor enalapril, which is consistent with a partial replenishment of podocytes. In contrast, ZsGreen fluorescence did not return and remained significantly low at day 28, indicating replenishment was from a nonpodocyte origin. Despite administration of bromodeoxyuridine (BrdU) thrice weekly throughout the course of disease, BrdU staining was not detected in podocytes, which is consistent with an absence of proliferation. Although ZsGreen reporting was reduced in the tuft at FSGS day 28, labeled podocytes were detected along the Bowman's capsule in a subset of glomeruli, which is consistent with migration from the tuft. Moreover, more than half of the migrated podocytes coexpressed the parietal epithelial cell (PEC) proteins claudin-1, SSeCKS, and PAX8. These results show that although podocytes can be partially replenished following abrupt depletion, a process augmented by ACE inhibition, the source or sources are nonpodocyte in origin and are independent of proliferation. Furthermore, a subset of podocytes migrate to the Bowman's capsule and begin to coexpress PEC markers.


Asunto(s)
Glomeruloesclerosis Focal y Segmentaria/metabolismo , Glomérulos Renales/metabolismo , Podocitos/metabolismo , Animales , Cápsula Glomerular/metabolismo , Cápsula Glomerular/patología , Modelos Animales de Enfermedad , Glomeruloesclerosis Focal y Segmentaria/patología , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Glomérulos Renales/patología , Proteínas de la Membrana/metabolismo , Ratones , Proteínas de Microfilamentos/metabolismo , Podocitos/patología
18.
Am J Physiol Renal Physiol ; 309(2): F164-78, 2015 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-26017974

RESUMEN

Kidney aging is accompanied by characteristic changes in the glomerulus, but little is known about the effect of aging on glomerular parietal epithelial cells (PECs), nor if the characteristic glomerular changes in humans and rats also occur in very old mice. Accordingly, a descriptive analysis was undertaken in 27-mo-old C57B6 mice, considered advanced age. PEC density was significantly lower in older mice compared with young mice (aged 3 mo), and the decrease was more pronounced in juxtamedullary glomeruli compared with outer cortical glomeruli. In addition to segmental and global glomerulosclerosis in older mice, staining for matrix proteins collagen type IV and heparan sulfate proteoglycan were markedly increased in Bowman's capsules of older mouse glomeruli, consistent with increased extracellular matrix production by PECs. De novo staining for CD44, a marker of activated and profibrotic PECs, was significantly increased in aged glomeruli. CD44 staining was more pronounced in the juxtamedullary region and colocalized with phosphorylated ERK. Additionally, a subset of aged PECs de novo expressed the epithelial-to-mesenchymal transition markers α-smooth muscle and vimentin, with no changes in epithelial-to-mesenchymal transition markers E-cadherin and ß-catenin. The mural cell markers neural/glial antigen 2, PDGF receptor-ß, and CD146 as well as Notch 3 were also substantially increased in aged PECs. These data show that mice can be used to better understand the aging kidney and that PECs undergo substantial changes, especially in juxtamedullary glomeruli, that may participate in the overall decline in glomerular structure and function with advancing age.


Asunto(s)
Envejecimiento/patología , Células Epiteliales/patología , Glomérulos Renales/patología , Envejecimiento/metabolismo , Animales , Biomarcadores/metabolismo , Cápsula Glomerular/metabolismo , Células Epiteliales/metabolismo , Transición Epitelial-Mesenquimal , Proteínas de la Matriz Extracelular/metabolismo , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Femenino , Receptores de Hialuranos/metabolismo , Glomérulos Renales/metabolismo , Ratones Endogámicos C57BL , Pericitos/metabolismo , Fosforilación , Podocitos , Receptor Notch3 , Receptores Notch/metabolismo
19.
Lab Invest ; 95(3): 273-82, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25531564

RESUMEN

The metabolic and hemodynamic alterations in diabetes activate podocytes to increase extracellular matrix (ECM) production, leading to thickening of the glomerular basement membrane (GBM). We hypothesized that diabetes would activate parietal epithelial cells (PECs) in a similar manner and cause thickening of Bowman's capsules. Periodic acid Schiff staining of human kidney biopsies of 30 patients with diabetic nephropathy (DN) revealed a significantly thicker Bowman's capsule as compared with 20 non-diabetic controls. The average thickness was 4.55±0.21 µm in the group of patients with DN compared with 2.92±0.21 µm in the group of non-diabetic controls (P<0.001). Transmission electron microscopy confirmed this finding. In vitro, short-term exposure of human PECs to hyperglycemic conditions (30 mM glucose) advanced glycation end products (100 µg/ml) or transforming growth factor-ß1 (TGF-ß1; 5 ng/ml) increased the mRNA expression of collagen type I α-1, collagen type IV (all six α-chains), bamacan, nidogen 1, laminin α-1, and perlecan. Western blot and colorimetric collagen assays confirmed these results for collagen type IV at the protein level. The production and secretion of TGF-ß1 as a possible positive feedback loop was excluded as a mechanism for the autocrine activation of human PECs. To validate these findings in vivo, activation of the PECs was assessed by immunohistochemical staining for CD44 of 12 human biopsy cases with DN. Thickening of the Bowman's capsule showed strong association with CD44-positive PECs. In summary, metabolic alterations in diabetes activate PECs to increase the expression and secretion of Bowman's capsule proteins. This process may contribute to the thickening of the Bowman's capsule, similar to the thickening of the GBM that is driven by activated podocytes. These data may also imply that activated PECs contribute to ECM production once they migrate to the glomerular tuft, a process resulting in glomerular scaring, for example, in diabetic glomerulosclerosis.


Asunto(s)
Cápsula Glomerular/metabolismo , Colágeno/metabolismo , Nefropatías Diabéticas/metabolismo , Células Epiteliales/metabolismo , Glomérulos Renales/metabolismo , Adulto , Western Blotting , Cápsula Glomerular/patología , Células Cultivadas , Colágeno/genética , Cadena alfa 1 del Colágeno Tipo I , Nefropatías Diabéticas/genética , Nefropatías Diabéticas/patología , Células Epiteliales/patología , Células Epiteliales/ultraestructura , Femenino , Expresión Génica/efectos de los fármacos , Glucosa/farmacología , Productos Finales de Glicación Avanzada/farmacología , Humanos , Receptores de Hialuranos/metabolismo , Inmunohistoquímica , Glomérulos Renales/patología , Masculino , Microscopía Electrónica de Transmisión , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factor de Crecimiento Transformador beta1/metabolismo , Factor de Crecimiento Transformador beta1/farmacología
20.
J Membr Biol ; 247(8): 675-83, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24906870

RESUMEN

In kidney nephron, parietal epithelial cells line the Bowman's capsule and function as a permeability barrier for the glomerular filtrate. Bowman's capsule cells with proximal tubule epithelial morphology have been found. However, the effects of tubular metaplasia in Bowman's capsule on kidney function remain poorly understood. Sodium-glucose cotransporter 2 (SGLT2) plays a major role in reabsorption of glucose in the kidney and is expressed on brush border membrane (BBM) of epithelial cells in the early segment of the proximal tubule. We hypothesized that SGLT2 is expressed in tubularized Bowman's capsule and used our novel antibody to test this hypothesis. Immunohistochemical analysis was performed with our SGLT2 antibody on C57BL/6 mouse kidney prone to have tubularized Bowman's capsules. Cell membrane was examined with periodic acid-Schiff (PAS) stain. The results showed that SGLT2 was localized on BBM of the proximal tubules in young and adult mice. Bowman's capsules were lined mostly with normal brush border-less parietal epithelial cells in young mice, while they were almost completely covered with proximal tubule-like cells in adult mice. Regardless of age, SGLT2 was expressed on BBM of the tubularized Bowman's capsule but did not co-localize with nephrin in the glomerulus. SGLT2-expressing tubular cells expanded from the urinary pole toward the vascular pole of the Bowman's capsule. This study identified the localization of SGLT2 in the Bowman's capsule. Bowman's capsules with tubular metaplasia may acquire roles in reabsorption of filtered glucose and sodium.


Asunto(s)
Cápsula Glomerular/metabolismo , Membrana Celular/metabolismo , Epitelio/metabolismo , Túbulos Renales Proximales/metabolismo , Riñón/metabolismo , Microvellosidades/metabolismo , Transportador 2 de Sodio-Glucosa/metabolismo , Animales , Western Blotting , Cápsula Glomerular/citología , Glucosa/metabolismo , Técnicas para Inmunoenzimas , Riñón/citología , Túbulos Renales Proximales/citología , Masculino , Ratones , Ratones Endogámicos C57BL , Microscopía Confocal , Sodio/metabolismo
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