Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The morphologic basis of proteinuria in experimental chronic serum sickness glomerulonephritis in rabbits was studied by light and electron microscopy using horseradish peroxidase (effective radius 30 A; mol. wt. 40,000) and ferritin (effective radius 60 A; mol. wt. 480,000) as protein tracers. It was found that more ferritin, but paradoxically, less horseradish peroxidase gained access to the urinary space. Observations made by electron microscopy appeared to indicate a decreased permeability of most part of the damaged glomerular capillary wall to both tracers. These results favor the interpretation that proteinuria in chronic serum sickness glomerulonephritis is the result of focal rather than diffuse increase in permeability of the glomerular capillary wall. Lesions of segments of the nephron other than the glomerular capillary wall, may contribute to the leakage of proteins to the urinary space.
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PMID:The morphologic basis of proteinuria in experimental chronic serum sickness glomerulonephritis. A light and electron microscopic study using horseradish peroxidase and ferritin as tracers. 66 50

Serum sickness nephritis was induced in male Fisher rats by immunization with egg albumin (EA). Correlations of subepithelial deposits (SD) with size and charge barriers of the glomerular filter were investigated using native (NF) and cationized (CF) ferritin as tracer probes. In proteinuric animals large numbers of NF molecules perfused from the abdominal aorta were observed to cross the glomerular basement membrane (GBM) and enter SD. The concentration of NF molecules was higher in GBM segments with SD than in GBM segments without SD, and the concentration of these molecules was higher within SD than in the intervening GBM. In contrast, CF clusters were fewer in number in the lamina rara externa (LRE) of GBM segments with SD than in the GBM segments without SD. CF particles could not be observed within SD, even in the areas of podocyte detachment. It is suggested that permeability in GBM segments with SD increases and that the development of proteinuria in this model can be attributed to alterations in both charge- and size-selective barriers to glomerular filtration.
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PMID:Influence of subepithelial deposits on permeability of the glomerular capillary wall in serum sickness nephritis in the rat. 180 51

Serum sickness nephritis was induced in Fisher rats by immunization with egg albumin (EA) and correlations between immune complex deposition, alterations of podocytes and development of proteinuria were analysed. Immunoelectron microscopy showed that EA, rat IgG and C3 were confined to the electron-dense deposits (Ds). From 3 weeks, when significant proteinuria had developed, the subepithelial region was filled with large numbers of Ds on the peripheral capillary wall as well as in the paramesangium. The loss of slit diaphragms and detachment of foot processes overlying Ds were observed and the escape of Ds into urinary space was frequently detected. Morphometric evaluation showed that the volume of subepithelial Ds and the number of the sites of podocytic detachment correlate significantly with the amount of proteinuria. In addition, the native ferritin injected via the abdominal aorta was seen in large amounts in the urinary space near the areas devoid of epithelial covering. The development of podocytic detachment was clearly coincident with the appearance of proteins with a larger molecular weight in urine. From these results, it is suggested that the loss of slit diaphragms and the detachment of podocytes resulting from the progressive accumulation of Ds will allow the leakage of proteins of larger molecular weight across the capillary wall. These podocytic lesions may be one of the main aetiologies for the development of heavy proteinuria in this model.
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PMID:Sequential ultrastructural podocytic lesions and development of proteinuria in serum sickness nephritis in the rat. 214 98

Immune complex deposits found on the subepithelial side of the glomerular basement membrane (GBM) are characteristic of membranous glomerulonephritis. In order to clarify the mechanism of subepithelial immune complex deposition, we investigated the manner of localization of preformed immune complexes (IC) composed of native ferritin (NF) and anti NF antibody (aNFab) in a 40-fold antigen great excess using the system of passive serum sickness nephritis of mice. The following results were obtained. (1) The ferritin particles in the GBM of animals given NF alone, as controls, were mainly restricted to the lamina rara interna (LRI) with very few penetrating the entire depth of the GBM. (2) In animals given the IC, greater numbers of ferritin particles were seen, in comparison with the control animals, not only in the lamina densa (LD) but also in the lamina rara externa (LRE). (3) Immunoelectron microscopy (IEM) demonstrated that each NF particle was accompanied by aNFab, which was found to be peroxidase positive material, throughout the GBM. (4) On the grounds that ICs were prepared in Ag great excess, it is suggested that ICs seen in the GBM are composed of a low avidity antibody with a low Ag/Ab ratio, probably Ag1Ab1. From these results, it is suggested that circulating ICs are necessary to give rise to IC deposition on the GBM and that NF and aNFab exist together as ICs throughout the GBM. We concluded that subepithelial IC deposits arise from the circulation, and that after GBM trapping, circulating small-sized IC can pass through the LD to reach the subepithelial side of GBM.
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PMID:[Studies on the mechanism of glomerular localization of immune complexes (1). Localization of preformed native ferritin immune complexes on the glomerular basement membrane in passive serum sickness nephritis of mice]. 258 31

In order to explore the pathogenic mechanism of proteinuria in glomerulonephritis, ultrastructural changes of the glomerular basement membrane were investigated in rats with chronic serum sickness induced by repeated intravenous injections of bovine serum albumin (experimental rats). Rats injected with saline served as controls. The animals were sacrificed and examined 13 weeks after treatment, when the mean urinary protein of experimental animals reached 206 mg/24h/100g body weight. Enhanced transcapillary passage of anionic ferritin was observed in experimental rats. Purified glomerular basement membranes of control and experimental rats were examined by electron microscopy after negative staining. The glomerular basement membrane of experimental rats had enlarged pores. The results suggest that an increase in the radius of glomerular pores may be responsible for proteinuria in glomerulonephritis.
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PMID:Changes in the molecular sieve of the glomerular basement membrane of rats with chronic serum sickness. 338 99

We studied the effect of PGE1 in pharmacologic doses on immune complex-induced glomerulonephritis produced by daily intraperitoneal injections of apoferritin. Mice received one of the following injection schedules: apoferritin 4 mg/day, apoferritin 4 mg/day plus PGE1 200 microgram twice daily, saline, or PGE1 200 microgram twice daily. Administration of apoferritin alone resulted in mesangial cell proliferation in all 14 mice with crescent formation in nine. Evidence of subepithelial and mesangial immune complex deposition and a significant increase in urine protein excretion was found. Treatment with PGE1 resulted in a mild increase in mesangial cells in six of 14 mice. No mice developed crescents on this regimen. In addition, proteinuria was prevented, and there was a marked diminution of immune complex deposition. Antiapoferritin antibody was detected in the sera of mice from both groups. No alteration in lymphocyte response to mitogen or in vitro PGE1 suppression of blastogenesis was detected. Our results indicate that PGE1 therapy alters immune complex glomerulonephritis in this model of murine chronic serum sickness by reducing glomerular immune complex deposition. However, no difference in specific or nonspecific immunologic responses was detected.
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PMID:Prostaglandin E1 therapy of murine chronic serum sickness. 699 40

Factor H is the major complement regulator in plasma. Abnormalities in factor H have been implicated in membranoproliferative glomerulonephritis in both humans and experimental animals. It has been shown that factor H on rodent platelets functions analogously to human erythrocyte complement receptor 1 in its role to traffic immune complexes to the mononuclear phagocyte system. C57BL/6 factor H-deficient mice (Cfh(-/-)) and wild-type (wt) controls were immunized daily for 5 wk with heterologous apoferritin to study the chronic serum sickness GN model. Immunizations were started in 6- to 8-wk-old mice, which was before the development of spontaneous membranoproliferative glomerulonephritis in some Cfh(-/-) animals. Glomerular deposition of IgG immune complexes in glomeruli was qualitatively and quantitatively increased in Cfh(-/-) mice compared with wt mice. Consistent with the increase in glomerular immune complexes and possibly because of alternative pathway complement activation, Cfh(-/-) mice had increased glomerular C3 deposition. Wt mice developed no glomerular pathology. In contrast, Cfh(-/-) mice developed diffuse proliferative GN with focal crescents and glomerulosclerosis. In addition, there was significantly increased expression of collagen IV, fibronectin, and laminin mRNA in Cfh(-/-) glomeruli. These data show a role for platelet-associated factor H to process immune complexes and limit their accumulation in glomeruli. Once deposited in glomeruli, excessive complement activation can lead to glomerular inflammation and the rapid development of a scarring phenotype.
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PMID:Complement factor h limits immune complex deposition and prevents inflammation and scarring in glomeruli of mice with chronic serum sickness. 1557 7

The complex balance between the pro-activating and regulatory influences of the complement system can affect the pathogenesis of immune complex-mediated glomerulonephritis (ICGN). Key complement regulatory proteins include decay accelerating factor (DAF) and CD59, which inhibit C3 activation and C5b-9 generation, respectively. Both are glycosylphosphatidylinositol-linked cell membrane proteins, which are widely distributed in humans and mice. Chronic serum sickness induced by daily immunization with horse spleen apoferritin over 6 weeks was used to induce ICGN in DAF-, CD59- and DAF/CD59-deficient mice, with wild-type littermate mice serving as controls. Both DAF and DAF/CD59-deficient mice had an increased incidence of GN relative to wild-type controls associated with significantly increased glomerular C3 deposition. Disease expression in CD59-deficient mice was no different than wild-type controls. DAF- and DAF/CD59-deficient mice also had increased monocyte chemoattractant protein-1 mRNA expression and glomerular infiltration with CD45(+) leukocytes. Our findings suggest that activation of C3 is strongly associated with experimental ICGN while downstream formation of C5b-9 is of lesser pathogenic importance in this model.
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PMID:Decay-accelerating factor but not CD59 limits experimental immune-complex glomerulonephritis. 1725 99

Complement factor H (Cfh) is a key plasma protein in humans and animals that serves to limit alternative pathway complement activation in plasma, as well as in local sites such as capillaries of the glomerulus and eye. It was shown that rodent Cfh on platelets is the functional analogue to human erythrocyte complement receptor 1 with a role that is distinct from plasma Cfh and that Cfh is also on cultured rodent podocytes. For investigation of the role of Cfh in the kidney, renal transplants were performed between wild-type (WT) and Cfh(-/-) C57BL/6 mice. For these studies, bilateral native nephrectomies were done so that renal function was dependent solely on the transplanted kidney. Chronic serum sickness was induced by active immunization with apoferritin. Diffuse proliferative glomerulonephritis (GN) occurred in WT kidneys that were transplanted into Cfh(-/-) recipients (n = 8) but not into WT recipients (n = 14), consistent with the importance of plasma Cfh to dictate outcome in this disease model. Relative to the WT recipients of WT kidneys, WT mice with Cfh(-/-) kidneys (n = 12) developed glomerular disease features, including increased albuminuria (82.8 +/- 7.0 versus 45.1 +/- 3.6 microg/mg creatinine; P < 0.001) and blood urea nitrogen levels (54.4 +/- 6.1 versus 44.2 +/- 3.7 mg/dl; P < 0.01). In addition, they had substantial glomerular capillary wall deposits of IgG and C3, which by electron microscopy were present in subendothelial and subepithelial immune deposits, whereas WT kidneys in WT hosts had almost exclusive mesangial deposits. The IgG deposits in Cfh(-/-) kidneys were adjacent to Cfh-deficient podocytes, whereas WT kidneys in a Cfh(-/-) host had podocyte-associated Cfh with absent IgG deposits. These data suggest that locally produced podocyte Cfh is important to process immune complexes in the subepithelial space, where it also limits complement activation. Just as in platelets, rodent podocytes seem to use Cfh as the functional surrogate for human complement receptor 1.
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PMID:Mouse podocyte complement factor H: the functional analog to human complement receptor 1. 1734 23

Complement receptor 1 (CR1) on human erythrocytes (Es) and complement factor H (CFH) on rodent platelets perform immune adherence, which is a function that allows the processing of immune complexes (ICs) bearing C3 by the mononuclear phagocyte system. Similar immune adherence occurs in the glomerular podocyte by CR1 in humans and CFH in rodents. As a model for human IC processing, we studied transgenic mice lacking CFH systemically but with human CR1 on Es. These CR1(hu)Tg/CFH(-/-) mice spontaneously developed proliferative glomerulonephritis, which was accelerated in a chronic serum sickness model by active immunization with heterologous apoferritin. ICs containing Ag, IgG and C3 bound to Es in CR1(hu)Tg/CFH(-/-) mice. In this setting, there was increased IC deposition in glomeruli, attributable to the presence of CR1 on Es, together with the absence of CFH on platelets and podocytes. In the absence of plasma CFH, the accumulated ICs activated complement, which led to spontaneous and chronic serum sickness-induced proliferative glomerulonephritis. These findings illustrate the complexities of complement-dependent IC processing by blood cells and in the glomerulus, and the importance of CFH as a plasma complement regulator.
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PMID:Abnormal immune complex processing and spontaneous glomerulonephritis in complement factor H-deficient mice with human complement receptor 1 on erythrocytes. 2070 29


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