51
|
Asanuma K, Akiba-Takagi M, Kodama F, Asao R, Nagai Y, Lydia A, Fukuda H, Tanaka E, Shibata T, Takahara H, Hidaka T, Asanuma E, Kominami E, Ueno T, Tomino Y. Dendrin location in podocytes is associated with disease progression in animal and human glomerulopathy. Am J Nephrol 2011; 33:537-49. [PMID: 21606645 DOI: 10.1159/000327995] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 03/30/2011] [Indexed: 12/19/2022]
Abstract
BACKGROUND Adriamycin (ADR) nephrosis in mice has been extensively studied and has enabled a greater understanding of the processes underlying the progression of renal injury. Dendrin is a novel component of the slit diaphragm with proapoptotic signaling properties, and it accumulates in the podocyte nucleus in response to glomerular injury in mice. The present study re-evaluated chronic progressive nephropathy in ADR mice and the localization of dendrin in mice and in human glomerulopathy. METHODS To investigate the localization of dendrin, a mouse model of nephrosis and glomerulosclerosis was used, in which ADR was injected once. WT-1-positive cells and apoptotic cells were counted in vivo and in vitro. To check the expression of dendrin in ADR mice, immunostaining and Western blot were performed. A survey of dendrin staining was performed on human kidney biopsy specimens. RESULTS The injection of ADR induced proteinuria, podocyte loss and glomerulosclerosis. It also caused the relocation of dendrin from the slit diaphragm to the podocyte nucleus. We demonstrated the location of dendrin to podocyte nuclei in several cases of human glomerulopathy. The mean occurrence of dendrin-positive nucleus per glomerulus increased in several cases of human glomerulopathy. CONCLUSIONS These findings suggest that the relocation of dendrin to the podocyte nuclei is useful as a novel marker of podocyte injury in human glomerulopathy.
Collapse
Affiliation(s)
- Katsuhiko Asanuma
- Division of Nephrology, Department of Internal Medicine, Juntendo University Faculty of Medicine, Tokyo, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
52
|
Zhang SY, Audard V, Lang P, Sahali D. [Molecular mechanisms in nephrotic syndrome: role of c-mip in podocyte dysfunctions]. Med Sci (Paris) 2010; 26:592-6. [PMID: 20619160 DOI: 10.1051/medsci/2010266-7592] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
|
53
|
Murakami A, Oshiro H, Kanzaki S, Yamaguchi A, Yamanaka S, Furuya M, Miura S, Kanno H, Nagashima Y, Aoki I, Nagahama K. A novel method for isolating podocytes using magnetic activated cell sorting. Nephrol Dial Transplant 2010; 25:3884-90. [PMID: 20530496 DOI: 10.1093/ndt/gfq323] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND A large body of accumulated data has now revealed that podocytes play a major role in the development of proteinuria. However, the mechanisms of podocyte injury, leading to foot process effacement and proteinuria, are still unclear partly due to the current lack of an appropriate strategy for preparing podocytes. In this study, we have developed a novel method of rapid isolation of podocytes from mice using magnetic activated cell sorting with an anti-nephrin antibody. METHODS After endothelial cell depletion using anti-CD31 antibody, nephrin-positive cells were prepared from mouse kidneys using magnetic activated cell sorting with polyclonal rabbit anti-nephrin antibody. Purity of the positively sorted cells was determined by confocal microscopy and fluorescence-activated cell sorting (FACS) analysis. Expression profiles of podocyte-specific molecules in the sorted fractions were characterized by qualitative PCR and immunoblot analysis. RESULTS Nephrin-positive cells, isolated from mouse kidneys within 6 h, showed dual positivity for synaptopodin and rabbit IgG on confocal microscopy. FACS analysis revealed that the purity of the positively sorted fractions was ∼75%. The nephrin-positive cells sorted by this approach showed a significantly higher expression of podocyte-specific molecules compared with nephrin-negative fractions. CONCLUSIONS These data strongly suggest that our novel method for isolating podocytes has great utility for various downstream applications such as genomic analysis, proteomics and transcriptomics to elucidate molecular profiling of podocyte biology in vivo compared with conventional methods as our approach requires only several hours to complete and no tissue culture.
Collapse
Affiliation(s)
- Ayumi Murakami
- Department of Pathology, Yokohama City University School of Medicine 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
54
|
Ma H, Togawa A, Soda K, Zhang J, Lee S, Ma M, Yu Z, Ardito T, Czyzyk J, Diggs L, Joly D, Hatakeyama S, Kawahara E, Holzman L, Guan JL, Ishibe S. Inhibition of podocyte FAK protects against proteinuria and foot process effacement. J Am Soc Nephrol 2010; 21:1145-56. [PMID: 20522532 DOI: 10.1681/asn.2009090991] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase that plays a critical role in cell motility. Movement and retraction of podocyte foot processes, which accompany podocyte injury, suggest focal adhesion disassembly. To understand better the mechanisms by which podocyte foot process effacement leads to proteinuria and kidney failure, we studied the function of FAK in podocytes. In murine models, glomerular injury led to activation of podocyte FAK, followed by proteinuria and foot process effacement. Both podocyte-specific deletion of FAK and pharmacologic inactivation of FAK abrogated the proteinuria and foot process effacement induced by glomerular injury. In vitro, podocytes isolated from conditional FAK knockout mice demonstrated reduced spreading and migration; pharmacologic inactivation of FAK had similar effects on wild-type podocytes. In conclusion, FAK activation regulates podocyte foot process effacement, suggesting that pharmacologic inhibition of this signaling cascade may have therapeutic potential in the setting of glomerular injury.
Collapse
Affiliation(s)
- Hong Ma
- Departments of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
55
|
Machida H, Ito S, Hirose T, Takeshita F, Oshiro H, Nakamura T, Mori M, Inayama Y, Yan K, Kobayashi N, Yokota S. Expression of Toll-like receptor 9 in renal podocytes in childhood-onset active and inactive lupus nephritis. Nephrol Dial Transplant 2010; 25:2530-537. [PMID: 20181802 DOI: 10.1093/ndt/gfq058] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Childhood-onset systemic lupus erythematosus (SLE) is frequently complicated with lupus nephritis (LN), which is characterized by the deposition of DNA-containing immune complex to the glomerulus. Toll-like receptor 9 (TLR9), capable of recognizing the microbially derived CpG oligonucleotide, plays a crucial role in the innate immunity. TLR9 is also assumed to be related to the aetiology of SLE in the recognition of anti-DNA antibody-containing immune complex, but this remains controversial. We conducted a study to elucidate the association between TLR9 and LN in childhood-onset SLE. METHODS We compared the expression and localization of TLR9 and the slit membrane-related protein in the biopsied kidney sample by immunostaining in four children with active or inactive LN. We also evaluated their laboratory findings, such as anti-DNA antibody, complement and proteinuria at biopsy, to assess the correlation to the findings of the immunostaining. RESULTS TLR9 is not expressed in a normal control kidney. However, TLR9 develops in podocytes only in active LN but disappears in remission. Meanwhile, the slit membrane-related proteins such as nephrin, podocin and synaptopodin in podocytes express clearly and uniformly in remission, but their expression is markedly diminished in active LN, which results in podocyte injury. When TLR9 is expressed in podocytes, all the patients simultaneously showed hypocomplementaemia, high titre of anti-double-stranded DNA (dsDNA) antibody and proteinuria. CONCLUSION Injured podocytes in active LN express TLR9. This expression could be associated with proteinuria and increased anti-dsDNA antibody. This is the first report indicating that TLR9 is involved in the aetiology of LN and that it may play some role in podocyte injury.
Collapse
|
56
|
Ponticelli C. Recurrence of focal segmental glomerular sclerosis (FSGS) after renal transplantation. Nephrol Dial Transplant 2009; 25:25-31. [PMID: 19875378 DOI: 10.1093/ndt/gfp538] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
|
57
|
Trivedi S, Zeier M, Reiser J. Role of podocytes in lupus nephritis. Nephrol Dial Transplant 2009; 24:3607-12. [DOI: 10.1093/ndt/gfp427] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
58
|
Sarav M, Wang Y, Hack BK, Chang A, Jensen M, Bao L, Quigg RJ. Renal FcRn reclaims albumin but facilitates elimination of IgG. J Am Soc Nephrol 2009; 20:1941-52. [PMID: 19661163 DOI: 10.1681/asn.2008090976] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The widely distributed neonatal Fc receptor (FcRn) contributes to maintaining serum levels of albumin and IgG in adults. In the kidney, FcRn is expressed on the podocytes and the brush border of the proximal tubular epithelium. Here, we evaluated the role of renal FcRn in albumin and IgG metabolism. Compared with wild-type controls, FcRn(-/-) mice had a lower t((1/2)) for albumin (28.7 versus 39.9 h) and IgG (29.5 versus 66.1 h). Renal loss of albumin could account for the former, suggested by the progressive development of hypoalbuminemia in wild-type mice transplanted with FcRn-deficient kidneys. Furthermore, serum albumin levels returned to normal in FcRn(-/-) recipients of wild-type kidneys after removing the native FcRn-deficient kidneys. In contrast, renal loss could not account for the enhanced elimination of IgG in FcRn(-/-) mice. These mice had minimal urinary excretion of native and labeled IgG, which increased to wild-type levels in FcRn(-/-) recipients of a single FcRn-sufficient kidney (t((1/2)) of IgG was 21.7 h). Taken together, these data suggest that renal FcRn reclaims albumin, thereby maintaining the serum concentration of albumin, but facilitates the loss of IgG from plasma protein pools.
Collapse
Affiliation(s)
- Menaka Sarav
- Section of Nephrology, Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | | | | | | | | | | | | |
Collapse
|
59
|
Hussain S, Romio L, Saleem M, Mathieson P, Serrano M, Moscat J, Diaz-Meco M, Scambler P, Koziell A. Nephrin deficiency activates NF-kappaB and promotes glomerular injury. J Am Soc Nephrol 2009; 20:1733-43. [PMID: 19497968 DOI: 10.1681/asn.2008111219] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Increasing evidence implicates activation of NF-kappaB in a variety of glomerular diseases, but the mechanisms involved are unknown. Here, upregulation of NF-kappaB in the podocytes of transgenic mice resulted in glomerulosclerosis and proteinuria. Absence of the podocyte protein nephrin resulted in NF-kappaB activation, suggesting that nephrin negatively regulates the NF-kappaB pathway. Signal transduction assays supported a functional relationship between nephrin and NF-kappaB and suggested the involvement of atypical protein kinase C (aPKCzeta/lambda/iota) as an intermediary. We propose that disruption of the slit diaphragm leads to activation of NF-kappaB; subsequent upregulation of NF-kappaB-driven genes results in glomerular damage mediated by NF-kappaB-dependent pathways. In summary, nephrin may normally limit NF-kappaB activity in the podocyte, suggesting a mechanism by which it might discourage the evolution of glomerular disease.
Collapse
Affiliation(s)
- Sagair Hussain
- Molecular Medicine Unit, Institute of Child Health, London, UK.
| | | | | | | | | | | | | | | | | |
Collapse
|
60
|
Audard V, Lang P, Sahali D. [Minimal change nephrotic syndrome : new insights into disease pathogenesis]. Med Sci (Paris) 2009; 24:853-8. [PMID: 18950582 DOI: 10.1051/medsci/20082410853] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Idiopathic nephrotic syndrome is the most frequent glomerular disease in children. While genetic analyses have provided new insights into disease pathogenesis through the discovery of several podocyte genes mutated in distinct forms of inherited nephrotic syndrome, the molecular bases of minimal change nephrotic syndrome (MCNS) and focal and segmental glomerulosclerosis (FSGS) with relapse remain unclear. Although immune cell disorders, which may involve both innate and adaptive immunity, appear to play a role in the pathogenesis of steroid sensitive MCNS, the mechanisms by which they induce podocyte dysfunction remain unresolved. It was postulated that podocyte injury results from a circulating factor secreted by abnormal T cells, but the possibility that bipolarity of the disease results from a functional disorder shared by both cell systems is not excluded. MCNS relapses are associated with an activation of the immune system, including an expansion of T and B cell compartments and production of growth factors as well as many cytokines. Dysfunction of T cells is supported by three main findings: (1) inhibition of a type III hypersensitivity reaction ; (2) defects in immunoglobulin switch ; (3) unclassical T helper polarization resulting from transcriptional interference between Th1 and Th2 transcriptional factors.
Collapse
Affiliation(s)
- Vincent Audard
- Inserm U 841, Institut Mondor de Recherche Biomédicale (IMRB), Département génétique , Equipe 21
| | | | | |
Collapse
|
61
|
Garin EH, Diaz LN, Mu W, Wasserfall C, Araya C, Segal M, Johnson RJ. Urinary CD80 excretion increases in idiopathic minimal-change disease. J Am Soc Nephrol 2008; 20:260-6. [PMID: 19056875 DOI: 10.1681/asn.2007080836] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
CD80 is expressed on all antigen-presenting cells and is present on podocytes in a number of experimental models of nephrotic syndrome. We tested whether urinary soluble CD80 increased with idiopathic minimal-change disease (MCD). We collected urine and serum samples from patients with MCD in relapse and in remission, patients with nephrotic syndrome resulting from other glomerular diseases (FSGS, membranoproliferative glomerulonephritis, IgA nephropathy, and membranous nephropathy), patients with systemic lupus erythematosus, and normal control subjects. Urinary concentrations of soluble CD80 in patients with relapsed MCD were significantly higher compared with those observed in patients with MCD in remission, other glomerular diseases, and systemic lupus erythematosus with and without proteinuria and healthy control subjects. Urinary concentrations of soluble CTLA-4, which is a negative regulator of CD80, were not statistically different in patients with relapsed MCD compared with those in remission. The urinary soluble CD80/CTLA-4 ratio was >100-fold higher in patients with relapsed MCD compared with those in remission (P < 0.008). In contrast, serum concentrations of soluble CD80 and CTLA-4 did not distinguish patients with MCD in relapse and in remission. In conclusion, urinary soluble CD80 is elevated in idiopathic MCD, which could be relevant to both diagnosis and pathogenesis.
Collapse
Affiliation(s)
- Eduardo H Garin
- Division of Pediatric Nephrology, University of Florida, Gainesville, FL 32610, USA.
| | | | | | | | | | | | | |
Collapse
|
62
|
Tipping PG. Are podocytes passive or provocative in proteinuric glomerular pathology? J Am Soc Nephrol 2008; 19:651-3. [PMID: 18322155 DOI: 10.1681/asn.2008020156] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
|
63
|
Banas MC, Banas B, Hudkins KL, Wietecha TA, Iyoda M, Bock E, Hauser P, Pippin JW, Shankland SJ, Smith KD, Stoelcker B, Liu G, Gröne HJ, Krämer BK, Alpers CE. TLR4 links podocytes with the innate immune system to mediate glomerular injury. J Am Soc Nephrol 2008; 19:704-13. [PMID: 18256364 DOI: 10.1681/asn.2007040395] [Citation(s) in RCA: 165] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Toll-like receptors (TLR) classically recognize pathogen-associated danger signals but are also activated via endogenous ligands. For evaluation of their role in inflammatory kidney disease, the function of TLR was analyzed in two mouse models of cryoglobulinemic membranoproliferative glomerulonephritis (MPGN; mice transgenic for thymic stromal lymphopoietin [TSLP], with or without deletion of the Fcgamma receptor IIb). Expression of TLR1 through 9 and TLR11 mRNA was detectable in whole kidneys and in isolated glomeruli of wild-type mice, with TLR3 and TLR4 having the highest absolute levels of expression. TLR1, 2, and 4 were increased in TSLP transgenic mice and even higher in TSLP transgenic FcgammaRIIb-deficient mice. TLR5 through 9 and 11 were upregulated to similar degrees in TSLP transgenic and TSLP transgenic FcgammaRIIb-deficient mice. Immunohistochemical studies of nephritic glomeruli localized TLR4 protein to podocytes. Cultured podocytes also expressed TLR4, and stimulation with TLR4-specific ligands resulted in a marked induction of chemokines; this was reduced by specific knockdown of TLR4 with siRNA. Fibrinogen, a potential endogenous TLR4 ligand, was shown to induce a similar profile of chemokines. In conclusion, it was demonstrated that TLR4 is constitutively expressed by podocytes and is upregulated in MPGN, where it may mediate glomerular injury by modulating expression of chemokines; therefore, TLR4 may link podocytes with the innate immune system to mediate MPGN triggered by the deposition of immune complexes.
Collapse
Affiliation(s)
- Miriam C Banas
- Department of Internal Medicine II, University of Regensburg, 93042 Regensburg, Germany.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
64
|
Faulhaber JR, Nelson PJ. Virus-induced cellular immune mechanisms of injury to the kidney. Clin J Am Soc Nephrol 2007; 2 Suppl 1:S2-5. [PMID: 17699506 DOI: 10.2215/cjn.00020107] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Cellular immune systems play an important role in determining renal outcomes in virus-induced kidney diseases. Highlighted briefly are five different locations along the development of adaptive immune responses to viral infection that may promote injury to the renal parenchyma and the loss of renal function. This may occur because adaptive immune cells directly target infected renal parenchymal cells or because the kidney becomes a bystander organ of adaptive immune cell-mediated injury. Examples from recent studies are provided to illustrate how this may lead to clinically relevant renal disease.
Collapse
Affiliation(s)
- Jason R Faulhaber
- Division of Infectious Diseases, New York University School of Medicine, New York, New York 10016, USA
| | | |
Collapse
|
65
|
Lai KW, Wei CL, Tan LK, Tan PH, Chiang GSC, Lee CGL, Jordan SC, Yap HK. Overexpression of interleukin-13 induces minimal-change-like nephropathy in rats. J Am Soc Nephrol 2007; 18:1476-85. [PMID: 17429054 DOI: 10.1681/asn.2006070710] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
IL-13 has been implicated in the pathogenesis of minimal-change nephrotic syndrome. This study aimed to investigate the role of IL-13 on the development of proteinuria and expression of podocyte-related genes that are associated with nephrotic syndrome. IL-13 was overexpressed in Wistar rats through transfection of a mammalian expression vector cloned with the rat IL-13 gene, into the quadriceps by in vivo electroporation. Serum IL-13, albumin, cholesterol, and creatinine and urine albumin were measured serially. Kidneys were harvested after day 70 for histology and electron microscopy. Glomerular gene expression of nephrin, podocin, dystroglycan, B7-1, and IL-13 receptor subunits were examined using real-time PCR with hybridization probes and expressed as an index against beta-actin. Protein expression of these molecules was determined by immunofluorescence staining. The IL-13-transfected rats (n = 41) showed significant albuminuria, hypoalbuminemia, and hypercholesterolemia when compared with control rats (n = 17). No significant histologic changes were seen in glomeruli of IL-13-transfected rats. However, electron microscopy showed up to 80% of podocyte foot process fusion. Glomerular gene expression was significantly upregulated for B7-1, IL-4Ralpha, and IL-13Ralpha2 but downregulated for nephrin, podocin, and dystroglycan. Immunofluorescence staining intensity was reduced for nephrin, podocin, and dystroglycan but increased for B7-1 and IL-4Ralpha in IL-13-transfected rats compared with controls. In conclusion, these results suggest that IL-13 overexpression in the rat could lead to podocyte injury with downregulation of nephrin, podocin, and dystroglycan and a concurrent upregulation of B7-1 in the glomeruli, inducing a minimal change-like nephropathy that is characterized by increased proteinuria, hypoalbuminemia, hypercholesterolemia, and fusion of podocyte foot processes.
Collapse
Affiliation(s)
- Kin-Wai Lai
- Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | | | | | | | | | | | | | | |
Collapse
|
66
|
Mintern JD, Klemm EJ, Wagner M, Paquet ME, Napier MD, Kim YM, Koszinowski UH, Ploegh HL. Viral interference with B7-1 costimulation: a new role for murine cytomegalovirus fc receptor-1. THE JOURNAL OF IMMUNOLOGY 2007; 177:8422-31. [PMID: 17142739 DOI: 10.4049/jimmunol.177.12.8422] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Murine CMV (MCMV), a beta-herpesvirus, infects dendritic cells (DC) and impairs their function. The underlying events are poorly described. In this study, we identify MCMV m138 as the viral gene responsible for promoting the rapid disappearance of the costimulatory molecule B7-1 (CD80) from the cell surface of DC. This was unexpected, as m138 was previously identified as fcr-1, a putative virus-encoded FcR. m138 impaired the ability of DC to activate CD8+ T cells. Biochemical analysis and immunocytochemistry showed that m138 targets B7-1 in the secretory pathway and reroutes it to lysosomal associated membrane glycoprotein-1+ compartments. These results show a novel function for m138 in MCMV infection and identify the first viral protein to target B7-1.
Collapse
Affiliation(s)
- Justine D Mintern
- Department of Pathology, Harvard Medical School, Boston, MA 02115. USA
| | | | | | | | | | | | | | | |
Collapse
|
67
|
Gu L, Ni Z, Qian J, Tomino Y. Pravastatin Inhibits Carboxymethyllysine-Induced Monocyte Chemoattractant Protein 1 Expression in Podocytes via Prevention of Signalling Events. ACTA ACUST UNITED AC 2007; 106:e1-10. [PMID: 17347584 DOI: 10.1159/000100498] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2006] [Accepted: 12/14/2006] [Indexed: 11/19/2022]
Abstract
BACKGROUND Up-regulation of local monocyte chemoattractant protein 1 (MCP-1) production is involved in glomerular damage through macrophage recruitment and activation in diabetic nephropathy. Advanced glycation end-products induced chemokine production in cultured mesangial cells and podocytes. Statins prevented recruitment of macrophages to the glomeruli, suggesting that statins may have the ability of anti-inflammation. In the present studies, we investigated the effects of pravastatin in the carboxymethyllysine (CML)-induced MCP-1 expression in mouse differentiated podocytes. METHODS MCP-1 gene and protein expressions were examined using RT-PCR and ELISA. Dichlorofluorescein-sensitive intracellular reactive oxygen species (ROS) generation was measured by confocal microscopy. Activation of extracellular signal-regulated kinase (ERK), nuclear factor (NF) kappaB and Sp1 were studied using Western blotting and immunocytochemistry. RESULTS MCP-1 was induced by CML in a time- and dose-dependent manner. CML-induced MCP-1 mRNA and protein production were inhibited by 0.1 or 1 mM pravastatin. CML rapidly generated intracellular ROS in podocytes. Pravastatin did not have any ability of blocking ROS generation. Phosphorylated ERK was found in podocytes incubated with CML and was prevented by pravastatin in a dose-dependent manner. Both Western blotting and immunocytochemistry results suggested that pretreatment of podocytes with pravastatin prevented the CML-induced NF-kappaB and Sp1 translocation. CONCLUSION These results suggest that pravastatin prevents CML to induce MCP-1 expression in podocytes via modulation of the intracellular ERK/NF-kappaB and Sp1 signalling pathway.
Collapse
Affiliation(s)
- Leyi Gu
- Renal Division, Renji Hospital, Shanghai Jiaotong University, School of Medicine, Shanghai, China.
| | | | | | | |
Collapse
|
68
|
Peters I, Tossidou I, Achenbach J, Woroniecki R, Mengel M, Park JK, Paschy M, de Groot K, Haller H, Schiffer M. IGF-Binding Protein-3 Modulates TGF-β/BMP-Signaling in Glomerular Podocytes. J Am Soc Nephrol 2006; 17:1644-56. [PMID: 16672319 DOI: 10.1681/asn.2005111209] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Podocyte apoptosis initiates progressive glomerulosclerosis in TGF-beta1 transgenic and CD2AP-knockout (CD2AP-/-) mice. It was previously shown that in both mouse models, activation of the TGF-beta pathway is the key event during development of podocyte apoptosis. Furthermore, CD2AP is an important modifier of TGF-beta-induced survival signaling via activation of the phosphoinositol 3-kinase/AKT signaling pathway. This article presents IGF-binding protein-3 (IGFBP-3) as a new modulator of apoptosis and survival signaling in glomerular podocytes. High expression of IGFBP-3 protein in the urine of diseased CD2AP-/- mice was discovered, and IGFBP-3 expression in glomerular podocytes and parietal cells was detected. IGFBP-3 can induce changes in podocyte actin cytoskeleton, leads to apoptosis in cultured murine podocytes, and can enhance TGF-beta1-induced apoptosis in vitro. For studying this process on a molecular level, proapoptotic p38 mitogen-activated protein kinase pathways and antiapoptotic phosphoinositol 3-kinase/AKT pathways were examined in cultured murine podocytes. It was found that IGFBP-3 increments the level of TGF-beta1-induced phosphorylated p38 mitogen-activated protein kinase and decreases the phosphorylation of antiapoptotic AKT. This effect is specific for the co-stimulation of IGFBP-3 with TGF-beta1 because a combination of IGFBP-3 with bone morphogenic protein-7 (BMP-7), another member of the TGF-beta superfamily, results in apoptosis opposing signaling effects with a strong increase of phosphorylated AKT and subsequent functional effects. These results demonstrate that the IGF/IGFBP axis plays an important role in the development of podocyte apoptosis by modulation of TGF-beta and BMP-7-induced pro- and antiapoptotic signals.
Collapse
Affiliation(s)
- Imke Peters
- Division of Nephrology, Department of Medicine, Hannover Medical School, Carl-Neuberg-Strasse 1, Hannover, 30625 Germany, and Division of Pediatric Nephrology, Children's Hospital at Montefiore, Bronx, NY, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
69
|
Abstract
The discovery of new functions for the original B7 family members, together with the identification of additional B7 and CD28 family members, have revealed new ways in which the B7:CD28 family regulates T cell activation and tolerance. B7-1/B7-2:CD28 interactions not only promote initial T cell activation but also regulate self-tolerance by supporting CD4+CD25+ T regulatory cell homeostasis. CTLA-4 can exert its inhibitory effects in both B7-1/B7-2 dependent and independent fashions. B7-1 and B7-2 can signal bidirectionally by engaging CD28 and CTLA-4 on T cells and by delivering signals into B7-expressing cells. The five new B7 family members, ICOS ligand, PD-L1 (B7-H1), PD-L2 (B7-DC), B7-H3, and B7-H4 (B7x/B7-S1) are expressed on professional antigen-presenting cells as well as on cells within nonlymphoid organs, providing new means for regulating T cell activation and tolerance in peripheral tissues. The new CD28 families members, ICOS, PD-1, and BTLA, are inducibly expressed on T cells, and they have important roles in regulating previously activated T cells. PD-1 and BTLA also are expressed on B cells and may have broader immunoregulatory functions. The ICOS:ICOSL pathway appears to be particularly important for stimulating effector T cell responses and T cell-dependent B cell responses, but it also has an important role in regulating T cell tolerance. In addition, the PD-1:PD-L1/PD-L2 pathway plays a critical role in regulating T cell activation and tolerance. In this review, we revisit the roles of the B7:CD28 family members in regulating immune responses, and we discuss their therapeutic potential.
Collapse
Affiliation(s)
- Rebecca J Greenwald
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
| | | | | |
Collapse
|
70
|
Vincenti F, Ghiggeri GM. New insights into the pathogenesis and the therapy of recurrent focal glomerulosclerosis. Am J Transplant 2005; 5:1179-85. [PMID: 15888021 DOI: 10.1111/j.1600-6143.2005.00968.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Recurrent focal glomerulosclerosis (FSGS) in renal allografts has remained a frustrating and enigmatic disease. Recent studies on gene mutations encoding podocin and other components of the slit-diaphragm in patients with native kidney nephrotic syndrome have underscored the heterogenecity of the idiopathic form of FSGS. While familial FSGS rarely recurs following transplantation, the sporadic variety of FSGS is associated with a 30% recurrence rate. The patients with the sporadic variety of FSGS who have homozygous or complex heterozygous podocin mutations have a low recurrence rate. In the other patients with sporadic FSGS, a more complex and likely multifactorial etiology accounts for the recurrence of FSGS. The role of CD80 expression on podocytes is intriguing but requires confirmation in kidney biopsies of patients with recurrent FSGS. Recent findings on podocin genomics, the permeability factor and CD80 expression may ultimately lead to a better understanding of recurrent FSGS as well as a more effective approach to its prevention and treatment.
Collapse
Affiliation(s)
- Flavio Vincenti
- Kidney Transplant Service, University of California, San Francisco, USA.
| | | |
Collapse
|