Autoantibodies against thrombospondin type 1 domain–containing 7A induce membranous nephropathy
Nicola M. Tomas, … , Catherine Meyer-Schwesinger, Rolf A.K. Stahl
Nicola M. Tomas, … , Catherine Meyer-Schwesinger, Rolf A.K. Stahl
Published May 23, 2016
Citation Information: J Clin Invest. 2016;126(7):2519-2532. https://doi.org/10.1172/JCI85265.
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Research Article Nephrology

Autoantibodies against thrombospondin type 1 domain–containing 7A induce membranous nephropathy

Abstract

Membranous nephropathy (MN) is the most common cause of nephrotic syndrome in adults, and one-third of patients develop end-stage renal disease (ESRD). Circulating autoantibodies against the podocyte surface antigens phospholipase A2 receptor 1 (PLA2R1) and the recently identified thrombospondin type 1 domain–containing 7A (THSD7A) are assumed to cause the disease in the majority of patients. The pathogenicity of these antibodies, however, has not been directly proven. Here, we have reported the analysis and characterization of a male patient with THSD7A-associated MN who progressed to ESRD and subsequently underwent renal transplantation. MN rapidly recurred after transplantation. Enhanced staining for THSD7A was observed in the kidney allograft, and detectable anti-THSD7A antibodies were present in the serum before and after transplantation, suggesting that these antibodies induced a recurrence of MN in the renal transplant. In contrast to PLA2R1, THSD7A was expressed on both human and murine podocytes, enabling the evaluation of whether anti-THSD7A antibodies cause MN in mice. We demonstrated that human anti-THSD7A antibodies specifically bind to murine THSD7A on podocyte foot processes, induce proteinuria, and initiate a histopathological pattern that is typical of MN. Furthermore, anti-THSD7A antibodies induced marked cytoskeletal rearrangement in primary murine glomerular epithelial cells as well as in human embryonic kidney 293 cells. Our findings support a causative role of anti-THSD7A antibodies in the development of MN.

Authors

Nicola M. Tomas, Elion Hoxha, Anna T. Reinicke, Lars Fester, Udo Helmchen, Jens Gerth, Friederike Bachmann, Klemens Budde, Friedrich Koch-Nolte, Gunther Zahner, Gabriele Rune, Gerard Lambeau, Catherine Meyer-Schwesinger, Rolf A.K. Stahl

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Figure 8

Anti-THSD7A antibodies induce cell detachment and cytoskeletal rearrangement in THSD7A-expressing HEK293 cells.

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Anti-THSD7A antibodies induce cell detachment and cytoskeletal rearrange...
(A) Western blot analysis shows reactivity of a specific anti-THSD7A antibody in HEK293 cells that were transfected with THSD7A cDNA or empty vector. (B and C) Quantification of detached cells by measurement of total protein concentration in cell pellets after centrifugation of cell culture supernatants following a 60-minute incubation with (B) anti-THSD7A antibody–containing or control serum (results are from at least 5 independent experiments with 2 anti-THSD7 antibody–positive sera, 5 anti-PLA2R1 antibody–positive sera, 5 sera with no antibodies against THSD7A or PLA2R1, and 1 control serum) or with (C) affinity-purified anti-THSD7A antibodies, depleted serum, and affinity-purified IgG from a healthy individual (results are from 5 independent experiments with antibodies purified from 1 patient, the corresponding depleted serum, and purified control IgG). Data indicate the fold change in protein content in the cell culture supernatant in comparison with the cells that were transfected with empty vector and treated with serum from a healthy donor (B) or with purified control IgG (C). Error bars indicate the mean ± SEM. ***P < 0.001, by 1-way ANOVA with Bonferroni’s post test; statistical significance is shown for all conditions versus THSD7A-transfected cells that were treated with anti-THSD7A antibody–containing serum (B) or affinity-purified anti-THSD7A antibodies (C). (D) Immunofluorescence staining for huIgG and F-actin (phalloidin) in empty vector– and THSD7A-transfected HEK293 cells after a 30-minute exposure to anti-THSD7A antibody–containing serum or control serum. Arrows show accentuated cortical F-actin rings; asterisks indicate detaching cells. Scale bars: 20 μm.