Idiopathic membranous nephropathy (IMN) is an autoimmune disease of the kidney and a common cause of the nephrotic syndrome in adults. In addition to the weight gain, swelling, and risk of blood clots that accompany this disease, a substantial fraction of patients will develop progressive loss of kidney function and require dialysis or transplantation. Treatment for IMN often requires toxic immunosuppressive agents, which themselves cause health problems and risk of serious infection. The questions of who, when, and how long to treat have been difficult to answer due to an incomplete understanding of which patients will undergo remission from this disease on their own and who will progress to end-stage kidney disease. The recent identification by our laboratory of circulating antibodies that target a kidney protein, the phospholipase A2 receptor (PLA2R), in the majority of patients with IMN has not only allowed a redefinition of IMN based on these autoantibodies, but has also provided a potential mechanism by which to monitor the immunologic activity of the disease and guide these often-difficult treatment decisions. This proposal outlines our plans to use samples and data sets from the 150 patients with IMN to be enrolled in NEPTUNE (Nephrotic Syndrome Study Network) to better characterize the newly-recognized subgroups of IMN.
Aim 1 will classify each of the 150 IMN patients into two subgroups based on the presence of anti-PLA2R antibodies in the bloodstream or the presence of the PLA2R antigen within immune deposits of biopsy tissue already collected for this study. This will stratify the cohort into anti-PLA2R-associated or anti-PLA2R-negative disease. We will use the extensive NEPTUNE data sets of baseline demographic and clinical data, as well as the precise features seen in the biopsies of these patients, to find features that distinguish these two subtypes of IMN. A second portion of this aim will examine anti-PLA2R levels over time and use this information to follow immunological disease activity and thereby define 'immunological remission.' We will use the data from this aim to validate our hypothesis that immunological activity as reflected by the level of anti-PLA2R occurs prior to the clinical response, and may be a better measure of disease activity in general.
Aims 2 and 3 will harness the powerful gene transcription data sets available from the NEPTUNE cohort of IMN patients.
Aim 2 seeks to define anti-PLA2R-associated transcriptional networks in biopsy tissue in order to better understand molecular mechanisms of disease in IMN.
Aim 3 is designed to identify gene expression profiles that can functionally define and predict immunological remission, using gene expression data sets collected from circulating blood cells as well as the baseline kidney biopsy tissue. In aggregate, this project wil generate data that (1) defines and fully characterizes anti-PLA2R-associated IMN, (2) establishes the definition of immunological remission and its relationship to clinical remission, and (3) defines descriptive and predictive gene pathways that will greatly impact our future understanding of membranous nephropathy.

Public Health Relevance

Idiopathic membranous nephropathy (IMN) is a leading cause of the nephrotic syndrome in the adult population, and will ultimately lead to end-stage kidney disease in approximately one-third of affected individuals. New information about the molecular targets of this autoimmune disease can now allow precise characterization of the subtypes of this disease, which previously was not possible. Levels of a particular autoantibody circulating in the blood (anti-PLA2R), as well as large sets of information about changes in gene expression in kidney tissue and white blood cells, collected in the larger NEPTUNE project but measured and analyzed within the current study, will provide novel information that should lead to improved diagnosis and monitoring of IMN as well as a better understanding of the molecular and immunological basis of this disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
4R01DK097053-04
Application #
8997500
Study Section
Special Emphasis Panel (ZDK1-GRB-R (O4))
Program Officer
Flessner, Michael Francis
Project Start
2013-01-22
Project End
2017-12-31
Budget Start
2016-01-01
Budget End
2016-12-31
Support Year
4
Fiscal Year
2016
Total Cost
$314,888
Indirect Cost
$75,520
Name
Boston Medical Center
Department
Type
DUNS #
005492160
City
Boston
State
MA
Country
United States
Zip Code
02118
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Hoxha, Elion; Beck Jr, Laurence H; Wiech, Thorsten et al. (2017) An Indirect Immunofluorescence Method Facilitates Detection of Thrombospondin Type 1 Domain-Containing 7A-Specific Antibodies in Membranous Nephropathy. J Am Soc Nephrol 28:520-531
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Menn-Josephy, Hanni; Beck Jr, Laurence H (2015) Recurrent glomerular disease in the kidney allograft. Front Biosci (Elite Ed) 7:135-48
Ayalon, Rivka; Beck Jr, Laurence H (2015) Membranous nephropathy: not just a disease for adults. Pediatr Nephrol 30:31-9
Tomas, Nicola M; Beck Jr, Laurence H; Meyer-Schwesinger, Catherine et al. (2014) Thrombospondin type-1 domain-containing 7A in idiopathic membranous nephropathy. N Engl J Med 371:2277-2287

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