Kidney disease is huge worldwide health problem that is becoming increasingly prevalent. Primary glomerular disease, both acquired and genetic, represents a significant proportion of these cases, due in part to the incidence of diabetic nephropathy. We are interested in understanding the makeup of the glomerular filtration barrier and how it becomes damaged and leaky to plasma proteins. Our focus over the last decade has been to investigate the composition and function of the glomerular basement membrane (GBM), a specialized extracellular matrix that is an integral component of the filtration barrier. The GBM contains laminin, collagen IV, nidogen, and the heparan sulfate proteoglycan agrin. Recent analysis of mice lacking the laminin 22 chain, the only laminin 2 chain present in normal GBM, suggests that the GBM itself serves as the primary barrier to albumin, as the affected mice exhibit proteinuria even when podocytes have apparently normal foot process and slit diaphragm architecture. In addition, in vivo GBM permeability studies show that the mutant GBM is more permeable to ferritin than is control. Recently, mutations in human LAMB2 have been shown to cause kidney disease. Null mutations cause Pierson syndrome (congenital nephrotic syndrome with ocular and nervous system abnormalities), whereas some missense mutations cause isolated congenital nephrotic syndrome. The focus of this proposal is to understand the mechanism whereby these mutations in human LAMB2 cause glomerular filtration defects. To accomplish this, we will 1) engineer human LAMB2 missense mutations into mice so that behavior of the mutant proteins, disease progression, and glomerular ultrastructure can be followed in detail;2) use biochemical methods to investigate the ability of the mutant forms to assemble and polymerize in vitro;3) test the hypothesis that a reduction in the amount of total laminin in the GBM in the absence of 22 contributes to filtration barrier defects;4) assay the ability of laminin heterotrimers and agrin to diffuse in the plane of the GBM;5) determine the half-lives of laminin 22 and agrin in the GBM. Together, the results of these studies will provide important new insights into laminin and basement membrane biology and lead to a better understanding of the mechanism of glomerular filtration and the etiology of glomerular disease. Project Narrative/Relevance Kidney disease is huge worldwide health problem that is becoming increasingly prevalent. Primary glomerular disease represents a significant proportion of these cases, due in part to the increasing incidence of diabetic nephropathy and obesity. The goal of this proposal is to provide a better understanding the makeup of the glomerular filtration barrier and how it becomes damaged and leaky to plasma proteins, with a focus on laminin 22, an important component of the glomerular basement membrane.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK078314-03
Application #
7778224
Study Section
Special Emphasis Panel (ZRG1-RUS-B (12))
Program Officer
Ketchum, Christian J
Project Start
2008-03-01
Project End
2012-02-29
Budget Start
2010-03-01
Budget End
2011-02-28
Support Year
3
Fiscal Year
2010
Total Cost
$319,770
Indirect Cost
Name
Washington University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Funk, Steven D; Lin, Meei-Hua; Miner, Jeffrey H (2018) Alport syndrome and Pierson syndrome: Diseases of the glomerular basement membrane. Matrix Biol 71-72:250-261
Funk, Steven D; Bayer, Raymond H; Malone, Andrew F et al. (2018) Pathogenicity of a Human Laminin ?2 Mutation Revealed in Models of Alport Syndrome. J Am Soc Nephrol 29:949-960
Fissell, William H; Miner, Jeffrey H (2018) What Is the Glomerular Ultrafiltration Barrier? J Am Soc Nephrol 29:2262-2264
Luo, Wentian; Olaru, Florina; Miner, Jeffrey H et al. (2018) Alternative Pathway Is Essential for Glomerular Complement Activation and Proteinuria in a Mouse Model of Membranous Nephropathy. Front Immunol 9:1433
Lin, Meei-Hua; Miller, Joseph B; Kikkawa, Yamato et al. (2018) Laminin-521 Protein Therapy for Glomerular Basement Membrane and Podocyte Abnormalities in a Model of Pierson Syndrome. J Am Soc Nephrol 29:1426-1436
Suleiman, Hani Y; Roth, Robyn; Jain, Sanjay et al. (2017) Injury-induced actin cytoskeleton reorganization in podocytes revealed by super-resolution microscopy. JCI Insight 2:
Dutta, Rajesh K; Kondeti, Vinay K; Sharma, Isha et al. (2017) Beneficial Effects of Myo-Inositol Oxygenase Deficiency in Cisplatin-Induced AKI. J Am Soc Nephrol 28:1421-1436
Beckerman, Pazit; Bi-Karchin, Jing; Park, Ae Seo Deok et al. (2017) Transgenic expression of human APOL1 risk variants in podocytes induces kidney disease in mice. Nat Med 23:429-438
Tsuji, Kenji; Suleiman, Hani; Miner, Jeffrey H et al. (2017) Ultrastructural Characterization of the Glomerulopathy in Alport Mice by Helium Ion Scanning Microscopy (HIM). Sci Rep 7:11696
Lawrence, Marlon G; Altenburg, Michael K; Sanford, Ryan et al. (2017) Permeation of macromolecules into the renal glomerular basement membrane and capture by the tubules. Proc Natl Acad Sci U S A 114:2958-2963

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