Nephronectin Regulates Mesangial Cell Adhesion and Behavior in Glomeruli

作者:Zimmerman Susan E; Hiremath Chitkale; Tsunezumi Jun; Yang Zhufeng; Finney Bronwyn; Marciano Denise K*
来源:Journal of the American Society of Nephrology, 2018, 29(4): 1128-1140.
DOI:10.1681/ASN.2017070752

摘要

A critical aspect of kidney function occurs at the glomerulus, the capillary network that filters the blood. The glomerular basement membrane (GBM) is a key component of filtration, yet our understanding of GBM interactions with mesangial cells, specialized pericytes that provide structural stability to glomeruli, is limited. We investigated the role of nephronectin (Npnt), a GBM component and known ligand of alpha 8 beta 1 integrin. Immunolocalization and in situ hybridization studies in kidneys of adult mice revealed that nephronectin is produced by podocytes and deposited into the GBM. Conditional deletion of Npnt from nephron progenitors caused a pronounced increase in mesangial cell number and mesangial sclerosis. Nephronectin colocalized with alpha 8 beta 1 integrin to novel, specialized adhesion structures that occurred at sites of mesangial cell protrusion at the base of the capillary loops. Absence of nephronectin disrupted these adhesion structures, leading to mislocalization of alpha 8 beta 1. Podocyte-specific deletion of Npnt also led to mesangial sclerosis in mice. These results demonstrate a novel role for nephronectin and alpha 8 beta 1 integrin in a newly described adhesion complex and begin to uncover themolecular interactions between the GBM and mesangial cells, which govern mesangial cell behavior and may have a role in pathologic states.

  • 出版日期2018-4