N-sulfation of heparan sulfate is critical for syndecan-4 mediated podocyte cell-matrix interactions.

Previous research has shown that podocytes unable to assemble heparan sulfate on cell surface proteoglycan core proteins have compromised cell-matrix interactions. This report further explores the role of N-sulfation of intact heparan chains in podocyte-matrix interactions. For the purposes of this study, a murine model in which the enzyme N-deacetylase/N-sulfotransferase 1 (NDST1) was specifically deleted in podocytes and immortalized podocyte cell lines lacking NDST1 were developed and used to explore the effects of such a mutation on podocyte behavior in vitro. NDST1 is a bifunctional enzyme, ultimately responsible for N-sulfation of heparan glycosaminoglycans produced by cells. Immunostaining of glomeruli from mice whose podocytes were null for Ndst1 (Ndst1−/−) showed a disrupted pattern of localization for the cell surface proteoglycan, syndecan-4, and for α-actinin-4 compared with controls. The pattern of immunostaining for synaptopodin and nephrin did not show as significant alterations. In vitro s...