Apical serine protease activity is necessary for assembly of a high-resistance renal collecting duct epithelium

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Abstract AIM: We hypothesized that the serine protease prostasin is necessary for differentiation of a high resistance renal collecting duct epithelium governed by glucocorticoid. METHODS: Postnatal rat kidney and adult human kidney was used to study expression and localization of prostasin. The murine collecting duct cell line (M-1) was cultured in snapwell inserts to investigate the significance of prostasin for development of transepithelial electrical resistance (TER). RESULTS: In rat kidney cortex and medulla, prostasin mRNA and protein increased significantly between birth and weaning (day 21) and was detected in collecting ducts. Immunoreactive prostasin was associated with collecting ducts and loops of Henle in human kidney. In rat, adrenalectomy at day 10 had no effect on prostasin mRNA level in kidney at day 20. Cultured M-1 cells exhibited parallel increases in prostasin mRNA, protein and TER 5 days after seeding. Apical addition of the serine protease inhibitor aprotinin to M-1 cell cultures inhibited development of TER and led to aberrant localization of E-cadherin. This effect was mimicked by the protease inhibitor nafamostat. Apical addition of phospholipase C to cleave GPI anchors released prostasin to the medium and attenuated development of TER with time of culture. Disruption of lipid rafts by methyl-beta-cyclodextrin attenuated development of TER in M-1 cells. Omission of dexamethasone impaired development of TER in M-1 cells, while prostasin protein abundance and E-cadherin distribution did not change. CONCLUSION: Apical, GPI-anchored, lipid raft-associated serine protease activity, compatible with prostasin, is necessary for development of a high-resistance collecting duct epithelium.
JournalActa Physiologica (Print Edition)
Issue number4
Pages (from-to)347-359
Publication statusPublished - 2010