The sodium-bicarbonate cotransporter NBCe2 (slc4a5) expressed in human renal proximal tubules shows increased apical expression under high-salt conditions.

The electrogenic sodium bicarbonate cotransporter (NBCe2) is encoded by SLC4A5, variants of which have been associated with salt sensitivity of blood pressure, which affects 25% of the adult population. NBCe2 is thought to mediate sodium bicarbonate cotransport primarily in the renal collecting duct, but NBCe2 mRNA is also found in the rodent renal proximal tubule (RPT). The protein expression or function of NBCe2 has not been demonstrated in the human RPT.

Exosomal transfer from human renal proximal tubule cells to distal tubule and collecting duct cells.

Objectives: Exosomes are 50-90nm extracellular membrane particles that may mediate trans-cellular communication between cells and tissues. We have reported that human urinary exosomes contain miRNA that are biomarkers for salt sensitivity and inverse salt sensitivity of blood pressure. This study examines exosomal transfer between cultured human renal proximal tubule cells (RPTCs) and from RPTCs to human distal tubule and collecting duct cells.