Expression of SLC4A11 protein in mouse and rat medulla: a candidate transporter involved in outer medullary ammonia recycling

• Published in: Physiological reports 2019-05, Vol.7 (10), p.e14089-n/a
• Main Authors: Gee, Michael T., Kurtz, Ira, Pannabecker, Thomas L.
• Format: Article
• Language: English
• Subjects: Ammonia - metabolism; Animals; Anion Transport Proteins - metabolism; Antiporters - metabolism; Aquaporin 1 - metabolism; Cellular Physiology; Countercurrent mechanism; H+ transport; Kidney Medulla - metabolism; Loop of Henle - metabolism; Membrane Physiology; Membrane Transport Proteins - metabolism; Mice, Inbred ICR; Original Research; Rats, Wistar; Renal Elimination; Renal Physiology; Renal Reabsorption; Species Specificity; Symporters - metabolism; thin limb of Henle's loop; Urea Transporters; vasa recta
• ISSN: 2051-817X
• DOI: 10.14814/phy2.14089

SLC4A11 is a multifunctional membrane transporter involved with H+ transport, NH3 and alkaline pH stimulated H+ transport, and water transport. The role of SLC4A11 in the kidney is not well understood. A prior study has shown that in murine kidney, SLC4A11/LacZ staining is primarily in the long‐looped descending thin limb (DTL) as determined by colocalization with aquaporin 1 (AQP1), a protein that is expressed in some, but not all, descending thin limb segments. Using a previously characterized polyclonal antibody, we demonstrate the selective expression of SLC4A11 in the upper DTLs (which are AQP1‐positive) in the outer medulla and inner medulla with little or no expression in the lower DTLs (which are AQP‐1‐null). SLC4A11 also colocalized with AQP1 and the urea transporter UT‐B in the mouse descending vasa recta, but was absent in mouse and rat ascending vasa recta. Mouse, but not rat, outer medullary collecting duct cells also labeled for SLC4A11. Our results are compatible with the hypothesis that in the inner stripe of the outer medulla, SLC4A11 plays a role in the countercurrent transport of ammonia absorbed from the outer medullary thick ascending limb and secreted into the long‐looped DTLs. SLC4A11 can potentially modulate the rate of ammonia transport in the mouse outer medullary collecting duct. Our data suggest functionally unique SLC4A11 pathways in mouse and rat and complement previous studies of DTL Na+, urea and water permeability indicating that the upper and lower DTLs of long‐looped nephrons are functionally distinct. SLC4A11 is a multifunctional membrane transporter involved in H+ transport, NH3 and alkaline pH stimulated H+ transport, and water transport. In the renal medulla, SLC4A11 is expressed in the upper DTLs (which are AQP1‐positive) with little or no expression in the lower DTLs (which are AQP‐1‐null). This expression pattern is compatible with the hypothesis that in the inner stripe of the outer medulla, SLC4A11 plays a role in the countercurrent transport of ammonia absorbed from the outer medullary thick ascending limb and secreted into the long‐looped DTLs.