Expression Of SLC4A11, Claudin 4 And Other Cell Membrane Transporters In The Mammalian Renal Medulla And Their Physiological Implications

Abstract

The kidneys play a vital role in maintaining solute homeostasis in mammals. One way the kidneys can regulate solute concentrations is through the urine concentrating mechanism. Although advancements have been made to elucidate the general functions of different kidney regions, the medulla is not as well understood. The goal of this study is to examine the architecture and expression of specific proteins in the mammalian medulla. A tight junction protein called claudin-4 has been shown to be expressed in rat medullary collecting ducts, thin ascending limbs (TALs) of Henle’s Loops, and potentially in aquaporin-1 (AQP1) negative descending thin limbs (DTLs) of Henle’s Loops. Meanwhile, the transporter protein SLC4A11 has been found to be expressed in primarily the DTLs and potentially in other structures in both mice and rat kidneys. Additionally, three-dimensional reconstruction of the tubules in the pig medullary region has been performed. These findings not only provide us with several potential biomarkers that can be used to study the mammalian renal medulla, but also provide some insight into the different transport processes that occur in the renal medulla.