Cross-Talk Between Epithelial Sodium Channel and Basolateral K<sub>ir</sub>4.1/K<sub>ir</sub>5.1 Channels in the Cortical Collecting Duct
October 22, 2020 | 05:00 PM - 07:00 PM
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Cross-Talk Between Epithelial Sodium Channel and Basolateral Kir4.1/Kir5.1 Channels in the Cortical Collecting Duct
- Molecular Insights in Ion, Acid, and Water Handling
October 22, 2020 | Location: Simulive
Abstract Time: 05:00 PM - 07:00 PM
Category: Fluid, Electrolyte, and Acid-Base Disorders
- 901 Fluid, Electrolyte, and Acid-Base Disorders: Basic
- Palygin, Oleg, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Isaeva, Elena, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Levchenko, Vladislav, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Denton, Jerod S., Vanderbilt University Medical Center, Nashville, Tennessee, United States
- Staruschenko, Alexander, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
Oleg Palygin, PhD
My research is focused on ion channels and ion transport in the kidney, and I apply multiple sophisticated approaches to address unresolved questions of physiological mechanisms responsible for the regulation of renal function in health and disease. Today, a greater understanding has been achieved of the cellular and molecular mechanisms underlying renal function processes and how these processes may become disordered in chronic kidney disease states such as hypertension, polycystic kidney, and diabetes mellitus. My laboratory is interested in several aspects of the kidney: its ability to control and regulate body electrolytes, its vulnerability to genetically related mutations, oxidative stress, albuminuria, and the role that transport potassium channels, protease-activated receptors, and the purines like ATP play in these processes.
Jerod S. Denton,
The growing body of evidence suggest that inwardly rectifying K+ (Kir) channels located on the basolateral membrane of epithelial cells in the distal nephron play a crucial role in K+ handling and blood pressure control, making these channels attractive targets for the treatment of hypertension. The purpose of the present study was to determine how the inhibition of basolateral Kir4.1 homomeric or Kir4.1/Kir5.1 heteromeric K+ channels affects ENaC-mediated Na+ transport in the cortical collecting duct (CCD) principal cells.
Electrophysiological approaches were used to test the effect of fluoxetine, amitriptyline, and recently developed Kir4.1 inhibitor, VU0134992, on the activity of Kir4.1, Kir4.1/Kir5.1, and ENaC. Channel activity was recorded in CHO cells transfected with respective channel subunits, cultured polarized epithelial mCCDc11 cells, and native freshly isolated rat and human CCD tubules. To test the effect of pharmacological Kir4.1/Kir5.1 inhibition on electrolyte homeostasis in vivo, Dahl salt-sensitive rats were injected with amitriptyline (15 mg/kg/day).
We found that inhibition of Kir4.1/Kir5.1, but not Kir4.1 channel, substantially suppresses both amiloride-sensitive ISC in mCCDc11 cells and single-channel ENaC activity in principal cells of rat and human CCD tubules. Furthermore, we demonstrate that i.p. injection of Kir4.1/Kir5.1 antagonist for three days leads to a significant drop in plasma K+ level, triggering sodium excretion, and diuresis.
These data uncover a putative mechanism underlying a renal control of blood electrolytes mediated by Kir4.1/Kir5.1 and introduce a new molecular target for the treatment of salt-sensitive hypertension.
- NIDDK Support