β<sub>3</sub>-Adrenergic Receptor: Possible New Drug Targets for the Treatment of Autosomal Dominant Polycystic Kidney Disease
November 08, 2019 | 10:00 AM - 12:00 PM
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β3-Adrenergic Receptor: Possible New Drug Targets for the Treatment of Autosomal Dominant Polycystic Kidney Disease
Cystic Kidney Diseases: Clinical/Translational
November 08, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Genetic Diseases of the Kidneys
- 1001 Genetic Diseases of the Kidneys: Cystic
- Schena, Giorgia, Yale University School of Medicine, New Haven, Connecticut, United States
- Gerbino, Andrea, University of Bari "Aldo Moro", Bari, Italy
- Carmosino, Monica, University of Basilicata, Italy, Potenza, Italy
- Caplan, Michael J., Yale University School of Medicine, New Haven, Connecticut, United States
Michael J. Caplan,
Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a genetic condition caused by mutations in either Polycystin 1 or Polycystin 2 genes and characterized by the formation of fluid filled cysts in the renal parenchyma. Elevations of intracellular cAMP are a major driver of cyst growth. Inhibition of cAMP accumulation in vasopressin-sensitive nephron segments currently constitutes the only approved therapy for ADPKD. Interestingly, sympathetic nerve activity is elevated in patients with chronic kidney disease and this over-activity has been implicated in cystogenesis. Since β3-adrenoreceptors (β3-ARs) are expressed in multiple nephron segments we wished to characterize their signaling pathway in ADPKD and their potential role in its pathogenesis.
Murine cell lines heterozygous (Pkd1+/-) or homozygous (Pkd1-/-) for a deletion in Pkd1 gene were stably transfected with β3-AR, then seeded in 3D matrix and stimulated with Mirabegron, a selective β3-AR agonist. Cyst size and number were measured using ImageJ. cAMP levels in treated cells were measured via Fluorescence Resonance Energy Transfer (FRET). β3-AR expression was studied via WB on total kidney lysates from an ADPKD mouse model (Pkd1fl/fl; Pax8rtTA; TetO-Cre). Mice were treated with either β3-AR antagonist SR59230A (4mg/kg/day) for 4 weeks or saline. Finally animals were sacrificed and kidney parameters measured.
We found that, upon treatment with Mirabegron, Pkd1-/-+β3-AR cells form larger and more numerous cysts than untransfected Pkd1-/- cells. FRET analysis confirmed that this effect is associated with a significant increase in cAMP levels elicited by β3-AR activation. Using our ADPKD mouse model we found that renal β3-AR expression is up-regulated in cystic animals versus healty littermates. Most importantly, treatment of these mice with SR59230A leads to improved kidney/body weight ratios and Blood Urea Nitrogen levels in the treated animals versus controls.
Our in vitro data indicate that modulating the activity of β3-AR has a direct effect on cystogenesis. Our in vivo data further suggest that β3-ARs are potentially interesting therapeutic targets in the treatment of ADPKD in that antagonizing β3-AR activity may reduce cAMP accumulation and thus cyst growth in both vasopressin-sensitive and insensitive nephron segments.
- NIDDK Support