Yang Lu1, Takeo Nakanishi, Atsushi Hosomi, Hisakazu Komori, Ikumi Tamai. 1. Department of Membrane Transport and Biopharmaceutics, Faculty of Pharmaceutical Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan.
Abstract
OBJECTIVES: It has been reported that intestinal urate excretion is increased at chronic kidney disease (CKD) state. In this report, whether uremic toxins are involved in the upregulation of intestinal breast cancer resistance protein (BCRP), an intestinal urate exporter, was examined. METHODS: Uremic toxins that were increased at least 15-fold at CKD state were selected for investigation. Caco-2 cells were exposed to these uremic toxins at clinically relevant concentrations. mRNA was quantified by real-time PCR, and flow cytometry was utilized to measure BCRP protein and function in Caco-2 cells. Transcellular secretory transport of [(14) C]urate was determined utilizing Transwell studies after uremic toxin exposure. KEY FINDINGS: Indoxyl sulfate (IS) treatment alone resulted in ∼ 3-fold increase in BCRP mRNA in Caco-2 cells. Membrane protein expression of BCRP in Caco-2 cells also was increased by 1.8-fold after treatment with IS. Intracellular accumulation of pheophorbide A, a selective BCRP substrate, was decreased by 22% after IS treatment for 3 days. Consistent with these findings, transcellular secretory transport of urate across Caco-2 cell monolayers was increased by 22%. CONCLUSION: Intestinal urate secretion may be increased at CKD state partially by upregulation of intestinal BCRP by uremic toxins such as IS.
OBJECTIVES: It has been reported that intestinal urate excretion is increased at chronic kidney disease (CKD) state. In this report, whether uremic toxins are involved in the upregulation of intestinal breast cancer resistance protein (BCRP), an intestinal urate exporter, was examined. METHODS: Uremic toxins that were increased at least 15-fold at CKD state were selected for investigation. Caco-2 cells were exposed to these uremic toxins at clinically relevant concentrations. mRNA was quantified by real-time PCR, and flow cytometry was utilized to measure BCRP protein and function in Caco-2 cells. Transcellular secretory transport of [(14) C]urate was determined utilizing Transwell studies after uremic toxin exposure. KEY FINDINGS:Indoxyl sulfate (IS) treatment alone resulted in ∼ 3-fold increase in BCRP mRNA in Caco-2 cells. Membrane protein expression of BCRP in Caco-2 cells also was increased by 1.8-fold after treatment with IS. Intracellular accumulation of pheophorbide A, a selective BCRP substrate, was decreased by 22% after IS treatment for 3 days. Consistent with these findings, transcellular secretory transport of urate across Caco-2 cell monolayers was increased by 22%. CONCLUSION: Intestinal urate secretion may be increased at CKD state partially by upregulation of intestinal BCRP by uremic toxins such as IS.
Authors: Jennifer E Speer; Dulan B Gunasekara; Yuli Wang; John K Fallon; Peter J Attayek; Philip C Smith; Christopher E Sims; Nancy L Allbritton Journal: J Biol Eng Date: 2019-04-27 Impact factor: 4.355
Authors: Jitske Jansen; Katja Jansen; Ellen Neven; Ruben Poesen; Amr Othman; Alain van Mil; Joost Sluijter; Javier Sastre Torano; Esther A Zaal; Celia R Berkers; Diederik Esser; Harry J Wichers; Karin van Ede; Majorie van Duursen; Stéphane Burtey; Marianne C Verhaar; Björn Meijers; Rosalinde Masereeuw Journal: Proc Natl Acad Sci U S A Date: 2019-07-24 Impact factor: 11.205