Soluble Uric Acid Increased The Expression Of PDZK1 And ABCG2 In Human Intestinal Cell Lines

ObjectiveThe most common reason generating hyperuricemia is the obstacle of urate excretion,as verified by current researches.Besides the kidney,intestine is known as the most important organ involved the excretion of uric acid.The present study was undertaken to explore the effect and its related mechanisms of soluble uric acid on the urate excretion PDZ domain containing 1(PDZK1)and ATP-binding cassette transporter,subfamily G,member 2(ABCG2)in HT-29 and Caco-2 cell lines.MethodsHT-29 and Caco-2 cell lines were pretreated with or without inhibitors and then stimulated with soluble uric acid.Western blotting and qRT-PCR were used to measure protein and mRNA levels.Subcellular fractionation methods and immunofluorescence were used to quantify the proteins in different subcellular compartments.Flow cytometry experiments examined the function of ABCG2.siRNA transfection was used to assess the interaction between ABCG2 and PDZK1.ResultsSoluble uric acid increased the expression of PDZK1 and ABCG2 in human intestinal cell lines,depending on Toll-like receptor 4/NOD-like receptor superfamily,pyrin domain containing 3(NLRP3)/caspase-1 and phosphatidylinositol-4,5-bisphosphate 3/kinase(PI3K)/protein kinase B(Akt)signaling pathway.The stimulation of soluble uric acid facilitated the translocation of ABCG2 from intracellular compartment to plasma membrane and increased the transport activity.Furthermore,PDZK1 knockdown inhibited the expression and transport activity of ABCG2 regardless of the activation by soluble uric acid.ConclusionThe expression of PDZK1/ABCG2 is mediated by the stimulation of the soluble uric acid in HT-29 and Caco-2 cell lines through the TLR4/NLRP3/caspase-1 and PI3K/Akt signaling pathways.PDZK1 plays a pivotal role in the regulation of ABCG2.