title: Impairment of the Cellular Distribution and Stability of the Erythropoietin Receptor Through the Direct Targeting of Aristolochic Acid.
abstract: Aristolochic acid (AA) nephropathy is complicated with early onset and severe anemia. The molecular pathological mechanism of AA-induced anemia remains unclear. The aim of this study was to evaluate the putative pathological roles of the erythropoietin receptor (EPOR) in AA-induced anemia in both AA nephropathy zebrafish and cultured human renal tubular cells (HK2). Immunofluorescence staining experiments revealed that AA colocalizes with the EPOR in zebrafish embryos as well as in the cytoplasm of HK2 cells. After exogenous EPO stimulation, the EPOR was detected in the plasma membrane of HK cells. However, cotreatment with AA and EPO inhibited EPOR signaling and its membrane localization upon EPO stimulation. The results of studies with a protein synthesis inhibitor and a lysosome inhibitor revealed that AA accelerates the lysosomal degradation of EPOR. The molecular docking results suggest that AA may interact with the N-terminus of EPOR. Together with the results of light absorption and in vitro competition assays, we concluded that AA treatment impairs EPOR membrane localization, accelerates its lysosomal degradation, and consequently downregulates EPOR signaling by direct targeting. The results of this study may further detail the pathological mechanism of severe anemia complicated with AA nephropathy.
authors.affiliation: *Department of Chemistry, Tamkang University, Tamsui, New Taipei City 251, Taiwan; fish3970@gmail.com.
authors.forename: Yau-Hung
authors.initials: YH
authors.lastname: Chen
authors.affiliation: Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan;
authors.forename: Chi-Yuan
authors.initials: CY
authors.lastname: Chou
authors.affiliation: Department of Nephrology, Chang Gung Memorial Hospital, Keelung, Taiwan; and Kidney Research Center, Chang Gung Memorial Hospital, Chang Gung University, School of Medicine, Taoyuan, Taiwan fish3970@gmail.com.
authors.forename: Chiao-Yin
authors.initials: CY
authors.lastname: Sun
mesh_terms: D000740:Anemia / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology; D000818:Animals; D034341:Aristolochic Acids / Q000633:toxicity*; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007674:Kidney Diseases / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology; D008247:Lysosomes / Q000187:drug effects; D062105:Molecular Docking Simulation; D017467:Receptors, Erythropoietin / Q000187:drug effects*; D015398:Signal Transduction / Q000187:drug effects; D015027:Zebrafish
chemical_list: D034341:Aristolochic Acids; D017467:Receptors, Erythropoietin; C000228:aristolochic acid I
keywords: anemia; aristolochic acid; erythropoietin receptor; lysosome; molecular docking