title: Kinetics of manganese transport and gene expressions of manganese transport carriers in Caco-2 cell monolayers.
abstract: Two experiments were conducted to investigate the kinetics of manganese (Mn) transport in Caco-2 cell monolayers and the gene expressions of Mn transport carriers in apical (AP) and basolateral (BL) membranes. In experiment 1, the cells were treated with the medium containing 146 μmol/L of Mn (MnSO4·H2O). Both the uptake and transport of Mn from AP-BL or from BL-AP at different time-points were assessed to determine the optimal time for kinetics of Mn transport. The transport of Mn increased linearly with higher efficiency values in AP-BL than in BL-AP direction, however, the uptake of Mn revealed an asymptotic pattern within 120 min. In experiment 2, the kinetics of Mn transport in AP-BL was determined with media containing Mn concentrations from 0 to 2,500 μmol/L at 40 and 120 min, respectively, and mRNA levels of divalent metal transporter 1 (DMT1) and ferroportin (FPN1) were determined in Caco-2 cells treated with the medium containing 0 or 800 μmol/L of Mn for 120 min. The kinetics of Mn transport showed a carrier-mediated process when Mn concentrations were lower than 1,000 μmol/L and a linear increment when Mn concentrations exceeded 1,000 μmol/L at either 40 or 120 min. Mn treatment decreased (P < 0.01) DMT1 mRNA level and increased (P < 0.01) FPN1 mRNA level. The results from the present study suggested that Mn transport in AP-BL fit both carrier-mediated saturable and non-saturable diffusion processes, and Mn transport carriers DMT1 and FPN1 mediate the apical uptake and basolateral exit of Mn in Caco-2 cells.
authors.affiliation: Mineral Nutrition Research Division, Institute of Animal Science, Chinese Academy of Agricultural Sciences (CAAS), No. 2 Yuanmingyuan West Road, Haidian District, Beijing, 100193, People's Republic of China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Li
authors.forename: Jingjing
authors.initials: J
authors.lastname: Xie
authors.forename: Lin
authors.initials: L
authors.lastname: Lu
authors.forename: Liyang
authors.initials: L
authors.lastname: Zhang
authors.forename: Lingyan
authors.initials: L
authors.lastname: Zhang
authors.forename: Yaxue
authors.initials: Y
authors.lastname: Zou
authors.forename: Qiuyue
authors.initials: Q
authors.lastname: Wang
authors.forename: Xugang
authors.initials: X
authors.lastname: Luo
authors.forename: Sufen
authors.initials: S
authors.lastname: Li
mesh_terms: D018938:Caco-2 Cells; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D016764:Cell Polarity; D015870:Gene Expression; D006801:Humans; D017136:Ion Transport; D007700:Kinetics; D008345:Manganese / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D000098742:Ferroportin
chemical_list: D027682:Cation Transport Proteins; C110547:DMRT1 protein; D012333:RNA, Messenger; D014157:Transcription Factors; D000098742:Ferroportin; D008345:Manganese