title: Dendritic cell depletion in burn patients is regulated by MafB expression.
abstract: Studies have shown that monocytes are hyporesponsive and that dendritic cells (DCs) are depleted in burn patients. We have recently shown in a mouse model that burn injury alters the transcriptional regulation in bone marrow progenitors and inhibits myeloid-derived DC (mDC) production. In the present study, using human burn patient peripheral blood mononuclear cells, we have shown an overexpression of MafB with a corresponding reduction in peripheral blood mononuclear cell-derived mDCs. We isolated mononuclear cells from burn patient (23–68% TBSA) and control volunteer peripheral blood samples by Ficoll gradient centrifugation and cultured mDCs by using a standard ex vivo culture system. Fluorescence-activated cell sorter analysis was used to select myeloid cells based on the cell surface expression of CD45+. The mDC fraction was identified by the expression of human leukocyte antigen (HLA)-DR+CD11c+, and we found a significant reduction in HLA-DR+ leukocytes for up to 4 weeks postburn. MafB expression was then examined in HLA-DR+CD14+ monocytes. Burn injury alters the phenotype of CD14+ monocytes augmenting MafB expression and reducing their differentiation into mDCs. MafB was then silenced in ex vivo culture prior to DC differentiation by using small interfering RNA technique. MafB gene silencing improved the differentiation potential of CD14+ cells into mDCs, increasing the percentage of mDCs by >75%. Furthermore, GATA-1+ and HLA-DR+ mDCs were increased following MafB silencing. Although burn injury augments the number of peripheral blood monocytes, the frequency of mDC is reduced. This impairment is likely secondary to the down-regulation of mDC differentiation by high MafB-expressing monocytes following burn injury.
authors.affiliation: Department of Surgery, Loyola University Medical Center, Maywood, Illinois, USA.
authors.forename: Keneeshia N
authors.initials: KN
authors.lastname: Williams
authors.forename: Andrea
authors.initials: A
authors.lastname: Szilagyi
authors.forename: Li-Ke
authors.initials: LK
authors.lastname: He
authors.forename: Peggie
authors.initials: P
authors.lastname: Conrad
authors.forename: Marcia
authors.initials: M
authors.lastname: Halerz
authors.forename: Richard L
authors.initials: RL
authors.lastname: Gamelli
authors.forename: Ravi
authors.initials: R
authors.lastname: Shankar
authors.forename: Kuzhali
authors.initials: K
authors.lastname: Muthumalaiappan
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D002056:Burns / Q000276:immunology* / Q000378:metabolism; D039521:CD11c Antigen / Q000378:metabolism; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D050982:GATA1 Transcription Factor / Q000378:metabolism; D006684:HLA-DR Antigens / Q000378:metabolism; D006801:Humans; D017493:Leukocyte Common Antigens / Q000378:metabolism; D018950:Lipopolysaccharide Receptors / Q000378:metabolism; D051258:MafB Transcription Factor / Q000096:biosynthesis*; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology* / Q000378:metabolism; D010641:Phenotype; D034741:RNA, Small Interfering
chemical_list: D039521:CD11c Antigen; D050982:GATA1 Transcription Factor; C494688:GATA1 protein, human; D006684:HLA-DR Antigens; D018950:Lipopolysaccharide Receptors; D051258:MafB Transcription Factor; D034741:RNA, Small Interfering; D017493:Leukocyte Common Antigens; C516769:PTPRC protein, human