title: HMGB1 release by human liver L02 and HepG2 cells induced by lipopolysaccharide.
abstract: Liver cells release the high mobility group box-1 (HMGB1) protein when exposed to lipopolysaccharides (LPSs). However, the timing and levels of protein released remain unclear. The present study aimed to characterize the secretion of the late pro-inflammatory cytokine HMGB1 by liver L02 and HepG2 cells. The human mononuclear macrophage cell line U937 was used as a control. Various concentrations of LPS were added to human U937, L02 and HepG2 cells for different durations, and the cells were analyzed at different time-points following this addition. Reverse transcription polymerase chain reaction (RT-PCR) was used to measure cellular HMGB1 mRNA levels, western blotting was performed to detect HMGB1 in cellular supernatants and the translocation of HMGB1 from the nucleus to the cytosol was examined using immunofluorescence staining. L02 and HepG2 cells exhibited higher HMGB1 mRNA levels compared with the control U937 cells 20 and 24 h following continuous exposure to LPS. U937 cells exhibited higher HMGB1 mRNA levels compared with the corresponding L02 and HepG2 cells 16 h following LPS exposure. The phase of HMGB1 protein detected in the cellular supernatants of L02 and HepG2 cells (16 h) was later than that of U937 cells (8 h). For the three cell lines, HMGB1 levels demonstrated a time dependency; however, the protein level was the highest in U937 cells. In the three cell lines, translocation of HMGB1 from the nucleus to the cytosol occurred; however, the phases of HMGB1 translocation in L02 and HepG2 cells occurred later than in U937 cells. LPS-induced secretion of the late pro‑inflammatory cytokine HMGB1 by liver cells is characterized by a late phase of release and smaller quantity, and the process of HMGB1 secretion appears to be associated with HMGB1 translocation.
authors.affiliation: Department of Infectious Diseases, Xiangya Hospital, Central South University, Hunan, PR China.
authors.forename: Ze-Bing
authors.initials: ZB
authors.lastname: Huang
authors.forename: Xia-Hong
authors.initials: XH
authors.lastname: Dai
authors.forename: Mei-Fang
authors.initials: MF
authors.lastname: Xiao
authors.forename: Rong-Rong
authors.initials: RR
authors.lastname: Zhou
authors.forename: Shu-Shan
authors.initials: SS
authors.lastname: Zhao
authors.forename: Bao-Xin
authors.initials: BX
authors.lastname: Zhang
authors.forename: Pan-Pan
authors.initials: PP
authors.lastname: Yi
authors.forename: Ruo-Chan
authors.initials: RC
authors.lastname: Chen
authors.forename: Wen-Ting
authors.initials: WT
authors.lastname: Li
authors.forename: Ai-Madhagi
authors.initials: AM
authors.lastname: Yaser
authors.forename: Yan
authors.initials: Y
authors.lastname: Huang
authors.forename: Xue-Gong
authors.initials: XG
authors.lastname: Fan
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D024243:HMGB1 Protein / Q000096:biosynthesis* / Q000235:genetics; D056945:Hep G2 Cells; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D014176:Protein Biosynthesis / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020298:U937 Cells
chemical_list: D024243:HMGB1 Protein; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D007770:L-Lactate Dehydrogenase