Increased histidine decarboxylase expression during in vitro monocyte maturation; a possible role of endogenously synthesised histamine in monocyte/macrophage differentiation.
OBJECTIVE
In this study the expression of histidine decarboxylase (HDC), the pivotal enzyme in histamine formation and the effect of endogenously produced histamine on differentiation antigens was examined during in vitro differentiation of human monocytes.


METHODS
Human elutriated monocytes from healthy volunteers were incubated with macrophage colony stimulating factor (M-CSF) and the expression of HDC was followed at both mRNA and protein levels. To study the possible function of histamine we followed the expression of some cell surface markers (CD14, CD16, CD91, CD49d and CD11c) relevant for phagocytic differentiation upon incubation in the presence of different histamine inhibitors, an HDC inhibitor: S(+)-alpha-fluoromethyl-histidine HCl, (alphaFMH), a compound that disturbs the interaction of histamine with intracellular cyp450 moieties: N,N-diethyl-2-[4-(phenylmethyl) phenoxy]-ethanamine HCI, (DPPE); and H1 and H2 receptor antagonists, Triprolidine and Cimetidine.


RESULTS
During in vitro culture of elutriated human monocytes, in the presence of M-CSF, the gene expression and biosynthesis of HDC was considerably increased. The various antihistamine agents decreased the expression of the cell surface markers examined in this study.


CONCLUSIONS
These data support the elevation of HDC expression during human monocytic differentiation and the possibility that monocyte-derived histamine is partially involved in regulation of M-CSF induced in vitro human monocyte/macrophage phagocytic differentiation.
László
V
V
Institute for Clinical Chemistry and Laboratory Medicine, University of Regensburg, Germany.
Rothe
G
G
Hegyesi
H
H
Szeberényi
J B
JB
Orsó
E
E
Schmitz
G
G
Falus
A
A
D015703:Antigens, CD / Q000096:biosynthesis; D000954:Antigens, Surface / Q000096:biosynthesis; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D005434:Flow Cytometry; D006632:Histamine / Q000502:physiology*; D006640:Histidine Decarboxylase / Q000096:biosynthesis*; D006801:Humans; D039441:Integrin alpha4; D016167:Integrin alphaXbeta2 / Q000096:biosynthesis; D018950:Lipopolysaccharide Receptors / Q000096:biosynthesis; D008264:Macrophages / Q000502:physiology*; D009000:Monocytes / Q000201:enzymology*; D012333:RNA, Messenger / Q000096:biosynthesis; D017452:Receptors, IgG / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction
D015703:Antigens, CD; D000954:Antigens, Surface; D016167:Integrin alphaXbeta2; D018950:Lipopolysaccharide Receptors; D012333:RNA, Messenger; D017452:Receptors, IgG; D039441:Integrin alpha4; D006632:Histamine; D006640:Histidine Decarboxylase