TABLE 2

Synopsis of the stimulatory effects of HA on [Ca2+]i in various human myeloid cell types and the HxR subtypes and G proteins involved

Summary of the stimulatory effects of HA on [Ca2+]i in human myeloid cells. For some cell types, such as dimethylsulfoxide-differentiated HL-60 cells and U937 promonocytes, stimulatory effects of HA were not observed in all studies (indicated by yes/no). Subtle cell strain differences or differences in cell culture conditions may account for these discrepancies. Most studies on cells other than eosinophils focused on H1R and H2R antagonists because these antagonists were fully sufficient to explain the observed effects of HA. In parentheses, the differentiation-inducing compound is given. In all cell types studied, appropriate control ligands, such as ATP, fMLP, or platelet-activating factor, were used to demonstrate functionality of cells. Information about the G proteins involved in signaling is provided as far as possible. Partially PTX-insensitive effects are always difficult to interpret because complete ADP-ribosylation of Gi proteins must be checked (Cowen et al., 1990; Wenzel-Seifert and Seifert, 1990).

Cell TypeStimulatory Effect of HAHxR InvolvedG Proteins InvolvedReferences
NeutrophilsNoNANASeifert et al., 1992c
EosinophilsYesH4R, H1R excludedGi, no evidence for GqRaible et al., 1994;
Buckland et al., 2003;
Reher et al., 2012
MonocytesNoNANATriggiani et al., 2007;
This study
HL-60 promyelocytesYesH1R/H2RGqSeifert et al., 1992a
HL-60 neutrophils (DMSO)Yes/NoH2RGqMitsuhashi et al., 1989
HL-60 neutrophils (retinoic acid)YesH1R/H2RGqBurde and Seifert, 1996
HL60 neutrophils (dibutyryl-cAMP)YesH1RGi and GqSeifert et al., 1992c
HL-60 monocytes (vitamin D3)YesH1R, H4R excludedGi and GqSeifert et al., 1994
U937 promonocytesYes/NoH1R, H4R excludedGq?Seifert et al., 1992a;
This study
U937 monocytes (vitamin D3)YesH1RGq?This study
U937 monocytes (interferon-γ)YesH1RGq?This study
U937 monocytes (dibutyryl-cAMPYesH1RGq?This study
HELNoNANASeifert et al., 1992a
K562NoNANASeifert et al., 1992a
  • DMSO, dimethylsulfoxide; NA, not applicable.