Histidine-rich glycoprotein (
HRG) treatment ameliorated the survival rate of septic mice by suppressing excess immunothrombus formation. Although such findings suggested that
HRG may be one of the most useful drugs for
sepsis, obtaining a stable experimental system to standardize the
HRG drug product is difficult to achieve using neutrophils isolated from volunteers. This is due to the short survival time and individual differences of human neutrophils. In the present study, we determined whether the differentiated neutrophil-like cell lines exhibited similar responses to
HRG compared with human purified neutrophils.
All-trans retinoic acid (ATRA) was employed to induce the differentiation of the human
myeloid leukemia cell lines HL-60 and NB-4. Thereafter, the cells were treated with Hank's balanced
salt solution,
human serum albumin, or
HRG. The effects of
HRG on these cells were evaluated according to cell shape, microcapillary passage,
reactive oxygen species (ROS) production, neutrophil extracellular traps (NETs) formation, the expression of activated CD11b, and cell viability.
HRG maintained the round shape of differentiated neutrophil-like cells, decreased the time required by cells to pass through the microcapillaries, and inhibited ROS production, NETs formation, and the expression of activated CD11b on the cell surface. Moreover, the cells could survive longer in the presence of
HRG than the control. The ATRA-induced differentiated cell lines could be used as alternatives to neutrophils to investigate the effects of
HRG on neutrophils. This method can thus be used as an essential standardization test in
pharmaceutical development. SIGNIFICANCE STATEMENT: Human neutrophils exhibit varying responses to
histidine-rich glycoprotein (
HRG); however,
all-trans retinoic acid-induced differentiated neutrophil-like cell lines can be used as reliably proxies to investigate the effects of
HRG on neutrophils. Additionally, these cell lines can be employed in the development of
therapies for the treatment of
sepsis.