Antimicrobial activity of HL-60 cells compared to primary blood-derived neutrophils against Staphylococcus aureus

Abstract

BackgroundThe human leukemia cell line HL-60 is considered an alternative cell culture model to study neutrophil differentiation and migration. The aim of this study was to characterize the suitability of HL-60 cells differentiated to neutrophil-like cells (nHL-60) as substitute for blood-derived human neutrophils to investigate the interaction of neutrophils with Staphylococcus aureus.MethodsFor this purpose, antimicrobial activity, bacterial uptake, production of reactive oxygen species and the release of neutrophil extracellular traps (NETs) by nHL-60 cells were analyzed and compared to primary blood-derived neutrophils using Staphylococcus aureus as important human and animal pathogen.ResultsOverall, the antimicrobial activities of nHL-60 cells were distinctly lower compared to blood-derived neutrophils. Furthermore, production of reactive oxygen species as well as NET formation was clearly impaired in nHL-60 cells.ConclusionThis study indicates that HL-60 cells are of limited usage as an alternative model to study antimicrobial functions of neutrophils against Staphylococcus aureus.Electronic supplementary materialThe online version of this article (doi:10.1186/s12952-017-0067-2) contains supplementary material, which is available to authorized users.

The influence of agents differentiating HL‐60 cells toward granulocyte‐like cells on their ability to release neutrophil extracellular traps

“…It has been underlined that the extensive heterogeneity among HL‐60 cells of different sublines and from various sources is consequently responsible for the variable properties of these cells differentiated with DMF or ATRA . Interestingly, Yaseen et al., when comparing the antimicrobial activity of DMSO‐ and ATRA‐dHL‐60 cells, found lower NETs release by ATRA‐dHL‐60 cells than by DMSO‐dHL‐60 cells upon stimulation with PMA and S. aureus or PMA alone, which is contrary to our reports . It cannot be excluded that these discrepancies result from the use of different sources of HL‐60 cells.…”

“…What is more, even though we observed increased ROS formation upon PMA or CI treatment both in DMF‐dHL‐60 cells and PBN, the kinetics and the amount of released ROS differed. Our observations are in accordance with previously published data that only up to 10% of differentiated HL‐60 cells release NETs and that dHL‐60 cells do not release ROS as vigorously as PBN . Intriguingly, we could only detect oxidative burst post stimulation with CI using DHR oxidation assay, but not NBT reduction test.…”

“…Our observations are in accordance with previously published data that only up to 10% of differentiated HL-60 cells release NETs and that dHL-60 cells do not release ROS as vigorously as PBN. 27,30,38 Intriguingly, we could only detect oxidative burst post stimulation with CI using DHR oxidation assay, but not NBT reduction test. It is conceivable that these two assays have different sensitivities toward free radicals.…”

“…HL‐60 cell line, human promyelocytic leukemia cells, can be differentiated into granulocyte‐like cells using a wide variety of agents, such as all‐trans retinoic acid (ATRA), butyrate, hypoxanthine, dimethyl sulfoxide (DMSO) or dimethylformamide (DMF) . Differentiated HL‐60 cells (dHL‐60) have already been applied in studies deciphering mechanisms of NETs formation . It was reported that dHL‐60 cells were able to release NETs in response to a variety of stimuli, including both synthetic (ROS‐dependent phorbol 12‐myristate 13‐acetate (PMA) and ROS‐independent calcium ionophore (CI)) and physiological NETosis inducers ( C. albicans, S. flexneri, S. aureus and interleukin‐8).…”

“…25,26 Differentiated HL-60 cells (dHL-60) have already been applied in studies deciphering mechanisms of NETs formation. [27][28][29][30][31] It was reported that dHL-60 cells were able to release NETs in response to a variety of stimuli, including both synthetic (ROS-dependent phorbol 12myristate 13-acetate (PMA) and ROS-independent calcium ionophore (CI)) and physiological NETosis inducers (C. albicans, S. flexneri, S. aureus and interleukin-8). Importantly, for particular studies distinct differentiating agents were used (ATRA, DMSO, ATRA + DMSO, DMF), even though it has been reported that granulocyte-like cells acquire variable functional characteristics depending on the compound used.…”