Different dynamics of NLRP3 inflammasome-mediated IL-1β production in GM-CSF– and M-CSF–differentiated human macrophages

Abstract

IL-1b is a "master" cytokine regulating a wide variety of physiologic and immunologic processes. The most frequently studied models for NLRP3 inflammasomemediated IL-1b production are the macrophages; however, depending on their microenvironment, they can develop into functionally different cells. Several protocols have been developed to model the diversity of these cells in vitro. Here, we report for the first time, to our knowledge, a comparative study about the dynamics and molecular mechanisms of NLRP3 inflammasome priming and activation in LPS-stimulated, human, monocytederived GM-or M-macrophages, differentiated in the presence of GM-CSF or M-CSF, respectively. Our results show that IL-1b production by LPS-stimulated M-macrophages is a rapid and short event that requires ATP supplementation and is attenuated, in part, by the presence of IL-10, which reduces Akt signaling. However, IL-1b production by GMmacrophages develops gradually, and these cells produce IL-1b, even in the absence of ATP supplementation, because of the constitutively active caspase-1 enzyme. We show that the membranebound ectonucleotidases have an important regulatory role on the IL-1b secretion in GM-macrophages. Furthermore, we provide evidence that adenosine treatment enhances LPS-primed IL-1b secretion by GM-macrophages, but not by M-macrophages. These results show that, because of the different activation status and expression levels of the NLRP3 inflammasome components, as well as the signaling activity of the pathways, the two subtypes of macrophages respond very differently to the same stimuli. For this reason, the molecular composition of the microenvironment that shapes macrophage development should be considered when research or therapeutic methods are planned to control IL-1b production.

Bisdemethoxycurcumin and Its Cyclized Pyrazole Analogue Differentially Disrupt Lipopolysaccharide Signalling in Human Monocyte-Derived Macrophages

“…Because the functional effects of curcumin and GG6 could not be tested using flow cytometry, we measured IL-1 β release by LPS-stimulated macrophages (see also [ 13 ]). Basal IL-1 β release by CSF-1-differentiated macrophages in the absence of inflammasome activator was barely detectable by ELISA (data not shown), consistent with recent studies [ 34 ]. Stimulation with LPS for 24 h significantly increased the release of IL-1 β into the medium (39.5 ± 14.8 pg/ml, n = 3; Figure 8 ).…”

Lipid and Non-lipid Factors Affecting Macrophage Dysfunction and Inflammation in Atherosclerosis

“…As a master regulator of inflammation, IL-1β bioactivity fundamentally affects atherosclerosis as discussed already. A very recent study has revealed some stark, CSF-dependent differences in how and when IL-1β is produced by human MOs, which have implications for atherosclerosis research in vitro (Budai et al, 2017 ). In it, both GM-CSF and M-CSF-derived MOs release similar amounts of IL-1β, yet the release kinetics are dissimilar.…”

“…In it, both GM-CSF and M-CSF-derived MOs release similar amounts of IL-1β, yet the release kinetics are dissimilar. M-CSF-differentiated MOs stimulated with LPS and either ATP or nigericin release a high concentration of IL-1β after just 2 h, which declines substantially after 6 h, returning to baseline levels after 12 h (Budai et al, 2017 ). By contrast, when GM-CSF was used, IL-1β release was more gradual, peaking between 6 and 24 h yet continuing to remain well above baseline at this latter time point.…”

“…Perhaps most intriguing of all was the observation that only a priming signal, in this case LPS, was required for release in GM-CSF-polarized MOs. The authors demonstrated IL-1β release in the absence of “signal 2,” and constitutive caspase-1 activity in these cells (Budai et al, 2017 ). This phenomenon has previously only been shown in Mos (Netea et al, 2009 ).…”

Újdonságok köszvényben: patogenezis, társbetegségek, diagnosztika és terápia

“…Az így aktivált gyulladásos kaszkád során a DC-k mellett a macrophagok, synovialis fibroblastok, hízósejtek és neutrophil granulocyták is aktiválódnak. A különböző sejtek által termelt gyulladásos mediátorok közül kiemelendők a proinflammatoricus citokinek (például IL1, IL6, tumornekrózisfaktor-α [TNFα]), chemokinek (például IL8), mátrixmetalloproteináz enzimek, prosztaglandinok, leukotriének, reaktívoxigén-gyökök [22]. A leukocyták által termelt citokinek a vascularis endotheliumot is aktiválják.…”