The priming action of tumour necrosis factor-alpha (TNF-α) and granulocyte-macrophage colony-stimulating factor (GM-CSF) on neutrophils activated by inflammatory microcrystals

Abstract

SUMMARYWe studied the effects of TNF-a or GM-CSF on the production of reactive oxygen species (as measured by chemiluminescence) and degranulation responses of neutrophils to opsonized inflammatory microcrystals. TNF-a in the 10-2000 pM or GM-CSF in the 2-200 pM concentration range caused the concentration-dependent amplification of neutrophil chemiluminescence responses to both calcium pyrophosphate dihydrate (CPPD) and monosodium urate monohydrate (MSUM) crystals. Degranulation responses, as measured by the extracellular release of the granule enzymes myeloperoxidase or lysozyme, were amplified by Ϸ 50-100% for both MSUM or CPPD crystal-induced neutrophil activation when cells were pretreated with TNF-a at 2000 pM or GM-CSF at 75 pM.

Pseudogout-Associated Inflammatory Calcium Pyrophosphate Dihydrate Microcrystals Induce Formation of Neutrophil Extracellular Traps

“…Previous reports have already indicated and we confirmed that CPPD crystals stimulate a robust respiratory burst in human neutrophils (Fig. 4A-C) (24,49). To our surprise, we found that DPI had no significant effect on CPPD crystal-triggered extracellular DNA release in our hands (Fig.…”

“…This response is quick, faster than that observed with the maximal NET inducer, protein kinase C activator PMA (increase in PMA-stimulated extracellular DNA levels appears 60-90 min after stimulation) (35). The CPPD crystal dose range (0-250 mg/ml) used in our work is lower than the ones used in previous CPPD-neutrophil studies (10,24,25,49). MSU crystals were shown to induce NETs in this exact same range (26,27).…”

“…Little is known, however, about the interactions of MSU or CPPD crystals with neutrophils, the major cell type present in synovial fluid of gout and pseudogout patients (12). Neutrophils interact with MSU and CPPD crystals, and respond with respiratory burst and cytokine release (10,49). However, the fate of neutrophils after crystal exposure is unknown.…”

“…CPPD crystals activate the NLRP3 inflammasome in macrophages, causing release of proinflammatory IL1b (15). TNF-a and GM-CSF are known priming agents of neutrophil effector functions, and they have been shown to increase ROS production and degranulation of neutrophils exposed to CPPD crystals (49,50). We asked, therefore, whether proinflammatory cytokine priming of neutrophils by TNF-a, IL-1b, or GM-CSF would affect CPPD-induced NET formation.…”

The effect of inhibiting topoisomerase I and II on the antiapoptotic response associated with pro-inflammatory crystals of calcium pyrophosphate dihydrate in human neutrophils

“…The incidence of CPPD deposition in joints is estimated to be 3.6 % of the population [1]. Crystals deposited in the synovium become opsonized with proteins from the synovial fluid, and interact with various synovial cells leading to the release of chemotactic factors [2].…”