Potent and Broad but not Unselective Cleavage of Cytokines and Chemokines by Human Neutrophil Elastase and Proteinase 3

Abstract

In two recent studies we have shown that three of the most abundant human hematopoietic serine proteases—mast cell chymase, mast cell tryptase and neutrophil cathepsin G—show a highly selective cleavage of cytokines and chemokines with a strong preference for a few alarmins, including IL-18, TSLP and IL-33. To determine if this is a general pattern for many of the hematopoietic serine proteases we have analyzed the human neutrophil elastase (hNE) and human proteinase 3 (hPR-3) for their cleavage of a panel of 69 different human cytokines and chemokines. Our results showed that these two latter enzymes, in sharp contrast to the two previous, had a very potent and relatively unrestrictive cleavage on this panel of targets. Almost all of these proteins were cleaved and many of them were fully degraded. In light of the proteases abundance and their colocalization, it is likely that together they have a very potent degrading activity on almost any protein in the area of neutrophil activation and granule release, including both foreign bacterial or viral proteins as well as various self-proteins in the area of inflammation/infection. However, a few very interesting exceptions to this pattern were found indicating a high resistance to degradation of some cytokines and chemokines, including TNF-α, IL-5, M-CSF, Rantes, IL-8 and MCP-1. All of these are either important for monocyte-macrophage, neutrophil or eosinophil proliferation, recruitment and activation, suggesting that cytokines/chemokines and proteases may have coevolved to not block the recruitment of monocytes–macrophages, neutrophils and possibly eosinophils during an inflammatory response involving neutrophil activation.

Responses of Mast Cells to Pathogens: Beneficial and Detrimental Roles

“…Many questions are still unanswered regarding the formation of MCETs and its role on MC responses to pathogens; among them, whether MCETs might restrict the inflammatory response by breaking down cytokines and chemokines, as described in NETs (147). In this context, in vitro assays showed that MC tryptase and chymase could cleave a lower number of cytokines and chemokines than neutrophil proteases (148)(149)(150). Interestingly, when combining both MC proteases, three of the most potent Th2 cytokines (thymic stromal lymphopoietin, IL-18 and IL-33) were cleaved (149), indicating that in vivo they might exert a potent negative feedback loop or a regulatory role on anti-parasitic immunity.…”

Staphylococcus aureus Depends on Eap Proteins for Preventing Degradation of Its Phenol-Soluble Modulin Toxins by Neutrophil Serine Proteases

“…On the one hand, the release of NSP inhibitors by S. aureus prevents degradation of PSMs and other virulence factors, which could exacerbate inflammation. On the other hand, inhibition of NSP could prevent NSP-induced endogenous inflammation, since NSP have a broad cleavage profile and also cleave various endogenous molecules, thereby inducing inflammation ( 45 ). Therefore, the release of three NSP inhibitors by S. aureus could be a hint that enhanced survival of S. aureus in contact with neutrophils is also associated with a balanced or even attenuated inflammation.…”

Hindrance of the Proteolytic Activity of Neutrophil-Derived Serine Proteases by Serine Protease Inhibitors as a Management of Cardiovascular Diseases and Chronic Inflammation

“…NSPs regulate inflammatory processes via several means, including proteolytic truncation of chemokines, cytokines, and growth factors to modulate their activity, activation or shedding of cell-surface receptors at the sites of inflammation, and controlling pathways of apoptosis ( Pham, 2008 ; Hahn et al, 2019 ). The recent research findings illustrate that CatG systematically degrades fibroblast growth factor-1 (FGF-1), IL-3, IL-6, IL-7, IL-15, IL-18, IL-31, and IL-33, stem cell factor (SCF), whereas NE and PR3 completely cleave cytokine ciliary neurotrophic factor (CNTF), connective tissue growth factor (CTGF), FGF-1, FGF-9, FGF-19, FMS-like tyrosine kinase 3 ligand (flt3L), granulocyte colony-stimulating factor (G-CSF), insulin-like growth factor-1 (IGF-1), IGF-2, IL-3, IL-7, IL-15, IL-16, IL-17A, IL-31, IL-33, neuregulin-1b, SCF, thymic stromal lymphopoietin (TSLP), but not IL-1-α, IL-5, IL-8, monocyte chemoattractant protein-1 (MCP-1), macrophage colony-stimulating factor (M-CSF), RANTES, TNF-α, which are resistant to proteolysis, proposing that NSPs selectively preserve a specific set of cytokines and chemokines necessary for recruitment of inflammatory cells to the sites of tissue damage or infection ( Fu et al, 2017 ; Fu et al, 2020 ). Furthermore, PR3 can promote apoptosis in aging neutrophils via an activating cleavage of procaspase-3 in the cytosol of neutrophils.…”