Human neutrophils uniquely release TIMP-free MMP-9 to provide a potent catalytic stimulator of angiogenesis

Abstract

Several lines of evidence have implicated matrix metalloproteinase 9 (MMP-9) as a protease inducing an angiogenic switch critical for tumor progression. Among MMP-9-expressing cell types, including cancer cells and tumor-associated leukocytes, inflammatory neutrophils appear to provide an important source of MMP-9 for tumor angiogenesis. However, delivery of MMP-9 by neutrophils has not been mechanistically linked to its catalytic activity at the angiogenic site. By using a modified angiogenic model, allowing for a direct analysis of exogenously added cells and their products in collagen onplants grafted on the chorioallantoic membrane of the chicken embryo, we demonstrate that intact human neutrophils and their granule contents are highly angiogenic. Furthermore, purified neutrophil MMP-9, isolated from the released granules as a zymogen (proMMP-9), constitutes a distinctly potent proangiogenic moiety inducing angiogenesis at subnanogram levels. The angiogenic response induced by neutrophil proMMP-9 required activation of the tissue inhibitor of metalloproteinases (TIMP)-free zymogen and the catalytic activity of the activated enzyme. That the high angiogenic potency of neutrophil proMMP-9 is associated with its unique TIMPfree status was confirmed when a generated and purified stoichiometric complex of neutrophil proMMP-9 with TIMP-1 failed to induce angiogenesis. Recombinant human proMMP-9, operationally free of TIMP-1, also induced angiogenesis at subnanomolar levels, but lost its proangiogenic potential when stoichiometrically complexed with TIMP-1. Similar proMMP-9/TIMP-1 complexes, but naturally produced by human monocytic U937 cells and HT-1080 fibrosarcoma cells, did not stimulate angiogenesis. These findings provide biochemical evidence that infiltrating neutrophils, in contrast to other cell types, deliver a potent proangiogenic moiety, i.e., the unencumbered TIMPfree MMP-9.inflammation ͉ chick embryo model

Coordinate activation of inflammatory gene networks, alveolar destruction and neonatal death in AKNA deficient mice

“…These data additionally emphasize the relevance of mechanisms that may be involved in the initiation and progression of complex pathologies such as anaphylaxis and tumorigenesis [23,56,57,59]. Although our studies are by no means exhaustive, the combined data from AKNA KO and KO2 mice concur with our hypothesis that AKNA has a regulatory function on gene transcription networks, which we suggest is linked to the mechanisms that control the degree of neutrophil responses to pathogen invasion ( Figure 8D).…”

“…For instance, human and mouse AKNA genes are respectively located within fragile chromosome 9 FRA9E and 4 FRA4C2 regions, and these loci are known to be frequently altered in inflammatory diseases and cancer [24,58]. This suggests that, in humans, AKNA gene lesions could be a determining risk factor for how neutrophilmediated inflammatory reactions resolve into acute syndromes and/or neoplastic disorders [59]. Although we make no parallel between AKNA and HMG proteins, we speculate that given the evidence of HMGA1 direct contribution to neoplastic transformation [60][61][62], the shared involvement in inflammation [54], and the linkage of SNP at human AKNA AT-hook domain with higher risk for cervical cancer [23], physiopathological cooperation is at least plausible.…”

Evaluation of the prognostic value of systemic inflammation and socioeconomic deprivation in patients with resectable colorectal liver metastases

“…43 Furthermore, granulocytes, particularly neutrophils, contain over two-thirds of circulating vascular endothelial growth factor, liberation of which may promote tumour vascularisation. 44 Neutrophils may further promote invasion and metastasis through the production and release of matrix metalloproteinases 45 and the promotion of cancer cell intra-and extravasation. 46,47 Though subordinate to neutrophil count in multivariable analyses, an association between monocyte count and adverse outcome was also demonstrated in this study.…”

The Collagen Binding Domain of Gelatinase A Modulates Degradation of Collagen IV by Gelatinase B

“…MMP9 is an MMP expressed and released by neutrophils 41 and is involved in the "angiogenesis switch," 42,43 in cancer progression, 44,45 in vascular invasion 46 and in chronic inflammatory processes, including the autoimmune diseases multiple sclerosis and rheumatoid arthritis. [47][48][49] Therefore, functional modulation of MMP9 enzymatic activity is of crucial importance for better comprehension of several pathological events.…”