Neutrophil Extracellular Traps Generation Relates with Early Stage and Vascular Complications in Systemic Sclerosis.

Systemic sclerosis (SSc) is a systemic disease characterized by a great clinical and immunological heterogeneity whose pathophysiology is still being unraveled. Recently, innate immunity has been proposed to participate to the pathogenesis of SSc. In this study, we investigated the release of neutrophil extracellular traps (NETs) according to patient phenotype. Polymorphonuclear neutrophils (PMN) from 34 SSc patients and 26 healthy controls were stimulated by serum from SSc or healthy subject. NETs were visualized using epifluorescence microscope after DNA, myeloperoxidase, and Histone H3 tagging. Area of NETs were quantified using an original macro running in ImageJ® software. PMN from SSc patients were significantly more prone to releasing NETs than control PMN after autologous stimulation. PMN from patients with severe vascular complications (pulmonary arterial hypertension, digital ulcers) produced more NETs than PMN from other SSc patients and their aberrant NET production appeared to be sustained over time. In patients with pulmonary interstitial disease or extensive cutaneous fibrosis, NET production was high at an early stage of the disease before progressively decreasing. Both serum factors and PMN activation status were involved in the enhanced production of NETs in SSc. Consequently, neutrophils and especially NETosis represent new physiopathological and therapeutic fields in SSc.

Elastin fragments induce IL-1beta upregulation via NF-kappaB pathway in melanoma cells.

In a previous work, we reported the influence of elastin fragments (EFs) on matrix metalloproteinases-2 and -14 expression and activation in melanoma cells in vitro. We hypothesized that EFs might also modulate expression of other mediators involved during melanoma progression. Therefore we investigated the contribution of EFs on IL-1beta expression, a cytokine playing a key role in melanoma cells activation. Our results evidenced that high tumorigenic melanoma cells (M3Da cells) treated with EFs led to IL-1beta mRNA and protein upregulation. The effects of EFs on M3Da cells were found to be mediated by receptor (spliced galactosidase) occupancy, as being suppressed by lactose and reproduced by cell stimulation with the VGVAPG peptide. Binding of EFs to their receptor induced a rapid activation of extracellular signal-regulated kinase 1/2; and p38 mitogen-activated protein kinase pathways. However, these pathways were not associated with IL-1beta mRNA upregulation by EFs. Concomitantly, we demonstrated that EFs stimulation induced NF-kappaB nuclear translocation and DNA binding on IL-1beta promoter region whereas inhibition of NF-kappaB with the specific chemical inhibitor SN-50 or by overexpression of IkappaB, the endogenous inhibitor of NF-kappaB pathway, totally abolished EFs-mediated IL-1beta mRNA overexpression. These results demonstrate that EFs induce NF-kappaB activation, leading to IL-1beta upregulation in invasive melanoma cells.