[RummyChick]

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4937355/

Human neutrophil peptides inhibit cleavage of von Willebrand factor by ADAMTS13: a potential link of inflammation to TTP

[RummyChick]

Here, we demonstrate for the first time that HNPs inhibit the proteolytic cleavage of peptidyl VWF73 and multimeric von Willebrand factor (VWF) by ADAMTS13 in a concentration-dependent manner. This inhibitory effect appears to be mediated by tight binding between HNPs and the VWF-A2 domain, which presumably competes for binding of ADAMTS13 to VWF and renders it resistant to proteolysis. Plasma levels of HNPs1-3 or HNP1, HNP2, and HNP3 are all markedly increased in patients with acquired autoimmune TTP who have severe deficiency of plasma ADAMTS13 activity. Together, our findings demonstrate a novel biological function of HNPs1-3, and suggest a potential link between inflammation, neutrophil activation, and microvascular thrombosis in TTP and possibly other inflammation-associated thrombotic disorders.