Human neutrophil elastase proteolytic activity in Ulcerative colitis favors the loss of function of therapeutic monoclonal antibodies

RENATA CURCIARELLO; TONI SOBANDE; SAMANTHA JONES; PAOLO GIUFFRIDA; ANTONIO DI SABATINO; GUILLERMO HORACIO DOCENA; THOMAS T. MACDONALD; KLAARTJE KOK

Journal of Inflammation Research

Dove Medical Press

Lugar: Aukland; Año: 2020 vol. 13 p. 233 - 243

1178-7031

Purpose: Proteases play an essential role in the pathophysiology of inflammatorybowel disease (IBD), contributing to the intestinal mucosal lesions through thedegradation of the extracellular matrix and alteration of the barrier function.Ulcerative colitis (UC) is characterized by an extensive infiltrate ofneutrophils into the mucosa and hence, increased proteolytic activity. Humanneutrophil elastase (HNE) is a serine protease that has been reported to beincreased in UC patients´ intestinal mucosa. Based on our previous studies, wehypothesized that HNE might induce proteolytic degradation and loss of functionof therapeutic monoclonal antibodies in IBD patients.Patients and methods: Elastase expression andelastinolytic activity were determined in mucosal explants from ulcerativecolitis patients (n=6) and cultured exvivo in the presence or absence of recombinant elafin. Enzymatic digestionsof therapeutic monoclonal antibodies were performed using recombinant HNE and elafin.The integrity of the therapeutic antibodies was evaluated by immunoblotting andprotein G binding assay, whereas their TNF-neutralizing activity was assessedwith a reporter cell-line.Results: We found that HNE and its elastinolytic activity were increased in the gutmucosa of UC patients. We also demonstrated that HNE cleaved biological drugs,impairing the TNF-α neutralizing capacity of anti-TNF monoclonal antibodies. Thisproteolytic degradation was inhibited by the addition of the specificinhibitor, elafin.Conclusion: Our results suggest that the highlevel of proteolytic degradation by mucosal neutrophil elastase, along with apotential imbalance with elafin, contributes to the loss of function ofbiologic agents, which are currently used in patients with IBD. These findingsmight explain the non-responsiveness of UC patients to therapeutic monoclonalantibodies and suggest the potential beneficial concomitant use of elafin in thistreatment.