Preliminary evaluation of a murine model to determine the impact of neutrophil IL-1β in Hemolytic Uremic Syndrome development.

DOUGLAS VERA AGUILAR; IRENE A. KEITELMAN; FLORENCIA SABBIONE; CAROLINA M. SHIROMIZU; ALEXIA VEREERTBRUGGHEN; MÓNICA VERMEULEN; MANUELA PIZZANO; ALAN BERNAL; ROMINA FERNÁNDEZ BRANDO; AGOSTINA CERNUTTO; JEREMÍAS GALLETTI; MARINA PALERMO; ANALÍA S. TREVANI

San Luis

Congreso; LXXI Reunión Anual de la Sociedad Argentina de Inmunología; 2023

Neutrophils are recruited to the gut upon infection with the enteric pathogen Shiga toxin-producing Escherichia coli (STEC). There, they can deploy their microbicidal battery to fight against the pathogen. However, they can be also responsible for the extensive tissue damage that accompanies these infections and that impacts the development of a systemic disease known as Hemolytic Uremic Syndrome (HUS). In Argentina, HUS is endemic showing high incidence in children under five years. There is still no treatment to prevent the progression of the disease or an effective vaccine. We previously found that human neutrophils secrete IL-1β upon challenge with STEC (O157:H7) by a pathway that involves neutrophil serine proteases (NSP) and caspase-1 activity. We here conducted preliminary studies to determine if a murine model would be appropriate to investigate both the role of neutrophil IL-1β in HUS development and the capacity of inhibitors of this secretion to halt the progression to this syndrome. With this aim, we isolated peritoneal cells from either Balb/c or C57BL6 mice after 6-h intraperitoneal injection of Thioglycolate 6% and determined the percentage of granulocytes in these samples. Then, we challenged ex vivo those cell samples containing ~58%-73% of granulocytes with STEC (O157:H7) at a multiplicity of infection (MOI) of 0.5, either in the presence or absence of a PAN-serine protease inhibitor (AEBSF 0.1M) or a caspase-1/4 inhibitor (VX-756 50 µM). After 3 h, we evaluated IL-1β concentrations in culture supernatants. Our results indicated that AEBSF and VX-765 significantly inhibited IL-1β secretion induced by STEC (Balb/c AEBSF n=5; p