PROKARIOTIC RNA EFFECTS ON PULMONARY EPITHELIAL AND ENDOTHELIAL CELLS MODULATE THE INMUNE RESPONSE

PITTALUGA JR; CASTILLO LA; BIRNBERG WEISS F; FERNANDEZ, GC.; LANDONI VI

Congreso; LXVIII Reunión Anual de la Sociedad Argentina de Inmunología 2019; 2020

Escherichia coli (ECO), Klebsiella pneumoniae (KPN) and Pseudomonas aeruginosa (PAE) can cause severe pneumonia. Lung epithelial (EpCs) and endothelial cells (ECs) modulate local immuneresponses. In fact, the reciprocal relation between EpCs and ECsas well as their influence on cells from the innate immunity is determinant in the course of infection.At the site of infection, cells are exposed to prokaryotic RNA (pRNA).pRNA’s immunomodulatory role is relevant, but its effect on lung immune response has not been determined. The aim of this work wasto determine the effect of pRNA on EpCs and ECs, and the influenceof their response on neutrophil (PMN). For this, human pulmonaryepithelial (Calu-6), and microvascular endothelial cell line (HMEC-1)were treated with pRNAs from ECO, KPN and PAE, and the result ofthis stimulation was evaluated on PMN response.Activation of Calu-6 and HMEC-1 was induced by ECO and KPNRNA but not by PAE-RNA, as determined by the increased ICAM-1expression by flow cytometry (FACS) (p≤0.01). Also, CALU-6 andHMEC-1 released IL-8 after stimulation with ECO and KPN-RNA (p≤0.001). Consistently, conditioned medium (CM) from both celllines showed chemoattractant activity for PMN after stimulation withECO and KPN-RNA (p≤0.001). Finally, CM from cells treated withECO and KPN-RNA induced PMN activation as determined by theincrement in CD11b expression by FACS (p≤0.01).Moreover, when PMN were treated directly with pRNA, CD11b upregulation was induced only by ECO and KPN-RNA (p≤0.05). Also,all pRNA were able to induce ROS generation (p≤ 0.05). Finally,PMN migration assay revealed that ECO and KPN-RNA resultedchemoattractant (p≤0.01).In conclusion, ECO and KPN-RNA are capable of activating EpCs,ECs and PMN. Also, they induce a response on EpCs and ECs capable of activating and attracting PMN to the site of infection. Inaddition, this study reveals that PAE-RNA constitute a poor stimulusin the context of a pulmonary immune response.