Activation of Toll Like Receptors 7 and 8 on CD34+ cells by Coxsackievirus B3 impairs megakaryocyte and platelet production

RODRIGUEZ, C; CHARÓ, NL; ONETO, P; GÓMEZ, R; DATRI, P; SCHATTNER, M

Congreso; LXVI REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INVESTIGACIÓN CLÍNICA (SAIC); 2021

Background: Increasing evidence indicates that hematopoietic progenitor cells (CD34+ cells), megakaryocytes (MKs), and platelets (PLT) express toll-like receptors (TLR) allowing the contribution of these cells to the immune response and inflammation. However,whether TLRs’ activation on CD34+ modulates megakaryo/thrombopoiesis during viral infections is still unclear.Objectives: We evaluated whether the single-strand RNA Coxsackievirus B3 (CVB3) infection modulates human MK development and PLT production through TLR7/8 activation.Methods: CD34+ cells from the human umbilical cord were exposed to CVB3 or UV-irradiated CVB3 virus (mock) and then stimulated with thrombopoietin (TPO) in the presence or absence of TLR7/8 antagonists. The total number of cells (counting in a Neubauer chamber), CD34+ differentiation, maturation of MKs, PLT biogenesis (flow cytometry), and expression of Fli-1, RUNX-1, and NF-E2 (qPCR) were determined after 12-17 days post-infection (dpi).Results: Exposure of CD34+ cells to CVB3 resulted in productive infection as determined by the presence of viral infectious particles in culture supernatants 1 to 11 dpi. Interestingly, CD34+ differentiation towards MKs (CD41+ cells) as well as MK maturation (CD42b+ cells), were markedly impaired (n=6, p