MODULATION OF MEGAKARYO/THROMBOPOIESIS BY THE VITA-PAMP BRUCELLA ABORTUS RNA

BUENO, JORGELINA; BERTINAT, YASMÍN; SERAFINO, AGUSTINA; MILILLO, M AYELÉN; D'ATRI, L PAOLA; BARRIONUEVO, PAULA

San Luis

Congreso; Reunión Anual de la Sociedad Argentina de Inmunología (SAI) 2023; 2023

SAI

Thrombocytopenia, or the reduction in the number of circulating platelets, is one of the more frequent hematologic abnormalities associated with Brucella infection. However, the reasons for this have not yet been studied. In previous studies, we have shown that platelets are capable of establishing complexes with macrophages and neutrophils, which may contribute to the observed thrombocytopenia. Moreover, B. abortus (Ba) can be detected in bone marrow cultures of brucellosis patients. Platelets are formed and released by precursor cells found in the bone marrow, called Megakaryocytes (MKs). This leads us to propose that Brucella could directly affect MK generation (megakaryopoiesis) and/or platelet biogenesis (thrombopoiesis), contributing to the observed thrombocytopenia. On the other hand, we have recently demonstrated that Ba RNA (a PAMP related to pathogens’ viability or vita-PAMP) is involved in macrophage immune-modulation. Therefore, the aim of this study was to evaluate the effect of Ba RNA on megakaryopoiesis and platelet biogenesis. For megakaryopoiesis, hematopoietic progenitor cells purified from human umbilical cord blood (CD34+) were differentiated to MKs with thrombopoietin (TPO) in the presence of different doses of Ba RNA (1, 5 and 10 g/ml) or Heat-Killed Ba (HKBA) (2 x 105 bacteria/l). After 11 days of culture, we determined cell expansion, the expression of the MK differentiation marker CD41 and the MK maturation marker CD42b by flow cytometry. Our results demonstrated that Ba RNA decreased significantly the number of total cells in a dose dependent manner (p