Resumo:
Background: Cutaneous leishmaniasis (CL) is characterized by the presence of
skin-ulcerated lesions. CL lesions present high levels of TNF and IL-1β increased
frequency of lymphocytes and mononuclear phagocytes and few parasites. Annexin
A1 (ANXA1) is a protein belonging to the calcium-dependent phospholipid-binding
annexin’s superfamilies that is induced by glucocorticoids and are capable of
regulating the production of inflammatory mediators. The anti-inflammatory effects of
ANXA1 are mediated for the most part through binding to the formyl peptide receptor
2 (FPR2) resulting in control of the inflammatory response. Our aim was to evaluate
the influence of ANXA1 in IL-1β production by L. braziliensis-infected macrophages.
Materials and Methods: Skin biopsies, whole blood and serum were obtained from
CL patients and healthy subjects (HS). Gene expression (IL1B, ANXA1, FPR2,
NLRP3, CASP1 and PYCARD) were determined by RNAseq in skin biopsies and
whole blood. Monocyte-derived macrophages from HS were infected with L.
braziliensis (in a 5:1 ratio) in presence or absence of rANXA1 or WRW4 (Selective
FPR2 receptor inhibitor) and cultured for 4 and 48h. Levels of ANXA1 and IL-1B
where determined in serum and supernatants of culture. Results: We observed that
the genes described above were increased in CL lesions. We also observed that
genes from NLRP3 inflammasome pathway were positively correlated with FPR2
and ANXA1 at lesion, while in blood only the NLRP3 gene was negatively correlated
with ANXA1. In addition, we found that CL patients presented higher serum levels of
ANXA1 and IL-1β when compared to HS. Leishmania-infected macrophages
produced high levels of ANXA1 and IL-1β. Finally, we found that enrichment of
ANXA1-infected macrophage cultures decreased IL-1β levels without altering the
parasite load. Conclusion: Our results suggest that the increase in ANXA1
downregulates IL-1β production without affecting the ability of macrophages to kill L.
braziliensis.
