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Indoleamine 2,3-dioxygenase and iron are required for Mycobacterium leprae survival.


Our previous study has demonstrated that IL-10 may modulate both indoleamine 2,3-dioxygenase (IDO) and CD163 expression in lepromatous leprosy (LL) cells, favoring Mycobacterium leprae persistence through induction of regulatory pathways and iron storage. Here, we observed that in LL lesion cells there is an increase in the expression of proteins involved in iron metabolism such as hemoglobin (Hb), haptoglobin, heme oxygenase 1 and transferrin receptor 1 (TfR1) when compared to tuberculoid leprosy (BT) cells. We also found increased iron deposits and diminished expression of the iron exporter ferroportin 1 in LL lesion cells. Hemin, but not FeSO4 stimulation, was able to enhance M. leprae viability by a mechanism that involves IDO. Analysis of cell phenotype in lesions demonstrated a predominance of M2 markers in LL when compared with BT lesion cells. A positive correlation between CD163 and PPARG with the baciloscopic index (BI) was observed. In contrast, TNF, STAT1 and CSF2 presented a negative correlation with the BI. In summary, this study demonstrates that iron may regulate IDO expression by a mechanism that involves IL-10, which may contribute for the predominance of M2-like phenotype in LL lesions that favors the phagocytosis and maintenance of M. leprae in host cells.

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Journal Article
Mattos Barbosa MG
Silva Prata RB
Andrade PR
Ferreira H
Andrade Silva BJ
Paixão de Oliveira JA
Assis TQ
Toledo-Pinto TG
Lima Bezerra OC
Costa Nery JA
Rosa PS
Bozza MT
Lara FA
Moraes MO
Schmitz V
Sarno EN
Pinheiro RO
Year of Publication
Microbes and infection
ISSN Number
Alternate Journal
Microbes Infect.
Publication Language