Iron acquisition by Mycobacterium tuberculosis residing within myeloid dendritic cells

Oyebode Olakanmi, Banurekha Kesavalu, Maher Y. Abdalla, Bradley E. Britigan

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

The pathophysiology of Mycobacterium tuberculosis ( M.tb) infection is linked to the ability of the organism to grow within macrophages. Lung myeloid dendritic cells are a newly recognized reservoir of M.tb during infection. Iron (Fe) acquisition is critical for M.tb growth. Invivo, extracellular Fe is chelated to transferrin (TF) and lactoferrin (LF). We previously reported that M.tb replicating in human monocyte-dervied macrophages (MDM) can acquire Fe bound to TF, LF, and citrate, as well as from the MDM cytoplasm. Access of M.tb to Fe may influence its growth in macrophages and dendritic cells. In the present work we confirmed the ability of different strains of M.tb to grow in human myeloid dendritic cells invitro. Fe acquired by M.tb replicating within dendritic cells from externally added Fe chelates varied with the Fe chelate present in the external media: Fe-citrate>Fe-LF>Fe-TF. Fe acquisition rates from each chelate did not vary over 7 days. M.tb within dendritic cells also acquired Fe from the dendritic cell cytoplasm, with the efficiency of Fe acquisition greater from cytoplasmic Fe sources, regardless of the initial Fe chelate from which that cytoplasmic Fe was derived. Growth and Fe acquisition results with human MDM were similar to those with dendritic cells. M.tb grow and replicate within myeloid dendritic cells invitro. Fe metabolism of M.tb growing in either MDM or dendritic cells invitro is influenced by the nature of Fe available and the organism appears to preferentially access cytoplasmic rather than extracellular Fe sources. Whether these invitro data extend to invivo conditions should be examined in future studies.

Original languageEnglish (US)
Pages (from-to)21-28
Number of pages8
JournalMicrobial Pathogenesis
Volume65
DOIs
StatePublished - Dec 1 2013

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Keywords

  • Dendritic cells
  • Iron uptake
  • Mycobacterium tuberculosis

ASJC Scopus subject areas

  • Microbiology
  • Infectious Diseases

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