Strategies of Intracellular Pathogens for Obtaining Iron from the Environment

Abstract

Most microorganisms are destroyed by the host tissues through processes that usually involve phagocytosis and lysosomal disruption. However, some organisms, called intracellular pathogens, are capable of avoiding destruction by growing inside macrophages or other cells. During infection with intracellular pathogenic microorganisms, the element iron is required by both the host cell and the pathogen that inhabits the host cell. This minireview focuses on how intracellular pathogens use multiple strategies to obtain nutritional iron from the intracellular environment in order to use this element for replication. Additionally, the implications of these mechanisms for iron acquisition in the pathogen-host relationship are discussed.

Comparative Genomics of Sibling Species of Fonsecaea Associated with Human Chromoblastomycosis

“…Most fungi are able to produce and utilize intracellular siderophores as an iron storage compound (Eisendle et al, 2006 ). In Candida albicans siderophore transporter-defective mutants were clearly compromised in invading keratinocyte layers suggesting that siderophore uptake is required to epithelial invasion and penetration (Leon-Sicairos et al, 2015 ). The clinical species C. carrionii and F. pedrosoi show gene enrichment in cellular response to siderophore biosynthetic process and ferric triacetylfusarinine C transport which might play a role in virulence of these agents, as these genes were not enriched in the environmental species (Table S4 ).…”

Iron Metabolism and the Inflammatory Response

“…In keeping with this notion, FPN overexpression was shown to inhibit the growth of intracellular pathogens, e.g. M. tuberculosis and Salmonella enterica , within macrophages , presumably via a mechanism that cause Fe nutrient deprivation. Inhibition of lysosomal fusion and destruction of phagosomal membranes are used by microbes to avoid the action of catalytic enzymes.…”

Iron trafficking in patients with Indian Post kala-azar dermal leishmaniasis

“…NRAMP-2 is a symporter of H + and metal ions, and under physiological conditions is localized in the early endosomal membranes where it is responsible for delivery of extracellularly acquired bivalent cations into the cytosol [36]. Intracellular organisms like Francisella tularensis upregulate DMT-1 expression [37] and similarly, at lesional sites of PKDL cases, the increased mRNA expression of DMT-1 endorsed its possible utilization by parasites to enhance influx of iron (Fig 1E). However, in VL, an unaltered expression of DMT-1 was observed, and could be attributed to it being an acute disease vis-a-vis the chronicity of PKDL [31].…”