Journal article
Leishmania donovani Ornithine Decarboxylase Is Indispensable for Parasite Survival in the Mammalian Host
Infection and immunity, Vol.77(2), pp.756-763
02/2009
DOI: 10.1128/IAI.01236-08
PMCID: PMC2632046
PMID: 19064633
Abstract
Mutations within the polyamine biosynthetic pathway of
Leishmania donovani
, the etiological agent of visceral leishmaniasis, confer polyamine auxotrophy to the insect vector or promastigote form of the parasite. However, whether the infectious or amastigote form of the parasite requires an intact polyamine pathway has remained an open question. To address this issue, conditionally lethal Δ
odc
mutants lacking ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine biosynthesis, were created by double targeted gene replacement within a virulent strain of
L. donovani
. ODC-deficient promastigotes and axenic amastigotes were auxotrophic for polyamines and capable of robust growth only when exogenous putrescine was supplied in the culture medium, confirming that polyamine biosynthesis is an essential nutritional pathway for
L. donovani
promastigotes. To assess whether the Δ
odc
lesion also affected the ability of amastigotes to sustain a robust infection, macrophage and mouse infectivity experiments were performed. Parasite loads in murine macrophages infected with each of two independent Δ
odc
knockout lines were decreased ∼80% compared to their wild-type counterpart. Furthermore, α-difluoromethylornithine, a suicide inhibitor of ODC, inhibited growth of wild-type
L. donovani
amastigotes and effectively cured macrophages of parasites, thereby preventing host cell destruction. Strikingly, however, parasitemias of both Δ
odc
null mutants were reduced by 6 and 3 orders of magnitude, respectively, in livers and spleens of BALB/c mice. The compromised infectivity phenotypes of the Δ
odc
knockouts in both macrophages and mice were rescued by episomal complementation of the genetic lesion. These genetic and pharmacological studies strongly implicate ODC as an essential cellular determinant that is necessary for the viability and growth of both
L. donovani
promastigotes and amastigotes and intimate that pharmacological inhibition of ODC is a promising therapeutic paradigm for the treatment of visceral and perhaps other forms of leishmaniasis.
Details
- Title: Subtitle
- Leishmania donovani Ornithine Decarboxylase Is Indispensable for Parasite Survival in the Mammalian Host
- Creators
- Jan M Boitz - Department of Microbiology, University of Iowa, Iowa City, Iowa 52242Phillip A Yates - Department of Microbiology, University of Iowa, Iowa City, Iowa 52242Chelsey Kline - Department of Microbiology, University of Iowa, Iowa City, Iowa 52242Upasna Gaur - Department of Microbiology, University of Iowa, Iowa City, Iowa 52242Mary E Wilson - Department of Microbiology, University of Iowa, Iowa City, Iowa 52242Buddy Ullman - Department of Microbiology, University of Iowa, Iowa City, Iowa 52242Sigrid C Roberts - Department of Microbiology, University of Iowa, Iowa City, Iowa 52242
- Resource Type
- Journal article
- Publication Details
- Infection and immunity, Vol.77(2), pp.756-763
- Publisher
- American Society for Microbiology (ASM)
- DOI
- 10.1128/IAI.01236-08
- PMID
- 19064633
- PMCID
- PMC2632046
- ISSN
- 0019-9567
- eISSN
- 1098-5522
- Language
- English
- Date published
- 02/2009
- Academic Unit
- Microbiology and Immunology; International Programs; Epidemiology; Internal Medicine
- Record Identifier
- 9984001200902771
Metrics
12 Record Views