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Leishmania major lacking arginase (ARG) are auxotrophic for polyamines but retain infectivity to susceptible BALB/c mice.
Mol Biochem Parasitol. 2009 May; 165(1):48-56.MB

Abstract

Polyamines are essential metabolites in eukaryotes participating in a variety of proliferative processes, and in trypanosomatid protozoa play an additional role in the synthesis of the critical thiol trypanothione. Whereas the polyamine biosynthesis arising from L-ornithine has been well studied in protozoa, the metabolic origin(s) of L-ornithine have received less attention. Arginase (EC 3.5.3.1) catalyzes the enzymatic hydrolysis of L-arginine to L-ornithine and urea, and we tested the role of arginase in polyamine synthesis by the generation of an arg(?) knockout in Leishmania major by double targeted gene replacement. This mutant lacked arginase activity and required the nutritional provision of polyamines or L-ornithine for growth. A complemented line (arg(?)/+ARG) expressing arginase from a multi-copy expression vector showed 30-fold elevation of arginase activity, similar polyamine and ornithine levels as the wild-type, and resistance to the inhibitors ?-difluoromethylornithine (DFMO) and N(?)-hydroxy-l-arginine (NOHA). This established that arginase is the major route of polyamine synthesis in promastigotes cultured in vitro. The arg(?) parasites retained the ability to differentiate normally to the infective metacyclic stage, and were able to induce progressive disease following inoculation into susceptible BALB/c mice, albeit less efficiently than WT parasites. These data suggest that the infective amastigote form of Leishmania, which normally resides within an acidified parasitophorous vacuole, can survive in vivo through salvage of host polyamines and/or other molecules, aided by the tendency of acidic compartments to concentrate basic metabolites. This may thus contribute to the relative resistance of Leishmania to ornithine decarboxylase (ODC) inhibitors. The availability of infective, viable, arginase-deficient parasites should prove useful in dissecting the role of l-arginine metabolism in both pro- and anti-parasitic responses involving host nitric oxide synthase, which requires L-arginine to generate NO.

Authors+Show Affiliations

Departamento de Ciencias Biomédicas, Facultad de Veterinaria, Universidad de León. Campus de Vegazana s/n 24071-León, Spain.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19393161

Citation

Reguera, Rosa M., et al. "Leishmania Major Lacking Arginase (ARG) Are Auxotrophic for Polyamines but Retain Infectivity to Susceptible BALB/c Mice." Molecular and Biochemical Parasitology, vol. 165, no. 1, 2009, pp. 48-56.
Reguera RM, Balaña-Fouce R, Showalter M, et al. Leishmania major lacking arginase (ARG) are auxotrophic for polyamines but retain infectivity to susceptible BALB/c mice. Mol Biochem Parasitol. 2009;165(1):48-56.
Reguera, R. M., Balaña-Fouce, R., Showalter, M., Hickerson, S., & Beverley, S. M. (2009). Leishmania major lacking arginase (ARG) are auxotrophic for polyamines but retain infectivity to susceptible BALB/c mice. Molecular and Biochemical Parasitology, 165(1), 48-56. https://doi.org/10.1016/j.molbiopara.2009.01.001
Reguera RM, et al. Leishmania Major Lacking Arginase (ARG) Are Auxotrophic for Polyamines but Retain Infectivity to Susceptible BALB/c Mice. Mol Biochem Parasitol. 2009;165(1):48-56. PubMed PMID: 19393161.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Leishmania major lacking arginase (ARG) are auxotrophic for polyamines but retain infectivity to susceptible BALB/c mice. AU - Reguera,Rosa M, AU - Balaña-Fouce,Rafael, AU - Showalter,Melissa, AU - Hickerson,Suzanne, AU - Beverley,Stephen M, Y1 - 2009/01/20/ PY - 2008/11/26/received PY - 2009/01/05/revised PY - 2009/01/12/accepted PY - 2009/4/28/entrez PY - 2009/4/28/pubmed PY - 2009/5/13/medline SP - 48 EP - 56 JF - Molecular and biochemical parasitology JO - Mol Biochem Parasitol VL - 165 IS - 1 N2 - Polyamines are essential metabolites in eukaryotes participating in a variety of proliferative processes, and in trypanosomatid protozoa play an additional role in the synthesis of the critical thiol trypanothione. Whereas the polyamine biosynthesis arising from L-ornithine has been well studied in protozoa, the metabolic origin(s) of L-ornithine have received less attention. Arginase (EC 3.5.3.1) catalyzes the enzymatic hydrolysis of L-arginine to L-ornithine and urea, and we tested the role of arginase in polyamine synthesis by the generation of an arg(?) knockout in Leishmania major by double targeted gene replacement. This mutant lacked arginase activity and required the nutritional provision of polyamines or L-ornithine for growth. A complemented line (arg(?)/+ARG) expressing arginase from a multi-copy expression vector showed 30-fold elevation of arginase activity, similar polyamine and ornithine levels as the wild-type, and resistance to the inhibitors ?-difluoromethylornithine (DFMO) and N(?)-hydroxy-l-arginine (NOHA). This established that arginase is the major route of polyamine synthesis in promastigotes cultured in vitro. The arg(?) parasites retained the ability to differentiate normally to the infective metacyclic stage, and were able to induce progressive disease following inoculation into susceptible BALB/c mice, albeit less efficiently than WT parasites. These data suggest that the infective amastigote form of Leishmania, which normally resides within an acidified parasitophorous vacuole, can survive in vivo through salvage of host polyamines and/or other molecules, aided by the tendency of acidic compartments to concentrate basic metabolites. This may thus contribute to the relative resistance of Leishmania to ornithine decarboxylase (ODC) inhibitors. The availability of infective, viable, arginase-deficient parasites should prove useful in dissecting the role of l-arginine metabolism in both pro- and anti-parasitic responses involving host nitric oxide synthase, which requires L-arginine to generate NO. SN - 0166-6851 UR - https://www.unboundmedicine.com/medline/citation/19393161/Leishmania_major_lacking_arginase__ARG__are_auxotrophic_for_polyamines_but_retain_infectivity_to_susceptible_BALB/c_mice_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0166-6851(09)00007-3 DB - PRIME DP - Unbound Medicine ER -