title: Leishmania HASP and SHERP Genes Are Required for In Vivo Differentiation, Parasite Transmission and Virulence Attenuation in the Host.
abstract: Differentiation of extracellular Leishmania promastigotes within their sand fly vector, termed metacyclogenesis, is considered to be essential for parasites to regain mammalian host infectivity. Metacyclogenesis is accompanied by changes in the local parasite environment, including secretion of complex glycoconjugates within the promastigote secretory gel and colonization and degradation of the sand fly stomodeal valve. Deletion of the stage-regulated HASP and SHERP genes on chromosome 23 of Leishmania major is known to stall metacyclogenesis in the sand fly but not in in vitro culture. Here, parasite mutants deficient in specific genes within the HASP/SHERP chromosomal region have been used to investigate their role in metacyclogenesis, parasite transmission and establishment of infection. Metacyclogenesis was stalled in HASP/SHERP mutants in vivo and, although still capable of osmotaxis, these mutants failed to secrete promastigote secretory gel, correlating with a lack of parasite accumulation in the thoracic midgut and failure to colonise the stomodeal valve. These defects prevented parasite transmission to a new mammalian host. Sand fly midgut homogenates modulated parasite behaviour in vitro, suggesting a role for molecular interactions between parasite and vector in Leishmania development within the sand fly. For the first time, stage-regulated expression of the small HASPA proteins in Leishmania (Leishmania) has been demonstrated: HASPA2 is expressed only in extracellular promastigotes and HASPA1 only in intracellular amastigotes. Despite its lack of expression in amastigotes, replacement of HASPA2 into the null locus background delays onset of pathology in BALB/c mice. This HASPA2-dependent effect is reversed by HASPA1 gene addition, suggesting that the HASPAs may have a role in host immunomodulation.
authors.affiliation: Centre for Immunology and Infection, Department of Biology, University of York, York, United Kingdom.
authors.forename: Johannes S P
authors.initials: JS
authors.lastname: Doehl
authors.affiliation: Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic.
authors.forename: Jovana
authors.initials: J
authors.lastname: Sádlová
authors.affiliation: Vector Molecular Biology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America.
authors.forename: Hamide
authors.initials: H
authors.lastname: Aslan
authors.affiliation: Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic.
authors.forename: Kateřina
authors.initials: K
authors.lastname: Pružinová
authors.affiliation: Vector Molecular Biology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America.
authors.forename: Sonia
authors.identifier: 0000-0002-5210-6857
authors.initials: S
authors.lastname: Metangmo
authors.affiliation: Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Votýpka
authors.affiliation: Vector Molecular Biology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America.
authors.forename: Shaden
authors.initials: S
authors.lastname: Kamhawi
authors.affiliation: Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Volf
authors.affiliation: Centre for Immunology and Infection, Department of Biology, University of York, York, United Kingdom.
authors.forename: Deborah F
authors.identifier: 0000-0002-8082-5162
authors.initials: DF
authors.lastname: Smith
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology; D004195:Disease Models, Animal; D005455:Fluorescent Antibody Technique; D006790:Host-Parasite Interactions / Q000502:physiology*; D015151:Immunoblotting; D007303:Insect Vectors / Q000469:parasitology; D018320:Leishmania major / Q000254:growth & development / Q000472:pathogenicity*; D007896:Leishmaniasis / Q000235:genetics / Q000635:transmission*; D051379:Mice; D008807:Mice, Inbred BALB C; D016133:Polymerase Chain Reaction; D015800:Protozoan Proteins / Q000378:metabolism*; D011576:Psychodidae / Q000469:parasitology; D014774:Virulence / Q000502:physiology*
chemical_list: D000953:Antigens, Protozoan; C401882:HASPA protein, Leishmania; D015800:Protozoan Proteins