Apresentao do PowerPoint

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Effects of HIV-1 Tat Protein on Trypanosomatid
Replication in HIV-1-Infected Macrophages
Dumith Chequer Bou-Habib Oswaldo Cruz Institute
Fiocruz Rio de Janeiro, RJ Brazil
XVII International AIDS Conference Mexico City,
August 2008
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WHO, 2003
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1911 Leishmania/HIV co-infection cases reported
in south-western Europe by early 2001
(Desjeux Alvar, 2003)
Brazil 326 cases of HIV/Leishmania co-infection
cases from 2000 to 2006, 2 of visceral
leishmaniasis reported in the country (SINAN)
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Some clinical and laboratory findings of
HIV-1/Leishmania co-infected patients

• Diffuse cutaneous leishmaniasis due to parasitic
  dissemination (ulcers containing parasites)
• Chronic progress and relapses of leishmaniasis
• Increased replication of HIV-1 and Leishmania
• High levels of serum cytokines (IL-4, IL-6,
  IL-10)
• Decreased IFN-? levels

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At the cellular level
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(No Transcript)
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HIV-1 Genome

TGF-b
Adapted from Wahl et al. (2003). J Leukoc Biol
74726-735
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Model HIV-1-infected Macrophages Leishmania
Evaluation of Leishmania Infection Endocytic
Index of Leishmania-infected Macrophages X
Mean of Parasites per Cell
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Replication of both pathogens is augmented in
HIV-1/Leishmania co-infected macrophages
plt0.0001 plt0.04
Barreto-de-Souza et al. (2006)
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HIV-1-mediated enhancement of Leishmania growth
is inhibited by anti-Tat antibody
plt0.025
plt0.025
Barreto-de-Souza et al. 2006.
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Purified HIV-1 Tat augments Leishmania
replication in macrophages
plt0.001
Barreto-de-Souza et al. 2006.
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HIV-1 Tat inhibits leishmanicidal effect induced
by IFN-?
plt0.035
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TGF-?1 is partially responsible for the
enhancement of Leishmania growth mediated by Tat
plt0.03
Recombinant Tat induced TGF-b1 secretion by
uninfected macrophages (plt0.002 )
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Tat induces the expression of COX-2 enzyme and
PGE2 synthesis in human macrophages
COX-2
b-actin
0.7160.03 1.3870.23 (ng/mL)
Recombinant Tat was LPS free (lt 0.15 EU/mg)
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Inhibition of the enzyme COX-2 reverts Tat
effect on Leishmania growth
plt0.02
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Inhibition of TGF-?1 abolishes PGE2 effect on
Leishmania growth
plt0.03
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Conclusions

• Tat exacerbates Leishmania growth in
  macrophages co-infected with HIV-1, or infected
  only with Leishmania
• Tat effects on Leishmania replication are
  mediated by
• - Induction of COX-2 and subsequent PGE2
  production
• - Induction of TGF-b1 secretion (probably via
  PGE2)
• - Inhibition of leishmanicidal effect induced
  by IFN-?

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HIV-1 Genome

TGF-b
Adapted from Wahl et al., 2003.
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At the cellular level
Work in progress
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Next question
Could HIV-1 infection deactivate the natural
microbicidal activity of human macrophages? (Lead
ing to an establishment/growth of a
non-pathogenic protozoan?)
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Reports of AIDS patients presenting
Leishmania-like infection caused by otherwise
non-pathogenic trypanosomatids
AIDS patient with a visceral lesions caused by
Leptomonas pulexsimulantis (Pacheco RS et al.,
1998). AIDS patients infected by non-pathogenic
trypanosomatids have been reported since the 80s
(Chicharro C Alvar J, 2003).

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Blastocrithidia culicis as a model for
HIV-co-pathogen studies

• Monoxenic trypanosomatid (entire life cycle
  limited to one host- hematophagous insects)
• Endosymbiont-bearing trypanosomatid, containing a
  single bacterium/protozoan cell.
• Normal human macrophages usually kill
  Blastocrithidia in few days (Barreto-de-Souza et
  al., 2008)
• Some monoxenic protozoa were detected in AIDS
  patients (mainly Herpetomonas and Crithidia)

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Replication of both agents is augmented in
Blastocrithidia/HIV-1 co-infected macrophages
plt0.04 plt0.01
Barreto-de-Souza et al., 2008
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HIV-1 infected Macrophage harboring B.culicis
cells
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Dividing forms of the protozoan in
Blastocrithidia/HIV-1 co-infected macrophages
Barreto-de-Souza et al., 2008
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Neutralization of Tat reduces B. culicis growth
in HIV-1 co-infected macrophages
Barreto-de-Souza et al. 2008
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rTat promotes Blastocrithidia growth in
macrophages
plt 0.05
Barreto-de-Souza et al. 2008
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The increment of B.culicis growth is mediated by
Tat-induced TGF-?1
plt0.05
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Acknowledgments

• Oswaldo Cruz Institute/Fiocruz
• Dept. Immunology
• Victor Barreto de Souza
• Thalyta Medeiros
• Dept. Physiology, Pharmacodinamics
• Adriana R. Silva
• Patrícia T. Bozza
• Hugo C. Castro Faria-Neto

• Federal University of
• Rio de Janeiro
• Dept. Immunology, IMPPG
• Elvira Saraiva
• Graziela J. Pacheco
• Biophysics Institute, IBCCF
• Cristina Motta

• Reagents NIH AIDS Reagent Program,
  Hemotherapy Service (HUCCF - UFRJ)

Financial Support Papes/Fiocruz, CNPq, Faperj