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Patients with discordant responses to antiretroviral therapy have impaired killing of HIV-infected T cells.

Natesampillai S, Nie Z, Cummins NW, Jochmans D, Bren GD, Angel JB, Badley AD - PLoS Pathog. (2010)

Bottom Line: The reductions in cell death occurred both within infected cells, as well as in uninfected bystander cells.These data indicate that single point mutations within HIV protease which are selected in vivo can significantly impact the ability of HIV to kill CD4 T cells, while not impacting viral replication.Therefore, HIV protease regulates both HIV replication as well as HIV induced T cell depletion, the hallmark of HIV pathogenesis.

View Article: PubMed Central - PubMed

Affiliation: Division of Infectious Diseases, Mayo Clinic, Rochester, MN, USA.

ABSTRACT
In medicine, understanding the pathophysiologic basis of exceptional circumstances has led to an enhanced understanding of biology. We have studied the circumstance of HIV-infected patients in whom antiretroviral therapy results in immunologic benefit, despite virologic failure. In such patients, two protease mutations, I54V and V82A, occur more frequently. Expressing HIV protease containing these mutations resulted in less cell death, caspase activation, and nuclear fragmentation than wild type (WT) HIV protease or HIV protease containing other mutations. The impaired induction of cell death was also associated with impaired cleavage of procaspase 8, a requisite event for HIV protease mediated cell death. Primary CD4 T cells expressing I54V or V82A protease underwent less cell death than with WT or other mutant proteases. Human T cells infected with HIV containing these mutations underwent less cell death and less Casp8p41 production than WT or HIV containing other protease mutations, despite similar degrees of viral replication. The reductions in cell death occurred both within infected cells, as well as in uninfected bystander cells. These data indicate that single point mutations within HIV protease which are selected in vivo can significantly impact the ability of HIV to kill CD4 T cells, while not impacting viral replication. Therefore, HIV protease regulates both HIV replication as well as HIV induced T cell depletion, the hallmark of HIV pathogenesis.

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Related in: MedlinePlus

Discordance Associated Mutations (DAMs) within HIV-1PR alters the generation of TUNEL positivity.YFP HIV protease or the indicated protease point mutants were expressed in HeLa cells, and the YFP positive cells were analyzed for TUNEL positivity (A, B). *Indicates p value ≤0.05. Data reflective of at least three independent replicates. Bars with solid color represent controls, bars with angled hatching represent DAMs, and bars with horizontal hatching represent non-DAMs.
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ppat-1001213-g005: Discordance Associated Mutations (DAMs) within HIV-1PR alters the generation of TUNEL positivity.YFP HIV protease or the indicated protease point mutants were expressed in HeLa cells, and the YFP positive cells were analyzed for TUNEL positivity (A, B). *Indicates p value ≤0.05. Data reflective of at least three independent replicates. Bars with solid color represent controls, bars with angled hatching represent DAMs, and bars with horizontal hatching represent non-DAMs.

Mentions: The putative impairment in cytotoxic activity of I54V and V82A were next assessed by an independent measure of death, generation of active caspase 3, and consequent caspase 3 activity. Consistent with previous findings, WT protease expression generated a significant amount of active caspase 3, and of caspase 3 activity (Figure 4A, 4B, 4C). Mirroring the results of TMRE staining, I54V and V82A had reduced generation of active caspase 3 and caspase 3 activity than WT protease, while K20R, L63P, D30N, L90M, generated similar levels of active caspase 3 and of caspase 3 activity as WT (Figure 4A, 4B, 4C). TUNEL staining confirmed these observations (Figure 5A, 5B) seen with TMRE staining and caspase 3 activity assays; the DAMs I54V, and V82A are associated with reduced induction of cell death compared to WT or the non-DAMs L63P, D30N, L90M, or K20R.


Patients with discordant responses to antiretroviral therapy have impaired killing of HIV-infected T cells.

Natesampillai S, Nie Z, Cummins NW, Jochmans D, Bren GD, Angel JB, Badley AD - PLoS Pathog. (2010)

Discordance Associated Mutations (DAMs) within HIV-1PR alters the generation of TUNEL positivity.YFP HIV protease or the indicated protease point mutants were expressed in HeLa cells, and the YFP positive cells were analyzed for TUNEL positivity (A, B). *Indicates p value ≤0.05. Data reflective of at least three independent replicates. Bars with solid color represent controls, bars with angled hatching represent DAMs, and bars with horizontal hatching represent non-DAMs.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2991267&req=5

ppat-1001213-g005: Discordance Associated Mutations (DAMs) within HIV-1PR alters the generation of TUNEL positivity.YFP HIV protease or the indicated protease point mutants were expressed in HeLa cells, and the YFP positive cells were analyzed for TUNEL positivity (A, B). *Indicates p value ≤0.05. Data reflective of at least three independent replicates. Bars with solid color represent controls, bars with angled hatching represent DAMs, and bars with horizontal hatching represent non-DAMs.
Mentions: The putative impairment in cytotoxic activity of I54V and V82A were next assessed by an independent measure of death, generation of active caspase 3, and consequent caspase 3 activity. Consistent with previous findings, WT protease expression generated a significant amount of active caspase 3, and of caspase 3 activity (Figure 4A, 4B, 4C). Mirroring the results of TMRE staining, I54V and V82A had reduced generation of active caspase 3 and caspase 3 activity than WT protease, while K20R, L63P, D30N, L90M, generated similar levels of active caspase 3 and of caspase 3 activity as WT (Figure 4A, 4B, 4C). TUNEL staining confirmed these observations (Figure 5A, 5B) seen with TMRE staining and caspase 3 activity assays; the DAMs I54V, and V82A are associated with reduced induction of cell death compared to WT or the non-DAMs L63P, D30N, L90M, or K20R.

Bottom Line: The reductions in cell death occurred both within infected cells, as well as in uninfected bystander cells.These data indicate that single point mutations within HIV protease which are selected in vivo can significantly impact the ability of HIV to kill CD4 T cells, while not impacting viral replication.Therefore, HIV protease regulates both HIV replication as well as HIV induced T cell depletion, the hallmark of HIV pathogenesis.

View Article: PubMed Central - PubMed

Affiliation: Division of Infectious Diseases, Mayo Clinic, Rochester, MN, USA.

ABSTRACT
In medicine, understanding the pathophysiologic basis of exceptional circumstances has led to an enhanced understanding of biology. We have studied the circumstance of HIV-infected patients in whom antiretroviral therapy results in immunologic benefit, despite virologic failure. In such patients, two protease mutations, I54V and V82A, occur more frequently. Expressing HIV protease containing these mutations resulted in less cell death, caspase activation, and nuclear fragmentation than wild type (WT) HIV protease or HIV protease containing other mutations. The impaired induction of cell death was also associated with impaired cleavage of procaspase 8, a requisite event for HIV protease mediated cell death. Primary CD4 T cells expressing I54V or V82A protease underwent less cell death than with WT or other mutant proteases. Human T cells infected with HIV containing these mutations underwent less cell death and less Casp8p41 production than WT or HIV containing other protease mutations, despite similar degrees of viral replication. The reductions in cell death occurred both within infected cells, as well as in uninfected bystander cells. These data indicate that single point mutations within HIV protease which are selected in vivo can significantly impact the ability of HIV to kill CD4 T cells, while not impacting viral replication. Therefore, HIV protease regulates both HIV replication as well as HIV induced T cell depletion, the hallmark of HIV pathogenesis.

Show MeSH
Related in: MedlinePlus