School of Medicine and Health Sciences Poster Presentations

DNA-PK Inhibition Potently Represses HIV Transcription and Replication

Poster Number

252

Document Type

Poster

Publication Date

3-2016

Abstract

DNA-dependent protein kinase (DNA-PK), a nuclear protein kinase that specifically requires association with DNA for its kinase activity, plays important roles in the regulation of different DNA transactions, including transcription, replication and DNA repair, as well as in the maintenance of telomeres. We reported DNA-PK facilitated HIV transcription by interacting with the RNA polymerase II (RNAP II) complex recruited to HIV LTR and identified potential DNA-PK targets within the carboxyl terminal domain (CTD) of RNAP II through kinase assays. In our current study, DNA-PK inhibition via highly specific small molecule inhibitors replicated the shRNA-mediated abrogation of both HIV transcription and replication in latently infected myeloid and lymphoid cell lines, the main cell types targeted by HIV. These inhibitors also impaired HIV replication in primary CD4+ T-cells. Pre-treatment of the HIV-infected cell lines with the DNA-PK inhibitors also resulted in severe impairment of the phosphorylation of the serine 2 and serine 5 of the RNAP II CTD upon stimulation. Chromatin immunoprecipitation (ChIP) analysis showed the inhibition of DNA-PK activity led to the establishment of transcriptionally repressive heterochromatin structures at the HIV LTR. These findings confirm the important role of DNA-PK in HIV transcription and replication and excitingly we have identified two strong inhibitors of DNA-PK that successfully limit the reactivation of latently HIV-infected cells. In light of the fact that these transcriptionally silent proviruses are well protected from both the immune system and HAART regimens, which prevents complete eradication of the virus, we present strong evidence for the inclusion of DNA-PK inhibitors as supplements to HAART regimens, to enhance their restriction of HIV replication.

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This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

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Presented at: GW Research Days 2016

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DNA-PK Inhibition Potently Represses HIV Transcription and Replication

DNA-dependent protein kinase (DNA-PK), a nuclear protein kinase that specifically requires association with DNA for its kinase activity, plays important roles in the regulation of different DNA transactions, including transcription, replication and DNA repair, as well as in the maintenance of telomeres. We reported DNA-PK facilitated HIV transcription by interacting with the RNA polymerase II (RNAP II) complex recruited to HIV LTR and identified potential DNA-PK targets within the carboxyl terminal domain (CTD) of RNAP II through kinase assays. In our current study, DNA-PK inhibition via highly specific small molecule inhibitors replicated the shRNA-mediated abrogation of both HIV transcription and replication in latently infected myeloid and lymphoid cell lines, the main cell types targeted by HIV. These inhibitors also impaired HIV replication in primary CD4+ T-cells. Pre-treatment of the HIV-infected cell lines with the DNA-PK inhibitors also resulted in severe impairment of the phosphorylation of the serine 2 and serine 5 of the RNAP II CTD upon stimulation. Chromatin immunoprecipitation (ChIP) analysis showed the inhibition of DNA-PK activity led to the establishment of transcriptionally repressive heterochromatin structures at the HIV LTR. These findings confirm the important role of DNA-PK in HIV transcription and replication and excitingly we have identified two strong inhibitors of DNA-PK that successfully limit the reactivation of latently HIV-infected cells. In light of the fact that these transcriptionally silent proviruses are well protected from both the immune system and HAART regimens, which prevents complete eradication of the virus, we present strong evidence for the inclusion of DNA-PK inhibitors as supplements to HAART regimens, to enhance their restriction of HIV replication.