TY - JOUR
T1 - Toll-like receptor-3 mediates HIV-1 transactivation via NFκB and JNK pathways and histone acetylation, but prolonged activation suppresses Tat and HIV-1 replication
AU - Bhargavan, Biju
AU - Woollard, Shawna M.
AU - Kanmogne, Georgette D.
N1 - Funding Information:
We would like to thank the NIH AIDS Reagents Program for providing TZM-bl and U38 cells, Ms. Sangya Singh for technical assistance, and Dr. Matthew Omojola for critical reading of the manuscript. This work was partly supported by a grant from the National Institute of Health , National Institute of Mental Health, to G.D.K ( MH081780 and MH094160 ).
PY - 2016/2/1
Y1 - 2016/2/1
N2 - TLR3 has been implicated in the pathogenesis of several viral infections, including SIV- and HIV-1-induced inflammation and AIDS. However the molecular mechanisms of these TLR3-mediated effects are not known, and it is not known whether HIV interacts with cellular TLR3 to affect disease process. Here we investigate the effects of TLR3 ligands on HIV-1 transactivation using both primary human macrophages and cells containing integrated copies of the HIV-1 promoter. We demonstrate that TLR3 activation induced upregulation of transcription factors such as c-Jun, CCAAT/enhancer-binding protein alpha (CEBPA), signal transducer and activator of transcription (STAT)-1, STAT-2, RELB, and nuclear factor kappa-B1 (NFκB1), most of which are known to regulate the HIV promoter activity. We also demonstrate that TLR3 activation increased HIV-1 transactivation via the c-Jun N-terminal kinase (JNK) and NFκB pathways. This was associated with epigenetic modifications, including decreased histone deacetylase activity, increased histone acetyl transferase (HAT) activity, and increased acetylation of histones H3 and H4 at lysine residues in the nucleosome-0 and nucleosome-1 of the HIV-1 promoter. However, prolonged TLR3 activation decreased HIV-1 transactivation, decreased HAT activity and Tat transcription, and suppressed viral replication. Overall, data suggests that TLR3 can act as viral sensor to mediate viral transactivation, cellular signaling, innate immune response, and inflammation in HIV-infected humans. Our study provides novel insights into the molecular basis for these TLR3-mediated effects.
AB - TLR3 has been implicated in the pathogenesis of several viral infections, including SIV- and HIV-1-induced inflammation and AIDS. However the molecular mechanisms of these TLR3-mediated effects are not known, and it is not known whether HIV interacts with cellular TLR3 to affect disease process. Here we investigate the effects of TLR3 ligands on HIV-1 transactivation using both primary human macrophages and cells containing integrated copies of the HIV-1 promoter. We demonstrate that TLR3 activation induced upregulation of transcription factors such as c-Jun, CCAAT/enhancer-binding protein alpha (CEBPA), signal transducer and activator of transcription (STAT)-1, STAT-2, RELB, and nuclear factor kappa-B1 (NFκB1), most of which are known to regulate the HIV promoter activity. We also demonstrate that TLR3 activation increased HIV-1 transactivation via the c-Jun N-terminal kinase (JNK) and NFκB pathways. This was associated with epigenetic modifications, including decreased histone deacetylase activity, increased histone acetyl transferase (HAT) activity, and increased acetylation of histones H3 and H4 at lysine residues in the nucleosome-0 and nucleosome-1 of the HIV-1 promoter. However, prolonged TLR3 activation decreased HIV-1 transactivation, decreased HAT activity and Tat transcription, and suppressed viral replication. Overall, data suggests that TLR3 can act as viral sensor to mediate viral transactivation, cellular signaling, innate immune response, and inflammation in HIV-infected humans. Our study provides novel insights into the molecular basis for these TLR3-mediated effects.
KW - Epigenetics
KW - HIV
KW - Histone acetylation
KW - Human monocyte-derived macrophages
KW - JNK
KW - LTR
KW - NFκB
KW - STAT1
KW - TLR3
KW - TZM-bl
KW - U38 cells
KW - Viral transactivation
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UR - http://www.scopus.com/inward/citedby.url?scp=84947722822&partnerID=8YFLogxK
U2 - 10.1016/j.cellsig.2015.11.005
DO - 10.1016/j.cellsig.2015.11.005
M3 - Article
C2 - 26569339
AN - SCOPUS:84947722822
SN - 0898-6568
VL - 28
SP - 7
EP - 22
JO - Cellular Signalling
JF - Cellular Signalling
IS - 2
ER -