Prostaglandin E2 Up-regulates HIV-1 Long Terminal Repeat-driven Gene Activity in T Cells via NF-κB-dependent and -Independent Signaling Pathways

Emerging Roles of Prostaglandins in HIV-1 Transcription

“…Only exogeneous PGE 2 plays a role in the activation of HIV-1 LTR-driven gene expression as shown with experiments using indomethacin, a potent inhibitor of the cyclooxygenase pathway (Dumais et al, 1998). Moreover, it was demonstrated that T cells had a limited capacity to metabolize arachidonic acid to prostaglandins (Auberger et al, 1989;Fu et al, 1990;Goldyne & Rea, 1987).…”

“…Interaction between PGE 2 and an adenylate cyclase-coupled stimulatory receptor leads to activation of adenylate cyclase, hydrolysis of ATP, enhanced turnover of intracellular cAMP and binding to PKA (Kammer, 1988). In T cells, PGE 2 -induced enhancement of HIV-1 LTR dependent activity requires the participation of adenylate cyclase, cAMP as well as protein kinase A (Dumais et al, 1998) and elevation of cAMP levels resulted in HIV-1 replication (Nokta & Pollard, 1992). It is also well known that cAMP-dependent pathways regulate the immune effector functions of lymphocytes and macrophages.…”

“…Northern blot assays, flow cytometric analyses, and pharmacological studies showed that the EP 4 gene is expressed on T lymphoid cells such as Molt-4, KM-3, IG5 and Jurkat E6.1 (Blaschke et al, 1996;De Vries et al, 1995;Dumais et al, 1998;Mori et al, 1996). It has been demonstrated that EP 4 receptors are coupled to adenylate cyclase via a stimulatory G protein (G s ) and that such activation results in an enhancement of intracellular cAMP levels (Coleman et al, 1995;Nishigaki et al, 1995).…”

Nf-κb-Dependent Inhibition of HIV-1 Transcription by Withaferin A

“…In order to assess whether WA can modulate HIV-1 LTR activity, 1G5 cells or Jurkat E6.1 cells (5×10 5 ) transfected with different reporter plasmids were either left untreated or treated with PMA/ PHA (20 ng/ml and 1 µg/ml, respectively) and 0.5 to 5 µM of WA in a final volume of 200 µl for 8 h at 37°C [21]. Next, 100 µl of cell-free supernatant were withdrawn from each well and 25 µl of cell culture lysis buffer (25 mM Tris phosphate, pH 7.8, 2 mM dithiothreitol, 1% Triton X-100, and 10% glycerol) were added before incubation at room temperature, while vortexing for 30 min.…”

“…Nuclear extracts were prepared as described in [21]. Briefly, Jurkat E6.1 cells (10 6 ) were either left untreated or treated with PMA/PHA (20 ng/ml and 1 µg/ml, respectively) and/or WA (0.5 µM) for the indicated time at 37°C.…”