Inhibition of NF-κB and HIV-1 Long Terminal Repeat Transcriptional Activation by Inducible Nitric Oxide Synthase 2 Activity

Abstract

In the human lymphoblastoid T cell line JJhan-5.1, stably transfected with a human immunodeficiency virus-1 long terminal repeat luciferase vector, the level of luciferase activity is dependent on activation of the nuclear factor B (NF-B) transcription factor. Tumor necrosis factor-induced luciferase activity was not modified in JJhan-5.1 cells co-cultivated with murine adenocarcinoma EMT-6 cells but was strongly decreased when nitric oxide (NO) synthase 2 expression was induced in these cells. Two NO synthase inhibitors counteracted this inhibitory effect. Tumor necrosis factor-␣ binding to JJhan-5.1 cells was not modified after incubation with EMT-6 cells. Viability and protein synthesis in JJhan-5.1 cells were also unchanged. Induction of NF-B DNA binding activity was inhibited when EMT-6 cells expressed NO synthase 2 activity. Aminoguanidine, which completely abolished nitrite production, prevented this inhibition. NF-B activation was also strongly inhibited by S-nitrosoglutathione but was marginally affected by N-(2-aminoethyl)-N-(2-hydroxy-2-nitrosohydrazino)-1,2-ethylenediamine. Taken together, these results indicated that NO-related species, released by EMT-6 effector cells and probably different from NO itself, inhibited NF-B activation in human lymphoblastoid target cells. Consequently, transcriptional activity of a long terminal repeat-driven luciferase gene construct was markedly diminished.

Regulation of Human Immunodeficiency Virus Type 1 Replication in Human T Lymphocytes by Nitric Oxide

“…In general, low concentrations of NO donors or NO gas are sufficient to activate NF-B (35). On the other hand, high NO output rates, 2 to 4 M NO2 Ϫ /h, were found to be inhibitory (58). In agreement with that hypothesis, the two NO donors used in our studies, SNAP and SNP, have been previously shown to activate NF-B in T cells (35).…”

“…At those concentrations, no effect on cell proliferation or cell survival was observed. In contrast, others have shown that high concentrations of NO (as those supplied by GSNO) inhibit NF-B activation (13,51,58) and HIV-1 replication (39). At those concentrations, NO has been shown to reduce cell proliferation and to cause apoptosis (3,65).…”

Expressions of Nuclear Factor κB, Inducible Nitric Oxide Synthase, and Vascular Endothelial Growth Factor in Adenoid Cystic Carcinoma of Salivary Glands: Correlations with the Angiogenesis and Clinical Outcome

“…However, resent researches indicated that NO also played a contradictive role in NF-nB activation, depending on the experimental conditions. The iNOS activity inhibits NF-nB activation in T cells (42) and the NO donors such as sodium nitroprusside and nitrosoglutathione inhibits NF-nB activity in a mouse embryonic carcinoma (43). In contrast, increasing evidence shows that the NF-nB activity and NO generation as a result of iNOS can make a positive regulatory loop.…”

Activation of apoptotic caspase‐3 and nitric oxide synthase‐2 in buccal mucosa with chronic alcohol ingestion

“…There are indications that enhanced expression of NOS-2 leads not only to NO production, but also results in the formation of NO-related species such as nitrosothiols, preoxynitrite, and dinitrosyl ion complexes which exert a direct inhibitory effect on NF-KB (8), and hence cause transcriptional disturbances that lead to apoptosis (7,13). Indeed, the apoptotic death pathway linked to overexpression of NOS-2 is characterized by a such typical apoptotic events as chromatin condensation, blebbing of cytoplasmic membranes, and DNA laddering (12,23).…”

“…Nitric oxide is a ubiquitous cell-permeable signaling molecule generated from L-arginine by three calmodulin-dependent nitric oxide synthase (NOS) isozymes that are functionally distinguished by their modes of action (8,11).…”