Nitric Oxide-Dependent Ribosomal RNA Cleavage Is Associated with Inhibition of Ribosomal Peptidyl Transferase Activity in ANA-1 Murine Macrophages

Abstract

NO can regulate specific cellular functions by altering transcriptional programs and protein reactivity. With respect to global cellular processes, NO has also been demonstrated to inhibit total protein synthesis and cell proliferation. The underlying mechanisms are unknown. In a system of ANA-1 murine macrophages, iNOS expression and NO production were induced by exposure to endotoxin (LPS). In selected instances, cells were exposed to an exogenous NO donor, S-nitroso-N-acetylpenicillamine or a substrate inhibitor of NO synthesis. Cellular exposure to NO, from both endogenous and exogenous sources, was associated with a significant time-dependent decrease in total protein synthesis and cell proliferation. Gene transcription was unaltered. In parallel with decreased protein synthesis, cells exhibited a distinctive cleavage pattern of 28S and 18S rRNA that were the result of two distinct cuts in both 28S and 18S rRNA. Total levels of intact 28S rRNA, 18S rRNA, and the composite 60S ribosome were significantly decreased in the setting of cell exposure to NO. Finally, 60S ribosome-associated peptidyl transferase activity, a key enzyme for peptide chain elongation, was also significantly decreased. Our data suggest that NO-mediated cleavage of 28S and 18S rRNA results in decreased 60S ribosome associated peptidyl transferase activity and inhibition of total protein synthesis.

The Entamoeba histolytica Dnmt2 Homolog (Ehmeth) Confers Resistance to Nitrosative Stress

“…NO plays a major role in this defense process, and NO-induced inhibition of protein synthesis is part of its cytostatic action in mammalian cells. Different mechanisms, such as NOmediated cleavage of 28S and 18S rRNA (42) and NO-induced phosphorylation of eukaryotic initiation factor 2␣ (eIF-2␣) (43) have been proposed to explain this inhibitory activity. Therefore, one might surmise that any action of the parasite to counteract the deleterious effect of NO on its protein synthesis is an effective means of resistance against nitrosative stress.…”

Perinatal Exogenous Nitric Oxide in Fawn-Hooded Hypertensive Rats Reduces Renal Ribosomal Biogenesis in Early Life

“…One exogenous factor that has been shown to affect rDNA and ribosome biogenesis is nitric oxide (NO). Exposure of cells to high levels of NO, using either NO-donors, or inducing expression of inducible NO synthase (iNOS), results in inhibition of the 80S ribosomal complex (Kim et al, 1998) and enhanced rRNA cleavage resulting in a reduction of both 60S and 80S ribosomal particles (Cai et al, 2000). …”

The Peptaibol Alamethicin Induces an rRNA‐Cleavage‐Associated Death in Arabidopsis thaliana

“…One role of the HR is to limit pathogen development by nutrient privation [14]. Nitric oxide (NO), which has been reported as a key regulator of apoptosis in plants and animals [15] [16], induces rRNA cleavage in murine macrophages [17]. Thus, we addressed the question whether or not an NOmediated PCD process associated with rRNA cleavage can be initiated by alamethicin under the conditions tested.…”

“…Depending on the cell system used, NO has been proposed to initiate or propagate PCD during plant hypersensitive response (HR) [22] [23]. In addition, NO induces a specific rRNA cleavage in murine macrophages [17]. We have, thus, checked the potential contribution of NO to alamethicin-promoted rRNA cleavage.…”