Insights into the Regulation of TNF-α Production in Human Mononuclear Cells: The Effects of Non-Specific Phosphodiesterase Inhibition

Abstract

Deree J, Martins JO, Melbostad H, Loomis WH, Coimbra R. Insights into the regulation of TNF-α production in human mononuclear cells: the effects of non-specific phosphodiesterase inhibition. Clinics. 2008;63:321-8. OBJECTIVE:The objective of this study was to determine the effect of nonspecific phosphodiesterase inhibition on transcription factor activation and tumor necrosis factor-alpha (TNF-α) production in lipopolysaccharide (LPS)-stimulated human mononuclear cells. INTRODUCTION:The production of TNF-α following LPS stimulation is one of the key steps in bacterial sepsis and inflammation. The mechanism by which phosphodiesterase inhibition alters TNF-α production in the presence of LPS remains unclear. METHODS: Human mononuclear cells were stimulated with LPS (1 µg/mL), in the presence and absence of Pentoxifylline (PTX; 20 mM), a nonspecific phosphodiesterase inhibitor. Western blotting of phosphorylated cytoplasmic I-κBα, nuclear factor-κB p65 (NF-κB), and nuclear cAMP-response element binding protein (CREB) was performed. DNA binding of NF-κB and CREB was verified by electrophoretic mobility shift assay. TNF-α levels were determined in the supernatant of stimulated cells in the presence and absence Protein kinase A inhibition by an enzyme-linked immunosorbent assay (ELISA). RESULTS: PTX was demonstrated to significantly reduce cytoplasmic I-κBα phosphorylation, nuclear p65 phosphorylation, and the DNA binding activity of NF-κB. In contrast, PTX markedly enhanced the phosphorylation and DNA binding activity of CREB. Cells concomitantly treated with PTX and LPS secreted similar levels of TNF-α in the presence and absence Protein kinase A inhibition. DISCUSSION: The increased level of cAMP that results from phosphodiesterase inhibition affects cytoplasmic and nuclear events, resulting in the attenuation of NF-κB and the activation of CREB transcriptional DNA binding through pathways that are partially Protein kinase A-independent. CONCLUSION: PTX-mediated phosphodiesterase inhibition occurs partially through a Protein kinase A-independent pathway and may serve as a useful tool in the attenuation of LPS-induced inflammation.

Pentoxifylline Associated with Other Antioxidants (Multimodal Therapy) on Patients with Peyronie's Disease. Results of a Controlled Study

“…PTX has antioxidant properties and it exerts antifibrotic and anti-inflammatory activity [29][30][31]. PTX is a nonspecific inhibitor of Phosphodiesterase (PDE); this drug inhibits: TGFbeta-1-stimulated collagen deposition [32,33]; transcriptional activity of NF-kB and TNF-alpha release [34,35]. PTX also inhibits proliferation of Tunica Albuginea-Derived Fibroblasts (TADF) and attenuates TGF-β1-mediated collagen production in TADF [33].…”

Hepatitis B virus X protein up-regulates tumor necrosis factor-α expression in cultured mesangial cells via ERKs and NF-κB pathways

“…This allows the transcription factor to bind to promoter regions of specific pro-inflammatory genes and influence transcription. Because a number of potential κB sites are present in the nucleotide sequences of the TNF-α gene, NF-κB is considered to be a critical transcriptional factor involved in TNF-α gene expression and protein synthesis [28] .…”

Pentoxifylline Induces Lipolysis and Apoptosis of Human Preadipocytes, Keratinocytes and Fibroblasts In Vitro

“…opolysaccharide stimulated peripheral blood mononuclear cells (Coimbra et al, 2005;Deree et al, 2008). The currently available PTX concentration in Korea is 73 mM.…”