Overview: Cardiovascular & Renal; Cyclic nucleotide phosphodiesterase inhibitors

8-Methoxyquinoline-5-carboxamides as PDE4 inhibitors: a potential treatment for asthma

A series of bicyclic heteroaryl ring systems was considered as a replacement for the 3-cyclopentyloxy-4-methoxyphenyl moiety in rolipram resulting in the discovery of 8-methoxyquinoline-5-carboxamides as potent inhibitors of phosphodiesterase type 4 (PDE4).

7-Methoxyfuro[2,3-c]pyridine-4-carboxamides as PDE4 inhibitors: a potential treatment for asthma

The synthesis and pharmacological profile of a novel series of 7-methoxy-furo[2,3-c]pyridine-4-carboxamides is described. Some of these compounds were found to be potent inhibitors of phosphodiesterase type 4 (PDE4).

Immunopharmacological potential of selective phosphodiesterase inhibition. I. Differential regulation of lipopolysaccharide-mediated proinflammatory cytokine (interleukin-6 and tumor necrosis factor-alpha) biosynthesis in alveolar epithelial cells

In an attempt to elaborate in vitro on a therapeutic strategy that counteracts an inflammatory signal, we previously reported a novel immunopharmacological potential of glutathione, an antioxidant thiol, in regulating inflammatory cytokines. In the present study, we investigated the hypothesis that selective regulation of phosphodiesterases (PDEs), a family of enzymes that controls intracellular cAMP/cGMP degradation, differentially regulates proinflammatory cytokines. Selective PDE1 inhibition (8-methoxymethyl-3-isobutyl-1-methylxanthine) blockaded lipopolysaccharide-endotoxin (LPS)-mediated biosynthesis of interleukin (IL)-6, but this pathway had no inhibitory effect on tumor necrosis factor-alpha (TNF-alpha). Furthermore, inhibition of PDE3 (amrinone) abolished the effect of LPS on IL-6, but attenuated TNF-alpha production. Reversible competitive inhibition of PDE4 (rolipram) exhibited a potent inhibitory effect on IL-6 and a dual, biphasic (excitatory/inhibitory) effect on TNF-alpha secretion. Blockading PDE5 (4-[[3',4'-(methylenedioxy)benzyl] amino]-6-methoxyquinazoline) showed a high potency in reducing IL-6 production, but in a manner similar to the inhibition of PDE4, exhibited a biphasic effect on TNF-alpha biosynthesis. Simultaneous inhibition of PDE5, 6, and 9 (zaprinast), purported to specifically elevate intracellular cGMP, reduced, in a dose-independent manner, IL-6 and TNF-alpha biosynthesis. Finally, nonselective inhibition of PDE by pentoxifylline suppressed LPS-mediated secretion of IL-6 and TNF-alpha. The involvement of specific PDE isoenzymes in differentially regulating LPS-mediated inflammatory cytokine biosynthesis indicates a novel approach to unravel the potential therapeutic targets that these isozymes constitute during the progression of inflammation within the respiratory epithelium.

7-Methoxybenzofuran-4-carboxamides as PDE 4 inhibitors: a potential treatment for asthma

The synthesis and pharmacological profile of a novel series of 7-methoxybenzofuran-4-carboxamides is described. Some of these compounds were found to be potent inhibitors of phosphodiesterase type 4 (PDE4).

PDE4 inhibitors: new xanthine analogues

Novel xanthine analogues are described which are selective PDE4 inhibitors with improved therapeutic potential over theophylline.

Aryl sulfonamides as selective PDE4 inhibitors

A series of novel selective phosphodiesterase 4 (PDE4) inhibitors has been developed which displays activity both in vitro and in vivo. These compounds possess good selectivity for the catalytic site of PDE4 over the high affinity Rolipram binding site. In vivo studies demonstrate a reduced propensity to display the emetic side effects which are commonly observed with PDE4 inhibitors.

Chemotherapeutic potential of phosphodiesterase inhibitors

The application of molecular cloning has revealed the phenomenal diversity and complexity of the phosphodiesterase isoenzyme family. Thus, more than 30 human phosphodiesterases are now known; all are apparently necessary for the seemingly simple task of hydrolysing the 3'-ester bond of either cyclic adenosine monophosphate or cyclic guanosine monophosphate. The availability of phosphodiesterase isoenzymes as pure recombinant proteins has greatly facilitated the identification of potent, selective inhibitors. The potential of these inhibitors to therapeutically exploit the molecular diversity of the phosphodiesterases has progressed significantly. A number of drugs are in clinical trials for asthma, and Viagra has become the first selective phosphodiesterase inhibitor to be approved by the US Food and Drug Administration.