Acetylcholine Inhibits Monomeric C-Reactive Protein Induced Inflammation, Endothelial Cell Adhesion, and Platelet Aggregation; A Potential Therapeutic?

Abstract

Objectives: In this study, we examined the possibility of using targeted antibodies and the potential of small molecular therapeutics (acetylcholine, nicotine and tacrine) to block the pro-inflammatory and adhesion-related properties of monomeric C-reactive protein (mCRP).Methods: We used three established models (platelet aggregation assay, endothelial leucocyte binding assay and monocyte inflammation via ELISA and Western blotting) to assess the potential of these therapeutics.Results: The results of this study showed that monocyte induced inflammation (raised tumor necrosis factor-alpha-TNF-α) induced by mCRP was significantly blocked in the presence of acetylcholine and nicotine, whilst tacrine and targeted antibodies (clones 8C10 and 3H12) had less of or no significant effects. Western blotting confirmed the ability of acetylcholine to inhibit mCRP-induced cell signaling phosphorylation of extracellular signal regulated kinase 1/2 (ERK1/2), p38 and nuclear factor-kappa B (NF-κB). There was no evidence of direct binding between small molecules and mCRP. mCRP also induced endothelial cell-monocyte adhesion in a dose dependent fashion, however, both acetylcholine and nicotine as well as targeting antibodies notably inhibited adhesion. Finally, we investigated their effects on mCRP-induced platelet aggregation. All three small molecules significantly attenuated platelet aggregation as did the antibody 8C10, although 3H12 had a weaker effect.Discussion: Acetylcholine and to a lesser extent nicotine show potential for therapeutic inhibition of mCRP-induced inflammation and cell and platelet adhesion. These results highlight the potential of targeted antibodies and small molecule therapeutics to inhibit the binding of mCRP by prevention of membrane interaction and subsequent activation of cellular cascade systems, which produce the pro-inflammatory effects associated with mCRP.

Editorial: C-Reactive Protein in Age-Related Disorders

“…CRP is known to affect innate immunity operating through the nicotinic acetylcholine receptors and here, Richter et al ( 9 ) showed that pCRP associated with phosphocholine, could block macrophage-induced cytokine release potentially protecting trauma-associated injuries in vivo . In contrast, mCRP potently stimulates macrophage-associated inflammation, and further work detailed in this series showed that acetylcholine inclusion, within an in vitro model of inflammation, could effectively block mCRP-induced production of tumor necrosis factor-alpha ( 10 ).…”

The Multiple Faces of C-Reactive Protein—Physiological and Pathophysiological Implications in Cardiovascular Disease

“…The above findings have been later supported by experimental studies indicating that 1,6-bis-PC is able to prevent the dissociation of CRP and inhibit its deposition in inflamed tissue [101]. Very recently, acetylcholine and nicotine have been found to have beneficial effects on reducing mCRP-induced inflammatory events [102]. Taken together, these findings encourage further testing: more pharmacokinetic and pharmacodynamic data acquired by local and systemic approaches are required to determine whether these substances are suitable for clinical purposes.…”

Monomeric C-Reactive Protein Localized in the Cerebral Tissue of Damaged Vascular Brain Regions Is Associated With Neuro-Inflammation and Neurodegeneration-An Immunohistochemical Study

“…Monomeric C-reactive protein was recently shown to directly exert a pro-inflammatory effect upon macrophages and glia, via induction of nitric oxide synthase ( 21 ) and TNF-α/IL-1β amongst other cytokines ( 22 ). Hence this could be a mechanism that could partially explain how the deposition of mCRP may support creation of a pro-inflammatory micro-environment perpetuating on going damage.…”

“…In regard to the possible relationship to angiogenesis, aberrant angiogenesis associated with formation of none-patent or leaky microvessels as part of a regenerative or restorative effort within damaged brain tissue only serves to permeabilise the parenchyma thereby further increasing immune cell infiltration and so on and so forth ( 2 , 22 ). It was recently shown that mCRP was able to disrupt the outer retinal blood brain barrier indicating a potential role in inflammatory macular degeneration ( 23 ), taken together, it appears that mCRP may have distinct effects both directly upon the vascular integrity and other pro-inflammatory stimulatory effects that combined could impact upon the normal function of the neurovascular unit.…”