Acetylcholine Reduces Monomeric C-Reactive Protein Pro-Inflammatory Activity

Iemma, R. S. (2021) Acetylcholine Reduces Monomeric C-Reactive Protein Pro-Inflammatory Activity. Doctoral thesis (PhD), Manchester Metropolitan University.

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Abstract

INTRODUCTION: inflammation increases the production of pro-inflammatory cytokines, that, on binding to their respective receptors in the liver, stimulate the synthesis of native CRP (nCRP). nCRP can be dissociated into sub-units or monomeric CRPs (mCRPs) and can be locally accumulated with macrophages in the same chronic inflamed tissue. Therefore, the goal of the present project was to investigate the potential of mCRP pro-inflammatory activity and the potential of new effective small molecule inhibitors (SMIs) in blocking mCRP effects. MATERIALS AND METHODS: differentiated human U937 macrophage-like cells were stimulated by mCRP in the presence or absence of small molecular compounds, such as Acetylcholine (ACh) and Nicotine or the 3H12 antibody. The levels of tumour necrosis factor-α (TNF-α), Interleukin-6 (IL-6); and IL-10 were determined by enzyme-linked immunosorbent (ELISA) assay. Western Blotting was used to evaluate the intrinsic pro-inflammatory pathway. The RT-PCR was used to determine mCRP RNA gene expression. RESULTS: mCRP increased TNF-α and IL-6 concentrations. ACh significantly inhibited the mCRP induced TNF-α and IL-6 release. Western blotting confirmed that ACh blocks mCRP-induced cell signalling phosphorylation of ERK, JNK, and NF-KB. The RT-PCR results showed that mCRP increases cytokine RNA expression, whereas ACh was unable to reduce it. CONCLUSIONS: this study demonstrated that mCRP had a robust pro-inflammatory activity, whilst the use of ACh inhibited its proinflammatory activity, therefore reducing TNF-α, IL-6 and IL-10 release. Indeed, it is likely that the monomeric CRP could be a promising new target for the prevention and treatment of chronic inflammation tissue associated with chronic kidney diseases, arteriosclerosis and stroke.