IL-1b as a potential biomarker and therapeutic target in coronary artery disease

Abstract

Abstract Background Current methods for the early detection of coronary artery disease (CAD) are limited, particularly in those without traditional risk factors. CAD remains a significant cause of morbidity and mortality worldwide, despite advances in diagnostics, treatment and prevention. There is a major unmet need for novel, prognostic blood-based CAD biomarkers, applied to diagnostic strategies or trial endpoints, to accelerate the drug development pipeline and improve clinical trial efficiency. Peripheral blood mononuclear cells (PBMCs) are easily accessible and may serve as a potential cell-derived biomarker or a tool in candidate selection in drug discovery. Purpose This study aims to determine if IL-1β secretion from patient-derived monocytes could differ between patients with calcified atherosclerotic CAD compared with those with no calcified disease and serve as a tool in drug screening. Methods PBMCs were isolated from a cohort of 41 BioHEART participants (ACTRN12618001322224) undergoing clinically indicated CT coronary angiography. We compared 23 participants with CAD, as defined by a coronary artery calcium score (CACS) >0 Agatston units (AU) with 18 participants with no calcified CAD, defined as CACS=0 AU. Monocyte enrichment from PBMCs was achieved through a brief period of in vitro incubation, in which monocytes adhered to the culture plate, while non-monocyte cells were removed by washing. Monocytes were split into 3 conditions; incubated with either (a) 0.01% DMSO in PBS (basal, unstimulated), or (b) stimulated with 1 mM BzATP,or (c) following a 30-minute pre-treatment with a novel P2X7 receptor antagonist, PKT100 (1 μM in PBS 0.01% DMSO), stimulated with BzATP (with PKT100 maintained during the stimulation period). The concentration of IL-1β in supernatant was determined by colormetric ELISA detection. Results We demonstrated that monocytes derived from participants with calcified CAD have a significant elevation in IL-1β secretion following ATP stimulation, when compared to baseline (p<0.0001). While baseline concentration of IL-1β did not differ between control and CAD groups, ATP stimulation of monocytes resulted in a 3.40-fold higher IL-1β concentration in the CAD group compared with the control group (p<0.0001). ATP stimulation of the CAD group in the presence of PKT100 markedly reduced the monocyte IL-1β secretion to near baseline concentrations (p<0.0001). Conclusions Here, we have shown for the first time that PBMCs isolated from participants with CAD secrete higher concentrations of IL-1β upon ATP stimulation compared with non-CAD individuals. This response was markedly reduced after treatment with PKT100, confirming a role for the P2X7 receptor in modulating the downstream IL-1β response to ATP signalling. Further studies are required to understand whether a P2X7 receptor antagonist could be a potential treatment of inflammation associated with CAD.ATP stimulation of CAD patient monocytes