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Despite reports on the efficacy of proprotein convertase subtilisin-Kexin type 9 (PCSK9) inhibitors as a potent lipid-lowering agent in various large-scale clinical trials, the anti-atherogenic properties of PCSK9 inhibitors in reducing PCSK9 and atherogenesis biomarkers via the NF-ĸB and eNOS pathway has yet to be established. This study aimed to investigate the effects of PCSK9 inhibitors on PCSK9, targeted early atherogenesis biomarkers, and monocyte binding in stimulated human coronary artery endothelial cells (HCAEC). HCAEC were stimulated with lipopolysaccharides (LPS) and incubated with evolocumab and alirocumab. The protein and gene expression of PCSK9, interleukin-6 (IL-6), E-selectin, intercellular adhesion molecule 1 (ICAM-1), nuclear factor kappa B (NF-ĸB) p65, and endothelial nitric oxide synthase (eNOS) were measured using ELISA and QuantiGene plex, respectively. The binding of U937 monocytes to endothelial cell capacity was measured by the Rose Bengal method. The anti-atherogenic effects of evolocumab and alirocumab were contributed to by the downregulation of PCSK9, early atherogenesis biomarkers, and the significant inhibition of monocyte adhesion to the endothelial cells via the NF-ĸB and eNOS pathways. These suggest the beyond cholesterol-lowering beneficial effects of PCSK9 inhibitors in impeding atherogenesis during the initial phase of atherosclerotic plaque development, hence their potential role in preventing atherosclerosis-related complications.

Low mineralization activity by human osteoblast cells (HOBs) indicates abnormal bone remodeling that potentially leads to osteoporosis. Oxidation, the most prominent form of high-density lipoprotein (HDL) modification, is suggested to affect bone mineralization through the inflammatory pathway. Adiponectin, which possesses anti-inflammatory activity, is postulated to have the ability to suppress the detrimental effects of oxidized HDL (oxHDL). This study aimed to investigate the effects of HDL before and after oxidation on markers of mineralization and inflammation. The protective effects of adiponectin on demineralization and inflammation induced by oxHDL were also investigated. OxHDL at 100 µg/mL protein had the highest inhibitory effect on mineralization, followed by lower calcium incorporation. OxHDL also had significantly lower expression of a mineralization marker (COL1A2) and higher expression of inflammatory markers (IL-6, TNF-α, and RELA proto-oncogene, NF-κβ (p65)) compared to the unstimulated control group. These findings suggest that oxHDL reduces the mineralization activity of HOBs by increasing the expression of inflammatory markers. Interestingly, co-incubation of adiponectin and oxHDL in HOBs resulted in higher expression of mineralization markers (ALPL, COL1A2, BGLAP, and RUNX2) and significantly reduced all targeted inflammatory markers compared to the oxHDL groups. On the contrary, HDL increased the expression of mineralization markers (COL1A2 and STAT-3) and exhibited lower expression of inflammatory cytokines (IL-6 and TNF-α), proving the protective effect of HDL beyond the reverse cholesterol transport activity.