3′‐Sialyllactose Prevents Atherosclerosis by Attenuating Chronic Inflammation via the Gut‐Immune‐Cardiovascular Axis in LDLR ^−/− Mice

ABSTRACT

3′‐sialyllactose (3′‐SL) has demonstrated potential in regulating glycolipid metabolism and improving intestinal immunity, thereby exhibiting anti‐atherosclerotic (AS) properties. However, the mechanism by which 3′‐SL exerts its anti‐AS effects through the regulation of inflammatory signaling via intestinal immunity remains unknown. Herein, 40 male low‐density lipoprotein receptor knockout ( LDLR ^−/− ) mice were randomized into five groups: normal diet (ND), high‐cholesterol diet (HCD), and three 3′‐SL groups (low dose SLL, medium dose SLM, high dose SLH). After 12 weeks, atherosclerotic plaque formation, serum lipids including total cholesterol (TC), triglycerides (TG), low‐density lipoprotein (LDL), high‐density lipoprotein (HDL), and inflammatory cytokines including interleukin‐6 (IL‐6), interleukin‐1β (IL‐1β), interleukin‐10 (IL‐10) were measured. Multi‐omics analyses (gut microbiota 16S sequencing, colonic transcriptomics, and metabolomics) were performed. Compared with the HCD group, 3′‐SL L intervention dose‐dependently and significantly reduced aortic lipid deposition in LDLR ^−/− mice, lowered serum TG and LDL levels, increased HDL, while markedly decreasing pro‐inflammatory cytokines IL‐6 and IL‐1β and elevating the anti‐inflammatory cytokine IL‐10. Using the SLM group as representative for mechanistic exploration, it was found that 3′‐SL reshaped the gut microbiota structure, significantly increasing the abundance of beneficial Akkermansia and reducing the Firmicutes/Bacteroidetes ratio, thereby restoring microbial balance. Integrated multi‐omics analysis further revealed that 3′‐SL drove colonic transcriptomic‐metabolic reprogramming, with enriched key pathways mainly involving immune regulation (e.g., Ccl2, Il2ra ) and lipid metabolism (e.g., Kng1, C6 ). Differential metabolites showed significant correlations with immune‐ and cardiovascular‐related genes. Among these, Ccl2 (MCP‐1), as a key molecule linking gut immune signals to coronary artery pathology, was suppressed in expression, which may directly reduce the recruitment of monocytes/macrophages into the subendothelial space, thereby inhibiting the initiation of atherosclerosis. Collectively, 3′‐SL exhibits significant preventive effects against chronic inflammation in LDLR ^−/− mice with HCD‐induced atherosclerosis. These effects are mediated through synergistic regulation of metabolic, inflammatory, and microbial pathways along the gut microbiota‐immune‐cardiovascular axis. This axis integrates gut microbial metabolism, immune responses, and transcriptional signaling changes, revealing novel targets for the prebiotic 3′‐SL in preventing atherosclerosis. It provides robust preclinical evidence for nutritional intervention strategies targeting the gut microbiota.