Ms4a6d in macrophages accelerated the progression of AAA via modulating SYK/PI3K/CREB/STING signaling induced inflammation and MMPs expression

To investigate the role of Ms4a6d in the formation of abdominal aortic aneurysm (AAA) in mice and explore its underlying mechanism. Bioinformatic approaches were applied to comprehensively analyze transcriptomic and single-cell sequencing data obtained from AAA lesions and normal abdominal aortic tissues in mice. In vivo, 36 male ApoE⁻/⁻ mice were randomly divided into Sham, Model, Model+Ms4a6d-OE, and Model+Ms4a6d-KD groups ( n = 9/group). Aneurysm size was assessed by Masson staining, and macrophage infiltration by F4/80 immunohistochemistry. Dual immunofluorescence staining was performed to detect whether Ms4a6d is specifically expressed in macrophages. In vitro, RAW264.7 macrophages were transduced with Ms4a6d-OE or Ms4a6d-KD lentivirus and stimulated with Ang Ⅱ under hypoxia. A sequential pharmacological intervention strategy was employed using Piceatannol (SYK inhibitor), Activator 1 (PI3K/Akt/CREB activator), 666 − 15 (CREB inhibitor), and SR-717 (STING agonist). Protein expression was detected by Western blot; secretion of IL-1β, IL-18, MMP-2, and MMP-9 was measured by ELISA; MMP-2/9 enzymatic activities were assessed by gelatin zymography; and cell invasion was evaluated by Transwell assay. Co-immunoprecipitation was used to assess CREB-STING interaction. Bulk RNA‑seq analysis revealed widespread upregulation of genes related to immune inflammation and matrix remodeling in AAA at the tissue level, and further demonstrated a co‑expression network involving Ms4a6d, SYK, PI3K, CREB, STING, and MMPs. Single-cell transcriptomic analysis further revealed that the above alterations predominantly occurred within macrophage subpopulations, indicating that macrophages in AAA underwent metabolic reprogramming, exhibited enhanced differentiation potential and dysfunction, and showed shifted pseudotime differentiation trajectories. These findings also suggest that Ms4a6d may participate in these processes by regulating CREB. In vivo, Ms4a6d is predominantly expressed in macrophages. Ms4a6d overexpression increased AAA diameter and macrophage infiltration, while Ms4a6d knockdown reduced both. In vitro, Ms4a6d overexpression upregulated p-SYK, p-PI3K, p-CREB, p-STING, NLRP3, IL-1β, MMP-2, and MMP-9, enhanced IL-1β, IL-18, MMP-2, and MMP-9 secretion, increased MMP-2/9 gelatinolytic activities, and promoted macrophage invasion. Piceatannol blocked these effects, which were sequentially rescued by activator 1, suppressed by 666 − 15, and again enhanced by SR-717, confirming the hierarchical Ms4a6d/SYK/PI3K/CREB/STING axis. Co-IP demonstrated direct CREB-STING interaction. Ms4a6d in macrophages accelerates AAA progression by regulating the SYK/PI3K/CREB/STING signaling pathway, inducing inflammation and MMP expression.