ObjectiveThe current study aimed to investigate the role of the myocardial infarction-associated transcript (MIAT)/microRNA-326 (miR-326) axis in regulating the migration of vascular smooth muscle cells (VSMCs) during the progression of atherosclerosis (AS).MethodsBioinformatic analysis of MIAT and miR-326 in two AS-related GEO datasets was performed via the online web tool GEO2R. MIAT and miR-326 expression in 46 paired plasma samples and in oxidized low-density lipoprotein (ox-LDL)-treated VSMCs was analysed via RT-qPCR. Western blot analysis was used to determine the expression of monocyte chemotactic protein 1 (MCP-1) after diverse ox-LDL treatments. The correlation between MIAT and miR-326 was analysed by Spearman correlation analysis. Transwell assays were performed to determine the changes in migration after different MIAT or miR-326 interventions. RNA-fluorescence in situ hybridization (FISH) assays were performed to determine the subcellular localization of MIAT and miR-326. The targeted binding effect between MIAT and miR-326 was confirmed via a luciferase assay.ResultsMIAT was upregulated and miR-326 was downregulated in 46 plasma samples from patients with AS compared with those from patients without AS (non-AS). A negative correlation was found between MIAT and miR-326 (r = - 0.6591,  < 0.0001). The expression of MIAT in plaque samples from advanced AS patients was markedly greater than that in plaque samples from early AS patients according to the GEO dataset GSE28829 ( < 0.0001). The expression of miR-326 in platelet samples from patients with first acute myocardial infarction (FAMI) was significantly lower than that in healthy controls ( = 0.0034). MCP-1 was upregulated in ox-LDL-treated VSMCs. MIAT knockdown by specific MIAT small interfering RNAs (siRNAs) suppressed VSMC migration. Upregulation of miR-326 by transfection of miR-326 mimics also inhibited VSMC migration. Dual luciferase assays indicated that miR-326 targets MIAT. The upregulation of MIAT increased the migration of VSMCs. However, this effect was attenuated by a miR-326 mimic.ConclusionsMIAT was upregulated and miR-326 was downregulated in AS plasma and in ox-LDL-treated VSMCs. MIAT binds to miR-326 via theoretical miRNA response elements. MIAT promoted migration by sponging miR-326 in ox-LDL-induced VMSCs. The MIAT/miR-326 axis may represent a novel therapeutic target for the treatment of AS, offering potential insights into AS progression and its clinical management.