{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,12]],"date-time":"2026-02-12T06:14:59Z","timestamp":1770876899792,"version":"3.50.1"},"reference-count":25,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,2,5]],"date-time":"2026-02-05T00:00:00Z","timestamp":1770249600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["82560066"],"award-info":[{"award-number":["82560066"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Major Project of the Science and Technology Department of Jiangxi","award":["20223BBG71010"],"award-info":[{"award-number":["20223BBG71010"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCDD"],"abstract":"<jats:p>Atrial fibrillation (AF) is closely linked to atrial remodeling, while its underlying immune mechanisms remain elusive. This study sought to investigate the role of SPP1+ macrophages in the development and progression of AF and further elucidate the underlying mechanisms. Single-nucleus RNA sequencing was performed on right atrial tissues from 3 patients with persistent AF and 3 with sinus rhythm (all with rheumatic valvular heart disease). The results revealed significant immune cell infiltration in AF atrial tissues, with a marked increase in the proportion of SPP1+ macrophages, which exhibited the strongest intercellular communication with cardiomyocytes. Phenotypic scoring indicated that apoptosis was the dominant mode of cardiomyocyte death in AF. Immunohistochemical and Western blot analyses confirmed elevated levels of pro-apoptotic proteins (Bax, Cleaved-Caspase3) and reduced levels of the anti-apoptotic protein Bcl2 in AF tissues. In a mouse model with macrophage-specific SPP1 overexpression, increased AF inducibility and duration were observed, accompanied by enhanced cardiomyocyte apoptosis. In vitro co-culture experiments using SPP1-overexpressing RAW264.7 macrophages and HL-1 cardiomyocytes confirmed that SPP1+ macrophages could induce cardiomyocyte apoptosis. Mechanistically, KEGG and GSEA analyses identified downregulation of the PI3K\/AKT pathway in AF. Treatment with the PI3K\/AKT activator Recilisib reversed apoptosis and restored p-PI3K\/p-AKT levels in HL-1 cells co-cultured with SPP1-overexpressing RAW264.7 macrophages. These findings demonstrate that SPP1+ macrophages accumulate in atrial tissues of AF patients and induce cardiomyocyte apoptosis by downregulating the PI3K\/AKT pathway, thereby increasing AF susceptibility.<\/jats:p>","DOI":"10.3390\/jcdd13020080","type":"journal-article","created":{"date-parts":[[2026,2,5]],"date-time":"2026-02-05T16:30:47Z","timestamp":1770309047000},"page":"80","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Single-Nucleus RNA Sequencing Reveals SPP1+ Macrophages Induce Cardiomyocyte Apoptosis to Promote Atrial Fibrillation Susceptibility"],"prefix":"10.3390","volume":"13","author":[{"given":"Weixue","family":"Wang","sequence":"first","affiliation":[{"name":"Department of Cardiovascular Medicine, The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Minde Road No. 1, Nanchang 330006, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Youzheng","family":"Dong","sequence":"additional","affiliation":[{"name":"Department of Cardiovascular Medicine, The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Minde Road No. 1, Nanchang 330006, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hong","family":"Yi","sequence":"additional","affiliation":[{"name":"Department of Cardiovascular Medicine, The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Minde Road No. 1, Nanchang 330006, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lei","family":"He","sequence":"additional","affiliation":[{"name":"Department of Cardiovascular Medicine, The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Minde Road No. 1, Nanchang 330006, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuwen","family":"Jiang","sequence":"additional","affiliation":[{"name":"Department of Cardiovascular Medicine, The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Minde Road No. 1, Nanchang 330006, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lu","family":"Long","sequence":"additional","affiliation":[{"name":"Department of Cardiovascular Medicine, The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Minde Road No. 1, Nanchang 330006, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zhen","family":"Xia","sequence":"additional","affiliation":[{"name":"Department of Cardiovascular Medicine, The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Minde Road No. 1, Nanchang 330006, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Juxiang","family":"Li","sequence":"additional","affiliation":[{"name":"Department of Cardiovascular Medicine, The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Minde Road No. 1, Nanchang 330006, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1038\/s41572-022-00347-9","article-title":"Atrial fibrillation","volume":"8","author":"Brundel","year":"2022","journal-title":"Nat. Rev. Dis. Primers"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"e93","DOI":"10.1161\/CIR.0000000000001123","article-title":"Heart Disease and Stroke Statistics-2023 Update: A Report from the American Heart Association","volume":"147","author":"Tsao","year":"2023","journal-title":"Circulation"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"e56","DOI":"10.1161\/CIR.0000000000000659","article-title":"Heart Disease and Stroke Statistics-2019 Update: A Report from the American Heart Association","volume":"139","author":"Benjamin","year":"2019","journal-title":"Circulation"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"3314","DOI":"10.1093\/eurheartj\/ehae176","article-title":"2024 ESC Guidelines for the management of atrial fibrillation developed in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS)","volume":"45","author":"Rienstra","year":"2024","journal-title":"Eur. Heart J."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"292","DOI":"10.1016\/j.ahj.2012.05.017","article-title":"A proposal for new clinical concepts in the management of atrial fibrillation","volume":"164","author":"Camm","year":"2012","journal-title":"Am. Heart J."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1027","DOI":"10.1161\/CIRCULATIONAHA.117.031431","article-title":"Genetic Predisposition, Clinical Risk Factor Burden, and Lifetime Risk of Atrial Fibrillation","volume":"137","author":"Weng","year":"2018","journal-title":"Circulation"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"389","DOI":"10.1016\/j.jacc.2020.06.004","article-title":"Important Differences Exist Between Atrial Fibrillation and Atrial Flutter in Atrial Remodeling","volume":"76","author":"Calkins","year":"2020","journal-title":"J. Am. Coll. Cardiol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"145","DOI":"10.1038\/s41569-022-00759-w","article-title":"Inflammatory signalling in atrial cardiomyocytes: A novel unifying principle in atrial fibrillation pathophysiology","volume":"20","author":"Dobrev","year":"2023","journal-title":"Nat. Rev. Cardiol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1016\/j.jare.2023.09.012","article-title":"Deciphering mechanisms of cardiomyocytes and non-cardiomyocyte transformation in myocardial remodeling of permanent atrial fibrillation","volume":"61","author":"Sheng","year":"2024","journal-title":"J. Adv. Res."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1163","DOI":"10.1016\/j.jacc.2023.12.034","article-title":"Genetic Factors Altering Immune Responses in Atrial Fibrillation: JACC Review Topic of the Week","volume":"83","author":"Ninni","year":"2024","journal-title":"J. Am. Coll. Cardiol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"2072","DOI":"10.1016\/j.immuni.2021.07.003","article-title":"Resident cardiac macrophages mediate adaptive myocardial remodeling","volume":"54","author":"Wong","year":"2021","journal-title":"Immunity"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"198","DOI":"10.1016\/j.yjmcc.2018.09.007","article-title":"The role of immune cells in atrial fibrillation","volume":"123","author":"Liu","year":"2018","journal-title":"J. Mol. Cell Cardiol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1007\/s00395-016-0584-z","article-title":"Cross-talk between macrophages and atrial myocytes in atrial fibrillation","volume":"111","author":"Sun","year":"2016","journal-title":"Basic Res. Cardiol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"231","DOI":"10.1126\/science.abq3061","article-title":"Recruited macrophages elicit atrial fibrillation","volume":"381","author":"Hulsmans","year":"2023","journal-title":"Science"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Chen, Y., Ouyang, T., Yin, Y., Fang, C., Tang, C.E., Luo, J., and Luo, F. (2022). Analysis of infiltrated immune cells in left atriums from patients with atrial fibrillation and identification of circRNA biomarkers for postoperative atrial fibrillation. Front. Genet., 13.","DOI":"10.3389\/fgene.2022.1003366"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Smorodinova, N., Blaha, M., Melenovsky, V., Rozsivalova, K., Pridal, J., Durisova, M., Pirk, J., Kautzner, J., and Kucera, T. (2017). Analysis of immune cell populations in atrial myocardium of patients with atrial fibrillation or sinus rhythm. PLoS ONE, 12.","DOI":"10.1371\/journal.pone.0172691"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Zhao, Y., Huang, Z., Gao, L., Ma, H., and Chang, R. (2024). Osteopontin\/SPP1: A potential mediator between immune cells and vascular calcification. Front. Immunol., 15.","DOI":"10.3389\/fimmu.2024.1395596"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"384","DOI":"10.1016\/j.molmet.2014.03.004","article-title":"Osteopontin: A novel regulator at the cross roads of inflammation, obesity and diabetes","volume":"3","author":"Kahles","year":"2014","journal-title":"Mol. Metab."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"279","DOI":"10.1038\/s41392-023-01497-2","article-title":"Interaction between neutrophil extracellular traps and cardiomyocytes contributes to atrial fibrillation progression","volume":"8","author":"He","year":"2023","journal-title":"Signal Transduct. Target. Ther."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Huang, M., Huiskes, F.G., de Groot, N.M.S., and Brundel, B. (2024). The Role of Immune Cells Driving Electropathology and Atrial Fibrillation. Cells, 13.","DOI":"10.3390\/cells13040311"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"111458","DOI":"10.1016\/j.cellsig.2024.111458","article-title":"Inhibition of TREM-1 ameliorates angiotensin II-induced atrial fibrillation by attenuating macrophage infiltration and inflammation through the PI3K\/AKT\/FoxO3a signaling pathway","volume":"124","author":"Chen","year":"2024","journal-title":"Cell. Signal."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"382","DOI":"10.1093\/cvr\/cvaf017","article-title":"Immune cells and arrhythmias","volume":"121","author":"Keefe","year":"2025","journal-title":"Cardiovasc. Res."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"280","DOI":"10.1186\/s13287-024-03814-0","article-title":"Immune response caused by M1 macrophages elicits atrial fibrillation-like phenotypes in coculture model with isogenic hiPSC-derived cardiomyocytes","volume":"15","author":"Hutschalik","year":"2024","journal-title":"Stem Cell Res. Ther."},{"key":"ref_24","first-page":"648","article-title":"Novel macrophage targets for the treatment of atrial fibrillation","volume":"20","author":"Huynh","year":"2023","journal-title":"Nat. Rev. Cardiol."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Yao, Y., Yang, M., Liu, D., and Zhao, Q. (2022). Immune remodeling and atrial fibrillation. Front. Physiol., 13.","DOI":"10.3389\/fphys.2022.927221"}],"container-title":["Journal of Cardiovascular Development and Disease"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2308-3425\/13\/2\/80\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,2,12]],"date-time":"2026-02-12T05:20:53Z","timestamp":1770873653000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2308-3425\/13\/2\/80"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,2,5]]},"references-count":25,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2026,2]]}},"alternative-id":["jcdd13020080"],"URL":"https:\/\/doi.org\/10.3390\/jcdd13020080","relation":{},"ISSN":["2308-3425"],"issn-type":[{"value":"2308-3425","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,2,5]]}}}