{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,26]],"date-time":"2026-10-26T22:39:27Z","timestamp":1793054367152,"version":"4.5.0"},"reference-count":39,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2026,4,30]],"date-time":"2026-04-30T00:00:00Z","timestamp":1777507200000},"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":["82201685"],"award-info":[{"award-number":["82201685"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["82271553"],"award-info":[{"award-number":["82271553"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"award":["82201685"],"award-info":[{"award-number":["82201685"]}],"id":[{"id":"https:\/\/ror.org\/01h0zpd94","id-type":"ROR","asserted-by":"publisher"}]},{"award":["82271553"],"award-info":[{"award-number":["82271553"]}],"id":[{"id":"https:\/\/ror.org\/01h0zpd94","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Brain Sciences"],"abstract":"<jats:p>Background: Chronic stress is a major risk factor for cognitive decline and blood\u2013brain barrier (BBB) disruption, yet the underlying molecular mechanisms remain elusive. This study aimed to investigate the specific role of the metabolic intermediate homocysteine (Hcy) in chronic stress-induced BBB dysfunction and cognitive impairment. Methods: We utilized a male Sprague-Dawley rat model of chronic unpredictable mild stress (CUMS) and administered vitamin B complex to lower Hcy levels in vivo. Regional Hcy accumulation, BBB permeability, and cognitive behaviors were assessed. In vitro, primary rat brain microvascular endothelial cells (BMECs) were exposed to Hcy to evaluate barrier-forming function, transcriptomic alterations, DNA methylation patterns, Cav1.2 expression, and reactive oxygen species (ROS) production. Results: CUMS selectively induced BBB hyperpermeability and significant Hcy accumulation predominantly within the rat hippocampus, which correlated intimately with cognitive deficits. Lowering Hcy levels via vitamin B supplementation successfully restored hippocampal BBB integrity and alleviated cognitive impairment. In addition, elevated Hcy severely impaired the barrier function of BMECs. Mechanistically, Hcy reduced global DNA methylation in BMECs and specifically induced targeted DNA hypomethylation at the intro region of Cacna1c. This epigenetic shift caused the transcriptional derepression and overexpression of the Cav1.2 calcium channel. Upregulated Cav1.2 subsequently triggered a robust ROS burst, leading to tight junction degradation. Conclusions: Our findings unveil a novel metabolic\u2013epigenetic axis where Hcy-driven Cacna1c hypomethylation directly disrupts BMECs function to dismantle the hippocampal BBB. Lowering Hcy or targeting this Hcy-Cav1.2 pathway establishes a promising therapeutic strategy for mitigating stress-related neurovascular damage and cognitive disorders.<\/jats:p>","DOI":"10.3390\/brainsci16050491","type":"journal-article","created":{"date-parts":[[2026,4,30]],"date-time":"2026-04-30T14:35:53Z","timestamp":1777559753000},"page":"491","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Homocysteine Drives Hippocampal Blood\u2013Brain Barrier Disruption and Cognitive Decline Under Chronic Stress via DNA Hypomethylation of Cav1.2"],"prefix":"10.3390","volume":"16","author":[{"given":"Mao-Yang","family":"Zhou","sequence":"first","affiliation":[{"name":"Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing 100850, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jin-Shan","family":"Li","sequence":"additional","affiliation":[{"name":"Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing 100850, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhao-Xin","family":"Sun","sequence":"additional","affiliation":[{"name":"Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing 100850, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jie","family":"Yin","sequence":"additional","affiliation":[{"name":"Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing 100850, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yun","family":"Zhao","sequence":"additional","affiliation":[{"name":"Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing 100850, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fang","family":"Xie","sequence":"additional","affiliation":[{"name":"Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing 100850, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xue","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing 100850, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sheng-Hui","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing 100850, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhao-Wei","family":"Sun","sequence":"additional","affiliation":[{"name":"Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing 100850, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ling-Jia","family":"Qian","sequence":"additional","affiliation":[{"name":"Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing 100850, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,4,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"100670","DOI":"10.1016\/j.ynstr.2024.100670","article-title":"Effects of chronic stress on cognitive function\u2014From neurobiology to intervention","volume":"33","author":"Girotti","year":"2024","journal-title":"Neurobiol. Stress"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"290","DOI":"10.1038\/nrn3918","article-title":"Stress and the social brain: Behavioural effects and neurobiological mechanisms","volume":"16","author":"Sandi","year":"2015","journal-title":"Nat. Rev. Neurosci."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Mikulska, J., Juszczyk, G., Gawro\u0144ska-Grzywacz, M., and Herbet, M. (2021). HPA axis in the pathomechanism of depression and schizophrenia: New therapeutic strategies based on its participation. Brain Sci., 11.","DOI":"10.3390\/brainsci11101298"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1573","DOI":"10.3233\/JAD-210094","article-title":"Association of stress with risk of dementia and mild cognitive impairment: A systematic review and meta-analysis","volume":"82","author":"Franks","year":"2021","journal-title":"J. Alzheimer\u2019s Dis."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"148","DOI":"10.1016\/j.neubiorev.2017.01.046","article-title":"Psychosocial stress on neuroinflammation and cognitive dysfunctions in alzheimer\u2019s disease: The emerging role for microglia?","volume":"77","author":"Piirainen","year":"2017","journal-title":"Neurosci. Biobehav. Rev."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"311","DOI":"10.1007\/s00401-018-1815-1","article-title":"Functional morphology of the blood-brain barrier in health and disease","volume":"135","author":"Liebner","year":"2018","journal-title":"Acta Neuropathol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"133","DOI":"10.1038\/nrneurol.2017.188","article-title":"Blood-brain barrier breakdown in alzheimer disease and other neurodegenerative disorders","volume":"14","author":"Sweeney","year":"2018","journal-title":"Nat. Rev. Neurol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"887","DOI":"10.1016\/j.bbadis.2015.12.016","article-title":"Neurovascular dysfunction and neurodegeneration in dementia and alzheimer\u2019s disease","volume":"1862","author":"Nelson","year":"2016","journal-title":"Biochim. Biophys. Acta"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1518","DOI":"10.1002\/mds.26698","article-title":"Vascular disease and vascular risk factors in relation to motor features and cognition in early parkinson\u2019s disease","volume":"31","author":"Malek","year":"2016","journal-title":"Mov. Disord."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1186\/s12987-025-00639-8","article-title":"Rutin ameliorates stress-induced blood\u2013brain barrier dysfunction and cognitive decline via the endothelial hdac1\u2013claudin-5 axis","volume":"22","author":"Sun","year":"2025","journal-title":"Fluids Barriers CNS"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"100758","DOI":"10.1016\/j.ynstr.2025.100758","article-title":"High-intensity interval training improves cognitive dysfunction in chronically stressed mice through alleviating homocysteine-induced transcriptional repression of cldn5","volume":"39","author":"Sun","year":"2025","journal-title":"Neurobiol. Stress"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1152","DOI":"10.1016\/j.pnpbp.2005.06.026","article-title":"Homocysteine and brain atrophy","volume":"29","author":"Sachdev","year":"2005","journal-title":"Prog. Neuro-Psychopharmacol. Biol. Psychiatry"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"887","DOI":"10.1007\/s12264-022-00852-7","article-title":"Homocysteine-induced disturbances in DNA methylation contribute to development of stress-associated cognitive decline in rats","volume":"38","author":"Wang","year":"2022","journal-title":"Neurosci. Bull."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Esse, R., Barroso, M., Tavares De Almeida, I., and Castro, R. (2019). The contribution of homocysteine metabolism disruption to endothelial dysfunction: State-of-the-art. Int. J. Mol. Sci., 20.","DOI":"10.3390\/ijms20040867"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"847","DOI":"10.1139\/cjpp-2020-0507","article-title":"Mild hyperhomocysteinemia induces blood-brain barrier dysfunction but not neuroinflammation in the cerebral cortex and hippocampus of wild-type mice","volume":"99","author":"Chu","year":"2021","journal-title":"Can. J. Physiol. Pharmacol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"6852","DOI":"10.1002\/jcp.30382","article-title":"Hydrogen sulfide prevents ethanol-induced zo-1 cpg promoter hypermethylation-dependent vascular permeability via mir-218\/dnmt3a axis","volume":"236","author":"Behera","year":"2021","journal-title":"J. Cell. Physiol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1218","DOI":"10.1016\/j.bbrc.2016.04.042","article-title":"Plasma homocysteine involved in methylation and expression of thrombomodulin in cerebral infarction","volume":"473","author":"Yang","year":"2016","journal-title":"Biochem. Biophys. Res. Commun."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Hu, X., and Zhang, L. (2022). Oxidative regulation of vascular ca(v)1.2 channels triggers vascular dysfunction in hypertension-related disorders. Antioxidants, 11.","DOI":"10.3390\/antiox11122432"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"260","DOI":"10.1016\/j.redox.2015.08.010","article-title":"Calcium and ROS: A mutual interplay","volume":"6","author":"Bertram","year":"2015","journal-title":"Redox Biol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"138","DOI":"10.1016\/j.jpsychires.2024.10.004","article-title":"Breakdown of the blood-brain barrier in depressed mice induced by chronic unpredictable mild stress","volume":"180","author":"Shi","year":"2024","journal-title":"J. Psychiatr. Res."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"113364","DOI":"10.1016\/j.bbr.2021.113364","article-title":"Effect of chronically electric foot shock stress on spatial memory and hippocampal blood brain barrier permeability","volume":"410","author":"Taghadosi","year":"2021","journal-title":"Behav. Brain Res."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"265","DOI":"10.1111\/j.1749-6632.2001.tb05830.x","article-title":"Plasticity of the hippocampus: Adaptation to chronic stress and allostatic load","volume":"933","author":"McEwen","year":"2001","journal-title":"Ann. N. Y. Acad. Sci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"111548","DOI":"10.1016\/j.brainresbull.2025.111548","article-title":"Stress-induced regional characteristics of the blood-brain barrier","volume":"231","author":"Zhou","year":"2025","journal-title":"Brain Res. Bull."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"S\u00e1ntha, P., Veszelka, S., Hoyk, Z., M\u00e9sz\u00e1ros, M., Walter, F.R., T\u00f3th, A.E., Kiss, L., Kincses, A., Ol\u00e1h, Z., and Sepr\u00e9nyi, G. (2015). Restraint stress-induced morphological changes at the blood-brain barrier in adult rats. Front. Mol. Neurosci., 8.","DOI":"10.3389\/fnmol.2015.00088"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1752","DOI":"10.1038\/s41593-017-0010-3","article-title":"Social stress induces neurovascular pathology promoting depression","volume":"20","author":"Menard","year":"2017","journal-title":"Nat. Neurosci."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Pinzon, R.T., Wijaya, V.O., and Veronica, V. (2023). The role of homocysteine levels as a risk factor of ischemic stroke events: A systematic review and meta-analysis. Front. Neurol., 14.","DOI":"10.3389\/fneur.2023.1144584"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"591","DOI":"10.1182\/blood-2005-06-2506","article-title":"Elevated levels of homocysteine compromise blood-brain barrier integrity in mice","volume":"107","author":"Kamath","year":"2006","journal-title":"Blood"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1079","DOI":"10.1021\/acschemneuro.4c00749","article-title":"Oroxylin a attenuates homocysteine-induced blood-brain barrier (BBB) dysfunction by reducing endothelial permeability and activating the CREB\/claudin-5 signaling pathway","volume":"16","author":"Bao","year":"2025","journal-title":"ACS Chem. Neurosci."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1016\/j.neuroscience.2024.11.006","article-title":"Chronic stress disturbed the metabolism of homocysteine in mouse hippocampus and prefrontal cortex","volume":"563","author":"Xue","year":"2024","journal-title":"Neuroscience"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"115483","DOI":"10.1016\/j.intimp.2025.115483","article-title":"Rap1a regulates cums-induced neuroinflammation and cognitive dysfunction and emotional abnormalities in mice","volume":"165","author":"Wei","year":"2025","journal-title":"Int. Immunopharmacol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1186\/s10020-018-0010-0","article-title":"Stachydrine protects eNOS uncoupling and ameliorates endothelial dysfunction induced by homocysteine","volume":"24","author":"Xie","year":"2018","journal-title":"Mol. Med."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"15350","DOI":"10.1074\/jbc.M114.549782","article-title":"Inhibition of cellular methyltransferases promotes endothelial cell activation by suppressing glutathione peroxidase 1 protein expression","volume":"289","author":"Barroso","year":"2014","journal-title":"J. Biol. Chem."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"C609","DOI":"10.1152\/ajpcell.00147.2018","article-title":"Hydrogen sulfide alleviates hyperhomocysteinemia-mediated skeletal muscle atrophy via mitigation of oxidative and endoplasmic reticulum stress injury","volume":"315","author":"Majumder","year":"2018","journal-title":"Am. J. Physiol. Cell Physiol."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Jakubowski, H., and Witucki, \u0141. (2025). Homocysteine metabolites, endothelial dysfunction, and cardiovascular disease. Int. J. Mol. Sci., 26.","DOI":"10.3390\/ijms26020746"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1292","DOI":"10.1373\/49.8.1292","article-title":"Increased homocysteine and s-adenosylhomocysteine concentrations and DNA hypomethylation in vascular disease","volume":"49","author":"Castro","year":"2003","journal-title":"Clin. Chem."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"466","DOI":"10.1093\/cvr\/cvr250","article-title":"Homocysteine promotes human endothelial cell dysfunction via site-specific epigenetic regulation of p66shc","volume":"92","author":"Kim","year":"2011","journal-title":"Cardiovasc. Res."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Lyon, P., Strippoli, V., Fang, B., and Cimmino, L. (2020). B vitamins and one-carbon metabolism: Implications in human health and disease. Nutrients, 12.","DOI":"10.3390\/nu12092867"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1161\/hc0102.101388","article-title":"Folic acid improves endothelial function in coronary artery disease via mechanisms largely independent of homocysteine lowering","volume":"105","author":"Doshi","year":"2002","journal-title":"Circulation"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"132","DOI":"10.3945\/an.113.005207","article-title":"Vitamin b-6","volume":"6","author":"Stover","year":"2015","journal-title":"Adv. Nutr."}],"container-title":["Brain Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-3425\/16\/5\/491\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,14]],"date-time":"2026-05-14T04:21:13Z","timestamp":1778732473000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-3425\/16\/5\/491"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,4,30]]},"references-count":39,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2026,5]]}},"alternative-id":["brainsci16050491"],"URL":"https:\/\/doi.org\/10.3390\/brainsci16050491","relation":{},"ISSN":["2076-3425"],"issn-type":[{"value":"2076-3425","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4,30]]}}}