Identification of Chlamydia pneumoniae and NLRP3 inflammasome activation in Alzheimer’s disease retina

Identification of Chlamydia pneumoniae and NLRP3 inflammasome activation in Alzheimer’s disease retina | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Identification of Chlamydia pneumoniae and NLRP3 inflammasome activation in Alzheimer’s disease retina Maya Koronyo-Hamaoui, Bhakta Prasad Gaire, Yosef Koronyo, Jean-Philippe Vit, and 16 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6658954/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 22 Jan, 2026 Read the published version in Nature Communications → Version 1 posted You are reading this latest preprint version Abstract Emerging evidence implicates bacterial infections, including Chlamydia pneumoniae (Cp), a gram-negative obligate intracellular bacterium responsible for community-acquired pneumonia, in Alzheimer’s disease (AD) pathogenesis. However, the involvement of Cp in early and advanced AD in the retina is unknown. Here, we identified the existence and distribution of intracellular Cp inclusions and related NLRP3 inflammasome activation and neurodegeneration in postmortem retinas and brains from 95 human donors. Histological analysis in neuropathologically-confirmed MCI and AD patients compared with cognitively normal individuals (n=70), revealed 2.9-4.1-fold increases of Cp inclusions in AD retinas and brains, respectively, with no significant increases in MCI retinas or brains. Mass spectrometry-based proteomics in additional cohorts (n=30), revealed dysregulated brain and retinal bacterial infection-related proteins and inflammasome-associated pathways. Retinal Cp was strongly linked to Aβ 42 , caspase-1 and NLRP3-inflammasome activation components, as well as cleaved caspase-3 + apoptosis and cleaved gasdermin D pyroptotic cell death. Despite increased IBA1 + microgliosis in the AD retina, the Cp-associated microglial population was reduced by 62%, suggesting impaired microglial phagocytosis. Higher retinal Cp burden correlated with APOEε4 status, advanced Braak stage, and cognitive decline. Machine learning models revealed that retinal Cp or NLRP3, in combination with retinal Aβ 42 , effectively predicted AD diagnosis, Braak stage, and cognition. These findings suggest that Cp infection contributes to AD dementia but is unlikely to initiate AD pathological changes, whereas elevated retinal NLRP3 may serve as an early AD marker. These results underscore the need for future studies investigating Cp's role in AD dementia and testing early antibiotic or inflammasome-targeting therapies. Biological sciences/Neuroscience/Diseases of the nervous system/Alzheimer's disease Biological sciences/Neuroscience/Neuroimmunology Alzheimer’s disease Chlamydia pneumoniae (Cp) retina gliosis NLRP3 inflammasome apoptosis machine learning Full Text Additional Declarations There is NO Competing Interest. Supplementary Files GaireKoronyoetal.SupplementaryTablesandfigures5.13.25.pdf Identification of Chlamydia pneumoniae and NLRP3 inflammasome activation in Alzheimer’s disease retina Cite Share Download PDF Status: Published Journal Publication published 22 Jan, 2026 Read the published version in Nature Communications → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6658954","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":470753058,"identity":"a38766ae-afac-4ea1-9d5f-85fd03e038f5","order_by":0,"name":"Maya Koronyo-Hamaoui","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA90lEQVRIiWNgGAWjYBACgwNAgrENyvvAwJBAUIslWEsPhMM4gxgt9gegSkGAmYcYLWbHzxh+YNxgk88v3WP42KamLk++gfnYxy/4tJzJMZZgfJBmOXPOGWPjnGOHiw0OsCXPlsGn5UCOAVDLYQODGzlm0rkNBxI3MPAYM0vg0WJw/o3xD8YNUC2WDXWJ8xsIaQGqlGCcAdXC2MCc2HCAx5jxA14tz8osEnvSDCRnpBUb9hw7nLjhMFsyMx4dQIclb77xsc3GgF8ieeODHzVAh7U3H2b8gU8PA4cBNC6ADDBghkQQHsD+AJ0BjFv8toyCUTAKRsEIAwCHfFE1b/ePWAAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0000-0003-2864-8442","institution":"Cedars-Sinai Medical Center","correspondingAuthor":true,"prefix":"","firstName":"Maya","middleName":"","lastName":"Koronyo-Hamaoui","suffix":""},{"id":470753059,"identity":"11ba1717-23ee-4c6c-98df-f4b8e7087354","order_by":1,"name":"Bhakta Prasad Gaire","email":"","orcid":"","institution":"Cedars-Sinai Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Bhakta","middleName":"Prasad","lastName":"Gaire","suffix":""},{"id":470753060,"identity":"d58305ad-9cdb-4bd9-9aab-0fba0b54cd96","order_by":2,"name":"Yosef Koronyo","email":"","orcid":"","institution":"Cedars-Sinai Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Yosef","middleName":"","lastName":"Koronyo","suffix":""},{"id":470753061,"identity":"48abd72b-61d2-46d9-8900-852ebf527ba5","order_by":3,"name":"Jean-Philippe Vit","email":"","orcid":"","institution":"Cedars-Sinai Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Jean-Philippe","middleName":"","lastName":"Vit","suffix":""},{"id":470753062,"identity":"a4c33e5a-40a5-48cc-8df1-dced07eec5f4","order_by":4,"name":"Alexandre Hutton","email":"","orcid":"","institution":"Cedars-Sinai Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Alexandre","middleName":"","lastName":"Hutton","suffix":""},{"id":470753063,"identity":"cf2a40e7-dcad-4ed7-907c-81d87568aeb4","order_by":5,"name":"Natalie Swerdlow","email":"","orcid":"","institution":"Cedars-Sinai Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Natalie","middleName":"","lastName":"Swerdlow","suffix":""},{"id":470753064,"identity":"12f93810-1ff7-464a-b6d5-d10ad966364a","order_by":6,"name":"Edward Robinson","email":"","orcid":"","institution":"Cedars-Sinai Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Edward","middleName":"","lastName":"Robinson","suffix":""},{"id":470753065,"identity":"0c373bec-21ff-446d-b230-8c855fbd20e3","order_by":7,"name":"Dieu-Trang Fuchs","email":"","orcid":"","institution":"Cedars-Sinai Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Dieu-Trang","middleName":"","lastName":"Fuchs","suffix":""},{"id":470753066,"identity":"34c60951-857e-43ee-8816-cb2de9534182","order_by":8,"name":"Altan Rentsendorj","email":"","orcid":"","institution":"Cedars-Sinai Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Altan","middleName":"","lastName":"Rentsendorj","suffix":""},{"id":470753067,"identity":"355aa137-c853-486c-b242-9ca069c1e6c1","order_by":9,"name":"Lalita Subedi","email":"","orcid":"","institution":"Cedars-Sinai Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Lalita","middleName":"","lastName":"Subedi","suffix":""},{"id":470753068,"identity":"0598865f-1553-406a-b504-8a0284a01928","order_by":10,"name":"Alexander Ljubimov","email":"","orcid":"https://orcid.org/0000-0003-2398-5319","institution":"Cedars-Sinai Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Alexander","middleName":"","lastName":"Ljubimov","suffix":""},{"id":470753069,"identity":"3224a01e-158b-45d6-9783-cb512c83165d","order_by":11,"name":"Lon S. 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However, the involvement of Cp in early and advanced AD in the retina is unknown. Here, we identified the existence and distribution of intracellular Cp inclusions and related NLRP3 inflammasome activation and neurodegeneration in postmortem retinas and brains from 95 human donors. Histological analysis in neuropathologically-confirmed MCI and AD patients compared with cognitively normal individuals (n=70), revealed 2.9-4.1-fold increases of Cp inclusions in AD retinas and brains, respectively, with no significant increases in MCI retinas or brains. Mass spectrometry-based proteomics in additional cohorts (n=30), revealed dysregulated brain and retinal bacterial infection-related proteins and inflammasome-associated pathways. Retinal Cp was strongly linked to Aβ\u003csub\u003e42\u003c/sub\u003e, caspase-1 and NLRP3-inflammasome activation components, as well as cleaved caspase-3\u003csup\u003e+\u003c/sup\u003e apoptosis and cleaved gasdermin D pyroptotic cell death. Despite increased IBA1\u003csup\u003e+\u003c/sup\u003e microgliosis in the AD retina, the Cp-associated microglial population was reduced by 62%, suggesting impaired microglial phagocytosis. Higher retinal Cp burden correlated with APOEε4 status, advanced Braak stage, and cognitive decline. Machine learning models revealed that retinal Cp or NLRP3, in combination with retinal Aβ\u003csub\u003e42\u003c/sub\u003e, effectively predicted AD diagnosis, Braak stage, and cognition. These findings suggest that Cp infection contributes to AD dementia but is unlikely to initiate AD pathological changes, whereas elevated retinal NLRP3 may serve as an early AD marker. 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