{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,21]],"date-time":"2026-10-21T18:37:59Z","timestamp":1792607879732,"version":"4.5.0"},"reference-count":45,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,5,27]],"date-time":"2026-05-27T00:00:00Z","timestamp":1779840000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100007190","name":"Unilever","doi-asserted-by":"publisher","award":["MA-2023-00556N"],"award-info":[{"award-number":["MA-2023-00556N"]}],"id":[{"id":"10.13039\/100007190","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Toxicol."],"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>As part of a programme of work developing human-relevant New Approach Methodologies (NAMs) for next-generation risk assessment (NGRA), use of a human air-liquid interface (ALI) bronchial epithelial model (MucilAir\u2122) to investigate the impact of exposure to protease was assessed.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      To guide\n                      <jats:italic>in vitro<\/jats:italic>\n                      dosing, scenarios representing low-high risk of sensitisation after 8\u00a0h of protease exposure in an occupational setting were modelled by performing simulations with the Multiple Path Particle Dosimetry (MPPD) model with refinement of the outputs using a tracheobronchial\/alveolar clearance model, to estimate tracheobronchial tissue doses. With no effects seen at these concentrations, higher concentrations were subsequently tested to identify thresholds for biological effects. Repeated apical liquid exposures over 8\u00a0h were applied using a wide concentration range of protease (0.00125\u20137812\u00a0\u03bcg protease protein\/mL) or phosphate-buffered saline (PBS) control. Effects on epithelial barrier integrity, cytokine production, and extracellular vesicle (EV) dynamics were measured.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Reduced transepithelial electrical resistance (TEER), increased EV and IL-8 secretion were observed using a PBS control reflecting the impact of liquid dosing alone. No significant protease-related adverse effects were observed at concentrations of 0.5\u00a0\u03bcg protease protein\/mL or lower when compared to the PBS control. At concentrations of 75\u00a0\u03bcg protease protein\/mL or more, however, TEER was significantly reduced and mucin and tetraspanin expression on EVs was degraded.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Discussion<\/jats:title>\n                    <jats:p>\n                      Here, we show the impact of liquid dosing when investigating the effects of materials on bronchial epithelia, and challenges encountered when working with proteases. This work provides a foundation for developing\n                      <jats:italic>in vitro<\/jats:italic>\n                      methodology for generation of data for use in risk assessment of inhalation of enzymes and other materials. It is hypothesised that nebulised protease delivery could be a more suitable alternative and better replicate\n                      <jats:italic>in vivo<\/jats:italic>\n                      (human) inhalation dynamics.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/ftox.2026.1781231","type":"journal-article","created":{"date-parts":[[2026,5,27]],"date-time":"2026-05-27T02:09:06Z","timestamp":1779847746000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":2,"title":["Impact of liquid dosing and associated cell \u2018drowning\u2019 in a 3D human bronchial epithelial model used for protease exposure studies"],"prefix":"10.3389","volume":"8","author":[{"given":"Georgina","family":"Hopkins","sequence":"first","affiliation":[{"name":"School of Life Sciences, The University of Nottingham","place":["Nottingham, United Kingdom"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David","family":"Sheffield","sequence":"additional","affiliation":[{"name":"SERS, Unilever, Colworth Science Park","place":["Sharnbrook, United Kingdom"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hugh","family":"Barlow","sequence":"additional","affiliation":[{"name":"SERS, Unilever, Colworth Science Park","place":["Sharnbrook, United Kingdom"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anja","family":"Lalljie","sequence":"additional","affiliation":[{"name":"SERS, Unilever, Colworth Science Park","place":["Sharnbrook, United Kingdom"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stella","family":"Cochrane","sequence":"additional","affiliation":[{"name":"SERS, Unilever, Colworth Science Park","place":["Sharnbrook, United Kingdom"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lucy C","family":"Fairclough","sequence":"additional","affiliation":[{"name":"School of Life Sciences, The University of Nottingham","place":["Nottingham, United Kingdom"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,5,27]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"364","DOI":"10.1093\/occmed\/kqr107","article-title":"Occupational asthma and rhinitis due to detergent enzymes in healthcare","volume":"61","author":"Adisesh","year":"2011","journal-title":"Occup. 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