eprintid: 10141376 rev_number: 12 eprint_status: archive userid: 608 dir: disk0/10/14/13/76 datestamp: 2022-01-07 11:54:50 lastmod: 2022-01-07 11:54:50 status_changed: 2022-01-07 11:54:50 type: article metadata_visibility: show creators_name: Hoijman, E creators_name: Häkkinen, H-M creators_name: Tolosa-Ramon, Q creators_name: Jiménez-Delgado, S creators_name: Wyatt, C creators_name: Miret-Cuesta, M creators_name: Irimia, M creators_name: Callan-Jones, A creators_name: Wieser, S creators_name: Ruprecht, V title: Cooperative epithelial phagocytosis enables error correction in the early embryo ispublished: pub divisions: UCL divisions: B02 divisions: C08 divisions: D09 divisions: F99 note: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. abstract: Errors in early embryogenesis are a cause of sporadic cell death and developmental failure1,2. Phagocytic activity has a central role in scavenging apoptotic cells in differentiated tissues3-6. However, how apoptotic cells are cleared in the blastula embryo in the absence of specialized immune cells remains unknown. Here we show that the surface epithelium of zebrafish and mouse embryos, which is the first tissue formed during vertebrate development, performs efficient phagocytic clearance of apoptotic cells through phosphatidylserine-mediated target recognition. Quantitative four-dimensional in vivo imaging analyses reveal a collective epithelial clearance mechanism that is based on mechanical cooperation by two types of Rac1-dependent basal epithelial protrusions. The first type of protrusion, phagocytic cups, mediates apoptotic target uptake. The second, a previously undescribed type of fast and extended actin-based protrusion that we call 'epithelial arms', promotes the rapid dispersal of apoptotic targets through Arp2/3-dependent mechanical pushing. On the basis of experimental data and modelling, we show that mechanical load-sharing enables the long-range cooperative uptake of apoptotic cells by multiple epithelial cells. This optimizes the efficiency of tissue clearance by extending the limited spatial exploration range and local uptake capacity of non-motile epithelial cells. Our findings show that epithelial tissue clearance facilitates error correction that is relevant to the developmental robustness and survival of the embryo, revealing the presence of an innate immune function in the earliest stages of embryonic development. date: 2021-02-25 date_type: published official_url: https://doi.org/10.1038/s41586-021-03200-3 oa_status: green full_text_type: other language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 1854208 doi: 10.1038/s41586-021-03200-3 pii: 10.1038/s41586-021-03200-3 lyricists_name: Wyatt, Christopher lyricists_id: CDRWY41 actors_name: Flynn, Bernadette actors_id: BFFLY94 actors_role: owner full_text_status: public publication: Nature volume: 590 number: 7847 pagerange: 618-623 event_location: England citation: Hoijman, E; Häkkinen, H-M; Tolosa-Ramon, Q; Jiménez-Delgado, S; Wyatt, C; Miret-Cuesta, M; Irimia, M; ... Ruprecht, V; + view all <#> Hoijman, E; Häkkinen, H-M; Tolosa-Ramon, Q; Jiménez-Delgado, S; Wyatt, C; Miret-Cuesta, M; Irimia, M; Callan-Jones, A; Wieser, S; Ruprecht, V; - view fewer <#> (2021) Cooperative epithelial phagocytosis enables error correction in the early embryo. Nature , 590 (7847) pp. 618-623. 10.1038/s41586-021-03200-3 <https://doi.org/10.1038/s41586-021-03200-3>. Green open access document_url: https://discovery-pp.ucl.ac.uk/id/eprint/10141376/1/Hoi_Nat_Co.pdf