{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"bioRxiv"}],"indexed":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T16:13:26Z","timestamp":1788192806859,"version":"build-2803163510"},"posted":{"date-parts":[[2026,6,29]]},"group-title":"Synthetic Biology","reference-count":38,"publisher":"openRxiv","license":[{"start":{"date-parts":[[2026,6,29]],"date-time":"2026-06-29T00:00:00Z","timestamp":1782691200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"award":["EB030015"],"award-info":[{"award-number":["EB030015"]}],"id":[{"id":"https:\/\/ror.org\/01cwqze88","id-type":"ROR","asserted-by":"publisher"}]},{"name":"G. Harold & Leila Y. Mathers Foundation","award":["12540447"],"award-info":[{"award-number":["12540447"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2026,8,27]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                <jats:p>The immune system uses paracrine signaling to spatially confine potent responses such as inflammation. A bio-orthogonal synthetic paracrine system could enable engineering of analogous multicellular circuits in which different cell types coordinate their functions in a spatially organized fashion. Here, using the plant hormone auxin as a bio-orthogonal chemical signal, we introduce programmable paracrine circuits that distribute sensing and effector functions to different cell types to spatially restrict responses in mouse xenografts. Cells engineered to express auxin biosynthetic genes generated auxin-dense regions with tunable length scales in vivo. This localized signaling ability enabled design of a multicellular sentinel-effector system, in which THP-1 sentinel cells conditionally produce auxin in regions expressing the tumor-specific antigen EGFRvIII, and Jurkat effector cells respond by locally modulating the activity of a chimeric antigen receptor (CAR). This two-cell type system was able to achieve localized activation of engineered effector cells in vivo. These results establish a foundation for engineering multicellular therapeutic systems that focus responses in specific tissue contexts or disease sites.<\/jats:p>","DOI":"10.64898\/2026.06.26.734902","type":"posted-content","created":{"date-parts":[[2026,6,29]],"date-time":"2026-06-29T13:20:23Z","timestamp":1782739223000},"source":"Crossref","is-referenced-by-count":0,"title":["In vivo spatial coordination with synthetic paracrine signaling"],"prefix":"10.64898","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1597-1219","authenticated-orcid":false,"given":"Kaiwen","family":"Luo","sequence":"first","affiliation":[{"name":"Division of Biology and Bioengineering, California Institute of Technology"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4446-7326","authenticated-orcid":false,"given":"Yitong","family":"Ma","sequence":"additional","affiliation":[{"name":"Department of Bioengineering, Stanford University"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6970-0230","authenticated-orcid":false,"given":"Hongyi R.","family":"Li","sequence":"additional","affiliation":[{"name":"Division of Biology and Bioengineering, California Institute of Technology"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-7761-1317","authenticated-orcid":false,"given":"Hengyu","family":"Li","sequence":"additional","affiliation":[{"name":"Division of Chemistry and Chemical Engineering, California Institute of Technology"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0007-0290-2170","authenticated-orcid":false,"given":"Mengziang","family":"Lei","sequence":"additional","affiliation":[{"name":"Division of Biology and Bioengineering, California Institute of Technology"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9610-0687","authenticated-orcid":false,"given":"Margaret B.","family":"Swift","sequence":"additional","affiliation":[{"name":"Division of Chemistry and Chemical Engineering, California Institute of Technology"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2059-1587","authenticated-orcid":false,"given":"Nathan F.","family":"Dalleska","sequence":"additional","affiliation":[{"name":"Division of Geological and Planetary Sciences, California Institute of Technology"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Abdullah S.","family":"Farooq","sequence":"additional","affiliation":[{"name":"Division of Biology and Bioengineering, California Institute of Technology"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9086-9129","authenticated-orcid":false,"given":"Ernesto","family":"Criado-Hidalgo","sequence":"additional","affiliation":[{"name":"Division of Chemistry and Chemical Engineering, California Institute of Technology"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0908-3506","authenticated-orcid":false,"given":"Ann","family":"Liu","sequence":"additional","affiliation":[{"name":"Division of Biology and Bioengineering, California Institute of Technology"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0291-4215","authenticated-orcid":false,"given":"Mikhail G.","family":"Shapiro","sequence":"additional","affiliation":[{"name":"Division of Chemistry and Chemical Engineering, California Institute of Technology"},{"name":"Andrew and Peggy Cherng Department of Medical Engineering, California Institute of Technology"},{"name":"Howard Hughes Medical Institute, California Institute of Technology"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1221-0967","authenticated-orcid":false,"given":"Michael B.","family":"Elowitz","sequence":"additional","affiliation":[{"name":"Division of Biology and Bioengineering, California Institute of Technology"},{"name":"Division of Engineering and Applied Science, California Institute of Technology"},{"name":"Howard Hughes Medical Institute, California Institute of Technology"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"54368","reference":[{"key":"2026083108151420000_2026.06.26.734902v2.1","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMra2026131"},{"key":"2026083108151420000_2026.06.26.734902v2.2","doi-asserted-by":"publisher","DOI":"10.1172\/JCI34431"},{"key":"2026083108151420000_2026.06.26.734902v2.3","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1016\/j.coisb.2019.10.011","article-title":"Stimulus-specificity in the responses of immune sentinel cells","volume":"18","year":"2019","journal-title":"Curr. 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