title: Controlling transgene expression in subcutaneous implants using a skin lotion containing the apple metabolite phloretin.
abstract: Adjustable control of therapeutic transgenes in engineered cell implants after transdermal and topical delivery of nontoxic trigger molecules would increase convenience, patient compliance, and elimination of hepatic first-pass effect in future therapies. Pseudomonas putida DOT-T1E has evolved the flavonoid-triggered TtgR operon, which controls expression of a multisubstrate-specific efflux pump (TtgABC) to resist plant-derived defense metabolites in its rhizosphere habitat. Taking advantage of the TtgR operon, we have engineered a hybrid P. putida-mammalian genetic unit responsive to phloretin. This flavonoid is contained in apples, and, as such, or as dietary supplement, regularly consumed by humans. The engineered mammalian phloretin-adjustable control element (PEACE) enabled adjustable and reversible transgene expression in different mammalian cell lines and primary cells. Due to the short half-life of phloretin in culture, PEACE could also be used to program expression of difficult-to-produce protein therapeutics during standard bioreactor operation. When formulated in skin lotions and applied to the skin of mice harboring transgenic cell implants, phloretin was able to fine-tune target genes and adjust heterologous protein levels in the bloodstream of treated mice. PEACE-controlled target gene expression could foster advances in biopharmaceutical manufacturing as well as gene- and cell-based therapies.
authors: Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule Zürich, Mattenstrasse 26, CH-4058 Basel, Switzerland.
authors: Marc
authors: M
authors: Gitzinger
authors: Christian
authors: C
authors: Kemmer
authors: Marie Daoud
authors: MD
authors: El-Baba
authors: Wilfried
authors: W
authors: Weber
authors: Martin
authors: M
authors: Fussenegger
mesh_terms: D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism; D000818:Animals; D016466:CHO Cells; D019556:COS Cells; D002460:Cell Line; D045744:Cell Line, Tumor; D017690:Cell Transplantation / Q000379:methods*; D002522:Chlorocebus aethiops; D006224:Cricetinae; D003412:Cricetulus; D003879:Dermatologic Agents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005419:Flavonoids / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects*; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D027845:Malus / Q000378:metabolism; D051379:Mice; D041681:NIH 3T3 Cells; D009876:Operon / Q000235:genetics; D010693:Phloretin / Q000494:pharmacology*; D016958:Pseudomonas putida / Q000235:genetics; D020218:Response Elements / Q000235:genetics; D014162:Transfection; D019076:Transgenes / Q000235:genetics*
chemical_list: D003879:Dermatologic Agents; D005419:Flavonoids; D000469:Alkaline Phosphatase; D010693:Phloretin