title: Mechanism of action of ZOT-derived peptide AT-1002, a tight junction regulator and absorption enhancer.
abstract: Tight junctions (TJs) are intercellular structures that control paracellular permeability and epithelial polarity. It is now accepted that TJs are highly dynamic structures that are regulated in response to exogenous and endogenous stimuli. Here, we provide details on the mechanism of action of AT-1002, the active domain of Vibrio cholerae's second toxin, zonula occludens toxin (ZOT). AT-1002, a hexamer peptide, caused the redistribution of ZO-1 away from cell junctions as seen by fluorescence microscopy. AT-1002 also activated src and mitogen activated protein (MAP) kinase pathways, increased ZO-1 tyrosine phosphorylation, and rearrangement of actin filaments. Functionally, AT-1002 caused a reversible reduction in transepithelial electrical resistance (TEER) and an increase in lucifer yellow permeability in Caco-2 cell monolayers. In vivo, co-administration of salmon calcitonin with 1 mg of AT-1002 resulted in a 5.2-fold increase in AUC over the control group. Our findings provide a mechanistic explanation for AT-1002-induced tight junction disassembly, and demonstrate that AT-1002 can be used for delivery of other agents in vivo.
authors.affiliation: Alba Therapeutics, 800 W. Baltimore Street, Suite 400, Baltimore, MD 21201, United States.
authors.forename: Shobha
authors.initials: S
authors.lastname: Gopalakrishnan
authors.forename: Niranjan
authors.initials: N
authors.lastname: Pandey
authors.forename: Amir P
authors.initials: AP
authors.lastname: Tamiz
authors.forename: John
authors.initials: J
authors.lastname: Vere
authors.forename: Rosa
authors.initials: R
authors.lastname: Carrasco
authors.forename: Robert
authors.initials: R
authors.lastname: Somerville
authors.forename: Amit
authors.initials: A
authors.lastname: Tripathi
authors.forename: Mark
authors.initials: M
authors.lastname: Ginski
authors.forename: Blake M
authors.initials: BM
authors.lastname: Paterson
authors.forename: Sefik S
authors.initials: SS
authors.lastname: Alkan
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D000199:Actins / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D019540:Area Under Curve; D018938:Caco-2 Cells; D002116:Calcitonin / Q000493:pharmacokinetics; D002772:Cholera Toxin / Q000737:chemistry*; D004347:Drug Interactions; D017097:Electric Impedance; D004731:Endotoxins; D006801:Humans; D007546:Isoquinolines / Q000378:metabolism; D008297:Male; D008856:Microscopy, Fluorescence; D020928:Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D019108:Tight Junctions / Q000187:drug effects* / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism; D019061:src-Family Kinases / Q000187:drug effects / Q000378:metabolism
chemical_list: C530561:AT1002; D000199:Actins; D004731:Endotoxins; D007546:Isoquinolines; D009842:Oligopeptides; C077728:zonula occludens toxin, Vibrio cholerae; D014443:Tyrosine; C028815:salmon calcitonin; D002116:Calcitonin; D002772:Cholera Toxin; C017475:lucifer yellow; D019061:src-Family Kinases; D020928:Mitogen-Activated Protein Kinases