title: Larazotide acetate regulates epithelial tight junctions in vitro and in vivo.
abstract: Tight junctions (TJs) control paracellular permeability and apical-basolateral polarity of epithelial cells, and can be regulated by exogenous and endogenous stimuli. Dysregulated permeability is associated with pathological conditions, such as celiac disease and inflammatory bowel disease. Herein we studied the mechanism by which larazotide acetate, an 8-mer peptide and TJ regulator, inhibits the cellular changes elicited by gliadin fragments, AT-1002, and cytokines. Previously, we demonstrated that AT-1002, a 6-mer peptide derived from the Vibrio cholerae zonula occludens toxin ZOT, caused several biochemical changes in IEC6 and Caco-2 cells resulting in decreased transepithelial electrical resistance (TEER) and increased TJ permeability. In this study, larazotide acetate inhibited the redistribution and rearrangement of zonula occludens-1 (ZO-1) and actin caused by AT-1002 and gliadin fragments in Caco-2 and IEC6 cells. Functionally, larazotide acetate inhibited the AT-1002-induced TEER reduction and TJ opening in Caco-2 cells. Additionally, larazotide acetate inhibited the translocation of a gliadin 13-mer peptide, which has been implicated in celiac disease, across Caco-2 cell monolayers. Further, apically applied larazotide acetate inhibited the increase in TJ permeability elicited by basolaterally applied cytokines. Finally, when tested in vivo in gliadin-sensitized HLA-HCD4/DQ8 double transgenic mice, larazotide acetate inhibited gliadin-induced macrophage accumulation in the intestine and preserved normal TJ structure. Taken together, our data suggest that larazotide acetate inhibits changes elicited by AT-1002, gliadin, and cytokines in epithelial cells and preserves TJ structure and function in vitro and in vivo.
authors.affiliation: ALBA Therapeutics, 650 S. Exeter, Suite 1040, 10th Floor, Baltimore, MD 21202, United States.
authors.forename: Shobha
authors.initials: S
authors.lastname: Gopalakrishnan
authors.forename: Malarvizhi
authors.initials: M
authors.lastname: Durai
authors.forename: Kelly
authors.initials: K
authors.lastname: Kitchens
authors.forename: Amir P
authors.initials: AP
authors.lastname: Tamiz
authors.forename: Robert
authors.initials: R
authors.lastname: Somerville
authors.forename: Mark
authors.initials: M
authors.lastname: Ginski
authors.forename: Blake M
authors.initials: BM
authors.lastname: Paterson
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Murray
authors.forename: Elena F
authors.initials: EF
authors.lastname: Verdu
authors.forename: Sefik S
authors.initials: SS
authors.lastname: Alkan
authors.forename: Niranjan B
authors.initials: NB
authors.lastname: Pandey
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D018938:Caco-2 Cells; D002446:Celiac Disease / Q000139:chemically induced / Q000188:drug therapy / Q000473:pathology; D016207:Cytokines / Q000494:pharmacology; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism; D005903:Gliadin / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000187:drug effects; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D009842:Oligopeptides / Q000494:pharmacology* / Q000627:therapeutic use; D010539:Permeability / Q000187:drug effects; D010750:Phosphoproteins / Q000378:metabolism; D051381:Rats; D019108:Tight Junctions / Q000187:drug effects* / Q000378:metabolism; D062826:Zonula Occludens-1 Protein
chemical_list: D000199:Actins; D016207:Cytokines; D008565:Membrane Proteins; D009842:Oligopeptides; D010750:Phosphoproteins; C569042:TJP1 protein, human; C569043:Tjp1 protein, mouse; C569044:Tjp1 protein, rat; D062826:Zonula Occludens-1 Protein; D005903:Gliadin; C525167:larazotide acetate