Paracellular permeation-enhancing effect of AT1002 C-terminal amidation in nasal delivery

Abstract

BackgroundThe identification of permeation enhancers has gained interest in the development of drug delivery systems. A six-mer peptide, H-FCIGRL-OH (AT1002), is a tight junction modulator with promising permeation-enhancing activity. AT1002 enhances the transport of molecular weight markers or agents with low bioavailability with no cytotoxicity. However, AT1002 is not stable in neutral pH or after incubation under physiological conditions, which is necessary to fully uncover its permeation-enhancing effect. Thus, we increased the stability or mitigated the instability of AT1002 by modifying its terminal amino acids and evaluated its subsequent biological activity.MethodsC-terminal-amidated (FCIGRL-NH2, Pep1) and N-terminal-acetylated (Ac-FCIGRL, Pep2) peptides were analyzed by liquid chromatography–mass spectrometry. We further assessed cytotoxicity on cell monolayers, as well as the permeation-enhancing activity following nasal administration of the paracellular marker mannitol.ResultsPep1 was nontoxic to cell monolayers and showed a relatively low decrease in peak area compared to AT1002. In addition, administration of mannitol with Pep1 resulted in significant increases in the area under the plasma concentration–time curve and peak plasma concentration at 3.63-fold and 2.68-fold, respectively, compared to mannitol alone. In contrast, no increase in mannitol concentration was shown with mannitol/AT1002 or mannitol/Pep2 compared to the control. Thus, Pep1 increased the stability or possibly reduced the instability of AT1002, which resulted in an increased permeation-enhancing effect of AT1002.ConclusionThese results suggest the potential usefulness of C-terminal-amidated AT1002 in enhancing nasal drug delivery, which may lead to the development of a practical drug delivery technology for drugs with low bioavailability.

Anti-RelA siRNA-Encapsulated Flexible Liposome with Tight Junction-Opening Peptide as a Non-invasive Topical Therapeutic for Atopic Dermatitis

“…AT1002 also activates ΔG and the zonula occludens toxin. [24][25][26][27] Our previous study confirmed that AT1002 enhances the delivery of topically applied siRNA., and deeper dermal siRNA penetration can substantially improve its efficacy at treating skin diseases such as AD. 9,12,28) The target protein selected for AD treatment in this study was NF-κB (RelA).…”

Development of an Innovative Intradermal siRNA Delivery System Using a Combination of a Functional Stearylated Cytoplasm-Responsive Peptide and a Tight Junction-Opening Peptide

“…Tight junctions are cell junctions that connect neighboring cells and control the paracellular pathway of molecules. AT1002 is a hexamer synthetic peptide (H-FCIGRL-OH), which reversibly opens the tight junctions of the stratum granulosum and has biological activity similar to ΔG and zonula occludens toxin, increasing the paracellular transport of drugs across the epithelial barrier [18,19,20,21]. We have reported that the application of AT1002 can reversibly open tight junctions and increase intradermal siRNA delivery [22].…”

Biomaterials-Enhanced Intranasal Delivery of Drugs as a Direct Route for Brain Targeting

“…The peptide AT1002 is an analog of Vibrio cholera toxin, acting on zonula occludens in tight junctions. Peptide AT1002 enhances IN permeation by binding its receptor reversibly and opening tight junctions [ 40 ].…”