Recombinant Filaggrin Is Internalized and Processed to Correct Filaggrin Deficiency

• Published in: Journal of investigative dermatology Vol. 134; no. 2; pp. 423 - 429
• Main Authors: Stout, Thomas E., McFarland, Trevor, Mitchell, John C., Appukuttan, Binoy, Timothy Stout, J.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-02-2014; Elsevier Limited
• Subjects: Animal models; Animals; Dermatitis, Atopic - genetics; Dermatitis, Atopic - metabolism; Dermatitis, Atopic - therapy; Dermis - cytology; Dermis - metabolism; Epidermis - cytology; Epidermis - metabolism; Genetic Therapy - methods; HEK293 Cells; Humans; Intermediate Filament Proteins - deficiency; Intermediate Filament Proteins - genetics; Intermediate Filament Proteins - pharmacokinetics; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Phenotype; Recombinant Proteins - genetics; Recombinant Proteins - pharmacokinetics
• ISSN: 0022-202X; 1523-1747
• DOI: 10.1038/jid.2013.284

This study was designed to engineer a functional filaggrin (FLG) monomer linked to a cell-penetrating peptide (RMR) and to test the ability of this peptide to penetrate epidermal tissue as a therapeutic strategy for genetically determined atopic dermatitis (AD). A single repeat of the murine filaggrin gene (Flg) was covalently linked to a RMR motif and cloned into a bacterial expression system for protein production. Purified FLG+RMR (mFLG+RMR) was applied in vitro to HEK-293T cells and a reconstructed human epidermis (RHE) tissue model. Immunochemistry demonstrated RMR-dependent cellular uptake of FLG+RMR in a dose- and time-dependent manner in HEK cells. Immunohistochemical staining of the RHE model identified penetration of FLG+RMR to the stratum granulosum, the epidermal layer at which FLG deficiency is thought to be pathologically relevant. In vivo application of FLG+RMR to FLG-deficient flaky tail (ft/ft) mice skin demonstrated internalization and processing of recombinant FLG+RMR to restore the normal phenotype. These results suggest that topically applied RMR-linked FLG monomers are able to penetrate epidermal tissue, be internalized into the appropriate cell type, and be processed to a size similar to wild-type functional barrier peptides to restore necessary barrier function, and prove to be therapeutic for patients with AD.