Inhibiting complex IL-17A and IL-17RA interactions with a linear peptide

Abstract

IL-17A is a pro-inflammatory cytokine that has been implicated in autoimmune and inflammatory diseases. Monoclonal antibodies inhibiting IL-17A signaling have demonstrated remarkable efficacy, but an oral therapy is still lacking. A high affinity IL-17A peptide antagonist (HAP) of 15 residues was identified through phage-display screening followed by saturation mutagenesis optimization and amino acid substitutions. HAP binds specifically to IL-17A and inhibits the interaction of the cytokine with its receptor, IL-17RA. Tested in primary human cells, HAP blocked the production of multiple inflammatory cytokines. Crystal structure studies revealed that two HAP molecules bind to one IL-17A dimer symmetrically. The N-terminal portions of HAP form a β-strand that inserts between two IL-17A monomers while the C-terminal section forms an α helix that directly blocks IL-17RA from binding to the same region of IL-17A. This mode of inhibition suggests opportunities for developing peptide antagonists against this challenging target.

Isolation of Chemically Cyclized Peptide Binders Using Yeast Surface Display

“…Several autoimmune diseases, like plaque psoriasis and psoriatic arthritis, are characterized by excessive levels of IL-17 24 . Cyclic peptides specific to IL-17 can potentially be used as labeling agents 25 or inhibitors of the IL-17:IL-17RA interaction 26 .…”

Turning a Substrate Peptide into a Potent Inhibitor for the Histone Methyltransferase SETD8

“…For the C-terminus, L22 sits in a largely hydrophobic pocket with some charge on the periphery. Peptides with largely hydrophobic substitutions at L22 (beta-cyclohexylalanine (15), (19)) tended to bind well, but only the beta-cyclohexylalanine (15) substitution peptide (20) and L-methionine sulfone (22)) in an attempt to interact with charged groups on the periphery of the pocket was not successful and weakened or eliminated binding.…”

“…Only the top dozen candidates with the best global fit were selected for subsequent synthesis and NMR screening. The following H4 (16−23) norleucine substituted peptides were then selected for binding studies by ITC: peptides KRHR(Nle)VLR with R17 substitution L-homoleucine (11), tert-butyl-L-cysteine (12), isoleucine (13), and methionine (14) and the peptides KRHR(Nle)VLR with L22 substitution betacyclohexylalanine (15), L-homoleucine (21), and L-methionine sulfone (22). The results for the substitution of R17 are shown in Table 2 and for L22 in Table 3.…”

“…Inhibitors derived from peptides have been developed for other targets of potential therapeutic importance such as IAPs, 18 beta secretase, 19 14−3−3 proteins, 20 the Bcl family of proteins, 21 and IL-17A. 22 With this in mind, and based on a careful analysis of the structure of the bound substrate peptide, 2 we have designed a potent peptide-based inhibitor of SETD8, which will be useful not only as an in vitro tool to further study SETD8 function but also can potentially be turned into a potent cell-penetrant inhibitor for in vivo studies of SETD8 inhibition.…”

Artificial macrocycles as IL-17A/IL-17RA antagonists

“…Recently H/D exchange MS was used to determine the binding region of macrocycle 1 on IL-17A, which is predicted to bind to the β-hairpin pocket 26 . Another group from Pfizer designed potent derivatives macrocycles 2 and 3 and elucidated their high-resolution co-crystal structure with IL-17A 27, 28 . Both compounds bind into the homodimeric interface.…”