Structure‐based derivation of peptide inhibitors to target TGF‐β1 receptor for the suppression of hypertrophic scarring fibroblast activation

Abstract

The intermolecular recognition and interaction between human transforming growth factor β-1 (TGF-β1) and its cognate receptor TβRII have been implicated in the pathological condition of hypertrophic scarring (HS). Here, we attempted to rationally derive peptide inhibitors from the complex interface of TGF-β1 with TβRII to disrupt such interaction for the suppression of fibroblast activation involved in HS. A synthetic strategy that integrated computational design and fluorescence-based assay was described to examine the structural basis and energetic property of TGF-β1-TβRII crystal structure, from which a small peptide segment in the complex binding site was stripped artificially. Molecular dynamics simulations revealed that the linear peptide possesses a large intrinsic disorder that would incur considerable entropy penalty upon binding to TβRII; the peptide segment was then extended and cyclized by introducing a disulfide bond across its terminal residues that were premutated to cysteine. Normal mode analysis indicated that, as expected, the peptide flexibility was largely reduced upon the cyclization, and thus, the entropy penalty was minimized substantially, consequently promoting the spontaneous binding of peptide to TβRII. Fluorescence polarization assay confirmed that all linear peptides are typical non-binders of TβRII (K = ND), while the designed cyclic peptides exhibit moderate or high affinity with K at micromolar level.

Comparative peptidomic profile between human hypertrophic scar tissue and matched normal skin for identification of endogenous peptides involved in scar pathology

“…S100A7 (psoriasin) and S100A15 (koebnerisin), firstly identified in inflamed psoriatic skin (Wolf, Ruzicka, & Yuspa, ), could suppress extracellular matrix production, and proliferation of human fibroblasts (Gauglitz, Bureik, Zwicker, Ruzicka, & Wolf, ). Structure‐based derivation of peptide inhibitors could target TGF‐β1 Receptor for the suppression of hypertrophic scarring fibroblast activation (Hu, Yang, Zheng, & Mao, ). In the present study, with peptidomics analysis on hypertrophic scar tissue, a total of 179 differentially expressed peptides derived from 66 precursor proteins were identified compared with matched normal skin.…”

Structure‐based discovery and redesign of TGF‐β1 Elbow epitope recognition by its type‐II receptor in hypertrophic scarring biotherapy

“…The fluorescence polarization (FP) assays were performed at 298 K following a protocol modified from our previous report 10 . Briefly, all peptides were obtained from solid phase peptide synthesis and labeled with fluorescein.…”

“…Instead, the TGF‐β1 adopts a distinct surface region to interact with TβR‐II, which is composed of two spatially vicinal protein segments and thus spans between the linear and conformational epitopes; we herein called this region as elbow epitope to extend the traditional notion of wrist and knuckle epitopes. Previously, we proposed targeting the TGF‐β1‐TβRII interaction as a potential therapeutic strategy to combat HS at molecular level 10 . Here, we systematically investigated the elbow epitope of TGF‐β1 interaction with TβRII at structural level and identified the minimal composition of the epitope region, from which we derived several protein segments and combined/optimized them to rationally deign the linear peptide mimics of the epitope, which could be exploited as potential peptide inhibitors to competitively disrupt the TGF‐β1‐TβRII interaction for HS biotherapy.…”

The Effects of the Transforming Growth Factor-β1 (TGF-β1) Signaling Pathway on Cell Proliferation and Cell Migration are Mediated by Ubiquitin Specific Protease 4 (USP4) in Hypertrophic Scar Tissue and Primary Fibroblast Cultures

“…Transforming growth factor b1 (TGF-b1) signaling plays a vital role in the formation of hypertrophic scar, and is initiated by the binding of TGF-b1 to TGF-b receptor type 1 (TGF-bR1) in the cell membrane to form a complex [7,8]. The binding of TGF-b1 to the TGF-b1 receptor complex on the cell surface initiates cellular functions associated with the activation of intracellular Smad signaling proteins [9].…”