Targeted delivery of anti-inflammatory therapy to rheumatoid tissue by fusion proteins containing an IL-4-linked synovial targeting peptide

We provide first-time evidence that the synovial endothelium-targeting peptide (SyETP) CKSTHDRLC successfully delivers conjugated IL-4 to human rheumatoid synovium transplanted into SCID mice. SyETP, previously isolated by in vivo phage display and shown to preferentially localize to synovial xenografts, was linked by recombinant technology to hIL-4 via an MMP-cleavable sequence. Both IL-4 and the MMP-cleavable sequence were shown to be functional. IL-4-SyETP augmented production of IL-1ra by synoviocytes stimulated with IL-1[beta] in a dose-dependent manner. In vivo imaging confirmed increased retention of SyETP-linked-IL-4 in synovial grafts which was enhanced by increasing number of copies (one to three) in the constructs. Strikingly, SyETP delivered bioactive IL-4 in vivo as demonstrated by increased pSTAT6 in synovial grafts. Thus, this study provides proof of concept for peptide-tissue-specific targeted immunotherapy in rheumatoid arthritis. This technology is potentially applicable to other biological therapies providing enhanced potency to inflammatory sites and reducing systemic toxicity

Targeting alpha v beta 6 integrin for cancer imaging

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Developing antagonists for the Met-HGF/SF protein-protein interaction using a fragment-based approach

In many cancers, aberrant activation of the Met receptor tyrosine kinase leads to dissociation of cells from the primary tumor, causing metastasis. Accordingly, Met is a high-profile target for the development of cancer therapies, and progress has been made through development of small molecule kinase inhibitors and antibodies. However, both approaches pose significant challenges with respect to either target specificity (kinase inhibitors) or the cost involved in treating large patient cohorts (antibodies). Here, we use a fragment-based approach in order to target the protein-protein interaction (PPI) between the α-chain of hepatocyte growth factor/scatter factor (HGF/SF; the NK1 fragment) and its high-affinity binding site located on the Met Sema domain. Surface plasmon resonance was used for initial fragment library screening and hits were developed into larger compounds using substructure (similarity) searches. We identified compounds able to interfere with NK1 binding to Met, disrupt Met signaling, and inhibit tumorsphere generation and cell migration. Using molecular docking, we concluded that some of these compounds inhibit the PPI directly, whereas others act indirectly. Our results indicate that chemical fragments can efficiently target the HGF/SF-Met interface and may be used as building blocks for generating biologically active lead compounds. This strategy may have broad application for the development of a new class of Met inhibitors, namely receptor antagonists, and in general for the development of small molecule PPI inhibitors of key therapeutic targets when structural information is not available

Foot-and-mouth disease virus forms a highly stable, EDTA-resistant complex with its principal receptor, integrin alpha v beta 6: Implications for infectiousness

The initial stage of foot-and-mouth disease virus (FMDV) infection is virus binding to cell surface integrins via the RGD motif in the GH loop of the VP1 capsid protein. As for all ligand/integrin interactions, the initial contact between FMDV and its integrin receptors is cation dependent and hence inhibited by EDTA. We have investigated this binding process with RGD-containing peptides derived from the VP1 capsid protein of FMDV and discovered that, upon binding, some of these peptides form highly stable, EDTA-resistant associations with integrin alpha v beta 6. Peptides containing specific substitutions show that this stable binding is dependent on a helical structure immediately C terminal to the RGD and, specifically, two leucine residues at positions RGD +1 and RGD +4. These observations have a biological consequence, as we show further that stable, EDTA-resistant binding to alpha v beta 6 is a property also exhibited by FMDV particles. Thus, the integrin-binding loop of FMDV appears to have evolved to form very stable complexes with the principal receptor of FMDV, integrin alpha v beta 6. An ability to induce such stable complexes with its cellular receptor is likely to contribute significantly to the high infectiousness of FMDV

Structure-function analysis of Arg-Gly-Asp helix motifs in alpha v beta 6 integrin ligands

Data relating to the structural basis of ligand recognition by integrins are limited. Here we describe the physical requirements for high affinity binding of ligands to alpha v beta 6. By combining a series of structural analyses with functional testing, we show that 20-mer peptide ligands, derived from high affinity ligands of alpha v beta 6 (foot-and-mouth-disease virus, latency associated peptide), have a common structure comprising an Arg-Gly-Asp motif at the tip of a hairpin turn followed immediately by a C-terminal helix. This arrangement allows two conserved Leu/Ile residues at Asp(+1) and Asp(+4) to be presented on the outside face of the helix enabling a potential hydrophobic interaction with the alpha v beta 6 integrin, in addition to the Arg-Gly-Asp interaction. The extent of the helix determines peptide affinity for alpha v beta 6 and potency as an alpha v beta 6 antagonist. A major role of this C-terminal helix is likely to be the correct positioning of the Asp(+1) and Asp(+4) residues. These data suggest an explanation for several biological functions of alpha v beta 6 and provide a structural platform for design of alpha v beta 6 antagonists

α-helix and 3₁₀-helix Library design.

<p>A) Amino acid sequence and NMR solution structure of A20FMDV2 with a hairpin structure with RGD at the tip of the turn followed by a C-terminal helix is shown. B) α-helix algorithm used to design the V_H-CDR3 encoding a hairpin containing at its turn an RGD motif, followed by a C-terminal α-helix. C) 3₁₀-helix algorithm used to designed the V_H-CDR3 encoding a hairpin containing at its turn an RGD motif, followed by a C-terminal 3₁₀-helix. Amino acid positions that are available for randomisation are highlighted (X and Z shown in blue and red, respectively).</p

Oligonucleotides used to build the structural guided library.

<p>Oligonucleotides used to build the structural guided library.</p