Expression, purification and characterization of anti-FGF7 domain antibody identified using phage display technique

Background: Fibroblast growth factors (FGFs) are involved in angiogenesis, wound healing and embryonic development. However, one of the causes of cancer cell growth in fibroblast-dependent cancers is FGF7 secreted by fibroblasts. Therefore, antibodies against FGF7 can be used for treatment of these types of cancers. Methods: In previous studies, a phage displaying single domain antibody, D53, against human FGF7 has been identified using the phage display technique. In the present study, D53 was produced and purified in its isolated form. ELISA experiment was performed to evaluate the binding of D53 to FGF7. The mode of interaction of D53-FGF7 was explored using docking study and molecular dynamics (MD) simulations. Results: The expression and purification processes were verified using western blotting and SDS-PAGE analyses. ELISA experiment showed that D53 is able to recognize and bind FGF7. Docking study and MD simulations indicated that compared to dummy VH, D53 has more affinity towards FGF7. Conclusion: The findings in the current study can be useful for generation and development of FGF7 inhibitors with potential use in fibroblast-dependent cancers.

Phage-Display Based Discovery and Characterization of Peptide Ligands against WDR5

WD40 is a ubiquitous domain presented in at least 361 human proteins and acts as scaffold to form protein complexes. Among them, WDR5 protein is an important mediator in several protein complexes to exert its functions in histone modification and chromatin remodeling. Therefore, it was considered as a promising epigenetic target involving in anti-cancer drug development. In view of the protein–protein interaction nature of WDR5, we initialized a campaign to discover new peptide-mimic inhibitors of WDR5. In current study, we utilized the phage display technique and screened with a disulfide-based cyclic peptide phage library. Five rounds of biopanning were performed and isolated clones were sequenced. By analyzing the sequences, total five peptides were synthesized for binding assay. The four peptides are shown to have the moderate binding affinity. Finally, the detailed binding interactions were revealed by solving a WDR5-peptide cocrystal structure.

Bacteriophages as Therapeutic and Diagnostic Vehicles in Cancer

Evolution of nanomedicine is the re-design of synthetic and biological carriers to implement novel theranostic platforms. In recent years, bacteriophage research favors this process, which has opened up new roads in drug and gene delivery studies. By displaying antibodies, peptides, or proteins on the surface of different bacteriophages through the phage display technique, it is now possible to unravel specific molecular determinants of both cancer cells and tumor-associated microenvironmental molecules. Downstream applications are manifold, with peptides being employed most of the times to functionalize drug carriers and improve their therapeutic index. Bacteriophages themselves were proven, in this scenario, to be good carriers for imaging molecules and therapeutics as well. Moreover, manipulation of their genetic material to stably vehiculate suicide genes within cancer cells substantially changed perspectives in gene therapy. In this review, we provide examples of how amenable phages can be used as anticancer agents, especially because their systemic administration is possible. We also provide some insights into how their immunogenic profile can be modulated and exploited in immuno-oncology for vaccine production.

Identification of a porcine TLR2-targeting peptide ligands using a cell-based phage display combined with high-throughput sequencing

M cell targeting is one of the critical issues to develop efficient mucosal vaccine design. In this study, peptide ligands with high affinity to porcine TLR2, which is highly expressed in M cells and play an important role in mucosal immune responses in pigs, were identified through the cell-based phage display technique combined with high-throughput sequencing. A random phage-peptide library was applied to the porcine TLR2 overexpressing cell line and total 85, 557 unique peptide sequences were identified from approximately 9.0 × 107 reads after three rounds of both subtractive and non-subtractive biopanning via high-throughput sequencing. Among the unique sequences, three candidate peptide sequences, NAGHLSQ, VPSKPGL, and RANLDGQ, were selected based on their abundance in the third round of biopanning. Consequently, NAGHLSQ showed the highest affinity exclusively to porcine TLR2 compared with other candidates and its binding mechanism was inferred to be directly associated with ligand binding site of the TLR2 through the in vitro competitive analysis. The peptide identified in this research could be used in development of effective porcine mucosal vaccine as an M cell targeting moiety to enhance the transport of antigens into the Peyer's patch via oral route.

Development of Specific Nano-Antibody for Application in Selective and Rapid Environmental Diagnoses of Salmonella arizonae

Treatment of human and animals for protection from pathogens infection has significant economic value, especially with the harmful Salmonella arizonae. Beneficial cameloid heavy-chain antibodies as single-domain antigen-binding fragments known as VHHs or nano-bodies may be the acceptable option for producing the treatment and/or diagnostic agents. In the current study, we developed a sandwich ELISA based nano-body towards S. arizonae as the first report for the treatment of S. arizonae. using the cDNA synthesized from immunized camels RNA to isolate 700 bp DNA fragment, which contains all VH domains of IgG2 and IgG3 isotypes followed by the second amplification VHH PCR with amplified fragments at 450 bp. The final PCR products were cloned into the phagemid vector pMECS then via phage display technique. Nano-antibodies protein was purified and separated under non-denaturing conditions by SDS-PAGE. The reactivity of each VHH of the selected clones was analyzed by Western blot assay. The isolated nano-antibodies showed binding not only to S. arizonae, but also to other bacterial strains, indicating that these nano-antibodies can be used in treatment but cannot use in diagnostic.

Peptide Controlled Shaping of Biomineralized Tin(II) Oxide into Flower-Like Particles

The size and morphology of metal oxide particles have a large impact on the physicochemical properties of these materials, e.g., the aspect ratio of particles affects their catalytic activity. Bioinspired synthesis routes give the opportunity to control precisely the structure and aspect ratio of the metal oxide particles by bioorganic molecules, such as peptides. This study focusses on the identification of tin(II) oxide (tin monoxide, SnO) binding peptides, and their effect on the synthesis of crystalline SnO microstructures. The phage display technique was used to identify the 7-mer peptide SnBP01 (LPPWKLK), which shows a high binding affinity towards crystalline SnO. It was found that the derivatives of the SnBP01 peptide, varying in peptide length and thus in their interaction, significantly affect the aspect ratio and the size dimension of mineralized SnO particles, resulting in flower-like morphology. Furthermore, the important role of the N-terminal leucine residue in the peptide for the strong organic–inorganic interaction was revealed by FTIR investigations. This bioinspired approach shows a facile procedure for the detailed investigation of peptide-to-metal oxide interactions, as well as an easy method for the controlled synthesis of tin(II) oxide particles with different morphologies.

Screening a specific Zn(ii)-binding peptide for improving the cognitive decline of Alzheimer's disease in APP/PS1 transgenic mice by inhibiting Zn2+-mediated amyloid protein aggregation and neurotoxicity

PZn screen from phage display technique and PZn loaded nanoparticles inhibiting Aβ aggregation and neurotoxicity in vitro and in vivo.