In vivo phage display: identification of organ-specific peptides using deep sequencing and differential profiling across tissues.
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ABSTRACT:
SUBMITTER: Pleiko K
PROVIDER: S-EPMC8053097 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Therapies selectively targeting ischemic myocardium could be applied by intravenous injection. Here, we report an approach for ischemic tissue-selective targeting based on in vivo screening of random peptide sequences using phage display. We performed in vivo biopanning using a phage library in a rat model of ischemia-reperfusion and identified three peptide motifs, CSTSMLKAC, CKPGTSSYC, and CPDRSVNNC, that exhibited preferential binding to ischemic heart tissue compared to normal heart as well as other control organs. The CSTSMLKAC sequence was capable of mediating selective homing of phage to ischemic heart tissue. The CSTSMLKAC peptide was then made as a fusion protein with Sumo-mCherry and injected intravenously in a mouse model of myocardial ischemia-reperfusion injury; subsequently, bio-distribution of Sumo-mCherry-CSTSMLKAC was measured with quantitative ELISA. The targeting peptide led to a significant increase in homing to ischemic left ventricle compared to tissues from non-ischemic left ventricle, the right ventricle, lung, liver, spleen, skeletal muscle, and brain (all p<0.001). These results indicate that the peptide sequence CSTSMLKAC represents a novel molecular tool that may be useful in targeting ischemic tissue and delivering bioengineered proteins into the injured myocardium by systemic intravenous administration.
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Project description:PURPOSE:Osteosarcoma represents the most common malignant primary bone tumor in childhood; however, the survival rate has remained unchanged for the past 20 years. To improve existing diagnosis and treatment methods and broaden the spectrum of imaging agents that can be used for early detection and assessment of tumor response to therapy, we performed a phage display-based screening for peptide sequences that bind specifically to osteosarcoma cells. EXPERIMENTAL DESIGN:From the Ph.D.-12 phage display peptide library composed of 2.7 x 10(9) different displayed peptides, one peptide was enriched after four rounds of in vitro selection in 143B osteosarcoma tumor cells with 293T human embryonic kidney cells as a control. Both the peptide and the phage clone displaying the peptide were conjugated with fluorescent dyes for in vitro cell and ex vivo tumor tissue stainings. The peptide was further labeled with (18)F for positron emission tomography imaging studies. Cell uptake and efflux and ex vivo biodistribution were also done with (18)F-labeled osteosarcoma specific peptide. RESULTS:ASGALSPSRLDT was the dominant sequence isolated from biopanning and named as OSP-1. OSP-1 shares a significant homology with heparinase II/III family protein, which binds and reacts with heparan sulfate proteoglycans. The fluorescence staining showed that FITC-OSP-1-phage or Cy5.5-OSP-1 had high binding with a panel of osteosarcoma cell lines, much less binding with UM-SCC1 human head and neck squamous cell carcinoma cells, and almost no binding with 293T cells, whereas the scrambled peptide OSP-S had virtually no binding to all the cell lines. (18)F-OSP-1 had significantly higher accumulation in 143B tumor cells both in vitro and in vivo than (18)F-OSP-S. (18)F-OSP-1 also had higher uptake in 143B tumors than in UM-SCC-1 tumors. CONCLUSIONS:Our data suggest that OSP-1 peptide is osteosarcoma specific, and the binding site of OSP-1 might be related to heparan sulfate proteoglycans. Appropriately labeled OSP-1 peptide has the potential to serve as a novel probe for osteosarcoma imaging.
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Project description:Coeliac disease (CD) is a common and complex disorder of the small intestine caused by intolerance to wheat gluten and related edible cereals like barley and rye. Peptides originating from incomplete gliadin digestion activate the lamina propria infiltrating T cells to release proinflammatory cytokines, which in turn cause profound tissue remodelling of the small intestinal wall. There is no cure for CD except refraining from consuming gluten-containing products.Phage from a random oligomer display library were enriched by repeated pannings against immobilised gliadin proteins. Phage from the final panning round were plated, individual plaques picked, incubated with host bacteria, amplified to a population size of 1011 to 1012 and purified. DNA was isolated from 1000 purified phage populations and the region covering the 36 bp oligonucleotide insert from which the displayed peptides were translated, was sequenced. Altogether more than 150 different peptide-encoding sequences were identified, many of which were repeatedly isolated under various experimental conditions. Amplified phage populations, each expressing a single peptide, were tested first in pools and then one by one for their ability to inhibit binding of human anti-gliadin antibodies in ELISA assays. These experiments showed that several of the different peptide-expressing phage tested inhibited the interaction between gliadin and anti-gliadin antibodies. Finally, four different peptide-encoding sequences were selected for further analysis, and the corresponding 12-mer peptides were synthesised in vitro. By ELISA assays it was demonstrated that several of the peptides inhibited the interaction between gliadin molecules and serum anti-gliadin antibodies. Moreover, ELISA competition experiments as well as dot-blot and western blot revealed that the different peptides interacted with different molecular sites of gliadin.We believe that several of the isolated and characterised gliadin-binding peptides described here could provide valuable tools for researchers in the field of CD by facilitating studies on localisation and uptake of various gliadin peptides in the small intestine. In future work, the potential of these peptides to detoxify gluten will be investigated.
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