{"id":{"repo_id":"lancaster","oai_identifier":"oai:eprints.lancs.ac.uk:88763"},"canonical_url":"https://search.dev.ndltd.org/etd/lancaster/oai:eprints.lancs.ac.uk:88763","repository":{"repo_id":"lancaster","name":"Lancaster University","base_url":"https://eprints.lancs.ac.uk/cgi/oai2"},"display":{"title":"Developing peptide-based inhibitors of amylin aggregation as a novel treatment for type 2 diabetes","abstract":"Human islet amyloid polypeptide (hIAPP), also known as amylin, is the main constituent of the amyloid deposits present in approximately 95% of people with type 2 diabetes. Amylin aggregates into oligo-/polymeric sheet structures which are considered to be cytotoxic to pancreatic -cells. Inhibiting the early stages of amylin aggregation could provide a potential therapeutic strategy for the treatment of type 2 diabetes. In this study, overlapping peptides were designed to target the binding region (RLANFLVHSS, residues 11-20) of human amylin and their effects on amylin fibril formation were studied. The first generation of peptides, IO1, IO2, IO3, IO4, IO5, IO6 and IO7, showed less than 50% inhibition of amylin aggregation as observed using a Thioflavin T (Th-T) fluorescence assay. The next generation of peptides, IO8 and RI-IO8, were assessed using Th-T, Congo red and transmission electron microscopy (TEM) techniques. IO8 (H2N‑RGANFLVHGR-NH2) showed strong inhibitory effects on amylin aggregation, up to 71% inhibition, with TEM studies revealing a total inhibition of amylin fibril formation at a 1:1 molar ratio of peptide to amylin. MTS and LDH cytotoxicity studies revealed that IO8 protected human pancreatic islet β PANC-1 insulin producing cells from the toxic effects of human amylin. IO8 proved to be a significantly more potent inhibitor than the NMeG24 NMeI26 peptide reported in literature. In fact, contrary to reports in the literature, NMeG24 NMeI26 significantly enhanced amylin fibril formation. In addition, a homoarginine version of IO8, designed by replacing the arginine residues in IO8 (H2N-RGANFLVHGR-NH2) with homoarginine (H2N-HarGANFLVHGHar-NH2) also significantly impeded amylin fibril formation as observed by Th-T assay. To completely stabilise IO8 from proteolytic degradation, we designed RI-IO8 (Ac-rGhvlfnaGr-NH2), a retro-inverso peptide with L- replaced by D-amino acids. RI-IO8, however, significantly enhanced amylin fibril formation. Th-T experiments, Congo red assay and TEM revealed that two N-methylated versions of IO8, N1-IO8 (H2N-RGAmNFmLVmHGR-NH2) and N2-IO8 (H2N-RGANmFLmVHmR-NH2) significantly inhibited amylin aggregation by up to 85% and 87%, respectively, as observed by Th-T assay. TEM images revealed complete inhibition of fibril formation by N1-IO8 at a 1:1 molar ratio of peptide to amylin, and by N2-IO8 even at a 1:5 molar ratio of peptide to amylin. N1-IO8 and N2-IO8 were found to be stable against proteolytic enzymes, and in plasma, unlike IO8, and also protected human pancreatic islet β PANC-1 cells from the toxic effects of human amylin, and were themselves non-toxic to cells. These studies show that these N-methylated peptides, N1-IO8 and N2-IO8, are potent inhibitors of amylin aggregation and could be developed as a novel treatment for type 2 diabetes.","abstract_html":"Human islet amyloid polypeptide (hIAPP), also known as amylin, is the main constituent of the amyloid deposits present in approximately 95% of people with type 2 diabetes. Amylin aggregates into oligo-/polymeric sheet structures which are considered to be cytotoxic to pancreatic -cells. Inhibiting the early stages of amylin aggregation could provide a potential therapeutic strategy for the treatment of type 2 diabetes. In this study, overlapping peptides were designed to target the binding region (RLANFLVHSS, residues 11-20) of human amylin and their effects on amylin fibril formation were studied. The first generation of peptides, IO1, IO2, IO3, IO4, IO5, IO6 and IO7, showed less than 50% inhibition of amylin aggregation as observed using a Thioflavin T (Th-T) fluorescence assay. The next generation of peptides, IO8 and RI-IO8, were assessed using Th-T, Congo red and transmission electron microscopy (TEM) techniques. IO8 (H2N‑RGANFLVHGR-NH2) showed strong inhibitory effects on amylin aggregation, up to 71% inhibition, with TEM studies revealing a total inhibition of amylin fibril formation at a 1:1 molar ratio of peptide to amylin. MTS and LDH cytotoxicity studies revealed that IO8 protected human pancreatic islet β PANC-1 insulin producing cells from the toxic effects of human amylin. IO8 proved to be a significantly more potent inhibitor than the NMeG24 NMeI26 peptide reported in literature. In fact, contrary to reports in the literature, NMeG24 NMeI26 significantly enhanced amylin fibril formation. In addition, a homoarginine version of IO8, designed by replacing the arginine residues in IO8 (H2N-RGANFLVHGR-NH2) with homoarginine (H2N-HarGANFLVHGHar-NH2) also significantly impeded amylin fibril formation as observed by Th-T assay. To completely stabilise IO8 from proteolytic degradation, we designed RI-IO8 (Ac-rGhvlfnaGr-NH2), a retro-inverso peptide with L- replaced by D-amino acids. RI-IO8, however, significantly enhanced amylin fibril formation. Th-T experiments, Congo red assay and TEM revealed that two N-methylated versions of IO8, N1-IO8 (H2N-RGAmNFmLVmHGR-NH2) and N2-IO8 (H2N-RGANmFLmVHmR-NH2) significantly inhibited amylin aggregation by up to 85% and 87%, respectively, as observed by Th-T assay. TEM images revealed complete inhibition of fibril formation by N1-IO8 at a 1:1 molar ratio of peptide to amylin, and by N2-IO8 even at a 1:5 molar ratio of peptide to amylin. N1-IO8 and N2-IO8 were found to be stable against proteolytic enzymes, and in plasma, unlike IO8, and also protected human pancreatic islet β PANC-1 cells from the toxic effects of human amylin, and were themselves non-toxic to cells. These studies show that these N-methylated peptides, N1-IO8 and N2-IO8, are potent inhibitors of amylin aggregation and could be developed as a novel treatment for type 2 diabetes.","abstract_has_math":false,"creators":["Obasse, Idira Christopher","Allsop, David","Parkin, Edward"],"institution":"Lancaster University","degree_name":"Ph.D.","degree_level":"doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2017,"date_issued":"2017","date_published":"2017","updated_at":"2026-07-24T02:48:37Z","subjects":[],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Obasse, Idira Christopher","Allsop, David","Parkin, Edward"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2017"]},{"key":"dc:date.issued","label":"Date","values":["2017"]},{"key":"dc:publisher.commercial","label":"Dc Publisher Commercial","values":["Lancaster University"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Biomedical & Life Sciences"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["Lancaster University"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://eprints.lancs.ac.uk/id/eprint/88763/"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["Ph.D."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://eprints.lancs.ac.uk/id/eprint/88763/1/2017ObassePhD.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Human islet amyloid polypeptide (hIAPP), also known as amylin, is the main constituent of the amyloid deposits present in approximately 95% of people with type 2 diabetes. Amylin aggregates into oligo-/polymeric sheet structures which are considered to be cytotoxic to pancreatic -cells. Inhibiting the early stages of amylin aggregation could provide a potential therapeutic strategy for the treatment of type 2 diabetes. In this study, overlapping peptides were designed to target the binding region (RLANFLVHSS, residues 11-20) of human amylin and their effects on amylin fibril formation were studied. The first generation of peptides, IO1, IO2, IO3, IO4, IO5, IO6 and IO7, showed less than 50% inhibition of amylin aggregation as observed using a Thioflavin T (Th-T) fluorescence assay. The next generation of peptides, IO8 and RI-IO8, were assessed using Th-T, Congo red and transmission electron microscopy (TEM) techniques. IO8 (H2N‑RGANFLVHGR-NH2) showed strong inhibitory effects on amylin aggregation, up to 71% inhibition, with TEM studies revealing a total inhibition of amylin fibril formation at a 1:1 molar ratio of peptide to amylin. MTS and LDH cytotoxicity studies revealed that IO8 protected human pancreatic islet β PANC-1 insulin producing cells from the toxic effects of human amylin. IO8 proved to be a significantly more potent inhibitor than the NMeG24 NMeI26 peptide reported in literature. In fact, contrary to reports in the literature, NMeG24 NMeI26 significantly enhanced amylin fibril formation. In addition, a homoarginine version of IO8, designed by replacing the arginine residues in IO8 (H2N-RGANFLVHGR-NH2) with homoarginine (H2N-HarGANFLVHGHar-NH2) also significantly impeded amylin fibril formation as observed by Th-T assay. To completely stabilise IO8 from proteolytic degradation, we designed RI-IO8 (Ac-rGhvlfnaGr-NH2), a retro-inverso peptide with L- replaced by D-amino acids. RI-IO8, however, significantly enhanced amylin fibril formation. Th-T experiments, Congo red assay and TEM revealed that two N-methylated versions of IO8, N1-IO8 (H2N-RGAmNFmLVmHGR-NH2) and N2-IO8 (H2N-RGANmFLmVHmR-NH2) significantly inhibited amylin aggregation by up to 85% and 87%, respectively, as observed by Th-T assay. TEM images revealed complete inhibition of fibril formation by N1-IO8 at a 1:1 molar ratio of peptide to amylin, and by N2-IO8 even at a 1:5 molar ratio of peptide to amylin. N1-IO8 and N2-IO8 were found to be stable against proteolytic enzymes, and in plasma, unlike IO8, and also protected human pancreatic islet β PANC-1 cells from the toxic effects of human amylin, and were themselves non-toxic to cells. These studies show that these N-methylated peptides, N1-IO8 and N2-IO8, are potent inhibitors of amylin aggregation and could be developed as a novel treatment for type 2 diabetes."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Developing peptide-based inhibitors of amylin aggregation as a novel treatment for type 2 diabetes"]}]}],"canonical_facts":{"dc:creator":["Obasse, Idira Christopher","Allsop, David","Parkin, Edward"],"dc:date":["2017"],"dc:date.issued":["2017"],"dc:description.abstract":["Human islet amyloid polypeptide (hIAPP), also known as amylin, is the main constituent of the amyloid deposits present in approximately 95% of people with type 2 diabetes. Amylin aggregates into oligo-/polymeric sheet structures which are considered to be cytotoxic to pancreatic -cells. Inhibiting the early stages of amylin aggregation could provide a potential therapeutic strategy for the treatment of type 2 diabetes. In this study, overlapping peptides were designed to target the binding region (RLANFLVHSS, residues 11-20) of human amylin and their effects on amylin fibril formation were studied. The first generation of peptides, IO1, IO2, IO3, IO4, IO5, IO6 and IO7, showed less than 50% inhibition of amylin aggregation as observed using a Thioflavin T (Th-T) fluorescence assay. The next generation of peptides, IO8 and RI-IO8, were assessed using Th-T, Congo red and transmission electron microscopy (TEM) techniques. IO8 (H2N‑RGANFLVHGR-NH2) showed strong inhibitory effects on amylin aggregation, up to 71% inhibition, with TEM studies revealing a total inhibition of amylin fibril formation at a 1:1 molar ratio of peptide to amylin. MTS and LDH cytotoxicity studies revealed that IO8 protected human pancreatic islet β PANC-1 insulin producing cells from the toxic effects of human amylin. IO8 proved to be a significantly more potent inhibitor than the NMeG24 NMeI26 peptide reported in literature. In fact, contrary to reports in the literature, NMeG24 NMeI26 significantly enhanced amylin fibril formation. In addition, a homoarginine version of IO8, designed by replacing the arginine residues in IO8 (H2N-RGANFLVHGR-NH2) with homoarginine (H2N-HarGANFLVHGHar-NH2) also significantly impeded amylin fibril formation as observed by Th-T assay. To completely stabilise IO8 from proteolytic degradation, we designed RI-IO8 (Ac-rGhvlfnaGr-NH2), a retro-inverso peptide with L- replaced by D-amino acids. RI-IO8, however, significantly enhanced amylin fibril formation. Th-T experiments, Congo red assay and TEM revealed that two N-methylated versions of IO8, N1-IO8 (H2N-RGAmNFmLVmHGR-NH2) and N2-IO8 (H2N-RGANmFLmVHmR-NH2) significantly inhibited amylin aggregation by up to 85% and 87%, respectively, as observed by Th-T assay. TEM images revealed complete inhibition of fibril formation by N1-IO8 at a 1:1 molar ratio of peptide to amylin, and by N2-IO8 even at a 1:5 molar ratio of peptide to amylin. N1-IO8 and N2-IO8 were found to be stable against proteolytic enzymes, and in plasma, unlike IO8, and also protected human pancreatic islet β PANC-1 cells from the toxic effects of human amylin, and were themselves non-toxic to cells. These studies show that these N-methylated peptides, N1-IO8 and N2-IO8, are potent inhibitors of amylin aggregation and could be developed as a novel treatment for type 2 diabetes."],"dc:format":["application/pdf"],"dc:identifier.uri":["https://eprints.lancs.ac.uk/id/eprint/88763/1/2017ObassePhD.pdf"],"dc:publisher.commercial":["Lancaster University"],"dc:publisher.department":["Biomedical & Life Sciences"],"dc:publisher.institution":["Lancaster University"],"dc:relation.isreferencedby":["https://eprints.lancs.ac.uk/id/eprint/88763/"],"dc:title":["Developing peptide-based inhibitors of amylin aggregation as a novel treatment for type 2 diabetes"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["doctoral"],"dc:type.qualificationname":["Ph.D."]},"updated_at":"2026-07-24T02:48:37Z"}