PDGF mutants and methods of use thereof

Inventors

Imoukhuede, Princess • Procko, Erik

Assignees

University of Washington • Washington University in St. Louis • University of Illinois System

Abstract

Isolated polypeptides having enhanced affinity for a PDGF receptor and/or a VEGF receptor are provided. Compositions comprising the polypeptides and methods of use thereof are also provided.

Core Innovation

The patent describes isolated polypeptide mutants derived from PDGF-B and related PDGF polypeptides that bind to PDGF receptors and/or VEGF receptors and increase PDGF and/or VEGF signaling in the cell. The polypeptides are defined by amino acid sequence identity relative to SEQ ID NO: 1 and by specific amino acid substitutions that result in higher binding affinity to the receptor than a wild-type PDGF or VEGF polypeptide. The sequence substitutions include M12R, I13E, K17N, E21Y, V22L, E24R, R28N, R32I, N57Y, Q71M, and T101K, with conservative or additional substitutions selected from 177F and K98R.

The disclosure further includes polypeptides having amino acid sequences comprising any one of SEQ ID NOs: 2-9 and 11, and describes variants that are dimer-forming, including PDGF-B dimers and heterodimers or homodimers. The core concept is to create receptor-interface mutations that produce increased cross-family binding between PDGF and VEGF receptors, with the polypeptides increasing PDGF and/or VEGF signaling in the cell. The receptors explicitly include PDGFRα and PDGFRβ as well as VEGF receptors such as VEGFR2.

As described in the patent summary, the problem being solved is the need to modulate PDGF/VEGF signaling by using receptor-binding polypeptides with increased receptor affinity compared with wild-type PDGF or VEGF polypeptides. The document supports this concept with characterization and analysis of mutant receptor binding and signaling, including identification of receptor-interface mutations, and a systems biology and simulation basis for PDGF→VEGFR2 cross-signaling. Functional readouts described include assays for cell signaling and wound-healing performance, together with signaling characterization involving PDGFR phosphorylation.

Claims Coverage

The patent includes two independent claims, clm-00001 and clm-00013, both directed to isolated polypeptides that bind PDGF receptors and/or VEGF receptors and increase PDGF and/or VEGF signaling. Across these claims, the inventive focus is on receptor binding with increased affinity via specified substitutions or specified SEQ ID NOs, and the resulting increase in signaling in the cell; additional dependent claims expand to formulations, nucleic acids, vectors, host cells, and treatment use where PDGF/VEGF signaling is insufficient or reduced.

Overall, claim coverage centers on isolated polypeptides that bind PDGF and/or VEGF receptors and increase PDGF and/or VEGF signaling in cells, with specificity provided either by higher-affinity amino acid substitutions relative to SEQ ID NO: 1 or by restricting the polypeptide to particular SEQ ID NOs.

Stated Advantages

Documented Applications