👤 Shinsuke Sando

Fibroblast growth factor 2 (FGF2)regulates signal transduction by forming complexes with its receptors, FGF receptors (FGFRs), and heparan sulfate (HS), playing a crucial role in biological systems. Although HS has been suggested to modulate FGF/FGFR signaling as a coreceptor, multiple hypotheses exist regarding how HS affects FGF/FGFR signaling and the mechanism remains unclear. Herein, to highlight the role of FGF2/HS interaction in FGF2/FGFR1 signaling, FGF2 mutants with reduced HS-binding affinity are rationally designed through in silico analysis. These FGF2 mutants exhibit reduced HS affinity by more than two orders of magnitude while maintaining binding affinity to FGFR1. In addition, these mutants retain their thermal stability. Cellular assays using the FGF2 mutant suggest that, contrary to previous reports, the contribution of the FGF2/HS interaction in FGF2/FGFR1 signaling may be limited. The mutant FGFs that specifically alter the interaction with HS, achieved in this study, would contribute to an understanding of the role of FGF/HS interaction in FGF/FGFR signaling. Show less

DNA aptamers have attracted attention as an alternative modality for biomolecules due to their excellent target binding specificity and thermal stability, and they are also expected to be applied as artificial agonists for receptor proteins. DNA aptamer agonist TD0 targeting the receptor of fibroblast growth factor (FGFR), which plays an important role in the fields of wound healing and regenerative medicine, has been reported to induce cellular responses as well as its native ligands. However, it was also noted that there were some different responses upon long-term stimulation, suggesting that the intracellular signals induced by DNA aptamer agonist TD0 are different from those of natural ligands. In this paper, we comprehensively analyzed the intracellular signals induced by DNA aptamer agonist TD0 targeting FGFR1, and compared them with those by natural protein ligand FGF2. It was found that the intracellular signals were highly similar for short-term stimulation. On the other hand, the receptor and the downstream cellular signals showed different activation behaviors for long-time stimulation. Evaluating the stability and sustained activity of DNA aptamer agonist TD0 and FGF2 in the medium suggested that ligand stability may be important in properly regulating cellular responses. Show less