A Novel, Nonpeptidic, Orally Active Bivalent Inhibitor of Human β-Tryptase

Area of Science:

• Biochemistry
• Pharmacology
• Medicinal Chemistry

Background:

• Human tryptase is a homotetrameric serine protease implicated in allergic and inflammatory responses.
• Its structure, with four active sites, is amenable to bivalent inhibitor design.
• Attenuating tryptase activity presents a therapeutic challenge due to its elusive nature.

Purpose of the Study:

• To design and synthesize a novel bivalent inhibitor of human tryptase.
• To evaluate the pharmacological properties, including potency, bioavailability, and selectivity, of the novel inhibitor.
• To explore the therapeutic potential of targeting tryptase activity.

Main Methods:

• Synthesis of a novel bivalent tryptase inhibitor, compound 1a, utilizing a specific pharmacophoric core and disiloxane linker.
• In vitro enzymic and cellular screening assays to determine inhibitory activity (IC50) and off-rates.
• In vivo studies using HMC-1 xenograft models to assess oral bioavailability and efficacy.
• X-ray crystallography to validate the mechanism of inhibition.

Main Results:

• Compound 1a demonstrated superior inhibitory activity (IC50 = 1.82 nmol/L) compared to monomeric inhibitors.
• X-ray crystallography confirmed a dimeric mechanism of inhibition.
• Compound 1a exhibited good oral bioavailability, efficacy in xenograft models, slow off-rates, and high selectivity against related proteases.

Conclusions:

• Compound 1a is a highly potent, orally bioavailable, and selective non-peptide inhibitor of human tryptase.
• The bivalent inhibition strategy proved effective, yielding superior pharmacological properties.
• Compound 1a represents a valuable research tool for investigating the therapeutic potential of tryptase inhibition.