A novel series of potent and selective small molecule inhibitors of the complement component C1s

Area of Science:

• Biochemistry
• Immunology
• Medicinal Chemistry

Background:

• The classical complement pathway is implicated in diseases like hereditary angioedema and transplant rejection.
• The serine protease C1s is a key upstream regulator of this pathway.
• C1s represents a promising therapeutic target for controlling complement activation.

Purpose of the Study:

• To develop and optimize novel inhibitors targeting the C1s enzyme.
• To evaluate the efficacy of these inhibitors in blocking the classical complement pathway.

Main Methods:

• Design and synthesis of thiopheneamidine-based compounds.
• Optimization of inhibitor potency.
• In vitro assays to assess inhibition of the classical complement pathway.

Main Results:

• A potent thiopheneamidine-based inhibitor of C1s was successfully optimized.
• The lead inhibitor demonstrated significant inhibition of the classical complement pathway in vitro.
• Achieved an inhibitor concentration of 70 nM.

Conclusions:

• Thiopheneamidine derivatives are effective inhibitors of C1s.
• Targeting C1s offers a viable therapeutic approach for complement-mediated diseases.
• Further development of these inhibitors may lead to new treatments.