Allosteric targeting resolves limitations of earlier LFA-1 directed modalities

Area of Science:

• Immunology
• Pharmacology
• Biochemistry

Background:

• Integrins are crucial cell surface receptors with therapeutic potential, but their targeting is complicated by unforeseen downstream signaling effects.
• Lymphocyte function-associated antigen-1 (LFA-1) is a key integrin target, often affected by these complex signaling interactions.
• Previous LFA-1 inhibitors, including ligand mimetics and antibodies, have faced challenges with partial agonism and off-target effects.

Purpose of the Study:

• To identify and characterize a novel class of allosteric small molecule inhibitors for LFA-1.
• To overcome the limitations of previous LFA-1 targeting strategies, such as partial agonism and unintended cross-reactivity.
• To establish a new generation of LFA-1 inhibitors with a favorable preclinical profile for immune-regulatory applications.

Main Methods:

• A two-tiered, ligand-based virtual screening approach was employed to discover new chemical scaffolds targeting the LFA-1 αI domain.
• The identified scaffold was derivatized to create potent bis- and tris-aryl-bicyclic-succinimides.
• Extensive in vitro characterization assessed inhibition potency, selectivity, agonism, internalization effects, and oral availability compared to existing LFA-1 inhibitors.

Main Results:

• Novel allosteric small molecule inhibitors targeting LFA-1 were identified, exhibiting low nanomolar inhibitory concentrations in vitro.
• These new inhibitors demonstrated a lack of partial agonism, selective binding to LFA-1 over other integrins, and did not induce LFA-1 internalization.
• The compounds displayed favorable oral availability, differentiating them from earlier LFA-1 targeting agents.

Conclusions:

• A new class of allosteric LFA-1 inhibitors with a distinct and advantageous preclinical profile has been developed.
• These inhibitors offer a promising foundation for novel immune regulatory therapies targeting LFA-1 selectively.
• The computational and experimental framework used is adaptable for the discovery and development of other allosteric integrin inhibitors.