The TSP1-CD47-SIRPα interactome: an immune triangle for the checkpoint era

Area of Science:

• Immunology
• Oncology
• Molecular Biology

Background:

• Cancer immunotherapies targeting immune checkpoints (PD1, CTLA-4) have improved patient outcomes.
• Immune checkpoints are increasingly targeted by antibodies and engineered proteins.
• A broader perspective beyond immune inhibition is needed for checkpoint molecules.

Purpose of the Study:

• To explore the multifaceted roles of cell receptor CD47 beyond its known immune checkpoint function.
• To investigate how CD47 interacts with other molecules and pathways.
• To highlight the potential for novel therapeutic strategies based on CD47's complex signaling.

Main Methods:

• Review of existing literature on CD47 interactions and functions.
• Analysis of CD47's role in immune signaling (trans signal) and other cellular processes.
• Examination of CD47's interactions with thrombospondin-1 (TSP1) and SIRPα (cis signal).

Main Results:

• CD47 acts as an immune checkpoint by signaling through SIRPα on immune cells.
• CD47 also regulates redox signaling, metabolism, cell self-renewal, and blood flow.
• CD47 engages in both high-affinity (TSP1) and low-affinity (SIRPα) interactions, indicating convergent signaling.

Conclusions:

• CD47 possesses diverse functions beyond immune inhibition, impacting fundamental cellular processes.
• Understanding CD47's complex interactions reveals potential for pathway-specific cancer therapies.
• Targeting CD47 and its associated pathways may lead to more intelligent and effective therapeutic interventions.