Substrates, Cofactors, and Cellular Targets of Coagulation Factor XIa

Area of Science:

• Biochemistry
• Hematology
• Immunology

Background:

• Coagulation factor XI (FXI) is a zymogen activated to FXIa, playing a role in the coagulation cascade.
• FXI's evolutionary origins are linked to plasma prekallikrein, with subsequent divergence leading to its unique function in hemostasis.
• FXIa is known for activating factor IX but also contributes to thrombin generation independently.

Purpose of the Study:

• To critically review the current knowledge on FXI's role in hemostasis, inflammation, and immune responses.
• To highlight future research directions for understanding FXI's physiological and pathological functions.
• To emphasize the importance of FXI as a druggable target in clinical exploration.

Main Methods:

• Literature review of existing research on Coagulation factor XI.
• Analysis of FXI's interactions with platelets, endothelial cells, and inflammatory pathways.
• Evaluation of FXI's role in activating factor IX and generating bradykinin.

Main Results:

• FXI is involved in both the intrinsic pathway of coagulation and thrombin generation independent of factor IX.
• FXI interacts with platelets and endothelial cells, influencing hemostasis.
• FXI mediates inflammatory responses via activation of FXII and bradykinin generation.

Conclusions:

• FXI plays a complex, multifaceted role integrating hemostasis, inflammation, and immunity.
• Further research is needed to fully elucidate FXI's mechanisms in health and disease.
• Understanding FXI is critical as it emerges as a significant therapeutic target.