alarmin

Alarmin is a term used in immunology to describe endogenous molecules that are released from damaged or stressed cells and signal danger to the immune system. These molecules, often referred to as danger-associated molecular patterns (DAMPs), are not typically found outside of cells in healthy conditions. Their release acts as a warning signal, indicating tissue injury or infection, and initiating an inflammatory response to promote tissue repair or clear pathogens.

Common examples of alarmins include heat shock proteins, high-mobility group box 1 (HMGB1) protein, uric acid crystals, and adenosine triphosphate (ATP). These molecules bind to specific pattern recognition receptors (PRRs) on immune cells, such as Toll-like receptors (TLRs) and the inflammasome components. This binding triggers intracellular signaling pathways that lead to the production of pro-inflammatory cytokines and chemokines.

The function of alarmins is crucial for the initiation of adaptive immunity. By alerting immune cells to the presence of danger, alarmins help to bridge the innate and adaptive immune responses. This ensures that the immune system can effectively combat threats and restore tissue homeostasis. However, dysregulated alarmin release or signaling can contribute to chronic inflammatory diseases and autoimmune disorders. Research into alarmins continues to shed light on their complex roles in health and disease.