The role of exosomes in ankylosing spondylitis: from biological features and functional cargo to clinical applications.

Exosomes are small extracellular vesicles secreted by nearly all cell types and widely distributed in body fluids. They not only mediate intercellular material transfer but also play an important role in the regulation of immune pathways. Given their diverse biological functions, studies investigating the regulatory roles of exosomes in ankylosing spondylitis (AS) are receiving increasing attention. The functions of exosomes in AS largely depend on their bioactive cargo, including microRNAs (miRNAs), circular RNAs (circRNAs), long non-coding RNAs (lncRNAs), proteins, and other molecules. In addition, exosome-induced intercellular communication and modulation of immune regulatory pathways are also critical. Recent studies have shown that exosomal crosstalk mechanisms may affect major AS-related pathways, such as immune responses, inflammatory signaling, and bone metabolism balance. This review summarizes the biological characteristics of exosomes and advances in their functional cargos in AS regulation. More animal and clinical studies are needed to explore the role of exosomes in AS. The ongoing development of sequencing technologies and biotechnology indicates that exosomes hold potential as diagnostic biomarkers for AS and provide new insights into its diagnosis and treatment.