Acute joint inflammation induces a sharp increase in the number of synovial fluid EVs and modifies their phospholipid profile

• Published in: Biochimica et biophysica acta. Molecular and cell biology of lipids Vol. 1868; no. 10; p. 159367
• Main Authors: Varela, Laura, van de Lest, Chris H.A., Boere, Janneke, Libregts, Sten F.W.M., Lozano-Andrés, Estefanía, van Weeren, P. René, Wauben, Marca H.M.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-10-2023
• Subjects: Equine; Extracellular vesicles; Inflammation; Joint; Lipidomics; Synovial fluid; Synovitis; PE O; Synovitis; PS; Extracellular vesicles; Lipidomics; Inflammation; Joint; EV; Synovial fluid; SF; PC; PE; HexCer; SF-EV; SM; Equine
• ISSN: 1388-1981; 1879-2618
• DOI: 10.1016/j.bbalip.2023.159367

Inflammation is the hallmark of most joint disorders. However, the precise regulation of induction, perpetuation, and resolution of joint inflammation is not entirely understood. Since extracellular vesicles (EVs) are critical for intercellular communication, we aim to unveil their role in these processes. Here, we investigated the EVs' dynamics and phospholipidome profile from synovial fluid (SF) of healthy equine joints and from horses with lipopolysaccharide (LPS)-induced synovitis.
LPS injection triggered a sharp increase of SF-EVs at 5-8 h post-injection, which started to decline at 24 h post-injection. Importantly, we identified significant changes in the lipid profile of SF-EVs after synovitis induction. Compared to healthy joint-derived SF-EVs (0 h), SF-EVs collected at 5, 24, and 48 h post-LPS injection were strongly increased in hexosylceramides. At the same time, phosphatidylserine, phosphatidylcholine, and sphingomyelin were decreased in SF-EVs at 5 h and 24 h post-LPS injection. Based on the lipid changes during acute inflammation, we composed specific lipid profiles associated with healthy and inflammatory state-derived SF-EVs. The sharp increase in SF-EVs during acute synovitis and the correlation of specific lipids with either healthy or inflamed states-derived SF-EVs are findings of potential interest for unveiling the role of SF-EVs in joint inflammation, as well as for the identification of EV-biomarkers of joint inflammation.
•Acute joint inflammation induces a rapid increase in the number of synovial fluid extracellular vesicles•Induced synovitis results in changes of the phospholipid composition of synovial fluid-derived extracellular vesicles•The phospholipidome profile of extracellular vesicles is dynamic•Extracellular vesicles in healthy and inflammatory state synovial fluid have distinct phospholipid profiles