Le Gall, L. | Search bioRxiv

bioRxiv2024

Extracellular RNA induce neutrophil recruitment via endothelial TLR3 during venous thrombosis after vascular injury

BackgroundVenous thromboembolism is associated with endothelial cell activation that contributes to the inflammation-dependent activation of the coagulation system. Cellular damages are associated with the release of different species of extracellular RNA (eRNA) involved in inflammation and coagulation. TLR3, which recognizes (viral) double-stranded RNA, single-stranded RNA, and also self-RNA fragments might be the receptor of these eRNA during venous thromboembolism. We investigate how eRNA regulate endothelial function through TLR3 and contribute to venous thromboembolism. Methods and ResultsThrombus formation and size in WT and TLR3 deficient (-/-) mice were monitored by ultrasonography after venous thrombosis using the FeCl3 and stasis models. Mice were treated with RNase1, poly(I:C) or RNA extracted from murine endothelial cells (eRNA). Gene expression and signaling pathway activation were analyzed in HEK293T cells overexpressing TLR3 in response to eRNA or in HUVECs transfected with a siRNA against TLR3. Plasma clot formation on treated HUVECs was analyzed. Thrombosis exacerbated RNA release in vivo and increased RNA content within the thrombus. RNase1 treatment reduced thrombus size compared to vehicle-treated mice. Poly(I:C) and eRNA treatments increased thrombus size in WT mice, but not in TLR3-/- mice, by bolstering neutrophil recruitment. Mechanistically, TLR3 activation in endothelial cells promotes CXCL5 secretion and neutrophil recruitment in vitro. eRNA triggered plasma clot formation. eRNA mediate these effects through TLR3-dependent activation of NF{kappa}B. ConclusionsWe show that eRNA and TLR3 activation enhance venous thromboembolism through neutrophil recruitment and secretion of CXCL5.

physiology↗

bioRxiv2023

Non-indigenous seaweeds in the Northeast Atlantic Ocean, the Mediterranean Sea and Macaronesia: a critical synthesis of diversity, spatial and temporal patterns

Effective monitoring and combatting the effect of non-indigenous seaweeds relies on a solid confirmation of the non-indigenous status of the species. We critically analysed the status of presumed non-indigenous seaweed species reported from the Mediterranean Sea, the Northeast Atlantic Ocean and Macaronesia, resulting in a list of 140 species whose non-indigenous nature is undisputed. For an additional 87 species it is unclear if they are native or non-indigenous (cryptogenic species) or their identity requires confirmation (data deficient species). We discuss the factors underlying both taxonomic and biogeographic uncertainties and outline recommendations to reduce uncertainty about the non-indigenous status of seaweeds. Our dataset consisted of over 19,000 distribution records, half of which can be attributed to only five species (Sargassum muticum, Bonnemaisonia hamifera, Asparagopsis armata, Caulerpa cylindracea and Colpomenia peregrina), while 56 species (40%) are recorded no more than once or twice. In addition, our analyses revealed considerable variation in the diversity of non-indigenous species between the geographic regions. The Eastern Mediterranean Sea is home to the largest fraction of non-indigenous seaweed species, the majority of which have a Red Sea or Indo-Pacific origin and have entered the Mediterranean Sea mostly via the Suez Canal. Non-indigenous seaweeds with native ranges situated in the Northwest Pacific make up a large fraction of the total in the Western Mediterranean Sea, Lusitania and Northern Europe, followed by non-indigenous species with a presumed Australasian origin. Uncertainty remains, however, regarding the native range of a substantial fraction of non-indigenous seaweeds in the study area. In so far as analyses of first detections can serve as a proxy for the introduction rate of non-indigenous seaweeds, these do not reveal a decrease in the introduction rate, indicating that the current measures and policies are insufficient to battle the introduction and spread of non-indigenous species in the study area. HighlightsO_LINon-indigenous seaweed species in the Northeast Atlantic Ocean, the Mediterranean Sea and Macaronesia are critically reanalysed. C_LIO_LI>19,000 distribution records revealed considerable variation in diversity of non-indigenous seaweed species in the study area. C_LIO_LITaxonomic and biogeographic uncertainties hamper a critical evaluation of the non-indigenous status of many seaweed species. C_LI

plant biology↗