McLaughlin, J. | Search bioRxiv

bioRxiv2019

Isolation and characterisation of watermelon (Citrullus lanatus) extracellular vesicles and their cargo

Extracellular vesicles (EVs) facilitate cell-cell communication in animals and are integral to many physiological and pathological processes. Evidence for the presence and function of EVs in plants is limited. Here, we report that EVs derived from watermelon fruit mesocarp are of similar size and morphology to the animal EV subtype known as exosomes. Analysis of EV constituents revealed that watermelon EVs are negative for endoplasmic reticulum markers, and that the miRNA and protein profiles differ from that of watermelon mesocarp cells, suggesting that these EVs are actively synthesised and are not merely cellular debris. Furthermore, we report a panel of proteins found in in watermelon EVs as well as the published proteomes of grape, grapefruit, lemon and Arabidopsis thaliana EVs that are novel potential plant EV markers. Bioinformatic analyses suggest that plastids and multivesicular bodies are likely sites of biogenesis for EVs from watermelon and other plants. Predicted functional roles of watermelon EVs include development and metabolism, with several of their cargo molecules likely to be key in regulation of fruit development and ripening. Further understanding of how EVs may contribute to these processes would improve understanding of plant cell-cell communication and could aid in the harnessing of plant EVs for greater temporal control of crop development/ripening for the agricultural and retail industries.

plant biology↗

bioRxiv2019

Differential expression of soluble receptor for advanced glycation end-products (sRAGE) in mice susceptible or resistant to chronic colitis

AimsIdentifying the factors that contribute to chronicity in inflamed colitic tissue is not trivial. However, in mouse models of colitis, we can investigate at preclinical timepoints. We sought to validate murine Trichuris muris infection as a model for identification of factors that promote development of chronic colitis.\n\nMethodsWe compared preclinical changes in mice with a resolving immune response to T. muris (resistant) versus mice that fail to expel the worms and develop chronic colitis (susceptible). Findings were then validated in healthy controls and patients with suspected or confirmed IBD.\n\nResultsThe Receptor for Advanced Glycation End Products (Rage) was highly dysregulated between resistant and susceptible mice prior to the onset of any pathological signs. Increased soluble RAGE (sRAGE) in the serum and faeces of resistant mice correlated with reduced colitis scores. Mouse model findings were validated in a preliminary clinical study: faecal sRAGE was differentially expressed in patients with active IBD compared with IBD in remission, patients with IBD excluded or healthy controls.\n\nConclusionPre-clinical changes in mouse models can identify early pathways in the development of chronic inflammation that human studies cannot. We identified the decoy receptor sRAGE as a potential mechanism for protection against chronic inflammation in colitis in mice and humans. We propose that the RAGE pathway is clinically relevant in the onset of chronic colitis, and that further study of sRAGE in IBD may provide a novel diagnostic and therapeutic target.

immunology↗