IDDF2024-ABS-0118 Preliminary study on houttuynia cordata-derived exosome-like nanovesicles ameliorating experimental colitis

<h3>Background</h3> Plant-derived exosome-like nanoparticles (PELNs) have been considered to have great prospects in the treatment of ulcerative colitis (UC) as they serve as a natural nano-drug carrier that can improve drug stability and cellular uptake. In this study, we isolated Houttuynia cordata-derived exosome-like nanoparticles (HELNs) from Houttuynia cordata and preliminarily explored the protective effect of HELNs on sodium dextran sulfate (DSS) induced colitis model. <h3>Methods</h3> HELNs were isolated from Houttuynia cordata using sucrose density gradient centrifugation.18 BALB/c mice were randomly divided into Ctrl (regular water), DSS (3.0% DSS water), and DSS+HELNs (DSS water + HELNs) groups. The mice were monitored daily for their body weights, stool consistency, and the presence of blood in the anus or stool. At the end of the experiment, their colon tissue was dissected. The colon lengths were measured, and the dissected tissues were collected for qPCR and pathology. <h3>Results</h3> After HELNs intervention, diarrhea, bloody stool and weight loss in colitis mice were alleviated (p&lt;0.01). Disease activity index (DAI) score (p=0.0229) decreased, and colon length (p&lt;0.01) improved. Compared with the DSS group, the pathological damage to the colon in the DSS+HELNs group was milder, which was mainly manifested by intact colonic mucosal structure and crypt structure, less inflammatory cell infiltration, and more goblet cells. Compared with the DSS group, the relative mRNA expression of pro-inflammatory cytokines (TNF-α and IL-6) was decreased (p&lt;0.0001; p&lt;0.0001), the relative expression level of anti-inflammatory cytokine IL-10 increased (p=0.0386), while the expression of tight junction protein of occlusion band protein-1 (ZO-1), occlusin-1 and mucin-2 (MUC2) increased (p=0.0341; p=0.0267). (IDDF2024-ABS-0118 Figure 1. Oral administration of HELNs protects mice from DSS-induced colitis, IDDF2024-ABS-0118 Figure 2. Transmission electron microscopy (TEM) images of HELNs and characterization of HELNs.; p&lt;0.0001) <h3>Conclusions</h3> We first explored the use of HELNs in experimental colitis and found that HELNs play a therapeutic role by reducing the expression of inflammatory cytokines and promoting the restoration of intestinal barrier function.