Analysis of Islet Exosomal miRNAs Released Post-Transplant in Response to Inflammation

P. Saravanan¹, M. Kanak¹, G. Yoshimatsu², C. Darden², M. Lawrence², M. Levy¹, B. Naziruddin³

¹Department of Surgery, Virginia Commonwealth University, VCU Health, Richmond, VA, ²Islet Cell Lab, Baylor Scott and White Research Institute, Dallas, TX, ³Simmons Transplant Institute, Baylor Scott and White Research Center, Dallas, TX

Meeting: 2019 American Transplant Congress

Abstract number: A118

Keywords: Graft function, Inflammation, Islets, Nuclear factor-kappa B (NF-kB)

Session Information

Session Name: Poster Session A: Islet Cell and Cell Transplantation

Session Type: Poster Session

Date: Saturday, June 1, 2019

Session Time: 5:30pm-7:30pm

Presentation Time: 5:30pm-7:30pm

Location: Hall C & D

*Purpose: Islets release miRNAs and other non-coding RNAs via exosomes under various pathological conditions, which are capable of regulating the genes of neighboring and/or distant cells. Inflammatory conditions occurring immediately post-transplantation may also result in release of exosomes by islets that may modulate gene expression profile of neighboring islets and immune cells. In this study, we analyzed the exosomal miRNAs released after islet transplantation and determined their possible targets using KEGG analysis and validated using mirTRAP based in vitro testing.

*Methods: Human islets were exposed to inflammatory conditions in vitro and exosomal miRNA sequencing was performed. Streptozotocin induced diabetic mice were transplanted with human islets under kidney capsule (n=5). After 24hrs post-transplantation exosomes were extracted from the plasma using miRCURY exosome isolation kit. LNA based qPCR assay was performed on 10 miRNAs selected from miRNA sequencing data. KEGG analysis was performed on stress related miRNAs, which was further validated using human islet cell based mirTRAP experiments.

*Results: Based on exo-miRNA sequencing data, 10 miRNAs that were highly upregulated in response to inflammation were selected. Evaluation of exo-miRNAs revealed that only 4 of the 10 miRNAs (miR 29b-3p, 216a-5p, 148a-3p and miR 375) was released 24 hrs post-transplant in a xenogenic kidney capsule transplant model. The release of these exo-miRNAs in the circulation post-transplant was correlated with upregulation of inflammatory genes IP-10, TNFα, IL-6, iNOS, HIF1α and cFOS in the retrieved islet graft. The in silico based KEGG analysis predicted that the exo-miRNAs targets most of the genes related to PI3K/Akt signaling. MiRTRAP analysis revealed that MyD88 (P<0.01), NFKB1 (P<0.01), BAD (P<0.01), PIK3R1 (P<0.01) and IRS1 (P<0.01) were targets of miR 216a-5p and 29b-3p and this was further validated by qPCR

*Conclusions: Exosomal miRNAs released by islets in response to inflammation matched with those released immediately post-transplantation. Moreover, these miRNAs target the PI3K/AKT and NFκB signaling pathways.

To cite this abstract in AMA style:

Saravanan P, Kanak M, Yoshimatsu G, Darden C, Lawrence M, Levy M, Naziruddin B. Analysis of Islet Exosomal miRNAs Released Post-Transplant in Response to Inflammation [abstract]. Am J Transplant. 2019; 19 (suppl 3). https://atcmeetingabstracts.com/abstract/analysis-of-islet-exosomal-mirnas-released-post-transplant-in-response-to-inflammation/. Accessed May 11, 2025.

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