Contact info: Anna Wendt, anna.wendt@med.lu.se
LU research profile: https://portal.research.lu.se/en/persons/anna-wendt
Start date: Any time between September 2025 and January 2026 (can be discussed)
Length of the project : 45 credits
Project type: master project
Additional information: This project is in collaboration with Lena Eliasson who will be co supervisor. Link: https://www.ludc.lu.se/research/diabetes-islet-cell-exocytosis
Project information:
Aim: This project aims to examine the role of microRNAs in intra-islet crosstalk. A special focus will be put on exosome-delivered microRNAs and their effects on insulin- and glucagon secretion.
Hypothesis: We hypothesize that microRNA containing extracellular vesicles (EVs) are released from all cell types in the islets of Langerhans. The EVs then travels through the interstitium to neighbouring islet cells, or via the circulation to recipient islet cells further away. Once they reach their designated recipient cells the EVs are taken up in a regulated fashion and the microRNAs can modulate the physiology of the recipient cell. We believe this to be an important, previously unrecognized layer of islet cell regulation.
Introduction: Dysfunctional glucagon and insulin secretion from islet alpha- and beta cells is a hallmark of type-2 diabetes. Given their crucial role in whole body metabolism, both alpha- and beta cells are tightly regulated through several mechanisms including microRNAs. MicroRNAs are short non-coding stretches of RNA that negatively regulate protein expression. We know from work by us and others that they play an important role in beta cell identity and function and the evidence points to an important role for microRNAs in alpha cells too. MicroRNA regulation has previously been assumed to only occur locally within the same cell, but recent publications have demonstrated microRNAs in the circulation both bound to carrier molecules and contained in exosomes (EVs; extra cellular vesicles). The literature shows that EVs can be taken up by recipient cells and regulate their function by delivering their cargo (microRNAs, but also other regulatory proteins). In this project we will investigate local, EV based, microRNA communication within the islets of Langerhans.
Project plan: In the first part of the project, we will investigate microRNAs that are packaged in EVs and released from islet alpha and beta cells. To establish proof of concept we will expose alpha and beta cell lines to biological stress in the form of glucolipotoxic conditions and cytokine treatment (to mimic the diabetic condition) and to standard cell culture conditions (to mimic the healthy state). The growth medium from the cells will then be collected and all EVs released into the media will be purified using exoEasy (Qiagen). The isolated EVs will then be used for two kinds of experiments. Firstly, we will add purified EVs from the mouse beta cell line (stressed or unstressed) to the alpha cell line, or EVs from stressed beta cells to unstressed. We will then investigate secretory capacity (ability to release insulin or glucagon) in the recipient cells using ELISA, insulin/glucagon expression using ELISA and qPCR, cell viability using an MTS assay, and expression of transcription factors with qPCR. The focus will be on hormone secretion and expression and the other experiments will be performed if the time allows.
Secondly, we will isolate microRNAs from the isolated EVs. In a later step we will determine the identity of the microRNAs using small RNA sequencing but for now, if time allows, we will investigate the presence of some candidate microRNAs.
Significance: The potential role of circulating microRNAs as an additional layer of regulation in islet cells is a novel and largely unexplored concept that could provide important insights into diabetes prediction, development, and treatment.