PhD Scientific Days 2020

Molecular Sciences II. Lectures

Extracellular Vesicles Transmit Epithelial Growth Factor Activity in the Intestinal Stem Cell Niche

Előadó neve

Oszvald, Adam, MSc

Előadó munkahelye

Department of Genetics, Cell- and Immunbiology

Előadó telefonszáma

+36304848614

Előadó e-mail címe

oszvald.adam@gmail.com

Az előadás címe

Extracellular Vesicles Transmit Epithelial Growth Factor Activity in the Intestinal Stem Cell Niche

Szerző(k) neve és munkahelye

Adam Oszvald1, Wiener Zoltan2
1 Semmelweis University, Department of Genetics, Cell- and Immunbiology
2 Semmelweis University, Department of Genetics, Cell- and Immunbiology

Szekció

Molecular Sciences II. Lectures

Language of the presentation

English

Section, first choice

Molecular Sciences

Section, second choice

Theoretical and Translational Medicine

Összefoglaló szövege

The intestinal epithelium is continuously renewing by a proliferating stem cell population, residing at the bottom of the intestinal crypts. Intestinal stem cells (ISC) critically depend on niche factors, such as R-Spondin1, noggin and EGF, secreted into the surrounding microenvironment by intestinal fibroblasts or Paneth cells. Three-dimensional organoid culture technology has emerged as a novel, cutting edge tool to study ISCs. Stem cell containing intestinal crypts form self-organizing organoids called „miniguts” after embedded into 3D matrix. Extracellular vesicles (EV) are membrane-enclosed vesicles secreted by virtually all cell types. Although understanding factors critically contributing to the ISC niche is central for regenerative medicine, the effect of EVs on this process is unknown.

To investigate the role of fibroblast-derived EVs in the normal ISC niche.

EVs were isolated by differential ultracentrifugation from fibroblast culture supernatants and they were added to murine small intestinal, colon or to human colon organoids. Organoid survival ratios were quantified by microscopy. Surviving stem cell ratios were determined by confocal microscopy. EV surface proteins were detected by capillary-based Western blot or bead based flow cytometric assays.

Here we provide evidence that both mouse and human intestinal fibroblasts secrete EVs. Fibroblast-derived EVs do not increase the number of ISCs when all niche factors are present. We observed a massive organoid death when niche factors were removed from the culture medium one-by-one. Fibroblast-derived EVs could rescue organoid death in the absence of EGF, but they had no effect when either R-Spondin1 or noggin lacked both in mouse and human intestinal organoids. EVs mediated their rescue effect through the EGF-receptor, which became phosphorylated when EGF was replaced by EVs. Importantly, fibroblasts express a wide range of EGF family members and we found that at least one of them, amphiregulin is transported via EVs. Neutralizing EV-bound amphiregulin blocked the rescue effect of EVs. Furthermore, EVs had no additional effect when EGF was dispensasble, such as after the tumour initiating APC mutations.

We provide evidence that fibroblast-derived EVs are key players in forming the ISC niche by transmitting EGF activity both in mice and in human.

Additional Information

Supervisor: Zoltan Wiener, Semmelweis University, Department of Genetics, Cell- and Immunbiology

Results were published in Stem Cells, 2019, doi: https://doi.org/10.1002/stem.3113

This work was funded by OTKA-NN 118018 (National Research, Development and Innovation Office, Hungary) and by the National Excellence Program in Higher Education (Ministry of Human Resources, Hungary).

Bemutatás módja

Szóbeli

Kind

Szabad

Status

elfogadva

Accepted presentation method

szóbeli

Előadás fájl jóváhagyás

nem rendelkezett róla

Előadó

4628

Start

12:35

End

12:50

Authors (legacy)

Adam Oszvald1, Wiener Zoltan2
1 Semmelweis University, Department of Genetics, Cell- and Immunbiology
2 Semmelweis University, Department of Genetics, Cell- and Immunbiology