Exosomes from store-bought liver

[Andreas "Mega" Stuermer]

Hi guys! 

Wondering the following: 

If you buy liver from the store, it's been sitting on 4°C for a few days... 

Wondering if you can still extract exosomes and proteins from inbetween the cells and how you would go about it. 

I mean, exosomes are pretty stable for what I remember - at least they survive freezing. There's also this protein called MSA which might be the activity we want(?) 

The idea here is that usually you use "pre-conditioned" medium for stem cells. -> You grow buffalo rat liver cells in tissue culture, add fresh medium and wait a few hours until the cellls released ome exosomes and proteins. Then, the hardly-used medium is removed and stored for later use, so you can grow stem cells in it

"Buffalo rat liver cells produce a diffusible activity which inhibits the differentiation of murine embryonal carcinoma and embryonic stem cells."

https://www.ncbi.nlm.nih.gov/pubmed/3569655

[Gordana Ostojic]

Andreas, 

I attached paper about exosome isolation techniques: basically extraction kit (expensive if I remember correctly) and size exclusion. No personal experience with either. 

[Ravasz]

Hi there,

When I worked with exosomes we used a combination of filtration and ultracentrifugation to isolate them. Ultracentrifuges are usually not available for DIY bio labs.

Secondly, isolating exosomes from tissue is quite problematic. We used a clean cell culture with specially prepared medium, and purified exosomes from there. Even then there was always a level of contamination in the sample from particles that are not exosomes but are similar in size and have similar characteristics (apoptotic bodies, cell fragments, protein aggregates, extracellular matrix pieces). If you start with a tissue the amount of such contaminants will be high, and I don't think you can get any reasonably pure exosome prep from them.

The protocol you describe also uses a cell culture not a tissue. I think growing cultures in a dish and isolating exosomes from the supernatant is doable but difficult, but doing it straight from tissue is not going to work well. That is my guess anyway.

Best Wishes,

Mate

[Andreas "Mega" Stuermer]

Ok, thank you! 

Kind of what I assumed - maybe we'll try it out and compare within the next year or so