No.  But the MSCs can be cultured as Colony forming units ( CFU-F) ( F for fibroblast), in semisolid gel systems, and is a characteristic feature of MSCs to identify MSCs retrospectively.

Thank you. I heard of the CFU MSC on semisolid gels but in my case I have them in tissue culture plasticware without coatings, on MesenPro and they form these colonies even at low confluency.

Hi Ramon,

Have a look at the photo that I have attached to this email. Is this the sort of thing you mean? We have observed these in cultures of MSC (this picture is adipose derived).

Cheers,

Chris

Chris! that is exactly what i am talking about, you nailed it! Do you know if this colony forming cells are any different in potency than the ones that don't form this clusters?

Thankfully,

Ramon

Hi all,

interesting discussion. I think, yes, if you culture the cells in 3D hydrogel they tend to form spheres if you provide serum. If you culture on plastics they just proliferate on the plastic.

Hi Ramon,

MSCs tend to form that sort of colonies (or clumps), it' s a feature of fibroblastoid cells (mesangial cells and fibroblast tend to due the same, even tough at a less rate), these colonies are not embryoid bodies and they are not pluripotent at all, if you analyze them (FACS or IF), you will see that they are exactly as the other MSCs that grow as a single layer, there is no difference at all.

Let me know if you need anything else,

Letizia

Letizia hit the nail on the head.  MSC clusters do not exhibit multi-lineage potential and thus are not embryoid bodies.

Cheers,

JBMIV

Dear Ramon (and others).

We have noted clear differences between these clusters of cells and standard MSC grown in monolayer culture. These clusters are very different to CFU-F, and so are the cells within them. We have observed that the cells that form these spheres are a specific subset of cells which may have specific functional advantages when compared to standard MSC.

This has also been observed by other groups such as this paper;

http://www.ncbi.nlm.nih.gov/pubmed/23623496

Hope this helps,

Chris

MSC don't form EB colonies because this ability is one of the pluripotency marker.

they show fibroblastic morphology in vitro culture

Yes it's true MSCs from different source react differently.....In my experience this is probably due to their very dynamic nature which differs from source to source, from one microenvironment to the other; however, one common characteristic of all MSC sub-sets is their ability to actively interact with other cells and the environment the growth with....

In our hands the various clonal populations of stem cells we examined over the years never formed the "embryoid bodies" similar to the entities that are formed by embryonic stem cells or induced pluripotent stem cells. Rather they would form colonies of cells as they begin to differentiate into either cartilage nodules or bone nodules or clusters of cells to form patches of unilocular or multilocular fat cells. My lab clones by single cell serial dilution clonogenic analysis using conditioned medium. Others that “clone” use a method called “ring cloning”. Ring cloning was initially used in hybridoma technology to identify populations of cells that would secrete the same antibody. In this technique multiple cells are plated into a culture dish and then examined 3-4 days later to find clumps of cells, which they designate as “clonal populations” of cells. What they actually have (we tested this with mixed labeled and unlabeled cells) are not clumps of cells derived from a single cell, but rather a mixture of similar or dissimilar cell types that have migrated towards each other to supply the necessary paracrine factors for their continued growth and well-being in culture using fresh culture medium. Unfortunately the ring cloning method has been perpetuated in the literature for cloning stem cells because it is a far easier and less time consuming method to perform than first generating conditioned medium and then cloning from single cells. My personal opinion is that any data generated from cells that were “cloned” using the ring cloning method is suspect.

You could check the work of Erik Vrij and Nicolas Rivron (group op van Blitterswijk). They are working on embroyonic bodies/cavitation/blastocyst fromation etc. Maybe that helps?