stem cells in their environment

3rd International Annual Conference of the German Stem Cell Network (GSCN)

20 November 2015
By Ruta Meleckyte

I recently had the opportunity to attend the 3rd International Annual Conference of the German Stem Cell Network (GSCN). The conference was held in the Otto Stern Center in Frankfurt for three days (you can find the programme here).

Otto Stern Center in FrankfurtThe conference had a very busy schedule and most of the time I needed to select talks which I wanted to hear and run from one room to another. Here I'll briefly describe talks which I found interesting and, if you'd like to find out more, you can have a look at the full abstracts here.

The first scientific session was about pluripotency, stem cells in regenerative therapies and computational stem cell biology. Talks on therapies were focused mostly on studies of cardiac stem cells and neurons. A very interesting talk was given by Daniela Lehnen, who introduced a novel cell surface marker for dopaminergic neurons for sorting mesDA (mesencephalic dopaminergic neurons).  Alvaro Rada-Iglesias from University of Cologne discussed the role of Foxd3, which is crucial for the exit from naïve pluripotency stage, and Miha Modic from Helmotz Center in Munich showed her research about alternative polyadenylation in pluripotency stage and resumed that TDP-43 keeps pluripotency by regulating of nucleoplasmic NEAT1 short isoform. Simon Hastreiter from Helmotz Center in Munich discussed heterogeneity in single cell levels. He showed that mESC, kept in 2i media had more homogenous Nanog expression levels at the single cell level when compared to standard Serum+Lif condition.

The second day was divided into three parts. The first part had all the scientific group session talks about stem cells in disease modelling and drug development, cancer stem cells and stem cells in development. Wolfgang Wagner very interestingly presented his lab's research on the epigenetic age-predictions in cancer. Using methylation levels they showed that age-associated DNA methylation patterns in cancer are not related to the age of the patient – they rather capture the epigenetic state of aging from the tumor initiating cells. Regulation of these patterns in age-associated CpGs is relevant for cancer development. The second part of the day had industry posters and talks. The most appealing talks given were about weekend-free media (wouldn't it be nice to spend some weekends away from the lab?) and mRNA system for reprogramming.

The end of the day was marked with three scientific awards.  Julia Ladewig from the Institute of Reconstructive Neurobiology in Bonn won the Young Investigator award. Her work is based on in vitro cell culture models to decipher brain development and neuronal integration. She showed that auto-attraction of neurons by neural progenitors inhibits migration of neurons from transplanted cells and it can by blocked by receptor tyrosine kinase inhibition. She is planning to use cortical organoids derived from iPSc from healthy donors and disease patient with defined cortical development defects, to study early aspects of brain development. Her talk was amazing and I can't wait to see her work published in more detail.

Magdalena Goetz from Helmholtz Center in Munich gave a very inspiring talk: 'from neurogenesis to neural repair' and was nominated for the Female Scientist award. Her laboratory applied layer-specific integration of regenerated neurons in mouse with injury. Her aim was to inhibit scarring and introduce new neurons from endogenous sources to fill the gap.  She managed to turn scar-forming cells into neurons and showed that glia cells migrate to the injury. Dr Goetz also used ferroptosis for neuronal reprogramming instead of apoptosis inhibitor, which increases neuron derivation, and raised a lot of questions from the audience.

The Best Publication of the Year 2015 award was given to Jichang Wang from the Max Delbrueck Center in Berlin for his work on primate-specific endogenous retrovirus-driven transcription, which associates with naïve-like pluripotent stem cell.  His article can be found here.

The third day was less hectic but still very informative. Well-known Andreas Nagy presented his lab's work on a new class cell state that he discovered during intense TC work, and published it in Nature in December 2014. He pointed out a few things. Firstly, there is more pluripotent cell state than we think. He defined that we all know classical looking pluripotent cells that can be named C-class cells. But there is at least one more class named called F-class for 'fuzzy' whose cells don't have defined edges of colonies, grow faster, have low adhesion, are able to make teratomas and are positive for Nanog expression. Short HDACi treatment can convert F-class into C-class iPSc, by inhibiting histone deacetylation. Secondly, all cells have a point of no return, which defines cell fate in reprogramming. Any somatic cell can become a pluripotent cell, when introduced with transcription factors and after passing the point of no return, if the transcription factors are not present in the culture, the cell will still become a pluripotent. There's also a point of commitment where a programmed cells commits to pluripotency. It applies the other way around as well, if differentiation factors were removed earlier, but a reprogramming cell already past its point of no return will turn into a terminally differentiated cell even without certain factors present in the media.  He also mentioned an intriguing idea; that during reprogramming it's possible to avoid the pluripotent stage and go straight into your cell of interest.

Summarising all of the talks, posters and chats I had during three days, I can say that there is a lot going on with neuron and mesenchymal cell derivation and usage.

A couple of days ago I found on Professor Knoepfler's blog a word cloud to find the most used word in all articles, which had stem cell(s) in the title.  The word mesenchymal was the one. It wasn't a surprise that most of the posters focused on mesenchymal cells, neurons or hematopoietic cells derived from pluripotent cells. In total there were 147 posters presented in two days! Only six posters reported studies of iPS cells in 3D culture. Many posters were based on disease modelling including Parkinson's, Angelman syndrome and cystic fibrosis.

A few of these, including mine, were about iPS cells, representing data about culture maintenance peculiarities, genetic differences between iPS cell line with different passage number and phenotypic analysis. Preparing a poster was another great experience and new skills gained in one go.

I must say, it was my first ever conference and it was very exciting to have an overview of what is new in stem cell research, listen to amazing talks and meet brilliant minds. The organisers are already planning the 4th international meeting next year some time in the autumn and I recommend checking it out.

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