Ryszard Wimmer
Dr. in Neurobiology and Cell Biology, interested in how things move in the brain.
Looking at things in the human brain with a touch of live-imaging!
Currently in Institut Curie working on human brain development with a twist on cancer.
- ✨ #FluorescentFriday ✨ SOX2-positive cells forming the heart of the developing human cerebellum 🧡, framed by a glowing outline of PAX6-positive neighbors 💙. A tiny but breathtaking glimpse into brain development under the microscope. 🧠💡
- There is no better place to talk about Radial Glia Cells than on the beaches right under the Etna in Gardini Naxos @corticodevelopment.bsky.social !
- Excellent work from @silvianeuro.bsky.social lab on DCHS1 ! @mveronicapravata.bsky.social congratulations! www.biorxiv.org/content/10.1...
- Reposted by Ryszard WimmerDCHS1 Modulates Forebrain Proportions in Modern Humans via a Glycosylation Change biorxiv.org/content/10.1101/202…
- sciencebank.com/development-... A cool and smooth blog post on stem cell use, validation, quality control and on how to share Your precious stem cells with others! #stemcells I hope You enjoy!
- In the neon glow of the cortex, a Radial Glia stretched its long, guiding arm. Suddenly, a rogue cell snatched a piece of its scaffold, disrupting the neural highway. "Hey!" it pulsed, but the thief vanished into the synaptic shadows. The network flickered—order shaken. #fluorescentfriday
- Reposted by Ryszard WimmerDelighted to have this out as a preprint! Thanks to all authors, especially @estherkli.bsky.social and @djabaudon.bsky.social for leading the work. If you are interested in how conserved genes played a part in evolving human brains, give it a read!
- Reposted by Ryszard WimmerNew preprint out from the lab, check out thread below!
- While waiting on my paper to get rejected or accepted 🤗 I discovered that playing with clay is just a beautiful disconnection from everyday problems. Here is my first take at a flower-shaped candle ! #pottery #nature #flowers #qualitytime #science
- Images and all scientific data needs a voice. @clarissebrunet.bsky.social is running a beautiful podcast in spannish called Ciencia en Voz Alta „Science Out Loud”. It’s a beautiful series of podcasts with scientists on spotify talking about their research! cienciaenvozalta.com Enjoy! 🎧
- Hello! My PhD pre-print is out on biorxiv, where in the Lab of @alexbaffet.bsky.social we managed to unravel how bRG (oRG) cells translocate and colonise the developing human brain. Interestingly features of these translocations are conserved in glioblastoma! Link : www.biorxiv.org/content/10.1...
- Reposted by Ryszard WimmerI want to thank everyone involved in this work on top of Ryszard who did an amazing job. Laure Coquand, Amandine Di Cicco, Christophe Chehade, @clarissebrunet.bsky.social @pauline-lestienne.bsky.social, Julia Ladewig, Karin Forsberg-Nilsson, Fabien Guimiot and our fantastic imaging facility!
- Reposted by Ryszard WimmerUsing 9 different glioblastoma lines we show that IST and MST both occur, although not in all cells, reflecting the heterogeneity of these tumors. Strikingly, glioblastoma undergoing IST and MST did so using the same molecular mechanism as the ones identified here in bRG cells.
- Reposted by Ryszard WimmerFinally, because past work form @bhadurilab.bsky.social and others had shown a facilitating similarity between bRG cells and glioblastoma cells (including the presence of MST), we tested the conservation of our mechanisms in these cells.
- Reposted by Ryszard WimmerTherefore, microtubule related genes are more likely to affect human oSVZ expansion than actin-related ones.
- Reposted by Ryszard WimmerSo MST and IST are totally different mechanisms, but what is their relative contribution to bRG dissemination in the human fetal cortex? After extensive recording in fetal explants, Ryszard could show that IST contributes to 85% of the total basal movement, while MST contributes to 15%.
- Reposted by Ryszard WimmerMechanistically, we demonstrate that MST is dependent on the mitotic cell rounding pathway, that enables most adherent cells to round up for proper chromosome segregation through an increase of the cell cortex stiffness. Knocking down ERM proteins (Ezrin-Radixin-Moesin) or Vimentin all alter MST.
- Reposted by Ryszard WimmerWe next focused our attention on MST and, using Sir-tubulin dyes, first showed that it occurred after nuclear envelope breakdown, and is therefore a mitotic spindle translocation event!!! I find this crazy, and to our knowledge quite unique in biology (so far...).
- Reposted by Ryszard WimmerTogether, this microtubule-dynein-LIS1-LINC pathway generates pulling force and the nucleus, for translocation. Interestingly, this mechanisms is different from INM in aRG cells, but similar to nucleokinesis in neurons. Neuronal migration disorders may therefore also result from bRG cell defects.
- Reposted by Ryszard WimmerWe demonstrate that IST is dependent on the dynein motor and its activator LIS1. Accordingly, IST is severely affected in LIS1-patient derived organoids (Lissencephalic). We also show that the dynein-LIS1 complex is recruited to the nuclear enveloppe (and underlying Lamins) via the LINC complex.
- Reposted by Ryszard WimmerOn top of identifying the mechanism for MST, we realised that bRG cells also translocate during interphase, a process we call Interphasic Somal Translocation (IST). We show that IST is microtubule dependent and actomyosin independent, while MST is actomyosin-dependent and microtubule independant.
- Reposted by Ryszard WimmerbRG cells were known to translocate rapidly during mitosis, a process called Mitotic Somal Translocation (MST). This translocation relies on acto-myosin contractility and was identified by the Kriegstein lab.
- Reposted by Ryszard WimmerGreat work from @ryszardwimmer.bsky.social, who live imaged and manually tracked over 11,000 human bRG cells, for 48-96 hours 😱. (I feel bad) What he realised is that bRG cells have two, totally independent modes of migration, for which he managed to identify the molecular mechanisms.
- Reposted by Ryszard WimmerOur new paper is out in BioRxiv. Using human fetal tissue and cortical organoids, we figured out how human bRG cells colonize the developing neocortex to expand the oSVZ stem cell niche. Turns out, it's a more complex process than we had anticipated! www.biorxiv.org/content/10.1...
