Claire Masson

Check out this beautiful thread 🧵 and links to the study 📚
Awesome work on the life of megakaryocytes, very funny cells !
Lead by @wclairemasson.bsky.social !

Megakaryocytes assemble a three-dimensional cage of extracellular matrix that controls their maturation and anchoring to the vascular niche Megakaryocytes form a 3D cage of laminin and collagen IV that stabilizes them within their vascular niche, while β1/β3 integrins and MMP are key regulators that assist megakaryocyte maturation and int...

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Want to dive deeper? 🧠
Read the full story here 👉
elifesciences.org/articles/104...
Huge thanks to all co-authors and collaborators for this amazing scientific adventure 🙏
@renaudpoincloux.bsky.social @goetzjacky.bsky.social @naelosmani.bsky.social
Always happy to discuss!

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⚖️ So, the balance of ECM remodeling is key:
Too loose → MKs escape.
Too tight → MKs can’t mature.
The ECM cage is a dynamic scaffold that fine-tunes megakaryocyte function and platelet formation.

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What if we make the cage too dense?
When we inhibit matrix metalloproteinases (MMPs), the ECM cage becomes denser — and MKs fail to mature properly.
Result: more small, immature MKs accumulate in the bone marrow.

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But why build a cage around MKs? 🤔
We used mice with integrin β1/β3 knocked out specifically in MKs and found that these receptors are essential for cage formation.
Without them, MKs lose their anchorage — and some even enter the bloodstream intact!
➡️ Integrins keep MKs grounded.

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Using high-resolution 3D imaging, we mapped ECM proteins around MKs.
Surprisingly, laminin and collagen IV form a 3D cage that completely surrounds MKs and connects to the sinusoidal basement membrane.
👉 This “ECM cage” stabilizes MKs in their vascular niche.

a man wearing a crown is talking to another man wearing a party hat ALT: a man wearing a crown is talking to another man wearing a party hat

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We know that the ECM is a major component of the bone marrow, especially in the basement membrane.
But what is its role in megakaryocyte maturation and platelet production?
💡 Spoiler: ECM and MK work hand in hand to ensure efficient platelet release.

1/ 👩‍🔬The megakaryocyte (MK) is a fascinating giant cell that produces platelets in the bone marrow.
Situated near sinusoids, it extends long cytoplasmic protrusions that cross the vessel wall — these fragment into platelets, while the nucleus stays in the stroma.

It’s official! 🎉
Our latest paper on the role of the extracellular matrix (ECM) in megakaryopoiesis is out in @elife.bsky.social !
🔗 elifesciences.org/articles/104...
I’m thrilled to share this story with you in a short thread 👇

Blocking tubulin detyrosination via VASH1-SVBP inhibition enhances proplatelet formation & boosts platelet counts—no impact on function. A novel understanding of the megakaryocyte tubulin code beyond tubulin isotypes. #Platelet #HemeSky www.jthjournal.org/article/S153...

It was an honor and a pleasure to share our work on the impact of PACSIN2 on megakaryocyte and erythrocyte development yesterday afternoon at ISTH 2025! #ISTH2025

Awestruck by these cage-like structures that regulate escape of megakaryocytes from bone marrow into blood vessels.

Congratulations to authors of this study, which I see is now also available as a reviewed preprint at eLife: elifesciences.org/reviewed-preprints/104963v1

Thanks again for the PreLight!
I’m thrilled to see our work getting noticed and generating so much excitement!

Megakaryocytes assemble a three-dimensional cage of extracellular matrix that controls their maturation and anchoring to the vascular niche - preLights The megakaryocyte: trapped in a cage of its own making

The megakaryocyte: trapped in a cage of its own making 𐂺

In this #preprint, @wclairemasson.bsky.social & colleagues report the discovery of novel structures controlling megakaryocyte protrusion events.

Excellent #preLight from @simoncleary.bsky.social ⬇️ 👀
prelights.biologists.com/highlights/m...

Wow, what a wonderful four months it has been! Thank you again to Dr. Eckly and her awesome electron microscopy team for hosting me in Strasbourg, FR. I am excited to bring back what I have learned, and I hope to return soon!
#UMRS 1255

It was a pleasure to meet you and to have you in our team ! I hope to see you soon too ! 😊

Interested in #ECM & #platelet biology ?
Check out our latest reviewed #preprint at @elife.bsky.social
A wonderful story lead by A.Eckly and @wclairemasson.bsky.social @inserm.fr where we had a minor contribution
Interesting to participate in the new @elife.bsky.social publishing scheme

First post on bluesky goes out to a wonderful annual science retreat that I had the pleasure of attending for UMRS 1255!