iiinova — where your digital self keeps evolving

Reposted by James Zwierzynski

Emma R Andersson @anderssonlab.bsky.social · 23/09/2026

🧬 Preprint! 🧵 Our goal is to genetically manipulate every embryonic germ layer to enable high throughput in vivo studies. We previously showed mouse ectoderm can be targeted by amniotic injection, enabling cell-specific manipulation, lineage tracing, and knockouts. But how to reach mesoderm?

Schematic of method developed and application. At embryonic day 7.5, a lentiviral library carrying unique 30-nucleotide barcodes and a fluorescent reporter is injected into the mouse exocoelomic cavity. An E8 embryo cross-section shows that this cavity is continuous with the intraembryonic coelomic cavity, allowing the virus to reach and barcode mesodermal progenitors, including lateral plate and paraxial mesoderm.

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James Zwierzynski @jamesbzsci.bsky.social · 08/09/2026

A wonderful past two weeks, presenting my work at the 10th Anniversary @HHMIJanelia / @embl Imaging Mouse Development Conference, submitting the DP5, and doing plenty of hiking after turning the big 3-0 and celebrating with a visit from my mom! Onto the best decade yet!

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James Zwierzynski @jamesbzsci.bsky.social · 28/08/2026

#FluorescenceFriday! Light sheet of the whole guinea pig uterus at E9.5 -epithelium (CK7, teal), smooth muscle (SMA, yellow). The middle pit is a uterine crypt where the embryo implanted and is undergoing gastrulation. These beautiful gland projections seen are key regulators of these processes too!

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Reposted by James Zwierzynski

@NicoliLab @nicolilab.bsky.social · 17/08/2026

🎉 It’s official! Vascular Cell Biology GRC 2027 is live!🎉 Join us January 10–15, 2027, in Ventura, California🌞 “Vascular Resilience: Mechanisms, Function, and Disease” Incredible group of scientists, many new ideas all focused on understanding how to build resilient blood vessels! 📢 PLEASE REPOST!📣

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James Zwierzynski @jamesbzsci.bsky.social · 28/05/2026

Looking to join a collaborative team studying coronary artery development? Love taking pretty microscope images? The Red-Horse lab(@hhmi-science.bsky.social/Stanford) is hiring for a senior scientist to research coronary & collateral artery development apply below!: tinyurl.com/5d85xjze

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Reposted by James Zwierzynski

Dr Kathleen Millen @neurodevkathy.bsky.social · 20/05/2026

🚨🧪🧵URGENT INPUT NEEDED: NIH asks input for next strategic plan-including emphasis on non-animal models (NAMs) to replace animals. Per NIH insider, anti-animal responses now outnumber scientists 200-700x. Please please provide input. Deadline: May 26, 11:59 PM ET. grants.nih.gov/news-events/...

grants.nih.gov

NIH Seeks Input on Framework for Next NIH-Wide Strategic Plan | Grants & Funding

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Reposted by James Zwierzynski

Molly Schumer @mollyschumer.bsky.social · 12/05/2026

Do you know any students who are planning to apply to graduate school this cycle? Encourage them to apply to the Biology Preview Program! We provide intensive workshops to help students w/ their applications + 1:1 mentorship.

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James Zwierzynski @jamesbzsci.bsky.social · 04/05/2026

Why do guinea pigs naturally develop collateral arteries while other species don't? Check out this wonderful preprint from our lab using in vivo Peturb-seq to discover differences in tip cell programming contribute to artery formation in guinea pig development!

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James Zwierzynski @jamesbzsci.bsky.social · 13/04/2026

If this work is interesting to you, we're hiring for a Senior Scientist with post-doctoral experience and a background in RNA molecular biology or whole-organ imaging and analysis to join our small, collaborative team! Come take more pretty pictures with us! Interested applicants should apply below:

careersearch.stanford.edu

Basic Life Research Scientist in School of Humanities and Sciences, Stanford, California, United States

Basic Life Research ScientistThis position has been deemed critical by the School of Humanities and Sciences Dean’s Office and is exempt from the...

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James Zwierzynski @jamesbzsci.bsky.social · 12/04/2026

Thank you - and yes, we totally agree!

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James Zwierzynski @jamesbzsci.bsky.social · 12/04/2026

This paper was a product of intense work by the three of us, and we are very excited to share it with everyone! Of course, a huge thank you goes out to our funding sources, and especially everyone who has given us feedback, advice, and comments along the way.

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James Zwierzynski @jamesbzsci.bsky.social · 12/04/2026

There is sparse evidence for decidual CXCR4's function, so CXCR4 activation in decidual cells surprised us. However, beautiful work out this week in Nature shows a population of CXCR4+ human decidual cells associated with blood vessels & pregnancy complications - exciting parallels to what we see!

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James Zwierzynski @jamesbzsci.bsky.social · 12/04/2026

We find an arterial defect emerges soon after this; we think this presents a model for understanding how early pregnancy defects manifest in late-gestation syndromes. Most importantly, we see work opening a new understanding of mouse placentation and invasion - which we can't fait to follow up on!

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James Zwierzynski @jamesbzsci.bsky.social · 12/04/2026

While we find many symptoms of PAS arising in these mice in late gestation, we sought to understand what the initial insult might be. Clinical hypotheses suggest defective decidualization underlies this syndrome, and we indeed find this in early gestation in our model.

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James Zwierzynski @jamesbzsci.bsky.social · 12/04/2026

Most surprisingly, these mice showed invasion of placental cells into the deep myometrium and myometrial arteries, a phenotype reminiscent of human placenta accreta spectrum (PAS) disorder. We validated this over-invasion using fetal cell labeling and pharmacologic approaches.

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James Zwierzynski @jamesbzsci.bsky.social · 12/04/2026

Interestingly, these embryos die in late gestation, but appeared grossly normal here (E12.5). 3D imaging revealed that loss of fetal Cxcl12 mispatterned the maternal-fetal interface, with arteries and trophoblasts pushed to the periphery rather than central region.

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James Zwierzynski @jamesbzsci.bsky.social · 12/04/2026

To test for the role of this placental Cxcl12, we deleted the fetal gene, and found hypoplastic placentas with few arteries and invasive trophoblasts. We pharmacologically validated through CXCR4 inhibition that this interaction was most essential in early pregnancy.

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James Zwierzynski @jamesbzsci.bsky.social · 12/04/2026

Which molecules control this growth? We found our favorite chemokine, Cxcl12, was expressed transiently in the early placenta; while its cognate maternal receptor was activated on surrounding decidual cells, and newly forming arteries.

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James Zwierzynski @jamesbzsci.bsky.social · 12/04/2026

As vascular biologists, we were interested in understanding where this beautiful artery growth we visualized was sourced from, and we found that they were primarily sourced from capillary progenitors undergoing an arterial fate acquisition in early pregnancy.

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James Zwierzynski @jamesbzsci.bsky.social · 12/04/2026

We analyzed the positions of arteries & trophoblasts, benchmarked to placental anatomical landmarks. We found that trophoblast invasion skews in random directions, not always aligned directly with artery positioning. So, individual 2D tissues sections may lie in planes which miss this nuance.

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James Zwierzynski @jamesbzsci.bsky.social · 12/04/2026

Why have we missed this in the mouse? A logical explanation is the optical clarity resolved by 3D imaging. However, we also found a biologically-rooted explanation – arteries persist in the mature placenta in regular patterns – but trophoblast invasion occurs with random bias.

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James Zwierzynski @jamesbzsci.bsky.social · 12/04/2026

Using 3D whole-organ, light sheet imaging, we find that instead trophoblast invasion is underestimated by 4-5-fold by traditional 2D analyses. Through this approach, we find a beautiful progression of arterial growth towards the placenta over gestation, accompanied by massive trophoblast invasion.

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James Zwierzynski @jamesbzsci.bsky.social · 12/04/2026

Dogma has long held that the mouse is a poor model of deep placentation that is observed in humans, due to shallow trophoblast invasion and poor arterial tropism of those trophoblasts. We wanted to test this, so I adapted an improved light-sheet imaging protocol for whole implantation sites.

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James Zwierzynski @jamesbzsci.bsky.social · 12/04/2026

I'm now on Bluesky!🤗 Excited to share our preprint, reviving Kristy Red-Horse's interest in the placenta from her PhD ~20 years ago! We find using 3D imaging that the mouse placenta is far more invasive than previously thought. Furthermore, we find a surprise from our favorite chemokine CXCL12...🧵:

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