Troy McDiarmid's Avatar

Troy McDiarmid

@troymcdiarmid

Banting Postdoc with @JShendure @uwgenome | Prev @CIHR_IRSC UBC Neuro PhD | Genome engineering, molecular recording, neurodevelopment and its disorders | Mountains & skateboarding

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17.11.2024
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Latest posts by Troy McDiarmid @troymcdiarmid

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Harnessing heterogeneity for the rational design of cell manufacturing Dorri Nokoorani et al. argue that heterogeneity can be harnessed as a design feature in the quality-by-design toolkit to optimize the yield, quality, and robustness of bioprocesses for manufacturing s...

[Plz πŸ“’] A little late to the party, but check out our perspective on how cellular heterogeneity can be your friend😊 or foe😠 in cell therapy manufacturing🧫. Shout out to Yeganeh, Hourieh, Enzo, Ali, Yonatan: www.cell.com/cell-systems... @sbmeubc.bsky.social

27.02.2026 17:02 πŸ‘ 3 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0

We wrote a perspective "How to build the regulatory genome: a constructionist guide to the cis-regulatory code", out in Development yesterday. Title says it all. Find it here:

journals.biologists.com/dev/article/...

25.02.2026 15:18 πŸ‘ 37 πŸ” 17 πŸ’¬ 1 πŸ“Œ 1

We have significantly improved the protocol for recording CRE activities and orders with ENGRAM. We also designed new plasmids for easier cloning. Great work with @jennynathans.bsky.social, @troymcdiarmid.bsky.social and @jshendure.bsky.social . Happy recording!!

13.02.2026 19:37 πŸ‘ 9 πŸ” 5 πŸ’¬ 0 πŸ“Œ 0

Check out our new protocol paper on molecular recording of transcriptional events in genomic DNA!

Super fun pulling this together with @jennynathans.bsky.social @chenomics.bsky.social and @jshendure.bsky.social

15.02.2026 17:43 πŸ‘ 3 πŸ” 4 πŸ’¬ 0 πŸ“Œ 0

Super happy to share our protocol for ENGRAM is out in Nature Protocols! This was fun to write with @chenomics.bsky.social @troymcdiarmid.bsky.social @jshendure.bsky.social. In it we describe how to record CRE identity, activity, and order in mammalian cells.

13.02.2026 19:31 πŸ‘ 10 πŸ” 5 πŸ’¬ 0 πŸ“Œ 1
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Genome-scale perturb-seq in primary human CD4+ T cells maps context-specific regulators of T cell programs and human immune traits Gene regulatory networks encode the fundamental logic of cellular functions, but systematic network mapping remains challenging, especially in cell states relevant to human biology and disease. Here, ...

Together with @ronghuizhu.bsky.social, we are thrilled to present our new perturb-seq study of 22M primary CD4+ T cells, across donors and timepoints – the result of a decade-long collaboration between the Marson @marsonlab.bsky.social and Pritchard @jkpritch.bsky.social labs 🧡 tinyurl.com/gwt2025

05.01.2026 18:42 πŸ‘ 63 πŸ” 29 πŸ’¬ 2 πŸ“Œ 4

We added several additional experiments using the parts to target alternate loci, measure both transcription and editing, and more.

Great experience working on this with Megan Taylor , @jshendure.bsky.social and co. and very rewarding to see the rapid uptake by the community. Cheers!

12.11.2025 18:08 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

Our work developing a parts list of promoters and gRNA scaffolds for mammalian genome engineering and molecular recording is now out @natbiotech.nature.com

12.11.2025 18:06 πŸ‘ 24 πŸ” 10 πŸ’¬ 1 πŸ“Œ 0
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πŸš€ Very excited to share the first major work from my PhD!!

We combined MPRA and CRISPRa in excitatory neurons to test and validate cis-regulation therapies for hundreds of haploinsufficient neurodevelopmental disorder genes. πŸ§¬πŸ”¬

www.biorxiv.org/content/10.1...

06.11.2025 23:56 πŸ‘ 18 πŸ” 5 πŸ’¬ 1 πŸ“Œ 1

Thanks Sreeparna!

05.11.2025 15:28 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

Thanks to all co-authors on and off bluesky, especially @nadavahituv.bsky.social and @jshendure.bsky.social, as well as the funders and families. Cheers!

05.11.2025 15:26 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

Our results provide a comprehensive resource of active, target-linked human neural enhancers for NDD genes and gRNA reagents for CRT development. More broadly, this work establishes a generalizable strategy for discovering CRT gRNA candidates across cell types and haploinsufficient disorders.

05.11.2025 15:22 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
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Finally, we confirmed that several of the CRISPRa gRNAs identified here demonstrated selective and therapeutically relevant upregulation of SCN2A, CHD8, CTNND2 and TCF4 when delivered virally to patient cell lines, human cerebral organoids, and a humanized mouse model of hTcf4.

05.11.2025 15:21 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
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We identified hundreds of promoter- and enhancer-targeting CRISPRa gRNAs that upregulated 200 of the 337 NDD genes in human neurons, including 91 novel enhancer-gene pairs.

05.11.2025 15:19 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
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Next, we applied multiplex single-cell CRISPRa screening with 15,643 gRNAs to test all MPRA-prioritized cCREs and 761 promoters of NDD genes in their endogenous genomic contexts.

05.11.2025 15:19 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
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We then tested all 5,425 candidate neuronal enhancers with MPRA, identifying 2,422 that are active in human neurons.

05.11.2025 15:18 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
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We first prioritized 337 haploinsufficient NDD risk genes from 42,320 cases. We then nominated 5,425 candidate enhancers for these 337 genes leveraging multiple datasets characterizing the regulatory landscape of the developing human brain, together with various enhancer-gene mapping strategies.

05.11.2025 15:17 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
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Here, we combined Massively Parallel Reporter Assays (MPRAs) and a multiplex single cell CRISPRa screen to discover functional human neural enhancers whose CRISPRa targeting yields specific upregulation of NDD risk genes.

05.11.2025 15:16 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
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However, scaling this cis-regulatory therapy (CRT) paradigm requires pinpointing which candidate cis-regulatory elements (i.e. promoters and enhancers) are active in human neurons, and which can be targeted with CRISPRa to yield specific and therapeutic levels of target gene upregulation.

05.11.2025 15:14 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
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Many neurodevelopmental disorders are caused by haploinsufficiency - where functional loss of one gene copy leaves insufficient expression from the other.

CRISPR-based gene activation (CRISPRa) has emerged as a promising therapeutic approach for NDD caused by haploinsufficiency.

05.11.2025 15:12 πŸ‘ 3 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
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Stoked to share our latest work entitled: β€œLarge-scale discovery of neural enhancers for cis-regulation therapies”

shorturl.at/H3Qww

This is an enormous team effort that I had the honour of spearheading with Nick Page and Florence Chardon.

Bluetorial below.

05.11.2025 15:09 πŸ‘ 34 πŸ” 14 πŸ’¬ 2 πŸ“Œ 3
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Thrilled to share I’ve started my lab at Dartmouth’s Geisel School of Medicine! We focus on mapping cellular trajectories & TF networks in development and Mendelian disorders, exploring new therapies. Join usβ€”postdocs, grads, and scientists welcome! sites.dartmouth.edu/qiulab/

04.11.2025 15:10 πŸ‘ 16 πŸ” 10 πŸ’¬ 2 πŸ“Œ 0

Sometimes I think about how from 1935-1975ish, Bell Labs produced an insane amount of revolutionary science and technology, including 11 Nobel Prizes, the transistor, UNIX, C, the laser, the solar cell, information theory, etc. The secret? Provide scientists with ample, steady, no-strings funding.

04.10.2025 17:35 πŸ‘ 1729 πŸ” 487 πŸ’¬ 51 πŸ“Œ 35
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Check out MitoScribe in our new preprint led by Linhan Wang: www.biorxiv.org/content/10.1...

It's an analog molecular recorder that uses neutral base edits to the mitochondrial genome to store information about historical signaling in a cell. Single cell resolution at scale (see next post)!

08.09.2025 17:13 πŸ‘ 7 πŸ” 5 πŸ’¬ 1 πŸ“Œ 0
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E11 Bio is excited to unveil PRISM technology for mapping brain wiring with simple light microscopes. Today, brain mapping in humans and other mammals is bottlenecked by accurate neuron tracing. PRISM uses molecular ID codes and AI to help neurons trace themselves.

Read more: e11.bio/blog/prism

01.10.2025 14:16 πŸ‘ 59 πŸ” 30 πŸ’¬ 1 πŸ“Œ 11
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After 10 years of work, a complete telomere-to-telomere gap-free genome for C. elegans finally exists: it has 106 Mb rather than the textbook 100.3 Mb, and up to 366 additional genes.
genome.cshlp.org/content/35/8...

01.08.2025 21:55 πŸ‘ 102 πŸ” 37 πŸ’¬ 4 πŸ“Œ 0
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I'll never get tired of these.

(courtesy of Sebasitan Wittekindt doi.org/10.1101/2025...)

26.09.2025 23:06 πŸ‘ 26 πŸ” 4 πŸ’¬ 1 πŸ“Œ 1

Beautiful!

27.09.2025 03:26 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

Well don't I feel stupid

26.09.2025 23:02 πŸ‘ 26028 πŸ” 6826 πŸ’¬ 289 πŸ“Œ 143
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New paper from my lab and @jshendure.bsky.social lab! Led by the brilliant @zukailiu.bsky.social and @cxqiu.bsky.social. We tackled how anterior and posterior progenitor cells cooperate to self-organize into an embryonic structure (termed AP-gastruloid). (1/n) www.biorxiv.org/content/10.1...

26.09.2025 18:06 πŸ‘ 54 πŸ” 20 πŸ’¬ 3 πŸ“Œ 2