Sign in

Niklas Kempynck

@niklaskemp.bsky.social
138 followers 129 following 28 posts

PhD Student at the Stein Aerts Lab of Computational Biology. Studying brain genomics

PostsRepliesMedia
Niklas Kempynck @niklaskemp.bsky.social · 16/04/2026
Really amazing work and a big effort by Olga, Alex, Julie, Koen and many others. Check it out for sure!
030
Reposted by Niklas Kempynck
cxqiu.bsky.social @cxqiu.bsky.social · 09/04/2026
New preprint @cxqiu.bsky.social @jshendure.bsky.social ! Can we learn regulatory grammars of human cell types — by training on mouse development and transferring across 241 mammalian genomes? Introducing STEAM & a whole-organism scATAC-seq atlas from E10 to birth. www.biorxiv.org/content/10.6...
15127
Niklas Kempynck @niklaskemp.bsky.social · 08/04/2026
Fun fact: CREsted is named after the great crested newt, which has a crested back resembling scATAC peaks. This was inspired by the (alpine) newts I occasionally encounter in my parents' garden 🤗
040
Niklas Kempynck @niklaskemp.bsky.social · 08/04/2026
... and to @steinaerts.bsky.social for his guidance throughout the project.
100
Niklas Kempynck @niklaskemp.bsky.social · 08/04/2026
This work was done together with @seppedewinter.bsky.social, and we’d like to thank @casblaauw.bsky.social, @lukasmahieu.bsky.social, Vasilis, @erencaneksi.bsky.social, @samdieltiens.bsky.social, @darinaabaffy.bsky.social and all the amazing co-authors for their help...
110
Niklas Kempynck @niklaskemp.bsky.social · 08/04/2026
Compared to the preprint we added robustness analyses and more benchmarking of options within CREsted and of CREsted features (like motif identification) to traditional methods. We also aimed to position it well in the landscape of sequence-based modeling methods.
100
Niklas Kempynck @niklaskemp.bsky.social · 08/04/2026
CREsted is finally out! You can find the article, together with a summarizing Research Briefing, in thread. 🦎
12814
Niklas Kempynck @niklaskemp.bsky.social · 09/02/2026
Big thanks to Nelson & Trygve for guiding me, and to all the other people in the group for the nice collab. Thanks to @steinaerts.bsky.social for supporting me on this endeavor and to @fwovlaanderen.bsky.social for funding it. Also, Pacific Northwest nature is quite insane 😁
030
Niklas Kempynck @niklaskemp.bsky.social · 09/02/2026
These studies have many more interesting analyses, so would highly recommend to check out these big efforts from all the people involved! It was great to work together with all the people in Trygve’s group, on our shared interest of trying to understand gene regulation in the brain.
110
Niklas Kempynck @niklaskemp.bsky.social · 09/02/2026
Finally, in a study led by Yuanyuan & Nelson we dove deep into astrocytes subgroups in the BG, and pushed CREsted models to their resolution limit to learn how these subgroups differ in enhancer logic. A very fun adventure with great data and many modalities, and a nice set of enhancer tools.
biorxiv.org
110
Niklas Kempynck @niklaskemp.bsky.social · 09/02/2026
Next, another big atlas release led by Nelson and Yuanyuan on the primate basal ganglia (BG), where again we described enhancer codes of the strongly conserved groups across species and checked how well the models could predict enhancer tool function.
biorxiv.org
110
Niklas Kempynck @niklaskemp.bsky.social · 09/02/2026
First, a study led by @mtvector.bsky.social and Nelson generated a cross-species multiome atlas of the spinal cord, where we described enhancer codes of identified groups with strong conservation across species. We used our models to study enhancer tools for targeting specific cell types.
biorxiv.org
120
Niklas Kempynck @niklaskemp.bsky.social · 09/02/2026
Last summer I spent 4 months working at the @alleninstitute.org as a Visiting Scientist. Recently we released some preprints about the work we collaborated on, where from new multiome atlases of CNS regions we tried to decipher underlying enhancer logic with CREsted (among many other things). (1/n)
1183
Reposted by Niklas Kempynck
Hannah Dickmänken @hannahdckmnkn.bsky.social · 29/01/2026
Paper alert! 💻 How many cells do you need to train reliable deep learning models in regulatory genomics? We asked how data quality, sequencing depth, and dataset size affect training of sequence-to-function models from scATAC-seq. Out now www.nature.com/articles/s41... (details below)
nature.com
Evaluating single-cell ATAC-seq atlasing technologies using sequence-to-function modeling - Nature Communications
Generating high-quality training data for machine learning is costly. Here, authors include sequence-to-function modeling in benchmarking of custom and commercial droplet-based scATAC platforms, and r...
23417
Reposted by Niklas Kempynck
Seppe De Winter @seppedewinter.bsky.social · 15/01/2026
We are thrilled to share our new pre-print: “System-wide extraction of cis-regulatory rules from sequence-to-function models in human neural development”. S2F-deeplearning models can accurately encode enhancers, yet decoding these models into human-interpretable rules remains a major challenge.
14521
Reposted by Niklas Kempynck
Matthew Schmitz @mtvector.bsky.social · 20/10/2025
Relieved to finally post my whole developing brain evolutionary "theory of everything" preprint! www.biorxiv.org/content/10.1...
biorxiv.org
ANTIPODE Provides a Global View of Cell Type Homology and Transcriptomic Divergence in the Developing Mammalian Brain
Diverse neurons and glia are generated in conserved spatial and temporal sequences during mammalian brain development. Divergence in gene regulatory networks can alter brain composition, scaling, timi...
152
Reposted by Niklas Kempynck
Stein Aerts @steinaerts.bsky.social · 23/09/2025
We have two open positions for a ML and a LLM engineer to launch a machine learning expertise unit in our center @vibai.bsky.social, see vib.ai/en/opportuni...
vib.ai
067
Reposted by Niklas Kempynck
scverse @scverse.bsky.social · 10/09/2025
We will have our next community meeting on Tuesday, 2025-09-16 at 18:00 CEST! Niklas Kempynck will be presenting on CREsted, a package for training enhancer models on scATAC-seq data. (Zoom registration link and more information in thread!) 🧵
172
Reposted by Niklas Kempynck
Jacob Schreiber @jmschreiber91.bsky.social · 03/06/2025
I wrote a quick application note on Tomtom-lite, a Python implementation of the Tomtom algorithm for comparing PWMs against each other. This implementation can be 10-1000x faster and, as a Python function, can be integrated into your workflows easier. www.biorxiv.org/content/10.1...
biorxiv.org
Tomtom-lite: Accelerating Tomtom enables large-scale and real-time motif similarity scoring
Summary Pairwise sequence similarity is a core operation in genomic analysis, yet most attention has been given to sequences made up of discrete characters. With the growing prevalence of machine lear...
25818
Reposted by Niklas Kempynck
Stein Aerts @steinaerts.bsky.social · 21/05/2025
One thousand candidate enhancers tested in vivo in the mouse brain! A massive resource and oh so useful as validation set for genome-wide enhancer prediction methods. Super fun to be involved in one of the papers: ‘the prediction challenge paper’ by Nelson&Niklas et al www.cell.com/cell-genomic...
cell.com
Evaluating methods for the prediction of cell-type-specific enhancers in the mammalian cortex
Johansen et al. report the results of a community challenge to predict functional enhancers targeting specific brain cell types. By comparing multi-omics machine learning approaches using in vivo data...
04213
Niklas Kempynck @niklaskemp.bsky.social · 21/05/2025
Make sure to also check out the other studies part of the larger effort on identifying and validating enhancer tools.
000
Niklas Kempynck @niklaskemp.bsky.social · 21/05/2025
This study was done together with Nelson Johansen and supervised by Trygve Bakken at the @alleninstitute.org. Thanks to all co-authors for the great inter-lab collaboration! Also a personal shoutout to the members in @steinaerts.bsky.social lab for a nice team effort and to Stein for guidance.
120
Niklas Kempynck @niklaskemp.bsky.social · 21/05/2025
Check out our work on evaluating methods for predicting in vivo cell enhancer activity in the mouse cortex! Combined, scATAC peak specificity and sequence-based CREsted predictions gave the best predictive performance, aiming to advance genetic tool design for cell targeting in the brain.
cell.com
Evaluating methods for the prediction of cell-type-specific enhancers in the mammalian cortex
Johansen et al. report the results of a community challenge to predict functional enhancers targeting specific brain cell types. By comparing multi-omics machine learning approaches using in vivo data...
12010
Reposted by Niklas Kempynck
Quanta Magazine @quantamagazine.org · 07/04/2025
Calling someone bird-brained is, in fact, a way of calling someone highly intelligent. @yaseminsaplakoglu.bsky.social reports: www.quantamagazine.org/intelligence...
quantamagazine.org
Intelligence Evolved at Least Twice in Vertebrate Animals | Quanta Magazine
Complex neural circuits likely arose independently in birds and mammals, suggesting that vertebrates evolved intelligence multiple times.
18924
Reposted by Niklas Kempynck
Stein Aerts @steinaerts.bsky.social · 04/04/2025
Very proud of two new preprints from the lab: 1) CREsted: to train sequence-to-function deep learning models on scATAC-seq atlases, and use them to decipher enhancer logic and design synthetic enhancers. This has been a wonderful lab-wide collaborative effort. www.biorxiv.org/content/10.1...
biorxiv.org
CREsted: modeling genomic and synthetic cell type-specific enhancers across tissues and species
Sequence-based deep learning models have become the state of the art for the analysis of the genomic regulatory code. Particularly for transcriptional enhancers, deep learning models excel at decipher...
510939
Niklas Kempynck @niklaskemp.bsky.social · 04/04/2025
Also check out Hannah’s thread on our latest preprint on HyDrop v2, an open-source platform for scATAC-sequencing, and a great, cost-efficient way of generating data for S2F models. 🙌
071
Niklas Kempynck @niklaskemp.bsky.social · 03/04/2025
CREsted is available at github.com/aertslab/CRE.... Analysis notebooks can be found at github.com/aertslab/CRE.... All models developed for this preprint and in previous work are available in CREsted through crested.get_model(). We look forward to your feedback!
021
Niklas Kempynck @niklaskemp.bsky.social · 03/04/2025
This was a big collaborative effort, together with @seppedewinter.bsky.social , and with great contributions from @casblaauw.bsky.social , Vasilis and many others. A special shoutout to @lukasmahieu.bsky.social who professionalized the package, and to @steinaerts.bsky.social for supervising.
110
Niklas Kempynck @niklaskemp.bsky.social · 03/04/2025
Finally, we train a model on a full-development zebrafish scATAC-seq atlas, and use it to design and in vivo validate cell type- and timepoint-specific enhancers with a high success rate. We also attempt to modulate reporter strength over two cell types.
130
Niklas Kempynck @niklaskemp.bsky.social · 03/04/2025
In a new functionality to CREsted, we explore Borzoi fine-tuning to mouse motor cortex scATAC-seq data. We show that fine-tuned models and smaller models from scratch have a near-identical performance.
110
Niklas Kempynck @niklaskemp.bsky.social · 03/04/2025
We also study enhancer code inside human cancer cell lines and glioma biopsies and find that enhancer codes between Mesenchymal-like glioblastoma and melanoma states are more similar compared to glioblastoma biopsy data.
110
Niklas Kempynck @niklaskemp.bsky.social · 03/04/2025
Next, we validated CREsted-identified motif instances from a human PBMC model with ChIP-seq data. We further show that gene locus predictions can be used to simulate the effect of TF degradation on chromatin accessibility.
110
Niklas Kempynck @niklaskemp.bsky.social · 03/04/2025
We use the mouse cortex model to highlight CREsted’s gene locus prediction capabilities, both in unseen chromosomes and across species. This presents a powerful tool for potentially annotating genomes across species at high resolution.
110
Niklas Kempynck @niklaskemp.bsky.social · 03/04/2025
We first demonstrate CREsted’s functionality by providing a complete data-driven analysis of mouse motor cortex enhancer codes across cell types. Through matched scRNA-seq data, we link motifs to likely TF candidates.
120
Niklas Kempynck @niklaskemp.bsky.social · 03/04/2025
CREsted starts from the outputs of established scATAC preprocessing pipelines, and trains sequence-to-function models on chromatin accessibility per cell type. It provides complete motif analysis tools to infer cell type-specific enhancer codes and holds a comprehensive enhancer design toolbox.
120
Niklas Kempynck @niklaskemp.bsky.social · 03/04/2025
We released our preprint on the CREsted package. CREsted allows for complete modeling of cell type-specific enhancer codes from scATAC-seq data. We demonstrate CREsted’s robust functionality in various species and tissues, and in vivo validate our findings: www.biorxiv.org/content/10.1...
17538
Reposted by Niklas Kempynck
Blanca Lorente-Echeverría @blancalorente.bsky.social · 31/03/2025
Very excited to share our new preprint together with @daniedaaboul.bsky.social, where we studied the gene regulatory code that hippocampal granule cells (GCs) use during synapse formation (1/n)
2158
Reposted by Niklas Kempynck
Kaessmann Lab @kaessmannlab.bsky.social · 16/03/2025
How does gene regulation shape brain evolution? Our new preprint dives into this question in the context of mammalian cerebellum development! rb.gy/dbcxjz Led by @ioansarr.bsky.social, @marisepp.bsky.social and @tyamadat.bsky.social, in collaboration with @steinaerts.bsky.social
419270
Reposted by Niklas Kempynck
Aligning Science Across Parkinson's @asapresearch.parkinsonsroadmap.org · 13/02/2025
The latest Discover ASAP episode dives into "Cell Type Directed Design of Synthetic Enhancers," a study published in Nature by CRN Team Voet. They discuss how machine learning enables precise enhancer design for targeted gene expression 🧬 Watch: www.youtube.com/watch?v=Qcms...
063
Reposted by Niklas Kempynck
Seppe De Winter @seppedewinter.bsky.social · 28/02/2025
We wrote a review article on modelling and design of transcriptional enhancers using sequence-to-function models. From conventional machine learning methods to CNNs and using models as oracles/generative AI for synthetic enhancer design! @natrevbioeng.bsky.social www.nature.com/articles/s44...
nature.com
Modelling and design of transcriptional enhancers - Nature Reviews Bioengineering
Enhancers are genomic elements critical for regulating gene expression. In this Review, the authors discuss how sequence-to-function models can be used to unravel the rules underlying enhancer activit...
15732
Reposted by Niklas Kempynck
Stein Aerts @steinaerts.bsky.social · 14/02/2025
This has been a fantastic adventure - to capture the genomic regulatory code underlying brain cell types (using deep learning models trained on chromatin accessibility), and then use these models to compare cell types between the bird and mammalian brain
44112
Niklas Kempynck @niklaskemp.bsky.social · 14/02/2025
Also, check out the two related articles from the @kaessmannlab.bsky.social and García-Moreno groups, and the expert perspective by @giacomogattoni.bsky.social and Maria Antonietta Tosches www.science.org/doi/10.1126/...!
science.org
Constrained roads to complex brains
Neural development and brain circuit evolution converged in birds and mammals
050
Niklas Kempynck @niklaskemp.bsky.social · 14/02/2025
Just very happy to have our paper out today! A big thanks to all our co-authors, and to Nikolai and @steinaerts.bsky.social for the teamwork over the past years. If you are interested in using our models for cross-species enhancer studies, check out crested.readthedocs.io/en/stable/mo... 🙂
35325