Joachim Nielsen

Low-dose lithium, oestrogen deficiency and the sarcoplasmic reticulum: Are they connected
onlinelibrary.wiley.com/share/author...

Low-dose lithium supplementation promotes musculoskeletal and metabolic health in ovariectomized female mice physoc.onlinelibrary.wiley.com/share/IMJBJH...

A network-based atlas of human skeletal muscle aging Skeletal muscle metabolic and physical capacities are influenced by both genetics and load status and decline with age. Recent advances in sequencing have detailed cell types at unprecedented detail; ...

A network-based atlas of human skeletal muscle aging
www.medrxiv.org/content/10.6...

Our new project unveiling an integrative single-fiber framework that connect multi-omic cellular heterogeneity to molecular function in ICU-related muscle wasting! Congratulations to all authors especially Alexandra who led the whole project! Thank you to @lundbeckfonden.bsky.social for the support

Exofacial Epitope–Specific Antibodies Detect GLUT4 Translocation in Adult Human, Rat, and Mouse Skeletal Muscle Skeletal muscle glucose transporter 4 (GLUT4) translocation to the plasma membrane determines glucose uptake in response to insulin and exercise and is dis

Our latest work showing that GLUT4 exofacial antibodies can measure translocation in humans and rodent skeletal muscle fibers and is impaired in TBC1D4 KO rats despite rescued GLUT4 expression. Congrats Kaspar and co-authors. DM me for open access version:
diabetesjournals.org/diabetes/art...

Dynamic balance of myoplasmic energetics, redox state and protons in a fast‐twitch oxidative glycolytic skeletal muscle fibre Abstract figure legend We have developed a computational model of energy metabolism in fast-twitch oxidative glycolytic muscle fibres. The model considers thermodynamically constrained enzyme kinetic....

doi.org/10.1113/JP28...

Quantification of muscle glycogen distribution in Pompe disease using 7 Tesla 13C NMR spectroscopy Background Late-onset Pompe disease has a characteristic pattern of fat replacement and wasting of especially axial and hamstring muscles. This characteristic pattern of muscle degeneration is still t...

Beha GH, Stemmerik MG, Boer VO, et al.
Quantification of muscle glycogen distribution in Pompe disease using 7 Tesla 13C NMR spectroscopy
jnnp.bmj.com/content/97/3...

Huge thanks to Anders Aagaard Hansen @andersaagaard.bsky.social for pushing this project forward, Jacob Egebjerg for model development, and our co-authors for samples, validation, and biochemical analyses.
#MyoBlue #OpenScience

Crucially, the model performs well across low to high glycogen levels and closely matches biochemical glycogen measurements from chemical extraction.

bioRxiv: doi.org/10.64898/202....
Model & code: github.com/JoachimNiels...
Raw data: doi.org/10.5281/zeno...
(Open access & reusable)

The model was trained on 859 EM images and automatically classifies where glycogen particles are located in muscle fibers:
• within myofibrils
• between myofibrils
• subsarcolemmal (for peripheral images)

We are ready to scale up glycogen analysis using electron microscopy.
By applying a new AI-based image analysis pipeline, workload for 50 samples was reduced from ~600 hours to ~20 hours. This moves us beyond small-scale TEM studies.
Details below 👇

faseb.onlinelibrary.wiley.com/share/KKBJBR...

For ~century, we’ve asked: why do proliferating cells ferment glucose even when O2 is around? I’m thrilled to share our latest work @natmetabolism.nature.com, led by @thebiokimist.bsky.social. By leveraging conditional essentiality in HPLM, we propose a provocative new answer to this classic Q. 🧵

Mitochondrial contact site and cristae organizing system promotes modular assembly of cytochrome c oxidase Colina-Tenorio et al. show that MICOS interacts with the Cox1 and Cox3 assembly modules and facilitates respiratory complex IV biogenesis. By recruiting assembly factors and the mitochondrial multifun...

Mitochondrial contact site and cristae organizing system promotes modular assembly of cytochrome c oxidase: Cell Reports www.cell.com/cell-reports...

📄 New preprint

Using deep physiological and molecular phenotyping in individuals carrying a diabetogenic mtDNA mutation, we probe whether, which, and how mitochondrial defects drive insulin resistance in humans.

👇 Link in first comment

#Physiology #Diabetes #Mitochondria #Metabolism

Acute effects of resistance exercise on skeletal muscle glycogen depletion: A systematic review and meta‐analysis To compile and statistically summarize quantitative evidence on the acute effects of resistance training sessions on muscle glycogen concentration, a systematic search was conducted on Pubmed, Web of...

Acute effects of resistance exercise on skeletal muscle glycogen depletion: A systematic review and meta-analysis
physoc.onlinelibrary.wiley.com/doi/10.14814...

Self-renewal of neuronal mitochondria through asymmetric division Mitochondrial ATP production is essential for life. Mitochondrial function depends on the spatio-temporal coordination of nuclear and mitochondrial genome expression, yet how this coordination occurs ...

⚡️Mitochondria make ATP, the energy that powers life. But in neurons, with axons up to a meter long, how do these tiny power plants stay functional in the right places? We went looking. 1/n www.biorxiv.org/content/10.6...

Neuromodulatory control of energy reserves in dopaminergic neurons | PNAS The brain is a metabolically vulnerable organ as neurons have both high resting metabolic rates and the need for local rapid conversion of carbon s...

"We find that when glycogen stores are present, they provide remarkable resilience to dopamine nerve terminal function under extreme hypometabolic conditions, but ... impairment of access to glycogen, makes them hypersensitive to fuel deprivation."
www.pnas.org/doi/suppl/10...

This ‘fundamental’ study uncovers how directing pyruvate into mitochondria can shrink cells by shifting their metabolism away from building amino acids and proteins.
buff.ly/hFHjKy9

Super happy to share our latest study on muscle remodeling in human cachexia in patients with lung cancer: www.biorxiv.org/content/10.1...

Finally, someone has solved a real problem with AI! No more having to take a paper in the format for a journal that rejected you, and reformat it for a new journal. Well done!! formatmypaper.com

First post on Blue Sky

New pre-print!

Does muscle remember disuse muscle wasting?

Our new study shows skeletal muscle retains a molecular memory of disuse!

Young muscle shows transcriptional resilience to repeated atrophy.

Aged muscle shows exaggerated susceptibility.

doi.org/10.1101/2025...

Enabling options for review: from training and transparency to author-centered AI tools - openRxiv Peer review is widely viewed as a critical aspect of biomedical communication. Ideally, it provides authors with feedback so they can improve manuscripts and gives readers, particularly nonspecialists...

Excited to launch an openRxiv partnership with the scientist-run AI review service qed (@qedscience.bsky.social), the brainchild of @odedrechavi.bsky.social 1/n

openrxiv.org/enabling-rev...

IT'S HAPPENING! 💥 I'm psyched to launch the collaboration between @qedscience.bsky.social & @openrxiv.bsky.social @biorxivpreprint.bsky.social! Preprint + q.e.d = your science is out there, and anyone can appreciate it. Let's care about making discoveries, and not on “getting published” (1/3) 👇

NSAID ingestion augments training‐induced muscle hypertrophy and differentially affects muscle mRNA expression, but not strength gains, in trained men Abstract figure legend Schematic outlining the impact of NSAID ingestion on resistance exercise training-induced changes in muscle morphology, function and gene networks relative to placebo ingestion...

Hopefully of interest to scientists and exercise practitioners with and interest in muscle mass and functional gains in human volunteers. doi.org/10.1113/JP28...

@jphysiol.bsky.social

Principles of protein abundance regulation across single cells in a mammalian tissue Protein synthesis and clearance are major regulatory steps of gene expression, but their in vivo regulatory roles across the cells comprising complex tissues remains unexplored. Here, we systematicall...

This article is a homecoming for me.

As a PhD student, I focused on the growth-rate transcriptional regulation in yeast.

Now, ~ 20 years later, we report protein regulation scaling with the growth rates of single cells in mammalian tissues.

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

RACMEM Debate: Is Human Energy Expenditure Constrained? | Javier Gonzalez Is human energy expenditure constrained? This hypothesis was proposed by Herman Pontzer, and has received widespread interest with coverage from mainstream media, podcasts, and even the RI Christmas ...

Is Human Energy Expenditure Constrained? I recently debated Herman Pontzer on this topic in Shenzhen, China.

My slides can be viewed here:

www.linkedin.com/posts/javier...

Manuscript now accepted! 🥳 @steffendanielle.bsky.social @valerioizzi.bsky.social @abigailmackey1.bsky.social @ismcopenhagen.bsky.social

Spatially distinct ECM-producing fibroblasts and myonuclei orchestrate early adaptation to mechanical loading in the human muscle-tendon unit

The Expanding Clinical and Genetic Spectrum of Muscle Glycogen Storage Disease 0, (GSD0B) Glycogen storage disorders are a group of genetic disorders affecting glucose homeostasis in the body. Muscular glycogen stores are essential for liberating glucose for energy supply during bursts of...

The Expanding Clinical and Genetic Spectrum of Muscle Glycogen Storage Disease 0, (GSD0B) - Donoghue - 2025 - American Journal of Medical Genetics Part A - Wiley Online Library onlinelibrary.wiley.com/doi/10.1002/...

Phosphorylation of RYR1 at Ser2902 decreases Ca2+ leak in skeletal muscle and susceptibility to malignant hyperthermia and heat stroke Reducing Ca2+ leak through mutant RYR1 prevents pathological heat production in skeletal muscle.

New #scisignal paper: Phosphorylation of RYR1 at Ser2902 decreases Ca2+ leak in skeletal muscle and susceptibility to malignant hyperthermia and heat stroke. #Myoblue tinyurl.com/bddss3j6

Cardiolipin dynamics promote membrane remodeling by mitochondrial OPA1 - Nature Communications This study reveals how cardiolipin governs mitochondrial morphology by modulating the activity of human OPA1 and how its replacement by monolyso-cardiolipin, as observed in Barth syndrome, impacts mitochondrial membrane-shaping mechanisms.

Excited to share that our paper on mitochondrial cardiolipin dynamics is published in @natcomms.nature.com today! We provide molecular explanations for unique aspects of mitochondrial morphology and the mechanisms underlying cardiolipin-related Barth Syndrome.
www.nature.com/articles/s41...