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David Walzik

@davidwalzik.bsky.social
66 followers 124 following 50 posts

PhD student at TU Dortmund University | Medical student University of Cologne | Studying the molecular impact of exercise on immune cells | Sports enthusiast 🚴🏽🏋🏽🏃🏽

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David Walzik @davidwalzik.bsky.social · 05/01/2026
@niklasjoisten.bsky.social @sebproschinger.bsky.social @50823zimmer.bsky.social Looking forward to 2026! Full article: doi.org/10.1038/s414...
doi.org
Acute exercise rewires the proteomic landscape of human immune cells - Nature Communications
Exercise has considerable health benefit, including modulation of the immune system. Here the authors compare the molecular make-up of peripheral blood immune cells at resting state and upon a single ...
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David Walzik @davidwalzik.bsky.social · 05/01/2026
Many thanks to all our collaborators from @kingscollegelondon.bsky.social, @dkfz.bsky.social, IfADo - Leibniz-Institut für Arbeitsforschung an der TU Dortmund, German Sport University, and our team @tu-dortmund.de. This wouldn’t have been possible without the input from many different sides!
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David Walzik @davidwalzik.bsky.social · 05/01/2026
This opens exciting new avenues on exercise as a crucial driver of immunological competence and the "trainability" of our immune system, which has huge implications for disease prevention across different populations.
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David Walzik @davidwalzik.bsky.social · 05/01/2026
Using machine learning-based prediction models we were able to identify an immunoproteomic signature composed of 20 proteins that is highly predictive of cardiorespiratory fitness.
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David Walzik @davidwalzik.bsky.social · 05/01/2026
3. What I am most excited about, however, is what we discovered when turning our attention to the baseline data. Leveraging the high proteomic resolution and the repeated baseline measurements, we wondered whether we could learn anything about long-term training effects and immunological fitness.
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David Walzik @davidwalzik.bsky.social · 05/01/2026
2. These changes were more pronounced after high-intensity interval exercise (HIIE) compared to time- and energy-matched moderate-intensity continuous exercise (MICE) and occurred despite similar changes in immune cell mobilisation and redistribution between the two exercise conditions.
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David Walzik @davidwalzik.bsky.social · 05/01/2026
1. Using Gene Ontology analyses we observed that acute exercise rewires the immune cell proteome towards proteins involved in immune effector functions necessary for immunological defense and anticancer immunity.
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David Walzik @davidwalzik.bsky.social · 05/01/2026
We thus set out to tackle a simple but highly relevant question: Does a single bout of exercise alter immune cell proteostasis in a biologically meaningful manner and if so, is this process dependent on exercise intensity? Here is what we found:
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David Walzik @davidwalzik.bsky.social · 05/01/2026
The positive effects of exercise are well described on an epidemiological level, but mechanistic studies on the molecular underpinnings remain largely elusive.
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David Walzik @davidwalzik.bsky.social · 05/01/2026
As we grow older our immune system deteriorates, which is reflected by higher infection rates and cancer incidence in the elderly. Recent studies indicate that more youthful immune systems are linked to higher survival and that exercise plays a crucial role in keeping our immune system "fit".
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David Walzik @davidwalzik.bsky.social · 05/01/2026
Super happy to see the last paper of my PhD published in @natureportfolio.nature.com journal Nature Communications! Here is a graphical summary and a short thread of our findings.
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Proceedings of the National Academy of Sciences @pnas.org · 14/07/2025
One of the most-viewed PNAS articles in the last week is “Antioxidants prevent health-promoting effects of physical exercise in humans.” Explore the article here: www.pnas.org/doi/10.1073/... For more trending articles, visit ow.ly/Me2U50SkLRZ.
Mitohormesis links physical exercise and subsequent formation of reactive oxygen species to insulin sensitivity and antioxidant defense.
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Nature Metabolism @natmetabolism.nature.com · 18/04/2025
ICYMI:
bit.ly
NK cell-derived IFNγ mobilizes free fatty acids from adipose tissue to promote early B cell activation during viral infection
Nature Metabolism, Published online: 11 April 2025; doi:10.1038/s42255-025-01273-2Krapić, Kavazović and colleagues dissect the mechanism by which natural killer cells drive adipose tissue remodelling during viral infection, thus fuelling antiviral immune responses.
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Deutsche Forschungsgemeinschaft @dfg.de · 17/04/2025
PhD candidates and postdocs of all disciplines: Would you like to lead an independent junior research group? In our online talk you will get first-hand information about the aims of our Emmy Noether Programme, its eligibility requirements and more. Questions welcome! ➡️ www.dfg.de/en/research-...
PROSPECTS DFG Research Career Series: Emmy Noether Programme (in English) - 28/04/2025 - 1:15-2:45 p.m. CET
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Nature Metabolism @natmetabolism.nature.com · 14/04/2025
ICYMI:
bit.ly
Pre-fertilization-origin preservation of brown fat-mediated energy expenditure in humans
Nature Metabolism, Published online: 07 April 2025; doi:10.1038/s42255-025-01249-2In humans, conception during cold seasons is shown to exhibit higher brown adipose tissue activity and adaptive thermogenesis, and lower body mass index and visceral fat accumulation in the offspring.
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Daniel Drucker @danieljdrucker.bsky.social · 14/04/2025
The exerkine meteorin Metrnl is a potential therapeutic target for preserving human beta cell function and survival in type 1 #diabetes @diabetologiajnl.bsky.social link.springer.com/article/10.1...
link.springer.com
Exercise-induced meteorin-like protein protects human pancreatic beta cells from cytokine-induced apoptosis - Diabetologia
Aims/hypothesis Inflammation-driven pancreatic beta cell death is a hallmark of type 1 diabetes progression. We have previously shown that serum obtained from individuals after high-intensity interval...
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eLife @elife.bsky.social · 13/04/2025
Fruit flies demonstrate a mechanism that immune cells can use to control the availability of nutrients when fighting infections. buff.ly/NXOfE4a
buff.ly
Energizing immune cells
Experiments in fruit flies reveal a mechanism that immune cells can use to control the availability of nutrients when fighting infections.
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Margot Finn @eicathomefinn.bsky.social · 09/04/2025
'Bluesky has overtaken its flailing rival X in hosting posts related to new academic research, indicating the platform is fast becoming the go-to place for scholars to share their work.'
timeshighereducation.com
X’s dominance ‘over’ as Bluesky becomes new hub for research
Data indicates more scholars turning to alternative social media site to post about their work after Elon Musk’s Twitter takeover
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Niklas Joisten @niklasjoisten.bsky.social · 04/04/2025
Check out our new paper now out in Acta Physiologica on the tryptophan metabolite 3-HAA in the aging and exercise context 👇 @50823zimmer.bsky.social @davidwalzik.bsky.social onlinelibrary.wiley.com/doi/full/10....
onlinelibrary.wiley.com
Exercise training restores longevity‐associated tryptophan metabolite 3‐hydroxyanthranilic acid levels in middle‐aged adults
Aim Recent pre-clinical evidence suggests that the tryptophan metabolite 3-hydroxyanthranilic acid (3-HAA) and the related enzyme activity along the kynurenine metabolic pathway (KP) are associated ...
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Nature Portfolio @natureportfolio.nature.com · 01/03/2025
A study in Nature Medicine provides a comprehensive map of the contributions of environment and genetics to mortality and incidence of common age-related diseases, suggesting that the exposome shapes distinct patterns of disease and mortality risk. #Medsky 🧪
go.nature.com
Integrating the environmental and genetic architectures of aging and mortality - Nature Medicine
Based on a systematic analysis of environmental exposures associated with aging and mortality in the UK Biobank, the relative contributions of such exposures and genetic risk for mortality and a range of age-related diseases were compared, highlighting the potential beneficial effects of environment-focused interventions.
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Eric Topol @erictopol.bsky.social · 26/02/2025
Protein organ clocks, as assessed in over 6,000 people (~4,000 plasma proteins, 8 organs) with 20-year follow-up are predictive for over 30 age-related diseases www.thelancet.com/journals/lan...
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Eric Topol @erictopol.bsky.social · 25/02/2025
Peto's Paradox—that cancer does not increase with body size of mammals—was wrong. A new, comprehensive study of 263 species documents higher cancer prevalence with increasing body mass. Some large animals (e.g. elephants) have some built-in genetic adaptations www.pnas.org/doi/10.1073/... @pnas.org
pnas.org
No evidence for Peto’s paradox in terrestrial vertebrates | PNAS
Larger, longer-lived species are expected to have a higher cancer prevalence compared to smaller, shorter-lived species owing to the greater number...
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Thibaux Van der Stede @thibauxvanderstede.bsky.social · 19/02/2025
A deep dive into the heterogeneity of human muscle fibers using transcriptomics and proteomics, now online @naturecomms.bsky.social. This was an amazing collaboration between our team @wimderave.bsky.social and the team @adeshmukh.bsky.social www.nature.com/articles/s41...
nature.com
Human skeletal muscle fiber heterogeneity beyond myosin heavy chains - Nature Communications
Moreno-Justicia and colleagues report transcriptomic and proteomic pipelines to explore heterogeneity within human skeletal muscle fibers, identifying sources of fiber heterogeneity in healthy individ...
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David Walzik @davidwalzik.bsky.social · 18/02/2025
Pretty cool!
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Thibaux Van der Stede @thibauxvanderstede.bsky.social · 07/02/2025
Cellular crosstalk in skeletal muscle? A surprising role for mast cells? Histamine as a signal transducer during exercise? Check out the story in @cp-cellmetabolism.bsky.social 🧵 @wimderave.bsky.social, @ugent-fge.bsky.social, @fwovlaanderen.bsky.social www.sciencedirect.com/science/arti...
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Matthew Alexander, PhD @mattmuscleguy.bsky.social · 06/02/2025
New #Cell_Metabolism paper: Cellular deconstruction of the human skeletal muscle microenvironment identifies an exercise-induced histaminergic crosstalk. #MyoBlue tinyurl.com/ymc5ha3w
tinyurl.com
Cellular deconstruction of the human skeletal muscle microenvironment identifies an exercise-induced histaminergic crosstalk
Van der Stede et al. identified a role for mononuclear cells in the skeletal muscle microenvironment to steer the response to exercise. Mast cells locally secrete histamine during exercise, triggering...
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David Walzik @davidwalzik.bsky.social · 05/02/2025
As always this project wouldn’t have been possible without the support and input of many different people. Thanks a lot to all co-authors! (12/12) @50823zimmer.bsky.social @niklasjoisten.bsky.social
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David Walzik @davidwalzik.bsky.social · 05/02/2025
All our generated datasets and the proteomics raw data files are publicly available with this preprint. To facilitate data mining with respect to this and upcoming projects, we are currently finalising an interactive website, which will be published alongside the article once it is accepted. (11/12)
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David Walzik @davidwalzik.bsky.social · 05/02/2025
Our data also supports the WHO physical activity guidelines, which highlight exercise intensity as a relevant factor to maintain health: doi.org/10.1136/bjsp.... (10/12)
doi.org
World Health Organization 2020 guidelines on physical activity and sedentary behaviour
Objectives To describe new WHO 2020 guidelines on physical activity and sedentary behaviour. Methods The guidelines were developed in accordance with WHO protocols. An expert Guideline Development Gr...
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David Walzik @davidwalzik.bsky.social · 05/02/2025
This is in line with epidemiological studies showing reduced disease risk and improved disease course in people performing high levels of physical activity (e.g., doi.org/10.1136/bjsp... and doi.org/10.1007/s402...). (9/12)
doi.org
Physical activity and risk of infection, severity and mortality of COVID-19: a systematic review and non-linear dose–response meta-analysis of data from 1 853 610 adults
Objective To quantify the association between physical activity and risk of SARS-CoV-2 infection, COVID-19-associated hospitalisation, severe illness and death due to COVID-19 in adults. Design A sys...
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David Walzik @davidwalzik.bsky.social · 05/02/2025
Overall, our results suggest that repetitive exposure to acute exercise bouts, especially HIIE, reshapes the proteome of PBMCs. As indicated by our VO2peak prediction, accumulation of these acute effects might culminate in immunological exercise adaption over time. (8/12)
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David Walzik @davidwalzik.bsky.social · 05/02/2025
We also leveraged our dataset to predict cardiorespiratory fitness and identified an immunoproteomic signature that was associated with VO2peak. Interestingly, several proteins associated with energy metabolism and immune function had a strong impact on VO2peak prediction. (7/12)
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David Walzik @davidwalzik.bsky.social · 05/02/2025
Some of these cell functions were shared across all clusters, which suggests that these "core immune effector functions" are regulated irrespective of the underlying protein kinetic. In contrast, others were unique to a specific protein cluster. (6/12)
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David Walzik @davidwalzik.bsky.social · 05/02/2025
We then carried on by unraveling the proteomic alterations induced by HIIE. Making use of soft clustering and gene ontology analyses we found 4 distinct protein clusters that contained numerous proteins associated with immune effector functions. (5/12)
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David Walzik @davidwalzik.bsky.social · 05/02/2025
These changes occurred despite identical immune cell mobilisation patterns between HIIE and MICE, suggesting that HIIE reshapes the proteome of PBMCs in a more pronounced fashion and that this process is independent of immune cell mobilisation. (4/12)
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David Walzik @davidwalzik.bsky.social · 05/02/2025
This is crucial considering that exercise-induced changes in PBMC composition might impact proteomic results. Interestingly, we observed >1,300 changes in the proteome of PBMCs after HIIE and only 64 changes in response to MICE. (3/12)
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David Walzik @davidwalzik.bsky.social · 05/02/2025
In this work we performed flow cytometry-based immune cell phenotyping and mass spectrometry-based proteomics to consider both, changes in peripheral immune cell counts and alterations in the PBMC proteome. (2/12)
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David Walzik @davidwalzik.bsky.social · 05/02/2025
Happy to share our new preprint, where we investigate the impact of acute exercise on the proteome of immune cell! Comparing high-intensity interval exercise (HIIE) and moderate-intensity continuous exercise (MICE), we found numerous proteins that were differentially expressed in PBMCs. (1/12)
medrxiv.org
Acute exercise rewires the proteomic landscape of human immune cells
Exercise-driven alterations of the immune system are a key mechanism in the prevention and treatment of various diseases. Here, we performed mass spectrometry-based proteomics analysis on peripheral b...
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Nature Metabolism @natmetabolism.nature.com · 29/01/2025
✨New issue!✨ Check out the latest in #metabolism research from across all disciplines 🧫🐭👥 Read about #Obesity, #Diabetes, #Epidemiology, #Myokines, #Cancer, #Aging - and many more topics! www.nature.com/natmetab/vol...
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Eric Topol @erictopol.bsky.social · 24/01/2025
Welcome immigrants from X interested in science to the friendlier skies of @bsky.app, as documented by a new @nature.com survey (but you already knew that 😉) "Bluesky is much better for science. There is much less toxicity, misinformation, and distractions." www.nature.com/articles/d41...
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Parham Eshtehardi MD @cardioobdoc.bsky.social · 19/01/2025
#CardioSky #MedSky community, I am reposting this because posts are still being “liked”. Pls “repost” if you like to share with others.
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Nature Portfolio @natureportfolio.nature.com · 14/01/2025
We have a feeling you'll be interested in this one. Nature is keen to find out how scientists are using Bluesky and whether it has become their go-to social-media platform. Take the survey! 🧪
go.nature.com
Has Bluesky replaced X for scientists? Take Nature’s poll
The research community has flocked to the social-media platform Bluesky. Tell us about your experience.
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Altmetric @altmetric.com · 03/12/2024
There are already many articles for which there is more attention on Bluesky than on other comparable micro-blogging sites, meaning the academic community and the general public have clearly adopted Bluesky as one of its core places to disseminate and discuss new research. A Place of Joy.
‘A place of joy’: why scientists are joining the rush to Bluesky
Researchers say the social-media platform — an alternative to X — offers more control over the content they see and the people they engage with.: https://www.nature.com/articles/d41586-024-03784-6
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David Walzik @davidwalzik.bsky.social · 04/12/2024
Thanks also to Anna Worthmann and team for performing intracellular metabolomics, to Sebastian Gehlert and team for doing Western Blots, to Bevital AS for performing serum metabolomics, and of course to all other people involved for giving great input along the way! (13/13)
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David Walzik @davidwalzik.bsky.social · 04/12/2024
As always this project would not have been possible without the help of numerous collaborators. A special thanks to @50823zimmer.bsky.social , Alan Metcalfe and @niklasjoisten.bsky.social who planned and conducted the trials and to Alexander Schenk, who performed hundreds of PCRs. (12/13)
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David Walzik @davidwalzik.bsky.social · 04/12/2024
Our results prove that acute exercise rearranges NAD⁺ metabolism of PBMCs and open promising research avenues on the immunometabolic underpinnings of enhanced immune effector function associated with acute exercise. (11/13)
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David Walzik @davidwalzik.bsky.social · 04/12/2024
Given that nicotinamide crosses cell membranes via diffusion, these results suggest enhanced biosynthesis of NAD⁺ via incorporation of nicotinamide in response to acute exercise in PBMCs. (10/13)
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David Walzik @davidwalzik.bsky.social · 04/12/2024
In trial 2, we confirmed the central role of NAMPT in the acute response to exercise on a gene expression level and showed that serum levels of the NAD⁺ precursor nicotinamide decrease during acute exercise, while intracellular NAD⁺ levels increase. (9/13)
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David Walzik @davidwalzik.bsky.social · 04/12/2024
Interestingly, acute exercise led to a profound increase in gene expression and protein abundance of NAMPT, the core enzyme of NAD⁺ salvage pathway. On a protein level similar effects were visible for NMNAT1, a further NAD⁺ salvage pathway enzyme. (8/13)
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David Walzik @davidwalzik.bsky.social · 04/12/2024
In trial 1, acute exercise increased gene expression of NAD⁺ metabolism enzymes in PBMCs, with only minor differences between high intensity and moderate intensity exercise. Differences between males and females were also negligible. (7/13)
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