KatajistoLab

Helsingin yliopisto johtaa viittä uutta tutkimuksen huippuyksikköä | Helsingin yliopisto Suomen Akatemia on valinnut 11 uutta tutkimuksen huippuyksikköä ohjelmakaudelle 2026–2033. Niistä viittä johdetaan Helsingin yliopistosta, ja yhteensä yliopiston tutkijat ovat mukana kahdeksassa uudes...

Suomen Akatemia on valinnut 11 uutta tutkimuksen huippuyksikköä ohjelmakaudelle 2026–2033. Niistä viittä johdetaan Helsingin yliopistosta.

Yhteensä yliopiston tutkijat ovat mukana kahdeksassa uudessa huippuyksikössä.

www.helsinki.fi/fi/uutiset/y...

Still time today to sign up and submit an abstract for this excellent symposium

And read the thesis helda.helsinki.fi/items/67fd7e...

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Follow the live stream here tapahtumat.helsinki.fi/en-FI/page/6...

On Tue Oct 14th @simonsterson.bsky.social will defend his thesis Age-selective organellar metabolism in tissue stem cell function, at 1 pm in Biocenter 2 2041, Viikki. Excited to have Jared Rutter @rutterlab.bsky.social as the opponent 🎩⚔️ Welcome! @metastem.bsky.social @hilife-helsinki.bsky.social

Check out the symposium organized by our CoE, excited to have Marcia Haigis, @lydiafinley.bsky.social, Matthias Hebrok and Tom MacVicar over in Helsinki in November. Sign up by October 22nd 👇

Welcome to the Stem Cell Seminar next week Friday Oct 3rd at 9-11, ☕️🍪 at 8:30. Exciting science on embryo development, ECM, cancer and stem cells by Juha Kere and @johannaienglund.bsky.social labs. See you there! @hilife-helsinki.bsky.social @helsinki-biotech.bsky.social @stemmprogram.bsky.social

#CFM_MolCellAging: The third session will deal with the regulation of aging processes, with talks by
@pekka-katajisto.bsky.social  @metastem.bsky.social  @helsinki.fi and Salvador Aznar @irbbarcelona.org

  Registration: http://bit.ly/4kOyYch  

🤝With support of @caixaresearch.bsky.social

Pekka Katajisto @katajistolab.bsky.social introducing Nobel laureate Shinya Yamanaka who will talk about 2 of my favorite topics: sciences and marathons

@natmetabolism.nature.com

Also read the research briefing on our latest paper in @natmetabolism.nature.com

New Type of Intestinal Stem Cell Discovered, Offering Hope for Enhanced Regeneration and Chemotherapy Recovery | HiLIFE – Helsinki Institute of Life Science | University of Helsinki A team of researchers from the University of Helsinki has discovered a previously unknown type of intestinal stem cell, which supports intestinal regeneration through its metabolically distinct mitoch...

Also read the news item by Uni Helsinki, descibing possible future application of the findings during chemothrapy-induced damage www.helsinki.fi/en/hilife-he... 8/8 @helsinki-biotech.bsky.social

Congratulations to Simon @simonsterson.bsky.social, for fantastic persistence during the whole journey, and big thank you to all co-authors, @hienbui.bsky.social Arto Viitanen @hietakangaslab.bsky.social @pekka-katajisto.bsky.social and others @metastem.bsky.social @helsinki.fi 7/8

Our results demonstrate the existence of previously unknown asymmetric division and metabolic heterogeneity in the intestinal stem cell pool, which can’t be seen in the transcriptome. Further, we find that metabolic intervention can be used for replacement of specific defective cells. 6/8

aKG supplementation in vivo leads to renewal of Paneth cells, which in old animals reduces expression of the Wnt-antagonist Notum, and rescues recovery after 5-FU-induced damage to the level of young animals. 5/8

ISCs with old mitochondria have faster TCA-cycle turnover and higher amounts of aKG, which drives the bias towards the Paneth cell linage and increased Tet2-dependent 5-hydroxy methylation of cytosines in DNA. 4/8

These stem cells (ISC-mito-O) are better at forming organoids in vitro due to their ability to regenerate Paneth cells faster. 3/8

Using in vivo snap-tag labeling of mitochondrial age-classes, we found that the intestine contains a subset of stem cells that retain old mitochondria through asymmetric division. 2/8

Old mitochondria regulate niche renewal via α-ketoglutarate metabolism in stem cells - Nature Metabolism Andersson et al. show that intestinal stem cells enriched for old mitochondria are metabolically distinct and have enhanced ability to regenerate the epithelial niche.

Proudly presenting Simon’s @simonsterson.bsky.social‬ paper on asymmetric apportioning of old mitochondria biasing intestinal stem cells for the Paneth cell linage through aKG-dependent metabolism
@naturemetabolism.bsky.social www.nature.com/articles/s42... @helsinki.fi @metastem.bsky.social 🧵1/8

Thank you to the organizers of the fantastic meeting #CSMetabolites2025 Kivanc Birsoy @robzonculab.bsky.social and @cellpress.bsky.social editors Allyson Evans @kristabledsoe.bsky.social We had a fantastic time in Sitges, looking forward to this meeting happening again! @cellpressevents.bsky.social

Thank you Christian 😊

Congratulations Hien Bui who showed remarkable persistence in initiating, leading and finalizing the project. Thank you to everyone involved, especially second authors @simonsterson.bsky.social Agustin Sola Carvajal and all collaborators at @helsinki.fi i.fi @metastem.bsky.social and @ki.se. 9/9

In conclusion, we discovered a new role for peroxisomes in determination of cell fate of adult stem cells through their age-dependent segregation and spatially compartmentalized metabolism. The SNAP-PTS1 mouse will be a valuable tool for studying peroxisomal heterogeneity also in other tissues. 8/9

We found that sub-cellular compartmentalization of specific metabolic reactions determines cell fate as expression of G6PD specifically on the peroxisome membrane, but not in the cytosol or in the peroxisome matrix, boosted stemness through peroxisomal ether lipid synthesis. 7/9

To find the mechanism, we performed proteomics of old and young peroxisomes isolated by density centrifugation and single-organelle FACS and found the metabolic enzyme G6PD to be enriched on old peroxisomes. 6/9

Similarly, during in vivo ACD of epidermal stem cells, old peroxisomes were preferentially inherited by the daughter cell that remains attached to the basement membrane. 5/9

In in vitro ACD of basal mammary epithelial cells, daughter cells with old peroxisomes PO exhibited higher self-renewal and bi-potency than daughter cells with young peroxisomes PY, demonstrated by their ability to form organoids and create the luminal lineage to induce branching morphogenesis. 4/9

To study if this takes place in primary adult stem and progenitor cells, we generated a novel mouse model expressing the SNAP-PTS1 construct, allowing for temporal labelling of peroxisomes in vivo, and saw heterogeneity of peroxisome age in epithelial cells in the mammary gland and the skin. 3/9