Alanine catabolism of Paneth cells maintains intestinal stem cell function during dietary restriction
Bibliographic record
Abstract
Abstract Background and aims Paneth cell niche promotes the function of intestinal stem cells (ISCs) during reduced food intake, but how ISC activity can be boosted when availability of resources is simultaneously reduced remains unknown. Methods Mice were subjected to dietary restriction (DR) and ad libitum (AL) dietary regime. FACS-sorted DR and AL Paneth cells and Lgr5+ stem cells were co-cultured, and organoid formation supportive capacity of Paneth cells was assessed. The role of Gpt2 – a Paneth cell specific mitochondrial alanine transaminase, was investigated by targeting pharmacologically and genetically in the intestinal organoids. By using U- 13 C labelled Alanine, an intercellular metabolic exchange assay was developed – and a conversion and transport of lactate from Paneth cells to stem cells, was followed by metabolomics. The in vivo role of Gpt2 was investigated in a conditional knock out mouse model. Results We discovered that an increase in ISC function upon dietary restriction (DR) or DR mimicking condition, is dependent on Gpt2 in Paneth cells. Metabolic tracing of alanine directly showed DR boosts Paneth cell alanine catabolism, increasing lactate production via gluconeogenesis. Alanine derived lactate is shuttled from Paneth cells to neighboring stem cells, promoting TCA cycle and enhancing the ISC function during DR. Correspondingly, pharmacologic inhibition i n vitro and genetic targeting of Gpt2 in vivo abolished the DR induced capacity of Paneth cells to support ISC function. Conclusions Our results unravel dynamic intercellular metabolic cooperation in tissue adaptation, where Paneth cells upregulated Gpt2 catabolize increased amount of alanine to generate lactate as a transferable energy source, and to augment stem cell functions under DR.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".