Longitudinal study of liver disease progression in the PEX1-Gly844Asp mouse model of mild Zellweger Spectrum Disorder
Bibliographic record
Abstract
ABSTRACT Introduction Zellweger spectrum disorder (ZSD) is an autosomal recessive disorder caused by mutations in any of 13 PEX genes encoding proteins required for peroxisome assembly and function. Chronic liver disease is one of the major clinical manifestations in patients and impacts quality of life and survival. However, the pathophysiology of liver disease is ZSD remains largely unknown, and current interventions are limited. To further study the liver disease mechanism, we use the PEX1-Gly844Asp (G844D) mouse model for mild ZSD, which was previously shown to develop hepatomegaly and cholestasis, similar to ZSD patients. Methods The natural history of hepatopathy was broadly characterized in PEX1-G844D mice and littermate controls from 1 to 18 months of age using liver histology, electron microscopy, cultured hepatocytes and blood. Metabolite and mechanism analysis included liver functions, respiratory chain dynamics, lipidomics, peroxisome metabolites, gene and protein expression assays. Results PEX1-G844D mice featured liver disease progression from hepatomegaly (1 month) to cluster cell death (4 months), hepatosteatosis (6 months), inflammation (8 months), fibrosis, and hepatic cancer (12 and 15 months). Hepatocyte proliferation and reduced glycogen was observed across all ages. Measurement of peroxisomal functions showed defective peroxisomal import and secondary mitochondrial defects in cultured hepatocytes. In blood and liver, plasmalogens were decreased, and C26:0 lyso-phosphatidylcholine and C27 bile acid intermediates were elevated. In liver, we observed accumulation of triglycerides and cholesterol, and reduced membrane phospholipids and sphingolipids. In contrast, in serum we observed reduced triglycerides, cholesterol and membrane lipids. Gene expression profiles confirmed by immunoblotting supported reduced hepatic de novo lipogenesis, increased hepatic lipid uptake and oxidation, PPARα activation, and modulated glucose and glycogen metabolism. Liver X receptor agonist (T0901317) applied to cultured hepatocytes enhanced hepatic lipogenesis and lipid secretion, but aggravated steatosis. Conclusion Taken together, these results suggested the following mechanisms of hepatopathy progression. We propose that global peroxisome dysfunction (1) causes PPARα activation, leading to chronic hyperplasia and partially contributing to disrupted hepatic lipid homeostasis with hepatosteatosis, and (2) underlies chronic hypoglycemia, causing hypoinsulinemia and contributing to reduced hepatic lipogenesis and systemic lipid deficiency. Growth restriction in the mouse model and in ZSD patients could be attributable to systemic lipid deficiency. Our mechanistic delineation of the pathophysiology provides other additional novel potential therapeutic targets to halt liver disease in ZSD.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".