Deficiency of Deoxyguanosine Kinase Links Purine Metabolism to Activation of Innate Immunity and Lipid Accumulation in Liver Cells

Overview

This study investigates the role of deoxyguanosine kinase (DGUOK) deficiency in hepatic steatosis and inflammation, revealing that acute DGUOK depletion activates innate immune signaling and lipid accumulation independent of mitochondrial DNA depletion.

Background

Mitochondrial DNA depletion syndromes (MDS) are characterized by impaired mitochondrial nucleotide homeostasis and can lead to severe liver dysfunction. DGUOK is crucial for mitochondrial purine salvage, and its deficiency is associated with hepatic steatosis and inflammation, even when mtDNA levels are preserved.

Data Highlights

Acute DGUOK depletion induced a 2.9-fold increase in intracellular lipid droplet accumulation and a 40% reduction in global DNA methylation.

Key Findings

• Acute DGUOK deficiency activates a type I interferon transcriptional program.
• Despite preserved mtDNA copy number, lipid accumulation occurs in DGUOK-deficient cells.
• Bulk RNA sequencing shows induction of human endogenous retroviruses (HERVs) and interferon-stimulated genes (ISGs).
• Purine imbalance leads to hypomethylation of CpG-rich regions within ISG promoters.
• Exogenous 2′-deoxyadenosine treatment mimics DGUOK deficiency effects on lipid accumulation and immune activation.

Clinical Implications

The findings highlight the importance of mitochondrial purine metabolism in regulating hepatic immune responses and lipid homeostasis.

Conclusion

This study links purine metabolism to innate immune activation and lipid accumulation in liver cells.

Related Resources & Content

1. Deoxyguanosine kinase deficiency: natural history and liver transplant outcome - PubMed
2. Deoxyguanosine Kinase Deficiency - GeneReviews® - NCBI Bookshelf
3. EASL Clinical Practice Guidelines on liver transplantation - Journal of Hepatology
4. EASL-EASD-EASO Clinical Practice Guidelines on the management of metabolic dysfunction-associated steatotic liver disease (MASLD)
5. The ASCO Post — MTH1 Inhibition Blocks Sanitation of Deoxyribonucleotide Triphosphate Pool and Causes Cancer Cell Death
6. Infection — The Involvement of the Kynurenine Pathway in Neuropathogenesis Associated with COVID-19
7. The ASCO Post — MTH1 Inhibition Blocks Sanitation of Deoxyribonucleotide Triphosphate Pool and Causes Cancer Cell Death
8. Acta Neuropathologica — The Role of DTYMK in Maintaining Genome Stability and Neuronal Viability
9. Deoxyguanosine Kinase Deficiency - GeneReviews® - NCBI Bookshelf
10. EASL-EASD-EASO Clinical Practice Guidelines on the management of metabolic dysfunction-associated steatotic liver disease (MASLD)
11. EASL Clinical Practice Guidelines on liver transplantation - Journal of Hepatology
12. Deoxyguanosine kinase deficiency: natural history and liver transplant outcome - PubMed
13. Gene therapy prevents hepatic mitochondrial dysfunction in murine deoxyguanosine kinase deficiency - ScienceDirect
14. The crucial roles and research advances of cGAS‑STING pathway in liver diseases - PMC