SAMHD1 controls nucleoside-based cancer therapeutics, deoxyguanosine toxicity, and inflammation

Moore, M. D.; Johnson, E.; Jacklin, C.; Johnson, S.; Green, O.; James, W. S.

doi:10.1101/2022.08.25.505278

Home/Archive/bioRxiv

bioRxiv · 10.1101/2022.08.25.505278

SAMHD1 controls nucleoside-based cancer therapeutics, deoxyguanosine toxicity, and inflammation

Moore, M. D.·Johnson, E.·Jacklin, C.·Johnson, S.·Green, O.·James, W. S.

View original source ↗Export metadata ↓

Abstract

SAMHD1 is a key regulator of dNTP metabolism, being activated by dGTP and converting dNTPs into their respective nucleosides. As a result, it plays a significant role in several distinct diseases. Not only is SAMHD1 a restriction factor for HIV-1 replication, which requires dNTPs for replication, but it is also required for genome stability, is mutated in multiple cancers, and loss of function mutations cause Acardi-Goutieres Syndrome, an early-onset inherited encephalopathy. In this paper we knock out the SAMHD1 gene in pluripotent stem cells, and show that it also affects nucleoside analogue sensitivity of dividing cells and deoxyguanosine toxicity in a cell cycle-independent manner. Comparing wild type and gene-edited macrophages, we also show that deoxyguanosine toxicity is associated with pro-inflammatory cell death, modifications in uric acid production and the formation of monosodium urate crystals within the macrophages. These novel features of the SAMHD1-/- phenotype provide unique insights into the aetiology of Acardi-Goutieres Syndrome, and have implications for certain chemotherapeutic agents.

Explore related subjects

pharmacology and toxicology Preprint

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Moore, M. D., Johnson, E., Jacklin, C., Johnson, S., Green, O., James, W. S.. 2022-08-27. SAMHD1 controls nucleoside-based cancer therapeutics, deoxyguanosine toxicity, and inflammation. https://doi.org/10.1101/2022.08.25.505278

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Lipid-ASO therapeutics exhibit differential tissue targeted delivery upon systemic or local CNS administration

Antisense oligonucleotides (ASOs) are a powerful therapeutic modality, but their full potential is hindered by pharmacokinetic properties that affect tissue and cellular delivery. Lipid conjugation is increasingly used to modulate ASO's biodistribution and promote extrahepatic activity, yet lipid dependent effects on in vivo functional delivery, particularly in the central nervous system (CNS), remain less explored. Here, we performed a side by side in vivo comparison of cholesterol, palmitic acid (C16:0), docosanoic acid (C22:0), and eicosapentaenoic acid (C20:5) conjugated to a fully phosphorothioated 3 10 3 LNA gapmer ASO targeting the Malat1 long non coding RNA. Lipid-ASO conjugates were administered systemically or locally in the brain of mice and evaluated for tissue level and cellular level distribution by imaging, qPCR and single-cell RNA sequencing, simultaneously annotating cell origin and global transcriptional changes within the cell. Following systemic administration in mice, lipid conjugation improved overall multi organ efficacy compared to unconjugated ASO, but with pronounced tissue specific differences. Single cell sequencing of liver and heart transcriptomes revealed lipid dependent cellular uptake patterns and transcriptional responses distinct from administration of unconjugated ASO. After intracerebroventricular administration, selected fatty acid conjugates enhanced silencing in deep brain regions such as the striatum, whereas cholesterol conjugation impaired functional delivery despite increased CNS retention. Light-sheet microscopy showed restricted parenchymal penetration of cholesterol ASOs compared with broader but heterogeneous distribution of palmitic acid conjugate. Together, these findings demonstrate that lipid identity critically determines ASO efficacy, productive cellular uptake, and regional CNS engagement, emphasizing the need for context specific lipid design in ASO therapeutic development.

pharmacology and toxicology↗

bioRxiv2026

Novel Dissymmetric Ionizable Lipid-Assembled Lipid Nanoparticles for Delivery of Ferroptosis-Related siRNA in Diabetic Treatment

Small interfering RNA (siRNA) enables precise post-transcriptional gene silencing for refractory diseases, yet its clinical translation remains limited by the lack of safe and efficient delivery vectors. Inspired by the dissymmetric alkyl chain architecture of natural membrane phospholipids, we designed and synthesized 34 novel ionizable lipids with dissymmetric hydrophobic tails and formulated them into lipid nanoparticles (LNPs). Through systematic physicochemical and biological assessments, we established clear structure-activity relationships and identified two lead LNPs (O14-LNP, H18a-LNP) with superior endosomal escape capacity, enhanced in vivo gene silencing potency, and favorable biosafety relative to the clinical benchmark MC3-LNP. In both streptozotocin-induced and spontaneous db/db type 2 diabetes (T2D) mouse models, lead LNPs delivering ferroptosis-related siRNAs effectively ameliorated glucose and lipid metabolic disorders, restored islet function, and alleviated hepatic steatosis. This study not only lays a theoretical foundation for the rational design of novel ionizable lipids, but also validates the therapeutic potential of siRNA therapy targeting ferroptosis, providing a versatile delivery platform and targeted therapeutic strategy for the treatment of T2D.

pharmacology and toxicology↗

bioRxiv2025

Conformational dynamics in the membrane interactions of bispecific targeted degrader therapeutics

Proteolysis targeting chimeras (PROTACs) offer vast new therapeutic opportunities, however their physicochemical properties are difficult to combine with optimal cell permeability and exposure at the target sites. We have systematically analyzed a dataset of more than 3500 PROTACs to investigate how the choice of ubiquitin E3 ligase ligands, linker design, and global molecular properties can be optimized to achieve the desired cell permeability and intracellular exposure. We find that conformational flexibility leads to environment-dependent shielding of polar functions and improved interactions with cell membranes, but that at the same time extended, linear conformations within the membrane are beneficial. Linker composition was a major factor in determining the folding propensity. Collectively, our results suggest that strategies to rationally design linkers and to shield polarity selectively within the protein-of-interest (POI) ligand and/or E3 ligand domains, rather than more extensive folding, may be beneficial in the design of permeable and effective PROTACs.

pharmacology and toxicology↗