Mansson Welinder, R. | Search bioRxiv

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↗

bioRxiv2025

Whole genome sequencing with AVITI and NovaSeq X Plus reveals comparable performance with contextual biases

Element Biosciences avidity sequencing has emerged as a competing technology to Illuminas short read sequencing platform. Prior benchmarks of avidity sequencing have not included the latest Illumina NovaSeq X/X Plus instruments with XLEAP chemistry. Here, we have run PCR-free whole genome sequencing on four human tumor cell lines using both Illumina NovaSeq X Plus and Element AVITI instruments. AVITI showed low duplication rates and reported higher base qualities, the latter contributed to improved mapping confidence and fewer spurious variant candidates. Both platforms were found to be highly comparable when benchmarking variant calling, with AVITI only providing a minor improvement on INDELs at lower coverages. Stratifying by genomic context revealed further differences, where AVITI genome coverage and variant calls were superior in high GC regions while being inferior in GC homopolymers. Error rate analysis highlighted further differences between the platforms, in particular AVITI in some instances displayed an increased error rate on read 2 related to short fragments. AVITI error rate was also found to be more stable downstream of repetitive regions, except for GC homopolymers. We further found that AVITI sequencing was sensitive to G-quadruplex motifs. Overall, despite these identified differences, both platforms performed highly comparable for variant analysis.

genomics↗