Unveiling Liver Micro-Distribution: NanoSIMS Imaging Reveals Critical Intracellular Distribution of Chemically...

Area of Science:

• Pharmacology
• Biotechnology
• Analytical Chemistry

Background:

• Antisense oligonucleotides (ASOs) are promising therapeutics, but their effectiveness and safety depend on tissue distribution and cellular uptake.
• Understanding ASO intracellular localization is vital for optimizing drug delivery and therapeutic outcomes.

Purpose of the Study:

• To investigate the intracellular distribution of chemically modified ASOs in liver tissue using high-resolution nanoscale secondary ion mass spectrometry (NanoSIMS) imaging.
• To correlate ASO chemical modifications with their subcellular localization and biodistribution patterns.

Main Methods:

• Utilized nanoscale secondary ion mass spectrometry (NanoSIMS) imaging for ultra-high resolution visualization of ASO distribution in liver tissue.
• Combined NanoSIMS with electron microscopy to analyze ASO localization within cellular compartments.

Main Results:

• Fully phosphorothioated ASOs accumulated in vesicular structures near nonparenchymal cells, such as Kupffer cells.
• Partially phosphorothioated ASOs showed a uniform distribution throughout the liver.
• Different chemical modifications led to distinct intracellular distribution patterns, even with similar overall liver concentrations.

Conclusions:

• Subcellular distribution is a critical factor in ASO drug discovery and development.
• NanoSIMS imaging is a powerful tool for visualizing ASO biodistribution at the subcellular level.
• High-resolution imaging techniques can guide the optimization of ASO delivery strategies to enhance efficacy and minimize toxicity.