The field of oligonucleotide therapeutics, encompassing siRNA and antisense oligonucleotides (ASOs), is transforming medicine, but its success hinges critically on efficient and specific delivery to the target tissue. CD BioGlyco, an expert biology specialist at the forefront of nucleic acid chemistry, has engineered a powerful solution: the monoantennary GalNAc-RNA delivery service. This specialized ligand-targeted drug delivery (LTDD) approach uses GalNAc to selectively ferry therapeutic RNA payloads to liver parenchymal cells, or hepatocytes. The liver-specific asialoglycoprotein receptor (ASGPR) serves as the high-capacity gateway for this process, making GalNAc conjugation the gold standard for hepatic targeting. Our monoantennary GalNac-RNA delivery service provides a synthetically streamlined and highly versatile platform for researchers and pharmaceutical partners seeking to accelerate their drug development timelines with proven delivery efficacy.
The foundation of our service lies in exploiting the biology of the ASGPR, a C-type lectin that is abundantly and almost exclusively expressed on the surface of hepatocytes in the liver. The monovalent GalNAc ligand binds to the ASGPR, triggering a process of rapid, clathrin-mediated endocytosis, effectively internalizing the entire conjugate into the hepatocyte. While trivalent GalNAc clusters are known for the highest affinity, our monoantennary strategy focuses on maximizing synthetic accessibility and versatility.
The core technology relies on a non-nucleosidic monovalent GalNAc phosphoramidite building block. This reagent is designed for facile, site-specific incorporation into any oligonucleotide sequence using standard solid-phase DNA synthesis methods. The monovalent GalNAc unit itself is typically comprised of three essential structural components: the GalNAc sugar moiety, a specialized linker moiety, and a branch point (such as trans-4-hydroxyprolinol) to optimize the structure for conjugation. This modular design enables superior quality control and flexibility, paving the way for advanced modifications.
Our monoantennary GalNAc-RNA delivery provides a flexible range of options to tailor the conjugate precisely to your therapeutic needs:
Full support for various oligonucleotide modalities, including ASOs, small interfering RNA (siRNA), microRNA inhibitors, and aptamers.
Seamless conjugation with all major backbone chemistries, including phosphorothioate (PS), phosphodiester (PO), and various combinations, ensuring optimal in vivo stability.
Flexibility to incorporate the monovalent GalNAc ligand at multiple locations, including the 5'-end, 3'-end, or internally, allowing for design optimization based on in vitro and in vivo data.
While focused on the highly efficient monoantennary unit, we also offer the option to serially incorporate multiple monovalent units (di-antennary, tri-antennary, or higher) to finely tune the ASGPR binding affinity and increase potency for challenging targets.
Selection of various linker compositions and lengths to optimize the spatial orientation and stability of the GalNAc moiety, ensuring optimal interaction with the ASGPR trimer.
This initial step involves consultation on the optimal sequence (ASO, siRNA, etc.) and the selection of necessary stabilizing chemical modifications, such as the phosphorothioate backbone and 2'-modifications (e.g., 2',4'-BNA/LNA), to maximize stability and target affinity.
The selected oligonucleotide sequence is synthesized on a solid support. The chemically protected monovalent GalNAc phosphoramidite unit is then coupled to the desired site (e.g., 5'- or 3'-terminus) using automated solid-phase synthesis.
Following successful coupling, the protecting groups on the oligonucleotide and the GalNAc ligand are chemically removed, and the full-length, crude GalNAc-RNA conjugate is cleaved from the solid support.
The crude conjugate is subjected to rigorous multi-step high-performance liquid chromatography (HPLC) purification to isolate the target molecule with exceptional purity, which is critical for successful in vivo delivery studies.
The final purified product is confirmed using advanced analytical techniques, including high-resolution mass spectrometry (MS) to verify molecular weight and concentration, and analytical HPLC/capillary electrophoresis for purity assessment.
The fully characterized GalNAc-RNA conjugate is formulated according to client specifications and delivered with a comprehensive certificate of analysis (CoA), ensuring complete transparency and readiness for subsequent biological studies.
Journal: Nucleic Acids Research
DOI: 10.1093/nar/gkae350
Published: 2024
IF: 13.1
Results: This study systematically evaluates the feasibility of orally administering GalNAc-conjugated siRNAs in rodents and non-human primates (NHPs). The authors investigate whether the high potency and metabolic stability of modern, chemically modified siRNAs can overcome the significant challenges of oral delivery for large macromolecules, primarily poor intestinal permeability and pre-systemic degradation. They co-formulated GalNAc-siRNAs with various permeation enhancers (PEs), with sodium caprate (C10) emerging as the most effective, and administered them via oral gavage. The research demonstrates that robust and durable RNA interference (RNAi) activity can be achieved in both mice and cynomolgus monkeys following oral administration, confirming that the siRNAs are absorbed, reach the liver, and functionally engage the RNAi machinery in hepatocytes via the asialoglycoprotein receptor (ASGPR). However, the oral bioavailability was found to be low (<2%), with intestinal permeability identified as the major limiting factor, influenced more by the large size and rigid double-stranded structure of the siRNA than by degradation in the gastrointestinal tract. The study concludes that while oral delivery of GalNAc-siRNAs is pharmacologically active, significant improvements in the potency of both the siRNA and the permeation enhancer are needed to make it a practical therapeutic modality.
Treating Severe Dyslipidemia and Hypercholesterolemia
This service is ideal for creating ASOs and siRNAs that target genes such as apolipoprotein B (apoB) or apolipoprotein C-III (ApoC-III) in the liver, leading to significant and durable reduction of serum lipids and addressing genetic dysregulation.
Gene Silencing for Chronic Viral Infections
The platform is extensively used to target hepatic viruses like Hepatitis B (HBV) and Hepatitis D (HDV), where highly specific delivery of siRNAs can interrupt viral replication cycles and reduce viral load with high efficiency.
Developing Therapies for Genetic Clotting Disorders
Conjugated oligonucleotides can precisely modulate the expression of liver-synthesized proteins involved in the coagulation cascade, offering therapeutic strategies for conditions like Hemophilia or Thrombotic disorders by targeting factors such as Antithrombin.
Research into Non-Alcoholic Steatohepatitis (NASH)
Our delivery system is a crucial tool for researchers investigating gene targets and pathways implicated in NASH and non-alcoholic fatty liver disease (NAFLD), enabling precise knockdown for functional studies.
Gold-Standard Liver-Specific Targeting
Our service harnesses the ASGPR, which is one of the most abundant, high-capacity receptors on the hepatocyte surface, guaranteeing a successful and highly selective drug internalization route.
Tuned and Scalable Efficacy
The serial incorporation method allows the single monovalent unit to be coupled repeatedly, enabling the creation of di- or tri-valent structures with tunable efficacy, with evidence showing knockdown activity is positively correlated with the number of GalNAc units incorporated.
Validated Platform for siRNA and ASO Drugs
GalNAc-conjugated oligonucleotides have demonstrated great success in both siRNA (RNAi) and antisense (RNase H-mediated) mechanisms of action, establishing our platform as a universally applicable delivery system for nucleic acid therapies.
Fast and Consistent Cellular Uptake Kinetics
The ASGPR undergoes very fast clathrin-mediated endocytosis, with a rapid turnover rate, which ensures quick and highly consistent cellular uptake and predictable pharmacokinetic profiles for your therapeutic agent.
The quality of the monoantennary GalNAc-ASO we received was exceptional, achieving high purity that was critical for our in vivo mouse study. The 5'-conjugation was seamless, and the enhanced liver-specific knockdown allowed us to collect clean, reproducible PK/PD data much faster than anticipated. CD BioGlyco is now our exclusive conjugation partner.
— Dr. Peterson, Senior Scientist, Medicinal Chemistry
We appreciated the CD BioGlyco's guidance on using the monovalent unit serially to fine-tune our efficacy. Their expertise in the ASGPR mechanism saved us months of trial-and-error. The material was delivered ahead of schedule, proving their commitment to speed and scientific rigor. A truly excellent and reliable service.
— Manager Chen, Program Director, Preclinical Development
The switch to CD BioGlyco's monoantennary service immediately streamlined our costs without sacrificing the essential liver-targeting potency. Their ability to deliver high-quality research-grade material in less than a month allowed us to meet a critical internal milestone. I highly recommend their professionalism and scientific depth.
— Lead Researcher, Group Head, Molecular Therapeutics
CD BioGlyco's monoantennary GalNAc-RNA delivery service provides the perfect intersection of cutting-edge scientific delivery technology and streamlined synthetic efficiency. By specifically targeting the ASGPR in the liver, we enable our clients to achieve significant in vivo potency enhancement with a highly reliable therapeutic payload. Our commitment to high purity, flexible design, and expert scientific support ensures your project moves from discovery to clinic with unparalleled speed and confidence. Stop struggling with systemic delivery challenges. Contact us and experience the advantage of precision liver targeting. Our specialist team is standing by to translate your sequence into a successful therapeutic conjugate.
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