Ledevin, M. | Search bioRxiv

bioRxiv2024

Conserved RNA-binding protein interactions mediate syntologous lncRNA functions

Syntologous long noncoding RNAs (lncRNAs) are loci with conserved genomic positions that often show little or no sequence similarity. Despite diverging primary sequences, lncRNA syntologs from distant species can carry out similar functions. However, determinants underlying conserved functions of syntologous lncRNA transcripts with no sequence similarity remain unknown. Using CASC15 and melanoma formation as a paradigm for fast evolving lncRNAs and their functions, we found that human and zebrafish CASC15 syntologs with no detectable sequence similarity retained their function across 450 million years of evolution. Similar to the casc15-deficient zebrafish, CASC15-mutant human melanoma cells show increased cell migration. Expression of human CASC15 in zebrafish rescues loss of casc15 function by attenuating melanoma formation. This conserved function is supported by a set of RNA-binding proteins, interacting with both zebrafish and human CASC15 transcripts. Together, our findings demonstrate that conserved RNA-protein interactions can define functions of rapidly evolving lncRNA transcripts.

molecular biology↗

bioRxiv2024

Advancing Liver Gene Therapy: Enhanced Transduction with GalNAc-Bioconjugated rAAV Capsids

This study investigates novel approaches to improve targeted gene delivery to the liver, a crucial organ for metabolic processes that faces vulnerabilities from various pathologies. Adeno-associated virus (AAV)-based gene therapy has emerged as a promising approach for liver targeting, with numerous investigational avenues. However, administration of high doses of AAV vectors present safety concerns, often requiring the use of corticosteroids and immunosuppression to mitigate immune adverse events. To address this, substantial efforts are underway to engineer optimized capsids to enhance the efficiency and specificity of recombinant AAV (rAAV) targeting hepatocytes, aiming to reduce required dosages. In this study, we employed bioconjugation chemistry to target the Asialoglycoprotein receptor (ASGPR), a C-type lectin abundantly expressed at the surface of hepatocyte membranes. We demonstrated that covalently attaching carbohydrates derived from GalNAc (a known ASGPR ligand) to lysine amino-acids on the rAAV2 capsid significantly enhanced in vivo liver transduction efficiency in mice. These optimized vectors present a promising avenue for the treatment of a spectrum of liver diseases, providing an alternative solution within the framework of liver gene therapy.

bioengineering↗