Anti-miRNA103/107 encapsulated in transferrin-conjugated lipid nanoparticles crosses blood-brain barrier and reduces brain ischemic damage

Cross-species RNAi therapy via AAV delivery alleviates neuropathic pain by targeting GCH1

Tetrahydrobiopterin (BH4) expression is normally strictly controlled; however, its intracellular levels increase considerably following nerve damage. GTP cyclohydrolase I (GCH1) plays a crucial role in regulating BH4 concentration, with an upregulation observed in the dorsal root ganglion in cases of neuropathic pain. In this study, we aimed to develop and evaluate the clinical potential of an RNA interference-based adeno-associated virus (AAV) targeting GCH1 across various species to decrease BH4 levels and, consequently, alleviate neuropathic pain symptoms. We identified universal small-interfering RNA sequences effective across species and developed an AAV-u-shRNA that successfully suppressed GCH1 expression with minimal off-target effects. Male Sprague Dawley rats were divided into four groups: normal, spared nerve injury, AAV-shCON, and AAV-u-shGCH1. The rats were sacrificed on post-injection day 28 to collect blood for BH4 level assessment. The AAV-u-shGCH1 group demonstrated remarkable improvement in the mechanical withdrawal threshold by PID 28, significantly outperforming the normal, spared nerve injury, and AAV-shCON groups. Plasma BH4 levels confirmed that AAV-u-shGCH1 effectively reduced neuropathic pain by inhibiting BH4 synthesis in vivo, introducing a novel, multispecies-compatible therapeutic strategy. Our results suggest that a single application of AAV-u-shGCH1 could offer a viable solution for neuropathic pain relief.

Navigating the intricate in-vivo journey of lipid nanoparticles tailored for the targeted delivery of RNA therapeutics: a quality-by-design approach

RNA therapeutics, such as mRNA, siRNA, and CRISPR-Cas9, present exciting avenues for treating diverse diseases. However, their potential is commonly hindered by vulnerability to degradation and poor cellular uptake, requiring effective delivery systems. Lipid nanoparticles (LNPs) have emerged as a leading choice for in vivo RNA delivery, offering protection against degradation, enhanced cellular uptake, and facilitation of endosomal escape. However, LNPs encounter numerous challenges for targeted RNA delivery in vivo, demanding advanced particle engineering, surface functionalization with targeting ligands, and a profound comprehension of the biological milieu in which they function. This review explores the structural and physicochemical characteristics of LNPs, in-vivo fate, and customization for RNA therapeutics. We highlight the quality-by-design (QbD) approach for targeted delivery beyond the liver, focusing on biodistribution, immunogenicity, and toxicity. In addition, we explored the current challenges and strategies associated with LNPs for in-vivo RNA delivery, such as ensuring repeated-dose efficacy, safety, and tissue-specific gene delivery. Furthermore, we provide insights into the current clinical applications in various classes of diseases and finally prospects of LNPs in RNA therapeutics.