Lipid nanoparticles for bone marrow-targeted RNA therapeutics.

Lipid nanoparticle (LNP)-mediated delivery of therapeutic RNA molecules to the bone marrow (BM) holds transformative potential to treat hematological malignancies such as leukemia and for advancing immune and regenerative therapies. Despite this promise, LNPs exhibit poor BM accumulation following systemic administration. Formidable physiological barriers including rapid clearance by the mononuclear phagocyte system, predominant off-target sequestration in the liver, complement activation and inefficient endosomal escape currently limit their efficacy for extrahepatic applications. This review characterizes the complex BM physiology and the multifaceted challenges hindering LNP delivery to this organ. We discuss successful in vivo passive and active targeting strategies, evaluate emerging preclinical in vitro models and highlight innovative LNP design strategies aimed at enhancing particle stability and circulation time. Together, these advances establish a framework for the next-generation of RNA-therapeutics dedicated to treating BM-associated diseases.