Reacción a "The ‘dark transcriptome’ has been used to reduce inflammation in mice and human cells"

Traditionally, the human genome has been considered a large instruction book for producing proteins. However, only a small portion of that “text” actually corresponds to coding instructions. Much of the rest is also transcribed into RNA, but without being translated into proteins. Among these molecules are the so-called long noncoding RNAs (lncRNAs): long RNA chains that, far from being genomic “noise,” perform essential regulatory functions, either by directly modulating gene expression or by acting indirectly on various cellular processes.

The article Human and mouse long noncoding RNAs reengineered for exogenous delivery reduce LPS-induced inflammation in human macrophages and mice illustrates well how this knowledge is beginning to have practical applications. The authors “copy” natural lncRNAs involved in inflammation, modify them to make them more stable and resistant to degradation, and encapsulate them in lipid nanoparticles, similar to those used in RNA vaccines. In doing so, they explore their therapeutic potential both in cellular models (human and murine macrophages treated with LPS) and in an animal model of LPS-induced inflammation. In both cases, administration of the modified lncRNAs reduced inflammatory markers.

This approach has several advantages. On the one hand, it starts from lncRNAs that are already present in the organism and whose physiological function is at least partially characterized, making it possible to rely on molecules “validated by biology” rather than on entirely synthetic designs. On the other hand, the strategy opens the door to a new category of RNA-based therapies that do not aim to replace proteins but rather to intervene directly in gene regulatory networks.

Nevertheless, the greatest challenge remains the effective delivery of nucleic acids. In this study, the choice of an “accessible” target such as the immune system—reachable through systemic administration—allows for a promising proof of principle. Extending this approach to other tissues—especially the central nervous system or skeletal muscle—poses much greater challenges, both because of the size and accessibility of these tissues and because of the need to cross complex biological barriers.

Overall, this is an inspiring piece of work that reflects the growing maturity of the field: we are moving from discovering what lncRNAs do to beginning to harness what they do. Much still needs to be optimized, but this is a clear sign that noncoding RNAs may come to occupy a place of their own within the therapeutic arsenal of the future.