Cells communicate with one another to create microenvironments and share resources. One avenue by which cells communicate is through the action of exosomes. Exosomes are extracellular vesicles that are released by one cell and taken up by neighbouring cells. But how exosomes instigate communication between cells has remained largely unknown. Researchers from the University of New South Wales present evidence here that particular long non-coding RNA molecules are preferentially packaged into exosomes. They also find that a specific class of these exosome associated non-coding RNAs functionally modulate cell viability by direct interactions with L-lactate dehydrogenase B (LDHB), high-mobility group protein 17 (HMG-17), and CSF2RB, proteins involved in metabolism, nucleosomal architecture and cell signalling respectively. Knowledge of this endogenous cell to cell pathway, those proteins interacting with exosome associated non-coding transcripts and their interacting domains, could lead to a better understanding of not only cell to cell interactions but also the development of exosome targeted approaches in patient specific cell-based therapies.
Model for exosomal mediated spread of lncRNAs
(A) RNAs Exo1-4 and RMRP may interact with host proteins or may be free of interactions and be packaged into exosomes by a specific, yet to be determined set of exosomal directed proteins. (B) The lncRNA containing exosomes are blebbed from the cell and can then (C) interact with recipient target cells. Once inside the recipient cells the lncRNAs can (D) bind proteins, such as Exo1, Exo4 and RMRP binding to CSF or Exo2 binding to LDHB or Exo4 binding HGM-17 (HGM) to affect protein function and cellular states. (E) Some yet to be characterized exosomal-associated lncRNAs such as RMRP may interact with epigenetic regulatory mechanisms to control particular gene expression states by (F) targeting stable epigenetic marks that may lead to targeted heterochromatin.