Figure 1.

The main process of exosomal long non-coding RNAs (lncRNAs) formation and release. The formation of exosomes stems from the endocytosis of some membrane proteins at the plasma membrane, forming early and late-sorting endosomes. Then intraluminal vesicles (ILVs) are formed through the inward budding of the late-sorting endosomal membrane with encapsulating the substances like proteins, DNAs and RNAs. Finally, late-sorting endosomes mature to multivesicular bodies (MVBs), which release ILVs as exosomes. Otherwise, they fuse with lysosomes to be degraded. Exosomes can directly recognize and transmit signal to recipient cells, as well as fuse with plasma membrane to release cargos. In the other hand, exosomes can be internalized to form endosomes mainly through clathrin-dependent endocytosis, clathrin-independent macropinocytosis, or phagocytosis. Deeping on the needs of cells, the endosomes release exosomal cargos, fuse with lysosomes for degradation, or even fuse with plasma membrane again to recycle exosomes. The exosomal lncRNAs are subsequently released to regulate cell function in various ways. In the cytoplasm, lncRNAs can affect post-transcriptional levels by binding miRNAs, mRNAs, and proteins. Besides, some lncRNAs can even encode short peptides. In the nucleus, lncRNAs can also interact with transcription factors and chromatins, as well as act as enhancer-like RNAs.