Epithelial stem cells are formed by small-particles released from particle-producing cells.

Recent spatiotemporal report demonstrated that epidermal stem cells have equal potential to divide or differentiate, with no asymmetric cell division observed. Therefore, how epithelial stem cells maintain lifelong stem-cell support still needs to be elucidated. In mouse blood and bone marrow, we found a group of large cells stained strongly for eosin and containing coiled-tubing-like structures.

Kidney regeneration by non-platelet RNA-containing particle-derived cells.

We found a group of non-platelet RNA-containing particles (NPRCPs) in human umbilical cord blood. These particles can aggregate, fuse and become non-nucleated cells when cocultured with nucleated cells in vitro. The non-nucleated cells further differentiate into nucleated cells expressing octamer binding transcription factor 4 (OCT4).

Pre-stem cell formation by non-platelet RNA-containing particle fusion.

We found a group of non-platelet RNA-containing particles (NPRCP) in human umbilical cord blood. To understand the origin, characterization and differentiation of NPRCP, we examined cord blood-isolated NPRCP in vitro. The NPRCP range in size from < 1 to 5 μm, have a thin bilayer membrane and various morphological features, contain short RNA and microRNA and express octamer-binding transcription factor 4 (OCT4), sex-determining region Y 2 (SOX2) and DEAD box polypeptide 4 (DDX4).