Table 1.

Proposed roles and reported activities for extracellular RNases.

RNases roles	Reported activities	Reference
Cellular immune regulation	–Innate cells’ activation and migration	(46–53)
	–Toll-like receptor pattern recognition and receptor activation	(46, 54, 55)
	–Hematopoiesis	(28)
	–Selective processing of non-coding RNA	(6, 40, 56–59)
	–Release of regulatory tRNA fragments	(6, 41, 58)
Tissue homeostasis, repair and remodeling	–Alarm signalling	(17, 54, 60, 61)
	–Activation and chemotaxis of fibroblasts	(51, 52, 62)
	–Activation of epithelial cells	(51, 52)
	–Cell proliferation activity	(63, 64)
	–Angiogenesis and neo-vascularization	(65, 66)
	–Wound healing activity	(67–70)
	–Autophagy induction	(71, 72)
	–Apoptosis induction	(73–75)
Clearance of extracellular RNA (exRNA)	–Clearance of cellular RNA debris following tissue injury	(29)
	–RNA scavenger activity	(76, 77)
	–Removal of blood exRNA released during hypoxia	(76)
	–Reduction of exRNA pro-inflammatory activity	(29, 78)
Epithelial barrier protection	–Antimicrobial activity at the skin and respiratory, urogenital and intestinal epithelial tracts	(43, 44, 70, 79–85)
Body fluid sterility	–Antibacterial activity	(83, 86–91)
	–Antiparasitic activity	(92–99)
	–Antiviral activity	(100–107)