Table 1.

Summary of relevant miRNAs in periodontal disease.

miRNAs	miRNA in Diseased Tissues	Functions	Reference
miRNA-548	Upregulation	Upregulation of IL-8 within the periodontal pocket	[26,27]
miRNA-31	Upregulation	Regulates the expression of ICAM-1, which controls the migration of leukocytes from the bloodstream to the tissues	[29]
miRNA-17	Upregulation	Regulates the expression of E- Selectin, which controls the migration of leukocytes from the bloodstream to the tissues	[15]
miRNA146	Upregulation	Negatively regulates the TLR signalling pathway	[30,31]
miRNA-146a	Upregulation	Negatively regulates TLR signalling; reduced expression of NF-κb, TNFα, IL-1β and IL-6, which induce osteoclastogenesis	[54]
miRNA-146b	Upregulation	Negatively regulates TLR signalling	[54]
miRNA-155	Downregulation	Regulates TLR release in inflamed tissues	[54]
miRNA-200	Upregulation	Reduces the release of IL-6, IL-8, IFRD1 and NF-κb	[38]
miRNA-200c	Upregulation	Regulatory effect on TLR4-mediated signalling in macrophages	[39]
miRNA-21	Upregulation	Decreases NF-κb activation	[41]
miRNA-let-7	Upregulation	Inhibits TLR4	[42]
miRNA-203	Downregulation	Promotes neo-angiogenesis and regulates innate immunity	[10,28]
miRNA-223	Upregulation	Plays a role in alveolar bone loss	[48,50]