Inhibition of microRNA function by antimiR oligonucleotides

Silence

Table 1 Strategies to manipulate microRNA activity for gain- and loss-of-function studies

Loss-of-function
Technology	Characteristics	In vitro	In vivo	References
Genetic knockout animals	Constitutive or conditional	Primary cells	Systemic or organ-specific	[43]
miRNA sponges	Transient to long-term inhibition	Transfection or viral delivery	Lentivirus or AAV-mediated delivery	[45–47]
antimiR oligonucleotides	Transient (in vitro) to long-lasting inhibition	Transfection or unassisted uptake	Unconjugated or 3'-cholesterol modified, i.v., s.c. or i.p. delivery	[48–50]
Target protectors	Transient	Transfection	Embryo injection (zebrafish)	[51–54]
Gain-of-function
Technology	Characteristics	*In vitro*	*In vivo*	References
Transgenic animals	Constitutive or conditional	Primary cells	Systemic or organ-specific	[55, 56]
Synthetic miRNA mimics	Transient	Transfection	Intratumoral injection, ex vivo transfection of cells, i.v. delivery	[57–62]
Vector-mediated miRNA over-expression	Transient to long-term over-expression	Transfection or viral delivery	Lentivirus or AAV-mediated delivery, intranasal delivery	[58–60, 63, 64]