Table 2.

Targeting miRNA genes and miRNA transcripts by CRISPR/Cas in vivo and in vitro studies

Type of CRISPR	Purpose of use	miRNA	Target	Type of diseases	Cell line (in vitro)	Animal (in vivo)	Vector	Finding	References
CRISPR/dCas9	Therapy	miR-155	–	Liver cancer	HEK293T, AML12	–	Lentivirus	Exosomes are modified to transport and deliver novel RNA payload to target cells	[84]
CRISPR/Cas9	Therapy	miR-155	S PU.1, AID, SHIP1, SMAD5, and SOCS1	RA	RAW264.7 and HEK293T	–	Lentivirus	Genome editing with miRNA-155 holds promise as a treatment for RA	[82]
CRISPR/Cas9	Function investigation	10 miRNA genes	–	–	–	Zebrafish	–	Cas9 nuclease with 2, 4, 10 or > 24 multiplexed sgRNA can cause mutations in 90% of miRNA genome	[85]
CRISPR/Cas9	Therapy and pathway investigation	miRNA-26a-1 miRNA-26a-2	–	Respiratory distress syndrome	–	Mice (C57BL/6J and FVB)	–	miR-26a has a role in PS synthesis in AECIIs	[86]
CRISPR/Cas9	Function investigation	miR-196a miR-219	–	Neurocristopathies	–	Xenopus	–	miRNA mimics have been applied to recover the knockout phenotype Knocking out miR-219 and miRNA-106a related to loss of NC and hatching gland abnormalities in mice	[87]
CRISPR/Cas9	Therapy	miR122	–	HCV	Huh7	–	Adeno-associated virus	Creating tailored cellular clones that resemble to the parental cells yet are immune to HCV multiplication and infection	[88]
CRISPR/Cas9	Function investigation	miR-4018a	–	–	–	Ciona embryo	Electroporation	MICR-ON is used to observe and analyze miRNA expression and function in a living organism and its biological system	[89]
CRISPR/Cas9	Function investigation	miR17 family	Fog2	–	E14	Mouse	–	Varied members of the miRNA17 family (14 miRNAs) have different functions in embryonic stem cell development	[90]
CRISPR/Cas9	Investigation	–	–	–	HEK293T	–	–	A pool of transiently transfected cells must allow functional examination of a hypothesized miRNA-target combination using clonal cell lines or transgenic animals	[91]
CRISPR/Cas9	Therapy	miR-17 miR-200c miR-141	–	Colorectal cancer	HCT116 and HT-29	–	Lenti-CRISPR	Suppressing miRNAs by up to 96% in robustness by using CRISPR/Cas9 CRISPR/Cas9 regulates off-targeting on miRNAs from the same family or with a similar sequence It has been demonstrated how CRISPR/Cas9 miRNA knockdown is stable over the long term	[77, 92]
CRISPR/Cas9	Testing the methods	miRNA-29b1	–	–	–	Mice (C57BL/6)	–	Knocking out miRNA-29b1 gene in mice A 10 bp deletion, a 23 bp loss, and a 3 bp insertion have been seen in mouse genotypes miRNA-29b1 expression was down-regulated in the kidneys, liver, heart, spleen, and lung	[93]
CRISPR/Cas9	Function investigation	miR-31-5p miR-92b-3p miR-146b-5p miR-151a-3p miR-194-5p miR-95-3p miR-181a-5p miR-188-5p miR-196b-5p miR-584-5p miR-1304-3p miR-100-5p miR-149-5p	–	Cervical and gastric cancer	HeLa or NCI-N87	–	Lentivirus	Five HeLa pro-fitness and cervical cancer up-regulated miRNAs were found There was an up-regulation of six NCI-N87 profit and gastric cancer miRNAs Three down-regulated and anti-fitness miRNAs were found	[94]
CRISPR/Cas9	Function investigation	miR-497 miR-195 miR-143 miR-145	–	Cardiovascular diseases and cancer	VSMCs, HEK293T	–	Lentivirus	Editing miR-195 decreased miR-497a expression in the miR-497195 cluster. Despite the absence of gene editing in the miR-497a genomic region, computational simulation demonstrated a change in the three-dimensional form of the pri-miR-497-195	[95]

RA rheumatoid arthritis, AID acquired immune deficiency, SHIP1 SH2-containing inositol-5ʹ-phosphatase 1, SMAD5 SMAD family member 5, SOCS1 suppressor of cytokine signaling 1, PS pulmonary surfactant, AECIIs alveolar type II epithelial cells, NC neurocristopathies, HCV hepatitis C virus, VSMCs vascular smooth muscle cells, bp base pair, sgRNA single-guide RNA, MICR-ON miRNA-inducible CRISPR-on system