Table 3.

In vivo gene therapy CRISPRi studies.

Reference	Treatment Method	Condition	gRNA Target	Experimental Methodology	Results
Moreno et al. 2018 [48]	In vivo knock-down Cellular reprogramming	Autosomal recessive retinitis pigmentosa	Nrl	Dual subretinal injection of AAV.gRNA.dSpCas9-KRAB.N-terminus and AAV.dSpCas9-KRAB C-terminus into Rd10 mouse.	Rods developed a more “cone-like” phenotype. Increased photoreceptor layer thickness. Significantly improved visual function.
Thakore et al. 2018 [54]	In vivo knock-down Treating disease pathways	High LDL cholesterol (familial hypercholesterolemia)	Pcsk9	Dual injection of AAV.dSaCas9-KRAB and AAV.gRNA into mouse tail vein.	80% reduction in target protein. Significant reduction in serum LDL cholesterol.
Chung et al. 2019 [26]	In vivo knock-down Treating disease pathways	Obesity	Fabp4	Intraperitoneal injection of ATS-9R peptide and dSpCas9.gRNA plasmid oligoplex into HFD-induced obesity and diabetes model mice.	Significant reduction in target mRNA. Improved disease symptoms including decrease in body weight, fat mass, and blood glucose.
Yoshida et al. 2018 [57]	In vivo knock-down Treating disease pathways (Experimental methodology required ex vivo knock-down)	Lung squamous cell carcinoma	∆Np63	Lentiviral delivery of dSpCas9-KRAB.gRNA to EBC2 lung SCC cells. Xenograft then injected into adult mice.	Tumour growth significantly repressed
Truong et al. 2019 [58]	Ex vivo knock-down	Calvarial bone healing	PPAR-γ (repression) and Sox9 (activation)	Bacilloviral delivery of all-in-one CRISPRai construct into rat bone marrow-derived mesenchymal stem cells. These were implanted into rat calvarial bone defects.	Significant increase in calvarial bone healing.