Gene Editing in Pluripotent Stem Cells and Their Derived Organoids

Table 3

Current challenges of gene editing in different diseases.

	Disease names	Related genes	Editing technologies	Model types	Clinical trials	Challenge points and limitation	Years
Respiratory disorders	CF	CFTR	CRISPR	Organoids	\	Proof of concept only, gene editing off-target effects; needs further evaluation for safety	2013 [57]
			TALEN	Cells	\	Delivery efficiency needs to be improved; targeting accuracy needs to be improved	2019 [58]
			CRISPR	Patient-derived cells	\	Difficulty of in vivo delivery, genetically corrected airway stem cell transplantation and recovery of in vivo mucus cilia transport	2021 [59]
	NSCLC	PD-1	CRISPR	\	Phase I (first)	Underexpansion and low response rate of T cells after gene editing; small study sample	2020 [60]
Circulatory disorders	HC	Protein PCSK9	MegNs	Macaques	\	Off-target effects, with cytotoxicity, immunogenicity to be overcome	2018 [61]
	NS-associated HCM	RAF1	CRISPR	Patient-derived cells	\	RAF1 lacks a nuclear localization sequence (NLS), its translocation mechanism is unknown, and the molecular mechanism of the disease needs to be further explored	2019 [62]
	HC	Ldlr	CRISPR	Mouse	\	Genome editing efficiency to be improved and off-target effects to be overcome	2020 [63]
	NS-associated HCM	LZTR1	CRISPR	Patient-derived cells	\	Proof of concept only, needs in vivo evaluation, patient-specific iPSC-CM model is still immature and needs to be improved	2020 [64]
	LDS	TGFBR1	CRISPR	Patient-derived cells	\	Needs further proof from in vivo experiments, off-target effects	2021 [65]
Infectious diseases	HIV	CCR5	ZFN	\	Yes	A serious adverse event was associated with the infusion of ZFN-modified autologous CD4 T cells, with off-target safety issues to be overcome	2014 [66]
			ZFN	Mouse	\	Reduced proliferation of editorial cells transplanted in vivo, delivery efficiency and targeting accuracy need to be improved	2013 [67]
			TALEN	Cells	\	Delivery efficiency and targeting accuracy need to be improved	2015 [68]
			CRISPR	Mouse	\	Safety issues to be further assessed	2017 [69]
			CRISPR	\	Yes	Off-target efficiency needs to be improved, targeting accuracy needs to be improved, and generalizability needs to be further assessed	2019 [5]
			CRISPR	Patient-derived cells	\	Off-target efficiency needs to be improved, and targeting accuracy needs to be improved	2020 [70]
Hematologic disorders	TDT & SCD	BCL11A	CRISPR	\	Yes	No comprehensive genomic analysis of clinical samples and the generalizability of the results needs to be further determined	2021 [71]
	TDT & SCD	HPFH5	CRISPR	Cells	\	Off-target effects to be overcome and safety to be improved	2016 [72]
	SCD	HBB	CRISPR	Mouse	\	The off-target efficiency needs to be reduced, and more sensitive off-target analysis methods are needed	2019 [73]
	SCD	HBB	CRISPR	Humanized mouse	\	Delivery methods to be optimized and delivery efficiency to be improved	2021 [74]
	ALL	CD52	TALEN	\	Yes	Immunogenicity needs to be further reduced; safety needs to be further tested; small sample size	2017 [75]
	MM	TRAC、CD52	TALEN	Mouse	\	Delivery efficiency needs to be improved, and long-term safety issues need to be further studied	2019 [76]
Neurological disorders	FXS	FMR1	CRISPR	Mouse	\	The off-target efficiency needs to be reduced, more sensitive off-target analysis methods are needed, and safety issues need to be further tested	2018 [77]
	AD	TREM2	CRISPR	Humanized SCD mouse	\	Further analysis of the mechanism of action is needed to find effective therapeutic targets for disease treatment	2020 [78]
	CD	ASPA	TALEN	Mouse	\	Proof of concept only, how to achieve sustained efficacy remains to be addressed, and the issue of safety still needs to be improved	2020 [79]
Ophthalmology	XLRP	RP2	CRISPR	Organoids	\	Retinal-like organs are still immature and need further improvement	2020 [80]
	LCA10	CEP290	CRISPR	Mouse	Yes	Impact of individual differences on safety of off-target effect delivery, durability of efficacy to be further assessed	2019 [81]

AD: Alzheimer’s disease; ALL: acute lymphocytic leukemia; CD: Canavan disease; CF: cystic fibrosis; FXS: fragile X syndrome; HC: hypercholesterolemia; HCM: hypertrophic cardiomyopathy; iPSC-CMs: iPSC-derived cardiomyocytes; LDS: Loeys-Dietz syndrome; LCA10: Leber congenital amaurosis type 10; MM: multiple myeloma; NS: Noonan syndrome; NSCLC: non-small-cell lung cancer; SCD: sickle cell disease; TDT: transfusion-dependent β-thalassemia; XLRP: X-linked retinitis pigmentosa.