RNA interference and antiviral therapy

Table 4 Strategies designed to inhibit SARS-CoV replication via RNA interference

Target gene	RNAi inducer (length)	Promoter	Vector	Model	Delivery methods	Inhib. of virus prod. (fold)	Reference
In vitro studies Viral gene
Leader, TRS, 3’-UTR, S	siRNA (21 bp)	-	-	Vero E6	Transfection	9	[110]
N	shRNA (20 bp)	U6	Plasmid	293	Transfection	NR	[112]
E, M, N	siRNA (21 bp)	-	-	Vero E6	Transfection	> 4	[113]
P	shRNA (19 bp)	H1	Plasmid	Vero	Transfection	> 100	[114]
S	shRNA (22 bp)	U6	Plasmid	Vero E6, 293T	Transfection	-6	[115]
Rep	siRNA (21 bp)	-	-	FRhk-4	Transfection	> 12	[118]
Cellular gene
CHC	siRNA (25 bp)	-	-	HepG2, COS7	Transfection	-1	[116]
In vivo studies
S, NSP12	siRNA (21 bp)	-	-	BALB/C mouse, Rhesus macaque (Macaca mulatta)	i.t.1 and i.n.2 administration	3	[119]

The fold inhibition of virus production refers to the results obtained with the most potent siRNA/shRNA. All siRNAs were prepared by chemical synthesis unless indicated otherwise. TRS: Transcription-regulating sequence; UTR: Untranslated region; S: Spike protein; N: Nucleocapsid protein; NR: Not reported; E: Envelope protein; M: Membrane protein; P: RNA polymerase; Rep: Replicase; FRhk-4: Fatal Rhesus monkey kidney cells; CHC: Clathrin heavy chain; NSP: Non-structural protein; i.t.: Intratracheal; i.n.: Intranasal.

¹siRNA and target-sequence containing reporter plasmid co-administered intratracheally into mouse lungs in D5W or Infasurf solution;

²siRNA instilled intranasally to monkey in D5W solution with different dosing regimens.