Chemical modifications of small interfering (si)RNAs are used to enhance their stability and potency, and to reduce possible off-target effects, including immunogenicity. We have earlier introduced highly effective antiviral siRNA swarms against herpes simplex virus (HSV), targeting 653 bp of the essential UL29 viral gene. Here, we report a method for enzymatic production and antiviral use of 2′-fluoro-modified siRNA swarms. Utilizing the RNA-dependent RNA polymerase from bacteriophage phi6, we produced 2′-F-siRNA swarms containing either all or a fraction of modified adenosine, cytidine or uridine residues in the antisense strand of the UL29 target. The siRNA containing modified pyrimidines demonstrated high resistance to RNase A and the antiviral potency of all the UL29-specific 2′-F-siRNA swarms was 100-fold in comparison with the unmodified counterpart, without additional cytotoxicity. Modest stimulation of innate immunity signaling, including induced expression of both type I and type III interferons, as well as interferon-stimulated gene 54, by 2′-F-cytidine and 2′-F-uridine modified siRNA swarms occurred at early time points after transfection while the 2′-F-adenosine-containing siRNA was similar to the unmodified antiviral siRNA swarm in this respect. The antiviral efficacy of the 2′-F-siRNA swarms and the elicited cellular innate responses did not correlate suggesting that innate immunity pathways do not significantly contribute to the observed enhanced antiviral activity of the modified siRNAs. The results support further applications of enzymatically produced siRNA molecules with incorporated adenosine nucleotides, carrying fluoro-modification on ribose C2′ position, for further antiviral studies in vitro and in vivo .
Acyclovir is the drug of choice for the treatment of herpes simplex virus (HSV) infections. Acyclovir-resistant HSV strains may emerge, especially during long-term drug use, and subsequently cause difficult-to-treat exacerbations. Previously, we set up a novel treatment approach, based on enzymatically synthesized pools of siRNAs, or siRNA swarms. These swarms can cover kilobases-long target sequences, reducing the likelihood of resistance to treatment. Swarms targeting the UL29 essential gene of HSV-1 have demonstrated high efficacy against HSV-1 in vitro and in vivo. Here, we assessed the antiviral potential of a UL29 siRNA swarm against circulating strains of HSV-1, in comparison with acyclovir. All circulating strains were sensitive to both antivirals, with the half-maximal inhibitory concentrations (IC50) in the range of 350–1911 nM for acyclovir and 0.5–3 nM for the UL29 siRNA swarm. Additionally, we showed that an acyclovir-resistant HSV-1, devoid of thymidine kinase, is highly sensitive to UL29 siRNA treatment (IC50 1.0 nM; Imax 97%). Moreover, the detected minor variations in the RNAi target of the HSV strains had no effect on the potency or efficacy of UL29 siRNA swarm treatment. Our findings support the development of siRNA swarms for the treatment of HSV-1 infections, in order to circumvent any potential acyclovir resistance.
Novel metal-organic frameworks [Eu2L3(DMSO)2(MeOH)2] x 2 DMSO x 3 H2O, 1, and [Zn2L2(DMSO)2] x 1.6 H2O, 2, (L = 4,4'-ethyne-1,2-diyldibenzoate) have been synthesized and structurally characterized. Compound 1 is a 3D open framework while 2 features interpenetrating 2D sheets in the crystal lattice. Both compounds have been characterized with X-ray crystallography, elemental analysis, and thermogravimetric analysis. Compounds 1 and 2 are red and blue-green luminescent, respectively, in the solid state at ambient temperature. Thermogravimetric analysis implies that the extensive interpenetration stabilizes the lattice of 2, although it diminishes the porosity at the same time. The luminescence of 1 can be reversibly quenched and restored by the addition and removal of iodine.
A variety of experimental data on the pressure dependence of the flow of gases through capillaries are examined using the model presented in Part I. The model is found to provide a good description of flow and self-diffusion in capillaries of arbitrary length-to-radius ratio at pressures ranging from the near free molecule to the continuum regimes. Experimental free-molecule flows are found to differ from those predicted from existing theories based on the diffuse scattering of gas molecules by the capillary wall. The differences, which in general cannot be explained by specular reflection, are found to depend on the geometrical structure of the surface, the length-to-radius ratio of the capillary, and on the gas being transported. For a given gas flowing through a capillary of given length-to-radius ratio, the slip contribution to the transport is found to be a monotonically increasing function of the ratio of observed-to-theoretical free-molecule transports.
A model is presented for describing transport under a partial pressure gradient (self-diffusion) as well as transport under a total pressure gradient in capillaries of arbitrary length-to-radius ratio over a pressure range extending from the free molecule to the continuum regimes. The model provides a unified description of the transport and yields the same results as existing theories in the limited ranges appropriate for their application.
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