In VitroAntiviral Activity of Circular Triple Helix Forming Oligonucleotide RNA towards Feline Infectious Peritonitis Virus Replication

Abstract

Feline Infectious Peritonitis (FIP) is a severe fatal immune-augmented disease in cat population. It is caused by FIP virus (FIPV), a virulent mutant strain of Feline Enteric Coronavirus (FECV). Current treatments and prophylactics are not effective. The in vitro antiviral properties of five circular Triple-Helix Forming Oligonucleotide (TFO) RNAs (TFO1 to TFO5), which target the different regions of virulent feline coronavirus (FCoV) strain FIPV WSU 79-1146 genome, were tested in FIPV-infected Crandell-Rees Feline Kidney (CRFK) cells. RT-qPCR results showed that the circular TFO RNAs, except TFO2, inhibit FIPV replication, where the viral genome copy numbers decreased significantly by 5-fold log10 from 1014 in the virus-inoculated cells to 109 in the circular TFO RNAs-transfected cells. Furthermore, the binding of the circular TFO RNA with the targeted viral genome segment was also confirmed using electrophoretic mobility shift assay. The strength of binding kinetics between the TFO RNAs and their target regions was demonstrated by NanoITC assay. In conclusion, the circular TFOs have the potential to be further developed as antiviral agents against FIPV infection.

Current status on treatment options for feline infectious peritonitis and SARS-CoV-2 positive cats

“…However, this cat showed neurological manifestations and was euthanised due to status epilepticus after 38 days of treatment [73]. Moreover, other agents have also been shown to have in vitro antiviral activity against FCoV, including an anti-feline TNF-alpha monoclonal antibody [16]; U18666A (a cholesterol transport inhibitor) [18,74]; diphyllin (a vacuolar ATPase blocker) and its nanoformulation [17] and a circular triple helix forming oligonucleotide RNA [15]. However, no in vivo studies have been reported using these compounds.…”

“…In reviewing treatment options for FIP, numerous older studies describing potential treatments are mostly based on cases without a confirmed diagnosis of FIP and hampered by the lack of well-controlled clinical trials [14]. Likewise, the use of other reported treatment options is currently only supported by in vitro studies rather than through in vivo clinical studies [15,16,17,18]. Despite recent antiviral studies with GC376 and GS-441524 showing great promise against FIPV in naturally and experimentally infected cats [19,20,21], these agents have not yet obtained registration for veterinary use [22,23].…”

“…Likewise, the use of other reported treatment options is currently only supported by in vitro studies rather than through in vivo clinical studies (Choong et al. 2014 ; Doki et al. 2016 ; Hu et al.…”

Enhancing the Therapeutic Delivery of Oligonucleotides by Chemical Modification and Nanoparticle Encapsulation

“…Bai et al used CpG ON as vaccine additive to treat Hepatitis B, due to its ability to promote binding capacity of naïve B cells to the Hepatitis B virus epitopes [ 46 ]; Triple-helix-forming ON is formed by single strand ON inserting into the double stranded DNA. After the insertion, double stranded DNA can’t transcribe mRNA and therefore relevant protein expression is inhibited [ 47 ].…”

Expression profiles of immune mediators in feline Coronavirus-infected cells and clinical samples of feline Coronavirus-positive cats

“…cDNA was synthesized using the SensiFAST™ cDNA Kit (Bioline, UK), as instructed by the manufacturer. Virus quantification was performed using SYBR Green-based real-time PCR as described previously with a slight modification [25]. Briefly, quantitative real-time PCR (qPCR) was performed in a 20 μl reaction consisting of 1 μl cDNA, 1 μl forward primer (1 μmol), 1 μl reverse primer (1 μmol), 7 μl nuclease-free water and 10 μl 2× SensiFAST SYBR® No-ROX mix (Bioline, UK).…”