Inhibition of Respiratory Syncytial Virus Infections With Morpholino Oligomers in Cell Cultures and in Mice

Abstract

Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infection in infants, young children, and high-risk adults. Currently, there is no vaccine to prevent RSV infection, and the available therapeutic agents are of limited utility. Peptide-conjugated phosphorodiamidate morpholino oligomers (PPMOs) are a class of antisense agents that can enter cells readily and interfere with viral protein expression through steric blocking of complementary RNA. Two antisense PPMOs, designed to target sequence that includes the 5'-terminal region and translation start-site region of RSV L mRNA, were tested for anti-RSV activity in cultures of two human-airway cell lines. Both PPMOs showed minimal cytotoxicity and one of them, (AUG-2), reduced viral titers by >2.0 log(10). Intranasal (i.n.) treatment of BALB/c mice with AUG-2 PPMO before the RSV inoculation produced a reduction in viral titer of 1.2 log(10) in lung tissue at day 5 postinfection (p.i.), and attenuated pulmonary inflammation at day 7 postinfection. These data show that the AUG-2 PPMO possesses potent anti-RSV activity and is worthy of further investigation as a candidate for potential therapeutic application.

Peptides for nucleic acid delivery

“…B-PMO was also successfully used to restore the expression of Bruton´s tyrosine kinase (BTK) by splice switching in a mouse model of X-linked agammaglobulinemia [59]. As antivirals, RXR-based CPP-PMO, targeting the start of the coding region of Human respiratory syncytial virus (RSV) was shown to block viral replication in vivo both in mouse and porcine models of the virus [60,61]. They also displayed activity in reducing murine hepatitis virus (MHV) titers leading to protection from viral associated tissue damage in the liver [62].…”

The Prophylaxis and Treatment with Antiviral Agents of Respiratory Syncytial Virus Infections

“…One such molecule, AUG-2, targeting the L protein has demonstrated anti-RSV activity [65] Host-virus interactions Recent efforts on RSV drug discovery from Bonavia et al [66] have been published. The anti-RSV activity of general, broad-spectrum compounds was extensively assessed.…”

Oxidative Lung Injury in Virus-Induced Wheezing

“…To determine whether antioxidant mimetic treatment of A549 cells affected viral replication, we used two different approaches, the first employing a direct cell-based plaque immunostaining assay (20), while the second used viral antigen detection by Western blot. As shown in Fig.…”

“…A549 cells were treated with different concentrations of EUKs and infected with RSV. At 24 h postinfection, cells extracts were prepared and RSV proteins were detected by Western blot using a polyclonal antibody, as described (20). In RSV-infected cells, viral proteins, including G, N, P, and M, were expressed at comparable levels in untreated and EUKtreated cells using concentrations of 10 and 100 μM, whereas significant lower (EUK-189) or almost no expression (EUK-8) of RSV proteins was detected in infected cells treated with 500 μM of both compounds (Fig.…”

“…3), indicating that antioxidant mimetic treatment can effectively counteract viral-induced cellular oxidative stress. detected by Western blot using a polyclonal antibody, as described (20). In RSV-infected cells, viral proteins, including G, N, P, and M, were expressed at comparable levels in untreated and EUK-treated cells using concentrations of 10 and 100 μM, whereas significant lower (EUK-189)…”