Antiviral and Neuroprotective Role of Octaguanidinium Dendrimer-Conjugated Morpholino Oligomers in Japanese Encephalitis

Japanese encephalitis (JE) is caused by a flavivirus that is transmitted to humans by mosquitoes belonging to the Culex sp. The threat of JE looms over a vast geographical realm, encompassing approximately 10 billion people. The disease is feared because currently there are no specific antiviral drugs available. There have been reports where other investigators have shown that agents that block viral replication can be used as effective therapeutic countermeasures. Vivo-Morpholinos (MOs) are synthetically produced analogs of DNA or RNA that can be modified to bind with specific targeted regions in a genome. In this study the authors propose that in an animal model of JE, MOs specifically designed to bind with specific region of JE virus (JEV) genome, blocks virus production in cells of living organisms. This results in reduced mortality of infected animals. As the major target of JEV is the nerve cells, analysis of brain of experimental animals, post treatment with MOs, showed neuroprotection. Studies in cultured cells were also supportive of the antiviral role of the MOs. The potent anti-sense effect in animals and lack of obvious toxicity at the effective dosage make these MOs good research reagents with future therapeutic applications in JE

Comparison of the Safety and Pharmacokinetics of ST-246® after IV Infusion or Oral Administration in Mice, Rabbits and Monkeys

ST-246® is an antiviral, orally bioavailable small molecule in clinical development for treatment of orthopoxvirus infections. An intravenous (IV) formulation may be required for some hospitalized patients who are unable to take oral medication. An IV formulation has been evaluated in three species previously used in evaluation of both efficacy and toxicology of the oral formulation. plasma concentrations. These effects were eliminated using slower IV infusions. associated toxicity. Shorter infusions at higher doses in NHP resulted in decreased clearance, suggesting saturated distribution or elimination. Elimination half-lives in all species were similar between oral and IV administration. The administration of ST-246 was well tolerated as a slow IV infusion

Pre-mRNA Splicing Modulation by Antisense Oligonucleotides

Pre-mRNA splicing, a dynamic process of intron removal and exon joining, is governed by a combinatorial control exerted by overlapping cis-elements that are unique to each exon and its flanking intronic sequences. Splicing cis-elements are usually 4-to-8-nucleotide-long linear motifs that provide binding sites for specific proteins. Pre-mRNA splicing is also influenced by secondary and higher order RNA structures that affect accessibility of splicing cis-elements. Antisense oligonucleotides (ASOs) that block splicing cis-elements and/or affect RNA structure have been shown to modulate splicing in vivo. Therefore, ASO-based strategies have emerged as a powerful tool for therapeutic manipulation of splicing in pathological conditions. Here we describe an ASO-based approach to increase the production of the full-length SMN2 mRNA in spinal muscular atrophy patient cells

Effect of copper, zinc and cadmium on the promoter of selenoprotein W in glial and myoblast cells

Rat selenoprotein W (SeW) promoter activity was investigated using different concentrations of cadmium, copper, and zinc. Two fragments (404 and 1265 bp) of the SeW promoter, containing a single metal response element (MRE), were ligated into the multiple cloning site of a pGL3-Basic reporter plasmid. The constructs were transfected into cultured C6 (rat glial) and L8 (myoblast) cells and promoter activity measured by means of luciferase reporter gene fused to the SeW promoter fragments in the reporter plasmid. With post-transfection exposure of these cell lines to these metals, copper and zinc, but not cadmium, significantly increased promoter activity of the unmutated 1265 bp (not 404 bp) construct (p<0.05) only in the C6 cells. Mutation of the MRE sequence abolished promoter response to metal exposure but did not eliminate promoter activity. The results suggest that SeW expression in glial cells can be increased on exposure to copper and zinc and that this response is dependent on the MRE sequence present in the SeW promoter

Correction of prototypic ATM splicing mutations and aberrant ATM function with antisense morpholino oligonucleotides

We used antisense morpholino oligonucleotides (AMOs) to redirect and restore normal splicing of three prototypic splicing mutations in the ataxia-telangiectasia mutated (ATM) gene. Two of the mutations activated cryptic 5′ or 3′ splice sites within exonic regions; the third mutation activated a downstream 5′ splice site leading to pseudoexon inclusion of a portion of intron 28. AMOs were targeted to aberrant splice sites created by the mutations; this effectively restored normal ATM splicing at the mRNA level and led to the translation of full-length, functional ATM protein for at least 84 h in the three cell lines examined, as demonstrated by immunoblotting, ionizing irradiation-induced autophosphorylation of ATM, and transactivation of ATM substrates. Ionizing irradiation-induced cytotoxicity was markedly abrogated after AMO exposure. The ex vivo data strongly suggest that the disease-causing molecular pathogenesis of such prototypic mutations is not the amino acid change of the protein but the mutated DNA code itself, which alters splicing. Such prototypic splicing mutations may be correctable in vivo by systemic administration of AMOs and may provide an approach to customized, mutation-based treatment for ataxia-telangiectasia and other genetic disorders