Discovery and Development of Respirable Antisense Therapeutics for Asthma

Abstract

Respirable antisense oligonucleotides (RASONs) represent a novel class of respiratory therapeutic molecules with the potential to specifically address the challenges posed by the successes of the Human Genome Program, namely, the need to rapidly identify the critical pulmonary disease-relevant drugable targets from the vast pool of 30,000-40,000 human genes and to discover and develop drugs that specifically attack these targets. We have shown that EPI-2010, a RASON targeting the adenosine A1 receptor, a G-protein coupled receptor that has been implicated in the regulation of three major determinants of asthma, can be delivered directly to the target disease tissue as an aerosol formulation. In vivo efficacy, absorption, distribution, metabolism, and excretion (ADME), and safety studies of inhaled EPI-2010 employing animal models of human asthma suggest that the RASON approach enables the specific delivery of efficacious, safe, and long-acting doses of phosphorothioate oligonucleotides to the respiratory tract. Moreover, these data indicate that RASONs truly have the potential to address the respiratory drug discovery bottleneck of the postgenomic era, that is, the ability to rapidly validate disease targets and develop pulmonary disease therapeutics for these validated targets.

Inhibition of no tail (ntl) gene expression in zebrafish by external guide sequence (EGS) technique

“…External guide sequence technique, a novel approach, can specifically cleave target molecular by RNase P. Previous studies have demonstrated that RNA inactivation of targeted mRNA by EGS in vivo can be more effective than gene inactivation by conventional antisense DNA oligonucleotides [13,14], which have a different gene inactivation mechanism by endogenous RNase H [15,16]. Reduced off-site cleavage by EGS is also an advantage of EGS relative to RNAi and antisense technologies [17,18].…”

An RNA external guide sequence ribozyme targeting human interleukin-4 receptor α mRNA

“…Previous studies have demonstrated that EGS-based RNA inactivation of targeted mRNA in vivo can be orders of magnitude more effective than gene inactivation by conventional antisense DNA oligonucleotides [33,34] which have a different mechanism of action either by steric blocking of mRNA translation or by causing DNA/mRNA hybrid degradation by endogenous RNAse H [37,38]. If delivered effectively to pulmonary tissues, inhaled EGS ribozymes could have advantages over conventional antisense DNA oligonucleotides because of their ability to act as a co-catalyst for the ubiquitous RNAse P and the potential for a single EGS to recycle through multiple rounds of mRNA cleavage.…”

Antisense- and RNA interference-based therapeutic strategies in allergy

“…In vivo absorption, tissue distribution, metabolism and excretion, efficacy and safety studies of respirable AS-ONs suggest that these antisense agents can be safely delivered to target respiratory tissues in low, but efficacious doses [17,18].…”