Method and reagent for the treatment of asthma and allergic conditions

#The present invention relates to therapeutic compositions and methods for the treatment or diagnosis of diseases or conditions related to allergic response. Specifically, the invention provides compositions and methods for the treatment of diseases or conditions related to levels of factors involved in allergic conditions such as asthma, for example prostaglandin D2 receptor (PTGDR), prostaglandin D2 synthetase (PTGDS) and adenosine A1 receptor (ADORA1). The discussion is provided only for understanding of the invention that follows. This summary is not an admission that any of the work described below is prior art to the claimed invention.

#Asthma is a chronic inflammatory disorder of the lungs characterized by airflow obstruction, bronchial hyper-responsiveness, and airway inflammation. T-lymphocytes that produce TH2 cytokines and cosinophilic leukocytes infiltrate the airways. In the airway and in bronchial alveolar lavage (BAL) fluid of individuals with asthma, high concentrations of TH2 cytokines, interleukin-4 (IL-4), IL-5, and IL-13, are present along with increased levels of adenosine. In contrast to normal individuals, asthmatics respond to adenosine challenge with marked airway obstruction. Upon allergen challenge, mast cells are activated by cross-linked IgE-allergen complexes. Large amounts of prostaglandin D2 (PGD2), the major cyclooxygenase product of arachidonic acid are released. PGD2 is generated from PGH2 via the activity of prostaglandin D2 synthetase (PTGDS). PGD2 receptors and adenosine A1 receptors are present in the lungs and airway along with various other tissues in response to allergic stimuli (Howarth, 1997, Allergy, 52, 12).

#The significance of PGD2 as a mediator of allergic asthma has been established with the development of mice deficient in the PGD2 receptor (DP). DP is a heterotrimeric GTP-binding protein-coupled, rhodopsin-type receptor specific for PGD2 (Hirata et al., 1994, PNAS USA., 91, 11192). These mice fail to develop airway hyperreactivity and have greatly reduced eosinophil infiltration and cytokine accumulation in response to allergens. Upon allergen challenge mice deficient in the prostaglandin D2 (PGD2) receptor (DP) did not develop airway hyperactivity. Cytokine, lymphocyte and eosinophil accumulation in the lungs were greatly reduced (Matsuoka et al., 2000, Science, 287, 2013). The DP −/− mice exhibited no behavioral, anatomic, or histological abnormalities. Primary immune response is not affected by DP disruption.

#FIG. 1 shows examples of chemically stabilized ribozyme motifs. HH Rz, represents hammerhead ribozyme motif (Usman et al., 1996, Curr. Op. Struct. Bio., 1, 527); NCH Rz represents the NCH ribozyme motif (Ludwig & Sproat, International PCT Publication No. WO 98/58058); G-Cleaver, represents G-cleaver ribozyme motif (Kore et al., 1998, Nucleic Acids Research 26, 4116-4120, Eckstein et al., International PCT publication No. WO 99/16871). N or n, represent independently a nucleotide that can be same or different and have complementarity to each other; rI, represents ribo-Inosine nucleotide; arrow indicates the site of cleavage within the target. Position 4 of the HH Rz and the NCH Rz is shown as having 2′-C-allyl modification, but those skilled in the art will recognize that this position can be modified with other modifications well known in the art, so long as such modifications do not significantly inhibit the activity of the ribozyme.

#FIG. 2 shows an example of the Amberzyme ribozyme motif that is chemically stabilized (see for example Beigelman et al., International PCT publication No. WO 99/55857).

#FIG. 3 shows an example of the Zinzyme A ribozyme motif that is chemically stabilized (see for example Beigelman et al., Beigelman et al., International PCT publication No. WO 99/55857).

#Nucleic Acid Molecules and Mechanism of Action

#Antisense: Antisense molecules can be modified or unmodified RNA, DNA, or mixed polymer oligonucleotides and primarily function by specifically binding to matching sequences resulting in inhibition of peptide synthesis (Wu-Pong, Nov 1994, BioPharm, 20-33). The antisense oligonucleotide binds to target RNA by Watson Crick base-pairing and blocks gene expression by preventing ribosomal translation of the bound sequences either by steric blocking or by activating RNase H enzyme. Antisense molecules can also alter protein synthesis by interfering with RNA processing or transport from the nucleus into the cytoplasm (Mukhopadhyay & Roth, 1996, Crit. Rev. in Oncogenesis 7, 151-190).

#In addition, binding of single stranded DNA to RNA can result in nuclease degradation of the heteroduplex (Wu-Pong, supra; Crooke, supra). To date, the only backbone modified DNA chemistry which act as substrates for RNase H are phosphorothioates, phosphorodithioates, and borontrifluoridates. Recently it has been reported that 2′-arabino and 2′-fluoro arabino-containing oligos can also activate RNase H activity.