Morpholino antisense oligo inhibits trans-splicing of pre-inositol 1,4,5-trisphosphate receptor mRNA of Trypanosoma cruzi and suppresses parasite growth and infectivity

Morpholino antisense oligos (MAOs) are used to investigate physiological gene function by inhibiting gene translation or construction of specific alternative splicing variants by blocking cis-splicing. MAOs are attractive drug candidates for viral- and bacterial-infectious disease therapy because of properties such as in vivo stability and specificity to target genes. Recently, we showed that phosphorothioate antisense oligos against Trypanosoma cruzi inositol 1,4,5-trisphosphate receptor (TcIP3R) mRNA inhibit the parasite host cell infection. In the present study, we identified the spliced leader (SL) acceptor of pre-TcIP3R mRNA and synthesized MAO, which inhibited trans-splicing of the transcript (MAO-1). MAO-1 was found to inhibit the addition of SL-RNA to pre-TcIP3R mRNA by real-time RT-PCR analysis. Treatment of the parasites with MAO-1 significantly impaired the growth and infectivity into host cells. These results indicate that MAO-1 is a potential novel drug for Chagas disease and that MAOs inhibiting trans-splicing can be used to investigate the physiology of trypanosomal genes leading to the development of novel drugs.