Identification and characterization of microRNAs in Hymenolepis nana and Hymenolepis microstoma

CUCHER M; MACCHIAROLI N; YONES C; MATÍAS G. PÉREZ

Congreso; medtrop-parasito2019; 2019

The dwarf tapeworm Hymenolepis nana is the most prevalent human tapeworm worldwide, especially affecting children. The mouse bile duct tapeworm Hymenolepis microstoma is a laboratory model for the human parasite H. nana and for other tapeworms causing neglected tropical diseases such as Echinococcus and Taenia. MicroRNAs (miRNAs), a class of small non-coding RNAs, are principle regulators of gene expression at the post transcriptional level and are involved in many different biological processes. In this work we described for the first known time the expression profile of the miRNA complement in Hymenolepis microstoma, and discovered miRNA genes at the genome-wide level in Hymenolepis nana using two different approaches. The high expression of a few miRNAs in the larval stage of H. microstoma is conserved in other cestodes, suggesting that these miRNAs may have important roles in development, survival and host-parasite interplay. We found a reduced complement of evolutionarily conserved miRNAs in both Hymenolepis spp., putatively reflecting their low morphological complexity and parasitic lifestyle. We performed a comparative analysis of the identified miRNAs and examined their genomic arrangement across the Cestoda, providing new insights about their posttranscriptional mechanisms. Our results showed that most miRNAs in Hymenolepis are located in intergenic regions, implying that they are independently transcribed. Interestingly, we found a Hymenolepis-specific cluster composed of three members of the mir-36 family. Also, we found that one of the neighboring genes of mir-10 in H. microstoma is a Hox gene as in most bilaterial species. In addition, some Hymenolepis miRNAs are protostome-specific or bilaterian-specific but divergent from host orthologs, and therefore could represent novel biomarkers for Hymenolepis infection. The comprehensive identification and expression analysis of Hymenolepis miRNAs can help to identify novel biomarkers for diagnosis and/or novel therapeutic targets for the control of hymenolepiasis.