Expression of microRNAs in African swine fever virus infected pigs.

African swine fever (ASF) is a re-expanding devastating viral disease currently threatening the pig industry worldwide. MicroRNAs are a class of 17- 25 nucleotides non- coding RNAs that have been shown to have critical functions in a wide variety of biological processes, such as cell differentiation, cell cycle regulation, carcinogenesis, apoptosis, regulation of immunity as well as in viral infections by cleavage or translational repression of mRNAs. In this work, we have analyzed miRNAs expressed in spleen and submandibular lymph node of pigs experimentally infected with a virulent (E75) or its derived attenuated (E75CV1) strain. The objective of this work was to analyze differences in miRNA expression between these two viruses and those found at different times post-infection with the virulent strain. Spleen presented a more differential expression pattern than lymph nodes. The differentially expressed miRNAs identified in this work have been associated with cellular genes involved in pathways related to the immune response and virus-host interaction as well as with viral genes . This is, in our knowledge, the first description of miRNA regulation by AFSV in vivo. The study of the miRNAs expression will contribute to better understanding African swine fever virus pathogenesis, essential in the development of any disease control strategy.