Differential expression of microRNA species in a freeze tolerant insect, Eurosta solidaginis

Expression of miRNAs in response to freezing and anoxia stresses in the freeze tolerant fly Eurosta solidaginis

“…To build upon this family of cold-modulated miRNAs, the present work reports the amplification of four miRNAs with functions linked to key signaling pathways involved in cell growth and metabolism (miR-8, miR-9, miR-92b and miR-277), analyzing the responses of these miRNAs to freezing or anoxia exposures in E. solidaginis. MiR-8 and miR-92b can regulate key targets in the PTEN/PI3K/Akt pathway and influence cell metabolism in fly and mammalian models [19,31], whereas miR-9 and miR-277 have been shown to be differentially expressed in selected hypometabolic models [7,9]. This study reports, in frozen and anoxic E. solidaginis, the differential expression of miR-92b, the latest miRNA to join the growing list of CryomiRs.…”

“…These small RNA molecules are differentially regulated in a host of species that utilize hypometabolism as a stress survival strategy, including the hibernating ground squirrel Ictidomys tridecemlineatus [27], the aestivating sea cucumber Apostichopus japonicus [7], the freeze tolerant wood frog R. sylvatica [3], the intertidal snail Littorina littorea [5], and two cold-hardy gall forming insects including the goldenrod gall fly E. solidaginis [9,32]. Cold acclimation and freeze tolerance is a well-documented event in E. solidaginis [46].…”

“…Differential miRNA expression has been reported in various models of hypometabolism including hibernating mammals [37], freeze tolerant frogs [3], and cold-hardy insects [9,32]. Mir-1, capable of targeting a large number of transcript targets including histone deacetylases (HDACs) and Hsp60, is a hallmark example of an over-expressed miRNA in cold-stressed E. solidaginis larvae [32].…”

Insight into post-transcriptional gene regulation: stress-responsive microRNAs and their role in the environmental stress survival of tolerant animals

“…Highlighting the role of miRNAs in the regulation of the hypometabolic state, studies have documented stress-responsive miRNA expression during mammalian hibernation (Morin et al, 2008;Kornfeld et al, 2012;Maistrovski et al, 2012;Biggar and Storey, 2014a), frog and insect freeze tolerance (Biggar et al, 2009;Courteau et al, 2012) and turtle and marine snail anoxia tolerance (Table 1) . These studies collectively indicate a conserved principle of miRNA stressresponse across phylogeny.…”

“…However, it must be noted that this high degree of mature miRNA conservation is primarily restricted to vertebrate organisms, and invertebrate miRNA studies require further optimization given the limited information and high variability of miRNA sequences . Although the detection and quantification of invertebrate miRNAs is typically more difficult than for vertebrates, it has been carried out in both freeze-tolerant intertidal snails (Littorina littorea) and in cold-hardy insects (Epiblema scudderiana and Eurosta solidaginis) Courteau et al, 2012;Lyons et al, 2013). let-7a, miR-124, miR-1b, miR-2010, miR-2013, miR-252a, miR-716b, miR-71a, miR-73b, miR-79, miR-9, miR-92 Down: miR-100, miR-133a/b/c/d, miR-222, miR-29b, miR-33a Chen and Storey, 2014 MicroRNA regulation during stress adaptation…”