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

Abstract

Living animals are constantly faced with various environmental stresses that challenge normal life, including: oxygen limitation, very low or high temperature, as well as restriction of water and food. It has been well established that in response to these stresses, tolerant organisms regularly respond with a distinct suite of cellular modifications that involve transcriptional, translational and posttranslational modification. In recent years, a new mechanism of rapid and reversible transcriptome regulation, via the action of noncoding RNA molecules, has emerged into post-transcriptional regulation and has since been shown to be part of the survival response. However, these RNA-based mechanisms by which tolerant organisms respond to stressed conditions are not well understood. Recent studies have begun to show that non-coding RNAs control gene expression and translation of mRNA to protein, and can also have regulatory influence over major cellular processes. For example, select microRNAs have been shown to have regulatory influence over the cell cycle, apoptosis, signal transduction, muscle atrophy and fatty acid metabolism during periods of environmental stress. As we are on the verge of dissecting the roles of non-coding RNA in environmental stress adaptation, this Commentary summarizes the hallmark alterations in microRNA expression that facilitate stress survival.

Stress‐responsive microRNAs are involved in re‐programming of metabolic functions in hibernators

“…A number of reviews have reported upregulation of many genes during hibernation process (Andrews, ; Carey, Andrews, & Martin, ; Storey & Storey, ). All the above discussion shows that during hibernation, miRNAs and their target genes could be involved in hypometabolic activities as shown in (Table ) (Biggar & Storey, ). The readers are referred to previously published excellent reviews for detailed discussion of miRNA biogenesis, mechanism of action, and translational repression of miRNAs (Arfat et al, ; Bartel, ; Kim, ; Carrington & Ambros, ; Kim, Han, & Siomi, ; O'Connell, Rao, Chaudhuri, & Baltimore, ; Winter, Jung, Keller, Gregory, & Diederichs, ).…”

Profiling microRNA expression in Atlantic killifish (Fundulus heteroclitus) gill and responses to arsenic and hyperosmotic stress

“…The genetic tools available for gene-environment interaction studies in killifish have recently expanded with the publication of a killifish reference genome (Burnett et al, 2007; Reid et al, 2017). The sequenced genome enables investigation of gene regulatory mechanisms at multiple levels (genetic, epigenetic, transcriptional, post-transcriptional) that facilitate the ability of killifish to acclimate to changes in their environment, and in particular the role of non-coding RNAs, which have been identified as mediators of survival responses in organisms tolerant of environmental stress (Biggar and Storey, 2015). …”

Avoiding apoptosis during mammalian hibernation

“…MicroRNAs bind to complementary mRNA sequences to tag them for degradation or sequestration into subcellular particles for storage. MicroRNA control over specific mRNAs can regulate entire metabolic processes, including apoptosis 4 . For instance, miR-21 binds to mRNA transcripts of pro-apoptotic proteins APAF-1, caspase-3 and PCNA4, leading to their degradation/sequestration to prevent cell death.…”

“…For instance, miR-21 binds to mRNA transcripts of pro-apoptotic proteins APAF-1, caspase-3 and PCNA4, leading to their degradation/sequestration to prevent cell death. MiR-21 levels rose in squirrel muscle during hibernation but decreased in brown fat and also in muscle of little brown bats, suggesting that they regulate apoptosis in a tissue- and species-specific manner 4 . New research also shows that low temperature strengthens binding interactions of microRNAs and target mRNAs 4 .…”

“…MiR-21 levels rose in squirrel muscle during hibernation but decreased in brown fat and also in muscle of little brown bats, suggesting that they regulate apoptosis in a tissue- and species-specific manner 4 . New research also shows that low temperature strengthens binding interactions of microRNAs and target mRNAs 4 . Hence, temperature-sensitive microRNA target recognition could be an unrecognized but crucial mechanism that facilitates torpor by suppressing the translation of pro-apoptotic mRNA at low T b .…”