microRNA-422a Inhibits DCC Expression in a Manner Dependent on SNP rs12607853.

DCC netrin 1 receptor (DCC) affects the structure and function of the dopamine circuitry, which in turn affects the susceptibility to developing addiction. In a previous study, we found that single nucleotide polymorphism (SNP) rs12607853 in the 3' untranslated region (3'-UTR) of DCC was significantly associated with heroin addiction. In the current study, we first used bioinformatics prediction to identify the DCC rs12607853 C allele as a potential hsa-miR-422a and hsa-miR-378c target site. We then used vector construction and dual-luciferase reporter assays to investigate the targeting relationship of DCC rs12607853 with hsa-miR-422a and hsa-miR-378c. The dual-luciferase reporter gene assay confirmed that the C allele of rs12607853 in combination with hsa-miR-422a led to repressed dual-luciferase gene expression. Moreover, gene expression assays disclosed that hsa-miR-422a inhibited DCC expression at both the mRNA and protein levels. We also found that morphine inhibited the expression of hsa-miR-422a but increased the expression of DCC mRNA, and this change in the expression of hsa-miR-422a could not be reversed by naloxone, which suggested that the role of DCC in opioid addiction might be regulated by hsa-miR-422a. In summary, this study improves our understanding of the role of hsa-miR-422a and identifies the genetic basis of rs12607853, which might contribute to the discovery of new biomarkers or therapeutic targets for opioid addiction.

Integrative RNA profiling of TBEV-infected neurons and astrocytes reveals potential pathogenic effectors.

Tick-borne encephalitis virus (TBEV), the most medically relevant tick-transmitted flavivirus in Eurasia, targets the host central nervous system and frequently causes severe encephalitis. The severity of TBEV-induced neuropathogenesis is highly cell-type specific and the exact mechanism responsible for such differences has not been fully described yet. Thus, we performed a comprehensive analysis of alterations in host poly-(A)/miRNA/lncRNA expression upon TBEV infection in vitro in human primary neurons (high cytopathic effect) and astrocytes (low cytopathic effect). Infection with severe but not mild TBEV strain resulted in a high neuronal death rate. In comparison, infection with either of TBEV strains in human astrocytes did not. Differential expression and splicing analyses with an in silico prediction of miRNA/mRNA/lncRNA/vd-sRNA networks found significant changes in inflammatory and immune response pathways, nervous system development and regulation of mitosis in TBEV Hypr-infected neurons. Candidate mechanisms responsible for the aforementioned phenomena include specific regulation of host mRNA levels via differentially expressed miRNAs/lncRNAs or vd-sRNAs mimicking endogenous miRNAs and virus-driven modulation of host pre-mRNA splicing. We suggest that these factors are responsible for the observed differences in the virulence manifestation of both TBEV strains in different cell lines. This work brings the first complex overview of alterations in the transcriptome of human astrocytes and neurons during the infection by two TBEV strains of different virulence. The resulting data could serve as a starting point for further studies dealing with the mechanism of TBEV-host interactions and the related processes of TBEV pathogenesis.