Characterization of Enterovirus Associated m6A RNA Methylation in Children With Neurological Symptoms: A Prospective Cohort Study

m6A reader proteins: the executive factors in modulating viral replication and host immune response

N6-Methyladenosine (m6A) modification is the most abundant covalent modification of RNA. It is a reversible and dynamic process induced by various cellular stresses including viral infection. Many m6A methylations have been discovered, including on the genome of RNA viruses and on RNA transcripts of DNA viruses, and these methylations play a positive or negative role on the viral life cycle depending on the viral species. The m6A machinery, including the writer, eraser, and reader proteins, achieves its gene regulatory role by functioning in an orchestrated manner. Notably, data suggest that the biological effects of m6A on target mRNAs predominantly depend on the recognition and binding of different m6A readers. These readers include, but are not limited to, the YT521-B homology (YTH) domain family, heterogeneous nuclear ribonucleoproteins (HNRNPs), insulin-like growth factor 2 mRNA-binding proteins (IGF2BPs), and many others discovered recently. Indeed, m6A readers have been recognized not only as regulators of RNA metabolism but also as participants in a variety of biological processes, although some of these reported roles are still controversial. Here, we will summarize the recent advances in the discovery, classification, and functional characterization of m6A reader proteins, particularly focusing on their roles and mechanisms of action in RNA metabolism, gene expression, and viral replication. In addition, we also briefly discuss the m6A-associated host immune responses in viral infection.

Enterovirus 71 VP1 promotes 5-HT release by upregulating the expression of ERICH3 and methyltransferase ZC3H13: VP1 promotes 5-HT release by ERICH3 and ZC3H13 upregulation

BACKGROUND AND AIM

The effect of structural viral protein 1 (VP1) on neurological damage caused by enterovirus 71 (EV71) infection is unclear. This study aimed to explore the transcriptome changes in EV infected patients and the role of VP1 on the cell secretion pathway of neuron cells.

METHODS

In our cohort, EV infected patients were enrolled, and RNA-seq analysis was used to evaluate the distinct transcript patterns of cerebrospinal fluid (CSF). The EV71 VP1-overexpressing vector (pEGFP-c3-VP1) was generated and transfected into neuron cells. The relationship between Glutamate Rich 3 (ERICH3) and methyltransferase Zinc Finger CCCH-Type Containing 13 (ZC3H13) and their effect on the serotonin (5-HT) release of neuron cells were explored using small interfering RNA. The expression of ERICH3 and ZC3H13 and concentration of 5-HT were determined using real-time PCR, Western blot, and ELISA, respectively.

RESULT

The expression of ERICH3 and ZC3H13 were significantly upregulated in EV infected patients with neurological symptoms compared to those without (P<0.05). The ERICH3 gene had many N6-methyladenosine (m6A) binding sites that can be regulated by m6A modification. Further, the expression of ERICH3 and ZC3H13 were elevated significantly in EV71-VP1 overexpressing neuron cells (P<0.05). Moreover, ERICH3 or ZC3H13 deficiency could significantly downregulate the release of 5-HT in VP1-overexpressing cells (P<0.05). Nonetheless, ERICH3 expression was significantly suppressed when ZC3H13 was silenced in neuron cells and vice versa (P<0.05).

CONCLUSIONS

EV71-VP1 can promote 5-HT release by upregulating the expression of ERICH3 and ZC3H13. 5-HT might be a novel therapeutic target for EV71 infection-induced fatal neuronal damage.