EDNRB Reverses Methylprednisolone-Mediated Decrease in Neural Progenitor Cell Viability via Regulating PI3K/Akt Pathway and lncRNA Expression

To investigate the functions and mechanisms of methylprednisolone (MP) through endothelin receptor B (EDNRB) on the cell proliferation of neural progenitor cells (NPCs) to regulate spinal cord injury.

Primary NPCs were isolated from fetal mice and subjected to treatments with MP and IRL-1620 (EDNRB agonist). The cell viability was determined using the MTS assay. Total RNA was extracted from the cells, and RNA-seq was performed to screen for lncRNAs. The targets of the candidate lncRNAs were predicted by GO and KEGG analyses, and the expressions of lncRNAs were validated via qPCR. Furthermore, protein levels of the PI3K-AKT pathway were determined via Western blotting, and the expression of lncRNAs was detected after inhibiting the pathway with AKT inhibitor.

MTS assays revealed that MP decreased the cell viability of NPCs, whereas the EDNRB agonist reversed this effect of MP. NPCs were used for RNA-seq in the following three groups: normal control (NC), MP, and MP combined with EDNRB agonist (MP + EDNRB). Our results suggested that the NONRATT030699.2, NONRATT004088.2, and NONRATT005601.2 lncRNAs might be involved in the signaling pathway that is correlated to MP and the EDNRB agonist. GO and KEGG pathway analyses revealed that this was the PI3K/AKT pathway. The relevant genes involved in the pathway were validated by Western blotting. The EDNRB agonist promoted cell proliferation mainly via the activation of the PI3K/AKT pathway; however, it suppressed the expression of p-ERK, thereby increasing the expression of cyclin D1 and attenuating the effect of MP in suppressing cell proliferation. Meanwhile, after the AKT signal pathway was inhibited, these lncRNA expressions were consistent with those in the MP + EDNRB group.

MP inhibits NPC proliferation, whereas EDNRB activation reverses the effect of MP via lncRNA.