Long non-coding RNA MEG3 attends to morphine-mediated autophagy of HT22 cells through modulating ERK pathway

Abstract

Context: Morphine is an alkaloid isolated from the poppy plants. The addiction of morphine is a very serious social issue. Some long non-coding RNAs (lncRNAs) have been proposed to engage in drug addiction.

Objective: Whether lncRNA maternally expressed gene 3 (MEG3) attended to morphine-mediated autophagy of mouse hippocampal neuronal HT22 cells was probed.

Materials and methods: HT22 cells were subjected to 10 µM morphine for 24 h. Cell autophagy was assessed by measuring LC3-II/LC3-I and Beclin-1 expression. qRT-PCR was carried out to measure MEG3 expression. SiRNA oligoribonucleotides targeting MEG3 (si-MEG3) was transfected to silence MEG3. The orexin1 receptor (OX1R), c-fos, p/t-ERK and p/t-PKC expressions were tested by western blotting. SCH772984 was used as an inhibitor of ERK pathway.

Results: Morphine elevated OX1R (2.92 times), c-fos (2.06 times), p/t-ERK (2.04 times) and p/t-PKC (2.4 times), Beclin-1 (3.2 times) and LC3-II/LC3-I (3.96 times) expression in HT22 cells. Moreover, followed by morphine exposure, the MEG3 expression was also elevated in HT22 cells (3.03 times). The silence of MEG3 lowered the Beclin-1 (1.85 times), LC3-II/LC3-I (2.12 times), c-fos (1.39 times) and p/t-ERK (1.44 times) expressions in morphine-treated HT22 cells. Inhibitor of ERK pathway SCH772984 further promoted the influence of MEG3 silence on morphine-caused Beclin-1 (1.97 times) and LC3-II/LC3-I (1.92 times) expressions decreases.

Conclusions: Up-regulation of MEG3 attended to the morphine-caused autophagy of HT22 cells might be through elevating c-fos expression and promoting ERK pathway activation. More experiments are also needed in the future to analyse the influence of other lncRNAs in drug addiction.

Keywords:

• Drug addiction
• morphine
• cell autophagy
• LncRNA maternally expressed gene 3
• orexin1 receptor

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Additional information

Funding

This work was supported by the Science and Technology Innovation Talents in Universities of Henan Province (No. 17HASTIT050) and Science and Technology Research Key Projects of Education Department of Henan Province (No. 14A310008).

This work was supported by the Science and Technology Innovation Talents in Universities of Henan Province (No. 17HASTIT050) and Science and Technology Research Key Projects of Education Department of Henan Province (No. 14A310008).