The role of lncRNA Meg3 in the proliferation of all-trans retinoic acid-treated mouse embryonic palate mesenchymal cells involves the Smad pathway

• DOI: 10.1016/j.reprotox.2021.06.011
• Publication Date: 2021-06-21T15:51:28Z
• Authors: Xiaozhuan Liu; Hongyan Liu; Yang Wu; Zhidong He; Lijun Shen; Huanhuan Zhang; Zhongxiao Wan; Yao Chen; Haodi Yue; Tingting Zhang; Suhua Gao; Zengli Yu
• Keywords: MEG3; Tretinoin

Mesenchymal cell proliferation is critical for the growth of the palate shelf. All-trans retinoic acid (atRA), as well as pathways associated with TGF-β/Smad signaling, play crucial roles in the proliferation of mouse embryonic palate mesenchymal (MEPM) cells. We have found that MEPM-cell proliferation was regulated by atRA and exogenous TGF-β3 could significantly antagonize the atRA-mediated suppression of MEPM cell proliferation, which is closely associated with the regulation of TGF-β/Smad signaling pathway. The long non-coding RNA (lncRNA) MEG3 has been reported to activate TGF-β/Smad signaling, thereby regulating cellular proliferation, differentiation, and related processes. Here, we found that Meg3 expression increased significantly in atRA-treated MEPM cells while TGF-β3 treatment markedly inhibited Meg3 expression and antagonized the effect of atRA on Meg3. Moreover, Smad2 was found to interact directly with Meg3, and atRA treatment significantly enriched Meg3 in Smad2-immunoprecipitated samples. After Meg3 deletion, the effects of atRA on the proliferation of MEPM cells and TGF-β3-dependent protein expression were lost. Hence, we speculate that Meg3 has a role in the RA-induced suppression of MEPM cell proliferation by targeting Smad2 and thereby mediating TGF-β/Smad signaling inhibition.