Circular RNA PUM1 (CircPUM1) attenuates trophoblast cell dysfunction and inflammation in recurrent spontaneous abortion via the MicroRNA-30a-5p (miR-30a-5p)/JUNB axis

Abstract

Recurrent spontaneous abortion (RSA) is a threat to human reproductive health worldwide. CircPUM1 has been reported to participate in the pathogenesis of various diseases. However, there has been no report on its association with RSA yet. In this study, gene expressions were examined by RT-qPCR. Protein levels of JUNB and cleaved caspases-3 were detected by Western blotting. ELISA was used to detect TNF-α, IL-6, and IL-8 levels. Cell viability, migration, invasion, and apoapsis were analyzed using CCK-8, transwell, and flow cytometry assays. The association between miR-30a-5p and circPUM1 or JUNB was identified by bioinformatics analysis, dualluciferase reporter assay, and RIP assay. Herein, we found circPUM1 was significantly downregulated in RSA placental samples. CircPUM1 knockdown induced decreased proliferation, migration, and invasion, but increased apoptosis, pro-apoptotic protein (cleaved caspases-3) level, and proinflammatory factor (TNF-α, IL-6, and IL-8) secretion in trophoblast cells. Furthermore, we confirmed that circPUM1 was a sponge for miR-30a-5p, and JUNB was directly targeted by miR-30a-5p. It was demonstrated that miR-30a-5p inhibition could reverse trophoblast cell dysfunction and inflammation induced by circPUM1 knockdown. In addition, we found that JUNB expression was negatively modulated by miR-30a-5p and positively regulated by circPUM1. Moreover, circPUM1 inhibition exacerbated dysfunction and inflammation in trophoblast cells via targeting JUNB. To sum up, our study indicated that circPUM1 could impair RSA occurrence and development by facilitating trophoblast cellular processes and protecting against inflammation via the miR-30a-5p/JUNB axis, providing a new target for the improvement of RSA diagnosis and treatment.

Non-coding RNA regulates the immune microenvironment in recurrent spontaneous abortion (RSA): new insights into immune mechanisms

“…CircRNA, as a ceRNA molecule, can stimulate miRNA-induced target gene expression and interact with disease-related miRNAs, reducing miRNA-induced target gene inhibition ( Table 2 ). For example, Circ PUM1 promotes the function of trophoblast cells and fights inflammation by targeting the expression of microRNA-30a-5p/JUNB [ 67 ], thereby reducing the occurrence of RSA. Circ PUM1 and JUNB can simultaneously bind to miR-30a-5p, influencing the expression of regulatory molecules.…”

JunB: a paradigm for Jun family in immune response and cancer

“…It seems that different m6A readers define the distinct fate of JunB transcripts and further studies should compare the binding efficacy of m6A readers to JunB transcripts. Non-coding RNAs, such as miR-939 ( Garbin et al., 2021 ), lincRNA-p21 ( Yoon et al., 2012 ) and circPUM1 ( Zhu et al., 2021 ), have also been identified as upstream regulators of JunB in biological processes. Therefore, post-transcriptional and -translational modification may cooperatively regulate the expression level of JunB at homeostasis ( Figure 2 ).…”

Identification of circRNA Expression Profile and Potential Systemic Immune Imbalance Modulation in Premature Rupture of Membranes

“…Although circRNA has not been adequately studied in the perinatal field, its extraordinary biological activities and clinical significance in gestational diseases have already been shown [ 27 – 29 ]. For instance, circPUM1 could impair recurrent spontaneous abortion occurrence and protect against inflammation via the miR-30a-5p/JUNB axis [ 30 ]. The circ_0001861/miR-296-5p/FOXP1 axis plays a regulating role in trophoblast cell proliferation, migration, invasion, and EMT in pre-eclampsia [ 31 ].…”