Effects of circPICALM-miR-132-PHKB regulated by METTL3 on proliferation of porcine skeletal muscle satellite cells.

Circular RNA (circRNA) is ubiquitously expressed in highly differentiated eukaryotes, playing an extremely vital regulatory role in muscle growth and development. In this study, we identified circPICALM, a novel circRNA which consists of exons 5 to 9 of the PICALM gene, exhibiting differential expression in the longissimus dorsi muscle (LD) of adult (QA) and newborn (QN) Queshan Black pigs. CircPICALM is resistant to RNase R, mainly located in the cytoplasm with potential coding capacities. When circPICALM was over-expressed in porcine skeletal muscle satellite cells (PSMSCs), there was a significant decrease in the expression levels of PCNA, CDK4, CDK1 and CCND1, which consequently inhibited the proliferation of PSMSCs. Conversely, miR-132, a target molecule of circPICALM, was found to promote the proliferation of PSMSCs. In addition, circPICALM can up-regulate the expression of the target gene PHKB by competitively adsorbing miR-132. The circPICALM-ssc-miR-132-PHKB regulatory axis is regulated by METTL3, which increases the m6A level of both PSMSCs and circPICALM, thereby promoting the proliferation of PSMSCs. Overall, this study furnishes a fundamental reference for further in-depth exploration of the specific molecular mechanisms underlying m6A modification and circPICALM in muscle development and progression.