Comprehensive circRNA expression profile and function network in osteoblast-like cells under simulated microgravity

•Osteoblasts show a lower osteogenic potential during exposure to microgravity.•427 circRNAs and 1912 mRNAs are modulated by microgravity in osteoblasts.•The dysregulated mRNAs are enriched in various GO terms and KEGG pathways.•As a gravity-sensitive circRNA, circ_014154 may play a vital role in osteoblasts.•CeRNA network reveals the potential connection of circRNAs, miRNAs and mRNAs. Circular RNAs (circRNAs) are a new class of non-coding RNA with a stable structure formed by special loop splicing. Research increasingly suggests that circRNAs play a vital role in the pathogenesis and progression of various diseases. However, the roles of circRNAs in osteoblast differentiation under microgravity remain largely unknown. Here, we investigated the roles and mechanobiological response of circRNAs in osteoblasts under simulated microgravity. Differential circRNA and mRNA expression profiles of MC3T3-E1 cells during exposure to microgravity were screened by RNA transcriptome sequencing technology (RNA-seq). The selected RNAs were validated using quantitative real-time polymerase chain reaction (qRT-PCR). Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were applied for gene function analyses. A total of 427 circRNAs and 1912 mRNAs were differentially expressed along with osteogenic differentiation in the simulated microgravity group (SMG) compared to the control group (CON). Of these, 232 circRNAs and 991 mRNAs were upregulated, whereas 95 circRNAs and 921 mRNAs were downregulated (fold change ≥ 2, p