Comprehensive Analysis of Differentially Expressed Circular RNAs in Patients with Senile Osteoporotic Vertebral Compression Fracture

A Novel Molecular Regulatory Network in Bone Marrow Mesenchymal Stem Cells for Age-Related Osteoporosis

BACKGROUND

This study evaluates the miRNA-mRNA regulatory networks that potentially influence the senescence mechanisms of bone marrow mesenchymal stem cells (BMSCs) in age-related osteoporosis (ARO). By identifying these networks, the study aims to offer new molecular markers and therapeutic targets for ARO.

METHODS

Five mRNA datasets were analyzed to identify common differentially expressed genes associated with senescence and osteoporosis. Seven hub genes were found to be enriched in the PI3K-Akt signaling pathway, and 22 hub miRNAs potentially regulating these genes. Primary BMSCs were harvested and cultured from seven younger, non-osteoporotic individuals and six older adults with osteoporosis. Expression levels of the hub genes and miRNAs were validated using quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

Expression analysis showed that integrin subunit beta 3 (ITGB3), receptor tyrosine kinase ligand (KITLG), platelet-derived growth factor (PDGFB), and their associated regulatory miRNAs, exhibited significant differences between the two BMSC groups.

CONCLUSION

A newly identified miRNA-mRNA regulatory network may mediate ARO via the PI3K-Akt signaling pathway in BMSCs. These molecular insights provide a foundation for potential therapeutic interventions targeting age-related osteoporosis.

Research progress of circRNA as a biomarker of osteoporosis

Osteoporosis, as a chronic metabolic bone disease, has the characteristic of insidious disease progression, which often leads to relatively delayed disease diagnosis. Therefore, early screening for osteoporosis has become a major public health challenge. The latest research indicates that circRNA is widely involved in the regulation of bone metabolism and is closely related to the occurrence and development of osteoporosis. Based on its high degree of sequence conservation and stability, circRNA has the potential to become a new clinical biomarker. The study of biomarkers is generally based on body fluid samples or adjacent tissue samples, with blood being the most commonly used, which can be divided into sources such as serum, plasma, peripheral blood monocytes, and plasma exosomes. Therefore, this article aims to review the research status of circRNA as a biomarker of osteoporosis.

Circ_KIAA0922 regulates Saos-2 cell proliferation and osteogenic differentiation by regulating the miR-148a-3p/SMAD5 axis and activating the TGF-β signaling pathway

Circular RNAs (circRNAs) are emerging as important regulators in human disease, but their function in osteoporosis (OP) is not sufficiently known. The aim of this study was to identify the possible molecular mechanism of circ_KIAA0922 in osteogenic differentiation of Saos-2 cells in vitro and the interactions among circ_KIAA0922, miR-148a-3p, and SMAD family member 5 (SMAD5). Circ_ KIAA0922, miR-148a-3p, and SMAD5 were overexpressed by transient transfection. Dual-luciferase reporter assay system was used to analyze the combination among circ_KIAA0922, miR-148a-3p, and SMAD5. In addition, the levels of circ_KIAA0922, miR-148a-3p, SMAD5, osteocalcin (OCN), and runt-related transcription factor 2 (RUNX2) were detected using RT-qPCR or western blot analysis. Alizarin red staining was performed to analyze the degree of osteogenic differentiation under the control of circ_KIAA0922, miR-148a-3p, and SMAD5. We found that circ_KIAA0922 knockdown inhibited the proliferation and osteogenic differentiation of Saos-2 cells. Circ_KIAA0922 directly targeted miR-148a-3p, and miR-148a-3p inhibition reversed the effects of circ_KIAA0922 knockdown on the proliferation and osteogenic differentiation of Saos-2 cells. Overexpression of SMAD5 promoted the proliferation and osteogenic differentiation of Saos-2 cells and attenuated the inhibitory effect of miR-148a-3p on cell proliferation and osteogenic differentiation. In conclusion, circ_ KIAA0922 facilitated Saos-2 cell proliferation and osteogenic differentiation via the circ_KIAA0922/ miR-148a-3p/ SMAD5 axes in vitro, thus providing insights into the mechanism of osteogenic differentiation by circ_ KIAA0922.

Emerging roles of circular RNAs in osteoporosis

Osteoporosis is one bone disease characterized with skeletal impairment, bone strength reduced and fracture risk enhanced. The regulation processes of bone metabolism are associated with several factors such as mechanical stimulation, epigenetic regulation and hormones. However, the mechanism of osteoporosis remains unsatisfactory. Increasing high‐throughput RNA sequencing and circular RNAs (circRNAs) microarray studies indicated that circRNAs are differentially expressed in osteoporosis. Growing functional studies further pinpointed specific deregulated expressed circRNAs (e.g., circ_28313, circ_0016624, circ_0006393, circ_0076906 and circ_0048211) for their functions involved in bone metabolism, including bone marrow stromal cells (BMSCs) differentiation, proliferation and apoptosis. Moreover, CircRNAs (circ_0002060, Circ_0001275 and Circ_0001445) may be acted as diagnostic biomarkers for osteoporosis. This review discussed recent progresses in the circRNAs expression profiling analyses and their potential functions in regulating BMSCs differentiation, proliferation and apoptosis.

Hsa_circ_0091581 promotes glioma progression by regulating RMI1 via sponging miR-1243-5p

Glioma is a pervasive malignancy and the main cause of cancer-related deaths worldwide. Circular RNA is an important subject of cancer research, and its role and function in glioma are poorly understood. This study demonstrated that hsa_circ_0091581 is upregulated in glioma tissues and cells. The results of the CCK-8, EdU, and transwell assays indicated that hsa_circ_0091581 promotes proliferation, migration, and invasion of glioma cells. The results of the luciferase reporter and RNA immunoprecipitation assays indicated that the mechanism of the effects of hsa_circ_0091581 on glioma cells involves sponging miR-1243-5p to regulate RMI1. The results of the rescue experiments indicated that hsa_circ_0091581 regulates proliferation, migration, and invasion of glioma cells by targeting RMI1 in a miR-1243-5p dependent manner. The results of the nude mice xenograft assays showed that knockdown of hsa_circ_0091581 inhibits glioma growth in vivo. Thus, our study determined the role of hsa_circ_0091581/miR-1243-5p/RMI1 in glioma and suggests that this axis may be a novel therapeutic target in glioma.