A Novel Age-Related Circular RNA Circ-ATXN2 Inhibits Proliferation, Promotes Cell Death and Adipogenesis in Rat Adipose Tissue-Derived Stromal Cells

Abstract

Adipose tissue-derived stromal cells are promising candidates investigating the stem cell-related treatment. However, their proportion and utility in the human body decline with time, rendering stem cells incompetent to complete repair processes in vivo. The involvement of circRNAs in the aging process is poorly understood. Rat subcutaneous adipose tissue from 10-week-old and 27-month-old rats were used for hematoxylin and eosin (H and E) staining, TUNEL staining, and circRNA sequencing. Rat adipose tissue-derived stromal cells were cultured and overexpressed with circ-ATXN2. Proliferation was examined using xCELLigence real-time cell analysis, EdU staining, and cell cycle assay. Apoptosis was induced by CoCl2 and examined using flow cytometry. RT-PCR assay and Oil Red O staining were used to measure adipogenesis at 48 h and 14 days, respectively. H and E staining showed that the diameter of adipocytes increased; however, the number of cells decreased in old rats. TUNEL staining showed that the proportion of apoptotic cells was increased in old rats. A total of 4,860 and 4,952 circRNAs was detected in young and old rats, respectively. Among them, 67 circRNAs exhibited divergent expression between the two groups (fold change ≥2, p ≤ 0.05), of which 33 were upregulated (49.3%) and 34 were downregulated (50.7%). The proliferation of circ-ATXN2-overexpressing cells decreased significantly in vitro, which was further validated by xCELLigence real-time cell analysis, EdU staining, and cell cycle assay. Overexpression of circ-ATXN2 significantly increased the total apoptotic rate from 5.78 ± 0.46% to 11.97 ± 1.61%, early apoptotic rate from 1.76 ± 0.22% to 5.50 ± 0.66%, and late apoptosis rate from 4.02 ± 0.25% to 6.47 ± 1.06% in adipose tissue-derived stromal cells. Furthermore, in circ-ATXN2-overexpressing cells, RT-PCR assay revealed that the expression levels of adipose differentiation-related genes PPARγ and CEBP/α were increased and the Oil Red O staining assay showed more lipid droplets. Our study revealed the expression profile of circRNAs in the adipose tissue of old rats. We found a novel age-related circular RNA—circ-ATXN2—that inhibits proliferation and promotes cell death and adipogenesis in rat adipose tissue-derived stromal cells.

CircRNA-5335 Regulates the Differentiation and Proliferation of Sheep Preadipocyte via the miR-125a-3p/STAT3 Pathway

“…CircRNA-Circ-ATXN2 is a new type of age-related circRNA that can inhibit proliferation and promote cell lipogenesis and death in adipose-tissue-derived stromal cells [ 44 ]. CircFUT10 binds to let-7c and targets bovine adipocyte PPARGC1B to promote cell proliferation and inhibit cell differentiation [ 1 ].…”

“…Therefore, we identified circRNA-5335 as a positive regulator of preadipocyte differentiation that has an opposite function to miR-125a-3p and can be interfered with by miR-125a-3p inhibitors. CircRNA-Circ-ATXN2 is a new type of age-related circRNA that can inhibit proliferation and promote cell lipogenesis and death in adipose-tissue-derived stromal cells [44]. CircFUT10 binds to let-7c and targets bovine adipocyte PPARGC1B to promote cell proliferation and inhibit cell differentiation [1].…”

Analysis of Hepatic Lipid Metabolism and Immune Function During the Development of Collagen-Induced Arthritis

“…ATXN2 is a pleiotropic gene linked to various diseases, including diabetes and inflammation ( 44 ). A recent study found that overexpression of circ-ATXN2 promoted adipogenesis in adipose tissue-derived stromal cells ( 45 ). When its activity increased, ATP Binding Cassette Subfamily A Member 1 (ABCA1), a key transporter of cholesterol out of the cell, triggered the metabolism of cholesterol and phospholipids in cells and influenced the process of FA differentiation ( 46 , 47 ).…”

A Novel Circ_Arf3/miR-452-5p/Mbnl1 Axis Regulates Proliferation and Expression of Fibrosis-Related Proteins of Mouse Mesangial Cells Under High Glucose

“… 20 Of interest, miR-452-5p, a frequently dysregulated miRNA in various disorders, 21 , 22 can participate in the modulation of HG-induced levels of immune and antioxidant factors in HK-2 cells. 23 In our preliminary survey for the circRNAs targeted miR-452-5p using online program starbase, we found four circRNAs: circRNA ADP ribosylation factor 3 (circ_Arf3), circRNA nuclear FMR1 interacting protein 2 (circ_Nufip2), circRNA ataxin 2 (circ_Atxn2), and circRNA myosin heavy chain 9 (circ_Myh9) that are closely associated with human disease, 24 , 25 and our data showed that only circ_Arf3 is aberrantly expressed in HG-treated MCs ( Supplementary Figure 1 ). Circ_Arf3 (also called circ_0000650 based on the circRNA ID) is formed by the exonic circularization of Arf3 pre-mRNA.…”