TNF-α Suppresses Apelin Receptor Expression in Mouse Quadriceps Femoris-Derived Cells
Expression of the apelin receptor, APJ, in skeletal muscle (SM) is known to decrease with age, but the underlying mechanism remains unclear. Increased tumor necrosis factor (TNF)-α levels are observed in SM with age and are associated with muscle atrophy. To investigate the possible interconnection...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-07-01
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| Series: | Current Issues in Molecular Biology |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1467-3045/44/7/217 |
| Summary: | Expression of the apelin receptor, APJ, in skeletal muscle (SM) is known to decrease with age, but the underlying mechanism remains unclear. Increased tumor necrosis factor (TNF)-α levels are observed in SM with age and are associated with muscle atrophy. To investigate the possible interconnection between TNF-α elevation and APJ reduction with aging, we investigated the effect of TNF-α on APJ expression in cells derived from the quadriceps femoris of C57BL/6J mice. Expression of <i>Tnfa</i> and <i>Apj</i> in the quadriceps femoris was compared between 4- (young) and 24-month-old (old) C57BL/6J mice (<i>n</i> = 10 each) using qPCR. Additionally, APJ-positive cells and TNF-α protein were analyzed by flow cytometry and Western blotting, respectively. Further, quadricep-derived cells were exposed to 0 (control) or 25 ng/mL TNF-α, and the effect on <i>Apj</i> expression was examined by qRT-PCR. <i>Apj</i> expression and the ratio of APJ-positive cells among quadricep cells were significantly lower in old compared to young mice. In contrast, levels of <i>Tnfa</i> mRNA and TNF-α protein were significantly elevated in old compared to young mice. Exposing young and old derived quadricep cells to TNF-α for 8 and 24 h caused <i>Apj</i> levels to significantly decrease. TNF-α suppresses APJ expression in muscle cells in vitro. The increase in TNF-α observed in SM with age may induce a decrease in APJ expression. |
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| ISSN: | 1467-3037 1467-3045 |