Disrupted FAP-satellite cell communication contribute to maladaptive muscle remodeling in older women

Researchers have discovered that disrupted communication between immune cells and muscle cells contributes to the muscle deterioration often seen in older women. After studying aged skeletal muscle and its recovery from stressors, the team observed that older women have a different response to muscle disuse compared to younger adults.

Utilizing single-nucleus RNA sequencing and experiments with primary muscle cells, the researchers found that older women's muscle cells show a larger transcriptional response following disuse atrophy. This response is driven by satellite cells, which are a key part of the muscle's regenerative process. Satellite cells from older women were found to express higher levels of collagen, a protein that can cause stiffness in muscles.

Additionally, immune cells known as FAPs (fibroblast activation proteins) from older women were seen to be more active, releasing factors that could further hinder muscle recovery. The researchers also noted that when muscle cells from older women were grown in the lab, they showed signs of cellular senescence, a state where cells stop dividing and can contribute to tissue damage.

Furthermore, the immune cells from older women were found to communicate more poorly with muscle cells, potentially disrupting the muscle's ability to repair and remodel itself. Overall, these findings suggest that the way immune cells interact with muscle cells during recovery from muscle disuse is different in older women, and this altered communication may be a factor in the poor muscle remodeling seen in this population.