Single-Cell RNA Sequencing Identifies Accumulation Of Fcgr2B + Virtual Memory-Like Cd8 T Cells With Cytotoxic And Inflammatory Potential In Aged Mouse White Adipose Tissue
Our bodies undergo many changes as we age, and one area of increasing interest is how our immune system and fat tissue interact. It’s known that both aging and obesity can lead to inflammation in our fat tissue, which can contribute to various age-related diseases. To understand this better, researchers used a powerful technique called single-cell RNA sequencing, which allows them to examine the genetic activity of individual cells in a tissue.
In a recent study, scientists looked at the fat tissue from young mice, obese mice, and aged mice. They discovered that physiological aging, more so than obesity caused by a high-fat diet, was linked to an increase in a unique type of immune cell known as CD8 T cells. These particular CD8 T cells resemble “virtual memory” cells, meaning they have characteristics of immune cells that are ready to respond to threats, even without prior exposure.
Crucially, these age-associated CD8 T cells, specifically those expressing a marker called Fcgr2b, were found to accumulate in the white fat tissue of older mice. Further investigation showed that these cells have the potential to be both cytotoxic (meaning they can kill other cells) and inflammatory. They produce a molecule called granzyme M, which was demonstrated to induce inflammation in other cell types, like fibroblasts and macrophages. This finding suggests that these specialized immune cells play a significant role in the chronic low-grade inflammation often observed in fat tissue during aging.