Atlas of the aging mouse colon

Colon cancer is one of the leading causes of death within the western world and is linked to the aging of the colon. The disease presents differently between men and women, developing in different parts of the colon and often with a different morphology. The colonic epithelium is a rapidly renewing tissue, tasked with absorption of water and nutrients, interacting with a wide array of intestinal microbes. The gut-associated lymphoid tissue houses the majority of all immune cells. These immune cells interact with and help regulate the activity of epithelial cells. However, not much is known whether compartment-specific changes occur during aging and how said changes could impact the epithelium. Here we show that both epithelial and immune cells differ significantly between colonic compartments and experience age-related changes, with the possible causal interactions. We found a shift in the absorptive-secretory cell balance, the decrease in colonocytes possibly linked to age-associated malabsorption and intestinal disturbances. We demonstrate marked changes in the aging of the immune cells with regard to populations and interactions with epithelial cells, linking aged immune cell produced cytokines (Ifn-?, Il1B) and the aging of colonic epithelium, which lines up with observations of inflammation causing or exacerbating age-associated gut disfunctions, such as colon cancer. Our results provide new insights into the normal and age-associated states of the colon. We anticipate our work will provide a foundation for further inquiry not only into diseases of the colon (even outside the realm of aging research) but developmental research as well. Overall design: Single-cell RNA seq on epithelial and immune cells from the mouse colon