Microenvironmental Rescue of Age-related Cellular Dysfunction in a 3D Bioprinted Mammary Model System - Project Summary During the complex process of cellular and tissue decline due to organismal aging, diseases such as diabetes, neurodegeneration, muscle atrophy, and cancer become commonplace. These diseases each have unique genetic features and targeting them can lead to therapies preserving tissue functions. However, restoration to a youthful state is rare. Thus, it is critical to research and design methods of restorative or preventative treatments to cure these diseases. A major challenge in researching age-related tissue decline is ensuring that the findings reliably predict outcomes at the organismal level. To this end, we and others have demonstrated the powerful regenerative capabilities of the mouse mammary gland during the process of mammary gland biogenesis. When the mouse mammary gland is cleared of nascent epithelial tissues and injected with dispersed mouse mammary epithelial cells or tissue fragments mixed with cancer cells, dysfunctional stem cells, or normal non-mammary stem cells, they are redirected/rescued while functionally contributing to gland regeneration. Other data has demonstrated that cancer cells exposed to the regenerative embryonic environment can also be redirected to a normal functional state. Consistent with this, our preliminary evidence shows that interactions with induced pluripotent stem cells can reduce tumor formation rates of breast cancer cells in mice. These data, coupled with the finding that EVs isolated from pluripotent cells can also promote healing, block senescence, and reduce molecular markers of aging, indicate that cells/tissues can be rejuvenated via exposure to a regenerative environment. However, our understanding of the molecular mechanisms for why this happens is lacking. While the gold standard cleared mammary gland mouse model is an important tool for studying regenerative models, it is difficult to determine molecular mechanisms when used exclusively. To solve this issue our group has designed a low-cost, adaptable 3D bioprinter capable of manufacturing luminal chimeric mammary epithelial organoids in vitro. This tool, in tandem with the mouse mammary gland model system, enables us to ask discreet molecular-driven questions about how regenerative environments and signaling cause their observed effects. We have found that as these regenerative chimeric organoids form in vitro, the exchange of intercellular machinery, such as mitochondria, readily occurs. Here we hypothesize that that the exposure of dysfunctional organoids/tissues to youthful regenerative signaling reverses age-related decline through intercellular transfer of molecular machinery, including mitochondria. To test this hypothesis, we aim to 1: Determine the molecular effect of regenerative intercellular transfer on aged/senescent cells and 2: Determine the molecular effect of intercellular transfer on cancer cells. These data will allow us to understand a critical aspect of the rejuvenating effects of exposure to regenerative environments and, thus, broaden our capabilities to develop downstream clinical treatments to prevent or cure many age-related diseases.
