Engineered lymphatic stroma model applications in central nervous system leukemia

Central nervous system (CNS) involvement frequently occurs in acute lymphoblastic leukemia (ALL), but many questions remain about how leukemia cells access, persist in, and exploit the CNS. The CNS is protected by the meninges, which are fluid-filled membranes that surround the brain. Within the meninges, meningeal lymphatic vessels, located within the dura mater, drain cerebrospinal fluid to the deep cervical lymph nodes for immunosurveillance, providing a potential pathway for leukemia cells to enter or exit the CNS. Here, we utilized tissue engineered models of the meningeal lymphatics and lymph node stroma to probe how leukemia cells interact with these key microenvironments. We first demonstrated that standard-of-care chemotherapeutics can perturb the meningeal lymphatics, particularly lymphatic endothelial cells. Next, we showed that soluble factors from the meningeal lymphatics conferred a modest upward trend in leukemia cell growth, while soluble factors from the lymph node model under flow significantly promoted leukemia cell migration. Finally, we showed that leukemia cells migrate through the lymph node model under both static and flow conditions. Overall, we have demonstrated the feasibility of using engineered lymphatic models to study leukemia cell behavior in the CNS with the goal of expanding the available experimental platforms for understanding CNS metastasis and relapse. Insight Box Leukemia commonly infiltrates the central nervous system (CNS), requiring intensive CNS-directed therapies that are often ineffective and cause both acute and long-term toxicities, especially in pediatric patients. The meningeal lymphatics and the deep cervical lymph nodes constitute a pivotal axis in CNS immunity, facilitating drainage of fluid and waste, and enabling peripheral immune surveillance in response to CNS-derived signals. Here, we employ in vitro models of the meningeal lymphatics and lymph node stroma to examine their crosstalk in influencing leukemia cell growth and migration. These engineered platforms serve as valuable tools for uncovering mechanistic insights into the meningeal-lymph node axis in the context of CNS-leukemia relapse.