Understanding the role of β2AR-signaling on ILC2 differentiation/plasticity and its implications in cancer progression - Project Summary / Abstract: In preclinical models, norepinephrine released by sympathetic nerves during chronic stress have been demonstrated to promote an immunosuppressive tumor microenvironment (TME) through activation of the β2- adrenergic receptor (β2AR) on various cells including immune cells. This sequence of events could be detrimental to the treatment outcome in cancer patients who are experiencing increased levels of stress. Innate lymphoid cells (ILCs), specifically type II ILCs (ILC2s), have been demonstrated as a small but critical cell population within the TME. However, there is little known about the mechanisms that regulate ILC plasticity and function in the TME. Even though ILC2s express high levels of β2AR, how stress impacts ILC2 activity within the TME is not yet known. In new preliminary data, we have observed a correlation between increased ILC2s and decreased tumor volume in knock out mice lacking the β2AR. Furthermore, our data suggests a shift in ILC2 plasticity toward an anti-tumor phenotype upon loss of β2AR signaling by single-cell RNA sequencing. Therefore, we hypothesize that β2AR signaling activated by chronic stress drives the immunosuppressive function of ILC2s, suppressing the anti-tumor immune response within the tumor microenvironment. We will interrogate the role β2AR signaling plays as a rheostat in ILC development and plasticity into the helper ILC subsets by the two aims proposed here. In Aim 1, we will determine the effect of β2AR signaling on common lymphoid progenitors (CLPs) differentiation into ILC2s and ILC2 plasticity. Utilizing in vitro cultures of wildtype and β2AR-/- CLPs and ILC2s with a β-AR agonist treatment, we will analyze the changes in ILC subset ratios due to β2AR signaling. We will also elucidate the molecular mechanism by which these changes occur using both targeted and high-throughput methodologies. In Aim 2, we will determine the impact of β2AR signaling on ILC2-mediated tumor progression using IL-5creβ2-ARfl/fl conditional knockout mice. The changes in the TME and tumor growth in mice with a conditional β2AR knock out in ILC2 will be analyzed using spectral flow cytometry. Overall, this project will utilize in vitro and in vivo models and other state-of-the-art techniques to understand how chronic stress through β2- AR signaling hampers effective ant-tumor immune response in tumor microenvironment.
