There is a critical need to identify mechanisms whereby abnormally regulated lncRNAs in macrophages drive progression of GBM and ways to target these lncRNAs preclinically. Our long-term goal is to accelerate the development of immune therapeutics targeting dysregulated lncRNAs to improve outcomes of GBM patients. Our overall objective for this application is to establish a delivery platform targeting novel GBM-specific lncRNAs that promote tumor progression. Our central hypothesis is that overexpression of lncRNAs in TAMs promote GBM tumor progression and immune suppression and are targetable with nanoparticles. The rationale for the proposed research is that evidence of nanoparticle-based targeting of dysregulated GBM-specific lncRNAs will provide new opportunities for the continued development of novel treatment strategies focused on inhibiting TAM-mediated immune suppression. Aim 1: Identify candidate lncRNAs mediating GBM progression. Our approach will be to perform deep bulk RNASeq of CD14+ cell subsets sorted from single cell suspensions of fresh GBM tissue and compare these to the peripheral blood of GBM patients and normal controls to identify differentially expressed lncRNAs, then use bioinformatic tools to choose lncRNAs that are likely to contribute to GBM immune suppression. Our working hypothesis is that TAMs overexpress lncRNAs associated with promotion of immune suppression in GBM beyond those identified from PBMCs alone. Aim 2. Determine the effect(s) of candidate lncRNA depletion on TAM phenotype and function. Our approach will be to deplete candidate lncRNAs in monocytes using siRNA. We will functionally characterize the response to depletion of these lncRNAs and begin mechanistic characterization of novel lncRNAs from Aim 1. Our working hypothesis is that depleting target lncRNAs will change the phenotype and function of these cells, making them resistant to M2-like polarization by IL-4 and IL-13, maintaining a more immune-stimulating state. Aim 3. Develop lncRNA targeted theranostic nanoparticles for lncRNA depletion in TAMs. Our approach will be to further develop MRI trackable nanoparticles for depletion of our preliminary target lncRNAs and any lncRNAs identified in Aim 1 in our genetically engineered murine model of GBM. Our working hypothesis is that our nanoparticles will deplete M2-like TAMs in the murine tumors and improve survival in this model. Our contribution here is expected to be the identification of novel lncRNAs with functional relevance in GBM TAMs and a translational platform for their delivery in murine models of GBM. These contributions will be significant because they are expected to represent an important next step toward future development and clinical trials of novel immune therapeutics for patients with this devastating brain cancer. The proposed research is innovative, in our opinion, because it represents a substantive departure from the status quo by focusing on discovery of immune-related lncRNAs...