TCR-engineered adoptive cell therapy effectively treats intracranial murine glioblastoma

BACKGROUND: Adoptive cellular therapies with chimeric antigen receptor T cells have revolutionized the treatment of some malignancies but have shown limited efficacy in solid tumors such as glioblastoma and face a scarcity of safe therapeutic targets. As an alternative, T cell receptor (TCR)-engineered cellular therapy against tumor-specific neoantigens has generated significant excitement, but there exist no preclinical systems to rigorously model this approach in glioblastoma. METHODS: We employed single-cell PCR to isolate a TCR specific for the Imp3 RESULTS: We isolated and characterized the 3×1.1C TCR that displayed a high affinity for mImp3 but no wild-type cross-reactivity. To provide a source of mImp3-specific T cells, we generated the MISTIC mouse. In a model of adoptive cellular therapy, the infusion of activated MISTIC T cells resulted in rapid intratumoral infiltration and profound antitumor effects with long-term cures in a majority of GL261-bearing mice. The subset of mice that did not respond to the adoptive cell therapy showed evidence of retained neoantigen expression but intratumoral MISTIC T cell dysfunction. The efficacy of MISTIC T cell therapy was lost in mice bearing a tumor with heterogeneous mImp3 expression, showcasing the barriers to targeted therapy in polyclonal human tumors. CONCLUSIONS: We generated and characterized the first TCR transgenic against an endogenous neoantigen within a preclinical glioma model and demonstrated the therapeutic potential of adoptively transferred neoantigen-specific T cells. The MISTIC mouse provides a powerful novel platform for basic and translational studies of antitumor T-cell responses in glioblastoma

Single-cell profiling of human dura and meningioma reveals cellular meningeal landscape and insights into meningioma immune response

BACKGROUND: Recent investigations of the meninges have highlighted the importance of the dura layer in central nervous system immune surveillance beyond a purely structural role. However, our understanding of the meninges largely stems from the use of pre-clinical models rather than human samples. METHODS: Single-cell RNA sequencing of seven non-tumor-associated human dura samples and six primary meningioma tumor samples (4 matched and 2 non-matched) was performed. Cell type identities, gene expression profiles, and T cell receptor expression were analyzed. Copy number variant (CNV) analysis was performed to identify putative tumor cells and analyze intratumoral CNV heterogeneity. Immunohistochemistry and imaging mass cytometry was performed on selected samples to validate protein expression and reveal spatial localization of select protein markers. RESULTS: In this study, we use single-cell RNA sequencing to perform the first characterization of both non-tumor-associated human dura and primary meningioma samples. First, we reveal a complex immune microenvironment in human dura that is transcriptionally distinct from that of meningioma. In addition, we characterize a functionally diverse and heterogenous landscape of non-immune cells including endothelial cells and fibroblasts. Through imaging mass cytometry, we highlight the spatial relationship among immune cell types and vasculature in non-tumor-associated dura. Utilizing T cell receptor sequencing, we show significant TCR overlap between matched dura and meningioma samples. Finally, we report copy number variant heterogeneity within our meningioma samples. CONCLUSIONS: Our comprehensive investigation of both the immune and non-immune cellular landscapes of human dura and meningioma at single-cell resolution builds upon previously published data in murine models and provides new insight into previously uncharacterized roles of human dura

Dietary Vitamin D and Its Metabolites Non-Genomically Stabilize the Endothelium.

Vitamin D is a known modulator of inflammation. Native dietary vitamin D3 is thought to be bio-inactive, and beneficial vitamin D3 effects are thought to be largely mediated by the metabolite 1,25(OH)2D3. Reduced serum levels of the most commonly measured precursor metabolite, 25(OH)D3, is linked to an increased risk of multiple inflammatory diseases, including: cardiovascular disease, arthritis, multiple sclerosis, and sepsis. Common to all of these diseases is the disruption of endothelial stability and an enhancement of vascular leak. We previously performed an unbiased chemical suppressor screen on a genetic model of vascular instability, and identified cholecalciferol (D3, dietary Vitamin D3) as a factor that had profound and immediate stabilizing and therapeutic effects in that model. In this manuscript we show that the presumed inactive sterol, D3, is actually a potent and general mediator of endothelial stability at physiologically relevant concentrations. We further demonstrate that this phenomenon is apparent in vitamin D3 metabolites 25(OH)D3 and 1,25(OH)2D3, and that the effects are independent of the canonical transcription-mediated vitamin D pathway. Our data suggests the presence of an alternative signaling modality by which D3 acts directly on endothelial cells to prevent vascular leak. The finding that D3 and its metabolites modulate endothelial stability may help explain the clinical correlations between low serum vitamin D levels and the many human diseases with well-described vascular dysfunction phenotypes

D₃ abrogates inflammatory leak in culture and <i>ex</i> vivo.

<p>Monolayers of HMVEC were stimulated with D₃ (10 μM), 7-DHC(10 μM), or 0.5% DMSO (vehicle control) in the presence of inflammatory cytokines: IL-1β (10 ng/mL), TNF-α (2 ng/mL), and LPS (100 ng/mL) in an (<b>A-C</b>) ECIS or (<b>D</b>) transwell leak assay. (<b>E</b>) VEGF-induced leak of a fluorescent reporter in arterioles isolated from wild-type mice fed either standard chow or a D₃-enhanced chow. All panels depict mean ± SEM. * denotes P<0.05, ** denotes P<0.01, and **** denotes P<0.0001.</p

D₃ blocks RHOA and ARF6 activation in destabilized endothelial cells.

<p>Endothelial cells were exposed to 10 μM D₃ or 7-DHC in combination with 2ng/mL TNF-α or IL-1β. Lysates were analyzed for RHOA-GTP and ARF6-GTP levels using appropriate precipitation assays. All graphs depict mean ± SEM. * denotes P<0.05, ** denotes P<0.01, and *** denotes P<0.001.</p

Vitamin D sterol activity.

<p>Graphical models of the different vitamin D3 sterols, their metabolism, and a summary of their normal circulating levels, the minimum active dose for stabilizing the endothelium and doses in which the sterols have been reported to interact with vitamin D receptor [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0140370#pone.0140370.ref029" target="_blank">29</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0140370#pone.0140370.ref051" target="_blank">51</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0140370#pone.0140370.ref052" target="_blank">52</a>]. *Normal circulating levels vary upon many conditions including diet and UV exposure.</p

D₃ stabilizes endothelial cells through a non-genomic mechanism.

<p><b>(A)</b> Endothelial cells were exposed to D₃ or its metabolites for 24 hours and lysates were probed for VDR transcription targets FOX01 and CYP24. Endothelial cells were exposed to D₃ or its metabolites in the presence of inhibitors of transcription (actinomycin D) and translation (cycloheximide) <b>(B, C)</b> and were assessed for transendothelial resistance or VDR target gene expression. All graphs depict mean ± SEM. * denotes P<0.05, and **** denotes P<0.0001. ### denotes P<0.001, and #### denotes P<0.0001 versus the respective control.</p

D₃ promotes VE-cadherin cell-cell junction stability.

<p>(<b>A</b>) Endothelial cells were treated with TNF-α and either 7-DHC or D₃ for the denoted times and lysates were immunoblotted for p731 VE-cadherin or total VE-Cadherin. (<b>B</b>) Endothelial cell monolayers were exposed to the denoted pro-inflammatory cues in the presence of vehicle control, D₃ or 7DHC. Cells were fixed and VE-Cadherin was visualized through immunofluorescent labeling with automated image acquisition and analysis. All graphs depict mean ± SEM. * denotes P<0.05, ** denotes P<0.01, and *** denotes P<0.001.</p