Biology subjects

Heimberger, A. B.

Publications and source records attributed to Heimberger, A. B..

10 recordsLinked to original sources

bioRxiv2026

Myeloid-targeted RNA nanotherapeutics rewire cholesterol metabolism to unleash anti-tumor immunity in glioblastoma

Tumor-associated myeloid cells (TAMCs) dominate the glioblastoma (GBM) microenvironment and suppress anti-tumor immunity. Here, we identify cholesterol efflux via ABCA1 as a targetable metabolic checkpoint controlling TAMC immunosuppression in GBM. Reprogramming TAMC cholesterol metabolism using TAMC-targeting lipid nanoparticle encapsulating ABCA1 siRNA (ABCA1 LNP) converts TAMCs into potent antigen-presenting cells with enhanced pro-inflammatory activity and antigen-presenting capacity, thereby inducing T cell activation, expansion, and tumor infiltration. Mechanistically, ABCA1 blockade induces cholesterol accumulation in TAMC membranes, promoting lipid raft formation and enhancing MHC-I-mediated antigen presentation. In multiple preclinical GBM models, ABCA1 LNP treatment dramatically induces T cell priming, extends animal survival, and overcomes GBM resistance to radiotherapy and immune checkpoint therapy. This efficacy was well-maintained in stem-like and recurrent GBM models, GBM patient specimens, and a renal cell carcinoma model. Altogether, our work identifies cholesterol efflux as a targetable metabolic vulnerability in TAMCs to overcome therapy resistance in myeloid-rich, immunologically "cold" tumors.

immunology↗

bioRxiv2026

Murine modeling of IDH-mutant 1p/19q-codeleted oligodendroglioma reveals genotype specific phenotypes

Oligodendroglioma is a primary central nervous system tumor classified by the presence of isocitrate dehydrogenase (IDH) mutations and codeletion of 1p/19q. Here we describe the generation of an IDH-mutant 1p/19q-codeleted oligodendroglioma mouse model using in utero electroporation. We identified IDH1R132H, PIK3CAE545K, CicKO, Fubp1KO and Cdkn2aKO as the optimal combination (termed OligoCdkn2a) to drive fully penetrant tumors that histologically resemble human grade II/III IDH-mutant, 1p/19q-codeleted oligodendroglioma. Replacing Cdkn2a with Trp53 loss in this mouse model shifted tumor histology towards high grade astrocytoma. OligoCdkn2a tumors displayed metabolic and transcriptional changes associated with IDH and CIC mutations, and single cell sequencing identified a bias towards oligodendrocyte differentiation compared to an IDH wild-type glioblastoma mouse model. OligoCdkn2a tumors represent the first mouse model system to recapitulate the genetic, histological and transcriptional features of human IDH-mutant 1p/19q-codeleted oligodendrogliomas, offering a platform to further dissect tumor biology and test new therapeutic strategies.

cancer biology↗

bioRxiv2025

Microglial Fructose Metabolism Is Essential for Glioblastoma Growth

Glioblastoma (GBM) is most common and aggressive primary brain tumor in adults, for which standard of care hasnt changed in twenty years. GBM tumor associated macrophages (TAMCs), consisting of infiltrating myeloid cells from the periphery and resident microglia cells, are pro-tumorigenic, promoting tumor growth. Fructose is one of the most abundant metabolites in the GBM tumor microenvironment (TME), as well as in the healthy central nervous system (CNS). In the CNS and GBM, microglia are the predominant expressors of the fructose transporter GLUT5. Mice lacking the GLUT5 transporter (GLUT5-KO) survive significantly longer after orthotopic implantation of two glioma cell lines than wildtype mice, which is not due to dietary fructose or peripherally derived TAMCs. Investigation of the TME showed that GLUT5-KO mice have more highly activated and inflammatory innate and adaptive immune compartments. Microglia cultured in fructose have a decreased phagocytic ability and exhibit decreased inflammatory capacity due to the polyol pathway promoting redox homeostasis.

cancer biology↗

bioRxiv2025

IL-6 underlies microenvironment immunosuppression and resistance to therapy in glioblastoma

The glioblastoma tumor immune microenvironment (TIME) is an immunosuppressive barrier to therapy that encumbers glioblastoma responses to immune checkpoint inhibition (ICI). Immunosuppressive cytokines, pro-tumor myeloid cells, and exhausted T-cells are hallmarks of the glioblastoma TIME. Here we integrate spatial and single-cell analyses of patient-matched human glioblastoma samples before and after ICI with genetic, immunologic, single-cell, and pharmacologic studies in preclinical models to reveal that interleukin-6 (IL-6) inhibition reprograms the glioblastoma TIME to sensitize mouse glioblastoma to ICI and radiotherapy. Rare human glioblastoma patients who achieve clinical responses to ICI have lower pre-treatment IL-6 levels compared to glioblastomas who do not respond to ICI. Immune stimulatory gene therapy suppresses IL-6 tumor levels in preclinical murine models of glioblastoma. Furthermore, survival was longer in Il-6 knockout mice with orthotopic SB28 glioblastoma relative to wild-type mice. IL-6 blockade with a neutralizing antibody transiently sensitizes mouse glioblastoma to anti-PD-1 by increasing MHCII+ monocytes, CD103+ migratory dendritic cells (DCs), CD11b+ conventional DCs, and effector CD8+ T cells, and decreasing immunosuppressive Tregs. To translate these findings to a combination treatment strategy for recurrent glioblastoma patients, we show that IL-6 blockade plus ICI durably sensitizes mouse glioblastoma to high-dose radiotherapy.

cancer biology↗

bioRxiv2025

High Dimensional Proteomic Multiplex Imaging of the Central Nervous System Using the COMET(TM) System

Sequential multiplex methodologies such as Akoya CODEX, Miltenyi MACSima, Rarecyte Orion, and others require modification of the antibodies by conjugation to an oligo or a specific fluorophore which means the use of off-the-shelf reagents is not possible. Modifications of these antibodies are typically performed via reduction chemistry and thus require verification and validation post-modification. Fixed panels are therefore developed due to various limitations including spectral overlap that creates spectral unmixing issues, steric hindrance, harsh antibody removal, and tissue degradation throughout the labeling. As such, a complex interrogation evaluating multiple study hypotheses and/or endpoints requires the development of sequential panels, reconstruction, and realignment of the tissue that necessitate a z-stack strategy. Standardized antibody panels are typically fixed and require substantial validation efforts to modify a single target and thus do not evolve with the pace of research interests. To increase the throughput of profiling cells within the human central nervous system (CNS), we developed and validated a CNS-specific library with an associated analysis platform using the newly developed Lunaphore COMETTM platform. The COMETTM is an automated staining/imaging instrument integrating a reagent deck for staining buffers and off-the-shelf label-free primary antibodies and fluorophore-labeled secondary antibodies, which feed into a circular plate holding up to 4 slides that are automatically imaged in microscope-operated control software. For this study, standard formalin fixed paraffin embedded histology slides are used. However, the COMET is capable of imaging fresh-frozen samples using specialized settings. Our methodologies address an unmet need in the neuroscience field while leveraging prior developmental efforts in the domain of immunology spatial profiling. Cataloging and validating a large series of antibodies on the COMET along with developing CNS autofluorescence management strategies while optimizing standard operating procedures have allowed for the visualization at the subcellular level. Forty analytes can be used to analyze one specimen which has clinical utility in cases in which the CNS can only be sampled by biopsy. CNS biopsies, depending on the anatomical location, can have limited available volume to a degree that requires prioritization and restriction to select analysis. In-depth bioinformatic imaging analysis can be done using standard bioinformatic tools and software such as Visiopharm(R). These results establish a general framework for imaging and quantifying cell populations and networks within the CNS while providing the scientific community with standard operating procedures.

bioinformatics↗

bioRxiv2023

NOTCH3 drives meningioma tumorigenesis and resistance to radiotherapy

Meningiomas are the most common primary intracranial tumors1-3. Treatments for patients with meningiomas are limited to surgery and radiotherapy, and systemic therapies remain ineffective or experimental4,5. Resistance to radiotherapy is common in high-grade meningiomas6, and the cell types and signaling mechanisms driving meningioma tumorigenesis or resistance to radiotherapy are incompletely understood. Here we report NOTCH3 drives meningioma tumorigenesis and resistance to radiotherapy and find NOTCH3+ meningioma mural cells are conserved across meningiomas from humans, dogs, and mice. NOTCH3+ cells are restricted to the perivascular niche during meningeal development and homeostasis and in low-grade meningiomas but are expressed throughout high-grade meningiomas that are resistant to radiotherapy. Integrating single-cell transcriptomics with lineage tracing and imaging approaches across mouse genetic and xenograft models, we show NOTCH3 drives tumor initiating capacity, cell proliferation, angiogenesis, and resistance to radiotherapy to increase meningioma growth and reduce survival. An antibody stabilizing the extracellular negative regulatory region of NOTCH37,8 blocks meningioma tumorigenesis and sensitizes meningiomas to radiotherapy, reducing tumor growth and improving survival in preclinical models. In summary, our results identify a conserved cell type and signaling mechanism that underlie meningioma tumorigenesis and resistance to radiotherapy, revealing a new therapeutic vulnerability to treat meningiomas that are resistant to standard interventions.

cancer biology↗

bioRxiv2022

Immune Contexture of Isocitrate Dehydrogenase stratified Human Gliomas

The brain tumor immune microenvironment (TIME) continuously evolves during glioma progression, but only a limited view of a highly complex glioma associated immune contexture across isocitrate dehydrogenase mutation (IDH) classified gliomas is known. Herein, we present an unprecedentedly comprehensive view of myeloid and lymphoid cell type diversity based on our single cell RNA sequencing and spectral cytometry-based interrogation of tumor-associated leukocytes from fifty-five IDH stratified primary and recurrent human gliomas and three non-glioma brains. Our analyses revealed twenty-two myeloid and lymphoid cell types within and across glioma subtypes. Glioma severity correlated with microglial attrition concomitant with a continuum of invading monocyte-derived microglia-like and macrophages amongst other infiltrating conventional T and NK lymphocytes and unconventional mucosa associated invariant T (MAIT) cells. Specifically, certain microglial and monocyte-derived subpopulations were associated with antigen presentation gene modules, akin to cross-presenting dendritic cells (DCs). Furthermore, we identified phagocytosis and antigen presentation gene modules enriched in Triggering receptor expressed on myeloid (TREM)-2+ cells as a putative anti-glioma axis. Accelerated glioma growth was observed in Trem2 deficient mice implanted with CT2A glioma cells affirming the anti-glioma role of TREM2+ myeloid cells. In addition to providing a comprehensive landscape of glioma-specific immune contexture, our investigations discover TREM2 as a novel immunotherapy target for brain malignancies.

immunology↗

bioRxiv2020

Immune landscape of a genetically-engineered murine model of glioma relative to human glioma by single-cell sequencing

BackgroundThis study focuses on the evaluation of intratumoral immune infiltrates of the Qk/trp53/Pten (QPP) triple-knockout mouse model of glioblastoma with the purpose of establishing its relevance compared to the human disease. This included an analysis at the single cell level, of immune cells composition in both spontaneous and implanted mouse tumors and of samples obtained from human tumor resections. MethodsWe analyzed a cohort of fifteen spontaneous QPP mice, nine implanted QPP mice and 10 glioma patients by standard immune profiling methods such as IHC. Of those, we analyzed three spontaneous QPP mice, three implanted QPP mice, and 10 glioma patients by single cell RNA sequencing. ResultsIn the QPP samples we identified a predominantly myeloid cell population of monocytes, macrophages, and microglia, with minor populations of T, B, and NK cells. When comparing spontaneous and implanted mouse samples, we found that there were more neutrophil, T and NKT cells in the implanted model. In human samples, most of the lymphoid and myeloid compartments were immunosuppressive. While the complexity of the myeloid cell populations is preserved between the QPP model and the human disease, we observed significantly more immune-stimulatory populations in the implanted mouse model. ConclusionsWe found that, despite differences at the subpopulation level, the immunosuppressive nature of the immune system in glioma, is recapitulated in our mouse model. Although we observed differences in the proportions of immune infiltrates derived from the spontaneous and implanted mouse models and in LGG compared to GBM, the major constituents are present in all cases and these differences may be caused by various etiological or pathogenic influences on tumor-immune interactions. Key PointsO_LINew GBM mouse model for immunotherapy C_LIO_LISingle cell profiling of the immune systems in human and mouse GBM C_LI

cancer biology↗

bioRxiv2019

CD8+ T-cell-mediated immunoediting influences genomic evolution and immune evasion in murine gliomas

Cancer immunoediting shapes tumor progression by the selection of tumor cell variants that can evade immune recognition. Given the immune evasion and intra-tumor heterogeneity intrinsic to gliomas, we hypothesized that CD8+ T-cells mediate immunoediting in these tumors. We evaluated glioma progression in the absence of CD8+ T-cells by depleting this immune cell population in transgenic murine gliomas. Upon transplantation, gliomas that developed in the absence of CD8+ T-cells engrafted poorly in recipients with intact immunity but engrafted well in those with CD8+ T-cell depletion. Gliomas developed in absence of CD8+ T-cells exhibited increased chromosomal instability, MAPK signaling, gene fusions, and macrophage/microglial infiltration. MAPK activation correlated with macrophage/microglial recruitment in this model and in the human disease. Our results indicate that CD8+ T-cells mediate immunoediting during gliomagenesis, influencing the genomic stability of glioma and its microenvironment, leading to immune evasion.\n\nSignificanceImmune evasion renders cancer resistant to anti-tumoral immunity. Therapeutic intervention often fails for gliomas because of the plasticity of tumor cell variants that resist immune surveillance. Our results demonstrate a mechanism of immune evasion in gliomas that derives from CD8+ T-cells during the development and progression of this disease.

cancer biology↗

bioRxiv2019

Comparative molecular life history of spontaneous canine and human gliomas

Sporadic gliomas in companion dogs provide a window on the interaction between tumorigenic mechanisms and host environment. We compared the molecular profiles of canine gliomas with those of human pediatric and adult gliomas to characterize evolutionarily conserved mammalian mutational processes in gliomagenesis. Employing whole genome-, exome-, transcriptome-and methylation-sequencing of 81 canine gliomas, we found alterations shared between canine and human gliomas such as the receptor tyrosine kinases, p53 and cell cycle pathways, and IDH1 R132. Canine gliomas showed high similarity with human pediatric gliomas per robust aneuploidy, mutational rates, relative timing of mutations, and DNA methylation patterns. Our cross-species comparative genomic analysis provides unique insights into glioma etiology and the chronology of glioma-causing somatic alterations.\n\nSignificanceDiffuse gliomas are the most common malignant brain tumors, with high-grade tumors carrying a dismal prognosis. Preclinical models have proven themselves as poor predictors of clinical efficacy. Spontaneous glioma in dogs provides an attractive alternative model, because of their comparable tumor microenvironment and tumor life history. We determined the similarities and differences between human and canine gliomas through genomic profiling, and leveraged our datasets to identify conserved somatic drivers, mutational processes and temporal ordering of somatic glioma events across species. We show that canine gliomas resemble human gliomas at (epi-)genetic levels and are more reminiscent of pediatric than adult disease, thus rationalizing sporadic canine glioma as a preclinical model tailored to measuring treatment efficacies in patients with canine or human glioma.

cancer biology↗