Neoantigens, which are derived from tumour-specific protein-coding mutations, are exempt from central tolerance, can generate robust immune responses1,2 and can function as bona fide antigens that facilitate tumour rejection3. Here we demonstrate that a strategy that uses multi-epitope, personalized neoantigen vaccination, which has previously been tested in patients with high-risk melanoma4–6, is feasible for tumours such as glioblastoma, which typically have a relatively low mutation load1,7 and an immunologically ‘cold’ tumour microenvironment8. We used personalized neoantigen-targeting vaccines to immunize patients newly diagnosed with glioblastoma following surgical resection and conventional radiotherapy in a phase I/Ib study. Patients who did not receive dexamethasone—a highly potent corticosteroid that is frequently prescribed to treat cerebral oedema in patients with glioblastoma—generated circulating polyfunctional neoantigen-specific CD4+ and CD8+ T cell responses that were enriched in a memory phenotype and showed an increase in the number of tumour-infiltrating T cells. Using single-cell T cell receptor analysis, we provide evidence that neoantigen-specific T cells from the peripheral blood can migrate into an intracranial glioblastoma tumour. Neoantigen-targeting vaccines thus have the potential to favourably alter the immune milieu of glioblastoma.

Gliomas with histone H3 lysine27-to-methionine mutations (H3K27M-glioma) arise primarily in the midline of the central nervous system of young children, suggesting a cooperation between genetics and cellular context in tumorigenesis. Although the genetics of H3K27M-glioma are well characterized, their cellular architecture remains uncharted. We performed single-cell RNA sequencing in 3321 cells from six primary H3K27M-glioma and matched models. We found that H3K27M-glioma primarily contain cells that resemble oligodendrocyte precursor cells (OPC-like), whereas more differentiated malignant cells are a minority. OPC-like cells exhibit greater proliferation and tumor-propagating potential than their more differentiated counterparts and are at least in part sustained by signaling. Our study characterizes oncogenic and developmental programs in H3K27M-glioma at single-cell resolution and across genetic subclones, suggesting potential therapeutic targets in this disease.

The impact of alterations in intestinal microbiota on microbial metabolites and on disease processes, such as graft-versus-host disease (GVHD), is not known. Here we performed unbiased analysis to identify novel alterations in gastrointestinal microbiota-derived short chain fatty acids (SCFA) after allogeneic bone marrow transplant (allo-BMT). Alterations in the amounts of only one SCFA, butyrate, were observed only within the intestinal tissue. The reduced butyrate in CD326+ intestinal epithelial cells (IECs) after allo-BMT resulted in decreased histone acetylation, which was restored upon local administration of exogenous butyrate. Butyrate restoration improved IEC junctional integrity, decreased apoptosis, and mitigated GVHD. Furthermore, alteration of the indigenous microbiota with 17 rationally selected strains of high butyrate producing Clostridia also decreased GVHD. These data demonstrate a heretofore unrecognized role of microbial metabolites and suggest that local and specific alteration of microbial metabolites has direct salutary effects on GVHD target tissues and can mitigate its severity.

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Summary Ependymoma is a heterogeneous entity of central nervous system tumors with well-established molecular groups. Here, we apply single-cell RNA sequencing to analyze ependymomas across molecular groups and anatomic locations to investigate their intratumoral heterogeneity and developmental origins. Ependymomas are composed of a cellular hierarchy initiating from undifferentiated populations, which undergo impaired differentiation toward three lineages of neuronal-glial fate specification. While prognostically favorable groups of ependymoma predominantly harbor differentiated cells, aggressive groups are enriched for undifferentiated cell populations. The delineated transcriptomic signatures correlate with patient survival and define molecular dependencies for targeted treatment approaches. Taken together, our analyses reveal a developmental hierarchy underlying ependymomas relevant to biological and clinical behavior.

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• There is a role for the posttranslational modification, neddylation, in regulation of immune responses mediated by dendritic cells.• A role for neddylation in NF-kB signaling in dendritic cells was identified.Posttranslational protein modifications (PTMs) are necessary for cells to function properly. The role of PTMs in regulating immune responses, specifically those mediated by dendritic cells (DCs), which are critical for both innate and adaptive immunity, is not well understood. Utilizing multiple but complementary approaches, we determined the role of an important but less understood type of PTM, namely, neddylation, in regulating DC functions. Inhibition of neddylation suppressed the release of proinflammatory cytokines by DCs in response to Toll-like receptor, nucleotide oligomerization domain-like receptor, and noninfectious CD40L stimulation. These effects were more profound than those mediated by the proteasome inhibitor bortezomib or a commonly used antiinflammatory agent, dexamethasone. Targeting neddylation also suppressed the ability of DCs to stimulate murine allogeneic T cells in vitro and in vivo and human allogeneic T-cell responses in vitro. Mechanistic studies demonstrated that inhibition of neddylation reduced both canonical and noncanonical nuclear factor-kB (NF-kB) activity. Neddylation inhibition prevented the degradation of inhibitor-kB and thus reduced the translocation and activation of NF-kB, but without perturbation of the mitogen-activated protein kinase/extracellular signal-regulated kinase pathway. Thus, blocking neddylation could be a novel strategy for mitigating immune-mediated disease processes. (Blood. 2013;122(12):2062-2073

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