53 research outputs found

    Subependymal giant cell astrocytomas are characterized by mTORC1 hyperactivation, a very low somatic mutation rate, and a unique gene expression profile

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    Subependymal giant-cell astrocytomas (SEGAs) are slow-growing brain tumors that are a hallmark feature seen in 5–10% of patients with Tuberous Sclerosis Complex (TSC). Though histologically benign, they can cause serious neurologic symptoms, leading to death if untreated. SEGAs consistently show biallelic loss of TSC1 or TSC2. Herein, we aimed to define other somatic events beyond TSC1/TSC2 loss and identify potential transcriptional drivers that contribute to SEGA formation. Paired tumor-normal whole-exome sequencing was performed on 21 resected SEGAs from 20 TSC patients. Pathogenic variants in TSC1/TSC2 were identified in 19/21 (90%) SEGAs. Copy neutral loss of heterozygosity (size range: 2.2–46 Mb) was seen in 76% (16/21) of SEGAs (44% chr9q and 56% chr16p). An average of 1.4 other somatic variants (range 0–7) per tumor were identified, unlikely of pathogenic significance. Whole transcriptome RNA-sequencing analyses revealed 190 common differentially expressed genes in SEGA (n = 16, 13 from a prior study) in pairwise comparison to each of: low grade diffuse gliomas (n = 530) and glioblastoma (n = 171) from The Cancer Genome Atlas (TCGA) consortium, ganglioglioma (n = 10), TSC cortical tubers (n = 15), and multiple normal tissues. Among these, homeobox transcription factors (TFs) HMX3, HMX2, VAX1, SIX3; and TFs IRF6 and EOMES were all expressed >12-fold higher in SEGAs (FDR/q-value < 0.05). Immunohistochemistry supported the specificity of IRF6, VAX1, SIX3 for SEGAs in comparison to other tumor entities and normal brain. We conclude that SEGAs have an extremely low somatic mutation rate, suggesting that TSC1/TSC2 loss is sufficient to drive tumor growth. The unique and highly expressed SEGA-specific TFs likely reflect the neuroepithelial cell of origin, and may also contribute to the transcriptional and epigenetic state that enables SEGA growth following two-hit loss of TSC1 or TSC2 and mTORC1 activation

    Trispecific antibody targeting HIV-1 and T cells activates and eliminates latently-infected cells in HIV/SHIV infections.

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    Agents that can simultaneously activate latent HIV, increase immune activation and enhance the killing of latently-infected cells represent promising approaches for HIV cure. Here, we develop and evaluate a trispecific antibody (Ab), N6/αCD3-αCD28, that targets three independent proteins: (1) the HIV envelope via the broadly reactive CD4-binding site Ab, N6; (2) the T cell antigen CD3; and (3) the co-stimulatory molecule CD28. We find that the trispecific significantly increases antigen-specific T-cell activation and cytokine release in both CD4 &lt;sup&gt;+&lt;/sup&gt; and CD8 &lt;sup&gt;+&lt;/sup&gt; T cells. Co-culturing CD4 &lt;sup&gt;+&lt;/sup&gt; with autologous CD8 &lt;sup&gt;+&lt;/sup&gt; T cells from ART-suppressed HIV &lt;sup&gt;+&lt;/sup&gt; donors with N6/αCD3-αCD28, results in activation of latently-infected cells and their elimination by activated CD8 &lt;sup&gt;+&lt;/sup&gt; T cells. This trispecific antibody mediates CD4 &lt;sup&gt;+&lt;/sup&gt; and CD8 &lt;sup&gt;+&lt;/sup&gt; T-cell activation in non-human primates and is well tolerated in vivo. This HIV-directed antibody therefore merits further development as a potential intervention for the eradication of latent HIV infection

    Measurement of the inclusive b→τνX branching ratio

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    Oxidative stress, Nox isoforms and complications of diabetes—potential targets for novel therapies

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    Most diabetes-related complications and causes of death arise from cardiovascular disease and end-stage renal disease. Amongst the major complications of diabetes mellitus are retinopathy, neuropathy, nephropathy and accelerated atherosclerosis. Increased bioavailability of reactive oxygen species (ROS) (termed oxidative stress), derived in large part from the NADPH oxidase (Nox) family of free radical producing enzymes, has been demonstrated in experimental and clinical diabetes and has been implicated in the cardiovascular and renal complications of diabetes. The present review focuses on the role of Noxs and oxidative stress in some major complications of diabetes, including nephropathy, retinopathy and atherosclerosis. We also discuss Nox isoforms as potential targets for therapy
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