Publications by authors named "Root D"

Conditioned suppression is a useful paradigm for measuring learned avoidance. In most conditioned suppression studies, forward conditioning is used where a cue predicts an aversive stimulus. However, backward conditioning, in which an aversive stimulus predicts a cue, provides unique insights into learned avoidance due to its influence on both conditioned excitation and inhibition.

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The bed nucleus of the stria terminalis (BNST) is involved in feeding, reward, aversion, and anxiety-like behavior. We identify BNST neurons defined by the expression of vesicular glutamate transporter 3, VGluT3. VGluT3 neurons were localized to anteromedial BNST, were molecularly distinct from accumbal VGluT3 neurons, and co-express vesicular GABA transporter (VGaT).

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Background: Atypical teratoid rhabdoid tumors (ATRT) are incurable high-grade pediatric brain tumors. Despite intensive research efforts, the prognosis for ATRT patients under currently established treatment protocols is poor. While novel therapeutic strategies are urgently needed, the generation of molecular-driven treatment concepts is a challenge mainly due to the absence of actionable genetic alterations.

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To dissect variant-function relationships in the KRAS oncoprotein, we performed deep mutational scanning (DMS) screens for both wild-type and KRAS mutant alleles. We defined the spectrum of oncogenic potential for nearly all possible variants, identifying several novel transforming alleles and elucidating a model to describe the frequency of mutations in human cancer as a function of transforming potential, mutational probability, and tissue-specific mutational signatures. Biochemical and structural analyses of variants identified in a KRAS second-site suppressor DMS screen revealed that attenuation of oncogenic KRAS can be mediated by protein instability and conformational rigidity, resulting in reduced binding affinity to effector proteins, such as RAF and PI3-kinases, or reduced SOS-mediated nucleotide exchange activity.

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Article Synopsis
  • A population of neurons in the ventral tegmental area (VTA) co-transmit two neurotransmitters, glutamate and GABA, but their inputs and functions are not fully understood.
  • Using advanced tracing techniques in mice, researchers discovered that these neurons receive diverse inputs from various brain regions, with significant inputs from the superior colliculus and lateral hypothalamus.
  • Optical activation of these inputs revealed that lateral hypothalamus involvement leads to active behavior, while superior colliculus stimulation results in brief activation and freezing behavior, indicating the complex integration of signals by VTA neurons related to motivation and behavior.
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Loss-of-function germline () tumor suppressor mutations cause VHL disease, which predisposes individuals to kidney cancer, hemangioblastomas, and paragangliomas. The risk that a given VHL disease family will manifest some or all these tumor types is profoundly influenced by the allele it carries. For example, almost all VHL disease families that develop paraganglioma have missense mutations.

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Sonic hedgehog subgroup of medulloblastoma (SHH-MB) is characterized by aberrant activation of the SHH signaling pathway. An inhibition of the positive SHH regulator Smoothened (SMO) has demonstrated promising clinical efficacy. Yet, primary and acquired resistance to SMO inhibitors limit their efficacy.

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Biliary tract cancers (BTCs) are a group of deadly malignancies encompassing intrahepatic and extrahepatic cholangiocarcinoma, gallbladder carcinoma, and ampullary carcinoma. Here, we present the integrative analysis of 63 BTC cell lines via multi-omics clustering and genome- scale CRISPR screens, providing a platform to illuminate BTC biology and inform therapeutic development. We identify dependencies broadly enriched in BTC compared to other cancers as well as dependencies selective to the anatomic subtypes.

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Triple-negative breast cancer (TNBC) is responsible for a disproportionate number of breast cancer patient deaths due to extensive molecular heterogeneity, high recurrence rates, and lack of targeted therapies. Dysregulation of the phosphoinositide 3-kinase (PI3K)/AKT pathway occurs in approximately 50% of TNBC patients. Here, we performed a genome-wide CRISPR/Cas9 screen with PI3Kα and AKT inhibitors to find targetable synthetic lethalities in TNBC.

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Ventral tegmental area (VTA) glutamatergic neurons participate in reward, aversion, drug-seeking, and stress. Subsets of VTA VGluT2+ neurons are capable of co-transmitting glutamate and GABA (VGluT2+VGaT+ neurons), transmitting glutamate without GABA (VGluT2+VGaT- neurons), or co-transmitting glutamate and dopamine (VGluT2+TH+ neurons), but whether these molecularly distinct subpopulations show behavior-related differences is not wholly understood. We identified that neuronal activity of each VGluT2+ subpopulation is sensitive to reward value but signaled this in different ways.

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Neuroinflammation is a pathological feature of many neurodegenerative diseases, including Alzheimer's disease (AD) and amyotrophic lateral sclerosis (ALS), raising the possibility of common therapeutic targets. We previously established that cytoplasmic double-stranded RNA (cdsRNA) is spatially coincident with cytoplasmic pTDP-43 inclusions in neurons of patients with C9ORF72-mediated ALS. CdsRNA triggers a type-I interferon (IFN-I)-based innate immune response in human neural cells, resulting in their death.

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Background: Genome-wide functional screening using the CRISPR-Cas9 system is a powerful tool to uncover tumor-specific and common genetic dependencies across cancer cell lines. Current CRISPR-Cas9 knockout libraries, however, primarily target protein-coding genes. This limits functional genomics-based investigations of miRNA function.

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Reducing disparities is vital for equitable access to precision treatments in cancer. Socioenvironmental factors are a major driver of disparities, but differences in genetic variation likely also contribute. The impact of genetic ancestry on prioritization of cancer targets in drug discovery pipelines has not been systematically explored due to the absence of pre-clinical data at the appropriate scale.

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The identification of genetic and chemical perturbations with similar impacts on cell morphology can elucidate compounds' mechanisms of action or novel regulators of genetic pathways. Research on methods for identifying such similarities has lagged due to a lack of carefully designed and well-annotated image sets of cells treated with chemical and genetic perturbations. Here we create such a Resource dataset, CPJUMP1, in which each perturbed gene's product is a known target of at least two chemical compounds in the dataset.

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Wilms tumor (WT) is the most common renal malignancy of childhood. Despite improvements in the overall survival, relapse occurs in ~15% of patients with favorable histology WT (FHWT). Half of these patients will succumb to their disease.

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The epidermal growth factor receptor, EGFR, is frequently activated in lung cancer and glioblastoma by genomic alterations including missense mutations. The different mutation spectra in these diseases are reflected in divergent responses to EGFR inhibition: significant patient benefit in lung cancer, but limited in glioblastoma. Here, we report a comprehensive mutational analysis of EGFR function.

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The measurement of antidrug antibodies (ADA) in nonclinical studies provides limited value because the formation and incidence of nonclinical ADA does not translate to clinical experience. The formation and presence of ADA in nonclinical species can, however, correlate to reduced drug exposure and safety observations including vasculitis and immune complex disease. Generic ADA methods for humanized monoclonal antibody biotherapeutics mitigate the need to develop bespoke ADA methods during nonclinical drug development.

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A hallmark of high-risk childhood medulloblastoma is the dysregulation of RNA translation. Currently, it is unknown whether medulloblastoma dysregulates the translation of putatively oncogenic non-canonical open reading frames (ORFs). To address this question, we performed ribosome profiling of 32 medulloblastoma tissues and cell lines and observed widespread non-canonical ORF translation.

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Somatic copy number gains are pervasive across cancer types, yet their roles in oncogenesis are insufficiently evaluated. This inadequacy is partly due to copy gains spanning large chromosomal regions, obscuring causal loci. Here, we employed organoid modeling to evaluate candidate oncogenic loci identified via integrative computational analysis of extreme copy gains overlapping with extreme expression dysregulation in The Cancer Genome Atlas.

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(Mtb) has evolved to be exquisitely adapted to survive within host macrophages. The capacity to damage the phagosomal membrane has emerged as central to Mtb virulence. While Mtb factors driving membrane damage have been described, host factors that repair that damage to contain the pathogen remain largely unknown.

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Article Synopsis
  • Leiomyosarcoma (LMS) is a challenging cancer with poor response to standard chemotherapy (under 30%), largely due to its chromosomal instability and defects in DNA repair mechanisms caused by mutations in TP53 and RB1.
  • Researchers conducted targeted sequencing and genome-wide screens on LMS samples to find specific therapeutic targets that could exploit these genetic vulnerabilities.
  • They discovered that combining DNA-PK inhibitors with low doses of doxorubicin showed promising synergistic effects in reducing LMS growth in both lab models and mouse studies, presenting a potential new treatment strategy without significant toxicity.
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Article Synopsis
  • NUT carcinoma is an aggressive cancer driven by the BRD4-NUT fusion oncoprotein, but treatments using BET bromodomain inhibitors (BETi) alone have limited effectiveness.
  • The study shows that inhibiting EZH2, a protein that silences tumor suppressor genes, with a drug called tazemetostat, effectively blocks the growth of NUT carcinoma cells.
  • Combining EZH2 and BET inhibitors leads to stronger anti-cancer effects, blocking tumor growth and prolonging survival in models, highlighting a new strategy for treating NUT carcinoma based on targeting epigenetic regulation.
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Foraging is a universal behaviour that has co-evolved with predation pressure. We investigated the role of the bed nucleus of the stria terminalis (BNST) GABA neurons in robotic and live predator threat processing and their consequences in post-threat encounter foraging. Both robotic and live predator interactions increased BNST GABA neuron activity.

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