Microglial activation in the spinal cord plays a central role in the development and maintenance of chronic pain after a peripheral nerve injury (PNI). There has not yet been a thorough assessment of microglial activation in brain regions associated with pain and reward. To this end, this study uses a mouse model of neuropathic pain in which the left sciatic nerve of male C57Bl/6J mice is loosely constricted (chronic constriction injury) to assess microglial activation in several brain regions 2 weeks after injury, a time point at which pain hypersensitivity is well established. We found significant microglial activation in brain regions associated with sensory pain transmission and affect, including the thalamus, sensory cortex, and amygdala. Activation was consistently most robust in brain regions contralateral to the side of injury. Brain regions not directly involved in either sensory or affective dimensions of pain, such as the motor cortex, did not display microglial activation. This study confirms that PNI induces microglial activation in regions involved with both sensory and affective components of pain. © 2016 Wiley Periodicals, Inc.

This study measured total osmolarity and concentrations of NH(4)(+), NO(3)(-), K(+), soluble carbohydrates, and organic acids in maize seminal roots as a function of distance from the apex, and NH(4)(+) and NO(3)(-) in xylem sap for plants receiving NH(4)(+) or NO(3)(-) as a sole N-source, NH(4)(+) plus NO(3)(-), or no nitrogen at all. The disparity between net deposition rates and net exogenous influx of NH(4)(+) indicated that growing cells imported NH(4)(+) from more mature tissue, whereas more mature root tissues assimilated or translocated a portion of the NH(4)(+) absorbed. Net root NO(3)(-) influx under Ca(NO(3))(2) nutrition was adequate to account for pools found in the growth zone and provided twice as much as was deposited locally throughout the non-growing tissue. In contrast, net root NO(3)(-) influx under NH(4)NO(3) was less than the local deposition rate in the growth zone, indicating that additional NO(3)(-) was imported or metabolically produced. The profile of NO(3)(-) deposition rate in the growth zone, however, was similar for the plants receiving Ca(NO(3))(2) or NH(4)NO(3). These results suggest that NO(3)(-) may serve a major role as an osmoticant for supporting root elongation in the basal part of the growth zone and maintaining root function in the young mature tissues.

Chronic pain attenuates midbrain dopamine (DA) transmission, as evidenced by a decrease in opioid-evoked DA release in the ventral striatum, suggesting that the occurrence of chronic pain impairs reward-related behaviors. However, mechanisms by which pain modifies DA transmission remain elusive. Using in vivo microdialysis and microinjection of drugs into the mesolimbic DA system, we demonstrate in mice and rats that microglial activation in the VTA compromises not only opioid-evoked release of DA, but also other DA-stimulating drugs, such as cocaine. Our data show that loss of stimulated extracellular DA is due to impaired chloride homeostasis in midbrain GABAergic interneurons. Treatment with minocycline or interfering with BDNF signaling restored chloride transport within these neurons and recovered DA-dependent reward behavior. Our findings demonstrate that a peripheral nerve injury causes activated microglia within reward circuitry that result in disruption of dopaminergic signaling and reward behavior. These results have broad implications that are not restricted to the problem of pain, but are also relevant to affective disorders associated with disruption of reward circuitry. Because chronic pain causes glial activation in areas of the CNS important for mood and affect, our findings may translate to other disorders, including anxiety and depression, that demonstrate high comorbidity with chronic pain.

Single-cell genomics enables dissection of tumor heterogeneity and molecular underpinnings of drug response at an unprecedented resolution^1-11. However, broad clinical application of these methods remains challenging, due to several practical and preanalytical challenges that are incompatible with typical clinical care workflows, namely the need for relatively large, fresh tissue inputs. In the present study, we show that multimodal, single-nucleus (sn)RNA/T cell receptor (TCR) sequencing, spatial transcriptomics and whole-genome sequencing (WGS) are feasible from small, frozen tissues that approximate routinely collected clinical specimens (for example, core needle biopsies). Compared with data from sample-matched fresh tissue, we find a similar quality in the biological outputs of snRNA/TCR-seq data, while reducing artifactual signals and compositional biases introduced by fresh tissue processing. Profiling sequentially collected melanoma samples from a patient treated in the KEYNOTE-001 trial¹², we resolved cellular, genomic, spatial and clonotype dynamics that represent molecular patterns of heterogeneous intralesional evolution during anti-programmed cell death protein 1 therapy. To demonstrate applicability to banked biospecimens of rare diseases¹³, we generated a single-cell atlas of uveal melanoma liver metastasis with matched WGS data. These results show that single-cell genomics from archival, clinical specimens is feasible and provides a framework for translating these methods more broadly to the clinical arena.

Functional redundancy shared by paralog genes may afford protection against genetic perturbations, but it can also result in genetic vulnerabilities due to mutual interdependency^1-5. Here, we surveyed genome-scale short hairpin RNA and CRISPR screening data on hundreds of cancer cell lines and identified MAGOH and MAGOHB, core members of the splicing-dependent exon junction complex, as top-ranked paralog dependencies^6-8. MAGOHB is the top gene dependency in cells with hemizygous MAGOH deletion, a pervasive genetic event that frequently occurs due to chromosome 1p loss. Inhibition of MAGOHB in a MAGOH-deleted context compromises viability by globally perturbing alternative splicing and RNA surveillance. Dependency on IPO13, an importin-β receptor that mediates nuclear import of the MAGOH/B-Y14 heterodimer⁹, is highly correlated with dependency on both MAGOH and MAGOHB. Both MAGOHB and IPO13 represent dependencies in murine xenografts with hemizygous MAGOH deletion. Our results identify MAGOH and MAGOHB as reciprocal paralog dependencies across cancer types and suggest a rationale for targeting the MAGOHB-IPO13 axis in cancers with chromosome 1p deletion.

Diatoms are photosynthetic secondary endosymbionts found throughout marine and freshwater environments, and are believed to be responsible for around one-fifth of the primary productivity on Earth. The genome sequence of the marine centric diatom Thalassiosira pseudonana was recently reported, revealing a wealth of information about diatom biology. Here we report the complete genome sequence of the pennate diatom Phaeodactylum tricornutum and compare it with that of T. pseudonana to clarify evolutionary origins, functional significance and ubiquity of these features throughout diatoms. In spite of the fact that the pennate and centric lineages have only been diverging for 90 million years, their genome structures are dramatically different and a substantial fraction of genes (40percent) are not shared by these representatives of the two lineages. Analysis of molecular divergence compared with yeasts and metazoans reveals rapid rates of gene diversification in diatoms. Contributing factors include selective gene family expansions, differential losses and gains of genes and introns, and differential mobilization of transposable elements. Most significantly, we document the presence of hundreds of genes from bacteria. More than 300 of these gene transfers are found in both diatoms, attesting to their ancient origins, and many are likely to provide novel possibilities for metabolite management and for perception of environmental signals. These findings go a long way towards explaining the incredible diversity and success of the diatoms in contemporary oceans.

We conducted comprehensive integrative molecular analyses of the complete set of tumors in The Cancer Genome Atlas (TCGA), consisting of approximately 10,000 specimens and representing 33 types of cancer. We performed molecular clustering using data on chromosome-arm-level aneuploidy, DNA hypermethylation, mRNA, and miRNA expression levels and reverse-phase protein arrays, of which all, except for aneuploidy, revealed clustering primarily organized by histology, tissue type, or anatomic origin. The influence of cell type was evident in DNA-methylation-based clustering, even after excluding sites with known preexisting tissue-type-specific methylation. Integrative clustering further emphasized the dominant role of cell-of-origin patterns. Molecular similarities among histologically or anatomically related cancer types provide a basis for focused pan-cancer analyses, such as pan-gastrointestinal, pan-gynecological, pan-kidney, and pan-squamous cancers, and those related by stemness features, which in turn may inform strategies for future therapeutic development.

Aneuploidy, whole chromosome or chromosome arm imbalance, is a near-universal characteristic of human cancers. In 10,522 cancer genomes from The Cancer Genome Atlas, aneuploidy was correlated with TP53 mutation, somatic mutation rate, and expression of proliferation genes. Aneuploidy was anti-correlated with expression of immune signaling genes, due to decreased leukocyte infiltrates in high-aneuploidy samples. Chromosome arm-level alterations show cancer-specific patterns, including loss of chromosome arm 3p in squamous cancers. We applied genome engineering to delete 3p in lung cells, causing decreased proliferation rescued in part by chromosome 3 duplication. This study defines genomic and phenotypic correlates of cancer aneuploidy and provides an experimental approach to study chromosome arm aneuploidy.

This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing molecular features of squamous cell carcinomas (SCCs) from five sites associated with smoking and/or human papillomavirus (HPV). SCCs harbor 3q, 5p, and other recurrent chromosomal copy-number alterations (CNAs), DNA mutations, and/or aberrant methylation of genes and microRNAs, which are correlated with the expression of multi-gene programs linked to squamous cell stemness, epithelial-to-mesenchymal differentiation, growth, genomic integrity, oxidative damage, death, and inflammation. Low-CNA SCCs tended to be HPV(+) and display hypermethylation with repression of TET1 demethylase and FANCF, previously linked to predisposition to SCC, or harbor mutations affecting CASP8, RAS-MAPK pathways, chromatin modifiers, and immunoregulatory molecules. We uncovered hypomethylation of the alternative promoter that drives expression of the ΔNp63 oncogene and embedded miR944. Co-expression of immune checkpoint, T-regulatory, and Myeloid suppressor cells signatures may explain reduced efficacy of immune therapy. These findings support possibilities for molecular classification and therapeutic approaches.

The Cancer Genome Atlas (TCGA) has catalyzed systematic characterization of diverse genomic alterations underlying human cancers. At this historic junction marking the completion of genomic characterization of over 11,000 tumors from 33 cancer types, we present our current understanding of the molecular processes governing oncogenesis. We illustrate our insights into cancer through synthesis of the findings of the TCGA PanCancer Atlas project on three facets of oncogenesis: (1) somatic driver mutations, germline pathogenic variants, and their interactions in the tumor; (2) the influence of the tumor genome and epigenome on transcriptome and proteome; and (3) the relationship between tumor and the microenvironment, including implications for drugs targeting driver events and immunotherapies. These results will anchor future characterization of rare and common tumor types, primary and relapsed tumors, and cancers across ancestry groups and will guide the deployment of clinical genomic sequencing.