A Conserved Bicycle Model for Circadian Clock Control of Membrane Excitability.

Circadian clocks regulate membrane excitability in master pacemaker neurons to control daily rhythms of sleep and wake. Here, we find that two distinctly timed electrical drives collaborate to impose rhythmicity on Drosophila clock neurons. In the morning, a voltage-independent sodium conductance via the NA/NALCN ion channel depolarizes these neurons. This current is driven by the rhythmic expression of NCA localization factor-1, linking the molecular clock to ion channel function. In the evening, basal potassium currents peak to silence clock neurons. Remarkably, daily antiphase cycles of sodium and potassium currents also drive mouse clock neuron rhythms. Thus, we reveal an evolutionarily ancient strategy for the neural mechanisms that govern daily sleep and wake.

miR-9a minimizes the phenotypic impact of genomic diversity by buffering a transcription factor.

Gene expression has to withstand stochastic, environmental, and genomic perturbations. For example, in the latter case, 0.5%-1% of the human genome is typically variable between any two unrelated individuals. Such diversity might create problematic variability in the activity of gene regulatory networks and, ultimately, in cell behaviors. Using multigenerational selection experiments, we find that for the Drosophila proneural network, the effect of genomic diversity is dampened by miR-9a-mediated regulation of senseless expression. Reducing miR-9a regulation of the Senseless transcription factor frees the genomic landscape to exert greater phenotypic influence. Whole-genome sequencing identified genomic loci that potentially exert such effects. A larger set of sequence variants, including variants within proneural network genes, exhibits these characteristics when miR-9a concentration is reduced. These findings reveal that microRNA-target interactions may be a key mechanism by which the impact of genomic diversity on cell behavior is dampened.

A nondegenerate code of deleterious variants in Mendelian loci contributes to complex disease risk.

Although countless highly penetrant variants have been associated with Mendelian disorders, the genetic etiologies underlying complex diseases remain largely unresolved. By mining the medical records of over 110 million patients, we examine the extent to which Mendelian variation contributes to complex disease risk. We detect thousands of associations between Mendelian and complex diseases, revealing a nondegenerate, phenotypic code that links each complex disorder to a unique collection of Mendelian loci. Using genome-wide association results, we demonstrate that common variants associated with complex diseases are enriched in the genes indicated by this "Mendelian code." Finally, we detect hundreds of comorbidity associations among Mendelian disorders, and we use probabilistic genetic modeling to demonstrate that Mendelian variants likely contribute nonadditively to the risk for a subset of complex diseases. Overall, this study illustrates a complementary approach for mapping complex disease loci and provides unique predictions concerning the etiologies of specific diseases.

Expanded encyclopaedias of DNA elements in the human and mouse genomes.

The human and mouse genomes contain instructions that specify RNAs and proteins and govern the timing, magnitude, and cellular context of their production. To better delineate these elements, phase III of the Encyclopedia of DNA Elements (ENCODE) Project has expanded analysis of the cell and tissue repertoires of RNA transcription, chromatin structure and modification, DNA methylation, chromatin looping, and occupancy by transcription factors and RNA-binding proteins. Here we summarize these efforts, which have produced 5,992 new experimental datasets, including systematic determinations across mouse fetal development. All data are available through the ENCODE data portal (https://www.encodeproject.org), including phase II ENCODE1 and Roadmap Epigenomics2 data. We have developed a registry of 926,535 human and 339,815 mouse candidate cis-regulatory elements, covering 7.9 and 3.4% of their respective genomes, by integrating selected datatypes associated with gene regulation, and constructed a web-based server (SCREEN; http://screen.encodeproject.org) to provide flexible, user-defined access to this resource. Collectively, the ENCODE data and registry provide an expansive resource for the scientific community to build a better understanding of the organization and function of the human and mouse genomes.

Genetic regulation of human brain proteome reveals proteins implicated in psychiatric disorders.

Psychiatric disorders are highly heritable yet polygenic, potentially involving hundreds of risk genes. Genome-wide association studies have identified hundreds of genomic susceptibility loci with susceptibility to psychiatric disorders; however, the contribution of these loci to the underlying psychopathology and etiology remains elusive. Here we generated deep human brain proteomics data by quantifying 11,608 proteins across 268 subjects using 11-plex tandem mass tag coupled with two-dimensional liquid chromatography-tandem mass spectrometry. Our analysis revealed 788 cis-acting protein quantitative trait loci associated with the expression of 883 proteins at a genome-wide false discovery rate <5%. In contrast to expression at the transcript level and complex diseases that are found to be mainly influenced by noncoding variants, we found protein expression level tends to be regulated by non-synonymous variants. We also provided evidence of 76 shared regulatory signals between gene expression and protein abundance. Mediation analysis revealed that for most (88%) of the colocalized genes, the expression levels of their corresponding proteins are regulated by cis-pQTLs via gene transcription. Using summary data-based Mendelian randomization analysis, we identified 4 proteins and 19 genes that are causally associated with schizophrenia. We further integrated multiple omics data with network analysis to prioritize candidate genes for schizophrenia risk loci. Collectively, our findings underscore the potential of proteome-wide linkage analysis in gaining mechanistic insights into the pathogenesis of psychiatric disorders.

Nuclear receptors in cancer - uncovering new and evolving roles through genomic analysis.

Nuclear receptors (NRs) have historically been at the forefront of cancer research, where they are known to act as critical regulators of disease. They also serve as biomarkers for tumour subclassification and targets for hormone therapy. However, most tumour types express extensive repertoires of NRs, whose interactions provide multiple paths for disease progression and offer potentially untapped mechanisms for therapeutic interventions. Recently, next-generation sequencing technologies have provided genome-wide insights into the complex interplay of NR transcriptional networks and their contribution to the development and progression of cancer. These findings have altered the traditional understanding of NR activities in oncogenesis.

Genomic antagonism between retinoic acid and estrogen signaling in breast cancer.

Retinoic acid (RA) triggers antiproliferative effects in tumor cells, and therefore RA and its synthetic analogs have great potential as anticarcinogenic agents. Retinoic acid receptors (RARs) mediate RA effects by directly regulating gene expression. To define the genetic network regulated by RARs in breast cancer, we identified RAR genomic targets using chromatin immunoprecipitation and expression analysis. We found that RAR binding throughout the genome is highly coincident with estrogen receptor alpha (ERalpha) binding, resulting in a widespread crosstalk of RA and estrogen signaling to antagonistically regulate breast cancer-associated genes. ERalpha- and RAR-binding sites appear to be coevolved on a large scale throughout the human genome, often resulting in competitive binding activity at nearby or overlapping cis-regulatory elements. The highly coordinated intersection between these two critical nuclear hormone receptor signaling pathways provides a global mechanism for balancing gene expression output via local regulatory interactions dispersed throughout the genome.

Metabolic Regulation of Gene Expression by Histone Lysine ß-Hydroxybutyrylation.

Here we report the identification and verification of a ß-hydroxybutyrate-derived protein modification, lysine ß-hydroxybutyrylation (Kbhb), as a new type of histone mark. Histone Kbhb marks are dramatically induced in response to elevated ß-hydroxybutyrate levels in cultured cells and in livers from mice subjected to prolonged fasting or streptozotocin-induced diabetic ketoacidosis. In total, we identified 44 histone Kbhb sites, a figure comparable to the known number of histone acetylation sites. By ChIP-seq and RNA-seq analysis, we demonstrate that histone Kbhb is a mark enriched in active gene promoters and that the increased H3K9bhb levels that occur during starvation are associated with genes upregulated in starvation-responsive metabolic pathways. Histone ß-hydroxybutyrylation thus represents a new epigenetic regulatory mark that couples metabolism to gene expression, offering a new avenue to study chromatin regulation and diverse functions of ß-hydroxybutyrate in the context of important human pathophysiological states, including diabetes, epilepsy, and neoplasia.

Atypical cutaneous manifestations of methicillin resistant Staphylococcus aureus infections in two immunocompetent pediatric patients: Case reports and review of the literature.

Although many clinical variants of Staphylococcus aureus infection are well-recognized, atypical presentations may mimic other conditions. We describe two cases of atypical S. aureus infections in pediatric patients: a S. aureus infection presenting with a vesicopustular rash mimicking varicella zoster virus and a case of multifocal panniculitis. Both of these cases were specifically caused by methicillin-resistant S. aureus (MRSA). Additional cases of atypical S. aureus infections and presenting features from the current literature are also discussed.

Molecular profiling of a real-world breast cancer cohort with genetically inferred ancestries reveals actionable tumor biology differences between European ancestry and African ancestry patient populations.

BACKGROUND: Endocrine-resistant HR+/HER2- breast cancer (BC) and triple-negative BC (TNBC) are of interest for molecularly informed treatment due to their aggressive natures and limited treatment profiles. Patients of African Ancestry (AA) experience higher rates of TNBC and mortality than European Ancestry (EA) patients, despite lower overall BC incidence. Here, we compare the molecular landscapes of AA and EA patients with HR+/HER2- BC and TNBC in a real-world cohort to promote equity in precision oncology by illuminating the heterogeneity of potentially druggable genomic and transcriptomic pathways. METHODS: De-identified records from patients with TNBC or HR+/HER2- BC in the Tempus Database were randomly selected (N = 5000), with most having stage IV disease. Mutations, gene expression, and transcriptional signatures were evaluated from next-generation sequencing data. Genetic ancestry was estimated from DNA-seq. Differences in mutational prevalence, gene expression, and transcriptional signatures between AA and EA were compared. EA patients were used as the reference population for log fold-changes (logFC) in expression. RESULTS: After applying inclusion criteria, 3433 samples were evaluated (n = 623 AA and n = 2810 EA). Observed patterns of dysregulated pathways demonstrated significant heterogeneity among the two groups. Notably, PIK3CA mutations were significantly lower in AA HR+/HER2- tumors (AA = 34% vs. EA = 42%, P < 0.05) and the overall cohort (AA = 28% vs. EA = 37%, P = 2.08e-05). Conversely, KMT2C mutation was significantly more frequent in AA than EA TNBC (23% vs. 12%, P < 0.05) and HR+/HER2- (24% vs. 15%, P = 3e-03) tumors. Across all subtypes and stages, over 8000 genes were differentially expressed between the two ancestral groups including RPL10 (logFC = 2.26, P = 1.70e-162), HSPA1A (logFC = - 2.73, P = 2.43e-49), ATRX (logFC = - 1.93, P = 5.89e-83), and NUTM2F (logFC = 2.28, P = 3.22e-196). Ten differentially expressed gene sets were identified among stage IV HR+/HER2- tumors, of which four were considered relevant to BC treatment and were significantly enriched in EA: ERBB2_UP.V1_UP (P = 3.95e-06), LTE2_UP.V1_UP (P = 2.90e-05), HALLMARK_FATTY_ACID_METABOLISM (P = 0.0073), and HALLMARK_ANDROGEN_RESPONSE (P = 0.0074). CONCLUSIONS: We observed significant differences in mutational spectra, gene expression, and relevant transcriptional signatures between patients with genetically determined African and European ancestries, particularly within the HR+/HER2- BC and TNBC subtypes. These findings could guide future development of treatment strategies by providing opportunities for biomarker-informed research and, ultimately, clinical decisions for precision oncology care in diverse populations.

Distinct genomic features in a retrospective cohort of mucosal, acral, and vulvovaginal melanomas.

BACKGROUND: Compared with sun-exposed melanomas, less is known regarding the pathogenesis of sun-protected melanomas. Sun-protected melanomas share many epidemiologic factors, but their genetic heterogeneity is not well studied. OBJECTIVE: We investigated the genomic profile of acral, mucosal, and vulvovaginal melanomas. We hypothesize that mucosal melanomas, recognized for their uniquely aggressive clinical behavior, have distinct genomic features. METHODS: We performed whole transcriptome messenger RNA and DNA (1711 genes) sequencing, messenger RNA expression profiling, tumor mutational burden, ultraviolet signature, and copy number variants analysis on 29 volar/digital acral, 7 mucosal, and 6 vulvovaginal melanomas. RESULTS: There was significant genetic heterogeneity, particularly in acral melanomas, with 36% having BRAF alterations, whereas other melanomas had none (P = .0159). Nonzero ultraviolet signatures were more frequent in acral melanomas, suggesting greater ultraviolet involvement. Mucosal melanomas formed a distinct group with increased expression of cell cycle and proliferation genes. Various targetable aberrations were identified, such as AURKA and ERBB2, in mucosal and acral melanomas, respectively. LIMITATIONS: The sample size was a small. CONCLUSION: There is significant genetic heterogeneity among sun-protected melanomas. Mucosal melanomas have upregulation in cell cycle and proliferation genes, which may explain their aggressive behavior. Ultraviolet radiation plays some role in a subset of acral but not other melanomas.

Integration of temporal and spatial patterning generates neural diversity.

In the Drosophila optic lobes, 800 retinotopically organized columns in the medulla act as functional units for processing visual information. The medulla contains over 80 types of neuron, which belong to two classes: uni-columnar neurons have a stoichiometry of one per column, while multi-columnar neurons contact multiple columns. Here we show that combinatorial inputs from temporal and spatial axes generate this neuronal diversity: all neuroblasts switch fates over time to produce different neurons; the neuroepithelium that generates neuroblasts is also subdivided into six compartments by the expression of specific factors. Uni-columnar neurons are produced in all spatial compartments independently of spatial input; they innervate the neuropil where they are generated. Multi-columnar neurons are generated in smaller numbers in restricted compartments and require spatial input; the majority of their cell bodies subsequently move to cover the entire medulla. The selective integration of spatial inputs by a fixed temporal neuroblast cascade thus acts as a powerful mechanism for generating neural diversity, regulating stoichiometry and the formation of retinotopy.

To mock or not: a comprehensive comparison of mock IP and DNA input for ChIP-seq.

Chromatin immunoprecipitation (IP) followed by sequencing (ChIP-seq) is the gold standard to detect transcription-factor (TF) binding sites in the genome. Its success depends on appropriate controls removing systematic biases. The predominantly used controls, i.e. DNA input, correct for uneven sonication, but not for nonspecific interactions of the IP antibody. Another type of controls, 'mock' IP, corrects for both of the issues, but is not widely used because it is considered susceptible to technical noise. The tradeoff between the two control types has not been investigated systematically. Therefore, we generated comparable DNA input and mock IP experiments. Because mock IPs contain only nonspecific interactions, the sites predicted from them using DNA input indicate the spurious-site abundance. This abundance is highly correlated with the 'genomic activity' (e.g. chromatin openness). In particular, compared to cell lines, complex samples such as whole organisms have more spurious sites-probably because they contain multiple cell types, resulting in more expressed genes and more open chromatin. Consequently, DNA input and mock IP controls performed similarly for cell lines, whereas for complex samples, mock IP substantially reduced the number of spurious sites. However, DNA input is still informative; thus, we developed a simple framework integrating both controls, improving binding site detection.

Nerve autofluorescence in near-ultraviolet light markedly enhances nerve visualization in vivo.

BACKGROUND: During surgery, surgeons must accurately localize nerves to avoid injuring them. Recently, we have discovered that nerves fluoresce in near-ultraviolet light (NUV) light. The aims of the current study were to determine the extent to which nerves fluoresce more brightly than background and vascular structures in NUV light, and identify the NUV intensity at which nerves are most distinguishable from other tissues. METHODS: We exposed sciatic nerves within the posterior thigh in five 250-300 gm Wistar rats, then observed them at four different NUV intensity levels: 20%, 35%, 50%, and 100%. Brightness of fluorescence was measured by fluorescence spectroscopy, quantified as a fluorescence score using Image-J software, and statistically compared between nerves, background, and both an artery and vein by unpaired Student's t tests with Bonferroni adjustment to accommodate multiple comparisons. Sensitivity, specificity, and accuracy were calculated for each NUV intensity. RESULTS: At 20, 35, 50, and 100% NUV intensity, fluorescence scores for nerves versus background tissues were 117.4 versus 40.0, 225.8 versus 88.0, 250.6 versus 121.4, and 252.8 versus 169.4, respectively (all p < 0.001). Fluorescence scores plateaued at 50% NUV intensity for nerves, but continued to rise for background. At 35%, 50%, and 100% NUV intensity, a fluorescence score of 200 was 100% sensitive, specific, and accurate identifying nerves. At 100 NUV intensity, artery and vein scores were 61.8 and 60.0, both dramatically lower than for nerves (p < 0.001). CONCLUSIONS: At all NUV intensities ≥ 35%, a fluorescence score of 200 is 100% accurate distinguishing nerves from other anatomical structures in vivo.

Nerve autofluorescence under near-ultraviolet light: cutting-edge technology for intra-operative neural tissue visualization in 17 patients.

BACKGROUND: Nerve visualization and the identification of other neural tissues during surgery is crucial for numerous reasons, including the prevention of iatrogenic nerve and neural structure injury and facilitation of nerve repair. However, current methods of intra-operative nerve detection are generally expensive, unproven, and/or technically challenging. Recently, we have documented, in both in vivo animal models and ex vivo human tissue, that nerves autofluorescence when viewed in near-ultraviolet light (NUV). In this paper, we describe our use of nerve autofluorescence to facilitate the visualization of nerves and other neural tissues intra-operatively in 17 patients undergoing a range of surgical procedures. METHODS: Employing the same prototype axon imaging system previously documented to markedly enhance nerve visualization in both in vivo animal and ex vivo human models, surgical fields were observed in 17 patients under both white and NUV light during parotid tumor resection (n = 3), thyroid tumor resection (n = 7), and surgery for peripheral nerve and spinal tumors and injury (n = 7). RESULTS: In all 17 patients, the intra-operative use of the imaging system both was feasible and markedly enhanced the localization of all neural tissues throughout their course within the surgical field. All 17 procedures were successful and devoid of any peri-operative complications or post-operative neurological deficits. CONCLUSIONS: Intra-operatively visualizing auto-fluorescent peripheral nerves and other neural tissues under NUV light is feasible in human patients across a range of clinical scenarios and appears to appreciably enhance nerve and other neural tissue visualization. Controlled studies to explore this technology further are needed.

The Drosophila MLR COMPASS complex is essential for programming cis-regulatory information and maintaining epigenetic memory during development.

The MLR COMPASS complex monomethylates H3K4 that serves to epigenetically mark transcriptional enhancers to drive proper gene expression during animal development. Chromatin enrichment analyses of the Drosophila MLR complex reveals dynamic association with promoters and enhancers in embryos with late stage enrichments biased toward both active and poised enhancers. RNAi depletion of the Cmi (also known as Lpt) subunit that contains the chromatin binding PHD finger domains attenuates enhancer functions, but unexpectedly results in inappropriate enhancer activation during stages when hormone responsive enhancers are poised, revealing critical epigenetic roles involved in both the activation and repression of enhancers depending on developmental context. Cmi is necessary for robust H3K4 monomethylation and H3K27 acetylation that mark active enhancers, but not for the chromatin binding of Trr, the MLR methyltransferase. Our data reveal two likely major regulatory modes of MLR function, contributions to enhancer commissioning in early embryogenesis and bookmarking enhancers to enable rapid transcriptional re-activation at subsequent developmental stages.

Infectious vaccine-derived rubella viruses emerge, persist, and evolve in cutaneous granulomas of children with primary immunodeficiencies.

Rubella viruses (RV) have been found in an association with granulomas in children with primary immune deficiencies (PID). Here, we report the recovery and characterization of infectious immunodeficiency-related vaccine-derived rubella viruses (iVDRV) from diagnostic skin biopsies of four patients. Sequence evolution within PID hosts was studied by comparison of the complete genomic sequences of the iVDRVs with the genome of the vaccine virus RA27/3. The degree of divergence of each iVDRV correlated with the duration of persistence indicating continuous intrahost evolution. The evolution rates for synonymous and nonsynonymous substitutions were estimated to be 5.7 x 10-3 subs/site/year and 8.9 x 10-4 subs/site/year, respectively. Mutational spectra and signatures indicated a major role for APOBEC cytidine deaminases and a secondary role for ADAR adenosine deaminases in generating diversity of iVDRVs. The distributions of mutations across the genes and 3D hotspots for amino acid substitutions in the E1 glycoprotein identified regions that may be under positive selective pressure. Quasispecies diversity was higher in granulomas than in recovered infectious iVDRVs. Growth properties of iVDRVs were assessed in WI-38 fibroblast cultures. None of the iVDRV isolates showed complete reversion to wild type phenotype but the replicative and persistence characteristics of iVDRVs were different from those of the RA27/3 vaccine strain, making predictions of iVDRV transmissibility and teratogenicity difficult. However, detection of iVDRV RNA in nasopharyngeal specimen and poor neutralization of some iVDRV strains by sera from vaccinated persons suggests possible public health risks associated with iVDRV carriers. Detection of IgM antibody to RV in sera of two out of three patients may be a marker of virus persistence, potentially useful for identifying patients with iVDRV before development of lesions. Studies of the evolutionary dynamics of iVDRV during persistence will contribute to development of infection control strategies and antiviral therapies.

DRAMS: A tool to detect and re-align mixed-up samples for integrative studies of multi-omics data.

Studies of complex disorders benefit from integrative analyses of multiple omics data. Yet, sample mix-ups frequently occur in multi-omics studies, weakening statistical power and risking false findings. Accurately aligning sample information, genotype, and corresponding omics data is critical for integrative analyses. We developed DRAMS (https://github.com/Yi-Jiang/DRAMS) to Detect and Re-Align Mixed-up Samples to address the sample mix-up problem. It uses a logistic regression model followed by a modified topological sorting algorithm to identify the potential true IDs based on data relationships of multi-omics. According to tests using simulated data, the more types of omics data used or the smaller the proportion of mix-ups, the better that DRAMS performs. Applying DRAMS to real data from the PsychENCODE BrainGVEX project, we detected and corrected 201 (12.5% of total data generated) mix-ups. Of the 21 mix-ups involving errors of racial identity, DRAMS re-assigned all data to the correct racial group in the 1000 Genomes project. In doing so, quantitative trait loci (QTL) (FDR<0.01) increased by an average of 1.62-fold. The use of DRAMS in multi-omics studies will strengthen statistical power of the study and improve quality of the results. Even though very limited studies have multi-omics data in place, we expect such data will increase quickly with the needs of DRAMS.

Nerve spectroscopy: understanding peripheral nerve autofluorescence through photodynamics.

BACKGROUND: Being able to accurately identify sensory and motor nerves is crucial during surgical procedures to prevent nerve injury. We aimed to (1) evaluate the feasibility of performing peripheral human nerve visualization utilizing nerves' own autofluorescence in an ex-vivo model; (2) compare the effect of three different nerve fiber fixation methods on the intensity of fluorescence, indicated as the intensity ratio; and (3) similarly compare three different excitation ranges. METHODS: Samples from various human peripheral nerves were selected postoperatively. Nerve fibers were divided into three groups: Group A nerve fibers were washed with a physiologic solution; Group B nerve fibers were fixated with formaldehyde for 6 h first, and then washed with a physiologic solution; Group C nerve fibers were fixated with formaldehyde for six hours, but not washed afterwards. An Olympus IX83 inverted microscope was used for close-up image evaluation. Nerve fibers were exposed to white-light wavelength spectrums for a specific time frame prior to visualization under three different filters-Filter 1-LF405-B-OMF Semrock; Filter 2-U-MGFP; Filter 3-U-MRFPHQ Olympus, with excitation ranges of 390-440, 460-480, and 535-555, respectively. The fluorescence intensity of all images was subsequently analyzed using Image-J Software, and results compared by analysis of variance (ANOVA). RESULTS: The intensity ratios observed with Filter 1 failed to distinguish the different nerve fiber groups (p = 0.39). Conversely, the intensity ratios seen under Filters 2 and 3 varied significantly between the three nerve-fiber groups (p = 0.021, p = 0.030, respectively). The overall intensity of measurements was greater with Filter 1 than Filter 3 (p < 0.05); however, all nerves were well visualized by all filters. CONCLUSION: The current results on ex vivo peripheral nerve fiber autofluorescence suggest that peripheral nerve fiber autofluorescence intensity does not greatly depend upon the excitation wavelength or fixation methods used in an ex vivo setting. Implications for future nerve-sparing surgery are discussed.