The rockefeller university

Nucleosome positioning and stability affect gene regulation in eukaryotic chromatin. Histone H2A.Z is an evolutionally conserved histone variant that forms mobile and unstable nucleosomes in vivo and in vitro. In the present study, we reconstituted nucleosomes containing human H2A.Z.1 mutants, in which the N-terminal or C-terminal half of H2A.Z.1 was replaced by the corresponding canonical H2A region. We found that the N-terminal portion of H2A.Z.1 is involved in flexible nucleosome positioning, whereas the C-terminal portion leads to weak H2A.Z.1-H2B association in the nucleosome. These results indicate that the N-terminal and C-terminal portions are independently responsible for the H2A.Z.1 nucleosome characteristics.

G-protein-gated inward rectifier potassium (GIRK) channels are regulated by G proteins and PIP2. Here, using cryo-EM single particle analysis we describe the equilibrium ensemble of structures of neuronal GIRK2 as a function of the C8-PIP2 concentration. We find that PIP2 shifts the equilibrium between two distinguishable structures of neuronal GIRK (GIRK2), extended and docked, towards the docked form. In the docked form the cytoplasmic domain, to which G(beta gamma) binds, becomes accessible to the cytoplasmic membrane surface where G(beta gamma) resides. Furthermore, PIP2 binding reshapes the G(beta gamma) binding surface on the cytoplasmic domain, preparing it to receive G(beta gamma). We find that cardiac GIRK (GIRK1/4) can also exist in both extended and docked conformations. These findings lead us to conclude that PIP2 influences GIRK channels in a structurally similar manner to Kir2.2 channels. In Kir2.2 channels, the PIP2-induced conformational changes open the pore. In GIRK channels, they prepare the channel for activation by G(beta gamma).

Intravenous administration of anti-alpha(4)beta(7) monoclonal antibody in macaques decreases simian immunodeficiency virus (SIV) vaginal infection and reduces gut SIV loads. Because of potential side effects of systemic administration, a prophylactic strategy based on mucosal administration of anti-alpha(4)beta(7) antibody may be safer and more effective. With this in mind, we developed a novel intravaginal formulation consisting of anti-alpha(4)beta(7) monoclonal antibody-conjugated nanoparticles (NPs) loaded in a 1% hydroxyethylcellulose (HEC) gel (NP-alpha(4)beta(7) gel). When intravaginally administered as a single dose in a rhesus macaque model, the formulation preferentially bound to CD4(+) or CD3(+) T cells expressing high levels of alpha(4)beta(7), and occupied similar to 40% of alpha(4)beta(7)expressed by these subsets and similar to 25% of all cells expressing alpha(4)beta(7). Blocking of the alpha(4)beta(7) was restricted to the vaginal tract without any changes detected systemically.

N-6-methyladenosine is the most prominent RNA modification in mammals. Here, we study mouse skin embryogenesis to tackle m6A's functions and physiological importance. We first landscape the m6A modifications on skin epithelial progenitor mRNAs. Contrasting with in vivo ribosomal profiling, we unearth a correlation between m6A modification in coding sequences and enhanced translation, particularly of key morphogenetic signaling pathways. Tapping physiological relevance, we show that m6A loss profoundly alters these cues and perturbs cellular fate choices and tissue architecture in all skin lineages. By single-cell transcriptomics and bioinformatics, both signaling and canonical translation pathways show significant downregulation after m6A loss. Interestingly, however, many highly m6A-modified mRNAs are markedly upregulated upon m6A loss, and they encode RNA-methylation, RNA-processing and RNA-metabolism factors. Together, our findings suggest that m6A functions to enhance translation of key morphogenetic regulators, while also destabilizing sentinel mRNAs that are primed to activate rescue pathways when m6A levels drop.

This year is a plague year. The COVID-19 pandemic, caused by the coronavirus SARS-CoV-2, is burning across the globe as we anxiously await an effective vaccine or drug to control it. Another plague, of a much older kind — one that is not curable with vaccines or medicine — is currently raging in Africa (Fig. 1) and the Middle East. Seasons of unusually heavy rains, driven by climate change (see go.nature.com/3fchnrm), have created population explosions of swarming desert locusts (Schistocerca gregaria). Swarms can contain billions of insects and cover hundreds of square kilometres. These insects strip vegetation and crops, threatening the precarious existence of subsistence farmers and contributing to food insecurity in vulnerable regions. The only effective weapon for fighting such locust plagues is the aerial spraying of pesticides, but the swarms are fast-moving and unpredictable, and spraying devastates beneficial insects.

Dear Editor, Brodalumab1 is an interleukin‐17 receptor A antagonist previously used in an open‐label cohort study dosed every 2 weeks (E2W) in hidradenitis suppurativa (HS).2 Brodalumab E2W demonstrated high clinical efficacy [at week 12, 10 of 10 had Hidradenitis Suppurativa Clinical Response (HiSCR)]. However, participants with draining tunnels were observed to demonstrate cyclical response2 (rapid reduction in acute symptoms, with slow re‐emergence of tunnel drainage and pain). We hypothesized that weekly dosing might provide better disease control.

The unexpected seroconversion of sentinel mice in our facility to murine T lymphotrophic virus (MTLV) positivity led to our identification of a novel murine astrovirus that we designated murine astrovirus 2 (MuAstV-2). During our investigation, MuAstV-2 was found to be a contaminant of the T helper cell line (D10.G4.1) that was used to generate the MTLV antigen that we included in the multiplex fluorometric immunoassay (MFIA) that we used for sentinel screening. We eventually determined that cross-reactivity with the astrovirus generated a positive result in the MTLV assay. A confirmatory immunofluorometric assay (IFA) using the same MTLV-infected cell line yielded a similar result. However, the use of antigen prepared from MTLV-infected neonatal mouse thymus did not reproduce a positive result, leading us to suspect that the seroreactivity we had observed was not due to infection with MTLV. A mouse antibody production test showed that mice inoculated with naive D10.G4.1 cells and their contact sentinels tested positive for MTLV using cell-line generated antigen, but tested negative in assays using MTLV antigen produced in mice. Metagenomic analysis was subsequently used to identify MuAstV-2 in feces from 2 sentinel mice that had recently seroconverted to MTLV. Two closely related astrovirus sequences (99.6% capsid identity) were obtained and shared 95% capsid amino acid identity with the MuAstV-2 virus sequenced from the D10.G4.1 cell line. These viruses are highly divergent from previously identified murine astroviruses, displaying <30% capsid identity, yet were closely related to murine astrovirus 2 (85% capsid identity), which had recently been isolated from feral mice in New York City. A MuAstV-2 specific PCR assay was developed and used to eradicate MuAstV-2 from the infected colony using a test and cull strategy. The newly identified MuAstV2 readily transmits to immunocompetent mouse strains by fecal-oral exposure, but fails to infect NOD-Prkdc(em26Cd52)Il2rg(em26Cd22)/NjuCrl (NCG) mice, which have significantly impaired adaptive and innate immune systems. Neither immunocompetent nor immunodeficient mice showed any astrovirus-associated pathology. MuAstV-2 may provide a valuable model for the study of specific aspects of astrovirus pathogenesis and virus-host interactions.

Aim:Heroin addiction is a chronic, relapsing disease that has genetic and environmental, including drug-induced, contributions. Stress influences the development of addictions. This study was conducted to determine if variants in stress-related genes are associated with opioid dependence (OD).Patients & methods:One hundred and twenty variants in 26 genes were analyzed in 597 Dutch subjects. Patients included 281 OD in methadone maintenance with or without heroin-assisted treatment and 316 controls.Results:Twelve SNPs in seven genes showed a nominally significant association with OD. Experiment-wise significant associations (p < 0.05) were found for three SNP pairs, through an interaction effect:NPY1R/GALrs4691910/rs1893679,NPY1R/GALrs4691910/rs3136541 andGALR1/GALrs9807208/rs3136541.Conclusion:This study lends more evidence to previous reports of association of stress-related variants with heroin dependence.

The development of the most successful cancer immunotherapies in solid tumors, immune-checkpoint blockade, has focused on factors regulating T-cell activation. Until recently, the field has maintained a predominately T-cell centric view of immunotherapy, leaving aside the impact of innate immunity and especially myeloid cells. Dendritic cells (DC) are dominant partners of T cells, necessary for initiation of adaptive immune responses. Emerging evidence supports a broader role for DCs in tumors including the maintenance and support of effector functions during T-cell responses. This relationship is evidenced by the association of activated DCs with immune-checkpoint blockade responses and transcriptional analysis of responding tumors demonstrating the presence of type I IFN transcripts and DC relevant chemokines. T-cell-inflamed tumors preferentially respond to immunotherapies compared with non-T-cell-inflamed tumors and this model suggests a potentially modifiable spectrum of tumor microenvironmental immunity. Although host and commensal factors may limit the T-cell-inflamed phenotype, tumor cell intrinsic factors are gaining prominence as therapeutic targets. For example, tumor WNT/beta-catenin signaling inhibits production of chemokine gradients and blocking DC recruitment to tumors. Conversely, mechanisms of innate immune nucleic acid sensing, normally operative during pathogen response, may enhance DC accumulation and make tumors more susceptible to cancer immunotherapy. Elucidating mechanisms whereby DCs infiltrate and become activated within tumors may provide new opportunities for therapeutic intervention. Conceptually, this would facilitate conversion of non-T-cellinflamed to T-cell-inflamed states or overcome secondary resistance mechanisms in T-cell-inflamed tumors, expanding the proportion of patients who benefit from cancer immunotherapy.

Piloerection (goosebumps) requires concerted actions of the hair follicle, the arrector pili muscle (APM), and the sympathetic nerve, providing a model to study interactions across epithelium, mesenchyme, and nerves. Here, we show that APMs and sympathetic nerves form a dual-component niche to modulate hair follicle stem cell (HFSC) activity. Sympathetic nerves form synapse-like structures with HFSCs and regulate HFSCs through norepinephrine, whereas APMs maintain sympathetic innervation to HFSCs. Without norepinephrine signaling, HFSCs enter deep quiescence by down-regulating the cell cycle and metabolism while up-regulating quiescence regulators Foxp1 and Fgf18. During development, HFSC progeny secretes Sonic Hedgehog (SHH) to direct the formation of this APM-sympathetic nerve niche, which in turn controls hair follicle regeneration in adults. Our results reveal a reciprocal interdependence between a regenerative tissue and its niche at different stages and demonstrate sympathetic nerves can modulate stem cells through synapse-like connections and neurotransmitters to couple tissue production with demands.