The rockefeller university

Baksh et al. show that oncogenic epidermal stem cells require extracellular serine to initiate squamous cell carcinoma via altering dioxygenases that remove H3K27me3. Tissue stem cells are the cell of origin for many malignancies. Metabolites regulate the balance between self-renewal and differentiation, but whether endogenous metabolic pathways or nutrient availability predispose stem cells towards transformation remains unknown. Here, we address this question in epidermal stem cells (EpdSCs), which are a cell of origin for squamous cell carcinoma. We find that oncogenic EpdSCs are serine auxotrophs whose growth and self-renewal require abundant exogenous serine. When extracellular serine is limited, EpdSCs activate de novo serine synthesis, which in turn stimulates alpha-ketoglutarate-dependent dioxygenases that remove the repressive histone modification H3K27me3 and activate differentiation programmes. Accordingly, serine starvation or enforced alpha-ketoglutarate production antagonizes squamous cell carcinoma growth. Conversely, blocking serine synthesis or repressing alpha-ketoglutarate-driven demethylation facilitates malignant progression. Together, these findings reveal that extracellular serine is a critical determinant of EpdSC fate and provide insight into how nutrient availability is integrated with stem cell fate decisions during tumour initiation.

Mammalian cells contain two isoforms of RNA polymerase III (Pol III) that differ in only a single subunit, with POLR3G in one form (Pol III alpha) and the related POLR3GL in the other form (Pol III beta). Previous research indicates that POLR3G and POLR3GL are differentially expressed, with POLR3G expression being highly enriched in embryonic stem cells (ESCs) and tumor cells relative to the ubiquitously expressed POLR3GL. To date, the functional differences between these two subunits remain largely unexplored, especially in vivo. Here, we show that POLR3G and POLR3GL containing Pol III complexes bind the same target genes and assume the same functions both in vitro and in vivo and, to a significant degree, can compensate for each other in vivo. Notably, an observed defect in the differentiation ability of POLR3G knockout ESCs can be rescued by exogenous expression of POLR3GL. Moreover, whereas POLR3G knockout mice die at a very early embryonic stage, POLR3GL knockout mice complete embryonic development without noticeable defects but die at about 3 wk after birth with signs of both general growth defects and potential cerebellum-related neuronal defects. The different phenotypes of the knockout mice likely reflect differential expression levels of POLR3G and POLR3GL across developmental stages and between tissues and insufficient amounts of total Pol III in vivo.

Bats possess extraordinary adaptations, including flight, echolocation, extreme longevity and unique immunity. High-quality genomes are crucial for understanding the molecular basis and evolution of these traits. Here we incorporated long-read sequencing and state-of-the-art scaffolding protocols(1)to generate, to our knowledge, the first reference-quality genomes of six bat species (Rhinolophus ferrumequinum,Rousettus aegyptiacus,Phyllostomus discolor,Myotis myotis,Pipistrellus kuhliiandMolossus molossus). We integrated gene projections from our 'Tool to infer Orthologs from Genome Alignments' (TOGA) software with de novo and homology gene predictions as well as short- and long-read transcriptomics to generate highly complete gene annotations. To resolve the phylogenetic position of bats within Laurasiatheria, we applied several phylogenetic methods to comprehensive sets of orthologous protein-coding and noncoding regions of the genome, and identified a basal origin for bats within Scrotifera. Our genome-wide screens revealed positive selection on hearing-related genes in the ancestral branch of bats, which is indicative of laryngeal echolocation being an ancestral trait in this clade. We found selection and loss of immunity-related genes (including pro-inflammatory NF-kappa B regulators) and expansions of anti-viral APOBEC3 genes, which highlights molecular mechanisms that may contribute to the exceptional immunity of bats. Genomic integrations of diverse viruses provide a genomic record of historical tolerance to viral infection in bats. Finally, we found and experimentally validated bat-specific variation in microRNAs, which may regulate bat-specific gene-expression programs. Our reference-quality bat genomes provide the resources required to uncover and validate the genomic basis of adaptations of bats, and stimulate new avenues of research that are directly relevant to human health and disease(1). Reference-quality genomes for six bat species shed light on the phylogenetic position of Chiroptera, and provide insight into the genetic underpinnings of the unique adaptations of this clade.

Selective serotonin reuptake inhibitors (SSRIs) are the most widely prescribed drugs for mood disorders. While the mechanism of SSRI action is still unknown, SSRIs are thought to exert therapeutic effects by elevating extracellular serotonin levels in the brain, and remodel the structural and functional alterations dysregulated during depression. To determine their precise mode of action, we tested whether such neuroadaptive processes are modulated by regulation of specific gene expression programs. Here we identify a transcriptional program regulated by activator protein-1 (AP-1) complex, formed by c-Fos and c-Jun that is selectively activated prior to the onset of the chronic SSRI response. The AP-1 transcriptional program modulates the expression of key neuronal remodeling genes, including S100a10 (p11), linking neuronal plasticity to the antidepressant response. We find that AP-1 function is required for the antidepressant effect in vivo. Furthermore, we demonstrate how neurochemical pathways of BDNF and FGF2, through the MAPK, PI3K, and JNK cascades, regulate AP-1 function to mediate the beneficial effects of the antidepressant response. Here we put forth a sequential molecular network to track the antidepressant response and provide a new avenue that could be used to accelerate or potentiate antidepressant responses by triggering neuroplasticity.

Growth factor deficiency in adulthood constitutes a distinct clinical syndrome with significant morbidities including abnormal body composition, reduced energy, affective disturbances, dyslipidemia, and increased cardiovascular risk. Protein replacement therapies using recombinant proteins or enzymes represent the only approved treatment. Combinatorial antibodies have shown great promise as a new class of therapeutic molecules because they act as "mechanism-based antibodies" with both agonist and antagonist activities. Using leptin, a key hormone in energy metabolism, as an example, a function-guided approach is developed to select combinatorial antibodies with high potency and full agonist activity that substitute natural growth factors in vivo. The identified antibody shows identical biochemical properties and cellular profiles as leptin, and rescues leptin-deficiency in ob/ob mice. Remarkably, the antibody activates leptin receptors that are otherwise nonfunctional because of mutations (L372A and A409E). Combinatorial antibodies have significant advantages over recombinant proteins for chronical usage in terms of immunological tolerance and biological stability.

Background Clinical and animal studies show that alcohol consumption during pregnancy produces lasting behavioral disturbances in offspring, including increased alcohol drinking, which are linked to inflammation in the brain and disturbances in neurochemical systems that promote these behaviors. These include the neuropeptide, melanin-concentrating hormone (MCH), which is mostly expressed in the lateral hypothalamus (LH). Maternal ethanol administration at low-to-moderate doses, while stimulating MCH neurons without affecting apoptosis or gliogenesis, increases in LH the density of neurons expressing the inflammatory chemokine C-C motif ligand 2 (CCL2) and its receptor CCR2 and their colocalization with MCH. These neural effects associated with behavioral changes are reproduced by maternal CCL2 administration, reversed by a CCR2 antagonist, and consistently stronger in females than males. The present study investigates in the embryo the developmental origins of this CCL2/CCR2-mediated stimulatory effect of maternal ethanol exposure on MCH neurons. Methods Pregnant rats from embryonic day 10 (E10) to E15 during peak neurogenesis were orally administered ethanol at a moderate dose (2 g/kg/day) or peripherally injected with CCL2 or CCR2 antagonist to test this neuroimmune system's role in ethanol's actions. Using real-time quantitative PCR, immunofluorescence histochemistry, in situ hybridization, and confocal microscopy, we examined in embryos at E19 the CCL2/CCR2 system and MCH neurons in relation to radial glia progenitor cells in the hypothalamic neuroepithelium where neurons are born and radial glia processes projecting laterally through the medial hypothalamus that provide scaffolds for neuronal migration into LH. Results We demonstrate that maternal ethanol increases radial glia cell density and their processes while stimulating the CCL2/CCR2 system and these effects are mimicked by maternal administration of CCL2 and blocked by a CCR2 antagonist. While stimulating CCL2 colocalization with radial glia and neurons but not microglia, ethanol increases MCH neuronal number near radial glia cells and making contact along their processes projecting into LH. Further tests identify the CCL2/CCR2 system in NEP as a primary source of ethanol's sexually dimorphic actions. Conclusions These findings provide new evidence for how an inflammatory chemokine pathway functions within neuroprogenitor cells to mediate ethanol's long-lasting, stimulatory effects on peptide neurons linked to adolescent drinking behavior.

Based on national registry reports, after age 42, the number of IVF cycles utilizing autologous oocytes is very small; after age 43, autologous oocyte use in US IVF cycles is almost non-existent. We here argue that the in vitro fertilization (IVF) field has created a self-fulfilling prophecy by basically abandoning the utilization of autologous oocytes after ages 42-43 years. This not only resulted in almost no IVF cycles with autologous oocytes being performed but also in abandonment of research that could lead to improvements in IVF outcomes in older women when using autologous oocytes. As a consequence, IVF has largely stagnated in this area. We further argue that third-party oocyte donation in clinical IVF should be considered a treatment failure, as it requires patients to choose a second rather than a first-choice treatment. Such a redesignation of third-party egg donation would not only be appropriate but could lead to necessary changes in physician attitudes, considering that women almost exclusively prefer to conceive with their autologous oocytes.

Aims Investigating human heart development and applying this to deviations resulting in disease is incomplete without molecular characterization of the cell types required for normal functioning. We investigated foetal human heart single-cell transcriptomes from mid-gestational healthy and anti-SSA/Ro associated congenital heart block (CHB) samples. Methods and results Three healthy foetal human hearts (19th to 22nd week of gestation) and one foetal heart affected by autoimmune-associated CHB (21st week of gestation) were subjected to enzymatic dissociation using the Langendorff preparation to obtain single-cell suspensions followed by 10x Genomics- and Illumina-based single-cell RNA-sequencing (scRNA-seq). In addition to the myocytes, fibroblasts, immune cells, and other minor cell types, previously uncharacterized diverse sub-populations of endothelial cells were identified in the human heart. Differential gene expression analysis revealed increased and heterogeneous interferon responses in varied cell types of the CHB heart compared with the healthy controls. In addition, we also identified matrisome transcripts enriched in CHB stromal cells that potentially contribute to extracellular matrix deposition and subsequent fibrosis. Conclusion These data provide an information-rich resource to further our understanding of human heart development, which, as illustrated by comparison to a heart exposed to a maternal autoimmune environment, can be leveraged to provide insight into the pathogenesis of disease.

The CRISPR RNA (crRNA)-guided nuclease Cas13 recognizes complementary viral transcripts to trigger the degradation of both host and viral RNA during the type VI CRISPR-Cas antiviral response. However, how viruses can counteract this immunity is not known. We describe a listeriaphage (phi LS46) encoding an anti-CRISPR protein (AcrVIA1) that inactivates the type VI-A CRISPR system of Listeria seeligeri. Using genetics, biochemistry, and structural biology, we found that AcrVIA1 interacts with the guide-exposed face of Cas13a, preventing access to the target RNA and the conformational changes required for nuclease activation. Unlike inhibitors of DNA-cleaving Cas nucleases, which cause limited immunosuppression and require multiple infections to bypass CRISPR defenses, a single dose of AcrVIA1 delivered by an individual virion completely dismantles type VI-A CRISPR-mediated immunity.