SummaryGene-environment interactions are determining factors for the etiology of psychiatric disorders, diabetes and cancer, and are thought to contribute to disease inheritance across generations. Small non-coding RNAs (sncRNAs) are potential vectors at the interface between genes and environment. Here, we report that environmental conditions involving traumatic stress in early life in mice altered microRNAs (miRNAs) expression, and behavioral and metabolic responses in the progeny. Several miRNAs were affected in the serum and brain of both, the traumatized animals and their progeny when adult, but also in the sperm of traumatized males. Injection of sperm RNAs from these males into fertilized wild-type oocytes reproduced the behavioral and metabolic alterations in the resulting offspring. These results strongly suggest that sncRNAs are sensitive to environmental factors in early life, and contribute to the inheritance of trauma-induced phenotypes across generations. They may offer potential diagnostic markers for associated pathologies in humans.While the genetic make-up of an individual contributes to disease risk and heritability 1 , environmental factors, in particular, adverse and traumatic experiences in early life are also critical. How they mediate their influence is poorly understood but likely involves nongenetic mechanisms. Small non-coding RNAs (sncRNAs) are potential mediators of geneenvironment interactions that can relay signals from the environment to the genome and exert regulatory functions on gene activity 2 . They are implicated in gene dysregulation in many diseases including psychiatric and neurological conditions, cancer and metabolic disorders 2-4 . Recent studies in C. elegans 5,6 and mice 7,8 have suggested that sncRNAs can * Corresponding author: mansuy@hifo.uzh.ch. $ Current address: Neuroscience Center, University Geneva, Switzerland Authors' contribution K.G. did all RT-qPCRs, behavioral tests, metabolic measurements, sperm RNA preparation for sequencing libraries and for RNA injection into fertilized oocytes and part of the sequencing analyses. A.J. performed Western blots and cell culture experiments and assisted with metabolic measurements. J.B. carried out the MSUS procedures and produced MSUS animals. J.P. and P.S. did most RNA sequencing analyses. P.P. did the RNA injection experiments. E.M. and L.F. helped design RNA sequencing analysis. K.G. and I.M.M. designed the study, interpreted the results and wrote the manuscript.

SUMMARY Colony stimulating factor-1 (Csf-1) receptor and its ligand Csf-1 control macrophage development, maintenance, and function. The development of both Langerhans cells (LCs) and microglia is highly dependent on Csf-1 receptor signaling but independent of Csf-1. Here we show that in both mice and humans, interleukin-34 (IL-34), an alternative ligand for Csf-1 receptor, is produced by keratinocytes in the epidermis and by neurons in the brain. Mice lacking IL-34 displayed a marked reduction of LCs and a decrease of microglia, whereas monocytes, dermal, and lymphoid tissue macrophages and DCs were unaffected. We identified IL-34 as a nonredundant cytokine for the development of LCs during embryo-genesis as well as for their homeostasis in the adult skin. Whereas inflammation-induced repopulation of LCs appears to be dependent on Csf-1, once inflammation is resolved, LC survival is again IL-34-dependent. In contrast, microglia and their yolk sac precursors develop independently of IL-34 but rely on it for their maintenance in the adult brain.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) has emerged as a crucial cytokine produced by auto-reactive T helper (Th) cells that initiate tissue inflammation. Multiple cell types can sense GM-CSF, but the identity of the pathogenic GM-CSF-responsive cells is unclear. By using conditional gene targeting, we systematically deleted the GM-CSF receptor (Csf2rb) in specific subpopulations throughout the myeloid lineages. Experimental autoimmune encephalomyelitis (EAE) progressed normally when either classical dendritic cells (cDCs) or neutrophils lacked GM-CSF responsiveness. The development of tissue-invading monocyte-derived dendritic cells (moDCs) was also unperturbed upon Csf2rb deletion. Instead, deletion of Csf2rb in CCR2(+)Ly6C(hi) monocytes phenocopied the EAE resistance seen in complete Csf2rb-deficient mice. High-dimensional analysis of tissue-infiltrating moDCs revealed that GM-CSF initiates a combination of inflammatory mechanisms. These results indicate that GM-CSF signaling controls a pathogenic expression signature in CCR2(+)Ly6C(hi) monocytes and their progeny, which was essential for tissue damage.

A nonviral vector for highly efficient site-specific integration would be desirable for many applications in transgenesis, including gene therapy. In this study we directly compared the genomic integration efficiencies of piggyBac, hyperactive Sleeping Beauty (SB11), Tol2, and Mos1 in four mammalian cell lines. piggyBac demonstrated significantly higher transposition activity in all cell lines whereas Mos1 had no activity. Furthermore, piggyBac transposase coupled to the GAL4 DNA-binding domain retains transposition activity whereas similarly manipulated gene products of Tol2 and SB11 were inactive. The high transposition activity of piggyBac and the flexibility for molecular modification of its transposase suggest the possibility of using it routinely for mammalian transgenesis.gene therapy ͉ site-specific ͉ transposase ͉ cancer ͉ mutagenesis

Pyroptosis is a form of lytic inflammatory cell death driven by inflammatory caspase-1, caspase-4, caspase-5 and caspase-11. These caspases cleave and activate the pore-forming protein gasdermin D (GSDMD) to induce membrane damage. By contrast, apoptosis is driven by apoptotic caspase-8 or caspase-9 and has traditionally been classified as an immunologically silent form of cell death. Emerging evidence suggests that therapeutics designed for cancer chemotherapy or inflammatory disorders such as SMAC mimetics, TAK1 inhibitors and BH3 mimetics promote caspase-8 or caspase-9-dependent inflammatory cell death and NLRP3 inflammasome activation. However, the mechanism by which caspase-8 or caspase-9 triggers cell lysis and NLRP3 activation is still undefined. Here, we demonstrate that during extrinsic apoptosis, caspase-1 and caspase-8 cleave GSDMD to promote lytic cell death. By engineering a novel Gsdmd D88A knock-in mouse, we further demonstrate that this proinflammatory function of caspase-8 is counteracted by caspase-3-dependent cleavage and inactivation of GSDMD at aspartate 88, and is essential to suppress GSDMD-dependent cell lysis during caspase-8-dependent apoptosis. Lastly, we provide evidence that channel-forming glycoprotein pannexin-1, but not GSDMD or GSDME promotes NLRP3 inflammasome activation during caspase-8 or caspase-9-dependent apoptosis.