Project description:We report that monocytes contribute to the maintenance of BAT macrophages in a dynamic manner at steady state, and allow tissue remodelling during BAT expansion. Using scRNA-Seq, we explored monocyte and macrophage diversity in BAT at steady state and during BAT expansion.
Project description:Obesity is a polygenic disorder with variable penetrance in the general population. Brown adipose tissue (BAT) is a major regulator of energy expenditure and metabolic physiology due to a specialized proteome that orchestrates futile metabolic cycles, which could be leveraged to treat obesity. However, nearly all mechanistic studies of BAT protein function occur in a single inbred mouse strain, which has limited understanding of generalizable mechanisms of BAT regulation over metabolism. Here we perform deep quantitative multiplexed proteomics of BAT across a cohort of 163 genetically defined Diversity Outbred (DO) mice, a model that parallels the genetic and phenotypic variation found in the human population. Leveraging the high variation afforded by this model, we define the functional architecture of the outbred BAT proteome, comprising 10,479 proteins. In doing so, we assign novel co-operative functions to 2,578 proteins with 780 established protein networks. We demonstrate that this analytic framework enables systematic discovery of regulators of BAT function, exemplified by uncovering SFXN5 and LETMD1 as modulators of UCP1-dependent thermogenesis. We also identify 638 proteins that underlie protection from, or sensitivity to, at least one parameter of metabolic disease. From this basis, we identify the Na+/K+- ATPase α2 subunit as an inhibitor of BAT energy expenditure, that increases adiposity through antagonism of calcium influx-dependent activation of thermogenic effectors. We provide this Outbred Proteomic Architecture as a resource for understanding conserved mechanisms of BAT regulation over metabolic physiology.
Project description:Zoonotic influenza A viruses of avian origin can cause severe disease in individuals, or even global pandemics, and thus pose a threat to human populations. Waterfowl and shorebirds are believed to be the reservoir for all influenza A viruses, but this has recently been challenged by the identification of novel influenza A viruses in bats. The major bat influenza A virus envelope glycoprotein, haemagglutinin, does not bind the canonical influenza A virus receptor, sialic acid or any other glycan, despite its high sequence and structural homology with conventional haemagglutinins. This functionally uncharacterized plasticity of the bat influenza A virus haemagglutinin means the tropism and zoonotic potential of these viruses has not been fully determined. Here we show, using transcriptomic profiling of susceptible versus non-susceptible cells in combination with genome-wide CRISPR-Cas9 screening, that the major histocompatibility complex class II (MHC-II) human leukocyte antigen DR isotype (HLA-DR) is an essential entry determinant for bat influenza A viruses. Genetic ablation of the HLA-DR α-chain rendered cells resistant to infection by bat influenza A virus, whereas ectopic expression of the HLA-DR complex in non-susceptible cells conferred susceptibility. Expression of MHC-II from different bat species, pigs, mice or chickens also conferred susceptibility to infection. Notably, the infection of mice with bat influenza A virus resulted in robust virus replication in the upper respiratory tract, whereas mice deficient for MHC-II were resistant. Collectively, our data identify MHC-II as a crucial entry mediator for bat influenza A viruses in multiple species, which permits a broad vertebrate tropism.
Project description:Brown adipose tissue (BAT) was suggested to play an important role in lipid and glucose metabolism in rodents and possibly also in humans. In the current study, we used genetic and correlation analyses in the BXH/HXB recombinant inbred (RI) strains, derived from Brown Norway (BN) and spontaneously hypertensive rats (SHR), to identify genetic determinants of BAT function and its role in the pathogenesis of metabolic disturbances. Linkage analyses revealed significant quantitative trait locus (QTL) associated with interscapular BAT mass in the vicinity of the Cd36 (fatty acid translocase) gene on chromosome 4. Additional two closely linked QTL asociated with glucose oxidation and incorporation into BAT lipids were detected near the Wars2 (tryptophanyl tRNA synthetase 2, mitochondrial) candidate gene on chromosome 2.
Project description:The bat offers an alternative paradigm to the standard mouse and chick model of limb development as it has extremely divergent forelimbs (long digits supporting a wing) and hindlimbs (short digits and claws) due the distinct requirements of both aerial and terrestrial locomotion. We used a cross-species microarray approach to identify differentially expressed (DE) genes between the bat (Minniopterus natalensis) forelimb and hindlimb autopods at Carollia developmental stages (CS) 16 and CS17, and between the bat (CS17) and mouse (E13.5) forelimb autopods. Several DE genes were identified, including two homeobox genes, Meis2, a proximal limb-patterning gene, and Hoxd11, a gene involved in digit elongation. Both genes are significantly over-expressed in the developing bat forelimb as compared to the hindlimb and equivalently staged mouse forelimbs. A reference design was used in this microarray experiment. A pool of left and right mouse forelimb autopods from 24 embryos was used as the reference sample. This sample was directly compared to individual CS16 and CS17 bat fore- and hindlimbs (left and right of one individual pooled) that were classified as the test conditions. Four experimental sessions were performed using an independently amplified mouse reference pool and 4 biological repeats for the bat limbs. These samples were co-hybridised to OPERON Mouse OpArray (ver. 4.0) spotted oligonucleotide slides to perform a competitive Cross-Species Hybridisation experiment. The bat aRNA (test) samples were labelled with Cy3 dye (green signal), the mouse aRNA (reference) sample was labelled with Cy5 dye (red signal).
Project description:Bat adenoviruses are a group of recently identified adenoviruses (AdVs) which are highly prevalent in bats yet share low similarity to known AdVs from other species. In this study, deep RNA sequencing was used to analyze the transcriptome at five time points following the infection of a bat AdV in a kidney cell line derived from a myotis bat species. Evidence of AdV replication was observed with the proportion of viral RNAs ranging from 0.01% at 6 h to 1.3% at 18 h. Further analysis of viral temporal gene expression revealed three replication stages; the early stage genes encoding mainly for host interaction proteins, the intermediate stage genes for the DNA replication and assembly proteins, and the late stage genes for most structural proteins. Several bat AdV genes were expressed at stages that differed from their counterpart genes previously reported for human AdV. In addition, single-base resolution splice sites of several genes and promoter regions of all 30 viral genes were fully determined. Simultaneously, the temporal cellular gene expression profiles were identified. The most overrepresented functional categories of the differentially expressed genes were related to cellular immune response, transcription, translation, and DNA replication and repair. Taken together, the deep RNA sequencing provided a global, transcriptional profile of the novel BtAdV and the virus-host interactions, which will be useful for the understanding and investigation of AdV replication, pathogenesis and specific virus-bat interactions in future research. Deep RNA sequencing was used to analyze the transcriptome at five time points(0h,6h,8h, 12h 18h) following the infection of a bat AdV in a bat kidney cell.
Project description:Bats are a major reservoir of zoonotic viruses, and there has been growing interest in characterizing bat-specific features of innate immunity and inflammation. Recent studies have revealed bat-specific adaptations affecting interferon (IFN) signaling and IFN-stimulated genes (ISGs), but we still have a limited understanding of the genetic mechanisms that have shaped the evolution of bat immunity. Here we investigated the transcriptional and epigenetic dynamics of transposable elements (TEs) during the type I IFN response in little brown bat (Myotis lucifugus) primary embryonic fibroblast cells, using RNA-seq and CUT&RUN. We found multiple bat-specific TEs that undergo both locus-specific and family-level transcriptional upregulation in response to IFN. Our transcriptome reassembly identified multiple ISGs that have acquired novel exons from bat-specific TEs, including NRLC5, SLNF5 and a previously unannotated isoform of the IFITM2 gene. We also identified examples of TE-derived regulatory elements, but did not find strong evidence supporting genome-wide epigenetic activation of TEs in response to IFN. Collectively, our study uncovers numerous TE-derived transcripts, proteins, and alternative isoforms that are induced by IFN in Myotis lucifugus cells, highlighting potential candidate loci that contribute to bat-specific immune function.