Carossino, M;Kenney, D;O'Connell, AK;Montanaro, P;Tseng, AE;Gertje, HP;Grosz, KA;Ericsson, M;Huber, BR;Kurnick, SA;Subramaniam, S;Kirkland, TA;Walker, JR;Francis, KP;Klose, AD;Paragas, N;Bosmann, M;Saeed, M;Balasuriya, UBR;Douam, F;Crossland, NA;
PMID: 35336942 | DOI: 10.3390/v14030535
Animal models recapitulating COVID-19 are critical to enhance our understanding of SARS-CoV-2 pathogenesis. Intranasally inoculated transgenic mice expressing human angiotensin-converting enzyme 2 under the cytokeratin 18 promoter (K18-hACE2) represent a lethal model of SARS-CoV-2 infection. We evaluated the clinical and virological dynamics of SARS-CoV-2 using two intranasal doses (104 and 106 PFUs), with a detailed spatiotemporal pathologic analysis of the 106 dose cohort. Despite generally mild-to-moderate pneumonia, clinical decline resulting in euthanasia or death was commonly associated with hypothermia and viral neurodissemination independent of inoculation dose. Neuroinvasion was first observed at 4 days post-infection, initially restricted to the olfactory bulb suggesting axonal transport via the olfactory neuroepithelium as the earliest portal of entry. Absence of viremia suggests neuroinvasion occurs independently of transport across the blood-brain barrier. SARS-CoV-2 tropism was neither restricted to ACE2-expressing cells (e.g., AT1 pneumocytes), nor inclusive of some ACE2-positive cell lineages (e.g., bronchiolar epithelium and brain vasculature). Absence of detectable ACE2 protein expression in neurons but overexpression in neuroepithelium suggest this as the most likely portal of neuroinvasion, with subsequent ACE2 independent lethal neurodissemination. A paucity of epidemiological data and contradicting evidence for neuroinvasion and neurodissemination in humans call into question the translational relevance of this model.
Proc Natl Acad Sci U S A.
Xin Y, Kim J, Ni M, Wei Y, Okamoto H, Lee J, Adler C, Cavino K, Murphy AJ, Yancopoulos GD, Lin HC, Gromada J.
PMID: 26951663 | DOI: -
This study provides an assessment of the Fluidigm C1 platform for RNA sequencing of single mouse pancreatic islet cells. The system combines microfluidic technology and nanoliter-scale reactions. We sequenced 622 cells, allowing identification of 341 islet cells with high-quality gene expression profiles. The cells clustered into populations of α-cells (5%), β-cells (92%), δ-cells (1%), and pancreatic polypeptide cells (2%). We identified cell-type-specific transcription factors and pathways primarily involved in nutrient sensing and oxidation and cell signaling. Unexpectedly, 281 cells had to be removed from the analysis due to low viability, low sequencing quality, or contamination resulting in the detection of more than one islet hormone. Collectively, we provide a resource for identification of high-quality gene expression datasets to help expand insights into genes and pathways characterizing islet cell types. We reveal limitations in the C1 Fluidigm cell capture process resulting in contaminated cells with altered gene expression patterns. This calls for caution when interpreting single-cell transcriptomics data using the C1 Fluidigm system.
Löhr H, Hess S, Pereira MMA, Reinoß P, Leibold S, Schenkel C, Wunderlich CM, Kloppenburg P, Brüning JC, Hammerschmidt M.
PMID: - | DOI: 10.1016/j.celrep.2018.04.018
Anorexigenic pro-opiomelanocortin (Pomc)/alpha-melanocyte stimulating hormone (αMSH) neurons of the hypothalamic melanocortin system function as key regulators of energy homeostasis, also controlling somatic growth across different species. However, the mechanisms of melanocortin-dependent growth control still remain ill-defined. Here, we reveal a thus-far-unrecognized structural and functional connection between Pomc neurons and the somatotropic hypothalamo-pituitary axis. Excessive feeding of larval zebrafish causes leptin resistance and reduced levels of the hypothalamic satiety mediator pomca. In turn, this leads to reduced activation of hypophysiotropic somatostatin (Sst)-neurons that express the melanocortin receptor Mc4r, elevated growth hormone (GH) expression in the pituitary, and enhanced somatic growth. Mc4r expression and αMSH responsiveness are conserved in Sst-expressing hypothalamic neurons of mice. Thus, acquired leptin resistance and attenuation of pomca transcription in response to excessive caloric intake may represent an ancient mechanism to promote somatic growth when food resources are plentiful.
Wallace ML, Huang KW, Hochbaum D, Hyun M, Radeljic G, Sabatini BL
PMID: 32043968 | DOI: 10.7554/eLife.51271
The lateral habenula (LHb) is an epithalamic brain structure critical for processing and adapting to negative action outcomes. However, despite the importance of LHb to behavior and the clear anatomical and molecular diversity of LHb neurons, the neuron types of the habenula remain unknown. Here, we use high-throughput single-cell transcriptional profiling, monosynaptic retrograde tracing, and multiplexed FISH to characterize the cells of the mouse habenula. We find five subtypes of neurons in the medial habenula (MHb) that are organized into anatomical subregions. In the LHb, we describe four neuronal subtypes and show that they differentially target dopaminergic and GABAergic cells in the ventral tegmental area (VTA). These data provide a valuable resource for future study of habenular function and dysfunction and demonstrate neuronal subtype specificity in the LHb-VTA circuit
International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases
Märkl, B;Dintner, S;Schaller, T;Sipos, E;Kling, E;Miller, S;Farfan, F;Grochowski, P;Reitsam, N;Waidhauser, J;Hirschbühl, K;Spring, O;Fuchs, A;Wibmer, T;Boor, P;Beer, M;Wylezich, C;
PMID: 36584746 | DOI: 10.1016/j.ijid.2022.12.029
Omicron lineages BA.1/2 are considered to cause mild clinical courses. Nevertheless, fatal cases after those infections are recognized but little is known about risk factors.Twenty-three full and three partial autopsies in deceased with known Omicron BA.1/2 infections have been consecutively performed. The investigations included histology, blood analyses and molecular virus detection.COVID-19-associated diffuse alveolar damage (DAD) was found in only eight cases (31%). This rate is significantly lower compared to previous studies, including non-Omicron variants, where rates between 69% and 92% were observed. Neither vaccination nor known risk factors were significantly associated with a direct cause of death by COVID-19. Only those patients who were admitted to the clinic due to COVID-19 but not for other reasons had a significant association with a direct COVID-19 caused death (P > 0.001).).DAD still occurred in the Omicron BA.1/BA.2 era but at considerably lower frequency than seen with previous variants of concern. None of the known risk factors discriminated the cases with COVID-19-caused death from those that died due to a different disease. Therefore, the host's genomics might play a key role in this regard. Further studies should elucidate the existence of such a genomic risk factor.
O'Leary, TP;Kendrick, RM;Bristow, BN;Sullivan, KE;Wang, L;Clements, J;Lemire, AL;Cembrowski, MS;
PMID: 36425768 | DOI: 10.1016/j.isci.2022.105497
The central amygdala (CEA) has been richly studied for interpreting function and behavior according to specific cell types and circuits. Such work has typically defined molecular cell types by classical inhibitory marker genes; consequently, whether marker-gene-defined cell types exhaustively cover the CEA and co-vary with connectivity remains unresolved. Here, we combined single-cell RNA sequencing, multiplexed fluorescent in situ hybridization, immunohistochemistry, and long-range projection mapping to derive a "bottom-up" understanding of CEA cell types. In doing so, we identify two major cell types, encompassing one-third of all CEA neurons, that have gone unresolved in previous studies. In spatially mapping these novel types, we identify a non-canonical CEA subdomain associated with Nr2f2 expression and uncover an Isl1-expressing medial cell type that accounts for many long-range CEA projections. Our results reveal new CEA organizational principles across cell types and spatial scales and provide a framework for future work examining cell-type-specific behavior and function.
Steuernagel, L;Lam, BYH;Klemm, P;Dowsett, GKC;Bauder, CA;Tadross, JA;Hitschfeld, TS;Del Rio Martin, A;Chen, W;de Solis, AJ;Fenselau, H;Davidsen, P;Cimino, I;Kohnke, SN;Rimmington, D;Coll, AP;Beyer, A;Yeo, GSH;Brüning, JC;
PMID: 36266547 | DOI: 10.1038/s42255-022-00657-y
The hypothalamus plays a key role in coordinating fundamental body functions. Despite recent progress in single-cell technologies, a unified catalog and molecular characterization of the heterogeneous cell types and, specifically, neuronal subtypes in this brain region are still lacking. Here, we present an integrated reference atlas, 'HypoMap,' of the murine hypothalamus, consisting of 384,925 cells, with the ability to incorporate new additional experiments. We validate HypoMap by comparing data collected from Smart-Seq+Fluidigm C1 and bulk RNA sequencing of selected neuronal cell types with different degrees of cellular heterogeneity. Finally, via HypoMap, we identify classes of neurons expressing glucagon-like peptide-1 receptor (Glp1r) and prepronociceptin (Pnoc), and validate them using single-molecule in situ hybridization. Collectively, HypoMap provides a unified framework for the systematic functional annotation of murine hypothalamic cell types, and it can serve as an important platform to unravel the functional organization of hypothalamic neurocircuits and to identify druggable targets for treating metabolic disorders.
Biering, SB;Sarnik, SA;Wang, E;Zengel, JR;Leist, SR;Schäfer, A;Sathyan, V;Hawkins, P;Okuda, K;Tau, C;Jangid, AR;Duffy, CV;Wei, J;Gilmore, RC;Alfajaro, MM;Strine, MS;Nguyenla, X;Van Dis, E;Catamura, C;Yamashiro, LH;Belk, JA;Begeman, A;Stark, JC;Shon, DJ;Fox, DM;Ezzatpour, S;Huang, E;Olegario, N;Rustagi, A;Volmer, AS;Livraghi-Butrico, A;Wehri, E;Behringer, RR;Cheon, DJ;Schaletzky, J;Aguilar, HC;Puschnik, AS;Button, B;Pinsky, BA;Blish, CA;Baric, RS;O'Neal, WK;Bertozzi, CR;Wilen, CB;Boucher, RC;Carette, JE;Stanley, SA;Harris, E;Konermann, S;Hsu, PD;
PMID: 35879412 | DOI: 10.1038/s41588-022-01131-x
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes a range of symptoms in infected individuals, from mild respiratory illness to acute respiratory distress syndrome. A systematic understanding of host factors influencing viral infection is critical to elucidate SARS-CoV-2-host interactions and the progression of Coronavirus disease 2019 (COVID-19). Here, we conducted genome-wide CRISPR knockout and activation screens in human lung epithelial cells with endogenous expression of the SARS-CoV-2 entry factors ACE2 and TMPRSS2. We uncovered proviral and antiviral factors across highly interconnected host pathways, including clathrin transport, inflammatory signaling, cell-cycle regulation, and transcriptional and epigenetic regulation. We further identified mucins, a family of high molecular weight glycoproteins, as a prominent viral restriction network that inhibits SARS-CoV-2 infection in vitro and in murine models. These mucins also inhibit infection of diverse respiratory viruses. This functional landscape of SARS-CoV-2 host factors provides a physiologically relevant starting point for new host-directed therapeutics and highlights airway mucins as a host defense mechanism.
Findlay-Wilson, S;Easterbrook, L;Smith, S;Pope, N;Humphries, G;Schuhmann, H;Ngabo, D;Rayner, E;Otter, AD;Coleman, T;Hicks, B;Graham, VA;Halkerston, R;Apostolakis, K;Taylor, S;Fotheringham, S;Horton, A;Tree, JA;Wand, M;Hewson, R;Dowall, SD;
PMID: 35533779 | DOI: 10.1016/j.antiviral.2022.105332
Antibodies against SARS-CoV-2 are important to generate protective immunity, with convalescent plasma one of the first therapies approved. An alternative source of polyclonal antibodies suitable for upscaling would be more amendable to regulatory approval and widespread use. In this study, sheep were immunised with SARS-CoV-2 whole spike protein or one of the subunit proteins: S1 and S2. Once substantial antibody titres were generated, plasma was collected and samples pooled for each antigen. Non-specific antibodies were removed via affinity-purification to yield candidate products for testing in a hamster model of SARS-CoV-2 infection. Affinity-purified polyclonal antibodies to whole spike, S1 and S2 proteins were evaluated for in vitro for neutralising activity against SARS-CoV-2 Wuhan-like virus (Australia/VIC01/2020) and a recent variant of concern, B.1.1.529 BA.1 (Omicron), antibody-binding, complement fixation and phagocytosis assays were also performed. All antibody preparations demonstrated an effect against SARS-CoV-2 disease in the hamster model of challenge, with those raised against the S2 subunit providing the most promise. A rapid, cost-effective therapy for COVID-19 was developed which provides a source of highly active immunoglobulin specific to SARS-CoV-2 with multi-functional activity.Crown
Lyra E Silva, NM;Barros-Aragão, FGQ;De Felice, FG;Ferreira, ST;
PMID: 35257690 | DOI: 10.1016/j.neuropharm.2022.109023
Acute neurological alterations have been associated with SARS-CoV-2 infection. Additionally, it is becoming clear that coronavirus disease 2019 (COVID-19) survivors may experience long-term neurological abnormalities, including cognitive deficits and mood alterations. The mechanisms underlying acute and long-term impacts of COVID-19 in the brain are being actively investigated. Due to the heterogeneous manifestations of neurological outcomes, it is possible that different mechanisms operate following SARS-CoV-2 infection, which may include direct brain infection by SARS-CoV-2, mechanisms resulting from hyperinflammatory systemic disease, or a combination of both. Inflammation is a core feature of COVID-19, and both central and systemic inflammation are known to lead to acute and persistent neurological alterations in other diseases. Here, we review evidence indicating that COVID-19 is associated with neuroinflammation, along with blood-brain barrier dysfunction. Similar neuroinflammatory signatures have been associated with Alzheimer's disease and major depressive disorder. Current evidence demonstrates that patients with pre-existing cognitive and neuropsychiatric deficits show worse outcomes upon infection by SARS-CoV-2 and, conversely, COVID-19 survivors may be at increased risk of developing dementia and mood disorders. Considering the high prevalence of COVID-19 patients that recovered from infection in the world and the alarming projections for the prevalence of dementia and depression, investigation of possible molecular similarities between those diseases may shed light on mechanisms leading to long-term neurological abnormalities in COVID-19 survivors.
Smith, KD;Prince, DK;Henriksen, K;Nicosia, RF;Alpers, CE;Akilesh, S;
PMID: 35227689 | DOI: 10.1016/j.kint.2022.01.033
Collapsing glomerulopathy is a histologically distinct variant of focal and segmental glomerulosclerosis that presents with heavy proteinuria and portends a poor prognosis. Collapsing glomerulopathy can be triggered by viral infections such as HIV or SARS-CoV-2. Transcriptional profiling of collapsing glomerulopathy lesions is difficult since only a few glomeruli may exhibit this histology within a kidney biopsy and the mechanisms driving this heterogeneity are unknown. Therefore, we used recently developed digital spatial profiling (DSP) technology which permits quantification of mRNA at the level of individual glomeruli. Using DSP, we profiled 1,852 transcripts in glomeruli isolated from formalin fixed paraffin embedded sections from HIV or SARS-CoV-2 infected patients with biopsy-confirmed collapsing glomerulopathy and used normal biopsy sections as controls. Even though glomeruli with collapsing features appeared histologically similar across both groups of patients by light microscopyhe increased resolution of DSP uncovered intra- and inter-patient heterogeneity in glomerular transcriptional profiles that were missed in early laser capture microdissection studies of pooled glomeruli. Focused validation using immunohistochemistry and RNA in situ hybridization showed good concordance with DSP results. Thus, DSP represents a powerful method to dissect transcriptional programs of pathologically discernible kidney lesions.
Klein, R;Soung, A;Sissoko, C;Nordvig, A;Canoll, P;Mariani, M;Jiang, X;Bricker, T;Goldman, J;Rosoklija, G;Arango, V;Underwood, M;Mann, JJ;Boon, A;Dowrk, A;Boldrini, M;
PMID: 34729556 | DOI: 10.21203/rs.3.rs-1031824/v1
Infection with the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is associated with onset of neurological and psychiatric symptoms during and after the acute phase of illness 1-4 . Acute SARS-CoV-2 disease (COVID-19) presents with deficits of memory, attention, movement coordination, and mood. The mechanisms of these central nervous system symptoms remain largely unknown.In an established hamster model of intranasal infection with SARS-CoV-2 5 , and patients deceased from COVID-19, we report a lack of viral neuroinvasion despite aberrant BBB permeability, microglial activation, and brain expression of interleukin (IL)-1β and IL-6, especially within the hippocampus and the inferior olivary nucleus of the medulla, when compared with non-COVID control hamsters and humans who died from other infections, cardiovascular disease, uremia or trauma. In the hippocampus dentate gyrus of both COVID-19 hamsters and humans, fewer cells expressed doublecortin, a marker of neuroblasts and immature neurons.Despite absence of viral neurotropism, we find SARS-CoV-2-induced inflammation, and hypoxia in humans, affect brain regions essential for fine motor function, learning, memory, and emotional responses, and result in loss of adult hippocampal neurogenesis. Neuroinflammation could affect cognition and behaviour via disruption of brain vasculature integrity, neurotransmission, and neurogenesis, acute effects that may persist in COVID-19 survivors with long-COVID symptoms.
