Inhibition of SARS-CoV-2 infections in engineered human tissues using clinical-grade soluble human ACE2

We have previously provided the first genetic evidence that angiotensin converting enzyme 2 (ACE2) is the critical receptor for severe acute respiratory syndrome coronavirus (SARS-CoV), and ACE2 protects the lung from injury, providing a molecular explanation for the severe lung failure and death due to SARS-CoV infections. ACE2 has now also been identified as a key receptor for SARS-CoV-2 infections, and it has been proposed that inhibiting this interaction might be used in treating patients with COVID-19. However, it is not known whether human recombinant soluble ACE2 (hrsACE2) blocks growth of SARS-CoV-2. Here, we show that clinical grade hrsACE2 reduced SARS-CoV-2 recovery from Vero cells by a factor of 1,000-5,000. An equivalent mouse rsACE2 had no effect. We also show that SARS-CoV-2 can directly infect engineered human blood vessel organoids and human kidney organoids, which can be inhibited by hrsACE2. These data demonstrate that hrsACE2 can significantly block early stages of SARS-CoV-2 infections

ACE2 is the critical in vivo receptor for SARS-CoV-2 in a novel COVID-19 mouse model with TNF-and IFN?-driven immunopathology

Despite tremendous progress in the understanding of COVID-19, mechanistic insight into immunological, disease-driving factors remains limited. We generated maVie16, a mouse-adapted SARS-CoV-2, by serial passaging of a human isolate. In silico modeling revealed how only three Spike mutations of maVie16 enhanced interaction with murine ACE2. maVie16 induced profound pathology in BALB/c and C57BL/6 mice, and the resulting mouse COVID-19 (mCOVID-19) replicated critical aspects of human disease, including early lymphopenia, pulmonary immune cell infiltration, pneumonia, and specific adaptive immunity. Inhibition of the proinflammatory cyto-kines IFN? and TNF substantially reduced immunopathology. Importantly, genetic ACE2-deficiency completely prevented mCOVID-19 development. Finally, inhalation therapy with recombinant ACE2 fully protected mice from mCOVID-19, revealing a novel and efficient treatment. Thus, we here present maVie16 as a new tool to model COVID-19 for the discovery of new therapies and show that disease severity is determined by cytokine-driven immunopathology and critically dependent on ACE2 in vivo. © Gawish et al

Redundant and specific functions of histone deacetylases HDAC1 and HDAC2 in brain development

Die Steuerung der Proliferation und Differenzierung ist für alle Organismen essentiell, um ihre Integrität und ihr Überleben zu sichern. Während der Entwicklung eines vielzelligen Organismus müssen Zelltyp-spezifische Genexpressionsmuster etabliert und beibehalten werden. Chromatinmodifikationen wie die Histonacetylierung spielen eine entscheidende Rolle in der transkriptionellen Kontrolle und definieren somit die Entwicklung von Organen und Zelltypen. Um den Beitrag der beiden paralogen Histondeacetylasen HDAC1 und HDAC2 im Nervensystem zu untersuchen, deletierten wir verschiedene Kombinationen von Hdac1/2 Allelen der Maus mittels Nestin-Cre. Während individuelle HDAC1 oder HDAC2 Knock-outs zu keinem offensichtlichen Phänotyp führten, zeigten Doppel-Knock-out Mäuse veränderte Chromatin-strukturen, DNA-Schäden, Apoptose und embryonale Letalität. Expression einzelner Hdac1 oder Hdac2 Allele in Abwesenheit des jeweiligen Paralogs führte zu sehr unterschiedlichen Phänotypen, was auf spezifische HDAC1/2 Funktionen im Nervensystem hinweist. Überraschenderweise war ein einziges Hdac2 Allel für normale Entwicklung des Gehirns ausreichend, während Mäuse mit einem einzigen Hdac1 Allel beeinträchtigte Gehirnentwicklung und perinatale Letalität aufwiesen. Dieser Phänotyp erklärte sich durch reduzierte Proliferation und vorzeitige Differenzierung vermittelt durch Überexpression der Protein Kinase C-Delta. Zusammengefasst bedeutet dies, dass HDAC1 und HDAC2 eine gemeinsame Funktion bei der Aufrechterhaltung von intakten Chromatin-strukturen haben und dass HDAC2 eine einzigartige und wichtige Rolle in der Kontrolle der Differenzierung von neuronalen Vorläuferzellen hat. Zur weiteren Analyse der einzelnen Funktionen dieser beiden Enzyme in verschiedenen experimentellen Kontexten entwickelten wir neue Mausmodelle wie HDAC1/2-Biotin Knock-in Mäuse und Knock-in-Mäuse, die katalytisch inaktive HDAC1/2 Isoformen exprimieren. Gemeinsam erlauben diese Mäuse HDAC1/2 Interaktionspartner und assoziierte genomische Sequenzen sowie die Rolle der enzymatischen Aktivität im Vergleich zur strukturellen Funktion zu analysieren.The control of cellular proliferation and differentiation is essential for all organisms to ensure their integrity and survival. During the development of a multicellular organism cell fate decisions have to be taken and lineage-specific gene expression patterns have to be established and maintained. Chromatin modifications including histone acetylation play a crucial role in the control of transcriptional programs that define the development of organs and cell types starting from stem cells and progenitors. To examine the contribution of the two highly related histone deacetylases HDAC1 and HDAC2, we deleted different combinations of Hdac1 and Hdac2 alleles in mouse neural precursor cells by Nestin-Cre. Individual deletions of HDAC1 or HDAC2 did not result in obvious phenotypes, whereas double knock-out mice displayed disturbed chromatin structure, DNA damage, apoptosis and embryonic lethality. Expression of a single allele of Hdac1 or Hdac2 in the absence of the respective paralog led to highly diverse phenotypes, indicating non-redundant functions of the two deacetylases in the nervous system. Surprisingly, a single Hdac2 allele was sufficient for normal brain development, whereas mice with a single Hdac1 allele exhibited impaired brain architecture and perinatal lethality. The disturbed brain development was due to reduced proliferation and premature differentiation mediated by overexpression of protein kinase C delta. Together this indicates a common function of HDAC1 and HDAC2 in maintaining proper chromatin structures and highlights the unique and crucial role of HDAC2 in controlling the fate of neural progenitors during brain development. To further dissect the individual roles of these two enzymes in different contexts and various experimental settings, we designed and generated novel mouse models including HDAC1/2 biotin-tagged knock-in mice and knock-in mouse lines expressing catalytically inactive HDAC1/2 isoforms. HDAC1/2 biotin-tagged knock-in mice can be used for one-step pull-downs under stringent conditions to analyze HDAC1/2 interaction partners and associated genomic sequences. Furthermore, catalytically inactive HDAC1/2 knock-in mice will finally allow studying the contribution of the enzymatic activity in comparison to the scaffolding function of HDAC1/2.submitted by Astrid HagelkrüysZsfassung in dt. SpracheWien, Med. Univ., Diss., 2013OeBB(VLID)278985

Neuropeptide Neuromedin B does not alter body weight and glucose homeostasis nor does it act as an insulin-releasing peptide

Neuromedin B (NMB) is a member of the neuromedin family of neuropeptides with a high level of region-specific expression in the brain. Several GWAS studies on non-obese and obese patients suggested that polymorphisms in NMB predispose to obesity by affecting appetite control and feeding preference. Furthermore, several studies proposed that NMB can act as an insulin releasing peptide. Since the functional study has never been done, the in vivo role of NMB as modulator of weight gain or glucose metabolism remains unclear. Here, we generated Nmb conditional mice and nervous system deficient NmB mice. We then performed olfactory and food preference analysis, as well as metabolic analysis under standard and high fat diet. Additionally, in direct islet studies we evaluated the role of NMB on basal and glucose-stimulated insulin secretion in mouse and humans