EBOLA: niente si trasmette come la paura. La biologia del virus Ebola

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1 EBOLA: niente si trasmette come la paura 4 dicembre 2014 Sala Congressi - Asse Didattico E Complesso Universitario di Monserrato La biologia del virus Ebola Alessandra Pani Dipartimento di Scienze Biomediche Università degli Studi di Cagliari

2 La biologia del virus Ebola 1. Struttura del virione 2. Infezione e replicazione 3. Fattori di virulenza e di evasione dalla risposta immunitaria 4. Target molecolari per lo sviluppo di farmaci

3 Filovirus Filamentous or Bacillus form Vary greatly in length (up to nm) Mean Unit Length Ebola nm Marburg nm Uniform diameter of 80 nm

Genome and Proteins EBOV-Z MARV Non-segmented, negative-strand RNA Filovirus Genome 19 kb 7 Genes Nucleotide and amino acid differences b/w Marburg

4 Genome and Proteins EBOV-Z MARV Non-segmented, negative-strand RNA Filovirus Genome 19 kb 7 Genes Nucleotide and amino acid differences b/w Marburg and Ebola 55% Ebola 37 to 41% Overlaps 1 in Marburg genome VP30 to VP24 2 in Ebola genome-vp35 to VP40 & GP to VP30 Mühlberger E., Future Virology 2007

5 EboV-Z GP cleaved by FURIN Hofmann-Winkler et al.,viruses 2012

6 La biologia del virus Ebola 1. Struttura del virione 2. Infezione e replicazione 3. Fattori di virulenza e di evasione dalla risposta immunitaria 4. Target molecolari per lo sviluppo di farmaci

7 Filovirus life cycle Dolnik et al., Cell. Mol. Life Sci. 2008

8 Dolnik et al., Cell. Mol. Life Sci Miller & Chandran, Curr Opinion Virol 2012 Kondratowicz et al., Proc Natl Acad Sci USA 2011 Hofmann-Winkler, Viruses 2012

9 Lectins involved in Filovirus attachment GP-binding lectins ASGPR-1 hmgl hepatocytes Tissue distribution monocyte-derived immature dendritic cells intermediate precursors of macrophages DC-SIGN DC-SIGNR LSECtin dendritic cells fetal macrophages decidual macrophages alveolar macrophages platelets activated primary B-cells endothelial cells in the placenta endothelial cells in the liver and lymph node sinuses sinusoidal endothelial cells in liver, lymph nodes and bone marrow thymic dendritic cells monocyte-derived macrophages peripheral blood cells

10 Cellular endocytic pathways and factors implicated in Filovirus entry Bhattacharyya et al., Virology 2010 Saeed et al., PLoS Pathog 2010 Carette et al., Nature 2011 Cote et al., Nature 2011

11 Filovirus life cycle Dolnik et al., Cell. Mol. Life Sci. 2008

12 GP expression in Ebola virus Transcriptional RNA Editing At a series of 7 U s on the GP RNA insert a non-template coded adenosine: 20% of GP mrna is edited GP 80% of GP mrna is not edited sgp EBOV GP gene encodes 2 products: 2 ORF (MARV GP gene encodes 1 product: 1 ORF) GP-RNA Editing Over-expression of GP Cytotoxicity and eventual cell death GP expression and cytotoxicity can be regulated by virus through transcriptional RNA editing and secretory-gp expression Volchkov et al., Science 2001

13 Filovirus life cycle Dolnik et al., Cell. Mol. Life Sci. 2008

14 La biologia del virus Ebola 1. Struttura del virione 2. Infezione e replicazione 3. Fattori di virulenza e di evasione dalla risposta immunitaria 4. Target molecolari per lo sviluppo di farmaci

15 GP EboV virulence factors: GP and sgp 1. Specific region of GP induces cytotoxic effects in endothelial cells -Rapid release of vasoactive agents from infected cells -Induces cell rounding and detachment from extracellular matrices -Increases cell membrane permeability 2. Specific region of GP contribute to evasion of host immunity -Possible immunosuppressive sequence in GP 2 : blocks lymphocyte mitogen-stimulated proliferation in vitro sgp 1. Inhibits early activation of neutrophils -Binds to neutrophils via CD16b cell surface receptor 2. Sequesters neutralizing antibodies Yang et al., Nature Med 2000 Simmons et al., J Virol 2002 Marzi et al., Virology 2006

EboV virulence factors: VP35 and VP24 Dolnik et al., Cell. Mol. Life Sci. 2008 Ramanan et al.

16 EboV virulence factors: VP35 and VP24 Dolnik et al., Cell. Mol. Life Sci Ramanan et al., Viruses 2011 Wei Xu et al., Cell Host & Microbs 2014 VP35: No IFN-α/β VP24: No IFNantiviral effectors

Multiple funtions of IFN-α and IFN-β (antiviral-ifns) 1 2 Antiviral state of host cells 3 Activation of immune cells 5 Induction of IFN-γ (immune-ifn) cell-mediated immune

17 Multiple funtions of IFN-α and IFN-β (antiviral-ifns) 1 2 Antiviral state of host cells 3 Activation of immune cells 5 Induction of IFN-γ (immune-ifn) cell-mediated immune response 5 5 Basler et al., Proc Natl Acad Sci USA 2000 Basler & Amarasinghe, J Interferon Cytokine Res 2009 Ramanan et al., Viruses 2011 Wei Xu et al., Cell Host & Microbs

18 La biologia del virus Ebola 1. Struttura del virione 2. Infezione e replicazione 3. Fattori di virulenza e di evasione dalla risposta immunitaria 4. Target molecolari per lo sviluppo di farmaci

19 EboV molecular targets for the therapy and/or prevention of Ebola infections vglycoprotein GP (adhesion/penetration) cnpc1 (necessary for uncoating) vrnapol L (transcription/replication) VP35 (transcription/replication and IFN inhibition) VP40 (transport/assembly) VP24 (assembly and IFN inhibition)

Drugs and vaccines in clinical trials with support for further development according to the Centers for Disease Control and Prevention Animals Trials Healthy volunteers Small group of patients Large

20 Drugs and vaccines in clinical trials with support for further development according to the Centers for Disease Control and Prevention Animals Trials Healthy volunteers Small group of patients Large group of patients Approved for use ZMapp GP: triple mabs cocktail Brincidofovir RNA-pol (??): nucleoside analog; broad spectrum - DNA viruses TKM-Ebola RNApol: sirna Favipiravir RNApol: nucleoside analog; chain terminator; anti-flu approved AVI-7537 BCX4430 ChAd3 VSV-EBOV VP24: anti-sense oligomer RNApol: nucleoside analogue; broad spectrum - RNA viruses Drugs Vaccines Kondratowicz & Maury, Future Microbiol 2012 Nature Reviews Drug Discovery 2014 Gao, Drug Discov Ther 2014 Cohen, Science 2014

Ebola therapy protects severely ill monkeys

Propojení výuky oborů Molekulární a buněčné biologie a Ochrany a tvorby životního prostředí OPVK (CZ.1.07/2.2.00/28.0032) Ebola therapy protects severely ill monkeys Nature 514, 41 43 2 October 2014 Published