Impact of TLR7/8 Triggering on HIV Pathogenesis

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1 University Hospital Zurich u Division of Infectious Diseases and Hospital Epidemiology Impact of TLR7/8 Triggering on HIV Pathogenesis Roberto F. Speck, MD

2 Hallmark of HIV-Infection is the Progressive CD4+ T-Cell Loss Acute HIV infection Death CD4+ T-cells/μl Clinical latency HIV RNA copies/ml Weeks Years

3 HIV Single Stranded RNA (ssrna) Triggers TLR8 Heil F et al., Science 2004

4 HIV ssrna which Act as TLR7/8 Agonists are Rich in Guanosins and Uridins Multiple fragments within the HIV genome U3 RU5 gag pol vif vpr tat rev vpu env nef

5 Multiple Fragments within the HIV Genome U3 RU5 gag pol vif vpr tat rev vpu env nef Meier A. et al., J Virol 2007

6 Questions What is the effect of TLR7/8 triggering 1. on acute HIV infection? 2. on latently infected cells? 3. on the immune system?

7 HIV ssrna Blocks HIV Replication in Ex Vivo Infected Lymphoid Tissue sshiv ssrna synthetic compounds HIV infection Monitoring of HIV replication over d Lymphatic tissue ng p24/ml 10 5 control unspecific ssrna42 Schlaepfer et al., 2006 J Immunol days post infection HIV ssrna 40

DC and NK/CD8+ T-Cells are Key for the TLR7/8 Mediated

stimulation HIV replication relative to ctrl 3 2 1 0

98 2.02 TNF-α Schlaepfer and Speck; Plos One 2008 HIV

0 control Control control TLR7/8 stimulation p<0.

8 DC and NK/CD8+ T-Cells are Key for the TLR7/8 Mediated Resistance to HIV Replication DC control TLR7/8 stimulation HIV replication relative to ctrl NK SSC control TLR7/8 stimulation IFN-γ TNF-α Schlaepfer and Speck; Plos One 2008 HIV HIV replication relative to control control Control control TLR7/8 stimulation p<0.005 TLR7/8 stimulation TLR7/8 stimulation DC TLR7/8 stimulation CD8+/NK

9 TLR7/8 triggering by HIV ssrna immune system? CD4 M CD4 CD4 CD4? latent reservoir HIV replication chronic HIV infection

10 TLR7/8 Triggering Results in the Activation of and Release of HIV from Latently Infected Myeloid- Monocytoid Cells TLR7/8 stimulation 20 latently infected cells % p24+ cells TLR7/8 stimulation Mock-treated days post-stimulation days after TLR7/8 triggering Schlaepfer et al. J Immunol, 2006

11 TLR7/8 triggering by HIV ssrna CD4 M CD4 CD4 CD4 latent reservoir HIV replication chronic HIV infection

12 What Happens when there is Sustained Triggering of the TLR7/8 Pathway? Death Acute HIV infection HIV RNA Kopien/ml copies/ml Clinical latency CD4+ T-cells/μl T-Zellen/μl

13 HIV is a Human Specific Virus Daily injections i.p. of R-848 C57BL/6 mice... [time] complete blood count cytokines histopathology functional assays (VSV)

14 Sustained Triggering TLR7 Results in CD4+ Cell decline in Peripheral Blood of Mice Baenziger S et al., Blood 2009

15 Triggering TLR7 in Mice Results in Dose- Dependent Immune Activation R-848 HIV+patients CD69 % Onlamoon N et al., Virology 2005

16 IFN type I has Properties Stimulating Immune Activation

17 Sustained Triggering TLR7 Disrupts the Lymphoid Architecture mock polyi:c R mg 0.1 mg 1 mg Baenziger S et al., Blood 2009

18 Functionally, Triggering TLR7 Results in Poor Antigen-Specific Antibody Response Baenziger S et al., Blood 2009

19 HIV ssrna Induces all the Features Characteristic of HIV Infection Uncoupled from Productive HIV Infection

20 HIV ssrna Triggering TLR7/8 Nef U3 RU5 gag pol vif vpr HIV env gp120 tat rev vpu env nef Activation of the immune system Loss of integrity of the GI-tract Inward flux of microbial components Disruption of the lymphoid system and CD4+ T-cell loss Immundeficiency AIDS Death

21 Level of Immune Activation is the Best Predictor for HIV Progression Froebel K et al., Clin Exp Immunol 2001

22 TLR7/8 triggering by HIV ssrna Dysfunction of the immune system CD4 M CD4 CD4 CD4 latent reservoir HIV replication chronic HIV infection

Nischang Institute of Neuropathology, USZ - Prof.

23 Thanks Labor - Erika Schläpfer - Stefan Bänziger - Annette Audigé - Regina Miller - Ursula Hofer - Florian Blaser - Marc Nischang Institute of Neuropathology, USZ - Prof. Adriano Aguzzi - Mathias Heikenwälder EMDO Stiftung Empiris Stiftung OPO Stiftung

24 The molecular mechanism(s) resulting in CD4+ T-cell death in HIV Infection is still unknown 1. HIV binds to, infects, and kills CD4+ T-cells. 2. progressive CD4+ T-cell depletion follows HIV infection. 3. the prevailing level of viral replication predicts the in vivo rate of CD4+ T-cell depletion. 4. the pharmacologic suppression of viral replication is followed by an increase in CD4+ T-cell counts. HIV-mediated direct killing of CD4+ T-cells

25 Speck RF et al, J of Virol 1998 HIV is highly cytopathic in vitro, but... Speck RF et al., J Virol 1998

26 but... < 0.1% of CD4+ T-cells infected with HIV in chronic HIV infection. majority of CD4+ T-cells that die, are in fact not infected.

27 Genomic structure of HIV is quite simple U3 RU5 gag Long-terminal repeat pol vif vpr tat rev vpu env Env Surface glycoprotein nef Env Transmembrane gp41 Gag Membrane associated (Matrix) protein Gag Capsid RNA Pol Polymerase Protease RNAse H Integrase

29 TLR7/8 Aktivierung hat multiple Effekte auf die HIV Pathogenese NK TLR7/8 Signal Aktivierung CD8 Immunaktivierung CD4 M CD4 CD4 CD4 HIV Replikation Immunschwäche Aktivierung des Latenten Reservoirs: HIV Freisetzung Chronische HIV Infektion

31 What other evidence do we have that our theory is correct? Mandl JN et al, Nature Medicine 2008

32 Viren müssen Wirtszellen infizieren, um sich zu vermehren zur Verfügung gestellt von Prof. A. Oxenius

33 Cleavage of the ectodomain 9 is required to generate a functional receptor Ewald SE et al, Nature 2008

35 Genomic structure of HIV is quite simple HIV genome Long-terminal repeat U3 RU5 gag pol vif vpr tat rev vpu env nef U3 R U5

36 TLR belong to the pattern recognition receptors Toll-like receptors (TLR) recognition domain out cell membrane in signaling box

37 Currently, 11 Toll-like Receptors are Known Foo Y et al., Nature Reviews Immunology, 2005

38 Reasons for immuno-activation in HIV infection Schindler M et al., Cell 2006

39 Reasons for immuno-activation in HIV infection HIV envelope gp120 aberrant signaling exchange of lipids (env+ cells & env- cell) syncytia induction contagious apoptosis Reviewed by Perfettini JL et al, Cell death and Differentiation, 2005)

40 HIV envelope gp120 results in abberrant signaling and subsequently in apoptosis gp120

41 Microbial translocation may contribute ot immune activation in HIV infection Brenchley et al, Nat Med, 2006

42 Triggering Toll-like receptor (TLR) 7/8 results in strong activation of the immune system Kontrolle Aktivierung der Toll-like Rezeptoren Toll-like Rezeptoren 7/8 Schlaepfer E. and Speck RF; Plos One 2008

43 Foster JL and JV Garcia, Retrovirology 2008

44 Direkte HIV Infektion (Zytopathizität; vorzugsweise Infektion von HIV-spezifischen CD4+ Memory Zellen) CD8+ T-Zell vermittelte Zytopathizität HIV envelope gp120 induzierter Zelltod CD4+ Zelle Chronische Immunaktivierung Progressiver CD4+ T-Zellabfall

45 Depleting dendritic cells (DC) or natural killer (NK) and CD8+ cells abolishes TLR7/8-mediated inhibition of HIV replication DC Control TLR7/8 triggering HIV replication relative HIV replication to control relative to ctrl NK Control TLR7/8 triggering TLR7/8 triggering DC control TLR7/8 triggering p<0.005 Submitted SSC IFN-γ TNF-α HIV HIV replication relative to control Control Control TLR7/8 triggering TLR7/8 triggering CD8+ and NK cells

46 Akira S, Cell 2006 Effective immune response

47 Lethal Encephalitis in MyD88 - / - Mice Infected with Herpes Simplex Virus 1 Wildtype / TLR2 - / - MyD88 - / - IFN-γ - / - Mansur et al., AJP 2005

48 Triggering TLR7 results in splenomegaly

49 Cytokine pattern does not differ between mice treated with polyi:c or R-848

50 Only partial tolerance induction in mice injected R-848 over time IL-6 IL12p40 IL-10 TNF-a

51 Schematic Structure of TLR recognition domain out cell membrane in signaling box

52 HIV Leads to a Sustained Immune Activation %CD38+ CD8+ T-cells Regina Miller, unpublished data

Human Immunodeficiency Virus

Human Immunodeficiency Virus Virion Genome Genes and proteins Viruses and hosts Diseases Distinctive characteristics Viruses and hosts Lentivirus from Latin lentis (slow), for slow progression of disease