2014 Russell & Tregoning RSV dSH
1
CONCLUSION • RSV infection leads to an IL- 1β response, from a range of cells. • The SH protein of RSV inhibits inflammasome function. • Deletion of the SH gene modulates the outcome of secondary RSV infection. • RSV ΔSH is a vaccine candidate strain which is protective to RSV infection • We propose that this is via its pore structure altering the K + flux. INHIBITION OF THE INFLAMMASOME BY THE SMALL HYDROPHOBIC PROTEIN OF RESPIRATORY SYNCYTIAL VIRUS Ryan F. Russell 1 , Jacqueline U. McDonald 1 , Ziyun Zhong 1 , Alex Bukreyev 2 , Peter L. Collins 2 , John S. Tregoning 1 1 Mucosal Infection and Immunity group, St Mary’s Campus, Imperial College London, UK. 2 Laboratory of Infectious Diseases, NIAID/NIH, MD, USA. INTRODUCTION • Respiratory syncytial virus (RSV) infects most children in the first year of life and is a major single cause of hospitalization in infants and young children. • The small hydrophobic (SH) protein of RSV has recently been described as a viral pore protein (viroporin) which forms a proton-selective channel (figure 1). • The function of SH is unknown, but SH knockout viruses are partially attenuated in vivo and are potential vaccine candidates. • Here, we present evidence that SH is involved in evasion of the host immune response, inhibiting the inflammasome. Figure 1 . Computational analysis by Gan et al (2013) suggests that the SH protein forms a pentamer containing a pore forming transmembrane region, whose diameter allows only for the passage of small molecules and ions. Further studies reveal potential ion channel activity. The SH proteins of other related viruses show inflammasome modulating activity. FIGURE 1. The SH protein of RSV encodes a viral pore protein (viroporin) that can modulate the inflammasome. GURE 2. RSV ΔSH is protective against RSV infection. FIGURE 3. RSV ∆SH induces a greater IL-1B response than wild type in vitro. FIGURE 4. RSV ∆SH is attenuated in vivo but induces a greater IL-1B response than wild type. FIGURE 5. IL-1B is produced by neutrophils and macrophages in vivo. Figure 2 . Mice were infected with either RSV A2, ΔSH or control treated, 4 weeks later all mice were challenged with RSV A2. Anti-RSV IgG before RSV challenge (A). Weight change (B), lung viral load (C), lung IL-1B (D) and lung cell number (E) after infection. Lung CD4+ (F) and CD8+ (G) T cells on day 4 and day 7. Lung RSV specific CD8 T cells on day 7 (H). Anti-RSV IgG day 7 (I). Figure 4 . Mice were infected intranasally with RSV A2 (wild type) or RSV lacking the SH gene (RSV ∆SH). Weight loss (A), lung viral load (B) and lung cell number (C) were measured after infection. Lung CD4 T (D), CD8 T (E) and DX5+ NK (G) cells were measured by flow cytometry. IL-6 (G), CXCL1/KC (H) and IL-1B (I) were measured in lung supernatants. Figure 3 . HEp-2 cells were infected with *** MOI RSV A2 or RSV ∆SH, viral load was assessed by plaque assay (A). Supernatants were collected and analysed for IL-1B level by ELISA following infection of HEp-2 cells (B), PHBE cells (C), THP-1 cells (D), and neutrophils (F). Points represent mean +/- SEM of n=3 repeats of HEp2, PHBE and THP1 cells and 3 individual PBMC and neutrophil donors. Figure 5 . Mice were infected with RSV A2 intranasally. Expression of IL-1B by Ly6G+ (neutrophils: A) and CD11c/MHCII lo/F480+ (alveolar macrophages: B) was measured by flow cytometry at various time points after infection. Mice were treated with anti-Ly6G depleting antibody (1A8) or control antibody (Con) intraperitoneally, and clodronate liposomes (CL) or empty liposomes (PL) intranasally prior to RSV A2 infection. Neutrophil (C) and alveolar macrophage (D) numbers were analysed by flow cytometry, RSV L gene (E) by RT-PCR and lung IL-1B (F), KC (G) and IL-6 (H) were measured on day 1 after infection. SH K + Casp1 NLRP3 Pro IL-1β Meet the authors! 4 7 10 0 10 1 10 2 10 3 10 4 10 5 10 6 10 7 10 8 10 9 D ays afterC hallenge R SV L gene copies per g Lung R N A Control RSV SH RSV A2 0 5 10 15 20 Anti-R SV IgG g/ml *** *** *** Control R SV SH RSV A2 0 25 50 75 100 125 Anti-R SV IgG g/ml *** *** *** 0 1 2 3 4 5 6 7 85 90 95 100 105 C ontrol RSV SH RSV A2 D ays afterC hallenge % OriginalWeight *** *** ### ### * ### * 4 7 0 5 10 6 1 10 7 2 10 7 D ays afterC hallenge Lung cell num ber * ** 4 7 0 2 4 6 8 D ays afterC hallenge C D 3+C D 8% ** ** 4 7 0 50 100 150 200 250 D ays afterC hallenge Lung IL-1 pg/ml *** *** Control R SV SH RSV A2 0 10 20 30 40 50 R SV (M 2)Specific CD 8 (% total CD8) *** * 4 7 0 2 4 6 8 D ays afterC hallenge CD3 + CD4 + (%) * ** A B C D E F G H I 0 1 2 3 4 5 6 7 90 95 100 105 110 D ays afterinfection % O riginal W eight RSV SH RSV A2 * * * 0 1 2 3 4 5 6 7 10 4 10 5 10 6 10 7 10 8 10 9 D ays afterinfection R SV L gene copies per g Lung R N A 0 1 2 3 4 5 6 7 0 100 200 300 400 500 D ays afterinfection C XC L1 pg/m l ** 0 1 2 3 4 5 6 7 0 100 200 300 400 500 D ays afterinfection IL-6 pg/m l ** 0 1 2 3 4 5 6 7 0 200 400 600 800 1000 D ays afterinfection IL-1 pg/ml 0 1 2 3 4 5 6 7 10 6 10 7 D ays afterinfection Lung cell num ber 0 1 2 3 4 5 6 7 10 4 10 5 10 6 D ays afterinfection Lung C D 4 T cells * 0 1 2 3 4 5 6 7 10 4 10 5 10 6 D ays afterinfection Lung C D 8 T cells * 0 1 2 3 4 5 6 7 10 4 10 5 10 6 D ays afterinfection Lung N K cells * A B D E F C G H I 0 20 40 60 80 0 200 400 600 800 1000 ** * * * H ours afterinfection IL-1 pg/ml 0 20 40 60 80 0 500 1000 1500 ** * * H ours afterinfection IL-1 pg/ml 0 20 40 60 80 0 5 10 15 20 H ours afterinfection IL-1 pg/ml RSV A2 RSV SH C ontrol 0 50 100 150 200 IL-1 pg/ml * 0 20 40 60 80 0 5.0 10 5 1.0 10 6 1.5 10 6 2.0 10 6 H ours afterinfection R SV pfu/m l RSV A2 RSV SH A B C D E PL + C on P L + 1A 8 C L + C on C L + 1A8 0 100 200 300 400 500 Lung IL-1 pg/ml ** *** *** PL + C on P L + 1A 8 C L + C on C L + 1A8 0 100 200 300 400 Lung IL-6 pg/m l ** ** PL + C on PL + 1A8 C L + C on C L + 1A8 0 200 400 600 800 1000 Lung KC pg/m l ** ** PL + C on PL + 1A8 C L + C on C L + 1A8 10 4 10 5 10 6 10 7 10 8 R SV L gene copies per g Lung R NA PL + C on P L + 1A 8 C L + C on C L + 1A8 0 50000 100000 150000 Ly6G + cell count *** *** 0 1 2 3 4 5 6 7 0 10000 20000 30000 40000 50000 Days afterinfection IL-1 Positive Ly6G+ *** ** *** RSV A2 Control 0 1 2 3 4 5 6 7 0 500 1000 1500 Days afterinfection IL-1 + C D 11c + M HCIloF4/80 + Cell count *** *** P L + C on PL + 1A8 C L + C on C L + 1A8 0 2000 4000 6000 C D 11c + M H C IIlo F480 + cell count ** ** * A B C D E F G H
-
Upload
ryan-russell -
Category
Documents
-
view
217 -
download
1
description
INHIBITION OF THE INFLAMMASOME BY THE SMALL HYDROPHOBIC PROTEIN OF RESPIRATORY SYNCYTIAL VIRUS
Transcript of 2014 Russell & Tregoning RSV dSH
CONCLUSION• RSV infection leads to an IL-1β
response, from a range of cells.
• The SH protein of RSV inhibits inflammasome function.
• Deletion of the SH gene modulates the outcome of secondary RSV infection.
• RSV ΔSH is a vaccine candidate strain which is protective to RSV infection
• We propose that this is via its pore structure altering the K+ flux.
INHIBITION OF THE INFLAMMASOME BY THE SMALL HYDROPHOBIC PROTEIN OF RESPIRATORY SYNCYTIAL VIRUS
Ryan F. Russell1, Jacqueline U. McDonald1, Ziyun Zhong1, Alex Bukreyev2, Peter L. Collins2, John S. Tregoning1
1Mucosal Infection and Immunity group, St Mary’s Campus, Imperial College London, UK.2 Laboratory of Infectious Diseases, NIAID/NIH, MD, USA.
INTRODUCTION• Respiratory syncytial virus (RSV) infects most children in the first year of life and is a major single
cause of hospitalization in infants and young children.
• The small hydrophobic (SH) protein of RSV has recently been described as a viral pore protein (viroporin) which forms a proton-selective channel (figure 1).
• The function of SH is unknown, but SH knockout viruses are partially attenuated in vivo and are potential vaccine candidates.
• Here, we present evidence that SH is involved in evasion of the host immune response, inhibiting the inflammasome.
Figure 1. Computational analysis by Gan et al (2013) suggests that the SH protein forms a pentamer containing a pore forming transmembrane region, whose diameter allows only for the passage of small molecules and ions. Further studies reveal potential ion channel activity. The SH proteins of other related viruses show inflammasome modulating activity.
FIGURE 1. The SH protein of RSV encodes a viral pore protein (viroporin) that can modulate the inflammasome.
4 7100
101
102
103
104
105
106
107
108
109
Days after Challenge
RSV
L ge
ne co
pies
per
g Lu
ng R
NA
Control RSV SH RSV A20
5
10
15
20
Anti-
RSV
IgG
g/m
l
*********
Control RSV SH RSV A20
25
50
75
100
125
Anti-
RSV
IgG
g/m
l
*********
0 1 2 3 4 5 6 785
90
95
100
105
ControlRSV SHRSV A2
Days after Challenge
% O
rigin
al W
eigh
t
*** ***### ###
*###
*
4 70
5106
1107
2107
Days after Challenge
Lung
cell n
umbe
r
***
4 70
2
4
6
8
Days after Challenge
CD3+
CD8%
****
4 70
50
100
150
200
250
Days after Challenge
Lung
IL-1
pg
/ml
******
Control RSV SH RSV A20
10
20
30
40
50
RSV
(M2)
Spe
cific
CD8
(% to
tal C
D8)
****
4 70
2
4
6
8
Days after Challenge
CD3+ CD
4+ (%)
***
A B C D
E F G H I
0 1 2 3 4 5 6 790
95
100
105
110
Days after infection
% O
rigin
al W
eigh
t
RSV SHRSV A2
* **
0 1 2 3 4 5 6 7104
105
106
107
108
109
Days after infection
RSV
L g
ene
copi
espe
r g
Lung
RN
A
0 1 2 3 4 5 6 70
100
200
300
400
500
Days after infection
CX
CL1
pg/
ml **
0 1 2 3 4 5 6 70
100
200
300
400
500
Days after infection
IL-6
pg/
ml
**
0 1 2 3 4 5 6 70
200
400
600
800
1000
Days after infection
IL-1
pg
/ml
0 1 2 3 4 5 6 7106
107
Days after infection
Lung
cel
l num
ber
0 1 2 3 4 5 6 7104
105
106
Days after infection
Lung
CD
4 T
cells
*
0 1 2 3 4 5 6 7104
105
106
Days after infection
Lung
CD
8 T
cells
*
0 1 2 3 4 5 6 7104
105
106
Days after infection
Lung
NK
cel
ls *
A B
D E F
C
G H I
0 20 40 60 800
200
400
600
800
1000
**
*
*
*
Hours after infection
IL-1
pg
/ml
0 20 40 60 800
500
1000
1500
**
*
*
Hours after infection
IL-1
pg
/ml
0 20 40 60 800
5
10
15
20
Hours after infection
IL-1
pg
/ml
RSV A2 RSV SH Control0
50
100
150
200
IL-1
pg
/ml
*
0 20 40 60 800
5.0105
1.0106
1.5106
2.0106
Hours after infection
RSV
pfu
/ml
RSV A2RSV SH
A B C D E
PL + Con PL + 1A8 CL + Con CL + 1A80
100
200
300
400
500
Lung
IL-1
pg
/ml **
******
PL + Con PL + 1A8 CL + Con CL + 1A80
100
200
300
400
Lung
IL-6
pg/
ml
****
PL + Con PL + 1A8 CL + Con CL + 1A80
200
400
600
800
1000
Lung
KC
pg/
ml
****
PL + Con PL + 1A8 CL + Con CL + 1A8104
105
106
107
108
RS
V L
gen
e co
pies
per
g Lu
ng R
NA
PL + Con PL + 1A8 CL + Con CL + 1A80
50000
100000
150000Ly
6G+
cell
coun
t
******
0 1 2 3 4 5 6 70
10000
20000
30000
40000
50000
Days after infection
IL-1
P
ositi
ve L
y6G
+
*** **
***RSV A2Control
0 1 2 3 4 5 6 70
500
1000
1500
Days after infection
IL-1
+C
D11
c+ MH
CI l
oF4/
80+
Cel
l cou
nt
******
PL + Con PL + 1A8 CL + Con CL + 1A80
2000
4000
6000
CD
11c+
MH
CII
lo F
480+
cell
coun
t
****
*
A B
C D
E F
G H
FIGURE 2. RSV ΔSH is protective against RSV infection.
FIGURE 3. RSV ∆SH induces a greater IL-1B response than wild type in vitro.
FIGURE 4. RSV ∆SH is attenuated in vivo but induces a greater IL-1B response than wild type.
FIGURE 5. IL-1B is produced by neutrophils and macrophages in vivo.
Figure 2. Mice were infected with either RSV A2, ΔSH or control treated, 4 weeks later all mice were challenged with RSV A2. Anti-RSV IgG before RSV challenge (A). Weight change (B), lung viral load (C), lung IL-1B (D) and lung cell number (E) after infection. Lung CD4+ (F) and CD8+ (G) T cells on day 4 and day 7. Lung RSV specific CD8 T cells on day 7 (H). Anti-RSV IgG day 7 (I).
Figure 4. Mice were infected intranasally with RSV A2 (wild type) or RSV lacking the SH gene (RSV ∆SH). Weight loss (A), lung viral load (B) and lung cell number (C) were measured after infection. Lung CD4 T (D), CD8 T (E) and DX5+ NK (G) cells were measured by flow cytometry. IL-6 (G), CXCL1/KC (H) and IL-1B (I) were measured in lung supernatants.
Figure 3. HEp-2 cells were infected with *** MOI RSV A2 or RSV ∆SH, viral load was assessed by plaque assay (A). Supernatants were collected and analysed for IL-1B level by ELISA following infection of HEp-2 cells (B), PHBE cells (C), THP-1 cells (D), and neutrophils (F). Points represent mean +/- SEM of n=3 repeats of HEp2, PHBE and THP1 cells and 3 individual PBMC and neutrophil donors.
Figure 5. Mice were infected with RSV A2 intranasally. Expression of IL-1B by Ly6G+ (neutrophils: A) and CD11c/MHCII lo/F480+ (alveolar macrophages: B) was measured by flow cytometry at various time points after infection. Mice were treated with anti-Ly6G depleting antibody (1A8) or control antibody (Con) intraperitoneally, and clodronate liposomes (CL) or empty liposomes (PL) intranasally prior to RSV A2 infection. Neutrophil (C) and alveolar macrophage (D) numbers were analysed by flow cytometry, RSV L gene (E) by RT-PCR and lung IL-1B (F), KC (G) and IL-6 (H) were measured on day 1 after infection.
SHK+
Casp1
NLRP3
Pro IL-1β
Meet the authors!
