aspergillosis patients support meeting august 2011
TRANSCRIPT
NICOLA SMITHNATIONAL ASPERGILLOSIS CENTRE
UHSMMANCHESTER
Support Meeting for Aspergillosis Patients
Fungal Research Trust
Nicola Smith
The University of Manchester, Manchester Academic Health Science Centre, University Hospital of South
Manchester, UK
Genetic Susceptibility to Aspergillosis
Introduction: Aspergillosis (1)
• Disease caused by fungus – Usually A. fumigatus
• Causes multiple types of lung disease– Allergic (ABPA, SAFS)
– Chronic (CCPA, CNPA, CFPA)
– Invasive (IPA)
• Project focuses on chronic and allergic diseases
Genetic Susceptibility in Aspergillosis
• ABPA occurs in families – Shah et al., 1990; Shah et al., 2008
• Genetic associations found in literature
My Project• Investigating possible genetic associations • Find genes underlying susceptibility to
aspergillosis
DNA, Genes & Proteins
• Genes are made of DNA• Genes are the blueprint
for proteins • Proteins are the building
blocks of our bodies
Fig: http://www.bioteach.ubc.ca/Bioinformatics/humangenome
• Genes (and proteins) vary between people– We look different (eye, hair colour etc)
• Differences in genes can also affect susceptibility to disease
• When cells in the body make proteins we say that the gene is being expressed
• Some genes are expressed all the time• Others are turned on and off as required
• Gene expression can be turned on or off by various factors
Gene Expression (1)
Example: Person gets an infection • Cells see germs – gene expression of anti-germ
genes is turned on• Cells produce proteins to fight of the germ• Germ is killed by proteins• Cells no longer see germs – gene expression is
turned off• Cells stop making anti-germ protein
Gene Expression (2)
Immune cell
Protein
Germ
Gene Expression:
Do the cells of aspergillosis patients respond differently to those from healthy volunteers?
• Which genes are expressed in aspergillosis?
• Macrophages: cells in blood, fight germs• Aspergillus: fungus (germ) causing aspergillosis
• Grow macrophages and Aspergillus together and look at gene expression
Gene Expression and Aspergillosis (1)
Aspergillus
Macrophage
• Changes in expression after exposure to fungus = genes are important in fighting fungus
• Look at cells from healthy volunteers and patients
• Differences in expression between the groups = may be important in disease susceptibility
• Differences may be at before or after exposure to fungus
Gene Expression and Aspergillosis (2)
Gene expression is measured at 30min, 1hr, 3hr, 6hr and 9hr – how does this relate to the fungus?
Fungal growth: resting conidia (RC) germinating conidia (GC) germtube (GT) hyphae (H)
Counted the amount of fungus at each stage over time
Timepoints for gene expression (1)
Gene expression is measured at 30min, 1hr, 3hr, 6hr and 9hr – how does this relate to the fungus?
3hr – mostly resting conidia
6hr – mostly germtubes
9hr – mostly hyphae
Timepoints for gene expression (2)
Method
Ficoll prep
PBMCs stored in liquid nitrogen
Cultured for 12-15 days to differentiate to macrophages (~2x105)
24well plate – one plate per timepoint
0hr timepoint – investigate gene expression
Aspergillus spores added (4x105)
30min, 1hr, 3hr, 6hr, 9hr timepoints - Investigate gene expression
Macrophages and Aspergillus cultured together
Heparinised Blood
Macrophages
PBMCs
Ficoll prepped blood
Plasma
Ficoll
Granulocytes
PBMCs thawed and plated out (2x106)
Gene Expression Results
I studied the expression of 84 genes!
Fold regulation in ABPA (1)A
DO
RA
2A
C5 C8A
CA
MP
CA
SP
1
CC
R3
CD
14 CD
55
CH
UK
CR
P
CY
BB
DE
FB
4
DM
BT
1
FN
1
HM
OX
1
IFN
A1
IFN
B1
CC
L2
CD
1DCA
SP
4
CO
LEC
12 CX
CR
4
-40
-35
-30
-25
-20
-15
-10
-5
0
5
10
Gene
Fo
ld r
egu
latio
n (c
om
par
ing
to 0
hr)
30min
1hr
3hr
6hr
9hr
Fold regulation in ABPA (2)
IKB
KB
IL1
2R
B2
IL1
A
IL1
B
IL1
F1
0
IL1
F5
IL1
F6
IL1
F7
IL1
F8
IL1
F9
IL1
R1
IL1
RA
P
IL1
RA
PL
2
IL1
RL
2 IL1
RN IL6
IRA
K2
IRA
K1
IL1
R2
IL1
0
IFN
GR
2
IFN
GR
1
-15
-10
-5
0
5
10
Gene
Fo
ld r
egu
latio
n (c
om
par
ing
to 0
hr)
30min
1hr
3hr
6hr
9hr
IRF1LALBA
LBPLTF
LY96 LYZMAPK14 MAPK8
MIFMYD88 NCF4
NFKB1NFKB2
NFKBIANLRC4 NOS2
PGLYRP1PGLYRP2
PGLYRP3PPBP
PROCPTAFR
-15
-10
-5
0
5
10
15
Fold regulation (comparing to 0hr)
Gene
Fold regulation in ABPA (3)
30min
1hr
3hr
6hr
9hr
Fold regulation in ABPA (4)
SE
RP
INE
1
TLR
8
TLR
9
TN
F
TR
AF
6
RP
L13
A
SE
RP
INA
1
SF
TP
D
TG
FB
1
TLR
1
TL
R1
0
TL
R2
TLR
4
TL
R6
HP
RT
1
B2
M
TN
FRS
F1
A
TO
LLIP
TR
EM
1
S1
00A
12
TLR
3
-70
-60
-50
-40
-30
-20
-10
0
10
20
Gene
Fo
ld r
egu
latio
n (c
om
par
ing
to 0
hr)
30min
1hr
3hr
6hr
9hr
RED: more expression in ABPA (2)
GREEN: less expression in ABPA (12)
ABPA 0hr vs Asthma 0hr
>2-fold higher expression in ABPA
>2-fold lower expression in ABPA
Expression before Exposure: ABPA
RED: more expression in CCPA (4)
GREEN: less expression in CCPA (5)
CCPA 0hr vs Healthy 0hr
>2-fold higher expression in CCPA
>2-fold lower expression in CCPA
Expression before Exposure: CCPA
Less expression in ABPA:• 9 genes involved in IL1 pathway• TREM1: receptor
Less expression in CCPA:• TLR10, TLR3, TLR1, TLR8: receptors
Expression before Exposure:ABPA and CCPA
Less expression in CCPA than controls:
• TLR10, TLR3, TLR1, TLR8
• TLRs:
• are receptors on the cell surface
• are important in recognising germs
• tell the cell to respond to the germ (to fight it off)
• Less expression fewer receptors harder for cell to recognise fungus fungus grows get disease
Expression before Exposure: TLRs
Less expression in ABPA than in controls:
• 9 genes involved in IL1 pathway
• IL1 pathway:
• Proinflammatory – leads to inflammation
• Inflammation is often useful in fighting off fungus
• Uncontrolled inflammation can be a problem
• What happens in this pathway over time?
Expression before Exposure: IL1 pathway
• Asthma (control) - expression alters in response to fungus• ABPA - expression remains low
• ABPA cells don’t respond to presence of fungus less inflammation less fungal death disease
Expression over time: IL1 pathway
IL6 IL1A IL1B
• TNF expression increases over time in all groups (CCPA, ABPA and controls)
• TNF is proinflammatory – is important in fighting fungus
Expression over time
Genetic Variation: Are there similar differences in the
genes (DNA)?
• DNA is like a string of letters (A, T, G, C)• The letters in the string tell the body how and
when to make protein
• Small changes in the letters (SNPs) can change:• When a protein is made• How much of a protein is made• Whether a protein works or not (or how well)
Genetic Variation
ATGGGTAATGCCATGTCAC = normal proteinATGGGTAACGCCATGTCAC = more proteinATGGATAATGCCATGTCAC = non-functional protein
Example: STAT6
Example: MBL
Protein Function• Binds to germs, helps cells see them
SNPs cause:• Low/High expression levels
– Low expression = less protein to fight infection
• Functional/Non-functional protein– Non-functional protein = can’t fight infection
• Associated with CPA (Vaid et al., 2007; Crosdale et al., 2001)
• Most SNPs have 2 possible letters (e.g. C and G)
• Count how many patients and how many controls and each letter:• More C in patients than in controls• Statistics prove it’s not due to chance• SNP is associated with disease (C in particular)
Genetic Variation and Disease
Genetic Variation Results (1)
CCPA 0hr vs Healthy 0hr
>2-fold higher expression in ABPA
>2-fold lower expression in CCPA
• TLR1: SNP associated with CCPA• TLR10: SNP associated with ABPA+CPA
• Both show low expression in CCPA• Do the SNPs cause this?
Genetic Variation Results (2)
• IL6: 2 SNPs associated with ABPA
• Differences are seen in IL6 expression by ABPA and control cells
• Do the SNPs cause this difference?IL6
Genetic Variation Results (3)
ABPA 0hr vs Asthma 0hr
>2-fold higher expression in ABPA
>2-fold lower expression in ABPA
• TREM1: 1 SNP associated with SAFS
• Lower expression by ABPA than control cells – before and after exposure to fungus
• Does the SNP cause this difference?
Genetic Variation Results (4)IL1RN: • 1 SNP associated with CCPA• 2 SNPs associated with ABPA+CPA• 1 SNP associated with ABPA
• Expression increases over time: must be important in response – do the SNPs affect the function?
Genetic Variation Results (5)• Dectin-1: receptor that recognises A. fumigatus
• 2 SNPs associated with CCPA• 1 SNP associated with ABPA+CPA• 1 SNP associated with ABPA• 1 SNP associated with SAFS
• SNPs may affect the ability of the cells to recognise and respond to the fungus
• Expression of Dectin-1 was not investigated
So what?• We can find differences between patients and
controls – but so what?
• Differences in expression over time: tells us which genes are important in fighting the fungus (and preventing the disease)
• Differences between patients and controls: suggests genes that may be involved in disease susceptibilty
Knowledge of these helps us know which proteins may be useful drug targets/therapies…
How?Knowledge of these helps us know which proteins may
be useful drug targets/therapies… how?
This is a long way in the future, but…
• If a protein is shown to be important and is reduced in a patient, it may be possible to replace this protein as a therapy
• If a receptor is shown to be important in recognition of the fungus, it may be possible to boost the response of this receptor with drugs
Summary• DNA Genes Proteins• Small changes in DNA (SNPs) can affect protein
expression or function• Differences in expression can be seen between ABPA
and CCPA patients and controls• SNPs can be found in these and other genes
Future work:• Discover the function of these SNPs• Use this information to further understanding
aspergillosis
AcknowlegementsPatients
Supervisors:
• Dr Paul Bowyer
• Dr Angela Simpson
• Dr David Denning
Advisor:
• John Curtin
Blood Processing:
• Liz Hadley
• Lucy Yates
Recruitment / clinics:
• Dr David Denning
• Dr Robin Gore
• Dr Rob Niven
• NWLC nurses
• NAC nurses (Georgina & Debbie)
• Marie Kirwan
• Marian Denson
Funding / Resources:
• MRC
• NHS