1 Sample & Assay Technologies Isolation Functionalization Quantification Quantification and Profiling of miRNAs: Challenges and Strategies Subu Yerramilli, Ph.D. Associate Director R&D [email protected]The second in a series of QIAGEN webinars on miRNA 2011
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1 Sample & Assay Technologies
Isolation FunctionalizationQuantification
Quantification and Profiling of miRNAs:Challenges and Strategies
The second in a series of QIAGEN webinars on miRNA 2011
2 Sample & Assay Technologies
Isolation FunctionalizationQuantification
QIAGEN miRNA Series1. Introduction to miRNABiogenesis and genomic organizationGeneration of miRNA diversity, regulation of expressionNormal function and mis-regulation in diseaseSample handling and profiling from FFPE and SerumIntroduction to quantification and functional genomics
Recorded version on QIAGEN website (coming soon)
3 Sample & Assay Technologies
Isolation FunctionalizationQuantification
QIAGEN miRNA Series2. Quantification and Profiling of miRNAs:Why quantify?Challenges and MethodologiesThe miScript SystemProfiling the miRNA-OmeData Analysis
Upcoming webinar (March 9th 2011):3. Small RNAs With Big Impact:
Functional Studies of miRNAs
Sample & Assay Technologies- 4 -
Why Quantify miRNA?
Virtually every publication included quantification experiments
Changes in miRNA correlated with gene expression changesin development, differentiation, signal transduction, infection, aging, and disease
Known miRNAs in Sanger DB miRNA publications in Medline
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5 Sample & Assay Technologies
miRNA Quantification Challenges
� Short sequences: ~16-26 nt
� Presence of miRNA isoforms� Near identical with ~1-3 nt differences� These differences can be any where in the sequence length� Potential for some degree of cross reactivity (Depends on the location of these differences)
� miRNAs with less than ideal GC% (very low or very high)
Quantification of miRNA, mRNA and sn/snoRNA:From a Single cDNA Reaction
Template: 1 ng HeLa cDNA/PCR
15 Sample & Assay Technologies
Different 5 ′ & 3′ end extensions of Pre-miRNAs
Different 5 ′ & 3′ end extensions of Pre-miRNAs
miR-215
150125
100
75
M 1 10 10
Jurkat
HeLa
M 1 10 1 10
Jurkat
HeLa
miR-148b
150125
100
75
85100miR-148b
Bottom strand (3')
84147miR-215
Top strand (5')
Mature specific
Precursor specific
PCR Product size (Predicted; bp)
miRNA
85100miR-148b
Bottom strand (3')
84147miR-215
Top strand (5')
Mature specific
Precursor specific
PCR Product size (Predicted; bp)
miRNA
150125
100
75
M 1 10 1 10
Jurkat
HeLa
miR-345 miR-423
150125
100
75
M 1 10 1 10
Jurkat
HeLa
85105miR-423
Bottom strand (3')
84145miR-345
Top strand (5')
Mature specific
Precursor specific
PCR Product size (Predicted; bp)
miRNA
85105miR-423
Bottom strand (3')
84145miR-345
Top strand (5')
Mature specific
Precursor specific
PCR Product size (Predicted; bp)
miRNA
Gel analysis of miScript PCR products
miR-215miR-215
150125
100
75
150150125125
100100
7575
M 1 10 10
Jurkat
HeLa
M 1 10 1 10
Jurkat
HeLa
miR-148b
150125
100
75
M 1 10 1 10
Jurkat
HeLa
M 1 10 1 10
Jurkat
HeLa
miR-148b
150125
100
75
miR-148b
150125
100
75
150150125125
100100
7575
85100miR-148b
Bottom strand (3')
84147miR-215
Top strand (5')
Mature specific
Precursor specific
PCR Product size (Predicted; bp)
miRNA
85100miR-148b
Bottom strand (3')
84147miR-215
Top strand (5')
Mature specific
Precursor specific
PCR Product size (Predicted; bp)
miRNA
85100miR-148b
Bottom strand (3')
84147miR-215
Top strand (5')
Mature specific
Precursor specific
PCR Product size (Predicted; bp)
miRNA
85100miR-148b
Bottom strand (3')
84147miR-215
Top strand (5')
Mature specific
Precursor specific
PCR Product size (Predicted; bp)
miRNA
150125
100
75
M 1 10 1 10
Jurkat
HeLa
miR-345 miR-423
150125
100
75
M 1 10 1 10
Jurkat
HeLa
85105miR-423
Bottom strand (3')
84145miR-345
Top strand (5')
Mature specific
Precursor specific
PCR Product size (Predicted; bp)
miRNA
85105miR-423
Bottom strand (3')
84145miR-345
Top strand (5')
Mature specific
Precursor specific
PCR Product size (Predicted; bp)
miRNA150125
100
75
M 1 10 1 10
Jurkat
HeLa
miR-345 miR-423
150125
100
75
M 1 10 1 10
Jurkat
HeLa
150125
100
75
M 1 10 1 10
Jurkat
HeLa
miR-345
150125
100
75
M 1 10 1 10
Jurkat
HeLa
150125
100
75
150150125125
100100
7575
M 1 10 1 10
Jurkat
HeLa
M 1 10 1 10
Jurkat
HeLa
miR-345 miR-423
150125
100
75
M 1 10 1 10
Jurkat
HeLa
miR-423miR-423
150125
100
75
150150125125
100100
7575
M 1 10 1 10
Jurkat
HeLa
M 1 10 1 10
Jurkat
HeLa
85105miR-423
Bottom strand (3')
84145miR-345
Top strand (5')
Mature specific
Precursor specific
PCR Product size (Predicted; bp)
miRNA
85105miR-423
Bottom strand (3')
84145miR-345
Top strand (5')
Mature specific
Precursor specific
PCR Product size (Predicted; bp)
miRNA
85105miR-423
Bottom strand (3')
84145miR-345
Top strand (5')
Mature specific
Precursor specific
PCR Product size (Predicted; bp)
miRNA
85105miR-423
Bottom strand (3')
84145miR-345
Top strand (5')
Mature specific
Precursor specific
PCR Product size (Predicted; bp)
miRNA
Gel analysis of miScript PCR products
Only Mature miRNAs are Amplified:Pre-miRNAs are Not Co-Amplified
16 Sample & Assay Technologies
Data Normalization:Constant Expression Levels of Normalizer Non Coding RNAs
677769U91SCARNA17
6080U17A/B, E1SNORA73A
9303U25SNORD25
26826U6BRNU6B
26833U5ARNU5A
26869U1RNU1
GENE ID
ALSO KNOWN AS
OFFICIALSYMBOL
Expression of miScript control sn/snoRNAs: Human tissue Panel
17 Sample & Assay Technologies
QIAGEN Solutions for miRNA Research
Characterizing the miRNA- omeUsing the miScript System
18 Sample & Assay Technologies
How much RNA is Needed for miRNA Quantification?Depends on the Detection Limit of the System and miRNA Abundance
� System sensitivity: � miScript RT-PCR can detect 10 copies per PCR
� RNA abundance:� A ‘typical’ cell contains ~15-30 pg of total RNA� miRNA expression levels vary from as low as 10 copies/cell to
as high as 35,000 copies/cell
� How much template is needed to detect an abundant miRNA?� An abundant miRNA should be detectable with 10-15 pg of template
19 Sample & Assay Technologies
� What about miRNAs expressed at ~10-100 copies/cell?� Considering that 10x more template result in a 3.3 CT shift� Use 10-20 times more template (0.1 ng-0.2 ng) to detect rare miRNAs
� To be able to ‘call with certainty’ a miRNA is ‘not expressed’� use >20x more RNA (0.5 to 1.5 ng)
� As a guideline, consider using ~ 50 pg to 500 pg template/PCR� Up to 20,000 PCR reactions per 1 µg miScript RT reaction
� Desirable to use an RT system which tolerates a broad range of input RNA
� miScript allows 10 pg - 1µg in put RNA into RT reaction
How much RNA is Needed for miRNA Quantification?Depends on the Detection Limit of the System and miRNA Abundance
20 Sample & Assay Technologies
Expression of miRNAs in Jurkat cells
Total number of miRNAs tested : 328
Total number of miRNAs that show expression in Jurkat : 110
Total number of miRNAs showed >3.5 fold regulation: 30
21 Sample & Assay Technologies
Jurkat Cell Model System
Jurkat cells:� Acute T cell Leukemia cell line� Used as a model cell line for studying T-cell activation
PMA (Phorbol Myristyl Acetate)� Activates PKC which in turn activates NFkB & AP1
Ionomycin (Calcium Ionophore)� Activation of Ca2+/calmodulin-dependent signaling pathways,
which in turn activates NFAT
Jurkat cells
PMA PMA+ Ionomycin
One signal Two signalsNo signal
No Treatment
22 Sample & Assay Technologies
Activated Jurkat Cells:Differential Regulation of miRNAs
Measured at 24 hours, normalized to U6B ncRNA
miR-146a, miR-155 upregulated upon activation
23 Sample & Assay Technologies
3T3L1 Fibroblast Differentiation into Adipocytes
Preadipocyte Mature adipocyte
Nucleus
Lipid droplets
� Differentiation Induction by treatment with Insulin, Dexamethasone & Methylisobutylxanthine
Day -2 0 2 4 6 9 12 14
3T3L1 cells
Differentiation
Induction
InsulinNormal Growth medium
100%
Confluent
Differentiation
Induction
24 Sample & Assay Technologies
A Novel Two-Step miRNA Profiling Strategy
* up to n=10 samples used successfully
17730Conventional screening
60%% reduction
6912Two-step approach
Total # of PCRs
(n=10 Samples)
miRNA Profiling
Approach
RNA sample-1RNA Sample-2RNA Sample-3RNA Sample-n
cDNA-1cDNA-2cDNA-3cDNA-n
Pooled cDNA
miRNA profiling by miScript PCR system
miRNAs Expressed
miRNAs Not Expressed
miRNA profiling on individual samples
X
RNA sample-1RNA Sample-2RNA Sample-3RNA Sample-n
cDNA-1cDNA-2cDNA-3cDNA-n
Pooled cDNA
miRNA profiling by miScript PCR system
miRNAs Expressed
miRNAs Not Expressed
miRNA profiling on individual samples
X
****
25 Sample & Assay Technologies
Condensed miRNA Profiling by RT-PCRTracking miRNA Changes in 3T3-L1 Cells During Differentiation
cDNAPool
� What miRNAs are expressed in resting, proliferative and differentiated Adipocytes?
� Profiling using 591 miScript primer assays (miRBase v12, Mouse)
Total RNA
miScript RT
Day -2 0 2 4 6 9 12 14
Differentiation
Induction
miRNAs Expressed = 192 (32%)No expression = 399
192 miRNAs Expressed
399 miRNAs Not expressed
192 miRNAs Expressed
399 miRNAs Not expressed
26 Sample & Assay Technologies
Relative Expression of Selected Mature and pre-miRNAsNIH 3T3L1: Day 1 vs. Day 9
General trend is that change in mature miRNA correlates with pre-miRNAbut there are exceptions which point to differences in processing efficiency/turnover
� Absolute quantification� Absolute input copies, based on a standard curve
� Relative quantification� Comparative CT method
(also known as the 2-∆∆CT method)
� Selection of internal control
� Selection of calibrator
(e.g. untreated control or normal sample)
� Assumes that the PCR efficiency of the target gene is similar to the internal control gene (and that the efficiency of the PCR is close to 1)
� Fold change = 2-∆∆CT
= [{gene of interest (CT) – internal control (CT) sample A} –
{gene of interest (CT) - internal control (CT) sample B}]
(1) Schmittgen TD, Livak KJ.(2008):Analyzing real-time PCR data by the comparative C(T) method. Nat Protoc.;3(6):1101-8
(2) Livak, KJ, and Schmittgen, TD.(2001): Analysis of Relative Gene Expression Data Using Real-Time Quantitative PCR and the 2-∆∆CT Method METHODS 25, 402–408
(3) www.Gene-Quantification.info
CT = 23.8
28 Sample & Assay Technologies
� cDNA Synthesis � 2 hours
� Load Plates � 2 minutes
� Run 40 cycle qPCR Program � 2 hours
� Upload and Analyze Data� 15 minutes
How RT2 miRNA PCR Arrays Work
29 Sample & Assay Technologies
RT2 Data Analysis
� Web-Based Software� No installation needed
� From Raw Ct Values to Fold Change Results� Using ∆∆C(t) Method
Only Pre-miR-7-1 stem loop shows detectable expres sion in HeLa S3 cells
10 ng cDNA/PCR
38 Sample & Assay Technologies
Expression of Let-7a Precursors in Different Tissues
02468
10121416
Bra
in
Hea
rt
Ova
ry
Adi
pose
Kid
ney
Lung
Tes
tes
Live
r
Rel
ativ
e E
xpre
ssio
n Pre-Let-7a-1
Pre-Let-7a-2
Pre-Let-7a-3
Relative Expression = 2 -∆CT X 105
Normalizer Used: U6B10 ng cDNA /PCR
39 Sample & Assay Technologies
Expression of miR-18a and its PrecursorA member of the miR-17-92 Cluster (13q31.3)
5
7
9
11
13
15
17A
dipo
se
Bla
dder
Bra
in
Cer
vix
Col
on
Hea
rt
Kid
ney
Live
r
Lung
Pla
cent
a
Pro
stat
e
Ske
leta
l
Spl
een
Tes
tes
Thy
roid
Ova
ry
∆CT Pre-miR-18a
∆CT mature-miR-18a
∆C
T (
Rel
ativ
e to
U6B
)
gDN
AAdipose Brain Heart Liver Ovary HeLa L
P M P M P M P M P M P M P 125 bp
75 bp
50 bp
P) Pre-miR-18a specific M) Mature miR-18a specific
Guil, S & Ca´ceres, JF., (2007) Nat Struct Mol Biol;14(7):591-6.
Pre-miR-18a Specific Product
Mature miR-18a Specific Product
40 Sample & Assay Technologies
miScript System
Circulating miRNA in Serum and Plasma
41 Sample & Assay Technologies
Workflow for Quantification of Circulating miRNA
Blood collection & plasma/serum
isolation
RNA Prep
+ Cel-miRNAs
cDNA synthesis
Real-time PCR
Data analysis &
normalization
QIAzol Bind Wash Elute
AAAAAAA
TTT
AAAAAAATTT
miRNeasy
Serum & Plasma Protocol
miScript RT
RT2-miRNA RT
miScript (single miRNA Assays)
RT2 miRNA PCR Arrays
Data analysis tools – FREE!
42 Sample & Assay Technologies
Circulating miRNA: Special Considerations
� Serum or Plasma? Be consistent in collection and handling.
� Take steps to insure minimum cell lysis or carryover of cells
� Use an exogenously spiked in normalizer (e.g. C. elegans spike in)
� No ‘normal’ levels of any RNA established
� Platelets may contain miRNAs (Landry P et al 2009)
� For plasma
� Do NOT use heparin as anticoagulant as it can interfere in RTPCR
� Appropriate caveats in quantifying circulating miRNAs as markers
� Use an optimized isolation protocol (e.g. miRNeasy Plasma protocol)
Landry, P., et. al.,(2009) Existence of a microRNA pathway in anucleate platelets. Nat Struct Mol Biol 16:961
43 Sample & Assay Technologies
Summary
� Challenges in miRNA quantification
� miRNA quantification by real time PCR
� Available tools for miRNA profiling experiments
� Critical aspects of template requirements
� Examples of miRNA profiling studies
� Precursor detection� Measuring the relative levels of mature miRNA and its precursor� Identifying the genetic locus responsible for a given miRNA expression in a cell
� RT2 miRNA arrays for simple and easy miRNA Profiling