a novel systems biology approach to sarcopenia: new...
TRANSCRIPT
Ying Ge, PhDAssociate Professor
Department of Cell and Regenerative BiologyDepartment of ChemistryHuman Proteomics Program
University of Wisconsin-Madisonhttp://crb.wisc.edu/yinglab/
Email: [email protected]
A Novel Systems Biology Approach to Sarcopenia:
New Molecular Insights Enabled by Cutting-edge Technologies
28th ANNUAL COLLOQUIUM ON AGING, 9-27-2016
Outline
What is sarcopenia?
What are skeletal muscle structure & function?
What is systems biology?
What are proteomics & mass spectrometry?
How could proteomics-based systems biology help understand and treat sarcopenia?
Conclusions and future directions
Sarcopenia: an age-related loss of skeletal muscle
mass, strength, and function.
What is sarcopenia?
http://myheart.net/articles/sarcopenia-age-related-muscle-loss/
Normal
muscle
https://en.wikipedia.org/wi
ki/Muscle_atrophy
Atrophied
muscle
(Muscle atrophy: muscle mass decrease.)
Physically inactive people can lose
as much as 3% to 5% of their
muscle mass each decade after age
30.
The loss of muscle mass and strengthresulted from Aging.
What is sarcopenia?
Some signs of old age are obvioushttp://health.howstuffworks.com/wellness/aging/aging-
process/sarcopenia.htm http://www.hughston.com
The loss of muscle mass (A) and function (B) from aging.
What is sarcopenia?
1. Jubrias SA, Odderson IR, et al. Pflugers Arch – Eur J Physiol. 1997.
2. Payne AM, Dodd LS, et al. J Appl Physiol. 2003.
24 year-old 65 year-old
(A) (B)
Molecular mechanisms underlying decrease in intrinsic
contractile function with age remain unknown.
What is the impact of sarcopenia?
• Sarcopenia is very common in older adults and
associated with disability, falls, fractures, loss of
independence and mortality.
• Sarcopenia is a major health problem given the
prevalence of aging population (healthcare costs
estimated at > $18 billion/year in the US).
http://fightsarcopenia.com/ von Haehling S et al. 2010;
Janssen et al. 2002, 2004.
Sarcopenia: A major public health problem
Major health problem,
poorly understood,
difficult to be prevented
and treated
Courtesy: Chris Adams
Urgency to understand and treat sarcopenia
New Horizons in the Pathogenesis, Diagnosis and Management of Sarcopenia
Avan et al. Age Ageing, 2013, 42, 145-150
“Sarcopenia is currently a major focus for drug
discovery and development.”
“A deeper understanding of the molecular and
cellular mechanisms of sarcopenia, derived
from both human and animal studies, has
great potential to identify novel targets for
drug and other treatment strategies as well as
to develop better biomarkers to monitor the
efficacy of various interventions.”
A life course approach to sarcopenia
Sayer et al. J. Nutr Health Aging 2008 Avan et al. Age Ageing, 2013
The potential for prevention and intervention at earlier stages
of life before sarcopenia is present.
Healthy aging!
Mader, Syliva S. Human Biology. New York, NY: McGraw-Hill (2008).
What is skeletal muscle?
- Is a form of striated muscle
tissue
- Has striated, tubular,
multinucleated fibers
- Usually attached to skeleton
(bones) by bundles of collagen
fibers knowns as tendons
- Under the voluntary control of the
somatic nervous system
- Composed of muscle fibers,
myofibrils
The basic functional unit of the
muscle fiber is sarcomere, mainly
composed of actin and myosin
filaments.
myofibrils
Skeletal
muscle:
http://anatomy-body.us/
Human skeletal muscle system
Z-discs
Myofibril
Sarcomere
Myofilaments
Overview of skeletal muscle structure
Skeletal muscle
cell
Modified based on Peng et. al. MCP 2014
Myofilaments – “Contractile Apparatus”
Thin
Filament
Thick
Filament
S-1: myosin catalytic head domain (head)
S-2: myosin filament forming domain (Rod)
ELC: myosin essential light chain
RLC: myosin regulatory light chain
RLC
TnI: Troponin I
TnC: Troponin C
TnT: Troponin T
Troponin
ELC
Myosin binding
protein C
Peng et al. proteomics,
2014
Novel systems biology approach for sarcopenia
• A hallmark of sarcopenia is a progressive
decline in skeletal muscle contractile
function that is, in part, due to alterations in
the structure and function of myofilaments.
• We aim to employ a novel systems biology
approach featuring “top-down” mass
spectrometry-based proteomics and muscle
functional studies to understand age-related
muscle dysfunction in sarcopenia and
identify new targets for prevention and
treatment of this major public health
problem.
What is systems biology? Social network
“Social network” in the cell
What is systems biology?
Albert et al. J. Cell Sci. 2005
Signaling networks in aging
Greer et al. J. Cell Sci. 2008
What is systems biology?
Modified based on https://www.systemsbiology.org/about/what-is-systems-biology/
What is systems biology?
Systems biology, a holistic approach empowered by omics
technologies to deciphering the complexity of biological systems.
Modified based on https://www.systemsbiology.org/about/what-is-systems-biology/
Genomics
Proteomics
Metabolomics
Gene
Protein
Metabolite
"Proteomics includes not only the identification and quantification
of proteins, but also the determinations of their localization,
modifications, interactions, activities, and, ultimately, their
function."
What is proteomics?
Stanley Fields, Science, 2001, 291, 1221
Traditional Biochemistry
Proteomics
Proteomics: the systematic analysis of the entire complement of
proteins expressed by a cell, tissue, or organism.
What’s the significance of proteomics?
Protein: derived from Greek word “proteios” meaning ‘of the first order’ introduced in 1938 by Swedish chemist, JönsJacob Berzelius.
The abundance of a given transcript may not reflect the abundance of
the corresponding protein.
Protein activity depends on post-translational modifications
The function of protein depends on its structure, location, and
interactions with other proteins
Proteins are the most therapeutically relevant molecules in the body.
Genome: static, “blueprint”Proteome: dynamic, “real-life building blocks”
Scott and Mark Kelly
Genome: static, “blueprint”
Proteome: dynamic, “real-life
building blocks”
Why top-down proteomics?
~35,000
genes
~100,000
transcripts
>1,000,000
proteoforms
P
P P
Ac
AcG
G
Me
UU
U
Why top-down mass spectrometry-based proteomics?
Mass spectrometry (MS)
What is mass spectrometry?
PPP young Mid-age old
Simple Definition: A machine used to weigh molecules (A molecular scale).
A mass spectrometer is an instrument that measures the masses of
individual molecules that have been converted to ions, i.e. molecules
that have been electrically charged.
An integrated systems biology approach combining top-down proteomics with functional Analysisto elucidate the molecular mechanism(s) underlying sarcopenia
Gregorich et al. J. Proteome Res. 2016
Why use rodent aging model?
• It is a well established biological model and has been
recommended by the National Institute on Aging (NIA)
for age-related research.
• It has fewer age-related diseases allowing to identify
the molecular signatures of sarcopenia, without the
confounding influence of other age-related pathologies.
• It allows us to assess sarcopenic changes in a
relatively short life span.
Young, 6-month
Mid-age: 24-month
Old: 36-month
(Sarcopenia)
A healthy rodent aging model
(Fischer 344 x Brown
Norway hybrid rat, FBN)
Sarcopenia is associated with loss of skeletal muscle mass and deterioration of muscle quality
6-mo 24-mo 36-mo
*p<0.05 vs. 6-mo. n=12
Rat model of
sarcopenia
Fisher 344xBrown
Norway F1 hybrid
(F344BN)
(gastrocnemius)
http://david-bender.co.uk/Gregorich et al. J. Proteome Res. 2016, 15, 2706
Sarcopenia is associated with loss of skeletal muscle mass and deterioration of muscle quality
*p<0.05 vs. 6-mo. n=12
Rat model of
sarcopenia
Fisher 344xBrown
Norway F1 hybrid
(F344BN)
(gastrocnemius)
http://david-bender.co.uk/
6-
month24-
month
36-
month
Gregorich et al. J. Proteome Res. 2016, 15, 2706
Hematoxylin and eosin stain
RLC Phosphorylation Decreases with Advancing Age
*p<0.05 vs. 6-mo;
**p<0.001 vs. 6-mo
n=6
Zachery Gregorich
Myosin
Regulatory
Light Chain
(RLC)
Gregorich et al. J. Proteome Res.
2016, 15, 2706
RLC Phosphorylation Decreases at Ser14/15 with Age
942 944 946 948 950 952 954 956m/z
RLC
pRLC
ppRLC
Detection of Ser15 as sole site of mono-phosphorylation and Ser14/15 as sites of phosphorylation in bis-phosphorylated RLC suggest ordered mechanism of phosphorylation
Contractile function of skeletal muscle fibers declines with age
*p<0.05 vs. 6-mo
Force-pCa relationships for single
skinned muscle fibers
Maximal isometric force Composite force–velocity (E)
and force-power (F) curves
from gastrocnemius fibers
Gregorich et al. J. Proteome Res. 2016
Conclusion• Sarcopenia is the loss of skeletal muscle mass and
function with aging, highly prevalent in the elderly.
• It is associated with disability, falls, loss of independent
living, representing a major public health problem. But
underlying molecular mechanisms in sarcopenia
remain poorly understood.
• We aim to employ a novel systems biology approach to
identify new molecular determinants of age-related
muscle dysfunction and aid the development of
therapeutic strategies to attenuate or prevent
sarcopenia.
• Our data shows that sarcopenia is associated with
changes in the modifications of key myofilament
regulatory proteins in a rat aging model.
Future Directions
Understand sarcopenia using non-human primate (NHP)
model: Rhesus monkey Collaborators: Ricki Colman, Gary Diffee, Roz Anderson, Rick Moss)
Rhesus monkey and human share strikingly similar
genetic, physiological, and behavior traits, as well as
age-associated diseases.
Source: National Geographic Source: Wikipedia
Rhesus monkey
Future Directions
Young,
6-9 years
Mid-age:
15-16 years
Old: 28-32 years
(Sarcopenia)
Rhesus monkey colony from the Wisconsin National
Primate Research CenterPhoto from Ricki Colman
• Collect skeletal muscle biopsy (~100-150 mg)
• Study sarcopenia-associated changes in myofilament
proteins
Future Directions
Understanding sarcopenia using non-human primate
models (collaborators: Ricki Colman, Gary Diffee, Roz
Anderson, Rick Moss)
Structural and metabolic profiles of skeletal muscle
fibers in young, mid-age and old monkeys.
Young, 6-9 years
Mid-age: 15-16 years
Old: 28-32 years
(Sarcopenia)
Pugh et al. Aging Cell, 2013
Future DirectionsDiscover biomarkers to identify older adults at risk for
developing sarcopenia and develop treatment
Collaborators: Neil Binkley, Bjoern Buehring, Gary Diffee
Group 3. Older adults (65+ year-old)
with sarcopenia*
Group 2. Older adults (65+ year-old)
without sarcopenia*
Sarcopenia definition see
Fielding et al. JAMDA, 2011
Group 1. Young healthy adults
(20-40 year-old)
Future DirectionsDiscover biomarkers to identify older adults at risk for
developing sarcopenia
Collaborators: Neil Binkley, Bjoern Buehring, Gary Diffee
Group 1. Young healthy adults (20-40 year-old)
Group 2. Older adults (65+ year-old) without sarcopenia
Group 3. Older adults (65+ year-old) with sarcopenia
• Collect quadriceps muscle biopsy (~100-150 mg)
• Measure muscle mass and physical function
• Determine age-related changes in single fiber bundles
• Identify age-related changes in skeletal muscle
proteins and correlate them with function
Acknowledgements
Ge Research Group
Ziqing Lin
Tania Guardado
Zachery Gregorich
Yang Hu
Wenxuan Cai
Yutong Jin
Bifan Chen
Trisha Tucholski
Kyle Brown
Zhijie (Abe) Wu
Ya Liu
Andy Alpert
Wisconsin
Partnership
Program
R01 HL096971 (PI)
R01 HL109810 (PI)
R01 GM117058 (MPI)
R01 HL114120 (subproject-PI)
S10 OD018475 (PI)
Collaborators (aging)
Former members
Xintong Dong
Jiang Zhang
Moltu Guy
Cory Nelson
Han Zhang
Xin Chen
Wei Guo
Edith Chang
Santosh Valeja
Ivy Chen
Lynn Peng
Leekyoung Hwang
Serife Ayaz-Guner
Liming Wei
Rick Moss
Gary Diffee
Neil Binkley
Bjoern Buehring
Ricki Colman
Roz Anderson
http://crb.wisc.edu/yinglab/
