Extra cellular matrix protein and proteinaseppt

Extra cellular matrix

1. 04/19/10
EXTRACELLULAR MATRIX
PROTEINS AND
PROTEINASES
By,
Raghu Ambekar
Photonics Research of Bio/nano Environments
Department of Electrical & Computer Engineering
University of Illinois Urbana -Champaign
BioE 506

2. 04/19/10
Outline
Extracellular matrix proteins
Collagen
Classification
Fibril assembly and collagen diseases
Extracellular matrix proteinases
Role of MMP in metastasis
Modification of tumor collagen for therapeutics

3. 04/19/10
Extracellular matrix (ECM)
Surrounds cell
Provides mechanical support
Controls the flow of nutrients
and signals to the cells
Consists of
Fibrous: collagen,
elastin, fibronectin, laminin
Non-fibrous: Proteoglycans
and polysaccharides
http://kentsimmons.uwinnipeg.ca/cm1504

4. 04/19/10
Collagen
Collagen : most abundant protein found in the human
body. About 1/3
rd
of the total proteins.
Found abundantly in tendon, cartilage, bone and skin
Functions:
cell migration
cell adhesion
molecular filtration
tissue repair

5. 04/19/10
Structure of collagen
It has a triple-helix structure containing
three α-polypeptide chains arranged in
right-handed supercoil
Glycine, proline, hydroxyproline
1.5 nm diameter
At least 28 different collagens found
The three α-chains could be same
(collagen II) or different (collagen I)
Collagen molecule

6. 04/19/10
Classification of collagen
No interruptions in triple helix
Regular arrangement results in characteristic “D” period of 67 nm
Diameter : 50-500 nm
Example : Types I, II, III, V, XI
1. Fibril-forming collagens

7. 04/19/10
Classification of collagen
Forms network in basement (Collagen IV) and Descemet’s
membrane (Collagen VIII)
Molecular filtration
Example : Types IV, VIII, X
2. Network-forming collagens

8. 04/19/10
Classification of collagen
Short collagens with interruptions
Linked to collagen II and carries a GAG chain
Found at the surface of fibril-forming collagens
Example : Types IX, XII, XIV
3. Fibril-associated collagens with interrupted triple helices (FACITs)

9. 04/19/10
Classification of collagen
Provides functional integrity by connecting epithelium to
stroma
Example : Type VII
4. Anchoring collagens

10. 04/19/10
Classification of collagen
Form structural links with cells
Example : Type VI
Collagen VI crosslink into tetramers that assemble into long
molecular chains (microfibrils) and have beaded repeat of 105 nm
5. Beaded-filament-forming collagens

11. 04/19/10
Type I Fibril assembly
Chain recognition sequence
Fibril assembly is determined by chain recognition sequence in C-propeptide
Fish scale
Bone osteon
Tendon
Skin

12. 04/19/10
Diseases associated with collagen
Diseases caused by mutations
Subtypes of osteogenesis imperfecta (collagen I)
Ehlers-Danlos syndrome (collagen I and V)
Alport syndrome (collagen IV)
Certain arterial aneurysms (collagen III)
Ullrich muscular dystrophy (collagen VI)
Certain chondrodysplasias (collagen IX and XI)
Kniest dysplasia (collagen II)

13. 04/19/10
Role of MMP in metastasis
Metastasis
Metastasis
Spread of cancer from a primary tumor to distant sites of the body
A defining feature of cancer

14. 04/19/10
Role of MMP in metastasis
Understanding the molecular mechanisms of metastasis is crucial for the
design of therapeutics
Extracellular matrix metalloproteinases (MMP) associated with metastasis
MMPs are capable of digesting ECM and basement membrane under
physiologic conditions
Collagenases degrade fibrillar collagen
Stromelysins degrade proteoglycans and glycoproteins
Gelatinases degrade nonfibrillar and denatured collagens
At tumor sites, experiments have found
Increased number of MMPs
Increased levels of MMPs
Reduced levels of TIMPs (Tissue inhibitors of metalloproteinases)

15. 04/19/10
Role of MMP in metastasis
Major role of MMPs was to facilitate the breakdown of physical barriers,
thus promoting invasion, intravasation, extravasation and migration
MMPs targeted for antimetastasis therapies

16. 04/19/10
Role of MMP in metastasis
Clinical trials of inhibiting MMPs to cure cancer have failed
Metastasis is a complicated process
MMPs contribute to every stage in tumor progression at both
primary and metastatic sites
Specific MMPs play a role in each stage of metastasis
MMP 13, 14 –invasion
MMP 9–angiogenesis
Understand the role of the MMPs in each cancer setting

17. 04/19/10
Modification of collagen for therapeutics
Structure and content of collagen governs the delivery of
therapeutic molecules in tumors
Penetration of therapeutic molecules improved by
developing agents that modify ECM and increase diffusion
Detect tumor collagen noninvasively to quantify collagen
content and estimate drug delivery characteristics

18. 04/19/10
Modification of collagen for therapeutics
Uses Second-harmonic generation (SHG) for imaging only collagen fibers
Conditions :
Non-centrosymmetric (collagen,
microtubules)
Lasers (high intensity)
Advantages :
No staining
3D imaging
No photobleaching
SAMPLE
Red
Wavelength=800 nm
SHG: Blue
Wavelength=400 nm
Collagen stained red and
imaged by fluorescence
microscopy
Collagen imaged by SHG
microscopy

19. 04/19/10
Modification of collagen for therapeutics
SHG intensity collected from live imaging of collagen fibers
provides an good estimate of diffusion coefficient in tumors

20. 04/19/10
Modification of collagen for therapeutics
Chronic relaxin treatment degrades tumor matrix
and improve macromolecular diffusion in tumors
0
th
day 3
rd
day6
th
day 9
th
day 12
th
day
THANK YOU!