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Zelluläre Mechanotransduktion

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Was ist sie und wo tritt sie auf?

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Zelluläre Mechanotransduktion

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Wolff‘s Law, 1892; Bone growth Bone and Muscle

Arteriosclerosis

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Zelluläre Mechanotransduktion

Was ist der molekulare Ursprungder Mechanotransduktion?

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Stimulus

Receptor

Signaltransduction-Cascade

Activation of Transcriptionproteins

Genexpression

Proteinsynthesis

Zelle

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Mechanotransduktion: Reduktionistischer Ansatz

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Geiger, B. et al., Annu Rev Cell Dev Biol.,19:677, 2003

ExtracellularMatrix (black)

Adhesion-Receptors

Focal Adhesion-Complex (brown)

Cytoskeleton (green)

Nucleus (blue)

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Zelluläre Mechanotransduktion

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Mitra, S.K.; Nat Rev Mol Cell Biol, 2005, 6

ECM-Integrin-FAC Verbindung

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Nucleus

Zelluläre Kraftübertragung

Extracellular Matrix (Fibronectin, Vitronectin, Laminin, Collagen etc.)

Nucleus

F9Wt F9Wt

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Goldmann and Ingber, BBRC 290:749, 2002

relative speedExtracellular Matrix Proteins (based on Fibronectin)Fibronectin 100Vitronectin 79Laminin 25

Bovine Serum Albumine (BSA) 5

Migration of F9 Cells

Influence of Different Extracellular Matrix Proteins

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Fibronectin

Bovine SerumAlbumine (BSA)

Cell Spreading

Influence of Fibronectin Concentration

5 μg/ml

20 μg/ml

Goldmann, Cell Biol. Int. 26:279, 2002

F9Wt

F9Wt

t=0‘

F9Wt

F9Wt

t=240‘

F9Wt

t=240‘

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11

Pro

gram

med

Cel

l Dea

th

Goldmann, Chen, Ingber et al. Oxford University Press, 2000Chen, Huang, Ingber Science, 276:1425, 1997

Endothelial Cells on5μg/ml Fibronectin

Influence of Adhesion Area on Cell Behavior

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α β

Nucleus

IntegrinExtracellular Matrix (Fibronectin, Vitronectin, Laminin, Collagen etc.)

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Zelluläre Mechanotransduktion

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Xiong, Arnaout et al. Science 296:151, 2002

Integrin-Binding to the Extrazellular Matrix

RGD-Region

Consisting of3 Amino Acids:(Arginine, Glycine,Aspartate)

αvβ3 Integrin

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α β

Focal Adhesion Complex (FAC)Nucleus

IntegrinExtracellular Matrix (Fibronectin, Vitronectin, Laminin, Collagen etc.)

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Zelluläre Mechanotransduktion

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α β

Nucleus

Integrin

Actinα β

Actin (green)FAC (brown)

Courtesy of Dr. AltankovFocal Adhesion Complex (FAC)

Extracellular Matrix (Fibronectin, Vitronectin, Laminin, Collagen etc.)

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Zelluläre Mechanotransduktion

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α β

Nucleus

IntegrinCross-linker

Actin

α β

Extracellular Matrix (Fibronectin, Vitronectin, Laminin, Collagen etc.)

Focal Adhesion Complex (FAC)

Goldmann, Cell Biol. Int. 26:313, 2002

MEF

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Zelluläre Mechanotransduktion

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C

A B

D

Magnetic Twisting Zytometrie

MEFs

Fabry et al., J. Magnetism Magnetic Materials 194:120-125, 1999 17

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α β

Nucleus

Integrin

CREB

Cross-linker

α β

Magnetic twisting

bead

10 μm

Extracellular Matrix (Fibronectin, Vitronectin, Laminin, Collagen etc.)

Focal Adhesion Complex0

50

100

150

CR

EB P

hosp

hory

latio

n

(%

ove

r con

trol

)

Bead

Twist

No Twist

RGD AcLDL

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Zelluläre Mechanotransduktion

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α β

Nucleus

Integrin

CREB

VinculinCross-linkerExtracellular Matrix (Fibronectin, Vitronectin, Laminin, Collagen etc.)

Focal Adhesion Complex

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Zelluläre Mechanotransduktion

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24 h adhesion on collagenMEFwt MEFvin-/-A

B DC

0

5

10

15

20

25

MEFwt MEFvin-/-

Foca

ladh

esio

n-s

ize

[µm

2 ]

0123456789

10

MEFwt MEFvin-/-

Foca

ladh

esio

nle

ngth

[µm

]

E

0100020003000400050006000700080009000

MEFwt MEFvin-/-

Spre

adin

gar

ea[µ

m2 ]

*

05

1015

20253035

MEFwt MEFvin-/-

Con

tact

s/ce

ll

Zell Adhäsion an Collagen, after 24h

20 μm

MEFwt MEFvin-/-

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Magnetic Tweezers

20 µm

5 µm

REM

Bright Field

Principle

d = a(t/t0)b

MEFwt 1 nN Force

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300u

m

Fluorescently marked beads Cell

Tractions and Strain Energy

Experimential Setup

4.7 % Polyacrylamide gel; ~3 kPa

Matrix Deformation

Mierke, Fabry, Goldmann et al. Biophys. J, 94:661, 2008

MEF Wildtype Cell

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U = Strain EnergyT = Forcesu = Matrix Deformationr = each point

U = (1/2) ∫ T ( r ) ⋅ u ( r )dxdy

Calculation of Strain Energy

Butler, Fabry et al. Am J Physiol Cell Physiol. 282:C595 23

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10µm

Matrix Displacement Forces (T)

Mierke, Fabry, Goldmann et al. Biophys. J, 94:661, 2008

Tractions and Strain Energy

MEF Wildtype Cells

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A)

B)

Kontraktile Kräfte auf MEF Zellen

Klemm et al. BBRC 379:799, 2009Mierke, Fabry, Goldmann et al. Biophys. J, 94:661, 2008

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Spontaneous Bead Bewegung

Focal adhesioncomplex

Integrin

Stressfibers

Fibronectin

The evolution of the mean squared bead displacement (MSD) over time, t can here be described by an apparent diffusivity, D and an index of persistence, β according to MSD = D·(t/t0)β + c

Raupach, Fabry et al. Phys. Rev. E Stat. Nonlin. Soft Matter Phys. 76:011918, 2007 26

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Vinculin Expression reguliertCytoskeletal Dynamics and Fluidity

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