Langman's Medical Embryology

Developmental Biology

Differentiation Morphogenesis)

Epigenetic landscape (Waddington) ips

Morphogen gradient FGF8 in mouse limb bud Gilbert "Developmental Biology" SHH in chick neural tube

FGF (Fibroblast growth factor) BMP (Bone Morphogenetic Protein) Shh (Sonic Hedgehog) Wnt

Langman's Medical Embryology

http://faculty.virginia.edu/shook/showmovies/index.htm

Gilbert "Developmental Biology"

(384-322 B.C.) "Views of a Fetus in the Womb" 1510-1512

Ernst Haeckel (1834-1919) >

(1869-1941) (1898-1924)

Eric Wiechaus Nobel Prize, 1995 Figure 2. Phenotypes of Mutations affecting segmental pattern. The size and spacing of the pattern deletions in mutant embryos at the end of development allows extrapolation back to requirements for gene activities at blastoderm stage. Segmentation genes can be grouped into threi: classes: mutations in gap genes show large contiguous deletions in the pattern, mutations in pair-rule genes show pattern deletions spaced at double segment intervals, and mutations in segment polarity genes cause pattern deletions in each segment. One example is shown for each class.

"Developmental Biology" FGF10 FGF10 KO Review Development 124, 4867-4878 (1997) Nat Gen. 21, 138- (1999) Dev Dyn 219:121-130 (2000)

Development 133, 1611-2006

u = f(u)+d u

Computational - Mathematical

: ~100 : 1-3

Langman s medical embryology

Epithelium - interface Mesenchyme -inside

0 h 48 h

Dev Dyn 219:121-130 (2000) Development 133, 1611-2006

1.0 unit/ml dispase, 15 min. +FGF Isolate lung epithelium Dissection 50% Matrigel solution in DMEM/F-12 37 o C, 30 min. Gel flattened by the addition of culture medium Culture for 48 hrs Ito & Nogawa, Development 121(4) 1015-22 (1995)

FGF 10 ng/ml FGF1 100 ng/ml FGF1 Development 121(4) 1015-22 (1995)

Control 2 µg/ml collagenase I

FGF Development 124(23) 4867-78 (1997)

Cell 96, 225-233 (1999)

A. predetermined B: dynamically determined

Number of buds 6 5 4 3 2 1 0 Near Far

Mimura et al., Physica A 249, 517- (1998)

FGF = =

FGF c(x, y, t) FGF n(x, y, t) FGF FGF

c(x, y, t + 1) c(x, y, t) = pf(c(x, y, t), n(x, y, t)) + d 1 J(c) n(x, y, t + 1) n(x, y, t) = f(c(x, y, t), n(x, y, t)) + d 2 (c) (n) = n(x + 1, y, t) + n(x 1, y, t) + n(x, y + 1, t) + n(x, y 1, t) 4n(x, y, t) J(c) = (Φ(c c 0 )) Φ(x) = { 0 (x < 0) x (x 0)

f(c, n) = 5cn 1 + 3n, p = 1.0 d 1 = 4.0, d 2 = 1.7 n 0 = 0.5, c 0 = 1.0

Slight protrusion Growth Higher FGF concentration

FGF FGF distribution in numerical simulation Cy3-labeled FGF1 FGF1 immunohistochemistry

Simulation Experiment Low FGF High FGF

FGF 500 ng/ml FGF1 100 ng/ml FGF1

Experiment Simulation FGF-Cy3 beads Control d2=1.7 Collagenase(+) d2=4.0

a b fgf10 shh bmp4 shh, bmp4 Mesenchyme Epithelium fgf10 Expression control Morphological change Dev Cell 18, 8- (2010) Curr Top Dev Biol, 81, 291-301 (2008)

Pericranium

Crouzon syndrome - FGFR GOF mutation Child s Nerv Syst (2000) 16:645 658

J Biomechanics 23(4) 313-321 (1990)

J. Morphol. 185. 285- (1985)

Eden Prof S. Miyajima, FORMA 19, 197-205 (2004)

FGF2, FGF18, FGFR1-4 BMP4, Noggin, TGF beta 1,2,3 Osteopontin, Osterix Twist, Msx2, Alx4, Runx2, Foxc1 Dev Dyn 233:847-852, 2005

PRL 72(15) 2494- (1994)

Localization Differentiation Promote Inhibit Bone Runx2, Osterix - Mesenchyme FGF2, FGF18, BMP4 Noggin, Twist

Stabilizing factors Substrate molecules Localization Differentiation Promote Inhibit Bone Runx2, Osterix - Mesenchyme FGF2, FGF18, BMP4 Noggin, Twist

u: + v: (osteocyte, u>0) mesenchyme, u<0

u = u u 3 + a 1 v + a 0 + u v = a 2 u a 3 v + d v

+ Physica D 34, 115- (1989)

4 days 7 days

3W mouse skull TRAP stain Posterior frontal suture Coronal suture Sagittal suture

a0 u v a 0 = 0.05 t = 0 a 0 = 0.1 a 0 = 0.2 t = 1000

Human Mouse Superficial Deep

Surface Deep FGF2 FGF18

a0 Wt FGFR2c GOF Het

Human lambda suture

...

u = u u 3 + a 1 v + a 0 + h(t) u v = ɛ( u v)+h(t)δ v h(t): Exponential decreasing function with t

Koch Time Spatial scale

Summary II 2 FGF

Coda.

J. Murray "Mathematical Biology"

Well, the stripes are easy but what about the horse part? F. Crick, 1972

Horse part

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