8B: Neural Crest Cells

specifically, where are neural crest cells derived from?

brim of neural ectoderm

during?

neurulation

what characteristic of NCCs allows them to migrate freely?

loosely packed/arranged

transitional process NCCs undergo to give rise to different cell types of the body

epithelial-mesenchymal transition

what are the components NCCs form in the face and neck?

facial bones, facial cartilages, facial connective tissues

what cells do NCCs form on the skin?

melanocytes

2 structures that NCCs form in the nervous system

adrenal medulla, sensory ganglia

which specific sensory ganglia?

sympathetic ganglia, parasympathetic ganglia

what are the 2 factors that NCCs depend on?

microenvironmental destination, migratory pathway

what are the 2 major migration pathways for NCCs?

lateral, medial

what is the direction of the lateral migration pathway?

over the somites

which NCCs follow this pathway?

pigment cells/melanocytes

what is the direction of the medial migration pathway?

through anterior region of somites

which NCCs follow this migration pathway?

dorsal root ganglia, sympathetic ganglia

walk me through the life cycle of NCCs

formation of NCCs → migration to target organs → differentiation via cell-to-cell signaling

respectively, what are the general directions of path 1 and path 2?

ventrally via anterior sclerotome, dorsolaterally between epidermis & dermomyotome

most ganglia and facial bones, cartilages, and connective tissues are found in the _________ overlapping domain

cranial

what are the other three remaining domains?

vagal, trunk, lumbosacral

cranial NCCs give rise to?

pharyngeal arches, face, neck

cardiac NCCs (somites 1-3) give rise to?

septum between pulmonary arch & aorta

trunk NCCs (somites 6-tail) give rise to?

sympathetic neurons

which somites support vagal NCCs?

1-7

sacral NCCs (posterior to somite 28) give rise to?

parasympathetic nerves of gut

somites 18-24 give rise to?

adrenal medulla

when there is neurulatioin, there is a concentration of _______

BMPs

what does high level of BMPs induce?

epidermis formation

what does intermediate level of BMPs induce?

NCC formation

what does low level of BMPs induce?

neural ectoderm formation

initial wave of NCC induction: what are the 3 components and what does it induce?

intermediate concentration of BMPs + FGF + WNTs = PAX3 induction

second wave of NCC induction: which transcription factors specify as neural crest?

SNAIL, FOXD3

second wave of NCC induction: which transcription factor promotes NCC migration?

SLUG

where does SLUG originate from?

neuroectoderm

the activation of SLUG is simultaneous with what?

closure of neural tube

FIRST INITIATION OF MIGRATION: which specific BMPs induce RhoB & SLUG?

BMP4, BMP7

what is the second initiation of migration?

loss of n-cadherins

what happens when loss of n-cadherins occurs?

NCCs begin to undergo amoeboid movement

briefly, how do migratory agents know which route to take? what controls the path of NCC movement?

ECM (extracellular matrix) proteins

which specific group of molecules provide contact guidance for the migration pathway of embryonic cells?

SAMs

what does SAM stand for?

substrate adhesion molecule

give me examples of SAMs

fibronectin, laminin, tenascin, collagen, proteoglycans

how are NCCs maintained? what allows their continuous proliferation?

soluble factors are secreted by final destinations (chemotactic)

give an example of a soluble factor

stem cell factors

what determines the final differentiation of NCCs?

cell-signaling factors

give examples of these cell-signaling factors

TGF-β, BMP2 (for lungs, heart and aorta), Endothelin-3, Glucocorticoids, FGF

what specifies the fate of NCCs?

hox genes

what do hox genes do?

specify the A-P (anterior-posterior) axis