Neural Crest Cells

Cranial Neural Crest Cells

Generate the craniofacial mesenchyme- cartilage, bone, cranial neurons, glia, pigment, connective tissue

Cardiac Neural Crest Cells

Connective tissue of the heart and larger arteries. Populate posterior pharyngeal arches (3-6) and will generate melanocytes, neurons, cartilage, and connective tissue

Trunk neural crest cells

Migrate through two major pathways

a) through somites to generate dorsal root ganglia and sympathetic ganglia

b) dorsolaterally to populate the dermis as melanocytes

dorsal root ganglia

Sensory spinal ganglia derived from the trunk neural crest that migrate along the ventral pathway and stay in the sclerotome

sympathetic ganglia

ganglia of the aorta generated by trunk NCCs

melanocytes

pigment cells of the dermis/epidermis

Vagal and sacral NCCs

The parasympathetic ganglia of the gut (enteric ganglia)

BMPs, Wnts and to a lesser extent Fgfs

The same signals that specify epidermal vs. neurectoderm fate control the neural crest and placode decision

neural plate border specifiers

A set of transcription factors induced by the neural plate inductive signals, that collectively confer upon the border region the ability to form neural crest and dorsal neural tube cell types.

neural crest specifiers

A set of transcription factors induced by the neural plate border-specifying transcription factors, that specify the cells that are to become the neural crest.

Pax3/7 and Dxl 5/6

neural plate border specifiers TFs

Foxd3, Sox9, Snail and later Sox10

neural crest specifiers TFs

Foxd3

regulates expression of the cell surface proteins that direct migration and may be the principal TF that promotes NC identity.

It is sufficient to transform neural plate cells to NC identity

Sox10

one of the most critical regulators of NC specification

1. Maintains stem cell like quality

2. Necessary for delamination and EMT

3. Regulates expression of NC effector genes – those that promote change in cell shape and migration

4. In combination with paracrine pathways and other TFs it promotes distinct NC cell lineages

Epidermis

E-Cadherin

Neuroectoderm

N-Cadherin

Premigratory NCCs

Cadherin-6B

Snail 2

Wnt and BMP signaling from the ectoderm activates core EMT regulatory factors in its lateral-most edges

Sox2

expression becomes fixed in the neural plate by default.

Snail2 and Sox2

cross-repress one another and draw the sharp boundary between neural plate and neural crest

are necessary and sufficient for EMT in neuroepithelial cells

Rho GTPases

promoting actin remodeling that drives apical constriction and delamination

Contact Inhibition

The mechanism whereby cells are prohibited from forming locomotory pseudopodia along contact surfaces with other cells. These interactions with the cell membranes of other cells prevent “backward” migration over other cells and result in “forward” migration of the leading edge of cells

Wnt planar cell polarity pathway

leads to activiation of RhoA

RhoA

promotes disassembly of actin cytoskeleton

Rac

Rho Family Member, promotes lamellipodia formation and migration

complement 3a

mediates contact inhibition (protein)

autonomic neurons

unconscious regulation of specific body functions, like heart rate, digestion, respiration etc.

ephrins, slit, semaphorin 3F

Chemorepellents

semaphorin-3F and ephrins

NCCs are repelled from the posterior compartment of the sclerotome because it also expresses ____ and ____

MITF

A transcription factor necessary for melanoblast specification and pigment production.

Foxd3

represses MITF