Annexe : Neural Crest and Schwann Cell Precursors

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Questions and Answers

What is the name of the structure currently known as the neural crest?

Zwischenstrang (correct)

Neural tube

Neural plate

Somite

Which cells are involved in the spreading of innervation throughout the body?

Schwann cell precursors (correct)

Oligodendrocytes

Astrocytes

Neurons

What is a key role of Schwann cell precursors (SCPs) in the peripheral nervous system?

Secretion of neurotransmitters

Migration along nerve fibers (correct)

Synapse formation

Formation of myelin sheaths

What is NOT a non-canonical role of the peripheral nervous system mentioned?

Control of blood vessel formation (D) Signup and view all the answers

Which of the following is described as a pre-SCP, according to the text?

SOX10+ cells (A) Signup and view all the answers

What does the experiment described in the text with Htpa-Cre/R26RDTA mouse embryos suggest about peripheral nerve growth?

Peripheral nerves are not dependent on Schwann cell precursors for growth (C) Signup and view all the answers

Why are Schwann cell precursors (SCPs) considered multipotent?

They are capable of differentiating into many different cell types (C) Signup and view all the answers

What is the main focus of this article?

The origin and function of Schwann cell precursors (D) Signup and view all the answers

What is the distinguishing feature of SCPs that sets them apart from neural crest cells?

They associate with peripheral nerves. (A) Signup and view all the answers

How does gene expression change during the transition from neural crest cells to SCPs?

The transition involves a gradual change in gene expression, with SCPs gradually acquiring more Schwann cell-specific genes. (C) Signup and view all the answers

What is the significance of the statement "vertebrate development is not synchronized along the anterior-posterior axis" as it relates to neural crest cells?

This suggests that neural crest cells do not always delaminate from the neural tube simultaneously. (E) Signup and view all the answers

What is BFABP and how does it demonstrate the transition to Schwann cells?

BFABP is a gene that appears in nerves as early as E10.5, indicating the early development of Schwann cell characteristics within SCPs. (E) Signup and view all the answers

What markers are mentioned as indicating the premigratory state of a neural crest cell?

No markers are mentioned for the premigratory state. (D) Signup and view all the answers

What is the primary challenge in defining the transition from neural crest cells to SCPs?

The lack of a distinct gene expression change that clearly marks the transition. (C) Signup and view all the answers

What are the possible fates of neural crest cells after they migrate from the dorsal neural tube?

They differentiate into various cell types, including sensory ganglia, skin, and peripheral nerves. (B) Signup and view all the answers

What specific gene becomes apparent in the nerves of the cranial region as early as E10.5?

BFABP (D) Signup and view all the answers

Which of the following processes is not directly involved in the formation of sensory ganglia?

Coalescence of neural crest cells around the dorsal aorta (A) Signup and view all the answers

What is the role of EPHB2 receptor activation by EFNB2 on Schwann cells during nerve regeneration?

Promotes formation of Schwann cell progenitors (D) Signup and view all the answers

What is the role of Sox2 in the process of nerve regeneration?

Sox2 regulates the distribution of N-cadherin, which guides axonal regrowth (B) Signup and view all the answers

Which of the following is NOT a characteristic of BC cells?

Located in the central nervous system (C) Signup and view all the answers

What is the most likely mechanism for the contribution of satellite glial cells (SG cells) to pain development?

SG cells modulate the activity of other neurons involved in pain pathways (C) Signup and view all the answers

What is the significance of TGF-beta-EPHB2 crosstalk in nerve regeneration?

Plays a crucial role in the reprogramming of Schwann cells into progenitors and their subsequent migration (A) Signup and view all the answers

What is a potential limitation of the current research in the field?

Limited understanding of the similarity between fate-specifying mechanisms of neural crest cells and nerve-associated SCPs (B) Signup and view all the answers

Which of the following statements best summarizes the key function of N-cadherin in nerve regeneration?

N-cadherin facilitates the accurate re-growth of axons by guiding their movement (A) Signup and view all the answers

According to the content, during the evolution of animals, what might have been the driving force for the development of neural crest-like cells along the nerves in larger organisms?

The need for cells to migrate outside the central nervous system for various developmental purposes. (D) Signup and view all the answers

What is the significance of the low cell number in the Amphioxus neural tube compared to other animals?

It highlights the ability of Amphioxus cells to compensate with late proliferative activity and multipotency. (B) Signup and view all the answers

Which of the following is NOT a proposed function of pigmentation in animals, according to the text?

Hormone production. (B) Signup and view all the answers

What does the content suggest about the evolution of external photosensory organs?

They likely evolved from cells migrating out of the central nervous system. (A) Signup and view all the answers

Which of the following is NOT mentioned as a potential cell type derived from multipotent progenitors migrating outside the CNS?

Muscle cells. (B) Signup and view all the answers

What is a potential reason for the formation of Schwannomas in patients with neurofibromatosis types I and II?

The tumors are derived from Schwann cell precursors that have been transformed into cancerous cells. (C) Signup and view all the answers

What is the main difference between type I neurofibromas and Schwannomas?

Type I neurofibromas are composed of a wider variety of cell types, including fibroblasts, mast cells, and melanocytes. (A) Signup and view all the answers

What is the main argument presented in the text about the evolution of neural crest cells?

Neural crest cells evolved in a gradual process, with an intermediate multipotent cell type emerging first. (B) Signup and view all the answers

What is the significance of the observed migratory behavior of CNS progenitors in tunicates?

It suggests that the neural crest may have evolved from CNS-derived cells. (B) Signup and view all the answers

What is the key difference between the dissemination strategy of neural crest cells and the migratory behavior of CNS progenitors in tunicates?

Neural crest cells only migrate through specific pathways, whereas CNS progenitors can migrate freely along nerves. (A) Signup and view all the answers

What evolutionary advantage does the repositioning of pigmented photosensory structures from the CNS to the periphery offer?

Improved light detection by placing the photoreceptors in a more exposed position. (D) Signup and view all the answers

How are Hesse ocelli in Amphioxus similar to pigmented cells in tunicates?

Both structures are pigmented and exhibit photosensitivity, suggesting a potential connection to the origin of the neural crest. (B) Signup and view all the answers

Which of the following statements is TRUE regarding CNS-derived cells in tunicates?

They can migrate short distances and generate specialized afferent neurons at the periphery. (A) Signup and view all the answers

What is the significance of melanocytes and melanophores expressing melanopsins and components of the phototransduction cascade?

It suggests a potential connection between melanocytes and classical photoreceptors, strengthening the link to the emergence of the neural crest. (C) Signup and view all the answers

What is the proposed evolutionary scenario suggested by the authors regarding the formation of the proto-neural crest?

The formation of the proto-neural crest was a consequence of intra-CNS pigmented photosensory structures being repositioned to the periphery. (A) Signup and view all the answers

Which of the following statements accurately describes the role of Twist in neural crest development?

Twist is a gene that plays a crucial role in the formation of the neural crest cell lineage. (C) Signup and view all the answers

Which of the following is a plausible explanation for the presence of melanotic schwannoma?

The tumor originates from melanocytes, a cell type with similar origins to SCPs (A) Signup and view all the answers

Which of the following is NOT a potential outcome of the SCP population's multipotency?

Differentiation into astrocytes, forming the central nervous system's support cells (C) Signup and view all the answers

In the context of the research discussed, which would be a suitable method for investigating the potential role of SCPs in the development of parasympathetic ganglia?

All of the above options are suitable methods for investigating the role of SCPs (D) Signup and view all the answers

Based on the provided information, which of the following is a key characteristic of the development of parasympathetic neurons?

The origins of parasympathetic neurons are the same as Schwann Cells, originating from SCPs (A) Signup and view all the answers

The study focusing on the development of parasympathetic ganglia provides evidence for which of the following concepts?

The development of the peripheral nervous system is more complex than previously understood, with SCPs taking a more active role (A) Signup and view all the answers

The study's findings about parasympathetic ganglia development suggests the possibility of applications for?

Targeting SCPs to regenerate peripheral nerve fibers in cases of injury (C) Signup and view all the answers

Given the research on SCPs and their multipotent nature, what could be a further area of investigation?

All of the above are valid areas for further research (D) Signup and view all the answers

The research discussed throws light on which important aspect of developmental biology?

All of the above are important aspects highlighted (D) Signup and view all the answers

Study Notes

Schwann Cell Precursor (SCP) Overview

SCPs are multipotent embryonic progenitors associated with peripheral nerves
They migrate along nerves, reaching various locations in the embryo
SCPs differentiate into diverse cell types: mature Schwann cells, neuroendocrine cells, autonomic neurons, melanocytes, and others
SCPs display similarities to neural crest cells, suggesting a possible evolutionary relationship.
SCPs function extends beyond nerve guidance, playing a role in neurovascular alignment and tissue interactions.

Non-Canonical Functions of SCPs

SCPs aren't strictly required for nerve outgrowth
They proliferate on nerve surfaces, spreading throughout the developing embryo alongside nerves.
Exceptions exist, such as in the facial region, where pre-SCPs (SOX10+ cells) shape nerve pathways.
Early SCP function is linked to nerve-tissue interactions, rather than just neuronal development.
These include neurovascular alignment, guided by CXCL12 and VEGF, molecules secreted by SCPs.

SCP-Dependent Cell Types

SCPs are capable of generating melanocytes (pigment cells), even in locations other than skin.
This suggests that nerve-associated SCPs may be a source for various internal melanocytes and likely play a role in melanoma.
In addition to neurons/melanocytes, SCPs also contribute to parasympathetic and neuroendocrine cell development.
SCPs contribute to the development of adrenal medulla chromaffin cells.
Another potential lineage of SCPs generating cells is mesenchymal cells like dental MSCs, and bone marrow cells.

SCP Plasticity and Evolution

SCPs exhibit high plasticity, differentiating into numerous cell types
This similarity has sparked discussion about the evolutionary relationship between CNS glial and peripheral glial cells.
SCP differentiation can resemble oligodendrocyte development in the central nervous system.
Some hypothesize that myelination ability initially evolved at the periphery, then integrated into the CNS to enhance signal transmission speed.

Neural Crest & Boundary Cap Cells

Boundary cap (BC) stem cells, a subtype of nerve-associated cells, are located at points where peripheral nerves pass the central nervous system border
BC cells have high multipotency, generating various sensory neurons, satellite cells, and specialized glial cells in skin tissues.
These cells have markers (SOX10, FOXD3, etc.) common with peripheral glial cells.
Early steps of SCP development might resemble neural crest cell characteristics and dispersal modes.
The existence of nerve-associated neural crest-like cells that spread via nerves may be an early step in the evolution of neural crest cell properties.

Therapeutic Implications

Neural crest-related diseases (neurofibromatosis, leprosy, specific types of melanomas) are associated with SCPs
Schwannomas (benign tumors derived from Schwann cells) are discussed
SCP plasticity provides opportunities for nerve regeneration and other therapeutic applications

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Description

This quiz explores key concepts related to neural crest cells and Schwann cell precursors in the peripheral nervous system. It covers their roles, characteristics, and developmental processes. Test your understanding of these important structures and their functions in vertebrate development.