Neuro - Repair and Regeneration 2

Which type of cells are responsible for remyelination of damaged neurons in the central nervous system?

Oligodendrocytes

What is the role of chondroitin sulfate proteoglycans (CSPGs) in axonal regeneration?

They inhibit axonal growth

Which of the following is a common target for therapeutic intervention in neurorepair?

Glial cells

What is the main purpose of neurotrophic factors in neurorepair?

To stimulate neuronal survival and regeneration

Which of the following is a common mechanism of axonal regeneration in the peripheral nervous system?

Myelin degradation

What is the role of extracellular matrix (ECM) molecules in neurorepair?

They promote axonal growth

What is the function of neural stem cells in neurorepair?

To form new neurons

What is the role of glial scar formation in neurorepair?

To prevent further tissue damage

Which of the following is a common approach to enhance neurorepair?

Transplanting stem cells

What would you expect to happen if you inserted a section of peripheral nerve into a lesioned central nerve tract: regeneration or suppressed regeneration?

regeneration

True or False: Regenerated CNS axons can not form fully functioning synapses

false

What neuronal element inhibits regeneration of central axons?

myelin

Which of the following proteins does myelin contain, becoming exposed when myelin breaks down?

Nogo-A

Oligodendrocyte-myelin glycoprotein (OMgp)

Myelin-associated glycoprotein (MAG)

Chondroitin sulphate proteoglycans (CSPG) are major components of the glial scar and are thought to suppress axon regeneration through interaction with the receptor tyrosine phosphatase PTP-sigma, which activates intracellular mediators such as ____ and _____

Rho; ROCK

ROCK; Rho

Nogo-A, OMgp, and MAG are found on ______

oligodendrocytes

Nogo-A, OMgp, and MAG can bind to the receptor protein NogoR, which can associate with the neurotrophin receptor p75, and an immunoglobulin-like receptor protein PirB. Does inactivation of PirB results in enhancement or inhibition of corticospinal axon regeneration?

enhancement

The extracellular space contains two obstacles to nerve growth: ____ molecules, which have a backbone and many side branches that block the way; and ____ proteins that actively stop growing nerve fibres.

CSPG; Nogo

The bacterial enzyme chondroitinase ABC can prune the side chains of ____, clearing the way for growing nerve fibres. It has also been shown that Nogo can be blocked by specific _____.

CSPG; antibodies

True or False: The growth potential of central axons decreases with age

true

True or False: If the peripheral branch of an axon is sectioned (lesioned) before the central branch is damaged, the central branch will grow beyond its lesion site

true

The impact of a peripheral “conditioning lesion” can be mimicked by elevating levels of ____ or the growth-associated protein ____ in the peripheral branch

cAMP; GAP-43

Suppressor of cytokine signaling 3 (SOCS3) blocks the ability of _____ to bind its receptor GP130 and thus blocks it from promoting regeneration

CNTF

ciliary neurotrophic factor

Would you expect regeneration in a SOCS3 knockout mouse? Yes or no

yes

Phosphatase and tensin homolog (PTEN) blocks signaling through _______

mammalian target of rapamycin

mTOR

Would you expect regeneration to occur in a mouse with a functional gene encoding PTEN? Yes or no

no

True or False: Severed corticospinal axons can re-establish connections with motor neurons by sprouting axon collaterals that innervate propriospinal interneurons whose axons bypass the lesion and contact motor neurons located caudal to the lesion site

true

True or False: Function can be recovered after spinal cord injury through reorganization of spinal circuits

true

The cortex projects to the spinal cord via the corticospinal tract (CST) and also projects to the ___ in the brainstem

ventral gigantocellular nuclei

vGi

Neuromodulation and rehabilitation training coax the cortex into re-establishing connectivity with the spinal cord by enhancing the formation of circuits between ___ and ____, as well as vGi and spinal cord below the level of injury

cortex; vGi

vGi; cortex

True or False: New neurons being formed, called neurogenesis, does NOT take place in adults

false

True or False: Neurons born in the germinal zone of the dentate gyrus in adult rodents are integrated into hippocampal circuits

true

Adult neurogenesis in the dentate gyrus of the hippocampus undergoes ___ developmental stages

five

5

A multipotent neural stem cell gives rise to an intermediate precursor ‘transit amplifying cell’ that divides _______

asymmetrically

In the differentiation phase, postmitotic neuroblasts differentiate into ______ (2 words)

immature neurons

In the synaptic integration phase, new granule neurons receive inputs from the ____ and send outputs to the CA3 and hilus regions.

entorhinal cortex

True or False: In a Parkinsons patient, direct injection of embryonic dopaminergic neurons into the putamen will reactivate the globus pallidus output pathways

true

True or False: Induced pluripotent stem cells can be reprogrammed to generate precursors of many neuronal and glial types; precursors can then be transplanted into the brain or spinal cord, where cells complete their differentiation and integrate into functional circuits

true

Restoration of myelination in the CNS can be done via transplanted _____ stem cells

oligodendrocyte