Astrocytes and Neurodegeneration in Parkinson's Disease
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Questions and Answers

What is the primary function of oligodendrocytes in the CNS?

  • Producing myelin to insulate axons (correct)
  • Phagocytosing pathogens and dead cells
  • Regulating the blood-brain barrier
  • Producing cerebrospinal fluid

    • Which type of neuroglial cell is involved in the immune defense of the CNS?

  • Microglia (correct)
  • Astrocytes
  • Oligodendrocytes
  • Ependymal cells

    • What role do ependymal cells play in the central nervous system?

  • Phagocytosing debris and pathogens
  • Providing structural support to neurons
  • Insulating neuronal axons
  • Producing cerebrospinal fluid (correct)

    • How can neuroglial changes affect neuronal health?

    <p>They can precede and facilitate neuronal loss.</p> Signup and view all the answers

    Which neuroglial cells are primarily responsible for maintaining brain homeostasis?

    <p>Astrocytes</p> Signup and view all the answers

    What therapeutic significance do neuroglial cells hold in the context of neurodegenerative diseases?

    <p>They may represent a target for slowing disease progression.</p> Signup and view all the answers

    What defines neurological diseases as a failure in homeostasis?

    <p>Inadequate support from neuroglial cells</p> Signup and view all the answers

    Which statement best explains the role of astroglial cells?

    <p>They are involved in regulating blood flow in the brain.</p> Signup and view all the answers

    What is the effect of inhibiting the JAK/STAT3 signaling cascade on huntingtin aggregates?

    <p>Increases huntingtin aggregates</p> Signup and view all the answers

    What role do astrocytes play in the metabolism of dopamine in Parkinson's disease?

    <p>Convert L-DOPA to dopamine</p> Signup and view all the answers

    What does a decreased expression of GFAP in astrocytes indicate in the context of Parkinson's disease?

    <p>Astrogliotic atrophy</p> Signup and view all the answers

    In Alzheimer’s disease, what degenerative change is observed in oligodendrocytes?

    <p>Shrinkage of the white matter</p> Signup and view all the answers

    What is suggested by the presence of activated glial cells in close contact with altered neurons in dementia?

    <p>Astroglial reactivity may be involved in pathology</p> Signup and view all the answers

    How do atrophic astrocytes impact neuronal function?

    <p>Worsen neuronal function</p> Signup and view all the answers

    What consequence does prolonged activation of receptors have on oligodendrocytes in Alzheimer's Disease?

    <p>Cytosolic Ca2+ overload and myelin destruction</p> Signup and view all the answers

    What has been observed about the changes in oligodendroglial precursors in neurodegeneration?

    <p>Degenerative changes affecting remyelinating capacity</p> Signup and view all the answers

    Which of the following statements about oligodendrocyte defects in Alzheimer's Disease is accurate?

    <p>They can serve as early markers of the disease.</p> Signup and view all the answers

    What contributes to early cognitive impairment associated with astrocytic changes?

    <p>Loss and weakening of synapses</p> Signup and view all the answers

    What imaging characteristic is observed in the white matter of patients with advanced Alzheimer's Disease compared to normal aging?

    <p>Atrophy of white matter and enlargement of ventricles</p> Signup and view all the answers

    In 3xTg-AD mice, what was observed at early stages of Alzheimer's Disease?

    <p>Marked morphological atrophy of oligodendrocytes</p> Signup and view all the answers

    What role do NG2 glia play in the later phases of Alzheimer's Disease in relation to senile plaques?

    <p>They infiltrate senile plaques with their processes.</p> Signup and view all the answers

    What is a potential consequence of excitotoxicity mediated by l-glutamate and ATP in Alzheimer's Disease?

    <p>Contributing to oligodendrocyte death</p> Signup and view all the answers

    How do prolonged receptor activations lead to oligodendrocyte death?

    <p>By causing reactive oxygen species production</p> Signup and view all the answers

    What is observed in the white matter lesions in early-stage Alzheimer's Disease?

    <p>They are prominent in periventricular and deep white matter.</p> Signup and view all the answers

    What is the primary marker used to identify reactive astrocytes?

    <p>Glial fibrillary acidic protein (GFAP)</p> Signup and view all the answers

    What type of astrocytes is primarily responsible for forming glial scars after an injury?

    <p>Scar-forming astrocytes</p> Signup and view all the answers

    Which neurological disease is NOT commonly associated with reactive astrocytes?

    <p>Osteoporosis</p> Signup and view all the answers

    How does the deletion of InsP3R type II affect astroglial reactive responses?

    <p>Reduces astroglial reactive response</p> Signup and view all the answers

    Which statement accurately describes the roles of reactive astrocytes?

    <p>Their roles can be both neuroprotective and neurotoxic.</p> Signup and view all the answers

    What effect does preventing glial scar formation have on neuronal cells?

    <p>Leads to neuronal cell damage.</p> Signup and view all the answers

    What is the significance of calcium signaling in astroglial reactivity?

    <p>Calcium release from the ER is critical for astroglial reactivity.</p> Signup and view all the answers

    What changes occur in astrocytes in response to brain or spinal cord injuries?

    <p>They exhibit hypertrophy and morphological changes.</p> Signup and view all the answers

    What primary role do activated microglial cells play in Alzheimer's Disease progression?

    <p>They secrete proinflammatory factors that contribute to neuronal damage.</p> Signup and view all the answers

    In the context of Alzheimer's Disease, what observable phenomenon occurs with microglial function after the formation of senile plaques?

    <p>Microglial phagocytotic function is reduced.</p> Signup and view all the answers

    Which neuroglial change is associated with earlier stages of neurodegenerative diseases?

    <p>Cellular degeneration and asthenic responses.</p> Signup and view all the answers

    What is a significant impact of oligodendroglia alterations in Alzheimer's Disease?

    <p>Pathological remodeling of the connectome leading to cognitive deficiency.</p> Signup and view all the answers

    Which aspect of microglial behavior changes during the progression of Alzheimer's Disease?

    <p>The status and functionality of microglia.</p> Signup and view all the answers

    What is the relationship between β-amyloid and microglial activation in the ageing brain?

    <p>Microglial activation is triggered by β-amyloid.</p> Signup and view all the answers

    What types of changes occur in neuroglia as neurodegenerative diseases advance?

    <p>Reactive phenotypes become more prevalent.</p> Signup and view all the answers

    Which of the following cell types experiences notable degeneration that impacts vulnerability to Alzheimer’s pathology?

    <p>Microglia.</p> Signup and view all the answers

    Study Notes

    JAK/STAT3 Signaling and Huntingtin Aggregates

    • Inhibition of JAK/STAT3 signaling leads to increased huntingtin aggregates, worsening disease progression in neurodegeneration.

    Role of Astrocytes in Parkinson's Disease

    • Astrocytes play a neuroprotective role by metabolizing dopamine and converting L-DOPA to dopamine.
    • They serve as reservoirs for L-DOPA in the striatum, facilitating dopamine transport to neurons.
    • Decreased GFAP expression in astrocytes suggests atrophy and a compromised neuroprotective role in Parkinson’s disease.

    Oligodendrocytes in Neurodegeneration

    • Oligodendrocytes undergo degenerative changes during neurodegenerative processes, like the notable shrinkage of white matter in Alzheimer's disease.
    • Changes in oligodendroglial precursors (NG2 glial cells) may indicate reduced remyelination capacity.

    Historical Perspective on Astroglia in Dementia

    • Alois Alzheimer observed activated glial cells in relation to altered neurons and recognized them within senile plaques.
    • Recently, detailed studies on astroglial pathology in Alzheimer's have garnered attention.

    Impact of Atrophic Astrocytes on Neuronal Function

    • Atrophic astrocytes provide insufficient homeostatic support, exacerbating neuronal dysfunction and cognitive impairment due to synapse loss rather than outright neuronal death.

    Types of Neuroglia

    • Oligodendrocytes: Responsible for myelin production that insulates neuron axons, enhancing signal transmission efficiency.
    • Microglia: The immune cells of the CNS; they phagocytose dead cells and pathogens, maintaining brain health.
    • Ependymal Cells: Line brain ventricles and the spinal canal, producing cerebrospinal fluid for cushioning and protection.

    Neuroglial Changes in Neurodegenerative Diseases

    • Progressive neuronal death is a hallmark of neurodegenerative diseases, but neuroglial changes can precede and facilitate this loss.
    • Malfunctioning astroglial cells disrupt brain homeostasis, potentially contributing to the pathophysiology of neurodegenerative diseases.

    Astrodegenerative Changes and Early Pathology

    • Changes in astrocytes are linked to the early pathology of Alzheimer's, indicating neuroglial reactivity is critical to the disease's progression.

    Reactive Astrocytes

    • Astrocytes become reactive in response to injury or inflammation, classified into hypertrophic and scar-forming types.
    • Reactive astrocytes are involved in various neurological diseases, indicated by elevated GFAP levels and morphological changes.
    • Their roles can be neuroprotective or neurotoxic depending on the injury context, with glial scars potentially preventing damage from invading immune cells.

    Calcium Signaling in Astroglial Reactivity

    • Cytosolic Ca2+ signaling plays a crucial role in astroglial reactivity.
    • Deletion of InsP3R type II significantly reduces reactive responses of astrocytes to lesions.
    • Excessive calcium signaling can trigger oligodendrocyte death and myelin destruction, particularly in Alzheimer's disease.

    Oligodendroglia in Alzheimer's Disease

    • Myelin defects appear before clinical symptoms, serving as early markers for Alzheimer's.
    • Prominent white matter lesions are evident in early-stage Alzheimer's, with notable morphological changes in glial cells.

    Microglial Role in Alzheimer's Disease

    • Microglial changes, both reactive and degenerative, are significant in AD progression.
    • Activated microglia are associated with senile plaques and secrete pro-inflammatory factors contributing to neuronal damage.
    • Loss of microglial function is observed in models of Alzheimer's, reducing beta-amyloid clearance and exacerbating plaque formation.

    Overall Pathological Changes in Neuroglia

    • Neuroglial changes, including cellular degeneration and asthenic responses, occur at early disease stages.
    • As neurodegeneration progresses, neuroglia exhibit reactive phenotypes and exhibit specific morphofunctional changes that vary by region and temporal stages.

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    Week 2(1) - Glial Cells Neurobiology PDF

    Description

    This quiz explores the role of astrocytes in neurodegenerative diseases, particularly Parkinson's disease. It delves into the JAK/STAT3 signaling cascade and examines how astrocytes contribute to dopamine metabolism and impact huntingtin aggregates. Test your knowledge on neuroprotective functions of astrocytes and their implications in neurodegeneration.

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