Neurodegenerative Diseases Overview
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Neurodegenerative Diseases Overview

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Questions and Answers

What is a primary characteristic of neurodegenerative diseases?

  • They lead to increased neuronal regeneration.
  • They result in permanent recovery of cognitive functions.
  • They are primarily caused by infectious agents.
  • They involve the progressive degeneration of neurons. (correct)

    • Which of the following best describes the impact of amyloid plaques in Alzheimer's disease?

  • They prevent neuronal death.
  • They enhance neuronal communication.
  • They disrupt neuronal communication and trigger inflammatory responses. (correct)
  • They facilitate the regeneration of axons.

    • What role do chaperone proteins play in neurodegenerative diseases?

  • They promote the formation of amyloid aggregates.
  • They directly repair damaged neurons.
  • They assist in properly folding misfolded proteins. (correct)
  • They inhibit ubiquitination processes.

    • In the context of neurodegenerative diseases, what does ubiquitination primarily involve?

    <p>Tagging of defective proteins for degradation.</p> Signup and view all the answers

    Which of the following diseases is NOT classified as a common neurodegenerative disease?

    <p>Multiple sclerosis</p> Signup and view all the answers

    What is a major consequence of the limited neuronal regeneration in adult CNS?

    <p>Permanent loss of cognitive and motor functions.</p> Signup and view all the answers

    What initial step is often associated with many neurodegenerative diseases?

    <p>Protein misfolding and aggregation.</p> Signup and view all the answers

    What limitation is associated with pharmacological intervention in neurodegenerative diseases?

    <p>The lack of replacement for dead neurons.</p> Signup and view all the answers

    What is a direct consequence of ischemia in the brain?

    <p>Increased depolarization of neurons</p> Signup and view all the answers

    Which of the following correctly describes amyloid plaques in Alzheimer's disease?

    <p>Deposits of beta-amyloid proteins</p> Signup and view all the answers

    How do cholinesterase inhibitors assist in the treatment of Alzheimer's disease?

    <p>They enhance the effects of acetylcholine</p> Signup and view all the answers

    What role does NMDA receptor activity play in neuronal death during ischemic events?

    <p>It promotes excessive calcium accumulation</p> Signup and view all the answers

    Which genetic mutation is associated with an increased risk of developing Alzheimer's disease?

    <p>ApoE4 lipoprotein gene mutation</p> Signup and view all the answers

    What adverse effect may occur with Memantine usage in Alzheimer's treatment?

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

    What is the primary mechanism by which excitotoxicity contributes to neuronal death?

    <p>Overactivation of NMDA receptors</p> Signup and view all the answers

    What is the significance of losing cholinergic neurons in Alzheimer's disease?

    <p>It contributes to learning and memory deficits</p> Signup and view all the answers

    What role do reactive oxygen species (ROS) play in neurodegenerative diseases?

    <p>They are a byproduct of ATP production that can cause oxidative stress.</p> Signup and view all the answers

    What is the primary characteristic of necrosis in neuronal death?

    <p>It is an uncontrolled form of cell death resulting from acute injury.</p> Signup and view all the answers

    Which of the following is NOT a characteristic of apoptosis?

    <p>It leads to a local inflammatory response.</p> Signup and view all the answers

    How does calcium overload contribute to excitotoxicity in neurons?

    <p>It disrupts cellular signaling, leading to cell death.</p> Signup and view all the answers

    Which of the following factors is associated with the pathogenesis of Alzheimer's disease?

    <p>Impaired mitochondrial energy metabolism leading to apoptosis.</p> Signup and view all the answers

    Which mechanism of neurodegeneration is characterized by inflammation due to cell injury?

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

    What is a common consequence of oxidative stress in neural cells?

    <p>Damage to cellular components leading to cell death.</p> Signup and view all the answers

    Which class of drugs is often explored in treatment for neurodegenerative diseases?

    <p>Antioxidants targeting increased ROS levels.</p> Signup and view all the answers

    Study Notes

    Neurodegenerative Diseases

    • Characterized by progressive neuron degeneration in the CNS
    • Leads to cognitive and motor function loss, disability, and death
    • Common diseases: Alzheimer's, Parkinson's, ALS, Huntington's
    • Dead neurons are not replaced in the adult CNS
    • Limited neuronal regeneration limits pharmacological interventions

    Protein Misfolding and Aggregation

    • Initial step in many neurodegenerative diseases
    • Aggregates form amyloid deposits with age
    • Amyloid plaques impede neuronal communication and trigger inflammation
    • Contribute to neurodegeneration (e.g., Alzheimer's disease)

    Protective Mechanisms Against Misfolded Proteins

    • Chaperone Proteins:
      • Bind to misfolded proteins
      • Assist in correct folding, preventing toxic aggregates
    • Ubiquitination:
      • Tags defective or damaged proteins with ubiquitin
      • Signals proteins for destruction within the proteasome
      • Maintains cellular health

    Mechanisms of Neuronal Death

    • Ischemic Brain Damage:
      • Interrupted blood supply initiates neuronal damage
      • Depolarizes neurons and releases glutamate
      • Excess calcium accumulation due to glutamate on NMDA receptors
      • Increased nitric oxide production

    Mechanisms of Neuronal Death: Alzheimer's Disease

    • Pathogenesis:
      • Common age-related dementia
    • Main Pathological Features:
      • Amyloid Plaques: Beta-amyloid protein deposits
      • Neurofibrillary Tangles: Tau protein aggregates
      • Neuron Loss
    • Genetic Mutations:
      • ApoE4 mutations increase AD risk
      • Tau protein mutations contribute to degeneration
      • Loss of cholinergic neurons causes learning and memory deficits

    Mechanisms of Neuronal Death: Necrosis

    • Uncontrolled cell death due to injury, infection, or inadequate blood supply
    • Triggers inflammation
    • Occurs in neurodegenerative disorders

    Mechanisms of Neuronal Death: Excitotoxicity

    • Glutamate and calcium are key chemical signals
    • Excess glutamate is highly toxic to neurons
    • Calcium overload is a major factor in excitotoxicity and neuronal death

    Mechanisms of Neuronal Death: Apoptosis

    • Programmed cell death that is controlled and safe
    • Cells shrink and are safely removed without inflammation
    • Essential for development and tissue maintenance
    • Mitochondrial dysfunction is a major factor in many neurodegenerative disorders

    Mechanisms of Neuronal Death: Oxidative Stress

    • Brain requires high energy, producing ATP
    • During ATP production, oxygen is reduced to water, generating Reactive Oxygen Species (ROS)
    • Oxidative stress occurs when ROS production overwhelms antioxidant defense mechanisms

    Drugs for Neurodegenerative Diseases

    • Cholinesterase inhibitors (Donezepil, Rivastigmine), and Memantine are approved for treating AD
    • Cholinesterase inhibitors enhance acetylcholine levels by inhibiting its breakdown
    • Memantine:
      • Weak NMDA receptor antagonist, potentially inhibiting excitotoxicity
      • Modest cognitive improvement in moderate or severe AD
      • Long half-life
      • Adverse Drug Reactions: Headache, dizziness, drowsiness, constipation, shortness of breath, and hypertension
    • Limitations:
      • Currently, no drugs specifically target protein misfolding and aggregation, the root cause of many neurodegenerative diseases
      • Focus on symptom management

    Future Directions

    • Research is ongoing to develop new drugs and therapies that address:
      • Protein misfolding and aggregation
      • Neuroinflammation
      • Neuroprotective strategies
      • Gene therapy
      • Stem cell therapy
      • Lifestyle modifications and personalized medicine
    • Aim: To slow or prevent the progression of these devastating diseases.

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    Lesson 16: Neurodegenerative Diseases (CEU, 2024/25) PDF

    Description

    This quiz delves into the causes and effects of neurodegenerative diseases, such as Alzheimer's and Parkinson's, focusing on the role of protein misfolding and aggregation. Explore the protective mechanisms that cells employ to combat these issues and understand their significance in neuronal health.

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