Final Flashcards
What is an animal model?
A living non-human animal used during the research and investigation of biological process and or human disease
What is the purpose of an animal model?
Gain better understanding cellular and organismal function and disease processes
Why are animal models important?
Help us understand how the body functions and the pathology of diseases
Contributed significantly to human welfare
What are examples of things developed because of animal models?
Polio vaccines (studied transmission of Polio in monkeys, rats and mice)
Antibiotics (researcher infected mice then treated them with penicillin)
What is an effective antibiotic that saves thousands of lives every year?
Penicillin
What are some examples of animal model contributions?
Vaccines
Treatment of Type I diabetes by insulin
Cellular therapies (tissue regeneration using stem cells)
Surgical techniques
What can we learn from a sea slug (aplysia)?
Relatively simple CNS
Small group of neurons respond to individual behavior
Allows researchers to study the biological aspect of learning and memory
How is a fruit fly (drosophila melanogaster) used to study brain disorders?
Many important genes for human development have been characterized by studying the role of similar genes in flies
Relatively simple to manipulate individual genes in the fruit fly
What do researchers assess in drosophila?
Neural degeneration and dysfunction
Why are tiny worms (c elegans) a good model to study brain aging?
C elegans only live about 2 weeks and display aging signs within that time
What are C elegans a transgenic(DNA alteration) model for?
Alzheimer’s disease and other neurodegenerative diseases
What are zebrafish models used for?
Investigate development, genetics, immunity, behavior, physiology, and nutrition
Which animal is the most commonly used organism in research?
Mice (Mus musculus)
Why are mice the most commonly used?
Their genetic, biological and behavioral characteristics are similar to humans and allow researchers to study human diseases
How is learning and memory tested in mice?
The Morris Water Maze
What is the Morris Water Maze?
One of the most commonly used behavioral tests to study spatial learning and memory, which is hippocampus dependent, in mice
What mouse model is used to test mice for AD?
Behavioral test battery
What are transgenic animal models?
Organisms that are genetically modified to have their genome altered
Allows you to knock in or knockout human disease related genes
What are the two types of animal models?
Organism specific (invertebrate, vertebrate)
Disease specific (multiple models per disease)
How are diseases generated in animal models?
Genetic manipulation
Drug-induced
Lesion
What is the knocking in or out of human disease genes called?
Gene editing
What animals are used to study PD?
Cell based assays (yeast)
Transgenic C elegans, Drosophila and fish (zebrafish and medaka fish)
Rodent models
Mice
Non-human primates (monkeys)
Are there laws and regulations for animal use in research and if so what are they?
Yes
Animal Welfare Act
The U.S. Department of Agriculture
Institutional Animal Care and Use Committee (IACUC)
What can we use to study complicated human diseases?
Simple systems
What can we use to track genes?
Florescent protein markers (jellyfish gene)
How can we generate transgenic animals?
By inserting human disease genes into DNA of animals to generate disease model to help understand human diseases
What models have provided important insight into human neurodegenerative diseases?
Transgenic mouse models
What do humans and mice have in common?
Conservation of many genes
Similar brain organization
What are some caveats to animal models?
Not all neuropathological events may develop in animal’s lifespan
Animal proteins may differ from human proteins
Cellular/organismal responses may differ from animals to humans
What is a stem cell?
Can make precise copies of themselves over and over (self-renewal) and can differentiate or mature into different cell types
Stem cells can:
Replicate & differentiate into many cell types
Where are stem cells important?
Developing organisms
Mature organisms
What do stem cells do in developing organisms?
Generate tissue during development
What do stem cells do in mature organisms?
Maintain proper tissue homeostasis or as an internal repair system to replace lost cells or dying cells
Ex. skin, blood cells
Where are embryonic stem cells (ESCs) derived from?
The inner cell mass of blastocysts
Where are multipotent (adult) stem cells located?
Located in different tissues
What are totipotent cells?
Most versatile
Have the potential to give rise to any type of cell, so they can give rise to an entire functional organism
After a few days of embryonic development, they specialize into pluripotent stem cells
What are pluripotent cells?
Can give rise to all cell types in the body
However, cannot give rise to an entire organism
What are embryonic stem cells considered?
Pluripotent stem cells
What are multipotent cells?
Less plastic and more differentiated stem cells
Can still develop into more than one cell type
More limited than pluripotent cells
Give rise to a limited range of cells within a tissue type
What is the order for stem cells?
Totipotent –> Pluripotent –> Multipotent
Pluripotent=
Embryonic stem cells
Multipotent=
Adult stem cells
Where are pluripotent stem cells derived from?
Inner mass of the blastocyst (ESCs)
Why are there ethical implications with collecting ESCs?
Results in the destruction of the blastocyst
How often can embryonic stem cells propagate?
Indefinitely in an undifferentiated state
Can also carry the risk of tumor formation
What do embryonic stem cells have the potential for?
Cell replacement therapies
Tissue engineering
Disease modeling
What kind of cells are adult stem cells?
Multipotent (committed to a particular “fate”)
What quantities are adult stem cells present in?
Present in small quantities
What qualities do adult stem cells have?
Often difficult to isolate/purify
Not as plastic as ESCs (cannot differentiate into as as many different cell types as ESCs)
May contain DNA abnormalities caused by UV light, toxins or errors (mutations during DNA replication for cell division)
What is less common in adult stem cells?
Less likely to form tumors or cause immune rejection
Less moral implications associated with their use
What different tissues can adult stem cells be isolated into?
Muscle
Liver
Bone marrow
Brain tissue
Fat
What is true about neuron replacement in the nervous system?
Relatively quiescent(inactive) and do not participate in tissue renewal or replace neurons lost to injury or disease
What kind differentiation are neural stem cells?
Multipotent
Where are neural stem cells found?
In the adult brain
Can also be derived from embryonic and fetal brain tissue
What can neural stem cells differentiate into?
Astrocytes
Oligodendrocytes
Neurons
How much can neural stem cells isolate?
Cannot isolate in large number
Where does neurogenesis occur in the human adult brain?
In rodents (and possibly humans) adult neurogenesis is in the subventricular zone (SVZ) of the forebrain and the subgranular zone (SGZ) of the dentate gyrus within the hippocampus
However some studies indicate existence of neurogenesis while others don’t
How are Induced Pluripotent Stem Cells (IPSC) created?
By reprogramming a differentiated cell such as a skin cell into an embryonic like stem cell state
Can generate any cell in the organism
Can surpass ethical concerns
What do IPSCs have the potential to do?
Revolutionize biomedicine
Host rejection minimized
Disease modeling potential
Ideal tool for personalized medicine
What has the potential to generate a whole organism?
Totipotent stem cells
How can we treat neurodegenerative diseases with stem cells?
3 main strategies:
-Replace or repair damaged tissue or group of cells that can’t heal itself
-Use stem cells to provide nutrients to sick cells
-Enhance endogenous neurogenesis
What do stem cell therapy for neurodegenerative diseases do?
Designed to target dopamine neurons to help with the creation of new neurons
Clinical trials have been controversial
What does stem cell replacement therapy do?
Replace damaged tissue
What are the caveats (warnings) with neurodegenerative diseases?
Tumor formation
Immune rejection
New transplanted cells may develop the same pathology
What is an alternative strategy for stem cell therapy?
Stem cells can be used to deliver trophic or neuroprotective factors to the brain
What does the FDA say about stem cell therapies?
Be aware of unscrupulous people selling unproven stem cell therapies
What is the most commonly used stem cell-based therapy?
Bone marrow transplantation
What are neurodevelopmental disorders?
A group of conditions that appear during childhood involving some alteration or disruption in the development of the CNS. These disorders are associated with deficits or impairment in the brain function
What are the main types of neurodevelopmental disorders?
Intellectual disability (ID)
Autism spectrum disorder (ASD)
Attention deficit/ hyperactivity disorder (ADHD)
Communication disorders (vision and hearing impairments)
Neurodevelopmental motor disorders (cerebral palsy)
Specific learning disorders (dyslexia)
What is intellectual disability (mental retardation)?
Failure to acquire intellectual abilities across cognitive domains at a normal rate (before 18 years old)
IQ less than 70
Difficulties in adaptive functioning/life skills such as communication, self care, home living and social or interpersonal skills
What are some causes of intellectual disability?
Genetics
Infections
Substances
Metals/chemicals
UV radiation
Lack of nutrition
Oxygen deprivation
Head injury
What are the 4 classes of intellectual disability based on severity?
Mild, moderate, severe and profound
What are the genetic causes of intellectual disability?
Chromosomal abnormalities (down syndrome)
Copy number variations (CNVs)– abnormal number of copies of one or more sections of DNA
Single gene mutations (amino acids repel water which bring folding and a change in function which can be new or a defect
Why does down syndrome occur?
Person has an extra (full or partial) copy of chromosome 21
Most frequent form of intellectual disability
Down syndrome is a consolidation of symptoms
What are the clinical features of down syndrome?
Dysmorphic features (abnormal body structure)
Seizures
Psychomotor slowing
Congenital malformation
What are the physical features of down syndrome?
Low muscle tone
Small stature
Upward slant to the eyes
Single deep crease across the center of the palm
What is true about the severity of down syndrome?
Severity has a variety but they all have the same abnormalities
What are the 3 chromosome abnormalities that cause down syndrome?
Trisomy 21(nondisjunction), translocation and mosaicism
What is trisomy 21(nondisjunction)?
When an error in cell division occurs, called non disjunction and results in an embryo with three copies of chromosomes instead of two
Happens in chromosome 21
What is translocation?
When the total number of chromosomes in the cells remains 46 however an additional full or partial copy of chromosome 21 attaches to another chromosome, usually chromosome 14
What is mosaicism?
When an individual has a mixture of two cell types, some containing the usual 46 chromosome and some containing 47
How is down syndrome diagnosed?
Prenatal screening
Karyotype (a profile of a persons chromosomes)
What are the clinical presentation brain related features of down syndrome?
Morphosyntax, verbal short term memory and explicit long term memory (impaired language and verbal memory abilities)
Seizures
Early onset dementia that resembles Alzheimer’s disease