Samenvatting - BMS41 - Advanced models of human disease (BMS41) Summary
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Course
BMS41 - Advanced models of human disease (BMS41)
Institution
Radboud Universiteit Nijmegen (RU)
Deze samenvatting bevat alle onderwerpen behandeld tijdens het master vak BMS41- Advanced models of human disease (key criteria to choose a animal model, mouse models, anatomy and physiology of mice, methods to model disease in mice, Cre-loxP system, transgenesis, CRISPR/Cas9, mouse strains, nomenc...
Methods to model disease in mice.......................................................................................................................6
Non-genetic models........................................................................................................................................6
Drosophila models............................................................................................................................9
Anatomy and genetics...........................................................................................................................................9
Methods to model disease in Drosophila...........................................................................................................10
Transgenesis..................................................................................................................................................10
Tissue/time specific genetic manipulation....................................................................................................11
Pros and cons................................................................................................................................................11
Genetic attributes................................................................................................................................................14
Methods to model disease in zebrafish..............................................................................................................15
Transgenesis..................................................................................................................................................15
Loss-of function genetics...............................................................................................................................15
Zebrafish as a suitable model..............................................................................................................................16
Organoid models.............................................................................................................................16
Current approaches.............................................................................................................................................16
What are organoids?...........................................................................................................................................17
The pros and cons of organoids to model renal disorders.................................................................................17
Kidney organoids...........................................................................................................................................17
Animal models for sensory disorders...............................................................................................18
Ocular and retinal characteristics of animal models...........................................................................................18
Human and non-human primates.................................................................................................................18
Cats and dogs................................................................................................................................................19
Usher syndrome..................................................................................................................................................19
Determine pathogenicity of identified genetic variants/genes....................................................................19
Evaluate efficacy of therapeutic strategies...................................................................................................20
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, BMS41 – Advanced Models of Human Disease
Disease models
Model organism: a species that is studied to understand a particular biological phenomenon with the
expectation that discoveries made in the model will provide insight that apply more generally.
Reasons to use (animal) models:
To gain insights into the pathogenesis of the disease phenotype
To identify therapeutic targets and diagnostic markers
Identification of signaling molecules
To test potential treatments
To get a hand on biological samples one cannot get from patients
To minimize environmental impact and control genetic background
Exosomes: small, lipid-bilayer-enclosed vesicles secreted by cells into the extracellular environment. They play
a critical role in cell-to-cell communication by carrying molecular cargo, including proteins, lipids, RNA, and
DNA. As a disease model, exosomes are significant because they reflect the molecular and genetic composition
of their parent cells, offering insights into pathological processes such as cancer progression,
neurodegenerative disorders, and infectious diseases.
The use of animal models is considered when in vitro and computational models cannot capture the necessary
biological complexity to address specific scientific questions. While organoid models provide advanced systems
for studying human diseases by mimicking tissue-level organization, they still lack the full-body physiological
context. Animal models offer a closer approximation to in vivo whole-body physiology, allowing researchers to
study systemic interactions, complex disease dynamics, and therapeutic effects in a more integrated manner.
Key criteria to choose a (animal) model:
Appropriateness as an analog for humans (similarities in anatomy in the context of the disease
modeled)
Transferability of information (similarities in physiology/organ function in the context of the disease
modeled)
Genetic conservation of the target gene(s) to model the disease and of the mutation in case of
inherited diseases
Feasibility to apply techniques of genetic manipulation or to induce certain disease (ease and
adaptability to experimental manipulation)
Ethical and ecological implications
Budget and time
Mouse models
Pros of mice as a model:
Best model for mammalian development
Closely related to humans (mammals)
10-15 offspring per litter and approximately one litter every month
Genome sequenced
Many inbred strains characterized (450 available)
Genetic manipulations well developed
Mice are small, have a short generation time and an accelerated lifespan (one mouse year equals
about 30 human years)
Compensation mechanisms that you will not see in cell models
Cons of mice as a model:
Lab environment vs. natural environment
Animals lack self-consciousness, self-reflection and consideration
Hallmarks of behavioral disorders such as depressed mood, low-self esteem, suicidal tendency are
hardly accessible in mice
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, BMS41 – Advanced Models of Human Disease
Anatomy and physiology
As in humans, there are notable sex differences in mice that affect physiology, behavior, and susceptibility to
diseases. These differences are influenced by genetic, hormonal, and environmental factors.
Embryo development
Mouse embryo development and human embryo development are similar in many respects but also differ in
key aspects. Both species undergo the basic stages of embryogenesis, including fertilization, cleavage,
gastrulation, and organogenesis, but the timing, duration, and specific mechanisms can vary.
Intestine
The anatomy of the mouse intestine shares similarities with that of humans, including the division into small
and large intestines and the presence of key structures such as villi and crypts in the small intestine. These
similarities extend to physiological processes like nutrient absorption and immune function. Additionally, the
gut microbiome in mice, while differing in composition at the species level, resembles the human microbiome
in its functional roles and influence on host health. These parallels make mice a valuable model for studying
intestinal biology and microbiome-related processes.
↪ Omeprazole was tested in a mouse model and showed a reduce in microbial diversity and shifts in microbial
composition
Kidney
The histology of the mouse kidney closely resembles that of the human kidney, with both exhibiting a similar
overall structure and cellular organization. Key similarities include the presence of nephrons composed of
glomeruli, proximal and distal tubules, and collecting ducts. However, there are also very specific differences in
aspects such as nephron number, size, and some molecular pathways, necessitating a critical evaluation of how
findings translate to human biology to ensure accurate interpretation of results.
Human nephrons consist of different regions:
PCT (proximal convoluted tubule): The PCT is the first
segment of the nephron after the glomerulus. It is
responsible for the majority of reabsorption of water,
ions (such as sodium, chloride, and bicarbonate),
glucose, amino acids, and other small molecules from
the filtrate back into the bloodstream.
TAL (thick ascending limb of the loop of Henle): The TAL
is part of the loop of Henle and is responsible for the
active reabsorption of sodium, potassium, and chloride
ions. Unlike other parts of the nephron, it is
impermeable to water, which helps establish the
osmotic gradient necessary for the concentration of
urine.
↪ Furosemide → It inhibits the Na+/K+/2Cl- cotransporter, which reduces sodium, chloride, and
potassium reabsorption, leading to increased urine production.
DCT (distal convoluted tubule): It is involved in the fine-tuning of electrolyte and acid-base balance by
reabsorbing sodium and chloride ions under the regulation of hormones like aldosterone. The DCT
also secretes potassium and hydrogen ions into the filtrate, helping to regulate blood pressure and
maintain pH balance.
↪ Amiloride → It directly inhibits the epithelial sodium channel (ENaC) in the renal tubule, which
reduces sodium reabsorption without causing a significant loss of potassium.
↪ Thiazide → It inhibits the Na+/Cl- cotransporter, reducing sodium and chloride reabsorption, which
increases water excretion.
CCD (collecting duct): The CCD is the final part of the nephron where the reabsorption of water is fine-
tuned, particularly under the influence of antidiuretic hormone (ADH), which increases water
reabsorption in response to dehydration or high blood osmolarity. The CCD also plays a role in the
regulation of sodium, potassium, and pH by secreting or reabsorbing these ions as needed.
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