The role of microglia to regulate Alzheimer's disease pathogenesis
The purpose is to better understand disease mechanisms and to evaluate a new therapeutic principle for Alzheimer's disease (AD). Genetics of sporadic AD shows that activation of microglia, local immune cells in the brain, is important. We are studying disease mechanisms and testing new self-developed compounds related to Triggering receptor expressed on myeloid cells 2 (TREM2), a receptor which is expressed by microglia. Genetic variants of TREM2 with reduced function strongly increases the risk of developing AD.
Distress to the animals will be modest. The transgenic models that we will use have a normal life span and behavior. Aged AD mice can show some cognitive deficits if challenged in difficult mazes. We will reduce distress of drug treatment by handling animals prior to treatment, by involving experienced personal and by using classification schedule to monitor behaviors and pain.
Expected benefits are an increased understanding how TREM2 affects mechanisms of AD. Moreover, data on new self-developed compound, which bind to TREM2, to determine usefulness as AD medicine. Many people suffer from AD, and medicines used today have very limited effects. This makes AD research, including using animal experiments in research, one of the most easy to motivate from a societal perspective.
Number of animals: We will use three transgenic mouse models and two crossbreed models. TgSwe mice (n=300) develop AD-like amyloid deposition and secondary tissue reaction with inflammation in brain. Reporter CX3CR1-GFP mice (n=500) show green fluorescent microglia. TREM2 knockout mice (n=400) do not express TREM2 and will be used to determine whether the effects depend on the TREM2 receptor. We will crossbreed the transgenic models tgSwe x CX3CR1-GFP (n=100) and TREM2 knockout x CX3CR1-GFP (n=100), since this provides experimental advantages when studying microglia. Wild-type mice of C57Bl/6J strain will be used for different experiments, as a control reference mouse and for breeding (n=600).
Replacement is not possible due to the complexity of brain structure and function in a living vertebrate. It is impossible to simulate the interaction of restricted immune cells in the perfectly modulated 3D structure of a living brain. Too many factors of the whole body are working together.
Reduction – we have experience with the models, and we use power analysis to calculate group sizes to make firm conclusions. Animal reduction is reached by using the organotypic hippocampal slice culture (OHSC) model. Thereby, we get 15-20 3D-slices per animal, replacing approximately 3-4 animals. The OHSC model will be used as a screening model for the compounds. However, at the end the compounds have to be tested on living animals to determine pharmacological effects and how the body handles the drug. The same mouse will be used for several blood samplings for pharmacokinetics (= drug turnover in blood with time), and allowed to rest in between according to protocols.
Refinement is done by housing mice in groups in an enriched environment, and by defining schedules with measures monitoring distress/pain and by defining end-points of experiments.
Distress to the animals will be modest. The transgenic models that we will use have a normal life span and behavior. Aged AD mice can show some cognitive deficits if challenged in difficult mazes. We will reduce distress of drug treatment by handling animals prior to treatment, by involving experienced personal and by using classification schedule to monitor behaviors and pain.
Expected benefits are an increased understanding how TREM2 affects mechanisms of AD. Moreover, data on new self-developed compound, which bind to TREM2, to determine usefulness as AD medicine. Many people suffer from AD, and medicines used today have very limited effects. This makes AD research, including using animal experiments in research, one of the most easy to motivate from a societal perspective.
Number of animals: We will use three transgenic mouse models and two crossbreed models. TgSwe mice (n=300) develop AD-like amyloid deposition and secondary tissue reaction with inflammation in brain. Reporter CX3CR1-GFP mice (n=500) show green fluorescent microglia. TREM2 knockout mice (n=400) do not express TREM2 and will be used to determine whether the effects depend on the TREM2 receptor. We will crossbreed the transgenic models tgSwe x CX3CR1-GFP (n=100) and TREM2 knockout x CX3CR1-GFP (n=100), since this provides experimental advantages when studying microglia. Wild-type mice of C57Bl/6J strain will be used for different experiments, as a control reference mouse and for breeding (n=600).
Replacement is not possible due to the complexity of brain structure and function in a living vertebrate. It is impossible to simulate the interaction of restricted immune cells in the perfectly modulated 3D structure of a living brain. Too many factors of the whole body are working together.
Reduction – we have experience with the models, and we use power analysis to calculate group sizes to make firm conclusions. Animal reduction is reached by using the organotypic hippocampal slice culture (OHSC) model. Thereby, we get 15-20 3D-slices per animal, replacing approximately 3-4 animals. The OHSC model will be used as a screening model for the compounds. However, at the end the compounds have to be tested on living animals to determine pharmacological effects and how the body handles the drug. The same mouse will be used for several blood samplings for pharmacokinetics (= drug turnover in blood with time), and allowed to rest in between according to protocols.
Refinement is done by housing mice in groups in an enriched environment, and by defining schedules with measures monitoring distress/pain and by defining end-points of experiments.