AAV A53T Alpha-Synuclein Mouse Model of Parkinson's Disease

Q: Can you quantitatively measure the dopaminergic denervation in this model?

Yes. We use our proprietary PERMITS™ software to derive quantitative measures from digitized tissue sections. To assess dopaminergic terminal loss in the striatum, we immunostain the tissue sections for tyrosine hydroxylase (TH) and then quantify the TH-positive processes.

Q: What is the "cylinder test"?

The cylinder test is a technique used to evaluate spontaneous motor behavior in rodents. During this test, the percentage of use of each forelimb is assessed while the animal engages in vertical exploratory behaviors or makes contact with the cylinder walls. This behavioral test serves as a measure of forelimb preference or asymmetry, and can provide insights into motor deficits, recovery, or asymmetrical impairments following unilateral dopaminergic denervation.

Q: How do you quantify "activated" microglia in the AAV-Syn model?

Our team at Biospective has developed advanced computer vision & machine learning algorithms to quantify activated microglia based on their morphology on immunohistochemistry and multiplex immunofluorescence images. You can learn more in our Presentation - Microglial Activation in an α-Synuclein Mouse Model of Parkinson's Disease.

Q: What is an "adeno-associated virus" (AAV)?

Recombinant adeno-associated viruses (rAAVs) are gene delivery tools that are widely used for research and clinical applications. AAV is a single-strand DNA virus carrying a 4.8kb base DNA molecule. For gene therapy or somatic transgenesis, the viral DNA is replaced with engineered DNA containing the gene of interest (GOI).

AAV Synuclein (AAV-Syn) Model Overview

For this Parkinson's disease model, we perform unilateral stereotaxic inoculation of AAVs overexpressing A53T mutant human alpha-synuclein into the substantia nigra of C57BL/6 mice at ~3 months-of-age. This mouse model reproduces several key features of human Parkinson's disease, including:

A high degree of loss of dopaminergic neurons in the substantia nigra pars compacta
Dopaminergic denervation of the ipsilateral striatum
Aggregates of phosphorylated alpha-synuclein in cell bodies and neurites
Activated microglia (Read More in our Presentation - Microglial Activation in an α-Synuclein Mouse Model of Parkinson's Disease)
Reactive astrocytes
Motor dysfunction

AAV-Syn Model Generation

A general schema for the model generation is:

A stereotaxic surgery setup with a rodent

For this specific model, we use C57BL/6 mice at ~12 weeks-of-age. We then perform stereotaxic injection of AAV vectors into the vicinity of the substantia nigra. We use digital stereotaxic devices with automated microinjectors for high accuracy & precision.

Studies using this model can be rapidly initiated. The in vivo phase of the study typically lasts ~10-12 weeks. As such, generation of readouts can be provided in a relatively short time frame, especially compared to conventional alpha-synuclein transgenic models of Parkinson's disease.

Our Validated Measures

Rotarod test
Cylinder test
Tail suspension swing test
Hindlimb clasping test
IHC & multiplex immunofluorescence

Microscopy Images

The Interactive Image Viewer below allows you to explore an entire Multiplex Immunofluorescence tissue section from our AAV-Syn mouse model.

You can pan around the image using the left mouse button. You can zoom in and out using the mouse/trackpad (up/down) or the + and - buttons in the upper left corner. You can toggle (on/off), change color, and adjust image settings for the channels and segmentations in the Control Panel in the upper right corner. You can change tissue sections using the Section Slider in the Control Panel.

Multiplex immunofluorescence tissue section that demonstrates phosphorylated α-synuclein aggregates, activated microglia, and dopaminergic neuron loss ipsilateral to AAV-Syn injection into the substantia nigra (left hemisphere) in a C57BL/6 mouse.