Production and Distribution of alpha-synuclein strains (U24 Program)

The U24 Consortium at UTHealth entitled “Production and Distribution of well-characterized polymorphic variants of alpha-synuclein aggregates” is a NIH-funded cooperative agreement aiming to develop, validate and broadly disseminate tools and resources that are highly relevant to research in Alzheimer’s disease (AD) and related dementias.

Rationale

Alzheimer’s disease is the most common form of dementia and contribute to ~60–70% of cases, followed in prevalence by Lewy body dementia (LBD), responsible for 17% of the cases. LBD includes dementia with Lewy bodies (DLB) and Parkinson’s disease dementia (PDD). These diseases are thought to be caused by the accumulation of misfolded protein aggregates in the brain. Although each disease is usually associated with the deposition of a different protein, the aggregates exhibit remarkably similar characteristics. In AD, protein aggregates appear in the form of amyloid plaques and neurofibrillary tangles composed of amyloid-beta (Aβ) and hyperphosphorylated tau, respectively. In DLB and PDD the main component of the aggregates is the α-synuclein (αSyn) protein which accumulates in neurons in the form of Lewy bodies and Lewy neurites. Despite this rather simplistic view, it is common to find a substantial overlap of pathological abnormalities in different patients, leading to the frequent appearance of mixed pathologies, characterized by the presence of multiple protein aggregates in the same brain [6-11]. Indeed, up to 30-40% of AD patients display αSyn Lewy bodies in their brains.

Although, much research has focused on understanding the role of Aβ and Tau aggregates in AD, little is known about the contribution of αSyn in AD and related dementias (ADRD). The structure, size and properties of biologically relevant misfolded protein aggregates are not completely known and the lack of standard materials remains a large problem in the field to compare results between different laboratories. Recently, we implemented an assay termed Seed Amplification Assay (SAA), also referred as PMCA or RT-QUIC, to amplify and detect αSyn aggregates in biological fluids of patients affected by Parkinson’s disease (PD), DLB, PDD, AD and other synucleinopathies.

Goals and Specific Aims

The major goal of this project is to take advantage of the reliability of the αSyn-SAA technology to amplify αSyn polymorphic variants in order to produce and distribute to the scientific community well-characterized αSyn aggregates amplified from patient’s samples. The properties of these aggregates will be comprehensibly studied by biochemical, biophysical, structural and biological methodologies using various in vitro, cellular and animal models. To achieve these goals, we propose the following Specific Aims:

Specific Aim 1. Production of αSyn seeds by αSyn-PMCA/RT-QuIC and analysis of their size, biochemical and biophysical properties.

Specific Aim 2. Elucidate the structural fold at atomic resolution of αSyn aggregates from different synucleinopathies using cryo-electron microscopy (cryo-EM).

Specific Aim 3. Study the biological properties of different polymorphic variants of αSyn aggregates using in vitro and in vivo models.

Specific Aim 4. Produce and distribute to the scientific community well-characterized αSyn aggregates amplified from patients’ samples.