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Principal Investigator: Hanseok Ko
Organization: JOHNS HOPKINS UNIVERSITY
Fiscal Year: 2024
Award: $204,688
Funding agency: National Institute of Neurological Disorders and Stroke
We will evaluate the biological necessity of an intronic enhancer of SNCA and determine its relevance to
Parkinson disease (PD). SNCA is frequently mutated in familial PD; it encodes alpha-synuclein (α-syn), the
primary constituent of Lewy bodies (LB). LB formation/accumulation is a pathological hallmark of PD and is
driven by protein misfolding promoted by SNCA structural mutation, gene amplification, or genetic/environmental
insults that elevate α-syn levels. Noncoding variants predicted to impact SNCA transcriptional regulatory control
are also risk factors for sporadic PD. We recently identified PD-associated variants in SNCA intron 4. These
variants lie within a dopaminergic (DA) neuron open chromatin region (OCR) that we have shown interacts with
the SNCA promoter and is a cis-regulatory enhancer in catecholaminergic neurons. We predict that this
sequence, and the variants therein, impact SNCA transcriptional control and modulate PD risk.
Hypothesis - Deletion of the Snca enhancer in mice will reduce Snca transcription in PD-relevant cells with
potential impact on their viability/distribution, and on motor/non-motor PD phenotypes (Aim 1); deletion will
reduce DA neuron vulnerability to PD-relevant insults and ameliorate the onset and severity of disease (Aim2).
Several highly effective strategies exist to elicit Parkinsonian pathology in mice. Tetracycline (tet)-dependent
expression of PD mutant and wild-type (WT) forms of SNCA in DA neurons result in marked and progressive
loss of ventral midbrain DA neuron populations, consistent with PD pathology. Likewise, intrastriatal injection of
α-syn pre-formed fibrils (PFF) also result in a mouse model that exhibits progressive DA neuronal loss.
Consistent with the known role of Snca levels impacting PD risk and progression, α-syn deficient mice are
protected from PFF-induced neurodegeneration and from tet-dependent expression (via viral vector) of the PD
missense mutant (hA53T) or WT SNCA. α-syn null mice are also protected from the neurotoxic effects of other
PD promoting (and Snca-elevating) insults, like MPTP, 6-OHDA, and LPS. We will test whether cell-dependent
titration of Snca levels, similarly, ameliorates risk and progression in a new mouse model.
We have engineered mouse lines lacking this enhancer (Snca Enhdel) and provide preliminary evidence that
this sequence impacts Snca transcription. Using established techniques, we propose to assay the effect of Snca
Enhdel on prodromal, behavioral, and motor phenotypes (Aim 1a), as well as on PD-relevant neuron
viability/distribution and microglial activation in the midbrain and olfactory bulb (Aim 1b) via
immunohistochemistry and single molecule fluorescence in situ hybridization. Similarly, we will determine
whether Snca Enhdel reduces onset and progression of prodromal/motor/non-motor disease phenotypes (Aim
2a) and impacts DA neuron vulnerability (Aim 2b) when exposed to PD-relevant insults (intrastriatal injection of
SNCA PFF and adenoviral-delivery of SNCA hA53T). We will establish the extent to which modulating Snca
transcription impacts risk of PD relevant pathology in mice, and its potential as a novel therapeutic avenue.
Terms: <6-OHDA><6-hydroxydopamine><Age><Age Months><Assay><Automobile Driving><Behavioral><Bioassay><Biological><Biological Assay><Cell Body><Cells><Chromatin><Cis-Acting Locus><Cis-Acting Sequence><Clinical><DA Neuron><Data><Disease><Disease Progression><Disorder><Dopamine neuron><Dysfunction><Engineering><Enhancers><Equilibrium><Exhibits><Exposure to><FISH Technic><FISH Technique><FISH analysis><FISH assay><Fluorescence In Situ Hybridization><Fluorescent in Situ Hybridization><Functional RNA><Functional disorder><Gene Amplification><Gene Transcription><Genes><Genetic><Genetic Alteration><Genetic Change><Genetic Transcription><Genetic defect><Genetic study><Genotype><Heterozygote><Histologic><Histologically><Homozygote><Human><Immunohistochemistry><Immunohistochemistry Cell/Tissue><Immunohistochemistry Staining Method><Inflammation><Injections><Intervening Sequences><Introns><KO mice><Knock-out Mice><Knockout Mice><Lewy Bodies><Mesencephalon><Mice><Mice Mammals><Mid-brain><Midbrain><Midbrain structure><Modeling><Modern Man><Motor><Murine><Mus><Mutate><Mutation><NAC precursor><Nerve Cells><Nerve Degeneration><Nerve Unit><Neural Cell><Neurocyte><Neuron Degeneration><Neurons><Non-Coding><Non-Coding RNA><Non-translated RNA><Noncoding RNA><Nontranslated RNA><Null Mouse><Olfaction><Onset of illness><Ortholog><Orthologous Gene><Oxidopamine><PARK1 protein><PARK4 protein><Paralysis Agitans><Parkinson><Parkinson Disease><Parkinsonian><Parkinsonian Condition><Parkinsonian Diseases><Parkinsonian Disorders><Parkinsonian Syndrome><Parkinsonism><Pathologic><Pathology><Phenotype><Physiopathology><Population><Primary Parkinsonism><RNA Expression><RNA Splicing><Reporter><Risk><Risk Factors><Risk Reduction><Risk-associated variant><Role><SNCA><SNCA gene><SNCA protein><Severities><Severity of illness><Smell><Smell Perception><Splicing><Symptoms><Techniques><Testing><Tet><Tetanus Helper Peptide><Tetracyclines><Titrations><Transcript><Transcription><Transcription Regulation><Transcriptional Control><Transcriptional Regulation><Transgenic Mice><Untranslated RNA><Variant><Variation><Viral Vector><Work><a-syn><a-synuclein><aberrant protein folding><abnormal protein folding><ages><alpha synuclein><alpha synuclein gene><alphaSP22><asyn><balance><balance function><behavior phenotype><behavioral phenotyping><biologic><clinical relevance><clinically relevant><disease onset><disease phenotype><disease risk><disease severity><disorder onset><disorder risk><dopaminergic neuron><driving><genome mutation><glial activation><glial cell activation><heterozygosity><molecular phenotype><mouse model><murine model><mutant><natural gene amplification><nerve cell death><nerve cell loss><neural degeneration><neurodegeneration><neurodegenerative><neurological degeneration><neuron cell death><neuron cell loss><neuron death><neuron loss><neuronal><neuronal cell death><neuronal cell loss><neuronal death><neuronal degeneration><neuronal loss><neurotoxic><new drug treatments><new drugs><new pharmacological therapeutic><new therapeutics><new therapy><next generation therapeutics><non A-beta component of AD amyloid><non A4 component of amyloid precursor><noncoding><novel><novel drug treatments><novel drugs><novel pharmaco-therapeutic><novel pharmacological therapeutic><novel therapeutics><novel therapy><odor perception><olfactory bulb><olfactory perception><pathologic protein folding><pathophysiology><phenotypic data><pre-formed fibril><promoter><promotor><protein misfolding><reduce risk><reduce risks><reduce that risk><reduce the risk><reduce these risks><reduces risk><reduces the risk><reducing risk><reducing the risk><risk allele><risk gene><risk genotype><risk loci><risk locus><risk variant><risk-reducing><single molecule><social role><sporadic Parkinson's Disease><therapeutic agent development><therapeutic development><α synuclein gene><α-syn><α-synuclein>