Periodic Reporting for period 1 - Alpha-Synuclein (Blocking the prion-like disease propagation in Parkinson’s disease and related disorders – model development and identification of cell-autonomous and cell non-autonomous factors.)
Période du rapport: 2019-09-01 au 2021-08-31
PROBLEM STATEMENT
Parkinson disease (PD) is the second most common neurodegenerative disease in populations aged 60 years or above. Current estimates indicate that the clinically diagnosed PD affects more than 6 million people worldwide, and presents a significant socio-economic burden. While the underlying cause of PD remains a matter of rigorous scientific inquiry, examination of (post-mortem, deceased) patient brains shows that there is a profound loss of dopamine producing neurons in several brain regions, particularly affecting a region in midbrain called the substantia nigra (pars compacta). Based on these observations, the clinical interventions are aimed at symptomatic relief, with dopamine replacement (through L-dopa treatment) as the gold-standard approach. However, the disease is progressive and eventually current clinical therapies lose efficacy in majority of the patients after 5-10 years. Hence, there is a dire need for disease modifying treatments that address the underlying factors initiating and contributing to the loss of neurons in PD brain. In this regard, genetic findings in rare inherited forms of PD and histopathological observations incriminate abnormal behavior of a neuronal protein called alpha-synuclein (aSyn). The physiological function(s) of this protein remains elusive; however, under disease states, this protein forms clumps (technically: misfolded aggregates) which deposit in the nervous system and impact the normal function of neurons. Moreover, once misfolded, the putative pathogenic forms of aSyn propagate within the affected network of neurons, further compromising their function and progressive involvement of additional brain regions. Hence, modulating the factors that may promote pathological aSyn misfolding, blocking the propagation of misfolded aSyn in neuronal networks and augmenting cytoprotective response towards mitigating neuronal toxicity represent promising targets in PD therapy, and are actively being pursued in preclinical research and in clinical trials. Hence, as part of the research project , the studies described below were carried out as a contribution to discovery of disease mechanisms, and translational scientific inquiry into the potential utility of viral mediated gene delivery/gene modification in PD.
SOCIETAL IMPACT
Research into mechanisms of neuronal dysfunction caused by aSyn and establishing preclinical research paradigms to modulate aSyn neurotoxicity are needed for better understanding PD and related diseases.
OVERALL OBJECTIVES
Therefore, the overall objectives of the project were to: i) modulate the expression levels of neuronal aSyn to prevent its misfolding, ii) study the mechanisms that render neurons vulnerable to the toxicity by misfolded aSyn, and iii) provide proof-of-concept (PoC) preclinical evidence regarding the utility of gene modulation using viral vectors.
Parkinson disease (PD) is the second most common neurodegenerative disease in populations aged 60 years or above. Current estimates indicate that the clinically diagnosed PD affects more than 6 million people worldwide, and presents a significant socio-economic burden. While the underlying cause of PD remains a matter of rigorous scientific inquiry, examination of (post-mortem, deceased) patient brains shows that there is a profound loss of dopamine producing neurons in several brain regions, particularly affecting a region in midbrain called the substantia nigra (pars compacta). Based on these observations, the clinical interventions are aimed at symptomatic relief, with dopamine replacement (through L-dopa treatment) as the gold-standard approach. However, the disease is progressive and eventually current clinical therapies lose efficacy in majority of the patients after 5-10 years. Hence, there is a dire need for disease modifying treatments that address the underlying factors initiating and contributing to the loss of neurons in PD brain. In this regard, genetic findings in rare inherited forms of PD and histopathological observations incriminate abnormal behavior of a neuronal protein called alpha-synuclein (aSyn). The physiological function(s) of this protein remains elusive; however, under disease states, this protein forms clumps (technically: misfolded aggregates) which deposit in the nervous system and impact the normal function of neurons. Moreover, once misfolded, the putative pathogenic forms of aSyn propagate within the affected network of neurons, further compromising their function and progressive involvement of additional brain regions. Hence, modulating the factors that may promote pathological aSyn misfolding, blocking the propagation of misfolded aSyn in neuronal networks and augmenting cytoprotective response towards mitigating neuronal toxicity represent promising targets in PD therapy, and are actively being pursued in preclinical research and in clinical trials. Hence, as part of the research project , the studies described below were carried out as a contribution to discovery of disease mechanisms, and translational scientific inquiry into the potential utility of viral mediated gene delivery/gene modification in PD.
SOCIETAL IMPACT
Research into mechanisms of neuronal dysfunction caused by aSyn and establishing preclinical research paradigms to modulate aSyn neurotoxicity are needed for better understanding PD and related diseases.
OVERALL OBJECTIVES
Therefore, the overall objectives of the project were to: i) modulate the expression levels of neuronal aSyn to prevent its misfolding, ii) study the mechanisms that render neurons vulnerable to the toxicity by misfolded aSyn, and iii) provide proof-of-concept (PoC) preclinical evidence regarding the utility of gene modulation using viral vectors.
WORK PERFORMED
The detailed technical aspects of the work performed are accessible in the published scientific reports (Under Publications).
WP1) Validated an animal (mouse) model to study neuron-to-neuron spreading of misfolded alpha-Synuclein protein (aSyn) in the CNS, and established read-outs (biochemical, pathological and behavioral) as surrogate markers of disease progression
WP2) Characterized and validated cellular mechanisms that provide mechanistic insights into the pathological significance of aSyn aggregation in CNS
WP3) Established a preclinical PoC animal (mouse) model, to target candidate mechanisms using viral vectors is performed using minimally invasive approaches
RESULTS/OUTCOMES
WP1:
1) In a transgenic (i.e. genetically modified) mouse model of aSyn aggregation, we identified distinct neuronal populations affected by the disease long before the emergence of motor disability, and sensorimotor defects (Ferreira, Goncalves et al. 2021, Ferreira, Richner et al. 2021).
WP2:
1) We identified abnormal regulation of anti-oxidant protein NRF2 activity and aberrant cytoprotective gene response in PD - published in (Delaidelli, Richner et al. 2021). These findings have important implications for biomarker discovery, and potentially in understanding the mode of action of therapeutic candidates.
2) Ongoing work includes the application of advanced gene expression platforms (tissue transcriptomics and next generation sequencing) to further refine the pathogenic relevance of aSyn aggregation and neuronal vulnerability in disease (unpublished; expected by the end of 2021)
WP3:
1) Optimized the delivery of tools for ectopic (i.e. artificial) expression of human genes and/or genetic modification in the mouse nervous system tissue, using a minimally invasive route (intramuscular- IM) for the delivery of recombinant adeno-associated virus (rAAV) particles. Published in Jan A et al. 2019.
2) Using the rAAV2/6 vehicle, we delivered gene modifying reagents (technically: guide RNAs for CRISPR/Cas9 nuclease) towards disrupting the locus of aSyn (technically: SNCA gene) in the cells of nervous system of aSyn mice (see WP1-1), and followed the disease progression- ongoing work.
OUTCOME/DISSEMINATION ACTIVITIES
1- Peer reviewed publications: 5- All publications are open-access online and freely available to members of public.
2- Institutional websites: The publications and findings were disseminated on the Aarhus university website, the website of Danish Research Institute of Translational Neuroscience and communicated to all stakeholders (via email)
3- Social Media: The links to open-access publications and summary of findings were made available via LinkedIn, Twitter and Facebook pages accounts of the applicant, collaborators and the institution.
The detailed technical aspects of the work performed are accessible in the published scientific reports (Under Publications).
WP1) Validated an animal (mouse) model to study neuron-to-neuron spreading of misfolded alpha-Synuclein protein (aSyn) in the CNS, and established read-outs (biochemical, pathological and behavioral) as surrogate markers of disease progression
WP2) Characterized and validated cellular mechanisms that provide mechanistic insights into the pathological significance of aSyn aggregation in CNS
WP3) Established a preclinical PoC animal (mouse) model, to target candidate mechanisms using viral vectors is performed using minimally invasive approaches
RESULTS/OUTCOMES
WP1:
1) In a transgenic (i.e. genetically modified) mouse model of aSyn aggregation, we identified distinct neuronal populations affected by the disease long before the emergence of motor disability, and sensorimotor defects (Ferreira, Goncalves et al. 2021, Ferreira, Richner et al. 2021).
WP2:
1) We identified abnormal regulation of anti-oxidant protein NRF2 activity and aberrant cytoprotective gene response in PD - published in (Delaidelli, Richner et al. 2021). These findings have important implications for biomarker discovery, and potentially in understanding the mode of action of therapeutic candidates.
2) Ongoing work includes the application of advanced gene expression platforms (tissue transcriptomics and next generation sequencing) to further refine the pathogenic relevance of aSyn aggregation and neuronal vulnerability in disease (unpublished; expected by the end of 2021)
WP3:
1) Optimized the delivery of tools for ectopic (i.e. artificial) expression of human genes and/or genetic modification in the mouse nervous system tissue, using a minimally invasive route (intramuscular- IM) for the delivery of recombinant adeno-associated virus (rAAV) particles. Published in Jan A et al. 2019.
2) Using the rAAV2/6 vehicle, we delivered gene modifying reagents (technically: guide RNAs for CRISPR/Cas9 nuclease) towards disrupting the locus of aSyn (technically: SNCA gene) in the cells of nervous system of aSyn mice (see WP1-1), and followed the disease progression- ongoing work.
OUTCOME/DISSEMINATION ACTIVITIES
1- Peer reviewed publications: 5- All publications are open-access online and freely available to members of public.
2- Institutional websites: The publications and findings were disseminated on the Aarhus university website, the website of Danish Research Institute of Translational Neuroscience and communicated to all stakeholders (via email)
3- Social Media: The links to open-access publications and summary of findings were made available via LinkedIn, Twitter and Facebook pages accounts of the applicant, collaborators and the institution.
The studies outlined above constitute ambitious and challenging projects, with the highly specified aim of experimental model development and/or refinement that are aligned with the findings in clinical PD patients or known pathological mechanisms in PD. In other words, the tools developed and/or mechanisms discovered are expected to have a significant impact on preclinical research towards discovery in the area of biomarkers (of disease progression) and gaining insights regarding mechanism based therapies in PD and related diseases.
IMPACT
1) Scientific impact: These studies have been instrumental in providing scientific community (researchers working on PD, and related neurodegenerative diseases) with a wealth of mechanistic insights regarding the role of pathological protein aggregation in nervous system, and relevant mechanisms in disease
2) Career impact: The applicant greatly benefitted from the project, both in terms of career achievements and the development of strong professional network. In addition to the 5 journal articles (3 of which as the corresponding author), the applicant presented the data at 2 international (virtual) conferences and established strategic collaboration with renowned experts in neurodegeneration research (Denmark, USA, Canada, Germany, Australia).
3) Societal impact: In concerted efforts between academic and industry, we anticipate that this work will lay the scientific foundations for novel diagnostic assays (e.g. monitor disease progression, identify underlying cause of symptomatology), and potentially facilitate refined approaches in therapeutic intervention.
IMPACT
1) Scientific impact: These studies have been instrumental in providing scientific community (researchers working on PD, and related neurodegenerative diseases) with a wealth of mechanistic insights regarding the role of pathological protein aggregation in nervous system, and relevant mechanisms in disease
2) Career impact: The applicant greatly benefitted from the project, both in terms of career achievements and the development of strong professional network. In addition to the 5 journal articles (3 of which as the corresponding author), the applicant presented the data at 2 international (virtual) conferences and established strategic collaboration with renowned experts in neurodegeneration research (Denmark, USA, Canada, Germany, Australia).
3) Societal impact: In concerted efforts between academic and industry, we anticipate that this work will lay the scientific foundations for novel diagnostic assays (e.g. monitor disease progression, identify underlying cause of symptomatology), and potentially facilitate refined approaches in therapeutic intervention.