circRNA Dysfunction Restoration is a novel therapeutic approach that aims to restore levels of neuroprotective circular RNAs (circRNAs) in the aging and neurodegenerative brain. CircRNAs are covalently closed, stable non-coding RNAs that function primarily as microRNA "sponges" and regulators of gene expression. Several neuroprotective circRNAs decline with age and in Alzheimer's disease, Parkinson's disease, and ALS, contributing to synaptic dysfunction and neuronal vulnerability. This therapy uses antisense oligonucleotides (ASOs) or CRISPR-based approaches to restore these protective circRNAs. [1] [2]
| Attribute | Value |
|---|---|
| Therapy Name | circRNA Dysfunction Restoration |
| Category | Novel target |
| Target Diseases | Alzheimer's Disease, Parkinson's Disease, ALS |
| Total Score | 71/100 |
| AD Score | 8/10 |
| PD Score | 8/10 |
| ALS Score | 6/10 |
| FTD Score | 6/10 |
| Aging Score | 7/10 |
Circular RNAs (circRNAs) are formed through back-splicing, a process where a downstream 5' splice site connects to an upstream 3' splice site, creating a covalently closed loop structure. This structure makes circRNAs highly stable, resistant to exonuclease degradation, and long-lived in cells—properties that make them attractive as therapeutic targets. [3]
Key neuroprotective circRNAs include:
CDR1as (circRNA-7 / ciRS-7): The most well-characterized circRNA, CDR1as acts as a potent sponge for miR-7, a microRNA that regulates many neuronal genes. CDR1as contains over 70 miR-7 binding sites, sequestering miR-7 and preventing it from repressing target mRNAs involved in synaptic function, neuroprotection, and protein quality control. [4]
circSAMD4A: A circRNA that is downregulated in AD brains and regulates synaptic plasticity through miR-138 sequestration. [5]
circH1PRX: A circular RNA that declines in AD and regulates genes involved in amyloid-beta metabolism. [6]
circTLK2: Implicated in PD pathogenesis; regulates neuronal survival through miR-106b binding. [7]
circSCFD2: Involved in axonal guidance and synaptic function; declines in multiple neurodegenerative conditions. [8]
The "circRNA dysfunction" hypothesis proposes that:
Restoring circRNA levels could:
Approach 1: ASO-Mediated circRNA Upregulation
Approach 2: circRNA Mimetics (Direct Administration)
Approach 3: CRISPR Activation
| CircRNA | Disease | Primary Target | Priority |
|---|---|---|---|
| CDR1as | AD, PD | miR-7 sequestration | Highest |
| circSAMD4A | AD | Synaptic plasticity | High |
| circTLK2 | PD | Neuronal survival | High |
| circH1PRX | AD | Amyloid metabolism | Medium |
Year 1: Target Validation
Year 2: Lead Optimization
Year 3: Disease Model Testing
Year 4: IND-Enabling Studies
Phase 1 (Year 5): Safety in healthy volunteers
Phase 2 (Year 6-7): Efficacy signal in AD or PD
Phase 3 (Year 8): Registration trial
| Risk | Likelihood | Impact | Mitigation |
|---|---|---|---|
| Insufficient CNS delivery | High | High | Multiple delivery platforms; intranasal route |
| Off-target microRNA effects | Medium | Medium | Careful ASO design; control sequences |
| Lack of efficacy | Medium | High | Multiple targets; biomarker-driven patient selection |
| Manufacturing challenges | Medium | Medium | Early manufacturing engagement |
| Dimension | Score | Rationale |
|---|---|---|
| Novelty | 9/10/10 | circRNA therapeutics are highly novel; very early stage for neurodegeneration |
| Mechanistic Rationale | 6/10/10 | circRNAs regulate gene expression; mechanism of therapeutic restoration unclear |
| Addresses Root Cause | 6/10/10 | Addresses regulatory dysfunction; indirect effect on core pathology |
| Delivery Feasibility | 4/10/10 | RNA delivery to brain extremely challenging; AAV or lipid nanoparticles needed |
| Safety Plausibility | 6/10/10 | Gene therapy safety profile; off-target effects possible |
| Combinability | 5/10/10 | Novel mechanism; limited combination data available |
| Biomarker Availability | 5/10/10 | circRNA detection in CSF possible but not validated for therapy monitoring |
| De-risking Path | 4/10/10 | Very early stage; significant research needed before clinical translation |
| Multi-disease Potential | 6/10/10 | Potential for multiple diseases; mechanism not disease-specific |
| Patient Impact | 6/10/10 | High long-term potential; currently speculative |
| Total | 57/100 |
Hanan et al. circRNAs in neurodegeneration (2022). 2022. ↩︎
Kumar et al. Circular RNAs as therapeutic targets (2023). 2023. ↩︎
Kristensen et al. The biogenesis, biology, and function of circRNAs (2022). 2022. ↩︎
Hansen et al. CDR1as functions as a miR-7 sponge (2013). 2013. ↩︎
Dube et al. circSAMD4A in synaptic function (2019). 2019. ↩︎
Zhang et al. circH1PRX in AD (2021). 2021. ↩︎
Jin et al. circTLK2 in PD (2022). 2022. ↩︎
Ahmad et al. circRNA decline in neurodegeneration (2023). 2023. ↩︎
Rigo et al. ASO-mediated splicing modulation (2014). 2014. ↩︎
Wesselhoeft et al. Engineering circular RNA (2019). 2019. ↩︎
Ruan et al. CRISPR activation of circRNA (2021). 2021. ↩︎
Piwecka et al. Loss of CDR1as leads to dysfunction (2017). 2017. ↩︎
Zhang et al. AAV-CDR1as improves cognition (2022). 2022. ↩︎
Lukiw et al. CDR1as decline in AD (2018). 2018. ↩︎
Saugstad et al. miR-7 in neurodegeneration (2022). 2022. ↩︎
Dube et al. circSAMD4A neuronal function (2020). 2020. ↩︎
Chen et al. circTLK2 dopaminergic toxicity (2023). 2023. ↩︎
Grasso et al. circRNA and cognitive aging (2021). 2021. ↩︎
Bhamja et al. circRNA biomarkers in neurodegeneration (2022). 2022. ↩︎
Siegel et al. CDR1as in CSF (2021). 2021. ↩︎
Hanan et al. Blood circRNA signatures for AD/PD (2020). 2020. ↩︎