Sigma-2 receptor modulation therapy represents a novel therapeutic approach for neurodegenerative diseases, particularly Alzheimer's disease (AD) and Parkinson's disease (PD). The sigma-2 receptor (also known as PPHLN1) is a unique transmembrane protein distinct from the sigma-1 receptor, and its modulation offers neuroprotective effects through multiple mechanisms including synaptic protection, ER stress modulation, calcium homeostasis, and autophagy regulation[1][2].
The sigma-2 receptor is a key regulator of synaptic function and neuronal survival. Sigma-2 receptor antagonists such as CT1812 (selenex) prevent synaptic loss through several mechanisms:
Sigma-2 receptors are localized to the endoplasmic reticulum (ER), where they play critical roles in cellular stress response[2:1]:
The sigma-2 receptor modulates calcium signaling through[1:1][3]:
Sigma-2 modulation affects cellular clearance mechanisms[2:2]:
Preclinical studies have demonstrated sigma-2 receptor-mediated neuroprotection in AD models:
In PD models, sigma-2 modulation shows promise for[4]:
CT1812 is a first-in-class small molecule sigma-2 receptor antagonist developed by Cognition Therapeutics (now part of Novartis)[1:2][2:3]:
| Study Phase | Indication | Status |
|---|---|---|
| Phase 1 | Alzheimer's disease | Completed |
| Phase 2 | Alzheimer's disease (START study) | Clinical |
| Phase 2 | Dementia with Lewy Bodies | Planning |
| Phase 1 | Dry age-related macular degeneration | Completed |
Key Properties:
Phase 1 Results:
Phase 2 START Study:
| Compound | Indication | Development Stage |
|---|---|---|
| CT1812 | Alzheimer's disease | Phase 2 |
| CT1812 | Dementia with Lewy Bodies | Phase 2 (planning) |
| CT1964 | Parkinson's disease | Preclinical |
Sigma-2 receptor modulators have demonstrated a favorable safety profile in clinical trials[1:3]:
Sigma-2 modulation offers advantages over existing AD therapeutics:
| Approach | Mechanism | Advantages of Sigma-2 |
|---|---|---|
| Amyloid antibodies | Immun clearance | Direct synaptic protection, no ARIA |
| BACE inhibitors | Amyloid reduction | Broader mechanism, safer profile |
| Tau-targeted | Tau reduction | Addresses multiple pathologies |
| Symptomatic | Cholinergic | Disease-modifying potential |
CT1812 Phase 1 Results - Alzheimer's & Dementia 2020. 2020. ↩︎ ↩︎ ↩︎ ↩︎
Sigma-2 Receptor and Synaptic Function - Nature Neuroscience 2019. 2019. ↩︎ ↩︎ ↩︎ ↩︎
Calcium Signaling in Neurodegeneration - Cell 2020. 2020. ↩︎
Sigma-2 Receptor in Parkinson's Disease Models - Neurobiology of Disease 2021. 2021. ↩︎