Calcium Dysregulation In Neurodegeneration is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Calcium (Ca²⁺) is a critical second messenger that regulates neuronal survival, synaptic plasticity, gene expression, and metabolic homeostasis. Dysregulation of calcium homeostasis is a hallmark of virtually all neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and Huntington's disease (HD). The "calcium hypothesis" of neurodegeneration posits that chronic perturbation of neuronal calcium signaling leads to mitochondrial dysfunction, oxidative stress, protease activation, and ultimately neuronal death.
flowchart TD
A[Normal Calcium Signaling] --> B[Calcium Dysregulation Trigger] -->
B --> C[ER Calcium Store Depletion] -->
B --> D[Plasma Membrane Channel Dysfunction] -->
B --> E[Mitochondrial Calcium Overload] -->
B --> F[Calcium Buffer System Failure] -->
C --> G[ER Stress/UPR Activation] -->
C --> H[Calpain Activation] -->
D --> I[Excitotoxicity)
D --> J[NMDA receptor) Receptor Overactivation] -->
E --> K[Mitochondrial Permeability Transition] -->
E --> L[ROS Generation] -->
F --> M[Calbindin/Calretinin Loss] -->
G --> N[Apoptotic Signaling] -->
H --> N
I --> N
J --> N
K --> L
L --> O[Oxidative Stress)
M --> O
N --> P[Gene Expression Changes] -->
O --> P
P --> Q[Synaptic Dysfunction)
Q --> R[Neuronal Death]
style A fill:#90EE90
style R fill:#FFB6C1
Neuronal calcium influx occurs through multiple pathways, each of which can become dysregulated in disease:
| Channel Type |
Normal Function |
Dysregulation in Disease |
| Voltage-Gated Calcium Channels (VGCCs) |
Depolarization-induced Ca²⁺ entry for neurotransmitter release |
L-type channel upregulation in AD; N-type channel dysfunction in ALS |
| NMDA Receptors |
Glutamate-induced Ca²⁺ influx for synaptic plasticity |
Overactivation causes excitotoxicity in AD, PD, ALS |
| AMPA/Kainate Receptors |
Fast excitatory synaptic transmission |
GluA2 subunit deficiency increases Ca²⁺ permeability in ALS |
| TRPM Channels |
Stretch/mechano-sensitive Ca²⁺ entry |
TRPM2 activation in AD microglia; TRPM7 in PD |
| Store-Operated Channels (ORAI/STIM) |
ER Ca²⁺ depletion-activated entry |
ORAI1 dysfunction in AD |
| P2X Receptor Channels |
ATP-gated cation channels |
P2X7 activation in neuroinflammation |
¶ Calcium Storage and Release
flowchart LR
subgraph ER_Calcium
A[ER Calcium Store] -->|Release| B[IP3 Receptors] -->
A -->|Release| C[Ryanodine Receptors]
end
subgraph Cytosol
D[Cytosolic Ca²⁺] -->|Buffer| E[Calbindin] -->
D -->|Buffer| F[Calretinin] -->
D -->|Buffer| G[Parvalbumin] -->
D -->|Buffer| H[CaBP Proteins]
end
subgraph Mitochondria
D -->|Uptake| I[MCU Complex] -->
I -->|Release| J[mPTP/NHE]
end
subgraph Recovery
D -->|Extrude| K[PMCA Pump] -->
D -->|Extrude| L[NCX] -->
D -->|Reuptake| M[SERCA Pump] -->
M --> A
end
A -.->|Leak| D
style A fill:#FFE4B5
style D fill:#FFE4B5
The endoplasmic reticulum (ER) serves as the major intracellular calcium store. Key components include:
- SERCA (Sarco/Endoplasmic Reticulum Ca²⁺-ATPase): Pumps Ca²⁺ into ER; downregulated in AD
- IP3 Receptors: ER Ca²⁺ release channels activated by phospholipase C signaling
- Ryanodine Receptors: ER Ca²⁺ release channels activated by caffeine and depolarization
- Calretinin, Calbindin, Parvalbumin: Cytosolic calcium buffer proteins that prevent toxicity
In AD, calcium dysregulation occurs through multiple interconnected pathways:
- Amyloid-beta (Aβ) interaction with membranes: Aβ forms calcium-permeable channels in neuronal membranes
- Presenilin mutations: PSEN1/PSEN2 mutations alter ER calcium homeostasis by affecting SERCA function
- NMDA receptor dysfunction: Aβ-induced overactivation leads to excitotoxicity
- Mitochondrial calcium overload: Aβ accumulation in mitochondria disrupts calcium buffering
flowchart TD
A[Aβ Oligomers] --> B[Membrane Channel Formation] -->
A --> C[VGCC Activation] -->
A --> D[NMDAR Overactivation] -->
A --> E[Mitochondrial Accumulation] -->
B --> F[Ca²⁺ Influx] -->
C --> F
D --> G[Excitotoxicity)
E --> H[Mitochondrial Dysfunction)
F --> I[Calpain Activation] -->
G --> I
H --> I
I --> J[Tau Hyperphosphorylation)
I --> K[Synaptic Loss)
J --> L[NFT Formation] -->
K --> M[Neuronal Death] -->
L --> M
Key molecular events in AD calcium dysregulation include:
- Increased basal cytosolic calcium in neurons harboring PSEN1 mutations
- Enhanced calcium-induced calcium release through ryanodine receptors
- Reduced expression of calcium buffer proteins (calbindin, calretinin)
- Elevated resting calcium levels in microglia promoting neuroinflammation
Calcium dysregulation in PD is particularly prominent in dopaminergic neurons of the substantia nigra pars compacta (SNpc) due to their unique electrophysiological properties:
- Autonomous pacemaking: L-type calcium channels (Cav1.3) drive rhythmic firing, creating sustained calcium influx
- Mitochondrial complex I deficiency: Impairs calcium buffering and ATP production
- Alpha-synuclein toxicity: Affects ER-mitochondria contact sites (MAMs)
- LRRK2 mutations: Dysregulate calcium homeostasis through kinase-dependent mechanisms
| Factor |
Effect on Calcium |
Therapeutic Target |
| L-type channels (Cav1.3) |
Chronic Ca²⁺ influx |
Isradipine, amlodipine |
| Mitochondrial dysfunction |
Impaired Ca²⁺ sequestration |
CoQ10, MitoQ |
| α-Synuclein |
ER-mitochondria calcium mishandling |
Immunotherapy |
| DJ-1 mutations |
Oxidative stress + Ca²⁺ dysregulation |
Antioxidants |
Calcium dysregulation in motor neurons involves:
- ** glutamate excitotoxicity via AMPA receptors**: Reduced GluA2 subunit expression increases Ca²⁺ permeability
- Voltage-gated calcium channel dysfunction: Mutations in CACNA1A (P/Q-type) and other VGCCs
- ER stress: Motor neurons are particularly sensitive to ER calcium depletion
- Mitochondrial calcium handling: Mutations in SOD1, C9orf72, FUS affect mitochondrial calcium
In HD, calcium dysregulation occurs through:
- Mutant huntingtin (mHtt) interactions with N-type calcium channels: Increased channel activity
- ER stress: mHtt disrupts ER calcium stores and store-operated calcium entry
- Mitochondrial dysfunction: Impaired calcium buffering capacity
- Enhanced NMDA receptor activity: Excitotoxicity
Calpains are calcium-dependent cysteine proteases that execute proteolytic cell death:
- Calpain-1 (μ-calpain): Activated at micromolar Ca²⁺ concentrations
- Calpain-2 (m-calpain): Activated at millimolar Ca²⁺ concentrations
Substrates include:
- Cytoskeletal proteins (spectrin, tau, neurofilaments)
- Membrane proteins (glutamate receptors, ion channels)
- Transcription factors
- Apoptotic proteins (Bcl-2 family members)
Excessive mitochondrial calcium accumulation triggers the mitochondrial permeability transition pore (mPTP):
flowchart TD
A[Mitochondrial Ca²⁺ Overload] --> B[ROS Generation] -->
A --> C[ATP Depletion] -->
A --> D[Oxidized Pyridine Nucleotides] -->
B --> E[mPTP Opening] -->
C --> E
D --> E
E --> F[Cyt c Release] -->
E --> G[ATP Depletion] -->
E --> H[Membrane Potential Loss] -->
F --> I[Apoptosis)
G --> I
H --> I
| Drug/Compound |
Target |
Disease |
Status |
| Isradipine |
L-type VGCC (Cav1.3) |
PD |
Phase 3 clinical trials |
| Amlodipine |
L-type VGCC |
PD |
Observational studies |
| Nimodipine |
L-type VGCC |
AD |
Phase 2 trials |
| Memantine |
NMDA receptor](/entities/nmda-receptor) receptor |
AD |
Approved (moderate efficacy) |
| Sodium butyrate |
HDAC inhibitor, modulates Ca²⁺ |
AD, HD |
Preclinical |
- Coenzyme Q10: Improves mitochondrial calcium handling; failed in Phase 3 for PD
- MitoQ (mitoquinone): M-targeted antioxidant; in clinical trials
- SS-31 (elamipretide): Stabilizes mitochondrial membrane; in trials for AD/PD
- Ciclosporin A: Inhibits cyclophilin D (mPTP component); neuroprotective in models
- Calbindin gene therapy: Protective in AD mouse models
- Parvalbumin overexpression: Prevents excitotoxicity
- Calcium-chelating agents (BAPTA derivatives): Used experimentally
- Dantrolene: Ryanodine receptor antagonist; in trials for ALS
- Sarcoendoplasmic reticulum calcium ATPase (SERCA) activators: In development
- IP3 receptor antagonists: In development for AD
- Calpain inhibitors: Neuroprotective in models; challenge with blood-brain barrier penetration
- Caspase inhibitors: Prevent calcium-dependent apoptotic cascades
- Autophagy enhancers: Clear damaged mitochondria (mitophagy)
| Biomarker |
Source |
Disease Association |
Utility |
| Resting cytosolic Ca²⁺ |
Induced neurons from iPSCs |
AD (elevated) |
Research |
| Store-operated Ca²⁺ entry |
Lymphoblasts |
AD (reduced) |
Research |
| Calpain-generated spectrin fragments |
CSF, blood |
AD, TBI |
Biomarker |
| Calbindin levels |
Brain tissue |
AD (reduced) |
Diagnostic |
| ER calcium release |
Patient-derived cells |
AD (enhanced) |
Research |
Calcium dysregulation intersects with virtually every other neurodegenerative mechanism:
The study of Calcium Dysregulation In Neurodegeneration has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
- Berridge MJ. Calcium hypothesis of Alzheimer's disease. Pflügers Arch. 2010;459(3):441-449. DOI:10.1007/s00424-009-0736-1
- Mattson MP. Calcium and neurodegeneration. Aging Cell. 2007;6(3):337-350. DOI:10.1111/j.1474-9726.2007.00279.x
- Green KN, LaFerla FM. Linking calcium to Aβ and Alzheimer's disease. Neuron. 2008;59(2):190-194. DOI:10.1016/j.neuron.2008.07.013
- Surmeier DJ, Schumacker PT, Guzman JD, et al. Calcium and Parkinson's disease. Biochem Biophys Res Commun. 2017;483(4):1013-1019. DOI:10.1016/j.bbrc.2016.08.168
- Chan CS, Gertler TS, Surmeier DJ. Calcium homeostasis, selective vulnerability and Parkinson's disease. Trends Neurosci. 2009;32(5):249-256. DOI:10.1016/j.tins.2009.01.005
- Jaiswal MK. Calcium, mitochondria, and the pathogenesis of ALS: The pathomechanism of the disease. Neurosci Lett. 2019;696:129-138. DOI:10.1016/j.neulet.2018.12.021
- Bezprozvanny I, Mattson MP. Neuronal calcium mishandling and the collapse of mitochondrial homeostasis in Alzheimer's disease. Antioxid Redox Signal. 2008;10(4):635-640. DOI:10.1089/ars.2007.1927
- Khachaturian ZS. Calcium, membranes, and amyloidogenesis: Is there a common pathomechanism? J Neurosci Res. 1989;23(4):407-414. DOI:10.1002/jnr.490230403
- Popugaeva E, Pchitskaya E, Bezprozvanny I. Dysregulation of intracellular calcium signaling in Alzheimer's disease. Mol Neurobiol. 2018;55(7):5767-5779. DOI:10.1007/s12035-017-0770-5
- Hirsch EC, Brandel JP, Galle P, et al. Iron and aluminum increase in the substantia nigra of patients with Parkinson's disease: An X-ray microanalysis. J Neurochem. 1991;56(2):446-451. DOI:10.1111/j.1471-4159.1991.tb08207.x
🔴 Low Confidence
| Dimension |
Score |
| Supporting Studies |
10 references |
| Replication |
0% |
| Effect Sizes |
25% |
| Contradicting Evidence |
0% |
| Mechanistic Completeness |
50% |
Overall Confidence: 31%