S100A8 Protein Calgranulin A is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
| Symbol | S100A8 |
| Full Name | S100 Calcium Binding Protein A8 |
| Aliases | Calgranulin A, MRP8, Myeloid-related protein 8 |
| Molecular Weight | 10.8 kDa |
| Protein Family | S100 EF-hand calcium-binding proteins |
| Associated Diseases | AD, PD, ALS, MS, Rheumatoid Arthritis, Inflammatory Bowel Disease |
S100A8 (S100 Calcium Binding Protein A8), also known as Calgranulin A or Myeloid-Related Protein 8 (MRP8), is a member of the S100 family of EF-hand calcium-binding proteins. It forms a heterodimer with S100A9 (calprotectin) and plays critical roles in inflammation, immune cell recruitment, and neuroinflammation. In the central nervous system, S100A8 is expressed in activated microglia, astrocytes, and infiltrating immune cells, where it contributes to the neuroinflammatory cascade observed in neurodegenerative diseases.
S100A8 is a small calcium-binding protein (10.8 kDa) containing two EF-hand motifs. The N-terminal EF-hand is a low-affinity calcium-binding site, while the C-terminal EF-hand is a high-affinity binding site. Upon calcium binding, S100A8 undergoes conformational changes that expose hydrophobic regions, enabling protein-protein interactions and dimerization with S100A9.
S100A8/A9 is elevated in AD brain tissue and CSF, colocalizing with amyloid plaques and activated microglia. The protein promotes microglial activation and neuroinflammation through TLR4 and RAGE signaling. Therapeutic strategies include anti-S100A8/A9 antibodies and TLR4 inhibitors.
Elevated S100A8 expression in PD substantia nigra and CSF. Contributes to microglial activation and dopaminergic neuron loss. May serve as a biomarker for disease progression.
S100A8/A9 upregulation in ALS spinal cord microglia. Associated with disease progression and inflammatory response. Correlates with microglial marker IBA1.
Central role in demyelination and lesion formation. Therapeutic targeting with S100A9 inhibitors shows promise in experimental models.
| Approach | Status | Description |
|---|---|---|
| Anti-S100A8/A9 antibodies | Preclinical | Monoclonal antibodies to neutralize calprotectin |
| TLR4 inhibitors | Preclinical | Small molecules blocking TLR4 activation |
| RAGE antagonists | Preclinical | Blocking RAGE-mediated inflammation |
| Calcium channel modulators | Research | Modulating calcium-dependent activation |
The study of S100A8 Protein Calgranulin A 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.