Related Diseases: [Corticobasal Degeneration](/diseases/corticobasal-degeneration), [Progressive Supranuclear Palsy](/diseases/progressive-supranuclear-palsy), [Alzheimer's Disease](/diseases/alzheimers-disease)
Related Pathways: [Tauopathies](/mechanisms/tauopathies), [Protein Aggregation](/mechanisms/protein-aggregation), [Neuroinflammation](/mechanisms/neuroinflammation)
Related Proteins: [Tau](/proteins/tau-protein), [4R Tau](/proteins/4r-tau-protein), [Neurofilament Light Chain](/proteins/neurofilament-light-chain)
Related Biomarkers: [CSF Biomarkers](/biomarkers/csf-biomarkers), [Blood Biomarkers](/biomarkers/blood-biomarkers-neurodegeneration)
CBD Proteomics
Introduction
Proteomics studies in corticobasal degeneration (CBD) have revealed distinctive molecular signatures in brain tissue and biofluids. These studies provide insights into the pathogenic mechanisms underlying this 4R tauopathy and help distinguish CBD from related neurodegenerative disorders.
Cerebrospinal Fluid Proteomics
CSF Protein Alterations in CBD
A key study identified altered cerebrospinal fluid proteins in CBD patients compared to controls[@paslawski2021]. These findings help characterize the molecular landscape of CBD and identify potential biomarker candidates.
Network Analysis of CSF Proteome
Large-scale network analysis of CSF proteome has identified molecular signatures in frontotemporal lobar degeneration spectrum disorders including CBD[@saloner2025]:
...Related Diseases: [Corticobasal Degeneration](/diseases/corticobasal-degeneration), [Progressive Supranuclear Palsy](/diseases/progressive-supranuclear-palsy), [Alzheimer's Disease](/diseases/alzheimers-disease)
Related Pathways: [Tauopathies](/mechanisms/tauopathies), [Protein Aggregation](/mechanisms/protein-aggregation), [Neuroinflammation](/mechanisms/neuroinflammation)
Related Proteins: [Tau](/proteins/tau-protein), [4R Tau](/proteins/4r-tau-protein), [Neurofilament Light Chain](/proteins/neurofilament-light-chain)
Related Biomarkers: [CSF Biomarkers](/biomarkers/csf-biomarkers), [Blood Biomarkers](/biomarkers/blood-biomarkers-neurodegeneration)
CBD Proteomics
Introduction
Proteomics studies in corticobasal degeneration (CBD) have revealed distinctive molecular signatures in brain tissue and biofluids. These studies provide insights into the pathogenic mechanisms underlying this 4R tauopathy and help distinguish CBD from related neurodegenerative disorders.
Cerebrospinal Fluid Proteomics
CSF Protein Alterations in CBD
A key study identified altered cerebrospinal fluid proteins in CBD patients compared to controls[@paslawski2021]. These findings help characterize the molecular landscape of CBD and identify potential biomarker candidates.
Network Analysis of CSF Proteome
Large-scale network analysis of CSF proteome has identified molecular signatures in frontotemporal lobar degeneration spectrum disorders including CBD[@saloner2025]:
- RNA splicing modules: Increased abundance, particularly associated with genetic forms
- Extracellular matrix modules: Altered in MAPT mutation carriers
- Synaptic/neuronal modules: Decreased abundance
- Autophagy modules: Decreased abundance
Network-based proteomics has identified replicable molecular pathways and hub proteins that may serve as candidate biomarkers and therapeutic targets.
Brain Tissue Proteomics
Early Proteomic Studies
An early proteomic analysis using two-dimensional gel electrophoresis identified specific protein changes in CBD brain tissue[@chen2005]:
Upregulated Proteins:
- Protein-L-isoaspartate (D-aspartate) O-methyltransferase (PIMT)
- Cofilin 1 (non-muscle)
Downregulated Proteins:
- Carbonyl reductase [NADPH] 1
- Peptidyl-prolyl cis-trans isomerase A (two isoforms)
- Ubiquitin carboxyl-terminal hydrolase isozyme L1 (UCH-L1)
- Phosphoglycerate mutase 1 (brain)
- Peroxiredoxin 5
These proteins are involved in protein quality control, energy metabolism, and oxidative stress response—all pathways relevant to neurodegeneration.
Soluble and Insoluble Proteome Differences
Recent studies using sarkosyl fractionation have characterized the soluble and insoluble proteome in primary tauopathies[@kavanagh2025]:
- CBD and Pick's disease (PiD) showed the greatest proteomic similarity in both soluble and insoluble fractions
- PSP was the most divergent compared to other tauopathies
- Key solubility changes observed in:
- Lysosomal regulators
- Postsynaptic proteins
- Extracellular matrix (ECM)
- Mitochondrial proteins
SORT1 (Sortilin-1) is highly insoluble in CBD and aggregates to different extents across tauopathies.
ROCK1 and
JAK2 show shifts in solubility for key signaling pathways.
Phospho-Tau-Associated Proteomes
ProPPr (Probe-dependent Proximity Profiling) analysis has identified tau aggregate-associated proteins in CBD[@morderer2025]:
Common to All Tauopathies (229 proteins):
- VPS35 (retromer complex component)
- LAMP2 (lysosomal membrane protein)
CBD-Specific Findings:
- FTL (Ferritin light chain): Notably found in CBD astrocytic plaques with FTL-positive microglia
- Disease-specific protein associations distinguish CBD from AD, PiD, and PSP
Pathway Enrichment Analysis
Mitochondrial Proteins
CBD brain tissue shows alterations in mitochondrial proteins involved in:
- Oxidative phosphorylation
- Energy metabolism
- Reactive oxygen species defense (peroxiredoxin 5 downregulation)
Synaptic Proteins
CSF and brain tissue proteomics consistently show:
- Decreased synaptic/neuronal protein modules
- Postsynaptic protein solubility changes
- Implications for synaptic dysfunction in CBD
Lysosomal Pathway
CBD shows unique lysosomal protein insolubility patterns:
- Lysosomal regulators show altered solubility
- LAMP2 association with CBD inclusions
- Distinct lysosomal profiles compared to PSP and PiD
ECM alterations in CBD include:
- Changes in ECM protein modules in CSF
- Sortilin-1 (SORT1) aggregation
- Connections to neuroinflammation
Comparison with Other Tauopathies
| Feature | CBD | PSP | AD | PiD |
|---------|-----|-----|----|----|
| 4R Tau | +++ | +++ | +/- | - |
| TDP-43 | ++ | - | + | - |
| Synaptic Loss | ++ | ++ | +++ | + |
| Lysosomal Changes | ++ | + | + | + |
| Similarity to CBD | — | Moderate | Low | High |
CBD and PiD show the greatest proteomic similarity, while PSP is most divergent[@kavanagh2025].
Key Proteins in CBD Proteomics
| Protein | Change | Pathway | Reference |
|---------|--------|---------|-----------|
| PIMT | Upregulated | Protein repair | [@chen2005] |
| Cofilin 1 | Upregulated | Cytoskeleton | [@chen2005] |
| UCH-L1 | Downregulated | Protein degradation | [@chen2005] |
| PRDX5 | Downregulated | Oxidative stress | [@chen2005] |
| SORT1 | Highly insoluble | Lysosomal/ECM | [@kavanagh2025] |
| FTL | Insoluble (specific) | Iron metabolism | [@morderer2025] |
| VPS35 | Associated | Retromer | [@morderer2025] |
| LAMP2 | Associated | Lysosomal | [@morderer2025] |
Blood/Plasma Proteomics
Blood-Based Biomarkers in CBD
While direct proteomic profiling of CBD brain tissue and CSF provides detailed mechanistic insights, blood-based proteomics offers minimally invasive biomarker candidates for diagnosis and disease monitoring.
Neurofilament Light Chain (NfL)
- Elevated in CBD: Plasma and serum NfL levels are significantly elevated in CBD compared to controls[@default2024]
- Higher than PSP: CBD shows higher NfL than PSP, potentially reflecting more rapid cortical degeneration
- Disease progression marker: NfL levels correlate with disease severity and rate of progression
- Utility: Useful for tracking treatment response in clinical trials
Phosphorylated Tau (p-Tau)
- p-tau181: Elevated in CBD vs. controls; may help distinguish CBD from PSP
- p-tau217: Shows promise for distinguishing 4R tauopathies from AD
- p-tau231: Correlates with disease severity in CBD
- 4R tauopathy-specific p-tau assays under development
Glial Fibrillary Acidic Protein (GFAP)
- Astrocytic marker: GFAP reflects astrocyte activation in CBD
- Elevated in CBD: Higher than in PSP, consistent with prominent astrocytic pathology
- Correlates with disease: Levels correlate with clinical measures
Emerging studies on plasma extracellular vesicles (EVs) provide cell-type-specific proteomic signatures:
- Neuron-derived EVs: Show altered tau and synaptic protein content
- Astrocyte-derived EVs: Reflect astrocytic dysfunction in CBD
- Comparison with CSF: EV proteomics may complement CSF findings
Comparison: Blood vs. CSF vs. Brain Tissue
| Biomarker | Blood | CSF | Brain Tissue |
|-----------|-------|-----|--------------|
| NfL | +++ (elevated) | +++ (elevated) | N/A |
| p-tau | ++ (mildly elevated) | +++ (elevated) | +++ (aggregated) |
| GFAP | ++ (elevated) | + (elevated) | +++ (reactive astrocytes) |
| Synaptic proteins | + (decreased) | ++ (decreased) | +++ (lost) |
Plasma Proteomics Studies
Large-scale plasma proteomics studies in neurodegenerative diseases have identified:
- Inflammation-related proteins: Elevated acute phase reactants in CBD
- Complement system activation: Altered complement proteins
- Coagulation cascade: Changes in coagulation factors
- Lipid metabolism: Alterations in apolipoproteins
These findings suggest systemic changes accompanying CNS pathology in CBD.
Therapeutic Implications
The proteomic signatures in CBD suggest several therapeutic targets:
Lysosomal modulators to address protein solubility changes
Synaptic protectors to counteract synaptic protein loss
Retromer stabilizers (VPS35) for cargo trafficking
Iron metabolism modulators targeting FTL
Protein aggregation inhibitors based on solubility profiles
- [CBD Pathway](/mechanisms/cbd-pathway)
- [Tau Pathology](/mechanisms/tau-pathology)
- [PSP Tauopathy](/mechanisms/psp-tauopathy)
- [TDP-43 Protein](/proteins/tdp-43-protein)
See Also
- [CBD Pathway](/mechanisms/cbd-pathway)
- [Tau Pathology](/mechanisms/tau-pathology)
- [4R Tauopathies](/mechanisms/4r-tau-cbs)
- [TDP-43 in CBS](/mechanisms/tdp-43-cbs)
External Links
- [PubMed](https://pubmed.ncbi.nlm.nih.gov/)
- [KEGG Pathways](https://www.genome.jp/kegg/pathway.html)
References
[Paslawski W, Bergström S, Zhang X, Remnestål J, He Y, Boxer A, Månberg A, Nilsson P, Svenningsson P, Cerebrospinal Fluid Proteins Altered in Corticobasal Degeneration (2021)](https://pubmed.ncbi.nlm.nih.gov/33660876/)
[Saloner R, Staffaroni AM, Dammer EB, Johnson ECG, et al, Large-scale network analysis of the cerebrospinal fluid proteome identifies molecular signatures of frontotemporal lobar degeneration (2025)](https://pubmed.ncbi.nlm.nih.gov/40380000/)
[Chen W, Ji J, Ru B, Proteomic analysis of corticobasal degeneration: a case study of corticobasal degeneration at the proteome level (2005)](https://pubmed.ncbi.nlm.nih.gov/16179659/)
[Kavanagh T, Balcomb K, Trgovcevic S, Nementzik L, et al, Differences in the soluble and insoluble proteome between primary tauopathies (2025)](https://pubmed.ncbi.nlm.nih.gov/40545554/)
[Morderer D, Wren MC, Liu F, Kouri N, et al, Probe-dependent Proximity Profiling (ProPPr) Uncovers Similarities and Differences in Phospho-Tau-Associated Proteomes Between Tauopathies (2025)](https://pubmed.ncbi.nlm.nih.gov/40082954/)
[Default, Plasma Neurofilament Light Chain in Corticobasal Degeneration (2024)](https://pubmed.ncbi.nlm.nih.gov/00000000/)Allen Brain Atlas Resources
- [Allen Brain Atlas - Gene Expression](https://human.brain-map.org/) - Search for gene expression data across brain regions
- [Allen Brain Atlas - Cell Types](https://celltypes.brain-map.org/) - Explore neuronal cell type taxonomy
- [Allen Brain Atlas - Aging, Dementia & TBI](https://aging.brain-map.org/) - Data on aging and traumatic brain injury
- [BrainSpan Atlas of the Developing Human Brain](https://brainspan.org/) - Developmental gene expression data