CHI3L1 Gene
Introduction
<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">CHI3L1 Gene</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>CHI3L1</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Chitinase 3-Like 1</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>1q32.1</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>1116</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>P36222</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000133048</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/alzheimer" style="color:#ef9a9a">Alzheimer</a>, <a href="/wiki/amyotrophic-lateral-sclerosis" style="color:#ef9a9a">Amyotrophic Lateral Sclerosis</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">178 edges</a></td>
</tr>
</table>
Chi3L1 Gene is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Pathway Diagram
...CHI3L1 Gene
Introduction
<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">CHI3L1 Gene</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>CHI3L1</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Chitinase 3-Like 1</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>1q32.1</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>1116</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>P36222</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000133048</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/alzheimer" style="color:#ef9a9a">Alzheimer</a>, <a href="/wiki/amyotrophic-lateral-sclerosis" style="color:#ef9a9a">Amyotrophic Lateral Sclerosis</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">178 edges</a></td>
</tr>
</table>
Chi3L1 Gene is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Pathway Diagram
Mermaid diagram (expand to render)
Knowledge graph relationships for CHI3L1 (321 total edges in KG)
Overview
CHI3L1 (Chitinase 3-Like 1) is a secreted glycoprotein that serves as a biomarker for neuroinflammation in neurodegenerative diseases. Also known as YKL-40, it is produced by activated [microglia](/cell-types/microglia-neuroinflammation), [astrocytes](/entities/astrocytes), and macrophages in response to inflammatory stimuli. [@cell]
Normal Function
CHI3L1 is a member of the glycosyl hydrolase family 18 but lacks enzymatic activity. It functions as:
- Extracellular matrix remodeling - binds to chitin, heparin, and collagen
- Cell proliferation and differentiation - modulates growth factor signaling
- Inflammatory response regulator - enhances cytokine production by immune cells
- Microglial activation marker - indicates neuroinflammatory states
Disease Associations
Alzheimer's Disease
- Elevated CSF and plasma YKL-40 levels correlate with disease progression
- Associated with [tau](/proteins/tau) pathology and cognitive decline
- May predict conversion from MCI to AD
- Studied as a complementary biomarker to amyloid and [tau](/proteins/tau)
Parkinson's Disease
- Increased YKL-40 in CSF of PD patients
- Correlates with disease severity and motor symptoms
- Associated with neuroinflammatory processes in substantia nigra
Multiple Sclerosis
- Strong marker for microglial activation
- Associated with lesion load and disease progression
- Different from classical inflammatory markers
Amyotrophic Lateral Sclerosis
- Elevated in CSF and serum
- Correlates with disease progression rate
- May reflect non-neuronal (glial) involvement
Expression Pattern
- Brain: Highly expressed in [hippocampus](/brain-regions/hippocampus), [cortex](/brain-regions/cortex), and basal ganglia
- Cell Types: Primarily microglia and astrocytes
- Induction: Pro-inflammatory cytokines (IL-1β, TNF-α, IFN-γ)
Therapeutic Implications
YKL-40 as a therapeutic target:
- Anti-inflammatory strategies may reduce YKL-40-mediated inflammation
- Monoclonal antibodies against YKL-40 in development
- Biomarker utility for patient stratification and treatment monitoring
Key Publications
[YKL-40 in Alzheimer's disease](https://pubmed.gov/23467410) - Mathews et al., Neurology, 2013
[YKL-40 as neuroinflammation marker in Parkinson's disease](https://pubmed.gov/28761934) - Wu et al., J Neuroinflammation, 2017
[CSF YKL-40 in ALS patients](https://pubmed.gov/26961712) - Sjögren et al., Neurology, 2016
[YKL-40 in multiple sclerosis](https://pubmed.gov/22689767) - Cantó et al., Mult Scler, 2012
[YKL-40 and tau pathology](https://pubmed.gov/29348219) - Querol-Vilaseca et al., JAD, 2017Cross-Links
- [Alzheimer's Disease Biomarkers](/diseases/alzheimers-disease-biomarkers)
- [Parkinson's Disease Biomarkers](/biomarkers/parkinsons-disease-biomarkers)
- [Neuroinflammation Pathway](/mechanisms/neuroinflammation-pathway)
- [Microglia](/cell-types/microglia)
- [CSF Biomarkers](/biomarkers/csf-biomarkers)
Background
The study of Chi3L1 Gene 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.
See Also
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Amyloid Hypothesis](/mechanisms/amyloid-hypothesis)
- [Tau Pathology](/mechanisms/tau-pathology)
- [Parkinson's Disease](/diseases/parkinsons-disease)
- [Alpha-Synuclein](/mechanisms/alpha-synuclein)
External Links
- [NCBI Gene: CHI3L1](https://www.ncbi.nlm.nih.gov/gene/1116)
- [UniProt: P36222](https://www.uniprot.org/uniprot/P36222)
- [GeneCards: CHI3L1](https://www.genecards.org/cgi-bin/carddisp.pl?gene=CHI3L1)
Expression Pattern
CHI3L1/YKL-40 shows cell-type and region-specific expression:
- [Brain cells*: Primarily activated microglia and astrocytes](/cell-types/microglia)
- Peripheral immune cells: Macrophages, neutrophils
- [Brain regions*: Highest in hippocampus, basal ganglia, and white matter](/brain-regions)
- [Disease states*: Expression increases dramatically in neuroinflammatory conditions](/genes/nfl)
CSF and plasma YKL-40 levels provide information about ongoing neuroinflammatory processes in the central nervous system.
Molecular Mechanisms
Despite lacking enzymatic activity, CHI3L1 exerts multiple functions:
[@ecm]: ECM Remodeling: Binds to chitin, heparin, and various collagen types
[@cell]: Cell Signaling: Interacts with IL-13Rα2 to activate MAPK and PI3K/Akt pathways
[@cella]: Cell Migration: Promotes migration of macrophages and astrocytes
[@angiogenesis]: Angiogenesis: Induces endothelial cell proliferation and tube formation
[@inflammation]: Inflammation: Modulates cytokine production and immune cell activation
Cellular sources in the CNS:
- Microglia: Primary source in neurodegenerative diseases
- Astrocytes: Particularly in reactive astrocytes surrounding plaques
- Neurons: Limited expression, increases in stressed neurons
Therapeutic Implications
CHI3L1 as a biomarker and therapeutic target:
- Biomarker utility: YKL-40 levels correlate with disease progression
- Anti-YKL-40 antibodies: Being developed to neutralize YKL-40
- Small molecule inhibitors: Targeting IL-13Rα2 signaling
- Microglial modulation: Reducing CHI3L1-expressing microglia
Clinical applications:
- Prognostic biomarker in AD and PD
- Treatment response monitoring
- Disease progression tracking
Animal Models
- Chi3l1 knockout mice: Show altered inflammatory responses
- Transgenic overexpression: Develop enhanced neuroinflammation
- Mouse models of AD: YKL-40 correlates with plaque load
- PD models: Increased YKL-40 in substantia nigra
Research Directions
- Developing YKL-40-targeted therapeutics
- Understanding CHI3L1's protective vs. pathogenic roles
- Biomarker validation in large clinical cohorts
- Multi-analyte biomarker panels including YKL-40
References
Pathway Diagram
The following diagram shows the key molecular relationships involving CHI3L1 Gene discovered through SciDEX knowledge graph analysis:
Mermaid diagram (expand to render)