CCL25 Gene

Overview

flowchart TD
    CCL25["CCL25"] -->|"biomarker for"| Ms["Ms"]
    CCL25["CCL25"] -->|"biomarker for"| Inflammation["Inflammation"]
    CCL25["CCL25"] -->|"associated with"| Depression["Depression"]
    CCL25["CCL25"] -->|"therapeutic target"| Tumor["Tumor"]
    CCL25["CCL25"] -->|"therapeutic target"| Autoimmune["Autoimmune"]
    CCL25["CCL25"] -->|"biomarker for"| Aging["Aging"]
    CCL25["CCL25"] -->|"associated with"| Neuroinflammation["Neuroinflammation"]
    CCL25["CCL25"] -->|"associated with"| Inflammation["Inflammation"]
    CCL25["CCL25"] -->|"biomarker for"| Alzheimer["Alzheimer"]
    CCL25["CCL25"] -->|"biomarker for"| Neurodegeneration["Neurodegeneration"]
    CCL25["CCL25"] -->|"biomarker for"| CXCL10["CXCL10"]
    CCL25["CCL25"] -->|"activates"| CX3CR1["CX3CR1"]
    CCL25["CCL25"] -->|"associated with"| CNP["CNP"]
    CCL25["CCL25"] -->|"associated with"| MMP1["MMP1"]
    style CCL25 fill:#4fc3f7,stroke:#333,color:#000

CCL25 (C-C Motif Chemokine Ligand 25), also known as Thymus Expressed Chemokine (TECK), is a chemokine originally identified in the thymus that plays crucial roles in T cell development and mucosal immunity. CCL25 binds exclusively to CCR9, making it a unique target for therapeutic modulation. In the nervous system, CCL25/CCR9 signaling has been implicated in neuroinflammation, gut-brain axis communication, and potentially in neurodegenerative diseases

Gene Overview

Function

CCL25 has distinct functions in immune development and homeostasis:

Immune System

• T cell development: Critical for thymocyte migration and T cell development in the thymus^{2CCL25 in T cell development (2002)2002 · DOI 10.4049/jimmunol.168.1.281Open reference}

• Gut homing: Guides α4β7+ T cells to intestinal lamina propria via CCR9

• Mucosal immunity: Important for immune surveillance of gastrointestinal tract

Nervous System

• Neuroinflammation: Modulates inflammatory responses in CNS

• Gut-brain axis: Potential pathway for gut-immune-brain communication

• Blood-brain barrier: May influence BBB function under inflammatory conditions

Receptor

CCL25 has a unique receptor profile:

• CCR9 (CC Chemokine Receptor 9): The sole receptor for CCL25

• Expression: High on small intestinal T cells, thymocytes, and some inflammatory cells

• Alternative: Can also bind to CCR9 splice variants

CCR9 Signaling

CCL25/CCR9 activates characteristic chemokine signaling^{3Chemokines and the homing of hematopoietic cells2005 · DOI 10.1016/j.blre.2005.04.001Open reference4CCR9 in neuroimmune communication and neuroinflammation2023 · DOI 10.1038/s41392-023-01432-5Open reference}:

1. Gαi signaling: Inhibition of adenylate cyclase

2. PLC-IP3 pathway: Calcium mobilization

3. PI3K/Akt pathway: Cell survival and migration

4. MAPK/ERK pathway: Cell activation and proliferation

5. Rho GTPases: Actin cytoskeleton reorganization

CCR9 Expression in Disease

CCR9 is over-expressed in several disease contexts^{5CCR9 in cancer metastasis2019 · DOI 10.1016/j.canlet.2019.02.038Open reference}:

• Inflammatory bowel disease

• Colorectal cancer metastasis

• Certain leukemias

• Autoimmune conditions

Signaling Pathways

CCL25/CCR9 activates characteristic chemokine signaling:

1. Gαi signaling: Inhibition of adenylate cyclase

2. PLC-IP3 pathway: Calcium mobilization

3. PI3K/Akt pathway: Cell survival and migration

4. MAPK/ERK pathway: Cell activation and proliferation

5. Rho GTPases: Actin cytoskeleton reorganization

CCL25/CCR9 in the Gut-Brain Axis

The CCL25/CCR9 axis plays a significant role in the gut-brain communication pathway, which has emerged as a critical factor in neurodegenerative disease pathogenesis^{6Gut microbiota-immune axis in Parkinson's disease2022 · DOI 10.1016/j.jneuroim.2022.577891Open reference}.

Gut-Associated Lymphoid Tissue (GALT)

• CCL25 is highly expressed in the small intestine, particularly in the crypt epithelium

• CCR9+ T cells home to the intestinal lamina propria under homeostatic conditions

• The intestinal immune system communicates with the CNS through multiple pathways:

  • Vagal afferent nerves

  • Circulating immune mediators

  • Microbial metabolites (short-chain fatty acids, bile acids)

  • Endocrine signaling

Microbial Modulation of CCL25/CCR9

• Gut microbiota can influence CCL25 expression in intestinal epithelial cells

• Dysbiosis alters CCR9+ T cell trafficking and may affect systemic inflammation

• Probiotic interventions may modulate CCL25/CCR9 axis in therapeutic contexts

Intestinal Permeability

• CCL25/CCR9 signaling affects tight junction integrity in intestinal epithelium

• Increased intestinal permeability (“leaky gut”) associated with neuroinflammation

• Potential for CCL25-targeted interventions to restore barrier function

Disease Associations

Neurodegenerative Diseases

Alzheimer’s Disease

In Alzheimer’s disease, the CCL25/CCR9 axis contributes to neuroinflammation through several mechanisms^{7Chemokines in Alzheimer's disease (2016)2016 · DOI 10.3233/JAD-160330Open reference8Neuroimmune cross-talk in Alzheimer's disease2015 · DOI 10.1038/nrn3880Open reference}:

• Amyloid-beta effects: Aβ peptides can induce CCL25 expression in astrocytes and microglia

• Microglial activation: CCR9 signaling modulates microglial phenotypic polarization

• T cell trafficking: Peripheral T cells expressing CCR9 may enter the CNS in AD

• Blood-brain barrier: CCL25 may affect BBB permeability through endothelial cell activation

Research has shown elevated CCL25 levels in cerebrospinal fluid of AD patients compared to controls, suggesting potential as a biomarker

Parkinson’s Disease

The CCL25/CCR9 axis is implicated in Parkinson’s disease through gut-brain axis mechanisms^{9Gut-brain axis and neurodegenerative diseases2020 · DOI 10.1016/j.jneuroim.2020.577271Open reference10Gut-brain axis and behavior2020 · DOI 10.1111/ncn3.12337Open reference2CCL25 in T cell development (2002)2002 · DOI 10.4049/jimmunol.168.1.281Open reference}0:

• Enteric nervous system: CCR9+ T cells accumulate in the gut in PD

• Alpha-synuclein propagation: Gut inflammation may accelerate synucleinopathy spread

• Dopaminergic neurons: CCL25 may directly affect survival of dopaminergic neurons

• Microbiota-gut-brain axis: CCL25 expression modulated by gut microbiome alterations

Multiple Sclerosis

CCL25 plays complex roles in multiple sclerosis^{2CCL25 in T cell development (2002)2002 · DOI 10.4049/jimmunol.168.1.281Open reference}1:

• T cell recruitment: CCR9+ T cells may traffic to CNS lesions

• Intestinal immune dysfunction: MS patients often exhibit gut immune abnormalities

• Therapeutic potential: CCR9 antagonists explored for MS treatment

• Remyelination: CCL25 may influence oligodendrocyte precursor cell function

Neuroinflammation

CCL25 participates in neuroinflammatory processes^{2CCL25 in T cell development (2002)2002 · DOI 10.4049/jimmunol.168.1.281Open reference}2^{2CCL25 in T cell development (2002)2002 · DOI 10.4049/jimmunol.168.1.281Open reference}3^{2CCL25 in T cell development (2002)2002 · DOI 10.4049/jimmunol.168.1.281Open reference}4^{2CCL25 in T cell development (2002)2002 · DOI 10.4049/jimmunol.168.1.281Open reference}5:

• Modulates T cell trafficking into CNS

• Influences blood-brain barrier permeability

• May interact with other chemokines in inflammatory cascades

• Potential role in autoimmune encephalitis

• Cytokine storm modulation in neuroinflammatory conditions

Other Conditions

• Inflammatory bowel disease (Crohn’s disease particularly)

• Celiac disease

• Type 1 diabetes

• Certain cancers (colorectal, pancreatic)

• HIV infection

• Graft-versus-host disease

Expression

CCL25 expression is tissue-specific:

Regulation of Expression

CCL25 expression is dynamically regulated:

• Inflammatory cytokines: TNF-α, IL-1β, and IFN-γ upregulate CCL25

• Microbial signals: TLR agonists can induce CCL25 expression

• Hormonal regulation: Estrogen may modulate CCL25 levels

• Epigenetic control: DNA methylation patterns affect CCL25 transcription

Therapeutic Potential

The CCL25/CCR9 axis is a therapeutic target with multiple intervention strategies^{2CCL25 in T cell development (2002)2002 · DOI 10.4049/jimmunol.168.1.281Open reference}6^{2CCL25 in T cell development (2002)2002 · DOI 10.4049/jimmunol.168.1.281Open reference}7^{2CCL25 in T cell development (2002)2002 · DOI 10.4049/jimmunol.168.1.281Open reference}8:

Therapeutic Strategies

1. CCR9 Antagonists: Small molecule inhibitors that block CCL25-CCR9 binding

2. CCL25 Neutralizing Antibodies: Monoclonal antibodies that sequester CCL25

3. Decoy Receptors: Soluble CCR9 extracellular domains that compete for ligand

4. RNAi-based Therapies: siRNA or antisense oligonucleotides targeting CCL25 or CCR9

Clinical Applications

The CCL25/CCR9 axis has been targeted in several clinical contexts^{2CCL25 in T cell development (2002)2002 · DOI 10.4049/jimmunol.168.1.281Open reference}9^{3Chemokines and the homing of hematopoietic cells2005 · DOI 10.1016/j.blre.2005.04.001Open reference}0:

• Inflammatory Bowel Disease: CCR9 antagonists in Phase I/II trials showed efficacy in Crohn’s disease

• Celiac Disease: CCL25-blocking strategies investigated for refractory disease

• Asthma: Investigated for eosinophilic airway inflammation

• Cancer Metastasis: CCR9 inhibition to prevent tumor spread, particularly in colorectal cancer

• Transplant: CCR9 blockade to prevent graft-versus-host disease

Drug Development Pipeline

Several CCR9-targeted agents have been developed^{3Chemokines and the homing of hematopoietic cells2005 · DOI 10.1016/j.blre.2005.04.001Open reference}1^{3Chemokines and the homing of hematopoietic cells2005 · DOI 10.1016/j.blre.2005.04.001Open reference}2:

Emerging Applications in Neurodegeneration

• Alzheimer’s disease: CCR9 antagonists may reduce neuroinflammation and Aβ-induced damage

• Parkinson’s disease: Modulation of gut-brain axis inflammation through CCL25 inhibition

• Multiple sclerosis: CCR9 blockade may reduce CNS-infiltrating T cells

• Amyotrophic lateral sclerosis: Potential for modulating inflammatory responses

Challenges and Considerations

• BBB penetration: Ensuring therapeutic agents reach CNS targets

• Homeostatic vs. inflammatory roles: Targeting CCL25 without disrupting normal immune function

• Biomarker development: Identifying patient subgroups most likely to benefit

• Combination therapies: Potential synergies with other immunomodulatory agents

Cross-References

• Parkinson’s Disease - Gut-brain axis

• Alzheimer’s Disease

• Neuroinflammation

• Chemokine Signaling

• Gut-Brain Axis

See Also

• Parkinson’s Disease

• Alzheimer’s Disease

• Neuroinflammation

• Chemokine Signaling

• Gut-Brain Axis

External Links

• NCBI Gene: 6374