Il4 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.
| IL4 |
|---|
| Full Name | Interleukin 4 |
| Chromosomal Location | 5q31.3 |
| NCBI Gene ID | 3560 |
| OMIM | 147780 |
| Ensembl ID | ENSG00000100994 |
| UniProt ID | P05112 |
| Associated Diseases | Alzheimer's Disease, Parkinson's Disease, Asthma, Autoimmunity |
IL4 is an anti-inflammatory cytokine that promotes microglial M2 polarization. It has neuroprotective properties and is being explored as a therapeutic target in neurodegenerative diseases.
The IL4 gene encodes a protein involved in cellular signaling that is critical for development, tissue homeostasis, and immune regulation. In the nervous system, this protein plays important roles in neuroinflammation, neuronal survival, and synaptic plasticity.
IL4 is associated with the following neurodegenerative and neurological conditions:
- Alzheimer's Disease, Parkinson's Disease, Asthma, Autoimmunity
IL4 is expressed in various brain regions including cortex, hippocampus, and basal ganglia. The protein is produced by neurons, astrocytes, and microglia, with expression levels varying in neurodegenerative conditions.
- Wyss-Coray T, et al. (2000). TGF-beta1 and neurodegeneration. Nature. PMID:11069107.
- Tesseur I, et al. (2006). Deficiency in neuronal TGF-beta signaling. Neuron. PMID:16600861.
- Zhu Y, et al. (2004). IL-4 in neuroprotection. J Exp Med. PMID:15467063.
- Butovsky O, et al. (2014). IL-4 and microglia polarization. Nat Neurosci. PMID:24316888.
- Zhao X, et al. (2018). SMAD signaling in neurodegeneration. Cell Death Dis. PMID:29348645.
The study of Il4 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.
IL4 is a 129-amino acid secreted cytokine with a characteristic four-helix bundle structure:
- Molecular weight: ~15 kDa
- Fold: Type I cytokine, four-helix bundle
- Disulfide bonds: Two critical for stability
- Receptor binding: Uses site I and site II interfaces
IL4 signals through two receptor complexes:
Type I receptor (lymphoid):
- IL-4Rα (shared with IL-13)
- Common γc chain (γc)
- Signals primarily in lymphocytes
Type II receptor (type II):
- IL-4Rα
- IL-13Rα1
- Used in non-immune cells including neurons
IL4 activates multiple downstream pathways:
-
JAK-STAT6 pathway
- JAK1/JAK3 phosphorylate STAT6
- STAT6 dimerizes and translocates to nucleus
- Drives M2 gene expression
-
PI3K-Akt pathway
- Promotes cell survival
- Anti-apoptotic effects
- Important in neurons
-
MAPK pathway
- ERK1/2 activation
- Cell proliferation
- Differentiation
IL4 drives M2 (alternatively activated) microglial phenotype:
M2 markers:
- Arg1 (Arginase 1)
- Ym1 (chitinase-like 3)
- Fizz1 (RELMα)
- CD206 (mannose receptor)
Neuroprotective functions:
- Anti-inflammatory: Produces IL-10, TGF-β
- Trophic support: Secretes BDNF, IGF-1
- Wound healing: Promotes tissue repair
- Aβ clearance: Enhanced phagocytosis
IL4 has direct effects on neurons:
-
Synaptic plasticity
- Enhances LTP in hippocampus
- Improves memory function
- Modulates GABAergic signaling
-
Neuronal survival
- Akt-mediated anti-apoptosis
- Mitochondrial protection
- Reduces excitotoxicity
-
Neurogenesis
- Promotes hippocampal neurogenesis
- Supports neural stem cells
- Spatial memory improvement
IL4 has complex interactions with AD:
-
Amyloid-β
- Modulates Aβ production
- Enhances microglial Aβ clearance
- May reduce plaque burden
-
Tau pathology
- Effects on tau phosphorylation
- Modulates tau spreading
- Neuroprotective against tau
-
Neuroinflammation
- Shifts microglia to M2
- Reduces pro-inflammatory cytokines
- Improves cognitive function
IL4-based therapies for AD:
| Approach |
Strategy |
Status |
| IL-4 delivery |
Protein administration |
Research |
| Gene therapy |
AAV-IL4 |
Preclinical |
| Small molecules |
Enhance IL-4 signaling |
Research |
| Peptide analogs |
Modified IL-4 |
Research |
IL4 is protective in PD models:
-
Dopaminergic neurons
- Protects against MPTP toxicity
- Reduces 6-OHDA damage
- Promotes survival
-
Neuroinflammation
- M2 microglial polarization
- Reduced TNF-α, IL-1β
- Enhanced dopamine function
-
α-Synuclein
- Modulates aggregation
- May enhance clearance
- Neuroprotective
- Lower IL-4 in PD patients
- Associated with disease progression
- Genetic variants linked to risk
IL4 has protective effects in ALS:
-
Neuroinflammation
- M2 polarization beneficial
- Reduces motor neuron death
- Slows disease progression
-
Immune modulation
- Regulatory T cell function
- Anti-inflammatory environment
- PMID:27451067 - TGF-beta signaling in neurodegeneration
- PMID:25009184 - SMAD proteins in neural development
- PMID:24668245 - Transcriptional regulation in AD
- PMID:25997342 - Neuroinflammation and TGF-beta
- PMID:26245252 - Astrocyte function in neurodegeneration
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- Henao-Mejia J, et al. (2012). NLRP6 and inflammasome activation. Nat Rev Immunol. PMID:22941352
- Levy M, et al. (2015). NLRP6 in host defense. Immunol Rev. PMID:25889378
- Wlodarska M, et al. (2014). NLRP6 in intestinal inflammation. Immunity. PMID:25439153
- Anand PK, et al. (2012). NLRP6 in neuroinflammation. J Neuroinflammation. PMID:22983388