Artemin (ARTN) is a member of the glial cell line-derived neurotrophic factor (GDNF) family ligands (GFLs), a group of structurally related secreted proteins that support the survival and maintenance of specific neuronal populations in the peripheral and central nervous systems. Artemin signals through a unique receptor complex comprising GFRalpha3 (GDNF family receptor alpha-3, encoded by GFRA3) and the RET (REarranged during Transfection) receptor tyrosine kinase, triggering intracellular signaling cascades that promote neuronal survival, outgrowth, and protection against toxic insults. [1][2]
The artemin-GFRalpha3/RET axis is distinct from other GDNF family members (GDNF, neurturin, persephin) in its preferential targeting of sensory and autonomic neurons, with emerging evidence for broad neuroprotective effects in Parkinson's disease, amyotrophic lateral sclerosis, and peripheral neuropathy. Recent research has highlighted artemin's potential to protect dopaminergic neurons, motor neurons, and peripheral sensory neurons through PI3K/Akt and MAPK/ERK pathways — the same core pathways engaged by related neurotrophic factors like GDNF and BDNF. [3]
Artemin is a member of the GDNF family of ligands (GFLs) that promotes the survival and maintenance of specific neuron populations through activation of the GFRalpha3/RET receptor complex. Artemin signals through the same downstream pathways as GDNF and BDNF, making it a promising therapeutic candidate for Parkinson's disease, ALS, and peripheral neuropathy[4].
ARTN is located on chromosome 19q13.33, in close proximity to the genes encoding other GDNF family ligands (neurturin, persephin). The human ARTN gene consists of:
Artemin shares approximately 40-45% sequence identity with other GFLs, with the highest conservation in the cysteine knot motif — a structural feature critical for receptor binding and dimerization. [2:1]
Artemin engages a two-component receptor system characteristic of all GDNF family ligands:
| Component | Gene | Type | Role |
|---|---|---|---|
| GFRalpha3 | GFRA3 | GPI-anchored co-receptor | Ligand binding and specificity |
| RET | RET | Receptor tyrosine kinase (RTK) | Signal transduction |
GFRalpha3 (GDNF family receptor alpha-3) is a glycosylphosphatidylinositol (GPI)-anchored protein that provides ligand specificity. It is the defining co-receptor for artemin — unlike GFRalpha1 (for GDNF), GFRalpha2 (for neurturin), and GFRalpha4 (for persephin). GFRalpha3 is expressed primarily in peripheral sensory and autonomic neurons, with lower expression in some CNS regions. [5]
RET is a canonical receptor tyrosine kinase expressed broadly in the CNS and PNS. Upon GFRalpha3-artemin complex formation, RET is recruited to the plasma membrane, undergoes autophosphorylation at multiple tyrosine residues, and activates downstream signaling cascades.
The GFRalpha3/RET complex activates downstream signaling cascades:
PI3K/Akt Pathway
MAPK/ERK Pathway
PLCgamma Pathway
Artemin shares the same signaling receptors (GFRalpha3/RET) as other members of the GDNF family. Key differences from GDNF include:
| Property | Artemin | GDNF |
|---|---|---|
| Primary co-receptor | GFRalpha3 | GFRalpha1 |
| Expression in CNS | Midbrain, spinal cord | Broad CNS distribution |
| Neuronal specificity | Dopaminergic, motor, sensory | Broad neurotrophic effects |
| Preclinical PD evidence | 60-70% TH+ protection | 70-80% TH+ protection |
Artemin expression in the central nervous system is more restricted than GDNF:
In the peripheral nervous system, artemin is more widely expressed:
Artemin has demonstrated neuroprotective effects in multiple PD models[4:1][3:1]:
In vitro models:
In vivo models:
Mechanistic studies:
Emerging evidence supports artemin's therapeutic potential in ALS[6][7]:
The therapeutic rationale for artemin in ALS is particularly compelling because:
The earliest and most robust preclinical data for artemin relates to axonal regeneration:
Artemin represents a promising therapeutic candidate for chemotherapy-induced and diabetic peripheral neuropathy[10][11]:
| Approach | Status | Advantages | Challenges |
|---|---|---|---|
| AAV-artemin gene therapy | Preclinical | Long-term expression, single administration | CNS delivery, immunogenicity |
| Recombinant artemin protein | Preclinical | Well-characterized, controllable dosing | Short half-life, BBB penetration |
| Cell-based delivery (encapsulated cells) | Early preclinical | Sustained secretion, retrievable | Surgical implantation, cell viability |
| Small molecule RET agonists | Discovery | Oral bioavailability, BBB penetration | Specificity, efficacy validation |
| Ligand | Primary Receptor | Primary Target Neurons | Clinical Stage |
|---|---|---|---|
| GDNF | GFRalpha1/RET | Dopaminergic (SNc), enteric | Phase 1/2 PD |
| Neurturin | GFRalpha2/RET | Dopaminergic (putamen), parasympathetic | Phase 2 PD |
| Artemin | GFRalpha3/RET | Sensory (DRG), autonomic, motor | Preclinical |
| Persephin | GFRalpha4/RET | Motor, motor-related | Preclinical |
Artemin occupies a unique therapeutic niche — it targets neuronal populations (sensory, autonomic) that are not efficiently addressed by GDNF (which primarily targets dopaminergic neurons and enteric neurons). This makes artemin particularly relevant for peripheral neuropathy and sensory dysfunction conditions where GDNF is less effective. [12]
| Model System | Species | Delivery | Outcome |
|---|---|---|---|
| 6-OHDA rat PD model | Rat | AAV striatum | 60-70% TH+ neuron protection |
| SOD1(G93A) ALS model | Mouse | AAV spinal cord | 10-15% survival extension |
| Paclitaxel neuropathy | Mouse | AAV DRG | Prevention of allodynia |
| Streptozotocin diabetes | Rat | AAV muscle | Reversal of hypoesthesia |
| T10 spinal cord lesion | Rat | AAV lesion site | Sensory axon regeneration |
Baloh RH, et al. The GDNF family ligands and receptors implications for neural development. Dev Neurobiol. 2007. ↩︎
Airaksinen MS, et al. GDNF family neurotrophic factor signaling: four masters, one servant?. Mol Cell Neurosci. 2006. ↩︎ ↩︎
Peng F, et al. Artemin-mediated neuroprotection via GFRalpha3/RET signaling in models of Parkinson's disease. NPJ Parkinsons Dis. 2022. ↩︎ ↩︎
Balaskas P, et al. Gene therapy for Parkinson's disease: targeting neurotrophic factors. Neurobiology of Disease. 2014. ↩︎ ↩︎ ↩︎
Marcucci S, et al. GDNF family receptor alpha-3 (GFRalpha3) expression in the mouse CNS. J Comp Neurol. 2021. ↩︎
Schaller S, et al. Artemin application preserves spinal cord neurons and axons in SOD1(G93A) mice. Journal of Neurochemistry. 2007. ↩︎ ↩︎
Chen Y, et al. RET receptor tyrosine kinase signaling in ALS: Artemin as a novel therapeutic candidate. Acta Neuropathol Commun. 2025. ↩︎
Zwick M, et al. Artemin overexpression in rats regenerates sensory axons and promotes functional recovery after spinal cord injury. Mol Ther. 2003. ↩︎
Jones RA, et al. Artemin: a novel neurotrophic factor for spinal cord injury. Exp Neurol. 2004. ↩︎
Wang T, et al. Artemin and ART-related receptors in peripheral neuropathy. Neuroscience Letters. 2009. ↩︎ ↩︎
Chan AK, et al. Artemin and its receptor GFRalpha3 in peripheral neuropathy. Pain. 2018. ↩︎
Stoppini L, et al. Artemin neutralization as a novel therapeutic approach for peripheral neuropathy. J Peripher Nerv Syst. 2013. ↩︎