TNFRSF1A Gene

TNFRSF1A (TNF Receptor 1)

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">TNFRSF1A Gene</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>TNFRSF1A</td>
</tr>
<tr>
<td class="label">Gene Name</td>
<td>TNF Receptor Superfamily Member 1A</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>7132</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>P19438</td>
</tr>
<tr>
<td class="label">Aliases</td>
<td>TNFR1, TNF-R1, p55, p60</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>12p13.31</td>
</tr>
<tr>
<td class="label">Protein Length</td>
<td>455 amino acids</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~55 kDa</td>
</tr>
<tr>
<td class="label">Pathway</td>
<td>Primary Mediator</td>
</tr>
<tr>
<td class="label">NF-κB</td>
<td>IKK complex</td>
</tr>
<tr>
<td class="label">MAPK</td>
<td>MAPKKK cascade</td>
</tr>
<tr>
<td class="label">Apoptosis</td>
<td>FADD/Caspase-8</td>
</tr>
<tr>
<td class="label">Necroptosis</td>
<td>RIPK1/RIPK3/MLKL</td>
</tr>
<tr>
<td class="label">Oxidative stress</td>
<td>NADPH oxidase</td>
</tr>
<tr>
<td class="label">Trial</td>
<td>Agent</td>
</tr>
<tr>
<td class="label">Phase 2</td>
<td>Etanercept</td>
</tr>
<tr>
<td class="label">Phase 1/2</td>
<td>infliximab</td>
</tr>
<tr>
<td class="label">Phase 1</td>
<td>XENPOzyme</td>
</tr

TNFRSF1A (TNF Receptor 1)

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">TNFRSF1A Gene</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>TNFRSF1A</td>
</tr>
<tr>
<td class="label">Gene Name</td>
<td>TNF Receptor Superfamily Member 1A</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>7132</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>P19438</td>
</tr>
<tr>
<td class="label">Aliases</td>
<td>TNFR1, TNF-R1, p55, p60</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>12p13.31</td>
</tr>
<tr>
<td class="label">Protein Length</td>
<td>455 amino acids</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~55 kDa</td>
</tr>
<tr>
<td class="label">Pathway</td>
<td>Primary Mediator</td>
</tr>
<tr>
<td class="label">NF-κB</td>
<td>IKK complex</td>
</tr>
<tr>
<td class="label">MAPK</td>
<td>MAPKKK cascade</td>
</tr>
<tr>
<td class="label">Apoptosis</td>
<td>FADD/Caspase-8</td>
</tr>
<tr>
<td class="label">Necroptosis</td>
<td>RIPK1/RIPK3/MLKL</td>
</tr>
<tr>
<td class="label">Oxidative stress</td>
<td>NADPH oxidase</td>
</tr>
<tr>
<td class="label">Trial</td>
<td>Agent</td>
</tr>
<tr>
<td class="label">Phase 2</td>
<td>Etanercept</td>
</tr>
<tr>
<td class="label">Phase 1/2</td>
<td>infliximab</td>
</tr>
<tr>
<td class="label">Phase 1</td>
<td>XENPOzyme</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/anxiety" style="color:#ef9a9a">Anxiety</a>, <a href="/wiki/autoimmune" style="color:#ef9a9a">Autoimmune</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">161 edges</a></td>
</tr>
</table>

Pathway Diagram

Overview

TNFRSF1A (Tumor Necrosis Factor Receptor Superfamily Member 1A), commonly known as TNFR1 or p55, is a member of the tumor necrosis factor receptor superfamily. It is a type I transmembrane receptor that plays critical roles in inflammation, cell survival, and apoptosis. TNFR1 is one of the primary receptors for tumor necrosis factor-alpha (TNF-α), a key pro-inflammatory cytokine implicated in numerous neurodegenerative diseases. The receptor is widely expressed throughout the nervous system, including in neurons, astrocytes, microglia, and oligodendrocytes. This page covers the gene's molecular characteristics, signaling mechanisms, disease associations, and therapeutic implications.

Gene Overview

The TNFRSF1A gene consists of 10 exons and encodes a type I transmembrane protein with an extracellular domain containing four cysteine-rich domains (CRDs), a transmembrane helix, and an intracellular death domain. The death domain enables recruitment of adaptor proteins and activation of both pro-inflammatory and pro-apoptotic signaling pathways.

Structure

Extracellular Domain

The extracellular portion of TNFR1 contains four cysteine-rich domains (CRDs) that mediate ligand binding. TNF-α binds to the CRD2 and CRD3 regions with high affinity. The extracellular domain can be proteolytically cleaved to generate a soluble receptor form (sTNFR1) that can act as a decoy, sequestering TNF-α and preventing receptor activation.

Transmembrane Domain

A single transmembrane helix anchors TNFR1 in the cell membrane. This domain is essential for proper receptor clustering and signal transduction.

Intracellular Death Domain

The cytoplasmic death domain is critical for TNFR1's pro-apoptotic signaling functions. It recruits adaptor proteins including TRADD, FADD, and TRAF2, which determine whether the receptor triggers inflammatory or apoptotic responses.

Signaling Pathways

TNFR1 activates multiple downstream signaling cascades, with the outcome depending on cellular context and available adaptor proteins.

NF-κB Signaling Pathway

TNF-α binding --> TNFR1 trimerization --> TRAF2/5 recruitment --> NIK activation

NF-κB activation is the predominant signaling outcome of TNFR1 activation in most cell types. This pathway drives expression of pro-inflammatory cytokines, chemokines, adhesion molecules, and anti-apoptotic proteins. The NF-κB response is generally protective in the short term but can become pathological when chronically activated.

MAPK Pathways

TNFR1 also activates mitogen-activated protein kinase (MAPK) pathways:

• JNK pathway: Leads to AP-1 activation and can promote apoptosis
• p38 pathway: Contributes to stress response and inflammation
• ERK pathway: Can promote cell survival or proliferation depending on context

Apoptosis Pathway

When NF-κB signaling is inhibited or overwhelmed, TNFR1 can trigger apoptosis:

TNF-α binding --> TRADD recruitment --> FADD recruitment --> Caspase-8 activation

The death domain recruits TRADD, which in turn recruits FADD and caspase-8 to form the DISC (Death-Inducing Signaling Complex). Caspase-8 then activates the executioner caspase cascade.

Alternative Signaling

TNFR1 can also signal through:

• Ceramide production via acidic sphingomyelinase activation
• Reactive oxygen species (ROS) generation
• Calcium signaling

Role in Neurodegeneration

Alzheimer's Disease

TNFR1 plays a significant role in Alzheimer's disease pathogenesis through multiple mechanisms[@chen2019]:

Neuroinflammation: TNFR1 is a primary mediator of TNF-α-induced neuroinflammation in AD. The receptor activates NF-κB in microglia and astrocytes, leading to production of additional pro-inflammatory cytokines, creating a self-perpetuating inflammatory cycle.

Amyloid-beta Interaction: Aβ oligomers potentiate TNFR1 signaling and downstream inflammatory responses[@he2020]. TNFR1 activation can also increase APP expression and Aβ production, creating a vicious cycle between amyloid pathology and neuroinflammation.

Synaptic Dysfunction: TNFR1 activation contributes to synaptic loss and dysfunction in AD models[@yshid2018]. TNF-α signaling through TNFR1 can cause spine elimination and impair synaptic plasticity in the hippocampus.

Neuronal Death: In advanced disease stages, TNFR1 can contribute to neuronal apoptosis, particularly when cellular protective mechanisms are compromised.

Expression Changes: TNFR1 expression is elevated in AD brain tissue, particularly in regions with high amyloid burden and neurofibrillary pathology[@decourt2017].

Parkinson's Disease

In Parkinson's disease, TNFR1 contributes to dopaminergic neuron loss and neuroinflammation[@calleja2017]:

Dopaminergic Neuron Vulnerability: TNFR1-mediated signaling contributes to the selective vulnerability of substantia nigra dopaminergic neurons. The receptor is expressed at high levels in these neurons and responds to elevated TNF-α in the PD brain.

Microglial Activation: TNFR1 on microglia drives pro-inflammatory responses that damage nearby neurons. Activated microglia release additional TNF-α, amplifying the inflammatory cascade.

Age-Related Susceptibility: TNFR1 signaling contributes to age-related vulnerability of dopaminergic neurons[@mcglasson2019], which may explain the late-onset nature of sporadic PD.

Blood-Brain Barrier Dysfunction: TNFR1 contributes to BBB dysfunction in PD, increasing peripheral immune cell infiltration into the brain.

Amyotrophic Lateral Sclerosis (ALS)

TNFR1 is implicated in ALS pathogenesis through multiple mechanisms[@olszewski2019]:

Motor Neuron Death: TNFR1 contributes to TNF-α-mediated toxicity in motor neurons. The receptor can trigger both apoptotic and necroptotic cell death pathways.

Glial Activation: Activation of TNFR1 in astrocytes and microglia promotes neuroinflammatory responses that are toxic to motor neurons.

Neuromuscular Junction Denervation: TNFR1 signaling contributes to the process of neuromuscular junction denervation in ALS models.

SOD1 Models: TNFR1 is elevated in SOD1 transgenic mouse models of ALS and contributes to disease progression.

Multiple Sclerosis

In multiple sclerosis and its animal model EAE, TNFR1 plays a central role in demyelination[@kaiser2017]:

Oligodendrocyte Death: TNFR1 activation directly contributes to oligodendrocyte death through apoptotic mechanisms.

Immune Cell Infiltration: TNFR1 on endothelial cells promotes expression of adhesion molecules that facilitate immune cell trafficking into the CNS.

Demyelination: TNFR1 signaling in myelin-producing cells contributes to myelin damage and loss.

Ischemic Stroke

Following cerebral ischemia, TNFR1 contributes to secondary brain injury[@pross2018]:

• TNFR1 activation in the penumbra promotes inflammatory responses
• Contributes to delayed neuronal death
• Soluble TNFR1 levels in blood correlate with stroke outcomes
• TNFR1 blockade can reduce infarct size in experimental models

Traumatic Brain Injury

TNFR1 signaling contributes to secondary injury following TBI[@prokop2019]:

• Exacerbates neuroinflammation
• Contributes to blood-brain barrier disruption
• Promotes neuronal apoptosis
• Inhibition improves functional outcomes in experimental models

Expression Pattern

Brain Expression

TNFR1 is expressed throughout the central nervous system:

• Cerebral Cortex: High expression in pyramidal neurons
• Hippocampus: Expression in CA1-CA3 neurons and dentate gyrus
• Basal Ganglia: High expression in striatum and substantia nigra
• Cerebellum: Expression in Purkinje cells
• Spinal Cord: Motor neurons and interneurons

Cell Type Expression

• Neurons: Express TNFR1 at moderate levels
• Astrocytes: Express TNFR1, respond to TNF-α
• Microglia: High expression, primary inflammatory responders
• Oligodendrocytes: Express TNFR1, vulnerable to TNFR1-mediated death
• Endothelial cells: Express TNFR1, regulate BBB function

Therapeutic Implications

TNFR1 as a Therapeutic Target

Targeting TNFR1 represents a strategy for treating neurodegenerative diseases characterized by neuroinflammation:

Challenges

• TNF-α has both beneficial and harmful effects—global blockade may be detrimental
• TNFR2 often has protective functions—selective TNFR1 inhibition may be preferred
• Timing of intervention is critical for efficacy

See Also

• [TNF Gene](/genes/tnf) - Tumor necrosis factor
• [TNFRSF1B Gene](/genes/tnfr2) - TNF receptor 2 (TNFR2)
• [NF-κB Signaling](/entities/nf-kb)
• [Neuroinflammation Mechanisms](/mechanisms/neuroinflammation-pathway)
• [Microglial Activation](/cell-types/microglia)
• [Apoptosis Pathways](/mechanisms/apoptosis)

Structural Biology of TNFR1

Crystal Structure

The extracellular domain of TNFR1 has been crystallized and reveals a pre-formed ligand-binding domain that undergoes conformational changes upon TNF-α engagement[@banks2018]. The four cysteine-rich domains (CRDs) form a rigid structure that contacts TNF-α trimers at the CRD2-CRD3 interface, creating a high-affinity interaction with dissociation constants in the picomolar range.

Receptor Oligomerization

TNFR1 signaling is regulated by oligomeric state:

• [Monomeric receptors*: Low signaling capacity](/genes/gnal)
• [Pre-associated trimers*: Higher-order assemblies exist even without ligand](/genes/th)
• [Cluster formation*: TNF](/entities/tnf)R1 clusters at the cell surface upon ligand binding

Death Domain Structure

The intracellular death domain adopts a canonical six-helix bundle fold that recruits adaptor proteins through homotypic interactions. Mutations in the death domain can abolish signaling or cause constitutive activation, depending on the specific residues affected.

Signaling Complexity

Canonical vs. Alternative Pathways

TNFR1 activates multiple downstream pathways beyond NF-κB and MAPK:

Signalosome Formation

Upon ligand binding, TNFR1 recruits multiple adaptor proteins:

The composition of the TNFR1 signalosome determines downstream outcomes.

Cross-Talk with Other Receptors

TNFR1 signaling intersects with numerous other pathways:

• IL-1R signaling: Synergistic inflammation
• TLR pathways: Shared downstream effectors
• Integrin signaling: Cell adhesion effects
• Growth factor receptors: Survival vs. death decisions

TNFR1 in Specific Brain Regions

Substantia Nigra

TNFR1 is highly expressed in dopaminergic neurons of the substantia nigra pars compacta[@mcglasson2019]:

• These neurons show increased TNFR1 in PD
• TNF-α levels are elevated in the nigrostriatal pathway
• TNFR1-mediated inflammation contributes to neuronal death

Hippocampus

In the hippocampus, TNFR1 regulates:

• Synaptic plasticity mechanisms
• Memory consolidation processes
• Adult neurogenesis

Cerebral Cortex

Cortical neurons express TNFR1 at moderate levels:

• Pyramidal neurons are particularly vulnerable
• TNFR1 contributes to cortical atrophy in neurodegeneration
• Activity-dependent TNF-α release affects circuit function

Microglia

Microglial TNFR1 is a major driver of neuroinflammation:

• Constitutively expressed at low levels
• Rapidly upregulated in response to injury
• Controls cytokine cascade amplification

Therapeutic Targeting Strategies

Small Molecule Inhibitors

Several classes of TNFR1 inhibitors are in development:

Clinical Trials

Historical trials targeting TNF signaling in neurodegeneration:

Challenges in CNS Drug Delivery

Targeting TNFR1 in the brain faces significant obstacles:

• Blood-brain barrier penetration
• Peripheral vs. central compartment effects
• Timing of intervention (chronic vs. acute)
• Patient stratification based on inflammatory markers

Biomarker Development

Genetic Markers

SLC4A4 polymorphisms may influence TNFR1 function:

• Certain variants associate with disease severity
• Haplotypes affect expression levels
• Pharmacogenomic implications for therapy

Protein Biomarkers

Circulating TNFR1 levels serve as biomarkers:

• Soluble TNFR1 (sTNFR1): Shed from cell surface
• CSF TNFR1: Reflects CNS inflammation
• Correlation with progression: Higher levels = faster decline

Imaging Biomarkers

PET ligands targeting:

• TSPO ( translocator protein) for microglial activation
• Direct TNFR1 imaging remains challenging
• Downstream inflammatory markers

TNFR1 in Aging

Aging upregulates TNFR1 signaling in the brain:

• Increased basal TNF-α production
• Heightened receptor sensitivity
• Impaired negative feedback mechanisms
• Contributes to age-related neurodegeneration

TNFR1 and Proteinopathies

Alpha-Synuclein Interaction

TNF-α/TNFR1 signaling affects α-synuclein pathology:

• Increases SNCA gene expression
• Promotes aggregation
• Enhances propagation

Tau Phosphorylation

TNFR1-mediated pathways activate kinases:

• GSK-3β activation via NF-κB
• CDK5 involvement
• Contributes to tau pathology in AD

Amyloid Processing

TNFR1 influences APP processing:

• NF-κB activation increases BACE1 expression
• Enhances amyloidogenic cleavage
• Creates feed-forward loop with Aβ

Research Tools and Models

Mouse Models

Genetic models for studying TNFR1:

• Tnfr1a knockout mice: Constitutive deletion
• Conditional knockouts: Brain-specific deletion
• Humanized mice: Express human TNFR1

Cellular Models

• iPSC neurons: Patient-derived with TNFR1 variants
• Microglia cultures: Primary and immortalized lines
• Organoid systems: 3D brain models

Pharmacological Tools

• TNF-α neutralizing antibodies: Infliximab, adalimumab
• Fusion proteins: Etanercept (TNFR2-Fc)
• Selective inhibitors: XENPOzyme (phase 1)
• RIPK1 inhibitors: GSK2982772

Conclusions and Future Directions

TNFR1 represents a critical nexus between neuroinflammation and neurodegeneration. Its pleiotropic signaling outputs—spanning survival, inflammation, and cell death—make it both a compelling therapeutic target and a complex one. The challenge lies in selectively inhibiting harmful TNFR1 signaling while preserving the protective functions of TNF-α signaling through TNFR2 and other receptors.

Future research directions include:

• Development of brain-penetrant TNFR1-selective inhibitors
• Identification of patient subgroups with elevated TNFR1 signaling
• Combination therapies targeting multiple nodes of the neuroinflammatory cascade
• Timing optimization for intervention in disease progression

Pathway Diagram

The following diagram shows the key molecular relationships involving TNFRSF1A Gene discovered through SciDEX knowledge graph analysis: