Necroptosis In Neurodegeneration plays an important role in the study of neurodegenerative diseases. This page provides comprehensive information about this topic, including its mechanisms, significance in disease processes, and therapeutic implications.
Necroptosis In Neurodegeneration is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
membrane rupture and release of intracellular contents (damage-associated molecular patterns, or DAMPs), triggering robust [neuroinflammation[/mechanisms/[neuroinflammation[/mechanisms/[neuroinflammation[/mechanisms/[neuroinflammation--TEMP--/mechanisms)--FIX--. [necroptosis[/entities/[necroptosis[/entities/[necroptosis[/entities/[necroptosis--TEMP--/entities)--FIX-- was first
characterized in the early 2000s as a caspase-independent programmed cell death pathway and has since been recognized as a significant contributor to neuronal loss and
neuroinflammation in [Alzheimer's disease[/diseases/[alzheimers[/diseases/[alzheimers[/diseases/[alzheimers--TEMP--/diseases)--FIX--, [Parkinson's disease[/diseases/[parkinsons[/diseases/[parkinsons[/diseases/[parkinsons--TEMP--/diseases)--FIX--, [amyotrophic lateral sclerosis[/diseases/[als[/diseases/[als[/diseases/[als--TEMP--/diseases)--FIX--, [multiple sclerosis[/diseases/[multiple-sclerosis[/diseases/[multiple-sclerosis[/diseases/[multiple-sclerosis--TEMP--/diseases)--FIX--, and other [neurodegenerative conditions]. The
RIPK1-RIPK3-MLKL signaling axis has emerged as a promising therapeutic target, with several small molecule RIPK1 inhibitors advancing to clinical trials.
[necroptosis[/entities/[necroptosis[/entities/[necroptosis[/entities/[necroptosis--TEMP--/entities)--FIX-- is activated when death receptor signaling fails to engage the apoptotic pathway, typically due to caspase-8 inhibition or deficiency:
Initiation: Death receptors (TNFR1, Fas, TRAIL-R) or pathogen recognition receptors (TLR3, [TLR4[/entities/[tlr4[/entities/[tlr4[/entities/[tlr4--TEMP--/entities)--FIX--, ZBP1) transmit death signals. When TNF-α binds TNFR1, complex I forms at the receptor containing TRADD, TRAF2, cIAP1/2, and RIPK1, normally promoting [NF-κB[/entities/[nf-kb[/entities/[nf-kb[/entities/[nf-kb--TEMP--/entities)--FIX---mediated survival signaling ([Degterev et al., 2005](https://doi.org/10.1038/ncomms6888.
Complex IIb/Necrosome formation: When caspase-8 is inhibited, depleted, or overwhelmed, RIPK1 autophosphorylates at Ser166 and recruits RIPK3 through RHIM (RIP homotypic interaction motif) domain interactions. RIPK1 and RIPK3 form an amyloid-like signaling complex called the necrosome (Li et al., 2012).
MLKL phosphorylation: RIPK3 phosphorylates MLKL at Thr357 and Ser358 (human) or Ser345 (mouse), triggering a conformational change that exposes the N-terminal 4-helix bundle domain (Sun et al., 2012).
Membrane permeabilization: Phosphorylated MLKL oligomerizes and translocates to the plasma membrane, where it inserts into the lipid bilayer and forms pores, leading to ion influx (Ca²⁺, Na⁺), osmotic swelling, and membrane rupture (Wang et al., 2014).
DAMP release: Ruptured cells release intracellular contents including HMGB1, ATP, IL-33, mtDNA, and other DAMPs that activate [innate immune signaling] through pattern recognition receptors on [microglia[/cell-types/[microglia[/cell-types/[microglia[/cell-types/[microglia--TEMP--/cell-types)--FIX-- and a kinase (pro-death). Only the kinase activity of RIPK1 promotes necroptosis.
[necroptosis[/entities/[necroptosis[/entities/[necroptosis[/entities/[necroptosis--TEMP--/entities)--FIX-- can also be activated independently of RIPK1 through:
ZBP1 (DAI): Detects Z-form nucleic acids (Z-DNA/Z-RNA) and directly activates RIPK3 via RHIM domain interaction. This pathway is relevant in viral infections and may contribute to neurodegeneration through endogenous retroelement activation ([Jiao et al., 2020](https://doi.org/10.1038/s41586-020-2649-2.
TRIF: The TLR3/[TLR4[/entities/[tlr4[/entities/[tlr4[/entities/[tlr4--TEMP--/entities)--FIX-- adaptor protein TRIF can directly engage RIPK3 via its RHIM domain, linking innate immune sensing to necroptosis without requiring RIPK1.
Evidence for necroptosis in [Alzheimer's disease[/diseases/[alzheimers[/diseases/[alzheimers[/diseases/[alzheimers--TEMP--/diseases)--FIX-- has grown substantially:
Postmortem tissue: RIPK1, RIPK3, and MLKL protein levels are elevated 2-3 fold in hippocampi of AD patients compared to age-matched controls. RIPK1 colocalizes with RIPK3 and MLKL in [neurons[/entities/[neurons[/entities/[neurons[/entities/[neurons--TEMP--/entities)--FIX-- with high levels of phosphorylated tau], and expression levels correlate with Braak staging ([Bhatt et al., 2024](https://doi.org/10.1007/s00401-024-02650-7.
Inverse correlation with cognition: RIPK1 levels are inversely correlated with brain weight and cognitive performance scores, suggesting that necroptotic activation drives both neuronal loss and cognitive decline.
[Amyloid]-β-driven necroptosis: [Aβ[/entities/[amyloid-beta[/entities/[amyloid-beta[/entities/[amyloid-beta--TEMP--/entities)--FIX-- oligomers activate TNF-α signaling in [neurons[/entities/[neurons[/entities/[neurons[/entities/[neurons--TEMP--/entities)--FIX-- and [microglia[/cell-types/[microglia[/cell-types/[microglia[/cell-types/[microglia--TEMP--/cell-types)--FIX--/cell-types/microglia[microglia, promoting RIPK1-dependent necroptosis. [Amyloid plaques] are surrounded by dystrophic neurites with elevated RIPK1 and phospho-MLKL ([Caccamo et al., 2017)](https://doi.org/10.1038/nn.4608.
TNF-α-dependent pathway: In AD, TNF-α released by activated [microglia/Bhatt et al., 2024)](https://doi.org/10.1007/s00401-024-02650-7.
RIPK1 kinase activity: Increased RIPK1 kinase activity in AD brain tissue promotes M1 microglial polarization and pro-inflammatory marker expression, amplifying the neuroinflammatory cascade.
In [Parkinson's disease[/diseases/[parkinsons[/diseases/[parkinsons[/diseases/[parkinsons--TEMP--/diseases)--FIX--, necroptosis contributes to dopaminergic neuron loss:
MPTP model: In the MPTP mouse model of PD, RIPK1, RIPK3, and MLKL are upregulated in the substantia nigra. RIPK3 knockout or MLKL inhibition attenuates dopaminergic neuron death.
α-Synuclein and necroptosis: Aggregated [α-synuclein/proteins/alpha activates microglial TLR2, triggering TNF-α release and subsequent RIPK1-dependent necroptosis in neighboring [neurons[/entities/[neurons[/entities/[neurons[/entities/[neurons--TEMP--/entities)--FIX--.
Exercise-mediated protection: Rotarod training in MPTP-treated mice significantly decreases MLKL expression and phosphorylation of RIPK1 and RIPK3, suggesting exercise may be neuroprotective partly through necroptosis suppression (Zhang et al., 2025).
[ALS[/diseases/[als[/diseases/[als[/diseases/[als--TEMP--/diseases)--FIX-- shows significant involvement of necroptosis:
Optineurin mutations: Loss-of-function mutations in optineurin (OPTN), a cause of familial ALS, sensitize motor [neurons[/entities/[neurons[/entities/[neurons[/entities/[neurons--TEMP--/entities)--FIX-- to TNF-α-induced necroptosis by impairing RIPK1 ubiquitylation.
SOD1 mutant models: In SOD1-G93A transgenic mice, RIPK1 and RIPK3 are progressively upregulated in the spinal cord, and RIPK1 inhibition delays disease onset and extends survival.
[TDP-43[/entities/[tdp-43[/entities/[tdp-43[/entities/[tdp-43--TEMP--/entities)--FIX-- and inflammation: [TDP-43[/entities/[tdp-43[/entities/[tdp-43[/entities/[tdp-43--TEMP--/entities)--FIX-- pathology promotes microglial activation and TNF-α release, creating a pro-necroptotic environment in the motor [cortex[/brain-regions/[cortex[/brain-regions/[cortex[/brain-regions/[cortex--TEMP--/brain-regions)--FIX-- and spinal cord.
Clinical trial (SAR443820): Sanofi/Denali tested the brain-penetrant RIPK1 inhibitor SAR443820 (DNL788) in a Phase 2 ALS trial, but it did not meet the primary endpoint of change in ALSFRS-R (Sanofi, 2024.
In [multiple sclerosis[/diseases/[multiple-sclerosis[/diseases/[multiple-sclerosis[/diseases/[multiple-sclerosis--TEMP--/diseases)--FIX--, necroptosis drives both inflammatory demyelination and axonal damage:
Oligodendrocyte death: TNF-α released by infiltrating immune cells triggers necroptotic death of oligodendrocytes, contributing to demyelination.
Microglial necroptosis: Necroptotic [microglia release pro-inflammatory DAMPs that recruit additional immune cells, amplifying CNS inflammation.
RIPK1 in MS lesions: Active MS lesions show elevated RIPK1 and phospho-MLKL expression in both [neurons[/entities/[neurons[/entities/[neurons[/entities/[neurons--TEMP--/entities)--FIX-- and oligodendrocytes.
Clinical trial (SAR443820): Sanofi tested SAR443820 in a Phase 2 trial for relapsing and progressive MS (K2 study) but discontinued the trial in October 2024 after it failed to meet primary endpoints.
[Huntington's disease[/mechanisms/[huntington-pathway[/mechanisms/[huntington-pathway[/mechanisms/[huntington-pathway--TEMP--/mechanisms)--FIX--: Mutant [huntingtin[/proteins/[huntingtin[/proteins/[huntingtin[/proteins/[huntingtin--TEMP--/proteins)--FIX--/proteins/huntingtin) sensitizes striatal [neurons[/entities/[neurons[/entities/[neurons[/entities/[neurons--TEMP--/entities)--FIX-- to TNF-α-induced necroptosis. RIPK1 and RIPK3 are upregulated in the caudate nucleus of HD patients.
[Frontotemporal Dementia (FTD)[/diseases/[ftd[/diseases/[ftd[/diseases/[ftd--TEMP--/diseases)--FIX--: GRN (progranulin) haploinsufficiency, a major cause of FTD, increases microglial production of TNF-α and sensitizes [neurons[/entities/[neurons[/entities/[neurons[/entities/[neurons--TEMP--/entities)--FIX-- to RIPK1-dependent cell death.
A critical feature of necroptosis in neurodegeneration is the feed-forward cycle between cell death and [neuroinflammation[/mechanisms/[neuroinflammation[/mechanisms/[neuroinflammation[/mechanisms/[neuroinflammation--TEMP--/mechanisms)--FIX--:
SAR443820 is a brain-penetrant, orally bioavailable RIPK1 inhibitor that was well-tolerated in healthy volunteers and showed target engagement in the CNS. Despite the setbacks in ALS and MS Phase 2 trials, the RIPK1 inhibitor pipeline continues to expand with over 10 companies developing 12+ therapeutic candidates ([RIPK1 pipeline review, 2025]https://trial.medpath.com/news/cdfb7fedc35ff719/ripk1-inhibitor-pipeline-shows-promise-despite-sanofi-setback-in-multiple-sclerosis)).
RIPK3 inhibitors: Selective RIPK3 kinase inhibitors are in preclinical development. A challenge is that RIPK3 inhibition can paradoxically trigger apoptosis in some cellular contexts.
MLKL inhibitors: Necrosulfonamide (NSA) binds human MLKL and blocks necroptosis execution. Selective, drug-like MLKL inhibitors are being developed for CNS applications.
Given the convergence of multiple cell death pathways in neurodegeneration, combination strategies targeting necroptosis alongside [ferroptosis[/mechanisms/[ferroptosis[/mechanisms/[ferroptosis[/mechanisms/[ferroptosis--TEMP--/mechanisms)--FIX-- or [excitotoxicity[/entities/[excitotoxicity[/entities/[excitotoxicity[/entities/[excitotoxicity--TEMP--/entities)--FIX-- may provide synergistic neuroprotection.
Autosis - Non-apoptotic cell death with autophagic features
[huntingtin[/proteins/[huntingtin[/proteins/[huntingtin[/proteins/[huntingtin--TEMP--/proteins)--FIX--/proteins/huntingtin)
[All Mechanisms[/[mechanisms[/[mechanisms[/[mechanisms[/[mechanisms[/[mechanisms[/mechanisms
The study of [necroptosis[/entities/[necroptosis[/entities/[necroptosis[/entities/[necroptosis--TEMP--/entities)--FIX-- In Neurodegeneration 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.
Necroptosis In Neurodegeneration plays an important role in the study of neurodegenerative diseases. This page provides comprehensive information about this topic, including its mechanisms, significance in disease processes, and therapeutic implications.
🔴 Low Confidence
| Dimension | Score |
|---|---|
| Supporting Studies | 11 references |
| Replication | 0% |
| Effect Sizes | 50% |
| Contradicting Evidence | 0% |
| Mechanistic Completeness | 50% |
Overall Confidence: 36%