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Updated: Dec 26, 2025
Quantitative 3D In Silico Modeling q3DISM of Cerebral Amyloid-beta Phagocytosis in Rodent Models of Alzheimer's Disease
Published on: December 26, 2016
Early intraneuronal amyloid triggers neuron-derived inflammatory signaling in APP transgenic rats and human brain
Lindsay A Welikovitch1, Sonia Do Carmo2, Zsófia Maglóczky3
1Department of Neurology and Neurosurgery, McGill University, Montreal, QC H3G 1Y6, Canada.
Abstract:
Chronic inflammation during Alzheimer's disease (AD) is most often attributed to sustained microglial activation in response to amyloid-β (Aβ) plaque deposits and cell death. However, cytokine release and microgliosis are consistently observed in AD transgenic animal models devoid of such pathologies, bringing into question the underlying processes that may be at play during the earliest AD-related immune response. We propose that this plaque-independent inflammatory reaction originates from neurons burdened with increasing levels of soluble and oligomeric Aβ, which are known to be the most toxic amyloid species within the brain. Laser microdissected neurons extracted from preplaque amyloid precursor protein (APP) transgenic rats were found to produce a variety of potent immune factors, both at the transcript and protein levels. Neuron-derived cytokines correlated with the extent of microglial activation and mobilization, even in the absence of extracellular plaques and cell death. Importantly, we identified an inflammatory profile unique to Aβ-burdened neurons, since neighboring glial cells did not express similar molecules. Moreover, we demonstrate within disease-vulnerable regions of the human brain that a neuron-specific inflammatory response may precede insoluble Aβ plaque and tau tangle formation. Thus, we reveal the Aβ-burdened neuron as a primary proinflammatory agent, implicating the intraneuronal accumulation of Aβ as a significant immunological component in the AD pathogenesis.
Insights
Neurons burdened with amyloid-beta (Aβ) initiate inflammation in Alzheimer's disease (AD) before plaque formation. This neuron-driven immune response precedes typical AD pathologies, revealing a new therapeutic target.
Area of Science:
- Neuroscience
- Immunology
- Alzheimer's Disease Research
Background:
- Chronic inflammation, primarily microglial activation, is a hallmark of Alzheimer's disease (AD), typically linked to amyloid-beta (Aβ) plaques and neuronal death.
- However, inflammation and microgliosis occur in AD models lacking these pathologies, suggesting earlier, plaque-independent inflammatory triggers.
- Soluble and oligomeric forms of Aβ are considered the most neurotoxic species, potentially initiating immune responses within neurons.
Purpose of the Study:
- To investigate the role of neurons as a source of inflammation in early Alzheimer's disease.
- To determine if intraneuronal amyloid-beta accumulation precedes and drives neuroinflammation independently of extracellular plaques.
- To identify a unique neuronal inflammatory signature in the early stages of AD pathogenesis.
Main Methods:
- Utilized laser microdissection to isolate neurons from preplaque amyloid precursor protein (APP) transgenic rats.
- Analyzed gene and protein expression of immune factors in isolated neurons.
- Correlated neuron-derived cytokine levels with microglial activation and presence of extracellular Aβ and tau pathology in both animal models and human brain tissue.
Main Results:
- Neurons from preplaque APP transgenic rats produced significant levels of immune factors (cytokines) at both transcript and protein levels.
- Neuron-derived cytokines correlated with microglial activation and mobilization, even without observable plaques or cell death.
- Identified a distinct inflammatory profile in Aβ-burdened neurons, not mirrored in surrounding glial cells.
- Demonstrated in human brain tissue that neuron-specific inflammation can precede the formation of insoluble Aβ plaques and tau tangles.
Conclusions:
- Intraneuronal accumulation of amyloid-beta (Aβ) in neurons acts as a primary driver of inflammation in early Alzheimer's disease.
- This neuron-centric inflammatory response precedes and potentially contributes to the development of extracellular Aβ plaques and tau pathology.
- Targeting intraneuronal Aβ accumulation represents a novel therapeutic strategy for mitigating early-stage Alzheimer's disease neuroinflammation.
