Alzheimer’s disease (AD) is a progressive neurodegenerative disorder marked by cognitive decline and abnormal behavior (1–3). By 2024, an estimated 6.9 million Americans aged 65 and older will have Alzheimer’s dementia, potentially rising to 13.8 million by 2060 without medical advances (4). The aging population contributes to its increasing prevalence, posing a significant public health challenge (5, 6). AD pathogenesis involves multiple pathological processes, including amyloid-beta (Aβ) protein deposition, neurofibrillary tangles from Tau protein phosphorylation, chronic neuroinflammation, and disrupted insulin signaling in the brain, alongside genetic factors and environmental exposures (2, 3, 7–9). Recent research has increasingly indicated that the artificial sweetener aspartame, along with its metabolites, possesses the capability to traverse the blood–brain barrier, thereby inducing oxidative stress responses and enhancing neuroinflammation. This process may contribute to and expedite neuronal degeneration (10–12).

Aspartame, a prevalent artificial sweetener, is extensively utilized in a variety of low-calorie foods and beverages. Although its safety has been endorsed by certain regulatory bodies, a growing body of neurotoxicity research suggests that its metabolites, including phenylalanine, aspartic acid, and methanol, can permeate the blood–brain barrier, accumulate within the central nervous system, and potentially initiate pathological processes associated with the onset of AD (10, 13–15). Empirical evidence indicates that aspartame may exacerbate the aberrant deposition of Aβ protein and the hyperphosphorylation of Tau protein by promoting oxidative stress in the brain, compromising the integrity of neuronal cell membranes, and activating neuroinflammatory pathways (10, 14, 16). Despite the current insufficiency of epidemiological evidence and the ongoing controversy surrounding mechanistic research, numerous experiments indicate that prolonged and excessive consumption of aspartame may lead to neuronal dysfunction and cognitive impairment (13, 17, 18). Considering the widespread use of aspartame in food products and its potential biological effects on the central nervous system, it is of substantial neurotoxicological and public health importance to conduct comprehensive research into the molecular mechanisms and population risks associated with AD.

To investigate the potential link between aspartame and AD, this study employed a comprehensive computational approach that integrates network toxicology, and molecular docking to systematically examine the neurotoxic mechanisms involved. A multi-dimensional interaction network comprising “compound - target - pathway” was developed using network toxicology to identify AD-related signaling pathways and biological processes that may be influenced by aspartame. Molecular docking was utilized to simulate the binding modes and affinities of aspartame with key targets, thereby assessing its potential for interference. This integrated methodology facilitates a systematic elucidation of the multi-target mechanisms through which aspartame may contribute to the progression of AD, providing a theoretical foundation for environmental health risk assessments. Additionally, it offers a computational toxicology framework for evaluating the neurotoxicity of food additives.

Alzheimer’s disease, a progressive neurodegenerative disorder, is characterized by distinct pathological features, including the abnormal deposition of Aβ protein in the brain parenchyma, and the aggregation of hyperphosphorylated Tau protein within neurons (9, 21–23). Although the precise etiology of AD remains incompletely understood, it is widely accepted within the academic community that its pathogenesis arises from a complex interplay between genetic predisposition and prolonged environmental exposure (24–26). Beyond the classical Aβ cascade hypothesis and the Tau protein hypothesis, neuroinflammation has been identified as a critical factor driving the pathological progression of AD (27–30). Pro-inflammatory cytokines in the peripheral circulation can penetrate the central nervous system through alterations in blood–brain barrier permeability or by activating resident microglia in the brain, thereby initiating and sustaining a chronic inflammatory cascade within the cerebral environment (31–33). This persistent state of neuroinflammation not only directly contributes to neuronal damage but also exacerbates the aggregation of Aβ and the pathological alterations of Tau protein, thereby creating a vicious cycle that ultimately accelerates cognitive decline (34–36). Aspartame, a widely utilized artificial sweetener, is metabolized in the body into components such as phenylalanine, aspartic acid, and methanol. Existing research indicates that the neurotoxic effects induced by aspartame may involve multiple mechanisms, including neuroinflammation, oxidative stress, mitochondrial dysfunction, and apoptosis (10, 14, 16, 18, 37). In this context, a systematic investigation into the relationship between aspartame consumption and the onset and progression of AD, as well as its underlying mechanisms, is of substantial scientific and public health importance.

Utilizing network toxicology and molecular docking, this study peculated the potential molecular mechanisms through which aspartame may contribute to the pathogenesis of AD. By integrating and analyzing data from multiple databases, the study obtained 298 targets associated with aspartame and 2,042 targets related to AD. From this dataset, seven core targets—BCL2, PPARG, TNF, IL1β, MAPK3, ESR1, and CASP3— were speculated as potential mediators of the interaction between aspartame and AD. The molecular docking results indicated that aspartame had a good binding affinity with some core targets. It is speculated that aspartame may interfere with the signaling pathways related to AD through its interaction with these key proteins. Further KEGG enrichment analysis revealed significant enrichment in the TNF signaling pathway, MAPK signaling pathway, and PI3K-Akt signaling pathway. These pathways collectively regulate critical pathological processes in AD, such as neuroinflammatory response, apoptosis, and oxidative stress, thereby speculating on the potential mechanisms by which aspartame exposure may be involved in the occurrence and development of the disease.

This study hypothesizes that the primary targets identified are intricately linked to the key pathological mechanisms of AD. A central objective of AD research is to mitigate the accumulation of abnormal tau protein. Through the application of multispectral analysis on the brain tissues of individuals who succumbed to AD, it was observed that hyperphosphorylated tau protein was associated with numerous proteins from the BCL2 family. The findings of this research demonstrate that inhibiting BCL2 can substantially alleviate the tau protein burden (38). Additionally, the study reveals that aspartame can induce the upregulation of CASP3 expression and the downregulation of BCL2 expression (39). This theoretically represents one of the potential mechanisms that may increase the risk of AD. AD represents the most prevalent form of dementia, with neuroinflammation serving as a critical marker of its pathogenesis (35). TNF and its type 1 receptor are implicated not only in the neuroinflammatory processes associated with AD but also in amyloid protein formation through the regulation of β-secretase (40, 41). This dual role positions TNF as a promising candidate for therapeutic intervention in AD. Furthermore, TNF contributes to AD pathogenesis by mediating neuronal cell death. The inhibition of TNF-α holds potential as a therapeutic strategy to prevent AD and enhance cognitive function in populations at elevated risk for dementia (40, 41). TNF can also upregulate the expression of IL-1, thereby increasing the production of precursor substances essential for the formation of amyloid plaques, neurofibrillary tangles, and Lewy bodies (42). Additionally, TNF acts as a primary upstream mediator of inflammation within the choroid plexus tissue of AD patients (41). Previous research has demonstrated that aspartame can induce the formation of the pro-inflammatory factor TNF-α in serum (41, 43). Elevated levels of IL1β serve as pivotal mediators of inflammation and are expressed in the brain, particularly within the hippocampus, where they play an essential role in the regulation of memory and mood. Within the brain, IL1β is implicated in various processes, including neuronal proliferation, differentiation, apoptosis, and long-term potentiation (44). IL1β is also involved in the pathogenesis of AD and has an impact on cognitive function (44). Empirical studies have demonstrated that aspartame consumption can lead to an increase in the pro-inflammatory cytokine IL1β in the serum, thereby inducing systemic inflammation (30, 43). MAPK3 is involved in the regulation of cytokine, neurotransmitter, and hormone signal transduction, influencing gene expression, cell proliferation, and apoptosis. In the context of AD, the activation of the MAPK3 signaling pathway is closely associated with excessive microglial activation and the release of pro-inflammatory factors, which are critical pathological features of the disease (45). Inhibition of the MAPK3 pathway has been shown to reduce neuroinflammation and slow the progression of AD (46). Relevant research has demonstrated that MEP may activate the MAPK3 pathway, leading to an increased production and release of inflammatory mediators, thereby exacerbating neuronal damage and accelerating the pathological progression of AD. Aspartame has been shown to elevate levels of inflammatory mediators, potentially causing neuronal damage and further accelerating the pathological process of AD (10, 39). Apoptotic damage and subsequent cell death are critical factors in the neurodegeneration associated with AD. CASP3 plays a significant role in nervous system development and neuronal death under specific pathological conditions (47). Furthermore, both in vitro and in vivo studies have reported elevated expression and activation of CASP3 in AD models. Studies have confirmed that aspartame can induce the upregulation of CASP3 expression and promote cell apoptosis (47, 48). Additionally, Mendelian studies have identified that increased expression of the PPARG gene in the blood serves as an important protective factor against early-onset AD (49). ESR1 gene is ubiquitously expressed throughout the brain. Given the potential neuroprotective effects of estrogen, the ESR1 gene emerges as a candidate for modulating the development of AD (50–52). Notably, molecular docking studies have demonstrated that aspartame exhibits substantial binding affinity to these targets, indicating a possible direct interference with their physiological functions. Numerous experimental investigations have revealed that exposure to aspartame in animal models induces histopathological alterations across various brain regions, including increased oxidative stress markers and neuronal loss (10, 17). Furthermore, these studies have identified impairments in memory and learning, alongside behavioral and emotional dysfunctions in the animal models (13, 15, 17, 18). Abhilash M. et al. have highlighted that prolonged aspartame consumption can disrupt the antioxidant/pro-oxidant balance within the brain (14). The accumulation of neurotoxic metabolites in the central nervous system following extended dietary exposure raises concerns regarding potential damage to the cerebral cortex associated with aspartame. Aspartame has been shown to up-regulate CASP3 expression while down-regulating BCL2 expression, indicating the activation of apoptotic pathways and consequently exacerbating detrimental effects on the central nervous system (39). Furthermore, aspartame exposure is associated with elevated levels of pro-inflammatory cytokines, specifically TNF-α and IL1β, in the serum, which may precipitate systemic inflammation (43). Empirical evidence from animal studies has substantiated the impact of chronic aspartame exposure on oxidative stress within the cerebral tissue of albino rats (12). While molecular docking offers structural insights into target interactions, it is crucial to acknowledge the inherent limitations of computational simulations (53). Factors including the static nature of protein conformations, solvation effects, and in vivo metabolic kinetics can significantly influence the actual binding scenarios. Consequently, these findings primarily function as mechanistic hypotheses and require further validation of their biological relevance through in vitro experiments, such as those involving microglial and neuronal cell lines, as well as in vivo studies using animal models like APP/PS1 transgenic mice.

KEGG pathway enrichment analysis suggests that aspartame may play a role in the pathological processes of AD by modulating multiple signaling pathways. The TNF signaling pathway is implicated not only in the neuroinflammation associated with AD but also in amyloid protein formation through the regulation of β-secretase (40). Previous studies have demonstrated that aspartame can induce the production of the pro-inflammatory factor TNF-α in serum, thereby activating the TNF signaling pathway (43, 54). The MAPK signaling pathway has significant effects on memory, neuroinflammatory programming, and synaptic plasticity (45, 55). Consequently, clinical trials involving various MAPK inhibitors, which exhibit favorable safety profiles and minimal side effects, have yielded positive outcomes in AD patients, suggesting that targeting MAPK may effectively mitigate AD pathogenesis (45, 46, 56). Additionally, the PI3K/AKT signaling pathway has been identified as a pathway activated by multiple stimuli, including insulin, growth factors, cytokines, and cellular stress (48, 57–59). This pathway contributes to neuronal survival, regulates the phosphorylation of Tau protein, and facilitates the clearance of Aβ (60). The TNF signaling pathway and the MAPK signaling pathway collectively constitute the central network of the inflammatory response. Notably, TNF-α can further amplify the inflammatory signal by activating the MAPK cascade. It is important to highlight that the MAPK signaling pathway also plays a role in regulating the phosphorylation level of Tau protein (45). Dysregulation of these pathways results in the accumulation of Aβ, excessive phosphorylation of tau, and mitochondrial dysfunction, thereby forming a negative feedback loop that accelerates disease progression. Studies have indicated that aspartame may indirectly influence the formation of neurofibrillary tangles via this pathway. Research has demonstrated that aspartame can induce oxidative stress and activate these signaling pathways, modulating them through various mechanisms, including inflammation (TNFα, IL6, IL1β), enhanced oxidative stress (MDA), and the apoptotic pathway CASP3, ultimately leading to neuronal damage and promoting the onset and progression of AD (10).

As a computational exploratory study, the core value of this research lies in generating verifiable hypotheses. Although we have made every effort to correlate the prediction results with previous experimental evidence, the network pharmacology method itself has inherent limitations, such as the inability to simulate the complex pharmacokinetics, blood–brain barrier permeability and cell type specificity in vivo. The conclusion needs to be ultimately confirmed in subsequent experiments (53). Subsequent research should be further expanded in the following areas: Firstly, the regulatory effects of aspartame on the expression and function of core targets such as TNF and CASP3 should be verified using cell models, with particular emphasis on its impact within the microglia–neuron co-culture system. Secondly, transgenic animal models of AD should be employed to assess the in vivo effects of prolonged aspartame consumption on key pathological indicators, including Aβ deposition, Tau protein phosphorylation, and neuroinflammation. Finally, rigorous epidemiological studies should be designed to analyze the dose–response relationship between varying levels of aspartame intake and the risk of cognitive decline or AD onset. Establishing such a multi-tiered experimental validation framework is essential for a comprehensive evaluation of aspartame’s role as an environmental risk factor in the pathogenesis and progression of AD.

This study employed a combined approach of network toxicology and molecular docking to speculate on the potential role of aspartame in the pathogenesis of AD. The research results speculate that aspartame may be involved in this pathological process through a series of biological mechanisms, including interfering with neuroinflammatory responses, apoptosis and oxidative stress. Current research merely provides speculative evidence for the potential neurotoxicity of aspartame, and further empirical verification of its biological functions is still needed. The subsequent research should integrate in vitro neuronal models, transgenic animal experiments and population-based epidemiological studies to speculate on the possible mechanisms and clinical significance of aspartame in the occurrence and development of AD from multiple perspectives.