Alzheimer’s disease, characterized by progressive cognitive decline and memory impairment, affects millions worldwide. A critical pathological feature of this neurodegenerative disorder is the formation of amyloid plaques, which disrupt neural communication and trigger inflammatory responses. The accumulation of amyloid-beta peptides is thought to be a direct consequence of proteolytic activity, particularly that of cathepsin B. By inhibiting this protease, there is potential to ameliorate or even halt the neurodegenerative process associated with Alzheimer’s disease.

Cathepsin B is primarily known for its role in the lysosomal degradation of proteins, but its involvement in amyloidogenesis is an area of growing interest. It has been shown that cathepsin B can cleave amyloid precursor protein (APP), leading to the production of amyloid-beta. This dual role as both a degradative enzyme and a contributor to amyloid plaque formation presents a tantalizing opportunity for therapeutic intervention. By selectively targeting cathepsin B, researchers aim to mitigate its pathological effects without completely disrupting its physiological functions.

Employing structural dynamics, the study elucidates the conformational states of cathepsin B and identifies potential binding sites for natural inhibitors. This method allows for a detailed understanding of the enzyme’s behavior in the presence of various ligands. Such insights are crucial for the design of more potent and specific inhibitors that could effectively disrupt the pathological cycle initiated by amyloid-beta accumulation.

Network pharmacology further complements this approach by enabling the integration of multiple biological data sources to reveal complex interactions between cathepsin B, amyloid-beta, and other cellular pathways. By mapping these interactions, researchers can better understand the broader implications of targeting cathepsin B and how it fits into the multifaceted landscape of Alzheimer’s disease. This systems biology perspective underscores the necessity of a holistic approach when developing therapies, where one intervention can influence several pathways simultaneously.

The selection of natural inhibitors based on their structural compatibility with cathepsin B marks a significant advancement in drug discovery. The advantage of natural compounds lies in their potential to exhibit lower toxicity and higher selectivity towards their targets compared to synthetic drugs. Moreover, many natural compounds have been shown to possess neuroprotective properties, which could provide an added benefit in the context of Alzheimer’s disease. This study taps into the wealth of biodiversity available in nature to identify promising candidates for further development.

The researchers employed sophisticated computational techniques to screen a library of natural compounds against cathepsin B, assessing both binding affinity and the stability of ligand-enzyme complexes. Promising candidates were then subjected to more rigorous in vitro and in vivo testing to evaluate their efficacy in reducing amyloid-beta levels and their impact on cognitive functions. Such a stepwise and thorough assessment of potential therapeutics ensures that only the most effective candidates progress to clinical trials.

The results thus far have been promising, indicating that selected natural inhibitors not only bind effectively to cathepsin B but also significantly reduce its enzymatic activity in cellular models. This reduction in cathepsin B activity correlates with lower levels of amyloid-beta, suggesting a mechanism through which these inhibitors may exert their neuroprotective effects. The potential for these compounds to provide tangible benefits in the cognitive domain of Alzheimer’s patients adds an essential dimension to this research.

An important consideration in the field of Alzheimer’s drug development is the challenge of delivering therapeutic agents across the blood-brain barrier (BBB). The study’s authors recognize this hurdle and propose formulations that enhance bioavailability and targeted delivery of natural inhibitors to the central nervous system. Innovative methods, such as liposomal encapsulation or the use of nanocarriers, could facilitate the transport of these compounds, maximizing their therapeutic potential while minimizing systemic side effects.

While the study highlights the promise of targeting cathepsin B through natural inhibitors, it also acknowledges the complex and multifactorial nature of Alzheimer’s disease. The interplay among various pathological processes—including neuroinflammation, tau phosphorylation, and oxidative stress—must be considered when designing therapeutic strategies. As such, combination therapies that simultaneously target multiple pathways may offer a more effective approach in managing this challenging condition.

Continued research into the role of cathepsin B in Alzheimer’s disease and the exploration of natural inhibitors could pave the way for new treatments that not only address amyloid-beta dysregulation but also contribute to overall brain health. Such advancements are essential, given the urgent need for effective therapies in a disease that places an immense emotional and economic burden on patients, families, and healthcare systems.

In light of these findings, the study serves as a catalyst for further exploration into the use of natural compounds as viable therapeutics in Alzheimer’s disease. As scientists and pharmacologists collaborate to deepen our understanding of the disease mechanisms involved, we may soon witness a significant shift in the landscape of Alzheimer’s treatment strategies, highlighting the potential of nature as a source of innovative solutions for one of society’s most pressing health concerns.

As ongoing research sheds more light on the intersection of natural products, protease activity, and neurodegenerative diseases, the findings of this comprehensive approach to cathepsin B inhibition will underpin future clinical endeavors. With careful attention to broader interactions and potential off-target effects, this study lays the groundwork for a new era of Alzheimer’s therapeutics, driven by holistic and integrative methodologies.

Subject of Research: Targeting cathepsin B activity in Alzheimer’s disease.

Article Title: Targeting cathepsin B activity by natural inhibitors: a structural dynamics and network pharmacology approach for amyloid-beta dysregulation in Alzheimer’s disease.

Article References:

Alam, P., Sharma, P., Kirtipal, N. et al. Targeting cathepsin B activity by natural inhibitors: a structural dynamics and network pharmacology approach for amyloid-beta dysregulation in Alzheimer’s disease.
Mol Divers (2025). https://doi.org/10.1007/s11030-025-11388-z

Image Credits: AI Generated

DOI: 10.1007/s11030-025-11388-z

Keywords: Alzheimer’s disease, cathepsin B, amyloid-beta, natural inhibitors, structural dynamics, network pharmacology, neurodegeneration, therapeutic strategies.

The trial is notable for being the first to administer empagliflozin—a drug primarily used for diabetes and cardiovascular health—to non-diabetic patients with Alzheimer’s. Empagliflozin belongs to the class of sodium-glucose cotransporter 2 (SGLT2) inhibitors, which helps regulate glucose reabsorption in the kidneys, thereby improving systemic insulin sensitivity and cardiovascular outcomes. The decision to investigate it in a neurological context stems from growing evidence that metabolic dysfunction and vascular impairment are critical drivers in the pathogenesis of Alzheimer’s, beyond the classical amyloid-beta and tau protein perspectives.

Alzheimer’s disease has long been characterized by accumulations of amyloid plaques and tau tangles in the brain, but recent emphasis on metabolic and vascular contributors provides a fresh frontier for therapeutic strategies. Traditional anti-amyloid medications, while a significant step forward, offer only modest benefits and are restricted in use due to side effects and contraindications. These drugs also fail to address upstream dysfunctions in brain metabolism and blood flow, which fuel neurodegeneration and cognitive decline. Thus, the Wake Forest study positions metabolism as a strategic target to slow or potentially halt disease progression.

Led by Suzanne Craft, Ph.D., director of the Wake Forest Alzheimer’s Disease Research Center, the study enrolled a cohort of 47 older adults averaging 70 years of age. Participants with mild cognitive impairment or early Alzheimer’s were randomized into four groups: intranasal insulin alone, empagliflozin alone, both drugs combined, or placebo. The trial’s design meticulously aimed at dissecting the differential and potentially synergistic impacts of these metabolic modulators on brain function and pathology.

Intranasal insulin was administered through a novel, precision-engineered cartridge pump device developed by Aptar Pharma, designed to deliver the peptide hormone directly into the central nervous system via the nasal-olfactory route. This delivery circumvents the systemic circulation and blood-brain barrier, enabling targeted activation of insulin receptors across synapses, vasculature, and glial support cells. Insulin signaling in the brain plays a pivotal role in maintaining synaptic plasticity, cerebral blood flow, white matter integrity, and immune regulation—all processes impaired in Alzheimer’s pathology.

Over the course of four weeks, the intranasal insulin group exhibited significant cognitive enhancements, particularly in sensitive tasks assessing memory and executive functions, areas commonly compromised in early Alzheimer’s. Neuroimaging confirmed increased white matter structural integrity and modulated regional cerebral blood flow patterns in areas critical to memory. Moreover, the treatment lowered levels of plasma glial fibrillary acidic protein (GFAP), an astrocyte dysfunction biomarker implicated in neuroinflammatory responses and blood-brain barrier disruption.

In contrast, empagliflozin showed a distinct yet complementary biochemical effect. Cerebrospinal fluid analyses revealed a marked reduction in tau protein concentrations, a hallmark of AD neurofibrillary degeneration. Additionally, decreases in neurogranin—a postsynaptic protein involved in synaptic plasticity—and vascular injury markers suggest empagliflozin acts to mitigate synaptic loss and microvascular dysfunction, key drivers in cognitive decline. The drug’s capacity to elevate high-density lipoprotein (HDL) cholesterol further confirms its broad metabolic benefits, extending beyond glycemic control into neurovascular health.

Interestingly, both medications exerted immunomodulatory effects, influencing cerebrospinal fluid and systemic inflammatory mediator levels. The data indicate activation of protective immune pathways while dampening deleterious neuroinflammation, a central component of Alzheimer’s pathophysiology. The unique impact of intranasal insulin on proteins associated with the nasal-olfactory plexus highlights its potential to leverage the brain’s glymphatic and immune clearance systems, which are increasingly recognized for their roles in waste removal and neuroimmune communication.

This bifurcated mechanism—empagliflozin’s systemic metabolic and vascular enhancement paired with intranasal insulin’s direct neurotrophic and immune-modulating actions—offers a complementary therapeutic paradigm. Empagliflozin’s ability to reduce oxidative stress and support mitochondrial energetics further bolsters cellular resilience against degenerative insults, while intranasal insulin promotes synaptic maintenance and vascular regulation critical for cognitive preservation.

The clinical trial affirmed the safety and tolerability of both agents in non-diabetic participants, with high adherence rates and minimal mild side effects uniformly across study arms. The intranasal device received excellent user acceptability scores, crucial for potential long-term treatment feasibility. Despite the relatively short duration of four weeks, these mechanistic and functional changes provide compelling evidence for extending and scaling such interventions.

Looking forward, the research team plans to pursue larger, longer-duration studies, including subjects in preclinical stages of Alzheimer’s, to validate and expand upon these encouraging findings. The prospect of combining metabolic modulators like empagliflozin and intranasal insulin with existing and emerging Alzheimer’s therapies may revolutionize the treatment landscape, offering personalized, multifaceted strategies that target the diverse pathological processes driving this disease.

Because both empagliflozin and intranasal insulin are FDA-approved for other indications with established safety profiles, their repurposing for Alzheimer’s could expedite clinical availability, an urgent need in a field where therapeutic options remain limited. This study exemplifies a promising shift towards addressing the metabolic and vascular roots of neurodegeneration rather than solely focusing on amyloid and tau pathology.

The research was generously funded by the Alzheimer’s Association’s “Part the Cloud” initiative, which supports innovative clinical trials aimed at slowing, stopping, or curing Alzheimer’s disease. This philanthropic effort, sparked by Michaela “Mikey” Hoag and others, has mobilized nearly $90 million to propel diverse investigational treatments through clinical pipelines, reflecting the complex and multifactorial nature of Alzheimer’s requiring tailored combination therapies.

In summary, the Wake Forest trial offers compelling evidence that targeting brain metabolism and vascular health using empagliflozin and intranasal insulin can modulate pathological markers, improve cognition, and normalize neurovascular and immune functions in early Alzheimer’s disease. These promising metabolic modulators could help close the significant therapeutic gaps unaddressed by existing Alzheimer’s treatments, heralding a new era of precision medicine in neurodegenerative disease management.

Subject of Research: People

Article Title: A phase 2A/B randomized trial of metabolic modulators intranasal insulin and empagliflozin for MCI and early AD

News Publication Date: October 16, 2025

Web References:

• Alzheimer’s & Dementia Journal Article
• Wake Forest University School of Medicine

Keywords: Alzheimer disease, neurodegenerative diseases, dementia, diabetes, insulin