Alzheimer’s disease (AD) is one of the most prevalent neurodegenerative diseases on a global scale. Historically, this pathology has been linked to cholinergic transmission, and despite the scarcity of effective therapies, numerous alternative processes and targets have been proposed as potential avenues for comprehending this complex illness. Nevertheless, the fundamental pathophysiological mechanisms underpinning AD remain largely enigmatic, with a growing body of evidence advocating for the significance of muscarinic receptors in modulating the brain’s capacity to adapt and generate new memories. This review summarizes the current state of the art in the field of muscarinic receptors’ involvement in AD. A specific key factor was the relationship between comorbidity and the emergence of new mechanisms.

Alzheimer’s disease (AD) is a progressive neurodegenerative disease characterized by cognitive decline, memory loss, and behavioural changes. While genetic predispositions and pathological processes have been the traditional focus, this review highlights the fundamental role of environmental factors, particularly nutrition, within the exposome framework in modulating the risk and progression of AD. The exposome, which includes the totality of environmental exposures in an individual’s lifetime, provides a comprehensive approach to understanding the complex aetiology of AD. In this review, we explore the impact of dietary factors and cyclic nucleotide pathways (cAMP/cGMP) on AD, emphasizing the potential of dietary interventions as therapeutic strategies. We investigate key aspects of how nutrition affects the accumulation of β-amyloid, the aggregation of tau proteins, and neuroinflammation. We also examine the impact of specific nutrients on cognitive performance and the risk of AD. Additionally, we discuss the potential of nutraceuticals with anti-phosphodiesterase activity and the role of various animal models of AD (such as 5xFAD, 3xTg-AD, Tg2576, and APP/PS1 mice) in demonstrating the effects of dietary interventions on disease onset and progression.

Alzheimer’s disease (AD) involves a constellation of molecular processes that extend well beyond amyloid-β (Aβ) accumulation. Recent anti-amyloid antibodies provide limited clinical benefits, highlighting the need for additional strategies due to their modest efficacy and safety concerns. Increasing proteomic evidence reveals that proteins such as midkine (MDK), pleiotrophin (PTN) and clusterin (CLU) accumulate within amyloid plaques and may shape disease progression, although their precise contributions—protective, pathogenic, or both—remain unknown. In this Perspective, we examine how emerging targeted protein degradation (TPD) technologies, including Proteolysis-Targeting Chimeras (PROTACs), Lysosome-Targeting Chimeras (LYTACs) and molecular glues (MGs), could provide a means to selectively eliminate these co-aggregating proteins. We also discuss advances in degrader design, artificial intelligence (AI)-assisted screening, and strategies aimed at enhancing Central Nervous System (CNS) delivery. We finally outline how integrating TPD modalities with antibody-based and multi-target therapeutic approaches may promote more effective, systems-level interventions for AD.

Ongoing global research actions seek to comprehensively understand the adverse impact of stress and anxiety on the physical and mental health of both human beings and animals. Niaprazine (NIA) is a chemical compound that belongs to the class of piperazine derivatives. This compound has recently gained renewed attention due to its potential therapeutic properties for treating certain conditions such as anxiety. Despite its potential benefits, the behavioral effects of NIA have not been thoroughly investigated. This study aimed to examine NIA’s potential as an anti-anxiety and anti-stress agent. After administering either vehicle or NIA in their drinking water to mice for 14 days, we conducted behavioral analyses using the Marble Burying Test and the Elevated Plus Maze test. NIA-treated mice spend more time in the open arms and bury fewer marbles. Moreover, a stability study confirmed the linear relationship between NIA concentration and its response across concentrations encompassing the NIA mother solution and the NIA solutions administered to mice. Also, a preliminary synaptic toxicity analysis showed no direct damage to cortical nerve endings. Here, we show that NIA can modulate anxiety-related behaviors without significantly impacting exploratory activity or adverse effects. Our work describes new findings that contribute to the research on safer and more tolerable anxiety management options.

Ellagic acid (EA) is a natural compound exerting beneficial effects in mammals, including central neuroprotection. Among the central targets, the noradrenergic pathway has been proposed as a suitable candidate and, in this view, we recently proposed the presynaptic α₂ autoreceptors as possible sites of action of this natural polyphenol. Although attractive, our hypothesis is questioned by the unfavourable pharmacokinetic profile of EA, which limits its access to the central nervous system, making impossible its interaction with these receptors. To substantiating the correlation linking EA treatment and the central noradrenergic pathway, we have now extended the study to Urolithins. These are the principal EA metabolites, which are brought in for EA central effects because of their high systemic bioavailability. To address the point, we employed a multidisciplinary approach, which included computational, "in vitro" and "in vivo" studies. The results from "computational" and "in vitro" experiments revealed that Urolithin A (UroA), but not Urolithin B (UroB) or C (UroC), binds to and activates α2 receptor subtypes. Furthermore, the "in vivo" prolonged administration of formulated microdispersion of EA (EAm) in mice led to a marked desensitization of cortical and hippocampal α₂ autoreceptors, also reducing their density. Notably, central effects were associated to a significant changes in gut microbiome composition, towards a metabotype that would preferentially produce UroA. Based on these observations, we propose UroA as one of the systemic "effectors" of the EAm-induced central noradrenergic adaptation, confirming the role of noradrenaline in mediating the EA-mediated health effects.