Protective Role of a Donepezil-Huprine Hybrid against the β-Amyloid (1-42) Effect on Human Erythrocytes

Differential scanning calorimetry in drug-membrane interactions

Differential Scanning Calorimetry (DSC) is a central technique in investigating drug - membrane interactions, a critical component of pharmaceutical research. DSC measures the heat difference between a sample of interest and a reference as a function of temperature or time, contributing essential knowledge on the thermally induced phase changes in lipid membranes and how these changes are affected by incorporating pharmacological substances. The manuscript discusses the use of phospholipid bilayers, which can form structures like unilamellar and multilamellar vesicles, providing a simplified yet representative membrane model to investigate the complex dynamics of how drugs interact with and penetrate cellular barriers. The manuscript consolidates data from various studies, providing a comprehensive understanding of the mechanisms underlying drug - membrane interactions, the determinants that influence these interactions, and the crucial role of DSC in elucidating these components. It further explores the interactions of specific classes of drugs with phospholipid membranes, including non-steroidal anti-inflammatory drugs, anticancer agents, natural products with antioxidant properties, and Alzheimer's disease therapeutics. The manuscript underscores the critical importance of DSC in this field and the need for continued research to improve our understanding of these interactions, acting as a valuable resource for researchers.

Exploring Multitarget Strategies for Membrane Protection in Alzheimer's Disease

The exploration of multitarget molecules presents a promising avenue in the quest for effective therapeutic strategies against Alzheimer's disease (AD), a multifactorial neurodegenerative disorder. Traditional single-target drugs have shown limited success due to the complex interplay of pathological processes involved in AD. Multitarget-directed ligands (MTDLs), designed to interact with multiple targets simultaneously, offer a more holistic approach to address the multifaceted nature of neurodegenerative diseases. Recent studies have highlighted the potential of chalcones and huprine derivatives in mitigating amyloid-β peptide-associated toxicity and preserving membrane integrity, crucial for cellular homeostasis. The interaction of these compounds with lipid bilayers may modulate biological responses, opening a new realm of investigation in membrane-centric phenomena. This approach not only broadens the mechanistic understanding of bioactive compounds but also underscores the need for a paradigm shift in AD research, focusing on both intracellular targets and plasma membrane protection for more effective treatment strategies.

A rhein-huprine hybrid protects erythrocyte membrane integrity against Alzheimer's disease related Aβ(1-42) peptide

Alzheimer's disease remains largely unknown, and currently there is no complete cure for the disease. New synthetic approaches have been developed to create multi-target agents, such as RHE-HUP, a rhein-huprine hybrid which can modulate several biological targets that are relevant to the development of the disease. While RHE-HUP has shown in vitro and in vivo beneficial effects, the molecular mechanisms by which it exerts its protective effect on cell membranes have not been fully clarified. To better understand RHE-HUP interactions with cell membranes, we used synthetic membrane models and natural models of human membranes. For this purpose, human erythrocytes and molecular model of its membrane built-up of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE) were used. The latter correspond to classes of phospholipids present in the outer and inner monolayers of the human erythrocyte membrane, respectively. X-ray diffraction and differential scanning calorimetry (DSC) results indicated that RHE-HUP was able to interact mainly with DMPC. In addition, scanning electron microscopy (SEM) analysis showed that RHE-HUP modified the normal biconcave shape of erythrocytes inducing the formation of echinocytes. Moreover, the protective effect of RHE-HUP against the disruptive effect of Aβ(1-42) on the studied membrane models was tested. X-ray diffraction experiments showed that RHE-HUP induced a recovery in the ordering of DMPC multilayers after the disruptive effect of Aβ(1-42), confirming the protective role of the hybrid.

Advances in Amyloid-β Clearance in the Brain and Periphery: Implications for Neurodegenerative Diseases

This review examines the role of impaired amyloid-β clearance in the accumulation of amyloid-β in the brain and the periphery, which is closely associated with Alzheimer's disease (AD) and cerebral amyloid angiopathy (CAA). The molecular mechanism underlying amyloid-β accumulation is largely unknown, but recent evidence suggests that impaired amyloid-β clearance plays a critical role in its accumulation. The review provides an overview of recent research and proposes strategies for efficient amyloid-β clearance in both the brain and periphery. The clearance of amyloid-β can occur through enzymatic or non-enzymatic pathways in the brain, including neuronal and glial cells, blood-brain barrier, interstitial fluid bulk flow, perivascular drainage, and cerebrospinal fluid absorption-mediated pathways. In the periphery, various mechanisms, including peripheral organs, immunomodulation/immune cells, enzymes, amyloid-β-binding proteins, and amyloid-β-binding cells, are involved in amyloid-β clearance. Although recent findings have shed light on amyloid-β clearance in both regions, opportunities remain in areas where limited data is available. Therefore, future strategies that enhance amyloid-β clearance in the brain and/or periphery, either through central or peripheral clearance approaches or in combination, are highly encouraged. These strategies will provide new insight into the disease pathogenesis at the molecular level and explore new targets for inhibiting amyloid-β deposition, which is central to the pathogenesis of sporadic AD (amyloid-β in parenchyma) and CAA (amyloid-β in blood vessels).

Amyloid β and Alzheimer's Disease: Molecular Updates from Physiology to Pathology

Alzheimer's disease (AD) represents one of the most challenging disorders, and despite having been widely studied since its first identification, resolutive treatments are still far out of reach [...].

Nano C60 Promotes Synaptic Distribution of Phosphorylated CaMKIIα and Improves Cognitive Function in APP/PS1 Transgenic Mice

The wide disparity in outcomes of Alzheimer's disease (AD) treatment from preclinical to clinical studies suggests an urgent need for more effective therapeutic targets and approaches to treat AD. CaMKII is a potential target for AD therapy; however, conflicting reports on the relationship between CaMKII and AD suggest a lack of deeper understanding of the interaction between CaMKII and AD. In addition to the lack of effective therapeutic targets, pharmacokinetic limitations of neuroprotective drugs, such as low lipophilicity to cross blood brain barrier, need to be urgently addressed in the practice of AD therapy. In this study, we prepared a carbon-based nanoparticle, Nano C60, and demonstrated that Nano C60 treatment promoted the translocation of phosphorylated CaMKIIα from the cytoplasm to the synapse in Aβ42 oligomers-treated cells and APP/PS1 mice. As a result, Nano C60 administration significantly improved spatial learning and memory in APP/PS1 mice. Our study suggests that synaptic-activated CaMKII may be more important than total CaMKII in AD treatment and provides a new strategy for AD therapy.