Multidisciplinary analysis of protein-lipid interactions and implications in neurodegenerative disorders

Interaction of full-length Tau with negatively charged lipid membranes leads to polymorphic aggregates

The Tau protein is implicated in various diseases collectively known as tauopathies, including Alzheimer's disease and frontotemporal dementia. The precise mechanism underlying Tau pathogenicity remains elusive. Recently, the role of lipids has garnered interest due to their implications in Tau aggregation, secretion, uptake, and pathogenic dysregulation. Previous investigations have highlighted critical aspects: (i) Tau's tendency to aggregate into fibers when interacting with negatively charged lipids, (ii) its ability to form structured species upon contact with anionic membranes, and (iii) the potential disruption of the membrane upon Tau binding. In this study, we examine the disease-associated P301L mutation of the 2N4R isoform of Tau and its effects on membranes composed on phosphatidylserine (PS) lipids. Aggregation studies and liposome leakage assays demonstrate Tau's ability to bind to anionic lipid vesicles, leading to membrane disruption. Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) reveals the accumulation of Tau on the membrane surface without protein insertion, structuration, or lipid removal. Plasmon waveguide resonance (PWR) demonstrates a strong binding of Tau on PS bilayers with an apparent Kd in the micromolar range, indicating the deposition of a thick protein layer. Atomic force microscopy (AFM) real-time imaging allows the observation of partial lipid solubilization and the deposition of polymorphic aggregates in the form of thick patches and fibrillary structures resembling amyloid fibers, which could grow from a combination of extracted anionic phospholipids from the membrane and Tau protein. This study deepens our understanding of full-length Tau's multifaceted interactions with lipids, shedding light on potential mechanisms leading to the formation of pathogenic Tau assemblies.

Prediction of the binding interactions between rosmarinic acid and cysteinyl leukotriene receptor type 1 by molecular docking and immobilized receptor chromatography

Drug-protein interaction analysis is still at the center of research efforts to illustrate binding mechanisms and provide valuable information for selecting drug candidates with ideal properties in the early drug discovery stage. We present the prediction of the binding of rosmarinic acid (RA) to cysteinyl leukotriene receptor type1 (CysLTR1) by molecular docking. According to our findings, CysLTR1 is a potential anti-inflammatory target of RA. Under this assumption, we prepared the immobilized CysLTR1 column via a one-step method and characterized the immobilized CysLTR1 by fluorescent and chromatographic analyses. Furthermore, we used the immobilized CysLTR1 column to evaluate the binding interactions between RA and the immobilized receptor. Molecular docking showed that Tyr 249, Phe 174, Thr 280, Pro 177, and Thr 100 are the main sites for RA to interact with CysLTR1. The main forces that drive the findings are hydrogen bonds and hydrophobic interactions. Characterization results show that CysLTR1 is successfully immobilized with high specificity and stability. Almost no non-specific binding is observed on the immobilized CysLTR1 gels. The association constant and the binding sites are calculated to be 7.268 × 105 L mol-1 and 1.237 × 10-8 mol L-1 by injection amount-dependent method. These results, taken together, confirm the potential target of RA on the anti-inflammatory effect. We believe that it can provide valuable reference information on the in-depth exploration of drug-protein interaction mechanisms, and lead compound screening by this method.

Polymersomes for Therapeutic Protein and Peptide Delivery: Towards Better Loading Properties

Therapeutics based on proteins and peptides have profoundly transformed the landscape of treatment for diseases, from diabetes mellitus to cancers, yet the short half-life and low bioavailability of therapeutic proteins and peptides hinder their wide applications. To break through this bottleneck, biomolecules-loaded polymersomes with strong adjustability and versatility have attracted more and more attentions recently. Loading proteins or peptides into polymersomes is the first but extremely important step towards developing high-quality formulation products. However, increasing protein and peptide loading content is quite challenging due to the inherent nature of self-assembled vesicle formation mechanism and physiochemical characteristics of biomacromolecules. This review highlights the potential of polymersomes as the next-generation therapeutic proteins and peptides carrier and emphatically introduces novel approaches and recent progress to achieve satisfactory encapsulation capability of polymersomes for proteins and peptides. On the one hand, with the help of intermolecular interactions, such as electrostatic, lipid-protein, and hydrophobic interactions, the drug loading could be significantly improved. On the other hand, loading improvement could be attained through innovation of preparation methods, ranging from modified traditional film hydration techniques to the novel phase-guided assembly method.