Biophysical chemistry最新文献_第6页

Deterministic error propagation in ITC: Revealing multi-fold errors in Kd values under standard conditions ITC中的确定性误差传播：揭示标准条件下Kd值的多重误差

IF 3.3 3区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Biophysical chemistry

Pub Date : 2025-05-08 DOI: 10.1016/j.bpc.2025.107455

Tong Ye Wang , Sergey N. Krylov

Accurate determination of the equilibrium dissociation constant (K_d) is essential in fields such as drug discovery and molecular diagnostics, where a rigorous understanding of molecular interactions drives critical decisions. Among established techniques, isothermal titration calorimetry (ITC) is highly valued for its ability to directly capture binding thermodynamics without the need for labeling or immobilization. However, while ITC is often praised for its precision, potential inaccuracies due to the systematic errors in experimental variables (analyte concentrations and measured heat) are frequently overlooked. One key reason for this oversight is the lack of a deterministic framework that explicitly demonstrates how ITC-derived K_d values can be affected by these errors. To address this gap, we derived a closed-form mathematical model for error propagation in ITC-based K_d determination, quantifying the impact of inaccuracies in analyte concentrations and measured heat on the resulting K_d. This framework provides a robust foundation for understanding and predicting the influence of these systematic errors on K_d accuracy. Using this solution, we demonstrate that even within the conventionally recommended c-value range of 10–100, expected systematic errors in concentrations and heat can potentially lead to significant multi-fold deviations in K_d. These findings underscore the need for quantitative accuracy assessments in ITC experiments and highlight the importance of developing practical tools to support such evaluations.

准确测定平衡解离常数（Kd）在药物发现和分子诊断等领域至关重要，在这些领域，对分子相互作用的严格理解驱动着关键决策。在已建立的技术中，等温滴定量热法（ITC）因其直接捕获结合热力学而无需标记或固定的能力而受到高度重视。然而，虽然ITC经常因其精度而受到称赞，但由于实验变量（分析物浓度和测量热量）的系统误差而导致的潜在不准确性经常被忽视。造成这种疏忽的一个关键原因是缺乏明确说明itc衍生的Kd值如何受到这些错误影响的确定性框架。为了解决这一差距，我们推导了一个基于tc的Kd测定误差传播的封闭数学模型，量化了分析物浓度和测量热量的不准确性对结果Kd的影响。该框架为理解和预测这些系统误差对Kd精度的影响提供了坚实的基础。使用该溶液，我们证明，即使在常规推荐的10-100 c值范围内，浓度和热量的预期系统误差也可能导致Kd的显着多倍偏差。这些发现强调了在ITC实验中进行定量准确性评估的必要性，并强调了开发实用工具以支持这种评估的重要性。

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引用次数: 0

Effects of perturbation of the hydrophobic coiled-coil core on the thermal transition process of α-helical self-assembling peptides with α-β conformational transition capability 疏水线圈芯扰动对具有α-β构象转变能力的α-螺旋自组装肽热转变过程的影响

IF 3.3 3区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Biophysical chemistry

Pub Date : 2025-05-07 DOI: 10.1016/j.bpc.2025.107456

Minami Kurokawa , Shota Nakagawa , Atsuo Tamura

We designed a 29-residue peptide (CCP1) with helical nanofiber-forming ability, in which the interface of the coiled-coil motif consists only of hydrophobic residues, and peptides with histidine residues substituted in the hydrophobic core (CCP2 and CCP3), and analyzed the effects of perturbations caused by the substitutions on the intermolecular association and conformational transitions. Based on the results of atomic force microscopy and circular dichroism measurements, it was found that CCP1 and CCP2 form α-helical fibers under pH 4, while CCP3 adopts the α-helix structure but lacks the association ability. Furthermore, the heating processes of CCP1 and CCP2 were followed by using spectroscopic, thermal, and morphological techniques, and it was observed that CCP1 undergoes an irreversible structural transition from α-helical to β-sheet fibers with a high degree of cooperativity, while a more gradual or non-cooperative structural transition was observed in CCP2. These results indicate that the introduction of histidine residues in the hydrophobic core significantly affects the intermolecular interactions and the rate of structural transition, providing a new design principle for the development of functional nanomaterials with biocompatibility.

我们设计了一种具有螺旋纳米纤维形成能力的29位残基肽（CCP1），其中卷曲线圈基序的界面仅由疏水残基和在疏水核心中取代组氨酸残基的肽（CCP2和CCP3）组成，并分析了取代引起的扰动对分子间结合和构象转变的影响。原子力显微镜和圆二色性测量结果表明，在pH值为4的条件下，CCP1和CCP2形成α-螺旋状纤维，而CCP3虽呈α-螺旋状结构，但缺乏缔合能力。此外，利用光谱、热学和形态学技术跟踪了CCP1和CCP2的加热过程，发现CCP1经历了从α-螺旋纤维到β-片纤维的不可逆结构转变，具有高度的协同性，而CCP2的结构转变更为缓慢或非合作。这些结果表明，在疏水核中引入组氨酸残基可显著影响分子间相互作用和结构转变速率，为开发具有生物相容性的功能纳米材料提供了新的设计原则。

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引用次数: 0

Two-step upconversion-driven PDT/CDT cooperative phototherapeutic platform based on surface magnetic field modulation 基于表面磁场调制的两步上变频驱动PDT/CDT协同光疗平台

IF 3.3 3区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Biophysical chemistry

Pub Date : 2025-05-05 DOI: 10.1016/j.bpc.2025.107454

Changqiu Ma , Anqi Han , Daheng Jiang , Qiuyan Wang , Linghui Zeng , Lixin Zhu , Mingya Yang , Xiaoliang Xu

Photodynamic therapy utilizes photosensitizer to generate reactive oxygen species (ROS) under irradiation of light for anticancer. However, due to the strong absorption of visible light by tissues and organs, photodynamic therapy meets challenges in deep tissues. Herein, we propose an upconversion-driven photodynamic therapy combined with chemodynamic therapy based on UCNP@SiO₂@Fe₃O₄@MC540. Upon the excitation of 980 nm laser, the visible emission of upconversion nanoparticles activates MC540 to produce ROS, which is enhanced by Fe₃O₄ through magnetic field modulation. Subsequently, Fe₃O₄ degrades under acidic conditions to produce ·OH via Fenton-reaction for chemodynamic therapy. The in vitro and in vivo experiments indicate that the two-step cooperative strategy exhibits significant anticancer efficacy. Besides, Finite Difference Time Domain (FDTD) simulation reveals that the enhancement stems from surface electric field and light absorption. It offers a deeper understanding of phototherapeutic process.

光动力疗法利用光敏剂在光照射下产生活性氧（ROS）来抗癌。然而，由于组织和器官对可见光的强烈吸收，光动力疗法在深层组织中遇到了挑战。在此，我们提出了一种基于UCNP@SiO2@Fe3O4@MC540的上转换驱动的光动力疗法结合化学动力疗法。在980 nm激光激发下，上转换纳米粒子的可见光发射激活MC540产生ROS， Fe3O4通过磁场调制增强了ROS的产生。随后，Fe3O4在酸性条件下通过fenton反应降解生成·OH进行化学动力学治疗。体外和体内实验表明，两步协同策略具有显著的抗癌效果。时域有限差分（FDTD）仿真结果表明，表面电场和光吸收是增强的主要原因。它提供了光疗过程的更深层次的理解。

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引用次数: 0

Characterization, antibacterial property, biocompatibility, and optimization of novel composite nanofibers incorporating curcumin-loaded flexible nano-liposomes 含姜黄素柔性纳米脂质体的新型复合纳米纤维的表征、抗菌性能、生物相容性和优化

IF 3.3 3区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Biophysical chemistry

Pub Date : 2025-04-29 DOI: 10.1016/j.bpc.2025.107453

Hua-Wei Chen , Chun-Hung Cheng , Yu-Hsiang Yu , Yi-Lin Chen , Chyow-San Chiou , Wei-Ting Chen

Novel composite nanofibers incorporating curcumin-loaded flexible nano-liposomes (CLFN-liposomes) were developed for applications in tissue engineering, dressings, and drug delivery and release systems in this research. The preparation of CLFN-liposomes for curcumin encapsulation through the ethanol injection method was explored through a factorial experimental design. The optimal conditions for CLFN-liposomes/polycaprolactone composite nanofiber (CLFN-liposomes/PCL) were explored using the Taguchi method, emphasizing the addition of PCL, operational voltage, and flow rate. Uniformly distributed CLFN-liposomes with a smaller mean particle size of 53.9 ± 7.4 nm and higher encapsulation efficiency of 47.3 ± 3.4 % were synthesized for effective penetration. The smallest nanofiber diameter (186.3 ± 62.3 nm) with a smooth and uniform distribution was obtained after obtaining the optimum combinations of 17 wt% PCL, 4 wt% CLFN-liposomes/PCL, 25 kV, and 0.25 mL/h flow rate. The release of curcumin from CLFN-liposomes/PCL nanofibers followed the Higuchi model kinetics, with extended release for up to 48 h due to the dual-stage release from the nano-liposomes to the nanofibers. CLFN-liposomes/PCL dressings exhibited improved wettability (70.7° ± 4.3), water uptake (730 ± 44.2 %), biocompatibility (96 %), antimicrobial activity (41.8 ± 0.8 mm and 38.0 ± 1.1 mm inhibition zone of Staphylococcus aureus and Escherichia coli), and sustained release of curcumin, surpassing existing dressings in various aspects. This, novel composite nanofibers incorporating curcumin-loaded flexible nano-liposomes were developed, with promising wound dressing and broad application prospects. This study provides a novel idea for the release and delivery of active components through liposomes.

本研究开发了含有姜黄素负载柔性纳米脂质体（clfn -脂质体）的新型复合纳米纤维，用于组织工程、敷料和药物输送和释放系统。通过析因实验设计，探讨乙醇注射法制备姜黄素包封用clfn脂质体的工艺。采用田口法考察了制备clfn -脂质体/聚己内酯复合纳米纤维（clfn -脂质体/PCL）的最佳工艺条件，重点考察了PCL的添加、操作电压和流速。合成的clfn脂质体分布均匀，平均粒径为53.9±7.4 nm，包封效率为47.3%±3.4%，具有良好的渗透效果。在17 wt% PCL、4 wt% clfn -脂质体/PCL、25 kV、0.25 mL/h流速的最佳组合下，获得的纳米纤维直径最小（186.3±62.3 nm），分布光滑均匀。clfin -脂质体/PCL纳米纤维中姜黄素的释放符合Higuchi模型动力学，由于纳米脂质体向纳米纤维的双阶段释放，姜黄素的释放延长至48 h。clfn -脂质体/PCL敷料在润湿性（70.7°±4.3）、吸水性（730±44.2%）、生物相容性（96%）、抗菌活性（对金黄色葡萄球菌和大肠杆菌的抑制区分别为41.8±0.8 mm和38.0±1.1 mm）、姜黄素缓释等方面均优于现有敷料。因此，研制了一种新型的姜黄素柔性纳米脂质体复合纳米纤维，具有良好的伤口敷料和广阔的应用前景。本研究为有效成分通过脂质体的释放和传递提供了新的思路。

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引用次数: 0

Radiation-induced alterations in the dielectric features of irradiated tissues 辐照组织介电特性的辐射诱导改变

IF 3.3 3区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Biophysical chemistry

Pub Date : 2025-04-29 DOI: 10.1016/j.bpc.2025.107452

Abdelrazek B. Abdelrazzak , Fawzy G. El Desouky

In this study, we investigated the dielectric characteristics of the brain, lung heart, liver, spleen and kidney that were either directly irradiated or were abscopal to the irradiated region, in an attempt to utilize the physical tool of dielectric spectroscopy to identify the biological effects of ionizing radiation. The dielectric analyses were performed for 1–2 mm thick freeze-dried samples, of the different organs, sandwiched between two brass electrodes at room temperature in the frequency range 0.1–10⁷ Hz. The results show notable modifications in the dielectric properties of the liver of the whole body irradiated group (WB) and the kidney of lower-limb (LL) and cranially (CR) irradiated groups. The data show increase in the imaginary electric modulus

M^{''}

and decrease in the permittivity and AC conductivity in the heart and brain of all of the irradiated groups. The data show a general trend of increase in the conductivity of the liver of WB and the kidney of CR and LL groups. The Cole-Cole plot (

M^{''}

vs.

M^{'}

), as a good depiction of the dielectric behavior of the tissues, show differential response of the different organs. The expansion of loss tangent peaks indicates relaxation dispersion with a steady relaxation time distribution for the liver, kidney and lung. The extended relaxation periods and frequency shifts to lower values results indicate variation in the rigidity of biological macromolecules in the liver, lung and kidney only. The experimental data suggest induction of abscopal effect occur in the liver, kidney, lung than heart, brain and spleen.

在本研究中，我们研究了脑、肺、心、肝、脾和肾直接或离辐照区域的介电特性，试图利用介电光谱的物理工具来识别电离辐射的生物效应。在0.1-107 Hz的频率范围内，对不同器官的1-2 mm厚的冻干样品在室温下夹在两个黄铜电极之间进行介电分析。结果表明，全身照射组（WB）肝脏、下肢照射组（LL）和颅脑照射组（CR）肾脏的介电特性有明显改变。数据显示，所有辐照组心脏和大脑的虚电模量M”增加，介电常数和交流电导率下降。数据显示，WB组的肝脏和CR、LL组的肾脏电导率均有增加的趋势。Cole-Cole图（M′vs. M′）很好地描述了组织的介电行为，显示了不同器官的差异响应。损失切线峰的扩大表明松弛色散，肝、肾和肺的松弛时间分布稳定。松弛期的延长和频率向低值移动的结果表明，生物大分子的刚性只在肝、肺和肾中发生变化。实验数据表明，肝、肾、肺比心、脑和脾更能诱导体外效应。

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引用次数: 0

Interaction process behind the strong stabilization of G-quadruplexes by alkaloid fagaronine 生物碱法加隆碱强稳定 G-四链体的相互作用过程

IF 3.3 3区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Biophysical chemistry

Pub Date : 2025-04-15 DOI: 10.1016/j.bpc.2025.107443

Pavel Hannig , Raimundo Gargallo , Stefania Mazzini , Gigliola Borgonovo , Marco Zuccolo , Eva Táborská , Petr Táborský

Benzo[c]phenanthridine alkaloids are known for their stabilizing effects on non-canonical DNA structures, particularly G-quadruplexes (G4s). In this study, the interaction of fagaronine, a rare benzo[c]phenanthridine alkaloid, with several DNA structures (including B-DNA, parallel, antiparallel and hybrid G4s) is studied using molecular fluorescence and circular dichroism (CD) spectroscopy. It has been found that fagaronine significantly enhances the stability of all tested G4 conformations. Furthermore, a study by NMR spectroscopy provided valuable information on the mechanism of interaction of the ligand with the parallel G4 structure adopted by Pu22T14T23, a sequence mutated with respect to that found within the promoter region of the c-myc gene. Remarkably, when compared with data reported in the literature, fagaronine appears to exhibit one of the strongest G4 thermal stabilization effects ever recorded for a small ligand.

苯并[c]菲蒽啶生物碱因其对非典型DNA结构的稳定作用而闻名，特别是g -四聚体（G4s）。本研究利用分子荧光和圆二色性（CD）光谱研究了一种罕见的苯并[c]菲蒽啶生物碱fagaronine与几种DNA结构（包括B-DNA、平行、反平行和杂交G4s）的相互作用。研究发现，fagaronine显著提高了所有测试的G4构象的稳定性。此外，核磁共振波谱研究提供了配体与Pu22T14T23所采用的平行G4结构相互作用机制的宝贵信息，Pu22T14T23是在c-myc基因启动子区域内发现的一个突变序列。值得注意的是，与文献中报道的数据相比，fagaronine似乎表现出有史以来对小配体最强的G4热稳定效应之一。

引用次数: 0

Green synthesis, characterization, structural, morphological, antibacterial, and cytotoxicity evaluation of zinc oxide nanoparticles using Fioria vitifolia extract 绿色合成、表征、结构、形态、抗菌和细胞毒性评价的氧化锌纳米颗粒

IF 3.3 3区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Biophysical chemistry

Pub Date : 2025-04-10 DOI: 10.1016/j.bpc.2025.107440

A. Nandhini , P. Anilkumar , J. Jasmin , S. Balamurali

The increasing prevalence of bacterial pathogens diseases and the rise in multidrug resistance highlights the urgent need for new drug delivery systems or novel drug molecules to enhance treatment options. Zinc oxide (ZnO) nanoparticles attracting attention due to their potential in biomedical applications, such as cancer therapy and diagnostics. ZnO is a versatile compound with excellent UV-blocking, anti-inflammatory, and wide-bandgap semiconductor properties. This study focuses on the green synthesis of ZnO nanoparticles using ‘Fioria vitifolia’ leaf extract, as a reducing agent with polyvinylpyrrolidone (PVP) aids in reducing particle size and preventing aggregation, enhancing nanoparticle stability. The ZnO nanoparticles were characterized using various techniques, including X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive X-ray Analysis (EDX), Transmission Electron Microscopy (TEM), Fourier-Transform Infrared Spectroscopy (FTIR), UV–Vis Diffuse Reflectance Spectroscopy (DRS), and Photoluminescence (PL). These analyses confirmed the successful formation of ZnO nanoparticles. The nanoparticles demonstrated strong antimicrobial activity, especially against ‘Enterobacter’, and exhibited significant cytotoxic effects on lung cancer cells (A549), but has low toxicity to standard cells (L929). The IC₅₀ values affirmed their potential as anticancer agents, suggesting their dual promise as antimicrobial and anticancer compounds. The enormous potential of biosynthesized ZnO nanoparticles as biological agents a sustainable substitute for chemically synthesized medications is highlighted in this study. The potential of the nanoparticles in a range of biomedical applications is highlighted by their ecologically friendly manufacturing process as well as their proven antibacterial and anticancer qualities.

细菌性病原体疾病的日益流行和多药耐药性的增加突出表明迫切需要新的药物输送系统或新的药物分子来加强治疗选择。氧化锌纳米颗粒因其在癌症治疗和诊断等生物医学领域的潜在应用而备受关注。ZnO是一种多功能化合物，具有优异的抗紫外线、抗炎和宽禁带半导体特性。本研究主要研究了以“红叶”叶提取物为还原剂，以聚乙烯吡咯烷酮（PVP）为还原剂，绿色合成ZnO纳米颗粒，有助于减小粒径和防止团聚，提高纳米颗粒的稳定性。采用x射线衍射（XRD）、场发射扫描电子显微镜（FESEM）、能量色散x射线分析（EDX）、透射电子显微镜（TEM）、傅里叶变换红外光谱（FTIR）、紫外-可见漫反射光谱（DRS）和光致发光（PL）等多种技术对ZnO纳米颗粒进行了表征。这些分析证实了ZnO纳米颗粒的成功形成。纳米颗粒显示出很强的抗菌活性，特别是对肠杆菌，并对肺癌细胞（A549）显示出显著的细胞毒性作用，但对标准细胞（L929）具有低毒性。IC50值肯定了它们作为抗癌药物的潜力，表明它们作为抗菌和抗癌化合物的双重前景。本研究强调了生物合成ZnO纳米颗粒作为生物制剂的巨大潜力，它是化学合成药物的可持续替代品。纳米颗粒在一系列生物医学应用中的潜力是由其生态友好的制造过程以及经证实的抗菌和抗癌特性所突出的。

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引用次数: 0

Degree–based topological indices, NMR chemical shifts, chemical reactivity, molecular dynamics and DFT analysis of 1,4-Methanoazulene-9-methanol, Decahydro-4,8,8-trimethyl-, [1S-(1α,3aβ,4α,8aβ,9R)] 1,4-Methanoazulene-9-methanol, Decahydro-4,8,8-trimethyl-, [1S-(1α,3aβ,4α,8aβ,9R)] 的基于度的拓扑指数、核磁共振化学位移、化学反应活性、分子动力学和 DFT 分析

IF 3.3 3区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Biophysical chemistry

Pub Date : 2025-04-09 DOI: 10.1016/j.bpc.2025.107442

Jeffrin JA Laura , P. Rajesh , M. Kesavan , E. Dhanalakshmi , S. Kayashrini , M. Prabhaharan

This study aims to comprehensively analyze the structural, vibrational, and electrical characteristics of 11,4-Methanoazulene-9-methanol, decahydro-4,8,8-trimethyl-, [1S-(1α,3aβ,4α,8aβ,9R*)] (MMDT) with a focus on its potential as a therapeutic agent for liver cancer. The compound was isolated from Hybanthus enneaspermus using Soxhlet extraction, followed by Gas Chromatography-Mass Spectrometry (GC–MS) analysis. The structure optimization and vibrational frequency assignments were done using Density Functional Theory (DFT) method with the B3LYP/6–311++G (d, p) basis set. Natural Bond Orbital (NBO) analysis was conducted to explore intramolecular and intermolecular interactions, along with the first-order hyperpolarizability. Electronic properties such as the energy gap and molecular electrostatic potential (MEP), were calculated to anticipate reactive sites for electrophilic and nucleophilic attacks. This is crucial in understanding the compound's reactivity in biological systems. TD-DFT was employed to simulate UV–visible spectra and compared with experimental values. Additionally, the theoretical FTIR spectra were correlated with experimental data, with potential energy distribution (PED%) providing detailed vibrational mode analysis. HOMO and LUMO orbitals were evaluated in the gas phase, revealing key energy parameters. ¹H and ¹³C NMR chemical shifts have been properly assigned using the DFT for structural characterization. QSPR/QSAR analysis is made simpler by determining a few topological indices for the MMDT. This study provides a novel computational framework for MMDT paving the way for faster, cost-effective and the Molecular docking studies revealed stable interactions between MMDT and liver cancer-related receptors, with favourable binding energy values along with Ramachandran plot confirmed the stability of the protein-ligand complex could be a promising candidate for liver cancer treatment.

本研究旨在全面分析11,4-甲烷偶氮烯-9-甲醇，十氢-4,8,8-三甲基- [1S-(1α,3aβ,4α,8aβ,9R*)] （MMDT）的结构、振动和电学特性，重点研究其作为肝癌治疗剂的潜力。采用索氏提取法从棘豆中分离得到该化合物，并采用气相色谱-质谱联用技术对其进行分析。采用密度泛函理论（DFT）方法，以B3LYP/ 6-311 ++G （d, p）基集对结构进行优化和振动频率赋值。利用自然键轨道（NBO）分析了分子内和分子间的相互作用，以及一阶超极化率。通过计算能隙和分子静电势（MEP）等电子性质来预测亲电和亲核攻击的反应位点。这对于理解化合物在生物系统中的反应性至关重要。采用TD-DFT模拟紫外可见光谱，并与实验值进行比较。此外，理论FTIR光谱与实验数据相关联，势能分布（PED%）提供了详细的振动模式分析。在气相中对HOMO和LUMO轨道进行了评估，揭示了关键的能量参数。1H和13C核磁共振化学位移已适当分配使用DFT结构表征。通过确定MMDT的几个拓扑指标，使QSPR/QSAR分析变得更简单。这项研究为MMDT提供了一个新的计算框架，为更快、更经济地实现MMDT铺平了道路。分子对接研究揭示了MMDT与肝癌相关受体之间稳定的相互作用，有利的结合能值和Ramachandran图证实了蛋白质-配体复合物的稳定性，可能是肝癌治疗的有希望的候选者。

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引用次数: 0

Receptor modulated assembly and drug induced disassembly of amyloid beta aggregates at asymmetric neuronal model biomembranes 受体调节的β淀粉样蛋白聚集体在不对称神经元模型生物膜上的组装和药物诱导的拆卸

IF 3.3 3区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Biophysical chemistry

Pub Date : 2025-03-31 DOI: 10.1016/j.bpc.2025.107441

Nirod Kumar Sarangi , Subrata Mondal , Tia E. Keyes

Amyloid peptide non-fibrillar oligomers cause neurotoxicity and may contribute to Alzheimer's disease (AD) pathogenesis. Mounting evidence indicates that Aβ_1–42 oligomers disrupt and remodel neuronal membrane, causing neuronal cell death. The involvement of individual neuronal membrane constituents in real-time Aβ_1–42 aggregate assembly is unclear due to complexity of neuronal cell membrane. We used non-Faradaic electrochemical impedance spectroscopy (EIS) to track monomeric Aβ_1–42 peptide binding and aggregation pathways in real-time in asymmetric micropore suspended lipid bilayer membranes with anionic phospholipids and glycosphingolipids. Anionic DOPC:PIP2 pore suspended membrane showed pore-formation within 2 h of incubation, but peptide insertion occurred over 6 h, with an onset time of ∼6–8 h for peptide aggregation at the membrane surface. Among different gangliosides, peptide binding to GM1- and GM3-containing membranes did not result pore development, but receptor mediated peptide aggregation formation caused membrane admittance to decrease within 2 h. In contrast, partial peptide insertion in the membrane surface increases membrane admittance at GD1a and mixed GSL membranes, arresting aggregation. Time-lapsed AFM imaging at asymmetric solid supported lipid bilayers (aSLBs) corroborated EIS findings, capturing pore-formation and receptor mediated peptide assembly routes. Fluorescence lifetime imaging (FLIM) imaging and spatial resolved single-point fluorescence correlation spectroscopy (FCS) at aSLBs revealed membrane-peptide interaction, assembly, and peptide induced membrane reorganization. Treatment with antidepressants fluoxetine and imipramine therapeutics, in synergy, which are cost-effective and capable of crossing the central nervous system (CNS+), resulted in the disassembly of membrane mediated Aβ_1–42 aggregates, but not fibrils. Overall, the data suggests that membrane-mediated aggregate disassembly at the correct timing of AD progression may halt or reverse amyloid assembly through the use of repurposed drugs.

淀粉样肽非纤维低聚物引起神经毒性，并可能有助于阿尔茨海默病（AD）的发病机制。越来越多的证据表明，Aβ1-42寡聚物破坏和重塑神经元膜，导致神经元细胞死亡。由于神经元细胞膜的复杂性，单个神经元膜成分参与实时Aβ1-42聚集体的组装尚不清楚。利用非法拉第电化学阻抗谱（EIS）实时跟踪了含有阴离子磷脂和鞘糖脂的不对称微孔悬浮脂质双层膜中单体Aβ1-42肽的结合和聚集途径。阴离子DOPC:PIP2孔悬浮膜在2小时内形成孔，但在6小时内发生肽插入，肽在膜表面聚集的开始时间为~ 6 - 8小时。在不同的神经节苷类中，肽与含GM1-和含gm3的膜结合不导致孔发育，但受体介导的肽聚集形成导致膜导纳在2小时内降低。相反，部分肽在膜表面的插入增加了GD1a和混合GSL膜的膜导纳，阻止了聚集。非对称固体支撑脂质双分子层（aSLBs）的延时AFM成像证实了EIS的发现，捕获了孔隙形成和受体介导的肽组装途径。aSLBs的荧光寿命成像（FLIM）和空间分辨单点荧光相关光谱（FCS）揭示了膜-肽的相互作用、组装和肽诱导的膜重组。抗抑郁药氟西汀和丙咪嗪治疗协同作用，具有成本效益，能够穿过中枢神经系统（CNS+），导致膜介导的Aβ1-42聚集体的分解，但不破坏原纤维。总的来说，这些数据表明，在AD进展的正确时间，膜介导的聚集体分解可以通过使用重新定位的药物来停止或逆转淀粉样蛋白的组装。

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引用次数: 0

Interaction of Myrsinoic acid a with biomembrane models: Differential effects on DPPC and DPPS properties revealed by surface rheology and vibrational spectroscopy 蜜桃酸a与生物膜模型的相互作用：通过表面流变学和振动光谱揭示对DPPC和DPPS性能的差异影响

IF 3.3 3区生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY

Biophysical chemistry

Pub Date : 2025-03-28 DOI: 10.1016/j.bpc.2025.107439

Ana Gabrieli A. dos Santos, Fernando Cassas, Kevin Figueiredo dos Santos, Livia Soman de Medeiros, Thiago André Moura Veiga, Luciano Caseli

This study investigates the interactions of Myrsinoic acid A, a natural compound with reported anti-inflammatory and antitumor properties, with lipid monolayers composed of dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylserine (DPPS). Utilizing tensiometry, polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS), Brewster Angle Microscopy (BAM), and surface rheology, we analyzed how Myrsinoic acid A affects the structural and mechanical properties of these lipid systems. The PM-IRRAS spectra revealed that Myrsinoic acid A induced disorder in the DPPC monolayer, shifting CH₂ asymmetric stretching peaks and decreasing packing order, while DPPS remained structurally stable. Surface rheology measurements showed reduced elasticity in both lipids, with differential effects on viscosity: a decrease for DPPC and an increase for DPPS, indicating varied molecular interactions. BAM images confirmed that DPPC maintained a homogeneous morphology, while DPPS displayed aggregate formation, suggesting distinct lipid-drug interactions. These findings highlight the importance of lipid composition in modulating the effects of Myrsinoic acid A on membrane properties, providing insights into its potential therapeutic applications in targeting tumorigenic versus non-tumorigenic cells.

本研究研究了具有抗炎和抗肿瘤特性的天然化合物桃金酸A与双棕榈酰磷脂酰胆碱（DPPC）和双棕榈酰磷脂酰丝氨酸（DPPS）组成的脂质单分子膜的相互作用。利用张力测定法、偏振调制红外反射吸收光谱（PM-IRRAS）、Brewster角度显微镜（BAM）和表面流变学，我们分析了桃金酸A如何影响这些脂质系统的结构和力学性能。PM-IRRAS光谱显示，桃金酸A导致DPPC单层结构紊乱，ch2不对称拉伸峰移位，堆积顺序降低，而DPPS结构保持稳定。表面流变学测量表明，两种脂类的弹性都降低了，对粘度的影响不同：DPPC降低，DPPS增加，表明不同的分子相互作用。BAM图像证实DPPC保持均匀形态，而DPPS显示聚集形成，表明明显的脂质-药物相互作用。这些发现强调了脂质组成在调节桃金酸A对膜特性的影响中的重要性，为其针对致瘤细胞和非致瘤细胞的潜在治疗应用提供了见解。

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