Anti-aggregating Agents Research Articles

Chelating Properties of N6O-Donors Toward Cu(II) Ions: Speciation in Aqueous Environments and Catalytic Activity of the Dinuclear Complexes

This study focuses on the use of three isostructural N6O donor ligands, specifically known to form complexes with copper ions, to chelate Cu(II) from aqueous solutions. The corresponding Cu(II) complexes feature a dinuclear copper core mimicking the active site of natural superoxide dismutase (SOD) enzymes while also creating a coordination environment favorable for catalase (CAT) activity, being thus appealing as catalytic antioxidant systems. Given the critical role of copper dysregulation in the pathophysiology of Alzheimer’s disease (AD), these complexes may help mitigate the harmful effects of free Cu(II) ions: the goal is to transform copper’s reactive oxygen species (ROS)-generating properties into beneficial ROS-scavenging action. This study investigates the speciation, chelating efficiency, and metal selectivity of these ligands, as well as the antioxidant activity of the resulting complexes under aqueous and physiologically relevant conditions. Additionally, the ligands, equipped with functional groups for attaching targeting moieties, are conjugated with a small peptide that may act as an anti-aggregating agent of β-amyloid peptides, aiming to develop a multifunctional therapeutic strategy against Alzheimer’s disease.

Doxorubicin as a Drug Repurposing for Disruption of α-Chymotrypsinogen-A Aggregates.

Protein conformation is affected by interaction of several small molecules resulting either stabilization or disruption depending on the nature of the molecules. In our earlier communication, Hg2+ was known to disrupt the native structure of α-Cgn A leading to aggregation (Ansari, N.K., Rais, A. & Naeem, A. Methotrexate for Drug Repurposing as an Anti-Aggregatory Agent to Mercuric Treated α-Chymotrypsinogen-A. Protein J (2024). https://doi.org/10.1007/s10930-024-10187-z ). Accumulation of β-rich aggregates in the living system is found to be linked with copious number of disorders. Here, we have investigated the effect of varying concentration of doxorubicin (DOX) i.e. 0-100 µM on the preformed aggregates of α-Cgn A upon incubation with 120 µM Hg2+. The decrease in the intrinsic fluorescence and enzyme activity with respect to increase in the Hg2+ concentration substantiate the formation of aggregates. The DOX showed the dose dependent decrease in the ThT fluorescence, turbidity and RLS measurements endorsing the dissolution of aggregates which were consistent with red shift in ANS, confirming the breakdown of aggregates. The α-Cgn A has 30% α-helical content which decreases to 3% in presence of Hg2+. DOX increased the α-helicity to 28% confirming its anti-aggregatory potential. The SEM validates the formation of aggregates with Hg2+ and their dissolution upon incubation with the DOX. Hemolysis assay checked the cytotoxicity of α-Cgn A aggregates. Docking revealed that the DOX interacted Lys203, Cys201, Cys136, Ser159, Leu10, Trp207, Val137 and Thr134 of α-Cgn A through hydrophobic interactions and Gly133, Thr135 and Lys202 forms hydrogen bonds.

Amylovis-201 is a new dual-target ligand, acting as an anti-amyloidogenic compound and a potent agonist of the σ1 chaperone protein

The aggregation of Amyloid-β (Aβ) peptides is associated with neurodegeneration in Alzheimer's disease (AD). We previously identified novel naphtalene derivatives, including the lead compound Amylovis-201, able to form thermodynamically stable complexes with Aβ species, peptides and fibrils. As the drug showed a chemical scaffold coherent for an effective interaction with the σ1 receptor chaperone and as σ1 agonists are currently developed as potent neuroprotectants in AD, we investigated the pharmacological action of Amylovis-201 on the σ1 receptor. We report that Amylovis-201 is a potent σ1 agonist by several in silico, in vitro and in vivo assays and that its anti-amnesic and neuroprotective effects involve a pharmacological action at σ1 receptors. Furthermore, we show for the first time that classical σ1 receptor agonist (PRE-084), and antagonist (NE-100) are able to interact and disaggregate Aβ25–35 fibrils. Interestingly, Amylovis-201 was the only compound inhibiting Aβ25–35 aggregates formation. Our results therefore highlight a dual action of Amylovis-201 as anti-aggregating agent and σ1 receptor agonist that could be highly effective in long-term treatment against neurodegeneration in AD.

Methotrexate for Drug Repurposing as an Anti-Aggregatory Agent to Mercuric Treated α-Chymotrypsinogen-A.

Protein aggregation is related to numerous pathological conditions like Alzheimer's and Parkinson's disease. In our study, we have shown that an already existing FDA-approved drug; methotrexate (MTX) can be reprofiled on preformed α-chymotrypsinogen A (α-Cgn A) aggregates. The zymogen showed formation of aggregates upon interaction with mercuric ions, with increasing concentration of Hg2Cl2 (0-150 µM). The hike in ThT and ANS fluorescence concomitant with blue shift, bathochromic shift and the hyperchromic effect in the CR absorbance, RLS and turbidity measurements, substantiate the zymogen β-rich aggregate formation. The secondary structural alterations of α- Cgn A as analyzed by CD measurements, FTIR and Raman spectra showed the transformation of native β-barrel conformation to β-inter-molecular rich aggregates. The native α- Cgn A have about 30% α-helical content which was found to be about 3% in presence of mercuric ions suggesting the formation of aggregates. The amorphous aggregates were visualized by SEM. On incubation of Hg2Cl2 treated α- Cgn A with increasing concentration of the MTX resulted in reversing aggregates to the native-like structure. These results were supported by remarkable decrease in ThT and ANS fluorescence intensities and CR absorbance and also consistent with CD, FTIR, and Raman spectroscopy data. MTX was found to increase the α-helical content of the zymogen from 3 to 15% proposing that drug is efficient in disrupting the β-inter-molecular rich aggregates and reverting it to native like structure. The SEM images are in accordance with CD data showing the disintegration of aggregates. The most effective concentration of the drug was found to be 120 µM. Molecular docking analysis showed that MTX molecule was surrounded by the hydrophobic residues including Phe39, His40, Arg145, Tyr146, Thr151, Gly193, Ser195, and Gly216 and conventional hydrogen bonds, including Gln73 (bond length: 2.67Å), Gly142 (2.59Å), Thr144 (2.81Å), Asn150 (2.73Å), Asp153 (2.71Å), and Cys191 (2.53Å). This investigation will help to find the use of already existing drugs to cure protein misfolding-related abnormalities.

Molecular Insights into the Inhibition and Disaggregation Effects of EGCG on Aβ40 and Aβ42 Cofibrillation.

The misfolding and aggregation of amyloid-β (Aβ) peptides play a pivotal role in the pathogenesis of Alzheimer's disease (AD). Aβ40 and Aβ42, the two primary isoforms of Aβ, can not only self-aggregate into homogeneous aggregates but also coaggregate to form mixed fibrils. Epigallocatechin-3-gallate (EGCG), a prominent tea polyphenol, has shown the capability to prevent the self-aggregation of Aβ40 and Aβ42 peptides and disaggregate their homogeneous fibrils. However, its effects on the cofibrillation of Aβ40 and Aβ42 have not yet been explored. Here, we employed molecular dynamic simulations to investigate the effects of EGCG on the coaggregation of Aβ40 and Aβ42, as well as on their mixed fibril. Our findings indicated that EGCG effectively inhibits the codimerization of Aβ40 and Aβ42 primarily by impeding the interchain interaction between the two isoforms. The key binding sites for EGCG on Aβ40 and Aβ42 are the polar residues and aromatic residues, engaging in hydrogen-bond , π-π, and cation-π interactions with EGCG. Additionally, EGCG disaggregates the Aβ40-Aβ42 mixed fibril by reducing its long-range interaction through similar binding sites and interactions as those between EGCG and Aβ40-Aβ42 heterodimers. Our research reveals the comprehensive inhibition and disaggregation effects of EGCG on the cofibrillation of Aβ isoforms, which provides further support for the development of EGCG as an effective antiaggregation agent for AD.

Effect of Resveratrol as an adjunct to Scaling and Root Planing in Chronic Periodontitis Patients with Type 2 Diabetes

Resveratrol is a polyphenol stilbene found in red wine, red grape skins and other plants such as mulberries and peanuts. Resveratrol exhibits a wide range of beneficial properties such as anticarcinogenic agent, platelet antiaggregation agent, antiallergenic, antioxidant, and anti- inflammatory agent. Material and Methods A total of 30 patients diagnosed as chronic periodontitis with diabetes were included in this study. and divided into 2 groups, Group-I(SRP+ resveratrol, n=15) & Group-II (SRP alone, n=15). Resveratrol capsules once daily were prescribed for 3 weeks. Plaque index(PI), Gingival index (MSBI), probing pocket depth (PPD), clinical attachment level (CAL) and serum venous blood sample collection for HbA1c levels. All the parameters were recorded at baseline and at 3 months post-operative. Results All the parameters in both Group I and Group II showed statistically significant (P≤0.001) reduction from baseline to 3 months. improvement from baseline to 3 months. When compared between the two groups, a significant difference was observed in Group I in relation with PI and HbA1c levels at 3 months post-operatively. Conclusion Resveratrol as adjunctive to SRP has shown reduction in periodontal parameters in chronic periodontitis along with improved glycemic control in diabetes patients. Key Words: Diabetes, Glycated hemoglobin levels, Resveratrol, Scaling and root planing

Aromatic vs alicyclic: Hydrophobicity of the ionic liquid on protein stability and fibril formation

Ionic liquids (ILs) are environment-friendly solvents with potential applications in biochemical reactions and as pharmaceutical ingredients. They are used to stabilize proteins and act as anti-aggregation agents in which the hydrophobic effect of ILs is suggested to have a primary role. To understand the differences in the effect of aromatic and alicyclic cations of ILs on thermal stability and fibrillation propensity of proteins, the effect of two alicyclic (butyl-1-methylpyrrolidinium and butyl-1-methylpiperidinium) and two aromatic (butyl-4-methylpyridinium and butyl-3-methylimidazolium) ILs on lysozyme was investigated by spectroscopy, densitometry, and molecular dynamics simulation. The results suggest that all the ILs switch the fibrillation pathway from nucleation-independent to nucleation-dependent mechanism at ≥200 mM. The fibrillation is slowed down by 28–35-fold in 500 mM of ILs, exceptionally pyrrolidinium-IL delays the fibrillation by ∼70-fold. All the ILs destabilize the protein during thermal denaturation. Though in all cases the unfolding is enthalpy-driven, pyridinium-IL at higher concentrations exhibits an entropy-driven unfolding effect. The volumetric analysis shows a higher thermal expansion coefficient for Lyz in pyridinium-IL which might be due to the increased internal cavity volume of the protein upon binding of the IL. These results corroborate with the computational studies that the preferential interaction coefficient of aromatic-ILs is more, particularly at a higher concentration (200 mM). Four preferable binding sites for ILs on the protein could be identified that includes the amyloidogenic regions, β-hairpin and the hydrophobic cluster 5. Also, the ILs are found to preferably interact with the protein through their alicyclic/aromatic ring and alkyl sidechain. These results suggest that the binding of ILs to the amyloidogenic region inhibits the fibril formation which has a similar effect for both alicyclic and aromatic ILs whereas aromatic-ILs show a larger destabilization effect than alicyclic-ILs at higher concentrations.

Research and Evaluation of Foam-Drainage Corrosion-Inhibition Hydrate Anti-Aggregation Integrated Agent

In natural gas exploitation, foam drainage, corrosion inhibition and hydrate inhibition of wellbore fluid are conventional operations. However, there is often a problem where multiple chemical agents cannot be effectively used together and can only be used separately, resulting in complex production processes. In this study, the final integrated formulation was determined: 0.1% sodium alpha-olefin sulfonate (AOST) + 0.3% dodecyl dimethyl betaine (BS-12) + 0.3% sodium lignosulfonate + 0.5% hydrazine hydrate. The minimum tension of the integrated agent could be reduced to 23.5 mN/m. The initial foaming height of the integrated agent was 21.5 cm at 65 °C, the liquid-carrying capacity was 143 mL, and the liquid-carrying rate reached 71.5%. The maximum corrosion depth also decreased from 11.52 µm without the addition of hydrazine hydrate, gradually decreasing to 5.24 µm as the concentration of hydrazine hydrate increased. After adding an integrated agent, the growth rate of hydrates was slow and aggregation did not easily occur, and the formation temperature was also more demanding. Therefore, the integrated agent has a inhibitory effect on the formation of hydrates and has a good anti-aggregation effect. From the observation of the microstructure, the emulsion is an oil-in-water type, and the integrated agent adsorbs at the oil–water interface, preventing the dispersed water droplets in the oil phase from coalescing in one place. The oil-in-water type emulsion is more likely to improve the performance of the natural gas hydrate anti-aggregation agent.

Evidence of enhanced inhibitory potential of Ferulic Acid Ethyl Ester towards modulating fibrillation and disassembling insulin fibrils

The conversion of native conformation of protein into proteotoxic insoluble entities is not only confined to the protein misfolding diseases(PMDs) but also associated with pharmaceutically important proteins like insulin during the process of manufacturing/administration. Also all the neurodegenerative diseases are marked with increased level of oxidative stress. Thus finding anti-aggregation agents having anti-oxidant potential is utmost important to combat these complications. Herein, we performed biophysical, computational and imaging techniques to decipher the anti-aggregation propensity of a naturally occurring hydroxycinnamate- Ferulic acid ethyl ester(FAEE) that can cross blood brain barrier. Rayleigh light scattering(RLS) measurements, dye binding assays, Circular dichroism(CD) and Dynamic light scattering(DLS) measurements confirmed the efficient inhibition of insulin fibrillation by FAEE. The Stern-Volmer plot analysis reflected both the static and dynamic quenching mechanism of insulin by FAEE. Molecular docking and simulations results showed that FAEE bind and stabilizes the monomeric state of insulin with binding energy −6.3 kcal/mol. Moreover, the inhibiting effect of FAEE on the elongation phase of onward fibrillation in addition with triggering its fibril disassembling capability was also investigated. Both the stabilization of the protein structure and the restriction of monomers recruitment necessary for the fibrillar growth acts synergistically in providing FAEE its anti-aggregation effect. Appearance of significantly lesser and shortened fibrils in FAEE presence was depicted by transmission electron microscopy. Overall, our finding establishes for the first time the anti-amyloidogenic role of lipophilic FAEE which can cross blood brain barrier. These findings may inspire the development of FAEE based formulations that could possibly treat amyloid-related diseases.

Fluorescence of D-Glucose-Derived Carbon Dots: Effect of Process Parameters

The aim of this study was to synthesize highly fluorescent carbon dots (CDs) from glucose using a microwave hydrothermal method. It explored the impact of glucose concentration, process time, molar ratio of KH2PO4 to glucose, and homogenization time on the resulting CDs, employing a fractional plan 3(k-1) with four independent parameters for twenty-seven synthesis. Results showed that longer process times at 200°C increased the fluorescence intensity of the CDs. The molar ratio of KH2PO4 to glucose, glucose concentration, and process time significantly influenced fluorescence. Homogenization was crucial for obtaining small particles, though an anti-aggregation agent might still be needed. UV-vis spectroscopy, spectrofluorimetry, and DLS were used to analyze the synthesized CDs. The UV-vis absorption maxima were observed around 230 nm and 282 nm, with peak shifts at different excitation wavelengths. Out of the twenty-seven samples, six CDs samples were identified to be below 10 nm and a total of twelve below 50 nm. Analyzing the results, the study concluded that the CDs possess strong fluorescence and are suitable for diverse applications. For enhanced fluorescence, longer process times at 200°C and the use of KH2PO4 were recommended, while shorter processes were preferred for obtaining smaller particles. Hierarchical clustering, the k-means method, Pareto charts, and profiles for predicted values and desirability were used to analyze the results. It was confirmed that higher fluorescence is favored by longer process time at 200°C and the use of KH2PO4. In order to obtain smaller particles, shorter processes should be used.

Metal-Complexes Bearing Releasable CO Differently Modulate Amyloid Aggregation.

Neurodegenerative diseases are often associated with an uncontrolled amyloid aggregation. Hence, many studies are oriented to discover new compounds that are able to modulate self-recognition mechanisms of proteins involved in the development of these pathologies. Herein, three metal-complexes able to release carbon monoxide (CORMs) were analyzed for their ability to affect the self-aggregation of the amyloidogenic fragment of nucleophosmin 1, corresponding to the second helix of the three-helix bundle located in the C-terminal domain of the protein, i.e., NPM1264-277, peptide. These complexes were two cymantrenes coordinated to the nucleobase adenine (Cym-Ade) and to the antibiotic ciprofloxacin (Cym-Cipro) and a Re(I)-compound containing 1,10-phenanthroline and 3-CCCH2NHCOCH2CH2-6-bromo-chromone as ligands (Re-Flavo). Thioflavin T (ThT) assay, UV-vis absorption and fluorescence spectroscopies, scanning electron microscopy (SEM), and electrospray ionization mass spectrometry (ESI-MS) indicated that the three compounds have different effects on the peptide aggregation. Cym-Ade and Cym-Cipro act as aggregating agents. Cym-Ade induces the formation of NPM1264-277 fibers longer and stiffer than that formed by NPM1264-277 alone; irradiation of complexes speeds the formation of fibers that are more flexible and thicker than those found without irradiation. Cym-Cipro induces the formation of longer fibers, although slightly thinner in diameter. Conversely, Re-Flavo acts as an antiaggregating agent. Overall, these results indicate that metal-based CORMs with diverse structural features can have a different effect on the formation of amyloid fibers. A proper choice of ligands attached to metal can allow the development of metal-based drugs with potential application as antiamyloidogenic agents.

The role of frailty score in early surgical treatment of elderly cholecystitis patients

Objectives: The average life expectancy is increasing all over the world, and as a result, the number of elderly patients is increasing. Acute cholecystitis is one of the most common diseases requiring emergency surgical treatment in the elderly. In the literature, it has been reported that in the treatment of elderly patients with acute cholecystitis, physicians do not fully comply with the current literature recommendations due to some concerns and do not apply surgical treatment in the early period. The concept of frailty, which has come to the fore in geriatric assessment today, provides objective information about the general health status of the patient. In our study, the role of frailty assessment in the decision made regarding the early surgery in elderly patients with acute cholecystitis treated in our hospital was investigated. Methods: In our study, the clinical features, comorbidities, American Society of Anesthesiologists (ASA) scores, Canadian Study of Health and Aging (CSHA) frailty scale, treatment modalities and prognosis of patients over the age of 65 who were treated with the diagnosis of acute cholecystitis between January 2018 and January 2021 were evaluated retrospectively. Results: Of the 182 patients included in the study, 24 (13.2%) were found to be frail. It was observed that the mean age and multi-morbidity were higher in the frail group (p < 0.001). It was observed that the mean C-reactive protein and leukocyte values, which are inflammatory mediators, increased in both groups, both fragile and non-fragile, and complicated cholecystitis accompanied by cholangitis or pancreatitis was observed in a total of 64 (35.16%) patients. There were 57 (31.3%) patients using anticoagulant or antiaggregant agents. The patients were most frequently treated with medical treatment (n = 108; 59.3%), the other treatment methods were early surgery ( (n = 46; 25.3%), endoscopic retrograde cholangiopancreatography (n = 22; 12.1%) and percutaneous cholecystostomy (n = 11; 6.0%). Surgical treatment was more common in ASA I and II patients, and percutaneous cholecystostomy was more common in frail patients (p < 0.001). There were 20 (14.70%) patients who were re-admitted to the hospital and 6 (3.29%) patients ended up with mortality. No statistical relationship could be demonstrated between these conditions and frailty (p > 0.05). Conclusions: In the treatment of the elderly cholecystitis patients, early surgical treatment is the most favorable treatment method in order to reduce re-admission and prevent possible complications. However, we think that a detailed geriatric evaluation should be made in a multidisciplinary manner for the decision making regarding the of surgical treatment of elderly patients, and frailty evaluation should also be made in this context.

Do Patients With Arterial Occlusive Disease of Different Etiologies Benefit Equally From Cilostazol?

Cilostazol is a guideline-recommended drug that improves intermittent claudication and quality of life in patients with chronic atherosclerotic peripheral arterial disease. The drug is used for most etiologies of arterial occlusive diseases in clinical practice. This study aimed to evaluate whether patients benefit equally from cilostazol regardless of etiology. Patients on cilostazol were divided into 4 groups according to arterial occlusive disease etiology: (1) atherosclerosis, (2) diabetic angiopathy, (3) embolism/thrombosis, and (4) Buerger disease. Patients' maximum walking distance, ankle-brachial index score and distal tissue oxygen saturation (Sto2), clinical improvement onset time, ability to reach maximum benefit time, vascular surgeries, and wounds were compared before they started cilostazol and after 12 months. Results were evaluated at a statistical significance of P < .05. In 194 patients, 307 target extremities were evaluated in the 4 disease groups. After cilostazol use, maximum walking distance, ankle-brachial index score, and distal Sto2 increased significantly in all groups (P < .001), but distal Sto2 in the diabetic angiopathy and Buerger disease groups was significantly lower than in the atherosclerosis group (P < .001). Ankle-brachial index and distal Sto2 differences in the Buerger disease group were significantly lower (both P < .001). The vascular surgery counts decreased significantly in the atherosclerosis and embolism/thrombosis groups (P = .019 and P = .004, respectively). Patients with nonatherosclerotic arterial occlusive disease also benefit from cilostazol, but patients with Buerger disease or diabetic angiopathy seem to benefit less. Combining cilostazol with anticoagulant or antiaggregant agents and closer monitoring of these patients may produce better results.

Nanoscale insights into the local structural rearrangements of amyloid-β induced by bexarotene.

A better understanding of the abnormal protein aggregation and the effect of anti-aggregation agents on the fibrillation pathways and the secondary structure of aggregates can determine strategies for the early treatment of dementia. Herein, we present a combination of experimental and theoretical studies providing new insights into the influence of the anti-aggregation drug bexarotene on the secondary structure of individual amyloid-β aggregates and its primary aggregation. The molecular rearrangements and the spatial distribution of β-sheets within individual aggregates were monitored at the nanoscale with infrared nanospectroscopy. We observed that bexarotene limits the parallel β-sheets formation, known to be highly abundant in fibrils at later phases of the amyloid-β aggregation composed of in-register cross-β structure. Moreover, we applied molecular dynamics to provide molecular-level insights into the investigated system. Both theoretical and experimental results revealed that bexarotene slows down the protein aggregation process via steric effects, largely prohibiting the antiparallel to parallel β-sheet rearrangement. We also found that bexarotene interacts not only via the single hydrogen bond formation with the peptide backbone but also with the amino acid side residue via a hydrophobic effect. The studied model of the drug-amyloid-β interaction contributes to a better understanding of the inhibition mechanism of the amyloid-β aggregation by the small molecule drugs. However, our nanoscale findings need to meet in vivo research requiring different analytical approaches.

Biotechnological techniques for intensification of protein extraction from the porcine pancreas

Processing of secondary products after slaughter of farm animals is in demand. The pancreas is a rich source of bioactive protein substances, effective extraction of which is a serious problem today due to their aggregation. The aim of the work was to assess the extractivity of protein substances of the porcine pancreas using sodium chloride, trehalose, arginine, and combination of glycine and proline. The protein concentration was determined in the obtained extracts by the biuret reaction and their protein composition was assessed by densitometry of two-dimensional electropherograms using software ImageMaster™ 2D Platinum powered by Melanie 8.0. The results showed a positive effect of anti-aggregation agents on the release of protein substances into a solution. The highest protein concentration (33.36±0.64 g/l) was observed when adding 1М L-arginine; however, it was conditioned mainly by an increase in the content of three major protein fractions rather than by diversity of the protein composition. In general, the use of 0.9% NaCl as an extractive agent was quite effective, but selectivity to certain protein groups was observed for anti-aggregation agents such as sodium chloride, trehalose, arginine, glycine and proline, as well as their combination. The obtained results are important for intensifying extraction of protein substances including target ones with the subsequent application in different fields.

A YSK-Type Dehydrin from Nicotiana tabacum Enhanced Copper Tolerance in Escherichia coli

Copper is an essential micronutrient for the maintenance of normal cell function but is toxic in excess. Dehydrins are group two late embryogenesis abundant proteins, which facilitate plant survival in harsh environmental conditions. Here, a YSK-type dehydrin, NtDhn17, was cloned from Nicotiana tabacum under copper toxicity and characterized using a heterologous expression system and in vitro or in vivo experiments and exhibited characteristics of intrinsic disorder during in vitro analyses. Heterologous expression of NtDHN17 enhanced the tolerance of E. coli to various metals, osmotic, and oxidative stress. NtDHN17 showed no Cu2+-binding properties in vivo or in vitro, indicating that metal ion binding is not universal among dehydrins. In vitro and in vivo experiments suggested that NtDHN17 behaved as a potent anti-aggregation agent providing strong protection to aggregated proteins induced by excess copper ions, an effect dependent on the K-segment but not on the Y- or S-segments. In summary, the protective role of NtDHN17 towards E. coli under conditions of copper toxicity may be related to anti-aggregation ability rather than its acting as an ion scavenger, which might be a valuable target for the genetic improvement of resistance to heavy metal stresses in plants.

Inhibition of β-Amyloid Aggregation in Alzheimer's Disease: The Key Role of (Pro)electrophilic Warheads.

Catechols have been largely investigated as antiaggregating agents toward β-amyloid peptide. Herein, as a follow up of a previous series of hydroxycinnamic derivatives, we synthesized a small set of dihydroxy isomers for exploring the role of the reciprocal position of the two hydroxyl functions at a molecular level. Para- and ortho-derivatives effectively reduced amyloid fibrillization, while the meta-analogue was devoid of any activity in this respect. Electrochemical analyses showed that the antiaggregating potency correlates with the oxidation potential, hence indicating the proelectrophilic character as a prerequisite for activity. Interestingly, mass spectrometry studies and quantum mechanical calculations revealed different modes of action for active para- and ortho-derivatives, involving covalent or noncovalent interactions with β-amyloid. The distinctive mode of action is also translated into a different cytotoxicity profile. This work clearly shows how apparently minimal structural modifications can completely change the compound behavior and generate alternative mechanisms of action of proelectrophilic chemical probes.

Molecular Docking, Dynamics, and WaterSwap Analysis to Identify Anti-aggregating Agents of Insulin and IFN-β.

There are several challenges in the development, and formulation of biologics, particularly concerning their physical stabilities. The self-assembly of peptides like human insulin and interferon beta (IFN-β) has potential to form aggregates in pharmaceutical formulation. Therefore, it is a significant problem in the manufacturing, storage, and delivery of insulin and IFN-β formulations. Amino acids as aggregation suppressing additives have been used to stabilize proteins during manufacturing and storage. Several changes to the B chain's C-terminus have been proposed in an attempt to improve insulin formulation. The core segments of the A and B chains (SLYQLENY and LVEALYLV) have recently been identified as sheet-forming areas, and their microcrystalline structures have been exploited to construct a high-resolution insulin amyloid fibril model. Here, we have chosen twenty-one amino acids to develop as additives in rendering the insulin and IFN-β aggregations. Thereafter, integrated molecular docking studies of single layer monomers of full-length insulin and IFN-β have been performed to identify structural elements (amino acids) that can act as disaggregating agents. The stability of the best-docked amino acid complexes was judged using molecular dynamics studies. Finally, phenylalanine was identified as a disaggregation agent for insulin, and lysine, tyrosine, phenylalanine, and tryptophan were identified as disaggregation agents for IFN-β from the molecular dynamics study. These findings may open a novel proposal to explore further in vitro studies to increase the stability of the insulin and IFN-β formulation.

Decoding Conformational Imprint of Convoluted Molecular Interactions Between Prenylflavonoids and Aggregated Amyloid-Beta42 Peptide Causing Alzheimer's Disease.

Protein misfolding occurs due to the loss of native protein structure and adopts an abnormal structure, wherein the misfolded proteins accumulate and form aggregates, which result in the formation of amyloid fibrils that are associated with neurodegenerative diseases. Amyloid beta (Aβ42) aggregation or amyloidosis is contemplated as a unique hallmark characteristic of Alzheimer’s disease (AD). Due to aberrant accrual and aggregation of Aβ42 in extracellular space, the formation of senile plaques is found in AD patients. These senile plaques occur usually in the cognitive and memory region of the brain, enfeebles neurodegeneration, hinders the signaling between synapse, and disrupts neuronal functioning. In recent years, herbal compounds are identified and characterized for their potential as Aβ42 inhibitors. Thus, understanding their structure and molecular mechanics can provide an incredible finding in AD therapeutics. To describe the structure-based molecular studies in the rational designing of drugs against amyloid fibrils, we examined various herbal compounds that belong to prenylflavonoids. The present study characterizes the trends we identified at molecular docking studies and dynamics simulation where we observed stronger binding orientation of bavachalcone, bavachin, and neobavaisoflavone with the amyloid-beta (Aβ42) fibril structure. Hence, we could postulate that these herbal compounds could be potential inhibitors of Aβ42 fibrils; these anti-aggregation agents need to be considered in treating AD.

Vasoprotective Actions of Nitroxyl (HNO): A Story of Sibling Rivalry.

Nitroxyl (HNO), the 1 electron-reduced and protonated form of nitric oxide (NO•), has emerged as a nitrogen oxide with a suite of vasoprotective properties and therapeutic advantages over its redox sibling. Although HNO has garnered much attention due to its cardioprotective actions in heart failure, its ability to modulate vascular function, without the limitations of tolerance development and NO• resistance, is desirable in the treatment of vascular disease. HNO serves as a potent vasodilator and antiaggregatory agent and has an ability to limit vascular inflammation and reactive oxygen species generation. In addition, its resistance to scavenging by reactive oxygen species and ability to target distinct vascular signaling pathways (Kv, KATP, and calcitonin gene-related peptide) contribute to its preserved efficacy in hypertension, diabetes, and hypercholesterolemia. In this review, the vasoprotective actions of HNO will be compared with those of NO•, and the therapeutic utility of HNO donors in the treatment of angina, acute cardiovascular emergencies, and chronic vascular disease are discussed.