Development of novel 18F-labelled FAP-targeting tracers with improved pharmacokinetics: From preclinical optimization to clinical translation.

This study investigated the locations of amino acid modifications within two major human hair keratins (Type I K31 and Type II K85) with probable implications for protein and hair structural component integrity. The particular focus was on cysteine modifications that disrupt intra-protein and inter-protein disulphide bonds. Human hair was exposed to accelerated, sequential heat or UV treatments, simulating effects resulting from the use of heated styling tools and environmental exposure over a time frame approximating one year. The proteins were extracted and detected using LC-MS/MS and identified by matching to protein databases. The sites of disulphide-disrupting amino acid residue modifications were mapped to known structural domains of the keratins. Disulphide bond-disrupting cysteine modifications (formation of cysteic acid and dehydroalanine) arose in K31 and K85 after treatments with UV and with heat. These modifications were mapped to both the relatively amorphous (head) regions of the keratins, which bind with keratin-associated proteins, and the more structured coil regions, which bind to other keratins. These data provide confirmation that heat- and UV-induced disulphide bond disruption resulted in post-translational modifications that are crucial for secondary structural interactions, the loss of which has the potential to affect the loss of structural integrity observed in human hair after the use of repeated styling processes or prolonged weathering from sunlight exposure.

Differences in utilization and metabolism of Ulva lactuca polysaccharide by human gut Bacteroides species in the in vitro fermentation.

Microglia, key immune cells in the brain, play a pivotal role in brain homeostasis and immune responses. Emerging evidence suggests their critical involvement in Alzheimer's disease (AD) pathogenesis and propagation. The propagation of AD pathology is related to the extracellular matrix of microglia, including extracellular vesicles (EV). Recently, microglia-derived EVs are implicated in inflammatory processes and neuronal death. This study aimed to extensively profile and propose the metabolic role of microglial EVs in AD. Accordingly, we determined the significant alterations of the EV metabolome associated with the metabolites in primary microglial cells. Aβ exposure induced significant metabolic alteration of 39, 18, and 28 metabolites in microglial cells, cultured media, and EVs, respectively. Aβ exposure triggered common alteration of key metabolic pathways between microglial cells and EVs, including purine, amino acid, and fatty acid metabolisms. While most of the common metabolites showed the same directional changes among the microglial system, N-acetyl aspartic acid displayed the opposite directional change in EVs. N-acetyl aspartic acid decreased 2.3-fold and twofold in microglial cells and media, respectively, but increased 3.5-fold in EVs under Aβ exposure. Moreover, mediation analysis proposed key EV metabolites that were directly affected by the metabolic dysregulation of Aβ-exposed microglial cells. The up-regulation of cysteic acid in EVs was mediated by up-regulated IMP in microglial cells. The down-regulation of 1-16:0-lysoPE in EVs was mediated by stearoyl-L-carnitine in microglial cells. Our study sheds new light on the role of microglia and EVs in neurodegenerative diseases, offering promising avenues for future therapeutic interventions.

The SARS-CoV-2 Spike (S) protein plays a central role in viral entry into host cells, making it a key target for therapeutic interventions. Oxidative stress, often triggered during viral infections, can cause oxidation of cysteine in this protein. Here we investigate the impact of cysteine oxidation, specifically the formation of cysteic acid, on the conformational dynamics of the SARS-CoV-2 S protein using atomistic simulations. In particular, we examine how cysteine oxidation influences the transitions of the S protein’s receptor-binding domain (RBD) between “down” (inaccessible) and “up” (accessible) states, which are critical for host cell receptor engagement. Using solvent-accessible surface area (SASA) analysis, we identify key cysteine residues susceptible to oxidation. The results of targeted molecular dynamics (TMD) and umbrella sampling (US) simulations reveal that oxidation reduces the energy barrier for RBD transitions by approximately 30 kJ mol−1, facilitating conformational changes and potentially enhancing viral infectivity. Furthermore, we analyze the interactions between oxidized cysteine residues and glycans, as well as alterations in hydrogen bonds and salt bridges. Our results show that oxidation disrupts normal RBD dynamics, influencing the energy landscape of conformational transitions. Our work provides novel insights into the role of cysteine oxidation in modulating the structural dynamics of the SARS-CoV-2 S protein, highlighting potential targets for antiviral strategies aimed at reducing oxidative stress or modifying post-translational changes. These findings contribute to a deeper understanding of viral infectivity and pathogenesis under oxidative conditions.

ObjectiveThe first objective of this study is to compare two molecular markers, cysteic acid and protein carbonylation, to track the level of chemical oxidation and photochemical (UV) oxidation of human hair. The second objective is to investigate how the protein carbonylation biomarker evolution is associated with physical characteristics of the fibre. The third objective is to understand the damage localization within the hair sub‐structure.Materials and MethodsFor the chemical oxidation study European natural hair 6/0 (medium brown) is treated with non‐pigmented commercial hair colour mixture and hair bleaching in increasing chemical oxidation conditions. For the photochemical study two European natural hair colours, 4/0 (dark brown) and 9/0 (extra light blond) are gradually photo irradiated. Molecular changes are investigated through cysteic acid measurement by NIR spectroscopy and protein carbonylation measurement; Biophysical changes by differential scanning calorimetry (DSC), and tensile strength measurements. Carbonyls are labelled with a specific fluorescent probe and measured in gel electrophoresis and in situ through image analysis and densitometric quantification after protein extraction respectively.ResultsThe two molecular markers, cysteic acid and protein carbonylation, increase similarly in both chemical and photochemical oxidation cases and show a good level of association across the oxidation levels. The fibre physical characteristics (DSC, Tensile Strength) decrease while the protein carbonylation and cysteic acid increase. The in situ visualization of the protein carbonylation shows a high impact on the hair cuticle and a gradual increase of photo‐oxidation through the cortex, phenomenon which is more prominent for the extra light blonde hair in the case of photochemical oxidation.ConclusionThe protein carbonylation biomarker is validated as another key molecular marker to monitor oxidative chemical changes in the hair chemical groups. It complements the cysteic acid, and appears more suitable in the case of photochemical oxidation, where it offers clear advantages over cysteic acid by being more sensitive and accurate, and by allowing in situ distinct damage visualization. Besides cysteic acid, amino acids such as proline, threonine, arginine, lysine, and peptide bonds are targets of oxidation. Under photochemical oxidation, the photoprotective effect of melanin is confirmed.

BackgroundMatrine, a bioactive isoquinoline alkaloid, exhibits antitumor efficacy by modulating multiple signaling pathways to suppress cancer cell proliferation, migration and invasion. However, its metabolic regulatory mechanisms in prostate cancer intervention require systematic characterization.MethodsWe implemented matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) for spatial metabolomic profiling of prostate tissues, integrated with multivariate analytical approaches including principal component analysis, Pearson correlation-based clustering heatmap, partial least squares-discriminant analysis, and hierarchical clustering heatmap analysis. This multimodal strategy enabled comparative evaluation of low-molecular-weight metabolite distributions across normal control, prostate cancer, and matrine-treated prostate cancer cohorts.ResultsMulti-omics integration identified 19 discriminant metabolites (VIP >1.0) spanning lipid signaling mediators (choline, glycerophosphoglycerol, sphinganine, glycerophosphoinositol, linoleic acid, oleic acid, N,N-Dimethylsphingosine), amino acid network regulators (cysteic acid, 5-Hydroxylysine, glutamine-glutamate axis components), nucleotide biosynthesis (adenine, Ribose 1,5-bisphosphate, uracil, dihydrouracil, deoxyinosine, adenosine), markers of oxidative damage (8-Hydroxyguanine) and cofactor of nitric oxide synthases and aromatic amino acid hydroxylases (tetrahydropteridine). Linoleic acid, oleic acid, and N,N-Dimethylsphingosine exhibited the highest levels in the NC group; these metabolites were significantly downregulated in the PCa group and partially restored in the PCa+MAT group. In addition, the results revealed a progressive depletion of tetrahydropteridine across experimental groups, with the PCa+MAT group exhibiting significantly lower tetrahydropteridine levels compared to both NC and PCa groups (PCa+MAT < NC < PCa). Notably, the expression levels of other compounds were the lowest in the NC group, while they were significantly upregulated in the PCa group and with intermediate levels observed in the PCa+MAT group. Spatial metabolomics delineated dynamic metabolic reprogramming during prostate cancer progression, with matrine treatment demonstrating partial reversal of cancer-associated metabolic shifts, particularly in lipid pathways, underscoring its potential as a modulator of oncogenic metabolism.ConclusionThis study establishes MALDI-MSI as a powerful platform for pharmacometabolomic evaluation, while elucidating matrine’s therapeutic potential through coordinated regulation of lipid metabolic remodeling, amino acid/nucleotide biosynthesis pathways and oxidative stress responses. Our findings provide mechanistic insights into matrine’s anticancer action and validate metabolomic approaches for natural product evaluation.

This study is a continuation of our previous research aimed at investigating changes in the pools of amino acids in the myocardium of the ground squirrel during winter torpor. Neurochemical profiles of amino acids and the secondary metabolites (taurine, phosphoserine, and cysteic acid) were explored in the neocortex of the ground squirrel at different stages of torpor: in the beginning of torpor (2–3 days) and during prolonged torpor (9–10 days), as well as during short-term winter arousal (winter activity, euthermia). Reduced excitatory neurotransmitter levels (glutamate by 7% and 14%; aspartate by 25% and 52% in a coordinated manner and the increased level of GABA, the main transmission inhibitor (by 50% and 67%) were observed from the onset of the torpor entry and at the end of the torpor arousal, respectively. Alanine, which was formed in negligible amounts in the neocortex in the summer season, increased at the initial stage of hibernation and after multiday torpor bout (by 98% and 126%, respectively), indicating a partial switch to anaerobic glycolysis. Short-term inter-bout euthermia returned levels of these substances back to normal. The behavior of glutamate and aspartate, the anaplerotic substrates, that supported cycling of the tricarboxylic acid cycle during torpor and winter activity periods was like their responses in the myocardium, though differed quantitatively. The responses of the neuromodulators such as glycine, threonine, and lysine differed radically when compared to their responses in the myocardium. No changes in taurine and phosphoserine pools were detected, but the level of cysteic acid decreased compared to the summer control from 0.51 ± 0.06 μmol/g to 0.07 ± 0.01 μmol/g at the end of torpor, while during winter euthermia it became 2 times lower than the summer level. Our data suggest that metabolic pathways, involving anaplerotic amino acids of the neocortex, are more active than the myocardium during winter torpor, while the pools of neuromodulators that regulate inhibition processes, increase.

Amid the bourgeoning demand for in-silico designed, environmentally sustainable, and highly effective hair care formulations, a growing interest is evident in the exploration of realistic computational model for the hair surface. In this work, we present an atomistic model for the outermost layer of the hair surface derived through molecular dynamics simulations, which comprises 18-Methyleicosanoic acid (18-MEA) fatty acid chains covalently bound onto the keratin-associated protein 10-4 (KAP10-4) at a spacing distance of ~1 nm. Remarkably, this hair surface model facilitates the inclusion of free fatty acids (free 18-MEA) into the gaps between chemically bound 18-MEA chains, up to a maximum number that results in a packing density of 0.22 nm2 per fatty acid molecule, consistent with the optimal spacing identified through free energy analysis. Atomistic insights are provided for the organization of fatty acid chains, structural features, and interaction energies on protein-inclusive hair surface models with varying amounts of free 18-MEA (FMEA) depletion, as well as varying degrees of anionic cysteic acid from damaged bound 18-MEA (BMEA), under both dry and wet conditions. In the presence of FMEA and water, the fatty acid chains in a pristine hair surface prefers to adopt a thermodynamically favored extended chain conformation, forming a thicker protective layer (~3 nm) on the protein surface. Our simulation results reveal that, while the depletion of FMEA can induce a pronounced impact on the thickness, tilt angle, and order parameters of fatty acid chains, the removal of BMEA has a marked effect on water penetration. There is a "sweet spot" spacing between the 18-MEA whereby damaged hair surface properties can be reinstated by replenishing FMEA. Through the incorporation of the protein layer and free fatty acids, the hair surface models presented in this study enables a realistic representation of the intricate details within the hair epicuticle, facilitating a molecular scale assessment of surface properties during the formulation design process.

The ceramic membrane surfaces coated with cysteic acid were tested for efficacy and the fouling rate at constant crossflow velocities (CFV) and two transmembrane pressures (TMP). The crossflow mode was used during the filtration process to enable the membranes to perform for longer periods. The calculated variability and substance rejection were used to determine the performance of the membranes. In addition, cleaning in situ (CIP) was performed on the membranes to ensure that the flux recovery process was executed smoothly after each run. The current study uses ceramic microfiltration membranes to investigate the effectiveness of a 2600-ppm calcium carbonate solution and 260-ppm 4-nitrophenol extraction/removal from water samples. The concentrations of Ca2+ ions of the distinct concentration samples were reduced by 89–96% by non-coating and coating ceramic microfiltration membranes for a three-hour reaction time. At the end of the run, the concentration of the solution was at a TMP of 0.20 MPa with an efficiency of about 99.5% at t = 160 min with a sustainable flux.

Metabolome analyses of skin dialysate: Insights into skin interstitial fluid biomarkers

Alkali hydrolysis of wool fibres using microwave irradiation as a recycling approach for handling wool-waste

Dietary betaine supplementation has been reported to alleviate the adverse effects of high-carbohydrate diets on Megalobrama amblycephala, while the regulatory mechanism remains largely unknown. In the present study, a 79-day feeding trial was conducted with 450 juvenile Megalobrama amblycephala (average weight 6.75 ± 0.10 g), which were fed with five high-carbohydrate diets (43%) supplementing betaine at 0% (CD group), 0.2% (0.2Bet group), 0.4% (0.4Bet group), 0.8% (0.8Bet group), and 1.6% (1.6Bet group), respectively. Results showed M. amblycephala in 0.8Bet group exhibited the best growth performance, indicated by the largest weight gain ratio (142.88%) and least feed conversion ratio (1.63). Moreover, liver health was promoted in 0.8Bet group, with decreased number of non-nucleated cells and less lipid accumulation, which was accompanied by the lowest hepatosomatic index (1.38%). In order to further illustrate the regulatory mechanism, metabolites assay indicated that dietary betaine supplementation significantly increased plasma contents of methionine, serine, hypotaurine, and taurine, but did not affect plasma contents of cystathionine, cystine, or cysteic acid. Accordingly, the mRNA expressions of cysteine sulfinate decarboxylase in cysteine sulfinic acid pathway and cysteamine dioxygenase (ADO) in sulfinic acid (CS) pathway, which were both involved in taurine synthesis, were also upregulated in the liver. Meanwhile, the microbial communities in M. amblycephala intestine were more stable and uniform with betaine supplementation. Therefore, dietary betaine supplementation may exert its protective roles in improving feed efficiency and liver health of M. amblycephala via promoting de novo taurine synthesis and stabilizing intestinal microbial communities.

In silico study of the impact of oxidation on pyruvate transmission across the hVDAC1 protein channel

Horsehairs present several common characteristics in their chemical composition and molecular structure. The present study aims to analyze the physical characteristics of horsehairs belonging to different breeds. Morphological analysis of the horsehair fibers was performed using Scanning Electron Microscopy (SEM) and molecular structural characterization using the Raman Spectroscopy (RS) technique. Horse hairs were collected from three different horse groups (group A: mixed-breed; group B: Italian saddle; group C: thoroughbred). Each group was constituted of five horses with a mean body weight of 475 ± 25 kg, aged between 12 and 15 years old. SEM images showed differences in the surface layer (cuticula) and diameter size of horsehairs referred to different breeds. The investigation conducted through RS showed differences in the S – O band, located at 1044 cm−1, where cysteic acid is one of the amino acid constituents of α-keratin; in CH2 bending mode and CH stretching, located at ~1450 cm-1 and ~2900 cm-1, respectively. These differences could be attributed to genetic predisposition or metabolism; they could represent the real differentiation among the breeds, detectable by using RS.

To establish a rapid, accurate and safe pretreatment method for the determination of cystine in milk powder. Samples were oxidized at 50 ℃ for 10 min after adding performic acid, and then the reaction was terminated with ethanol as oxidation terminator. The reaction solution was concentrate to dryness by vacuum centrifugation at 50 ℃. The residue was hydrolyzed at 145 ℃ for 4 h after adding 15 mL hydrochloric acid(6 mol/L). Quantitatively transfer the hydrolysate to 25 mL volumetric flask, rinsing with water, and dilute to volume. A proper amount of hydrolysate was concentrated to dryness by vacuum centrifugation at 50 ℃, dissolved in sodium citrate buffer, filtered, and determined by amino acid analyzer. A rapid detection method of cystine in milk powder was realized in this study. Cysteic acid were linearly correlated within the set range, and the correlation coefficients were more than 0.999. This method was applied to the determination of milk powder reference material SRM1849A. The result was within the range of values, and the precision was all less than 4%; The detection limit of cystine was 0.001%, and the limit of quantitation was 0.003%. The applicability of this approach was validated by a comparison study with milk powder reference material(SRM 1869). To explore the scalability of the method, fish meal and soybean meal were measured for six times under the above conditions according to the classification of animals and plants. Meanwhile, milk powder, fish meal and soybean meal were also measured according to GB/T 15399-2018 as reference value. The relative deviation of the average values measured by both method were all less than 6%. This method is simple and rapid, with good repeatability and high accuracy, and less harm to the operators and experimental equipment. It can be used for the rapid detection of cystine in milk powder, and it also has applicability to other complex samples.

Identification and expression analysis of transcripts involved in taurine biosynthesis during early ontogeny of tropical gar Atractosteus tropicus

In this procedure, we describe a high-throughput absolute quantification protocol for the protein-bound sulfur amino acids, cysteine (Cys) and methionine (Met), from plant seeds. This procedure consists of performic acid oxidation that transforms bound Cys into cysteic acid (CysA) and bound Met into methionine sulfone (MetS) followed by acid hydrolysis. The absolute quantification step is performed by multiple reaction monitoring tandem mass spectrometry (LC-MS/MS). The approach facilitates the analysis of a few hundred samples per week by using a 96-well plate extraction setup. Importantly, the method uses only ∼4 mg of tissue per sample and uses the common acid hydrolysis protocol, followed by water extraction that includes DL-Ser-d3 and L-Met-d3 as internal standards to enable the quantification of the absolute levels of the protein-bound Cys and Met with high precision, accuracy, and reproducibility. The protocol described herein has been optimized for seed samples from Arabidopsis thaliana, Glycine max, and Zea mays but could be applied to other plant tissues. © 2023 Wiley Periodicals LLC. Basic Protocol: Analysis of protein-bound cysteine and methionine from seeds.

This work analyses 10 adsorption isotherm models applied to adsorption of Cr(III) and Cu(II) from binary solutions on electron-irradiated sheep wool (0-24-100) kGy. The results are compared with fitting the same adsorbates from corresponding single solutions. The competing cation significantly changes the fitting of the selected isotherms to the extent that even simultaneous fitting of the same cation in the single and binary solution is rare. In the case of Cr(III), 4 favourable matches were found out of 30 compared cases, while in the case of Cu(II), only 2 conformities were found. Having the Cr(III) coordination number exclusively of 6, but Cu(II) up to 4, 5, 6, the last coordinates more easily with the ligands provided by keratin, resulting in preferential chemisorption. If there is still a lack of cysteic acid in the wool to interact with Cr(III) also, this is adsorbed on the wool physically, too. The amount of cysteic acid increasing in the wool with the absorbed dose of energy improves the chemisorption of Cr(III), as well. It can be summarized that during competitive adsorption, Cu(II) binds by chemisorption and Cr(III) by both physisorption and chemisorption, depending on the dose of energy absorbed by the wool.

Цель. Изучить особенности метаболома у беременных с задержкой роста плода.Материалы и методы. В ходе исследования изучены образцы плазмы крови 41 женщины. Беременные были разделены на группы: 1-ю группу составила 21 беременная с задержкой роста плода, 2-ю группу – 20 женщин с физиологическим течением беременности. Анализ образцов был осуществлен с помощью высокоэффективной жидкостной хроматографии. Статистическая обработка полученных данных осуществлялась с использованием пакета программ Statistica 10.0 (SN – AXAR207F394425FA-Q).Результаты. У пациенток с задержкой роста плода в плазме крови выявлено статистически значимое повышение 14 аминокислот и их производных по сравнению с контрольной группой: цистеиновой кислоты (СА), фосфосерина (PSer), аспарагина (Asn), серина (Ser), треонина (Thr), 1-метилгистидина (1MHis), 3-метилгистидина (1MHis), аргинина (Arg), симметричного диметиларгинина (SDMA), α-аминомасляной кислоты (αАВА), β-аминомасляной кислоты (βАВА), метионина (Met), триптофана (Trp), лейцина (Leu). Выявлена умеренная корреляционная связь массы плода с уровнем цистеиновой кислоты (СА), фосфосерина (PSer), серина (Ser), 3-метилгистидина (3MHis), треонина (Thr), аланина (Ala), таурина (Tau), симметричного диметиларгинина (SDMA), α-аминомасляной кислоты (aABA), β-аминомасляной кислоты (βАВА), триптофана (Trp); сильная корреляционная связь определена с аспарагином (Asn).Заключение. Полученные результаты обосновывают перспективность изучения метаболомики в качестве диагностических маркеров задержки роста плода. Purpose. To study the features of the metabolome in pregnant women with fetal growth retardation.Materials and methods. During the study, blood plasma samples from 41 women were studied. The pregnant women were divided into groups: the 1st group consisted of 21 pregnant women with fetal growth retardation, the 2nd group – 20 women with a physiological course of pregnancy. Samples were analyzed by high performance liquid chromatography. Statistical processing of the obtained data was carried out using the Statistica 10.0 software package (SN – AXAR207F394425FA-Q).Results. In patients with fetal growth retardation in blood plasma, a statistically significant increase in 14 amino acids and their derivatives was revealed compared to the control group: cysteic acid (CA), phosphoserine (PSer), asparagine (Asn), serine (Ser), threonine (Thr), 1-methylhistidine (1MHis), 3-methylhistidine (1MHis), arginine (Arg), symmetrical dimethylarginine (SDMA), α-aminobutyric acid (αABA), β-aminobutyric acid (βABA), methionine (Met), tryptophan (Trp), leucine (Leu). A moderate correlation was found between fetal weight and the level of cysteic acid (CA), phosphoserine (PSer), serine (Ser), 3-methylhistidine (3MHis), threonine (Thr), alanine (Ala), taurine (Tau), symmetrical dimethylarginine (SDMA), α-aminobutyric acid (aABA), β-aminobutyric acid (βABA), tryptophan (Trp); a strong correlation was determined with asparagine (Asn).Conclusion. The results obtained substantiate the prospects of studying metabolomics as diagnostic markers of fetal growth retardation.