FeNi-MIL-88B-based electrochemiluminescence immunosensor for ultra-sensitive detection of CD44 protein via dual-quenching strategy.

BACKGROUND: Cluster of Differentiation 44 (CD44) is considered an important biomarker for various cancers, and achieving highly sensitive detection of CD44 is crucial, which plays a significant role in tumor invasion and metastasis, providing essential information for clinical tumor diagnosis. Commonly used methods for analysis include fluorescence spectroscopy (FL), photoelectrochemical analysis (PEC), electrochemical analysis (EC), and commercial ELISA kits. Although these methods offer high sensitivity, they can be relatively complex to perform experimentally. Electrochemiluminescence (ECL) has gained widespread research attention due to its high sensitivity, ease of operation, effective spatiotemporal control, and close to zero background signal. RESULTS: In this work, a sandwich-type ECL immunosensor for detecting CD44 was constructed using luminol as a luminophore. In this sensing platform, bimetallic MOFs (Pd@FeNi-MIL-88B) loaded with palladium nanoparticles (Pd NPs) were used as a novel enzyme mimic, exhibiting excellent catalytic performance towards the electroreduction of H2O2. The hybrids provided a strong support platform for luminol and antibodies, significantly enhancing the initial ECL signal of luminol. Subsequently, core-shell Au@MnO2 nanocomposites were synthesised by gold nanoparticles (Au NPs) encapsulated in manganese dioxide (MnO2) thin layers, as labels. In the luminol/H2O2 system, Au@MnO2 exhibited strong light absorption in the broad UV-vis spectrum, similar to the black body effect, and the scavenging effect of Mn2+ on O2•-, which achieved the dual-quenching of ECL signal. Under the optimal experimental conditions, the immunosensor demonstrated a detection range of 0.1 pg mL-1 - 100 ng mL-1, with a detection limit of 0.069 pg mL-1. SIGNIFICANCE: Based on Pd@FeNi-MIL-88B nanoenzymes and Au@MnO2 nanocomposites, a dual-quenching sandwich-type ECL immunosensor for the detection of CD44 was constructed. The proposed immunosensor exhibited excellent reproducibility, stability, selectivity, and sensitivity, and provided a valuable analytical strategy and technical platform for the accurate detection of disease biomarkers, and opened up potential application prospects for early clinical treatment.

Isolation, purification, and physicochemical characterization of Polygonatum polysaccharide and its protective effect against CCl4-induced liver injury via Nrf2 and NF-κB signaling pathways.

This study aimed to provide scientific evidence that Polygonatum polysaccharide can be developed as a dietary supplement and medication for treating liver injuries. A water-soluble polysaccharide (PSP-N-c-1), with an average molecular weight of 3.45 kDa, was isolated and purified from the water extract of Polygonatum using DEAE cellulose column chromatography, CL-6B agarose gel chromatography, and Sephadex G100 chromatography. High-performance liquid chromatography, gas chromatography-mass spectrometry, and nuclear magnetic resonance spectroscopy analyses revealed that PSP-N-c-1 might be linear α-(1 â†’ 4)-glucans with α-Glcp residues linked to the backbone at C-6. In vitro experiments revealed that PSP-N-c-1 exhibited protective effects against CCl4-induced damage in HepG2 cells. In vivo experiments demonstrated that PSP-N-c-1 exhibited a hepatoprotective effect by enhancing antioxidant enzyme activity, inhibiting lipid peroxidation, and reducing the activity of pro-inflammatory mediators. Besides, PSP-N-c-1 could attenuate oxidative stress and inflammatory responses by activating the Nrf2-mediated signaling pathways and regulating the TLR4-mediated NF-κB signaling pathways. These findings demonstrated that PSP-N-c-1 may serve as a supplement for alleviating chemical liver damage.

Preparation of Microcrystalline Cellulose/N-(2-aminoethyl)-3- Aminopropyl Methyl Dimethoxysilane Composite Aerogel and Adsorption Properties for Formaldehyde.

Air pollution is related to the development of the national economy and people's livelihoods. Formaldehyde, as one of the main pollutants in the air, affects people's physical and mental health. In order to remove formaldehyde and better protect the health of residents, it is necessary to develop efficient adsorption materials. In this study, APMDS-modified cellulose composite aerogel microcrystalline was investigated. The adsorption of formaldehyde by the MCC/APMDS (Microcrystalline Cellulose/N-(2-aminoethyl)-3- Aminopropyl Methyl Dimethoxysilane) composite aerogel mainly relied upon the reaction of the protonated -NH3+ group in APMDS with formaldehyde to form a Schiff base to achieve the effect of deformaldehyde. Meanwhile, the modification of the aerogel reduced the pore volume and specific surface area, and the average pore size increased to 14.56 nm, which enhanced the adsorption capacity of formaldehyde, and the adsorption amount reached 9.52 mg/g. This study provides valuable information for the preparation of adsorbent materials with high formaldehyde adsorption capacity for air purification.

Structural characterization and antagonistic effect against P-selectin-mediated function of SFF-32, a fucoidan fraction from Sargassum fusiforme.

ETHNOPHARMACOLOGICAL RELEVANCE: Sargassum fusiforme (Harvey) Setchell, or Haizao, has been used in traditional Chinese medicine (TCM) since at least the eighth century a.d. S. fusiforme is an essential component of several Chinese formulas, including Haizao Yuhu Decoction, used to treat goiter, and Neixiao Lei Li Wan used to treat scrofuloderma. The pharmacological efficacy of S. fusiforme may be related to its anti-inflammatory effect. AIM OF THE STUDY: To determine the structural characteristics of SFF-32, a fucoidan fraction from S. fusiforme, and its antagonistic effect against P-selectin mediated function. MATERIALS AND METHODS: The primary structure of SFF-32 was determined using methylation/GC-MS and NMR analysis. Surface morphology and solution conformation of SFF-32 were determined by scanning electron microscopy (SEM), Congo red test, and circular dichroic (CD) chromatography, respectively. The inhibitory effects of SFF-32 against the binding of P-selectin to HL-60 cells were evaluated using flow cytometry, static adhesion assay, and parallel-plate flow chamber assay. Furthermore, the blocking effect of SFF-32 on the interaction between P-selectin and PSGL-1 was evaluated using an in vitro protein binding assay. RESULTS: The main linkage types of SFF-32 were proven to →[3)-α-l-Fucp-(1→3,4)-α-l-Fucp-(1]2→[4)-ß-d-Manp-(1→3)-d-GlcAp-(1]2→4)-ß-d-Manp-(1→3)-ß-d-Glcp-(1→4)-ß-d-Manp-(1→2,3)-ß-d-Galp-(1→4)-ß-d-Manp-(1→[4)-α-l-Rhap-(1]3→. The sulfated unit or terminal xylose residues were attached to the backbone through the C-3 of some fucose residues and terminal xylose residues were attached to C-3 of galactose residues. Moreover, SFF-32 disrupted P-selectin-mediated cell adhesion and rolling as well as blocked the interaction between P-selectin and its physiological ligand PSGL-1 in a dose-dependent manner. CONCLUSIONS: Blocking the binding between P-selectin and PSGL-1 is the possible underlying mechanism by which SFF-32 inhibits P-selectin-mediated function, which demonstrated that SFF-32 may be a potential anti-inflammatory lead compound.

Bis(ethylmaltolato)oxidovanadium (IV) alleviates neuronal apoptosis through regulating peroxisome proliferator-activated receptor γ in a triple transgenic animal model of Alzheimer's disease.

Endoplasmic reticulum stress (ER stress) plays a critical role in neuronal apoptosis along with the aggravation of Alzheimer's disease (AD). Nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ) is a ligand-activated transcription factor that is involved in regulating ER stress in Alzheimer's disease (AD), therefore, this protein could be a promising therapeutic target for AD. Vanadium compounds, such as vanadyl acetylacetonate, sodium metavanadate and bis(maltolato)oxovanadium, are well-known as puissant PPARγ modulators. Thus, we are curious whether bis(ethylmaltolato)oxidovanadium (IV) (BEOV) can ameliorate ER stress and subsequent neuronal apoptosis by regulating PPARγ in AD models. To this end, we determined the effect of BEOV on behavioral performance, ER stress and neuronal apoptosis in the triple transgenic mouse AD model (3×Tg-AD). Our results showed that BEOV improved cognitive abilities and reduced the ER stress- and apoptosis-associated proteins in the brains of 3×Tg-AD mice. In vitro administration of BEOV in primary hippocampal neurons and N2asw cells achieved similar results in repressing ER stress. In addition, cotreatment with GW9662 (an antagonist of PPARγ) effectively blocked these neuroprotective effects of BEOV, which provided strong evidence that PPARγ-dependent signaling plays a key role in protecting against ER stress and neuronal apoptosis in AD. In conclusion, our data demonstrated that BEOV alleviated neuronal apoptosis triggered by ER stress by regulating PPARγ in a 3×Tg-AD model.

The Function of Selenium in Central Nervous System: Lessons from MsrB1 Knockout Mouse Models.

MsrB1 used to be named selenoprotein R, for it was first identified as a selenocysteine containing protein by searching for the selenocysteine insert sequence (SECIS) in the human genome. Later, it was found that MsrB1 is homologous to PilB in Neisseria gonorrhoeae, which is a methionine sulfoxide reductase (Msr), specifically reducing L-methionine sulfoxide (L-Met-O) in proteins. In humans and mice, four members constitute the Msr family, which are MsrA, MsrB1, MsrB2, and MsrB3. MsrA can reduce free or protein-containing L-Met-O (S), whereas MsrBs can only function on the L-Met-O (R) epimer in proteins. Though there are isomerases existent that could transfer L-Met-O (S) to L-Met-O (R) and vice-versa, the loss of Msr individually results in different phenotypes in mice models. These observations indicate that the function of one Msr cannot be totally complemented by another. Among the mammalian Msrs, MsrB1 is the only selenocysteine-containing protein, and we recently found that loss of MsrB1 perturbs the synaptic plasticity in mice, along with the astrogliosis in their brains. In this review, we summarized the effects resulting from Msr deficiency and the bioactivity of selenium in the central nervous system, especially those that we learned from the MsrB1 knockout mouse model. We hope it will be helpful in better understanding how the trace element selenium participates in the reduction of L-Met-O and becomes involved in neurobiology.

Structural characterization and α-glycosidase inhibitory activity of a novel polysaccharide fraction from Aconitum coreanum.

α-Glycosidase is an essential target for the management of postprandial serum glucose in diabetic patients. Therefore, the interest has been growing in the screening of α-glycosidase inhibitor from natural resource. In the present study, the structure and α-glycosidase inhibitory activity of a polysaccharide (named as ACPP-1) from Aconitum coreanum were investigated. Based on the results from high performance gel permeation chromatography, GC-MS and 1D/2D nuclear magnetic resonance spectroscopy, ACPP-1 was a highly-linear polysaccharide with a molecular weight of 34.0 kD and containing over 90 % of glucose. It was composed of (1→4)-α-d-Glcp and α-Araf. ACPP-1 exhibited a dose-dependent inhibitory eff ;ect against α-glycosidase activity in vitro and the IC50 value was ∼0.8 mg/mL. In oral starch tolerance test, treatment with ACPP-1 (800 mg/kg) significantly improved the starch tolerance in mice. Taken together, this study provided a potential intervention and management for postprandial hyperglycemia by the polysaccharide fraction from A. coreanum.

Loss of MsrB1 perturbs spatial learning and long-term potentiation/long-term depression in mice.

MsrB1 belongs to the methionine sulfoxide reductase family, it is also known as selenoprotein R for the sake of possessing a selenocysteine residue. It has been reported that MsrB1 could interact with actin, TRPM6, clusterin, and amyloid-beta in vitro. Thus, we presumed that MsrB1 may play an important role in central nervous system. To examine whether MsrB1 knockout has any effects on brain development or learning behavior, we carried out histological study on brains of MsrB1 deficient mice, and further tested spatial learning ability and long-term synaptic plasticity of these mice by using Morris water maze and electrophysiological methods. It was observed that loss of MsrB1 did not perturb the overall development of central nervous system except for the astrogliosis in hippocampus, however, it led mice to be incapable in spatial learning and severe impairments in LTP/LTD expression in CA1 of brain slices, along with the down-regulation of the synaptic proteins including PSD95, SYP, GluN2A and GluN2B, as well as the dramatic decrease of CaMKIIs phosphorylation at 286(287) compared with wild type mice. Taken together, these results suggest that MsrB1 is essential for mice spatial learning and LTP/LTD induction, and the MsrB1 related redox homeostasis may be involved in regulating the phosphorylation of CaMKIIs.

Sulfated polysaccharides from Rhodiola sachalinensis reduce d-gal-induced oxidative stress in NIH 3T3 cells.

In this study, three sulfated polysaccharides (S-RSP1-2, S-RSP1-4 and S-RSP1-8) from Rhodiola sachalinensis were produced by chlorosulfonic acid-pyridine method. d-gal was used to develop an oxidative stress model in the mouse embryonic fibroblast cell line NIH 3T3. Effects of the three sulfated polysaccharides on d-gal-induced oxidative stress were investigated. The results showed that S-RSP1-4 improved the viability of the d-gal-induced oxidative stress in NIH 3T3 cells. The sulfated polysaccharides were found to have a better protective effect against d-gal-induced oxidative stress as compared to the native polysaccharide. Scanning electronmicroscopy also showed a significant change in the surface morphology of sulfated polysaccharides. In addition, the sulfated polysaccharides had noticeable DPPH radical-scavenging activity. In summary, our results demonstrated that d-gal was able to induce oxidative stress in NIH 3T3 cells, and sulfated group might play an important role in resistance to d-gal-induced oxidative damage.

Physicochemical characterization of Sargassum fusiforme fucoidan fractions and their antagonistic effect against P-selectin-mediated cell adhesion.

P-selectin, mediated adhesion between endothelium and neutrophils, is a promising target for the therapeutics of acute inflammatory-related diseases. It is reported that brown algal fucoidans can antagonize P-selectin function. However, the fractionation and physicochemical characterization of Sargassum fusiforme fucoidan, and the screening of fucoidan fractions with P-selectin antagonistic capability have not been investigated. In this study, we isolated and fractionated systematically the S. fusiforme fucoidan by ion-exchange chromatography and size exclusion chromatography to obtain eight fucoidan fractions. Their physicochemical characterization was determined by chemical methods, HPLC and FT-IR. The inhibitory capacity of the fucoidan fractions in P-selectin-mediated leukocyte adhesion was evaluated by static adhesion assay and parallel-plate flow chamber. Results showed that fucoidan fractions possessed distinct physicochemical properties, including total carbohydrate, uronic acid and sulfate contents, molecular weight, and monosaccharide compositions. Among all the fucoidan fractions, SFF-32 and SFF-42 showed better blocking ability against P-selectin-mediated cell adhesion.

Radical scavenging activity of sulfated Bupleurum chinense polysaccharides and their effects against oxidative stress-induced senescence.

In this study, BCPS-1, a polysaccharide previously isolated and characterized from Bupleurum chinense was chemically modified to yield two sulfated derivatives, which we designated as S-BCP1-4 and S-BCP1-8. The physicochemical properties of these sulfated derivatives were then determined by high performance liquid chromatography (HPLC), Fourier transform infrared spectrometry (FT-IR), and gas chromatography (GC), and then compared with those of BCPS-1. Furthermore, the antioxidant activities of all three polysaccharides were also evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical assay, superoxide radical assay and hydroxyl radical assay, while their effects against H2O2-induced cellular senescence were determined using senescence-associated ß-galactosidase (SA-ß-gal) staining, cell cycle assay and immunoblotting in H2O2-induced mouse lung endothelial cells (MLECs). Compared to BCPS-1, S-BCP1-4 and S-BCP1-8 exhibited remarkable antioxidant effect, and in a concentration-dependent manner. They also provided stronger protection against H2O2-induced cellular senescence in MLECs. These results indicated that the sulfate group in the modified B. chinense polysaccharides might play an important role in radical scavenging and resistance to H2O2-induced senescence. These sulfated polysaccharides could be considered as novel pharmaceutical products with potential antioxidant and anti-senescence effects.

Engineered Hsp Protein Nanocages for siRNA Delivery.

The efficient delivery of small interfering RNA (siRNA) to tumor cells still remains a great challenge. Of the various nanocarriers, protein nanocages have attracted extensive interest due to their unique structure and suitable characteristics derived from their proteinaceous nature. However, most reported protein nanocages that are developed are based on virus capsid proteins, which may raise safety concerns, including those related to gene mutation and carcinogenesis. The development of nonviral protein-based systems for siRNA delivery is greatly needed. In this study, a novel siRNA delivery system based on heat shock protein (Hsp) nanocages is developed by a genetic engineering method. The delivery system could condense siRNA into stable complexes and protect the condensed siRNA from degradation. A cellular uptake analysis shows that siRNA is introduced into tumor cells mediated by Hsp-R9 nanocages. Green fluorescent protein (GFP) expression in HeLa-EGFP cells is significantly downregulated by Hsp-R9/siRNA complexes. The results indicate that Hsp nanocages may be a good platform for siRNA delivery into tumor cells.

Inhibitory function of P-selectin-mediated leukocyte adhesion by the polysaccharides from Sanguisorba officinalis.

CONTEXT: P-selectin is a promising target for inflammatory-related diseases. Polysaccharides are the active ingredients of Sanguisorba officinalis L. (Rosaceae) responsible for its anti-inflammatory activities; however, the molecular mechanism is not clear yet. OBJECTIVE: This study evaluates the effects of polysaccharides (SOPs) from Sanguisorba officinalis on their antagonistic function against P-selectin-mediated leukocyte adhesion. MATERIALS AND METHODS: The antagonistic function of SOPs was investigated by flow cytometry and static adhesion assay at the concentrations of 25 and 100 µg/ml. The dynamic interaction between HL-60 cells and CHO-P cell monolayer treated with SOPs (25 and 100 µg/ml) was analyzed in a parallel plate flow chamber, and quantitatively calculated by ImageJ software (NIH, Bethesda, MD). In vitro protein binding assay was carried out to evaluate the blocking effects of SOPs (25 and 100 µg/ml) on the interaction between P-selectin and PSGL-1. RESULTS: SOPs-treatment (100 µg/ml) significantly reduced the percentage of HL-60 cells binding to P-selectin (p < 0.01) determined by flow cytometry. In addition, SOPs (25 and 100 µg/ml) markedly blocked the adhesion between HL-60 cells and CHO-P cells under static condition, and the inhibitory rates reached 39.9% and 71.2%, respectively. Compared with the positive control group, SOPs-treatment (25 and 100 µg/ml) significantly reduced the percentage of HL-60 cells rolling on CHO-P cell monolayers by 43.5% and 75.2%, respectively. Protein binding assay showed the interaction between P-selectin and PSGL-1 was significantly blocked by SOPs. DISCUSSION AND CONCLUSION: SOPs possess a significant antagonistic function against P-selectin-mediated leukocyte adhesion, and SOPs could be considered as a promising candidate for amelioration of inflammation-related diseases.

A simple structural hydrazide-based gelator as a fluoride ion colorimetric sensor.

A 4-nitrobenzohydrazide derivative, N-(3,4,5-octyloxybenzoyl)-N'-(4'-nitrobenzoyl)hydrazine (C8), was synthesized. It could form stable gels in some of the tested organic solvents. The wide-angle X-ray diffraction analysis showed that the xerogels exhibited a layered structure. SEM images revealed that the molecules self-assembled into fibrous aggregates in the xerogels. FT-IR studies confirmed that the intermolecular hydrogen bonding between C=O and N-H groups was the major driving force for the formation of self-assembling gel processes. The gel is utilized for a 'naked eye' detection of fluoride ions, through a reversible gel-sol transition, which is associated with a color change from colorless to red. An extended conjugated system formed through the phenyl group and a five-membered ring based on intramolecular hydrogen bonding between the oxygen atom near the deprotonation nitrogen atom and the other NH, which is responsible for the dramatic color change upon addition of fluoride ions.