Previously, we reported the metabolic responses of Pseudomonas sp. strain HF-1, a nicotine-degrading bacterium, to nicotine stress. However, the metabolic effects of nicotine on non-nicotine-degrading bacteria that dominate the environment are still unclear. Here, we have used nuclear magnetic resonance based metabolomics in combination with multivariate data analysis methods to comprehensively analyze the metabolic changes in nicotine-treated Escherichia coli. Our results showed that nicotine caused the changes of energy-related metabolism that we believe are due to enhanced glycolysis and mixed acid fermentation as well as inhibited tricarboxylic acid cycle activity. Furthermore, nicotine resulted in the alteration of choline metabolism with a decreased synthesis of betaine but an increased production of dimethylamine. Moreover, nicotine caused a decrease in amino acid concentration and an alteration of nucleotide synthesis. We hypothesize that these changes caused the decrease in bacterial cell density observed in the experiment. These findings provide a comprehensive insight into the metabolic response of E. coli to nicotine stress. Our study highlights the value of metabolomics in elucidating the metabolic mechanisms of nicotine action.
The cancer/testis antigen HCA587 (also known as MAGE-C2), one of the most immunogenic tumor antigens, is overexpressed in a wide spectrum of malignant tumors and can serve as a target for immunotherapy. In this study, we synthesized 14 overlapping (25-35 amino acids) long peptides representing the sequence of the most immunogenic part of the HCA587 protein and evaluated the antigen-specific immune responses and antitumor effects generated by immunization with the synthetic long peptide (SLP) vaccine in a mouse model. HCA587 SLPs in combination with adjuvants CFA and CpG ODN induced potent T-cell responses, which were dominated by type 1 cytokine IFN-?-producing CD4(+) T cells as measured by ELISPOT and intracellular cytokine staining assay. Moreover, HCA587 SLP vaccination conferred protection against challenge with HCA587-expressing B16 melanoma in a therapeutic setting. Our findings may provide a scientific basis for the use of HCA587-derived long overlapping peptide vaccine for the treatment of patients with cancer in future clinical trials.
Plant metabolomics is essentially the comprehensive analysis of complex metabolites of plant extracts. Metabolic fingerprinting is an important part of plant metabolomics research. In this study, metabolic fingerprinting of different stages of the life history of the red alga Porphyra haitanensis was performed. The stages included conchocelis filaments, sporangial branchlets, conchosporangia, discharged conchospores and conchosporangial branchlets after conchospore discharge. Metabolite extracts were analysed with ultra-performance liquid chromatography coupled with electrospray ionisation quadrupole-time of flight mass spectrometry. Analyses profiles were subjected to principal components analysis and orthogonal projection to latent structures discriminant analysis using the SIMCA-P software for biomarker selection and identification. Based on the MS/MS spectra and data from the literature, potential biomarkers, mainly of phosphatidylcholine and lysophosphatidylcholine, were identified. Identification of these biomarkers suggested that plasma membrane phospholipids underwent major changes during the life history of P. haitanensis. The levels of phosphatidylcholine and lysophosphatidylcholine increased in sporangial branchlets and decreased in discharged conchospores. Moreover, levels of sphingaine (d18:0) decreased in sporangial branchlets and increased in discharged conchospores, which indicates that membrane lipids were increasingly synthesised as energy storage in sporangial branchlets, while energy was consumed in sporangial branchlets to discharged conchospores. A metabolomic study of different growth phases of P. haitanensis will enhance our understanding of its physiology and ecology. This article is protected by copyright. All rights reserved.
Recently, bipolar fuzzy sets have been studied and applied a bit enthusiastically and a bit increasingly. In this paper we prove that bipolar fuzzy sets and [0,1](2)-sets (which have been deeply studied) are actually cryptomorphic mathematical notions. Since researches or modelings on real world problems often involve multi-agent, multi-attribute, multi-object, multi-index, multi-polar information, uncertainty, or/and limit process, we put forward (or highlight) the notion of m-polar fuzzy set (actually, [0,1] (m)-set which can be seen as a generalization of bipolar fuzzy set, where m is an arbitrary ordinal number) and illustrate how many concepts have been defined based on bipolar fuzzy sets and many results which are related to these concepts can be generalized to the case of m-polar fuzzy sets. We also give examples to show how to apply m-polar fuzzy sets in real world problems.
Anti-lactoferrin antibodies (ALA) and anti-myeloperoxidase antibodies (AMPA) are specific serological markers for autoimmune hepatitis (AIH). The project aimed to detect ALA and AMPA and explore their clinical significances in AIH patients. 59 AIH patients, 217 non AIH patients, and 50 healthy controls were enrolled in this study. ALA and AMPA were detected by ELISA. Antineutropil cytoplasmic antibodies (ANCA) and anti-smooth muscle antibodies (ASMA) were examined by indirect immunofluorescence. Antimitochondrial antibody M2 subtype (AMA-M2), anti-liver kidney microsomal antibody Type 1 (LKM1), anti-liver cytosol antibody Type 1 (LC1), and anti-soluble liver antigen/liver-pancreas antibodies (SLA/LP) were tested by immunoblot. The positivity for ALA was 18.6% in AIH group, only one patient in non-AIH group was positive for ALA; the positivity for AMPA was 59.3% in AIH group, with significant differences (P < 0.01) compared with other groups. The specificities for ALA and AMPA were 99.63% and 97.75%; the sensitivities were 18.64% and 59.32%; and the accuracy rates were 84.97% and 90.80%, respectively. A certain correlation was observed between ALA and SLA/LP, AMPA and ANCA, ASMA in AIH group. ALA and AMPA were associated with AIH, and had high clinical diagnostic value. Co-detection with other relative autoantibodies could play an important role in differential diagnosis of AIH.
Poor thermal stability has remained a severe obstacle for practical applications of optical fiber amplifiers based on quantum dots (QDs). We demonstrate that thermal stability at elevated temperatures can be achieved by using oleic-acid-capped QDs. Optical fiber amplifiers using oleic-acid-capped QDs for the gain medium exhibited stable gain of more than 5 dB at 1550 nm between 25 °C and 50 °C that did not degrade upon cooling. In contrast, fiber amplifiers employing oleylamine-capped QDs exhibited reduced gain when heated and subsequently cooled.
The precise identification of fatty acids at the sn-2 position of triacylglycerols (TAGs), especially for positional regioisomers (AAB/ABA), needs to be established during mass spectrometry analysis. The detailed structural information about TAGs is significant not only for the assessment of biofuel quality, but also for the tracing of biosynthetic precursors.
Glycosphingolipids (GSLs) are important components of the cell membrane; however, little is known about GSLs in microalgae. We analyzed GSLs in three strains of Skeletonema microalgae by liquid chromatography coupled with mass spectrometry.
Liposome-microbubble complexes (LMC) have become a promising therapeutic carrier for ultrasound-triggered drug delivery to treat malignant tumors. However, the efficacy for ultrasound-assisted chemotherapy in vivo and the underlying mechanisms remain to be elucidated. Here, we investigated the feasibility of using paclitaxel-liposome-microbubble complexes (PLMC) as possible ultrasound (US)-triggered targeted chemotherapy against breast cancer. PTX-liposomes (PL) were conjugated to the microbubble (MB) surface through biotin-avidin linkage, increasing the drug-loading efficiency of MBs. The significant increased release of payloads from liposome-microbubble complexes was achieved upon US exposure. We used fluorescent quantum dots (QDs) as a model drug to show that released QDs were taken up by 4T1 breast cancer cells treated with QD-liposome-microbubble complexes (QLMC) and US, and uptake depended on the exposure time and intensity of insonication. We found that PLMC plus US inhibited tumor growth more effectively than PL plus US or PLMC without US, not only in vitro, but also in vivo. Histologically, the inhibition of tumor growth appeared to result from increased apoptosis and reduced angiogenesis in tumor xenografts. In addition, a significant increase of drug concentration in tumors was observed in comparison to treatment with non-conjugated PL or PLMC without US. The significant increase in an antitumor efficacy of PLMC plus US suggests their potential use as a new targeted US chemotherapeutic approach to inhibit breast cancer growth.
The cancer testis antigen HCA587 is an attractive candidate for T cell-based immunotherapy because it is overexpressed in a wide spectrum of malignant tumors but not normal tissues, except testis. Several CTL epitopes derived from HCA587 have been described. Our aim was to identify helper T lymphocyte epitopes of HCA587 for the optimization of T cell-based immunotherapies against HCA587-expressing tumors. Candidate helper T lymphocyte epitopes for HCA587 were predicted using the SYFPEITHI algorithm and were tested for their ability to induce helper T lymphocyte responses by in vitro peptide vaccination of CD4(+) T lymphocytes from healthy individuals and hepatocellular carcinoma patients. Four CD4(+) T-cell epitopes for HCA587 (p43-57, p145-159, p186-200 and p249-263) were identified. Among them, the p43-57 epitope was shown to be naturally processed and presented by HCA587-expressing tumor cells as well as autologous dendritic cells pulsed with whole-protein HCA587. Notably, this epitope behaved as a promiscuous T-cell epitope as it stimulated T cells in the context of more than one HLA class II allele. Thus, p43-57 is the first HCA587-derived major histocompatibility complex class II-restricted epitope to fulfil all prerequisites for use as a peptide vaccine in patients with HCA587-expressing tumors.
This study examined the impacts of intrauterine murine cytomegalovirus (MCMV) infection on the long-term learning and memory of offspring. Sexually matured male and female BALB/C mice without MCMV infection were identified by ELISA and then mated. Seventy pregnant mice were randomly divided into the virus group (n=40) and the control group (n=30), in which the pregnant mice were subjected to placenta inoculation of MCMV suspension (1 ?L, 1×106 PFU) or the same amount of cell culture medium, respectively, at gestational age of 12.5 days. Some pregnant mice [virus group (n=20), control group (n=15)] were sacrificed by cervical dislocation at gestational age of 18.5 days, and the head circumference and brain weight of the mouse fetuses were measured, and the MCMV infection in their brain tissues was detected by PCR. The other pregnant mice [virus group (n=20), control group (n=15)] delivered naturally, and the learning and memory capability of the offspring at 70-day-old was analyzed by Morris water maze test. The results showed that 28.57% mouse fetuses in the virus group developed viral infection in the brain. Their head circumference and brain weight were significantly reduced as compared with those in the control group (P<0.01). The Morris water maze test revealed that the mouse offspring in the control group found the platform with straight-line trajectories after training. In contrast, the counterparts in the virus group intended to enter the central area, but looked for the platform with a circular trajectory. And the infected mice exhibited prolonged swimming distance and swimming latency (P<0.01). It was concluded that: (1) placenta inoculation of MCMV can cause fetal brain infection and intrauterine development retardation; (2) the offspring of MCMV placenta inoculation mice showed a long-term decline in learning and memory capability.
The effect of human cytomegalovirus (HCMV) on invasive capability of early pregnant extravillous cytotrophoblasts (EVTs) was investigated in vitro. Primary EVTs were obtained by complex phosphoesterasum digestion and gradient centrifugation from villous tissue aseptically taken from healthy pregnant women. Cytokeratin7 (CK7), vimentin (Vim) and c-erbB-2 were immunocytochemically detected to identify source of cells, and HCMVpp65 antigen was assayed to determine the infection state of primary EVTs by immunocytochemical staining. The EVTs were divided into two groups: control group and HCMV group, and the expression of c-erbB-2, matrix metalloproteinase-2 (MMP-2) and MMP-9 proteins was detected in two groups by immunocytochemistry and Western blotting. Enzymic activity changes of MMP-2 and MMP-9 were tested by gelatin zymography in primary EVTs infected with HCMV. The invasion of primary EVTs was detected by cell invasion assay in vitro after they were infected by HCMV. The cell source identification showed that the cells obtained were highly-pure primary EVTs, and primary EVTs could be infected by HCMV. Primary EVTs could express c-erbB-2, MMP-2 and MMP-9 proteins, and as compared with control group, the protein expression was decreased significantly in HCMV groups (P<0.05). Primary EVTs could secrete active MMP-2 and MMP-9 in vitro, and the activity of two MMPs was decreased significantly in HCMV groups (P<0.05). The in vitro cell invasion assay showed that the number of primary EVTs permeating Matrigel in HCMV group was decreased (P<0.05). We are led to conclude that HCMV can infect primary EVTs and inhibit their invasion capability, suggesting that the impaired EVTs invasion capability might be related to the abnormal expression of c-erbB-2, MMP-2 and MMP-9 proteins.
Congenital cytomegalovirus (CMV) infection is the leading cause of sensorineural hearing loss (SNHL), and SNHL is the most frequent sequela of congenital CMV infection. But the pathogenic mechanism remains unknown, and there is no ideal CMV intrauterine infection animal model to study the mechanisms by which SNHL develops.
Human cytomegalovirus (HCMV) is the most common pathogen in uterus during pregnancy, which may lead to some serious results such as miscarriage, stillbirth, cerebellar malformation, fetus developmental retardation, but its pathogenesis has not been fully explained. The hypofunction of extravillous cytotrophoblast (EVT) invasion is the essential pathologic base of some complications of pregnancy. c-erbB-2 is a kind of oncogene protein and closely linked with embryogenesis, tissue repair and regeneration. Matrix metalloproteinase (MMP) is one of the key enzymes which affect EVT migration and invasion function. The expression level changes of c-erbB-2, MMP-2 and MMP-9 can reflect the changes of EVT invasion function.
The present study examined von Willebrand factor (vWF) levels and ADAMTS13 activity in pregnant and severe preeclamptic women in order to shed light on the prothrombotic state in severe preeclampsia. Thirty healthy women of childbearing age, 22 second trimester pregnant women, 30 third trimester pregnant women and 10 severe preeclamptic patients were recruited in this study. ADAMTS13 activity was determined by the FRETS-vWF73 assay and vWF antigen (vWF:Ag) levels by an enzyme-linked immunosorbent assay. The results showed that there were statistically significant differences in plasma vWF antigen levels between the severe preeclamptic and third trimester pregnant women, between third and second trimester pregnant women (P<0.05). The third trimester pregnant women had significantly lower plasma ADAMTS13 activity than second trimester pregnant women (P<0.05). Nevertheless, no significant differences in plasma ADAMTS13 activity were found between severe preeclamptic patients and the third trimester pregnant women (P>0.05). In conclusion, plasma ADAMTS13 activity is normal in severe preeclampsia despite the increased vWF:Ag levels. Prothrombotic state is involved in the pathogenesis of severe preeclampsia, as a result of endothelial injury.
A practical approach for rapidly screening antioxidants against superoxide anion radicals from complex mixtures was developed based on the quantitative difference in active compounds before and after their reaction. To test the effectiveness of the approach, seven flavonoids with antioxidative properties were investigated both individually and in a mixture. Using the approach, antioxidants could be rapidly separated and screened with a ranked order of activities in the meantime. The radical scavenging activities were in the following order: quercetin > kaempferol > fisetin > puerarin > luteolin > rutin > baicalein. The order of activity was conducted by comparing the scavenging ratio of the antioxidant, which was completely consistent with the results obtained from the traditional electronic spin resonance. Then, the method was successfully applied to black tea extracts. This approach is fast and convenient for screening, isolating, and analyzing potential antioxidants from a mixture with good quantitative and reproducible ability.
Human trophoblast cells were isolated and cultured in vitro in order to investigate possible pathogenesis of intrauterine infection caused by HCMV. Trophoblast cells were obtained by compound enzymes digestion and discontinuous percoll gradient. Cells and purity were identified by using immunocytochemistry assay with anti-CK7, Vim and beta-hCG antibodies. HCMV AD169 strain replication in isolated trophoblast cells and cell apoptosis were detected at different time points post infection (p.i.). The results showed that highly purified trophoblast cells were obtained. Specific virus replication was increased dramatically at the 24th h p.i., and then increased slowly during 48 h and 72 h. Apoptosis rate of trophoblast cells infected with HCMV was (34.68+/-3.14)% at 24th h p.i., while that in control group was (15.32+/-2.34)% (P<0.05). It was suggested that highly purified trophoblast cells can be isolated by the simplified cell purification method. HCMV can infect human trophoblast cells, and be quickly replicated, resulting in the accelerated apoptosis of human trophoblast cells during early time.
The photosynthetic glycerolipids composition of algae is crucial for structural and physiological aspects. In this work, a comprehensive characterization of the photosynthetic glycerolipids of the diatom Stephanodiscus sp. was carried out by ultra performance liquid chromatography-electrospray ionization-quadrupole-time of flight mass spectrometry (UPLC-ESI-Q-TOF MS). By use of the MS(E) data collection mode, the Q-TOF instrument offered a very viable alternative to triple quadrupoles for precursor ion scanning of photosynthetic glycerolipids and had the advantage of high efficiency, selectivity, sensitivity and mass accuracy. Characteristic fragment ions were utilized to identify the structures and acyl compositions of photosynthetic glycerolipids. Comparing the abundance of fragment ions, it was possible to determine the position of the sn-glycerol-bound fatty acyl chains. As a result, four classes of photosynthetic glycerolipid in the extract of Stephanodiscus sp. were unambiguously identified, including 16 monogalactosyldiacylglycerols (MGDGs), 9 digalactosyldiacylglycerols (DGDGs), 23 sulfoquinovosyldiacylglycerols (SQDGs) and 8 phosphatidylglycerols (PGs). As far as our knowledge, this is the first report on global identification of photosynthetic glycerolipids, including lipid classes, fatty acyl composition within lipids and the location of fatty acids in lipids (sn-1 vs. sn-2), in the extract of marine microalgae by UPLC-ESI-Q-TOF MS directly.
High-performance liquid chromatography/electrospray tandem mass spectrometry was developed to distinguish isomers and compounds of similar structures with different configurations in the rhizomes of Z. cassumunar. Energy-resolved breakdown curves were utilized to differentiate four compounds. Compounds 2 (3R,4S) and 4 (3R,4R) were a pair of stereoisomers which could be distinguished easily by breakdown curves. The breakdown curve of compound 1 was identical to that of compound 2, which suggested that the configuration of compound 1 was (3R,4S) or (3S,4R). The breakdown curve of compound 3 was completely different from those of compounds 1, 2 and 4, and it might be that the configuration of the double bond of compound 3 was different from the other three compounds. Hence, the described method using breakdown curves has great potential in the distinguishing of isomers and compounds of similar structure with different configurations.
A facile method based on high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC/(-)ESI-MSn) has been established for the analyses of polyphenol compounds in the root and stems of Parthenocissus laetevirens. Two characteristic fragments [C3O2 (68 Da) and C2H2O (42 Da)] were utilized for the structural identification of polyphenols. Based on the reference standards, the fragment C3O2 was presented when the compound possessed a 2,3-dihydro-1H-indene-4, 6-diol moiety. Meanwhile, the C2H2O fragment (42 Da) yielded from the resorcinol ring was confirmed by resveratrol and three synthesized compounds identified as (E)-5-styrylbenzene-1,3-diol, (E)-4-styrylphenol and (E)-4-(3,4,5-trimethoxystyryl)phenol. FTICR-MSn was performed to further confirm the structures of the fragments. Overall, 15 polyphenol compounds were characterized. Three polyphenol compounds were initially and tentatively characterized from P. laetevirens for the first time, and one was proposed as a novel compound. Furthermore, a pair of stereoisomers was readily distinguished by breakdown curves, and the trans-, cis-isomers could be identified by HPLC/DAD-UV spectra.
This study examined the anti-viral effect of ursolic acid on guinea pig cytomegalovirus (GPCMV) and explored the steps of viral replication targeted by ursolic acid. Cytopathic effect assay and MTT method were employed to determine the 50% cellular cytotoxicity (CC(50)), 50% effective concentration (EC(50)) and therapeutic index (TI) with GPCMV. To investigate the specific anti-viral effect of ursolic acid at different temperatures and time points, two other medicines, ganciclovir and Jinyebaidu (JYBD), serving as controls, were studied for comparison. Our results showed that the CC50 of ganciclovir, JYBD and ursolic acid were 333.8, 3015.6, 86.7 ?g/mL, respectively; EC(50) of ganciclovir, JYBD and ursolic acid was 48.1, 325.5 and 6.8 ?g/mL, respectively; TI of ganciclovir, JYBD and ursolic acid was 7, 9, 13, respectively. Similar with ganciclovir, ursolic acid could inhibit the viral synthesis, but did not affect the viral adsorption onto and penetration into cells. We are led to conclude that the anti-cytomegalovirus effect of ursolic acid is significantly stronger than ganciclovir or JYBD, and the cytotoxic effect of ursolic acid lies in its ability to inhibit viral synthesis.
Preparative high-speed counter-current chromatography (HSCCC) was successfully applied to the isolation and purification of two macrolactin antibiotics from marine bacterium Bacillus amyloliquefaciens for the first time using stepwise elution with a pair of two-phase solvent systems composed of n-hexane-ethyl acetate-methanol-water at (1:4:1:4, v/v) and (3:4:3:4, v/v). The preparative HSCCC separation was performed on 300 mg of crude sample yielding macrolactin B (22.7 mg) and macrolactin A (40.4 mg) in a one-step separation, with purities over 95% as determined by HPLC. The structures of these compounds were identified by MS, (1)H NMR and (13)C NMR. Our results demonstrated that HSCCC was an efficient technique to separate marine antibiotics, which provide an approach to solve the problem of their sample availability for drug development.
HCA587 (also known as MAGE-C2) is a "cancer-testis" antigen highly expressed in a number of malignancies with unique immunological properties, making it a promising target for tumor immunotherapy. In this report, we demonstrated that HCA587 protein, when formulated with adjuvants CpG-containing oligodeoxynucleotides (CpG ODN) and ISCOM, was capable of inducing a potent cellular and humoral immune response as indicated by the presence of a large number of HCA587-specific, IFN-?-producing CD4(+) T cells and high levels of HCA587-specific antibodies. More importantly, vaccination with HCA587 conferred protection against challenge with HCA587-expressing B16 melanoma in prophylactic and therapeutic settings. In analysis of the mechanisms underlying the protective effect, we showed that the vaccination was followed by enhanced accumulation of tumor-infiltrating lymphocytes (TILs) with enrichment of conventional CD4(+) T cells but reduced representation of Treg cells. Further, the antitumor effect was largely abrogated in mice either depleted of CD4(+) T cells or deficient for IFN-?. These results indicate that HCA587 protein vaccine possesses evident antitumor activity in a mouse model and holds promise for treatment of human cancers.
A facile method based on liquid chromatography coupled with electrospray ionization tandem triple quadrupole mass spectrometry working in selected reaction monitoring mode has been established to analyze toxins in the algae and water samples. Twelve types of toxins (anatoxin, cylindrospermopsin, dinophysistoxin-1, nodularin, okadaic acid, microcystins) were efficiently separated under optimized liquid chromatography coupled with mass spectrometry conditions in the selected reaction monitoring mode. Correlation coefficients of the calibration curves, all felt in the range of 0.9958-0.9998, indicated good linearity. The detection limits of toxins in this method were all lower than 0.20 ng/mL and the quantification limits were in the range from 0.04 to 0.60 ng/mL. Except for anatoxin, cylindrospermopsin, and nodularin, the other toxins recoveries varied from 55.45 to 140.85%. And the relative standard deviations of interday and intraday precision were at 8.61% (n = 5). The high-performance liquid chromatography (HPLC)/electrospray ionization (ESI)-mass spectrometery (MS) method was also successfully applied to analyze the algae and water samples. Owing to its exclusive selectivity and excellent sensitivity, the developed method is a tool for comprehensive analyses of the 12 types of toxins at nanogram levels.
Monomeric (m)Eos2 is an engineered photoactivatable fluorescent protein widely used for super-resolution microscopy. We show that mEos2 forms oligomers at high concentrations and forms aggregates when labeling membrane proteins, limiting its application as a fusion partner. We solved the crystal structure of tetrameric mEos2 and rationally designed improved versions, mEos3.1 and mEos3.2, that are truly monomeric, are brighter, mature faster and exhibit higher photon budget and label density.
Reversibly switchable fluorescent proteins (RSFPs) have attracted widespread interest for emerging techniques including repeated tracking of protein behavior and superresolution microscopy. Among the limited number of RSFPs available, only Dronpa is widely employed for most cell biology applications due to its monomeric and other favorable photochemical properties. Here we developed a series of monomeric green RSFPs with beneficial optical characteristics such as high photon output per switch, high photostability, a broad range of switching rate, and pH-dependence, which make them potentially useful for various applications. One member of this series, mGeos-M, exhibits the highest photon budget and localization precision potential among all green RSFPs. We propose mGeos-M as a candidate to replace Dronpa for applications such as dynamic tracking, dual-color superresolution imaging, and optical lock-in detection.
This study is designed to investigate the feasibility for molecular imaging of endothelial CD81 expression in vitro and in vivo using the CD81-targeted ultrasound contrast agents (UCA). In the in vitro study, murine bEnd.3 cells were stimulated with phenazine methosulfate (PMS), an oxidative stress inducer. Changes in CD81 expression after stimulation were confirmed by Western blotting, tracked by using the targeted UCA and further imaged under ultrasound imaging system with 5 MHz transmit frequency. In the in vivo study, expression of endothelial CD81 proteins in murine carotid artery vessels was studied using high-frequency ultrasound system with 40 MHz transmit frequency. Our results showed that endothelial CD81 expression was gradually up-regulated with the increase of PMS concentration. Correspondingly, the accumulation of targeted UCA was gradually improved and could be inhibited significantly upon addition of free anti-CD81 antibodies. The mean video intensity (grey-level) of stimulated cells and vessels from backscatter of the CD81-targeted UCA was 17.2 (interquartile range [IQR] 15.4-19.8) and 27.2 (IQR 22.4-29.8), significantly greater than that of non-stimulated cells with 9.0 (IQR 8.6-10.8) (p < 0.01) and non-stimulated vessels with 11.3 (IQR 10.4-13.2) (p < 0.01), respectively. In conclusion, CD81-targeted UCA allows noninvasive assessment of the expression levels of CD81 on the vascular endothelium and may provide potential insights into early atherosclerotic plaque detection and treatment monitoring.
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