Chromatography-multiple Reaction Monitoring Mass Spectrometry Research Articles

First-Trimester Preeclampsia-Induced Disturbance in Maternal Blood Serum Proteome: A Pilot Study.

Preeclampsia (PE) is a complex and multifaceted obstetric syndrome characterized by several distinct molecular subtypes. It complicates up to 5% of pregnancies and significantly contributes to maternal and newborn morbidity, thereby diminishing the long-term quality of life for affected women. Due to the widespread dissatisfaction with the effectiveness of existing approaches for assessing PE risk, there is a pressing need for ongoing research to identify newer, more accurate predictors. This study aimed to investigate early changes in the maternal serum proteome and associated signaling pathways. The levels of 125 maternal serum proteins at 11-13 weeks of gestation were quantified using liquid chromatography-multiple reaction monitoring mass spectrometry (LC-MRM MS) with the BAK-125 kit. Ten serum proteins emerged as potential early markers for PE: Apolipoprotein M (APOM), Complement C1q subcomponent subunit B (C1QB), Lysozyme (LYZ), Prothrombin (F2), Albumin (ALB), Zinc-alpha-2-glycoprotein (AZGP1), Tenascin-X (TNXB), Alpha-1-antitrypsin (SERPINA1), Attractin (ATRN), and Apolipoprotein A-IV (APOA4). Notably, nine of these proteins have previously been associated with PE in prior research, underscoring the consistency and reliability of our findings. These proteins play key roles in critical molecular processes, including complement and coagulation cascades, platelet activation, and insulin-like growth factor pathways. To improve the early prediction of PE, a highly effective Support Vector Machine (SVM) model was developed, analyzing 19 maternal serum proteins from the first trimester. This model achieved an area under the curve (AUC) of 0.91, with 87% sensitivity and 95% specificity, and a hazard ratio (HR) of 13.5 (4.6-40.8) with p < 0.001. These findings demonstrate that serum protein-based SVM models possess significantly higher predictive power compared to the routine first-trimester screening test, highlighting their superior utility in the early detection and risk stratification of PE.

Generic Enrichment Method for Liquid Chromatography-Multiple Reaction Monitoring-Mass Spectrometry Assay for Quantitative Measurement of Biological Therapeutics in Serum.

The study aims to leverage the capabilities of Liquid Chromatography-Multiple Reaction Monitoring Mass Spectrometry (LC-MRM), a key technique in quantifying therapeutic proteins in pharmacokinetic studies. The focus is on demonstrating an enrichment method using ProteoMiner beads, which can be integrated with LC-MRM to detect low-abundance biotherapeutics in serum, such as monoclonal antibodies and gene therapy products. The ProteoMiner enrichment method was employed and integrated with LC-MRM. The lower limit of quantification of serum drug substance concentrations was compared with that achievable with immuno-enrichment. The method used commercially available reagents, eliminating the need for assay-specific antibodies and reducing potential bias and development time. The ProteoMiner enrichment method showed comparable performance to immuno-enrichment, meeting traditional assay requirements in terms of precision, accuracy, and specificity. The ProteoMiner enrichment method, when combined with LC-MRM, offers a reliable and efficient alternative to immuno-enrichment for detecting and quantifying low-abundance biotherapeutics in serum. This approach, which uses commercially available reagents, can eliminate the bias and time associated with the development of assay-specific antibodies. It holds significant potential for accelerating pharmacokinetic analysis in both early and late stages of pharmaceutical development.

Recent Research Progress on the Chemical Constituents, Pharmacology, and Pharmacokinetics of Alpinae oxyphyllae Fructus.

Alpinae oxyphyllae fructus (AOF), the dried mature fruit of Alpinia oxyphylla Miquel of the Zingiberaceae family, shows many special pharmacological effects. In recent years, there has been an abundance of research results on AOF. In this paper, the new compounds isolated from AOF since 2018 are reviewed, including terpenes, flavonoids, diarylheptanoids, phenolic acid, sterols, alkanes, fats, etc. The isolation methods that were applied include the microwave-assisted method, response surface method, chiral high-performance liquid chromatography-multiple reaction monitoring-mass spectrometry (HPLC-MRM-MS) analytical method, ultra-high-performance liquid chromatography-quadrupole-electrostatic field orbitrap high-resolution mass spectrometry (UPLC-Orbitrap-HRMS) method, ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method, hot water leaching method, ethanol leaching method, and so on. Additionally, the pharmacological effects of AOF found from 2018 to 2024 are also summarized, including neuroprotection, regulation of metabolic disorders, antioxidant activity, antiapoptosis, antiinflammatory activity, antidiabetic activity, antihyperuricemia, antiaging, antidiuresis, immune regulation, anti-tumor activity, renal protection, hepatoprotection, and anti-asthma. This paper provides a reference for further research on AOF.

A Reverse Thinking Based on Partially Methylated Aldononitrile Acetates to Analyze Glycoside Linkages of Polysaccharides Using Liquid Chromatography-Multiple Reaction Monitoring Mass Spectrometry.

Glycoside linkage analyses of medicine and food homologous plant polysaccharides have always been a key point and a difficulty of structural characterization. The gas chromatography-mass spectrometry (GC-MS) method is one of the commonly used traditional techniques to determine glycoside linkages via partially methylated alditol acetates and aldononitrile acetates (PMAAs and PMANs). Due to the simplicity of derivatization and the highly structural asymmetry of PMANs, reverse thinking is proposed using liquid chromatography-electrospray ionization-multiple reaction monitoring mass spectrometry (LC-ESI-MRM-MS) for the first time to directly determine the neutral and acidic glycosyl linkages of polysaccharides. The complete characterization of glycoside linkages deduced from PMANs was achieved using a combination of tR values, characteristic MRM ion pairs, diagnostic ESI+-MS/MS fragmentation ions (DFIs), and optimal collision energy (OCE). The DFI and OCE parameters were confirmed to be effective for the auxiliary discrimination of some isomers of the PMANs. The practicality of LC-ESI+-MRM-MS was further verified by analyzing the glycoside linkages of polysaccharides in five medicine and food homologous plants. This method can serve as an alternative to GC-MS for the simultaneous determination of neutral and acidic glycosyl linkages in polysaccharides.

Pseudotargeted lipidomics analysis of scoparone on glycerophospholipid metabolism in non-alcoholic steatohepatitis mice by LC-MRM-MS.

As the inflammatory subtype of nonalcoholic fatty liver disease (NAFLD), the progression of nonalcoholic steatohepatitis (NASH) is associated with disorders of glycerophospholipid metabolism. Scoparone is the major bioactive component in Artemisia capillaris which has been widely used to treat NASH in traditional Chinese medicine. However, the underlying mechanisms of scoparone against NASH are not yet fully understood, which hinders the development of effective therapeutic agents for NASH. Given the crucial role of glycerophospholipid metabolism in NASH progression, this study aimed to characterize the differential expression of glycerophospholipids that is responsible for scoparone's pharmacological effects and assess its efficacy against NASH. Liquid chromatography-multiple reaction monitoring-mass spectrometry (LC-MRM-MS) was performed to get the concentrations of glycerophospholipids, clarify mechanisms of disease, and highlight insights into drug discovery. Additionally, pathologic findings also presented consistent changes in high-fat diet-induced NASH model, and after scoparone treatment, both the levels of glycerophospholipids and histopathology were similar to normal levels, indicating a beneficial effect during the observation time. Altogether, these results refined the insights on the mechanisms of scoparone against NASH and suggested a route to relieve NASH with glycerophospholipid metabolism. In addition, the current work demonstrated that a pseudotargeted lipidomic platform provided a novel insight into the potential mechanism of scoparone action.

Quantitative Proteomics of Maternal Blood Plasma in Isolated Intrauterine Growth Restriction

Intrauterine growth restriction (IUGR) remains a significant concern in modern obstetrics, linked to high neonatal health problems and even death, as well as childhood disability, affecting adult quality of life. The role of maternal and fetus adaptation during adverse pregnancy is still not completely understood. This study aimed to investigate the disturbance in biological processes associated with isolated IUGR via blood plasma proteomics. The levels of 125 maternal plasma proteins were quantified by liquid chromatography-multiple reaction monitoring mass spectrometry (LC-MRM MS) with corresponding stable isotope-labeled peptide standards (SIS). Thirteen potential markers of IUGR (Gelsolin, Alpha-2-macroglobulin, Apolipoprotein A-IV, Apolipoprotein B-100, Apolipoprotein(a), Adiponectin, Complement C5, Apolipoprotein D, Alpha-1B-glycoprotein, Serum albumin, Fibronectin, Glutathione peroxidase 3, Lipopolysaccharide-binding protein) were found to be inter-connected in a protein–protein network. These proteins are involved in plasma lipoprotein assembly, remodeling, and clearance; lipid metabolism, especially cholesterol and phospholipids; hemostasis, including platelet degranulation; and immune system regulation. Additionally, 18 proteins were specific to a particular type of IUGR (early or late). Distinct patterns in the coagulation and fibrinolysis systems were observed between isolated early- and late-onset IUGR. Our findings highlight the complex interplay of immune and coagulation factors in IUGR and the differences between early- and late-onset IUGR and other placenta-related conditions like PE. Understanding these mechanisms is crucial for developing targeted interventions and improving outcomes for pregnancies affected by IUGR.

Assessment of a 60-Biomarker Health Surveillance Panel (HSP) on Whole Blood from Remote Sampling Devices by Targeted LC/MRM-MS and Discovery DIA-MS Analysis.

Telehealth, accessing healthcare and wellness remotely, should be a cost-effective and efficient way for individuals to receive care. The convenience of having a reliable remote collection device for blood tests will facilitate access to precision medicine and healthcare. Herein, we tested a 60-biomarker health surveillance panel (HSP), containing 35 FDA/LDT assays and covering at least 14 pathological states, on 8 healthy individuals' ability to collect their own capillary blood from a lancet finger prick and directly compared it to the traditional phlebotomist venous blood and plasma collection methods. All samples were spiked with 114 stable-isotope-labeled (SIL) HSP peptides and quantitatively analyzed by liquid chromatography-multiple reaction monitoring-mass spectrometry (LC/MRM-MS) scheduled method targeting 466 transitions from 114 HSP peptides and by a discovery data-independent acquisition mass spectrometry (DIA-MS) method. The average peak area ratio (PAR) of the HSP quantifier peptide transitions from all 8 volunteers' capillary blood (n = 48), venous blood (n = 48), and matched plasma (n = 24) was <20% coefficients of variation (CV). Heat map analysis of all 8 volunteers demonstrated that each individual had a unique biosignature. Biological replicates from capillary blood and venous blood clustered within each volunteer in k-means clustering analysis. Pearson statistical analysis of the three biofluids indicated that there was >90% similarity. Discovery DIA-MS analysis of the same samples using a plasma spectral library and a pan-human spectral library identified 1121 and 4661 total proteins, respectively. In addition, at least 122 FDA-approved biomarkers were identified. DIA-MS analysis reproducibly quantitated (<30% CV) ∼600-700 proteins in capillary blood, ∼800 proteins in venous blood, and ∼300-400 proteins in plasma, demonstrating that an expansive biomarker panel is possible with current mass spectrometry technology. Both targeted LC/MRM-MS and discovery DIA-MS analysis of whole blood collected on remote sampling devices are viable options for personal proteome biosignature stratification in precision medicine and precision health.

Integrating Proteomics and Lipidomics for Evaluating the Risk of Breast Cancer Progression: A Pilot Study.

Metastasis is a serious and often life-threatening condition, representing the leading cause of death among women with breast cancer (BC). Although the current clinical classification of BC is well-established, the addition of minimally invasive laboratory tests based on peripheral blood biomarkers that reflect pathological changes in the body is of utmost importance. In the current study, the serum proteome and lipidome profiles for 50 BC patients with (25) and without (25) metastasis were studied. Targeted proteomic analysis for concertation measurements of 125 proteins in the serum was performed via liquid chromatography-multiple reaction monitoring mass spectrometry (LC-MRM MS) using the BAK 125 kit (MRM Proteomics Inc., Victoria, BC, Canada). Untargeted label-free lipidomic analysis was performed using liquid chromatography coupled to tandem mass-spectrometry (LC-MS/MS), in both positive and negative ion modes. Finally, 87 serum proteins and 295 lipids were quantified and showed a moderate correlation with tumor grade, histological and biological subtypes, and the number of lymph node metastases. Two highly accurate classifiers that enabled distinguishing between metastatic and non-metastatic BC were developed based on proteomic (accuracy 90%) and lipidomic (accuracy 80%) features. The best classifier (91% sensitivity, 89% specificity, AUC = 0.92) for BC metastasis diagnostics was based on logistic regression and the serum levels of 11 proteins: alpha-2-macroglobulin, coagulation factor XII, adiponectin, leucine-rich alpha-2-glycoprotein, alpha-2-HS-glycoprotein, Ig mu chain C region, apolipoprotein C-IV, carbonic anhydrase 1, apolipoprotein A-II, apolipoprotein C-II and alpha-1-acid glycoprotein 1.

The generation of 5-N-glycolylneuraminic acid as a consequence of high levels of reactive oxygen species.

The presence of N-glycolylneuraminic acid (Neu5Gc), a non-human sialic acid in cancer patients, is currently attributed to the consumption of red meat. Excess dietary red meat has been considered a risk factor causing chronic inflammation and for the development of cancers. However, it remains unknown whether Neu5Gc can be generated via a chemical reaction rather than via a metabolic pathway in the presence of high levels of reactive oxygen species (ROS) found in the inflammatory and tumor environments. In this study, the conversion of N-acetylneuraminic acid (Neu5Ac) to Neu5Gc has been assessed in vitro under conditions mimicking the hydroxyl radical-rich humoral environment found in inflammatory and cancerous tissues. As a result, Neu5Gc has been detected via liquid chromatography-multiple reaction monitoring mass spectrometry. Furthermore, this conversion has also been found to take place in serum biomatrix containing ROS and in cancer cell cultures with induced ROS production.

Targeting NAD+ metabolism of hepatocellular carcinoma cells by lenvatinib promotes M2 macrophages reverse polarization, suppressing the HCC progression.

Lowered nicotinamide adenine dinucleotide (NAD+) levels in tumor cells drive tumor hyperprogression during immunotherapy, and its restoration activates immune cells. However, the effect of lenvatinib, a first-line treatment for unresectable hepatocellular carcinoma (HCC), on NAD+ metabolism in HCC cells, and the metabolite crosstalk between HCC and immune cells after targeting NAD+ metabolism of HCC cells remain unelucidated. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) and ultra-high-performance liquid chromatography multiple reaction monitoring-mass spectrometry (UHPLC-MRM-MS) were used to detect and validate differential metabolites. RNA sequencing was used to explore mRNA expression in macrophages and HCC cells. HCC mouse models were used to validate the effects of lenvatinib on immune cells and NAD+ metabolism. The macrophage properties were elucidated using cell proliferation, apoptosis, and co-culture assays. In silico structural analysis and interaction assays were used to determine whether lenvatinib targets tet methylcytosine dioxygenase 2 (TET2). Flow cytometry was performed to assess changes in immune cells. Lenvatinib targeted TET2 to synthesize and increase NAD+ levels, thereby inhibiting decomposition in HCC cells. NAD+ salvage increased lenvatinib-induced apoptosis of HCC cells. Lenvatinib also induced CD8+ T cells and M1 macrophages infiltration in vivo. And lenvatinib suppressed niacinamide, 5-Hydroxy-L-tryptophan and quinoline secretion of HCC cells, and increased hypoxanthine secretion, which contributed to proliferation, migration and polarization function of macrophages. Consequently, lenvatinib targeted NAD+ metabolism and elevated HCC-derived hypoxanthine to enhance the macrophages polarization from M2 to M1. Glycosaminoglycan binding disorder and positive regulation of cytosolic calcium ion concentration were characteristic features of the reverse polarization. Targeting HCC cells NAD+ metabolism by lenvatinib-TET2 pathway drives metabolite crosstalk, leading to M2 macrophages reverse polarization, thereby suppressing HCC progression. Collectively, these novel insights highlight the role of lenvatinib or its combination therapies as promising therapeutic alternatives for HCC patients with low NAD+ levels or high TET2 levels.

Deciphering Phenotypes from Protein Biomarkers for Translational Research with PIPER.

Liquid chromatography-multiple reaction monitoring mass spectrometry (LC-MRM) has widespread clinical use for detection of inborn errors of metabolism, therapeutic drug monitoring, and numerous other applications. This technique detects proteolytic peptides as surrogates for protein biomarker expression, mutation, and post-translational modification in individual clinical assays and in cancer research with highly multiplexed quantitation across biological pathways. LC-MRM for protein biomarkers must be translated from multiplexed research-grade panels to clinical use. LC-MRM panels provide the capability to quantify clinical biomarkers and emerging protein markers to establish the context of tumor phenotypes that provide highly relevant supporting information. An application to visualize and communicate targeted proteomics data will empower translational researchers to move protein biomarker panels from discovery to clinical use. Therefore, we have developed a web-based tool for targeted proteomics that provides pathway-level evaluations of key biological drivers (e.g., EGFR signaling), signature scores (representing phenotypes) (e.g., EMT), and the ability to quantify specific drug targets across a sample cohort. This tool represents a framework for integrating summary information, decision algorithms, and risk scores to support Physician-Interpretable Phenotypic Evaluation in R (PIPER) that can be reused or repurposed by other labs to communicate and interpret their own biomarker panels.

Direct acetylation for full analysis of polysaccharides in edible plants and fungi using reverse phase liquid chromatography-multiple reaction monitoring mass spectrometry

It is vitally important to characterize polysaccharides by monosaccharide composition method. In this study, a direct acetylation strategy combined with reversed-phase liquid chromatography electrospray tandem multiple reaction monitoring mass spectrometry (RPLC-ESI-MRM-MS) was developed for simultaneous determination of 8 aldoses (Glc, Gal, Man, Ara, Xyl, Rib, Rha and Fuc), a ketose (Fru), 2 alditols (Glc-ol and Man-ol) and 2 uronic acids (GlcA and GalA) on a high-pressure resistant reversed-phase column. Employing 1-MeIm as catalyst for direct acetylation, even though no DMSO was used to inhibit the transformation of configurations, each carbohydrate still produced a single chromatographic peak in RPLC conditions due to the ɑ- and β- isomers merged together. Except for Fru and Man, all the other 11 carbohydrates were base-line separated in a 1.7 µm CYANO column. Therefore, correction factor method is further proposed to perfectly solve co-elution problem of Fru and Man because of occurrence of a specific Q3 ion for aldoses rather than ketose. The result was verified on a 1.7 µm Fluoro-Phenyl column with a full separation of Fru and Man. Herein, the established direct acetylation as followed RPLC-ESI-MRM-MS method was successfully applied for compositional analysis of complex polysaccharides from edible plants and fungi.

Accelerating the Validation of Endogenous On-Target Engagement and In Cellulo Kinetic Assessment for Covalent Inhibitors of KRASG12C in Early Drug Discovery.

Covalent inhibition is a valuable modality in drug discovery because of its potential ability in decoupling pharmacokinetics from pharmacodynamics by prolonging the residence time of the drug on the target of interest. This increase in target occupancy is limited only by the rate of target turnover. However, a limitation in such studies is to translate the in vitro inhibition assessment to the appropriate in cellulo target engagement parameter by covalent probes. Estimation of such parameters is often impeded by the low-throughput nature of current probe-free approaches. In this study, an ultra-performance liquid chromatography-multiple reaction monitoring mass spectrometry platform was utilized to develop a targeted proteomics workflow that can evaluate cellular on-target engagement of covalent molecules in an increased throughput manner. This workflow enabled a throughput increase of 5-10 fold when compared to traditional nanoLC-based proteomics studies. To demonstrate the applicability of the method, KRASG12C was used as a model system to investigate the interaction of an irreversible covalent small molecule, compound 25, both in vitro and in cellulo. Initial biochemical studies confirmed that the small molecule forms an adduct with the targeted cysteine on the protein, as assessed at the level of both intact protein and on the target peptide. In cellulo studies were carried out to quantify target engagement and allele selectivity assessment for the small molecule in the heterozygous NCI-H358 cell line for KRASG12C with respect to the WT type protein. The workflow enabled evaluation of in vitro and in cellulo target engagement kinetics, providing mechanistic insights into the irreversible mode of inhibition. In summary, the method has the potential for target agnostic application in the assessment of on-target engagement of covalent probes compatible with the high-throughput requirements of early drug discovery.

Evaluation of the Major Seed Storage Proteins, the Conglutins, Across Genetically Diverse Narrow-Leafed Lupin Varieties

Lupin seeds have an excellent nutritional profile, including a high proportion of protein and dietary fiber. These qualities make lupin seeds an ideal candidate to help meet the growing global demand for complementary sources of protein. Of consequence to this application, there are nutritional and antinutritional properties assigned to the major lupin seed storage proteins—referred to as α-, β-, δ- and γ-conglutins The variation in the abundance of these protein families can impact the nutritional and bioactive properties of different lupin varieties. Hence, exploring the conglutin protein profiles across a diverse range of lupin varieties will yield knowledge that can facilitate the selection of superior genotypes for food applications or lupin crop improvement. To support this knowledge generation, discovery proteomics was applied for the identification of the 16 known conglutin subfamilies from 46 domestic and wild narrow-leafed lupin (NLL) genotypes. Consequently, the diversity of abundance of these proteins was evaluated using liquid chromatography–multiple reaction monitoring-mass spectrometry (LC–MRM-MS). This comparative study revealed a larger variability for the β- and δ-conglutin content across the lines under study. The absence/lower abundance of the β2- to β6-conglutin subfamilies in a subset of the domesticated cultivars led to substantially lower overall levels of the allergenic β-conglutin content in these NLLs, for which the elevation of the other conglutin families were observed. The diversity of the conglutin profiles revealed through this study—and the identification of potential hypoallergenic genotypes—will have great significance for lupin allergic consumers, food manufactures as well as grain breeders through the future development of lupin varieties with higher levels of desirable bioactive proteins and lower allergen content.

Prodynorphin and Proenkephalin in Cerebrospinal Fluid of Sporadic Creutzfeldt-Jakob Disease.

Proenkephalin (PENK) and prodynorphin (PDYN) are endogenous opioid peptides mainly produced in the striatum and, to a lesser extent, in the cerebral cortex. Dysregulated metabolism and altered cerebrospinal fluid (CSF) levels of PENK and PDYN have been described in several neurodegenerative diseases. However, no study to date investigated these peptides in the CSF of sporadic Creutzfeldt–Jakob disease (sCJD). Using liquid chromatography-multiple reaction monitoring mass spectrometry, we evaluated the CSF PDYN- and PENK-derived peptide levels in 25 controls and 63 patients with sCJD belonging to the most prevalent molecular subtypes (MM(V)1, VV2 and MV2K). One of the PENK-derived peptides was significantly decreased in each sCJD subtype compared to the controls without a difference among subtypes. Conversely, PDYN-derived peptides were selectively decreased in the CSF of sCJD MV2K, a subtype with a more widespread overall pathology compared to the sCJD MM(V)1 and the VV2 subtypes, which we confirmed by semiquantitative analysis of cortical and striatal neuronal loss and astrocytosis. In sCJD CSF PENK and PDYN were associated with CSF biomarkers of neurodegeneration but not with clinical variables and showed a poor diagnostic performance. CSF PDYN and PENK-derived peptides had no significant diagnostic and prognostic values in sCJD; however, the distinct marker levels between molecular subtypes might help to better understand the basis of phenotypic heterogeneity determined by divergent neuronal targeting.

Liquid Chromatography-Multiple Reaction Monitoring-Mass Spectrometry Assay for Quantitative Measurement of Therapeutic Antibody Cocktail REGEN-COV Concentrations in COVID-19 Patient Serum.

REGEN-COV is a cocktail of two human IgG1 monoclonal antibodies (REGN10933 + REGN10987) that targets severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein and has shown great promise to reduce the SARS-CoV-2 viral load in COVID-19 patients enrolled in clinical studies. A liquid chromatography-multiple reaction monitoring-mass spectrometry (LC-MRM-MS)-based method, combined with trypsin and rAspN dual enzymatic digestion, was developed for the determination of total REGN10933 and total REGN10987 concentrations in several hundreds of pharmacokinetic (PK) serum samples from COVID-19 patients participating in phase I, II, and III clinical studies. The performance characteristics of this bioanalytical assay were evaluated with respect to linearity, accuracy, precision, selectivity, specificity, and analyte stability before and after enzymatic digestion. The developed LC-MRM-MS assay has a dynamic range from 10 to 2000 μg/mL antibody drug in the human serum matrix, which was able to cover the serum drug concentration from day 0 to day 28 after drug administration in two-dose groups for the clinical PK study of REGEN-COV. The concentrations of REGEN-COV in the two-dose groups measured by the LC-MRM-MS assay were comparable to the concentrations measured by a fully validated electrochemiluminescence (ECL) immunoassay.

Identification and Quantitation of Amylase Trypsin Inhibitors Across Cultivars Representing the Diversity of Bread Wheat.

α-Amylase/trypsin inhibitors (ATIs) may have a role in nonceliac wheat sensitivity (NCWS) and celiac disease (CD), but the ATI content and diversity across a range of wheat cultivars are not well characterized. Discovery proteomics was used to detect ATIs across two wheat cultivars: Chara and Magenta. Comprehensive mapping of detected ATIs with the ATIs from the recently published wheat genome RefSeq v1.0 shows the presence of three major subclasses: monomeric (9%), dimeric (61%), and chloroform-methanol (CM) type (30%). Subsequently, the level of 18 ATI isoforms (63 peptides) grouped into four subtypes was monitored across 15 commercial wheat cultivars and the eight parental lines from a multiparent advanced-generation intercross (MAGIC) population using liquid chromatography-multiple reaction monitoring-mass spectrometry (LC-MRM-MS). The ATI content of wheat cultivars Janz, Sunvale, Diamond Bird, and Longreach Scout was significantly lower than that of other wheat cultivars. The MAGIC parental cultivars Baxter and Xiaoyan 54 contain higher levels (∼115% relative to the average wheat ATI content), whereas cultivar Pastor contained the lowest levels (∼87%). Comprehensive sequence analysis, annotation, chromosomal locations, and epitope mapping enabled us to build an LC-MRM-MS method to monitor and quantify the immunostimulatory ATI proteins potentially related to NCWS, autoimmune diseases, and metabolic disorders. This provides an opportunity to select wheat cultivars with significantly lower levels of ATIs.

Assessment of Serological Early Biomarker Candidates for Lung Adenocarcinoma by using Multiple Reaction Monitoring-Mass Spectrometry.

Plasma markers that enable diagnosis in the early stage of lung cancer is not discovered. A liquid chromatography multiple reaction monitoring-mass spectrometry (LC-MRM-MS) assay for identifying potential early marker proteins for lung adenocarcinoma is developed. LC-MRM-MS assay is used for measuring the level of 35 candidate peptides in plasma from 102 lung adenocarcinoma patients (including n = 50, 16, 24, and 12 in stage I, II, III, and IV, respectively.) and 84healthy controls. Stable isotope labeled standard peptides are synthesized to accurately measure the amount of these proteins. Seven proteins are able to distinguish stage I patients from controls. These proteins are combined in to a protein marker panel which improve the sensitivity to discriminate stage I patients from controls with cross-validated area under the curve = 0.76. Besides, it is found that low expression of eukaryotic initiation factor 4A-I and high expression of lumican show significantly poor prognosis in overall survival (p = 0.012 and 0.0074, respectively), which may be used as prognostic biomarkers for lung cancer. Proteins highlighted here may be used for early detection of lung adenocarcinoma or therapeutics development after validation in a larger cohort.

Cervicovaginal fluid proteomic analysis to identify potential biomarkers for preterm birth

Spontaneous preterm birth is a leading cause of neonatal morbidity and mortality. Early identification of at-risk women by reliable screening tests could reduce the spontaneous preterm birth rate, but conventional methods such as obstetrical history and maternal cervical length screening identify only a minority of spontaneous preterm birth cases. Cervicovaginal fluid might prove to be a useful, readily available biological fluid for identifying spontaneous preterm birth biomarkers. The objective of the study was to identify cervicovaginal fluid biomarkers of early spontaneous preterm birth in a high-risk cohort of pregnant women with a history of spontaneous preterm birth using targeted and shotgun proteomic analyses. A nested case control study (cases were spontaneous preterm birth <34 weeks in the current pregnancy; controls were spontaneous labor and delivery at 39-41 weeks) was performed using cervicovaginal fluid samples collected at 3 study visits (100/7 to 186/7 weeks, 190/7 to 236/7 weeks, and 280/7 to 316/7 weeks). All participants had a history of at least 1 prior spontaneous preterm birth. Targeted proteomic analysis was performed using a stable isotope-labeled proteome derived from endocervical and vaginal mucosal cells. This served as a standard to quantitate candidate protein levels in individual cervicovaginal fluid samples from the second and third study visits using liquid chromatography-multiple reaction monitoring mass spectrometry. The ratio of endogenous peptide area/stable isotope-labeled proteome-derived peptide area was used to measure levels of 42 peptides in 22 proteins. To maximize biomarker discovery in the cervicovaginal fluid samples, shotgun proteomic analysis also was performed utilizing liquid chromatography and ion trap mass spectrometry. A validation study was performed in second-trimester cervicovaginal fluid samples from an independent study group (12 spontaneous preterm birth cases, 19 term delivery controls) using enzyme-linked immunosorbent assay for 5 proteins expressed at higher levels in spontaneous preterm birth cases compared with controls in targeted or shotgun proteomic analyses. For targeted proteomics, cervicovaginal fluid samples from 33 cases and 32 controls at 190/7 to 236/7 weeks and 16 cases and 14 controls at 280/7 to 316/7 weeks from the same pregnancies were analyzed. When samples were compared between cases and controls, the relative abundance of 5 proteins was greater (P= .02-.05) in cases at both visits, while the relative abundance of 1 protein was lower (P= .03) in cases at both visits. For shotgun proteomics analyses, cervicovaginal fluid samples were pooled for 9 spontaneous preterm birth cases and 9 term delivery controls at each study visit. Shotgun proteomics yielded 28 proteins that were detected at levels >2 times higher and 1 protein that was detected at a level <0.5 times lower in spontaneous preterm birth cases compared with controls at all 3 study visits. Validation enzyme-linked immunosorbent assay for 5 proteins that were detected at higher levels in cervicovaginal fluid samples from spontaneous preterm birth cases compared with term delivery controls in proteomics analyses did not demonstrate statistically significant differences between spontaneous preterm birth cases and controls. Potential biomarkers of spontaneous preterm birth were identified by targeted and shotgun proteomics analyses in cervicovaginal fluid samples from high-risk, asymptomatic women. Many of the proteins detected at higher levels in cervicovaginal fluid samples from spontaneous preterm birth cases are extracellular matrix proteins and/or regulate cell membrane physiology. These proteins have substantial biological interest, but validation enzyme-linked immunosorbent assay for 5 of these proteins did not yield clinically useful biomarkers for spontaneous preterm birth.

Liquid Chromatography-Multiple Reaction Monitoring Mass Spectrometry Quantification of Extracellular Vesicles Signaling Proteins in placental cells under different physiological conditions

Perinatal sodium overload induces endothelial dysfunction in adult offspring, but the underlying mechanisms are not fully known. The involvement of tissue renin-angiotensin system on high sodium-programmed endothelial dysfunction was examined.Acetylcholine and angiotensin I and II responses were analyzed in aorta and mesenteric resistance arteries from 24-week-old male offspring of normal-salt (O-NS, 1.3% NaCl) and high-salt (O-HS, 8% NaCl) fed dams. COX-2 expression, O2– production and angiotensin converting enzyme (ACE) activity were determined. A separated O-HS was treated with losartan (15 mg kg−1/day) for eight weeks.Compared to O-NS, O-HS were normotensive. Acetylcholine-induced relaxation was impaired in O-HS arteries, which was improved by tempol, apocynin or indomethacin. The angiotensin I-induced contraction was greater in O-HS arteries, whereas the angiotensin II responses were unchanged. ACE activity, O2– production and COX-2 expression were increased in O-HS arteries. In this group, the increased O2– production was inhibited by apocynin or losartan. Chronic losartan decreased COX-2 expression and restored the endothelium-dependent vasodilation in O-HS.Our findings reiterate that perinatal sodium overload programs endothelial dysfunction in adult offspring through a blood pressure-independent mechanism. Our results also suggest that vascular angiotensin II is the main mediator of high sodium-programmed endothelial dysfunction, promoting COX-2 expression and oxidative stress.