Publications by authors named "Borchers C"

Quantifying urinary catecholamines and metanephrines is essential for the clinical screening and diagnosis of neuroendocrine tumours. HPLC with electrochemical detection (HPLC-ECD) is commonly used for this type of analysis but requires extensive sample cleanup. Simple and rapid dilute-and-shoot LC-multiple-reaction monitoring (MRM)-MS assays have been developed for quantitating these analytes in urine but have not yet been validated according to the Clinical and Laboratory Standards Institute (CLSI) guidelines.

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The National Cancer Institute's Clinical Proteomics Tumor Analysis Consortium (CPTAC) was established to address the need for improved design, standardization, and validation of proteomics assays to enable better translation of biomarkers from the analytical lab to the clinic. Here, we applied CPTAC guidelines to characterize quantitative mass spectrometry (MS) assays in a new multiple reaction monitoring (MRM) proteomics panel. The panel of 50 proteins was developed in response to a previous study that identified a proteomic profile of altered translational control associated with response to a new cancer drug.

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Iron regulatory protein 2 (IRP2), a post-transcriptional regulator of cellular iron metabolism has been associated with susceptibility to chronic obstructive pulmonary disease (COPD). Resistive breathing (RB) is the hallmark of the pathophysiology of obstructive airway diseases, especially during exacerbations, where increased mechanical stress is imposed on the lung. We have previously shown that RB, through tracheal banding, mimicking severe airway obstruction, induces pulmonary inflammation and injury in previously healthy mice.

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Article Synopsis
  • Multiple analytical techniques were combined to analyze the NIST human plasma reference material SRM 1950, aiming to provide a validated list of metabolite concentration benchmarks for the metabolomics community.
  • The study utilized four platforms—high-resolution NMR spectroscopy, direct injection tandem MS, liquid chromatography tandem MS, and inductively coupled plasma MS—resulting in accurate measurements for 728 unique metabolites and an additional 330 identified through literature mining.
  • A comprehensive database (SRM1950-DB) with 1,058 metabolites, including information like structures and concentrations, is available online, representing the most thorough quantitative characterization of SRM 1950 to date.
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This study provides real-world evidence for DCIS, a disease for which currently no molecular tools or biomarkers exist, and gives an unbiased, comprehensive, and deep proteomic profile, identifying >380 actionable targets.

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Here we show that when using a mix of 274 light synthetic peptide standards (NAT) as surrogates for 270 human plasma proteins, as well as stable isotope-labelled standards (SIS) as normalizers (both from MRM Proteomics Inc.) for targeted quantitative analysis by liquid chromatography multiple reaction monitoring mass spectrometry (LC/MRM-MS), the Seer Proteograph™ platform allowed for the enrichment and absolute quantitation of up to an additional 62 targets (median) compared to two standard proteomic workflows without enrichment, representing an increase of 44%. The nanoparticle-based fractionation workflow resulted in improved reproducibility compared to a traditional proteomic workflow with no fractionation (median 8.

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With immuno-oncology becoming the standard of care for a variety of cancers, identifying biomarkers that reliably classify patient response, resistance, or toxicity becomes the next critical barrier towards improving care. Multi-parametric, multi-omics, and computational platforms generating an unprecedented depth of data are poised to usher in the discovery of increasingly robust biomarkers for enhanced patient selection and personalized treatment approaches. Deciding which developing technologies to implement in clinical settings ultimately, applied either alone or in combination, relies on weighing pros and cons, from minimizing patient sampling to maximizing data outputs, and assessing reproducibility and representativeness of findings, while lessening data fragmentation towards harmonization.

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Introduction: Biomarker discovery is increasingly moving from single omics to multiomics, as well as from multi-cell omics to single-cell omics. These transitions have increasingly adopted digital transformation technologies to accelerate the progression from data to insight. Here, we will discuss the concept of 'digitalomics' and how digital transformation directly impacts biomarker discovery.

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Dysregulation of the mitogen-activated protein kinase interacting kinases 1/2 (MNK1/2)-eukaryotic initiation factor 4E (eIF4E) signaling axis promotes breast cancer progression. MNK1 is known to influence cancer stem cells (CSCs); self-renewing populations that support metastasis, recurrence, and chemotherapeutic resistance, making them a clinically relevant target. The precise function of MNK1 in regulating CSCs, however, remains unexplored.

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The olfactory bulb (OB), a major structure of the limbic system, has been understudied in human investigations of psychopathologies such as depression. To explore more directly the molecular features of the OB in depression, a global comparative proteome analysis was carried out with human post-mortem OB samples from 11 males having suffered from depression and 12 healthy controls. We identified 188 differentially abundant proteins (with adjusted p < 0.

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Engaging in research experiences as a high school or undergraduate student interested in science, technology, engineering, and mathematics (STEM) is pivotal for their academic and professional development. A structured teaching framework can help cultivate a student's curiosity and passion for learning and research. In this study, an eight-week training program was created to encompass fundamental molecular biology principles and hands-on laboratory activities.

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Article Synopsis
  • - Adult stem cells are crucial for repairing and maintaining tissues, remaining inactive in slow-turnover tissues like skeletal muscle but capable of becoming active when needed.
  • - Research shows that the PAX7/NEDD4L signaling pathway inhibits muscle stem cell activation in healthy skeletal muscle, with PAX7 promoting the E3 ubiquitin ligase NEDD4L that helps keep these cells quiescent.
  • - Deleting Nedd4L from muscle stem cells leads to increased activity of cell cycle and muscle differentiation genes, and the expression of doublecortin, indicating that Nedd4L is vital for maintaining stem cell inactivity in adult mice.
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  • Capivasertib is an FDA-approved AKT inhibitor used with fulvestrant for treating HR+, HER2-negative breast cancer patients with specific PI3K pathway mutations, showing less than 30% response rates in early trials.
  • In a study analyzing 16 patient tumors, differences in protein levels were observed between those who benefited from capivasertib treatment and those who did not, with findings indicating that higher translational activity correlates with resistance to the drug.
  • The results suggest that profiling protein concentrations could help refine patient selection for capivasertib therapy, improving outcomes even in genetically preselected patients.
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Malaria is a serious vector-borne disease characterized by periodic episodes of high fever and strong immune responses that are coordinated with the daily synchronized parasite replication cycle inside RBCs. As immune cells harbor an autonomous circadian clock that controls various aspects of the immune response, we sought to determine whether the intensity of the immune response to Plasmodium spp., the parasite causing malaria, depends on time of infection.

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To prevent doping practices in sports, the World Anti-Doping Agency implemented the Athlete Biological Passport (ABP) program, monitoring biological variables over time to indirectly reveal the effects of doping rather than detect the doping substance or the method itself. In the context of this program, a highly multiplexed mass spectrometry-based proteomics assay for 319 peptides corresponding to 250 proteins was developed, including proteins associated with blood-doping practices. "Baseline" expression profiles of these potential biomarkers in capillary blood (dried blood spots (DBS)) were established using multiple reaction monitoring (MRM).

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Article Synopsis
  • A decade ago, multiomics analysis was developed for early disease detection and personalized health care, but its high costs and complex data have limited its practicality.
  • This case report introduces a more feasible approach using fewer measurements and annual monitoring, which successfully detected a precancerous pancreatic tumor in a patient.
  • The patient’s annual blood tests revealed significant changes that led to imaging and ultimately surgery, confirming the tumor was precancerous and showcasing the potential of blood-based monitoring for early cancer diagnosis.
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Nucleic acids, lipids, and other cell components can be found within different types of extracellular vesicles (EVs), which include apoptotic bodies (ABs), large extracellular vesicles (LEVs), and small extracellular vesicles (SEVs). Release of LEVs from cells can be reduced by genetic or pharmacological inhibition of the enzyme acid sphinogomyelinase (aSMase), and indeed several studies have demonstrated a role for the clinically approved aSMase inhibitor imipramine in blocking LEV release, including in response to UVB exposure. Given that exposure of keratinocytes to UVB radiation results in the generation of UVR photoproducts in DNA that can subsequently be found in association with ABs and SEVs, we examined how imipramine impacts the release of extracellular DNA containing UVR photoproducts at an early time point after UVR exposure.

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Apolipoprotein E (apoE), a polymorphic plasma protein, plays a pivotal role in lipid transportation. The human apoE gene possesses three major alleles (ε2, ε3, and ε4), which differ by single amino acid (cysteine to arginine) substitutions. The ε4 allele represents the primary genetic risk factor for Alzheimer's disease (AD), whereas the ε2 allele protects against the disease.

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The cytochrome P450 enzyme subfamilies, including CYP3A4 and CYP1A2, have a major role in metabolism of a range of drugs including several anti-cancer treatments. Many factors including environmental exposures, diet, diseaserelated systemic inflammation and certain genetic polymorphisms can impact the activity level of these enzymes. As a result, the net activity of each enzyme subfamily can vary widely between individuals and in the same individual over time.

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The ubiquitin proteasome system performs the covalent attachment of lysine 48-linked polyubiquitin chains to substrate proteins, thereby targeting them for degradation, while deubiquitylating enzymes (DUBs) reverse this process. This posttranslational modification regulates key features both of innate and adaptative immunity, including antigen presentation, protein homeostasis and signal transduction. Here we show that loss of one of the most highly expressed DUBs, Otub1, results in changes in murine splenic B cell subsets, leading to a significant increase in marginal zone and transitional B cells and a concomitant decrease in follicular B cells.

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Mouse is the mammalian model of choice to study human health and disease due to its size, ease of breeding and the natural occurrence of conditions mimicking human pathology. Here we design and validate multiple reaction monitoring mass spectrometry (MRM-MS) assays for quantitation of 2118 unique proteins in 20 murine tissues and organs. We provide open access to technical aspects of these assays to enable their implementation in other laboratories, and demonstrate their suitability for proteomic profiling in mice by measuring normal protein abundances in tissues from three mouse strains: C57BL/6NCrl, NOD/SCID, and BALB/cAnNCrl.

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Article Synopsis
  • * Researchers analyzed protein levels in 74 patients at three different time points after diagnosis, using a method called multiple reaction monitoring on 269 peptides, alongside routine lung function tests.
  • * The study found increases in proteins linked to lipid-related pathways over time, while those related to immune responses decreased; it also noted significant differences in protein concentrations between males and females affecting lung function.
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The rising pancreatic cancer incidence due to obesity and type 2 diabetes is closely tied to hyperinsulinemia, an independent cancer risk factor. Previous studies demonstrated reducing insulin production suppressed pancreatic intraepithelial neoplasia (PanIN) pre-cancerous lesions in Kras-mutant mice. However, the pathophysiological and molecular mechanisms remained unknown, and in particular it was unclear whether hyperinsulinemia affected PanIN precursor cells directly or indirectly.

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The post-acute sequelae of COVID-19 (PASC), also known as long COVID, is often associated with debilitating symptoms and adverse multisystem consequences. We obtain plasma samples from 117 individuals during and 6 months following their acute phase of infection to comprehensively profile and assess changes in cytokines, proteome, and metabolome. Network analysis reveals sustained inflammatory response, platelet degranulation, and cellular activation during convalescence accompanied by dysregulation in arginine biosynthesis, methionine metabolism, taurine metabolism, and tricarboxylic acid (TCA) cycle processes.

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