Amino acid analysis is a powerful bioanalytical technique for many biomedical research endeavors, including cancer, emergency medicine, nutrition and neuroscience research. In the present study, we ...present a 3 min analytical method for underivatized amino acid analysis that employs ultra high-performance liquid chromatography and high-resolution quadrupole orbitrap mass spectrometry. This method has demonstrated linearity (mM to nM range), reproducibility (intra-day <5 %, inter-day <20 %), sensitivity (low fmol) and selectivity. Here, we illustrate the rapidity and accuracy of the method through comparison with conventional liquid chromatography–mass spectrometry methods. We further demonstrate the robustness and sensitivity of this method on a diverse range of biological matrices. Using this method we were able to selectively discriminate murine pancreatic cancer cells with and without knocked down expression of hypoxia-inducible factor 1α; plasma, lymph and bronchioalveolar lavage fluid samples from control versus hemorrhaged rats; and muscle tissue samples harvested from rats subjected to both low-fat and high-fat diets. Furthermore, we were able to exploit the sensitivity of the method to detect and quantify the release of glutamate from sparsely isolated murine taste buds. Spiked in light or heavy standards (¹³C₆-arginine, ¹³C₆-lysine, ¹³C ₅ ¹⁵ N₂-glutamine) or xenometabolites (5-fluorouracil) were used to determine coefficients of variation, confirm linearity of relative quantitation in four different matrices, and overcome matrix effects for absolute quantitation. The presented method enables high-throughput analysis of low-abundance samples requiring only one percent of the material extracted from 100,000 cells, 10 µl of biological fluid, or 2 mg of muscle tissue.
The SARS-CoV-2 beta coronavirus is the etiological driver of COVID-19 disease, which is primarily characterized by shortness of breath, persistent dry cough, and fever. Because they transport oxygen, ...red blood cells (RBCs) may play a role in the severity of hypoxemia in COVID-19 patients. The present study combines state-of-the-art metabolomics, proteomics, and lipidomics approaches to investigate the impact of COVID-19 on RBCs from 23 healthy subjects and 29 molecularly diagnosed COVID-19 patients. RBCs from COVID-19 patients had increased levels of glycolytic intermediates, accompanied by oxidation and fragmentation of ankyrin, spectrin beta, and the N-terminal cytosolic domain of band 3 (AE1). Significantly altered lipid metabolism was also observed, in particular, short- and medium-chain saturated fatty acids, acyl-carnitines, and sphingolipids. Nonetheless, there were no alterations of clinical hematological parameters, such as RBC count, hematocrit, or mean corpuscular hemoglobin concentration, with only minor increases in mean corpuscular volume. Taken together, these results suggest a significant impact of SARS-CoV-2 infection on RBC structural membrane homeostasis at the protein and lipid levels. Increases in RBC glycolytic metabolites are consistent with a theoretically improved capacity of hemoglobin to off-load oxygen as a function of allosteric modulation by high-energy phosphate compounds, perhaps to counteract COVID-19-induced hypoxia. Conversely, because the N-terminus of AE1 stabilizes deoxyhemoglobin and finely tunes oxygen off-loading and metabolic rewiring toward the hexose monophosphate shunt, RBCs from COVID-19 patients may be less capable of responding to environmental variations in hemoglobin oxygen saturation/oxidant stress when traveling from the lungs to peripheral capillaries and vice versa.
The molecular mechanisms of exon definition and back-splicing are fundamental unanswered questions in pre-mRNA splicing. Here we report cryo-electron microscopy structures of the yeast spliceosomal E ...complex assembled on introns, providing a view of the earliest event in the splicing cycle that commits pre-mRNAs to splicing. The E complex architecture suggests that the same spliceosome can assemble across an exon, and that it either remodels to span an intron for canonical linear splicing (typically on short exons) or catalyses back-splicing to generate circular RNA (on long exons). The model is supported by our experiments, which show that an E complex assembled on the middle exon of yeast EFM5 or HMRA1 can be chased into circular RNA when the exon is sufficiently long. This simple model unifies intron definition, exon definition, and back-splicing through the same spliceosome in all eukaryotes and should inspire experiments in many other systems to understand the mechanism and regulation of these processes.
Metabolomics has emerged in the past decade as a highly attractive and impactful technique for phenotype-level profiling in diverse biological applications. Most recently, the dual developments of ...high-throughput analytical techniques along with dramatically increased sensitivity of high-resolution mass spectrometers have enabled the routine analysis of hundreds of unique samples per day. We have previously reported a robust 3 min isocratic metabolomics platform for the quantification of amino acids and the key pathways of central carbon and nitrogen metabolism. Building on this work, we describe here a 5 min reverse phase gradient followed by global, untargeted profiling of the hydrophilic metabolome. In addition to observing those metabolites measured in the 3 min run, the use of the longer gradient run here also allows for coverage of less polar compounds such as fatty acids and acylcarnitines, both key players in mitochondrial and lipid metabolism, without a significant sacrifice in throughput.
During the last 20 years a deeper understanding of the lymphatic circulatory system, lymph formation and composition has emerged. This review will examine the current knowledge on the organization of ...the lymphatic vascular tree, the formation of lymph from the extracellular fluid, lymph circulation and the lymph proteomic composition during physiological and pathological conditions. Formation of the lymph fluid is dependent on pressure gradients in the capillary beds and the composition of the endothelial cell glycocalyx, which acts as a molecular sieve. Fluid propulsion toward the draining node is dependent on the intrinsic pumping mechanism of the lymphangions and their unidirectional valves. The lymph 'omics' composition is dependent on the ultrafiltration of plasma proteins as well as proteins and molecules derived from the metabolic and catabolic activities of each parenchymal organ from which the lymph drains. Altogether, these new insights have brought about a new awareness of the importance of the lymphatic system in human physiology and pathology.
Human genetic studies have established a link between a class of centrosome proteins and microcephaly. Current studies of microcephaly focus on defective centrosome/spindle orientation. Mutations in ...WDR62 are associated with microcephaly and other cortical abnormalities in humans. Here we create a mouse model of Wdr62 deficiency and find that the mice exhibit reduced brain size due to decreased neural progenitor cells (NPCs). Wdr62 depleted cells show spindle instability, spindle assembly checkpoint (SAC) activation, mitotic arrest and cell death. Mechanistically, Wdr62 associates and genetically interacts with Aurora A to regulate spindle formation, mitotic progression and brain size. Our results suggest that Wdr62 interacts with Aurora A to control mitotic progression, and loss of these interactions leads to mitotic delay and cell death of NPCs, which could be a potential cause of human microcephaly.
Acute myeloid leukemia (AML) is a hematologic malignancy characterized by the accumulation of immature myeloid precursor cells. AML is poorly responsive to conventional chemotherapy and a diagnosis ...of AML is usually fatal. More effective and less toxic forms of therapy are desperately needed. AML cells are known to be highly dependent on the amino acid glutamine for their survival. These studies were directed at determining the effects of glutaminase inhibition on metabolism in AML and identifying general weaknesses that can be exploited therapeutically.
AML cancer cell lines, primary AML cells, and mouse models of AML and acute lymphoblastic leukemia (ALL) were utilized.
We show that blocking glutamine metabolism through the use of a glutaminase inhibitor (CB-839) significantly impairs antioxidant glutathione production in multiple types of AML, resulting in accretion of mitochondrial reactive oxygen species (mitoROS) and apoptotic cell death. Moreover, glutaminase inhibition makes AML cells susceptible to adjuvant drugs that further perturb mitochondrial redox state, such as arsenic trioxide (ATO) and homoharringtonine (HHT). Indeed, the combination of ATO or HHT with CB-839 exacerbates mitoROS and apoptosis, and leads to more complete cell death in AML cell lines, primary AML patient samples, and
using mouse models of AML. In addition, these redox-targeted combination therapies are effective in eradicating ALL cells
and
.
Targeting glutamine metabolism in combination with drugs that perturb mitochondrial redox state represents an effective and potentially widely applicable therapeutic strategy for treating multiple types of leukemia.
Metabolomics in transfusion medicine Nemkov, Travis; Hansen, Kirk C.; Dumont, Larry J. ...
Transfusion (Philadelphia, Pa.),
April 2016, Letnik:
56, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Biochemical investigations on the regulatory mechanisms of red blood cell (RBC) and platelet (PLT) metabolism have fostered a century of advances in the field of transfusion medicine. Owing to these ...advances, storage of RBCs and PLT concentrates has become a lifesaving practice in clinical and military settings. There, however, remains room for improvement, especially with regard to the introduction of novel storage and/or rejuvenation solutions, alternative cell processing strategies (e.g., pathogen inactivation technologies), and quality testing (e.g., evaluation of novel containers with alternative plasticizers). Recent advancements in mass spectrometry–based metabolomics and systems biology, the bioinformatics integration of omics data, promise to speed up the design and testing of innovative storage strategies developed to improve the quality, safety, and effectiveness of blood products.
Here we review the currently available metabolomics technologies and briefly describe the routine workflow for transfusion medicine–relevant studies. The goal is to provide transfusion medicine experts with adequate tools to navigate through the otherwise overwhelming amount of metabolomics data burgeoning in the field during the past few years.
Descriptive metabolomics data have represented the first step omics researchers have taken into the field of transfusion medicine. However, to up the ante, clinical and omics experts will need to merge their expertise to investigate correlative and mechanistic relationships among metabolic variables and transfusion‐relevant variables, such as 24‐hour in vivo recovery for transfused RBCs. Integration with systems biology models will potentially allow for in silico prediction of metabolic phenotypes, thus streamlining the design and testing of alternative storage strategies and/or solutions.
Acetylation within the globular core domain of histone H3 on lysine 56 (H3K56) has recently been shown to have a critical role in packaging DNA into chromatin following DNA replication and repair in ...budding yeast. However, the function or occurrence of this specific histone mark has not been studied in multicellular eukaryotes, mainly because the Rtt109 enzyme that is known to mediate acetylation of H3K56 (H3K56ac) is fungal-specific. Here we demonstrate that the histone acetyl transferase CBP (also known as Nejire) in flies and CBP and p300 (Ep300) in humans acetylate H3K56, whereas Drosophila Sir2 and human SIRT1 and SIRT2 deacetylate H3K56ac. The histone chaperones ASF1A in humans and Asf1 in Drosophila are required for acetylation of H3K56 in vivo, whereas the histone chaperone CAF-1 (chromatin assembly factor 1) in humans and Caf1 in Drosophila are required for the incorporation of histones bearing this mark into chromatin. We show that, in response to DNA damage, histones bearing acetylated K56 are assembled into chromatin in Drosophila and human cells, forming foci that colocalize with sites of DNA repair. Furthermore, acetylation of H3K56 is increased in multiple types of cancer, correlating with increased levels of ASF1A in these tumours. Our identification of multiple proteins regulating the levels of H3K56 acetylation in metazoans will allow future studies of this critical and unique histone modification that couples chromatin assembly to DNA synthesis, cell proliferation and cancer.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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