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Amino Acids May 2023Adiposity is an important determinant of blood metabolites, but little is known about the variations of blood amino acids according to general and central adiposity...
Adiposity is an important determinant of blood metabolites, but little is known about the variations of blood amino acids according to general and central adiposity status among Chinese population. This study included 187 females and 322 males who were cancer-free subjects randomly selected from two cohorts in Shanghai, China. Participants' plasma concentrations of amino acids were measured by ultra-performance liquid chromatography coupled to tandem mass spectrometry. Linear regression models were used to examine the cross-sectional correlations between general and central adiposity and amino acid levels. A total of 35 amino acids in plasma were measured in this study. In females, alanine, aspartic acid and pyroglutamic acid were positively correlated with general adiposity. In males, glutamic acid, aspartic acid, valine and pyroglutamic acid showed positive correlations, and glutamine, serine and glycine showed negative correlations with both general and central adiposity; phenylalanine, isoleucine and leucine were positively correlated and N-phenylacetylglutamine was negatively correlated with general adiposity; asparagine was negatively correlated with central adiposity. In summary, general adiposity and central adiposity were correlated with the concentrations of specific plasma amino acids among cancer-free female and male adults in China. Adiposity-metabolite characteristics and relationships should be considered when studying blood biomarkers for adiposity-related health outcomes.
Topics: Adult; Female; Humans; Male; Adiposity; Amino Acids; China; East Asian People; Pyrrolidonecarboxylic Acid
PubMed: 36881189
DOI: 10.1007/s00726-023-03258-5 -
Anticancer Research Mar 2023Monocarboxylate transporters (MCTs) transport short-chain monocarboxylates, such as lactate, and have been reported to be related to poor prognosis in breast cancer. Our...
BACKGROUND/AIM
Monocarboxylate transporters (MCTs) transport short-chain monocarboxylates, such as lactate, and have been reported to be related to poor prognosis in breast cancer. Our previous studies showed that a high glucose state altered MCT expression and changed the sensitivity of the tamoxifen active metabolite 4-hydroxytamoxifen (4-OHT) via hypoxia-inducible factor-1α (HIF-1α) protein expression. We hypothesized that MCT inhibitors affect 4-OHT-induced cytotoxicity under normal glucose conditions by decreasing HIF-1α protein expression. To test this hypothesis, we evaluated the combined effect of MCT inhibitor and 4-OHT using the estrogen receptor (ER)-positive breast cancer cell line MCF-7, under normal glucose conditions.
MATERIALS AND METHODS
Expression of MCTs and oxidative stress markers was evaluated by real-time PCR. Cell viability was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Reactive oxygen species (ROS) were measured using the cell permeability probe 2',7'-dichlorodihydrofluorescein diacetate.
RESULTS
MCT1 expression increased under normal glucose conditions. The MCT1 substrate/inhibitor, 5-oxoproline (5-OP), enhanced 4-OHT-induced cytotoxicity. Bindarit, a selective MCT4 inhibitor, decreased 4-OHT sensitivity, similar to results of our previous study under high glucose conditions. In contrast, the combination of 5-OP and 4-OHT decreased ATP levels compared with that by 4-OHT alone in MCF-7 cells. Furthermore, 5-OP significantly increased the ROS production induced by 4-OHT.
CONCLUSION
5-OP enhances 4-OHT-induced cytotoxicity in ER-positive breast cancer cells under normal glucose conditions.
Topics: Humans; Female; Breast Neoplasms; Pyrrolidonecarboxylic Acid; MCF-7 Cells; Reactive Oxygen Species; Tamoxifen; Oxidative Stress; Glucose
PubMed: 36854517
DOI: 10.21873/anticanres.16256 -
European Journal of Internal Medicine Apr 2023
Topics: Humans; Alcoholic Intoxication; Alcoholism; Pyrrolidonecarboxylic Acid; Pyridoxine; Drug Combinations
PubMed: 36797119
DOI: 10.1016/j.ejim.2023.02.012 -
Analytical Chemistry Feb 2023Pertuzumab is a monoclonal antibody used for the treatment of HER2-positive breast cancer in combination with trastuzumab. Charge variants of trastuzumab have been...
Pertuzumab is a monoclonal antibody used for the treatment of HER2-positive breast cancer in combination with trastuzumab. Charge variants of trastuzumab have been extensively described in the literature; however, little is known about the charge heterogeneity of pertuzumab. Here, changes in the ion-exchange profile of pertuzumab were evaluated by pH gradient cation-exchange chromatography after stressing it for up to 3 weeks at physiological and elevated pH and 37 °C. Isolated charge variants arising under stress conditions were characterized by peptide mapping. The results of peptide mapping showed that deamidation in the Fc domain and N-terminal pyroglutamate formation in the heavy chain are the main contributors to charge heterogeneity. The heavy chain CDR2, which is the only CDR containing asparagine residues, was quite resistant to deamidation under stress conditions according to peptide mapping results. Using surface plasmon resonance, it was shown that the affinity of pertuzumab for the HER2 target receptor does not change under stress conditions. Peptide mapping analysis of clinical samples showed an average of 2-3% deamidation in the heavy chain CDR2, 20-25% deamidation in the Fc domain, and 10-15% N-terminal pyroglutamate formation in the heavy chain. These findings suggest that stress studies are able to predict modifications.
Topics: Humans; Female; Complementarity Determining Regions; Pyrrolidonecarboxylic Acid; Antibodies, Monoclonal, Humanized; Trastuzumab; Breast Neoplasms; Receptor, ErbB-2
PubMed: 36795375
DOI: 10.1021/acs.analchem.2c03275 -
Frontiers in Immunology 2022Noninvasive methods for the early identify diagnosis of prostatitis, benign prostatic hyperplasia (BPH), and prostate cancer (PCa) are current clinical challenges.
BACKGROUND
Noninvasive methods for the early identify diagnosis of prostatitis, benign prostatic hyperplasia (BPH), and prostate cancer (PCa) are current clinical challenges.
METHODS
The serum metabolites of 20 healthy individuals and patients with prostatitis, BPH, or PCa were identified using untargeted liquid chromatography-mass spectrometry (LC-MS). In addition, targeted LC-MS was used to verify the organic acid metabolites in the serum of a validation cohort.
RESULTS
Organic acid metabolites had good sensitivity and specificity in differentiating prostatitis, BPH, and PCa. Three diagnostic models identified patients with PROSTATITIS: phenyllactic acid (area under the curve [AUC]=0.773), pyroglutamic acid (AUC=0.725), and pantothenic acid (AUC=0.721). Three diagnostic models identified BPH: citric acid (AUC=0.859), malic acid (AUC=0.820), and D-glucuronic acid (AUC=0.810). Four diagnostic models identified PCa: 3-hydroxy-3-methylglutaric acid (AUC=0.804), citric acid (AUC=0.918), malic acid (AUC=0.862), and phenyllactic acid (AUC=0.713). Two diagnostic models distinguished BPH from PCa: phenyllactic acid (AUC=0.769) and pyroglutamic acid (AUC=0.761). Three diagnostic models distinguished benign BPH from PROSTATITIS: citric acid (AUC=0.842), ethylmalonic acid (AUC=0.814), and hippuric acid (AUC=0.733). Six diagnostic models distinguished BPH from prostatitis: citric acid (AUC=0.926), pyroglutamic acid (AUC=0.864), phenyllactic acid (AUC=0.850), ethylmalonic acid (AUC=0.843), 3-hydroxy-3-methylglutaric acid (AUC=0.817), and hippuric acid (AUC=0.791). Three diagnostic models distinguished PCa patients with PROSTATITISA < 4.0 ng/mL from those with PSA > 4.0 ng/mL: 5-hydromethyl-2-furoic acid (AUC=0.749), ethylmalonic acid (AUC=0.750), and pyroglutamic acid (AUC=0.929). Conclusions: These results suggest that serum organic acid metabolites can be used as biomarkers to differentiate prostatitis, BPH, and PCa.
Topics: Male; Humans; Prostatic Hyperplasia; Prostatitis; Prostate-Specific Antigen; Meglutol; Pyrrolidonecarboxylic Acid; Prostatic Neoplasms; Biomarkers
PubMed: 36685547
DOI: 10.3389/fimmu.2022.998447 -
Journal of Microbiology and... Feb 2023Taste is classified into five types, each of which has evolved to play its respective role in mammalian survival. Sour taste is one of the important ways to judge...
Taste is classified into five types, each of which has evolved to play its respective role in mammalian survival. Sour taste is one of the important ways to judge whether food has gone bad, and the sour taste receptor (PKD2L1) is the gene behind it. Here, we investigated whether L-pyroglutamic acid interacts with sour taste receptors through electrophysiology and mutation experiments using oocytes. R299 of hPKD2L1 was revealed to be involved in L-pyroglutamic acid binding in a concentration-dependent manner. As a result, it is possible to objectify the change in signal intensity according to the concentration of L-pyroglutamic acid, an active ingredient involved in the taste of kimchi, at the molecular level. Since the taste of other ingredients can also be measured with the method used in this experiment, it is expected that an objective database of taste can be created.
Topics: Animals; Humans; Calcium Channels; Pyrrolidonecarboxylic Acid; Receptors, Cell Surface; Taste; Taste Buds; Xenopus laevis
PubMed: 36655284
DOI: 10.4014/jmb.2212.12007 -
Scientific Reports Jan 2023Pyroglutamate amyloid-β (Aβ) is an N-terminally truncated and pyroglutamate-modified Aβ peptide retaining highly hydrophobic, amyloidogenic, and neurotoxic...
Pyroglutamate amyloid-β (Aβ) is an N-terminally truncated and pyroglutamate-modified Aβ peptide retaining highly hydrophobic, amyloidogenic, and neurotoxic properties. In Alzheimer's disease (AD) patients, Aβ peptides accumulate into oligomers and induce cellular toxicity and synaptic dysfunction. Aβ aggregates further seed the formation of amyloid plaques, which are the pathological hallmarks of AD. Given that Aβ peptides play critical roles in the development of neurodegeneration, a reliable and reproducible synthetic access to these peptides may support pathological and medicinal studies of AD. Here, we synthesized Aβ peptides through the microwave-assisted solid-phase peptide synthesis (SPPS). Utilizing thioflavin T fluorescence assay and dot blotting analysis with anti-amyloid oligomer antibody, the amyloidogenic activity of synthesized Aβ peptides was confirmed. We further observed the cytotoxicity of Aβ aggregates in cell viability test. To examine the cognitive deficits induced by synthetic Aβ peptides, Aβ oligomers were intracerebroventricularly injected into imprinting control region mice and Y-maze and Morris water maze tests were performed. We found that Aβ aggregates altered the expression level of postsynaptic density protein 95 in cortical lysates. Collectively, we produced Aβ peptides in the microwave-assisted SPPS and evaluated the amyloidogenic and pathological function of the synthesized peptides.
Topics: Animals; Mice; Pyrrolidonecarboxylic Acid; Solid-Phase Synthesis Techniques; Peptide Fragments; Amyloid beta-Peptides; Alzheimer Disease
PubMed: 36627316
DOI: 10.1038/s41598-022-26616-x -
Protein Expression and Purification Apr 2023Neurotensin (NT) is a 13-residue endogenous peptide found in mammals, with neurotransmission and hormonal roles in the central nervous system and gastrointestinal tract,...
Neurotensin (NT) is a 13-residue endogenous peptide found in mammals, with neurotransmission and hormonal roles in the central nervous system and gastrointestinal tract, respectively. The first residue of NT is a pyroglutamate (pGlu) that makes the expression and purification of large amounts of NT with native modification challenging. Here, we describe a simple and efficient procedure for expression and purification of large amounts of NT based on using the small ubiquitin-like modifier (SUMO) as a fusion partner and subsequent enzymatic conversion of the N-terminal glutamine to pGlu. Yields of 13 mg/L and 8 mg/L of pure peptide were obtained from expression in rich and minimal media, respectively. The method is adaptable to expression and purification of proteins and peptides with pGlu modification in a wide range of eukaryotic and prokaryotic expression hosts.
Topics: Animals; Neurotensin; Pyrrolidonecarboxylic Acid; Peptides; Glutamine; Mammals
PubMed: 36574939
DOI: 10.1016/j.pep.2022.106227 -
Pharmacological Reports : PR Feb 2023Neurosteroids are investigated as effective antidotes for the poisoning induced by tetramethylenedisulfotetramine (TMDT) as well as treatments for epileptic spasms...
Novel neurosteroid pregnanolone pyroglutamate suppresses neurotoxicity syndrome induced by tetramethylenedisulfotetramine but is ineffective in a rodent model of infantile spasms.
BACKGROUND
Neurosteroids are investigated as effective antidotes for the poisoning induced by tetramethylenedisulfotetramine (TMDT) as well as treatments for epileptic spasms during infancy. Both these conditions are quite resistant to pharmacotherapy; thus, a search for new treatments is warranted.
METHODS
In this study, we determined the efficacy of two novel neurosteroids, pregnanolone glutamate (PAG) and pregnanolone pyroglutamate (PPG), and tested these drugs in doses of 1-10 mg/kg (ip) against the TMDT syndrome and in our rodent model of infantile spasms.
RESULTS
Only PPG in doses 5 and 10 mg/kg suppressed the severity of the TMDT syndrome and TMDT-induced lethality, while the 1 mg/kg dose was without an effect. Interestingly, the 1 mg/kg dose of PPG in combination with 1 mg/kg of diazepam was also effective against TMDT poisoning. Neither PAG nor PPG were effective against experimental spasms in the N-methyl-D-aspartate (NMDA)-triggered model of infantile spasms.
CONCLUSIONS
While evidence suggests that PAG can act through multiple actions which include allosteric inhibition of NMDA-induced and glycine receptor-evoked currents as well as augmentation of ɣ-aminobutyric acid subtype A (GABAA) receptor-induced currents, the agent appears to neither have the appropriate mechanistic signature for activity in the infantile spasm model, nor the adequate potency, relative to PPG, for ameliorating the TMDT syndrome. The full mechanisms of action of PPG, which may become a potent TMDT antidote either alone or in combination with diazepam are yet unknown and thus require further investigation.
Topics: Animals; Spasms, Infantile; Pregnanolone; Pyrrolidonecarboxylic Acid; Neurosteroids; N-Methylaspartate; Rodentia; Diazepam; Neurotoxicity Syndromes; Glutamic Acid; Spasm
PubMed: 36422805
DOI: 10.1007/s43440-022-00437-1 -
Journal of Assisted Reproduction and... Dec 2022Polycystic ovary syndrome is a complex heterogeneous endocrine disorder associated with established metabolic abnormalities and is a common cause of infertility in...
PURPOSE
Polycystic ovary syndrome is a complex heterogeneous endocrine disorder associated with established metabolic abnormalities and is a common cause of infertility in females. Glutathione metabolism in the cumulus cells (CCs) of women with PCOS may be correlated to the quality of oocytes for infertility treatment; therefore, we used a metabolomics approach to examine changes in CCs from women with PCOS and oocyte quality.
METHODS
Among 135 women undergoing fertility treatment in the present study, there were 43 women with PCOS and 92 without. CCs were collected from the two groups and levels of pyroglutamic acid were measured using LC-MS/MS followed by qPCR and Western blot analysis to examine genes and proteins involved in pyroglutamic acid metabolism related to glutathione synthesis.
RESULTS
Women with PCOS showed increased levels of L-pyroglutamic acid, L-glutamate, and L-phenylalanine and decreased levels of Cys-Gly and N-acetyl-L-methionine. Gene expression of OPLAH, involved in pyroglutamic synthesis, was significantly increased in women with PCOS compared with those without. Gene expression of GSS was significantly decreased in women with PCOS and synthesis of glutathione synthetase protein was decreased. Expression of nuclear factor erythroid 2-related factor 2, involved in resistance to oxidative stress, was significantly increased in women with PCOS.
CONCLUSIONS
CCs of women with PCOS showed high concentrations of pyroglutamic acid and reduced glutathione synthesis, which causes oxidative stress in CCs, suggesting that decreased glutathione synthesis due to high levels of pyroglutamic acid in CCs may be related to the quality of oocytes in women with PCOS.
Topics: Humans; Female; Polycystic Ovary Syndrome; Cumulus Cells; Pyrrolidonecarboxylic Acid; Chromatography, Liquid; Tandem Mass Spectrometry; Oocytes; Infertility; Glutathione
PubMed: 36322230
DOI: 10.1007/s10815-022-02647-1