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Acta Neuropathologica Communications Jan 2018Alzheimer's disease (AD) is the most common cause of dementia among older adults. Accumulation of amyloid-β (Aβ) in the brain is considered central in AD pathogenesis...
Alzheimer's disease (AD) is the most common cause of dementia among older adults. Accumulation of amyloid-β (Aβ) in the brain is considered central in AD pathogenesis and its understanding crucial for developing new diagnostic and therapeutic approaches. Recent literature suggests that ageing may induce post translational modifications in Aβ, in the form of spontaneous amino acid modifications, which enhance its pathogenic properties, contributing to its aggregation.In this study, we have investigated whether the isoaspartate (IsoD-Aβ) and pyroglutamate (pE3-Aβ) modified forms of Aβ are significantly associated with AD pathology or represent markers of ageing. Cerebral neocortex of 27 AD cases, 32 old controls (OC) and 11 young controls (YC) was immunostained for pE3-Aβ and IsoD-Aβ, quantified as protein load and correlated with other Aβ forms and p-TAU. IsoD-Aβ and pE3-Aβ were detected at low levels in non-demented controls, and significantly increased in AD (p ≤ 0.001), with a characteristic deposition of IsoD-Aβ in blood vessel walls and pE3-Aβ within neurons. Both AD and OC showed positive associations between IsoD-Aβ and Aβ (p = 0.003 in AD and p = 0.001 in OC) and between IsoD-Aβ and pE3-Aβ (p = 0.001 in AD and OC). This last association was the only significant pE3-Aβ correlation identified in AD, whereas in the control cohorts pE3-Aβ also correlated with Aβ and AβPP (p = 0.001 in OC and p = 0.010 in YC).Our analyses suggest that IsoD-Aβ accumulation starts with ageing; whereas pE3-Aβ deposition is more closely linked to AD. Our findings support the importance of age-related modifications of Aβ in AD pathogenesis.
Topics: Adult; Aged; Aged, 80 and over; Aging; Alzheimer Disease; Amyloid beta-Peptides; Brain; Female; Humans; Isoaspartic Acid; Male; Middle Aged; Neocortex; Protein Processing, Post-Translational; Pyrrolidonecarboxylic Acid; Statistics, Nonparametric; Young Adult
PubMed: 29298722
DOI: 10.1186/s40478-017-0505-x -
Scientific Reports Sep 20225-Oxoproline (5OP) is a poorly researched ubiquitous natural amino acid found in all life forms. We have previously shown that Salmonella enterica serovar Typhimurium...
5-Oxoproline (5OP) is a poorly researched ubiquitous natural amino acid found in all life forms. We have previously shown that Salmonella enterica serovar Typhimurium (Salmonella) responds to 5OP exposure by reducing cyclic-di-GMP levels, and resultant cellulose dependent cellular aggregation in a YfeA and BcsA dependent manner. To understand if 5OP was specifically sensed by Salmonella we compared the interaction of Salmonella with 5OP to that of the chemically similar and biologically relevant molecule, L-proline. We show that L-proline but not 5OP can be utilized by Salmonella as a nutrient source. We also show that 5OP but not L-proline regulates cellulose dependent cellular aggregation. These results imply that 5OP is utilized by Salmonella as a specific signal. However, L-proline is a 5OP aggregation inhibitor implying that while it cannot activate the aggregation pathway by itself, it can inhibit 5OP dependent activation. We then show that in a L-proline transporter knockout mutant L-proline competition remain unaffected, implying sensing of 5OP is extracellular. Last, we identify a transcriptional effect of 5OP exposure, upregulation of the mgtCBR operon, known to be activated during host invasion. While mgtCBR is known to be regulated by both low pH and L-proline starvation, we show that 5OP regulation of mgtCBR is indirect through changes in pH and is not dependent on the 5OP chemical structure similarity to L-proline. We also show this response to be PhoPQ dependent. We further show that the aggregation response is independent of pH modulation, PhoPQ and MgtC and that the mgtCBR transcriptional response is independent of YfeA and BcsA. Thus, the two responses are mediated through two independent signaling pathways. To conclude, we show Salmonella responds to 5OP specifically to regulate aggregation and not specifically to regulate gene expression. When and where in the Salmonella life cycle does 5OP sensing takes place remains an open question. Furthermore, because 5OP inhibits c-di-GMP through the activation of an external sensor, and does not require an internalization step like many studied biofilm inhibitors, 5OP or derivatives might be developed into useful biofilm inhibitors.
Topics: Bacterial Proteins; Cellulose; Gene Expression Regulation, Bacterial; Proline; Pyrrolidonecarboxylic Acid; Salmonella typhimurium; Serogroup
PubMed: 36153368
DOI: 10.1038/s41598-022-20407-0 -
Insect Biochemistry and Molecular... Jun 2021Lipid homeostasis is essential for insects to maintain phospholipid (PL)-based membrane integrity and to provide on-demand energy supply throughout life. Triacylglycerol...
Lipid homeostasis is essential for insects to maintain phospholipid (PL)-based membrane integrity and to provide on-demand energy supply throughout life. Triacylglycerol (TAG) is the major lipid class used for energy production and is stored in lipid droplets, the universal cellular fat storage organelles. Accumulation and mobilization of TAG are strictly regulated since excessive accumulation of TAG leads to obesity and has been correlated with adverse effects on health- and lifespan across phyla. Little is known, however, about when during adult life and why excessive storage lipid accumulation restricts lifespan. We here used genetically obese Drosophila mutant males, which were all shown to be short-lived compared to control males and applied single fly mass spectrometry-based lipidomics to profile TAG, diacylglycerol and major membrane lipid signatures throughout adult fly life from eclosion to death. Our comparative approach revealed distinct phases of lipidome remodeling throughout aging. Quantitative and qualitative compositional changes of TAG and PL species, which are characterized by the length and saturation of their constituent fatty acids, were pronounced during young adult life. In contrast, lipid signatures of adult and senescent flies were remarkably stable. Genetically obese flies displayed both quantitative and qualitative changes in TAG species composition, while PL signatures were almost unaltered compared to normal flies at all ages. Collectively, this suggests a tight control of membrane composition throughout lifetime largely uncoupled from storage lipid metabolism. Finally, we present first evidence for a characteristic lipid signature of moribund flies, likely generated by a rapid and selective storage lipid depletion close to death. Of note, the analytical power to monitor lipid species profiles combined with high sensitivity of this single fly lipidomics approach is universally applicable to address developmental or behavioral lipid signature modulations of importance for insect life.
Topics: Aging; Animals; Drosophila Proteins; Drosophila melanogaster; Fatty Acids; Insect Hormones; Lipase; Lipid Metabolism; Lipidomics; Longevity; Male; Obesity; Oligopeptides; Pyrrolidonecarboxylic Acid; Triglycerides
PubMed: 33221388
DOI: 10.1016/j.ibmb.2020.103498 -
Scientific Reports Mar 2017-Amino acids are enantiomers of L-amino acids and have recently been recognized as biomarkers and bioactive substances in mammals, including humans. In the present...
-Amino acids are enantiomers of L-amino acids and have recently been recognized as biomarkers and bioactive substances in mammals, including humans. In the present study, we investigated functions of the novel mammalian mitochondrial protein 9030617O03Rik and showed decreased expression under conditions of heart failure. Genomic sequence analyses showed partial homology with a bacterial aspartate/glutamate/hydantoin racemase. Subsequent determinations of all free amino acid concentrations in 9030617O03Rik-deficient mice showed high accumulations of D-glutamate in heart tissues. This is the first time that a significant amount of D-glutamate was detected in mammalian tissue. Further analysis of D-glutamate metabolism indicated that 9030617O03Rik is a D-glutamate cyclase that converts D-glutamate to 5-oxo-D-proline. Hence, this protein is the first identified enzyme responsible for mammalian D-glutamate metabolism, as confirmed in cloning analyses. These findings suggest that D-glutamate and 5-oxo-D-proline have bioactivities in mammals through the metabolism by D-glutamate cyclase.
Topics: Animals; Glutamic Acid; Hydro-Lyases; Mice; Mice, Knockout; Mitochondria, Heart; Mitochondrial Proteins; Pyrrolidonecarboxylic Acid
PubMed: 28266638
DOI: 10.1038/srep43911 -
Journal of Chromatography. B,... Nov 2018The aim of this study was to develop a method to detect serum organic acid profiles in patients with isolated post-challenge diabetes (IPD) and to compare the...
The aim of this study was to develop a method to detect serum organic acid profiles in patients with isolated post-challenge diabetes (IPD) and to compare the metabolites between IPD patients, type 2 diabetes mellitus (T2DM) and healthy controls. We developed a gas chromatography-mass spectrometry method to detect serum organic acids and validated it using serum from 40 patients with IPD, 47 with newly diagnosed T2DM, and 48 healthy controls. We then analyzed the organic acid profiles by multivariate analysis to identify potential metabolites. This method allowed the fast and accurate measurement of 27 organic acids in serum. Serum organic acid profiles differed significantly among IPD patients, T2DM patients, and healthy controls. IPD samples had significantly higher concentrations of α‑hydroxybutyrate and β‑hydroxybutyrate (P < 0.05) and lower pyroglutamic acid concentration (P < 0.05) compared with the healthy controls, and the area under the curve for the combination of α‑hydroxybutyrate and pyroglutamic acid was 0.863 for the IPD group. These results provide useful information regarding the changes in organic acid metabolism associated with IPD. Measurement of these metabolites in fasting serum from IPD patients may provide useful diagnostic and/or prognostic biomarkers, as well as helpful markers for the therapeutic monitoring of IPD patients.
Topics: Biomarkers; Carboxylic Acids; Diabetes Mellitus, Type 2; Fasting; Female; Humans; Hydroxybutyrates; Limit of Detection; Linear Models; Male; Metabolome; Middle Aged; Pyrrolidonecarboxylic Acid; Reproducibility of Results
PubMed: 30267980
DOI: 10.1016/j.jchromb.2018.09.004 -
Expert Review of Respiratory Medicine Jun 2020: The prevalence of chronic inflammatory airway diseases is rising. Their treatment with corticosteroids increases infection risk, while overuse of antimicrobial agents... (Review)
Review
: The prevalence of chronic inflammatory airway diseases is rising. Their treatment with corticosteroids increases infection risk, while overuse of antimicrobial agents may increase morbidity and antimicrobial resistance. Nonspecific immunomodulatory compounds alter immune responses to both infectious and atopic challenges. These compounds may offer an alternative approach for symptom reduction and prophylaxis against both infections and exacerbations in chronic inflammatory airway disease.: We assessed the available data on the efficacy of nonspecific immunomodulators including bacterial lysates, synthetic compounds, and vaccines in chronic rhinosinusitis (CRS); allergic and non-allergic rhinitis; chronic obstructive pulmonary disease (COPD), and asthma. A search of PubMed was carried out using the 'Clinical Trials' filter for each condition and immunomodulatory product detailed below, where available, data from meta-analyses were reported.: Pre-clinical data has revealed a coherent mechanistic path of action for oral immunomodulators on the respiratory immune system, principally via the gut-lung immune axis. In patients with asthma, allergic rhinitis, CRS, and COPD immunomodulatory therapy reduces symptoms, exacerbations, hospitalizations, and drug consumption. However, data are heterogeneous, and study quality remains limited. A lack of high-quality recent trials remains the major unmet research need in the field.
Topics: Asthma; Cell Extracts; Chronic Disease; Humans; Immunization; Immunologic Factors; Immunomodulation; Inflammation; Probiotics; Pulmonary Disease, Chronic Obstructive; Pyrrolidonecarboxylic Acid; Respiratory System; Respiratory Tract Diseases; Rhinitis; Sinusitis; Thiazolidines
PubMed: 32250709
DOI: 10.1080/17476348.2020.1744436 -
Bioorganic & Medicinal Chemistry Jan 2017Stimulation of the NTS2 neurotensin receptor causes antipsychotic effects and leads to a promotion of the μ-opioid-independent antinociception, which is important in...
Stimulation of the NTS2 neurotensin receptor causes antipsychotic effects and leads to a promotion of the μ-opioid-independent antinociception, which is important in the modulation of tonic pain sensitivity. We report the synthesis and properties of a small library of peptidic agonists based on the active neurotensin fragment NT(8-13). Two tetrahydrofuran amino acid derivatives were synthesized to replace Tyr in NT(8-13). Additionally, Arg, Arg, and Ile of the lead peptide were exchanged by Lys, Lys, and Gly, respectively. The new compounds showed substantial NTS2 binding affinity and up to 1000-fold selectivity over NTS1. The highest selectivity (K(NTS2): 29nM, K(NTS1): 35,000nM) was observed for the peptide analog 17R.
Topics: Animals; Binding Sites; CHO Cells; Cricetulus; Furans; HEK293 Cells; Humans; Molecular Conformation; Molecular Dynamics Simulation; Molecular Mimicry; Neurotensin; Peptide Fragments; Peptidomimetics; Pyrrolidonecarboxylic Acid; Receptors, Neurotensin
PubMed: 27842797
DOI: 10.1016/j.bmc.2016.10.039 -
Journal of Nuclear Medicine : Official... Mar 2017The purinergic receptor subtype 7 (P2X7R) represents a novel molecular target for imaging neuroinflammation via PET. GSK1482160, a potent P2X7R antagonist, has high...
The purinergic receptor subtype 7 (P2X7R) represents a novel molecular target for imaging neuroinflammation via PET. GSK1482160, a potent P2X7R antagonist, has high receptor affinity, high blood-brain barrier penetration, and the ability to be radiolabeled with C. We report the initial physical and biologic characterization of this novel ligand. C-GSK1482160 was synthesized according to published methods. Cell density studies were performed on human embryonic kidney cell lines expressing human P2X7R (HEK293-hP2X7R) and underwent Western blotting, an immunofluorescence assay, and radioimmunohistochemistry analysis using P2X7R polyclonal antibodies. Receptor density and binding potential were determined by saturation and association-disassociation kinetics, respectively. Peak immune response to lipopolysaccharide treatment in mice was determined in time course studies and analyzed via Iba1 and P2X7R Western blotting and Iba1 immunohistochemistry. Whole-animal biodistribution studies were performed on saline- or lipopolysaccharide-treated mice at 15, 30, and 60 min after radiotracer administration. Dynamic in vivo PET/CT was performed on the mice at 72 h after administration of saline, lipopolysaccharide, or lipopolysaccharide + blocking, and 2-compartment, 5-parameter tracer kinetic modeling of brain regions was performed. P2X7R changed linearly with concentrations or cell numbers. For high-specific-activity C-GSK1482160, receptor density and K were 1.15 ± 0.12 nM and 3.03 ± 0.10 pmol/mg, respectively, in HEK293-hP2X7R membranes. Association constant , dissociation constant , and binding potential (/) in HEK293-hP2X7R cells were 0.2312 ± 0.01542 min⋅nM, 0.2547 ± 0.0155 min, and 1.0277 ± 0.207, respectively. Whole-brain Iba1 expression in lipopolysaccharide-treated mice peaked by 72 h on immunohistochemistry, and Western blot analysis of P2X7R for saline- and lipopolysaccharide-treated brain sections showed a respective 1.8- and 1.7-fold increase in signal enhancement at 72 h. Biodistribution of C-GSK1482160 in saline- and lipopolysaccharide-treated mice at 72 h was statistically significant across all tissues studied. In vivo dynamic C-GSK1482160 PET/CT of mice at 72 h after administration of saline, lipopolysaccharide, or lipopolysaccharide + blocking showed a 3.2-fold increase and 97% blocking by 30 min. The total distribution volumes for multiple cortical regions and the hippocampus showed statistically significant increases and were blocked by an excess of authentic standard GSK1482160. The current study provides compelling data that support the suitability of C-GSK1482160 as a radioligand targeting P2X7R, a biomarker of neuroinflammation.
Topics: Animals; Biomarkers; Brain; Carbon Radioisotopes; Encephalitis; Humans; Inflammation Mediators; Mice; Mice, Inbred C57BL; Molecular Imaging; Positron-Emission Tomography; Pyrrolidonecarboxylic Acid; Radiopharmaceuticals; Receptors, Purinergic P2X7; Reproducibility of Results; Sensitivity and Specificity
PubMed: 27765863
DOI: 10.2967/jnumed.116.181354 -
International Immunopharmacology Feb 2019Recurrent respiratory tract infections (RRTIs) remain a great challenge to pediatricians, because they can increase the risk of various complications and there is no... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
Recurrent respiratory tract infections (RRTIs) remain a great challenge to pediatricians, because they can increase the risk of various complications and there is no confirmed effective treatment. In the present study, we aimed to assess the effectiveness and safety of pidotimod (PDT), an immunostimulant, in treatment of RRTIs in children aged 14 years and under.
METHODS
PubMed, EMBASE, Web of Science, Cochrane Library, ClinicalTrials.gov, CBM and CNKI were searched from their inception up to February 2018. All randomized controlled trials (RCTs) using PDT with various treatment durations and enrolling participants <14 years of age were included in the present review. The interventions were PDT plus conventional treatment (e.g. anti-bacterial and antiviral therapy) or PDT alone versus the conventional treatment plus placebo or conventional treatment alone.
RESULTS
A total of 29 RCTs consisting of 4344 pediatric patients were included in this meta-analysis. Ten RCTs were published from Italy, Russia or Greece, and 19 RCTs were published by Chinese groups. However, appropriate randomization methods were only used in 15 trials. Only one study had explicit allocation concealment. Since only eight RCTs were double-blind and placebo controlled, the evidence was not assessed as high quality. The meta-analysis indicates that treatment with PDT resulted in a significant increase in the proportion of participants who had lower RTIs (RR 1.59; 95% CI 1.45-1.74, p < 0.00001) compared with the conventional treatment. PDT could significantly decrease the duration of cough and fever. The number of patients in using antibiotics was also remarkably decreased in the PDT treatment group. Moreover, PDT administration improved the levels of serum immunoglobulin (IgG, IgA, or IgM) and T-lymphocyte subtypes (CD3+, CD4+). Besides, PDT administration did not increase the risk of adverse events of any cause (RR = 1.05, 95% CI 0.72-1.54, p = 0.80).
CONCLUSIONS
PDT showed a good efficacy and safety in treatment of pediatric RRTIs. Further high-quality and large-scale RCTs are still required to provide confirmatory evidence.
TRIAL REGISTRATION
The protocol of this study can be found at PROSPERO with the registration number of CRD42018093541.
Topics: Adjuvants, Immunologic; Child; Child, Preschool; Humans; Immunity, Cellular; Immunity, Humoral; Immunoglobulins; Infant; Infant, Newborn; Pyrrolidonecarboxylic Acid; Randomized Controlled Trials as Topic; Recurrence; Respiratory Tract Infections; T-Lymphocyte Subsets; T-Lymphocytes; Thiazolidines
PubMed: 30530167
DOI: 10.1016/j.intimp.2018.11.043 -
Journal of Cellular Physiology Apr 2021Arterial medial calcification (AMC), the deposition of hydroxyapatite in the medial layer of the arteries, is a known risk factor for cardiovascular events. Oxidative...
Arterial medial calcification (AMC), the deposition of hydroxyapatite in the medial layer of the arteries, is a known risk factor for cardiovascular events. Oxidative stress is a known inducer of AMC and endogenous antioxidants, such as glutathione (GSH), may prevent calcification. GSH synthesis, however, can be limited by cysteine levels. Therefore, we assessed the effects of the cysteine prodrug 2-oxothiazolidine-4-carboxylic acid (OTC), on vascular smooth muscle cell (VSMC) calcification to ascertain its therapeutic potential. Human aortic VSMCs were cultured in basal or mineralising medium (1 mM calcium chloride/sodium phosphate) and treated with OTC (1-5 mM) for 7 days. Cell-based assays and western blot analysis were performed to assess cell differentiation and function. OTC inhibited calcification ≤90%, which was associated with increased ectonucleotide pyrophosphatase/phosphodiesterase activity, and reduced apoptosis. In calcifying cells, OTC downregulated protein expression of osteoblast markers (Runt-related transcription factor 2 and osteopontin), while maintaining expression of VSMC markers (smooth muscle protein 22α and α-smooth muscle actin). GSH levels were significantly reduced by 90% in VSMCs cultured in calcifying conditions, which was associated with declines in expression of gamma-glutamylcysteine synthetase and GSH synthetase. Treatment of calcifying cells with OTC blocked the reduction in expression of both enzymes and prevented the decline in GSH. This study shows OTC to be a potent and effective inhibitor of in vitro VSMC calcification. It appears to maintain GSH synthesis which may, in turn, prevent apoptosis and VSMCs gaining osteoblast-like characteristics. These findings may be of clinical relevance and raise the possibility that treatment with OTC could benefit patients susceptible to AMC.
Topics: Alkaline Phosphatase; Apoptosis; Cell Differentiation; Cells, Cultured; Glutamate-Cysteine Ligase; Glutathione; Glutathione Synthase; Humans; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Osteoblasts; Phosphoric Diester Hydrolases; Prodrugs; Pyrophosphatases; Pyrrolidonecarboxylic Acid; Thiazolidines; Vascular Calcification
PubMed: 32918744
DOI: 10.1002/jcp.30036