ABSTRACT
Cost-effective and facile synthetic routes to organic ligands, along with porous materials that exhibit exceptional gas-storage properties, promise significant industrial applications. Here, a two-step synthesis of novel organophosphorus ligands without metal catalysts is reported. These ligands serve as versatile linkers for the construction of metal-organic frameworks (MOFs) incorporating various metal ions, including zinc and copper. One of the zinc-based MOFs demonstrates remarkable gas-storage properties, with a hydrogen (H2) capacity exceeding 2.5â wt% at 77â K and 100â kPa as well as a carbon dioxide (CO2) capacity exceeding 20â wt% at 298â K and 100â kPa. Furthermore, this zinc-based MOF can be synthesized through a solvothermal process on the gram scale that yields high-quality single crystals.
ABSTRACT
Depleting glutathione by xCT inhibition induces iron-dependent ferroptotic cell death, which is suppressed by lipophilic antioxidants. We screened food extracts with xCTKO-MEFs, identifying garlic extracts as particularly potent in inhibiting ferroptosis among the food extracts examined in this study. xCTKO-MEFs can serve as a convenient tool for identifying food extracts that are effective in inhibiting ferroptosis.
Subject(s)
Amino Acid Transport System y+ , Ferroptosis , Fibroblasts , Mice, Knockout , Plant Extracts , Ferroptosis/drug effects , Animals , Mice , Fibroblasts/drug effects , Fibroblasts/metabolism , Amino Acid Transport System y+/metabolism , Amino Acid Transport System y+/genetics , Amino Acid Transport System y+/antagonists & inhibitors , Plant Extracts/pharmacology , Glutathione/metabolism , Garlic/chemistry , Iron/metabolism , Antioxidants/pharmacology , Embryo, Mammalian/cytology , Embryo, Mammalian/drug effectsABSTRACT
The conditioned medium (CM) obtained from mesenchymal stromal cell (MSC) culture has excellent cell growth-promoting activity and is used for cosmetics and healthcare products. Unlike pharmaceuticals, strict efficacy verification is not legally required for these products. However, their efficacy must be substantiated as commercial products. We attempted to simplify CM production and to standardize the evaluation of the growth-promoting activity of CM. CM was obtained through the culturing of two lines of commercially available human adipose tissue-derived MSCs using MEMα with or without 10% fetal bovine serum (FBS) for 24 h. Non-CM control media were produced by the same protocol without MSCs. Growth-promoting activities of the CM were estimated by [3H]-thymidine pulse. CM were subjected to molecular weight fractionation with ultrafiltration using 10 k-, 30 k-, 50 k-, and 100 k-membranes. The FBS-free CMs showed 1.34- to 1.85-fold increases and FBS-containing CMs showed 1.45- to 1.67-fold increases in proliferation-promoting activity compared with non-CM controls, regardless of the source of the cell. The thymidine incorporation levels were approximately three times higher in FBS-containing CMs. Aged cells also showed 1.67- to 2.48-fold increases in the activity due to FBS-containing CM, but not to FBS-free CM. The CM activities were sustained even after 1 year at 4 °C. Molecular weight fractionation showed that the activity was recovered in the fraction above 100 k. Clear and stable cell-growth-promoting activity was confirmed with CMs of commercially available adipose tissue MSCs. The activity was detected in the fraction over 100 k. We propose here the importance of standardizing the production and evaluation of CMs to indicate their specific action.
Subject(s)
Adipose Tissue , Cell Proliferation , Mesenchymal Stem Cells , Humans , Mesenchymal Stem Cells/cytology , Mesenchymal Stem Cells/metabolism , Adipose Tissue/cytology , Adipose Tissue/metabolism , Culture Media, Conditioned/pharmacology , Cells, Cultured , Cell Culture Techniques/methods , Cell Culture Techniques/standardsABSTRACT
The cystine/glutamate antiporter system xc- has been identified as the major source of extracellular glutamate in several brain regions as well as a modulator of neuroinflammation, and genetic deletion of its specific subunit xCT (xCT-/-) is protective in mouse models for age-related neurological disorders. However, the previously observed oxidative shift in the plasma cystine/cysteine ratio of adult xCT-/- mice led to the hypothesis that system xc- deletion would negatively affect life- and healthspan. Still, till now the role of system xc- in physiological aging remains unexplored. We therefore studied the effect of xCT deletion on the aging process of mice, with a particular focus on the immune system, hippocampal function, and cognitive aging. We observed that male xCT-/- mice have an extended lifespan, despite an even more increased plasma cystine/cysteine ratio in aged compared to adult mice. This oxidative shift does not negatively impact the general health status of the mice. On the contrary, the age-related priming of the innate immune system, that manifested as increased LPS-induced cytokine levels and hypothermia in xCT+/+ mice, was attenuated in xCT-/- mice. While this was associated with only a very moderate shift towards a more anti-inflammatory state of the aged hippocampus, we observed changes in the hippocampal metabolome that were associated with a preserved hippocampal function and the retention of hippocampus-dependent memory in male aged xCT-/- mice. Targeting system xc- is thus not only a promising strategy to prevent cognitive decline, but also to promote healthy aging.
Subject(s)
Amino Acid Transport System y+ , Cystine , Amino Acid Transport System y+/genetics , Amino Acid Transport System y+/metabolism , Animals , Cysteine , Cystine/metabolism , Glutamic Acid , Hippocampus/metabolism , Longevity , Male , Mice , Mice, Inbred C57BLABSTRACT
BACKGROUND: Patients with diffuse idiopathic skeletal hyperostosis (DISH) are susceptible to spinal column injuries with neurological deterioration. Previous studies indicated that the prevalence of diabetes mellitus (DM) in patients with DISH was higher than that in patients without DISH. This study investigates the impact of DM on surgical outcomes for spinal fractures in patients with DISH. METHODS: We retrospectively evaluated 177 spinal fractures in patients with DISH (132 men and 45 women; mean age, 75 ± 10 years) who underwent surgery from a multicenter database. The subjects were classified into two groups according to the presence of DM. Perioperative complications, neurological status by Frankel grade, mortality rate, and status of surgical site infection (SSI) were compared between the two groups. RESULTS: DM was present in 28.2% (50/177) of the patients. The proportion of men was significantly higher in the DM group (DM group: 86.0% vs. non-DM group: 70.1%) (p = 0.03). The overall complication rate was 22.0% in the DM group and 19.7% in the non-DM group (p = 0.60). Poisson regression model revealed that SSI was significantly associated with DM (DM group: 10.0% vs. non-DM group: 2.4%, Relative risk: 4.5) (p = 0.048). Change in neurological status, mortality rate, instrumentation failure, and nonunion were similar between both groups. HbA1c and fasting blood glucose level (SSI group: 7.2% ± 1.2%, 201 ± 67 mg/dL vs. non-SSI group: 6.6% ± 1.1%, 167 ± 47 mg/dL) tended to be higher in patients with SSI; however, there was no significant difference. CONCLUSIONS: In spinal fracture in patients with DISH, although DM was an associated factor for SSI with a relative risk of 4.5, DM did not negatively impact neurological recovery. Perioperative glycemic control may be useful for preventing SSI because fasting blood glucose level was high in patients with SSI.
Subject(s)
Diabetes Mellitus , Hyperostosis, Diffuse Idiopathic Skeletal , Spinal Fractures , Aged , Aged, 80 and over , Blood Glucose , Diabetes Mellitus/epidemiology , Female , Humans , Hyperostosis, Diffuse Idiopathic Skeletal/complications , Hyperostosis, Diffuse Idiopathic Skeletal/diagnostic imaging , Hyperostosis, Diffuse Idiopathic Skeletal/surgery , Male , Retrospective Studies , Spinal Fractures/complications , Spinal Fractures/surgery , Surgical Wound Infection/epidemiologyABSTRACT
Glutathione (GSH) is synthesized from three amino acids and the overall process is highly dependent on the availability of l-cysteine (l-Cys). GSH serves as an essential cofactor for glutathione peroxidase 4 (Gpx4), which reduces phospholipid hydroperoxides. The inactivation of Gpx4 or an insufficient supply of l-Cys results in the accumulation of lipid hydroperoxides, eventually leading to iron-dependent cell death, ferroptosis. In this study, we investigated the anti-ferroptotic properties of d-cysteine (d-Cys) under conditions of dysfunction in cystine transporter, xCT. l-Cys supplementation completely rescued ferroptosis that had been induced by the erastin-mediated inhibition of xCT in Hepa 1-6 cells. Upon d-Cys supplementation, the erastin-treated cells remained completely viable for periods of up to 24â h but eventually died after 48â h. d-Cys supplementation suppressed the production of lipid peroxides, thereby ferroptosis. The addition of d-Cys sustained intracellular Cys and GSH levels to a certain extent. When Hepa 1-6 cells were treated with a combination of buthionine sulfoximine and erastin, the anti-ferroptotic effect of d-Cys was diminished. These collective results indicate that, although d-Cys is not the direct source of GSH, d-Cys supplementation protects cells from ferroptosis in a manner that is dependent on GSH synthesis via stimulating the uptake of l-Cys.
ABSTRACT
Ferroptosis is a type of iron-dependent, non-apoptotic cell death, which is typically induced by cysteine starvation or by the inhibition of glutathione peroxidase 4 (GPX4) activity with the accompanying elevation in lipid peroxidation product levels. Despite the central role of mitochondria in oxidative metabolism and hence, as main sources of superoxide, the issue of whether mitochondrial superoxide participates in the execution of ferroptosis remains unclear. To gain additional insights into this issue, we employed suppressors of the site IQ electron leak (S1QEL) and suppressors of the site IIIQo electron leak (S3QEL), small molecules that suppress mitochondrial superoxide production from complex I and III, respectively. The findings indicate that S3QEL, but not S1QEL, significantly protected mouse hepatoma Hepa 1-6 cells from lipid peroxidation and the subsequent ferroptosis induced by cysteine (Cys) starvation (cystine deprivation from culture media or xCT inhibition by erastin). The intracellular levels of Cys and GSH remained low irrespective of life or death. Moreover, S3QEL also suppressed ferroptosis in xCT-knockout mouse-derived embryonic fibroblasts, which usually die under conventional cultivating conditions due to the absence of intracellular Cys and GSH. Although it has been reported that erastin induces the hyperpolarization of the mitochondrial membrane potential, no correlation was observed between hyperpolarization and cell death in xCT-knockout cells. Collectively, these results indicate that superoxide production from complex III plays a pivotal role in the ferroptosis that is induced by Cys starvation, suggesting that protecting mitochondria is a promising therapeutic strategy for the treatment of multiple diseases featuring ferroptosis.
Subject(s)
Cysteine/deficiency , Electron Transport Complex III/metabolism , Ferroptosis , Membrane Potential, Mitochondrial , Mitochondrial Membranes/metabolism , Superoxides/metabolism , Animals , HeLa Cells , Humans , MiceABSTRACT
Ferroptosis is a type of iron-dependent necrotic cell death, which is typically triggered by the depletion of intracellular glutathione (GSH), which is associated with increased lipid peroxidation. Nitric oxide (NO) is a highly reactive gaseous radical mediator with anti-oxidation properties that terminates lipid peroxidation reactions. In the current study, we report the anti-ferroptotic action of NOC18, an NO donor that spontaneously releases NO, in cells under various ferroptotic conditions in vitro. Our results indicate that, when mouse hepatoma Hepa 1-6 cells are incubated with NOC18, cell death induced by various ferroptotic stimuli such as cysteine (Cys) starvation, the inhibition of glutathione peroxidase 4 (GPX4) and treatment with tertiary-butyl hydroperoxide (TBHP) is significantly reduced. Treatment with NOC18 failed to improve the decrease in the levels of Cys or GSH and the accumulation of ferrous iron upon ferroptotic stimuli. The fluorescent intensity of C11-BODIPY581/591, a probe that is used to detect lipid peroxidation products, was increased somewhat by treatment with NOC18 under conditions of Cys starvation, and the accumulation of lipid peroxidation end-products, as evidenced by the levels of 4-hydroxynonenal, were effectively suppressed. The pre-incubation of TBHP with NOC7, a short-lived NO donor completely eliminated its ability to trigger ferroptosis. These collective results indicate that NO exerts a cytoprotective action against various ferroptotic stimuli by aborting the lipid peroxidation chain reaction.
Subject(s)
Ferroptosis/drug effects , Nitric Oxide/pharmacology , Protective Agents/pharmacology , Animals , Cell Death/drug effects , Lipid Peroxidation/drug effects , Mice , Reactive Oxygen Species/antagonists & inhibitors , Reactive Oxygen Species/metabolism , Tumor Cells, CulturedABSTRACT
BACKGROUND: Spinal shortening osteotomy (SSO) reduces the tension indirectly in the spinal cord and minimizes perioperative complications. However, the most effective and safe length to which the spine can be shortened is still unknown. In our practice, we use somatosensory-evoked potentials, motor-evoked potentials, and intraoperative ultrasonography when performing SSO. This study aimed to introduce the clinical outcomes of our SSO technique for tethered cord syndrome (TCS) in adults. METHODS: This retrospective study included 7 adult patients (2 males and 5 females) with TCS treated between December 2010 and December 2018. The average age and average preoperative duration were 40 and 5 years, respectively. All patients received SSO with somatosensory-evoked potentials, motor-evoked potentials, and ultrasonography. After surgery, all patients were followed for an average of 4 years. RESULTS: The mean operation time was 328 (284-414) min for SSO. The mean blood loss was 828 ml (501-1252 ml). Postoperative bony fusion was confirmed in all patients. Postoperative computed tomography (CT) demonstrated an average of 16 mm (11-20 mm) of spinal column shortening, compared with preoperative CT. Clinical improvements were obtained in all 7 cases, and there was no case of exacerbation. An indicator of shortening is that the ultrasonography gives pulsation and relaxation of the spinal cord. There were no abnormalities observed while monitoring the spinal cord. CONCLUSIONS: Spinal shortening should be done under somatosensory-evoked potentials, motor-evoked potentials, and intraoperative ultrasonography to obtain safe and sufficient shortening.
Subject(s)
Neural Tube Defects , Spine , Adult , Female , Humans , Male , Neural Tube Defects/diagnostic imaging , Neural Tube Defects/surgery , Osteotomy , Retrospective Studies , Spinal Cord , UltrasonographyABSTRACT
BACKGROUND: Patients with DISH are susceptible to spinal fractures and subsequent neurological impairment, including after minor trauma. However, DISH is often asymptomatic and fractures may have minimal symptoms, which may lead to delayed diagnosis. The purpose of this study was to identify risk factors for delayed diagnosis of spinal fractures in patients with diffuse idiopathic skeletal hyperostosis (DISH). METHODS: The subjects were 285 patients with DISH surgically treated at 18 medical centers from 2005 to 2015. Cause of injury, imaging findings, neurological status at the times of injury and first hospital examination, and the time from injury to diagnosis were recorded. A delayed diagnosis was defined as that made >24 h after injury. RESULTS: Main causes of injury were minor trauma due to a fall from a standing or sitting position (51%) and high-energy trauma due to a fall from a high place (29%) or a traffic accident (12%). Delayed diagnosis occurred in 115 patients (40%; 35 females, 80 males; mean age 76.0 ± 10.4 years), while 170 (60%; 29 females, 141 males; mean age 74.6 ± 12.8 years) had early diagnosis. Delayed group had a significantly higher rate of minor trauma (n = 73, 63% vs. n = 73, 43%), significantly more Frankel grade E (intact neurological status) cases at the time of injury (n = 79, 69% vs. n = 73, 43%), and greater deterioration of Frankel grade from injury to diagnosis (34% vs. 8%, p < 0.01). In multivariate analysis, a minor trauma fall (OR 2.08; P < 0.05) and Frankel grade E at the time of injury (OR 2.29; P < 0.01) were significantly associated with delayed diagnosis. CONCLUSION: In patients with DISH, it is important to keep in mind the possibility of spinal fracture, even in a situation in which patient sustained only minor trauma and shows no neurological deficit. This is because delayed diagnosis of spinal fracture can cause subsequent neurological deterioration.
Subject(s)
Hyperostosis, Diffuse Idiopathic Skeletal , Spinal Fractures , Aged , Aged, 80 and over , Delayed Diagnosis , Diagnostic Imaging , Female , Humans , Hyperostosis, Diffuse Idiopathic Skeletal/diagnosis , Hyperostosis, Diffuse Idiopathic Skeletal/diagnostic imaging , Male , Middle Aged , Risk Factors , Spinal Fractures/diagnostic imaging , Spinal Fractures/epidemiologyABSTRACT
Some γ-glutamylpeptides in blood plasma are putative biomarkers for pathological conditions of the liver. γ-Glutamyltransferase (GGT) and γ-glutamylcysteine synthetase (γ-GCS) are two such potential enzymes that are responsible for the production of γ-glutamylpeptides. GGT produces γ-glutamylpeptides by transferring the γ-glutamyl moiety from glutathione to an amino acid or a peptide. γ-GCS normally catalyzes the production of γ-glutamylcysteine from glutamate and cysteine in the glutathione-synthesizing reaction, but other amino acids can also serve as an acceptor of a γ-glutamyl group, thus resulting in the formation of a variety of γ-glutamylpeptides. Based on liquid chromatography-mass spectrometry analyses, we observed differences in the distribution of γ-glutamylpeptides between the liver and kidney and were able to measure the activities of γ-GCS as well as the GGT reactions by quantifying the resulting γ-glutamylpeptides. The enzymatic characterization of γ-GCS in liver homogenates indicated that several γ-glutamylpeptides including γ-glutamyltaurine are actually produced. Cys showed the lowest Km value (0.06 mM) while other amino acids had much higher Km values (ranging from 21 to 1800 mM). The moderate Km values for these amino acids suggest that they were not the preferred amino acids in this conversion but were utilized as acceptor substrates for the production of the corresponding γ-glutamylpeptides by the γ-GCS reaction under Cys-deficient conditions. Thus, the production of these γ-glutamylpeptides by γ-GCS is directly correlated with a low Cys content, suggesting that their measurement in blood plasma could be useful for predicting the presymptomatic disease state of the liver with a defect in GSH redox balance.
Subject(s)
Dipeptides/metabolism , Glutamate-Cysteine Ligase/metabolism , Glutathione/metabolism , Peptides/metabolism , gamma-Glutamyltransferase/metabolism , Amino Acids , Animals , Chromatography, Liquid , Cysteine/metabolism , Dipeptides/blood , Glutamate-Cysteine Ligase/genetics , Kidney/metabolism , Liver/metabolism , Mass Spectrometry , Mice , Peptides/chemistryABSTRACT
Ferroptosis is characterized by an iron-dependent cell death with increased lipid peroxidation and is typically induced by either a decrease in glutathione (GSH) levels due to an insufficient supply of cysteine (Cys) or the inhibition of phospholipid hydroperoxide glutathione peroxidase (Gpx4). While lipid peroxides are the direct trigger for ferroptosis, the issue of how radical species involve in the cytocidal process remains unclear. To gain insights into this issue, we employed edaravone, a free radical scavenger that is clinically approved for the treatment of acute ischemic strokes and amyotrophic lateral sclerosis (ALS), against ferroptotic cell death caused by various situations, notably under cystine deprivation. We initially investigated the effects of edaravone on ferroptosis in mouse hepatoma Hepa 1-6â¯cells cultivated in cystine-free medium and found that edaravone largely suppressed ferroptosis. Ferroptosis that was induced in the cells by the use of inhibitors for xCT or Gpx4 was also suppressed by edaravone. Moreover, edaravone also suppressed ferroptosis in xCT-knockout mouse-derived embryonic fibroblasts, which usually die in normal cultivating conditions due to the depletion of intracellular Cys and GSH. Although the edaravone treatment had no effects on the intracellular levels of Cys and GSH, both of which remained low in Hepa 1-6â¯cells under conditions of cystine deprivation, the causative factors for ferroptosis, including ferrous iron and lipid peroxide levels, were significantly suppressed. Collectively, these results indicate that radical species produced at the initial stage of the cytocidal process under Cys-deprived conditions trigger ferroptosis and scavenging these radicals by edaravone represents a promising treatment.
Subject(s)
Apoptosis/drug effects , Cell Death/drug effects , Ferroptosis/drug effects , Free Radical Scavengers/pharmacology , Protective Agents/pharmacology , Animals , Cell Line, Tumor , Cysteine/metabolism , Edaravone/pharmacology , Glutathione/metabolism , Glutathione Peroxidase/metabolism , Iron/metabolism , Lipid Peroxidation/drug effects , Mice , Mice, Knockout , Reactive Oxygen Species/metabolismABSTRACT
PURPOSE: Gastroesophageal reflux disease (GERD) is reported as one of the symptoms of adult spinal deformity (ASD). Little is known about the mid- to long-term improvement in GERD symptoms after ASD surgery. Therefore, this retrospective study from prospectively collected database aimed to investigate GERD symptoms in patients for a minimum of 2 years after ASD corrective surgery. METHODS: Records from 230 patients (mean age: 64 years) who underwent ASD surgery were examined using the frequency scale for the symptoms of GERD (FSSG) questionnaires for the diagnosis of GERD. FSSG scores and radiographic parameters were investigated preoperatively and postoperatively at 6 months and 1, 2, and 5 years. RESULTS: In total, 90 (39%) patients were preoperatively diagnosed with GERD defined by FSSG score ≥ 8 points. Radiographic results showed that the corrective surgeries improved local and global alignments. In the GERD patients, preoperative FSSG scores (16.1 ± 7.3 points) significantly improved to 7.7 ± 7.4 points within 6 months postoperatively (p < 0.001), and postoperative FSSG scores maintained at 1 year (9.9 ± 8.2 points, p = 0.061), 2 years (9.7 ± 8.2 points, p = 0.086), and 5 years (9.4 ± 8.0 points, p = 0.177). Among the GERD group, 62 patients (69%; improvement cases) showed improvement in GERD symptoms defined by FSSG score < 8 points within 6 months postoperatively. CONCLUSIONS: Among ASD patients, 39% were diagnosed with GERD. In 69% of these patients, GERD symptoms improved within 6 months of corrective surgery and maintained up to 5 years postoperatively. These slides can be retrieved under Electronic Supplementary Material.
Subject(s)
Gastroesophageal Reflux , Aged , Female , Follow-Up Studies , Gastroesophageal Reflux/surgery , Humans , Male , Middle Aged , Postoperative Period , Retrospective Studies , Surveys and QuestionnairesABSTRACT
PURPOSE: There is controversy regarding age-related deterioration of spinal sagittal alignment in cross-sectional study. Although we reported that deterioration in spinal alignment originated at the cervical spine in males and the pelvis in females, others studies have indicated that the lumbar spine is initially implicated in both sexes. The purpose of this study was to clarify these differences in a longitudinal cohort study. METHODS: Our analysis was based on 237 individuals aged 60-89 years who participated in our health screening study in 2014 and 2018. They were classified into six groups by birth year and sex: 60-69 years (26 males, 49 females); 70-79 years (35 males, 88 females); and 80-89 years (19 males, 20 females). The following parameters were measured from standing radiographs: pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), thoracic kyphosis, T1 slope, cervical lordosis, C7 sagittal vertical axis (C7 SVA), and C2-7 SVA. RESULTS: In males, the first significant change was an increase in the PT angle (19°, in 2014, to 21°, in 2018) in the 80-89 years age group (P < 0.05), with no significant deterioration in cervical parameters. In females, spinal deterioration included a change in the SS (32°-30°), PT (18°-20°), and SVA (- 8 to 6 mm) in the 60-69 years age group (P < 0.05), with no change in the LL. CONCLUSIONS: Contrary to prior studies, our longitudinal data indicated that deterioration in spinal alignment originates in the pelvis for both sex but develops earlier in females than males.
Subject(s)
Kyphosis , Lordosis , Pelvis , Aged , Aged, 80 and over , Cohort Studies , Cross-Sectional Studies , Female , Humans , Longitudinal Studies , Lumbar Vertebrae/diagnostic imaging , Male , Middle Aged , Pelvis/diagnostic imagingABSTRACT
Unfortunately, figure 3 was incorrectly published in the original publication. The complete correct figure 3 is given below.
ABSTRACT
Singlet oxygen causes a cytotoxic process in tumor cells in photodynamic therapy (PDT) and skin photoaging. The mechanism responsible for this cytotoxicity is, however, not fully understood. 1-Methylnaphthalene-4-propionate endoperoxide (MNPE) is a cell-permeable endoperoxide that generates pure singlet oxygen. We previously reported that cell death induced by MNPE did not show the typical profile of apoptosis, and the cause of this cell death remains elusive. We report herein on an investigation of the mechanism for MNPE-induced cell death from the view point of ferroptosis. The findings indicate that the MNPE treatment decreased the viabilities of mouse hepatoma Hepa 1-6â¯cells in vitro, and that this decrease was accompanied by increases in the concentrations of both intracellular ferrous iron and the level of lipid peroxidation, but that the caspase-mediated apoptotic pathway was not activated. The intracellular levels of cysteine and glutathione were not affected by the MNPE treatment. Importantly, an assay of lactate dehydrogenase activity revealed that the cell death caused by MNPE was suppressed by ferrostatin-1, a ferroptosis-specific inhibitor. Collectively, these results strongly indicate that ferroptosis is the main cell death pathway induced by singlet oxygen.
Subject(s)
Ferroptosis/drug effects , Naphthalenes/pharmacology , Peroxides/pharmacology , Singlet Oxygen/metabolism , Animals , Cell Line, Tumor , Glutathione/metabolism , Lipid Peroxidation/drug effects , Mice , Reactive Oxygen Species/metabolismABSTRACT
γ-Glutamylpeptides are largely produced via the action of γ-glutamylcysteine synthetase or γ-glutamyltransferase (GGT). GGT transfers the γ-glutamyl moiety from glutathione (GSH) and other γ-glutamyl compounds to amino acids, peptides, or water. A conventional GGT assay employs a synthetic donor substrate, which facilitates monitoring cleavage activity by means of colorimetric analyses but provides no information on the resulting γ-glutamylpeptides. In this study, we report on the use of liquid chromatography-mass spectrometry (LC-MS) to quantitatively measure the levels of 21 γ-glutamylpeptides including GSH and 45 amino acids, including Cys. Authentic compounds consisting of 17 chemically synthesized and commercially available 4 γ-glutamylpeptides were adopted as references. We applied this method to the characterization of γ-glutamylpeptides in blood plasma and livers of mice that had been treated with an overdose of acetaminophen. The established LC-MS-based assay was found to be useful for characterizing the γ-glutamylation reaction under in vivo and in vitro conditions and was clearly helpful for understanding the physiological significance of the production of γ-glutamylpeptides.
Subject(s)
Chromatography, Liquid/methods , Kidney/metabolism , Liver/metabolism , Mass Spectrometry/methods , Peptides/analysis , gamma-Glutamyltransferase/metabolism , Animals , Glutathione/metabolism , Mice , Mice, Inbred C57BLABSTRACT
Ferroptosis is a form of regulated necrotic cell death controlled by glutathione peroxidase 4 (GPX4). At present, mechanisms that could predict sensitivity and/or resistance and that may be exploited to modulate ferroptosis are needed. We applied two independent approaches-a genome-wide CRISPR-based genetic screen and microarray analysis of ferroptosis-resistant cell lines-to uncover acyl-CoA synthetase long-chain family member 4 (ACSL4) as an essential component for ferroptosis execution. Specifically, Gpx4-Acsl4 double-knockout cells showed marked resistance to ferroptosis. Mechanistically, ACSL4 enriched cellular membranes with long polyunsaturated ω6 fatty acids. Moreover, ACSL4 was preferentially expressed in a panel of basal-like breast cancer cell lines and predicted their sensitivity to ferroptosis. Pharmacological targeting of ACSL4 with thiazolidinediones, a class of antidiabetic compound, ameliorated tissue demise in a mouse model of ferroptosis, suggesting that ACSL4 inhibition is a viable therapeutic approach to preventing ferroptosis-related diseases.
Subject(s)
Apoptosis , Coenzyme A Ligases/metabolism , Glutathione Peroxidase/metabolism , Mammary Neoplasms, Experimental/metabolism , Animals , Cell Death/drug effects , Cell Line , Cell Survival/drug effects , Coenzyme A Ligases/antagonists & inhibitors , Coenzyme A Ligases/deficiency , Female , Glutathione Peroxidase/deficiency , Humans , Hypoglycemic Agents/pharmacology , Mammary Neoplasms, Experimental/drug therapy , Mammary Neoplasms, Experimental/pathology , Mice , Mice, Knockout , Necrosis , Phospholipid Hydroperoxide Glutathione Peroxidase , Thiazolidinediones/pharmacologyABSTRACT
BACKGROUND: Diffuse idiopathic skeletal hyperostosis (DISH) increases the spine's susceptibility to unstable fractures that can cause neurological deterioration. However, the detail of injury is still unclear. A nationwide multicenter retrospective study was conducted to assess the clinical characteristics and radiographic features of spinal fractures in patients with DISH. METHODS: Patients were eligible for this study if they 1) had DISH, defined as flowing ossification along the anterolateral aspect of at least four contiguous vertebral bodies, and 2) had an injury in the ankylosing spine. This study included 285 patients with DISH (221 males, 64 females; mean age 75.2 ± 9.5 years). RESULTS: The major cause of injury was falling from a standing or sitting position; this affected 146 patients (51.2%). Diagnosis of the fracture was delayed in 115 patients (40.4%). Later neurological deterioration by one or more Frankel grade was seen in 87 patients (30.5%). The following factors were significantly associated with neurological deficits: delayed diagnosis (p = 0.033), injury of the posterior column (p = 0.021), and the presence of ossification of the posterior longitudinal ligament (OPLL) (p < 0.001). The majority of patients (n = 241, 84.6%) were treated surgically, most commonly by conventional open posterior fixation (n = 199, 69.8%). Neurological improvement was seen in 20.0% of the conservatively treated patients, and in 47.0% of the patients treated surgically. CONCLUSIONS: Minor trauma could cause spinal fractures in DISH patients. Delayed diagnosis, injury of the posterior column, and the presence of OPLL were significantly associated with neurological deterioration. Patients with neurological deficits or unstable fractures should be treated by fixation surgery.
Subject(s)
Hyperostosis, Diffuse Idiopathic Skeletal/complications , Spinal Fractures/etiology , Adult , Aged , Aged, 80 and over , Female , Fracture Fixation , Humans , Hyperostosis, Diffuse Idiopathic Skeletal/diagnostic imaging , Hyperostosis, Diffuse Idiopathic Skeletal/surgery , Male , Middle Aged , Radiography , Retrospective Studies , Risk Factors , Spinal Fractures/diagnostic imaging , Spinal Fractures/surgery , Spinal Fusion , Surveys and QuestionnairesABSTRACT
AKR1A, an aldo-keto reductase, is involved in the synthesis of ascorbic acid as well as the reduction of a variety of aldehyde compounds. AKR1A-/- mice produce considerably less ascorbic acid (about 10%) compared to AKR1A+/+ mice and require ascorbic acid supplementation in order to breed. To elucidate the roles played by AKR1A in spatial memory, AKR1A-/- male mice were weaned at 4 weeks of age and groups that received ascorbic acid supplementation and no supplementation were subjected to a Morris water maze test. Juvenile AKR1A-/- mice that received no supplementation showed impaired spatial memory formation, even though about 70% of the ascorbic acid remained in the brains of the AKR1A-/- mice at day 7 after weaning. To the contrary, the young adult AKR1A-/- mice at 13-15 weeks of age maintained only 15% of ascorbic acid but showed no significant difference in the spatial memory compared with the AKR1A+/+ mice or ascorbic acid-supplemented AKR1A-/- mice. It is conceivable that juvenile mice require more ascorbic acid for the appropriate level of formation of spatial memory and that maturation of the neural system renders the memory forming process less sensitive to an ascorbic acid insufficiency.