Investigation of the effects of indoxyl sulfate, a uremic toxin, on the intracellular oxidation level and phagocytic activity using an HL-60-differentiated human macrophage cell model.

Indoxyl sulfate (IS), a uremic toxin, is a sulfate-conjugated metabolite originated from tryptophan. Accumulating uremic toxins may worsen renal diseases and further complicate related disorders including impaired immune functions under oxidative stress conditions. However, it has remained unclear whether or not IS can directly cause the cellular immune dysfunction. We investigated the effects of IS on the intracellular oxidation level and phagocytic activity in a HL-60-differantiated human macrophage cell model. Incubation of the cells in the presence of IS resulted in increasing intracellular oxidation level and decreasing phagocytic activity. In addition to inhibitors for NADH oxidase (NOX), organic anion transporting polypeptide2B1 (OATP2B1), protein kinase C (PKC), and phosphoinositide 3-kinase (PI3K), a representative antioxidant Trolox, was also shown to significantly relieve the IS-induced oxidation and restore weakened phagocytosis. Collectively, IS may directly down-regulate the phagocytic immune function of macrophages through the oxidation mechanisms including OATP2B1, PKC, PI3K, and NOX pathways. Abbreviations: CKD: Chronic kidney disease; IS: Indoxyl sulfate; ROS: Reactive oxygen species; NOX: NADH oxidase; OATP2B1: Organic anion transporting polypeptide2B1; PKC: Protein kinase C; PI3K: Phosphoinositide 3-kinase; 2-APT: 2-acetylphenothiazine.

Unique antioxidant effects of herbal leaf tea and stem tea from Moringa oleifera L. especially on superoxide anion radical generation systems.

This study aimed to investigate the unique antioxidative effects of Japanese moringa products, herbal leaf tea and stem tea, using established free radical assays, focusing on superoxide anion (O2-) radical generation systems. Hot-water extracts from moringa teas resulted in different but lower scavenging activities than Trolox in four synthetic free radical models. Interestingly, these extracts further showed higher O2- radical scavenging effects than Trolox in the phenazine methosulfate-NADH-nitroblue tetrazolium and xanthine oxidase assay systems. Incubating human neutrophils in the presence of these tea extracts rather than Trolox effectively suppressed cellular O2- radical generation. Among the eight known phenolic constituents of moringa leaves, caffeic acid and chlorogenic acid may be responsible for the O2-specific radical scavenging capacity stronger than that of Trolox. These results suggest that moringa herbal teas are a good source of natural antioxidants for preventing O2- radical-mediated disorders. Abbreviations: O2-: superoxide anion; ROS: reactive oxygen species; H2O2: hydrogen peroxide; XOD: xanthine oxidase; DPPH: 1,1-diphenyl-2-picrylhydrazyl; ABTS+: 2,2'-azinobis(2-ethylbenzothiazoline-6-sulfonic acid) cation; CPZ+: chlorpromazine cation; PMS: phenazine methosulfate; NBT: nitroblue tetrazolium; PMA: phorbol 12-myristate 13-acetate.

Modification of Wide-Band-Gap Oxide Semiconductors with Cobalt Hydroxide Nanoclusters for Visible-Light Water Oxidation.

Cobalt-based compounds, such as cobalt(II) hydroxide, are known to be good catalysts for water oxidation. Herein, we report that such cobalt species can also activate wide-band-gap semiconductors towards visible-light water oxidation. Rutile TiO2 powder, a well-known wide-band-gap semiconductor, was capable of harvesting visible light with wavelengths of up to 850 nm, and thus catalyzed water oxidation to produce molecular oxygen, when decorated with cobalt(II) hydroxide nanoclusters. To the best of our knowledge, this system constitutes the first example that a particulate photocatalytic material that is capable of water oxidation upon excitation by visible light can also operate at such long wavelengths, even when it is based on earth-abundant elements only.

Acute pancreatitis complicated with diabetic ketoacidosis following COVID-19 mRNA vaccination: a case report.

Objective: Since the onset of the coronavirus disease 2019 (COVID-19) pandemic, COVID-19 vaccination has substantially reduced mortality and hospitalization rates worldwide, with rare adverse events reported in clinical settings. Herein, we present a case of acute pancreatitis complicated by diabetic ketoacidosis (DKA) following the third COVID-19 vaccination dose. Patient: A 72-year-old male with a history of diabetes mellitus developed generalized fatigue, mild epigastric pain, nausea, and frequent vomiting after receiving the COVID-19 vaccine. Results: Blood analysis revealed elevated levels of pancreatic enzymes, hyperglycemia, and acidemia. Computed tomography revealed evidence of acute pancreatitis, leading to a diagnosis of both DKA and acute pancreatitis. Treatment with a large volume of saline and intravenous insulin improved both DKA and acute pancreatitis. After a thorough examination, no other factors capable of causing acute pancreatitis were identified. Hence, we concluded that acute pancreatitis was induced by COVID-19 vaccination. Conclusion: Acute pancreatitis is a rare but potentially life-threatening adverse event associated with COVID-19 vaccination. Delaying the treatment or diagnosis of acute pancreatitis can increase mortality risk in patients with both acute pancreatitis and DKA. Hence, it is crucial for healthcare professionals to consider the potential occurrence of acute pancreatitis and DKA following COVID-19 vaccination.

Determinants of In-hospital Death in Non-ST-segment Elevation Myocardial Infarction with Triple-vessel Disease.

Objective Triple-vessel disease (TVD) is a well-established prognostic factor for patients with acute myocardial infarction (AMI). However, there is a paucity of literature regarding the risk factors for in-hospital death in patients with non-ST-segment elevation myocardial infarction (NSTEMI) and TVD. In this retrospective study, we examined the determinants of in-hospital death in patients with NSTEMI and TVD who underwent percutaneous coronary intervention (PCI) for culprit lesions. Methods The primary objective of this study was to identify the factors associated with in-hospital death using a multivariate analysis. We included 253 patients with NSTEMI and TVD and divided them into a survivor group (n=239) and an in-hospital death group (n=14). Results Systolic blood pressure (SBP) at admission was significantly higher in the survivor group than in the in-hospital death group. The estimated glomerular filtration rate (eGFR) was also higher in the survivor group than in the in-hospital death group. In the multivariate logistic regression analysis, in-hospital death was inversely associated with the SBP at admission (odds ratio [OR] 0.984, 95% confidence interval [CI] 0.970-0.999, p<0.035) and eGFR (OR 0.966, 95% CI 0.939-0.994, p=0.019) and was associated with cardiopulmonary arrest (CPA) before PCI (OR 8.448, 95%CI 1.863-38.309, p=0.006). Conclusion In-hospital death was associated with CPA before PCI and inversely associated with the SBP at admission and eGFR in patients with NSTEMI and TVD who underwent PCI for the culprit lesion. It may be important to recognize these high-risk features in order to improve the clinical outcomes of patients with NSTEMI and TVD.

Autophagosomes accumulate in differentiated and hypertrophic adipocytes in a p53-independent manner.

Autophagy is induced by several kinds of stress, including oxidative, genotoxic, endoplasmic reticulum and nutrient stresses. The tumor suppressor p53, which is a stress sensor, plays a critical role in the regulation of autophagy. Although p53 is required for starvation (nutrient deficient stress)-induced autophagy, it is still not clear whether p53 is also required for the autophagy observed in differentiated and hypertrophic adipocytes, which accumulate excessive amounts of nutrients in the form of triglycerides. In this study, we demonstrated that starvation induces autophagy in p53-proficient adipocytes, but not in p53-deficient adipocytes as previously reported. On the other hand, autophagy was equally observed in both p53-deficient and -proficient differentiated and hypertrophic adipocytes. Similar results were obtained by in vivo analysis using white adipose tissue of high-fat diet-induced obese mice. Moreover, unexpectedly, the autophagy observed in the differentiated and hypertrophic adipocytes involved increased accumulation of autophagosomes and decreased autophagic flux. Thus, we concluded that in differentiated and hypertrophic adipocytes autophagosomes accumulate in a p53-independent manner, and this accumulation is caused by reduced autophagic flux.

Investigation of radical scavenging effects of acetaminophen, p-aminophenol and their O-sulfated conjugates.

Acetaminophen (APAP) and p-aminophenol (p-AP) are the analogous simple phenolic compounds that undergo sulfate conjugation (sulfation) by cytosolic sulfotransferases. Sulfation is generally thought to lead to the inactivation and disposal of endogenous as well as xenobiotic compounds. This study aimed to investigate the antioxidative effects of O-sulfated form of APAP and p-AP, i.e., APAPS and p-APS, in comparison with their unsulfated counterparts. Using a 1,1-diphenyl-2-picrylhydrazyl radical scavenging assay, the antioxidant capacity of APAPS was shown to be approximately 126-times lower than that of APAP. In contrast, p-APS displayed comparable activity as unsulfated p-AP. Similar trends concerning the suppressive effects of these chemicals on cellular O2- radical generation were found using an activated granulocytic neutrophil cell model. Collectively, these results indicated that, depending on the presence of an additional "active site", sulfation may not always decrease the antioxidant activities of phenolic compounds.

NMR elucidation of nonproductive binding sites of lignin models with carbohydrate-binding module of cellobiohydrolase I.

BACKGROUND: Highly efficient enzymatic saccharification of pretreated lignocellulose is a key step in achieving lignocellulosic biorefinery. Cellobiohydrolase I (Cel7A) secreted by Trichoderma reesei is an industrially used cellulase that possesses carbohydrate-binding module 1 (TrCBM1) at the C-terminal domain. The nonproductive binding of TrCBM1 to lignin significantly decreases the enzymatic saccharification efficiency and increases the cost of biomass conversion because of the additionally required enzymes. Understanding the interaction mechanism between lignin and TrCBM1 is essential for realizing a cost-effective biofuel production; however, the binding sites in lignin have not been clearly elucidated. RESULTS: Three types of 13C-labeled ß-O-4 lignin oligomer models were synthesized and characterized. The 2D 1H-13C heteronuclear single-quantum correlation (HSQC) spectra of the 13C-labeled lignin models confirmed that the three types of the 13C labels were correctly incorporated in the (1) aromatic rings and ß positions, (2) α positions, and (3) methoxy groups, respectively. The TrCBM1-binding sites in lignin were analyzed by observing NMR chemical shift perturbations (CSPs) using the synthetic 13C-labeled ß-O-4 lignin oligomer models. Obvious CSPs were observed in signals from the aromatic regions in oligomers bound to TrCBM1, whereas perturbations in the signals from aliphatic regions and methoxy groups were insignificant. These findings indicated that hydrophobic interactions and π-π stacking were dominating factors in nonproductive binding. The synthetic lignin models have two configurations whose terminal units were differently aligned and donated C(I) and C(II). The C(I) ring showed remarkable perturbation compared with the C(II), which indicated that the binding of TrCBM1 was markedly affected by the configuration of the lignin models. The long-chain lignin models (degree of polymerization (DP) 4.16-4.70) clearly bound to TrCBM1. The interactions of TrCBM1 with the short-chain lignin models (DP 2.64-3.12) were insignificant, indicating that a DP greater than 4 was necessary for TrCBM1 binding. CONCLUSION: The CSP analysis using 13C-labeled ß-O-4 lignin oligomer models enabled the identification of the TrCBM1 binding sites in lignins at the atomic level. This specific interaction analysis will provide insights for new molecular designs of cellulase having a controlled affinity to cellulose and lignin for a cost-effective biorefinery process.

Effects of indole and indoxyl on the intracellular oxidation level and phagocytic activity of differentiated HL-60 human macrophage cells.

Indoxyl, a derivative of indole originating from tryptophan, may undergo phase-II sulfate-conjugation pathway, thereby forming indoxyl sulfate (IS) in vivo. We previously reported that IS, a well-known uremic toxin, can increase the intracellular oxidation level and decrease the phagocytic activity in a differentiated HL-60 human macrophage cell model. Using the same cell model, the current study aimed to investigate whether indole and indoxyl (the metabolic precursors of indoxyl and IS, respectively) may cause macrophage immune dysfunction. Results obtained indicated that intracellular oxidation level and cytotoxicity markedly increased upon treatment with indole and indoxyl, in comparison with IS. Incubation of the cells with indole and indoxyl also resulted in attenuated phagocytic activity. Human serum albumin (HSA)-binding assay confirmed that tryptophan and IS, but not indole and indoxyl, could selectively bind to the site II in HSA. Collectively, the results indicated that indole and indoxyl may strongly down-regulate the phagocytic immune function of macrophages, whereas IS, formed upon sulfate conjugation of indoxyl, may exhibit enhanced HSA-binding capability, thereby reducing the adverse effects of indoxyl.

NMR Analysis on Molecular Interaction of Lignin with Amino Acid Residues of Carbohydrate-Binding Module from Trichoderma reesei Cel7A.

Lignocellulosic biomass is anticipated to serve as a platform for green chemicals and fuels. Nonproductive binding of lignin to cellulolytic enzymes should be avoided for conversion of lignocellulose through enzymatic saccharification. Although carbohydrate-binding modules (CBMs) of cellulolytic enzymes strongly bind to lignin, the adsorption mechanism at molecular level is still unclear. Here, we report NMR-based analyses of binding sites on CBM1 of cellobiohydrolase I (Cel7A) from a hyper-cellulase-producing fungus, Trichoderma reesei, with cellohexaose and lignins from Japanese cedar (C-MWL) and Eucalyptus globulus (E-MWL). A method was established to obtain properly folded TrCBM1. Only TrCBM1 that was expressed in freshly transformed E. coli had intact conformation. Chemical shift perturbation analyses revealed that TrCBM1 adsorbed cellohexaose in highly specific manner via two subsites, flat plane surface and cleft, which were located on the opposite side of the protein surface. Importantly, MWLs were adsorbed at multiple binding sites, including the subsites, having higher affinity than cellohexaose. G6 and Q7 were involved in lignin binding on the flat plane surface of TrCBM1, while cellohexaose preferentially interacted with N29 and Q34. TrCBM1 used much larger surface area to bind with C-MWL than E-MWL, indicating the mechanisms of adsorption toward hardwood and softwood lignins are different.

Radical scavenging effects of 1-naphthol, 2-naphthol, and their sulfate-conjugates.

1-Naphthol (1-Nap) and 2-naphthol (2-Nap) are phenolic isomers that may be subjected to sulfate conjugation in vivo. Phase-II sulfate conjugation of phenolic compounds is generally thought to result in their inactivation. This study aimed to investigate the antioxidative effects of 1-NapS and 2-NapS, in comparison with their unsulfated counterparts, using established free radical scavenging assays. Based on the calculated EC50 values, 1-NapS resulted in 5.60 to 7.35-times lower antioxidative activity than 1-Nap. In contrast, 2-NapS showed comparable activities as did the unsulfated 2-Nap. Collectively, the results obtained indicated that sulfate conjugation of the Nap isomers did not always result in the decrease of their antioxidant activity, and the antioxidant activity that remained appeared to depend on the position of sulfation.