Thioredoxin and glutaredoxin systems under oxidative and nitrosative stress

Our knowledge about reactive oxygen species (ROS) and reactive nitrogen species (RNS) has been changed from simple damaging molecules to redox signaling mediators. ROS/RNS mediated signaling is mainly based on the reversible post-translational modifications of cysteine which works as a switch for protein functions. A proper amount of ROS/RNS is necessary to trigger such signaling, while excessive amount will lead to oxidative and nitrosative stress, which was recently defined as the disruption of redox signaling and control. In order to maintain the redox homeostasis, mammalian cells are equipped with two major antioxidant systems: the thioredoxin (Trx) system, which is composed of Trx, thioredoxin reductase (TrxR) and NADPH, and the glutaredoxin (Grx) system, which is grouped by Grx, glutathione (GSH), glutathione reductase (GR) and NADPH. Both systems play important roles in counteracting ROS/RNS and regulating redox signaling. In Paper I, we investigated the toxicity of several arsenic compounds on mammalian cells. We found that arsenical-induced cytotoxicity was related to inhibition of TrxR, suggesting an important role of TrxR for cell survival and potential usage as an anti-cancer target. Among the compounds, As6 and As7 exhibited higher cytotoxicity by directly oxidizing Trx1 and leading to the formation of a structural disulfide between Cys63 and Cys69. The formation of Cys63-Cys69 disulfide blocked the electron transfer from TrxR to peroxiredoxin (Prx) via Trx1, which allowed H2O2 to accumulate and activate the Nrf2 antioxidant pathway. This study highlighted the importance of the structural cysteines in human Trx1 and provided a potential rational design of new anticancer agents. In Paper II, we studied the effect of Apatone, a vitamin C and vitamin K3 combination used for cancer treatment, on antioxidant systems. We found that Apatone induced oxidative stress in various cancer cell lines which is characterized by GSH depletion, protein glutathionylation, and Trx1 oxidation. In addition, it inhibited ribonucleotide reductase (RNR), which is essential for DNA replication and repair, and caused replicative stress. A caspase-independent cell death pathway was also elucidated that Apatone elevated lipid peroxidation which triggered the nuclear translocation of apoptosis-inducing factor (AIF). We conclude that Apatone works by dramatically disturbing the redox balance in cancer cells. In Paper III, the role of nitric oxide (NO) during trypanosome infection was studied by using a Trypanosoma Brucei infected inducible nitric oxide synthase knocked (inos-/-) mice model. NO exhibited a protective role by maintaining the integrity of blood-brain-barrier (BBB). We found that macrophage-derived NO curbed the inflammatory effect of TNF-α by S-nitrosylating the p65 subunit of NF-κB, a transcription factor staying in the center of inflammation. Matrix metalloproteinase 9 (MMP9), one of the targets of NF-κB degrading BBB, was also decreased by NO. Thus we conclude that NO plays a protective role during parasite infection by serving as a negative feedback for neuronal inflammatory signaling. In Paper IV, we characterized Grxs as S-denitrosylases catalyzing the reversible S-nitrosylation. We observed that reduced human dithiol Grx1 and Grx2a denitrosylated S-nitrosothiols (SNOs) directly by the active site dithiol. GSH can denitrosylate part of protein SNOs, while some of them are stable in the presence of high concentration of GSH. Both dithiol and monothiol Grxs exhibited denitrosylation ability to GSH-stable SNOs. We proposed Grxs catalyze S-denitrosylation via both dithiol and monothiol mechanisms. To summarize, this thesis consolidated the importance of Trx and Grx systems in fighting against ROS/RNS and mediating redox signaling in mammalian cells

The Chronic Protective Effects of Limb Remote Preconditioning and the Underlying Mechanisms Involved in Inflammatory Factors in Rat Stroke

We recently demonstrated that limb remote preconditioning (LRP) protects against focal ischemia measured 2 days post-stroke. Here, we studied whether LRP provides long-term protection and improves neurological function. We also investigated whether LRP transmits its protective signaling via the afferent nerve pathways from the preconditioned limb to the ischemic brain and whether inflammatory factors are involved in LRP, including the novel galectin-9/Tim-3 inflammatory cell signaling pathway, which induces cell death in lymphocytes. LRP in the left hind femoral artery was performed immediately before stroke. LRP reduced brain injury size both at 2 days and 60 days post-stroke and improved behavioral outcomes for up to 2 months. The sensory nerve inhibitors capsaicin and hexamethonium, a ganglion blocker, abolished the protective effects of LRP. In addition, LRP inhibited edema formation and blood-brain barrier (BBB) permeability measured 2 days post-stroke. Western blot and immunostaining analysis showed that LRP inhibited protein expression of both galectin-9 and T-cell immunoglobulin domain and mucin domain 3 (Tim-3), which were increased after stroke. In addition, LRP decreased iNOS and nitrotyrosine protein expression after stroke. In conclusion, LRP executes long-term protective effects against stroke and may block brain injury by inhibiting activities of the galectin-9/Tim-3 pathway, iNOS, and nitrotyrosine

Biološka karakterizacija izolata golubljeg paramiksovirusa 1 i analiza njegove patogenosti u SPF pilića

Pigeon paramyxovirus type 1 (PPMV-1) is considered as an antigenic variant of Newcastle Disease leading to high mortality and significant economic losses to the poultry industry. However, the pathogenicity of PPMV-1 to chickens is still unclear. Herein, we reported the biological characterization of the isolated PPMV-1 from the diseased pigeons suspected to Newcastle Disease and studied its pathogenicity in SPF chickens. The phylogenetic tree and evolution distances revealed that the new isolate belonged to a VI.2.1.1.2.2 sub-genotype of NDV. Despite the cleavage motif of the F protein containing the 112RRQKR↓F117 sequence associated with virulent NDV strains, and the value of MDT and ICPI of the isolate showing mesogenic characteristics, the challenge trial showed that the isolate had weak pathogenicity to chickens while causing lesions in multiple tissues and organs in pigeons.Golublji paramiksovirus tipa 1 (PPMV-1) smatra se antigenskom varijantom njukaslske bolesti koja uzrokuje visoku smrtnost i znatne ekonomske gubitke u peradarskoj industriji. Patogenost virusa PPMV-1 u pilića međutim još uvijek nije jasna. U ovom je radu provedena biološka karakterizacija PPMV-1 izoliranog iz golubova za koje se sumnja da su oboljeli od njukaslske bolesti te je istražena njihova patogenost u SPF pilića. Filogenetsko stablo i evolucijske udaljenosti otkrili su da novi izolat pripada podgenotipu VI.2.1.1.2.2 virusa njukaslske bolesti (NDV). Unatoč motivu u mjestu cijepanja F-proteina koji sadržava sekvenciju 112RRQKR↓F117 povezanu s virulentnim sojevima NDV-a, vrijednosti MDT-a i ICPI-ja izolata pokazale su mezogene značajke. Ovo probno istraživanje je pokazalo da su izolati PPMV-1 slabo patogeni u pilića, dok u golubova uzrokuju lezije na više organa i tkiva

Primitive-based 3D Abstraction Method for Spacecraft ISAR Images

Inverse Synthetic Aperture Radar (ISAR) images of spacecraft are composed of discrete scatterers that exhibit weak texture, high dynamics, and discontinuity. These characteristics result in sparse point clouds obtained using traditional algorithms for the Three-Dimensional (3D) reconstruction of spacecraft ISAR images. Furthermore, using point clouds to comprehensively describe the complete shape of targets is difficult, which consequently hampers the accurate extraction of the structural and pose parameters of the target. To address this problem, considering that space targets usually have specific modular structures, this paper proposes a method for abstracting parametric structural primitives from space target ISAR images to represent their 3D structures. First, the energy accumulation algorithm is used to obtain the sparse point cloud of the target from ISAR images. Subsequently, the point cloud is fitted using parameterized primitives. Finally, primitives are projected onto the ISAR imaging plane and optimized by maximizing their similarity with the target image to obtain the optimal 3D representation of the target primitives. Compared with the traditional point cloud 3D reconstruction, this method can provide a more complete description of the three-dimensional structure of the target. Meanwhile, primitive parameters obtained using this method represent the attitude and structure of the target and can directly support subsequent tasks such as target recognition and analysis. Simulation experiments demonstrate that this method can effectively achieve the 3D abstraction of space targets based on ISAR sequential images

The Global Response of Cronobacter sakazakii Cells to Amino Acid Deficiency

Cronobacter species can cause necrotizing enterocolitis and meningitis in neonates and infants, their infection is closely relevant to their responses to extreme growth conditions. In this study, the response of Cronobacter species to amino acid deficiency has been investigated. Four Cronobacter species formed smooth colonies when grown on the solid LB medium, but formed mucoid colonies when grown on the amino acid deficient M9 medium. When the mucoid colonies were stained with tannin mordant, exopolysaccharide around the cells could be discerned. The exopolysaccharide was isolated, analyzed, and identified as colanic acid. When genes wcaD and wcaE relevant to colanic acid biosynthesis were deleted in Cronobacter sakazakii BAA-894, no exopolysaccharide could be produced, confirming the exopolysaccharide formed in C. sakazakii grown in M9 is colanic acid. On the other hand, when genes rcsA, rcsB, rcsC, rcsD, or rcsF relevant to Rcs phosphorelay system was deleted in C. sakazakii BAA-894, colanic acid could not be produced, suggesting that the production of colanic acid in C. sakazakii is regulated by Rcs phosphorelay system. Furthermore, C. sakazakii BAA-894 grown in M9 supplemented with amino acids could not produce exopolysaccharide. Transcriptomes of C. sakazakii BAA-894 grown in M9 or LB were analyzed. A total of 3956 genes were differentially expressed in M9, of which 2339 were up-regulated and 1617 were down-regulated. When C. sakazakii BAA-894 was grown in M9, the genes relevant to the biosynthesis of exopolysaccharide were significantly up-regulated; on the other hand, the genes relevant to the flagellum formation and chemotaxis were significantly down-regulated; in addition, most genes relevant to various amino acid biosynthesis were also significantly regulated. The results demonstrate that amino acid deficiency has a global impact on C. sakazakii cells

Cryotherapy Combined with Warm Transfusion Apply to Serious Burns in a Rabbit Model: An Experimental Study

A bottoming 275 kilowatt planar solid oxide fuel cell (SOFC) gas turbine (GT) hybrid system control approach has been conceptualized and designed. Based on previously published modeling techniques, a dynamic model is developed that captures the physics sufficient for dynamic simulation of all processes that affect the system with time scales greater than ten milliseconds. The dynamic model was used to make system design improvements to enable the system to operate dynamically over a wide range of power output (15 to 100% power). The wide range of operation was possible by burning supplementary fuel in the combustor and operating the turbine at variable speed for improved thermal management. The dynamic model was employed to design a control strategy for the system. Analyses of the relative gain array (RGA) of the system at several operating points gave insight into input/output (I/O) pairing for decentralized control. Particularly, the analyses indicate that for SOFC/GT hybrid plants that use voltage as a controlled variable it is beneficial to control system power by manipulating fuel cell current and to control fuel cell voltage by manipulating the anode fuel flowrate. To control the stack temperature during transient load changes, a cascade control structure is employed in which a fast inner loop that maintains the GT shaft speed receives its setpoint from a slower outer loop that maintains the stack temperature. Fuel can be added to the combustor to maintain the turbine inlet temperature for the lower operating power conditions. To maintain fuel utilization and to prevent fuel starvation in the fuel cell, fuel is supplied to the fuel cell proportionally to the stack current. In addition, voltage is used as an indicator of varying fuel concentrations allowing the fuel flow to be adjusted accordingly. Using voltage as a sensor is shown to be a potential solution to making SOFC systems robust to varying fuel compositions. The simulation tool proved effective for fuel cell/GT hybrid system control system development. The resulting SOFC/GT system control approach is shown to have transient load-following capability over a wide range of power, ambient temperature, and fuel concentration variations. Copyright © 2006 by ASME

Selenium status in diet affects acetaminophen-induced hepatotoxicity via interruption of redox environment

Aims: Drug-induced liver injury, especially acetaminophen (APAP)-induced liver injury, is a leading cause of liver failure worldwide. Mouse models were used to evaluate the effect of microelement selenium levels on the cellular redox environment and consequent hepatotoxicity of APAP. Results: APAP treatment affected mouse liver selenoprotein thioredoxin reductase (TrxR) activity and glutathione (GSH) level in a dose- and time-dependent manner. Decrease of mouse liver TrxR activity and glutathione level was an early event, and occurred concurrently with liver damage. The decreases in the GSH/glutathione disulfide form (GSSG) ratio and TrxR activity, and the increase of protein S-glutathionylation were correlated with the APAP-induced hepatotoxicity. Moreover, in APAP-treated mice both mild deprivation and excess supplementation with selenium increased the severity of liver injury compared with those observed in mice with normal dietary selenium levels. An increase in the oxidation state of the TrxR-mediated system, including cytosolic thioredoxin1 (Trx1) and peroxiredoxin1/2 (Prx1/2), and mitochondrial Trx2 and Prx3, was found in the livers from mice reared on selenium-deficient and excess selenium-supplemented diets upon APAP treatment. Innovation: This work demonstrates that both Trx and GSH systems are susceptible to APAP toxicity in vivo, and that the thiol-dependent redox environment is a key factor in determining the extent of APAP-induced hepatotoxicity. Dietary selenium and selenoproteins play critical roles in protecting mice against APAP overdose. Conclusion: APAP treatment in mice interrupts the function of the Trx and GSH systems, which are the main enzymatic antioxidant systems, in both the cytosol and mitochondria. Dietary selenium deficiency and excess supplementation both increase the risk of APAP-induced hepatotoxicity.</p

Case report: Acute pancreatitis in lung adenocarcinoma with small cell transformation after multiple line targeted therapy

In lung cancer, metastasis to the liver, bones, brain, and adrenal glands is more commonly observed, whereas pancreatic metastasis from lung cancer is relatively rare. We present a case of a patient with an 8-year history of lung adenocarcinoma (LUAD) who was admitted to our institution exhibiting symptoms consistent with acute pancreatitis. Subsequent histopathological examination through puncture confirmed the occurrence of pancreatic metastasis originating from small cell lung cancer (SCLC). During a multidisciplinary team discussion, we reached a consensus in diagnosing the patient with post-transformation small cell carcinoma alongside moderately severe pancreatitis, which was determined to be a consequence of pancreatic metastasis. The patient received a regimen of etoposide and cisplatin chemotherapy. This unique clinical case highlights the importance of further investigating the factors contributing to pancreatic metastasis in patients with lung cancer, as the underlying mechanisms remain unclear. Understanding these exceptional metastatic events is vital in devising effective therapeutic strategies and improving patient prognosis. Our findings emphasize the need for continued surveillance and comprehensive management of lung cancer patients, particularly those with resistant forms of the disease, to promptly identify and address the progression of metastatic events to uncommon sites such as the pancreas

Electrophoretic deposition and laser cladding of bioglass coating on Ti

Bioglass coatings derived from electrophoretic deposition method were fused on Ti surface by laser cladding process using a continuous CO laser. The specimens were studied by field-emission scanning electron microscopy, X-ray diffraction and bonding tests. Titanium oxide layer with hierarchical structures consisting of submicron rows of leaf-like embossments and nano-pores was obtained by combining acid etching and anodization processes, which increased the surface roughness of Ti. When heat-treatment temperature was 700 °C and high, CaSiO phase began to crystallize from the bioglass matrix and the crystallinity reached its maximum at 700 °C. During the electrophoretic deposition process, porous bioglass coatings composed of bioglass particles and fibers were deposited on Ti surface. Bioglass coatings with similar hierarchical structure containing submillimeter bioglass beads and microfibers were synthesized on Ti surface by laser fusion. There are no obvious microcracks at the interface of the Ti-coating, which revealed the good bonding between Ti-porcelain. With the laser scanning distance decreased, the bond strength increased accordingly. After only one day immersion in SBF, calcium phosphate began to precipitate on the bioglass coating's surfaces. The thickness of the calcium phosphate precipitation and the amount of microparticles increased with immersion time