Redox-dependent and redox-independent functions of Caenorhabditis elegans thioredoxin 1

Thioredoxins (TRX) are traditionally considered as enzymes catalyzing redox reactions. However, redox-independent functions of thioredoxins have been described in different organisms, although the underlying molecular mechanisms are yet unknown. We report here the characterization of the first generated endogenous redox-inactive thioredoxin in an animal model, the TRX-1 in the nematode Caenorhabditis elegans. We find that TRX-1 dually regulates the formation of an endurance larval stage (dauer) by interacting with the insulin pathway in a redox-independent manner and the cGMP pathway in a redox-dependent manner. Moreover, the requirement of TRX-1 for the extended longevity of worms with compromised insulin signalling or under calorie restriction relies on TRX-1 redox activity. In contrast, the nuclear translocation of the SKN-1 transcription factor and increased LIPS-6 protein levels in the intestine upon trx-1 deficiency are strictly redox-independent. Finally, we identify a novel function of C. elegans TRX-1 in male food-leaving behaviour that is redox-dependent. Taken together, our results position C. elegans as an ideal model to gain mechanistic insight into the redox-independent functions of metazoan thioredoxins, overcoming the limitations imposed by the embryonic lethal phenotypes of thioredoxin mutants in higher organisms.NIH Office of Research Infrastructure P40 OD010440Spanish Ministry of Economy and Competitiveness BFU2015- 64408-PFondo Social Europeo BFU2015- 64408-PNational Institute of Allergy and Infectious Diseases of the National Institutes of Health R01AI07640

Discovery and Characterization of the Polycomb Repressive Complex 1 of C. Elegans

unc-3 encodes the Caenorhabditis elegans homolog of the Olf-1/Early B cell factor family of transcription factors, which in vertebrates regulate development and differentiation of B lymphocytes, adipocytes, and cells of the nervous system. In the first chapter I analyze the role of unc-3 in determining the fates of neurons in ventral nerve cord (VNC). unc-3 mutants are uncoordinated in locomotion. I show that unc-3 represses a VC-like motor neuron program in the VA and VB motor neurons, which in wild-type animals control backwards and forwards locomotion, respectively. Our lab identified a physical interaction between UNC-3 and the C2H2 zinc finger transcription factor PAG-3, the mammalian homologs of which are coexpressed in olfactory epithelium and hematopoietic cells. Our data explain the locomotory defects of unc-3 mutants and suggest that interactions between unc-3 and pag-3 homologs in other species may be functionally important. The second chapter of the thesis is about the analysis of MIG-32 a RING protein similar to some Polycomb proteins that were identified in a yeast two hybrid screen with UNC-3 as bait. The Polycomb repression complex 2 (PRC2) methylates histone H3 lysine 27 at target genes to modify gene expression, and this mark is recognized by PRC1, which ubiquitylates histone H2A. In Caenorhabditis elegans, a complex of the MES-2, MES-3, and MES-6 proteins is functionally analogous to the PRC2 complex, but the functional analog of PRC1, and indeed whether C. elegans has such a complex, has been unclear. I describe here that MIG-32 is a homolog of BMI-1, a core component of PRC1. I also identify SPAT-3A as a homolog of Ring1B, a partner protein of BMI-1 in the PRC1 core complex. Mig-32 and spat-3 mutants have some defects that overlap with those of mes mutants. However, unlike the mes mutants, mig-32 and spat-3 mutants are fertile, despite lacking apparent H2A ubiquitylation. Migration and axon guidance of specific neurons were defective in mig-32 and spat-3 mutants. Our data suggest that mig-32 and spat-3 encode core components of a PRC1-like complex in C. elegans

MIG-32 and SPAT-3A are PRC1 homologs that control neuronal migration in Caenorhabditis elegans

The Polycomb repression complex 2 (PRC2) methylates histone H3 lysine 27 at target genes to modify gene expression, and this mark is recognized by PRC1, which ubiquitylates histone H2A. In Caenorhabditis elegans, a complex of the MES-2, MES-3 and MES-6 proteins is functionally analogous to the PRC2 complex, but the functional analog of PRC1, and indeed whether C. elegans has such a complex, has been unclear. We describe here that MIG-32 and SPAT-3A are functional analogs of PRC1 in C. elegans, where they are required for neuronal migrations and during vulval development. mig-32 and spat-3 mutants are defective in H2A ubiquitylation, and have nervous system defects that partially overlap with those of mes mutants. However, unlike the mes mutants, mig-32 and spat-3 mutants are fertile, suggesting that PRC1 function is not absolutely required in the germline for essential functions of PRC2

Failure behavior of quasi-isotropic laminates with three-pin loaded holes

This paper presents the effect of hole positions on the failure behavior of glass-epoxy laminated composite plates fabricated from stacking sequence [0/90/+/-45]s subjected to a traction force by three-pins. Three different hole distance parameters, namely the ratio of free edge distance to the outer holes/pin diameter (E/D = 1, 2, 3, 4, 5), the ratio of longitudinal distance between the holes/pin diameter (F/D = 2, 4, 6) and the ratio of transverse distance between the parallel holes/pin diameter (G/D = 3, 4, 5) were used to investigate the effects of hole positions on failure load and failure mode. Shear out failure mode which is not the desired mode for a structure occurs around the first and second pin holes very close to the free edge of the specimen (E/D = 1). The other specimens were damaged in bearing mode which is the most desired mode. (C) 2009 Elsevier Ltd. All rights reserved

Comparison of the Effect of Ketamine and Dexmedetomidine Combined with Total Intravenous Anesthesia in Laparoscopic Cholecystectomy Procedures: A Prospective Randomized Controlled Study.

This randomized prospective clinical study aimed to investigate the effects of dexmedetomidine or ketamine administration to total intravenous anesthesia (TIVA) on postoperative analgesia in subjects undergoing elective laparoscopic cholecystectomy procedures. 90 adults, American Society of Anesthesiologists (ASA) physical status 1 and II patients, who underwent elective laparoscopic cholecystectomy procedures were included in the study and randomized into three groups equally. Remifentanil, propofol, and rocuronium infusions were used for TIVA guided by the bispectral index. In group KETA, 10 μg/kg/min ketamine was added to TIVA before surgery, and in group DEX, 0.5 μg/kg/h dexmedetomidine was added to TIVA before surgery. Normal saline infusions were infused in the control group. Postoperative analgesia was provided with intravenous patient-controlled analgesia (PCA) morphine (1 mg bolus morphine, 5 min lockout time). Hemodynamic parameters, scores of visual analogue scale (VAS) for pain, rescue morphine requirements, and side effects such as sedation, nausea, and vomiting were recorded for 48 hours after surgery. Postoperative first analgesic requirement time was longer in group KETA (P < 0.001), and it was longer in group DEX than in the control group (P < 0.001). Pain scores were lower in group KETA and group DEX than in the control group at all corresponding times throughout the 48 h period of observation. Intravenous PCA morphine consumptions were higher in the control group than in group KETA (P < 0.001 for all followed-up times), and they were higher in group DEX than in group KETA (P < 0.001 for all followed-up times). It is concluded that the use of dexmedetomidine or ketamine infusions can be suitable as an additive for TIVA in the intraoperative period. Furthermore, the addition of both drugs to the TIVA protocol may improve postoperative pain relief and decrease opioid consumption

Synergistic Interaction of Paclitaxel and Curcumin with Cyclodextrin Polymer Complexation in Human Cancer Cells

The use of cytotoxic chemotherapic agents is the most common method for the treatment of metastatic cancers. Poor water solubility and low efficiency of chemotherapic agents are among the major hurdles of effective chemotherapy treatments. Curcumin and paclitaxel are well-known chemotherapic agents with poor water solubility and undesired side effects. In this study, a novel drug nanocarrier system was formulated by encapsulating curcumin and paclitaxel in poly­(β-cyclodextrin triazine) (PCDT) for the therapy of four cancer models; ovarian, lung, prostate, and breast cancer. Cell viability and colony formation assays revealed enhanced curcumin cytotoxicity upon complexation. Annexin V apoptotic studies showed that the PCDT complexation improved curcumin induced apoptosis in human ovarian cancer cell lines A2780 and SKOV-3, human nonsmall cell lung carcinoma cell line H1299, and human prostate cancer line DU-145, while no significant effect was observed with paclitaxel/PCDT complexation. The bioactivity of combining curcumin and paclitaxel was also investigated. A synergism was found between curcumin and paclitaxel, particularly when complexed with PCDT on A2780, SKOV-3, and H1299 cancer cell lines

Redox-dependent and redox-independent functions of Caenorhabditis elegans thioredoxin 1

Thioredoxins (TRX) are traditionally considered as enzymes catalyzing redox reactions. However, redox-independent functions of thioredoxins have been described in different organisms, although the underlying molecular mechanisms are yet unknown. We report here the characterization of the first generated endogenous redox-inactive thioredoxin in an animal model, the TRX-1 in the nematode Caenorhabditis elegans. We find that TRX-1 dually regulates the formation of an endurance larval stage (dauer) by interacting with the insulin pathway in a redox-independent manner and the cGMP pathway in a redox-dependent manner. Moreover, the requirement of TRX-1 for the extended longevity of worms with compromised insulin signalling or under calorie restriction relies on TRX-1 redox activity. In contrast, the nuclear translocation of the SKN-1 transcription factor and increased LIPS-6 protein levels in the intestine upon trx-1 deficiency are strictly redox-independent. Finally, we identify a novel function of C. elegans TRX-1 in male food-leaving behaviour that is redox-dependent. Taken together, our results position C. elegans as an ideal model to gain mechanistic insight into the redox-independent functions of metazoan thioredoxins, overcoming the limitations imposed by the embryonic lethal phenotypes of thioredoxin mutants in higher organisms.We thank the Caenorhabditis Genetics Center (CGC), which is funded by NIH Office of Research Infrastructure Programs (P40 OD010440), for providing worm strains and SunyBiotech Corporation for the generation of the trx-1(sgps) strain. We thank Prof. Stefan Taubert for providing the lips-6::gfp reporter strain. AMV was supported by a grant from the Spanish Ministry of Economy and Competitiveness (BFU2015-64408-P), cofinanced by the Fondo Social Europeo (FEDER). DAG was supported by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health under award number R01AI076406. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. AMV is a member of the GENIE and EU-ROS Cost Actions of the European Union

Redox-dependent and redox-independent functions of Caenorhabditis elegans thioredoxin 1.

Thioredoxins (TRX) are traditionally considered as enzymes catalyzing redox reactions. However, redox-independent functions of thioredoxins have been described in different organisms, although the underlying molecular mechanisms are yet unknown. We report here the characterization of the first generated endogenous redox-inactive thioredoxin in an animal model, the TRX-1 in the nematode Caenorhabditis elegans. We find that TRX-1 dually regulates the formation of an endurance larval stage (dauer) by interacting with the insulin pathway in a redox-independent manner and the cGMP pathway in a redox-dependent manner. Moreover, the requirement of TRX-1 for the extended longevity of worms with compromised insulin signalling or under calorie restriction relies on TRX-1 redox activity. In contrast, the nuclear translocation of the SKN-1 transcription factor and increased LIPS-6 protein levels in the intestine upon trx-1 deficiency are strictly redox-independent. Finally, we identify a novel function of C. elegans TRX-1 in male food-leaving behaviour that is redox-dependent. Taken together, our results position C. elegans as an ideal model to gain mechanistic insight into the redox-independent functions of metazoan thioredoxins, overcoming the limitations imposed by the embryonic lethal phenotypes of thioredoxin mutants in higher organisms