20 research outputs found
Identification and quantification of a novel nitrate-reducing community in sediments of SuquĂa River basin along a nitrate gradient
We evaluated the molecular diversity of narG gene from SuquĂa River sediments to assess the impact of the nitrate concentration and water quality on the composition and structure of the nitrate-reducing bacterial community. To this aim, a library of one of the six monitoring stations corresponding to the highest nitrate concentration was constructed and 118 narG clones were screened. Nucleotide sequences were associated to narG gene from alpha-, beta-, delta-, gammaproteobacteria and Thermus thermophilus. Remarkably, 18% of clones contained narG genes with less than 69% similarity to narG sequences available in databases. Thus, indicating the presence of nitrate-reducing bacteria with novel narG genes, which were quantified by real-time PCR. Results show a variable number of narG copies, ranging from less than 1.0 Ă— 102 to 5.0 Ă— 104 copies per ng of DNA, which were associated with a decreased water quality index monitored along the basin at different times.Fil: Reyna, Luciana. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; ArgentinaFil: Wunderlin, Daniel Alberto. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; ArgentinaFil: Genti de Raimondi, Susana. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentin
Placental oxidative status in rural residents environmentally exposed to organophosphates
The impact of environmental organophosphate pesticide exposure on the placenta oxidative status was assessed. Placental samples were collected from women residing in an agricultural area during pesticide pulverization period, non-pulverization period and from control group. Carboxylesterase activity was significantly decreased in pulverization period group. Enzymatic and non-enzymatic defense system, the oxidative stress biomarkers and the nuclear factor erythroid 2-related factor levels showed no differences among groups. However, in the pulverization period group, an inverse association between catalase activity and placental index, a useful metric for estimating placental inefficiency, was found. This result suggests that catalase may serve as a potential placental biomarker of susceptibility to pesticides. Further studies designed from a gene-environment perspective are needed.Fil: Chiapella, Graciela. Universidad Nacional del Comahue. Facultad de Medicina; ArgentinaFil: Genti de Raimondi, Susana. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Magnarelli, Gladis Griselda. Universidad Nacional del Comahue. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentin
Chlorpyrifos induces endoplasmic reticulum stress in JEG-3 cells
Chlorpyrifos (CPF) is an organophosphorous pesticide widely used in agricultural, industrial, and household applications. We have previously shown that JEG-3 cells are able to attenuate the oxidative stress induced by CPF through the adaptive activation of the Nrf2/ARE pathway. Considering that there is a relationship between oxidative stress and endoplasmic reticulum stress (ER), herein we investigated whether CPF also induces ER stress in JEG-3 cells. Cells were exposed to 50 ÎĽM or 100 ÎĽM CPF during 24 h in conditions where cell viability was not altered. Western blot and PCR assays were used to explore the protein and mRNA levels of ER stress biomarkers, respectively. CPF induced an increase of the typical ER stress-related proteins, such as GRP78/BiP and IRE1α, a sensor for the unfolded protein response, as well as in phospho-eIF2α and XBP1 mRNA splicing. Additionally, CPF led to a decrease in p53 protein expression. The downregulation of p53 levels induced by CPF was partially blocked when cells were exposed to CPF in the presence of the proteasome inhibitor MG132. Altogether, these findings point out that CPF induces ER stress in JEG-3 cells; however these cells are able to attenuate it downregulating the levels of the pro-apoptotic protein p53.Fil: Reyna, Luciana. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Flores MartĂn, JĂ©sica BelĂ©n. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; ArgentinaFil: Ridano, Magali Evelin. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Panzetta-Dutari, Graciela Maria del Valle. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; ArgentinaFil: Genti de Raimondi, Susana. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentin
The lipid transfer protein StarD7: structure, function, and regulation
The steroidogenic acute regulatory (StAR) protein-related lipid transfer (START) domain proteins constitute a family of evolutionarily conserved and widely expressed proteins that have been implicated in lipid transport, metabolism, and signaling. The 15 well-characterized mammalian START domain-containing proteins are grouped into six subfamilies. The START domain containing 7 mRNA encodes StarD7, a member of the StarD2/phosphatidylcholine transfer protein (PCTP) subfamily, which was first identified as a gene overexpressed in a choriocarcinoma cell line. Recent studies show that the StarD7 protein facilitates the delivery of phosphatidylcholine to the mitochondria. This review summarizes the latest advances in StarD7 research, focusing on the structural and biochemical features, protein-lipid interactions, and mechanisms that regulate StarD7 expression. The implications of the role of StarD7 in cell proliferation, migration, and differentiation are also discussed.Fil: Flores MartĂn, JĂ©sica BelĂ©n. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones En BioquĂmica ClĂnica E InmunologĂa; Argentina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; ArgentinaFil: Rena, Viviana Celeste del Valle. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones En BioquĂmica ClĂnica E InmunologĂa; Argentina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; ArgentinaFil: Angeletti, Sofia Claudia. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Panzetta-Dutari, Graciela Maria del Valle. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones En BioquĂmica ClĂnica E InmunologĂa; Argentina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; ArgentinaFil: Genti de Raimondi, Susana. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones En BioquĂmica ClĂnica E InmunologĂa; Argentina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; Argentin
Expression and Transcriptional Regulation of Individual Pregnancy-specific Glycoprotein Genes in Differentiating Trophoblast Cells
Human pregnancy-specific glycoproteins (PSGs), encoded by eleven highly conserved genes, are the major placental polypeptides. Low PSG levels in maternal circulation have been associated with complicated pregnancies. However, expression of each PSG gene and their regulation during cytotrophoblast cell differentiation remain poorly explored. Herein, we analyze the expression of five PSG genes and demonstrate that they are almost undetectable in undifferentiated trophoblast, but are all transcribed in differentiated cells. Among them, PSG1, PSG3 and PSG5 genes achieve high mRNA levels while PSG7 and PSG9 are poorly expressed. In addition, total PSG proteins and transcripts markedly increase during trophoblast differentiation, preceding morphological syncytialization and βhCG expression. The 5′ regulatory region contributes to the transcriptional control of PSG gene induction in trophoblast cells undergoing differentiation. This responsive region in PSG3 maps within a 130 bp promoter sequence, which overlaps the transcription start site and requires a functional Retinoic Acid Responsive Element (RARE) and a GA-binding protein (GABP) consensus site for basal and differentiation-dependent promoter activity, respectively. Present findings provide novel data for understanding the control of PSG gene expression and demonstrate that their proteins and transcripts represent early markers of trophoblast differentiation.Fil: Camolotto, Soledad Andrea. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; ArgentinaFil: Racca, Ana Cristina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; ArgentinaFil: Rena, Viviana Celeste del Valle. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; ArgentinaFil: Nores, Rodrigo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; ArgentinaFil: Patrito, Luis Clemente. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; ArgentinaFil: Genti de Raimondi, Susana. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; ArgentinaFil: Panzetta-Dutari, Graciela Maria del Valle. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Departamento de BioquĂmica ClĂnica; Argentin
Environmental factors associated with heterotrophic nitrogen-fixing bacteria in water, sediment, and riparian soil of SuquĂa River
In this study we investigated the environmental factors associated with biological nitrogen (N) fixation (BNF) in water, sediments, and riparian soil along a polluted river (SuquĂa River of CĂłrdoba, Argentina). Here, we screened heterotrophic nitrogen-fixing bacteria and assessed the magnitude of BNF at different sites of SuquĂa River. To this aim, samples of the three habitats (riparian soil, water, and sediment) were collected from five polluted sites and one reference site during low and high flow water periods. In all samples the abundance of N-fixing bacteria was evaluated in solid nitrogen-free medium and the biological N fixation was measured by nitrogenase (Nase) enzyme activity using the acetylene reduction method. To identify the heterotrophic N-fixing taxa DNA of nine cultures isolated from sites with different Nase enzyme activity was extracted and the 16S rRNA gene was amplified and sequenced. In addition, the ammonia and organic carbon (C) content in all samples, the dissolved O2 concentration in water, and the water content in riparian soil were measured. The N-fixing bacteria were detected in all study sites and habitats. The abundance of them correlated significantly with organic C content in sediment, and with water and organic C contents in riparian soil, whereas in water a negative correlation with dissolved O2 was observed. In addition, the water and sediment Nase enzyme activity varied among sites during low flow period presenting significant correlation with ammonia and organic C contents in sediment. The identified taxonomic groups in the SuquĂa River are related to Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Actinobacteria although the N-fixing capacity of them was not established. Altogether these findings demonstrate that BNF occurs in all habitats of SuquĂa River, being in sediments influenced mainly by the higher organic C present in the most polluted sites, while in riparian soil the organic C and water contents were the major abiotic factors that control the abundance of N-fixing bacteria. In SuquĂa River water the density of N-fixing bacteria were associated with low dissolved O2 concentration. These data suggest that the BNF in SuquĂa River is a complex process that depends on numerous environmental factors that act together.Fil: Merlo, Carolina. Universidad Nacional de CĂłrdoba. Facultad de Ciencias Agropecuarias; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Reyna, Luciana. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Abril, Adriana. Universidad Nacional de CĂłrdoba. Facultad de Ciencias Agropecuarias; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: AmĂ©, MarĂa Valeria. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Genti de Raimondi, Susana. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentin
Regulation of testosterone degradation in Comamonas testosteroni
Recently, we have identified a gene encoding a LuxR-type factor, TeiR (Testosterone-inducible Regulator), which positively regulates steroid degradation in Comamonas testosteroni. Herein, we demonstrate that TeiR interacts in vivo with steroid catabolic gene promoters. The presence of testosterone induces a significant TeiR protein increase at the early logarithmic phase of growth. Interestingly, it is not until the early stationary phase where the activation of a steroid-inducible gene promoter is observed, indicating that testosterone might not be the true inductor of the steroid degradation pathway. In addition, β-galactosidase expression driven by a testosterone-inducible promoter is prematurely activated in cells cultured in medium supplemented with ethyl acetate extracts obtained from the early stationary phase cell-free supernatants of C. testosteroni grown in presence of testosterone. Complementation experiments of C. testosteroni wild type performed with teiR deletion constructs indicate that extra-copies of deleted-TeiR exert a dominant negative effect on the wild-type TeiR protein. While, when C. testosteroni teiR mutants were used to carry out complementation assays only the full length gene can overcome the teiR mutant phenotype. Altogether these findings indicate that TeiR regulates steroid catabolic genes interacting with their promoters and suggest that this interaction requires the presence of a testosterone-derived metabolite to induce the system.Fil: Linares, Mauricio Adrián. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Pruneda Paz, Jose Luis Pablo. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas; ArgentinaFil: Reyna, Luciana. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Genti de Raimondi, Susana. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentin
StarD7 gene expression in trophoblast cells: Contribution of SF-1 and Wnt-β-catenin signaling
Steroidogenic acute regulatory protein-related lipid transfer domain containing 7 (StarD7) is a poorly characterized member of the steroidogenic acute regulatory protein-related lipid transfer proteins, up-regulated in JEG-3 cells, involved in intracellular transport and metabolism of lipids. Previous studies dealing with the mechanisms underlying the human StarD7 gene expression led us to define the cis-acting regulatory sequences in the StarD7 promoter using as a model JEG-3 cells. These include a functional T cell-specific transcription factor 4 (TCF4) site involved in Wnt-(3-catenin signaling. To understand these mechanisms in more depth, we examined the steroidogenic factor 1 (SF-1) contribution to StarD7 expression. Cotransfection experiments in JEG-3 cells point out that the StarD7 promoter is activated by SF-1, and this effect is increased by forskolin. EMSA using JEG-3 nuclear proteins demonstrated that SF-1 binds to the StarD7 promoter. Additionally, chromatin immunoprecipitation analysis indicated that SF-1 and β-catenin are bound in vivo to the StarD7 promoter. Reporter gene assays in combination with mutations in the SF-1 and TCF4 binding sites revealed that the StarD7 promoter is synergistically activated by SF-1 and β-catenin and that the TCF4 binding site (-614/-608) plays an important role in this activation. SF-1 amino acid mutations involved in the physical interaction with β-catenin abolished this activation; thus demonstrating that the contact between the two proteins is necessary for an efficient StarD7 transcriptional induction. Finally, these data suggest that β-catenin could function as a bridge between SF-1 and TCF4 forming a ternary complex, which would stimulate StarD7 expression. The SF-1 and β-catenin pathway convergence on StarD7 expression may have important implications in the phospholipid uptake and transport, contributing to the normal trophoblast development.Fil: Rena, Viviana Celeste del Valle. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Flores MartĂn, JĂ©sica BelĂ©n. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Angeletti, Sofia Claudia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Panzetta-Dutari, Graciela Maria del Valle. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Genti de Raimondi, Susana. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentin
StarD7 behaves as a fusogenic protein in model and cell membrane bilayers
StarD7 is a surface active protein, structurally related with the START lipid transport family. So, the present work was aimed at elucidating a potential mechanism of action for StarD7 that could be related to its interaction with a lipid–membrane interface. We applied an assay based on the fluorescence de-quenching of BD-HPC-labeled DMPC–DMPS 4:1 mol/mol SUVs (donor liposomes) induced by the dilution with non-labeled DMPC–DMPS 4:1 mol/mol LUVs (acceptor liposomes). Recombinant StarD7 accelerated the dilution of BD-HPC in a concentration-dependent manner. This result could have been explained by either a bilayer fusion or monomeric transport of the labeled lipid between donor and acceptor liposomes. Further experiments (fluorescence energy transfer between DPH-HPC/BD-HPC, liposome size distribution analysis by dynamic light scattering, and the multinuclear giant cell formation induced by recombinant StarD7) strongly indicated that bilayer fusion was the mechanism responsible for the StarD7-induced lipid dilution. The efficiency of lipid dilution was dependent on StarD7 electrostatic interactions with the lipid–water interface, as shown by the pH- and salt-induced modulation. Moreover, this process was favored by phosphatidylethanolamine which is known to stabilize non-lamellar phases considered as intermediary in the fusion process. Altogether these findings allow postulate StarD7 as a fusogenic protein.Fil: Angeletti, Sofia Claudia. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas; ArgentinaFil: Sanchez, Julieta Maria. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto de Investigaciones BiolĂłgicas y TecnolĂłgicas. Universidad Nacional de CĂłrdoba. Facultad de Ciencias Exactas, FĂsicas y Naturales. Instituto de Investigaciones BiolĂłgicas y TecnolĂłgicas; ArgentinaFil: Chamley, Larry W.. The University of Auckland; Nueva ZelandaFil: Genti de Raimondi, Susana. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Perillo, Maria Angelica. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto de Investigaciones BiolĂłgicas y TecnolĂłgicas. Universidad Nacional de CĂłrdoba. Facultad de Ciencias Exactas, FĂsicas y Naturales. Instituto de Investigaciones BiolĂłgicas y TecnolĂłgicas; Argentin
Suppression of StarD7 promotes endoplasmic reticulum stress and induces ROS production
StarD7 is an intracellular lipid transport protein identified as up-regulated in the choriocarcinoma JEG-3 cell line. StarD7 facilitates the delivery of phosphatidylcholine (PC) to the mitochondria, and StarD7 knockdown causes a reduction in phospholipid synthesis. Since inhibition of PC synthesis may lead to endoplasmic reticulum (ER) stress we hypothesized that StarD7 may be involved in maintaining cell homeostasis. Here, we examined the effect of StarD7 silencing on ER stress response and on the levels of reactive oxygen species (ROS) in the human hepatoma cell line HepG2. StarD7 knockdown induced alterations in mitochondria and ER morphology. These changes were accompanied with an ER stress response as determined by increased expression of inositol-requiring enzyme 1α (IRE1α), calnexin, glucose regulated protein 78/immunoglobulin heavy chain-binding protein (Grp78/BiP), protein kinase-like ER kinase (PERK) as well as the phosphorylated eukaryotic translation initiation factor 2, subunit 1α (p-eIF2α). Additionally, a downregulation of the tumor suppressor p53 by a degradation mechanism was observed in StarD7 siRNA cells. Furthermore, StarD7 silencing induced ROS generation and reduced cell viability after H2O2 exposure. Decreased expression of StarD7 was associated to increased levels of the heme oxygenase-1 (HO-1) and catalase enzymes as well as in catalase enzymatic activity. Finally, no changes in levels of autophagy and apoptosis markers were observed in StarD7 siRNA treated cells respect to control cells. Taken together, these results indicate that StarD7 contributes to modulate cellular redox homeostasis.Fil: Flores-MartĂn, Jesica. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Reyna, Luciana. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Ridano, Magali Evelin. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Panzetta-Dutari, Graciela Maria del Valle. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; ArgentinaFil: Genti de Raimondi, Susana. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentin