Project description:RNA-seq analysis was performed in samples from WT and NOX4 Knock-out mice after two-thirds Partial Hepatectomy (PH). Transcriptomic analysis through RNA-seq revealed significant changes mainly 24 hours after PH in NOX4-/- mice and support a relevant role for Myc in a node of regulation of proliferation-related genes.
Project description:NADPH oxidases are the only know enzyme family that has reactive oxygen species (ROS, e.g. superoxide and hydrogen peroxide) as their main metabolic product. They are therefore a prima candidate gene family to define a molecular source for ROS in physiology and pathophysiology. The type 4 NADPH oxidase (NOX4) is the most abundant isoform with the highest basal expression levels.The Nox4 knockout mouse was designed using a cre/lox recombination technique which allows to create either constitutive (type III recombination) and conditional (type I recombination) knockout alleles.
Project description:PDAC cells acquire metabolic changes that augment NADPH production and cytosolic redox homeostasis. Here we show that high NADPH levels drive activity of NADPH oxidase 4 (NOX4) expressed in the endoplasmic reticulum (ER) membrane. NOX4 produces H2O2 metabolized by Peroxiredoxin 4 (PRDX4) in the ER lumen. Using functional genomics and subsequent in vitro and in vivo validations, we find that PDAC cell lines with high NADPH levels are dependent on PRDX4 for their growth and survival. PRDX4 addiction is associated with increased reactive oxygen species, a DNA-PKcs-governed DNA damage response and radiosensitivity, which can be rescued by depletion of NOX4 or NADPH. As such, this study has identified NOX4 as a protein which paradoxically converts the reducing power of the cytosol to an ER-specific oxidative stress vulnerability in PDAC that may be therapeutically exploited by targeting PRDX4.
Project description:NADPH oxidases are the only know enzyme family that has reactive oxygen species (ROS, e.g. superoxide and hydrogen peroxide) as their main metabolic product. They are therefore a prima candidate gene family to define a molecular source for ROS in physiology and pathophysiology. The type 4 NADPH oxidase (NOX4) is the most abundant isoform with the highest basal expression levels.The Nox4 knockout mouse was designed using a cre/lox recombination technique which allows to create either constitutive (type III recombination) and conditional (type I recombination) knockout alleles. cDNA microarray experiments of brain, kidney, muscle and pancreas of four male mutant mice versus a RNA pool of four male wild type mice. For each animal two technical replicates were performed including a dye swap experiment. All animals with the same age of 17 weeks on a C57BL/6 background.
Project description:Mycobacterium tuberculosis’success as a pathogen comes from itsability to evade degradation by macrophages. Normally macro-phages clear microorganisms that activate pathogen-recognitionreceptors (PRRs) through a lysosomal-trafficking pathway called“LC3-associated phagocytosis”(LAP). AlthoughM.tuberculosisac-tivates numerous PRRs, for reasons that are poorly understoodLAP does not substantially contribute toM.tuberculosiscontrol.LAP depends upon reactive oxygen species (ROS) generated byNADPH oxidase, butM.tuberculosisfails to generate a robustoxidative response. Here, we show that CpsA, a LytR-CpsA-Psr(LCP) domain-containing protein, is required forM.tuberculosisto evade killing by NADPH oxidase and LAP. Unlike phagosomescontaining wild-type bacilli, phagosomes containing theΔcpsAmutant recruited NADPH oxidase, produced ROS, associated withLC3, and matured into antibacterial lysosomes. Moreover, CpsAwas sufficient to impair NADPH oxidase recruitment to fungal par-ticles that are normally cleared by LAP. Intracellular survival of theΔcpsAmutant was largely restored in macrophages missing LAPcomponents (Nox2,Rubicon,Beclin,Atg5,Atg7,orAtg16L1) butnot in macrophages defective in a related, canonical autophagypathway (Atg14,Ulk1,orcGAS). TheΔcpsAmutant was highlyimpaired in vivo, and its growth was partially restored in micedeficient in NADPH oxidase,Atg5,orAtg7, demonstrating thatCpsA makes a significant contribution to the resistance ofM.tu-berculosisto NADPH oxidase and LC3 trafficking in vivo. Overall,our findings reveal an essential role of CpsA in innate immuneevasion and suggest that LCP proteins have functions beyond theirpreviously known role in cell-wall metabolism.
Project description:Differentiation of fibroblasts to myofibroblasts is governed by the transforming growth factor beta (TGF-β) through a mechanism involving redox signaling and generation of reactive oxygen species (ROS). Myofibroblasts synthesize proteins of the extracellular matrix and display a contractile phenotype. Myofibroblasts are predominant contributors of wound healing and several pathological states, including fibrotic diseases and cancer. Inhibition of the ROS-generating enzyme NADPH oxidase 4 (NOX4) has been proposed to mitigate fibroblast to myofibroblast differentiation and to offer a therapeutic option for the treatment of fibrotic diseases. In this study, we addressed the role of NOX4 in physiological wound healing and in TGF-β-induced myofibroblast differentiation. We explored the phenotypic changes induced by TGF-β in primary skin fibroblasts isolated from Nox4-deficient mice by immunofluorescence, Western blotting and RNA sequencing. Mice deficient for Cyba, the gene coding for p22phox, a key subunit of NOX4 were used for confirmatory experiments as well as human primary skin fibroblasts. In vivo, the wound healing was similar in wild-type and Nox4-deficient mice. In vitro, despite a strong upregulation following TGF-β treatment, Nox4 did not influence skin myofibroblast differentiation. Nevertheless, up-regulation of the mitochondrial protein Ucp2 and the stress-response protein Hddc3, as well as down-regulation of Islr were observed in Nox4-deficient fibroblasts. Altogether, we provide extensive evidence challenging a profibrotic role of NOX4 in skin fibroblasts and show that Nox4 regulates Ucp2 and Hddc3 expression, suggesting the presence of a so far undescribed redox crosstalk between NOX4 and redox homeostasis in fibroblasts.
Project description:NADPH dependent phagocytic oxidase, by producing hydroxyradicals such as hydrogen peroxide, is essential for host defense against Salmonella infection. We used gene array analysis to identify Salmonella enterica serovar Typhimurium genes regulated by NADPH dependent phagocytic oxidase intracellularly in comparison to those expressed in vitro by hydrogen peroxide.
Project description:Small nucleolar RNAs (snoRNAs) guide nucleotide modifications of cellular RNAs in the nucleus. We have previously shown that box C/D snoRNAs from the Rpl13a locus are unexpected mediators of physiologic oxidative stress, independent of their predicted ribosomal RNA modifications. Here, we demonstrate that oxidative stress induced by doxorubicin causes rapid cytoplasmic accumulation of the Rpl13a snoRNAs through a mechanism that requires superoxide and a nuclear splice variant of NADPH oxidase. RNA-sequencing analysis reveals that box C/D snoRNAs as a class are present in the cytoplasm, where their levels are dynamically regulated by NADPH oxidase. These findings suggest that snoRNAs may orchestrate the response to environmental stress through molecular interactions outside of the nucleus.
Project description:Within the family of NADPH oxidases, Nox4 is unique as it is predominantly localized in the endoplasmic reticulum, has constitutive activity and generates H2O2. We hypothesize that these features are consequences of a so far unidentified Nox4-interacting protein. Interacting proteins were screened by quantitative SILAC-Co-immunoprecipitation in HEK293 cells stably overexpressing Nox4. By this technique, several interacting proteins were identified with calnexin showing the most robust interaction.