This paper presents the synthesis of visible light-responsive ternary nanocomposites composed of cuprous oxide (CuO), tungsten trioxide (WO), and titanium dioxide (TiO) with varying weight percentages (wt.%) of the CuO. The resulting CuO/WO/TiO (CWT) nanocomposites exhibited band gap energy ranging from 2.
View Article and Find Full Text PDFWater pollution has been a prevalent issue globally for some time. Some pollutants are released into the water system without treatment, making the water not suitable for consumption. This problem may lead to more grave problems in the future including the destruction of the ecosystem along with the organisms inhabiting it, and illness and diseases endangering human health.
View Article and Find Full Text PDFTextile dyeing wastewater becomes one of the root causes of environmental pollution. Titanium dioxide (TiO) is one of the photocatalysts that shows prominent organic dye photodegradation ability. In this study, a porous tungsten oxide (WO)/TiO composite was prepared through ultrasonic-assisted solvothermal technique with varying amounts of WO ranging from 0.
View Article and Find Full Text PDFThe DNA damage response helps to maintain genome integrity, suppress tumorigenesis, and mediate the effects of radiotherapy and chemotherapy. Our previous studies have shown that Smad1 is upregulated and activated by Atm in DNA damage response, which can further bind to p53 and promote p53 stabilization. Here we report another aspect of the interplay between p53 and Smad1.
View Article and Find Full Text PDFThe genome is under constant attack by self-produced reactive oxygen species and genotoxic reagents in the environment. Cells have evolved a DNA damage response (DDR) system to sense DNA damage, to halt cell cycle progression and repair the lesions, or to induce apoptosis if encountering irreparable damage. The best studied DDR pathways are the PIKK-p53 and PIKK-Chk1/2.
View Article and Find Full Text PDFCell Mol Biol Lett
September 2013
Signaling at the plasma membrane receptors is generally terminated by some form of feedback regulation, such as endocytosis and/or degradation of the receptors. BMP-Smad1 signaling can also be attenuated by BMP-induced expression of the inhibitory Smads, which are negative regulators of Smad1 transactivation activity and/or BMP antagonists. Here, we report on a novel Smad1 regulation mechanism that occurs in response to the blockade of BMP activity.
View Article and Find Full Text PDFNeural stem cells (NSCs) play essential roles in nervous system development and postnatal neuroregeneration and their deregulation underlies the development of neurodegenerative disorders. Yet how NSC proliferation and differentiation are controlled is not fully understood. Here we present evidence that tumor suppressor p53 regulates NSC proliferation and differentiation via the bone morphogenetic proteins (BMP)-Smad1 pathway and its target gene inhibitor of DNA binding 1 (Id1).
View Article and Find Full Text PDFDefects in stem cell renewal or progenitor cell expansion underlie ageing-related diseases such as osteoporosis. Yet much remains unclear about the mechanisms regulating progenitor expansion. Here we show that the tyrosine kinase c-Abl plays an important role in osteoprogenitor expansion.
View Article and Find Full Text PDFDNA damage and the elicited cellular response underlie the etiology of tumorigenesis and ageing. Yet, how this response integrates inputs from cells' environmental cues remains underexplored. Here we report that the BMP-Smad1 pathway, which is essential for embryonic development and tissue homeostasis, has an important role in the DNA damage response and oncogenesis.
View Article and Find Full Text PDFp53 mediates DNA damage-induced cell-cycle arrest, apoptosis, or senescence, and it is controlled by Mdm2, which mainly ubiquitinates p53 in the nucleus and promotes p53 nuclear export and degradation. By searching for the kinases responsible for Mdm2 S163 phosphorylation under genotoxic stress, we identified S6K1 as a multifaceted regulator of Mdm2. DNA damage activates mTOR-S6K1 through p38alpha MAPK.
View Article and Find Full Text PDFp53-p21-cyclin-dependent kinase and p16(INK4a)-cyclin-dependent kinase pathways have parallel functions in preventing tumorigenesis. In cancer patients, tumor suppressor p53 is frequently inactivated through mutations, whereas p16(INK4a) is silenced through promoter methylation. However, the interaction between these two pathways is less well understood.
View Article and Find Full Text PDFAldose reductase (AR) is implicated in the development of a number of diabetic complications, but the underlying mechanisms remain to be fully elucidated. We performed this study to determine whether and how AR might influence hepatic peroxisome proliferator-activated receptor alpha (PPARalpha) activity and lipid metabolism. Our results in mouse hepatocyte AML12 cells show that AR overexpression caused strong suppression of PPARalpha/delta activity (74%, p < 0.
View Article and Find Full Text PDFActivation of the p53 tumor suppressor upon DNA damage elicits either cell cycle arrest or apoptosis, and the precise mechanism governing cell fate after p53 response has not been well defined. Through genomic analysis, we have identified the ribosomal protein S27-like (RPS27L) as a novel p53 transcriptional target gene. Although RPS27L mRNA levels were consistently induced after diverse p53 activating signals, its change in protein level was stimuli-dependent: it was up-regulated when cells were arrested in response to DNA-damaging agents Adriamycin or VP16 but was down-regulated when cells underwent apoptosis in response to antimetabolite agent 5-fluorouracil.
View Article and Find Full Text PDFTo investigate the underlying causes for aldose reductase deficiency-induced diabetes insipidus, we carried out studies with three genotypic groups of mice. These included wild-type mice, knockout mice, and a newly created bitransgenic line that was homozygous for both the aldose reductase null mutation and an aldose reductase knockin transgene driven by the kidney-specific cadherin promoter to direct transgene expression in the collecting tubule epithelial cells. We found that from early renal developmental stages onward, urine osmolality did not exceed 1,000 mosmol/kgH2O in aldose reductase-deficient mice.
View Article and Find Full Text PDFSodium/myo-inositol cotransporter-1 (SMIT-1) is one of the transporters responsible for importing myo-inositol (MI) into the cells. MI is a precursor for a family of signal transduction molecules, phosphatidylinositol, and its derivatives that regulates many cellular functions. SMIT-1 null mice died soon after birth due to respiratory failure, but neonatal lethality was prevented by prenatal maternal MI supplement.
View Article and Find Full Text PDFThe gastric mucosa is most susceptible to stress that has been shown to induce mucosal damage in humans and animals. This study aims to explore the underlying mechanisms of partial sleep deprivation, as a source of psychophysiological stress, on gastric functions and its effect on mucosal integrity. Sprague-Dawley rats were partially sleep deprived (PSD) for 7 or 14 days by housing inside slowly rotating drums.
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