PRDX1
Peroxiredoxin-1 (EC 1.11.1.24) (Natural killer cell-enhancing factor A) (NKEF-A) (Proliferation-associated gene protein) (PAG) (Thioredoxin peroxidase 2) (Thioredoxin-dependent peroxide reductase 2) (Thioredoxin-dependent peroxiredoxin 1) [PAGA] [PAGB] [TDPX2]
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Recent studies have found vitamin D deficiency promotes fat deposition into the hepatocytes, thus contributing to the development of nonalcoholic fatty liver disease (NAFLD), which is a hepatic manifestation of metabolic syndrome. This study aimed to investigate the potential effects of vitamin D on NAFLD with the involvement of the p53 pathway. Initially, an in vivo high-fat diet (HFD)-induced NAFLD mouse model was established. Then the HFD-induced NAFLD mice were treated with vitamin D. Next, the serum levels of TNF-α, GSH-px and malondialdehyde (MDA) were assessed using ELISA and ROS content was evaluated by flow cytometry, followed by the measurement of expression of Duox1, Duox2, SOD1, SOD2, PRDX1 I, ACC, SREBP1c, MTTP, PPARα, p53, p21 and p16 using RT-qPCR and Western blot analysis. Positive expression of FAS and FASL proteins was measured using immunohistochemistry. TUNEL and Senescence-associated β-galactosidase (SA-β-Gal) staining were subsequently conducted to assess the senescence and apoptosis of hepatocytes. HFD-induced mice treated with vitamin D presented with significantly increased GSH-px levels, as well as protein expression of SOD1, SOD2, PRDX1, MTTP and PPARα, but decreased MDA and ROS levels, expression of Duox1, Duox2, ACC, SREBP1c, p53, p21 and p16, positive expression of FAS and FASL proteins as well as impaired senescence and apoptosis of hepatocytes. Active vitamin D supplementation could potentially impede hepatocyte senescence and apoptosis via suppression of the p53 pathway, thus preventing the progression of NAFLD. Our study provides available evidence on the potential clinical utility of vitamin D supplementation in NAFLD.
MeSH Terms
- Animals
- Apoptosis
- Cellular Senescence
- Diet, High-Fat
- Dietary Supplements
- Fas Ligand Protein
- Hepatocytes
- Metabolic Networks and Pathways
- Mice, Knockout
- Non-alcoholic Fatty Liver Disease
- Oxidative Stress
- Proteins
- Steroid Hydroxylases
- Tumor Suppressor Protein p53
- Vitamin D
- fas Receptor
Keywords
- Active vitamin D
- Apoptosis
- Nonalcoholic fatty liver disease
- Oxidative stress
- Senescence
- p53 pathway
Telomerase counteracts telomere shortening and cellular senescence in germ, stem, and cancer cells by adding repetitive DNA sequences to the ends of chromosomes. Telomeres are susceptible to damage by reactive oxygen species (ROS), but the consequences of oxidation of telomeres on telomere length and the mechanisms that protect from ROS-mediated telomere damage are not well understood. In particular, 8-oxoguanine nucleotides at 3' ends of telomeric substrates inhibit telomerase in vitro, whereas, at internal positions, they suppress G-quadruplex formation and were therefore proposed to promote telomerase activity. Here, we disrupt the peroxiredoxin 1 ([i]PRDX1[/i]) and 7,8-dihydro-8-oxoguanine triphosphatase ([i]MTH1[/i]) genes in cancer cells and demonstrate that PRDX1 and MTH1 cooperate to prevent accumulation of oxidized guanine in the genome. Concomitant disruption of [i]PRDX1[/i] and [i]MTH1[/i] leads to ROS concentration-dependent continuous shortening of telomeres, which is due to efficient inhibition of telomere extension by telomerase. Our results identify antioxidant systems that are required to protect telomeres from oxidation and are necessary to allow telomere maintenance by telomerase conferring immortality to cancer cells.
MeSH Terms
- DNA Damage
- DNA Repair Enzymes
- Enzyme Activation
- Gene Knockout Techniques
- Genome
- Guanine
- HCT116 Cells
- Humans
- Oxidation-Reduction
- Oxidative Stress
- Peroxiredoxins
- Phosphoric Monoester Hydrolases
- Reactive Oxygen Species
- Telomerase
- Telomere Homeostasis
- Telomere Shortening
Keywords
- MTH1
- PRDX1
- aging
- cellular senescence
- oxidative stress
- telomerase
- telomeres
Follicular fluid (FF) accumulates in the antrum of the ovarian follicle. In addition, FF provides the microenvironment for oocyte development, oocyte maturation and competence, which are acquired during follicular development. Superstimulatory treatment of 1-month-old lambs can achieve synchronous development of numerous growing follicles. However, these growing follicles are unable to completely mature and ovulate. Furthermore, the oocytes exhibit lower competence compared with those of ewes. In this study, we utilized an isobaric tag for relative and absolute quantification (iTRAQ)-based proteomics analysis and compare protein composition between pre-pubertal and adult superstimulated follicle FF in sheep. In total, 243 differentially expressed proteins were identified, including 155 downregulated and 88 upregulated between lamb and ewe. Gene ontology (GO) and KEGG pathway analysis indicated that the differentially expressed proteins are involved in signal transduction, anatomical structure development, stress response, metabolic pathways, and the complement and coagulation cascades. Many of the proteins known to affect follicle development were observed in lower abundance in FF of lamb (e.g. ADAMTS9, CD14, CTNNB1, FST, GCLC, HSPG2, IGFBP2, IGFBP6, INHBA, PRL, PAPPA, POSTN, PRDX1, SERPINA1, SOD3, STC1, VEGFC, etc.). However, a higher abundance was observed for proteasome proteins. Inadequate amounts of these proteins in FF may be lead to the unique characteristics of follicular development in lamb. These differentially expressed proteins illuminate the age-dependent changes in protein expression in the follicle microenvironment.
MeSH Terms
- Aging
- Animals
- Female
- Follicle Stimulating Hormone
- Follicular Fluid
- Gene Ontology
- Ovarian Follicle
- Proteomics
- Sexual Maturation
- Sheep, Domestic
Keywords
- follicular fluid
- lamb
- proteome
- quantitative proteomic
- superstimulation
Pin1 isomerizes the phosphorylated Ser/Thr-Pro peptide bonds and regulates the functions of its binding proteins by inducing conformational changes. Involvement of Pin1 in the aging process has been suggested based on the phenotype of Pin1-knockout mice and its interaction with lifespan regulator protein, p66 (Shc) . In this study, we utilize a proteomic approach and identify peroxiredoxin 1 (PRDX1), another regulator of aging, as a novel Pin1 binding protein. Pin1 binds to PRDX1 through interacting with the phospho-Thr ( 90) -Pro ( 91) motif of PRDX1, and this interaction is abolished when the Thr ( 90) of PRDX1 is mutated. The Pin1 binding motif, Thr-Pro, is conserved in the 2-Cys PRDXs, PRDX1-4 and the interactions between Pin1 and PRDX2-4 are also demonstrated. An increase in hydrogen peroxide buildup and a decrease in the peroxidase activity of 2-Cys PRDXs were observed in Pin1 (-/-) mouse embryonic fibroblasts (MEFs), with the activity of PRDXs restored when Pin1 was re-introduced into the cells. Phosphorylation of PRDX1 at Thr ( 90) has been shown to inhibit its peroxidase activity; however, how exactly the activity of PRDX1 is regulated by phosphorylation still remains unknown. Here, we demonstrate that Pin1 facilitates the protein phosphatase 2A-mediated dephosphorylation of PRDX1, which helps to explain the accumulation of the inactive phosphorylated form of PRDX1 in Pin1 (-/-) MEFs. Collectively, we identify Pin1 as a novel PRDX1 binding protein and propose a mechanism for Pin1 in regulating the metabolism of reactive oxygen species in cells.
MeSH Terms
- Aging
- Animals
- HEK293 Cells
- HeLa Cells
- Humans
- Hydrogen Peroxide
- Mice
- NIMA-Interacting Peptidylprolyl Isomerase
- Oxidation-Reduction
- Peptidylprolyl Isomerase
- Peroxiredoxins
- Phosphorylation
- Protein Binding
- Protein Phosphatase 2
- Reactive Oxygen Species
- Transcription Factors
Keywords
- PP2A
- PRDX1
- Pin1
- aging and reactive oxygen species
- p66Shc
- phosphorylation