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  • 1
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    Online Resource
    Protein expression profiling of lens epithelial cells from Prdx6-depleted mice and their vulnerability to UV radiation exposure
    American Physiological Society ; 2010
    In:  American Journal of Physiology-Cell Physiology Vol. 298, No. 2 ( 2010-02), p. C342-C354
    Details
    In: American Journal of Physiology-Cell Physiology, American Physiological Society, Vol. 298, No. 2 ( 2010-02), p. C342-C354
    Abstract: Oxidative stress is one of the causative factors in progression and etiology of age-related cataract. Peroxiredoxin 6 (Prdx6), a savior for cells from internal or external environmental stresses, plays a role in cellular signaling by detoxifying reactive oxygen species (ROS) and thereby controlling gene regulation. Using targeted inactivation of the Prdx6 gene, we show that Prdx6-deficient lens epithelial cells (LECs) are more vulnerable to UV-triggered cell death, a major cause of skin disorders including cataractogenesis, and these cells display abnormal protein profiles. PRDX6-depleted LECs showed phenotypic changes and formed lentoid body, a characteristic of terminal cell differentiation and epithelial-mesenchymal transition. Prdx6 −/− LECs exposed to UV-B showed higher ROS expression and were prone to apoptosis compared with wild-type LECs, underscoring a protective role for Prdx6. Comparative proteomic analysis using fluorescence-based difference gel electrophoresis along with mass spectrometry and database searching revealed a total of 13 proteins that were differentially expressed in Prdx6 −/− cells. Six proteins were upregulated, whereas expression of seven proteins was decreased compared with Prdx6 +/+ LECs. Among the cytoskeleton-associated proteins that were highly expressed in Prdx6-deficient LECs was tropomyosin (Tm)2β. Protein blot and real-time PCR validated dramatic increase of Tm2β and Tm1α expression in these cells. Importantly, Prdx6 +/+ LECs showed a similar pattern of Tm2β protein expression after transforming growth factor (TGF)-β or H 2 O 2 treatment. An extrinsic supply of PRDX6 could restore Tm2β expression, demonstrating that PRDX6 may attenuate adverse signaling in cells and thereby maintain cellular homeostasis. Exploring redox-proteomics ( Prdx6 −/− ) and characterization and identification of abnormally expressed proteins and their attenuation by PRDX6 delivery should provide a basis for development of novel therapeutic interventions to postpone ROS-mediated abnormal signaling deleterious to cells or tissues.
    Type of Medium: Online Resource
    ISSN: 0363-6143 , 1522-1563
    URL: Article
    DOI: 10.1152/ajpcell.00336.2009
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2010
    detail.hit.zdb_id: 1477334-X
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  • 2
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    Online Resource
    Curcumin abates hypoxia-induced oxidative stress based-ER stress-mediated cell death in mouse hippocampal cells (HT22) by controlling Prdx6 and NF-κB regulation
    American Physiological Society ; 2013
    In:  American Journal of Physiology-Cell Physiology Vol. 304, No. 7 ( 2013-04-01), p. C636-C655
    Details
    In: American Journal of Physiology-Cell Physiology, American Physiological Society, Vol. 304, No. 7 ( 2013-04-01), p. C636-C655
    Abstract: Oxidative stress and endoplasmic reticulum (ER) stress are emerging as crucial events in the etiopathology of many neurodegenerative diseases. While the neuroprotective contributions of the dietary compound curcumin has been recognized, the molecular mechanisms underlying curcumin's neuroprotection under oxidative and ER stresses remains elusive. Herein, we show that curcumin protects HT22 from oxidative and ER stresses evoked by the hypoxia (1% O 2 or CoCl 2 treatment) by enhancing peroxiredoxin 6 (Prdx6) expression. Cells exposed to CoCl 2 displayed reduced expression of Prdx6 with higher reactive oxygen species (ROS) expression and activation of NF-κB with IκB phosphorylation. When NF-κB activity was blocked by using SN50, an inhibitor of NF-κB, or cells treated with curcumin, the repression of Prdx6 expression was restored, suggesting the involvement of NF-κB in modulating Prdx6 expression. These cells were enriched with an accumulation of ER stress proteins, C/EBP homologous protein (CHOP), GRP/78, and calreticulin, and had activated states of caspases 12, 9, and 3. Reinforced expression of Prdx6 in HT22 cells by curcumin reestablished survival signaling by reducing propagation of ROS and blunting ER stress signaling. Intriguingly, knockdown of Prdx6 by antisense revealed that loss of Prdx6 contributed to cell death by sustaining enhanced levels of ER stress-responsive proapoptotic proteins, which was due to elevated ROS production, suggesting that Prdx6 deficiency is a cause of initiation of ROS-mediated ER stress-induced apoptosis. We propose that using curcumin to reinforce the naturally occurring Prdx6 expression and attenuate ROS-based ER stress and NF-κB-mediated aberrant signaling improves cell survival and may provide an avenue to treat and/or postpone diseases associated with ROS or ER stress.
    Type of Medium: Online Resource
    ISSN: 0363-6143 , 1522-1563
    URL: Article
    DOI: 10.1152/ajpcell.00345.2012
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2013
    detail.hit.zdb_id: 1477334-X
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  • 3
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    Online Resource
    Delivery of a protein transduction domain-mediated Prdx6 protein ameliorates oxidative stress-induced injury in human and mouse neuronal cells
    American Physiological Society ; 2016
    In:  American Journal of Physiology-Cell Physiology Vol. 310, No. 1 ( 2016-01-01), p. C1-C16
    Details
    In: American Journal of Physiology-Cell Physiology, American Physiological Society, Vol. 310, No. 1 ( 2016-01-01), p. C1-C16
    Abstract: Oxidative stress or reduced expression of naturally occurring antioxidants during aging has been identified as a major culprit in neuronal cell/tissue degeneration. Peroxiredoxin (Prdx) 6, a protective protein with GSH peroxidase and acidic calcium-independent phospholipase A2 activities, acts as a rheostat in regulating cellular physiology by clearing reactive oxygen species (ROS) and thereby optimizing gene regulation. We found that under stress, the neuronal cells displayed reduced expression of Prdx6 protein and mRNA with increased levels of ROS, and the cells subsequently underwent apoptosis. Using Prdx6 fused to TAT transduction domain, we showed evidence that Prdx6 was internalized in human brain cortical neuronal cells, HCN-2, and mouse hippocampal cells, HT22. The cells transduced with Prdx6 conferred resistance against the oxidative stress inducers paraquat, H 2 O 2 , and glutamate. Furthermore, Prdx6 delivery ameliorated damage to neuronal cells by optimizing ROS levels and overstimulation of NF-κB. Intriguingly, transduction of Prdx6 increased the expression of endogenous Prdx6, suggesting that protection against oxidative stress was mediated by both extrinsic and intrinsic Prdx6. The results demonstrate that Prdx6 expression is critical to protecting oxidative stress-evoked neuronal cell death. We propose that local or systemic application of Prdx6 can be an effective means of delaying/postponing neuronal degeneration.
    Type of Medium: Online Resource
    ISSN: 0363-6143 , 1522-1563
    URL: Article
    DOI: 10.1152/ajpcell.00229.2015
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2016
    detail.hit.zdb_id: 1477334-X
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  • 4
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    Online Resource
    Biological roles of angiotensin II via its type 2 receptor during rat follicle atresia
    American Physiological Society ; 1999
    In:  American Journal of Physiology-Endocrinology and Metabolism Vol. 276, No. 1 ( 1999-01-01), p. E25-E33
    Details
    In: American Journal of Physiology-Endocrinology and Metabolism, American Physiological Society, Vol. 276, No. 1 ( 1999-01-01), p. E25-E33
    Abstract: Type 1 angiotensin II (ANG II) receptors play crucial roles in the regulation of blood pressure and fluid osmolarity, whereas the physiological roles of type 2 ANG II receptors (AT 2 ) remain unclear. Because AT 2 is expressed in atretic follicles where granulosa cells undergo apoptosis, we examined the space and time relationship between AT 2 expression and follicle atresia in vivo and the effect of AT 2 on follicle-stimulating hormone (FSH) actions in vitro. Binding studies, autoradiography, and RT-PCR of AT 2 revealed that the AT 2 content in granulosa cells was time dependently increased at both protein and mRNA levels in equine chorionic gonadotropin-treated immature female rats. This increase paralleled the progression of atresia. ANG II suppressed FSH-caused prevention of DNA fragmentation, increases in luteinizing hormone receptor content, and estrogen production through AT 2 in cultured granulosa cells. Moreover, FSH-induced stimulation of extracellular signal-regulated kinase activity, critical for cell survival, was inhibited by AT 2 stimulation. These results suggest that AT 2 mediates the progression of follicle atresia through granulosa cell apoptosis by inhibiting FSH actions.
    Type of Medium: Online Resource
    ISSN: 0193-1849 , 1522-1555
    URL: Article
    DOI: 10.1152/ajpendo.1999.276.1.E25
    Language: English
    Publisher: American Physiological Society
    Publication Date: 1999
    detail.hit.zdb_id: 1477331-4
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  • 5
    Online Resource
    Online Resource
    LEDGF regulation of alcohol and aldehyde dehydrogenases in lens epithelial cells: stimulation of retinoic acid production and protection from ethanol toxicity
    American Physiological Society ; 2004
    In:  American Journal of Physiology-Cell Physiology Vol. 287, No. 2 ( 2004-08), p. C508-C516
    Details
    In: American Journal of Physiology-Cell Physiology, American Physiological Society, Vol. 287, No. 2 ( 2004-08), p. C508-C516
    Abstract: Retinoic acid (RA) is required for the normal growth and maintenance of many cell types, including lens epithelial cells (LECs). Alcohol (ADH) and aldehyde (ALDH) dehydrogenases are implicated in cellular detoxification and conversion of vitamin A to RA. Lens epithelium-derived growth factor (LEDGF) provides cellular protection against stress by transactivating stress-associated genes. Here we show evidence that LEDGF binds and transactivates heat shock (nGAAn) and stress response (A/TGGGGA/T) elements in the promoters of ADH1, ADH4, and retinaldehyde 2 (RALDH2) genes. Electrophoretic mobility and supershift assays disclosed specific binding of LEDGF to nGAAn and A/TGGGGA/T elements in these gene promoters. Transfection experiments in LECs with promoters linked to a chloramphenicol acetyltransferase (CAT) reporter gene along with LEDGF cDNA revealed higher CAT activity. RT-PCR results confirmed that LECs overexpressing LEDGF contained increased levels of ADH1, ADH4, and RALDH2 mRNA. Notably, LECs displayed higher LEDGF mRNA and protein expression during ethanol stress. Cells overexpressing LEDGF typically exhibited elevated RA levels and survived well during ethanol stress. The present findings indicate that LEDGF is one of the transcriptional activators of these genes that facilitates cellular protection against ethanol stress and plays a role in RA production.
    Type of Medium: Online Resource
    ISSN: 0363-6143 , 1522-1563
    URL: Article
    DOI: 10.1152/ajpcell.00076.2004
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2004
    detail.hit.zdb_id: 1477334-X
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  • 6
    Online Resource
    Online Resource
    TAT-mediated PRDX6 protein transduction protects against eye lens epithelial cell death and delays lens opacity
    American Physiological Society ; 2008
    In:  American Journal of Physiology-Cell Physiology Vol. 294, No. 3 ( 2008-03), p. C842-C855
    Details
    In: American Journal of Physiology-Cell Physiology, American Physiological Society, Vol. 294, No. 3 ( 2008-03), p. C842-C855
    Abstract: A diminished level of endogenous antioxidant in cells/tissues is associated with reduced resistance to oxidative stress. Peroxiredoxin 6 (PRDX6), a protective molecule, regulates gene expression/function by controlling reactive oxygen species (ROS) levels. Using PRDX6 protein linked to TAT, the transduction domain from human immunodeficiency virus type 1 TAT protein, we demonstrated that PRDX6 was transduced into lens epithelial cells derived from rat or mouse lenses. The protein was biologically active, negatively regulating apoptosis and delaying progression of cataractogenesis by attenuating deleterious signaling. Lens epithelial cells from cataractous lenses bore elevated levels of ROS and were susceptible to oxidative stress. These cells harbored increased levels of active transforming growth factor (TGF)-β1 and of α-smooth muscle actin and βig-h3, markers for cataractogenesis. Importantly, cataractous lenses showed a 10-fold reduction in PRDX6 expression, whereas TGF-β1 mRNA and protein levels were elevated. The changes were reversed, and cataractogenesis was delayed when PRDX6 was supplied. Results suggest that delivery of PRDX6 can postpone cataractogenesis, and this should be an effective approach to delaying cataracts and other degenerative diseases that are associated with increased ROS.
    Type of Medium: Online Resource
    ISSN: 0363-6143 , 1522-1563
    URL: Article
    DOI: 10.1152/ajpcell.00540.2007
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2008
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  • 7
    Online Resource
    Online Resource
    Deficiency of Prdx6 in lens epithelial cells induces ER stress response-mediated impaired homeostasis and apoptosis
    American Physiological Society ; 2011
    In:  American Journal of Physiology-Cell Physiology Vol. 301, No. 4 ( 2011-10), p. C954-C967
    Details
    In: American Journal of Physiology-Cell Physiology, American Physiological Society, Vol. 301, No. 4 ( 2011-10), p. C954-C967
    Abstract: The multifunctional cytoprotective protein peroxiredoxin 6 (Prdx6) maintains cellular homeostasis and membrane integrity by regulating expression of intracellular reactive oxygen species (ROS) and phospholipid turnover. Using cells derived from targeted inactivation of Prdx6 gene or its depletion by RNA interference or aging, we showed that Prdx6 deficiency in cells evoked unfolded protein response (UPR), evidenced by increased expression or activation of proapoptotic factors, CHOP, ATF4, PERK, IRE-α and eIF2-α and by increased caspases 3 and 12 processing. Those cells displayed enhanced and sustained expression of endoplasmic reticulum (ER) stress-related chaperon proteins, Bip/glucose-regulated protein 78, calnexin, and calreticulin. Under cellular stress induced by hypoxia (1% O 2 or CoCl 2 treatment) or tunicamycin, Prdx6-deficient cells exhibited aberrant activation of ER stress-responsive genes/protein with higher expression of ROS, and died with apoptosis. Wild-type cells exposed to tunicamycin or hypoxia remained relatively insensitive with lower expression of ROS and ER-responsive genes than did Prdx6-deficient cells, but upregulation of ER stress responsive proteins or chaperones mimicked the UPR response of Prdx6-deficient or aging cells. Expression of Prdx6 blocked ER stress-induced deleterious signaling by optimizing physiologically aberrant expression of ER stress responsive genes/proteins in Prdx6-deficient cells or cells facing stressors, and rescued the cells from apoptosis. These findings demonstrate that impaired homeostasis and progression of pathogenesis in Prdx6-deficient lens epithelial cells or in aging cells should be blocked by a supply of Prdx6. The results provide a new molecular basis for understanding the etiology of several age-associated degenerative disorders, and potentially for developing antioxidant Prdx6-based therapeutics.
    Type of Medium: Online Resource
    ISSN: 0363-6143 , 1522-1563
    URL: Article
    DOI: 10.1152/ajpcell.00061.2011
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2011
    detail.hit.zdb_id: 1477334-X
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  • 8
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    Online Resource
    Rebamipide suppresses mite-induced asthmatic responses in NC/Nga mice
    American Physiological Society ; 2015
    In:  American Journal of Physiology-Lung Cellular and Molecular Physiology Vol. 309, No. 8 ( 2015-10-15), p. L872-L878
    Details
    In: American Journal of Physiology-Lung Cellular and Molecular Physiology, American Physiological Society, Vol. 309, No. 8 ( 2015-10-15), p. L872-L878
    Abstract: Allergic asthma caused by continuous allergen exposure evokes allergen-specific Th2 responses and is characterized by chronic airway inflammation and hyperresponsiveness. A previous report showed that rebamipide improved asthmatic symptoms in an ovalbumin/trypsin mice model. However, it is still unclear how rebamipide exerts its effects in asthma. In this study, rebamipide improved the asthmatic responses induced by mite exposure in NC/Nga mice, revealing the mechanism of this therapeutic effect. Rebamipide suppressed the infiltration of eosinophils into the airways and lung as well as attenuating the production of reactive oxygen species in tissues. In addition to these anti-inflammatory effects, rebamipide inhibited the production of IL-33, a member of the IL-1 family that drives the subsequent production of Th2-associated cytokines. These observations identify the point where rebamipide exerts its suppressive action on asthma and suggest that rebamipide has therapeutic potential in preventing mite-induced asthma.
    Type of Medium: Online Resource
    ISSN: 1040-0605 , 1522-1504
    URL: Article
    DOI: 10.1152/ajplung.00194.2015
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2015
    detail.hit.zdb_id: 1477300-4
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  • 9
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    Online Resource
    Regulation of heavy subunit chain of γ-glutamylcysteine synthetase by tumor necrosis factor-α in lens epithelial cells: role of LEDGF/p75
    American Physiological Society ; 2006
    In:  American Journal of Physiology-Cell Physiology Vol. 290, No. 2 ( 2006-02), p. C554-C566
    Details
    In: American Journal of Physiology-Cell Physiology, American Physiological Society, Vol. 290, No. 2 ( 2006-02), p. C554-C566
    Abstract: TNF-α induces oxidative stress by generating reactive oxygen species (ROS). This molecule elevates the expression of γ-glutamylcysteine synthetase heavy subunit (γ-GCS-HS). Lens epithelium-derived growth factor (LEDGF)/p75, a transcriptional protein, is inducible by oxidative stress and protects cells from various stresses by upregulating stress-responsive genes. This paper presents evidence that TNF-α elevates the expression of LEDGF and that LEDGF is one of the transactivators of γ-GCS-HS gene. An analysis of the γ-GCS-HS promoter sequence (−819 to +518 nt) revealed the presence of putative sites for LEDGF binding. Gel mobility assay confirmed the binding of LEDGF to the heat shock element (nGAAn) and the stress response element (A/TGGGGA/T) present in γ-GCS-HS promoter. Transactivation experiments showed activation of γ-GCS-HS promoter in cells overexpressing LEDGF or treated with a sublethal dose of TNF-α (20 ng/ml). Downregulation of γ-GCS-HS promoter activity in cells transfected with LEDGF small interfering RNA validated the finding. Notably, cells treated with TNF-α (20 ng/ml) for 24 h had an increased abundance of LEDGF and γ-GCS-HS mRNA and protein. In contrast, cells treated with TNF-α for longer periods or with higher concentrations of TNF-α showed reduced expression of LEDGF and γ-GCS-HS and increased cellular death with higher ROS levels. Cells overexpressing LEDGF revealed elevated GSH levels (10–15%), a condition that may potentially eliminate the insult to cells induced by TNF-α. Thus TNF-α regulation of LEDGF may be physiologically important, as elevated expression of LEDGF increases the expression of endogenous γ-GCS-HS gene, the catalytic subunit of the regulating enzyme in GSH biosynthesis that may constitute a protective mechanism in limiting oxidative stress induced by inflammatory cytokines.
    Type of Medium: Online Resource
    ISSN: 0363-6143 , 1522-1563
    URL: Article
    DOI: 10.1152/ajpcell.00398.2005
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2006
    detail.hit.zdb_id: 1477334-X
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