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Publication
Journal: Dalton Transactions
August/28/2020
Abstract
Although Ni phosphides are efficient for hydrogen evolution reactions, they are unfavorable for oxygen evolution reactions, so their application in alkaline water electrolysis is limited. It is a feasible method for creating a novel Ni phosphide/oxide heterogeneous interface to promote the oxygen evolution kinetics of Ni phosphide materials in an alkaline medium, yet it has been an unprecedented challenge for researchers. In this work, NiP3@CeO2 hybrid nanoparticles are firstly in situ grown on Ni foam (NiP3@CeO2/NF) via a novel controlled phosphating strategy. The NiP3@CeO2/NF catalysts display a fairly small overpotential of 200 mV to achieve a current density of 25 mA cm-2 for the oxygen evolution reaction (OER) under alkaline conditions, 110 mV smaller than that of NiO@CeO2/NF. It is noteworthy that the improved electrocatalytic performance of NiP3@CeO2/NF can be attributed to rapid electron transfer and the synergistic catalytic effect of the hybrid material. Density functional theory results demonstrate that NiP3 shows a stronger water adsorption energy than CeO2. The novel strategy of controlled phosphating to construct transition metal phosphide/oxide interfaces provides new ideas and methods for the development of efficient and practical water splitting catalysts.
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Publication
Journal: Life Sciences in Space Research
July/28/2020
Abstract
This paper introduces the use of microarray data technology with Medicago (Medicago truncatula) microarrays to characterize global changes in the transcript abundance of etiolated Alaska pea (Pisum sativum L.) seedlings grown under microgravity (µg) conditions in comparison with those under artificial 1 g conditions on the International Space Station. Of the 44,000 genes of the Medicago microarray platform, more than 25,000 transcripts of pea seedlings were hybridized, suggesting that the microarray platform for Medicago could be useful in the study of gene expression of etiolated pea seedlings grown under µg conditions in space. Gene array data were analyzed according to stringent criteria that restricted the scored genes for specific hybridization values at least twofold. Expression of 1362 and 1558 genes in proximal side (the proximal side) and distal side of the epicotyl to the cotyledons (the distal side), respectively, were highly affected by µg conditions in space. Of the genes analyzed, 407 of 1362 transcripts in the proximal side and 740 of 1558 transcripts in the distal side were expressed at ratios at least twofold. However, in the presence of the auxin transport inhibitor TIBA, 212 of 399 transcripts and 255 of 477 transcripts were expressed at ratios at least twofold as high in the proximal and the distal sides of epicotyls in the seedlings grown under µg conditions, respectively. Based on Venn diagram analysis, 31 transcripts and 24 transcripts were found to commonly increase and decrease, respectively, under µg conditions in space. Venn analysis revealed six auxin-related genes and three water channel AQUAPORIN genes that were responsive to gravity. Among 6 auxin-related genes, the accumulation of transcripts of Auxin-induced protein 5NG4 and Indole-3-acetic acid-amido synthetase GH3.3 tended to increase, and that of Auxin-induced protein, Auxin response factor, SAUR-like auxin-responsive family protein and Auxin response factor tended to decrease under µg conditions, whereas there were no statistic differences between under µg and artificial 1 g conditions. Similarly there were no statistic differences between under µg conditions and artificial 1 g, but the accumulation of NIP3-1 and Plasma membrane intrinsic protein11, and AQUAPORIN1/Tonoplast intrinsic protein tended to increase and decrease, respectively. A possible role of auxin-related genes and AQUAPORIN genes in regulating growth of etiolated pea seedlings grown under µg conditions in space is discussed.
Keywords: Aquaporin; International Space Station experiment; Medicago truncatula; Microarray; Pisum sativum; Water channel.
Publication
Journal: The Journal of frailty & aging
November/2/2017
Abstract
Chronic inflammation is associated with muscle weakness and frailty in older adults. The antagonistic cross-talk between macrophage migration inhibitory factor (Mif), an anti-apoptotic cytokine and NIP3-like protein X (Nix), a pro-apoptotic mitochondrial protein, may play a role in mitochondrial free radical homeostasis and inflammatory myopathies. We examined Nix-Mif interaction in inflammation and aging using young and old, IL-10tm/tm (a rodent model of chronic inflammation) and C57BL/6 mice. In this study, we observed that Nix and Mif were co-localized in skeletal muscles of aged and inflamed mice. We show an inflammation- and age-related association between Nix and Mif gene expression, with the strongest positive correlation observed in old IL-10tm/tm skeletal muscles. The IL-10tm/tm skeletal muscles also had the highest levels of oxidative stress damage. These observations suggest that Nix-Mif cross-talk may play a role in the interface between chronic inflammation and oxidative stress in aging skeletal muscles.
Publication
Journal: Journal of Colloid and Interface Science
May/17/2015
Abstract
Three novel Ni(II)-Ion-Imprinted Polymer (IIP) were synthesized by precipitation polymerization of ethylene glycol dimethacrylate (crosslinker) with a complex of nickel(II) and vinylbenzyl iminodiacetic acid (VbIDA). The three IIPs were prepared with various mixtures of porogen solvents: methanol, methanol/2-methoxyethanol and methanol/acetonitrile (IIP1, IIP2 and IIP3, respectively). Non-Imprinted Polymers (NIP1, NIP2 and NIP3) were prepared as control polymers in similar conditions but with pure VbIDA instead of VbIDA-Ni. These polymers were characterized by FTIR, BET, SEM and tested for their efficiency and selectivity in Ni(II) retention. The most efficient (IIP1, around 12 mg g(-1) of nickel) was then positively checked for Ni(II) retention in presence of some competing species over a wide range of concentration. Finally Ni(II) retention by IIP1 was successfully demonstrated in natural samples. The modelling of the different experiments (Langmuir, Freundlich but also PROSECE and WHAM VII, frequently used in environmental studies) allowed demonstrating the presence of completely different binding sites when considering the ion-imprinted polymer and the non-imprinted one, and therefore led to a better understanding of what the imprinting effect is.
Publication
Journal: Cellular and Molecular Immunology
November/29/2021
Abstract
The global coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused severe morbidity and mortality in humans. It is urgent to understand the function of viral genes. However, the function of open reading frame 10 (ORF10), which is uniquely expressed by SARS-CoV-2, remains unclear. In this study, we showed that overexpression of ORF10 markedly suppressed the expression of type I interferon (IFN-I) genes and IFN-stimulated genes. Then, mitochondrial antiviral signaling protein (MAVS) was identified as the target via which ORF10 suppresses the IFN-I signaling pathway, and MAVS was found to be degraded through the ORF10-induced autophagy pathway. Furthermore, overexpression of ORF10 promoted the accumulation of LC3 in mitochondria and induced mitophagy. Mechanistically, ORF10 was translocated to mitochondria by interacting with the mitophagy receptor Nip3-like protein X (NIX) and induced mitophagy through its interaction with both NIX and LC3B. Moreover, knockdown of NIX expression blocked mitophagy activation, MAVS degradation, and IFN-I signaling pathway inhibition by ORF10. Consistent with our observations, in the context of SARS-CoV-2 infection, ORF10 inhibited MAVS expression and facilitated viral replication. In brief, our results reveal a novel mechanism by which SARS-CoV-2 inhibits the innate immune response; that is, ORF10 induces mitophagy-mediated MAVS degradation by binding to NIX.
Keywords: MAVS; NIX; ORF10; SARS-CoV-2; mitophagy.
Publication
Journal: Ecotoxicology and Environmental Safety
January/2/2022
Abstract
Cadmium (Cd) has well-known central nervous system toxicity, and mitochondria are direct targets of Cd-induced neuronal toxicity. However, how Cd induces mitochondrial mass decrease in terms of its neurotoxic effects remains unknown. Puerarin, an isoflavone extracted from kudzu root, can cross the blood-brain barrier and exert protective effects in nervous system disease. The purpose of the study was to determine the mechanism of Cd-induced mitochondrial mass decrease and the protective role of puerarin in rat cortical neurons. The results indicated that Cd induced mitochondrial mass decrease by activating mitophagy mediated by the PTEN-induced putative kinase protein 1 (PINK1)-E3 ubiquitin ligase (Parkin) and Nip3-like protein X (Nix) pathways in rat cortical neurons. Puerarin improved the Cd-induced decrease in mitochondrial membrane potential (MMP) in vitro, and blocked PINK1-Parkin and Nix-mediated mitophagy, inhibiting Cd-induced mitochondrial mass decrease in rat cortical neurons in vitro and in vivo. In summary, our data clearly indicated that puerarin protects rat cortical neurons against Cd-induced neurotoxicity by ameliorating mitochondrial damage, inhibiting mitophagy-mediated mitochondrial mass decrease. Puerarin appears to have great potential as a neuroprotective agent.
Keywords: Cadmium; Mitochondrial mass; Mitophagy; Neuron; Puerarin.
Results with error correction
Publication
Journal: Nature Reviews Molecular Cell Biology
January/20/2011
Abstract
Autophagy not only recycles intracellular components to compensate for nutrient deprivation but also selectively eliminates organelles to regulate their number and maintain quality control. Mitophagy, the specific autophagic elimination of mitochondria, has been identified in yeast, mediated by autophagy-related 32 (Atg32), and in mammals during red blood cell differentiation, mediated by NIP3-like protein X (NIX; also known as BNIP3L). Moreover, mitophagy is regulated in many metazoan cell types by parkin and PTEN-induced putative kinase protein 1 (PINK1), and mutations in the genes encoding these proteins have been linked to forms of Parkinson's disease.
Publication
Journal: Proceedings of the National Academy of Sciences of the United States of America
September/4/2000
Abstract
The ability to sense and respond to changes in oxygen availability is critical for many developmental, physiological, and pathological processes, including angiogenesis, control of blood pressure, and cerebral and myocardial ischemia. Hypoxia-inducible factor-1alpha (HIF-1alpha) is a basic-helix-loop-helix (bHLH)containing member of the PER-ARNT-SIM (PAS) family of transcription factors that plays a central role in the response to hypoxia. HIF-1alpha, and its relatives HIF-2alpha/endothelial PAS domain protein (EPAS) and HIF-3alpha, are induced in response to hypoxia and serve to coordinately activate the expression of target genes whose products facilitate cell survival under conditions of oxygen deprivation. When cells are exposed to chronic hypoxia, the protective response can fail, resulting in apoptosis. This study shows that transcription of the gene encoding Nip3, a proapoptotic member of the Bcl-2 family of cell death factors, is strongly induced in response to hypoxia. The Nip3 promoter contains a functional HIF-1-responsive element (HRE) and is potently activated by both hypoxia and forced expression of HIF-1alpha. Exposure of cultured cells to chronic hypoxia results in the accumulation of a protein recognized by antibodies raised against Nip3. This study demonstrates a direct link between HIF-1alpha and a proapoptotic member of the Bcl-2 family and offers a reasonable physiological function for members of the Bcl-2 subfamily, including Nip3 and its close relative Nix. These observations indicate that Nip3 may play a dedicated role in the pathological progression of hypoxia-mediated apoptosis, as observed after ischemic injury.
Authors
Publication
Journal: Cancer Research
October/10/2001
Abstract
Solid tumors contain regions of hypoxia, a physiological stress that can activate cell death pathways and, thus, result in the selection of cells resistant to death signals and anticancer therapy. Bcl2/adenovirus EIB 19kD-interacting protein 3 (BNIP3) is a cell death factor that is a member of the Bcl-2 proapoptotic family recently shown to induce necrosis rather than apoptosis. Using cDNA arrays and serial analysis of gene expression, we found that hypoxia induces up-regulation of BNIP3 and its homologue, Nip3-like protein X. Analysis of human carcinoma cell lines showed that they are hypoxically regulated in many tumor types, as well as in endothelial cells and macrophages. Regulation was hypoxia inducible factor-1-dependent, and hypoxia inducible factor-1 expression was suppressed by von Hippel-Lindau protein in normoxic cells. Northern blotting and in situ hybridization analysis has revealed that these factors are highly expressed in human tumors compared with normal tissue and that BNIP3 is up-regulated in perinecrotic regions of the tumor. This study shows that genes regulating cell death can be hypoxically induced and are overexpressed in clinical tumors.
Publication
Journal: Molecular and Cellular Biology
August/9/2000
Abstract
Many apoptotic signaling pathways are directed to mitochondria, where they initiate the release of apoptogenic proteins and open the proposed mitochondrial permeability transition (PT) pore that ultimately results in the activation of the caspase proteases responsible for cell disassembly. BNIP3 (formerly NIP3) is a member of the Bcl-2 family that is expressed in mitochondria and induces apoptosis without a functional BH3 domain. We report that endogenous BNIP3 is loosely associated with mitochondrial membrane in normal tissue but fully integrates into the mitochondrial outer membrane with the N terminus in the cytoplasm and the C terminus in the membrane during induction of cell death. Surprisingly, BNIP3-mediated cell death is independent of Apaf-1, caspase activation, cytochrome c release, and nuclear translocation of apoptosis-inducing factor. However, cells transfected with BNIP3 exhibit early plasma membrane permeability, mitochondrial damage, extensive cytoplasmic vacuolation, and mitochondrial autophagy, yielding a morphotype that is typical of necrosis. These changes were accompanied by rapid and profound mitochondrial dysfunction characterized by opening of the mitochondrial PT pore, proton electrochemical gradient (Deltapsim) suppression, and increased reactive oxygen species production. The PT pore inhibitors cyclosporin A and bongkrekic acid blocked mitochondrial dysregulation and cell death. We propose that BNIP3 is a gene that mediates a necrosis-like cell death through PT pore opening and mitochondrial dysfunction.
Publication
Journal: Cell
November/28/1994
Abstract
Adenovirus E1B 19 kDa protein protects against cell death induced by viral infection and certain external stimuli. The Bcl-2 protein can functionally substitute for the E1B 19 kDa protein. To identify cellular targets for the 19 kDa protein, we used the two-hybrid screen in yeast. We have isolated cDNAs for three different proteins, designated Nip1, Nip2, and Nip3, that interact with the 19 kDa protein. Mutational analysis indicates that these proteins do not associate with 19 kDa mutants defective in suppression of cell death, suggesting a correlation between interaction of these proteins and suppression of cell death. These proteins also associate with discrete sequence motifs in the Bcl-2 protein that are homologous to motifs of the 19 kDa protein. Our results suggest that two diverse proteins, the E1B 19 kDa and the Bcl-2 proteins, promote cell survival through interaction with a common set of cellular proteins.
Publication
Journal: Journal of Biological Chemistry
February/17/2000
Abstract
BNIP3 (formerly NIP3) is a pro-apoptotic, mitochondrial protein classified in the Bcl-2 family based on limited sequence homology to the Bcl-2 homology 3 (BH3) domain and COOH-terminal transmembrane (TM) domain. BNIP3 expressed in yeast and mammalian cells interacts with survival promoting proteins Bcl-2, Bcl-X(L), and CED-9. Typically, the BH3 domain of pro-apoptotic Bcl-2 homologues mediates Bcl-2/Bcl-X(L) heterodimerization and confers pro-apoptotic activity. Deletion mapping of BNIP3 excluded its BH3-like domain and identified the NH(2) terminus (residues 1-49) and TM domain as critical for Bcl-2 heterodimerization, and either region was sufficient for Bcl-X(L) interaction. Additionally, the removal of the BH3-like domain in BNIP3 did not diminish its killing activity. The TM domain of BNIP3 is critical for homodimerization, pro-apoptotic function, and mitochondrial targeting. Several TM domain mutants were found to disrupt SDS-resistant BNIP3 homodimerization but did not interfere with its killing activity or mitochondrial localization. Substitution of the BNIP3 TM domain with that of cytochrome b(5) directed protein expression to nonmitochondrial sites and still promoted apoptosis and heterodimerization with Bcl-2 and Bcl-X(L). We propose that BNIP3 represents a subfamily of Bcl-2-related proteins that functions without a typical BH3 domain to regulate apoptosis from both mitochondrial and nonmitochondrial sites by selective Bcl-2/Bcl-X(L) interactions.
Publication
Journal: Journal of Experimental Medicine
January/12/1998
Abstract
Nip3 (nineteen kD interacting protein-3) is an E1B 19K and Bcl-2 binding protein of unknown function. Nip3 is detected as both a 60- and 30-kD protein in vivo and in vitro and exhibits strong homologous interaction in a yeast two-hybrid system indicating that it can homodimerize. Nip3 is expressed in mitochondria and a mutant (Nip3(163)) lacking the putative transmembrane domain and COOH terminus does not dimerize or localize to mitochondria. Transient transfection of epitope-tagged Nip3 in Rat-1 fibroblasts and MCF-7 breast carcinoma induces apoptosis within 12 h while cells transfected with the Nip3(163) mutant have a normal phenotype, suggesting that mitochondrial localization is necessary for induction of cell death. Nip3 overexpression increases the sensitivity to apoptosis induced by granzyme B and topoisomerase I and II inhibitors. After transfection, both Nip3 and Nip3(163) protein levels decrease steadily over 48 h indicating that the protein is rapidly degraded and this occurs in the absence of cell death. Bcl-2 overexpression initially delays the onset of apoptosis induced by Nip3 but the resistance is completely overcome in longer periods of incubation. Nip3 protein levels are much higher and persist longer in Bcl-2 expressing cells. In conclusion, Nip3 is an apoptosis-inducing dimeric mitochondrial protein that can overcome Bcl-2 suppression.
Publication
Journal: Journal of Biological Chemistry
February/4/1999
Abstract
We have identified Nix, a homolog of the E1B 19K/Bcl-2 binding and pro-apoptotic protein Nip3. Human and murine Nix have a 56 and 53% amino acid identity to human and murine Nip3, respectively. The carboxyl terminus of Nix, including a transmembrane domain, is highly homologous to Nip3 but it bears a longer and distinct asparagine/proline-rich N terminus. Human Nip3 maps to chromosome 14q11.2-q12, whereas Nix/BNip3L was found on 8q21. Nix encodes a 23. 8-kDa protein but it is expressed as a 48-kDa protein, suggesting that it homodimerizes similarly to Nip3. Following transfection, Nix protein undergoes progressive proteolysis to an 11-kDa C-terminal fragment, which is blocked by the proteasome inhibitor lactacystin. Nix colocalizes with the mitochondrial matrix protein HSP60, and removal of the putative transmembrane domain (TM) results in general cytoplasmic and nuclear expression. When transiently expressed, Nix and Nip3 but not TM deletion mutants rapidly activate apoptosis. Nix can overcome the suppressers Bcl-2 and Bcl-XL, although high levels of Bcl-XL expression will inhibit apoptosis. We propose that Nix and Nip3 form a new subfamily of pro-apoptotic mitochondrial proteins.
Publication
Journal: Journal of Virology
January/10/2002
Abstract
The Kaposi's sarcoma-associated herpesvirus (KSHV) (or human herpesvirus 8) open reading frame (ORF) K15 encodes a putative integral transmembrane protein in the same genomic location as latent membrane protein 2A of Epstein-Barr virus. Ectopic expression of K15 in cell lines revealed the presence of several different forms ranging in size from full length, approximately 50 kDa, to 17 kDa. Of these different species the 35- and 23-kDa forms were predominant. Mutational analysis of the initiator AUG indicated that translation initiation from this first AUG is required for K15 expression. Computational analysis indicates that the different forms detected may arise due to proteolytic cleavage at internal signal peptide sites. We show that K15 is latently expressed in KSHV-positive primary effusion lymphoma cell lines and in multicentric Castleman's disease. Using a yeast two-hybrid screen we identified HAX-1 (HS1 associated protein X-1) as a binding partner to the C terminus of K15 and show that K15 interacts with cellular HAX-1 in vitro and in vivo. Furthermore, HAX-1 colocalizes with K15 in the endoplasmic reticulum and mitochondria. The function of HAX-1 is unknown, although the similarity of its sequence to those of Nip3 and Bcl-2 infers a role in the regulation of apoptosis. We show here that HAX-1 can form homodimers in vivo and is a potent inhibitor of apoptosis and therefore represents a new apoptosis regulatory protein. The putative functions of K15 with respect to its interaction with HAX-1 are discussed.
Publication
Journal: Journal of Biological Chemistry
June/11/1998
Abstract
Adenovirus E1B-19K and BCL-2 anti-apoptosis proteins interact with certain BCL-2 family pro-apoptotic proteins. A conserved domain, BH3, present in these proteins is essential for their pro-apoptotic activity and for heterodimerization with anti-apoptosis proteins. Cellular protein BNIP3 (previously NIP3) interacts with E1B-19K, BCL-2, BCL-xL, and EBV-BHRF1. BNIP3 contains a motif similar to the BH3 domain. Deletion of the BH3-like motif in BNIP3 abrogates its ability to heterodimerize with E1B-19K and BCL-xL. Substitution of the BH3 domain of BNIP3 for the corresponding sequences of BAX functionally restores the pro-apoptotic and protein heterodimerization activities of BAX. BNIP3 exhibits a delayed cell death activity that is partially relieved by deletion of the BH3 domain. BNIP3 suppresses the anti-apoptosis activity of BCL-xL in a BH3-dependent manner. BNIP3 contains a C-terminal trans-membrane (TM) domain similar to other BCL-2 family proteins and BNIP1 (previously NIP1). The TM domains of BNIP3 and BNIP1 can functionally substitute for the TM domain of a BCL-2 family member EBV-BHRF1. The BNIP3 TM domain exclusively targets the heterologous green fluorescent protein (GFP) to mitochondria. These results suggest that BNIP3 is a member of the BH3-contaning BCL-2 family of pro-apoptotic proteins and functions in mitochondria.
Publication
Journal: Neuroscience
January/25/2007
Abstract
The transcription factor Sox11 is expressed at high levels in developing sensory neurons and injured adult neurons but little is known about its transcriptional targets and function. In this study we examined the role of Sox11 using Neuro2a neuroblastoma cells and cultured mouse dorsal root ganglia (DRG) neurons. Results show Sox11 has an essential role in regulation of neuron survival and neurite outgrowth in Neuro2a cells and primary sensory neurons. Neuro2a cells increase expression of Sox11 as they differentiate in culture. Following addition of 20 microM retinoic acid (RA), a stimulus for differentiation that enhances neurite growth and differentiation, Sox11 level rises. RNAi-mediated knockdown of Sox11 in RA-differentiated Neuro2a cells caused a decrease in neurite growth and an increase in the percent of apoptotic cells. RNA expression analysis showed that Sox11 knockdown modulated the level of mRNAs encoding several genes related to cell survival and death. Further validation in the Neuro2a model showed Sox11 knockdown increased expression of the pro-apoptotic gene BNIP3 (BclII interacting protein 1 NIP3) and decreased expression of the anti-apoptotic gene TANK (TNF receptor-associated factor family member-associated NFkappaB activator). Cultured primary DRG neurons also express Sox11 and treatment with Sox11 small interfering RNA (siRNA) caused a significant decrease in neurite growth and branching and a decrease in mRNA encoding actin-related protein complex 3 (Arpc3), an actin organizing protein that may be involved in axon growth. The percent of apoptotic neurons also increased in cultures of DRG neurons treated with Sox11 siRNA. Similar to Neuro2a cells, a decrease in TANK gene expression occurred, suggesting at least some overlap in Sox11 transcriptional targets in Neuro2a and DRG neurons. These data are consistent with a central role for Sox11 in regulating events that promote neurite growth and neuron survival.
Publication
Journal: Brain Research
May/27/2004
Abstract
The 19 kD interacting protein 3, Nip3/BNIP3, is a pro-apoptotic member of the Bcl-2 family induced during hypoxia via the hypoxia-inducible factor (HIF) 1. BNIP3 has been linked to both apoptotic and necrotic cell death involving mitochondrial permeability transition. Since apoptotic and necrotic mechanisms may occur in brain ischemia, immunohistochemical changes of BNIP3 were studied at 1, 2, 3 and 7 days after transient global brain ischemia (12.5 min) in ventilated normothermic rats. In control brains, BNIP3-like immunoreactivity was moderately strong in neuronal processes or cytoplasm and absent in the nucleus. In the ischemia-vulnerable CA1 neurons, BNIP3-positive granules were seen in the nucleus at 1 and 2 days, and these neurons were damaged at 3 and 7 days. The resistant CA3 neurons showed nuclear BNIP3 labeling by 1 day and then returned to the normal state. BNIP3-positive granules did not overlap with the nucleolus. Constitutively expressed BNIP3 may participate in apoptotic and necrotic processes after brain ischemia. Nuclear location of BNIP3 after brain ischemia indicates a novel role for the regulation of cell survival in neurons or a general disturbance of the nuclear envelope.
Publication
Journal: Journal of Experimental Medicine
July/17/1975
Abstract
Normal mouse spleen cells were fractionated in dishes coated with thin layers of DNP-gelatin or NIP-gelatin, which were insoluble at 4 degrees C. Highly viable cells were recovered from the dishes by melting the gel at 37 degrees C. NIP3- gelatin layers bound approximately 0.1% and DNP4-gelatin layers 0.5% of normal spleen cells. Increasing numbers of low affinity cells were bound with increasing DNP density of the adsorbent. The binding to insoluble DNP-gelatin was hapten-specific since it was inhibited by DNP-lysine, soluble DNP-gelatin or DNP-BSA but not by soluble gelatin or bovine serum albumin (BSA). It was also inhibited by a polyvalent rabbit antimouse Ig. DNP-gelatin was detected on the surface of cells recovered from DNP-gelatin-coated dishes by 125-I-labeled anti-DNP Ig. The cell surface bound DNP-gelatin could be removed by treatment with collagenase. Collagenase treatment did not detectably affect cell viability or surface receptors. More than 90% of DNP-gelatin binding cells were labeled with a polyvalent 125-I-labeled antimouse Ig before or after collagenase treatment under conditions known to label B lymphocytes. Furthermore, the specific antigen-binding capacity of the purified cell populations could be demonstrated after treatment with collagenase. Purified DNP4-gelatin binding cells contained more than 100 times as many DNP-RFC than unfractionated cells. The enrichment of NIP-RFC in the cell population recovered from NIP3 gelatin-coated dishes was more than 200-fold.
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Publication
Journal: Scientific Reports
October/7/2017
Abstract
Therapeutic targets are needed to develop neuroprotective treatments for Parkinson's disease (PD). Mitophagy, the selective autophagic elimination of dysfunctional mitochondria, is essential for the maintenance of mitochondrial integrity and is predominantly regulated by the PINK1/Parkin-mediated pathway. Loss of function mutations in Parkin and PINK1 cause an accumulation of dysfunctional mitochondria, leading to nigral neurodegeneration and early-onset PD with a high penetrance rate. We previously identified an asymptomatic homozygous Parkin mutation carrier who had not developed PD by her eighth decade despite the loss of functional Parkin. Here we discover a putative mechanism that protects her against PD. In contrast to Parkin-related PD patient-derived cells, the asymptomatic carrier cells show preserved mitochondrial function and mitophagy which is mediated by mitochondrial receptor Nip3-like protein X (Nix). Nix-mediated mitophagy was not affected by PINK1 knockdown. Both genetic and pharmacological induction of Nix restores mitophagy in PINK1- and Parkin-related PD patient cell lines, confirming its ability to induce mitophagy in the absence of PINK1/Parkin-mediated pathway. Moreover, Nix over-expression improves mitochondrial ATP production in these patient cells. Our results demonstrate that Nix can serve as an alternative mediator of mitophagy to maintain mitochondrial turnover, identifying Nix as a promising target for neuroprotective treatment in PINK1/Parkin-related PD.
Publication
Journal: Cancer Research
August/24/2003
Abstract
Nickel is a potent environmental pollutant in industrial countries. Because nickel compounds are carcinogenic, exposure to nickel represents a serious hazard to human health. The understanding of how nickel exerts its toxic and carcinogenic effects at a molecular level may be important in risk assessment, as well as in the treatment and prevention of occupational diseases. Previously, using human and rodent cells in vitro, we showed that hypoxia-inducible signaling pathway was activated by carcinogenic nickel compounds. Acute exposure to nickel resulted in the accumulation of hypoxia-inducible transcription factor (HIF)-1, which strongly activated hypoxia-inducible genes, including the recently discovered tumor marker NDRG1 (Cap43). To further identify HIF-1-dependent nickel-inducible genes and to understand the role of the HIF-dependent signaling pathway in nickel-induced transformation, we used the Affymetrix GeneChip to compare the gene expression profiles in wild-type cells or in cells from HIF-1 alpha knockout mouse embryos exposed to nickel chloride. As expected, when we examined 12,000 genes for expression changes, we found that genes coding for glycolytic enzymes and glucose transporters, known to be regulated by HIF-1 transcription factor, were induced by nickel only in HIF-1 alpha-proficient cells. In addition, we found a number of other hypoxia-inducible genes up-regulated by nickel in a HIF-dependent manner including BCL-2-binding protein Nip3, EGLN1, hypoxia-inducible gene 1 (HIG1), and prolyl 4-hydroxylase. Additionally, we found a number of genes induced by nickel in a HIF-independent manner, suggesting that Ni activated other signaling pathways besides HIF-1. Finally, we found that in HIF-1 alpha knockout cells, nickel strongly induced the expression of the whole group of genes that were not expressed in the presence of HIF-1. Because the majority of modulated genes were induced or suppressed by nickel in a HIF-1-dependent manner, we elucidated the role of HIF-1 transcription factor in cell transformation. In HIF-1 alpha-proficient cells, nickel exposure increased soft agar growth, whereas it decreased soft agar growth in HIF-1 alpha-deficient cells. We hypothesize that the induction of HIF-1 transcription factor by nickel may be important during the nickel-induced carcinogenic process.
Publication
Journal: Biochemical Pharmacology
March/22/2007
Abstract
Cobalt is suspected to cause memory deficit in humans and was reported to induce neurotoxicity in animal models. We have studied the effects of cobalt in primary cultures of mouse astrocytes. CoCl(2) (0.2-0.8mM) caused dose-dependent ATP depletion, apoptosis (cell shrinkage, phosphatidylserine externalization and chromatin rearrangements) and secondary necrosis. The mitochondria appeared to be a main target of cobalt toxicity, as shown by the loss of mitochondrial membrane potential (DeltaPsi(m)) and release from the mitochondria of apoptogenic factors, e.g. apoptosis inducing factor (AIF). Pre-treatment with bongkrekic acid reduced ATP depletion, implicating the involvement of the mitochondrial permeability transition (MPT) pore. Cobalt increased the generation of oxygen radicals, but antioxidants did not prevent toxicity. There was also an impaired response to ATP stimulation, evaluated as a lower raise in intracellular calcium. Similarly to hypoxia and dymethyloxallyl glycine (DMOG), cobalt triggered stabilization of the alpha-subunit of hypoxia-inducible factor HIF-1 (HIF-1alpha). This early event was followed by an increased expression of HIF-1 regulated genes, e.g. stress protein HO-1, pro-apoptotic factor Nip3 and iNOS. Although all of the three stimuli activated the HIF-1alpha pathway and decreased ATP levels, the downstream effects were different. DMOG only inhibited cell proliferation, whereas the other two conditions caused cell death by apoptosis and necrosis. This points to cobalt and hypoxia not only inducing HIF-1alpha regulated genes but also affecting similarly other cellular functions, including metabolism.
Publication
Journal: Genes Chromosomes and Cancer
May/3/1998
Abstract
We have isolated a novel cDNA that encodes a product showing significant sequence homology (56% identity) to human NIP3, a protein thought to interact with adenovirus E1B19kD and human BCL2 proteins. This cDNA contains an open reading frame of 657 nucleotides encoding a 219 amino acid polypeptide. The gene, designated BNIP3L, was expressed in all 16 normal human tissues examined; we mapped it to chromosome band 8p21 by fluorescence in situ hybridization. Introduction of the BNIP3L gene into six different cancer-cell lines caused significant growth suppression in each of them, while no such effect occurred when the antisense cDNA or the vector DNA was transfected, indicating that BNIP3L may function as a tumor suppressor.
Publication
Journal: BMC Microbiology
April/3/2007
Abstract
BACKGROUND
Porphyromonas gingivalis is the foremost oral pathogen of adult periodontitis in humans. However, the mechanisms of bacterial invasion and the resultant destruction of the gingival tissue remain largely undefined.
RESULTS
We report host-P. gingivalis interactions in primary human gingival fibroblast (HGF) cells. Quantitative immunostaining revealed the need for a high multiplicity of infection for optimal infection. Early in infection (2-12 h), P. gingivalis activated the proinflammatory transcription factor NF-kappa B, partly via the PI3 kinase/AKT pathway. This was accompanied by the induction of cellular anti-apoptotic genes, including Bfl-1, Boo, Bcl-XL, Bcl2, Mcl-1, Bcl-w and Survivin. Late in infection (24-36 h) the anti-apoptotic genes largely shut down and the pro-apoptotic genes, including Nip3, Hrk, Bak, Bik, Bok, Bax, Bad, Bim and Moap-1, were activated. Apoptosis was characterized by nuclear DNA degradation and activation of caspases-3, -6, -7 and -9 via the intrinsic mitochondrial pathway. Use of inhibitors revealed an anti-apoptotic function of NF-kappa B and PI3 kinase in P. gingivalis-infected HGF cells. Use of a triple protease mutant P. gingivalis lacking three major gingipains (rgpA rgpB kgp) suggested a role of some or all these proteases in myriad aspects of bacteria-gingival interaction.
CONCLUSIONS
The pathology of the gingival fibroblast in P. gingivalis infection is affected by a temporal shift from cellular survival response to apoptosis, regulated by a number of anti- and pro-apoptotic molecules. The gingipain group of proteases affects bacteria-host interactions and may directly promote apoptosis by intracellular proteolytic activation of caspase-3.
Publication
Journal: Molecules and Cells
June/12/2003
Abstract
We performed gene expression profiling of normal and hepatocellular carcinoma (HCC) liver tissues using a high-density microarray that contained 3,063 human cDNA. The results of a microarray hybridization experiment from eight different HCC tissues were analyzed and classified by the Cluster program. Among these differentially-expressed genes, the galectin-3, serine/threonine kinase SGK, translation factor eIF-4A, -4B, -3, fibroblast growth factor receptor, and ribosomal protein L35A were up-regulated; the mRNAs of Nip3, decorin, and the insulin-like growth factor binding protein-3 were down-regulated in HCC. The differential expression of these genes was further confirmed by an RT-PCR analysis. In addition, our data suggest that the gene expression profile of HCC varies according to the histological types.
Publication
Journal: Nucleic Acids Research
November/23/1995
Abstract
It has been shown that the monomethylated cap structure plays important roles in pre-mRNA splicing and nuclear export of RNA. As a candidate for the factor involved in these nuclear events we have previously purified an 80 kDa nuclear cap binding protein (NCBP) from a HeLa cell nuclear extract and isolated its full-length cDNA. In this report, in order to obtain a clue to the cellular functions of NCBP, we attempted to identify a factor(s) that interacts with NCBP. Using the yeast two-hybrid system we isolated three clones from a HeLa cell cDNA library. We designated the proteins encoded by these clones NIPs (NCBP interacting proteins). NIP1 and NIP2 have an RNP consensus-type RNA binding domain, whereas NIP3 contains a unique domain of Arg-Glu or Lys-Glu dipeptide repeats. We also show that NCBP requires NIP1 for binding to the cap structure. Possible roles of NIPs in cap-dependent nuclear processes are discussed.
Publication
Journal: Journal of Surgical Research
December/29/1999
Abstract
BACKGROUND
Physiologically programmed cell death or apoptosis occurs during the natural balance between cellular proliferation and demise.
METHODS
We compared the expression of 64 apoptosis-related genes in keloids and normal scars to investigate the potential role of apoptosis in keloid formation. Two sets of mRNA were isolated from keloids excised from four previously untreated patients and four normal scar patients separately. Human cDNA arrayed hybridization was performed to compare the apoptosis-related gene expression between these two groups. In addition, TUNEL assays were performed to evaluate the percentage of apoptotic cells in keloids (center and periphery) versus normal scars.
RESULTS
Eight of the sixty-four apoptosis-related genes studied were significantly underexpressed in keloid tissue. The underexpressed genes and their relative expression compared with normal scar were defender against cell death 1 (DAD-1) (34.1% of normal scar); nucleoside diphosphate kinase B (c-myc transcription factor) (24.7%); glutathione S-transferase (17.9%); glutathione S-transferase microsomal (28.1%); glutathione peroxidase (47.2%); tumor necrosis factor receptor 1-associated protein (TRADD) (51.0%); 19-kDa interacting protein 3 (NIP3) (36.0%); and cytoplasmic dynein light chain 1 (HDLC1) (47.7%). Spatial analysis of apoptosis using TUNEL assays revealed apoptosis indices of 0.83 for keloid periphery and 0.63 for keloid center.
CONCLUSIONS
In this study we demonstrated underexpression of apoptosis-related genes in human keloid tissue and decreased apoptotic activity in fibroblasts derived from keloids versus normal scars. We hypothesized that keloid fibroblasts fail to undergo physiologically programmed cell death and, thus, continue to produce and secrete connective tissue beyond the period expected in normal scar formation, accounting for the progressive and hypertrophic nature of keloids. This mechanism leads to new possibilities for treatment of keloids through induction of apoptosis.
Publication
Journal: Neurotoxicology and Teratology
May/1/2005
Abstract
It has been demonstrated that exposure to cocaine increases cell death in the fetal CNS. To examine the molecular mechanisms of this effect, we employed mouse oligo microarrays followed by real-time reverse transcriptase-polymerase chain reaction (real-time RT-PCR) to compare expressions of apoptosis-related genes in the cerebral wall of 18-day-old (E18) fetuses from cocaine-treated (20 mg/kg cocaine, s.c., b.i.d., E8th-E18th) and drug-naive (saline, s.c.) mice. Out of approximately 400 relevant genes in the arrays, 53 showed alterations in expression in cocaine-exposed fetuses. Upregulation was observed in 35 proapoptotic and 8 antiapoptotic genes; 4 proapoptotic and 6 antiapoptotic genes were down-regulated. The affected genes encode a wide range of apoptosis-related proteins, including death receptors (NTF-R1, NTF-R2, DR3, DR5, LTbeta-R, GITR, P57 TR-1) and their adaptor and regulatory proteins (MASGE-D1, TRAF-2, SIVA, MET, FLIP, FAIM, IAP1, ATFA), members of transcription regulatory pathways (JNK, NF-kappaB, P53), members of BCL-2 family of proteins (BID, BAD, BAX, BIK, NIP21, NIP3, NIX, BCL-2), DNA damage sensor (PARP-1), caspases and their substrates and regulatory proteins (caspases 8, 4, 9, and 3, ACINUS, CIDE-A, CIDE-B, GAS2), mitochondrially released factors (cytochrome c, AIF, PRG3), specific endoplasmic reticulum- and oxidative stress-associated factors (BACH2, ABL1, ALG2, CHOP), members of cell survival AKT and HSP70 pathways (PIK3GA, PTEN, HSP70, BAG1, BAG2), and others. This suggests that cocaine affects survival of developing cerebral cells via multiple apoptosis-regulating mechanisms.
Publication
Journal: Journal of Clinical Investigation
December/6/2010
Abstract
Mutations in pancreatic duodenal homeobox (PDX1) are linked to human type 2 diabetes and maturity-onset diabetes of the young type 4. Consistent with this, Pdx1-haploinsufficient mice develop diabetes. Both apoptosis and necrosis of β cells are mechanistically implicated in diabetes in these mice, but a molecular link between Pdx1 and these 2 forms of cell death has not been defined. In this study, we introduced an shRNA into mouse insulinoma MIN6 cells to deplete Pdx1 and found that expression of proapoptotic genes, including NIP3-like protein X (Nix), was increased. Forced Nix expression in MIN6 and pancreatic islet β cells induced programmed cell death by simultaneously activating apoptotic and mitochondrial permeability transition-dependent necrotic pathways. Preventing Nix upregulation during Pdx1 suppression abrogated apoptotic and necrotic β cell death in vitro. In Pdx1-haploinsufficient mice, Nix ablation normalized pancreatic islet architecture, β cell mass, and insulin secretion and eliminated reactive hyperglycemia after glucose challenge. These results establish Nix as a critical mediator of β cell apoptosis and programmed necrosis in Pdx1-deficient diabetes.
Publication
Journal: Journal of Biological Chemistry
July/1/2002
Abstract
Pleomorphic adenomas gene-like 2 (PLAGL2) protein containing seven C(2)H(2) zinc finger motifs exhibits DNA binding and transcriptional activation activity and is expressed in response to hypoxia or iron deficiency. To identify the target genes of PLAGL2, we transfected mouse PLAGL2 cDNA into Balb/c3T3 fibroblasts and neuroblastoma Neuro2a cells. Both cells were induced to undergo apoptosis by the expression of PLAGL2 as judged by assays of TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling), DNA fragmentation, propidium iodide staining, and the binding of annexin V to the cell surface. The treatment of the cells with an iron chelator, desferrioxamine, resulted in the induction of apoptosis with a concomitant accumulation of PLAGL2 in the nucleus. The expression of PLAGL2 in Balb/c3T3 cells led to the mRNA expression of a proapoptotic factor, Nip3, which can dimerize with Bcl-2. Nip3 mRNA was also induced in desferrioxamine-treated cells. Furthermore, the Nip3 promoter containing a hypoxia-responsive element was activated by PLAGL2, independent of hypoxia-inducible factor-1 (HIF-1). The transfection of antisense oligonucleotide to mouse Nip3 mRNA into PLAGL2-expressing cells led to a decrease in apoptotic cells compared with sense oligonucleotide-transfected cells. Despite the activation of DNA-HIF-1 binding activity under hypoxic conditions, neither an accumulation of HIF-1 alpha nor the activation of HIF-1 was observed following the expression of PLAGL2. These results indicate that PLAGL2 is located downstream of HIF-1 and suggest that PLAGL2 functions as a tumor suppressor in association with HIF-1.
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