scholarly journals Neuroglobin Regulates Hypoxic Response of Neuronal Cells through Hif-1α- and Nrf2-mediated Mechanism

2012 ◽  
Vol 32 (6) ◽  
pp. 1046-1060 ◽  
Author(s):  
Kalpana B Hota ◽  
Sunil K Hota ◽  
Ravi B Srivastava ◽  
Shashi B Singh
Keyword(s):  
Cytochrome C ◽  
Acute Hypoxia ◽  
Neuronal Cells ◽  
Hypoxia Inducible Factor ◽  
Redox Status ◽  
Related Factor ◽  
Cytochrome C Release ◽  
Hypoxia Inducible Factor 1 ◽  
Hypoxic Conditions ◽  
Cellular Antioxidants

Oxygen sensing in hypoxic neurons has been classically attributed to cytochrome c oxidase and prolyl-4-hydroxylases and involves stabilization of transcription factors, hypoxia-inducible factor-1 α (Hif-1 α) and nuclear factor erythroid 2-related factor 2 (Nrf2) that mediate survival responses. On the contrary, release of cytochrome c into the cytosol during hypoxic stress triggers apoptosis in neuronal cells. We, here advocate that the redox state of neuroglobin (Ngb) could regulate both Hif-1 α and Nrf2 stabilization and cytochrome c release during hypoxia. The hippocampal regions showing higher expression of Ngb were less susceptible to global hypoxia-mediated neurodegeneration. During normoxia, Ngb maintained cytochrome c in the reduced state and prevented its release from mitochondria by using cellular antioxidants. Greater turnover of oxidized cytochrome c and increased utilization of cellular antioxidants during acute hypoxia altered cellular redox status and stabilized Hif-1 α and Nrf2 through Ngb-mediated mechanism. Chronic hypoxia, however, resulted in oxidation and degradation of Ngb, accumulation of ferric ions and release of cytochrome c that triggered apoptosis. Administration of N-acetyl-cysteine during hypoxic conditions improved neuronal survival by preventing Ngb oxidation and degradation. Taken together, these results establish a role for Ngb in regulating both the survival and apoptotic mechanisms associated with hypoxia.

scholarly journals Hypoxia Rapidly Induces the Expression of Cardiomyogenic Factors in Human Adipose-Derived Adherent Stromal Cells

2019 ◽  
Vol 8 (8) ◽  
pp. 1231
Author(s):  
Choi ◽  
Moon ◽  
Jung ◽  
Lim ◽  
Lee ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stromal Cells ◽  
Hypoxia Inducible Factor ◽  
In Vivo Studies ◽  
Hypoxic Stress ◽  
Differentiation Markers ◽  
Hypoxia Inducible Factor 1 ◽  
Hypoxic Conditions ◽  
Fibroblast Growth Factor 19

Background: The efficacy of interstitial vascular fraction (SVF) transplantation in the treatment of heart disease has been proven in a variety of in vivo studies. In a previous study, we found that bone marrow-derived mesenchymal stem cells (BM-MSCs) altered their expression of several cardiomyogenic factors under hypoxic conditions. Methods: We hypothesized that hypoxia may also induce obtained adipose-derived adherent stromal cells (ADASs) from SVFs and adipose-derived stem cells (ASCs) to differentiate into cardiomyocytes and/or cells with comparable phenotypes. We examined the differentiation markers of cell lineages in ADASs and ASCs according to time by hypoxic stress and found that only ADASs expressed cardiomyogenic markers within 24 hours under hypoxic conditions in association with the expression of hypoxia-inducible factor 1-α (HIF-1α). Results: Differentially secreted proteins in a conditioned medium (CM) from ASCs and ADASs under normoxic or hypoxic conditions were detected using an antibody assay and may be associated with a dramatic increase in the expression of cardiomyogenic markers in only ADASs. Furthermore, the cardiomyogenic factors were expressed more rapidly in ADASs than in ASCs under hypoxic conditions in association with the expression of HIF-1α, and angiogenin, fibroblast growth factor-19 (FGF-19) and/or macrophage inhibitory factor (MIF) are related. Conclusions: These results provide new insights into the applicability of ADASs preconditioned by hypoxic stress in cardiac diseases.

scholarly journals Down-regulation of microRNA-31 suppresses hepatic fibrosis induced by carbon tetrachloride

2020 ◽  
Vol 18 ◽  
pp. 205873922094263
Author(s):  
Bing Deng ◽  
Detao Tang ◽  
Yong Qiang ◽  
Xiang Zheng
Keyword(s):  
Carbon Tetrachloride ◽  
Olive Oil ◽  
Hepatic Fibrosis ◽  
Biological Effects ◽  
Hypoxia Inducible Factor ◽  
Related Factor ◽  
Related Factors ◽  
Altered Expression ◽  
Cell Functions ◽  
Hypoxia Inducible Factor 1

MicroRNA-31 (miR-31) is among the most frequently altered microRNAs in human diseases, and altered expression of miR-31 has been detected in a large variety of diseases types. miR-31 could also regulate a variety of cell functions including hepatic fibrosis. Hepatic stellate cells (HSCs) are regarded as the major cell type involved in hepatic fibrosis. Male BALB/c mice (five mice per group aged 6 weeks) received 200 μL of body weight of carbon tetrachloride (10% CCl4) mixed with olive oil intraperitoneally, and the first dose was doubled. To induce hepatic fibrosis, carbon tetrachloride was injected twice a week for 4, 6, 8, and 10 weeks. Control animals were injected with an equal volume of olive oil at the same time intervals. We found that miR-31 expression and fibrosis-related factors in four hepatic fibrosis stages. However, we noted that inhibition of miR-31 was down-regulated fibrosis-related factor expression in F1–F3 stages, but no F4 stage. Thus, we hypothesize that miR-31 may mediate hepatic fibrosis. In this research, we found that inhibition of miR-31 expression significantly inhibited HSC activation. The biological function of miR-31 during HSC activation might be through targeting hypoxia-inducible factor 1-alpha inhibitor (HIF1AN). Inhibition of miR-31 can reduce the transcription factor activity of hypoxia inducible factor 1 (HIF-1) by targeting the biological effects of HIF1AN with the condition of hypoxia. In later hepatic fibrosis could be rescue combining with inhibition of miR-31 and adding heparin-binding EGF-like growth factor (HBEGF).

scholarly journals Inhibition of NGF deprivation–induced death by low oxygen involves suppression of BIMEL and activation of HIF-1

2005 ◽  
Vol 168 (6) ◽  
pp. 911-920 ◽  
Author(s):  
Liang Xie ◽  
Randall S. Johnson ◽  
Robert S. Freeman
Keyword(s):  
Cell Death ◽  
Cytochrome C ◽  
Protective Effect ◽  
Sympathetic Neurons ◽  
Hypoxia Inducible Factor ◽  
Trophic Factor ◽  
Low Oxygen ◽  
Cytochrome C Release ◽  
Targeted Deletion ◽  
Trophic Factor Deprivation

Changes in O2 tension can significantly impact cell survival, yet the mechanisms underlying these effects are not well understood. Here, we report that maintaining sympathetic neurons under low O2 inhibits apoptosis caused by NGF deprivation. Low O2 exposure blocked cytochrome c release after NGF withdrawal, in part by suppressing the up-regulation of BIMEL. Forced BIMEL expression removed the block to cytochrome c release but did not prevent protection by low O2. Exposing neurons to low O2 also activated hypoxia-inducible factor (HIF) and expression of a stabilized form of HIF-1α (HIF-1αPP→AG) inhibited cell death in normoxic, NGF-deprived cells. Targeted deletion of HIF-1α partially suppressed the protective effect of low O2, whereas deletion of HIF-1α combined with forced BIMEL expression completely reversed the ability of low O2 to inhibit cell death. These data suggest a new model for how O2 tension can influence apoptotic events that underlie trophic factor deprivation–induced cell death.

scholarly journals Differential roles of prostaglandin E-type receptors in activation of hypoxia-inducible factor 1 by prostaglandin E1in vascular-derived cells under non-hypoxic conditions

PeerJ ◽  
2013 ◽  
Vol 1 ◽  
pp. e220 ◽  
Author(s):  
Kengo Suzuki ◽  
Kenichiro Nishi ◽  
Satoshi Takabuchi ◽  
Shinichi Kai ◽  
Tomonori Matsuyama ◽  
...  
Keyword(s):  
Hypoxia Inducible Factor ◽  
Prostaglandin E ◽  
Hypoxia Inducible Factor 1 ◽  
Hypoxic Conditions

scholarly journals Evolutionary GEM: Evolution of Cytochrome c Oxidase IV Regulation in Mammals

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Joseph Brockman ◽  
Patricia M. Gray
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Hypoxia Inducible Factor ◽  
Aerobic Bacteria ◽  
Oxygen Species ◽  
Independent Manner ◽  
Hypoxia Inducible Factor 1 ◽  
Early Atmosphere ◽  
Responsive Element ◽  
Multicellular Organisms

Aerobic respiration, although metabolically advantageous in O2-rich environments, can be detrimental to the cell when O2 is not fully reduced resulting in cytotoxic reactive oxygen species (ROS) production. Cytochrome c oxidase subunit 4 (COX-4) is primarily responsible for fully reducing O2 during metabolism and exists as COX4-1 and COX4-2 isoforms. The former exists in normoxia, but is replaced by the latter in hypoxia. This change is brought about by two mechanisms, the first involving regulation by hypoxia inducible factor 1 (HIF-1), which directly upregulates COX4-2 and indirectly degrades COX4-1. The second mechanism involves an oxygen responsive element (ORE), which upregulates COX4-2 in a HIF-1 independent manner. The convergence of two unrelated pathways to regulate COX4-1 and COX4-2 would allow cells to optimize their metabolic profile within an environment experiencing varying O2, such as Earth’s early atmosphere in the case of primitive aerobic bacteria or in multicellular organisms where O2 levels vary between tissues such as lung tissue.

scholarly journals HIF-1: the knowns and unknowns of hypoxia sensing.

2004 ◽  
Vol 51 (3) ◽  
pp. 563-585 ◽  
Author(s):  
Anna Zagórska ◽  
Józef Dulak
Keyword(s):  
Transcriptional Activity ◽  
Hypoxia Inducible Factor ◽  
Hypoxia Inducible Factor 1 ◽  
Hypoxic Conditions ◽  
Oxygen Homeostasis ◽  
Wide Range ◽  
Systemic Oxygen ◽  
Prolyl Hydroxylation ◽  
Energy Deprivation ◽  
Direct Inhibitors

Hypoxia-inducible factor-1 (HIF-1) is a transcriptional activator that functions as a master regulator of cellular and systemic oxygen homeostasis. It consists of two constitutively produced subunits: HIF-1alpha and HIF-1beta. Under normoxic conditions HIF-1alpha undergoes hydroxylation at specific prolyl residues which leads to an immediate ubiquitination and subsequent proteasomal degradation of the alpha subunit. Additionally, hydroxylation of an asparaginyl residue blocks the transcriptional activity of HIF-1 due to inhibition of its interaction with co-activators. In contrast, under hypoxic conditions, abolition of prolyl hydroxylation results in HIF-1alpha stabilization, whereas the lack of asparaginyl hydroxylation allows the transcriptional activity. Additionally, the transcriptional activity may be modulated by phosphorylation or redox modification of HIF-1. Despite its name, HIF-1 is induced not only in response to reduced oxygen availability but also by other stimulants, such as nitric oxide, various growth factors, or direct inhibitors of prolyl and asparaginyl hydroxylases. Therefore, it seems to be a crucial transcription factor elicited by a wide range of stresses such as impaired oxygenation, inflammation, energy deprivation, or intensive proliferation. However, the mechanisms of normoxic activation, as well as of oxygen sensing, are not yet fully known. Further understanding of the processes that control HIF-1 activity will be crucial for the development of new diagnostic and therapeutic strategies.

A new HIF-1 alpha variant induced by zinc ion suppresses HIF-1-mediated hypoxic responses

2001 ◽  
Vol 114 (22) ◽  
pp. 4051-4061
Author(s):  
Yang-Sook Chun ◽  
Eunjoo Choi ◽  
Eun-Jin Yeo ◽  
Jong Ho Lee ◽  
Myung-Suk Kim ◽  
...  
Keyword(s):  
Nuclear Translocation ◽  
Consensus Sequence ◽  
Hypoxia Inducible Factor ◽  
Zinc Ion ◽  
Dominant Negative ◽  
Hypoxia Inducible Factor 1 ◽  
Aryl Hydrocarbon ◽  
Hypoxic Conditions ◽  
Alpha Variant ◽  
Inducible Genes

The expressions of hypoxia-inducible genes are upregulated by hypoxia-inducible factor 1 (HIF-1), which is a heterodimer of HIF-1α and HIF-1β/ARNT (aryl hydrocarbon receptor nuclear transporter). Under hypoxic conditions, HIF-1α becomes stabilized and both HIF-1α and ARNT are translocated into the nucleus and codimerized, binding to the HIF-1 consensus sequence and transactivating hypoxia-inducible genes. Other than hypoxia, cobalt and nickel, which can substitute for iron in the ferroprotein, induce the stabilization of HIF-1α and the activation of HIF-1. We found previously that, although zinc, another example of a metal substitute for iron, stabilized HIF-1α, it suppressed the formation of HIF-1 by blocking the nuclear translocation of ARNT. Here, we identify a new spliced variant of human HIF-1α that is induced by zinc. The isoform lacks the 12th exon, which produced a frame-shift and gave a shorter form of HIF-1α (557 amino acids), designated HIF-1αZ (HIF-1α induced by Zn). This moiety was found to inhibit HIF-1 activity and reduce mRNA expressions of the hypoxia-inducible genes. It blocked the nuclear translocation of ARNT but not that of endogenous HIF-1α, and was associated with ARNT in the cytosol. These results suggest that HIF-1αZ functions as a dominant-negative isoform of HIF-1 by sequestering ARNT in the cytosol. In addition, the generation of HIF-1αZ seems to be responsible for the inhibitory effects of the zinc ion on HIF-1-mediated hypoxic responses, because the expressed HIF-1αZ behaved in the same manner as zinc in terms of inhibited HIF-1 activity and ARNT translocation.

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