Matriptase-2 (TMPRSS6) is directly up-regulated by hypoxia inducible factor-1: identification of a hypoxia-responsive element in the TMPRSS6 promoter region

2012 ◽  
Vol 393 (6) ◽  
pp. 535-540 ◽  
Author(s):  
Eva Maurer ◽  
Michael Gütschow ◽  
Marit Stirnberg

Abstract The type II transmembrane serine protease matriptase-2 (TMPRSS6) down-regulates the expression of hepcidin, the main regulator of systemic iron homeostasis, and increases in this way iron plasma levels. Matriptase-2 is up-regulated under hypoxic conditions, providing a new link between hypoxia signaling and iron homeostasis. In this study, we have characterized the TMPRSS6 promoter region and identified a functional hypoxia-responsive element (HRE). Mutations of the hypoxia inducible factor (HIF)-binding site located within the HRE abrogate HIF-1α-dependent induction of TMPRSS6 expression. The action of HIF-1α on TMPRSS6 promoter activity reveals a new regulative element for the suppression of hepcidin synthesis.

2021 ◽  
Vol 22 (23) ◽  
pp. 13046
Author(s):  
Cinthia C. Alves ◽  
Eduardo A. Donadi ◽  
Silvana Giuliatti

Human Antigen Leukocyte-G (HLA-G) gene encodes an immune checkpoint molecule that has restricted tissue expression in physiological conditions; however, the gene may be induced in hypoxic conditions by the interaction with the hypoxia inducible factor-1 (HIF1). Hypoxia regulatory elements (HRE) located at the HLA-G promoter region and at exon 2 are the major HIF1 target sites. Since the G allele of the −964G > A transversion induces higher HLA-G expression when compared to the A allele in hypoxic conditions, here we analyzed HIF1-HRE complex interaction at the pair-atom level considering both −964G > A polymorphism alleles. Mouse HIF2 dimer crystal (Protein Data Bank ID: 4ZPK) was used as template to perform homology modelling of human HIF1 quaternary structure using MODELLER v9.14. Two 3D DNA structures were built from 5′GCRTG’3 HRE sequence containing the −964G/A alleles using x3DNA. Protein-DNA docking was performed using the HADDOCK v2.4 server, and non-covalent bonds were computed by DNAproDB server. Molecular dynamic simulation was carried out per 200 ns, using Gromacs v.2019. HIF1 binding in the HRE containing −964G allele results in more hydrogen bonds and van der Waals contact formation than HRE with −964A allele. Protein-DNA complex trajectory analysis revealed that HIF1-HRE-964G complex is more stable. In conclusion, HIF1 binds in a more stable and specific manner at the HRE with G allele.


2020 ◽  
Vol 6 (3) ◽  
pp. 27 ◽  
Author(s):  
Dominik A. Barth ◽  
Felix Prinz ◽  
Julia Teppan ◽  
Katharina Jonas ◽  
Christiane Klec ◽  
...  

Hypoxia is dangerous for oxygen-dependent cells, therefore, physiological adaption to cellular hypoxic conditions is essential. The transcription factor hypoxia-inducible factor (HIF) is the main regulator of hypoxic metabolic adaption reducing oxygen consumption and is regulated by gradual von Hippel-Lindau (VHL)-dependent proteasomal degradation. Beyond physiology, hypoxia is frequently encountered within solid tumors and first drugs are in clinical trials to tackle this pathway in cancer. Besides hypoxia, cancer cells may promote HIF expression under normoxic conditions by altering various upstream regulators, cumulating in HIF upregulation and enhanced glycolysis and angiogenesis, altogether promoting tumor proliferation and progression. Therefore, understanding the underlying molecular mechanisms is crucial to discover potential future therapeutic targets to evolve cancer therapy. Long non-coding RNAs (lncRNA) are a class of non-protein coding RNA molecules with a length of over 200 nucleotides. They participate in cancer development and progression and might act as either oncogenic or tumor suppressive factors. Additionally, a growing body of evidence supports the role of lncRNAs in the hypoxic and normoxic regulation of HIF and its subunits HIF-1α and HIF-2α in cancer. This review provides a comprehensive update and overview of lncRNAs as regulators of HIFs expression and activation and discusses and highlights potential involved pathways.


2012 ◽  
Vol 32 (6) ◽  
pp. 1046-1060 ◽  
Author(s):  
Kalpana B Hota ◽  
Sunil K Hota ◽  
Ravi B Srivastava ◽  
Shashi B Singh

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.


2006 ◽  
Vol 281 (35) ◽  
pp. 25703-25711 ◽  
Author(s):  
Donghoon Yoon ◽  
Yves D. Pastore ◽  
Vladimir Divoky ◽  
Enli Liu ◽  
Agnieszka E. Mlodnicka ◽  
...  

2019 ◽  
Vol 8 (8) ◽  
pp. 1231
Author(s):  
Choi ◽  
Moon ◽  
Jung ◽  
Lim ◽  
Lee ◽  
...  

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.


2019 ◽  
Vol 393 (3) ◽  
pp. 511-520
Author(s):  
Erzsébet Pászti-Gere ◽  
Gergely Szombath ◽  
Michael Gütschow ◽  
Torsten Steinmetzer ◽  
András Székács

Abstract Matriptase-2 (MT-2) is a type II transmembrane serine protease and predominantly attached to the surface of hepatocytes. MT-2 decreases the production of hepcidin, a key regulator of iron homeostasis. In this study, the effects of four 3-amidinophenylalanine-derived combined matriptase-1/matriptase-2 (MT-1/2) inhibitors (MI-432, MI-441, MI-460, and MI-461) on hepcidin production were investigated in hepatocyte mono- and hepatocyte-Kupffer cell co-cultures. In MI-461-treated cell cultures, the extracellular hydrogen peroxide contents and the interleukin-6 and -8 (IL-6 and IL-8) levels were determined and compared to controls. Hepcidin overproduction was observed in hepatocytes upon treatment with MI-432, MI-441 and MI-461 at 50 μM. In contrast, extracellular hydrogen peroxide levels were not elevated significantly after matriptase inhibition with MI-461. Furthermore, MI-461 did not induce increases in IL-6 and IL-8 levels in these hepatic models. A model of the binding mode of inhibitor MI-461 in complex with MT-2 revealed numerous polar contacts contributing to the nanomolar potency of this compound. Based on the in vitro data on hepcidin regulation, treatment with MI-461 might be valuable in pathological states of iron metabolism without causing excessive oxidative stress.


2010 ◽  
Vol 21 (21) ◽  
pp. 3630-3638 ◽  
Author(s):  
Ian P. Newton ◽  
Niall S. Kenneth ◽  
Paul L. Appleton ◽  
Inke Näthke ◽  
Sonia Rocha

The tumor suppressor adenomatous polyposis coli (APC) is mutated in the majority of colorectal cancers and is best known for its role as a scaffold in a Wnt-regulated protein complex that determines the availability of β-catenin. Another common feature of solid tumors is the presence of hypoxia as indicated by the up-regulation of hypoxia-inducible factors (HIFs) such as HIF-1α. Here, we demonstrate a novel link between APC and hypoxia and show that APC and HIF-1α antagonize each other. Hypoxia results in reduced levels of APC mRNA and protein via a HIF-1α–dependent mechanism. HIF-1α represses the APC gene via a functional hypoxia-responsive element on the APC promoter. In contrast, APC-mediated repression of HIF-1α requires wild-type APC, low levels of β-catenin, and nuclear factor-κB activity. These results reveal down-regulation of APC as a new mechanism that contributes to the survival advantage induced by hypoxia and also show that loss of APC mutations produces a survival advantage by mimicking hypoxic conditions.


PeerJ ◽  
2013 ◽  
Vol 1 ◽  
pp. e220 ◽  
Author(s):  
Kengo Suzuki ◽  
Kenichiro Nishi ◽  
Satoshi Takabuchi ◽  
Shinichi Kai ◽  
Tomonori Matsuyama ◽  
...  

Author(s):  
Joseph Brockman ◽  
Patricia M. Gray

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.


2004 ◽  
Vol 51 (3) ◽  
pp. 563-585 ◽  
Author(s):  
Anna Zagórska ◽  
Józef Dulak

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.


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