scholarly journals Sprouty2 Protein Regulates Hypoxia-inducible Factor-α (HIFα) Protein Levels and Transcription of HIFα-responsive Genes

2016 ◽  
Vol 291 (32) ◽  
pp. 16787-16801 ◽  
Author(s):  
Kristin C. Hicks ◽  
Tarun B. Patel
Keyword(s):  
Hypoxia Inducible Factor ◽  
Protein Levels ◽  
Factor Α

scholarly journals HIF1α/TET1 Pathway Mediates Hypoxia-Induced Adipocytokine Promoter Hypomethylation in Human Adipocytes

Cells ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 134 ◽  
Author(s):  
Mohamed M. Ali ◽  
Shane A. Phillips ◽  
Abeer M. Mahmoud
Keyword(s):  
Dna Methylation ◽  
Interleukin 1 ◽  
Hypoxia Inducible Factor ◽  
Interferon Γ ◽  
The Body ◽  
Human Adipocytes ◽  
Protein Levels ◽  
Factor Α ◽  
Necrosis Factor

Obesity is associated with the accumulation of dysfunctional adipose tissue that secretes several pro-inflammatory cytokines (adipocytokines). Recent studies have presented evidence that adipose tissues in obese individuals and animal models are hypoxic, which may result in upregulation and stabilization of the hypoxia inducible factor HIF1α. Epigenetic mechanisms such as DNA methylation enable the body to respond to microenvironmental changes such as hypoxia and may represent a mechanistic link between obesity-associated hypoxia and upregulated inflammatory adipocytokines. The purpose of this study was to investigate the role of hypoxia in modifying adipocytokine DNA methylation and subsequently adipocytokine expression. We suggested that this mechanism is mediated via the DNA demethylase, ten-eleven translocation-1 (TET1), transcription of which has been shown to be induced by HIF1α. To this end, we studied the effect of hypoxia (2% O2) in differentiated subcutaneous human adipocytes in the presence or absence of HIF1α stabilizer (Dimethyloxalylglycine (DMOG), 500 μM), HIF1α inhibitor (methyl 3-[[2-[4-(2-adamantyl) phenoxy] acetyl] amino]-4-hydroxybenzoate, 30 μM), or TET1-specific siRNA. Subjecting the adipocytes to hypoxia significantly induced HIF1α and TET1 protein levels. Moreover, hypoxia induced global hydroxymethylation, reduced adipocytokine DNA promoter methylation, and induced adipocytokine expression. These effects were abolished by either HIF1α inhibitor or TET1 gene silencing. The major hypoxia-responsive adipocytokines were leptin, interleukin-1 (IL6), IL1β, tumor necrosis factor α (TNFα), and interferon γ (IFNγ). Overall, these data demonstrate an activation of the hydroxymethylation pathway mediated by TET1. This pathway contributes to promoter hypomethylation and gene upregulation of the inflammatory adipocytokines in adipocytes in response to hypoxia.

scholarly journals Placental but Not Heart Defects Are Associated with Elevated Hypoxia-Inducible Factor α Levels in Mice Lacking Prolyl Hydroxylase Domain Protein 2

2006 ◽  
Vol 26 (22) ◽  
pp. 8336-8346 ◽  
Author(s):  
Kotaro Takeda ◽  
Vivienne C. Ho ◽  
Hiromi Takeda ◽  
Li-Juan Duan ◽  
Andras Nagy ◽  
...  
Keyword(s):  
Heart Defects ◽  
Interventricular Septum ◽  
Hypoxia Inducible Factor ◽  
Giant Cells ◽  
Branching Morphogenesis ◽  
Mouse Development ◽  
Protein Levels ◽  
The Stability ◽  
Factor Α ◽  
Trophoblast Giant Cells

ABSTRACT PHD1, PHD2, and PHD3 are prolyl hydroxylase domain proteins that regulate the stability of hypoxia-inducible factor α subunits (HIF-α). To determine the roles of individual PHDs during mouse development, we disrupted all three Phd genes and found that Phd2 − / − embryos died between embryonic days 12.5 and 14.5 whereas Phd1 −/− or Phd3 −/− mice were apparently normal. In Phd2 − / − mice, severe placental and heart defects preceded embryonic death. Placental defects included significantly reduced labyrinthine branching morphogenesis, widespread penetration of the labyrinth by spongiotrophoblasts, and abnormal distribution of trophoblast giant cells. The expression of several trophoblast markers was also altered, including an increase in the spongiotrophoblast marker Mash2 and decreases in the labyrinthine markers Tfeb and Gcm1. In the heart, trabeculae were poorly developed, the myocardium was remarkably thinner, and interventricular septum was incompletely formed. Surprisingly, while there were significant global increases in HIF-α protein levels in the placenta and the embryo proper, there was no specific HIF-α increase in the heart. Taken together, these data indicate that among all three PHD proteins, PHD2 is uniquely essential during mouse embryogenesis.

Targeting EZH2 Ameliorates the LPS-Inhibited PDLSC Osteogenesis via Wnt/β-Catenin Pathway

2021 ◽  
pp. 1-9
Author(s):  
Mosha Cheng ◽  
Qing Zhou
Keyword(s):  
Bone Morphogenetic Protein 2 ◽  
Periodontal Ligament Stem Cells ◽  
Alizarin Red ◽  
Protein Levels ◽  
Inflammatory Conditions ◽  
Morphogenetic Protein ◽  
Related Transcription Factor ◽  
Underlying Mechanisms ◽  
Factor Α ◽  
Osteoblast Maturation

As a histone methyltransferase, enhancer of zeste homolog 2 (EZH2), suppresses osteoblast maturation and is involved in inflammation. However, the role of EZH2 in human periodontal ligament stem cells (PDLSCs) under inflammation still needs to be further investigated. This study aimed to identify the underlying mechanisms and explore the function of EZH2 in PDLSC osteogenesis under inflammation. PDLSCs were treated with sh-EZH2, DZNep or DKK1 under inflammation. The alkaline phosphatase (ALP) activity, alizarin red staining, and osteogenesis-related protein levels were analyzed. Lipopolysaccharide (LPS)-induced inflammation restrained osteogenic differentiation. Under inflammation, the upregulation of EZH2 suppressed the expression of osteogenic markers, including osteocalcin, runt-related transcription factor 2, and bone morphogenetic protein-2, the activity of ALP, and the accumulation of mineralization through the Wnt/β-catenin pathway. EZH2 knockdown inhibited the levels of proinflammatory cytokines such as interleukin-6 and tumor necrosis factor-α. These results suggested that LPS-induced overexpression of EZH2 suppressed PDLSC osteogenesis under inflammatory conditions through the Wnt/β-catenin pathway. These findings give new insights into the physiological differentiation and pathological inflammation of PDLSC osteogenesis, and provide an underlying therapeutic target for periodontitis.

scholarly journals Association of EGLN1 gene with high aerobic capacity of Peruvian Quechua at high altitude

2019 ◽  
Vol 116 (48) ◽  
pp. 24006-24011 ◽  
Author(s):  
Tom D. Brutsaert ◽  
Melisa Kiyamu ◽  
Gianpietro Elias Revollendo ◽  
Jenna L. Isherwood ◽  
Frank S. Lee ◽  
...  
Keyword(s):  
Natural Selection ◽  
Aerobic Capacity ◽  
Cellular Response ◽  
Hypoxia Inducible Factor ◽  
Total Sample ◽  
Causal Variant ◽  
Analysis Of Covariance ◽  
Adaptation To Hypoxia ◽  
Spurious Association ◽  
Factor Α

Highland native Andeans have resided at altitude for millennia. They display high aerobic capacity (VO2max) at altitude, which may be a reflection of genetic adaptation to hypoxia. Previous genomewide (GW) scans for natural selection have nominated Egl-9 homolog 1 gene (EGLN1) as a candidate gene. The encoded protein, EGLN1/PHD2, is an O2 sensor that controls levels of the Hypoxia Inducible Factor-α (HIF-α), which regulates the cellular response to hypoxia. From GW association and analysis of covariance performed on a total sample of 429 Peruvian Quechua and 94 US lowland referents, we identified 5 EGLN1 SNPs associated with higher VO2max (L⋅min−1 and mL⋅min−1⋅kg−1) in hypoxia (rs1769793, rs2064766, rs2437150, rs2491403, rs479200). For 4 of these SNPs, Quechua had the highest frequency of the advantageous (high VO2max) allele compared with 25 diverse lowland comparison populations from the 1000 Genomes Project. Genotype effects were substantial, with high versus low VO2max genotype categories differing by ∼11% (e.g., for rs1769793 SNP genotype TT = 34.2 mL⋅min−1⋅kg−1 vs. CC = 30.5 mL⋅min−1⋅kg−1). To guard against spurious association, we controlled for population stratification. Findings were replicated for EGLN1 SNP rs1769793 in an independent Andean sample collected in 2002. These findings contextualize previous reports of natural selection at EGLN1 in Andeans, and support the hypothesis that natural selection has increased the frequency of an EGLN1 causal variant that enhances O2 delivery or use during exercise at altitude in Peruvian Quechua.

scholarly journals Anti-Inflammatory Effect of Auranofin on Palmitic Acid and LPS-Induced Inflammatory Response by Modulating TLR4 and NOX4-Mediated NF-κB Signaling Pathway in RAW264.7 Macrophages

2021 ◽  
Vol 22 (11) ◽  
pp. 5920
Author(s):  
Hyun Hwangbo ◽  
Seon Yeong Ji ◽  
Min Yeong Kim ◽  
So Young Kim ◽  
Hyesook Lee ◽  
...  
Keyword(s):  
Palmitic Acid ◽  
Signaling Pathway ◽  
Chronic Inflammation ◽  
Inhibitory Effect ◽  
Simultaneous Treatment ◽  
Monocyte Chemoattractant Protein 1 ◽  
Protein Levels ◽  
Raw264.7 Macrophages ◽  
Anti Inflammatory ◽  
Factor Α

Chronic inflammation, which is promoted by the production and secretion of inflammatory mediators and cytokines in activated macrophages, is responsible for the development of many diseases. Auranofin is a Food and Drug Administration-approved gold-based compound for the treatment of rheumatoid arthritis, and evidence suggests that auranofin could be a potential therapeutic agent for inflammation. In this study, to demonstrate the inhibitory effect of auranofin on chronic inflammation, a saturated fatty acid, palmitic acid (PA), and a low concentration of lipopolysaccharide (LPS) were used to activate RAW264.7 macrophages. The results show that PA amplified LPS signals to produce nitric oxide (NO) and various cytokines. However, auranofin significantly inhibited the levels of NO, monocyte chemoattractant protein-1, and pro-inflammatory cytokines, such as interleukin (IL)-1β, tumor necrosis factor-α, and IL-6, which had been increased by co-treatment with PA and LPS. Moreover, the expression of inducible NO synthase, IL-1β, and IL-6 mRNA and protein levels increased by PA and LPS were reduced by auranofin. In particular, the upregulation of NADPH oxidase (NOX) 4 and the translocation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) induced by PA and LPS were suppressed by auranofin. The binding between the toll-like receptor (TLR) 4 and auranofin was also predicted, and the release of NO and cytokines was reduced more by simultaneous treatment with auranofin and TLR4 inhibitor than by auranofin alone. In conclusion, all these findings suggested that auranofin had anti-inflammatory effects in PA and LPS-induced macrophages by interacting with TLR4 and downregulating the NOX4-mediated NF-κB signaling pathway.

scholarly journals FBXW7 mutations reduce binding of NOTCH1, leading to cleaved NOTCH1 accumulation and target gene activation in CLL

Blood ◽  
2019 ◽  
Vol 133 (8) ◽  
pp. 830-839 ◽  
Author(s):  
Viola Close ◽  
William Close ◽  
Sabrina Julia Kugler ◽  
Michaela Reichenzeller ◽  
Deyan Yordanov Yosifov ◽  
...  
Keyword(s):  
Target Gene ◽  
Hypoxia Inducible Factor ◽  
Gene Activation ◽  
Lymphocytic Leukemia ◽  
Negative Regulator ◽  
Missense Mutations ◽  
Protein Levels ◽  
In Silico Modeling ◽  
Functional Consequences ◽  
Wd40 Domain

Abstract NOTCH1 is mutated in 10% of chronic lymphocytic leukemia (CLL) patients and is associated with poor outcome. However, NOTCH1 activation is identified in approximately one-half of CLL cases even in the absence of NOTCH1 mutations. Hence, there appear to be additional factors responsible for the impairment of NOTCH1 degradation. E3-ubiquitin ligase F-box and WD40 repeat domain containing-7 (FBXW7), a negative regulator of NOTCH1, is mutated in 2% to 6% of CLL patients. The functional consequences of these mutations in CLL are unknown. We found heterozygous FBXW7 mutations in 36 of 905 (4%) untreated CLL patients. The majority were missense mutations (78%) that mostly affected the WD40 substrate binding domain; 10% of mutations occurred in the first exon of the α-isoform. To identify target proteins of FBXW7 in CLL, we truncated the WD40 domain in CLL cell line HG-3 via clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein-9 (Cas9). Homozygous truncation of FBXW7 resulted in an increase of activated NOTCH1 intracellular domain (NICD) and c-MYC protein levels as well as elevated hypoxia-inducible factor 1-α activity. In silico modeling predicted that novel mutations G423V and W425C in the FBXW7-WD40 domain change the binding of protein substrates. This differential binding was confirmed via coimmunoprecipitation of overexpressed FBXW7 and NOTCH1. In primary CLL cells harboring FBXW7 mutations, activated NICD levels were increased and remained stable upon translation inhibition. FBXW7 mutations coincided with an increase in NOTCH1 target gene expression and explain a proportion of patients characterized by dysregulated NOTCH1 signaling.

scholarly journals Mechanical Ventilation Enhances Acinetobacter Baumannii-induced Lung Injury Through JNK Pathways

2021 ◽  
Author(s):  
Tzyy-Bin Tsay ◽  
Wan-Hsuan Chang ◽  
Ching-Mei Hsu ◽  
Lee-Wei Chen
Keyword(s):  
Mechanical Ventilation ◽  
Lung Injury ◽  
Acinetobacter Baumannii ◽  
Neutrophil Infiltration ◽  
Lavage Fluid ◽  
Protein Levels ◽  
Killing Activity ◽  
Nitrite Production ◽  
Bacteria Killing ◽  
Factor Α

Abstract Background: Patients in intensive care units (ICUs) often received broad-spectrum antibiotic treatment and Acinetobacter baumannii (A.b.) and Pseudomonas aeruginosa (P.a.) were the most common pathogens causing ventilator-associated pneumonia (VAP). This study aimed to examine the effects and mechanism of mechanical ventilation (MV) on A.b.-induced lung injury and the involvement of alveolar macrophages (AMs).Methods: C57BL/6 wild-type (WT) and c-Jun N-terminal kinase knockout (JNK1−/−) mice received MV for 3 h at 2 days after nasal instillation of A.b., P.a. (1 × 106 colony-forming unit, CFU), or normal saline.Results: Intranasal instillation of 106 CFU A.b. in C57BL/6 mice induced a significant increase in total cells and protein levels in the bronchoalveolar lavage fluid (BALF) and neutrophil infiltration in the lungs. MV after A.b. instillation increases neutrophil infiltration, interleukin (IL)-6 and vascular cell adhesion molecule (VCAM) mRNA expression in the lungs and total cells, IL-6 levels, and nitrite levels in the BALF. The killing activity of AMs against A.b. was lower than against P.a. The diminished killing activity was parallel with decreased tumor necrosis factor-α production by AMs compared with with A.b. Moreover, MV decreased the A.b. and P.a. killing activity of AMs. MV after A.b. instillation induced less total cells in the BALF and nitrite production in the serum of JNK1-/- mice than those of WT mice.Conclusion: A.b. is potent in inducing neutrophil infiltration in the lungs and total protein in the BALF. MV enhances A.b.-induced lung injury through an increase in the expression of VCAM and IL-6 levels in the BALF and a decrease in the bacteria-killing activity of AMs. A lower inflammation level in JNK1-/- mice indicates that A.b.-induced VAP causes lung injury through JNK signaling pathway in the lungs.

scholarly journals Crosstalk in oxygen homeostasis networks: SKN-1/NRF inhibits the HIF-1 hypoxia-inducible factor in Caenorhabditis elegans

2021 ◽  
Author(s):  
Dingxia Feng ◽  
Zhiwei Zhai ◽  
Zhiyong Shao ◽  
Yi Zhang ◽  
Jo Anne Powell-Coffman
Keyword(s):  
Oxidative Stress ◽  
Hypoxia Inducible Factor ◽  
Regulatory Sequences ◽  
Low Oxygen ◽  
Transcriptional Responses ◽  
C Elegans ◽  
Protein Levels ◽  
Oxygen Homeostasis ◽  
Genome Wide ◽  
A Genome

AbstractDuring development, homeostasis, and disease, organisms must balance responses that allow adaptation to low oxygen (hypoxia) with those that protect cells from oxidative stress. The evolutionarily conserved hypoxia-inducible factors are central to these processes, as they orchestrate transcriptional responses to oxygen deprivation. Here, we employ genetic strategies in C. elegans to identify stress-responsive genes and pathways that modulate the HIF-1 hypoxia-inducible factor and facilitate oxygen homeostasis. Through a genome-wide RNAi screen, we show that RNAi-mediated mitochondrial or proteasomal dysfunction increases the expression of hypoxia-responsive reporter Pnhr-57:GFP in C. elegans. Interestingly, only a subset of these effects requires hif-1. Of particular importance, we found that skn-1 RNAi increases the expression of hypoxia-responsive reporter Pnhr-57:GFP and elevates HIF-1 protein levels. The SKN-1/NRF transcription factor has been shown to promote oxidative stress resistance. We present evidence that the crosstalk between HIF-1 and SKN-1 is mediated by EGL-9, the prolyl hydroxylase that targets HIF-1 for oxygen-dependent degradation. Treatment that induces SKN-1, such as heat, increases expression of a Pegl-9:GFP reporter, and this effect requires skn-1 function and a putative SKN-1 binding site in egl-9 regulatory sequences. Collectively, these data support a model in which SKN-1 promotes egl-9 transcription, thereby inhibiting HIF-1. We propose that this interaction enables animals to adapt quickly to changes in cellular oxygenation and to better survive accompanying oxidative stress.

Anterior Diffuse Retinoblastoma: Mutational Analysis and Immunofluorescence Staining

2009 ◽  
Vol 133 (8) ◽  
pp. 1215-1218
Author(s):  
Michelle B. Crosby ◽  
G. Baker Hubbard ◽  
Brenda L. Gallie ◽  
Hans E. Grossniklaus
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor ◽  
Mutational Analysis ◽  
Hypoxia Inducible Factor ◽  
Transforming Growth Factor Β ◽  
Immunofluorescence Staining ◽  
Vascular Endothelial ◽  
Factor Α ◽  
Oxide Synthase ◽  
Endothelial Growth Factor

Abstract Retinoblastoma is the most common primary intraocular tumor of childhood and may be heritable or occur sporadically. Anterior diffuse retinoblastoma is an uncommon variant that is thought to be sporadic. We describe a child with anterior diffuse retinoblastoma who presented with a pseudohypopyon. Genetic analysis showed a germline mutation of the RB1 allele that is potentially heritable. Immunofluorescence staining was positive for transforming growth factor β and for vascular endothelial growth factor and negative for inducible nitric oxide synthase and for hypoxia inducible factor α in the tumor seeds, indicating acquisition of nonischemia-mediated survival factors of the tumor seeds in the aqueous humor.

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