Postpneumonectomy lung expansion elicits hypoxia-inducible factor-1α signaling

2007 ◽  
Vol 293 (2) ◽  
pp. L497-L504 ◽  
Author(s):  
Quiyang Zhang ◽  
Dennis J. Bellotto ◽  
Priya Ravikumar ◽  
Orson W. Moe ◽  
Richard T. Hogg ◽  
...  
Keyword(s):  
Compensatory Growth ◽  
Nuclear Protein ◽  
Hypoxia Inducible Factor ◽  
Erythropoietin Receptor ◽  
Growth And Remodeling ◽  
Significant Elevation ◽  
Protein Levels ◽  
Lung Expansion ◽  
The Right

We ( 42 ) previously reported differential regulation of hypoxia-inducible factors (HIF-1α, -2α, and -3α) mRNA in canine lungs during normal maturation and postpneumonectomy (PNX) compensatory growth in the absence of overt hypoxia. To test the hypothesis that lung expansion activates HIF signaling, we replaced the right lung of six adult foxhounds with inflated custom-shaped silicone prosthesis to keep the mediastinum in the midline and minimize lateral expansion of the remaining lung. After 3 wk of recovery and stabilization of perfusion, the prosthesis was acutely deflated in three animals, causing the remaining lung to expand by 114%. In three other animals, the prosthesis remained inflated. Three days following deflation, we observed significant elevation in the mRNA and nuclear protein levels of HIF-1α (∼60%) as well as activation of its transcriptional regulator, the serine/threonine protein kinase B (phospho-Akt-to-total Akt ratio, 124%), and the mRNA and protein levels of its downstream targets, erythropoietin receptor (71–183%) as well as VEGF (33–58%) compared with the pre-PNX control lung from the same animal. The mRNA of HIF-2α, HIF-3α, and VEGF receptors did not change with acute deflation. We conclude that in vivo lung expansion by post-PNX deflation of space-occupying prosthesis elicits coordinated activation of HIF-1α signaling in adult lungs. This pathway could play an important role in mediating lung growth and remodeling during maturation and post-PNX compensation.

scholarly journals Separating in vivo mechanical stimuli for postpneumonectomy compensation: physiological assessment

2013 ◽  
Vol 114 (1) ◽  
pp. 99-106 ◽  
Author(s):  
D. Merrill Dane ◽  
Cuneyt Yilmaz ◽  
Aaron S. Estrera ◽  
Connie C. W. Hsia
Keyword(s):  
Wound Healing ◽  
Lung Volume ◽  
Mechanical Stimuli ◽  
Lung Growth ◽  
Growth And Remodeling ◽  
Lung Expansion ◽  
Physiological Assessment ◽  
The Right ◽  
Sustained Increase

Following right pneumonectomy (PNX), the remaining lung expands and its perfusion doubles. Tissue and microvascular mechanical stresses are putative stimuli for initiating compensatory lung growth and remodeling, but their relative contributions to overall compensation remain uncertain. To temporally isolate the stimuli related to post-PNX lung expansion (parenchyma deformation) from those related to the sustained increase in perfusion (microvascular distention and shear), we replaced the right lung of adult dogs with a custom-shaped inflated prosthesis. Following stabilization of perfusion and wound healing 4 mo later, the prosthesis was either acutely deflated (DEF group) or kept inflated (INF group). Physiological studies were performed pre-PNX, 4 mo post-PNX (inflated prosthesis, INF1), and again 4 mo postdeflation (DEF) compared with controls with simultaneous INF prosthesis (INF2). Perfusion to the remaining lung increased ∼76–113% post-PNX (INF1 and INF2) and did not change postdeflation. Post-PNX (INF prosthesis) end-expiratory lung volume (EELV) and lung and membrane diffusing capacities (DlCO and DmCO) at a given perfusion were 25–40% below pre-PNX baseline. In the INF group EELV, DlCO and DmCO remained stable or declined slightly with time. In contrast, all of these parameters increased significantly after deflation and were 157%, 26%, and 47%, respectively, above the corresponding control values (INF2). Following delayed deflation, lung expansion accounted for 44%-48% of total post-PNX compensatory increase in exercise DlCO and peak O2 uptake; the remainder fraction is likely attributable to the increase in perfusion. Results suggest that expansion-related parenchyma mechanical stress and perfusion-related microvascular stress contribute in equal proportions to post-PNX alveolar growth and remodeling.

scholarly journals The PPARγ ligand rosiglitazone attenuates hypoxia-induced endothelin signaling in vitro and in vivo

2011 ◽  
Vol 301 (6) ◽  
pp. L881-L891 ◽  
Author(s):  
Bum-Yong Kang ◽  
Jennifer M. Kleinhenz ◽  
Tamara C. Murphy ◽  
C. Michael Hart
Keyword(s):  
Transcription Factors ◽  
Hypoxia Inducible Factor ◽  
Cell Counting ◽  
Mouse Lung ◽  
Therapeutic Effects ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Protein Levels

Peroxisome proliferator-activated receptor (PPAR) γ activation attenuates hypoxia-induced pulmonary hypertension (PH) in mice. The current study examined the hypothesis that PPARγ attenuates hypoxia-induced endothelin-1 (ET-1) signaling to mediate these therapeutic effects. To test this hypothesis, human pulmonary artery endothelial cells (HPAECs) were exposed to normoxia or hypoxia (1% O2) for 72 h and treated with or without the PPARγ ligand rosiglitazone (RSG, 10 μM) during the final 24 h of exposure. HPAEC proliferation was measured with MTT assays or cell counting, and mRNA and protein levels of ET-1 signaling components were determined. To explore the role of hypoxia-activated transcription factors, selected HPAECs were treated with inhibitors of hypoxia-inducible factor (HIF)-1α (chetomin) or nuclear factor (NF)-κB (caffeic acid phenethyl ester, CAPE). In parallel studies, male C57BL/6 mice were exposed to normoxia (21% O2) or hypoxia (10% O2) for 3 wk with or without gavage with RSG (10 mg·kg−1·day−1) for the final 10 days of exposure. Hypoxia increased ET-1, endothelin-converting enzyme-1, and endothelin receptor A and B levels in mouse lung and in HPAECs and increased HPAEC proliferation. Treatment with RSG attenuated hypoxia-induced activation of HIF-1α, NF-κB activation, and ET-1 signaling pathway components. Similarly, treatment with chetomin or CAPE prevented hypoxia-induced increases in HPAEC ET-1 mRNA and protein levels. These findings indicate that PPARγ activation attenuates a program of hypoxia-induced ET-1 signaling by inhibiting activation of hypoxia-responsive transcription factors. Targeting PPARγ represents a novel therapeutic strategy to inhibit enhanced ET-1 signaling in PH pathogenesis.

scholarly journals Tumor protein D52 is upregulated in oral squamous carcinoma cells under hypoxia in a hypoxia-inducible-factor-independent manner and is involved in cell death resistance

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuzo Abe ◽  
Yoshiki Mukudai ◽  
Mai Kurihara ◽  
Asami Houri ◽  
Junichiro Chikuda ◽  
...  
Keyword(s):  
Hypoxia Inducible Factor ◽  
Squamous Carcinoma ◽  
Cancer Therapeutics ◽  
Tumor Xenograft ◽  
Independent Manner ◽  
Protein Levels ◽  
Squamous Carcinoma Cells ◽  
Oral Squamous Carcinoma

Abstract Background Tumor protein D52 (TPD52) reportedly plays an important role in the proliferation and metastasis of various cancer cells, including oral squamous cell carcinoma (OSCC) cells, and is expressed strongly at the center of the tumor, where the microenvironment is hypoxic. Thus, the present study investigated the roles of TPD52 in the survival and death of OSCC cells under hypoxia, and the relationship with hypoxia-inducible factor (HIF). We examined the expression of TPD52 in OSCC cells under hypoxic conditions and analyzed the effects of HIF on the modulation of TPD52 expression. Finally, the combinational effects of TPD52 knockdown and HIF inhibition were investigated both in vitro and in vivo. Results The mRNA and protein levels of TPD52 increased in OSCC cells under hypoxia. However, the increase was independent of HIF transcription. Importantly, the observation was due to upregulation of mRNA stability by binding of mRNA to T-cell intercellular antigen (TIA) 1 and TIA-related protein (TIAR). Simultaneous knockdown of TPD52 and inhibition of HIF significantly reduced cell viability. In addition, the in vivo tumor-xenograft experiments showed that TPD52 acts as an autophagy inhibitor caused by a decrease in p62. Conclusions This study showed that the expression of TPD52 increases in OSCC cells under hypoxia in a HIF-independent manner and plays an important role in the proliferation and survival of the cells in concordance with HIF, suggesting that novel cancer therapeutics might be led by TPD52 suppression.

scholarly journals Protective effects of piperine on the retina of mice with streptozotocin-induced diabetes by suppressing HIF-1/VEGFA pathway and promoting PEDF expression

2021 ◽  
Vol 14 (5) ◽  
pp. 656-665
Author(s):  
Pu Zhang ◽  
◽  
Yao Tan ◽  
Ling Gao ◽  
◽  
...  
Keyword(s):  
Protein Level ◽  
Pigment Epithelium ◽  
Hypoxia Inducible Factor ◽  
Protective Effects ◽  
Protein Levels ◽  
Chemical Hypoxia ◽  
Diabetic Retina ◽  
Streptozotocin Induced Diabetes

AIM: To evaluate the protective mechanisms of piperine in the retina of mice with streptozotocin-induced diabetes. METHODS: In experiments in vitro, stimulation by chemical hypoxia was established in ARPE-19 cells. Then, the expression of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor A (VEGFA), and pigment epithelium-derived factor (PEDF) was assessed at the mRNA and protein levels. In experiments in vivo, diabetes mellitus was established by intraperitoneally injecting 150 mg/kg streptozotocin once. After 3wk of the onset of diabetes, 15 mg/kg piperine was intraperitoneally injected once daily for 1 or 3wk. Then, the retinal morphology and mRNA and protein expression were assessed. RESULTS: In hypoxia, 1-100 μmol/L piperine significantly decreased the expression of VEGFA mRNA and increased the expression of PEDF mRNA without affecting HIF-1α mRNA. Meanwhile, 100 μmol/L piperine substantially decreased the protein level of VEGFA and increased the protein level of PEDF. The HIF-1α protein level was also hampered by piperine. In the diabetic retina of mice, the morphological damage was alleviated by piperine. Likewise, the retinal vascular leakage was substantially decreased by piperine. Further, the protein levels of HIF-1α and VEGFA were significantly reduced by piperine. Moreover, the level of the antiangiogenic factor of PEDF dramatically increased by piperine. CONCLUSION: Piperine may exert protective effects on the retina of mice with diabetes via regulating the pro-antiangiogenic homeostasis composed of HIF-1/VEGFA and PEDF.

scholarly journals Tumor Protein D52 Is Upregulated in Oral Squamous Carcinoma Cells Under Hypoxia in a Hypoxia-inducible-factor-independent Manner and Is Involved in Cell Death Resistance

2021 ◽  
Author(s):  
Yuzo Abe ◽  
Yoshiki Mukudai ◽  
Mai Kurihara ◽  
Asami Houri ◽  
Junichiro Chikuda ◽  
...  
Keyword(s):  
Hypoxia Inducible Factor ◽  
Squamous Carcinoma ◽  
Cancer Therapeutics ◽  
Tumor Xenograft ◽  
Independent Manner ◽  
Protein Levels ◽  
Squamous Carcinoma Cells ◽  
Oral Squamous Carcinoma

Abstract Background. Tumor protein D52 (TPD52) reportedly plays an important role in the proliferation and metastasis of various cancer cells, including oral squamous cell carcinoma (OSCC) cells, and is expressed strongly at the center of the tumor, where the microenvironment is hypoxic. Thus, the present study investigated the roles of TPD52 in the survival and death of OSCC cells under hypoxia, and the relationship with hypoxia-inducible factor (HIF). We examined the expression of TPD52 in OSCC cells under hypoxic conditions and analyzed the effects of HIF on the modulation of TPD52 expression. Finally, the combinational effects of TPD52 knockdown and HIF inhibition were investigated both in vitro and in vivo.Results. The mRNA and protein levels of TPD52 increased in OSCC cells under hypoxia. However, the increase was independent of HIF transcription. Importantly, the observation was due to upregulation of mRNA stability by binding of mRNA to T-cell intercellular antigen (TIA) 1 and TIA-related protein (TIAR). Simultaneous knockdown of TPD52 and inhibition of HIF significantly reduced cell viability. In addition, the in vivo tumor-xenograft experiments showed that TPD52 acts as an autophagy inhibitor caused by a decrease in p62.Conclusions. This study showed that the expression of TPD52 increases in OSCC cells under hypoxia in a HIF-independent manner and plays an important role in the proliferation and survival of the cells in concordance with HIF, suggesting that novel cancer therapeutics might be led by TPD52 suppression.

scholarly journals Satellite cell-mediated angiogenesis in vitro coincides with a functional hypoxia-inducible factor pathway

2009 ◽  
Vol 296 (6) ◽  
pp. C1321-C1328 ◽  
Author(s):  
R. P. Rhoads ◽  
R. M. Johnson ◽  
C. R. Rathbone ◽  
X. Liu ◽  
C. Temm-Grove ◽  
...  
Keyword(s):  
Gene Expression ◽  
Satellite Cell ◽  
Hypoxia Inducible Factor ◽  
Collagen Gel ◽  
Culture Conditions ◽  
Cell Physiology ◽  
Vegf Gene ◽  
Protein Levels

Muscle regeneration involves the coordination of myogenesis and revascularization to restore proper muscle function. Myogenesis is driven by resident stem cells termed satellite cells (SC), whereas angiogenesis arises from endothelial cells and perivascular cells of preexisting vascular segments and the collateral vasculature. Communication between myogenic and angiogenic cells seems plausible, especially given the number of growth factors produced by SC. To characterize these interactions, we developed an in vitro coculture model composed of rat skeletal muscle SC and microvascular fragments (MVF). In this system, isolated epididymal MVF suspended in collagen gel are cultured over a rat SC monolayer culture. In the presence of SC, MVF exhibit greater indices of angiogenesis than MVF cultured alone. A positive dose-dependent effect of SC conditioned medium (CM) on MVF growth was observed, suggesting that SC secrete soluble-acting growth factor(s). Next, we specifically blocked VEGF action in SC CM, and this was sufficient to abolish satellite cell-induced angiogenesis. Finally, hypoxia-inducible factor-1α (HIF-1α), a transcriptional regulator of VEGF gene expression, was found to be expressed in cultured SC and in putative SC in sections of in vivo stretch-injured rat muscle. Hypoxic culture conditions increased SC HIF-1α activity, which was positively associated with SC VEGF gene expression and protein levels. Collectively, these initial observations suggest that a heretofore unexplored aspect of satellite cell physiology is the initiation of a proangiogenic program.

scholarly journals Identification of a region on hypoxia-inducible-factor prolyl 4-hydroxylases that determines their specificity for the oxygen degradation domains

2007 ◽  
Vol 408 (2) ◽  
pp. 231-240 ◽  
Author(s):  
Diego Villar ◽  
Alicia Vara-Vega ◽  
Manuel O. Landázuri ◽  
Luis Del Peso
Keyword(s):  
Transcription Factors ◽  
Tertiary Structure ◽  
Hypoxia Inducible Factor ◽  
Domain Swapping ◽  
Dependent Manner ◽  
Low Oxygen ◽  
Protein Levels ◽  
The Stability

HIFs [hypoxia-inducible (transcription) factors] are essential for the induction of an adaptive gene expression programme under low oxygen partial pressure. The activity of these transcription factors is mainly determined by the stability of the HIFα subunit, which is regulated, in an oxygen-dependent manner, by a family of three prolyl 4-hydroxylases [EGLN1–EGLN3 (EGL nine homologues 1–3)]. HIFα contains two, N- and C-terminal, independent ODDs (oxygen-dependent degradation domains), namely NODD and CODD, that, upon hydroxylation by the EGLNs, target HIFα for proteasomal degradation. In vitro studies indicate that each EGLN shows a differential preference for ODDs, However, the sequence determinants for such specificity are unknown. In the present study we showed that whereas EGLN1 and EGLN2 acted upon any of these ODDs to regulate HIF1α protein levels and activity in vivo, EGLN3 only acted on the CODD. With the aim of identifying the region within EGLNs responsible for their differential substrate preference, we investigated the activity and binding pattern of different EGLN deletions and chimaeric constructs generated by domain swapping between EGLN1 and EGLN3. These studies revealed a region of 97 residues that was sufficient to confer the characteristic substrate binding observed for each EGLN. Within this region, we identified the minimal sequence (EGLN1 residues 236–252) involved in substrate discrimination. Importantly, mapping of these sequences on the EGLN1 tertiary structure indicates that substrate specificity is determined by a region relatively remote from the catalytic site.

scholarly journals Androgens regulate ovarian gene expression by balancing Ezh2-Jmjd3 mediated H3K27me3 dynamics

PLoS Genetics ◽  
2021 ◽  
Vol 17 (3) ◽  
pp. e1009483
Author(s):  
Sambit Roy ◽  
Binbin Huang ◽  
Niharika Sinha ◽  
Jianrong Wang ◽  
Aritro Sen
Keyword(s):  
Gene Expression ◽  
Ovarian Function ◽  
Critical Role ◽  
Hypoxia Inducible Factor ◽  
Female Fertility ◽  
Epigenetic Mark ◽  
Knockout Mouse Model ◽  
Protein Levels ◽  
Ovarian Granulosa Cell

Conventionally viewed as male hormone, androgens play a critical role in female fertility. Although androgen receptors (AR) are transcription factors, to date very few direct transcriptional targets of ARs have been identified in the ovary. Using mouse models, this study provides three critical insights about androgen-induced gene regulation in the ovary and its impact on female fertility. First, RNA-sequencing reveals a number of genes and biological processes that were previously not known to be directly regulated by androgens in the ovary. Second, androgens can also influence gene expression by decreasing the tri-methyl mark on lysine 27 of histone3 (H3K27me3), a gene silencing epigenetic mark. ChIP-seq analyses highlight that androgen-induced modulation of H3K27me3 mark within gene bodies, promoters or distal enhancers have a much broader impact on ovarian function than the direct genomic effects of androgens. Third, androgen-induced decrease of H3K27me3 is mediated through (a) inhibiting the expression and activity of Enhancer of Zeste Homologue 2 (EZH2), a histone methyltransferase that promotes tri-methylation of K27 and (b) by inducing the expression of a histone demethylase called Jumonji domain containing protein-3 (JMJD3/KDM6B), responsible for removing the H3K27me3 mark. Androgens through the PI3K/Akt pathway, in a transcription-independent fashion, increase hypoxia-inducible factor 1 alpha (HIF1α) protein levels, which in turn induce JMJD3 expression. Furthermore, proof of concept studies involving in vivo knockdown of Ar in the ovary and ovarian (granulosa) cell-specific Ar knockout mouse model show that ARs regulate the expression of key ovarian genes through modulation of H3K27me3.

scholarly journals Propofol Disrupts Aerobic Glycolysis in Colorectal Cancer Cells via Inactivation of the NMDAR-CAMKII-ERK Pathway

2018 ◽  
Vol 46 (2) ◽  
pp. 492-504 ◽  
Author(s):  
Xiangyuan Chen ◽  
Qichao Wu ◽  
Pengfei Sun ◽  
Yanjun Zhao ◽  
Minmin Zhu ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Glucose Metabolism ◽  
Cancer Cells ◽  
Aerobic Glycolysis ◽  
Hypoxia Inducible Factor ◽  
Xenograft Model ◽  
Erk Pathway ◽  
Protein Levels ◽  
Colorectal Cancer Cells

Background/Aims: To investigate the effect of propofol on glucose metabolism in colorectal cancer cells and in an in vivo xenograft model. Methods: Glucose metabolism was assessed by measuring the extracellular acidification rate in HT29 and SW480 colorectal cancer cells. Quantitative real-time PCR and western blot analyses were used to detect mRNA and protein levels, respectively. Intracellular calcium was assessed by using a Fluo-3 AM fluorescence kit. Micro-positron emission tomography/computed tomography (microPET/CT) imaging was used to analyze glucose metabolism in the tumors of the xenograft model. Results: Propofol exposure induced a dose-dependent decrease of aerobic glycolysis in HT29 and SW480 colorectal cancer cells. MicroPET/CT indicated that propofol also inhibited 18F-FDG uptake in the xenograft model. In addition, hypoxia-inducible factor 1α (HIF1α) was also reduced by propofol dose-dependently. Propofol repressed the NMDAR-CAMKII-ERK pathway to inactivate HIF1α and therefore reduced glycolysis. Conclusion: Propofol inhibited aerobic glycolysis in colorectal cancer cells through the inactivation of the NMDAR-CAMKII-ERK pathway, which may facilitate a better understanding of the use of propofol in the clinical setting.

20-HETE can act as a nonhypoxic regulator of HIF-1α in human microvascular endothelial cells

2009 ◽  
Vol 297 (2) ◽  
pp. H602-H613 ◽  
Author(s):  
Austin M. Guo ◽  
Gloria Scicli ◽  
Ju Sheng ◽  
John C. Falck ◽  
Paul A. Edwards ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Nadph Oxidase ◽  
Hypoxia Inducible Factor ◽  
Neutralizing Antibody ◽  
Dienoic Acid ◽  
Erythropoietin Receptor ◽  
Microvascular Endothelial Cells ◽  
Protein Levels ◽  
Diphenylene Iodonium ◽  
Microvascular Endothelial

20-HETE increases the expression of VEGF in human dermal microvascular endothelial cells (ECs). Since VEGF is regulated by hypoxia inducible factor (HIF)-1, we studied whether 20-HETE also upregulates HIF-1α using the stable 20-HETE analog 20-hydroxyeicosa-5( Z),14( Z)dienoic acid (WIT003; 1–10 μM) and found that it induced a marked increase in HIF-1α protein levels. The increases in VEGF after the addition of WIT003 preceded the changes in HIF-1α, and the increases in HIF-1α were prevented by a VEGF neutralizing antibody. This suggests that 20-HETE first causes increases in VEGF, which then, in turn, cause the upregulation of HIF-1α. Stimulation with exogenously added VEGF also led to an upregulation of HIF-1α. Incubation with the MEK1/ERK1/2 inhibitor U-0126 (10 μM) completely abolished the increases in VEGF and thus HIF-1α, suggesting the involvement of ERK1/2 activation. The addition of WIT003 resulted in a rapid and sustained increase in superoxide formation. When WIT003 was added in the presence of the nitric oxide (NO) synthase (NOS) inhibitor N-nitro-l-arginine, no changes in superoxide, VEGF, or HIF-1α were observed. This suggests that NOS is responsible for the early changes in superoxide induced by WIT003. Furthermore, WIT003 induced the expression of the NADPH oxidase subunit p47 phox in ECs before the increases in HIF-1α. Incubation with polyethylene glycol-superoxide dismutase (400 U/ml), apocynin (100 μM), diphenylene iodonium (10 μM), or p47 phox downregulation with small interfering (si)RNA all inhibited the increases in HIF-1α expression. This indicates that the early changes in superoxide lead to VEGF increases and thereby NADPH oxidase-dependent superoxide production, which is required for HIF-1α upregulation. We also found that the higher HIF-1α expression induced by WIT003 was accompanied by higher expression of erythropoietin receptor and angiopoietin-2 proteins. These increases were caused by HIF-1α because their levels were markedly decreased by siRNA downregulation of HIF-1α. 20-HETE may be a novel nonhypoxic regulator of HIF-1α and HIF-1α-regulated genes in ECs.

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