scholarly journals Different Adaptive Responses to Hypoxia in Normal and Multiple Myeloma Endothelial Cells

2018 ◽  
Vol 46 (1) ◽  
pp. 203-212 ◽  
Author(s):  
Irene Filippi ◽  
Ilaria Saltarella ◽  
Carlo Aldinucci ◽  
Fabio Carraro ◽  
Roberto Ria ◽  
...  

Background/Aims: Hypoxia is a powerful stimulator of angiogenesis under physiological as well as pathological conditions. Normal endothelial cells (EC), such as human umbilical vein EC (HUVEC), are relatively affected by hypoxic insult in terms of cell survival. In contrast, EC from tumors are particularly resistant to hypoxia-induced cell death. Previous reports have shown that EC in bone marrow from multiple myeloma (MM) patients had a hypoxic phenotype, even under normoxic conditions. The aim of this study was to evaluate whether HUVEC and MMEC adapt differently to hypoxia. Methods: Cell proliferation was assessed by the CyQUANT assay. Cdc25A, p21, Bax, Bcl-xl, BNIP3, glucose transporter (GLUT)-1, monocarboxylate transporter (MCT)-4 and carbonic anhydrase (CA)IX mRNA expression was determined by qRT-PCR. HIF-1α, BNIP3, Beclin-1, LC3B, livin, Bax, Bcl-xl, p21, p62 and β-actin protein expression was analyzed by western blot. Apoptosis was determined by TUNEL assay. Silencing of BNIP3 was achieved by stealth RNA system technology. Results: While HUVEC survival was reduced after prolonged hypoxic exposure, MMEC were completely unaffected. This difference was also significant in terms of livin, cdc25A and p21 expression. Hypoxia induced apoptosis and inhibited autophagy in HUVEC, but not in MMEC, where hypoxic treatment resulted in a more sustained adaptive response. In fact, MMEC showed a more significant increase in the expression of genes regulated transcriptionally by hypoxia-inducible factor (HIF)-1α. Interestingly, they showed higher expression of BNIP3 than did HUVEC, indicating a more pronounced autophagic (and pro-survival) phenotype. The potential role of BNIP3 in EC survival was confirmed by BNIP3 siRNA experiments in HUVEC, where BNIP3 inhibition resulted in reduced cell survival and increased apoptosis. Conclusion: These findings provide further information on how hypoxia may affect EC survival and could be important for a better understanding of EC physiology under normal and pathological conditions, such as in multiple myeloma.

2002 ◽  
Vol 92 (3) ◽  
pp. 1152-1158 ◽  
Author(s):  
Scott Earley ◽  
Leif D. Nelin ◽  
Louis G. Chicoine ◽  
Benjimen R. Walker

Nitric oxide (NO) attenuates hypoxia-induced endothelin (ET)-1 expression in cultured umbilical vein endothelial cells. We hypothesized that NO similarly attenuates hypoxia-induced increases in ET-1 expression in the lungs of intact animals and reasoned that potentially reduced ET-1 levels may contribute to the protective effects of NO against the development of pulmonary hypertension during chronic hypoxia. As expected, hypoxic exposure (24 h, 10% O2) increased rat lung ET-1 peptide and prepro-ET-1 mRNA levels. Contrary to our hypothesis, inhaled NO (iNO) did not attenuate hypoxia-induced increases in pulmonary ET-1 peptide or prepro-ET-1 mRNA levels. Because of this surprising finding, we also examined the effects of NO on hypoxia-induced increases in ET peptide levels in cultured cell experiments. Consistent with the results of iNO experiments, administration of the NO donor S-nitroso- N-acetyl-penicillamine to cultured bovine pulmonary endothelial cells did not attenuate increases in ET peptide levels resulting from hypoxic (24 h, 3% O2) exposure. In additional experiments, we examined the effects of NO on the activity of a cloned ET-1 promoter fragment containing a functional hypoxia inducible factor-1 binding site in reporter gene experiments. Whereas moderate hypoxia (24 h, 3% O2) had no effect on ET-1 promoter activity, activity was increased by severe hypoxic (24 h, 0.5% O2) exposure. ET-1 promoter activity after S-nitroso- N-acetyl-penicillamine administration during severe hypoxia was greater than that in normoxic controls, although activity was reduced compared with that in hypoxic controls. These findings suggest that hypoxia-induced pulmonary ET-1 expression is unaffected by NO.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1812-1812
Author(s):  
Roberto Ria ◽  
Antonia Reale ◽  
Simona Berardi ◽  
Claudia Piccoli ◽  
Giulia Di Pietro ◽  
...  

Abstract Abstract 1812 Poster Board I-838 Multiple Myeloma (MM) is a malignancy of immunoglobulin (Ig)-synthesizing plasma cells, that home to and expand in the bone marrow. Similarly to other tumours its development is correlated to the formation of regions of hypoxia, which may be a prognostic indicator and determinant of malignant progression. It is known how in solid tumours the degree of intra-tumoral hypoxia is positively correlated with the expression of the transcription factor hypoxia-inducible factor 1 (HIF-1). HIF-1 is composed of HIF-1á and HIF-1β subunits and its production has been identified as a key element in allowing cells to adapt and survive in a hostile hypoxic environment via a variety of pathways. In hypoxia conditions, the HIF-1á subunit becomes stable and regulates the expression of target genes. When activated HIF-1á also targets those genes which are required for angiogenesis, the development of new blood vessels from an existing vascular network. Angiogenesis represents a constant hallmark of MM progression. In response to hypoxia plasma cells and stromal cells (endothelial cells [ECs], macrophages, mast cells) within the tumour express Vascular Endothelial Growth Factor (VEGF), a mitogen and survival factor specific for endothelial cells. VEGF is the major regulator of tumor-associated angiogenesis. HIF-1á directly activates transcription of the VEGF gene and this leads to autocrine signal transduction that is critical for angiogenesis. In this study we demonstrate the role of HIF-1á in MM angiogenesis. The constitutive stabilization of HIF-1á contributes to increase angiogenesis in MM. Our data show that HIF-1á is stabilized in the nucleus of MM endothelial cells (MMECs) but not in ECs of Monoclonal Gammopathies of Undetermined Significance (MGECs) and in Human Umbilical Vein ECs (HUVECs) used as controls. Western Blot and Enzyme-Linked Immunosorbent Assay (ELISA) analyses show the overexpression of HIF-1á and the proteic products of its target genes VEGF and VEGF Receptor (VEGFR)-1, in patients with relapsed disease and in MM progression but not in patients with nonactive MM (avascular phase). Moreover, immunofluorescent staining confirm the nuclear stabilization of HIF-1á in MMECs. At mRNA level all ECs express same quantity of HIF-1á mRNA, as confirmed by RT-PCR and Real-time RT-PCR, indicating that in MMECs the post-trascriptional control is affected. Finally, we show that the inhibition of HIF-1á by siRNA suppresses vessel formation in vitro and promote ECs apoptosis. Our findings indicate that HIF-1á plays an important role in MM progression and that it is correlated to the angiogenic switch from nonactive MM to active MM. Furthermore these data suggest that HIF-1á may represent a target for the MM antiangiogenic treatment. Disclosures No relevant conflicts of interest to declare.


FEBS Open Bio ◽  
2012 ◽  
Vol 2 (1) ◽  
pp. 334-338 ◽  
Author(s):  
Masaharu Hazawa ◽  
Takeshi Yasuda ◽  
Katsuko Noshiro ◽  
Ai Saotome-Nakamura ◽  
Tomoko Fukuzaki ◽  
...  

2018 ◽  
Vol 19 (8) ◽  
pp. 2286 ◽  
Author(s):  
Pi-Kai Chang ◽  
I-Chuan Yen ◽  
Wei-Cheng Tsai ◽  
Tsu-Chung Chang ◽  
Shih-Yu Lee

Rhodiola crenulata root extract (RCE) has been shown to possess protective activities against hypoxia both in vitro and in vivo. However, the effects of RCE on response to hypoxia in the endothelium remain unclear. In this study, we aimed to examine the effects of RCE in endothelial cells challenged with hypoxic exposure and to elucidate the underlying mechanisms. Human umbilical vein endothelial cells were pretreated with or without RCE and then exposed to hypoxia (1% O2) for 24 h. Cell viability, nitric oxide (NO) production, oxidative stress markers, as well as mechanistic readouts were studied. We found that hypoxia-induced cell death, impaired NO production, and oxidative stress. These responses were significantly attenuated by RCE treatment and were associated with the activation of AMP-activated kinase and extracellular signal-regulated kinase 1/2 signaling pathways. In summary, we showed that RCE protected endothelial cells from hypoxic insult and suggested that R. crenulata might be useful for the prevention of hypoxia-associated vascular dysfunction.


2021 ◽  
Vol 22 (14) ◽  
pp. 7516
Author(s):  
Ersilia Nigro ◽  
Marta Mallardo ◽  
Rita Polito ◽  
Filippo Scialò ◽  
Andrea Bianco ◽  
...  

Adiponectin and leptin are two abundant adipokines with different properties but both described such as potent factors regulating angiogenesis. AdipoRon is a small-molecule that, binding to AdipoRs receptors, acts as an adiponectin agonist. Here, we investigated the effects of AdipoRon and leptin on viability, migration and tube formation on a human in vitro model, the human umbilical vein endothelial cells (HUVEC) focusing on the expression of the main endothelial angiogenic factors: hypoxia-inducible factor 1-alpha (HIF-1α), C-X-C motif chemokine ligand 1 (CXCL1), vascular endothelial growth factor A (VEGF-A), matrix metallopeptidase 2 (MMP-2) and matrix metallopeptidase 9 (MMP-9). Treatments with VEGF-A were used as positive control. Our data revealed that, at 24 h treatment, proliferation of HUVEC endothelial cells was not influenced by AdipoRon or leptin administration; after 48 h longer exposure time, the viability was negatively influenced by AdipoRon while leptin treatment and the combination of AdipoRon+leptin produced no effects. In addition, AdipoRon induced a significant increase in complete tubular structures together with induction of cell migration while, on the contrary, leptin did not induce tube formation and inhibited cell migration; interestingly, the co-treatment with both AdipoRon and leptin determined a significant decrease of the tubular structures and cell migration indicating that leptin antagonizes AdipoRon effects. Finally, we found that the effects induced by AdipoRon administration are accompanied by an increase in the expression of CXCL1, VEGF-A, MMP-2 and MMP-9. In conclusion, our data sustain the active role of adiponectin and leptin in linking adipose tissue with the vascular endothelium encouraging the further deepening of the role of adipokines in new vessel’s formation, to candidate them as therapeutic targets.


Author(s):  
Qian Nie ◽  
Miaomiao Liu ◽  
Zhimei Zhang ◽  
Xuemei Zhang ◽  
Chao Wang ◽  
...  

Abstract Background Uric acid (UA) transporters mediate the uptake and outflow of UA, and are greatly involved in the control of UA concentrations. Glucose transporter 9 (GLUT9), one of the UA transporters, has been confirmed to be expressed in human umbilical vein endothelial cells (HUVECs). This study aimed to characterize GLUT9’s effect on intracellular UA accumulation in HUVECs in a high-UA environment and to explore the mechanism of cellular dysfunction. Methods and results HUVECs were treated with UA to establish a model of cellular dysfunction. Then, UA uptake, GLUT9 expression and endothelial nitric oxide synthase (eNOS) and reactive oxygen species (ROS) amounts were measured. UA uptake was concentration- and time-dependent, and UA treatment significantly reduced nitric oxide (NO) levels and eNOS activity. UA also upregulated pro-inflammatory molecules and GLUT9, and increased intracellular ROS amounts in HUVECs. GLUT9 knockdown reduced UA uptake and ROS content, but antioxidant treatment did not reduce GLUT9 expression. To assess the function of JAK2/STAT3 signaling, HUVECs were treated with UA, and the phosphorylation levels of JAK2, STAT3, IL-6 and SOCS3 were increased by a high concentration of UA. In addition, GLUT9 knockdown reduced the phosphorylation of JAK2/STAT3 intermediates and increased p-eNOS amounts. Conclusions GLUT9 mediated the effects of high UA levels on HUVECs by increasing the cellular uptake of UA, activating JAK2/STAT3 signaling, and reduced the production of active eNOS and NO in HUVECs.


Blood ◽  
2003 ◽  
Vol 101 (6) ◽  
pp. 2253-2260 ◽  
Author(s):  
Hong Zhang ◽  
Hasan O. Akman ◽  
Eric L. P. Smith ◽  
Jin Zhao ◽  
Joanne E. Murphy-Ullrich ◽  
...  

The transforming growth factor-β (TGF-β) family of cytokines regulates vascular development and inflammatory responses. We have recently shown that exposure of human umbilical vein endothelial cells (HUVECs) to hypoxia (1% O2) increases gene expression and bioactivation of TGF-β2 and induces its downstream effectors, Smad proteins (Smads), to associate with DNA. In the present study, we show that hypoxia-induced TGF-β2 gene expression is dependent on thrombospondin-1–mediated bioactivation of latent TGF-β. Blocking TGF-β2 but not TGF-β1 in hypoxic endothelial cell cultures inhibited induction of the TGF-β2 gene, indicating that an autocrine mechanism driven by bioactivation of TGF-β2 leads to its gene expression in hypoxic HUVECs. Exposure of HUVECs to hypoxia resulted in phosphorylation and nuclear transportation of Smad2 and Smad3 proteins as well as stimulation of transcriptional activities of Smad3 and the transcription factor hypoxia-inducible factor-1α and culminated in up-regulation of TGF-β2 gene expression. Autocrine regulation of TGF-β2 production in hypoxia may involve cross-talk between Smad3 and HIF-1α signaling pathways, and could be an important mechanism by which endothelial cells respond to hypoxic stress.


2020 ◽  
Vol 295 (15) ◽  
pp. 4796-4808 ◽  
Author(s):  
Jeff Klomp ◽  
James Hyun ◽  
Jennifer E. Klomp ◽  
Kostandin Pajcini ◽  
Jalees Rehman ◽  
...  

Endothelial cells (ECs) lining the vasculature of vertebrates respond to low oxygen (hypoxia) by maintaining vascular homeostasis and initiating adaptive growth of new vasculature through angiogenesis. Previous studies have uncovered the molecular underpinnings of the hypoxic response in ECs; however, there is a need for comprehensive temporal analysis of the transcriptome during hypoxia. Here, we sought to investigate the early transcriptional programs of hypoxic ECs by using RNA-Seq of primary cultured human umbilical vein ECs exposed to progressively increasing severity and duration of hypoxia. We observed that hypoxia modulates the expression levels of approximately one-third of the EC transcriptome. Intriguingly, expression of the gene encoding the developmental transcription factor SOX7 (SRY-box transcription factor 7) rapidly and transiently increased during hypoxia. Transcriptomic and functional analyses of ECs following SOX7 depletion established its critical role in regulating hypoxia-induced angiogenesis. We also observed that depletion of the hypoxia-inducible factor (HIF) genes, HIF1A (encoding HIF-1α) and endothelial PAS domain protein 1 (EPAS1 encoding HIF-2α), inhibited both distinct and overlapping transcriptional programs. Our results indicated a role for HIF-1α in down-regulating mitochondrial metabolism while concomitantly up-regulating glycolytic genes, whereas HIF-2α primarily up-regulated the angiogenesis transcriptional program. These results identify the concentration and time dependence of the endothelial transcriptomic response to hypoxia and an early key role for SOX7 in mediating angiogenesis.


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