Transcriptome Analysis of Gills Provides Insights Into Translation Changes Under Hypoxic Stress and Reoxygenation in Golden Pompano, Trachinotus ovatus (Linnaeus 1758)

Golden pompano (Trachinotus ovatus) is one of the most economically critical marine fish in South China. Low oxygen stress has resulted in substantial economic losses to the aquaculture of T. ovatus. However, the molecular responses of fish gills to hypoxia challenge remain unclear. To understand the mechanism underlying adaption to hypoxia, we analyzed the transcriptome of T. ovatus gills in response to hypoxic stress in the normal oxygen group, hypoxic group, and hypoxia treatment after oxygen recovery group. This study found that hypoxia for 8 h was the critical time of hypoxic stress and corresponded to the largest number of differentially expressed genes. After hypoxic stress, genes for chemokines, chemokine receptors, interleukins, complement factors, and other cytokines were significantly downregulated, which may be why fish are vulnerable to pathogen infection in a hypoxic environment. According to a Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, many downregulated genes were significantly enriched in the steroid biosynthesis, focal adhesion, and the extracellular matrix (ECM)-receptor interaction signal pathways, which affected cell signal transduction, adhesion, and apoptosis. Compared with the hypoxic group, the amounts of upregulated genes related to phagocytosis and protein degradation were upregulated in the dissolved oxygen recovery group. These results indicated that after the recovery of dissolved oxygen, the fish body repaired the stress-induced damage by rapidly removing misfolded proteins. These findings provide a better understanding of the hypoxia response mechanism of fish and represent a useful resource for the genetic breeding of T. ovatus.

A Modificatory Screening Protocol for ARDS in Patients with Respiratory Support Based on SpO2 and FiO2

Background: A large number of recent studies have confirmed that the pulse oximetric saturation (SpO2)/fraction of inspired oxygen (FiO2) ratio (SFR) correlate well with PaO2/FiO2 ratio (PFR). However, whether SFR can replace PFR for the diagnosis and evaluate the severity of ARDS patients with advanced respiratory support is unclearly. The purpose of this study is to explore potential value of SFR ratio as a new diagnostic tool for ARDS by establishing new processes in patients who require high levels of oxygen support.Methods: 341 patients were included in this study, SFR and PFR values were recorded in the same time. 161 patients were used to establish the model, and 180 patients were used to verify the validity of the model. 161 groups of data were divide into hypoxic group (group H) and non-hypoxic group (group N) according to whether SpO2 was greater than 97%. For group H, the regression equation was established to describe the relationship between SFR and PFR. and calculated the value of SFR when PFR is 300. For group N, the correlation between each observation data andPFR were analyzed. Receiver operating characteristic (ROC) curve analysis was used to determine the diagnostic value of the index. Finally, a new diagnostic process was established for ARDS based on these results, and the reliability was verified with Berlin definition set as the gold standard for diagnosis and classification. Results: For group H, the diagnostic linear equation is PFR = 0.9162*SFR-21.39 ( R2=0.66 , P<0.0001 ). After calculation, when PFR is 300, SFR is 352. For group N, There is a significant negative correlation between FiO2 and PFR((R= -0.521,P<0.0001)). The AUC of using FiO2 to diagnose ARDS was 0.694 (95%CI 0.571~0.817, P ＜ 0.005). When the cutoff value of FiO2 was 39%, the sensitivity was 0.838 and the specificity was 0.545. Therefore, in this new diagnosis progress, when SpO2≤97%, if SFR≤352, ARDS may exist; when SpO2>97%, if FiO2min>39%, there may be ARDS. The sensitivity, specificity, NPV, PPV, and accuracy of the new diagnosis progress for ARDS were 91.1%, 76.7%, 89.6%, 79.6%, and 83.9%, respectively. Conclusion: There are potential value of SpO2 and FiO2 as a noninvasive diagnostic tool for ARDS by new processes in patients who are already receiving high levels of oxygen support.

Effect of intermittent hypoxic intervention on aerobic and anaerobic performance of the elite athletes

Objective: The use of hypoxic training has increased to improve the performance of endurance athletes in recent years. Due to not having the suitable conditions and environment for each athlete and team, intermittent hypoxic training has been noted. The purpose of this study is to investigate the effect of intermittent hypoxic training on aerobic and anaerobic performance of elite athletes. Materials and Methods: A total of 40 elite distance athletes were taken into our study and divided into two groups as hypoxia and normoxia. While using the intermittent intervention for the hypoxic group 5 minutes intervals for a total of 1 hour per day, 3 days per week for a-4 week period, the same normoxic training protocol was used for the normoxic group. Aerobic and anaerobic performance parameters were measured with venous blood samples of the athletes in the first three days before and after hypoxic intervention. Results: When the hypoxia and normoxia groups were evaluated before and after intermittent hypoxia, there was no statistically change in aerobic and anaerobic performance values (p>0.05). Conclusion: We observed that there was not a statistical change of intermittent hypoxic intervention for the performances of hypoxic group. However, the more dose and the duration of hypoxic training, the more amount of performance gain can be achieved.

Transcriptome Sequencing Reveals Gene Expression Differences in the Response of Malignant Melanomas Cells to Hypoxia

BackgroundMalignant melanoma (MM) is the most deadly type of skin cancer, with 5-year survival rate of less than 16%. HIF-1α overexpression is associated with poor prognosis in many cancers including MM. Hence, we characterized differentially expressed genes (DEGs) in the response of MM cells to normal and hypoxia. MethodsWe first successfully constructed cell hypoxia model and then performed RNA-seq to explore the changes of gene transcription in MM cells during hypoxia. The highest expression of the six genes was detected using qRT-PCR and western blot assays. We explored the binding sites between BIRC7 promoter and HIF-1α by dual-luciferase assay. Cellular function assays were used to observe the role of BIRC7 in the effect of hypoxia on tumor progression. ResultsWe found that compared with the transcriptome data of the control group, a total of 2601 DEGs were identified in the hypoxic group. There were 1517 genes with significantly higher expression and 1084 genes with lower expression in the hypoxic group. Among them, OSCAR, BIRC7, HBA1, SFN, GOLT1A, and BEX2 were significantly up-regulated in the hypoxic group. BIRC7 expression was most significantly up-regulated and a downstream factor of HIF-1α. We highlighted that knockdown of BIRC7 reversed the positive effects of HIF-1α on A875 and M14 cells. ConclusionsOur findings demonstrated that BIRC7 was a downstream factor of HIF-1α and reversed the effect of hypoxia on promoting tumor progression of MM cells.

Nano-Curcumin Protects Against Sodium Nitrite–Induced Lung Hypoxia Through Modulation of Mitogen-Activated Protein Kinases/c-Jun NH2-Terminal Kinase Signaling Pathway

Background and objective This study was designed to compare the efficacy of curcumin (CRN) with that of nano-curcumin (N-CRN) in the mitigation of various biochemical indices in hypoxic lung induced by sodium nitrite (SN) in rats. Methods Twenty-four adult male albino rats were divided into 4 groups. Group 1: control group received carboxy methyl cellulose; Group 2: hypoxic group injected with single dose of SN (60 mg/kg, s.c.); Group 3: SN-intoxicated rats pre-injected with CRN (100 mg/kg, i.p.); and Group 4: SN-intoxicated rats pre-injected with N-CRN (100 mg/kg, i.p.). Curcumin and N-CRN were administered intraperitoneally 2 hour prior to SN intoxication. Hemoglobin concentration, serum tumor necrosis factor-alpha (TNF-α), and caspase-3 were analyzed. Gene expression of hypoxia inducible factor-1 (HIF-1α), matrix metallo-proteinases (MMP)-2, and tissue inhibitors of metalloproteinases (TIMPs)-2, as well as the protein expression of mitogen-activated protein kinases (MAPKs) and c-Jun NH2-terminal kinase (JNK) were examined in lung tissues. Results Hemoglobin level was markedly reduced, and serum TNF-α and caspase-3 were significantly elevated post SN intoxication. The lung MMP-2 and HIF-1α mRNA were overexpressed in the hypoxic group; while TIMP-2 mRNA was downregulated. Sodium nitrite administration increased proteins’ expressions of MAPK and JNK. Pretreatment with CRN or N-CRN markedly mitigated those alterations. These results were supported by histopathological examinations of lung tissue. Conclusion Interestingly, N-CRN exhibited a pronounced protective effect via suppression of inflammatory and apoptotic biomarkers and modulation of MAPK/JNK signaling pathway.

Extracellular Superoxide Dismutase (EC-SOD) Regulates Gene Methylation and Cardiac Fibrosis During Chronic Hypoxic Stress

Chronic hypoxic stress induces epigenetic modifications mainly DNA methylation in cardiac fibroblasts, inactivating tumor suppressor genes (RASSF1A) and activating kinases (ERK1/2) leading to fibroblast proliferation and cardiac fibrosis. The Ras/ERK signaling pathway is an intracellular signal transduction critically involved in fibroblast proliferation. RASSF1A functions through its effect on downstream ERK1/2. The antioxidant enzyme, extracellular superoxide dismutase (EC-SOD), decreases oxidative stress from chronic hypoxia, but its effects on these epigenetic changes have not been fully explored. To test our hypothesis, we used an in-vitro model: wild-type C57B6 male mice (WT) and transgenic males with an extra copy of human hEC-SOD (TG). The studied animals were housed in hypoxia (10% O2) for 21 days. The right ventricular tissue was studied for cardiac fibrosis markers using RT-PCR and Western blot analyses. Primary C57BL6 mouse cardiac fibroblast tissue culture was used to study the in-vitro model, the downstream effects of RASSF-1 expression and methylation, and its relation to ERK1/2. Our findings showed a significant increase in cardiac fibrosis markers: Collagen 1, alpha smooth muscle actin (ASMA), and SNAIL, in the WT hypoxic animals as compared to the TG hypoxic group (p &lt; 0.05). The expression of DNA methylation enzymes (DNMT 1&amp;3b) was significantly increased in the WT hypoxic mice as compared to the hypoxic TG mice (p &lt; 0.001). RASSF1A expression was significantly lower and ERK1/2 was significantly higher in hypoxia WT compared to the hypoxic TG group (p &lt; 0.05). Use of SiRNA to block RASSF1A gene expression in murine cardiac fibroblast tissue culture led to increased fibroblast proliferation (p &lt; 0.05). Methylation of the RASSF1A promoter region was significantly reduced in the TG hypoxic group compared to the WT hypoxic group (0.59 vs. 0.75, respectively). Based on our findings, we can speculate that EC-SOD significantly attenuates RASSF1A gene methylation and can alleviate cardiac fibrosis induced by hypoxia.

A New ARDS Early Noninvasive Screening Protocol：Potential Value of SpO2 and FiO2 as a Diagnostic Tool

Background: A large number of recent studies have confirmed that the pulse oximetric saturation (SpO2)/fraction of inspired oxygen (FiO2) ratio (SFR) correlate well with PaO2/FiO2 ratio (PFR). However, whether SFR can replace PFR for the diagnosis and evaluate the severity of ARDS patients is unclearly. The purpose of this study is to explore potential value of SFR as a new diagnostic tool for ARDS, and establish a diagnostic process.Methods: 341 patients were included in this study, SFR and PFR values were recorded in the same time. 161 patients were used to establish the model, and 180 patients were used to verify the validity of the model. 161 groups of data were divide into hypoxic group (group H) and non-hypoxic group (group N) according to whether SpO2 was greater than 97%. For group H, the regression equation was established to describe the relationship between SFR and PFR. and calculated the value of SFR when PFR is 300. For group N, the correlation between each observation data and PFR were analyzed. Receiver operating characteristic (ROC) curve analysis was used to determine the diagnostic value of the index. Finally, a new diagnostic process was established for ARDS based on these results, and the reliability was verified with Berlin definition set as the gold standard for diagnosis and classification.Results: For group H the diagnostic linear equation is PFR = 0.9162*SFR-21.39 ( R2=0.66 , P<0.0001 ). After calculation, when PFR is 300, SFR is 352. For group N, There is a significant negative correlation between FiO2 and PFR((R= -0.521,P<0.0001)). The AUC of using FiO2 to diagnose ARDS was 0.694 (95%CI 0.571~0.817, P＜0.005). When the cutoff value of FiO2 was 39%, the sensitivity was 0.838 and the specificity was 0.545. Therefore, in this new diagnosis progress, when SpO2≤97%, if SFR≤352, ARDS may exist; when SpO2>97%, if FiO2min>39%, there may be ARDS. The sensitivity, specificity, NPV, PPV, and accuracy of the new diagnosis progress for ARDS were 91.1%, 76.7%, 89.6%, 79.6%, and 83.9%, respectively. Conclusions: There are potential value of SpO2 and FiO2 as a noninvasive diagnostic tool for ARDS.

Extracellular Superoxide Dismutase (EC-SOD) Regulates Gene Methylation and Cardiac Fibrosis During Chronic Hypoxic Stress

Background: Chronic hypoxic stress induces epigenetic modifications mainly DNA methylation in cardiac fibroblasts, inactivating tumor suppressor genes (RASSF1A), and activating kinases (ERK1/2) leading to fibroblast proliferation and cardiac fibrosis. The Ras/ERK signaling pathway is an intracellular signal transduction critically involved in fibroblast proliferation. RASSF1A functions through its effect on downstream ERK1/2. The antioxidant enzyme, extracellular superoxide dismutase (EC-SOD), decreases oxidative stress from chronic hypoxia but it’s effects on these epigenetic changes has not been fully explored. Objectives: In-vitro model: Wild type C57B6 male mice (WT) and transgenic males with an extra copy of human hEC-SOD (TG) were housed in hypoxia (10% O2) for 21 days. Right ventricular tissue was studied for cardiac fibrosis markers using RT-PCR and Western Blot analyses. in-vitro model, downstream effects of RASSF-1 expression and methylation and its relation to ERK1/2, were studied using primary C57BL6 mouse cardiac fibroblast tissue culture.Results: There were significant increases in markers of cardiac fibrosis : Collagen 1, Alpha Smooth Muscle Actin (ASMA) and SNAIL, in the WT hypoxic animals as compared to the TG hypoxic group (p< 0.05). Expression of DNA methylation enzymes (DNMT 1,2) was significantly increased in the WT hypoxic mice as compared to the hypoxic TG mice (p<0.001). RASSF1A expression was significantly lower and ERK1/2 was significantly higher in hypoxia WT compared to the hypoxic TG group (p<0.05). Use of SiRNA to block RASSF1A gene expression in murine cardiac fibroblast tissue culture led to increased fibroblast proliferation (p<0.05). Methylation of RASSF1A promoter region was significantly reduced in the TG hypoxic group compared to the WT hypoxic group (0.59 vs 0.75 respectively). Conclusions: EC-SOD significantly attenuates RASSF1A gene methylation and can alleviate cardiac fibrosis induced by hypoxia.

Myocardial Patch Formation by Three-Dimensional Culture of Bone Marrow Mesenchymal Stem Cells with 3-Hydroxybutyrate-Co-4-Hydroxybutyrate Under Hypoxia

Herein we researched the effects of a hypoxic microenvironment on bone marrow mesenchymal stem cells (BM-MSCs) on poly 3-hydroxybutyrate-co-4-hydroxybutyrate [P(3HB-co-4HB)] and present a theoretical basis for development of cell transplantation. Mouse bone marrow mesenchymal stem cells were isolated by whole bone marrow culture and surface antigens were analyzed by flow cytometry of passage 5 cells. P(3HB-co-4HB) and bone marrow mesenchymal stem cells were prepared as stem cell patches randomly divided into normoxia (control, 20% oxygen) and hypoxia (3% oxygen) groups. After 24 h, the patch was used for experiments. Cell proliferation was determined by CCK-8 assays. Adhesion, survival, and growth of cells on patches were observed by scanning electron microscopy. Expression of hypoxia-inducible factor-1α (HIF-1α) was tested by real-time quantitative PCR and western blotting. At 2 weeks after addition of cardiomyocyte differentiation inducer 5-azacytidine, cardiac troponin T (cTnT) expression was detected by immunofluorescence. After 24 h, the proliferation of the hypoxic group was considerably greater compared with the normoxic group (n = 12,P < 0 05). SEM demonstrated that the number of viable cells in the hypoxic group was higher than that in the normoxic group. Adhesion between cells and the patch was firm and cell morphology was normal in the hypoxic group. Significant upregulation of HIF-1α mRNA was observed by real-time quantitative PCR after 12 h (P < 0 05). HIF-1αprotein expression in the hypoxia group was considerably higher than that in the normoxia group. cTnT expression in the hypoxic group was more pronounced than that in the normoxic group. Our results show that a hypoxic microenvironment promotes the adhesion, survival, proliferation, and myocardial differentiation of bone marrow mesenchymal stem cells on a P(3HB-co-4HB) patch, which may be mediated by the HIF-1α; pathway.

Extracellular Superoxide Dismutase (EC-SOD) Regulates Gene Methylation and Cardiac Fibrosis During Chronic Hypoxic Stress

BackgroundChronic hypoxic stress induces epigenetic modifications in cardiac fibroblasts, such as inactivation of tumor suppressor genes (RASSF1A), and activation of kinases (ERK1/2). The effects of the antioxidant enzyme, extracellular superoxide dismutase (EC-SOD), on these epigenetic changes has not been fully explored.ObjectivesTo define the effect of EC-SOD overexpression on cardiac fibrosis induced by chronic hypoxia.MethodsWild type C57B6 male mice (WT) and transgenic males with an extra copy of human hEC-SOD (TG) were housed in hypoxia (10% O2) for 21 days. Right ventricular tissue was studied for cardiac fibrosis markers using RT-PCR and Western Blot analyses. Downstream effects were studied, for both RASSF-1 expression and methylation and its relation to ERK1/2, using in-vivo & in-vitro modelsResultsThere were significant increases in markers of cardiac fibrosis : Collagen 1, Alpha Smooth Muscle Actin (ASMA) and SNAIL, in the WT hypoxic animals as compared to the TG hypoxic group (p< 0.05). Expression of DNA methylation enzymes (DNMT 1,2) was significantly increased in the WT hypoxic mice as compared to the hypoxic TG mice (p<0.001). RASSF1A expression was significantly lower and ERK1/2 was significantly higher in hypoxia WT compared to the hypoxic TG group (p<0.05). Use of SiRNA to block RASSF1A gene expression in murine cardiac fibroblast tissue culture led to increased fibroblast proliferation (p<0.05). Methylation of RASSF1A promoter region showed a significant reduction in the TG hypoxic group compared to the WT hypoxic group (0.59 vs 0.75 respectively).ConclusionsEC-SOD significantly attenuates RASSF1A gene methylation, and plays a pivotal role cardiac fibrosis induced by hypoxia.