bims-hypoxi 2021-05-23 papers

bims-hypoxi

Biomed News

on Hypoxia and HIF1-alpha

Issue of 2021–05–23
thirty papers selected by
Ashish Kaul, University of Tsukuba

Treatment with hypoxia-mimetics protects cultured rat Schwann cells against oxidative stress-induced cell death.
The HIF-1/SNHG1/miR-199a-3p/TFAM axis explains tumor angiogenesis and metastasis under hypoxic conditions in breast cancer.
A gemcitabine-based conjugate with enhanced antitumor efficacy by suppressing HIF-1α expression under hypoxia.
Hypoxia Promotes Pancreatic Cancer Cell Dedifferentiation to Stem-Like Cell Phenotypes With High Tumorigenic Potential by the HIF-1α/Notch Signaling Pathway.
Hypoxia-dependent signaling in perioperative and critical care medicine.
Protective effects of piperine on the retina of mice with streptozotocin-induced diabetes by suppressing HIF-1/VEGFA pathway and promoting PEDF expression.
The regulation of immune checkpoints by the hypoxic tumor microenvironment.
Perinuclear mitochondrial clustering, increased ROS levels, and HIF1 are required for the activation of HSF1 by heat stress.
Hypoxia-Induced MALAT1 Promotes the Proliferation and Migration of Breast Cancer Cells by Sponging MiR-3064-5p.
The role of the HIF-1α/ALYREF/PKM2 axis in glycolysis and tumorigenesis of bladder cancer.
Phenylethanol glycosides from Herba Cistanche improve the hypoxic tumor microenvironment and enhance the effects of oxaliplatin via the HIF‑1α signaling pathway.
Interleukin-17 aggravates right ventricular remodeling via activating STAT3 under both normoxia and hypoxia.
An albumin-binding dimeric prodrug nanoparticle with long blood circulation and light-triggered drug release for chemo-photodynamic combination therapy against hypoxia-induced metastasis of lung cancer.
Cyclin-Dependent Kinase 7 Promotes Th17/Th1 Cell Differentiation in Psoriasis by Modulating Glycolytic Metabolism.
A Decade's Review of miRNA: a Center of Transcriptional Regulation of Drug-Metabolizing Enzymes and Transporters Under Hypoxia.
circAGFG1 sponges miR-28-5p to promote non-small-cell lung cancer progression through modulating HIF-1α level.
Genome-wide CRISPR/Cas9 deletion screen defines mitochondrial gene essentiality and identifies routes for tumour cell viability in hypoxia.
Links between the unfolded protein response and the DNA damage response in hypoxia: a systematic review.
MiR-448-5p/VEGFA Axis Protects Cardiomyocytes from Hypoxia Through Regulating the FAS/FAS-L Signaling Pathway.
CircJARID2 regulates hypoxia-induced injury in H9c2 cells by affecting miR-9-5p-mediated BNIP3.
Experimental Study on the Correlation between miRNA-373 and HIF-1α, MMP-9, and VEGF in the Development of HIE.
Klotho alleviates chronic intermittent hypoxia-induced genioglossus myocyte apoptosis by inhibiting endoplasmic reticulum stress.
miR-320-3p regulates the proliferation, migration and apoptosis of hypoxia-induced pulmonary arterial smooth muscle cells via KLF5 and HIF1α.
PD-L1 Regulates Inflammation in LPS-Induced Lung Epithelial Cells and Vascular Endothelial Cells by Interacting with the HIF-1α Signaling Pathway.
Effect of GLUT1 Inhibition and Autophagy Modulation on the Growth and Migration of Laryngeal Carcinoma Stem Cells Under Hypoxic and Low-Glucose Conditions.
Protein tyrosine phosphatase-PEST mediates hypoxia-induced endothelial autophagy and angiogenesis via AMPK activation.
The Protective Effects of Dexmedetomidine against Hypoxia/Reoxygenation-Induced Inflammatory Injury and Permeability in Brain Endothelial Cells Mediated by Sigma-1 Receptor.
TRPV1 sustains microglial metabolic reprogramming in Alzheimer's disease.
Worenine reverses the Warburg effect and inhibits colon cancer cell growth by negatively regulating HIF-1α.
Neuronal apoptosis can be prevented by the combined therapy with melatonin and hypothermia in a neonatal rat model of hypoxic-ischemic encephalopathy.

Glia. 2021 May 21.

Treatment with hypoxia-mimetics protects cultured rat Schwann cells against oxidative stress-induced cell death.

Brian T David, Jessica J Curtin, Jennifer L Brown, David J C Coutts, Nathan C Boles, Caitlin E Hill.

  Schwann cell (SC) grafts promote axon regeneration in the injured spinal cord, but transplant efficacy is diminished by a high death rate in the first 2-3 days postimplantation. Both hypoxic preconditioning and pharmacological induction of the cellular hypoxic response can drive cellular adaptations and improve transplant survival in a number of disease/injury models. Hypoxia-inducible factor 1 alpha (HIF-1α), a regulator of the cellular response to hypoxia, is implicated in preconditioning-associated protection. HIF-1α cellular levels are regulated by the HIF-prolyl hydroxylases (HIF-PHDs). Pharmacological inhibition of the HIF-PHDs mimics hypoxic preconditioning and provides a method to induce adaptive hypoxic responses without direct exposure to hypoxia. In this study, we show that hypoxia-mimetics, deferoxamine (DFO) and adaptaquin (AQ), enhance HIF-1α stability and HIF-1α target gene expression. Expression profiling of hypoxia-related genes demonstrates that HIF-dependent and HIF-independent expression changes occur. Analyses of transcription factor binding sites identify several candidate transcriptional co-regulators that vary in SCs along with HIF-1α. Using an in vitro model system, we show that hypoxia-mimetics are potent blockers of oxidative stress-induced death in SCs. In contrast, traditional hypoxic preconditioning was not protective. The robust protection induced by pharmacological preconditioning, particularly with DFO, indicates that pharmacological induction of hypoxic adaptations could be useful for promoting transplanted SC survival. These agents may also be more broadly useful for protecting SCs, as oxidative stress is a major pathway that drives cellular damage in the context of neurological injury and disease, including demyelinating diseases and peripheral neuropathies.

Keywords:  H2O2; adaptaquin; cell death; cell survival; deferoxamine; hypoxia adaptations; hypoxia inducible factor (HIF); preconditioning; prolyl hydroxylase inhibition; reporter assay

DOI:  https://doi.org/10.1002/glia.24019
Biofactors. 2021 May 18.

The HIF-1/SNHG1/miR-199a-3p/TFAM axis explains tumor angiogenesis and metastasis under hypoxic conditions in breast cancer.

Yonggang Zuo, Changping Qu, Yanyan Tian, Yuqing Wen, Shuguan Xia, Mingde Ma.

  Activation of hypoxia-inducible factors (HIFs) as a result of intratumoral hypoxia modulates a cascade of molecular pathways thus leading to angiogenesis and metastasis in many solid tumors, including breast cancer (BC). In our paper, we report a regulatory axis of HIF-1, SNHG1, miR-199a-3p, and mitochondrial transcription factor A (TFAM) involved in tumor angiogenesis and metastasis under hypoxic conditions in BC. The expression of SNHG1 was determined in human BC cells cultured in hypoxia (1% O2 , 24 h) and normoxia (20% O2 , 24 h). Cultured MDA-MB-231 cells were assayed for the proliferation, migration, invasion, angiogenesis in vitro by using EdU staining, transwell chamber assays, Matrigel-based angiogenesis assays, tumorigenesis, and lung metastasis in vivo by using an orthotopic-transplant model of human BC. Dual-luciferase reporter assay, chromatin immunoprecipitation quantitative polymerase chain reaction assay, fluorescence in situ hybridization assay, RNA-binding protein immunoprecipitation assay, and RNA pull-down were performed to test interaction between HIF-1 and SNHG1, SNHG1 and miR-199a-3p, miR-199a-3p and TFAM. SNHG1 was increased under hypoxic conditions at a HIF-1-dependent manner. SNHG1 knockdown tempered MDA-MB-231 cell proliferation, migration, invasion, angiogenesis, in vitro, tumorigenesis, and lung metastasis in vitro. SNHG1 was co-expressed with miR-199a-3p and regulated the TFAM, a target gene of miR-199a-3p. SNHG1 increased the TFAM by binding with miR-199a-3p, thus promoting BC development and metastasis. These results support a regulatory axis consisting of HIF-1, SNHG1, miR-199a-3p, and TFAM during BC development and metastasis under hypoxic conditions, providing an opportunity to develop targeted therapeutics for BC.

Keywords:  SNHG1; TFAM; breast cancer; hypoxia-inducible factor-1; metastasis; miR-199a-3p

DOI:  https://doi.org/10.1002/biof.1702
Bioorg Med Chem. 2021 May 11. pii: S0968-0896(21)00222-4. [Epub ahead of print]41 116214

A gemcitabine-based conjugate with enhanced antitumor efficacy by suppressing HIF-1α expression under hypoxia.

Zichen Xu, Bin Zhang, Zhixin Liao, Shaohua Gou.

  Hypoxia is one of the unique features of tumor physiology. Hypoxia inducible factor (HIF-1α), as a major transcription factor in response to hypoxia, has been considered as a promising tumor-specific target for anticancer therapy. The formation of a hypoxic microenvironment in tumors can decrease the curative effect of cytotoxic chemotherapeutic drugs. To promote the antitumor efficacy of chemotherapy by suppressing hypoxia, we designed and prepared a novel gemcitabine-based drug conjugate (GEM-5) containing a HIF-1α inhibitor (YC-1). As expected, GEM-5 showed excellent antiproliferative activity (IC50 = 0.03 μΜ under hypoxia) and remarkably induced the apoptosis of A2780 cells in vitro. Additionally, western blot analysis demonstrated that GEM-5 significantly down-regulated the expression of HIF-1α and up-regulated the expression of tumor suppressor p53. More importantly, GEM-5 effectively inhibited tumor growth in the A2780 xenograft mouse model and significantly ameliorated tumor hypoxia in vivo. This novel, simple, and effective strategy for overcoming tumor hypoxia and enhancing the antitumor effect of chemotherapeutic drugs has great potential in cancer therapy.

Keywords:  Ameliorate tumor hypoxia; Cancer therapy; Gemcitabine; HIF-1α; Hypoxia

DOI:  https://doi.org/10.1016/j.bmc.2021.116214
Pancreas. 2021 May 19.

Hypoxia Promotes Pancreatic Cancer Cell Dedifferentiation to Stem-Like Cell Phenotypes With High Tumorigenic Potential by the HIF-1α/Notch Signaling Pathway.

Rui Mu, Yong-Kang Zou, Kui Tu, Dian-Bei Wang, Dan Tang, Zhou Yu, Lijin Zhao.

OBJECTIVES: This study aimed to investigate the effect and mechanism of hypoxia on pancreatic cancer (PC) cell dedifferentiation and tumorigenic potential.
METHODS: Inhibition of hypoxia-inducible factor 1α (HIF-1α) and overexpression of Notch1 in PC HS766T cell lines were by lentiviral transfection. The expression of stem cell-specific markers C-X-C motif chemokine receptor 4, CD44, and Nestin was detected by immunofluorescence and Western blot assays. Cell invasion capacity was examined by Transwell assay. Tumorigenic potential was measured in an in situ tumor transplantation experiment. The expression of HIF-1α, Notch signals, and apoptosis signals was examined by Western blot assay.
RESULTS: Hypoxia promoted PC cells to dedifferentiate into stem-like cells by upregulating HIF-1α and activating Notch signals. Silencing of HIF-1α significantly repressed cell dedifferentiation and invasion, whereas overexpression of Notch1 reversed the effect of HIF-1α repression. In situ tumor transplantation experiment further confirmed that hypoxia promoted tumorigenic ability through upregulating HIF-1α. Moreover, the expression of HIF-1α and Notch1 was significantly increased in human PC tissues, and high expression of HIF-1α was correlated with poor survival rate.
CONCLUSIONS: Hypoxia promoted PC cell dedifferentiation to stem-like cell phenotypes with high tumorigenic potential by activating HIF-1α/Notch signaling pathway, indicating a novel role in regulating PC progression.

DOI: https://doi.org/10.1097/MPA.0000000000001828
J Anesth. 2021 May 18.

Hypoxia-dependent signaling in perioperative and critical care medicine.

Kiichi Hirota.

  A critical goal of patient management for anesthesiologists and intensivists is to maintain oxygen homeostasis in patients admitted to operation theaters and intensive care units. For this purpose, it is imperative to understand the strategies of the body against oxygen imbalance-especially oxygen deficiency (hypoxia). Adaptation to hypoxia and maintenance of oxygen homeostasis involve a wide range of responses that occur at different organizational levels in the body. These responses are greatly influenced by perioperative patient management including factors such as perioperative drugs. Herein, the influence of perioperative patient management on the body's response to oxygen imbalance was reviewed with a special emphasis on hypoxia-inducible factors (HIFs), transcription factors whose activity are regulated by the perturbation of oxygen metabolism. The 2019 Nobel Prize in Physiology or Medicine was awarded to three researchers who made outstanding achievements in this field. While previous studies have reported the effect of perioperatively used drugs on hypoxia-induced gene expression mediated by HIFs, this review focused on effects of subacute or chronic hypoxia changes in gene expression that are mediated by the transcriptional regulator HIFs. The clinical implications and perspectives of these findings also will be discussed. Understanding the basic biology of the transcription factor HIF can be informative for us since anesthesiologists manage patients during the perioperative period facing the imbalances the oxygen metabolism in organ and tissue. The clinical implications of hypoxia-dependent signaling in critical illness, including Coronavirus disease (COVID-19), in which disturbances in oxygen metabolism play a major role in its pathogenesis will also be discussed.

Keywords:  Anesthesia; Hypoxia; Hypoxia-inducible factor; Oxygen metabolism; Perioperative care

DOI:  https://doi.org/10.1007/s00540-021-02940-w
Int J Ophthalmol. 2021 ;14(5): 656-665

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

Pu Zhang, Yan-Dan Zhou, Yao Tan, Ling Gao.

   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.

Keywords:  diabetes; diabetic retinopathy; hypoxia-inducible factor-1α/vascular endothelial growth factor A pathway; mice; pigment epithelium-derived factor; piperine

DOI:  https://doi.org/10.18240/ijo.2021.05.04
PeerJ. 2021 ;9 e11306

The regulation of immune checkpoints by the hypoxic tumor microenvironment.

Min Hu, Yongfu Li, Yuting Lu, Miao Wang, Yingrui Li, Chaoying Wang, Qin Li, Hong Zhao.

  The tumor microenvironment (TME) influences the occurrence and progression of tumors, and hypoxia is an important characteristic of the TME. The expression of programmed death 1 (PD1)/programmed death-ligand 1 (PDL1), cytotoxic T-lymphocyte-associated antigen 4 (CTLA4), and other immune checkpoints in hypoxic malignant tumors is often significantly increased, and is associated with poor prognosis. The application of immune checkpoint inhibitors (ICIs) for treating lung cancer, urothelial carcinoma, and gynecological tumors has achieved encouraging efficacy; however, the rate of efficacy of ICI single-drug treatment is only about 20%. In the present review, we discuss the possible mechanisms by which the hypoxic TME regulates immune checkpoints. By activating hypoxia-inducible factor-1α (HIF-1α), regulating the adenosine (Ado)-A2aR pathway, regulating the glycolytic pathway, and driving epithelial-mesenchymal transition (EMT) and other biological pathways, hypoxia regulates the expression levels of CTLA4, PD1, PDL1, CD47, lymphocyte activation gene 3 (LAG3), T-cell immunoglobulin and mucin domain 3 (TIM3), and other immune checkpoints, which interfere with the immune effector cell anti-tumor response and provide convenient conditions for tumors to escape immune surveillance. The combination of HIF-1α inhibitors, Ado-inhibiting tumor immune microenvironment regulatory drugs, and other drugs with ICIs has good efficacy in both preclinical studies and phase I-II clinical studies. Exploring the effects of TME hypoxia on the expression of immune checkpoints and the function of infiltrating immune cells has greatly clarified the relationship between the hypoxic TME and immune escape, which is of great significance for the development of new drugs and the search for predictive markers of the efficacy of immunotherapy for treating malignant tumors. In the future, combination therapy with hypoxia pathway inhibitors and ICIs may be an effective anti-tumor treatment strategy.

Keywords:  Drug treatment; Hypoxia; Immune checkpoints; Immune escape; Tumor microenvironment

DOI:  https://doi.org/10.7717/peerj.11306
J Cell Sci. 2020 Jan 01. pii: jcs.245589. [Epub ahead of print]

Perinuclear mitochondrial clustering, increased ROS levels, and HIF1 are required for the activation of HSF1 by heat stress.

Saloni Agarwal, Subramaniam Ganesh.

  Heat shock response (HSR) is a conserved cellular defensive response against stresses such as temperature, oxidative stress, and heavy metals. A significant group of players in HSR is the set of molecular chaperones, known as heat shock proteins (HSPs) that assist in the refolding of unfolded proteins and prevent the accumulation of damaged proteins. HSP genes are activated by the HSF1 transcription factor-a master regulator of the HSR pathway. A variety of stressors activates HSF1, but the key molecular players and the process that directly contribute to the HSF1 activation remains unclear. In this study, we show that heat shock induces perinuclear clustering of mitochondria in mammalian cells, and this clustering is essential for the activation of HSR. We also show that this perinuclear clustering of mitochondria results in the increased levels of ROS in the nucleus, leading to the activation of hypoxia-inducible factor-1α (HIF-1α). Finally, we provide evidence to suggest that HIF-1α is one of the critical regulators of HSF1 and that HIF-1α is essential for the activation of HSR during a heat shock.

Keywords:  Chaperones; Hypoxia response; Mitochondrial transport; Oxidative stress; Stress response; Transcriptional regulation

DOI:  https://doi.org/10.1242/jcs.245589
Front Oncol. 2021 ;11 658151

Hypoxia-Induced MALAT1 Promotes the Proliferation and Migration of Breast Cancer Cells by Sponging MiR-3064-5p.

Chung-Hsien Shih, Li-Ling Chuang, Mong-Hsun Tsai, Li-Han Chen, Eric Y Chuang, Tzu-Pin Lu, Liang-Chuan Lai.

  Hypoxia, a common process during tumor growth, can lead to tumor aggressiveness and is tightly associated with poor prognosis. Long noncoding RNAs (lncRNAs) are long ribonucleotides (>200 bases) with limited ability to translate proteins, and are known to affect many aspects of cellular function. One of their regulatory mechanisms is to function as a sponge for microRNA (miRNA) to modulate its biological functions. Previously, MALAT1 was identified as a hypoxia-induced lncRNA. However, the regulatory mechanism and functions of MALAT1 in breast cancer are still unclear. Therefore, we explored whether MALAT1 can regulate the functions of breast cancer cells through miRNAs. Our results showed the expression levels of MALAT1 were significantly up-regulated under hypoxia and regulated by HIF-1α and HIF-2α. Next, in contrast to previous reports, nuclear and cytoplasmic fractionation assays and fluorescence in situ hybridization indicated that MALAT1 was mainly located in the cytoplasm. Therefore, the labeling of MALAT1 as a nuclear marker should be done with the caveat. Furthermore, expression levels of miRNAs and RNA immunoprecipitation using antibody against AGO2 showed that MALAT1 functioned as a sponge of miRNA miR-3064-5p. Lastly, functional assays revealed that MALAT1 could promote cellular migration and proliferation of breast cancer cells. Our findings provide evidence that hypoxia-responsive long non-coding MALAT1 could be transcriptionally activated by HIF-1α and HIF-2α, act as a miRNA sponge of miR-3064-5p, and promote tumor growth and migration in breast cancer cells. These data suggest that MALAT1 may be a candidate for therapeutic targeting of breast cancer progression.

Keywords:  MALAT1; breast cancer; hypoxia; hypoxia inducible factor-1α; long non-coding RNA; miR-3064-5p; microRNA

DOI:  https://doi.org/10.3389/fonc.2021.658151
Cancer Commun (Lond). 2021 May 15.

The role of the HIF-1α/ALYREF/PKM2 axis in glycolysis and tumorigenesis of bladder cancer.

Jing-Zi Wang, Wei Zhu, Jie Han, Xiao Yang, Rui Zhou, Hong-Cheng Lu, Hao Yu, Wen-Bo Yuan, Peng-Chao Li, Jun Tao, Qiang Lu, Ji-Fu Wei, Haiwei Yang.

   BACKGROUND: As a rate-limiting enzyme of glycolysis, pyruvate kinase muscle isozyme M2 (PKM2) participates in tumor metabolism and growth. The regulatory network of PKM2 in cancer is complex and has not been fully studied in bladder cancer. The 5-methylcytidine (m5C) modification in PKM2 mRNA might participate in the pathogenesis of bladder cancer and need to be further clarified. This study aimed to investigate the biological function and regulatory mechanism of PKM2 in bladder cancer.
METHODS: The expression of PKM2 and Aly/REF export factor (ALYREF) was measured by Western blotting, qRT-PCR, and immunohistochemistry. The bioprocesses of bladder cancer cells were demonstrated by a series of experiments in vitro and in vivo. RNA immunoprecipitation, RNA-sequencing, and dual-luciferase reporter assays were conducted to explore the potential regulatory mechanisms of PKM2 in bladder cancer.
RESULTS: In bladder cancer, we first demonstrated that ALYREF stabilized PKM2 mRNA and bound to its m5C sites in 3'-untranslated regions. Overexpression of ALYREF promoted bladder cancer cell proliferation by PKM2-mediated glycolysis. Furthermore, high expression of PKM2 and ALYREF predicted poor survival in bladder cancer patients. Finally, we found that hypoxia-inducible factor-1alpha (HIF-1α) indirectly up-regulated the expression of PKM2 by activating ALYREF in addition to activating its transcription directly.
CONCLUSIONS: The m5C modification in PKM2 mRNA in the HIF-1α/ALYREF/PKM2 axis may promote the glucose metabolism of bladder cancer, providing a new promising therapeutic target for bladder cancer.

Keywords:  5-methylcytidine modification; ALYREF; HIF-1α; PKM2; bladder cancer; glycolysis

DOI:  https://doi.org/10.1002/cac2.12158
Mol Med Rep. 2021 Jul;pii: 517. [Epub ahead of print]24(1):

Phenylethanol glycosides from Herba Cistanche improve the hypoxic tumor microenvironment and enhance the effects of oxaliplatin via the HIF‑1α signaling pathway.

Limei Wen, Junping Hu, Jiawei Zhang, Jianhua Yang.

  Liver cancer is one of the most common types of malignant tumor, and is characterized by high malignancy, rapid progression, high morbidity and mortality. Oxaliplatin (OXA) has been reported to have marked efficiency against advanced liver cancer with tolerable toxicity. In solid tumors, the hypoxic microenvironment promotes epithelial‑mesenchymal transition (EMT), which can also induce drug resistance of liver cancer to platinum drugs. Herba Cistanche (Cistanche tubulosa) has been frequently used in traditional Chinese medicine and the phenylethanol glycosides from Herba Cistanche (CPhGs) are the major active components. The present study aimed to investigate the effects of CPhGs on viability, apoptosis, migration and invasion of liver cancer cells. HepG2 liver cancer cells were divided into the control, DMSO, CoCl2, OXA, OXA + CoCl2 and CPhGs + OXA + CoCl2 groups. Subsequently, reverse transcription‑quantitative PCR and western blot analysis were performed to determine the expression levels of hypoxia‑inducible factor 1α (HIF‑1α), lysyl oxidase‑like 2 (LOXL2) and EMT‑related genes and proteins (i.e., E‑cadherin and Twist), in order to investigate the effects of CPhGs on liver cancer. The results demonstrated that CPhGs could enhance the effects of OXA on liver cancer, and inhibit the migration, invasion and apoptotic rate of liver cancer cells. Additionally, CPhGs treatment effectively induced downregulation of HIF‑1α, LOXL2 and Twist, and upregulation of E‑cadherin. The present findings indicated that CPhGs triggered a significant increase in sensitivity to OXA and suppression of hypoxia‑induced EMT in liver cancer by inhibiting the HIF‑1α signaling pathway. Therefore, CPhGs may be considered an effective platinum drug sensitizer, which could improve chemotherapeutic efficacy in patients with liver cancer.

Keywords:  HIF‑1α signaling pathway; epithelial‑mesenchymal transition; hypoxia; liver cancer; phenylethanol glycosides from Herba Cistanche

DOI:  https://doi.org/10.3892/mmr.2021.12156
BMC Cardiovasc Disord. 2021 May 21. 21(1): 249

Interleukin-17 aggravates right ventricular remodeling via activating STAT3 under both normoxia and hypoxia.

Jing Huang, Wei Zhang, Cai-Lian Zhang, Lei Wang.

   OBJECTIVE: Proinflammatory cytokine interleukin 17 (IL-17) is involved in ventricular remodeling, mainly of the left ventricle. This study was designed to explore the role of IL-17 played in the pathogenesis of right ventricular hypertrophy (RVH), aiming to provide a novel treatment target or diagnostic biomarker options for improving the care of RVH patients.
METHODS: C57BL/6 mice were maintained in 10% O2 chamber or room air for four weeks. Right ventricular hypertrophy index (RVHI), RV/body weight ratio, pulmonary arteriolar remodeling determined by percent media thickness (%MT), and the cardiomyocyte diameter of RV were evaluated. Mice were treated with exogenous recombinant mouse IL-17 (rmIL-17, 1 μg per dose twice a week) for four weeks. H9c2 cardiomyocytes were cultured and treated with IL-17 (10 ng/mL) and STAT3 inhibitor (10 ng/mL) either under normoxia (21% O2, 5% CO2, 74% N2) or under hypoxia (3% O2, 5% CO2, 92% N2). Cardiomyocyte viability was assessed by Cell counting kit 8 (CCK-8) assay. The mRNA level was detected by RT-PCR, where as the protein expression was measured by Western blot, immunohistochemistry, and immunofluorescent analyses.
RESULTS: In vivo experiments showed that IL-17 did not affect the pulmonary artery under normoxia, after treatment with rmIL-17, %MT was not changed, while RVHI and the RV/body weight ratio were increased, indicating that IL-17 directly induced right ventricular hypertrophy. In a time-course study, the mice were exposed to hypoxia for 0, 1, 2, 3, 4 weeks, respectively. We found that the expression of IL-17 was gradually upregulated in RV tissue in a time-dependent manner after one week of hypoxia exposure, especially at the third and fourth week. Cardiomyocyte hypertrophy and apoptosis were observed after the exposure of the mice to hypoxia for four weeks, rmIL-17 further aggravated the hypoxia-induced cardiomyocyte hypertrophy and apoptosis. The expression of p-STAT3 in the IL-17-deficient mice was lower than in the wild-type mice. In vitro, IL-17 inhibited cardiomyocyte viability and induced cardiomyocyte apoptosis via STAT3 under both normoxic and hypoxic conditions.
CONCLUSIONS: These findings support a role for IL-17 as a mediator in the pathogenesis RVH, which might be considered as a potential novel anti-inflammation therapeutic strategy or diagnostic biomarker for RVH.

Keywords:  IL-17; Right ventricular hypertrophy; STAT3; cardiomyocyte apoptosis

DOI:  https://doi.org/10.1186/s12872-021-02069-4
Biomater Sci. 2021 May 18. 9(10): 3718-3736

An albumin-binding dimeric prodrug nanoparticle with long blood circulation and light-triggered drug release for chemo-photodynamic combination therapy against hypoxia-induced metastasis of lung cancer.

Renjie Luo, Zhongtao Zhang, Lingfei Han, Zhen Xue, Kexin Zhang, Fulei Liu, Feng Feng, Jingwei Xue, Wenyuan Liu, Wei Qu.

Photodynamic therapy (PDT) has been widely used in cancer therapy, but its therapeutic effect is reduced by the aggravating hypoxic microenvironment via upregulating hypoxia-associated proteins and promoting tumor metastasis. To mitigate these issues, we designed an albumin-binding and light-triggered core-shell dimeric prodrug nanoparticle to inhibit hypoxia-induced tumor metastasis and enhance the PDT efficacy. The prodrug nanoparticles, Ce6&DHA-S-DHA@CMN NPs (CDC NPs), were prepared using a single thioether-linked dihydroartemisinin (DHA) dimer co-encapsulated with Chlorin e6 (Ce6) and stabilized by albumin-capturing maleimide- and hypoxia-sensitive 2-nitroimidazole-modified carboxymethyl chitosan (CMCTS-MAL&NI, CMN for short). Upon laser irradiation, Ce6 could generate reactive oxygen species (ROS), which not only exerted the effect of the PDT but also broke the ROS-sensitive single thioether bridge in the dimeric prodrug DHA-S-DHA, thus accelerating the disassembly of the nanoparticles. DHA-S-DHA served as both an ROS-responsive carrier for Ce6 and a chemotherapeutic drug, synergizing with PDT and inhibiting tumor metastasis by downregulating hypoxia-inducible factor-1α (HIF-1α)/vascular endothelial growth factor (VEGF). Polyethylene glycol (PEG) modification has been widely used to stabilize hydrophobic prodrug nanoparticles and prolong the circulation time, but the PEGylated nanoparticles always suffer from accelerated blood clearance (ABC), a phenomenon which restricts their application severely. In this study, PEG was replaced by an amphipathic micelle, CMN, which could specifically capture albumin in the blood, conferring the nanoparticles long circulation and no ABC phenomenon. Under the aggravating hypoxic condition during PDT, the conversion of 2-nitroimidazole groups to 2-aminoimidazole groups in CMN could destabilize the structure of the shell and accelerate drug release. Results showed that the novel CDC NPs exhibited unique advantages in chemo-photodynamic combination therapy, such as long systemic circulation, high tumor accumulation, light-triggered drug release, HIF-1α/VEGF downregulation, and anti-metastasis efficacy, which provided a new route to overcome the ABC phenomenon of the PEGylated prodrug nanoparticles and reverse the hypoxia-induced metastasis simultaneously.

DOI: https://doi.org/10.1039/d1bm00284h
J Invest Dermatol. 2021 May 15. pii: S0022-202X(21)01232-X. [Epub ahead of print]

Cyclin-Dependent Kinase 7 Promotes Th17/Th1 Cell Differentiation in Psoriasis by Modulating Glycolytic Metabolism.

Yiting Lin, Ke Xue, Qingyang Li, Zhenhua Liu, Zhenlai Zhu, Jiaoling Chen, Erle Dang, Lei Wang, Weigang Zhang, Gang Wang, Bing Li.

Excessive activation of CD4+ T cells and Th17/Th1 cell differentiation are critical events in psoriasis pathogenesis, but the associated molecular mechanism is still unclear. Here, using quantitative proteomics analysis we found that CDK7 expression was markedly increased in CD4+ T cells from psoriasis patients compared with healthy controls, and was positively correlated with psoriasis severity. Meanwhile, genetic or pharmacological inhibition of CDK7 ameliorated the severity of psoriasis in imiquimod-induced psoriasis-like mouse model and suppressed CD4+ T cell activation as well as Th17/Th1 cell differentiation in vivo and in vitro. Furthermore, the CDK7 inhibitor also reduced the enhanced glycolysis of CD4+ T cells from psoriasis patients. Proinflammatory cytokine IL-23 induced increased CDK7 expression in CD4+ T cells, and activated AKT/mTOR/HIF-1α signaling pathway, enhancing glycolytic metabolism. Correspondingly, CDK7 inhibition significantly impaired IL-23-induced glycolysis via the AKT/mTOR/HIF-1α pathway. In summary, our study demonstrates that CDK7 promotes CD4+ T cell activation and Th17/Th1 cell differentiation by regulating glycolysis, thus contributes to the pathogenesis of psoriasis. Targeting CDK7 might be a promising immunosuppressive strategy to control skin inflammation mediated by IL-23.

DOI: https://doi.org/10.1016/j.jid.2021.04.018
Curr Drug Metab. 2021 May 13.

A Decade's Review of miRNA: a Center of Transcriptional Regulation of Drug-Metabolizing Enzymes and Transporters Under Hypoxia.

Yabin Duan, Junbo Zhu, Jianxin Yang, Wenqi Gu, Xue Bai, Guiqin Liu, Li Xiangyang.

   BACKGROUND: Hypoxia has a negative effect on the cardiovascular system, nervous system, and metabolism, which contributes to potential changes in drug absorption, distribution, metabolism, and excretion (ADME). However, hypoxia can also alter the expression of microRNA (miRNA), thereby regulating drug-metabolizing enzymes, transporters, and ADME genes, such as hypoxia-inducible factor, inflammatory cytokine, nuclear receptor, etc. Therefore, it is crucial to study the role of miRNA in the regulation of drug-metabolizing enzymes and transporters under hypoxia.
METHODS: A systematic review of published studies was carried out to investigate the role of miRNA in the regulation of drug-metabolizing enzymes and transporters under hypoxia. Data and information on expression changes in miRNA, drug-metabolizing enzymes, and transporters under hypoxia were analyzed and summarized.
RESULTS: Hypoxia can up- or down-regulate the expression of miRNA. The effect of hypoxia on Cytochrome P450 (CYP450) is still a subject of debate. The widespread belief is that hypoxia decreased the activity and expression of CYP1A1, CYP1A2, CYP2E1, and CYP3A1 and increased those of CYP3A6 and CYP2D1 in rats. Hypoxia increased the expression of a multidrug resistance-associated protein, breast cancer resistance protein, peptide transporter, organic cation transporter, and organic anion transporter. miRNA negatively regulated the expression of drug-metabolizing enzymes and transporters.
CONCLUSION: The findings of this review indicated that miRNA plays a key role in the expression changes of drug-metabolizing enzymes and transporters under hypoxia.

Keywords:  Cytochrome P450; Drug transporters; Drug-metabolizing enzymes; Hypoxia; Mechanism.; miRNA

DOI:  https://doi.org/10.2174/1389200222666210514011313
Open Med (Wars). 2021 ;16(1): 703-717

circAGFG1 sponges miR-28-5p to promote non-small-cell lung cancer progression through modulating HIF-1α level.

Xiaoan Ma, Cuijie Wang, Juan Chen, Dan Wei, Fei Yu, Juan Sun.

  Circular RNAs (circRNAs) have gained much attention for their crucial regulatory roles in human diseases and cancers. However, the role and the mechanism of circRNA ArfGAP with FG repeats 1 (circAGFG1) in non-small-cell lung cancer (NSCLC) are still largely unknown. circAGFG1 was highly expressed in NSCLC, and high expression of circAGFG1 was closely related to the low survival rate of NSCLC patients. circAGFG1 knockdown inhibited the proliferation, migration, and invasion and promoted the apoptosis of NSCLC cells. circAGFG1 bound to miR-28-5p in NSCLC cells, and circAGFG1 promoted NSCLC progression partly through sponging miR-28-5p in vitro. HIF-1α was a target of miR-28-5p, and miR-28-5p overexpression-mediated influences in NSCLC cells were partly overturned by the addition of HIF-1α overexpression plasmid. circAGFG1/miR-28-5p/HIF-1α axis regulated cellular glycolytic metabolism in NSCLC cells. circAGFG1 silencing restrained the xenograft tumor growth in vivo. circAGFG1 promoted the proliferation, migration, and invasion and suppressed the apoptosis of NSCLC cells through accelerating the glycolysis via miR-28-5p/HIF-1α axis.

Keywords:  HIF-1α; NSCLC; circAGFG1; glycolysis; miR-28-5p

DOI:  https://doi.org/10.1515/med-2021-0269
Commun Biol. 2021 May 21. 4(1): 615

Genome-wide CRISPR/Cas9 deletion screen defines mitochondrial gene essentiality and identifies routes for tumour cell viability in hypoxia.

Luke W Thomas, Cinzia Esposito, Rachel E Morgan, Stacey Price, Jamie Young, Steven P Williams, Lucas A Maddalena, Ultan McDermott, Margaret Ashcroft.

Mitochondria are typically essential for the viability of eukaryotic cells, and utilize oxygen and nutrients (e.g. glucose) to perform key metabolic functions that maintain energetic homeostasis and support proliferation. Here we provide a comprehensive functional annotation of mitochondrial genes that are essential for the viability of a large panel (625) of tumour cell lines. We perform genome-wide CRISPR/Cas9 deletion screening in normoxia-glucose, hypoxia-glucose and normoxia-galactose conditions, and identify both unique and overlapping genes whose loss influences tumour cell viability under these different metabolic conditions. We discover that loss of certain oxidative phosphorylation (OXPHOS) genes (e.g. SDHC) improves tumour cell growth in hypoxia-glucose, but reduces growth in normoxia, indicating a metabolic switch in OXPHOS gene function. Moreover, compared to normoxia-glucose, loss of genes involved in energy-consuming processes that are energetically demanding, such as translation and actin polymerization, improve cell viability under both hypoxia-glucose and normoxia-galactose. Collectively, our study defines mitochondrial gene essentiality in tumour cells, highlighting that essentiality is dependent on the metabolic environment, and identifies routes for regulating tumour cell viability in hypoxia.

DOI: https://doi.org/10.1038/s42003-021-02098-x
Biochem Soc Trans. 2021 May 18. pii: BST20200861. [Epub ahead of print]

Links between the unfolded protein response and the DNA damage response in hypoxia: a systematic review.

Hannah Bolland, Tiffany S Ma, Syafiq Ramlee, Kristijan Ramadan, Ester M Hammond.

  Hypoxia is a feature of most solid tumours and predicts for poor prognosis. In radiobiological hypoxia (<0.1% O2) cells become up to three times more resistant to radiation. The biological response to radiobiological hypoxia is one of few physiologically relevant stresses that activates both the unfolded protein and DNA damage responses (UPR and DDR). Links between these pathways have been identified in studies carried out in normoxia. Based in part on these previous studies and recent work from our laboratory, we hypothesised that the biological response to hypoxia likely includes overlap between the DDR and UPR. While inhibition of the DDR is a recognised strategy for improving radiation response, the possibility of achieving this through targeting the UPR has not been realised. We carried out a systematic review to identify links between the DDR and UPR, in human cell lines exposed to <2% O2. Following PRISMA guidance, literature from January 2010 to October 2020 were retrieved via Ovid MEDLINE and evaluated. A total of 202 studies were included. LAMP3, ULK1, TRIB3, CHOP, NOXA, NORAD, SIAH1/2, DYRK2, HIPK2, CREB, NUPR1, JMJD2B, NRF2, GSK-3B, GADD45a, GADD45b, STAU1, C-SRC, HK2, CAV1, CypB, CLU, IGFBP-3 and SP1 were highlighted as potential links between the hypoxic DDR and UPR. Overall, we identified very few studies which demonstrate a molecular link between the DDR and UPR in hypoxia, however, it is clear that many of the molecules highlighted warrant further investigation under radiobiological hypoxia as these may include novel therapeutic targets to improve radiotherapy response.

Keywords:  DDR; ER stress; UPR; hypoxia; radiation; replication stress

DOI:  https://doi.org/10.1042/BST20200861
Int Heart J. 2021 May 15.

MiR-448-5p/VEGFA Axis Protects Cardiomyocytes from Hypoxia Through Regulating the FAS/FAS-L Signaling Pathway.

Hanqing Tang, Shitian Zhang, Cenhan Huang, Keming Li, Qiuhua Zhao, Xiaohua Li.

  Bioinformatics analysis showed that miR-448-5p expression in the myocardial tissue of rats with myocardial infarction significantly increased, suggesting that it may participate in myocardial cell apoptosis in myocardial infarction. This study aimed to explore the protective effects of miR-448-5p on hypoxic myocardial cells.H9C2 cells were cultured and subjected to anoxia for 2, 4, and 8 hours to establish a hypoxia model. MiR-448-5p mimic and inhibitor were transfected into the cells; then, a dual-luciferase experiment was conducted to verify the targeting relationship between miR-448-5p and VEGFA. Cell viability and apoptosis was detected by cell counting kit-8 and ﬂow cytometry, respectively. The expressions of apoptosis-related proteins, miR-448-5p, FAS, and FAS-L were measured using western blotting and quantitative reverse transcription-polymerase chain reaction (qRT-PCR).Hypoxia-reduced H9C2 cell viability and promoted apoptosis. MiR-448-5p expression was increased after H9C2 cell hypoxia. MiR-448-5p mimic significantly inhibited the viability and promoted the apoptosis of hypoxia-induced model cells. Hypoxia promoted the expression of apoptosis-related protein B-cell lymphoma-2 (Bcl-2) and inhibited the expressions of Bcl-2-associated x protein (Bax), cleaved caspase-3, and caspase-3, whereas the effect of inhibitor on hypoxia-reduced H9C2 cell and apoptotic protein expression were opposite to miR-448-5p mimic. MiR-448-5p targeted VEGFA and regulated its expression. Silenced VEGFA expression significantly inhibited inhibitor effect on increasing cell viability and promoted apoptosis. In addition, miR-448-5p mimic inhibited the effect of hypoxia on promoting the expressions of FAS and FAS-L of H9C2 cells. Inhibitors had the opposite effect on cell hypoxia model.The miR-448-5p/VEGFA axis could protect cardiomyocytes from hypoxia through inhibiting the FAS/FAS-L signaling pathway.

Keywords:  Cell viability; Hypdoxia injury

DOI:  https://doi.org/10.1536/ihj.20-600
J Cardiovasc Pharmacol. 2021 Apr 17.

CircJARID2 regulates hypoxia-induced injury in H9c2 cells by affecting miR-9-5p-mediated BNIP3.

Xinyong Cai, Bin Li, Yunxia Wang, Hongmin Zhu, Ping Zhang, Panpan Jiang, Xu Yang, Lang Hong, Liang Shao.

ABSTRACT: Myocardial infarction (MI) is a common cardiovascular disease and many circular RNAs (circRNAs) have been found to participate in the pathological process. This study was to research circRNA jumonji and AT-rich interaction domain containing 2 (circJARID2) in MI. MI cell model was established by hypoxia treatment in H9c2 cells. CircJARID2 and microRNA-9-5p (miR-9-5p) levels were examined using real-time polymerase chain reaction (qRT-PCR). Cell viability detection was performed by Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (Edu) assays. Cell apoptosis was evaluated by flow cytometry and caspase-3 activity assay. Apoptotic markers and B-cell lymphoma-2 (Bcl-2) interacting protein 3 (BNIP3) were quantified by western blot. Inflammatory cytokines were determined via Enzyme-linked immunosorbent assay (ELISA). The genic interaction was analyzed through dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. In vivo assay was performed in mice. Hypoxia induced the upregulation of circJARID2 expression in H9c2 cells. The hypoxia-induced cell viability inhibition, apoptosis promotion and inflammatory response were all counterbalanced by knockdown of circJARID2. CircJARID2 interacted with miR-9-5p and its function in regulating the hypoxia-induced cell injury was also dependent on targeting miR-9-5p. BNIP3 acted as a target gene of miR-9-5p and circJARID2 had positive effect on BNIP3 expression by binding to miR-9-5p. MiR-9-5p played a protective role for H9c2 cells against the hypoxia-induced injury via targeting BNIP3. CircJARID2 expression was also increased in MI mice. CircJARID2 overexpression contributed to the hypoxia-induced H9c2 cell injury by sponging miR-9-5p to upregulate BNIP3 expression, showing a novel molecular network of MI pathomechanism.

DOI: https://doi.org/10.1097/FJC.0000000000001033
Biomed Res Int. 2021 ;2021 5553486

Experimental Study on the Correlation between miRNA-373 and HIF-1α, MMP-9, and VEGF in the Development of HIE.

Chun-Yang Liu, Hisham Al-Ward, Francine Ngaffo Mekontso, Ning Liu, Hui-Qin Zeng, Min Liu, Zi-Rui Yu, Lin Zhang, Yu-Chun Han, Hui Xu.

Introduction: Microribonucleic acids (miRNAs) have short (approximately 18 to 25) nucleotides and are evolutionarily conserved and endogenously expressed RNAs belonging to a family of noncoding RNA molecules. miRNA-373 regulates cell proliferation, migration, apoptosis, invasion, and repairing damaged DNA after hypoxia stress. Neonatal hypoxic-ischemic encephalopathy (HIE) refers to perinatal asphyxia caused by partial or complete hypoxia, reduced or suspended cerebral blood flow, and fetal or neonatal brain damage. We aim to investigate the relationship between miRNA-373 and HIF-1α, between miRNA-373 MMP-9, and between miRNA-373 VEGF in the occurrence and development of HIE.
Methods: Human (children) samples were divided into four groups (n = 15 in each group) according to HIE severity. The patient group was divided into middle, moderate, and severe HIE groups. The control group included healthy children or children with nonneurological diseases. The expressions of miRNA-373, HIF-1α, MMP-9, and VEGF were assayed in the serum samples.
Results: Our study showed a strong relationship between miRNA-373 and HIF-1α, between miRNA-373 and MMP-9, and between miRNA-373 and VEGF. The expression levels of miRNA-373, HIF-1α, MMP-9, and VEGF in the HIE groups were much higher than those of the control group.
Conclusion: The increased change in miRNA-373 expression has a certain diagnostic significance on neonatal HIE. In the occurrence and development of HIE, miRNA-373 is positively correlated with HIF-1α, MMP-9, and VEGF.

DOI: https://doi.org/10.1155/2021/5553486
Exp Ther Med. 2021 Jul;22(1): 708

Klotho alleviates chronic intermittent hypoxia-induced genioglossus myocyte apoptosis by inhibiting endoplasmic reticulum stress.

Zhen Xue, Wenxiao Ding, Luyao Ge, Qiang Zhang.

  Chronic intermittent hypoxia (CIH) has been shown to induce cell apoptosis in multiple organs of the human body. The present study aimed to assess the effects of exogenous klotho on CIH-induced genioglossus muscle injury, as well as the involvement of endoplasmic reticulum stress (ERS) in this process. A total of 36 adult C57BL/6 male mice were assigned to normoxia control (NC), CIH and CIH + klotho groups (n=12 mice/group). ELISA was performed to detect the level of klotho protein in the serum and in the genioglossus muscle tissue samples. Apoptosis was evaluated using the TUNEL assay. Reactive oxygen species (ROS) levels were quantified using a dihydroethidium assay kit, and the protein and mRNA levels of ERS-associated proteins (namely, glucoseregulated protein 78, C/EBP homologous protein, cleaved caspase-12 and cleaved caspase-3) in genioglossus samples were assessed using immunoblot assay and reverse transcription-quantitative PCR, respectively. Compared with the NC group, the quantities of klotho protein in the serum and genioglossus muscle tissue samples in the CIH group were significantly decreased, whereas the apoptotic rate, ROS levels and protein and mRNA levels of the ERS-associated proteins in the genioglossus muscle were significantly increased. Following supplementation with exogenous klotho protein, the klotho protein levels in the serum and genioglossus muscle tissue of mice were found to be markedly increased, and the apoptotic rate, ROS levels and protein and mRNA levels of the ERS-associated proteins in the genioglossus muscle were decreased compared with those in the CIH group. Taken together, the results of the present study have demonstrated that exogenous klotho may inhibit apoptosis of genioglossus myocytes in mice by inhibiting ROS-associated ERS.

Keywords:  ROS; apoptosis; chronic intermittent hypoxia; endoplasmic reticulum stress; genioglossus muscle; klotho protein

DOI:  https://doi.org/10.3892/etm.2021.10140
Am J Transl Res. 2021 ;13(4): 2283-2295

miR-320-3p regulates the proliferation, migration and apoptosis of hypoxia-induced pulmonary arterial smooth muscle cells via KLF5 and HIF1α.

Dandan Ding, Hongxia Jiang, Yuanzhou He, Xiaochen Li, Xiansheng Liu.

Irreversible pulmonary hypertension (PH) mainly results from vascular remodeling, in which the aberrant growth of pulmonary arterial smooth muscle cells (PASMCs) plays a significant role. Our previous work suggested that KLF5 and HIF1α are closely associated with the pathogenesis of hypoxic PH as they intervene in the growth of PASMCs. MicroRNAs (miRNAs) have been demonstrated to be involved in the control of cell proliferation and apoptosis. In the present study, we detected the expression of six miRNAs connected with KLF5 in hypoxia-exposed rat PH models and PASMCs and then further investigated the role of miR-320-3p in the abnormal proliferation of hypoxic PASMCs and in the progression and treatment outcomes of hypoxia-induced PH. The results indicated that miR-320-3p was downregulated in hypoxia-exposed rat PH models, hypoxia-induced PASMCs and chronic thromboembolic pulmonary hypertension (CTEPH) patients. Moreover, miR-320-3p directly regulated the expression of KLF5 and HIF1α. miR-320-3p mimics inhibited proliferation and migration and promoted apoptosis in hypoxic PASMCs. KLF5 and HIF1α reversed the above effects of miR-320-3p. In conclusion, miR-320-3p plays a certain role in the progression of hypoxic PH via KLF5 and HIF1α and might be a potent therapeutic tool for PH.

Keywords: HIF1α; KLF5; Pulmonary hypertension; miRNA; vascular remodeling
Inflammation. 2021 May 20.

PD-L1 Regulates Inflammation in LPS-Induced Lung Epithelial Cells and Vascular Endothelial Cells by Interacting with the HIF-1α Signaling Pathway.

Shilong Zhao, Jing Gao, Jing Li, Shilei Wang, Congcong Yuan, Qiuhong Liu.

  Sepsis-induced lung injury was the most common cause of death in patients. This study aimed to investigate whether PD-L1 regulates the inflammation in LPS-induced lung epithelial cells and vascular endothelial cells by interacting with the HIF-1α signaling pathway. Sepsis-induced lung injury mice were constructed by cecal ligation and puncture (CLP) procedure, and lipopolysaccharide (LPS)-induced lung epithelial cells and vascular endothelial cells simulate the sepsis-induced lung injury model in vitro. Hematoxylin-eosin (HE) staining detected the morphological changes of the lung tissues, and immunohistochemistry (IHC) detected the PD-L1 expression in lung tissues. Bicinchoninic acid (BCA) assay determined the protein concentration in bronchial alveolar lavage fluid (BALF). The number of PD-1 (+) cells in blood was detected by flow cytometry. The apoptosis in lung tissues and LPS-induced cells was analyzed by TUNEL assay. The inflammatory factor levels and HIF-1α in lung tissues and LPS-induced cells were analyzed by ELISA. The transfection effects of KD-PDL1 or KD-HIF1A in lung epithelial cells and vascular endothelial cells were confirmed by qRT-PCR analysis. The protein expression related to the PD-L1- and HIF-1α-related pathway was determined by Western blot analysis. As a result, LMT-28, as an IL-6 inhibitor, alleviated lung injury and suppressed the apoptosis and inflammation in lung tissues in BALF and the number of PD-1 (+) cells in blood. Sepsis-induced lung injury activated the PD-L1- and HIF-1α-related pathway, while LMT-28 could not completely inhibit the pathway. In addition, downregulation of PD-L1 or downregulation of HIF-1α suppressed the apoptosis and alleviated the inflammation in LPS-induced lung epithelial cells and vascular endothelial cells. Downregulation of PD-L1 had significant effects on lung epithelial cells but had greater effects on vascular endothelial cells. Downregulation of HIF-1α could decrease PD-L1 expression, and downregulation of PD-L1 could also suppress the protein expression of HIF-1α and related pathways. In conclusion, downregulation of PD-L1 alleviated the inflammation in LPS-induced lung epithelial cells and vascular endothelial cells by suppressing the HIF-1α signaling pathway.

Keywords:  HIF-1α signaling pathway; LPS; PD-L1; inflammation; lung epithelial cells; vascular endothelial cells

DOI:  https://doi.org/10.1007/s10753-021-01474-3
Onco Targets Ther. 2021 ;14 3069-3081

Effect of GLUT1 Inhibition and Autophagy Modulation on the Growth and Migration of Laryngeal Carcinoma Stem Cells Under Hypoxic and Low-Glucose Conditions.

Xiao-Hong Chen, Jia Liu, Jiang-Tao Zhong, Shui-Hong Zhou, Jun Fan.

   Background: Enhanced glucose uptake and autophagy are means by which cells adapt to stressful microenvironments. In this study, we investigated the roles of glucose transporter-1 (GLUT-1) and autophagy in laryngeal carcinoma stem cells under hypoxic and low-glucose conditions.
Materials and Methods: CD133-positive Tu212 laryngeal carcinoma stem cells were purified by magnetic-activated cell sorting and subjected to hypoxic and/or low-glucose conditions. Proliferation was evaluated using a cell-counting kit and a clone-formation assay, and migration capability was measured through a Transwell assay. Autophagy was assessed using transmission electron microscopy. Gene silencing was monitored using shRNA technology and autophagy regulation was manipulated using rapamycin, 3-MA, or chloroquine. Gene expression levels were evaluated by quantitative reverse transcription-polymerase chain reaction and protein levels were assessed via Western blotting.
Results: Compared to CD133-negative cells, CD133-positive cells showed increased proliferation and migration capabilities, and reduced apoptosis, under hypoxic or low-glucose conditions. CD133-positive cells also showed increased expression of GLUT-1 and autophagy activity. Finally, GLUT-1 knockdown or autophagy inhibition reduced the proliferation and migration of CD133-positive laryngeal carcinoma stem cells.
Conclusion: Enhanced glucose uptake and autophagy maintain the tumor behaviors of CD133-positive laryngeal carcinoma stem cells under hypoxic and low-glucose conditions.

Keywords:  CD133-positive cell; GLUT-1; Laryngeal carcinoma; autophagy; cancer stem cell

DOI:  https://doi.org/10.2147/OTT.S300423
J Cell Sci. 2020 Jan 01. pii: jcs.250274. [Epub ahead of print]

Protein tyrosine phosphatase-PEST mediates hypoxia-induced endothelial autophagy and angiogenesis via AMPK activation.

Shivam Chandel, Amrutha Manikandan, Nikunj Mehta, Abel Arul Nathan, Rakesh Kumar Tiwari, Samar Bhallabha Mohapatra, Mahesh Chandran, Abdul Jaleel, Narayanan Manoj, Madhulika Dixit.

  Global and endothelial loss of PTP-PEST is associated with impaired cardiovascular development and embryonic lethality. Although hypoxia is implicated in vascular remodelling and angiogenesis, its effect on PTP-PEST remains unexplored. Here we report that hypoxia (1 % oxygen) increases protein levels and catalytic activity of PTP-PEST in primary endothelial cells. Immunoprecipitation followed by mass spectrometry (LC/MS/MS) revealed that alpha subunits of AMPK (α1 and α2) interact with PTP-PEST under normoxia but not in hypoxia. Co-immunoprecipitation experiments confirmed this observation and determined that AMPK α subunits interact with the catalytic domain of PTP-PEST. Knockdown of PTP-PEST abrogated hypoxia mediated tyrosine dephosphorylation and activation of AMPK (Thr172 phosphorylation). Absence of PTP-PEST also blocked hypoxia-induced autophagy (LC3 degradation and puncta formation) which was rescued by AMPK activator, metformin (500 µM). Since endothelial autophagy is a pre-requisite for angiogenesis, knockdown of PTP-PEST also attenuated endothelial cell migration and capillary tube formation with autophagy inducer rapamycin (200 nM) rescuing angiogenesis. In conclusion, this work identifies for the first time PTP-PEST as a regulator of hypoxia-induced AMPK activation and endothelial autophagy to promote angiogenesis.

Keywords:  AMPK; Angiogenesis; Autophagy; Hypoxia; PTP-PEST

DOI:  https://doi.org/10.1242/jcs.250274
ACS Chem Neurosci. 2021 May 20.

The Protective Effects of Dexmedetomidine against Hypoxia/Reoxygenation-Induced Inflammatory Injury and Permeability in Brain Endothelial Cells Mediated by Sigma-1 Receptor.

Qin Zhao, Shoushui Yu, Yong Ling, Shiyuan Hao, Jia Liu.

  Cerebral ischemia-reperfusion injury (CIRI) mainly arises from the clinical treatment of ischemic stroke, induced by the blood-brain barrier (BBB) disruption and infiltrated inflammation. The Sigma-1 receptor (Sigma-1R) is a novel target for neuroprotection, and the α2-receptor agonist pain medication dexmedetomidine displays a neuroprotective effect through activating Sigma-1R. The present study aims to investigate the potential therapeutic effect of dexmedetomidine in a mouse stroke model and hypoxia/reoxygenation(OGD/R)-induced brain endothelial dysfunction. First, we found that Sigma-1R was significantly upregulated in middle cerebral artery occlusion (MCAO) mice by the administration of dexmedetomidine. In vivo experiments revealed that dexmedetomidine ameliorated hyperpermeability of the blood-brain barrier (BBB), lowered the expression level of Occludin, and impaired brain function as measured by neurological scores in MCAO mice. In vitro assays show that dexmedetomidine alleviated OGD/R-caused cytotoxicity, hyperpermeability, abnormal expression of Occludin, and inflammatory factors in human brain microvascular endothelial cells (HBMVECs). Moreover, blockage of Sigma-1R by its antagonist BD1047 abolished the neuroprotective property of dexmedetomidine in both animal and cell culture experiments. On the basis of these findings, we conclude that dexmedetomidine therapy shows neuroprotection in MCAO mice. Mechanistically, dexmedetomidine alleviated hypoxia/reoxygenation-induced cerebral endothelial dysfunction by activating the Sigma-1R-mediated signaling pathway.

Keywords:  BBB; MCAO; Occludin; Sigma-1 receptor (Sigma-1R); Stroke; hypoxia/reoxygenation(OGD/R)

DOI:  https://doi.org/10.1021/acschemneuro.1c00032
EMBO Rep. 2021 May 17. e52013

TRPV1 sustains microglial metabolic reprogramming in Alzheimer's disease.

Jia Lu, Wei Zhou, Fangfang Dou, Chenfei Wang, Zhihua Yu.

  As the brain-resident innate immune cells, reactive microglia are a major pathological feature of Alzheimer's disease (AD). However, the exact role of microglia is still unclear in AD pathogenesis. Here, using metabolic profiling, we show that microglia energy metabolism is significantly suppressed during chronic Aβ-tolerant processes including oxidative phosphorylation and aerobic glycolysis via the mTOR-AKT-HIF-1α pathway. Pharmacological activation of TRPV1 rescues Aβ-tolerant microglial dysfunction, the AKT/mTOR pathway activity, and metabolic impairments and restores the immune responses including phagocytic activity and autophagy function. Amyloid pathology and memory impairment are accelerated in microglia-specific TRPV1-knockout APP/PS1 mice. Finally, we showed that metabolic boosting with TRPV1 agonist decreases amyloid pathology and reverses memory deficits in AD mice model. These results indicate that TRPV1 is an important target regulating metabolic reprogramming for microglial functions in AD treatment.

Keywords:  TRPV1; autophagy; capsaicin; metabolism; microglia

DOI:  https://doi.org/10.15252/embr.202052013
Cell Mol Biol Lett. 2021 May 18. 26(1): 19

Worenine reverses the Warburg effect and inhibits colon cancer cell growth by negatively regulating HIF-1α.

Lijiang Ji, Weixing Shen, Feng Zhang, Jie Qian, Jie Jiang, Liping Weng, Jiani Tan, Liu Li, Yugen Chen, Haibo Cheng, Dongdong Sun.

   BACKGROUND: Some natural compounds inhibit cancer cell growth in various cancer cell lines with fewer side effects than traditional chemotherapy. Here, we explore the pharmacological effects and mechanisms of worenine (isolated from Coptis chinensis) against colorectal cancer.
METHODS: The effects of worenine on colorectal cancer cell proliferation, colony formation and cell cycle distribution were measured. Glycolysis was investigated by examining glucose uptake and consumption, lactate production, and the activities and expressions of glycolysis enzymes (PFK-L, HK2 and PKM2). HIF-1α was knocked down and stimulated in vitro to investigate the underlying mechanisms.
RESULTS: Worenine somewhat altered the glucose metabolism and glycolysis (Warburg effect) of cancer cells. Its anti-cancer effects and capability to reverse the Warburg effect were similar to those of HIF-1α siRNA and weakened by deferoxamine (an HIF-1α agonist).
CONCLUSION: It is suggested that worenine targets HIF-1α to inhibit colorectal cancer cell growth, proliferation, cell cycle progression and the Warburg effect.

Keywords:  Colon cancer; Glycolysis; HIF-1α; Warburg effect; Worenine

DOI:  https://doi.org/10.1186/s11658-021-00263-y
Med Pharm Rep. 2021 Apr;94(2): 197-207

Neuronal apoptosis can be prevented by the combined therapy with melatonin and hypothermia in a neonatal rat model of hypoxic-ischemic encephalopathy.

Alina Mihaela Toader, Oana Hoteiuc, Cristina Bidian, Dan-Daniel Oltean, Flaviu Tabaran, Ovidiu Grad, Simona Clichici, Daniela Rodica Mitrea.

   Introduction: Birth hypoxia is a leading cause of perinatal mortality and neurological morbidity, resulting in central nervous system injury. Cerebral hypoxia and ischemia can produce a severe brain damage following a typical pattern, defined by selective vulnerability of the brain regions. The neonates are most prone to hypoxic-ischemic injuries due to the lack of efficient antioxidant defense. Neonatal hypoxia-ischemia (HI) in a 7-day-old rat HI model can produce cell death by apoptotic or necrotic mechanisms. The degree of apoptotic or necrotic mechanisms responsible for cell death in neonatal hypoxia-ischemia are not very clear as yet. The form of neuronal death may also depend on the severity of ischemic injury. Necrosis predominates in more severe cases, whereas apoptosis occurs in areas with milder ischemic injury. A human study demonstrated apoptotic and necrotic forms of cell death after hypoxic injury, whereas in some brains from stillbirths, only apoptotic figures were observed. The expression of activated caspase-3 reflects the role of apoptosis in neonatal hypoxic ischemic brain injury.
Objectives: The aim of this study was to evaluate the possible neuroprotective effect of melatonin and hypothermia in hypoxic-ischemic encephalopathy in newborn rats. Local damages induced by hypoxia and ischemia were assessed by evaluating the changes in terms of histology and apoptosis.
Methods: The experiment was conducted on 20 newborn Wistar rats premedicated for seven days with melatonin in a dose of 20 mg/kg/day. On the 7th postnatal day (P7), the newborn rats were exposed to ischemia (by clamping the right carotid artery) and hypobaric hypoxia (8% O2 for 90 minutes) and some groups to hypothermia.
Results: In this experimental model of neonatal encephalopathy, melatonin, in a dose of 20 mg/kg/day has neuroprotective effect by reducing the number of cells expressing apoptosis in Cornu Ammonis (CA) (Ammon's Horn) CA1, CA2, CA3 and dentate gyrus of the hippocampus when combined with hypothermia.
Conclusion: The results of this study prove that melatonin is protective in ischemic-hypoxic brain injuries, but the protection is conditioned in most of the brain regions (excepting cerebral cortex) by conjugation with post-injury hypothermia treatment.

Keywords:  apoptosis; hypothermia; hypoxic-ischemic encephalopathy; melatonin; neuroprotection

DOI:  https://doi.org/10.15386/mpr-1903