bims-hypoxi 2021-08-15 papers

bims-hypoxi

Biomed News

on Hypoxia and HIF1-alpha

Issue of 2021–08–15
24 papers selected by

ERK signalling controls productive HIF-1 binding to chromatin and cancer cell adaptation to hypoxia through HIF-1α interaction with NPM1.
Hypoxia inducible factor 1-α is minimally involved in determining the time domains of the hypoxic ventilatory response in adult zebrafish (Danio rerio).
Hypoxic Hepatocellular Carcinoma Cells Acquire Arsenic Trioxide Resistance by Upregulating HIF-1α Expression.
Targeting the HIF-1α/Cav-1 pathway with a chicory extract/daidzein combination plays a potential role in retarding hepatocellular carcinoma.
JMJD5 attenuates oxygen-glucose deprivation and reperfusion-induced injury in cardiomyocytes through regulation of HIF-1α-BNIP3.
Effects of remote ischemic postconditioning on HIF-1α and other markers in on-pump cardiac surgery.
Indispensable Role of HIF-1α Signaling in Post-implantation Survival and Angio-/Vasculogenic Properties of SHED.
Hyperbaric Oxygen Therapy Represses the Warburg Effect and Epithelial-Mesenchymal Transition in Hypoxic NSCLC Cells via the HIF-1α/PFKP Axis.
Carbonic Anhydrase III Attenuates Hypoxia-Induced Apoptosis and Activates PI3K/Akt/mTOR Pathway in H9c2 Cardiomyocyte Cell Line.
The Role of Macrophage Migration Inhibitory Factor in Adipose-Derived Stem Cells Under Hypoxia.
Panax notoginseng saponins reduces the cisplatin-induced acute renal injury by increasing HIF-1α/BNIP3 to inhibit mitochondrial apoptosis pathway.
Hypoxia facilitates the proliferation of colorectal cancer cells by inducing cancer-associated fibroblast-derived IL6.
Effects of detraining on preconditioning exercise-induced neuroprotective potential after ischemic stroke in rats.
NAD+ metabolism controls growth inhibition by HIF1 in normoxia and determines differential sensitivity of normal and cancer cells.
Modulation of cell physiology under hypoxia in pancreatic cancer.
Hypoxia boosts aerobic glycolysis of carcinoma：a complex process for tumor development.
Triple therapy with osimertinib, bevacizumab and cetuximab in EGFR-mutant lung cancer with HIF-1α/TGF-α expression.
Autophagy-Related LC3 Accumulation Interacted Directly With LIR Containing RIPK1 and RIPK3, Stimulating Necroptosis in Hypoxic Cardiomyocytes.
Hypoxia increases melanoma-associated fibroblasts immunosuppressive potential and inhibitory effect on T cell-mediated cytotoxicity.
Hypoxia-responsive expression of vascular endothelial growth factor for induction of angiogenesis in artificial three-dimensional tissues.
Long non-coding RNA VCAN-AS1 promotes the malignant behaviors of breast cancer by regulating the miR-106a-5p-mediated STAT3/HIF-1α pathway.
Evaluation of 18F-EF5 for detection of hypoxia in localized adenocarcinoma of the prostate.
Hypoxia preconditioned bone marrow-derived mesenchymal stromal/stem cells enhance myoblast fusion and skeletal muscle regeneration.
[Silencing LncRNA SNHG7 alleviates hypoxia/reoxygenation-induced cardiomyocyte damage by regulating the expression of miR-181b-5p].

Mol Oncol. 2021 Aug 13.

ERK signalling controls productive HIF-1 binding to chromatin and cancer cell adaptation to hypoxia through HIF-1α interaction with NPM1.

Kreon Koukoulas, Antonis Giakountis, Angeliki Karagiota, Martina Samiotaki, George Panayotou, George Simos, Ilias Mylonis.

  The hypoxia-inducible factor HIF-1 is essential for oxygen homeostasis. Despite its well-understood oxygen-dependent expression, regulation of its transcriptional activity remains unclear. We show that phosphorylation by ERK1/2, in addition to promoting HIF-1α nuclear accumulation, also enhances its interaction with chromatin and stimulates direct binding to nucleophosmin (NPM1), a histone chaperone and chromatin remodeler. NPM1 is required for phosphorylation-dependent recruitment of HIF-1 to hypoxia-response elements (HREs), its interaction with acetylated histones and high expression of HIF-1 target genes under hypoxia. Transcriptome analysis revealed a significant number of hypoxia-related genes commonly regulated by NPM1 and HIF-1. These NPM1/HIF-1α co-upregulated genes are enriched in three different cancer types and their expression correlates with hypoxic tumor status and worse patient prognosis. In concert, silencing of NPM1 expression or disruption of its association with HIF-1α inhibits metabolic adaptation of cancer cells and triggers apoptotic death upon hypoxia. We suggest that ERK-mediated phosphorylation of HIF-1α regulates its physical interaction with NPM1, which is essential for productive association of HIF-1 with hypoxia target genes and their optimal transcriptional activation, required for survival under low oxygen or tumor growth.

Keywords:  Cancer; HIF; Hypoxia; NPM1; Nucleophosmin

DOI:  https://doi.org/10.1002/1878-0261.13080
Respir Physiol Neurobiol. 2021 Aug 07. pii: S1569-9048(21)00159-2. [Epub ahead of print] 103774

Hypoxia inducible factor 1-α is minimally involved in determining the time domains of the hypoxic ventilatory response in adult zebrafish (Danio rerio).

Milica Mandic, Adrian Bailey, Steve F Perry.

  In the current study, adult zebrafish (Danio rerio) were exposed to 72 h hypoxia (90 mmHg) to assess the time domains of the hypoxia ventilatory response (HVR) and the consequence on a subsequent more severe (40 mmHg) bout of acute hypoxia. Experiments were performed on wild-type fish and mutants in which one or both paralogs of hypoxia inducible factor-1α (hif-1α) were knocked out. Although there were subtle differences among the wild-type and knockout fish, resting fV was reestablished after 2 - 8 h of continuous hypoxia in both groups, a striking example of hypoxic ventilatory decline (HVD). When fish were subsequently exposed to more severe hypoxia, a rapid increase in fV was observed, the magnitude of which was independent of genotype or prior exposure history. During recovery, fish that had been exposed to 72 h of 90 mmHg hypoxia exhibited a pronounced undershoot in fV, which was absent in the hif-1α double knockouts. Overall, the results revealed distinct time domains of the HVR in zebrafish that were largely Hif-1α-independent.

Keywords:  Hypoxic ventilatory response (HVR); control of breathing; gene knockout; hypoxia inducible factor-1α; hypoxic ventilatory decline; zebrafish

DOI:  https://doi.org/10.1016/j.resp.2021.103774
Dig Dis Sci. 2021 Aug 12.

Hypoxic Hepatocellular Carcinoma Cells Acquire Arsenic Trioxide Resistance by Upregulating HIF-1α Expression.

Yaoting Chen, Huiqing Li, Dong Chen, Xiongying Jiang, Weidong Wang, Dan Li, Hong Shan.

   BACKGROUND: Although arsenic trioxide (ATO) is used in the treatment of advanced hepatocellular carcinoma (HCC) in clinical trials, it is not satisfactory in terms of improving HCC patients' overall survival. Intratumoral hypoxia and overexpression of hypoxia-inducible factor-1α (HIF-1α) may result in ATO resistance and tumor progression.
AIMS: We investigated the mechanisms involving HIF-1α expression and acquired ATO chemoresistance in HCC cells and mice.
METHODS: The therapeutic effects of ATO in normoxic and hypoxic HCC cells were assessed using cell viability and apoptosis assays in vitro and a xenograft model in vivo. mRNA and protein expression of HIF-1α, P-glycoprotein, and VEGF were measured by qRT-PCR and western blotting. HIF-1α inhibition was performed to investigate the mechanism of ATO resistance. VEGF secretion was tested using ELISA and tube formation assays.
RESULTS: Compared to normoxic cells, hypoxic HCC cells were more resistant to ATO, with higher IC50 values and less apoptosis, and upregulated HIF-1α protein expression, accompanied with the enhancement of P-glycoprotein and VEGF synthesis after ATO treatment. VEGF secretion was elevated in the supernatant of ATO-treated HCC cells, and this change can potentiate angiogenesis in vitro. HIF-1α inhibition attenuated ATO resistance and angiogenesis and promoted the anticancer effects of ATO both in vitro and in vivo by downregulating therapy-induced P-glycoprotein and VEGF overexpression.
CONCLUSIONS: Hypoxic HCC cells acquire ATO resistance by upregulating HIF-1α levels; thus, combining ATO with a HIF-1α-targeting agent may lead to enhanced antitumor effects in HCC.

Keywords:  Arsenic trioxide; Drug resistance; HIF-1α; Hepatocellular carcinoma; Targeted therapy

DOI:  https://doi.org/10.1007/s10620-021-07202-z
Curr Cancer Drug Targets. 2021 Aug 11.

Targeting the HIF-1α/Cav-1 pathway with a chicory extract/daidzein combination plays a potential role in retarding hepatocellular carcinoma.

Sherin Zakaria, Reem Nawaya, Nabil M Abdel-Hamid, Ramadan A Eldomany, Mamdouh M El-Shishtawy.

   BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most rapidly growing solid cancers, that is characterized by hypoxia. Hypoxia-inducible factor-1α (HIF-1α) is a transcription factor that regulates tumor proliferation and metastasis. It induces caveolin-1 (Cav-1) expression, a glycoprotein found on the membrane surface, then Cav-1 triggers angiogenesis and metastasis in HCC.
OBJECTIVES: We hypothesize that targeting HIF-1α and consequently, Cav-1 using the antioxidant natural compound such as chicoric acid and a Cav-1 inhibitor daidzein (DAZ) could be a useful approach in the management of HCC. This study was conducted to investigate the possible therapeutic efficacy of standardized chicory leaf extract (SCLE) and DAZ via modulation of HIF-1α and Cav-1 in HCC rats.
METHOD: Diethyl nitrosamine (DENA) was used for HCC induction. After the induction period, four groups (10 rats for each) were treated with SCLE, DAZ, a combination of both, as well as sorafenib, all compared to the non-treated control. We assessed hepatic HIF-1α protein expression, Cav-1 gene expression, serum level of AFP, hepatic tissue content of VEGF, MMP-9, oxidative stress markers MDA and SOD.
RESULTS: DAZ, SCLE, and their combination, significantly down-regulated the expression of HIF-1α, Cav-1, and consequently dampened MMP-9, VEGF, hepatic content. It is noted that the combination treatment showed a synergistic effect compared to either treatment alone. Importantly, the combination treatment exhibited a significantly more potent effect than sorafenib.
CONCLUSION: This study showed the potential role of the HIF-1α/Cav-1 pathway in HCC progression, moreover, SCLE and DAZ showed a potent efficacy in retarding HCC via modulation of this pathway.

Keywords:  Chicory leaf extract; Daidzein; Diethyl nitrosamine; Hepatocellular carcinoma; Hypoxia-inducible factor-1α; caveolin-1.

DOI:  https://doi.org/10.2174/1568009621666210811121120
Kaohsiung J Med Sci. 2021 Aug 09.

JMJD5 attenuates oxygen-glucose deprivation and reperfusion-induced injury in cardiomyocytes through regulation of HIF-1α-BNIP3.

Ya-Nan Zhang, Ya-Xiang Pang, Da-Wei Liu, Hai-Juan Hu, Rui-Qin Xie, Wei Cui.

  Proteins in Jumonji family function as histone demethylases and participate in cardiac development. Jumonji domain containing 5 (JMJD5) is responsible for the embryonic development through removing methyl moieties from H3K36me2 histone, and has pro-proliferative effect on heart and eye development. However, the protective role of JMJD5 against oxygen-glucose deprivation and reperfusion (OGD/R)-induced injury in cardiomyocytes has not been fully understood. Firstly, myocardial ischemia/reperfusion (I/R) rat model was established by ligation of left coronary artery. OGD/R was performed in non-transfected H9C2 or H9C2 transfected with pcDNA-JMJD5 plasmid to induce cell cytotoxicity. Data from qRT-PCR and western blot showed that JMJD5 was reduced in the heart tissues of myocardial I/R rat model and OGD/R-induced H9C2. Secondly, JMJD5 over-expression attenuated OGD/R-induced decrease in cell viability and increase in lactate dehydrogenase secretion and cell apoptosis in H9C2. Mitophagy was promoted by pcDNA-mediated over-expression of JMJD5 with enhanced protein expression of LC3-I, LC3-II, Atg5, and Beclin 1. Thirdly, knockdown of JMJD5 aggravated OGD/R-induced decrease in hypoxia-inducible factor-1α (HIF-1α), whereas JMJD5 over-expression enhanced BNIP3 (Bcl-2/adenovirus E1B 19-kDa interacting protein) through upregulation of HIF-1α. Lastly, BNIP3 silencing promoted cell apoptosis, suppressed mitophagy, and attenuated the protective effects of JMJD5 over-expression against OGD/R-induced injury in H9C2. In conclusion, JMJD5 exerted protective effects against OGD/R-induced injury in cardiomyocytes through upregulation of HIF-1α-BNIP3.

Keywords:  BNIP3; JMJD5; OGD/R; apoptosis; mitophagy

DOI:  https://doi.org/10.1002/kjm2.12434
Gen Thorac Cardiovasc Surg. 2021 Aug 10.

Effects of remote ischemic postconditioning on HIF-1α and other markers in on-pump cardiac surgery.

José García-de-la-Asunción, Tania Moreno, Alejandro Duca, Nuria García-Del-Olmo, Jaume Perez-Griera, Javier Belda, Marina Soro, Eva García-Del-Olmo.

   BACKGROUND: There is a lack of data about the effects of remote ischemic postconditioning (RIPostC) on hypoxia-inducible factor-1α (HIF-1α) plasma levels after on-pump cardiac surgery (OPCS). This study aimed to measure the effects of RIPostC on postoperative HIF-1α plasma levels, cardiac markers and arterial oxygenation in patients undergoing OPCS.
METHODS: This single-centre randomized, double blind, controlled trial, enrolled 70 patients (35 control and 35 RIPostC). RIPostC was performed by 3 cycles (5 min of ischemia followed by 5 min of reperfusion) administered in upper arm immediately after the pump period. The primary outcome was to measure HIF-1α plasma levels: before surgery (T0), and 2 h (T1), 8 h (T2), 24 h (T3), 36 h (T4) and 48 h (T5) after RIPostC. As secondary endpoint, Troponin T, CK-MB, CPK plasma levels and PaO2/FiO2 ratio were measured.
RESULTS: HIF-1α plasma levels were increased at T1-T3 compared to T0 in both groups (P < 0.001). In the RIPostC group HIF-1α increased compared to the control group: differences between means (95% CI) were 0.034 (0.006-0.06) P = 0.019 at T1; 0.041 (0.013-0.069) P = 0.005 at T2; and 0.021 (0.001-0.042) P = 0.045 at T3. PaO2/FiO2 was higher in the RIPostC group than in the control group: at T3, T4 and T5. Moreover, Troponin T, CK-MB and CPK values decreased in the RIPostC group compared to the control group.
CONCLUSIONS: HIF-1α plasma levels increased in control patients during for at least 36 h after OPCS. RIPostC resulted in even higher HIF-1α levels during at least the first 24 h and improved arterial oxygenation and cardiac markers.

Keywords:  Cardiopulmonary bypass; Hypoxia-induced factor-1α; Ischemia; On-pump cardiac surgery; Remote ischemic postconditioning; Reperfusion

DOI:  https://doi.org/10.1007/s11748-021-01690-6
Front Cell Dev Biol. 2021 ;9 655073

Indispensable Role of HIF-1α Signaling in Post-implantation Survival and Angio-/Vasculogenic Properties of SHED.

Yuanyuan Han, Qixin Chen, Lili Zhang, Waruna Lakmal Dissanayaka.

   Objectives: Post-implantation survival and timely vascularization of stem-cell based constructs are critical factors in achieving successful outcomes in tissue regeneration approaches. Hypoxia inducible factor-1α (HIF-1α) is known to mediate adaptive functions to ischemic stress in many different cell types. The current study aimed to explore the role of HIF-1α in post-implantation survival and angio-/vasculogenesis of stem cells from human exfoliated deciduous teeth (SHED).
Methods: HIF-1α in SHED was suppressed using siRNA or chemical inhibitor (YC-1) and used in Matrigel plug assay conducted on severe combined immunodeficient mice. The plugs were retrieved on day 3 or 7 post-injection and analyzed for hypoxia status, ki67 expression, DNA fragmentation (TUNEL), cellularity, and vascularization by histology and immunohistochemistry for CD31, HIF-1α, pyruvate dehydrogenase kinase-1 (PDK1), hexokinase 2 (HK2), and glucose transporter 1 (Glut1). Cell viability of HIF-1α silenced SHED under different stress conditions (hypoxia, H2O2, and low glucose) in vitro was measured by CCK-8 assay. CM-H2DCFDA and MitoSOX Red were used to detect cellular and mitochondrial reactive oxygen species (ROS) levels, respectively. PDK1, HK2, and Glut1 expression were measured by western blotting and immunofluorescence. Secretory protein levels of vascular endothelial growth factor (VEGF) and the respective paracrine effects on endothelial cell proliferation and migration were detected by ELISA, CCK-8 assay, and trans-well assay, respectively.
Results: Histological analysis of Matrigel plugs showed significantly reduced cell survival in HIF-1α silenced or chemically inhibited SHED groups, which could be attributed to diminished metabolic adaptations as shown by decreased PDK1, HK2, and Glut1 expression. HIF-1α inhibition in SHED also resulted in significantly low blood vessel formation as observed by a low number of perfused and non-perfused vessels of human or mouse CD31 origin. The viability of HIF-1α silenced SHED was significantly affected under hypoxia, H2O2, and low-glucose conditions in vitro, which was reflected in increased cytoplasmic and mitochondrial ROS levels. Significantly reduced levels of VEGF in HIF-1α silenced SHED resulted in decreased paracrine angiogenic effects as shown by low proliferation and migration of endothelial cells.
Conclusion: HIF-1α plays an indispensable role in post-implantation survival and angio-/vasculogenic properties of SHED by maintaining ROS homeostasis, inducing metabolic adaptations, and VEGF secretion.

Keywords:  HIF-1α; cell metabolism; dental stem cells; post-implantation survival; redox balance; regenerative medicine

DOI:  https://doi.org/10.3389/fcell.2021.655073
Front Oncol. 2021 ;11 691762

Hyperbaric Oxygen Therapy Represses the Warburg Effect and Epithelial-Mesenchymal Transition in Hypoxic NSCLC Cells via the HIF-1α/PFKP Axis.

Linling Zhang, Jingjing Ke, Shengping Min, Nan Wu, Fei Liu, Zhen Qu, Wei Li, Hongtao Wang, Zhongqing Qian, Xiaojing Wang.

   Background: Tumor cells initiate hypoxia-induced mechanisms to fuel cell proliferation, invasion, and metastasis, largely mediated by low O2-responsive Hypoxia-Inducible Factor 1 Alpha (HIF-1α). Therefore, hyperbaric oxygen therapy (HBO) is now being studied in cancer patients, but its impact upon non-small-cell lung cancer (NSCLC) cell metabolism remains uncharacterized.
Methods: We employed the NSCLC cell lines A549 and H1299 for in vitro studies. Glucose uptake, pyruvate, lactate, and adenosine triphosphate (ATP) assays were used to assess aerobic glycolysis (Warburg effect). A quantitative glycolytic flux model was used to analyze the flux contributions of HIF-1α-induced glucose metabolism genes. We used a Lewis lung carcinoma (LLC) murine model to measure lung tumorigenesis in C57BL/6J mice.
Results: HBO suppressed hypoxia-induced HIF-1α expression and downstream HIF-1α signaling in NSCLC cells. One HIF-1α-induced glucose metabolism gene-Phosphofructokinase, Platelet (PFKP)-most profoundly enhanced glycolytic flux under both low- and high-glucose conditions. HBO suppressed hypoxia-induced PFKP transactivation and gene expression via HIF-1α downregulation. HBO's suppression of the Warburg effect, suppression of hyperproliferation, and suppression of epithelial-to-mesenchymal transition (EMT) in hypoxic NSCLC cell lines is mediated by the HIF-1α/PFKP axis. In vivo, HBO therapy inhibited murine LLC lung tumor growth in a Pfkp-dependent manner.
Conclusions: HBO's repression of the Warburg effect, repression of hyperproliferation, and repression of EMT in hypoxic NSCLC cells is dependent upon HIF-1α downregulation. HIF-1α's target gene PFKP functions as a central mediator of HBO's effects in hypoxic NSCLC cells and may represent a metabolic vulnerability in NSCLC tumors.

Keywords:  HBO; HIF-1; NSCLC; Warburg effect; hyperbaric oxygen; lung cancer

DOI:  https://doi.org/10.3389/fonc.2021.691762
Cardiovasc Toxicol. 2021 Aug 13.

Carbonic Anhydrase III Attenuates Hypoxia-Induced Apoptosis and Activates PI3K/Akt/mTOR Pathway in H9c2 Cardiomyocyte Cell Line.

Hua Li, Yibin Liu, Sha Tang, Jie Hu, Qiuling Wu, Yang Wei, Ming Niu.

  Myocardial ischemia can cause insufficient oxygen and functional damage to myocardial cells. Carbonic anhydrase III (CAIII) has been found to be closely related to the abnormality of cardiomyocytes. To investigate the role of CAIII in the apoptosis of myocytes under hypoxic conditions and facilitate the strategy for treating hypoxia-induced damage, in vitro experiments in H9c2 were employed. The protein expression of CAIII in H9c2 cells after hypoxia or normoxia treatment was determined by western blotting and immunohistochemistry. MTT assay was employed for cells viability measurement and LDH release was monitored. The apoptotic cells were observed using immunofluorescence assay, flow cytometric analysis, and TUNEL assay. CAIII-overexpression or -knockdown cells were constructed to determine the role of CAIII in regulating apoptosis-related proteins caspase-3, Bax, Bcl-2, and anti-apoptosis pathway PI3K/Akt/mTOR. The mRNA levels of CAIII and genes related to CAIII synthesis including REN, IGHM, APOBEC 3F, and SKOR2 were significantly upregulated in hypoxia fetal sheep. The expression of CAIII protein and content of apoptotic H9c2 cells were increased at 1, 3, 6, and 12 h after hypoxia treatment. Overexpression of CAIII significantly upregulated Bcl2 level and downregulated Bax and caspase-3 cleavage levels, while its knockdown led to the contrary results. Overexpressed CAIII promoted the HIF-1α level and activated the PI3K/Akt/mTOR pathway, thereby exerting an inhibitory effect on hypoxia-induced apoptosis. In conclusion, our findings revealed that CAIII could protect cell from hypoxia-apoptosis of H9c2 cells, in which, activated PI3K/Akt/mTOR signaling pathway may be involved.

Keywords:  Apoptosis; CAIII; H9c2 cells; Hypoxia; PI3K/Akt/mTOR

DOI:  https://doi.org/10.1007/s12012-021-09683-w
Front Physiol. 2021 ;12 638448

The Role of Macrophage Migration Inhibitory Factor in Adipose-Derived Stem Cells Under Hypoxia.

Elena Hofmann, Josefin Soppert, Tim Ruhl, Epameinondas Gousopoulos, Simona Gerra, Gabriele Storti, Yuan Tian, Markus Brandhofer, Riccardo Schweizer, Seung-Yong Song, Nicole Lindenblatt, Norbert Pallua, Jürgen Bernhagen, Bong-Sung Kim.

  Background: Adipose-derived stem cells (ASCs) are multipotent mesenchymal stem cells characterized by their strong regenerative potential and low oxygen consumption. Macrophage migration inhibitory factor (MIF) is a multifunctional chemokine-like cytokine that is involved in tissue hypoxia. MIF is not only a major immunomodulator but also is highly expressed in adipose tissue such as subcutaneous adipose tissue of chronic non-healing wounds. In the present study, we investigated the effect of hypoxia on MIF in ASCs isolated from healthy versus inflamed adipose tissue. Methods: Human ASCs were harvested from 17 patients (11 healthy adipose tissue samples, six specimens from chronic non-healing wounds). ASCs were treated in a hypoxia chamber at <1% oxygen. ASC viability, MIF secretion as well as expression levels of MIF, its receptor CD74, hypoxia-inducible transcription factor-1α (HIF-1α) and activation of the AKT and ERK signaling pathways were analyzed. The effect of recombinant MIF on the viability of ASCs was determined. Finally, the effect of MIF on the viability and production capacity of ASCs to produce the inflammatory cytokines tumor necrosis factor (TNF), interleukin (IL)-6, and IL-1β was determined upon treatment with recombinant MIF and/or a blocking MIF antibody. Results: Hypoxic treatment inhibited proliferation of ASCs derived from healthy or chronic non-healing wounds. ASCs from healthy adipose tissue samples were characterized by a low degree of MIF secretion during hypoxic challenge. In contrast, in ASCs from adipose tissue samples of chronic non-healing wounds, secretion and expression of MIF and CD74 expression were significantly elevated under hypoxia. This was accompanied by enhanced ERK signaling, while AKT signaling was not altered. Recombinant MIF did stimulate HIF-1α expression under hypoxia as well as AKT and ERK phosphorylation, while no effect on ASC viability was observed. Recombinant MIF significantly reduced the secretion of IL-1β under hypoxia and normoxia, and neutralizing MIF-antibodies diminished TNF-α and IL-1β release in hypoxic ASCs. Conclusions: Collectively, MIF did not affect the viability of ASCs from neither healthy donor site nor chronic wounds. Our results, however, suggest that MIF has an impact on the wound environment by modulating inflammatory factors such as IL-1β.

Keywords:  adipose-derived stem cells; chronic wounds; cytokine; hypoxia; macrophage migration inhibitory factor

DOI:  https://doi.org/10.3389/fphys.2021.638448
Biomed Pharmacother. 2021 Aug 09. pii: S0753-3322(21)00747-2. [Epub ahead of print]142 111965

Panax notoginseng saponins reduces the cisplatin-induced acute renal injury by increasing HIF-1α/BNIP3 to inhibit mitochondrial apoptosis pathway.

Qingqing Li, Yansong Zhang, Yufang Yang, Songqing Huang, Xiaoqin Zou, Congying Wei, Taolin Liang, Xiaobin Zhong.

  Cisplatin (CDDP) may induce apoptosis of renal tubular epithelial cells (RTEC) and cause CDDP-induced acute kidney injury (CAKI) during cancer treatment, but yet lack of preventive measures and effective treatment. As a new Chinese herbal preparation, Panax notoginseng saponins (PNS) has been found to mitigate CDDP-induced CAKI through elevating the expression of HIF-1α in the rat model, according to the data from our previous works. However, the underlying link between HIF-1α and apoptosis has not been well elucidated. The current study as a follow-up work, was aimed to reveal if PNS improves CAKI through HIF-1α-dependent apoptosis. A stably HIF-1α-knockdown human proximal tubular epithelial cell (HK-2) line was established by transfecting a HIF-1α-siRNA into HK-2 cells. Cell viability, mitochondrial function, cell apoptosis ratio and the expression of apoptosis-associated proteins (Cyt C, Bcl2, Bax, caspases 3) were determined. In order to elucidate the underlying mechanism, the expression of HIF-1α and BNIP3 were assessed. Our results showed that treatment of PNS rescued the cell viability of CDDP-injured HK-2 or HIF-1α-knockdown HK-2 cells, and increased the expression levels of ATP and MMP in HK-2 or HIF-1α-knockdown HK-2 cells which were reduced by CDDP. Moreover, PNS treatment decreased the CDDP or CDDP plus HIF-1α-knockdown-induced elevation of apoptosis and apoptosis-associated protein expressions. These findings demonstrate that PNS reduces CAKI through increasing HIF-1α to inhibit mitochondrial apoptosis pathway. Hence, we suggest PNS as a protective and therapeutic new drug for CDDP treatment of cancers, which might have significant meaning of further research and application potential.

Keywords:  Cisplatin-induced acute kidney injury; HIF-1α-siRNA; Mitochondrial apoptosis pathway; Panax notoginseng saponins

DOI:  https://doi.org/10.1016/j.biopha.2021.111965
Neoplasma. 2021 Aug 11. pii: 210308N296. [Epub ahead of print]

Hypoxia facilitates the proliferation of colorectal cancer cells by inducing cancer-associated fibroblast-derived IL6.

Ying Xu, Rong Kuai, Yi-Min Chu, Lu Zhou, Hai-Qin Zhang, Ji Li.

Colorectal cancer (CRC) is the most common malignancy worldwide, and its underlying molecular mechanisms remain largely unexplored. Accumulating evidences indicate cancer-associated fibroblasts (CAFs), abundant stromal cell population in the tumor microenvironment, play a key role in tumor development. Herein, we have successfully isolated CAFs and paired normal fibroblasts (NFs) from colorectal cancer tissues (n = 10). By using a multiplex cytokine profiling assay, we have identified IL-6 as a major cytokine released by CAFs. Co-culturing of CAFs with CRC cell lines HCT116 or SW480 increases IL-6 release, and the secretion by CAFs can be further enhanced under hypoxia. By using the CCK-8 assay, we have found that HCT116 or SW480 cells treated with culture medium from CAFs, IL-6, or hypoxia showed a significant cell growth compared to control cells (P < 0.01). Mechanistically, we have found hypoxia could enhance the effect of the IL-6/STAT3 signaling on CRC cells, in part, through HIF-1a targeting PKM2. In conclusion, our data clearly proposes the interconnected mechanisms for constitutive activation of STAT3 signal by CAFs-derived IL-6 under hypoxia in colorectal cancer. The pharmacological inhibition of STAT3, PKM2, or HIF-1α can significantly reduce the oncogenic effect of IL-6, providing a potential therapeutic target for CRC patients.

DOI: https://doi.org/10.4149/neo_2021_210308N296
Brain Struct Funct. 2021 Sep;226(7): 2169-2180

Effects of detraining on preconditioning exercise-induced neuroprotective potential after ischemic stroke in rats.

Shotaro Otsuka, Harutoshi Sakakima, Akira Tani, Kazuki Nakanishi, Seiya Takada, Kosuke Norimatsu, Hiroshi Maejima, Ikuro Maruyama.

  Preconditioning exercise prior to stroke exerts neuroprotection, which is an endogenous strategy that leads the brain cells to express several intrinsic factors and inhibits their apoptosis. However, it is unclear how long these benefits last after exercise cessation. The aim of this study was to investigate the effects of detraining on preconditioning exercise-induced neuroprotective potential after stroke. Rats were trained using a treadmill for aerobic exercise 5 days each week for 3 weeks, and their neuroprotective effects were examined until 3 weeks after exercise cessation. Stroke was induced by 60 min of left middle cerebral artery occlusion at 3 days, 1, 2, and 3 weeks after exercise cessation. Infarct volume, neurological deficits, sensorimotor function, expression levels of brain-derived neurotrophic factor (BDNF), hypoxia-induced factor-1α (HIF-1α), glial fibrillary acidic protein (GFAP), and P2X7 receptors, and apoptosis activity were examined using immunohistochemical and western blot analyses. Preconditioning exercise significantly reduced infarct volume and ameliorated sensorimotor function after stroke, and its beneficial effects were observed until 2 weeks after exercise cessation. The expression level of BDNF in the ischemic brain was significantly upregulated at 3 days after exercise cessation; however, the expression levels of HIF-1α, GFAP, and P2X7 receptor were significantly increased until 2 weeks after exercise cessation; thereby, significant anti-apoptotic effects were lost at 3 weeks of detraining. Our findings suggest that preconditioning exercise-induced neuroprotective potential may be lost shortly after exercise cessation. Neuroprotection through intrinsic protective factors, such as BDNF and HIF-1α, may provide different neuroprotective mechanisms in a time-dependent manner during detraining.

Keywords:  Apoptotic activity; BDNF; Exercise cessation; HIF-1α; Neuroprotection; Preconditioning exercise

DOI:  https://doi.org/10.1007/s00429-021-02317-5
Cell Cycle. 2021 Aug 12. 1-16

NAD+ metabolism controls growth inhibition by HIF1 in normoxia and determines differential sensitivity of normal and cancer cells.

Michal W Luczak, Casey Krawic, Anatoly Zhitkovich.

  The hypoxia-induced transcription factor HIF1 inhibits cell growth in normoxia through poorly understood mechanisms. A constitutive upregulation of hypoxia response is associated with increased malignancy, indicating a loss of antiproliferative effects of HIF1 in cancer cells. To understand these differences, we examined a control of cell cycle in primary human cells with activated hypoxia response in normoxia. Activated HIF1 caused a global slowdown of cell cycle progression through G1, S and G2 phases leading to the loss of mitotic cells. Cell cycle inhibition required a prolonged HIF1 activation and was not associated with upregulation of p53 or the CDK inhibitors p16, p21 or p27. Growth inhibition by HIF1 was independent of its Asn803 hydroxylation or the presence of HIF2. Antiproliferative effects of hypoxia response were alleviated by inhibition of lactate dehydrogenase and more effectively, by boosting cellular production of NAD+, which was decreased by HIF1 activation. In comparison to normal cells, various cancer lines showed several fold-higher expression of NAMPT which is a rate-limiting enzyme in the main biosynthetic pathway for NAD+. Inhibition of NAMPT activity in overexpressor cancer cells sensitized them to antigrowth effects of HIF1. Thus, metabolic changes in cancer cells, such as enhanced NAD+ production, create resistance to growth-inhibitory activity of HIF1 permitting manifestation of its tumor-promoting properties.AbbreviationsDMOG: dimethyloxalylglycine, DM-NOFD: dimethyl N-oxalyl-D-phenylalanine, NMN: β-nicotinamide mononucleotide.

Keywords:  HIF1A; NAD+; NAMPT; cell cycle; hypoxia

DOI:  https://doi.org/10.1080/15384101.2021.1959988
World J Gastroenterol. 2021 Jul 28. 27(28): 4582-4602

Modulation of cell physiology under hypoxia in pancreatic cancer.

Matias Estaras, Antonio Gonzalez.

  In solid tumors, the development of vasculature is, to some extent, slower than the proliferation of the different types of cells that form the tissue, both cancer and stroma cells. As a consequence, the oxygen availability is compromised and the tissue evolves toward a condition of hypoxia. The presence of hypoxia is variable depending on where the cells are localized, being less extreme at the periphery of the tumor and more severe in areas located deep within the tumor mass. Surprisingly, the cells do not die. Intracellular pathways that are critical for cell fate such as endoplasmic reticulum stress, apoptosis, autophagy, and others are all involved in cellular responses to the low oxygen availability and are orchestrated by hypoxia-inducible factor. Oxidative stress and inflammation are critical conditions that develop under hypoxia. Together with changes in cellular bioenergetics, all contribute to cell survival. Moreover, cell-to-cell interaction is established within the tumor such that cancer cells and the microenvironment maintain a bidirectional communication. Additionally, the release of extracellular vesicles, or exosomes, represents short and long loops that can convey important information regarding invasion and metastasis. As a result, the tumor grows and its malignancy increases. Currently, one of the most lethal tumors is pancreatic cancer. This paper reviews the most recent advances in the knowledge of how cells grow in a pancreatic tumor by adapting to hypoxia. Unmasking the physiological processes that help the tumor increase its size and their regulation will be of major relevance for the treatment of this deadly tumor.

Keywords:  Cancer; Cell survival; Hypoxia; Pancreas; Proliferation; Tumor

DOI:  https://doi.org/10.3748/wjg.v27.i28.4582
Curr Mol Pharmacol. 2021 Aug 11.

Hypoxia boosts aerobic glycolysis of carcinoma：a complex process for tumor development.

Xiuqin Zheng, Hui Fan, Yang Liu, Zhonghong Wei, Xiaoman Li, Aiyun Wang, Wenxing Chen, Yin Lu.

  Hypoxia, a common feature in malignant tumors, is mainly caused by insufficient oxygen supply. Hypoxia is closely related to cancer development, affecting cancer invasion and metastasis, energy metabolism and other pathological processes, and is not conducive to cancer treatment and prognosis. Tumor cells exacerbate metabolic abnormalities to adapt to the hypoxic microenvironment, especially to enhance aerobic glycolysis. Glycolysis leads to an acidic microenvironment in cancer tissues, enhancing cancer metastasis, deterioration and drug resistance. Therefore, hypoxia is a therapeutic target that cannot be ignored in cancer treatment. The adaptation of tumor cells to hypoxia is mainly regulated by hypoxia inducible factors (HIFs), and the stability of HIFs is improved under hypoxic conditions. HIFs can promote the glycolysis of tumors by regulating glycolytic enzymes, transporters, and participates in regulating the TCA (tricarboxylic acid) cycle. In addition, HIFs indirectly affect glycolysis through its interaction with non-coding RNAs. Therefore, targeting hypoxia and HIFs are important tumor therapies.

Keywords:  Glycolysis; Hypoxia; Hypoxia-inducible factors; Non-coding RNA; Tumor microenvironment

DOI:  https://doi.org/10.2174/1874467214666210811145752
Oncol Lett. 2021 Sep;22(3): 639

Triple therapy with osimertinib, bevacizumab and cetuximab in EGFR-mutant lung cancer with HIF-1α/TGF-α expression.

Kazuya Nishii, Kadoaki Ohashi, Hiromi Watanabe, Go Makimoto, Takamasa Nakasuka, Hisao Higo, Kiichiro Ninomiya, Yuka Kato, Toshio Kubo, Kammei Rai, Eiki Ichihara, Katsuyuki Hotta, Masahiro Tabata, Yoshinobu Maeda, Katsuyuki Kiura.

  Osimertinib, a third generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, is the standard treatment for patients with lung cancer harboring EGFR T790M; however, acquired resistance is inevitable due to genetic and epigenetic changes in cancer cells. In addition, a recent randomized clinical trial revealed that the combination of osimertinib and bevacizumab failed to exhibit superior progression-free survival compared with osimertinib alone. The present study aimed to investigate the effect of triple therapy with osimertinib, bevacizumab and cetuximab in xenograft tumors with different initial tumor volumes (conventional model, 200 mm3 and large model, 500 mm3). The results demonstrated that osimertinib significantly inhibited tumor growth in both the conventional and large models; however, maximum tumor regression was attenuated in the large model in which hypoxia-inducible factor-1α (HIF-1α) and transforming growth factor-α (TGF-α) expression levels increased. Although the combination of osimertinib and bevacizumab exerted a greater inhibitory effect on tumor growth compared with osimertinib in the conventional model, the effect of this combination therapy was attenuated in the large model. TGF-α attenuated sensitivity to osimertinib in vitro; however, this negative effect was counteracted by the combination of osimertinib and cetuximab, but not osimertinib and bevacizumab. In the large xenograft tumor model, the triple therapy induced the greatest inhibitory effect on tumor growth compared with osimertinib alone and its combination with bevacizumab. Clinical trials of the triple therapy are required for patients with lung cancer with EGFR mutations and HIF-1α/TGF-α.

Keywords:  bevacizumab; cetuximab; epidermal growth factor receptor; hypoxia-inducible factor-1α; osimertinib; transforming growth factor-α

DOI:  https://doi.org/10.3892/ol.2021.12900
Front Cell Dev Biol. 2021 ;9 679637

Autophagy-Related LC3 Accumulation Interacted Directly With LIR Containing RIPK1 and RIPK3, Stimulating Necroptosis in Hypoxic Cardiomyocytes.

Yao Huang, Yanhai Feng, Lin Cui, Lei Yang, Qiong Zhang, Junhui Zhang, Xupin Jiang, Xingyue Zhang, Yanling Lv, Jie-Zhi Jia, Dong-Xia Zhang, Yue-Sheng Huang.

  The exact relationships and detailed mechanisms between autophagy and necroptosis remain obscure. Here, we demonstrated the link between accumulated autophagosome and necroptosis by intervening with autophagic flux. We first confirmed that the LC3 interacting region (LIR) domain is present in the protein sequences of RIPK1 and RIPK3. Mutual effects among LC3, RIPK1, and RIPK3 have been identified in myocardium and cardiomyocytes. Direct LC3-RIPK1 and LC3-RIPK3 interactions were confirmed by pull-down assays, and their interactions were deleted after LIR domain mutation. Moreover, after disrupting autophagic flux under normoxia with bafilomycin A1 treatment, or with LC3 or ATG5 overexpression adenovirus, RIPK1, RIPK3, p-RIPK3, and p-MLKL levels increased, suggesting necroptosis activation. Severe disruptions in autophagic flux were observed under hypoxia and bafilomycin A1 co-treated cardiomyocytes and myocardium and led to more significant activation of necroptosis. Conversely, after alleviating hypoxia-induced autophagic flux impairment with LC3 or ATG5 knockdown adenovirus, the effects of hypoxia on RIPK1 and RIPK3 levels were reduced, which resulted in decreased p-RIPK3 and p-MLKL. Furthermore, necroptosis was inhibited by siRNAs against RIPK1 and RIPK3 under hypoxia or normoxia. Based on our results, LIR domain mediated LC3-RIPK1 and LC3-RIPK3 interaction. Besides, autophagosome accumulation under hypoxia lead to necrosome formation and, in turn, necroptosis, while when autophagic flux was uninterrupted, RIPK1 and RIPK3 were cleared through an autophagy-related pathway which inhibited necroptosis. These findings provide novel insights for the role of LC3 in regulating cardiomyocyte necroptosis, indicating its therapeutic potential in the prevention and treatment of hypoxic myocardial injury and other hypoxia-related diseases.

Keywords:  LC3; autophagosome; autophagy; myocardial hypoxia; necroptosis

DOI:  https://doi.org/10.3389/fcell.2021.679637
Oncoimmunology. 2021 ;10(1): 1950953

Hypoxia increases melanoma-associated fibroblasts immunosuppressive potential and inhibitory effect on T cell-mediated cytotoxicity.

Linda Ziani, Stéphanie Buart, Salem Chouaib, Jerome Thiery.

  Cancer-associated fibroblasts (CAFs) and hypoxia are central players in the complex process of tumor cell-stroma interaction and are involved in the alteration of the anti-tumor immune response by impacting both cancer and immune cell populations. However, even if their independent immunomodulatory properties are now well documented, whether the interaction between these two components of the tumor microenvironment can affect CAFs ability to alter the anti-tumor immune response is still poorly defined. In this study, we provide evidence that hypoxia increases melanoma-associated fibroblasts expression and/or secretion of several immunosuppressive factors (including TGF-β, IL6, IL10, VEGF and PD-L1). Moreover, we demonstrate that hypoxic CAF secretome exerts a more profound effect on T cell-mediated cytotoxicity than its normoxic counterpart. Together, our data suggest that the crosstalk between hypoxia and CAFs is probably an important determinant in the complex immunosuppressive tumor microenvironment.

Keywords:  CTL; Cancer-associated fibroblasts; hypoxia; immunosuppression

DOI:  https://doi.org/10.1080/2162402X.2021.1950953
J Biosci Bioeng. 2021 Aug 04. pii: S1389-1723(21)00174-2. [Epub ahead of print]

Hypoxia-responsive expression of vascular endothelial growth factor for induction of angiogenesis in artificial three-dimensional tissues.

Shinya Masumoto, Akihiko Ono, Akira Ito, Yoshinori Kawabe, Masamichi Kamihira.

  Constructing three-dimensional (3D) tissues is an important process to improve cellular functions in tissue engineering. When transplanting artificially constructed tissues, a poor vascular network restricts oxygen and nutrient supplies to the tissue cells, which leads to cell death and reduced rates of tissue engraftment. Therefore, it is necessary to develop a system that builds a vascular network within 3D tissues. Here, we developed a hypoxia-responsive gene expression system for production of an angiogenic factor, vascular endothelial growth factor (VEGF), to improve hypoxia and nutrition deficiencies inside artificial 3D tissues. We demonstrated that cells into which the hypoxia-responsive VEGF gene expression system had been introduced autonomously controlled VEGF expression in a hypoxic stress-dependent manner. Next, we confirmed that VEGF expression within a 3D cell sheet was induced in response to a hypoxic environment in vitro. The genetically modified cell sheet was subcutaneously transplanted into mice to evaluate the feasibility of the hypoxia-responsive VEGF gene expression system in vivo. The results suggest that the hypoxia-responsive VEGF gene expression system is promising to prepare artificial 3D tissues in regenerative medicine.

Keywords:  Angiogenesis; Gene expression system; Hypoxia; Oxygen-dependent degradation domain; RTP801 promoter; Three-dimensional culture; Transplantation; Vascular endothelial growth factor

DOI:  https://doi.org/10.1016/j.jbiosc.2021.06.010
Bioengineered. 2021 Dec;12(1): 5028-5044

Long non-coding RNA VCAN-AS1 promotes the malignant behaviors of breast cancer by regulating the miR-106a-5p-mediated STAT3/HIF-1α pathway.

Peng Du, Kaifeng Luo, Guoyong Li, Jisheng Zhu, Qi Xiao, Yong Li, Xingjian Zhang.

  An accumulating number of studies have found that long noncoding RNAs (lncRNAs) participate in breast cancer (BC) development. LncRNA VCAN-AS1, a novel lncRNA, has been confirmed to regulate the progression of gastric cancer, while its role in BC is elusive. Here, our results illustrate that VCAN-AS1 is overexpressed in BC tissues and cells, while miR-106a-5p was downregulated and negatively correlated with VCAN-AS1. In addition, high VCAN-AS1 expression and low miR-106a-5p expression were closely correlated with poor overall survival in BC patients. Functional experiments confirmed that VCAN-AS1 overexpression notably accelerated BC cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) and enhanced tumor cell growth while also suppressing cell apoptosis. However, overexpression of miR-106a-5p had the opposite effects. In addition, rescue experiments confirmed that overexpression of VCAN-AS1 inhibited the tumor-suppressive effects mediated by miR-106a-5p. Mechanistically, through bioinformatics analysis, we found that VCAN-AS1 functions as a competitive endogenous RNA (ceRNA) of miR-106a-5p, which targets the 3' untranslated region (UTR) of signal transducer and activator of transcription 3 (STAT3). Further experiments indicated that miR-106a-5p downregulated the STAT3/hypoxia-inducible factor-1alpha (HIF-1α) pathway, while activating the STAT3 pathway reversed miR-106a-5p-mediated antitumor effects. Collectively, our data suggest that VCAN-AS1 is upregulated in breast cancer and promotes its progression by regulating the miR-106a-5p-mediated STAT3/HIF-1α pathway. This study provides a new target for BC therapy.

Keywords:  Breast cancer; HIF-1α; STAT3; VCAN-AS1; ceRNA; miR-106a-5p

DOI:  https://doi.org/10.1080/21655979.2021.1960774
Acta Oncol. 2021 Aug 11. 1-10

Evaluation of 18F-EF5 for detection of hypoxia in localized adenocarcinoma of the prostate.

Brennan J Wadsworth, Lisa R Decotret, Carlos Villamil, Donald Yapp, Don Wilson, Francois Benard, Michael McKenzie, Kevin L Bennewith.

   BACKGROUND: A common feature of solid tumours that are resistant to therapy is the presence of regions with low oxygen content (i.e., hypoxia). Oxygen electrode studies suggest that localized prostate adenocarcinoma is commonly hypoxic, although conflicting data have been reported between immunohistochemical detection of hypoxia-induced proteins in biopsy specimens and positron emission tomography (PET) imaging of 18F-labeled hypoxia reporters. Although the 2-nitroimidazole 18F-EF5 is well-established to label hypoxic tumour cells in pre-clinical tumour models and clinical trials of multiple primary tumour sites, it has yet to be tested in prostate cancer. The purpose of this study was to evaluate the feasibility of using 18F-EF5 to detect hypoxia in clinical prostate tumours.
MATERIAL AND METHODS: Patients with localized adenocarcinoma of the prostate were recruited for pre-treatment 18F-EF5 PET scans. Immunohistochemistry was conducted on diagnostic biopsies to assess the expression of glucose transporter 1 (GLUT1), osteopontin (OPN), and carbonic anhydrase IX (CAIX). Immunoreactivity scores of staining intensity and frequency were used to indicate the presence of tumour hypoxia.
RESULTS: We found low tumour-to-muscle ratios of 18F-EF5 uptake that were not consistent with tumour hypoxia, causing early termination of the study. However, we observed GLUT1 and OPN expression in all prostate tumour biopsies, indicating the presence of hypoxia in all tumours.
CONCLUSION: Our data do not support the use of 18F-EF5 PET to detect hypoxia in prostate adenocarcinoma, and suggest the use of immunohistochemistry to quantify expression of the hypoxia-inducible proteins GLUT1 and OPN as indications of prostate tumour hypoxia.

Keywords:  EF5; Hypoxia; carbonic anhydrase-9; glucose transporter-1; osteopontin; positron emission tomography

DOI:  https://doi.org/10.1080/0284186X.2021.1959636
Stem Cell Res Ther. 2021 Aug 09. 12(1): 448

Hypoxia preconditioned bone marrow-derived mesenchymal stromal/stem cells enhance myoblast fusion and skeletal muscle regeneration.

Karolina Archacka, Iwona Grabowska, Bartosz Mierzejewski, Joanna Graffstein, Alicja Górzyńska, Marta Krawczyk, Anna M Różycka, Ilona Kalaszczyńska, Gabriela Muras, Władysława Stremińska, Katarzyna Jańczyk-Ilach, Piotr Walczak, Mirosław Janowski, Maria A Ciemerych, Edyta Brzoska.

   BACKGROUND: The skeletal muscle reconstruction occurs thanks to unipotent stem cells, i.e., satellite cells. The satellite cells remain quiescent and localized between myofiber sarcolemma and basal lamina. They are activated in response to muscle injury, proliferate, differentiate into myoblasts, and recreate myofibers. The stem and progenitor cells support skeletal muscle regeneration, which could be disturbed by extensive damage, sarcopenia, cachexia, or genetic diseases like dystrophy. Many lines of evidence showed that the level of oxygen regulates the course of cell proliferation and differentiation.
METHODS: In the present study, we analyzed hypoxia impact on human and pig bone marrow-derived mesenchymal stromal cell (MSC) and mouse myoblast proliferation, differentiation, and fusion. Moreover, the influence of the transplantation of human bone marrow-derived MSCs cultured under hypoxic conditions on skeletal muscle regeneration was studied.
RESULTS: We showed that bone marrow-derived MSCs increased VEGF expression and improved myogenesis under hypoxic conditions in vitro. Transplantation of hypoxia preconditioned bone marrow-derived MSCs into injured muscles resulted in the improved cell engraftment and formation of new vessels.
CONCLUSIONS: We suggested that SDF-1 and VEGF secreted by hypoxia preconditioned bone marrow-derived MSCs played an essential role in cell engraftment and angiogenesis. Importantly, hypoxia preconditioned bone marrow-derived MSCs more efficiently engrafted injured muscles; however, they did not undergo myogenic differentiation.

Keywords:  BM-MSC; Fusion; Hypoxia; Migration; Myogenic differentiation; Normoxia

DOI:  https://doi.org/10.1186/s13287-021-02530-3
Zhonghua Yi Xue Yi Chuan Xue Za Zhi. 2021 Aug 10. 38(8): 812-817

[Silencing LncRNA SNHG7 alleviates hypoxia/reoxygenation-induced cardiomyocyte damage by regulating the expression of miR-181b-5p].

Zhen Liu, Weidong Jin, Minglei Han, Jiajia Cui, Yonglan Hou, Guangcui Xu.

OBJECTIVE: To study the effect of silencing LncRNA SNHG7 on hypoxia/reoxygenation (H/R)-induced cardiomyocyte injury and its targeted regulation on miR-181b-5p.
METHODS: Rat cardiomyocytes H9c2 were cultured in vitro and randomly divided into control group, H/R group, H/R + si-NC group, H/R + si-SNHG7 group, H/R + si-SNHG7 + anti-miR-NC group and H/R + si-SNHG7 + anti-miR-181b-5p group. The content of lactate dehydrogenase (LDH), malondialedhyde (MDA) and the activity of superoxide dismutase (SOD) were detected. Flow cytometry was carried out to detect the rate of apoptosis. qRT-PCR was used to detect the expression of SNHG7 and miR-181b-5p. Dual luciferase report experiment was used to verify the targeting relationship between SNHG7 and miR-181b-5p. Western blotting was used to detect the expression of Bax and Bcl-2.
RESULTS: Compared with the control group, the H/R group showed significantly increased SNHG7 expression in cardiomyocytes, reduced miR-181b-5p expression, higher levels of LDH and MDA, reduced activity of SOD, increased cell apoptosis rate, higher level of Bax protein, and reduced level of Bcl-2 protein (all P< 0.05). Compared with the H/R and H/R + si-NC groups, the H/R + si-SNHG7 group had significantly reduced level of LDH and MDA, increased activity of SOD, reduced apoptosis rate, reduced level of Bax protein, increased level of Bcl-2 protein (all P< 0.05). The dual luciferase report experiment confirmed that SNHG7 could target miR-181b-5p. Interference with the expression of miR-181b-5p could reduce the effect of silencing SNHG7 on H/R-induced cardiomyocyte oxidative stress and apoptosis.
CONCLUSION: Silencing SNHG7 may inhibit H/R-induced cardiomyocyte oxidative stress and apoptosis by up-regulating the expression of miR-181b-5p, thereby exerting a protective effect on cardiomyocytes.

DOI: https://doi.org/10.3760/cma.j.cn511374-20200520-0360