Airway Basal Cells Mediate Hypoxia-Induced EMT by Increasing Ribosome Biogenesis

Excessive secretion of airway mucus and fluid accumulation are the common features of many respiratory diseases, which, in turn, induce cell hypoxia in the airway epithelium, resulting in epithelial–mesenchymal transition (EMT) and ultimately fibrosis. However, the mechanisms of EMT induced by hypoxia in the airway are currently unclear. To mimic the status of edematous fluid retention in the airway, we cultured primary mouse tracheal epithelial cells (MTECs) in a liquid–liquid interface (LLI) mode after full differentiation in a classic air–liquid interface (ALI) culture system. The cell hypoxia was verified by the physical characteristics and lactate production in cultured medium as well as HIF expression in MTECs cultured by LLI mode. EMT was evidenced and mainly mediated by basal cells, supported by flow cytometry and immunofluorescence assay. The differently expressed genes of basal and other airway epithelial cells were found to be enriched in the ribosome by our analysis of an MTEC single-cell RNA sequencing data set and Myc, the global regulator of ribosome biogenesis was identified to be highly expressed in basal cells. We next separated basal cells from bulk MTECs by flow cytometry, and the real-time PCR results showed that ribosome biogenesis was significantly upregulated in basal cells, whereas the inhibition of ribosome biogenesis alleviated the phosphorylation of the mammalian target of rapamycin/AKT and abrogated hypoxia-induced EMT in MTECs. Collectively, these observations strongly suggest that basal cells in the airway epithelium may mediate the process of hypoxia-induced EMT, partly through enhancing ribosome biogenesis.

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

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

MiR-182 Promotes Ischemia/Reperfusion-Induced Acute Kidney Injury in Rat by Targeting FoxO3

<b><i>Background:</i></b> Renal ischemia/reperfusion (I/R) injury (RIRI) is the main cause of acute kidney injury (AKI) in patients. We investigated the role of miR-182 after renal ischemia/reperfusion (I/R) in rat to characterize the microRNA (miRNA) network activated during development and recovery from RIRI. <b><i>Methods and Results:</i></b> 12 h after lethal (45 min) renal ischemia, AKI was verified by renal histology (tubular necrosis and regeneration), blood urea nitrogen level, and renal mRNA expression in Wistar rats. We found that miR-182 markedly increased after renal I/R. In cell hypoxia/reoxygenation model, we found similar upregulation of miR-182. In function gain/loss assay, we confirmed an impaired effect of miR-182 and identified Forkhead box O3 (FoxO3) as a direct downstream target of it. By using miR-182 antagomir, the I/R injury was markedly ameliorated. <b><i>Conclusions:</i></b> Our results demonstrate that miR-182 promotes cell apoptosis and I/R injury through directly binding to FoxO3. The present study will provide potential therapeutic targets for renal I/R-induced AKI, and open a new avenue for AKI treatment by manipulating miRNAs levels.

Will Your Breast Cancer Patient’s Mortality Go Up in Smoke?

Dedicated smokers who receive breast radiation may pay an unexpected price[1]in both recurrence risk and in mortality. Smoking during radiation therapy (RT) noticeably increases (and accelerates) the recurrence risk, but it also increases long-term risks of lung and heart mortality. The recurrence risk probably derives from (temporary) smoking - caused hypoxia. On the other hand, concurrent RT and smoking produces synergistic and permanent heart and lung damage. Tumor cell hypoxia can be exogenous (via smoking) or endogenous (inadequate capillary perfusion) or possibly even environmental (at high altitudes). However it occurs, though, it is a major contributor to treatment failure. Techniques for addressing hypoxia - both currently in the clinic, and on the technological horizon - are briefly reviewed here. These include photoacoustics, FLASH radiotherapy, and Cherenkov - Excited Luminescence Imaging (CELI).

Generalizable synthesis of bioresponsive near-infrared fluorescent probes: sulfonated heptamethine cyanine prototype for imaging cell hypoxia

A new synthetic method produces a bioresponsive near-infrared molecular probe that undergoes “turn-on” fluorescence for microscopic imaging of hypoxia.

Oxidative stress in animals: role in oncogenesis from pathomorphologist view

Oxidative stress is a pathological accumulation of free radicals that contribute to the launch of intracellular damaging action mechanisms. Free radical is an atom possessing free or missing electron, and seeking to restore the lost electron, taking it from other molecules ― as a result a new free radical is formed. The mechanism is chain reaction-based. Hypoxia acts as an additional stimulus to the appearance of oxygen free radicals. Cell hypoxia develops following any type of cell damage: mechanical, bacteriological, chemical, etc. Cell hypoxia inevitably leads to the development of an inflammatory reaction, which is followed by the formation of oxygen free radicals and, as a result, by oxidative stress development.

Salvia miltiorrhiza alleviates hypoxia-induced nerve injury associated with Ngb/Akt intracellular signaling pathway

Background: Salvia miltiorrhiza (Danshen), a traditional Chinese herbal medicine, can effectively improve the high-altitude adverse reactions of high-altitude patients. While, the mechanism of how they exert neuroprotective effect to intervene the hypoxic at high altitudes is still not well understood.Methods: The study established high altitude hypoxia mouse model and CoCl2 -induced PC12 cell hypoxia model , the protective effects of S. miltiorrhiza radix extract (SE), Tanshinone IIA (Tan IIA) and salvianic acid A sodium (SAS) on hypoxia model were studied in vitro and in vivo.Results: The results showed that SE, TanⅡA, and SAS are able to improve biochemical level in high altitude hypoxia mouse model, increase in Ca2+ concentration, and decrease in MMP, inhibit apoptosis in CoCl2 -induced PC12 cell hypoxia model by activating Akt signaling pathway, protecting neurons, thus improving the oxygen carrying capacity of brain tissue.Conclusion: This study confirms the efficacy of SE, Tan Ⅱ A, and SAS with respect to therapeutic treatment of hypoxia, shown that S. miltiorrhiza and its active monomers can protect neurons by activating Ngb/Akt intracellular signaling pathway, and attenuate cerebral anoxia and neuronal damage, subsequently nerve injury caused by hypoxia at high altitude. Providing important information for the clinical treatment of nerve injury caused by hypoxia at high altitude.

lncRNA Mediated Hijacking of T-cell Hypoxia Response Pathway by Mycobacterium tuberculosis Predicts Latent to Active Progression in Humans

Cytosolic functions of Long non-coding RNAs including mRNA translation masking and sponging are major regulators of biological pathways. Formation of T cell-bounded hypoxic granuloma is a host immune defence for containing infected Mtb-macrophages. Our study exploits the mechanistic pathway of Mtb-induced HIF1A silencing by the antisense lncRNA-HIF1A-AS2 in T cells. Computational analysis of in-vitro T-cell stimulation assays in progressors (n=119) versus non-progressor (n=221) tuberculosis patients revealed the role of lncRNA mediated disruption of hypoxia adaptation pathways in progressors. We found 291 upregulated and 227 downregulated DE lncRNAs that were correlated at mRNA level with HIF1A and HILPDA which are major players in hypoxia response. We also report novel lncRNA-AC010655 (AC010655.4 and AC010655.2) in cis with HILPDA, both of which contain binding sites for the BARX2 transcription factor, thus indicating a mechanistic role. Detailed comparison of infection with antigenic stimulation showed a non-random enrichment of lncRNAs in the cytoplasmic fraction of the cell in TB progressors. The lack of this pattern in non-progressors replicates indicates the hijacking of the lncRNA dynamics by Mtb. The in-vitro manifestation of this response in the absence of granuloma indicates pre-programmed host-pathogen interaction between T-cells and Mtb regulated through lncRNAs, thus tipping this balance towards progression or containment of Mtb. Finally, we trained multiple machine learning classifiers for reliable prediction of latent to the active progression of patients, yielding a model to guide aggressive treatment.