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Microbiology Spectrum Jun 2024is a microaerophilic Gram-negative bacterium that resides in the human stomach and is classified as a class I carcinogen for gastric cancer. Numerous studies have...
is a microaerophilic Gram-negative bacterium that resides in the human stomach and is classified as a class I carcinogen for gastric cancer. Numerous studies have demonstrated that infection plays a role in regulating the function of host cells, thereby contributing to the malignant transformation of these cells. However, infection is a chronic process, and short-term cellular experiments may not provide a comprehensive understanding of the situation, especially when considering the lower oxygen levels in the human stomach. In this study, we aimed to investigate the mechanisms underlying gastric cell dysfunction after prolonged exposure to under hypoxic conditions. We conducted a co-culture experiment using the gastric cell line GES-1 and for 30 generations under intermittent hypoxic conditions. By closely monitoring cell proliferation, migration, invasion, autophagy, and apoptosis, we revealed that sustained stimulation under hypoxic conditions significantly influences the function of GES-1 cells. This stimulation induces epithelial-mesenchymal transition and contributes to the propensity for malignant transformation of gastric cells. To confirm the results, we conducted an experiment involving Mongolian gerbils infected with for 85 weeks. All the results strongly suggest that the Nod1 receptor signaling pathway plays a crucial role in -related apoptosis and autophagy. In summary, continuous stimulation by affects the functioning of gastric cells through the Nod1 receptor signaling pathway, increasing the likelihood of cell carcinogenesis. The presence of hypoxic conditions further exacerbates this process.IMPORTANCEDeciphering the collaborative effects of infection on gastric epithelial cell function is key to unraveling the development mechanisms of gastric cancer. Prior research has solely examined the outcomes of short-term stimulation on gastric epithelial cells under aerobic conditions, neglecting the bacterium's nature as a microaerophilic organism that leads to cancer following prolonged stomach colonization. This study mimics a more genuine infection scenario by repeatedly exposing gastric epithelial cells to under hypoxic conditions for up to 30 generations. The results show that chronic exposure to in hypoxia substantially increases cell migration, invasion, and epithelial-mesenchymal transition, while suppressing autophagy and apoptosis. This highlights the significance of hypoxic conditions in intensifying the carcinogenic impact of infection. By accurately replicating the gastric environment, this study enhances our comprehension of 's pathogenic mechanisms in gastric cancer.
PubMed: 38916312
DOI: 10.1128/spectrum.00311-24 -
Frontiers in Physiology 2024The complex and dynamic interaction between cellular energy control and gene expression modulation is shown by the intersection between mitochondrial metabolism and... (Review)
Review
The complex and dynamic interaction between cellular energy control and gene expression modulation is shown by the intersection between mitochondrial metabolism and epigenetics in hypoxic environments. Poor oxygen delivery to tissues, or hypoxia, is a basic physiological stressor that sets off a series of reactions in cells to adapt and endure oxygen-starved environments. Often called the "powerhouse of the cell," mitochondria are essential to cellular metabolism, especially regarding producing energy through oxidative phosphorylation. The cellular response to hypoxia entails a change in mitochondrial metabolism to improve survival, including epigenetic modifications that control gene expression without altering the underlying genome. By altering the expression of genes involved in angiogenesis, cell survival, and metabolism, these epigenetic modifications help cells adapt to hypoxia. The sophisticated interplay between mitochondrial metabolism and epigenetics in hypoxia is highlighted by several important points, which have been summarized in the current article. Deciphering the relationship between mitochondrial metabolism and epigenetics during hypoxia is essential to understanding the molecular processes that regulate cellular adaptation to reduced oxygen concentrations.
PubMed: 38915781
DOI: 10.3389/fphys.2024.1393232 -
Frontiers in Physiology 2024Efficient distribution of oxygen (O) to the tissues in mammals depends on the evolved ability of red blood cell (RBC) hemoglobin (Hb) to sense not only O levels, but... (Review)
Review
Efficient distribution of oxygen (O) to the tissues in mammals depends on the evolved ability of red blood cell (RBC) hemoglobin (Hb) to sense not only O levels, but metabolic cues such as pH, PCO, and organic phosphates, and then dispense or take up oxygen accordingly. O delivery is the product of not only oxygen release from RBCs, but also blood flow, which itself is also governed by vasoactive molecular mediators exported by RBCs. These vascular signals, including ATP and S-nitrosothiols (SNOs) are produced and exported as a function of the oxygen and metabolic milieu, and then fine-tune peripheral metabolism through context-sensitive vasoregulation. Emerging and repurposed RBC-oriented therapeutics can modulate either or both of these allosteric and vasoregulatory activities, with a single molecule or other intervention influencing both arms of O transport in some cases. For example, organic phosphate repletion of stored RBCs boosts the negative allosteric effector 2,3 biphosphoglycerate (BPG) as well as the anti-adhesive molecule ATP. In sickle cell disease, aromatic aldehydes such as voxelotor can disfavor sickling by increasing O affinity, and in newer generations, these molecules have been coupled to vasoactive nitric oxide (NO)-releasing adducts. Activation of RBC pyruvate kinase also promotes a left shift in oxygen binding by consuming and lowering BPG, while increasing the ATP available for cell health and export on demand. Further translational and clinical investigation of these novel allosteric and/or vasoregulatory approaches to modulating O transport are expected to yield new insights and improve the ability to correct or compensate for anemia and other O delivery deficits.
PubMed: 38915775
DOI: 10.3389/fphys.2024.1394650 -
BioRxiv : the Preprint Server For... Jun 2024Terminal deoxynucleotidyl transferase (TdT) is a unique DNA polymerase capable of template-independent extension of DNA with random nucleotides. TdT's DNA synthesis...
Terminal deoxynucleotidyl transferase (TdT) is a unique DNA polymerase capable of template-independent extension of DNA with random nucleotides. TdT's DNA synthesis ability has found utility in DNA recording, DNA data storage, oligonucleotide synthesis, and nucleic acid labeling, but TdT's intrinsic nucleotide biases limit its versatility in such applications. Here, we describe a multiplexed assay for profiling and engineering the bias and overall activity of TdT variants in high throughput. In our assay, a library of TdTs is encoded next to a CRISPR-Cas9 target site in HEK293T cells. Upon transfection of Cas9 and sgRNA, the target site is cut, allowing TdT to intercept the double strand break and add nucleotides. Each resulting insertion is sequenced alongside the identity of the TdT variant that generated it. Using this assay, 25,623 unique TdT variants, constructed by site-saturation mutagenesis at strategic positions, were profiled. This resulted in the isolation of several altered-bias TdTs that expanded the capabilities of our TdT-based DNA recording system, Cell History Recording by Ordered Insertion (CHYRON), by increasing the information density of recording through an unbiased TdT and achieving dual-channel recording of two distinct inducers (hypoxia and Wnt) through two differently biased TdTs. Select TdT variants were also tested , revealing concordance between each variant's bias and the bias determined from the multiplexed high throughput assay. Overall, our work, and the multiplex assay it features, should support the continued development of TdT-based DNA recorders, applications of TdT, and further study of the biology of TdT.
PubMed: 38915690
DOI: 10.1101/2024.06.11.598561 -
BioRxiv : the Preprint Server For... Jun 2024Lysine Specific Demethylase 1 (KDM1A / LSD1) regulates mitochondrial respiration and stabilizes HIF-1A (hypoxia-inducible factor 1A). HIF-1A modulates reactive oxygen...
Lysine Specific Demethylase 1 (KDM1A / LSD1) regulates mitochondrial respiration and stabilizes HIF-1A (hypoxia-inducible factor 1A). HIF-1A modulates reactive oxygen species (ROS) levels by increasing cellular glucose uptake, glycolysis, and endogenous antioxidants. The role of KDM1A in cellular ROS response has not previously been described. We determined the role of KDM1A in regulating the ROS response and the utility of KDM1A inhibitors in combination with ROS-inducing cancer therapies. Our results show that KDM1A inhibition sensitized cells to oxidative stress and increased total cellular ROS, which was mitigated by treatment with the antioxidant N-acetyl cysteine. KDM1A inhibition decreased basal mitochondrial respiration and impaired induction of HIF-1A after ROS exposure. Overexpression of HIF-1A salvaged cells from KDM1A inhibition enhanced sensitivity to ROS. Thus we found that increased sensitivity of ROS after KDM1A inhibition was mediated by HIF-1A and depletion of endogenous glutathione. We also show that KDM1A-specific inhibitor bizine synergized with antioxidant-depleting therapies, buthionine sulfoximine, and auranofin in rhabdomyosarcoma cell lines (Rh28 and Rh30). In this study, we describe a novel role for KDM1A in regulating HIF- 1A functions under oxidative stress and found that dual targeting of KDM1A and antioxidant systems may serve as an effective combination anticancer strategy.
PubMed: 38915482
DOI: 10.1101/2024.06.12.597953 -
Biological Research Jun 2024Retinopathy of Prematurity (ROP) is a proliferative retinal vascular disease occurring in the retina of premature infants and is the main cause of childhood blindness....
BACKGROUND
Retinopathy of Prematurity (ROP) is a proliferative retinal vascular disease occurring in the retina of premature infants and is the main cause of childhood blindness. Nowadays anti-VEGF and retinal photocoagulation are mainstream treatments for ROP, but they develop a variety of complications. Hydrogen (H) is widely considered as a useful neuroprotective and antioxidative therapeutic method for hypoxic-ischemic disease without toxic effects. However, whether H provides physiological angiogenesis promotion, neovascularization suppression and glial protection in the progression of ROP is largely unknown.This study aims to investigate the effects of H on retinal angiogenesis, neovascularization and neuroglial dysfunction in the retinas of oxygen-induced retinopathy (OIR) mice.
METHODS
In this study, mice that were seven days old and either wild-type (WT) or Nrf2-deficient (Nrf2-/-) were exposed to 75% oxygen for 5 days and then returned to normal air conditions. Different stages of hydrogen gas (H) inhalation were administered. Vascular obliteration, neovascularization, and blood vessel leakage were analyzed and compared. To count the number of neovascularization endothelial nuclei, routine HE staining of retinal sections was conducted. Immunohistochemistry was performed using DyLight 594 labeled GSL I-isolectin B4 (IB4), as well as primary antibodies against proliferating cell nuclear antigen (PCNA), glial fibrillary acidic protein (GFAP), and Iba-1. Western blots were used to measure the expression of NF-E2-related factor 2 (Nrf2), vascular endothelial growth factor (VEGF), Notch1, Dll4, and HIF-1α. Additionally, the expression of target genes such as NQO1, HO-1, Notch1, Hey1, Hey2, and Dll4 was measured. Human umbilical vein endothelial cells (HUVECs) treated with H under hypoxia were used as an in vitro model. RT-PCR was used to evaluate the mRNA expression of Nrf2, Notch/Dll4, and the target genes. The expression of reactive oxygen species (ROS) was observed using immunofluorescence staining.
RESULTS
Our results indicate that 3-4% H does not disturb retinal physiological angiogenesis, but ameliorates vaso-obliteration and neovascularization in OIR mice. Moreover, H prevents the decreased density and reverses the morphologic and functional changes in retinal astrocytes caused by oxygen-induced injury. In addition, H inhalation reduces microglial activation, especially in the area of neovascularization in OIR mice. H plays a protective role in vascular regeneration by promoting Nrf2 activation and suppressing the Dll4-induced Notch signaling pathway in vivo. Also, H promotes the proliferation of HUVECs under hypoxia by negatively regulating the Dll4/Notch pathway and reducing ROS levels through Nrf2 pathway aligning with our findings in vivo.Moreover, the retinal oxygen-sensing mechanisms (HIF-1α/VEGF) are also involved in hydrogen-mediated retinal revascularization and neovascularization suppression.
CONCLUSIONS
Collectively, our results indicate that H could be a promising therapeutic agent for POR treatment and that its beneficial effect in human ROP might involve the activation of the Nrf2-Notch axis as well as HIF-1α/VEGF pathways.
Topics: Animals; Hydrogen; Oxygen; Retinal Neovascularization; Neuroglia; Mice; Disease Models, Animal; Retinopathy of Prematurity; Mice, Inbred C57BL; Retina; Animals, Newborn; Regeneration; Immunohistochemistry; Retinal Vessels
PubMed: 38915069
DOI: 10.1186/s40659-024-00515-z -
Critical Care (London, England) Jun 2024
Topics: Humans; Extracorporeal Membrane Oxygenation; Hypoxia
PubMed: 38915061
DOI: 10.1186/s13054-024-04972-6 -
Journal of Neuroinflammation Jun 2024Radiation retinopathy (RR) is a major side effect of ocular tumor treatment by plaque brachytherapy or proton beam therapy. RR manifests as delayed and progressive...
Radiation retinopathy (RR) is a major side effect of ocular tumor treatment by plaque brachytherapy or proton beam therapy. RR manifests as delayed and progressive microvasculopathy, ischemia and macular edema, ultimately leading to vision loss, neovascular glaucoma, and, in extreme cases, secondary enucleation. Intravitreal anti-VEGF agents, steroids and laser photocoagulation have limited effects on RR. The role of retinal inflammation and its contribution to the microvascular damage occurring in RR remain incompletely understood. To explore cellular and vascular events after irradiation, we analyzed their time course at 1 week, 1 month and 6 months after rat eyes received 45 Gy X-beam photons. Müller glial cells, astrocytes and microglia were rapidly activated, and these markers of retinal inflammation persisted for 6 months after irradiation. This was accompanied by early cell death in the outer retina, which persisted at later time points, leading to retinal thinning. A delayed loss of small retinal capillaries and retinal hypoxia were observed after 6 months, indicating inner blood‒retinal barrier (BRB) alteration but without cell death in the inner retina. Moreover, activated microglial cells invaded the entire retina and surrounded retinal vessels, suggesting the role of inflammation in vascular alteration and in retinal cell death. Radiation also triggered early and persistent invasion of the retinal pigment epithelium by microglia and macrophages, contributing to outer BRB disruption. This study highlights the role of progressive and long-lasting inflammatory mechanisms in RR development and demonstrates the relevance of this rat model to investigate human pathology.
Topics: Animals; Rats; Retina; Disease Models, Animal; Retinal Diseases; Inflammation; Radiation Injuries, Experimental; Radiation Injuries; Male; Microglia
PubMed: 38915029
DOI: 10.1186/s12974-024-03151-2 -
Effect of apigetrin in pseudo-SARS-CoV-2-induced inflammatory and pulmonary fibrosis in vitro model.Scientific Reports Jun 2024SARS-CoV-2 has become a global public health problem. Acute respiratory distress syndrome (ARDS) is the leading cause of death due to the SARS-CoV-2 infection. Pulmonary...
SARS-CoV-2 has become a global public health problem. Acute respiratory distress syndrome (ARDS) is the leading cause of death due to the SARS-CoV-2 infection. Pulmonary fibrosis (PF) is a severe and frequently reported COVID-19 sequela. In this study, an in vitro model of ARDS and PF caused by SARS-CoV-2 was established in MH-S, THP-1, and MRC-5 cells using pseudo-SARS-CoV-2 (PSCV). Expression of proinflammatory cytokines (IL-6, IL-1β, and TNF-α) and HIF-1α was increased in PSCV-infected MH-S and THP-1 cells, ARDS model, consistent with other profiling data in SARS-CoV-2-infected patients have been reported. Hypoxia-inducible factor-1 alpha (HIF-1α) siRNA and cobalt chloride were tested using this in vitro model. HIF-1α knockdown reduces inflammation caused by PSCV infection in MH-S and THP-1 cells and lowers elevated levels of CTGF, COLA1, and α-SMA in MRC-5 cells exposed to CPMSCV. Furthermore, apigetrin, a glycoside bioactive dietary flavonoid derived from several plants, including Crataegus pinnatifida, which is reported to be a HIF-1α inhibitor, was tested in this in vitro model. Apigetrin significantly reduced the increased inflammatory cytokine (IL-6, IL-1β, and TNF-α) expression and secretion by PSCV in MH-S and THP-1 cells. Apigetrin inhibited the binding of the SARS-CoV-2 spike protein RBD to the ACE2 protein. An in vitro model of PF induced by SARS-CoV-2 was produced using a conditioned medium of THP-1 and MH-S cells that were PSCV-infected (CMPSCV) into MRC-5 cells. In a PF model, CMPSCV treatment of THP-1 and MH-S cells increased cell growth, migration, and collagen synthesis in MRC-5 cells. In contrast, apigetrin suppressed the increase in cell growth, migration, and collagen synthesis induced by CMPSCV in THP-1 and MH-S MRC-5 cells. Also, compared to control, fibrosis-related proteins (CTGF, COLA1, α-SMA, and HIF-1α) levels were over two-fold higher in CMPSV-treated MRC-5 cells. Apigetrin decreased protein levels in CMPSCV-treated MRC-5 cells. Thus, our data suggest that hypoxia-inducible factor-1 alpha (HIF-1α) might be a novel target for SARS-CoV-2 sequela therapies and apigetrin, representative of HIF-1alpha inhibitor, exerts anti-inflammatory and PF effects in PSCV-treated MH-S, THP-1, and CMPVSC-treated MRC-5 cells. These findings indicate that HIF-1α inhibition and apigetrin would have a potential value in controlling SARS-CoV-2-related diseases.
Topics: Humans; Pulmonary Fibrosis; SARS-CoV-2; COVID-19; Hypoxia-Inducible Factor 1, alpha Subunit; Cytokines; Inflammation; Cell Line; Respiratory Distress Syndrome; THP-1 Cells
PubMed: 38914619
DOI: 10.1038/s41598-024-65447-w -
PloS One 2024Obstructive sleep apnea (OSA) is characterized by cyclic normoxic and hypoxic conditions (intermittent hypoxia, IH) induced by the repeated closure of the upper-airway...
Obstructive sleep apnea (OSA) is characterized by cyclic normoxic and hypoxic conditions (intermittent hypoxia, IH) induced by the repeated closure of the upper-airway respiratory tract. As a pathomechanism of OSA, IH results in various comorbidities via chronic inflammation and related pathways. However, the role of other inflammatory cells, such as lymphocytes, has not been well-explored. This study aimed to examine the effects of IH on the distribution and balance of T cell subsets and other related cytokines, and mechanisms in the immune system. We modified OSA mouse model (male C57BL/6N male) using our customized chamber that controls specific sleep and oxygenic cycles. To induce hypoxia, the IH group was repeatedly exposed to 5% O2 and 21% O2 lasting for 120 s each for 7 h daily for 4 weeks. Mice were then subjected to a recovery period of 4 weeks, in which IH stimulation was ceased. T cells and related cytokines were analyzed using flow cytometry and immunohistochemistry. Compared with the control group, the IH group had significantly lower levels of CD4+CD25+Foxp3+ regulatory T cells but higher levels of Th 17, IL-4, HIF-1, and inflammatory cytokines. After the recovery period, these altered changes in the immune cells were recovered, and we found no significant difference in their levels between the control and recovery groups. This study revealed that the Th17/Treg ratio is increased by intermittent hypoxia, and this imbalance can explain immune-related diseases, including recently reported allergies, autoimmune, and even cancer diseases, arising from OSA.
Topics: Animals; Sleep Apnea, Obstructive; T-Lymphocytes, Regulatory; Male; Hypoxia; Th17 Cells; Mice; Disease Models, Animal; Mice, Inbred C57BL; Cytokines; Hypoxia-Inducible Factor 1, alpha Subunit; Interleukin-4
PubMed: 38913648
DOI: 10.1371/journal.pone.0305230