Hyperbaric oxygen therapy attenuates heatstroke-induced hippocampal injury by inhibiting microglial pyroptosis.

Background: Central nervous system (CNS) injury is the most prominent feature of heatstroke and the hippocampus is prone to damage. However, the mechanisms underlying the heatstroke-induced hippocampal injury remain unclear. Hyperbaric oxygen (HBO) therapy prevents CNS injury in heatstroke mice. However, the underlying mechanisms of HBO in heatstroke-induced hippocampal injury remain unclear. This study aimed to elucidate the protective effects of HBO against hippocampal injury and its potential role in microglial pyroptosis in heatstroke rats.Methods: A rat heatstroke model and a heat stress model with a mouse microglial cell line (BV2) were, respectively, used to illustrate the effect of HBO on heat-induced microglial pyroptosis in vivo and in vitro. We used a combination of molecular and histological methods to assess microglial pyroptosis and neuroinflammation both in vivo and in vitro.Results: The results revealed that HBO improved heatstroke-induced survival outcomes, hippocampal injury, and neurological dysfunction in rats. In addition, HBO mitigates microglial pyroptosis and reduces the expression of pro-inflammatory cytokines in the hippocampus of heatstroke rats. In vitro experiments showed that HBO attenuated BV2 cell injury under heat stress. Furthermore, HBO prevented heat-induced pyroptosis of BV2 cells, and the expression of pro-inflammatory cytokines IL-18 and IL-1ß was reduced. Mechanistically, HBO alleviates heatstroke-induced neuroinflammation and hippocampal injury by preventing microglial pyroptosis. Conclusions: In conclusion, HBO attenuates heatstroke-induced neuroinflammation and hippocampal injury by inhibiting microglial pyroptosis.

Diagnosis of severe community-acquired pneumonia caused by Acinetobacter baumannii through next-generation sequencing: a case report.

BACKGROUND: Acinetobacter baumannii is a gram-negative aerobic bacillus that is commonly causes of hospital-acquired infections. Community-acquired pneumonia caused by Acinetobacter baumannii (CAP-Ab) is rare but fatal if diagnosis and treatment are delayed. Conventional culture of clinical specimens is the main method for clinical diagnosis of A. baumannii infections which may suffer from limited positive rate and is time consuming. Timely and precise diagnosis of CAP-Ab remains challenging. CASE PRESENTATION: A 66-year-old man with 24 h history of acute fever and dyspnea was admitted to our hospital. He was diagnosed as severe community acquired pneumonia (CAP), septic shock, respiratory failure and acute kidney injury. Next-generation sequencing (NGS) was performed on the patient's sputum and blood, which identified numerous A. baumannii nucleotide sequences in the sample of sputum and led to the rapid diagnosis and treatment of community acquired pneumonia caused by A. baumannii. This result was confirmed by subsequent sputum culture. CONCLUSIONS: This case described that the successful application of the next generation sequencing assisting the speedy diagnosis of A. baumannii infection provides a new idea for the timely diagnosis of CAP-Ab and highlights that NGS is a promising tool in rapid etiological diagnosis of acute and severe infectious diseases.

INFLUENCES OF HEAT STRESS ON GLUTAMATE TRANSMISSION-DEPENDENT EXPRESSION LEVELS OF IL-1ß and IL-18 IN BV-2 MICROGLIAL CELLS.

ABSTRACT: Objective: This study aimed to explore the impact of heat stress (HS) on glutamate transmission-dependent expression levels of interleukin-1ß (IL-1ß) and IL-18 in BV-2 microglial cells. Methods: BV-2 microglial cells were cultured in vitro , with cells maintained at 37°C serving as the control. The HS group experienced incubation at 40°C for 1 h, followed by further culturing at 37°C for 6 or 12 h. The experimental group was preincubated with glutamate, the glutamate antagonist riluzole, or the mGluR5 agonist, 2-chloro-5-hydroxyphenylglycine (CHPG), before HS. Glutamate content in BV-2 culture supernatant was assessed using colorimetric assay. Moreover, mRNA expression levels of EAAT3 and/or mGluR5 in BV-2 cells were determined via quantitative polymerase chain reaction. Interleukins (IL-1ß and IL-18) in cell culture supernatant were measured using enzyme-linked immunosorbent assay. Western blot analysis was employed to assess protein levels of IL-1ß and IL-18 in BV-2 cells. Results: HS induced a significant release of glutamate and increased the expression levels of mGluR5 and EAAT3 in BV-2 cells. It also triggered the expression levels and release of proinflammatory factors, such as IL-1ß and IL-18, synergizing with the effects of glutamate treatment. Preincubation with both riluzole and CHPG significantly reduced HS-induced glutamate release and mitigated the increased expression levels and release of IL-1ß and IL-18 induced by HS. Conclusion: The findings confirmed that microglia could be involved in HS primarily through glutamate metabolisms, influencing the expression levels and release of IL-1ß and IL-18.

Heat stroke alters hippocampal and cerebellar transmitter metabonomics.

BACKGROUND: The mechanisms underlying heat stroke (HS)-induced hippocampal injury remain unclear. This study aimed to evaluate the HS-induced metabonomics of hippocampal and cerebellar transmitters. METHODS: The HS model was established with male Sprague-Dawley rats subjected to heat exposure of up to 42 °C at a humidity of (55.0±5.0)%. The hippocampal and cerebellar transmitters and metabolites of rats were tested via ultra-high-performance liquid chromatography-mass spectrometry (UPLC-MS/MS). The primary transmitters and metabolites were identified by principal component analysis (PCA) and orthogonal partial least square-discriminant analysis (OPLS-DA). The major metabolic pathways for HS were selected after enrichment. The brain injury was evaluated by histological tests. RESULTS: HS induced hippocampal and cerebellar injuries in rats. HS upregulated the protein levels of hippocampal glutamate, glutamine, gamma-aminobutyric acid, L-tryptophan (Trp), 5-hydroxy-indoleacetic acid, and kynurenine; however, it downregulated asparagine, tryptamine, 5-hydroxytryptophan, melatonin, 3,4-dihydroxyphenylalanine (L-DOPA), and vanillylmandelic acid. HS also sharply elevated the protein levels of cerebellar methionine and Trp, and decreased the levels of serotonin, L-alanine, L-asparagine, L-aspartate, cysteine, norepinephrine, spermine, spermidine, and tyrosine. Hippocampal glutamate, monoamine transmitters, cerebellar aspartate acid, and catecholamine transmitters' metabolic pathways were identified as the main metablic pathways in HS. CONCLUSION: The hippocampus and cerebellum were injured in rats with HS, possibly induced the disorder of hippocampal glutamate and serotonin metabolism, cerebellar aspartate acid and catecholamine transmitter metabolism, and related metabolic pathways.

Protective effect of a hydrogen sulfide donor on balloon injury-induced restenosis via the Nrf2/HIF-1α signaling pathway.

Restenosis is liable to occur following treatment with endovascular interventional therapy. Increasing evidence indicates that hydrogen sulfide (H2S) exhibits numerous physiological properties, including antioxidative and cardioprotective disease properties. Thus, the present study aimed to investigate the anti­restenosis effects of H2S and its protective mechanisms. A balloon dilatation restenosis model was used, in which model Sprague­Dawley rats were treated with sodium hydrosulfide (NaHS: A donor of H2S, 30 µmol/kg) by intraperitoneal injection for 4 weeks. Histological observations of the carotid artery were performed, and H2S production and the expression of Nuclear factor­E2­related factor 2 (Nrf2)/hypoxia­inducible factor (HIF)­1α signaling pathway proteins were measured. In addition, human umbilical vein endothelial cells (HUVECs) were treated with NaHS following the inhibition of Nrf2 or HIF­1α expression. The expression of Nrf2/HIF­1α signaling pathway proteins, tube formation and cell migration were evaluated thereafter. The results demonstrated that NaHS treatment significantly increased H2S production in rats with restenosis, and that neointimal thickness decreased significantly in arteries with restenosis. Furthermore, an increase in H2S production enhanced the nuclear accumulation of Nrf2 and expression of its downstream targets, heme oxygenase­1 and superoxide dismutase, as well as HIF­1α. Similar effects of NaHS on the expression of these proteins were observed in HUVECs. Additionally, these findings indicated that NaHS­induced HIF­1α expression was dependent on Nrf2 expression. NaHS treatment also markedly increased tube formation by upregulating vascular endothelial growth factor expression and cell migration, both of which were mediated by the Nrf2/HIF­1α signaling pathway, and suppressed the migration and proliferation of human vascular smooth muscle cells. Thus, NaHS­mediated H2S production was observed to prevent neointimal hyperplasia, promote activation of the Nrf2/HIF­1α signal pathway, and enhance HUVEC tube formation and migration, thereby exerting protective effects on balloon injury­induced restenosis.

LGR4 Is a Direct Target of MicroRNA-34a and Modulates the Proliferation and Migration of Retinal Pigment Epithelial ARPE-19 Cells.

The pathology of proliferative vitreoretinopathy and proliferative diabetic retinopathy is linked to proliferation, migration, and adhesion of the retinal pigment epithelium. MicroRNA-34a (miR-34a) expression modulates changes in proliferation and migration of retinal pigment epithelial cell line ARPE-19. In this study, we determined that miR-34a interacts with LGR4, identified by bioinformatics using TargetScan Human 5.0, to affect these changes. Double luciferase gene reporter assay confirmed miR-34a involvement in mediating control. miR-34a mimic transfection decreased LGR4 expression. Western blot analysis documented corresponding protein expression inhibition. MTS, Ki67 immunostaining, scratch and transwell testing, along with attachment assay showed that miR-34a upregulation inhibited ARPE-19 cell proliferation, migration and attachment partly through downregulation of LGR4 protein expression. Western blot analysis revealed that both miR-34a upregulation and LGR4 downregulation induced declines in E2F1, p-CDC2, CDK2, CDK4 and CDK6 protein expression. Taken together, miR-34a gene expression upregulation inhibits ARPE-19 cell proliferation, migration and adhesion partly by suppressing LGR4 expression. These results substantiate earlier indications that both miR-34a and LGR4 are potential drug targets to prevent fibrosis in a clinical setting.