Propofol-induced sleep ameliorates cognition impairment in sleep-deprived rats.

PURPOSE: Propofol has been shown to clear sleep debt in rats after sleep deprivation (SD). We examined whether or not propofol-assisted sleep can restore cognitive function in SD rats and explored the possible mechanisms. METHODS: A sleep deprivation model was established by housing 9 to 12 week-old rats to a multiplatform water tank for 96 h. Model rats were then intraperitoneally injected with different concentrations of propofol or 10% fat emulsion (vehicle control). All treatment groups were examined for spatial learning and memory ability in the Morris water maze (MWM). After euthanasia, morphological changes in the hippocampus, hippocampal neurons, and mitochondria were examined by hematoxylin-eosin staining and transmission electron microscopy. Serum and hippocampal levels of IL-1ß, TNF-α, and hippocampal concentrations of ATP and Cyt-c were measured by ELISA (enzyme-linked immunosorbent assay). Immunohistochemistry and Western blotting were performed to assess hippocampal expression of Bcl-2, Bax, and cleaved caspase-3. RESULTS: Results showed that escape latencies in MWM training trials were significantly shorter and target crossings in the memory probe trial significantly greater in propofol-treated SD model rats compared to vehicle-treated SD rats. Propofol also reduced the number of apoptotic bodies in the hippocampal CA1 region. Sleep deprivation reduced IL-1ß and ATP in hippocampus while increasing TNF-α and Cyt-c, and propofol treatment reversed all these changes. There was no significant difference in Bcl-2 expression between propofol- and vehicle-treated SD rats, but pro-apoptotic Bax and cleaved caspase-3 expression levels were significantly reduced by propofol in SD rats. CONCLUSIONS: Propofol-assisted sleep restored cognitive function in SD rats possibly by attenuating mitochondria-mediated neuronal apoptosis in the hippocampus.

Propofol protects hippocampal neurons in sleep-deprived rats by inhibiting mitophagy and autophagy.

BACKGROUND: Sleep deprivation (SD) causes a disturbance in the cognitive function of rats. While propofol has a powerful sedative and hypnotic effect and is an antioxidant, its effect on the cognitive function of rats following SD remains unknown. The purpose of this study was to explore the protective effects of propofol on excessive autophagy and mitophagy in the hippocampus of rats after SD. METHODS: Adult male rats were intraperitoneally injected with 30 mg/kg of propofol after 96 hours of SD. Then we evaluated the effect of propofol on the cognitive function of sleep deprived rats by the Morris water maze. Transmission electron microscopy, Western blotting, PCR, immunohistochemistry, autophagy enhancer and autophagy inhibitor were used to study the effect of propofol on hippocampal neurons of rat with excessive autophagy and mitophagy. RESULTS: The behavioral experimental results of the Morris water maze showed that propofol improved the learning and memory ability of sleep-deprived rats. The expression of Beclin1, PINK1, parkin, p62, and LC3 protein increased significantly after sleep deprivation. While the intervention of propofol could significantly reduce the expression of these proteins, rapamycin treatment eliminated this effect. CONCLUSIONS: Our findings showed that propofol could reduce the impairment of learning and memory in sleep-deprived rats by inhibiting excessive autophagy and mitophagy in hippocampal neurons. This strategy may provide an application basis for the clinical use of propofol in patients with chronic insomnia.

High-Dose Dexmedetomidine Promotes Apoptosis in Fetal Rat Hippocampal Neurons.

OBJECTIVE: Dexmedetomidine (DEX) is a potent a2-adrenoceptor agonist that has sedative, analgesic, and anxiolytic effects. Its primary clinical use is as an adjunct to general anesthesia to reduce anesthetic doses, provide analgesia and sedation in the preoperative and postoperative periods, it also used in intensive care units (ICUs). However, high concentrations of DEX may have toxic effects on neurons and cause neuronal apoptosis. This study aimed to evaluate the potential proapoptotic effects of DEX on fetal rat hippocampal neurons. METHODS: Primary hippocampal were cultured in vitro for 8 days and incubated with different DEX concentrations for 3 h. Cell viability was measured using cell counting kit-8 assays. Cell apoptosis was evaluated using flow cytometry. The expression of apoptosis-related proteins, such as cleaved caspase-3, caspase-9, Cyt-c, Bax, and Bcl-2, was measured by Western blotting. The mitochondrial ATP levels, Δψm, and ROS analyzed were conducted. RESULTS: High concentrations of DEX (≥100 µM) significantly reduced cell viability, induced neuronal apoptosis, upregulated the protein expression of cleaved caspase 3, Bax, cleaved caspase 9, and Cyt-c. DEX also considerably promoted the release of ROS. However, DEX (≥100 µM) downregulated the protein expression of Bcl-2, decreased the mitochondrial membrane potential (MTP), and reduced ATP synthesis. CONCLUSION: High concentrations of dexmedetomidine produced toxic effects on neurons and caused neuronal apoptosis.

Expression level of long non-coding RNA colon adenocarcinoma hypermethylated serves as a novel prognostic biomarker in patients with thyroid carcinoma.

The present study attempts to identify the prognostic value and potential mechanism of action of colorectal adenocarcinoma hypermethylated (CAHM) in thyroid carcinoma (THCA) by using the RNA sequencing (RNA-seq) dataset from The Cancer Genome Atlas (TCGA). The functional mechanism of CAHM was explored by using RNA-seq dataset and multiple functional enrichment analysis approaches. Connectivity map (CMap) online analysis tool was also used to predict CAHM targeted drugs. Survival analysis suggests that THCA patients with high CAHM expression have lower risk of death than the low CAHM expression (log-rank P=0.022, adjusted P=0.011, HR = 0.187, 95% confidence interval (CI) = 0.051-0.685). Functional enrichment of CAHM co-expression genes suggests that CAHM may play a role in the following biological processes: DNA repair, cell adhesion, DNA replication, vascular endothelial growth factor receptor, Erb-B2 receptor tyrosine kinase 2, ErbB and thyroid hormone signaling pathways. Functional enrichment of differentially expressed genes (DEGs) between low- and high-CAHM phenotype suggests that different CAHM expression levels may have the following differences in biological processes in THCA: cell adhesion, cell proliferation, extracellular signal-regulated kinase (ERK) 1 (ERK1) and ERK2 cascade, G-protein coupled receptor, chemokine and phosphatidylinositol-3-kinase-Akt signaling pathways. Connectivity map have identified five drugs (levobunolol, NU-1025, quipazine, anisomycin and sulfathiazole) for CAHM targeted therapy in THCA. Gene set enrichment analysis (GSEA) suggest that low CAHM phenotype were notably enriched in p53, nuclear factor κB, Janus kinase-signal transducer and activators of transcription, tumor necrosis factor, epidermal growth factor receptor and other signaling pathways. In the present study, we have identified that CAHM may serve as novel prognostic biomarkers for predicting overall survival (OS) in patients with THCA.

Potential role of the cAMP/PKA/CREB signalling pathway in hypoxic preconditioning and effect on propofol­induced neurotoxicity in the hippocampus of neonatal rats.

Hypoxic preconditioning (HPC) is neuroprotective against ischaemic brain injury; however, the roles of potential anti­apoptotic signals in this process have not been assessed. To elucidate the molecular mechanisms involved in HPC­induced neuroprotection, the effects of HPC on the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA)/cAMP response element­binding protein (CREB) signalling pathway and apoptosis in Sprague­Dawley pups (postnatal day 7) treated with propofol were investigated. Western blot and histological analyses demonstrated that HPC exerts multiple effects on the hippocampus, including the upregulation of cAMP and phosphorylation of CREB. These effects were partially blocked by intracerebroventricular injection of the protein kinase antagonist H89 (5 µmol/5 µl). Notably, the level of cleaved caspase­3 was significantly downregulated by treatment with the cAMP agonist Sp­cAMP (20 nmol/5 µl). The results indicate that propofol increased the level of cleaved caspase­3 and Bax by suppressing the activity of cAMP­dependent proteins and Bcl­2; thus, HPC prevents propofol from triggering apoptosis via the cAMP/PKA/CREB signalling pathway.

Dexmedetomidine attenuates the neurotoxicity of propofol toward primary hippocampal neurons in vitro via Erk1/2/CREB/BDNF signaling pathways.

BACKGROUND: Propofol is a commonly used general anesthetic for the induction and maintenance of anesthesia and critical care sedation in children, which may add risk to poor neurodevelopmental outcome. We aimed to evaluate the effect of propofol toward primary hippocampal neurons in vitro and the possibly neuroprotective effect of dexmedetomidine pretreatment, as well as the underlying mechanism. MATERIALS AND PROCEDURES: Primary hippocampal neurons were cultured for 8 days in vitro and pretreated with or without dexmedetomidine or phosphorylation inhibitors prior to propofol exposure. Cell viability was measured using cell counting kit-8 assays. Cell apoptosis was evaluated using a transmission electron microscope and flow cytometry analyses. Levels of mRNAs encoding signaling pathway intermediates were assessed using qRT-PCR. The expression of signaling pathway intermediates and apoptosis-related proteins was determined by Western blotting. RESULTS: Propofol significantly reduced cell viability, induced neuronal apoptosis, and downregulated the expression of the BDNF mRNA and the levels of the phospho-Erk1/2 (p-Erk1/2), phospho-CREB (p-CREB), and BDNF proteins. The dexmedetomidine pretreatment increased neuronal viability and alleviated propofol-induced neuronal apoptosis and rescued the propofol-induced downregulation of both the BDNF mRNA and the levels of the p-Erk1/2, p-CREB, and BDNF proteins. However, this neuroprotective effect was abolished by PD98059, H89, and KG501, further preventing the dexmedetomidine pretreatment from rescuing the propofol-induced downregulation of the BDNF mRNA and p-Erk1/2, p-CREB, and BDNF proteins. CONCLUSION: Dexmedetomidine alleviates propofol-induced cytotoxicity toward primary hippocampal neurons in vitro, which correlated with the activation of Erk1/2/CREB/BDNF signaling pathways.

Integrated Bioinformatics Analysis Identifies Hub Genes Associated with the Pathogenesis and Prognosis of Esophageal Squamous Cell Carcinoma.

Esophageal squamous cell carcinoma (ESCC) accounts for over 90% of all esophageal tumors. However, the molecular mechanism underlying ESCC development and prognosis remains unclear, and there are still no effective molecular biomarkers for diagnosing or predicting the clinical outcome of patients with ESCC. Here, using bioinformatics analyses, we attempted to identify potential biomarkers and therapeutic targets for ESCC. Differentially expressed genes (DEGs) between ESCC and normal esophageal tissue samples were obtained through comprehensive analysis of three publicly available gene expression profile datasets from the Gene Expression Omnibus database. The biological roles of the DEGs were identified by Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Moreover, the Cytoscape 3.7.1 platform and subsidiary tools such as Molecular Complex Detection (MCODE) and CytoHubba were used to visualize the protein-protein interaction (PPI) network of the DEGs and identify hub genes. A total of 345 DEGs were identified between normal esophageal and ESCC samples, which were enriched in the KEGG pathways of the cell cycle, endocytosis, pancreatic secretion, and fatty acid metabolism. Two of the highest scoring models were selected from the PPI network using Molecular Complex Detection. Moreover, CytoHubba revealed 21 hub genes with a valuable influence on the progression of ESCC in these patients. Among these, the high expression levels of five genes-SPP1, SPARC, BGN, POSTN, and COL1A2-were associated with poor disease-free survival of ESCC patients, as indicated by survival analysis. Taken together, we identified that elevated expression of five hub genes, including SPP1, is associated with poor prognosis in ESCC patients, which may serve as potential prognostic biomarkers or therapeutic target for ESCC.

Dexmedetomidine attenuates the propofol-induced long-term neurotoxicity in the developing brain of rats by enhancing the PI3K/Akt signaling pathway.

BACKGROUND: Propofol induces short- and long-term neurotoxicity. Our previous study showed that dexmedetomidine (Dex) can attenuate the propofol-induced acute neurotoxicity in rodents by enhancing the PI3K/Akt signaling. However, whether treatment of young rats with Dex could protect them from long-term neurotoxicity induced by propofol is unclear. MATERIALS AND METHODS: Seven-day-old male Sprague Dawley rats were randomized and injected intraperitoneally with saline (100 µL, NS), propofol (100 mg/kg), Dex (75 µg/kg), propofol (100 mg/kg) plus Dex (25, 50 or 75 µg/kg), 10% dimethyl sulfoxide (DMSO, 100 µL) or TDZD-8 (a GSK3ß inhibitor, 1 mg/kg), or intracerebroventricularly with DMSO (5 µL) or LY294002 (a PI3K inhibitor, 25 µg/5 µL DMSO). Other rats in the experimental group were injected with the same doses of propofol, Dex and LY294002 or TDZD-8. All the rats were monitored until they were 9 weeks old. Their spatial learning and memory were tested by Morris water maze. The neuronal apoptosis, expression of PSD95, expression and phosphorylation of Akt and GSK3ß and synaptic ultrastructures were determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling, immunohistochemistry, Western blot and transmission electron microscopy assays, respectively. RESULTS: Compared with the NS control group, young rats injected with intralipid, Dex, TDZD-8, LY294002 or DMSO alone did not show any significant change as they aged. Propofol significantly increased the escape latency time, hippocampal neuroapoptosis and synaptic ultrastructural changes but decreased the relative levels of PSD95 expression, and Akt and GSK3ß phosphorylation in the developing hippocampus of the rats. The neuronal toxic effects of propofol were significantly mitigated by the pretreatment with a higher dose of Dex. The neuroprotective effect of Dex was enhanced by the treatment with TDZD-8, but was completely abrogated by the treatment with LY294002. CONCLUSION: Our results indicated that the pretreatment of young rats with Dex attenuated the propofol-induced long-term neurotoxicity in their developing hippocampus by enhancing the PI3K/Akt signaling.

Hypoxic preconditioning reduces propofol-induced neuroapoptosis via regulation of Bcl-2 and Bax and downregulation of activated caspase-3 in the hippocampus of neonatal rats.

OBJECTIVE:  Evidence has shown that propofol may cause widespread apoptotic neurodegeneration. Hypoxic preconditioning (HPC) was previously demonstrated to provide neuroprotection and brain recovery from either acute or chronic neurodegeneration in several cellular and animal models. Therefore, the present study was designed to investigate the protective effects of hypoxic preconditioning on apoptosis caused by propofol in neonatal rats. METHODS: Propofol (100 mg/kg) was given to 7-day-old (P7) Sprague Dawley pups. Before the propofol injection, hypoxic preconditioning was administered by subjecting rats to five cycles of 10 min of hypoxia (8% O2) and 10 min of normoxia (21% O2), then 2 h of room air. We detected neuronal structure changes and apoptosis by hematoxylin and eosin (HE) staining and TUNEL assay, respectively. Bcl-2, Bax and cleaved-caspase-3 levels were quantified using Western blotting and immunohistochemistry. RESULT:  After treatment with propofol, Bcl-2 levels decreased and Bax and cleaved-caspase-3 levels increased. However, our results suggest that hypoxic preconditioning could reverse this change. Conclusion: Our results indicate that pretreatment with hypoxic preconditioning prevents propofol-induced neuroapoptosis by increasing the levels of Bcl-2 and decreasing the levels of Bax and cleaved-caspase-3.

A novel glycan modifies the flagellar filament proteins of the oral bacterium Treponema denticola.

While protein glycosylation has been reported in several spirochetes including the syphilis bacterium Treponema pallidum and Lyme disease pathogen Borrelia burgdorferi, the pertinent glycan structures and their roles remain uncharacterized. Herein, a novel glycan with an unusual chemical composition and structure in the oral spirochete Treponema denticola, a keystone pathogen of periodontitis was reported. The identified glycan of mass 450.2 Da is composed of a monoacetylated nonulosonic acid (Non) with a novel extended N7 acyl modification, a 2-methoxy-4,5,6-trihydroxy-hexanoyl residue in which the Non has a pseudaminic acid configuration (L-glycero-L-manno) and is ß-linked to serine or threonine residues. This novel glycan modifies the flagellin proteins (FlaBs) of T. denticola by O-linkage at multiple sites near the D1 domain, a highly conserved region of bacterial flagellins that interact with Toll-like receptor 5. Furthermore, mutagenesis studies demonstrate that the glycosylation plays an essential role in the flagellar assembly and motility of T. denticola. To our knowledge, this novel glycan and its unique modification sites have not been reported previously in any bacteria.