Identification of differential m6A RNA methylomes and ALKBH5 as a potential prevention target in the developmental neurotoxicity induced by multiple sevoflurane exposures.

Sevoflurane, as a commonly used inhaled anesthetic for pediatric patients, has been reported that multiple sevoflurane exposures are associated with a greater risk of developing neurocognitive disorder. N6-Methyladenosine (m6A), as the most common mRNA modification in eukaryotes, has emerged as a crucial regulator of brain function in processes involving synaptic plasticity, learning and memory, and neurodevelopment. Nevertheless, the relevance of m6A RNA methylation in the multiple sevoflurane exposure-induced developmental neurotoxicity remains mostly elusive. Herein, we evaluated the genome-wide m6A RNA modification and gene expression in hippocampus of mice that received with multiple sevoflurane exposures using m6A-sequencing (m6A-seq) and RNA-sequencing (RNA-seq). We discovered 19 genes with differences in the m6A methylated modification and differential expression in the hippocampus. Among these genes, we determined that a total of nine differential expressed genes may be closely associated with the occurrence of developmental neurotoxicity induced by multiple sevoflurane exposures. We further found that the alkB homolog 5 (ALKBH5), but not methyltransferase-like 3 (METTL3) and Wilms tumor 1-associated protein (WTAP), were increased in the hippocampus of mice that received with multiple sevoflurane exposures. And the IOX1, as an inhibitor of ALKBH5, significantly improved the learning and memory defects and reduced neuronal damage in the hippocampus of mice induced by multiple sevoflurane exposures. The current study revealed the role of m6A methylated modification and m6A-related regulators in sevoflurane-induced cognitive impairment, which might provide a novel insight into identifying biomarkers and therapeutic strategies for inhaled anesthetic-induced developmental neurotoxicity.

Minocycline alleviates microglia ferroptosis by inhibiting HO-1 during cerebral ischemia-reperfusion injury.

OBJECTIVE: Ischemic stroke is a leading cause of death and disability in individuals worldwide. Cerebral ischemia-reperfusion injury (CIRI) typically results in severe secondary injury and complications following reperfusion therapy. Microglia play critical roles in the inflammatory reaction of CIRI. However, less attention has been given to microglial death in this process. Our study aims to explore microglial death in CIRI and the effects and mechanism of minocycline treatment on microglia. METHODS: A middle cerebral artery occlusion (MCAO) model was applied to induce CIRI in rats. At 0 h, 24 h and 48 h post-operation, rats were intraperitoneally injected with 45 mg/kg minocycline. Neurological deficit scoring, 2,3,5-triphenyltetrazolium chloride (TTC) staining, assessment of activated microglia and examination of mitochondrial structure were conducted and checked at 72 h after reperfusion. Additionally, an in vitro model of oxygen-glucose deprivation/reperfusion (OGD/R) model was established. BV-2 cells were treated with various pharmacological inhibitors of cell death or minocycline. Cell viability, lipid peroxidation, mitochondrial structure and function, and labile Fe2+ and ferroptosis-associated gene/protein levels were measured. Hemin was used for further validation after transcriptome analysis. RESULTS: In the MCAO and OGD/R models, ferroptosis was identified as a major form of microglial death. Minocycline inhibited microglia ferroptosis by reducing HO-1 expression. In addition, minocycline improved mitochondrial membrane potential, mitochondrial structures and microglial survival in vivo. Minocycline also decreased labile Fe2+ levels, lipid peroxidation, and expression of ferritin heavy chain (FTH) and it improved mitochondrial structure and function in vitro. Upregulation of HO-1 counteracted the protective effect of minocycline. CONCLUSION: Ferroptosis is a major form of microglial death in CIRI. The protective mechanism of minocycline in CIRI partially hinges on its ability to effectively ameliorate microglia ferroptosis by downregulating HO-1 expression. Consequently, targeting microglia ferroptosis is a promising treatment for CIRI.

Opioid-free anaesthesia reduces postoperative nausea and vomiting after thoracoscopic lung resection: a randomised controlled trial.

BACKGROUND: Intraoperative opioid use has a positive relationship with postoperative nausea and vomiting (PONV), and opioid-free anaesthesia (OFA) might reduce PONV. We investigated whether OFA compared with opioid-based anaesthesia would reduce PONV during the first 2 postoperative days among patients undergoing thoracoscopic lung resection. METHODS: In this randomised controlled trial, 120 adult patients were randomly assigned (1:1, stratified by sex) to receive either OFA with esketamine, dexmedetomidine, and sevoflurane, or opioid-based anaesthesia with sufentanil and sevoflurane. A surgical pleth index (SPI) of 20-50 was applied for intraoperative analgesia provision. All subjects received PONV prophylaxis (dexamethasone and ondansetron) and multimodal analgesia (flurbiprofen axetil, ropivacaine wound infiltration, and patient-controlled sufentanil). The primary outcome was the occurrence of PONV during the first 48 h after surgery. RESULTS: The median age was 53 yr and 66.7% were female. Compared with opioid-based anaesthesia, OFA significantly reduced the incidence of PONV (15% vs 31.7%; odds ratio [OR]=0.38, 95% confidence interval [CI], 0.16-0.91; number needed to treat, 6; P=0.031). Secondary and safety outcomes were comparable between groups, except that OFA led to a lower rate of vomiting (OR=0.23, 95% CI, 0.08-0.77) and a longer length of PACU stay (median difference=15.5 min, 95% CI, 10-20 min). The effects of OFA on PONV did not differ in the prespecified subgroups of sex, smoking status, and PONV risk scores. CONCLUSIONS: In the context of PONV prophylaxis and multimodal analgesia, SPI-guided opioid-free anaesthesia halved the incidence of PONV after thoracoscopic lung resection, although it was associated with a longer stay in the PACU. CLINICAL TRIAL REGISTRATION: Chinese Clinical Trial Registry (ChiCTR2200059710).

Dexmedetomidine attenuates renal ischemia-reperfusion injury through activating PI3K/Akt-eNOS signaling via α2 adrenoreceptors in renal microvascular endothelial cells.

Renal microvascular endothelial cells (RMECs), which are closely related to regulation of vascular reactivity and modulation of inflammation, play a crucial role in the process of renal ischemia and reperfusion (I/R) injury. Previous studies have reported the protective effects of dexmedetomidine (DEX) against renal I/R injury, but little is known about the role of DEX on RMECs. This study aimed to investigate whether DEX alleviated renal I/R injury via acting on the RMECs. Mice underwent bilateral renal artery clamping for 45 min followed by reperfusion for 48 h, and the cultured neonatal mice RMECs were subjected to hypoxia for 1 h followed by reoxygenation (H/R) for 24 h. The results suggest that DEX alleviated renal I/R injury in vivo and improved cell viability of RMECs during H/R injury in vitro. Gene sequencing revealed that the PI3K/Akt was the top enriched signaling pathway and the endothelial cells were widely involved in renal I/R injury. DEX activated phosphorylation of PI3K and Akt, increased eNOS expression, and attenuated inflammatory responses. In addition, the results confirmed the distribution of α2 adrenoreceptor (α2 -AR) in RMECs. Furthermore, the protective effects of DEX against renal I/R injury were abolished by α2 -AR antagonist (atipamezole), which was partly reversed by the PI3K agonist (740 Y-P). These findings indicated that DEX protects against renal I/R injury by activating the PI3K/Akt-eNOS pathway and inhibiting inflammation responses via α2 -AR in RMECs.

Single-nucleus Atlas of Sevoflurane-induced Hippocampal Cell Type- and Sex-specific Effects during Development in Mice.

BACKGROUND: Multiple neonatal exposures to sevoflurane induce neurocognitive dysfunctions in rodents. The lack of cell type-specific information after sevoflurane exposure limits the mechanistic understanding of these effects. In this study, the authors tested the hypothesis that sevoflurane exposures alter the atlas of hippocampal cell clusters and have neuronal and nonneuronal cell type-specific effects in mice of both sexes. METHODS: Neonatal mice were exposed to 3% sevoflurane for 2 h at postnatal days 6, 8, and 10 and analyzed for the exposure effects at postnatal day 37. Single-nucleus RNA sequencing was performed in the hippocampus followed by in situ hybridization to validate the results of RNA sequencing. The Morris Water Maze test was performed to test neurocognitive function. RESULTS: The authors found sex-specific distribution of hippocampal cell types in control mice alongside cell type- and sex-specific effects of sevoflurane exposure on distinct hippocampal cell populations. There were important changes in male but not in female mice after sevoflurane exposure regarding the proportions of cornu ammonis 1 neurons (control vs. sevoflurane, males: 79.9% vs. 32.3%; females: 27.3% vs. 24.3%), dentate gyrus (males: 4.2% vs. 23.4%; females: 36.2% vs. 35.8%), and oligodendrocytes (males: 0.6% vs. 6.9%; females: 5.9% vs. 7.8%). In male but not in female mice, sevoflurane altered the number of significantly enriched ligand-receptor pairs in the cornu ammonis 1, cornu ammonis 3, and dente gyrus trisynaptic circuit (control vs. sevoflurane, cornu ammonis 1-cornu ammonis 3: 18 vs. 42 in males and 15 vs. 21 in females; cornu ammonis 1-dentate gyrus: 21 vs. 35 in males and 12 vs. 20 in females; cornu ammonis 3-dentate gyrus: 25 vs. 45 in males and 17 vs. 20 in females), interfered with dentate gyrus granule cell neurogenesis, hampered microglia differentiation, and decreased cornu ammonis 1 pyramidal cell diversity. Oligodendrocyte differentiation was specifically altered in females with increased expressions of Mbp and Mag. In situ hybridization validated the increased expression of common differentially expressed genes. CONCLUSIONS: This single-nucleus RNA sequencing study reveals the hippocampal atlas of mice, providing a comprehensive resource for the neuronal and nonneuronal cell type- and sex-specific effects of sevoflurane during development.

Neonatal exposure to sevoflurane impairs preference for social novelty in C57BL/6 female mice at early-adulthood.

Social interaction deficit is core symptom of children with autism, owing to interaction of genetic predisposition and environmental toxins. Sevoflurane could induce neurotoxicity in developing brain in rodent models. This study aims to investigate whether sevoflurane anesthesia in neonatal period could impair social behaviors in male and female mice. Twenty-eight male and thirty-one female mice were randomly assigned to receive 3.0% sevoflurane or 60% oxygen on postnatal day 6. They were tested for social interaction behaviors at one- and two-month-old. In addition, the cortex and hippocampus of neonatal mice undergoing sevoflurane anesthesia were harvested for immunoblotting analysis. As a result, both male and female mice undergoing sevoflurane anesthesia showed strong sociability and weak preference for social novelty at juvenile age. In addition, the male mice developed normal preference for social novelty at early-adulthood; However, the female mice remained weak preference for social novelty. Furthurmore, sevoflurane anesthesia could decrease the levels of PSD95 but not Neuroligin-1 in the hippocampus but not cortex of neonatal mice. In conclusion, sevoflurane anesthesia in neonatal period could disturb development of social memory and impair preference for social novelty in female mice at early-adulthood, with the potential mechanism of decreasing PSD95 expression in the hippocampus of C57BL/6 mice.

Dexmedetomidine Attenuates Total Body Radiation-Induced Acute Liver Injury in Mice Through the Nrf2/HO-1 Pathway.

BACKGROUND: The purpose of this study was to investigate the protective effects of dexmedetomidine (DEX) on total body radiation-induced acute liver injury in mice and to explore the possible mechanisms. METHODS: A total of 40 mice were randomly divided into the Control group (Group C), Dexmedetomidine group (Group Dex), Radiation group (Group R), and Group R+Dex. Mice in Group Dex and Group R+Dex were intraperitoneally injected with 10 µg/mL Dex at 50 mg/kg. Both Group C and Group R received normal saline instead of Dex. Mice were treated via continuous administration for 10 days and injection once a day (pre-administration for 3 days and 7 days after radiation). One hour after administration on the third day, the mice in Group R and R+Dex received total body radiation with a total dose of 6 Gy at a rate of 2 Gy/min. Group C received sham radiation. Levels of aspartate aminotransferase (AST), serum alanine aminotransferase (ALT), and liver levels of tumor necrosis factor (TNF-α), interleukin-1ß (IL-1ß), reactive oxygen species (ROS), superoxide dismutase (SOD), malondialdehyde (MDA) were measured. HE staining was employed to evaluate the pathological changes in liver tissues, and the expressions of Nrf2 and HO-1 proteins in the liver were measured by western blot. RESULTS: Compared with group C, serum levels of AST and ALT, liver TNF-α, IL-1ß, MDA, and ROS levels increased, and SOD decreased in Group R. Group R mice had higher liver injury scores, and the protein expressions of Nrf2 and HO-1 proteins were lower (p ＜ 0.05). Compared with Group R, the levels of AST, ALT, TNF-α, IL-1ß, MDA, and ROS decreased, SOD increased, liver injury scores were lower, and the expressions of Nrf2 and HO-1 proteins were higher in the Group R+Dex group (all p ＜ 0.05). CONCLUSIONS: Dex exhibits a protective effect on reducing acute radiation-induced liver injury and oxidative stress, and the mechanism may be associated with the activation of Nrf2/HO-1 pathways.

Inhibition of cathepsin S attenuates myocardial ischemia/reperfusion injury by suppressing inflammation and apoptosis.

Myocardial ischemia/reperfusion (I/R) injury leads to high mortality and morbidity due to the incomplete understanding of the underlying mechanism and the consequent lack of effective therapy. The present study revealed and validated key candidate genes in relation to inflammation and apoptosis pathways underlying myocardial I/R injury. Cathepsin S was identified as the top hub protein based on the protein-protein interaction analysis, and, thus, its role during myocardial I/R injury was further investigated. Myocardial I/R in mice resulted in significantly increased levels of myocardial injury biomarkers (cardiac troponin I, lactic dehydrogenase, and creatinine kinase-MB) and inflammatory cytokines (interleukin-1ß [IL-1ß], IL-6, and tumor necrosis factor-α), elevated apoptosis rate, and upregulated protein expression of cleaved caspase-8, cleaved caspase-3, and cleaved poly ADP-ribose polymerase. These abovementioned changes were blocked by two different selective cathepsin S inhibitors, LY3000328 or MIV-247. Moreover, Kaplan-Meier survival plot showed that cathepsin S inhibition improved 21-day survival rate following myocardial I/R injury. This study demonstrated that the inhibition of cathepsin S alleviated myocardial I/R-induced injury by suppressing inflammation and apoptosis, which may be used in clinical applications of cardioprotection.

Inhibiting BDNF/TrkB.T1 receptor improves resiniferatoxin-induced postherpetic neuralgia through decreasing ASIC3 signaling in dorsal root ganglia.

BACKGROUND: Postherpetic neuralgia (PHN) is a devastating complication after varicella-zoster virus infection. Brain-derived neurotrophic factor (BDNF) has been shown to participate in the pathogenesis of PHN. A truncated isoform of the tropomyosin receptor kinase B (TrkB) receptor TrkB.T1, as a high-affinity receptor of BDNF, is upregulated in multiple nervous system injuries, and such upregulation is associated with pain. Acid-sensitive ion channel 3 (ASIC3) is involved in chronic neuropathic pain, but its relation with BDNF/TrkB.T1 in the peripheral nervous system (PNS) during PHN is unclear. This study aimed to investigate whether BDNF/TrkB.T1 contributes to PHN through regulating ASIC3 signaling in dorsal root ganglia (DRGs). METHODS: Resiniferatoxin (RTX) was used to induce rat PHN models. Mechanical allodynia was assessed by measuring the paw withdrawal thresholds (PWTs). Thermal hyperalgesia was determined by detecting the paw withdrawal latencies (PWLs). We evaluated the effects of TrkB.T1-ASIC3 signaling inhibition on the behavior, neuronal excitability, and inflammatory response during RTX-induced PHN. ASIC3 short hairpin RNA (shRNA) transfection was used to investigate the effect of exogenous BDNF on inflammatory response in cultured PC-12 cells. RESULTS: RTX injection induced mechanical allodynia and upregulated the protein expression of BDNF, TrkB.T1, ASIC3, TRAF6, nNOS, and c-Fos, as well as increased neuronal excitability in DRGs. Inhibition of ASIC3 reversed the abovementioned effects of RTX, except for BDNF and TrkB.T1 protein expression. In addition, inhibition of TrkB.T1 blocked RTX-induced mechanical allodynia, activation of ASIC3 signaling, and hyperexcitability of neurons. RTX-induced BDNF upregulation was found in both neurons and satellite glia cells in DRGs. Furthermore, exogenous BDNF activated ASIC3 signaling, increased NO level, and enhanced IL-6, IL-1ß, and TNF-α levels in PC-12 cells, which was blocked by shRNA-ASIC3 transfection. CONCLUSION: These findings demonstrate that inhibiting BDNF/TrkB.T1 reduced inflammation, decreased neuronal hyperexcitability, and improved mechanical allodynia through regulating the ASIC3 signaling pathway in DRGs, which may provide a novel therapeutic target for patients with PHN.

Dexmedetomidine post-treatment attenuates cardiac ischaemia/reperfusion injury by inhibiting apoptosis through HIF-1α signalling.

Hypoxia-inducible factor 1α (HIF-1α) plays a critical role in the apoptotic process during cardiac ischaemia/reperfusion (I/R) injury. This study aimed to investigate whether post-treatment with dexmedetomidine (DEX) could protect against I/R-induced cardiac apoptosis in vivo and in vitro via regulating HIF-1α signalling pathway. Rat myocardial I/R was induced by occluding the left anterior descending artery for 30 minutes followed by 6-hours reperfusion, and cardiomyocyte hypoxia/reoxygenation (H/R) was induced by oxygen-glucose deprivation for 6 hours followed by 3-hours reoxygenation. Dexmedetomidine administration at the beginning of reperfusion or reoxygenation attenuated I/R-induced myocardial injury or H/R-induced cell death, alleviated mitochondrial dysfunction, reduced the number of apoptotic cardiomyocytes, inhibited the activation of HIF-1α and modulated the expressions of apoptosis-related proteins including BCL-2, BAX, BNIP3, cleaved caspase-3 and cleaved PARP. Conversely, the HIF-1α prolyl hydroxylase-2 inhibitor IOX2 partly blocked DEX-mediated cardioprotection both in vivo and in vitro. Mechanistically, DEX down-regulated HIF-1α expression at the post-transcriptional level and inhibited the transcriptional activation of the target gene BNIP3. Post-treatment with DEX protects against cardiac I/R injury in vivo and H/R injury in vitro. These effects are, at least in part, mediated via the inhibition of cell apoptosis by targeting HIF-1α signalling.

MicroRNA-22 exerts its neuroprotective and angiogenic functions via regulating PI3K/Akt signaling pathway in cerebral ischemia-reperfusion rats.

The aims of this study were to study the effects of miR-2 on cerebral ischemia-reperfusion rats and to explore its further mechanism. Rats were assigned into sham, model, miR-22 control and miR-22 groups. Observation of neurological behaviors at 24 h after operation found that neurological functions were severely damaged in the model and miR-22 control groups and these damages were improved by miR-22. RT-PCR indicated that miR-22 mRNA level in the brain tissue was significantly decreased in the model and miR-22 control groups, but increased in the miR-22 group. TTC staining showed increased percentage of cerebral infarction volume in the model and miR-22 control groups and this increase was reduced by miR-22. Immunohistochemistry showed increased densities of CD34+ and VEGF+ microvessels in the cortex in the model and miR-22 control groups, which were further increased in the miR-22 group. ELISA showed increased serum VEGF and Ang-1 levels in the model and miR-22 control groups, which were also further increased in the miR-22 group. Western blot analysis showed increased phosphorylation level of PI3K and Akt in brain tissue in the model and miR-22 control groups, which were further increased in the miR-22 group. Administration of LY294002, a specific PI3K pathway inhibitor, significantly reversed all the effects of miR-22 on rats in the model group. miR-22 exerts its neuroprotective and angiogenic functions via the PI3K/Akt signaling pathway, at least partly, in rats under cerebral ischemia-reperfusion.

Effects of Haloperidol on Delirium in Adult Patients: A Systematic Review and Meta-Analysis.

OBJECTIVE: The aim of this systematic review and meta-analysis was to investigate whether or not the use of haloperidol could reduce the incidence of delirium in adult patients. SUBJECTS AND METHODS: PubMed, Embase, the Cochrane Library, Elsevier, Wiley, and Ovid were searched for randomized controlled trials and prospective interventional cohort studies that compared haloperidol with placebo for delirium prophylaxis or with second generation antipsychotics for delirium treatment. The primary end point was the incidence and severity of delirium. After reviewing 272 relevant articles, 10 studies with 1,861 patients were finally included (haloperidol vs. placebo in 8 studies [n = 1,734], and haloperidol vs. second-generation antipsychotics in 2 studies [n = 127]). Revman 5.3 was used for the data analysis. RESULTS: Compared with placebo, a high dose of prophylactic haloperidol (≥5 mg/day) may help reduce the incidence of delirium in surgical patients (risk ratio 0.50, 95% CI 0.32, 0.79). There were no differences in the duration of delirium, QTc interval prolongation, extrapyramidal symptoms, intensive care unit stay, hospital stay, or mortality between the haloperidol and placebo groups. For delirium treatment, haloperidol exhibited similar effects as the second-generation antipsychotics. CONCLUSIONS: In this study, the limited available data revealed that prophylaxis haloperidol at a dose of ≥5 mg/day might help reduce delirium in adult surgical patients. Further outcome studies with larger sample sizes are required to confirm these findings.

Dexmedetomidine preconditioning for myocardial protection in ischaemia-reperfusion injury in rats by downregulation of the high mobility group box 1-toll-like receptor 4-nuclear factor κB signalling pathway.

Pharmacological preconditioning reduces myocardial infarct size in ischaemia-reperfusion (I-R) injury. Dexmedetomidine, a selective α2 -adrenoceptor agonist, has a proven cardioprotective effect when administered prior to I-R, although the underlying mechanisms for this effect are not fully understood. We evaluated whether dexmedetomidine preconditioning could induce a myocardio-protective effect against I-R injury by inhibiting associated inflammatory processes through downregulation of the high mobility group box 1 (HMGB1)-toll-like receptor 4 (TLR4)-nuclear factor κB (NF-κB) signalling pathway. Seventy rats were randomly assigned to seven groups: a control and six test groups, involving I-R for 30 and 120 minutes, respectively, in isolated rat hearts and different pretreatment protocols with dexmedetomidine (10 nmol/L) as well as yohimbine (1 µmol/L) and recombinant HMGB1 peptide (rHMGB1; 20 µg/L), alone or in combination with dexmedetomidine. Cardiac function was recorded; myocardial HMGB1, TLR4, and NF-κB activities and levels of tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were measured as were lactate dehydrogenase (LDH) and creatine kinase (CK) in coronary outflow. Dexmedetomidine preconditioning significantly improved cardiac function (P<.05), downregulated the expression of HMGB1-TLR4-NF-κB, reduced levels of TNF-α and IL-6 in isolated ventricles during I-R injury, and significantly reduced CK and LDH levels in coronary outflow (P<.05). All of these effects were partially reversed by yohimbine (P<.05) or rHMGB1 (P<.05). Dexmedetomidine preconditioning alleviated myocardial I-R injury in rats through inhibition of inflammatory processes associated with downregulation of the HMGB1-TLR4-NF-κB signalling pathway via activation at α2 -adrenergic receptors.

Upregulation of cystathionine-ß-synthetase expression contributes to inflammatory pain in rat temporomandibular joint.

BACKGROUND: Hydrogen sulfide (H2S), an endogenous gaseotransmitter/modulator, is becoming appreciated that it may be involved in a wide variety of processes including inflammation and nociception. However, the role for H2S in nociceptive processing in trigeminal ganglion (TG) neuron remains unknown. The aim of this study was designed to investigate whether endogenous H2S synthesizing enzyme cystathionine-ß-synthetase (CBS) plays a role in inflammatory pain in temporomandibular joint (TMJ). METHODS: TMJ inflammatory pain was induced by injection of complete Freund's adjuvant (CFA) into TMJ of adult male rats. Von Frey filaments were used to examine pain behavioral responses in rats following injection of CFA or normal saline (NS). Whole cell patch clamp recordings were employed on acutely isolated TG neurons from rats 2 days after CFA injection. Western blot analysis was carried out to measure protein expression in TGs. RESULTS: Injection of CFA into TMJ produced a time dependent hyperalgesia as evidenced by reduced escape threshold in rats responding to VFF stimulation. The reduced escape threshold was partially reversed by injection of O-(Carboxymethyl) hydroxylamine hemihydrochloride (AOAA), an inhibitor for CBS, in a dose-dependent manner. CFA injection led to a marked upregulation of CBS expression when compared with age-matched controls. CFA injection enhanced neuronal excitability as evidenced by depolarization of resting membrane potentials, reduction in rheobase, and an increase in number of action potentials evoked by 2 and 3 times rheobase current stimulation and by a ramp current stimulation of TG neurons innervating the TMJ area. CFA injection also led to a reduction of IK but not IA current density of TG neurons. Application of AOAA in TMJ area reduced the production of H2S in TGs and reversed the enhanced neural hyperexcitability and increased the IK currents of TG neurons. CONCLUSION: These data together with our previous report indicate that endogenous H2S generating enzyme CBS plays an important role in TMJ inflammation, which is likely mediated by inhibition of IK currents, thus identifying a specific molecular mechanism underlying pain and sensitization in TMJ inflammation.

Advances in Developing Small Molecule Drugs for Alzheimer's Disease.

Alzheimer's disease (AD) is the most common type of dementia among middle-aged and elderly individuals. Accelerating the prevention and treatment of AD has become an urgent problem. New technology including Computer-aided drug design (CADD) can effectively reduce the medication cost for patients with AD, reduce the cost of living, and improve the quality of life of patients, providing new ideas for treating AD. This paper reviews the pathogenesis of AD, the latest developments in CADD and other small-molecule docking technologies for drug discovery and development; the current research status of small-molecule compounds for AD at home and abroad from the perspective of drug action targets; and the development trend of new drug development for AD in the future.

Triggering Receptor Expressed on Myeloid Cells 2 Alleviated Sevoflurane-Induced Developmental Neurotoxicity via Microglial Pruning of Dendritic Spines in the CA1 Region of the Hippocampus.

Sevoflurane induces developmental neurotoxicity in mice; however, the underlying mechanisms remain unclear. Triggering receptor expressed on myeloid cells 2 (TREM2) is essential for microglia-mediated synaptic refinement during the early stages of brain development. We explored the effects of TREM2 on dendritic spine pruning during sevoflurane-induced developmental neurotoxicity in mice. Mice were anaesthetized with sevoflurane on postnatal days 6, 8, and 10. Behavioral performance was assessed using the open field test and Morris water maze test. Genetic knockdown of TREM2 and overexpression of TREM2 by stereotaxic injection were used for mechanistic experiments. Western blotting, immunofluorescence, electron microscopy, three-dimensional reconstruction, Golgi staining, and whole-cell patch-clamp recordings were performed. Sevoflurane exposures upregulated the protein expression of TREM2, increased microglia-mediated pruning of dendritic spines, and reduced synaptic multiplicity and excitability of CA1 neurons. TREM2 genetic knockdown significantly decreased dendritic spine pruning, and partially aggravated neuronal morphological abnormalities and cognitive impairments in sevoflurane-treated mice. In contrast, TREM2 overexpression enhanced microglia-mediated pruning of dendritic spines and rescued neuronal morphological abnormalities and cognitive dysfunction. TREM2 exerts a protective role against neurocognitive impairments in mice after neonatal exposures to sevoflurane by enhancing microglia-mediated pruning of dendritic spines in CA1 neurons. This provides a potential therapeutic target in the prevention of sevoflurane-induced developmental neurotoxicity.

Boosting Microglial Lipid Metabolism via TREM2 Signaling by Biomimetic Nanoparticles to Attenuate the Sevoflurane-Induced Developmental Neurotoxicity.

Lipid metabolism has been considered as a potential therapeutic target in sevoflurane-induced neurotoxicity that can potentially affect the learning and memory function in the developmental brain. Recently, triggering receptor expressed on myeloid cells 2 (TREM2) is identified as a crucial step in regulating lipid metabolism and associated with the pathogenesis of neurodegenerative diseases. Herein, it is reported that quercetin modified Cu2- x Se (abbreviated as CSPQ) nanoparticles can ameliorate sevoflurane-induced neurotoxicity by tuning the microglial lipid metabolism and promoting microglial M2-like polarization via TREM2 signaling pathway, in which the apolipoprotein E (ApoE), and adenosine triphosphate-binding cassette transporters (ABCA1 and ABCG1) levels are upregulated. Furthermore, the protective effects of CSPQ nanoparticles against sevoflurane-induced neurotoxicity via TREM2 are further demonstrated by the small interfering RNA (siRNA)-TREM2 transfected BV2 cells, which are obviously not influenced by CSPQ nanoparticles. The cell membrane coated CSPQ (referred as CSPQ@CM) nanoparticles can significantly reduce sevoflurane-induced learning and memory deficits, improve lipid metabolism dysfunction, and promote the remyelination in the hippocampus of mice. The study shows great potential of targeting microglial lipid metabolism in promoting remyelination of neurons for treatment of neurotoxicity and neurodegenerative diseases.

Complement C1q-mediated microglial synaptic elimination by enhancing desialylation underlies sevoflurane-induced developmental neurotoxicity.

BACKGROUND: Repeated neonatal sevoflurane exposures led to neurocognitive disorders in young mice. We aimed to assess the role of microglia and complement C1q in sevoflurane-induced neurotoxicity and explore the underlying mechanisms. METHODS: Neonatal mice were treated with sevoflurane on postnatal days 6, 8, and 10, and the Morris water maze was performed to assess cognitive functions. For mechanistic explorations, mice were treated with minocycline, C1q-antibody ANX005, and sialidase-inhibitor N-acetyl-2,3-dehydro-2-deoxyneuraminic acid (NADNA) before sevoflurane exposures. Western blotting, RT-qPCR, Golgi staining, 3D reconstruction and engulfment analysis, immunofluorescence, and microglial morphology analysis were performed. In vitro experiments were conducted in microglial cell line BV2 cells. RESULTS: Repeated neonatal sevoflurane exposures resulted in deficiencies in learning and cognition of young mice, accompanied by microglial activation and synapse loss. Sevoflurane enhanced microglia-mediated synapse elimination through C1q binding to synapses. Inhibition of microglial activation and phagocytosis with minocycline significantly reduced the loss of synapses. We further revealed the involvement of neuronal sialic acids in this process. The enhanced activity of sialidase by sevoflurane led to the loss of sialic acids, which facilitated C1q binding to synapses. Inhibition of C1q with ANX005 or inhibition of sialidase with NADNA significantly rescued microglia-mediated synapse loss and improved neurocognitive function. Sevoflurane enhanced the engulfment of BV2 cells, which was reversed by ANX005. CONCLUSIONS: Our findings demonstrated that C1q-mediated microglial synaptic elimination by enhancing desialylation contributed to sevoflurane-induced developmental neurotoxicity. Inhibition of C1q or sialidase may be a potential therapeutic strategy for this neurotoxicity.

In silico and in vitro analyses of a novel FoxO1 agonist reducing Aß levels via downregulation of BACE1.

AIMS: FoxO1 is an important target in the treatment of Alzheimer's disease (AD). However, FoxO1-specific agonists and their effects on AD have not yet been reported. This study aimed to identify small molecules that upregulate the activity of FoxO1 to attenuate the symptoms of AD. METHODS: FoxO1 agonists were identified by in silico screening and molecular dynamics simulation. Western blotting and reverse transcription-quantitative polymerase chain reaction assays were used to assess protein and gene expression levels of P21, BIM, and PPARγ downstream of FoxO1 in SH-SY5Y cells, respectively. Western blotting and enzyme-linked immunoassays were performed to explore the effect of FoxO1 agonists on APP metabolism. RESULTS: N-(3-methylisothiazol-5-yl)-2-(2-oxobenzo[d]oxazol-3(2H)-yl) acetamide (compound D) had the highest affinity for FoxO1. Compound D activated FoxO1 and regulated the expression of its downstream target genes, P21, BIM, and PPARγ. In SH-SY5Y cells treated with compound D, BACE1 expression levels were downregulated, and the levels of Aß1-40 and Aß1-42 were also reduced. CONCLUSIONS: We present a novel small-molecule FoxO1 agonist with good anti-AD effects. This study highlights a promising strategy for new drug discovery for AD.

Hydrogen sulfide increases excitability through suppression of sustained potassium channel currents of rat trigeminal ganglion neurons.

BACKGROUND: Hydrogen sulfide (H2S), an endogenous gaseotransmitter/modulator, is becoming appreciated that it may be involved in a wide variety of processes including inflammation and nociception. However, the role and mechanism for H2S in nociceptive processing in trigeminal ganglion (TG) neuron remains unknown. The aim of this study is to investigate distribution of endogenous H2S synthesizing enzyme cystathionine-ß-synthetase (CBS) expression and role of H2S on excitability and voltage-gated potassium channels of TG neurons. METHODS: Immunofluorescence studies were carried out to determine whether CBS was co-expressed in Kv1.1 or Kv1.4-positive TG neurons. Whole cell patch clamp recordings were employed on acutely isolated TG neurons from adult male Sprague Dawley rats (6-8 week old). von Frey filaments were used to examine the pain behavioral responses in rats following injection of sodium hydrosulfide. RESULTS: In rat TG, 77.3±6.6% neurons were immunoreactive for CBS, 85.1±3.8% for Kv1.1 and 97.8±1.1% for Kv1.4. Double staining showed that all CBS labeled cells were Kv1.1 and Kv1.4 positive, but only 92.2±6.1% of Kv1.1 and 78.2±9.9% of Kv1.4 positive cells contained CBS. Application of H2S donor NaHS (250 µM) led to a significant depolarization of resting membrane potential recorded from TG neurons. NaHS application also resulted in a dramatic reduction in rheobase, hyperpolarization of action potential threshold, and a significant increase in the number of action potentials evoked at 2X and 3X rheobase stimulation. Under voltage-clamp conditions, TG neurons exhibited transient A-type (IA) and sustained outward rectifier K+ currents (IK). Application of NaHS did suppress IK density while did not change IA density of TG neurons (n=6). Furthermore, NaHS, a donor of hydrogen sulfide, produced a significant reduction in escape threshold in a dose dependent manner. CONCLUSION: These data suggest that endogenous H2S generating enzyme CBS was co-localized well with Kv1.1 and Kv1.4 in TG neurons and that H2S produces the mechanic pain and increases neuronal excitability, which might be largely mediated by suppressing IK density, thus identifying for the first time a specific molecular mechanism underlying pain and sensitization in TG.