Nucleoporin Seh1 controls murine neocortical development via transcriptional repression of p21 in neural stem cells.

Mutations or dysregulation of nucleoporins (Nups) are strongly associated with neural developmental diseases, yet the underlying mechanisms remain poorly understood. Here, we show that depletion of Nup Seh1 in radial glial progenitors results in defective neural progenitor proliferation and differentiation that ultimately manifests in impaired neurogenesis and microcephaly. This loss of stem cell proliferation is not associated with defects in the nucleocytoplasmic transport. Rather, transcriptome analysis showed that ablation of Seh1 in neural stem cells derepresses the expression of p21, and knockdown of p21 partially restored self-renewal capacity. Mechanistically, Seh1 cooperates with the NuRD transcription repressor complex at the nuclear periphery to regulate p21 expression. Together, these findings identified that Nups regulate brain development by exerting a chromatin-associated role and affecting neural stem cell proliferation.

Corrigendum: Interferon-induced transmembrane protein 3 in the hippocampus: a potential novel target for the therapeutic effects of recombinant human brain natriuretic peptide on sepsis-associated encephalopathy.

[This corrects the article DOI: 10.3389/fnmol.2023.1182005.].

Interferon-induced transmembrane protein 3 in the hippocampus: a potential novel target for the therapeutic effects of recombinant human brain natriuretic peptide on sepsis-associated encephalopathy.

Objective: This study aims to explore whether interferon-induced transmembrane protein 3 (IFITM3) is involved in recombinant human brain natriuretic peptide (rhBNP)-mediated effects on sepsis-induced cognitive dysfunction in mice. Methods: The cellular localization and expression level of IFITM3 in the hippocampus were detected. The IFITM3 overexpression was achieved using an intracranial stereotactic system to inject an adeno-associated virus into the hippocampal CA1 region of mice. Field experiments, an elevated plus maze, and conditioned fear memory tests assessed the cognitive impairment in rhBNP-treated septic mice. Finally, in the hippocampus of septic mice, terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) staining and Immunoblot were used to detect changes in the protein expression of cleaved Caspase-8 and cleaved Caspase-3 in apoptosis-related pathways, and toll-like receptor 4 (TLR4) and nuclear factor κB (NF-κB) p65 in inflammatory pathways. Results: Fourteen days after cecal ligation and puncture (CLP) surgery, IFITM3 localized in the plasma membrane and cytoplasm of the astrocytes in the hippocampus of septic mice, partially attached to the perivascular and neuronal surfaces, but not expressed in the microglia. The expression of IFITM3 was increased in the astrocytes and neurons in the hippocampus of septic mice, which was selectively inhibited by the administration of rhBNP. Overexpression of IFITM3 resulted in elevated anxiety levels and long-term learning and memory dysfunction, completely abolished the therapeutic effect of rhBNP on cognitive impairment in septic mice, and induced an increase in the number of neuronal apoptosis in the hippocampal CA1 region. The expression levels of cleaved Caspase-3 and cleaved Caspase-8 proteins were significantly increased in the hippocampus, but the expression levels of TLR4 and NF-κB p65 were not increased. Conclusion: The activation of IFITM3 may be a potential new target for treating sepsis-associated encephalopathy (SAE), and it may be one of the key anti-apoptotic mechanisms in rhBNP exerting its therapeutic effect, providing new insight into the clinical treatment of SAE patients.

Activation of endogenous retrovirus triggers microglial immuno-inflammation and contributes to negative emotional behaviors in mice with chronic stress.

BACKGROUND: The "missing" link of complex and multifaceted interplay among endogenous retroviruses (ERVs) transcription, chronic immuno-inflammation, and the development of psychiatric disorders is still far from being completely clarified. The present study was aimed to investigate the mechanism of protective role of inhibiting ERVs on reversing microglial immuno-inflammation in basolateral amygdala (BLA) in chronic stress-induced negative emotional behaviors in mice. METHODS: Male C57BL/6 mice were exposed to chronic unpredictable mild stress (CUMS) for 6 w. Negative emotional behaviors were comprehensively investigated to identify the susceptible mice. Microglial morphology, ERVs transcription, intrinsic nucleic acids sensing response, and immuno-inflammation in BLA were assessed. RESULTS: Mice with chronic stress were presented as obviously depressive- and anxiety-like behaviors, and accompanied with significant microglial morphological activation, murine ERVs genes MuERV-L, MusD, and IAP transcription, cGAS-IFI16-STING pathway activation, NF-κB signaling pathway priming, as well as NLRP3 inflammasome activation in BLA. Antiretroviral therapy, pharmacological inhibition of reverse transcriptases, as well as knocking-down the ERVs transcriptional regulation gene p53 significantly inhibited microglial ERVs transcription and immuno-inflammation in BLA, as well as improved the chronic stress-induced negative emotional behaviors. CONCLUSIONS: Our results provided an innovative therapeutic approach that targeting ERVs-associated microglial immuno-inflammation may be beneficial to the patients with psychotic disorders.

Microglial Piezo1 senses Aß fibril stiffness to restrict Alzheimer's disease.

The pathology of Alzheimer's disease (AD) is featured with extracellular amyloid-ß (Aß) plaques, whose impact on the mechanical properties of the surrounding brain tissues is unclear. Microglia sense and integrate biochemical cues of the microenvironment. However, whether the microglial mechanosensing pathways influence AD pathogenesis is unknown. Here, we surveyed the elevated stiffness of Aß-plaque-associated tissues and observed the selective upregulation of the mechanosensitive ion channel Piezo1 in Aß-plaque-associated microglia. Piezo1 sensed the stiffness stimuli of Aß fibrils and subsequently induced Ca2+ influx for microglial clustering, phagocytosis, and compacting of Aß plaques. Microglia lacking Piezo1 led to the exacerbation of Aß pathology and cognitive decline, whereas pharmacological activation of microglial Piezo1 ameliorated brain Aß burden and cognitive impairment in 5 × FAD mice. Together, our results reveal that Piezo1, a mechanosensor of Aß fibril stiffness in microglia, represents a potential therapeutic target for AD.

Involvement of Paired Immunoglobulin-Like Receptor B in Cognitive Dysfunction Through Hippocampal-Dependent Synaptic Plasticity Impairments in Mice Subjected to Chronic Sleep Restriction.

Sleep loss is often associated with cognitive dysfunction. Alterations in the structure and function of synapses in the hippocampus are thought to underlie memory storage. Paired immunoglobulin-like receptor B (PirB) plays a negative role in various neurological diseases by inhibiting axon regeneration and synaptic plasticity. However, the contributions of PirB to the mechanisms underlying the changes in synaptic plasticity after sleep loss that ultimately promote deficits in cognitive function have not been well elucidated. Here, we showed that chronic sleep restriction (CSR) mice displayed cognitive impairment and synaptic deficits accompanied by upregulation of PirB expression in the hippocampus. Mechanistically, PirB caused the dysregulation of actin through the RhoA/ROCK2/LIMK1/cofilin signalling pathway, leading to abnormal structural and functional plasticity, which in turn resulted in cognitive dysfunction. PirB knockdown alleviated synaptic deficits and cognitive impairment after CSR by inhibiting the RhoA/ROCK2/LIMK1/cofilin signalling pathway. Moreover, we found that fasudil, a widely used ROCK2 inhibitor, could mimic the beneficial effect of PirB knockdown and ameliorate synaptic deficits and cognitive impairment, further demonstrating that PirB induced cognitive dysfunction after CSR via the RhoA/ROCK2/LIMK1/cofilin signalling pathway. Our study sheds new light on the role of PirB as an important mediator in modulating the dysfunction of synaptic plasticity and cognitive function via the RhoA/ROCK2/LIMK1/cofilin signalling pathway, which indicated that hippocampal PirB is a promising therapeutic target for counteracting cognitive impairment after CSR. This illustration depicts the signalling pathway by PirB in mediating cognitive impairment and synaptic deficits in CSR mice. In the hippocampus of CSR mice, the expression level of PirB was significantly increased. In addition, CSR increases RhoA and ROCK2 levels and reduces levels of both LIMK1 and cofilin phosphorylation. PirB knockdown reverses cognitive impairment and synaptic plasticity disorders caused by CSR through the RhoA/ROCK2/LIMK1/cofilin signalling pathway.

Neuronal-microglial liver X receptor ß activating decrease neuroinflammation and chronic stress-induced depression-related behavior in mice.

Depression is accompanied by excessive neuroinflammation. Liver X receptor ß (LXRß) has been reported as a newly emerging target that exerts systemic and organic inflammation modulation. However, the modulatory mechanism in alleviating neuroinflammation are far from being revealed. In the current study, depression-related behaviors in mice were induced by chronic unpredictable mild stress (CUMS) and corticosterone (CORT) drinking. Mice received either TO901317, PLX-5622 and intra- bilateral basolateral amygdale (BLA) injection of rAAV9-hSyn-hM3D(Gq)-eGFP to activate LXRß, eliminate microglia and pharmacogenetic activate neurons in BLA, respectively, followed by behavioral tests. Microglial pro-inflammatory and pro-phagocytic activation, as well as nuclear factor-κB (NF-κB) signaling pathway, NLRP3 inflammasome activation and interleukin-1ß (IL-1ß) release in BLA were investigated. Moreover, pro-inflammatory activation of BV2 cells-induced by CORT with or without TO901317 was detected. Neuroinflammation indicated by IL-1ß release was measured in a co-culture system of HT22-primary microglia with or without TO901317. Our results indicated that chronic stress induced depression-related behaviors, which were accompanied with microglial pro-inflammatory and pro-phagocytic activation, as well as NF-κB signaling pathway and NLRP3 inflammasome activation in BLA. Accordingly, pharmacological activation of LXRß inhibited microglial pro-inflammatory and pro-phagocytic activation, as well as NF-κB signaling pathway and NLRP3 inflammasome activation, and IL-1ß release both in vivo and in vitro. Finally, both elimination of microglia and pharmacogenetic activation of neurons in BLA protected mice from chronic stress-induced depression-related behavior. Collectively, pharmacological activation of neuronal-microglial LXRß alleviates depression-related behavior by modulating excessive neuroinflammation via inhibiting NF-κB signaling pathway and NLRP3 inflammasome activation.

Extracellular Nucleosomes Accelerate Microglial Inflammation via C-Type Lectin Receptor 2D and Toll-Like Receptor 9 in mPFC of Mice With Chronic Stress.

Damage-associated molecular patterns (DAMPs) are the primary promoter of progressive neuroinflammation and are associated with chronic stress-related emotional disorders. The present study investigated the role and mechanism of extracellular nucleosomes and histones, the newly defined DAMPs, in mice with chronic stress. C57BL/6 mice were exposed to chronic unpredictable mild stress (CUMS) and corticosterone drinking, respectively, for 4 weeks. Negative emotional behaviors were comprehensively investigated. Microglial morphology, oxidative stress, and inflammation, as well as C-type lectin receptor 2D (Clec2d) and Toll-like receptor 9 (TLR9) expression in medial prefrontal cortex (mPFC) were assessed with flow cytometer and cell sorting. Specifically, microglial pro-inflammatory activation and inflammation were further investigated with stereotactic injection of recombinant nucleosomes and histones in mPFC and further evaluated with AAV-Clec2d knocking-down, DNase I, and activated protein C (APC) pretreatment. Moreover, the rescue effect by AAV-Clec2d knocking-down was observed in mice with chronic stress. Mice with chronic stress were presented as obviously depressive- and anxiety-like behaviors and accompanied with significant microglial oxidative stress and inflammation, indicating by reactive oxygen species (ROS) production, primed nuclear factor-κB (NF-κB) signaling pathway, activated NACHT, LRR, and PYD domain-containing protein 3 (NLRP3) inflammasome, and upregulated Clec2d and TLR9 in mPFC, together with histones dictation in cerebrospinal fluid and extracellular trap formation. Stereotactic injection of nucleosomes was contributed to promote microglial inflammation rather than histones in mPFC, indicating that the pro-inflammatory role was derived from extracellular histones-bound DNA but not freely histones. AAV-Clec2d knocking-down, DNase I, and APC were all effective to inhibit nucleosome-induced microglial oxidative stress and inflammation. Moreover, AAV-Clec2d knocking-down in mice with chronic stress exhibited reduced microglial inflammation and improved negative emotional behaviors. Our findings reveal a novel mechanism of DAMP-associated inflammation that extracellular nucleosomes accelerate microglial inflammation via Clec2d and TLR9, and then contribute to chronic stress-induced emotional disorders.

Dexmedetomidine inhibits microglial activation through SNHG14/HMGB1 pathway in spinal cord ischemia-reperfusion injury mice.

OBJECTIVE: Microglial activation is an essential pathological mechanism of spinal cord ischemia-reperfusion injury (SCIRI). Previous studies showed dexmedetomidine (DEX) could alleviate SCIRI while the mechanism was not clear. This study aims to investigate the role of DEX in microglial activation and clarify the underlying mechanism. METHODS: The motion function of mice was quantified using the Basso Mouse Scale for Locomotion. The expression of long non-coding RNA (lncRNA) small nucleolar RNA host gene 14 (SNHG14) was determined by qRT-PCR. The expression of high-mobility group box 1 (HMGB1) was measured by western blot. The activation of microglia was evaluated by the expression of ED-1 and the levels of TNF-α and IL-6. The interplay between SNHG14 and HMGB1 was confirmed with RNA pull-down and RIP assay. The stability of HMGB1 was measured by ubiquitination assay and cycloheximide-chase assay. RESULTS: DEX inhibited microglial activation and down-regulated SNHG14 expression in SCIRI mice and oxygen and glucose deprivation/reoxygenation (OGD/R)-treated primary microglia. Functionally, SNHG14 overexpression reversed the inhibitory effect of DEX on OGD/R-induced microglial activation. Further investigation confirmed that SNHG14 bound to HMGB1, positively regulated HMGB1 expression by enhancing its stability. In addition, the silence of HMGB1 eliminated the pro-activation impact of SNHG14 overexpression on DEX-treated microglia under the OGD/R condition. Finally, in vivo experiments showed SNHG14 overexpression abrogated the therapeutic effect of DEX on SCIRI mice by up-regulating HMGB1. CONCLUSION: DEX accelerated HMGB1 degradation via down-regulating SNHG14, thus inhibiting microglial activation in SCIRI mice.

Study protocol for a randomised controlled clinical trial comparing desflurane-based versus propofol-based anaesthesia on postanaesthesia respiratory depression in patients with obstructive sleep apnoea after major abdominal surgery.

INTRODUCTION: Patients with obstructive sleep apnoea (OSA) are more sensitive to postanaesthesia respiratory depression. Whether different anaesthetic regimens (intravenous-based or inhalational-based general anaesthesia) affect the postanaesthesia respiratory depression is controversial. Although desflurane has been reported that presents favourable rapid recovery profile in special patients including whom with OSA, the strong clinical evidence of the benefit on postanaesthesia respiratory depression is far from being revealed. This study aims to fill this knowledge gap by investigating the postanaesthesia respiratory depression in postanaesthesia care unit (PACU) in patients with OSA after major abdominal surgery, followed by desflurane-based anaesthesia compared with propofol-based anaesthesia. METHODS AND ANALYSIS: Eight hundred and fifty-four patients with OSA scheduled for elective major abdominal surgery will be randomly 1:1 assigned to desflurane-based (n=427) or propofol-based anaesthesia (n=427) using a computer-generated randomisation scheme with permuted block size maintained by a centralised randomisation centre. Patients will be assessed before and a consecutive 3 days after their surgery according to the standardised tasks. Demographic data as well as surgical and anaesthesia information will be collected for the duration of the procedure. Incidence of postanaesthesia respiratory depression in PACU as well as anaesthesia recovery, emergence delirium, postoperative nausea and vomiting, rescue analgesia, duration of PACU and hospital stay, and any other adverse events will be assessed at the given study time point. Investigators performing postoperative follow-up are not involved in both anaesthesia implementation and postoperative care. ETHICS AND DISSEMINATION: This study protocol has been approved by the ethics board at Xiang'an Hospital of Xiamen University (XAHLL2019003). The results of this study will be published in a peer-review journal and presented at national conferences as poster or oral presentations. Participants wishing to know the results of this study will be contacted directly on data publication. TRIAL REGISTRATION NUMBER: ChiCTR2000031087.

Neuroprotective effect of ketamine against TNF-α-induced necroptosis in hippocampal neurons.

Tumour necrosis factor-α (TNF-α), a crucial cytokine, has various homeostatic and pathogenic bioactivities. The aim of this study was to assess the neuroprotective effect of ketamine against TNF-α-induced motor dysfunction and neuronal necroptosis in male C57BL/6J mice in vivo and HT-22 cell lines in vitro. The behavioural testing results of the present study indicate that ketamine ameliorated TNF-α-induced neurological dysfunction. Moreover, immunohistochemical staining results showed that TNF-α-induced brain dysfunction was caused by necroptosis and microglial activation, which could be attenuated by ketamine pre-treatment inhibiting reactive oxygen species production and mixed lineage kinase domain-like phosphorylation in hippocampal neurons. Therefore, we concluded that ketamine may have neuroprotective effects as a potent inhibitor of necroptosis, which provides a new theoretical and experimental basis for the application of ketamine in TNF-α-induced necroptosis-associated diseases.

A subanesthetic dose of sevoflurane combined with oxygen exerts bactericidal effects and prevents lung injury through the nitric oxide pathway during sepsis.

Volatile anesthetics have been proven to treat experimental sepsis. Sevoflurane combined with oxygen is widely applied in the clinic, and our previous study indicated that this regimen significantly reduced sepsis-induced inflammatory responses and that inhibition of NF-κB pathway activation may contribute to this protection effect. Furthermore, our previous data has shown that sevoflurane combined with oxygen has prevention effect on sepsis-induced lung injury properties and bactericidal properties, but the mechanism is not well understood. Nitric oxide (NO) has been shown to have bactericidal effects and mitigating effects on lung injury, but this is not well studied in sepsis. The present study suggested that in cecal ligation and puncture (CLP)-induced sepsis, sevoflurane combined with oxygen had bactericidal effects and reduced neutrophil infiltration into the lung, preventing inflammatory lung injury. NO production was significantly induced in peritoneal lavage fluid and bronchoalveolar lavage fluid. These effects were abolished by pharmacological inhibition of nitric oxide synthase activity. Thus, our findings suggest that sevoflurane combined with oxygen exerts bactericidal effects and prevents lung injury in sepsis through the NO pathway.

Therapeutic effects of recombinant human brain natriuretic peptide on sepsis-associated encephalopathy in mice.

There is little information in the sepsis treatment guidelines on the prevention and treatment of cognitive dysfunction after sepsis. This study aimed to explore whether Recombinant human brain natriuretic peptide (rhBNP) has protective effects against sepsis-associated encephalopathy (SAE) in a mouse model. The results showed that 50 µg/kg of rhBNP significantly improved the 14-day survival of cecal ligation and puncture (CLP)-induced septic mice and mitigated cognitive dysfunction and anxiety. Fourteen days after CLP surgery, septic mice showed increased BBB permeability and neuronal apoptosis. rhBNP treatment significantly reduced pathological changes in the brain of CLP mice. Meanwhile, rhBNP therapy also reduced the level of inflammatory cytokines in the hippocampus, possibly via inhibiting the TLR4-NF-κB pathway. These results indicate that rhBNP may be a promising drug for the treatment of SAE.

Minocycline promotes cardiomyocyte mitochondrial autophagy and cardiomyocyte autophagy to prevent sepsis-induced cardiac dysfunction by Akt/mTOR signaling.

Myocardial damage is responsible for the high mortality of sepsis. However, the underlying mechanism is not well understood. Cardiomyocyte autophagy alleviates the cardiac injury caused by myocardial infarction. Enhanced cardiomyocyte autophagy also has protective effects against cardiomyocyte mitochondrial injury. Minocycline enhances autophagy in many types of cells under different types of pathological stress and can be easily taken up by cardiomyocytes. The present study investigated whether minocycline prevented myocardial injury caused by sepsis and whether cardiomyocyte autophagy participated in this process. The results indicated that minocycline enhanced cardiomyocyte mitochondrial autophagy and cardiomyocyte autophagy and improved myocardial mitochondrial and cardiac function. Minocycline upregulated protein kinase B (Akt) phosphorylation, inhibited mTORC1 expression and enhanced mTORC2 expression. In conclusion, minocycline enhanced cardiomyocyte mitochondrial autophagy and cardiomyocyte autophagy and improved cardiac function. The underlying mechanisms were associated with mTORC1 inhibition and mTORC2 activation. Thus, our findings suggest that minocycline may represent a potential approach for treating myocardial injury and provide novel insights into the underlying mechanisms of myocardial injury and dysfunction after sepsis.

Liver X receptor ß in the hippocampus: A potential novel target for the treatment of major depressive disorder?

Liver X receptors (LXRs), including LXRα and LXRß isoforms, have been implicated in multiple physiological functions including promoting neurogenesis, improving synaptic plasticity, preventing neurodegeneration, inhibiting inflammation as well as regulating cholesterol metabolism. However, a potential role of LXRs in the treatment of major depressive disorder (MDD) has never been investigated previously. Our present results demonstrated that levels of hippocampal LXRß but not LXRα were down-regulated in rats exposed to chronic unpredictable stress (CUS) and were negatively correlated with the severity of CUS-induced depressive-like behaviors. Furthermore, rats with LXRß knockdown by short hairpin RNA (shRNA) in hippocampus displayed depressive-like behaviors and impaired hippocampal neurogenesis similar to those observed after CUS exposure. Conversely, LXRs activation by GW3965 (GW), a synthetic dual agonist for both LXRα and LXRß isoforms, could improve depression-like behaviors and reverse the impaired hippocampal neurogenesis in rats exposed to CUS. LXRß knockdown by shRNA completely abrogated the antidepressant and hippocampal neurogenesis-promoting effects of GW, suggesting that LXRß isoform mediated the antidepressant and hippocampal neurogenesis-promoting effects of the LXRα/ß dual agonist. However, ablation of hippocampal neurogenesis with x-irradiation only partly but not completely abolished the antidepressant effects of GW in the behavioral tests, implying that the antidepressant effects mediated by LXRß isoform are likely through both neurogenesis-dependent and -independent pathways. Thus, our findings suggest that LXRß activation may represent a potential novel target for the treatment of MDD and also provide a novel insight into the underlying mechanisms of MDD.

TAT-Ngn2 Enhances Cognitive Function Recovery and Regulates Caspase-Dependent and Mitochondrial Apoptotic Pathways After Experimental Stroke.

Neurogenin-2 (Ngn2) is a basic helix-loop-helix (bHLH) transcription factor that contributes to the identification and specification of neuronal fate during neurogenesis. In our previous study, we found that Ngn2 plays an important role in alleviating neuronal apoptosis, which may be viewed as an attractive candidate target for the treatment of cerebral ischemia. However, novel strategies require an understanding of the function and mechanism of Ngn2 in mature hippocampal neurons after global cerebral ischemic injury. Here, we found that the expression of Ngn2 decreased in the hippocampus after global cerebral ischemic injury in mice and in primary hippocampal neurons after oxygen glucose deprivation (OGD) injury. Then, transactivator of transcription (TAT)-Ngn2, which was constructed by fusing a TAT domain to Ngn2, was effectively transported and incorporated into hippocampal neurons after intraperitoneal (i.p.) injection and enhanced cognitive functional recovery in the acute stage after reperfusion. Furthermore, TAT-Ngn2 alleviated hippocampal neuronal damage and apoptosis, and inhibited the cytochrome C (CytC) leak from the mitochondria to the cytoplasm through regulating the expression levels of brain-derived neurotrophic factor (BDNF), phosphorylation tropomyosin-related kinase B (pTrkB), Bcl-2, Bax and cleaved caspase-3 after reperfusion injury in vivo and in vitro. These findings suggest that the downregulation of Ngn2 expression may have an important role in triggering brain injury after ischemic stroke and that the neuroprotection of TAT-Ngn2 against stroke might involve the modulation of BDNF-TrkB signaling that regulates caspase-dependent and mitochondrial apoptotic pathways, which may be an attractive therapeutic strategy for cerebral ischemic injury.

Combined administration of a sedative dose sevoflurane and 60% oxygen reduces inflammatory responses to sepsis in animals and in human PMBCs.

Our study aims to investigate the effects of the inhalation of subanesthestic doses of sevoflurane combined with oxygen on sepsis. Male Sprague-Dawley rats or Male ICR/Km mice underwent caecal ligation and puncture (CLP) or intraperitoneal injection of lipopolysccharide (LPS) to induce sepsis, while sham rats were used as control. Then, rats were treated with the inhalation of sevoflurane in oxygen; and air or 100% oxygen was used as control. Seven-day survival, lung injury and inflammatory factors were assessed. In this in vitro experiment, we obtained RAW264.7 macrophages and human peripheral blood mononuclear cells (PBMCs) incubated by LPS or plasma from septic patients to explore the NF-κB pathway in the effect of the inhalation of sevoflurane combined with oxygen in sepsis. In this study, we found that the inhalation of 0.5 MAC of sevoflurane in 60% oxygen was the best protocol for protecting against lethality resulting from sepsis and ALI, and there was a time window for these protective effects. We also founded that 0.5 MAC of sevoflurane in 60% oxygen inhibited the nuclear translocation of NF-κB in human PBMCs induced by LPS or plasma from septic patients. The subanesthesia dose sevoflurane in 60% oxygen may reduce sepsis-induced inflammatory responses in animals and in PBMCs, and the inhibition to the activation of the NF-κB pathway may contribute to this protection.

Sub-anesthesia Dose of Isoflurane in 60% Oxygen Reduces Inflammatory Responses in Experimental Sepsis Models.

BACKGROUND: Sepsis is a major cause of mortality in Intensive Care Units. Anesthetic dose isoflurane and 100% oxygen were proved to be beneficial in sepsis; however, their application in septic patients is limited because long-term hyperoxia may induce oxygen toxicity and anesthetic dose isoflurane has potential adverse consequences. This study was scheduled to find the optimal combination of isoflurane and oxygen in protecting experimental sepsis and its mechanisms. METHODS: The effects of combined therapy with isoflurane and oxygen on lung injury and sepsis were determined in animal models of sepsis induced by cecal ligation and puncture (CLP) or intraperitoneal injection of lipopolysaccharide (LPS) or zymosan. Mouse RAW264.7 cells or human peripheral blood mononuclear cells (PBMCs) were treated by LPS to probe mechanisms. The nuclear factor kappa B (NF-κB) signaling molecules were examined by Western blot and cellular immunohistochemistry. RESULTS: The 0.5 minimum alveolar concentration (MAC) isoflurane in 60% oxygen was the best combination of oxygen and isoflurane for reducing mortality in experimental sepsis induced by CLP, intraperitoneal injection of LPS, or zymosan. The 0.5 MAC isoflurane in 60% oxygen inhibited proinflammatory cytokines in peritoneal lavage fluids (tumor necrosis factor-alpha [TNF-ß]: 149.3 vs. 229.7 pg/ml, interleukin [IL]-1ß: 12.5 vs. 20.6 pg/ml, IL-6: 86.1 vs. 116.1 pg/ml, and high-mobility group protein 1 [HMGB1]: 323.7 vs. 449.3 ng/ml; all P< 0.05) and serum (TNF-ß: 302.7 vs. 450.7 pg/ml, IL-1ß: 51.7 vs. 96.7 pg/ml, IL-6: 390.4 vs. 722.5 pg/ml, and HMGB1: 592.2 vs. 985.4 ng/ml; all P< 0.05) in septic animals. In vitro experiments showed that the 0.5 MAC isoflurane in 60% oxygen reduced inflammatory responses in mouse RAW264.7 cells, after LPS stimulation (all P< 0.05). Suppressed activation of NF-κB pathway was also observed in mouse RAW264.7 macrophages and human PBMCs after LPS stimulation or plasma from septic patients. The 0.5 MAC isoflurane in 60% oxygen also prevented the increases of phospho-IKKß/ß, phospho-IκBß, and phospho-p65 expressions in RAW264.7 macrophages after LPS stimulation (all P< 0.05). CONCLUSION: Combined administration of a sedative dose of isoflurane with 60% oxygen improves survival of septic animals through reducing inflammatory responses.

Polydatin protects cardiomyocytes against myocardial infarction injury by activating Sirt3.

Myocardial infarction (MI), which is characterized by chamber dilation and left ventricular (LV) dysfunction, represents a major cause of morbidity and mortality worldwide. Polydatin (PD), a monocrystalline and polyphenolic drug isolated from a traditional Chinese herb (Polygonum cuspidatum), alleviates mitochondrial dysfunction. We investigated the effects and underlying mechanisms of PD in post-MI cardiac dysfunction. We constructed an MI model by left anterior descending (LAD) coronary artery ligation using wild-type (WT) and Sirt3 knockout (Sirt3-/-) mice. Cardiac function, cardiomyocytes autophagy levels, apoptosis and mitochondria biogenesis in mice that underwent cardiac MI injury were compared between groups. PD significantly improved cardiac function, increased autophagy levels and decreased cardiomyocytes apoptosis after MI. Furthermore, PD improved mitochondrial biogenesis, which is evidenced by increased ATP content, citrate synthase (CS) activity and complexes I/II/III/IV/V activities in the cardiomyocytes subjected to MI injury. Interestingly, Sirt3 knockout abolished the protective effects of PD administration. PD inhibited apoptosis in cultured neonatal mouse ventricular myocytes subjected to hypoxia for 6h to simulate MI injury. PD increased GFP-LC3 puncta, and reduced the accumulation of protein aggresomes and p62 in cardiomyocytes after hypoxia. Interestingly, the knock-down of Sirt3 nullified the PD-induced beneficial effects. Thus, the protective effects of PD are associated with the up-regulation of autophagy and improvement of mitochondrial biogenesis through Sirt3 activity.

Notch signaling activation is critical to the development of neuropathic pain.

BACKGROUND: Nerve injury-induced neuropathic pain is a major health problem worldwide. Notch signaling is a highly conserved pathway in evolution, which has an important role in synaptic plasticity and inflammation in central nervous system. The present study was designed to investigate the potential role of notch signaling in the development of neuropathic pain. METHODS: The neuropathic pain was induced by spared nerve injury (SNI) in rats. The activation of notch signaling in the lumbar spinal dorsal horn was measured. DAPT, an inhibitor of notch signaling, was intrathecally (i.t.) administered before SNI or after appearance of pain sensitivity. Moreover, Jagged-1 (JAG-1) peptide, a ligand of notch signaling, was i.t. administered to normal rats. The mechanical allodynia was assessed by von Frey test. RESULTS: Here, we found that DAPT administered 0.5 h before SNI operation could significantly prevent the decrease of mechanical paw withdrawal threshold (PWT) for more than 4 weeks (P < 0.05 vs. SNI group). DAPT administered after appearance of pain sensitivity could also significantly reverse the decrease of mechanical PWT in a dose-dependent manner (P < 0.05). In addition, administration of Jagged-1 (JAG-1) peptide significantly decreased the mechanical PWT of normal rats in a dose-dependent manner (P < 0.05). CONCLUSIONS: Therefore, notch signaling activation might contribute to the development of neuropathic pain. This study might provide a new therapeutic target for neuropathic pain.