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.

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).

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.

Activation of CCL21-GPR174/CCR7 on cardiac fibroblasts underlies myocardial ischemia/reperfusion injury.

Background: The mechanisms underlying myocardial ischemia/reperfusion (I/R) injury are not fully understood. This study aims to explore key candidate genes and potential therapeutic targets for treatment of myocardial I/R injury. Methods: The transcriptional profiles of ventricular myocardium during cardiac arrest, ischemia, and reperfusion were obtained from the Gene Expression Omnibus database. Based on the transcriptional data of GSE6381, functional pathway and process enrichment analyses, protein-protein interaction network, and gene set enrichment analyses were conducted. In the animal experiments, we established the myocardial I/R injury model in mice. We validated the mRNA and protein expression of the key genes using the qPCR and western blots. We further assessed the expression and localization of CCL21 and its receptors using immunofluorescence staining experiments. Results: The microarray analyses identified five key genes (CCL21, XCR1, CXCL13, EDN1, and CASR). Myocardial I/R process in mice resulted in significant myocardial infraction, histological damage, and myocardial apoptosis. The results of qPCR and western blots showed that the expression of CCL21 and CXCL13 were increased following myocardial I/R injury in mice. Furthermore, the immunofluorescence staining results revealed that the expression of GPR174/CCR7 (CCL21 receptors), but not CXCR5 (CXCL13 receptor), was elevated following myocardial I/R injury. Moreover, the activated CCL21-GPR174/CCR7 signaling was located on the cardiac fibroblasts of the myocardium with I/R injury. Conclusion: This study revealed several key factors underlying myocardial I/R injury. Of these, the activation of CCL21-GPR174/CCR7 signaling on cardiac fibroblasts was highlighted, which provides potential therapeutic targets for cardioprotection.

Dexmedetomidine Attenuates Ferroptosis-Mediated Renal Ischemia/Reperfusion Injury and Inflammation by Inhibiting ACSL4 via α2-AR.

Ischemia-reperfusion (I/R) injury is a serious clinical pathology associated with acute kidney injury (AKI). Ferroptosis is non-apoptotic cell death that is known to contribute to renal I/R injury. Dexmedetomidine (Dex) has been shown to exert anti-inflammatory and organ protective effects. This study aimed to investigate the detailed molecular mechanism of Dex protects kidneys against I/R injury through inhibiting ferroptosis. We established the I/R-induced renal injury model in mice, and OGD/R induced HEK293T cells damage in vitro. RNA-seq analysis was performed for identifying the potential therapeutic targets. RNA-seq analysis for differentially expressed genes (DEGs) reported Acyl-CoA synthetase long-chain family member 4 (ACSL4) related to ferroptosis and inflammation in I/R mice renal, which was validated in rodent renal. Liproxstatin-1, the specific small-molecule inhibitor of ferroptosis, significantly attenuated ferroptosis-mediated renal I/R injury with decreased LPO, MDA, and LDH levels, and increased GSH level. Inhibiting the activity of ACSL4 by the Rosiglitazone (ROSI) resulted in the decreased ferroptosis and inflammation, as well as reduced renal tissue damage, with decreasing LPO, MDA and LDH level, increasing GSH level, reducing COX2 and increasing GPx4 protein expression, and suppressing the TNF-α mRNA and IL-6 mRNA levels. Dex as a α2-adrenergic receptor (α2-AR) agonist performed renal protective effects against I/R-induced injury. Our results also revealed that Dex administration mitigated tissue damage, inhibited ferroptosis, and downregulated inflammation response following renal I/R injury, which were associated with the suppression of ACSL4. In addition, ACSL4 overexpression abolishes Dex-mediated protective effects on OGD/R induced ferroptosis and inflammation in HEK293T cells, and promotion of ACSL4 expression by α2-AR inhibitor significantly reversed the effects on the protective role of Dex. This present study indicated that the Dex attenuates ferroptosis-mediated renal I/R injury and inflammation by inhibiting ACSL4 via α2-AR.

Effect of Perioperative Dexmedetomidine on Delayed Graft Function Following a Donation-After-Cardiac-Death Kidney Transplant: A Randomized Clinical Trial.

Importance: Delayed graft function (DGF) is a risk factor for acute rejection and graft failure after kidney transplant. Previous studies have suggested that dexmedetomidine may be renoprotective, but whether the use of dexmedetomidine would improve kidney allograft function is unknown. Objective: To investigate the effects of perioperative dexmedetomidine on DGF following a donation-after-cardiac-death (DCD) kidney transplant. Design, Setting, and Participants: This single-center, double-blind, placebo-controlled randomized clinical trial was conducted at The First Affiliated Hospital of Soochow University in Suzhou, China. Adults (18 years or older) who were scheduled for DCD kidney transplant were enrolled between September 1, 2019, and January 28, 2021, and then randomized to receive either dexmedetomidine or normal saline (placebo). One-year postoperative outcomes were recorded. All analyses were based on the modified intention-to-treat population. Interventions: Patients who were randomized to the dexmedetomidine group received a 24-hour perioperative dexmedetomidine intravenous infusion (0.4 µg/kg/h intraoperatively and 0.1 µg/kg/h postoperatively). Patients who were randomized to the normal saline group received an intravenous infusion of the placebo with the same dose regimen as the dexmedetomidine. Main Outcomes and Measures: The primary outcome was the incidence of DGF, defined as the need for dialysis in the first posttransplant week. The prespecified secondary outcomes were in-hospital repeated dialysis in the first posttransplant week, in-hospital acute rejection, and serum creatinine, serum cystatin C, estimated glomerular filtration rate, need for dialysis, and patient survival on posttransplant day 30. Results: Of the 114 patients enrolled, 111 completed the study (mean [SD] age, 43.4 [10.8] years; 64 male patients [57.7%]), of whom 56 were randomized to the dexmedetomidine group and 55 to the normal saline group. Dexmedetomidine infusion compared with normal saline reduced the incidence of DGF (17.9% vs 34.5%; odds ratio [OR], 0.41; 95% CI, 0.17-0.98; P = .04) and repeated dialysis (12.5% vs 30.9%; OR, 0.32; 95% CI, 0.13-0.88; P = .02, which was not statistically significant after multiple testing corrections), without significant effect on other secondary outcomes. Dexmedetomidine vs normal saline infusion led to a higher median (IQR) creatinine clearance rate on postoperative days 1 (9.9 [4.9-21.2] mL/min vs 7.9 [2.0-10.4] mL/min) and 2 (29.6 [9.7-67.4] mL/min vs 14.6 [3.8-45.1] mL/min) as well as increased median (IQR) urine output on postoperative days 2 (106.5 [66.3-175.6] mL/h vs 82.9 [27.1-141.9] mL/h) and 7 (126.1 [98.0-151.3] mL/h vs 107.0 [82.5-137.5] mL/h) and at hospital discharge discharge (110.4 [92.8-121.9] mL/h vs 97.1 [77.5-113.8] mL/h). Three patients (5.5%) from the normal saline group developed allograft failure by the post hoc 1-year follow-up visit. Conclusions and Relevance: This randomized clinical trial found that 24-hour perioperative dexmedetomidine decreased the incidence of DGF after DCD kidney transplant. The findings support the use of dexmedetomidine in kidney transplants. Trial Registration: Chinese Clinical Trial Registry Identifier: ChiCTR1900025493.

Exploring Potential Regulatory Anesthetic Drugs Based on RNA Binding Protein and Constructing CESC Prognosis Model: A Study Based on TCGA Database.

Objective: To investigate the differential expression of RBPs in cervical squamous cell carcinoma (CESC), analyze the regulatory effect of narcotic drugs on RBPs, and establish the prognostic risk model of CESC patients. Methods: RNA-SEQ data and clinical case data of cancer and normal samples from CESC patients were obtained from the Cancer Genome Atlas (TCGA) database and Genotype-Tissue Expression (GTEx) database. Differentially expressed RBPs were screened by R language and enriched. The CMAP database is used to predict the anesthetic drugs that regulate the differential expression of RBPs. The prognostic risk score model was constructed by COX regression analysis. Risk score of each CESC patient was calculated and divided into high-risk group and low-risk group according to the median risk score. The prediction efficiency of prognostic risk model was evaluated by Kaplan-Meier (KM) analysis and receiver operating characteristic (ROC) curve, and the correlation between prognostic risk model and clinical characteristics was analyzed. Immunohistochemistry was used to detect the expression of RNASEH2A and HENMT1 in tissues. Results: There were 65 differentially expressed RBPs in CESC. Five anesthetics, including benzocaine, procaine, pentoxyverine, and tetracaine were obtained to regulate RBPs. Survival analysis showed that seven genes were related to the prognosis of patients, and the CESC risk score model was constructed by COX regression. The risk score can be used as an independent prognostic factor. RNASEH2A and HENMT1 are up-regulated in tumors, which can effectively distinguish normal tissues from tumor tissues. Conclusion: It is found that different anesthetic drugs have different regulatory effects on the differential expression of RBPs. Based on the differentially expressed RBPs, the prognostic risk score model of CESC patients was constructed. To provide ideas for the formulation of individualized precise anesthesia scheme and cancer pain analgesia scheme, which is helpful to improve the perioperative survival rate of cancer patients.

Iguratimod Alleviates Myocardial Ischemia/Reperfusion Injury Through Inhibiting Inflammatory Response Induced by Cardiac Fibroblast Pyroptosis via COX2/NLRP3 Signaling Pathway.

Background: NLRP3 inflammasome contributes a lot to sterile inflammatory response and pyroptosis in ischemia/reperfusion (I/R) injury. Cardiac fibroblasts (CFs) are regarded as semi-professional inflammatory cells and they exert an immunomodulatory role in heart. Iguratimod provides a protective role in several human diseases through exerting a powerful anti-inflammatory effect. However, it is still unclear whether iguratimod could alleviate myocardial I/R injury and whether inflammation triggered by NLRP3-related pyroptosis of CFs is involved in this process. Methods: Transcriptomics analysis for GSE160516 dataset was conducted to explore the biological function of differentially expressed genes during myocardial I/R. In vivo, mice underwent ligation of left anterior descending coronary artery for 30 min followed by 24 h reperfusion. In vitro, primary CFs were subjected to hypoxia for 1 h followed by reoxygenation for 3 h (H/R). Iguratimod was used prior to I/R or H/R. Myocardial infarct area, serum level of cardiac troponin I (cTnI), pathology of myocardial tissue, cell viability, lactate dehydrogenase (LDH) release, and the expression levels of mRNA and protein for pyroptosis-related molecules were measured. Immunofluorescence was applied to determine the cellular localization of NLRP3 protein in cardiac tissue. Results: During myocardial I/R, inflammatory response was found to be the most significantly enriched biological process, and nucleotide-binding oligomerization domain (NOD)-like receptor signaling was a crucial pathway in mediating cardiac inflammation. In our experiments, pretreatment with iguratimod significantly ameliorated I/R-induced myocardial injury and H/R-induced pyroptosis of CFs, as evidenced by reduced myocardial infarct area, serum cTnI level, and LDH release in supernatants, as well as improved pathology of cardiac tissue and cell viability. Immunofluorescence analysis showed that NLRP3 was mainly localized in CFs. Moreover, iguratimod inhibited the expression of pro-inflammatory cytokines and pyroptosis-related molecules, including NLRP3, cleaved caspase-1, and GSDMD-N. Conclusion: Our results suggested that inflammatory response mediated by NOD-like receptor signaling is of vital importance in myocardial I/R injury. Iguratimod protected cardiomyocytes through reducing the cascade of inflammation in heart by inhibiting cardiac fibroblast pyroptosis via the COX2/NLRP3 signaling pathway.

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 Attenuates Ischemia/Reperfusion-Induced Myocardial Inflammation and Apoptosis Through Inhibiting Endoplasmic Reticulum Stress Signaling.

BACKGROUND: Endoplasmic reticulum stress (ERS)-mediated myocardial inflammation and apoptosis plays an important role in myocardial ischemia/reperfusion (I/R) injury. Dexmedetomidine has been used clinically with sedative, analgesic, and anti-inflammatory properties. This study aimed to determine the effects of dexmedetomidine pretreatment on inflammation, apoptosis, and the expression of ERS signaling during myocardial I/R injury. METHODS: Rats underwent myocardial ischemia for 30 min and reperfusion for 6 h, and H9c2 cardiomyocytes were subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) injury (OGD for 12 h and reoxygenation for 3 h). Dexmedetomidine was administered prior to myocardial ischemia in rats or ODG in cardiomyocytes. In addition, the α2-adrenergic receptor antagonist (yohimbine) or the PERK activator (CCT020312) was given prior to dexmedetomidine treatment. RESULTS: Dexmedetomidine pretreatment decreased serum levels of cardiac troponin I, reduced myocardial infarct size, alleviated histological structure damage, and improved left ventricular function following myocardial I/R injury in rats. In addition, dexmedetomidine pretreatment increased cell viability and reduced cytotoxicity following OGD/R injury in cardiomyocytes. Mechanistically, the cardioprotection offered by dexmedetomidine was mediated via the inhibition of inflammation and apoptosis through downregulating the expression of the ERS signaling pathway, including glucose-regulated protein 78 (GRP78), protein kinase R-like endoplasmic reticulum kinase (PERK), C/EBP homologous protein (CHOP), inositol-requiring protein 1 (IRE1), and activating transcription factor 6 (ATF6). Conversely, the protective effects of dexmedetomidine were diminished by blocking the α2 adrenergic receptors with yohimbine or promoting PERK phosphorylation with CCT020312. CONCLUSION: Dexmedetomidine pretreatment protects the hearts against I/R injury via inhibiting inflammation and apoptosis through downregulation of the ERS signaling pathway. Future clinical studies are needed to confirm the cardioprotective effects of dexmedetomidine in patients at risk of myocardial I/R injury.

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.

Platelet-rich plasma improves chronic inflammatory pain by inhibiting PKM2-mediated aerobic glycolysis in astrocytes.

BACKGROUND: Astrocytes are highly glycolytic cells that play a crucial role in chronic pain. Recently it has been found that inflammation and metabolism are related to the inflammatory stimuli closely that cause cellular metabolic changes. Pyruvate kinase M2 (PKM2) is a critical metabolic kinase in aerobic glycolysis or the Warburg effect. Besides, it also plays a crucial role in cell proliferation and signal transduction, but its role in astrocytes is still unclear. METHODS: The chronic inflammatory pain model was set up by intraplantar injection of complete Freund's adjuvant (CFA) in Sprague Dawley (SD) rats as well as the cell model was constructed by lipopolysaccharide-treated primary astrocytes. Von Frey filament stimulation was used to continuously observe the changes of pain behavior in rats after modeling. Then, immunofluorescence staining and Western blot tests were used to observe the expression levels of glial fibrillary acidic protein (GFAP), pyruvate kinase (PKM2), signal transducers and activators of transcription 3 (STAT3) and high mobility group box-1 protein (HMGB1). After that, specific kits measured lactate contents. Finally, we observed the platelet-rich plasma's (PRP) effect on mechanical hyperalgesia in rats with inflammatory pain induced by CFA and its effect on related signal molecules. RESULTS: We found that in the CFA-induced inflammatory pain model, astrocytes were significantly activated, GFAP was increased, PKM2 was significantly up-regulated, and the glycolytic product lactate was increased. Also, intrathecal injection of PRP increased the pain threshold, inhibited the activation of astrocytes, and decreased the expression of PKM2 and aerobic glycolysis; in LPS-activated primary astrocytes as an in vitro model, we found PKM2 translocation activationSTAT3 signaling resulted in sustained activation of astrocyte marker GFAP, and the expression level and localization of p-STAT3 were correlated with PKM2. PRP could inhibit the activation of astrocytes, reduce the expression of PKM2 and the expression levels of glycolysis and GFAP, GLUT1, and p-STAT3 in astrocytes. CONCLUSIONS: Our findings suggest PKM2 not only plays a glycolytic role in astrocytes, but also plays a crucial role in astrocyte-activated signaling pathways, and PRP attenuates CFA induced inflammatory pain by inhibiting aerobic glycolysis in astrocytes, providing a new therapeutic target for the treatment of inflammatory pain.

Periostin aggravates NLRP3 inflammasome-mediated pyroptosis in myocardial ischemia-reperfusion injury.

Pyroptosis is a form of caspase-1-induced programmed cell death. This study aimed to investigate the effect of periostin (postn) on pyroptosis in myocardial ischemia-reperfusion injury (MIRI). To this end, the differentially expressed genes were obtained from the GSE4105 dataset using the "GEO2R" online tool. Protein-protein interaction networks were constructed using the Search Tool for the Retrieval of Interacting Genes (STRING) database, and Module and Go analysis were conducted using the Cytoscape 3.6 plugs-in MCODE and BINGO, respectively. The analysis showed that postn was a critical gene in the most significant module. Experimental results, including triphenyltetrazolium chloride staining, pathological analysis, TUNEL staining, western blotting, and RT-qPCR assays, showed that MIRI induced caspase-1-mediated pyroptosis by activating the NLRP3 inflammasome. Postn was significantly upregulated in the heart tissues of MIRI rats and in H9C2 cells following hypoxia/reoxygenation (H/R) treatment. In addition, knockdown of postn suppressed the caspase-1-mediated pyroptosis and H/R-mediated NLRP3 inflammasome activation, as evidenced by flow cytometry, CCK8, RT-qPCR, western blotting, and ELISA assays. In contrast, overexpression of postn promoted NLRP3 inflammasome-mediated pyroptosis of H/R-treated H9C2 cells. According to the results of rescue experiments, a caspase-1 inhibitor reduced the increase in NLRP3 inflammasome-mediated pyroptosis induced by overexpression of postn, and the pyroptosis-promoting function of postn overexpression in H/R treated H9C2 cells was reversed by inhibition of NLRP3. In conclusion, postn overexpression promoted the caspase-1-mediated pyroptosis during MIRI by activating the NLRP3.

Heat Shock Protein 70 Protects the Heart from Ischemia/Reperfusion Injury through Inhibition of p38 MAPK Signaling.

BACKGROUND: Heat shock protein 70 (Hsp70) has been shown to exert cardioprotection. Intracellular calcium ([Ca2+]i) overload induced by p38 mitogen-activated protein kinase (p38 MAPK) activation contributes to cardiac ischemia/reperfusion (I/R) injury. However, whether Hsp70 interacts with p38 MAPK signaling is unclear. Therefore, this study investigated the regulation of p38 MAPK by Hsp70 in I/R-induced cardiac injury. METHODS: Neonatal rat cardiomyocytes were subjected to oxygen-glucose deprivation for 6 h followed by 2 h reoxygenation (OGD/R), and rats underwent left anterior artery ligation for 30 min followed by 30 min of reperfusion. The p38 MAPK inhibitor (SB203580), Hsp70 inhibitor (Quercetin), and Hsp70 short hairpin RNA (shRNA) were used prior to OGD/R or I/R. Cell viability, lactate dehydrogenase (LDH) release, serum cardiac troponin I (cTnI), [Ca2+]i levels, cell apoptosis, myocardial infarct size, mRNA level of IL-1ß and IL-6, and protein expression of Hsp70, phosphorylated p38 MAPK (p-p38 MAPK), sarcoplasmic/endoplasmic reticulum Ca2+-ATPase2 (SERCA2), phosphorylated signal transducer and activator of transcription3 (p-STAT3), and cleaved caspase3 were assessed. RESULTS: Pretreatment with a p38 MAPK inhibitor, SB203580, significantly attenuated OGD/R-induced cell injury or I/R-induced myocardial injury, as evidenced by improved cell viability and lower LDH release, resulted in lower serum cTnI and myocardial infarct size, alleviation of [Ca2+]i overload and cell apoptosis, inhibition of IL-1ß and IL-6, and modulation of protein expressions of p-p38 MAPK, SERCA2, p-STAT3, and cleaved-caspase3. Knockdown of Hsp70 by shRNA exacerbated OGD/R-induced cell injury, which was effectively abolished by SB203580. Moreover, inhibition of Hsp70 by quercetin enhanced I/R-induced myocardial injury, while SB203580 pretreatment reversed the harmful effects caused by quercetin. CONCLUSIONS: Inhibition of Hsp70 aggravates [Ca2+]i overload, inflammation, and apoptosis through regulating p38 MAPK signaling during cardiac I/R injury, which may help provide novel insight into cardioprotective strategies.

Erratum: Low-affinity neurotrophin receptor p75 of brain-derived neurotrophic factor contributes to cancer-induced bone pain by upregulating mTOR signaling.

[This corrects the article DOI: 10.3892/etm.2019.8097.].

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.

Low-affinity neurotrophin receptor p75 of brain-derived neurotrophic factor contributes to cancer-induced bone pain by upregulating mTOR signaling.

Crucial to the development and maintenance of pain sensations is neurotrophin receptor p75 (p75NTR), the low affinity receptor of brain-derived neurotrophic factor (BDNF). This receptor is widespread among dorsal root ganglion (DRG) neurons and the spinal cord. Few reports have demonstrated the specific role of p75NTR in the development of cancer-induced bone pain (CIBP). Therefore the present study examined whether p75NTR contributed to CIBP by upregulating mammalian target of rapamycin (mTOR) signaling. A CIBP rat model was induced and reverse transcription-quantitative polymerase chain reaction was employed to determine p75NTR and mTOR mRNA expression. Immunofluorescence analysis was performed to determine the coexpression of p75NTR and mTOR in DRG neurons, as well as the spinal cord. Von Frey filaments were used to measure the 50% likelihood of paw withdrawal thresholds (PWTs). Spontaneous pain was assessed by ambulatory score. The results demonstrated that compared with the control group, mTOR activation in primary cultured DRG neurons was significantly increased. In addition, mTOR and p75NTR expression was significantly enhanced in the BDNF-treated primary DRG in the BDNF group. In vivo experiments determined that mTOR and p75NTR levels were increased in the CIBP rats compared with the sham group. PWT, in response to mechanical stimulation, was significantly lower compared with that in sham rats and the ambulatory score was significantly higher than that in sham rats. Finally, intrathecal injection of a p75NTR-targeting small interfering RNA significantly decreased mTOR and p75NTR expression levels in DRG neurons and the spinal cord of CIBP rats, as well as partially reversing the decline in PWTs and the increase in ambulatory score. In conclusion, the present study determined that the activation of BDNF/p75NTR/mTOR signaling may participate in nociceptive transmission in CIBP, suggesting a novel mechanism and potential therapeutic target for CIBP treatment and management.

Dexmedetomidine protects H9c2 cardiomyocytes against oxygen-glucose deprivation/reoxygenation-induced intracellular calcium overload and apoptosis through regulating FKBP12.6/RyR2 signaling.

PURPOSE: Intracellular calcium ([Ca2+]i) overload is a major cause of cell injury during myocardial ischemia/reperfusion (I/R). Dexmedetomidine (DEX) has been shown to exert anti-inflammatory and organ protective effects. This study aimed to investigate whether pretreatment with DEX could protect H9c2 cardiomyocytes against oxygen-glucose deprivation/reoxygenation (OGD/R) injury through regulating the Ca2+ signaling. METHODS: H9c2 cardiomyocytes were subjected to OGD for 12 h, followed by 3 h of reoxygenation. DEX was administered 1 h prior to OGD/R. Cell viability, lactate dehydrogenase (LDH) release, level of [Ca2+]i, cell apoptosis, and the expression of 12.6-kd FK506-binding protein/ryanodine receptor 2 (FKBP12.6/RyR2) and caspase-3 were assessed. RESULTS: Cells exposed to OGD/R had decreased cell viability, increased LDH release, elevated [Ca2+]i level and apoptosis rate, down-regulated expression of FKBP12.6, and up-regulated expression of phosphorylated-Ser2814-RyR2 and cleaved caspase-3. Pretreatment with DEX significantly blocked the above-mentioned changes, alleviating the OGD/R-induced injury in H9c2 cells. Moreover, knockdown of FKBP12.6 by small interfering RNA abolished the protective effects of DEX. CONCLUSION: This study indicates that DEX pretreatment protects the cardiomyocytes against OGD/R-induced injury by inhibiting [Ca2+]i overload and cell apoptosis via regulating the FKBP12.6/RyR2 signaling. DEX may be used for preventing cardiac I/R injury in the clinical settings.

Cognitive impairment and transcriptomic profile in hippocampus of young mice after multiple neonatal exposures to sevoflurane.

Children with repeated inhalational anesthesia may develop cognitive disorders. This study aimed to investigate the transcriptome-wide response of hippocampus in young mice that had been exposed to multiple sevoflurane in the neonatal period. Mice received 3% sevoflurane for 2 h on postnatal day (PND) 6, 8, and 10, followed by arterial blood gas test on PND 10, behavioral experiments on PND 31-36, and RNA sequencing (RNA-seq) of hippocampus on PND 37. Functional annotation and protein-protein interaction analyses of differentially expressed genes (DEGs) and quantitative reverse transcription polymerase chain reaction (qPCR) were performed. Neonatal sevoflurane exposures induced cognitive and social behavior disorders in young mice. RNA-seq identified a total of 314 DEGs. Several enriched biological processes (ion channels, brain development, learning, and memory) and signaling pathways (oxytocin signaling pathway and glutamatergic, cholinergic, and GABAergic synapses) were highlighted. As hub-proteins, Pten was involved in nervous system development, synapse assembly, learning, memory, and behaviors, Nos3 and Pik3cd in oxytocin signaling pathway, and Cdk16 in exocytosis and phosphorylation. Some top DEGs were validated by qPCR. This study revealed a transcriptome-wide profile in mice hippocampus after multiple neonatal exposures to sevoflurane, promoting better understanding of underlying mechanisms and investigation of preventive strategies.