DNMT3a-mediated methylation of PPARγ promote intervertebral disc degeneration by regulating the NF-κB pathway.

Intervertebral disc degeneration (IVDD) is a common chronic musculoskeletal disease that causes chronic low back pain and imposes an immense financial strain on patients. The pathological mechanisms underlying IVDD have not been fully elucidated. The development of IVDD is closely associated with abnormal epigenetic changes, suggesting that IVDD progression may be controlled by epigenetic mechanisms. Consequently, this study aimed to investigate the role of epigenetic regulation, including DNA methyltransferase 3a (DNMT3a)-mediated methylation and peroxisome proliferator-activated receptor γ (PPARγ) inhibition, in IVDD development. The expression of DNMT3a and PPARγ in early and late IVDD of nucleus pulposus (NP) tissues was detected using immunohistochemistry and western blotting analyses. Cellularly, DNMT3a inhibition significantly inhibited IL-1ß-induced apoptosis and extracellular matrix (ECM) degradation in rat NP cells. Pretreatment with T0070907, a specific inhibitor of PPARγ, significantly reversed the anti-apoptotic and ECM degradation effects of DNMT3a inhibition. Mechanistically, DNMT3a modified PPARγ promoter hypermethylation to activate the nuclear factor-κB (NF-κB) pathway. DNMT3a inhibition alleviated IVDD progression. Conclusively, the results of this study show that DNMT3a activates the NF-κB pathway by modifying PPARγ promoter hypermethylation to promote apoptosis and ECM degradation. Therefore, we believe that the ability of DNMT3a to mediate the PPARγ/NF-κB axis may provide new ideas for the potential pathogenesis of IVDD and may become an attractive target for the treatment of IVDD.

TGF-ß signaling pathway in spinal cord injury: Mechanisms and therapeutic potential.

Spinal cord injury (SCI) is a highly disabling central nervous system injury with a complex pathological process, resulting in severe sensory and motor dysfunction. The current treatment modalities only alleviate its symptoms and cannot effectively intervene or treat its pathological process. Many studies have reported that the transforming growth factor (TGF)-ß signaling pathway plays an important role in neuronal differentiation, growth, survival, and axonal regeneration after central nervous system injury. Furthermore, the TGF-ß signaling pathway has a vital regulatory role in SCI pathophysiology and neural regeneration. Following SCI, regulation of the TGF-ß signaling pathway can suppress inflammation, reduce apoptosis, prevent glial scar formation, and promote neural regeneration. Due to its role in SCI, the TGF-ß signaling pathway could be a potential therapeutic target. This article reported the pathophysiology of SCI, the characteristics of the TGF-ß signaling pathway, the role of the TGF-ß signaling pathway in SCI, and the latest evidence for targeting the TGF-ß signaling pathway for treating SCI. In addition, the limitations and difficulties in TGF-ß signaling pathway research in SCI are discussed, and solutions are provided to address these potential challenges. We hope this will provide a reference for the TGF-ß signaling pathway and SCI research, offering a theoretical basis for targeted therapy of SCI.

The Protein Acetylation after Traumatic Spinal Cord Injury: Mechanisms and Therapeutic Opportunities.

Spinal cord injury (SCI) leads to deficits of various normal functions and is difficult to return to a normal state. Histone and non-histone protein acetylation after SCI is well documented and regulates spinal cord plasticity, axonal growth, and sensory axon regeneration. However, our understanding of protein acetylation after SCI is still limited. In this review, we summarize current research on the role of acetylation of histone and non-histone proteins in regulating neuron growth and axonal regeneration in SCI. Furthermore, we discuss inhibitors and activators targeting acetylation-related enzymes, such as α-tubulin acetyltransferase 1 (αTAT1), histone deacetylase 6 (HDAC6), and sirtuin 2 (SIRT2), to provide promising opportunities for recovery from SCI. In conclusion, a comprehensive understanding of protein acetylation and deacetylation in SCI may contribute to the development of SCI treatment.

Intrathecal Injection of Botulinum Toxin Type A has an Analgesic Effect in Male Rats CCI Model by Inhibiting the Activation of Spinal P2X4R.

Purinergic receptor P2X4 (P2X4R) plays an essential role in neuropathic pain. However, the specific mechanism needs to be clarified. Botulinum toxin type A is a neurotoxin produced by Clostridium botulinum type A. This study found that intrathecal injection of botulinum toxin type A produced an excellent analgesic effect in a rat model of chronic constriction sciatic nerve injury and inhibited the activation of P2X4R, microglia, and astrocytes. The administration of a P2X4R activator can up-regulate the expression of P2X4R and eliminate the analgesic effect of intrathecal injection of botulinum toxin type A. In addition, we found that microglia and astrocytes in the spinal cord of rats injected with botulinum toxin type A were reactivated after administration of the P2X4R activator. Our results suggest that intrathecal injection of botulinum toxin type A has an analgesic effect in a rat model of chronic constriction sciatic nerve injury by inhibiting the activation of P2X4R in the spinal cord.

[Researchers' Knowledge About the Ethical Norms of National Natural Science Foundation of China Funded Medical Research:Current Status and Suggestions].

Objective To understand the current status of Chinese medical researchers' knowledge regarding the ethical norms of the research involving humans or laboratory animals,and provide reference for further improving the ethics review norms. Methods The questionnaire method was employed to survey the applicants for the 2019 projects supported by the Department of Medical Sciences,National Natural Science Foundation of China (NSFC) about their knowledge of ethical requirements.Furthermore,the ethical supervision of the NSFC and affiliations at the project application and implementation stages was analyzed. Results The survey showed that 29.9% medical researchers were familiar with NSFC's ethical requirements for research involving human or laboratory animals.During the project application stage,59.0% affiliations adopted the simplified review method.Regarding the ethical supervison,95.5% medical researchers believed that the affiliations should fulfill the ethical supervision obligations and take relevant measures during the project implementation period.In addition,55.0% medical researchers fully agreed to discuss with the review experts about the ethical issues involved in the project. Conclusions The NSFC should establish rules and regulations to improve institutional management responsibilities and institutionalize the training about research ethics to comprehensively strengthening the training.Taking the management of research project ethics as a starting point,the NSFC should form a multi-party linkage between project funding and management and establish an accountability mechanism for ethics management.Furthermore,the NSFC should double the endeavors at the review of ethical issues during expert review and process management and attach importance to the research,judgment,and prevention of ethical risks.

SKI knockdown suppresses apoptosis and extracellular matrix degradation of nucleus pulposus cells via inhibition of the Wnt/ß-catenin pathway and ameliorates disc degeneration.

This study aimed to determine the effects of SKI on interleukin (IL)-1ß-induced apoptosis of nucleus pulposus (NP) cells, intervertebral disc degeneration (IDD), and the Wnt signaling pathway. NP tissue specimens of different Pfirrmann grades (II-V) were collected from patients with different grades of IDD. Real-time polymerase chain reaction and western blotting were used to compare SKI mRNA and protein expression in NP tissues from patients. Using the IL-1ß-induced IDD model, NP cells were infected with lentivirus-coated si-SKI to downregulate the expression of SKI and treated with LiCl to evaluate the involvement of the Wnt/ß-catenin signaling pathway. Western blotting, immunofluorescence, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining were used to detect NP cell apoptosis, extracellular matrix (ECM) metabolism, and related protein expression changes in the Wnt/ß-catenin signaling pathway. To investigate the role of SKI in vivo, a rat IDD model was established by needle puncture of the intervertebral disc. Rats were injected with lentivirus-coated si-SKI and evaluated by magnetic resonance imaging (MRI), and hematoxylin and eosin (HE) and safranin O staining. SKI expression positively correlated with the severity of human IDD. In the IL-1ß-induced NP cell degeneration model, SKI expression increased significantly and reached a peak at 24 h. SKI knockdown protected against IL-1ß-induced NP cell apoptosis and ECM degradation. LiCl treatment reversed the protective effects of si-SKI on NP cells. Furthermore, lentivirus-coated si-SKI injection partially reversed the NP tissue damage in the IDD model in vivo. SKI knockdown reduced NP cell apoptosis and ECM degradation by inhibiting the Wnt/ß-catenin signaling pathway, ultimately protecting against IDD. Therefore, SKI may be an effective target for IDD treatment.

Insulin-Induced Gene 2 Expression Is Associated with Breast Cancer Metastasis.

Insulin-induced gene 2 (INSIG2) functions as a blocker of cholesterol biosynthesis and has been shown to be involved in colon and pancreatic cancer pathogenesis. Cholesterol is a risk factor for breast cancer pathophysiology; however, the underlying mechanisms are not well-defined. Hence, our goal was to determine the role of INISG2 in breast cancer. INSIG2 mRNA and protein expression was correlated to metastatic potential of breast cancer cell lines. Knockdown of INSIG2 inhibited epithelial-to-mesenchymal transition. Conversely, overexpression of INSIG2 induced epithelial-to-mesenchymal transition. Knockdown of INSIG2 did not affect cell proliferation but resulted in altered metabolism in vitro and attenuated experimental metastasis in vivo. Analysis of breast cancer tissue microarrays revealed significantly higher INSIG2 protein expression in breast cancer tissues. INSIG2 protein expression was correlated to hormone receptor status, with significantly higher expression in patients with triple-negative and human epidermal growth factor receptor 2 molecular subtypes of invasive breast cancer. Analysis of The Cancer Genome Atlas, however, revealed significantly lower INSIG2 mRNA expression in triple-negative breast cancer patients. Higher INSIG2 mRNA expression was correlated to poor survival probability. Asian patients with high INSIG2 mRNA expression had significantly lower survival probability compared with Asian patients with low/medium INSIG2 mRNA expression. These results reveal a yet undefined role of INSIG2 in breast cancer, potentially more relevant for breast cancer patients in Asia.

The Role of Sphingomyelin Metabolism in the Protection of Rat Brain Microvascular Endothelial Cells by Mild Hypothermia.

BACKGROUND: Sphingomyelin, composed of ceramide (CER), sphingosine (Sph), and sphingosine-1-phosphate (S1P), is an essential structural component of cellular membranes and plays an important role in the signal transduction regulating cell proliferation, differentiation, and apoptosis. CER is mainly metabolized to Sph, and under the action of sphingosine kinases (SphKs), Sph produces S1P, which can be converted back to Sph by S1P phosphatase. It is suggested that the fate of cells is controlled partly by the interconversion of CER and intracellular S1P. SphK2 is considered the main kinase of S1P synthesis in the central nervous system. The objective of this study was to explore the hypothesis that SphK2 and sphingomyelin metabolism participated in the process of cell apoptosis and the protection of mild hypothermia. METHODS: Rat brain microvascular endothelial cells were divided into groups for intervention of SphK2 inhibitor, SphK2 small interfering RNA (SiRNA) transfection, ischemia-reperfusion, and mild hypothermia. After interventions, cell apoptosis was detected by 4,6-diamino-2-phenyl indole (DAPI) and flow cytometry, the expression of apoptosis-related protein was detected by Western Blot, and SphK2 enzyme activity and the content of sphingomyelin were determined. RESULTS: ABC294640 and transfection of SphK2 SiRNA could increase apoptosis, accompanied by the increase of the expression of proapoptotic genes Caspase3 and Bax and the decrease of the expression of BCL-2. This effect could be partially reversed with mild hypothermia. Ischemia-reperfusion injury, transfection of SphK2 SiRNA, and the addition of ABC294640 could significantly inhibit the activity of SphK2, accompanied by the increase of CERs and the decrease of S1P. Mild hypothermia could reverse the changes of sphingolipids but have no significant effect on the activity of sphk2. CONCLUSIONS: Mild hypothermia can inhibit the occurrence of apoptosis and reverse the changes of apoptosis-related genes and sphingomyelin content induced by ischemia-reperfusion injury, but the effect on sphk2 enzyme activity was not significant.

Effects of chrysophanol on hippocampal damage and mitochondrial autophagy in mice with cerebral ischemia reperfusion.

OBJECTIVE: The cerebral ischemia-reperfusion (I/R) model is crucial for the study of cerebral stroke. Chrysophanol (Chry) can protect nerve damage of mice in cerebral ischemia-reperfusion injury. This study aimed at investigating the neuroprotective effects of chrysophanol through mitochondrial autophagy in mice with ischemia-reperfusion injury. MATERIALS AND METHODS: Adult mice were stochastically divided into five groups: sham, I/R (solvent), I/R+Chry (dose, 10.0ml/kg), I/R+Chry (dose, 1.0ml/kg), and I/R+Chry (dose, 0.1ml/kg). The cerebral ischemia-reperfusion model was made in I/R and I/R+Chry groups. The changes in hippocampal formation were observed by hematoxylin and eosin (H&E) staining. The expressions of LC3B-II and LC3B-I protein in hippocampus were demonstrated by western blot (WB). The fluorescence intensities of NIX, LC3B, and mitochondria were detected by immunohistochemistry fluorescent (IF). RESULTS: Comparing with the I/R group, the I/R+Chry groups showed improvements in reducing the damage on the hippocampus, indicated by the reduced ratio of LC3B-II and LC3B-I protein, decreased fluorescence intensity of NIX and LC3B, and increased intensity of mitochondrial fluorescence. CONCLUSION: Our study showed that chrysophanol may regulate mitochondrial autophagy through NIX protein and alleviate the damage of hippocampus through decreasing the level of mitochondrial autophagy.

Simultaneous determination of six components in commercial Roukou Wuwei pills using ultra-high-performance liquid chromatography with diode-array detector.

An efficient ultra-performance liquid chromatography with diode-array detector method was established for simultaneous determination of six active components in Roukou Wuwei pills, namely gallic acid, piperine, costundide, dehydrocostus lactone, isoalantolactone and alantolactone. Chromatographic separation of six components was successfully achieved on an Waters BEH C18 column (50 × 2.1 mm, 1.7 µm) with a mobile phase composed of acetonitrile and water using a gradient elution. Gallic acid and piperine were detected at 270 nm and 343 nm, respectively; while costundide, dehydrocostus lactone, isoalantolactone and alantolactone were simultaneously measured at 225 nm. All six calibration curves showed good linearity (R2 ≥ 0.9994) between the peak area of each component and corresponding concentration. Relative standard deviations for inter- and intra-day precisions were <0.45 and 0.77%, respectively. The mean recovery rates ranged from 96.72 to 102.2% with relative standard deviations <2.07%. The developed method was validated in terms of linearity, precision and accuracy and then successfully applied for the quality control of commercial Roukou Wuwei samples.

Preparation, characterization and antimicrobial activity of inclusion complexes of Myristica fragrans Hott. essential oil in ß-cyclodextrins.

Inclusion complexes of essential oils with cyclodextrins are an effective way to improve stability and solubility, and turn liquid materials into easy to handle powders. In this work, an essential oil of Myristica fragrans Hott. (MFEO), already used in the food and cosmetics industries, was formulated with beta-cyclodextrins (ß-CD) using a co-precipitation method. The orthogonal array scheme was adapted for the optimization of preparation process. DSC and FT-IR spectroscopy analysis indicated the successful formation of MFEO/ß-CD inclusion complexes, which improved the thermal stability of MFEO. Furthermore, comparing the antimicrobial activity of MFEO/ß-CD inclusion complexes and free essential oil against Staphyloccocus aureus, Staphyloccocus epidermidis, Escherichia coli, Klebsiella pneumoniae, yeast Saccharomyces cerevisiae and Bacillus subtilis, it was found that the antimicrobial effect was enhanced after the formation of inclusion complexes. This study demonstrates the potential for the use of MFEO/ß-CD inclusion complexes in the treatment of bacterial infection.

Knockdown of Ski decreased the reactive astrocytes proliferation in vitro induced by oxygen-glucose deprivation/reoxygenation.

Glia scar is a pathological marker in late phase of brain ischemia disease, which constitutes a major physical biochemical barrier to impede axonal regrowth. Astrocytes are known to be critically involved in the formation of glial scar. However, their response to ischemia and their role in neuroprotection after central nervous system (CNS) injury are not completely clear. Recently, we have demonstrated for the first time that Ski was up-regulated in reactive astrocytes after spinal cord injury in vivo and in vitro, which indicates Ski may be a new molecule that control astrocytes biologic properties after CNS injury. However, its role in the process of reactive astrogliosis after cerebral ischemia and its definite mechanism still remains unknown. This study is to elucidate the role of Ski in reactive astrocytes induced by oxygen-glucose deprivation/reoxygenation (OGD/R) model in vitro. The expression of Ski was proved to be up-regulated in OGD/R model. Meanwhile, Up-regulation of Ski was accompanied with high ratio of EdU (+) cells and up-expression of related proteins including GFAP, PCNA, CDK4, and CyclinD1, which demonstrated the distinct activation and proliferation of astrocytes after stimulation by OGD/R. Astrocytes were transfected with Ski-specific siRNA to knockdown Ski expression and subsequently attenuated OGD-induced astrocyte proliferation. Our results also showed that Ski down-regulation could suppress the activity of the Ras-Raf-ERK1/2 signaling pathway. Together, knockdown of Ski can effectively inhibit the proliferation of reactive astrogliosis via suppressing the Ras-Raf-ERK1/2 pathway. These findings indicated that maybe Ski is a promising therapeutic target for cerebral ischemic injury.

Effectiveness of Antibiotic Use Management in Tianjin (2011-2013): A Quasi-Experimental Study.

BACKGROUND In this study we investigated changes in the status of antibiotic use in Tianjin since the implementation of the Antibiotic Stewardship Program (ASP) (2011-2013), as well as existing problems, strategies, and outcomes to promote rational clinical antibiotic use. MATERIAL AND METHODS A quasi-experimental study was performed to investigate situations of antibiotic use in secondary and tertiary general hospitals in Tianjin from April 2011 to 2013. Five major indicators were analyzed: percentage of antibiotic use in inpatient cases (%), antibacterial use density (AUD), proportion of prophylactic antibiotic application for type I surgical incision, compliance rate of medication administration 0.5-2.0 h before such procedures, and antibiotic prophylaxis for ≤24 h in patients receiving these surgeries. RESULTS There was a decrease in the percentage of antibiotic use across general hospitals (60.38% to 46.88%), in AUD (51.60% to 35.37%), and in the proportion of prophylactic antibiotic applications for type I incisions (86.67% to 25.08%). For patients undergoing these procedures, there was an increased compliance rate of medication administration of 0.5-2.0 h prior to surgery (86.38% to 100%), and of antibiotic prophylactic use for ≤24 h (40.30% to 96.37%). CONCLUSIONS Implementation of the ASP campaign has reduced irrational antibiotic use, promoted rational antibiotic use, and delayed antibiotic resistance.

Cyclophosphamide enhances anti-tumor effects of a fibroblast activation protein α-based DNA vaccine in tumor-bearing mice with murine breast carcinoma.

Cyclophosphamide (CY) is a DNA alkylating agent, which is widely used with other chemotherapy drugs in the treatment of various types of cancer. It can be used not only as a chemotherapeutic but also as an immunomodulatory agent to inhibit IL-10 expression and T regulatory cells (Tregs). Fibroblast activation protein α (FAPα) is expressed in cancer-associated fibroblasts in the tumor microenvironment. Immunotherapy based on FAPα, as a tumor stromal antigen, typically induces specific immune response targeting the tumor microenvironment. This study evaluated the efficacy of a previously unreported CY combination strategy to enhance the limited anti-tumor effect of a DNA vaccine targeting FAPα. The results suggested CY administration could promote the percentage of splenic CD8+ T cells and decrease the proportion of CD4 + CD25 + Foxp3+ Tregs in spleen. In tumor tissues, levels of immunosuppressive cytokines including IL-10 and CXCL-12 were also reduced. Meanwhile, the CY combination did not impair the FAPα-specific immunity induced by the DNA vaccine and further reduced tumor stromal factors. Most importantly, FAP-vaccinated mice also treated with CY chemotherapy showed a marked suppression of tumor growth (inhibition ratio =80%) and a prolongation of survival time. Thus, the combination of FAPα immunotherapy and chemotherapy with CY offers new insights into improving cancer therapies.

Anti-tumor effects of DNA vaccine targeting human fibroblast activation protein α by producing specific immune responses and altering tumor microenvironment in the 4T1 murine breast cancer model.

Fibroblast activation protein α (FAPα) is a tumor stromal antigen overexpressed by cancer-associated fibroblasts (CAFs). CAFs are genetically more stable compared with the tumor cells and immunosuppressive components of the tumor microenvironment, rendering them excellent targets for cancer immunotherapy. DNA vaccines are widely applied due to their safety. To specifically destroy CAFs, we constructed and examined the immunogenicity and anti-tumor immune mechanism of a DNA vaccine expressing human FAPα. This vaccine successfully reduced 4T1 tumor growth through producing FAPα-specific cytotoxic T lymphocyte responses which could kill CAFs, and the decrease in FAPα-expressing CAFs resulted in markedly attenuated expression of collagen I and other stromal factors that benefit the tumor progression. Based on these results, a DNA vaccine targeting human FAPα may be an attractive and effective cancer immunotherapy strategy.

Improvement of anti-tumor immunity of fibroblast activation protein α based vaccines by combination with cyclophosphamide in a murine model of breast cancer.

Fibroblast activation protein α (FAPα) is expressed in cancer-associated fibroblasts (CAFs), which are the main type of cells in the tumor microenvironment. CAFs exert immunosuppressive activity, which can weaken the effects of cancer immunotherapy and mainly account for poor outcomes with therapeutic vaccines. To better target and destroy CAFs, a FAPα vaccine using a modified vaccinia ankara (MVA) vector was constructed and used with a DNA vaccine reported in our previous work for heterologous prime-boost immunizations in mice. This strategy to generate anti-tumor immunity partly reduced 4T1 tumor growth through producing FAPα-specific cytotoxic T lymphocyte responses in a preventive model, but the effect required improvement. Combining the FAPα-based cancer vaccines (CpVR-FAP/MVA-FAP) with cyclophosphamide (CY), which can be used not only as a chemotherapeutic but also an immunomodulatory agent to promote a shift from immunosuppression to immunopotentiation, resulted in markedly enhanced tumor growth inhibition compared with the CpVR-FAP/MVA-FAP group. This strategy achieved synergistic effects in a therapeutic model by improving the tumor inhibition rate by 2.5-fold (90.2%), significantly enhancing cellular immunity and prolonging the survival of 4T1 tumor-bearing mice by 35% compared with the PBS group. Furthermore, CAFs, stromal factors and immunosuppressive factors such as IL-10 and Tregs were also markedly decreased by the CY combination. These results indicated that FAPα-targeted MVA boosting in combination with CY is an effective approach to improving specific anti-tumor immune responses through overcoming immunosuppression. This study may offer important advances in research on clinical cancer immunotherapies by modulating immunosuppressive factors.

[Effect of Resveratrol Preconditioning on Myocardial Dysfunction after Cardiac Arrest in Rats].

OBJECTIVE: To investigate the protective effects and its potential mechanism of resveratrol preconditioning on rat cardiac arrest after return of spontaneous circulation (ROSC) with the study of hemodynamic parameters and nitrative stress in myocardium. METHODS: Cardiac arrest SPF SD rat model was established by transoesophageal cardiac alternating current stimulation. Intervention was implemented 15 min before cardiac arrest. Twenty four rats with ROSC after cardiac arrest were randomly assigned into five groups: vehicle, sham, resveratrol 2.3 mg/kg (A group), resveratrol 0.23 mg/kg (B group) and resveratrol 0.023 mg/kg (C group). Heart rate, mean arterial pressure, and left ventricular variables (+ dp/dtmax and - dp/dtmin) were recorded in 0.5 h, 1.0 h, 2.0 h, 3.0 h, and 4.0 h respectively. Rats were sacrificed at 4 h after ROSC, and hearts were removed for determining expression of inducible nitric oxide synthase (iNOS) protein, myocardial peroxynitrite, and nitrotyrosine. RESULTS: Global ROSC rate was 72.7% after the induction of cardiac arrest. Resveratrol preconditioning did not improve ROSC rate significantly. Heart rate and blood pressure declined at early phase of ROSC, then heart rate recovered to the baseline value, but blood pressure still declined progressively. There were no significant differences between resveratrol groups and vehicle group. Myocardial function worsened progressively even after ROSC. Resveratrol improved cardiac function significantly, especially in lower concentration groups. Myocardial iNOS expression, peroxynitrite, and nitrotyrosine content increased significantly after ROSC. Resveratrol decreased these products significantly, and lower concentration groups did better. CONCLUSION: Resveratrol preconditioning could improve cardiac dysfunction after ROSC, which may be associated with its inhibitory effect on nitrative stress.

Protective effect of low dose gadolinium chloride against isoproterenol-induced myocardial injury in rat.

Acute myocardial injury remains a leading cause of morbidity and mortality worldwide, and large amount of released arachidonic acid (AA) is found to be related to cardiomyocyte apoptosis and necrosis. Previous study suggested that GdCl3 completely abolished AA-induced Ca(2+) response. Thus, this study aims to investigate possible cardioprotection effect of GdCl3 on isoproterenol (ISO)-induced myocardial injury and its underlying mechanism(s). Rats that were randomly allocated to five groups: control, GdCl3, ISO, ISO + GdCl3, and ISO + verapamil. Serum levels of AA and cardiac markers, infarct area, and cell apoptosis in heart were measured by ELISA assay, TTC and TUNEL staining, respectively. Chemical interaction between AA and GdCl3 was evaluated by mass and UV spectrometry. The expressions and translocations of death receptor related molecules into lipid rafts were detected in neonatal rat ventricular myocytes by Western blots. Compared with ISO-administered rats, GdCl3 significantly ameliorated the myocardium injury, demonstrated by restoring serum cardiac troponin I, lactate dehydrogenase, creatine kinase MB and AA to near normal levels, and decreasing infarct area and cell apoptosis. In addition, an activation of AA-Fas pathway was found in ISO-induced myocardial injury, which was abrogated by GdCl3. Furthermore, AA induced cell apoptosis through clustering and activating death receptor related molecules TNFR1, Fas and FADD in lipid rafts, a process significantly prevented by the pretreatment with GdCl3. Finally, GdCl3 at the molar ratio of 1/3 (GdCl3/AA) was mostly effective in abolishing AA-induced Ca(2+) response and cell apoptosis, because an obvious change in the chemical identity of AA was obtained by GdCl3 according to this molar ratio. In conclusion, this study demonstrates for the first time that GdCl3 protects myocardium against ISO-induced cell apoptosis through, at least partly, serving as a scavenger of AA, therefore abolishing its downstream activation of the death receptor regulated apoptosis pathway.

Spotlight on necroptosis: Role in pathogenesis and therapeutic potential of intervertebral disc degeneration.

Intervertebral disc degeneration (IDD) is the leading cause of low back pain, which is one of the major factors leading to disability and severe economic burden. Necroptosis is an important form of programmed cell death (PCD), a highly regulated caspase-independent type of cell death that is regulated by receptor-interacting protein kinase 1 (RIPK1), RIPK3 and mixed lineage kinase domain-like protein (MLKL)-mediated, play a key role in the pathophysiology of various inflammatory, infectious and degenerative diseases. Recent studies have shown that necroptosis plays an important role in the occurrence and development of IDD. In this review, we provide an overview of the initiation and execution of necroptosis and explore in depth its potential mechanisms of action in IDD. The analysis focuses on the connection between NP cell necroptosis and mitochondrial dysfunction-oxidative stress pathway, inflammation, endoplasmic reticulum stress, apoptosis, and autophagy. Finally, we evaluated the possibility of treating IDD by inhibiting necroptosis, and believed that targeting necroptosis may be a new strategy to alleviate the symptoms of IDD.

Acid-sensing Ion Channels: Implications for Intervertebral Disc Degeneration.

Intervertebral disc degeneration (IDD) is the leading cause of lower back pain and seriously affects the quality of life of patients. The intervertebral disc (IVD) is an environment of hypoxia, ischemia, acidity, and hypertonicity. Matrix acidity potentially negatively affects gene expression, activity, proliferation, and apoptosis of IVD cells. Acid-sensing ion channels (ASICs) are a group of proton-gated ion channels that play important roles in physiological and pathological conditions. The distribution of ASICs in the nucleus pulposus (NP), annulus fibrosus, cartilage endplate, and nucleus pulposus mesenchymal stem cells (NP-MSCs), as well as the special functions of ASIC1a and ASIC3, show that ASICs play an important role in IDD. In this review, we comprehensively discuss the roles of ASICs in the development and basic pathology of IDD and their potential relevance as therapeutic targets. A deeper understanding of the roles of ASICs in these processes may provide novel therapeutic targets for IDD prevention and treatment.