Blockade of the ADAM8-Fra-1 complex attenuates neuroinflammation by suppressing the Map3k4/MAPKs axis after spinal cord injury.

BACKGROUND: Mechanical spinal cord injury (SCI) is a deteriorative neurological disorder, causing secondary neuroinflammation and neuropathy. ADAM8 is thought to be an extracellular metalloproteinase, which regulates proteolysis and cell adherence, but whether its intracellular region is involved in regulating neuroinflammation in microglia after SCI is unclear. METHODS: Using animal tissue RNA-Seq and clinical blood sample examinations, we found that a specific up-regulation of ADAM8 in microglia was associated with inflammation after SCI. In vitro, microglia stimulated by HMGB1, the tail region of ADAM8, promoted microglial inflammation, migration and proliferation by directly interacting with ERKs and Fra-1 to promote activation, then further activated Map3k4/JNKs/p38. Using SCI mice, we used BK-1361, a specific inhibitor of ADAM8, to treat these mice. RESULTS: The results showed that administration of BK-1361 attenuated the level of neuroinflammation and reduced microglial activation and recruitment by inhibiting the ADAM8/Fra-1 axis. Furthermore, treatment with BK-1361 alleviated glial scar formation, and also preserved myelin and axonal structures. The locomotor recovery of SCI mice treated with BK-1361 was therefore better than those without treatment. CONCLUSIONS: Taken together, the results showed that ADAM8 was a critical molecule, which positively regulated neuroinflammatory development and secondary pathogenesis by promoting microglial activation and migration. Mechanically, ADAM8 formed a complex with ERK and Fra-1 to further activate the Map3k4/JNK/p38 axis in microglia. Inhibition of ADAM8 by treatment with BK-1361 decreased the levels of neuroinflammation, glial formation, and neurohistological loss, leading to favorable improvement in locomotor functional recovery in SCI mice.

Camk2a suppresses denervated muscle atrophy by maintaining the Ca2+ homeostasis in muscle cells.

Denervated muscle atrophy is a severe neurological complication that significantly impacts patients' quality of life. Currently, there is a lack of effective treatment methods. This study aims to investigate the molecular mechanisms associated with denervated muscle atrophy and explore potential therapeutic targets. In this study, we assessed the severity of denervated muscle atrophy by measuring the wet-weight ratio of the calf muscles. We conducted Western blot and immunofluorescence experiments to observe the morphology and cross-sectional area of muscle fibers following sciatic nerve transection. Simultaneously, we evaluated the expression of Camk2a in muscle tissue and measured changes in Ca2+ using the BCA method. Additionally, we performed HE and Sirius Red staining on denervated muscle tissue to observe the cross-sectional area of muscle fibers and collagen deposition in response to Camk2a overexpression. In our study, We observed a significant decrease in the wet weight ratio of the muscles, myosin, and muscle fiber cross-sectional area with the prolonged duration of sciatic nerve transection. Subsequently, we observed varying degrees of elevation in Ca2+ levels in denervated muscle tissue, while Camk2a, which regulates Ca2+ signal transduction, significantly decreased in denervated muscle tissue. Overexpression of Camk2a reduced the accumulation of Ca2+ in muscle tissue, resulting in higher muscle wet weight ratios, larger muscle fiber cross-sectional areas, and a significant reduction in collagen deposition in muscle tissue. In conclusion, our study provides the first evidence that Camk2a can alleviate calcium overload in muscle cells and ameliorate denervated muscle atrophy. Our findings suggest that Camk2a may serve as a crucial regulatory target in denervated muscle atrophy.

A Disintegrin and Metalloproteinase-8 Protects Against Erastin-Induced Neuronal Ferroptosis via Activating Nrf2/HO-1/FTH1 Signaling Pathway.

Ferroptosis is a type of iron-dependent programmed cell death caused by the imbalance between oxidants and antioxidants. A disintegrin and metalloproteinase-8 (ADAM8) is a metalloproteinase that mediates cell adhesion, cell migration, and proteolytic activity. However, the molecular mechanism of ADAM8 regulating ferroptosis after neural disorder is unclear, especially in the neuron. In the present study, we identified the protective role of ADAM8 in Erastin-induced ferroptosis in vitro of the HT22 cells. It was found that overexpression of ADAM8 resulted in upregulated expression of GPX4 and FTH1 along with the decreased reactive oxygen species (ROS) production and reduced neuronal death; however, knockdown of ADAM8 resulted in an opposite. Mechanically, using the Nrf2 activator NK-252 and inhibitor nrf2-IN-1, we dmonstrated that ADAM8 regulates Erastin-mediated neuronal ferroptosis via activating the Nrf2/HO-1/FTH1 signaling pathway. In conclusion, the current study suggested that ADAM8 inhibited Erastin-induced neuronal ferroptosis through activating the Nrf2/HO-1/FTH1 signaling pathway, playing a protective role in vitro of the HT22 cell line. ADAM8 may be a promising and feasible target for neuronal survival in diseases of neural disorder.

Controllable release of nitric oxide from an injectable alginate hydrogel.

Currently, the controlled release of nitric oxide (NO) plays a crucial role in various biomedical applications. However, injectable NO-releasing materials remain an underexplored research field to date. In this study, via the incorporation of S-nitroso-N-acetyl-penicillamine (SNAP) as an NO donor, a family of NO-releasing injectable hydrogels was synthesized through the in situ cross-linking between sodium alginate and calcium ion induced by D-(+)-gluconate δ-lactone as an initiator. Initially, the organic functional groups and the corresponding morphologies of the resulting injectable hydrogels were characterized by IR and SEM spectroscopies, respectively. The NO release times of hydrogels with different SNAP loading amounts could reach up to 36-47 h. Due to the release of NO, the highest antibacterial rates of these injectable hydrogels against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were up to 95 %, respectively. Furthermore, the matrix of these hydrogels demonstrated great water absorption ability, swelling behavior, and degradation performance. Finally, we expect that these NO-releasing injectable hydrogels could have great potential applications various biomedical material fields.

Growth Differentiation Factor 15 Regulates Oxidative Stress-Dependent Ferroptosis Post Spinal Cord Injury by Stabilizing the p62-Keap1-Nrf2 Signaling Pathway.

Background: Spinal cord injury (SCI) is a severe traumatic disorder of the central nervous system (CNS) that causes irreversible damage to the nervous tissue. The consequent hemorrhage contributed by trauma induces neuronal ferroptosis post SCI, which is an important death mode to mediate neuronal loss. Growth differentiation factor 15 (GDF15) is a cytokine that regulates cell proliferation, differentiation, and death. However, the specific role of GDF15 in neuronal ferroptosis post SCI remains unknown. Materials and Methods: Neuronal ferroptosis in vitro was measured by detection of lipid peroxidation, glutathione, iron content, and reactive oxidative stress. In vivo, western blotting and immunofluorescence (IF) staining was utilized to measure ferroptosis post SCI. IF staining, TUNEL staining, hematoxylin-eosin staining, and Nissl staining were used to measure neurological damage. Finally, locomotor function recovery was analyzed using the Basso Mouse Scale and Louisville Swim Scale. Results: GDF15 was significantly increased in neuronal ferroptosis and silencing GDF15 aggravated ferroptosis both in vitro and in vivo. Besides, GDF15-mediated inhibition of neuronal ferroptosis is through p62-dependent Keap1-Nrf2 pathway. In SCI mice, knockdown of GDF15 significantly exacerbated neuronal death, interfered with axon regeneration and remyelination, aggravated ferroptosis-mediated neuroinflammation, and restrained locomotor recovery. Conclusion: GDF15 effectively alleviated neuronal ferroptosis post SCI via the p62-Keap1-Nrf2 signaling pathway and promoted locomotor recovery of SCI mice, which is suggested as a potential target on SCI pathogenesis and treatment.

FANCC deficiency mediates microglial pyroptosis and secondary neuronal apoptosis in spinal cord contusion.

BACKGROUND: Traumatic spinal cord injury (SCI)-induced neuroinflammation results in secondary neurological destruction and functional disorder. Previous findings showed that microglial pyroptosis plays a crucial role in neuroinflammation. Thus, it is necessary to conduct a comprehensive investigation of the mechanisms associated with post-SCI microglial pyroptosis. The Fanconi Anemia Group C complementation group gene (FANCC) has been previously reported to have an anti-inflammation effect; however, whether it can regulate microglial pyroptosis remains unknown. Therefore, we probed the mechanism associated with FANCC-mediated microglial pyroptosis and neuroinflammation in vitro and in vivo in SCI mice. METHODS: Microglial pyroptosis was assessed by western blotting (WB) and immunofluorescence (IF), whereas microglial-induced neuroinflammation was evaluated by WB, Enzyme-linked immunosorbent assays and IF. Besides, flow cytometry, TdT-mediated dUTP Nick-End Labeling staining and WB were employed to examine the level of neuronal apoptosis. Morphological changes in neurons were assessed by hematoxylin-eosin and Luxol Fast Blue staining. Finally, locomotor function rehabilitation was analyzed using the Basso Mouse Scale and Louisville Swim Scale. RESULTS: Overexpression of FANCC suppressed microglial pyroptosis via inhibiting p38/NLRP3 expression, which in turn reduced neuronal apoptosis. By contrast, knockdown of FANCC increased the degree of neuronal apoptosis by aggravating microglial pyroptosis. Besides, increased glial scar formation, severe myelin sheath destruction and poor axon outgrowth were observed in the mice transfected with short hairpin RNA of FANCC post SCI, which caused reduced locomotor function recovery. CONCLUSIONS: Taken together, a previously unknown role of FANCC was identified in SCI, where its deficiency led to microglia pyroptosis, neuronal apoptosis and neurological damage. Mechanistically, FANCC mediated microglia pyroptosis and the inflammatory response via regulating the p38/NLRP3 pathway.

Effect of Carbon Dioxide on Bispectral Index of EEG under Intravenous Target-Controlled Anesthesia Based on Intelligent Medical Treatment.

Laparoscopic surgery has the advantages of less trauma and quick recovery, and it is more and more favored by surgeons and patients in clinical practice. However, the impact of carbon dioxide pneumoperitoneum on the body during laparoscopic surgery has attracted the attention of many scholars. Pneumoperitoneum can cause increased cerebral blood flow and increased intracranial pressure, cerebral metabolic rate is highly correlated with blood carbon dioxide partial pressure, and cerebral metabolism without cardiopulmonary bypass is linearly correlated with the depth of anesthesia. Electroencephalographic (EEG) bispectral index (BIS) is a signal analysis method, which can directly measure the effect of drugs on the cerebral cortex and reflect the depth of anesthesia. Based on this, this study takes smart medical treatment as the background and uses the improved BP neural network as a tool to explore the effect of carbon dioxide on EEG bispectral index under intravenous target-controlled anesthesia. The main purpose is to observe the correlation between arterial blood carbon dioxide partial pressure and EEG bispectral index under propofol target-controlled anesthesia during retroperitoneal laparoscopic surgery. The experimental results show that the model proposed in this study can efficiently and accurately obtain the size of the influencing factors, which provides a clinical basis for the anesthesia management and anesthesia depth regulation of carbon dioxide pneumoperitoneum laparoscopic surgery.

Rationally designed NiMn LDH@NiCo2O4core-shell structures for high energy density supercapacitor and enzyme-free glucose sensor.

Exploring high-efficiency and low-cost bifunctional electrodes for supercapacitors and sensors is significant but challenging. Most of the existing electrodes are mostly single-functional materials with simple structure. Herein, NiCo2O4nanowires as the core and NiMn layered double hydroxide (LDH) as the shell is directly grownin situon carbon cloth (CC) to form a heterostructure (NiMn LDH@NiCo2O4/CC). The performance in supercapacitors and enzyme-free glucose sensing has been systematically studied. Compared with a single NiCo2O4nanowire or NiMn LDH nanosheet, the heterogeneous interface produced by the unique core-shell structure has stronger electronic interaction and abundant active surface area, which shows excellent electrochemical performance. Electrochemical tests demonstrate that the NiMn LDH@NiCo2O4/CC core-shell electrode possesses an area specific capacitance of 2.40 F cm-2and a rate capability of 76.22% at 20 mA cm-2. Simultaneously, asymmetric supercapacitor is assembled with it as the positive electrode and NiFe LDH@NiCo2O4/CC as the negative electrode. The supercapacitor possesses an energy density of 47.74 Wh kg-1when the power density is 175 W kg-1, revealing excellent performance and maintains cycle stability of 93.48% after 6000 cycles at 10 mA cm-2. Additionally, the electrode applied as enzyme-free glucose sensor electrode also displays outstanding sensitivity of 2139µA mM-1cm-2, wide detection range (2µM-3mM and 4-8 mM) and low detection limit of 210 nM, representing good anti-interference performance. This work reveals the multi-metal synergy and rationally designed core-shell structure is critical to the electrochemical performance of bifunctional electrodes.

Advanced glycation end products induce neural tube defects through elevating oxidative stress in mice.

Our previous study showed an association between advanced glycation end products (AGEs) and neural tube defects (NTDs). To understand the molecular mechanisms underlying the effect of AGEs on neural tube development, C57BL/6 female mice were fed for 4 weeks with commercial food containing 3% advanced glycation end product bovine serum albumin (AGE-BSA) or 3% bovine serum albumin (BSA) as a control. After mating mice, oxidative stress markers including malondialdehyde and H2O2 were measured at embryonic day 7.5 (E7.5) of gestation, and the level of intracellular reactive oxygen species (ROS) in embryonic cells was determined at E8.5. In addition to evaluating NTDs, an enzyme-linked immunosorbent assay was used to determine the effect of embryonic protein administration on the N-(carboxymethyl) lysine reactivity of acid and carboxyethyl lysine antibodies at E10.5. The results showed a remarkable increase in the incidence of NTDs at E10.5 in embryos of mice fed with AGE-BSA (no hyperglycemia) compared with control mice. Moreover, embryonic protein administration resulted in a noticeable increase in the reactivity of N-(carboxymethyl) lysine and N(ε)-(carboxyethyl) lysine antibodies. Malondialdehyde and H2O2 levels in embryonic cells were increased at E7.5, followed by increased intracellular ROS levels at E8.5. Vitamin E supplementation could partially recover these phenomena. Collectively, these results suggest that AGE-BSA could induce NTDs in the absence of hyperglycemia by an underlying mechanism that is at least partially associated with its capacity to increase embryonic oxidative stress levels.

Erythrocyte osmotic fragility increases with serum advanced glycated end products in cigarette smokers.

BACKGROUND: This study examines the relationship between circulating advanced glycated end products (AGEs) level and erythrocyte osmotic fragility in smokers. METHODS: Forty-eight smokers (aged 45 ± 5 years) and fifty healthy nonsmokers (aged 42 ± 6 years) were selected in this study. All subjects were analysed according to serum AGEs, osmotic fragility (H50, the NaCL concentration producing 50% hemolysis), malondialdehyde (MDA) and advanced oxidation protein products (AOPP). RESULTS: The data show that the serum AGEs, H50, MDA and AOPP levels were significantly higher for smokers than that of nonsmokers (p < 0.01). The serum AGEs correlated with H50 in smokers (r = 0.7703, p < 0.01). MDA levels correlated with H50 in smokers (r = 0.7584, p < 0.01). CONCLUSIONS: This study demonstrated that serum AGEs and MDA levels positively correlated with osmotic fragility in smokers.

Maternal serum AGEs levels in pregnancies associated with neural tube defects.

Advanced glycation end products (AGEs) plays an important role in diabetic embryopathy. AGE-mediated DNA damage could be a significant factor in the teratogenicity. The aim of the present study was to evaluate the association between the AGEs level and neural tube defects (NTDs) occurrence risk. Forty-eight mothers with NTD-affected pregnancies and 50 normal mothers were selected in this study. Blood were collected from the mothers and were assayed for serum AGEs, malondiadehyde (MDA) and hemoglobin A1c (HbA1c). Data were analyzed by logistic regression method. The study indicated that there were significant but modest lower prevalence for cases mothers on age, BMI and glucose levels compared with controls. NTD-affected mothers were significantly more likely to have higher AGEs levels (5.6±0.48 AU vs. 4.6±0.68 AU ρ<0.01) than controls. The AGEs levels were not correlated with MDA and HbA1c in NTDs mothers (r(2)=0.0006 p=0.8691 and r(2)=0.001 p=0.8172, respectively). The conclusion is that AGEs might be associated with NTDs occurrence.

Hypoxic stress in diabetic pregnancy contributes to impaired embryo gene expression and defective development by inducing oxidative stress.

We have shown that neural tube defects (NTD) in a mouse model of diabetic embryopathy are associated with deficient expression of Pax3, a gene required for neural tube closure. Hyperglycemia-induced oxidative stress is responsible. Before organogenesis, the avascular embryo is physiologically hypoxic (2-5% O(2)). Here we hypothesized that, because O(2) delivery is limited at this stage of development, excess glucose metabolism could accelerate the rate of O(2) consumption, thereby exacerbating the hypoxic state. Because hypoxia can increase mitochondrial superoxide production, excessive hypoxia may contribute to oxidative stress. To test this, we assayed O(2) flux, an indicator of O(2) availability, in embryos of glucose-injected hyperglycemic or saline-injected mice. O(2) flux was reduced by 30% in embryos of hyperglycemic mice. To test whether hypoxia replicates, and hyperoxia suppresses, the effects of maternal hyperglycemia, pregnant mice were housed in controlled O(2) chambers on embryonic day 7.5. Housing pregnant mice in 12% O(2), or induction of maternal hyperglycemia (>250 mg/dl), decreased Pax3 expression fivefold, and increased NTD eightfold. Conversely, housing pregnant diabetic mice in 30% O(2) significantly suppressed the effect of maternal diabetes to increase NTD. These effects of hypoxia appear to be the result of increased production of mitochondrial superoxide, as indicated by assay of lipid peroxidation, reduced glutathione, and H(2)O(2). Further support of this interpretation was the effect of antioxidants, which blocked the effects of maternal hypoxia, as well as hyperglycemia, on Pax3 expression and NTD. These observations suggest that maternal hyperglycemia depletes O(2) in the embryo and that this contributes to oxidative stress and the adverse effects of maternal hyperglycemia on embryo development.

Evaluation of dot immunogold filtration assay for anti-HAV IgM antibody.

AIM:To detect hepatitis A virus-specific immunoglobulin M (IgM) antibody rapidly.METHODS:Colloidal gold with an average diameter of 15nm was prepared by controlled reduction of a boiling solution of 0.2g/L chloroauric acid with 10g/L sodium citrate and labeled with anti-HAVIgG as gold probe. Dot immunogold filtration assay (DIGFA) has been developed by coating anti-human &mgr; chain on nitrocellulose membrane (NCM) for capturing the anti-HAV IgM in serum, then using cultured hepatitis A antigen as a bridge , connecting anti-HAV IgM in sample and anti-HAV IgG labeled colloidal gold. If there was anti-HAV IgM in sample, gold probes would concentrate on NCM, which will appear a pink dot.RESULTS:A total of 264 serum samples were comparatively detected with both DIGFA and ELISA by blind method. Among them, 88 were positive and 146 were negative with the two methods. The sensitivity and the specificity of DIGFA were 86.27% and 90.12%, respectively. Fifteen negative serum samples and 15 positive serum samples were detected 3 times repeatedly, the results were the same.CONCLUSION:DIGFA is a simple, rapid, sensitive, specific and reliable method without expensive equipment and is not interfered with rheumatoid factor (RF) in serum. It is suitable for basic medical laboratories. The test could be applied for diagnosis and epidemiological survey of hepatitis A. It has a broad prospect in application.