Apoptosis Of Hippocampal Neurons Research Articles

Nuclear translocation of GluA2/ GAPDH promotes neurotoxicity after pilocarpine-induced epilepsy

Recent studies have identified that glyceraldehyde-3-phosphate dehydrogenase (GAPDH) exerts multiple functions besides its role in energy metabolism. It can form a protein complex with GluA2 subunit of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs), translocate into nucleus and confer neurotoxicity in a cerebral ischemia model. We postulate that GAPDH may also induce neurotoxicity by forming a coupling with GluA2 in pilocarpine-induced epileptic model, and disruption of the GluA2/GAPDH coupling can protect against neuronal injury. In this study, induced status epilepticus (SE) in rats by the systemic administration of pilocarpine, collected hippocampal tissues at different time points after SE, and assessed the relationship between GluA2/GAPDH coupling and neuronal apoptosis in SE rats. Then, we interrupted the GluA2/GAPDH coupling by a special interfering peptide and determined whether neuronal injury can be rescued and hippocampus-depended memory function can be improved. We also evaluated the concentrations of GAPDH in nuclear and cytoplasmatic proteins in SE group, non-SE group and after interruption of GluA2/GAPDH coupling, to verify the nuclear translocation of GAPDH in SE model. We found that the apoptosis of hippocampal neurons was most significant at 72 h after SE, which was also the peak time of GluA2/GAPDH coupling expression and GluA2 consumption. After interruption of GluA2/GAPDH coupling, the apoptosis and memorial function of hippocampal neurons were improved and nuclear translocation of GluA2/GAPDH coupling was reduced. In conclusion, GAPDH can be translocated into nucleus in the form of GluA2/GAPDH, which plays an important role in regulating pilocarpine-induced epilepsy via neurotoxicity pathway.

Amyloid Beta Oligomers-Induced Ca2+ Entry Pathways: Role of Neuronal Networks, NMDA Receptors and Amyloid Channel Formation.

The molecular basis of amyloid toxicity in Alzheimer’s disease (AD) remains controversial. Amyloid β (Aβ) oligomers promote Ca2+ influx, mitochondrial Ca2+ overload and apoptosis in hippocampal neurons in vivo and in vitro, but the primary Ca2+ entry pathways are unclear. We studied Ca2+ entry pathways induced by Aβ oligomers in rat hippocampal and cerebellar neurons. Aβ oligomers induce Ca2+ entry in neurons. Ca2+ responses to Aβ oligomers are large after synaptic networking and prevented by blockers of synaptic transmission. In contrast, in neurons devoid of synaptic connections, Ca2+ responses to Aβ oligomers are small and prevented only by blockers of amyloid channels (NA7) and NMDA receptors (MK801). A combination of NA7 and MK801 nearly abolished Ca2+ responses. Non-neuronal cells bearing NMDA receptors showed Ca2+ responses to oligomers, whereas cells without NMDA receptors did not exhibit Ca2+ responses. The expression of subunits of the NMDA receptor NR1/ NR2A and NR1/NR2B in HEK293 cells lacking endogenous NMDA receptors restored Ca2+ responses to NMDA but not to Aβ oligomers. We conclude that Aβ oligomers promote Ca2+ entry via amyloid channels and NMDA receptors. This may recruit distant neurons intertwisted by synaptic connections, spreading excitation and recruiting further NMDA receptors and voltage-gated Ca2+ channels, leading to excitotoxicity and neuron degeneration in AD.

MicroRNA 322-5p reduced neuronal inflammation via the TLR4/TRAF6/NF-κB axis in a rat epilepsy model.

This study aimed to determine whether microRNA-322-5p regulates seizure and seizure damage by targeting the TLR4/TRAF6/NF-κB-associated inflammatory signaling pathway. In a pilocarpine-induced epileptic rat model, the expressions of miR-322-5p, TLR4, NF-κB, TRAF6, IRF5, IL-1β, and GABA were assessed by a quantitative polymerase chain reaction and western blotting. Tunel detects hippocampal neuron apoptosis. The results showed that the expression of miR-322-5p significantly decreased in status epilepticus (SE) rats. The reduction of miR-322-5p was accompanied by increased levels of pro-inflammatory cytokines, an increased NF-κB expression, and reduced γ-aminobutyric acid (GABA) levels. Exogenous miR-322-5p reduced the expression of inflammatory molecules and increased the GABA levels in SE rats, and also reduced hippocampal neuronal cell apoptosis caused by epilepsy. In conclusion, the miR-322-5p significantly inhibited the TLR4/TRAF6/NF-κB-associated inflammation and reduced neuronal apoptosis, suggesting that its induction may be of potential interest for novel antiseizure medications.

Aerobic Physical Exercise as a Non-medical Intervention for Brain Dysfunction: State of the Art and Beyond.

Brain disorders, including stroke, Alzheimer's disease, depression, and chronic pain, are difficult to effectively treat. These major brain disorders have high incidence and mortality rates in the general population, and seriously affect not only the patient's quality of life, but also increases the burden of social medical care. Aerobic physical exercise is considered an effective adjuvant therapy for preventing and treating major brain disorders. Although the underlying regulatory mechanisms are still unknown, systemic processes may be involved. Here, this review aimed to reveal that aerobic physical exercise improved depression and several brain functions, including cognitive functions, and provided chronic pain relief. We concluded that aerobic physical exercise helps to maintain the regulatory mechanisms of brain homeostasis through anti-inflammatory mechanisms and enhanced synaptic plasticity and inhibition of hippocampal atrophy and neuronal apoptosis. In addition, we also discussed the cross-system mechanisms of aerobic exercise in regulating imbalances in brain function, such as the “bone-brain axis.” Furthermore, our findings provide a scientific basis for the clinical application of aerobic physical exercise in the fight against brain disorders.

Luteolin Induced Hippocampal Neuronal Pyroptosis Inhibition by Regulation of miR-124-3p/TNF-α/TRAF6 Axis in Mice Affected by Breast-Cancer-Related Depression.

Background Breast-cancer-related depression (BCRD) is associated with an increased mortality rate among breast cancer (BC) survivors. Luteolin has many pharmacological effects, particularly in the treatment of BC. In this study, we aimed to explore the anti-BCRD activity of luteolin and its underlying functional mechanism. Methods A BCRD mouse model was induced by injecting 4T1 cells and corticosterone (COR). Behavioral test, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining, Nissl staining, immunofluorescence, reverse-transcription quantitative PCR (RT-qPCR), and western blotting were used to study the effect of luteolin in mice with BCRD in vivo. A COR-induced neuron injury model was established in HT-22 cells in vitro. The role of miR-124-3p in the anti-BCRD effects of luteolin was studied using a miR-124-3p inhibitor. Results Luteolin significantly reduced the size and weight of the tumor, increased the mice entry frequency in the symmetrical sector, and reduced the duration of immobility in the tail suspension and forced swimming tests of mice affected by BCRD. Simultaneously, apoptosis of hippocampal neurons was inhibited, and the number of Nissl bodies increased with luteolin treatment. In addition, luteolin resulted in the upregulation of miR-124-3p expression in the hippocampus and downregulated the expression of tumor necrosis factor-α (TNF-α) and TNF receptor-associated factor 6 (TRAF6), as well as lowered the phosphorylation levels of nuclear factor-kappa B (NF-κB) and IkappaB (IκB). Luteolin also inhibited pyroptosis of hippocampal neurons in mice affected by BCRD, as revealed by the low protein levels of NOD-like receptor protein 3 (NLRP3), caspase-1, gasdermin D-N (GSDMD-N), interleukin (IL)-1β, and IL-18. However, the miR-124-3p inhibitor significantly reversed the therapeutic effect of luteolin on COR-induced HT-22 cells. Conclusion Our study demonstrated that the anti-BCRD function of luteolin was mediated by regulating the miR-124-3p/TNF-α/TRAF6-related pathway and inhibiting neuronal cell pyroptosis and subsequent inflammation. Therefore, luteolin may be a potential drug candidate in the treatments of BCRD.

Eleutheroside E alleviates cerebral ischemia-reperfusion injury in a 5-hydroxytryptamine receptor 2C (Htr2c)-dependent manner in rats

ABSTRACT Stroke is the central disorder underlined by ischemia-reperfusion (I/R) injury. Eleutheroside E (EE) is administered as the shield in some ischemia tissues with anti-inflammatory action. However, whether EE defends I/R-induced damage in the brain remains unknown. Here, we demonstrated that EE significantly alleviated the cerebral I/R injury and reduced the apoptosis of hippocampal neuron cells in rats. During the anti-apoptosis process, EE significantly upregulated the expression of 5-hydroxytryptamine receptor 2C (Htr2c) gene. Silencing Htr2c expression dramatically weakened the protective effect of EE on I/R-induced apoptosis of rat hippocampal neuron. EE-regulated Htr2c also remarkably inhibited the expression of caspase-3, −6 and −7, thereby suggesting a plausible anti-apoptosis mechanism associated with Htr2c/caspase axis. These findings elicit the potentially clinical strategy that targets Htr2c to improve outcome of ischemia brain.

Mongolian Medicine Areca Thirteen Pill (GY-13) Improved Depressive Syndrome via upregulating cAMP/PKA/CREB/BDNF signaling pathway

Ethnopharmacological relevanceAreca Thirteen Pill, also called Gao You-13 (GY-13), is a traditional Mongolian herbal formula and has been extensively used to treat depression in Mongolian areas, which belongs to Heyi disease in Mongolian medicine. Major depressive disorder is a serious psychiatric disease, only one-third of individuals with depression are responsive to current antidepressants in clinic. Growing attention has been attracted by traditional herbal medicines in fighting depression because they are considered safer alternatives to pharmacotherapy. Aim of the studyTo reveal the mechanism of GY-13 in the treatment of depression. Materials and methodsThe rat depression model was established by chronic unpredictable mild stress (CUMS), and primary hippocampal neurons were used to construct a glutamate-induced excitotoxicity model. The antidepressant effect of GY-13 was then assessed by performing sucrose preference tests, open field tests, and body weight measurements on rats. The expression of cAMP and PKA, mRNA levels of brain-derived neurotrophic factor (BDNF) and cAMP response element binding protein (CREB), and hippocampal neuronal apoptosis were measured. ResultsThe results indicate that GY-13 significantly improves depression-like behavior, rescues decreased cAMP， PKA, recovers the mRNA levels of CREB and BDNF, and increases the proliferative activity of hippocampus. In addition, blockade of PKA reverses the effects of GY-13 treatment on CREB mRNA, BDNF mRNA levels. In vitro, GY-13 treatment increased hippocampal proliferative activity and attenuated Glu-induced apoptosis of hippocampal neurons as well as reduced CREB mRNA and BDNF mRNA expression levels. ConclusionsOur research demonstrated that GY-13 treatment exerted a potent antidepressant action via activation of cAMP/CREB/BDNF signaling pathway, promoting proliferation, and suppressing apoptosis. This research provides molecular biological ground for developing GY-13 into a potent alternative for the intervention of depression.

The microbiota-gut-brain axis participates in chronic cerebral hypoperfusion by disrupting the metabolism of short-chain fatty acids

BackgroundChronic cerebral hypoperfusion (CCH) underlies secondary brain injury following certain metabolic disorders and central nervous system (CNS) diseases. Dysregulation of the microbiota-gut-brain axis can exacerbate various CNS disorders through aberrantly expressed metabolites such as short-chain fatty acids (SCFAs). Yet, its relationship with CCH remains to be demonstrated. And if so, it is of interest to explore whether restoring gut microbiota to maintain SCFA metabolism could protect against CCH.ResultsRats subjected to bilateral common carotid artery occlusion (BCCAO) as a model of CCH exhibited cognitive impairment, depressive-like behaviors, decreased gut motility, and compromised gut barrier functions. The 16S ribosomal RNA gene sequencing revealed an abnormal gut microbiota profile and decreased relative abundance of some representative SCFA producers, with the decreased hippocampal SCFAs as the further evidence. Using fecal microbiota transplantation (FMT), rats recolonized with a balanced gut microbiome acquired a higher level of hippocampal SCFAs, as well as decreased neuroinflammation when exposed to lipopolysaccharide. Healthy FMT promoted gut motility and gut barrier functions, and improved cognitive decline and depressive-like behaviors by inhibiting hippocampal neuronal apoptosis in BCCAO rats. Long-term SCFA supplementation further confirmed its neuroprotective effect in terms of relieving inflammatory response and hippocampal neuronal apoptosis following BCCAO.ConclusionOur results demonstrate that modulating the gut microbiome via FMT can ameliorate BCCAO-induced gut dysbiosis, cognitive decline, and depressive-like behaviors, possibly by enhancing the relative abundance of SCFA-producing floras and subsequently increasing SCFA levels.9q_eednNVPt41Vawjie4QyVideo abstract

CircDYM ameliorates CUMS mice depressive-like behavior and inhibits hippocampal neurons injury via miR-497a-5p/NR3C1 axis

BackgroundDepression is an important mental disease that threatens human physical and mental health. Circular RNA (circRNA) has been confirmed to be involved in the regulation of depression progression, but the role and mechanism of circDYM in depression progression need to be further explored. MethodsChronic unpredictable mild stress (CUMS) mice model was constructed to assess mice depressive-like behavior using novelty-suppressed feeding test, sucrose preference test, social interaction test, and forced swimming test. The expression of circDYM, microRNA (miR)-497a-5p and glucocorticoid receptor (NR3C1) was measured by quantitative real-time PCR. The protein levels of NR3C1 and apoptosis markers were analyzed by western blot analysis. Hippocampal neurons viability, apoptosis and inflammation were detected by cell counting kit 8 assay, flow cytometry and ELISA assay. Furthermore, RNA interaction was confirmed by dual-luciferase reporter assay, RIP assay and RNA pull-down assay. ResultsOur study showed that circDYM and NR3C1 were downregulated and miR-497a-5p was upregulated in the hippocampus tissues of CUMS mice. Overexpressed circDYM alleviated CUMS mice depressive-like behavior and repressed hippocampal neurons injury. In terms of mechanism, circDYM could upregulate NR3C1 by sponging miR-497a-5p. MiR-497a-5p overexpression reversed the regulation of circDYM on CUMS mice depressive-like behavior and hippocampal neurons injury. In addition, the function of miR-497a-5p overexpression on CUMS mice depressive-like behavior and hippocampal neurons injury also could be reversed by overexpressing NR3C1. ConclusionIn summary, our study confirmed that circDYM could relieve the depressive-like behavior in CUMS mice and hippocampal neurons injury through miR-497a-5p/NR3C1 pathway. These data confirmed that circDYM had an anti-depressive function, which might be a potential target for depression treatment.

IDF21-0041 Hyperglycemia aggravates apoptosis and neuroinflammation at the intermediate stage after post-traumatic brain injury

Background: Traumatic brain injury (TBI) is a highly lethal event with a poor prognosis. Recovering residual neuronal function in the intermediate stage of TBI is important for treatment; however, neuroinflammation and neuronal apoptosis impede residual neuronal repair processes. Hyperglycemia influences inflammatory processes and neuronal survival. Aim: We explored the effects of high glucose on neuroinflammation and neuronal death during the intermediate phase of TBI. Method: Rat models of type 2 diabetes mellitus and/or TBI were developed and behaviorally assessed. The histopathological changes were detected by Hematoxylin and eosin staining. Proinflammatory and anti-inflammatory in serum and hippocampal tissue were tested. And neural apoptosis was observed by Tunel staining and the expression of cleaved caspase-3 (CC-3) protein and Bax/Bcl-2 ratio were recorded. In in vitro assays, levels of inflammatory factors and apoptosis associated proteins were measured after MEK5 activation. Immunofluorescence colocalization of neuron-specific nuclear protein and p-MEK5 was analyzed by immunofluorescence cytochemistry. Results: Neurological function and cognitive abilities were impaired in TBI rats and worsened by type 2 diabetes mellitus. Histopathological staining and analyses of serum and hippocampal mRNA and protein levels indicated that neuroinflammation and apoptosis were induced in TBI rats and exacerbated by hyperglycemia. Hyperglycemia inhibited hippocampal MEK5 phosphorylation in TBI rats. In vitro assays were used to assess inflammatory factor expression, apoptotic protein levels and neuronal survival after MEK5 activation in TBI- and/or high-glucose-treated neurons. MEK5/extracellular signal-regulated kinase 5 (ERK5) pathway activation reduced the inflammation, cleaved caspase-3 expression, Bax/Bcl-2 ratio and apoptosis of TBI neurons, even under high-glucose conditions. Discussion: Our results indicated that HG exacerbated hippocampal injury and exaggerated the neurological deficits and learning/memory problems after TBI. We observed that HG aggravated neuroinflammation partly by inhibiting the MEK5/ERK5 signaling pathway. In addition to activating inflammation, HG has been reported to reduce neuronal survival by upregulating CC-3 and disrupting the balance between Bax and Bcl-2. The pro-apoptotic effects of HG have frequently been observed in individuals exposed to prolonged hyperglycemia. ERK5 was found to inhibit endoplasmic reticulum stress and apoptosis in pancreatic β-cells, thereby ameliorating the tissue damage caused by hyperglycemia. In the present study, activation of MEK5/ERK5 may reduced TBI cauded neuronal apoptosis. In conclusion, HG exacerbated hippocampal injury after TBI, largely by disrupting the homeostasis of pro- and anti-inflammatory cytokines and inducing hippocampal neuronal apoptosis. The MEK5/ERK5 pathway participated in both of these processes. These experimental findings emphasize the importance of good glycemic control for the functional recovery of residual neurons in TBI patients.

MiR-129 Regulates Cell Viability in Alzheimer’s Disease Through Targeting Amyloid Precursor Protein (APP)

This study intends to explore miR-129’s effect on cell viability of Alzheimer’s disease by regulating the target gene APP. The hippocampal neurons were assigned into model group (MO group); mimetic group (SI group); inhibitor group (IN group) followed by analysis of hippocampal neuronal cell proliferation and activity, APP protein content, miR-129 expression and cell apoptosis by CCK-8 assay, Western blot method, MTT assay, qRT-PCR and flow cytometry. miR-129 expression of hippocampal neurons in IN group was lowest. Compared with IN and MO groups, SI group had significantly increased miR-129 level and reduced number of hippocampal neuron apoptosis (P < 0.05). Compared with IN group, MO group had significantly reduced cell apoptosis (P < 0.05). SI group had highest number of hippocampal neurons proliferation followed by IN group. SI group had highest OD value followed by MO group and IN group. The cell activity of SI group was higher than that of IN group and MO group (both P < 0.05). Compared with SI group, rat neuron activity in MO group was significantly higher than IN group (P < 0.05). The APP protein expression of hippocampal neuron cells in SI group was lowest followed by MO group and IN group (P < 0.05). In conclusion, the low miR-129 expression can inhibit the activity of hippocampal neurons possibly through up-regulation of APP protein content.

Mitochondrial homeostasis is involved in inhibiting hippocampus neuronal apoptosis during ZSWF ameliorate the cognitive dysfunction of SAMP8 mice

• ZSWF could inhibit neuronal apoptosis and improve cognitive ability of SAMP8 mice. • ZSWF could simultaneously regulate mitophagy and mitochondrial biogenesis. • ZSWF improve cognitive ability by maintaining neural mitochondrial homeostasis. ZSWF, a traditional Chinese medicine and nutritional supplement for nourishing kidney, presents ameliorating cognitive deficits effect. However, its mechanism remains unclear. Imbalance of neural mitochondrial homeostasis is a pathogenesis of AD. Considering “tonify kidney and nourish encephala” in traditional Chinese medicine theory is consistent with “mitochondria provides energy for neuros to maintain brain activity”, we hypothesized whether ZSWF could improve cognitive ability by regulating neuronal mitochondrial homeostasis. In this study, we firstly confirmed that ZSWF could improve the cognitive function of SAMP8 mice, alleviate histopathological lesion and inhibit neuro apoptosis. Then the components of ZSWF in cerebrospinal fluid and hippocampus were identified to fish their potential targets, which further indicated ZSWF might regulate mitochondrial homeostasis. Experimentally, we verified that ZSWF could reverse the neuronal mitochondrial loss of SAMP8 mice by upregulating PINK1, Parkin and PGC-1α to simultaneously regulate mitophagy and mitochondrial biogenesis to maintain mitochondrial homeostasis.

Dexmedetomidine reduces propofol-induced hippocampal neuron injury by modulating the miR-377-5p/Arc pathway

BackgroundPropofol and dexmedetomidine (DEX) are widely used in general anesthesia, and exert toxic and protective effects on hippocampal neurons, respectively. The study sought to investigate the molecular mechanisms of DEX-mediated neuroprotection against propofol-induced hippocampal neuron injury in mouse brains.MethodsHippocampal neurons of mice and HT22 cells were treated with propofol, DEX, and propofol+DEX. In addition, transfection of miR-377-5p mimics or inhibitors was performed in HT22 cells. Neuronal apoptosis was evaluated by a means of terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) or Hochest 33,258 staining; Arc positive expression in hippocampus tissues was detected using a microscope in immunohistochemistry assays; miRNA-377-5p expression was quantified by RT-qPCR; the protein levels of Arc, DNMT3A, and DNMT3B were determined using western blot; Cell Counting Kit-8 (CCK-8) assay was used to detect the viability and apoptotic rate of the neurons; methylation analysis in the miR-377-5p promoter was performed through methylated DNA immunoprecipitation (MeDIP) assay; dual luciferase reporter assay was performed to confirm whether Arc was under targeted regulation of miR-377-5p.ResultsIn the current study, both in vitro and in vivo, propofol treatment induced hippocampal neuron apoptosis and suppressed cell viability. DNMT3A and DNMT3B expression levels were decreased following propofol treatment, resulting in lowered methylation in the miR-377-5p promoter region and then enhanced expression of miR-377-5p, leading to a decrease in the expression of downstream Arc. Conversely, the expression levels of DNMT3A and DNMT3B were increased following DEX treatment, thus methylation in miR-377-5p promoter region was improved, and miR-377-5p expression was decreased, leading to an increase in the expression of downstream Arc. Eventually, DEX pretreatment protected hippocampal neurons against propofol-induced neurotoxicity by recovering the expression levels of DNMT3A, miR-377-5p, and Arc to the normal levels. Additionally, DNMT3A knockdown improved miR-377-5p expression but reduced Arc expression, and DNMT3A overexpression exerted the opposite effects. Dual luciferase reporter assay revealed a binding target between miR-377-5p and Arc 3’UTR. The neuroprotective effect of DEX against propofol-induced neuronal apoptosis was diminished after Arc knockdown. Silencing Arc independently triggered the apoptosis of HT22 cells, which was alleviated through transfection of miR-377-5p inhibitors.ConclusionsDEX reduced propofol-induced hippocampal neuron injury via the miR-377-5p/Arc signaling pathway.

Sulforaphane Attenuates Chronic Intermittent Hypoxia-Induced Brain Damage in Mice via Augmenting Nrf2 Nuclear Translocation and Autophagy.

Obstructive sleep apnea–hypopnea syndrome (OSAHS), typically characterized by chronic intermittent hypoxia (CIH), is associated with neurocognitive dysfunction in children. Sulforaphane (SFN), an activator of nuclear factor E2-related factor 2 (Nrf2), has been demonstrated to protect against oxidative stress in various diseases. However, the effect of SFN on OSAHS remains elusive. In this research, we investigated the neuroprotective role of SFN in CIH-induced cognitive dysfunction and underlying mechanisms of regulation of Nrf2 signaling pathway and autophagy. CIH exposures for 4 weeks in mice, modeling OSAHS, contributed to neurocognitive dysfunction, manifested as increased working memory errors (WMEs), reference memory errors (RMEs) and total memory errors (TEs) in the 8-arm radial maze test. The mice were intraperitoneally injected with SFN (0.5 mg/kg) 30 min before CIH exposure everyday. SFN treatment ameliorated neurocognitive dysfunction in CIH mice, which demonstrates less RME, WME, and TE. Also, SFN effectively alleviated apoptosis of hippocampal neurons following CIH by decreased TUNEL-positive cells, downregulated cleaved PARP, cleaved caspase 3, and upregulated Bcl-2. SFN protects hippocampal tissue from CIH-induced oxidative stress as evidenced by elevated superoxide dismutase (SOD) activities and reduced malondialdehyde (MDA). In addition, we found that SFN enhanced Nrf2 nuclear translocation to hold an antioxidative function on CIH-induced neuronal apoptosis in hippocampus. Meanwhile, SFN promoted autophagy activation, as shown by increased Beclin1, ATG5, and LC3II/LC3I. Overall, our findings indicated that SFN reduced the apoptosis of hippocampal neurons through antioxidant effect of Nrf2 and autophagy in CIH-induced brain damage, which highlights the potential of SFN as a novel therapy for OSAHS-related neurocognitive dysfunction.

ADSC-Exosomes Alleviate MTX-induced Rat Neuronal Damage by Activating Nrf2-ARE Pathway

The aim of this study was to analyze the efficacy and underlying mechanism of adipose-derived mesenchymal stem cell exosome (ADSC-exosomes)–mediated protection on methotrexate (MTX)–induced neuronal damage. We established a H2O2­induced oxidative stress model in vitro, as well as an MTX-induced neuronal damage rat model in vivo. We analyzed the effects of ADSC-exosomes on neuronal damage and Nrf2-ARE signaling pathway in rats and related mechanisms. The morphological and functional recovery of rat hippocampal neurons by ADSC-exosomes was examined by Nissl staining and modified neurological severity score (mNSS) score. The activation of Nrf2-ARE pathway effectively inhibited H2O2-induced oxidative stress. ADSC-exosomes treatment restored the activity of hippocampal neuronal cells, reduced ROS production, and inhibited hippocampal neuronal cells apoptosis. In in vivo experiments, ADSC­exosomes ameliorates MTX-induced hippocampal neuron damage by triggering Nrf2­ARE pathway, decreasing IL-6, IFN-, and TNF-a levels and TUNEL positive cells in hippocampus, and repairing hippocampal neuronal cell damage. ADSC­exosomes ameliorated MTX-induced neuronal damage and suppressed oxidative stress induced by neuronal damage through the activation of Nrf2-ARE signaling pathway.

Mechanism of paeoniflorin inhibiting apoptosis of hippocampal neurons of rats induced by lead acetate

Objective: To investigate the effect and underlying mechanism of paeoniflorin on hippocampal neuron apoptosis induced by lead acetate. Methods: In September 2020, primary hippocampal neuronal cells were isolated and cultured from fetal rats, and identified using cellular immunofluorescent. MTT assay was used to measure the cell viability to determine the concentration and time of lead acetate-induced hippocampal neuron apoptosis. MTT was also used to evaluate the effect of paeoniflorin concentration on the apoptosis of hippocampal neurons induced by lead acetate. According to the results, different concentrations of paeoniflorin were selected to intervene hippocampal neuron cells, after 24 h, lead acetate was added to the cells, meanwhile, blank and model groups were set up, the content of reactive oxygen species (ROS) , superoxide dismutase (SOD) , lactate dehydrogenase (LDH) , malondialdehyde (MDA) and Caspase-3 were measured. Extracellular signal regulated kinase (ERK) , phosphorylated ERK (p-ERK) , p38 mitogen -activated protein kinases (p38MAPK) , phosphorylated p38MAPK (p-p38MAPK) , c-Jun N-terminal kinase (JNK) and phosphorylated JNK (p-JNK) protein expression in hippocampal neuronal cells were determined by Western blotting. Results: The isolated and cultured hippocampal neurons were identified by immunofluorescence chemical staining and then treated with lead acetate, MTT results showed that lead acetate had the best toxicity effect when treated for 24 h at a concentration of 25 μmol/L. Paeoniflorin showed no cytotoxic effect on hippocampal neuronal cells when the concentrations below 80 μmol/L. Compared with the model group, the activity of hippocampal neuronal cells was significantly increased after treating with 20, 40 or 80 μmol/L paeoniflorin (P<0.05) . Compared with the blank group, the ROS activity, LDH release level, MDA content and caspase-3 content were significantly increased (P<0.01) , and the SOD activity was significantly decreased (P< 0.01) in the hippocampal neuronal cells of the model group. Compared with the model group, the ROS activity, LDH release level, MDA content and caspase-3 content were obviously decreased (P<0.05) , SOD activity was significantly increased (P <0.01) after hippocampal neuronal cells were treated with 40 or 80 μmol/L paeoniflorin. Relative to the model group, the ratio of p-ERK/ERK were significantly up-regulated (P<0.01) , while the ratios of p-p38MAPK/p38MAPK and p-JNK/JNK were significantly down-regulated after hippocampal neuronal cells were treated with 40 or 80 μmol/L paeoniflorin (P<0.05) . Conclusion: Paeoniflorin may down-regulate the expression of p-p38MAPK and p-JNK protein, up-regulate the expression of p-ERK protein, and inhibit the apoptosis of hippocampal neurons induced by lead acetate through the MAPK signaling pathway.

Magnesium-L-threonate exhibited a neuroprotective effect against oxidative stress damage in HT22 cells and Alzheimer’s disease mouse model

BACKGROUNDOxidative stress results in the production of excess reactive oxygen species (ROS) and triggers hippocampal neuronal damage as well as occupies a key role in the pathological mechanisms of neurodegenerative disorders such as Alzheimer’s disease (AD). A recent study confirmed that magnesium had an inhibitory effect against oxidative stress-related malondialdehyde in vitro. However, whether Magnesium-L-threonate (MgT) is capable of suppressing oxidative stress damage in amyloid β (Aβ)25-35-treated HT22 cells and the AD mouse model still remains to be investigated.AIMTo explore the neuroprotective effect of MgT against oxidative stress injury in vitro and in vivo, and investigate the mechanism.METHODSAβ25-35-induced HT22 cells were preconditioned with MgT for 12 h. APPswe/PS1dE9 (APP/PS1) mice were orally administered with MgT daily for 3 mo. After MgT treatment, the viability of Aβ25-35-treated HT22 cells was determined via conducting cell counting kit-8 test and the cognition of APP/PS1 mice was measured through the Morris Water Maze. Flow cytometry experiments were applied to assess the ROS levels of HT22 cells and measure the apoptosis rate of HT22 cells or hippocampal neurons. Expression of B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X (Bax), hypoxia-inducible factor (HIF)-1α, NADPH oxidase (NOX) 4, Aβ1-42 and phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt) pathway proteins was quantified by Western blot.RESULTS In vitro data confirmed that Aβ25–35-induced HT22 cells had a significantly lower cell viability, higher ROS level and higher apoptosis rates compared with those of control cells (all P < 0.001). MgT prevented the Aβ25-35-triggered oxidative stress damage by elevating viability and decreasing ROS formation and apoptosis of HT22 cells (all P < 0.001). APP/PS1 mice exhibited worse cognitive performance and higher apoptosis rate of hippocampal neurons than wild-type (WT) mice (all P < 0.01). Meanwhile, significant higher expression of Aβ1-42 and NOX4 proteins was detected in APP/PS1 mice than those of WT mice (both P < 0.01). MgT also ameliorated the cognitive deficit, suppressed the apoptosis of hippocampal neuron and downregulated the expression of Aβ1-42 and NOX4 proteins in APP/PS1 mouse (all P < 0.05). Moreover, MgT intervention significantly downregulated HIF-1α and Bax, upregulated Bcl-2 and activated the PI3K/Akt pathway both in vitro and in vivo (all P < 0.05).CONCLUSIONMgT exhibits neuroprotective effects against oxidative stress and hippocampal neuronal apoptosis in Aβ25-35-treated HT22 cells and APP/PS1 mice.

Quantitative analysis of PACAP-38 and amyloid beta composition using a dual reaction in reduced graphene oxide biosensor to verify the neuroprotective role of PACAP-38

Here, we developed a sophisticated reduced graphene oxide (rGO) sensor capable of monitoring the progress of Alzheimer’s disease by quantifying the concentration of amyloid beta (Aβ) and pituitary adenylate cyclase activating polypeptide 38 (PACAP-38). Western blot analysis following induction of apoptosis in mouse hippocampal neurons with TNF-α demonstrated that PACAP-38/Aβ binding inhibited neural cell apoptosis. To verify the direct binding of PACAP-38 to Aβ, a simulated docking model was generated, and binding affinities were quantified using surface plasmon resonance (SPR). After PACAP-38-Aβ binding was confirmed, the properties of each protein were evaluated by the rGO sensor based on differences in their charge to determine the PACAP-38: Aβ ratio. Based on the observed changes in resistance obtained by measuring each protein monomer, expected resistance change values were derived for each binding reaction and subsequent accumulation of PACAP-38 and Aβ. Subsequently, rGO sensor measured changes in resistance following binding and accumulation of each protein. The resistance change values were compared with the expected values to verify the accuracy of the sensor for quantifying accumulated proteins. The accuracy of the sensor was determined based on deviation of the sensor output within its dynamic range. The significance was expressed based on the equation for significance values and was confirmed to be as high as 96% between expected and measured values. Collectively, our results verify the neuroprotective role of PACAP-38 and proposes rGO sensor as a potential tool for early diagnosis of as well as monitoring the progression of Alzheimer’s disease.

Statement of Retraction: NF-κB signaling pathway inhibition suppresses hippocampal neuronal apoptosis and cognitive impairment via RCAN1 in neonatal rats with hypoxic-ischemic brain damage

This article refers to:RETRACTED ARTICLE: NF-κB signaling pathway inhibition suppresses hippocampal neuronal apoptosis and cognitive impairment via RCAN1 in neonatal rats with hypoxic-ischemic brain damage

Paeoniflorin ameliorates cognitive impairment in Parkinson\u2019s disease via JNK/p53 signaling

Paeoniflorin (PF) has numerous benefits, including anti-inflammatory and anti-apoptosis effects. However, it is not clear if it has neuroprotective effects against cognitive impairment (CI) in Parkinson’s disease (PD). Through network pharmacology, we identified probable targets as well as signal pathways through which PF might affect CI in PD. Then, we experimentally validated our findings. The core genes of the protein-protein interactions (PPI) network include MAPK8 (JNK), TP53, CASP3 (caspase-3), postsynaptic density protein-95 (PSD-95) and synaptophysin (SYN). Pathway enrichment analysis revealed that genes involved in apoptosis and mitogen-activated protein kinase (MAPK) signaling were significantly enriched. Because JNK is a key mediator of p53-induced apoptosis, we wondered if JNK/p53 pathway influences the effects of PF against apoptosis in mouse model of PD. Molecular docking analysis showed that PF had good affinity for JNK/p53. The results of the experiments indicated that PF ameliorated behavioral impairments and upregulated the expression of the dopamine (DA) neurons, suppressed cell apoptosis in substantia nigra pars compacta (SNpc) of PD. Additionally, PF improved 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neuronal injury by inhibiting apoptosis in hippocampal neurons of the CA1 and CA3, and upregulating PSD-95 as well as SYN protein levels. Similar protective effects were observed upon JNK/p53 pathway inhibition using SP600125. Overall, PF improved CI in PD by inhibiting JNK/p53 pathway.