SAT1 Knockdown Decreases Glutamate-Induced Oxidative Stress, Ferroptosis, and Apoptosis in HT22 Cells via Activating the Nrf2/ARE Pathway.

This study is aimed at exploring the potential of isorhamnetin in protection against diabetes-exacerbated ischemia/reperfusion-induced brain injury and elucidating its action mechanism. After establishment of the model of high glucose (HG)-aggravated oxygen-glucose deprivation and reoxygenation (OGD/R), HT22 cell viability was detected by CCK-8. Lactate dehydrogenase (LDH) activity, casapase-3 activity, and oxidative stress-related markers in HT22 cells were detected by corresponding commercial kits. The apoptosis of HG-treated HT22 cells following OGD/R was observed with TUNEL staining. The level of pro-inflammatory cytokines was examined by ELISA. The expression of Akt/SIRT1/Nrf2/HO-1 signaling-related proteins was assayed by Western blot. The results showed that HG noticeably worsened the OGD/R-induced apoptosis of HT22 cells. Isorhamnetin relieved the HG-aggravated OGD/R-induced apoptosis, inflammatory response, and oxidative stress of HT22 cells. Isorhamnetin alleviated the HG-aggravated OGD/R injury in HT22 cells through Akt/SIRT1/Nrf2/HO-1 signaling pathway. Meanwhile, treatment with Akt inhibitor LY294002 reversed the protective effects of isorhamnetin against HG-aggravated OGD/R injury in HT22 cells. In a conclusion, Isorhamnetin alleviates HG-aggravated OGD/R in HT22 hippocampal neurons through Akt/SIRT1/Nrf2/HO-1 signaling pathway.

Exosome-like nanovesicles (ELNs) derived from plants are nanoscale vesicles isolated from edible plant sources. Lycium ruthenicum Murray (LRM) has garnered growing attention for its dietary value and therapeutic benefits. In this study, a PEG6000-based method was developed to isolate LRM-ELNs. Response surface methodology (RSM) was used to optimize the extraction conditions to obtain the optimal extraction efficiency. When PEG6000 concentration was at 11.93%, relative centrifugal force was 9720 g, and incubation time was 21.12 h, the maximum LRM-ELN yield was 4.24 g/kg. This optimization process yielded LRM-ELNs with a particle size of 114.1 nm and a surface charge of -6.36 mV. Additionally, LRM-ELNs mitigated Aβ-induced apoptosis in HT22 cells by enhancing mitochondrial membrane potential (MMP), lowering the Bax/Bcl-2 ratio, and reducing Cleaved Caspase-3 expression. Furthermore, LRM-ELNs alleviated Aβ-induced oxidative stress in HT22 cells by promoting the nuclear translocation of Nrf2 and upregulating the expression of HO-1 and NQO1. These findings indicate that LRM-ELNs exert protective effects against Aβ-induced damage in HT22 cells and may be considered as a potential dietary supplement for Alzheimer's disease prevention.

Glutamate (Glu) possesses functional significance concerning neurological disorders by producing neurotoxicity as a major excitatory amino acid neurotransmitter. Sestrin2 (SESN2) has been affirmed to elicit wide neuroprotective properties as a highly conserved stress-responsive protein. Therefore, this project sets out to ascertain the impacts of SESN2 on Glu neurotoxicity and the concealed operating mechanism. Cell counting kit-8 (CCK-8) assay, lactate dehydrogenase (LDH) assay kit, and Western blot estimated cell viability, cytotoxicity, and SESN2 expression. Commercial kits and fluorescence probes were employed to assess the degree of oxidative stress. The apoptotic changes were evaluated by terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL) and Western blot. Mitochondrial function was measured by 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanine iodide (JC-1) staining, MitoSOX staining, and Western blot analysis of mitophagy-related proteins and immunofluorescence. Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) pathway-related proteins were also examined with Western blot. SESN2 expression was elevated in HT-22 cells upon stimulation with Glu. SESN2 upregulation reduced the viability loss, LDH release, oxidative stress, and apoptosis in HT-22 cells imposed by the Glu challenge, while a contrary trend was observed when SESN2 was downregulated. Moreover, hyperexpressed SESN2 activated the Keap1-Nrf2 pathway to promote mitophagy in Glu-exposed HT-22 cells. Deletion of Nrf2 partly abolished the effects of SESN2 elevation on the mitophagy, and mitophagy blocker Mdivi-1 partly reverted the influences of SESN2 overexpression on the viability, LDH release, oxidative stress, and apoptosis in Glu-stimulated HT-22 cells. SESN2 might mediate mitophagy via the Keap1-Nrf2 pathway to confer neuroprotection toward Glu-provoked toxicity.

Stroke is a prevalent and debilitating neurodegenerative condition. Ginsenoside Rg1 has demonstrated neuroprotective properties in the context of stroke. The upregulation of chemokine-like factor 1 (CKLF1) observed in ischemic stroke positions CKLF1 as a promising therapeutic target. However, limited research has explored whether Rg1 can mitigate oxygen-glucose deprivation/reoxygenation (OGD/R)-induced apoptosis in HT22 cells through the modulation of CKLF1. In this study, Na2S2O4 was used to treat HT22 cells to establish the OGD/R model. The effects of different concentrations of Rg1 on cell viability were firstly determined by CCK-8 assay to determine its safe administration range. Subsequently, the level of oxidative stress was assessed by detecting LDH release and antioxidant indexes (CAT, SOD, MDA). Western blotting was used to analyse the expression of CKLF1 and apoptosis-related proteins, and TUNEL staining was used to quantify the apoptosis rate. To explore the cell-cell interactions, a Transwell co-culture system of HT22 and BV-2 cells was established. In this study, the optimal parameters for the OGD/R model were determined: 25mmol/L Na2S2O4 treatment for 2.5h followed by 2.5h of reoxygenation, and a cell inoculation density of 1 × 105 cells/mL for 1 day of culture. Based on the safety assessment, 5, 25, and 50μmol/L Rg1 were selected for intervention. Rg1 significantly decreased LDH release (P ≤ 0.05) and MDA content (P ≤ 0.05) and alleviated oxidative stress. Western blotting showed that Rg1 dose-dependently downregulated the expression of CKLF1 (P ≤ 0.05) and inhibited Caspase-3 and other apoptotic protein activation. In the HT22/BV-2 co-culture system, Rg1 inhibited microglia activation, as shown by reduced NO and IL-1β secretion (P ≤ 0.05). Rg1 attenuates OGD/R injury, reduces oxidative stress and apoptosis in HT22 cells by inhibiting CKLF1 expression and alleviates the inflammatory response in activated BV-2 cells, showing therapeutic potential.

The factors influencing hippocampal aging are complex, and it remains challenging to identify effective anti-aging drugs and reveal pharmacological mechanisms. This study investigates the effects of autophagy mediated by the SIRT1/FoxO1 signaling pathway on resveratrol resistance to H2O2-induced aging and apoptosis in mouse hippocampal neurons. HT22 cells were treated with resveratrol and H2O2 to evaluate the effects of resveratrol on H2O2-induced aging and apoptosis. The levels of P21, P53, BAX, Cleaved Caspase-3, and Bcl-2 were measured to estimate aging and apoptosis. Western blot, immunofluorescence assays, and transmission electron microscopy observation were used to detect the regulation of resveratrol on autophagy. 3-Methyladenine was used to block autophagy, and EX-527 was used to inhibit SIRT1. The changes of autophagy factors and the levels of SIRT1/FoxO1 signaling pathway were assayed. H2O2 treatment induced aging in HT22 cells, manifesting increased levels of P21 and P53 and decreased cell viability. H2O2 treatment aggravated apoptosis, showing increased levels of BAX and Cleaved Caspase-3, decreased levels of Bcl-2, and increased apoptotic cells. Resveratrol alleviated aging and apoptosis in H2O2-induced HT22 cells. Mechanically, resveratrol activated autophagy by up-regulating the levels of LC3B Ⅱ/Ⅰ and Beclin1 and down-regulating P62 against aging and apoptosis, which was abolished by 3-Methyladenine. Western blot results showed resveratrol activated SIRT1/FoxO1 signaling pathway which was related to regulation of autophagy. EX-527 treatment suggested resveratrol could not activate autophagy when the SIRT1/FoxO1 signaling pathway was blocked. These findings indicated that resveratrol activated autophagy via SIRT1/FoxO1 signaling pathway to protect against H2O2-induced aging and apoptosis in HT22 cells.

Intermittent hypoxia (IH) is the primary pathological manifestation of obstructive sleep apnea (OSA) and the main cause of OSA-induced cognitive impairment. Hippocampal neurons are considered to be critical cells affected by IH. Transforming growth factor-β3 (TGF-β3) is a cytokine with a neuroprotective effect, which plays a crucial role in resisting hypoxic brain injury, while its role in IH-induced neuronal injury is still unclear. Here, we aimed to clarify the mechanism of TGF-β3 protecting IH-exposed neurons by regulating oxidative stress and secondary apoptosis. Morris water maze results revealed that IH exposure was unable to affect the vision and motor ability of rats, but significantly affected their spatial cognition. Second-generation sequencing (RNA-seq) and subsequent experiments supported that IH decreased TGF-β3 expression and stimulated reactive oxygen species (ROS)-induced oxidative stress and apoptosis in rat hippocampus. In vitro, IH exposure significantly activated oxidative stress within HT-22 cells. Exogenous administration of Recombinant Human Transforming Growth Factor-β3 (rhTGF-β3) prevented ROS surge and secondary apoptosis in HT-22 cells caused by IH, while TGF-β type receptor I (TGF-βRI) inhibitor SB431542 blocked the neuroprotective effect of rhTGF-β3. Nuclear factor erythroid 2-related factor 2 (Nrf-2) is a transcription factor preserving intracellular redox homeostasis. rhTGF-β3 improved the nuclear translocation of Nrf-2 and activated downstream pathway. However, Nrf-2 inhibitor ML385 suppressed the activation of the Nrf-2 mechanism by rhTGF-3 and restored the effects of oxidative stress damage. These results indicate that TGF-β3 binding to TGF-βRI activates the intracellular Nrf-2/KEAP1/HO-1 pathway, reduces ROS creation, and attenuates oxidative stress and apoptosis in IH-exposed HT-22 cells.

Neuronal disease is caused by neuronal cell damage, and a high concentration of glutamate causes neuronal cell death. The purpose of this experiment was to confirm the protective effect of Oleiferin F (OF) on glutamate-induced apoptosis in HT22 cells. Oleiferin F inhibited the death of glutamate-induced HT22 cells in a dose-dependent manner as confirmed by annexin V/propidium iodide (PI) double staining. Oleiferin F reduced disruption of the mitochondrial membrane potential (ΔΨm), p53 expression, the Bax/Bcl-2 expression ratio and mitochondrial apoptosis-inducing factor (AIF) protein release. Oleiferin F also reduced levels of the cleaved form of caspase pathway proteins (PARP, caspase-9, caspase-3), which lead to apoptosis. These results reveal the mechanism underlying the neuroprotective effect of Oleiferin F in HT22 cells. Oleiferin F may be useful in preventing or treating neurological diseases.

Sevoflurane causes neural injury by promoting apoptosis and oxidative stress. Reactive oxygen species modulator 1 (ROMO1) regulates apoptosis and oxidative stress, while its role in sevoflurane-induced neural injury remains unclear. This study intended to investigate the effect of ROMO1 knockdown on viability, apoptosis, and oxidative stress in sevoflurane-treated HT22 cells and its downstream pathway. HT22 cells were untreated (blank control), or treated with 1%, 2%, and 4% sevoflurane, respectively. Moreover, HT22 cells were transfected with siROMO1 small interfering RNA (siROMO1) or negative control siRNA (siNC) and then stimulated with 4% sevoflurane for further assays. Sevoflurane dose-dependently decreased cell viability and increased apoptosis rate versus blank control in HT22 cells. Sevoflurane elevated reactive oxygen species (ROS) fluorescence intensity, malondialdehyde (MDA), and lactate dehydrogenase (LDH) release, while reducing superoxide dismutase (SOD) activity in a dose-dependent manner versus blank control in HT22 cells. It also dose-dependently increased the relative mRNA and protein expressions of ROMO1 versus blank treatment in HT22 cells. Moreover, siROMO1 plus 4% sevoflurane increased cell viability, while decreasing apoptosis rate, ROS fluorescence intensity, MDA, and LDH release versus siNC plus 4% sevoflurane in HT22 cells. siROMO1 plus 4% sevoflurane elevated the phosphorylation of protein kinase B (AKT) versus siNC plus 4% sevoflurane in HT22 cells. ROMO1 inhibition reverses sevoflurane-induced neural injury by reducing apoptosis and oxidative stress in HT22 cells. The results indicate that ROMO1 may be a potential target for the management of sevoflurane-induced neural injury.

Sevoflurane (Sev) is a commonly used inhalation anaesthetic that has been shown to cause hippocampus dysfunction through multiple underlying molecular processes, including mitochondrial malfunction, oxidative stress and inflammation. Dihydromyricetin (DHM) is a 2,3-dihydroflavonoid with various biological properties, such as anti-inflammation and anti-oxidative stress. The purpose of this study was to investigate the effect of DHM on Sev-induced neuronal dysfunction. HT22 cells were incubated with 10, 20 and 30 μM of DHM for 24 h, and then stimulated with 4% Sev for 6 h. The effects and mechanism of DHM on inflammation, oxidative stress and mitochondrial dysfunction were explored in Sev-induced HT22 cells by Cell Counting Kit-8, flow cytometry, enzyme-linked immunosorbent assay, reverse transcription-quantitative polymerase chain reaction, colorimetric detections, detection of the level of reactive oxygen species (ROS), mitochondrial ROS and mitochondrial membrane potential (MMP), immunofluorescence and western blotting. Our results showed that DHM increased Sev-induced cell viability of HT22 cells. Pretreatment with DHM attenuated apoptosis, inflammation, oxidative stress and mitochondrial dysfunction in Sev-elicited HT22 cells by remedying the abnormality of the indicators involved in these progresses, including apoptosis rate, the cleaved-caspase 3 expression, as well as the level of tumour necrosis factor α, interleukin (IL)-1β, IL-6, malondialdehyde, superoxide dismutase, catalase, ROS, mitochondrial ROS and MMP. Mechanically, pretreatment with DHM restored the Sev-induced the expression of SIRT1/FOXO3a pathway in HT22 cells. Blocking of SIRT1 counteracted the mitigatory effect of DHM on apoptosis, inflammation, oxidative stress and mitochondrial dysfunction in Sev-elicited HT22 cells. Collectively, pretreatment with DHM improved inflammation, oxidative stress and mitochondrial dysfunction via SIRT1/FOXO3a pathway in Sev-induced HT22 cells.

Epilepsy refers to a diverse group of neurological pathologies, coupled with a significant worldwide impact. Azilsartan, an angiotensin receptor blocker, is broadly applied as an antihypertensive medication. Considering that the neuroprotective potential of Azilsartan has been newly documented, our work was committed to characterizing the association of Azilsartan with epilepsy and its possible mechanism. First, mice hippocampal neuron (HT-22) cells were exposed to kainic acid (KA) with or without Azilsartan treatment. Cell Counting Kit 8 (CCK8) method assessed the viability of KA-treated HT-22 cells. Flow cytometry assay was employed to detect cellular apoptotic capacity. DCF-DA fluorescent staining, JC-1 probe, and related assay kits were used to estimate mitochondrial oxidative stress. Western blotting examined the expression of Sirtuin 3 (Sirt3), superoxide dismutase 2 (Sod2), and apoptosis-related proteins. Additionally, Sirt3 was silenced to analyze whether the protective effect of Azilsartan on KA-induced damage of HT-22 cell damage was achieved by regulating Sirt3. Results indicated that KA intervention concentration-dependently triggered the viability loss, apoptosis, and mitochondrial damage in HT-22 cells. Azilsartan treatment protected against KA-induced HT-22 cell injury by elevating the viability, reducing the apoptosis, and attenuating mitochondrial damage. Besides, Azilsartan administration activated Sirt3 and Sod2 expression in KA-stimulated HT-22 cells, and Sirt3 depletion partially blocked the impacts of Azilsartan on Sirt3/Sod2 pathway, mitochondrial damage, viability, and apoptosis in HT-22 cells exposed to KA. Collectively, Azilsartan might act as a neuroprotective agent in treating epilepsy through the activation of Sirt3/Sod2 pathway.

Excessive glutamate levels induce oxidative stress, resulting in neuronal damage, and cell death. While natural antioxidants show promise for neuroprotection, their effectiveness in the central nervous system (CNS) is limited by the blood -brain barrier. Lutein, a neuroprotective carotenoid, has gained attention for its ability to traverse this barrier and accumulate in various brain regions. This study aimed to elucidate the mechanisms underlying the protective effects of lutein against glutamateinduced cell death in HT22 cells. HT22 cells were treated with lutein (1.25-20 μM) for 24 hours. Cell viability, ROS levels, apoptosis, and mitochondrial membrane potential were assessed following lutein pretreatment and glutamate exposure. Protein expression of apoptotic markers was analyzed using Western blotting. Lutein effectively attenuated glutamate-induced apoptosis due to its antioxidant properties. Additionally, lutein inhibited glutamate-induced mitochondrial-mediated apoptosis. We observed that lutein modulated the nuclear translocation of nuclear factor erythroid 2 -related factor 2 (Nrf2) and upregulated the expression of heme oxygenase-1 (HO-1). Inhibition of HO-1 by tin protoporphyrin (SnPP), a synthetic inhibitor, weakened the protective effect of lutein. Furthermore, we demonstrated that lutein prevented the aberrant activation of MAPKs induced by glutamate, including ERK1/2, p38, and JNK, thereby conferring oxidative protection. Our study highlights the potent antioxidant properties of lutein, which effectively safeguards against glutamate-induced mitochondrial apoptotic cell death through the Nrf2/HO-1 signaling pathway and inhibition of MAPK activation. These findings demonstrate that lutein exerts a neuroprotective effect against glutamate-induced neuronal cell damage.

Aconitine induces cell apoptosis via mitochondria and death receptor signaling pathways in hippocampus cell line

BackgroundIntracerebral hemorrhage (ICH) is a severe subtype of stroke with high mortality and morbidity. Serpin Family E Member 1 (SERPINE1) has been documented to be upregulated following ICH, however, the participation of SERPINE1 in the development of ICH has never been studied.MethodsHemin was utilized to develop an in vitro model of ICH. Gene levels were evaluated by the use of quantitative reverse transcription polymerase chain reaction, Western blot, as well as enzyme-linked immunoassay assay. The activity of caspase-3 was determined using a commercial kit. Cell viability and apoptosis were assessed using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and Terminal deoxynucleotidyl transferase (TdT) d UTP Nick-End Labeling assay.ResultsSERPINE1 was upregulated in hemin-treated HT22 cells. Silencing of SERPINE1 attenuated hemin-induced inhibition of cell viability. Moreover, knockdown of SERPINE1 repressed hemin-induced apoptosis in HT22 cells, as evidenced by the decrease in the number of TUNEL positive cells, caspase-3 activity, and Bax expression, and the increase in Bcl-2 expression. Meanwhile, knockdown of SERPINE1 repressed hemin-induced inflammation in HT22 cells, as indicated by reduced levels of tumor necrosis factor-α, interleukin-6 (IL-6), IL-1β, and inducible nitric oxide synthase. We also found that transforming growth factor-beta 1 (TGF-β1) induced SERPINE1 expression in a dose-dependent manner. Besides, SERPINE1 knockdown attenuated the effects of TGF-β1 on hemin-induced neuronal damage.ConclusionTGF-β1-induced SERPINE1 activation exacerbated hemin-induced apoptosis and inflammation in HT22 cells, manifesting a novel mechanism for ICH progression.

miR-382-3p can regulate apoptosis through multiple pathways, but the mechanism remains unknown. In this experiment, we explored whether miR-382-3p can modulate the N-methyL-D-aspartate (NMDA)- induced HT22 cell apoptosis by regulating the RhoC/ROCK1 signaling pathway. An excitatory neurotoxicity model of HT22 cells was induced in vitro with 2 mmol/L NMDA. The cells were divided into normal control, NMDA-induced, NMDA + miR-382-3p mimic, and NMDA + miR-382-3p inhibitor groups. The 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) method, Real-time PCR, Western blot, and flow cytometry were performed to investigate the mechanisms. The results found that NMDA can increase the oxidative stress of HT22 cells in a dose-dependent manner, downregulate the expression of miR-382-3p, upregulate the expression of mRNA and protein abundance of ROCK1 and RhoC, increase the expression levels of proapoptotic proteins Bax, Caspase-3, and Caspase-9, increase the apoptosis of HT22 cells, and reduce the activity and survival rate of HT22 cells. Compared with the NMDA-induced group, the miR-382-3p mimic-transfected HT22 cells increased the expression of miR- 382-3p, reduced the expression of the mRNA and protein abundance of ROCK1 and RhoC, inhibited the expression of proapoptotic proteins Bax, Caspase-3, and Caspase-9, reduced the apoptosis of HT22 cells, and increased the activity and survival rate of HT22 cells. The results suggest that increasing the expression of miR-382-3p can inhibit the activity of the RhoC/ROCK1 signaling pathway, reduce the expression of proapoptotic proteins, reduce the oxidative stress and apoptosis of HT22 cells, and increase the activity and survival rate of HT22 cells.

This project is conceived to reveal the role of lidocaine in the process of Alzheimer's disease (AD) and its possible downstream targets. After the employment of AD cell model in mice hippocampal neuronal HT-22 cells in the presence of amyloid-β1-42 (Aβ1-42), Cell Counting Kit-8 method investigated cell viability. Oxidative damage was assayed based on a dichloro-dihydro-fluorescein diacetate fluorescent probe and commercially available kits. The 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanine iodide fluorescent probe estimated mitochondrial function. Terminal-deoxynucleotidyl transferase mediated nick end labeling, western blotting, and immunofluorescence appraised the apoptotic level. Western blot also ascertained the alternations of nerve growth factors (NGF)-protein kinase B (Akt) pathway-related proteins. Aβ1-42 concentration dependently triggered the viability loss, oxidative damage, and apoptosis in HT-22 cells. Lidocaine promoted the viability and reduced the mitochondrial impairment and mitochondria-dependent apoptosis in Aβ1-42-treated HT-22 cells in a concentration-dependent manner. Besides, lidocaine activated the NGF-Akt pathway and NGF absence blocked NGF-Akt pathway, aggravated mitochondrial dysfunction as well as mitochondria-dependent apoptosis in lidocaine-administrated HT-22 cells in response to Aβ1-42. Altogether, these observations concluded that lidocaine might stimulate NGF-Akt pathway to confer protection against mitochondrial impairment and apoptosis in Aβ1-42-mediated cellular model of AD.