Mitochondrial Apoptotic Pathway Research Articles

Indoxyl sulfate induces apoptosis in mononuclear blood cells via mitochondrial pathway

The consequence of chronic kidney disease is the accumulation of metabolic products called uremic toxins in the body. Indoxyl sulfate (IS) is a toxin with a high affinity for proteins. This study focuses on the deleterious effect of IS, especially apoptosis induction, in mononuclear blood cells (MNCs). Thus, in MNCs treated with IS at three different concentrations for 24 h, the survival, mitochondrial potential, caspases activity and expression, Bcl-2 and Bax protein expression, DNA damage, and PARP degradation were estimated. The study showed a decrease in survival and mitochondrial potential of MNCs treated with IS compared to the control. IS increased the activity of caspase 2-, 3-, 9-, and the expression of caspase 3-, and 9- in MNCs but does not affect the activity of caspase 6- and 8. The treatment of MNCs with IS also increased DNA damage and degradation of PARP. Indoxyl sulfate significantly influences the expression of Bcl-2 and Bax proteins. Indoxyl sulfate induces the programmed death of MNCs through the intrinsic mitochondrial apoptotic pathway. The observed cellular changes are mostly dose-dependent.

Pyrroloquinoline Quinone (PQQ) Improves Long-term Survival of Fat Grafts by Alleviating Oxidative Stress and Promoting Angiogenesis During the Early Phase After Transplantation.

Reducing absorption after autologous fat grafting is a current challenge. Pyrroloquinoline quinone (PQQ) is the strongest known catalyst of redox reactions, which can scavenge reactive oxygen species (ROS) and alleviate oxidative stress. The aim of this study was to establish an in vivo model of PQQ-assisted lipotransfer and clarify the role of PQQ in reducing oxidative stress, alleviating apoptosis, and promoting angiogenesis during the acute hypoxic phase after grafting. In addition the study was performed to assess whether this intervention would have a positive effect on the improvement of long-term volume retention. Different concentrations of PQQ (low: 10 μM, medium: 100 μM, and high: 1000 μM) were mixed with human adipose tissue and transplanted subcutaneously into nude mice. Meanwhile, a control group of phosphate-buffered saline in an equal volume to PQQ was set up. On the third day after grafting, whole mount fluorescence staining was applied to detect ROS, mitochondrial membrane potential (MMP), apoptosis, adipocyte activity, and angiogenesis. Graft volume retention rate and electron microscopic morphology were evaluated at the third month. Immunohistochemistry and polymerase chain reaction (PCR) were further employed to elucidate the mechanism of action of PQQ. PQQ-assisted fat grafting improved the long-term volume retention, promoted the quality and viability of the adipose tissue, and reduced the level of fibrosis. The underlying mechanism of PQQ assisted in scavenging the accumulated ROS, restoring MMP, enhancing adipocyte viability, alleviating tissue apoptosis, and promoting timely angiogenesis during the hypoxia stress phase. The most effective concentration of PQQ was 100 μM. Immunohistochemistry and PCR experiments confirmed that PQQ reduced the expression of Bax and cytochrome c in the mitochondrial apoptotic pathway and increased the level of the antiapoptotic molecule Bcl-2. PQQ could improve the long-term survival of adipocytes by alleviating hypoxic stress and promoting timely angiogenesis in the early phase following lipotransfer.

5-Methoxyisatin N(4)-Pyrrolidinyl Thiosemicarbazone (MeOIstPyrd) Restores Mutant p53 and Inhibits the Growth of Skin Cancer Cells, In Vitro.

A series of novel thiosemicarbazone derivatives containing 5-methoxy isatin were designed and synthesized with modification on N(4) position. Derivatives considering structure-activity relationship have been designed and synthesized by condensing thiosemicarbazide with 5-methoxy isatin. The synthesized compounds were characterized by elemental analysis, FT-IR spectroscopy, UV-visible spectroscopy, NMR (1H, 13C) spectroscopy, mass spectrometry, and a single-crystal study. Biological evaluation of the synthesized compounds revealed that MeOIstPyrd is the most promising compound against skin cancer cell line, A431, with an IC50 value of 0.9 μM. In addition, MeOIstPyrd also exhibited low toxicity against the normal human fibroblast and the human embryonic kidney 293 cell line, HLF-1, and HEK293, respectively. Furthermore, the mechanistic study revealed that MeOIstPyrd efficiently inhibited cell proliferation, migration, and spheroid formation by activating the mitochondrial intrinsic apoptotic pathway. MeOIstPyrd also induces DNA damage and activates p53 irrespective of the p53 status. It increases the half-life of p53 and stabilizes p53 by phosphorylating it at ser15. Moreover, MeOIstPyrd was found to bind to MDM2 in the p53 sub-pocket and, therefore, block p53-MDM2 interaction. Our result exhibited potential anticancer activity of MeOIstPyrd in the A431 cell line and its ability in restoring mutant p53, which is an interesting and promising strategy for cancer therapeutics.

Multicolor-Encoded DNA Framework Enables Specific and Amplified In Situ Detection of the Mitochondrial Apoptotic Signaling Pathway.

Monitoring the molecular activation networks of cellular processes through fluorescence imaging to accurately elucidate the signaling pathways of mitochondrial apoptosis and the regulation of upstream and downstream molecules remains a current major challenge. In this work, a multicolor-encoded tetrahedral DNA framework (meTDF) carrying two pairs of catalytic hairpins is synthesized to monitor the intracellular upstream manganese superoxide dismutase (MnSOD) mRNA and the downstream cytochrome c (Cyt c) molecules for specific and sensitive detection of the mitochondrial apoptotic signaling pathway. These two types of molecules can trigger catalytic hairpin assembly (CHA) reactions with accelerated reaction kinetics for the hairpin pairs confined on meTDF to show highly amplified fluorescence for sensitive and simultaneous detection of MnSOD mRNA and Cyt c with detection limits of 3.7 pM and 0.23 nM in vitro, respectively. Moreover, the high stability and biocompatibility of the designed meTDF can facilitate efficient delivery of the probes into cells to monitor intracellular MnSOD mRNA and Cyt c for specific detection of the mitochondrial apoptosis pathway regulated by different drugs. With the successful demonstration of their robust capability, the meTDF nanoprobes can thus open new opportunities for detecting cell apoptotic mechanisms for studying the corresponding apoptotic signaling pathways and for screening potential therapeutic drugs.

Phosphate-induced activation of VEGFR2 leads to caspase-9-mediated apoptosis of hypertrophic chondrocytes

Low circulating phosphate (Pi) leads to rickets, characterized by expansion of the hypertrophic chondrocytes (HCs) in the growth plate due to impaired HC apoptosis. Studies in HCs demonstrate that Pi activates the Raf/MEK/ERK1/2 and mitochondrial apoptotic pathways. To determine how Pi activates these pathways, a small-molecule screen was undertaken to identify inhibitors of Pi-induced ERK1/2 phosphorylation in HCs. Vascular endothelial growth factor receptor 2 (VEGFR2) was identified as a target. Invitro studies in HCs demonstrate that VEGFR2 inhibitors block Pi-induced pERK1/2 and caspase-9 cleavage. Like Pi, rhVEGF activates ERK1/2 and caspase-9 in HCs and induces phosphorylation of VEGFR2, confirming that Pi activates this signaling pathway in HCs. Chondrocyte-specific depletion of VEGFR2 leads to an increase in HCs, impaired vascular invasion, and a decrease in HC apoptosis. Thus, these studies define a role for VEGFR2 in transducing Pi signals and mediating its effects on growth plate maturation.

Icariin prevents depression-like behaviors in chronic unpredictable mild stress-induced rats through Bax/cytoplasm C/caspase-3 axis to alleviate neuronal apoptosis.

Major depressive disorder (MDD) affects approximately 16% of the global population. Our previous study has demonstrated that icariin (ICA) exhibits anti-depressant activity by increasing the expression of Brain-Derived Neurotrophic Factor(BDNF) in a rat model of chronic unpredictable mild stress (CUMS). In this study, we investigated whether and how ICA can prevent CUMS-induced depression-like behaviors in rats by modulating hippocampus neuronal apoptosis. Forty male rats were randomly divided into control, CUMS, CUMS-fluoxetine (Flx) (10 mg/kg), and CUMS-ICA (20 mg/kg) groups. Behavior tests including sucrose preference test (SPT), open field test (OFT), elevated plus-maze (EPM), and forced swimming tests (FST) were performed. The Nissl staining and TUNNEL assay were used to determine neuronal apoptosis. Subsequently, expression of the glucocorticoid receptor (GR), Bcl-2, cytochrome C, caspase-3 and Bax in the hippocampus was tested by western blot. Our results show that a chronic administration of ICA (20 mg/kg) can prevent CUMS-induced depressant-like behaviors in male model rats. Additionally, ICA significantly inhibited mitochondrial translocation of GR, reduced mitochondrial outer membrane permeabilization (MOMP) to suppress the release of cytochrome C, and then inhibit the activation of caspase-3. In conclusion, our research provides new evidence to understand the anti-depressant activity of ICA, which relates to its inhibition of neuronal apoptosis in the hippocampus through the mitochondrial apoptotic pathway.

Effect of preserved eggs on the health of SD rats, and anti-tumor action of HT-29 cells.

Preserved eggs are traditional alkali-pickled food in China and have been enjoyed by consumers and extensively studied by researchers for their nutritional tastes and their anti-tumor, anti-inflammatory, antioxidant, lipid-lowering, and blood pressure-lowering properties. To study the anti-tumor effects of preserved eggs, this project observed the health on rats, and anti-tumor effects and separated anti-tumor active components on HT-29 cells. SD rats fed for 80 days showed that preserved eggs had no significant effect on weight, food intake, blood pH, liver tissues, or organ indices. Preserved eggs significantly increased blood levels of oxidative stress markers SOD and CAT, decreased MDA levels by 0.46, 0.23, and 0.25 times. Moreover, they also increased the level of IL-2 from 1233 to 1340 pg/mL. Two water-soluble bioactive peptide fractions, B1 and B2, with molecular weights ≥10 kDa were further obtained from preserved eggs by ultrafiltration and Superdex Peptide 10/300 GL. The potential mechanism of B1 and B2 is to activate the internal mitochondrial apoptotic pathway and induce apoptosis by up-regulating the expression of the pro-apoptotic factors cytochrome C, caspase-3, and caspase-9 mRNA in HT-29 cells.

Piceatannol improved cerebral blood flow and attenuated JNK3 and mitochondrial apoptotic pathway in a global ischemic model to produce neuroprotection.

Cerebral ischemia is one of the leading causes of death and disability worldwide. The only FDA-approved treatment is recanalization with systemic tissue plasminogen activators like alteplase, although reperfusion caused by recanalization can result in neuroinflammation, which can cause brain cell apoptosis. Therefore, after an ischemic/reperfusion injury, interventions are needed to minimize the neuroinflammatory cascade. In the present study, piceatannol (PCT) was studied for its neuroprotective efficacy in a rat model of global ischemic injury by attenuating c-Jun N-terminal kinase 3 (JNK3) downstream signaling. PCT is a resveratrol analog and a polyphenolic stilbenoid naturally occurring in passion fruit and grapes. The neuroprotective efficacy of PCT (1, 5, 10 mg/kg) in ischemic conditions was assessed through pre- and post-treatment. Cerebral blood flow (CBF) and tests for functional recovery were assessed. Protein and gene expression were done for JNK3 and other inflammatory markers. A docking study was performed to identify the amino acid interaction. The results showed that PCT improved motor and memory function as measured by a functional recovery test believed to be due to an increase in cerebral blood flow. Also, the caspase signaling which promotes apoptosis was found to be down-regulated; however, nitric oxide synthase expression was up-regulated, which could explain the enhanced cerebral blood flow (CBF). According to our findings, PCT impeded c-Jun N-terminal kinase 3 (JNK3) signaling by suppressing phosphorylation and disrupting the mitochondrial apoptotic pathway, which resulted in the neuroprotective effect. Molecular docking analysis was performed to investigate the atomic-level interaction of JNK3 and PCT, which reveals that Met149, Leu206, and Lys93 amino acid residues are critical for the interaction of PCT and JNK3. According to our current research, JNK3 downstream signaling and the mitochondrial apoptosis pathway are both inhibited by PCT, which results in neuroprotection under conditions of global brain ischemia. Piceatannol attenuated JNK3 phosphorylation during the ischemic condition and prevented neuronal apoptosis.

A multibiomarker approach to assess the ecotoxicological effects of diclofenac on Asian clam Corbicula fluminea (O. F. Müller, 1774).

Diclofenac (DCF), one of the most current and widely used nonsteroidal anti-inflammatory drugs (NSAIDs), has been frequently detected in aquatic environments worldwide. However, the ecotoxicological effects of DCF on freshwater invertebrates remain largely unknown. In the present study, Corbicula fluminea were exposed to environmentally relevant concentrations of DCF (0, 2, 20, and 200 μg/L) for 28 days, and the potential adverse effects of DCF on siphoning behavior, antioxidant responses, and apoptosis were investigated. Our results showed that the siphon efficiencies of clams were significantly suppressed under DCF stress. DCF exerted neurotoxicity via reducing the activity of acetylcholinesterase (AChE) in gills and digestive gland of C. fluminea. Exposure to DCF induced antioxidant stress and increased malondialdehyde (MDA) levels in both gills and digestive gland of C. fluminea. Transcriptional alterations of apoptosis-related genes indicated that DCF might induce apoptosis by triggering mitochondrial apoptotic pathway. These findings can improve our understanding of the ecological risk of DCF in freshwater ecosystems.

Korean red ginseng suppresses mitochondrial apoptotic pathway in denervation-induced skeletal muscle atrophy

BackgroundSkeletal muscle denervation leads to motor neuron degeneration, which in turn reduces muscle fiber volumes. Recent studies have revealed that apoptosis plays a role in regulating denervation-associated pathologic muscle wasting. Korean red ginseng (KRG) has various biological activities and is currently widely consumed as a medicinal product worldwide. Among them, ginseng has protective effects against muscle atrophy in in vivo and in vitro. However, the effects of KRG on denervation-induced muscle damage have not been fully elucidated. MethodsWe induced skeletal muscle atrophy in mice by dissecting the sciatic nerves, administered KRG, and then analyzed the muscles. KRG was administered to the mice once daily for 3 weeks at 100 and 400 mg/kg/day doses after operation. ResultsKRG treatment significantly increased skeletal muscle weight and tibialis anterior (TA) muscle fiber volume in injured areas and reduced histological alterations in TA muscle. In addition, KRG treatment reduced denervation-induced apoptotic changes in TA muscle. KRG attenuated p53/Bax/cytochrome c/Caspase 3 signaling induced by nerve injury in a dose-dependent manner. Also, KRG decreases protein kinase B/mammalian target of rapamycin pathway, reducing restorative myogenesis. ConclusionThus, KRG has potential protective role against denervation-induced muscle atrophy. The effect of KRG treatment was accompanied by reduced levels of mitochondria-associated apoptosis.

Ginsenoside-Rg1 combined with a conditioned medium from induced neuron-like hUCMSCs alleviated the apoptosis in a cell model of ALS through regulating the NF-κB/Bcl-2 pathway.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease affecting both upper and lower motor neurons in the brain and spinal cord. One important aspect of ALS pathogenesis is superoxide dismutase 1 (SOD1) mutant-mediated mitochondrial toxicity, leading to apoptosis in neurons. This study aimed to evaluate the neural protective synergistic effects of ginsenosides Rg1 (G-Rg1) and conditioned medium (CM) on a mutational SOD1 cell model, and to explore the underlying mechanisms. We found that the contents of nerve growth factor, glial cell line-derived neurotrophic factor, and brain-derived neurotrophic factor significantly increased in CM after human umbilical cord mesenchymal stem cells (hUCMSCs) were exposed to neuron differentiation reagents for seven days. CM or G-Rg1 decreased the apoptotic rate of SOD1G93A-NSC34 cells to a certain extent, but their combination brought about the least apoptosis, compared with CM or G-Rg1 alone. Further research showed that the anti-apoptotic protein Bcl-2 was upregulated in all the treatment groups. Proteins associated with mitochondrial apoptotic pathways, such as Bax, caspase 9 (Cas-9), and cytochrome c (Cyt c), were downregulated. Furthermore, CM or G-Rg1 also inhibited the activation of the nuclear factor-kappa B (NF-κB) signaling pathway by reducing the phosphorylation of p65 and IκBα. CM/G-Rg1 or their combination also reduced the apoptotic rate induced by betulinic acid (BetA), an agonist of the NF-κB signaling pathway. In summary, the combination of CM and G-Rg1 effectively reduced the apoptosis of SOD1G93A-NSC34 cells through suppressing the NF-κB/Bcl-2 signaling pathway (Fig. 1 is a graphical representation of the abstract).

The Protective Role and Mechanism of Mild Therapeutic Hypothermia Protection on Brain Cells.

Moderate therapeutic hypothermia is protective against several cellular stressors. However, the mechanisms behind this protection are not entirely known. In the current investigation, we investigated that therapeutic hypothermia at 33°C administered following peroxide-induced oxidative stress might protect human oligodendroglioma cells using an in vitro model. Tert-butyl peroxide treatment for one hour significantly increased cell apoptosis and suppressed cell viability. In the range of 50-1000 M tert-butyl peroxide, this cell death was dose-dependent. MTT assay and cell apoptosis assay were applied to analyze cell viability/death at 24 hours after peroxide-induced stress. Therapeutic hypothermia at 33°C delivered for two hours after peroxide exposure significantly increased cell viability and suppressed cell death. Even 15 minutes after peroxide washout when delayed hypothermia was used, this protection was still apparent. Three FDA-approved antioxidants (Tempol, EUK134, and Edaravone at 100 M) were added immediately after tert-butyl peroxide, followed by hypothermia treatment. These three antioxidants greatly increased cell viability and cell apoptosis. RT-qPCR was applied to determine the effects of hypothermia treatment on the expression of caspase-3 and -8 as well as tumor necrosis factor-alpha (TNF-α). Therapeutic hypothermia significantly downregulated these three factors. Overall, these findings confirmed that hypothermia and antioxidants quenching reactive oxygen species may lower mitochondrial oxidative stress and/or apoptotic pathways. Further investigation are needed to investigate the role of hypothermia in other cell models.

Potentiation of Cisplatin Cytotoxicity in Resistant Ovarian Cancer SKOV3/Cisplatin Cells by Quercetin Pre-Treatment.

Previously, we demonstrated that the overexpression of antioxidant enzymes (SOD-1, SOD-2, Gpx-1, CAT, and HO-1), transcription factor NFE2L2, and the signaling pathway (PI3K/Akt/mTOR) contribute to the cisplatin resistance of SKOV-3/CDDP ovarian cells, and treatment with quercetin (QU) alone has been shown to inhibit the expression of these genes. The aim of this study was to expand the previous data by examining the efficiency of reversing cisplatin resistance and investigating the underlying mechanism of pre-treatment with QU followed by cisplatin in the same ovarian cancer cells. The pre-incubation of SKOV-3/CDDP cells with quercetin at an optimum dose prior to treatment with cisplatin exhibited a significant cytotoxic effect. Furthermore, a long incubation with only QU for 48 h caused cell cycle arrest at the G1/S phase, while a QU pre-treatment induced sub-G1 phase cell accumulation (apoptosis) in a time-dependent manner. An in-depth study of the mechanism of the actions revealed that QU pre-treatment acted as a pro-oxidant that induced ROS production by inhibiting the thioredoxin antioxidant system Trx/TrxR. Moreover, QU pre-treatment showed activation of the mitochondrial apoptotic pathway (cleaved caspases 9, 7, and 3 and cleaved PARP) through downregulation of the signaling pathway (mTOR/STAT3) in SKOV-3/CDDP cells. This study provides further new data for the mechanism by which the QU pre-treatment re-sensitizes SKOV-3/CDDP cells to cisplatin.

Biological insights in non-small cell lung cancer.

Lung oncogenesis relies on intracellular cysteine to overcome oxidative stress. Several tumor types, including non-small cell lung cancer (NSCLC), upregulate the system xc- cystine/glutamate antiporter (xCT) through overexpression of the cystine transporter SLC7A11, thus sustaining intracellular cysteine levels to support glutathione synthesis. Nuclear factor erythroid 2-related factor 2 (NRF2) serves as a master regulator of oxidative stress resistance by regulating SLC7A11, whereas Kelch-like ECH-associated protein (KEAP1) acts as a cytoplasmic repressor of the oxidative responsive transcription factor NRF2. Mutations in KEAP1/NRF2 and p53 induce SLC7A11 activation in NSCLC. Extracellular cystine is crucial in supplying the intracellular cysteine levels necessary to combat oxidative stress. Disruptions in cystine availability lead to iron-dependent lipid peroxidation, thus resulting in a type of cell death called ferroptosis. Pharmacologic inhibitors of xCT (either SLC7A11 or GPX4) induce ferroptosis of NSCLC cells and other tumor types. When cystine uptake is impaired, the intracellular cysteine pool can be sustained by the transsulfuration pathway, which is catalyzed by cystathionine-B-synthase (CBS) and cystathionine g-lyase (CSE). The involvement of exogenous cysteine/cystine and the transsulfuration pathway in the cysteine pool and downstream metabolites results in compromised CD8+ T cell function and evasion of immunotherapy, diminishing immune response and potentially reducing the effectiveness of immunotherapeutic interventions. Pyroptosis is a previously unrecognized form of regulated cell death. In NSCLCs driven by EGFR, ALK, or KRAS, selective inhibitors induce pyroptotic cell death as well as apoptosis. After targeted therapy, the mitochondrial intrinsic apoptotic pathway is activated, thus leading to the cleavage and activation of caspase-3. Consequently, gasdermin E is activated, thus leading to permeabilization of the cytoplasmic membrane and cell-lytic pyroptosis (indicated by characteristic cell membrane ballooning). Breakthroughs in KRAS G12C allele-specific inhibitors and potential mechanisms of resistance are also discussed herein.

Iodine-Biofortified Lettuce Can Promote Mitochondrial Dependent Pathway of Apoptosis in Human Gastrointestinal Cancer Cells.

Previously, our research provided evidence that exposure of gastric and colon cancer cells to extracts from iodine-biofortified lettuce leads to a reduction of cell viability and proliferation through cell cycle arrest and upregulation of pro-apoptotic genes. The aim of the present study was to determine the potential cellular mechanisms of induction of cell death in human gastrointestinal cancer cell lines after treatment with iodine-biofortified lettuce. We demonstrated that extracts from lettuce enriched with iodine induce apoptosis in gastric AGS and colon HT-29 cancer cells and the mechanism of programmed cell death may be triggered and executed through different signaling pathways, depending on the type of cells. Western blot analysis revealed that iodine-fortified lettuce leads to cell death through the release of cytochrome c to the cytosolic fraction and activation of the primary drivers of apoptosis: caspase-3, caspase-7, and caspase-9. Furthermore, we have reported that apoptotic effects of lettuce extracts may be mediated by poly (ADP-ribose) polymerase (PARP) and activation of pro-apoptotic Bcl-2 family proteins such as Bad, Bax, and BID. We also observed mitochondrial dysfunction with the dissipation of the mitochondrial membrane potential in cells exposed to lettuce extracts. Taken together, these results indicate that the organic form of iodine such as 5-ISA and 3,5-diISA is an important factor in the activation of intrinsic mitochondrial apoptotic pathway in AGS and HT-29 cancer cells in a p53-independent manner.

Tanshinone IIA inhibits endometrial carcinoma growth through the MAPK/ERK/TRIB3 pathway

Endometrial carcinoma is the most common gynecological tumor in developed countries. Tanshinone IIA is a traditional herbal medicine which is to treat cardiovascular disease and has been shown to have various biological effects, such as anti-inflammatory, antioxidative and antitumor activities. However, there has been no study about the effect of tanshinone IIA on endometrial carcinoma. Thus, the aim of this study was to determine the antitumor activity of tanshinone IIA against endometrial carcinoma and investigate the associated molecular mechanism. We demonstrated that tanshinone IIA induced cell apoptosis and inhibited migration. We further demonstrated that tanshinone IIA activated the intrinsic (mitochondrial) apoptotic pathway. Mechanistically, tanshinone IIA induced apoptosis by upregulating TRIB3 expression and inhibiting the MAPK/ERK signaling pathway. In addition, knockdown of TRIB3 with an shRNA lentivirus accelerated proliferation and attenuated inhibition mediated by tanshinone IIA. Finally, we further demonstrated that tanshinone IIA inhibited tumor growth by inducing TRIB3 expression in vivo. In conclusion, these findings suggest that tanshinone IIA has a significant antitumor effect by inducing apoptosis and may be used as a drug for the treatment of endometrial carcinoma.

Novel flavonoid 1,3,4-oxadiazole derivatives ameliorate MPTP-induced Parkinson's disease via Nrf2/NF-κB signaling pathway

Parkinson's disease (PD) is a progressive neurodegenerative disorder with a complex etiology. Neuroinflammation and oxidative stress are important factors driving the progression of PD. It has been reported that 1,3,4-oxadiazole and flavone derivatives have numerous biological functions, especially in the aspect of anti-inflammatory and antioxidant. Based on the strategy of pharmacodynamic combination, we introduced 1,3,4-oxadiazole moiety into the flavonoid backbone, designed and synthesized a series of novel flavonoid 1,3,4-oxadiazole derivatives. Further, we evaluated their toxicity, anti-inflammatory and antioxidant activities using BV2 microglia. Following a comprehensive analysis, compound F12 showed the best pharmacological activity. In vivo, we induced the classical PD animal model by intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) into C57/BL6J mice. Our results showed that compound F12 ameliorated MPTP-induced dysfunction in mice. Further, compound F12 reduced oxidative stress by promoting the nucleation of nuclear factor erythroid 2-related factor 2 (Nrf2) and decreased the inflammatory response by inhibiting the nuclear translocation of nuclear factor-κB (NF-κB) in vivo and in vitro. Meanwhile, compound F12 inhibited the mitochondrial apoptotic pathway to rescue microglia inflammation-mediated loss of dopaminergic neurons. In conclusion, compound F12 reduced oxidative stress and inflammation and could be as a potential agent for PD treatment.

Exopolysaccharide from Lactiplantibacillus plantarum YT013 and Its Apoptotic Activity on Gastric Cancer AGS Cells

Cancer is a significant health burden in the world. Natural product drugs have received widespread attention because of their safety and effectiveness, stable effects and fewer side effects. Some studies have demonstrated that exopolysaccharide (EPS) from lactic acid bacteria (LAB) can inhibit the growth of many types of cancer cells. In this work, the effects of the EPS from Lactiplantibacillus plantarum YT013 on gastric cancer cells were investigated. Its cytotoxicity was evaluated by MTT assay; at the concentration of 1000 μg/mL, the most significant inhibitory effect occurred in AGS cells, followed by SGC-7901, PANC-1 and HCT116, and less inhibited in HepG2 cells. Cell cycle results showed that EPS prevented AGS cells from transitioning from the S phase to the G2/M phase. In addition, the results of flow cytometry showed that EPS promoted apoptosis in a concentration-dependent manner. Western blotting also indicated that EPS might lead to apoptosis via the endogenous mitochondrial apoptotic pathway. The safety of lyophilized powder, cell-free culture supernatant and EPS from Lactiplantibacillus plantarum YT013 were evaluated by observing tissue organs through H&E staining, and the results showed that the components were safe and effective and could provide a basis for the development of natural anticancer active drugs.

FAR591 promotes the pathogenesis and progression of SONFH by regulating Fos expression to mediate the apoptosis of bone microvascular endothelial cells

The specific pathogenesis of steroid-induced osteonecrosis of the femoral head (SONFH) is still not fully understood, and there is currently no effective early cure. Understanding the role and mechanism of long noncoding RNAs (lncRNAs) in the pathogenesis of SONFH will help reveal the pathogenesis of SONFH and provide new targets for its early prevention and treatment. In this study, we first confirmed that glucocorticoid (GC)-induced apoptosis of bone microvascular endothelial cells (BMECs) is a pre-event in the pathogenesis and progression of SONFH. Then, we identified a new lncRNA in BMECs via lncRNA/mRNA microarray, termed Fos-associated lincRNA ENSRNOT00000088059.1 (FAR591). FAR591 is highly expressed during GC-induced BMEC apoptosis and femoral head necrosis. Knockout of FAR591 effectively blocked the GC-induced apoptosis of BMECs, which then alleviated the damage of GCs to the femoral head microcirculation and inhibited the pathogenesis and progression of SONFH. In contrast, overexpression of FAR591 significantly promoted the GC-induced apoptosis of BMECs, which then aggravated the damage of GCs to the femoral head microcirculation and promoted the pathogenesis and progression of SONFH. Mechanistically, GCs activate the glucocorticoid receptor, which translocates to the nucleus and directly acts on the FAR591 gene promoter to induce FAR591 gene overexpression. Subsequently, FAR591 binds to the Fos gene promoter (–245∼–51) to form a stable RNA:DNA triplet structure and then recruits TATA-box binding protein associated factor 15 and RNA polymerase II to promote Fos expression through transcriptional activation. Fos activates the mitochondrial apoptotic pathway by regulating the expression of Bcl-2 interacting mediator of cell death (Bim) and P53 upregulated modulator of apoptosis (Puma) to mediate GC-induced apoptosis of BMECs, which leads to femoral head microcirculation dysfunction and femoral head necrosis. In conclusion, these results confirm the mechanistic link between lncRNAs and the pathogenesis of SONFH, which helps reveal the pathogenesis of SONFH and provides a new target for the early prevention and treatment of SONFH.

Activation of AMPK signalling by Metformin: Implication an important molecular mechanism for protecting against mice silicosis via inhibited endothelial cell-to-mesenchymal transition by regulating oxidative stress and apoptosis

Inhalation of silica particles (SiO2) causes oxidative stress-induced inflammation and cell apoptosis, ultimately resulting in irreversible pulmonary fibrosis, Unfortunately, effective treatment or preventative measures have yet to be fully established. Metformin (Met), a relatively safe and effective medication for treating diabetes, may hold promise as protective agent against early-stage pulmonary fibrosis in mice through the activation of autophagy and inhibition of endothelial cell to mesenchymal transition (EndoMT). Here, we investigated whether Met could reduce silicosis in mice by regulating inflammation, oxidative stress, and apoptosis, and to identify the underlying protective effect on endothelial cells. First, through pathological observation, we found that 21 consecutive days of Met (100 mg/kg) administration is optimal against silicosis. Next, using haematoxylin–eosin and Masson’s trichrome staining and immunoblotting, we found that Met effectively blunted the inflammatory response and collagen deposition at 56 days after exposure to SiO2. We also demonstrated that Met effectively activates AMPK signalling and markedly relieves oxidative stress, the mitochondrial apoptotic pathway and EndoMT induced by SiO2 exposure both in vivo and in vitro. Overall, Met can alleviate SiO2-induced pulmonary fibrosis by regulating oxidative stress and the mitochondrial apoptotic pathway. The current study provides a rationale for the clinical treatment of SiO2-induced pulmonary fibrosis.