A novel compound derived from danshensu inhibits apoptosis via upregulation of heme oxygenase-1 expression in SH-SY5Y cells

Chrysanthemum boreale Makino Inhibits Oxidative Stress-Induced Neuronal Damage in Human Neuroblastoma SH-SY5Y Cells by Suppressing MAPK-Regulated Apoptosis

Oxidative stress has been demonstrated to play a pivotal role in the pathological processes of many neurodegenerative diseases. In the present study, we demonstrated that Chrysanthemum boreale Makino extract (CBME) suppresses oxidative stress-induced neurotoxicity in human neuroblastoma SH-SY5Y cells and elucidated the underlying molecular mechanism. Our observations revealed that CBME effectively protected neuronal cells against H₂O₂-induced cell death by preventing caspase-3 activation, Bax upregulation, Bcl-2 downregulation, activation of three mitogen-activated protein kinases (MAPKs), cAMP response element-binding protein (CREB) and NF-κB phosphorylation, and iNOS induction. These results provide evidence that CBME has remarkable neuroprotective properties in SH-SY5Y cells against oxidative damage, suggesting that the complementary or even alternative role of CBME in preventing and treating neurodegenerative diseases is worth further studies.

Daphnetin, a Coumarin in Genus Stellera Chamaejasme Linn: Chemistry, Bioactivity and Therapeutic Potential

Coumarins is a huge family of phenolic compounds containing a common structure of 2 H -1-benzopyran-2-one. Nowadays, more than 1,300 natural-based coumarins have been identified in a variety of plants, bacteria and fungi, many of them exhibited promising biomedical performance. Daphnetin (7,8-dihydroxycoumarin) is a typical coumarin associated with a couple of bioactivities such as anti-cancer, antibacterial, anti-inflammatory and anti-arthritis. In the treatment of diseases, it has been verified that daphnetin has outstanding therapeutic effects on diabetes, arthritis, transplant rejection, cancer and even on central nervous system diseases. Herein, we summarized the chemical synthetic methodologies, bioactivities, therapeutic potentials and structure-activity relationships of daphnetin and its derivatives. Hopefully, this review would be beneficial for the discovery of new coumarin-based biomedicine in the near future.

Activation of Atg7-dependent autophagy by a novel inhibitor of the Keap1-Nrf2 protein-protein interaction from Penthorum chinense Pursh. attenuates 6-hydroxydopamine-induced ferroptosis in zebrafish and dopaminergic neurons

The death of dopaminergic neurons is a dominant factor during the occurrence and development of Parkinson's disease (PD). Previous studies demonstrated that ferroptosis is implicated in the death of dopaminergic neurons. Besides, polyphenols have been proven to be effective in preventing the death of dopaminergic neurons. This work aims to explore the neuroprotective effect and mechanism of thonningianin A (Th A), a polyphenolic compound in natural plant foods, against 6-hydroxydopamine (6-OHDA)-induced ferroptosis in dopaminergic cells. The results of molecular docking and other binding assays collectively demonstrated that Th A can strongly target the Kelch domain of Keap1. Th A treatment significantly facilitated the nuclear factor erythroid 2-like 2 (Nrf2) nuclear translocation and subsequently increased the heme oxygenase-1 (HO-1) protein level through inhibiting the protein-protein interaction (PPI) of Keap1 and Nrf2. Compared with the nomifensine (Nomi) treatment, Th A had a more potent protective effect on 6-OHDA-induced ferroptosis during PD pathology in zebrafish, which was associated with assuaging the reduction of the total swimming distance, glutathione (GSH) depletion, iron accumulation, lipid peroxidation, and aggregation of α-synuclein (α-syn). Furthermore, Th A also exhibited a strong protective effect against 6-OHDA-induced ferroptosis in vitro in the human neuroblastoma cell line SH-SY5Y. Th A degraded Keap1 protein through activating Atg7-dependent autophagy. Additionally, Th A treatment facilitated the degradation of Keap1 protein by promoting the interaction between p62/SQSTM1 (sequestosome 1, hereafter referred to as p62) and Keap1. Taken together, our findings indicated that Th A protects dopaminergic cells against 6-OHDA-induced ferroptosis through activating the Nrf2-based cytoprotective system, thus enabling a potential application of Keap1-Nrf2 PPI inhibitors in the restraint of ferroptosis and treatment of PD.

Pyroptosis in acute pancreatitis and its therapeutic regulation

Pyroptosis defines a new type of GSDMs-mediated programmed cell death, distinguishes from the classical concepts of apoptosis and necrosis-mediated cell death and is prescribed by cell swelling and membrane denaturation, leading to the extensive secretion of cellular components and low-grade inflammatory response. However, NLRP3 inflammasome activation can trigger its downstream inflammatory cytokines, leading to the activation of pyroptosis-regulated cell death. Current studies reveal that activation of caspase-4/5/11-driven non-canonical inflammasome signaling pathways facilitates the pathogenesis and progression of acute pancreatitis (AP). In addition, a large number of studies have reported that NLRP3 inflammasome-dependent pyroptosis is a crucial player in driving the course of the pathogenesis of AP. Excessive uncontrolled GSDMD-mediated pyroptosis has been implicated in AP. Therefore, the pyroptosis-related molecule GSDMD may be an independent prognostic biomarker for AP. The present review paper summarizes the molecular mechanisms of pyroptotic signaling pathways and their pathophysiological impacts on the progress of AP. Moreover, we briefly present some experimental compounds targeting pyroptosis-regulated cell death for exploring novel therapeutic directions for the treatment and management of AP. Our review investigations strongly suggest that targeting pyroptosis could be an ideal therapeutic approach in AP.

Hesperidin alleviates bupivacaine anesthesia-induced neurotoxicity in SH-SY5Y cells by regulating apoptosis and oxidative damage

Local anesthetic with bupivacaine (BV) administration may cause severe neurotoxicity and neurological complications in developing neurons. Any substances that can mitigate the toxic effects of BV are of great importance in surgical procedures and pain management. The present study attempted to investigate if hesperidin (HN) could inhibit or prevent BV-induced neurotoxicity in SH-SY5Y cells. Exposure of BV at 5 mM resulted in a significant decrease of cell viability and a remarkable increase of lactate dehydrogenase release via the induction of apoptosis and production of reactive oxygen species. Moreover, a loss of mitochondrial membrane potential, decreased Bcl-2 protein expression, as well as increased expression of cytoplasmic cytochrome c, Bax, and cleaved caspase-3 protein was also observed in BV-stimulated SH-SY5Y cells. In addition, BV stimulation impaired the balance of oxidation-reduction and inflammation system, as evidenced by the increased malondialdehyde content, decreased superoxide dismutase and catalase activity, and reduced level of reduced glutathione, interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α. However, these iatrogenic changes were all reversed by the HN (5, 10, and 20 μM) supplement for 48 h in a concentration-dependent manner. In conclusion, HN can protect SH-SY5Y cells against BV-stimulated neurotoxicity via the inhibition of apoptosis, oxidative stress, and inflammation response. The present findings suggested that HN may be an effective alternative agent to inhibit or prevent BV-induced neurotoxicity in human patients.

A novel danshensu derivative ameliorates experimental colitis by modulating NADPH oxidase 4-dependent NLRP3 inflammasome activation

We have previously reported a novel compound [4‐(2‐acetoxy‐3‐((R)‐3‐(benzylthio)‐1‐methoxy‐1‐oxopropan‐2‐ylamino)‐3‐oxopropyl)‐1,2‐phenylene diacetate (DSC)], derived from danshensu, exhibits cytoprotective activities in vitro. Here, we investigated the effects and underlying mechanisms of DSC on dextran sodium sulphate (DSS)‐induced experimental colitis. We found that DSC treatment afforded significant protection against the development of colitis, evidencing by suppressed inflammatory responses and enhanced barrier integrity. Intriguingly, DSC specifically down‐regulated DSS‐induced colonic NADPH oxidase 4 (Nox4) expression, accompanied by a balanced redox status, suppressed nuclear factor‐κB (NF‐κB) and NLRP3 inflammasome activation and up‐regulated nuclear factor (erythroid‐derived 2)‐like 2 and haeme oxygenase‐1 expression. In vitro study also demonstrated DSC also markedly decreased Nox4 expression and activity associated with inhibiting reactive oxygen species generation, NF‐κB activation and NLRP3 inflammasome activation in bone marrow‐derived macrophages. Either lentiviral Nox4 shRNA‐mediated Nox4 knockdown or Nox4‐specific small‐interfering RNA mimicked effects of DSC by suppressing NLPR3 inflammasome activation to alleviate experimental colitis or inflammatory macrophage response. Collectively, our results provide the first evidence that DSC ameliorates experimental colitis partly through modulating Nox4‐mediated NLRP3 inflammasome activation.

Activation of p62-Keap1-Nrf2 Pathway Protects 6-Hydroxydopamine-Induced Ferroptosis in Dopaminergic Cells

Parkinson's disease (PD) is a common neurodegenerative disorder primarily caused by the death of dopaminergic neurons in the substantia nigra pars compacta (SNpc). However, the manner of death of dopaminergic neurons remains indistinct. Ferroptosis is a form of cell death involving in the iron-dependent accumulation of glutathione depletion and lipid peroxide. Besides, previous studies indicated that ferroptosis might be involved in the death of dopaminergic neurons. In this study, we aim to explore the protective effect of the p62-Keap1-Nrf2 pathway against 6-hydroxydopamine (6-OHDA)-induced ferroptosis in dopaminergic cells. Firstly, our results demonstrated that 6-OHDA-induced ferroptosis could be observed in vivo zebrafish and in vitro human dopaminergic cell line (SH-SY5Y cells) model. Moreover, ferroptosis induced by 6-OHDA mitigates in SH-SY5Y cells upon ferrostatin-1 (Fer, an inhibitor of ferroptosis) treatment via upregulating the protein expression of glutathione peroxidase 4 (GPX4). Then, we found that high p62/SQSTM1 (p62) expression could protect SH-SY5Y cells against ferroptosis through promoting Nrf2 nuclear transfer and upregulating the expression of the antioxidant protein heme oxygenase-1 (HO-1). Ultimately, high p62 expression activates the Nrf2/HO-1 signaling pathway through binding to Kelch-like ECH-associated protein 1 (Keap1). Collectively, the activation of the p62-Keap1-Nrf2 pathway prevents 6-OHDA-induced ferroptosis in SH-SY5Y cells, targeting this pathway in combination with a pharmacological inhibitor of ferroptosis can be a potential approach for PD therapy.

Therapeutic potential of natural compounds from Chinese medicine in acute and subacute phases of ischemic stroke

Stroke is one of the leading causes of death and disability in adults worldwide, resulting in huge social and financial burdens. Extracts from herbs, especially those used in Chinese medicine, have emerged as new pharmaceuticals for stroke treatment. Here we review the evidence from preclinical studies investigating neuroprotective properties of Chinese medicinal compounds through their application in acute and subacute phases of ischemic stroke, and highlight potential mechanisms underlying their therapeutic effects. It is noteworthy that many herbal compounds have been shown to target multiple mechanisms and in combinations may exert synergistic effects on signaling pathways, thereby attenuating multiple aspects of ischemic pathology. We conclude the paper with a general discussion of the prospects for novel natural compound-based regimens against stroke.

Therapeutic effect and mechanism study of L-cysteine derivative 5P39 on LPS-induced acute lung injury in mice

Organosulfur compounds, such as L-cysteine, allicin and other sulfur-containing organic compounds in Allium species, have been proposed to possess many important physiological and pharmacological functions. A novel L-cysteine derivative, t-Butyl S-allylthio-L-cysteinate (5P39), was designed and synthesized by combining L-cysteine derivative and allicin pharmacophore through a disulfide bond. This study aimed to explore the effects and mechanisms of 5P39 on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. At the experimental concentration (5, 10 and 20 μM), 5P39 suppressed the excessive secretion of nitric oxide (NO) and interleukin-6 (IL-6) in mice peritoneal macrophages stimulated by LPS. A mouse model of ALI was established by tracheal instillation of LPS for 2 h before 5P39 (30 and 60 mg/kg) administration. The results showed that 5P39 treatment down-regulated the wet/dry weight ratio (W/D ratio) of lungs and reduced the protein concentration, the number of total cells as well as the myeloperoxidase (MPO) activity in bronchoalveolar lavage fluid (BALF). 5P39 administration improved the histopathological changes of lungs in ALI mice with the decreased levels of pro-inflammatory cytokines in BALF. The inhibitory effects of 5P39 on the toll-like receptor 4 (TLR4) expression and macrophages accumulation in lung tissues were observed by immunohistochemistry. Additionally, 5P39 significantly attenuated the LPS-activated high expression of key proteins in TLR4/MyD88 signaling pathway. Taken together, the present study showed that 5P39 effectively alleviate the severity of ALI, and its mechanism might relate to the inhibition of LPS-activated TLR4/MyD88 signaling pathway, demonstrating a promising potential for further development into an anti-inflammatory drug candidate.

A Novel Derivative of the Natural Product Danshensu Suppresses Inflammatory Responses to Alleviate Caerulein-Induced Acute Pancreatitis

Acute pancreatitis (AP), a common abdominal inflammatory disorder, is characterized by premature intracellular activation of digestive proteases within pancreatic acini and a consecutive systemic inflammatory response. Although the mechanism remains to be fully understood, inflammation is the main cause of pancreatic damage in AP. A novel compound [4-(2-acetoxy-3-((R)-3-(benzylthio)-1-methoxy-1-oxopropan-2-ylamino)-3-oxopropyl)-1,2-phenylene diacetate (DSC)], derived from danshensu, exhibits anti-inflammatory and anti-apoptotic properties in vitro. However, its potential beneficial effect in AP has not been demonstrated. This study aimed to investigate the effects and underlying mechanisms of DSC in experimental AP in mice. We found that DSC suppressed inflammatory responses in AP by inhibiting the activation of nuclear factor-κB (NF-κB), signal transducer and activator of transcription 3 (STAT3) and nucleotide-binding domain leucine-rich repeat containing family, pyrin domain-containing 3 (NLRP3) inflammasome. Furthermore, treatment with DSC modulated the infiltration of neutrophils and the phenotypes of macrophages in mice induced with AP. Interestingly, we found that the expression of nuclear factor-erythroid 2 related factor 2 (Nrf2) and its regulated antioxidant enzyme heme oxygenase-1 (HO-1), which modulate inflammatory activities, was significantly increased in DSC-treated groups. Together, our findings demonstrate that DSC alleviates pancreatic inflammation and damage in AP by inhibiting the activation of NF-κB, STAT3, and NLRP3 inflammasome and modulating immune cell responses.

The inhibition of heme oxigenase-1 (HO-1) abolishes the mitochondrial protection induced by sesamol in LPS-treated RAW 264.7 cells

Redox impairment and mitochondrial dysfunction have been seen in inflammation. Thus, there is interest in studies aiming to find molecules that would exert mitochondrial protection in mammalian tissues undergoing inflammation. Sesamol (SES) is an antioxidant and anti-inflammatory molecule as demonstrated in both in vitro and in vivo experimental models. Nonetheless, it was not previously demonstrated whether and how SES would cause mitochondrial protection during inflammation. Thus, we investigated here whether a pretreatment (for 1 h) with SES (1-100 μM) would prevent mitochondrial impairment in lipopolysaccharide (LPS)-treated RAW 264.7 cells. It was also evaluated whether the heme oxigenase-1 (HO-1) would be involved in the effects on mitochondria induced by SES. We found that SES reduced the levels of lipid peroxidation and protein nitration in the membranes of mitochondria obtained from LPS-treated RAW 264.7 cells. SES also attenuated the production of superoxide anion radical (O₂^-•) and nitric oxide (NO^•) in this experimental model. SES suppressed the LPS-elicited mitochondrial dysfunction, as assessed through the analyses of the activities of the mitochondrial complexes I and V. SES also abrogated the LPS-induced decrease in the levels of adenosine triphosphate (ATP) and in the mitochondrial membrane potential (MMP). SES induced mitochondria-related anti-apoptotic effects in LPS-treated cells. Besides, SES pretreatment abrogated the LPS-triggered inflammation by decreasing the levels of pro-inflammatory proteins. The SES-induced mitochondria-associated protection was blocked by the specific inhibitor of HO-1, ZnPP IX (20 μM). Therefore, SES induced mitochondrial protection in LPS-treated cells by a mechanism involving HO-1.

Noninvasive Real-Time Characterization of Renal Clearance Kinetics in Diabetic Mice after Receiving Danshensu Treatment

Danshensu (DSS) is an active ingredient extracted from the root of the Danshen that could ameliorate oxidative stress via upregulation of heme oxygenase- (HO-) 1. Little is known about the treatment effects of DSS on kidney function in diabetic mice. Therefore, the primary aim of the present study was to characterize the renal clearance kinetics of IRdye800CW in db/db mice after DSS treatment. The secondary aim was to measure several biomarkers of renal function and oxidative stress (urinary F2-isoprostane, HO-1 in kidney and serum bilirubin). Fourteen db/db diabetic mice were randomly assigned into two groups and received either DSS treatment (DM + DSS) or vehicle treatment (DM). A third group that comprised of db/+ nondiabetic mice (non-DM control) received no DSS treatment and served as the nondiabetic control. At the end of a 3-week intervention period, serum and urinary biomarkers of renal function and oxidative stress were assessed and the renal clearance of IRdye800CW dye in all mice was determined noninvasively using Multispectral Optoacoustic Tomography. The major finding from this study suggested that DSS treatment in db/db mice improved renal clearance. Increased expression of HO-1 after DSS treatment also suggested that DSS might represent a potential therapeutic avenue for clinical intervention in diabetic nephropathy.

Melandrii Herba Extract Attenuates H₂O₂-Induced Neurotoxicity in Human Neuroblastoma SH-SY5Y Cells and Scopolamine-Induced Memory Impairment in Mice

Oxidative stress plays a significant role in the etiology of a variety of neurodegenerative diseases. In this study, we found that Melandrii Herba extract (ME) attenuated oxidative-induced damage in cells. Mechanistically, ME exhibited protection from H₂O₂-induced neurotoxicity via caspase-3 inactivation, Bcl-2 downregulation, Bax upregulation, and MAPK activation (ERK 1/2, JNK 1/2, and p38 MAPK) in vitro. Moreover, our in vivo data showed that ME was able to attenuate scopolamine-induced cognitive impairment. These results provide in vitro and in vivo evidence that ME exhibits neuroprotective properties against oxidative stress, which suggests that ME is worthy of further investigation as a complementary, or even as an alternative, product for preventing and treating neurodegenerative disorders.

S-propargyl-cysteine attenuates inflammatory response in rheumatoid arthritis by modulating the Nrf2-ARE signaling pathway

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disorder. Hydrogen sulfide (H₂S), the third physiological gasotransmitter, is well recognized as an anti-inflammatory mediator in various inflammatory conditions. Herein, we explored the protective effects of S-propargyl-cysteine (SPRC, also known as ZYZ-802), an endogenous H₂S modulator, on RA and determined the underlying mechanisms. In the present study, SPRC concentration-dependently attenuated inflammatory mediator expression, reactive oxidase species generation, and the expression and activity of matrix metalloproteinases (MMP)-9 in interleukin (IL)-1β-induced human rheumatoid fibroblast-like synoviocytes MH7A. In addition, SPRC blocked IL-1β-mediated migration and invasion of MH7A cells. As expected, the protective effects of SPRC were partially abrogated by DL-propargylglycine (PAG, a H₂S biosynthesis inhibitor). In vivo study also demonstrated that SPRC treatment markedly ameliorated the severity of RA in adjuvant-induced arthritis rats, and this effect was associated with the inhibition of inflammatory response. We further identified that SPRC remarkably induced heme oxygenase-1 expression associated with the degradation of Kelch-like ECH-associated protein 1 (Keap1) and nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2); this effect was attributed to the sulfhydrylation of the cysteine residue of Keap1. Our data demonstrated for the first time that SPRC, an endogenous H₂S modulator, exerted anti-inflammatory properties in RA by upregulating the Nrf2-antioxidant response element (ARE) signaling pathway.

Daphnetin protects oxidative stress-induced neuronal apoptosis via regulation of MAPK signaling and HSP70 expression

Neurodegenerative disorders are characterized by progressive degeneration and loss of neurons in the brain. Oxidative stress is implicated in the pathogenesis of neurological disorders, although the pathological mechanism remains unelucidated. Daphnetin, an active ingredient extracted from Changbai daphne (Daphne Korean Nakai), exhibits various pharmacological effects, including anti-inflammatory, anti-oxidative and anti-tumor effects. However, the neuroprotective effects, as well as the specific mechanisms of daphnetin, remain unclear. Neuronal-like rat pheochromocytoma PC12 cells were pretreated with daphnetin for 2 h, then treated with or without H₂O₂ for various times. Cell morphology was detected using an inverted microscope, the apoptotic ratio was determined by Annexin V fluorescein isothiocyanate/propidium iodide assay, nuclear morphology was observed and photographed using a fluorescence microscope following 4',6-diamidino-2-phenylindole staining. The levels of pro-caspase 3, cleavage of poly ADP-ribose polymerase and caspase 3 were detected by western blotting. In addition, the activation of mitogen-activated protein kinase (MAPK) signal pathway and the expression of HSP70 were detected by western blotting. The present study demonstrated that daphnetin attenuated hydrogen peroxide (H₂O₂)-induced apoptosis in a concentration-dependent manner, reduced the cleavage of poly ADP ribose polymerase and caspase 3, and inhibited the phosphorylation of p38 MAPK and c-Jun N-terminal kinases (JNK) in H₂O₂-induced PC12 cells. In addition, daphnetin induced the expression of HSP70 in a dose- and time-dependent manner, and daphnetin-induced HSP70 expression was reduced by extracellular signal-regulated kinase (ERK) 1/2 inhibitor U0126 in PC12 cells. Therefore, the present results indicate that daphnetin protects PC12 cells against oxidative stress injury by regulating p38 MAPK and JNK signaling and increasing the expression of HSP70 via ERK signaling. This suggests that daphnetin may have the potential to treat certain neurodegenerative diseases. The present results not only provide insight into the potential use of daphnetin in H₂O₂-induced PC12 cell apoptosis, but also highlight the potential role of HSP70 in neuroprotection.

Boehmenan, a lignan from the Chinese medicinal plant Clematis armandii, induces apoptosis in lung cancer cells through modulation of EGF-dependent pathways

BACKGROUND

Epidermal growth factor receptor (EGFR) is an effective molecular target for cancer treatment. Boehmenan, a lignan from the dried stems of Clematis armandii, exhibited the potent cytotoxic effects against many cancer cell lines in previous studies. However, the effects and underlying mechanism of boehmenan on non-small cell lung cancer (NSCLC) remains unclear.

PURPOSE

The present study was designed to determine the in vitro anti-cancer properties and underlying molecular mechanisms of boehmenan on A549 NSCLC cells.

STUDY DESIGN/METHODS

Cellular viability and chemoattractive properties of macrophages were investigated by using MTT and transwell migration assay, respectively. Mitochondrial membrane potential (ΔΨm), apoptotic ratio, and cell cycle were measured by flow cytometry. Protein expression was visualized by Western blot using specific antibodies.

RESULTS

Boehmenan concentration-dependently suppressed proliferation and induced G1 phase arrest in A549 NSCLC cells, which were accompanied by reduction of migration, colony formation and increase of apoptosis in A549 cells. In addition, boehmenan treatment markedly modulated apoptosis-related protein (p53, p21, cleaved caspase 3, and cleaved PARP) and cyclin D1 expression and induced ΔΨm collapse in a concentration dependent manner. Furthermore, boehmenan concentration-dependently inhibited EGF-induced activation of EGFR and its downstream signaling molecules, including MEK, Akt, ERK1/2, and STAT3.

CONCLUSION

Taken together, our results suggested that boehmenan-mediated anti-tumor property was mediated by modulation of mitochondria and EGFR signaling pathway in A549 NSCLC cells.

Differences in vulnerability of neurons and astrocytes to heme oxygenase-1 modulation: Implications for mitochondrial ferritin

Induction of the antioxidant enzyme heme oxygenase-1 (HO-1) was observed in both astrocytes and neurons in the substantia nigra of patients with Parkinson's disease (PD). In the current study, we investigated whether HO-1 behaves differently between neurons and astrocytes under the condition of neurotoxicity related to PD. The results showed a time-dependent HO-1 upregulation in primary cultured ventral mesencephalon neurons and astrocytes treated with the mitochondria complex I inhibitor 1-methyl-4-phenylpyridinium (MPP(+)) or recombinant α-synuclein. However, HO-1 upregulation appeared much later in neurons than in astrocytes. The HO-1 inhibitor zinc protoporphyrin (ZnPP) aggravated MPP(+)- or α-synuclein-induced oxidative damage in both astrocytes and neurons, indicating that this HO-1 response was cytoprotective. For neurons, the HO-1 activator cobalt protoporphyrin IX (CoPPIX) exerted protective effects against MPP(+) or α-synuclein during moderate HO-1 upregulation, but it aggravated damage at the peak of the HO-1 response. For astrocytes, CoPPIXalways showed protective effects. Higher basal and CoPPIX-induced mitochondrial ferritin (MtFt) levels were detected in astrocytes. Lentivirus-mediated MtFt overexpression rescued the neuronal damage induced by CoPPIX, indicating that large MtFt buffering capacity contributes to pronounced HO-1 tolerance in astrocytes. Such findings suggest that astrocyte-targeted HO-1 interventions and MtFt modulations have potential as novel pharmacological strategies in PD.

Regeneration in the nervous system with erythropoietin

Globally, greater than 30 million individuals are afflicted with disorders of the nervous system accompanied by tens of thousands of new cases annually with limited, if any, treatment options. Erythropoietin (EPO) offers an exciting and novel therapeutic strategy to address both acute and chronic neurodegenerative disorders. EPO governs a number of critical protective and regenerative mechanisms that can impact apoptotic and autophagic programmed cell death pathways through protein kinase B (Akt), sirtuins, mammalian forkhead transcription factors, and wingless signaling. Translation of the cytoprotective pathways of EPO into clinically effective treatments for some neurodegenerative disorders has been promising, but additional work is necessary. In particular, development of new treatments with erythropoiesis-stimulating agents such as EPO brings several important challenges that involve detrimental vascular outcomes and tumorigenesis. Future work that can effectively and safely harness the complexity of the signaling pathways of EPO will be vital for the fruitful treatment of disorders of the nervous system.

Neuroprotective effects of Kukoamine B against hydrogen peroxide-induced apoptosis and potential mechanisms in SH-SY5Y cells

Oxidative stress mediates the cell damage in several neurodegenerative diseases, including multiple sclerosis, Alzheimer's disease (AD) and Parkinson's disease (PD). This study aimed at investigating the protective effects of Kukoamine B (KuB) against hydrogen peroxide (H2O2) induced cell injury and potential mechanisms in SH-SY5Y cells. Our results revealed that treatment with KuB prior to H2O2 exposure effectively increased the cell viability, and restored the mitochondria membrane potential (MMP). Furthermore, KuB enhanced the antioxidant enzyme activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) and decreased the malondialdehyde (MDA) content. Moreover, KuB minimized the ROS formation and inhibited mitochondria-apoptotic pathway, MAPKs (p-p38, p-JNK, p-ERK) pathways, but activated PI3K-AKT pathway. In conclusion, we believed that KuB may potentially serve as an agent for prevention of several human neurodegenerative and other disorders caused by oxidative stress.

FoxO proteins in the nervous system

Acute as well as chronic disorders of the nervous system lead to significant morbidity and mortality for millions of individuals globally. Given the ability to govern stem cell proliferation and differentiated cell survival, mammalian forkhead transcription factors of the forkhead box class O (FoxO) are increasingly being identified as potential targets for disorders of the nervous system, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and auditory neuronal disease. FoxO proteins are present throughout the body, but they are selectively expressed in the nervous system and have diverse biological functions. The forkhead O class transcription factors interface with an array of signal transduction pathways that include protein kinase B (Akt), serum- and glucocorticoid-inducible protein kinase (SgK), IκB kinase (IKK), silent mating type information regulation 2 homolog 1 (S. cerevisiae) (SIRT1), growth factors, and Wnt signaling that can determine the activity and integrity of FoxO proteins. Ultimately, there exists a complex interplay between FoxO proteins and their signal transduction pathways that can significantly impact programmed cell death pathways of apoptosis and autophagy as well as the development of clinical strategies for the treatment of neurodegenerative disorders.

Pterostilbene mediates neuroprotection against oxidative toxicity via oestrogen receptor α signalling pathways

Objectives

Accumulating evidence indicated protective role of phytoestrogens against neuronal damage induced by various insults, such as amyloid beta, oxygen deprivation and mitochondrial toxins. Hydrogen peroxide (H2O2) influences the mitochondrial membrane potential, which eventually results in cell apoptosis. In this study, we investigated the effects and possible mechanisms of a phytoestrogen, pterostilbene (PTER), in cell apoptosis induced by H2O2 in human neuronal SH-SY5Y cells. We also analysed the involvement of oestrogen receptors, oestrogen receptor-α and -β (ER-α and ER-β) in the protective role of PTER.

Methods

The effects of PTER on H2O2-stimulated cell were examined using MTT and FACS analysis. The signal pathways and estrogen receptors involved in PTER's effects were investigated using MTT and Western blot analysis.

Key findings

The results showed that H2O2 treatment significantly reduced cell viability in SY5Y cells, which was protected by PTER treatment. We also found that H2O2 inhibited the PI3K/AKT and MAPK/ERK signalling pathways, whereas PTER treatment restored these signalling pathways. We also found that the PTER effect could be largely blocked by an ER-α antagonist, 3-Bis(4-hydroxyphenyl)-4-methyl-5-[4-(2-piperidinylethoxy)phenol]-1H-pyrazole dihydrochloride (MPP), but not by an ER-β antagonist, 4-[2-Phenyl-5,7-bis(trifluoromethyl)pyrazolo[1,5-a] pyrimidin-3-yl]phenol (PHTPP), suggesting that ER-α is a major player in the neuroprotective activity of PTER.

Conclusion

Our study thus demonstrates that PTER is an effective neuroprotective agent presumably through ER-α-mediated signalling pathways.

Asymmetric synthesis and evaluation of danshensu-cysteine conjugates as novel potential anti-apoptotic drug candidates

We have previously reported that the danshensu-cysteine conjugate N-((R)-3-benzylthio-1-methoxy-1-oxo-2-propanyl)-2-acetoxy-3-(3,4-diacetoxyphenyl) propanamide (DSC) is a potent anti-oxidative and anti-apoptotic agent. Herein, we further design and asymmetrically synthesize two diastereoisomers of DSC and explore their potential bioactivities. Our results show that DSC and its two diastereoisomers exert similar protective effects in hydrogen peroxide (H₂O₂)-induced cellular injury in SH-SY5Y cells, as evidenced by the increase of cell viability, superoxide dismutase (SOD), and reduced glutathione (GSH) activity, and glutathione peroxidase (GPx) expression, and the decrease of cellular morphological changes and nuclear condensation, lactate dehydrogenase (LDH) release, and malondialdehyde (MDA) production. In H₂O₂-stimulated human umbilical vein endothelial cells (HUVEC), DSC concentration-dependently attenuates H₂O₂-induced cell death, LDH release, mitochondrial membrane potential collapse, and modulates the expression of apoptosis-related proteins (Bcl-2, Bax, caspase-3, and caspase-9). Our results provide strong evidence that DSC and its two diastereoisomers have similar anti-oxidative activity and that DSC exerts significant vascular-protective effects, at least in part, through inhibition of apoptosis and modulation of endogenous antioxidant enzymes.

Gastrodin protects against MPP(+)-induced oxidative stress by up regulates heme oxygenase-1 expression through p38 MAPK/Nrf2 pathway in human dopaminergic cells

Although the etiology of PD remains unclear, increasing evidence has shown that oxidative stress plays an important role in its pathogenesis and that of other neurodegenerative disorders. The phenolic glucoside gastrodin, a main constituent of a Chinese herbal medicine Gastrodia elata (GE) Blume, has been known to display antioxidant activity. The present study aimed to investigate the protective effects of gastrodin on 1-methyl-4-phenylpyridinium (MPP(+))-induced oxidative cytotoxicity in human dopaminergic SH-SY5Y cells and the underlying mechanism for this neuroprotection. Results indicate that pre-treatment with gastrodin for 1h significantly reduced the MPP(+)-induced viability loss, apoptotic rate and attenuated MPP(+)-mediated ROS production. In addition, gastrodin inhibited MPP(+)-induced lowered membrane potential, decreased Bcl-2/Bax ratio. Moreover, we have revealed the gastrodin increased Nrf2 nuclear translocation, which is upstream of heme oxygenase-1 (HO-1) expression and for the first time revealed gastrodin could increased antioxidant enzyme HO-1 expression in concentration-dependent and time-dependent manners. HO-1 siRNA transfection was employed, and confirmed gastrodin could active the expression of HO-1. And the increase in HO-1 expression was correlated with the protective effect of gastrodin against MPP(+)-induced injury. Because the inhibitor of HO-1 activity, ZnPP reversed the protective effect of gastrodin against MPP(+)-induced cell death. We also demonstrated that the specific p38 MAPK inhibitor, SB203580, concentration-dependently blocked on gastrodin-induced HO-1 expression, and meanwhile SB203580 reversed the protective effect of gastrodin against MPP(+)-induced cell death. Taken together, these findings suggest that gastrodin can induce HO-1 expression through activation of p38 MAPK/Nrf2 signaling pathway, thereby protecting the SH-SY5Y cells from MPP(+)-induced oxidative cell death. Thus our study indicates that gastrodin has a partial cytoprotective role in dopaminergic cell culture systems and could be of importance for the treatment of PD and other oxidative stress-related diseases.

Acetylshikonin, a Novel AChE Inhibitor, Inhibits Apoptosis via Upregulation of Heme Oxygenase-1 Expression in SH-SY5Y Cells

Acetylcholinesterase inhibitors are prominent alternative in current clinical treatment for AD patients. Therefore, there is a continued need to search for novel AChEIs with good clinical efficacy and less side effects. By using our in-house natural product database and AutoDock Vina as a tool in docking study, we have identified twelve phytochemicals (emodin, aloe-emodin, chrysophanol, and rhein in Rhei Radix Et Rhizoma; xanthotoxin, phellopterin, alloisoimperatorin, and imperatorin in Angelicae dahuricae Radix; shikonin, acetylshikonin, isovalerylshikonin, and β,β-dimethylacrylshikonin in Arnebiae Radix) as candidates of AChEIs that were not previously reported in the literature. In addition to AChEI activity, a series of cell-based experiments were conducted for the investigation of their neuroprotective activities. We found that acetylshikonin and its derivatives prevented apoptotic cell death induced by hydrogen peroxide in human and rat neuronal SH-SY5Y and PC12 cells at 10 μM. We showed that acetylshikonin exhibited the most potent antiapoptosis activity through the inhibition of the generation of reactive oxygen species as well as protection of the loss of mitochondria membrane potential. Furthermore, we identified for the first time that the upregulation of heme oxygenase 1 by acetylshikonin is a key step mediating its antiapoptotic activity from oxidative stress in SH-SY5Y cells.

The activation of HO-1/Nrf-2 contributes to the protective effects of diallyl disulfide (DADS) against ethanol-induced oxidative stress

BACKGROUND

Diallyl disulfide (DADS) is a garlic-derived organosulfur compound. The current study is designed to evaluate the protective effects of DADS against ethanol-induced oxidative stress, and to explore the underlying mechanisms by examining the HO-1/Nrf-2 pathway.

METHODS

We investigated whether or not DADS could activate the HO-1 in normal human liver cell LO2, and then evaluated the protective effects of DADS against ethanol-induced damage in LO2 cells and in acute ethanol-intoxicated mice. The biochemical parameters were measured using commercial kits. HO-1 mRNA level was determined by RT-PCR. Histopathology and immunofluorescence assay were performed with routine methods. Protein levels were measured by western blot.

RESULTS

DADS significantly increased the mRNA and protein levels of HO-1, stimulated the nuclear translocation of Nrf-2 and increased the phosphorylation of MAPK in LO2 cells. The nuclear translocation of Nrf-2 was abrogated by MAPK inhibitors. DADS significantly suppressed ethanol-induced elevation of lactate dehydrogenase (LDH) and aspartate transaminase (AST) activities, decrease of glutathione (GSH) level, increase of malondialdehyde (MDA) levels, and apoptosis of LO2 cells, which were all blocked by ZnPPIX. In mice, DADS effectively suppressed acute ethanol-induced elevation of aminotransferase activities, and improved liver histopathological changes, which might be associated with HO-1 activation.

CONCLUSION

These results demonstrate that DADS could induce the activation of HO-1/Nrf-2 pathway, which may contribute to the protective effects of DADS against ethanol-induced liver injury.

GENERAL SIGNIFICANCE

DADS may be beneficial for the prevention and treatment of ALD due to significant activation of HO-1/Nrf-2 pathway.