Oxidative cross-linking of proteins to DNA following ischemia-reperfusion injury

Shuxuening injection improves myocardial injury after myocardial infarction by regulating macrophage polarization via the TLR4/NF-κB and PI3K/Akt signaling pathways

BACKGROUND

Macrophage activation and polarization play pivotal roles in the inflammatory response and myocardial injury associated with myocardial infarction (MI). Modulating macrophage polarization from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype is a promising therapeutic approach for MI. Shuxuening injection (SXNI) is extensively utilized in clinical settings for MI treatment and has demonstrated therapeutic efficacy. However, the effects of SXNI on macrophage polarization post-MI and its underlying mechanisms remain insufficiently understood.

AIM OF THE STUDY

This study is aimed to evaluate the effects of SXNI on macrophage polarization following MI and to elucidate its potential mechanisms of action.

METHODS

A rat model of MI was established by ligation of the left anterior descending coronary artery. The cardioprotective effects of SXNI were assessed through echocardiography, TTC staining, Masson's trichrome staining, HE staining, TUNEL staining, and western blotting (WB). Macrophage polarization was evaluated using ELISA, immunofluorescence staining, and WB. An in vitro model of oxygen-glucose deprivation (OGD) was utilized to simulate MI in macrophages, and qRT-PCR was employed to examine M1/M2 polarization markers. UPLC-Q-TOF/MS was used to identify active components in SXNI. Network pharmacology analysis and molecular docking were utilized to predict the key targets and pathways, which were subsequently validated through WB and immunohistochemistry.

RESULTS

SXNI improved cardiac function, reduced infarct size, and attenuated myocardial tissue damage and apoptosis in MI rats. Staining analyses indicated a reduction in M1 macrophages (CD86+/CD68+) and an increase in M2 macrophages (CD206+/CD68+) in SXNI-treated animals. In vivo and in vitro experiments demonstrated that SXNI decreased M1 markers and pro-inflammatory cytokines levels while increasing M2 markers and the production of anti-inflammatory and pro-angiogenic cytokines. UPLC-Q-TOF/MS analysis identified 18 active components in SXNI. Network pharmacology analysis and molecular docking implicated the TLR4/NF-κB and PI3K/Akt pathways as central mechanisms, which were further confirmed by WB and immunohistochemistry. SXNI inhibited the expression of TLR4 and phosphorylated NF-κB while enhancing phosphorylated PI3 K and Akt levels.

CONCLUSIONS

SXNI modulates the TLR4/NF-κB and PI3K/Akt signaling pathways to promote the polarization of macrophages from the M1 to the M2 phenotype, thereby alleviating myocardial inflammation and injury. These findings provide a scientific basis for the clinical application of SXNI in MI management, and establish a scientific foundation for exploring novel therapeutic strategies for cardiovascular diseases based on macrophage polarization.

SPRTN metalloprotease participates in repair of ROS-mediated DNA-protein crosslinks

Exposure to reactive oxygen species (ROS) can induce DNA-protein crosslinks (DPCs), unusually bulky DNA lesions that block replication and transcription and play a role in aging, cancer, cardiovascular disease, and neurodegenerative disorders. Repair of DPCs depends on the coordinated efforts of proteases and DNA repair enzymes to cleave the protein component of the lesion to smaller DNA-peptide crosslinks which can be processed by tyrosyl-DNA phosphodiesterases 1 and 2, nucleotide excision and homologous recombination repair pathways. DNA-dependent metalloprotease SPRTN plays a role in DPC repair, and SPRTN-deficient mice exhibit an accelerated aging phenotype and develop liver cancer early in life. We investigated the role of the SPRTN enzyme in the repair of DPCs produced by a free radical mechanism. Sprtn-deficient MEF cells treated with ionizing radiation had higher levels of total DPCs and exhibited greater sensitivity upon exposure to hydrogen peroxide and other crosslinking agents including cisplatin, phosphoramide mustard, and 1,2,3,4-diepoxybutane. Using a sensitive and accurate nanoLC-ESI+-MS/MS assay, we specifically measured the radical-induced crosslinking of thymidine in DNA crosslinking of thymidine in DNA to tyrosine in proteins (dT-Tyr) in the tissues of SPRTN hypomorphic (SprtnH/H) and wild type mice. Genomic DNA isolated from the tissues of SPRTN hypomorphic (SprtnH/H) mice exhibited higher levels of dT-Tyr in the liver, brain, heart, and kidney than wild-type animals. Overall, our results are consistent with the understanding that SPRTN has a role in maintaining genomic integrity upon exposure to ionizing radiation and endogenous reactive oxygen species.

Chaperones vs. oxidative stress in the pathobiology of ischemic stroke

As many proteins prioritize functionality over constancy of structure, a proteome is the shortest stave in the Liebig's barrel of cell sustainability. In this regard, both prokaryotes and eukaryotes possess abundant machinery supporting the quality of the proteome in healthy and stressful conditions. This machinery, namely chaperones, assists in folding, refolding, and the utilization of client proteins. The functions of chaperones are especially important for brain cells, which are highly sophisticated in terms of structural and functional organization. Molecular chaperones are known to exert beneficial effects in many brain diseases including one of the most threatening and widespread brain pathologies, ischemic stroke. However, whether and how they exert the antioxidant defense in stroke remains unclear. Herein, we discuss the chaperones shown to fight oxidative stress and the mechanisms of their antioxidant action. In ischemic stroke, during intense production of free radicals, molecular chaperones preserve the proteome by interacting with oxidized proteins, regulating imbalanced mitochondrial function, and directly fighting oxidative stress. For instance, cells recruit Hsp60 and Hsp70 to provide proper folding of newly synthesized proteins-these factors are required for early ischemic response and to refold damaged polypeptides. Additionally, Hsp70 upregulates some dedicated antioxidant pathways such as FOXO3 signaling. Small HSPs decrease oxidative stress via attenuation of mitochondrial function through their involvement in the regulation of Nrf- (Hsp22), Akt and Hippo (Hsp27) signaling pathways as well as mitophagy (Hsp27, Hsp22). A similar function has also been proposed for the Sigma-1 receptor, contributing to the regulation of mitochondrial function. Some chaperones can prevent excessive formation of reactive oxygen species whereas Hsp90 is suggested to be responsible for pro-oxidant effects in ischemic stroke. Finally, heat-resistant obscure proteins (Hero) are able to shield client proteins, thus preventing their possible over oxidation.

Engineered Biomimetic Nanoparticles-Mediated Targeting Delivery of Allicin Against Myocardial Ischemia-Reperfusion Injury by Inhibiting Ferroptosis

Background

Cardiac microvascular damage is substantially related with the onset of myocardial ischaemia-reperfusion (IR) injury. Reportedly, allicin (AL) effectively protects the cardiac microvascular system from IR injury. However, the unsatisfactory therapeutic efficacy of current drugs and insufficient drug delivery to the damaged heart are major concerns. Here, inspired by the natural interaction between neutrophils and inflamed cardiac microvascular endothelial cells (CMECs), a neutrophil membrane-camouflaged nanoparticle for non-invasive active-targeting therapy for IR injury by improving drug delivery to the injured heart is constructed.

Methods

In this study, we engineered mesoporous silica nanoparticles (MSNs) coated with a neutrophil membrane to act as a drug delivery system, encapsulating AL. The potential of the nanoparticles (named AL@MSNs@NM) for specific targeting of infarcted myocardium was assessed using small animal vivo imaging system. The cardiac function of AL@MSNs@NM after treatment was evaluated by Animal Ultrasound Imaging system, HE staining, and Laser Speckle Imaging System. The therapeutic mechanism was analyzed by ELISA kits, immunofluorescence, and PCR.

Results

We discovered that AL@MSNs@NM significantly improves cardiac function index, reduced infarct size and fibrosis, increased vascular perfusion in ischemic areas, and also promoted the function of CMECs, including migration, tube formation, shear stress adaptation, and nitric oxide production. Further research revealed that AL@MSNs@NM have cardio-protective functions in IR rats by inhibiting CMEC ferroptosis and increasing platelet endothelial cell adhesion molecule-1 (PECAM-1) expression.

Conclusion

Our results indicated that AL@MSNs@NM significantly reversed CMEC ferroptosis and increased PECAM-1 expression, enhanced cardiac function, and reduced myocardial infarction size. Therefore, this strategy demonstrates that engineered biomimetic nanotechnology effectively delivers AL for targeted therapy of myocardial infarction.

Methodologies for the detection and sequencing of the epigenetic-like oxidative DNA modification, 8-oxo-7,8-dihydroguanine

The human genome is constantly threatened by endogenous and environmental DNA damaging agents that can induce a variety of chemically modified DNA lesions including 8-oxo-7,8-dihydroguanine (OG). Increasing evidence has indicated that OG is not only a biomarker for oxidative DNA damage but also a novel epigenetic-like modification involved in regulation of gene expression in mammalian cells. Here we summarize the recent progress in OG research focusing on the following points: (i) the mechanism of OG production in organisms and its biological consequences in cells, (ii) the accurate identification of OG in low-abundance genomes and complex biological backgrounds, (iii) the development of OG sequencing methods. These studies will be helpful for further understanding of the molecular mechanisms of OG-induced mutagenesis and its potential roles in human development and diseases such as cancer.

Endogenous Cellular Metabolite Methylglyoxal Induces DNA-Protein Cross-Links in Living Cells

Methylglyoxal (MGO) is an electrophilic α-oxoaldehyde generated endogenously through metabolism of carbohydrates and exogenously due to autoxidation of sugars, degradation of lipids, and fermentation during food and drink processing. MGO can react with nucleophilic sites within proteins and DNA to form covalent adducts. MGO-induced advanced glycation end-products such as protein and DNA adducts are thought to be involved in oxidative stress, inflammation, diabetes, cancer, renal failure, and neurodegenerative diseases. Additionally, MGO has been hypothesized to form toxic DNA-protein cross-links (DPC), but the identities of proteins participating in such cross-linking in cells have not been determined. In the present work, we quantified DPC formation in human cells exposed to MGO and identified proteins trapped on DNA upon MGO exposure using mass spectrometry-based proteomics. A total of 265 proteins were found to participate in MGO-derived DPC formation including gene products engaged in telomere organization, nucleosome assembly, and gene expression. In vitro experiments confirmed DPC formation between DNA and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), as well as histone proteins H3.1 and H4. Collectively, our study provides the first evidence for MGO-mediated DNA-protein cross-linking in living cells, prompting future studies regarding the relevance of these toxic lesions in cancer, diabetes, and other diseases linked to elevated MGO levels.

Sodium Danshensu Cream Promotes the Healing of Pressure Ulcers in Mice through the Nrf2/HO-1 and NF-κB Pathways

On the basis of the mice pressure ulcers (PU) model, the protective effect and potential mechanism of sodium Danshensu (SDSS) cream against PU were investigated. The mice were randomly divided into three groups: the negative control group (cream without 0.5 g SDSS), the SDSS group (cream containing 0.5 g SDSS), and the positive group (0.5 g Hirudoid®). After 7 and 14 days of ointment application, the wound-healing rate of the SDSS and positive groups was significantly higher than that of the control group (p < 0.05). The results of hematoxylin−eosin staining also indicated that SDSS has the potential to promote the healing of PU. In addition, the serum IL-6, IL-1β, TNF-α, and MDA levels decreased significantly (p < 0.01) after 14 days of SDSS treatment, while the SOD, CAT, and GSH-Px activities increased significantly (p < 0.01). In addition, SDSS cream was able to significantly increase the expression of Nrf2, HO-1, GCLM, NQO1, NF-κB p65, NF-κB p50, IKKα, and IKKβ while decreasing the expression of Keap1 and IκBαin the Nrf2/HO-1 and NF-κB pathways. Our research will provide a foundation for the future clinical prevention and treatment of PU with SDSS cream.

Changes in metabolic profiling of whiteleg shrimp (Penaeus vannamei) under hypoxic stress

Hypoxia is a common concern in shrimp aquaculture, affecting growth and survival. Although recent studies have revealed important insights into hypoxia in shrimp and crustaceans, knowledge gaps remain regarding this stressor at the molecular level. In the present study, a gas chromatography-mass spectrometry (GC-MS)-based metabolomics approach was employed to characterize the metabolic signatures and pathways underlying responses of Pacific white shrimp (Penaeus vannamei) to hypoxia and to identify associated candidate biomarkers. We compared metabolite profiles of shrimp haemolymph before (0 h) and after exposure to hypoxia (1 & 2 h). Dissolved oxygen levels were maintained above 85 % saturation in the control and before hypoxia, and 15 % saturation in the hypoxic stress treatment. Results showed 44 metabolites in shrimp haemolymph that were significantly different between before and after hypoxia exposure. These metabolites were energy-related metabolites (e.g., intermediates of citric acid cycle, lactic acid, alanine), fatty acids and amino acids. Pathway analysis revealed 17 pathways that were significantly affected by hypoxia. The changes in metabolites and pathways indicate a shift from aerobic to anaerobic metabolism, disturbance in amino acid metabolism, osmoregulation, oxidative damage and Warburg effect-like response caused by hypoxic stress. Among the altered metabolites, lactic acid was most different between before and after hypoxia exposure and had the highest accurate value for biomarker identification. Future investigations may validate this molecule as a stress biomarker in aquaculture. This study contributes to a better understanding of hypoxia in shrimp and crustaceans at the metabolic level and provides a base for future metabolomics investigations on hypoxia.

Nucleophilic Thiol Proteins Bind Covalently to Abasic Sites in DNA

In the course of studies on the enhancement of 1,2-dibromoethane-induced DNA base pair mutations by O⁶-alkylguanine-DNA alkyltransferase (AGT, MGMT), we discovered the facile reaction of AGT with an abasic site in DNA, leading to covalent cross-linking. The binding of AGT differs from the mechanism reported for the protein HMCES; instead it appears to involve formation of a stable thioglycoside. Facile cross-linking was also observed with the protease papain, which like AGT has a low pK_a cysteine, and the tripeptide glutathione.

Unresolved stalled ribosome complexes restrict cell-cycle progression after genotoxic stress

During the translation surveillance mechanism known as ribosome-associated quality control, the ASC-1 complex (ASCC) disassembles ribosomes stalled on the mRNA. Here, we show that there are two distinct classes of stalled ribosome. Ribosomes stalled by translation elongation inhibitors or methylated mRNA are short lived in human cells because they are split by the ASCC. In contrast, although ultraviolet light and 4-nitroquinoline 1-oxide induce ribosome stalling by damaging mRNA, and the ASCC is recruited to these stalled ribosomes, we found that they are refractory to the ASCC. Consequently, unresolved UV- and 4NQO-stalled ribosomes persist in human cells. We show that ribosome stalling activates cell-cycle arrest, partly through ZAK-p38MAPK signaling, and that this cell-cycle delay is prolonged when the ASCC cannot resolve stalled ribosomes. Thus, we propose that the sensitivity of stalled ribosomes to the ASCC influences the kinetics of stall resolution, which in turn controls the adaptive stress response.

Enzymatic bypass of an N6-deoxyadenosine DNA-ethylene dibromide-peptide cross-link by translesion DNA polymerases

Unrepaired DNA-protein cross-links, due to their bulky nature, can stall replication forks and result in genome instability. Large DNA-protein cross-links can be cleaved into DNA-peptide cross-links, but the extent to which these smaller fragments disrupt normal replication is not clear. Ethylene dibromide (1,2-dibromoethane) is a known carcinogen that can cross-link the repair protein O6-alkylguanine-DNA alkyltransferase (AGT) to the N6 position of deoxyadenosine (dA) in DNA, as well as four other positions in DNA. We investigated the effect of a 15-mer peptide from the active site of AGT, cross-linked to the N6 position of dA, on DNA replication by human translesion synthesis DNA polymerases (Pols) η, ⍳, and κ. The peptide-DNA cross-link was bypassed by the three polymerases at different rates. In steady-state kinetics, the specificity constant (kcat/Km) for incorporation of the correct nucleotide opposite to the adduct decreased by 220-fold with Pol κ, tenfold with pol η, and not at all with Pol ⍳. Pol η incorporated all four nucleotides across from the lesion, with the preference dT > dC > dA > dG, while Pol ⍳ and κ only incorporated the correct nucleotide. However, LC-MS/MS analysis of the primer-template extension product revealed error-free bypass of the cross-linked 15-mer peptide by Pol η. We conclude that a bulky 15-mer peptide cross-linked to the N6 position of dA can retard polymerization and cause miscoding but that overall fidelity is not compromised because only correct pairs are extended.

N-acetylcysteine alleviates post-resuscitation myocardial dysfunction and improves survival outcomes via partly inhibiting NLRP3 inflammasome induced-pyroptosis

Background

NOD-like receptor 3 (NLRP3) inflammasome is necessary to initiate acute sterile inflammation. Increasing evidence indicates the activation of NLRP3 inflammasome induced pyroptosis is closely related to reactive oxygen species (ROS) in the sterile inflammatory response triggered by ischemia/reperfusion (I/R) injury. N-acetylcysteine (NAC) is an antioxidant and plays a protective role in local myocardial I/R injury, while its effect on post-resuscitation myocardial dysfunction, as well as its mechanisms, remain elusive. In this study, we aimed to investigate the effect of NAC on post-resuscitation myocardial dysfunction in a cardiac arrest rat model, and whether its underlying mechanism may be linked to ROS and NLRP3 inflammasome-induced pyroptosis.

Methods

The rats were randomized into three groups: (1) sham group, (2) cardiopulmonary resuscitation (CPR) group, and (3) CPR + NAC group. CPR group and CPR + NAC group went through the induction of ventricular fibrillation (VF) and resuscitation. After return of spontaneous circulation (ROSC), rats in the CPR and CPR + NAC groups were again randomly divided into two subgroups, ROSC 6 h and ROSC 72 h, for further analysis. Hemodynamic measurements and myocardial function were measured by echocardiography, and western blot was used to detect the expression of proteins.

Results

Results showed that after treatment with NAC, there was significantly better myocardial function and survival duration; protein expression levels of NLRP3, adaptor apoptosis-associated speck-like protein (ASC), Cleaved-Caspase-1 and gasdermin D (GSDMD) in myocardial tissues were significantly decreased; and inflammatory cytokines levels were reduced. The marker of oxidative stress malondialdehyde (MDA) decreased and superoxide dismutase (SOD) increased with NAC treatment.

Conclusions

NAC improved myocardial dysfunction and prolonged animal survival duration in a rat model of cardiac arrest. Moreover, possibly by partly inhibiting ROS-mediated NLRP3 inflammasome-induced pryoptosis.

SH2B1 protects cardiomyocytes from ischemia/reperfusion injury via the activation of the PI3K/AKT pathway

BACKGROUND

Apoptosis, reactive oxidative stress (ROS) and inflammation act as the pivotal pathogenesis of myocardial ischemia/reperfusion (I/R) injury (MIRI). Our prior study and other investigation have demonstrated the participations of src homology 2 (SH2) B adaptor protein 1 (SH2B1) in ischemic injury and cardiac hypertrophy; whereas, the involvements of SH2B1 in MIRI and underlying mechanisms are completely unknown.

METHOD

In present study, MIRI model in vivo was induced by 30 min of ligation of LAD coronary artery and 24 h of reperfusion, and primary cultured cardiomyocytes were challenged with 2 h of hypoxia followed by 4 h of reoxygenation (H/R) to mimic MIRI in vitro. Adenovirus encoding for SH2B1 or GFP were pre-transfected into myocardium prior to MIRI both in vivo and in vitro. The myocardial damage, cardiac function, apoptosis, ROS and inflammation were evaluated systematically. Immunofluorescence staining and western blotting were alternatively performed to detect protein expression.

RESULTS

The results exhibited that H/R or I/R significantly reduced SH2B1 in cardiomyocytes, followed by impaired cell survival and function, which were strongly reversed after the adenovirus-mediated SH2B1 up-regulation. Meanwhile, I/R- and H/R-elevated inflammation, apoptosis and ROS were also alleviated by SH2B1 up-regulation. A mechanistic study suggested that the protective contributions of SH2B1 on H/R-suffered cardiomyocytes were based on the activation of the PI3K/AKT pathway. The abolishment of the PI3K/AKT via a pharmacological inhibitor (LY294002) repressed anti-H/R capabilities of SH2B1.

CONCLUSION

Therefore, SH2B1 prevents cardiomyocytes from inflammation, apoptosis and ROS in MIRI partially through the PI3K/AKT-dependent avenues. It may provide a novel therapeutic target for the treatment of MIRI.

Effects of intermittent hypoxia on cell survival and inflammatory responses in the intertidal marine bivalves Mytilus edulis and Crassostrea gigas

Hypoxia is a major stressor in estuarine and coastal habitats, leading to adverse effects in aquatic organisms. Estuarine bivalves such as blue mussels (Mytilus edulis) and Pacific oysters (Crassostrea gigas) can survive periodic oxygen deficiency but the molecular mechanisms that underlie cellular injury during hypoxia-reoxygenation are not well understood. We examined the molecular markers of autophagy, apoptosis and inflammation during short-term (1 day) and long-term (6 days) hypoxia and post-hypoxic recovery (1 h) in mussels and oysters by measuring the lysosomal membrane stability, activity of a key autophagic enzyme (cathepsin D) and mRNA expression of the genes involved in the cellular survival and inflammation, including caspase 2, 3 and 8, Bcl-2, BAX, TGF-β-activated kinase 1 (TAK1), nuclear factor kappa B1 (NF-κB) and NF-κB activating kinases IKKα and TBK1. Crassostrea gigas exhibited higher hypoxia tolerance, as well as blunted or delayed inflammatory and apoptotic response to hypoxia and reoxygenation as shown by the later onset and/or the lack of transcriptional activation of caspases, BAX and the inflammatory effector NF-κB, compared with M. edulis Long-term hypoxia resulted in upregulation of Bcl-2 in the oysters and mussels, implying activation of anti-apoptotic mechanisms. Our findings indicate the potential importance of the cell survival pathways in hypoxia tolerance of marine bivalves, and demonstrate the utility of the molecular markers of apoptosis and autophagy for the assessment of sublethal hypoxic stress in bivalve populations.

The Protection of Selenium Against Cadmium-Induced Mitochondrial Damage via the Cytochrome P450 in the Livers of Chicken

Cadmium (Cd) is a heavy metal in natural environment and has extreme toxicity. Selenium (Se) has protective effect against heavy metal-induced injury or oxidative stress. Cytochrome P450 (CYP450) enzymes are a family of hemoproteins primarily responsible for detoxification functions. In order to investigate whether CYP450 is related to the damage of livers caused by Cd exposure, we chose forty-eight 28-day-old healthy Hailan cocks for four groups: control group, Se group, Cd group, and Se + Cd group. After 90-day treatment, euthanized for experiment. Based on an established subchronic Cd poisoning model in chicken, this experiment was designed to detect mitochondrial structure, malondialdehyde (MDA), glutathione (GSH), DNA and protein crosslink (DPC) and protein carbonyl (PCO) content, the CYP450 and b₅ contents, the aminopyrine-N-demethylase (AND), erythromycin N-demethylase (ERND), aniline 4-hydroxylase (AH) and NADPH-cytochrome C reducatase (CR) activities, and mRNA expression level in the livers. The present results indicated that the MDA content, PCO content, and DPC index in Cd group were higher than those observed in other three groups. Most of the mitochondrial structure is incomplete in Cd group. The contents of CYP450 and b₅ were decreased in Cd group. The activities of AND, ERND, AH, and CR got reduced after Cd exposure, as observed in CYP450 gene expression. Our results showed that CYP450 system was involved in the entire process of injury and protection. This research provides a comprehensive evaluation of the oxidative stress effects of Cd related to CYP450 in chicken.

Novel Molecular Targets Participating in Myocardial Ischemia-Reperfusion Injury and Cardioprotection

Worldwide morbidity and mortality from acute myocardial infarction (AMI) and related heart failure remain high. While effective early reperfusion of the criminal coronary artery after a confirmed AMI is the typical treatment at present, collateral myocardial ischemia-reperfusion injury (MIRI) and pertinent cardioprotection are still challenging to address and have inadequately understood mechanisms. Therefore, unveiling the related novel molecular targets and networks participating in triggering and resisting the pathobiology of MIRI is a promising and valuable frontier. The present study specifically focuses on the recent MIRI advances that are supported by sophisticated bio-methodology in order to bring the poorly understood interrelationship among pro- and anti-MIRI participant molecules up to date, as well as to identify findings that may facilitate the further investigation of novel targets.

Intrinsic Effects of Gold Nanoparticles on Oxygen-Glucose Deprivation/Reperfusion Injury in Rat Cortical Neurons

This study aimed to investigate the potential effects of gold nanoparticles (Au-NPs) on rat cortical neurons exposed to oxygen-glucose deprivation/reperfusion (OGD/R) and to elucidate the corresponding mechanisms. Primary rat cortical neurons were exposed to OGD/R, which is commonly used in vitro to mimic ischemic injury, and then treated with 5- or 20-nm Au-NPs. We then evaluated cell viability, apoptosis, oxidative stress, and mitochondrial respiration in these neurons. We found that 20-nm Au-NPs increased cell viability, alleviated neuronal apoptosis and oxidative stress, and improved mitochondrial respiration after OGD/R injury, while opposite effects were observed for 5-nm Au-NPs. In terms of the underlying mechanisms, we found that Au-NPs could regulate Akt signaling. Taken together, these results show that 20-nm Au-NPs can protect primary cortical neurons against OGD/R injury, possibly by decreasing apoptosis and oxidative stress, while activating Akt signaling and mitochondrial pathways. Our results suggest that Au-NPs may be potential therapeutic agents for ischemic stroke.

Marine natural products for multi-targeted cancer treatment: A future insight

Cancer is world's second largest alarming disease, which involves abnormal cell growth and have potential to spread to other parts of the body. Most of the available anticancer drugs are designed to act on specific targets by altering the activity of involved transporters and genes. As cancer cells exhibit complex cellular machinery, the regeneration of cancer tissues and chemo resistance towards the therapy has been the main obstacle in cancer treatment. This fact encourages the researchers to explore the multitargeted use of existing medicines to overcome the shortcomings of chemotherapy for alternative and safer treatment strategies. Recent developments in genomics-proteomics and an understanding of the molecular pharmacology of cancer have also challenged researchers to come up with target-based drugs. The literature supports the evidence of natural compounds exhibiting antioxidant, antimitotic, anti-inflammatory, antibiotic as well as anticancer activity. In this review, we have selected marine sponges as a prolific source of bioactive compounds which can be explored for their possible use in cancer and have tried to link their role in cancer pathway. To prove this, we revisited the literature for the selection of cancer genes for the multitargeted use of existing drugs and natural products. We used Cytoscape network analysis and Search tool for retrieval of interacting genes/ proteins (STRING) to study the possible interactions to show the links between the antioxidants, antibiotics, anti-inflammatory and antimitotic agents and their targets for their possible use in cancer. We included total 78 pathways, their genes and natural compounds from the above four pharmacological classes used in cancer treatment for multitargeted approach. Based on the Cytoscape network analysis results, we shortlist 22 genes based on their average shortest path length connecting one node to all other nodes in a network. These selected genes are CDKN2A, FH, VHL, STK11, SUFU, RB1, MEN1, HRPT2, EXT1, 2, CDK4, p14, p16, TSC1, 2, AXIN2, SDBH C, D, NF1, 2, BHD, PTCH, GPC3, CYLD and WT1. The selected genes were analysed using STRING for their protein-protein interactions. Based on the above findings, we propose the selected genes to be considered as major targets and are suggested to be studied for discovering marine natural products as drug lead in cancer treatment.