Nitric Oxide Release Research Articles

Utilization of in-situ self-supporting materials for the preparation of flexible and stretchable electrodes for the detection of nitric oxide released from cells

Real-time monitoring of nitric oxide from endogenously cells released is crucial for revealing their physiological activities or pathological processes. However, designing electrochemical sensors for real-time monitoring at the cellular level is challenging due to the simultaneous requirements of sensitivity, transient recording capability, and biocompatibility. Combining the universally self-supported grown highly active materials with stretchable conductive flexible substrates holds promise for achieving sensitive detection of cells and real-time monitoring of mechanically induced biomolecular release. However, existing manufacturing strategies for highly sensitive stretchable flexible electrochemical sensors still face significant challenges due to low material activity, high processing requirements, and the complexity of further designing membrane electrodes. Here, we designed a method of in-situ self-supported growth to grow Co-doped Ni(OH)2 structures on rigid Ti foil. Leveraging the synergistic effect of Co and Ni, sensitive detection of NO was achieved, enabling real-time monitoring of trace amounts of NO released by Raw 264.7 cells. Based on this material, using catalytic ink method, it was transferred to low-resistance flexible ITO film (LIF), enabling real-time monitoring of mechanically induced NO release from Human Umbilical Vein Endothelial Cells (HUVECs) cells.

Neuroprotection of isoorientin against microglia activation induced by lipopolysaccharide via regulating GSK3β, NF-κb and Nrf2/HO-1 pathways

Background: Isoorientin (ISO), a flavone C-glycoside, is a glycogen synthase kinase 3β (GSK3β) substrate-competitive inhibitor. ISO has potential in treatment of Alzheimer’s disease (AD). An excessive activation of GSK3β can lead to neuroinflammation causing neuronal damage. Microglia cells, as resident immune cells of the central nervous system, mediate neuroinflammation. Here, we studied the effects of ISO on microglial activation to alleviate neuroinflammation. Methods: Effects of ISO were observed upon the stimulation of mouse microglia BV2 or SIM-A9 cells by lipopolysaccharide (LPS). Lithium chloride (LiCl) was the positive control as a GSK3β inhibitor. The release of TNF-α and NO were analyzed by ELISA and Griess assays, while expressions of COX-2, Iba-1, BDNF, GSK3β, NF-κB p65, IκB, Nrf2 and HO-1 were detected by Western blotting. In the co-culture model of SIM-A9 cells and differentiated SH-SY5Y human neuroblastoma cells, effects of ISO on microglia-mediated neuronal damage were evaluated with the MTS assay. Results: ISO significantly inhibited the production of TNF-α (p < 0.01), NO (p < 0.001) and the expression of COX-2 (p < 0.01) and Iba-1 (p < 0.05) induced by LPS, and increased BDNF. The cell viability of SH-SY5Y was inhibited by LPS in the co-culture, which was prevented by ISO pretreatment. ISO increased the expression of p-GSK3β (Ser9), IκB and HO-1 in the cytoplasm, decreased NF-κB p65 and increased Nrf2 in the nucleus compared with the LPS group. Conclusion: ISO attenuated the activation of microglia through regulating the GSK3β, NF-κB and Nrf2/HO-1 signaling pathways to exert neuroprotection.

Inhibitory Effect of Cayratia albifolia C. L. Li Extract on LPS-induced Inflammation of RAW264.7 Cells by Regulating the Nrf2/HO-1 Axis

Background: Cayratia albifolia C. L. Li (Jiao Mei Gu (JMG)) has potential therapeutic effects in inflammatory diseases. Purpose: The primary goal of the research was to focus on the antioxidant and anti-inflammatory qualities of C. albifolia and the underlying mechanisms that contribute to these benefits. Methods: To explore the anti-inflammatory abilities of JMG, we employed enzyme-linked immunosorbent assay and nitric oxide (NO) assay in a lipopolysaccharide (LPS)-induced macrophage inflammation model. Furthermore, flow cytometry was employed to assess the antioxidant effects of C. albifolia, and Western blotting was used to reveal the underlying mechanisms. Results: Ethyl acetate extract of C. albifolia effectively reduced the release of NO, interleukin-6, tumor necrosis factor-α, and prostaglandin E2 in macrophages. Additionally, it prevented the expression of reactive oxygen species. Mechanistically, the extract may downregulate the expression of inducible nitric oxide synthase, cyclooxygenase-2, the nuclear factor-erythroid 2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) protein expression. Conclusion: The ethyl acetate extract of C. albifolia demonstrated remarkable anti-inflammatory and antioxidant effects by modulating the Nrf2/HO-1 axis.

Self-Assembled Nanoparticles of Silicon (IV)-NO Donor Phthalocyanine Conjugate for Tumor Photodynamic Therapy in Red Light.

The combination of photodynamic therapy (PDT) and pneumatotherapy is emerging as one of the most effective strategies for increasing cancer treatment efficacy while minimizing side effects. Photodynamic forces affect nitric oxide (NO) levels as activated photosensitizers produce NO, and NO levels in the tumor and microenvironment directly impact tumor cell responsiveness to PDT. In this paper, 3-benzenesulfonyl-4-(1-hydroxy ether)-1,2,5-oxadiazole-2-oxide NO donor-silicon phthalocyanine coupling (SiPc-NO) was designed and prepared into self-assembled nanoparticles (SiPc-NO@NPs) by precipitation method. By further introducing arginyl-glycyl-aspartic acid (RGD) on the surface of nanoparticles, NO-photosensitizer delivery systems (SiPc-NO@RGD NPs) with photo-responsive and tumor-targeting properties were finally prepared and preliminarily evaluated in terms of their formulation properties, NO release, and photosensitizing effects. Furthermore, high reactive oxygen species (ROS) generation efficiency and high PDT efficiency in two breast cancer cell lines (human MCF-7 and mouse 4T1) under irradiation were also demonstrated. The novel SiPc-NO@RGD NPs show great potential for application in NO delivery and two-photon bioimaging-guided photodynamic tumor therapy.

Polarized benzene rings can promote the interaction between CaM and the CaMBD region of nNOS.

The neuronal nitric oxide synthase (nNOS) subtype of nitric oxide synthase (NOS) is an enzyme required for learning and memory. Overactivation of nNOS can lead to oxidative/nitrite stress, which is complicit in the pathophysiology of various neurological and psychiatric disorders. Previous studies have shown that calmodulin (CaM) forms complexes with Ca2+ and binds to the calmodulin-binding domain (CaMBD) of nNOS, thereby upregulating its catalytic activity in hippocampal neurons. To date, there has been no explanation for the non-covalent interactions in the CaMBD-CaM binding structure model of nNOS. In this study, we aimed to investigate the intrinsic factors involved in the binding of CaM to NOS-CaMBD and designed interfering peptides based on the N0 peptide structure of the original nNOS-CaMBD sequence: N1 (obtained from the L734F mutation), N2 (obtained from the F731Y and F740Y mutations), and N3 (obtained from the F731L, V738L, and F740L mutations). We employed homology modeling to construct six CaM-peptide complex models, aiming to elucidate the roles of key amino acid residues within the N0 peptide in its interaction with CaM by means of molecular dynamics simulations. The effect of the peptides on the activation and release of NO by nNOS in neurons was assessed using murine primary neuronal cells. When measuring neuronal NO content, it was found that adding N2 and N3 to cultivated neurons significantly increased nNOS activity, leading to the increased NO production. We found that interfering peptides could stably bind to CaM. Among them, N2 and CaM exhibited the strongest binding ability, indicating that the polarized benzene ring significantly enhanced the binding between nNOS-CaMBD and CaM. Conversely, the binding ability between N0 and CaM was the weakest, as they exhibited the worst polar contact, weakest hydrogen bonding, and the lowest binding free energy. The simulation results also highlighted several important amino acid residues: The K76 of CaM plays an important role in polar contact and hydrogen bonding formation, the L734 residue suppressed model flexibility to a certain extent and had an adverse effect on the overall binding free energy of the model. These results, compared with the results of cellular NO content, a preliminary verification of the antagonistic competitive mechanism between CaM allosteric activation of nNOS and SUMOylation hyperactivation was performed. In summary, this study explored the ability and mode of action of key residues in nNOS-CaMBD on the binding of interfering peptides to CaM, thereby providing new structural perspectives for the activation of nNOS by CaM and recommendations for drug design targeting the specific inhibition of nNOS.

Bimetal-Biligand Frameworks for Spatiotemporal Nitric Oxide-Enhanced Sono-Immunotherapy.

Sonodynamic therapy can trigger immunogenic cell death to augment immunotherapy, benefiting from its superior spatiotemporal selectivity and non-invasiveness. However, the practical applications of sonosensitizers are hindered by their low efficacy in killing cancer cells and activating immune responses. Here, two US Food and Drug Administration-approved drug ligands (ferricyanide and nitroprusside) and two types of metals (copper/iron) are selected to construct a bimetal-biligand framework (Cu[PBA-NO]). Through elaborate regulation of multiple metal/ligand coordination, the systemically administered Cu[PBA-NO] nanoagent shows sono-catalytic and NO release ability under ultrasound irradiation, which can be used for effective sono-immunotherapy. Moreover, Cu[PBA-NO] can downregulate intracellular glutathione levels that would destroy intracellular redox homeostasis and facilitate reactive oxygen species accumulation. The released tumor-associated antigens subsequently facilitate dendritic cell maturation within the tumor-draining lymph node, effectively initiating a T cell-mediated immune response and thereby bolstering the capacity to identify and combat cancer cells. This study paves a new avenue for the efficient cancer sono-immunotherapy.

Cytotoxic and pro-oxidant profile of a photosensitive ruthenium nitrosyl candidate for NO delivery in healthy human fibroblasts.

Ruthenium nitrosyl (Ru-NO) complexes are of interest as photoactive nitric oxide (NO) donor candidates for local therapeutic applications. NO plays a crucial regulatory role in skin homeostasis, concentration-dependently affecting processes like the proliferation, apoptosis, autophagy and redox balance. In this context, we investigated HE-10, a ruthenium-based photoinducible NO donor, for its pro-oxidant and cytotoxic effects under light and dark conditions in VH10 human foreskin fibroblast cells. We also tested its intracellular and extracellular NO-releasing function. Our study reveals a significant dose-dependent cytotoxic effect of HE-10, an increase in intracellular reactive oxygen and nitrogen species, and the occurrence of apoptosis in skin fibroblast cells. Furthermore, exposure to both increasing doses of HE-10 and white LED light led to substantial cellular events, including a significant induction of autophagy and G2/M phase cell cycle arrest. Paradoxically, these effects were not solely attributable to NO release based on DAF2-DA NO probe results, suggesting that intracellular photochemical reactions additional to NO photolysis contribute to HE-10's biological activity. This study shows that HE-10 exhibits both cytotoxic and potential therapeutic effects, depending on concentration and light exposure. These findings are crucial for developing targeted Ru-NO complex treatments for skin diseases and potentially certain types of skin cancer, where controlled NO release could be beneficial.

Anti-inflammatory Effect of Novel 2-Phenylphthalazin-2-ium Bromides on LPS-induced RAW264.7 Cells and their Mechanism

Background: Inspired by natural anti-inflammatory quaternary benzo[C]phenanthridine alkaloids, novel 2-phenylphthalazin-2-ium bromides were previously designed and synthesized. Objective: The anti-inflammatory effect of 2-phenylphthalazin-2-ium bromides was evaluated based on inflammatory cytokines, and their possible mechanism was explored through the NF-κB, TLR4 and MAPK signaling pathways. Methods: The tested concentrations of two compounds were assessed using MTT assay in vitro. Griess assay was used to determine the changes in nitric oxide (NO) in the cell culture supernatant. qRT‒PCR was used to detect the mRNA levels of inflammatory cytokines, such as IL-6, IL-1ß, IL-10, TNF-α, TLR4 and iNOS. The secretion levels of TNF-α and IL-1β were detected by ELISA. Western blot test was used to detect the protein expression of IL-6, IL-10, TLR4, iNOS, NF-κB, p-P38/P38, p- ERK/ERK and p-JNK/JNK. Results: 2-(3,5-Dichlorophenyl)phthalazin-2-ium bromide (2) with a concentration below 1 μg/mL showed no significant effect on the growth inhibition of RAW264.7 cells, so the concentrations of compound 2 used for experiments were set to 0, 0.25, 0.5 and 1 μg/mL. Compared with the blank control group, the model group showed increased release of NO, transcription levels of IL-6, IL-1ß, IL-10, TNF-α, TLR4 and iNOS (p&lt; 0.05), and ratios of p-P38/P38, p-ERK/ERK, p-JNK/JNK (p&lt; 0.05). Compared with the model group, the sample groups displayed decreased NO release and reduced transcriptional levels of IL-6, IL-1ß, IL-10, TNF-α, TLR4, and iNOS and reduced protein expression ratios of IL-6, IL-1ß, IL-10, TNF-α, NF-κB, TLR4, iNOS, p-P38/P38, p-ERK/ERK and p- JNK/JNK (p&lt; 0.05). Conclusion: This study showed that 2-phenylphthalazin-2-ium bromides partially protected macrophages from the LPS-induced inflammatory response by suppressing TLR4-NF-κB/MAPK signaling and reducing NO production.

Abstract P309: Vasodilating Effects of Macrolides: ex vivo and in vivo study

Background: Anecdotal reports showed a decrease in blood pressure (BP) values in subjects assuming macrolide antibiotics when co-administered with calcium channel blockers. Recently, in the MAPA study, in patients with primary hypertension given a single dose of macrolide a decrease in BP was observed. However, whether macrolides induce per se vasorelaxation remains unknown. Aim: To investigate if macrolides induce vasorelaxation and to identify the underlying mechanisms. Methods: The effects of 3 macrolides (roxithromycin, azithromycin, clarithromycin) were investigated in a wire myograph in aortas isolated from C57BL/6J mice, following standard protocols. Relaxation/contraction was evaluated in phenylephrine pre-contracted aorta segments exposed to different macrolide concentrations [10 -10 M to 10 -5 M]. Longer-term effects of azithromycin (50 mg/Kg/d intraperitoneally for 14 days) were investigated in vivo in a mouse model of Ang II-induced hypertension. BP was measured with the tail-cuff method; functional and structural/mechanical properties of the aorta and mesenteric arteries were evaluated with wire or pressure myograph, as appropriate. Results: After exposure to macrolides, phenylephrine pre-contracted mice aorta segments showed relaxation (maximum effect: -15-20% vs DMSO). The vasodilating effect was abolished by the removal of the endothelium, and was blunted by L-NAME. In the vivo studies treatment with azithromycin lowered BP values and prevented Ang II-induced endothelial dysfunction. Conclusions: Macrolides exert a vasodilatory action that involves endothelium-dependent NO release. In a model of Ang II-mediated hypertension, azithromycin exerted a BP-lowering effect.

Ginsenoside Rh4 prevents endothelial dysfunction as a novel AMPK activator.

The AMP-activated protein kinase (AMPK) signalling pathway is a desirable target for various cardiovascular diseases (CVD), while the involvement of AMPK-mediated specific downstream pathways and effective interventions in hyperlipidaemia-induced endothelial dysfunction remain largely unknown. Herein, we aim to identify an effective AMPK activator and to explore its efficacy and mechanism against endothelial dysfunction. Molecular docking technique was adopted to screen for the potent AMPK activator among 11 most common rare ginsenosides. In vivo, poloxamer 407 (P407) was used to induce acute hyperlipidaemia in C57BL/6J mice. In vitro, palmitic acid (PA) was used to induce lipid toxicity in HAEC cells. We discovered the strongest binding of ginsenoside Rh4 to AMPKα1 and confirmed the action of Rh4 on AMPK activation. Rh4 effectively attenuated hyperlipidaemia-related endothelial injury and oxidative stress both in vivo and in vitro and restored cell viability, mitochondrial membrane potential and mitochondrial oxygen consumption rate in HAEC cells. Mechanistically, Rh4 bound to AMPKα1 and simultaneously up-regulated AKT/eNOS-mediated NO release, promoted PGC-1α-mediated mitochondrial biogenesis and inhibited P38 MAPK/NFκB-mediated inflammatory responses in both P407-treated mice and PA-treated HAEC cells. The AMPK inhibitor Compound C treatment completely abrogated the regulation of Rh4 on the above pathways and weakened the lowering effect of Rh4 on endothelial impairment markers, suggesting that the beneficial effects of Rh4 are AMPK dependent. Rh4 may serve as a novel AMPK activator to protect against hyperlipidaemia-induced endothelial dysfunction, providing new insights into the prevention and treatment of endothelial injury-associated CVD.

Abstract P229: Neurovascular and Cognitive Dysfunction in Hypertension at the Single-Cell Level

Hypertension (HTN) is the leading cause of vascular cognitive impairment, which has been attributed to altered microvascular regulation, neural network dysfunction and white matter (WM) damage. However, the neurovascular cells and cellular networks through which microvascular alterations lead to neuronal dysfunction and WM damage require elucidation. We employed unbiased single-cell RNA sequencing of the neocortex in 10-week-old C57BL/6 male mice treated with AngII (600ng/kg/min s.c.) or vehicle, to map out the transcriptomic changes induced by HTN. Transcriptomes (3 mice/group) were obtained for 39,451 cells before (day 3 after AngII) and after development of neurovascular and cognitive dysfunction (day 42). Profound transcriptional alterations were already seen at day 3 in venular endothelial cells (EC), GABAergic interneurons expressing neuronal nitric oxide synthase (nNOS), and oligodendrocyte precursors (OPC) (EdgeR; FDR&lt; 0.05, logFC&gt; 2). Gene ontology (GO) analysis (p &lt;0.05) revealed terms consistent with senescence of venular EC, validated by immunolabeling with senescence markers (β-galactosidase, p27, p21, p16). GO also flagged terms reflecting suppression of neuronal NO synthesis and synaptic dysfunction in interneurons, which were confirmed by demonstrating reduced NMDA-evoked NO release in brain slices (20±0.03% Veh vs. 0±0.03% AngII;p&lt;0.0001;n=60 neurons from 5 slices/group) and loss of the vesicular GABA transporter, VGAT. In addition, GO revealed early impairments in OPC differentiation, which could underlie later WM disruption. Consistent with this prediction, transcripts suggestive of impaired myelination were overrepresented at 42 days in mature oligodendrocytes (e.g., Hes5 ), and these WM alterations were confirmed in vivo by an increase in internodal distance (Nav1.6/CASPR) in axons (0.09±0.014 µm 3 Veh vs. 0.16±0.01 µm 3 AngII;n=4/group;p&lt;0.05). Ligand-receptor interaction analysis (CellChat) indicated molecular reprogramming of oligodendrocytes by senescent EC via suppression of signaling promoting myelination (CD39-AdeRA1) and upregulation of signaling arresting OPC development (Endothelin-ER2). These data reveal a previously unappreciated susceptibility of venular EC, OPC and nNOS interneurons to the deleterious effects of AngII HTN, and point to a novel pathogenic interaction between senescent EC and OPC, as well as to early nNOS interneuron dysfunction, the disease relevance and therapeutic potential of which requires validation.

Evaluation of Withania somnifera based supplement for immunomodulatory and antiviral properties against viral infection

BackgroundViral mediated diseases are continuously posing potent threat to human health. Nutraceuticals are being employed as novel therapeutics during viral outbreaks. MAM granules consist of Curcuma longa, Withania somnifera, and Piper nigrum, is one such patented Siddha nutraceutical supplement that has been proposed to be a therapeutic agent against viral diseases. ObjectiveWe characterised MAM for their phytochemical and physicochemical properties and evaluated its cytotoxicity via in vivo acute toxicity studies using Wistar rats and by cell-based MTT assays. Materials and MethodsThe antiviral properties of the aqueous extract of MAM were investigated against SARS-CoV-2 and chikungunya virus (CHIKV). Further, using ABTS radical scavenging, SOD enzymatic assays and measurement of intracellular ROS, we investigated the antioxidant potential of MAM extract and its ingredients in RAW264.7 cells. Additionally, production of inflammatory mediators was evaluated via NO release, PGE2 production and release of pro-inflammatory cytokines (IL-1β and TNFα). ResultsThe MAM granules and aqueous extracts demonstrated no significant toxicity and demonstrated potent antiviral activity during co-incubation assay with SARS-CoV-2 and CHIKV. Moreover, we observed potent antioxidant and anti-inflammatory activity of MAM extract in a dose dependent manner. Further investigations on the individual ingredients with respect to their antioxidant and anti-inflammatory activities showed that all ingredients contributed synergistically and Withania somnifera showed most potent anti-oxidant activity. ConclusionThe overall in vitro, and in vivo analysis demonstrated that MAM granules were non-toxic and possessed potent antiviral activity. Additionally, observed significant anti-oxidant and anti-inflammatory properties of MAM suggested the modulation of innate immune response in the host validating its use as an effective nutraceutical during viral outbreaks.

Therapeutic Effect of Padina arborescens Extract on a Cell System Model for Parkinson's Disease.

Leucine-rich repeat kinase 2 (LRRK2) and α-synuclein are involved in the pathogenesis of Parkinson's disease. The activity of LRRK2 in microglial cells is associated with neuroinflammation, and LRRK2 inhibitors are crucial for alleviating this neuroinflammatory response. α-synuclein contributes to oxidative stress in the dopaminergic neuron and neuroinflammation through Toll-like receptors in microglia. In this study, we investigated the effect of the marine alga Padina arborescens on neuroinflammation by examining LRRK2 activation and the aggregation of α-synuclein. P. arborescens extract inhibits LRRK2 activity in vitro and decreases lipopolysaccharide (LPS)-induced LRRK2 upregulation in BV2, a mouse microglial cell line. Treatment with P. arborescens extract decreased tumor necrosis factor-α (TNF-α) gene expression by LPS through LRRK2 inhibition in BV2. It also attenuated TNF-α gene expression, inducible nitric oxide synthase, and the release of TNF-α and cellular nitric oxide in rat primary microglia. Furthermore, P. arborescens extract prevented rotenone (RTN)-induced oxidative stress in primary rat astrocytes and inhibited α-synuclein fibrilization in an in vitro assay using recombinant α-synuclein and in the differentiated human dopaminergic neuronal cell line SH-SY5Y (dSH). The extract increased lysosomal activity in dSH cells. In addition, P. arborescens extract slightly prolonged the lifespan of Caenorhabditis elegans, which was reduced by RTN treatment.

Deciphering Molecular Mechanisms of Carbon Tetrachloride- Induced Hepatotoxicity: A Brief Systematic Review.

The liver plays a critical role in metabolic processes, making it vulnerable to injury. Researchers often study carbon tetrachloride (CCl4)-induced hepatotoxicity in model organisms because it closely resembles human liver damage. This toxicity occurs due to the activation of various cytochromes, including CYP2E1, CYP2B1, CYP2B2, and possibly CYP3A, which produce the trichloromethyl radical (CCl3*). CCl3* can attach to biological molecules such as lipids, proteins, and nucleic acids, impairing lipid metabolism and leading to fatty degeneration. It can also combine with DNA to initiate hepatic carcinogenesis. When exposed to oxygen, CCl3* generates more reactive CCl3OO*, which leads to lipid peroxidation and membrane damage. At the molecular level, CCl4 induces the release of several inflammatory cytokines, including TNF-α and NO, which can either help or harm hepatotoxicity through cellular apoptosis. TGF-β contributes to fibrogenesis, while IL-6 and IL-10 aid in recovery by minimizing anti-apoptotic activity and directing cells toward regeneration. To prevent liver damage, different interventions can be employed, such as antioxidants, mitogenic agents, and the maintenance of calcium sequestration. Drugs that prevent CCl4- induced cytotoxicity and proliferation or enhance CYP450 activity may offer a protective response against hepatic carcinoma.

The Effect of Lipopolysaccharide Challenge in RAW 264.7 Cells on Nitric Oxide Release and Cell Viability

Lipopolysaccharide (LPS) is a major component of a gram-negative bacterial wall that is widely used and well-established to induce inflammation in vitro. In addition, the in vitro model using RAW 264.7 cells is the most commonly applied in screening the anti-inflammatory and elucidating the pathophysiology of inflammation-based disease, as well. However, there is still limited data on the efficacy of different doses of LPS in inducing inflammation in RAW 264.7 cells. This study aimed to evaluate the effect and safety of LPS at various doses in RAW 264.7 cells. RAW 264.7 cells were exposed to LPS at different dose ranges (10ng/mL-10µg/mL) for 24 hours. The nitric oxide (NO) release as inflammatory responses and viability test were evaluated using Griess assay and CCK-8 assays, respectively. The result showed that NO production was increased at different doses of LPS compared to the control although not significant. Whereas, All LPS-treated RAW 264.7 cells tended to increase but not significantly compared to the control groups. This study showed that the LPS treatment effectively induced inflammation in RAW 264.7 cells as shown by NO production and was considerably safe as the viability was comparable between LPS and control group for RAW cells 264.7 at least up to 10µg/mL for 24 hours.

Nitrite reductase-mimicking catalysis temporally regulating nitric oxide concentration gradient adaptive for antibacterial therapy.

The unique bacterial infection microenvironment (IME) usually requires complicated design of nanomaterials to adapt to IME for enhancing antibacterial therapy. Here, an alternative IME adaptative nitrite reductase-mimicking nanozyme is constructed by in situ growth of ultrasmall copper sulfide clusters on the surface of a nanofibrillar lysozyme assembly (NFLA/CuS NHs), which can temporally regulate nitric oxide (NO) gradient concentration to kill bacteria initially and promote tissue regeneration subsequently. Benefiting from a copper nitrite reductase (CuNIR)-inspired structure with CuS cluster as active center and NFLA as skeleton, NFLA/CuS NHs efficiently boost the catalytic reduction of nitrite to NO. The inherent supramolecular fibrillar networks displays excellent bacterial capture capability, facilitating initial high-concentration NO attacks on the bacteria. The subsequent catalytic release of low-concentration NO by NFLA/CuS NHs-mediated nitrite reduction remarkably promotes cell migration and angiogenesis. This work paves the way for dynamically eliminating MDR bacterial infection and promoting tissue regeneration in a simple and smart way through CuNIR-mimicking catalysis.

Discovery of Bioactive Terpenes Derived from a Polar Fungus.

Polar fungi play a vital role as prolific sources of unique chemical structures and diverse bioactive compounds. Eutypella sp. D-1 is a fungus isolated from the Arctic, and six compounds were extracted from the fermentation broth. Their structures are elucidated from HRESIMS, NMR spectroscopy, and ECD calculations. Compounds 1-5 are newly discovered compounds, with compound 1 possessing a rare peroxide-bridge structure. Compounds 1-4 are categorized as pimarane-type diterpenes, while compounds 5 and 6 belong to the eudesmanolide sesquiterpenes. Compound 4 demonstrates anti-inflammatory activity by inhibiting lipopolysaccharide-induced nitric oxide release in RAW264.7 cells. Compound 4 and 5 show antibacterial activity against Escherichia coli and Staphylococcus aureus.

Constructing sodium alginate/carboxymethyl chitosan coating capable of catalytically releasing NO or CO for improving the hemocompatibility and endothelialization of magnesium alloys

Although significant progress in developing biodegradable magnesium alloy materials in cardiovascular stents has been achieved recently, they still face challenges such as rapid in vivo corrosion degradation, inferior blood compatibility, and limited re-endothelialization after the implantation. Hydrogel coating that can catalyze the liberation of gas signal molecules offers a good solution to alleviate the corrosion rate and enhance the biocompatibility of magnesium and its alloys. In this study, based on alkaline heat treatment and construction of polydopamine coating on the surface of magnesium alloy, sodium alginate/carboxymethyl chitosan (SA/CMCS) gel was simultaneously covalently grafted onto the surface to build a natural polymer hydrogel coating, and selenocystamine (SeCA) and CO release molecules (CORM-401) were respectively immobilized on the surface of the hydrogel coating to ameliorate the anticoagulant performance and accelerate endothelial cells (ECs) growth by catalyzing the release of endogenous gas signal molecules (NO or CO). The findings verified that the as-prepared hydrogel coating can catalyze the liberation of CO or NO and significantly improve the corrosion resistance of magnesium alloy. At the same time, owing to the excellent hydrophilicity of the hydrogel coating, the good anticoagulant property of sodium alginate, and the ability of CMCS to promote the ECs growth, the modified magnesium alloy could significantly improve the albumin adsorption while preventing the adsorption of fibrinogen, hence significantly augmenting the anticoagulant properties and promoting the ECs growth. Under the catalytic release of NO or CO, the released gas molecules further enhanced hemocompatibility and promoted endothelial cell (EC) growth and the expression of vascular endothelial growth factor (VEGF) and NO of ECs. Therefore, the bioactive coatings that can catalyze the release of NO or CO have potential applications in constructing surface bioactive coatings for magnesium alloy materials used for intravascular stents.

Ibuprofen‑derived nitric oxide donors with a high affinity to human serum albumin induce cell death in pancreatic cancer cells through a non‑caspase 3/7‑mediated pathway.

Nitric oxide (NO) has been reported to have a cytotoxic effect on various types of cancer. However, the efficient delivery of NO donors to tumors remains challenging. The present study used ibuprofen, which has a high binding affinity to human serum albumin (HSA). A total of two types of nitrated forms of ibuprofen, 4-[(nitrooxy)methyl]benzyl 2-(4-isobutylphenyl)propanoate [nitrated ibuprofen benzyl linker (NIB)] and 2-(nitrooxy)ethyl 2-(4-isobutylphenyl) propanoate [nitrated ibuprofen ethyl linker (NIE)], were synthesized. It was demonstrated that both NIB and NIE bound to the ibuprofen-binding site of HSA. Although NOx release was observed from NIB, but not NIE, intracellular NO release was detected from both NIB and NIE, which indicated that the mechanisms of NO release may be different for NIB and NIE. Both NIB and NIE induced concentration- and time-dependent cell death in human pancreatic cancer cells, whereas this cell death was not observed with ibuprofen, which could suggest that these cell death-inducing effects may be mediated by NO. The non-specific caspase inhibitor, z-VAD-FMK, inhibited cell death induced by NIB and NIE, but activation of caspase 3/7 was not observed. These results suggested that both NIB and NIE induced cell death through a non-caspase 3/7 pathway. The findings of the present study demonstrated that both NIB and NIE, as NO donors that could be retained in blood, may potentially be useful anti-cancer agent candidates in the future.

Spatially confined photoacoustic effects of responsive nanoassembly boosts lysosomal membrane permeabilization and immunotherapy of triple-negative breast cancer

Although immunogenic cell death (ICD) induced by lysosomal membrane permeabilization (LMP) evidently enhance the effectiveness of antitumor immunity for triple-negative breast cancer (TNBC) with poor immunogenicity, their potential is increasingly restricted by the development of other death pathways and the repair of lysosomes by endoplasmic reticulum (ER) during LMP induction. Herein, a polydopamine nanocomposite with i-motif DNA modified and BNN6 loaded is prepared toward boosting LMP and immunotherapy of TNBC by synergy of spatially confined photoacoustic (PA) effects and nitric oxide. Combining the high-frequency pulsed laser (4000 kHz) with the intra-lysosomal assembly of nanocomposites produced spatially confined and significantly boosted PA effects (4.8-fold higher than the individually dispersed particles extracellular), suppressing damage to other cellular components and selectively reducing lysosomal integrity to 19.2 %. Simultaneously, the releasing of nitric oxide inhibited the repair of lysosomes by ER stress, causing exacerbated LMP. Consequently, efficient immune activation was achieved, including the abundant releasing of CRT/HMGB1 (5.93–6.8-fold), the increasing maturation of dendritic cells (3.41-fold), and the fostered recruitment of CD4+/CD8+T cells (3.99–3.78-fold) in vivo. The study paves a new avenue for the rational design and synergy of confined energy conversion and responsive nanostructures to achieve the treatment of low immunogenicity tumors. Statement of significanceA strategy of boosting lysosomal membrane permeabilization (LMP) and concomitantly preventing the repair was developed to address the immunotherapy challenge of triple-negative breast cancer. Spatially confined and significantly enhanced photoacoustic (PA) effects were achieved through DNA-guided pH-responsive assembly of polydopamine nanocomposites in lysosomes and application of a high-frequency pulsed laser. Efficient immunogenic cell death was guaranteed by selective and powerful damage of lysosomal membranes through the significant contrast of PA intensities for dispersed/assembled particles and nitric oxide release induced endoplasmic reticulum stress. The study paves a new avenue for the rational design and synergy of confined energy conversion and responsive nanostructures to achieve the treatment of low immunogenicity tumors.