2-(4-Methylthiazol-5-yl) Ethyl Nitrate Hydrochloride Ameliorates Cognitive Impairment via Modulation of Oxidative Stress and Nuclear Factor Kappa B (NF-κB) Signaling Pathway in Chronic Cerebral Hypoperfusion-Associated Spontaneously Hypertensive Rats.

Hypertension reduces the bioavailability of vascular nitric oxide (NO) and contributes to the onset of vascular dementia (VaD). A loss of NO bioavailability increases inflammation and oxidative stress. 2-(4-Methylthiazol-5-yl) ethyl nitrate hydrochloride (W1302) is a novel nitric oxide donor (NOD) which is undergoing phase I clinical trials in China for the treatment of VaD. In this study, we investigated the protective effects of W1302 in VaD rats induced by the permanent occlusion of a bilateral common carotid arteries model related to spontaneous hypertension (SHR-2VO), and we further explored the underlying mechanisms. Nimodipine was used as a positive control. Our results showed that W1302 treatment for 4 weeks (10 mg/Kg/day) exhibited stronger improvement in the spatial learning and memory deficits in SHR-2VO rats compared with nimodipine with slightly lower systolic blood pressure (SBP). Meanwhile, W1302 treatment significantly increased NO and cGMP production, restored mitochondrial membrane potential and attenuated oxidative stress as evidenced by increasing ATP production and reducing malondialdehyde (MDA) levels in the brain. Furthermore, W1302 treatment markedly inhibited the iNOS activity and decreased TNF-α expression via inhibiting the nuclear factor kappa B (NF-κB) signaling pathway. Nimodipine treatment also restored these aberrant changes, but its ATP production was weaker than that of W1302, and there was no significant effect on NO release. Taken together, W1302 exhibited beneficial effects on complications in VaD with hypertension, which is involved in suppressing oxidative damage, and the inflammatory reaction might be mediated by an increase in NO release. Therefore, W1302 has therapeutic potential for the treatment of VaD caused by chronic cerebral hypoperfusion-associated spontaneous hypertension.

Photothermal-controlled NO-releasing Nanogels reverse epithelial-mesenchymal transition and restore immune surveillance against cancer metastasis.

Metastasis leads to high mortality among cancer patients. It is a complex, multi-step biological process that involves the dissemination of cancer cells from the primary tumor and their systemic spread throughout the body, primarily through the epithelial-mesenchymal transition (EMT) program and immune evasion mechanisms. It presents a challenge in how to comprehensively treat metastatic cancer cells throughout the entire stage of the metastatic cascade using a simple system. Here, we fabricate a nanogel (HNO-NG) by covalently crosslinking a macromolecular nitric oxide (NO) donor with a photothermal IR780 iodide-containing hyaluronic acid derivative via a click reaction. This enables stable storage and tumor-targeted, photothermia-triggered release of NO to combat tumor metastasis throughout all stages. Upon laser irradiation (HNO-NG+L), the surge in NO production within tumor cells impairs the NF-κB/Snail/RKIP signaling loop that promotes the EMT program through S-nitrosylation, thus inhibiting cell dissemination from the primary tumor. On the other hand, it induces immunogenic cell death (ICD) and thereby augments anti-tumor immunity, which is crucial for killing both the primary tumor and systemically distributed tumor cells. Therefore, HNO-NG+L, by fully leveraging EMT reversal, ICD induction, and the lethal effect of NO, achieved impressive eradication of the primary tumor and significant prevention of lung metastasis in a mouse model of orthotropic 4T1 breast tumor that spontaneously metastasizes to the lungs, extending the NO-based therapeutic approach against tumor metastasis.

Influence of diimine bidentate ligand in the nitrosyl and nitro terpyridine ruthenium complex on the HSA/DNA interaction and antiviral activity.

Nitric oxide (NO) acts in different physiological processes, such as blood pressure control, antiparasitic activities, neurotransmission, and antitumor action. Among the exogenous NO donors, ruthenium nitrosyl/nitro complexes are potential candidates for prodrugs, due to their physicochemical properties, such as thermal and physiological pH stability. In this work, we proposed the synthesis and physical characterization of the new nitro terpyridine ruthenium (II) complexes of the type [RuII(L)(NO2)(tpy)]PF6 where tpy = 2,2':6',2″-terpyridine; L = 3,4-diaminobenzoic acid (bdq) or o-phenylenediamine (bd) and evaluation of influence of diimine bidentate ligand NH.NHq-R (R = H or COOH) in the HSA/DNA interaction as well as antiviral activity. The interactions between HSA and new nitro complexes [RuII(L)(NO2)(tpy)]+ were evaluated. The Ka values for the HSA-[RuII(bdq)(NO2)(tpy)]+ is 10 times bigger than HSA-[RuII(bd)(NO2)(tpy)]+. The sites of interaction between HSA and the complexes via synchronous fluorescence suppression indicate that the [RuII(bdq)(NO2)(tpy)]+ is found close to the Trp-241 residue, while the [RuII(bd)(NO2)(tpy)]+ complex is close to Tyr residues. The interaction with fish sperm fs-DNA using direct spectrophotometric titration (Kb) and ethidium bromide replacement (KSV and Kapp) showed weak interaction in the system fs-DNA-[RuII(bdq)(NO)(tpy)]+. Furthermore, fs-DNA-[RuII(bd)(NO2)(tpy)]+ and fs-DNA-[RuII(bd)(NO)(tpy)]3+ system showed higher intercalation constant. Circular dichroism spectra for fs-DNA-[RuII(bd)(NO2)(tpy)]+ and fs-DNA-[RuII(bd)(NO)(tpy)]3+, suggest semi-intercalative accompanied by major groove binding interaction modes. The [RuII(bd)(NO2)(tpy)]+ and [RuII(bd)(NO)(tpy)]3+ inhibit replication of Zika and Chikungunya viruses based in the nitric oxide release under S-nitrosylation reaction with cysteine viral.

A fluorogenic nitric oxide donor induced by yellow LED light for cells proliferation inhibition and imaging.

Nitric oxide (NO), as a vital cellular signalling molecule in physiological processes, has been found to play an important role in various biological functions. In this study, we rationally designed three NO donors by tethering nitrobenzene derivatives to three fluorescent chromophores. NX-NO was found to release NO and exhibit a high fluorescence turn-on signal ratio upon exposure to LED yellow light. Additionally, it had excellent photo-stability and good inhibitory activity against cancer cell proliferation, and was successfully applied to cell imaging. Moreover, we detected the release of NO and fluorescence response in the blood of a mouse, suggesting its potential therapeutic application in living organisms.

A coumarin-furoxan hybrid as novel nitric oxide donor induced cell apoptosis and ferroptosis in NSCLC by promoting S-nitrosylation of STAT3 and negative regulation of JAK2-STAT3 pathway.

Non-small cell lung cancer (NSCLC) still lacks effective treatment because of its extensive mutation diversity and frequent drug resistance. Therefore, it is urgent to develop new therapeutic strategies for NSCLC. In this study, we evaluated the inhibitory effect of a new coumarin-furoxan hybrid compound 9, a nitric oxide (NO) donor drug, on NSCLC proliferation and its mechanism. Our results show that compound 9 can inhibit the growth of four NSCLC cell lines and H1975 xenograft model in a dose-dependent manner. Compound 9 effectively releases high concentrations of NO within the mitochondria, leading to cellular oxidative stress, mitochondrial dysfunction, and apoptosis. Moreover, compound 9 inhibits JAK2/STAT3 protein phosphorylation and induces S-nitrosylation modification of STAT3, ultimately resulting in endogenous apoptosis in NSCLC. Additionally, compound 9 significantly induces NSCLC ferroptosis by depleting intracellular GSH, elevating MDA levels, inhibiting SLC7A11/GSH protein expression, and negatively regulating the JAK2/STAT3 pathway. In summary, this study elucidates the inhibitory effects of compound 9 on NSCLC proliferation and provides insights into the underlying mechanisms, offering new possibilities for NSCLC treatment strategies.

Liver-targeted nanoparticles delivering nitric oxide reduce portal hypertension in cirrhotic rats.

Nitric oxide (NO) is a small vasodilator playing a key role in the pathogenesis of portal hypertension. Here, we assessed the potential therapeutic effect of a NO donor targeted to the liver by poly(beta-amino ester) nanoparticles (pBAE NPs) in experimental cirrhosis. Retinol-functionalized NO donor pBAE NPs (Ret pBAE NPs) were synthetized with the aim of actively targeting the liver. Administration of Ret pBAE NPs resulted in uptake and transfection by the liver and spleen. NPs were not found in other organs or the systemic circulation. Treatment with NO donor Ret pBAE NPs (30 mg/ kg body weight) significantly decreased aspartate aminotransferase, lactate dehydrogenase and portal pressure (9.75 ± 0.64 mmHg) compared to control NPs (13.4 ± 0.53 mmHg) in cirrhotic rats. There were no effects on mean arterial pressure and cardiac output. Liver-targeted NO donor NPs reduced collagen fibers and steatosis, activation of hepatic stellate cells and mRNA expression of profibrogenic and proinflammatory genes. Finally, Ret pBAE NPs displayed efficient transfection in human liver slices. Overall, liver-specific NO donor NPs effectively target the liver and mitigated inflammation and portal hypertension in cirrhotic rats. The use of Ret pBAE may prove to be an effective therapeutic strategy to treat advanced liver disease.

New 1,2,3-triazole/1,2,4-triazole hybrids linked to oxime moiety as nitric oxide donor selective COX-2, aromatase, B-RAFV600E and EGFR inhibitors celecoxib analogs: design, synthesis, anti-inflammatory/anti-proliferative activities, apoptosis and molecular modeling study.

A new series of bis-triazole 19a-l was synthesised for the purpose of being hybrid molecules with both anti-inflammatory and anti-cancer activities and assessed for cell cycle arrest, NO release. Compounds 19c, 19f, 19h, 19 l exhibited COX-2 selectivity indexes in the range of 18.48 to 49.38 compared to celecoxib S.I. = 21.10), inhibit MCF-7 with IC50 = 9-16 µM compared to tamoxifen (IC50 = 27.9 µM). and showed good inhibitory activity against HEP-3B with IC50 = 4.5-14 µM compared to sorafenib (IC50 = 3.5 µM) (HEP-3B). Moreover, derivatives 19e, 19j, 19k, 19 l inhibit HCT-116 with IC50 = 5.3-13.7 µM compared to 5-FU with IC50 = 4.8 µM (HCT-116). Compounds 19c, 19f, 19h, 19 l showed excellent inhibitory activity against A549 with IC50 = 3-4.5 µM compared to 5-FU with IC50 = 6 µM (A549). Compounds 19c, 19f, 19h, 19 l inhibit aromatase (IC50 of 22.40, 23.20, 22.70, 30.30 µM), EGFR (IC50 of 0.112, 0.205, 0.169 and 0.066 µM) and B-RAFV600E (IC50 of 0.09, 0.06, 0.07 and 0.05 µM).

Discovery and bioassay of disubstituted ß-elemene-NO donor conjugates: synergistic enhancement in the treatment of leukemia.

Natural products are essential sources of antitumor drugs. One such molecule, ß-elemene, is a potent antitumor compound extracted from Curcuma wenyujin. In the present investigation, a series of novel 13,14-disubstituted nitric oxide (NO)-donor ß-elemene derivatives were designed, with ß-elemene as the foundational compound, and subsequently synthesized to evaluate their therapeutic potential against leukemia. Notably, the derivative labeled as compound 13d demonstrated a potent anti-proliferative activity against the K562 cell line, with a high NO release. In vivo studies indicated that compound 13d could effectively inhibit tumor growth, exhibiting no discernible toxic manifestations. Specifically, a significant tumor growth inhibition rate of 62.9% was observed in the K562 xenograft tumor mouse model. The accumulated data propound the potential therapeutic application of compound 13d in the management of leukemia.

Synergic Action of Systemic Risedronate and Local Rutherpy in Peri-implantar Repair of Ovariectomized Rats: Biomechanical and Molecular Analysis.

Postmenopausal osteoporosis and poor dietary habits can lead to overweightness and obesity. Bisphosphonates are the first-line treatment for osteoporosis. However, some studies show that they may increase the risk of osteonecrosis of the jaw. Considering the antimicrobial, angiogenic and vasodilatory potential of nitric oxide, this study aims to evaluate the local activity of this substance during the placement of surface-treated implants. Seventy-two Wistar rats were divided into three groups: SHAM (SHAM surgery), OVX + HD (ovariectomy + cafeteria diet), and OVX + HD + RIS (ovariectomy + cafeteria diet + sodium risedronate treatment), which were further subdivided according to the surface treatment of the future implant: CONV (conventional), TE10, or TE100 (TERPY at 10 or 100 µM concentration); n = 8 per subgroup. The animals underwent surgery for implant installation in the proximal tibia metaphysis and were euthanized after 28 days. Data obtained from removal torque and RT-PCR (OPG, RANKL, ALP, IBSP and VEGF expression) were subjected to statistical analysis at 5% significance level. For biomechanical analysis, TE10 produced better results in the OVX + HD group (7.4 N/cm, SD = 0.6819). Molecular analysis showed: (1) significant increase in OPG gene expression in OVX groups with TE10; (2) decreased RANKL expression in OVX + HD + RIS compared to OVX + HD; (3) significantly increased expressions of IBSP and VEGF for OVX + HD + RIS TE10. At its lowest concentration, TERPY has the potential to improve peri-implant conditions.

Implications of ZnO Nanoparticles and S-Nitrosoglutathione on Nitric Oxide, Reactive Oxidative Species, Photosynthetic Pigments, and Ionomic Profile in Rice.

Zinc is an important nutrient for several plants and humans. Nitric oxide (NO) is a free radical that is important to biological processes that mediate the growth and mitigation of biotic and abiotic stresses in plants. The present study investigated the enzymatic and photosynthetic profile and the accumulation of macro- and microelements in rice plants (Oryza sativa L.) that received foliar treatments of zinc oxide nanoparticles (ZnO NPs), nitric oxide donor (GSNO), and the association of both (GSNO-ZnO NPs). Zinc concentration in rice husks increased by 66% and 68% in plants treated with ZnO NPs and GSNO-ZnO NPs, respectively. The GSNO treatment caused an increase of 25% in the Fe concentration in the rice grains. Only a small disturbance of the antioxidant system was observed, with increases in H2O2, S-NO, and NO2-, mainly in the group treated with GSNO-ZnO NPs; however, the disturbance did not affect the yield, the growth, or vital processes, such as as photosynthetic pigments production. There was an increase in chlorophyll B of 290% and an increase in chlorophyll A of 187% when ZnO NPs was applied. GSNO-ZnO NPs increased chlorophyll B by 345% and chlorophyll A by 345%, indicating that the treatments GSNO, ZnO NPs, and GSNO-ZnO NPs reduced possible oxidative stress and helped as protective treatments.

A Novel Dual-Function Redox Modulator Relieves Oxidative Stress and Anti-Angiogenic Response in Placental Villus Explant Exposed to Hypoxia-Relevance for Preeclampsia Therapy.

BACKGROUND: Preeclampsia (PE) is a severe, life-threatening complication during pregnancy (~5-7%), and no causative treatment is available. Early aberrant spiral artery remodeling is associated with placental stress and the release of oxygen radicals and other reactive oxygen species (ROS) in the placenta. This precedes the production of anti-angiogenic factors, which ultimately leads to endothelial and trophoblast damage and the key features of PE. We tested whether a novel dual-function redox modulator-AKT-1005-can effectively reduce placental oxidative stress and alleviate PE symptoms in vitro. METHOD: Isolated human villous explants were exposed to hypoxia and assessed to determine whether improving cell-redox function with AKT-1005 diminished ROS production, mitochondrial stress, production of the transcription factor HIF1A, and downstream anti-angiogenic responses (i.e., sFLT1, sEng production). MitoTEMPO was used as a reference antioxidant. RESULTS: In our villous explant assays, pretreatment with AKT-1005 reduced mitochondrial-derived ROS production, reduced HIF-1A, sFLT1, and sEng protein expression, while increasing VEGF in hypoxia-exposed villous trophoblast cells, with better efficiency than MitoTEMPO. In addition, AKT-1005 improved mitochondrial electron chain enzyme activity in the stressed explant culture. CONCLUSIONS: The redox modulator AKT-1005 has the potential to intervene with oxidative stress and can be efficacious for PE therapy. Future studies are underway to assess the in vivo efficacy of HMP.

Two-in-One Polymeric NO-Donor Prodrugs Mediate Precision and Synergistic Prostate Cancer Treatment.

Chemotherapy predominates in clinical treatment of prostate cancer (PCa), while irreversible resistance to chemotherapeutics and severe side effects hinder the therapeutic efficacy, especially in castration-resistant PCa (CRPC). Herein, a bombesin (BBN)-decorated two-in-one prodrug (T-NO/E2-PMs) incorporating a polymeric nitric oxide (NO) donor and acetal-linked 17ß-estradiol (E2) in one backbone is developed, aiming to inhibit androgen receptor (AR) expression, reprogram the tumor microenvironment of CRPC, and enhance estradiol-mediated hypoxic CRPC therapy. Following efficient internalization mediated by BBN, T-NO/E2-PMs releases estradiol and NO in response to the unique intracellular environments. Both in vitro and in vivo studies demonstrate that the T-NO/E2-PMs nano-prodrug along with NO release potently downregulates AR levels to reverse CRPC and further enhances the chemo-sensitization of estradiol to PCa PC-3 cell apoptosis and the inhibition of metastasis. Collectively, this two-in-one nano-prodrug strategy offers a promising platform for construction of advanced nanomedicine to boost the therapeutic efficacy.

GTN Enhances Antitumor Effects of Doxorubicin in TNBC by Targeting the Immunosuppressive Activity of PMN-MDSC.

(1) Background: Immunosuppression is a key barrier to effective anti-cancer therapies, particularly in triple-negative breast cancer (TNBC), an aggressive and difficult to treat form of breast cancer. We investigated here whether the combination of doxorubicin, a standard chemotherapy in TNBC with glyceryltrinitrate (GTN), a nitric oxide (NO) donor, could overcome chemotherapy resistance and highlight the mechanisms involved in a mouse model of TNBC. (2) Methods: Balb/C-bearing subcutaneous 4T1 (TNBC) tumors were treated with doxorubicin (8 mg/Kg) and GTN (5 mg/kg) and monitored for tumor growth and tumor-infiltrating immune cells. The effect of treatments on MDSCs reprogramming was investigated ex vivo and in vitro. (3) Results: GTN improved the anti-tumor efficacy of doxorubicin in TNBC tumors. This combination increases the intra-tumor recruitment and activation of CD8+ lymphocytes and dampens the immunosuppressive function of PMN-MDSCs PD-L1low. Mechanistically, in PMN-MDSC, the doxorubicin/GTN combination reduced STAT5 phosphorylation, while GTN +/- doxorubicin induced a ROS-dependent cleavage of STAT5 associated with a decrease in FATP2. (4) Conclusion: We have identified a new combination enhancing the immune-mediated anticancer therapy in a TNBC mouse model through the reprograming of PMN-MDSCs towards a less immunosuppressive phenotype. These findings prompt the testing of GTN combined with chemotherapies as an adjuvant in TNBC patients experiencing treatment failure.

Recent advances in diverse nanosystems for nitric oxide delivery in cancer therapy.

Gas therapy has been proven to be a promising and advantageous treatment option for cancers. Studies have shown that nitric oxide (NO) is one of the smallest structurally significant gas molecules with great potential to suppress cancer. However, there is controversy and concern about its use as it exhibits the opposite physiological effects based on its levels in the tumor. Therefore, the anti-cancer mechanism of NO is the key to cancer treatment, and rationally designed NO delivery systems are crucial to the success of NO biomedical applications. This review summarizes the endogenous production of NO, its physiological mechanisms of action, the application of NO in cancer treatment, and nano-delivery systems for delivering NO donors. Moreover, it briefly reviews challenges in delivering NO from different nanoparticles and the issues associated with its combination treatment strategies. The advantages and challenges of various NO delivery platforms are recapitulated for possible transformation into clinical applications.

Intranasal administration of sodium nitroprusside augments antigen-specific mucosal and systemic antibody production in mice.

The coronavirus disease 2019, i.e., the COVID-19 pandemic, caused by a highly virulent and transmissible pathogen, has profoundly impacted global society. One approach to combat infectious diseases caused by pathogenic microbes is using mucosal vaccines, which can induce antigen-specific immune responses at both the mucosal and systemic sites. Despite its potential, the clinical implementation of mucosal vaccination is hampered by the lack of safe and effective mucosal adjuvants. Therefore, developing safe and effective mucosal adjuvants is essential for the fight against infectious diseases and the widespread clinical use of mucosal vaccines. In this study, we demonstrated the potent mucosal adjuvant effects of intranasal administration of sodium nitroprusside (SNP), a known nitric oxide (NO) donor, in mice. The results showed that intranasal administration of ovalbumin (OVA) in combination with SNP induced the production of OVA-specific immunoglobulin A in the mucosa and increased serum immunoglobulin G1 levels, indicating a T helper-2 (Th2)-type immune response. However, an analog of SNP, sodium ferrocyanide, which does not generate NO, failed to show any adjuvant effects, suggesting the critical role of NO generation in activating an immune response. In addition, SNPs facilitated the delivery of antigens to the lamina propria, where antigen-presenting cells are located, when co-administered with antigens, and also transiently elicited the expression of interleukin-6, interleukin-1ß, granulocyte colony-stimulating factor, C-X-C motif chemokine ligand 1, and C-X-C motif chemokine ligand 2 in nasal tissue. These result suggest that SNP is a dual-functional formulation with antigen delivery capabilities to the lamina propria and the capacity to activate innate immunity. In summary, these results demonstrate the ability of SNP to induce immune responses via an antigen-specific Th2-type response, making it a promising candidate for further development as a mucosal vaccine formulation against infectious diseases.

Design, synthesis, modeling studies and biological evaluation of pyrazole derivatives linked to oxime and nitrate moieties as nitric oxide donor selective COX-2 and aromatase inhibitors with dual anti-inflammatory and anti-neoplastic activities.

Two new series of pyrazole derivatives 10a-f and 11a-f with selective COX-2 inhibition pharmacophore and oxime/nitrate moieties as NO donor moiety were designed, synthesized and tested for anti-inflammatory, cytotoxic activities and NO release. Compounds 10c, 11a, 11e were more selective for COX-2 isozyme (S.I. = 25.95, 22.52 and 21.54 respectively) in comparison to celecoxib (S.I. = 21.41). Regarding anti-cancer activity, all synthesized compounds were screened by the National Cancer Institute (NCI), Bethesda, USA for anticancer activity against 60 human cancer cell lines representing the following cancer types: leukemia, non-small cell lung, colon, CNS, melanoma, ovarian, renal, prostate, and breast cancers. Compounds 10c, 11a, 11e were found to be the most potent inhibitors on breast, ovarian and melanoma cell lines (MCF-7, IGROV1 and SK-MEL-5), compound 11a causing 79 % inhibition in case of MCF-7, 78.80 % inhibition in case of SK-MEL-5 and unexpected cell growth -26.22 % inhibition in case of IGROV1 (IC50 = 3.12, 4.28, 4.13 µM respectively). On the other hand, compounds 10c and 11e showed lower inhibition on the same cell lines with IC50 = 3.58, 4.58, 4.28 µM respectively for 10c, IC50 = 3.43, 4.73, 4.43 µM respectively for 11e. Furthermore, DNA-flow cytometric analysis showed that compound 11a induces cell cycle arrest at G2/M phase leading to cell proliferation inhibition and apoptosis. Additionally, these derivatives examined against F180 fibroblasts to investigate their selectivity indexes. The pyrazole derivative with internal oxime 11a was the most potent compound against most used cell lines especially MCF-7, IGROV1 and SK-MEL-5 (IC50 = 3.12, 4.28, 4.13 µM respectively) with 4.82-fold selectivity towards MCF-7 than F180 fibroblasts. Moreover, oxime derivative 11a showed potent aromatase inhibitory activity (IC50 16.50 µM) when compared with reference compound letrozole (IC50 15.60 µM). All compounds 10a-f and 11a-f released NO in a slow rate (0.73-3.88 %) and the six derivatives 10c, 10e, 11a, 11b, 11c and 11e were the highest NO releasers (3.88, 2.15, 3.27, 2.27, 2.55 and 3.74 % respectively). Herein structure based and ligand based studies were implemented to under stand and evaluate the compounds activity for further in vivo and preclinical studies. Docking mode of final designed compounds with celecoxib (ID: 3LN1) represented that their triazole ring adopted as the core aryl in Y shaped structure. Regarding aromatase enzyme inhibition, docking was carried out with ID: 1 M17. The internal oxime series was more active as anticancer because of their ability to form extra HBs with receptor cleft.

Renal replacement therapy removes a large number of nitric oxide donors responsible for the nitrate-nitrite-nitric oxide pathway.

BACKGROUNDS: Nitric oxide has a broad-spectrum antibacterial property promising as a new therapeutic agent for severe acute respiratory syndrome coronavirus-2 because nitric oxide donor (such as S-nitroso-N-acetylpenicillamine) reduces the replication of coronavirus-2. Patients with coronavirus disease 2019 undergoing dialysis generally have a higher mortality rate than the general population. Although the higher mortality rate in these patients may be related to their advanced age, it has been suggested that plasma nitrite and nitrate levels (products of nitric oxide metabolism) are significantly decreased after hemodialysis which may compromise the nitrate-nitrite-nitric oxide pathway and impair nitric oxide homeostasis. It results in increased cardiovascular mortality in patients undergoing dialysis. However, the profile of nitric oxide-producing substances is poorly understood during renal replacement therapy. METHODS: We simulated continuous hemodialysis and hemodiafiltration to measure the amount of nitric oxide (nitric oxide-producing substance) clearance in vitro. RESULTS: The results demonstrated increased nitric oxide clearance and higher clearance than creatinine (molecular weight: 113) and vitamin B12 (molecular weight: 1355) using highly efficient renal replacement therapy modes. CONCLUSION: The high nitric oxide clearance may have partly contributed to the high cardiovascular and coronavirus-2 mortality risk in patients on dialysis.

Repurposing nitric oxide donating drugs in cancer therapy through immune modulation.

BACKGROUND: Nitric oxide-releasing drugs are used for cardiovascular diseases; however, their effects on the tumor immune microenvironment are less clear. Therefore, this study explored the impact of nitric oxide donors on tumor progression in immune-competent mice. METHODS: The effects of three different nitric oxide-releasing compounds (SNAP, SNP, and ISMN) on tumor growth were studied in tumor-bearing mouse models. Three mouse tumor models were used: B16F1 melanoma and LL2 lung carcinoma in C57BL/6 mice, CT26 colon cancer in BALB/c mice, and LL2 lung carcinoma in NOD/SCID mice. After nitric oxide treatment, splenic cytokines and lymphocytes were analyzed by cytokine array and flow cytometry, and tumor-infiltrating lymphocytes in the TME were analyzed using flow cytometry and single-cell RNA sequencing. RESULTS: Low doses of three exogenous nitric oxide donors inhibited tumor growth in two immunocompetent mouse models but not in NOD/SCID immunodeficient mice. Low-dose nitric oxide donors increase the levels of splenic cytokines IFN-γ and TNF-α but decrease the levels of cytokines IL-6 and IL-10, suggesting an alteration in Th2 cells. Nitric oxide donors increased the number of CD8+ T cells with activation gene signatures, as indicated by single-cell RNA sequencing. Flow cytometry analysis confirmed an increase in infiltrating CD8+ T cells and dendritic cells. The antitumor effect of nitric oxide donors was abolished by depletion of CD8+ T cells, indicating the requirement for CD8+ T cells. Tumor inhibition correlated with a decrease in a subtype of protumor macrophages and an increase in a subset of Arg1-positive macrophages expressing antitumor gene signatures. The increase in this subset of macrophages was confirmed by flow cytometry analysis. Finally, the combination of low-dose nitric oxide donor and cisplatin induced an additive cancer therapeutic effect in two immunocompetent animal models. The enhanced therapeutic effect was accompanied by an increase in the cells expressing the gene signature of NK cell. CONCLUSIONS: Low concentrations of exogenous nitric oxide donors inhibit tumor growth in vivo by regulating T cells and macrophages. CD8+ T cells are essential for antitumor effects. In addition, low-dose nitric oxide donors may be combined with chemotherapeutic drugs in cancer therapy in the future.

Targeted delivery of Nitric Oxide triggered by α-Glucosidase to Ameliorate NSAIDs-induced Enteropathy.

Nonsteroidal anti-inflammatory drugs (NSAIDs) increase risks of severe small intestinal injuries. Development of effective therapeutic strategies to overcome this issue remains challenging. Nitric oxide (NO) as a gaseous mediator plays a protective role in small intestinal injuries. However, small intestine-specific delivery systems for NO have not been reported yet. In this study, we reported a small intestine-targeted polymeric NO donor (CS-NO) which was synthesized by covalent grafting of α-glucosidase-activated NO donor onto chitosan. In vitro and in vivo experiments demonstrated that CS-NO could be activated by intestinal α-glucosidase to release NO in the small intestine. Pre-treatment of mice with CS-NO significantly alleviated small intestinal damage induced by indomethacin, as demonstrated by down-regulation of the levels of pro-inflammatory cytokines and chemokines CXCL1/KC. Moreover, CS-NO also attenuated indomethacin-induced gut barrier dysfunction as evidenced by up-regulation of the levels of tight junction proteins and restoration of the levels of goblet cells and MUC2 production. Meanwhile, CS-NO effectively restored the defense function of Paneth cells against pathogens in small intestine. Our present study paves the way to develop NO-based therapeutic strategy for NSAIDs-induced small intestinal injuries.

Photo-controllable burst generation of peroxynitrite based on synergistic interactions of polymeric nitric oxide donors and IR780 for enhancing broad-spectrum antibacterial therapy.

The newly attractive peroxynitrite (ONOO-) therapy can prominently enhance antibacterial therapeutic efficacy. However, it is a great challenge but urgently needed to generate ONOO- with adjustable release rate and dosage in order to satisfy personalized treatments for different disease types and severities. Herein, PSNO@IR780 nanoparticles are fabricated via co-assembly of an amphiphilic PEG-b-PAASNO block copolymer grafted with abundant nitric oxide (NO) donor units and IR780 as a photothermal and photodynamic agent. Photo-controllable burst generation of ONOO- from PSNO@IR780 nanoparticles could be realized based on synergistic reactions of rapid NO release induced by increased local temperature and efficiently produced superoxide anion radical (O2•-) from IR780. The maximum ONOO- release dosage is up to 6.73 ± 0.07 µM and release rate is up to 98.1 ± 1.38 nM/s. Furthermore, the ONOO- release behavior can be precisely manipulated by varying sample concentrations, irradiated durations, output power densities, and laser switches, respectively. Ultra-efficiently generated ONOO- from biocompatible PSNO@IR780 nanoparticles significantly elevated broad spectrum antibacterial efficiency through damaging bacterial membranes. Thus, PSNO@IR780 nanoparticles may present a new insight into preparation of burst and controllable generating ONOO- materials, and provide new opportunities for antibacterial therapy. STATEMENT OF SIGNIFICANCE: 1. Polymeric NO donor (PEG-b-PAASNO) grafted with abundant NO donor units was synthesized. 2. PSNO@IR780 nanoparticles were prepared by co-assembly of IR780 and amphiphilic PEG-b-PAASNOpolymer. 3. The maximum ONOO- release dosage from PSNO@IR780 nanoparticles was 6.73 ± 0.08 µM. 4. The fastest ONOO- release rate from PSNO@IR780 nanoparticles was 98.1 ± 1.4 nM/s. 5. Ultra-efficiently generated ONOO- significantly elevated antibacterial efficiency via damaging bac-terial membranes.