iNOS Promotes the Development of Osteosarcoma via Wnt/β-Catenin Pathway

Inducible nitric oxide synthase (iNOS), accompanied with protumor and antitumor activity, has been studied in multiple cancers. However, the role of iNOS expression in osteosarcoma (OS) is far from being fully understood. In present work, iNOS levels were detected in OS tissues and cell lines. Colony formation assay, Transwell assay, and fow cytometer were used to assess proliferation, migration, invasion, and apoptosis abilities in vitro after iNOS inhibition. Western blotting determined the expressions of iNOS, MMP2, MMP9, C-MYC, Ki67, PCNA, and β-catenin. Mice transfected with OS cells were to evaluate tumor formation. IHC assay was to evaluate the expressions of iNOS and β-catenin in mice. The results showed that iNOS was upregulated in both OS tissues and cells compared with that in matched normal tissues or cells. And we found that proliferation, migration, and invasion numbers of OS cells were decreased, and apoptosis numbers of OS cells were increased after iNOS inhibition. MMP2, MMP9, C-MYC, Ki67, and PCNA levels were also reduced in OS cells treated with iNOS inhibition. Else, iNOS inhibition would suppress β-catenin expression in OS cells to regulate MMP2, MMP9, C-MYC, Ki67, and PCNA expressions. In addition, tumor formation, iNOS expression, and β-catenin expression were inhibited in mice transplanted with iNOS knockout OS cells. These results indicated that iNOS might be a potential therapeutic target for OS.

Dexamethasone increased the survival rate in Plasmodium berghei-infected mice

The present study aimed to evaluate the effects of dexamethasone on the redox status, parasitemia evolution, and survival rate of Plasmodium berghei-infected mice. Two-hundred and twenty-five mice were infected with Plasmodium berghei and subjected to stimulation or inhibition of NO synthesis. The stimulation of NO synthesis was performed through the administration of L-arginine, while its inhibition was made by the administration of dexamethasone. Inducible NO synthase (iNOS) inhibition by dexamethasone promoted an increase in the survival rate of P. berghei-infected mice, and the data suggested the participation of oxidative stress in the brain as a result of plasmodial infection, as well as the inhibition of brain NO synthesis, which promoted the survival rate of almost 90% of the animals until the 15th day of infection, with possible direct interference of ischemia and reperfusion syndrome, as seen by increased levels of uric acid. Inhibition of brain iNOS by dexamethasone caused a decrease in parasitemia and increased the survival rate of infected animals, suggesting that NO synthesis may stimulate a series of compensatory redox effects that, if overstimulated, may be responsible for the onset of severe forms of malaria.

A Review on Newer Ocular Drug Delivery Systems with an Emphasis on Glaucoma

Glaucoma is an irreversible condition resulting from the increase in intraocular pressure (IOP); which leads to permanent loss of vision with the destruction of retinal ganglion cells (RGCs). The IOP elevations are controlled in normal by the physiological flow of aqueous humour. A population with age above 40 is more susceptible to glaucoma. Other factors like gender, genetics, race etc. plays major roles in the development of the disease. Current treatment methods available for the disease includes drugs come under the classes of beta receptor blockers, carbonic anhydrase inhibitors, cholinergic agonists, prostaglandins etc. N-methyl-D-aspartate (NMDA) antagonists, inducible nitric oxide synthase (iNOS) inhibition, cytoskeletal agents, Rho-kinase inhibitors etc are few novel targets sites which are in research focus for the treatment of the disease. Developments in nanomedicine are also being evaluated for their potential in treating the growing glaucomatous population. Nanosystems are suggested to avoid the difficulties in tackling the various ocular barriers to a limit, help to decrease the instillation frequency of topical medication and can provide drug delivery in a sustained or controlled manner. This review focuses on the current and emerging treatment methods for glaucoma along with some of the nanoformulations for ocular drug delivery.

Calcium-dependent cytosolic phospholipase A2 activation is implicated in neuroinflammation and oxidative stress associated with ApoE4

Background Apolipoprotein E4 (APOE4) is associated with a greater response to neuroinflammation and risk of developing late-onset Alzheimer disease (AD), but the mechanisms for this association are not clear. Activation of calcium-dependent cytosolic phospholipase A2 (cPLA2) is involved in inflammatory signaling and is elevated within plaques of the AD brain. The relation between APOE4 genotype and cPLA2 activity is not known. Methods Mouse primary astrocytes, mouse and human brain samples differing by APOE genotypes were collected for measuring cPLA2 expression, phosphorylation and activity in relation to measures of inflammation and oxidative stress. Results Greater cPLA2 phosphorylation and activity were identified in ApoE4 compared to ApoE3 in primary astrocytes and brains of ApoE-targeted replacement (ApoE-TR) mice. These differences were also demonstrated in brain homogenates from the inferior frontal cortex from AD patients carrying APOE3/4 compared to APOE3/3. Higher cPLA2 activation with APOE4 was associated with greater activation of the MAPK p38 pathway, as well as with higher levels of leukotriene B4 (LTB4), reactive oxygen species (ROS) and inducible nitric oxide synthase (iNOS). Inhibition of cPLA2 reduced LTB4, ROS and iNOS levels in ApoE4 primary astrocytes to those of ApoE3 astrocytes. Conclusions Our findings implicate greater activation of cPLA2 signaling system with APOE4, that could represent a potential drug target for mitigating the increased neuroinflammation with APOE4 and AD.

Simultaneous inhibition of peripheral CB1R and iNOS mitigates obesity-related dyslipidemia through distinct mechanisms

Diabetic dyslipidemia (DD), characterized by increased plasma triglycerides (TGs) and decreased high-density lipoprotein cholesterol (HDL) levels, is a major factor contributing to non-alcoholic steatohepatitis (NASH) and cardiovascular risk in type-2 diabetes. Activation of both the cannabinoid-1 receptor (CB1R) and inducible nitric oxide synthase (iNOS) are associated with NASH progression. Here, we tested whether dual-targeting inhibition of hepatic CB1R and iNOS improves DD in diet-induced obese (DIO) mice. DIO mice were treated for 14 days with <i>(S)</i>-MRI-1867, a peripherally-restricted hybrid inhibitor of CB1R and iNOS. <a><i>(R)</i>-MRI-1867, the CB1R-inactive stereoisomer which retains iNOS inhibitory activity and JD-5037, a peripherally-restricted CB1R antagonist</a> were used to assess the relative contribution of the two targets to the effects of <i>(S)</i>-MRI-1867. <i>(S)</i>-MRI-1867 reduced hepatic steatosis, the rate of hepatic VLDL secretion, upregulated hepatic LDLR expression and reduced the circulating levels of the proprotein convertase subtilisin/kexin type 9 (PCSK9). The decrease in VLDL secretion could be attributed to CB1R blockade while the reduction of PCSK9 levels and the related increase in LDLR resulted from iNOS inhibition via a mTORC1-dependent mechanism. In conclusion, this approach based on the concomitant inhibition of CB1R and iNOS represents a promising therapeutic strategy for the treatment of dyslipidemia.

Simultaneous inhibition of peripheral CB1R and iNOS mitigates obesity-related dyslipidemia through distinct mechanisms

Diabetic dyslipidemia (DD), characterized by increased plasma triglycerides (TGs) and decreased high-density lipoprotein cholesterol (HDL) levels, is a major factor contributing to non-alcoholic steatohepatitis (NASH) and cardiovascular risk in type-2 diabetes. Activation of both the cannabinoid-1 receptor (CB1R) and inducible nitric oxide synthase (iNOS) are associated with NASH progression. Here, we tested whether dual-targeting inhibition of hepatic CB1R and iNOS improves DD in diet-induced obese (DIO) mice. DIO mice were treated for 14 days with <i>(S)</i>-MRI-1867, a peripherally-restricted hybrid inhibitor of CB1R and iNOS. <a><i>(R)</i>-MRI-1867, the CB1R-inactive stereoisomer which retains iNOS inhibitory activity and JD-5037, a peripherally-restricted CB1R antagonist</a> were used to assess the relative contribution of the two targets to the effects of <i>(S)</i>-MRI-1867. <i>(S)</i>-MRI-1867 reduced hepatic steatosis, the rate of hepatic VLDL secretion, upregulated hepatic LDLR expression and reduced the circulating levels of the proprotein convertase subtilisin/kexin type 9 (PCSK9). The decrease in VLDL secretion could be attributed to CB1R blockade while the reduction of PCSK9 levels and the related increase in LDLR resulted from iNOS inhibition via a mTORC1-dependent mechanism. In conclusion, this approach based on the concomitant inhibition of CB1R and iNOS represents a promising therapeutic strategy for the treatment of dyslipidemia.

Novel Coupled Molecules from Active Structural Motifs of Synthetic and Natural Origin as Immunosuppressants

Introduction: Nitric oxide (NO) is an important mediator in the pathogenesis and control of immune system-related disorders and its levels are modulated by inducible NO synthase (iNOS). Oxidative stress is another pathological indication in majority of autoimmune disorders. The present study aims at the development of coupled molecules via selection of pharmacophores for both immunomodulatory and antioxidant activities through iNOS inhibition. Methods: Variedly substituted coumarin moieties are coupled with naturally occurring phenols through an amide linkage and were predicted for activities using computer-based program PASS. The compounds predicted to have dual activities were synthesized. Docking studies were carried out against iNOS (PDB 1R35) and compounds having good docking score were evaluated for immunomodulatory and antioxidant activities. Results: The synthesized compounds were found to be pure and were obtained in good yields. Compounds with maximum docking score (YR1a, YR2e, YR2c and YR4e) were selected for evaluation by in vitro models. Compounds YR2e and YR2c markedly inhibited the reduction of NBT dye and showed maximum % iNOS inhibition. In DPPH assay, compound YR4e was observed as the most potent antioxidant (EC50 0.33 µM/mL). Based on these studies, compounds YR2e and YR2c were selected for haemagglutination test. Compound YR2e was observed as the most active immunosuppressant with maximal inhibitory ability of iNOS and NBT reduction and lower HAT value of 3.5. Conclusion: Compound YR2e can be utilized as a pharmacological agent in the prevention or treatment of immunomodulatory diseases such as tumors, rheumatoid arthritis, ulcerative colitis, organ transplant and other autoimmune disorders.

Search for Potential Inducible Nitric Oxide Synthase Inhibitors with Favorable ADMET Profiles for the Therapy of Helicobacter pylori Infections

Background: Helicobacter pylori is a gram-negative bacterium related to chronic gastritis, peptic ulcer and gastric carcinoma. During its infection process, promotes excessive inflammatory response, increasing the release of reactive species and inducing the production of pro-inflammatory mediators. Inducible Nitric Oxide Synthase (iNOS) plays a crucial role in the gastric carcinogenesis process and a key mediator of inflammation and host defense systems, which is expressed in macrophages induced by inflammatory stimuli. In chronic diseases such as Helicobacter pylori infections, the overproduction of NO due to the prolonged induction of iNOS is of major concern. Objective: In this sense, the search for potential iNOS inhibitors is a valuable strategy in the overall process of Helicobacter pylori pathogeny. Method: In silico techniques were applied in the search of interesting compounds against Inducible Nitric Oxide Synthase enzyme in a chemical space of natural products and derivatives from the Analyticon Discovery databases. Results: The five compounds with the best iNOS inhibition profile were selected for activity and toxicity predictions. Compound 9 (CAS 88198-99-6) displayed significant potential for iNOS inhibition, forming hydrogen bonds with residues from the active site and an ionic interaction with heme. This compound also displayed good bioavailability and absence of toxicity/or from its probable metabolites. Conclusion: The top-ranked compounds from the virtual screening workflow show promising results regarding the iNOS inhibition profile. The results evidenced the importance of the ionic bonding during docking selection, playing a crucial role in binding and positioning during ligand-target selection for iNOS.

Differences in cNOS/iNOS Activity during Resistance to Trypanosoma cruzi Infection in 5-Lipoxygenase Knockout Mice

Infection with the protozoan Trypanosoma cruzi causes Chagas disease and consequently leads to severe inflammatory heart condition; however, the mechanisms driving this inflammatory response have not been completely elucidated. Nitric oxide (NO) is a key mediator of parasite killing in T. cruzi-infected mice, and previous studies have suggested that leukotrienes (LTs) essentially regulate the NO activity in the heart. We used infected 5-lipoxygenase-deficient mice (5-LO−/−) to explore the participation of nitric oxide synthase isoforms, inducible (iNOS) and constitutive (cNOS), in heart injury, cytokine profile, and oxidative stress during the early stage of T. cruzi infection. Our evidence suggests that the cNOS of the host is involved in the resistance of 5-LO−/− mice during T. cruzi infection. iNOS inhibition generated a remarkable increase in T. cruzi infection in the blood and heart of mice, whereas cNOS inhibition reduced cardiac parasitism (amastigote nests). Furthermore, this inhibition associates with a higher IFN-γ production and lower lipid peroxidation status. These data provide a better understanding about the influence of NO-interfering therapies for the inflammatory response toward T. cruzi infection.