A novel dual NO-donating oxime and c-Jun N-terminal kinase inhibitor protects against cerebral ischemia-reperfusion injury in mice

Evaluation of Nitric Oxide-Donating Properties of 11H-indeno[1,2-b]quinoxalin-11-one Oxime (IQ-1) by Electron Paramagnetic Resonance Spectroscopy

IQ-1 (11H-indeno[1,2-b]quinoxalin-11-one oxime) is a specific c-Jun N-terminal kinase (JNK) inhibitor with anticancer and neuro- and cardioprotective properties. Because aryloxime derivatives undergo cytochrome P450-catalyzed oxidation to nitric oxide (NO) and ketones in liver microsomes, NO formation may be an additional mechanism of IQ-1 pharmacological action. In the present study, electron paramagnetic resonance (EPR) of the Fe2+ complex with diethyldithiocarbamate (DETC) as a spin trap and hemoglobin (Hb) was used to detect NO formation from IQ-1 in the liver and blood of rats, respectively, after IQ-1 intraperitoneal administration (50 mg/kg). Introducing the spin trap and IQ-1 led to signal characteristics of the complex (DETC)2-Fe2+-NO in rat liver. Similarly, the introduction of the spin trap components and IQ-1 resulted in an increase in the Hb-NO signal for both the R- and the T-conformers in blood samples. The density functional theory (DFT) calculations were in accordance with the experimental data and indicated that the NO formation of IQ-1 through the action of superoxide anion radical is thermodynamically favorable. We conclude that the administration of IQ-1 releases NO during its oxidoreductive bioconversion in vivo.

Pharmacokinetics of a New Neuroprotector - Indenoquinoxalinone Derivative after Intravenous Administration in Rabbits and Rats

The specific JNK inhibitor and NO donor 11H-indeno[1,2-b]quinoxalin-11-one oxime (IQ-1) demonstrated pronounced neuroprotective properties in an in vivo model of ischemic stroke in rats. The pharmacokinetic behavior of IQ-1 was studied in two animal species (rats, rabbits) after intravenous administration in a dose of 1 mg/kg. IQ-1 concentrations in venous blood plasma were measured by the liquid chromatography-tandem mass spectrometry method. The pharmacokinetics of IQ-1 was adequately described by the two-compartmental model. The calculated C0 for IQ-1 in rabbit and rat plasma were 2239.83±1229.55 and 1552.50±182.23 ng/ml, respectively. Two animal species are characterized by extensive tissue distribution of IQ-1 (Vss exceeded the total body water in rabbits and rats by 3.6 and 5.6 times, respectively) and high clearance values (88-94% of hepatic blood flow).

Neuroprotective Effects of Tryptanthrin-6-Oxime in a Rat Model of Transient Focal Cerebral Ischemia

The activation of c-Jun N-terminal kinase (JNK) plays an important role in stroke outcomes. Tryptanthrin-6-oxime (TRYP-Ox) is reported to have high affinity for JNK and anti-inflammatory activity and may be of interest as a promising neuroprotective agent. The aim of this study was to investigate the neuroprotective effects of TRYP-Ox in a rat model of transient focal cerebral ischemia (FCI), which involved intraluminal occlusion of the left middle cerebral artery (MCA) for 1 h. Animals in the experimental group were administered intraperitoneal injections of TRYP-Ox 30 min before reperfusion and 23 and 47 h after FCI. Neurological status was assessed 4, 24, and 48 h following FCI onset. Treatment with 5 and 10 mg/kg of TRYP-Ox decreased mean scores of neurological deficits by 35-49 and 46-67% at 24 and 48 h, respectively. At these doses, TRYP-Ox decreased the infarction size by 28-31% at 48 h after FCI. TRYP-Ox (10 mg/kg) reduced the content of interleukin (IL) 1β and tumor necrosis factor (TNF) in the ischemic core area of the MCA region by 33% and 38%, respectively, and attenuated cerebral edema by 11% in the left hemisphere, which was affected by infarction, and by 6% in the right, contralateral hemisphere 24 h after FCI. TRYP-Ox reduced c-Jun phosphorylation in the MCA pool at 1 h after reperfusion. TRYP-Ox was predicted to have high blood-brain barrier permeability using various calculated descriptors and binary classification trees. Indeed, reactive oxidant production was significantly lower in the brain homogenates from rats treated with TRYP-Ox versus that in control animals. Our data suggest that the neuroprotective activity of TRYP-Ox may be due to the ability of this compound to inhibit JNK and exhibit anti-inflammatory and antioxidant activity. Thus, TRYP-Ox may be considered a promising neuroprotective agent that potentially could be used for the development of new treatment strategies in cerebral ischemia.

Experimental and Computational Investigation of the Oxime Bond Stereochemistry in c-Jun N-terminal Kinase 3 Inhibitors 11H-Indeno[1,2-b]quinoxalin-11-one Oxime and Tryptanthrin-6-oxime

11H-Indeno[1,2-b]quinoxalin-11-one oxime (IQ-1) and tryptanthrin-6-oxime are potent c-Jun N-terminal kinase 3 (JNK-3) inhibitors demonstrating neuroprotective, anti-inflammatory and anti-arthritic activity. However, the stereochemical configuration of the oxime carbon-nitrogen double bond (E- or Z-) in these compounds was so far unknown. In this contribution, we report the results of the determination of the double bond configuration in the solid state by single crystal X-ray diffraction and in solution by 1D and 2D NMR techniques and DFT calculations. It was found that both in the solid state and in solution, IQ-1 adopts the E-configuration stabilized by intermolecular hydrogen bonds, in contrast to previously assumed Z-configuration that could be stabilized only by an intramolecular hydrogen bond.

Suppression of Age-Related Macular Degeneration-like Pathology by c-Jun N-Terminal Kinase Inhibitor IQ-1S

Age-related macular degeneration (AMD) is the leading cause of irreversible visual impairment worldwide. The development of AMD is associated with inflammation, oxidative stress, and progressive proteostasis imbalance, in the regulation of which c-Jun N-terminal kinases (JNK) play a crucial role. JNK inhibition is discussed as an alternative way for prevention and treatment of AMD and other neurodegenerative diseases. Here we assess the retinoprotective potential of the recently synthesized JNK inhibitor 11H-indeno[1,2-b]quinoxalin-11-one oxime sodium salt (IQ-1S) using senescence-accelerated OXYS rats as a model of AMD. The treatment with IQ-1S (50 mg/kg body weight intragastric) during the period of active disease development (from 4.5 to 6 months of age) improved some (but not all) histological abnormalities associated with retinopathy. IQ-1S improved blood circulation, increased the functional activity of the retinal pigment epithelium, reduced the VEGF expression in the endothelial cells, and increased the expression of PEDF in the neuroretina. The result was a decrease in the degeneration of photoreceptors and neurons of the inner layers. IQ-1S significantly improved the retinal ultrastructure and increased the number of mitochondria, which were significantly reduced in the neuroretina of OXYS rats compared to Wistar rats. It seems probable that using IQ-1S can be a good prophylactic strategy to treat AMD.

Quantification of a promising JNK inhibitor and nitrovasodilator IQ-1 and its major metabolite in rat plasma by LC-MS/MS

Background: IQ-1 is a promising c-Jun-N-terminal kinase inhibitor and nitrovasodilator. An LC-MS/MS method was validated to determine IQ-1 isomers and major metabolite IQ-18 in rat plasma. Materials & methods: The analytes were extracted using ethyl acetate. The chromatographic separation was performed on a C8 column (150 × 4.6 mm, 5 μm) under acetonitrile-water (5 mM ammonium formate buffer, pH 2.93) gradient elution. Multiple reaction monitoring was used for MS/MS detection in the positive ion mode. Results: The method was fully validated over the range of 0.1-400 ng/ml (Z-isomer), 0.9-3600 ng/ml (E-isomer), 5.0-4000 (IQ-18). Conclusion: This method has been successfully applied to pharmacokinetic studies of IQ-1 and IQ-18 in rats after a single oral dose of IQ-1 (50 mg/kg).

Neuroprotective Effects of the Lithium Salt of a Novel JNK Inhibitor in an Animal Model of Cerebral Ischemia–Reperfusion

The c-Jun N-terminal kinases (JNKs) regulate many physiological processes, including inflammatory responses, morphogenesis, cell proliferation, differentiation, survival, and cell death. Therefore, JNKs represent attractive targets for therapeutic intervention. In an effort to develop improved JNK inhibitors, we synthesized the lithium salt of 11H-indeno[1,2-b]quinoxaline-11-one oxime (IQ-1L) and evaluated its affinity for JNK and biological activity in vitro and in vivo. According to density functional theory (DFT) modeling, the Li⁺ ion stabilizes the six-membered ring with the 11H-indeno[1,2-b]quinoxaline-11-one (IQ-1) oximate better than Na⁺. Molecular docking showed that the Z isomer of the IQ-1 oximate should bind JNK1 and JNK3 better than (E)-IQ-1. Indeed, experimental analysis showed that IQ-1L exhibited higher JNK1-3 binding affinity in comparison with IQ-1S. IQ-1L also was a more effective inhibitor of lipopolysaccharide (LPS)-induced nuclear factor-κB/activating protein 1 (NF-κB/AP-1) transcriptional activity in THP-1Blue monocytes and was a potent inhibitor of proinflammatory cytokine production by MonoMac-6 monocytic cells. In addition, IQ-1L inhibited LPS-induced c-Jun phosphorylation in MonoMac-6 cells, directly confirming JNK inhibition. In a rat model of focal cerebral ischemia (FCI), intraperitoneal injections of 12 mg/kg IQ-1L led to significant neuroprotective effects, decreasing total neurological deficit scores by 28, 29, and 32% at 4, 24, and 48 h after FCI, respectively, and reducing infarct size by 52% at 48 h after FCI. The therapeutic efficacy of 12 mg/kg IQ-1L was comparable to that observed with 25 mg/kg of IQ-1S, indicating that complexation with Li⁺ improved efficacy of this compound. We conclude that IQ-1L is more effective than IQ-1S in treating cerebral ischemia injury and thus represents a promising anti-inflammatory compound.

Exosomes secreted by hypoxia-preconditioned adipose-derived mesenchymal stem cells reduce neuronal apoptosis in rats with spinal cord injury

Neuronal death is the main cause of nerve function impairment after spinal cord injury (SCI). Exosome-based therapy has become a novel strategy for tissue injury repair. We designed a method to treat SCI using exosomes secreted by adipose tissue-derived stromal cells (ADSCs) under hypoxic conditions. We established a neuronal oxygen-glucose deprivation and reperfusion (OGD/R) model in vitro to simulate the hypoxic environment after SCI. We observed that exosomes derived from hypoxia-conditioned ADSCs (Hypo-exos) significantly reduced neuronal apoptosis after OGD. By establishing a rat SCI model, we found that Hypo-exos can significantly reduce the formation of cavities in the injured area and improve the functional recovery of the hind limbs of rats after injury. To explore the molecular mechanism, we conducted miRNA sequencing analysis of exosomes. Through RT-PCR, dual luciferase reporter assays and signaling pathway chip analysis, we determined that miR-499a-5p regulates the JNK3/c-jun-apoptotic signaling pathway by targeting JNK3. Furthermore, we verified the expression of the key proteins in the JNK3/c-jun-apoptotic signaling pathway by immunofluorescence and western blotting. These results support the hypothesis that Hypo-exos can reduce neuronal apoptosis after SCI and may provide new methods to treat SCI.

TBC1Domain Family Member 25 deficiency aggravates cerebral ischemia-reperfusion injury via TAK1-JNK/p38 pathway

TBC1Domain Family Member 25 (TBC1D25) is a protein that contains a TBC/RAB-GTPase activating protein (GAP) domain, which was shown to participate in autophagy in previous studies. However, the role of TBC1D25 in cerebral ischemia-reperfusion (I/R) injury remains unknown. In this study, we found that the mRNA and protein expression levels of TBC1D25 decreased in mouse brain after I/R injury and primary cortical neurons treated with oxygen and glucose deprivation/reoxygenation (OGD/R). Then TBC1D25 knockout (KO) mice were applied to demonstrate that TBC1D25 ablation aggravated cerebral I/R-induced neuronal loss and infarct size. In addition, neuronal apoptosis and inflammation were significantly potentiated in the TBC1D25-KO group. In in vitro OGD/R model, TBC1D25 knockdown can attenuate neuronal cell viability and aggravate the process of inflammation and apoptosis. Conversely, over-expression of TBC1D25 in primary neurons ameliorated the aforementioned processes. Mechanistically, RNA-sequencing (RNA-seq) analysis revealed mitogen-activated protein kinase (MAPK) signaling pathway was the most significant pathway that contributed to TBC1D25-mediated brain I/R injury process. Through experimental verification, TBC1D25 deficiency increased the phosphorylation of the transforming growth factor-β-activated kinase 1 (TAK1)-c-Jun N-terminal kinase (JNK)/p38 axis in neurons during the brain I/R injury. Furthermore, we found that TAK1 blockade abrogated the apoptosis and inflammatory response produced by TBC1D25 knockdown in vitro. In conclusion, this study is the first to demonstrate the functional significance of TBC1D25 in the pathophysiology of brain I/R injury, and the protective mechanism of TBC1D25 is dependent on the TAK1-JNK/p38 pathway.

Oximes: Novel Therapeutics with Anticancer and Anti-Inflammatory Potential

Oximes have been studied for decades because of their significant roles as acetylcholinesterase reactivators. Over the last twenty years, a large number of oximes have been reported with useful pharmaceutical properties, including compounds with antibacterial, anticancer, anti-arthritis, and anti-stroke activities. Many oximes are kinase inhibitors and have been shown to inhibit over 40 different kinases, including AMP-activated protein kinase (AMPK), phosphatidylinositol 3-kinase (PI3K), cyclin-dependent kinase (CDK), serine/threonine kinases glycogen synthase kinase 3 α/β (GSK-3α/β), Aurora A, B-Raf, Chk1, death-associated protein-kinase-related 2 (DRAK2), phosphorylase kinase (PhK), serum and glucocorticoid-regulated kinase (SGK), Janus tyrosine kinase (JAK), and multiple receptor and non-receptor tyrosine kinases. Some oximes are inhibitors of lipoxygenase 5, human neutrophil elastase, and proteinase 3. The oxime group contains two H-bond acceptors (nitrogen and oxygen atoms) and one H-bond donor (OH group), versus only one H-bond acceptor present in carbonyl groups. This feature, together with the high polarity of oxime groups, may lead to a significantly different mode of interaction with receptor binding sites compared to corresponding carbonyl compounds, despite small changes in the total size and shape of the compound. In addition, oximes can generate nitric oxide. This review is focused on oximes as kinase inhibitors with anticancer and anti-inflammatory activities. Oximes with non-kinase targets or mechanisms of anti-inflammatory activity are also discussed.

Modified middle cerebral artery occlusion model provides detailed intraoperative cerebral blood flow registration and improves neurobehavioral evaluation

BACKGROUND

Middle cerebral artery occlusion (MCAO) with 1 -h ischemia followed by reperfusion is a widely used stroke model in rodents that has significant limitations such as high mortality and severe neurological deficit hampering comprehensive neurobehavioral evaluation. The goal of this study was to establish a mouse model of 30-minute MCAO followed by 48 h of reperfusion and compare it with 1 -h MCAO followed by 24 h of reperfusion.

NEW METHOD

Here we propose a modified MCAO model that is favorable for both neurobehavioral and infarct volume evaluation. The model includes shorter ischemic time (30 min) of MCAO followed by 48 h of reperfusion and use of standardized intraoperative partial and total reperfusion, which allows for the detailed evaluation of initial and total reperfusion by means of the monitoring of CBF by LDF.

RESULTS AND COMPARISON WITH EXISTING METHOD

Intraoperative CBF parameters and infarct volume (1-h MCAO at 24 h: 69 ± 9; 30-minute MCAO at 48 h: 65 ± 14 mm³) did not significantly differ between groups. Neurological deficit was less severe in 30-minute MCAO group where mice also had significantly longer ambulatory distance and time, lower resting time, and higher vertical count on the OPF. The latency to fall in the rotarod test was significantly higher in 30-minute MCAO group. The mortality was higher after 1 -h MCAO.

CONCLUSIONS

30-minute MCAO followed by 48 h of reperfusion causes intraoperative ischemia, reperfusion and infarct volume comparable with 1 -h MCAO followed by 24 h of reperfusion but results in lower mortality with milder neurological deficit allowing for more extensive neurobehavioral evaluation.

JNK selective inhibitor, IQ-1S, protects the mice against lipopolysaccharides-induced sepsis

Sepsis is a severe systemic inflammatory response induced by infection. Innate immunity recognizes pathogen components such as lipopolysaccharides (LPS), and mediates the polarization of immune cells and the release of cytokines. However, this process is also crucial for triggering sepsis and septic shock. To investigate the potential therapeutic function of 11H-indeno [1,2-b] quinoxalin-11-one oxime (IQ-1S) to sepsis, LPS plus d-galactosamine was used to establish a sepsis mouse model. Flow cytometry was performed to catalyze T cells and macrophages in mouse spleen. ELISA assay and qRT-PCR assay were performed to estimate the expression levels of cytokines and related genes including TNF-α, IL-6, IL-1β, Nos2, Arg and Mrc. The protein levels of NF-κB, AP1, NF-Y, p-JNK2, JNK2, p-p38, p38, p-IκBα, IκBα, p-IKKβ and IKKβ were evaluated by Western blot assay. IQ-1S treatment significantly reduced mortality and lung inflammation in sepsis mice. IQ-1S treatment decreased the levels of inflammatory cytokines in sepsis mice. Polarization of M1 macrophages was suppressed by IQ-1S in vitro. IQ-1S significantly inhibited the activation of the JNK signaling pathway and reduced the phosphorylation level of JNK2 in sepsis mice. IQ-1S protected the mice against LPS-induced sepsis through inhibiting JNK signaling pathway.

Acorus tatarinowii Schott extract reduces cerebral edema caused by ischemia-reperfusion injury in rats: involvement in regulation of astrocytic NKCC1/AQP4 and JNK/iNOS-mediated signaling

Background

This study aimed to evaluate the effects of the Acorus tatarinowii Schott [Shi Chang Pu (SCP)] extract administered at the start of 2 h of middle cerebral artery occlusion (MCAo), followed by 3 d of reperfusion, and to determine mechanisms involved in anti-edema effects in the penumbra of the cerebral cortex.

Method

Rats were intraperitoneally administered the SCP extract at a dose of 0.25 g/kg (SCP-0.25 g), 0.5 g/kg (SCP-0.5 g), or 1 g/kg (SCP-1 g) at the start of MCAo.

Result

SCP-0.5 g and SCP-1 g treatments effectively reduced the cerebral infarct size, ameliorated cerebral edema, reduced blood–brain barrier permeability, and restored neurological function. SCP-0.5 g and SCP-1 g treatments markedly downregulated the levels of glial fibrillary acidic protein, Na⁺-K⁺-2Cl⁻ cotransporter type 1 (NKCC1), aquaporin 4 (AQP4), phospho-c-Jun N-terminal kinase (p-JNK)/JNK, inducible nitric oxide synthase (iNOS), 3-nitrotyrosine, intercellular adhesion molecule-1 (ICAM-1), matrix metalloproteinase-9 (MMP-9), vascular endothelial growth factor-A (VEGF-A), and zonula occluden-1 (ZO-1) and upregulated ZO-3 expression in the penumbra of the cerebral cortex 3 d after reperfusion.

Conclusions

SCP-0.5 g and SCP-1 g treatments exert neuroprotective effects against cerebral infarction and cerebral edema partially by mitigating astrocytic swelling and blood–brain barrier disruption. Moreover, the anti-cerebral edema effects of SCP extract treatments are possibly associated with the downregulation of astrocytic NKCC1/AQP4 and JNK/iNOS-mediated ICAM-1/MMP-9 signaling in the penumbra of the cerebral cortex 3 d after reperfusion.

Alarmins and c-Jun N-Terminal Kinase (JNK) Signaling in Neuroinflammation

Neuroinflammation is involved in the progression or secondary injury of multiple brain conditions, including stroke and neurodegenerative diseases. Alarmins, also known as damage-associated molecular patterns, are released in the presence of neuroinflammation and in the acute phase of ischemia. Defensins, cathelicidin, high-mobility group box protein 1, S100 proteins, heat shock proteins, nucleic acids, histones, nucleosomes, and monosodium urate microcrystals are thought to be alarmins. They are released from damaged or dying cells and activate the innate immune system by interacting with pattern recognition receptors. Being principal sterile inflammation triggering agents, alarmins are considered biomarkers and therapeutic targets. They are recognized by host cells and prime the innate immune system toward cell death and distress. In stroke, alarmins act as mediators initiating the inflammatory response after the release from the cellular components of the infarct core and penumbra. Increased c-Jun N-terminal kinase (JNK) phosphorylation may be involved in the mechanism of stress-induced release of alarmins. Putative crosstalk between the alarmin-associated pathways and JNK signaling seems to be inherently interwoven. This review outlines the role of alarmins/JNK-signaling in cerebral neurovascular inflammation and summarizes the complex response of cells to alarmins. Emerging anti-JNK and anti-alarmin drug treatment strategies are discussed.

Neuroprotective Effects of a Novel Inhibitor of c-Jun N-Terminal Kinase in the Rat Model of Transient Focal Cerebral Ischemia

A novel specific inhibitor of c-Jun N-terminal kinase, 11H-indeno[1,2-b]quinoxalin-11-one oxime sodium salt (IQ-1S), has a high affinity to JNK3 compared to JNK1/JNK2. The aim of this work was to study the mechanisms of neuroprotective activity of IQ-1S in the models of reversible focal cerebral ischemia (FCI) in Wistar rats. The animals were administered with an intraperitoneal injection of IQ-1S (5 and 25 mg/kg) or citicoline (500 mg/kg). Administration of IQ-1S exerted a pronounced dose-dependent neuroprotective effect, not inferior to the effects of citicoline. Administration of IQ-1S at doses of 5 and 25 mg/kg reduced the infarct size by 20% and 50%, respectively, 48 h after FCI, whereas administration of citicoline reduced the infarct size by 34%. The administration of IQ-1S was associated with a faster amelioration of neurological status. Control rats showed a 2.0-fold increase in phospho-c-Jun levels in the hippocampus compared to the corresponding values in sham-operated rats 4 h after FCI. Administration of IQ-1S at a dose of 25 mg/kg reduced JNK-dependent phosphorylation of c-Jun by 20%. Our findings suggest that IQ-1S inhibits JNK enzymatic activity in the hippocampus and protects against stroke injury when administered in the therapeutic and prophylactic regimen in the rat model of FCI.

Hemostimulating Effects of c-Jun N-Terminal Kinase (JNK) Inhibitor during Cytostatic Myelosuppression and Mechanisms of Their Development

The hemostimulating effects of c-Jun N-terminal kinase (JNK) inhibitor were examined on the mouse model of myelosuppression provoked by 5-fluorouracil. Blockade of JNK during postcytostatic period accelerated recovery of granulomonocytopoiesis and erythropoiesis. It also increased the content of neutrophilic granulocytes and erythroid cells in the hematopoietic tissue and elevated the counts of neutrophils and reticulocytes in the peripheral blood. The development of these phenomena resulted from elevated content and up-regulated functional activity of bone marrow hematopoietic progenitors associated with the direct action of JNK inhibitor on these progenitors and enhanced secretion of hemopoietins by stromal elements of the hematopoiesis-inducing microenvironment.

Potent Natural Antioxidant Carveol Attenuates MCAO-Stress Induced Oxidative, Neurodegeneration by Regulating the Nrf-2 Pathway

Ischemic stroke is a severe neurological disorder with a high prevalence rate in developed countries. It is characterized by permanent or transient cerebral ischemia and it activates syndrome of pathological events such as membrane depolarization, glutamate excitotoxicity, and intracellular calcium buildup. Carveol is widely employed as anti-inflammatory and antioxidant in traditional Chinese medicine. In the present study, the neuroprotective effects of post-treated carveol were demonstrated against transient middle cerebral artery occlusion (MCAO) induced focal ischemic cerebral injury. Male Sprague Dawley (SD) rats were subjected to two different experimental protocols to determine the dose and effects of carveol, and to demonstrate the underlying role of the nuclear factor E2-related factor (Nrf2) pathway. Our results showed that MCAO induced marked neuronal injury in the ipsilateral cortex and striatum associated with higher inflammatory cytokines expression, along with apoptotic markers such as caspase-3 and the phosphorylated c-Jun N-terminal kinase (JNK). Furthermore, MCAO induced a marked increase in oxidative stress as evidenced by high lipid peroxidase (LPO) content accompanied by the depressed antioxidant system. Carveol significantly reversed the oxidative stress and downregulated inflammatory cascades by enhancing endogenous antioxidant mechanisms including the Nrf2 gene, which critically regulates the expression of several downstream antioxidants. Further, to determine the possible involvement of Nrf2 in carveol mediated neuroprotection, we antagonized Nrf2 by all-trans retinoic acid (ATRA), and such treatment abrogated the protective effects of carveol accompanied with exaggerated neuronal toxicity as demonstrated by higher infarction area. The target effects of carveol were further supported by molecular docking analysis of drug-protein interactions. Together, our findings suggest that carveol could activate endogenous master anti-oxidant Nrf2, which further regulates the expression of downstream antioxidants, eventually ameliorating MCAO-induced neuroinflammation and neurodegeneration.

Arene-Ruthenium(II) Complexes Containing 11H-Indeno[1,2-b]quinoxalin-11-one Derivatives and Tryptanthrin-6-oxime: Synthesis, Characterization, Cytotoxicity, and Catalytic Transfer Hydrogenation of Aryl Ketones

A series of novel mono- and binuclear arene-ruthenium(II) complexes [(p-cym)Ru(L)Cl] containing 11H-indeno[1,2-b]quinoxalin-11-one derivatives or tryptanthrin-6-oxime were synthesized and characterized by X-ray crystallography, IR, NMR spectroscopy, cyclic voltammetry, and elemental analysis. Theoretical calculations invoking singlet state geometry optimization, solvation effects, and noncovalent interactions were done using density functional theory (DFT). DFT calculations were also applied to evaluate the electronic properties, and time-dependent DFT was applied to clarify experimental UV-vis results. Cytotoxicity for cancerous and noncancerous human cell lines was evaluated with cell viability MTT assay. Complexes demonstrated a moderate cytotoxic effect toward cancerous human cell line PANC-1. The catalytic activity of the complexes was evaluated in transfer hydrogenation of aryl ketones. All complexes exhibited good catalytic activity and functional group tolerance.

Antihypertensive activity of a new c-Jun N-terminal kinase inhibitor in spontaneously hypertensive rats

c-Jun N-terminal kinases (JNKs) are involved in the myocardial and aortic remodeling, increased arterial tone, and arterial blood pressure elevation associated with hypertension. The aim of the present study was to investigate the antihypertensive effect of a new JNK inhibitor, 1H-indeno[1,2-b]quinoxalin-11-one oxime sodium salt (IQ-1S), on spontaneously hypertensive rats (SHRs). Experiments were performed using normotensive Wistar-Kyoto (WKY) rats and SHRs. Experimental groups of SHRs received IQ-1S intragastrically for 6 weeks in daily doses of 5 and 50 mg/kg; experimental groups of WKY rats received 50 mg/kg IQ-1S according to the same regimen. The IQ-1S administration regimen induced decreases in systolic blood pressure, mean arterial blood pressure, total peripheral resistance, blood viscosity, hematocrit, myocardial cell cross-sectional area, and aortic wall thickness in SHRs vs untreated SHRs. There were no significant differences in systolic blood pressure values between the control and experimental groups of WKY rats during the treatment period. A concentration-dependent decrease in the tone of carotid arterial rings isolated from SHRs was observed after JNK inhibitor application in vitro. Application of the JNK inhibitor diminished endothelin-1 secretion by human umbilical vein endothelial cells in vitro. The main mechanisms of the antihypertensive effect of IQ-1S included the attenuation of blood viscosity due to decreased hematocrit, a vasodilatory effect on arterial smooth muscle cells, and a decrease in endothelin-1 production by endothelial cells.

Inhibitory effect of IQ-1S, a selective c-Jun N-terminal kinase (JNK) inhibitor, on phenotypical and cytokine-producing characteristics in human macrophages and T-cells

c-Jun N-terminal kinase (JNK) is a critical mitogen activated protein kinase (MAPK) implicated in inflammatory processes, with IQ-1S (11H-indeno[1,2-b]quinoxalin-11-one oxime sodium salt) being a high-affinity JNK inhibitor with pronounced anti-inflammatory properties. Here, we studied direct effects of IQ-1S on phenotypical and cytokine-producing characteristics of activated human monocytes/macrophages and T cells in vitro. Purified monocyte/macrophage cells were activated by bacterial lipopolysaccharide (LPS, 1 μg/ml) for 24 h, while T cells were activated by particles conjugated with antibodies (Abs) against human CD2, CD3, and CD28 for 48 h. Treatment with IQ-1S (0.5-25 μМ) in the presence of LPS reduced percentages of CD197 (CCR7)-positive cells in macrophage cultures, without affecting CD16⁺ (FcγRIII, low-affinity Fc-receptor), CD119⁺ (interferon-γ receptor 1), and CD124⁺ (IL-4 receptor α-subunit) cells. In addition, IQ-1S reduced production of tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, and IL-10 in macrophage cultures. In activated T cell cultures, IQ-1S decreased CD25⁺ cell numbers in both CD4-positive and CD4-negative T cell compartments. Central memory СD45RA^-/СD197⁺ and effector memory СD45RA^-/СD197^- T cells were more sensitive to IQ-1S-mediated suppression, as compared to naïve СD45RA⁺/СD197⁺ and terminally-differentiated effector СD45RA⁺/СD197^- T cells. IQ-1S also suppressed T-cell cytokine production (IL-2, interferon-ɣ, IL-4, and IL-10). Collectively, the results suggest that both human macrophage and T cells could be immediate cell targets for IQ-1S-based anti-inflammatory immunotherapy. IQ-1S-mediated suppressive effects were unlikely to be associated with macrophage/T helper polariation.

Electrosprayed poly(lactic-co-glycolic acid) particles as a promising drug delivery system for the novel JNK inhibitor IQ-1

Mitogen-activated protein kinases (MAPKs), including c-Jun N-terminal kinase (JNK), play important role in the regulation of pro-inflammatory cytokine secretion and signaling cascades. Therefore, JNKs are key targets for the treatment of cytokine/JNK-driven diseases. Herein, we developed electrospray poly(lactic-co-glycolic acid) (PLGA) microparticles doped with novel JNK inhibitor 11H-indeno[1,2-b]quinoxalin-11-one oxime (IQ-1). Optimized electrospray parameters allowed us to produce IQ-1-doped microparticles with round shape, smooth and non-porous surface, and mean diameter of 0.9-1.3 μm. We have shown that IQ-1 was well integrated into the polymer matrix and had a prolonged release in two steps via non-Fickian release. The fabricated particles doped with IQ-1 exhibited anti-inflammatory effects, as indicated by inhibited neutrophil activation and cytokine secretion by human monocytic MonoMac-6 cells. Overall, our study demonstrates that PLGA microparticles doped with a novel JNK inhibitor (IQ-1) could be a promising delivery system for treatment of JNK-mediated diseases.

Pharmacological Characterizations of anti-Dementia Memantine Nitrate via Neuroprotection and Vasodilation in Vitro and in Vivo

We have previously designed and synthesized a series of novel memantine nitrates, and some of them have shown neuroprotective effects; however, the detailed mechanisms remain unknown. In this study, we demonstrated that MN-12, one of the memantine nitrates, concentration-dependently protected against glutamate-induced neurotoxicity in rat primary cultured cerebellar granule neurons (CGNs). Western blotting assays revealed that MN-12 might possess neuroprotective effects through the inhibition of ERK pathway and activation of PI3K/Akt pathway concurrently. Moreover, MN-12 concentration-dependently dilated precontracted rat middle cerebral artery through activation of NO-cGMP pathway ex vivo. In the 2-vessel occlusion (2VO) rat model, MN-12 alleviated the impairments of spatial memory and motor dysfunction possibly via neuroprotection and improvement of the cerebral blood flow. Furthermore, the results of preliminary pharmacokinetic studies showed that MN-12 might quickly distribute to the major organs including the brain, indicating that MN-12 could penetrate the blood-brain barrier. Taken together, MN-12 might provide multifunctional therapeutic benefits for dementia associated with Alzheimer's disease, vascular dementia, and ischemic stroke, via neuroprotection and vessel dilation to improve the cerebral blood flow.

cGMP-dependent protein kinase I in vascular smooth muscle cells improves ischemic stroke outcome in mice

Recent works highlight the therapeutic potential of targeting cyclic guanosine monophosphate (cGMP)-dependent pathways in the context of brain ischemia/reperfusion injury (IRI). Although cGMP-dependent protein kinase I (cGKI) has emerged as a key mediator of the protective effects of nitric oxide (NO) and cGMP, the mechanisms by which cGKI attenuates IRI remain poorly understood. We used a novel, conditional cGKI knockout mouse model to study its role in cerebral IRI. We assessed neurological deficit, infarct volume, and cerebral perfusion in tamoxifen-inducible vascular smooth muscle cell-specific cGKI knockout mice and control animals. Stroke experiments revealed greater cerebral infarct volume in smooth muscle cell specific cGKI knockout mice (males: 96 ± 16 mm3; females: 93 ± 12 mm3, mean±SD) than in all control groups: wild type (males: 66 ± 19; females: 64 ± 14), cGKI control (males: 65 ± 18; females: 62 ± 14), cGKI control with tamoxifen (males: 70 ± 8; females: 68 ± 10). Our results identify, for the first time, a protective role of cGKI in vascular smooth muscle cells during ischemic stroke injury. Moreover, this protective effect of cGKI was found to be independent of gender and was mediated via improved reperfusion. These results suggest that cGKI in vascular smooth muscle cells should be targeted by therapies designed to protect brain tissue against ischemic stroke.

JNK-IN-8, a c-Jun N-terminal kinase inhibitor, improves functional recovery through suppressing neuroinflammation in ischemic stroke

C‐Jun N‐terminal kinase (JNK) is a pivotal MAPK (mitogen‐activated protein kinase), which activated by ischemia brain injury and plays a fairly crucial function in cerebral ischemic injury. Emerging studies demonstrated that JNK‐IN‐8 (a JNK inhibitor with high specificity) regulates traumatic brain injury through controlling neuronal apoptosis and inflammation. However, the function of JNK‐IN‐8 in ischemic stroke and the mechanisms underlying of JNK‐IN‐8 about neuroprotection are not well understood. In this work, male rats were treated with JNK‐IN‐8 after transient middle cerebral artery occlusion, and then the modified improved neurological function score (mNSS), the foot‐fault test (FFT), interleukin‐1β (IL‐1β), IL‐6, and tumor necrosis factor‐α (TNF‐α) levels were assessed. We found that JNK‐IN‐8‐treated rats with MCAO exerted an observable melioration in space learning as tested by the improved mNSS, and showed sensorimotor functional recovery as measured by the FFT. JNK‐IN‐8 also played anti‐inflammatory roles as indicated through decreased activation of microglia and decreased IL‐6, IL‐1β, and TNF‐α expression. Furthermore, JNK‐IN‐8 suppressed the activation of JNK and nuclear factor‐κB (NF‐κB) signaling as indicated by the decreased level of phosphorylated‐JNK and p65. All data demonstrate that JNK‐IN‐8 inhibits neuroinflammation and improved neurological function by inhibiting JNK/NF‐κB and is a promising agent for the prevention of ischemic brain injury.

Protective Effects of a New C-Jun N-terminal Kinase Inhibitor in the Model of Global Cerebral Ischemia in Rats

c-Jun N-terminal kinase (JNK) is activated by various brain insults and is implicated in neuronal injury triggered by reperfusion-induced oxidative stress. Some JNK inhibitors demonstrated neuroprotective potential in various models, including cerebral ischemia/reperfusion injury. The objective of the present work was to study the neuroprotective activity of a new specific JNK inhibitor, IQ-1S (11H-indeno[1,2-b]quinoxalin-11-one oxime sodium salt), in the model of global cerebral ischemia (GCI) in rats compared with citicoline (cytidine-5'-diphosphocholine), a drug approved for the treatment of acute ischemic stroke and to search for pleiotropic mechanisms of neuroprotective effects of IQ-1S. The experiments were performed in a rat model of ischemic stroke with three-vessel occlusion (model of 3VO) affecting the brachiocephalic artery, the left subclavian artery, and the left common carotid artery. After 7-min episode of GCI in rats, 25% of animals died, whereas survived animals had severe neurological deficit at days 1, 3, and 5 after GCI. At day 5 after GCI, we observing massive loss of pyramidal neurons in the hippocampal CA1 area, increase in lipid peroxidation products in the brain tissue, and decrease in local cerebral blood flow (LCBF) in the parietal cortex. Moreover, blood hyperviscosity syndrome and endothelial dysfunction were found after GCI. Administration of IQ-1S (intragastrically at a dose 50 mg/kg daily for 5 days) was associated with neuroprotective effect comparable with the effect of citicoline (intraperitoneal at a dose of 500 mg/kg, daily for 5 days).The neuroprotective effect was accompanied by a decrease in the number of animals with severe neurological deficit, an increase in the number of animals with moderate degree of neurological deficit compared with control GCI group, and an increase in the number of unaltered neurons in the hippocampal CA1 area along with a significant decrease in the number of neurons with irreversible morphological damage. In rats with IQ-1S administration, the LCBF was significantly higher (by 60%) compared with that in the GCI control. Treatment with IQ-1S also decreases blood viscosity and endothelial dysfunction. A concentration-dependent decrease (IC50 = 0.8 ± 0.3 μM) of tone in isolated carotid arterial rings constricted with phenylephrine was observed after IQ-1S application in vitro. We also found that IQ-1S decreased the intensity of the lipid peroxidation in the brain tissue in rats with GCI. 2.2-Diphenyl-1-picrylhydrazyl scavenging for IQ-1S in acetonitrile and acetone exceeded the corresponding values for ionol, a known antioxidant. Overall, these results suggest that the neuroprotective properties of IQ-1S may be mediated by improvement of cerebral microcirculation due to the enhanced vasorelaxation, beneficial effects on blood viscosity, attenuation of the endothelial dysfunction, and antioxidant/antiradical IQ-1S activity.

Synthesis, biological evaluation, and molecular modeling of 11H-indeno[1,2-b]quinoxalin-11-one derivatives and tryptanthrin-6-oxime as c-Jun N-terminal kinase inhibitors

c-Jun N-terminal kinases (JNKs) play a central role in many physiologic and pathologic processes. We synthesized novel 11H-indeno[1,2-b]quinoxalin-11-one oxime analogs and tryptanthrin-6-oxime (indolo[2,1-b]quinazoline-6,12-dion-6-oxime) and evaluated their effects on JNK activity. Several compounds exhibited sub-micromolar JNK binding affinity and were selective for JNK1/JNK3 versus JNK2. The most potent compounds were 10c (11H-indeno[1,2-b]quinoxalin-11-one O-(O-ethylcarboxymethyl) oxime) and tryptanthrin-6-oxime, which had dissociation constants (K_d) for JNK1 and JNK3 of 22 and 76 nM and 150 and 275 nM, respectively. Molecular modeling suggested a mode of binding interaction at the JNK catalytic site and that the selected oxime derivatives were potentially competitive JNK inhibitors. JNK binding activity of the compounds correlated with their ability to inhibit lipopolysaccharide (LPS)-induced nuclear factor-κB/activating protein 1 (NF-κB/AP-1) activation in human monocytic THP-1Blue cells and interleukin-6 (IL-6) production by human MonoMac-6 cells. Thus, oximes with indenoquinoxaline and tryptanthrin nuclei can serve as specific small-molecule modulators for mechanistic studies of JNK, as well as potential leads for the development of anti-inflammatory drugs.

c-Jun N-Terminal Kinases (JNKs) in Myocardial and Cerebral Ischemia/Reperfusion Injury

In this article, we review the literature regarding the role of c-Jun N-terminal kinases (JNKs) in cerebral and myocardial ischemia/reperfusion injury. Numerous studies demonstrate that JNK-mediated signaling pathways play an essential role in cerebral and myocardial ischemia/reperfusion injury. JNK-associated mechanisms are involved in preconditioning and post-conditioning of the heart and the brain. The literature and our own studies suggest that JNK inhibitors may exert cardioprotective and neuroprotective properties. The effects of modulating the JNK-depending pathways in the brain and the heart are reviewed. Cardioprotective and neuroprotective mechanisms of JNK inhibitors are discussed in detail including synthetic small molecule inhibitors (AS601245, SP600125, IQ-1S, and SR-3306), ion channel inhibitor GsMTx4, JNK-interacting proteins, inhibitors of mixed-lineage kinase (MLK) and MLK-interacting proteins, inhibitors of glutamate receptors, nitric oxide (NO) donors, and anesthetics. The role of JNKs in ischemia/reperfusion injury of the heart in diabetes mellitus is discussed in the context of comorbidities. According to reviewed literature, JNKs represent promising therapeutic targets for protection of the brain and the heart against ischemic stroke and myocardial infarction, respectively. However, different members of the JNK family exert diverse physiological properties which may not allow for systemic administration of non-specific JNK inhibitors for therapeutic purposes. Currently available candidate JNK inhibitors with high therapeutic potential are identified. The further search for selective JNK3 inhibitors remains an important task.

Targeting thrombomodulin to circulating red blood cells augments its protective effects in models of endotoxemia and ischemia-reperfusion injury

Endothelial thrombomodulin (TM) regulates coagulation and inflammation via several mechanisms, including production of activated protein C (APC). Recombinant APC and soluble fragments of TM (sTM) have been tested in settings associated with insufficiency of the endogenous TM/APC pathway, such as sepsis. We previously designed a fusion protein of TM [single-chain variable fragment antibody (scFv)/TM] targeted to red blood cells (RBCs) to improve pharmacokinetics and antithrombotic effects without increasing bleeding. Here, scFv/TM was studied in mouse models of systemic inflammation and ischemia-reperfusion injury. Injected concomitantly with or before endotoxin, scFv/TM provided more potent protection against liver injury and release of pathological mediators than sTM, showing similar efficacy at up to 50-fold lower doses. scFv/TM provided protection when injected after endotoxin, whereas sTM did not, and augmented APC production by thrombin ∼50-fold more than sTM. However, scFv/TM injected after endotoxin did not reduce thrombin/antithrombin complexes; nor did antibodies that block APC anticoagulant activity suppress the prophylactic anti-inflammatory effect of scFv/TM. Therefore, similar to endogenous TM, RBC-anchored scFv/TM activates several protective pathways. Finally, scFv/TM was more effective at reducing cerebral infarct volume and alleviated neurological deficits than sTM after cerebral ischemia/reperfusion injury. These results indicate that RBC-targeted scFv/TM exerts multifaceted cytoprotective effects and may find utility in systemic and focal inflammatory and ischemic disorders.-Carnemolla, R., Villa, C. H., Greineder, C. F., Zaitseva, S., Patel, K. R., Kowalska, M. A., Atochin, D. N., Cines, D. B., Siegel, D. L., Esmon, C. T., Muzykantov, V. R. Targeting thrombomodulin to circulating red blood cells augments its protective effects in models of endotoxemia and ischemia-reperfusion injury.