Effects Of Carbon Monoxide-releasing Molecules Research Articles

Carbon monoxide‑releasing molecules protect against blue light exposure and inflammation in retinal pigment epithelial cells.

The most common cause of vision loss among the elderly is age-related macular degeneration (AMD). The aim of the present study was to investigate the potential cytoprotective and anti-inflammatory effects of carbon monoxide-releasing molecules (CORMs), and their ability to activate the expression of nuclear factor erythroid 2-related factor 2 (Nrf2)-related genes in human retinal pigment epithelium (RPE) cells, as well as the inhibition of endothelial cell migration. It was first determined that CORM2 and CORM3 suppressed blue light-induced cell damage. In addition, a decrease in the level of cleaved poly(ADP-ribose) polymerase 1 protein and dissipation of mitochondrial membrane potential were considered to reflect the anti-apoptotic activity of CORMs. Furthermore, CORM2 induced Nrf-2 activation and the expression of the Nrf2-related genes heme oxygenase-1 and glutamate-cysteine ligase. Pretreatment with CORM2 abolished the blue light-induced increase in oxidative stress, suggesting that CORM2-induced antioxidant activity was involved in the cytoprotection against blue light. It was also demonstrated that CORMs markedly suppressed tumor necrosis factor (TNF)α-induced intercellular adhesion molecule-1 expression. Moreover, it was further observed that CORMs exert their inhibitory effects through blocking nuclear factor-κB/p65 nuclear translocation and IκBα degradation in TNFα-treated RPE cells. It was observed that CORM2, but not CORM3, protected against oxidative stress-induced cell damage. CORMs abolished vascular endothelial growth factor-induced migration of endothelial cells. The findings of the present study demonstrated the cytoprotective, antioxidant and anti-inflammatory effects of CORMs on RPE cells and anti-angiogenic effects on endothelial cells, suggesting the potential clinical application of CORMs as anti-AMD agents.

Suppressive effect of CORM-2 on platelet α-granule exocytosis in sepsis via SNARE/Munc18b complex formation

To investigate the suppressive effect of carbon monoxide-releasing molecule II (CORM-2) on LPS induced platelet α-granule exocytosis in sepsis via soluble N-ethylmaleimide-sensitive factor attached protein receptor/mammalian uncoordinated 18b (SNARE/Munc18b) complex formation. Blood was collected from healthy volunteers' cubital vein, then platelets were isolated by differential centrifugation. Platelets were randomly divided into 5 groups. The control group did not undergo any treatment, the LPS group received 10 mg/L LPS simulation, the CORM-2 group and iCORM-2 group underwent LPS simulation and immediate administration of CORM-2 (10 μmol/L and 50 μmol/L) or iCORM-2 (50 μmol/L), respectively. Samples were incubated in a CO2-incubator at 37 °C, 95% humidity, and 5% CO2. Platelet α-granule contents were detected by using standard enzyme linked immunosorbent assay (ELISA), including platelet factor 4 (PF4), platelet derived growth factor-BB (PDGF-BB), and matrix metalloproteinase-2 (MMP-2). The expression of P-selectin was detected by flow cytometer. Transmission electron microscope and immunofluorescence microscope was used to assess platelet α-granules distribution. Expressions of Munc18b and SNARE proteins including vesicle-associated membrane protein-8 (VAMP-8), synaptosomal-associated protein-23 (SNAP-23) and syntaxin-11 (STX-11) were detected by Western Bolt. The SNARE/Munc18b complex formation was detected by immunoprecipitation. Compared with the control group, levels of PF4, PDGF-BB, MMP-2 and P-selectin in LPS induced platelets were found to markedly elevated, while CORM-2 (10 μmol/L and 50 μmol/L) could decrease platelet α-granule contents exocytosis: [PF4 (μg/L): 7.69±0.58, 6.03±0.71 vs. 10.13±0.82; PDGF-BB (μg/L): 112.71±1.79, 102.91±5.86 vs. 128.78±1.39; MMP-2 (ng/L): 32.94±2.73, 27.58±3.36 vs. 53.26±1.21; P-selectin: (17.14±0.57)%, (15.35±0.68)% vs. (23.78±0.62)%; all P < 0.01]. Transmission electron microscope and immunofluorescence microscope showed that the extent of platelet α-granules assembled to platelet plasma membrane was significantly decreased following CORM-2 treatment. Compared with the control group, the expressions of Munc18b and SNARE proteins and SNARE/Munc18b complex formation in LPS-stimulated platelets were significantly increased, while CORM-2 (10 μmol/L and 50 μmol/L) inhibited these elevations (Munc18b/GAPDH: 0.80±0.08, 0.69±0.01 vs. 0.99±0.09; VAMP-8/GAPDH: 0.72±0.09, 0.50±0.12 vs. 1.18±0.14; SNAP-23/GAPDH: 1.18±0.22, 0.63±0.10 vs. 1.90±0.08; STX-11/GAPDH: 0.76±0.02, 0.57±0.08 vs. 1.16±0.23; VAMP-8/Munc18b: 0.65±0.09, 0.53±0.07 vs. 1.21±0.20; SNAP-23/Munc18b: 0.85±0.07, 0.55±0.09 vs. 1.26±0.08; STX-11/Munc18b: 0.78±0.05, 0.61±0.10 vs. 1.39±0.16; all P < 0.01). Above all, the data showed a dose dependent change. We could suggest that CORM-2 suppressed α-granule exocytosis in LPS-stimulated platelets and the potential mechanisms might involve SNARE/Munc18b complex formation.

Carbon Monoxide Improves Neurologic Outcomes by Mitochondrial Biogenesis after Global Cerebral Ischemia Induced by Cardiac Arrest in Rats.

Mitochondrial dysfunction contributes to brain injury following global cerebral ischemia after cardiac arrest. Carbon monoxide treatment has shown potent cytoprotective effects in ischemia/reperfusion injury. This study aimed to investigate the effects of carbon monoxide-releasing molecules on brain mitochondrial dysfunction and brain injury following resuscitation after cardiac arrest in rats. A rat model of cardiac arrest was established by asphyxia. The animals were randomly divided into the following 3 groups: cardiac arrest and resuscitation group, cardiac arrest and resuscitation plus carbon monoxide intervention group, and sham control group (no cardiac arrest). After the return of spontaneous circulation, neurologic deficit scores (NDS) and S-100B levels were significantly decreased at 24, 48, and 72 h, but carbon monoxide treatment improved the NDS and S-100B levels at 24 h and the 3-day survival rates of the rats. This treatment also decreased the number of damaged neurons in the hippocampus CA1 area and increased the brain mitochondrial activity. In addition, it increased mitochondrial biogenesis by increasing the expression of biogenesis factors including peroxisome proliferator-activated receptor-γ coactivator-1α, nuclear respiratory factor-1, nuclear respiratory factor-2 and mitochondrial transcription factor A. Thus, this study showed that carbon monoxide treatment alleviated brain injury after cardiac arrest in rats by increased brain mitochondrial biogenesis.

Effects of carbon monoxide-releasing molecules on pulmonary vasoreactivity in isolated perfused lungs

In addition to its renowned poisonous effects, carbon monoxide (CO) is being recognized for its beneficial actions on inflammatory and vasoregulatory pathways, particularly when applied at low concentrations via CO-releasing molecules (CO-RMs). In the lung, CO gas and CO-RMs are suggested to decrease pulmonary vascular tone and hypoxic pulmonary vasoconstriction (HPV). However, the direct effect of CO-RMs on the pulmonary vasoreactivity in isolated lungs has not yet been investigated. We assessed the effect of CORM-2 and CORM-3 on the pulmonary vasculature during normoxia and acute hypoxia (1% oxygen for 10 min) in isolated ventilated and perfused mouse lungs. The effects were compared with those of inhaled CO gas (10%). The interaction of CORM-2 or CO with cytochrome P-450 (CYP) was measured simultaneously by tissue spectrophotometry. Inhaled CO decreased HPV and vasoconstriction induced by the thromboxane mimetic U-46619 but did not alter KCl-induced vasoconstriction. In contrast, concentrations of CORM-2 and CORM-3 used to elicit beneficial effects on the systemic circulation did not affect pulmonary vascular tone. High concentration of CO-RMs or long-term application induced a continuous increase in normoxic pressure. Inhaled CO showed spectral alterations correlating with the inhibition of CYP. In contrast, during application of CORM-2 spectrophotometric signs of interaction with CYP could not be detected. Application of CO-RMs in therapeutic doses in isolated lungs neither decreases pulmonary vascular tone and HPV nor does it induce spectral alterations that are characteristic of CO-inhibited CYP. High doses, however, may cause pulmonary vasoconstriction.

Anti-inflammatory Effects of Carbon Monoxide-Releasing Molecule on Trinitrobenzene Sulfonic Acid-Induced Colitis in Mice

Recent findings indicate that carbon monoxide (CO) in non-toxic doses exerts a beneficial anti-inflammatory action in various experimental models. However, the precise anti-inflammatory mechanism of CO in the intestine remains unclear. Here, we assessed the effects of a novel water-soluble CO-releasing molecule, CORM-3, on trinitrobenzene sulfonic acid (TNBS)-induced colitis in mice. To induce colitis, C57BL/6 male mice received an enema of TNBS. CORM-3 or its inactive compound, iCORM-3, were administered intraperitoneally, once immediately before, and twice daily after receiving an enema of TNBS. Three days after TNBS administration, the distal colon was removed, assessed for colonic damage and histological scores, polymorphonuclear leukocyte recruitment (tissue-associated myeloperoxidase, MPO activity), and TNF-α, IFN-γ and IL-17A expression (mRNA and protein levels in the colon mucosa). CD4(+) T cells isolated from murine spleens were stimulated with anti-CD3/CD28, in the presence or absence of CORM-3/iCORM-3. The cell supernatants were assessed for TNF-α and IFN-γ expression, 24h following stimulation. Colonic damage and histological scores were significantly increased in TNBS-induced mice compared to sham-operated mice. Tissue-associated MPO activity and expression of TNF-α, IFN-γ, and IL-17A in the colonic mucosa were higher in TNBS-induced colitis mice. The above changes were attenuated in CORM-3-treated mice. Further, CORM-3 was effective in reducing TNF-α and IFN-γ production in anti-CD3/CD28-stimulated CD4(+) T cells. These findings indicate that CO released from CORM-3 ameliorates inflammatory responses in the colon of TNBS-challenged mice at least in part through a mechanism that involves the suppression of inflammatory cell recruitment/activation.

Inhibition of platelet aggregation by carbon monoxide-releasing molecules (CO-RMs): comparison with NO donors

Carbon monoxide (CO) and CO-releasing molecules (CO-RMs) inhibit platelet aggregation in vitro. Herein, we compare the anti-platelet action of CORM-3, which releases CO rapidly (t ½ 1 min), and CORM-A1, which slowly releases CO (t½ = 21 min). The anti-platelet effects of NO donors with various kinetics of NO release were studied for comparison. The effects of CO-RMs and NO donors were analyzed in washed human platelets (WP), platelets rich plasma (PRP), or whole blood (WB) using aggregometry technique. CORM-3 and CORM-A1 inhibited platelet aggregation in human PRP, WP, or WB, in a concentration-dependent manner. In all three preparations, CORM-A1 was more potent than CORM-3. Inhibition of platelets aggregation by CORM-A1 was not significantly affected by a guanylate cyclase inhibitor (ODQ) and a phosphodiesterase-5 inhibitor, sildenafil. In contrast, inhibition of platelet aggregation by NO donors was more potent with a fast NO releaser (DEA-NO, t ½ = 2 min) than slow NO releasers such as PAPA-NO (t ½ = 15 min) or other slow NO donors. Predictably, the anti-platelet effect of DEA-NO and other NO donors was reversed by ODQ while potentiated by sildenafil. In contrast to NO donors which inhibit platelets proportionally to the kinetics of NO released via activation of soluble guanylate cyclase (sGC), the slow CO-releaser CORM-A1 is a superior anti-platelet agent as compared to CORM-3 which releases CO instantly. The anti-platelet action of CO-RMs does not involve sGC activation. Importantly, CORM-A1 or its derivatives representing the class of slow CO releasers display promising pharmacological profile as anti-platelet agents.

Effects of carbon monoxide-releasing molecules on cGMP levels and soluble guanylate cyclase activity

Effects of carbon monoxide-releasing molecules on cGMP levels and soluble guanylate cyclase activity

Beneficial effects of carbon monoxide-releasing molecules on post-ischemic myocardial recovery

There is increasing evidence corroborating a protective role of carbon monoxide releasing molecules (CORMs) in injured tissues. Carbon monoxide (CO) carriers have been recently developed as a pharmacological tool to simulate the effect of heme oxygenase-1-derived CO. The effects of CORM-3, a water-soluble CO releaser, on the incidence of reperfusion-induced ventricular fibrillation (VF) and tachycardia (VT) were studied in isolated rat hearts. Hearts were treated with different doses of CORM-3 before the induction of 30 min global ischemia followed by 120 min reperfusion. We found that at concentrations of 25 μM and 50 μM of CORM-3 promoted a significant reduction in the incidence of VF and VT. Thus, the incidence of VF was reduced by 67% ( p < 0.05) and 92% ( p < 0.05) with 25 μM and 50 μM of CORM-3, respectively. The protective effect of CORM-3 on the incidence of VT followed the same pattern. The antiarrhythmic protection was associated with a marked attenuation in infarct size, significant decreases in cellular Na + and Ca 2+ gains and K + loss. Consequently, the recovery of post-ischemic function was significantly improved. In conclusion, CORM-3 exerts beneficial effects against ischemia/reperfusion-induced injury through its abilities to release CO which mediates a cardioprotective action by regulating tissue Na +, K +, and Ca 2+ levels.