Qi-Hai Gong

Hydrogen Sulfide Attenuated Tumor Necrosis Factor-α-Induced Inflammatory Signaling and Dysfunction in Vascular Endothelial Cells

Background Hydrogen sulfide (H2S), the third physiologically relevant gaseous molecule, is recognized increasingly as an anti-inflammatory mediator in various inflammatory conditions. Herein, we explored the effects and mechanisms of sodium hydrosulfide (NaHS, a H2S donor) on tumor necrosis factor (TNF)-α-induced human umbilical vein endothelial cells (HUVEC) dysfunction. Methodology and Principal Findings Application of NaHS concentration-dependently suppressed TNF-α-induced mRNA and proteins expressions of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), mRNA expression of P-selectin and E-selectin as well as U937 monocytes adhesion to HUVEC. Western blot analysis revealed that the expression of the cytoprotective enzyme, heme oxygenase-1 (HO-1), was induced and coincident with the anti-inflammatory action of NaHS. Furthermore, TNF-α-induced NF-κB activation assessed by IκBα degradation and p65 phosphorylation and nuclear translocation and ROS production were diminished in cells subjected to treatment with NaHS. Significance H2S can exert an anti-inflammatory effect in endothelial cells through a mechanism that involves the up-regulation of HO-1.

S-Propargyl-cysteine, a novel hydrogen sulfide-modulated agent, attenuates lipopolysaccharide-induced spatial learning and memory impairment: Involvement of TNF signaling and NF-κB pathway in rats

Neuroinflammation exacerbates hyperphosphorylated tau and amyloid-β (Aβ) generation by generating a plethora of inflammatory mediators and neurotoxic compounds in a transgenic model of Alzheimers disease (AD), and it was reported that hydrogen sulfide (H₂S) attenuates lipopolysaccharide (LPS)-induced neuroinflammation both in vitro and in vivo. In the present study, the protective effects of S-propargyl-cysteine (SPRC) on spatial learning and memory impairment induced by LPS were examined in vivo, and the possible mechanisms were explored. The data showed that SPRC administration by intraperitoneal (i.p.) injection may attenuate cognitive impairment induced by bilateral intracerebroventricular (b.i.c.v.) injection of 5 μg of LPS in rats. Subsequently, SPRC prevented a decrease of H₂S levels in rat hippocampus subjected to LPS. Furthermore, SPRC afforded beneficial actions in inhibitions tumor necrosis factor (TNF)-α, TNF-α receptor 1 (TNFR1) and Aβ generation, as well as IκB-α degradation and phospho-transcription factors of the nuclear factor κB p65 (p-NF-κB p65) activation induced by LPS. These findings suggested that SPRC, a novel H₂S-modulated agent, might be a potential agent for the treatment of neuroinflammation-related diseases, such as AD.

Hydrogen sulfide attenuates lipopolysaccharide-induced cognitive impairment: a pro-inflammatory pathway in rats.

The present study investigated the effect of sodium hydrosulfide (NaHS), a H(2)S donor, on cognitive impairment and neuroinflammatory changes induced by bilateral intracerebroventricular injections of LPS at a dose of 10mug/rat. Rats received 5mg/kg NaHS or volume-matched vehicle administration by intraperitoneal injection 3days before LPS injection then for 9days once daily. Morris water maze was used to detect the cognitive function. Compared to the sham-treated rats, LPS injection significantly prolonged the mean escape latency in the navigation test (P<0.05) and shortened the adjusted escape latency by approximately 30% (P<0.05). Meanwhile, LPS injection decreased H(2)S level but increased pro-inflammatory mediators (i.e., TNF-alpha, TNFR1, degradation of IkappaB-alpha and thereafter activation of NF-kappaB) in hippocampus. However, these effects of LPS were significantly ameliorated with NaHS treatment (P<0.05 vs vehicle-treated group). The present data suggest that H(2)S attenuates LPS-induced cognitive impairment through reducing the overproduction of pro-inflammatory mediators via inhibition of NF-kappaB pathways in rats. This study sets the stage for exploring a novel H(2)S releasing agent for preventing or retarding the development or progression of neurological disorders such as Alzheimers disease.

S-Propargyl-cysteine (SPRC) attenuated lipopolysaccharide-induced inflammatory response in H9c2 cells involved in a hydrogen sulfide-dependent mechanism

The present study attempts to investigate the effects of S-propargyl-cysteine (SPRC), a sulfur-containing amino acid, on lipopolysaccharide (LPS)-induced inflammatory response in H9c2 cardiac myocytes. We found that SPRC prevented nuclear factor-κB (NF-κB) activation assessed by NF-κB p65 phosphorylation and IκBα degradation, suppressed LPS-induced extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation and intracellular reactive oxygen species (ROS) production. Furthermore, incubation of H9c2 cells with SPRC induced phosphorylation of Akt in a time- and concentration-dependent manner. In addition, SPRC attenuated LPS-induced mRNA and protein expression of tumor necrosis factor-α (TNF-α), and mRNA expression of intercellular adhesion molecule-1 (ICAM-1) and inducible nitric oxide synthase (iNOS). The effects of SPRC were abolished by cystathionine γ-lyase [CSE-an enzyme that synthesizes hydrogen sulfide (H2S)] inhibitor, dl-propargylglycine (PAG), SPRC-induced Akt phosphorylation and TNF-α release was also abolished by the phosphoinositide 3-kinase (PI3K) inhibitor LY294002. Furthermore, SPRC also increased LPS-induced down-regulation expression of CSE and H2S level in H9c2 cells. PAG abolished SPRC-induced up-regulation of H2S level. Therefore, we concluded that SPRC produced an anti-inflammatory effect in LPS-stimulated H9c2 cells partly through the CSE/H2S pathway by impairing IκBα/NF-κB signaling and by activating PI3K/Akt signaling pathway.

Leonurine protects against tumor necrosis factor-α-mediated inflammation in human umbilical vein endothelial cells

OBJECTIVE Leonurine, a bioactive alkaloid compound in Herba leonuri, has various pharmacological activities, including antioxidant and anti-apoptotic capacities. This study was conducted to test the hypothesis that leonurine was able to attenuate tumor necrosis factor (TNF)-α-induced human umbilical vein endothelial cells (HUVEC) activation and the underlying molecular mechanisms. METHODS Mitogen-activated protein kinases (MAPK) activation, nuclear factor-κB (NF-κB) activation, and inflammatory mediators expression were detected by Western blot or enzyme-liked immunosorbent assay, intracellular reactive oxygen species (ROS) and NF-κB p65 translocation were measured by immunofluorescence, endothelial cell-monocyte interaction was detected by microscope. RESULTS Leonurine inhibited U937 cells adhesion to TNF-α-activated HUVEC in a concentration dependent manner. Treatment with leonurine blocked TNF-α-induced mRNA and protein expression of adhesion molecules (intercellular adhesion molecule-1 and vascular cell adhesion molecule-1), cyclooxygenase-2, and monocyte chemoattractant protein-1 in endothelial cells. In addition, leonurine attenuated TNF-α-induced intracellular ROS production in HUVEC. Furthermore, leonurine also suppressed the TNF-α-activated p38 phosphorylation and IκBα degradation. Subsequently, reduced NF-κB p65 phosphorylation, nuclear translocation, and DNA-binding activity were also observed. CONCLUSIONS Our results demonstrated for the first time that the anti-inflammatory properties of leonurine in endothelial cells, at least in part, through suppression of NF-κB activation, which may have a potential therapeutic use for inflammatory vascular diseases.

A New Hope for Neurodegeneration: Possible Role of Hydrogen Sulfide

For hundreds of years, hydrogen sulfide (H2S) has been known solely as a toxic gas with the smell of rotten eggs. Nevertheless, the notoriety of H2S as a toxic gas is experiencing a transformation, with an increasing amount of research showing that it regulates a range of physiological and pathological processes in mammals. Hence H2S is a physiologically important molecule and has been referred to as the third gaseous mediator alongside nitric oxide and carbon monoxide. This past decade has seen an exponential growth of scientific interest in the physiological and pathological significance of H2S. In particular, in the central nervous system, H2S facilitates long-term potentiation and regulates intracellular calcium concentration and pH level in brain cells. Interestingly, H2S may exert antioxidant, anti-apoptotic, and anti-inflammatory effects which are related to neurodegenerative disorders such as Alzheimers disease (AD), Parkinsons disease (PD), and vascular dementia. Meanwhile, abnormal generation and metabolism of H2S are involved in most of these neurodegenerative disorders. This review presents current knowledge of H2S and its neuroprotective effects in neurodegenerative disorders, with a special emphasis on AD and PD. It is concluded that a H2S-modulated agent will be a new hope for neurodegenerative disorders including AD and PD.

Leonurine (SCM-198) improves cardiac recovery in rat during chronic infarction.

Leonurine, an alkaloid typically found in Herba leonuri, is known to have both antioxidant and cardioprotective properties. In the present study, we investigated the cardioprotective mechanism of leonurine the in vivo rat model of chronic myocardial ischemia and in vitro H9c2 cardiac myocyte model of oxidative stress. Myocardial ischemia was induced by ligating the left anterior descending coronary artery. Rats were divided into sham, myocardial ischemia+saline, and myocardial ischemia+leonurine (15 mg/kg/day). Cardiac function was recorded by catheterization. Apoptosis-related factor vascular endothelial growth factor (VEGF), survivin, Bcl-2 and Bax and pro-survival signaling pathways Akt, hypoxia inducible factor (HIF)-1α were measured by Western blotting or RT-PCR. Our results showed leonurine significantly improved myocardial function as evidenced by the decreased left ventricle end-diastolic pressure and the increased +dP/dt. Interestingly, leonurine increased the phosphorylation of Akt, the protein and gene expression of Bcl-2, but it reduced the protein and gene expression of Bax in vivo. Meanwhile leonurine significantly increased Akt phosphorylation in a concentration-dependent manner in H9c2 cardiac myocyte induced by oxidative stress in vitro, which was abolished by a phosphoinositide 3-kinase (PI3K) inhibitor, LY294002. Furthermore, leonurine not only increased the expression of HIF-1α but also the expression of survivin and VEGF. The results of present study demonstrated, for the first time that leonurine has potent anti-apoptotic effects after chronic myocardial ischemia mediated by activating the PI3K/Akt signaling pathway. Angiogenic mechanisms may be partially responsible for such an effect, which needs to be studied further.

Leonurine (SCM-198) attenuates myocardial fibrotic response via inhibition of NADPH oxidase 4

In our previous studies, we have reported that leonurine, a plant phenolic alkaloid in Herba leonuri, exerted cardioprotective properties in a number of preclinical experiments. Herein, we investigated the roles and the possible mechanisms of leonurine for reducing fibrotic responses in angiotensin II (Ang II)-stimulated primary neonatal rat cardiac fibroblasts and post-myocardial infarction (MI) rats. In in vitro experiments performed in neonatal rat cardiac fibroblasts, leonurine (10-20 μM) pretreatment attenuated Ang II-induced activation of extracellular signal-regulated kinase 1/2, production of intracellular reactive oxygen species (ROS), expression and activity of matrix metalloproteinase (MMP)-2/9, and expression of α-smooth muscle actin and types I and III collagen. A small interfering RNA-mediated knockdown strategy for NADPH oxidase 4 (Nox4) revealed that Nox4 was required for Ang II-induced activation of cardiac fibroblasts. In vivo studies using a post-MI model in rats indicated that administration of leonurine inhibited myocardial fibrosis while reducing cardiac Nox4 expression, ROS production, NF-κB activation, and plasma MMP-2 activity. In conclusion, our results provide the first evidence that leonurine could prevent cardiac fibrosis and the activation of cardiac fibroblasts partly through modulation of a Nox4-ROS pathway.

A novel compound derived from danshensu inhibits apoptosis via upregulation of heme oxygenase-1 expression in SH-SY5Y cells

BACKGROUND Heme oxygenase-1 (HO-1) has potential anti-apoptotic properties. A novel compound [4-(2-acetoxy-3-((R)-3-(benzylthio)-1-methoxy-1-oxopropan-2- ylamino)-3-oxopropyl)-1,2-phenylene diacetate (DSC)] was synthesized by joining danshensu and cysteine through an appropriate linker. This study investigated if the cytoprotective properties of DSC involved the induction of HO-1. METHODS We evaluated the cytoprotective effects of DSC on H2O2-induced cell damage, apoptosis, intracellular and mitochondrial reactive oxygen species (ROS) production, mitochondrial membrane potential (ΔΨm) loss, and apoptosis-related proteins expression and its underlying mechanisms. RESULTS DSC concentration-dependently attenuated cell death, lactate dehydrogenase release, intracellular and mitochondrial ROS production, and ΔΨm collapse, modulated apoptosis-related proteins (Bcl-2, Bax, caspase-3, p53, and cleaved PARP) expression, and inhibited phosphorylation of extracellular signal-regulated kinase 1/2 in SH-SY5Y cells induced by H2O2. In addition, DSC concentration-dependently induced HO-1 expression associated with nuclear translocation of nuclear factor-erythroid 2 related factor 2 (Nrf-2), while the effect of DSC was inhibited by a phosphoinositide 3-kinase (PI3K) inhibitor LY294002. Furthermore, the protective effect of DSC on H2O2-induced cell death was abolished by HO-1 inhibitor ZnPP, but was mimicked by carbon monoxide-releasing moiety CORM-3 or HO-1 by-product bilirubin. Finally, DSC inhibited H2O2-induced changes of Bcl-2, Bax, and caspase-3 expression, and all of these effects were reversed by HO-1 silencing. CONCLUSIONS Induction of HO-1 may be, at least in part, responsible for the anti-apoptotic property of DSC, an effect that involved the activation of PI3K/Akt/Nrf-2 axis. GENERAL SIGNIFICANCE DSC might have the potential for beneficial therapeutic interventions for neurodegenerative diseases.