Effect of hydrogen sulfide on the phosphatidylinositol 3-kinase-protein kinase B pathway and on caerulein-induced cytokine production in isolated mouse pancreatic acinar cells.
ABSTRACT We have shown earlier that mouse pancreatic acinar cells produce hydrogen sulfide (H(2)S) and play a role in the pathogenesis of acute pancreatitis. It is noteworthy that recent evidence indicates that H(2)S has anti-inflammatory effects. To date, the mechanism by which H(2)S directly reduces inflammation has not been elucidated. In the present study, we hypothesized that H(2)S inhibits the production of proinflammatory cytokines by activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) pathway. Pancreatic acinar cells were treated with the H(2)S donor, sodium hydrogen sulfide (NaHS) (5, 10, and 30 microM). To better understand the effect of H(2)S in inflammation, pancreatic acinar cells were stimulated with caerulein after the addition of NaHS (5, 10, and 30 microM). We observed that H(2)S at the 5 microM concentration down-regulates the activation of NF-kappaB and degradation of IkappaB alpha. However, H(2)S (5 microM) activates PI3K as reflected by AKT phosphorylation. We found that H(2)S-mediated activation of PI3K in caerulein-treated acinar cells correlated with the down-regulation of extracellular signal-regulated kinase 1/2 phosphorylation, whereas phosphorylation of p38 and c-Jun NH(2)-terminal kinase and mitogen-activated protein kinases was unchanged. The PI3K inhibitor LY294002 [2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride] abolished the H(2)S-mediated activation of AKT and increases tumor necrosis factor alpha and interleukin 1beta levels in caerulein-treated acinar cells. These findings indicate that the phosphatidylinositol 3-kinase plays a negative role in NaHS-treated pancreatic acinar cells and suggest a role for H(2)S in the PI3K/AKT pathway in acute pancreatitis.
- SourceAvailable from: ncbi.nlm.nih.gov[Show abstract] [Hide abstract]
ABSTRACT: Hydrogen sulphide (H(2)S) is a novel neuromodulator. The present study aimed to investigate the protective effect of H(2)S against cell injury induced by 6-hydroxydopamine (6-OHDA), a selective dopaminergic neurotoxin often used to establish a model of Parkinson's disease for studying the underlying mechanisms of this condition. Cell viability in SH-SY5Y cells was measured using MTT assay. Western blot analysis and pharmacological manipulation were employed to study the signalling mechanisms. Treatment of SH-SY5Y cells with 6-OHDA (50-200 microM) for 12 h decreased cell viability. Exogenous application of NaHS (an H(2)S donor, 100-1000 microM) or overexpression of cystathionine beta-synthase (a predominant enzyme to produce endogenous H(2)S in SH-SY5Y cells) protected cells against 6-OHDA-induced cell apoptosis and death. Furthermore, NaHS reversed 6-OHDA-induced loss of tyrosine hydroxylase. Western blot analysis showed that NaHS reversed the down-regulation of PKCalpha, epsilon and Akt and the up-regulation of PKCdelta in 6-OHDA-treated cells. Blockade of PKCalpha with Gö6976 (2 microM), PKCepsilon with EAVSLKPT (200 microM) or PI3K with LY294002 (20 microM) reduced the protective effects of H(2)S. However, inhibition of PKCdelta with rottlerin (5 microM) failed to affect 6-OHDA-induced cell injury. These data suggest that the protective effects of NaHS mainly resulted from activation of PKCalpha, epsilon and PI3K/Akt pathway. In addition, NaHS-induced Akt phosphorylation was significantly attenuated by Gö6976 and EAVSLKPT, suggesting that the activation of Akt by NaHS is PKCalpha, epsilon-dependent. H(2)S protects SH-SY5Y cells against 6-OHDA-induced cell injury by activating the PKCalpha, epsilon/PI3K/Akt pathway.British Journal of Pharmacology 09/2010; 161(2):467-80. · 5.07 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Hydrogen sulfide (H2S) is a well-known toxic gas that is synthesized in the human body from the amino acids cystathionine, homocysteine, and cysteine by the action of at least two distinct enzymes: cystathionine-γ-lyase and cystathionine-β-synthase. In the past few years, H2S has emerged as a novel and increasingly important biological mediator. Imbalances in H2S have also been shown to be associated with various disease conditions. However, defining the precise pathophysiology of H2S is proving to be a complex challenge. Recent research in our laboratory has shown H2S as a novel mediator of inflammation and work in several groups worldwide is currently focused on determining the role of H2S in inflammation. H2S has been implicated in different inflammatory conditions, such as acute pancreatitis, sepsis, joint inflammation, and chronic obstructive pulmonary disease (COPD). Active research on the role of H2S in inflammation will unravel the pathophysiology of its actions in inflammatory conditions and may help develop novel therapeutic approaches for several, as yet incurable, disease conditions.Scientifica. 01/2012; 2012:159680.
- [Show abstract] [Hide abstract]
ABSTRACT: Reactive oxygen radicals, pro-inflammatory mediators and cytokines have been implicated in caerulein induced acute pancreatitis. Nordihydroguaiaretic acid (NDGA), a plant lignin, has marked anti-inflammatory properties. The present study aimed to investigate the possible protective effect of NDGA against caerulein induced pancreatitis. Acute pancreatitis was induced by intraperitoneal administration of eight doses of caerulein in male swiss albino mice. NDGA was administered after 9 h of acute pancreatitis induction. Pancreatic damage and the protective effect of NDGA were assessed by oxidative stress parameters and histopathology of pancreas. The mRNA expression of heat shock proteins (DNAJ C15 and HSPD1) was examined by real-time RT-PCR analysis. Expression of HSP 27, NF-κB, TNF-α, p-p38, Bcl-2, p-PP2A, procaspase-3, caspase-3 and histone modifications were examined by western blotting. NDGA attenuated the oxidative stress, led to increased plasma α-amylase and decreased IGF-1 in AP mice. It modulated the mRNA and protein levels of heat shock proteins and reduced the expression of NF-κB, TNF-α and p-p38. It increased the number of TUNEL positive apoptotic cells in the pancreas of AP mice. In addition, NDGA prevented the changes in modifications of histone H3 in acute pancreatitis. To best of our knowledge, this is the first report which suggests that NDGA prevents the progression of acute pancreatitis by involving alteration of histone H3 modifications and modulating the expression of genes involved in inflammatory/apoptotic cascade, which may be responsible for decreased necrosis and increased apoptosis in this model of acute pancreatitis.Apoptosis 08/2011; 16(11):1138-49. · 4.07 Impact Factor