-
[show abstract]
[hide abstract]
ABSTRACT: Sevoflurane is a potent non-toxic inducer of the hepatoprotective enzyme heme oxygenase-1 (HO-1). So far, little is known about the underlying molecular mechanism. Therefore the aim of this study was to characterize the respective signal transduction pathway and in particular to elucidate the role of Kupffer cells in this context. Rats were treated with or without sevoflurane. The effects on hepatic HO-1 gene expression, mitogen-activated protein kinases and transcription factors were studied by Northern and Western blot analyses, immunostaining, electrophoretic mobility shift assays, and enzymatic activity assays. Kupffer cells were depleted by administration of clodronate liposomes in vivo to characterize their role in HO-1 signal transduction. In additional in vitro experiments, HO-1 mRNA expression in primary rat hepatocytes and HepG2 cells was assessed. Sevoflurane up-regulated HO-1 gene expression in pericentral hepatocytes and increased HO enzyme activity in vivo. This was associated with activation of ERK1/2 and activator protein-1. We identified c-jun/AP-1, JunD, c-fos, and Fra-1 as active subunits of the activator protein-1 complex. Administration of clodronate liposomes to rats led to depletion of Kupffer cells without affecting sevoflurane induced HO-1 expression. Moreover, sevoflurane up-regulated HO-1 mRNA in primary rat hepatocytes but not in HepG2 cells. Our results suggest that sevoflurane induced HO-1 gene expression in pericentral hepatocytes does not depend on Kupffer cells and is associated with activation of ERK1/2 and activator protein-1. Since we could recently demonstrate significant hepatoprotective effects of HO-1 induced by isoflurane, the present results may help to establish new concepts in hepatic organ protection.
The international journal of biochemistry & cell biology 11/2010; 42(11):1876-83. · 4.89 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Pulmonary dysfunction presumably linked to an inflammatory response is frequent after cardiac operations using cardiopulmonary bypass (CPB) and pulmonary hypoperfusion. We previously demonstrated that active perfusion of the lungs during CPB reduces ischemic lung injury. We now hypothesized that avoiding ischemia of the lungs during CPB by active pulmonary perfusion would decrease pulmonary inflammatory response.
Pigs were randomized to a control group with CPB for 120 minutes, followed by 120 minutes of postbypass reperfusion, or to the study groups where animals underwent active pulmonary perfusion with pulsatile or nonpulsatile perfusion during CPB (n = 7 in each group). Activation of transcription factor activity (nuclear factor [NF]-kappaB and activating protein [AP]-1) was determined by electrophoretic mobility shift assay. Levels of proinflammatory protein expression (interleukin [IL]-1, IL-6, and tumor necrosis factor [TNF]-alpha) were quantified by enzyme-linked immunoabsorbent assay. Caspase-3 activity was measured using a fluorogenic assay.
The activation of transcription factor AP-1 and NF-kappaB was reduced in the pulsatile pulmonary perfusion group. The caspase-3 activity and the expression of IL-1, IL-6, and TNF-alpha revealed a significant decrease in the pulsatile and nonpulsatile pulmonary perfusion groups. Animals of the pulsatile pulmonary perfusion group showed significantly reduced IL-6 expression and caspase-3 activity compared with the nonpulsatile pulmonary perfusion group.
Active pulmonary perfusion reduces the inflammatory response and apoptosis in the lungs observed during conventional CPB. This effect is greatest when pulmonary perfusion is performed with pulsatility. The reduction in cytokine expression by pulsatile pulmonary perfusion might be mediated by AP-1 and NF-kappaB.
The Annals of thoracic surgery 08/2008; 86(1):115-22. · 3.74 Impact Factor
-
Matjaz Humar,
Hannah Dohrmann, Philipp Stein,
Nikolaos Andriopoulos,
Ulrich Goebel,
Martin Roesslein,
Rene Schmidt,
Christian I Schwer,
Torsten Loop,
Klaus K Geiger,
Heike L Pahl,
Benedikt H J Pannen
[show abstract]
[hide abstract]
ABSTRACT: Thionamides, inhibitors of the thyroid peroxidase-mediated iodination, are clinically used in the treatment of hyperthyroidism. However, the use of antithyroid drugs is associated with immunomodulatory effects, and recent studies with thionamide-related heterocyclic thioderivates demonstrated direct anti-inflammatory and immunosuppressive properties. Using primary human T-lymphocytes, we show that the heterocyclic thionamides carbimazole and propylthiouracil inhibit synthesis of the proinflammatory cytokines tumor necrosis factor (TNF)alpha and interferon (IFN)gamma. In addition, DNA binding of nuclear factor (NF)-kappaB, a proinflammatory transcription factor that regulates both TNFalpha and IFNgamma synthesis, and NF-kappaB-dependent reporter gene expression were reduced. Abrogation of NF-kappaB activity was accompanied by reduced phosphorylation and proteolytic degradation of inhibitor of kappaB (IkappaB)alpha, the inhibitory subunit of the NF-kappaB complex. Carbimazole inhibited NF-kappaB via the small GTPase Rac-1, whereas propylthiouracil inhibited the phosphorylation of IkappaBalpha by its kinase inhibitor of kappaB kinase alpha. Methimazole had no effect on NF-kappaB induction, demonstrating that drug potency correlated with the chemical reactivity of the thionamide-associated sulfur group. Taken together, our data demonstrate that thioureylenes with a common, heterocyclic structure inhibit inflammation and immune function via the NF-kappaB pathway. Our results may explain the observed remission of proinflammatory diseases upon antithyroid therapy in hyperthyroid patients. The use of related thioureylenes may provide a new therapeutic basis for the development and application of anti-inflammatory compounds.
Journal of Pharmacology and Experimental Therapeutics 04/2008; 324(3):1037-44. · 3.83 Impact Factor
-
Matjaz Humar,
Hannah Dohrmann, Philipp Stein,
Nikolaos Andriopoulos,
Ulrich Goebel,
Bernd Heimrich,
Martin Roesslein,
Rene Schmidt,
Christian I Schwer,
Alexander Hoetzel,
Torsten Loop,
Heike L Pahl,
Klaus K Geiger,
Benedikt H J Pannen
[show abstract]
[hide abstract]
ABSTRACT: Treatment of hyperthyroidism by thionamides is associated with immunomodulatory effects, but the mechanism of thionamide-induced immunosuppression is unclear. Here we show that thionamides directly inhibit interleukin-2 cytokine expression, proliferation, and the activation (CD69 expression) of primary human T lymphocytes. Inhibition of immune function was associated with a repression of DNA binding of the cooperatively acting immunoregulatory transcription factors activator protein 1 (AP-1) and nuclear factor of activated T-cells (NFAT). Likewise, thionamides block the GTPase p21Ras, the mitogen-activated protein kinases, and impair the calcineurin/calmodulin-dependent NFAT dephosphorylation and nuclear translocation. The potency of inhibition correlated with the chemical reactivity of the thionamide-associated sulfur group. Taken together, our data demonstrate that thio-derivates with a common heterocyclic thioureylene-structure mediate a direct suppression of immune functions in T-cells via inhibition of the AP-1/NFAT pathway. Our observations may also explain the clinical and pathological resolution of some secondary, calcineurin, and mitogen-activated protein kinase-associated diseases upon thionamide treatment in hyperthyroid patients. This offers a new therapeutic basis for the development and application of heterocyclic thio-derivates.
Molecular pharmacology 01/2008; 72(6):1647-56. · 4.53 Impact Factor
