Sang-Wan Seo

Genistein protects pancreatic β cells against cytokine-mediated toxicity

In the past few decades, the use of genistein as an anti-inflammatory agent has gained much attention. Our current study focuses on the preventive effects of genistein on cytokine-induced pancreatic beta-cell damage. Treatment of RINm5F (RIN) rat insulinoma cells with interleukin (IL)-1beta and interferon (IFN)-gamma induced cell damage, which was correlated with nitric oxide (NO) production. Genistein completely prevented cytokine-mediated cytotoxicity and NO production, a finding that correlated well with reduced levels of the inducible form of NO synthase (iNOS) mRNA and protein. The molecular mechanism of genistein inhibition of iNOS gene expression appeared to involve the inhibition of NFkappaB activation. The cytokine induced increases in NFkappaB binding activity, nuclear p50 and p65 subunit levels, and IkappaBalpha degradation in cytosol compared to unstimulated cells; genistein abolished all of these parameters. The cytoprotective effects of genistein are also mediated through the suppression of ERK-1/2 and Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathways. In a second set of experiments, rat islets were used. The findings on beta-cell protective effects of genistein were essentially the same as for the RIN cell data, namely genistein prevented cytokine-induced NO production, iNOS expression, ERK-1/2 activation, JAK/STAT activation, and impairment of glucose-stimulated insulin secretion. Collectively, these results suggest that genistein might be used to preserve functional beta-cell mass.

Inhibition of lipopolysaccharide-induced inflammatory responses by piperine.

Piperine, a main component of Piper longum Linn. and Piper nigrum Linn., is a plant alkaloid with a long history of medical use. Piperine exhibits anti-inflammatory activity; however, the underlying mechanism remains unknown. We examined the effects of piperine on lipopolysaccharide (LPS)-induced inflammatory responses. Administration of piperine inhibited LPS-induced endotoxin shock, leukocyte accumulation and the production of tumor necrosis factor-alpha (TNF-alpha), but not of interleukin (IL)-1beta and IL-6. In peritoneal macrophages, piperine inhibited LPS/poly (I:C)/CpG-ODN-induced TNF-alpha production. Piperine also inhibited LPS-induced endotoxin shock in TNF-alpha knockout (KO) mice. To clarify the inhibitory mechanism of LPS-induced endotoxin shock, type 1 interferon (IFN) mRNA expression was determined. Piperine inhibited LPS-induced expression of type 1 IFN mRNA. Piperine inhibited the levels of interferon regulatory factor (IRF)-1 and IRF-7 mRNA, and the phosphorylation and nuclear translocation of IRF-3. Piperine also reduced activation of signal transducer and activator of transcription (STAT)-1. In addition, activation of STAT-1 was inhibited in IFN-alpha/beta-treated cells by piperine. These results suggest that piperine inhibits LPS-induced endotoxin shock through inhibition of type 1 IFN production.

Mechanical Stress Activates Proinflammatory Cytokines and Antioxidant Defense Enzymes in Human Dental Pulp Cells

This study was conducted to investigate the effects of mechanical stress, particularly cyclic strain, on proinflammatory cytokines as well as antioxidant properties and their interactions with cellular defense systems in human dental pulp (HDP) cells. Exposure of HDP cells to mechanical strain induced inflammatory cytokines such as interleukin-1 beta, tumor necrosis factor-alpha, and interleukin-6, as well as antioxidant genes such as heme oxygenase-1, superoxide dismutases, reduced nicotinamide adenine dinucleotide phosphate quinone oxidoreductase-1, and glutathione peroxidases. In addition, treatment with N-acetylcysteine, indomethacin, and heme oxygenase-1 inhibitors blocked reactive oxygen species production, antioxidant response element (ARE) gene expression, and Nrf2 accumulation that occurred in response to mechanical stress. These data demonstrate that mechanical strain activates inflammatory cytokines and oxidative stress, which then act in concert to induce the Nrf2-/ARE-mediated antioxidant enzymes. Therefore, we suggest that the activation of a compensatory adaptation or defense antioxidant system might represent a novel mechanism for protecting HDP cells against mechanical stress.

Selective GSK-3β inhibitors attenuate the cisplatin-induced cytotoxicity of auditory cells

Glycogen synthase kinase-3 (GSK-3) plays an important role in the regulation of apoptosis. However, the role of GSK-3 in the auditory system remains unknown. Here we examined whether the GSK-3-specific inhibitors, SB 216763 and LiCl, could protect against cisplatin-induced cytotoxicity of auditory cells. GSK-3 was activated by cisplatin treatment of HEI-OC1 cells. SB 216763 or LiCl treatments inhibited cisplatin-induced apoptosis in a dose-dependent manner and activated caspase-9, -8 and -3. In rat primary explants of the organ of Corti, SB 216763 or LiCl treatments completely abrogated the cisplatin-induced destruction of outer hair cell arrays. Administration of SB 216763 or LiCl inhibited cochlear destruction and the production of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and IL-6 in cisplatin-injected mice. Furthermore, administration of SB 216763 or LiCl reduced the thresholds of the auditory brainstem response (ABR) in cisplatin-injected mice. Collectively, these results suggest that cisplatin-induced ototoxicity might be associated with modulation of GSK-3 activation.

Effects of bee venom on cholecystokinin octapeptide-induced acute pancreatitis in rats.

Objectives: Bee venom (BV) has frequently been used as a remedy for inflammatory diseases. The aim of this study was to investigate the effect of BV on cholecystokinin octapeptide (CCK-8)-induced acute pancreatitis (AP) in rats. Methods: The BV pretreatment group: 0.25 mg/kg BV was administered subcutaneously, followed by 75 &mgr;g/kg CCK-8 subcutaneously 3 times after 1, 3, and 5 hours. This whole procedure was repeated for 5 days. Control group: CCK-8 subcutaneously 3 times after 1, 3, and 5 hours for 5 days. The BV posttreatment group: CCK-8 subcutaneously 3 times at an interval of 2 hours for 3 days, and then 0.25 mg/kg of BV was administered subcutaneously. Control group: CCK-8 subcutaneously 3 times at an interval of 2 hours for 3 days. Results: The BV pretreatment and posttreatment ameliorated many of the examined laboratory parameters (the pancreatic weight [PW]/body weight [BW] ratio, the serum amylase and lipase activity) and reduced histological damages in pancreas. Furthermore, BV pretreatment reduced the production of tumor necrosis factor-&agr;, interleukin 1, and interleukin 6 and also decreased pancreatic nuclearfactor-&kgr;B binding activity compared with saline-treated group in the AP model. The BV also increased heat shock protein 60 (HSP60) and heat shock protein 72 (HSP72) compared with the saline-treated group in the AP model. Conclusions: These findings suggest that the anti-inflammatory effect of BV in CCK-8-induced AP seems to be mediated by inhibiting nuclear factor-&kgr;B binding activity, and that BV may have a protective effect against AP.

Effect of biologically active fraction of Nardostachys jatamansi on cerulein-induced acute pancreatitis

AIM To determine if the fraction of Nardostachys jatamansi (NJ) has the potential to ameliorate the severity of acute pancreatitis (AP). METHODS Mice were administered the biologically active fraction of NJ, i.e., the 4th fraction (NJ4), intraperitoneally, and then injected with the stable cholecystokinin analogue cerulein hourly for 6 h. Six hours after the last cerulein injection, the pancreas, lung, and blood were harvested for morphological examination, measurement of cytokine expression, and examination of neutrophil infiltration. RESULTS NJ4 administration attenuated the severity of AP and lung injury associated with AP. It also reduced cytokine production and neutrophil infiltration and resulted in the in vivo up-regulation of heme oxygenase-1 (HO-1). Furthermore, NJ4 and its biologically active fraction, NJ4-2 inhibited the cerulein-induced death of acinar cells by inducing HO-1 in isolated pancreatic acinar cells. CONCLUSION These results suggest that NJ4 may be a candidate fraction offering protection in AP and NJ4 might ameliorate the severity of pancreatitis by inducing HO-1 expression.

Protective effects of Curcuma longa against cerulein-induced acute pancreatitis and pancreatitis-associated lung injury.

Curcuma longa (CL) has been reported to possess a variety of pharmacological activities. However, the effects of CL on acute pancreatitis (AP) have not yet been determined. To this end, we examined the effects of CL on cerulein-induced AP. Cell viability and cytokine productions were measured in pancreatic acini. Mice were divided into 3 groups: i) Normal group, ii) normal saline-treated group, iii) group treated with CL at a dose of 0.05, 0.1, 0.5 and 1 g/kg. CL was administered orally to mice for 7 days. The mice were intraperitoneally injected with the stable cholecystokinin analogue, cerulein (50 μg/kg), every hour for a total of 6 h. The mice were sacrificed 6 h after the completion of the cerulein injections. Blood samples were obtained to determine serum amylase, lipase and cytokine levels. The pancreas was rapidly removed for morphological examination, measurement of tissue myeloperoxidase activity, as well as the level of cytokines and heme oxygenase-1 (HO-1). The CL treatment reduced cerulein-induced cell death and cytokine production in pancreatic acini. The administration of CL significantly ameliorated the severity of pancreatitis and pancreatitis-associated lung injury, as was shown by the reduction in pancreatic edema, neutrophil infiltration, vacuolization, necrosis, serum amylase, lipase and cytokine levels, and mRNA expression of multiple inflammatory mediators such as interleukin (IL)-1ß and -6 and tumor necrosis factor (TNF)-α. In order to identify the regulatory mechanism of CL on cerulein-induced pancreatitis, we examined the level of HO-1 in the pancreas. We found that the administration of CL induced HO-1. Our results suggest that CL plays a protective role in the development of AP and pancreatitis-associated lung injury.

Myrrh Inhibits LPS-Induced Inflammatory Response and Protects from Cecal Ligation and Puncture-Induced Sepsis

Myrrh has been used as an antibacterial and anti-inflammatory agent. However, effect of myrrh on peritoneal macrophages and clinically relevant models of septic shock, such as cecal ligation and puncture (CLP), is not well understood. Here, we investigated the inhibitory effect and mechanism(s) of myrrh on inflammatory responses. Myrrh inhibited LPS-induced productions of inflammatory mediators such as nitric oxide, prostaglandin E2, and tumor necrosis factor-α but not of interleukin (IL)-1β and IL-6 in peritoneal macrophages. In addition, Myrrh inhibited LPS-induced activation of c-jun NH2-terminal kinase (JNK) but not of extracellular signal-regulated kinase (ERK), p38, and nuclear factor-κB. Administration of Myrrh reduced the CLP-induced mortality and bacterial counts and inhibited inflammatory mediators. Furthermore, administration of Myrrh attenuated CLP-induced liver damages, which were mainly evidenced by decreased infiltration of leukocytes and aspartate aminotransferase/alanine aminotransferase level. Taken together, these results provide the evidence for the anti-inflammatory and antibacterial potential of Myrrh in sepsis.

Melittin inhibits cerulein-induced acute pancreatitis via inhibition of the JNK pathway

The major compound of bee venom, melittin, has been used as an anti-inflammatory reagent for decades. However, the potential of melittin to ameliorate acute pancreatitis (AP) is unknown. Our aim was to investigate the effect of melittin on cerulein-induced AP. Pre- and post-treatment with melittin inhibited histological changes in the pancreas and lungs during cerulein-induced AP. Pancreatic weight/body weight ratios; digestive enzymes, including amylase and lipase; serum and pancreatic cytokine expression; and myeloperoxidase activity were decreased. In addition, treatment with melittin inhibited the activation of c-Jun NH(2)-terminal protein kinase (JNK) in the pancreas during cerulein-induced pancreatitis. In accordance with the results of in vivo experiments, melittin reduced cerulein-induced cell death, and production of inflammatory cytokines. In conclusion, our results suggest that melittin attenuated AP and AP-associated lung injury through the inhibition of JNK activation.