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Recent studies suggest that the skeletal muscle may be a significant site of IL-6 production in various conditions, including exercise, inflammation, hypoperfusion, denervation, and local muscle injury. The mediators and molecular mechanisms regulating muscle IL-6 production are poorly understood. We tested the hypothesis that IL-6 production in muscle cells is regulated by IL-1[beta] and that mitogen-activated protein (MAP) kinase signaling and NF-[kappa]B activation are involved in IL-1[beta]-induced IL-6 production. Cultured C2C12 cells, a mouse skeletal muscle cell line, were treated with different concentrations (0.1-2 ng/ml) of IL-1[beta] in the absence or presence of the p38 MAP kinase inhibitor SB-208350 or the p42/44 inhibitor PD-98059. Protein and gene expression of IL-6 were determined by ELISA and real-time PCR, respectively. NF-[kappa]B DNA binding activity was determined by electrophoretic mobility shift assay and by transfecting myocytes with a luciferase reporter plasmid containing a promoter construct with multiple repeats of NF-[kappa]B binding site. Treatment of myotubes with IL-1[beta] resulted in a dose- and time-dependent increase of IL-6 production accompanied by an ~25-fold increase in IL-6 mRNA levels. IL-1[beta] stimulated NF-[kappa]B DNA binding activity and gene activation. SB-208350 and PD-98059 inhibited the increase in IL-6 production induced by IL-1[beta]. The present results support the concept that skeletal muscle is an important site of IL-6 production. In addition, the results suggest the IL-1[beta] regulates muscle IL-6 production at least in part by activating the MAP kinase pathway and NF-[kappa]B. interleukin-6 production; cytokines; mitogen-activated protein kinase; nuclear factor-[kappa]B

Mucosal and enterocyte IL-6 production is increased during sepsis and endotoxemia. Recent studies suggest that cAMP potentiates IL-6 production in endotoxin- or IL-[beta]-stimulated enterocytes, but the molecular mechanisms are not known. We examined the role of the transcription factors NF-[kappa]B, activator protein (AP)-I, CCAAT/enhancer binding protein (C/ EBP), and cAMP response element-binding protein (CREB) in cAMP-induced IL-6 production in cultured Caco-2 cells, a human intestinal epithelial cell line. In addition, the role of the protein kinase A (PKA), protein kinase C (PKC), and mitogen-activated protein (MAP) kinase signaling pathways was examined. Treatment of the cells with IL-[beta] increased IL-6 production and activated the IL-6 promoter in cells transfected with a luciferase reporter plasmid containing a wild-type IL-6 promoter. These effects of IL-[beta] were significantly potentiated by cAMP. When the binding sites for the individual transcription factors in the IL-6 promoter were mutated, results indicated that all four transcription factors may be involved in the cAMP-induced activation of the IL-6 gene. Treatment of the Caco-2 cells with cAMP increased the DNA binding activity of CREB, C/EBP, and AP-1, but not NF-[kappa]B. By using specific blockers, evidence was found that both PKA and p38 MAP kinase (but not PKC or p42/44 MAP kinase) may be involved in the cAMP-induced potentiation of IL-6 production. The present results suggest that cAMP activates multiple transcription factors involved in the regulation of the IL-6 gene and that the activation of these transcription factors may at least in part explain why cAMP potentiates IL-6 production in stimulated enterocytes. mucosa; inflammation; cytokines; mitogen-activated protein kinase

Abstract Background The management of penetrating abdominal stab wounds has been the subject of continued reappraisal and controversy. In the present study a novel method which combines the use of diagnostic laparoscopy and DPL, termed laparoscopic diagnostic peritoneal lavage (L-DPL) is described Method Five trauma patients with penetrating injuries to the lower chest or abdomen were included. Standard videoscopic equipment is utilized for the laparoscopic trauma evaluation of the injured patient. When no significant injury is detected, the videoscope is withdrawn and 1000 mL of normal saline is infused through the abdominal trochar into the peritoneal cavity, and the effluent fluid studied for RBCs, WBC, amylase debry, bile as it is uced in regular diagnostic peritoneal lavage Results Laparoscopic peritoneal lavage (L-DPL) was then performed and proved to be negative in all 5 patients. RBC lavage counts above 100,000/mcrl were not considered as a positive lavage result, because the bleeding source was directly observed and controlled laparoscopically. All patients recovered uneventfully and were released within 3 days. This procedure combines the visual advantages of laparoscopy together with the sensitivity and specificty of DPL for the diagnosis of significant penetrating intra-abdominal injury, when the diagnostic strategy of selective consevatism for abdominal stab wounds is adopted. Conclusion A method of laparoscopic diagnostic peritoneal lavage (L-DPL) in hemodynamically stable patients with penetrating lower thoracic or abdominal stab wounds is described. The method is especially applicable for trauma surgeons with only basic experience in laparoscopic technique. This procedure is used to obtain conclusive evidence of significant intra-abdominal injury, confirm peritoneal penetration, control intra-abdominal bleeding, and repair lacerations to the diaphragm and abdominal wall. The combination of laparoscopy and DPL afforded by the L-DPL method adds to the sensitivity and specificity of DPL, and avoids under or over sesitivty, that have limited the use of DPL in the hemodynamically stable trauma patients with suspicious or proven peritoneal penetration.

In previous studies, the heat shock response, induced by hyperthermia or sodium arsenite, increased interleukin (IL)-6 production in intestinal mucosa and cultured human enterocytes. A novel way to induce the heat shock response, documented in other cell types, is treatment with proteasome inhibitors. It is not known if proteasome inhibition induces heat shock in enterocytes or influences IL-6 production. Here we tested the hypothesis that treatment of cultured Caco-2 cells, a human intestinal epithelial cell line, with proteasome inhibitors induces the heat shock response and stimulates IL-6 production. Treatment of Caco-2 cells with one of the proteasome inhibitors MG-132 or lactacystin activated the transcription factor heat shock factors (HSF)-1 and -2 and upregulated cellular levels of the 72-kDa heat shock protein HSP-72. The same treatment resulted in increased gene and protein expression of IL-6, a response that was blocked by quercetin. Additional experiments revealed that the IL-6 gene promoter contains a HSF-responsive element and that the IL-6 gene may be regulated by the heat shock response. The present results suggest that proteasome inhibition induces heat shock response and IL-6 production in enterocytes and that IL-6 may be a heat shock-responsive gene, at least under certain circumstances. The observations are important considering the multiple biological roles of IL-6, both locally in the gut mucosa and systemically, and considering recent proposals in the literature to use proteasome inhibitors in the clinical setting to induce the heat shock response. intestine; mucosa; enterocyte; stress response; cytokine