Induction of Interleukin-1β mRNA in Rat Brain After Transient Forebrain Ischemia

The expression of interleukin-1 beta (IL-1 beta) mRNA in the cerebral cortex, hippocampus, striatum, and thalamus of rats was studied after transient forebrain ischemia. IL-1 beta mRNA was not detected in all these regions of sham-operated control rats. IL-1 beta mRNA was induced after transient forebrain ischemia and reached a detectable level in all regions examined 15 min after the start of recirculation. The induction of IL-1 beta mRNA had a few peaks, that is, peaks were observed at 30 and 240 min in the four regions examined, and another peak was observed at 90 min in the striatum. One day after the start of recirculation, IL-1 beta mRNA levels were markedly decreased, but even 7 days after that, IL-1 beta mRNA was found at very low levels in all regions examined. The amounts of c-fos and beta-actin mRNAs on the same blots were also examined. The induction of c-fos mRNA was transient and had only one peak in all regions examined, whereas the levels of beta-actin mRNA in these regions were fairly constant throughout the recirculation period. Thus, we provide the first evidence for a characteristic expression of IL-1 beta mRNA in several brain regions after transient forebrain ischemia.     

Interleukin-1beta induces sialyl Lewis X on hepatocellular carcinoma HuH-7 cells via enhanced expression of ST3Gal IV and FUT VI gene

We previously demonstrated that human hepatocellular carcinoma-derived HuH-7 cells stimulated with interleukin-1beta (IL-1beta) produce alpha(1)-acid glycoprotein (AGP) with increased amounts of sialyl Lewis X (sLeX) antigen, although the mechanism remained obscure. Here, we report our investigation of the mechanism. sLeX expression on HuH-7 cells was induced 2.5 times more after 48 h stimulation with 100 U/mL IL-1 beta compared with control, as indicated by anti-sLeX antibody binding. Furthermore, expression of 2,3-sialylated N-acetyllactosamine increased gradually up to 48 h after IL-1 beta stimulation; this preceded the increase in sLeX expression. Increases in alpha 2,3-sialyltransferase activity also preceded increases in alpha1,3-fucosyltransferase activity. Furthermore, mRNA levels of ST3Gal IV, FUT IV and VI in HuH-7 cells stimulated with IL- 1beta were increased at 2-4 h, while increases in FUT VI mRNA level occurred gradually after 24 h. IL-1 beta-induced sLeX expression on HuH-7 cells was suppressed by transfection of gene-specific small interference RNAs against FUT VI and ST3Gal IV but not against FUT IV and ST3Gal III. These data results that IL-1 beta induces expression of sLeX on HuH-7 cells by enhanced expression of FUT VI and ST3Gal IV gene.     

Interleukin-1beta induces the expression of aquaporin-4 through a nuclear factor-kappaB pathway in rat astrocytes

Interleukin (IL)-1beta is known to play a role in the formation of brain edema after various types of injury. Aquaporin (AQP)4 is also reported to be involved in the progression of brain edema. We tested the hypothesis that AQP4 is induced in response to IL-1beta. We found that expression of AQP4 mRNA and protein was significantly up-regulated by IL-1beta in cultured rat astrocytes, and that intracerebroventricular administration of IL-1beta increased the expression of AQP4 protein in rat brain. The effects of IL-1beta on induction of AQP4 were concentration and time dependent. The effects of IL-1beta on AQP4 were mediated through IL-1beta receptors because they were abolished by co-incubation with IL-1 receptor antagonist. It appeared that IL-1beta increased the level of AQP4 mRNA without involvement of de novo protein synthesis because cycloheximide, a protein synthesis inhibitor, did not inhibit the effects of IL-1beta. Inhibition of the nuclear factor-kappaB (NF-kappaB) pathway blocked the induction of AQP4 by IL-1beta in a concentration-dependent manner. These findings show that IL-1beta induces expression of AQP4 through a NF-kappaB pathway without involvement of de novo protein synthesis in rat astrocytes.     

Temporal Expression of mRNAs for Neuropoietic Cytokines, Interleukin-11 (IL-11), Oncostatin M (OSM), Cardiotrophin-1 (CT-1) and Their Receptors (IL-11Rα and OSMRβ) in Peripheral Nerve Injury

The mRNA expression pattern of the neuropoietic cytokines, interleukin-11 (IL-11), oncostatin M (OSM) and cardiotrophin-1 (CT-1), and their receptor components (IL-11R and OSMR) was examined in peripheral nerves on two different types of injury, crush and transection. The IL-11 mRNA increased after nerve damage and immediately returned to control levels. The OSM mRNA expression increased rapidly after nerve injury and relatively high expressions were maintained for at least 14 days. The CT-1 mRNA was not expressed in any time before and after the injury. Interestingly, IL-11R was expressed in the intact nerve and decreased after injury. The expression of OSMR increased slightly after the injury. Moreover, temporal mRNA expression pattern of these neuropoietic cytokines and receptors was similar between the crushed and transected models. Each neuropoietic cytokine of IL-11, OSM and CT-1 has its own specific temporal mRNA expression pattern, which is also different from those of ciliary neuro-trophic factor (CNTF), leukemia inhibitory factor (LIF) and interleukin-6 (IL-6). These results suggest that all neuropoietic cytokines have distinctive functions in nerve degeneration and repair process in response to peripheral nerve injury.     

Induction of the synthesis of the C-X-C chemokine interferon-γ-inducible protein-10 in experimental canine endotoxemia

Endotoxemia is associated with a systemic inflammatory response leading to organ-specific leukocyte recruitment and tissue injury. Chemokine expression has been demonstrated in various models of sepsis and may mediate tissue infiltration with inflammatory cells. In this study we examined expression of the C-X-C chemokine interferon-gamma-inducible protein-10 (IP-10), a potent T-lymphocyte chemoattractant, in a canine model of endotoxemia and investigated mechanisms of cytokine-mediated IP-10 induction in endothelial cells. Control canine tissues showed negligible expression of IP-10 message, with the exception of the spleen. Endotoxemic dogs demonstrated a robust induction of IP-10 mRNA in the heart, lung, kidney, liver, and spleen. Immunohistochemical studies indicated that IP-10 was predominantly localized in cardiac venular endothelial cells, bronchial epithelial cells, renal mesangial cells, and in the splenic red pulp of endotoxemic dogs. In addition, IP-10 expression was associated with T-lymphocyte infiltration in canine tissues. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) induced a marked upregulation of IP-10 message in canine venular endothelial cells. IP-10 expression in TNF-alpha-stimulated endothelial cells peaked at 6 h of stimulation and returned to baseline levels after 24 h. In addition, macrophage colony-stimulating factor (M-CSF) induced a dose-dependent induction of IP-10 mRNA in canine endothelial cells. M-CSF-mediated IP-10 expression peaked after 6 h of incubation and returned to baseline levels after 24 h. Canine endotoxemia is associated with a robust early expression of IP-10 in multiple tissues. IP-10 induction may be important in regulating lymphocyte recruitment and function. TNF-alpha, IL-1 beta, and M-CSF are potent inducers of IP-10 in canine endothelial cells and may indirectly mediate lymphocyte chemotaxis and activation in inflammatory processes.     

Interleukin-1beta up-regulates expression of neurofilament light in human neuronal cells

Elevated expression of interleukin-1 (IL-1beta), a pro-inflammatory cytokine secreted by activated microglia, is a pathogenic marker of numerous neurodegenerative processes including Alzheimer's disease (AD). We have characterized a link between IL-1beta and the 68-kDa neurofilament light (NF-L) protein, which is a major component of the neuronal cytoskeleton. Using human brain aggregate cultures, we found that IL-1beta treatment significantly increased NF-L expression in primary neurons. Analysis of mRNA levels demonstrated elevated NF-L expression within 72 h while imaging of neurons by immunofluorescent staining for NF-L confirmed IL-1beta-induced NF-L protein expression. These observations suggest a potential inflammatory-induced mechanism for deregulation of an important cytoskeletal protein, NF-L, possibly leading to neuronal dysfunction.     

肠缺血/再灌注损伤后白介素1-β水平与磷脂酶A2激活的关系

为了探讨肠缺血/再灌注损伤后IL-1β基因表达和蛋白含量变化与磷脂酶A2抑制之间的关系,采用大鼠肠缺血/再灌注损伤模型,在对照组,损伤组和磷脂酶A2抑制剂处理组动物中收集血清,肺灌洗液,腹腔灌洗液及全身重要脏器组织样品,采用放射免疫法测定IL-1β含量,并且RT-PCR法测定肺组织中IL-1β和Ⅱ型PLA2基因表达,结果表明,损伤后6h血清中IL-1β含量明显高于对照组;损伤后1和3h,腹腔注保IL-1β也明显高于对照组;损伤后肝组织中IL-1β水平有明显增加,而肺,肾、肠组织中IL-1β没有明显变化。损伤后肺灌洗液中IL-1β也明显高于对照组水平,肺组织中IL-1βmRNA表达增加,而Ⅱ型PLA2mRNA在损伤后表达反而有所下降,采用磷脂酶A2抑制剂氯喹,环氧化物酶抑制剂消炎痛,血小板活化因子受体阻断剂SR27417后,IL-1β蛋白和基因表达有不同的改变,提示肠缺血/再灌注损伤后一定时间内,肝内IL-1βmRNA表达和血中IL-1β水平明显增高,但是否与磷脂酶A2激活或其代谢产物的释放有关尚需进一步证明。     

Stat3-dependent induction of interleukin-3 receptor expression in leukemia inhibitory factor-stimulated M1 mouse leukemia cells

M1 mouse leukemia cells differentiate to macrophages/monocytes by the stimulation of interleukin-6 (IL-6)/leukemia inhibitory factor (LIF). To identify new LIF-induced genes, we have performed representational difference analysis using M1 cells and cloned mouse interleukin-3 (IL-3) receptor beta subunit gene. The mRNA expression of both IL-3 receptor (IL-3R) alpha and beta subunits is upregulated after 1 h stimulation of LIF and remains to be elevated along the differentiation of M1 cells. This induction is almost completely suppressed in M1 cells expressing a dominant negative form of Stat3. Furthermore, we show that IL-3-induced Stat5 phosphorylation increases in LIF-stimulated M1 cells. These results suggest that Stat3 may play a role in the differentiation of myeloid cells by regulating IL-3R expression.     

The influence of kainic acid on core temperature and cytokine levels in the brain

Excitotoxic brain injury is associated with hyperthermia, and there are data showing beneficial effects of hypothermia on neurodegeneration and that hyperthermia facilitates the neurodegeneration. Cytokines are inflammatory proteins that seem to be involved in the neuroinflammation associated with epilepsy. Core temperature changes caused by the epileptogenic glutamate analogue kainic acid (KA) were investigated in relation to changes in levels of the pro-inflammatory cytokines interleukin-1beta (IL-1beta) and interleukin-6 (IL-6), and the endogenous interleukin-1 receptor antagonist (IL-1ra). The temperature was measured every 10 min during the first hour, and at 90 and 120 min, and hourly until 8 h after KA-injection (10 mg/kg). The cytokines were measured in the hypothalamus, a site of temperature regulation, and in hippocampus, cerebellum, and frontal cortex. KA induced a brief hypothermia followed by hyperthermia. IL-1beta levels were increased after KA-administration in all brain regions examined and, excepting hippocampus, returned to baseline levels at 24 h. The hippocampal IL-1ra levels were significantly increased at 24 h, whereas no changes in IL-6 levels were observed. The changes in IL-1beta levels and in ratios between the levels of the three cytokines, may account for some of the temperature changes and the behavioural manifestations induced by KA.     

Regulation of plasminogen activitor inhibitor-1 in human adipose tissue: interaction between cytokines, cortisol and estrogen.

To investigate further the role of plasminogen activator inhibitor-1 (PAI-1) in human adipose tissue, the regulation of cytokines, cortisol (dexamethasone) as well as estrogen on PAI-1 were determined in human adipose tissue fragments. PAI-1 activity was increased in human adipose tissue fragments incubated for 48 h with interleukin-1beta (IL-1beta) (2.6-fold, p < 0.01) and tumor necrosis factor-alpha (2.3-fold, p < 0.01). Incubation with interleukin-6 revealed a non-significant decrease in PAI-1 activity. Parallel findings were obtained when studying the PAI-1 mRNA expression. Dexamethesone increased PAI-1 activity after incubation for 8 h (p < 0.05) and enhanced the stimulation of IL-1beta after 8 h incubation. However, after 24 and 48 h, dexamethasone significantly reduced the IL-1beta induced increase in PAI-1 activity by 24-52% (p < 0.05), accordingly, PAI-1 mRNA expression was reduced 60%. Finally, the induction of PAI-1 activity and PAI-1 mRNA expression by IL-1beta was attenuated by estrogen (17.8+/-4.9%, p < 0.05 and 20.9+/-5.8%, p < 0.05, respectively). These results indicate that multiple cytokines, estrogen and dexamethasone may be involved in the regulation of PAI-1 biosynthesis in human adipose tissue, and suggest that there are interactions between cytokines and these steroid hormones. The interplay between these hormones may be of importance for the levels of PAI-1 observed in obesity and associated states.     

Interleukin-1beta induces interleukin-6 production through the production of prostaglandin E(2) in human osteoblasts, MG-63 cells.

This study was conducted to investigate the mechanism of interleukin-1beta (IL-1beta)-induced IL-6 production in human osteoblasts (MG-63 cells). Stimulation with IL-1beta resulted in the production of IL-6 and prostaglandin E(2) (PGE(2)). IL-6 production gradually increased and peaked 96 h after stimulation. IL-6 mRNA was detected between 4 and 72 h after IL-1beta stimulation. The patterns of PGE(2) production and the expression of cyclooxygenase-2 (COX-2) mRNA were biphasic after stimulation. Actinomycin D, cycloheximide, indomethacin, and NS-398 (COX-2 inhibitor) suppressed the production of IL-6 and PGE(2). Anti-PGE(2) antibody markedly reduced the production of IL-6. In addition, stimulation with 17-phenyl-PGE(2), a PGE receptor-1 (EP-1 receptor) agonist, led to the expression of IL-6 mRNA after pretreatment with IL-1beta. These findings indicate that IL-1beta-induced IL-6 production in MG-63 cells involves the following sequence of steps: IL-1beta-induced COX-2 activation, PGE(2) production, and EP-1 receptor signaling prior to IL-6 production.     

Brain trauma induces X-box protein 1 processing indicative of activation of the endoplasmic reticulum unfolded protein response

Brain trauma was induced in mice using a closed head injury (CHI) model. At 1, 6 or 24 h after trauma, brains were dissected into the cortex, striatum and hippocampus. Changes in levels of processed X-box protein 1 (xbp1), glucose-regulated protein 78 (grp78), growth arrest and DNA damage-inducible gene 153 (gadd153) and heat-shock protein 70 (hsp70) mRNA, indicating impaired endoplasmic reticulum (ER) and cytoplasmic functioning, were evaluated by quantitative PCR. In the cortex, processed xbp1 mRNA levels rose to 2000% of control 1 h after CHI, and stayed high throughout the experiments. In the hippocampus and striatum, processed xbp1 mRNA levels rose in a delayed fashion, peaking at 6 h (1000% of control) and 24 h after CHI (1500% of control) respectively. Levels of grp78 mRNA were only slightly increased in the cortex 24 h after CHI (150% of control), and were unchanged or transiently decreased in the hippocampus and striatum. Levels of gadd153 mRNA did not change significantly after trauma. A transient rise in hsp70 mRNA levels was observed only in the cortex, peaking at 1 h after CHI (600% of control). Processing of xbp1 mRNA is a sign of activation of the unfolded protein response indicative of ER dysfunction. The results suggest that brain trauma induces ER dysfunction, which spreads from the ipsilateral cortex to the hippocampus and striatum. These observations may have clinical implications and should therefore be considered for future investigations on therapeutic intervention of brain injury caused by contusion-induced neurotrauma.