Interleukin-6 Messenger Ribonucleic Acid Research Articles

Stimulation of prostanoids and IL-8 production in human gingival fibroblasts by Porphyromonas gingivalis LPS is associated with MEK/ERK signaling

Background/purposeVarious toxic products are generated by periodontal pathogens. Porphyromonas gingivalis has been found to generate lipopolysaccharide (LPS) that may potentially affect periodontal health. However, the precise effects of P. gingivalis LPS on human gingival fibroblasts (GFs) await further investigation. Materials and methodsHuman GFs were cultured and exposed to different concentrations of P. gingivalis LPS (0.1–10 μg/mL) for 24 hours. Cytotoxicity was analyzed by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. Total ribonucleic acid (RNA) was isolated and subjected to reverse transcriptase-polymerase chain reaction (RT-PCR) using specific primer sets. Culture medium was collected for determination of prostaglandin E2 (PGE2), PGF2α, and interleukin-8 (IL-8) production by enzyme-linked immunosorbent assay. ERK1/2 phosphorylation in GFs was evaluated by Western blotting. In some experiments, U0126 (a MEK/ERK inhibitor) was added to the GFs culture 30 minutes before LPS and culture medium was also collected for analysis. ResultsP. gingivalis LPS (0.1–10 μg/mL) showed little cytotoxicity and morphologic changes of GFs. P. gingivalis LPS obviously stimulated the cyclooxygenase-2 (COX-2) and IL-8 messenger RNA expression of GFs after 24 hours of exposure. Moreover, P. gingivalis LPS induced PGE2, PGF2α, and IL-8 production in GFs. P. gingivalis LPS also induced ERK1/2 phosphorylation in GFs. Stimulation of PGE2 production by P. gingivalis LPS was completely attenuated by U0126, whereas U0126 only partially inhibited the LPS-induced IL-8 production in the same condition. ConclusionOur data indicate that P. gingivalis LPS stimulates gene expression of differential inflammatory mediators (COX-2 and IL-8) as well as prostanoids and IL-8 production in GFs. These events are associated with MEK/ERK signaling and crucial in the pathogenesis of inflammatory periodontal diseases.

Differential interleukin-6 messenger ribonucleic acid expression and its distribution pattern in eutopic and ectopic endometrium

To evaluate the concentration and distribution pattern of interleukin-6-producing cells in ectopic and eutopic endometrium. Collection of both tissues at the proliferative cycle phase. A university endocrinology and laparoscopy program. Twelve samples from six women were obtained at operative laparoscopy in the proliferative phase of each woman's cycle. Paired sampling of ectopic (n = 6) and eutopic endometrium (n = 6). Concentration of IL-6 messenger RNA (mRNA) was measured by real-time RT-PCR, and its distribution was determined by in situ RT-PCR. In vitro RT-PCR analysis showed distinct bands at 234 bp and 115 bp for IL-6 mRNA in eutopic and ectopic endometrium and in placenta as positive control. Real-time RT-PCR indicated significantly higher expression of IL-6 in tissue with endometriosis than in tissue without. In all 12 samples subjected to in situ RT-PCR, positive signals of IL-6 mRNA were observed in cytoplasm of epithelial and stroma cells of ectopic and eutopic endometrium tissue. The significant IL-6 mRNA increase in endometriosis compared with in eutopic endometrium may play a role in the development of endometriosis and may provide new directions for endometriosis research.

The Mitogen-Activated Protein Kinase Dependent Expression of Prostaglandin H Synthase-2 and Interleukin-8 Messenger Ribonucleic Acid by Myometrial Cells: The Differential Effect of Stretch and Interleukin-1β

Infection and uterine stretch are the common causes of preterm labor. IL-1beta plays a key role in infection-induced preterm labor and increases prostaglandin H synthase 2 (PGHS-2) and IL-8 expression. We have shown that mechanical stretch of uterine myocytes in vitro up-regulates the expression of PGHS-2 and IL-8. In this study, we tested the hypotheses that both IL-1beta and mechanical stretch increase the myometrial expression of PGHS-2 and IL-8 via MAPK activation and that their effects are synergistic. MAPK activation was assessed in myocytes obtained from pregnant women undergoing cesarean section before the onset of labor after exposure to IL-1beta and stretch either alone or in combination. Specific inhibitors of ERK, p38, and c-Jun N-terminal kinase were used to define the role of each in the increased expression of PGHS-2 and IL-8 mRNA. We found that both IL-1beta and stretch activated all three MAPK subtypes but that they had no synergistic effect. The inhibitor studies showed that stretch-induced increases in both PGHS-2 and IL-8 mRNA expression were ERK1/2 and p38 dependent and that IL-1beta-induced increases of PGHS-2 mRNA expression were also ERK1/2 and p38 dependent, but those of IL-8 were dependent only on ERK1/2 activation. These data show that exposure of human uterine myocytes to both stretch and IL-1beta activates the MAPK system, which is responsible for the increase in PGHS-2 and IL-8 mRNA expression. We found no evidence of a synergistic effect of IL-1beta and stretch on myometrial expression of PGHS-2 and IL-8 mRNA.

Mechanical stretch of human uterine smooth muscle cells increases IL-8 mRNA expression and peptide synthesis.

Labour is associated with increased synthesis of interleukin-8 (IL-8) by the fetal membranes and myometrium, which leads to an inflammatory infiltrate. Stretch has been shown to increase the expression of contraction-associated proteins in animal models of labour and in human myocytes in vitro. In this study, we tested the hypothesis that mechanical stretch of human myometrial cells increases IL-8 messenger ribonucleic acid (mRNA) expression. We isolated myocytes from non-pregnant women undergoing hysterectomy and pregnant women undergoing Caesarean section before and after the onset of labour. Myocytes in culture were subjected to stretch of varying intensity (6-16%) and duration (1 or 6 h) using the Flexercell system. IL-8 mRNA expression was lowest in myocytes from pregnant women not in labour, intermediate in those from non-pregnant women and greatest in those from pregnant women in labour. Stretch increased IL-8 mRNA expression independent of reproductive state. The stretch-induced increase in IL-8 mRNA expression was associated with higher IL-8 levels in the culture supernatant and enhanced promoter activity. These data suggest that stretch contributes to the increase in myometrial IL-8 synthesis associated with the onset of labour in humans.

Enhanced expression of interleukin-8 and activation of nuclear factor kappa-B in endoscopy-negative gastroesophageal reflux disease.

Interleukin-8 (IL-8) mediates neutrophil trafficking via its receptors. Recent studies have shown that IL-8 is likely involved in the development and progression of erosive reflux esophagitis (RE), yet little is known about its implication in endoscopy-negative gastroesophageal reflux disease (GERD). The purpose of this study was to determine IL-8 messenger ribonucleic acid (mRNA) expression levels in endoscopy-negative GERD, along with assessment of nuclear factor kappaB (NF-kappaB) activation, which upregulates IL-8 expression. We studied 31 patients with endoscopy-negative GERD, 15 patients with erosive RE, and 15 asymptomatic controls. Paired biopsy samples were taken from the esophagus 3 cm above the gastroesophageal junction; one biopsy was snap-frozen for measurement of IL-8 mRNA levels by real-time quantitative polymerase chain reaction, and another was formalin-fixed for histopathological evaluation. In nine endoscopy-negative GERD patients, the IL-8 mRNA expression levels were measured before and 8 wk after treatment with lansoprazole. We also sampled additional specimens for NF-kappaB-DNA binding assay and immunohistochemical analyses of NF-kappaB p65 and p50 subunits, IL-8 and specific IL-8 receptor, CXCR-1. The relative IL-8 mRNA expression levels were significantly higher in esophageal mucosa of patients with endoscopy-negative GERD than those of the controls. The presence of basal zone hyperplasia and intraepithelial neutrophils, histopathological hallmarks of GERD, were associated with higher levels of IL-8 mRNA. Lansoprazole treatment significantly reduced the IL-8 mRNA expression levels. The esophageal epithelium of patients with GERD showed intense immunoreactivity for IL-8, and expressed CXCR-1 antigen. We found NF-kappaB activation in esophageal mucosa in GERD patients and the NF-kappaB subunits were localized predominantly in the nuclei of IL-8-expressing cells. Our results demonstrate enhanced mucosal expression of IL-8 in incipient GERD even without mucosal breaks. NF-kappaB activation may be implicated in the pathogenesis in GERD.

Messenger ribonucleic acid levels of interleukin-1β, interleukin-6 and interleukin-8 in the lower uterine segment increased significantly at final cervical dilatation during term parturition, while those of tumor necrosis factor α remained unchanged

Objective: To investigate the content of tumor necrosis factor α, interleukin-1β, interleukin-6 and interleukin-8 messenger ribonucleic acid (mRNA) in the lower uterine segment during term parturition. Study design: mRNA extracts from the lower uterine segment obtained from 53 women undergoing non-elective caesarean section at term were analyzed by semi-quantitative reverse transcriptase polymerase chain reaction. The patients were grouped according to cervical dilatation (less than 2 cm, n=18; 2 to less than 4 cm, n=13; 4–6 cm, n=7; more than 6 cm, n=15) at the time of caesarean section. Results: Interleukin-1β and interleukin-8 mRNA-contents at more than 6 cm cervical dilation were significantly higher than at less than 2 cm. The levels of interleukin-6 were already significantly increased in the 4–6 cm group, while the tumor necrosis factor α ribonucleic acid content did not change during parturition. Conclusion: The process of cervical dilatation during parturition at term is associated with an increased expression of interleukin-1β, interleukin-6 and interleukin-8 mRNA in the lower uterine segment. These findings support the theory that the activation of the inflammatory network plays an important role in the progress of cervical dilatation.

Interleukin-6 differentially stimulates haptoglobin production by peritoneal and endometriotic cells in vitro: a model for endometrial-peritoneal interaction in endometriosis.

Based on our previous observation that peritoneal endometriotic (PE) lesions synthesize in vivo substantially more haptoglobin (Hp) than related eutopic tissues, we hypothesized that this increase in Hp production was due to endometrial-peritoneal interactions. As interleukin-6 (IL-6) stimulates Hp in other tissues and is produced by endometrial cells, we tested our hypothesis by evaluating the effects of IL-6 on Hp production by PE cells, normal peritoneal (P) cells, and eutopic endometrial cells from women with (UE-E) and without endometriosis (UE-C) using semiquantitative RT-PCR and enzyme-linked immunoabsorbent assay. Endogenous production of IL-6 was also assessed. Treatment with human recombinant IL-6 and dexamethasone significantly increased Hp production by P or PE cells in a dose- and time-dependent manner (P < 0.05). Hp messenger ribonucleic acid was not detected in UE-E and UE-C cells in the absence or presence of IL-6 and dexamethasone. PE and UE-E cells expressed significantly more IL-6 messenger ribonucleic acid than P and UE-C cells (P < 0.05). Moreover, UE-E cells secreted 6 times more IL-6 protein than UE-C cells (P < 0.05). These findings support our hypothesis and suggest a novel endometrial-peritoneal interaction whereby locally synthesized IL-6 and Hp may participate in the establishment and persistence of peritoneal endometriosis.

Interleukin-8 messenger ribonucleic acid expression correlates with tumor progression, tumor angiogenesis, patient survival, and timing of relapse in non-small-cell lung cancer.

Tumor-associated angiogenesis is important for tumor growth and metastasis. Interleukin (IL)-8 was recently reported to be an important angiogenic factor both in vitro and in vivo. In this study we evaluated, for the first time, IL-8 messenger RNA (mRNA) expression in non-small-cell lung cancer (NSCLC), using real-time quantitative reverse-transcription-polymerase chain reaction, and correlated IL-8 mRNA expression in tumor and nontumor lung samples from 58 patients with NSCLC (29 with squamous cell carcinoma and 29 with adenocarcinoma, of whom 20 had Stage I, 10 had Stage II, and 28 had Stage III disease) with these patients' clinicopathologic characteristics, angiogenesis, and outcome. IL-8 protein expression and tumor microvessel count (MC) were assessed immunohistochemically. IL-8 mRNA expression was significantly greater in tumor tissue; high expression was highly associated with tumor in advanced stages (p = 0.03), distant lymph node metastasis (p = 0.02), high tumor MC (> 123) (p = 0.00003), short survival (< 26 mo) (p < 0.00001), and early relapse (< 16 mo) (p < 0.00001). Tumor MC correlated strongly with IL-8 mRNA expression (r = 0.56, p < 0.001). Multivariate analysis showed IL-8 mRNA expression and intratumor MC to be the most important predictors of patient survival and relapse. Thus, in NSCLC, IL-8 mRNA expression is strongly associated with tumor progression, tumor angiogenesis, survival, and time to relapse, suggesting its use as a prognostic indicator.

Perivascular Interleukin-8 Messenger Ribonucleic Acid Expression in Human Endometrium Varies across the Menstrual Cycle and in Early Pregnancy Decidua

Perivascular Interleukin-8 Messenger Ribonucleic Acid Expression in Human Endometrium Varies across the Menstrual Cycle and in Early Pregnancy Decidua

Perivascular interleukin-8 messenger ribonucleic acid expression in human endometrium varies across the menstrual cycle and in early pregnancy decidua.

Human endometrium and decidua contain large numbers of different leukocyte populations, the concentration of which fluctuates during the menstrual cycle and pregnancy. There is, for example, a large influx of neutrophils into premenstrual endometrium associated with an increased expression of interleukin (IL)-8 protein, which is chemotactic for neutrophils. Our aim in this study was to localize IL-8 messenger RNA (mRNA) expression in endometrium and decidua using in situ hybridization. In situ hybridization was carried out with a 35S-uridine 5'-triphosphate-labeled riboprobe using standard procedures. Late secretory endometrial and decidual biopsies demonstrated clear perivascular localization of IL-8 mRNA, with additional expression colocalized to activated macrophages. Midluteal endometrium showed minimal IL-8 expression, whereas endometrium obtained from women administered progesterone for 4 days from (LH peak + 8 days), to simulate luteal regression, demonstrated significantly increased localization of IL-8 mRNA, 48 h after withdrawal of progesterone. In conclusion, IL-8 mRNA expression is localized to perivascular cells of late secretory endometrium and decidua.

Experimental axonal injury triggers interleukin-6 mRNA, protein synthesis and release into cerebrospinal fluid.

Diffuse axonal injury is a frequent pathologic sequel of head trauma, which, despite its devastating consequences for the patients, remains to be fully elucidated. Here we studied the release of interleukin-6 (IL-6) into CSF and serum, as well as the expression of IL-6 messenger ribonucleic acid (mRNA) and protein in a weight drop model of axonal injury in the rat. The IL-6 activity was elevated in CSF within 1 hour and peaked between 2 and 4 hours, reaching maximal values of 82,108 pg/mL, and returned to control values after 24 hours. In serum, the levels of IL-6 remained below increased CSF levels and did not exceed 393 pg/mL. In situ hybridization demonstrated augmented IL-6 mRNA expression in several regions including cortical pyramidal cells, neurons in thalamic nuclei, and macrophages in the basal subarachnoid spaces. A weak constitutive expression of IL-6 protein was shown by immunohistochemical study in control brain. After injury, IL-6 increased at 1 hour and remained elevated through the first 24 hours, returning to normal afterward. Most cells producing IL-6 were cortical, thalamic, and hippocampal neurons as confirmed by staining for the neuronal marker NeuN. These results extend our previous studies showing IL-6 production in the cerebrospinal fluid of patients with severe head trauma and demonstrate that neurons are the main source of IL-6 after experimental axonal injury.

The effect of transforming growth factor and interleukin-10 on interleukin-8 release by human amniochorion may regulate histologic chorioamnionitis

OBJECTIVE: Amniochorion is a source of interleukin-8 during infection and inflammation. In this study we investigate the role of 2 immunoinhibitory cytokines, transforming growth factor and interleukin-10, in regulating interleukin-8 production from human fetal membranes and define their mechanism of regulation. STUDY DESIGN: Amniochorion was placed in an organ explant system for 72 hours. Tissues were stimulated with lipopolysaccharide (50 ng/mL), lipopolysaccharide plus transforming growth factor-β (50/50, 50/100), transforming growth factor-β (50 and 100 ng/mL), lipopolysaccharide plus interleukin-10 (50/50 and 50/100), and interleukin-10 (50 and 100 ng/mL) in culture. Tissue and media samples were frozen until quantitation of interleukin-8 messenger ribonucleic acid and protein. Quantitation of messenger ribonucleic acid was performed by quantitative competitive polymerase chain reaction and protein by enzyme-linked immunoassay, respectively. RESULTS: Lipopolysaccharide-stimulated tissues produced approximately 6 × 10 6 molecules per microliter of interleukin-8 messenger ribonucleic acid compared with 6 × 10 3 molecules per microliter in controls. Transforming growth factor-β alone and lipopolysaccharide plus transforming growth factor-β stimulation produced 6 × 10 5 and 6 × 10 4 molecules of interleukin-8 messenger ribonucleic acid per microliter, respectively. Tissues stimulated with lipopolysaccharide plus 50 ng/mL interleukin-10 produced approximately 600 molecules per microliter of interleukin-8 messenger ribonucleic acid, whereas no amplifiable messenger ribonucleic acid was detected in tissues treated with lipopolysaccharide plus 100 ng/mL interleukin-10. Tissues treated with interleukin-10 alone produced 6 × 10 3 molecules of messenger ribonucleic acid, similar to control levels. Enzyme-linked immunosorbent assay data showed similar levels of interleukin-8 peptide release from lipopolysaccharide and lipopolysaccharide plus transforming growth factor-β–treated fetal membranes. A dose-dependent decrease in interleukin-8 peptide release was seen in tissues treated with lipopolysaccharide plus interleukin-10, whereas stimulation with transforming growth factor or interleukin-10 alone resulted in interleukin-8 peptide release similar to that of control levels. CONCLUSION: Transforming growth factor-β seems to have no effect on interleukin-8 protein production in the presence of an infectious agent; however, a drop in messenger ribonucleic acid levels was observed. Interleukin-10 in the presence of lipopolysaccharide showed down-regulation of interleukin-8 messenger ribonucleic acid expression and peptide production. These data suggest that fetal membrane interleukin-8 production can be controlled by interleukin-10 during an infectious process. (Am J Obstet Gynecol 1998;179:794-9.)

Interleukin-8 in the human endometrium.

We have previously shown that interleukin-8 (IL-8), a cytokine with neutrophil chemotactic/activating and T cell chemotactic activity, is produced by human endometrial stromal and glandular cells in culture. The present study investigated the temporal and spatial expression of IL-8 messenger ribonucleic acid (mRNA) and protein in the human endometrium. Endometrial tissue (n = 52) was obtained from human uteri after hysterectomy conducted for reasons other than endometrial disease or from endometrial biopsies. The day of the menstrual cycle was established from women's menstrual history and was confirmed by histology. Half of the tissues (n = 26) were snap-frozen in liquid nitrogen, cellular RNA was extracted, and Northern blots were hybridized with a riboprobe complementary to a specific sequence of IL-8 mRNA. The remaining tissues (n = 26) were processed for frozen sections, and immunohistochemistry was performed using mouse antihuman IL-8 antibody. Comparison of IL-8 mRNA levels throughout the menstrual cycle revealed that late secretory and early to midproliferative phase IL-8 expression was significantly greater than midcycle expression (P < 0.02). Analysis of the IL-8 immunohistochemistry revealed that IL-8 protein is found in the surface epithelium and glands throughout the menstrual cycle. There was no detectable immunoreactive IL-8 in the stromal cells. We conclude that IL-8 is produced in the human endometrium in vivo, and the variations of IL-8 mRNA throughout the menstrual cycle suggest that sex hormones may regulate its gene expression. We speculate that IL-8 may modulate the timely recruitment of neutrophils and lymphocytes into the endometrium.

Evidence for a neutrophil–interleukin-8 system in human folliculogenesis

OBJECTIVE: This study was conducted to determine whether polymorphonuclear leukocytes (neutrophils) and the potent chemoattractant interleukin-8 are associated with follicle development in the normal human ovary. STUDY DESIGN: We performed a morphometric analysis of neutrophils in 268 human ovarian follicles, of which 199 were preantral and 69 were antral. In each antral follicle the numbers of mitotic, apoptotic, and total granulosa cells were counted to determine healthy and atretic follicles. Interleukin-8 protein and messenger ribonucleic acid were detected by immunohistochemistry and in situ hybridization, respectively. RESULTS: Antral follicles contained relatively large numbers of neutrophils within the theca vasculature. The density of neutrophil was twofold greater ( p < 0.05) in atretic versus healthy follicles. The neutrophil index (neutrophils/granulosa cells × 1000) was inversely correlated to the number of granulosa cells per follicle. Immunoreactive interleukin-8 was detected in the theca and granulosa cells of most all antral follicles examined. Interleukin-8 messenger ribonucleic acid was demonstrated in theca and granulosa cells of some but not all follicles examined. CONCLUSIONS: Neutrophils are present in the theca of developing antral follicles, increase in number during atresia, and are associated with expression of interleukin-8 in the follicle wall. (Am J Obstet Gynecol 1998;178:650-7.)

Expression of pro-inflammatory cytokines by flow-sorted alveolar macrophages in severe pneumonia

The aim of the present study was to further characterize the role of alveolar macrophages (AM) in acute human lung inflammation by evaluating their capacity to produce pro-inflammatory cytokines such as tumour necrosis factor (TNF)-alpha, interleukin (IL)-6 and IL-8. Patients with severe community-acquired pneumonia (CAP; n=12) and healthy volunteers (n=10) underwent bronchoalveolar lavage (BAL). AM were separated to high purity (>96%) using fluorescence-activated cell sorting. We determined the TNF-alpha, IL-6 and IL-8 cytokine gene expression in AM ex vivo using semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR). Moreover, we measured in vitro unstimulated, lipopolysaccharide (LPS)- and LPS/interferon-gamma inducible TNF-alpha, IL-6 and IL-8 cytokine release and evaluated samples of BAL fluids for the same pro-inflammatory cytokines using an enzyme-linked immunosorbent assay (ELISA). We found increased TNF-alpha, IL-6 and IL-8 messenger ribonucleic acid (mRNA) levels in AM from CAP patients that were significantly elevated only for IL-8. When challenged with endotoxin in vitro, AM obtained from CAP patients showed a strongly reduced potential to release TNF-alpha and IL-6 compared to healthy controls, whereas IL-8 secretion did not differ significantly between groups. Moreover, stimulation of AM from CAP patients with LPS plus IFN-gamma augmented TNF-alpha and IL-6 cytokine release to near normal levels. Interestingly, no TNF-alpha protein was measured in BAL samples from CAP patients, whereas IL-6 and IL-8 protein levels were found to be significantly increased. Together, highly purified alveolar macrophages from community-acquired pneumonia patients show relatively low ex vivo tumour necrosis factor-alpha and interleukin-6 but not interleukin-8 messenger ribonucleic acid levels that are associated with a decreased pro-inflammatory cytokine release in vitro which, however, can be restored by concurrent interferon-gamma stimulation.

Interleukin-1 increases expression of the LYT-10 (NFκB2) proto-oncogene/transcription factor in renal cell carcinoma lines

The LYT-10 gene was initially cloned by virtue of its disruption by the translocation breakpoint in some †(10;14) lymphoid neoplasms. LYT-10 is now known to encode a component of the NF- κB family of transcriptional activators and has therefore also been designated NFκB2. Activation of NF-κB is generally associated with its transfer to the nucleus and is followed by a rapid increase in expression of its target genes, which include cytokines such as interleukin-6 (IL-6). IL-6 can also be induced by other transcription factors such as NF-IL6. We studied the interaction of IL-1 and these transcription factors in two renal cell carcinoma cell lines (ACHN and Caki-1). These lines produce high levels of IL-6, show endogenous chloramphenicol acelyltransferase activity for the IL-6 promoter, and have high basal levels of transcripts encoding the NF- κB components Lyt-10, p50, and p65 as well as the NF-IL6 trancription factor. IL-l α and IL-Iβ markedly increased steady-state levels of LYT-10 (NF κB2) transcripts and nuclear Lyt-10 protein in both cell lines. Levels of the NF κB1 (p50-encoding), p65, and NF-IL6 transcripts also increased after IL-1 exposure. These changes were accompanied by a 20-fold or greater increase in levels of IL-6 messenger ribonucleic acid (mRNA) and protein. Our observations suggest that the mechanism by which IL-1 α or IL-1β induces IL-6 may be mediated through increases in LYT-10 mRNA and protein levels as well as increases in expression of other transcription factors (NF κB1, p65, and NF-IL6), in addition to the known ability of IL-1 to post-translationally activate NF- κB.

Growth hormone increases interleukin-6 produced by human osteoblast-like cells.

Physiological levels of GH are necessary for normal bone remodeling. GH treatment increases bone resorption and results in enhanced bone formation. The aim of the present study was to investigate whether the GH-induced increase in bone resorption could be mediated by a regulation of interleukin-6 (IL-6) production by human osteoblast-like cells. Cultures of human osteoblast-like cells were established from trabecular bone. Ribonuclease protection analysis demonstrated a high expression of the IL-6 messenger ribonucleic acid (mRNA) transcript in osteoblast-like cells, bone, and muscle, whereas expression was lower in liver. GH increased IL-6 mRNA levels as well as IL-6 protein released into the culture medium from human osteoblast-like cells in a time- and dose-dependent manner, with a maximal effect at 100 micrograms/L (mRNA, 322 +/- 95% of control; protein, 576 +/- 155% of control). In conclusion, GH increases IL-6 produced by human osteoblast-like cells. This in vitro evidence suggests, for the first time, a mechanistic paradigm by which GH modulates bone resorption.

Interleukin-10 inhibition of interleukin-6 in human amniochorionic membrane: Transcriptional regulation

OBJECTIVE: Our purpose was to study the regulatory effects of recombinant interleukin-10 on interleukin-6 messenger ribonucleic acid and protein production by human fetal membranes. STUDY DESIGN: Amniochorionic membranes were collected from women undergoing elective cesarean section. Membranes were maintained in an organ explant system and stimulated with media containing lipopolysaccharide (50 ng/ml) and various amounts of recombinant interleukin-10 (10, 50, 100 ng/ml). Experiments were conducted in a dose- and time-dependent manner. Transcription and translation of interleukin-6 were monitored with quantitative reverse transcriptase - polymerase chain reaction and enzyme-linked immunosorbent assay. RESULTS: Interleukin-10 stimulation of amniochorionic membranes in culture produced a dose-dependent decrease in the production of interleukin-6 messenger ribonucleic acid and protein. Quantitative polymerase chain reaction was used to document a decrease in interleukin-6 messenger ribonucleic acid, which paralleled the decrease in peptide levels as detected with enzyme-linked immunosorbent assay. The interleukin-10 effect was present only when tissue was concurrently stimulated with lipopolysaccharide. Interleukin-10 inhibition could not be produced in the absence of lipopolysaccharide stimulation. CONCLUSION: Addition of interleukin-10 to culture media leads to transcriptional regulation of interleukin-6, which results in decreased production of both messenger ribonucleic acid and protein by human amniochorionic membranes. The decrease in interleukin-6 is a dose-dependent effect of interleukin-10. This finding may have important implications with respect to a possible role for interleukin-10 or an interleukin-10 stimulatory factor in the management of preterm labor associated with the presence of inflammatory cytokines. (Am J Obstet Gynecol 1996;175:1057-65.)

Modulation of the levels of interleukin-8 messenger ribonucleic acid and interleukin-8 protein synthesis in human endometrial stromal cells by transforming growth factor-beta 1

Modulation of the levels of interleukin-8 messenger ribonucleic acid and interleukin-8 protein synthesis in human endometrial stromal cells by transforming growth factor-beta 1

Modulation of the levels of interleukin-8 messenger ribonucleic acid and interleukin-8 protein synthesis in human endometrial stromal cells by transforming growth factor-beta 1.

Selected functions of uterine endometrium of ovulatory women before and during pregnancy appear to be modulated by cytokines and other paracrine-acting factors. Some of these functions are regulated, in turn, by cyclic changes in ovarian steroid secretion or by pregnancy-induced endocrine and paracrine factors. The recruitment of specific types and numbers of bone marrow-derived cells into the endometrium occurs in a predictable manner with hormonal changes of the ovarian cycle, during the process of endometrial decidualization, at the time of blastocyst implantation, and during pregnancy, parturition, and the puerperium. As part of an investigation of the regulation of the leukocyte population of endometrium/decidua, this study was conducted to evaluate further the regulation of interleukin-8 (IL-8) gene expression by transforming growth factor-beta (TGF beta). IL-8 is a neutrophil chemoattractant/activating and T cell chemotactic factor as well as a chemotactic factor for fibroblasts. IL-8 is produced by mesenchymal cells of many tissues, including human endometrial stromal cells in culture. The level of IL-8 messenger ribonucleic acid (mRNA) in endometrial stromal cells and the accumulation of immunoreactive IL-8 in medium are increased by TGF beta 1 treatment of these cells. This response to TGF beta 1 is attributable primarily to an increase in the stability of IL-8 mRNA through a process that is dependent on protein synthesis. Transcription of the IL-8 gene in endometrial stromal cells is not increased, but, rather, is slightly decreased, by treatment with TGF beta 1. The findings of this study indicate that TGF beta may act in endometrial stroma to modulate the stability of IL-8 mRNA.