Involvement of interleukin-1 in the development of ulcerative colitis induced by dextran sulfate sodium in mice

Dextran sulfate sodium (DSS)-induced colitis in mice has been recognized as a model for human ulcerative colitis. Using this model, the effects of anti-murine interleukin 1beta (IL-1beta) antibodies (anti-muIL-1beta) and recombinant murine IL-1 receptor type I (rmuIL-1R) on the development of colitis were examined to determine whether IL-1 plays a role in colitis. Furthermore, RT-PCR amplification was used to examine for the presence of mRNAs for IL-1alpha and IL-1beta in the large intestine. In mice with colitis induced by DSS, administration of anti-muIL-1beta (5 mg/kg, once/week, i.p.) significantly suppressed body weight loss and shortening of the large intestine. Administration of rmuIL-1R (0.2 mg/kg or 1.0 mg/kg, once/day, i.v.) significantly suppressed shortening of the large intestine. Expression of mRNAs for IL-1alpha and IL-1beta was observed in the large intestine of mice which received distilled water containing 3% DSS for 5 days. The expression tended to increase in mice which received DSS for 11 days. In contrast, mRNA expression was not observed in mice which received distilled water without DSS. These results clearly demonstrate that IL-1 is involved in the development of DSS-induced colitis in mice and suggest that downregulation of IL-1 might be useful for the treatment of patients with ulcerative colitis.     

The insulin-like growth factors (IGF) and IGF type I receptor during postnatal growth of the murine mammary gland: sites of messenger ribonucleic acid expression and potential functions

The goals of this study were to determine the cellular sites of insulin-like growth factor (IGF) and IGF type-I receptor (IGF-IR) expression and to begin to elucidate functional roles for the IGFs during postnatal development of the murine mammary gland. Using in situ hybridization analyses, we determined that IGF-I, IGF-II, and IGF-IR messenger RNAs were expressed in the highly proliferative terminal end buds during pubertal ductal growth. Consistent with these data, IGF-I (in combination with mammogenic hormones) promoted ductal growth in pubertal stage mammary glands cultured in vitro. During postpubertal and pregnancy stages, IGF-II and IGF-IR continued to be expressed in ductal epithelium. Expression of IGF-II in ductal and alveolar epithelium correlated with the pattern of rapidly proliferating cells, as determined by incorporation of 5-Bromo-2'-deoxyuridine, suggesting a potential autocrine or paracrine role for IGF-II as a mitogen for ductal epithelial cells. IGF-I expression was reinitiated in mammary epithelium in the differentiated alveoli at the end of pregnancy, suggesting an additional role for this factor in maintenance of the alveoli during lactation. Taken together, these data support an in vivo role for locally-produced IGFs in promoting ductal growth during puberty and suggest that IGF-I and IGF-II may have distinct functions during pregnancy-induced alveolar development.     

Ligands that activate protein kinase-C differ in their ability to regulate basic fibroblast growth factor and insulin-like growth factor-I messenger ribonucleic acid levels

In this study, rat dermal fibroblasts were used as a model system to examine the ability of ligands that are known to activate protein kinase-C to regulate the levels of the mRNAs encoding basic fibroblast growth factor (bFGF) and insulin-like growth factor-I (IGF-I), two growth factors that are thought to be important in processes such as tissue repair and regeneration and wound healing. Treatment of fibroblasts with the phorbol ester phorbol 12-myristate 13-acetate (PMA), thrombin, bradykinin, serotonin, angiotensin-II, or bombesin increased protein kinase-C activity to a similar degree. Treatment of fibroblasts with 1 microM serotonin transiently increased bFGF mRNA levels about 3-fold compared to the level in control cells maintained in serum-free medium with 0.25% BSA and decreased IGF-I mRNA levels by approximately 50% compared to the level in control cells. This is similar to the previously described changes induced by bradykinin in these cells, but different from the more marked and sustained changes induced by thrombin and PMA. In contrast, angiotensin-II and bombesin had no effect on bFGF or IGF-I mRNA levels. The effects of serotonin, bradykinin, and PMA on bFGF and IGF-I mRNA levels were abrogated by preincubation of cells in 250 nM PMA to down-regulate protein kinase-C. In contrast, the effect of thrombin on bFGF mRNA levels was only partially inhibited by down-regulation of protein kinase-C, while its effect on IGF-I mRNA levels was unaffected. The activation of signaling pathways by the different ligands was further investigated to begin to determine the mechanism for the differences in the effects of thrombin vs. serotonin and bradykinin and in the effects of these three ligands vs. angiotensin-II and bombesin. All of the ligands activated phospholipase-D to a similar degree, suggesting that activation of this enzyme was not responsible for the differential effects of the ligands. In contrast, thrombin, serotonin, and bradykinin had marked effects on the hydrolysis of phosphatidylcholine and phosphatidylinositol, whereas bombesin and angiotensin-II had a small effect on phosphatidylcholine hydrolysis and no effect on phosphatidylinositol hydrolysis.(ABSTRACT TRUNCATED AT 400 WORDS)     

Hepatic growth hormone receptor, insulin-like growth factor I, and insulin-like growth factor-binding protein messenger RNA expression in pediatric liver disease

BACKGROUND: Previous studies have shown "beat-to-beat" variation in systemic BP with high-frequency jet ventilation (HFJV). However, it is not clear if such changes are paralleled by changes in cardiac output. OBJECTIVE: To characterize the effect of HFJV near or equal to the heart rate (HR) on beat-to-beat cardiac output in an adult human subject with ARDS. DESIGN: Case study. SETTING: ICU, university teaching hospital. PATIENTS: One patient with end-stage liver disease complicated by sepsis, severe pancreatitis, ARDS, and multisystem organ failure. METHODS: The patient was intubated, sedated, paralyzed, and ventilated with controlled mechanical ventilation (CMV). Ventilatory mode was then switched to HFJV at fixed frequencies (f) near but not equal to the HR (f= 100, 110, and 120 beats/min; HR=108/min). HFJV was then synchronized to the ECG such that f and HR were equal. Continuous cardiac output (COc) was monitored during change of ventilator mode from CMV to fixed-rate HFJV to synchronized HFJV, then followed through progressive delays in jet triggering within the cardiac cycle during the synchronous HFJV mode. COc was monitored by arterial pulse-contour analysis, allowing assessment of beat-to-beat changes in cardiac output. MEASUREMENTS AND MAIN RESULTS: A cyclic variation in COc equal to the beat frequency difference between f and HR was observed (harmonic interaction) during fixed-rate HFJV. This COc oscillation was abolished during synchronous HFJV. COc was significantly greater during systolic synchronous HFJV as compared to diastolic synchronous HFJV or fixed-rate HFJV (10.1 to 9.0 [p<0.05] and to 8.6 [p<0.05] L/min, systolic synchronous to diastolic synchronous and to fixed-rate HFJV, respectively). CONCLUSIONS: This study demonstrates instantaneous variations in cardiac output in a human subject with fixed rates of HFJV near to the HR in humans. These variations are abolished by synchronous HFJV but cardiac output was dependent on the timing of the HFJV inspiration in relation to the cardiac cycle. COc is a potentially valuable method to monitor sudden changes in cardiac output and facilitate attempts to maximize cardiac output during synchronized HFJV.     

Concerted regulation of low density lipoprotein receptor gene expression by follicle-stimulating hormone and insulin-like growth factor I in porcine granulosa cells: promoter activation, messenger ribonucleic acid stability, and sterol feedback

The consequences of glucocorticoid receptor (GR) dysfunction for neuroimmunoendocrine responses to an inflammatory challenge were studied in transgenic mice expressing antisense RNA directed against the GR [GR-impaired (GR-i) mice]. Mice were implanted intraperitoneally with a biotelemetry transmitter to monitor body temperature and locomotion. GR-i mice showed decreased locomotion and body temperature during the dark phase of the diurnal cycle. Intraperitoneal administration of saline caused a rapid increase in body temperature in control mice, which was terminated within 90 min. In GR-i mice, however, body temperature remained elevated for about 6 h. Intraperitoneal injection of endotoxin (10 micrograms/mouse) produced a biphasic fever in control mice. However, in endotoxin-injected GR-i mice, body temperature was not significantly different from their saline-injected controls during the first 6 h. Body temperature then increased and remained elevated during the night period. Both strains showed hypolocomotion after endotoxin. In a second experiment, mice were injected intraperitoneally with saline or endotoxin and killed after 1, 3, 6 or 24 h. In GR-i mice, endotoxin caused an augmented rise in plasma ACTH, but not in corticosterone levels. The endotoxin-induced increase in serum levels of interleukin-1 beta and interleukin-6 was not different between the strains. However, whereas in control mice tumour necrosis factor-alpha levels were below detection at the time points studied, substantial levels of this cytokine were found in the serum of GR-i mice 1 h after endotoxin administration. It may be concluded that life-long impairment of GR evolves in aberrant physiological and humoral responses to an acute inflammatory challenge. These findings expand our understanding about the neuroendocrine and physiological disturbances associated with stress-related disorders.     

Expression of transforming growth factor-beta 1 messenger ribonucleic acid and the modulation of deoxyribonucleic acid synthesis by transforming growth factor-beta 1 in human endometrial cells

OBJECTIVE: The purpose of this study was (1) to evaluate the potential sites of transforming growth factor-beta 1 synthesis in human endometrium by analyzing separated endometrial glands and stromal cells for transforming growth factor-beta 1 messenger ribonucleic acid by Northern analysis of total ribonucleic acid and (2) to investigate the effects of transforming growth factor-beta 1 on deoxyribonucleic acid synthesis in endometrial epithelial and stromal cells in culture. STUDY DESIGN: Endometrial glands and stroma from proliferative and secretory endometrium were isolated after collagenase treatment of endometrial tissue minces and were analyzed for transforming growth factor-beta 1 messenger ribonucleic acid by Northern analysis. We studied the effects of estradiol-17 beta and transforming growth factor-beta 1 on deoxyribonucleic acid synthesis in endometrial epithelium and transforming growth factor-beta 1 on stromal cells in culture by evaluating tritiated thymidine incorporation into trichloroacetic acid-precipitable material. RESULTS: Transforming growth factor-beta 1 messenger ribonucleic acid was detected for Northern analysis in separated endometrial stromal cells in levels that were greatest during the secretory phase and in greater levels than in epithelial cells from that same tissue. Transforming growth factor-beta 1 messenger ribonucleic acid in glandular epithelium in culture was not increased to detectable levels by treatment with transforming growth factor-beta 1. Deoxyribonucleic acid synthesis in endometrial glandular epithelium was inhibited by transforming growth factor-beta 1, but transforming growth factor-beta 1 stimulated deoxyribonucleic acid synthesis in endometrial stromal cells in culture. After treatment for 5 days with estradiol-17 beta (10(-8) mol/L), deoxyribonucleic acid synthesis in endometrial glands in culture was decreased by 40%. Transforming growth factor-beta 1 (1 ng/ml) did not alter this effect of estradiol-17 beta on deoxyribonucleic acid synthesis. CONCLUSIONS: Transforming growth factor-beta 1 acts to decrease deoxyribonucleic acid synthesis in epithelial cells and to increase it in stromal cells isolated from human endometrium and maintained in monolayer culture. Transforming growth factor-beta 1, potentially of stromal cell origin, could participate in the regulation of endometrial cell proliferation and differentiation in vivo.     

Protective effect of the insulin-like growth factor I receptor on apoptosis induced by okadaic acid

Okadaic acid (OKA), a potent inhibitor of serine phosphatases at concentrations as low as 20-25 nM, induces apoptosis of R- mouse embryo fibroblasts, which are 3T3-like cells devoid of type 1 insulin-like growth factor receptors (IGF-IRs). From R- cells, we have generated (by stable transfection) cell lines with IGF-IR numbers ranging from 0 (R- cells) to >10(6) receptors per cell. The wild-type IGF-IR protects R- cells from OKA-induced apoptosis, its protective effect being exquisitely dependent on the number of receptors. A small increment in wild-type receptor number (from 15 x 10(3) to 22 x 10(3) receptors/cell) is sufficient to change R(-)-derived cells from sensitive to resistant to apoptosis. We have also studied the effect of various mutations of the IGF-IR on its ability to protect R(-)-derived cells from OKA-induced apoptosis. Our data indicate a correlation between protection from apoptosis and the ability of the receptor to respond to insulin-like growth factor I with mitogenesis.     

Regulation of human dermal papilla cell production of insulin-like growth factor binding protein-3 by retinoic acid, glucocorticoids, and insulin-like growth factor-1

Insulin-like growth factor-1 (IGF1) has been reported to stimulate hair elongation and to facilitate maintenance of the hair follicle in anagen phase. However, little is known about IGF1 signaling in the hair follicle. In this study we investigate the effects of IGF1, glucocorticoids, and retinoids on dermal papilla (DP) cell production of insulin-like growth factor binding proteins (IGFBPs). IGFBPs comprise a family of IGF binding proteins that are produced and released by most cell types. They bind to IGFs to either enhance or inhibit IGF activity. In the present report we identify IGFBP-3 as being produced and released by cultured human dermal papilla (DP) cells. IGFBP-3 levels are increased fivefold by retinoic acid, eightfold by dexamethasone, and tenfold by IGF1. DP cells are known to produce IGF1, and so the observed stimulation of DP cell IGFBP-3 production by IGF1 is consistent with the idea that DP cells possess the IGF transmembrane receptor kinase and are autoregulated by IGFs. The level of another IGFBP, tentatively identified as IGFBP-2, is, in contrast, not regulated by these agents. IGFBP-3 has been shown to inhibit the activity of IGFs in a variety of systems. Our results are consistent with a model in which retinoids and glucocorticoids inhibit IGF action on DP cells and surrounding matrix cells by stimulating increased DP cell production of IGFBP-3. The IGFBP-3, in turn, forms a complex with free IGF1 to reduce the concentration of IGF1 available to stimulate hair elongation and maintenance of anagen phase.