Interleukin-18 (IL-18) mRNA expression and localization of IL-18 mRNA-expressing cells in the mouse uterus

Interleukin-18 (IL-18) belongs to the interleukin-1 family and was identified as an interferon-gamma inducing factor. We investigated IL-18 mRNA-expressing cells in the mouse uterus. By RNase protection assay, IL-18 mRNA and alpha subunit of IL-18 receptor mRNA were detected in the uterus. In the uterus, IL-18 mRNA levels increased during sexual maturation. In situ hybridization analysis demonstrated IL-18 mRNA-expressing cells in the mouse uterus of different ages. At 21 days of age, IL-18 mRNA-expressing cells were detected in the luminal epithelial cells and stromal cells although the IL-18 mRNA signal was weak. At 42 days of age, IL-18 mRNA signal was mainly detected in the stromal cells located near the myometrium, and in some of the luminal and glandular epithelial cells. In the uterus of 63-day-old adult mice, a strong hybridization signal for IL-18 mRNA was detected at estrus, but was weak at diestrus. IL-18 mRNA was mainly detected in the glandular epithelial cells and stromal cells. The effect of estradiol-17beta (E(2)) on IL-18 mRNA-expressing cells in the uterus was examined in ovariectomized mice. In oil-treated mice IL-18 mRNA signal was localized in luminal epithelial cells and stromal cells, while in E(2)-treated mice IL-18 mRNA signal was localized in stromal cells alone. These results suggest that the mouse uterus has an IL-18 system, and IL-18 exerts a physiological role within the uterus in a paracrine manner, and that IL-18 gene expression is regulated by estrogen.     

Role of TGF-beta1 in the development of pancreatic fibrosis in Otsuka Long-Evans Tokushima Fatty rats

Recently established Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a model of naturally occurring obesity diabetes, exhibit progressive accumulation of connective tissue in the pancreas. The present study was designed to determine the pathogenic role of transforming growth factor-beta1 (TGF-beta1) in the development of pancreatic fibrosis in OLETF rats by investigating the serial changes in the expression of TGF-beta1 and extracellular matrix (ECM) in the pancreas. Progressive proliferation of connective tissue arose from the interstitial region surrounding islets at 20 wk of age and extended to the exocrine pancreas adjacent to the islets. TGF-beta1 mRNA levels in the pancreas increased at 20 wk of age and reached a peak value at 30 wk of age. Fibronectin (FN) and procollagen types I and III mRNAs peaked at 20 wk of age and remained at higher levels than those in the nondiabetic counterparts Long-Evans Tokushima Otsuka rats until 50 wk of age. Immunoreactivities for TGF-beta1 and FN were found in islets of OLETF rats at 20 wk of age and were seen in acinar and interstitial cells at 50 wk of age. Moreover, alpha-smooth muscle actin was located at interstitial region surrounding the islets. Proliferation of the connective tissue in the pancreas of OLETF rats closely correlated with expression of TGF-beta1 and ECM. Our results suggest that the development of pancreatic fibrosis in OLETF rats extends from endocrine to exocrine pancreas and that TGF-beta1 is involved in pancreatic fibrosis of OLETF rats.     

RU486 antagonizes the inhibitory effect of peroxisome proliferator-activated receptor alpha on interleukin-6 production in vascular endothelial cells

Peroxisome proliferator-acitivated receptor alpha (PPARalpha) is a member of nuclear receptor superfamily. Recent studies have shown that the activators for PPARalpha inhibit the expression of some inflammatory molecules in vascular endothelial cells (ECs) and vascular smooth muscle cells, indicating the anti-inflammatory roles of PPARalpha on vascular walls. In this investigation, we showed that RU486, already proved to be an active anti-glucocorticoid and anti-progesterone agent, blocked the inhibition of tumor necrosis factor (TNF)-alpha-stimulated interleukin-6 (IL-6) production by the PPARalpha activator fenofibrate in human umbilical vein ECs. Transient transfection of bovine aortic ECs with an IL-6 promoter construct demonstrated that RU486 blocked the inhibitory effect of fenofibrate on TNF-alpha-induced IL-6 promoter activity. By fluorescence microscopy, RU486 was found to prevent fenofibrate-induced nuclear translocation of PPARalpha. Thus, RU486 has an antagonizing effect on PPARalpha-mediated down-regulation of IL-6 in vascular ECs. This effect may be exerted by its interference with the nuclear translocation of PPARalpha.     

Identification and characterization of a new phospholipase C-like protein, PLC-L(2)

We have isolated a cDNA encoding a novel protein, PLC-L(2), with homology to the phospholipase C-like protein PLC-L and delta-type phospholipase C. PLC-L(2) contains a relatively well-conserved PH domain, PLC catalytic region, and X and Y domains. However, it did not have PLC activity. This inactivation was thought to be caused by the replacement of two amino acids that are essential for PLC activity, His356 and Tyr552, with Thr and Phe in the X and Y domain. PLC-L(2) has a wide distribution with strong expression in skeletal muscle and mapped to chromosome 3p24-25. The PH domain of PLC-L(2) bound strongly to PI(4,5)P(2) and Ins(1,4,5)P(3), and moderately to PI(4)P and PI(3,4,5)P(3). PLC-L(2) predominantly localized to perinuclear areas in both myoblast and myotube C2C12 cells. Ectopically expressed GFP-PLC-L(2) also mainly localized in perinuclear areas, including endoplasmic reticulum in COS 7 cells. Furthermore, the expression of GFP-PH showed the same intracellular distribution as the full-length PLC-L(2). All these results suggest that PLC-L(2) plays an important role in the regulation of Ins(1,4, 5)P(3) around the endoplasmic reticulum on which the Ins(1,4,5)P(3) receptor exists.     

Effect of a noncompetitive antagonist (MK-801) of NMDA receptors on convulsions and brain amino acid level in E1 mice

Anticonvulsant action of MK-801, a novel noncompetitive antagonist of N-methyl-d-aspartate (NMDA) receptor, was examined in genetically epileptic E1 mice. Systemic injection of MK-801 (0.1–1.0 mg/kg) potently suppressed generalized tonic-clonic convulsions of in a dose-dependent manner (ED₅₀, 0.17 mg/kg). This anticonvulsant effect of MK-801 appeared at a dose which did not induced any obvious behavioral changes. Following the administration of a fully anticonvulsant dose of MK-801 (1 mg/kg), amino acid analysis revealed a significantly elevated level of glycine in the hippocampus. Levels of other amino acids including glutamate, aspartate, taurine, glutamine, alanine, and -aminobutyrate were not changed either in the hippocampus or in the cerebral cortex. This study suggests that NMDA system may play an essential role in seizure-triggering mechanisms in E1 mouse.     

Natural occurrence of phycoerythrocyanin-like pigment in cyanobacterial blooming samples dominated by Microcystis in Lake Kasumigaura

We describe the occurrence of phycocyanin and phycoerythrocyanin-likepigment in natural Microcystis colonies collected in Lake Kasumigaura.For differentiating pigments, the combination of simultaneousdetermination of molecular weights of and ß and subunitsby electrospray ionization mass spectrometry with HPLC separationand fluorescence measurements was used. It was suggested thatthe natural Microcystis colonies may contain the phycoerythrocyanin-likepigment, judged from the excitation and emission spectra. Measuredpigments consisted of different molecular weights of and ßsubunits, but the molecular weights of and ß subunitsin both phycocyanin and phycoerythrocyanin-like pigments werenot always identical.