Resetting central and peripheral circadian oscillators in transgenic rats

In multicellular organisms, circadian oscillators are organized into multitissue systems which function as biological clocks that regulate the activities of the organism in relation to environmental cycles and provide an internal temporal framework. To investigate the organization of a mammalian circadian system, we constructed a transgenic rat line in which luciferase is rhythmically expressed under the control of the mouse Per1 promoter. Light emission from cultured suprachiasmatic nuclei (SCN) of these rats was invariably and robustly rhythmic and persisted for up to 32 days in vitro. Liver, lung, and skeletal muscle also expressed circadian rhythms, which damped after two to seven cycles in vitro. In response to advances and delays of the environmental light cycle, the circadian rhythm of light emission from the SCN shifted more rapidly than did the rhythm of locomotor behavior or the rhythms in peripheral tissues. We hypothesize that a self-sustained circadian pacemaker in the SCN entrains circadian oscillators in the periphery to maintain adaptive phase control, which is temporarily lost following large, abrupt shifts in the environmental light cycle.

An assay for transforming growth factor-beta using cells transfected with a plasminogen activator inhibitor-1 promoter-luciferase construct

Transforming growth factor-beta (TGF-beta) is a potent regulator of cellular differentiation, proliferation, migration, and protein expression. These properties have been exploited to create a variety of bioassays for detecting the mature growth factor. In this paper, we describe a highly sensitive and specific, nonradioactive quantitative bioassay for TGF-beta based on its ability to induce plasminogen activator inhibitor-1 (PAI-1) expression. Mink lung epithelial cells (MLEC) were stably transfected with an expression construct containing a truncated PAI-1 promoter fused to the firefly luciferase reporter gene. Addition of TGF-beta (0.2 to > 30 pM) to the transfectants resulted in a dose-dependent increase in luciferase activity in the cell lysates. Although responsive to TGF-beta, this promoter fragment was only minimally influenced by other known inducers of PAI-1 expression. When compared to the widely used MLEC assay, this assay demonstrated greater sensitivity and specificity, allowing quantification of TGF-beta in complex biological solutions.

Differential reactivity of a novel monoclonal antibody (DF3) with human malignant versus benign breast tumors

We have defined a human breast tumor associated antigen using a murine monoclonal antibody (MAb DF3) prepared against a membrane-enriched fraction of a human breast carcinoma. This antigen has a MW of 290 kD and is detectable on the cell surface of human breast carcinoma cells using a live cell radioimmunoassay and fluorescence flow cytometry. More important, immunoperoxidase staining with MAb DF3 clearly distinguishes malignant and benign breast lesions. A cytoplasmic staining pattern has been observed with 40 of 51 (78%) breast carcinomas, but only one of 13 fibroadenoma or fibrocystic disease specimens. In contrast, reactivity of benign breast lesions with MAb DF3 primarily occurs along apical borders on ductules. These results demonstrate that the DF3 antigen is present on apical borders of more differentiated secretory mammary epithelial cells and in the cytosol of less differentiated cells.

Melatonin stimulates brain glutathione peroxidase activity

Exogenously administered melatonin causes a 2-fold rise in glutathione peroxidase activity within 30 min in the brain of the rat. Furthermore, brain glutathione peroxidase activity is higher at night than during the day and is correlated with high night-time tissue melatonin levels. Glutathione peroxidase is thought to be the principal enzyme eliminating peroxides in the brain. This antioxidative enzyme reduces the formation of hydroxyl radicals formed via iron-catalyzed Fenton-type reactions from hydrogen peroxide by reducing this oxidant to water. Since the hydroxyl radical is the most noxious oxygen radical known, induction of brain glutathione peroxidase might be an important mechanism by which melatonin exerts its potent neuroprotective effects.

Haematopoietic cell-specific CDM family protein DOCK2 is essential for lymphocyte migration

Cell migration is a fundamental biological process involving membrane polarization and cytoskeletal dynamics, both of which are regulated by Rho family GTPases. Among these molecules, Rac is crucial for generating the actin-rich lamellipodial protrusion, a principal part of the driving force for movement. The CDM family proteins, Caenorhabditis elegans CED-5, human DOCK180 and Drosophila melanogaster Myoblast City (MBC), are implicated to mediate membrane extension by functioning upstream of Rac. Although genetic analysis has shown that CED-5 and Myoblast City are crucial for migration of particular types of cells, physiological relevance of the CDM family proteins in mammals remains unknown. Here we show that DOCK2, a haematopoietic cell-specific CDM family protein, is indispensable for lymphocyte chemotaxis. DOCK2-deficient mice (DOCK2-/-) exhibited migration defects of T and B lymphocytes, but not of monocytes, in response to chemokines, resulting in several abnormalities including T lymphocytopenia, atrophy of lymphoid follicles and loss of marginal-zone B cells. In DOCK2-/- lymphocytes, chemokine-induced Rac activation and actin polymerization were almost totally abolished. Thus, in lymphocyte migration DOCK2 functions as a central regulator that mediates cytoskeletal reorganization through Rac activation.

Touchdown of the Hayabusa Spacecraft at the Muses Sea on Itokawa

After global observations of asteroid 25143 Itokawa by the Hayabusa spacecraft, we selected the smooth terrain of the Muses Sea for two touchdowns carried out on 19 and 25 November 2005 UTC for the first asteroid sample collection with an impact sampling mechanism. Here, we report initial findings about geological features, surface condition, regolith grain size, compositional variation, and constraints on the physical properties of this site by using both scientific and housekeeping data during the descent sequence of the first touchdown. Close-up images revealed the first touchdown site as a regolith field densely filled with size-sorted, millimeter- to centimeter-sized grains.

Congenital osteoclast deficiency in osteopetrotic (op/op) mice is cured by injections of macrophage colony-stimulating factor

Osteopetrotic (op/op) mice have a severe deficiency of osteoclasts, monocytes, and peritoneal macrophages because of a defect in the production of functional macrophage colony-stimulating factor (M-CSF) resulting from a mutation within the M-CSF gene. In this study, we examined whether daily 5-microgram injections of purified recombinant human M-CSF (rhM-CSF) for 14 d would cure these deficiencies in the mutant mice. Monocytes in the peripheral blood of the op/op mice were significantly increased in number after subcutaneous injections of the factor two or three times a day. In contrast, osteopetrosis in the long bones of op/op mice was completely cured by only one injection of rhM-CSF per day. Bone trabeculae in the diaphyses were removed. Many osteoclasts were detected on the surface of bone trabeculae in the metaphyses. Although development of tooth germs of uninjected op/op mice was impaired, rhM-CSF injection restored the development of molar tooth germs and led to tooth eruption as a consequence of the recovery of bone-resorbing activity. These results demonstrate that M-CSF is one of the factors responsible for the differentiation of osteoclasts and monocyte/macrophages under physiological conditions.

Isolation and sequencing of a cDNA coding for the human DF3 breast carcinoma-associated antigen

The murine monoclonal antibody (mAb) DF3 reacts with a high molecular weight glycoprotein detectable in human breast carcinomas. DF3 antigen expression correlates with human breast tumor differentiation, and the detection of a cross-reactive species in human milk has suggested that this antigen might be useful as a marker of differentiated mammary epithelium. To further characterize DF3 antigen expression, we have isolated a cDNA clone from a lambda gt11 library by screening with mAb DF3. The results demonstrate that this 309-base-pair cDNA, designated pDF9.3, codes for the DF3 epitope. Southern blot analyses of EcoRI-digested DNAs from six human tumor cell lines with 32P-labeled pDF9.3 have revealed a restriction fragment length polymorphism. Variations in size of the alleles detected by pDF9.3 were also identified in Pst I, but not in HindIII, DNA digests. Furthermore, hybridization of 32P-labeled pDF9.3 with total cellular RNA from each of these cell lines demonstrated either one or two transcripts that varied from 4.1 to 7.1 kilobases in size. The presence of differently sized transcripts detected by pDF9.3 was also found to correspond with the polymorphic expression of DF3 glycoproteins. Nucleotide sequence analysis of pDF9.3 has revealed a highly conserved (G + C)-rich 60-base-pair tandem repeat. These findings suggest that the variation in size of alleles coding for the polymorphic DF3 glycoprotein may represent different numbers of repeats.

Both hypertrophic and dilated cardiomyopathies are caused by mutation of the same gene, delta-sarcoglycan, in hamster: an animal model of disrupted dystrophin-associated glycoprotein complex

Cardiomyopathy (CM) is a primary degenerative disease of myocardium and is traditionally categorized into hypertrophic and dilated CMs (HCM and DCM) according to its gross appearance. Cardiomyopathic hamster (CM hamster), a representative model of human hereditary CM, has HCM and DCM inbred sublines, both of which descend from the same ancestor. Herein we show that both HCM and DCM hamsters share a common defect in a gene for delta-sarcoglycan (delta-SG), the functional role of which is yet to be characterized. A breakpoint causing genomic deletion was found to be located at 6.1 kb 5' upstream of the second exon of delta-SG gene, and its 5' upstream region of more than 27.4 kb, including the authentic first exon of delta-SG gene, was deleted. This deletion included the major transcription initiation site, resulting in a deficiency of delta-SG transcripts with the consequent loss of delta-SG protein in all the CM hamsters, despite the fact that the protein coding region of delta-SG starting from the second exon was conserved in all the CM hamsters. We elucidated the molecular interaction of dystrophin-associated glycoproteins including delta-SG, by using an in vitro pull-down study and ligand overlay assay, which indicates the functional role of delta-SG in stabilizing sarcolemma. The present study not only identifies CM hamster as a valuable animal model for studying the function of delta-SG in vivo but also provides a genetic target for diagnosis and treatment of human CM.

Roles of two VEGF receptors, Flt-1 and KDR, in the signal transduction of VEGF effects in human vascular endothelial cells

Vascular endothelial growth factor (VEGF) is a principal regulator of vasculogenesis and angiogenesis. VEGF expresses its effects by binding to two VEGF receptors, Flt-1 and KDR. However, properties of Flt-1 and KDR in the signal transduction of VEGF-mediated effects in endothelial cells (ECs) were not entirely clarified. We investigated this issue by using two newly developed blocking monoclonal antibodies (mAbs) against Flt-1 and KDR. VEGF elicits DNA synthesis and cell migration of human umbilical vein endothelial cells (HUVECs). The pattern of inhibition of these effects by two mAbs indicates that DNA synthesis is preferentially mediated by KDR. In contrast, the regulation of cell migration by VEGF appears to be more complicated. Flt-1 regulates cell migration through modulating actin reorganization, which is essential for cell motility. A distinct signal is generated by KDR, which influences cell migration by regulating cell adhesion via the assembly of vinculin in focal adhesion plaque and tyrosine-phosphorylation of focal adhesion kinase (FAK) and paxillin.

Blood blisterlike aneurysms of the internal carotid artery

OBJECT

An aneurysm arising from the anterior wall of the internal carotid artery (ICA) is a poorly understood entity. A small hemispherical bulge from the anterior wall of the ICA, which is called a "blood blisterlike aneurysm" (BBA), may be confused with a tiny berry aneurysm although the clinical features are distinctly different. This paper summarizes the clinical course of patients with this lesion to clarify the nature of the BBA.

METHODS

Six patients with BBAs who presented with subarachnoid hemorrhage (SAH) are described. In all patients, the initial angiogram obtained soon after SAH showed only a small bulge from the anterior wall of the ICA. In three of the six patients this bulge had progressed to a saccular appearance within a few weeks. The wall of the lesion was so thin and fragile that the aneurysm ruptured at the base during clipping or within a few hours after clipping in two patients.

CONCLUSIONS

From the authors' experience, as well as a review of the literature, which includes an autopsy study of similar cases, it is inferred that these lesions are focal wall defects covered only with thin fibrous tissue and that they are therefore not true aneurysms. Direct clipping often causes laceration of the lesion, whereas complete wrapping or clipping after wrapping is effective, but may fail to prevent growth of the aneurysm. Endovascular occlusion of the cervical ICA with or without bypass surgery, which is less risky than direct surgery, is another option.

Ets-1 regulates angiogenesis by inducing the expression of urokinase-type plasminogen activator and matrix metalloproteinase-1 and the migration of vascular endothelial cells

The coordinate induction of protease activities and cell migration is a principal feature of endothelial cells (ECs) invading the interstitial space in the initial step of angiogenesis. However, the molecular mechanisms of these events are not fully characterized. Ets-1 is a member of the ets gene family of transcription factors, which binds to the Ets binding motif in the cis-acting elements and regulates the expression of certain genes. Four typical angiogenic growth factors, aFGF, bFGF, VEGF, and EGF, induced the expression of ets-1 mRNA in either human umbilical vein endothelial cells (HUVECs), ECV-304 cells (immortalized HUVECs), or human omental microvascular endothelial cells (HOMECs). The expression of ets-1 reached its maximum at 2 hr after factor addition and then decreased to the basal level by 12 hr. For characterization of the role of Ets-1 in angiogenesis, ets-1 antisense and sense oligodeoxynucleotides (ODNs) were constructed. The ets-1 antisense ODN but not sense ODN efficiently blocked the synthesis of Ets-1 protein by human ECs in response to angiogenic growth factors. Moreover, the ets-1 antisense ODN but not sense ODN almost completely abolished the binding of endothelial cell extract to DNA containing the Ets binding motif. The expression of urokinase-type plasminogen activator and matrix metalloproteinase-1 and the migration of ECs in response to growth factors were significantly inhibited by ets-1 antisense ODN but not by sense ODN. Tube formation by HOMECs in type 1 collagen gel stimulated with EGF was abrogated by ets-1 antisense ODN. Finally, the expression of Ets-1 protein in ECs during angiogenesis in vivo was confirmed by an immunohistochemical analysis using a murine angiogenesis model. These results indicate that the induction of ets-1 mRNA is a mutual phenomenon in ECs stimulated with angiogenic growth factors. Ets-1 appears to play an important role in angiogenesis, regulating the expression of proteases and the migration of ECs.

CD8(+) T cell-mediated skin disease in mice lacking IRF-2, the transcriptional attenuator of interferon-alpha/beta signaling

The balanced action of cytokines is known to be critical for the maintenance of homeostatic immune responses. Here, we report the development of an inflammatory skin disease involving CD8(+) T cells, in mice lacking the transcription factor, interferon regulatory factor-2 (IRF-2). CD8(+) T cells exhibit in vitro hyper-responsiveness to antigen stimulation, accompanied with a notable upregulation of the expression of genes induced by interferon-alpha/beta (IFN-alpha/beta). Furthermore, both disease development and CD8(+) T cell abnormality are suppressed by the introduction of nullizygosity to the genes that positively regulate the IFN-alpha/beta signaling pathway. IRF-2 may represent a unique negative regulator, attenuating IFN-alpha/beta-induced gene transcription, which is necessary for balancing the beneficial and harmful effects of IFN-alpha/beta signaling in the immune system.

Inhibition of hypoxia-inducible factor 1 activity by nitric oxide donors in hypoxia

Nitric oxide (NO) is known to have various biologic and pathophysiologic effects on organisms. The molecular mechanisms by which NO exerts harmful effects are unknown, although various O2 radicals and ions that result from reactivity of NO are presumed to be involved. Here we report that adaptive cellular response controlled by the transcription factor hypoxia-inducible factor 1 (HIF-1) in hypoxia is suppressed by NO. Induction of erythropoietin and glycolytic aldolase A mRNAs in hypoxically cultured Hep3B cells, a human hepatoma cell line, was completely and partially inhibited, respectively, by the addition of sodium nitroprusside (SNP), which spontaneously releases NO. A reporter plasmid carrying four hypoxia-response element sequences connected to the luciferase structural gene was constructed and transfected into Hep3B cells. Inducibly expressed luciferase activity in hypoxia was inhibited by the addition of SNP and two other structurally different NO donors, S-nitroso-L-glutathione and 3-morpholinosydnonimine, giving IC50 values of 7.8, 211, and 490 microM, respectively. Inhibition by SNP was also observed in Neuro 2A and HeLa cells, indicating that the inhibition was not cell-type-specific. The vascular endothelial growth factor promoter activity that is controlled by HIF-1 was also inhibited by SNP (IC50 = 6.6 microM). Induction generated by the addition of cobalt ion (this treatment mimics hypoxia) was also inhibited by SNP (IC50 = 2.5 microM). Increased luciferase activity expressed by cotransfection of effector plasmids for HIF-1alpha or HIF-1alpha-like factor in hypoxia was also inhibited by the NO donor. We also showed that the inhibition was performed by blocking an activation step of HIF-1alpha to a DNA-binding form.

Prognostic factors for mature natural killer (NK) cell neoplasms: aggressive NK cell leukemia and extranodal NK cell lymphoma, nasal type

BACKGROUND

Patients with natural killer (NK) cell neoplasms, aggressive NK cell leukemia (ANKL) and extranodal NK cell lymphoma, nasal type (ENKL), have poor outcome. Both diseases show a spectrum and the boundary of them remains unclear. The purpose of this study is to draw a prognostic model of total NK cell neoplasms.

PATIENTS AND METHODS

We retrospectively analyzed 172 patients (22 with ANKL and 150 with ENKL). The ENKLs consisted of 123 nasal and 27 extranasal (16 cutaneous, 9 hepatosplenic, 1 intestinal and 1 nodal) lymphomas.

RESULTS

Complete remission rate for ENKL was 73% in stage I, but 15% in stage IV, which was consistent with that for ANKL (18%). The prognosis of ENKL was better than that of ANKL (median survival 10 versus 1.9 months, P < 0.0001) but was comparable when restricted to stage IV cases (4.0 months, P = 0.16). Multivariate analysis showed that four factors (non-nasal type, stage, performance status and numbers of extranodal involvement) were significant prognostic factors. Using these four variables, an NK prognostic index was successfully constructed. Four-year overall survival of patients with zero, one, two and three or four adverse factors were 55%, 33%, 15% and 6%, respectively.

CONCLUSION

The current prognostic model successfully stratified patients with NK cell neoplasms with different outcomes.

Role of the latent TGF-beta binding protein in the activation of latent TGF-beta by co-cultures of endothelial and smooth muscle cells

Transforming growth factor beta (TGF-beta) is released from cells in a latent form consisting of the mature growth factor associated with an aminoterminal propeptide and latent TGF-beta binding protein (LTBP). The endogenous activation of latent TGF-beta has been described in co-cultures of endothelial and smooth muscle cells. However, the mechanism of this activation remains unknown. Antibodies to native platelet LTBP and to a peptide fragment of LTBP inhibit in a dose-dependent manner the activation of latent TGF-beta normally observed when endothelial cells are cocultured with smooth muscle cells. Inhibition of latent TGF-beta activation was also observed when cells were co-cultured in the presence of an excess of free LTBP. These data represent the first demonstration of a function for the LTBP in the extracellular regulation of TGF-beta activity and indicate that LTBP participates in the activation of latent TGF-beta, perhaps by concentrating the latent growth factor on the cell surface where activation occurs.

Urotensin II is the endogenous ligand of a G-protein-coupled orphan receptor, SENR (GPR14)

Two molecular species of urotensin II (UII) were isolated from porcine spinal cords and identified as the endogenous ligands of a G-protein-coupled orphan receptor, SENR (sensory epithelium neuropeptide-like receptor), which is identical to GPR14. We established a CHO cell line stably expressing the rat SENR and investigated several tissue extracts to evoke the response mediated by the SENR. Extract from porcine spinal cords showed an activity of arachidonic acid metabolites release from SENR-expressing cells and was purified using HPLC. Two active substances were isolated and their sequences were determined as GPTSECFWKYCV and GPPSECFWKYCV, which were revealed to be porcine UII. Synthetic UII peptides caused arachidonic acid metabolites release activity in the rat SENR-expressing cells with an EC(50) value of 1 nM. Three cDNAs encoding the precursor proteins of porcine UII were cloned from a porcine spinal cord cDNA library; 2 consist of 121 amino acid residues and the other, which seemed to be a splicing variant, consist of 85 residues.

ETS-1 converts endothelial cells to the angiogenic phenotype by inducing the expression of matrix metalloproteinases and integrin beta3

The transcription factor ETS-1 is induced in endothelial cells (ECs) by angiogenic growth factors and the specific elimination of ETS-1 synthesis by antisense oligodeoxynucleotide inhibited angiogenesis in vitro (Iwasaka et al., 1996, J Cell Physiol 169:522-531). To understand the precise role of ETS-1 in angiogenesis, we established both high and low ETS-1 expression EC lines and compared angiogenic properties of these cell lines with those of the parental murine EC line, MSS-31. Although growth rate was almost identical for each cell line, the invasiveness was markedly enhanced in high ETS-1 expression cells and reduced in low ETS-1 expression cells compared with that of parental cells. The gene expressions of matrix metalloproteinases (MMP-1, MMP-3, and MMP-9) and gelatinolytic activity of MMP-9 were significantly increased in high ETS-1 expression cells. Low ETS-1 expression cells could not spread on a vitronectin substratum, and the phosphorylation of focal adhesion kinase was markedly impaired because of the reduced expression of integrin beta3. These results indicate that ETS-1 is a principal regulator that converts ECs to the angiogenic phenotype.

Use of a murine monoclonal antibody for detection of circulating plasma DF3 antigen levels in breast cancer patients

The murine monoclonal antibody (MAb), designated DF3, reacts with a 300,000-mol wt mammary epithelial antigen. A sequential double-determinant radioimmunoassay (RIA) has been developed to monitor circulating DF3 antigen. Using this assay, we have demonstrated that 33 of 36 normal women had plasma RIA antigen levels less than 150 U/ml. In contrast, 33 of 43 patients (76%) with metastatic breast cancer had RIA DF3 antigen levels greater than or equal to 150 U/ml. The difference between these two groups was statistically significant (P less than 0.001). Similar results have been obtained with a double-determinant enzyme-linked immunoassay (EIA). Only 6 of 111 age-matched normal subjects had EIA DF3 antigens levels greater than or equal to 30 U/ml, while 42 of 58 patients (72%) with breast cancer had levels equal to or above this value. Thus, similar patterns of specificity are obtained with the EIA or RIA. The elevation of circulating DF3 antigen levels in breast cancer patients has been confirmed by transfer blot assays. MAb DF3 reactivity occurred predominantly with circulating antigens of three different molecular weights ranging from 300,000 to approximately 400,000 mol wt. We also demonstrate that patients with both primary and metastatic breast cancer who were free of detectable disease at the time of sampling have DF3 antigen levels that are similar to those obtained from normal subjects. While patients with hepatoma (27%) and ovarian carcinoma (47%) also had elevated circulating DF3 antigen levels, the results suggest that DF3 antigen levels may be useful in distinguishing breast cancer patients from those with esophageal, gastric, colorectal, pancreatic, and lung carcinomas. Furthermore, the results of the RIA, EIA, and transblot analyses demonstrate that the measurement of circulating DF3 antigen levels provides a new and potentially useful marker to follow the clinical course of patients with metastatic breast cancer.