Interferon-kappa, a novel type I interferon expressed in human keratinocytes.

High throughput cDNA sequencing has led to the identification of interferon-kappa, a novel subclass of type I interferon that displays approximately 30% homology to other family members. Interferon-kappa consists of 207 amino acids, including a 27-amino acid signal peptide and a series of cysteines conserved in type I interferons. The gene encoding interferon-kappa is located on the short arm of chromosome 9 adjacent to the type I interferon gene cluster and is selectively expressed in epidermal keratinocytes. Expression of interferon-kappa is significantly enhanced in keratinocytes upon viral infection, upon exposure to double-stranded RNA, or upon treatment with either interferon-gamma or interferon-beta. Administration of interferon-kappa recombinant protein imparts cellular protection against viral infection in a species-specific manner. Interferon-kappa activates the interferon-stimulated response element signaling pathway and a panel of genes similar to those regulated by other type I interferons including anti-viral mediators and transcriptional regulators. An antibody that neutralizes the type I interferon receptor completely blocks interferon-kappa signaling, demonstrating that interferon-kappa utilizes the same receptor as other type I interferons. Interferon-kappa therefore defines a novel subclass of type I interferon that is expressed in keratinocytes and expands the repertoire of known proteins mediating host defense.

In vivo inhibition of Fas ligand-mediated killing by TR6, a Fas ligand decoy receptor.

TR6, a member of the tumor necrosis factor (TNF) receptor superfamily, has recently been shown to bind to Fas ligand (FasL) and inhibit FasL-mediated cell killing in vitro. In the current study, we demonstrate that TR6 can block the lethal activity of FasL in multiple in vitro systems, and extend this finding to an in vivo model of hepatitis. The binding of human TR6 to human FasL was verified with BIAcore chip technology. Human primary hepatocytes, HT-29 cells and Jurkat cells were assayed for viability to demonstrate TR6 inhibition of FasL-mediated cytotoxicity in vitro. Human TR6 was also shown to cross-react with membrane-bound mouse FasL, since the in vitro cytotoxic activity of L929 cells transfected with murine FasL was inhibited in the presence of human TR6. In vivo, FasL-induced acute, lethal, fulminant hepatic apoptosis resulting in death within 2 h of intravenous injection into Fas+ mice, but not Fas- MRL/lpr mice. Pretreatment of mice with TR6 blocked FasL-induced mortality, presumably by attenuating FasL-induced hepatic apoptosis. Thus, in both in vitro and in vivo systems, TR6 acts as a functional FasL decoy receptor and may be clinically useful in the treatment of hepatitis and other diseases associated with FasL-mediated tissue injury.

Tumor necrosis factor (TNF) receptor superfamily member TACI is a high affinity receptor for TNF family members APRIL and BLyS.

An expression cloning approach was employed to identify the receptor for B-lymphocyte stimulator (BLyS) and identified the tumor necrosis factor receptor superfamily member TACI as a BLyS-binding protein. Expression of TACI in HEK293T cells confers on the cells the ability to bind BLyS with subnanomolar affinity. Furthermore, a TACI-Fc fusion protein recognizes both the cleaved, soluble form of BLyS as well as the membrane BLyS present on the cell surface of a recombinant cell line. TACI mRNA is found predominantly in B-cells and correlates with BLyS binding in a panel of B-cell lines. We also demonstrate that TACI interacts with nanomolar affinity with the BLyS-related tumor necrosis factor homologue APRIL for which no clear in vivo role has been described. BLyS and APRIL are capable of signaling through TACI to mediate NF-kappaB responses in HEK293 cells. We conclude that TACI is a receptor for BLyS and APRIL and discuss the implications for B-cell biology.

A family of chromatin remodeling factors related to Williams syndrome transcription factor.

Chromatin remodeling complexes have been implicated in the disruption or reformation of nucleosomal arrays resulting in modulation of transcription, DNA replication, and DNA repair. Here we report the isolation of WCRF, a new chromatin-remodeling complex from HeLa cells. WCRF is composed of two subunits, WCRF135, the human homolog of Drosophila ISWI, and WCRF180, a protein related to the Williams syndrome transcription factor. WCRF180 is a member of a family of proteins sharing a putative heterochromatin localization domain, a PHD finger, and a bromodomain, prevalent in factors involved in regulation of chromatin structure.

BLyS: member of the tumor necrosis factor family and B lymphocyte stimulator.

The tumor necrosis factor (TNF) superfamily of cytokines includes both soluble and membrane-bound proteins that regulate immune responses. A member of the human TNF family, BLyS (B lymphocyte stimulator), was identified that induced B cell proliferation and immunoglobulin secretion. BLyS expression on human monocytes could be up-regulated by interferon-gamma. Soluble BLyS functioned as a potent B cell growth factor in costimulation assays. Administration of soluble recombinant BLyS to mice disrupted splenic B and T cell zones and resulted in elevated serum immunoglobulin concentrations. The B cell tropism of BLyS is consistent with its receptor expression on B-lineage cells. The biological profile of BLyS suggests it is involved in monocyte-driven B cell activation.

Potent and selective bicyclic lactam inhibitors of thrombin: Part 3: P1' modifications.

The synthesis and antithrombotic activity of a series of nonpeptide bicyclic thrombin inhibitors are described. We have explored the SAR around the P1' site. Modification of the P1' site has been found to affect potency and selectivity.

Evidence that badnavirus infection in Musa can originate from integrated pararetroviral sequences.

When some virus- and disease-free Musa spp. (banana and plantain) are propagated by tissue culture, the resulting plants develop infections with banana streak badnavirus (BSV), a pararetrovirus. In sharp contrast to the virion DNA recovered from natural infections, the virion DNA from tissue culture-associated infections of different Musa spp. was highly similar if not identical. Although BSV does not employ integration during the infection cycle, BSV DNA was found to be integrated into the Musa genome. While one integration consisted of a partial BSV genome, a second contained more than one complete genome that was almost identical to BSV recovered from tissue culture-derived plants. The arrangement of this integrated BSV DNA suggests that it can yield an infectious episomal genome via homologous recombination. This report documents the first instance of integrated DNA of a nonintegrating virus giving rise to an episomal viral infection and identifies tissue culture as a possible trigger for the infection, raising the question of whether similar activatable viral sequences exist in the genomes of other plants and animals.

Characterization of the interferon regulatory factor-7 and its potential role in the transcription activation of interferon A genes.

The family of interferon regulatory factors (IRFs) plays an important role in modulating cellular responses to viral infection and cytokines, including IFNs. The transcription factors that are involved in the transcriptional activation of the IFNB gene have been extensively studied. However, the molecular mechanism by which virus activates the expression of the IFNA gene remains to be defined. Recently, we have identified a new IRF-7 isoform, denoted as IRF-7H, which encodes a protein of 514 amino acids and is most closely related to the IRF-3. The expression of IRF-7 is restricted to the lymphoid cell types and is inducible by virus, lipopolysaccharide, and IFNA. The functional characterization of IRF-7H reveals a presence of transactivation domain located carboxyl-terminal to its DNA binding domain. Overexpression of IRF-7H results in an activation of IFNA promoter in transient transfection assay and a strong enhancement of virus-mediated activation of this promoter. Whereas in uninfected cells, overexpressed IRF-7H is present mainly in the cytoplasm, viral infection facilitates the transfer of IRF-7H to the nucleus; overexpression of IRF-3 interferes with the virus-induced translocation of IRF-7H. Thus, IRF-7 exhibits functional similarity to IRF-3; however, the preferential expression of IRF-7 in lymphoid cells (the cell type that expresses IFNA) suggests that IRF-7 may play a critical role in regulating the IFNA gene expression.

Aortic smooth muscle cells interact with tenascin-C through its fibrinogen-like domain.

The extracellular matrix protein tenascin-C is a multidomain protein that regulates cell adhesion. We used two different smooth muscle cell subtypes derived from adult and newborn rat aorta to investigate the interaction of tenascin-C or its various domains with these cells using an adhesion assay. Newborn cells were three times more adherent to tenascin-C than adult cells. Tenascin C-adhering cells remained round, whereas they spread rapidly on a fibronectin substrate. Adhesion assays showed the interaction between tenascin-C and newborn cells to be predominantly RGD-independent. Mg2+ increased newborn cell adhesion to tenascin-C in a concentration-dependent manner, whereas Ca2+ had no effect. To analyze the structure-function relationships of different domains of tenascin-C, we used recombinant full-length fibronectin-like and fibrinogen-like domains and various subdomains corresponding to the alternatively spliced regions of tenascin-C. The cells adhered to the fibrinogen-like domain but not to the fibronectin-like domain or its subdomains. As with the intact tenascin-C molecule, adherent cells remained round, and the Mg2+, but not Ca2+, promoted this interaction. The interaction of cells with the fibrinogen-like region was further mapped to a 30-amino acid peptide located near the carboxyl-terminal part of the tenascin-C molecule. The same 30-amino acid peptide was active in promoting cell migration. Our results provide a basis for understanding the mechanism of interaction of tenascin-C with smooth muscle cells and a framework for isolating membrane binding sites that mediate the cellular responses to this molecule.

Stimulation of rat vascular smooth muscle cell glycosaminoglycan production by angiotensin II.

Matrix production by smooth muscle cells (SMC) appears to play a major role in the intimal thickening process. Proteoglycans (PG) are the predominant extracellular matrix component of early restenotic lesions. As angiotensin II (A II) has been proposed as a mediator of restenotic process, we hypothesized that A II may directly affect PG synthesis by SMC. SMC were cultured in the presence of [35S]sulfate and angiotensin II, and both the secreted and membrane-bound proteoglycans were analyzed. A II (1 to 100 nM) evoked a dose- and time-dependent increase in both cell- and media-associated PG production, an effect abrogated by the A II receptor antagonist, saralasin. SMC constitutively synthesize small amounts of PG with a molecular mass of 170-250 kDa. After treatment with A II, the abundance of PG is increased, as well as its molecular mass (230-300 kDa). Selective degradation by chondroitinases and heparinase identified chondroitin and dermatan sulfate PG as the predominant form being induced. These results demonstrate that the effect of A II is not general and is specific to certain classes of PGs. In order to further examine the specificity of the A II effect, we compared the synthesis of PG induced by A II with that induced by platelet-derived growth factors AA and BB (PDGF-AA and -BB), insulin-like growth factor I (IGF-I), and tumor necrosis factor alpha (TNF alpha). This comparison demonstrated that the profile of PG induced by A II is different from the other factors examined. Taken together, these data indicate that A II may not only function as a hypertrophic factor for SMC, but in addition may also be a potent modulator of specific PG synthesis by these same cells, which could significantly contribute to the formation of atherosclerotic and restenotic lesions.

Cloning and characterization of alternatively spliced isoforms of rat tenascin. Platelet-derived growth factor-BB markedly stimulates expression of spliced variants of tenascin mRNA in arterial smooth muscle cells.

To understand the alteration of extracellular matrix composition evoked by chemotactic factors, we have studied the expression of adhesive (fibronectin) and anti-adhesive (tenascin) proteins in response to platelet-derived growth factor-BB (PDGF-BB), a potent chemoattractant for rat aortic smooth muscle cells (ASMC). PDGF-BB markedly induced two major tenascin mRNA transcripts, whereas fibronectin mRNA levels did not change. The results of immunoprecipitation studies paralleled Northern blot data. Since alternative splicing is responsible for the generation of multiple tenascin mRNAs in other cell types, we studied the effect of chemotactic factors on the relative abundance of tenascin isoforms. The alternatively spliced region of ASMC-derived rat tenascin was amplified and the identity of the products confirmed by sequencing. Three major polymerase chain reaction products were detected: a 1727-base pair unspliced form which was maximal at 2 h and 635- and 362-base pair products which were more abundant at 8 h after treatment with PDGF-BB or angiotensin II. Functional studies showed that the unspliced isoform of human tenascin inhibited attachment of both human and rat ASMC to fibronectin. These results suggest that PDGF-BB markedly up-regulates the expression of tenascin variants, which may lead to destabilization of cell-matrix interactions and promotion of cell migration.

Angiotensin II regulates tenascin gene expression in vascular smooth muscle cells.

Angiotensin II, a vasoactive peptide, has been implicated in the pathophysiology of a number of vascular wall abnormalities. Since aberrant extracellular matrix deposition contributes to the pathogenesis of vessel wall disease, we examined the potential involvement of angiotensin II in the regulation of extracellular matrix synthesis by vascular smooth muscle cells. Immunoprecipitation of newly synthesized matrix proteins showed that, under serum-free conditions, cultured vascular smooth muscle cells constitutively produced high levels of fibronectin, small amounts of laminin, and a barely detectable amount of tenascin. Angiotensin II treatment increased synthesis of a 230-kDa tenascin glycoprotein by 9-fold and fibronectin synthesis by only 30-40% during a 24-h treatment period, without stimulating laminin production or a general increase in the synthesis of secreted proteins. Concomitant treatment with saralasin, a competitive inhibitor of angiotensin II, prevented the stimulation observed with angiotensin II. The stimulation of immunoprecipitable tenascin was preceded by an increase in tenascin mRNA. Levels of tenascin transcripts (8.4 and 7.0 kilobase) were significantly increased within 2 h after angiotensin II treatment, reached a maximum (10- to 12-fold) by 4 h, and remained elevated after 18 h. The induction was completely blocked by actinomycin D. Serum also induced tenascin mRNA, but with a different time course. Serum induction of tenascin mRNA was also evident at 2 h, maximal at 4 h, but declined to control levels at 8 h. These results indicate that angiotensin II exerts a rapid and selective stimulation of tenascin biosynthesis, at least in part at a transcriptional level. This suggests that angiotensin II may alter the composition of the extracellular matrix of the vessel wall by stimulating synthesis of the antiadhesive protein tenascin.

Peritonitis rates for CAPD patients using the SCD 210 (Inpersol sterile connecting device): a Canadian survey.

A retrospective study was conducted in 20 Canadian hospitals to assess peritonitis rates of CAPD patients utilizing the SCD 210 patient assist device during a 30 month study period. A total of 175 patients having a cumulative SCD experience of 1,494 patient months were included in the survey. Sixty-eight patients experienced 116 episodes of peritonitis, i.e., one episode every 12.9 patient months (pt mo). Patients that had used the SCD for their entire CAPD experience had a significantly lower peritonitis rate (1/15.2 pt mo) compared to patients who had used other CAPD systems (1/10.1 pt mo). Peritonitis rates for diabetic study patients or patients with impaired vision and/or dexterity were not significantly greater than non-diabetic or non-impaired study patients. Staphylococcus epidermidis and Staphylococcus aureus were the most frequent causative microorganisms, accounting for 27.7% and 16.0% of peritonitis episodes caused by single organisms, respectively. The proportion of peritonitis caused by skin commensals was consistent across all study patients, regardless of impairment of vision and/or dexterity. The study results demonstrate the successful application of this patient assist device in a CAPD population that consisted of a large proportion of high risk patients.

The adjuvant effect of stearyl tyrosine on a recombinant subunit hepatitis B surface antigen.

We describe the enhancement of the antibody response against hepatitis B surface Ag by octadecyl L-tyrosine, a synthetic adjuvant designed to exert its adjuvant effect in a manner similar to that of alum because it binds soluble Ag and releases it slowly from the site of injection. Our data demonstrate that octadecyl L-tyrosine showed a significant enhancement of the antihepatitis B surface Ag response compared to that of alum in the secondary response. The most striking difference between octadecyl L-tyrosine and alum in the antihepatitis B surface Ag antibody response was the absence of IgE-specific antibodies subsequent to immunization of the Ag in octadecyl L-tyrosine. Both the optical isomers of the octadecyl esters of tyrosine were adjuvant active, however, the racemic mixture showed a significantly lowe adjuvant activity. This adjuvant has great potential to be used in humans because it is devoid of side effects as assessed by the lack of acute and chronic toxicity in mice and rats, pyrogenicity in rabbits, formation of granuloma in cats, and adjuvant arthritis in rats.

Depression and body image following mastectomy and lumpectomy.

A twenty year debate about the appropriate surgery for breast cancer has resulted in two clinical trials comparing radical vs more conservative operations. Despite the favorable results of these trials, the majority of breast cancer patients in North America still undergo mastectomy. We investigated the psychological and social adjustment following total and partial mastectomy in a group of patients randomly assigned to one or the other operation (National Surgical Adjuvant Breast Protocol--B-06). Total mastectomy patients showed higher levels of depression and less satisfaction with body image. Partial mastectomy patients did not display any measurable increase in fear of recurrence. Patients undergoing radiation therapy showed surprising increase in depressive symptoms. Radiation therapy could well be more frightening to breast surgery patients than had been anticipated. These patients may benefit from some anticipatory counselling.

Prostaglandins. A review of neurophysiology and psychiatric implications.

This article reviews the function of prostaglandins (PGs) in the nervous system and discusses the possible alterations in PG metabolism as relating to mental illness. The PGs are a unique group of cyclic fatty acids whose immediate precursors are thought to function postsynaptically by inhibition or facillitation of neurotransmission through cyclase inhibition or activation, and by means of a negative feedback loop to inhibit further release of neurotransmitter from the presynaptic nerve. A review of PGs in psychiatric conditions is presented as well as a discussion of the interaction of psychoactive drugs with the PGs. The concluding section of this review discusses possible future strategies to provide insight into PG physiology as it relates to synaptic transmission in normal and pathological conditions in man.

Prostaglandin F in patients with primary affective disorder.

Two aspects of prostaglandin F (PGF) metabolism were assessed in patients with primary affective disorder. For a group of hospitalized patients cerebrospinal fluid PGF was measured by radioimmunoassay and the effects of probenecid and L-tryptophan were determined. For outpatients attending our Lithium Clinic, plasma PGF was measured and the acute and chronic effects of lithium were determined. The results of the studies reveal apparently normal concentrations of PGF in cerebrospinal fluid. These concentrations increase twofold after probenecid, indicating that PGF is transported out of the central nervous system by a probenecid-sensitive active transport system. Evidence for inhibition of PGF synthesis during L-tryptophan treatment was found. The results for outpatient plasma studies suggest no effect on PGF with 12 weeks of lithium treatment, although a slight elevation of plasma PGF with chronic lithium treatment may occur. Specificity of the assay technique as applied to plasma is discussed. This is the first report of the direct measurement of PGF in a psychiatric disorder.