Effect of heparin on apoptosis in human nasopharyngeal carcinoma CNE2 cells

In order to study the mechanism of the effect of heparin on apoptosis in carcinoma cells, the nasopharyngeal carcinoma cell line CNE2 was used to identify the effect of heparin on apoptosis associated with the expression of c-myc, bax, bcl-2 proteins by use of Hoechst 33258 staining, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL), agarose gel electrophoresis, and flow cytometry, as well as Western blot analysis. The results showed that heparin induced apoptosis of CNE2 cells including the morphologic changes such as reduction in the volume, and the nuclear chromatin condensation, as well as the "ladder pattern" revealed by agarose gel electrophoresis of DNA in a concentration-dependent manner. The number of TUNEL-positive cells was dramatically increased to 33.6+/-1.2% from 2.8+/-0.3% by treatment with heparin in different concentrations (10 to approximately 40 kU/L). The apoptotic index was increased to 32.5% from 3.5% by detecting SubG1 peaks on flow cytometry. Western blot analysis showed that levels of bcl-2, bax and c-myc were significantly overexpressed by treatment with the increase of heparin concentrations. These results suggest that heparin induces apoptosis of CNE2 cells, which may be regulated by differential expression of apoptosis-related genes.

[Identification and cloning of a novel full ORF gene of P. falciparum PDZ domain containing protein]

OBJECTIVE

To identify and clone a novel full ORF gene of P. falciparum PDZ domain containing protein (PfPCP) and study its expression at the erythrocytic stage.

METHODS

The primers were designed according to the sequences from P. falciparum genomic database. The full ORF gene of PfPCP was amplified from mRNA of the erythrocytic stage of P. falciparum Hainan strain by RT-PCR. Bio-informatics software were used to analyze PfPCP; PfPCP expression at the erythrocytic stage was studied with Western Blotting.

RESULTS

The full ORF gene of PfPCP was 2,076 bp and encoded 691 amino acids. PfPCP contained the typical PDZ domain. Western blotting showed that PfPCP was expressed at the schizont sub-stage of P. falciparum erythrocytic stage.

CONCLUSIONS

The novel full ORF gene of PfPCP is cloned. As a PDZ domain containing protein, PfPCP is expressed at the schizont sub-stage of P. falciparum.

Suppression of autoimmune neuritis in IFN-gamma receptor-deficient mice

Experimental autoimmune neuritis (EAN) is an animal model of the human disease Guillain-Barré syndrome. In this autoimmune inflammatory disease, CD4(+) T cells mediate demyelination in the peripheral nervous system (PNS). Infiltrating macrophages and T cells as well as cytokines like interferon (IFN)-gamma are intimately involved in causing pathogenic effects. To investigate the role of IFN-gamma in cell-mediated EAN, IFN-gamma receptor-deficient mutant (IFN-gammaR(-/-)) C57BL/6 mice and corresponding wild-type mice were immunized with P0 peptide 180-199, a purified component of peripheral nerve myelin, and Freund's complete adjuvant. IFN-gammaR(-/-) mice exhibited later onset of clinical disease. The disease was also less severe than in wild-type mice. Fewer IL-12-producing but more IL-4-producing cells were found in sciatic nerve sections from IFN-gammaR(-/-) mice than from wild-type mice on day 24 postimmunization, i.e., at the peak of clinical EAN. At the same time, IFN-gammaR(-/-) mice had less infiltration of inflammatory cells, including macrophages, CD4(+) T cells, and monocytes, into sciatic nerve tissue and less demyelination. However, numbers of IFN-gamma-secreting cells from the spleen were significantly augmented in the IFN-gammaR(-/-) mice, reflecting a failure of negative feedback circuits. The IFN-gammaR deficiency did not affect the production of anti-P0 peptide 180-199-specific antibodies. These results indicate that IFN-gamma contributes to a susceptibility for EAN in C57BL/6 mice by promoting a Th1 cell-mediated immune response and suppressing a Th2 response.

IL-17 and IFN-gamma mRNA expression is increased in the brain and systemically after permanent middle cerebral artery occlusion in the rat

Brain ischemia is characterized by local inflammation reflected by accumulation of inflammatory cells and a multitude of mediators. Among them, cytokines and chemokines may influence the inflammatory cascade that follows cerebral ischemia. Here we report on brain hemispheric and systemic increase of pro-inflammatory IL-17 and IFN-gamma, the anti-inflammatory cytokines IL-4 and IL-10, and the chemokines IP-10, IL-8 and MIP-2, 1 h to 6 days after permanent middle cerebral artery occlusion (pMCAO). IL-17 and IFN-gamma mRNA levels were elevated in the ischemic hemispheres of pMCAO-operated rats compared with corresponding hemispheres of sham-operated rats. Levels were slightly elevated at 1 h, and peaked at 6 days after pMCAO. IL-8 and MIP-2 levels in the ischemic hemispheres peaked at 24 h, whereas IP-10 showed a biphasic profile with two peaks at 6 h and 6 days after pMCAO. IL-4 peaked in the ischemic hemispheres at 6 h, when IL-10 levels were lower than in sham-operated rats, and IL-10 levels peaked at 2 days after pMCAO. Systemically, the numbers of IL-17 and IFN-gamma mRNA expressing blood mononuclear cells were elevated already at 1 h after pMCAO, preceding the changes in the ischemic hemispheres. Altered levels of IL-17 and IFN-gamma after pMCAO may affect outcome of brain ischemia.

Differential-pulse voltammetric determination of trace formaldehyde using magnetic microspheres and magnetic electrode

A new type of magnetic polymer microsphere containing acylhydrazine groups on the surface was synthesized. They can be reacted with formaldehyde to produce an electroactive adduct. Reduction of these derivatives following aggregation on a magnetic electrode is possible and is effective in the indirect determination of formaldehyde. The experimental conditions and electrode structure are discussed. Under the optimum conditions, it was found that the peak potential (Ep) of formaldehyde is -1.01 V (vs. Ag/AgCl). Formaldehyde in the range 1-1000 micrograms l-1 can be determined. The detection limit for formaldehyde is 0.3 microgram l-1 and the relative standard deviation for the determination of 100 micrograms l-1 formaldehyde was 2.26%. The method was applied to the determination of formaldehyde in environmental samples with satisfactory results.

[Weekly cyclophosphamide pulse therapy combined with corticosteroids in the treatment of pemphigus]

OBJECTIVE

To investigate the better regimen of combined cyclophosphamide pulse therapy with corticosteroids in the treatment of Pemphigus.

METHODS

Intravenous cyclophosphamide was given weekly in a dosage of 600 mg to those Pemphigus patients whose conditions couldn't be improved by corticosteroids (oral prednisone 1.2-1.5 mg/kg/d) alone.

RESULTS

Ten patients with Pemphigus received weekly cyclophosphamide therapy in addition to corticosteroid. Patients conditions improved quickly, without side effects.

CONCLUSIONS

Cyclophosphamide weekly pulse therapy combined with corticosteroids is a good regimen in the treatment of Pemphigus.

CD28-B7 costimulation: a critical role for initiation and development of experimental autoimmune neuritis in C57BL/6 mice

CD28 provides a critical costimulatory signal for antigen-specific T cell activation. Because CD28 is an important factor in the development of autoimmune diseases, we investigated its role in T cell-mediated experimental autoimmune neuritis (EAN), an animal model of Guillain-Barré syndrome in humans. CD28-deficient mutant (CD28-/-) C57BL/6 mice and corresponding wild-type mice were immunized with P0 peptide 180-199, a purified component of peripheral nerve myelin, and Freund's complete adjuvant. As a result, all wild-type mice developed severe EAN, in contrast, none of the CD28-/- mice manifested clinical signs of disease. Additionally, CD28-/- mice had fewer IL-12 producing cells in sciatic nerve sections and fewer IFN-gamma secreting splenic cells than wild-type mice on day 24 post immunization, i.e., at the peak of clinical EAN. At that time point, CD28-/- mice had milder infiltration of such inflammatory cells as macrophages, CD4+ T cells and monocytes into sciatic nerve tissues and less demyelination than wild-type mice. Moreover, the CD28-deficiency led to reduced production of specific anti-P0 peptide 180-199 antibodies compared with wild-type mice. Evidently, CD28 is required for interaction with B7 to regulate the activation of T and B cells that initiates development of EAN.

Pharmacology of caspase inhibitors in rabbit cardiomyocytes subjected to metabolic inhibition and recovery

Protection of ischemic myocardium is an important unmet need in reperfusion therapy of acute myocardial infarction. Myocardial ischemia and reperfusion induce necrosis and apoptosis in cardiomyocytes. Caspase processing and activation are critical steps in most receptor and nonreceptor pathways of apoptosis. Caspase inhibitors have been shown to reduce ischemia reperfusion injury in cardiac muscle. Information about dose response and time of administration are needed to optimize the design of preclinical studies. We used isolated adult rabbit cardiomyocytes subjected to metabolic inhibition (MI) and recovery to examine the role of caspases and caspase inhibitors, the dose response, and the timing of administration. In vitro inhibitory concentrations (Ki) were determined for purified caspases. Cardiomyocytes subjected to MI were treated with peptidomimetic fluoromethyl ketone inhibitors of caspases before or during MI, or at recovery. Caspase inhibitors were most effective when added before MI and included throughout recovery, but were partially protective if added after MI. The optimal concentration of the inhibitors tested was approximately 10 microM. Protection was sustained when cells were allowed to recover for 4 or 24 h. These results suggest that caspase activation is an important component of myocyte injury mediated by MI and recovery. Low doses of caspase inhibitors were identified that reduce injury in this model system, and further investigations using in vivo models are warranted.

The Influence of Bromine Adsorption on Copper Electrodeposition on Polycrystalline Gold Electrodes Modified with Self-Assembled Monolayers

The influence of bromine adsorption on copper electrodeposition on a polycrystalline gold electrode modified with self-assembled monolayers (SAMs) has been investigated by chronoamperometry and cyclic voltammetry. It was found that the deposition potential of copper was shifted negatively due to the SAMs. The hydrogen bond interaction between omega-carboxyl thiols decreased the defect density of the SAMs and significantly retarded the deposition of copper. The presence of bromide anions also shifted the potential more negatively through adsorption into the defects of SAMs. Copyright 2001 Academic Press.

[Effects of insulin on production of NO and NOS mRNA expression in bovine aortic endothelial cells]

AIM

In order to explore the regulation of the production of nitric oxide (NO) and the expression of nitric oxide synthase (NOS) gene in bovine aortic endothelial cells (BAEC) by insulin.

METHODS

The NO2- which is the production of NO in the culture medium was determined based on Griess reaction. Quantitative RT/PCR technique was performed to quantitate the levels of NOS mRNA in BAEC.

RESULTS

(1) Insulin neither affected BAEC proliferation, nor had cytotoxic effect. (2) Over a concentration range of 1-15 microg/ ml, insulin stimulation of BAEC resulted in a dose-dependent production of NO in the culture supernatants 2 hours later, with a maximum at 12 hours and this effect was completely blocked by L-NAME. (3) NOS mRNA was slightly greater in BAEC after exposed to insulin, but without statistical significance.

CONCLUSION

Since the endothelial cell proliferation and the expression of NOS mRNA was not affected with insulin, our data suggested that the insulin-induced NO production was mediated via the activation of NOS activity.

Ontogenesis of proopiomelanocortin and its processing to beta-endorphin by the fetal and neonatal rat brain

A number of reports suggest that beta-endorphin (beta-END) may play an important role in the regulation of cell proliferation and neuronal differentiation. Proopiomelanocortin (POMC), the common precursor ofadrenocorticotropic hormone and beta-END, is detected very early in embryonic life in hypothalamic neurons of the developing rat. However, very little is known about the degree to which POMC is processed to beta-END during fetal and early postnatal life. Thus, it was the objective of the present study to estimate the hypothalamic content of POMC mRNA, as well as the biosynthesis and posttranslational processing of POMC by hypothalamic neurons on fetal day 20 and on days 1, 8 and 22 of postnatal life. Hypothalamic POMC mRNA, as determined by Northern blot analysis, was higher on fetal day 20 than on postnatal days 1, 8 and 22. A higher rate of incorporation of [(3)H]phenylalanine into beta-END immunoreactive peptides was observed on fetal day 20 than on postnatal day 1. However, the rate of incorporation was significantly increased by day 8 of postnatal life and was similar to that on day 22. POMC was processed to beta-lipotropin (beta-LPH) and beta-END at all ages examined, but the relative proportions of POMC:beta-LPH:beta-END changed during development. Thus, beta-END accounted only for 34.89 +/- 6.14% of the total [(3)H]phenylalanine-labeled beta-END immunoreactive peptides on fetal day 20, while it accounted for 57. 37 +/- 5.20, 62.81 +/- 1.38 and 79.25 +/- 6.57% on days 1, 8 and 22 of postnatal life, respectively. Thus, POMC is processed to a considerable extent into beta-END-sized peptides by the fetal hypothalamus and may influence brain development. Furthermore, the rate of processing of hypothalamic POMC into beta-END increases with development, probably due to the increased activity of the enzymes specific for POMC processing.

[Effect of L-dicentrine on contraction of rat stomach muscle strips]

OBJECTIVE

To study the effect of L-dicentrine on the contraction of rat stomach muscle strips induced by 5-HT, histamine K+ and Ca2+.

METHOD

In-vitro experimenting on rat stomach muscle strips.

RESULTS

The contraction of the strips induced by 5-HT histamine K+ and Ca2+ after high K+ depolarization was markedly inhibited by L-dicentrine or papaverine, showing a non-competitive antagonism. The contraction induced by 5-HT was inhibited by L-dicentrine in Ca2+ free solution. L-Dicentrine inhibited the contraction induced by 5-HT, depending on Ca2+ released from the intracellular store. When the Ca2+ concentration in both solutions was restored, L-dicentrine did not influence the contraction significantly.

CONCLUSION

L-Dicentrine could relax the rat stomach smooth muscle. In rat stomach smooth muscles there exist 5-HT receptors.

The contribution of spinal neuronal changes to development of prolonged, tonic nociceptive responses of the cat induced by subcutaneous bee venom injection

To elucidate neurophysiological mechanisms of persistent pain induced by tissue injury, the present study was designed to investigate the effects of s.c. bee venom injection on responses of the dorsal horn nociceptive neurons and those of behavior in anesthetized and awake cats, respectively. A parallel comparative study was also performed to compare the effects of s.c. bee venom and formalin injections on neuronal responses by using an extracellular single-unit recording technique. The present results showed that s.c. bee venom injection into the peripheral cutaneous receptive field resulted in a protracted, tonic monophase of increase in spike responses of wide-dynamic-range (WDR) neurons for more than 1 h, while injection of the same volume of vehicle did not have such an effect. The mean number of spikes during the 60-min period after bee venom was 6.74+/-2.58 spikes/s (n=10), which showed a significant increase in firing rate over the background activity (2.23+/-0.96 spikes/s). Behavioral observations showed that s.c. bee venom injection into the dorsum of a hind paw also produced a prolonged, tonic single phase of response indicative of pain, suggesting that central neuronal changes may contribute to development of bee venom-induced prolonged, tonic pain in cats. The increased neuronal firing induced by s.c. bee venom could be suppressed by a single dose of i.v. morphine and resumed by naloxone. Blockade of the sciatic nerve with lidocaine resulted in a complete suppression of the bee venom-induced neuronal firing, suggesting that the central neuronal changes following s.c. bee venom are peripherally-dependent. Comparative studies showed that the duration and frequency of the bee venom-induced neuronal responses were comparable to those induced by s.c. formalin; however, responses of WDR neurons to mechanical stimuli applied to the injection site of the two chemical agents were quite different. Bee venom produced a significant enhancement of mechanical responses of WDR neurons, while, on the contrary, formalin produced a desensitization of sensory receptors in the injection site, suggesting that the two tonic pain models may have different underlying mechanisms. Copyright 1998 European Federation of Chapters of the International Association for the Study of Pain.

[Effect of jiaweiyiguanjian decoction on hypothalamus-pituitary-thyroid gland (HPT) in rat model with Yin-deficiency of liver and kidney induced by slow irritation]

OBJECTIVE

To explore the mechanism of Jiaweiyiguanjian decoction in nourishing the liver and kidney.

METHOD

A rat model with Yin-deficiency of liver and kidney was made by way of slow irritation. Thyrotropin-releasing-hormone(TRH) of thyron and blood, TSH of pituitary and blood, thyroxine, 3,5,3',5-tetraiodothyronine(FT4) and 3,3',5-traiodothyronine(FT4), 3,3',5-traiodothyronine(rT3) were used as indexes to study the effect of the decoction on HPT.

RESULT

The TRH Secretion from hypothalamus increased (P < 0.05), TSH of pituitary and blood reduced(P < 0.05), FT3 and FT4 of blood decreased at the same time and rT3 of blood, increased. The indexes of the treatment group were found almost the same as the those of the normal control group.

CONCLUSION

Jiaweiyiguanjian Decoction could adjust HPT.

Modulation of early immune responses and suppression of Trypanosoma brucei brucei infections by surgical denervation of the spleen

OBJECTIVE

To examine critical interactions between the nervous system and the immune system during experimental African trypanosomiasis.

METHODS AND RESULTS

Inoculation of Trypanosoma brucei brucei resulted in early interferon (IFN)-gamma production, elevated corticosterone and prostaglandin E(2) (PGE(2)) levels and increased splenocyte proliferation, as measured by enzyme-linked immunospot assay, radioimmunoassay and thymidine incorporation assay, respectively. Splenic denervation suppressed IFN-gamma, corticosterone and PGE(2) production, enhanced splenocyte proliferation, and significantly reduced parasitemia and prolonged rat survival.

CONCLUSIONS

Our data show substantial effects of the nervous system on early immune responses that may influence the outcome of this disease. These effects were not dependent on cytokine inhibitory mediators such as prostaglandins or stress hormones. More investigations are required to understand the evident neural control over the immune system during infectious challenges, which may assist in novel therapeutic approaches.

Comparison of nasal trauma associated with nasopharyngeal airway applied by nurses and experienced anesthesiologists

BACKGROUND

Insertion of a nasopharyngeal airway by nurses is considered to be invasive. We compared the incidence and severity of nasal injury associated with nasopharyngeal airway insertion by trained nurses to those by anesthesiologists to determine the safety of inserting a nasopharyngeal airway by nurses in cardiopulmonary resuscitation (CPR).

METHODS

One hundred and sixteen male and 96 female patients scheduled for general anesthesia were included in the study. The male and female patients were randomly assigned to two groups respectively. Anesthesia was induced with sodium thiopental and fentanyl intravenously. The patients were then ventilated with a bag-valve-mask by trained nurses or anesthesiologists. In the unsuccessfully ventilated patients, nasopharyngeal airways were inserted to facilitate subsequent ventilation. The nasopharyngeal airway, oropharynx, and nostrils were then examined. The incidence and severity of nasal trauma induced by trained nurses or by anesthesiologists were compared.

RESULTS

The study revealed that nasopharyngeal airways applied by trained nurses did not induce more severe nasal trauma than those by anesthesiologists.

CONCLUSION

We suggest that nasopharyngeal airways may be applied safely by trained nurses in CPR.

Proteolysis of synaptobrevin, syntaxin, and SNAP-25 in alveolar epithelial type II cells

Synaptobrevin-2, syntaxin-1, and SNAP-25 were identified in rat alveolar epithelial type II cells by Western blot analysis. Synaptobrevin-2 was localized in the lamellar bodies, and syntaxin-1 and SNAP-25 were found in 0.4% Nonidet P40-soluble and -insoluble fractions, respectively, of the type II cells. When the isolated type II cells were stimulated for secretion with calcium ionophore A23187 or with phorbol 12-myristate 13-acetate, these proteins were found to have been proteolyzed. Preincubation of cells with calpain inhibitor II (N-acetylleucylleucylmethionine), however, prevented the proteolysis. Treatment of the cell lysate with exogenous calpain resulted in a time-dependent decrease of these proteins. The data suggest that synaptobrevin, syntaxin, and SNAP-25 are subject to proteolytic modification by activated calpain in intact type II cells stimulated for secretion.

Activation of the JNK pathway is important for cardiomyocyte death in response to simulated ischemia

Multiple signaling pathways, including the c-Jun N-terminal kinase (JNK) pathway, are activated in myocardial ischemia and reperfusion (MI/R) and correlate with cell death. However, the role of the JNK pathway in MI/R-induced cell death is poorly understood. In a rabbit model, we found that ischemia followed by reperfusion resulted in JNK activation which could be detected in cytosol as well as in mitochondria. To address the functional role of the JNK activation, we examined the consequences of blockade of JNK activation in isolated cardiomyocytes under conditions of simulated ischemia. The JNK activity was stimulated approximately sixfold by simulated ischemia and reperfusion (simulated MI). When a dominant negative mutant of JNK kinase-2 (dnJNKK2), an upstream regulator of JNK, and JNK-interacting protein-1 (JIP-1) were expressed in myocytes by recombinant adenovirus, the activation of JNK by simulated MI was reduced 53%. Furthermore, the TNFalpha-activated JNK activity in H9c2 cells was completely abolished by dnJNKK2 and JIP-1. In correlation, when dnJNKK2 and JIP-1 were expressed in cardiomyocytes, both constructs significantly reduced cell death after simulated MI compared to vector controls. We conclude that activation of the JNK cascade is important for cardiomyocyte death in response to simulated ischemia.

The tyrosine kinases Syk and Lyn exert opposing effects on the activation of protein kinase Akt/PKB in B lymphocytes

The protein kinase Akt/PKB is a crucial regulator of cell survival in response to mitogenic signals. The increased kinase activity of v-akt, an oncogenic form of Akt/PKB, causes mouse T cell lymphoma, and overexpression of Akt/PKB is associated with progression of several tumor types in human. In this study, we demonstrate that ligation of B cell antigen receptor (BCR) leads to activation of Akt/PKB in B lymphocytes. BCR-induced activation of Akt/PKB required the tyrosine kinase Syk, which was not previously known to regulate Akt/PKB. In contrast, BCR crosslinking of Lyn-deficient B cells resulted in markedly enhanced hyperphosphorylation and activation of Akt/PKB compared with wild-type B cells, indicating that this Src-family kinase acts as an endogenous antagonist of BCR-induced Akt/PKB activation. Lyn inhibited Akt/PKB additively with an okadaic acid-sensitive endogenous phosphatase(s). Expression of exogenous Lyn in mutant cells restored normal BCR-induced phosphorylation of Akt/PKB. Negative regulation of Akt/PKB by Lyn was not dependent on the protein phosphatases SHP-1, SHP-2, or SHIP. Our results show that Lyn provides a mechanism for negative regulation and opposes the effect of Syk on BCR-mediated activation of Akt/PKB. Deregulation of Akt/PKB correlates with the hyperresponsiveness of B cells from Lyn-deficient mice stimulated by BCR crosslinking and may contribute to the autoimmune syndrome that develops in Lyn-deficient animals.

The 6-(10-Mercaptodecoxyl)quinoline Self-Assembled Monolayer on Gold: Spectroscopy and Wettability Investigation

A self-assembled monolayer (SAM) with an exposed basic group has been generated by the adsorption of a novel quinoline derivative 6-(10-mercaptodecoxyl)quinoline (MDQ) on a gold surface. The structure and surface properties of the SAMs of MDQ were characterized by ellipsometry, reflection absorption FTIR (RA-IR), and contact angle titration. It was found that the quinoline moiety of MDQ forms an ordered layer on the top of the film and the alkyl chain exhibits a packing density similar to that of a monolayer of decanethiol. The molecular orientation of MDQ in SAMs was evaluated by RA-IR spectroscopy which indicates that the alkyl chain exhibits a tilting angle of 24 +/- 4 degrees with respect to the surface normal and a twisting angle of 50 +/- 5 degrees around its axis. Contact angle titration in the pH range between 2 and 12 illustrates that the surface of SAM of MDQ is less hydrophilic for acidic solution than for basic solution, which is in contrast with the previous reports on SAMs that basic groups are located at the ends of the molecules. Copyright 1999 Academic Press.

The distribution of substance P receptor (NK1)-like immunoreactive neurons in the newborn and adult human spinal cord

Substance P receptor (i.e. NK1)-like immunoreactive (SPR-LI) neurons were observed in the newborn and adult human spinal cord. Substance P receptor-like immunoreactive neuronal cell bodies were seen most frequently in lamina I, and were scattered throughout the remaining laminae of the dorsal horn and the area around the central canal. Some neurons in the intermediolateral nucleus also showed weak immunoreactivity. The pattern of distribution of SPR-LI neurons in the adult spinal cord was essentially the same as that in the newborn spinal cord. However, SPR-LI neurons cell bodies were seen much more frequently in the newborn than in the adult dorsal horn, especially in lamina II.

Characterization of anergic anti-DNA B cells: B cell anergy is a T cell-independent and potentially reversible process

Anti-single stranded DNA (ssDNA) and anti-double stranded DNA (dsDNA) B cells are regulated in non-autoimmune mice. In this report we show that while both anti-ssDNA and anti-dsDNA B cells are blocked in their ability to differentiate into antibody-secreting cells, other phenotypic and functional characteristics distinguish them from one another. Splenic anti-ssDNA B cells are found distributed throughout the B cell follicle, and are phenotypically mature and long-lived. On the other hand, splenic anti-dsDNA B cells are short-lived, exhibit an immature and antigen-experienced phenotype, and localize to the T-B interface of the splenic follicle. Functionally, anti-ssDNA B cells proliferate, albeit suboptimally, in response to anti-IgM, lipopolysaccharide (LPS) and CD40L/IL-4 + anti-IgM stimulation, and tyrosine phosphorylate intracellular proteins upon mIgM cross-linking. Anti-dsDNA B cells, on the other hand, are functionally unresponsive to anti-IgM and LPS stimulation, and do not phosphorylate intracellular proteins, including Syk, upon mIg stimulation. Importantly, anti-DNA B cell anergy is maintained in the absence of T cells since both anti-ssDNA and anti-dsDNA B cells are as efficiently regulated in RAG2(-/-) mice as in their RAG2(+/+) counterparts. Interestingly, the severely anergic state of anti-dsDNA B cells is partially reversible upon stimulation with CD40 ligand and IL-4. In response to these signals, anti-dsDNA B cells remain viable, up-regulate cell surface expression of B7-2 and IgM, and restore their ability to proliferate and phosphorylate Syk upon mIg cross-linking. Collectively, these data suggest that anti-DNA B cell anergy encompasses distinct phenotypes which, even in its most severe form, may be reversible upon stimulation with T cell-derived factors.

Neutralization of macrophage inflammatory protein 2 (MIP-2) and MIP-1alpha attenuates neutrophil recruitment in the central nervous system during experimental bacterial meningitis

Chemokines are low-molecular-weight chemotactic cytokines that have been shown to play a central role in the perivascular transmigration and accumulation of specific subsets of leukocytes at sites of tissue damage. Using in situ hybridization (ISH), we investigated the mRNA induction of macrophage inflammatory protein 2 (MIP-2), MIP-1alpha, monocyte chemoattractant protein 1 (MCP-1), and RANTES. Challenge of infant rats' brains with Haemophilus influenzae type b intraperitoneally resulted in the time-dependent expression of MIP-2, MIP-1alpha, MCP-1, and RANTES, which was maximal 24 to 48 h postinoculation. Immunohistochemistry showed significant increases in neutrophils and macrophages infiltrating the meninges, the ventricular system, and the periventricular area. The kinetics of MIP-2, MIP-1alpha, MCP-1, and RANTES mRNA expression paralleled those of the recruitment of inflammatory cells and disease severity. Administration of anti-MIP-2 or anti-MIP-1alpha antibodies (Abs) resulted in significant reduction of neutrophils. Administration of anti-MCP-1 Abs significantly decreased macrophage infiltration. Combined studies of ISH and immunohistochemistry showed that MIP-2- and MIP-1alpha-positive cells were neutrophils and macrophages. MCP-1-positive cells were neutrophils, macrophages, and astrocytes. Expression of RANTES was localized predominantly to resident astrocytes and microglia. The present study indicates that blocking of MIP-2 or MIP-1alpha bioactivity in vivo results in decreased neutrophil influx. These data are also the first demonstration that the C-C chemokine MIP-1alpha is involved in neutrophil recruitment in vivo.

Suboptimal cross-linking of antigen receptor induces Syk-dependent activation of p70S6 kinase through protein kinase C and phosphoinositol 3-kinase

Ligation of the B cell antigen receptor (BCR) induces a cascade of signaling pathways that lead to clonal expansion, differentiation, or abortive activation-induced apoptosis of B lymphocytes. BCR-mediated cross-linking induces the rapid phosphorylation of protein tyrosine kinases. However, the pathways leading to the activation of downstream serine/threonine kinases such as mitogen-activated protein kinase, p90(Rsk), and p70S6 kinase (p70(S6k)) that mediate reorganization of the actin cytoskeleton, cell cycle progression, gene transcription, and protein synthesis have not been delineated. We recently demonstrated that cross-linking of BCR leads to activation of p70(S6k) in B lymphocytes. In this report, we demonstrate that multiple protein tyrosine kinase-dependent signal transduction pathways induced by BCR lead to the activation of p70(S6k). These distinct pathways exhibit different thresholds with respect to the extent of receptor cross-linking required for their activation. Activation of p70(S6k) by suboptimal doses of anti-Ig is Syk-dependent and is mediated by protein kinase C and phosphoinositol 3-kinase. Moreover, the activation of p70(S6k) results in phosphorylation of S6 protein which is important for ribosomal protein synthesis and may be coupled to BCR-induced protein and DNA synthesis in primary murine B cells.

TRANCE, a TNF family member, is differentially expressed on T cell subsets and induces cytokine production in dendritic cells

TNF-related activation-induced cytokine (TRANCE) is a member of the TNF family recently identified in activated T cells. We report here that TRANCE mRNA is constitutively expressed in memory, but not naive, T cells and in single-positive thymocytes. Upon TCR/CD3 stimulation, TRANCE mRNA and surface protein expression are rapidly up-regulated in CD4+ and CD8+ T cells, which can be further enhanced on CD4+ T cells by CD28-mediated costimulation. However, TRANCE induction is significantly suppressed when cells are stimulated in the presence of IL-4, but is not modified in the presence of IFN-alpha, IFN-gamma, TGF-beta, TNF-alpha, or IL-2. High levels of TRANCE receptor expression are found on mature dendritic cells (DCs). In this study we show that activated T and B cells also express TRANCE receptor, but only at low levels. TRANCE, however, does not exert any significant effect on the proliferation, activation, or survival of those cells. In DCs, TRANCE induces the expression of proinflammatory cytokines (IL-6, IL-1) and T cell growth and differentiation factors (IL-12, IL-15) in addition to enhancing DC survival. Moreover, TRANCE cooperates with CD40 ligand or TNF-alpha to further increase the viability of DCs, suggesting that several TNF-related molecules on activated T cells may cooperatively regulate the function and survival of DCs to enhance T cell-mediated immune responses.

Activation of the p38 mitogen-activated protein kinase pathway by gonadotropin-releasing hormone

Previous studies have shown that interaction of GnRH with its serpentine, G protein-coupled receptor results in activation of the extracellular signal regulated protein kinase (ERK) and the Jun N-terminal protein kinase (JNK) pathways in pituitary gonadotropes. In the present study, we examined GnRH-stimulated activation of an additional member of the mitogen-activated protein kinase (MAPK) superfamily, p38 MAPK GnRH treatment of alphaT3-1 cells resulted in tyrosine phosphorylation of several intracellular proteins. Separation of phosphorylated proteins by ion exchange chromatography suggested that GnRH receptor stimulation can activate the p38 MAPK pathway. Immunoprecipitation studies using a phospho-tyrosine antibody resulted in increased amounts of immunoprecipitable p38 MAPK from alphaT3-1 cells treated with GnRH. Immunoblot analysis of whole cell lysates using a phospho-specific antibody directed against dual phosphorylated p38 kinase revealed that GnRH-induced phosphorylation of p38 kinase was dose and time dependent and was correlated with increased p38 kinase activity in vitro. Activation of p38 kinase was blocked by chronic phorbol ester treatment, which depletes protein kinase C isozymes alpha and epsilon. Overexpression of p38 MAPK and an activated form of MAPK kinase 6 resulted in activation of c-jun and c-fos reporter genes, but did not alter the expression of the glycoprotein hormone alpha-subunit reporter. Inhibition of p38 activity with SB203580 resulted in attenuation of GnRH-induced c-fos reporter gene expression, but was not sufficient to reduce GnRH-induced c-jun or glycoprotein hormone alpha-subunit promoter activity. These studies provide evidence that the GnRH signaling pathway in alphaT3-1 cells includes protein kinase C-dependent activation of the p38 MAPK pathway. GnRH integration of c-fos promoter activity may include regulation by p38 MAPK.

Fabrication and Electrochemical Behavior Investigation of a Polypyrrole/4-Hydroxy-6-methyl-2-mercaptopyrimidine Comodified Gold Electrode

A polypyrrole (PPy)/4-hydroxy-6-methyl-2-mercaptopyrimidine (HMMP) comodified gold electrode was prepared and characterized in the form of PPy/HMMP/Au. The polymerization mechanisms of pyrrole on a bare Au electrode, a dodecanethiol-modified gold electrode, and a HMMP/Au electrode are compared and discussed. With ascorbic acid as a probe, various factors affecting the electrochemical characteristics of the PPy/HMMP/Au electrode are investigated. The catalytic activity for the electrochemical oxidation of l-ascorbic acid was studied in 0.1 mol. L-1 NaCl and 1.0 x 10(-3) mol. L-1 HCl. Both the kinetics of oxidation and the reproducibility of the electrochemical response are enhanced at the comodified electrode compared to that of an unmodified metal electrode or the PPy/Au electrode in determination of ascorbic acid. Copyright 1999 Academic Press.

A molecular basis for the different local anesthetic affinities of resting versus open and inactivated states of the sodium channel

Voltage-gated sodium channels are inhibited by local anesthetic drugs. This inhibition has complex voltage- and frequency-dependent properties, consistent with a model in which the sodium channel has low affinity for local anesthetics when it is in resting states and higher affinity when it is in open or inactivated states. Two residues, a phenylalanine (F1710) and a tyrosine (Y1717), in transmembrane segment IVS6 of the channel alpha subunit are critical for state-dependent block. We examined how these residues determine channel sensitivity to local anesthetics by introducing mutations that varied their size, hydrophobicity, and aromaticity. Block of resting channels by tetracaine was correlated with hydrophobicity at position 1710, as if hydrophobic drug-receptor interactions stabilize binding to resting states. In contrast, drug action on open or inactivated channels required an aromatic residue at this position. We propose that the native phenylalanine at position 1710 stabilizes drug binding to open or inactivated states by either cation-pi or aromatic-aromatic interactions between the aromatic side chain of the amino acid and charged or aromatic moieties on the drug molecule. We also consider the alternative possibility that mutations at this position affect drug action by either altering access to the receptor or by allosteric changes in receptor conformation. Mutations at position 1717 also altered drug action; however, these effects were not well-correlated with the size, hydrophobicity, or aromaticity of the substituted amino acid. These results suggest that the residue at this position does not contribute directly to the drug receptor.

Spatial and temporal expression of c-Fos protein in the spinal cord of anesthetized rat induced by subcutaneous bee venom injection

In order to study central neuronal components involved in subcutaneous (s.c.) bee venom-induced persistent pain (a new tonic pain model), we use Fos immunostaining technique to study the spatial and temporal patterns of neuronal activity in the spinal cord of anesthetized rats. Following intraplantar bee venom injection, Fos-like immunoreactive (ir) neurons were only seen from L1 to S3 rostrocaudally with distinct distribution at L4-5 segments. At segments of L1-2 and S1-3, Fos-ir labelings were diffusely and symmetrically distributed on both sides of the gray matter; however, at L4-5 segments, Fos-ir neurons were densely localized in medial portion of laminae I-II, less densely in laminae V-VI and a few in laminae VII and X ipsilateral to the injection side. No Fos labeling was seen in ventral horn of the spinal cord at L4-5 segments. Fos protein began to express only within lamina I at 0.5 h, but increased over the whole dorsal horn at 1 h and reached peak labeling at 2 h after bee venom. Expression of c-Fos in laminae I-II decreased at 4 h, and completely disappeared at 24 h, however, labeling in laminae V-VI disappeared much slowly and existed even at 96 h after bee venom. Within laminae III-IV, Fos-ir neurons could not be seen at 0.5 h, but began to be seen at 1 h and appeared to exist even at 24 h after bee venom. Systemic morphine suppressed c-Fos expression dose-dependently in both superficial and deep layers of dorsal horn and the latter region was much more sensitive to morphine than the former one. The present results demonstrated that prolonged neuronal activities in superficial and deep layers of dorsal horn were essential to mediation of bee venom induced tonic pain and may have different roles in generation and/or modulation of spontaneous pain and hyperalgesia and allodynia.

Two-dimensional crystallization and projection structure of KcsA potassium channel

Potassium channels are integral membrane proteins that play a crucial role in regulating diverse cell functions in both electrically excitable and non-excitable cells. Molecular cloning has revealed a diverse family of genes that encode these proteins, and a variety of experimental strategies have defined functional domains. We have cloned, over-expressed and purified the KcsA potassium channel to homogeneity and reconstituted this channel protein with phospholipids to form two-dimensional crystals. The crystals belong to plane group p4 and have unit cell dimensions of a=b=48 A. A projection map at 6 A resolution has been obtained by electron crystallography. The map shows that the protein is a homotetramer, having a low-density region on the 4-fold axis that is the site of the ion conduction pathway. Each monomer contains density features that are consistent with the molecular model of a truncated form of KcsA recently determined by X-ray crystallography.

Macrophage apoptosis in muscle tissue in experimental autoimmune myasthenia gravis

Combining in situ tailing and immunocytochemical staining, we demonstrated that the infiltrating macrophages in muscle tissue sections during early phase of experimental autoimmune myasthenia gravis (EAMG) in Lewis rats were eliminated by apoptosis at high frequency. These apoptotic macrophages were colocalized in the end-plate regions. Apoptosis is a major cause for elimination of infiltrating macrophages during the early phase of EAMG.

Inhibition of experimental autoimmune encephalomyelitis in Lewis rats by nasal administration of encephalitogenic MBP peptides: synergistic effects of MBP 68-86 and 87-99

Induction of mucosal tolerance by inhalation of soluble peptides with defined T cell epitopes is receiving much attention as a means of specifically down-regulating pathogenic T cell reactivities in autoimmune and allergic disorders. Experimental autoimmune encephalomyelitis (EAE) induced in the Lewis rat by immunization with myelin basic protein (MBP) and Freund's adjuvant (CFA) is mediated by CD4+ T cells specific for the MBP amino acid sequences 68-86 and 87-99. To further define the principles of nasal tolerance induction, we generated three different MBP peptides (MBP 68-86, 87-99 and the non-encephalitogenic peptide 110-128), and evaluated whether their nasal administration on day -11, -10, -9, -8 and -7 prior to immunization with guinea pig MBP (gp-MBP) + CFA confers protection to Lewis rat EAE. Protection was achieved with the encephalitogenic peptides MBP 68-86 and 87-99, MBP 68-86 being more potent, but not with MBP 110-128. Neither MBP 68-86 nor 87-99 at doses used conferred complete protection to gp-MBP-induced EAE. In contrast, nasal administration of a mixture of MBP 68-86 and 87-99 completely blocked gp-MBP-induced EAE even at lower dosage compared to that being used for individual peptides. Rats tolerized with MBP 68-86 + 87-99 nasally showed decreased T cell responses to MBP reflected by lymphocyte proliferation and IFN-gamma ELISPOT assays. Rats tolerized with MBP 68-86 + 87-99 also had abrogated MBP-reactive IFN-gamma and tumor necrosis factor-alpha mRNA expression in lymph node cells compared to rats receiving MBP 110-128 nasally, while similar low levels of MBP-reactive transforming growth factor-beta and IL-4 mRNA expressing cells were observed in the two groups. Nasal administration of MBP 68-86 + 87-99 only slightly inhibited guinea pig spinal cord homogenate-induced EAE, and passive transfer of spleen mononuclear cells from MBP 68-86 + 87-99-tolerized rats did not protect naïve rats from EAE. Finally, we show that nasal administration of MBP 68-86 + 87-99 can reverse ongoing EAE induced with gp-MBP, although higher doses are required compared to the dosage needed for prevention. In conclusion, nasal administration of encephalitogenic MBP peptides can induce antigen-specific T cell tolerance and confer incomplete protection to gp-MBP-induced EAE, and MBP 68-86 and 87-99 have synergistic effects. Non-regulatory mechanisms are proposed to be responsible for tolerance development after nasal peptide administration.

Dose-dependent mechanisms relate to nasal tolerance induction and protection against experimental autoimmune encephalomyelitis in Lewis rats

Nasal administration of soluble antigens is an exciting means of specifically down-regulating pathogenic T-cell reactivities in autoimmune diseases. The mechanisms by which nasal administration of soluble antigens suppresses autoimmunity are poorly understood. To define further the principles of nasal tolerance induction, we studied the effects of nasal administration of myelin basic protein (MBP) on experimental autoimmune encephalomyelitis (EAE) in the Lewis rat. EAE is a CD4+ T-cell-mediated animal model for human multiple sclerosis. Nasal administration of guinea-pig (gp)-MBP at a dose as low as 30 micrograms/rat can completely prevent gp-MBP-induced EAE, whereas nasal administration of bovine (b)-MBP is not effective even at a much higher dosage. Cellular immune responses, as reflected by T-cell proliferation and interferon-gamma (IFN-gamma)-ELISPOT, were suppressed in rats receiving the two different doses (30 and 600 micrograms/rat) of gp-MBP, but not after administration of b-MBP. Rats tolerized with both doses of gp-MBP had also abrogated MBP-induced IFN-gamma mRNA expression in popliteal and inguinal lymph node mononuclear cells compared with rats receiving phosphate-buffered saline nasally. However, adoptive transfer revealed that only spleen mononuclear cells from rats pretreated with a low dose, but not from those pretreated with a high dose, of gp-MBP transferred protection to actively induced EAE. Low-dose (30 micrograms/rat) gp-MBP-tolerized rats also had high numbers of interleukin-4 (IL-4) mRNA-expressing lymph node cells, while high-dose (600 micrograms/rat) gp-MBP-tolerized rats had low numbers of IL-4 mRNA-expressing lymph node cells. Our data suggest an exquisite specificity of nasal tolerance. Dose-dependent mechanisms also relate to nasal tolerance induction and protection against EAE in the Lewis rat.

Effect of vacuolar proton ATPase on pHi, Ca2+, and apoptosis in neonatal cardiomyocytes during metabolic inhibition/recovery

Recently, we found that vacuolar proton ATPase (VPATPase) operates in cardiomyocytes as a complementary proton-extruding mechanism. Its activity was increased by preconditioning with resultant attenuation of intracellular acidification during ischemia. In this study, we examined whether VPATPase-mediated proton efflux during metabolic inhibition/recovery may spare Na+ overload via Na+-H+ exchange, attenuate Na+-Ca2+ exchange, and decrease apoptosis. Neonatal rat cardiomyocytes were subjected to 2- to 3-hour metabolic inhibition with cyanide and 2-deoxyglucose and 24-hour recovery. The effect of VPATPase inhibition by 50 nmol/L bafilomycin A1 on apoptosis, pHi, and [Ca2+]i was studied by flow cytometry with propidium iodide, seminaphthorhodafluor (SNARF)-1-AM, and indo-1-AM staining, respectively. VPATPase inhibition increased the amount of apoptosis measured after 24 hours of recovery and abrogated the protective effect of inhibition of Na+-H+ exchange by (5-N-ethyl-N-isopropyl)amiloride (EIPA). Dual blockade of VPATPase and Na+-H+ exchange was additive in effect with EIPA on pHi during metabolic inhibition/recovery and recovery from the acid challenge with sodium propionate. VPATPase blockade increased the rate of accumulation of intracellular Ca2+ at the beginning of metabolic inhibition and abrogated the delaying effect of EIPA on intracellular Ca2+ accumulation. These results indicate that VPATPase plays an important accessory role in cardiomyocyte protection by reducing acidosis and Na+-H+ exchange-induced Ca2+ overload.

Nasal tolerance to experimental autoimmune myasthenia gravis: tolerance reversal by nasal administration of minute amounts of interferon-gamma

Tolerance to B cell-mediated experimental autoimmune myasthenia gravis (EAMG), an animal model for myasthenia gravis (MG) in humans, can be achieved by nasal administration of the autoantigen acetylcholine receptor (AChR). Nasal tolerance induction requires only 1/1000 of the amount of AChR used for oral tolerance induction, but is as effective in preventing EAMG. To investigate whether nasally induced tolerance to EAMG can be influenced by nasal administration of cytokines, recombinant rat IFN-gamma (total 5000 U/rat), a combination of AChR and IFN-gamma or AChR alone was given nasally to Lewis rats before immunization with AChR and complete Freund's adjuvant (CFA). One additional group of rats received the same amount of AChR nasally in conjunction with IFN-gamma (total 5000 U/rat) intraperitoneally. AChR given alone nasally induced effective tolerance to EAMG whereas rats receiving AChR + IFN-gamma by the nasal route exhibited a similar disease pattern, and similarly escalated T and B cell responses to AChR when compared to control EAMG rats. In contrast, administration of IFN-gamma i.p. together with AChR nasally did not affect the induction of tolerance to EAMG. IFN-gamma given alone nasally did not affect clinical EAMG. This study demonstrates that nasal tolerance can be modulated by nasal administration of minute amounts of IFN-gamma. Nasal administration of certain cytokines with beneficial effects might broaden the effectiveness of applying nasal tolerance as a potential therapeutic means of preventing autoimmune diseases.

Nasal tolerance in experimental autoimmune myasthenia gravis (EAMG): induction of protective tolerance in primed animals

Nasal administration of microg doses of acetylcholine receptor (AChR) is effective in preventing the development of B cell-mediated EAMG in the Lewis rat, a model for human MG. In order to investigate whether nasal administration of AChR modulates ongoing EAMG, Lewis rats were treated nasally with AChR 2 weeks after immunization with AChR and Freund's complete adjuvant. Ten-fold higher amounts of AChR given nasally (600 microg/rat) were required to ameliorate the manifestations of EAMG compared with the amounts necessary for prevention of EAMG. In lymph node cells from rats receiving 600 microg/rat of AChR, AChR-induced proliferation and interferon-gamma (IFN-gamma) secretion were reduced compared with control EAMG rats receiving PBS only. The anti-AChR antibodies in rats treated nasally with 600 microg/rat of AChR had lower affinity, reduced proportion of IgG2b and reduced capacity to induce AChR degradation. Numbers of AChR-reactive IFN-gamma and tumour necrosis factor-alpha (TNF-alpha) mRNA-expressing lymph node cells from rats treated nasally with 600 microg/rat of AChR were suppressed, while IL-4, IL-10 and transforming growth factor-beta (TGF-beta) mRNA-expressing cells were not affected. Collectively, these data indicate that nasal administration of AChR in ongoing EAMG induced selective suppression of Th1 functions, i.e. IFN-gamma and IgG2b production, but no influence on Th2 cell functions. The impaired Th1 functions may result in the production of less myasthenic anti-AChR antibodies and contribute to the amelioration of EAMG severity in rats treated with AChR 600 microg/rat by the nasal route.

An antisense oligodeoxyribonucleotide to m-calpain mRNA inhibits secretion from alveolar epithelial type II cells

We investigated the effect of translational suppression of m-calpain on [3H]-phosphatidylcholine (PC) secretion utilising an antisense oligodexoyribonucleotide (oligo) directed against mRNA encoding m-calpain catalytic subunit. Two types of oligo, sense (S) and antisense (AS), to a portion of exon 12 of rat m-calpain catalytic subunit mRNA were tested. Constitutive secretion was decreased by 23% by AS-oligo (1 microM) treatment, while S-oligo (1 microM) had no effect. TPA-stimulated secretion was inhibited about 50-60% by AS-oligo (1-3 microM) and the inhibition was concentration-dependent, while S-oligo (1 microM) only inhibited about 10% of TPA-stimulated secretion. Northern and Western blot analyses revealed that the AS-oligo treatment reduced m-calpain mRNA and protein levels by 32% and 78%, respectively. The data indicate that antisense strategy is effective in suppressing calpain expression and type II cell secretion.

Complexities of applying nasal tolerance induction as a therapy for ongoing relapsing experimental autoimmune encephalomyelitis (EAE) in DA rats

EAE is an autoimmune disease of the central nervous system (CNS) that serves as an experimental model for the human inflammatory demyelinating disease multiple sclerosis (MS). Antigen-based immunotherapy including soluble antigen administration via feeding has been shown to be successful in treating EAE in rodents. In the present study, we explore nasal administration of small amounts of myelin basic protein (MBP) as a potential means of treatment of protracted, relapsing EAE (PR-EAE) in a novel DA rat system. We found that nasal administration of MBP prevented EAE induced with whole spinal cord homogenate + Freund's incomplete adjuvant (FIA), and strongly down-regulated levels of MBP-reactive interferon-gamma (IFN-gamma)-secreting Th1-like cells. However, in rats with ongoing PR-EAE receiving the same regimen of MBP, a trend of aggravated disease was recorded, in conjunction with augmented levels of MBP-reactive IFN-gamma-secreting Th1-like splenocytes during the acute phase of EAE. These data have implications for the clinical application of nasal tolerance to autoimmune diseases.

TRANCE (tumor necrosis factor [TNF]-related activation-induced cytokine), a new TNF family member predominantly expressed in T cells, is a dendritic cell-specific survival factor

TRANCE (tumor necrosis factor [TNF]-related activation-induced cytokine) is a new member of the TNF family that is induced upon T cell receptor engagement and activates c-Jun N-terminal kinase (JNK) after interaction with its putative receptor (TRANCE-R). In addition, TRANCE expression is restricted to lymphoid organs and T cells. Here, we show that high levels of TRANCE-R are detected on mature dendritic cells (DCs) but not on freshly isolated B cells, T cells, or macrophages. Signaling by TRANCE-R appears to be dependent on TNF receptor-associated factor 2 (TRAF2), since JNK induction is impaired in cells from transgenic mice overexpressing a dominant negative TRAF2 protein. TRANCE inhibits apoptosis of mouse bone marrow-derived DCs and human monocyte-derived DCs in vitro. The resulting increase in DC survival is accompanied by a proportional increase in DC-mediated T cell proliferation in a mixed leukocyte reaction. TRANCE upregulates Bcl-xL expression, suggesting a potential mechanism for enhanced DC survival. TRANCE does not induce the proliferation of or increase the survival of T or B cells. Therefore, TRANCE is a new DC-restricted survival factor that mediates T cell-DC communication and may provide a tool to selectively enhance DC activity.

Granulocyte colony-stimulating factor upregulates the vacuolar proton ATPase in human neutrophils

We have previously shown that granulocyte colony-stimulating factor (G-CSF ) delays spontaneous neutrophil apoptosis through activation of the vacuolar proton ATPase (v-ATPase). We have now examined the regulation of the v-ATPase in neutrophils exposed to G-CSF in vitro. When neutrophils were cultivated in the absence of G-CSF, the 57-kD cytosolic B subunit of the v-ATPase disappeared within 1 to 2 hours, its loss preceding the nuclear changes of apoptosis and coinciding with the onset of acidification. By contrast, in neutrophils cultured for 2 hours in the presence of G-CSF, the amount of the 57-kD subunit was similar to that in freshly isolated neutrophils. However, inhibition of protein synthesis with cycloheximide and actinomycin D led to loss of the 57-kD subunit even in the presence of G-CSF. These results indicated that ongoing protein synthesis was required to maintain the v-ATPase, and further suggested that G-CSF acted, at least in part, by maintaining synthesis of the 57-kD cytosolic subunit. G-CSF also promoted the translocation of the 57-and 33-kD cytosolic v-ATPase subunits to the membrane. Our findings suggested two coordinate mechanisms by which the activity of the v-ATPase could be increased by G-CSF: the synthesis of cytosolic v-ATPase subunits and their translocation to the membrane.

Nasal administration of myelin basic protein prevents relapsing experimental autoimmune encephalomyelitis in DA rats by activating regulatory cells expressing IL-4 and TGF-beta mRNA

This study explores nasal administration of myelin basic protein (MBP) as a potential means of inducing tolerance to relapsing experimental autoimmune encephalomyelitis (PR-EAE), an experimental multiple sclerosis (MS) model that was induced in DA rats by immunization with rat spinal cord homogenate and incomplete Freund's adjuvant. DA rats received a total dosage of 0, 6, 60, 600 micrograms/rat of bovine MBP on ten consecutive days prior to immunization. EAE with typical course was observed in control rats receiving only PBS nasally, and in rats receiving 6 micrograms/rat of MBP. Rats receiving 60 micrograms/rat of MBP developed acute EAE but no relapse during 60 days of observation post immunization (p.i.). Only one of eight rats receiving 600 micrograms/rat of MBP developed slight, transient EAE. This protection was confirmed at the histology level and was associated with decreased levels of MBP-reactive IFN-gamma secreting Th1-like spleen cells on day 13 and 60 p.i. Rats receiving 60 and 600 micrograms/rat of MBP showed decreased serum anti-MBP IgG2b antibody levels on day 60 p.i., and rats receiving 600 micrograms/rat of MBP had marginally increased anti-MBP IgG1 antibody levels in serum compared to control EAE rats. Cytokine mRNA profiles in central nervous system (CNS) and spleen mononuclear cells were evaluated. Dose-dependent reduction of TNF-alpha mRNA expression were observed both in CNS and in splenocytes. Increased IL-4 and TGF-beta mRNA expression were observed in CNS of low (6 micrograms/rat) and median (60 micrograms/rat) dose of MBP tolerized rats and in splenocytes of rats tolerized with 600 micrograms/rat of MBP. We conclude that nasal administration of MBP in DA rat prevents EAE induced by immunization with whole rat spinal cord homogenate that, besides MBP, contains multiple antigenic myelin proteins. A mechanism involving MBP-reactive regulatory cells expressing IL-4 and TGF-beta mRNA acts as part in the induction of this tolerance.

Syk is required for BCR-mediated activation of p90Rsk, but not p70S6k, via a mitogen-activated protein kinase-independent pathway in B cells

The tyrosine kinases Syk and Lyn are activated in B lymphocytes following antibody induced cross-linking of the B cell receptor for antigen (BCR). It has been suggested that activation of Syk is dependent on Lyn. We tested this hypothesis by comparing the phosphorylation and activation of several downstream effector molecules in parental DT40, DT40Syk- and DT40Lyn- B cells. The phosphorylation and activation of p90Rsk was ablated in Syk-deficient B cells but unaffected in Lyn-deficient B cells while the phosphorylation/activation of Ras GTPase activating protein (Ras GAP) and mitogen activated protein (MAP) kinase required both Syk and Lyn. Thus, these data indicate that Syk can be activated in the absence of Lyn after BCR cross-linking and results in the activation of p90Rsk via a MAP kinase-independent pathway in DT40Lyn- cells. We also demonstrated that BCR mediates the activation of p70S6k. However, activation of p70S6k in DT40Syk- and DT40Lyn- cells was comparable with that observed in parental cells. Thus, either Syk or Lyn may be sufficient for activation of p70S6k, or activation of p70S6k occurs independently of both Syk and Lyn. The kinase activity of Syk was required for the phosphorylation/activation of each of these downstream effector molecules but only the phosphorylation of Ras GAP was affected in cells expressing a mutant of Syk in which tyrosines 525 and 526 were substituted to phenlyalanines.

Inhibition of lung surfactant secretion from alveolar type II cells and annexin II tetramer-mediated membrane fusion by phenothiazines

We investigated the effects of phenothiazines on lung surfactant secretion from rat alveolar epithelial type II cells and on annexin II tetramer (Anx IIt)-mediated membrane fusion. Trifluoperazine and promethazine inhibited ATP-stimulated phosphatidylcholine (PC) secretion from type II cells in a dose-dependent manner. Concentrations that cause 50% inhibition (IC50) were approximately 3 and 25 microM for trifluoperazine and promethazine, respectively. Promethazine also inhibited PC secretion of type II cells stimulated by other secretagogues, including calcium ionophore A23187, phorbol 12-myristate 13-acetate, and terbutaline that are known to stimulate PC secretion via different signal transduction pathways. Since we have recently determined that Anx IIt is involved in PC secretion of type II cells, we examined whether phenothiazines influence Anx IIt's activity. Trifluoperazine and promethazine inhibited Anx IIt's ability to aggregate phosphatidylserine (PS) liposomes, to fuse PS/phosphatidylethanolamine (PE) liposomes, and to fuse PS/PE liposomes with lamellar bodies. These results suggest a relationship between lung surfactant secretion and Anx IIt-mediated membrane fusion.

Defective neurite extension is caused by a mutation in amyloid beta/A4 (A beta) protein precursor found in familial Alzheimer's disease

Clonal central nervous system neuronal cells, B103, do not synthesize detectable endogenous APP or APLP. B103 cells transfected with both wild-type (B103/APP) and mutant APP construct (B103/APP delta NL) secreted comparable amounts of soluble forms of APP (sAPP). B103/APP cells produced sAPP and cleaved at amyloid beta/A4 (A beta) 16, the alpha-secretase site, and B103/APP delta NL cells produced sAPP beta cleaved at A beta 1, the beta-secretase site. B103/APP delta NL cells developed fewer neurites than B103/APP cells in a serum-free defined medium. Neurite numbers of parent B103 cells were increased by the 50% conditioned medium (CM) from B103/APP cells but reduced by the CM from B103/APP delta NL cells. Chemically synthesized A beta at concentration levels higher than 1 nM reduced numbers of neurites from B103 or B103/APP delta NL cells. However, A beta at 1-100 nM could not reduce the neurite number of B103/APP cells. The protective activity against A beta's deleterious effect to reduce neurite numbers was attributed to sAPP alpha in the CM. Although sAPP alpha could block the effect of A beta, sAPP beta could not do so under the identical condition, suggesting the importance of the C-terminal 15-amino acid sequence in sAPP alpha. Nevertheless, sAPP alpha's protective activity required the N-terminal sequence around RERMS, previously identified to be the active domain of sAPP beta. The overall effect of APP mutation which overproduced A beta and sAPP beta and underproduced sAPP alpha was a marked decline in the neurotrophic effect of APP. We suggest that the disruption of balance between the detrimental effect of A beta and the trophic effect of sAPP may be important in the pathogenesis of AD caused by this pathogenic APP mutation.

Drug allergy: identification and characterization of IgE-reactivities to aspirin and related compounds

Twenty-seven patients with aspirin (ASA) sensitivity were studied. 14 patients had naso-ocular-bronchial reactions after taking ASA while others had cutaneous and gastrointestinal reactions. The oral challenges with salicylic acid (SA), O-methylsalicylic acid (OMSA), ASA, and the determination of IgE antibodies specific to salicyloyl, O-methylsalicyloyl, acetylsalicyloyl using correspondent disks by RAST, RAST inhibition and RAST crossinhibition assays were performed. The findings suggest that OMSA seems to be the main offender responsible for cutaneous and gastrointestinal reactions, whereas ASA is responsible for naso-ocular-bronchial reactions. The clinical crossreactions between ASA and ASA-like drugs (nonsteroidal anti-inflammatory drugs and pyrazolone drugs) are probably due to "inborn errors of metabolism". The results indicate that genetic factors, mast-cell heterogeneity, and the interindividual variability in drug metabolism, combined with immunological background should be considered as underlying mechanisms.

Ultraviolet A irradiation upregulates type VII collagen expression in human dermal fibroblasts

Type VII collagen, a major component of skin-anchoring fibrils, is synthesized by both fibroblasts and keratinocytes, the two principal cell types in the skin. In this study, we examined the effects of ultraviolet A (UVA) irradiation on the expression of type VII collagen in human fibroblasts. UVA irradiation (0-15 J/cm2) caused a dose-dependent increase (5- to 10-fold) in type VII collagen mRNA levels as detected by northern blot analysis. The UVA-induced enhancement of type VII collagen gene expression correlated with an increase in its protein level by immunoblot analysis of proteins secreted into the conditioned medium. The effect of UVA was observed at 12 h and reached its maximum by 18 h. Under these conditions, however, the expression of fibronectin, a major dermal matrix protein, remained unchanged, suggesting that the induction of type VII collagen expression was selective. Actinomycin D, a transcription inhibitor, blocked the UVA-mediated induction of type VII collagen gene expression, whereas cycloheximide, a protein synthesis inhibitor, superinduced the expression of type VII collagen, suggesting that de novo protein synthesis was not required for the action of UVA. Interestingly, in contrast to the increased type VII collagen expression in fibroblasts in response to UVA, a slight decrease in type VII collagen mRNA level was observed in the UVA-irradiated keratinocytes, suggesting that the effect of UVA on the type VII collagen expression is cell type specific.