Xanthiosite and aerugite

Two nickel arsenates from South Terras mine, St. Stephen-in-Brannell, Cornwall, have been shown to be identical with the minerals xanthiosite and aerugite, described by C. Bergemann in 1858, and with two synthetic products described by J. B. Taylor and R. D. Heyding (1958). Xanthiosite is pure golden-yellow, monoclinic, with a 10·174, b 9·548, c 5·766 Å, β 92° 58½′, space group P21/a; with D154=5·42±0·10, the unit cell contains 4[Ni3(AsO4)2] (Dcalc 5·388±0·003). Aerugite is deep blue-green, monoclinic, with a 10·29, b 5·95, c 9·79 Å, β 110° 19′, space-group C2, Cm, or C2/m; the ideal unit cell formula is 2[Ni9As3O16], with one-sixth of the arsenic trivalent; the natural mineral has a lower Ni:As ratio, around 2·6. Both xanthiosite and aerugite are minerals new to Britain.

MKP-1 suppresses PARP-1 degradation to mediate cisplatin resistance

Understanding the mechanisms of platinum compound resistance, including cisplatin resistance, has important implications for improving cancer treatments. Previous studies identified a potential role for mitogen-activated protein kinase phosphatase-1 (MKP-1) in cisplatin resistance. This work focuses on the regulation of poly(ADP-ribose) polymerase-1 (PARP-1) expression by MKP-1. We found that MKP-1 overexpression stimulates PARP-1 and poly(ADP-ribose) (PAR) protein expression and cisplatin resistance while its downregulation suppresses PARP-1 and PAR protein expression and cisplatin resistance. Silencing MKP-1 promoted PARP-1 ubiquitination, which decreased PARP-1 protein levels. We also found that silencing c-Jun N-terminal kinase 1/2 (JNK1/2) decreased PARP-1 ubiquitination while increasing total PARP-1 protein levels. Furthermore, we showed that acquired cisplatin resistant ovarian cancer cells expressed the high levels of MKP-1 and PARP-1 proteins, and that silencing MKP-1 or PARP-1 increased cisplatin sensitivity in resistant cells. Notably, the pharmacologic inhibition of PARP activity restored cisplatin sensitivity in MKP-1 overexpressing cells. Thus, this work indicates that suppression of JNK1/2 activity by MKP-1 maintains PARP-1 levels and suggests that MKP-1-mediated cisplatin resistance can be bypassed by PARP-1 inhibition.

Joint analysis of BICEP2/keck array and Planck Data

We report the results of a joint analysis of data from BICEP2/Keck Array and Planck. BICEP2 and Keck Array have observed the same approximately 400  deg^{2} patch of sky centered on RA 0 h, Dec. -57.5°. The combined maps reach a depth of 57 nK deg in Stokes Q and U in a band centered at 150 GHz. Planck has observed the full sky in polarization at seven frequencies from 30 to 353 GHz, but much less deeply in any given region (1.2  μK deg in Q and U at 143 GHz). We detect 150×353 cross-correlation in B modes at high significance. We fit the single- and cross-frequency power spectra at frequencies ≥150  GHz to a lensed-ΛCDM model that includes dust and a possible contribution from inflationary gravitational waves (as parametrized by the tensor-to-scalar ratio r), using a prior on the frequency spectral behavior of polarized dust emission from previous Planck analysis of other regions of the sky. We find strong evidence for dust and no statistically significant evidence for tensor modes. We probe various model variations and extensions, including adding a synchrotron component in combination with lower frequency data, and find that these make little difference to the r constraint. Finally, we present an alternative analysis which is similar to a map-based cleaning of the dust contribution, and show that this gives similar constraints. The final result is expressed as a likelihood curve for r, and yields an upper limit r_{0.05}<0.12 at 95% confidence. Marginalizing over dust and r, lensing B modes are detected at 7.0σ significance.

Epizootics of sudden death in tammar wallabies (Macropus eugenii) associated with an orbivirus infection

Epizootics of sudden death in tammar wallabies (Macropus eugenii) occurred at six research facilities and zoological gardens in New South Wales, Australia, in late 1998 and at one Queensland research facility in March 1999. There were 120 confirmed tammar wallaby deaths during this period; however, population censuses indicated that up to 230 tammar wallabies may have died. The majority of animals died without premonitory signs. A small proportion of wallabies exhibited increased respiratory rate, sat with a lowered head shortly before death or were discovered in lateral recumbency, moribund and with muscle fasciculations. Gross postmortem findings consistently included massive pulmonary congestion, mottled hepatic parenchyma and subcutaneous oedema throughout the hindlimbs and inguinal region. Approximately 30% of the animals examined also had extensive haemorrhage within the fascial planes and skeletal muscle of the hindlimb adductors, inguinal region, ventral thorax, dorsal cervical region and perirenal retroperitoneal area. The tissues of affected animals became autolytic within a short period after death. Bacteriological examination of tissues from 14 animals did not provide any significant findings. Toxicological examination of the gastric and colonic contents of four animals did not reveal evidence of brodifacoume or other rodenticides. Viruses from the Eubenangee serogroup of the Orbivirus genus were isolated from the cerebral cortex of nine, and the myocardium of two, tammar wallabies and the liver and intestine of another tammar wallaby. A similar orbivirus was also isolated from the cerebrospinal fluid of another tammar wallaby that died suddenly. The disease agent appears to be a previously unrecognised orbivirus in the Eubenangee serogroup. This is the first report of epizootics of sudden deaths in tammar wallabies apparently associated with an orbivirus infection.

The first identified case of pandemic H1N1 influenza in pigs in Australia

A 300-sow farrow-to-finish herd in New South Wales was infected with influenza pandemic (H1N1) 2009 (H1N1/09) virus in July 2009 and became the first recorded case of influenza in pigs in Australia. The outbreak resulted from human-to-pig transmission. Clinical signs in affected pigs were mild compared with overseas reports of 'classical' swine influenza virus and included coughing and decreased appetite in a small proportion of non-lactating breeding stock, weaners, growers and finishers. A diagnosis of H1N1/09 influenza virus infection was confirmed using a combination of serology (haemagglutination inhibition, blocking enzyme-linked immunosorbent assay) and real-time reverse transcription polymerase chain reaction. Attempts at virus isolation were unsuccessful. Results of a longitudinal study of pigs on this farm suggested that the virus continued to circulate for 9 weeks after the onset of infection, but was not present 6 months later. This report highlights the difficulties in preventing transmission of H1N1/09 influenza virus from infected humans to pigs during a human pandemic.

Performance of an automated solid-phase red cell adherence system compared with that of a manual gel microcolumn assay for the identification of antibodies eluted from red blood cells

IgG antibodies coating red blood cells (RBCs) can be removed by elution procedures and their specificity determined by antibody identification studies. Although such testing is traditionally performed using the tube agglutination assay, prior studies have shown that the gel microcolumn (GMC) assay may also be used with comparable results. The purpose of this study was to compare an automated solid-phase red cell adherence (SPRCA) system with a GMC assay for the detection of antibodies eluted from RBCs. Acid eluates from 51 peripheral blood (PB) and 7 cord blood (CB) samples were evaluated by both an automated SPRCA instrument and a manual GMC assay. The concordance rate between the two systems for peripheral RBC samples was 88.2 percent (45 of 51), including cases with alloantibodies (n = 8), warm autoantibodies (n = 12), antibodies with no identifiable specificity (n = 2), and negative results (n = 23). There were six discordant cases, of which four had alloantibodies (including anti-Jka, -E, and -e) demonstrable by the SPRCA system only. In the remaining 2 cases, anti-Fya and antibodies with no identifiable specificity were demonstrable by the GMC assay only. All seven CB specimens produced concordant results, showing anti-A (n = 3), -B (n = 1), maternal anti-Jka (n = 2), or a negative result (n = 1). Automated SPRCA technology has a performance that is comparable with that of a manual GMC assay for identifying antibodies eluted from PB and CB RBCs.

Infertility and venereal disease in cattle inseminated with semen containing bovine herpesvirus type 5

A group of 20 cows and heifers experienced poor conception rates and probable ovarian dysfunction after being artificially inseminated. When first examined, some showed signs of vulvovaginitis, with pustular, ulcerative lesions consistent with a herpesvirus infection. They had had no contact with bulls during the current breeding season. Bovine herpesvirus type 5 (BHV-5) was isolated from samples of frozen semen from the batch that had been used for the artificial insemination programme. BHV-5 was also isolated from the semen of a second apparently healthy bull during routine screening of its semen.

Role of MKK3-p38 MAPK signalling in the development of type 2 diabetes and renal injury in obese db/db mice

AIMS/HYPOTHESIS

Obesity and diabetes are associated with increased intracellular p38 mitogen-activated protein kinase (MAPK) signalling, which may promote tissue inflammation and injury. Activation of p38 MAPK can be induced by either of the immediate upstream kinases, MAP kinase kinase (MKK)3 or MKK6, and recent evidence suggests that MKK3 has non-redundant roles in the pathology attributed to p38 MAPK activation. Therefore, this study examined whether MKK3 signalling influences the development of obesity, type 2 diabetes and diabetic nephropathy.

METHODS

Wild-type and Mkk3 (also known as Map2k3) gene-deficient db/db mice were assessed for the development of obesity, type 2 diabetes and renal injury from 8 to 32 weeks of age.

RESULTS

Mkk3 (+/+) db/db and Mkk3 (-/-) db/db mice developed comparable obesity and were similar in terms of incidence and severity of type 2 diabetes. At 32 weeks, diabetic Mkk3 (+/+) db/db mice had increased kidney levels of phospho-p38 and MKK3 protein. In comparison, kidney levels of phospho-p38 in diabetic Mkk3 ( -/- ) db/db mice remained normal, despite a fourfold compensatory increase in MKK6 protein levels. The reduced levels of p38 MAPK signalling in the diabetic kidneys of Mkk3 ( -/- ) db/db mice was associated with protection against the following: declining renal function, increasing albuminuria, renal hypertrophy, podocyte loss, mesangial cell activation and glomerular fibrosis. Diabetic Mkk3 ( -/- ) db/db mice were also significantly protected from tubular injury and interstitial fibrosis, which was associated with reduced Ccl2 mRNA expression and interstitial macrophage accumulation.

CONCLUSIONS/INTERPRETATION

MKK3-p38 MAPK signalling is not required for the development of obesity or type 2 diabetes, but plays a distinct pathogenic role in the progression of diabetic nephropathy in db/db mice.

BGC20-1531, a novel, potent and selective prostanoid EP receptor antagonist: a putative new treatment for migraine headache

BACKGROUND AND PURPOSE

Prostanoid EP(4) receptor antagonists may have therapeutic utility in the treatment of migraine since EP(4) receptors have been shown to be involved in prostaglandin (PG)E(2)-induced cerebral vascular dilatation, which may be an important contributor to migraine pain. This study reports the pharmacological characterization of BGC20-1531, a novel EP(4) receptor antagonist.

EXPERIMENTAL APPROACH

BGC20-1531 was characterized in radioligand binding and in vitro functional assays employing recombinant and native EP(4) receptors. Changes in canine carotid haemodynamics were used to assess the pharmacodynamic profile of BGC20-1531 in vivo.

KEY RESULTS

BGC20-1531 exhibited high affinity at recombinant human EP(4) receptors expressed in cell lines (pK(B) 7.6) and native EP(4) receptors in human cerebral and meningeal artery (pK(B) 7.6-7.8) but showed no appreciable affinity at a wide range of other receptors (including other prostanoid receptors), channels, transporters and enzymes (pKi < 5). BGC20-1531 competitively antagonized PGE(2)-induced vasodilatation of human middle cerebral (pK(B) 7.8) and meningeal (pK(B) 7.6) arteries in vitro, but had no effect on responses induced by PGE(2) on coronary, pulmonary or renal arteries in vitro. BGC20-1531 (1-10 mg.kg(-1) i.v.) caused a dose-dependent antagonism of the PGE(2)-induced increase in canine carotid blood flow in vivo.

CONCLUSIONS AND IMPLICATIONS

BGC20-1531 is a potent and selective antagonist at EP(4) receptors in vitro and in vivo, with the potential to alleviate the symptoms of migraine that result from cerebral vasodilatation. BGC20-1531 is currently in clinical development for the treatment of migraine headache.

Infection with Menangle virus in flying foxes (Pteropus spp.) in Australia

OBJECTIVE

To examine flying foxes (Pteropus spp.) for evidence of infection with Menangle virus.

DESIGN

Clustered non-random sampling for serology, virus isolation and electron microscopy (EM).

PROCEDURE

Serum samples were collected from 306 Pteropus spp. in northern and eastern Australia and tested for antibodies against Menangle virus (MenV) using a virus neutralisation test (VNT). Virus isolation was attempted from tissues and faeces collected from 215 Pteropus spp. in New South Wales. Faecal samples from 68 individual Pteropus spp. and four pools of faeces were examined by transmission EM following routine negative staining and immunogold labelling.

RESULTS

Neutralising antibodies (VNT titres > or = 8) against MenV were detected in 46% of black flying foxes (P. alecto), 41% of grey-headed flying foxes (P. poliocephalus), 25% of spectacled flying foxes (P. conspicillatus) and 1% of little red flying foxes (P. scapulatus) in Australia. Positive sera included samples collected from P. poliocephalus in a colony adjacent to a piggery that had experienced reproductive disease caused by MenV. Virus-like particles were observed by EM in faeces from Pteropus spp. and reactivity was detected in pooled faeces and urine by immunogold EM using sera from sows that had been exposed to MenV. Attempts to isolate the virus from the faeces and tissues from Pteropus spp. were unsuccessful.

CONCLUSION

Serological evidence of infection with MenV was detected in Pteropus spp. in Australia. Although virus-like particles were detected in faeces, no viruses were isolated from faeces, urine or tissues of Pteropus spp.

Crucial role of c-Jun NH2-terminal kinase 1 (JNK1) in cold-restraint stress-induced gastric lesions in mice

c-Jun NH2-terminal kinase 1 /JNK1, is activated in response to a broad array of cellular stresses. We investigated the role of JNK1 in the pathophysiology of cold-restraint stress-induced gastric lesions in mice. B6/129, wild type (WT) mice, or mutant mice deficient in Jnk1 (Jnk1-/- mice) were exposed to cold-restraint stress for different time periods. Gastric lesions were identified and quantitated by morphometric analysis. JNK1 activity in mucosal homogenates was quantitated by immunoprecipitation and in-vitro kinase assays. JNK1 expression and Akt activation were assessed by Western blots with anti-JNK1 and anti-phospho Akt antibodies, respectively. Gastric mucosal homogenates from Jnk1-/- mice exhibited no significant expression of JNK1 and no detectable level of JNK1 activation. Exposure of WT mice to cold-restraint stress led to the development of significant gastric lesions and to a greater than three-fold induction in JNK1 activity, while no lesions were detected in the gastric mucosa of Jnk1-/- mice. Since cold-restraint stress-induced gastric lesions involve the activation of cholinergic pathways, we tested the effect of atropine on both the development of gastric lesions and JNK1 activation. Pretreatment of WT mice with atropine completely inhibited both cold-restraint stress-induced lesions and JNK1 activation. Cold-restraint stress induced protein kinase B/Akt to a similar level in the gastric mucosa of both WT and Jnk1-/- mice indicating the integrity of other signaling pathways. JNK1 plays a key role in the development of cold-restraint stress-induced gastric lesions in mice through the activation of cholinergic, atropine sensitive pathways.

Role of mitogen-activated protein kinase kinase 4 in cancer

Mitogen-activated protein (MAP) kinase kinase 4 (MKK4) is a component of stress activated MAP kinase signaling modules. It directly phosphorylates and activates the c-Jun N-terminal kinase (JNK) and p38 families of MAP kinases in response to environmental stress, pro-inflammatory cytokines and developmental cues. MKK4 is ubiquitously expressed and the targeted deletion of the Mkk4 gene in mice results in early embryonic lethality. Further studies in mice have indicated a role for MKK4 in liver formation, the immune system and cardiac hypertrophy. In humans, it is reported that loss of function mutations in the MKK4 gene are found in approximately 5% of tumors from a variety of tissues, suggesting it may have a tumor suppression function. Furthermore, MKK4 has been identified as a suppressor of metastasis of prostate and ovarian cancers. However, the role of MKK4 in cancer development appears complex as other studies support a pro-oncogenic role for MKK4 and JNK. Here we review the biochemical and functional properties of MKK4 and discuss the likely mechanisms by which it may regulate the steps leading to the formation of cancers.

Induction of activating transcription factor 3 by anoxia is independent of p53 and the hypoxic HIF signalling pathway

Solid tumors often have an inadequate blood supply, which results in large regions that are subjected to hypoxic or anoxic stress. Hypoxia-inducible factor-1 (HIF-1) is a transcription factor that regulates much of the transcriptional response of cells to hypoxia. Activating transcription factor 3 (ATF3) is another transcription factor that responds to a variety of stresses and is often upregulated in cancer. We investigated the regulation of ATF3 by oxygen deprivation. ATF3 induction occurred most robustly under anoxia, is common, and it is not dependent on presence of HIF-1 or p53, but is sensitive to the inhibition of c-Jun NH2-terminal kinase activation and the antioxidant N-acetylcystein. ATF3 could also be induced by desferrioxamine but not by the mitochondrial poison cyanide or the nonspecific 2-oxoglutarate dioxygenase inhibitor dimethyloxalylglycine. We also show that anoxic ATF3 mRNA is more stable than normoxic mRNA providing a mechanism for this induction. Thus, this study demonstrates that the regulation of ATF3 under anoxia is independent of 2-oxoglutarate dioxygenase, HIF-1 and p53, presumably involving multiple regulatory pathways.

An asymmetric shock wave in the 2006 outburst of the recurrent nova RS Ophiuchi

Nova outbursts take place in binary star systems comprising a white dwarf and either a low-mass Sun-like star or, as in the case of the recurrent nova RS Ophiuchi, a red giant. Although the cause of these outbursts is known to be thermonuclear explosion of matter transferred from the companion onto the surface of the white dwarf, models of the previous (1985) outburst of RS Ophiuchi failed to adequately fit the X-ray evolution and there was controversy over a single-epoch high-resolution radio image, which suggested that the remnant was bipolar rather than spherical as modelled. Here we report the detection of spatially resolved structure in RS Ophiuchi from two weeks after its 12 February 2006 outburst. We track an expanding shock wave as it sweeps through the red giant wind, producing a remnant similar to that of a type II supernova but evolving over months rather than millennia. As in supernova remnants, the radio emission is non-thermal (synchrotron emission), but asymmetries and multiple emission components clearly demonstrate that contrary to the assumptions of spherical symmetry in models of the 1985 explosion, the ejection is jet-like, collimated by the central binary whose orientation on the sky can be determined from these observations.

Procholinergic and memory enhancing properties of the selective norepinephrine uptake inhibitor atomoxetine

Atomoxetine has been approved by the FDA as the first new drug in 30 years for the treatment of attention deficit/hyperactivity disorder (ADHD). As a selective norepinephrine uptake inhibitor and a nonstimulant, atomoxetine has a different mechanism of action from the stimulant drugs used up to now for the treatment of ADHD. Since brain acetylcholine (ACh) has been associated with memory, attention and motivation, processes dysregulated in ADHD, we investigated the effects of atomoxetine on cholinergic neurotransmission. We showed here that, in rats, atomoxetine (0.3-3 mg/kg, i.p.),--increases in vivo extracellular levels of ACh in cortical but not subcortical brain regions. The marked increase of cortical ACh induced by atomoxetine was dependent upon norepinephrine alpha-1 and/or dopamine D1 receptor activation. We observed similar increases in cortical and hippocampal ACh release with methylphenidate (1 and 3 mg/kg, i.p.)--currently the most commonly prescribed medication for the treatment of ADHD--and with the norepinephrine uptake inhibitor reboxetine (3-30 mg/kg, i.p.). Since drugs that increase cholinergic neurotransmission are used in the treatment of cognitive dysfunction and dementias, we also investigated the effects of atomoxetine on memory tasks. We showed that, consistent with its cortical procholinergic and catecholamine-enhancing profile, atomoxetine (1-3 mg/kg, p.o.) significantly ameliorated performance in the object recognition test and the radial arm-maze test.

Excretion of bluetongue virus in cattle semen: a feature of laboratory-adapted virus

A series of experiments was conducted over a period of four years and involved both young (2-4 years) and old bulls (5-15 years) that were both naturally and experimentally infected with bluetongue virus (BTV). Several different virus serotypes were studied. In the Northern Territory, young bulls were exposed to natural infection with BTV over three wet seasons. During this time, bulls were infected with BTV-1, BTV-3, BTV-16 and BTV-20. In New South Wales, semen samples were examined from a large group of bulls of mixed ages that were naturally infected with BTV-1. Experimental infections in both young and old bulls (5-8 animals per group) employed both 'wild-type' and laboratory-adapted viruses from serotypes 1 and 23. A total of 41 bulls were included in the studies of natural BTV infection and 52 bulls in experimental infections. There was no evidence of BTV in any of the semen samples collected from naturally infected bulls or experimentally infected young bulls. BTV was detected intermittently in semen from a number of old bulls infected with both laboratory-adapted BTV-1 and BTV-23. These detections occurred during or immediately after the period of detectable viraemia. Virus was also detected in a few semen samples from very old bulls infected with 'wild-type' BTV-23. These samples were collected during the period of viraemia and there was usually evidence of blood in the semen. Viraemia varied in duration between 17 and 38 days. Following immunosuppression, there was no evidence of resurgence of viraemia, or excretion of virus in semen, even in animals in which virus had been previously detected in semen. When the bulls were slaughtered, virus was not detected in any tissues.

Studies on the epidemiology of bluetongue virus in China

Sentinel herds of large ruminants were established at five centres in Yunnan Province, Peoples Republic of China, between 1995 and 1997. The application of a sensitive antigen capture ELISA to facilitate virus isolation procedures led to the isolation of 108 strains of bluetongue (BLU) virus. Serotypes isolated included types 1, 2, 3, 4, 9, 11, 12, 15, 16, 21 and 23. Virus transmission occurred over a period of 1-3 months at each of the four positive sites, giving an overall BLU virus transmission period for the province of 5 months, from early June to early November. The greatest level of transmission took place in July and August. The duration of viraemia in individual animals varied from 1 to 7 weeks, with a mean calculated for each serotype between 6 and 20 days. The study represents the first detailed investigation of the epidemiology of BLU in China utilizing sentinel herds.

Signaling and cell death in lymphocytes

After activation, CD4 helper T (Th) cells differentiate into Th1 or Th2 effector cells. These two subsets produce distinct profiles of cytokines and regulate different immune responses. Here we discuss transcription factors and signaling pathways that are selectively expressed or activated in Th1 and Th2 cells to regulate cytokine gene expression, cell proliferation and apoptosis.

Signaling by the JNK group of MAP kinases. c-jun N-terminal Kinase

c-Jun N-terminal kinase (JNK) is one of the several main MAP kinase groups identified in mammals. Original studies by use of Jurkat T cells implicated JNK in T cell activation and interleukin (IL-2) expression. Recent advances using mouse genetic approaches have revealed novel functions of this pathway in primary mouse T cells. JNK is not essential for T-cell activation; instead, it is required for helper T differentiation into effector cells and their cytokine production. In this review, we summarize these advances in understanding the expression, function, and regulation of the JNK pathway in T-lymphocyte activation and differentiation.

Long-term treatment of acromegaly with pegvisomant, a growth hormone receptor antagonist

BACKGROUND

Pegvisomant is a new growth hormone receptor antagonist that improves symptoms and normalises insulin-like growth factor-1 (IGF-1) in a high proportion of patients with acromegaly treated for up to 12 weeks. We assessed the effects of pegvisomant in 160 patients with acromegaly treated for an average of 425 days.

METHODS

Treatment efficacy was assessed by measuring changes in tumour volume by magnetic resonance imaging, and serum growth hormone and IGF-1 concentrations in 152 patients who received pegvisomant by daily subcutaneous injection for up to 18 months. The safety analysis included 160 patients some of whom received weekly injections and are excluded from the efficacy analysis.

FINDINGS

Mean serum IGF-1 concentrations fell by at least 50%: 467 mg/L (SE 24), 526 mg/L (29), and 523 mg/L (40) in patients treated for 6, 12 and 18 months, respectively (p<0.001), whereas growth hormone increased by 12.5 mg/L (2.1), 12.5 mg/L (3.0), and 14.2 mg/L (5.7) (p<0.001). Of the patients treated for 12 months or more, 87 of 90 (97%) achieved a normal serum IGF-1 concentration. In patients withdrawn from pegvisomant (n=45), serum growth hormone concentrations were 8.0 mg/L (2.5) at baseline, rose to 15.2 mg/L (2.4) on drug, and fell back within 30 days of withdrawal to 8.3 mg/L (2.7). Antibodies to growth hormone were detected in 27 (16.9%) of patients, but no tachyphylaxis was seen. Serum insulin and glucose concentrations were significantly decreased (p<0.05). Two patients experienced progressive growth of their pituitary tumours, and two other patients had increased alanine and asparate aminotransferase concentrations requiring withdrawal from treatment. Mean pituitary tumour volume in 131 patients followed for a mean of 11.46 months (0.70) decreased by 0.033 cm(3) (0.057; p=0.353).

INTERPRETATION

Pegvisomant is an effective medical treatment for acromegaly.

Requirement of two NFATc4 transactivation domains for CBP potentiation

Recruitment of the coactivator CREB-binding protein (CBP) to transcription factors is important for gene expression. Various regions of CBP such as the KIX and CH3 domains have been shown to interact with numerous transcription factors. The NFAT group of transcription factors is involved in multiple biological processes. NFATc4/NFAT3 has been proposed to play an important role in heart hypertrophy, adipocyte differentiation, and learning and memory. We demonstrate here that two transactivation domains, located at the NH(2) and COOH termini of NFATc4, are critical for interacting with CBP. Each transactivation domain interacts with a distinct region of the CBP protein (the KIX and CH3 domains). Binding of CBP potentiates NFATc4-mediated transcription activity. Both transactivation domains of NFATc4 are required for CBP function. Removal of either NFATc4 transactivation domain abolishes CBP potentiation. Conversely, mutation of the KIX or CH3 domain prevents CBP-mediated potentiation of NFATc4 transcription activation. These data demonstrate that formation of a functional NFATc4.CBP transcription complex requires interactions at two distinct sites.

Beta-amyloid induces neuronal apoptosis via a mechanism that involves the c-Jun N-terminal kinase pathway and the induction of Fas ligand

Elevated levels of beta-Amyloid (Abeta) are present in the brains of individuals with either the sporadic or familial form of Alzheimer's disease (AD), and the deposition of Abeta within the senile plaques that are a hallmark of AD is thought to be a primary cause of the cognitive dysfunction that occurs in AD. Recent evidence suggests that Abeta induces neuronal apoptosis in the brain and in primary neuronal cultures, and that this Abeta-induced neuronal death may be responsible in part for the cognitive decline found in AD patients. In this study we have characterized one mechanism by which Abeta induces neuronal death. We found that in cortical neurons exposed to Abeta, activated c-Jun N-terminal kinase (JNK) is required for the phosphorylation and activation of the c-Jun transcription factor, which in turn stimulates the transcription of several key target genes, including the death inducer Fas ligand. The binding of Fas ligand to its receptor Fas then induces a cascade of events that lead to caspase activation and ultimately cell death. By analyzing the effects of mutations in each of the components of the JNK-c-Jun-Fas ligand-Fas pathway, we demonstrate that this pathway plays a critical role in mediating Abeta-induced death of cultured neurons. These findings raise the possibility that the JNK pathway may also contribute to Abeta-dependent death in AD patients.

Requirement of the JIP1 scaffold protein for stress-induced JNK activation

The c-Jun N-terminal kinase (JNK) signal transduction pathway is activated in response to the exposure of cells to environmental stress. Components of the JNK signaling pathway interact with the JIP1 scaffold protein. JIP1 is located in the neurites of primary hippocampal neurons. However, in response to stress, JIP1 accumulates in the soma together with activated JNK and phosphorylated c-Jun. Disruption of the Jip1 gene in mice by homologous recombination prevented JNK activation caused by exposure to excitotoxic stress and anoxic stress in vivo and in vitro. These data show that the JIP1 scaffold protein is a critical component of a MAP-kinase signal transduction pathway.

Discordance between the binding affinity of mitogen-activated protein kinase subfamily members for MAP kinase phosphatase-2 and their ability to activate the phosphatase catalytically

MKP-2 is a member of the mitogen-activated protein (MAP) kinase phosphatase family which has been suggested to play an important role in the feedback control of MAP kinase-mediated gene expression. Although MKP-2 preferentially inactivates extracellular signal-regulated kinase (ERK) and c-Jun NH(2)-terminal kinase (JNK) MAP kinase subfamilies, the mechanisms underlying its own regulation remain unclear. In this report, we have examined the MKP-2 interaction with and catalytic activation by distinct MAP kinase subfamilies. We found that the catalytic activity of MKP-2 was enhanced dramatically by ERK and JNK but was affected only minimally by p38. By contrast, p38 and ERK bound MKP-2 with comparably strong affinities, whereas JNK and MKP-2 interacted very weakly. Through site-directed mutagenesis, we defined the ERK/p38-binding site as a cluster of arginine residues in the NH(2)-terminal domain of MKP-2. Mutation of the basic motif abrogated its interaction with both ERK and p38 and severely compromised the catalytic activation of MKP-2 by these kinases. Unexpectedly, such mutations had little effect on JNK-triggered catalytic activation. Both in vitro and in vivo, wild type MKP-2 effectively inactivated ERK2 whereas MKP-2 mutants incapable of binding to ERK/p38 did not. Finally, in addition to its role as a docking site for ERK and p38, the MKP-2 basic motif plays a role in regulating its nuclear localization. Our studies provided a mechanistic explanation for the substrate preference of MKP-2 and suggest that catalytic activation of MKP-2 upon binding to its substrates is crucial for its function.

Positive signaling through CD72 induces mitogen-activated protein kinase activation and synergizes with B cell receptor signals to induce X-linked immunodeficiency B cell proliferation

CD72 is a 45-kDa B cell transmembrane glycoprotein that has been shown to be important for B cell activation. However, whether CD72 ligation induces B cell activation by delivering positive signals or sequestering negative signals away from B cell receptor (BCR) signals remains unclear. Here, by comparing the late signaling events associated with the mitogen-activated protein kinase pathway, we identified many similarities and some differences between CD72 and BCR signaling. Thus, CD72 and BCR activated the extracellular signal-regulated kinase (ERK) and the c-Jun N-terminal kinase (JNK) but not p38 mitogen-activated protein kinase. Both CD72- and BCR-mediated ERK and JNK activation required protein kinase C activity, which was equally important for CD72- and BCR-induced B cell proliferation. However, CD72 induced stronger JNK activation compared with BCR. Surprisingly, the JNK activation induced by both BCR and CD72 is Btk independent. Although both CD72 and BCR induced Btk-dependent ERK activation, CD72-mediated proliferation is more resistant to blocking of ERK activity than that of BCR, as shown by the proliferation response of B cells treated with PD98059 and dibutyryl cAMP, agents that inhibit ERK activity. Most importantly, CD72 signaling compensated for defective BCR signaling in X-linked immunodeficiency B cells and partially restored the proliferation response of X-linked immunodeficiency B cells to anti-IgM ligation. These results suggest that CD72 signals B cells by inducing BCR-independent positive signaling pathways.

Signaling by the JNK group of MAP kinases. c-jun N-terminal Kinase

c-Jun N-terminal kinase (JNK) is one of the several main MAP kinase groups identified in mammals. Original studies by use of Jurkat T cells implicated JNK in T cell activation and interleukin (IL-2) expression. Recent advances using mouse genetic approaches have revealed novel functions of this pathway in primary mouse T cells. JNK is not essential for T-cell activation; instead, it is required for helper T differentiation into effector cells and their cytokine production. In this review, we summarize these advances in understanding the expression, function, and regulation of the JNK pathway in T-lymphocyte activation and differentiation.

MKK7 is an essential component of the JNK signal transduction pathway activated by proinflammatory cytokines

Mitogen-activated protein kinases (MAPK) are activated by phosphorylation on Thr and Tyr by MAPK kinases. Two MAPK kinases (MKK4 and MKK7) can activate the c-Jun NH(2)-terminal kinase (JNK) group of MAPK in vitro. JNK is phosphorylated preferentially on Tyr by MKK4 and on Thr by MKK7. Targeted gene-disruption studies in mice were performed to examine the role of MKK4 and MKK7 in vivo. Simultaneous disruption of the Mkk4 and Mkk7 genes was required to block JNK activation caused by exposure of cells to environmental stress. In contrast, disruption of the Mkk7 gene alone was sufficient to prevent JNK activation caused by proinflammatory cytokines. These data demonstrate that MKK4 and MKK7 serve different functions in the JNK signal transduction pathway.

Pro-apoptotic gene expression mediated by the p38 mitogen-activated protein kinase signal transduction pathway

Neurotrophic factor deprivation causes apoptosis by a mechanism that requires macromolecular synthesis. This fact suggests that gene expression is necessary to achieve cell death. To identify mRNA that is expressed in apoptotic cells we used subtractive hybridization with cDNA prepared from neuronal pheochromocytoma cells. Monoamine oxidase (MAO) expression was increased in cells during nerve growth factor withdrawal-induced apoptosis. The increased apoptosis and induction of MAO was prevented by inhibition of the p38 mitogen-activated protein (MAP) kinase pathway. MAO may contribute to the apoptotic process because inhibition of MAO activity suppressed cell death. Together, these data indicate that MAO may be a target of pro-apoptotic signal transduction by the p38 MAP kinase pathway.

Identification of a motif in the carboxyl terminus of beta -arrestin2 responsible for activation of JNK3

Accumulating evidence indicates that the beta-arrestins act as scaffold molecules that couple G-protein-coupled receptors to mitogen-activated protein (MAP) kinase signaling pathways. Recently, we identified the c-Jun N-terminal kinase 3 (JNK3) as a beta-arrestin2-interacting protein in yeast-two hybrid and co-immunoprecipitation studies. Beta-arrestin2 acts as a scaffold to enhance signaling to JNK3 stimulated by overexpression of the MAP3 kinase ASK1 or by agonist activation of the angiotensin 1A receptor. Whereas beta-arrestin2 is a very strong activator of JNK3 signaling, beta-arrestin1 is very weak in this regard. The data also indicate that the specific step enhanced by beta-arrestin2 involves phosphorylation of JNK3 by the MAP2 kinase MKK4. We reasoned that defining the region (or domain) in beta-arrestin2 responsible for high level JNK3 activation would provide insight into the mechanism by which beta-arrestin2 enhances the activity of this signaling pathway. Using chimeric beta-arrestins, we have determined that sequences in the carboxyl-terminal region of beta-arrestin2 are important for the enhancement of JNK3 phosphorylation. More detailed analysis of the carboxyl-terminal domains of the beta-arrestins indicated that beta-arrestin2, but not beta-arrestin1, contains a sequence (RRSLHL) highly homologous to the conserved docking motif present in many MAP kinase-binding proteins. Replacement of the beta-arrestin2 RRS residues with the corresponding KP residues present in beta-arrestin1 dramatically reduced both JNK3 interaction and enhancement of JNK3 phosphorylation. Conversely, replacement of the KP residues in beta-arrestin1 with RRS significantly increased both JNK3 binding and enhancement of JNK3 phosphorylation. These results delineate a mechanism by which beta-arrestin2 functions as a scaffold protein in the JNK3 signaling pathway and implicate the conserved docking site in beta-arrestin2 as an important factor in binding JNK3 and stimulating the phosphorylation of JNK3 by MKK4.

GADD45gamma mediates the activation of the p38 and JNK MAP kinase pathways and cytokine production in effector TH1 cells

The p38 and JNK stress-activated MAPK signal transduction pathways are activated by T cell receptor (TCR) signaling and are required for IFN-gamma production by TH1 effector cells. Here, we show that the expression of GADD45gamma is induced during T cell activation and that the level of expression is higher in TH1 cells than in TH2 cells. TH1 cells from GADD45gamma(-/-) mice are severely compromised in their abilities to activate p38 and JNK in response to TCR signaling, produce much less IFN-gamma upon restimulation, and are deficient in activation-induced cell death (AICD). Additionally, GADD45gamma deficiencies caused reduced contact hypersensitivity in mice. Thus, GADD45gamma mediates activation of the p38 and JNK pathways and effector function of TH1 cells.

Molecular basis of T-cell differentiation

In summary, a multitude of regulatory systems are employed to cause the selective activation of target cytokine genes in Th1 and Th2 effector cells. These mechanisms involve both positive and negative regulation and employ at least three kinds of mechanisms. In the first, selective expression of transcription factors such as GATA3 in Th2 cells and the homeobox gene HLX in Th1 cells occurs, and appears in both cases to play a causal role. Another example of this would be c-maf, discovered by the Glimcher laboratory. A second mechanism is by the selective accumulation of protein through posttranscriptional mechanisms. Thus, junB accumulates in Th2 cells despite the fact that the junB mRNA levels are not different between Th1 and Th2 cells. Finally, the selective use of signaling pathways, in the case studied here MAP kinase pathways, leads to the selective activation of target genes. We believe that transcriptional up-regulation of rac2 leads to the coupling of both the p38 and JNK MAP kinase pathways to the T-cell receptor and/or costimulatory receptors, thereby providing a lineage-specific signal.