Macrophage immunomodulation through new polymers that recapitulate functional effects of itaconate as a power house of innate immunity.

Itaconate (ITA) is an emerging powerhouse of innate immunity with therapeutic potential that is limited in its ability to be administered in a soluble form. We developed a library of polyester materials that incorporate ITA into polymer backbones resulting in materials with inherent immunoregulatory behavior. Harnessing hydrolytic degradation release from polyester backbones, ITA polymers resulted in the mechanism specific immunoregulatory properties on macrophage polarization in vitro. In a functional assay, the polymer-released ITA inhibited bacterial growth on acetate. Translation to an in vivo model of biomaterial associated inflammation, intraperitoneal injection of ITA polymers demonstrated a rapid resolution of inflammation in comparison to a control polymer silicone, demonstrating the value of sustained biomimetic presentation of ITA.

What causes aberrant salience in schizophrenia? A role for impaired short-term habituation and the GRIA1 (GluA1) AMPA receptor subunit.

The GRIA1 locus, encoding the GluA1 (also known as GluRA or GluR1) AMPA glutamate receptor subunit, shows genome-wide association to schizophrenia. As well as extending the evidence that glutamatergic abnormalities have a key role in the disorder, this finding draws attention to the behavioural phenotype of Gria1 knockout mice. These mice show deficits in short-term habituation. Importantly, under some conditions the attention being paid to a recently presented neutral stimulus can actually increase rather than decrease (sensitization). We propose that this mouse phenotype represents a cause of aberrant salience and, in turn, that aberrant salience (and the resulting positive symptoms) in schizophrenia may arise, at least in part, from a glutamatergic genetic predisposition and a deficit in short-term habituation. This proposal links an established risk gene with a psychological process central to psychosis and is supported by findings of comparable deficits in short-term habituation in mice lacking the NMDAR receptor subunit Grin2a (which also shows association to schizophrenia). As aberrant salience is primarily a dopaminergic phenomenon, the model supports the view that the dopaminergic abnormalities can be downstream of a glutamatergic aetiology. Finally, we suggest that, as illustrated here, the real value of genetically modified mice is not as 'models of schizophrenia' but as experimental tools that can link genomic discoveries with psychological processes and help elucidate the underlying neural mechanisms.

Factors associated with concentrations of select cytokine and acute phase proteins in dairy cows with naturally occurring clinical mastitis.

The objective of the current observational study was to determine the potential associations between cow factors, clinical mastitis (CM) etiology, and concentrations of select acute phase proteins and cytokines in milk from affected quarters of cows with CM. Cows with CM (n=197) were grouped based on systemic disease severity, milk culture result, parity, days in milk (DIM), previous CM occurrence, and season of the year when CM occurred. Concentrations of lipopolysaccharide-binding protein (LBP), haptoglobin (Hp), BSA, IFN-gamma, tumor necrosis factor-alpha (TNF-alpha), IL-1beta, IL-8, IL-10, IL-12, transforming growth factor (TGF)-alpha, and TGF-beta and activity of lactate dehydrogenase (LDH) were evaluated. Differences in the least squares means log(10) transformed concentrations of these proteins were compared using multiple linear regression mixed models. The milk concentrations of LBP, Hp, IL-1beta, IL-10, and IL-12, and activity of LDH in milk were higher in cows with moderate to severe versus mild systemic disease. The concentrations of Hp, BSA, IL-1beta, and IL-10 in milk were higher in cows with a gram-negative versus gram-positive milk culture result. Season of the year when CM occurred was associated with the concentration of all proteins evaluated except for IL-1beta and IL-12. Concentrations were higher in the winter versus summer except for Hp and TGF-beta, for which the opposite was true. Concentrations of LBP, IL-10, and IL-12, and LDH activity in milk were associated with DIM group. Except for LBP, these proteins were lower in cows with CM during the first 60 DIM versus those in mid or later lactation. Interferon-gamma, TNF-alpha, and IL-8 were undetectable in 67, 31, and 20% of samples, respectively. Detection of IFN-gamma and IL-8 was associated with season, and detection of TNF-alpha and IL-8 was associated with systemic disease severity. The current study provides the most comprehensive report of milk concentrations of innate immune response proteins in cows with naturally occurring CM and identifies factors that potentially influence those concentrations. Further investigation into the seasonal variation of cytokine production and its potential effect on the outcome of CM is warranted. Furthermore, the results of this study provide useful data for planning future studies examining the role of the innate immune response in CM.

Proteomic analysis of the temporal expression of bovine milk proteins during coliform mastitis and label-free relative quantification.

The discovery of biomarkers in milk indicative of local inflammation or disease in the bovine mammary gland has been hindered by the extreme biological complexity of milk, the dynamic range of proteins in the matrix that renders the identification of low-abundance proteins difficult, and the challenges associated with quantifying changes during disease in the abundance of proteins for which no antibody exists. The objectives of the current study were to characterize the temporal expression of milk proteins following Escherichia coli challenge and to evaluate change in relative abundance of identified proteins using a liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) label-free semiquantitative approach. Liquid chromatography-MS/MS conducted on whey from milk samples collected just before infusion with E. coli and at 12, 18, 24, 36, 48, and 60h following infection resulted in the identification of the high- to medium-abundance proteins alpha(S1)-, alpha(S2)- beta-, and kappa-caseins and the whey proteins serum albumin, beta-lactoglobulin, and alpha-lactalbumin. Additionally, a select number of lower abundance markers of inflammation were also identified, including lactoferrin, transferrin, apolipoprotein AI, fibrinogen, glycosylation-dependent cell adhesion molecule-1, peptidoglycan recognition receptor protein, and cyclic dodecapeptide-1. Normalized peptide counts for each protein identified were used to evaluate temporal changes in milk proteins following infection. For comparison with relative protein abundance determined using proteomic-based methods, changes in serum albumin, lactoferrin, and transferrin in milk during disease were also measured using ELISA. Label-free, proteomic-based quantification revealed relative changes in milk proteins that corresponded to expression profiles generated by ELISA. The results indicate that label-free LC-MS/MS methods are a viable means of tracking changes in relative protein abundance in milk during disease. Despite the identification of primarily abundant milk proteins, the results indicate that, with further refinement, LC-MS/MS could be used to evaluate temporal changes in proteins related to host response for which no antibody or ELISA currently exists.

Impulsive choice in hippocampal but not orbitofrontal cortex-lesioned rats on a nonspatial decision-making maze task.

Orbitofrontal cortical (OFC) and hippocampal (HPC) lesions in primates and rodents have been associated with impulsive behaviour. We showed previously that OFC- or HPC-lesioned rats chose the immediate low-reward (LR) option in preference to the delayed high-reward (HR) option, where LR and HR were associated with different spatial responses in a uniform grey T-maze. We now report that on a novel nonspatial T-maze task in which the HR and LR options are associated with patterned goal arms (black-and-white stripes vs. gray), OFC-lesioned rats did not show impulsive behaviour, choosing the delayed HR option, and were indistinguishable from controls. In contrast, HPC-lesioned rats exhibited impulsive choice in the nonspatial decision-making task, although they chose the HR option on the majority of trials when there was a 10-s delay associated with both goal arms. The previously reported impairment in OFC-lesioned rats on the spatial version of the intertemporal choice task is unlikely to reflect a general problem with spatial learning, because OFC lesions were without effect on acquisition of the standard reference memory water-maze task and spatial working memory performance (nonmatching-to-place) on the T-maze. The differential effect of OFC lesions on the two versions of the intertemporal choice task may be explained instead in terms of the putative role of OFC in using associative information to represent expected outcomes and generate predictions. The impulsivity in HPC-lesioned rats may reflect impaired temporal information processing, and emphasizes a role for the hippocampus beyond the spatial domain.

Enhanced host immune recognition of mastitis causing Escherchia coli in CD-14 transgenic mice.

Escherchia coli causes mastitis, an economically significant disease in dairy animals. E. coli endotoxin (lipopolysaccharide, LPS) when bound by host membrane proteins such as CD-14, causes release of proinflammatory cytokines recruiting neutrophils as an early, innate immune response. Excessive proinflammatory cytokines causes tissue damage, compromising mammary function. If present, soluble CD-14 (sCD-14) might out compete membrane bound CD-14, lessening the severity of the inflammatory response. To test this hypothesis transgenic mice, expressing sCD-14 in their milk (31 to 316 microg/ml), were evaluated. A cell culture study demonstrated, in the presence of LPS, milk from transgenic mice increased secretion of cytokine IL-8 compared to milk from nontransgenic littermates (18 +/- 3 vs. 35 +/- 2 ng/mL, p < 0.001). To assess protection afforded by the transgene, glands were infused with E. coli. Recovery of bacteria showed no clear relationship between sCD14 concentration and the number of organisms recovered; however, there was a strong relationship between sCD14 concentration and edema (r(2) = 0.999, p < 0.001), as measured by weight of fluid in harvested glands. Highest expressing lines had the least edema, suggesting the presence of sCD14 had an effect on reducing the inflammatory response to E. coli, thus, possibly protecting against gland tissue damage.

Determination of milk and blood concentrations of lipopolysaccharide-binding protein in cows with naturally acquired subclinical and clinical mastitis.

Blood and milk concentrations of the acute phase protein lipopolysaccharide-binding protein (LBP) were evaluated in cows with naturally occurring mastitis. Blood and milk samples were collected from 101 clinically healthy dairy cows and 17 dairy cows diagnosed with clinical mastitis, and the LBP concentrations of the samples were measured by an ELISA. Concentrations of LBP were greater in the blood and milk of cows with clinical mastitis than in those with healthy quarters. Concentrations of LBP also differed between uninfected and subclinically infected quarters with low somatic cell count. Blood concentrations of LBP in cows with subclinical intramammary infections could not be differentiated from those of cows with all healthy quarters. Together, these data demonstrate that increased blood and milk concentrations of LBP can be detected in dairy cows with naturally acquired intramammary infections that cause clinical mastitis.

Restoration of spatial working memory by genetic rescue of GluR-A-deficient mice.

Gene-targeted mice lacking the AMPA receptor subunit GluR-A (also called GluR1 encoded by the gene Gria1,) have deficits in hippocampal CA3-CA1 long-term potentiation (LTP) and have profoundly impaired hippocampus-dependent spatial working memory (SWM) tasks, although their spatial reference memory remains normal. Here we show that forebrain-localized expression of GFP-tagged GluR-A subunits in GluR-A-deficient mice rescues SWM, paralleling its rescue of CA3-CA1 LTP. This provides powerful new evidence linking hippocampal GluR-A-dependent synaptic plasticity to rapid, flexible memory processing.

The role of the GluR-A (GluR1) AMPA receptor subunit in learning and memory.

It is widely believed that synaptic plasticity may provide the neural mechanism that underlies certain kinds of learning and memory in the mammalian brain. The expression of long-term potentiation (LTP) in the hippocampus, an experimental model of synaptic plasticity, requires the GluR-A subunit of the AMPA subtype of glutamate receptor. Genetically modified mice lacking the GluR-A subunit show normal acquisition of the standard, fixed-location, hidden-platform watermaze task, a spatial reference memory task that requires the hippocampus. In contrast, these mice are dramatically impaired on hippocampus-dependent, spatial working memory tasks, in which the spatial response of the animal is dependent on information in short-term memory. Taken together, these results argue for two distinct and independent spatial information processing mechanisms: (i) a GluR-A-independent associative learning mechanism through which a particular spatial response is gradually or incrementally strengthened, and which presumably underlies the acquisition of the classic watermaze paradigm and (ii) a GluR-A-dependent, non-associative, short-term memory trace which determines performance on spatial working memory tasks. These results are discussed in terms of Wagner's SOP model (1981).

A role for dorsal and ventral hippocampus in inter-temporal choice cost-benefit decision making.

Previous studies suggest a preferential role for dorsal hippocampus (dHPC) in spatial memory tasks, whereas ventral hippocampus (vHPC) has been implicated in aspects of fear and/or anxiety. In this study, we tested the hypothesis that vHPC may be a critical subregion for performance on a delay-based, cost-benefit decision making task. Rats chose between the two goal arms of a T maze, one containing an immediately available small reward, the other containing a larger reward that was only accessible after a delay. dHPC, vHPC, and complete hippocampal (cHPC) lesions all reduced choice of the delayed high reward (HR) in favor of the immediately available low reward (LR). The deficits were not due to a complete inability to remember which reward size was associated with which arm of the maze. When an equivalent 10-s delay was introduced in both goal arms, all rats chose the HR arm on nearly all trials. The deficit was, however, reinstated when the inequality was reintroduced. Our results suggest an important role for both dHPC and vHPC in the extended neural circuitry that underlies intertemporal choice.

Mice overexpressing the 5-hydroxytryptamine transporter show no alterations in feeding behaviour and increased non-feeding responses to fenfluramine.

RATIONALE: The 5-HT transporter (5-HTT) is implicated in the regulation of appetite. Expression of the 5-HTT varies in the human population, and this variation may determine both individual differences in feeding and abnormal feeding behaviours such as eating disorders. OBJECTIVES: The effects of 5-HTT expression on feeding and satiety were examined in a transgenic mouse model of 5-HTT overexpression. MATERIALS AND METHODS: We measured free-feeding food intake and observed the behavioural satiety sequence (BSS) after food deprivation in mice at baseline and after administration of the anorectic drug fenfluramine. RESULTS: 5-HTT overexpressing mice were both lighter and shorter than their wildtype littermates. Despite this size difference, food intake by transgenic and wildtype mice did not differ. There was no effect of genotype on the BSS or on food intake during the test at baseline. Increasing doses of fenfluramine reduced food intake in a similar manner in both transgenic and wildtype mice. After 0.3 and 1 mg/kg fenfluramine, the temporal pattern of the BSS was the same for both groups, whereas 3 and 10 mg/kg fenfluramine disrupted the BSS. In transgenic mice, this disruption was evident at the 3 mg/kg dose, while in wildtypes, it emerged only at the 10-mg/kg dose. CONCLUSION: These data suggest that overexpression of the 5-HTT does not lead to alterations in feeding or satiety in food-deprived mice but does increase the occurrence of other non-feeding behaviours in response to the 5-HT releasing agent fenfluramine.

Proteomic analysis of differentially expressed proteins in bovine milk during experimentally induced Escherichia coli mastitis.

The objectives of the current study were to profile changes in protein composition using 2-dimensional gel electrophoresis on whey samples from a group of 8 cows before and 18 h after infection with Escherichia coli and to identify differentially expressed milk proteins by peptide sequencing using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry post source decay. Only proteins present in whey fractions of all 8 cows were sequenced to avoid reporting a protein response unique to only a subset of infected cows. Despite the overwhelming presence of casein and beta-lactoglobulin, the low abundance proteins transthyretin, lactadherin, beta-2-microglobulin precursor, alpha-1-acid glycoprotein, and complement C3 precursor could be identified in whey samples from healthy cows. Whey samples at 18 h postinfection were characterized by an abundance of serum albumin, in spots of varying mass and isoelectric point, as well as increased transthyretin and complement C3 precursor levels. Also detected at 18 h postinoculation were the antimicrobial peptides cathelicidin, indolicidin, and bactenecin 5 and 7, and the proteins beta-fibrinogen, alpha-2-HS-glycoprotein, S100-A12, and alpha-1-antiproteinase. Most notable was the detection of the acute phase protein alpha-1-acid glycoprotein in mastitic whey samples, a result not previously reported. In contrast to methods used in previous proteomic analyses of bovine milk, the methods used in the current study enabled the rapid identification of milk proteins with minimal sample preparation. Use of a larger sample size than previous analyses also allowed for more robust protein identification. Results indicate that examination of the protein profile of whey samples from cows after inoculation with E. coli could provide a rapid survey of milk protein modulation during coliform mastitis and aid in the identification of biomarkers of this disease.

Comparison of Holstein and Jersey innate immune responses to Escherichia coli intramammary infection.

Mastitis is one of the most prevalent diseases in cattle and remains among the most costly diseases to the dairy industry. Various surveys have indicated a greater prevalence of and risk for mastitis in Holstein cows than in Jersey cows. The innate immune system comprises the immediate host defense mechanisms that respond to infection, and differences in the magnitude and rapidity of this response are known to influence susceptibility to and clearance of infectious pathogens. The reported differences in the prevalence of mastitis between Holstein and Jersey cows may suggest the occurrence of breed-dependent differences in the innate immune response to intramammary infection. The objective of the current study was to compare the acute phase and cytokine responses of Holstein and Jersey cows following intramammary infection by the bacterial pathogen Escherichia coli, a leading cause of clinical mastitis. All cows in the study were in similar stages of lactation, of the same parity, subjected to the same housing and management conditions, and experimentally infected on the same day with the same inoculum preparation. Before and after infection, the following innate immune parameters were monitored: bacterial clearance; febrile response; induction of the acute phase proteins serum amyloid A and lipopolysaccharide-binding protein; alterations in total and differential white blood cell counts; changes in milk somatic cell counts and mammary vascular permeability; and induction of the cytokines IFN-gamma, IL-1beta, IL-8, IL-12, and tumor necrosis factor-alpha. Overall innate immune responses were similar between the 2 breeds; however, temporal differences in the onset, cessation, and duration of several responses were detected. Despite these differences, intramammary clearance of E. coli was comparable between the breeds. Together, these data demonstrate a highly conserved innate immune response of Holstein and Jersey cows to E. coli intramammary infection.

Spatial memory dissociations in mice lacking GluR1.

Gene-targeted mice lacking the AMPA receptor subunit GluR1 (GluR-A) have deficits in hippocampal CA3-CA1 long-term potentiation. We now report that they showed normal spatial reference learning and memory, both on the hidden platform watermaze task and on an appetitively motivated Y-maze task. In contrast, they showed a specific spatial working memory impairment during tests of non-matching to place on both the Y-maze and an elevated T-maze. In addition, successful watermaze and Y-maze reference memory performance depended on hippocampal function in both wild-type and mutant mice; bilateral hippocampal lesions profoundly impaired performance on both tasks, to a similar extent in both groups. These results suggest that different forms of hippocampus-dependent spatial memory involve different aspects of neural processing within the hippocampus.

Supersmart mice: surprising or surprised? Theoretical comment on Singer, Boison, Möhler, Feldon, and Yee (2007).

The glycine transporter (GlyT1) regulates levels of the neurotransmitter glycine, a coagonist of the N-methyl-D-aspartate receptor (NMDAR), and as such may represent a novel site for developing cognition-enhancing drugs. Genetically modified mice with reduced levels of GlyT1 have been generated to test this hypothesis. P. Singer, D. Boison, H. Möhler, J. Feldon, and B. K. Yee now show, through a spontaneous exploration task, that mice in which GlyT1 has been deleted, specifically in neurons in the forebrain, demonstrate enhanced object recognition memory. Whereas both control and mutant mice show a preference for a novel object over a familiar object 2 min after the initial presentation of 1 of the objects, only the mutant mice show a preference for the novel object when tested after a 2-hr delay. The longer-lasting habituation displayed by the GlyT1 mice is consistent with a role for glycine/NMDAR-dependent synaptic plasticity in supporting a nonassociative, short-term memory trace of a recently experienced stimulus. This short-term habituation process may be independent of associative learning mechanisms and may be best described by A. R. Wagner's (1981) sometimes opponent process model.

Deletion of glutamate receptor-A (GluR-A) AMPA receptor subunits impairs one-trial spatial memory.

Genetically modified mice lacking the glutamate receptor A (GluR-A) subunit of the AMPA receptor (GluR-A-/- mice) display normal spatial reference memory but impaired spatial working memory (SWM). This study tested whether the SWM impairment in these mice could be explained by a greater sensitivity to within-session proactive interference. The SWM performance of GluR-A-/- and wild-type mice was assessed during nonmatching-to-place testing under conditions in which potential proactive interference from previous trials was reduced or eliminated. SWM was impaired in GluR-A-/- mice, both during testing with pseudotrial-unique arm presentations on the radial maze and when conducting each trial on a different 3-arm maze, each in a novel testing room. Experimentally naive GluR-A-/- mice also exhibited chance performance during a single trial of spontaneous alternation. This 1-trial spatial memory deficit was present irrespective of the delay between the sample information and the response choice (0 or 45 min) and the length of the sample phase (0.5 or 5 min). These results imply that the SWM deficit in GluR-A-/- mice is not due to increased susceptibility to proactive interference.

Innate immune response to intramammary Mycoplasma bovis infection.

The objective of the current study was to characterize the systemic and local innate immune response of dairy cows to IMI with Mycoplasma bovis, a pathogen of growing concern to the dairy industry. Ten Holstein cows were each infused in 1 quarter with M. bovis and studied for a 10-d period. Acute phase protein synthesis, which reflects 1 parameter of the systemic response to infection, was induced within 108 h of infection, as evidenced by increased circulating concentrations of lipopolysaccharide binding protein and serum amyloid A. Transient neutropenia was observed from 84 to 168 h postinfection, whereas a constant state of lymphopenia and thrombocytopenia was observed from 84 h until the end of the study. Milk somatic cell counts initially increased within 66 h of M. bovis infusion and remained elevated, relative to control (time 0) concentrations, for the remainder of study. Increased milk concentrations of BSA, which reflect increased permeability of the mammary epithelial-endothelial barrier, were evident within 78 h of infection and were sustained from 90 h until the end of the study. Milk concentrations of several cytokines, including IFN-gamma, IL-1beta, IL-10, IL-12, tumor growth factor-alpha, and tumor necrosis factor-alpha, were elevated in response to infection over a period of several days, whereas increases in milk IL-8 were of a more limited duration. Complement activation, reflected by increased milk concentrations of complement factor 5a, was also observed over several days. Despite the indication by these observed changes that the cows mounted a prolonged inflammatory response to M. bovis intramammary infection, all quarters remained infected throughout the study with persistently high concentrations of this bacterium. Thus, a sustained inflammatory response is not sufficient to eradicate M. bovis from the mammary gland and may reflect the ongoing struggle of the host to clear this persistent pathogen.

Cumulative physiological events influence the inflammatory response of the bovine udder to Escherichia coli infections during the transition period.

A high proportion of intramammary coliform infections present at parturition develop disease characterized by severe inflammatory signs and sepsis during the first 60 to 70 d of lactation. In the lactating bovine mammary gland, the innate immune system plays a critical role in determining the outcome of these infections. Since the beginning of the 1990s, research has increased significantly on bovine mammary innate defense mechanisms in connection with the pathogenesis of coliform mastitis. Neutrophils are key effector cells of the innate immune response to intramammary infection, and their function is influenced by many physiological events that occur during the transition period. Opportunistic infections occur when the integrity of the host immune system is compromised by physical and physiological conditions that make the host more susceptible. The innate immune system of many periparturient cows is immunocompromised. It is unlikely that periparturient immunosuppression is the result of a single physiological factor; more likely, several entities act in concert, with profound effects on the function of many organ systems of the periparturient dairy cow. Their defense system is unable to modulate the complex network of innate immune responses, leading to incomplete resolution of the pathogen and the inflammatory reaction. During the last 30 yr, most efforts have been focused on neutrophil diapedesis, phagocytosis, and bacterial killing. How these functions modulate the clinical outcome of coliform mastitis, and how they can be influenced by hormones and metabolism has been the subject of intensive research and is the focus of this review. The afferent (sensing) arm of innate immunity, which enables host recognition of a diverse array of pathogens, is the subject of intense research interest and may contribute to the variable inflammatory response to intramammary infections during different stages of lactation. The development of novel interventions that modulate the inflammatory response or contribute to the elimination of the pathogen or both may offer therapeutic promise in the treatment of mastitis in periparturient cows.

Sequencing, chromosomal mapping, and functional characterization of bovine FLICE-like inhibitory protein (FLIP).

FLICE-like inhibitory protein (FLIP) has been shown in both humans and mice to inhibit apoptosis and NF-kappaB activation induced by pro-inflammatory mediators. The activation of NF-kappaB and the induction of apoptosis are critical events in the pathogenesis of a variety of disease states in cattle, including mastitis. Since FLIP is known to moderate these events in other species, we mapped the bovine FLIP gene, sequenced bovine FLIP cDNA, and characterized its expression in cultured primary bovine endothelial cells. Sequencing of bovine FLIP revealed approximately 83, 74, and 68% amino acid sequence identity to its porcine, human, and murine orthologs, respectively. Bovine FLIP was mapped to chromosome 2 by radiation hybrid mapping. Interestingly the region to which bovine FLIP maps contains a putative quantitative trait locus for functional herd life which is an indicator of a cow's ability to survive involuntary culling due primarily to mastitis and infertility. In addition to sequencing and mapping, the function of bovine FLIP was studied. Over-expression of bovine FLIP protected against bacterial lipopolysaccharide (LPS)- and TNF-alpha-induced apoptosis in bovine endothelial cells consistent with previous studies of human FLIP. In addition, elevated expression of bovine FLIP blocked LPS- and TNF-alpha-induced upregulation of NF-kappaB-dependent gene products as assayed by E-selectin expression. Only the full-length bovine FLIP protein could inhibit NF-kappaB activation induced by LPS, whereas the death effector domain region alone was able to inhibit TNF-alpha-induced NF-kappaB activation. Together, these data demonstrate the conservation of FLIP's ability to inhibit apoptosis and to downregulate NF-kappaB activation across species.

The drugs don't work-or do they? Pharmacological and transgenic studies of the contribution of NMDA and GluR-A-containing AMPA receptors to hippocampal-dependent memory.

OBJECTIVE: The aim of this article is to provide a review of studies using N-methyl-D-aspartate (NMDA) receptor antagonists to assess the hippocampal long-term potentiation (LTP)/learning hypothesis. DISCUSSION: In particular, we will re-examine the validity of both (1) the original hippocampal LTP/spatial learning hypothesis of Morris and (2) the sensorimotor account put forward by Cain, among others, both from the point of view of the pharmacological studies on which they were based and with regard to recent studies with genetically modified mice. More specifically, we will review the pharmacological studies in the light of recent work on the glutamate receptor A (GluR-A or GluR1) L-alpha-amino-3-hydroxy-5-methyl-4-isoxazelopropionate (AMPA) receptor sub-unit knockout mouse. We will argue that neither the original hippocampal LTP/spatial learning hypothesis nor a sensorimotor account can adequately explain all of the available data. We argue instead that hippocampal synaptic plasticity, which requires NMDA receptors for its induction and GluR-A-containing AMPA receptors for its continued expression, contributes to a process whereby appropriate behavioural responses are selected rapidly on the basis of conditional information provided by the context. These contextual cues could include not only the spatial context (i.e. the 'where') and the temporal context (the 'when'), but also other aspects of context, such as internal state cues (hunger and fear state), and can be used to rapidly and flexibly alter valences of specific response options. RECOMMENDATIONS: We also suggest that there is a separate, distinct, NMDA/GluR-A-independent mechanism through which the context can gradually (incrementally or decrementally) alter the valence of a particular response option.