Schizophrenia is a chronic, complex and heterogeneous mental disorder, with pathological features of disrupted neuronal excitability and plasticity within limbic structures of the brain. These pathological features manifest behaviorally as positive symptoms (including hallucinations, delusions and thought disorder), negative symptoms (such as social withdrawal, apathy and emotional blunting) and other psychopathological symptoms (such as psychomotor retardation, lack of insight, poor attention and impulse control). Altered glutamate neurotransmission has for decades been linked to schizophrenia, but all commonly prescribed antipsychotics act on dopamine receptors. LY404039 is a selective agonist for metabotropic glutamate 2/3 (mGlu2/3) receptors and has shown antipsychotic potential in animal studies. With data from rodents, we provide new evidence that mGlu2/3 receptor agonists work by a distinct mechanism different from that of olanzapine. To clinically test this mechanism, an oral prodrug of LY404039 (LY2140023) was evaluated in schizophrenic patients with olanzapine as an active control in a randomized, three-armed, double-blind, placebo-controlled study. Treatment with LY2140023, like treatment with olanzapine, was safe and well-tolerated; treated patients showed statistically significant improvements in both positive and negative symptoms of schizophrenia compared to placebo (P < 0.001 at week 4). Notably, patients treated with LY2140023 did not differ from placebo-treated patients with respect to prolactin elevation, extrapyramidal symptoms or weight gain. These data suggest that mGlu2/3 receptor agonists have antipsychotic properties and may provide a new alternative for the treatment of schizophrenia.

No abstract

BACE1 is a key protease controlling the formation of amyloid ␤, a peptide hypothesized to play a significant role in the pathogenesis of Alzheimer's disease (AD). Therefore, the development of potent and selective inhibitors of BACE1 has been a focus of many drug discovery efforts in academiaandindustry.Herein,wereportthenonclinicalandearlyclinicaldevelopmentofLY2886721,aBACE1activesiteinhibitorthatreached phase 2 clinical trials in AD. LY2886721 has high selectivity against key off-target proteases, which efficiently translates in vitro activity into robust in vivo amyloid ␤ lowering in nonclinical animal models. Similar potent and persistent amyloid ␤ lowering was observed in plasma and lumbar CSF when single and multiple doses of LY2886721 were administered to healthy human subjects. Collectively, these data add support for BACE1 inhibition as an effective means of amyloid lowering and as an attractive target for potential disease modification therapy in AD.

Excitatory dicarboxylic amino acids previously have been ascribed several functions in the brain. Here their total concentration and proposed neurochemical markers of neurotransmitter function have been measured in brain from patients with Alzheimer's disease (AD) and controls. Specimens were obtained antemortem (biopsy) approximately 3 years after emergence of symptoms and promptly (less than 3 h) postmortem some 10 years after onset. Early in the disease a slight elevation in aspartic acid concentration of cerebral cortex was observed in the patients with AD. A reduction in glutamic acid concentration of a similar magnitude was found. It is argued that this, together with a decrease in CSF glutamine content and lack of change in the phosphate-activated brain glutaminase activity of tissue, reflects an early metabolic abnormality. Later in the disease evidence of glutamatergic neurone loss is provided by the finding that in many regions of the cerebral cortex the Na+-dependent uptake of D-[3H]aspartic acid was almost always lowest in AD subjects compared with control when assessed by a method designed to minimise artifacts and epiphenomena. Release of endogenous neurotransmitters from human brain tissue postmortem did not appear to have the characteristics of that from human tissue antemortem and rat brain.

Interaction of glycolytic enzymes with F-actin is suggested to be a mechanism for compartmentation of the glycolytic pathway. Earlier work demonstrates that muscle F-actin strongly binds glycolytic enzymes, allowing for the general conclusion that "actin binds enzymes", which may be a generalized phenomenon. By taking actin from a lower form, such as yeast, which is more deviant from muscle actin than other higher animal forms, the generality of glycolytic enzyme interactions with actin and the cytoskeleton can be tested and compared with higher eukaryotes, e.g., rabbit muscle. Cosedimentation of rabbit skeletal muscle and yeast F-actin with muscle fructose-1,6-bisphosphate aldolase (aldolase) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) followed by Scatchard analysis revealed a biphasic binding, indicating high- and low-affinity domains. Muscle aldolase and GAPDH showed low-affinity for binding yeast F-actin, presumably because of fewer acidic residues at the N-terminus of yeast actin; this difference in affinity is also seen in Brownian dynamics computer simulations. Yeast GAPDH and aldolase showed low-affinity binding to yeast actin, which suggests that actin-glycolytic enzyme interactions may also occur in yeast although with lower affinity than in higher eukaryotes. The cosedimentation results were supported by viscometry results that revealed significant cross-linking at lower concentrations of rabbit muscle enzymes than yeast enzymes. Brownian dynamics simulations of yeast and muscle aldolase and GAPDH with yeast and muscle actin compared the relative association free energy. Yeast aldolase did not specifically bind to either yeast or muscle actin. Yeast GAPDH did bind to yeast actin although with a much lower affinity than when binding muscle actin. The binding of yeast enzymes to yeast actin was much less site specific and showed much lower affinities than in the case with muscle enzymes and muscle actin.

Syntaxin 1, synaptobrevins or vesicle-associated membrane proteins, and the synaptosome-associated protein of 25 kDa (SNAP-25) are key molecules involved in the docking and fusion of synaptic vesicles with the presynaptic membrane. We report here the molecular, cell biological, and biochemical characterization of a 32-kDa protein homologous to both SNAP-25 (20% amino acid sequence identity) and the recently identified SNAP-23 (19% amino acid sequence identity). Northern blot analysis shows that the mRNA for this protein is widely expressed. Polyclonal antibodies against this protein detect a 32-kDa protein present in both cytosol and membrane fractions. The membranebound form of this protein is revealed to be primarily localized to the Golgi apparatus by indirect immunofluorescence microscopy, a finding that is further established by electron microscopy immunogold labeling showing that this protein is present in tubular-vesicular structures of the Golgi apparatus. Biochemical characterizations establish that this protein behaves like a SNAP receptor and is thus named Golgi SNARE of 32 kDa (GS32). GS32 in the Golgi extract is preferentially retained by the immobilized GST-syntaxin 6 fusion protein. The coimmunoprecipitation of syntaxin 6 but not syntaxin 5 or GS28 from the Golgi extract by antibodies against GS32 further sustains the preferential interaction of GS32 with Golgi syntaxin 6. INTRODUCTIONSoluble N-ethylmaleimide-sensitive factor (NSF) and soluble NSF attachment proteins (SNAPs) play a central role along the secretory pathway and in other trafficking events (Graham and Emr, 1991;Pryer et al., 1992;Rothman, 1994;Rothman and Wieland, 1996;Whiteheart and Kubalek, 1995;Schekman and Orci, 1996). The action of SNAPs and NSF is mediated by SNAP receptors (SNAREs) on the membrane (Rothman, 1994;Whiteheart and Kubalek, 1995). The SNARE hypothesis is proposed to account for the specificity of vesicle transport and predicts that specific interaction between vesicle-associated SNAREs with the cognate SNAREs (t-SNAREs) on the target membrane (Rothman, 1994;Whiteheart and Kubalek, 1995) is central for vesicle docking onto and fusion with the correct target membrane. Synaptobrevin or vesicle-associated membrane proteins (VAMP 1) are vesicle-associated SNAREs associated with synaptic vesicles, whereas syntaxin 1 and the synaptosomeassociated protein of 25 kDa (SNAP-25) are t-SNAREs associated with the presynaptic membrane. The specific interaction of synaptobrevin or VAMP 1 with a complex of syntaxin 1 and SNAP-25 is involved in the docking and fusion of synaptic vesicles with the presynaptic membrane (Sö llner et al., 1993;Ferro-Novick and Jahn, 1994;Rothman, 1994;Rothman and Warren, 1994;Scheller, 1995;Sü dhof, 1995;Weber et al., 1998).In addition to involvement in synaptic vesicle docking and fusion, syntaxin-like proteins have also been implicated in transport events that occur on the plasma membrane and in intracellular organelles. In yeast, Sso1p and Sso2p are involved in the docking ‡ Corresponding author. E-m...

The concentration of the inhibitory neurotransmitter, gamma-aminobutyric acid (GABA), was measured in the cerebral cortex obtained at diagnostic craniotomy from 10 patients with Alzheimer's disease of 3 yrs mean duration and 6 patients with other causes of dementia, and from 31 subjects undergoing other neurosurgical procedures (for which removal of apparently normal tissue was necessary). GABA content of 5 areas of the cerebral cortex and the cerebellar cortex was measured postmortem in the brains of 23 Alzheimer and 19 control subjects and 5 patients with other causes of dementia. Fourteen of these specimens, including 7 from patients with Alzheimer's disease of 8 yrs mean duration, were obtained within 3 h of death. These were processed in a similar manner to the neurosurgical specimens and are regarded also as fresh tissue samples. The remaining 33 specimens are regarded as conventional postmortem samples as the mean interval of death to autopsy was 21 h. GABA concentration in conventional autopsy specimens from Alzheimer subjects was not reduced as compared with controls in either cingulate or cerebellar cortex. In the inferior parietal cortex, agonal status confounded this comparison. The concentration was reduced in superior parietal, frontal and temporal cortex but there is a possibility that agonal state also confounded these comparisons. There was no deficit in GABA concentration in fresh cortical tissue from Alzheimer patients except for the temporal lobe from autopsy specimens. The content of somatostatin-like immunoreactivity was, like GABA, found to be comparable to control in some groups of Alzheimer specimens. It is argued that the deficits in autopsy samples and lack of change in surgical specimens is likely to be due to the duration of illness at the time of sampling. Losses of choline acetyltransferase activity were observed in all groups of Alzheimer specimens in all areas of brain studied. The data are consistent with other results which suggest that cholinergic under-activity is most closely related to the clinical course of Alzheimer's disease.

Background: Donanemab (LY3002813) is an IgG1 antibody directed at an N‑terminal pyroglutamate of amyloid beta epitope that is present only in brain amyloid plaques. Objectives: To assess effects of donanemab on brain amyloid plaque load after single and multiple intravenous doses, as well as pharmacokinetics, safety/tolerability, and immunogenicity. Design: Phase 1b, investigator- and patient-blind, randomized, placebo-controlled study. Setting: Patients recruited at clinical research sites in the United States and Japan. Participants: 61 amyloid plaque-positive patients with mild cognitive impairment due to Alzheimer’s disease and mild-to-moderate Alzheimer’s disease dementia. Intervention: Six cohorts were dosed with donanemab: single dose 10-, 20- or 40- mg/kg (N = 18), multiple doses of 10-mg/kg every 2 weeks for 24 weeks (N = 10), and 10- or 20-mg/kg every 4 weeks for 72 weeks (N=18) or placebo (N = 15). Measurements: Brain amyloid plaque load, using florbetapir positron emission tomography, was assessed up to 72 weeks. Safety was evaluated by occurrence of adverse events, magnetic resonance imaging, electrocardiogram, vital signs, laboratory testing, neurological monitoring, and immunogenicity. Results: Treatment with donanemab resulted in rapid reduction of amyloid, even after a single dose. By 24 weeks, amyloid positron emission tomography mean changes from baseline for single donanemab doses in Centiloids were: -16.5 (standard error 11.22) 10-mg/kg intravenous; 40.0 (standard error 11.23) 20 mg/kg intravenous; and -49.6 (standard error 15.10) 40-mg/kg intravenous. Mean reduction of amyloid plaque in multiple dose cohorts by 24 weeks in Centiloids were: 55.8 (standard error 9.51) 10-mg/kg every 2 weeks; -50.2 (standard error 10.54) 10-mg/kg every 4 weeks; and -58.4 (standard error 9.66) 20-mg/kg every 4 weeks. Amyloid on average remained below baseline levels up to 72 weeks after a single dose of donanemab. Repeated dosing resulted in continued florbetapir positron emission tomography reductions over time compared to single dosing with 6 out of 28 patients attaining complete amyloid clearance within 24 weeks. Within these, 5 out of 10 patients in the 20 mg/kg every 4 weeks cohort attained complete amyloid clearance within 36 weeks. When dosing with donanemab was stopped after 24 weeks of repeat dosing in the 10 mg every 2 weeks cohort, florbetapir positron emission tomography reductions were sustained up to 72 weeks. For the single dose cohorts on day 1, dose proportional increases in donanemab pharmacokinetics were observed from 10 to 40 mg/kg. Dose proportional increases in pharmacokinetics were also observed at steady state with the multiple dose cohorts. Donanemab clearance was comparable across the dose levels. Mean donanemab elimination-half-life following 20 mg/kg single dose was 9.3 days with range of 5.6 to 16.2 days. Greater than 90% of patients had positive treatment-emergent antidrug antibodies with donanemab. However, overall, the treatment-emergent antidrug antibodies did not have a significant impact on pharmacokinetics. Donanemab was generally well tolerated. Amongst the 46 participants treated with donanemab, the following amyloid-related imaging abnormalities, common to the drug class, were observed: 12 vasogenic cerebral edema events (12 [19.7%] patients), 10 cerebral microhemorrhage events (6 [13.0%] patients), and 2 superficial siderosis events (2 [4.3%] patients). Conclusions: Single and multiple doses of donanemab demonstrated a rapid, robust, and sustained reduction up to 72 weeks in brain amyloid plaque despite treatment-emergent antidrug antibodies detected in most patients. Amyloid-related imaging abnormalities were the most common treatment-emergent event.