Identification of Full-Length Wild-Type and Mutant Huntingtin Interacting Proteins by Crosslinking Immunoprecipitation in Mice Brain Cortex

Background:

Huntington’s disease is a neurodegenerative disorder caused by a CAG expansion in the huntingtin gene, resulting in a polyglutamine expansion in the ubiquitously expressed mutant huntingtin protein.

Objective:

Here we set out to identify proteins interacting with the full-length wild-type and mutant huntingtin protein in the mice cortex brain region to understand affected biological processes in Huntington’s disease pathology.

Methods:

Full-length huntingtin with 20 and 140 polyQ repeats were formaldehyde-crosslinked and isolated via their N-terminal Flag-tag from 2-month-old mice brain cortex. Interacting proteins were identified and quantified by label-free liquid chromatography-mass spectrometry (LC-MS/MS).

Results:

We identified 30 interactors specific for wild-type huntingtin, 14 interactors specific for mutant huntingtin and 14 shared interactors that interacted with both wild-type and mutant huntingtin, including known interactors such as F8a1/Hap40. Syt1, Ykt6, and Snap47, involved in vesicle transport and exocytosis, were among the proteins that interacted specifically with wild-type huntingtin. Various other proteins involved in energy metabolism and mitochondria were also found to associate predominantly with wild-type huntingtin, whereas mutant huntingtin interacted with proteins involved in translation including Mapk3, Eif3h and Eef1a2.

Conclusion:

Here we identified both shared and specific interactors of wild-type and mutant huntingtin, which are involved in different biological processes including exocytosis, vesicle transport, translation and metabolism. These findings contribute to the understanding of the roles that wild-type and mutant huntingtin play in a variety of cellular processes both in healthy conditions and Huntington’s disease pathology.

Design, characterization and in vivo functioning of a light-dependent histidine protein kinase in the yeast Saccharomyces cerevisiae

Helical alignment of the α-helical linker of the LOV (light-oxygen-voltage) domain of YtvA from Bacillus subtilis with the α-helical linker of the histidine-protein kinase domain of the Sln1 kinase of the phospho-relay system for osmoregulation of Saccharomyces cerevisiae has been used to construct a light-modulatable histidine protein kinase. In vitro, illumination with blue light inhibits both the ATP-dependent phosphorylation of this hybrid kinase, as well as the phosphoryl transfer to Ypd1, the phosphoryl transfer domain of the Sln1 system. The helical alignment was carried out with conservation of the complete Jα helix of YtvA, as well as of the phosphorylatable histidine residue of the Sln1 kinase, with conservation of the hepta-helical motive of coiled-coil structures, recognizable in the helices of the two separate, constituent, proteins. Introduction of the gene encoding this hybrid histidine protein kinase into cells of S. cerevisiae in which the endogenous Sln1 kinase had been deleted, allowed us to modulate gene expression in the yeast cells with (blue) light. This was first demonstrated via the light-induced alteration of the expression level of the mannosyl-transferase OCH1, via a translational-fusion approach. As expected, illumination decreased the expression level of OCH1; the steady state decrease in saturating levels of blue light was about 40%. To visualize the in vivo functionality of this light-dependent regulation system, we fused the green fluorescent protein (GFP) to another regulatory protein, HOG1, which is also responsive to the Sln1 kinase. HOG1 is phosphorylated by the MAP-kinase-kinase Pbs2, which in turn is under control of the Sln1 kinase, via the phosphoryl transfer domain Ypd1. Fluorescence microscopy was used to show that illumination of cells that contained the combination of the hybrid kinase and the HOG1::GFP fusion protein, led to a persistent increase in the level of nuclear accumulation of HOG1, in contrast to salt stress, which-as expected-showed the well-characterized transient response. The system described in this study will be valuable in future studies on the role of cytoplasmic diffusion in signal transduction in eukaryotic cells.

Effect of vanadium chloroperoxidase on Enterococcus faecalis biofilms

INTRODUCTION

The aim of this study was to explore the antimicrobial effect of vanadium chloroperoxidase (VCPO) reaction products on Enterococcus faecalis biofilms of 4 different strains.

METHODS

Twenty-four-hour biofilms of E. faecalis strains V583, ER5/1, E2, and OS-16 were incubated in mixtures with VCPO, halide (either bromide or chloride), and hydrogen peroxide. The antibacterial efficacy was assessed by colony-forming unit counts.

RESULTS

The VCPO reaction products had a similar efficacy in reducing the viability of the 4 strains of E. faecalis (94%; range, 87%-100%). Bromide as the halogen of choice was more effective on E. faecalis strains E2 and OS-16, as compared with chloride (Mann-Whitney U test; P < .05). Despite different quantities of produced biofilms by the 4 strains, VCPO treatment was similarly effective toward all strains (Kruskal-Wallis test; P < .05).

CONCLUSIONS

VCPO treatment results in an antimicrobial effect toward in vitro E. faecalis biofilms and might provide an addition to current endodontic treatment, possibly as an antimicrobial dressing.

A national survey of endoscopic mucosal resection for superficial gastrointestinal neoplasia

BACKGROUND AND STUDY AIM

Studies on endoscopic mucosal resection (EMR) are mostly based on data from centers with high expertise. We report the average EMR results in a national survey of consecutive patients in France.

METHODS

A 1-year survey was carried out to record immediate outcome data of all EMRs performed, regardless of lesion size or gastrointestinal location.

RESULTS

Overall, 1335 EMRs in 1210 patients were reported by 241 of the 736 gastroenterologists who performed such procedures (33 %). Resections were done for upper gastrointestinal lesions in 125 cases (41 esophageal, 43 gastric, and 41 duodenal lesions), in 45 % of cases using specific EMR techniques such as ligation, cap, or traction. The technique for resecting the 1210 lower gastrointestinal lesions mostly consisted of saline-assisted polypectomy or EMR, with specific techniques used in only 2.2 %. En bloc resection was less common with esophageal (46 %) or duodenal (54 %) neoplasms than in the lower gastrointestinal tract (73 %); size also had some influence (53 % > 1 cm vs. 92 % ≤  1 cm). The overall complication rate was 5.2 %; the rate was lower for lesions 1 cm or smaller (0.6 % vs. 4.6 %). Fifty-four early and 17 delayed complications were recorded, in 12 % of upper gastrointestinal and 4.6 % of colonic lesions. Surgery became necessary in 1.6 % for upper and 2.9 % for lower gastrointestinal neoplasms. No association was seen between physician EMR caseload and either en bloc resection rate or complication rate.

CONCLUSIONS

EMR in general, especially saline-assisted polypectomy in the colon, appears to be reasonably safe even when performed by nonexperts. EMR for larger or for upper gastrointestinal lesions should probably be limited to high-volume centers.

Temporal horn enlargement is present in schizophrenia and bipolar disorder

BACKGROUND

Ventricular enlargement and temporal lobe volume deficits have been demonstrated in patients with affective disorder as well as those with schizophrenia. This study compares quantitative measures of temporal lobe, hemispheric, and ventricular volumes in a group of patients with chronic schizophrenia and bipolar disorder and seeks to determine if the groups can be differentiated on the basis of measured brain abnormalities.

METHODS

A series of coronal magnetic resonance imaging sections were acquired and analyzed for each of 22 patients with chronic schizophrenia, 14 patients with bipolar disorder, and 15 community volunteers. Eleven regions of interest for each brain were defined, which included temporal lobe, superior temporal gyrus, hemisphere, lateral ventricle, third ventricle, and temporal horn measures. Tissue measures were obtained by tracing, and cerebrospinal fluid measures were obtained by fluid-tissue thresholding using specialized computer software.

RESULTS

Both patient groups had significantly larger temporal horn volumes in comparison with the control group both before and after correction for intracranial volume. The two patient groups did not differ from each other or controls on any other tissue or fluid measure.

CONCLUSIONS

This study confirms the findings of increased temporal horn volume in patients with schizophrenia and suggests that this structural abnormality does not differentiate the structural neuropathology of schizophrenia from that of bipolar disorder.

Deficits in gray matter volume are present in schizophrenia but not bipolar disorder

Studies using magnetic resonance (MR) imaging have provided strong evidence that patients with schizophrenia as a group have structural brain abnormalities, including enlarged ventricles and sulci as well as smaller cortical gray matter volumes. This study was undertaken to investigate whether the brain abnormalities found in schizophrenia could be distinguished from those seen in bipolar disorder. The MR scans of 23 patients with schizophrenia were compared to those of 17 healthy community volunteers and 14 patients with bipolar disorder. Images were processed using computer-based image processing techniques to generate quantitative measures of cerebrospinal fluid (CSF), gray matter and white matter volumes. Compared to the community volunteers, the schizophrenia group had larger total CSF volumes while the bipolar group had larger ventricles. Smaller cortical gray matter volumes were found in the schizophrenia group, but not in the bipolar group. The schizophrenia group had regional deficits in gray matter volumes in comparison with both the community volunteers and the bipolar group. These findings suggest that the brain tissue abnormalities found in schizophrenia and bipolar disorder may be distinguishable using MR imaging.

Reproductive fitness in familial schizophrenia

BACKGROUND

Reproductive fitness is an important factor in understanding inheritance in genetic disorders. The purpose of this study was to determine whether fitness is reduced in familial schizophrenia (FS) and if fitness in siblings differs from the norm.

METHOD

The number of offspring in 36 subjects with RDC schizophrenia or schizoaffective disorder (SZ) and their 101 siblings from large FS families was compared with age-adjusted census figures.

RESULTS

Fitness in the SZ group was significantly reduced: 23% of expected in males and 51% of expected in females. Fitness of unaffected siblings was within census expectations. However, female siblings with schizophrenia spectrum features had increased fitness over census norms. Reduced fitness was correlated with low marital rates, poor functioning and positive symptoms.

CONCLUSIONS

These results indicate that reduced fitness is an important genetic force in FS and is likely inherent to the illness. Sex differences are important and would need to be considered when examining maternal and paternal transmission of schizophrenia. The results support a proposed high mutation rate for schizophrenia, consistent with a dynamic mutation mechanism.

Testing Liddle's three-syndrome model in families with schizophrenia

While the symptoms of schizophrenia can be grouped into positive and negative syndromes, increasing evidence suggests that three clusters of symptoms are present. Liddle (1987a) described a three-syndrome model comprised of reality distortion, psychomotor poverty and disorganization symptom clusters. This model was assessed in the present study using a sample of 72 members of five families segregating schizophrenia. A wide range of psychopathology was present across a spectrum of diagnoses. Data on symptoms used in Liddle's model were derived from the Positive and Negative Syndrome Scale (PANSS) and a mental status examination. Factor analysis of the data indicated the presence of three clusters of symptoms. The psychomotor poverty or negative symptom cluster was confirmed in the familial sample. However, the other two factors differed somewhat from the Liddle model. Hallucinations, delusions, disorganized thinking and inappropriate affect formed one factor; suspiciousness and stereotyped thinking formed the other. These three symptom clusters may be comparable to the catatonic, hebephrenic and paranoid classical subtypes of schizophrenia. The implications of Liddle's model for genetic studies of schizophrenia require further investigation.

Copying strategies and memory on the Complex Figure Test in psychiatric patients

We assessed three copying strategies on the Rey-Osterrieth Complex Figure Test among 50 psychiatric patients. The strategies were featural (detail-focused), contextual (framework-focused), and mixed. Reliable classification of each patient's copying strategy showed 7 patients used a featural and 7 patients used a contextual strategy. The remaining 36 used a mixed strategy involving both elements. Analysis indicated that patients who met DSM-III-R criteria for schizophrenia tended to use a mixed strategy. Nonschizophrenic patients also favoured the mixed approach. Moreover, when subjects were divided into groups based on their strategies, there were no differences in copying accuracy. However, the groups differed on immediate and delayed recall of the Complex Figure Test. Patients who adopted a featural strategy on the copy trial had the lowest recall scores. "Process" variables may be important in understanding neurocognitive functioning in schizophrenia; however, there is little evidence that schizophrenic patients use copying strategies consistent with lateralized impairment of brain function.

Metal complexes of antiinflammatory drugs. Part VII: Salsalate complex of copper(II)

The preparation and properties of the Cu(II) complex Cu(SAS)2.H2O are reported for the antiinflammatory drug Salsalate (SAS). The diffuse reflectance spectra and magnetic moments are consistent with a dinuclear structure as found for [Cu(aspirinate)2(H2O)]2. The Cu(II) complex exhibits an increased superoxide dismutase activity compared with the parent drug molecule in the nitroblue tetrazolium assay.