Toxic gain of function from mutant FUS protein is crucial to trigger cell autonomous motor neuron loss

FUS is an RNA‐binding protein involved in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Cytoplasmic FUS‐containing aggregates are often associated with concomitant loss of nuclear FUS. Whether loss of nuclear FUS function, gain of a cytoplasmic function, or a combination of both lead to neurodegeneration remains elusive. To address this question, we generated knockin mice expressing mislocalized cytoplasmic FUS and complete FUS knockout mice. Both mouse models display similar perinatal lethality with respiratory insufficiency, reduced body weight and length, and largely similar alterations in gene expression and mRNA splicing patterns, indicating that mislocalized FUS results in loss of its normal function. However, FUS knockin mice, but not FUS knockout mice, display reduced motor neuron numbers at birth, associated with enhanced motor neuron apoptosis, which can be rescued by cell‐specific CRE‐mediated expression of wild‐type FUS within motor neurons. Together, our findings indicate that cytoplasmic FUS mislocalization not only leads to nuclear loss of function, but also triggers motor neuron death through a toxic gain of function within motor neurons.     

Isoenzymmuster der Phosphoglucomutase der menschlichen Spermien (Sp.-PGM1)

Summary The isoenzyme patterns of phosphoglucomutase (PGM₁) were investigated in human spermatozoa (Sp.-PGM₁). The three phenotypes of PGM₁-polymorphism commonly found in erythrocytes could also be demonstrated in spermatozoa. It was also found that these patterns differ in spermatozoa quantitatively and in the case of phenotype PGM₁ 1-1 a qualitative difference could also be observed. The eventual significance of these findings in forensic medicine were briefly mentioned.     

Synthesis of 2-acetamido-2-deoxy-4-O-alpha-L-fucopyranosyl-alpha-D-glucopyranose]

Condensation of 2,3,4-tri-O-benzyl-alpha-L-fucopyranosyl bromide with benzyl 2-acetamido-3,6-di-O-benzyl-alpha-D-glucopyranoside in dichloromethane-N,N-dimethylformamide, in the presence of tetraethylammonium bromide, diisopropylethylamine, and molecular sieve (halide ion-catalyzed reaction), gave benzyl 2-acetamido-3,6-di-O-benzyl-2 deoxy-4-O-(2,3,4-tri-O-benzyl-alpha-L-fucopyranosyl)-alpha-D-glucopyranoside in crystalline form in 82% yield. Hydrogenolysis of the benzyl groups gave the title disaccharide, in crystalline form in 90% yield, which was characterized by a crystalline peracetylated alpha-D derivative.     

Structural characterization of sulfated glycosaminoglycans by fast atom bombardment mass spectrometry: application to heparin fragments prepared by chemical synthesis

We report herein the results of f.a.b.-m.s. experiments conducted on synthetic fragments of glycosaminoglycans, one of them representing the pentasaccharidic sequence present in heparin and responsible for the binding to antithrombin III, and the others being related to this sequence. The results indicate that f.a.b.-m.s. can be very useful for the structural analysis of sulfated glycosaminoglycans. The relatively small amounts of sample required enable molecular characterization at physiologically significant levels. In contrast to the chondroitin sulfates, the heparin saccharides analyzed and reported here do not provide sequence information. The data indicate that glycosidic rupture is not a process competing with the much more facile loss of N-sulfite residues. Dominating the spectra are a series of molecular-weight-related ions (distributed to indicate the associated countercation composition), and fragments related directly to sulfite elimination. This f.a.b.-induced, facile loss of sulfite may impose limitations in molecular-weight analysis for the larger oligomers.     

Chemical synthesis of the human blood-group P1-antigenic determinant

Condensation of known benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-4-O-(2,3,6-tri-O-benzyl-beta-D- galactopyranosyl)-alpha-D-glucopyranoside with 2,3,4,6-tetra-O-benzyl-alpha-D-galactopyranosyl chloride in dichloromethane in the presence of 2,4,6-trimethylpyridine, silver triflate, and molecular sieve 4A gave benzyl O-(2,3,4,6-tetra-O-benzyl-alpha-D-galactopyranosyl)-(1 leads to 4)-O-(2,3,6-tri-O-benzyl-beta-D-galactopyranosyl)-(1 leads to 4)-2-acetamido-3,6-di-O-benzyl-2-deoxy-alpha-D-glucopyranoside. Catalytic hydrogenolysis gave crystalline O-alpha-D-galactopyranosyl-(1 leads to 4)-O-beta-D-galactopyranosyl-(1 leads to 4)-2-acetamido-2-deoxy-alpha -D-glucopyranose, the human blood-group P1-antigenic determinant. A similar sequence of reactions was performed starting from allyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-beta-D-glucopyranoside, in order to prepare a derivative of this determinant suitable for linkage to carrier molecules.     

Mēthylation de dērivēs n-acylēs du 2-amino-2-dēsoxy-D-glucose en prēsence de sels d'argent: observations sur le comportement du groupement ambident acetamido (ou benzamido)

The behavior of the acetamido (and benzamido) ambident, nucleophilic group under methylation with methyl iodide and silver oxide has been studied for several 2-acetamido-2-deoxy-D-glucose derivatives. When silver perchlorate was added, alkylation occurred at the oxygen atom, giving methyl imidates that were labile in acidic medium. Benzyl 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-β-D-glucopyranoside was converted into N-(benzyl 3,4,6-tri-O-acetyl-2-deoxy-β-D-glucopyranoside-2-yl) methyl acetimidate (83%), which was subsequently hydrolyzed quantitatively in acidic medium into the corresponding amine salt. Similar results were obtained with benzyl 3,4,6-tri-O-acetyl-2-benzamido-2-deoxy-β-d-glucopyranoside, methyl 2-acetamido-2-deoxy-3,4,6-tri-O-methyl-β-D-glucopyranoside, and benzyl 2-acetamido-3,4,6-tri-O-benzyl-2-deoxy-β-D-glucopyranoside. Under Kuhn's methylation conditions (methyl iodide-silver oxide-N,N-dimethylformamide), alkylation of the just mentioned derivatives occurred at both oxygen and nitrogen atoms.     

Performance of the CareStart? G6PD Deficiency Screening Test,a Point-of-Care Diagnostic for Primaquine Therapy Screening

Development of reliable, easy-to-use, rapid diagnostic tests (RDTs) to detect glucose-6-phosphate dehydrogenase (G6PD) deficiency at point of care is essential to deploying primaquine therapies as part of malaria elimination strategies. We assessed a kit under research and development called CareStart™ G6PD deficiency screening test (Access Bio, New Jersey, USA) by comparing its performance to quantitative G6PD enzyme activity using a standardized spectrophotometric method (‘gold standard’). Blood samples (n = 903) were collected from Cambodian adults living in Pailin province, western Cambodia. G6PD enzyme activities ranged from 0 to 20.5 U/g Hb (median 12.0 U/g Hg). Based on a normal haemoglobin concentration and wild-type G6PD gene, the normal values of G6PD enzymatic activity for this population was 3.6 to 20.5 U/g Hg (95^th percentiles from 5.5 to 17.2 U/g Hg). Ninety-seven subjects (10.7%) had <3.6 U/g Hg and were classified as G6PD deficient. Prevalence of deficiency was 15.0% (64/425) among men and 6.9% (33/478) among women. Genotype was analyzed in 66 G6PD-deficient subjects and 63 of these exhibited findings consistent with Viangchang genotype. The sensitivity and specificity of the CareStart™ G6PD deficiency screening test was 0.68 and 1.0, respectively. Its detection threshold was <2.7 U/g Hg, well within the range of moderate and severe enzyme deficiencies. Thirteen subjects (1.4%, 12 males and 1 female) with G6PD enzyme activities <2 U/g Hg were falsely classified as “normal” by RDT. This experimental RDT test here evaluated outside of the laboratory for the first time shows real promise, but safe application of it will require lower rates of falsely “normal” results.