Exclusive neuronal expression of SUCLA2 in the human brain

SUCLA2 encodes the ATP-forming subunit (A-SUCL-) of succinyl-CoA ligase, an enzyme of the citric acid cycle. Mutations in SUCLA2 lead to a mitochondrial disorder manifesting as encephalomyopathy with dystonia, deafness and lesions in the basal ganglia. Despite the distinct brain pathology associated with SUCLA2 mutations, the precise localization of SUCLA2 protein has never been investigated. Here we show that immunoreactivity of A-SUCL- in surgical human cortical tissue samples was present exclusively in neurons, identified by their morphology and visualized by double labeling with a fluorescent Nissl dye. A-SUCL- immunoreactivity co-localized >99% with that of the d subunit of the mitochondrial F0-F1 ATP synthase. Specificity of the anti-A-SUCL- antiserum was verified by the absence of labeling in fibroblasts from a patient with a complete deletion of SUCLA2. A-SUCL- immunoreactivity was absent in glial cells, identified by antibodies directed against the glial markers GFAP and S100. Furthermore, in situ hybridization histochemistry demonstrated that SUCLA2 mRNA was present in Nissl-labeled neurons but not glial cells labeled with S100. Immunoreactivity of the GTP-forming subunit (G-SUCL-) encoded by SUCLG2, or in situ hybridization histochemistry for SUCLG2 mRNA could not be demonstrated in either neurons or astrocytes. Western blotting of post mortem brain samples revealed minor G-SUCL- immunoreactivity that was however, not upregulated in samples obtained from diabetic versus non-diabetic patients, as has been described for murine brain. Our work establishes that SUCLA2 is expressed exclusively in neurons in the human cerebral cortex

Rapid identification of mutations in GJC2 in primary lymphoedema using whole exome sequencing combined with linkage analysis with delineation of the phenotype.

Background: Primary lymphoedema describes a chronic, frequently progressive, failure of lymphatic drainage. This disorder is frequently genetic in origin, and a multigenerational family in which eight individuals developed postnatal lymphoedema of all four limbs was ascertained from the joint Lymphoedema/Genetic clinic at St George's Hospital. Methods: Linkage analysis was used to determine a locus, and exome sequencing was employed to look for causative variants. Results: Linkage analysis revealed cosegregation of a 16.1 Mb haplotype on chromosome 1q42 that contained 173 known or predicted genes. Whole exome sequencing in a single affected individual was undertaken, and the search for the causative variant was focused to within the linkage interval. This approach revealed two novel non-synonymous single nucleotide substitutions within the chromosome 1 locus, in NVL and GJC2. NVL and GJC2 were sequenced in an additional cohort of individuals with a similar phenotype and non-synonymous variants were found in GJC2 in four additional families. Conclusion: This report demonstrates the power of exome sequencing efficiently applied to a traditional positional cloning pipeline in disease gene discovery, and suggests that the phenotype produced by GJC2 mutations is predominantly one of 4 limb lymphoedema

Leupaxin Expression Is Dispensable for B Cell Immune Responses.

The generation of a potent humoral immune response by B cells relies on the integration of signals induced by the B cell receptor, toll-like receptors and both negative and positive co-receptors. Several reports also suggest that integrin signaling plays an important role in this process. How integrin signaling is regulated in B cells is however still partially understood. Integrin activity and function are controlled by several mechanisms including regulation by molecular adaptors of the paxillin family. In B cells, Leupaxin (Lpxn) is the most expressed member of the family and in vitro studies suggest that it could dampen BCR signaling. Here, we report that Lpxn expression is increased in germinal center B cells compared to naïve B cells. Moreover, Lpxn deficiency leads to decreased B cell differentiation into plasma cells in vitro. However, Lpxn seems dispensable for the generation of a potent B cell immune response in vivo. Altogether our results suggest that Lpxn is dispensable for T-dependent and T-independent B cell immune responses

Model evaluation for glycolytic oscillations in yeast biotransformations of xenobiotics

Anaerobic glycolysis in yeast perturbed by the reduction of xenobiotic ketones is studied numerically in two models which possess the same topology but different levels of complexity. By comparing both models' predictions for concentrations and fluxes as well as steady or oscillatory temporal behavior we answer the question what phenomena require what kind of minimum model abstraction. While mean concentrations and fluxes are predicted in agreement by both models we observe different domains of oscillatory behavior in parameter space. Generic properties of the glycolytic response to ketones are discussed

Linkage and sequence analysis indicate that CCBE1 is mutated in recessively inherited generalised lymphatic dysplasia

Generalised lymphatic dysplasia (GLD) is characterised by extensive peripheral lymphoedema with visceral involvement. In some cases, it presents in utero with hydrops fetalis. Autosomal dominant and recessive inheritance has been reported. A large, non-consanguineous family with three affected siblings with generalised lymphatic dysplasia is presented. One child died aged 5 months, one spontaneously miscarried at 17 weeks gestation, and the third has survived with extensive lymphoedema. All three presented with hydrops fetalis. There are seven other siblings who are clinically unaffected. Linkage analysis produced two loci on chromosome 18, covering 22 Mb and containing 150 genes, one of which is CCBE1. A homozygous cysteine to serine change in CCBE1 has been identified in the proband, in a residue that is conserved across species. High density SNP analysis revealed homozygosity (a region of 900 kb) around the locus for CCBE1 in all three affected cases. This indicates a likely ancestral mutation that is common to both parents; an example of a homozygous mutation representing Identity by Descent (IBD) in this pedigree. Recent studies in zebrafish have shown this gene to be required for lymphangiogenesis and venous sprouting and are therefore supportive of our findings. In view of the conserved nature of the cysteine, the nature of the amino acid change, the occurrence of a homozygous region around the locus, the segregation within the family, and the evidence from zebrafish, we propose that this mutation is causative for the generalised lymphatic dysplasia in this family, and may be of relevance in cases of non-immune hydrops fetalis

Impacts of electric vehicle charging on distribution networks in Denmark

2011-2012 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Mutations in GATA2 cause primary lymphedema associated with a predisposition to acute myeloid leukemia (Emberger syndrome).

We report an allelic series of eight mutations in GATA2 underlying Emberger syndrome, an autosomal dominant primary lymphedema associated with a predisposition to acute myeloid leukemia. GATA2 is a transcription factor that plays an essential role in gene regulation during vascular development and hematopoietic differentiation. Our findings indicate that haploinsufficiency of GATA2 underlies primary lymphedema and predisposes to acute myeloid leukemia in this syndrome