Amyloid A amyloidosis is a serious clinical condition resulting from the systemic deposition of amyloid A originating from serum amyloid A proteins with the kidneys being the most commonly and earliest affected organ. Previously described amyloid A amyloidosis is linked to increased production and deposition of serum amyloid A proteins secondary to inflammatory conditions arising from infectious, metabolic, or genetic causes. Here we describe a family with primary amyloid A amyloidosis due to a chr11:18287683 T>C (human genome version19) mutation in the SAA1 promoter linked to the amyloidogenic SAA1.1 haplotype. This condition leads to a doubling of the basal SAA1 promoter activity and sustained elevation of serum amyloid A levels that segregated in an autosomal dominant pattern in 12 genetically affected and in none of six genetically unaffected relatives, yielding a statistically significant logarithm of odds (LOD) score over 5. Affected individuals developed proteinuria, chronic kidney disease and systemic deposition of amyloid composed specifically of the SAA1.1 isoform. Tocilizumab (a monoclonal antibody against the interleukin-6 receptor) had a beneficial effect when prescribed early in the disease course. Idiopathic forms represent a significant and increasing proportion (15-20%) of all diagnosed cases of amyloid A amyloidosis. Thus, genetic screening of the SAA1 promoter should be pursued in individuals with amyloid A amyloidosis and no systemic inflammation, especially if there is a positive family history.
- MeSH
- amyloidóza * komplikace MeSH
- lidé MeSH
- mutace MeSH
- promotorové oblasti (genetika) MeSH
- sérový amyloid A genetika metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- genetická heterogenita * MeSH
- intranukleární inkluzní tělíska MeSH
- lidé MeSH
- neurodegenerativní nemoci * genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- dopisy MeSH
- komentáře MeSH
- práce podpořená grantem MeSH
Farber disease is a rare autosomal recessive disorder caused by acid ceramidase deficiency that usually presents as early-onset progressive visceral and neurologic disease. To understand the neurologic abnormality, we investigated behavioral, biochemical, and cellular abnormalities in the central nervous system of Asah1(P361R/P361R) mice, which serve as a model of Farber disease. Behaviorally, the mutant mice had reduced voluntary locomotion and exploration, increased thigmotaxis, abnormal spectra of basic behavioral activities, impaired muscle grip strength, and defects in motor coordination. A few mutant mice developed hydrocephalus. Mass spectrometry revealed elevations of ceramides, hydroxy-ceramides, dihydroceramides, sphingosine, dihexosylceramides, and monosialodihexosylganglioside in the brain. The highest accumulation was in hydroxy-ceramides. Storage compound distribution was analyzed by mass spectrometry imaging and morphologic analyses and revealed involvement of a wide range of central nervous system cell types (eg, neurons, endothelial cells, and choroid plexus cells), most notably microglia and/or macrophages. Coalescing and mostly perivascular granuloma-like accumulations of storage-laden CD68(+) microglia and/or macrophages were seen as early as 3 weeks of age and located preferentially in white matter, periventricular zones, and meninges. Neurodegeneration was also evident in specific cerebral areas in late disease. Overall, our central nervous system studies in Asah1(P361R/P361R) mice substantially extend the understanding of human Farber disease and suggest that this model can be used to advance therapeutic approaches for this currently untreatable disorder.
- MeSH
- časové faktory MeSH
- centrální nervový systém abnormality patologie MeSH
- chování zvířat MeSH
- Farberova nemoc komplikace patologie MeSH
- fenotyp MeSH
- homozygot MeSH
- hydrocefalus patologie MeSH
- kyselá ceramidasa metabolismus MeSH
- malformace nervového systému etiologie patologie MeSH
- mozeček patologie ultrastruktura MeSH
- myši transgenní MeSH
- myši MeSH
- neurony patologie ultrastruktura MeSH
- pohybová aktivita MeSH
- sfingolipidy metabolismus MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
- velký mozek patologie ultrastruktura MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Christianson syndrome (CS) is an X-linked neurodevelopmental and neurological disorder characterized in males by core symptoms that include non-verbal status, intellectual disability, epilepsy, truncal ataxia, postnatal microcephaly and hyperkinesis. CS is caused by mutations in the SLC9A6 gene, which encodes a multipass transmembrane sodium (potassium)-hydrogen exchanger 6 (NHE6) protein, functional in early recycling endosomes. The extent and variability of the CS phenotype in female heterozygotes, who presumably express the wild-type and mutant SLC9A6 alleles mosaically as a result of X-chromosome inactivation (XCI), have not yet been systematically characterized. Slc9a6 knockout mice (Slc9a6 KO) were generated by insertion of the bacterial lacZ/β-galactosidase (β-Gal) reporter into exon 6 of the X-linked gene. Mutant Slc9a6 KO male mice have been shown to develop late endosomal/lysosomal dysfunction associated with glycolipid accumulation in selected neuronal populations and patterned degeneration of Purkinje cells (PCs). In heterozygous female Slc9a6 KO mice, β-Gal serves as a transcriptional/XCI reporter and thus facilitates testing of effects of mosaic expression of the mutant allele on penetrance of the abnormal phenotype. Using β-Gal, we demonstrated mosaic expression of the mutant Slc9a6 allele and mosaically distributed lysosomal glycolipid accumulation and PC pathology in the brains of heterozygous Slc9a6 KO female mice. At the behavioral level, we showed that heterozygous female mice suffer from visuospatial memory and motor coordination deficits similar to but less severe than those observed in X-chromosome hemizygous mutant males. Our studies in heterozygous Slc9a6 KO female mice provide important clues for understanding the likely phenotypic range of Christianson syndrome among females heterozygous for SLC9A6 mutations and might improve diagnostic practice and genetic counseling by helping to characterize this presumably underappreciated patient/carrier group.
- MeSH
- alely MeSH
- ataxie genetika MeSH
- chování zvířat MeSH
- epilepsie genetika MeSH
- fenotyp MeSH
- G(M2) gangliosid imunologie MeSH
- genetické nemoci vázané na chromozom X genetika MeSH
- genotyp MeSH
- heterozygot MeSH
- kognitivní poruchy genetika MeSH
- mentální retardace genetika MeSH
- mikrocefalie genetika MeSH
- modely nemocí na zvířatech MeSH
- mozaicismus * MeSH
- mutace MeSH
- myši knockoutované MeSH
- myši MeSH
- Na(+)-H(+) antiport genetika fyziologie MeSH
- poruchy hybnosti oka genetika MeSH
- Purkyňovy buňky cytologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
Human acid alpha-glucosidase (GAA, EC 3.2.1.20) is a lysosomal enzyme that belongs to the glycoside hydrolase family 31 (GH31) and catalyses the hydrolysis of alpha-1,4- and alpha-1,6-glucosidic linkages at acid pH. Hereditary deficiency of GAA results in lysosomal glycogen storage disease type II (GSDII, Pompe disease). The aim of this study was to assess GH31 proteins in Caenorhabditis elegans (C. elegans) to identify the ortholog of human GAA. Bioinformatic searches for GAA ortholog in C. elegans genome revealed four acid alpha-glucosidase-related (aagr-1-4) genes. Multiple sequence alignment of AAGRs with other GH31 proteins demonstrated their evolutionary conservation. Phylogenetic analyses suggested clustering of AAGR-1 and -2 with acid-active and AAGR-3 and -4 with neutral-active GH31 enzymes. In order to prove the AAGRs' predicted alpha-glucosidase activity, we performed RNA interference of all four aagr genes. The impact on the alpha-glucosidase activity was evaluated at pH 4.0 (acid) and pH 6.5 (neutral), with or without the inhibitor acarbose. AAGR-1 and -2 expressed acidic alpha-glucosidase activity; on the contrary, AAGR-3 not -4 represented the predominant neutral alpha-glucosidase activity in C. elegans. Similar results were obtained in each of aagr-1 and -4 deletion mutants. Moreover, based on our structural models of AAGRs and these biochemical experiments, we hypothesize that the enzymatic sensitivity of AAGR-2 and human maltase-glucoamylase to the inhibitor acarbose is associated with a tyrosine residue in the GH31 active site, whereas acarbose resistance of AAGR-1 and human GAA is associated with the corresponding tryptophane in the active site. Acid-active AAGR-1 may thus represent the ortholog of human GAA in C. elegans.
- MeSH
- akarbóza farmakologie MeSH
- alfa-glukosidasy chemie genetika MeSH
- fylogeneze MeSH
- inhibitory glykosidových hydrolas MeSH
- katalytická doména MeSH
- lidé MeSH
- proteiny Caenorhabditis elegans antagonisté a inhibitory chemie genetika MeSH
- sekvenční seřazení MeSH
- výpočetní biologie metody MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
A neuropathologic study of three cases of prosaposin (pSap) deficiency (ages at death 27, 89 and 119 days), carried out in the standard autopsy tissues, revealed a neurolysosomal pathology different from that in the non-neuronal cells. Non-neuronal storage is represented by massive lysosomal accumulation of glycosphingolipids (glucosyl-, galactosyl-, lactosyl-, globotriaosylceramides, sulphatide, and ceramide). The lysosomes in the central and peripheral neurons were distended by pleomorphic non-lipid aggregates lacking specific staining and autofluorescence. Lipid storage was borderline in case 1, and at a low level in the other cases. Neurolysosomal storage was associated with massive ubiquitination, which was absent in the non-neuronal cells and which did not display any immunohistochemical aggresomal properties. Confocal microscopy and cross-correlation function analyses revealed a positive correlation between the ubiquitin signal and the late endosomal/lysosomal markers. We suppose that the neuropathology most probably reflects excessive influx of non-lipid material (either in bulk or as individual molecules) into the neurolysosomes. The cortical neurons appeared to be uniquely vulnerable to pSap deficiency. Whereas in case 1 they populated the cortex, in cases 2 and 3 they had been replaced by dense populations of both phagocytic microglia and astrocytes. We suggest that this massive neuronal loss reflects a cortical neuronal survival crisis precipitated by the lack of pSap. The results of our study may extend the knowledge of the neurotrophic function of pSap, which should be considered essential for the survival and maintenance of human cortical neurons.
- MeSH
- antigeny diferenciační myelomonocytární metabolismus MeSH
- CD antigeny metabolismus MeSH
- dítě MeSH
- financování organizované MeSH
- gliový fibrilární kyselý protein metabolismus MeSH
- glykosfingolipidy metabolismus MeSH
- lidé MeSH
- lyzozomální nemoci z ukládání metabolismus patologie MeSH
- lyzozomy metabolismus patologie MeSH
- molekuly buněčné adheze neuronové metabolismus MeSH
- mozková kůra patologie MeSH
- neurony patologie ultrastruktura MeSH
- novorozenec MeSH
- pitva MeSH
- saposiny fyziologie nedostatek MeSH
- ubikvitin metabolismus MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- mužské pohlaví MeSH
- novorozenec MeSH
- Publikační typ
- kazuistiky MeSH
- MeSH
- Creutzfeldtova-Jakobova nemoc diagnóza etiologie genetika MeSH
- encefalopatie bovinní spongioformní diagnóza genetika klasifikace MeSH
- financování vládou MeSH
- genomika metody MeSH
- geny genetika imunologie MeSH
- lidé MeSH
- polymerázová řetězová reakce metody využití MeSH
- priony analýza genetika izolace a purifikace MeSH
- proteiny nervové tkáně analýza genetika izolace a purifikace MeSH
- sekvenční analýza metody využití MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- kazuistiky MeSH
