Molecular basis of Sotos syndrome

This paper describes the isolation of a novel human gene, NSD1, from the 5q35 breakpoint of t(5;8)(q35; q24.1) in a patient with Sotos syndrome, and NSD1 mutation analysis. Of 112 (95 Japanese and 17 non-Japanese) patients analyzed, 16 (14%) had a heterozygous NSD1 point mutation (10 protein truncation types and six missense types) and 50 (45%) a approximately 0.7-Mb microdeletion involving NSD1. The results indicated that haploinsufficiency of NSD1 is the major cause of Sotos syndrome, and NSD1 plays a role in growth and brain development in humans. Detailed clinical examinations provided a genotype-phenotype correlation in Sotos syndrome, i.e. in patients with deletions, overgrowth is less obvious and mental retardation is more severe than in those with point mutations, and major anomalies were exclusively seen in the former. The results also indicated that Sotos syndrome due to a deletion falls into a contiguous gene syndrome, while Sotos syndrome due to an NSD1 point mutation is a single gene defect, occasionally with an autosomal dominant mode of inheritance. The genomic structure around the deleted and flanking regions revealed the presence of two sets of low copy repeats through which the microdeletion in Sotos syndrome is mediated.     

Effects of specific signal transduction inhibitors on increased permeability across rat endothelial monolayers induced by neuropeptide Y or VEGF

Neuropeptide Y (NPY) elevates the permeability of cultured rat aortic endothelial cells (RAECs) in monolayer cultures under hypoxic conditions (5% O(2)) possibly by binding to the NPY Y(3) receptor. The present study evaluated the effects of NPY compared to vascular endothelial growth factor (VEGF). RAECs were cultured on the upper chamber base of a double-chamber culture system, FITC-labeled albumin was introduced into the chamber, and permeation into the lower chamber was measured. Treatment was with 3 x 10(-7) M NPY or 10(-7) g/ml VEGF for 2 h along with specific inhibitors. The VEGF receptor-2 tyrosine kinase inhibitor tyrphostin SU-1498 and the protein kinase C inhibitor bis-indolylmaleimide I (GF-109203X) suppressed the VEGF-induced increase in monolayer permeability but not that caused by NPY. Furthermore, although the action of NPY was blocked in a concentration-dependent manner by phospholipase C inhibitor 1-(6-[[(17beta)-3-methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl)-1H-pyrrole-2,5-dione (U-73122), it was less sensitive than VEGF. However, the effects of both NPY and VEGF on the permeability of the RAEC monolayer were blocked with equal concentration dependence by STI571 (imatinib mesylate), which is an inhibitor of Abl tyrosine kinase in the nucleus and/or cytoplasm. The myosin light-chain kinase inhibitor 1-(5-chloronaphthalene-1-sulfonyl)-1H-hexahydro-1,4-diazepine HCl (ML-9) suppressed both NPY- and VEGF-induced increment in permeability by approximately 70%, whereas the calmodulin-dependent kinase inhibitor DY-9760e could decrease to below the baseline. These results indicate that the NPY Y(3)-receptor subtype is specifically linked to the effects of STI571 on endothelial cells, and that NPY, a sympathetic coneurotransmitter, may increase vascular permeability in association with altered intracellular or nuclear signal transduction.     

Saturated glucose uptake capacity and impaired fatty acid oxidation in hypertensive hearts before development of heart failure

Abnormalities in energy metabolism may play an important role in the development of hypertensive heart failure. However, the transition from compensated hypertrophy to heart failure is not fully understood in terms of energy metabolism. In Dahl salt-sensitive (DS) and salt-resistant (DR) rats, myocardial fatty acid and glucose uptake values were determined using (131)I- or (125)I-labeled 9-methylpentadecanoic acid ((131)I- or (125)I-9MPA), and [(14)C]deoxyglucose ([(14)C]DG), fatty acid beta-oxidation was identified using thin-layer chromatography, and insulin-stimulated glucose-uptake was observed using a euglycemic hyperinsulinemic glucose clamp. Six-week-old rats were fed a diet that contained 8% NaCl, which resulted in development of compensated hypertrophy in DS rats at 12 wk of age and ultimately led to heart failure by 18 wk of age. Uptake of [(14)C]DG increased markedly with age in the DS rats, whereas (131)I-9MPA uptake was marginally but significantly increased only in animals aged 12 wk. The ratio of (125)I-9MPA beta-oxidation metabolites to total uptake in the DS rats was significantly lower (P < 0.05) at 12 (37%) and 18 (34%) wk compared with at 6 (45%) wk. Insulin increased [(14)C]DG uptake more than twofold in the DS rats at 6 wk, although this increase was markedly attenuated at 12 and 18 wk (11 and 8%, respectively). Our data suggest that in a hypertrophied heart before heart failure, fatty acid oxidation is impaired and the capacity to increase glucose uptake during insulin stimulation is markedly reduced. These changes in both glucose and fatty acid metabolism that occur in association with myocardial hypertrophy may have a pathogenic role in the subsequent development of heart failure.     

Role of follicular dendritic cells in the early HIV-1 infection: in vitro model without specific antibody

About 90% of HIV-1 RNA in the lymph nodes is reported to localize in follicular dendritic cellsnetwork (FDC-NW) as early as several days after infection and as much as that in the late stage. But the mechanism remains to be fully understood. To elucidate the role of follicular dendritic cells (FDC) in the early stage of HIV-1 infection, FDC-like cell strains (FDCLC) were established and they were characterized in the co-culture system with T cells for their effect on HIV-1 trapping and replication in p24 immunoassay, immunohistochemistry as well as confocal and electronmicroscopy. Established FDCLC were positive for CNA-42, S-100alpha and intercellular desmosome-like junctions. L-SIGN and DC-SIGN were also detected in FDCLC. Alu-HIV-1 PCR analysis showed no HIV-1 integration in FDCLC. FDCLC trapped HIV-1 and transferred them to uninfected MOLT-4 T cells (MOLT-4) efficiently in the absence of specific antibody. FDCLC also accelerated HIV-1 replication in HIV-1-pre-exposed MOLT-4. These unique FDCLC effects were explained, at least partly, by the fact that FDCLC up-regulated CD4 expression in MOLT-4 and helped T cells escape from apoptosis in the co-culture. These data suggest that FDC/FDCLC engage not only in trapping but also in active expansion of HIV-1 in the absence of specific antibody.     

A highly bioactive lignophenol derivative from bamboo lignin exhibits a potent activity to suppress apoptosis induced by oxidative stress in human neuroblastoma SH-SY5Y cells

Approaches to protection against neurodegenerative diseases, in which oxidative stress and inflammation are implicated, should be based on the current concept on the etiology of these diseases. Recently, a new therapeutic strategy has been proposed to protect neurons from cell death by attenuating the apoptotic signal transduction. Lignin, a durable aromatic network polymer second to cellulose in abundance, was able to be converted into highly active lignophenol derivatives with antioxidant activity by using our newly developed phase-separation technique. These lignophenol derivatives were found to show the potent neuroprotective activity against oxidative stress. Among the compounds examined, a lignocresol derivative from bamboo (lig-8) exhibited the most potent neuroprotective activity against hydrogen peroxide (H(2)O(2))-induced apoptosis in human neuroblastoma cell line SH-SY5Y by preventing the caspase-3 activation via either caspase-8 or caspase-9. Furthermore, it was found that lig-8 exerted the antiapoptotic effect by inhibiting dissipation of the mitochondrial membrane permeability transition induced by H(2)O(2) or by the peripheral benzodiazepin receptor ligand PK11195. Lig-8 was also shown to be potent in the antioxidant activity in the cells exposed to H(2)O(2), as assessed by flow cytometry using 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate and in vitro reactive oxygen species-scavenging potency. These data suggest that lig-8 is a promising neuroprotector, which affects the signaling pathway of neuronal cell death and that it would be of benefit to delay the progress of neurodegenerative diseases.     

Clathrin isoform CHC22, a component of neuromuscular and myotendinous junctions, binds sorting nexin 5 and has increased expression during myogenesis and muscle regeneration

The muscle isoform of clathrin heavy chain, CHC22, has 85% sequence identity to the ubiquitously expressed CHC17, yet its expression pattern and function appear to be distinct from those of well-characterized clathrin-coated vesicles. In mature muscle CHC22 is preferentially concentrated at neuromuscular and myotendinous junctions, suggesting a role at sarcolemmal contacts with extracellular matrix. During myoblast differentiation, CHC22 expression is increased, initially localized with desmin and nestin and then preferentially segregated to the poles of fused myoblasts. CHC22 expression is also increased in regenerating muscle fibers with the same time course as embryonic myosin, indicating a role in muscle repair. CHC22 binds to sorting nexin 5 through a coiled-coil domain present in both partners, which is absent in CHC17 and coincides with the region on CHC17 that binds the regulatory light-chain subunit. These differential binding data suggest a mechanism for the distinct functions of CHC22 relative to CHC17 in membrane traffic during muscle development, repair, and at neuromuscular and myotendinous junctions.     

The Finnish Disease Heritage III: the individual diseases

This article is the third and last in a series entitled The Finnish Disease Heritage I-III. All the 36 rare hereditary diseases belonging to this entity are described for clinical and molecular genetic purposes, based on the Finnish experience gathered over a period of half a century. In addition, five other diseases are mentioned. They may be included in the list of the "Finnish diseases" after adequate complementary studies.