Heparan sulfate expression in polarized epithelial cells: the apical sorting of glypican (GPI-anchored proteoglycan) is inversely related to its heparan sulfate content.

Several processes that occur in the luminal compartments of the tissues are modulated by heparin-like polysaccharides. To identify proteins responsible for the expression of heparan sulfate at the apex of polarized cells, we investigated the polarity of the expression of the cell surface heparan sulfate proteoglycans in CaCo-2 cells. Domain-specific biotinylation of the apical and basolateral membranes of these cells identified glypican, a GPI-linked heparan sulfate proteoglycan, as the major source of apical heparan sulfate. Yet, most of this proteoglycan was expressed at the basolateral surface, an unexpected finding for a glypiated protein. Metabolic labeling and chase experiments indicated that sorting mechanisms, rather than differential turnover, accounted for this bipolar expression of glypican. Chlorate treatment did not affect the polarity of the expression of glypican in CaCo-2 cells, and transfectant MDCK cells expressed wild-type glypican and a syndecan-4/glypican chimera also in an essentially unpolarized fashion. Yet, complete removal of the heparan sulfate glycanation sites from the glypican core protein resulted in the nearly exclusive apical targeting of glypican in the transfectants, whereas two- and one-chain mutant forms had intermediate distributions. These results indicate that glypican accounts for the expression of apical heparan sulfate, but that glycanation of the core protein antagonizes the activity of the apical sorting signal conveyed by the GPI anchor of this proteoglycan. A possible implication of these findings is that heparan sulfate glycanation may be a determinant of the subcellular expression of glypican. Alternatively, inverse glycanation-apical sorting relationships in glypican may insure near constant deliveries of HS to the apical compartment, or "active" GPI-mediated entry of heparan sulfate into apical membrane compartments may require the overriding of this antagonizing effect of the heparan sulfate chains.

Differential expression of multiple cell-surface heparan sulfate proteoglycans during embryonic tooth development.

Heparan sulfate accumulates on cell surfaces and at cell-matrix interfaces, and functionally modulates several of the effector molecules that support the interactions, growth, and differentiation of developing tissues. Using heparin sulfate-specific monoclonal antibodies MAb, we obtained evidence that extracts from rodent embryos contain multiple forms of cell surface-associated heparan sulfate proteoglycan (PG). Taking tooth development in the mouse embryo as a model to further investigate the relevance of this PG redundancy and using MAb against heparan sulfate, antibodies specific for syndecan (syndecan-1) and fibroglycan (syndecan-2) (two distinct members of a larger family of cell-surface heparan sulfate PGs), and specific cDNA probes for these two cell-surface PGs, we obtained in situ evidence for regulated and differential expression of multiple cell-surface heparan sulfate PGs. The unique, distinctive, and coordinated changes in the expressions of these PGs during morphogenesis and differentiation of dental tissues suggest that the various cell-surface PGs are not truly redundant but play important, specific, and potentially complementary roles during embryonic development.

Cohen syndrome and de novo reciprocal translocation t(5;7)(q33.1;p15.1).

Here we report on a de novo apparently balanced reciprocal 5q;7p translocation in a 15-year-old girl with apparent Cohen syndrome characterized by hypotonia, obesity, multiple congenital anomalies, and mental retardation. This case may indicate that the gene for Cohen syndrome is at 5q33.1 or 7p15.1.

Ectomorphic habitus, severe mental retardation and characteristic face: a new MCA/MR syndrome?

Here we report on 2 mentally retarded sisters with clinical signs and symptoms not seen in a previously delineated MCA/MR syndrome, i.e., normal pre- and perinatal history, severe mental retardation with severe delay in psychomotor development and without development of primary motor abilities and speech, characteristic face with maxillary hypoplasia, large mouth with down-turned corners, short philtrum and everted lower lip, associated with a remarkable ectomorphic habitus.

Hallermann-Streiff syndrome: clinical and psychological findings in children. Nosologic overlap with oculodentodigital dysplasia?

We describe 3 young children with Hallermann-Streiff syndrome, 2 with typical manifestations and 1 with the facial changes without the eye abnormalities but with a cleft palate and with complete syndactyly of fingers IV and V. The latter case represents overlap of the Hallermann-Streiff syndrome and oculodentodigital dysplasia. "Dwarfism" as a possible clinical risk marker of mental retardation is discussed. As cause, a mendelian autosomal dominant mutation seems most probable.

Chromosome abnormalities in cementifying fibroma.

Cementifying fibroma is the most frequent benign fibro-osseous odontogenic tumor. We found chromosome abnormalities in a second case of this type of benign tumor. The chromosome changes in both cases are different. The chromosome bands involved in our case have not been described before in any benign fibroma so far reported.

Nager acrofacial dysostosis. An adult male with severe neurological deficit.

In this report we describe a 50-year old male with Nager Acrofacial Dysostosis. In addition to the typical maxillofacial dysostosis and the bilateral thumb hypoplasia, he presented a severe neurological syndrome with spastic diplegia, hemiparesis of the left arm, and agenesis of the corpus callosum on CT-scan. He died at the age of 50 years from congestive heart failure due to a complete AV-block.

[Chromosome X-linked mental retardation and marfanoid syndrome]. / Retard mental lié au chromosome X et syndrome marfanoïde.

In the present paper we report two pairs of slightly to moderately mentally retarded brothers with Marfanoid habitus and similar craniofacial changes. They had a long and narrow face, small mandible, high-arched palate and hypernasal voice, as previously reported by Lujan et al. (1984) in 4 mentally retarded males of a large kindred. The present data suggest the existence of a specific type of X-linked mental retardation with Marfanoid habitus.

Sex-linked recessive inheritance in Charcot-Marie-tooth disease with partial clinical manifestations in female carriers.

A large kindred with sex-linked recessive inheritance of Charcot-Marie-Tooth disease is presented. Partial clinical manifestations without functional disability and decreased nerve conduction velocity was demonstrated in the female heterozygotes.

Partial trisomy of the short arm of chromosome 3 (3p25 to 3pter). A distinct clinical entity.

Two profoundly mentally retarded brothers with partial trisomy for the distal part of the short arm of chromosome 3 (3p25 to 3pter) are described. Their anomaly arose as a segregation product of a balanced t(3p-;18q+) translocation in the mother. Compared with the other cases of partial 3p trisomy reported up to now, the present patients display a similar craniofacial dysmorphism with hypertelorism, broad nasal tip, short upper lip with prominent philtrum, and a large mouth with down-turned corners. Other stigmata, such as a prominent, high forehead with frontal bossing and full cheeks, were present during childhood but progressively disappeared.

The Cohen syndrome.

A 9.5-year old severely mentally retarded boy is reported with the typical features of the Cohen syndrome. It is emphasized that this syndrome be differentiated from other constitutional syndromes featuring mental retardation, obesity short stature and hypotonia, because of a different genetic prognosis. Compared to the Prader-Labhart-Willi syndrome the craniofacial appearance of this autosomal recessively inherited malformation syndrome is characterised by antimongoloid position of the eyes, dental anomalies with prominent upper incisors and malocclusion, and high-arched palate. Ocular anomalies mostly include pigmentary retinal anomalies. Whereas hypotonia is severe from the beginning, obesity becomes only striking after the age of 5 years.

MCA/MR syndrome with features of Hallermann-Streiff syndrome and 4q deficiency/14q duplication.

In this report we present the clinical history and findings in a female newborn with 4q deficiency/14q duplication, the unbalanced product of a paternal t(4;14)(q33;q32). The clinical symptoms and signs observed in this child up to the age of 14 months were most compatible with the diagnosis of Hallermann-Streiff syndrome.

Distal 11q deletion: a specific clinical entity.

In this report we describe a male newborn with a deletion of the distal part of the long arm of chromosome 11 (46,XY,del(11)(q23.1----qter). In addition to the typical craniofacial changes of the distal 11q monosomy syndrome, i.e. trigonocephaly, short nose with upturned nares, and large mouth with downturned corners, this male newborn presented a number of peculiar additional anomalies: extremely short neck, accessory nipples and camptodactyly of all fingers. The clinical findings are in agreement with the fact that deletion of the 11q24.1 subband is essential for the characteristic phenotype, and that the additional anomalies are due to deletion of the more proximal 11q23 band.

Multiple distinct membrane heparan sulfate proteoglycans in human lung fibroblasts.

Heparitinase digestion of the hydrophobic membrane-associated heparan sulfate proteoglycans (HSPG) of fetal human lung fibroblasts yields core proteins of various sizes: i.e. monomeric core proteins of 125, 90, 64, 48, and 35 kDa and a disulfide-linked dimeric core protein composed of approximately 35-kDa subunits. By immunizing BALB/c mice with liposome-incorporated HSPG, we have obtained a total of five anti-HSPG monoclonal antibodies (Mabs, i.e. Mabs S1, 1C7, 2E9, 6G12, and 10H4) with different specificities. Polyacrylamide gel electrophoresis of 125I-labeled membrane HSPG immunoprecipitated with these Mabs revealed that Mabs 1C7 and 2E9 bind only membrane HSPG which yield a 125-kDa core protein after heparitinase digestion, whereas Mab S1-bound HSPG yield a 64-kDa core protein, and Mabs 6G12 and 10H4 retain membrane HSPG with a 48-kDa core protein. Western blotting of the heparitinase-digested proteoglycans and immunostaining with the Mabs confirmed this pattern of reactivity. However, in this assay, Mabs 6G12 and 10H4 also detected a minor approximately 90-kDa core protein in addition to the 48-kDa core protein. Except perhaps for the 10H4 epitope, the epitopes recognized by these Mabs appear to be part of the peptide moieties as they resisted complete deglycosylation of the HSPG with trifluoromethanesulfonic acid. Since these data were inconsistent with a direct relationship between the major core proteins, the 48-, 64-, and 125-kDa core proteins were immunopurified and further compared by peptide mapping with Staphylococcus aureus protease V8, trypsin, and CNBr cleavage. Clearly distinct peptide patterns were obtained for the three different core proteins. These results imply that the 48-, 64-, and the 125-kDa membrane HSPG core proteins of human lung fibroblasts are derived from distinct proteoglycans.

Heparan sulfate proteoglycans of human lung fibroblasts. Occurrence of distinct membrane, matrix and secreted forms.

Human lung fibroblasts (HLF) were labeled with 35SO2-4 for 48 h and extracted with a guanidinium chloride buffer. A fraction of the extracted heparan sulfate proteoglycan (HSPG) appeared micelle-associated. In the absence of detergent these HSPG eluted in the void volume of Sepharose CL2B columns. In the presence of detergent these HSPG were included in Sepharose CL2B (Kav = 0.55) and 4B (Kav = 0.3) columns. This type of HSPG was specifically associated with isolated HLF cell membranes, suggesting that it may represent a fraction of integral membrane proteoglycans. Most of the HSPG in the HLF monolayers, however, eluted in the included volume of Sepharose CL2B (Kav = 0.4) and CL4B (Kav = 0.1) columns in the absence of detergent. This type of HSPG was not affected by detergent and was specifically retained in 'extracellular matrix' preparations. The medium of HLF monolayers contained HSPG of similar Mr as the membrane-associated HSPG. Of these three distinct HSPG fractions only the membrane-associated form could be incorporated in liposomes, confirming that the HSPG in this fraction may be integral membrane components.

Severe pre- and postnatal growth retardation, developmental delay with hypotonia and marked hypotrophy of the distal extremities, dental anomalies, and eczematous skin. A new autosomal recessive entity.

We report on three young children, two girls and one boy, with pre- and postnatal growth deficiency, hypotonia, psychomotor retardation with notably impaired speech development, hypotrophy of the distal extremities, small hands and feet, small and widely spaced teeth, eczematous skin, and, in two of them, a partial agenesis of the corpus callosum. To our knowledge this specific combination of features has not been reported before. Since the two girls are sisters and the boy is the product of a consanguineous marriage, the inheritance of this new syndrome appears to be autosomal recessive.

Solubilization and affinity purification of the alpha 2-macroglobulin receptor from human fibroblasts.

Plasma membranes showing specific binding of alpha 2-macroglobulin (alpha 2M) complexes were isolated from normal human fibroblasts. The membrane preparation was solubilized with Triton X-100, and specific binding to solubilized receptor was demonstrated by precipitation of the alpha 2M X protease receptor complexes with polyethylene glycol. The solubilized receptor could be quantitatively adsorbed on immobilized alpha 2M complexes. Adsorbed receptor was then dissociated from the alpha 2M complexes with either EDTA, bacitracin, the monoclonal anti-receptor-recognition site antibody F2B2 , or low pH. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the affinity-purified receptor preparation revealed polypeptides of 360, 130, and 83 kDa.

EEC syndrome without ectrodactyly: report of two new families.

In this report we describe two families with variable manifestations of the EEC syndrome. The findings in these families confirm that no symptom is obligatory for the diagnosis of EEC syndrome. In the absence of cleft lip/palate, EEC patients have a characteristic facial morphology with maxillary hypoplasia, short philtrum, and broad nasal tip.