Purification and Properties of Bacterial Chondroitinases and Chondrosulfatases

Effect of enzyme digestion on the permeability barrier in keratinizing and non-keratinizing epithelia

In an attempt to characterize the permeability barrier of the oral mucosa and skin, small pieces of keratinized and non-keratinized oral epithelia and epidermis were digested with specific enzymes. These enzymes were selected for their effect on carbohydrate-protein, or carbohydrate-lipid compounds and phospholipids. The effect of the enzyme treatment was monitored by exposing the digested tissue to horseradish peroxidase. Electron microscopic examination of tissue treated with phospholipases revealed considerable damage to membrane structures but not to the integrity of the permeability barrier. Hyaluronidase and neuraminidase caused less structural damage but did not impair barrier function; this was only seen after treatment with chondroitinase ABC. This enzyme may degrade certain of the polar molecules thought to be necessary to stabilize the neutral lipid bilayers of the intercellular barrier and thus disrupt its barrier properties.

Determination of unsaturated glycosaminoglycan disaccharides by spectrophotometry on thin-layer chromatographic plates

Chondroitin sulfate isomers and hyaluronate, digested with chondroitinase AC II and separated as unsaturated disaccharides by thin-layer chromatography on cellulose, were quantitated with scanning spectrophotometry using reflectance measurement at 232 nm. The sensitivity of the assay was increased by one order of magnitude as compared to previous modifications of the disaccharide analysis on cellulose. The method allowed quantitation of 0.2-20 micrograms of glycosaminoglycan uronic acid. Since the elution of the disaccharides from the plate could be omitted, the speed and reproducibility of the assay was enhanced.

The effect of serum growth factors and xyloside on molecular aging of proteoglycan in embryonal chick cartilage

The effects of normal human serum, insulin-like growth factor and beta-D-xyloside on the synthesis of proteoglycan, as well as their differential effect on the synthesis of chondroitin sulfate and keratan sulfate side-chains, were studied in chick embryonal cartilage. The glycosaminoglycans found in the incubation medium were mainly intact carbohydrate moieties of partially degraded proteoglycan molecules, whereas the tissue-bound glycosaminoglycans were of intact proteoglycan molecules. In incubations with normal human serum, the synthesis of the chondroitin sulfate side-chains of the tissue-bound glycosaminoglycans was preferentially stimulated, while the percentage of medium glycosaminoglycan (out of the total glycosaminoglycan in tissue and medium) was reduced, compared to control incubations. In incubations with insulin-like growth factor, the synthesis of the keratan sulfate side-chains of the tissue-bound glycosaminoglycan was preferentially stimulated, whereas the percentage of the medium glycosaminoglycan resembled that of control incubations. In incubations with xyloside, a marked reduction of tissue-bound glycosaminoglycan was noticed, mainly of chondroitin sulfate chains, and only a slight decrease in keratan sulfate chains. Human serum of various age groups stimulated proteoglycan synthesis in embryonal chick cartilage to almost the same extent. However, sera from babies and adults were found to stimulate chondroitin sulfate chains preferentially, whereas serum of aged subjects preferentially enhanced the synthesis of keratan sulfate chains. These findings suggest that the synthesis and/or degradation of the various types of glycosaminoglycan chains (chondroitin sulfate and keratan sulfate) of cartilage proteoglycan can be regulated differentially by serum growth factors. Secondly, the growth hormone-mediated serum factor (insulin-like growth factor) seems to play a role in molecular aging of proteoglycans.

In vitro effects of insulin on macromolecular events in newt limb regeneration blastemata

This work provides data demonstrating a stimulatory effect of insulin on macromolecular events occurring in cultured regeneration blastemata and demonstrates a synergistic interdependence between nerves and insulin in newt limb regeneration. The current experiments provide evidence for the following: (1) Insulin is paramount for expression of the mitogenic effect of nerves on cultures blastemata. (2) Insulin stimulates the incorporation of (3H)uridine into the acid-insoluble fraction of blastemal homogenates, but it does not alter the turnover rate of incorporated labeled uridine. (3) Insulin also stimulates the incorporation of 35SO4 and (3H)leucine into both chondroitinase-sensitive and chondroitinase-resistant blastemal proteoglycans. (4) Insulin increases the uptake of radiolabeled precursors by the blastemata, namely, (3H)leucine, (3H)uridine, 35SO4, (3H)alpha-aminoisobutyrate, and (3H)2-deoxy-D-glucose. The importance of insulin in the regulation of newt limb regeneration is discussed.

Mapping by monoclonal antibody detection of glycosaminoglycans in connective tissues

Chondroitin sulphate proteoglycans are widespread connective tissue components and chemical analysis of cartilage and other proteoglycans has demonstrated molecular speciation involving the degree and position of sulphation of the carbohydrate chains. This may, in turn, affect the properties of the glycosaminoglycan (GAG), particularly with respect to self-association and interactions with other extracellular matrix components. Interactions with specific molecules from different connective tissue types, such as the collagens and their associated glycoproteins, could be favoured by particular charge organizations on the GAG molecule endowed by the sulphate groups. So far, it has not been possible to identify and map chondroitins of differing sulphation in tissues, but we have now raised three monoclonal antibodies which specifically recognize unsulphated, 4-sulphated and 6-sulphated chondroitin and dermatan sulphate. These provide novel opportunities to study the in vivo distribution of chondroitin sulphate proteoglycans. We demonstrate that chondroitin sulphates exhibit remarkable connective tissue specificity and furthermore provide evidence that some proteoglycans may predominantly carry only one type of chondroitin sulphate chain.

Fractionation and isolation of heparan sulfates using poly-L-lysine-Sepharose

A simple procedure for the isolation of heparan sulfates from pig lung using a poly-L-lysine-Sepharose column is described. Glycosaminoglycans are absorbed on poly-L-lysine-Sepharose at pH 7.5 and eluted with an NaCl linear gradient in the following order: hyaluronic acid (0.32 M NaCl), chondroitin (0.36 M NaCl), keratan sulfate (0.80 M NaCl), chondroitin 4-sulfate (0.86 M NaCl), chondroitin 6-sulfate (0.95 M NaCl), dermatan sulfate (0.91 M NaCl), heparan sulfate (1.2 M NaCl), and heparin (1.35 M NaCl). Based on these observations, isolation of heparan sulfate from pig lung crude heparan sulfate fractions which contain chondroitin sulfates and dermatan sulfate was attempted, using this chromatographic technique.

Extracellular matrix (ECM) proteoglycans produced by cultured bovine corneal endothelial cells

The nature of the proteoglycan(s) (PG) found in the extracellular matrix (ECM) layer produced by cultured bovine corneal endothelial (BCE) cells is analyzed. The PG(s) account for approximately 5 to 6% of the dry weight of the ECM, regardless of the amount of extracellular soluble PG available in the medium. A 4 M guanidinium chloride (GuCl) extract of ECM was separated on a dissociative cesium chloride (CsCl) gradient (1.25 g/cm3 starting density). Results showed one main peak of PG substance(s) comprising 91% of the total labelled substance and uronic acid, banding at a specific buoyant density of 1.29 g/cm3. The molecular weight of this major PG(s) as estimated by gel filtration on Sepharose CL-4B ranged from 0.5 to 0.7 X 10(6). Further chemical analysis of the main PG(s) band revealed a protein moiety accounting for 45% of the weight and carbohydrates-glycosaminoglycans (GAG) accounting for the remaining 55%. Analysis of the GAG chains (over the entire gradient) showed a composition, based on the susceptibility of the PG substance(s) to degrading enzymes, of 50% heparan sulfate, 43.5% dermatan sulfate, and 6.5% chondroitin 4- and 6-sulfate chains. BCE cell cultures grown in the presence of beta-D-xyloside produced an ECM lacking more than 90% of the GAG content found in the control ECM. The medium-soluble GAG chains, produced in vast excess in cultures grown in the presence of beta-D-xyloside, are composed mainly of chondroitin 4- and 6-sulfates.

Type, location and role of glycosaminoglycans in cloned differentiated chick retinal pigmented epithelium

In clonal culture, colonies of 3-4 week old chick retinal pigmented epithelial cells exhibit Alcian Blue positive extracellular matrix (ECM) material on the surface of the cells. Alcian blue positive ECM is located between undifferentiated cells at the edges of the disc-shaped colonies and beneath the differentiated cells in the colony center. The latter material is associated with the basement membrane. The staining properties suggest that glycosaminoglycans (GAG) are present in these regions. Extraction of GAG from homogenates of colonies, followed by electrophoresis on cellulose acetate strips, results in three bands with mobilities similar to those of hyaluronic acid, heparan sulfate, and chondroitin sulfate, respectively. All three bands label with [3H]glucosamine, and the last two also label with [35S]sulfate. The composition appeared to differ when colonies were grown in different media. Digestion of the GAG preparations with various enzymes suggests that bands II and III represent heparan sulfate and chondroitin sulfate, respectively, in colonies grown in Ham's F10g medium. The composition of band I is as yet undetermined. In minimal Eagle's medium (MEM), bands I and III consisted of hyaluronic acid and chondroitin sulfate, respectively, while band II had properties suggestive of a copolymer of heparan sulfate and an unidentified GAG. Cells release only one [3H]glucosamine-labelled GAG into the medium. This material has a mobility similar to hyaluronic acid and is digested by Streptomyces hyaluronidase, suggesting that it is hyaluronic acid. Staining with Alcian Blue at different pH suggests that it may represent the material associated with the upper surface of the cells. Some of the ECM located between the undifferentiated cells and associated with the basement membrane in the differentiated regions of the colonies stains with Alcian Blue at pH 1.0 and 0.2 suggesting that it may contain GAGs found in bands I and II. Colonies treated with medium containing 6-diazo-5-oxo-L-norleucine (DON), an inhibitor of GAG synthesis, for 48 hr showed a reduced Alcian Blue staining of the ECM in the undifferentiated regions. After 72 hr of treatment with DON, the undifferentiated cells had detached from the plate, whereas the differentiated cells remained intact. The results suggest that the GAG may be involved in cellular adhesion, particularly of the undifferentiated cells.

Histochemical studies of intercellular components of salivary gland tumors with special reference to glycosaminoglycan, laminin and vascular elements

In 41 salivary gland tumors, the characteristics of the intercellular components and vascular endothelial cells were surveyed by immunohistochemical staining for laminin and factor VIII-related antigen (VIII R:Ag), and by mucopolysaccharidase-digestion for glycosaminoglycan (GAG). In myxomatous areas of pleomorphic adenomas, small vessels (diameter 6.5 +/- 0.11 micron) were frequent and found to be negative or weakly positive by VIIIR:Ag staining although endothelial cells were clearly positive for VIIIR:Ag in capsule surrounding the tumor tissues. Alcian blue stainability was diminished by treatment with both Streptomyces hyaluronidase and chondroitinase. By laminin staining, a vascular pattern was clearly detected, but the majority of tumor cells were not stained. In adenomatous areas, the basement membrane-like linear laminin-staining reaction was observed to be weak and inconsistent around some tumor cell nests. However, in adenoid cystic carcinomas, laminin-positivity was much more intense than in other tumors such as pleomorphic adenoma, mucoepidermoid tumor and adenocarcinoma. In cylindromatous areas, the inner luminal surface in the pseudocysts was markedly positive for laminin, and there was weak positivity around tumor cell nests having a trabecular pattern. By immunoelectron microscopy, a juxtacellular network of replicated basal lamina of tumor cells which lined the inner surface of pseudocysts was positive for laminin. Alcian blue-positivity in the pseudocyst was abolished with heparitinase and chondroitinase, but not with hyaluronidase.

Changes in proteoglycan composition of F9 teratocarcinoma cells upon differentiation

Teratocarcinoma cells (F9) were induced to differentiate by retinoic acid and then labelled with [3H]-glucosamine and [35S]-sulphate. Proteoglycans were then isolated from the plasma membranes and the culture medium by mild, dissociative, non-shear-dependent techniques. The undifferentiated cells were devoid of hyaluronic acid and contained negligible quantities of heparan sulphate, dermatan sulphate and chondroitin sulphate. Upon differentiation, the cells synthesized large amounts of hyaluronic acid and there was a threefold increase in the amount of membrane-bound sulphated proteoglycans. The differentiated cells also synthesized a proteoglycan (PGM-2) which was shed completely into the medium. It consisted of a large protein core with covalently linked sugar chains which were sulphated and had an approximate molecular weight of 12000. These sugar chains consisted of glucosamine and galactose in a molar ratio of 1:1 and contained a small quantity of mannose. Upon differentiation of the cells the amount of this molecule increased by threefold. This molecule was distinct from other proteoglycans since it was resistant to degradation by heparanase, chondroitinases, hyaluronidase and neuraminidase, but could be degraded by keratanase. Structurally it was very similar to keratan sulphate, consisting of alternating residues of (-Gal-GlcNAc-) in chains of approximately 20 such disaccharide units.

Glycosaminoglycans and glycoproteins in bronchoalveolar lavage fluid from patients with pulmonary alveolar proteinosis

Bronchoalveolar lavage fluid from two cases of pulmonary alveolar proteinosis were analyzed for glycosaminoglycans and glycoproteins. The clinical courses of the two cases were entirely different. In one patient, signs and symptoms recurred despite repeated therapeutic bronchoalveolar lavages. In the other patient, three successive bronchoalveolar lavages brought about complete recovery. It was found that the bronchoalveolar lavage fluid from the former case contained various subtypes of glycosaminoglycans [hyaluronic acid, chondroitin sulfate A(C), dermatan sulfate, and heparan sulfate] and glycoprotein. On the other hand, the bronchoalveolar lavage fluid from the latter case contained glycoprotein, but no detectable amounts of glycosaminoglycans. There was only a slight qualitative difference in glycoprotein of bronchoalveolar lavage fluid between the two cases. The presence or absence of glycosaminoglycans in bronchoalveolar lavage fluid may be related to the prognosis of pulmonary alveolar proteinosis.

Purification and characterization of mucopolysaccharidase from an oral strain of Bacteroides sp

A mucopolysaccharidase in the cell extract of an oral strain of Bacteroides sp. was purified to homogeneity by ammonium sulfate precipitation, DEAE-cellulose column chromatography, gel filtration on Sephadex G-200, and isoelectric focusing. Specific activity increased 110-fold and recovery was 2%. The molecular weight was determined to be 89,000 by gel filtration, and the isoelectric point was 7.0. The optimum pH for the activity was 6.5. The enzyme was inactivated by heating at 60 degrees C for 5 min. The purified mucopolysaccharidase degraded hyaluronic acid more rapidly than chondroitin and chondroitin sulfate A and C. However, it had no activity against chondroitin sulfate B, heparin, and heparan sulfate. Since unsaturated disaccharides were derived from the enzyme substrate, this enzyme was considered to be a mucopolysaccharide lyase.

Isolation and characterization of two chondroitin lyases from Bacteroides thetaiotaomicron

Two chondroitin lyases were isolated from the colon anaerobe Bacteroides thetaiotaomicron. Both enzymes had similar molecular weights (104,000 and 108,000) and similar isoelectric points (8.0 and 7.9, respectively). Both enzymes were active against chondroitin sulfates A, B, and C and unsulfated polysaccharides, such as chondroitin and hyaluronic acid, although one of the enzymes was twice as active against chondroitin as the other enzyme. Both had similar Km values for chondroitin sulfates A and C (40 to 70 micrograms/ml) and for chondroitin (300 to 400 micrograms/ml). Neither enzyme could degrade the highly sulfated mucopolysaccharide heparin, but heparin was a potent inhibitor of the activity of both enzymes. Although enzymes I and II were similar in many respects, a comparison of peptides resulting from partial digestion with N-chlorosuccinimide or papain demonstrated that the two proteins are not related.

Glucuronic acid-containing glycopeptide from squid cartilage

A glycopeptide fraction containing glucuronic acid as a component sugar was extracted and purified from squid cartilage to give a single band migrating much slower than hyaluronic acid in cellulose acetate electrophoresis. The molecular weight of the glycopeptide was fairly large since its Kav value in Sephadex G-200 chromatography was 0.18; however, it was soluble in 66% ethanol. This glycopeptide contained glucuronic acid, glucosamine, galactosamine, galactose, and fucose. The total amino acid content was 1.87 mumol of amino acid per mg of the glycopeptide. Threonine, serine and proline represented 80% of the amino acids. Digestion with chondroitinase ABC or reaction with nitrous acid did not result in degradation of the glycopeptide; however, it was completely degraded by reaction with 0.5 M KOH at 37 degrees C. Two hexasaccharides were separated from the alkaline degradation products, and they both contained glucuronic acid, fucose, galactosamine, and reducing terminal glucosamine in the molar ratio, 2:1:2:1. These results indicated that the glycopeptide contains glucuronic acid-containing sugar chains that are distinct from any known glycosaminoglycan.

Sialomucin in Paget cells of extramammary Paget's disease

The cytoplasmic sialomucin in Paget cells of extramammary Paget's disease was examined by means of a battery of histochemical techniques. The staining methods used involved an electrolyte--Alcian Blue (pH 5.8), periodic acid--Schiff and azure A at selected pH levels. Methylation, saponification, borohydride reduction, acid hydrolysis, and digestion with diastase, neuraminidase (Vibrio cholerae) or chondroitinase ABC, were also employed. The cytoplasmic mucin was found to exhibit positive reaction for the above staining which were variously altered by the chemical modification procedures and diminished in intensity or abolished by digestion with neuraminidase. These results suggest that the cytoplasmic mucin is sialomucin without side-chain substituent in extramammary Paget's disease located in axillary or genital area, and with a substituent at C7 in the disease located in perianal area.

Extracellular matrix and the maintenance of the differentiated state: proteoglycans synthesized by replated chondrocytes and nonchondrocytes

It has been previously shown that undifferentiated stage 23 to 24 chick limb bud mesenchymal cells can be maintained in culture under conditions which promote chondrogenesis. As the chondrocytes mature in vitro, their proteoglycan synthesis progresses through a specific and reproducible biosynthetic program. By the eighth day of culture, the chondrocytes are making proteoglycans that are similar to proteoglycans isolated from adult animal tissues. Relative to the Day 8 proteoglycans, the proteoglycans synthesized by chick limb bud chondrocytes earlier in culture have a smaller monomer size, longer chondroitin sulfate chains, shorter keratan sulfate chains, a higher ratio of chondroitin-6-sulfate to chondroitin-4-sulfate, and a decreased ability to interact with hyaluronic acid. We have reported a procedure to remove the cells from Day 8 cultures and strip away most, if not all, of the extracellular matrix. In addition, the chondrocytes can be separated from the 40-50% nonchondrocytic cells normally found in Day 8 cultures, and the two cell populations replated separately. This report describes the analysis of the proteoglycans synthesized by replated cells; this analysis demonstrates quantitative and qualitative differences between chondrocyte and nonchondrocyte proteoglycans. The overall rate of proteoglycan synthesis is fourfold higher and the rate of synthesis of high buoyant density proteoglycans 30-fold higher for replated chondrocytes relative to nonchondrocytes. Qualitatively, more newly synthesized nonchondrocyte proteoglycans partition at lower buoyant density on CsCl equilibrium density gradients than do chondrocyte proteoglycans. Nonchondrocyte proteoglycans are of two major classes: One has a monomer size slightly smaller than that of Day 8 chondrocyte proteoglycan, but has much longer glycosaminoglycan chains. The other is considerably smaller than Day 8 chondrocyte proteoglycans, but has glycosaminoglycans of slightly larger size. In contrast, replated chondrocytes synthesize, even as soon as 4.5 hr after replating, proteoglycans that are identical to Day 8 chondrocyte proteoglycan in monomer size, in glycosaminoglycan chain size, in aggregability, and in the ratio of 6-sulfated to 4-sulfated chondroitin. Since denuding mature Day 8 chondrocytes of their extracellular matrix does not cause them to recapitulate their developmentally regulated program for the biosynthesis of proteoglycans, it is concluded that the quality of mature chondrocyte proteoglycan is not altered by the absence of extracellular matrix.

An improved automated periodate-resorcinol method for the determination of sialic acid

A periodate-resorcinol method for bound sialic acid using the Technicon Autoanalyzer II is presented. It has a sensitivity similar to the manual method, is linear between 5 and 65 nmol/ml, requires less than 0.2 ml of sample, and can be run at the rate of 70 samples/h. Little cross-reaction with common matrix and cell components was found. The method is compatible with many commonly used volatile and nonvolatile chromatographic buffers. The use of a bound sialic acid standard such as N-acetylneuraminyl lactose is recommended.

Biochemical defect of non-keratan-sulfate-excreting Morquio syndrome

Two children of second-cousin parents were found to have a very mild form of Morquio syndrome. The 14-year-old boy was 147 cm tall and had fine corneal deposits, a broad chest, dislocated hips, and flat feet. His 7-year-old sister had a broad chest but otherwise normal physical development. An abnormal lumbar spine was seen in radiographs of both children. Analysis of the urine from the affected children showed levels of acid mucopolysaccharides (AMPS) up to twice as high as that found in normal urine, but no evidence of keratosulfaturia. Most urinary AMPS was chondroitin-6-sulfate. Multiple assays of N-acetylgalactosamine-6-sulfate (GalNAc-6-SO4) sulfatase in leukocytes and cultured skin fibroblasts showed deficiency of this enzyme in the range found in the classical form of Morquio (Morquio A) syndrome. This report identifies an enzymatic defect in one form of non-keratan-sulfate-excreting Morquio (NKSE Morquio) syndrome and confirms the absence of keratosulfaturia in this mild form of Morquio disease.

Proteoglycans of rabbit cornea: labelling in organ culture and in vivo

Rabbit corneas maintained with radioactively-labelled precursors in organ culture for up to 42 hr produced labelled proteoglycans of the same kind as those that exist normally or that are produced by labelling in vivo. Whole corneas, including a narrow strip of sclera, were kept in culture in the presence of [3H]-glucosamine and [35S]-sulfate. The rate of incorporation of sulfate into extractable proteoglycans was linear over the time investigated, as was the rate of incorporation of glucosamine after a short lag. Three labelled proteoglycans were isolated and found to behave in ion-exchange chromatography and gel chromatography in the same way as they did in previous studies by chemical analysis. Their labelled glycosaminoglycans were primarily dermatan sulfate and keratan sulfate, with traces of hyaluronic acid and heparan sulfate. When labelled precursors were injected directly into the anterior chamber of rabbit eyes, the resulting labelled proteoglycans were similar to those obtained in organ culture. Both in vivo and during organ culture, the specific activity of hexosamine in the keratan sulfate proteoglycans was about one-half that in dermatan sulfate, probably because of different synthetic rates or different specific activities of immediate precursors.

Analysis of cartilage differentiation from skeletal muscle grown on bone matrix. III. Environmental regulation of glycosaminoglycan and proteoglycan synthesis

The ability of numerous nutritional and topographic factors to influence differentiation of embryonic mesenchyme has given rise to several theories which attempt to explain the development of muscle and cartilage from these similar-appearing cells. Some theories are challenged by the observation that a substratum of demineralized bone is capable of supporting the transformation of skeletal muscle into cartilage in vitro and that the potential to form cartilage still resides within cloned myoblasts and fibroblasts of skeletal muscle. In the present study, culture media CMRL-1066, minimal essential medium (MEM), and F-12 provide varied nutritional environments and are tested for their ability to support the morphological and biochemical transformation of skeletal muscle into cartilage. Morphologically, CMRL-1066 reproducibly supports hyaline cartilage formation, whereas MEM does so in only one out of three explants onto demineralized bone, and F-12 is incapable of supporting formation of a hyaline matrix. Biochemically, each medium is sufficient to elicit synthesis of cartilage-like patterns of sulfated glycosaminoglycans and proteoglycan monomer. Synthesis of hyaluronic acid (HA) initially increases in explants grown in CMRL-1066, but decreases prior to chondrogenesis. MEM elicits a similar increase in HA synthesis, but the subsequent decrease is not as rapid. In F-12, synthesis remains depressed throughout the experiment. The data show that increases in HA synthesis occur concurrent with the appearance of fibroblast-like cells, which normally precede chondroblasts. Decreases in HA synthesis correlate well with the onset of chondrogenesis. Explants grown in CMRL-1066 reproducibly from cartilage and synthesize the greatest amounts of proteoglycan aggregate. Those grown in MEM form cartilage infrequently, synthesize reduced amounts of proteoglycan aggregate-like material, and contain greater amounts of HA, of low molecular weight. The data demonstrate that chondrogenesis can be subtly regulated by environmental factors, and such factors regulate both the morphological and biochemical expression of the phenotype through HA synthesis.

Digestion of proteoglycan by Bacteroides thetaiotaomicron

It has been shown previously that Bacteroides thetaiotaomicron, a human colonic anaerobe, can utilize the tissue mucopolysaccharide chondroitin sulfate as a source of carbon and energy and that the enzymes involved in this utilization are all cell associated (A. A. Salyers and M. B. O'Brien, J. Bacteriol. 143:772-780, 1980). Since chondroitin sulfate does not generally occur in isolated form in tissue, but rather is bound covalently in proteoglycan, we investigated the extent to which chondroitin sulfate which is bound in such a sterically hindered complex can be utilized by intact bacteria. Intact cells of B. thetaiotaomicron were able to digest chondroitin sulfate in proteoglycan, although at a slightly slower rate than free chondroitin sulfate. Prior digestion of proteoglycan with trypsin to produce small fragments of protein with several chondroitin sulfate chains attached did not increase the rate at which the bound chondroitin sulfate was digested. Accordingly, the slower rate of digestion was probably due to attachment of chondroitin sulfate chains to the protein backbone rather than to steric hindrance by other components of the proteoglycan. When proteoglycan which had been incubated with intact bacteria was treated with sodium borohydride to release the undigested fragments of chondroitin sulfate from the protein backbone, the size and composition of the fragments indicated that intact bacteria were able to digest all but three monosaccharides of the chondroitin sulfate chains. Thus, despite steric hindrance due to attachment of the chondroitin sulfate chains to the protein backbone, digestion of bound chondroitin sulfate by intact bacteria was nearly complete.

The effect of chondroitin sulfate molecular weight and degree of sulfation on the activity of a sulfotransferase from chicken embryo epiphyseal cartilages

The transfer of [35S] sulfate from [35S]PAPS, by means of PAPS: chondroitin sulfate sulfotransferase, to various chondroitin sulfates, with different degrees of sulfation and molecular weights is reported. Analyses by digestion with chondroitin AC and specific 4- or 6-sulfatases indicate that the sulfation occurs only in position 6 of the non-sulfated N-acetyl galactosamine moiety. The 50-70% desulfated chondroitin 4/6-sulfates are two times better sulfate acceptors than totally desulfated chondroitin, and the affinity of the sulfotransferase increases markedly from the octa-to the deca-saccharide. These results suggest that sulfation increases sharply only after the growing polysaccharide contains about 10 sugar residues, in the early stages of polymerization, and that the sulfation of chondroitin sulfate may be a process in which the addition of some sulfate groups facilitates further sulfation.

Isolation of three species of proteoglycan synthesized by cloned bone cells

Three proteoglycan fractions have been isolated from clonal populations of osteoblast-like cells derived from fetal rat calvaria. One of these is secreted into the culture medium, is of apparent Mr 350 000, and has a glycosaminoglycan (GAG) composition of 77% chondroitin sulfate (CS) and 20% dermatan sulfate (DS). The remaining two proteoglycan fractions are associated with the cell layer. One of these has an apparent molecular weight of approximately 250 000 and a GAG composition of 54% CS and 40% DS. Both this species and the secreted proteoglycan have GAG chains of Mr 25 000. The other cell-associated proteoglycan contains heparan sulfate (HS), is solubilized by detergents, and appears to be contaminated with a CS proteoglycan. This HS-containing species may be similar to plasma membrane proteoglycans that have been isolated from several other cell types. Rat calvarial clones also synthesize hyaluronic acid and a number of glycoproteins.

The structural characterization of proteoglycans of cultured aortic smooth muscle cells and arterial wall of the pig

Aortic proteoglycans, from the growth medium of cultured smooth muscle cells and from sequential associative and dissociative extracts of the tissue of origin, the pig aorta, were isolated and purified by precipitation with cetylpiridinium chloride. After isopycnic CsCl gradient centrifugation under associative conditions 94% of the cell-secreted proteoglycans were recuperated in the bottom one fifth (rho av = 1.62 g/ml) fraction. In contrast 80% of the tissue proteoglycans of both extracts, fractionated into two fractions: the bottom one fifth (rho av = 1.60 g/ml) fraction and three fifths (rho av = 1.42 g/ml) fraction. Fractionated tissue proteoglycans were composed predominantly of chondroitin sulfate-dermatan sulfate (83-90%) with lower proportions of heparan sulfate (5-11%) and hyaluronic acid (3-6%) whilst cell-secreted proteoglycans showed a similar glycosaminoglycan composition but with a higher proportion of hyaluronic acid (11-13%). Sepharose 2B and C1-2B chromatography of tissue proteoglycans of high buoyant density showed the presence of only subunit proteoglycans whilst those of intermediate density contained a complex species, partially dissociable in 4 M guanidinium chloride, along with Kav 0.50 subunit species. The latter was also observed for cell-secreted proteoglycans although obtained at high buoyant density. The cell-secreted subunit proteoglycans became separated into two distinct populations when chromatographed on Sepharose 4B and C1-4B, half of which eluted in the column Vo and the rest at a Kav of 0.34. The majority of subunit macromolecules eluted at the Vo fractions of Sepharose 6B and C1-6B columns. Unlike the major species of cartilage proteoglycans, only approx. 20% of purified arterial proteoglycans formed complexes. This proportion could be increased by only 4-7% by interaction, of a mixture of subunit cell-secreted and tissue-extracted proteoglycans, with hyaluronic acid. These results suggest that proteoglycans secreted by cultured aortic smooth muscle cells and present in the aortic tissue possess certain similar physicochemical properties and are present in the form of complex and several subunit species.

Malignant papillary cystadenoma lymphomatosum. Light and electron microscopic study

A case of malignant papillary cystadenoma lymphomatosum was investigated by light and electron microscopy. Histologically, the tumor consisted mainly of a characteristic papillary cystadenoma lymphomatosum, but the feature of epithelial components varied greatly in separate portions of the tissue; papillary adenoma-, tubular adenocarcinoma-, acinic cell tumor- or oncocytoma-like features were observed, the tumor cells showing "atypia" in major components. Numerous intracytoplasmic inclusions were found in many oncocytic cells arranged in acinar structure, and stained with PAS, AZAN or Alcian blue. Electron microscopically, large numbers of very large, swollen and closely packed mitochondria were observed in almost all the tumor cells. The intraplasmic inclusions were composed mainly of a long dense body enclosed by a single unit membrane, and the contents constituted bundles of fine filament running parallel to the longer axis. The inclusions were often observed to unite with lysosomes and to co-exist with secretory granules in the cytoplasm.

The site of sulfated glycoprotein biosynthesis in rat gastric mucosa

The site of the synthesis of the sulfated glycoproteins in rat gastric mucosa using organ culture system has been studied. About 98% of the 35S radioactivity associated with the glycoproteins was found in corpus region. The sulfated glycoproteins were synthesized mainly in corpus, poorly in antrum and none in forestomach. The synthesized sulfated glycoproteins were heterogeneous by equilibrium centrifugation in CsCl density gradients. The 35S-labeled oligosaccharides released from the glycoproteins under alkaline condition were composed of 4-8 sugar residues.

A simple method for the quantitation of glycuronic acid-containing glycosaminoglycans with mucopolysaccharidases

A simple method for the quantitative determination of glycuronic acid-containing glycosaminoglycans (UA-GAG) is described. Sample solutions of glycosaminoglycans were digested with chondroitinase AC, chondroitinase C, chondroitinase B, heparitinases, and Streptomyces hyaluronidase, respectively, and the absorbance was read at 232 nm after digestion. The contents of 4-O-sulfated N-acetylgalactosaminyl beta (1 leads to 4)D-glucosiduronyl units (Ch-4S), 6-O-sulfated N-acetylgalactosaminyl beta (1 leads to 4)D-glucosiduronyl units (Ch-6S) plus N-acetylgalactosaminyl beta (1 leads to 4)D-glucosiduronyl units (Ch-OS), 4-O-sulfated N-acetylgalactosaminyl beta (1 leads to 4)L-idosiduronyl units (D-4S) plus N-acetylgalactosaminyl beta (1 leads to 4)L-idosiduronyl units (D-OS), heparan sulfate, and hyaluronic acid in the sample solutions were calculated from the absorbance with reference to that of the digestion products of known amounts of standard UA-GAG. The analytical data obtained with the mixtures of authentic UA-GAG were in close agreement with the theoretical values. Application of this procedure to the urinary GAG fractions from orthopedic patients gave satisfactory results.

The glycosaminoglycans of normal and hyperplastic prostate

A study has been made of the glycosaminoglycans (GAG) of the fetus, normal adult, and benign hyperplastic prostate. In the adult normal prostate dermatan sulphate (DS) is the predominant GAG. The central zone has a slightly higher chondroitin sulphate (Ch AC) content than the peripheral zone. Fetal prostates (22-27 weeks gestation) contain no heparan sulphate (HS). Benign prostatic hyperplasia (BPH) has an increased content of Ch AC. On separation of BPH stroma and epithelium, the epithelial fraction contains only Ch AC and DS. HS and hyaluronic acid (HA) are confined to the prostatic stroma.

Glycosaminoglycans in embryonic mouse teeth and the dissociated dental constituents

The nature, amounts and distribution of glycosaminoglycans (GAG) before and during odontoblast terminal differentiation were studied. GAG have been isolated from intact mouse tooth germs and from dissociated dental epithelia and dental papillae after labeling with [3H]glucosamine or 35SO2-(4) asd precursor. The kinds and relative amounts of 3H-labeled GAG were analyzed by chromatography on a DEAE-cellulose column and cellulose thin-layer sheets. The amounts of individual GAG relative to total GAG were determined from the elution profiles, whereas their nature was identified by the selective removal of chromatographic peaks after enzymatic or chemical degradation. We found hyaluronate and probably a minute quantity of heparan sulfate in the dental epithelium, while hyaluronate, heparan sulfate, and chondroitin sulfate were the main types of GAG in the dental papilla. The chondroitin sulfate recovered was further fractionated by cellulose thin-layer chromatography into two isomers, namely chondroitin-2-sulfate (the major component) and chondroitin-6-sulfate. Changes in the elution profile from DEAE-cellulose chromatography of tooth GAG extracted from different developmental stages suggest that modifications of GAG occur during odontogenesis. Alcian blue staining localized large amounts of hyaluronate and sulfated GAG along the epithelio-mesenchymal junction. Tissue specificity and changing patterns of GAG were demonstrated during odontogenesis.

The effect of digestion with keratanase (Pseudomonas sp.) on certain histochemical reactions for glycosaminoglycans in cartilaginous and corneal tissues

The effect of digestion with keratanase (Pseudomonas sp.) on the Alcian Blue (AB) pH 1.0, pH 2.5, Aldehyde Fuchsin, high iron diamine, low iron diamine and dialysed iron-ferrocyanide reactions has been tested in the costal and ear cartilage tissues of the rabbit and corneal tissues of the rat and rabbit. The effect of digestion with chondroitinases ABC and AC on the same reactions was examined in the same tissues for comparison. Digestion with keratanase diminished the intensity of all the reactions in the cartilage tissues to a variable extent; however, the diminutions in intensity of the reactions appeared to be less marked as compared with those following digestion with two chondroitinases. In the corneal stroma, all the reactions were markedly reduced in intensity following digestion with keratanase. In contrast, these reactions were only slightly or moderately diminished in intensity by digestion with the two chondroitinases. As glycosamino-glycans are known to be present in cartilage and corneal tissues and the substrate specificities of the three enzymes used are now well established, the present results are consistent with the concept that keratanase specifically degrades and releases keratan sulphates involved in the tissues.

Acidic glycosaminoglycan, lipid and water contents in human coronary arterial branches

The acidic glycosaminoglycans (AGAG) of the human coronary arterial tree (the main left and right branches and their distal portions) were analyzed by enzymatic methods employing chondroitinases, hyaluronidase and heparitinase. The AGAG content of human coronary arteries was highest in the left branch, intermediate in the right branch and lowest in the distal portions. Some compositional differences in AGAG were found in these three parts. The amount of AGAG in the coronary arterial tree decreased with increasing severity of atherosclerosis. The main AGAG were heparan sulfate (HS) and chondroitin 6-sulfate (C-6S), constituting 33-38% and 24-36% of the total AGAG, respectively. Dermatan sulfate (DS) and chondroitin 4-sulfate (C-4S) each comprised 1/5-1/10 of the total AGAG. Hyaluronic acid (HA) and oversulfated DS comprised smaller proportions of the total AGAG. A small amount of heparin was occasionally detected in the coronary arterial tree, particularly in the distal portions. The lipid content of the main branches was increased in mildly atherosclerotic parts but diminished in severely affected parts. The water content was relatively higher in the main branches and decreased with severity of atherosclerosis. A possible function of these AGAG in atherosclerosis is discussed with respect to the compositional changes.

The effect of hypoxia on the synthesis of collagen and glycosaminoglycans by cultured pig aortic endothelium

Porcine aortic endothelium cultured at 20% oxygen concentration synthesizes collagen and three of its marker enzymes - proline and lysine hydroxylases and lysine oxidase, the cross-link enzyme. It also synthesizes and secretes hyaluronic acid, dermatan sulphate, possibly heparan sulphate, large amounts of chondroitin 4-sulphate and smaller amounts of chondroitin 6-sulphate. Growth of these cells for 24 h in 0%, or 2% oxygen results in little change in cell numbers or cell protein but a fall in collagen synthesis and in proline and lysine hydroxylases, but a rise in lysine oxidase. There is a considerable increase in synthesis and secretion of all the glycosaminoglycans found. The cell lipids appear qualitatively unchanged. Apart from increased lysosomes seen at 0% oxygen, no ultrastructural changes appear to occur. These findings illustrate the lability of the endothelial response to oxygen lack.

Separation and characterization of chondroitin 6-sulfotransferase and chondroitin 4-sulfotransferase from chick embryo cartilage

Two distinct sulfotransferases (chondroitin 6-sulfotransferase and chondroitin 4-sulfotransferase), which catalyzed transfer of sulfate to position 6 and position 4 of acetylgalactosamine residues of chondroitin, were extracted from epiphyseal cartilage of 14-day-old chick embryos and separated by gel chromatography on Sephacryl S-200 in the presence of 3 M guanidine-HCl. When the enzyme solutions containing 3 M guanidine-HCl were dialyzed against 0.02 M Tris-HCl, pH 7.2, containing 10% glycerol, chondroitin 4-sulfotransferase became almost insoluble, whereas chondroitin 6-sulfotransferase remained soluble. Endogenous acceptors for sulfate transfer were completely removed from both enzyme preparations. Addition of basic proteins and polyamines as well as Mn2+ to the incubation medium caused a stimulation of both sulfotransferases; the stimulation of chondroitin 6-sulfotransferase with these cations was higher than that of chondroitin 4-sulfotransferase. The Km values for 3'-phosphoadenylyl sulfate of both enzymes were much smaller in the presence of protamine or spermine than in the presence of Mn2+. The two sulfotransferases differed in the requirement for sulfhydryl compounds; in the absence of sulfhydryl compounds, the activity of chondroitin 4-sulfotransferase was very low, whereas the activity of chondroitin 6-sulfotransferase was essentially unaffected. These observations indicate that at least two sulfotransferases are involved in the biosynthesis of chondroitin sulfate, and suggest that the production of the isomers of chondroitin sulfate in chondrocytes is affected by various factors such as the intracellular concentration of sulfhydryl compounds and basic substances.

Glycosaminoglycans produced by human synovial cell cultures

Human synovial cells in culture are known to synthesize hyaluronic acid, but the production of sulfated glycosaminoglycans (GAG) has received less attention. Using 14C-glucosamine as a precursor, GAG content was studied in the medium, trypsin-solubilized pericellular layer, and cell residue fraction of cultured synovial cells derived from the synovial membranes of nonrheumatoid and rheumatoid joints. Over 90% of the total non-dialyzable counts appeared in the culture medium, for the most part in hyaluronic acid. The remaining nondialyzable counts were cell-associated, almost equally divided between the pericellular layer and cell residues. In these fractions, only part of the counts were in GAG susceptible to testicular hyaluronidase digestion, and GAG were significantly lower in the cell residue of the rheumatoid synovial cells compared to the nonrheumatoid cells. Analysis of the chondroitinase ABC and AC digestion products of these GAG indicated the presence of chondroitin-4 and -6 sulfates, and dermatan sulfate, but not heparan sulfate. Similar findings with respect to the identity of the GAG in nonrheumatoid and rheumatoid synovial cell culture media were obtained with 35SO4 as a precursor.