Microanalysis of glycosaminoglycans

The Anticancer Role of Capsaicin in Experimentallyinduced Lung Carcinogenesis

OBJECTIVES

Capsaicin (CAP) is the chief pungent principle found in the hot red peppers and the chili peppers that have long been used as spices, food additives and drugs. This study investigated the anticancer potential of CAP through its ability to modify extracellular matrix components and proteases during mice lung carcinogenesis.

METHODS

Swiss albino mice were treated with benzo(a) pyrene (50 mg/kg body weight dissolved in olive oil) orally twice a week for four successive weeks to induce lung cancer at the end of 14(th) week. CAP was administrated (10 mg/kg body weight dissolved in olive oil) intraperitoneally. Extracellular matrix components were assayed; Masson's trichome staining of lung tissues was performed. Western blot analyses of matrix metalloproteases 2 and 9 were also carried out.

RESULTS

In comparison with the control animals, animals in which benzo(a)pyrene had induced lung cancer showed significant increases in extracellular matrix components such as collagen (hydroxy proline), elastin, uronic acid and hexosamine and in glycosaminoglycans such as hyaluronate, chondroitin sulfate, keratan sulfate and dermatan sulfate. The above alterations in extracellular matrix components were effectively counteracted in benzo(a)pyrene along with CAP supplemented animals when compared to benzo(a) pyrene alone supplemented animals. The results of Masson's trichome staining for collagen and of, immunoblotting analyses of matrix metalloproteases 2 and 9 further supported the biochemical findings.

CONCLUSION

The apparent potential of CAP in modulating extracellular matrix components and proteases suggests that CAP plays a chemomodulatory and anti- cancer role working against experimentally induced lung carcinogenesis.

Efficacy of Annona squamosa L in the synthesis of glycosaminoglycans and collagen during wound repair in streptozotocin induced diabetic rats

The aim of this work was to find out the effects of Annona squamosa on the formation of glycosaminoglycans and collagen during wound healing in normal and diabetic rats. Diabetes induced rats were segregated into 4 groups, each containing six animals. Groups I and III served as the normal and diabetic control while groups II and IV served as normal and diabetic treated. The animals were treated with 200 μL of Annona squamosa extract topically. The granulation tissues formed were removed on the 8th day and the amount of glycosaminoglycans (GAGs) and collagen formed was evaluated by sequential extraction and SDSPAGE, respectively. Histological evaluation was also carried out using Masson's trichrome stain. In vitro wound healing efficacy of A. squamosa in human dermal fibroblast culture (HDF) was also carried out. The fibroblasts treated with varying concentrations of A. squamosa were examined for proliferation and closure of the wound area and photographed. A. squamosa increased cellular proliferation in HDF culture. The granulation tissues of treated wounds showed increased levels of glycosaminoglycans (P < 0.05) and collagen which were also confirmed by histopathology. The results strongly substantiate the beneficial effects of A. squamosa on the formation of glycosaminoglycans and collagen during wound healing.

Effect of Semecarpus anacardium nut extract on ECM and proteases in mammary carcinoma rats

The early stages of invasion are characterized by the extracellular proteolysis and the accumulation of specialized extracellular matrix (ECM) scaffold, that are responsible for the development of vascular bed, endothelial cell proliferation and invasion of tumour cells. The ground substance of provisional matrix consists of collagen, elastin, glycoaminoglycans and proteoglycans that facilitate the interaction of tumour cells with the host environment. In the present work, we have studied the influence of Semecarpus anacardium nut milk extract on localized differentials of ECM component and proteases involved in matrix metabolism of tumour tissue. Mammary carcinoma was induced in Sprague Dawley rats with 7,12, dimethyl benz(a)anthracene and treated with S. anacardium nut milk extract administered orally for 14 days. The altered amount of ECM components in tumour tissues was almost reverted back to normal level in the drug treated animals. The activities of reported proteases and glycohydrolases were also decreased on treatment with S. anacardium nut milk extract indicating decreased turnover of the matrix. Also, the factors associated with the matrix turnover and expression of MMP-1, MMP-2, MMP-3, TIMP-1 and TIMP-2 were restored back to near normal values. The stabilization of the ECM with the decreased activity of proteases might inhibit the epithelial-endothelial interaction and tumour cell migration thus, preventing the adjacent invasion and tumour growth and might be regarded as antineoplastic agent which demands further studies.

Influence of Aloe vera on the glycosaminoglycans in the matrix of healing dermal wounds in rats

The influence of Aloe vera (L.) Burman f. on the glycosaminoglycan (GAG) components of the matrix in a healing wound was studied. Wound healing is a dynamic and complex sequence of events of which the major one is the synthesis of extracellular matrix components. The early stage of wound healing is characterized by the laying down of a provisional matrix, which is then followed by the formation of granulation tissue and synthesis of collagen and elastin. The provisional matrix or the ground substance consists of GAGs and proteoglycans (PGs), which are protein GAG conjugates. In the present work, we have studied the influence of Aloe vera on the content of GAG and its types in the granulation tissue of healing wounds. We have also reported the levels of a few enzymes involved in matrix metabolism. The amount of ground substance synthesized was found to be higher in the treated wounds, and in particular, hyaluronic acid and dermatan sulphate levels were increased. The levels of the reported glycohydrolases were elevated on treatment with Aloe vera, indicating increased turnover of the matrix. Both topical and oral treatments with Aloe vera were found to have a positive influence on the synthesis of GAGs and thereby beneficially modulate wound healing.

Proteoglycan expression by human trabecular meshworks

PURPOSE

Proteoglycans may serve important roles in trabecular meshwork structure or function. Detailed molecular characterization and identification of specific trabecular proteoglycan core proteins has been limited.

METHODS

Radiolabeled proteoglycans were extracted from cultured human trabecular meshworks and subjected to ion exchange and molecular sieve chromatography. Peaks were subjected to glycosaminoglycan content analysis. Reverse transcription with polymerase chain reaction was used to identify trabecular mRNAs of several common proteoglycan core proteins. Western immunoblots of trabecular extracts were also utilized to identify these proteoglycan core proteins.

RESULTS

The proteoglycans elute from ion exchange columns at high salt and molecular sieve column profiles, and they exhibit broad peaks typical of the proteoglycan microheterogeneity seen in other tissues. The four common glycosaminoglycan side-chains were identified on these proteoglycans. Trabecular cells in organ or cell culture contain mRNAs coding for decorin, biglycan, versican, perlecan and a basement membrane glycoprotein, SPARC. Syndecan-1 transcripts were present at very low levels, while aggrecan transcripts were not detectable. Decorin, biglycan, versican and perlecan core proteins were also identified by immunoblots of trabecular cell extracts.

CONCLUSIONS

Several common proteoglycans are expressed by trabecular cells in organ explant or cell culture. Their general characteristics are not unlike those found in other tissues. These proteoglycans may serve important functions in the trabecular outflow pathway.

The glycosaminoglycans in cultures of stimulated rat peritoneal macrophages. 2. Gel chromatographic studies and the behaviour of heparan sulfate

The molecular weight distribution of pMP-derived glycosaminoglycans (GAG), i.e. non-sulfated GAG, chondroitin sulfate (CS), and heparin sulfate (HS)-like material was determined. The peritoneal macrophages (pMP) were harvested from rats normal or stimulated by i.p. injection of thioglycolate, carrageenan or BCG, and maintained in culture. The GAG of cell layer and medium were isolated separately after labeling with 35S-sulfate and 3H-acetate. Treatment with nitrous acid served to remove HS-like material. Labeling with 3H-acetate served to detect synthesis of the high m. w. hyaluronic acid (HA). Gel chromatic separation was done using Sephadex G-200 columns. The maximal size of 35S-labeled GAG, especially HS (36 kDa), was reduced in cultural medium and cell layer after stimulation in vivo. Reduction was most pronounced after application of carrageenan followed by thioglycolate and BCG/LPS stimulation. The extracellular GAG of BCG-stimulated pMP were smallest, probably due to degradation. Heparan sulfate-like material made up a larger proportion in monolayer and medium, comprising the total m.w. range up to 36 kDa. The GAG sensitive to nitrous acid were maximal in cultures of carrageenan-stimulated pMP and minimal in those of thioglycolate-stimulated pMP. This type of HS was sensitive to hyaluronidase, too. Any synthesis of high molecular hyaluronic acid was not found in normal or stimulated rat pMP. Therefore MP-associated HA must be adsorbed from other sources or synthesized by early forms of macrophages.

The glycosaminoglycans in cultures of stimulated rat peritoneal macrophages. 1. Pattern and biosynthesis of glycosaminoglycans

Macrophages produce and secrete proteoglycans. They are involved in inflammation and may contribute to the glycosaminoglycans (GAG) and proteoglycans (PG) characteristic of the inflamed area. This possible contribution was studied with rat peritoneal macrophages (pMP) in vitro. The total amount, composition, and neosynthesis of the GAG (as the main constituents of PG) were determined in cultured pMP of normal rats or rats pretreated with casein, BCG, thioglycolate or carrageenan. Partly the stimulated pMP were further activated with LPS or PMA. The rat pMP contained non-sulfated GAG, chondroitin sulfate and heparan sulfate but no dermatan sulfate. The GAG amount per cell increased with duration of the culture. In most cases the final level of GAG roughly corresponded to that of 12 micrograms hexuronic acid per 10(6) cells. It was lower after BCG stimulation (25%) and higher in pMP stimulated by both casein and LPS (200%). The average percentage of the GAG secreted (40%) was enhanced with pMP stimulated by carrageenan (87%) or casein plus LPS (69%). The pattern of the GAG in cultural media, cell coat and cells differed markedly. Thus the cell coat contained a higher amount of heparan sulfate. Differences due to stimulation were mainly seen in the reduced sulfation of the CS-proteoglycan secreted (casein-, BCG-pMP). According to studies on the incorporation of 35S-sulfate and 3H-acetate the GAG of the cell coat are less labeled and more conservative. The bulk of newly synthesized GAG/PG is secreted. This secretion appears an important property of macrophages the cause of which is speculative.

The glycosaminoglycan metabolism of chondrocyte monolayer cultures under normal and pathological conditions. A methodic study

Chondrocyte cultures may serve as a model in investigating changes of the cartilage metabolism. Adherent chondrocytes in vitro maintain polygonal morphology at high cell density in the primary and secondary culture. Collagen type II is only clearly detected in multilayered or nodular areas. The differentiation of the chondrocytes is also indicated by a low HA concentration of the cultural medium. It depends on high cell density, a low number of subcultures and their duration. However, the medium GAG of chondrocyte cultures does not exactly mirror the state of cell differentiation but can partly be used to check it. Subcultures of chondrocytes on small cover slides (minicultures) are used to determine proteoglycan synthesis and degradation for 48 h each. Both synthesis and degradation of cell-associated GAG or proteoglycans, resp., follow similar complex kinetics. The half lives of sulfated GAG or proteoglycans are initially 10 h (T-1 for O-6 h of chase), later 39 h or 95 h (T-2 for 6-48 h of chase). Conditioned medium of casein-elicited rat peritoneal macrophages reduce the sulfate incorporation into chondrocyte proteoglycans and their degradation rates increase. In the additional presence of E. coli endotoxin (0.5 microgram/ml) the synthesis of proteoglycans is only little affected; the degradation rate is stronger increased. To peritoneal macrophages of rats manifold pretreated with BCG and perhaps desensitized, LPS is added in vitro. Conditioned medium of these MP does not affect the chondrocyte proteoglycan synthesis but enhances the degradation rates in a concentration-dependent manner. Thus it can be demonstrated that chondrocyte monolayer miniscale cultures may serve to elucidate changes in the proteoglycan synthesis and different degradative steps.

Glycosaminoglycans in cortical autopsy samples from Alzheimer brain

Each of the known classes of mammalian glycosaminoglycans, with the exception of keratan sulphate, was found in cerebral cortex samples from patients with Alzheimer-type dementia and age-matched controls. These molecules were quantitated, after electrophoresis and staining with Alcian Blue dye, by scanning densitometry. No significant differences were found between the mean levels of each of the above glycosaminoglycans in frontal cortex from patients with dementia compared with controls. An increase (26%; p less than 0.05) in the mean level of hyaluronate, but not of other glycosaminoglycans, was found in temporal cortex samples. On the other hand, the uronic acid content of hyaluronate degradation products following Streptomyces hyaluronidase treatment of brain glycosaminoglycans did not reveal any statistically significant changes in Alzheimer's disease. HPLC of disaccharide products from Arthrobacter chondroitinase AC digests did not reveal any significant changes in sulphate substitution of chondroitin sulphate in Alzheimer brain.

Developmental and age-related changes in rat brain glycosaminoglycans

The quantities of each major class of glycosaminoglycan were determined in rat cerebrum from postnatal day 5 to 30 months of age. Chondroitin sulphate, dermatan sulphate, heparan sulphate, heparin, and hyaluronate were found, but no keratan sulphate was detected. Large and rapid changes in glycosaminoglycan content were observed during the period of brain maturation, and thereafter relatively steady levels were maintained until after the age of 12 months. The most remarkable change in the aged rat cerebrum was the ratio by weight of hyaluronate to chondroitin sulphate, which was approximately 1:1 from postnatal day 10 to 18 months but increased to 2.6:1 by the age of 30 months. In immature rats, the proportion of nonsulphated and 6-sulphated disaccharides derived from chondroitinase AC digests of brain glycosaminoglycans was much greater than in adults. In mature rats, chondroitin sulphate was composed almost entirely of 4-sulphated disaccharide subunits. The possibility that these changes could affect the permeability properties of the cerebral extracellular space and ionic equilibria in the brain is discussed.

The glycosaminoglycans of the macrophage-like cell line PeMa in suspension and monolayer culture

The macrophage-like cell line PeMa was cultured both in suspension and in monolayer for biochemical studies. It is concluded that adherent PeMa when compared with suspended cells --contain three times more GAG in medium, cell coat, and cells: --contain higher amounts of HS and CS in the cell coat; --release a minor proportion of sulfated GAG (HS) into the medium; --contain in their medium longer chains of HS and CS/DS; --contain in cell coat and cells higher amounts of a family of HS chains with high to low molecular weights. In suspension and monolayer cultures, the cell coat GAG were scarcely labelled; they are likely to be produced at another time and to turn over slowly. It is suggested that this study will be helpful to understand the behaviour of macrophages and other cells.

Localization of glycosaminoglycans in human and canine menisci and their attachments

The semilunar meniscal body, horns and peripheral attachment were dissected from human and canine knee joints. The concentrations of hyaluronate, chondroitin sulfate, dermatan sulfate and keratan sulfate differed markedly among the tissues. The meniscal body was fibrocartilaginous but showed marked histological microheterogeneity with hyalinized areas intermixed with fibrous areas and contained mostly chondroitin sulfate and keratan sulfate. On the other hand, the fibrous peripheral attachment contained mostly dermatan sulfate and hyaluronate and almost no keratan sulfate and the ligamentous horns contained mostly dermatan sulfate and chondroitin sulfate. Human menisci contained more dermatan sulfate and less chondroitin sulfate than did canine menisci. From morphometric measurements of canine menisci, an estimate was made of the amount of peripheral tissue which had been included with the body when dissections were based on gross appearance and how much this might influence analysis of the composition. This local variation emphasises the need for careful anatomical description in studies of the composition of menisci, but suggests that previously noted changes in the composition of menisci in osteoarthritis result from the disease, not dissection differences.

The effect of tensional load on isolated embryonic chick tendons in organ culture

Digital flexor tendons isolated from 17-18 day embryonic chickens were cultured intact, either on steel mesh grids, or in an apparatus designed to apply a mechanical load to the tissue. Tendons cultured without an applied load continued to synthesize protein and glycosaminoglycans throughout a 7-day period, but DNA synthesis decreased during this time. Increases in both protein and DNA synthesis were observed in tendons experimentally loaded for 48-72 h. Glycosaminoglycan production by tendons isolated from 17-day embryos was also increased in loaded tendons, sulfated GAG being increased more than hyaluronic acid. The same loading regime applied to tendons from 18-day embryos produced a smaller, yet significant increase in sulfated glycosaminoglycans but hyaluronate production was reduced. These investigations demonstrate that embryonic chicken tendons can be maintained in a viable state in organ culture and may provide a useful model for studies of the effects of mechanical forces on the synthetic capability and structure of connective tissue cells.

Age-related changes in the cerebrospinal fluid outflow glycosaminoglycans

The glycosaminoglycan distribution patterns of the cerebrospinal fluid (CSF) outflow pathway, dura mater and cerebral cortex of young New Zealand red rabbits and 1-, 3- and 12-week-old C-57 mice were identified by analyses of the glycosaminoglycan moieties and by the use of zone electrophoresis. The glycosaminoglycans were identified by specific degradation procedures, i.e., hyaluronate lyase, chondroitin ABC lyase, endo-beta-D-galactosidase and nitrous acid treatment. The CSF outflow pathway and dura mater glycosaminoglycan components were primarily hyaluronic acid and chondroitin sulfate-dermatan sulfate, whereas the cerebral cortex glycosaminoglycan components were hyaluronic acid, chondroitin sulfate-dermatan sulfate, keratan sulfate and heparan sulfate. The glycosaminoglycan components of the dura mater and cerebral cortex decreased and those of the CSF outflow pathway increased as a function of age. These results demonstrate the feasibility of analyses of the CSF outflow pathway glycosaminoglycan components and suggest that topographical changes in the glycosaminoglycan distribution profiles may contribute to the pattern of cerebrospinal fluid outflow.

Chromatography on DEAE-cellulose microcolumns: a quantitative method for the fractionation of small quantities of glycosaminoglycans

A simple, sensitive, and efficient method is described for qualitative and quantitative determination of glycosaminoglycans (GAG) synthesized by embryonic mouse teeth. After release from proteoglycan aggregates by enzymatic treatment, a mixture of different GAG was absorbed on a DEAE-cellulose microcolumn (Whatman DE-52 microgranular) at low salt concentration. The different types of GAG were eluted by stepwise increases in the concentration of NaCl. Glycopeptides, which generally contaminate the extract, can be completely removed prior to the elution of GAG. The eluate fractions were analyzed by rechromatography on the same column, using gradient elution. The stepwise elution is suitable for analysis as well as preparation of labeled GAG, the supply of which is limited in amount. The scale of chromatography can easily be stepped up. Quantitative analysis of GAG from embryonic mouse teeth is presented to demonstrate the usefulness of this method.

Effect of thyrotropin on glycosaminoglycans synthesized by primocultured thyroid cells

The synthesis of glycosaminoglycans (GAGs) was investigated in porcine thyroid cells under the influence or not of thyrotropin. After labelling with [3H] glucosamine and [35S] SO4(2-), enriched GAG-fractions prepared from culture media, cells, and eventually substrate adhering materials, were analyzed by cellulose acetate electrophoresis combined with specific degradations. They comprised heparan sulfate and hyaluronic acid together with an unknown sulfated component labile to endo-beta-galactosidase. Whereas global labellings of newly made GAGs were not significantly modified by thyrotropin, we reproducibly observed with the hormone a substantial increase in the proportion of hyaluronic acid [3H] label and, when cells organized into follicles, of the proportion of cell-associated [3H] GAGs. This system thus offers an interesting model to study how the responsiveness to an hormone and the reorganization that follows might implicate specific glycoconjugates.