Spatial distribution and orientation of dermatan sulfate in human medial collateral ligament

The proteoglycan decorin and its associated glycosaminoglycan (GAG), dermatan sulfate (DS), regulate collagen fibril formation, control fibril diameter, and have been suggested to contribute to the mechanical stability and material properties of connective tissues. The spatial distribution and orientation of DS within the tissue are relevant to these mechanical roles, but measurements of length and orientation from 2D transmission electron microscopy (TEM) are prone to errors from projection. The objectives of this study were to construct a 3D geometric model of DS GAGs and collagen fibrils, and to use the model to interpret TEM measurements of the spatial orientation and length of DS GAGs in the medial collateral ligament of the human knee. DS was distinguished from other sulfated GAGs by treating tissue with chondroitinase B, an enzyme that selectively degrades DS. An image processing pipeline was developed to analyze the TEM micrographs. The 3D model of collagen and GAGs quantified the projection error in the 2D TEM measurements. Model predictions of 3D GAG orientation were highly sensitive to the assumed GAG length distribution, with the baseline input distribution of 69+/-23 nm providing the best predictions of the angle measurements from TEM micrographs. The corresponding orientation distribution for DS GAGs was maximal at orientations orthogonal to the collagen fibrils, tapering to near zero with axial alignment. Sulfated GAGs that remained after chondroitinase B treatment were preferentially aligned along the collagen fibril. DS therefore appears more likely to bridge the interfibrillar gap than non-DS GAGs. In addition to providing quantitative data for DS GAG length and orientation in the human MCL, this study demonstrates how a 3D geometric model can be used to provide a priori information for interpretation of geometric measurements from 2D micrographs.     

Effect of sulfated glycosaminoglycan digestion on the transverse permeability of medial collateral ligament

Dermatan and chondroitin sulfate glycosaminoglycans (GAGs) comprise over 90% of the GAG content in ligament. Studies of their mechanical contribution to soft tissues have reported conflicting results. Measuring the transient compressive response and biphasic material parameters of the tissue may elucidate the contributions of GAGs to the viscoelastic response to deformation. The hypotheses of the current study were that digestion of sulfated GAGs would decrease compressive stress and aggregate modulus while increasing the permeability of porcine medial collateral ligament (MCL). Confined compression stress relaxation experiments were carried out on porcine MCL and tissue treated with chondroitinase ABC (ChABC). Results were fit to a biphasic constitutive model to derive permeability and aggregate modulus. Bovine articular cartilage was used as a benchmark tissue to verify that the apparatus provided reliable results. GAG digestion removed up to 88% of sulfated GAGs from the ligament. Removal of sulfated GAGs increased the permeability of porcine MCL nearly 6-fold versus control tissues. Peak stress decreased significantly. Bovine articular cartilage exhibited the typical reduction of GAG content and resultant decreases in stress and modulus and increases in permeability with ChABC digestion. Given the relatively small amount of GAG in ligament (<1% of tissue dry weight) and the significant change in peak stress and permeability upon removal of GAGs, sulfated GAGs may play a significant role in maintaining the apposition of collagen fibrils in the transverse direction, thus supporting dynamic compressive loads experienced by the ligament during complex joint motion.     

Effect of the gonadal status and the gender on glycosaminoglycans profile in the lower urinary tract of dogs

Glycosaminoglycans (GAGs) form a functional component of connective tissues that affect the structural and functional integrity of the lower urinary tract (LUT). The specific GAGs of physiological relevance are both nonsulfated (hyaluronan) and sulfated GAGs (chondroitin sulphate [CS], dermatan sulphate [DS], keratan sulphate [KS], and heparan sulphate [HS]). As GAG composition in the LUT is hormonally regulated, we postulated that gonadectomy-induced endocrine imbalance alters the profile of GAGs in the canine LUT. Four regions of the LUT (body and neck of the bladder as well as the proximal and distal urethra) from 20 clinically healthy dogs (5 intact males, 5 intact anoestrus females, 4 castrated males, and 6 spayed females) were collected, wax-embedded and sectioned. Alcian blue staining at critical electrolyte concentrations was performed on the sections to determine total GAGs, hyaluronan, total sulfated GAGs, combined components of CS and DS, as well as KS and HS. The amount of staining was evaluated in 3 tissue layers, i.e., epithelium, subepithelial stroma and muscle within a region. Overall, hyaluronan (67.1%) was the predominant GAG in the LUT. Among sulfated GAGs, a combined component of KS and HS was found to be 61.8% and 38.2% for CS and DS. Gonadal status significantly affected GAG profiles in the LUT (P < 0.01). All GAG components were lower (P < 0.05) in body of the bladder of gonadectomized dogs. Total sulfated GAGs and a combined component of KS and HS were lower (P < 0.05) in all 4 regions of gonadectomized dogs. Except for a combined component of CS and DS, decreases in all GAGs were found more consistently in the muscle compared to other tissue layers. Differences between genders became obvious only when considered along with the effect of gonadal status. In gonadectomized dogs, changes in GAG components in the LUT were more consistent in females compared to males; this may partly explain different levels of risk in the development of urinary incontinence between genders. Quantitative differences in GAG profiles found between intact and gonadectomized dogs indicate a potential role of gonadectomy-induced endocrine imbalance in modifying GAG composition in the canine LUT. Profound alteration in the pattern of GAGs in gonadectomized dogs may compromise structural and functional integrity of the LUT and is possibly involved in the underlying mechanism of urinary incontinence post neutering.     

Contributions of Glycosaminoglycans to Collagen Fiber Recruitment in Constitutive Modeling of Arterial Mechanics

The contribution of glycosaminoglycans (GAGs) to the biological and mechanical functions of biological tissue has emerged as an important area of research. GAGs provide structural basis for the organization and assembly of extracellular matrix (ECM). The mechanics of tissue with low GAG content can be indirectly affected by the interaction of GAGs with collagen fibers, which have long been known to be one of the primary contributors to soft tissue mechanics. Our earlier study showed that enzymatic GAG depletion results in straighter collagen fibers that are recruited at lower levels of stretch, and a corresponding shift in earlier arterial stiffening (Mattson et al., 2016). In this study, the effect of GAGs on collagen fiber recruitment was studied through a structure-based constitutive model. The model incorporates structural information, such as fiber orientation distribution, content, and recruitment of medial elastin, medial collagen, and adventitial collagen fibers. The model was first used to study planar biaxial tensile stress-stretch behavior of porcine descending thoracic aorta. Changes in elastin and collagen fiber orientation distribution, and collagen fiber recruitment were then incorporated into the model in order to predict the stress-stretch behavior of GAG depleted tissue. Our study shows that incorporating early collagen fiber recruitment into the model predicts the stress-stretch response of GAG depleted tissue reasonably well (rms = 0.141); considering further changes of fiber orientation distribution does not improve the predicting capability (rms = 0.149). Our study suggests an important role of GAGs in arterial mechanics that should be considered in developing constitutive models.     

Exogenous addition of a C-xylopyranoside derivative stimulates keratinocyte dermatan sulfate synthesis and promotes migration

As C-Xyloside has been suggested to be an initiator of glycosaminoglycan (GAG) synthesis, and GAGs such as Dermatan sulfate (DS) are potent enhancers of fibroblast growth factor (FGF)--10 action, we investigated if a C-Xylopyranoside derivative, (C-β-D-xylopyranoside-2-hydroxy-propane, C-Xyloside), could promote DS production by cultured normal human keratinocytes, how this occurs and if C-Xyloside could also stimulate FGF-dependent cell migration and proliferation. C-Xyloside-treated keratinocytes greatly increased secretion of total sulfated GAGs. Majority of the induced GAG was chondroitin sulfate/dermatan sulfate (CS/DS) of which the major secreted GAG was DS. Cells lacking xylosyltransferase enzymatic activity demonstrated that C-Xyloside was able to stimulate GAG synthesis without addition to core proteins. Consistent with the observed increase in DS, keratinocytes treated with C-Xyloside showed enhanced migration in response to FGF-10 and secreted into their culture media GAGs that promoted FGF-10-dependent cellular proliferation. These results indicate that C-Xyloside may enhance epithelial repair by serving as an initiator of DS synthesis.     

Examination of corneal proteoglycans and glycosaminoglycans by rotary shadowing and electron microscopy

Proteoglycans (PGs) from cornea and their relevant glycosaminoglycan (GAG) chains, dermatan sulphate (DS) and keratin sulphate (KS), were examined by electron microscopy following rotary shadowing, and compared with hyaluronan (HA), chondroitin sulphate (CS), alginate, heparin, heparan sulphate (HS) and methyl cellulose. Corneal DS PG had the tadpole shape previously seen in scleral DS FG, and the images from corneal KS PG could be interpreted similarly, although the GAG (KS) chains were very much fainter than those of DS PG GAG. Isolated GAG (KS, DS, CS, HA, etc.) examined in the same way showed images that decreased very significantly in clarity and contrast, in the sequence HA greater than DS greater than CS greater than KS. The presence of secondary and tertiary structures in the GAGs may be at least partly responsible for these variations. HA appeared to be double stranded, and DS frequently self-aggregated, KS and HS showed tendencies to coil into globular shapes. It is concluded that it is unsafe to assume the absence of GAGs, based on these techniques, and quantitative measurements of length may be subject to error. The results on corneal DS PG confirm and extend the hypothesis that PGs specifically associated with collagen fibrils are tadpole shaped.     

Low sulfated glycosaminoglycans are excreted in patients with the Lowe syndrome

Glycosaminoglycans (GAGs) were prepared from the urine of three patients and from normal individuals by cetylpyridinium chloride precipitation and Pronase digestion. The GAGs were analyzed by electrophoresis, anion-exchange chromatography, and enzymatic and chemical degradation. Each of the three patients showed a four- to fivefold increase in urinary GAG excretion compared to normal controls and in one patient a tenfold increase was measured during a period of behavioral agitation which included joint swelling. Urinary GAGs from affected individuals were characterized by a high proportion of low sulfated molecules. The predominant low sulfated component was chondroitin-4-sulfate (C4S); however, small amounts of chondroitin-6-sulfate (C6S) were also present. Heparan sulfate (HS) was present in normal proportion (5-10%) and most of it was not low sulfated. Abnormal excretion of chondroitin (Ch), hyaluronic acid (HA), and dermatan sulfate (DS) was not detected. These findings suggest that the clinical manifestations of Lowe syndrome may be caused by a defect in GAG metabolism.     

Modulation of sulfated glycosaminoglycan and small proteoglycan synthesis by the extracellular matrix

Cell culture in collagen lattice is known to be a more physiological model than monolayer for studying the regulation of extracellular matrix protein deposition. The synthesis of sulfated glycosaminoglycans (GAG) and dermatan sulfate (DS) proteoglycans by 3 cell strains were studied in confluent monolayers grown on plastic surface, in comparison to fully retracted collagen lattices. Cells were labelled with³⁵S-sulfate, followed by GAG and proteoglycan analysis by cellulose acetate and SDS-polyacrylamide gel electrophoresis, respectively. The 3 cell strains contracted the lattice in a similar way. In monolayer cultures, the major part of GAG was secreted into culture medium whereas in lattice cultures of dermal fibroblasts and osteosarcoma MG-63 cells but not fibrosarcoma HT-1080 cells, a higher proportion of GAGs, including dermatan sulfate, was retained within the lattices. Small DS proteoglycans, decorin and biglycan, were detected in fibroblasts and MG-63 cultures. They were preferentially trapped within the collagen gel. In retracted lattices, decorin had a higher M_r than in monolayer. Biglycan was detected in monolayer and lattice cultures of MG-63 cells but in lattice cultures only in the case of fibroblasts. In this last case, an up regulation of biglycan mRNA steady state level and down regulation of decorin mRNA was observed, in comparison to monolayers, indicating that collagen can modulate the phenotypical expression of small proteoglycan genes.Supported by a fellowship from the Centre National de la Recherche Scientifique     

Turnover of sulfated glycosaminoglycans in fibroblasts derived from patients with Werner''s syndrome

Fibroblasts derived from patients with Werner's syndrome (WS) were incubated with radioactive sulfate to study the incorporation of 35S into glycosaminoglycans (GAGs). The accumulation of cell-associated 35S radioactivity in the GAGs of WS fibroblasts was consistently higher than parallel accumulation in normal human fibroblasts, but was substantially less than in fibroblasts derived from patients with Hurler's syndrome (HS). However, when fibroblasts were labeled with 35SO4(2-), trypsinized to remove extracellular and pericellular radioactive GAGs, replated, and chased to follow the fate of the intracellular radioactivity, both WS and normal cells showed a rapid release of the intracellular 35S, while HS cells showed little or no loss of intracellular radioactivity. The radioactivity released from WS and normal cells was of low molecular weight (LMW), eluting from gel filtration columns at the same position as free sulfate. These results establish that WS cells degrade intracellular sulfated GAGs and argue against the hypothesis that a defect in GAG degradation pathways is the basis for the increased level of cell-associated GAGs. Other possible explanations for the increased cell-associated [35S]GAGs in WS cells as compared with normal cells were also considered: increased GAG sulfation; an increase in GAG chain length; an increased rate of GAG synthesis; and a decreased rate of shedding of cell surface proteoglycan into the medium. No difference between normal and WS fibroblasts in any of the above parameters was observed. These results strongly imply that the primary biochemical defect in WS fibroblasts does not involve sulfated GAG metabolism.     

Identification and tissue-specific distribution of sulfated glycosaminoglycans in the blood-sucking bug Rhodnius prolixus (Linnaeus)

We have previously characterized heparan sulfate (HS) as the major ovarian sulfated glycosaminoglycan (GAG) in females of Rhodnius prolixus, while chondroitin sulfate (CS) was the minor component. Using histochemical procedures we found that GAGs were concentrated in the ovarian tissue but not found inside the oocytes. Here, we extend our initial observations of GAG expression in R. prolixus by characterizing these molecules in other organs: the fat body, intestinal tract, and the reproductive tracts. Only HS and CS were found in the three organs analyzed, however CS was the major GAG species in these tissues. We also determined the compartmental distribution of GAGs in these organs by histochemical analysis using 1,9-dimethylmethylene blue, and evaluated the specific distribution of CS within both male and female reproductive tracts by immunohistochemistry using an anti-CS antibody. We also determined the GAG composition in eggs at days 0 and 6 of embryonic development. Only HS and CS were found in eggs at day 6, while no sulfated GAGs were detected at day 0. Our results demonstrate that HS and CS are the only sulfated GAG species expressed in the fat body and in the intestinal and reproductive tracts of Rhodnius male and female adults. Both sulfated GAGs were also identified in Rhodnius embryos. Altogether, these results show no qualitative differences in the sulfated GAG composition regarding tissue-specific or development-specific distribution.     

Regional variation in the mechanical role of knee meniscus glycosaminoglycans

High compressive properties of cartilaginous tissues are commonly attributed to the sulfated glycosaminoglycan (GAG) fraction of the extracellular matrix (ECM), but this relationship has not been directly measured in the knee meniscus, which shows regional variation in GAG content. In this study, biopsies from each meniscus region (outer, middle, and inner) were either subjected to chondroitinase ABC (CABC) to remove all sulfated GAGs or not. Compressive testing revealed that GAG depletion in the inner and middle meniscus regions caused a significant decrease in modulus of relaxation (58% and 41% decreases, respectively, at 20% strain), and all regions exhibited a significant decrease in viscosity (outer: 29%; middle: 58%; inner: 62% decrease). Tensile properties following CABC treatment were unaffected for outer and middle meniscus specimens, but the inner meniscus displayed significant increases in Young's modulus (41% increase) and ultimate tensile stress (40% increase) following GAG depletion. These findings suggest that, in the outer meniscus, GAGs contribute to increasing tissue viscosity, whereas in the middle and inner meniscus, where GAGs are most abundant, these molecules also enhance the tissue's ability to withstand compressive loads. GAGs in the inner meniscus also contribute to reducing the circumferential tensile properties of the tissue, perhaps due to the pre-stress on the collagen network from increased hydration of the ECM. Understanding the mechanical role of GAGs in each region of the knee meniscus is important for understanding meniscus structure-function relationships and creating design criteria for functional meniscus tissue engineering efforts.     

Interactions of hepatocyte growth factor/scatter factor with various glycosaminoglycans reveal an important interplay between the presence of iduronate and sulfate density

Hepatocyte growth factor/scatter factor (HGF/SF) has a cofactor requirement for heparan sulfate (HS) and dermatan sulfate (DS) in the optimal activation of its signaling receptor MET. However, these two glycosaminoglycans (GAGs) have different sugar backbones and sulfation patterns, with only the presence of iduronate in common. The structural basis for GAG recognition and activation is thus very unclear. We have clarified this by testing a wide array of natural and modified GAGs for both protein binding and activation. Comparisons between Ascidia nigra (2,6-O-sulfated) and mammalian (mainly 4-O-sulfated) DS species, as well as between a panel of specifically desulfated heparins, revealed that no specific sulfate isomer, in either GAG, is vital for interaction and activity. Moreover, different GAGs of similar sulfate density had comparable properties, although affinity and potency notably increase with increasing sulfate density. The weaker interaction with CS-E, compared with DS, shows that GlcA-containing polymers can bind, if highly sulfated, but emphasizes the importance of the flexible IdoA ring. Our data indicate that the preferred binding sites in DS in vivo will be comprised of disulfated, IdoA(2S)-containing motifs. In HS, clustering of N-/2-O-/6-O-sulfation in S-domains will lead to strong reactivity, although binding can also be mediated by the transition zones where sulfates are mainly at the N- and 6-O- positions. GAG recognition of HGF/SF thus appears to be primarily driven by electrostatic interactions and exhibits an interesting interplay between requirements for iduronate and sulfate density that may reflect in part a preference for particular sugar chain conformations.     

花背蟾蜍角膜早期发育中氨基多糖的电镜细胞化学研究

Glycosaminoglycans (GAGs) and their changes in early corneal development of Bufo raddei Strauch (from stage 16, neural tube, to stage 25, operculum completely closed) were studied with electron microscopic cytochemical method. Results show that synthesis of GAGs changes from non-sulfated to sulfated, and its content increased gradually with the development of cornea. Hyaluronic acid (HA) in each part of cornea begins to increase gradually from stage 16 to 21 (mouth open stage), with its peak at stage 20 (gill circulation stage) to 21, then decreases. In the mean time, contents of dermatam sulfate (DS), chondroitin sulfate (CS), heparan sulfate (HS) and heparin (Hep) increase gradually. It is considered that HA, HS and collagen may be related to the migration of mesenchymal cells, and HA promotes the expansion and hydration of corneal stroma; sulfated GAGs are correlated with dehydration of cornea, cell density and corneal transparency; DS, CS, HS and Hep deposited among collagen fibrils could adjust their arrangement. All these changes would enhance transparency of cornea.     

An automated mass spectrometry-based screening method for analysis of sulfated glycosaminoglycans

Glycosaminoglycans (GAGs) are linear polysaccharides, consisting of repeated disaccharide units, attached to core proteins in all multicellular organisms. Chondroitin sulfate (CS) and dermatan sulfate (DS) constitute a subgroup of sulfated GAGs for which the degree of sulfation varies between species and tissues. One major goal in GAG characterization is to correlate structure to function. A common approach is to exhaustively degrade the GAG chains and thereafter determine the amount of component disaccharide units. In large-scale studies, there is a need for high-throughput screening methods since existing methods are either very time- or samples consuming. Here, we present a new strategy applying MALDI-TOF MS in positive ion mode for semi-qualitative and quantitative analysis of CS/DS derived disaccharide units. Only a few picomoles of sample are required per analysis and 10 samples can be analyzed in 25 min, which makes this approach an attractive alternative to many established assay methods. The total CS/DS concentration in 19 samples derived from Caenorhabditis elegans and mammalian tissues and cells was determined. The obtained results were well in accordance with concentrations determined by a standard liquid chromatography-based method, demonstrating the applicability of the method for samples from various biological matrices containing CS/DS of different sulfation degrees.     

The regional contribution of glycosaminoglycans to temporomandibular joint disc compressive properties

Understanding structure-function relationships in the temporomandibular joint (TMJ) disc is a critical first step toward creating functional tissue replacements for the large population of patients suffering from TMJ disc disorders. While many of these relationships have been identified for the collagenous fraction of the disc, this same understanding is lacking for the next most abundant extracellular matrix component, sulfated glycosaminoglycans (GAGs). Though GAGs are known to play a major role in maintaining compressive integrity in GAG-rich tissues such as articular cartilage, their role in fibrocartilaginous tissues in which GAGs are much less abundant is not clearly defined. Therefore, this study investigates the contribution of GAGs to the regional viscoelastic compressive properties of the temporomandibular joint (TMJ) disc. Chondroitinase ABC (C-ABC) was used to deplete GAGs in five different disc regions, and the time course for >95% GAG removal was defined. The compressive properties of GAG depleted regional specimens were then compared to non-treated controls using an unconfined compression stress-relaxation test. Additionally, treated and non-treated specimens were assayed biochemically and histologically to confirm GAG removal. Compared to untreated controls, the only regions affected by GAG removal in terms of biomechanical properties were in the intermediate zone, the most GAG-rich portion of the disc. Without GAGs, all intermediate zone regions showed decreased tissue viscosity, and the intermediate zone lateral region also showed a 12.5% decrease in modulus of relaxation. However, in the anterior and posterior band regions, no change in compressive properties was observed following GAG depletion, though these regions showed the highest compressive properties overall. Although GAGs are not the major extracellular matrix molecule of the TMJ disc, they are responsible for some of the viscoelastic compressive properties of the tissue. Furthermore, the mechanical role of sulfated GAGs in the disc varies regionally in the tissue, and GAG abundance does not always correlate with higher compressive properties. Overall, this study found that sulfated GAGs are important to TMJ disc mechanics in the intermediate zone, an important finding for establishing design characteristics for future tissue engineering efforts.     

Determination of galactosamine impurities in heparin sodium using fluorescent labeling and conventional high-performance liquid chromatography

Heparin is a sulfated glycosaminoglycan (GAG), which contains N-acetylated or N-sulfated glucosamine (GlcN). Heparin, which is generally obtained from the healthy porcine intestines, is widely used as an anticoagulant during dialysis and treatments of thrombosis such as disseminated intravascular coagulation. Dermatan sulfate (DS) and chondroitin sulfate (CS), which are galactosamine (GalN)-containing GAGs, are major process-related impurities of heparin products. The varying DS and CS contents between heparin products can be responsible for the different anticoagulant activities of heparin. Therefore, a test to determine the concentrations of GalN-containing GAG is essential to ensure the quality and safety of heparin products. In this study, we developed a method for determination of relative content of GalN from GalN-containing GAG in heparin active pharmaceutical ingredients (APIs). The method validation and collaborative study with heparin manufacturers and suppliers showed that our method has enough specificity, sensitivity, linearity, repeatability, reproducibility, and recovery as the limiting test for GalN from GalN-containing GAGs. We believe that our method will be useful for ensuring quality, efficacy, and safety of pharmaceutical heparins. On July 30, 2010, the GalN limiting test based on our method was adopted in the heparin sodium monograph in the Japanese Pharmacopoeia.     

Selection and characterization of a unique phage display-derived antibody against dermatan sulfate.

Dermatan sulfate (DS) is a member of the glycosaminoglycan (GAG) family and is primarily located in the extracellular matrix. Using a modified phage display procedure, we selected 2 different antibodies against DS of which one antibody, LKN1, was specific for DS. LKN1 was especially reactive with 4/2,4-di-O-sulfated DS, and did not react with other classes of GAGs including chondroitin sulfate and heparan sulfate. Immunohistochemical analysis of kidney, skin and tendon showed a typical fibrillar staining pattern, co-localizing with type I collagen. Staining was abolished by specific enzymatic digestion of DS. Immunoelectron microscopy confirmed the association of the DS epitope with collagen fibrils. The location of DS did not follow the main banding period of collagen, which is in line with the current concept that the core protein rather than the DS moiety of DS-proteoglycans specifically binds to collagen fibrils. This unique anti-DS antibody and the availability of its coding DNA may be instrumental in studies of the structure and function of DS.     

Effect of glucocorticoid on glycosaminoglycans synthesis in cultured mouse embryonic palatal mesenchymal cells

The effect of glucocorticoids (GC) on the synthesis of glycosaminoglycans (GAGs) in mesenchymal cells obtained from palatal shelves of mouse embryos was studied. Both hyaluronic acid (HA) synthesis and sulfated GAG synthesis were inhibited with triamcinolone acetonide (TA) in a concentration-dependent manner. However, the degree of inhibition of synthesis with TA was greater for HA than for the sulfated GAGs. To determine whether the inhibitory effects of TA on HA and sulfated GAGs synthesis were mediated through GC receptors, we performed experiments using progesterone, vitamin B6, and molybdate. The inhibitory effect of TA was antagonized by all three. The results obtained in the present study suggest that the inhibition of synthesis of HA and sulfated GAGs with GC is mediated through GC receptors and is involved in cleft palate induction by GC.     

Immunocytochemical study of tissue distribution and hormonal control of chondroitin-, dermatan- and keratan sulfates from rodent uterus

The distribution patterns of rat and mouse uterine glycosaminoglycans (GAGs), as well as their modulation by estradiol (E2) and/or progesterone (P), were investigated using monoclonal antibodies (MABs) directed against chondroitin- (CS)/dermatan sulfates (DS), keratan sulfate (KS) and a trophoblast GAG. The localization of GAGs in relation to collagens (I, IV and VI) and fibronectin was also analyzed. We found that uterine GAGs are differentially distributed in the endometrium and myometrium, in a pattern that is species-related. CS-containing proteoglycans (PGs) occur between collagen bundles and fibroblasts, at the periphery of the latter, and in basement membrane zones (BMZs), in a pattern resembling that of collagen VI. BMZs contain preferentially CS-PGs bearing 4-sulfated disaccharides adjacent to the core protein. DS-PGs are mostly associated with collagen bundles. E2 and/or P elicit distinct modifications on the above described pattern, which are also species-related. The simultaneous administration of E2 and P changes the prevalent sulfation of the disaccharides adjacent to the core protein of stromal CS-PGs. In the mouse, an unsulfated intracellular epitope appears following E2 (or E2P) administration, mostly in epithelial cells. In the rat, KS and the trophoblast GAG are E2-dependent and down-regulated by P. The functional significance of the hormone-induced GAG changes, namely the possible role of the E2-dependent KS in implantation, are discussed.