Modification of cell surface glycoprotein: addition of fucosyl residues during epidermal differentiation

Mucociliary transport, differential white blood cells, and cyto-genotoxicity in peripheral erythrocytes in fish from a polluted urban pond

The present study evaluated the water quality of a polluted pond through the analysis of in vitro mucociliary transport, hematological parameters, and biomarkers of cyto-genotoxicity in the Nile tilapia (Oreochromis niloticus). Blood and mucus samples were collected from ten specimens from the polluted pond and from ten specimens from a control area. The fish were anesthetized with 3% benzocaine, mucus was collected directly from the gills, and blood was drawn from the caudal artery. Blood smears were stained using the May-Grünwald Giemsa process for the differential leukocyte counts and to determine the frequency of leukocytes, thrombocytes, erythroblasts, micronuclei, and nuclear abnormalities. The results revealed low transportability in vitro, a high percentage of monocytes and eosinophils, and increased frequency of leukocytes and nuclear abnormalities in fish from the polluted pond. However, the frequency of thrombocytes and erythroblasts and the percentage of lymphocytes and neutrophils were significantly lower. It is possible to conclude that changes in fish are due to poor water quality and that these non-destructive biomarkers can be used for the biomonitoring of aquatic environments vulnerable to contamination.

Kinetics of acute infection with Toxoplasma gondii and histopathological changes in the duodenum of rats

Toxoplasma gondii crosses the intestinal barrier to spread into the body. We investigate the intestinal wall and epithelial cells of the duodenum of rats infected with T. gondii during different time points of acute infection. Male Wistar rats, 60 days of age, were assigned into groups that were orally inoculated with 5000 sporulated oocysts T. gondii for 6 h (G6), 12 h (G12), 24 h (G24), 48 h (G48), 72 h (G72), 7 days (G7d), and 10 days (G10d). The control group (CG) received saline. The rats were killed and the duodenum was processed to obtain histological sections stained with hematoxylin and eosin, Periodic Acid Schiff, and Alcian blue (pH 2.5 and 1.0). Morphometry was performed on the layers of the intestinal wall and enterocytes, and the number of goblet cells and intraepithelial lymphocytes was counted. The data were compared by ANOVA considering 5% as level of significance. The infection provoked an increase in the width of villi and crypts; decrease in enterocyte height; increase in the smaller-diameter and reduction in the larger-diameter of the enterocytes nuclei, increased number of goblet cells secreting neutral (G6, G12 and G7d) and acidic (G7d and G10d) mucus, and increase in the number of intraepithelial lymphocytes (G48). The infected groups showed atrophy of the submucosa and muscular layers and the total wall. Acute infection with T. gondii caused morphological changes in the intestinal wall and epithelial cells of the duodenum in rats.

Development of an advanced intestinal in vitro triple culture permeability model to study transport of nanoparticles

Intestinal epithelial cell culture models, such as Caco-2 cells, are commonly used to assess absorption of drug molecules and transcytosis of nanoparticles across the intestinal mucosa. However, it is known that mucus strongly impacts nanoparticle mobility and that specialized M cells are involved in particulate uptake. Thus, to get a clear understanding of how nanoparticles interact with the intestinal mucosa, in vitro models are necessary that integrate the main cell types. This work aimed at developing an alternative in vitro permeability model based on a triple culture: Caco-2 cells, mucus-secreting goblet cells and M cells. Therefore, Caco-2 cells and mucus-secreting goblet cells were cocultured on Transwells and Raji B cells were added to stimulate differentiation of M cells. The in vitro triple culture model was characterized regarding confluence, integrity, differentiation/expression of M cells and cell surface architecture. Permeability of model drugs and of 50 and 200 nm polystyrene nanoparticles was studied. Data from the in vitro model were compared with ex vivo permeability results (Ussing chambers and porcine intestine) and correlated well. Nanoparticle uptake was size-dependent and strongly impacted by the mucus layer. Moreover, nanoparticle permeability studies clearly demonstrated that particles were capable of penetrating the intestinal barrier mainly via specialized M cells. It can be concluded that goblet cells and M cells strongly impact nanoparticle uptake in the intestine and should thus be integrated in an in vitro permeability model. The presented model will be an efficient tool to study intestinal transcellular uptake of particulate systems.

Mucin 21 in esophageal squamous epithelia and carcinomas: analysis with glycoform-specific monoclonal antibodies

Monoclonal antibodies (mAbs) against mucin 21 (MUC21), a human counterpart of mouse epiglycanin/Muc21, were prepared using human embryonic kidney 293 cells transfected with MUC21 as the immunogen. The specificity of these mAbs was examined by flow cytometry, immunoprecipitation and western blotting focusing on the differential glycosylation of MUC21 expressed in variant Chinese hamster ovary (CHO) cells (ldlD cells and Lec2 cells) and CHO-K1 cells. One of these mAbs, heM21D, bound to both the unmodified core polypeptide of MUC21 and MUC21 attached with N-acetylgalactosamine (Tn-MUC21). Six antibodies, including mAb heM21C, bound to MUC21 with Tn, T or sialyl-T epitopes but not the unmodified core polypeptide of MUC21. Esophageal squamous carcinomas and adjacent squamous epithelia were immunohistochemically examined for the binding of these mAbs. MUC21 was expressed in esophageal squamous epithelial cells, and its O-glycan extended forms were observed in the luminal portions of squamous epithelia. As revealed by the binding of mAb heM21D and the absence of reactivity with mAb heM21C, esophageal squamous carcinoma cells produce MUC21 without the attachment of O-glycans. This is the first report to show that there is a change in the glycoform of MUC21 that can be used to differentiate between squamous epithelia and squamous carcinoma of the esophagus. Thus, these antibodies represent a useful tool to characterize squamous epithelial differentiation and carcinogenesis.

Carbohydrate expression and modification during keratinocyte differentiation in normal human and reconstructed epidermis

Using fluorescein isothiocyanate (FITC)-labeled lectins we were able to demonstrate the presence of specific carbohydrate moieties in normal human and reconstructed epidermis. Evidence is provided that in both cases the strongly reduced lectin staining at the level of the stratum corneum is the result of a hindered accessibility of the lectins in this lipid-rich hydrophobic environment. Isolated corneocytes and purified cornified envelopes (CEs) exhibited clearly glycosylated structures reacting with distinct lectins. The presence of glycosidase activity, particularly in the upper layers of the epidermis characterized by an acidic environment (pH 5.5), indicates that modifications of the sugar residues might be important in epidermal homeostasis, barrier behavior and desquamation. Absent or strongly reduced glycosidase activity in the stratum corneum of reconstructed epidermis with an impaired pH gradient could be in part responsible for the reduced barrier function and the lack of desquamation in this model.

Lectin histochemistry on the dorsal epidermis of the Breton dog

Expression of sugar residues and the nature of oligosaccharide linkage during keratinocyte maturation in the epidermis of the Breton dog were studied with the use of lectin histochemistry. Thirteen lectins were used. Labelling was not observed with GSA I-B4, GSA II, UEA-I, and LTA. The cytoplasm of keratinocytes reacted with PNA, HPA, Con A, and WGA from the basal layer to the granular layer. PNA and Con A showed highest reactivity in the granular cell layer. The cell surface showed increased reactivity with PNA, HPA, and WGA with maturation of keratinocytes. KOH-neuraminidase treatment (KOH-Neu) increased PNA and RCA120 staining during keratinocyte differentiation thus indicating an increase in oligosaccharides terminating with sialic acid-Galbeta(1,3)GalNAc and sialic acid-Galbeta(1,4)GlcNAc, respectively. Labelling of the glycocalyx of basal and spinous keratinocytes with SNA and MAA revealed terminal Neu5acalpha(2,6)Gal/GalNAc and Neu5acalpha(2,3)Galbeta(1,4)GlcNAc. KOH-Neu-DBA showed oligosaccharides terminating with sialic acid-GalNAcalpha(1,3)GalNAc in the spinous and granular layers. A selective glycocalyx labelling of granular keratinocytes was observed with DBA and SBA. Reactions with MAA, PNA, DBA, RCA120, SBA, HPA, and WGA disappeared after the beta-elimination reaction. Our findings indicate that Breton dog epidermis contains more O-linked than N-linked oligosaccharides and confirm that different subpopulations of keratinocytes can be distinguished by lectin histochemistry.

Lectin histochemistry of glycoconjugates in the feline hair follicle and hair

The distribution of glycoconjugate in the feline hair follicle and hair was studied by light and electron microscopic histochemical methods. The hair apparatus was found to contain considerable amounts of complex carbohydrates with different saccharide residues (alpha-D-mannose, beta-D-glucose, alpha-L-fucose, beta-N-acetyl-D-glucosamine). Variations of those were detected in the plasma membrane of the hair follicle cells during the course of their differentiation and keratinization, namely, alph-D-glucose, alpha-L-fucose and beta-N-acetyl-D-glucosamine in the suprabulbar and bulbar regions. The reaction level of sialic acid residues in the plasma membrane decreased in some cell layers during the course of differentiation. The results obtained from the present study indicated that interaction between saccharide residues of neutral carbohydrates and sialyl groups during the anagen phase might contribute to cell keratinization in hair follicles and hairs. It is discussed whether the existence of glycogen in outer root sheath cells might enable these cells to provide other hair apparatus cells with energy when necessary. Moreover, it became obvious from variations in sialyl residue distribution that cell differentiation processes terminate first of all in Huxley's and Henle's layers within the suprabulbar region of the hair follicle, as followed by the hair cortex.

Blood-group-related carbohydrates are expressed in organotypic cultures of human skin and oral mucosa

Cellular maturation and migration are usually associated with changes in cell-surface carbohydrates, but the relationship between these changes and cell behaviour is at present largely unknown. To investigate whether an organotypic culture system can be used as an in vitro model to study the function of cell-surface carbohydrates, we established organotypic cultures of skin and buccal mucosa. In these cultures, keratinocytes are grown at the air-liquid interface on a supporting matrix consisting of homologous fibroblasts embedded in a collagen type I gel. We examined the expression of blood-group-related carbohydrate structures, including Lewis x, sialylated Lewis x, Lewis y, Lewis a, and Lewis b, on the surface of epithelial cells in the cultures. We compared the results with the expression of more well-established markers, including cytokeratins, integrins, bullous pemphigoid antigen and laminin, in the same cultures. The organotypic skin and oral mucosa cultures showed a histological differentiation pattern analogous to that of normal skin and buccal mucosa, and a tissue-specific expression of carbohydrate structures and cytokeratins. However, both types of organotypic cultures also expressed markers which are normally seen during wound healing, including Lewis y, cytokeratin 16, and cytokeratin 19. We conclude that the organotypic cultures of oral mucosa and skin are suitable models for future studies of the function of cell-surface carbohydrates, although the expression of wound healing markers has to be taken into consideration.

A lectin histochemistry comparative study in human normal prostate, benign prostatic hyperplasia, and prostatic carcinoma

The partial oligosaccharide sequences of glycoconjugates and the nature of their glycosidic linkages were investigated in normal human prostate, benign prostatic hyperplasia (BPH) and prostatic carcinoma by means of lectin histochemistry, using light microscopy and Western blot analysis. The labeling pattern of BPH differed from that of normal prostate in having more intense staining with DSA, HPA, UEA-I and AAA, and in showing lesser staining with WGA and SBA. Prostatic carcinoma differed from normal prostates in displaying the more intense labeling with PNA, DSA, SBA, DBA, UEA-I and AAA, and in having lesser labeling with WGA. The main differences in labeling pattern between prostatic carcinoma and BPH were that the latter specimens showed more marked staining with PNA, DSA, DBA, SBA, UEA-I and AAA, and lesser staining with WGA and HPA. The staining patterns of SNA, MAA, ConA, LCA and GNA were similar in all three groups of specimens. For most of the lectins studied, including those showing a similar immunohistochemical staining in the three groups of specimens studied, the Western blot analysis showed differences in the banding pattern among normal, hyperplastic, and carcinomatous prostates. Present results suggest that the glycosylation of proteins was modified in both BPH and prostatic carcinoma. In BPH a strong expression of N-acetylgalactosamine residues occurred, while in prostatic carcinoma an increase of sialic acid, galactose and fucose residues was observed. No changes in mannose residues were detected.

Histology and lectin-binding patterns in the digestive tract of the carnivorous larvae of the anuran, Ceratophrys ornata

Larvae of Ceratophrys ornata are carnivorous, have relatively short digestive tracts and continue to feed during metamorphic climax, in contrast to those of more typical herbivorous anuran larvae. The present study describes both histological and histochemical changes in the stomach, small intestine, and large intestine of C. ornata prior to and during metamorphic climax. Modifications in these organs were found to be similar to but less dramatic than those in herbivorous larvae. Luminal epithelial cells in the three regions develop vacuoles, suggesting degeneration, but sloughing of this epithelium, as occurs in herbivorous larvae, was not observed in C. ornata. Multicellular tubular glands develop gradually in the gastric area during the larval stages, gastric pits appear during metamorphic climax, and mucous neck cells are first visible in the juvenile. Goblet cells in the small and large intestine increase in number during larval life, as do the number of folds in the intestinal wall. Increase in diameter and thickness of the wall occurs in the stomach as well as in the small and large intestine. Such changes result in an adult-type digestive tract characteristic of frogs in general. Staining with two horseradish peroxidase conjugated lectins, soybean agglutinin (SBA) and Ulex europaeus agglutinin I (UEA I), demonstrated specific sites along the digestive tract of glycoconjugates with terminal sugars N-acetylgalactosamine and alpha-fucose, respectively. As metamorphic climax approaches, staining intensities decrease--thus providing evidence for metamorphic changes in the sugar moieties of glycoconjugates present in the digestive tract of carnivorous larvae.

Changes in expression of the oligosaccharides in the human fetal skin

Lectin histochemistry was used to investigate the glycoconjugate saccharidic moieties in the skin of human fetuses ranging in age from the 8th to the 13th week of gestation. For this purpose, seven HRP-conjugated lectins were employed (Con A, WGA, PNA, DBA, SBA, UEAI and LTA). The distribution and changes of the sugar residues of glycoconjugates at the level of the various layers of the fetal epidermis, as well of the underlying mesenchyme were studied. We have shown that UEAI reactivity is a characteristic finding of the cells of the intermediate layer at the 11th and 12th week of gestation. LTA reactivity was detected only at the free border of the peridermal cells from the 10th to the 13th week of gestation. We demonstrated the presence of PNA binding sites at both the basal and peridermal cells from the 8th week of gestation, whereas other authors have stated that the appearance of PNA reactivity coincides with the onset of fetal skin stratification (11th-12th week of gestation). Moreover, some typical features in lectin reactivity at the level of the mesenchymal cells and fibres have been pointed out.

Histochemical study of lectin binding in the human fetal minor salivary glands

The emerging synthesis of glycoconjugates containing specific oligosaccharides in developing human fetal labial and lingual salivary glands has been investigated by lectin histochemistry. An avidin-biotin technique was used to study the binding of lectins from Ulex europeus I (UEA-I), Dolichos biflorus (DBA), Glycine maximus (SBA), Helix pomatia (HPA), Arachis hypogaea (PNA) and Triticum vulgare (WGA) to specific sugars on sections of tissue from labial glands, glands of Blandin and Nuhn, glands of von Ebner and the dorsoposterior lingual salivary glands. Incipient synthesis of glycoconjugates in early glands and their presence in the cells and ducts of the later glands was shown. The study also showed a time-related increase in both staining intensity and binding sites of serous acinar cells from all glands and for all lectins used. For mucous cells, peak intensity of staining was reached by the middle phase of development. During later gland development this intensity was maintained in dorsoposterior lingual glands but tended to decline in labial glands. The various lectins showed different degrees of binding but UEA-I lectin generally bound the L-fucose sugar group in all salivary glands at all gestational ages. The results showed that lectins appear to bind to the oligosaccharides on epithelial cell surfaces of fetal salivary glands at all stages of development. The degree of change depends upon the stage of differentiation and maturation of the glands.

Down-regulation of membrane glycoprotein in amoeboid microglia transforming into ramified microglia in postnatal rat brain

The present study describes the ultrastructural localization and labelling pattern of lectin in different microglial cell phenotypes in the postnatal rat brain using the isolectin, GSA I-B4. The nascent round and amoeboid microglial cells (round cells and cells displaying short processes) were labelled at their cytoplasmic membrane and the membrane of the subplasmalemmal vacuoles. In the course of their transformation into ramified forms with age, dense lectin labelling was observed successively at different sites in the differentiating cells. The most striking feature was the staining of the Golgi saccules on the trans face, the trans tubular network and associated vesicles and vacuoles in the 'intermediate' ramified microglia (ramified cells bearing thick and long processes and those with thin and long processes). The vacuoles with accumulated reaction products were closely associated with many microtubules extending into the cytoplasmic processes. At the surface, the lectin-labelled vacuoles and vesicles appeared to fuse with the membrane and their contents communicated with the exterior. In the advanced or most differentiated ramified microglial cells (cells bearing attenuated processes), the lectin staining at all the above mentioned sites became diminished. In conclusion, in the transformation of the round microglia into their ramified derivatives, the glycoconjugates at the cytoplasmic membrane are progressively reduced. It is postulated from this study that the down-regulation of the glycoconjugates of the microglial plasma membrane is due primarily to their internalization during endocytosis. This process would trigger a de novo galactosyl protein synthesis and/or modification at the trans Golgi saccules and trans tubular network probably in an attempt to degrade the internalized membrane glycoproteins or to replenish the consumption of the membrane glycoconjugates.

Sialyl LewisX expression on human Langerhans cells

Recently, it has been demonstrated that the skin-infiltrating T cells express cutaneous lymphocyte-associated antigen, which is the ligand of E-selectin or endothelial-leukocyte adhesion molecule, suggesting that cutaneous lymphocyte-associated antigen functions as the homing receptor of the skin infiltrating T cells. In contrast, the mechanism for the migration of Langerhans cells from the bone marrow to the skin has not been clarified. Sialyl LewisX acts as a ligand for endothelial-leukocyte adhesion molecule and granule membrane protein 140. We examined the expression of sialyl LewisX in epidermal dendritic cells in human skin. Two-color immunofluorescence study on an epidermal sheet revealed that human leukocyte antigen DR+ or CD1a+ epidermal dendritic cells were partially sialyl LewisX+, although all of the sialyl LewisX+ dendritic cells were human leukocyte antigen DR+ and CD1a+. Further analysis of these dendritic cells by flow cytometry demonstrated that most of the human leukocyte antigen DR+ and CD1a+ epidermal cells expressed sialyl LewisX, although the magnitude of its expression was more variable than that of CD1a expression, and that some of human leukocyte antigen DR+ cells were clearly sialyl LewisX-. Immunoperoxidase study of normal skin showed the presence of sialyl LewisX+ dendritic cells not only in the epidermis but also in the upper dermis. These data demonstrating the heterogeneity of the expression of sialyl LewisX by epidermal Langerhans cells suggest their possible relationship to the stage of maturation as well as to the migration of Langerhans cells from the bone marrow to the skin.

Immunohistochemical study of cell proliferation and differentiation in epidermis of mice after administration of cholera toxin

Cholera toxin causes reversible epidermal hyperplasia. We observed maximal thickness of the epidermis on the fourth day after treatment and a return to pretreatment values by day 7. The increase in thickness occurred in the basal and intermediate layers, with these layers becoming two to three times thicker than those of normal epidermis. The time sequence of epidermal proliferation was studied using bromodeoxyuridine (BrdU) labelling. We observed a maximum number of labelled basal cells within the first 24 h. Only a few cells were labelled 7 days after toxin injection. Griffonia simplicifolia-IB4 (GSA-IB4), Ulex europaeus-I (UEA-I) and Griffonia simplicifolia-II (GSA-II) lectins were used for the analysis of epidermal cell differentiation in the tissue sections. To study keratinocyte differentiation, further immunological staining was performed using two anticytokeratin antibodies, PKK2 and PKK3 mouse monoclonal antibodies. From the immunocytochemical results, we conclude that synchronous differentiation of the epidermis occurs after cholera toxin administration.

Distribution of cellular carbohydrate moieties in human dysontogenetic brain tumors, especially in craniopharyngioma and epidermoid/dermoid

Cellular carbohydrate moieties of 65 human dysonotogenetic brain tumors (craniopharyngioma, epidermoid/dermoid, Rathke cleft cyst, germinoma and non-germinomatous germ-cell tumors) and 60 common brain tumors (glioma, meningioma, neurinoma and pituitary adenoma) were investigated histochemically using sections from Ulex europaeus (UEA-1), Dolichos biflorus (DBA), peanut (PNA) and soybean (SBA), and with anti-blood group A and LewisY (LeyY) antibodies. In craniopharyngiomas and epidermoid/dermoids, it was found that PNA and SBA binding sites existed in suprabasal cells of the epithelium, and that antigen of either blood group A or H (demonstrable by UEA-1) existed in more differentiated epithelial cells compared to the results reported in normal human skin epidermis. Rathke cleft cysts were stained with PNA or SBA, and two out of three Rathke cleft cysts also expressed either H or A antigen. In addition, DBA binding sites, as well as LeY antigen, were frequently seen in craniopharyngiomas and Rathke cleft cysts, but they were entirely absent in the epithelium of epidermoid/dermoid. On the other hand, PNA and SBA reactivities was also found in common brain tumors, while blood group A, H and LeY antigens and DBA reactivity were almost absent in these tumors. These findings demonstrate that carbohydrate moieties such as those of blood group antigens reported to be found in human skin epidermis exist in a similar form in craniopharyngioma, epidermoid/dermoid and the Rathke cleft cyst. The identification of blood group A, H and LeY antigens and DBA reactivity in brain tumors seems to be considerably limited and specific.(ABSTRACT TRUNCATED AT 250 WORDS)

Differentiative changes in fucosyltransferase activity in newborn rat epidermal cells

An enzymatic activity catalyzing the transfer of L-fucose from GDP-L-fucose to a glycoprotein that is associated with the surfaces of the basal cells has been found in the membranous fraction of the cutaneous epidermis from the newborn rat. This fucosyltransferase which is located in the differentiated cells alters the acceptor glycoprotein's lectin-binding specificity from the Isolectin I-B4 of Griffonia simplicifolia (GS I-B4) to the Agglutinin I of Ulex europeus (UEA) and could be responsible for the same change in lectin-binding specificity that occurs as the epidermal basal cell differentiates. Another membraneous fucosyltransferase that can use asialofetuin--but not the GS I-B4-binding glycoprotein--as an acceptor, is also present in the membraneous fraction.

Expression of the L-fucose moiety on epidermal keratinocytes in psoriasis induced by the Koebner phenomenon: a sequential study

The expression of Ulex europaeus agglutinin (UEA I) binding sites on cell-surface glycoproteins has been used as a marker for terminal differentiation. Increased number of UEA I binding sites of L-fucose specificity have been demonstrated in psoriatic epidermis. The results of lectin-binding studies in a series of biopsies taken sequentially (0 min, 5 min, 24 h, 7 days and 8 weeks) after tape-stripping of uninvolved skin in 12 psoriatic patients (three of whom were taking diltiazem, a calcium blocker at the time of the study) and six controls are presented. UEA I binding sites, which were expressed on the granular layer and upper layers of the stratum spinosum of pre-tape stripped uninvolved skin in psoriatic individuals, were progressively more numerous, with the expression of the L-fucose moiety on the lower stratum spinosum keratinocytes in the 7-day post-tape-stripping biopsies and 8-week biopsies, correlating with a moderate and marked increase in the proliferative index, respectively. In the Koebner-negative and non-psoriatic individuals who failed to develop psoriasis after tape-stripping, the UEA I binding sites were not expressed on keratinocytes of the lower stratum spinosum in any of the biopsies, although a mild increase in the proliferative index was noted in the 7-day biopsies. Our data suggest that the increased commitment of keratinocytes to terminally differentiate may be involved in the psoriatic process.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of the L-Fucose Moiety on Infrainfundibular Follicular Keratinocytes of Terminal Follicles, Its Decreased Expression on Vellus and Indeterminate Follicles of Androgenetic Alopecia, and Re-Expression in Drug-Induced Hair Regrowth

The distribution of various glycoprotein molecules on the surface of follicular keratinocytes was studied with a panel of lectins with specificity for various sugar moieties on biopsy specimens from both bald/balding scalp and normal occipital scalp, of 23 patients with androgenetic alopecia as well as on biopsies of normal forearm skin of four patients. The most significant differences between bald and normal scalp biopsy were noted with Ulex europaeus agglutinin I (UEA I). We noted an increased (91.8% +/- 3.1; mean +/- SE) expression of UEA I binding sites on the infra-infundibular follicular keratinocytes in anagen terminal scalp hairs, compared to 28.5% +/- 5.2 in the indeterminate (anagen) hairs of balding scalps, and 23.2% +/- 6.3 in the anagen follicles of vellus fore-arm hairs. By contrast, the telogen hairs demonstrated minimal UEA I staining: 4.0% +/- 0.8, mean +/- SE in telogen scalp hairs, 1.8% +/- 0.5 in telogen hairs of balding scalps (0% in completely bald scalps, in which all the hairs were in the telogen phase), and 1.9% +/- 0.2 in telogen forearm hairs. The percentage of UEA I staining correlated with the length of the infra-infundibular follicles in all cases studied. In three cases of hair regrowth after hair growth promotors, the UEA I staining increased to 80.6% +/- 6.1 in anagen hairs and correlated with increased length of infra-infundibular follicles. Our data indicate that there are 1) marked differences between anagen and telogen follicles in UEA I binding to infra-infundibular follicular keratinocytes; 2) the percentage of UEA I staining reflects the size (length) of the infra-infundibular hair follicle; and 3) the anagen follicles of balding scalps (indeterminate hairs) show UEA I staining resembling that exhibited by anagen follicles of vellus hairs.

Histochemical and cytochemical localization of blood group antigens

The oligosaccharide structures of blood group antigens are not the primary gene products; they are constructed in a stepwise manner by adding particular sugar to precursor oligosaccharides via several glycosyltransferases coded for by different blood group genes (Watkins 1966, 1978, 1980). Consequently, final profiles of antigens expressed in each cell type are influenced by many different factors such as the intrinsic composition of glycosyltransferase species which are defined by the genotype of the individuals, relative activity or amount of these enzymes (repression, derepression or induction of the enzymes), competition between enzymes with overlapping substrate specificity, the organization of the enzymes in membranes, utilizability of precursors and specific substrate sugars, and the activity level of degradating enzymes. Changes in the antigen profiles during maturation, differentiation and malignant transformation are thought to be intimately related to the variability of these factors. Although great importance attaches to histo- and cytochemical information on the distribution and levels of glycosyltransferases and messenger RNA corresponding to the relevant enzyme, detailed and precise localization of the blood group antigens and their variants is the base line for analyzing these complex factors. On the basis of individual genotype and histochemical findings about the antigen distribution and the interrelationship between cells and cellular components producing different antigenic structures (cellular and subcellular mosaicism), we can deduce precursor oligosaccharide levels as well as the status of gene activation and its primary product, glycosyltransferases. Thus, these findings are a prerequisite for further analysis at the molecular genetic level. As emphasized in this article, lectin staining or immunostaining methods with MAbs combined with glycosidase digestion procedures are powerful tools for in situ analysis of carbohydrate structures in histochemical systems. Although in some cases valuable results have been obtained by applying the technique, our knowledge concerning the distribution of complex carbohydrate structures is still far from satisfactory. Along with well defined MAbs and lectins, the key to developing our methods further is successful introduction of glycosidases, in particular, endoglycosidases since these reagents are indispensable for analyzing the inner core structures and glycoconjugate species of the blood group antigens. Application of these techniques at the ultrastructural level is an alluring possibility, even though many difficulties must be overcome. Although their functional roles have not yet been determined, a diverse array of macromolecules is known to be decorated with blood group-related antigens.(ABSTRACT TRUNCATED AT 400 WORDS)

Cohesion and desquamation of epidermal stratum corneum

This article attempts to provide a comprehensive review on the roles of various classes of molecules in the cohesion and desquamation of the stratum corneum. In the first part of this monograph we review the field of epidermal differentiation in vivo and vitro, describing the expression and functions of a number of key structural molecules that characterize the process. In the second part we emphasize terminal differentiation and the biogenesis of the stratum corneum. The stratum corneum is a cell layer unique to fully differentiated squamous epithelia such as skin. While it is a dead stratum, it nevertheless is in a homeostatic process of continual shedding and renewal in synchrony with basal cell replication. It is also a degradative layer containing many proteinases and glycosidases in which a variety of intracellular and intercellular macromolecules are degraded. We highlight the molecules localized within the intercorneal matrix that are most likely to play a role in cohesion and desquamation, including: glycoproteins, lipids and enzymes. Because it is difficult to study the stratum corneum and desquamation in the native tissue, we discuss a number of model systems that have been used. The stratum corneum can be dispersed into single squames in different ways; these include mechanical dispersion as well as agents such as detergents and enzymes. The solubilized molecules and the structures remaining can then be studied as to their specific roles in desquamation. Using this approach it is possible to reconstitute multilayered structures that resemble a real stratum corneum. We have shown that glycoproteins play a key role in squame reaggregation and that this process can be modulated with amino sugars in a lectin-like fashion. Cohesion and desquamation can also be studied in tissue culture. Depending on the culture system, the extent of terminal differentiation and squame accumulation varies. Yet desquamation does not normally occur. It can be induced however by the inclusion of exogenous agents such as IFN-gamma which are found in the native epidermis but are absent in vitro. Modulation of desquamation by other exogenous agents is likely to yield further knowledge of how shedding occurs in vivo. Insight has also come from studies of scaling skin disorders. The glycoprotein and lipid profiles are altered in the stratum corneum in many diseases of aberrant terminal differentiation. A number of abnormalities in the levels of cytokines and growth factors have also been reported in the lesional tissue of such diseases.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparison of the Maclura pomifera lectin-binding glycoprotein in late fetal and adult rat lung

The lectin, Maclura pomifera agglutinin (MPA), binds to alpha-galactose residues of glycoproteins on the apical surface of type II alveolar cells. It has recently been shown to bind to macrophages. We isolated the cell surface glycoprotein, which binds the MPA lectin, from fetal and adult rat whole lung to determine if changes in this glycoprotein occur during development from fetal to adult life. The glycoprotein was purified from whole lung cell membranes by lectin affinity chromatography that resulted in 10(5)-fold enrichment. The MPA binding glycoproteins from both fetal and adult lung had the same apparent molecular weight of 170 kD as determined by sodium dodecylsulfate-polyacrylamide gel electrophoresis. Amino acid analysis revealed similar composition of the fetal and adult proteins. Two-dimensional peptide maps of the 170 kD proteins isolated from fetal and adult lung were also similar. These data indicate that the glycoprotein that binds MPA to lung cell membranes does not change during this stage of development. Our method for the isolation of this glycoprotein can be used for the generation of antibodies or other molecular probes for further study of this protein.

Glycoconjugates in the chinchilla tubotympanum

Various biotinylated lectins were used to characterize and semiquantitate glycoconjugate residues in the tubotympanum. Epithelial goblet cells were stained predominantly by WGA, LFA, SNA, RCA-I, Con-A, LCA, SBA, PHA-E, and UEA; this finding suggests they contain alpha-neuraminic acid, beta-galactose, alpha-mannose, N-acetyl alpha-galactosamine, and alpha-fucose. Glandular mucous cells were stained predominantly by WGA, LFA, SNA, and RCA-I; this finding suggests that they contain alpha-neuraminic acid and beta-galactose. The glandular serous cells were stained predominantly by Con-A, WGA, and LFA; this finding suggests that they produced alpha-mannose and alpha-neuraminic acid that represented serum-type glycoprotein. The positive staining of epithelial goblet cells and glandular mucous cells with PNA after neuraminidase digestion suggests that they produced mucin-type glycoproteins. The staining of the mucous blanket by WGA, LFA, SNA, RCA-I, LCA, PNA, SBA, PHA-E, and UEA suggests the presence of alpha-neuraminic acid, beta-galactose, N-acetyl alpha-galactosamine, and alpha-fucose. The epithelial cell (nonsecretory) surface was stained largely by WGA, LFA, SNA, RCA-I, Con-A, and LCA; this finding suggests the presence of alpha-neuraminic acid, beta-galactose, and alpha-mannose.

Properties of rat tracheal epithelial cells separated based on expression of cell surface alpha-galactosyl end groups

We used Griffonia (bandeiraea) simplicifolia I (GS I) lectin and flow cytometry to isolate subsets of rat tracheal epithelial cells based on the presence or absence of cell surface alpha-galactosyl end groups. These fractions were designated GS I-positive and -negative, respectively. Ninety-eight percent of the cells in the GS I-positive fraction expressed cell surface alpha-galactosyl end groups; 95% had immunocytochemically detectable keratin 14-related protein (a basal cell marker) and 98% lacked alcian blue-periodic acid-Schiff (AB-PAS)-stained cytoplasmic granules. More than 90% of the GS I-positive cells had a high nuclear-to-cytoplasm ratio, had tonofilaments, and lacked organelles characteristic of other differentiated cell types; they were thus classified as basal cells. In bioassays, the GS I-positive fraction had a colony-forming efficiency greater than or equal to that of native tracheal cell suspensions, and the cells were able to repopulate denuded tracheal grafts with ciliated, secretory, and basal cells. More than 99% of the cells in the GS I-negative fraction lacked cell surface alpha-galactosyl end groups, 98% did not stain for keratin 14-related protein, 54% had significant numbers of AB-PAS-stained cytoplasmic granules, and 16% were identified as ciliated cells. The GS I-negative fraction had a lower colony-forming efficiency than the GS I-positive fraction but, it too, was able to repopulate denuded tracheal grafts with a complete mucociliary epithelium. These results show that both GS I-positive and -negative cells had the potential to proliferate and differentiate into the major tracheal cell types.

The effect of PUVA therapy on glycoprotein biosynthesis in uninvolved psoriatic epidermis

Protein and N-linked glycoprotein biosynthesis was studied in the uninvolved epidermis of patients with psoriasis by the incorporation of radiolabelled leucine and mannose prior to and during PUVA treatment. Analysis of the polyacrylamide gel electrophoresis (PAGE) patterns of the 3[H]-labelled proteins and glycoproteins showed that the major changes in untreated uninvolved psoriatic epidermis compared to normal epidermis were: (a) a shift towards the synthesis of low-molecular-weight glycoproteins; (b) the absence of a 48-kDa peak labelled with mannose; (c) the appearance of 3[H]-mannose-labelled peaks at 40-36 kDa. PUVA treatment gradually changed the PAGE profile back more towards that expected for normal epidermis, with the reintroduction of a 52-48-kDa glycoprotein and reduction of the peaks in the 40-34-kDa region. This effect was dependent on uninterrupted treatment. The PUVA-treated PAGE profiles were compared to those expected in skin tumours (i.e. increased 3[H]-mannose-labelled peaks at 95 and 40-34 kDa with an absence of 62-kDa peaks). It appeared that these criteria were not seen generally as a result of PUVA treatment. However, the results indicate that tumour development may be possible if a patient responds to PUVA treatment by showing an increased peak at 95 and 40-34 kDa in association with a loss of an 3[H]-mannose-labelled peak at 62 kDa.

A comparison of glycoprotein biosynthesis in benign and malignant squamous epithelioma and normal epidermis

Protein and N-linked glycoprotein biosynthesis was studied in histologically verified normal epidermis, actinic keratoses, keratoacanthoma, intra-epidermal carcinoma and squamous-cell carcinoma using polyacrylamide gel electrophoresis (PAGE). The PAGE profiles of 3[H]-leucine-labelled proteins and 3[H]-mannose-labelled glycoprotein from all disease states studied differed from each other and from normal epidermis. A large 3[H]-mannose-labelled glycoprotein region (band A) with a peak at 97-92 kDa appeared to indicate the presence of a relatively large proportion of basaloid cells in the tissue. An associated peak in the region of 78-74 kDa also appeared in normal epidermis and what appeared to be non-invasive lesions. The main region of change in all lesions corresponded to the 66-34-kDa region (bands B and C). The absence of a group of glycoproteins and proteins in the 62-58-kDa region appeared to be specific for invasive squamous-cell carcinoma. All tumours showed a peak at 38-34 kDa which was not present in normal epidermis. Actinic keratosis had a pattern similar to normal epidermis except that the peaks of band B tended towards the higher-molecular-weight end of the band than those in normal epidermis and peaks at 28-22 kDa were seen. The latter seemed to correspond to the presence of a high proportion of spinous cells in the tissue sample.

Glycoconjugates of the lateral prostate of the guinea pig: a lectin histochemical study

The present study examined the glycoconjugates of the lateral prostate using a battery of lectins. The results indicated that the secretory epithelium was rich in mannose (Man), N-acetylglucosamine (GlcNAc), galactose (Gal), N-acetylgalactosamine (GalNAc), and complex oligosaccharides. Con A (concanavalin A), LCA (Lens culinaris agglutinin), PSA (Pisum sativum agglutinin), WGA (wheat germ agglutinin), PWM (pokeweed mitogen), RCA-I (Racinus communis isolectin I), and PHA-P (Phaseolus vulgaris agglutinin-P) reacted intensely with both epithelia and stroma, while SBA (soybean agglutinin) and PNA (peanut agglutinin), which bind to terminal Gal, GalNAc, and Gal beta 1,3 GalNAc appeared to be specific to the secretory epithelium. SBA and PNA were useful as markers in the study of the secretory function of the prostate gland. The present study has shown that the Golgi apparatus of prostatic epithelial cells was rich in fucose (Fuc), oligomers of GlcNAc, Gal beta 1,3 GalNAc, Gal, and Man containing glycoconjugates, indicating that the gland was actively involved in glycosylation. The present study has also shown that LTA (Lotus tetragonolobus agglutinin) is a good marker for the epithelial Golgi. PNA also bound to the epithelial basement membrane and the connective tissue in the lamina propria. The present study has thus established, for the first time, the glycoconjugate patterns in the lateral prostate of the guinea pig.

Lectin soybean agglutinin: measurements in colonic epithelial cells of human subjects following supplemental dietary calcium

A biomarker of cell differentiation was analyzed in normal and abnormal colonic epithelial cells. Soybean agglutinin (SBA) lectin which binds to specific carbohydrate residues was studied in normal human colonic epithelial cells, in epithelial cells in transitional colonic mucosa adjacent to carcinomas, and in colonic carcinomas. Findings revealed that increased SBA binding occurred maximally in normal, well-differentiated colonic epithelial cells, and least in colonic carcinomas. Further quantitation of SBA lectin binding also was carried out before and after supplemental dietary calcium. Findings revealed that in subjects whose colonic crypt biopsies had normal SBA lectin binding before calcium supplementation, SBA remained unchanged after calcium supplementation. However, in subjects whose biopsies initially had reduced SBA binding, the SBA increased after calcium and became more characteristic of that observed in normal colonic epithelium. In subjects receiving calcium for less than 3 months, the increased SBA was not statistically significant; but when subjects received calcium for durations of 3 months or longer SBA lectin binding was significantly increased, changing towards that observed in normal mucosa containing greater numbers of well-differentiated colonic epithelial cells.

Lectin histochemistry on squamous metaplasia in different epithelial tumors of dogs

Biotinylated lectins and avidin-biotin-peroxidase complex were used to study the correlation between cellular glycoconjugates' expression and squamous maturation in normal canine skin and in various epithelial neoplasms. Normal skin tissue was obtained from five, male, random-source dogs, 5 to 7 years old. The tumors tested, selected from the files of our Department, were fifteen squamous cell carcinomas from different tissue origin, five hepatoid perianal gland adenocarcinomas with squamous metaplasia, and fourteen solid mammary carcinomas with and without histologic evidence of squamous metaplasia. Except for mammary gland carcinomas, all tumors had been surgically excised from male dogs. Intermediate filament aggregation of twelve solid mammary gland carcinomas were studied electron microscopically. The basal and the lower spinous cells in normal skin and the less differentiated cells in squamous cell carcinomas stained moderately with Griffonia simplicifolia agglutinin-I. Spinous and granular cell layers stained strongly with Phytolacca americana mitogen and Arachis hypogaea agglutinin. Both lectins stained well-differentiated cells in squamous cell carcinomas. The electron microscopic study carried out in solid carcinomas of mammary glands revealed some relationship between the presence of intracytoplasmic tonofibrils and the binding of Griffonia simplicifolia agglutinin-I and Phytolacca americana mitogen to the tumors tested. Our results suggest that the glycosylation pattern occurring during normal keratinocyte differentiation is conserved in squamous cell carcinomas and that Griffonia simplicifolia agglutinin-I and Phytolacca americana mitogen may represent useful tools in distinguishing poorly differentiated squamous cell carcinomas from other poorly differentiated mammary epithelial tumors.

Changes in glycoconjugates revealed by lectin staining in the developing airways of Syrian golden hamsters

Lectin binding was studied in the developing airways of Syrian golden hamsters on gestational days 11-16 (day 16 is the day of birth). The trachea and lungs were fixed in 4% formaldehyde-1% glutaraldehyde, 6% mercuric chloride-1% sodium acetate-0.1% glutaraldehyde, and 95% ethanol; embedded in paraffin; and stained with eight lectin-horseradish peroxidase conjugates: Triticum vulgare (WGA), Dolichos biflorus (DBA), Helix pomatia (HPA), Maclura pomifera (MPA), Griffonia simplicifolia I-B4 (GSA I-B4), Arachis hypogaea (PNA), Ulex europeus I (UEA I), and Limulus polyphemus (LPA). Each lectin yielded a characteristic staining pattern, which modulated throughout development. In general, changes in staining characteristics of the tracheal epithelium preceded similar changes in the lobar bronchus, bronchiole, and alveolus. In the case of UEA I, MPA, WGA, and HPA, staining increased with time uniformly over the luminal surface of all epithelial cells. However, in the case of PNA, GSA I-B4, and LPA, after the differentiation of ciliated and secretory cells, the apical surfaces of the ciliated cells stained more intensely than the apical surfaces of the secretory cells. Neuraminidase pretreatment enhanced PNA and GSA I-B4 staining in both cell types. In the case of PNA, these light microscopic observations were confirmed by ultrastructural study. Unlike the other lectins, the pattern of staining with DBA was unusual. Staining was moderate at first, then decreased (days 13 and 14), then increased at all airway levels. This study shows that different glycoconjugates modulate in airway epithelial cells throughout fetal development.

Glycoconjugate expression of cells of human anagen hair follicles during keratinization

Changes in the expression of glycoconjugates in cells of the inner root sheath (IRS) and outer root sheath (ORS) of human anagen hair follicles were investigated by lectin histochemistry. Concanavalin A (Con A) and Ricinus communis (RCA-I) stained hair follicle cells regardless of their differentiation stages. In IRS, Ulex europeaus-I (UEA-I) bound to the surface of the cells as soon as they were morphologically defined, and Glycine max (SBA) stained as their differentiation progressed. Innermost (IM) cells of ORS layers were reactive with UEA-I at the stage where Henle's cells were keratinized, while the reactivity of UEA-I was lost at the site of the completion of IRS keratinization where SBA reaction was detected. Staining of both UEA-I and SBA was prominent in other ORS cells at the levels where SBA binding in IM cells became strong. The staining intensity increased up to the position of the follicular isthmus. In addition, a sugar residue recognized by Dolichos biflorus (DBA) was detected in differentiated cells of ORS. In contrast, the DBA reaction was not found at all in cells of IRS, infundibulum, and epidermis. These findings identified a complexity of carbohydrate metabolism in the cells of different layers at various stages of keratinization. IM cells differentiate independently from other ORS cells but seem responsive to the degree of IRS keratinization. All ORS cells possess a unique sugar moiety not found in other keratinocytes either in the hair or epidermis.

Lectin cytochemistry reveals differences between hamster trachea and bronchus in the composition of epithelial surface glycoconjugates and in the response of secretory cells to neutrophil elastase

Hamsters exposed to an intratracheal instillation of human neutrophil elastase (HNE) accumulate an abnormally high number of secretory granules in bronchial but not tracheal epithelial cells. We employed lectin cytochemistry to investigate possible differences in the epithelial cell surface glycoconjugate layer in trachea compared to bronchus which might explain the regional dissimilarity in response to HNE. Portions of glutaraldehyde-fixed trachea and bronchi were incubated in one of several ferritin-labeled lectins prior to embedding for transmission electron microscopy. Lectins from Ricinus communis, Helix pomatia, and Triticum vulgaris bound to the surface of tracheal secretory cells in moderate to profuse amounts, while most bronchial secretory cells showed little or no label with these lectins. Gold-labeled Helix pomatia agglutinin (HPA), a lectin specific for secretory cells, showed a decrease in surface binding to all tracheal secretory cell types within 2 h of HNE instillation, compared to saline controls. In contrast, the majority of bronchial secretory cells showed an HNE-induced increase in surface label from extremely low levels in saline controls. The low levels of lectin binding to bronchial cells, in contrast to the trachea, may indicate the lack of a protective surface glycoconjugate coat, thus explaining the vulnerability of these cells to HNE. The rise in number of accessible HPA binding sites on the surface of bronchial secretory cells exposed to HNE may represent an important event in the pathologic accumulation of secretory granules by these cells.

Phenotypic characterization of normal and neoplastic canine endothelial cells by lectin histochemistry

Cell surface glycoconjugate expression of endothelial cells in canine cutaneous hemangiomas and hemangiosarcomas was compared to normal cutaneous endothelial cells using eight different lectins (with and without neuraminidase pretreatment) in an indirect immunoperoxidase technique. Direct comparison of lectin binding pattern of neoplastic endothelial cells with adjacent normal endothelial cells revealed minor changes in the binding intensity of several lectins (enhanced: Wheat germ agglutinin [WGA]; reduced: Griffonia simplicifolia-I [GS-I], Ricinus communis agglutinin-I [RCA-I], Soybean agglutinin after neuraminidase pretreatment [Neu-SBA], and Wheat germ agglutinin after neuraminidase treatment [Neu-WGA]). Neoplastic endothelial cells in some tumors exhibited varying binding of Ulex europaeus agglutinin-I (UEA-I; not binding to normal canine endothelial cells) and no Soybean agglutinin (SBA) binding (variably binding to normal endothelial cells in small cutaneous vessels). Lectin binding of neoplastic cells was rather heterogenous within one tumor compared to the uniform binding pattern of normal endothelial cells. These lectin binding studies demonstrate the phenotypic heterogeneity of neoplastic endothelial cells, indicating changes of cell surface glycosylation during neoplastic transformation.

Cell surface glycosylation patterns in psoriasis

Cell surface carbohydrates are excellent markers of cellular differentiation and maturation processes due to their great structural and antigenic diversity as well as their known biosynthetic precursor/product relationships. Using a panel of monoclonal antibodies with well-defined carbohydrate specificities we have studied the expression of biosynthetically related antigens in normal and psoriatic skin. Two "families" of carbohydrate structures were investigated. One series of structures based on N-acetyllactosamine chains (type 2 chain: N-acetyllactosamine and fucosylated derivates hereof of H, Lex, Ley and sialyl-Lex) and another based on the simple mucin type core structures (type 3 chain: Tn, T and sialylated derivates hereof as well as the fucosylated derivative, H). Previously we have found these carbohydrate structures define distinct cell layers in stratified squamous epithelia of mucosa of the cheek, esophagus and uterine cervix. In normal and uninvolved epidermis, N-acetyllactosamine and T carbohydrates were found in the spinous cell layer, whereas the fucosylated derivates, H structures, were found in the granular cell layers above. The fucosylated and sialylated derivate of N-acetyllactosamine, sialylated Lex, had the same distribution as N-acetyllactosamine and T structures. This sequential expression of carbohydrates is similar to our previous findings in mucosa. However, in contrast to mucosa, normal skin basal cells did not label. The glycosylation pattern in psoriatic epithelium was changed in two ways. 1) Some carbohydrates (types 2 and 3 chain H and T) were expressed at an earlier stage of cell maturation. 2) The biosynthetic precursors to T structures, Tn and sialyl-Tn, which are not expressed in normal skin, and are often considered cancer-associated antigens, appeared in psoriatic skin. The Tn-antigen was expressed on basal and lower spinous cells, whereas the sialyl-Tn was only found on basal cells above the dermal papillae. The findings in the present work support previous studies of changes in cell surface glycosylation in psoriatic epidermis and demonstrate the appearance of tumor-associated antigens in highly proliferative, but benign, stratified epithelium.

Dolichos biflorus agglutinin (DBA) reveals a similar basal cell differentiation in normal and psoriatic epidermis

Binding of N-acetyl galactosamine (GalNAc)-specific Dolichos biflorus agglutinin (DBA) conjugates to frozen sections of normal epidermis and of psoriatic uninvolved and lesional skin was studied in fluorescence microscopy. The DBA conjugates bound only to single basal cell layer in normal and uninvolved psoriatic epidermis from patients with different blood group status. In the lesional area of psoriatic skin a similar reaction with a single basal cell layer was revealed. Other lectin-conjugates applied, presenting also GalNAc specificity, reacted with most cell layers of normal and both uninvolved and lesional psoriatic epidermis and gave an attenuated reaction with the middle epidermal layers. The results show that the basal cell characteristics are confined only to the cells along the basal membrane also in psoriatic epidermis, although cells in three lowest layers may be able to proliferate.

Dynamic changes of cell-surface glycoconjugates in human palmar epidermis following friction-blisters

Damage and repair of cell-surface glycoconjugates were examined in human palmar skin following friction-blister injury, using biotinylated lectins and the avidin-biotin complex method. In normal skin, concanavalin A, Ricinus communis, and Triticum vulgaris bound to the surface of cells from the basal layer to the granular layer. After injury, binding of concanavalin A was absent in the plasma membrane, but appeared in the cytoplasm at perinuclear sites. The surface reaction was recovered in basal and spinous cells, but not in granular cells, when cell maturation began at 5 days after injury. In contrast, binding of Ricinus communis and Triticum vulgaris was, in general, much more resistant to tissue damage. Even in some cells, where the surface staining became obscure at an early period, a normal staining pattern reappeared by 6 h after injury. Staining of Ulex europeus I and Glycine max, detected on the surface of upper spinous and granular cells in normal skin, disappeared immediately after the injury, but recovered quickly on the surfaces of the differentiated cells. These findings suggest that at least 2 oligosaccharide sequences, one binding with concanavalin A, and the other with Ricinus communis and Triticum vulgaris, may exist on epidermal cells. Addition of terminal carbohydrates, detectable with binding of Ulex europeus I and Glycine max, appears to occur on the Ricinus communis I and Triticum vulgaris-bound oligosaccharide chain.

Lectin binding patterns in squamous epithelium in experimentally induced hamster buccal pouch carcinoma

The distribution pattern of certain monosaccharides in the epithelial cells of the hamster buccal pouch was studied during carcinoma development induced by 9,10-dimethyl-1,2-benzathrancene (DMBA). An avidin-biotin-peroxidase complex (ABC) immunohistochemical technique with high affinity biotinylated lectins was employed to identify monosaccharides. Lectins used in this experiment included Concanavalin A (Con A), for identifying mannose or glucose, Ricinus communis agglutinin I(RCA-I), for identifying galactose, and Ulex europaeus agglutinin I(UEA-I), for identifying fucose. The results show that in normal buccal pouch epithelial cells, fuctose or galactose were concentrated predominantly on the cellular membrane, while mannose and glucose were distributed in the cytoplasm. In the epithelial cells undergoing neoplastic transformation induced by DMBA, most cells showed decreased staining of the above-mentioned monosaccharides, while in other areas the cells were heavily stained. However, the most striking change which occurred was that galactose and fucose shifted from the cellular membrane to the intracytoplasmic area during the malignant transformation. Thus, the changes of anatomic location and intensity of staining of monosaccharides in the buccal pouch epithelium may be used as a criteria for early histochemical diagnosis of malignant transformation.

A type VI collagen-related glycopolypeptide is the major concanavalin A-binding component in pig skin

The major concanavalin A-binding component in urea/deoxycholate/mercaptoethanol extracts of pig skin was a collagenous disulphide-cross-linked glycopolypeptide with an apparent molecular mass of 150 kDa and a pI of 5.5. Antiserum against the electrophoretically purified glycopolypeptide gave strong dermal staining similar to that seen with fluorescent concanavalin A. Immunocytochemical labelling showed prominent labelling of 3-4 nm dermal microfilaments, particularly those associated with dermal blood vessels and mast cells. Immunoblotting with authentic antiserum indicated that the major skin glycopolypeptide was probably identical with collagen-like glycoprotein, the tissue form of the alpha 1/alpha 2 subunits of type VI collagen. This was confirmed by immunoblotting of authentic type VI collagen from pepsin-treated pig skin. Immunoblotting, metabolic labelling with [3H]glucosamine and immune precipitation showed that an immunoreactive collagenous glycopolypeptide was synthesized and secreted by cultured pig skin fibroblasts. The results suggest that type VI collagen is the major concanavalin A-binding component in pig skin.

Sequential expression of carbohydrate antigens with precursor-product relation characterizes cellular maturation in stratified squamous epithelium

Cell surface carbohydrates are excellent markers for cellular differentiation and maturation due to great structural and antigenic diversity and to known precursor/product relations. Several blood group related carbohydrate antigens were analyzed in human labial stratified non-keratinized epithelium from 16 healthy individuals by immunohistology using monoclonal antibodies. The expression of these antigens was correlated with erythrocyte phenotype and saliva secretor status. Three distinct compartments of the epithelium were found and defined by the sequential expression of derivatives of Type 2 chain structures: lower, confined to basal cell layers (N-acetyllactosamine), middle, to parabasal cell layers (H) and upper, to spinous cell layers (Le(y)/Le(x)). Although the antigens are related to blood group antigens they are largely expressed independently of the ABO, Lewis and secretor types, and may therefore serve as "universal" markers in differentiation studies of normal and pathological epithelium.

Histocytochemistry of glycoconjugates in tonsillar tissues

Glycoproteins in palatine tonsillar epithelium were examined histochemically using seven different kinds of lectins to elucidate their functional morphology. UEA-I and WGA affinities, which might be altered due to an inflammatory reaction of the stroma, were detected selectively in the epithelial cell surface. Reacting products of SBA and GS-II were observed characteristically in the spinous and granular layers. No PNA, BPA and DBA activities were found in the tonsillar epithelium. These results suggest that carbohydrates on cell membranes might be changed according to the epithelial cell differentiation and some factors from the stroma.

Distribution and changes of glycoconjugates in rat colonic mucosa during development. A histochemical study using lectins

A study was made of the modifications of glycoconjugates in rat colonic mucosa during development. Sections of the caecum, and proximal and distal portions of the colon from Sprague Dawley rats at different stages of development (embryos, fetuses, suckling, weaning and adult rats) were examined. The sections were incubated with a battery of eight fluoresceinated lectins: DBA, SBA, WGA, LFA, PNA, GS-I, UEA-I and Con A. Some sections were treated with neuraminidase, and others were submitted to sequential saponification-neuraminidase treatment prior to incubation with the lectin (WGA, PNA or LFA). The intensity of the fluorescence was evaluated and graded from absent (-) to very positive (4+). Gradual and progressive changes were seen in colonic glycoconjugates during development. These changes revealed a unique developmental pattern for each lectin, which was independent for each cellular compartment (goblet cells, luminal surface and supranuclear region). Local and regional differences, observed between the different colonic sections, were already present from early stages of development. Moreover, our study showed that for several glycoconjugates, the differentiation process in colonic mucosa began in the distal region and continued through to the proximal region, the former being the first to reach the adult pattern. In the caecum, some lectins maintained a fetal pattern throughout all the periods of development up to the adult stage.

Differential effects of retinoic acid on the in vitro growth and cell-surface glycoconjugates of 2 human head and neck squamous-cell carcinomas

As a part of an assessment of the potential use of retinoids in preventive and adjuvant treatment of HNSCC, we examined the effects of beta-all-trans retinoic acid (RA) on the growth and cell-surface glycoconjugates of 2 HNSCC cell lines. These lines, designated 1483 and 183A, were established from an untreated patient with a well-differentiated SCC of the retromolar trigone and one with a poorly differentiated SCC of the tonsil. Whereas the 1483 cells were sensitive to RA in that their anchorage-dependent growth, their colony growth on solid substratum, and their anchorage-independent growth in semi-solid agarose gel were all inhibited in a dose-dependent fashion by RA concentrations in the range between 1 nM and 10 microM, the 183A cells were not inhibited by RA. Their anchorage-dependent growth and colony formation were stimulated by RA, whereas their anchorage-dependent colony formation was not altered. Cell-surface glycoconjugates were modulated by RA in the sensitive 1483 cells but not in the 183A cells. Treatment of the 1483 cells resulted in a large increase in the cell-surface labelling of high-molecular-weight (Mr greater than 400,000) galactoglycoconjugates and sialoglycoconjugates, as well as an Mr 280,000 sialoglycoconjugate. Glycoconjugates with similar electrophoretic mobilities in polyacrylamide gels were labelled intensely on the surface of the 183A cells even before RA treatment and only minor changes were noticed in their labelling after treatment. These results demonstrate that RA can exert different effects on different HNSCC lines, and suggest that correlations might exist between responsiveness to RA and the stage of differentiation of the HNSCC, and between modulation of cell growth and enhancement of cell-surface glycoconjugate glycosylation by RA.

Relationship between cell differentiation and binding of fluorescein isothiocyanate (FITC)-conjugated insulin of keratinocytes in culture

Basal-type keratinocytes, isolated from newborn rat skin and separated on Percoll density gradients, proliferate in low (0.1 mM) calcium medium and, after raising the calcium level to normal (1.96 mM), stratify. Cells in the low calcium culture do not have extensive cell-cell connections, as seen with fluorescein isothiocyanate (FITC)-conjugated insulin. Fluorescein isothiocyanate-conjugated concanavalin A and Griffonia simplicifolia isolectin B4, but not peanut agglutinin (PNA), fluorescently label these cells. In 3-day-old low calcium cultures, within 2 h after raising the calcium of the medium to the normal level, intense binding of PNA to cells appears and neighboring cells are connected through bundles of filaments that are fluorescently labeled by FITC-insulin. After 2 days in normal calcium medium, the cultures exhibit relatively smooth, straightlined, cell boundaries that are labeled by FITC-insulin and cell boundaries and intracellular granules that are stained by hematoxylin. One day later, similar cell boundaries are present, but they are not significantly decorated by FITC-insulin and, under phase contrast microscopy, are dark. Free FITC gives labeling patterns similar to those given by FITC-insulin, but the FITC labeling is blocked by mercaptoethanol and dithiothreitol in contrast to FITC-insulin binding. The present results suggest the insulin moiety is involved in the labeling by FITC-insulin and the labeling is chronologically related to the stage of cell differentiation.

Changes in lectin binding by differentiating cutaneous keratinocytes from the newborn rat

Surface glycoconjugates of cells from the basal layer of the skin of the newborn rat bind the isolectin I-B4 from Griffonia simplicifolia (GS I-B4) (alpha-D-galactosyl specificity). Surface glycoconjugates of the differentiated cells from the spinous and lower granular layers bind Ulex europeus agglutinin I (UEA) (alpha-L-fucosyl specificity). The change from GS I-B4 binding to UEA binding was studied in rat keratinocytes that were cultured as a monolayer in low-calcium medium until confluence, and then induced to stratify and terminally differentiate by raising the calcium concentration of the medium. The cells in the monolayer had basal cell morphology and exhibited surface binding of GS I-B4. However, at confluence, 30-40% of these cells also showed surface binding of UEA. There was an increase with time in the number of cells which bound both GS I-B4 and UEA. Raising the calcium concentration of the medium resulted in an increase in UEA binding. Cells of the upper layers of the stratifying cultures showed intense UEA binding but did not show any GS I-B4 binding. Double staining of frozen sections of newborn rat skin with fluorescein-conjugated GS I-B4 and rhodamine-conjugated UEA revealed that the surfaces of cells from the lower spinous layer bound both lectins. Thirty percent of the major glycoprotein fraction, that was isolated from the membranes of the epidermal cells of the newborn rat and was bound to an affinity column of UEA-Sepharose 4B, was also bound to an affinity column of GS I-B4-Sepharose 4B. These results indicate that surface glycoconjugates of rat keratinocytes differentiating in culture exhibit a change from GS I-B4 binding to UEA binding; the change in the cell surface glycoconjugates that results in the appearance of UEA binding, a feature of differentiated cells, occurs independently of stratification; and the change from GS I-B4 binding to UEA binding probably involves an "intermediate" glycoconjugate that binds both GS I-B4 and UEA and is found on the surface of cells from the lower spinous layer of the epidermis of the newborn rat.

Precocious development of lectin (Ulex europaeus agglutinin I) receptors in dome epithelium of gut-associated lymphoid tissues

Dome epithelium (DE), the tissue covering lymphoid domes of gut-associated lymphoid tissues, was examined in both adult and neonatal rabbit appendix or sacculus rotundus to determine if dome epithelial cells matured earlier than epithelial cells covering adjacent villi. The localization of well-differentiated epithelial cells in rabbit gut-associated lymphoid tissues (GALT) was accomplished histochemically by use of molecular probes: fluorescein isothiocyanate or horseradish peroxidase conjugates of Ulex europaeus agglutinin I (UEA), a lectin specific for terminal L-fucose molecules on certain glycoconjugates. The villus epithelial cells of newborn and 2-, 5-, or 10-day-old rabbits did not bind UEA, but between the twelfth and fifteenth days of postnatal life, UEA receptors were expressed by well-differentiated villus epithelial cells. In contrast to villus epithelium, DE in appendix and sacculus rotundus of neonatal rabbits expressed UEA receptors two days after birth, a feature that distinguished the DE of neonatal GALT for the next two weeks. In adult rabbits, UEA receptors were associated with dome epithelial cells extending from the mouths of glandular crypts to the upper domes; in contrast to the domes, UEA receptors were only present on well-differentiated epithelial cells at the villus tips. Results suggested that in neonatal rabbits most dome epithelial cells developed UEA receptors shortly after birth, reflecting precocious development of DE as compared to villus epithelium. In adult rabbit dome epithelium UEA receptors appeared on dome epithelial cells as they left the glandular crypts, representing accelerated epithelial maturation.

Glycoconjugate biosynthesis in human epidermis

Epidermal glycoconjugates synthesized by skin slices in media containing radiolabelled sugars were analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. A large proportion of the epidermal glycoconjugates were soluble in 10% (w/v) trichloroacetic acid. In addition to glycolipids and glycosaminoglycans, the acid-soluble fraction contained glycoproteins, a group of which (mol. wt. 70,000-160,000) were highly glycosylated and particularly rich in fucose. Analysis of the glycosaminoglycans by cellulose acetate electrophoresis combined with specific enzymic and nitrous acid degradation studies revealed that hyaluronic acid (73%) and heparan sulphate (18%) were the main components.

Cell surface and cytoskeletal changes associated with epidermal stratification and differentiation in organ cultures of embryonic human skin

Embryonic and fetal human epidermis differentiates in organ culture in an age dependent, though accelerated, manner. The older the specimen the less time is required for epidermal differentiation. Morphological markers of epidermal differentiation, including the different epidermal strata, keratohyalin granules, lamellar granules, and cornified cell envelopes, are formed in a manner that is faithful to development in vivo. The high molecular weight, "differentiation specific" (67 and 56.5 kDa) keratins are also expressed in these cultures, even in the absence of morphological evidence for keratinization. Unstratified, embryonic epidermis was found to stratify overnight in culture. The time course of cell surface changes, detected by lectin binding, and cytoskeletal changes, detected by expression of the high molecular weight keratins, was followed in these cultures. Peanut agglutinin (PNA) binding sites appeared overnight in culture coincidently with epidermal stratification while expression of the 67 and 56.5 kDa keratins was not detected until the third day of culture. The possible significance of these results is discussed.