The distribution of the glycosaminoglycans in the anatomic components of the lung and the changes in concentration of these macromolecules during development and aging

A Comprehensive Review of Electrospun Fibers, 3D-Printed Scaffolds, and Hydrogels for Cancer Therapies

Anticancer therapies and regenerative medicine are being developed to destroy tumor cells, as well as remodel, replace, and support injured organs and tissues. Nowadays, a suitable three-dimensional structure of the scaffold and the type of cells used are crucial for creating bio-inspired organs and tissues. The materials used in medicine are made of non-degradable and degradable biomaterials and can serve as drug carriers. Developing flexible and properly targeted drug carrier systems is crucial for tissue engineering, regenerative medicine, and novel cancer treatment strategies. This review is focused on presenting innovative biomaterials, i.e., electrospun nanofibers, 3D-printed scaffolds, and hydrogels as a novel approach for anticancer treatments which are still under development and awaiting thorough optimization.

Remodeling of the Aged and Emphysematous Lungs: Roles of Microenvironmental Cues

Aging is a slow process that affects all organs, and the lung is no exception. At the alveolar level, aging increases the airspace size with thicker and stiffer septal walls and straighter and thickened collagen and elastic fibers. This creates a microenvironment that interferes with the ability of cells in the parenchyma to maintain normal homeostasis and respond to injury. These changes also make the lung more susceptible to disease such as emphysema. Emphysema is characterized by slow but progressive remodeling of the deep alveolar regions that leads to airspace enlargement and increased but disorganized elastin and collagen deposition. This remodeling has been attributed to ongoing inflammation that involves inflammatory cells and the cytokines they produce. Cellular senescence, another consequence of aging, weakens the ability of cells to properly respond to injury, something that also occurs in emphysema. These factors conspire to make alveolar walls more prone to mechanical failure, which can set emphysema in motion by driving inflammation through immune stimulation by protein fragments. Both aging and emphysema are influenced by microenvironmental conditions such as local inflammation, chemical makeup, tissue stiffness, and mechanical stresses. Although aging and emphysema are not equivalent, they have the potential to influence each other in synergistic ways; aging sets up the conditions for emphysema to develop, while emphysema may accelerate cellular senescence and thus aging itself. This article focuses on the similarities and differences between the remodeled microenvironment of the aging and emphysematous lung, with special emphasis on the alveolar septal wall. © 2022 American Physiological Society. Compr Physiol 12:3559-3574, 2022.

The SARS-CoV-2 Entry Inhibition Mechanisms of Serine Protease Inhibitors, OM-85, Heparin and Soluble HS Might Be Linked to HS Attachment Sites

This article discusses the importance of D-xylose for fighting viruses (especially SARS-CoV-2) that use core proteins as receptors at the cell surface, by providing additional supporting facts that these viruses probably bind at HS/CS attachment sites (i.e., the hydroxyl groups of Ser/Thr residues of the core proteins intended to receive the D-xylose molecules to initiate the HS/CS chains). Essentially, the additional supporting facts, are: some anterior studies on the binding sites of exogenous heparin and soluble HS on the core proteins, the inhibition of the viral entry by pre-incubation of cells with heparin, and additionally, corroborating studies about the mechanism leading to type 2 diabetes during viral infection. We then discuss the mechanism by which serine protease inhibitors inhibit SARS-CoV-2 entry. The biosynthesis of heparan sulfate (HS), chondroitin sulfate (CS), dermatan sulfate (DS), and heparin (Hep) is initiated not only by D-xylose derived from uridine diphosphate (UDP)-xylose, but also bioactive D-xylose molecules, even in situations where cells were previously treated with GAG inhibitors. This property of D-xylose shown by previous anterior studies helped in the explanation of the mechanism leading to type 2 diabetes during SARS-CoV-2 infection. This explanation is completed here by a preliminary estimation of xyloside GAGs (HS/CS/DS/Hep) in the body, and with other previous studies helping to corroborate the mechanism by which the D-xylose exhibits its antiglycaemic properties and the mechanism leading to type 2 diabetes during SARS-CoV-2 infection. This paper also discusses the confirmatory studies of regarding the correlation between D-xylose and COVID-19 severity.

Isolation and Quantification of Glycosaminoglycans from Human Hair Shaft

Background

There is evidence that glycosaminoglycans (GAGs) are present in the hair shaft within the follicle but there are no studies regarding GAGs isolation and measurement in the human hair shaft over the scalp surface, it means, in the free hair shaft.

Objective

The purpose of our research was to isolate and measure the total GAGs from human free hair shaft.

Methods

Seventy-five healthy individuals participated in the study, 58 adults, men and women over the age of 50 and 17 children (aged 4~9). GAGs in hair samples, received from the parietal and the occipital areas, were isolated with 4 M guanidine HCl and measured by the uronic acid-carbazole reaction assay.

Results

GAGs concentration was significantly higher in the occipital area than in the parietal area, in all study groups. GAG levels from both areas were significantly higher in children than in adults. GAG levels were not associated with gender, hair color or type.

Conclusion

We report the presence of GAGs in the human free hair shaft and the correlation of hair GAG levels with the scalp area and participants' age.

Nebulized hypertonic saline containing hyaluronic acid improves tolerability in patients with cystic fibrosis and lung disease compared with nebulized hypertonic saline alone: a prospective, randomized, double-blind, controlled study

BACKGROUND

Hypertonic saline inhalation has been shown to be effective in patients with cystic fibrosis and lung disease. However, adverse events including marked airway narrowing are reported and a bronchodilator must be given before the administration of the product.

METHODS

We carried out a prospective, randomized, double-blind, parallel-group, controlled study of a hypertonic saline solution containing hyaluronic acid (Hyaneb) versus standard hypertonic saline therapy to assess whether the presence of hyaluronic acid would improve the tolerability of hypertonic saline.

RESULTS AND CONCLUSIONS

The results showed that nebulized Hyaneb was more effective in reducing the need for β(2) bronchodilators and caused a significant reduction in the incidence of adverse effects compared with nebulized hypertonic saline solution alone. Its safety profile indicates that Hyaneb can be used for the treatment of lung disease in cystic fibrosis.

Hyaluronic acid : perspectives in lung diseases

Hyaluronic acid (HA) is a non-sulphated glycosaminoglycan. It is a natural polymer characterised by a coiled linear chain in particularly well-hydrated configuration composed of repeating disaccaride units. In mammals, its molecular weight can be extremely wide, ranging from 20 to 4,000 kDa. High molecular mass forms are provided with anti-inflammatory properties. A unique characteristic of HA is hydration (up to 6,000 molecules water/molecule of HA) with a major role in the regulation of fluid balance in the interstitium, a fundamental activity on the amorphous colloidal matrix gluing connective cell and fibers, and many other biological functions including lubrication, solute transport and microcirculatory exchange. HA has been widely used in the treatment of eye, ear, joint and skin disorders; in the last 15 years HA has been also proposed successfully in the treatment of a number of lung diseases in vitro, experimental animals and humans. In particular, inhaled HA at relatively high molecular weight has been proven to prevent bronchoconstiction induced in asthmatics by direct and indirect challenges such as inhalation of methacholine, inhalation of ultrasonically nebulised distilled water, muscular exercise. More recently, in patients affected by chronic obstructive pulmonary diseases, we have demonstrated that repeated administrations of inhaled HA (daily, for 8 weeks) induce significant increase in bronchial patency as well as progressive lung deflation with decrease of residual volume. In conclusion there are elements that can let us state that is perhaps time to change the focus to connective tissue and extracellular matrix substances such as HA, in order to prevent and treat chronic lung diseases.

Hyaluronic acid improves "pleasantness" and tolerability of nebulized hypertonic saline in a cohort of patients with cystic fibrosis

INTRODUCTION

Inhaled hypertonic saline improves lung function and decreases pulmonary exacerbations in people with cystic fibrosis. However, side effects such as cough, narrowing of airways and saltiness cause intolerance of the therapy in 8% of patients. The aim of our study was to compare the effect of an inhaled solution of hyaluronic acid and hypertonic saline with hypertonic solution alone on safety and tolerability.

METHODS

A total of 20 patients with cystic fibrosis aged 6 years and over received a single treatment regimen of 7% hypertonic saline solution or hypertonic solution with 0.1% hyaluronate for 2 days nonconsecutively after a washout period in an open crossover study. Cough, throat irritation, and salty taste were evaluated by a modified ordinal score for assessing tolerability; "pleasantness" was evaluated by a five-level, Likert-type scale. Forced expiratory volume in 1 second was registered before and after the end of the saline inhalations.

RESULTS

All 20 patients (nine males, 11 females, mean age 13 years, range 8.9-17.7) completed the study. The inhaled solution of 0.1% hyaluronic acid and hypertonic saline significantly improved tolerability and pleasantness compared to hypertonic saline alone. No major adverse effects were observed. No difference was documented in pulmonary function tests between the two treatments.

CONCLUSION

Hyaluronic acid combined with hypertonic saline solution may contribute to improved adherence to hypertonic saline therapy. Further clinical trials are needed to confirm our findings. Considering the extraordinary versatility of hyaluronic acid in biological reactions, perspective studies could define its applicability to halting progression of lung disease in cystic fibrosis.

The 'sweet' and 'bitter' involvement of glycosaminoglycans in lung diseases: pharmacotherapeutic relevance

The extracellular matrix (ECM) plays a significant role in the structure and function of the lung. The ECM is a three-dimensional fibre mesh, comprised of various interconnected and intercalated macromolecules, among which are the glycosaminoglycans (GAG). GAG are long, linear and highly charged, heterogeneous polysaccharides that are composed of a variable number of repeating disaccharide units (macromolecular sugars) and most of them, as their name implies, have a sweet taste. In the lung, GAG support the structure of the interstitium, the subepithelial tissue and the bronchial walls, and are secreted in the airway secretions. Besides maintaining lung tissue structure, GAG also play an important role in lung function as they regulate hydration and water homeostasis, modulate the inflammatory response and influence lung tissue repair and remodelling. However, depending on their size and/or degree of sulphation, and their immobilization or solubilization in the ECM, specific GAG in the lung either live up to their sweet taste/name, supporting normal lung physiology, or they are associated to 'bitter' effects, related to lung pathology. The present review discusses the biological role of GAG in the lung as well as the involvement of these molecules in various respiratory diseases. Given the great structural diversity of GAG, understanding the changes in GAG expression that occur in lung diseases may lead to novel targets for pharmacological intervention in order to prevent and/or to treat a range of lung diseases.

Chondroitin sulfate in normal human plasma is modified depending on the age. Its evaluation in patients with pseudoxanthoma elasticum

Plasma chondroitin sulfate (CS) amount and charge density were determined in 45 healthy volunteers (control group), 45 pseudoxanthoma elasticum (PXE)-affected patients and 19 healthy carriers by using fluorophore-assisted carbohydrate electrophoresis (FACE) and HPLC equipped with postcolumn derivatization and fluorescence detection. The mean values of CS amount were 4.9+/-1.21 for volunteers, 4.7+/-1.40 for PXE subjects and 4.4+/-1.44 for the carriers. No significant differences were found for the three human subjects groups. On the contrary, by considering the age of normal volunteers, a significant increase of plasma CS amount was measured. In fact, the volunteers aging from 17 to 40 years (mean 32.1) showed a CS concentration of 4.3+/-1.30 while the group ranging from 50 to 74 years (mean 56.9) had a value of 5.6+/-1.16 with a significant increase of +30.2%. The same significant increase in CS plasma content with increasing age was measured for PXE-affected and healthy carriers group. Extracted plasma CS was evaluated for the main two unsaturated disaccharides, non-sulfated and 4-monosulfated, and the charge density determined. The mean values were 0.54+/-0.13 for volunteers, 0.60+/-0.15 for PXE subjects and 0.50+/-0.15 for the carriers. A significant increase of +11.1% was found between the PXE patients and healthy human group but no differences were calculated between the control group and the carriers. Furthermore, besides a CS amount, the volunteers aging from 17 to 40 years (mean 32.1) showed a charge density of 0.53+/-0.14 while the group ranging from 50 to 74 years (mean 56.9) had a value of 0.58+/-0.17 with a significant increase of +9.4%. The same trend was measured for the healthy carriers group. The CS charge density of PXE-affected subjects was found to increase significantly more than healthy controls depending on the age. In fact, the PXE patients aging from 10 to 40 years (mean 29.3) showed a charge density of 0.56+/-0.14 while the group ranging from 50 to 74 years (mean 58.6) had a value of 0.67+/-0.11 with a significant increase of +19.6%. Furthermore, the group of PXE-affected subjects ranging from 50 to 74 years (mean 58.6) showed a significant increase of 15.5% in comparison with the group matched for age (mean 56.9) of healthy volunteers.

Increased glycosaminoglycans in the urine of asthmatic children on inhaled corticosteroids

Increased extracellular matrix (ECM) deposition in the airway wall contributes to the airway remodeling in asthmatics. Glycosaminoglycans (GAGs) are polysaccharides attached to a protein core in order to form proteoglycans, a component of the ECM. In this study, we investigated the possible influence of long-term treatment with inhaled corticosteroids (ICS) on urinary GAGs levels of asthmatic children. Seventy asthmatic children (41 boys), aged 6.8-12.5 yr, participated in the study. About 44 were treated with inhaled budesonide via turbuhaler for 2-35 months (median 12 months) and 26 were on relief medications. About 30 healthy controls were also studied. GAGs were precipitated from early morning urine samples, collected, isolated and quantified using uronic acid-carbazole reaction and expressed as uronic acid (UA) in microg/g/Cr(u)/m2. Urinary GAGs values did not differ significantly between controls and asthmatics but significant differences were found between children on ICS and asthmatics on relief medications (p < 0.001). There was a positive correlation between the daily dose of inhaled budesonide and the urinary GAGs values (r = 0.32, p = 0.037) whereas a threshold distinguishing 'low' vs. 'high' doses of ICS was found to be at 300 microg/m2 per day with a significant difference in urinary GAGs secretion (p = 0.006). Our data show that urinary GAGs secretion is reduced in asthmatic children that used only relief medication but it is increased in those on long-term treatment with ICS. A dose dependent effect of ICS was also detected.

Hypoxia differentially enhances the effects of transforming growth factor-beta isoforms on the synthesis and secretion of glycosaminoglycans by human lung fibroblasts

Interstitial lung diseases associated with hypoxia, such as lung fibrosis, are characterized by enhanced production of transforming growth factor-beta (TGF-beta) and increased deposition of extracellular matrix (ECM) molecules, including glycosaminoglycans (GAGs). In this study, we investigated the effect of hypoxia (3% O(2)) on TGF-beta-induced GAG synthesis by primary human pulmonary fibroblasts, established from lung biopsies. Total GAG synthesis was assessed by the incorporation of [(3)H]glucosamine into GAGs associated with the cell layer (cells and ECM) or secreted in the medium. GAGs were isolated and purified by gel filtration, fractionated by electrophoresis on cellulose acetate membranes, and characterized using GAG-degrading enzymes. GAG molecules identified in the cell layer and the medium were: hyaluronic acid, and chondroitin, dermatan, and heparan sulfates. All TGF-beta isoforms time dependently induced [(3)H]glucosamine incorporation into GAGs of the cell layer or the medium. Characterization of individual GAG molecules indicated that this was attributed to dermatan and heparan sulfates in the cell layer and to hyaluronic acid and chondroitin and dermatan sulfates in the medium. Hypoxia enhanced the effect of all TGF-beta isoforms, particularly that of TGF-beta3, on the secretion of hyaluronic acid and chondroitin and dermatan sulfates. In the cell layer, hypoxia stimulated only the effect of TGF-beta2-induced [(3)H]glucosamine incorporation into GAGs. Our data indicate that hypoxia differentially enhances the effect of TGF-beta isoforms on the secretion and deposition of GAGs and may hasten ECM remodeling associated with the pathogenesis of lung fibrosis.

Neutrophil-mediated degradation of lung proteoglycans: stimulation by tumor necrosis factor-alpha in sputum of patients with bronchiectasis

Neutrophil-mediated degradation of bronchial matrix has been proposed as a pathogenetic factor in bronchiectasis. We hypothesize that neutrophils, found in abundance in the bronchial lumens of patients with bronchiectasis, are capable of degrading lung matrix proteoglycans and that proinflammatory mediators in bronchial secretions of these patients can enhance the degradative action of neutrophils. We used rat bronchoalveolar proteoglycans entrapped in polyacrylamide gel beads as a substrate for test incubations with neutrophils from healthy volunteers and sputum sol from patients with idiopathic bronchiectasis. Coincubations with specimens of sputum sol and neutrophils showed proteoglycan degradation indices (PDIs) in excess of the sum of indices due to incubation with either heat-inactivated sputum sol or heat-inactivated neutrophils, suggesting sputum stimulation of the neutrophil response. Mediation of this stimulation by tumor necrosis factor (TNF)-alpha was suggested because (1) indices for the coincubations correlated with sputum levels of TNF-alpha and (2) an anti-TNF-alpha antibody completely attenuated the sputum-stimulated effect. Furthermore, recombinant human TNF-alpha required accompanying sputum sol to exert an enhancing effect on neutrophil-mediated proteoglycan degradation. Because neutrophil-mediated proteoglycan degradation in the coincubations was inhibited largely (90%) by Eglin C and much less so (8% to 20%) by ethylenediamine tetraacetic acid, we conclude that serine proteases secreted by neutrophils were mainly responsible for degradation of proteoglycans in the model matrix and that the secretion was stimulated by TNF-alpha in the presence of cofactors in the bronchial secretions of patients with bronchiectasis.

Hypoxia modifies the effect of PDGF on glycosaminoglycan synthesis by primary human lung cells

Hypoxia, a consequence of interstitial lung diseases, may lead to secondary pulmonary hypertension and pulmonary vascular remodeling. Hypoxia induces activation and proliferation of lung cells and enhances the deposition of extracellular matrix including glycosaminoglycans (GAGs). To elucidate the cell biological mechanisms underlying the development of secondary pulmonary hypertension, we studied the effect of hypoxia on GAG synthesis by human lung cells. GAG synthesis was measured by incorporation of [(3)H]glucosamine; GAGs were isolated, purified, and characterized with GAG-degrading enzymes. Fibroblasts and vascular smooth muscle cells (VSMCs) synthesized hyaluronic acid, heparan sulfate, and chondroitin sulfates, whereas dermatan sulfate was found only in fibroblasts. Hypoxia did not influence the size or charge of the individual GAGs. However, hypoxia inhibited platelet-derived growth factor-induced [(3)H]glucosamine incorporation in secreted GAGs, especially hyaluronic acid, in VSMCs. In contrast, it stimulated GAG secretion, specifically heparan sulfate, by fibroblasts. Our results indicate that hypoxia induces modifications in GAG synthesis by human lung VSMCs and fibroblasts that may be correlated to pathophysiological manifestations in lung diseases causing hypoxia.

Iduronic acid-containing glycosaminoglycans on target cells are required for efficient respiratory syncytial virus infection

Respiratory syncytial virus (RSV) is an important human respiratory pathogen, particularly in infants. Glycosaminoglycans (GAGs) have been implicated in the initiation of RSV infection of cultured cells, but it is not clear what type of GAGs and GAG components are involved, whether the important GAGs are on the virus or the cell, or what the magnitude is of their contribution to infection. We constructed and rescued a recombinant green fluorescent protein (GFP)-expressing RSV (rgRSV) and used this virus to develop a sensitive system to assess and quantify infection by flow cytometry. Evaluation of a panel of mutant Chinese hamster ovary cell lines that are genetically deficient in various aspects of GAG synthesis showed that infection was reduced up to 80% depending on the type of GAG deficiency. Enzymatic removal of heparan sulfate and/or chondroitin sulfate from the surface of HEp-2 cells also reduced infection, and the removal of both reduced infection even further. Blocking experiments in which RSV was preincubated with various soluble GAGs revealed the relative blocking order of: heparin > heparan sulfate > chondroitin sulfate B. Iduronic acid is a component common to these GAGs. GAGs that do not contain iduronic acid, namely, chondroitin sulfate A and C and hyaluronic acid, did not inhibit infection. A role for iduronic acid-containing GAGs in RSV infection was confirmed by the ability of basic fibroblast growth factor to block infection, because basic fibroblast growth factor binds to GAGs containing iduronic acid. Pretreatment of cells with protamine sulfate, which binds and blocks GAGs, also reduced infection. In these examples, infection was reduced by pretreatment of the virus with soluble GAGs, pretreatment of the cells with GAG-binding molecules, pretreatment of the cells with GAG-destroying enzymes or in cells genetically deficient in GAGs. These results establish that the GAGs involved in RSV infection are present on the cell rather than on the virus particle. Thus, the presence of cell surface GAGs containing iduronic acid, like heparan sulfate and chondroitin sulfate B, is required for efficient RSV infection in cell culture.

The content and distribution of glycosaminoglycans in the ejaculates of normal and vasectomized men

The glycosaminoglycans (GAGs) of sperm and seminal plasma of normal men and seminal plasma of vasectomized individuals have been identified and quantified by two dimensional (2D) electrophoresis. The sperm contains predominantly CSC and HS as well as significant amounts of DS which achieves a high level in the sperm of the youngest man, while HA and LSC are either undetectable or present in small quantities. In normal seminal plasma, characteristically, DS is essentially lacking whereas CSC is the major GAG and HA and LSC account for relatively high percentages. Interestingly, in the ejaculates of vasectomized men the DS content is relatively prominent and the HA concentration varies widely. The oversulfated chondroitin sulfates CSD/CSE were detected in 7 of the 37 specimens. Their presence in a normal human body fluid is reported for the first time and the previous observation of the youthful DS/CSC switch is expanded to this study.

The glycosaminoglycan composition of the lung with acute and chronic pathology and in senescence

The content and distribution of GAGs in the anatomic structures of pathological (pneumoconiosis, pneumonia, pulmonary embolism) and senescent lungs have been measured. The total GAG content of the lung structures, except central bronchi is generally lower than normal in the pathological lungs. The GAG distribution in the pleura (DS predominant), central bronchi (C6S predominant), arteries, veins and 'total lung' is similar to the corresponding normal distribution. The other notable observations are: the concentration of HA in peripheral bronchi and alveoli is increased possibly in response to the high local concentration of coal dust; an age related GAG switch from DS in the arteries of the young to C6S in the arteries of the mature lung is confirmed; the arterial GAG content generally increases with age up to age 103 in the male; the arteries of a female smoker display the mature male pattern of GAG composition. The data suggest that gender, smoking and age, more than acute pathology, determine the GAG composition of the anatomic structures of the lung.

Effect of transforming growth factor beta on synthesis of glycosaminoglycans by human lung fibroblasts

The processes of lung growth, injury, and repair are characterized by alterations in fibroblast synthesis and interstitial distribution of extracellular matrix components. Transforming growth factor beta (TGF-beta), which is postulated to play a role in modulating lung repair, alters the distribution of several matrix components such as collagen and fibronectin. We studied the effect of TGF-beta on the synthesis and distribution of the various glycosaminoglycans (GAGs) and whether these effects may explain its role in lung repair. Human diploid lung fibroblasts (IMR-90) were exposed to various concentrations of TGF-beta (0-5 nM) for variable periods of time (0-18 h). Newly synthesized GAGs were labeled with either [3H]glucosamine or [35S]sulfate. Individual GAGs were separated by size exclusion chromatography after serial enzymatic and chemical digestions and quantitated using scintillation counting. There was a dose-dependent increase in total GAG synthesis with maximal levels detected after 6 h of exposure. This increase was noted in all individual GAG types measured and was observed in both the cell associated GAGs (cell-matrix fraction) as well as the GAGs released into the medium (medium fraction). In the cell-matrix fraction, TGF-beta increased the proportion of heparan sulfate that was membrane bound as well as the proportion of dermatan sulfate in the intracellular compartment. In the medium fraction, TGF-beta increased the proportion of hyaluronic acid, chondroitin sulfate and dermatan sulfate released. We conclude that the role of TGF-beta in lung growth and repair may be related to increased synthesis of GAGs by human lung fibroblasts as well as alterations in the distribution of individual GAGs.

Mechanisms of extracellular matrix proteoglycan degradation by human neutrophils

Alterations in proteoglycans (PG) located in the pulmonary interstitium may influence extracellular matrix (ECM) structure and assembly during the development of diseases in which increased numbers of neutrophils enter the lung. To evaluate potential mechanisms of PG degradation, neutrophils or purified neutrophil products were incubated with ECM that had been produced by cultured neonatal rat vascular smooth muscle cells (SMC) or lung fibroblasts (LF) and metabolically labeled with 35SO4. Matrix PG solubilization was expressed as a percentage of the spontaneous [35SO4]PG solubilization that occurred in the presence of buffer alone. Solubilization by unstimulated neutrophils was 105.8 +/- 3.1% (mean +/- SEM, n = 6) and 101.7 +/- 3.05 (n = 8) using ECM that had been produced by LF and SMC, respectively. Solubilization by neutrophils that had been stimulated with formyl-methionine-leucine-phenylalanine (FMLP) in the presence of cytochalasin B (CB) was 189.7 +/- 5.8% and 298.2 +/- 26.2% using ECM produced by LF and SMC, respectively. Matrix that had been produced by SMC was used to evaluate which neutrophil products were responsible for the degradation of PG. Addition of a specific inhibitor of neutrophil elastase (NE) to stimulated polymorphonuclear leukocytes (PMN) reduced PG solubilization by 88.3 +/- 4.8% (n = 8). Addition of an inhibitor of cathepsin G (CG), as well, did not further reduce PG degradation. Purified CG and myeloperoxidase solubilized significantly more PG, 125.8 +/- 6.2% (n = 9) and 143.2 +/- 8.1% (n = 6), respectively (P less than 0.01), than was solubilized spontaneously.(ABSTRACT TRUNCATED AT 250 WORDS)

Isolation of in vivo radiolabeled proteoglycans from rat lung

Sulfated macromolecules of rat lung tissue were labeled in vivo with 35SO4 and extracted with a solution of 7 M urea containing 0.4% Triton X-100. DEAE-Sephacel chromatography separated sulfated macromolecules into three pools. Pool I consisted of high-molecular-weight, low-density sulfated glycoprotein, probably of mucous secretion origin. Pool II contained a mixture of proteoheparan sulfate and proteodermatan sulfate, together with core protein-free heparan sulfate chains. Pool III was very heterogeneous; its resolution into at least four proteoglycan species was achieved by CsCl density gradient centrifugation. Those included two (high- and low-density) species of proteoheparan sulfate, high-density proteochondroitin sulfate, and medium-density (1.45 less than rho less than 1.55 g/ml) proteodermatan sulfate.

Transition from normal to hypersecretory bronchial mucus in a canine model of bronchitis: changes in yield and composition

Density-gradient analysis was used to follow the transition from normal to hypersecretory bronchial mucus in a model of bronchitis induced in dogs by chronic exposure to SO2 gas. Aspirates of saline bronchial lavage were obtained by fiberoptic bronchoscopy from dogs before, during a 6- to 9-month exposure period to SO2 gas, and during a recovery period of similar duration. Prior to SO2 exposure, aspirates from all animals had a low yield of nondialyzable macromolecules (15 +/- 6 mg/aspirate) and similar composition. Specifically, epithelial glycoprotein of typical buoyant density was not detected; rather a glycoconjugate of higher buoyant density with features of both proteoglycan and glycoprotein was identified. Neutral lipids were predominant with lesser amounts of phospholipids; no glycolipids were detected. During the SO2 exposure period, aspirates from five of the eight dogs contained components similar in buoyant density to human bronchitic glycoprotein. Glycoprotein isolated from the canine aspirates was similar to glycoprotein isolated from human chronic bronchitic sputum, having the same carbohydrate composition and range of oligosaccharide size. Further, during and after SO2 exposure some aspirates contained appreciable amounts of glycolipids. These data demonstrate substantial similarities in composition between normal human and canine mucus and in mucus isolated from dogs with chronic airway inflammation induced by repeated irritant exposure and from human patients with chronic bronchitis.

Developmental heterogeneity of mesenchymal glycosaminoglycans (GAG) distribution in chick embryo lung anlagen

The presence and distribution of mesenchymal components in the extracellular matrix during lung development in the chick embryo (from 5 1/2/6 to 18 incubation days) has been examined histochemically. Attention is focused mainly on glycosaminoglycans (GAG). Morphological reconstructions show three main stages: first (5 1/2/6-8 days), formation of 2nd-order branching; second (9-12 days), proliferation of parabronchi and third (from 13th day on), formation of air capillaries. In the first phase, hyaluronic acid (HA) prevails around the mesobronchus, but chondroitin sulfate (CS) dominates the 2nd-order branches. Basement membranes of 2nd-order branches are strongly positive for sulphated GAG. In the second phase, CSA increases in the ground substance of mesenchyme. This increase is irregular, being smaller in older areas (mesobronchus, branches of 2nd order) and larger in the more recent parabronchi, which extend into the lateral and dorsal areas of the rudiment. An increase in both sulfated GAG and glycoprotein (GP) occurs in basement membranes. In the third phase, GAGs are uniformly distributed in the mesenchymal septa and around the interlobular vascular network. This concentration decreases while the GP concentration increases. Basement membranes around every branch of the 1st, 2nd, and 3rd orders possess large quantities of GP. Mesenchymal GAG occurs in every stage of lung development, temporally correlating with the morphogenesis and differentiation of epithelium. Our results provide necessary information, which has not been available so far. Experimental studies specifically designed to clarify the developmental significance of such a heterogeneous distribution may be interpreted in the light of this information.

Characterization of proteoglycans synthesized by fetal rat lung type II pneumonocytes in vitro and the effects of cortisol

The synthesis of proteoglycans by primary cultures of 19-day gestation fetal rat lung Type II pneumonocytes was studied. The cells were grown in the presence of [3H]-glucosamine and/or [35S]-Na2SO4 and the radioactive label incorporated into proteoglycans was analyzed. Proteoglycans of high molecular weight (approximately 200 Kd) were isolated by gel permeation chromatography and contained both [3H] and [35S]. The glycosaminoglycan composition of the proteoglycans was determined by electrophoresis and autoradiography. The medium contained 65-80% of the labeled proteoglycans and was enriched for hyaluronate, with lesser amounts of the sulfated glycosaminoglycans (dermatan sulfate greater than heparan sulfate greater than chondroitin sulfate). The cell layers retained 20-35% of the labeled proteoglycans and was enriched for heparan sulfate, with lesser amounts of chondroitan sulfate greater than dermatan sulfate greater than hyaluronate. The synthesis of proteoglycans was time-dependent and was stimulated by increasing concentrations of fetal bovine serum. Cortisol inhibited proteoglycan synthesis, apparently by decreasing the availability of proteoglycan core-protein.

Profiling of carbohydrates, glycoproteins and glycolipids

Current chromatographic methods for the analysis of a variety of carbohydrate materials in body fluids and tissues have been reviewed, from the viewpoints of clean-up of samples, separation modes, methods for detection and quantification, and degree of convenience. This review also contains several tables, listing names of samples, methods of analysis, analytical conditions, and normal as well as pathological levels reported, from representative publications.

Myocardial chondroitin sulfates D and E in a case of acute carbon monoxide poisoning

The glycosaminoglycans of the myocardium of an individual who died of acute carbon monoxide poisoning were quantified by two-dimensional electrophoresis on cellulose acetate membranes. The total glycosaminoglycan content was found to be approximately twice the normal value. In contrast to the content of each glycosaminoglycan of the normal heart, the level of the chondroitin sulfates of this patient's myocardium was found to be markedly increased whereas that of hyaluronic acid was decreased and dermatan sulfate could not be detected. Further, this tissue contained significant amounts of keratan sulfate and an oversulfated dermatan sulfate, glycosaminoglycans not found in normal myocardium. Of particular interest was the presence of two unusual oversulfated chondroitin sulfates (chondroitin sulfates D and E).

Density gradient analysis of secretions produced in vitro by human and canine airway mucosa: identification of lipids and proteoglycans in such secretions

Human and canine airway mucosal explants synthesize and secrete high molecular weight glycoconjugates, incorporating 14C-glucosamine, a radioactive precursor to epithelial glycoprotein. Our examination of secretions produced by several individual specimens, however, did not reveal epithelial glycoprotein of typical buoyant density (1.5 g/ml in CsBr); only a high-density component with features of glycoprotein and proteoglycan. To provide sufficient material for characterization, secretions from several specimens of human and canine explants were separately pooled and subjected to DGU in CsBr. After removal of lipids and proteins, the glycoconjugates were recovered into five fractions of different density. 14C-glucosamine had been incorporated in all five fractions. Fractions 1-4 together accounted for 88% of the radiolabel but gas chromatography indicated that none of these contained epithelial glycoprotein. Their amino acid compositions were similar to those of proteoglycans and electrophoresis confirmed the presence of chondroitin sulfates A, B, C, heparan sulfate and hyaluronic acid. Sugars typical of epithelial glycoprotein were identified only in the glycoconjugate subfraction 5 of lowest density (and also lowest in yield) in which glycosaminoglycans were also identified. By addition of radioactive precursors, 14C acetate, 14C palmitate and 14C mevalonic acid to the culture medium and autoradiography of the secreted lipids we have shown that the tracheal explants actively synthesize lipids. Lipids accounted for a high proportion, almost half by weight, of the explant secretion. While neutral and phospholipids predominate, glycolipids were also identified.

Cell-cell matrix interactions in induced lung injury. II. X-irradiation mediated changes in specific basal laminar glycosaminoglycans

The thoraces of male LAF1 mice were irradiated at doses of 5, 9, or 13 Gy. The animals were killed at times of 1 hr, 1 day, 1 wk, 4 wks, and 12 wks postirradiation (PI). The lungs were removed, enzymatically or detergent digested, fixed with ruthenium red for demonstration of anionic sites, and processed for electron microscopy. Untreated (0 Gy, 0 time) and sham irradiated control groups were also processed. Sections of lungs were examined and changes in alveolar basal laminar anionic sites were quantitated. Changes in three groups of glycosaminoglycans (GAGs) were identified: chondroitin 4 and 6 sulfate-dermatan sulfate, hyaluronate, and other GAGs (principally heparan sulfate). At 1 hr PI, all groups showed a marked decrease in site number over controls, which continued to 1 wk. By 4 wks there was a marked relative increase in heparan sulfate containing sites for doses of 13 Gy and a moderate increase for the other doses. At 12 wks the level of heparan sulfate was considerably above normal for doses of 13 Gy and just above normal for the other doses. Chondroitin-dermatan sulfate had recovered by 12 wks for doses of 13 Gy, but was still subnormal for other doses; however, hyaluronate-containing sites recovered only slightly by 12 wks. The implications for this change on basal laminar permeability and the induction of fibrosis are discussed.

Staining of proteoglycans in mouse lung alveoli. II. Characterization of the Cuprolinic blue-positive, anionic sites

The nature of Cuprolinic Blue-positive anionic filaments in mouse lung alveoli has been characterized. The contrast of filaments in the alveolar basement membrane of type I epithelial cells was lost on treatment with nitrous acid and pronase (without prefixation). In contrast, neither neuraminidase, chondroitinase ABC or AC, nor Streptomyces hyaluronidase had any effect. Treatment with pronase (after prefixation) and 2.0 M MgCl2 (after prefixation) also had no effect, indicating that the filaments are heparan sulphate proteoglycans. The filaments in the alveolar basement membrane of type II epithelial cells and in the capillary basement membrane of the endothelial cells were also nitrous acid sensitive, but chondroitinase ABC-insensitive. A model in which the whole alveolus contains a single layer of heparan sulphate-containing proteoglycan monomers is proposed. Furthermore, the collagen fibril associated filaments remained unaffected after treatment with nitrous acid, neuraminidase or Streptomyces hyaluronidase, or after digestion with pronase (after prefixation) and treatment with 2.0 M MgCl2 (after prefixation). These filaments, however, could no longer be detected when digestion with chondroitinase ABC or pronase (without prefixation) was applied; chondroitinase AC treatment clearly affected the filaments, although they still were visible. These results indicate that the filaments are dermatan sulphate-containing proteoglycans. Some functional aspects of the proteoglycans are discussed.