Proteoglycan Research Articles

IL-10 Could Play a Role in the Interrelation between Diabetes Mellitus and Osteoarthritis.

The association between osteoarthritis (OA), obesity and metabolic syndrome suggests an interrelation between OA and diabetes mellitus (DM). Little is known about the role of anti-inflammatory cytokine interleukin (IL)-10 in the interrelation between OA and DM. Hence, the effects of IL-10 under hyperglycemia (HG) and hyperinsulinemia (HI) in human articular chondrocytes (hAC) and chondrosarcoma cell line Okayama University Medical School (OUMS)-27 were examined. HAC and OUMS-27, cultured in normoglycemic (NG) and HG conditions were stimulated with insulin and/or IL-10. Cell survival, metabolic activity, proliferation and extracellular matrix (ECM) synthesis were immunocytochemically examined. No significant differences in vitality of hAC neither in pure NG (NGw/o) nor HG (HGw/o) conditions were found. Applying HI and/or IL-10 in both conditions reduced significantly the vitality of hAC but not of OUMS-27. HG impaired significantly hAC metabolism. When combined with HI + IL-10 or IL-10 alone it decreased also significantly hAC proliferation compared to NGw/o. In OUMS-27 it induced only a trend of impaired proliferation compared to NGw/o. hAC but not OUMS-27 reduced significantly their collagen type (col) I, SOX9 and proteoglycan (PG) synthesis in HG combined with HI +/− IL-10 compared to NGw/o. IL-10 could not moderate HI and HG effects. In contrast to hAC OUMS-27 showed limited sensitivity as DM model.

Impaired Cognitive Function and Altered Hippocampal Synaptic Plasticity in Mice Lacking Dermatan Sulfotransferase Chst14/D4st1.

Chondroitin sulfate (CS) and dermatan sulfate (DS) proteoglycans (PGs) are major extracellular matrix (ECM) components of the central nervous system (CNS). A large body of evidence has shown that CSPGs/DSPGs play critical roles in neuronal growth, axon guidance, and plasticity in the developing and mature CNS. It has been proposed that these PGs exert their function through specific interaction of CS/DS chains with its binding partners in a manner that depends on the sulfation patterns of CS/DS. It has been reported that dermatan 4-O-sulfotransferase-1 (Chst14/D4st1) specific for DS, but not chondroitin 4-O-sulfotransferase-1 (Chst11/C4st1) specific for CS, regulates proliferation and neurogenesis of neural stem cells (NSCs), indicating that CS and DS play distinct roles in the self-renewal and differentiation of NSCs. However, it remains unknown whether specific sulfation profiles of DS has any effect on CNS plasticity. In the present study, Chst14/D4st1-deficient (Chst14−/−) mice was employed to investigate the involvement of DS in synaptic plasticity. First, behavior study using Morris Water Maze (MWM) showed that the spatial learning and memory of Chst14−/− mice was impaired when compared to their wild type (WT) littermates. Corroborating the behavior result, long-term potentiation (LTP) at the hippocampal CA3-CA1 connection was reduced in Chst14−/− mice compared to the WT mice. Finally, the protein levels of N-Methyl-D-aspartate (NMDA) receptor, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor, postsynaptic density 95 (PSD95), growth associated protein 43 (GAP-43), synaptophysin (SYN) and N-ethylmaleimide sensitive factor (NSF) which are important in synaptic plasticity were examined and Chst14/D4st1 deficiency was shown to significantly reduce the expression of these proteins in the hippocampus. Further studies revealed that Akt/mammalian target rapamycin (mTOR) pathway proteins, including protein kinase B (p-Akt), p-mTOR and p-S6, were significantly lower in Chst14−/− mice, which might contribute to the decreased protein expression. Together, this study reveals that specific sulfation of DS is critical in synaptic plasticity of the hippocampus and learning and memory, which might be associated with the changes in the expression of glutamate receptors and other synaptic proteins though Akt/mTOR pathway.

Keratan sulfate (KS)-proteoglycans and neuronal regulation in health and disease: the importance of KS-glycodynamics and interactive capability with neuroregulatory ligands.

Compared to the other classes of glycosaminoglycans (GAGs), that is, chondroitin/dermatan sulfate, heparin/heparan sulfate and hyaluronan, keratan sulfate (KS), have the least known of its interactive properties. In the human body, the cornea and the brain are the two most abundant tissue sources of KS. Embryonic KS is synthesized as a linear poly-N-acetyllactosamine chain of d-galactose-GlcNAc repeat disaccharides which become progressively sulfated with development, sulfation of GlcNAc is more predominant than galactose. KS contains multi-sulfated high-charge density, monosulfated and non-sulfated poly-N-acetyllactosamine regions and thus is a heterogeneous molecule in terms of chain length and charge distribution. A recent proteomics study on corneal KS demonstrated its interactivity with members of the Slit-Robbo and Ephrin-Ephrin receptor families and proteins which regulate Rho GTPase signaling and actin polymerization/depolymerization in neural development and differentiation. KS decorates a number of peripheral nervous system/CNS proteoglycan (PG) core proteins. The astrocyte KS-PG abakan defines functional margins of the brain and is up-regulated following trauma. The chondroitin sulfate/KS PG aggrecan forms perineuronal nets which aredynamic neuroprotective structures with anti-oxidant properties and roles in neural differentiation, development and synaptic plasticity. Brain phosphacan a chondroitin sulfate, KS, HNK-1 PG have roles in neural development and repair. The intracellular microtubule and synaptic vesicle KS-PGs MAP1B and SV2 have roles in metabolite transport, storage, and export of neurotransmitters and cytoskeletal assembly. MAP1B has binding sites for tubulin and actin through which it promotes cytoskeletal development in growth cones and is highly expressed during neurite extension. The interactive capability of KS with neuroregulatory ligands indicate varied roles for KS-PGs in development and regenerative neural processes.

Proteoglycans isolated from the bramble shark cartilage show potential anti-osteoarthritic properties.

Osteoarthritis (OA) causes articular cartilage destruction, initiating pain and inflammation in the joints, resulting in joint disability. Medications are available to manage these symptoms; however, their effects on the disease progression are limited. Loss of proteoglycans (PGs) was reported to contribute articular cartilage destruction in OA. Therapeutics approaches were previously studied in the animal models of OA. In the present study, we investigated the oral efficacy of four dosages of PGs (25mg/kg, 50mg/kg, 100mg/kg and 200mg/kg), isolated from the bramble shark cartilage, in an animal model of OA. Indomethacin was used as a bioequivalent formulation. Primarily, the mass spectrum analysis of the purified PGs obtained from bramble shark cartilage revealed the presence of two unique peptides including AGWLSDGSVR and LDGNPINLSK, that showed sequence similarity with aggrecan core-protein and epiphycan, respectively. The levels of C-reactive protein and uric acid in the OA rats were reduced when treated with PGs. Histopathology analysis displayed less cartilage erosion and neovascularization in OA rats treated with PGs. The X-ray imaging presented higher bone density with 200mg/kg dosage of PG treatment in OA rats. The expressions of the inflammatory modulators including TNF-α, IL-1β, MMP13, NOS2, IL-10 and COX-2 were found to be moderated with PG treatment. In addition, PG treatment maintained the activities of antioxidant enzymes, including SOD and catalase in the joint tissues with a higher GSH content, in a dose-dependent manner. Taken together, our preliminary findings report the anti-osteoarthritic properties of PGs and recommend to evaluate its efficacy and safety in randomized trials.

The Interaction(s) between Calf-Skin Hyaluronic Acid (Hyaluronan) and Dermal Type I Calf-Skin Collagen under 254 nm UV Radiation: Ability of Hyaluronan to Alter Qualitative and Quantitative Dimerization of Collagen Tyrosine Residues

The extracellular matrix (ECM) is the non-cellular component present within all tissues and organs, providing not only essential physical scaffolding for the cellular constituents and initiating crucial biochemical and biomechanical cues, required for tissue morphogenesis, differentiation and homeostasis. Roughly divided into two groups, these are 1) the main fibrous ECM proteins: collagens, elastins, fibronectins and laminins. 2) Classification of proteoglycans (PGs) is based on their location and binding. Although many different molecular interactions are possible, they depend on the cells’ condition (i.e. “Normal”, Aged, Wounded/Fibrotic, and cancerous). There is little or no data that addresses the influence of the surrounding ECM on dityrosine formation. As a simpler model, we have replaced total PG with hyaluronan (HA) and have used purified calf-skin collagen tyrosine, which forms dityrosine (A2) under 254 nm UV in buffered solution and (near) physiological temperatures. Our results reveal a complicated temperature dependence involving factors relating to collagen HA structure, and collagen’s photochemical activation parameters.

The Complex Interplay Between Extracellular Matrix and Cells in Tissues.

Extracellular matrix (ECM) maintains the structural integrity of tissues and regulates cell and tissue functions. ECM is comprised of fibrillar proteins, proteoglycans (PGs), glycosaminoglycans, and glycoproteins, creating a heterogeneous but well-orchestrated network. This network communicates with resident cells via cell-surface receptors. In particular, integrins, CD44, discoidin domain receptors, and cell-surface PGs and additionally voltage-gated ion channels can interact with ECM components, regulating signaling cascades as well as cytoskeleton configuration. The interplay of ECM with recipient cells is enriched by the extracellular vesicles, as they accommodate ECM, signaling, and cytoskeleton molecules in their cargo. Along with the numerous biological properties that ECM can modify, autophagy and angiogenesis, which are critical for tissue homeostasis, are included. Throughout development and disease onset and progression, ECM endures rearrangement to fulfill cellular requirements. The main responsible molecules for tissue remodeling are ECM-degrading enzymes including matrix metalloproteinases, plasminogen activators, cathepsins, and hyaluronidases, which can modify the ECM structure and function in a dynamic mode. A brief summary of the complex interplay between ECM macromolecules and cells in tissues and the contribution of ECM in tissue homeostasis and diseases is given.

Cloning and characterization of O-xylosyltransferase gene from Pinctada fucata martensii

ABSTRACT Glycosaminoglycan (GAG), an important component of proteoglycan (PG), was biosynthesized with the initiation by peptide O-xylosyltransferase. O-xylosyltransferase activity was presented as a marker for increased PG synthesis. In the present study, a novel O-xylosyltransferase (OXT) gene was identified from Pinctada fucata martensii (PmOXT). The PmOXT-deduced protein sequence carried a typical water-soluble carbohydrate domain, branch domain, and xylosyltransferase domain. Homologous analysis of PmOXT presented the conserved DXD motif and catalytic structure characteristics. Phylogenetic tree analysis showed the traditional taxonomy and PmOXT clustered with Crassostrea gigas. PmOXT was expressed in all the detected tissues and developmental stages. PmOXT had a significantly higher expression level in the shell formation associated tissues and developmental stages. PmOXT expressed significantly decreased in the central zone of the mantle and marginal zone of the mantle after RNA interference; additionally, OXT activity and GAG content in the extrapallial fluid were significantly reduced compared with the control. Furthermore, the crystal tablets of prismatic layer displayed obvious holes and disordered crystals with obviously rough surface and irregular crystal tablets were observed in the nacre after RNAi. Results suggested that PmOXT affected the shell formation by influencing the formation of GAGs in the process of addition to the core proteins.

Structural deciphering of the NG2/CSPG4 proteoglycan multifunctionality.

The chondroitin sulfate proteoglycan 4 ( CSPG4) gene encodes a transmembrane proteoglycan (PG) constituting the largest and most structurally complex macromolecule of the human surfaceome. Its transcript shows an extensive evolutionary conservation and, due to the elaborated intracellular processing of the translated protein, it generates an array of glycoforms with the potential to exert variant-specific functions. CSPG4-mediated molecular events are articulated through the interaction with more than 40 putative ligands and the concurrent involvement of the ectodomain and cytoplasmic tail. Alternating inside-out and outside-in signal transductions may thereby be elicited through a tight functional connection of the PG with the cytoskeleton and its regulators. The potential of CSPG4 to influence both types of signaling mechanisms is also asserted by its lateral mobility along the plasma membrane and its intersection with microdomain-restricted internalization and endocytic trafficking. Owing to the multitude of molecular interplays that CSPG4 may engage, and thanks to a differential phosphorylation of its intracellular domain accounted by crosstalking signaling pathways, the PG stands out for its unique capability to affect numerous cellular phenomena, including those purporting pathologic conditions. We discuss here the progresses made in advancing our understanding about the structural-functional bases for the ability of CSPG4 to widely impact on cell behavior, such as to highlight how its multivalency may be exploited to interfere with disease progression.-Tamburini, E., Dallatomasina, A., Quartararo, J., Cortelazzi, B., Mangieri, D., Lazzaretti, M., Perris, R. Structural deciphering of the NG2/CSPG4 proteoglycan multifunctionality.

Ezetimibe in Combination With Simvastatin Reduces Remnant Cholesterol Without Affecting Biliary Lipid Concentrations in Gallstone Patients.

BackgroundIn randomized trials (SHARP [Study of Heart and Renal Protection], IMPROVE‐IT [Improved Reduction of Outcomes: Vytorin Efficacy International Trial]), combination of statin and ezetimibe resulted in additional reduction of cardiovascular events. The reduction was greater in patients with type 2 diabetes mellitus (T2DM), where elevated remnant cholesterol and high cardiovascular disease risk is characteristic. To evaluate possible causes behind these results, 40 patients eligible for cholecystectomy, randomized to simvastatin, ezetimibe, combined treatment (simvastatin+ezetimibe), or placebo treatment during 4 weeks before surgery, were studied.Methods and ResultsFasting blood samples were taken before treatment start and at the end (just before surgery). Bile samples and liver biopsies were collected during surgery. Hepatic gene expression levels were assessed with qPCR. Lipoprotein, apolipoprotein levels, and content of cholesterol, cholesteryl ester, and triglycerides were measured after lipoprotein fractionation. Lipoprotein subclasses were analyzed by nuclear magnetic resonance. Apolipoprotein affinity for human arterial proteoglycans (PG) was measured. Biomarkers of cholesterol biosynthesis and intestinal absorption and bile lipid composition were analyzed using mass spectrometry. Combined treatment caused a statistically significant decrease in plasma remnant particles and apolipoprotein B (ApoB)/lipoprotein content of cholesterol, cholesteryl esters, and triglycerides. All treatments reduced ApoB‐lipoprotein PG binding. Simvastatin and combined treatment modified the composition of lipoproteins. Changes in biomarkers of cholesterol synthesis and absorption and bile acid synthesis were as expected. No adverse events were found.ConclusionsCombined treatment caused atheroprotective changes on ApoB‐lipoproteins, remnant particles, bile components, and in ApoB‐lipoprotein affinity for arterial PG. These effects might explain the decrease of cardiovascular events seen in the SHARP and IMPROVE‐IT trials.Clinical Trial Registration URL: www.clinicaltrialsregister.eu. Unique identifier: 2006‐004839‐30).

Polyamines stimulate the CHSY1 synthesis through the unfolding of the RNA G-quadruplex at the 5′-untraslated region

Glycosaminoglycans (GAGs), a group of structurally related acidic polysaccharides, are primarily found as glycan moieties of proteoglycans (PGs). Among these, chondroitin sulfate (CS) and dermatan sulfate, side chains of PGs, are widely distributed in animal kingdom and show structural variations, such as sulfation patterns and degree of epimerization, which are responsible for their physiological functions through interactions with growth factors, chemokines and adhesion molecules. However, structural changes in CS, particularly the ratio of 4-O-sulfation to 6-O-sulfation (4S/6S) and CS chain length that occur during the aging process, are not fully understood. We found that 4S/6S ratio and molecular weight of CS were decreased in polyamine-depleted cells. In addition, decreased levels of chondroitin synthase 1 (CHSY1) and chondroitin 4-O-sulfotransferase 2 proteins were also observed on polyamine depletion. Interestingly, the translation initiation of CHSY1 was suppressed by a highly structured sequence (positions -202 to -117 relative to the initiation codon) containing RNA G-quadruplex (G4) structures in 5'-untranslated region. The formation of the G4s was influenced by the neighboring sequences to the G4s and polyamine stimulation of CHSY1 synthesis disappeared when the formation of the G4s was inhibited by site-directed mutagenesis. These results suggest that the destabilization of G4 structures by polyamines stimulates CHSY1 synthesis and, at least in part, contribute to the maturation of CS chains.

Assessment of diagnostic value of DWI technique in the evaluation of liver fibrosis

Introduction: The liver fibrosis is caused by extracellular accumulation of cluster, glycos amino glycans and proteoglycans, which this extracellular accumulation may limit the penetration and molecular movement of water in the tissue, so the Diffusion weighted imaging(DWI) technique is due to the sensitivity to the movement and release of water molecules Can show this restriction. Using this technique, in addition to examining the entire liver, sections of the liver tissue most affected by fibrosis can also be identified. The purpose of this study was to evaluate the use of apparent diffusion coefficient (ADC) measurement in DWI imaging technique and to investigate the correlation between this method and the method of sampling in patients. Materials and Methods: Twenty-five chronic viral hepatitis C patients were examined by 1.5 Tesla MR scanner with diffusion gradient encoding in three orthogonal directions at b-values of (200, 500, 700, and 1000 s/mm2). They were correlated to biopsy finding and graded according to Ishak scoring system. Hepatic ADC values were measured for patients. Results: The best correlation between ADC values and biopsy were seen at b-values 200, 700, and 1000 s/mm2. lesser correlation was obtained at b-values of 500 s/mm2. Cut off values between different grades of fibrosis were calculated and presented in the text. Conclusion: ADC measured with DWI is a reliable non-invasive technique for quantification of liver fibrosis, and could replace liver biopsy in certain cases.

The inhibition of glycosaminoglycan incorporation influences the cell proliferation and cytodifferentiation in cultured embryonic mouse molars.

The extracellular matrix (ECM) contains a variety of complex macromolecules including proteoglycans (PGs) and glycosaminoglycans (GAGs). PG consists of a protein core with covalently attached carbohydrate side chains called GAGs. Several PGs, including versican, biglycan, decorin and syndecan are involved in odontogenesis while the role of GAGs in those PGs in this process remains unclarified. The purpose of this study was to investigate the influence of GAGs on tooth development. The mandibular first molars at early bell stage were cultivated with or without 4-methylumbelliferyl-β-D-xyloside (Xyl-MU). The cultured tooth germs were metabolically labelled with [35S] Na2SO4, then PGs in tooth germs and cultured medium were extracted separately and analyzed by gel filtration. Morphological changes were evaluated on days 2, 4, 6, and histological changes were examined by hematoxylin-eosin (HE) staining and transmission electron microscope (TEM). Related proteins and genes of cytodifferentiation were further examined by immunohistochemistry (IHC) and quantitive real-time PCR (qPCR) respectively. Meanwhile, BrdU incorporation assay was used to explore the effect of Xyl-MU on the cell proliferation of cultured tooth germs. The results demonstrated that the incorporation of GAGs to PGs in cultured tooth germs was heavily inhibited by Xyl-MU. Accompanied by the inhibition of GAGs incorporation, Xyl-MU altered tooth morphogenesis and delayed the differentiation of ameloblasts and odontoblasts. Proliferation of inner enamel epithelium (IEE) was also inhibited. Therefore, we draw a conclusion that the inhibition of GAGs incorporation influences the cell proliferation and cytodifferentiation in cultured embryonic mouse molars.

PGSE Is a Novel Enhancer Regulating the Proteoglycan Pathway of the Mammalian Golgi Stress Response.

The Golgi stress response is a homeostatic mechanism that augments the functional capacity of the Golgi apparatus when Golgi function becomes insufficient (Golgi stress). Three response pathways of the Golgi stress response have been identified in mammalian cells, the TFE3, HSP47 and CREB3 pathways, which augment the capacity of specific Golgi functions such as N-glycosylation, anti-apoptotic activity and pro-apoptotic activity, respectively. On the contrary, glycosylation of proteoglycans (PGs) is another important function of the Golgi, although the response pathway upregulating expression of glycosylation enzymes for PGs in response to Golgi stress remains unknown. Here, we found that expression of glycosylation enzymes for PGs was induced upon insufficiency of PG glycosylation capacity in the Golgi (PG-Golgi stress), and that transcriptional induction of genes encoding glycosylation enzymes for PGs was independent of the known Golgi stress response pathways and ER stress response. Promoter analyses of genes encoding these glycosylation enzymes revealed the novel enhancer elements PGSE-A and PGSE-B (the consensus sequences are CCGGGGCGGGGCG and TTTTACAATTGGTC, respectively), which regulate their transcriptional induction upon PG-Golgi stress. From these observations, the response pathway we discovered is a novel Golgi stress response pathway, which we have named the PG pathway.Key words: Golgi stress, proteoglycan, ER stress, organelle zone, organelle autoregulation.

Interrelationship of cartilage composition and chondrocyte mechanics after a partial meniscectomy in the rabbit knee joint – Experimental and numerical analysis

Site-specific and depth-dependent properties of cartilage were implemented within a finite element (FE) model to determine if compositional or structural changes in the tissue could explain site-specific alterations of chondrocyte deformations due to cartilage loading in rabbit knee joints 3 days after a partial meniscectomy (PM). Depth-dependent proteoglycan (PG) content, collagen content and collagen orientation in the cartilage extracellular matrix (ECM), and PG content in the pericellular matrix (PCM) were assessed with microscopic and spectroscopic methods. Patellar, femoral groove and samples from both the lateral and medial compartments of the femoral condyle and tibial plateau were extracted from healthy controls and from the partial meniscectomy group. For both groups and each knee joint site, axisymmetric FE models with measured properties were generated. Experimental cartilage loading was applied in the simulations and chondrocyte volumes were compared to the experimental values. ECM and PCM PG loss occurred within the superficial cartilage layer in the PM group at all locations, except in the lateral tibial plateau. Collagen content and orientation were not significantly altered due to the PM. The FE simulations predicted similar chondrocyte volume changes and group differences as obtained experimentally. Loss of PCM fixed charge density (FCD) decreased cell volume loss, as observed in the medial femur and medial tibia, whereas loss of ECM FCD increased cell volume loss, as seen in the patella, femoral groove and lateral femur. The model outcome, cell volume change, was also sensitive to applied tissue geometry, collagen fibril orientation and loading conditions.

The mechanism of naringin on the apoptosis of nucleus pulposus cells of human degenerative intervertebral disc by Wnt/β-catenin signaling pathway

Objective To study the effects of naringin on the apoptosis of nucleus pulposus cells of human degenerative intervertebral disc. Methods Nucleus pulposus cells were identified via the toluidine blue and safranin O. Next, P3 cells were cultured with naringin 0 μg/ml (control group), naringin group (10, 20, 40, 80, 100 μg/ml). After 48 hours, the best concentration of naringin was selected by cell counting kit-8 (CCK-8) and flow cytometry. β-catenin, Cyclin D1, c-Myc gene expression was detected by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR). The expression of B cell lymphoma/leukemia-2 (bcl-2), bcl-2 associated X protein (bax), Caspase-3 protein, type Ⅱ collagen and proteoglycan was determined by enzyme linked immunosorbent assay (ELISA). Western blotting detected of type Ⅱ collagen and proteoglycan expression. Results The results of cells staining were positive. CCK-8 and flow cytometry were used to determine the optimum concentration of naringin (20 μg/ml) to inhibit the apoptosis of nucleus pulposus cells. In the human degeneration nucleus pulposus cells, the expression of β-catenin gene was overexpressed and the expression of Cyclin D1 and c-Myc gene was down regulated. 20g/ml naringin could down regulate the expression of β-catenin gene (P=0.000), and up regulate the expression of Cyclin D1 and c-Myc gene (P=0.000, 0.001). The naringin (20 μg/ml) could obviously regulate up the expression of bcl-2, type Ⅱ collagen and proteoglycan protein (P=0.001, 0.000, 0.023), and regulate down the expression of bax and Caspase-3 protein, (P=0.001, 0.001). Western blotting showed that 20 μg/ml naringin could promote the expression of type Ⅱ collagen and proteoglycan. Conclusion Naringin may inhibit the apoptosis of nucleus pulposus cells by regulating the Wnt/β-catenin pathway and the mitochondrial apoptosis pathway. Key words: Naringin; Human nucleus pulpous; Apoptosis; Intervertebral disc; Degeneration

Dilated Minute Chambers in Laryngeal Vocal Fold Polyps: Histopathological and Ultrastructural Features

In Reinke's space of human vocal fold, type III collagen forms a three dimensional network and this contains numerous minute chambers in between these fibers. These compartments are occupied by glycosaminoglycans and glycoproteins. In laryngeal fold lesions, such as Reinke's edema and vocal fold polyps, proteoglycan (PG)/hyaluronic acid (HA) components of extracellular matrix increased. We investigated the size and quantity of the minute chambers within Reinke's space, filled with PG/HA with the aid of transmission electron microscopy. Eight vocal fold polyps and 10 mucosal biopsies (as control group) were all evaluated by light microscopy and electron microscopy. We detected that PG/HA in extracellular matrix had been increased in vocal fold lesions when compared with control group, by Alcian Blue-pH 2.5 stain. The mean volume of the chambers in Reinke's space of normal larynx was measured as 0.040233 µm2 whereas the mean volume of these chambers in vocal fold polyps was measured as 6.420221 µm2. The difference between the volumes of these chambers in vocal fold polyps and in control group was statistically significant (P = 0.001). Within these chambers PG/HA were found and PG/HA filling these chambers were increased in vocal fold polyps. We think proteoglycan and glycosaminoglycans, especially HA, play an important role in determining biochemical properties of vocal fold lesions.

A novel mechanobiological model can predict how physiologically relevant dynamic loading causes proteoglycan loss in mechanically injured articular cartilage

Cartilage provides low-friction properties and plays an essential role in diarthrodial joints. A hydrated ground substance composed mainly of proteoglycans (PGs) and a fibrillar collagen network are the main constituents of cartilage. Unfortunately, traumatic joint loading can destroy this complex structure and produce lesions in tissue, leading later to changes in tissue composition and, ultimately, to post-traumatic osteoarthritis (PTOA). Consequently, the fixed charge density (FCD) of PGs may decrease near the lesion. However, the underlying mechanisms leading to these tissue changes are unknown. Here, knee cartilage disks from bovine calves were injuriously compressed, followed by a physiologically relevant dynamic compression for twelve days. FCD content at different follow-up time points was assessed using digital densitometry. A novel cartilage degeneration model was developed by implementing deviatoric and maximum shear strain, as well as fluid velocity controlled algorithms to simulate the FCD loss as a function of time. Predicted loss of FCD was quite uniform around the cartilage lesions when the degeneration algorithm was driven by the fluid velocity, while the deviatoric and shear strain driven mechanisms exhibited slightly discontinuous FCD loss around cracks. Our degeneration algorithm predictions fitted well with the FCD content measured from the experiments. The developed model could subsequently be applied for prediction of FCD depletion around different cartilage lesions and for suggesting optimal rehabilitation protocols.

Conventional Anti-glioblastoma Chemotherapy Affects Proteoglycan Composition of Brain Extracellular Matrix in Rat Experimental Model in vivo.

Temozolomide (TMZ) is a conventional chemotherapy drug for adjuvant treatment of glioblastoma multiforme (GBM), often accompanied by dexamethasone (DXM) to prevent brain oedema and alleviate clinical side effects. Here, we aimed to investigate an ability of the drugs to affect normal brain tissue in terms of proteoglycan (PG) composition/content in experimental rat model in vivo. Age- and brain zone-specific transcriptional patterns of PGs were demonstrated for 8, 60, and 120 days old rats, and syndecan-1, glypican-1, decorin, biglycan, and lumican were identified as the most expressed PGs. DXM treatment affected both PG core proteins expression (mainly syndecan-1, glypican-1, decorin, biglycan, lumican, versican, brevican, and NG2) and heparan sulphate (HS)/chondroitin sulphate (CS) content in organotypic brain slice culture ex vivo and experimental animals in vivo in a dose-dependent manner. TMZ treatment did not result in the significant changes in PG core proteins expression both in normal rat brain hippocampus and cortex in vivo (although generics did), but demonstrated significant effects onto polysaccharide HS/CS content in the brain tissue. The effects were age- and brain zone-specific and similar with the age-related PGs expression changes in rat brain. Combination of TMZ with DXM resulted in the most profound deterioration in PGs composition and content in the brain tissue both at core protein and glycosaminoglycan levels. Taken together, the obtained results demonstrate that conventional anti-glioblastoma therapy affects proteoglycan structure and composition in normal brain tissue, potentially resulting in deterioration of brain extracellular matrix and formation of the favourable tumorigenic niche for the expansion of the residual glioma cells. During the TMZ chemotherapy, dose and regimen of DXM treatment matter, and repetitive low DXM doses seem to be more sparing treatment compared with high DXM dose(s), which should be avoided where possible, especially in combination with TMZ.

Deferoxamine-Soaked Suture Improves Angiogenesis and Repair Potential After Acute Injury of the Chicken Achilles Tendon.

Background:A major obstacle to the treatment of soft tissue injuries is the hypovascular nature of the tissues. Deferoxamine (DFO) has been shown to stimulate angiogenesis by limiting the degradation of intracellular hypoxia-inducible factor 1–alpha.Hypothesis:DFO-saturated suture would induce angiogenesis and improve the markers of early healing in an Achilles tendon repair model.Study Design:Controlled laboratory study.Methods:Broiler hens were randomly assigned to the control (CTL) group or DFO group (n = 9 per group). The right Achilles tendon was partially transected at its middle third. The defect was surgically repaired using 3-0 Vicryl suture soaked in either sterile water (CTL group) or 324 mM DFO solution (DFO group). All animals were euthanized 2 weeks after the injury, and the tendon was harvested. Half of the tendon was used to evaluate angiogenesis via hemoglobin content and tissue repair via DNA content and proteoglycan (PG) content. The other half of the tendon was sectioned and stained with hematoxylin and eosin, safranin O, and lectin to evaluate vessel density.Results:Hemoglobin content (percentage of wet tissue weight) was significantly increased in the DFO group compared with the CTL group (0.081 ± 0.012 vs 0.063 ± 0.016, respectively; P = .046). DNA content (percentage of wet tissue weight) was also significantly increased in the DFO group compared with the CTL group (0.31 ± 0.05 vs 0.23 ± 0.03, respectively; P = .024). PG content (percentage of wet tissue weight) was significantly decreased in the DFO group compared with the CTL group (0.26 ± 0.02 vs 0.33 ± 0.08, respectively; P = .035). Total chondroid area (number of vessels per mm2 of tissue area evaluated) was significantly decreased in the DFO group compared with the CTL group (17.2 ± 6.6 vs 24.6 ± 5.1, respectively; P = .038). Articular zone vessel density (vessels/mm2) was significantly increased in the DFO group compared with the CTL group (7.1 ± 2.5 vs 2.1 ± 0.9, respectively; P = .026).Conclusion:The significant increase in hemoglobin content as well as articular zone vessel density in the DFO group compared with the CTL group is evidence of increased angiogenesis in the fibrocartilaginous region of the tendon exposed to DFO. The DFO group also displayed a significantly greater level of DNA and significantly lower level of PG, suggesting enhanced early healing by fibrous tissue formation.Clinical Relevance:Stimulating angiogenesis by DFO-saturated suture may be clinically useful to improve healing of poorly vascularized tissues.

Fibromodulin: Structure, Physiological Functions, and an Emphasis on its Potential Clinical Applications in Various Diseases.

Fibromodulin (FMOD) is one of the small leucine-rich proteoglycans. A search of the literature did not reveal any paper that specifically reviews the potential clinical applications of FMOD in the management of human diseases. First, the structure and physiological functions of FMOD were reviewed. Then its potential clinical applications in various diseases including diseases of the skin, tendons, joints, intervertebral discs, blood vessels, teeth, uterus, bone and kidney were reviewed. FMOD is able to switch the adult response to skin wounding to the desired fetal response of scarless healing. Lowered levels of FMOD would be desirable in the management of tendinopathy, uterine fibroids, tumors resistant to radiotherapy, glioblastomas, small-cell lung cancer, and primary liver/lung fibrosis. In contrast, increased levels of FMOD would be desirable in the management of acute tendon injuries, osteoarthritis, rheumatoid arthritis, temporo-mandibular disease, joint laxity, intervertebral disc disease, neo-intimal hyperplasia of vein grafts, teeth caries, periodontal disease, endometrial atrophy, osteoporosis and diabetic nephropathy. Furthermore, FMOD may be used as a prognostic marker of cerebrovascular events in patients undergoing carotid endarterectomy and a marker for prostatic cancer. Finally, the use of FMOD in the treatment of symptomatic endometrial atrophy should be explored in women who are unable to use the standard estrogen management for endometrial atrophy. The review concluded that clinical trials in humans should be initiated to investigate the potential therapeutic effects of FMOD.