Hyaluronan synthesis

Chitoohgomers act as templates for hyaluronan synthesis. Hyaluronan has been shown to promote cell motility, adhesion and prohferation, and... 

Lishanti, U. et al., Inhibition of hyaluronan degradation by dextran sulphate facilitates characterization of hyaluronan synthesis an in vitro and in vivo study, Glycoconjugate J., 20, 461, 2004. 

After my return to Boston, I extended my work on hyaluronan from the vitreus and the rooster comb to the synovial fluid. The physical properties, such as viscosity and elasticity, of synovial fluid were poorly understood, especially in human joints. I started to investigate the physical properties of cattle synovial fluid. As I had done 20 years earlier in Budapest, I went to the slaughterhouses of the Boston area and collected joint fluids. This time I was interested in how aging affects the physical properties and hyaluronan content of the joint fluid. The physical properties or, in more scientific terms, the rheology of the fluid is important because its role is to protect and lubricate the tissues of the joint. I traveled to Iowa to collect synovial fluids from cattle herds fed various diets that contained hormones. I hoped to discover a hormonal control of hyaluronan synthesis, similar to the one Szirmai and I had found that controlled hyaluronan synthesis in the rooster comb. 

Fig. 6.11 Linker glycan for chondroitin sulfate synthesis. In the Golgi, the serine residue -OH group on a protein activates a specific synthetase in the Golgi membrane to transfer UDP-xylose. UDP is lost in making the attachment shown. UDP-activated galactose and glucuronate are then added by other synthetases before chondroitin sulfate synthetase is activated each donor loses its UDP unlike hyaluronan synthesis. Keratan sulfate is added different linker glycans (Adapted from Fig. 19-39 in The Molecular Biology of the Cell. B. Alberts et al., 4th Ed. 2002. Garland Science, Taylor Francis Group, New York)...

The aqueous humor is characterized by a high ascorbic acid concentration, and addition of ascorbic acid to the medium of human trabecular meshwork cells in culture resulted in a significant dose-dependent stimulation of hyaluronan synthesis and secretion (26). 

Smith TJ, Parikh SJ. HMC-1 mast cells activate human orbital fibroblasts in coculture evidence for up-regulation of prostaglandin E2 and hyaluronan synthesis. Endocrinology 1999 140 3518-3525. 

Ellis IR, Schor SL. Differential effects of TGF-p 1 on hyaluronan synthesis by fetal and adult skin fibroblasts implications for cell migrationa and wound healing. Exp Cell Res 1996 228 326-333. 

Crescenzi V, Francescangeli A, Renier D, Bellini D. New cross-linked and sulfated derivatives of partially deacetylated hyaluronan synthesis and preliminary characterization. Biopolymers 2002 64 86-94. 

BHA 09] Bharadwaj A.G., KOVAR J.L., Loughman E. et al, Spontaneous Metastasis of Prostate Cancer Is Promoted by Excess Hyaluronan Synthesis and Pmcess,m American Jaumal of Pathology, vo. 174, pp. 1027-1036, 2009. 

Graves, M.V., Burbanc, D.E., Roth, R., Heuser, J., DeAngelis, P.L., van Etten, J.L. (1999) Hyaluronan synthesis in virus PBCV-1-infected chlorella- like green algae. Virology, 257, 15-23. 

Karvinen, S., Pasonen-Seppanen, S., Hyltinen, J. (2003) Keratinocyte growth factor stimulates migration and hyaluronan synthesis in the epidermis by activation of keratinocyte hyaluronan synthases 2 and 3. Journal of Biological Chemistry, 278, (49), 49495—49504. 

Heldin, P. Laurent, T.C. Heldin, C-H. Effect of growth factors on hyaluronan synthesis in cultured human fibroblasts. Biochem. J. 1989,258, 919-922. 

Tirone, E. D Alessandris, C. Hascall, V. C. Siracusa, G. Salustri, A. Hyaluronan synthesis by mouse cumulus cells is regulated by interactions between follicle-stimulating hormone (or epidermal growth factor) and a soluble oocyte factor (or transforming growth factor-pi). J. Biol. Chem. 1997,272, 4787-4794. 

Yung, S. Coles, G. A. Davies, M. IL-ip, a major stimulator of hyaluronan synthesis in vitro of human peritoneal mesothelial cells Relevance to peritonitis in CAPD. Kidney Intern. 1996, 50, 1337-1343. 

Smith, T. J. Wang, H.-S. Evans, C. H. Leukoregulin is a potent inducer of hyaluronan synthesis in cultured human orbital fibroblasts. Am. J. Physiol 1995, 268, C382-C388. 

Another interesting system in which hyaluronan plays an important role is expansion of the cumulus oophorus during ovulation. In response to follicle stimulating hormone and a factor produced by the oocyte, hyaluronan synthesis by the cumulus cells surrounding the oocyte increases dramatically [32], A stable, gel-like matrix is formed between the cumulus cells due to crosslinking of hyaluronan by inter-a-trypsin inhibitor and TSG-6 [31, 32]. This matrix is responsible for the integrity of the cumulus cell-oocyte complex which is required for protection and transport of the oocyte during ovulation, entry into the oviduct and fertilization. Sperm-associated hyaluronidases allow penetration of this matrix at fertilization. 

Ellis I, Banyard J, Schor SL. Differential response of fetal and adult fibroblasts to cytokines cell migration and hyaluronan synthesis. Development 1997 124 1593-1600. 

Enhanced availability of exogenous glucosamine is beneficial for the synthesis of hyaluronan because endogenous glucosamine is insufficient to achieve the high concentration of UDP-N-acetyl glucosamine necessary to... 

Dehydrativeglycosylation of 1-hydroxy donors with Ph2S0/Tf20 in conjunction with thioglycoside acceptors opens the way for sequential double glycosylation, one-pot procedures for trisaccharide synthesis, as exemplified by the efficient one-pot synthesis of the a-Gal epitope and a hyaluronan trisaccharide [566]. This study also shows the potential of selenoglycoside as acceptors in dehydrative glycosylation (Scheme 4.112). 

Such enzymatic catalyzed polycondensations have allowed the synthesis of a number of natural polysaccharides, but has also allowed the production of nonnatural polysaccharides such as cellulose-xylan hybrids and functionalized hyaluronan, chondroitin sulfate, and chondroitin. Such work illustrates the ever-narrowing bridge between natural and synthetic polymers and polymer syntheses. 

One such application could be delivery of Has2-pDNA, a plasmid that codes for hyaluronan synthase 2 [66]. This enzyme facilitates the synthesis of larger HA molecules and can prevent post-surgical peritoneal adhesions. In one study, DNA-HA films were prepared using previously-described chemistry however, lyophili-zation was replaced with air-drying under sterile conditions and an isopropanol/ H20 mixture was used instead of DMF/H20. The release kinetics of DNA were similar to that from the HA film described previously, but release did not occur until after 7 days. The reason for this delay was not completely clear the authors suggest that a possible way to overcome the delay is to use a crosslinked DNA-HA film sandwiched between two non-crosslinked DNA-HA films. Non-crosslinked film... 

As an extension of the HA film approach, Yun and coworkers [32] synthesized hyaluronan microspheres using the chemistry described above, but the synthesis was completed in emulsion in one step, yielding 5- to 20-pm microspheres. These microspheres were found to be biodegradable and released three times more pDNA when incubated with hyaluronidase in PBS (phosphate buffered saline) solution (vs enzyme-free PBS). As in the case of films, DNA release from the microspheres was dependent on the DNA loading. DNA-HA microspheres were not directly used for transfection instead, DNA obtained from release experiments was used in transfection of Chinese hamster ovary (CHO) cells using Lipofectamine. The relative levels of transfection over time had the same trend as DNA release from the DNA-HA microspheres and confirmed that released DNA is bioactive. 

Hyaluronan hinders the onset of differentiation, as discussed earlier. Retinoic acid retards the differentiation of epidermal keratinocytes, as shown in skin organ cultures, a result of the ability of retinoic acid to stimulate HA deposition.263-265 Retinoic acid leads to the accumulation of HA in the superficial layers of the epidermis by stimulating HA synthesis specifically in keratinocytes. Some of this accumulation occurs as expanded intercellular HA, which may account for the weakened cohesion of keratinocytes observed both in vivo and in vitro. 

Heparin/heparan, hyaluronan, and chondroitin are three prevalent glycosaminoglycans. Vertebrates use glycosaminoglycans in structural, recognition, adhesion, and signaling roles. Chemical synthesis of naturally occurring polysaccharides is considered to be impractical. Most polysaccharides, especially those from bacteria origins, are obtained by purification from natural sources or from cell culture, enzymatic approaches have been increasingly applied to obtain some structures. 

Hyaluronan (hyaluronic acid, HA) is a highly anionic unbranched linear polymer containing a -GlcAfSl,4GlcNAcP 1,4-repeating unit, which plays important roles in modulating cell adhesion, signaling, and motility. Several enzymes responsible for HA synthesis, namely Hyaluronic Acid Synthases, have been cloned from bacteria and mammals (107, 108). 

DeAngelis PL, Oatman LC, Gay DF. Rapid chemoenzymatic synthesis of monodisperse hyaluronan oligosaccharides with immobilized enzyme reactors. J. Biol. Chem. 2003 278 35199-35203. 

During these years, our work laid the foundation for future studies on the effect of elastoviscous solutions of hyaluronan on the migration, proliferation and function of white blood cells, and how such solutions affect some functions of the immune system. We discovered that hyaluronan regulates the synthesis of glycosaminoglycans in in vitro systems, and regulates inflammation and tissue regeneration in adult animal models and tissues. All these studies laid the theoretical foundation for the therapeutic applications of hyaluronan. 

---