Evidence that the serum inhibitor of hyaluronidase may be a member of the inter-alpha-inhibitor family

Defining the versican interactome in lung health and disease

The extracellular matrix (ECM) imparts critical mechanical and biochemical information to cells in the lungs. Proteoglycans are essential constituents of the ECM and play a crucial role in controlling numerous biological processes, including regulating cellular phenotype and function. Versican, a chondroitin sulfate proteoglycan required for embryonic development, is almost absent from mature, healthy lungs and is reexpressed and accumulates in acute and chronic lung disease. Studies using genetically engineered mice show that the versican-enriched matrix can be pro- or anti-inflammatory depending on the cellular source or disease process studied. The mechanisms whereby versican develops a contextual ECM remain largely unknown. The primary goal of this review is to provide an overview of the interaction of versican with its many binding partners, the "versican interactome," and how through these interactions, versican is an integrator of complex extracellular information. Hopefully, the information provided in this review will be used to develop future studies to determine how versican and its binding partners can develop contextual ECMs that control select biological processes. Although this review focuses on versican and the lungs, what is described can be extended to other proteoglycans, tissues, and organs.

Plasma hyaluronan, hyaluronidase activity and endogenous hyaluronidase inhibition in sepsis: an experimental and clinical cohort study

Background

Plasma hyaluronan concentrations are increased during sepsis but underlying mechanisms leading to high plasma hyaluronan concentration are poorly understood. In this study we evaluate the roles of plasma hyaluronan, effective plasma hyaluronidase (HYAL) activity and its endogenous plasma inhibition in clinical and experimental sepsis. We specifically hypothesized that plasma HYAL acts as endothelial glycocalyx shedding enzyme, sheddase.

Methods

Plasma hyaluronan, effective HYAL activity and HYAL inhibition were measured in healthy volunteers (n = 20), in patients with septic shock (n = 17, day 1 and day 4), in patients with acute pancreatitis (n = 7, day 1 and day 4) and in anesthetized and mechanically ventilated pigs (n = 16). Sixteen pigs were allocated (unblinded, open label) into three groups: Sepsis-1 with infusion of live Escherichia coli (E. coli) 1 × 10⁸ CFU/h of 12 h (n = 5), Sepsis-2 with infusion of E. coli 1 × 10⁸ CFU/h of 6 h followed by 1 × 10⁹ CFU/h of the remaining 6 h (n = 5) or Control with no E. coli infusion (n = 6).

Results

In experimental E. coli porcine sepsis and in time controls, plasma hyaluronan increases with concomitant decrease in effective plasma HYAL activity and increase of endogenous HYAL inhibition. Plasma hyaluronan increased in patients with septic shock but not in acute pancreatitis. Effective plasma HYAL was lower in septic shock and acute pancreatitis as compared to healthy volunteers, while plasma HYAL inhibition was only increased in septic shock.

Conclusion

Elevated plasma hyaluronan levels coincided with a concomitant decrease in effective plasma HYAL activity and increase of endogenous plasma HYAL inhibition both in experimental and clinical sepsis. In acute pancreatitis, effective plasma HYAL activity was decreased which was not associated with increased plasma hyaluronan concentrations or endogenous HYAL inhibition. The results suggest that plasma HYAL does not act as sheddase in sepsis or pancreatitis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40635-021-00418-3.

Synthesis and biological evaluations of oleanolic acid indole derivatives as hyaluronidase inhibitors with enhanced skin permeability

Oleanolic acid (OA) is a natural cosmeceutical compound with various skin beneficial activities including inhibitory effect on hyaluronidase but the anti-hyaluronidase activity and mechanisms of action of its synthetic analogues remain unclear. Herein, a series of OA derivatives were synthesised and evaluated for their inhibitory effects on hyaluronidase. Compared to OA, an induction of fluorinated (6c) and chlorinated (6g) indole moieties led to enhanced anti-hyaluronidase activity (IC₅₀ = 80.3 vs. 9.97 and 9.57 µg/mL, respectively). Furthermore, spectroscopic and computational studies revealed that 6c and 6g can bind to hyaluronidase protein and alter its secondary structure leading to reduced enzyme activity. In addition, OA indole derivatives showed feasible skin permeability in a slightly acidic environment (pH = 6.5) and 6c exerted skin protective effect by reducing cellular reactive oxygen species in human skin keratinocytes. Findings from the current study support that OA indole derivatives are potential cosmeceuticals with anti-hyaluronidase activity.

Hyaluronidase: An overview of its properties, applications, and side effects

Hyaluronidase, an enzyme that breaks down hyaluronic acid, has long been used to increase the absorption of drugs into tissue and to reduce tissue damage in cases of extravasation of a drug. With the increasing popularity of hyaluronic acid filler, hyaluronidase has become an essential drug for the correction of complications and unsatisfactory results after filler injection. For this reason, when performing procedures using hyaluronic acid filler, a sufficient knowledge of hyaluronidase is required. In order for hyaluronidase to dissolve a hyaluronic acid filler, it must interact with its binding sites within the hyaluronic acid. The reaction of a filler to hyaluronidase depends on the hyaluronic acid concentration, the number of crosslinks, and the form of the filler. Hyaluronidase is rapidly degraded and deactivated in the body. Therefore, in order to dissolve a hyaluronic acid filler, a sufficient amount of hyaluronidase must be injected close to the filler. If the filler is placed subcutaneously, injection of hyaluronidase into the filler itself may help, but if the filler is placed within a blood vessel, it is sufficient to inject hyaluronidase in the vicinity of the vessel, instead of into the filler itself. Allergic reactions are a common side effect of hyaluronidase. Most allergic reactions to hyaluronidase are local, but systemic reactions may occur in infrequent cases. Since most allergic responses to hyaluronidase are immediate hypersensitivity reactions, skin tests are recommended before use. However, some patients experience delayed allergic reactions, which skin tests may not predict.

The Inter-α-Trypsin Inhibitor Family: Versatile Molecules in Biology and Pathology

Inter-α-trypsin inhibitor (IαI) family members are ancient and unique molecules that have evolved over several hundred million years of vertebrate evolution. IαI is a complex containing the proteoglycan bikunin to which heavy chain proteins are covalently attached to the chondroitin sulfate chain. Besides its matrix protective activity through protease inhibitory action, IαI family members interact with extracellular matrix molecules and most notably hyaluronan, inhibit complement, and provide cell regulatory functions. Recent evidence for the diverse roles of the IαI family in both biology and pathology is reviewed and gives insight into their pivotal roles in tissue homeostasis. In addition, the clinical uses of these molecules are explored, such as in the treatment of inflammatory conditions including sepsis and Kawasaki disease, which has recently been associated with severe acute respiratory syndrome coronavirus 2 infection in children.

Endothelial glycocalyx restoration by growth factors in diabetic nephropathy

The endothelial glycocalyx (eGlx) constitutes the first barrier to protein in all blood vessels. This is particularly noteworthy in the renal glomerulus, an ultrafiltration barrier. Leakage of protein, such as albumin, across glomerular capillaries results in albumin in the urine (albuminuria). This is a hall mark of kidney disease and can reflect loss of blood vessel integrity in microvascular beds elsewhere. We discuss evidence demonstrating that targeted damage to the glomerular eGlx results in increased glomerular albumin permeability. EGlx is lost in diabetes and experimental models demonstrate loss from glomerular endothelial cells. Vascular endothelial growth factor (VEGF)A is upregulated in early diabetes, which is associated with albuminuria. Treatment with paracrine growth factors such as VEGFC, VEGF165b and angiopoietin-1 can modify VEGFA signalling, rescue albumin permeability and restore glomerular eGlx in models of diabetes. Manipulation of VEGF receptor 2 signalling, or a common eGlx biosynthesis pathway by these growth factors, may protect and restore the eGlx layer. This would help to direct future therapeutics in diabetic nephropathy.

Comparative Effectiveness of Different Interventions of Perivascular Hyaluronidase

BACKGROUND

Soft-tissue necrosis caused by vascular compromise is a frequent and troublesome complication of hyaluronic acid filler injection. Hyaluronidase has been proposed as a treatment for this condition. This study aimed to determine the effective dose and administration interval of hyaluronidase injection in a skin necrosis animal model.

METHODS

New Zealand rabbits were used to simulate the hyaluronic acid-associated vascular occlusion model. Hyaluronic acid filler (0.1 ml) was injected into the central auricular artery to create an occlusion. Three rabbit auricular flaps were injected with 500 IU of hyaluronidase once (group A) and three flaps each were injected at 15-minute intervals with 250 IU of hyaluronidase twice (group B), 125 IU of hyaluronidase four times (group C), 100 IU of hyaluronidase five times (group D), and 75 IU of hyaluronidase seven times (group E), all at 24 hours after occlusion. No intervention was administered after occlusion in the control group. Flap fluorescence angiography was performed immediately after hyaluronidase injection and on postoperative days 2, 4, and 7. Flap necrotic areas were analyzed.

RESULTS

All control and experimental flaps demonstrated total occlusion after hyaluronic acid injection. The average total survival rate (positive area/total area ×100 percent) of control flaps was 37.61 percent. For experimental groups, the average total survival rates were 74.83 percent, 81.49 percent, 88.26 percent, 56.48 percent, and 60.69 percent in groups A through E, respectively.

CONCLUSION

A better prognosis can be obtained by administering repeated doses rather than a single high dose of hyaluronidase.

Dermatan sulfate oligosaccharides having reducing end 2, 5-anhydro-d-talose inhibit bovine testicular hyaluronidase activity

Dermatan sulfate oligosaccharides having reducing end 2,5-anhydro-d-talose were prepared by partial N-deacetylation of dermatan sulfate polysaccharide with hydrazine followed by deamination with nitrous acid, and the effect of these oligosaccharides on the activity of bovine testicular hyaluronidase was investigated. Hydrolysis activity and transglycosylation activity of this enzyme were assessed in an independent reaction system by analyzing the products by HPLC. Dermatan sulfate oligosaccharides inhibited hyaluronan hydrolysis by bovine testicular hyaluronidase. Kinetic analysis of the hydrolysis reaction revealed that the inhibition mode by dermatan sulfate oligosaccharides was as competitive as that previously shown by chondroitin sulfate oligosaccharides. Transglycosylation of hyaluronan by bovine testicular hyaluronidase, as a reverse reaction of hydrolysis of hyaluronan, was also inhibited. These inhibitory effects were dependent on the dose and sulfation degree of dermatan sulfate.

Identification and characterization of a bacterial hyaluronidase and its production in recombinant form

Hyaluronidases (Hyals) are broadly used in medical applications to facilitate the dispersion and/or absorption of fluids or medications. This study reports the isolation, cloning, and industrial-scale recombinant production, purification and full characterization, including X-ray structure determination at 1.45 Å, of an extracellular Hyal from the nonpathogenic bacterium Streptomyces koganeiensis. The recombinant S. koganeiensis Hyal (rHyal_Sk) has a novel bacterial catalytic domain with high enzymatic activity, compared with commercially available Hyals, and is more thermostable and presents higher proteolytic resistance, with activity over a broad pH range. Moreover, rHyal_Sk exhibits remarkable substrate specificity for hyaluronic acid (HA) and poses no risk of animal cross-infection.

Sugars in the microenvironment: the sticky problem of HA turnover in tumors

The properties and behavior of tumor cells are closely regulated by their microenvironment. Accordingly, stromal cells and extracellular matrix components can have a pronounced effect on cancer initiation, growth, and progression. The linear glycosaminoglycan hyaluronan (HA) is a major component of the extracellular matrix. Altered synthesis and degradation of HA in the tumor context has been implicated in many aspects of tumor biology. In particular, the accumulation of small HA oligosaccharides (sHA) in the tumor interstitial space may play a decisive role, due to the ability of sHA to activate a number of biological processes that are not modulated by high molecular weight (HMW)-HA. In this article, we review the normal physiological role and metabolism of HA and then survey the evidence implicating HA in tumor growth and progression, focusing in particular on the potential contribution of sHA to these processes.

Hyaluronan in wound healing: rediscovering a major player

Wound healing involves a series of carefully modulated steps, from initial injury and blood clot to the final reconstituted tissue or scar. A dynamic reciprocity exists throughout between the wound, blood elements, extracellular matrix, and cells that participate in healing. Multiple cytokines and signal transduction pathways regulate these reactions. A major component throughout most of the process is hyaluronan, a straight-chain carbohydrate extracellular matrix polymer. Hyaluronan occurs in multiple forms, chain length being the only distinguishing characteristic between them. Levels of hyaluronan in its high-molecular-weight form are prominent in the earliest stages of wound repair. Progressively more fragmented forms occur in a manner not previously appreciated. We outline here steps in the wound healing cascade in which hyaluronan participates, as well as providing a review of its metabolism. Although described by necessity in a series of quantum steps, the healing process is constituted by a smooth continuum of overlapping reactions. The prevalence of hyaluronan in the wound (initially termed "hexosamine-containing mucopolysaccharide"), particularly in its early stages, was pointed out over half a century ago by the Harvard surgeon J. Engelbert Dunphy. It appears we are now returning to where we started.

Clinical Immunogenicity of rHuPH20, a Hyaluronidase Enabling Subcutaneous Drug Administration

Recombinant human PH20 hyaluronidase (rHuPH20) is used to facilitate dispersion of subcutaneously delivered fluids and drugs. This report summarizes rHuPH20 immunogenicity findings from clinical trials where rHuPH20 was co-administered with SC human immunoglobulin, trastuzumab, rituximab, or insulin. Plasma samples were obtained from evaluable subjects participating in ten different clinical trials as well as from healthy plasma donors. A bridging immunoassay and a modified hyaluronidase activity assay were used to determine rHuPH20-reactive antibody titers and neutralizing antibodies, respectively. rHuPH20-binding antibody populations from selected subjects with positive titers were affinity-purified and subjected to further characterization such as cross-reactivity with endogenous PH20. Among individual trials, the prevalence of pre-existing rHuPH20-reactive antibodies varied between 3 and 12%, excepting the primary immunodeficiency (PID) studies. Incidence of treatment-induced rHuPH20 antibodies was 2 to 18%, with the highest titers (81,920) observed in PID. No neutralizing antibodies were observed. Within most trials, the kinetics of antibody responses were comparable between pre-existing and treatment-induced antibody responses, although responses classified as persistent were more common in subjects with pre-existing titers. There was no association between antibody positivity and either local or systemic adverse events. Pre-existing and treatment-induced antibody populations were of similar immunoglobulin isotypes and cross-reacted to endogenous PH20 to similar extents. No cross-reactivity to PH20 paralogs was detected. rHuPH20 induces only modest immunogenicity which has no association with adverse events. In addition, antibodies purified from baseline-positive individuals are qualitatively similar to those purified from individuals developing rHuPH20-reactive antibodies following exposure to the enzyme.

Solubilized extracellular matrix from brain and urinary bladder elicits distinct functional and phenotypic responses in macrophages

Extracellular matrix (ECM) derived from a variety of source tissues has been successfully used to facilitate tissue reconstruction. The recent development of solubilized forms of ECM advances the therapeutic potential of these biomaterials. Isolated, soluble components of ECM and matricryptic peptides have been shown to bias macrophages toward a regulatory and constructive (M2-like) phenotype. However, the majority of studies described thus far have utilized anatomically and morphologically similar gastrointestinal derived ECMs (small intestine, esophagus, urinary bladder, etc.) and a small subset of macrophage markers (CD206, CD86, CCR7) to describe them. The present study evaluated the effect of solubilized ECM derived from molecularly diverse source tissues (brain and urinary bladder) upon primary macrophage phenotype and function. Results showed that solubilized urinary bladder ECM (U-ECM) up-regulated macrophage PGE2 secretion and suppressed traditional pro-inflammatory factor secretion, consistent with an M2-like phenotype. The hyaluronic acid (HA) component in solubilized U-ECM played an important role in mediating this response. Brain ECM (B-ECM) elicited a pro-inflammatory (M1-like) macrophage response and contained almost no HA. These findings suggest that the molecular composition of the source tissue ECM plays an important role in influencing macrophage function and phenotype.

Inhibitory effect of chondroitin sulfate oligosaccharides on bovine testicular hyaluronidase

Hyaluronan and chondroitin sulfates are prominent components of the extracellular matrices of animal tissues; however, their functions in relation to their oligosaccharide structures have not yet been fully elucidated. The oligosaccharides of hyaluronan and chondroitin sulfate were prepared and used to investigate their effects on the hydrolysis and transglycosylation reactions of bovine testicular hyaluronidase when hyaluronan was used as a substrate. Hydrolysis and transglycosylation activities were assessed in independent reaction systems by analyzing the products by HPLC. The hydrolysis and transglycosylation reactions of bovine testicular hyaluronidase were dose-dependently inhibited by chondroitin sulfate oligosaccharides, but not by hyaluronan or chondroitin oligosaccharides. A kinetic analysis of the hydrolysis reaction using hyaluronan octasaccharide revealed that the inhibition mode by chondroitin sulfate oligosaccharides was competitive.

Hyaluronidase-1 expression promotes lung metastasis in syngeneic mouse tumor models without affecting accumulation of small hyaluronan oligosaccharides in tumor interstitial fluid

Enhanced levels in tumors of hyaluronan, a glycosaminoglycan component of the extracellular matrix, and hyaluronidases such as hyaluronidase-1 (Hyal1) that degrade hyaluronan have both been linked to poor prognosis and metastasis, suggesting that the turnover of hyaluronan might contribute to tumor progression. Small hyaluronan oligosaccharides (sHA) can accumulate in tumor interstitial fluid (TIF), and have been implicated in a number of processes that drive tumor progression, including MMP expression and angiogenesis. The properties of Hyal1 suggest that it might contribute to the degradation of hyaluronan in tumors and the subsequent accumulation of sHA. Accumulation of Hyal1-produced sHA may therefore account for the association between Hyal1 and metastasis. Here we have investigated this hypothesis using mouse syngeneic breast tumor models. Specifically, we modulated Hyal1 expression and activity either in the tumor cells themselves, or in the stromal compartment by using Hyal1 knockout (KO) mice. These approaches did not change sHA levels in TIF, but nevertheless fostered metastasis to the lung in some of the models used in the study. Together, these data suggest that Hyal1 can promote lung metastasis in a manner that is not dependent on altered accumulation of sHA in TIF.

Tailored doxorubicin-hyaluronan conjugate as a potent anticancer glyco-drug: an alternative to prodrug approach

Releasibility of doxorubicin from drug-conjugates is believed to be a prerequisite for its anti-cancer activity. Here, a new glyco-drug approach that circumvents the releasibility restriction is reported, opening a new possibility to design efficient, target specific drug delivery system. It is discovered that stable amide coupling of doxorubicin (DOX) tohyaluronan (HA) shows dose dependent cytotoxicity to CD44 positive human coloncancer cells (HCT116) as compared to human breast cancer cells(MCF-7) and mouse fibroblast cells (NIH-3T3), which express less CD44 receptor. This direct conjugation approach is an easy scalable strategy that could be adopted to design innocuous anti-tumor nanoparticle formulations.

Hyaluronidases and their inhibitors in the serum of colorectal carcinoma patients

Colorectal cancer is the third most commonly diagnosed type of cancer. Hyaluronan is involved in this malignancy. Moreover, hyaluronidases - its degrading enzymes - display controversial roles regarding their involvement in tumor development. HYAL-1 is the major tumor derived hyaluronidase. The aim of the study was the determination and evaluation of hyaluronidase levels in serum of colorectal cancer patients, before and after surgery, with a view to assessing its potential role as a tumor marker for recurrence. By zymography and Western blotting, it was confirmed that HYAL-1 was the only hyaluronidase present in samples. Quantification of its activity indicated a statistically significant decrease in samples seven days postoperatively, compared with the respective ones before surgery. HYAL-1 levels before surgery were significantly reduced in comparison with healthy samples and samples one year postoperatively. Hyaluronidase inhibitor activity was demonstrated under mild alkaline conditions via reverse zymography. A statistically significant increase was observed in samples seven days postoperatively, when compared with samples before surgery. HYAL-1 levels in sera of colorectal cancer patients were lower than those of healthy population, possibly because of the local accumulation of the enzyme in tumor microenvironment. A gradual elevation up to one year postoperatively to reach healthy levels might indicate a role of HYAL-1 levels in cancer.

Low cholesterol triggers membrane microdomain-dependent CD44 shedding and suppresses tumor cell migration

CD44 is a cell surface adhesion molecule for hyaluronan and is implicated in tumor invasion and metastasis. Proteolytic cleavage of CD44 plays a critical role in the migration of tumor cells and is regulated by factors present in the tumor microenvironment, such as hyaluronan oligosaccharides and epidermal growth factor. However, molecular mechanisms underlying the proteolytic cleavage on membranes remain poorly understood. In this study, we demonstrated that cholesterol depletion with methyl-β-cyclodextrin, which disintegrates membrane lipid rafts, enhances CD44 shedding mediated by a disintegrin and metalloproteinase 10 (ADAM10) and that cholesterol depletion disorders CD44 localization to the lipid raft. We also evaluated the effect of long term cholesterol reduction using a statin agent and demonstrated that statin enhances CD44 shedding and suppresses tumor cell migration on a hyaluronan-coated substrate. Our results indicate that membrane lipid organization regulates CD44 shedding and propose a possible molecular mechanism by which cholesterol reduction might be effective for preventing and treating the progression of malignant tumors.

How hyaluronan-protein complexes modulate the hyaluronidase activity: the model

Hyaluronan (HA) is the substrate of hyaluronidase (HAase). In addition, HA is able to form electrostatic complexes with many proteins, including HAase. Experiments have shown the strong inhibition of the HA hydrolysis catalyzed by HAase when performed at low HAase over HA concentration ratio and under low ionic strength conditions. Non-catalytic P proteins are able to compete with HAase to form electrostatic complexes with HA and thus to modulate HAase activity. We have modeled the HA-HAase-P system by considering the competition between the two complex equilibria HA-P and HA-HAase, the Michaelis-Menten type behavior of HAase, and the non-activity of the electrostatically complexed HAase. Simulations performed by introducing experimental data produce a theoretical behavior similar to the experimental one, including all the atypical phenomena observed: substrate-dependence, enzyme-dependence and protein-dependence of HAase. This shows that our assumptions are sufficient to explain the behavior of the system and allow us to estimate unknown parameters and suggest new developments.

Platelet-derived hyaluronidase 2 cleaves hyaluronan into fragments that trigger monocyte-mediated production of proinflammatory cytokines

Hyaluronan (HA) occurs in the body as a large, hydrating, space-filling, carbohydrate polymer in the extracellular matrix; it has both anti-angiogenic and immunosuppressive properties. Cleavage of HA results in the generation of variably sized fragments that stimulate multiple angiogenic and inflammatory responses in a size-specific manner. In this study, we report that platelets, as well as their megakaryocyte precursors, are unusual among somatic cells in that they contain only hyaluronidase 2 (HYAL2) but not HYAL1. Platelet HYAL2 is sufficient to cleave HA into fragments that are specific for inflammatory and angiogenic signaling; this process occurs in the absence of HYAL1, which is necessary in all other tissues to perform further HA degradation. Platelets can bind to HA, some of which derives from the stressed microvessel endothelial cell surface. Platelet-derived HYAL2 cleaves HA into fragments that stimulate mononuclear leukocytes in the immediate microenvironment to produce proinflammatory cytokines, including interleukin-6 and interleukin-8. Platelets, thus, are not only involved in hemostasis, the earliest step in wound healing, but are also important in the signaling of subsequent inflammatory and angiogenic steps. We hypothesize that aberrations in these sequential steps can promote chronic inflammation, as found in inflammatory bowel disease. The platelet may thus provide an interface between acute and chronic inflammation, wound healing, and their subsequent fibrotic responses.

Hyaluronidases in cancer biology

Hyaluronan is a megadalton glycosaminoglycan polymer critical for maintaining the integrity of the extracellular matrix. It can exist in a protein-bound state with aggregating proteoglycans, where it expands the extracellular matrix and modulates cell-cell interactions. It also exists in lower molecular weight forms that participate in a myriad of biological functions. It is unique in that much of it is degraded within hours of its synthesis. High molecular weight hyaluronan, a reflection of intact healthy tissues, is normally produced by hyaluronan synthases at the plasma membrane. It is catabolized by the action of an extracellular plasma membrane-tethered hyaluronidase that is coordinated with intracellular lysosomal hyaluronidases and exoglycosidases. This occurs in local tissues and lymph, with the remainder being cleared by the sinusoidal liver endothelium upon entering the vascular compartment. Elevated extracellular levels of hyaluronan and its partially catabolized oligomers are found in certain malignancies, potentially due to decoupled synthesis and degradation. Furthermore, partially depolymerized hyaluronan in the extracellular environment may have properties not found in the multivalent high molecular weight polymer in malignancies. Functional perturbations of hyaluronan synthesis and degradation have revealed active roles of the synthases and hyaluronidases in epithelial mesenchymal conversion, stroma and vascular formation, interstitial fluid pressure and chemosensitivity. While at least three confirmed hyaluronidases exist in the human genome (HYAL1, HYALl2 and PH20), functional perturbation of these genes in mice have failed to identify a simple linear catabolic circuit. The family of enzymes responsible for the synthesis and degradation of hyaluronan are being characterized. The fragmented forms of hyaluronan, largely a sign of cellular distress, occur in abundance in many malignancies. These small hyaluronan oligomers are assumed to be largely a result of hyaluronidase activity. Precisely how particular-sized fragments are generated and maintained is not known. Presumably, hyaluronan-binding proteins, in addition to the proteoglycans, participate in this process. Hyaluronidase inhibitors are now recognized, as well as growth factors that enhance the synthetic enzymes. A complete understanding of the anabolic and catabolic systems for hyaluronan may provide new dimensions into our understanding of cancer progression, as well as new opportunities for therapeutic intervention.

The many ways to cleave hyaluronan

Hyaluronan is being used increasingly as a component of artificial matrices and in bioengineering for tissue scaffolding. The length of hyaluronan polymer chains is now recognized as informational, involving a wide variety of size-specific functions. Inadvertent scission of hyaluronan can occur during the process of preparation. On the other hand, certain size-specific hyaluronan fragments may be desirable, endowing the finished bioengineered product with specific properties. In this review, the vast arrays of reactions that cause scission of hyaluronan polymers is presented, including those on an enzymatic, free radical, and chemical basis.

The magic glue hyaluronan and its eraser hyaluronidase: a biological overview

Hyaluronan (HA) is a multifunctional high molecular weight polysaccharide found throughout the animal kingdom, especially in the extracellular matrix (ECM) of soft connective tissues. HA is thought to participate in many biological processes, and its level is markedly elevated during embryogenesis, cell migration, wound healing, malignant transformation, and tissue turnover. The enzymes that degrade HA, hyaluronidases (HAases) are expressed both in prokaryotes and eukaryotes. These enzymes are known to be involved in physiological and pathological processes ranging from fertilization to aging. Hyaluronidase-mediated degradation of HA increases the permeability of connective tissues and decreases the viscosity of body fluids and is also involved in bacterial pathogenesis, the spread of toxins and venoms, acrosomal reaction/ovum fertilization, and cancer progression. Furthermore, these enzymes may promote direct contact between pathogens and the host cell surfaces. Depolymerization of HA also adversely affects the role of ECM and impairs its activity as a reservoir of growth factors, cytokines and various enzymes involved in signal transduction. Inhibition of HA degradation therefore may be crucial in reducing disease progression and spread of venom/toxins and bacterial pathogens. Hyaluronidase inhibitors are potent, ubiquitous regulating agents that are involved in maintaining the balance between the anabolism and catabolism of HA. Hyaluronidase inhibitors could also serve as contraceptives and anti-tumor agents and possibly have antibacterial and anti-venom/toxin activities. Additionally, these molecules can be used as pharmacological tools to study the physiological and pathophysiological role of HA and hyaluronidases.

A glycoprotein from a folk medicinal plant, Withania somnifera, inhibits hyaluronidase activity of snake venoms

Venom hyaluronidases help in rapid spreading of the toxins by destroying the integrity of the extra-cellular matrix of the tissues in the victims. A hyaluronidase inhibitor (WSG) is purified from a folk medicinal plant, Withania somnifera. The glycoprotein inhibited the hyaluronidase activity of cobra (Naja naja) and viper (Daboia russelii) venoms, which was demonstrated by zymogram assay and staining of the skin tissues for differential activity. WSG completely inhibited the activity of the enzyme at a concentration of 1:1 w/w of venom to WSG. Thus we are able to demonstrate that the glycoprotein inhibits hyaluronidase activity of the venoms. External application of the plant extract as an antidote in rural parts of India to snakebite victims appears to have a scientific basis.

Magnetic resonance imaging visualization of hyaluronidase in ovarian carcinoma

Hyaluronan, a high molecular weight, negatively charged polysaccharide, is a major constituent of the extracellular matrix. High molecular weight hyaluronan is antiangiogenic, but its degradation by hyaluronidase generates proangiogenic breakdown products. Thus, by expression of hyaluronidase, cancer cells can tilt the angiogenic balance of their microenvironment. Indeed, hyaluronidase-mediated breakdown of hyaluronan correlates with aggressiveness and invasiveness of ovarian cancer metastasis and with tumor angiogenesis. The goal of this work was to develop a novel smart contrast material for detection of hyaluronidase activity by magnetic resonance imaging (MRI). Gadolinium-diethylenetriaminepentaacetic acid (GdDTPA) covalently linked to hyaluronan on the surface of agarose beads showed attenuated relaxivity. Hyaluronidase, either purified from bovine testes or secreted by ES-2 and OVCAR-3 human epithelial ovarian carcinoma cells, activated the hyaluronan-GdDTPA-beads by rapidly altering the R1 and R2 relaxation rates. The change in relaxation rates was consistent with the different levels of biologically active hyaluronidase secreted by those cells. Hyaluronan-GdDTPA-beads were further used for demonstration of MRI detection of hyaluronidase activity in the proximity of s.c. ES-2 ovarian carcinoma tumors in nude mice. Thus, hyaluronan-GdDTPA-beads could allow noninvasive molecular imaging of hyaluronidase-mediated tilt of the peritumor angiogenic balance.

Hyaluronan metabolism: a major paradox in cancer biology

Paradoxically, both hyaluronan (HA) and hyaluronidases, the enzymes that eliminate HA, can correlate with cancer progression. Levels of HA on the surface of tumor cells are indicators of poor outcome. Certain hyaluronidases, products of tumor suppressor genes eliminated in the course of tumor spread, are used clinically in anti-cancer chemotherapy regimens. Such information would indicate that cancer progression is inhibited by hyaluronidase. Yet progression of certain cancers correlates with levels of hyaluronidase activity. An attempt is made here to understand such apparent contradictions by examining details of HA metabolism. Anabolic and catabolic pathways are comprised of the HA synthases and hyaluronidases, respectively. There are several enzymes that synthesize HA, each under a different control mechanism, generating products of differing polymer size. The hyaluronidases degrade HA in step-wise fashion, the polymer decreasing in size in quantum steps, each size-specific polymer having a different biological activity. Superimposed on these are the potent hyaluronidase inhibitors, about which very little is known. These components of HA metabolism are reviewed here for possible roles in supporting or suppressing malignant transformation, growth, invasion and metastatic spread of tumors. Such a systematic approach may reveal mechanisms used in the course of cancer progression, resolve some of the apparent disparities, render new prognostic markers, and provide new targets for therapeutic intervention.

Hyaluronan catabolism: a new metabolic pathway

A new pathway of intermediary metabolism is described involving the catabolism of hyaluronan. The cell surface hyaluronan receptor, CD44, two hyaluronidases, Hyal-1 and Hyal-2, and two lysosomal enzymes, beta-glucuronidase and beta-N-acetylglucosaminidase, are involved. This metabolic cascade begins in lipid raft invaginations at the cell membrane surface. Degradation of the high-molecular-weight extracellular hyaluronan occurs in a series of discreet steps generating hyaluronan chains of decreasing sizes. The biological functions of the oligomers at each quantum step differ widely, from the space-filling, hydrating, anti-angiogenic, immunosuppressive 10(4)-kDa extracellular polymer, to 20-kDa intermediate polymers that are highly angiogenic, immuno-stimulatory, and inflammatory. This is followed by degradation to small oligomers that can induce heat shock proteins and that are anti-apoptotic. The single sugar products, glucuronic acid and a glucosamine derivative are released from lysosomes to the cytoplasm, where they become available for other metabolic cycles. There are 15 g of hyaluronan in the 70-kg individual, of which 5 g are cycled daily through this pathway. Some of the steps in this catabolic cascade can be commandeered by cancer cells in the process of growth, invasion, and metastatic spread.

The effects of diminazene aceturate and ceftriaxone on ram sperm

Effects of diminazene aceturate and ceftriaxone disodium were evaluated on sperm quality of rams. Daily intramuscular injections of diminazene (6 mg/kg) or ceftriaxone (28.5 mg/kg) were given to each of seven Akkaraman rams assigned per drug for two days. Semen samples were collected from the rams at post-treatment 1, 4, 24, 48, 72, 144, 288 and 336 h and examined for sperm characteristics and hyaluronidase activity. Results showed that use of ceftriaxone and diminazene caused significant (P<0.01) decreases in sperm concentration, volume and motility compared to control group within 288 h post-treatment. In addition, hyaluronidase activity increased significantly (P<0.01) in semen of rams treated with ceftriaxone while remained unchanged in those received diminazene. In conclusion, diminazene aceturate and ceftriaxone disodium did not have any deleterious effect on hyaluronidase enzyme. However, both drugs caused impairment of sperm in rams during the 288 h.

Importance of hyaluronan biosynthesis and degradation in cell differentiation and tumor formation

Hyaluronan is an important connective tissue glycosaminoglycan. Elevated hyaluronan biosynthesis is a common feature during tissue remodeling under both physiological and pathological conditions. Through its interactions with hyaladherins, hyaluronan affects several cellular functions such as cell migration and differentiation. The activities of hyaluronan-synthesizing and -degrading enzymes have been shown to be regulated in response to growth factors. During tumor progression hyaluronan stimulates tumor cell growth and invasiveness. Thus, elucidation of the molecular mechanisms which regulate the activities of hyaluronan-synthesizing and -degrading enzymes during tumor progression is highly desired.

The effects of lincomycin-spectinomycin and sulfamethoxazole-trimethoprim on hyaluronidase activities and sperm characteristics of rams

The effects of lincomycin-spectinomycin and sulfamethoxazole-trimethoprim combinations on the hyaluronidase enzyme of serum and semen and on sperm characteristics in rams were determined. Thirthy-two Akkaraman rams were used. The rams were randomly divided into four groups. Group A and group B were determined as control groups of group C (lincomycin-spectinomycin) and D (sulfamethoxazole-trimethoprim), respectively. Combinations of lincomycin-spectinomycin and sulfamethoxazole-trimethoprim were administered at doses of 15 mg.kg(-1) intramuscularly and 12 mg.kg(-1) body weights orally, respectively. Blood and semen samples were collected at 4, 12, 24, 48, 72, 192 and 384 hr. Semen hyaluronidase activities of rams in group C increased significantly (p<0.001, <0.05) compared with the control group at 24 and 48 hr, respectively. Semen hyaluronidase activities in group D rams also increased significantly (p<0.001) in comparison with the control group at all times except 72 and 384 hr. Serum hyaluronidase activities increased significantly (p<0.01, <0.001) at 24 and 48 hr after treatment of lincomycin-spectinomycin. Additionally, significant (p<0.05, <0.001) increases were detected in the serum hyaluronidase activities of group D at 48 and 72 hr, respectively. No significant correlation was found between serum and semen hyaluronidase activities. Furthermore, significant increases (p<0.05) were observed in the percentages of motile sperm in the rams of group C and D compared with the control groups. The values of sperm concentration and total number of sperm in group C and D rams decreased significantly (p<0.001) in comparison with control groups. No significant correlations were found between the semen hyaluronidase activities and sperm characteristics. In conclusion, these findings show that the combinations of lincomycin-spectinomycin and sulfamethoxazole-trimethoprim do not have any harmful effects on hyaluronidase activities and sperm motility. However, the use of both antibiotic combinations in breeding rams during the ramming season is not advisable due to the decrease of sperm concentration.

Hyaluronan is not elevated in urine or serum in Hutchinson-Gilford Progeria Syndrome

Elevations in urinary hyaluronan have been used as the principal laboratory indicator for diagnosis of Hutchinson-Gilford Progeria Syndrome (HGPS). Previous reports have provided evidence suggesting that children with HGPS have altered hyaluronan metabolism as indicated by a mean 17-fold increase in urinary hyaluronan over normal values. In addition, adults with Werner's syndrome have elevated urinary hyaluronan and even more prominent elevations in serum hyaluronan over age-matched controls. It is not known whether serum hyaluronan is elevated or whether serum hyaluronan levels correlate with urinary hyaluronan levels in children with HGPS. In a large cohort of 19 HGPS patients, we sought to confirm elevations in urinary hyaluronan concentration, to establish whether serum hyaluronan is elevated, to measure the size of urinary hyaluronan, and to determine whether serum or urine hyaluronidase levels are altered. We have analyzed urinary and serum hyaluronan levels in patients with HGPS and control patients (1) by using an enzyme-linked immunosorbent assay (ELISA)-like method in which sample hyaluronan in solution and hyaluronan in solid phase compete for a solution of biotinylated hyaluronan-binding protein, and (2) by fluorophore-assisted carbohydrate electrophoresis. The size of urinary hyaluronan was measured by using Sepharose CL-6B size exclusion chromatography. Serum and urinary hyaluronidases were evaluated quantitatively, by using ELISA, and qualitatively, by using a gel detection method. HGPS patients did not show a significant elevation in either urinary or serum hyaluronan. We detected no difference in the size of urinary hyaluronan between HGPS children and age-matched controls. Serum and urinary hyaluronidase levels were not significantly different in normal and HGPS patients. These studies indicate that neither serum nor urinary hyaluronan concentration is a reliable diagnostic or prognostic marker for HGPS and underscore a difference between adult and childhood progerias.

Mystixin peptides reduce hyaluronan deposition and edema formation

Hyaluronan and its associated water of hydration are the basis of the swelling and edema of acute inflammation. Mystixins are small, synthetic peptides that suppress the acute inflammatory response. Mystixin-7, a prototype of these peptides, has the structure p-anisoyl-Arg-Lys-Leu-Leu-D-Thi-Ile-D-Leu-NH(2). As shown previously by this laboratory, the mystixin-7 peptide inhibits edema formation in vivo following intravenous administration at doses of less than 1.0 mg/kg. Mechanisms by which this peptide might suppress edema were examined here in vitro using cultured cells. Normal human dermal fibroblasts normally secrete large quantities of hyaluronan in response to inflammatory stimuli. Mystixin-7 reduced hyaluronan deposition by up to 80% in such cultures. Stimulation of hyaluronidase activity was observed. Mystixins represent a novel class of anti-inflammatory peptides that suppress the edema associated with inflammation. We propose that stimulation of hyaluronidase activity, with a decrease in net hyaluronan deposition and its associated water of hydration, is among the mechanisms of the anti-inflammatory effect of mystixin peptides.

Hyaluronidase gene profiling and role of hyal-1 overexpression in an orthotopic model of prostate cancer

The mRNA levels of hyal-1, hyal-2, LUCA3 and PH20, the 4 hyaluronidases with demonstrated endoglucosaminidase activity, were extensively profiled in normal and tumor tissues and cell lines, using dot blot analysis and quantitative PCR. In normal tissues, hyal-1, hyal-2 and LUCA3 all showed unique patterns of mRNA expression, but were generally of widespread distribution, whereas PH20 mRNA was restricted to testes. In a small set of breast tumor samples, no elevations in hyal-1, hyal-2 or LUCA3 mRNA were seen. Hyaluronidase activity measured by a novel assay or zymography was also not elevated in sera from a number of breast cancer patients, compared to sera from normal volunteers. In ex vivo xenograft tumor cell lines, however, hyal-1 or hyal-2 mRNA levels were frequently elevated, whereas LUCA3 was only infrequently elevated and PH20 not at all. Two cell lines were engineered to overexpress hyal-1: a breast cancer line (CAL51) and a prostate cancer line (PC3M). Although the in vitro properties of the hyal-1 overexpressing cell lines were indistinguishable from the parental cells, the orthotopic growth of hyal-1 expressing PC3M cells in nu/nu mice resulted in significantly increased numbers of metastases, supportive of a role for hyal-1 in extravasation and metastatic tumor formation in this model of prostate cancer.

Inhibitors of the hyaluronidases

The inhibitors of hyaluronidase present in mammalian sera, first described half a century ago, have remained uncharacterized. Because of increased interest in hyaluronidases and their hyaluronan substrate, a study of these inhibitors was undertaken recently. The predominant serum inhibitor is magnesium-dependent and is eliminated by protease or chondroitinase digestion, and by heat. Kinetics of inhibition are similar against hyaluronidases from testis, snake and bee venom. The inhibitor has no effect on Streptomyces hyaluronidase; indicating inhibition is not through protection of the hyaluronan substrate. Circulating inhibition levels are increased in mice following carbon tetrachloride or interleukin-1 injection, inducers of the acute-phase response. Reverse hyaluronan gel zymography reveals a predominant band of 120 kDa relative molecular size. Additional studies indicate that the inhibitor resembles a member of the Kunitz type inter-alpha-inhibitor family. Inhibition of hyaluronidase activity is observed using purified inter-alpha-inhibitor and is reversed by antibodies specific for inter-alpha-inhibitor. This molecule, found in the hyaluronan-rich cumulus mass surrounding mammalian ova and the pericellular coat of fibroblasts and mesothelial cells, may function to stabilize such matrices by protecting against hyaluronidase degradation. Turnover of circulating hyaluronan is extraordinarily rapid, with a half-life of two to five min. Prompt increases in levels of serum hyaluronan occur in patients with shock, septicemia or massive burns, increases that may be partly attributed to suppression by these acute phase reactants of the constant and rapid rates of hyaluronan degradation by hyaluronidase. A literature survey of other hyaluronidase inhibitors is also presented.

Unmasking a hyaluronan-binding site of the BX(7)B type in the H3 heavy chain of the inter-alpha-inhibitor family

The inter-alpha-inhibitor (I alpha I) family gathers together several plasma protease inhibitors such as I alpha I and pre-alpha-inhibitor (P alpha I) that are variously assembled from a set of polypeptide chain precursors designated H1P to H3P. In addition to their protease inhibitory activity, a major physiological function of I alpha I family members is hyaluronan (HA) binding and HA-dependent stabilization of the extracellular matrix surrounding various cell types. Also, binding of HA to these molecules has been shown to be an important event in tumor cell proliferation and rheumatoid arthritis. However, how HA and I alpha I family members first recognize each other has so far remained elusive. The so-called BX7B domain found in some HA-binding proteins is an HA-binding site in which B represents a basic amino-acid residue and X represents any nonacidic residue. This domain has now been identified in the N-terminal end of H3P that is a precursor of P alpha I. A series of wild-type or mutant recombinant H3P chains produced with a mouse cDNA expressed in Escherichia coli allowed us to demonstrate that this domain binds HA in a noncovalent fashion. Furthermore, unmasking this HA-binding activity required most of H3P to be trimmed off at its C-terminal end. The latter observation was confirmed with a natural, mature H3 chain purified from human plasma. Indeed, a thermolysin-generated, N-terminal fragment of this H3 chain strongly bound HA whereas the intact H3 chain did not. Therefore, in vivo, the HA-binding activity of the mature H3 chain within P alpha I may vary with the folding and/or fragmentation of this protein.

Reverse hyaluronan substrate gel zymography procedure for the detection of hyaluronidase inhibitors

Little is known of the ubiquitous inhibitors of hyaluronidase, molecules that may be important for the deposition of hyaluronan. A reverse hyaluronan-substrate gel procedure is described here that detects such inhibitors, even in crude biological extracts, and is independent of the catalytic mechanism of the target enzyme. Following electrophoresis, hyaluronan-containing gels are incubated in a hyaluronidase solution. Alcian blue-staining bands indicate hyaluronan protected from degradation and the location of hyaluronidase inhibitors. Coordinated use of hyaluronan substrate gel and reverse substrate gel procedures provides estimates of the number and relative molecular sizes of both enzymes and their inhibitors.