Cytotoxic and antioxidant effects of unsaturated hyaluronic acid oligomers

Enzymatically stable unsaturated hyaluronan-derived oligosaccharides with selective cytostatic properties

Hyaluronan, a linear glycosaminoglycan comprising D-N-acetylglucosamine and D-glucuronic acid, is the main component of the extracellular matrix. Its influence on cell proliferation, migration, inflammation, signalling, and other functions, depends heavily on its molecular weight and chemical modification. Unsaturated HA oligosaccharides are available in defined length and purity. Their potential therapeutic utility can be further improved by chemical modification, e. g., reduction. No synthesis of such modified oligosaccharides, either stepwise or by hyaluronan cleavage, has been reported yet. Here we show a three-step synthesis (esterification, depolymerization and reduction) of unsaturated even numbered hyaluronan oligosaccharides with carboxylates and the reducing terminus reduced to an alcohol. Particular oligosaccharides were synthesised. The modified oligosaccharides are not cleaved by mammalian or bacterial hyaluronidase and do not affect the growth of mouse and human fibroblasts. Further, MTT and NRU viability tests showed that they inhibit the growth of human colon carcinoma cells HT-29 by 20-50 % in concentrations 500-1000 μg/mL. Interestingly, this effect takes place regardless of CD44 receptor expression and was not observed with unmodified HA oligosaccharides. These compounds could serve as enzymatically stable building blocks for biologically active substances.

High-Level Extracellular Expression of Hyaluronate Lyase HylP in Bacillus subtilis for Hyaluronan Degradation

Hyaluronate lyase (HA lyase) has potential in the industrial processing of hyaluronan. In this study, HylP, an HA lyase from Streptococcus pyogenes phage (SPB) was successfully expressed in Bacillus subtilis. To improve the extracellular enzyme activity of HylP in B. subtilis, signal peptide engineering systematic optimization was carried out, and cultured it from shake flasks and fermenters, followed by purification, characterization, and analysis of degradation products. The results showed that the replacement of the signal peptide increased the extracellular enzyme activity of HylP from 1.0 × 104 U/mL to 1.86 × 104 U/mL in the shake flask assay, and using a 20 L fermenter in a batch fermentation process, the extracellular enzyme activity achieved the level of 1.07 × 105 U/mL. HylP exhibited significant thermal and pH stability in the temperature range of 40 °C and pH range of 4-8, respectively. The enzyme showed optimum activity at 40 °C and pH 6, with significant activity in the presence of Na+, Mg2+, and Co2+ ions. Degradation analysis showed that HylP efficiently degraded hyaluronan as an endonuclease, releasing unsaturated disaccharides. These comprehensive findings underscore the substantial industrial potential of HylP for hyaluronan processing applications, offering valuable insights into enzyme characterization and optimization of expression for potential industrial utilization.

Magnetically Controlled Hyaluronic Acid-Maghemite Nanocomposites with Embedded Doxorubicin

The controllable delivery of drugs is a key task of pharmacology. For this purpose, a series of polymer composites was synthesized via the cross-linking of hyaluronate and a hyaluronate/polyacrylate mixture with Fe2O3 nanoparticles. The cross-linking imparts magnetic properties to the composites, which are more pronounced for the ternary hyaluronate/polyacrylate/γ-Fe2O3 composites compared with the binary hyaluronate/Fe2O3 composites. When dispersed in water, the composites produce microsized hydrogel particles. Circulation of the ternary microgels in an aqueous solution at a speed of 1.84 cm/s can be stopped using a permanent external magnet with a magnetic flux density of 400 T. The composite hydrogels can absorb the antitumor antibiotic doxorubicin (Dox); the resulting constructs show their cytotoxicity to tumor cells to be comparable to the cytotoxicity of Dox itself. The addition of the hyaluronidase enzyme induces degradation of the binary and ternary microgels down to smaller particles. This study presents prospectives for the preparation of magnetically controlled biodegradable polymer carriers for the encapsulation of bioactive substances.

High-level expression and characterization of a highly active hyaluronate lyase HylC with significant potential in hyaluronan oligosaccharide preparation

Hyaluronate lyases (HA lyases) have been proved to distribute widely among microorganisms, with large potential in hyaluronan processing. Here, a highly active HA lyase HylC from Citrobacter freundii strain Cf1 is reported. HylC was expressed in Escherichia coli BL21(DE3) under the regulation of T7 promoter, and purified to electrophoretic homogeneity for enzymatic characterization, which suggested its suitable thermo- and pH stability under 45 °C and pH rang of 4-8, and high halotolerancy in 1.5 M NaCl. The enzyme exhibited the optimal activity under 37 °C and pH 5.5, and was activated by Ca²⁺, K⁺, Zn²⁺, Ni²⁺ and Li⁺. Analysis of degradation product proved it cleave HA in endolytic manner, releasing unsaturated disaccharides as final product. Then, through optimization of promoter and construction of dual promoter, expression level of HylC improved from 1.10 × 10⁴ U/mL to 2.64 × 10⁴ U/mL on shake-flask level. Finally, through batch fermentation, a highest activity of 2.65×10⁵ U/mL was achieved in a 5-L fermenter. Taken together, this work demonstrates the potential of HylC and its recombinant strain in industrial applications. To our knowledge, the HA lyase production reported in this study was the highest level in literatures to date.

Insights into the source, mechanism and biotechnological applications of hyaluronidases

It has long been found that hyaluronidases exist in a variety of organisms, playing their roles in various biological processes including infection, envenomation and metabolic regulation through degrading hyaluronan. However, exploiting them as a bioresource for specific applications had not been extensively studied until the latest decades. In recent years, new application scenarios have been developed, which extended the field of application, and emphasized the research value of hyaluronidase. This critical review comprehensively summarizes existing studies on hyaluronidase from different source, particularly in their structures, action patterns, and biological functions in human and mammals. Furthermore, we give in-depth insight into the resource mining and protein engineering process of hyaluronidase, as well as strategies for their high-level production, indicating that mixed strategies should be adopted to obtain well-performing hyaluronidase with efficiency. In addition, advances in application of hyaluronidase were summarized and discussed. Finally, prospects for future researches are proposed, highlighting the importance of further investigation into the characteristics of hyaluronidases, and the necessity of investigating their products for the development of their application value.

Metabolite profiling and mechanisms of bioactivity of snake autolysate - A traditional Uzbek medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Aqueous autolysate from the snake Eryx miliaris (SNA) has been used in traditional medicine of Uzbekistan as anti-inflammatory, hepatoprotective and immunomodulatory agent. However, little is known about the chemical composition and its mechanisms of activity.

AIM OF THE STUDY

This is our first attempt to analyse the composition of snake autolysate using gas chromatography with mass spectrometry (GC-MS) and to investigate the mechanisms of anti-inflammatory and hyaluronidase activity of fingerprinted E. miliaris autolysate to support their use in the traditional Uzbek medicine.

MATERIALS AND METHODS

Aqueous autolysate was evaporated and derivatised for GC-MS analysis of metabolites. For quantification, lipids were extracted from autolysate by solvent extraction and derivatised by esterification and silylation. Biological activity was evaluated with lipid peroxidation, cyclooxygenase (COX) inhibition and antihyaluronidase activity tests.

RESULTS

GC-MS analysis of SNA enabled the identification of 27 compounds. Short chain fatty acids (SCFA, 21%), amino acid/derivatives 39% (incl. 2-piperidinone 19%), phenyl (7%), and OH-Phenyl (10%) derivatives covered 77%. Other derivatives (9%) included succinic acid and 3-indole acetic acid). Long chain fatty acids (C₁₆-C₁₈) accounted for 3%. The lipid concentration of SNA was 1.2 mg/mL (0.12%). Three concentration levels (1.0-20.0 μg/mL) did not inhibit COX-1 and COX-2 in vitro and malondialdehyde level was not decreased by SNA in lipid peroxidation model. However, SNA was a potent inhibitor of the hyaluronidase enzyme activity in a dose dependent manner with IC₅₀ = 0.086 mL/mL.

CONCLUSION

The results from GC-MS analyses of SNA lead us to the identification of a wide range of major chemical structures of the metabolites and their derivatives with several categories. Pharmacological studies support the traditional use of SNA and show one of its possible mechanisms of activity via inhibition of hyaluronidase.

Effect of ultrasonic degradation of hyaluronic acid extracted from rooster comb on antioxidant and antiglycation activities

CONTENT

Recently, low-molecular-weight hyaluronic acid (LMWHA) has been reported to have novel features, such as free radical scavenging activities, antioxidant activities and dietary supplements.

OBJECTIVE

In this study, hyaluronic acid (HA) was extracted from rooster comb and LMWHA was obtained by ultrasonic degradation in order to assess their antioxidant and antiglycation activities.

MATERIALS AND METHODS

Molecular weight (Mw) and the content of glucuronic acid (GlcA) were used as the index for comparison of the effect of ultrasonic treatment. The effects on the structure were determined by ultraviolet (UV) spectra and Fourier transform infrared spectra (FTIR). The antioxidant activity was determined by three analytical assays (DPPH, NO and TBARS), and the inhibitory effect against glycated-BSA was also assessed.

RESULTS

The GlcA content of HA and LMWHA was estimated at about 48.6% and 47.3%, respectively. The results demonstrate that ultrasonic irradiation decreases the Mw (1090-181 kDa) and intrinsic viscosity (1550-473 mL/g), which indicate the cleavage of the glycosidic bonds. The FTIR and UV spectra did not significantly change before and after degradation. The IC50 value of HA and LWMHA was 1.43, 0.76 and 0.36 mg/mL and 1.20, 0.89 and 0.17 mg/mL toward DPPH, NO and TBARS, respectively. Likewise LMWHA exhibited significant inhibitory effects on the AGEs formation than HA.

DISCUSSION AND CONCLUSION

The results demonstrated that the ultrasonic irradiation did not damage and change the chemical structure of HA after degradation; furthermore, decreasing Mw and viscosity of LMWHA after degradation may enhance the antioxidant and antiglycation activity.

Improvement Production of Hyaluronic Acid by Streptococcus zooepidemicus in Sugarcane Molasses

Microbial hyaluronic acid (HA) production has been preferred rather than extraction from animal tissue for medical and cosmetic applications. In this context, to obtain an economically competitive HA production by Streptococcus zooepidemicus, culture conditions were studied to improve the polymer production in sugarcane molasses. The highest HA production by S. zooepidemicus ATCC 39920 achieved was 2.825 g. L^-1 in a 4.5 L bioreactor with controlled pH (8.0) and medium containing molasses (85.35 g.L^-1 total sugar) pretreated with activated charcoal and yeast extract (50 g.L^-1). The HA produced exhibited a high molecular weight of 1.35 × 10³ kDa and the DPPH radical scavenging activity of the polymer at 1 g.L^-1 was 41 %. The FTIR and UV-Vis spectra showed no substantial differences in the spectral pattern between produced and standard HA. This study is a promising strategy for sugarcane molasses application by producing high value-added products such as hyaluronic acid.

Hyaluronan Upregulates Mitochondrial Biogenesis and Reduces Adenoside Triphosphate Production for Efficient Mitochondrial Function in Slow-Proliferating Human Mesenchymal Stem Cells

Hyaluronan-coated surfaces preserve the proliferation and differentiation potential of mesenchymal stem cells by prolonging their G1-phase transit, which maintains cells in a slow-proliferative mode. Mitochondria are known to play a crucial role in stem cell self-renewal and differentiation. In this study, for the first time, the metabolic mechanism underlying the hyaluronan-regulated slow-proliferative maintenance of stem cells was investigated by evaluating mitochondrial functions. Human placenta-derived mesenchymal stem cells (PDMSCs) cultured on hyaluronan-coated surfaces at 0.5, 3.0, 5.0, and 30 µg/cm² were found to have an average 58% higher mitochondrial mass and an increase in mitochondrial DNA copy number compared to noncoated tissue culture surfaces (control), as well as a threefold increase in the gene expression of the mitochondrial biogenesis-related gene PGC-1α. Increase in mitochondrial biogenesis led to a hyaluronan dose-dependent increase in mitochondrial membrane potential, ATP content, and oxygen consumption rate, with reactive oxygen species levels shown to be at least three times lower compared to the control. Although hyaluronan seemed to favor mitochondrial function, cell entry into a hyaluronan-regulated slow-proliferative mode led to a fivefold reduction in ATP production and coupling efficiency levels. Together, these results suggest that hyaluronan-coated surfaces influence the metabolic proliferative state of stem cells by upregulating mitochondrial biogenesis and function with controlled ATP production. This more efficiently meets the energy requirements of slow-proliferating PDMSCs. A clear understanding of the metabolic mechanism induced by hyaluronan in stem cells will allow future applications that may overcome the current limitations faced in stem cell culture. Stem Cells 2016;34:2512-2524.

Carbonaceous materials passivation on amine functionalized magnetic nanoparticles and its application for metal affinity isolation of recombinant protein

Magnetic nanoparticles (MNPs) with an amine functionalized surface (MH) were passivated with carbonaceous materials (MH@C) by carbonization of glucose under hydrothermal reaction conditions. The carboxylate groups in carbonaceous shell could be enriched to 0.285 mmol/g when acrylic acid was added as a functional monomer in the carbonization reaction (MH@C-Ac). The carbonaceous shell not only protected the magnetic core from acidic erosion but also showed a high adsorption capacity toward Ni(2+) ion. The Ni(2+) ion complexed on MH@C and MH@C-Ac could specifically isolate 6×His tagged recombinant proteins from crude bacterial extracts via metal affinity interaction. The superparamagnetic property facilitates the easy retrieval of the carbonaceous material passivated MNPs from the viscous proteins solutions. Recombinant green fluorescence protein (GFP) and hyaluronic acid (HA) lyase of 9.4 mg and 2.3 mg could be isolated by 1 g of MH@C-Ac-Ni, respectively.

Antioxidant acitivity of low molecular weight hyaluronic acid

Two polysaccharides, low molecular weight hyaluronic acid-1 (LMWHA-1) and LMWHA-2, with their molecular weight of 1.45×10(5) and 4.52×10(4)Da, respectively, were prepared from high molecular weight hyaluronic acid (HA,1.05×10(6)Da). LMWHA-1, LMWHA-2 and HA were studied for their antioxidant activities. In vitro antioxidant assay, LMWHA showed strong inhibition of lipid peroxidation and scavenging activities of hydroxyl radical, moderate 1,1-diphenyl-2-picryldydrazyl radical and superoxide anion scavenging activity. In addition, the LMWHA-1 exhibited much stronger antioxidant activity than LMWHA-2 and HA. For antioxidant testing in vivo, LMWHA-1, LMWHA-2 and HA were orally administrated over a period of 7days in a cyclophosphamide(CY) induced immunosuppressed mice model. As results, administration of LMWHA was able to overcome CY-induced immunosuppression and significantly raised the activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and total antioxidant capacity (TAOC) in immunosuppressed mice. The results showed that the LMWHA, possessing pronounced free radical scavenging and antioxidant activities.