Increased hyaluronan by naked mole-rat Has2 improves healthspan in mice

Abundant high-molecular-mass hyaluronic acid (HMM-HA) contributes to cancer resistance and possibly to the longevity of the longest-lived rodent-the naked mole-rat1,2. To study whether the benefits of HMM-HA could be transferred to other animal species, we generated a transgenic mouse overexpressing naked mole-rat hyaluronic acid synthase 2 gene (nmrHas2). nmrHas2 mice showed an increase in hyaluronan levels in several tissues, and a lower incidence of spontaneous and induced cancer, extended lifespan and improved healthspan. The transcriptome signature of nmrHas2 mice shifted towards that of longer-lived species. The most notable change observed in nmrHas2 mice was attenuated inflammation across multiple tissues. HMM-HA reduced inflammation through several pathways, including a direct immunoregulatory effect on immune cells, protection from oxidative stress and improved gut barrier function during ageing. These beneficial effects were conferred by HMM-HA and were not specific to the nmrHas2 gene. These findings demonstrate that the longevity mechanism that evolved in the naked mole-rat can be exported to other species, and open new paths for using HMM-HA to improve lifespan and healthspan.

Downstream process intensification for biotechnologically generated hyaluronic acid: Purification and characterization

Hyaluronic acid (HA), an anionic, non-sulfated glycosaminoglycan, has several clinical applications. This study examines several downstream methods for purifying HA with maximum recovery and purity. Following the fermentation of Streptococcus zooepidemicus MTCC 3523 to produce HA, the broth was thoroughly purified to separate cell debris and insoluble impurities using a filtration procedure and a variety of adsorbents for soluble impurities. Nucleic acids, proteins with high molecular weight, were successfully removed from the broth using activated carbons and XAD-7 resins. In contrast, insoluble and low molecular weight impurities were removed using diafiltration, with HA recovery of 79.16% and purity close to 90%. Different analytical and characterization procedures such as Fourier transform-infrared spectroscopy, X-ray diffraction, nuclear magnetic resonance, and scanning electron microscopy validated the presence, purity, and structure of HA. Microbial HA showed activity in tests for 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical-scavenging (4.87 ± 0.45 kmol TE/g), total antioxidant capacity (13.32 ± 0.52%), hydroxyl radical-scavenging (32.03 ± 0.12%), and reducing power (24.85 ± 0.45%). The outcomes showed that the precipitation, adsorption, and diafiltration processes are suitable for extracting HA from a fermented broth under the chosen operating conditions. The HA produced was of pharmaceutical grade for non-injectable applications.

3'UTR shortening of HAS2 promotes hyaluronan hyper-synthesis and bioenergetic dysfunction in pulmonary hypertension

Pulmonary hypertension (PH) comprises a diverse group of disorders that share a common pathway of pulmonary vascular remodeling leading to right ventricular failure. Development of anti-remodeling strategies is an emerging frontier in PH therapeutics that requires a greater understanding of the interactions between vascular wall cells and their extracellular matrices. The ubiquitous matrix glycan, hyaluronan (HA), is markedly elevated in lungs from patients and experimental models with PH. Herein, we identified HA synthase-2 (HAS2) in the pulmonary artery smooth muscle cell (PASMC) layer as a predominant locus of HA dysregulation. HA upregulation involves depletion of NUDT21, a master regulator of alternative polyadenylation, resulting in 3'UTR shortening and hyper-expression of HAS2. The ensuing increase of HAS2 and hyper-synthesis of HA promoted bioenergetic dysfunction of PASMC characterized by impaired mitochondrial oxidative capacity and a glycolytic shift. The resulting HA accumulation stimulated pro-remodeling phenotypes such as cell proliferation, migration, apoptosis-resistance, and stimulated pulmonary artery contractility. Transgenic mice, mimicking HAS2 hyper-synthesis in smooth muscle cells, developed spontaneous PH, whereas targeted deletion of HAS2 prevented experimental PH. Pharmacological blockade of HAS2 restored normal bioenergetics in PASMC, ameliorated cell remodeling phenotypes, and reversed experimental PH in vivo. In summary, our results uncover a novel mechanism of HA hyper-synthesis and downstream effects on pulmonary vascular cell metabolism and remodeling.

Heterologous production of hyaluronic acid in Nicotiana tabacum hairy roots expressing a human hyaluronan synthase 2

Hyaluronic acid (HA), a unique polysaccharide with excellent Physico-chemical properties, is broadly used in pharmaceutical, biomedical, and cosmetic fields. It is widely present in all vertebrates, certain bacterial strains, and even viruses while it is not found in plants, fungi, and insects. HA is naturally synthesized by a class of integral membrane proteins called Hyaluronic acid synthase (HAS). Thus far, industrial production of HA is carried out based on either extraction from animal sources or large-scale microbial fermentation. The major drawbacks to using these systems are contamination with pathogens and microbial toxins. Recently, the production of HA through recombinant systems has received considerable attention. Plants are eco-friendly ideal expression systems for biopharmaceuticals production. In this study, the optimized human hyaluronic acid synthase2 (hHAS2) sequence was transformed into Nicotiana tabacum using Agrobacterium rhizogenes. The highest rhHAS2 concentration of 65.72 ng/kg (wet weight) in transgenic tobacco hairy roots was measured by the human HAS2 ELISA kit. The HA production in the transgenic hairy roots was verified by scanning electron microscope (SEM) and quantified by the HA ELISA kit. The DPPH radical scavenging activity of HA with the highest concentration of 0.56 g/kg (wet weight) showed a maximum activity of 46%. Gel Permeation Chromatography (GPC) analyses revealed the high molecular weight HA (HMW-HA) with about > 0.8 MDa.

Roles of glomerular endothelial hyaluronan in the development of proteinuria

Vascular endothelial cells are covered with glycocalyx comprising heparan sulfate, hyaluronan, chondroitin sulfate, and associated proteins. Glomerular endothelial glycocalyx is involved in protecting against induction of proteinuria and structural damage, but the specific components in glycocalyx that represent therapeutic targets remain unclear. Anti-vascular endothelial growth factor (VEGF) therapy is associated with an increased risk of glomerular endothelial injury. This study investigated whether hyaluronan could provide a therapeutic target to protect against proteinuria. We conducted ex vivo and in vivo experiments to explore the effects of degrading glomerular hyaluronan by administering hyaluronidase and of supplementation with hyaluronan. We investigated hyaluronan expression using biotin-labeled hyaluronan-binding protein (HABP) in human kidney specimens or serum hyaluronan in endothelial injuries under inhibition of VEGF signaling. We directly demonstrated hyaluronan in glomerular endothelial layers using HABP staining. Ex vivo and in vivo experiments showed the development of proteinuria after digestion of hyaluronan in glomerular capillaries. Supplementation with hyaluronan after hyaluronidase treatment suppressed proteinuria. Mice in the in vivo study developed albuminuria after intraperitoneal injection of hyaluronidase with decreased glomerular hyaluronan and increased serum hyaluronan. In human kidneys with endothelial cell dysfunction and proteinuria due to inhibition of VEGF, glomerular expression of hyaluronan was reduced even in normal-appearing glomeruli. Serum hyaluronan levels were elevated in patients with pre-eclampsia with VEGF signaling inhibition. Our data suggest that hyaluronan itself plays crucial roles in preventing proteinuria and preserving the integrity of endothelial cells. Hyaluronan could provide a therapeutic target for preventing glomerular endothelial glycocalyx damage, including VEGF signaling inhibition.

Initial Identification of UDP-Glucose Dehydrogenase as a Prognostic Marker in Breast Cancer Patients, Which Facilitates Epirubicin Resistance and Regulates Hyaluronan Synthesis in MDA-MB-231 Cells

UDP-glucose-dehydrogenase (UGDH) synthesizes UDP-glucuronic acid. It is involved in epirubicin detoxification and hyaluronan synthesis. This work aimed to evaluate the effect of UGDH knockdown on epirubicin response and hyaluronan metabolism in MDA-MB-231 breast cancer cells. Additionally, the aim was to determine UGDH as a possible prognosis marker in breast cancer. We studied UGDH expression in tumors and adjacent tissue from breast cancer patients. The prognostic value of UGDH was studied using a public Kaplan–Meier plotter. MDA-MB-231 cells were knocked-down for UGDH and treated with epirubicin. Epirubicin-accumulation and apoptosis were analyzed by flow cytometry. Hyaluronan-coated matrix and metabolism were determined. Autophagic-LC3-II was studied by Western blot and confocal microscopy. Epirubicin accumulation increased and apoptosis decreased during UGDH knockdown. Hyaluronan-coated matrix increased and a positive modulation of autophagy was detected. Higher levels of UGDH were correlated with worse prognosis in triple-negative breast cancer patients that received chemotherapy. High expression of UGDH was found in tumoral tissue from HER2^--patients. However, UGDH knockdown contributes to epirubicin resistance, which might be associated with increases in the expression, deposition and catabolism of hyaluronan. The results obtained allowed us to propose UGDH as a new prognostic marker in breast cancer, positively associated with development of epirubicin resistance and modulation of extracellular matrix.

Helix-Loop-Helix Factor Id3 (Inhibitor of Differentiation 3): A Novel Regulator of Hyaluronan-Mediated Adipose Tissue Inflammation

OBJECTIVE

The aim of this study was to unravel mechanisms whereby deficiency of the transcription factor Id3 (inhibitor of differentiation 3) leads to metabolic dysfunction in visceral obesity. We investigated the impact of loss of Id3 on hyaluronic acid (HA) production by the 3 HAS isoenzymes (HA synthases; -1, -2, and -3) and on obesity-induced adipose tissue (AT) accumulation of proinflammatory B cells. Approach and Results: Male Id3-/- mice and respective wild-type littermate controls were fed a 60% high-fat diet for 4 weeks. An increase in inflammatory B2 cells was detected in Id3-/- epididymal AT. HA accumulated in epididymal AT of high-fat diet-fed Id3-/- mice and circulating levels of HA were elevated. Has2 mRNA expression was increased in epididymal AT of Id3-/- mice. Luciferase promoter assays showed that Id3 suppressed Has2 promoter activity, while loss of Id3 stimulated Has2 promoter activity. Functionally, HA strongly promoted B2 cell adhesion in the AT and on cultured vascular smooth muscle cells of Id3-/- mice, an effect sensitive to hyaluronidase.

CONCLUSIONS

Our data demonstrate that loss of Id3 increases Has2 expression in the epididymal AT, thereby promoting HA accumulation. In turn, elevated HA content promotes HA-dependent binding of B2 cells and an increase in the B2 cells in the AT, which contributes to AT inflammation.

Loss of versican and production of hyaluronan in lung epithelial cells are associated with airway inflammation during RSV infection

Airway inflammation is a critical feature of lower respiratory tract infections caused by viruses such as respiratory syncytial virus (RSV). A growing body of literature has demonstrated the importance of extracellular matrix changes such as the accumulation of hyaluronan (HA) and versican in the subepithelial space in promoting airway inflammation; however, whether these factors contribute to airway inflammation during RSV infection remains unknown. To test the hypothesis that RSV infection promotes inflammation via altered HA and versican production, we studied an ex vivo human bronchial epithelial cell (BEC)/human lung fibroblast (HLF) coculture model. RSV infection of BEC/HLF cocultures led to decreased hyaluronidase expression by HLFs, increased accumulation of HA, and enhanced adhesion of U937 cells as would be expected with increased HA. HLF production of versican was not altered following RSV infection; however, BEC production of versican was significantly downregulated following RSV infection. In vivo studies with epithelial-specific versican-deficient mice [SPC-Cre(+) Vcan-/-] demonstrated that RSV infection led to increased HA accumulation compared with control mice, which also coincided with decreased hyaluronidase expression in the lung. SPC-Cre(+) Vcan-/- mice demonstrated enhanced recruitment of monocytes and neutrophils in bronchoalveolar lavage fluid and increased neutrophils in the lung compared with SPC-Cre(-) RSV-infected littermates. Taken together, these data demonstrate that altered extracellular matrix accumulation of HA occurs following RSV infection and may contribute to airway inflammation. In addition, loss of epithelial expression of versican promotes airway inflammation during RSV infection further demonstrating that versican's role in inflammatory regulation is complex and dependent on the microenvironment.

Hyaluronan: Metabolism and Function

As a major polysaccharide component of the extracellular matrix, hyaluronan plays essential roles in the organization of tissue architecture and the regulation of cellular functions, such as cell proliferation and migration, through interactions with cell-surface receptors and binding molecules. Metabolic pathways for biosynthesis and degradation tightly control the turnover rate, concentration, and molecular size of hyaluronan in tissues. Despite the relatively simple chemical composition of this polysaccharide, its wide range of molecular weights mediate diverse functions that depend on molecular size and tissue concentration. Genetic engineering and pharmacological approaches have demonstrated close associations between hyaluronan metabolism and functions in many physiological and pathological events, including morphogenesis, wound healing, and inflammation. Moreover, emerging evidence has suggested that the accumulation of hyaluronan extracellular matrix and fragments due to the altered expression of hyaluronan synthases and hyaluronidases potentiates cancer development and progression by remodeling the tumor microenvironment. In addition to the well-known functions exerted by extracellular hyaluronan, recent metabolomic approaches have also revealed that its synthesis can regulate cellular functions via the reprogramming of cellular metabolism. This review highlights the current advances in knowledge on the biosynthesis and catabolism of hyaluronan and describes the diverse functions associated with hyaluronan metabolism.

Hyaluronic Acid: Redefining Its Role

The discovery of several unexpected complex biological roles of hyaluronic acid (HA) has promoted new research impetus for biologists and, the clinical interest in several fields of medicine, such as ophthalmology, articular pathologies, cutaneous repair, skin remodeling, vascular prosthesis, adipose tissue engineering, nerve reconstruction and cancer therapy. In addition, the great potential of HA in medicine has stimulated the interest of pharmaceutical companies which, by means of new technologies can produce HA and several new derivatives in order to increase both the residence time in a variety of human tissues and the anti-inflammatory properties. Minor chemical modifications of the molecule, such as the esterification with benzyl alcohol (Hyaff-11® biomaterials), have made possible the production of water-insoluble polymers that have been manufactured in various forms: membranes, gauzes, nonwoven meshes, gels, tubes. All these biomaterials are used as wound-covering, anti-adhesive devices and as scaffolds for tissue engineering, such as epidermis, dermis, micro-vascularized skin, cartilage and bone. In this review, the essential biological functions of HA and the applications of its derivatives for pharmaceutical and tissue regeneration purposes are reviewed.

Key Factors for A One-Pot Enzyme Cascade Synthesis of High Molecular Weight Hyaluronic Acid

In the last decades, interest in medical or cosmetic applications of hyaluronic acid (HA) has increased. Size and dispersity are key characteristics of biological function. In contrast to extraction from animal tissue or bacterial fermentation, enzymatic in vitro synthesis is the choice to produce defined HA. Here we present a one-pot enzyme cascade with six enzymes for the synthesis of HA from the cheap monosaccharides glucuronic acid (GlcA) and N-acetylglucosamine (GlcNAc). The combination of two enzyme modules, providing the precursors UDP–GlcA and UDP–GlcNAc, respectively, with hyaluronan synthase from Pasteurella multocida (PmHAS), was optimized to meet the kinetic requirements of PmHAS for high HA productivity and molecular weight. The Mg²⁺ concentration and the pH value were found as key factors. The HA product can be tailored by different conditions: 25 mM Mg²⁺ and 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid (HEPES)-NaOH pH 8 result into an HA product with high M_w HA (1.55 MDa) and low dispersity (1.05). Whereas with 15 mM Mg²⁺ and HEPES–NaOH pH 8.5, we reached the highest HA concentration (2.7 g/L) with a yield of 86.3%. Our comprehensive data set lays the basis for larger scale enzymatic HA synthesis.

Nanotherapy in Joints: Increasing Endogenous Hyaluronan Production by Delivering Hyaluronan Synthase 2

Osteoarthritis (OA) is a common joint degenerative disease that causes pain, joint damage, and dysfunction. External hyaluronic acid (HA) supplement is a common method for the management of osteoarthritis which requires multi-injections. It is demonstrated that biodegradable mesoporous silica nanoparticles successfully deliver an enzyme, hyaluronan synthase type 2 (HAS2), into synoviocytes from the temporomandibular joint (TMJ) and generate endogenous HA with high molecular weights. In a rat TMJ osteoarthritis inflammation model, this strategy promotes endogenous HA production and inhibits the synovial inflammation of OA for more than 3 weeks with one-shot administration. Such nanotherapy also helps repairing the bone defects in a rat OA bone defect model.

Hyaluronic Acid Synthesis Contributes to Tissue Damage in Systemic Lupus Erythematosus

Hyaluronic acid (HA), a component of the extracellular matrix, is the ligand for CD44 and has been implicated in the pathogenesis of kidney inflammation in patients with systemic lupus erythematosus (SLE), but its direct role and mechanism of action have not been studied. Here we show that administration of hymecromone (4-Methylumbelliferone, 4-MU), an HA synthesis inhibitor, to lupus-prone mice suppressed dramatically lupus-related pathology. Interestingly, 4-MU stopped the appearance of disease when administered prior to its onset and inhibited the progression of disease when administered after its appearance. Inhibition of HA synthesis in vivo reduced tissue damage and the number of intrarenal lymphoid cell infiltrates including double negative CD3+CD4-CD8- T cells which are known to be involved in the pathogenesis of SLE. Exposure of human peripheral blood mononuclear cells to HA in vitro increased the generation of CD3+CD4-CD8- T cells through a mechanism involving Rho-associated kinase. Our results signify the importance of the HA-rich tissue microenvironment in the activation of lymphocytes to cause tissue damage in SLE and suggest the consideration of inhibition of HA synthesis to treat patients.

TGF-β1 promotes hyaluronan synthesis by upregulating hyaluronan synthase 2 expression in human granulosa-lutein cells

Hyaluronan serves as a structural component of ovarian follicles, and hyaluronan-mediated signaling cascades lead to follicular development, oocyte maturation, and ovulation. Transforming growth factor-β (TGF-β1) is highly expressed in human oocytes and granulosa cells and involved in the regulation of follicular development and ovulation. Previous studies have shown the imperative role for TGF-β signaling in the regulation of hyaluronan-mediated cumulus expansion and ovulation in human granulosa-lutein (hGL) cells. However, the detailed underlying molecular mechanisms by which TGF-β regulates the synthesis of hyaluronan in hGL cells are not fully elucidated. Using both primary and immortalized hGL cells as study models, we provide the first data showing that TGF-β1 significantly promoted the synthesis of hyaluronan by upregulating the expression of hyaluronan synthase 2 in these cells. Additionally, using dual inhibition approaches, we show that the TGF-β type II (TβRII) receptor and TGF-β type I (ALK5) receptor are functional receptors that mediate stimulatory effects in response to TGF-β1. Moreover, we found that the canonical SMAD2/SMAD3-SMAD4 signaling pathway is the principal intracellular signaling pathway that upregulates the expressionhyaluronan synthase and subsequent hyaluronan synthesis. Notably, we showed that SNAIL transcription factor is a critical molecule mediating the TGF-β signaling, which contributes to the increase in hyaluronan synthesis. These results of our in vitro studies suggest that intraovarian TGF-β1 plays a functional role in the local regulation of hyaluronan synthesis in hGL cells.

Oral Intake of Collagen Peptide Attenuates Ultraviolet B Irradiation-Induced Skin Dehydration In Vivo by Regulating Hyaluronic Acid Synthesis

Collagen peptide (CP) has beneficial effects on functions of the skin, such as skin barrier function and skin elasticity, in vivo. However, there are few studies investigating the mechanism underlying the potential effects of CP in skin epidermal moisturization after ultraviolet B (UVB) irradiation. In this study, we examined whether orally-administered CP affects the loss of skin hydration induced by UVB irradiation in hairless mice. SKH-1 hairless mice were orally administered CP at two doses (500 and 1000 mg/kg) for nine weeks, and the dorsal skin was exposed to UVB. The potential effects of CP were evaluated by measuring the transepidermal water loss (TEWL), skin hydration, wrinkle formation, and hyaluronic acid expression in the dorsal mice skin. We found that oral administration of CP increased skin hydration and decreased wrinkle formation compared to the UVB-irradiated group. Treatment of CP increased the mRNA and protein expression of hyaluronic acid synthases (HAS-1 and -2) concomitant with an increased hyaluronic acid production in skin tissue. The expression of hyaluronidase (HYAL-1 and 2) mRNA was downregulated in the CP-treated group. In addition, the protein expression of skin-hydrating factors, filaggrin and involucrin, was upregulated via oral administration of CP. In summary, these results show that oral administration of CP increases hyaluronic acid levels, which decreases during UVB photoaging. Therefore, we suggest that CP can be used as a nutricosmetic ingredient with potential effects on UVB-induced skin dehydration and moisture loss in addition to wrinkle formation.

Distinct reaction mechanisms for hyaluronan biosynthesis in different kingdoms of life

Hyaluronan (HA) is an acidic high molecular weight cell surface polysaccharide ubiquitously expressed by vertebrates, some pathogenic bacteria and even viruses. HA modulates many essential physiological processes and is implicated in numerous pathological conditions ranging from autoimmune diseases to cancer. In various pathogens, HA functions as a non-immunogenic surface polymer that reduces host immune responses. It is a linear polymer of strictly alternating glucuronic acid and N-acetylglucosamine units synthesized by HA synthase (HAS), a membrane-embedded family-2 glycosyltransferase. The enzyme synthesizes HA and secretes the polymer through a channel formed by its own membrane-integrated domain. To reveal how HAS achieves these tasks, we determined the biologically functional units of bacterial and viral HAS in a lipid bilayer environment by co-immunoprecipitation, single molecule fluorescence photobleaching, and site-specific cross-linking analyses. Our results demonstrate that bacterial HAS functions as an obligate homo-dimer with two functional HAS copies required for catalytic activity. In contrast, the viral enzyme, closely related to vertebrate HAS, functions as a monomer. Using site-specific cross-linking, we identify the dimer interface of bacterial HAS and show that the enzyme uses a reaction mechanism distinct from viral HAS that necessitates a dimeric assembly.

Effect of bone morphogenetic protein-15 on gonadotropin-stimulated synthesis of hyaluronan and progesterone in porcine ovarian follicle

Bone morphogenetic protein-15 (BMP-15), an oocyte-derived growth factor, has been shown to play integral roles in regulation of ovarian follicular function in mammals. Despite the recognition of the physiological importance of the BMP system in regulation of gonadotropin action in the ovary, molecular mechanisms of BMP-15 effect on oocyte and somatic follicular cell functions remain poorly understood. The objective of this study was to determine the effect of BMP-15 on the FSH/LH-stimulated synthesis of hyaluronan (HA) by oocyte cumulus complexes (OCC) and progesterone by OCC and granulosa cells (GC) in the presence or absence of serum using primary porcine cultures. In addition, the effect of BMP-15 on oocyte maturation- and steroidogenesis-related transcripts after 4, 8, 16, and 24 hours of cultivation was evaluated using real-time RT-PCR. We demonstrated that the FSH/LH-induced cumulus expansion was accompanied by a significant increase in CD44, PTGS2, CYP11A1 (at 4 h) and AREG, HAS2, TNFAIP6, STAR (at 8 h) mRNAs. While FSH/LH-stimulated total HA synthesis by OCC was not affected by BMP-15 in serum-supplemented medium, its retention within the complex was significantly increased after the action of BMP-15 in comparison to FSH/LH alone (P < 0.001; 65% versus 35%, respectively). Moreover, we detected a significant increase in the expression of AREG and TNFAIP6 (both at 16 h), and CYP11A1 (at 24 h) in FSH/LH-stimulated OCC due to the action of BMP-15 compared to complexes cultured only with FSH/LH. In the presence of serum, BMP-15 markedly increased FSH/LH-stimulated progesterone secretion by OCC (about 69%) and induced a significant decrease in FSH/LH-induced progesterone release by GC (about 35%) compared to FSH/LH alone. The present results indicate that the addition of BMP-15 to the gonadotropin-stimulated OCC cultured in serum-supplemented medium might improve oocyte-cumulus maturation.

Enhanced Biosynthesis of Hyaluronic Acid Using Engineered Corynebacterium glutamicum Via Metabolic Pathway Regulation

Hyaluronic acid (HA) is a polysaccharide used in many industries such as medicine, surgery, cosmetics, and food. To avoid potential pathogenicity caused by its native producer, Streptococcus, efforts have been made to create a recombinant host for HA production. In this work, a GRAS (generally recognized as safe) strain, Corynebacterium glutamicum, is engineered for enhanced biosynthesis of HA via metabolic pathway regulation. Five enzymes (HasA-HasE) involved in the HA biosynthetic pathway are highlighted, and eight diverse operon combinations, including HasA, HasAB, HasAC, HasAD, HasAE, HasABC, HasABD, and HasABE, are compared. HasAB and HasABC are found to be optimal for HA biosynthesis in C. glutamicum. To meet the energy demand for HA synthesis, the metabolic pathway that produces lactate is blocked by knocking out the lactate dehydrogenase (LDH) gene using single crossover homologous recombination. Engineered C. glutamicum/Δldh-AB is superior and had a significantly higher HA titer than C. glutamicum/Δldh-ABC. Batch and fed-batch cultures of C. glutamicum/Δldh-AB are performed in a 5-L fermenter. Using glucose feeding, the maximum HA titer reached 21.6 g L^-1 , more than threefolds of that of the wild-type Streptococcus. This work provides an efficient, safe, and novel recombinant HA producer, C. glutamicum/Δldh-AB, via metabolic pathway regulation.

[Effects and Its Mechanism of IGF-1R on the Synthesis of Hyaluronic Acid in Orbital Fibroblasts of Thyroid Associated Ophthalmopathy]

OBJECTIVE

To explore the effects of insulin-like growth factor1 (IGF1) receptor (IGF1R) on the synthesis of hyaluronic acid (HA) in orbital fibroblasts of thyroid associated ophthalmopathy (TAO) and its signal pathway.

METHODS

Orbital fibroblasts were harvested from TAO ( n=19) and normal control ( n=5),then were primary cultured and treated with recombinant human IGF1 in different concentrations. Before the treatment of IGF1,the cells were pretreated respectively with 1H7,LY294002 or AKT inhibitor Ⅳ for 24 h. The production of HA was measured using a commercial ELISA kit,and the synthesis of PI3K,Akt and pAkt was measured by Western blot.

RESULTS

Along with the increase of recombinant human IGF1 concentration,the synthesis of HA by TAO orbital fibroblasts were increased as well,the synthesis of HA peaked at the concentration of 10 nmol/L in IGF1 in TAO group ( P<0.01). Compared with the normal control,orbital fibroblasts from TAO had the synthesis of HA increased after the treatment of IGF1 ( P<0.01). The pretreatment of 1H7 or AKT inhibitor Ⅳ significantly decreased the HA concentration in culture media ( P<0.01),while the decrease of HA synthesis in the group pretreated with LY294002 was not statistically significant ( P=0.390). IGF1 treatment increased the level of pAkt expression,but it seems no effects on PI3K and Akt expression. 1H7 and LY294002 decreased the expression of PI3K and pAkt protein,but no obvious inhibitory effect on total Akt protein. Akt inhibitor Ⅳ decreased the expression of PI3K,Akt and pAkt.

CONCLUSION

The synthesis of HA by orbital fibroblasts could be increased in TAO,which may partially via phosphoinositide 3kinase/Akt pathway.

The Combined Influence of Hydrogel Stiffness and Matrix-Bound Hyaluronic Acid Content on Glioblastoma Invasion

Glioblastoma (GBM) is the most common and lethal form of brain cancer. Its high mortality is associated with its aggressive invasion throughout the brain. The heterogeneity of stiffness and hyaluronic acid (HA) content within the brain makes it difficult to study invasion in vivo. A dextran-bead assay is employed to quantify GBM invasion within HA-functionalized gelatin hydrogels. Using a library of stiffness-matched hydrogels with variable levels of matrix-bound HA, it is reported that U251 GBM invasion is enhanced in softer hydrogels but reduced in the presence of matrix-bound HA. Inhibiting HA-CD44 interactions reduces invasion, even in hydrogels lacking matrix-bound HA. Analysis of HA biosynthesis suggests that GBM cells compensate for a lack of matrix-bound HA by producing soluble HA to stimulate invasion. Together, a robust method is showed to quantify GBM invasion over long culture times to reveal the coordinated effect of matrix stiffness, immobilized HA, and compensatory HA production on GBM invasion.

Topical Erythropoietin Treatment Accelerates the Healing of Cutaneous Burn Wounds in Diabetic Pigs Through an Aquaporin-3-Dependent Mechanism

We have previously reported that the topical application of erythropoietin (EPO) to cutaneous wounds in rats and mice with experimentally induced diabetes accelerates their healing by stimulating angiogenesis, reepithelialization, and collagen deposition, and by suppressing the inflammatory response and apoptosis. Aquaporins (AQPs) are integral membrane proteins whose function is to regulate intracellular fluid hemostasis by enabling the transport of water and glycerol. AQP3 is the AQP that is expressed in the skin where it facilitates cell migration and proliferation and re-epithelialization during wound healing. In this report, we provide the results of an investigation that examined the contribution of AQP3 to the mechanism of EPO action on the healing of burn wounds in the skin of pigs with experimentally induced type 1 diabetes. We found that topical EPO treatment of the burns accelerated their healing through an AQP3-dependent mechanism that activates angiogenesis, triggers collagen and hyaluronic acid synthesis and the formation of the extracellular matrix (ECM), and stimulates reepithelialization by keratinocytes. We also found that incorporating fibronectin, a crucial constituent of the ECM, into the topical EPO-containing gel, can potentiate the accelerating action of EPO on the healing of the burn injury.

Microvasculature of the Mouse Cerebral Cortex Exhibits Increased Accumulation and Synthesis of Hyaluronan With Aging

The microvasculature of the aged brain is less dense and more vulnerable to dysfunction than that of the young brain. Brain microvasculature is supported by its surrounding extracellular matrix, which is comprised largely of hyaluronan (HA). HA is continually degraded into lower molecular weight forms that induce neuroinflammation. We examined HA associated with microvessels (MV) of the cerebral cortex of young (4 months), middle-aged (14 months), and aged (24-26 months) mice. We confirmed that the density of cortical MV decreased with age. Perivascular HA levels increased with age, but there was no age-associated change in HA molecular weight profile. MV isolated from aged cortex had more HA than MV from young cortex. Examination of mechanisms that might account for elevated HA levels with aging showed increased HA synthase 2 (HAS2) mRNA and protein in aged MV relative to young MV. In contrast, mRNAs for HA-degrading hyaluronidases or hyaladherins that mitigate HA degradation showed no changes with age. Corresponding to increased HAS2, aged MV synthesized significantly more HA (of all molecular weight classes) in vitro than young MV. We propose that increased HA synthesis and accumulation in brain MV contributes to neuroinflammation and reduced MV density and function in aging.

The Potential of Triterpenoids from Loquat Leaves (Eriobotrya japonica) for Prevention and Treatment of Skin Disorder

The leaves of loquat (Eriobotrya japonica) possess high medicinal value and have been used as traditional medicines. However, there are no evidence-based studies on the skin-care effects of E. japonica leaves. To explore new biological activities of E. japonica leaves against skin disorder and to gain a better understanding of the chemical components associated with bioactivities, we evaluated 18 triterpenoids from E. japonica leaves on anti-melanogenesis, anti-acne, anti-allergy and anti-aging activities. Our results revealed that eight compounds showed anti-melanogenesis activity, of which ursolic acid (1) and maslinic acid (7) were the most potent with the similar selective index to that of arbutin. Structure–activity relationship and possible mechanism of active compounds were proposed. Twelve compounds exhibited anti-acne effect; ursolic acid (1), maslinic acid (7), corosolic acid (8) and euscaphic acid (12) showed highest activities against P. acnes. Four compounds displayed anti-allergy and anti-inflammatory activity; 3-epicorosolic acid (9) and euscaphic acid (12) showed marked activity against β-hexosaminidase release. Finally, ursolic acid (1), pomolic acid (10), colosolic acid (8) and its methylated derivative (6) exhibited the highest anti-aging activity by stimulating collagen and hyaluronic acid (HA) production. Our findings provide valuable evidence that E. japonica leaves have potential applications as ingredients of function foods or cosmetics for health benefits and a number of triterpenoids may play an important role in these bioactivities.

Effect of platelet reach plasma on fibroblast primary culture: gene expression evaluation

To correct skin imperfections, aesthetic medicine today makes use of injectable dermal fillers that allow filling skin by increasing the volume of soft tissue. Currently, there are many fillers usable for their excellent biocompatibility and low allergic reactions that ensure good results and good compliance. Among these, the most widely used filler is Human Plasma, obtained by centrifugation from patient blood and processed through cycles of centrifugation and heating, until it becomes a gel. In this work, we evaluated the effect of the Plasma on fibroblasts behavior in terms of cell viability, survival, growth and collagen production. To this aim, the expression levels of some adhesion and traction-resistance related genes (COL11A1, ELN, GDF6, IGF1, DSP, ELANE, HAS1, HYAL1, COL1A1 and COL3A1) were analyzed using real time Reverse Transcription-Polymerase Chain Reaction (real time RT-PCR). All genes, except for COL1A1, COL3A1 and COL11A1, were up-regulated after 24 h of treatment. Altogether, our results point out the good potential of Plasma. In particular, we appreciated an up-regulation in some of the most important genes involved in bio-revitalization, such as elastin and hyaluronic acid.

Hyaluronic acid synthesis is required for zebrafish tail fin regeneration

Using genome-wide transcriptional profiling and whole-mount expression analyses of zebrafish larvae, we have identified hyaluronan synthase 3 (has3) as an upregulated gene during caudal fin regeneration. has3 expression is induced in the wound epithelium within hours after tail amputation, and its onset and maintenance requires fibroblast growth factor, phosphoinositide 3-kinase, and transforming growth factor-ß signaling. Inhibition of hyaluronic acid (HA) synthesis by the small molecule 4-methylumbelliferone (4-MU) impairs tail regeneration in zebrafish larvae by preventing injury-induced cell proliferation. In addition, 4-MU reduces the expression of genes associated with wound epithelium and blastema function. Treatment with glycogen synthase kinase 3 inhibitors rescues 4-MU-induced defects in cell proliferation and tail regeneration, while restoring a subset of wound epithelium and blastema markers. Our findings demonstrate a role for HA biosynthesis in zebrafish tail regeneration and delineate its epistatic relationships with other regenerative processes.

[Construction and characterization of hemolysin S gene mutant strain producing hyaluronic acid]

OBJECTIVE

Streptococcus equi subsp. zooepidemicus (GCS) is mainly used to produce hyaluronic acid (HA) in the industry. GCS secretes the hemolysis toxin (streptolysin S, SLS) that causes hemolysis in the host cells. Therefore, the safety of HA produced by GCS is concerned. We constructed an engineering strain, to produce commercial HA without SLS by knocking out saga.

METHOD

The sagA of GCS was knocked out by the thermosensitive delivery vector system pJR700. The sagA mutant was identified through PCR with primers homologous to the flanking regions and SLS analysis. The yield of HA, HA molecular weight and virulence factors such as streptolysin Hylc, hyaluronate lyase, glyceraldehyde-3-phosphate dehydrogenase and cell surface proteins were determined by spectrophotometer and SDS-PAGE.

RESULT

We constructed successfully the in-frame deletion sagA mutant strain of GCS. In the sagA mutant, HA titer increased more than 30% than that of the wild type strain and no SLS hemolytic activity was detected. Compared to the wild type strain the sagA mutant decreased the quality of surface proteins, hemolytic Hylc activity and glyceraldehyde-3-phosphate dehydrogenase activity. The activities of hyaluronidase and cell were increased in the sagA mutant.

CONCLUSION

The sagA not only expressed hemolysis S but also regulated production of HA, the quality of surface proteins and activities of hyaluronidase, hemolysis Hylc and glyceraldehydes-3-phosphate dehydrogenase in Streptococcus equi subsp. zooepidemicus.

Morphological and Functional Changes of Human Vocal Fold Fibroblasts with Hepatocyte Growth Factor

Fibroblasts produce extracellular matrix and play an important role in wound healing and scarring. Hepatocyte growth factor (HGF) has strong antifibrotic activity, and has been suggested to have therapeutic potential for treatment of fibrotic diseases. In the present in vitro study, morphological and functional changes of human vocal fold fibroblasts with HGF were examined by transmission electron microscopy and enzyme-linked immunosorbent assay to help clarify the potential use of HGF in the prevention or treatment of vocal fold scarring. The HGF stimulated the production of hyaluronic acid (HA) and decreased the production of collagen type I from the fibroblasts in Reinke's space (FbRS), whereas fibronectin production was not affected. The HGF also changed the shape of the FbRS from an oval shape toward a spindle and stellate shape, and developed Golgi apparatus (GA) and rough endoplasmic reticulum (rER) in the FbRS. The fibroblasts in the macula flava (FbMF) presented with much more production of HA and collagen type I than did FbRS, and were more frequently formed in a stellate shape with well-developed GA and rER. The HGF decreased the production of collagen type I from the FbMF, but barely affected the FbMF in terms of the shape of the cells, the development of GA and rER, or the production of HA. These results were interpreted to suggest that the FbMF are not as susceptible to HGF as are FbRS. On the contrary, HGF appeared to activate the FbRS and modify the function. The increased HA and decreased collagen type I production from the FbRS suggest that HGF may be useful in the prevention or treatment of fibrotic vocal fold scarring.

Differential activation of noncanonical SMAD2/SMAD3 signaling by bone morphogenetic proteins causes disproportionate induction of hyaluronan production in immortalized human granulosa cells

Successful fertilization depends upon proper cumulus-oocyte complex (COC) expansion. Synthesized by hyaluronan synthases (HASs), hyaluronan forms the backbone of the COC matrix and plays a critical role in COC expansion. This study investigated the effects and mechanisms of ovarian BMPs on HAS expression and hyaluronan production in human granulosa cells. Treatment with BMP4, BMP6, BMP7 or BMP15 induced differing levels of noncanonical SMAD2/3, but equal levels of canonical SMAD1/5/8, phosphorylation which were mirrored by differing levels of HAS2 up-regulation and hyaluronan production. The effects of BMP4 and BMP15 on HAS2 mRNA were partially reversed by knockdown of SMAD3, and blocked by knockdown of SMAD2+SMAD3 or SMAD4. BMP4-induced SMAD2/3 phosphorylation and HAS2 mRNA up-regulation were mediated by both BMP and activin/transforming growth factor-β type I receptors. Our results suggest differential activation of noncanonical SMAD2/SMAD3 signaling by BMPs causes disproportionate induction of HAS2 expression and hyaluronan production in immortalized human granulosa cells.

Cell density-dependent stimulation of PAI-1 and hyaluronan synthesis by TGF-β in orbital fibroblasts

During the course of Graves' orbitopathy (GO), orbital fibroblasts are exposed to factors that lead to proliferation and extracellular matrix (ECM) overproduction. Increased levels of tissue plasminogen activator inhibitor type 1 (PAI-1 (SERPINE1)) might promote the accumulation of ECM components. PAI-1 expression is regulated by cell density and various cytokines and growth factors including transforming growth factorβ(TGF-β). We examined the effects of increasing cell densities and TGF-β on orbital fibroblasts obtained from GO patients and controls. Responses were evaluated by the measurement of proliferation, PAI-1 expression, and ECM production. There was an inverse correlation between cell density and the per cell production of PAI-1. GO orbital, normal orbital, and dermal fibroblasts behaved similarly in this respect. Proliferation rate also declined with increasing cell densities. Hyaluronan (HA) production was constant throughout the cell densities tested in all cell lines. In both GO and normal orbital fibroblasts, but not in dermal fibroblasts, TGF-β stimulated PAI-1 production in a cell density-dependent manner, reaching up to a five-fold increase above baseline. This has been accompanied by increased HA secretion and pericellular HA levels at high cell densities. Increasing cell density is a negative regulator of proliferation and PAI-1 secretion both in normal and GO orbital fibroblasts; these negative regulatory effects are partially reversed in the presence of TGF-β. Cell density-dependent regulation of PAI-1 expression in the orbit, together with the local cytokine environment, may have a regulatory role in the turnover of the orbital ECM and may contribute to the expansion of orbital soft tissue in GO.

Pathological Roles of Interleukin-22 in the Development of Recurrent Hepatitis C after Liver Transplantation

OBJECTIVE

The aim of this study was to longitudinally evaluate and analyze the role of interleukin-22-producing CD4 positive cells (IL-22) in the pathogenesis of Hepatitis C Virus recurrence after Orthotopic Liver Transplantation (HCV-OLT).

METHODS

15 HCV-OLT, 15 age- and gender- matched non-HCV post-OLT (OLT) and 15 hepatitis C virus infected (HCV) patients were enrolled into our study from the liver transplantation and research center at Beijing 302 Hospital. We determined the frequencies of IL-22 using flow cytometry and expression of IL-22 mRNA using PCR in peripheral blood and liver tissue. We also divided HCV-OLT patients into rapid fibrosis progression (RFP) and slow fibrosis progression (SFP), examined IL-22 cells and analyzed the correlations between IL-22 frequencies and liver injury, fibrosis and clinical parameters. Moreover, we investigated the role of IL-22 in Human Hepatic Stellate Cells (HSCs).

RESULTS

The levels of serum IL-22, frequencies of IL-22 producing cells in peripheral blood mononuclear cells, and expression of IL-22 mRNA and protein in the liver in the HCV-OLT group were significantly higher than that in the HCV and OLT groups. Furthermore, eight (53.3%) patients developed RFP after two years; another three patients were diagnosed liver cirrhosis. The frequencies of IL-22 were much higher in RFP compared with SFP, while no significant difference existed between OLT and SFP. Intrahepatic IL-22 positive cells were located in fibrotic areas and significantly correlated with α-smooth muscle actin (α-SMA) and fibrosis staging scores, not with grading scores and HCRVNA. In vitro, IL-22 administration prevented HSCs apoptosis, promoted HSCs proliferation and activation, up-regulated the expression of HSC-sourced growth factors including α-SMA, TGF-β and TIMP-1, and increased the production of liver fibrosis markers including laminin, hyaluronic acid and collagen type IV.

CONCLUSION

Peripheral and intrahepatic IL-22 is up-regulated and plays a pathological role in exacerbating liver fibrosis by activating HSCs in HCV-OLT patients, which may predict RFP and serve as an attractive target for anti-fibrotic therapy.

Treatment with the hyaluronic Acid synthesis inhibitor 4-methylumbelliferone suppresses LPS-induced lung inflammation

Exposure to bacterial endotoxins, such as lipopolysaccharide (LPS), can lead to the induction of acute lung injury/acute respiratory distress syndrome (ALI/ARDS). To date, there are no known effective treatments for LPS-induced inflammation. In the current study, we investigated the potential use of the hyaluronic acid (HA) synthesis inhibitor 4-methylumbelliferone (4-MU) on LPS-induced acute lung inflammation. Culturing LPS-activated immune cells with 4-MU led to reduced proliferation, reduced cytokine production, and an increase in apoptosis when compared to untreated cells. Treatment of mice with 4-MU led to protection from LPS-induced lung injury. Specifically, 4-MU treatment led to a reduction in LPS-induced hyaluronic acid synthase (HAS) messenger RNA (mRNA) levels, reduction in lung permeability, and reduction in proinflammatory cytokine production. Taken together, these results suggest that use of 4-MU to target HA production may be an effective treatment for the inflammatory response following exposure to LPS.

Hyaluronan synthase 2 overexpression is correlated with the tumorigenesis and metastasis of human breast cancer

Extracellular matrix (ECM) is closely correlated with the malignant behavior of breast cancer cells. Hyaluronan (HA) is one of the main components of ECM, and actively regulates cell adhesion, migration and proliferation by interacting with specific cell surface receptors such as CD44 and RHAMM. HA synthase 2 (HAS2) catalyzes the synthesis of HA, but its role in breast tumorigenesis remains unclear. This study assessed the roles of HAS2 in malignant behavior of human breast cancer and sought to provide mechanistic insights into the biological and pivotal roles of HAS2. We observed HAS2 was overexpressed in breast cancer cell lines and invasive duct cancer tissues, compared with the nonmalignant breast cell lines and normal breast tissues. In addition, a high level of HAS2 expression was statistically correlated with lymph node metastasis. Functional assays showed that knockdown of HAS2 expression inhibited breast tumor cell proliferation in vivo and in vitro, through the induction of apoptosis or cell cycle arrest. Further studies showed that the HA were elevated in breast cancer, and HAS2 could upregulate HA expression. In conclusion, HAS2-HA system influences the biological characteristics of human breast cancer cells, and HAS2 may be a potential prognostic marker and therapeutic target in breast cancer.

Hyaluronan cable formation by ocular trabecular meshwork cells

Hyaluronan (HA) in the ocular trabecular meshwork (TM) is a critical modulator of aqueous humor outflow. Individual HA strands in the pericellular matrix can coalesce to form cable-like structures, which have different functional properties. Here, we investigated HA structural configuration by TM cells in response to various stimuli known to stimulate extracellular matrix (ECM) remodeling. In addition, the effects of HA cable induction on aqueous outflow resistance was determined. Primary TM cell cultures grown on tissue culture-treated plastic were treated for 12-48 h with TNFα, IL-1α, or TGFβ2. TM cells grown on silicone membranes were subject to mechanical stretch, which induces synthesis and activation of ECM proteolytic enzymes. HA structural configuration was investigated by HA binding protein (HAbp) staining and confocal microscopy. HAbp-labeled cables were induced by TNFα, TGFβ2 and mechanical stretch, but not by IL-1α. HA synthase (HAS) gene expression was quantitated by quantitative RT-PCR and HA concentration was measured by ELISA assay. By quantitative RT-PCR, HAS-1, -2, and -3 genes were differentially up-regulated and showed temporal differences in response to each treatment. HA concentration was increased in the media by TNFα, TGFβ2 and IL-1α, but mechanical stretch decreased pericellular HA concentrations. Immunofluorescence and Western immunoblotting were used to investigate the distribution and protein levels of the HA-binding proteins, tumor necrosis factor-stimulated gene-6 (TSG-6) and inter-α-inhibitor (IαI). Western immunoblotting showed that TSG-6 and IαI were increased by TNFα, TGFβ2 and IL-1α, but mechanical stretch reduced their levels. The underlying substrate appears to affect the identity of IαI·TSG-6·HA complexes since different complexes were detected when TM cells were grown on a silicone substrate compared to a rigid plastic surface. Porcine anterior segments were perfused with 10 μg/ml polyinosinic:polycytidylic acid (polyI:C), a potent inducer of HA cables, and outflow rates were monitored for 72 h. PolyI:C had no significant effect on outflow resistance in porcine anterior segments perfused at physiological pressure. Collectively, HAS gene expression, HA concentration and configuration are differentially modified in response to several treatments that induce ECM remodeling in TM cells. In ocular TM cells, our data suggests that the most important determinant of HA cable formation appears to be the ratio of HA chains produced by the different HAS genes. However, the act of rearranging pericellular HA into cable-like structures does not appear to influence aqueous outflow resistance.

Regulation of hyaluronan synthesis in vascular diseases and diabetes

Cell microenvironment has a critical role determining cell fate and modulating cell responses to injuries. Hyaluronan (HA) is a ubiquitous extracellular matrix glycosaminoglycan that can be considered a signaling molecule. In fact, interacting with several cell surface receptors can deeply shape cell behavior. In vascular biology, HA triggers smooth muscle cells (SMCs) dedifferentiation which contributes to vessel wall thickening. Furthermore, HA is able to modulate inflammation by altering the adhesive properties of endothelial cells. In hyperglycemic conditions, HA accumulates in vessels and can contribute to the diabetic complications at micro- and macrovasculature. Due to the pivotal role in favoring atherogenesis and neointima formation after injuries, HA could be a new target for cardiovascular pathologies. This review will focus on the recent findings regarding the regulation of HA synthesis in human vascular SMCs. In particular, the effects of the intracellular HA substrates availability, adenosine monophosphate-activated protein kinase (AMPK), and protein O-GlcNAcylation on the main HA synthetic enzyme (i.e., HAS2) will be discussed.

Hyaluronan up-regulation is linked to renal dysfunction and hearing loss induced by silver nanoparticles

Increased application of silver nanoparticles (AgNPs) has raised concerns on their potential adverse effects on human health. However, the precise toxicological mechanisms are not known in detail. The current study hypothesized that AgNPs induced glycosaminoglycan accumulation in the basement membrane that associated with the up-regulation of its component hyaluronic acid, known as a hydrophilic molecule of binding and retaining water, and caused toxicities in the kidney and cochlea. Rats administered AgNPs through either intravenous or intratympanic injection were observed at different time points after exposure. The concentrations of creatinine and urea in the serum were elevated remarkably, and proteins leaked into the urine were increased. A significant hearing loss over a broad range of frequencies was indicated. AgNP exposure induced glycosaminoglycan accumulation and hyaluronic acid up-regulation in the basement membrane. Abundant apoptotic cell death was demonstrated in the AgNP-exposed organs. Our results suggested that glycosaminoglycan accumulation associated with the up-regulation of hyaluronic acid was involved in the toxicities of kidney and cochlea caused by AgNPs.

In vitro model of hyaluronan synthase gene expression associated with lipopolysaccharide-induced inflammation in SW982 cell line

The present study aimed to demonstrate the phenomena of hyaluronan synthesis in response to lipopolysaccharide-induced inflammation in SW982, a human synovial sarcoma cell line. The expression of IL-1ß, including Toll-like receptor 4 and IL-1ß-converting enzyme, was proved to be induced by a reverse transcription-polymerase chain reaction. The expression of HAS genes encoding enzyme hyaluronan synthase 2 and 3, including CD44 gene which encodes the cell surface receptor of hyaluronan were upregulated in association with the activation of inflammation, along with an increase in hyaluronan level in the culture medium. The highest expression of HAS2 and HAS3 was found at 9 h after treatment with lipopolysaccharide. However, HAS1 gene expression was not detectable neither with the non-treatment nor with the treatment with lipopolysaccharide. Dexamethasone at 30 nM significantly suppressed lipopolysaccharide-induced HAS genes expression, leading to the decline of the hyaluronan level in the culture medium. Our results demonstrated the effective tool for studying hyaluronan synthesis in association with inflammation in the SW982 cell line.

Growth promoting effect of hyaluronan synthesis promoting substances on Japanese eel leptocephali

Hyaluronans (HAs) are glycosaminoglycans produced in the bodies of Anguilliform and Elopiform leptocephali, and play a role in metabolic energy. In mammals, HA synthesis-promoting substances (HASPS) up-regulate the expression of HA synthase (HAS) and increase the amount of HA in the body. In this study, Japanese eel leptocephali were fed a HASPS containing diet. We analyzed HAS1s and HAS2 expression, HA content, and their influence on growth. HASPS extracted from Grifola frondosa promoted HAS1s and HAS2 mRNA and HA content. Other than mammals, these results are first reported in vertebrate. Moreover, HASPS extracted from G. frondosa promoted leptocephalus growth. The relationship between growth and HA in the leptocephali is not yet clear. However, based on our results we hypothesize that HA is involved in the storage of energy, which is metabolized to sugars when needed for metabolic energy.

A novel approach for skin rejuvenation by regenerative medicine: delivery of stem cell-derived growth factors through an iontophoretic system

PURPOSE

It was hypothesized that mesenchymal stem cell (MSC)-derived growth factor applied by iontophoretic transdermal delivery might improve ultraviolet beam (UVB)-induced photoaged skin. This experimental study was performed to confirm this hypothesis.

MATERIALS AND METHODS

Photoaged skin was induced in nude rat after an 8-week regimen of UVB irradiation, and an MSC-conditioned medium (MSC-CM) was conducted by an iontophoretic transdermal transport system. The effect of iontophoresis with MSC-CM was evaluated by replica method and measurement of the hyaluronic acid level in the dermis after treatment.

RESULTS

MSC-CM conducted by iontophoresis significantly reduced all parameters for wrinkles and increased hyaluronic acid in the dermis.

CONCLUSION

MSC-CM application by iontophoresis can be considered as a supplemental treatment to the methods for skin rejuvenation.

Expression of hyaluronan (hyaluronic acid) in the developing laminar architecture of the human fetal brain

Hyaluronan (also called hyaluronic acid or HA) plays a key role in the morphogenesis of the brain, but little is known about its expression in the human fetal neocortex. Using immunohistochemical methods, we assayed the expression of HA, glial fibrillary acidic protein, vimentin, nestin, and proliferating cell nuclear antigen in paraffin-embedded histologic sections of 8 mid-term fetuses (estimated gestational age, 12-16 weeks; crown-rump length, 75-120mm). At 12-13 weeks, HA was expressed strongly along the membranes of many cells in the cortical plate and the layer 1 or marginal zone, but showed weak, spotty expression in a fiber-rich layer adjacent to the cortical plate, called the cortical stratified transitional field-1 (STF-1 or a primitive form of the subplate). At 15-16 weeks, HA was expressed in the layer 1 and in the early subplate or presubplate, but less strongly in cells of the possible STF-5 near the subventricular zone. However, the positive observation in STF-5 was probably a result of individual difference in development. The developing cortical plate seemed to produce HA in the presubplate to harbor axonal plexus of various afferent systems, while Cajal-Retzius cells were likely to accumulate HA in the layer 1. The HA-rich zones, those sandwiched the cortical plate, might avoid further migration of cortical cells.

Hyaluronan synthesis and myogenesis: a requirement for hyaluronan synthesis during myogenic differentiation independent of pericellular matrix formation

Exogenous hyaluronan is known to alter muscle precursor cell proliferation, migration, and differentiation, ultimately inhibiting myogenesis in vitro. The aim of the current study was to investigate the role of endogenous hyaluronan synthesis during myogenesis. In quantitative PCR studies, the genes responsible for synthesizing hyaluronan were found to be differentially regulated during muscle growth, repair, and pathology. Although all Has genes (Has1, Has2, and Has3) were differentially regulated in these models, only Has2 gene expression consistently associated with myogenic differentiation. During myogenic differentiation in vitro, Has2 was the most highly expressed of the synthases and increased after induction of differentiation. To test whether this association between Has2 expression and myogenesis relates to a role for Has2 in myoblast differentiation and fusion, C2C12 myoblasts were depleted of Has2 by siRNA and induced to differentiate. Depletion of Has2 inhibited differentiation and caused a loss of cell-associated hyaluronan and the hyaluronan-dependent pericellular matrix. The inhibition of differentiation caused by loss of hyaluronan was confirmed with the hyaluronan synthesis inhibitor 4-methylumbelliferone. In hyaluronan synthesis-blocked cultures, restoration of the pericellular matrix could be achieved through the addition of exogenous hyaluronan and the proteoglycan versican, but this was not sufficient to restore differentiation to control levels. These data indicate that intrinsic hyaluronan synthesis is necessary for myoblasts to differentiate and form syncytial muscle cells, but the hyaluronan-dependent pericellular matrix is not sufficient to support differentiation alone; additional hyaluronan-dependent cell functions that are yet unknown may be required for myogenic differentiation.

Interleukin-10 regulates the fetal hyaluronan-rich extracellular matrix via a STAT3-dependent mechanism

BACKGROUND

The midgestational fetus is capable of regenerative healing. We have recently demonstrated a novel role for the anti-inflammatory cytokine interleukin 10 (IL-10) as a regulator of hyaluronan (HA) in the extracellular matrix. The signaling pathway of IL-10 has been studied in monocytes but is unknown in dermal fibroblasts. We hypothesized IL-10 signals through its primary receptor, IL-10R1, to activate STAT3, resulting in HA synthesis.

METHODS

Murine midgestational (E14.5) fetal fibroblasts were evaluated in vitro. Pericellular matrix was quantified using a particle exclusion assay. STAT3 levels and cellular localization were evaluated by Western blot/band densitometry and immunocytochemistry/confocal microscopy. HA levels were quantified by enzyme-linked immunosorbent assay. The effects of IL-10R1 signal blockade by a neutralizing antibody and STAT3 inhibition were evaluated. An ex vivo midgestation fetal forearm culture incisional wound model in control and transgenic IL-10-/- mice was used to evaluate the role of STAT3 on the extracellular matrix.

RESULTS

Fetal fibroblasts produce a robust hyaluronan-rich pericellular matrix that is IL-10R1 and STAT3 dependent. Inhibition of IL-10R1 signaling results in decreased phosphorylated STAT3 levels and inhibition of nuclear localization. Inhibition of STAT3 results in decreased HA production. At day 3, midgestation fetal wounds have efficient re-epithelialization, which is significantly slowed in IL-10-/- wounds at the same gestation and with inhibition of STAT3.

CONCLUSIONS

Our data demonstrate that IL-10 regulates HA synthesis through its primary receptor IL-10R1 and STAT3 activation. This supports a novel nonimmunoregulatory mechanism of IL-10 in its role in fetal regenerative wound healing.

Hyaluronan synthesis in cultured tobacco cells (BY-2) expressing a chlorovirus enzyme: cytological studies

Extraction of hyaluronan from animals or microbial fermentation has risks including contamination with pathogens and microbial toxins. In this work, tobacco cultured-cells (BY-2) were successfully transformed with a chloroviral hyaluronan synthase (cvHAS) gene to produce hyaluronan. Cytological studies revealed accumulation of HA on the cells, and also in subcellular fractions (protoplasts, miniplasts, vacuoplasts, and vacuoles). Transgenic BY-2 cells harboring a vSPO-cvHAS construct containing the vacuolar targeting signal of sporamin connected to the N-terminus of cvHAS accumulated significant amounts of HA in vacuoles. These results suggested that cvHAS successfully functions on the vacuolar membrane and synthesizes/transports HA into vacuoles. Efficient synthesis of HA using this system provides a new method for practical production of HA.

[Optimization of Streptococcus equi subsp. zooepidemicus cultivation process--producer of hyaluronic acid]

AIM

Selection of high-mucoid morphotype of Streptococcus equi subsp. zooepidemicus (Streptococcus zooepidemicus) and study of its morphological, physiological, biochemical and technological characteristics for providing increased secretion of hyaluronic acid (HA).

MATERIALS AND METHODS

Submerged cultivation was performed in 100 ml glass flasks without baffles or in 1.5 or 10 1 laboratory bioreactors. LB and MRS media were used for cultivation. Mutagenesis was carried out by UV exposure with consequent selection of mucoid phenotype. HA was determined by carbazole method or after exhaustive acid hydrolysis by reaction of N-acetylglucosamine with Morgan-Elson reagent. Total hyaluronidase activity was evaluated by viscosimeter. Determination of cell and capsule size, ability to ferment carbohydrates and other microbiological, physiological and biochemical tests were performed by standard techniques.

RESULTS

Instability of capsule phenotype of S. zooepidemicus B-8014 strain was revealed that is explained most probably by formation under certain conditions of bacterial hyaluronidase. This is confirmed by a reduction of HA concentration in cultural medium at pre- and stationary growth phases. Mucoid strain S. zooepidemicus KB-04 was obtained by mutagenesis with subsequent selection that is characterized by increased capsules. The strain was studied for HA formation. Optimization of growth medium composition, physical-chemical conditions and modes of cultivation allowed to significantly increase HA yield.

CONCLUSION

The studies of morphologic, physiologic, biochemical and technological characteristics of the high-mucoid S. zooepidemicus KB-04 strain obtained by mutagenesis with consequent selection were performed, conditions of its cultivation and composition of growth mediu by carbon source and content of bivalent metal ions were optimized.

Metabolic engineering of Bacillus subtilis for the efficient biosynthesis of uniform hyaluronic acid with controlled molecular weights

Bacillus subtilis was engineered into an efficient hyaluronic acid (HA) producer by introducing two inducible artificial operons carrying HA synthase gene from Pasteurella multocida and precursor genes encoding enzymes involved in synthesis of the sugar precursors. A two-stage induction strategy was established for metabolic engineering of recombinant B. subtilis to efficiently produce uniform HA with controlled molecular weights. Strain TPG223 produced larger HA molecules (yield=6.8 g/L; molecular weight=4.5 MDa) than strain PG6181 (yield=2.4 g/L; molecular weight=13 KDa), indicating that the enzymes involved in the synthesis of UDP-glucuronic acid are essential for HA biosynthesis. Strain TPG223 was able to synthesize HA molecules ranging in molecular weight from 8 KDa to 5.4 MDa indicating that size control is achievable in vivo through appropriate tools. The work reported here not only advanced mechanisms research of size control in vivo, but also could be an attractive alternative for commercial preparation of uniform size-defined HA.

20S-hydroxyvitamin D3, noncalcemic product of CYP11A1 action on vitamin D3, exhibits potent antifibrogenic activity in vivo

CONTEXT

There is no effective treatment for systemic sclerosis and related fibrosing diseases. Recently the action of CYP11A1 on vitamin D(3) was shown to produce biologically active 20S-hydroxyvitamin D [20(OH)D(3)] and 20,23(OH)(2)D(3), 20,22(OH)(2)D(3), and 17,20,23(OH)(3)D(3).

OBJECTIVES

Because 20(OH)D(3) is noncalcemic (nontoxic) in vivo at very high doses, we evaluated its antifibrogenic activities both in vitro and in vivo. Because it is further metabolized by CYP11A1, we also tested preclinical utilities of its hydroxyderivatives, especially 20,23(OH)(2)D(3).

DESIGN

Human dermal fibroblasts from scleroderma and normal donors were used to test the efficiency of hydroxyvitamin D derivatives in inhibiting TGF-β1-induced collagen and hyaluronan synthesis and inhibiting cell proliferation. The in vivo activity of 20(OH)D(3) was tested using bleomycin-induced sclerosis in C57BL/6 mice.

RESULTS

20(OH)D(3) and 20,23(OH)(2)D(3) inhibited TGF-β1-induced collagen and hyaluronan synthesis similarly to 1,25(OH)(2)D(3) in cultured human fibroblasts. Also, 20(OH)D(3), 20,23(OH)(2)D(3), and 1,25(OH)(2)D(3) suppressed TGF-β1-induced expression of COL1A2, COL3A1, and hyaluronan synthase-2 mRNA, indicating that they regulate these matrix components at the transcriptional level. 20(OH)D(3), 20,23(OH)(2)D(3), 20,22(OH)(2)D(3), and 17,20,23(OH)(3)D(3) inhibited proliferation of dermal fibroblasts with comparable potency with 1,25(OH)(2)D(3), with 20(OH)D(2) being less active and 1α(OH)D(3) being almost inactive. 20,23(OH)(2)D(3) at 3 μg/kg had no effect on serum Ca(++) or fibroblast growth factor-23 levels and did not cause any noticeable signs of morbidity. 20(OH)D(3) markedly suppressed fibrogenesis in mice given sc bleomycin as demonstrated by total collagen content and hematoxylin and eosin staining of skin biopsies.

CONCLUSIONS

20(OH)D(3) is an excellent candidate for preclinical studies on scleroderma, with other CYP11A1-derived products of its metabolism deserving further testing for antibrogenic activity.

Regulation of wound healing by granulocyte-macrophage colony-stimulating factor after vocal fold injury

Objectives

Vocal fold (VF) scarring remains a therapeutic challenge. Granulocyte-macrophage colony-stimulating factor (GM-CSF) facilitates epithelial wound healing, and recently, growth factor therapy has been applied to promote tissue repair. This study was undertaken to investigate the effect of GM-CSF on VF wound healing in vivo and in vitro.

Methods

VF scarring was induced in New Zealand white rabbits by direct injury. Immediately thereafter, either GM-CSF or PBS was injected into the VFs of rabbits. Endoscopic, histopathological, immunohistochemical, and biomechanical evaluations of VFs were performed at 3 months post-injury. Human vocal fold fibroblasts (hVFFs) were cultured with GM-CSF. Production of type I and III collagen was examined immunocytochemically, and the synthesis of elastin and hyaluronic acids was evaluated by ELISA. The mRNA levels of genes related to ECM components and ECM production-related growth factors, such as HGF and TGF-ß1, were examined by real time RT-PCR.

Results

The GM-CSF-treated VFs showed reduced collagen deposition in comparison to the PBS-injected controls (P<0.05). Immunohistochemical staining revealed lower amounts of type I collagen and fibronectin in the GM-CSF-treated VFs (P<0.05 and P<0.01, respectively). Viscous and elastic shear moduli of VF samples were significantly lower in the GM-CSF group than in the PBS-injected group (P<0.001 and P<0.01, respectively). Mucosal waves in the GM-CSF group showed significant improvement when compared to the PBS group (P = 0.0446). GM-CSF inhibited TGF-β1-induced collagen synthesis by hVFFs (P<0.05) and the production of hyaluronic acids increased at 72 hours post-treatment (P<0.05). The expressions of HAS-2, tropoelastin, MMP-1, HGF, and c-Met mRNA were significantly increased by GM-CSF, although at different time points (P<0.05).

Conclusion

The present study shows that GM-CSF offers therapeutic potential for the remodeling of VF wounds and the promotion of VF regeneration.

Relaxin regulates hyaluronan synthesis and aquaporins in the cervix of late pregnant mice

Cervical ripening is associated with loss of structural integrity and tensile strength, thus enabling the cervix to dilate at term. It is characterized by changes in glycosaminoglycan composition, increased water content, and a progressive reorganization of the collagen network. The peptide hormone relaxin via interaction with its receptor, relaxin family peptide receptor 1 (RXFP1), promotes tissue hydration and increases cervical hyaluronan (HA) concentrations, but the mechanisms that regulate these effects are not known. This study in relaxin mutant (Rln(-/-)) mice tested the hypothesis that relaxin regulates HA synthase and aquaporin (AQP) expression in the cervix. We also assessed expression of the RXFP1 protein by immunohistochemistry. Pregnant Rln(-/-) mice had lower Has2 and Aqp3 expression on d 18.5 of pregnancy and decreased cervical HA compared with wild-type Rln(+/+) mice. Chronic infusion of relaxin for 4 or 6 d in pregnant Rln(-/-) mice reversed these phenotypes and increased Has2 and Aqp3 compared with placebo controls. Relaxin-treated mice also had lower Has1 and Aqp5. Changes in gene expression were paralleled by increases in cervical HA and variations in AQP3 and AQP5 protein localization in epithelial cells of Rln(-/-) cervices. Our findings demonstrate that relaxin alters AQP expression in the cervix and initiates changes in glycosaminoglycan composition through increased HA synthesis. These effects are likely mediated through RXFP1 localized to subepithelial stromal cells and epithelial cells. We suggest these actions of relaxin collectively promote water recruitment into the extracellular matrix to loosen the dense collagen fiber network.

Inhibition of hyaluronan synthesis reduces versican and fibronectin levels in trabecular meshwork cells

Hyaluronan (HA) is a major component of the extracellular matrix (ECM) and is synthesized by three HA synthases (HAS). Similarities between the HAS2 knockout mouse and the hdf mutant mouse, which has a mutation in the versican gene, suggest that HA and versican expression may be linked. In this study, the relationship between HA synthesis and levels of versican, fibronectin and several other ECM components in trabecular meshwork cells from the anterior segment of the eye was investigated. HA synthesis was inhibited using 4-methylumbelliferone (4MU), or reduced by RNAi silencing of each individual HAS gene. Quantitative RT-PCR and immunoblotting demonstrated a reduction in mRNA and protein levels of versican and fibronectin. Hyaluronidase treatment also reduced versican and fibronectin levels. These effects could not be reversed by addition of excess glucose or glucosamine or exogenous HA to the culture medium. CD44, tenascin C and fibrillin-1 mRNA levels were reduced by 4MU treatment, but SPARC and CSPG6 mRNA levels were unaffected. Immunostaining of trabecular meshwork tissue after exposure to 4MU showed an altered localization pattern of HA-binding protein, versican and fibronectin. Reduction of versican by RNAi silencing did not affect HA concentration as assessed by ELISA. Together, these data imply that HA concentration affects synthesis of certain ECM components. Since precise regulation of the trabecular meshwork ECM composition and organization is required to maintain the aqueous humor outflow resistance and intraocular pressure homeostasis in the eye, coordinated coupling of HA levels and several of its ECM binding partners should facilitate this process.

A stimulatory thyrotropin receptor antibody enhances hyaluronic acid synthesis in graves' orbital fibroblasts: inhibition by an IGF-I receptor blocking antibody

CONTEXT

Graves' ophthalmopathy (GO) is characterized by expanded volume of the orbital fat and extraocular muscle tissues and elevated levels of TSH receptor autoantibodies (TRAb). The expansion of orbital tissues involves accumulation of hyaluronic acid (HA) within the orbit.

OBJECTIVE

The objective of the study was to determine whether a monoclonal stimulatory TRAb (M22) impacts HA synthesis in GO orbital cells and, if so, whether this might be blocked by an IGF-I receptor (IGF-IR)-blocking antibody (1H7) or inhibitors of various downstream signaling cascades.

DESIGN

GO orbital fibroblast cultures (n = 6) were treated with M22, bovine TSH (bTSH), or IGF-I in serum-free medium. Some cultures also received 1H7, LY294002, rapamycin, or protein kinase A inhibitor.

MAIN OUTCOME MEASURES

HA production and phosphorylated Akt levels in media or immunoblotting for phosphorylated Akt were measured.

RESULTS

M22 or bTSH stimulated HA synthesis (2.1-fold with 100 ng/ml M22 and 1.9-fold with 10 U/liter bTSH; P < 0.05 each). M22-induced HA synthesis was inhibited by LY294002 or rapamycin but not by protein kinase inhibitor. HA synthesis stimulated by M22 or IGF-I was inhibited by 1H7 (mean 36.6 ± 5.6% and mean 45.8 ± 7.6%, respectively; P < 0.05 each). Similarly, M22- or IGF-I-stimulated Akt phosphorylation was inhibited by 1H7 (mean 54 ± 9.6 and 36.1 ± 8.8%, respectively; P = 0.01 each).

CONCLUSIONS

The stimulatory TRAb M22 increases HA production in undifferentiated GO orbital fibroblasts via phosphoinositide 3-kinase/phosphorylated AKT/mammalian target of rapamycin activation. Blockade of IGF-IR inhibits both HA synthesis and Akt phosphorylation induced by M22 or IGF-I in these cells, suggesting that TSH receptor and IGF-IR signaling may be closely linked in the GO orbit.