HAS2 mRNA Expression Research Articles

Hyaluronic acid inhibition by 4-methylumbelliferone reduces the expression of cancer stem cells markers during hepatocarcinogenesis

Hyaluronic acid (HA) is a glycosaminoglycan of extracellular matrix related to cell surface which interacts with various cell types. To understand the role of HA during hepatocarcinogenesis, we assessed the effect of the inhibition of HA deposition and its association with heterogeneous hepatocellular carcinoma (HCC) cells. In this study, we used transgenic mice C57BL/6J-Tg(Alb1HBV)44Bri/J (HBV-TG) and normal C57BL/6 J (WT) for in vivo study, while HCC cells Huh7 and JHH6 as in vitro models. Both models were treated with an HA inhibitor 4-methylumbelliferone (4MU). We observed that 4MU treatments in animal model down-regulated the mRNA expressions of HA-related genes Has3 and Hyal2 only in HBV-TG but not in normal WT. As observed in vivo, in HCC cell lines, the HAS2 mRNA expression was down-regulated in Huh7 while HAS3 in JHH6, both with or without the presence of extrinsic HA. Interestingly, in both models, the expressions of various cancer stem cells (CD44, CD90, CD133, and EpCAM) were also decreased. Further, histological analysis showed that 4MU treatment with dose 25 mg/kg/day reduced fibrosis, inflammation, and steatosis in vivo, in addition to be pro-apoptotic. We concluded that the inhibition of HA reduced the expressions of HA-related genes and stem cells markers in both models, indicating a possible modulation of cells-to-cells and cells-to-matrix interaction.

Increased Hyaluronan and TSG-6 in Association with Neuropathologic Changes of Alzheimer's Disease.

Little is known about the extracellular matrix (ECM) during progression of AD pathology. Brain ECM is abundant in hyaluronan (HA), a non-sulfated glycosaminoglycan synthesized by HA synthases (HAS) 1-3 in a high molecular weight (MW) form that is degraded into lower MW fragments. We hypothesized that pathologic severity of AD is associated with increases in HA and HA-associated ECM molecules. To test this hypothesis, we assessed HA accumulation and size; HA synthases (HAS) 1-3; and the HA-stabilizing hyaladherin, TSG-6 in parietal cortex samples from autopsied research subjects with not AD (CERAD = 0, Braak = 0- II, n = 12-21), intermediate AD (CERAD = 2, Braak = III-IV, n = 13-18), and high AD (CERAD = 3, Braak = V-VI, n = 32-40) neuropathologic change. By histochemistry, HA was associated with deposits of amyloid and tau, and was also found diffusely in brain parenchyma, with overall HA quantity (measured by ELSA) significantly greater in brains with high AD neuropathology. Mean HA MW was similar among the samples. HAS2 and TSG-6 mRNA expression, and TSG-6 protein levels were significantly increased in high AD and both molecules were present in vasculature, NeuN-positive neurons, and Iba1-positive microglia. These results did not change when accounting for gender, advanced age (≥ 90 years versus <90 years), or the clinical diagnosis of dementia. Collectively, our results indicate a positive correlation between HA accumulation and AD neuropathology, and suggest a possible role for HA synthesis and metabolism in AD progression.

Expression of hyaluronan synthases upregulated by thyroid hormone is involved in intestinal stem cell development during Xenopus laevis metamorphosis.

During amphibian intestinal remodeling, thyroid hormone (TH) induces adult stem cells, which newly generate the absorptive epithelium analogous to the mammalian one. We have previously shown that hyaluronan (HA) is newly synthesized and plays an essential role in the development of the stem cells via its major receptor CD44 in the Xenopus laevis intestine. We here focused on HA synthase (HAS) and examined how the expression of HAS family genes is regulated during natural and TH-induced metamorphosis. Our quantitative RT-PCR analysis indicated that the mRNA expression of HAS2 and HAS3, but not that of HAS1 and HAS-rs, a unique Xenopus HAS-related sequence, is upregulated concomitantly with the development of adult epithelial primordia consisting of the stem/progenitor cells during the metamorphic climax. In addition, our in situ hybridization analysis indicated that the HAS3 mRNA is specifically expressed in the adult epithelial primordia, whereas HAS2 mRNA is expressed in both the adult epithelial primordia and nearby connective tissue cells during this period. Furthermore, by treating X. laevis tadpoles with 4-methylumbelliferone, a HA synthesis inhibitor, we have experimentally shown that inhibition of HA synthesis leads to suppression of TH-upregulated expression of leucine-rich repeat-containing G protein-coupled 5 (LGR5), an intestinal stem cell marker, CD44, HAS2, HAS3, and gelatinase A in vivo. These findings suggest that HA newly synthesized by HAS2 and/or HAS3 is required for intestinal stem cell development through a positive feedback loop and is involved in the formation of the stem cell niche during metamorphosis.

Clinical significance of hyaluronan levels and its pro-osteogenic effect on mesenchymal stromal cells in myelodysplastic syndromes

BackgroundHyaluronan (HA), a major component of the extracellular matrix, has been proven to play a crucial role in tumor progression. However, it remains unknown whether HA exerts any effects in myelodysplastic syndromes (MDS).MethodsA total of 82 patients with MDS and 28 healthy donors were investigated in this study. We firstly examined the bone marrow (BM) serum levels of HA in MDS by radioimmunoassay. Then we determined HA production and hyaluronan synthase (HAS) gene expression in BM mesenchymal stromal cells (MSC) and mononuclear cells derived from MDS patients. Finally, we investigated the effects of HA on osteogenic differentiation of MSC.ResultsThe BM serum levels of HA was increased in higher-risk MDS patients compared to normal controls. Meanwhile, patients with high BM serum HA levels had significantly shorter median survival than those with low HA levels. Moreover, the HA levels secreted by MSC was elevated in MDS, especially in higher-risk MDS. In addition, HAS-2 mRNA expression was also up-regulated in higher-risk MDS-MSC. Furthermore, we found that MSC derived from MDS patients with high BM serum HA levels had better osteogenic differentiation potential. Moreover, MSC cultured in HA-coated surface presented enhanced osteogenic differentiation ability.ConclusionsOur results show that elevated levels of BM serum HA are related to adverse clinical outcome in MDS. Better osteogenic differentiation of MSC induced by HA may be implicated in the pathogenesis of MDS.

Changes in Hepatic Expression of Hyaluronan Synthases (HAS2 and HAS3) After Treatment with Steptozotocin in Channel Catfish

Streptozotocin (STZ) is commonly used experimentally to induce hyperglycemia in rodents. As an alternative model organism for investigating human obesity, channel catfish show a genetic predisposition toward an accelerated growth rate resulting in a phenotype similar to obese humans. In our previous studies, STZ treatment resulted in hypoglycemia and abnormal liver morphology in channel catfish, indicating that STZ treatment possibly induces liver damage. The mechanisms involved in the STZ‐induced hypoglycemic and tissue damage have never been examined. Another noted marker for liver damage stems from hyaluronan synthases (HAS), which have been associated with tissue damage in both humans and rodents. We hypothesized the expression of HAS mRNA would change in response to liver damage induced by STZ in channel catfish. Juvenile channel catfish were treated with 0, 3.6, 36, 180, or 360 mg STZ/kg body weight (n=4 fish/treatment) on day 0. Liver samples were collected on day 7. Hepatic expression of HAS2 and HAS3 mRNA was examined, using real‐time PCR. Expression of HAS2 and HAS3 mRNA decreased in response to an increased dose of STZ (p &lt; 0.05 and p &lt; 0.10, respectively). These results suggest STZ induces severe liver damage that down regulates the expression of HAS2 and HAS3 mRNA. However, the effects of STZ on gene expression appear to be global, and the tissue damage induced by STZ is not reversible by changes in the amount or activity of HAS.Support or Funding InformationThis research was funded by the APS and a grant from the National Science Foundation Integrative Organismal Systems (IOS) (Grant #IOS‐1238831). It was also supported by an Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health under grant number P20 GM103418.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Stromal-derived factor 1 directly promotes genes expressed within the ovulatory cascade in feline cumulus oocyte complexes.

We hypothesized that the chemokine SDF1/CXCR4 system was present in feline cumulus-oocyte complexes (COCs) and that COCs cultured with SDF1 would directly upregulate gene expression in the ovulatory cascade. Ovaries (n = 50) were obtained from adult domestic cats during the breeding season and COCs were recovered from antral follicles. Because IVM media triggers cumulus-oocyte expansion, culture conditions needed to be optimized to study periovulatory genes. After optimization, the effects of 25ng/ml SDF1 and the CXCR4 inhibitor were examined in a COC culture for 3, 12, and 24h. MEM-hepes with 1% of charcoal stripped-FBS was the optimized culture medium, assessed by the expansion of COCs at 24h in the gonadotropin (GNT) group but not in the media with serum alone. The mRNA expression of HAS2, TNFAIP6, PTX3, and AREG peaked at 3h in GNT group as compared to all other groups (p < 0.05). COCs cultured with SDF1 showed increased HAS2 and TNFAIP6 mRNA expression at 3h compared to negative controls and to the CXCR4 inhibitor group. CXCR4 and SDF1 immunostaining was present in both cumulus cells and the oocyte. These results demonstrate that GNT stimulation upregulates key periovulatory genes and expansion in feline COCs from antral follicles, and support the use of this culture system to examine molecular processes within the COC. In addition, SDF1 directly promotes key periovulatory genes in feline COCs, suggesting that the SDF1-CXCR4 pathway may extend its function beyond a chemoattractant, and may play a direct role within the COC.

4-Methylumbelliferone inhibits enhanced hyaluronan synthesis and cell migration in pancreatic cancer cells in response to tumor-stromal interactions.

Hyaluronic acid (HA) in tumor stroma promotes tumor invasion and progression. 4-Methylumbelliferone (4-MU) is a potent HA synthesis inhibitor. In the present study, the effects of 4-MU on enhanced HA synthesis and cell migration in pancreatic ductal adenocarcinoma (PDAC) cells, in response to co-culture with stromal fibroblasts, was investigated. The HA concentration was determined using ELISA and a Transwell migration assay was used to analyze cell migratory capability. The mRNA expression levels of hyaluronan synthases (HAS1, HAS2 and HAS3) were determined using the quantitative polymerase chain reaction. Co-culture between Panc-1 cells and stromal fibroblasts markedly increased cell migration in association with increasing HA production, which was markedly associated with an increase in HAS3 mRNA expression. Treatment with 4-MU markedly decreased the HA production and cell migration of Panc-1 cells in the co-culture system. The results of the present study suggested that interactions between PDAC cells and stromal fibroblasts increased HA production, resulting in a marked increase in migration of PDAC cells, and 4-MU may be used as a chemotherapeutic agent to inhibit the enhanced migration of PDAC cells in response to tumor-stromal interactions.

Expression Pattern of Hyaluronan Synthase2 in Inflammatory Breast Cancer Cells

Breast cancer (BC) Is the most widely recognized threatening malignant disease around the whole world. It Is the second most incessant reason for malignant tumor growth related to death among woman at different ages. Inflammatory Breast Cancer (IBC) Is the most lethal form of BC with low survival rate. Because of lacking molecular markers, identification of new unique markers for IBC Is warranted. Hyaluronic acid synthases (HASs), particularly HAS2, have shown a critical role in the metastasis of non-inflammatory breast cancer (non-IBC). In this study, we assessed HAS2 mRNA expression by qPCR in the human triple negative non-IBC MDA-MB-231 and IBC SUM-149 cell lines. Our data demonstrated that HAS2 mRNA expression was significantly upregulated in IBC vs. non-IBC breast cancer cell lines. In conclusion, the high expression of HAS2 may represents a marker for IBC and could have a role in IBC pathogenesis.

Age-related changes in cyclic phosphatidic acid-induced hyaluronic acid synthesis in human fibroblasts.

Hyaluronic acid is a major component of the extracellular matrix, which is important for skin hydration. As aging brings skin dehydration, we aimed to clarify the mRNA expression of hyaluronic acid-related proteins in human skin fibroblasts from donors of various ages (range 0.7-69years). Previously, we reported that cyclic phosphatidic acid (cPA), a unique phospholipid mediator, stimulated the expression of HAS2 and increased hyaluronic acid synthesis in human skin fibroblasts (donor age: 3days). In this study, we measured the mRNA expression of hyaluronic acid-related proteins: hyaluronan synthase (HAS) 1-3, hyaluronidase-1, -2, and hyaluronic acid-binding protein (versican). In addition, we tested whether cPA could increase hyaluronic acid synthesis in skin fibroblasts derived from donors of various ages. The expression of HAS1, 3, hyaluronidase-1, and -2 did not change with aging. However, the mRNA expression of versican decreased with aging. Although it is thought that the amount of hyaluronic acid in the dermis decreases with aging, the mRNA expression of HAS2 was increased. But the amount of hyaluronic acid secreted by fibroblasts did not increase with aging. This suggests that the activity and/or protein expression of HAS2 decrease with aging. Furthermore, we observed that cPA caused the increase of hyaluronic acid synthesis at any age, and this effect was increased with aging. These results suggest that aging made the fibroblasts more sensitive to cPA treatment. Therefore, cPA represents a suitable candidate for the health maintenance and improvement of the skin by increasing the level of hyaluronic acid in the dermis.

Leptin supplementation in vitro improved developmental competence of buffalo oocytes and embryos

The aim of the present study was to determine potential role of leptin on in vitro developmental competence of buffalo oocytes and embryos. Slaughterhouse derived culture grade buffalo cumulus oocyte complexes (COCs) were matured in vitro (IVM) with leptin (10 ng/ml) or without leptin (control). In each experiment, a pool of matured COCs was used for further in vitro embryo production and another pool of COCs was used for cumulus cells and mature oocytes isolation to study the relative mRNA expression of developmentally important genes. Presumptive zygotes were cultured in embryo culture (IVC) media supplemented with leptin (10 ng/ml) or without leptin (control). Cleavage rate was higher (p < 0.05) when leptin was supplemented during IVM + IVC, both, as compared to other groups. Higher cleavage rate was observed in leptin-treated groups, though it was non-significant. Blastocyst rate was higher (p < 0.05) in all the leptin treated groups. The relative mRNA expression of LEPR (Ob-Rb), HAS2 and EGFR was significantly (p < 0.05) up-regulated and the expression of CASPASE3 was down-regulated in cumulus cells of leptin-treated groups. The expression of GDF9, BMP15, GLUT1, LEPR and CASPASE3 transcripts in leptin and non-treated oocytes did not differ. The relative mRNA expression of POU5F1and LEPR transcripts in blastocysts was higher (p < 0.05) in leptin-treated groups; the change in expression of GLUT1, INF-τ and CASPASE3 transcripts was not significant (p > 0.05). Thus, it is concluded that leptin promotes developmental competence of bubaline oocytes by modulating cumulus enabling factors and genes regulating pluripotentcy in the blastocysts.

Effects of exosome-like vesicles on cumulus expansion in pigs in vitro.

Cell-secreted vesicles, such as exosomes, have recently been recognized as mediators of cell communication. A recent study in cattle showed the involvement of exosome-like vesicles in the control of cumulus expansion, a prerequisite process for normal ovulation; however, whether this is the case in other mammalian species is not known. Therefore, this study aimed to examine the presence of exosome-like vesicles in ovarian follicles and their effects on cumulus expansion in vitro in pigs. The presence of exosome-like vesicles in porcine follicular fluid (pFF) was confirmed by transmission electron microscopic observation, the detection of marker proteins, and RNA profiles specific to exosomes. Fluorescently labeled exosome-like vesicles isolated from pFF were incorporated into both cumulus and mural granulosa cells in vitro. Exosome-like vesicles were not capable of inducing cumulus expansion to a degree comparable to that induced by follicle-stimulating hormone (FSH). Moreover, exosome-like vesicles had no significant effects on the expression levels of transcripts required for the normal expansion process (HAS2, TNFAIP6, and PTGS2). Interestingly, FSH-induced expression of HAS2 and TNFAIP6 mRNA, but not of PTGS2 mRNA, was significantly increased by the presence of exosome-like vesicles; however, the degree of FSH-induced expansion was not affected. In addition, porcine exosome-like vesicles had no significant effects on the expansion of mouse cumulus-oocyte complexes. Collectively, the present results suggest that exosome-like vesicles are present in pFF, but they are not efficient in inducing cumulus expansion in pigs.

170 SUPPLEMENT OF GROWTH DIFFERENTIATION FACTOR 8 ON PORCINE OOCYTE DURING IN VITRO MATURATION ACTIVATES SMAD2 AND cAMP RESPONSIVE ELEMENT BINDING PROTEIN SIGNALING

Growth differentiation factor 8 (GDF8) is a member of the transforming growth factor-β family that has been identified as a strong physiological regulator. The purpose of this study is to investigate the effects of GDF8 on porcine oocytes during in vitro maturation (IVM). We investigated reactive oxygen species (ROS) levels, specific gene transcription levels in oocytes and cumulus cells (CC) after IVM, and specific protein expression and activation levels in matured CC by Western blotting. Each concentration (0, 1, 10, and 100 ng mL−1) of GDF8 was added in maturation medium (TCM199) during process of IVM. Data were analysed by ANOVA followed by Duncan using SPSS (IBM Corp., Armonk, NY). Data are presented as the mean (replicate numbers) and differences were considered significant at P &lt; 0.05. After 44 h of IVM, oocytes are mechanically denuded from CC with 0.1% hyaluronidase and only metaphase II stage oocytes are counted as nuclear matured oocytes. Each group of matured oocytes are stained by 2′,7′-dichlorodihydrofluorescein diacetate and the fluorescence was captured as graphic files under an epifluorescence microscope. The fluorescence intensities of oocytes were measured using Image J software (National Institutes for Health, Bethesda, MD). The groups treated with 10 and 100 ng mL−1 of GDF8 showed significantly more than 10% decrease in intracellular ROS levels compared with other groups (5 times). To assess the effect of GDF8 on specific gene transcription level changes as a dose response during IVM, real-time PCR was performed. In matured oocytes, the developmental competence marker POU5F1, antioxidant enzymes regulator NRF2, and antiapoptosis gene BCL-2 mRNA transcription levels were significantly increased in the 10 ng mL−1 treatment group compared with control (4 times). In CC, the 10 ng mL−1 treatment groups showed significantly higher PCNA and NRF2 mRNA levels, and the 1 and 10 ng mL−1 treatment groups observed significantly increased cumulus expansion-related genes HAS2, PTX3, and TNFAIP6 mRNA expression levels after IVM (4 times). To determine effect of GDF8 treatment during IVM, GDF8 downstream effector and oocyte ovulation-related protein expression and activation levels were analysed in CC after IVM by Western blotting. The 1 and 10 ng mL−1 treatment groups showed significantly increased phosphorylated (P)-SMAD2 (1.25 and 1.23 times increased compared with the control) and cyclic adenosine monophosphate responsive element binding protein (CREB; 1.31 and 1.32 times increased compared with the control) activation levels (4 times). In conclusion, supplementation of 10 ng mL−1 of GDF8 during IVM effectively increased the oocytes cytoplasmic maturation by reducing of intracellular ROS, and it seems correlated with significantly increased P-SMAD2, which is possibly related with induction of the cumulus cell expansion related genes expression and P-CREB while process of IVM. This work was supported by a grant from the Cooperative Research Program for Agriculture Science &amp; Technology Development (Project No. PJ011288), Rural Development Administration, Republic of Korea.

172 THE APOPTOTIC EFFECTS OF BISPHENOL A-INDUCED MITOCHONDRIAL-DERIVED REACTIVE OXYGEN SPECIES ON MATURATION OF PORCINE OOCYTES IN VITRO

Bisphenol A (BPA) is well known as oestrogen-like chemical and it is widely used in plastic products. Many studies have reported that BPA exposure has a well-known toxicity effect on reproduction function, such as reducing the number of ovulated oocytes, oocyte quality, and maturation rate. Recently, BPA induced mitochondrial-derived reactive oxygen species (mito-ROS) and disrupted mitochondrial homeostasis by increasing of superoxide anions production. In this study, we investigated how the regulation of mito-ROS production may play a critical role in meiotic maturation and expansion of cumulus cells during the in vitro maturation progression of porcine oocytes. Furthermore, we investigated the toxicity effect of BPA exposure on mitochondrial functions and mito-ROS production during porcine oocyte maturation in vitro. All results were analysed using a 1-way ANOVA followed by Bonferroni’s and Tukey’s Multiple Comparison Test and t-tests. First, porcine oocytes were matured in NCSU-23 medium supplemented with BPA (50, 75, and 100 µM) for 44 h. Our results indicated that the rates of matured oocytes were significantly decreased by BPA exposure in a dose-dependent manner (69.4 ± 5.1, 50.9 ± 6.3, and 29.9 ± 5.8% for BPA treatments of 50, 75, and 100 μM) compared with control group (70.2 ± 7.8%; P &lt; 0.05). Next, we confirmed the secretion functions of oocyte and cumulus cell of cumulus-oocyte complex (COC) and ROS production. Cumulus cell secretion factors (has2, tnfaip6, and cx37) mRNA expression in COC were decreased in the BPA-treated (75 µM) group. In addition, mRNA expressions of mitochondrial-specific antioxidant enzymes (sod2, P &lt; 0.001; prdx3, P &lt; 0.01; prdx5, P &lt; 0.001) and mitochondrial apoptosis genes (bax and caspase-3, P &lt; 0.01) were significantly increased in COC of the BPA-treated (75 µM) group. We measured mitochondrial membrane potential and mito-ROS production using JC-1 analysis and Mito-SOX staining, respectively. The BPA treatment caused a rapid decrease of mitochondrial membrane potential maintenance and increase of mito-ROS production in porcine COC. Moreover, mitochondrial-specific ROS scavenger, Mito-Tempo (0.1 µM) treatment was significantly increased the meiotic maturation of porcine oocytes compared with control group (78.5 ± 3.5 v. 65.8 ± 5.0%; P &lt; 0.05). Based on these results, we first confirmed that BPA exposure reduces the meiotic maturation and cumulus cells expansion of COC by increasing mito-ROS production during porcine oocyte maturation in vitro. Therefore, controlling of mito-ROS for mitochondrial function maintenance and apoptosis plays a critical role in improving porcine oocyte maturation in vitro. This work was supported by grants from the Next-Generation BioGreen 21 Program (PJ01117604) and the Bio-industry Technology Development Program (316037–04–1-HD020) through the Rural Development Administration, the Ministry of Agriculture, Food and Rural Affairs, Republic of Korea.

Hyaluronan stimulates pancreatic cancer cell motility

Hyaluronan (HA) accumulates in pancreatic ductal adenocarcinoma (PDAC), but functional significance of HA in the aggressive phenotype remains unknown. We used different models to investigate the effect of HA on PDAC cell motility by wound healing and transwell migration assay. Changes in cell motility were examined in 8 PDAC cell lines in response to inhibition of HA production by treatment with 4-methylumbelliferone (4-MU) and to promotion by treatment with 12-O-tetradecanoyl-phorbol-13-acetate (TPA) or by co-culture with tumor-derived stromal fibroblasts. We also investigated changes in cell motility by adding exogenous HA. Additionally, mRNA expressions of hyaluronan synthases and hyaluronidases were examined using real time RT-PCR. Inhibition of HA by 4-MU significantly decreased the migration, whereas promotion of HA by TPA or co-culture with tumor-derived fibroblasts significantly increased the migration of PDAC cells. The changes in HA production by these treatments tended to be associated with changes in HAS3 mRNA expression. Furthermore, addition of exogenous HA, especially low-molecular-weight HA, significantly increased the migration of PDAC cells. These findings suggest that HA stimulates PDAC cell migration and thus represents an ideal therapeutic target to prevent invasion and metastasis.

An in situ hybridization study of Hyaluronan synthase (Has) mRNA in developing mouse molar and incisor tooth germs

Hyaluronan (HA) is a major constituent molecule in most extracellular matrices and is synthesized by Hyaluronan synthase (Has). In the present study, we examined expression patterns of Has1, -2, -3 mRNA in developing mouse molar and incisor tooth germs from embryonic day (E) 11.5 to postnatal day (P) 7, focusing on Hertwig’s epithelial root sheath (HERS) and the apical bud in particular. Has1 mRNA expression was not detected in all tooth germs examined. Has2 mRNA was expressed in the surrounding mesenchyme from E12.0 to 18.0 in both molar and incisor tooth germs, but disappeared after birth. Meanwhile, Has3 mRNA was exclusively expressed within the enamel organ, especially in the inner enamel epithelium (IEE), stellate reticulum (SR), and stratum intermedium (SI) until the early bell stage at E16.0. Has3 mRNA disappeared as IEE differentiated into differentiating ameloblasts (dABs), but remained in SI until the root developmental stage of the molar tooth germ at P7. Has3 mRNA was also expressed in HERS until P7. In incisors, Has3 mRNA was expressed in the apical bud, especially in the transit-amplifying (TA) cell region from E16.0 to P7, and in the papillary layer (PL) adjacent to the mature enamel. These gene expression patterns suggested that Has3 is the main control factor for prenatal and postnatal HA synthesis of the tooth germ, and may in part regulate crown and root formation of the tooth germ, maintenance of stem cell niches in the apical bud as well as mineral transport in PL.

739 Hyaluronan controls adipogenesis following skin injury

Skin immune defense and repair is a coordinated response to a variety of danger signals and involves the complex interactions of several different cell types. Dermal adipogenesis is a previously unknown but critical event in this process that participates in antimicrobial defense and inflammation. We have previously shown that high-molecular-weight hyaluronan (HMW-HA) undergoes breakdown into small fragments after injury where it can then activate endothelial cells, macrophages and DCs via TLR4. In this study we investigated if HA may also influence adipogenesis and thus regulate the wound repair process. Maturation of 3T3L1 cells into adipocytes was accompanied by increased HMW-HA seen by Gel Electrophoresis and expression of HAS2 mRNA measured by qPCR (p =0.006). Conversely, digestion of HMW-HA by addition of hyaluronidase inhibited differentiation into mature adipocytes as seen by decreased mRNA for zfp521(p=0.02), zfp423(p=0.01) and Adiponectin (p =0.004), as well as decreased accumulation of lipid droplets and enhanced cell proliferation. The inhibition of early adipogenesis was not due to HA fragments since the addition of HA fragments of 6.4kDa, 50kDa, 150kDa and 1000kD had no effect. In vivo, tissue specific expression of hyaluronidase 1 (HYAL1) in mice prior to injury resulted in less mature dermal fat tissue as seen by immunohistochemistry and lower expression of mRNA for C/EBPα (p=0.002) but not Adiponeqtin(p=0.13) or PPARγ(p=0.27). In normal mice, HA immunostaining was lost 3 days following injury coincident with an increase in expression of HAS2 mRNA (p=0.0008) and mRNA for the hyaluronidase KIAA1199 (p=0.01). The loss of HMW-HA in vivo occurred after the expected increase in adipogenesis immediately after injury. Taken together, these results suggest that HA plays a regulatory role during wound repair by controlling dermal adipogenesis. HMW-HA facilitates fat maturation early in the wound repair process, and hyaluronidase action stops this event later in the wound healing process.

Hyaluronan stimulates pancreatic cancer cell motility

Hyaluronan (HA) accumulates in pancreatic ductal adenocarcinoma (PDAC), but functional significance of HA in the aggressive phenotype remains unknown. We used different models to investigate the effect of HA on PDAC cell motility by wound healing and transwell migration assay. Changes in cell motility were examined in 8 PDAC cell lines in response to inhibition of HA production by treatment with 4-methylumbelliferone (4-MU) and to promotion by treatment with 12-O-tetradecanoyl-phorbol-13-acetate (TPA) or by co-culture with tumor-derived stromal fibroblasts. We also investigated changes in cell motility by adding exogenous HA. Additionally, mRNA expressions of hyaluronan synthases and hyaluronidases were examined using real time RT-PCR. Inhibition of HA by 4-MU significantly decreased the migration, whereas promotion of HA by TPA or co-culture with tumor-derived fibroblasts significantly increased the migration of PDAC cells. The changes in HA production by these treatments tended to be associated with changes in HAS3 mRNA expression. Furthermore, addition of exogenous HA, especially low-molecular-weight HA, significantly increased the migration of PDAC cells. These findings suggest that HA stimulates PDAC cell migration and thus represents an ideal therapeutic target to prevent invasion and metastasis.

A novel epigenetic mechanism regulating hyaluronan production in pancreatic cancer cells.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by an abundant stroma enriched with hyaluronan (HA), a major component of extracellular matrix known to play a critical role in tumor progression. The mechanisms that regulate HA synthesis in PDAC are poorly understood. To investigate whether DNA methylation and HA production from PDAC cells are associated, we studied the effect of 5-aza-2'-deoxycitidine (5-aza-dC), an inhibitor of DNA methylation, or DNA methyltransferase 1 (DNMT1) knockdown by small interfering RNA, on the HA production from PDAC cells. HA production into the conditioned medium was evaluated in PDAC cells treated with 5-aza-dC or DNMT1 knockdown. mRNA expression of HA synthase (HAS) genes was investigated by real-time RT-PCR. Treatment of PDAC cells with 5-aza-dC led to a significant increase in the HA production (up to 2.5-fold increase) in all 4 cell lines tested. This enhanced HA production by 5-aza-dC treatment was accompanied by increased mRNA expression of HAS2 and HAS3. Furthermore, increased HA production and HAS2/HAS3 mRNA expression was also observed in PDAC cells by knockdown of DNMT1. These findings provide evidence, for the first time, that epigenetic mechanism is involved in the regulation of HA synthesis in PDAC cells.

Expression of focal adhesion kinase in mouse cumulus-oocyte complexes, and effect of phosphorylation at Tyr397 on cumulus expansion.

We investigated the expression of focal adhesion kinase (FAK) in mouse cumulus-oocyte complexes (COCs), as well as the role of FAK phosphorylation at Tyr397 during oocyte maturation. The effect of inhibiting FAK phosphorylation at Tyr397 during in vitro maturation (IVM) on subsequent fertilization and preimplantation embryo development was also examined. Western blotting analyses revealed that total and Tyr397-phosphorylated FAK were expressed in vivo in both cumulus cells and oocytes. Immunocytochemical studies localized this kinase throughout the cytoplasm of cumulus cells and oocytes; in particular, Tyr397-phosphorylated FAK tended to accumulate in regions where cumulus cells contact each other. Interestingly, the in vivo level of Tyr397 phosphorylation in cumulus cells was significantly lower after compared to before cumulus expansion. Addition of FAK inhibitor 14, which specifically blocks phosphorylation at Tyr397, stimulated oocyte meiotic maturation and cumulus expansion during IVM in the absence of follicle-stimulating hormone (FSH). Reverse-transcriptase PCR showed that the mRNA expression of hyaluronan synthase 2 (Has2), a marker of cumulus expansion, was significantly induced in cumulus cells. Subsequent in vitro fertilization and culture showed that more oocytes developed to the blastocyst stage when they were treated with FAK inhibitor 14 during IVM, although the blastocyst total cell number was lower than in oocytes stimulated with FSH. These results indicate that FAK is involved in the maturation of COCs; specifically, phosphorylation at Tyr397 may regulate cumulus expansion via the expression of Has2 mRNA in cumulus cells, which could affect the developmental competence of oocytes.

Soluble CD40L promotes proliferation of orbital fibroblasts and expression of hyaluronan synthase in patients with thyroid associated ophthalmopathy

Objective To investigate the effects of soluble CD40L(sCD40L)on proliferation of orbital fibroblasts(OFs)and the expression of three types of hyaluronan synthase(HAS)in vitro,so as to explore the role of sCD40 Lin the pathogenesis of thyroid-associated ophthalmopathy(TAO).Methods OFs obtained from 5patients with TAO and 3normal controls were primarily culutred.The effect of different concentrations of sCD40L(6.25,12.5,25,50,100 and 200ng/mL)on proliferation of OFs of different sources were examined by MTS after 48 hexposure.OFs were also cultured with different concentrations of sCD40L(12.5,25,50 and 100ng/mL)for 3,6,12 and 24h,and then the expression levels of HAS1-3mRNA were determined by real-time RT-PCR.Results Treatment with sCD40 Lat concentrations higher than 25ng/mL for 48 h obviously promoted the proliferation of OFs in patients with TAO(P0.05).In contrast,treatment with sCD40 Lonly at concentrations higher than 50ng/mL for 48 hcould promote proliferation of OFs from normal control,and the effect was comparatively weak.HAS3 mRNA expression of OFs in TAO patients was increased after exposed to sCD40L(P0.05),and the increase was in a concentration-and time-dependent manner.Conclusion sCD40 Lcan promote the proliferation of OFs and expression of HAS3 mRNA in patients with TAO,which implies that sCD40 Lplays an important role in the pathogenesis of TAO.