Hyaluronic Acid Expression Research Articles

NADPH Oxidases Regulate CD44 and Hyaluronic Acid Expression in Thrombin-treated Vascular Smooth Muscle Cells and in Atherosclerosis

The intracellular signaling events by which NADPH oxidase-generated reactive oxygen species (ROS) modulate vascular smooth muscle cell (VSMC) function and atherogenesis are yet to be entirely elucidated. We previously demonstrated that NADPH oxidase deficiency decreased atherosclerosis in apoE(-/-) mice and identified adhesion protein CD44 as an important ROS-sensitive gene expressed in VSMC and atherosclerotic lesions. Here, we examined the molecular mechanisms by which NADPH oxidase-generated ROS regulate the expression of CD44 and its principal ligand, hyaluronan (HA), and how CD44-HA interaction affects VSMC proliferation and migration and inflammatory gene expression in apoE(-/-) mice aortas. Thrombin-induced CD44 expression is mediated by transcription factor AP-1 in a NADPH oxidase-dependent manner. NADPH oxidase-mediated ROS generation enhanced thrombin-induced HA synthesis, and hyaluronan synthase 2 expression in VSMC. Hyaluronidase, which generates low molecular weight HA (LMW-HA), is induced in VSMC in a NADPH oxidase-dependent manner and LMW-HA stimulated ROS generation and cell proliferation in wild-type but not p47(phox-/-) VSMC, effects that were enhanced by thrombin pretreatment. Haptotactic VSMC migration toward HA was increased by thrombin in a CD44-dependent manner. HA expression in atherosclerotic lesions and plasma-soluble CD44 and HA levels were higher in apoE(-/-) compared with apoE(-/-)/p47(phox-/-) mice. HA-regulated pro-inflammatory gene expression was higher in apoE(-/-) than apoE(-/-)/p47(phox-/-) mouse aortas. GKT136901, a specific inhibitor of Nox1- and Nox4-containing NADPH oxidase activity, attenuated ROS generation and atherosclerosis and decreased CD44 and HA expression in atherosclerotic lesions. Together, these data suggest that increased CD44 and HA expression and CD44-HA-dependent gene regulation may play a role in atherosclerosis stimulated by NADPH oxidase activation.

Antitumor Activity of Hyaluronic Acid Synthesis Inhibitor 4-Methylumbelliferone in Prostate Cancer Cells

4-Methylumbelliferone (4-MU) is a hyaluronic acid (HA) synthesis inhibitor with anticancer properties; the mechanism of its anticancer effects is unknown. We evaluated the effects of 4-MU on prostate cancer cells. 4-MU inhibited proliferation, motility, and invasion of DU145, PC3-ML, LNCaP, C4-2B, and/or LAPC-4 cells. At IC(50) for HA synthesis (0.4 mmol/L), 4-MU induced >3-fold apoptosis in prostate cancer cells, which could be prevented by the addition of HA. 4-MU induced caspase-8, caspase-9, and caspase-3 activation, PARP cleavage, upregulation of Fas-L, Fas, FADD and DR4, and downregulation of bcl-2, phosphorylated bad, bcl-XL, phosphorylated Akt, phosphorylated IKB, phosphorylated ErbB2, and phosphorylated epidermal growth factor receptor. At IC(50), 4-MU also caused >90% inhibition of NF-kappaB reporter activity, which was prevented partially by the addition of HA. With the exception of caveolin-1, HA reversed the 4-MU-induced downregulation of HA receptors (CD44 and RHAMM), matrix-degrading enzymes (MMP-2 and MMP-9), interleukin-8, and chemokine receptors (CXCR1, CXCR4, and CXCR7) at the protein and mRNA levels. Expression of myristoylated-Akt rescued 4-MU-induced apoptosis and inhibition of cell growth and interleukin-8, RHAMM, HAS2, CD44, and MMP-9 expression. Oral administration of 4-MU significantly decreased PC3-ML tumor growth (>3-fold) when treatment was started either on the day of tumor cell injection or after the tumors became palpable, without organ toxicity, changes in serum chemistry, or body weight. Tumors from 4-MU-treated animals showed reduced microvessel density ( approximately 3-fold) and HA expression but increased terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling-positive cells and expression of apoptosis-related molecules. Therefore, the anticancer effects of 4-MU, an orally bioavailable and relatively nontoxic agent, are primarily mediated by inhibition of HA signaling.

Protective effect of bilberry (Vaccinium myrtillus L.) extracts on cultured human corneal limbal epithelial cells (HCLEC)

The use of bilberry (Vaccinium myrtillus L.) as a food and medicine for improving human vision has a long history all over the world. However, there is lack of convincing evidence from rigorous clinical trials or scientific research. This study investigated the effects of different concentrations of bilberry extracts on the cell viability, cell cycle and the expression of hyaluronic acid and glycosaminoglycans of cultured human corneal limbal epithelial cells. The data showed that bilberry extracts had no cytotoxicity to the corneal limbal epithelial cells at a wide range of concentrations (10(-9)-10(-4) M, equalized to the content of cyanidin-3-O-glucoside). Bilberry extract (10(-6), 10(-5) and 10(-4) M) increased cell viability after 48 h incubation. The number of cells decreased in G(0)/G(1) phase and increased prominently in S and G(2)/M phases after treatment with bilberry extracts at a high concentration (10(-4) M). The expression of glycosaminoglycans increased prominently after incubation with bilberry extracts (10(-7) and 10(-4) M) for 48 h while no significant changes were observed for the expression of hyaluronic acid. The results indicated that bilberry extract may be beneficial for the physiological renewal and homeostasis of corneal epithelial cells.

NADPH Oxidases Regulate CD44 and Hyaluronic Acid Expression in Thrombin-treated Vascular Smooth Muscle Cells and in Atherosclerosis

NADPH Oxidases Regulate CD44 and Hyaluronic Acid Expression in Thrombin-treated Vascular Smooth Muscle Cells and in Atherosclerosis

Extrinsic ageing in the human skin is associated with alterations in the expression of hyaluronic acid and its metabolizing enzymes

Extrinsic skin ageing or 'photoageing', as opposed to intrinsic skin ageing, is the result of exposure to external factors, mainly ultraviolet irradiation. Glycosaminoglycans (GAG) and particularly hyaluronic acid (HA) are major components of the cutaneous extracellular matrix involved in tissue repair. However, their involvement in extrinsic skin ageing remains elusive. In this study, we investigated the expression of HA and its metabolizing enzymes in photoexposed and photoprotected human skin tissue specimens, obtained from the same patient. Total GAG were isolated, characterized using specific GAG-degrading enzymes and separated by electrophoresis on cellulose acetate membranes and polyacrylamide gels. Quantitation of HA in total GAG was performed using ELISA. Gene expression of hyaluronan synthases (HAS), hyaluronidases (HYAL) and HA receptors CD44 and receptor for HA-mediated motility (RHAMM) was assessed by RT-PCR. We detected a significant increase in the expression of HA, of lower molecular mass, in photoexposed skin as compared with photoprotected skin. This increase was associated with a significant decrease in the expression of HAS1 and an increase in the expression of HYAL1-3. Furthermore, the expression of HA receptors CD44 and RHAMM was significantly downregulated in photoexposed as compared with photoprotected skin. These findings indicate that extrinsic skin ageing is characterized by distinct homoeostasis of HA. The elucidation of the role of HA homoeostasis in extrinsic skin ageing may offer an additional approach in handling cutaneous ageing.

Effects of cyclic strain on rat tail tenocytes

Cyclical mechanical strain is considered an important component in flexor tendon cell activation to prevent adhesions and enhance the healing process after tissue injury or surgery, but the biochemical events associated with this remain unclear. To address this, we examined the effects of cyclic tension on the expression of hyaluronic acid, an important lubricant and signal transducer in tendon, on its receptor (CD44), and on total glycosaminoglycan content in rat tail derived tendon fibroblasts in vitro. Tenocytes were plated on fibronectin coated silastic membranes and the cultures were held static or subjected to vacuum induced deformation for a period of 5 min once every 8 h as a model of cyclic mechanical stress. After 24 h medium and cell layers were collected for analyses by product specific ELISA, Western blot, and colorimetric dye-binding assays. Strained tenocytes produced a nearly two-fold increase in hyaluronic acid and a greater than 60% increase in CD44, but had an insignificant effect on total glycosaminoglycan content. Our results predict that high levels of strain may therefore rapidly enhance the expression of hyaluronic acid and cause, albeit still unresolved, downstream effects on CD44 activation, to influence tendon cell activity and enhance the process of tendon repair.

Regulation of Colonic Epithelial Repair in Mice by Toll-Like Receptors and Hyaluronic Acid

The protective component of the host response to dextran sodium sulfate (DSS)-induced colitis in the mouse is mediated through the activation of Toll-like receptor (TLR) 4, the induction of cyclooxygenase (COX)-2, and prostaglandin E(2) production. TLR4 ligands include bacterial lipopolysaccharide and hyaluronic acid, a component of the extracellular matrix. Our hypothesis is that hyaluronic acid, through TLRs, plays a protective role in the host response to DSS-induced colitis. DSS (2.5%) was administered for 7 days in wild-type and MyD88(-/-) mice. The mice also received intraperitoneal hyaluronic acid. The expression of hyaluronic acid, COX-2, and macrophage inflammatory protein (MIP)-2 was evaluated by immunohistochemistry. DSS induced a marked increase in hyaluronic acid in the lamina propria of wild-type but not MyD88(-/-) mice. Treatment with DSS also induced the MyD88-dependent expression of hyaluronic acid synthases 2 and 3, enzymes involved in hyaluronic acid synthesis, in lamina propria macrophages. Exogenous hyaluronic acid induced the expression of tumor necrosis factor alpha, MIP-2, and COX-2 in the colon in a MyD88-dependent manner. In wild-type but not MyD88(-/-), TLR4(-/-), COX-2(-/-) mice, hyaluronic acid was protective against DSS-induced colitis. In wild-type mice, hyaluronic acid was therapeutic in established DSS-induced colitis. Endogenous hyaluronic acid expression is markedly increased in DSS-induced colitis and preserves the epithelium through TLR activation and COX-2 expression. Furthermore, exogenous hyaluronic acid, through the activation of TLRs and the production of prostaglandin E(2) through COX-2, has protective effects in DSS-induced colitis.

Hyaluronan expression and sperm DNA fragmentation as indicators of conventional intracytoplasmic sperm injection (ICSI)

OBJECTIVE: Hyaluronic acid (HA) recently introduced as a basis for selecting sperm with superior maturity and DNA integrity. ICSI may be the only option for infertile men with poor sperm quality. Our aim was to examine the HA expression and DNA fragmentation in infertile couples undergoing ICSI.

Hyaluronic Acid and HYAL-1 in Prostate Biopsy Specimens: Predictors of Biochemical Recurrence

Molecular markers could aid prostate specific antigen, biopsy Gleason sum and clinical stage to provide accurate information on prostate cancer progression. HYAL-1 hyaluronidase and hyaluronic acid staining in prostatectomy specimens predicts biochemical recurrence. We examined whether hyaluronic acid and HYAL-1 staining in biopsy specimens predicts biochemical recurrence and correlates with staining in matched prostatectomy specimens. Biopsy and prostatectomy specimens were obtained from 61 patients with clinically localized prostate cancer from multiple centers, including 23 with (group 1) and 38 without (group 2) biochemical recurrence. Mean followup was 103.1 months. Biotinylated hyaluronic acid binding protein and anti-HYAL-1 antibody were used for hyaluronic acid and HYAL-1 staining, respectively. Staining was graded between 0 and 300 depending on staining intensity and area. HYAL-1 and hyaluronic acid were expressed in tumor cells and stroma, respectively. In biopsy specimens HYAL-1 and hyaluronic acid expression was higher in group 1 than in group 2 (203.9 and 182.1 vs 48.8 and 87.0, respectively, p <0.0001). On univariate analysis hyaluronic acid, HYAL-1, biopsy Gleason and prostate specific antigen significantly predicted biochemical recurrence (p <0.001). On multivariate analysis only HYAL-1 staining independently predicted recurrence with an accuracy of 81.8% (p <0.001). In prostatectomy specimens only HYAL-1 staining correlated with staining in biopsy specimens (Spearman rho = 0.72, p = 0.0002) and predicted biochemical recurrence. To our knowledge this is the first report that HYAL-1 staining in biopsy specimens is an independent predictor of biochemical recurrence. This may be useful when selecting treatment.

Differential glycosaminoglycan expression and hyaluronan homeostasis in juvenile hyaline fibromatosis

Juvenile hyaline fibromatosis (JHF) is a rare autosomal recessive disease characterized histologically by deposition of hyaline material and clinically by multiple skin lesions. Clarification of the molecular and structural changes involved in JHF skin lesions may unravel targets for pharmacotherapy. We sought to investigate the expression of glycosaminoglycans and their metabolizing enzymes in lesional as compared with lesion-free skin tissue specimens in JHF. Glycosaminoglycans were isolated, purified, and fractionated by electrophoresis on cellulose acetate membranes and agarose gels. Hyaluronic acid (HA) was quantitated by enzyme-linked immunosorbent assay and the expression of HA metabolizing enzymes was investigated using reverse transcriptase-polypeptide chain reaction. JHF lesions exhibited significantly less HA and elevated amounts of dermatan sulfate and chondroitin sulfate, whereas gene expression of HA synthase-1 and HA synthase-3 was significantly down-regulated, as compared with lesion-free skin tissue specimens. Because JHF is a rare disease, a limitation to our study was that we collected skin tissue specimens from only one patient. The significant alterations of HA homeostasis in JHF lesions provide further understanding of JHF pathogenesis and may offer a target for pharmacologic intervention to treat the skin lesions associated with JHF.

Synthesis of hyaluronan in oesophageal cancer cells is uncoupled from the prostaglandin–cAMP pathway

Cyclooxygenase-2 (COX2) and hyaluronic acid (HA) are common in tumours and both independently promote tumour progression. Furthermore, COX2-dependent synthesis of prostaglandins (PGs) stimulates HA synthase-1 (HAS1) and HAS2 mRNA expression, together with HA synthesis via the cAMP/protein kinase A pathway in vascular smooth muscle cells. Therefore, the aim of the present study was to elucidate whether COX2-mediated PGs induce transcription of HAS isoforms in cancer cells as well. Human oesophageal squamous cell (OSC) carcinoma specimens were characterized with respect to HA, COX2 and CD44 expression by immunohistochemistry. OSC cell lines (OSC1, OSC2) and HeLa cell lines (D98, H21) were exposed to exogenous PG analoques (100 nmol.L(-1)), etoricoxib (10 micromol.L(-1)) and forskolin (10 micromol.L(-1)). Subsequently, cAMP levels, HA secretion and HAS isoform expression were determined by elisa and real-time RT-PCR (reverse transcriptase polymerase chain reaction) respectively. COX2, HA and CD44 were detected immunohistochemically in >90% of human oesophageal tumour samples. Under basal conditions, OSC1 and OSC2 cells express HAS2 and HAS3, COX2 and Galpha(s)-coupled EP(2) and EP(4) PG receptors. Neither stimulation with the PGI(2) analogue, iloprost, addition of exogenous PGE(2) nor forskolin induced HAS1 or HAS2 mRNA expression in OSC1 and OSC2 cells. Furthermore, in HeLa cells after induction of COX2 by tumour necrosis factor alpha and subsequent PGE(2) release, inhibition of COX2 by etoricoxib did not affect HAS expression or HA secretion. We conclude that in oesophageal and HeLa cancer cells, HAS1/2 expression was not responsive to the PG/cAMP pathway.

Concentration and distribution of hyaluronic acid in mouse uterus throughout the estrous cycle

To quantify and study the immunoexpression of hyaluronic acid (HA) in the uterine horns of the mouse throughout the estrous cycle phases. Experimental study using an ELISA-like fluorometric assay to quantify HA and an avidin-biotin immunoperoxidase method using biotinylated hyaluronan-binding protein for histochemical studies. University-based laboratory. Forty regularly cycling adult female mice were divided into four groups according to the diagnosed phase of the cycle: proestrus, estrus, metaestrus, and diestrus. None. Histologic samples of the uterine horns. Immunohistochemical reaction was evaluated by detection of HA and CD44 distribution within the uterine horn. Tissue HA content was determined through an ELISA-like fluorometric assay with the same hyaluronan-binding protein and with europium-labeled streptavidin. The immunohistochemical HA and CD44 reactions were most intense during diestrus, mainly below the luminal epithelium. HA was strongly stained in the connective tissue near the myometrium layer during metaestrus. The biochemical data showed that the highest concentration of HA in uterine horns occurred during diestrus (4053.0 +/- 651.4 ng/g dry tissue) compared with other phases. Our data show that the expression of HA in mouse uterine horns is highest during the diestrous phase. The fluctuations of HA in the mouse uterus during the estrous phase may be related to the varying estrogen and P levels during the cycle and may be important as far as embryo implantation is concerned.

Increased hyaluronic acid content in idiopathic pulmonary arterial hypertension

Idiopathic pulmonary arterial hypertension (IPAH) is a fatal disease characterised by elevated blood pressure in the pulmonary circulation. Initial vasoconstriction, proliferation of pulmonary arterial smooth muscle cells (PASMC) and increased deposition of extracellular matrix (ECM) contribute to pathological remodelling of pulmonary arterioles in IPAH. Glycosaminoglycans (GAGs), components of the ECM, control cellular proliferation and differentiation, but their expression in IPAH remains elusive. In the present study, GAG expression was investigated in the lungs of patients with IPAH or control transplant donors, and expression and localisation of GAG-metabolising enzymes were analysed in vivo and in vitro. A significant increase in the expression of hyaluronic acid (HA) was detected in IPAH lungs, associated with increased hyaluronan synthase (Has)1 and decreased hyaluronoglucosaminidase 1 gene expression, as assessed by quantitative RT-PCR and Western blotting. HAS1 protein localised to PASMC in vivo and increased HA deposition was observed in remodelled pulmonary arteries in IPAH. Transforming growth factor-beta1, a profibrotic growth factor, led to increased HA secretion and HAS1 expression in primary PASMC. The results demonstrate an increased hyaluronic acid content in idiopathic pulmonary arterial hypertension lungs, associated with increased hyaluronan synthase 1 and decreased hyaluronoglucosaminidase 1 gene expression. Synergistic regulation of glycosaminoglycan-metabolising enzymes in favour of accumulation may, thus, regulate pathological vascular remodelling in idiopathic pulmonary arterial hypertension lungs.

Roles of Vitamin a and Macula Flava in Maintaining Vocal Folds

Vitamin A plays important roles in development, growth, and regeneration. Vitamin A-storing stellate cells have been identified in several organs. The functional roles of vitamin A in the vocal folds are still unknown, although vitamin A-storing vocal fold stellate cells have been observed in the macula flava of human and rat vocal folds. The purpose of this study was to investigate the roles of vitamin A in vocal folds. Vitamin A-deficient rats were generated, and the vocal folds were examined histologically. Messenger RNA was extracted from the vocal folds and analyzed by real-time polymerase chain reaction. Immunohistochemical analysis of normal vocal folds revealed expression of retinoic acid receptor a in vocal fold stellate cells. The cells in the macula flava of vitamin A-deficient rats showed a larger nucleus/cytoplasm ratio than did those of vitamin A-sufficient rats, but messenger RNA expression of major extracellular matrix components in the macula flava of vitamin A-deficient rats did not present a remarkable change except for procollagen type I. Expression of hyaluronic acid, collagen types I and III, and elastin did not show a significant change in vitamin A-deficient rat vocal folds. These results indicate that vitamin A is not essential to maintaining the extracellular matrix of normal adult vocal folds, although vocal fold stellate cells participate in vitamin A storage.

Exogenous mesenchymal stem cells localize to the kidney by means of CD44 following acute tubular injury

Mesenchymal stem cells (MSC) were recently shown to migrate to injured tissues when transplanted systemically. The mechanisms underlying the migration and homing of these cells is, however, unclear. In this study, we examine the role of CD44 and its major ligand, hyaluronic acid, in the trafficking of intravenously injected MSC in the glycerol-induced mouse model of acute renal failure (ARF). In vitro, hyaluronic acid promoted a dose-dependent migration of the stem cells that was inhibited by an anti-CD44 blocking monoclonal antibody. In vivo, stem cells injected into mice with ARF migrated to the injured kidney where hyaluronic acid expression was increased. Their presence correlated with morphological and functional recovery. Renal localization of the MSC was blocked by pre-incubation with the CD44 blocking antibody or by soluble hyaluronic acid. Stem cells derived from CD44 knockout mice did not localize to the injured kidney and did not accelerate morphological or functional recovery. Reconstitution by transfection of CD44 knockout stem cells with cDNA encoding wild-type CD44, but not a loss of function CD44 unable to bind hyaluronic acid, restored in vitro migration and in vivo localization of the cells to injured kidneys. We suggest that CD44 and hyaluronic acid interactions recruit exogenous MSC to injured renal tissue and enhance renal regeneration.

HAS1 expression in bladder cancer and its relation to urinary HA test

Hyaluronic acid (HA) levels are elevated in bladder cancer tissues and regulate tumor growth and progression. Urinary HA levels measured by the HA test are an accurate marker for bladder cancer. In cells, HA is synthesized by one of the 3 HA-synthase(s) i.e., HAS1, HAS2 and HAS3. In this study, we examined HAS1 expression in bladder cancer cells and tissues. Real-time RT-PCR and northern blot analyses showed that HAS1 transcript levels are elevated 5- to 10-fold in bladder cancer tissues, when compared with normal tissues (p < 0.001). Among the 3 HAS1 splice variants, only HAS1-va was expressed in bladder tissues, but the expression was significantly lower than the wild type HAS1 transcript. Increased HAS1 expression in bladder tumor tissues correlated with increased tissue HA levels (p < 0.001). Size of the large HA species (2.0 x 10(6) D) present in bladder tissues was consistent with the size of the HA polymer synthesized by HAS1. The amount of HA produced by bladder cancer cell lines correlated with the expression of HAS1 protein. Immunohistochemical analyses of bladder tumor tissues showed that HAS1 and HA expression had 79-88% sensitivity and 83.3-100% specificity. Both HAS1 and HA expression in bladder cancer tissues correlated with a positive HA urine test (p < 0.001). HAS1 expression correlated with tumor recurrence, prior treatment (p < 0.05) and possibly disease progression (p = 0.058). Therefore, elevated HAS1 expression in bladder tumor tissues contributes to a positive HA urine test and may have some prognostic potential.

The Role of Hyaluronic Acid in Normal and Perturbed Hemopoietic Stem Cell Biology.

Considerable evidence supports the proposal that the localisation of hemopoiesis to the bone marrow (BM) involves developmentally regulated adhesive interactions between primitive hemopoietic stem cells (HSC) and the hemopoietic microenvironment of the marrow. Previous studies in our laboratory demonstrate that HSC reside within an endosteal stem cell niche, and identified several key molecules that play critical roles in their attraction to, and retention and regulation within this region. We have previously described Hyaluronic acid (HA) as one of these key molecules and shown that human and murine HSC synthesise and express HA. HSC express the 3 HAS genes and synthesis of this glycosaminoglycan by HSC as well as by cells within the hemopoietic microenvironment is critical for HSC engraftment and for regulating the HSC pool in vivo. In addition, analysis of HAS 1 and 3 knockout mice identified HA synthesised by HAS 3 to be responsible for these effects. In the absence of HAS-3 synthase the endosteal region is devoid of HA, and the hemopoietic microenvironment is significantly impaired in its ability to attract and support HSC post-transplant as well as regulate the HSC pool in vivo. Furthermore, transplanted HSC isolated from HAS-3−/− mice have a reduced ability to lodge within the endosteal region and reconstitute hemopoiesis. In vitro, binding of HA by a surrogate ligand, HABP, also has a negative regulatory effect of HSC proliferation and differentiation. Together these data suggest that HA on the surface of HSC is critical in both their lodgement and subsequent quiescence within the hemopoietic stem cell niche. Analysis of a cohort of childhood ALL samples revealed a significant correlation between the length of first complete remission and HA synthesis, cell surface HA expression, HAS-3 expression, the distribution of leukemic cells following transplantation and the development of disease in a murine model. In addition, anti-sense inhibition of HAS-3 expression in the Pre-B ALL cell line NALM6, resulted in a significantly reduced time to onset of leukaemia within a NOD/SCID murine model. Furthermore, retroviral mediated overexpression of HAS-3 in this cell line resulted in 2.5-fold increase in mRNA, a 20-fold increase in cell surface HA and a significant decrease in the proliferation potential of these cells in culture. Furthermore, following transplantation of HAS-3 overexpressing NALM6 cells into NOD/SCID recipients there was a significant delay in the onset of leukemia compared to that seen following the transplant of unmanipulated NALM6 cells. This demonstrates a primary role of HAS-3 in the onset and progression of common ALL and that HA expression levels may provide a novel prognostic indictor for this leukaemia. Furthermore, initial studies of HA expression in other leukemic bone marrow samples revealed that cells from AML, CML and CLL also exhibit increased levels of HA, with a correlation between disease progression and HA synthesis and expression; HA levels were elevated at diagnosis, decreasing in remission and increasing again at relapse. Overall, our data is strongly suggestive of a key role for this polysaccharide in both normal and aberrant hemopoietic stem cell biology.

Use of DNA Arrays to Identify a Mutation in the Negative Regulator,csrR,Responsible for the High Virulence of a Naturally Occurring Type M3 Group A Streptococcus Clinical Isolate

We previously reported that type M3 group A streptococcus (GAS) showed a wide range of 50% lethal dose values in mice. Analysis using DNA arrays indicated that the most virulent strain, M3-f, expressed significantly higher levels of the products of several virulence genes than did the other M3 isolates. Sequencing of the csrS, csrR, luxS, and rgg genes in the isolates showed that the M-3f csrR gene contained a specific point mutation. Disruption of wild-type (wt) csrR in an M3 strain increased its virulence and the expression of hyaluronic acid, whereas complementation with wt but not type M3-f csrR attenuated these changes. Expression experiments showed that type M3-f CsrR counteracted the effects of wt CsrR. Although wt CsrR bound to the hasA promoter region, type M3-f CsrR did not. Thus, the high virulence of the type M3-f strain is associated with the decreased binding of type M3-f CsrR to its target sequences.

Distribution of hyaluronic acid in fetal Skin

目的 通过研究不同胎龄胎儿皮肤中透明质酸的分布,观察其变化规律,从而探讨其分布与无瘢痕愈合之间的关系,为临床上瘢痕的预防及治疗提供理论依据.方法自4所医院妇产科取3～8个月龄的引产胎儿32例,取颌面部、背部、腹部及大腿内侧4处皮肤,进行免疫组织化学染色,观察透明质酸在皮肤中的分布.结果3个月龄胎儿皮肤中表皮层透明质酸染色阳性,4、5个月龄胎儿皮肤表皮上层染色阳性,真皮染色弱阳性,6～8个月龄胎儿皮肤中透明质酸染色表皮为阴性,真皮层阳性,随胎儿成熟度的提高透明质酸分布发生了明显的变化.不同部位皮肤之间透明质酸分布无明显差别.结论透明质酸分布随胎龄增长由表皮层向真皮层转移,透明质酸分布与无瘢痕愈合之间可能存在一定联系。

Roles of and correlation between a-smooth muscle actin, CD44, hyaluronic acid and osteopontin in crescent formation in human glomerulonephritis

alpha-Smooth muscle actin (SMA), CD44, hyaluronic acid (HA) and osteopontin (OPN) are involved in crescent formation; however, the correlation between these molecules during the formation and progression of the crescents in human glomerulonephritis (GN) has not been fully evaluated. To investigate the expression of alpha-SMA, CD44, HA, OPN and CD68 renal biopsy specimens from 14 patients with crescentic GN were examined by immunohistochemistry. All crescents were separated into cellular, fibrocellular and fibrous. The extent of staining in each crescent was scored semiquantitatively. The change in the expression of each molecule and its correlation with other molecules during the formation and progression of the crescents were estimated statistically. The expression of alpha-SMA was significantly up-regulated in the fibrocellular crescents compared with that in the cellular and fibrous crescents. The expression of CD44, OPN and CD68 was significant in the cellular crescents compared with that in the fibrocellular and fibrous crescents. The deposition of HA in the three groups of crescents was high level. However, that of HA was not significant among three groups of crescent. The expression of CD44 in the cellular crescents correlated significantly with the expression of OPN and CD68, and the deposition of HA in the cellular crescents. The expression of OPN in the cellular crescents correlated with the deposition of HA and the expression of CD68 in the cellular crescents. The expression of alpha-SMA in the cellular and fibrocellular crescents correlated with the deposition of HA in the cellular and fibrocellular crescents. The expression of CD44, HA, OPN and CD68 was up-regulated at the early stage of the crescent formation in human crescentic GN. Moreover, myofibroblasts and cell-matrix interactions mediated by the CD44-OPN and CD44-HA receptor-ligand pairs may play important roles in the formation and progression of the crescents.