High-Molecular-Weight Hyaluronan Is a Hippo Pathway Ligand Directing Cell Density-Dependent Growth Inhibition via PAR1b. Ooki T et al. (2019) High-molecular-weight hyaluronan, a major component of the extracellular matrix, is anti-oncogenic, whereas low-molecular-weight hyaluronan is pro-oncogenic, though the mechanisms underlying the size-dependent opposite bioactivities of hyaluronan remain uncertain. We show here that treatment with high-molecular-weight hyaluronan stimulates tumor-suppressive Hippo signaling in breast epithelial cells. Mechanistically, clustering of the CD44 extracellular domain by high-molecular-weight hyaluronan leads to recruitment of the polarity-regulating kinase PAR1b by the CD44 intracellular domain, which results in disruption of the Hippo signaling-inhibitory PAR1b-MST complex. Once liberated from PAR1b, MST activates Hippo signaling. Conversely, low-molecular-weight hyaluronan, which is produced by hyaluronidase-mediated degradation of high-molecular-weight hyaluronan, inhibits Hippo signaling by competing with high-molecular-weight hyaluronan for CD44 binding. Triple-negative breast cancers with higher hyaluronidase-2 expression show poorer prognosis than those with lower hyaluronidase-2 expression. Consistently, decreased hyaluronidase-2 is associated with reduced tumorigenicity in a tumor xenograft model. Hence, perturbation of high-molecular-weight hyaluronan-mediated Hippo signaling activation contributes to cancer aggressiveness.//////////////////Molecular organization and mechanical properties of the hyaluronan matrix surrounding the mammalian oocyte. Salustri A et al. (2018) Successful ovulation and oocyte fertilization are essential prerequisites for the beginning of life in sexually reproducing animals. In mammalian fertilization, the relevance of the protein coat surrounding the oocyte plasma membrane, known as zona pellucida, has been widely recognized, while, until not too long ago, the general belief was that the cumulus oophorus, consisting of follicle cells embedded in a hyaluronan rich extracellular matrix, was not essential. This opinion was based on in vitro fertilization procedures, in which a large number of sperms are normally utilized and the oocyte can be fertilized even if depleted of cumulus cells. Conversely, in vivo, only very few sperm cells reach the fertilization site, arguing against the possibility of a coincidental encounter with the oocyte. In the last two decades, proteins required for HA organization in the cumulus extracellular matrix have been identified and the study of fertility in mice deprived of the corresponding genes have provided compelling evidence that this jelly-like coat is critical for fertilization. This review focuses on the advances in understanding the molecular interactions making the cumulus environment suitable for oocyte and sperm encounter. Most of the studies on the molecular characterization of the cumulus extracellular matrix have been performed in the mouse and we will refer essentially to findings obtained in this animal model.//////////////////
Hyaluronic acid binds to CD44, Receptor for HA-mediated motility (RHAMM) and intercellular adhesion molecule-1 (ICAM-1) as well as the lymphatic vessel endothelial hyaluronan receptor 1 (LYVE1).////////////Organization of the expanded cumulus-extracellular matrix in preovulatory follicles: a role for inter-alpha-trypsin inhibitor. Nagyova E et al. (2015) It has been shown that following endogenous gonadotropin surge, oocyte-cumulus complexes (OCC) synthesize hyaluronan (HA) in a process called cumulus expansion. During this process, HA associates with proteins and proteoglycans to form the expanded HA-rich oocyte-cumulus extracellular matrix (ECM), where the heavy chains of the serum derived inter-α-trypsin inhibitor family (IαI) bind covalently to HA. No study has been performed on the occurrence and regulation of this process during oocyte maturation in species other than mouse and pig, although, the heavy chains (of IαI)-HA complex was purified from human amniotic membrane. The present review pointing out that: 1/ formation of expanded HA-rich oocyte-cumulus ECM is dependent on the presence of IαI molecules, 2/ the heavy chains of IαI molecules identified in the serum are covalently linked to HA during cumulus expansion in mouse and pig, 3/ the family of IαI molecules can freely cross the blood-follicle barrier, and the follicular fluid collected at any stage of folliculogenesis can be successfully used instead of serum to form expanded cumulus ECM in pig, and 4/ proteins of the IαI family can affect reproductive process by modulating the expression of a large number of cellular genes during a preovulatory period. Finally, this review provides clear evidence that IαI family members present in the serum or follicular fluid become responsible for cumulus expansion, as without these proteins, expanded cumulus HA-rich ECM is not formed and HA is released into medium. Keywords: cumulus expansion, cumulus-extracellular matrix, hyaluronan, inter-α-trypsin inhibitor.//////////////////
NCBI Summary:
Hyaluronan or hyaluronic acid (HA) is a high molecular weight unbranched polysaccharide synthesized by a wide variety of organisms from bacteria to mammals, and is a constituent of the extracellular matrix. It consists of alternating glucuronic acid and N-acetylglucosamine residues that are linked by beta-1-3 and beta-1-4 glycosidic bonds. HA is synthesized by membrane-bound synthase at the inner surface of the plasma membrane, and the chains are extruded through pore-like structures into the extracellular space. It serves a variety of functions, including space filling, lubrication of joints, and provision of a matrix through which cells can migrate. HA is actively produced during wound healing and tissue repair to provide a framework for ingrowth of blood vessels and fibroblasts. Changes in the serum concentration of HA are associated with inflammatory and degenerative arthropathies such as rheumatoid arthritis. In addition, the interaction of HA with the leukocyte receptor CD44 is important in tissue-specific homing by leukocytes, and overexpression of HA receptors has been correlated with tumor metastasis. HAS1 is a member of the newly identified vertebrate gene family encoding putative hyaluronan synthases, and its amino acid sequence shows significant homology to the hasA gene product of Streptococcus pyogenes, a glycosaminoglycan synthetase (DG42) from Xenopus laevis, and a recently described murine hyaluronan synthase. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2014]
General function
Enzyme
Comment
Intramuscular Autotransplantation of Vitrified Rat Ovary Encapsulated with Hyaluronic Acid Hydrogel. Akhavan Taheri M et al. (2016) Acceleration of revival of ovarian function and maintaining of follicular reserve is mandatory after transplantation of cryopreserved ovarian tissue. In this study, hyaluronic acid hydrogel was used as a scaffold to improve restoration of ovarian estrous cycle and follicular preservation. Mature (∼8 weeks old) female Wistar rats with normal estrous cycles were divided in two groups: A: autotransplanted vitrified ovarian tissue without hyaluronic acid (HA), and B: autotransplanted vitrified ovarian tissue encapsulated with HA. Bilateral ovariectomy was performed in the diestrus stage; then ovaries were vitrified, warmed, and autotransplanted intramuscularly. Daily vaginal monitoring was performed until re-initiation of first full estrous cycle. Thereafter, follicular preservation, fibrosis, and apoptosis incidence were assessed histologically and immunohistochemically. The serum follicle stimulating hormone (FSH) levels were also accessed and compared for normal and ovariectomized rats. Re-initiation of first full cycle, atretic follicles, apoptotic index, and area of fibrosis in group A were approximately similar to group B. However, the total numbers of intact follicles were significantly lower in group B than group A. Moreover, the level of FSH in both experimental groups and normal rats was similar and in group B reduced significantly compared to the ovariectomized rats. Hyaluronic acid hydrogel did not show any negative effect on restoration of estrous cycle, but could not support follicular preservation after autotransplantation.//////////////////
Cellular localization
Plasma membrane
Comment
Ovarian function
Antrum/Follicular fluid formation, Cumulus expansion, Oocyte maturation, Early embryo development
Comment
Hyaluronic acid prevents immunosuppressive drug-induced ovarian damage via up-regulating PGRMC1 expression. Zhao G et al. (2015) Chemotherapy treatment in women can frequently cause damage to the ovaries, which may lead to primary ovarian insufficiency (POI). In this study, we assessed the preventative effects of hyaluronic acid (HA) in immunosuppressive drug-induced POI-like rat models and investigated the possible mechanisms. We found that HA, which was reduced in primary and immunosuppressant-induced POI patients, could protect the immunosuppressant-induced damage to granulosa cells (GCs) in vitro. Then we found that HA blocked the tripterygium glycosides (TG) induced POI-like presentations in rats, including delayed or irregular estrous cycles, reduced 17 beta-estradiol(E2) concentration, decreased number of follicles, destruction of follicle structure, and damage of reproductive ability. Furthermore, we investigated the mechanisms of HA prevention effects on POI, which was associated with promotion of GC proliferation and PGRMC1 expression. In conclusion, HA prevents chemotherapy-induced ovarian damage by promoting PGRMC1 in GCs. This study may provide a new strategy for prevention and treatment of POI.//////////////////
Effect of hyaluronan on developmental competence and quality of oocytes and obtained blastocysts from in vitro maturation of bovine oocytes. Opiela J 2014 et al.
The objective of the present study was to evaluate the effect of hyaluronan (HA) during IVM on meiotic maturation, embryonic development, and the quality of oocytes, granulosa cells (GC), and obtained blastocysts. COCs were matured in vitro in control medium and medium with additional 0.035% or 0.07% of exogenous HA. The meiotic maturity did not differ between the analysed groups. The best rate and the highest quality of obtained blastocysts were observed when 0.07% HA was used. A highly significant difference (P < 0.001) was noted in the mean number of apoptotic nuclei per blastocyst and in the DCI between the 0.07% HA and the control blastocysts (P < 0.01). Our results suggest that addition of 0.035% HA and 0.07% HA to oocyte maturation media does not affect oocyte nuclear maturation and DNA fragmentation. However, the addition of 0.07% HA during IVM decreases the level of blastocysts DNA fragmentation. Finally, our results suggest that it may be risky to increase the HA concentration during IVM above 0.07% as we found significantly higher Bax mRNA expression levels in GC cultured with 0.07% HA. The final concentration of HA being supplemented to oocyte maturation media is critical for the success of the IVP procedure.
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Induction of Oocyte Maturation by Hyaluronan-CD44 Interaction in Pigs. [Yokoo M et al. In most mammals, the oocyte is surrounded with compact multilayers of cumulus cells; these form cumulus-oocyte complexes (COCs). During oocyte maturation, the COCs dramatically expand and this is termed 'cumulus expansion'. We have previously demonstrated that cumulus expansion is the result of hyaluronan synthesis and accumulation in the extracellular space between cumulus cells in the COCs and that hyaluronan accumulation within the COCs affects oocyte maturation. We have also demonstrated that CD44, the principal hyaluronan receptor, is expressed in the COCs during cumulus expansion and that the interaction between hyaluronan and CD44 appears to be closely related to gap junctional communication of the COCs during the process of meiotic resumption. Based on our previous studies, we review herein that the physiological significance and the molecular mechanism of cumulus expansion for porcine oocyte maturation.
Formation of the Ovarian Follicular Antrum and Follicular Fluid. Rodgers RJ et al. The formation of the follicular antrum and fluid has received scant attention from researchers and yet both are important processes in follicular development. The central hypothesis on follicular fluid formation suggests that production by granulosa cells of hyaluronan and the chondroitin sulfate proteoglycan versican generates an osmotic gradient. This gradient draws in fluid derived from the thecal vasculature. Inter-alpha-trypsin inhibitor is also present in follicular fluid of species with large follicles, and inter-alpha-trypsin inhibitor and versican could additionally bind or cross-link with hyaluronan, resulting in the retention of these molecules within the follicular antrum. In mice inter-alpha-trypsin inhibitor, derived from serum, is not present in the follicular antrum until after the LH surge showing that there are clearly species differences. Barriers to the movement of fluid across the membrana granulosa are apparently minimal as even relatively large serum proteins are present in follicular fluid. Despite the relative permeability of the follicular wall aquaporins are present in granulosa cells and could be actively involved in the transport of water into the follicle. The formation of an antrum also requires movement of granulosa cells relative to each other to allow the fluid to accumulate. This presumably involves remodeling of cell-cell junctions and in species with small follicles may involve death of centrally located granulosa cells. Remodeling of the stroma and thecal layers also accompanies growth and expansion of the antrum, and presumably involves similar processes that accompany growth of other glands.
Expression regulated by
FSH, LH
Comment
Found in an ovulation array.
Ovarian localization
Granulosa, Theca
Comment
Localisation and endocrine control of hyaluronan synthase (HAS) 2, HAS3 and CD44 expression in sheep granulosa cells. Chavoshinejad R et al. (2014) The aim of the present study was to investigate the hormonal regulation of hyaluronan (HA) components in sheep granulosa cells. HA components are present in the reproductive tract and have a range of physical and signalling properties related to reproductive function in several species. First, abattoir-derived ovaries of sheep were used to determine the localisation of HA synthase (HAS) 1-3 and CD44 proteins in antral follicles. Staining for HAS1-3 and CD44 proteins was most intense in the granulosa layer. Accordingly, the expression of HAS2, HAS3 and CD44 mRNA was measured in cultured granulosa cells exposed to 0-50ngmL-1 of 17?-oestradiol and different combinations of oestradiol, gonadotropins, insulin-like growth factor (IGF)-1 and insulin for 48-96h (1ngmL-1 FSH, 10ngmL-1 insulin, 10ngmL-1 IGF-1, 40ngmL-1 E2 and 25ngmL-1 LH.). mRNA expression was quantified by real-time polymerase chain reaction using a fold induction method. The results revealed that the hormones tested generally stimulated mRNA expression of the genes of interest in cultured granulosa cells. Specifically, oestradiol, when combined with IGF-1, insulin and FSH, stimulated HAS2 mRNA expression. Oestradiol and LH had synergistic effects in increasing HAS3 mRNA expression. In conclusion, we suggest that the hormones studied differentially regulate HAS2, HAS3 and CD44 in ovine granulosa cells in vitro. Further work is needed to address the signalling pathways involved.//////////////////
Involvement of hyaluronan synthesis for ovarian follicle growth in rats. Takahashi N 2013 et al.
Most previous studies of ovarian HA have focused on mature antral follicles or corpora lutea, but scarcely on small preantral follicles. Moreover, the origin of follicular HA is unknown. To clarify the localization of HA and its synthases in small growing follicles, involvement of HA in follicle growth and gonadotropin regulation of HA synthase Has gene expression, perinatal, immature and adult ovaries of Wistar-Imamichi rats were examined histologically, biochemically and by in vitro follicle culture. HA was detected in the extracellular matrix of granulosa and theca cell layers of primary follicles and more advanced follicles. Ovarian HA accumulation ontogenetically started in the sex cords of perinatal animals, and its primary site shifted to the intrafollicular region of primary follicles within 5 days after birth. Messenger RNAs for Has1-3 were expressed in ovaries from perinatal, prepubertal and adult rats, and the expression levels of Has1 and Has2 genes were modulated during the estrous cycle in adults and following administration of exogenous gonadotropins in immature acyclic rats. Has1 and Has2 mRNAs were predominantly localized in the theca and granulosa cell layer of growing follicles, respectively. Treatments with chemicals that are known to reduce ovarian HA induced follicular atresia. More directly, addition of Streptomyces hyaluronidase, which specifically degrades HA, induced the arrest of follicle growth in an in vitro culture system. These results indicate that gonadotropin-regulated HA synthesis is involved in normal follicle growth.
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