Regulation and roles of the hyaluronan system in mammalian reproduction.

Ali A Fouladi-Nashta,Waleed F Marei,Kabir A Raheem,Geraldine M Hartshorne,Fataneh Ghafari

doi:10.1530/rep-16-0240

Abstract

Hyaluronan (HA) is a non-sulphated glycosaminoglycan polymer naturally occurring in many tissues and fluids of mammals, including the reproductive system. Its biosynthesis by HA synthase (HAS1-3) and catabolism by hyaluronidases (HYALs) are affected by ovarian steroid hormones. Depending upon its molecular size, HA functions both as a structural component of tissues in the form of high-molecular-weight HA or as a signalling molecule in the form of small HA molecules or HA fragments with effects mediated through interaction with its specific cell-membrane receptors. HA is produced by oocytes and embryos and in various segments of the reproductive system. This review provides information about the expression and function of members of the HA system, including HAS, HYALs and HA receptors. We examine their role in various processes from folliculogenesis through oocyte maturation, fertilisation and early embryo development, to pregnancy and cervical dilation, as well as its application in assisted reproduction technologies. Particular emphasis has been placed upon the role of the HA system in pre-implantation embryo development and embryo implantation, for which we propose a hypothetical sequential model.

Highlights

Hyaluronan (HA), known as hyaluronic acid or hyaluronate, is a high-molecular-weight anionic member of a group of macromolecules called glycosaminoglycans (GAGs) that constitute the components of the extracellular matrix (ECM) in all animal tissues
HA is the simplest of all the GAGs and has a number of unique properties that distinguish it from other GAGs. (i) It is nonsulphated, (ii) it is a linear polysaccharide of thousands of repeated units of alternating d-glucuronic acid and N-acetylglucosamine (Weissmann et al 1954), (iii) it is synthesised at the plasma membrane rather than in the Golgi apparatus (Prehm 1984), (iv) it is extruded into ECM via the cell surface as it is synthesised (Tammi et al 2002) and (v) HA is not restricted to the ECM, rather, its intracellular localisation has been reported (Contreras-Ruiz et al 2011)
We recently reported the expression of hyaluronan synthases (HAS) and CD44, which were mainly localised in the granulosa cells (GCs) (Chavoshinejad et al 2014)

Summary

Introduction

Hyaluronan (HA), known as hyaluronic acid or hyaluronate, is a high-molecular-weight anionic member of a group of macromolecules called glycosaminoglycans (GAGs) that constitute the components of the extracellular matrix (ECM) in all animal tissues. HA is expressed at different stages of pre-implantation embryo development (Marei et al 2013, cow).

Results

Conclusion