Impaired Fertility in Female Mice Lacking Urinary Trypsin Inhibitor

Fibroblasts are central to wound healing and fibrosis through TGF␤1-triggered differentiation into contractile, ␣-smooth muscle actin (␣-SMA)-positive myofibroblasts. This is mediated by accumulation of a pericellular matrix of hyaluronan (HA) and the HA-dependent co-localization of CD44 with the epidermal growth factor receptor (EGFR). Interactions of HA with hyaladherins, such as inter-␣-inhibitor (I␣I) and tumor necrosis factor-stimulated gene-6 (TSG-6), are also essential for differentiation. This study investigated the mechanisms involved. TSG-6 and ␣-SMA had different kinetics of induction by TGF␤1, with TSG-6 peaking before ␣-SMA. Si CD44 or EGFR inhibition prevented differentiation but had no effect on TSG-6 expression. TSG-6 was essential for differentiation, and mAb A38 (preventing I␣I heavy chain (HC) transfer), HA-oligosaccharides, cobalt, or Si bikunin prevented TSG-6 activity, preventing differentiation. A38 also prevented the EGFR/CD44 association. This suggested that TSG-6/I␣I HC interaction was necessary for the effect of TSG-6 and that HC stabilization of HA initiated the CD44/EGFR association. The newly described HC5 was shown to be the principal HC expressed, and its cell surface expression was prevented by siRNA inhibition of TSG-6 or bikunin. HC5 was released by hyaluronidase treatment, confirming its association with cell surface HA. Finally, HC5 knockdown by siRNA confirmed its role in myofibroblast differentiation. The current study describes a novel mechanism linking the TSG-6 transfer of the newly described HC5 to the HA-dependent control of cell phenotype. The interaction of HC5 with cell surface HA was essential for TGF␤1-dependent differentiation of fibroblasts to myofibroblasts, highlighting its importance as a novel potential therapeutic target.The fibroblast is the most abundant cell type in normal connective tissues. It plays a central role in the synthesis, degradation, and remodeling of extracellular matrix both in health and in disease. At sites of tissue damage and in the context of wound healing, activated fibroblasts, termed myofibroblasts, with a contractile phenotype, characterized by the expression of the smooth muscle isoform of ␣-actin (␣-SMA), 3 are essential for the synthesis of a collagen-rich scar, providing the force for wound contraction (1). During a healing response, myofibroblasts are a transient cell population (2). Myofibroblasts are also the major effectors of fibrosis; their persistent presence has been established as the best marker of numerous types of progressive organ dysfunction, such as that seen in chronic renal failure of various etiologies (3-7), liver disease (8), and pulmonary fibrosis (9).The cytokine TGF␤1 is a well recognized mediator of progressive tissue fibrosis, and in vitro and in vivo evidence suggests that it is the primary driving force in fibroblast-myofibroblast phenotypic activation (10, 11). The sequence of events leading up to this transformation is being increasingly characterized at a molecular level in an attempt to understan...

Section: Discussionmentioning

confidence: 99%

Tumor Necrosis Factor-stimulated Gene 6 (TSG-6)-mediated Interactions with the Inter-α-inhibitor Heavy Chain 5 Facilitate Tumor Growth Factor β1 (TGFβ1)-dependent Fibroblast to Myofibroblast Differentiation

Martin

Midgley

Meran

et al. 2016

“…The stabilization of the matrix by these molecules is essential for cumulus expansion and ovulation. Gene-targeting experiments in mice have shown multiple female reproductive defects that include reduced ovulation, defective cumulus expansion, and fertilization failure in the absence of these factors (57)(58)(59)(60)(61).…”

Section: Discussionmentioning

confidence: 99%

Cyclooxygenase-2-derived Prostaglandin E2 Directs Oocyte Maturation by Differentially Influencing Multiple Signaling Pathways

Takahashi

Morrow

Wang

et al. 2006

130

The process of oocyte maturation, which impacts ovulation and fertilization, is complex and requires an integration of the endocrine, paracrine, juxtacrine, and autocrine signaling pathways. This process involves an intimate interaction between the oocyte and encircling cumulus cells within a follicle, a unique venue for somatic and germ cell communication. Cumulus cell expansion and resumption of meiosis with germinal vesicle breakdown are major events in oocyte maturation. Cyclooxygenase-2 (COX-2)-derived prostaglandin E 2 (PGE 2 ) is a known critical mediator of oocyte maturation, but the diverse function of this lipid mediator in oocyte maturation, ovulation, and fertilization has not been fully appreciated. We show here that gonadotropins in coordination with PGE 2 signaling via its cell surface G-protein-coupled EP2 and EP4 receptor subtypes direct cumulus cell expansion and survival and oocyte meiotic maturation by differentially impacting cAMPdependent protein kinase, MAPK, NF-B, and phosphatidylinositol 3-kinase/Akt pathways. This study is unique in the sense that it provides evidence for new site-and event-specific involvement of these signaling pathways under the influence of COX-2-derived PGE 2 during the critical stages of this somatic-germ cell interaction, an absolute requirement for oocyte maturation. Prostaglandins (PGs)4 are involved in various female reproductive functions, including ovulation, fertilization, and implantation (1, 2). The cyclooxygenase (COX)

“…This expansion of the ovulatory follicle is caused by rapid HA synthesis, resulting in the formation of an HA-rich extracellular matrix. Studies in knock-out mice have shown that three genes, encoding TSG-6, pentraxin 3 (PTX3), and bikunin, one of the polypeptide chains of I␣I, are essential for the structural integrity of the cumulus cell-oocyte complex during ovulation and that the disruption of any one of these genes impairs female fertility (1,11,(52)(53)(54). It is assumed that the stability of the cumulus cell-oocyte complex matrix is achieved by crosslinking of HA.…”

Section: Discussionmentioning

confidence: 99%

TSG-6 Protein Binding to Glycosaminoglycans

Wisniewski

Snitkin

Mindrescu

et al. 2005

TSG-6 protein, up-regulated in inflammatory lesions and in the ovary during ovulation, shows anti-inflammatory activity and plays an essential role in female fertility. Studies in murine models of acute inflammation and experimental arthritis demonstrated that TSG-6 has a strong anti-inflammatory and chondroprotective effect. TSG-6 protein is composed of the N-terminal link module that binds hyaluronan and a C-terminal CUB domain, present in a variety of proteins. Interactions between the isolated link module and hyaluronan have been studied extensively, but little is known about the binding of full-length TSG-6 protein to hyaluronan and other glycosaminoglycans. We show that TSG-6 protein and hyaluronan, in a temperature-dependent fashion, form a stable complex that is resistant to dissociating agents. The formation of such stable complexes may underlie the activities of TSG-6 protein in inflammation and fertility, e.g. the TSG-6-dependent cross-linking of hyaluronan in the cumulus cell-oocyte complex during ovulation. Because adhesion to hyaluronan is involved in cell trafficking in inflammatory processes, we also studied the effect of TSG-6 on cell adhesion. TSG-6 binding to immobilized hyaluronan did not interfere with subsequent adhesion of lymphoid cells. In addition to immobilized hyaluronan, full-length TSG-6 also binds free hyaluronan and all chondroitin sulfate isoforms under physiological conditions. These interactions may contribute to the localization of TSG-6 in cartilage and to its chondroprotective and anti-inflammatory effects in models of arthritis.