Fibronectin concentrations correlate with ovarian follicular size and estradiol values in equine follicular fluid

Growth factor-loaded ovarian extracellular matrix hydrogels promote in vivo ovarian niche regeneration and enhance fertility in premature ovarian insufficiency preclinical models

Premature ovarian insufficiency (POI) means menopause before 40 years of age affecting about 1 % of women. Approaches based on cell therapy and the paracrine effects of stem cells or bioproducts such as platelet-rich plasma have been proposed, but concerns remain about undesired systemic effects, as well as the need to optimize delivery methods through bioengineering methods. This study explores the efficacy of decellularized bovine ovarian cortex extracellular matrix (OvaECM) hydrogels alone and as a growth factor (GF) carrier (OvaECM+GF) in a chemotherapy-induced POI murine model. In vitro assays showed a gradual release of GF from the OvaECM sustained for two weeks. Chemotherapy drastically reduced follicle numbers, but OvaECM+GF treatment restored pre-antral follicle development. Moreover, this treatment notably regenerated the ovarian microenvironment by increasing cell proliferation and microvessel density while reducing chemotherapy-induced apoptosis and fibrosis. Whole-ovary RNA sequencing and gene set enrichment analysis revealed an upregulation of regeneration-related genes and a downregulation of apoptotic pathways. The OvaECM+GF treatment also yielded significantly better outcomes following ovarian stimulation and in vitro fertilization. After two consecutive crossbreeding cycles, OvaECM+GF-treated mice showed normal reproductive function. This research showcases the biocompatibility and efficacy of OvaECM to reverse POI in mice, setting a foundation to explore innovative bioengineering-based POI therapies. STATEMENT OF SIGNIFICANCE: Premature ovarian insufficiency (POI) affects about 1 % of women worldwide, causing early menopause before 40 years old. Current treatments alleviate symptoms but do not restore ovarian function. This study explores an innovative approach using ovarian cortex extracellular matrix hydrogels to deliver growth factors into the murine ovarian niche and reverse POI. In vitro release kinetic assays demonstrated a gradual and sustained release of growth factors. In a POI-induced mouse model, intraovarian injections of the hydrogel encapsulating growth factors restored pre-antral follicle development, increased cell proliferation, reduced apoptosis and fibrosis, and improved ovarian response and in vitro fertilization outcomes. Long-term benefits included larger litter sizes. This innovative technique shows promise in regenerating the ovarian environment and improving reproductive outcomes.

Advances of xenogeneic ovarian extracellular matrix hydrogels for in vitro follicle development and oocyte maturation

Research aimed at preserving female fertility is increasingly using bioengineering techniques to develop new platforms capable of supporting ovarian cell function in vitro and in vivo. Natural hydrogels (alginate, collagen, and fibrin) have been the most exploited approaches; however they are biologically inert and/or biochemically simple. Thus, establishing a suitable biomimetic hydrogel from decellularized ovarian cortex (OC) extracellular matrix (OvaECM) could provide a complex native biomaterial for follicle development and oocyte maturation. The objectives of this work were (i) to establish an optimal protocol to decellularize and solubilize bovine OC, (ii) to characterize the histological, molecular, ultrastructural, and proteomic properties of the resulting tissue and hydrogel, and (iii) to assess its biocompatibility and adequacy for murine in vitro follicle growth (IVFG). Sodium dodecyl sulfate was identified as the best detergent to develop bovine OvaECM hydrogels. Hydrogels added into standard media or used as plate coatings were employed for IVFG and oocyte maturation. Follicle growth, survival, hormone production, and oocyte maturation and developmental competence were evaluated. OvaECM hydrogel-supplemented media best supported follicle survival, expansion, and hormone production, while the coatings provided more mature and competent oocytes. Overall, the findings support the xenogeneic use of OvaECM hydrogels for future human female reproductive bioengineering.

Follicular-fluid proteomics during equine follicle development

The complex composition of the follicular fluid (FF), the intimate proximity to the oocyte, and the continual changes in their composition have a major effect on folliculogenesis and oogenesis. To date, the profiling of FF proteomes during follicle selection, development, and ovulation has not been comprehensively investigated. Therefore, a shotgun proteomics approach and bioinformatics analyses were used to profile the proteomes of equine FF harvested in vivo from follicles at the following development stages: predeviation (18-20 mm), deviation (22-25 mm), postdeviation (26-29 mm), preovulatory (30-35 mm), and impending ovulation. A total of 294 proteins were detected in FF (FDR <1%), corresponding to 65 common proteins and 124, 142, 167, 132, and 142 proteins in the predeviation, deviation, postdeviation, preovulatory, and impending ovulation groups, respectively. The higher expression of properdin and several other proteins belonging to the complement system during the deviation time and ovulation suggested their contribution in the selection of the future dominant follicle and ovulation. Apolipoprotein A-1 and antithrombin-III appeared to be important throughout folliculogenesis. The "complement and coagulation cascades" was the major KEGG pathway across all stages of follicle development. The significant expression of several proteins belonging to the serine-type endopeptidase indicated their likely contribution to follicle and oocyte development. Our data provide an extensive description and functional analyses of the equine FF proteome during follicle selection, development, and ovulation. This information will help improve understanding of the ovarian function and ovulatory dysfunctions and might serve as a reference for future biomarker discovery for oocyte quality assessment.

The role of the extracellular matrix in ovarian follicle development

Regulation of ovarian follicle development depends on endocrine- and paracrine-acting hormones, the 3-dimensional architecture of the follicle, and the physical rigidity of the surrounding tissue. These 3 forces are integrated throughout the life cycle of the follicle to ensure appropriate hormone secretion, differentiation of the somatic cells, and maturation of the oocyte. The process of in-follicle maturation provides a new tool for understanding ovarian follicle development under the influence of these factors.

Distribution of extracellular matrix proteins type I collagen, type IV collagen, fibronectin, and laminin in mouse folliculogenesis

The extracellular matrix (ECM) plays a prominent role in ovarian function by participating in processes such as cell migration, proliferation, growth, and development. Although some of these signaling processes have been characterized in the mouse, the relative quantity and distribution of ECM proteins within developing follicles of the ovary have not been characterized. This study uses immunohistochemistry and real-time PCR to characterize the ECM components type I collagen, type IV collagen, fibronectin, and laminin in the mouse ovary according to follicle stage and cellular compartment. Collagen I was present throughout the ovary, with higher concentrations in the ovarian surface epithelium and follicular compartments. Collagen IV was abundant in the theca cell compartment with low-level expression in the stroma and granulosa cells. The distribution of collagen was consistent throughout follicle maturation. Fibronectin staining in the stroma and theca cell compartment increased throughout follicle development, while staining in the granulosa cell compartment decreased. Heavy staining was also observed in the follicular fluid of antral follicles. Laminin was localized primarily to the theca cell compartment, with a defined ring at the exterior of the follicular granulosa cells marking the basement membrane. Low levels of laminin were also apparent in the stroma and granulosa cell compartment. Taken together, the ECM content of the mouse ovary changes during follicular development and reveals a distinct spatial and temporal pattern. This understanding of ECM composition and distribution can be used in the basic studies of ECM function during follicle development, and could aid in the development of in vitro systems for follicle growth.

Distribution patterns of TGF-alpha, laminin and fibronectin and their relationship with folliculogenesis in rat ovary

Many growth factors are considered to be involved in regulatory functions in the ovary. Specific factors mediate local cell-cell interactions in relation to follicle development. As a result of the complexity of the estrous cycles in experimental models, it is not easy to determine the role of a growth factor such as transforming growth factor alpha (TGF-alpha) in the system. Moreover, little is known about possible interactions of TGF-alpha and laminin and fibronectin in basement membranes during estrous cycles in relation to follicle development. Therefore, the present study was designed to investigate distribution patterns of TGF-alpha, laminin and fibronectin and their possible roles during follicle maturation in normal rat ovary. Ovaries were obtained from 6 adult virgin female rats and fixed in buffered neutral formalin. TGF-alpha, laminin, and fibronectin distribution patterns were evaluated using 5-7-microm-thick serial sections using the immunoperoxidase method. It was found that TGF-alpha was predominantly localised in nuclei of oocytes. Varying amounts of TGF-alpha were found in granulosa cells and interstitial thecal cells which form follicles. In addition, laminin and fibronectin were found predominantly in vascular walls, outer layers of granulosa cells and basement membranes of cuboidal/columnar surface epithelium of rat ovary. Therefore, we suggest that TGF-alpha is involved in follicular maturation. Moreover, because laminin was found to be present in between parenchymal follicle cell layers, we suggest that they were attached to supportive stromal cells by fibronectin. As TGF-alpha is associated with follicles and their relationship with the extracellular matrix, TGF-alpha may also induce formation of basement membranes which contains laminin and fibronectin components.

Ovulatory surges of human CG prevent hormone-induced granulosa cell tumor formation leading to the identification of tumor-associated changes in the transcriptome

Granulosa cell tumors comprise approximately 10% of ovarian tumors and, although rare, are clinically important due to their potential for malignancy and recurrence. Although their morphological features have been carefully described, the global changes in gene expression associated with their formation remain undetermined. To initiate this characterization, we used a transgenic mouse model in which granulosa cell tumors occur with 100% penetrance in CF-1 mice that harbor a novel transgene encoding a chimeric LHbeta subunit. When this transgene is expressed in other strains of mice, including (C57BL/6 female symbol x CF-1 male symbol,Tg) F1 hybrids, luteomas develop even though levels of LH remain high. This dichotomous response permits a longitudinal comparison of global changes in transcriptomes uniquely associated with either granulosa cell tumors or luteomas. Herein we report numerous changes in the transcriptome, including a decrease in LH receptor mRNA and increases in several mRNAs that encode secreted proteins previously associated with granulosa cell tumors. Furthermore, we identified a constellation of mRNAs that encode proteins that may serve as new markers for this tumor phenotype. Additional experiments indicated that periodic treatment with human CG prevented formation of granulosa cell tumors in mice genetically predisposed to tumor development and, instead, led to the appearance of luteomas. More importantly, ovarian transcriptomes from the luteomas induced by ovulatory doses of human CG permitted refined confirmation of gene expression changes that were uniquely associated with either granulosa cell tumors in the permissive CF-1 genetic background or in luteomas in the F1 hybrids. Together, these dynamic changes in the ovarian transcriptome indict various signaling pathways potentially involved in mediating the actions of LH over time and, depending on genetic background, the formation of either a luteoma or a granulosa cell tumor.

Amounts of selected coagulation factors in pre- and post-mortem follicular fluid are similar and do not correlate with molecular mass

This study was designed to evaluate the amounts of coagulation factors and to determine whether the protein profile in pre-ovulatory ovarian follicular fluid aspirated from ovaries collected from mares at slaughter are representative of that in follicular fluid collected from live animals. The proteins evaluated included, (i) albumin, ceruloplasmin and fibronectin, (ii) the procoagulant plasma proteins, Factor V (FV), Factor VII (FVII), Factor X (FX) and prothrombin, and (iii) the anticoagulant plasma proteins, antithrombin and alpha2-macroglobulin. The amounts of the individual proteins were similar in both types of follicular fluid. There was no correlation between the activity of FV, FVII, FX or prothrombin in follicular fluid and their molecular size although a correlation was found for the other proteins. These results suggest that the procoagulant proteins in follicular fluid are not likely derived from plasma. The total protein content of follicular fluid samples collected from both sources was similar and the results determined with the Biuret, Lowry and Biorad methods were also not significantly different (P>0.05).

Human ovarian follicular fluid has functional systems for the generation and modulation of thrombin

OBJECTIVE

To determine whether prothrombin is present in follicular fluid and whether the enzymatic pathways for prothrombin activation are similar to those in plasma.

DESIGN

Follicular fluid samples collected at the time of oocyte harvest for an assisted reproductive technology procedure (ART) were analyzed for a panel of hemostatic proteins with use of a combination of functional, chromogenic, and Western ligand blot analysis.

SETTING

An ART clinic and an academic research laboratory.

PATIENT(S)

Women undergoing ART.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Determination of components of thrombin generation and thrombin modulatory systems using functional and antigenic assay procedures.

RESULT(S)

Both prothrombin and components of the prothrombinase enzyme complex, which includes factors V, VII, and X, are present in follicular fluid. Other hemostatic proteins, including factors VIII and IX and vonWillebrand factor, are absent. The direct activation of prothrombin to thrombin is similar in follicular fluid and plasma. Like plasma, inhibitors of both thrombin and thrombin generation, including antithrombin, protein C, and alpha2-macroglobulin, are present in follicular fluid.

CONCLUSION(S)

Only a select group of hemostatic plasma proteins are present in follicular fluid. There is no direct correlation between molecular size and concentration of individual proteins in follicular fluid. These results indicate that the proteins involved in the thrombin-generating and thrombin modulatory pathways may be derived from ovarian cells, suggesting that thrombin may have a role in folliculogenesis.

Possible mechanisms of mammalian immunocontraception

Ecological and conservation programs in ecosystems around the world have experienced varied success in population management. One of the greatest problems is that human expansion has led to the shrinking of wildlife habitat and, as a result, the overpopulation of many different species has occurred. The pressures exerted by the increased number of animals has caused environmental damage. The humane and practical control of these populations has solicited the scientific community to arrive at a safe, effective, and cost-efficient means of population control. Immunocontraception using zona pellucida antigens, specifically porcine zona pellucida (pZP), has become one of the most promising population control tools in the world today, with notable successes in horses and elephants. A conundrum has risen where pZP, a single vaccine, successfully induces an immunocontraceptive effect in multiple species of mammals. This review describes the most current data pertaining to the mammalian zona pellucida and immunocontraception, and from these studies, we suggest several potential mechanisms of immunocontraception.