Gelatinases, endonuclease and Vascular Endothelial Growth Factor during development and regression of swine luteal tissue

The expression and localization of selected matrix metalloproteinases (MMP-2, -7 and -9) and their tissue inhibitors (TIMP-2 and -3) in follicular cysts of sows

Matrix metalloproteinases (MMPs) are a family of enzymes that degrade extracellular matrix (ECM) molecules, playing a vital role in tissue remodeling under physiological and pathological conditions. Their expression and/or activity are regulated by specific tissue inhibitors of MMPs named TIMPs. Recently, an imbalance in the MMP/TIMP system has been found in human and bovine ovarian cysts, but its role in porcine cyst pathogenesis is unknown. This study examined mRNA expression, protein abundance and localization for selected members of the MMP/TIMP system in follicular cysts of sows. Based on histological analysis, we have assessed follicular (FC) and follicular lutein (FLC) cysts with preovulatory follicles (PF) used as a control. Regarding the pattern of MMP expression, increased MMP2, MMP7 and MMP9 mRNA levels were observed in FLC. Furthermore, both pro- and active forms of MMP-2 and MMP-9 proteins were more abundant in FLC. In FC, the abundance of latent and active forms of MMP-9 and the active form of MMP-2 were greater when compared with PF. In relation to TIMPs, TIMP-2 mRNA and protein expression were increased in FLC, whereas TIMP-3 was up-regulated in both FC and FLC only at the protein level. Using immunofluorescence, MMP-2, MMP-7, TIMP-2 and TIMP-3 were detected in granulosa and theca compartments of FC and within the entire luteinized wall of FLC. Notably, MMP-9 occurred weakly in the granulosa layer of FC, but abundantly in the theca compartment of FC and in the luteinized FLC. Taken together, our findings indicate altered expression of the MMP/TIMP system, suggestive of increased ECM degradation, in sow follicular cysts. These components may be involved in the pathogenesis of porcine ovarian cysts through the ECM remodeling.

Effects of adrenocorticotrophic hormone on the expression of matrix metalloproteinases and their inhibitors in the bovine ovary

Cattle undergo numerous environmental and management stressors that reduce fertility and affect ovulation. The extracellular matrix of the follicle wall can be altered by matrix metalloproteinases (MMPs), the activities of which are regulated by interleukins and tissue-specific inhibitors of metalloproteinases (TIMPs), especially during ovulation. The aims of the present study were to: (1) evaluate changes in the hormone milieu, the localisation and activity of MMP2 and MMP9 and the localisation of MMP14, TIMP1 and TIMP2 in response to adrenocorticotrophic hormone (ACTH) during the preovulatory period in cows; and (2) determine the direct effects of ACTH on the mRNA expression of MMP2 and MMP9 in the cultured follicle wall of bovine ovaries obtained from an abattoir. 100IU ACTH was administered during pro-oestrus every 12h until ovariectomy, which was performed before ovulation. Cortisol concentrations in the plasma and follicular fluid (FF) of preovulatory follicles were higher in ACTH-treated than control cows. Progesterone presented subluteal concentrations in plasma of ACTH-treated cows (P<0.05). MMP2 immunostaining and activity in ovaries were higher in ACTH-treated than control cows (P<0.05), whereas MMP9 immunostaining was similar between the two groups. However, unlike in control cows, MMP9 activity was absent in the FF of ACTH-treated cows. These results suggest that the administration of ACTH during the preovulatory period in cows could cause changes that culminate in modifications in the content and activation of MMPs and TIMPs in the ovary, which could interfere with the ovulation process.

Uncovering the Physiological Mechanisms Underlying the Roe Deer (Capreolus capreolus) Testicular Cycle: Analyses of Gelatinases and VEGF Patterns and Correlation with Testes Weight and Testosterone

Simple Summary

The roe deer (Capreolus capreolus) is a wild, small ruminant common in Europe and Asia with a peculiar reproductive cycle. The adult male shows a complete suspension of spermatozoa production during the winter that start again in spring with the peak of sexual activity in summer (July–August). The physiological mechanism underlying such a cycle is yet to be clarified. The work aimed at the analysis of some molecules, like gelatinases (MMP) and vascular growth factor, physiologically involved in tissue remodeling, in roe deer samples collected before (June–July) and after (August–September) the rutting period. Samples were provided by hunters of the Bologna Apennines area (Italy) according to the regional hunting plan. The result showed a post-rut reduction of testicular weight and testosterone, indicative of testes involution, correlated with an increase in pro-MMP2, the latent gelatinase capable of sustaining spermatogenesis once activated. It can be assumed that gelatinases are involved in the testicular cycle and start accumulating after the rutting period to be then activated in preparation of the next reproductive season inducing spermatozoa development and migration. Future studies on this pathway during all seasonal testicular cycles will provide more information about the interesting reproductive physiology of roe deer.

Abstract

The roe deer (Capreolus capreolus) represents a spontaneous model of testicular inactivation: During winter, bucks show a suspension of spermatogenesis that starts again in spring and peaks during the breeding season (July–August). The underlying mechanisms to the regulation of the cyclic testicular changes are still not fully clear but seem to be imputable to the spermatogenic cell line since other testicular cell populations remain stable without apoptotic phenomena. The aim of the study was to investigate apoptosis, gelatinases (MMP2 and 9), their inhibiting factors (TIMP 1-2), and two isoforms of vascular endothelial growth factor (VEGF121 and 165) with its receptors (VEGFR1-2) in testes collected during pre- and post-rut periods, and to correlate them with testicular weight (TW) and testosterone (TEST). Testes from 18 adult sexually mature bucks were collected in Bologna Apennines (Italy). Samples were weighed and parenchyma collected. Radioimmunoassay, real-time PCR, and zymography were performed. The results showed a post-rut decrease in TW and TEST and an increase in proMMP2, also highlighting a correlation between the gelatinases and the testicular functionality. The VEGF pattern did not show modifications nor correlation with TW and TEST. Overall, gelatinases and their inhibitors, described herein for the first time in roe deer testes, seem to play an important role in the testicular cycle.

Polymorphism, genetic effect and association with egg production traits of chicken matrix metalloproteinases 9 promoter

Matrix metalloproteinases (MMP) are key enzymes involved in cell and tissue remodeling during ovarian follicle development and ovulation. The control of MMP9 transcription in ovarian follicles occurs through a core promoter region (−2,400 to −1,700 bp). The aim of this study was to screen genetic variations in the core promoter region and examine MMP9 transcription regulation and reproduction performance. A single cytosine deletion/insertion polymorphism was found at −1954 C⁺/C⁻. Genetic association analysis indicated significant correlation between the deletion genotype (C⁻) with total egg numbers at 28 weeks (p = 0.031). Furthermore, luciferase-reporter assay showed the deletion genotype (C⁻) had significantly lower promoter activity than the insertion genotype (C⁺) in primary granulosa cells (p<0.01). Therefore, the identified polymorphism could be used for marker-assisted selection to improve chicken laying performance.

Expression and regulation of MMP1, MMP3, and MMP9 in the chicken ovary in response to gonadotropins, sex hormones, and TGFB1

Matrix metalloproteinases (MMPs) are a specific class of proteolytic enzymes that play critical roles in follicular development and luteinization in mammals. However, the role of MMPs in avian ovary remains largely unknown. We found that three MMP genes (MMP1, MMP3, and MMP9) were significantly up-regulated in 23-wk-old (laying phase) chicken ovaries compared with 6-wk-old ovaries (prepubertal phase). In reproductively active chicken ovary, MMP1 expression (both mRNA and protein) remained low in prehierarchical and preovulatory follicles but increased in postovulatory follicles (POFs). Both MMP3 and MMP9 expression levels increased during follicular maturation. MMP3 reached maximal expression in the first largest follicle (F1), while MMP9 levels continued to rise in POF1 and POF2 after ovulation. Immunohistochemistry, Western blot analysis, and zymography experiments indicated that MMP1, MMP3, and MMP9 were synthesized and secreted by granulosa cells of different follicles in the chicken ovary. The mRNA expression of MMP1 and MMP3 in the granulosa cells was stimulated by follicle-stimulating hormone, luteinizing hormone, progesterone, and estrogen but not by transforming growth factor beta 1 (TGFB1). However, the mRNA of MMP9 was induced by TGFB1 but not follicle-stimulating hormone, luteinizing hormone, progesterone, or estrogen. Luciferase reporter and mutagenesis analysis indicated the AP1 and NFkappaB elements located in the promoter region from -1700 to -2400 bp were critical for both basal and TGFB1-induced MMP9 transcription. These data provide the first spatial-temporal expression analysis of MMP system in the chicken ovary.

Development of a vessel organ culture system: characterisation of the method and implications for the reduction of animal experiments

In the field of cardiovascular research, the pig is considered to be an excellent animal model of human diseases. It is well-known that primary cultures of endothelial cells (ECs) are a powerful tool for the study of vascular physiology and pathology, and, according to the principles of the Three Rs, their use results in a substantial reduction in the numbers of experimental animals required. However, a limitation of EC culture is that the cells are not in their physiological context. Here, we describe and characterise a method for the culture of porcine vessels that overcomes the limitation of EC cultures, with the advantage of reducing the number of animals used for research purposes. The organ cultures were set-up by using an aortic cylinder obtained from the arteries of control pigs sacrificed for other experimental purposes. In order to characterise the method, vascular endothelial growth factor (VEGF) secretion, matrix metalloproteinase (MMP) activation and the vessel's structural features were evaluated during organ culture. These analyses confirm that the culture of aortic cylinder lumen, in a medium specific for ECs, results in a stable system in terms of VEGF and MMP secretion. The ECs do not undergo cell division during the organ culture, which is also the case in vivo, if no stimulation occurs. Overall, we show that this novel system closely resembles the in vivo context. Importantly, porcine aortas can be collected from either veterinary surgeries or slaughterhouses, without having to sacrifice animals specifically for the purposes of this type of research.

Transforming growth factor Beta 1 stimulates profibrotic activities of luteal fibroblasts in cows

Luteolysis is characterized by angioregression, luteal cell apoptosis, and remodeling of the extracellular matrix characterized by deposition of collagen 1. Transforming growth factor beta 1 (TGFB1) is a potent mediator of wound healing and fibrotic processes through stimulation of the synthesis of extracellular matrix components. We hypothesized that TGFB1 stimulates profibrotic activities of luteal fibroblasts. We examined the actions of TGFB1 on luteal fibroblast proliferation, extracellular matrix production, floating gel contraction, and chemotaxis. Fibroblasts were isolated from the bovine corpus luteum. Western blot analysis showed that luteal fibroblasts expressed collagen 1 and prolyl 4-hydroxylase but did not express markers of endothelial or steroidogenic cells. Treatment of fibroblasts with TGFB1 stimulated the phosphorylation of SMAD2 and SMAD3. [³H]thymidine incorporation studies showed that TGFB1 caused concentration-dependent reductions in DNA synthesis in luteal fibroblasts and significantly (P < 0.05) reduced the proliferative effect of FGF2 and fetal calf serum. However, TGFB1 did not reduce the viability of luteal fibroblasts. Treatment of luteal fibroblasts with TGFB1 induced the expression of laminin, collagen 1, and matrix metalloproteinase 1 as determined by Western blot analysis and gelatin zymography of conditioned medium. TGFB1 increased the chemotaxis of luteal fibroblasts toward fibronectin in a transwell system. Furthermore, TGFB1 increased the fibroblast-mediated contraction of floating bovine collagen 1 gels. These results suggest that TGFB1 contributes to the structural regression of the corpus luteum by stimulating luteal fibroblasts to remodel and contract the extracellular matrix.

Vascular endothelial growth factor stimulates organ-specific host matrix metalloproteinase-9 expression and ovarian cancer invasion

Vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMP) regulate each other, contributing to tumor progression. We have previously reported that MMP9 induces the release of tumor VEGF, promoting ascites formation in human ovarian carcinoma xenografts. The aim of this study was to investigate whether tumor-derived VEGF regulated the expression of gelatinase by the stroma, influencing the invasive properties of ovarian tumors. Tumor variants derived from 1A9 human ovarian carcinoma, stably expressing VEGF(121) in the sense (1A9-VS-1) and antisense orientations (1A9-VAS-3), were used. In vivo, zymographic analysis of tumors from 1A9-VS-1 implanted in the peritoneal cavity of nude mice showed higher levels of gelatinases, particularly murine MMP9, indicating that VEGF stimulates host expression of the matrix-degrading enzyme. Murine MMP9 expression was also high in the ovaries of mice bearing 1A9-VS-1 tumors. The effect on host MMP9 activity was organ-specific. The levels of host pro-MMP9 in ovaries correlated with the plasma levels of tumor VEGF and with the selective invasion of the ovaries. Induction of host MMP9 expression in tumors and ovaries was independent of the site of tumor growth as it was seen in mice carrying both intraperitoneal and subcutaneous tumors. The anti-VEGF antibody bevacizumab (Avastin) inhibited MMP9 expression and tumor invasion in the ovaries of mice bearing 1A9-VS-1 tumors. These findings point to a complex cross-talk between VEGF and MMPs in the progression of ovarian tumor and suggest the possibility of using VEGF inhibitors to affect MMP-dependent tumor invasion.