Impact of oestradiol and progesterone on the glycosaminoglycans and their depolymerizing enzymes of the rat mammary gland

Hyaluronic acid and proliferation/cellular death amount in the female rats mammary gland after estroprogestative therapy

AIMS

To evaluate the concentration of hyaluronan acid and proliferation/cellular death in mammary gland of ovariectomized female rat after estroprogestative therapy.

MATERIALS AND METHODS

Forty ovariectomized female rats were divided into four groups with 10 animals/each: OG (vehicle); EG: (Estradiol, 7 days of treatment), PG (Progesterone acetate, 23 days of treatment), and EPG: (Estradiol, 7 days of treatment, and next Progesterone acetate, 23 days of treatment). Twenty-four hours after the last treatment, all animals were euthanized, the mammary gland removed, then, a fragment was immersed in acetone to quantifying of the hyaluronan acid biochemical method (ELISA-Like fluorometric assay), and a fragment fixed for 24 h in 10% formaldehyde in phosphate-buffered saline (PBS) processed for immunohistochemistry method for detection of the cell marker proliferation (Ki67) and cellular marker death by DNA fragmentation the TUNEL method.

RESULTS

The estradiol-treatment alone (EG) or associated with progesterone (EPG) affected the concentration of hyaluronan acid, increased cell proliferation, and decreased cell death compared to OG and PG (p < .05) in the mammary tissue.

CONCLUSIONS

Our results suggest that the excessive reduction of HA in mammary tissue, as occurred with progesterone treatment, can lead to a breakdown of the extracellular matrix. These changes may be indicative of mammary pathology such as the development of tumor.

The role of estrogen in intervertebral disc degeneration

Intervertebral disc degeneration (IVDD) is a main contributor to low back and radicular pain, which imposes heavy economic burdens on society. However, the etiology and mechanism of IVDD are complex and still not completely clear. In particular, the role of estrogen in IVDD has not received much attention in recent research, although estrogen plays a crucial role in the metabolic dysfunction of others musculoskeletal structures, such as bone, muscle, and tendon. In this review, we attempt to describe the role of estrogen in IVDD and to summarize the proposed mechanisms in vivo and in vitro, as well as, to outline several interesting questions in this field.

Concentration of sulfated glycosaminoglycans in the mammary tissue of female rats with the aging and about hormonal influence

It was to evaluate the concentration of sulfate glycosaminoglycans (GAG) in mammary tissue of the young and adult female rats and ovariectomized females rats after hormonal stimulation. For this purpose, 60 female rats were divided into six groups with 10 animals/each: nonovariectomized groups: G1 (5 months), and G2 (15 months) and ovariectomized groups: OG (vehicle); EG: (estradiol, 7 days of treatment), PG (progesterone acetate, 23 days of treatment) and EPG: (estradiol (7 days of treatment) and next progesterone acetate (23 days of treatment). Twenty-four hours after the last treatment, all animals were euthanized, the mammary tissue removed, processed for biochemical evaluation and quantification of the GAG. The comparison between groups showed that the concentration dermatan sulfate (DS) G1 was lower compared to G2, OG, EG (p < .05) and G2 was lower compared to OG (p < .05), and OG was higher compared to EG, GP, EPG (p < .05); and heparan sulfate (HS) G1 was higher compared to G2 (p < .05), and G2 was higher compared to OG, EP, PG and EPG (p < .05). These changes in the extracellular matrix might explain, at least in part, hormonal influence about sulfated glycosaminoglycans in response to physiological state/age, and in response to hormonal treatment in the mammary tissues.

Functional interactions between 17 β -estradiol and progesterone regulate autophagy during acini formation by bovine mammary epithelial cells in 3D cultures

Mammary gland epithelium forms a network of ducts and alveolar units under control of ovarian hormones: 17-beta-estradiol (E2) and progesterone (P4). Mammary epithelial cells (MECs) cultured on reconstituted basement membrane (rBM) form three-dimensional (3D) acini composed of polarized monolayers surrounding a lumen. Using the 3D culture of BME-UV1 bovine MECs we previously demonstrated that autophagy was induced in the centrally located cells of developing spheroids, and sex steroids increased this process. In the present study we showed that E2 and P4 enhanced the expression of ATG3, ATG5, and BECN1 genes during acini formation, and this effect was accelerated in the presence of both hormones together. The stimulatory action of E2 and P4 was also reflected by increased levels of Atg5, Atg3, and LC3-II proteins. Additionally, the activity of kinases involved in autophagy regulation, Akt, ERK, AMPK, and mTOR, was examined. E2 + P4 slightly increased the level of phosphorylated AMPK but diminished phosphorylated Akt and mTOR on day 9 of 3D culture. Thus, the synergistic actions of E2 and P4 accelerate the development of bovine mammary acini, which may be connected with stimulation of ATGs expression, as well as regulation of signaling pathways (PI3K/Akt/mTOR; AMPK/mTOR) involved in autophagy induction.

Regulation of the hyaluronan system in ovine endometrium by ovarian steroids

In this study, we investigated steroid regulation of the hyaluronan (HA) system in ovine endometrium including HA synthases (HAS), hyaluronidases, and HA receptor-CD44 using 30 adult Welsh Mountain ewes. Eight ewes were kept intact and synchronized to estrous (day 0). Intact ewes were killed on day 9 (luteal phase; LUT; n=5) and day 16 (follicular phase; FOL; n=3). The remaining ewes (n=22) were ovariectomized and then treated (i.m.) with vehicle (n=6) or progesterone (n=8) for 10 days, or estrogen and progesterone for 3 days followed by 7 days of progesterone alone (n=8). Estradiol and progesterone concentrations in plasma correlated with the stage of estrous or steroid treatment. Our results showed trends (P<0.1) and statistically significant effects (P<0.05, by t-test) indicating that LUT had lower HAS1 and HAS2 and higher HAS3 and CD44 mRNA expression compared with FOL. This was reflected in immunostaining of the corresponding HAS proteins. Similarly, in ovariectomized ewes, progesterone decreased HAS1 and HAS2 and increased HAS3 and CD44, whereas estradiol tended to increase HAS2 and decrease CD44. Sometimes, HAS mRNA expression did not follow the same trend observed in the intact animals or the protein expression. HA and its associated genes and receptors were regulated by the steroids. In conclusion, these results show that the level of HA production and the molecular weight of HA in the endometrium are regulated by ovarian steroids through differential expression of different HAS both at the gene and at the protein levels.

Progesterone--promoter or inhibitor of breast cancer

Based on the results of a French cohort of postmenopausal women, it has been claimed that micronized progesterone does not enhance breast cancer risk. The impact of reproductive factors on breast cancer risk and a high prevalence of occult breast carcinomas at the time of menopause suggest an involvement of endogenous progesterone in the development of breast cancer. High mammographic density in the luteal phase and during treatment with estrogen/progestogen combinations reflect a change in the composition of mammary stroma and an increased water accumulation in the extracellular matrix which is caused by hygroscopic hyaluronan-proteoglycan aggregates. Proteoglycans are also involved in the regulation of proliferation, migration, and differentiation of epithelial cells and angiogenesis, and may influence malignant transformation of breast cells and progression of tumors. Reports on a lack of effect of estrogen/progesterone therapy on breast cancer risk may be rooted in a selective prescription to overweight women and/or to the very low progesterone serum levels after oral administration owing to a strong inactivation rate. The contradictory results concerning the proliferative effect of progesterone may be associated with a different local metabolism in normal compared to malignant breast tissue. Similar to other progestogens, hormone replacement therapy with progesterone seems to promote the development of breast cancer, provided that the progesterone serum levels have reached the threshold for endometrial protection.

N-sulfation of heparan sulfate regulates early branching events in the developing mammary gland

Branching morphogenesis, a fundamental process in the development of epithelial organs (e.g. breast, kidney, lung, salivary gland, prostate, pancreas), is in part dependent on sulfation of heparan sulfate proteoglycans. Proper sulfation is mediated by biosynthetic enzymes, including exostosin-2 (Ext2), N-deacetylase/N-sulfotransferases and heparan sulfate O-sulfotransferases. Recent conditional knockouts indicate that whereas primary branching is dependent on heparan sulfate, other stages are dependent upon selective addition of N-sulfate and/or 2-O sulfation (Crawford, B .E., Garner, O. B., Bishop, J. R., Zhang, D. Y., Bush, K. T., Nigam, S. K., and Esko, J. D. (2010) PLoS One 5, e10691; Garner, O .B., Bush, K. T., Nigam, S .K., Yamaguchi, Y., Xu, D., Esko, J. D., and Nigam, S. K. (2011) Dev. Biol. 355, 394-403). Here, we analyzed the effect of deleting both Ndst2 and Ndst1. Whereas deletion of Ndst1 has no major effect on primary or secondary branching, deletion of Ndst2 appears to result in a mild increase in branching. When both genes were deleted, ductal growth was variably diminished (likely due to variable Cre-recombinase activity), but an overabundance of branched structures was evident irrespective of the extent of gland growth or postnatal age. "Hyperbranching" is an unusual phenotype. The effects on N-sulfation and growth factor binding were confirmed biochemically. The results indicate that N-sulfation or a factor requiring N-sulfation regulates primary and secondary branching events in the developing mammary gland. Together with previous work, the data indicate that different stages of ductal branching and lobuloalveolar formation are regulated by distinct sets of heparan sulfate biosynthetic enzymes in an appropriate growth factor context.

A multifunctional 3D co-culture system for studies of mammary tissue morphogenesis and stem cell biology

Studies on the stem cell niche and the efficacy of cancer therapeutics require complex multicellular structures and interactions between different cell types and extracellular matrix (ECM) in three dimensional (3D) space. We have engineered a 3D in vitro model of mammary gland that encompasses a defined, porous collagen/hyaluronic acid (HA) scaffold forming a physiologically relevant foundation for epithelial and adipocyte co-culture. Polarized ductal and acinar structures form within this scaffold recapitulating normal tissue morphology in the absence of reconstituted basement membrane (rBM) hydrogel. Furthermore, organoid developmental outcome can be controlled by the ratio of collagen to HA, with a higher HA concentration favouring acinar morphological development. Importantly, this culture system recapitulates the stem cell niche as primary mammary stem cells form complex organoids, emphasising the utility of this approach for developmental and tumorigenic studies using genetically altered animals or human biopsy material, and for screening cancer therapeutics for personalised medicine.

Stage-dependent regulation of mammary ductal branching by heparan sulfate and HGF-cMet signaling

Specific interactions of growth factors with heparan sulfate may function as "switches" to regulate stages of branching morphogenesis in developing mammalian organs, such as breast, lung, salivary gland and kidney, but the evidence derives mostly from studies of explanted tissues or cell culture (Shah et al., 2004). We recently provided in vivo evidence that inactivation of Ndst1, the predominant N-deacetylase/N-sulfotransferase gene essential for the formation of mature heparan sulfate, results in a highly specific defect in murine lobuloalveolar development (Crawford et al., 2010). Here, we demonstrate a highly penetrant dramatic defect in primary branching by mammary epithelial-specific inactivation of Ext1, a subunit of the copolymerase complex that catalyzes the formation of the heparan sulfate chain. In contrast to Ext1 deletion, inactivation of Hs2st (which encodes an enzyme required for 2-O-sulfation of uronic acids in heparan sulfate) did not inhibit ductal formation but displayed markedly decreased secondary and ductal side-branches as well as fewer bifurcated terminal end buds. Targeted conditional deletion of c-Met, the receptor for HGF, in mammary epithelial cells showed similar defects in secondary and ductal side-branching, but did not result in any apparent defect in bifurcation of terminal end buds. Although there is published evidence indicating a role for 2-O sulfation in HGF binding, primary epithelial cells isolated from Hs2st conditional deletions were able to activate Erk in the presence of HGF and there appeared to be only a slight reduction in HGF-mediated c-Met phosphorylation in these cells compared to control. Thus, both c-Met and Hs2st play important, but partly independent, roles in secondary and ductal side-branching. When considered together with previous studies of Ndst1-deficient glands, the data presented here raise the possibility of partially-independent regulation by heparan sulfate-dependent pathways of primary ductal branching, terminal end bud bifurcation, secondary branching, ductal side-branching and lobuloalveolar formation.

The expression of syndecan-1, syndecan-4 and decorin in healthy human breast tissue during the menstrual cycle

BACKGROUND

In order to unravel the interactions between the epithelium and the extra cellular matrix (ECM) in breast tissue progressing to cancer, it is necessary to understand the relevant interactions in healthy tissue under normal physiologic settings. Proteoglycans in the ECM play an important role in the signaling between the different tissue compartments. The proteoglycan decorin is abundant in the breast stroma. Decreased expression in breast cancer tissue is a sign of a poor tumor prognosis. The heparane sulphate proteoglycans syndecan-1 and syndecan-4 promote the integration of cellular adhesion and proliferation. The aim of this study was to investigate the gene expression and location of decorin, syndecan-1 and syndecan-4 in the healthy breast during the menstrual cycle.

METHODS

Tissue from healthy women undergoing breast reduction plastic surgery was examined using immunohistochemistry (n = 38) and Real-Time RT-PCR (n = 20). Both parous and nulliparous women were eligible and the mean age of the women was 34(+/- 10 years) with regular menstrual cycles (28 +/- 7 days). None of the women had used hormonal treatment the last three months. The women were randomized to needle biopsy two months before the operation in the follicular or luteal menstrual phase and for another biopsy at the operation in the opposite phase. Serum samples were obtained to characterize the menstrual phase. The Wilcoxon signed rank test and Mann Whitney test were used for statistical analyses.

RESULTS

By real time-RT-PCR the gene signal for all three proteoglycans; decorin (p = 0.02) and syndecan-1 (p = 0.03) and syndecan-4 (p = 0.02) was significantly lower among parous women in the luteal phase than in the follicular phase. Immunohistochemistry confirmed the identification of the proteins but no significant difference between menstrual phases was observed. Serum samples verified the menstrual phase.

CONCLUSIONS

Our study shows, for the first time in the healthy breast, a significantly lower expression of the genes for the three proteoglycans, decorin, syndecan-1 and syndecan-4 in the luteal phase during the menstrual cycle. These changes were registered under normal physiologic conditions. Since ECM molecules appear to be involved in tumor progression, these findings in the normal breast could constitute a base for further studies in women receiving hormonal therapy or those with breast cancer.

Effect of oral and transdermal hormone therapy on hyaluronic acid in women with and without a history of intrahepatic cholestasis of pregnancy

OBJECTIVE

Intrahepatic cholestasis of pregnancy predisposes women to liver disorders years after affected pregnancy. We compared the basal levels and responses of hyaluronic acid, a marker of liver fibrosis, and liver transaminases to postmenopausal hormone therapy in women with (n = 20) and without (n = 20) a history of intrahepatic cholestasis of pregnancy.

STUDY DESIGN

This was a randomized, double-blind, placebo-controlled, crossover trial.

RESULTS

Basal levels of hyaluronic acid were similar in both groups. Two weeks of oral estradiol 2.0 mg/day led to significant but similar (10.9% to 15.4%) rises in hyaluronic acid in both groups. Increasing the dose of oral estradiol to 4.0 mg/day resulted in normalization of the levels, whereas the addition of medroxyprogesterone acetate led to falls (11.0% to 10.7 %) in hyaluronic acid. Transdermal estradiol 50 microg led to a rise (3.2 %) in hyaluronic acid only in the control group. Other liver markers were normal at baseline and during hormone therapy.

CONCLUSION

Normal basal levels and/or normal responses of hyaluronic acid and other liver markers to hormone therapy in women with previous intrahepatic cholestasis suggest that this therapy does not predispose these women to liver diseases.

CD44 is highly expressed on milk neutrophils in bovine mastitis and plays a role in their adhesion to matrix and mammary epithelium

Mastitis, inflammation of the mammary gland, is a common and economically important disease in dairy animals. Mammary pathogenic organisms, such as Escherichia coli, invade the teat canal,milk ducts, and mammary alveolar space, replicate in mammary secretions, and elicit a local inflammatory response characterized by massive recruitment of blood polymorphonuclear neutrophil leukocytes (PMN) into the alveoli and milk ducts. CD44 is a trans-membrane glycoprotein previously shown to play a role in mediation and control of blood PMN recruitment in response to inflammatory signals. Here we show, for the first time, increased expression of CD44 on recruited milk PMN in bovine mastitis and the expression of a CD44 variant, CD44v10, on these PMN. Furthermore, we demonstrate that CD44 mediates specific adhesion of bovine blood PMN to hyaluronic acid and mammary epithelial cells. Our results suggest that in mastitis CD44 plays a role in recruiting blood PMN into the mammary glands, the exact nature of this role needs to be elucidated.

Evaluation of leukocyte arylsulphatase a, serum interleukin-6 and urinary heparan sulphate following tamoxifen therapy in breast cancer

Leukocyte arylsulphatase A (AS-A) was shown to be significantly high in newly-diagnosed breast cancer patients. Previous reports imply a connection between serum interleukin-6 (IL-6) and breast cancer, possibly through a modulation of enzymes involved in estrogen synthesis. Abnormal distribution of heparan sulphate proteoglycans (HSPGs) in malignant breast epithelial cells suggests that they play a key role in the regulation of cell growth. Estradiol is believed to be effective in modulating glycosaminoglycans (GAGs) and their depolymerizing enzymes. Therefore, in this study, attempts were made to evaluate the activity of leukocyte arylsulphatase A, serum interleukin-6, urinary GAGs and heparan sulphate (HS) in response to tamoxifen (TAM) therapy in mastectomised breast cancer patients. Thirty-four patients (aged 30-82 years) were administered TAM (20 mg twice daily). Blood and urine samples of each patient were collected three times (at the beginning, and in third and sixth month of TAM therapy), and biochemical parameters were measured. There was no difference between baseline leukocyte AS-A activity and that measured after three months. At the end of six months, enzyme activity was significantly higher than the former values (p=0.022), but within the reference intervals reported in the literature. Although this increase might imply a normalization, the duration of TAM therapy is not long enough to make a decision about either regression or aggravation of the disease. TAM did not have any effect on serum IL-6, urinary HS and GAG levels which may be due to insensitivity of these variables to TAM during the short period of therapy. Both urinary GAG and HS levels measured at sixth month exhibited a positive correlation with the baseline level of leukocyte AS-A (p=0.005 and 0.009, respectively), suggesting that positive responses to the drug might be seen in patients with low AS-A activity.

Intervertebral disc height in treated and untreated overweight post-menopausal women

BACKGROUND

The effect of the menopause and HRT on the intervertebral discs has not been investigated.

METHODS

One hundred women were recruited, comprising of 44 post-menopausal women on HRT, 33 untreated post-menopausal women and 23 pre-menopausal women. The height of the intervertebral discs between the 12th thoracic vertebra and the 3rd lumbar vertebra was measured by utilizing the bone densitometer height cursors.

RESULTS

The untreated menopausal group of women had the lowest total disc height (D1-D3: 1.95 0.31 cm). This was significantly lower than the pre-menopausal group D1-D3: 2.16 0.24 cm) and the hormone-treated group (2.2 0.26 cm) (P > 0.02). The 2nd intervertebral disc consistently maintained a significant difference between the untreated menopausal group (D2: 0.63 0.13) and the other two groups (pre-menopausal group (D2: 0.72 0.09 cm) and treated menopausal group (D2: 0.73 0.12 cm) (P > 0.02).

CONCLUSIONS

Estrogen-replete women appear to maintain higher intervertebral discs compared to untreated post-menopausal women. The estrogenic milieu may be relevant because of the significant impact it has on the hydrophilic glycosaminoglycans, the water content, collagen and elastin of the intervertebral discs. The maintenance of adequate disc height may allow the intervertebral discs to retain their discoid shape and viscoelastic function, containing vertical forces which may threaten spinal architecture leading to vertebral body compression fractures.

Proteoglycans: pericellular and cell surface multireceptors that integrate external stimuli in the mammary gland

Proteoglycans consist of a core protein and an associated glycosaminoglycan (GAG) chain of heparan sulfate, chondroitin sulfate, dermatan sulfate or keratan sulfate, which are attached to a serine residue. The core proteins of cell surface proteoglycans may be transmembrane, e.g., syndecan, or GPI-anchored, e.g., glypican. Many different cell surface and matrix proteoglycan core proteins are expressed in the mammary gland and in mammary cells in culture. The level of expression of these core proteins, the structure of their GAG chains, and their degradation are regulated by many of the effectors that control the development and function of the mammary gland. Regulatory proteins of the mammary gland that bind GAG include many growth factors and morphogens (fibroblast growth factors, hepatocyte growth factor/scatter factor, members of the midkine family, wnts), matrix proteins (collagen, fibronectin, and laminin), enzymes (lipoprotein lipase) and microbial surface proteins. Structural diversity within GAG chains ensures that each protein-GAG interaction is as specific as necessary and a number of sequences of saccharides that recognize individual proteins have been elucidated. The GAG-protein interactions serve to regulate the signal output of growth factor receptor tyrosine kinase and hence cell fate as well as the storage and diffusion of extracellular protein effectors. In addition, GAGs clearly coordinate stromal and epithelial development, and they are active participants in mediating cell-cell and cell-matrix interactions. Since a single proteoglycan, even if it carries a single GAG chain, can bind multiple proteins, proteoglycans are also likely to act as multireceptors which promote the integration of cellular signals.