Menstrual cycle-specific inhibition of the proliferation of endometrial stromal cells by interleukin 6 and its soluble receptor

Endometrial cell‑derived exosomes facilitate the development of adenomyosis via the IL‑6/JAK2/STAT3 pathway

Interleukin (IL)-6 upregulation is involved in the pathogenesis of adenomyosis, but the underlying mechanism remains to be elucidated. Exosomes mediate intercellular communication, therefore the present study investigated whether endometrial cell-derived exosomes mediated the crosstalk between the endometrium and the myometrium via IL-6 signaling. Primary adenomyotic myometrial (AM) cells and eutopic endometrial cells were isolated from patients with adenomyosis. Exosomes were obtained from endometrial cells and incubated with AM cells in the presence or absence of tocilizumab (an IL-6 inhibitor). MTT, flow cytometry and wound-healing assays were performed to examine AM cell proliferation, apoptosis, cell cycle distribution and migration. Western blotting and reverse transcription-quantitative PCR were conducted to determine the expression of the IL-6/Janus kinase 2 (JAK2)/STAT3 pathway proteins. Incubation with endometrial cell exosomes suppressed cell apoptosis of AM cells compared with controls, accompanied by increases in IL-6 production and JAK2/STAT3 phosphorylation. Endometrial cell exosomes promoted cell proliferation, increased the percentage of S-phase cells and enhanced the migration of AM cells. These effects were completely reversed by tocilizumab, along with substantial decreases in IL-6 production and JAK2/STAT3 phosphorylation. Endometrial cell-derived exosomes promote cell proliferation, migration and cell cycle transition of AM cells through IL-6/JAK2/STAT3 activation, facilitating the development of adenomyosis by mediating the crosstalk between the endometrium and the myometrium, and IL-6 targeted therapy could be a complementary approach against adenomyosis.

Dietary cadmium chloride impairs shell biomineralization by disrupting the metabolism of the eggshell gland in laying hens

In this study, we identified cadmium (Cd) as a potential endocrine disruptor that impairs laying performance, egg quality, and eggshell deposition and induces oxidative stress and inflammation in the eggshell glands of laying hens. A total of 480 38-wk-old laying hens were randomly assigned into 5 groups that were fed a basal diet (control) or a basal diet supplemented with Cd (provided as CdCl2·2.5 H2O) at 7.5, 15, 30, and 60 mg Cd per kg feed for 9 wk. The results showed that, when compared with the control group, a low dose of dietary Cd (7.5 mg/kg) had positive effects on egg quality by improving albumen height, Haugh unit, yolk color, and shell thickness at the third or ninth week. However, with the increase in the dose and duration of Cd exposure, the laying performance, egg quality, and activities of eggshell gland antioxidant enzymes (catalase [CAT], glutathione peroxide [GSH-Px]), and ATPase (Na+/K+-ATPase, Ca2+-ATPase, and Mg2+-ATPase) deteriorated, and the activity of total nitric oxide synthase (T-NOS) and the level of malondialdehyde (MDA) increased significantly (P < 0.05). The histopathology and real-time quantitative PCR results showed that Cd induced endometrial epithelial cell proliferation accompanied by upregulation of the mRNA levels of progesterone receptor (PgR) and epidermal growth factor receptor (EGFR), downregulation of the mRNA levels of estrogen receptor α (ERα) and interleukin 6 (IL6), and inflammation of the eggshell gland accompanied by significantly increased expression of complement C3 and pro-inflammatory cytokine tumor necrosis factor α (TNFα) (P < 0.05). In addition, the ultrastructure of the eggshell showed that dietary supplementation with 7.5 mg/kg Cd increased the palisade layer and total thickness of the shell, but with the increase in dietary Cd supplementation (30 and 60 mg/kg) the thickness of the palisade layer and mammillary layer decreased significantly (P < 0.05), and the outer surface of the eggshell became rougher. Correspondingly, the expression of calbindin 1 (CALB1), ovocalyxin-32 (OCX-32), ovocalyxin-36 (OCX-36), osteopontin (SPP1), and ovocledidin-17 (OC-17) decreased significantly (P < 0.05) with increasing dietary Cd supplementation. Conclusively, the present study demonstrates that dietary supplementation with Cd negatively affects laying performance, egg quality, and eggshell deposition by disturbing the metabolism of eggshell glands in laying hens but has a positive effect on egg quality at low doses.

Molecular and Cellular Pathogenesis of Endometriosis

BACKGROUND

A substantial body of studies supports the view that molecular and cellular features of endometriotic lesions differ from those of eutopic endometrium. Apart from that, evidence exists that the eutopic endometrium from pa-tients with endometriosis differs from that of females without endometriosis.

OBJECTIVE

Aberrant expression profiles include a number of non-steroid signaling pathways that exert their putative influ-ence on the pathogenesis of endometriosis at least in part via crosstalk(s) with estrogen-mediated mechanisms. A rational to focus research on non-steroid signal pathways is that they might be remunerative targets for the development and selection of novel therapeutics to treat endometriosis possibly without affecting estrogen levels.

RESULTS AND CONCLUSION

In this article, we describe molecular and cellular features of endometriotic lesions and focus on the canonical WNT/β-signaling pathway, a key regulatory system in biology (including stem cell homeostasis) and often in pathophysiological conditions such as endometriosis. Recently emerged novel biological concepts in signal transduction and gene regulation like exosomes and microRNAs are discussed in their putative role in the pathogenesis of endometriosis.

Altered apoptosis and proliferation in endometrial stromal cells of women with adenomyosis

BACKGROUND

The eutopic endometrium in a woman suffering from adenomyosis is known to be biologically different from that of healthy women. The aim of this study was to examine the apoptosis and proliferation of eutopic endometrium from women with adenomyosis.

METHODS

We enrolled 23 women with adenomyosis (study group) and 21 without (control group). Eutopic endometrium was obtained and separated into single endometrial stromal cells (ESCs). ESCs were treated in vitro with hydrogen peroxide (H(2)O(2)) to examine their apoptosis using a fluorescence-activated cell sorter. Cells were also treated with estradiol (E(2)), medroxyprogesterone acetate, interleukin (IL)-6, lipopolysaccharide and interferon-gamma (IFN-gamma) to test their proliferation using a non-radioactive cell proliferation assay.

RESULTS

The percentage of annexin V ( + )/7-amino-actinomycin D ( + ) ESCs was much lower in women with adenomyosis after 24 h culture with and without H(2)O(2) treatment when compared with the control group. ESCs of adenomyosis proliferated more rapidly than those of the control group, whether they were cultured alone or were treated with E(2), MPA, IL-6 or IFN-gamma. The immunocytochemical Ki-67 labelling index was much more prominent in adenomyotic ESCs than that of the control group (7.7% versus 1.1%, P < 0.001).

CONCLUSIONS

Altered apoptosis and proliferation of eutopic endometrium possibly elucidate some aspects of the pathophysiology of adenomyosis. A high Ki-67 labelling index in immunocytochemistry might be a potential indicator in predicting the occurrence of adenomyosis.

Estradiol and its membrane-impermeable conjugate estradiol-BSA inhibit tamoxifen-stimulated prolactin secretion in incubated rat pituitaries

In the absence of estrogen (E), the selective E receptor modulator tamoxifen (TX) has two agonist effects in the rat pituitary: induction of progesterone receptor (PR)-dependent GnRH self-priming in the gonadotrope, and stimulation of prolactin (PRL) secretion in the lactotrope. TX-induced gonadotropin (GnRH) self-priming is absent when 10(-8) M estradiol-17beta (E2) is added to the incubation medium of pituitaries from TX-treated rats. The present experiments investigated whether PR-independent PRL release into the incubation medium of pituitaries from TX-treated ovariectomized (OVX) rats was affected by E2, and the effect of different ER ligands (ICI182780, TX, estradiol-17alpha, E2 -BSA) on TX-stimulated PRL secretion. Moreover, the effect of E2 on TRH-stimulated PRL secretion in pituitaries collected from estradiol benzoate- and TX-treated OVX rats was studied. It was found that: i) incubation with E2 supressed the PRL releasing effect of injected TX; ii) whereas coincubation with the pure anti-E type II ICI182780 antagonized the inhibitory effect of E2, coincubation with the anti-E type I TX did not; iii) estradiol-17alpha lacked inhibitory action, whereas a dose-dependent inhibitory effect of both E2 and E2 -BSA was noticed; and iv) TRH stimulatory effect on PRL release in pituitaries from TX-treated rats was blocked by addition of E2 to the medium. Taken together, these data argue in favor of the presence of specific membrane recognition sites for E in the lactotrope involved in steroid-specific E2 inhibition of TX-stimulated PRL secretion.

Is Endometriosis Associated with Systemic Subclinical Inflammation?

Endometriosis is a pelvic inflammatory process with altered function of immune-related cells and increased number of activated macrophages in the peritoneal environment that secrete various local products, such as growth factors and cytokines. The elevation of cytokines and other factors in the peritoneal fluid is accompanied by the elevation of similar factors, such as CRP, SAA, TNF-alpha, MCP-1, IL-6, IL-8 and CCR1, in the peripheral blood of patients with endometriosis. CD44+ and CD14+ monocytes are significantly increased, while CD3+ T lymphocytes and CD20+ B lymphocytes show modest, but significant decrease in peripheral blood of women with endometriosis. This indicates that endometriosis could be viewed as a local disease with systemic subclinical manifestations. This review provides an overview of data on the changes of various factors in peripheral blood and their potential use as diagnostic tools in patients with endometriosis.

Immunology and Endometriosis

PROBLEM

Accumulating data suggests that aberrant immune responses during retrograde menstruation may be involved in the development of endometriosis.

METHOD OF STUDY

The role of immunology in the etiology of endometriosis is reviewed and summarized from the available literature.

RESULTS

Immunologic factors may affect a woman's susceptibility to implantation of exfoliated endometrial cells. Immune alterations include increased number and activation of peritoneal macrophages, decreased T cell reactivity and natural killer cell cytotoxicity, increased circulating antibodies, and changes in the cytokine network.

CONCLUSION

There is substantial evidence that immunologic factors play a role in the pathogenesis of endometriosis and endometriosis-associated infertility. Decreased natural killer cell cytotoxicity leads to an increased likelihood of implantation of endometriotic tissue. In addition, macrophages and a complex network of locally produced cytokines modulate the growth and inflammatory behavior of ectopic endometrial implants.

The role of cytokines in endometriosis

PROBLEM

To review the literature on the role of peritoneal cytokines in the pathogenesis and endometriosis-related infertility.

METHODS OF STUDY

A MEDLINE search was conducted by the key words of cytokine and endometriosis in the English publications, and references identified within the identified papers were also reviewed.

RESULTS

Several cytokines including interleukin (IL)-1, 6, 8, 10, tumor necrosis factor (TNF)-alpha, and vascular endothelial growth factor (VEGF) were reported to be increased in the peritoneal fluid (PF) of women with endometriosis. Those cytokines may be involved in macrophage activation, inflammatory change and enhanced angiogenesis. However, some cytokines were less expressed such as IL-2, and interferon (IFN)-gamma. They reflect the impaired T- and natural killer (NK)-cell function. Endometriotic implants produce some factors, e.g. matrix metalloproteinases (MMPs), Bcl-2, and affect their capacity to implant into the peritoneum.

CONCLUSION

Peritoneal cytokines, which are produced by mesothelial cells, leukocytes and ectopic endometrial cells, interwork locally and systemically in women with endometriosis. More studies about the specific role and interactions of these cytokines are needed to improve the understanding of endometriosis and to develop novel therapies.

The role of transsignalling via the agonistic soluble IL-6 receptor in human diseases

The activation of cells that do not express the membrane bound interleukin-6 6 receptor (IL-6R) by IL-6 and the soluble IL-6 receptor (sIL-6R) is termed transsignalling. Transsignalling may be an pathogenetic factor in human diseases as diverse as multiple myeloma (MM), Castleman's disease, prostate carcinoma, Crohn's disease, systemic sclerosis, Still's disease, osteoporosis and cardiovascular diseases. IL-6 and sIL-6R may directly or indirectly enhance their own production on endothelial or bone marrow stromal cells. Positive feedback autocrine loops thus created in affected organs may either cause or maintain disease progression. In autoimmune or vasculitic disease, the ability of the IL-6/sIL-6R complex to inhibit apoptosis of autoreactive T-cells may be central to the development of tissue specific autoimmunity. The anti-apoptotic effect of the IL-6/sIL-6R complex may be involved in tumour genesis and resistance to chemotherapy. Only in rare cases, where counterregulation has failed, there is a notable systemic effect of IL-6/sIL-6R. Appropriate animal models are necessary to establish the pathogenetic role of the IL-6/sIL-6R complex. A specific treatment option for diseases influenced by the sIL-6R could be based on gp130-Fc, a soluble gp130 (sgp130) linked to the Fc-fragment of IgG1. gp130-Fc has shown efficacy in vivo in animal models of Crohn's disease.

Was Sampson wrong?

OBJECTIVE

Sampson's theory of reflux menstruation suggests that endometriosis is one form of a condition known as an autotransplant. This study seeks to characterize autotransplants as they are described in the literature and to determine whether endometriosis resembles an autotransplant.

DESIGN

Literature review of published studies containing the following types of information: [1] characterization of the histologic features, immunohistochemistry, or structural function of autotransplants; and [2] comparisons of endometriosis with endometrium.

MAIN OUTCOME MEASURE(S)

Characteristics of multiple types of autotransplants were noted. Similarity or dissimilarity of endometriosis and endometrium was tabulated to judge qualitatively whether the bulk of the evidence supports the notion that endometriosis is an autotransplant.

RESULT(S)

Autotransplants remain very similar or identical to eutopic tissues of origin, regardless of the length of time following autotransplantation. Endometriosis differs in many profound and fundamental ways from eutopic endometrium, including clonality of origin, enzymatic activity, protein expression, and histologic and morphologic characteristics. A minority of studies has found similarities between endometriosis and eutopic endometrium.

CONCLUSION(S)

Endometriosis is dissimilar to eutopic endometrium and therefore lacks characteristics of an autotransplant. Sampson's theory of origin of endometriosis is not supported by the results of this study. Studies of experimental endometriosis that have not used menstrual endometrium may be misleading.

Menstrual cycle-specific inhibition of endometrial stromal cell proliferation by oncostatin M

We have investigated the possible roles of oncostatin M (OSM), which is a member of the interleukin-6 family of cytokines, in endometrial and endometriotic stromal cell growth. Endometrial and endometriotic stromal cells were collected from the uterus or ovarian chocolate cysts. We observed the expression of mRNA transcripts for OSM, OSM receptor subunit beta, leukaemia inhibitory factor receptor subunit (LIFR), and glycoprotein 130 in endometrial and endometriotic stromal cells. We also examined the effects of OSM (0-50 ng/ml) and LIF (0-10 ng/ml) on endometrial and endometriotic stromal cell proliferation and evaluated the effects of OSM on endometrial stromal cell differentiation. The presence of 10-50 ng/ml OSM significantly suppressed endometrial stromal cell growth in secretory phase tissue but not in proliferative phase tissue. In contrast, stromal cells in endometriotic tissues were resistant to the inhibitory effects of OSM. Addition of LIF did not influence the growth of endometrial stromal cells. We also showed that 10 ng/ml OSM stimulated markers of differentiation causing increased prolactin secretion and cyclooxygenase-2 gene expression in endometrial stromal cells from the secretory phase. These results suggest that OSM may play a pivotal role in regulating the growth and differentiation of endometrial cells. Endometriotic cells may behave differently from normal endometrial cells in terms of the inhibitory response to OSM.

Role of cytokines in endometriosis

OBJECTIVE

To review the literature on the role of cytokines in the pathogenesis of endometriosis and endometriosis-associated infertility.

DESIGN

Pertinent studies were identified by a computer search of MEDLINE. References of selected articles were hand-searched for additional citations.

RESULT(S)

Recent studies suggest that the peritoneal fluid of women with endometriosis contains an increased number of activated macrophages that secrete various local products, such as growth factors and cytokines. Levels of several cytokines were reported to be elevated in the peritoneal fluid of women with endometriosis. Because the peritoneal environment may be controlled by locally regulated factors, cytokines are believed to play a role in the development and progression of endometriosis and endometriosis-associated infertility. A possible pathogenic mechanism links cytokines with endometriosis.

CONCLUSION(S)

Cytokines, which are produced by many cell types including endometriotic tissues, play diverse roles in the pathogenesis of endometriosis and endometriosis-associated infertility. More studies about the specific role of these cells and soluble factors are needed to improve understanding of endometriosis and to develop novel therapies.

The genetic basis of endometriosis

Family studies have long suggested a role for genetic factors in the aetiology of endometriosis. The influence of genes on disease development has mainly been researched independently of environmental factors, yet their interaction must play an important role. Greater exposure to retrograde menstruation and oestrogen is likely to increase the risk of endometriosis; toxic compounds such as dioxin may increase the risk, although the only direct evidence has come from primate studies. Previous association studies implicated GALT (a gene involved in galactose metabolism), and GSTM1 and NAT2 (genes encoding for the detoxification enzymes) as possible disease susceptibility genes. Recent findings have added to the evidence for the involvement of GSTM1 and NAT2, but have cast doubt on the role of GALT. However, the design of many genetic and epidemiological studies has been inadequate with respect to sample size, consistency in phenotype definition, and the choice of control populations. These features are likely to influence results, and could partly explain the lack of consistency in the findings. Future studies should use a consistent disease definition and be of appropriate epidemiological design.

Expression of the cyclin-dependent kinase inhibitor p27Kip1 in eutopic endometrium and peritoneal endometriosis

OBJECTIVE

This study was undertaken to evaluate the immunohistochemical expression of the cell cycle inhibitor p27Kip1 and proliferation marker Ki67 in peritoneal endometriosis and eutopic endometrium.

DESIGN

Prospective study.

SETTING

University hospital.

PATIENT(S)

Thirty-one patients with peritoneal endometriosis.

INTERVENTION(S)

During laparoscopy, 25 samples of predominantly red peritoneal lesions and 27 samples of predominantly black peritoneal lesions were collected from 31 patients with endometriosis. Eutopic endometrium from 25 patients with endometriosis was collected by curettage during laparoscopy or just after surgery.

MAIN OUTCOME MEASURE(S)

The percentage of glandular and stromal cells exhibiting positive staining for p27Kip1 and Ki67 (labeling index, LI) was determined.

RESULT(S)

The LI of stromal cells in red peritoneal lesions for both p27Kip1 and Ki67 was similar to that of proliferative eutopic endometrium. Although the LI of glandular epithelial cells for Ki67 in red lesions was comparable to that of proliferative eutopic endometrium, the LI for p27Kip1 was significantly higher. Furthermore, we detected a significantly higher LI of glandular epithelial and stromal cells for p27Kip1 in black lesions compared with red lesions.

CONCLUSION(S)

Our results suggest that expression of the cyclin kinase inhibitor p27Kip1 is involved in the natural history and progression of peritoneal endometriosis.

Altered gene expression and secretion of interleukin-6 in stromal cells derived from endometriotic tissues

OBJECTIVE

To compare the expression of interleukin-6 (IL-6) in endometrial and endometriotic cells.

DESIGN

Prospective study.

SETTING

Department of Obstetrics and Gynecology, Tottori University Hospital, Yonago, Japan.

PATIENT(S)

Twenty patients who underwent either hysterectomy or laparoscopic surgery.

INTERVENTION(S)

Endometrial and endometriotic stromal cells were obtained from normal endometrium and from chocolate cyst linings of the ovary. Peritoneal macrophages were isolated from peritoneal fluids. Cells were cultured in the presence or absence of tumor necrosis factor-alpha.

MAIN OUTCOME MEASURE(S)

Gene expression of IL-6 was examined by Northern blot analysis. Interleukin-6 protein production was examined by immunocytochemical staining and ELISA.

RESULT(S)

A single IL-6 messenger RNA band of approximately 1.3 kilobases was detected in endometriotic stromal cells. Tumor necrosis factor-alpha increased the expression of IL-6 messenger RNA in endometriotic cells in a dose-dependent manner. In endometrial stromal cells, IL-6 messenger RNA signals were much weaker. Endometriotic stromal cells produced significantly larger amounts of IL-6 compared with endometrial stromal cells under basal conditions and after stimulation with tumor necrosis factor-alpha. Interleukin-6 protein was detected in cells isolated from endometriotic tissues by immunocytochemical staining. Interleukin-6 production by cultured macrophages from patients with endometriosis and endometriotic stromal cells was comparable.

CONCLUSION(S)

Altered gene expression and protein secretion of IL-6 in patients with endometriosis may contribute to the pathogenesis of the disease and/or to endometriosis-associated infertility.