Interleukin-1 receptor antagonist expression in epithelial cells of human endometrium

ABCB5+ Limbal Epithelial Stem Cells Inhibit Developmental but Promote Inflammatory (Lymph) Angiogenesis While Preventing Corneal Inflammation

The limbus, the vascularized junction between the cornea and conjunctiva, is thought to function as a barrier against corneal neovascularization. However, the exact mechanisms regulating this remain unknown. In this study, the limbal epithelial stem cell (LESC) marker ABCB5 was used to investigate the role of LESCs in corneal neovascularization. In an ABCB5KO model, a mild but significant increase of limbal lymphatic and blood vascular network complexity was observed in developing mice (4 weeks) but not in adult mice. Conversely, when using a cornea suture model, the WT animals exhibited a mild but significant increase in the number of lymphatic vessel sprouts compared to the ABCB5KO, suggesting a contextual anti-lymphangiogenic effect of ABCB5 on the limbal vasculature during development, but a pro-lymphangiogenic effect under inflammatory challenge in adulthood. In addition, conditioned media from ABCB5-positive cultured human limbal epithelial cells (ABCB5+) stimulated human blood and lymphatic endothelial cell proliferation and migration. Finally, a proteomic analysis demonstrated ABCB5+ cells have a pro(lymph)angiogenic as well as an anti-inflammatory profile. These data suggest a novel dual, context-dependent role of ABCB5+ LESCs, inhibiting developmental but promoting inflammatory (lymph)angiogenesis in adulthood and exerting anti-inflammatory effects. These findings are of high clinical relevance in relation to LESC therapy against blindness.

Serum IL-1RA levels increase from follicular to luteal phase of the ovarian cycle: A pilot study on human female immune responses

The immune responses exhibited by females are distinct from those of males. Females are known to generate, among others, higher levels of antibodies, greater interferon responses, and increased levels of inflammatory mediators in response to pathogens. Mounting evidence suggests that gonadal hormones play a key role in these differences. To better understand the effect of cycling hormones on the immune response, we sought to investigate the relationship between gonadal hormone fluctuations during the ovarian cycle and the levels of interleukin 1β and IL-1RA, both in circulation and in PBMCs in response to TLR4 stimulation, in healthy premenopausal females. To do this we measured the gonadal hormones 17β-estradiol, progesterone, and luteinizing hormone, and the cytokines IL-1β and IL-1RA in nine cycling females at several time points throughout one complete cycle. We evaluated 35 follicular, 17 ovulatory, and 44 luteal time points in our cohort and found a clear increase in serum levels of anti-inflammatory IL-1RA in the luteal phase, as compared to the follicular phase, and a positive correlation between both 17β-estradiol and progesterone and IL-RA. There was no difference in the serum levels of IL-1β and no difference in IL-1 β or IL-1RA produced in response to LPS by PBMCs isolated from different phases. Division of the cycle into sub-phases revealed an increase in the level of IL-1RA by ovulation that persisted through the luteal phase. These data suggest that significant changes in the immune response occur throughout the ovarian cycle in healthy females.

Interleukin 1 regulates its own receptors in human endometrial cells via distinct mechanisms

BACKGROUND

Interleukin 1 (IL1) plays an important role in the physiology of human endometrium and is recognized as a major and early embryonic signal. Tight control over the local endometrial action of this cytokine is critical for normal reproductive functions. The coordinated regulation of IL1 receptors types I and II (IL1R1 and IL1R2) and IL1 receptor antagonist (IL1RA) in endometrial cells may represent one of the principle mechanisms involved in the control of IL1 local effects. The objective of this study was to investigate the regulation of IL1Rs in human endometrial epithelial cells in response to IL1.

METHODS

Cultures of KLE endometrial epithelial cell line and primary human endometrial epithelial cells, immunofluorescent staining, enzyme-linked immunosorbent assay, western blotting, nuclear transcription (run-on) and real-time PCR were used to investigate the expression of IL1R1, IL1R2 and IL1RA.

RESULTS

Cells appeared to react to IL1 by up-regulating the expression of the signaling activating IL1R1 and to moderate in parallel IL1 effects by elevating the expression of the decoy inhibitory IL1R2 and the receptor antagonist IL1RA. Regulation of IL1R1 and IL1RA by IL1B involved gene transcription activation and that of IL1R2 involved mRNA stabilization.

CONCLUSION

Considering IL1's immunomodulatory, proangiogenic and tissue remodeling properties, and its role as an embryonic signal, modulation of endometrial cell responsiveness to IL1 via the concomitant regulation of its own activating and inhibitory receptors and receptor antagonist may represent an important regulatory mechanism of IL1-induced physiological changes occurring in the human endometrium during the normal menstrual cycle and embryo development.

Interleukin-1 system in the human fallopian tube-No spatial but a temporal regulation of mRNA and protein expression

The human fallopian tube provides the environment for the first 5 days of embryonic development in vivo. The IL-1 system is involved in human embryo implantation. This study aimed to investigate IL-1beta, IL-1ra and IL-1R tI expression within the length of the human fallopian tube on mRNA- and protein-level in samples from proliferative versus secretory phase, postmenopause (PMP) samples and samples from intra- (IUP) and extrauterine pregnancies (EUP) to examine possible spatial and hormonal induced changes (fimbrial, ampullary and isthmic tube segments). On mRNA-level, IL-1beta was expressed in all samples except in PMP. IL-1R tI could be detected in all samples whereas IL-1ra was only expressed in secretory phase and the IUP sample. Immunohistochemically we could detect IL-1beta and IL-1R t1 protein in all proliferative and secretory phase samples with maximum intensity in secretory phase samples whereas IL-1ra was expressed in secretory phase samples only. Overall no spatial but temporal differences possibly due to hormonal changes could be observed suggesting a precise regulation of the IL-1 system, especially for IL-1ra and moreover a stable molecular architecture within the full length of the fallopian tube.

Decreased levels of peritoneal interleukin-1 receptor antagonist in patients with endometriosis and disease-related dysmenorrhea

OBJECTIVE

To determine the level of interleukin-1 receptor antagonist (IL-1ra) in peritoneal fluid (PF) and serum in patients with endometriosis.

DESIGN

A prospective analytical study.

SETTING

University-affiliated obstetrics and gynecology academic training hospital.

PATIENT(S)

One hundred eighteen patients underwent laparoscopy for benign gynecologic diseases.

INTERVENTION(S)

Peripheral blood and PF were obtained before and during surgical procedures, and the levels of IL-1ra were measured.

MAIN OUTCOME MEASURE(S)

The concentrations of IL-1ra in PF and serum were correlated with the presence of endometriosis, disease stage, and the phase of menstrual cycle.

RESULT(S)

Peritoneal fluid IL-1ra concentrations were significantly lower in patients with endometriosis than in patients without endometriosis. Peritoneal fluid IL-1ra concentrations decreased with the increased severity of endometriosis and also decreased in disease-related dysmenorrhea; serum IL-1ra levels showed no significant difference between the patients with and without endometriosis. The concentrations of IL-1ra in PF and serum were not correlated with the phase of menstrual cycle.

CONCLUSION(S)

Our results suggested that decreased levels of PF IL-1ra in patients with endometriosis and disease-related dysmenorrhea may play an important role in the pathogenesis of this disease.

Biomarkers of endometrial receptivity--a review

Implantation is a phenomenon that involves an interaction between the embryo and maternal endometrium. There is, in the menstrual cycle, a short and precise period of time in which the maternal-embryonic interaction is optimal and culminates with adhesion and invasion of the blastocyst into the progesterone-induced secretory endometrium. This period is called nidation or implantation window. In the implantation window changes occur in endometrial epithelial morphology, characterized by the appearance of membrane projections called pinopodes. Pinopodes are progesterone-dependent organelles, that look like apical cellular protrusions appearing between days 20 and 21 of the natural menstrual cycle. There are many factors that regulate the changes typical of the implantation window and the appearance of the pinopodes. The embryonic and maternal expression of growth factors and cytokines, calcitonin, HOX genes and cell adhesion molecules might all play a major role in the phenomenon of implantation. The cytokines function as chemical messengers and can serve as biomarkers of uterine receptivity. Understanding the function of these biomarkers and their role in determining the implantation window in women, will help us to diagnose and treat infertile couples more efficiently.

Interleukin-1 system and sex steroid receptor gene expression in human endometrial cancer

OBJECTIVES

The interleukin-1 system is known to play a pivotal role in human physiology and reproduction. In the cycling endometrium, interleukin-1alpha activity is controlled by sex steroids and is confined to the perimenstrual phase, where it is involved in the events leading to tissue lysis and menstruation. Since local tissue degradation is also a feature of malignant tumors, our goal was to analyze the gene expression of interleukin-1alpha and other interleukin-1 family members and compare it with estrogen receptor alpha, estrogen receptor beta, and progesterone receptor mRNA expression in 27 endometrial carcinomas and 13 normal endometria.

METHODS

Endometrial tumor tissues were obtained during hysterectomy for endometrial cancer, and normal endometrium was sampled in women undergoing surgical procedures for nonendometrial pathologies. Gene expression was analyzed by reverse transcription polymerase chain reaction. Protein expression was detected and localized by immunohistochemical staining.

RESULTS

A strong gene expression of interleukin-1 type I receptor, estrogen recptor alpha, and progesterone receptor was detected in all tumor tissues and in the majority of benign endometrial tissues. However, in contrast to nonmalignant endometria, variable amounts of interleukin-1beta and interleukin-1 receptor antagonist mRNA were also detected in most of the tumor samples. Gene expression of interleukin-1alpha and estrogen receptor beta was considerably less frequent, with interleukin-1alpha being absent in all peri- and postmenopausal endometria and in all but one of the well-differentiated tumors. With decreasing differentiation interleukin-1alpha gene expression became more frequent. In these cases, interleukin-1alpha protein was detected predominantly in epithelial tumor cells of lower-grade tumors.

CONCLUSION

We have demonstrated the presence of the interleukin-1 system in endometrial malignancies, and found a negative correlation between interleukin-1alpha and tumor differentiation. We hypothesize that the nonphysiological expression of interleukin-1alpha in less differentiated tumors might contribute to their invasiveness and malignant behavior.