Identification of surface markers for prospective isolation of human endometrial stromal colony-forming cells

BACKGROUND: Human endometrium is a highly regenerative tissue. We hypothesizedthat the source of endometrial stromal and vascular regenerationis a resident stromal stem/progenitor cell population. Putativehuman endometrial stromal stem/progenitor cells have been identifiedusing clonal assays, a retrospective functional stem cell assay.Therefore, the aim of this study was to screen potential stemcell markers for the prospective isolation of human endometrialstromal stem/progenitor cells and to determine their capacityto identify colony-forming stromal cells. METHODS: Single-cell suspensions of human endometrial stromal cells weresorted using fluorescence-activated cell sorting into positiveand negative populations based on STRO-1, CD133, CD90 or CD146expression for clonal assays. All markers were immunolocalizedin human endometrium. RESULTS: Small populations (2–9%) of human endometrial stromalcells expressed each of the markers. Only CD146⁺ cells wereenriched for colony-forming cells, and CD90^hi cells showed atrend for greater enrichment compared with CD90^lo cells. STRO-1and CD146 were localized to perivascular cells of the endometrium.CD90 was strongly expressed by functionalis stroma and perivascularcells, but only weakly expressed in the basalis stroma. CD133was expressed by epithelial cells of the endometrium, ratherthan by stroma or perivascular cells. CONCLUSIONS: This study identified CD146 as a marker of colony-forming humanendometrial stromal cells supporting the concept that humanendometrium contains a population of candidate stromal stem/progenitorcells.     

Fas antigen (CD95) mediates cell survival signals to regulate functional cellular subpopulations in normal human endometrial stromal cells

Fas antigen (CD95) is expressed on almost all types of human cells and is believed to mediate receptor-specific apoptotic signals. In human endometrial tissues, high Fas and Fas ligand expressions and Fas-mediated apoptosis in endometrial epithelial cells have been discussed in many reports but no study has examined Fas-mediated signals in endometrial stromal cells. In this study we investigated Fas expression and Fas-mediated signals of normal human endometrial stromal cells. Flow cytometric analysis revealed Fas antigen expression on the stromal cells and their Fas expression was enhanced by 8-Br-cAMP, a strong inducer of decidualization. Neither short-term nor long-term cultures with anti-Fas IgM affected proliferation or viability of the stromal cells. Anti-Fas IgM alone affected neither viable cell numbers nor PRL release of unstimulated stromal cells. However, anti-Fas IgM dose-dependently stimulated viable cell numbers of stromal cells co-stimulated with 8-Br-cAMP and anti-Fas IgM, whereas PRL secretion of the co-stimulated cells was not affected. Anti-Fas IgM dose-dependently stimulated viable cell numbers of 8-Br-cAMP-stimulated cells but did not affect PRL secretion of 8-Br-cAMP-induced decidualized cells. These results indicate that Fas antigen on human endometrial stromal cells cannot mediate receptor-specific apoptotic signals, and that Fas-mediated signals stimulate survival of 8-Br-cAMP-stimulated non-decidualized stromal cells. Thus, stimulation of Fas-antigen on the endometrial stromal cells enhances anti-apoptotic/survival signals in certain stromal cells, autoregulating functional cellular subpopulations of human endometrial stromal cells in a paracrine manner.     

Co-expression of two perivascular cell markers isolates mesenchymal stem-like cells from human endometrium

BACKGROUND: Human endometrium has immense regenerative capacity, growing ~5 mm in 7 days every month. We have previously identified a small population of colony-forming endometrial stromal cells which we hypothesize are mesenchymal stem cells (MSC). The aim of this study was to determine if the co-expression of two perivascular cell markers, CD146 and platelet-derived growth factor-receptor beta (PDGF-Rbeta), will prospectively isolate endometrial stromal cells which exhibit MSC properties, and determine their location in human endometrium. METHODS: Single cell suspensions of human endometrial stromal cells were fluorescence activated cell sorting (FACS) sorted into CD146(+)PDGF-Rbeta(+) and CD146(-)PDGF-Rbeta(-) populations and analysed for colony-forming ability, in vitro differentiation and expression of typical MSC markers. Full thickness human endometrial sections were co-stained for CD146 and PDGF-Rbeta. RESULTS: FACS stromal CD146(+)PDGF-Rbeta(+) stromal cells (1.5% of sorted population) were enriched for colony-forming cells compared with CD146(-)PDGF-Rbeta(-) cells (7.7 +/- 1.7 versus 0.7 +/- 0.2% P <0.0001), and also underwent differentiation into adipogenic, osteogenic, myogenic and chondrogenic lineages. They expressed MSC phenotypic surface markers and were located near blood vessels. CONCLUSION: This study shows that human endometrium contains a small population of MSC-like cells that may be responsible for its cyclical growth, and may provide a readily available source of MSC for tissue engineering applications.     

The expression profile of micro-RNA in endometrium and endometriosis and the influence of ovarian steroids on their expression

MicroRNAs (miRNAs), through mRNA degradation or repression, act as key regulator of gene expression. Our aim was to identify specific miRNAs that are expressed in endometrium of women with and without endometriosis. We profiled the expression of 287 miRNAs in paired eutopic and ectopic endometrium and isolated endometrial cells using microarray and validated the expression of selected miRNAs using real-time PCR. On the basis of global normalization, 65 of these miRNAs were identified to be expressed above the threshold levels set during the analysis in the endometrium of women without endometriosis with a progressive decline in expression in paired eutopic and ectopic endometrium. Statistical analysis (ANOVA) identified 48 of these miRNAs as differentially expressed among these tissues and 32 miRNAs between isolated endometrial stromal cell (ESC) and glandular epithelial cell (GEC) (P < 0.05). The expression of hsa-miR20a, hsa-miR21, hsa-miR26a, hsa-miR18a, hsa-miR206, hsa-miR181a and hsa-miR142-5p, predicted to target many genes, including TGF-betaR2, ERalpha, ERbeta and PR, respectively, was validated in these tissues and cells using real-time PCR. Treatment of ESC and GEC with 17beta-estradiol and medroxyprogesterone acetate (10(-8) M) differentially regulated the expression of hsa-miR20a, hsa-miR21 and hsa-miR26a, which in part reversed following co-treatment with ICI-182780 and RU-486 (10(-6) M), respectively (P < 0.05). In conclusion, we provided evidence for the expression of a number of differentially expressed miRNAs in eutopic/ectopic endometrium and isolated endometrial cells, opening up the possibility that aberrant/altered expression of some miRNAs whose expression is regulated by the ovarian steroids may influence the expression of specific target genes with central roles in normal endometrial cellular activities and pathogenesis of endometriosis.     

Interleukin-34 accelerates intrauterine adhesions progress related to CX3CR1+ monocytes/macrophages

Intrauterine adhesions (IUA) are characterized by endometrial fibrosis and impose a great challenge for female reproduction. IL-34 is profoundly involved in various fibrotic diseases through regulating the survival, proliferation, and differentiation of monocytes/macrophages. However, it remains unclear how IL-34 regulates monocytes/macrophages in context of IUA. Here, we showed that the expression level of IL-34 and the amount of CX3CR1+ monocytes/macrophages were significantly increased in endometrial tissues of IUA patients. IL-34 promoted the differentiation of monocytes/macrophages, which express CX3CR1 via CSF-1R/P13K/Akt pathway in vitro. Moreover, IL-34-induced CX3CR1+ monocytes/macrophages promoted the differentiation of endometrial stromal cells into myofibroblasts. Of note, IL-34 caused endometrial fibrosis and increased the amount of CX3CR1+ monocytes/macrophages in endometrial tissues in vivo. IL-34 modulated endometrial fibrosis by regulating monocytes/macrophages since the elimination of endometrial monocytes/macrophages significantly suppressed the profibrotic function of IL-34. Finally, blocking of IL-34 in the LPS-IUA model resulted in the improvement of endometrial fibrosis and decreased number of CX3CR1+ monocytes/macrophages. Our studies uncover the novel mechanism of interaction between IL-34-induced CX3CR1+ monocytes/macrophages and endometrial stromal cells in endometrial fibrosis pathogenesis, and highlight IL-34 as a critical target for treating IUA.     

Secretory endometrium highly expresses urocortin messenger RNA and peptide: possible role in the decidualization process

BACKGROUND: Urocortin (UCN) gene expression and synthesis have been reported in epithelial and stromal cells of the human endometrium. In this study we evaluated (i) UCN messenger RNA (mRNA) expression and peptide production in uterine specimens collected throughout the endometrial cycle, (ii) UCN secretion after decidualization of cultured human endometrial stromal cells (HESCs) and (iii) the effect of UCN on endometrial decidualization. METHODS: HESCs were isolated from samples of human endometrium collected from healthy patients with normal menstrual cycle and cultured in presence of cAMP, 17-beta-estradiol (E(2)) + medroxyprogesterone acetate (MPA) and UCN. UCN levels were measured in endometrial extracts by an enzyme immunoassay, and changes of endometrial UCN mRNA expression were measured by RT-PCR analysis. RESULTS: UCN peptide concentrations and mRNA expression were highest in the secretory phase of the menstrual cycle (P < 0.001, late secretory versus early and late proliferative phase) and higher in the late than the early secretory phase (P < 0.01). After decidualization of HESC with cAMP or E(2) + MPA, UCN levels rose in parallel with prolactin concentrations by days 6 (P < 0.01, for all). Finally, the addition of UCN to HESCs, with or without E(2) + MPA, induced the release of prolactin. CONCLUSIONS: The evidence that (i) UCN is highly expressed in the secretory phase of the endometrial cycle; (ii) cAMP and E(2) + MPA modulate secretion of UCN and (iii) UCN induces HESCs decidualization together suggest a possible role for UCN in endometrial physiology.     

Interleukin 11 advances progesterone-induced decidualization of human endometrial stromal cells

Differentiation of endometrial stromal cells into decidual cells is crucial for embryo implantation and placentation. Interleukin (IL)-11 signalling is essential for adequate decidualization in the mouse uterus. We examined the role of IL-11 during progesterone-induced decidualization of human endometrial stromal cells over a 10-12 day period, using prolactin (PRL) production as a decidual marker. These cells produced biologically active IL-11 and expressed IL-11, IL-11Ralpha and PRL mRNA during decidualization. Neutralization of endogenous IL-11 with an anti-human (hu)IL-11 antibody (AB) reduced production of PRL from day 8 and insulin-like growth factor binding protein (IGFBP)-1, another marker of decidualization, from day 10 of culture. Following AB washout, PRL and IGFBP-1 secretion increased. Addition of recombinant (r)huIL-11 (10 or 100 ng/ml) to endometrial stromal cells increased secretion of PRL from day 4 and IGFBP-1 from day 6 compared with progesterone alone. Morphological signs of differentiation accompanied biochemical differentiation in the progesterone-treated cells and were further induced by exogenous rhuIL-11. Our observations demonstrate that human endometrial stromal cells produce biologically active IL-11, which promotes progesterone-induced decidualization. These results suggest that IL-11 has both paracrine and autocrine actions on human endometrial stromal cells and plays an important role in preparing the human endometrium for implantation.     

Human endometrial peptides: a review of their potential role in implantation and placentation.

This paper reviews human endometrial peptide synthesis and discusses the biological function of these peptides in relation to implantation and placentation. Despite the substantial literature on quantitative and qualitative peptide synthesis by the endometrium, it has not been possible to define the function of most of these substances. Various aspects of endometrial morphology, especially the endometrial leukocytes, are discussed in an attempt to relate cellular structure and function. A number of serum proteins are produced by the endometrial glandular epithelium and may play a role in early embryo development. Extracellular matrix proteins produced by stromal cells are important for endometrial structure and integrity but also provide a site for trophoblast attachment. Several hormones and binding proteins are also produced by stromal cells and probably influence endometrial metabolism. Complement factors and secretory component may have a role in maintaining a sterile intrauterine environment. Many other endometrial proteins have been less well characterized and their role in endometrial physiology at present remains uncertain. Perhaps the most exciting advance has been the realization that a number of peptide regulatory factors (cytokines and growth factors) are not only produced by the endometrium but play an integral part in the mediation of oestrogen-induced growth and differentiation of the endometrium and with the local metabolic and physiological processes.     

大鼠子宫腔粘连模型的构建与改进

目的 宫腔粘连是一种严重损害女性生殖健康的疾病。为了进一步研究宫腔粘连的发生机制,采用经典的子宫内膜刮除法制作宫腔粘连大鼠模型,并对该模型进行评价和改进。 方法 60只SD大鼠随机分为3组：假手术组、子宫内膜刮除组和子宫内膜及部分间质刮除组,每组20只。假手术组打开宫腔后即缝合并关腹。子宫内膜刮除组用刀片刮除双侧子宫内膜。子宫内膜及部分间质刮除组用刀片刮除双侧子宫内膜和间质层,直至表面有粗糙感为止。术后3、7、14、21、28 d取材,行组织学和免疫组织化学评估。 结果 刮宫后两组大鼠子宫内膜上皮层消失,子宫内膜刮除组大鼠术后7d可发现重新长出的子宫内膜。而子宫内膜和部分间质刮除组大鼠各时间点组织学染色见上皮层消失,间质减少50%以上,腺体数目减少,子宫内膜纤维化面积比随着刮宫时间延长而增高。刮宫后转化生长因子β1的表达增高,基质金属蛋白酶9的表达降低。与宫腔黏连发生的机制相符。 结论 刮除子宫内膜和部分间质能够制备出大鼠宫腔黏连的模型,本研究宫腔黏连大鼠模型能反映宫腔粘连的组织学和病理学变化,可用于宫腔粘连的实验研究。     

Endometrial interleukin-6 in vitro is not regulated directly by female steroid hormones,but by pro-inflammatory cytokines and hypoxia

Endometrial interleukin-6 (IL-6) mRNA has been reported to be suppressed in the mid-secretory phase in patients with recurrent early spontaneous abortions. This prompted our study concerning the regulation of endometrial IL-6 in cell culture models of endometrial epithelial and stromal cells. Steroid-dependent secretion of IL-6 was analysed by 17beta-estradiol (10(-8) mol/l) or progesterone (10(-6) mol/l) treatment and withdrawal (n = 8). Regulation by pro-inflammatory cytokines was studied in co-cultures of endometrial cells with human blood peripheral mononuclear cells (PBMC; n = 5) and by stimulation with IL-1beta, IL-6 and tumour necrosis factor alpha (TNFalpha), secreted by PBMCs at high concentrations. Regulation by hypoxia was assessed by culture of endometrial cells in 2% oxygen for 6 and 24 h (n = 5). IL-6 mRNA and protein levels were analysed by RT-PCR and enzyme-linked immunosorbent assays respectively. Endometrial IL-6 was not directly affected by 17beta-estradiol and/or progesterone. Co-culturing endometrial cells with PBMCs led to an increase of stromal but not epithelial IL-6 mRNA levels. In stromal cells, IL-6 secretion increased 2-10-fold if stimulated with 10 ng/ml recombinant IL-1beta or TNFalpha (P < 0.05). Hypoxia stimulated IL-6 secretion in epithelial cells up to 2-fold and in stromal cells up to 48-fold (P < 0.05). In conclusion, IL-6 expression in stromal and epithelial cells in vitro is regulated differently by pro-inflammatory cytokines and hypoxia. These results suggest a tight and specific network of control for this important cytokine within different endometrial compartments.     

Urocortin 2 and urocortin 3 in endometriosis: evidence for a possible role in inflammatory response

Urocortin 2 (Ucn 2) and urocortin 3 (Ucn 3) are neuropeptides expressed by human endometrium. This study evaluated (i) the expression of Ucn 2 and Ucn 3 mRNA in endometriotic lesions and in endometrium of women with endometriosis; (ii) the effect of Ucn 2 and Ucn 3 on cytokines secretion from cultured endometrial stromal cells. Endometriotic tissue was collected from endometrioma (n=39); endometrial specimens were obtained from women with (n=39) and without (n=41) endometriosis throughout menstrual cycle. Tissue specimens were analysed for Ucn 2 and Ucn 3 mRNA expression and peptide localization; the effects of Ucn 2 or Ucn 3 on tumour necrosis factor (TNF-α) and interleukin (IL-4) secretion from cultured endometrial stromal cells was studied. Ucn 2 and Ucn 3 mRNA expression and localization were assessed by RT-PCR and by immuohistochemistry, respectively; cytokines secretion were measured by ELISA. Results showed that endometriotic tissue expressed both Ucn 2 and Ucn 3, with Ucn 3 expression higher in ectopic than in eutopic endometrium. Endometrial Ucn 2 mRNA expression in controls showed peak values at early proliferative phase, while in endometriotic patients low expression and no significant changes throughout menstrual cycle were observed. Endometrial Ucn 3 mRNA expression was highest in late secretory phase in controls, while in endometriotic patients low levels and no menstrual-cycle-related changes were found. When added to cultured endometrial cell cultures, Ucn 2 significantly increased TNF-α (P<0.01) and IL-4 (P<0.001), while Ucn 3 induced an increase of IL-4 secretion (P<0.01). In conclusion, endometriotic tissue expressed and localized Ucn 2 and Ucn 3; patients with endometriosis showed Ucn 2 and Ucn 3 mRNA expression in eutopic endometrium lower than in control group, with no endometrial cycle-related changes. Ucn 2 and Ucn 3-modulated TNF-α and IL-4 secretion from culture endometrial cells. These data suggest a possible involvement of Ucn 2 and Ucn 3 in the mechanisms of endometriosis.     

人早孕蜕膜间充质干细胞移植治疗大鼠宫腔粘连

目的:探讨人早孕蜕膜间充质干细胞(hDMSCs)治疗大鼠宫腔粘连(IUA)的可行性和有效性。方法:体外分离、培养、纯化、鉴定h DMSCs。将30只雌性SD大鼠随机分为3组:蜕膜间充质干细胞治疗组(IUA+hDMSCs)、IUA模型组和假手术(sham)组,每组各10只。IUA+hDMSCs组和IUA组复制IUA模型后10 min内,IUA+hDMSCs组经尾静脉注射2×10~6个Dio标记的hDMSCs,每3天补充1次,连续注射3次;IUA组经尾静脉注射相同容量的PBS;sham组仅行开腹手术。3个动情周期后取子宫行HE染色和Masson染色,测量子宫内膜厚度、子宫内膜腺体数目、子宫内膜小血管数目和纤维化面积比率,并行免疫组化检测子宫内膜组织细胞角蛋白、波形蛋白、转化生长因子(TGF)-β1及整合素αγβ3的表达量,q PCR检测IUA相关基因含量,免疫荧光观察h DMSCs在内膜中的分布情况,并评估大鼠的生育能力。结果:IUA组部分子宫腔闭锁,内膜萎缩,腺体减少,大量纤维化改变。IUA+hDMSCs组与IUA组相比子宫间质厚度明显增加(P0.05),大量腺体增生和小血管新生(P0.05),纤维化程度减小(P0.05),与sham组比较无统计学差异。IUA+hDMSCs组细胞角蛋白、波形蛋白和整合素αγβ3表达量明显高于IUA组(P0.05),而TGF-β1表达量低于IUA组(P0.05)。qPCR结果显示与IUA组相比,除TNF-α和结缔组织生长因子下调外,IUA+hDMSCs组的干细胞因子、血管内皮生长因子、碱性成纤维细胞生长因子和thrombospondin-1均明显上调。免疫荧光结果显示Dio- DMSCs主要分布于腔上皮层,部分位于间质。IUA+hDMSCs组大鼠双侧子宫均妊娠,平均胎鼠数量与IUA组相比有统计学差异(P0.05)。结论:hDMSCs可在受损的大鼠子宫内膜中存活、增殖,有效修复大鼠的子宫内膜,抑制IUA。     

A morphometric study of the human endometrial stroma during the peri-implantation period

In this study we have examined the human endometrial stromal cell population in well-timed biopsies during the peri-implantation period, using traditional stereological techniques. This paper reports data obtained from 16 women of known fertility who underwent endometrial biopsies at known times after the luteinizing hormone (LH) surge (four each at LH + 2, LH + 4, LH + 6 and LH + 8). The average stromal cell nuclear diameter increased in size throughout the period of study (P less than 0.01), with a significant decrease (P less than 0.05) in the nuclear profile axial ratio. This suggests that the nuclei were increasing in size and becoming more rounded. There was a dramatic increase (P less than 0.01) in the packing density between LH + 2 and LH + 6; this is likely to be due, at least in part, to the glands filling up with secretory products and so compressing the intervening stroma. A substantial decrease (P less than 0.01) was seen in the packing density between LH + 6 and LH + 8. This corresponds to the time when stromal oedema is thought to be maximal.     

Uterus and endometrium: Inhibition of human endometrial stromal cell proliferation by interleukin 6

We investigated the ability of interleukin 6 (IL-6) to modulatehuman endometrial stromal cell growth in vitro Stromal cellproliferation in response to treatment with varying concentrationsof IL-6 was determined. Endometrial tissue was obtained from10 normally cycling women during the secretory phase of theirmenstrual cycle. Treatment with IL-6 resulted in a dose- andcell-density-dependent inhibition of endometrial stromal cellproliferation in vitro. The maximal inhibition was observedwith 200 pg/ml of IL-6 and at a concentration of 10⁵ cells/well.During in-vitro culture, stromal cells produced low amountsof IL-6 and demonstrated the presence of IL-6 receptor. Thesedata demonstrate that IL-6 acts as a growth-regulatory signalfor human endometrial stromal cells. We postulate that IL-6may contribute to the maintenance of homeostasis in normal endometriumand that perturbation of IL-6 mediated responses may play arole in disorders of the endometrium such as endometrial cancerand endometriosis.     

Insulin-like growth factor binding protein-1 induces decidualization of human endometrial stromal cells via alpha5beta1 integrin

Progesterone is known to induce decidualization of human endometrial stromal cells in vitro. Decidualized stromal cells produce insulin-like growth factor binding protein-1 (IGFBP-1) as well as prolactin (PRL). In this study, we tested the possibility that IGFBP-1 directly stimulates endometrial stromal cell decidualization. Endometrial stromal cells were obtained from normal menstruating patients with uterine myoma at hysterectomy. Stromal cells were cultured for up to 4 weeks with estradiol (E(2)) and/or medroxy progesterone acetate (MPA) in the presence or the absence of IGFBP-1 and, LR(3)-IGF-I (an IGF-I analogue) that binds to the IGF-I receptor but has reduced affinity for IGFBPs. Decidualization of endometrial stromal cells was evaluated by morphological changes and PRL release into culture media. The binding of IGFBP-1 to endometrial cells was analysed using a biosensor. MPA and E(2) induced decidualization of stromal cells, while LR(3)-IGF-I inhibited decidualization by MPA and E(2) as well as PRL and IGFBP-1 secretion into medium. IGFBP-1 induced decidualization of stromal cells in the absence of MPA and E(2) in the medium. IGFBP-1-induced decidualization was not inhibited by the addition of LR(3)IGF-1 but was inhibited by the addition of an RGD peptide, however, the RGD peptide had no effect on decidualization when added alone. The binding analysis showed that IGFBP-1 bound to the surface of endometrial stromal cells and an anti-alpha5beta1 integrin antibody inhibited its binding. These results suggest that IGFBP-1 produced by endometrium can mediate progesterone-induced decidualization possibly by interacting with alpha5beta1 integrin on the surface of endometrial stromal cells.     

A morphometric study of the human endometrial stroma during the peri-implantation period

In this study we have examined the human endometrial stromal cell population in well-timed biopsies during the peri-implantation period, using traditional stereological techniques. This paper reports data obtained from 16 women of known fertility who underwent endometrial biopsies at known times after the luteinizing hormone (LH) surge (four each at LH + 2, LH + 4, LH + 6 and LH + 8). The average stromal cell nuclear diameter increased in size throughout the period of study (P less than 0.01), with a significant decrease (P less than 0.05) in the nuclear profile axial ratio. This suggests that the nuclei were increasing in size and becoming more rounded. There was a dramatic increase (P less than 0.01) in the rounded. There was a dramatic increase (P less than 0.01) in the packing density between LH + 2 and LH + 6; this is likely to be due, at least in part, to the glands filling up with secretory products and so compressing the intervening stroma. A substantial decrease (P less than 0.01) was seen in the packing density between LH + 6 and LH + 8. This corresponds to the time when stromal oedema is thought to be maximal.     

Involvement of insulin-like growth factor-binding protein-related protein 1 in decidualization of human endometrial stromal cells

Uterine decidualization is crucial for successful implantation and the establishment of pregnancy. In the present study, the expression of insulin-like growth factor-binding protein (IGFBP)-related protein 1 (IGFBP-rP1) in the human uterus and endometrial stromal cells (ESCs) and its physiological significance in decidualization were examined. IGFBP-rP1 protein was localized in the glandular epithelium and stromal cells, and blood vessels in the endometrium. Cultured stromal cells expressed IGFBP-rP1 and secreted it into the medium. IGFBP-rP1 was localized mostly in the cytoplasm near the nucleus. Knocking down the endogenous IGFBP-rP1 expression in stromal cells, by a small interfering (si)RNA, diminished the expression of prolactin and IGFBP-1 which serve as decidual markers. These results suggest that IGFBP-rP1 may play a role in decidualization of ESCs.     

Generation of human tumor-reactive cytotoxic T cells against peptides presented by non-self HLA class I molecules

The cyclin-D1 protein, which was found to be overexpressed in various human tumors, promotes cell cycle progression from the G1 into the S phase. It is normally expressed at low levels in several tissues and is likely to induce immunological tolerance. We have recently shown in a murine system that T cell tolerance to a widely expressed protein was circumvented by raising cytotoxic T lymphocytes (CTL) from major histocompatability complex mismatched donors. In this study, we tested whether it is possible to raise human allo-restricted CTL against the cyclin-D1 protein. The human cell line T2 is deficient in the genes encoding the transporter associated with antigen processing (TAP), resulting in inefficient loading of HLA-A2 class I molecules with endogenous peptides. Thus, a large number of A2 molecules can bind exogenously supplied synthetic peptides. Peripheral blood mononu clear cells from HLA-A2-negative donors were stimulated with T2 cells presenting cyclin-D1-derived synthetic peptides. Cloning of bulk cultures revealed that a large proportion of CTL clones were peptide specific. One peptide induced CTL which lysed cyclin-D1-expressing breast cancer cells, but not control Epstein-Barr virus-transformed B lymphoid cells. The results show that HLA-A2-negative donors can be used to isolate tumor-reactive CTL spe cific for cyclin-D1 peptides presented by HLA-A2 class I molecules.