The thymus and the science of self.

The conventional perception asserts that immunology is the science of 'discrimination' between self and non-self. This concept is however no longer tenable as effector cells of the adaptive immune system are first conditioned to be tolerant to the body's own antigens, collectively known as self until now. Only then attain these effectors the responsiveness to non-self. The acquisition of this essential state of tolerance to self occurs for T cells in the thymus, the last major organ of our body that revealed its intricate function in health and disease. The 'thymus' as an anatomical notion was first notably documented in Ancient Greece although our present understanding of the organ's functions was only deciphered commencing in the 1960s. In the late 1980s, the thymus was identified as the site where clones of cells reactive to self, termed 'forbidden' thymocytes, are physically depleted as the result of a process now known as negative selection. The recognition of this mechanism further contributed to the belief that the central rationale of immunology as a science lies in the distinction between self and non-self. This review will discuss the evidence that the thymus serves as a unique lymphoid organ able to instruct T cells to recognize and be tolerant to harmless self before adopting the capacity to defend the body against potentially injurious non-self-antigens presented in the context of different challenges from infections to exposure to malignant cells. The emerging insight into the thymus' cardinal functions now also provides an opportunity to exploit this knowledge to develop novel strategies that specifically prevent or even treat organ-specific autoimmune diseases.

Human Chorionic Gonadotrophin: New Pleiotropic Functions for an "Old" Hormone During Pregnancy.

Human chorionic gonadotrophin (hCG) is the first specific molecule synthesized by the embryo. hCG RNA is transcribed as early as the eight-cell stage, and the blastocyst produces the protein before its implantation. hCG in the uterine microenvironment binds with its cognate receptor, luteinizing hormone/choriogonadotropin receptor (LHCGR), on the endometrial surface. This binding stimulates leukemia inhibitory factor (LIF) production and inhibits interleukin-6 (IL-6) production by epithelial cells of the endometrium. These effects ensure essential help in the preparation of the endometrium for initial embryo implantation. hCG also effects angiogenic and immunomodulatory actions as reported in many articles by our laboratories and other ones. By stimulating angiogenesis and vasculogenesis, hCG provides the placenta with an adequate maternal blood supply and optimal embryo nutrition during the invasion of the uterine endometrium. The immunomodulatory properties of hCG are numerous and important for programming maternal immune tolerance toward the embryo. The reported effects of hCG on uterine NK, Treg, and B cells, three major cell populations for the maintenance of pregnancy, demonstrate the role of this embryonic signal as a crucial immune regulator in the course of pregnancy. Human embryo rejection for hCG-related immunological reasons has been studied in different ways, and a sufficient dose of hCG seems to be necessary to maintain maternal tolerance. Different teams have studied the addition of hCG in patients suffering from recurrent miscarriages or implantation failures. hCG could also have a beneficial or a negative impact on autoimmune diseases during pregnancy. In this review, we will discuss the immunological impacts of hCG during pregnancy and if this hormone might be used therapeutically.

The presentation of neuroendocrine self-peptides in the thymus: an essential event for individual life and vertebrate survival.

Confirming Burnet's early hypothesis, elimination of self-reactive T cells in the thymus was demonstrated in the late 1980s, and an important question immediately arose about the nature of the self-peptides expressed in the thymus. Many genes encoding neuroendocrine-related and tissue-restricted antigens (TRAs) are transcribed in thymic epithelial cells (TECs). They are then processed for presentation by proteins of the major histocompatibility complex (MHC) expressed by TECs and thymic dendritic cells. MHC presentation of self-peptides in the thymus programs self-tolerance by two complementary mechanisms: (1) negative selection of self-reactive "forbidden" T cell clones starting already in fetal life, and (2) generation of self-specific thymic regulatory T lymphocytes (tTreg cells), mainly after birth. Many studies, including the discovery of the transcription factors autoimmune regulator (AIRE) and fasciculation and elongation protein zeta family zinc finger (FEZF2), have shown that a defect in thymus central self-tolerance is the earliest event promoting autoimmunity. AIRE and FEZF2 control the level of transcription of many neuroendocrine self-peptides and TRAs in the thymic epithelium. Furthermore, AIRE and FEZF2 mutations are associated with the development of autoimmunity in peripheral organs. The discovery of the intrathymic presentation of self-peptides has revolutionized our knowledge of immunology and is opening novel avenues for prevention/treatment of autoimmunity.

Conversion to Graves disease from Hashimoto thyroiditis: a study of 24 patients

ABSTRACT Objective: The conversion of Hashimoto's thyroiditis (HT) to hyperthyroidism due to thyrotropin receptor antibodies is intriguing and considered rare. The contribution of TSH receptor blocking antibodies (TRAb), which may be stimulators (TSAb) or blockers (TBAb), is suspected. We describe clinical and biological variables in a series of patients switching from Hashimoto's thyroiditis to Grave's disease. Subjects and methods: Retrospective case study of 24 patients with Hashimoto's thyroiditis followed during 48 ± 36 months that developed later Graves' disease (GD). These variables were analysed in the hypo and hyperthyroid phase: age, sex, initial TSH, free triiodothyronine (fT3), free thyroxine (fT4), anti-TPO, TBII antibodies, parietal cell autoantibodies, time between hypo and hyperthyroidism, thyroid volume and levothyroxine doses (LT). Results: In HT, mean TSH was 9.4 ± 26.1 UI/L and levothyroxine treatment was 66.2 ± 30.8 µg/day. The switch to GD was observed 38 ± 45 months after HT diagnosis. As expected, we found significant differences on TSH, FT3, FT4 and TBAb levels. Three out of 14 patients had parietal cell autoantibodies. In two of these three cases there was an Helicobacter pylori infection. There were no significant differences between HT and GD groups with respect to thyroid volume. Conclusions: To our knowledge, large series documenting the conversion of HT to GD are scarce. Although rare, this phenomenon should not be misdiagnosed. Suspicion should be raised whenever thyroxine posology must be tapered down during the follow-up of HT patients. Further immunological and genetic studies are needed to explain this unusual autoimmune change.

Oxytocin in survivors of childhood-onset craniopharyngioma.

Quality of survival of childhood-onset craniopharyngioma patients is frequently impaired by hypothalamic involvement or surgical lesions sequelae such as obesity and neuropsychological deficits. Oxytocin, a peptide hormone produced in the hypothalamus and secreted by posterior pituitary gland, plays a major role in regulation of behavior and body composition. In a cross-sectional study, oxytocin saliva concentrations were analyzed in 34 long-term craniopharyngioma survivors with and without hypothalamic involvement or treatment-related damage, recruited in the German Childhood Craniopharyngioma Registry, and in 73 healthy controls, attending the Craniopharyngioma Support Group Meeting 2014. Oxytocin was measured in saliva of craniopharyngioma patients and controls before and after standardized breakfast and associations with gender, body mass index, hypothalamic involvement, diabetes insipidus, and irradiation were analyzed. Patients with preoperative hypothalamic involvement showed similar oxytocin levels compared to patients without hypothalamic involvement and controls. However, patients with surgical hypothalamic lesions grade 1 (anterior hypothalamic area) presented with lower levels (p = 0.017) of oxytocin under fasting condition compared to patients with surgical lesion of posterior hypothalamic areas (grade 2) and patients without hypothalamic lesions (grade 0). Craniopharyngioma patients' changes in oxytocin levels before and after breakfast correlated (p = 0.02) with their body mass index. Craniopharyngioma patients continue to secrete oxytocin, especially when anterior hypothalamic areas are not involved or damaged, but oxytocin shows less variation due to nutrition. Oxytocin supplementation should be explored as a therapeutic option in craniopharyngioma patients with hypothalamic obesity and/or behavioral pathologies due to lesions of specific anterior hypothalamic areas. Clinical trial number: KRANIOPHARYNGEOM 2000/2007(NCT00258453; NCT01272622).

How Does Thymus Infection by Coxsackievirus Contribute to the Pathogenesis of Type 1 Diabetes?

Through synthesis and presentation of neuroendocrine self-antigens by major histocompatibility complex proteins, thymic epithelial cells (TECs) play a crucial role in programing central immune self-tolerance to neuroendocrine functions. Insulin-like growth factor-2 (IGF-2) is the dominant gene/polypeptide of the insulin family that is expressed in TECs from different animal species and humans. Igf2 transcription is defective in the thymus of diabetes-prone bio-breeding rats, and tolerance to insulin is severely decreased in Igf2 (-/-) mice. For more than 15 years now, our group is investigating the hypothesis that, besides a pancreotropic action, infection by coxsackievirus B4 (CV-B4) could implicate the thymus as well, and interfere with the intrathymic programing of central tolerance to the insulin family and secondarily to insulin-secreting islet ß cells. In this perspective, we have demonstrated that a productive infection of the thymus occurs after oral CV-B4 inoculation of mice. Moreover, our most recent data have demonstrated that CV-B4 infection of a murine medullary (m) TEC line induces a significant decrease in Igf2 expression and IGF-2 production. In these conditions, Igf1 expression was much less affected by CV-B4 infection, while Ins2 transcription was not detected in this cell line. Through the inhibition of Igf2 expression in TECs, CV-B4 infection could lead to a breakdown of central immune tolerance to the insulin family and promote an autoimmune response against insulin-secreting islet ß cells. Our major research objective now is to understand the molecular mechanisms by which CV-B4 infection of TECs leads to a major decrease in Igf2 expression in these cells.

Evidence for cross-talk between the LH receptor and LH during implantation in mice.

The present study investigated the first interaction that occurs between the blastocyst and endometrium during implantation. Given the ethical objections to studying implantation in humans, a mouse model was used to study the dialogue between luteinising hormone (LH) and luteinising hormone receptor (LHCGR). Several studies performed on LHCGR-knockout mice have generated controversy regarding the importance of the dialogue between LH and LHCGR during implantation. There has been no demonstration of a bioactive LH-like signal produced by the murine blastocyst. The first aim of the present study was to examine and quantify, using radioimmunoassay, the generation of a bioactive LH signal by the murine blastocyst. We went on to examine and quantify endometrial Lhcgr expression to validate the mouse model. Expression of LHCGR in mouse uteri was demonstrated using immunohistochemistry and western blot analysis. To quantify the expression of Lh in the mouse blastocyst and Lhcgr in the endometrium, reverse transcription-polymerase chain reaction (RT-PCR) and real-time quantitative (q) RT-PCR were performed. The results demonstrate that Lhcgr expression in BALB/c mouse endometrial epithelium is increased at the time of implantation and indicate that LHCGR may contribute to the implantation process. In support of this hypothesis, we identified a bioactive LH signal at the time of murine blastocyst implantation.

Persistent infection of thymic epithelial cells with coxsackievirus B4 results in decreased expression of type 2 insulin-like growth factor.

It has been hypothesized that a disturbance of central self-tolerance to islet ß cells may play a role in the enteroviral pathogenesis of type 1 diabetes. Whether enteroviruses can induce an impaired expression of ß-cell self-antigens in thymic epithelial cells has been investigated in a murine thymic epithelial (MTE) cell line. This cell line was permissive to the diabetogenic group B4 coxsackievirus (CV-B4) strain CV-B4 E2 and spontaneously expressed type 2 insulin-like growth factor (Igf2), the dominant self-antigen of the insulin family. In this model, a persistent replication of CV-B4 E2 was obtained, as attested to by the prolonged detection of intracellular positive- and negative-strand viral RNA by reverse transcription-PCR (RT-PCR) and capsid protein VP1 by immunofluorescent staining and by the release of infectious particles in culture supernatants. The chronic stage of the infection was characterized by a low proportion of VP1-positive cells (1 to 2%), whereas many cells harbored enteroviral RNA, as displayed by RT-PCR without extraction applied directly to a few cells. Igf2 mRNA and IGF-2 protein were dramatically decreased in CV-B4 E2-infected MTE cell cultures compared with mock-infected cultures, whereas housekeeping and interleukin-6 (Il6) gene expression was maintained and Igf1 mRNA was decreased, but to a lower extent. Inoculation of CV-B3, CV-B4 JVB, or echovirus 1 resulted in a low level of IGF-2 in culture supernatants as well, whereas herpes simplex virus 1 stimulated the production of the protein. Thus, a persistent infection of a thymic epithelial cell line with enteroviruses like CV-B4 E2 can result in a disturbed production of IGF-2, a protein involved in central self-tolerance toward islet ß cells.

Management of inflammatory bowel disease in pregnancy.

BACKGROUND AND AIMS: Inflammatory bowel disease (IBD) is a chronic disease affecting mainly young people in their reproductive years. IBD therefore has a major impact on patients' family planning decisions. Management of IBD in pregnancy requires a challenging balance between optimal disease control and drug safety considerations. This article aims to provide a framework for clinical decision making in IBD based on review of the literature on pregnancy-related topics. METHODS: Medline searches with search terms 'IBD', 'Crohn's disease' or 'ulcerative colitis' in combination with keywords for the topics fertility, pregnancy, congenital abnormalities and drugs names of drugs used for treatment of IBD. RESULTS: IBD patients have normal fertility, except for women after ileal pouch-anal anastomosis (IPAA) and men under sulfasalazine treatment. Achieving and maintaining disease remission is a key factor for successful pregnancy outcomes in this population, as active disease at conception carries an increased risk of preterm delivery and low birth weight. Clinicians should discuss the need for drug therapy to maintain remission with their patients in order to ensure therapy compliance. Most IBD drugs are compatible with pregnancy, except for methotrexate and thalidomide. If possible, anti-TNF therapy should be stopped by the end of the second trimester and the choice of delivery route should be discussed with the patient. CONCLUSIONS: Disease control prior to conception and throughout pregnancy is the cornerstone of successful pregnancy management in IBD patients.

Expression of the growth hormone/insulin-like growth factor axis during Balb/c thymus ontogeny and effects of growth hormone upon ex vivo T cell differentiation.

AIMS: We address the question of the expression and the role of the growth hormone/insulin-like growth factor (GH/IGF) axis in the thymus. METHODS: Using RT-qPCR, the expression profile of various components of the somatotrope GH/IGF axis was measured in different thymic cell types and during thymus embryogenesis in Balb/c mice. The effect of GH on T cell differentiation was explored via thymic organotypic culture. RESULTS: Transcription of Gh, Igf1, Igf2 and their related receptors predominantly occurred in thymic epithelial cells (TEC), while a low level of Gh and Igf1r transcription was also evidenced in thymic T cells (thymocytes). Gh, Ghr, Ins2, Igf1, Igf2, and Igfr1 displayed distinct expression profiles depending on the developmental stage. The protein concentrations of IGF-1 and IGF-2 were in accordance with the profile of their gene expression. In fetal thymus organ cultures (FTOC) derived from Balb/c mice, treatment with exogenous GH resulted in a significant increase of double negative CD4-CD8- T cells and CD4+ T cells, together with a decrease in double positive CD4+CD8+ T cells. These changes were inhibited by concomitant treatment with GH and the GH receptor (GHR) antagonist pegvisomant. However, GH treatment also induced a significant decrease in FTOC Gh, Ghr and Igf1 expression. CONCLUSION: These data show that the thymotropic properties of the somatotrope GH/IGF-1 axis involve an interaction between exogenous GH and GHR expressed by TEC. Since thymic IGF-1 is not increased by GH treatment, the effects of GH upon T cell differentiation could implicate a different local growth factor or cytokine.

Rheumatoid arthritis and pregnancy: evolution of disease activity and pathophysiological considerations for drug use.

It has long been known that pregnancy and childbirth have a profound effect on the disease activity of rheumatic diseases. For clinicians, the management of patients with RA wishing to become pregnant involves the challenge of keeping disease activity under control and adequately adapting drug therapy during pregnancy and post-partum. This article aims to summarize the current evidence on the evolution of RA disease activity during and after pregnancy and the use of anti-rheumatic drugs around this period. Of recent interest is the potential use of anti-TNF compounds in the preconception period and during pregnancy. Accumulating experience with anti-TNF therapy in other immune-mediated inflammatory diseases, such as Crohn's disease, provides useful insights for the use of TNF blockade in pregnant women with RA, or RA patients wishing to become pregnant.

Thymic recovery after allogeneic hematopoietic cell transplantation with non-myeloablative conditioning is limited to patients younger than 60 years of age.

BACKGROUND: Long-term immune recovery in older patients given hematopoietic cell transplantation after non-myeloablative conditioning remains poorly understood. This prompted us to investigate long-term lymphocyte reconstitution and thymic function in 80 patients given allogeneic peripheral blood stem cells after non-myeloablative conditioning. DESIGN AND METHODS: Median age at transplant was 57 years (range 10-71). Conditioning regimen consisted of 2 Gy total body irradiation (TBI) with (n=46) or without (n=20) added fludarabine, 4 Gy TBI with fludarabine (n=6), or cyclophosphamide plus fludarabine (n=8). Stem cell sources were unmanipulated (n=56), CD8-depleted (n=19), or CD34-selected (n=5) peripheral blood stem cells. Immune recovery was assessed by signal-joint T-cell receptor excision circle quantification and flow cytometry. RESULTS: Signal-joint T-cell receptor excision circle levels increased from day 100 to one and two years after transplantation in patients under 50 years of age (n=23; P=0.02 and P=0.04, respectively), and in those aged 51-60 years (n=35; P=0.17 and P=0.06, respectively), but not in patients aged over 60 (n=22; P=0.3 and P=0.3, respectively). Similarly, CD4(+)CD45RA(+) (naïve) T-cell counts increased from day 100 to one and two years after transplantation in patients aged 50 years and under 50 (P=0.002 and P=0.02, respectively), and in those aged 51-60 (P=0.4 and P=0.001, respectively), but less so in patients aged over 60 (P=0.3 and P=0.06, respectively). In multivariate analyses, older patient age (P<0.001), extensive chronic GVHD (P<0.001), and prior (resolved) extensive chronic graft-versus-host disease (P=0.008) were associated with low signal-joint T-cell receptor excision circle levels one year or more after HCT. CONCLUSIONS: In summary, our data suggest that thymic neo-generation of T cells occurred from day 100 onwards in patients under 60 while signal-joint T-cell receptor excision circle levels remained low for patients aged over 60. Further, chronic graft-versus-host disease had a dramatic impact on thymic function, as observed previously in patients given grafts after myeloablative conditioning.

Differentially abundant transcripts in PBMC of hospitalized geriatric patients with hip fracture compared to healthy aged controls.

The abundance of a selection of transcript species involved in inflammation, immunosenescence and stress response was compared between PBMC of 35 geriatric patients with hip fracture in acute phase (days 2-4 after hospitalization) or convalescence phase (days 7-10) and 28 healthy aged controls. Twenty-nine differentially abundant transcripts were identified in acute phase versus healthy ageing. Twelve of these transcripts remained differentially abundant in convalescence phase, and 22 were similarly differentially abundant in acute phase of geriatric infectious diseases. Seven of these 22 transcripts were previously identified as differentially abundant in PBMC of healthy aged versus healthy young controls, with further alteration for CD28, CD69, LCK, CTSD, HMOX1, and TNFRSF1A in acute phase after geriatric hip fracture and infectious diseases. The next question is whether these alterations are common to other geriatric diseases and/or preexist before the clinical onset of the diseases.

Serum IL-6 and IGF-1 improve clinical prediction of functional decline after hospitalization in older patients.

BACKGROUND AND AIMS: Although inflammatory and hormonal markers have been associated with further functional adverse outcomes in community- dwelling seniors, these markers have not been studied from this perspective in acutely ill older patients. This prospective study was designed to determine whether biological markers can improve the predictive value of a clinical screening tool to assess the risk of functional decline in hospitalized older patients. METHODS: Patients aged 75 years and over admitted for hip fracture, acute heart failure or infection (n=118) were recruited. The clinical screening tool SHERPA was filled in on admission, with concomitant measurement of interleukin-6 (IL-6), insulin-like growth factor 1 (IGF-1), C-reactive protein (CRP), white blood cells, urea, albumin, pre-albumin and total cholesterol. Functional decline was defined as a decrease of one point in the activities of daily living scale between pre-admission and 3-month post-discharge status. We compared the discrimination calibration of SHERPA vs SHERPA+, a logistic regression model including SHERPA and selected biomarkers. RESULTS: Three months after discharge, functional decline had occurred in 46 patients. IL-6 and IGF-1 were selected, since their levels were significantly different between decliners and non-decliners, and were included in the new logistic regression model SHERPA+. Areas under the ROC curve [95% CI] for functional decline prediction were 0.73 [0.63-0.81] for SHERPA vs 0.79 [0.69-0.86] for SHERPA+ (p=0.14). However, SHERPA+ was better calibrated, as the average predicted risk of functional decline within subgroups matched the proportion which actually underwent functional decline (Brier score=0.185). Since functional decline was higher in patients with hip fracture, the SHERPA+ model was challenged by including the diagnosis. Only SHERPA, IGF-1 and diagnosis were significantly associated with functional decline. CONCLUSIONS: Selected biological markers may marginally improve the clinical prediction of post-discharge functional decline in hospitalized patients, and may allow to stratify them appropriately. The predictive value of these biomarkers is not fully independent of disease status. Further studies are needed to confirm these results in a cohort representative of older patients admitted through the emergency department.

Evidence for neo-generation of T cells by the thymus after non-myeloablative conditioning.

BACKGROUND: Background and objective. We investigated immune recovery in 50 patients given either unmanipulated or CD8-depleted allogeneic peripheral blood stem cells after non-myeloablative conditioning. DESIGN AND METHODS: Fifty patients were randomized to receive either CD8-depleted (n=22) or non-manipulated (n=28) peripheral blood stem cells. The median patients age was 57 (range 36-69) years. The conditioning regimen consisted of 2 Gy total body irradiation with or without added fludarabine. Twenty patients received grafts from related donors, 14 from 10/10 HLA-allele matched unrelated donors, and 16 from HLA-mismatched unrelated donors. Graft-versus-host disease pro-phylaxis consisted of mycophenolate mofetil and cyclosporine. Immune recovery during the first year after hematopoietic cell transplantation was assessed by flow cytometry phenotyping, analyses of the diversity of the TCRBV repertoire, and quantification of signal-joint T-cell receptor excision circles (sjTREC). RESULTS: CD8-depletion of the graft reduced the recovery of CD8(+) T-cell counts in the first 6 months following transplantation (p<0.0001) but had no significant impact on the restoration of other T-cell subsets. Both sjTREC concentration and CD3(+) T-cell counts increased significantly between day 100 and 365 (p=0.010 and p=0.0488, respectively) demonstrating neo-production of T cells by the thymus. Factors associated with high sjTREC concentration 1 year after transplantation included an HLA-matched unrelated donor (p=0.029), a high content of T cells in the graft (p=0.002), and the absence of chronic graft-versus-host disease (p<0.0001). CONCLUSIONS: Our data suggest that while immune recovery is mainly driven by peripheral expansion of the graft-contained mature T cells during the first months after non-myeloablative transplantation, T-cell neo-generation by the thymus plays an important role in long term immune reconstitution in transplanted patients.

Angiogenic activity of human chorionic gonadotropin through LH receptor activation on endothelial and epithelial cells of the endometrium.

Successful embryo development requires an extensive endometrial angiogenesis in proximity of implantation site. The glycoprotein hCG is produced even before implantation by trophoblast in normal pregnancy. In this manuscript, we demonstrate an angiogenic effect of hCG in several in vivo (chick chorioallantoïc membrane, matrigel plug assay, aortic ring assay) and in vitro experimental models. In contrast, human placental lactogen (hPL) did not display angiogenic properties. LH/hCG receptor was detected in endothelial cells by reverse-transcriptase polymerase chain reaction (RT-PCR) and by Western blotting. In mice aortic ring assay, angiostimulation by hCG was abrogated by deletion of LH/hCG receptor (LuRKO mice). Use of recombinant hCG and anti-hCG antibody (Ab) further confirmed the specificity of this angiogenic activity. By using dibutyryl cAMP, adenylate cyclase, or protein kinase A inhibitors, we demonstrate that hCG-mediated angiogenesis involves adenylyl-cyclase-protein kinase A activation. Addition of hCG to endometrial epithelial epithelial cells, but not to cultured endothelial cells, stimulated vascular endothelial growth factor (VEGF). VEGF and hCG also displayed additive activities. Altogether, these data demonstrate that peritrophoblastic angiostimulation may result from a paracrine dialogue between trophoblast, epithelial, and endothelial cells through hCG and VEGF.

Oxytocin receptor pattern of expression in primary lung cancer and in normal human lung.

In order to assess if oxytocin- and vasopressin-induced mitogenic effects detected on small-cell lung carcinoma (SCLC) cell lines could be transposed on primary SCLC, the aim of the present work was to identify mediators of these mitogenic actions on primary tumours samples. This was addressed on normal human lung tissue, on SCLC and on non-SCLC (NSCLC). Herein, we observe, in normal human lung, that OTR is colocalized with vascular endothelial cells of the lung and is not expressed by lung cells of epithelial nature. We detected mRNA amplification of V1aR, V2R and of a V2R variant. We observed that 86% of SCLC biopsies analyzed expressed at least the OTR and that 71% expressed the OTR, the V1aR and the V2R altogether. Comparatively, 50% of NSCLC biopsies tested expressed at least the OTR and 32% expressed the OTR, the V1aR and the V2R altogether. The occurrence of the V1bR/V3R is of 28 and 18% for SCLC and NSCLC, respectively. Nevertheless, for the SCLC biopsies analyzed in this study, V1bR/V3R expression correlates, in all cases, with the expression of all the other neurohypophysial peptide receptors. Our results suggest that neurohypophysial peptide antagonists may offer promise as a potential new therapeutic modality for the treatment of lung cancer expressing at least one of the neurhypophysial peptide receptor subtypes.

Human endometrial leukemia inhibitory factor and interleukin-6: control of secretion by transforming growth factor-beta-related members.

OBJECTIVE(S): The implantation process is closely linked to the fundamental question of the tolerance of the maternal immune system. The main objective of this study was to investigate whether different members of the transforming growth factor-beta (TGF-beta) superfamily could intervene in the first steps of embryo implantation by modulating the secretion of proimplantatory leukemia inhibitory factor (LIF) and in the tolerance of the fetal graft by regulating proinflammatory interleukin (IL)-6 secretion by human endometrial epithelium (EEC) in vitro. METHODS: EEC were isolated from biopsies collected from 16 informed and consenting fertile women and were cultured for 72 h. Cytokine measurements (LIF and IL-6) were realized by ELISA. RESULTS: TGF-beta(1) (from 10(-12) to 10(-8)M), -beta(2), -beta(3) and activin A (10(-10) and 10(-8)M) increased LIF secretion by EEC cultures. Inhibin B (10(-10) and 10(-8)M) did not stimulate LIF production by human EEC. Contrastingly, TGF-beta(1) (from 10(-12) to 10(-8)M), -beta(2), -beta(3) and activin A (10(-10) and 10(-8)M) reduced IL-6 release by the same cells. Activin A at 10(-8) M also significantly reduced the stimulating effect of IL-1beta (10(-9)M) which is known to stimulate LIF production by EEC. Only the highest concentration of inhibin B (10(-8)M) reduced IL-6 secretion by EEC, but did not modulate IL-1beta-induced stimulation of IL-6 secretion. CONCLUSION(S): Besides their role in the control of the process of implantation and in the induction of embryonic mesoderm, different members of the TGF-beta superfamily may also contribute in the reproductive process by enhancing endometrial proimplantatory LIF secretion and reducing proinflammatory IL-6 release by EEC.

Oxytocin synthesis and oxytocin receptor expression by cell lines of human small cell carcinoma of the lung stimulate tumor growth through autocrine/paracrine signaling.

The objective of the present work was to investigate the existence of an oxytocin (OT)-mediated autocrine/paracrine signaling upon small cell carcinoma of the lung (SCCL) cell growth. In that view, OT receptor (OTR) expression, concomitant with OT synthesis and secretion, was evidenced on three different SCCL cell lines (DMS79, H146, and H345) and related to the vasopressin (VP) system. Specific OT, VP, OTR, V1a VP receptor (V1aR), and V1b/V3 VP receptor (V1bR/V3R) transcripts were identified by reverse transcription-PCR in all cell lines studied. Binding of 125I-(d(CH2)(5)(1), Tyr(Me)(2),Thr(4),Orn(8),Tyr(9)-NH2)-vasotocin (OVTA) was observed on all SCCL cell lines, with a K(d) (dissociation constant) ranging from 0.025-0.089 nM, depending on the cell line and the analytical method. Selectivity of 125I-OVTA binding was confirmed by displacement curves obtained with various OTR and VP receptor agonists and antagonists (OT, OVTA, L-371,257, VP, F180). Immunocytochemistry identified cellular OT and VP, and peptide secretion was measured in supernatants of SCCL cultures. [3H]Thymidine incorporations, applied on H345 cells, demonstrated a dose-dependent mitogenic effect of exogenous OT (1 and 100 nM) that was abolished by the OTR antagonist OVTA. A decrease of proliferation was also observed with OVTA alone, showing a functional mitogenic effect of tumor-derived OT. Taken together, these observations demonstrate the existence of a functional OT-mediated autocrine/paracrine signaling actively implicated in growth and development of SCCL tumors. Furthermore, these findings point to the potential of OT antagonists for development as therapeutic agents for the treatment of SCCL.

Persistent infection of human thymic epithelial cells by coxsackievirus B4.

Persistent replication of coxsackievirus B4 (CVB4) E2 (diabetogenic) and CVB4 JBV (nondiabetogenic) strains in thymic epithelial cell (TEC)-enriched cultures (>or=95%) was proved by detection of positive- and negative-strand viral RNA by reverse transcription-PCR in extracted RNA from cell cultures, VP1 capsid protein detection by immunofluorescence (IF) staining, and release of infectious particles up to 30 days after infection without obvious cytolysis. By double-IF staining, cytokeratin-containing cells were shown to be susceptible to CVB4. The persistence of CVB4 was associated with a significantly increased rate of TEC proliferation (up to 70%) after 20 days of culture and a significantly increased chronic production of immunoreactive interleukin-6 (IL-6), leukemia inhibitory factor, and granulocyte-macrophage colony-stimulating factor in supernatant after 3 days of culture. The CVB4 replication and the release of cytokines were not restricted to the CVB4 E2 diabetogenic strain and did not depend on the genetic background of the host; however, TEC were more responsive to CVB4 E2 than CVB4 JBV as far as the production of cytokines.