Interleukin-11 receptor subunit α-1 is required for maximal airway responsiveness to methacholine after acute exposure to ozone

Interleukin (IL)-11, a multifunctional cytokine, contributes to numerous biological processes, including adipogenesis, hematopoiesis, and inflammation. Asthma, a respiratory disease, is notably characterized by reversible airway obstruction, persistent lung inflammation, and airway hyperresponsiveness (AHR). Nasal insufflation of IL-11 causes AHR in wild-type mice while lung inflammation induced by antigen sensitization and challenge, which mimics features of atopic asthma in humans, is attenuated in mice genetically deficient in IL-11 receptor subunit α-1 (IL-11Rα1-deficient mice), a transmembrane receptor that is required conjointly with glycoprotein 130 to transduce IL-11 signaling. Nevertheless, the contribution of IL-11Rα1 to characteristics of nonatopic asthma is unknown. Thus, based on the aforementioned observations, we hypothesized that genetic deficiency of IL-11Rα1 attenuates lung inflammation and increases airway responsiveness after acute inhalation exposure to ozone (O3), a criteria pollutant and nonatopic asthma stimulus. Accordingly, 4 and/or 24 h after cessation of exposure to filtered room air or O3, we assessed lung inflammation and airway responsiveness in wild-type and IL-11Rα1-deficient mice. With the exception of bronchoalveolar lavage macrophages and adiponectin, which were significantly increased and decreased, respectively, in O3-exposed IL-11Rα1-deficient as compared with O3-exposed wild-type mice, no other genotype-related differences in lung inflammation indices that we quantified were observed in O3-exposed mice. However, airway responsiveness to acetyl-β-methylcholine chloride (methacholine) was significantly diminished in IL-11Rα1-deficient as compared with wild-type mice after O3 exposure. In conclusion, these results demonstrate that IL-11Rα1 minimally contributes to lung inflammation but is required for maximal airway responsiveness to methacholine in a mouse model of nonatopic asthma.

Expression of Interleukin-11 Receptor in CD38-positive Cells from Patients with Multiple Myeloma

Interleukin-11, a cytokine with multiple biological activities, has been shown to stimulate the proliferation and to support the long-term growth of human myeloma cell lines. Despite this, no expression of the interleukin-11alpha receptor has so far been demonstrated in myeloma cells. We have investigated the expression of interleukin-11alpha receptor and interleukin-11 at the level of mRNA and protein product in bone marrow mononuclear cells isolated from patients with multiple myeloma using reverse-transcriptase polymerase chain reaction and flow cytometry. The mRNA for interleukin-11alpha receptor and/or the corresponding protein were identified in 9 of 15 patients with multiple myeloma. In contrast, the interleukin-11 was not detected in any of the patients examined.

Effect of recombinant human interleukin-11 on expressions of interleukin-11 receptor α-chain and glycoprotein 130 in intestinal epithelium cell line-6 after neutron irradiation

AIM: To explore the effect of recombinant human interleukin-11 (rhIL-11) on the expressions of interleukin-11 receptor α-chain (IL-11Rα) and an additional signal transducer glycoprotein 130 (gp130) in intestinal epithelium cell line-6 (IEC-6) after neutron irradiation.

METHODS: Cultured IEC-6 cells were exposed to 4.0Gy neutron and treated with 100 ng/mL rhIL-11 12 h prior to or immediately after irradiation. The apoptosis and necrosis rates and expressions of IL-11Rα and gp130 were observed by flow cytometry, immunohistochemistry, Western blot and image analysis.

RESULTS: The apoptosis rate of IEC-6 cells was increased by irradiation at 6 h (P < 0.01), IL-11 stimulation resulted in a decreased apoptosis rate in irradiated IEC-6 cells (P < 0.05). In normal control IEC-6 cells, intense immunoreactivity of IL-11Rα was located within the cell membrane and cytoplasm. The level of IL-11Rα expression significantly decreased at 6 h after irradiation (P < 0.01) and restored at 24 h after irradiation. In IEC-6 cells treated with both radiation and rhIL-11, the level of IL-11Rα expression was higher than that of irradiated cells (P < 0.05). When it came to gp130 protein, it was located in the cytoplasm of IEC-6 cells. After irradiation, we found a progressive decrease in the expression of gp130 protein (P < 0.05) in 48 h post-radiation, while in rhIL-11-stimulated cells, it came back to normal level at 24 h after irradiation and decreased at 48 h, but was still higher than that of only irradiated cells (P < 0.05).

CONCLUSION: rhIL-11 can protect IEC-6 cells from neutron irradiation. The protective effect of rhIL-11 might be connected with its ability to up-regulate the expressions of specific ligand-binding subunit IL-11Rα and signal-transducing subunit gp130.

Expression of Interleukin 11 and Its Receptor and Their Prognostic Value in Human Breast Cancer

BACKGROUND

Recent experimental evidence has shown a potential role of interleukin (IL)-11 and its receptor in breast cancer development and progression. However, there is little clinical information to support this hypothesis. We examined the expression of IL-11 and its receptor in primary breast cancer tissue samples and correlated their level of expression with the clinical outcome.

METHODS

Primary breast cancer samples (n=109) and matched background tissue obtained from patients in the cohort (n=33) were processed for frozen section and RNA extraction. Frozen sections from matched tissues were immunostained with IL-11 and IL-11 receptor antibodies. Staining intensity was analyzed by computer image analysis. RNA was reverse-transcribed and quantified before analysis by quantitative polymerase chain reaction. Results were expressed as the number of transcripts (standardized by beta-actin). The data were compared with the clinical outcome of the disease.

RESULTS

The intensity of staining for both IL-11 and the IL-11 receptor was distinctly high in tumor samples (P<.01). The transcript level of IL-11 was significantly higher in node-positive tumor samples compared with node-negative samples (P=.02). Tumors with a poor prognostic index and poor histological grade showed a higher level of IL-11. A higher level of IL-11 was linked to poorer survival with Kaplan-Meier survival analysis.

CONCLUSIONS

IL-11 can be a predictor of poor prognosis in human breast cancer.

Interleukin-11, IL-11 receptorα and leukemia inhibitory factor are dysregulated in endometrium of infertile women with endometriosis during the implantation window

Interleukin (IL)-11 is essential for embryo implantation in the mouse and evidence suggests it has a role in implantation in humans. This study has evaluated immunoreactive IL-11, IL-11 receptor (R) alpha and leukemia inhibitory factor (LIF) in endometrium of infertile women with endometriosis (I/E) and normal fertile women (controls) during the implantation window. Endometrial biopsies from I/E (N = 7) were timed from the LH surge and were post-ovulatory days (POD) 5-10. Control biopsies (N = 8) from women were between days 19 and 24 of the menstrual cycle. Staining intensity of IL-11, IL-11Ralpha and LIF evaluated using semi-quantitative immunohistochemistry scores. Immunoreactive IL-11, IL-11Ralpha and LIF were present predominantly in glandular epithelium, while luminal epithelium showed patchy staining. All controls stained positively for IL-11, IL-11Ralpha and LIF in glandular epithelium. IL-11 and IL-11Ralpha staining was absent from glandular epithelium in cohorts of I/E. LIF staining intensity in glandular epithelium was significantly lower in I/E compared to controls. The results suggest that reduced endometrial IL-11 and/or LIF may contribute to infertility in some endometriotic women.

Expression of Interleukin-11 and Interleukin-11 receptor α in human colorectal adenocarcinoma; Immunohistochemical analyses and correlation with clinicopathological factors

AIM: There is strong evidence that interleukin-11 (IL-11) is involved in the regulation of tumor progression, cellular growth and differentiation. Recently, interleukin-11 receptor (IL-11R) has been detected on some cancer cells. In this study, we investigated the expression of IL-11 and IL-11R in colorectal adenocarcinoma.

METHODS: To elucidate the involvement of IL-11 and IL-11Rα in human intestinal adenocarcinomas, we examined 115 cases of surgically resected human colonic adenocarcinoma and 11 cases of adenoma by immunohistochemistry and Western blotting.

RESULTS: Among 115 cases of adenocarcinoma, 100 cases (87.0%) showed positive staining in the cytoplasm of carcinoma cells for the IL-11, and 87 cases (75.6%) were positive for the IL-11Rα. Six cases (54.5%) and four cases (36.4%) of 11 adenomas were positive for IL-11 and IL-11Rα, respectively. The expression of IL-11Rα correlated with the histological differentiation (P = 0.033503), the depth of tumor invasion (P = 0.006395), Dukes’ classification (P = 0.015648) and lymphatic invasion (P = 0.003865). However, the expression of IL-11Rα was not correlated with the venous invasion and the presence of lymph node metastasis. The expression of IL-11 was not correlated with any clinicopathological factors. In Western blot analysis, two human colorectal carcinoma cell lines and four tissues of surgically resected human carcinoma expressed both IL-11 and IL-11Rα proteins.

CONCLUSION: IL-11 and IL-11Rα are highly expressed in human colorectal adenocarcinoma and the IL-11Rα expression is correlated with clinicopathological factors. These findings suggest that the expression of IL-11Rα is an important factor for the invasion of human colorectal adenocarcinoma.

Gene expression profile of cytokines and chemokines in microdissected primary Hodgkin and Reed-Sternberg (HRS) cells: high expression of interleukin-11 receptor alpha

We microdissected Hodgkin and Reed-Sternberg (HRS) cells from 14 Hodgkin's lymphoma tissue samples (nodular sclerosis = 5; mixed cellularity = 9), and after isolation and amplification of mRNA, analyzed the expression profile of 140 genes of chemokines, cytokines and their receptors by cDNA microarray methods. We also compared the profile with those of germinal center (GC) cells in reactive lymphadenitis. Unsupervised clustering revealed a relatively homogeneous expression profile in HRS cells. HRS cells tended to express mainly Th2 T cell-associated molecules rather than those of Th1, compared with GC cells. Interleukin-11 receptor alpha (IL-11Ralpha), a previously unknown HRS cell-specific gene, was detected in addition to known genes. Immunohistochemical staining confirmed the expression of IL-11Ralpha at the protein level. In contrast, only few cases were positive for IL-11Ralpha in B cell lymphoma, diffuse large cell lymphoma and follicular lymphoma. This is the first analysis report of tissue HRS cells with cDNA microarray technique.

Interleukin-11 receptor signaling is required for normal bone remodeling

IL-6 and -11 regulate bone turnover and have been implicated in estrogen deficiency-related bone loss. In this study, deletion of IL-11 signaling, but not that of IL-6, suppressed osteoclast differentiation, resulting in high trabecular bone volume and reduced bone formation. Furthermore, IL-11 signaling was not required for the effects of estradiol or estrogen deficiency on the mouse skeleton.

INTRODUCTION

Interleukin (IL)-6 and -11 stimulate osteoclastogenesis and bone formation in vitro and have been implicated in bone loss in estrogen deficiency. Because of their common use of the gp130 co-receptor signaling subunit, the roles of these two cytokines are linked, and each may compensate for the absence of the other to maintain trabecular bone volume and bone cell differentiation.

MATERIALS AND METHODS

To determine the interactions in bone between IL-11 and IL-6 in vivo and whether IL-11 is required for normal bone turnover, we examined the bone phenotype of mature male and female IL-11 receptor knockout mice (IL-11Ralpha1-/-) and compared with the bone phenotype of IL-6-/- mice and mice lacking both IL-6 and IL-11Ralpha. To determine whether IL-11 is required for the effects of estrogen on trabecular bone, mature IL-11Ralpha1-/- mice were ovariectomized and treated with estradiol.

RESULTS

In both male and female IL-11Ralpha1-/- mice, trabecular bone volume was significantly higher than that of wildtype controls. This was associated with low bone resorption and low bone formation, and the low osteoclast number generated by IL-11Ralpha1-/- precursors was reproduced in ex vivo cultures, whereas elevated osteoblast generation was not. Neither trabecular bone volume nor bone turnover was altered in IL-6-/- mice, and compound IL-6-/- :IL-11Ralpha1-/- mice showed an identical bone phenotype to IL-11Ralpha1-/- mice. The responses of IL-11Ralpha1-/- mice to ovariectomy and estradiol treatment were the same as those observed in wildtype mice.

CONCLUSIONS

IL-11 signaling is clearly required for normal bone turnover and normal trabecular bone mass, yet not for the effects of estradiol or estrogen deficiency on the skeleton. In the absence of IL-11Ralpha, increased trabecular bone mass seems to result from a cell lineage-autonomous reduction in osteoclast differentiation, suggesting a direct effect of IL-11 on osteoclast precursors. The effects of IL-11Ralpha deletion on the skeleton are not mediated or compensated for by changes in IL-6 signaling.

Interleukin-11 signaling is required for the differentiation of natural killer cells at the maternal-fetal interface

Interleukin-11 (IL-11) is a multifunctional hematopoietic growth factor that has been implicated in the control of reproduction. Studies on IL-11 receptor-alpha (IL-11R alpha)-deficient mice showed that female mice are infertile due to defective decidualization. In this report, we evaluated the development of decidual cells, immune cells, and the vasculature associated with the implantation site of IL-11R alpha-deficient mice; with the aim of better understanding the nature of the fertility defect. Messenger RNAs for decidual differentiation, such as decidual prolactin-related protein and prolactin-like protein-J are expressed in the IL-11R alpha mutant. However, the number of decidual cells expressing these genes is decreased in the mutant compared with the wild-type control. Although, trophoblast cells differentiate and express placental lactogen-I in the IL-11R alpha-deficient uterine environment, they fail to progress and expand in number. Defects in the organization of the decidual vasculature were also apparent in the IL-11R alpha mutant uterus. The most dramatic effect of IL-11 signaling was on the hematopoietic environment of the uterine decidua. Differentiated/perforin-expressing uterine natural killer (NK) cells were virtually absent from implantation sites of IL-11R alpha mutant mice. NK cell precursors were capable of homing to the IL-11R alpha-deficient uterus and a known regulator of NK cell differentiation; IL-15 was expressed in the IL-11R alpha mutant uterus. Splenic NK cells from IL-11R alpha mutant mice were also able to respond to IL-15 in vitro. Thus, the defect in NK precursor cell maturation was not intrinsic to the NK precursor cells but was dependent upon the tissue environment. In summary, IL-11 signaling is required for decidual-specific maturation of NK cells.

IL-11 receptor alpha in the pathogenesis of IL-13-induced inflammation and remodeling

IL-13 is a major stimulator of inflammation and tissue remodeling at sites of Th2 inflammation. In Th2-dominant inflammatory disorders such as asthma, IL-11 is simultaneously induced. However, the relationship(s) between IL-11 and IL-13 in these responses has not been defined, and the role(s) of IL-11 in the genesis of the tissue effects of IL-13 has not been evaluated. We hypothesized that IL-11, signaling via the IL-11Ralpha-gp130 receptor complex, plays a key role in IL-13-induced tissue responses. To test this hypothesis we compared the expression of IL-11, IL-11Ralpha, and gp130 in lungs from wild-type mice and transgenic mice in which IL-13 was overexpressed in a lung-specific fashion. We simultaneously characterized the effects of a null mutation of IL-11Ralpha on the tissue effects of transgenic IL-13. These studies demonstrate that IL-13 is a potent stimulator of IL-11 and IL-11Ralpha. They also demonstrate that IL-13 is a potent stimulator of inflammation, fibrosis, hyaluronic acid accumulation, myofibroblast accumulation, alveolar remodeling, mucus metaplasia, and respiratory failure and death in mice with wild-type IL-11Ralpha loci and that these alterations are ameliorated in the absence of IL-11Ralpha. Lastly, they provide insight into the mechanisms of these processes by demonstrating that IL-13 stimulates CC chemokines, matrix metalloproteinases, mucin genes, and gob-5 and stimulates and activates TGF-beta1 via IL-11Ralpha-dependent pathways. When viewed in combination, these studies demonstrate that IL-11Ralpha plays a key role in the pathogenesis of IL-13-induced inflammation and remodeling.

Aberrant regulation of interleukin-12 receptor beta2 chain on type 1 cytokine-stimulated T lymphocytes in type 1 diabetes

An aberrant mitogen-induced polarization of peripheral blood T cells has been associated with type 1 diabetes (T1D). We studied, in T1D, type 1 and 2 cytokine-induced expression of the interleukin-12 receptor beta2 chain (IL-12Rbeta2 chain), which plays a critical role in regulating T-cell polarization. Peripheral blood lymphocytes from children with newly diagnosed T1D (n=10; mean age 10 years), from children with longstanding T1D (n=8; mean age 12.9 years) and from healthy children (n=15; mean age 11.5 years) were stimulated with phytohaemagglutinin (PHA) in a type 1 (IL-12 and anti-IL-4) or a type 2 (IL-4 and anti-IL-12) cytokine environment. Secretion of interferon-gamma (IFN-gamma), IL-5 and IL-13, as detected by enzyme-linked immunosorbent assay (ELISA), and expression of the IL-12Rbeta2 chain on CD4 and CD8 cells by flow cytometry, were analysed. Children with newly diagnosed and longstanding T1D had lower expression levels of the IL-12Rbeta2 chain on IL-12Rbeta2 chain-positive CD4 T cells (for a type 1 or a type 2 cytokine environment: P=0.01 and P=0.002 or P=0.02 and P=0.01, respectively) and on IL-12Rbeta2 chain-positive CD8 T cells (for a type 1 or a type 2 cytokine environment: P=0.007 and P=0.0007 or P=0.003 and P=0.01, respectively) when compared to healthy children. A decreased percentage of IL-12Rbeta2 chain-expressing CD4 T cells (P=0.07 and P=0.03) and CD8 T cells (P=0.004 and P=0.01) and increased secretion of IL-13 (P=0.006 and P=0.04) in a type 1 cytokine environment was seen in both groups of patients. Peripheral blood T cells from patients with both newly diagnosed and longstanding T1D showed poor polarization towards type 1 cells.

The production of interleukin-11 and decidualization are compromised in endometrial stromal cells derived from patients with infertility

IL-11 signaling is critical for decidualization of the endometrial stroma in early pregnancy in the mouse. In this study, we investigate the function of IL-11 signaling in cAMP-induced decidualization of human endometrial stromal cells. We show that treatment of endometrial stromal cells with 8-bromo-cAMP (8-Br-cAMP) results in an increase in the levels of secreted IL-11, whereas levels of cell surface IL-11 receptor alpha are similar with or without 8-Br-cAMP treatment. The production of IL-11 correlates with the production of molecular markers of decidualization, prolactin and IGF-binding protein-1. The expression of these markers is inhibited when IL-11 signaling is specifically blocked in decidualizing endometrial stromal cells by the IL-11 antagonist W147A. We demonstrate that 8-Br-cAMP-induced endometrial stromal cells derived from patients with primary infertility produce lower levels of prolactin, IGF-binding protein-1, and IL-11 than cells derived from fertile women. Our results suggest that IL-11 expression is critically important during decidualization in the human endometrium, and that aberrant regulation of endometrial IL-11 production may be associated with some types of infertility.

Characterization and expression analysis of the chicken interleukin-11 receptor alpha chain

Interleukin-11 (IL-11) is a multifunctional cytokine involved in various pathways in blood cells, their precursors and many other cell types in vitro and in vivo. The effects of IL-11 are largely mediated by the IL-11 receptor alpha-chain (IL-11Ralpha). In this study, a putative cDNA sequence encoding the 414 amino acid propeptide of chicken IL-11R (chIL-11R) was identified. The predicted 414 amino acid sequence showed 42-43% sequence identity with mammalian homologues. In a domain search of the molecule, two fibronectin (FN) type-III domains were identified in the C- terminal portion. On comparison with mammalian IL-11R, 4 conserved cysteine residues and a WSXWS motif were observed within the FN type-III domains. Expression analysis revealed that chIL-11Ralpha is strongly expressed in brain, heart, lung, liver, glandular stomach, kidney, the immature testis, ovary and chicken blastodermal cells (CBCs) after 1-day-cultivation. These findings strongly indicate that the identified chicken cDNA sequence encodes chIL-11R alpha-chain homologue.

Expression of interleukin-11 receptor α and interleukin-11 protein in the endometrium of normal fertile women and women with recurrent miscarriage

Interleukin-11 (IL-11) is a member of the IL-6 family of cytokines. Previous studies have suggested that IL-11 may play a role in human endometrial function. In this study, we have used immunocytochemistry to compare endometrial IL-11Ralpha and IL-11 expression in precisely timed peri-implantation biopsies from 9 normal fertile women and 16 recurrent miscarriage (RM) women. Immunocytochemistry was semi-quantified by obtaining an H-score value, which showed increased expression of both IL-11 and IL-11Ralpha in epithelial cells compared to stromal cells in all biopsies. There was a significant (P<0.01) reduction in epithelial cell IL-11, but not stromal cell IL-11, expression in endometrium from RM women compared to normal fertile women. There were no significant differences in expression of IL-11Ralpha protein in both stromal and epithelial cells in endometrium from the two groups of women. This work shows the presence of IL-11 and IL-11Ralpha within the endometrium of RM women during the peri-implantation period. The decreased expression of IL-11 in epithelial endometrium in RM women suggests that this cytokine may play a role in preventing miscarriage.

Uterine extracellular matrix components are altered during defective decidualization in interleukin-11 receptor alpha deficient mice

BACKGROUND

Implantation of the embryo and successful pregnancy are dependent on the differentiation of endometrial stromal cells into decidual cells. Female interleukin-11 receptor alpha (IL-11Ralpha) deficient mice are infertile due to disrupted decidualization, suggesting a critical role for IL-11 and its target genes in implantation. The molecular targets of IL-11 in the uterus are unknown, but it is likely that IL-11 signaling modifies the expression of other genes important in decidualization. This study aimed to identify genes regulated by IL-11 during decidualization in mouse uterus, and to examine their expression and localization as an indication of functional significance during early pregnancy.

METHODS

Decidualization was artificially induced in pseudopregnant wild type (IL11Ra+/+) and IL-11Ralpha deficient (IL11Ra-/-) littermates by oil injection into the uterine lumen, and gene expression analyzed by NIA 15K cDNA microarray analysis at subsequent time points. Quantitative real-time RT-PCR was used as an alternative mRNA quantitation method and the expression and cellular localization of the protein products was examined by immunohistochemistry.

RESULTS

Among 15,247 DNA probes, 13 showed increased and 4 decreased expression in IL11Ra-/- uterus at 48 h of decidualization. These included 4 genes encoding extracellular matrix proteins; collagen III alpha1, secreted acidic cysteine-rich glycoprotein (SPARC), biglycan and nidogen-1 (entactin). Immunohistochemistry confirmed increased collagen III and biglycan protein expression in IL11Ra-/- uterus at this time. In both IL11Ra-/- and wild type uterus, collagen III and biglycan were primarily localized to the outer connective tissue and smooth muscle cells of the myometrium, with diffuse staining in the cytoplasm of decidualized stromal cells.

CONCLUSION

These data suggest that IL-11 regulates changes in the uterine extracellular matrix that are necessary for decidualization.

Interleukin-11 expression: its significance in eutopic and ectopic human implantation

Embryo implantation and subsequent decidualization, trophoblast invasion and formation of a functional placenta are crucial for establishment and maintenance of pregnancy. Interleukin-11 signalling has been shown to be obligatory for adequate decidualization and trophoblast invasion in mice. Defects in IL-11 signalling in mice result in trophoblast over-invasion and fetal loss. The pathological situation of human tubal pregnancy resembles that of IL-11Ralpha(-/-) mice concerning these symptoms. As our interest is focused on the human early pregnancy, we compared IL-11 expression at the implantation site of ectopic tubal pregnancy (EP) to 1st and 2nd trimester of normal intrauterine pregnancies (IP), and to the normal cycling endometrium. The mRNA expression of IL-11 and IL-11Ralpha was analysed by semiquantitative RT-PCR. Protein expression was detected by western blotting and immunohistochemistry. IL-11Ralpha is expressed constitutively in all tissue specimens analysed. IL-11 is expressed predominantly during follicular and early luteal phase of the menstrual cycle. In IP, IL-11 expression peaks during the 1st trimester and declines from the beginning of the 2nd trimester onwards. In tubal abortions, IL-11 expression is reduced in comparison to vital EP and IP. Cultured primary endometrial and decidual epithelial cells were analysed for hormonal regulation of IL-11 by enzyme-linked immunosorbent assay and RT-PCR. IL-11 is up-regulated by estrogen and down-regulated by progesterone. Overall, our results indicate that in humans, IL-11 signalling is significantly involved in regulation of trophoblast invasion. In the case of tubal abortion, inadequate IL-11 signalling may therefore result in dysregulation of trophoblast invasion.

Immunologic variables in acute mania of bipolar disorder

Macrophages, lymphocytes and their products, may be involved in the pathophysiology of psychiatric disorders. The cell-mediated immune activation response of manic patients during pre-medication and medication stages remains unclear. The purpose of this case-control study was to investigate the plasma levels of immunologic variables, including interleukin (IL)-1 receptor antagonist (IL-1RA), soluble CD 4 (sCD4) and sCD8, and TH1 (interferon [IFN]-gamma and IL-2) and TH2 (IL-4 and IL-10) cytokines in patients with pre-medicated, medicated bipolar mania. The study subjects, aged 16-44 years, were physically healthy patients with Young Mania Rating Scale (YMRS) scores > or =26, and normal controls, aged 19-40 years, were matched for sex. The immune variables were measured in acute mania and in consequent remission (YMRS scores < or =12) among bipolar patients. The plasma levels of IL-1RA, sCD4, and sCD8 were found significantly increased in pre-medicated acute manic patients as compared to normal controls. But only IL-1RA and sCD8 were found different in remitted bipolar patients as compared to normal controls. For TH1 cytokines, culture supernatant level of IFN-gamma was found significantly lower in manic patients of both acute and remission stages as compared to normal controls. No significant difference was found in IL-2 level in pre-medicated acute manic patients compared to controls. For TH2 cytokines, no significant differences in IL-4 and IL-10 levels were observed. We showed that cell-mediated immune response was activated in patients with bipolar disorder during the pre-medication, medication, and the remission stages. Our study findings suggest that the immune-modulation in patients with bipolar disorder may be abnormal.

Functional Expression of the Interleukin-11 Receptor α-Chain and Evidence of Antiapoptotic Effects in Human Colonic Epithelial Cells

A tissue-protective effect of interleukin-11 (IL-11) for the intestinal mucosa has been postulated from animal models of inflammatory bowel disease (IBD). Despite the fact that the clinical usefulness of the anti-inflammatory effects of this cytokine is presently investigated in patients with IBD, there are no data available regarding the target cells of IL-11 action and the mechanisms of tissue protection within the human colonic mucosa. IL-11 responsiveness is restricted to cells that express the interleukin-11 receptor alpha-chain (IL-11Ralpha) and an additional signal-transducing subunit (gp130). In this study, we identified the target cells for IL-11 within the human colon with a new IL-11Ralpha monoclonal antibody and investigated the functional expression of the receptor and downstream effects of IL-11-induced signaling. Immunohistochemistry revealed expression of the IL-11Ralpha selectively on colonic epithelial cells. HT-29 and colonic epithelial cells (CEC) constitutively expressed IL-11Ralpha mRNA and protein. Co-expression of the signal-transducing subunit gp130 was also demonstrated. IL-11 induced signaling through triggering activation of the Jak-STAT pathway without inducing anti-inflammatory or proliferative effects in colonic epithelial cells. However, IL-11 stimulation resulted in a dose-dependent tyrosine phosphorylation of Akt, a decreased activation of caspase-9, and a reduced induction of apoptosis in cultured CEC. In HLA-B27 transgenic rats treated with IL-11, a reduction of apoptotic cell numbers was found. This study demonstrates functional expression of the IL-11Ralpha restricted on CEC within the human colonic mucosa. IL-11 induced signaling through triggering activation of the Jak-STAT pathway, without inducing anti-inflammatory or proliferative effects. The beneficial effects of IL-11 therapy are likely to be mediated by CEC via activation of the Akt-survival pathway, mediating antiapoptotic effects to support mucosal integrity.

Combinatorial Screenings in Patients

Direct screening of combinatorial peptide libraries in patients may allow the identification of ligands that target biochemical differences in the endothelium of blood vessels. In a screening performed in a patient, we selected and isolated a mimic motif of interleukin 11 (IL-11) from prostate biopsies after an i.v. administration of a phage display peptide library. We also demonstrated that the IL-11 phage mimic (displaying the cyclic nonapeptide CGRRAGGSC) bound specifically to a corresponding IL-11 receptor (IL-11Ralpha). Here we show that IL-11Ralpha is a potential target for intervention in human prostate cancer through morphological and functional analyses. First, a comprehensive serial immunohistochemical analysis of primary and metastatic prostate cancer samples showed increased stage-specific expression of IL-11Ralpha during disease progression. Second, a proapoptotic peptide was specifically targeted and internalized through this functional IL-11Ralpha-based ligand-receptor pair: treatment of prostate cancer cells in vitro with a proapoptotic peptide guided by the CGRRAGGSC peptide to the IL-11Ralpha resulted in dose-dependent apoptosis. Together, these data indicate that the IL-11Ralpha is a candidate target for translational clinical trials against advanced and metastatic prostate cancer. Moreover, our results illustrate the ability of direct combinatorial screening systems in cancer patients for identification of relevant targets in the context of human disease.

Determinants of iodothyronine deiodinase activities in rodent uterus

The deiodinase types 2 and 3 (D2, D3), which convert T4 to active and inactive metabolites, respectively, are expressed in the rodent uterus and highly induced during pregnancy. To examine the factors regulating the expression of these enzymes in this tissue, we studied D2 and D3 activity in pregnant rats, in pseudopregnant rats before and after the induction of artificial decidualization, and in ovariectomized rats treated with 17beta-estradiol (E2) and/or progesterone (P). Our results demonstrate that induction of D3 activity begins immediately after implantation and increases markedly over the next 72 h. A similar time course and magnitude of D3 induction is noted in the artificially decidualized uterus in pseudopregnant rats, whereas only minimal increases in activity are observed in the nondecidualized control uterine horns in the same animal. In contrast, D2 activity is not induced by a decidualization stimulus. In spontaneously cycling female rats, both D2 and D3 were observed to be 3- to 8-fold higher in proestrus, compared with diestrus. Furthermore, levels of D2 and D3 activity were greatly increased in ovariectomized rats given E2 and P in various combinations. D2 activity was stimulated primarily by E2, whereas E2 and P acted synergistically to increase D3 activity. These results demonstrate that E2 and P regulate thyroid hormone metabolism in the uterus, and that the implantation process is a potent stimulus for the induction of D3 activity in this organ. Such precise and profound changes in deiodinase expression are likely to play important physiological roles in fetal development and may influence uterine function.

Characterization of a potent human interleukin-11 agonist

Human interleukin-11 (hIL-11) is a multi-potential cytokine that is involved in numerous biological activities, such as haematopoiesis, osteoclastogenesis, neurogenesis and female fertility, and also displays anti-inflammatory properties. IL-11 is used clinically to treat chemotherapy-induced thrombocytopenia. Because of its broad spectrum of action, improved IL-11 agonists, as well as IL-11 antagonists, could be of interest for numerous clinical applications. IL-11 signalling is dependent on the formation of a tripartite ligand-receptor complex consisting of IL-11, the IL-11R (IL-11 receptor) alpha subunit (responsible for the specificity of the interaction) and gp130 (glycoprotein 130) receptor beta subunit (responsible for signal transduction). The interaction between IL-11 and IL-11Ralpha subunit occurs at its recently assigned site I. We have designed an IL-11 mutein whose hydrophobicity at site I has been increased. The mutein has been characterized in terms of structure, affinity, specificity and bioactivity. Electrophoretic analysis, gel filtration, IR spectroscopy and CD indicate that this new protein is more compact than wild-type IL-11. It binds to IL-11Ralpha with a three-fold-enhanced affinity, and retains the ability to recruit gp130 through site II. However, analysis of its biological activity revealed a complex pattern: although this mutein is 60-400-fold more active than wild-type IL-11 on the proliferation of 7TD1 murine hybridoma cell, it is less active than IL-11 on the proliferation of B9 cells, another murine hybridoma cell line. The results are interpreted on the basis of an IL-11 conformational change induced by the mutations, and the preferential use by the mutein of another unknown transducing receptor chain.

Functional characterization of W147A: a high-affinity interleukin-11 antagonist

IL-11 is a member of the gp130 family of cytokines, which signal via assembly of multisubunit receptor complexes containing at least one molecule of the transmembrane signaling receptor gp130. IL-11 forms a high-affinity complex, thereby inducing gp130-dependent signaling. Previous studies have identified three distinct receptor binding sites, I, II, and III, crucial for the binding of murine IL-11 (mIL-11) to both the IL-11R and gp130. In this study, we have further characterized the role of the mIL-11 site III mutant W147A. We show that W147A is a high-affinity specific antagonist of mIL-11-mediated signaling in gp130/IL-11R-transfected Ba/F3 cells. The antagonistic action of W147A is due to its ability to competitively disrupt multimeric gp130/IL-11R signaling complex formation. We also show that W147A inhibits IL-11-mediated signaling in primary human endometrial cells, thus demonstrating the potential utility of W147A in suppressing IL-11 responses in vivo.

Interleukin-11-induced heat shock protein 25 confers intestinal epithelial-specific cytoprotection from oxidant stress

BACKGROUND & AIMS

The mechanisms of interleukin-11 (IL-11) cytoprotection in intestinal epithelial injury are largely unknown. IL-11 protects barrier integrity during oxidant stress, a common endpoint of numerous types of intestinal injury including ischemia and immune-mediated inflammation. Because heat shock proteins (hsp) are cytoprotective in intestinal epithelia, we hypothesized that IL-11-conferred cytoprotection is mediated by inducible hsps.

METHODS

IL-11 receptor (IL-11R) activation was determined using phospho-specific antibodies to STAT3. IL-11 induction of hsp72 and hsp25 was determined by immunoblot in IEC-18 crypt and young adult mouse colon colonic epithelial cells. Epithelial resistance to oxidant injury by monochloramine was determined by (51)Cr release. Stable hsp anti-sense IEC-18 cell clones were obtained by electroporation and hygromycin B selection. The IL-11 effect on hsp25 distribution was characterized by analysis of Triton x-100 insoluble fractions, 2-D isoelectric focusing gels, and confocal microscopy.

RESULTS

IL-11R signaling was detected in all cells under study. IL-11 induces hsp25 in an intestinal epithelial-specific manner that significantly preserves cellular viability in the presence of monochloramine. This effect was significantly reversed in intestinal epithelia stably expressing anti-sense to hsp25. IL-11 induced a shift of hsp25 to Triton x-100 insoluble fractions containing cytoskeletal elements, which was not associated with altered hsp25 phosphorylation. The shift was not paralleled by increased hsp25 co-localization with F-actin by confocal microscopy.

CONCLUSIONS

The induction of hsp25 by IL-11 confers epithelial-specific cytoprotection that is independent of phosphorylation-dependent co-localization of hsp25 to F-actin, thereby contributing to the protective effects of IL-11 in models of intestinal epithelial injury.

IL-11 and IL-11Ralpha immunolocalisation at primate implantation sites supports a role for IL-11 in placentation and fetal development

Embryo implantation, endometrial stromal cell decidualization and formation of a functional placenta are critical processes in the establishment and maintenance of pregnancy. Interleukin (IL)-11 signalling is essential for adequate decidualization in the mouse uterus and IL-11 promotes decidualization in the human. IL-11 action is mediated via binding to the specific IL-11 receptor alpha (IL-11Ralpha). The present study examined immunoreactive IL-11 and IL-11Ralpha in cycling rhesus monkey endometrium, at implantation sites in cynomolgus and rhesus monkeys and in human first trimester decidua and defined distinct spatial and temporal patterns. In cycling rhesus monkey endometrium, IL-11 and IL-11Ralpha increased in both basalis and functionalis regions during the secretory compared with the proliferative phase, with changing cellular locations in luminal and glandular epithelium and stroma. The patterns were similar overall to those previously described in human endometrium. Differences were seen in immunostaining during implantation in cynomologus and rhesus monkey. In the cynomolgus, very little staining for IL-11 or IL-11Ralpha was seen in syncytio- and cyto-trophoblast cells in the villi between days 12 and 150 of pregnancy although there was moderate staining in cytotrophoblast in the shell between days 12 and 17 and in subpopulations of cytotrophoblast cells invading the arteries at day 17. By contrast in the rhesus monkey between days 24 and 35 of pregnancy and in human first trimester placenta, cyto- and syncytio-trophoblast in the villi but not cytotrophoblast in the shell were positively stained. The most intense staining for both IL-11 and IL-11Ralpha was present within the decidua in the maternal component of implantation sites in all three primates but moderate staining was also present in maternal vascular smooth muscle and glands perivascular cells and epithelial plaques. These results are consistent with a role for IL-11 both during decidualization and placentation in primates.

Expression and function of interleukin-11 and its receptor alpha in the human endometrium

The interleukin-11 (IL-11) receptor alpha has an important function in decidualization of mouse endometrial stroma but the function of IL-11 and its receptor in the human endometrium remains unknown. The mRNA for IL-11 and its receptor alpha in human endometrial tissue samples were analysed by semi-quantitative RT-PCR and RNase protection assays respectively. The proteins were detected in frozen endometrial tissue samples by immunofluorescence. The effect of heparin-binding epidermal growth factor (HB-EGF) on secretion of IL-11 by cultured endometrial stromal cells was assessed by enzyme-linked immunosorbent assay. The proliferative potential of IL-11 in endometrial stromal cells was assessed by [(3)H]thymidine uptake. IL-11 and its receptor alpha mRNAs and proteins were detected in the endometrium throughout the cycle. Distinct patterns of localization of the ligand and receptor were observed. HB-EGF induced IL-11 secretion by cultured stromal cells, and IL-11 induced [(3)H]thymidine uptake by these cells. Our data suggest that IL-11-receptor interactions may perform different functions in the human endometrium at different stages of the cycle, and that secretion of IL-11 is modulated by local growth factors.

Expression of interleukin (IL)-11 receptor by the human endometrium in vivo and effects of IL-11, IL-6 and LIF on the production of MMP and cytokines by human endometrial cells in vitro

Interleukin (IL)-6, leukaemia inhibitory factor (LIF) and IL-11 belong to the same family of cytokines whose receptors utilize gp130 as the signalling molecule. We have investigated the expression of the IL-11 receptor, IL-11Ralpha, protein in the human endometrium in vivo and the effects of IL-6, LIF and IL-11 on the production of metalloproteinases (MMPs) and cytokines by cultured endometrial epithelial and stromal cells. Immunostaining showed that IL-11Ralpha was expressed in both epithelial and stromal cells, with epithelial staining being more intense than stromal staining and little variation in staining in either compartment throughout the cycle. Incubation of both stromal and epithelial cells with IL-6, LIF and IL-11 had no effect on MMP-2, -7, -9, transforming growth factor (TGF)beta or IL-1beta production or cell growth. IL-6 and LIF also had no effect on tumour necrosis factor (TNF)alpha production, but IL-11 caused a dose-dependent decrease in TNFalpha production by epithelial cells. IL-6 receptor, LIF receptor and gp130 were all expressed by cultured stromal and epithelial cells, showing that the lack of effect is not due to lack of expression of the receptor components. The results show that although IL-6, LIF and IL-11 signal through the same molecule, they may have different effects in endometrial cells, suggesting the activation of different signalling pathways, which may ultimately be important in the control of endometrial function.

Cytokine receptor repertoire and cytokine responsiveness of Ho(dull)/Rh(dull) stem cells with differing potentials for G1/S phase progression

OBJECTIVE

Subsetting of Hoechst 33342 dull (Ho(dull)) hematopoietic stem cells on the basis of rhodamine 123 (Rh) efflux utilizing an improved dual-dye efflux strategy resolves Ho(dull)/Rh(dull) stem cell subsets that differ with regard to their rate of recruitment and progression through the cell cycle upon exposure to cytokines.

MATERIALS AND METHODS

Murine bone marrow cells were isolated by negative immunomagnetic selection using lineage-directed antibodies followed by Ho and Rh staining using a dual-dye efflux method.

RESULTS

Ho(dull)/Rh(dull) stem cells that efflux Rh more efficiently (R1) exhibit a 4- to 8-hour delay in progression to S phase when stimulated by interleukin-3 (IL-3), IL-6, IL-11, and stem cell factor (SCF) compared to Ho(dull)/Rh(medium) stem cells, which retain low levels of Rh (R2). R1 and R2 cells show a hierarchical entry into S phase upon exposure to any or all of these cytokines. The R1 subset contains proportionately more high proliferative potential colony-forming cells than the R2 subset, but equivalent levels of engraftable stem cells at 3 and 8 weeks after competitive transplantation. Both R1 and R2 cells express c-kit, IL-3R, and IL-11R, whereas IL-6R and c-fms are only expressed by R1 or R2 cells, respectively. Cytokine stimulation of R1 and R2 cells induced cell cycle progression with elevated or induced expression of c-kit, c-fms, IL-2R, and IL-6R.

CONCLUSION

These studies indicate that primitive marrow stem cells can be further subsetted by degree of Rh staining to reveal important functional phenotypic differences between cells with different levels of Rh staining.

Defective production of interleukin-11 by decidua and chorionic villi in human anembryonic pregnancy

Previous study demonstrated that IL-11 receptor alpha knockout female mice (IL-11Ralpha(-/-)) were phenotypically normal but infertile due to defective decidualization. However, the role of IL-11 signaling in human reproduction remains unclear. This study examined the expression of IL-11, IL-11Ralpha, and signal transduction factor glycoprotein 130 in different phases of endometrium (six in proliferative phase and four in secretory phase), and the decidua and villi of normal pregnancy (NP; n = 25) and anembryonic pregnancy (AP; n = 25) in the first trimester (gestational week 7-9). RT-PCR showed IL-11, IL-11Ralpha, and glycoprotein 130 mRNA expression in all samples, except the absence of IL-11 signal in the unstimulated MRC-5 cell and the proliferative phase endometrium. Real-time quantitative PCR showed that the relative level of IL-11Ralpha mRNA was not significantly different among proliferative phase endometrium (relative level; mean +/- SEM, 1.4 +/- 0.5), secretory phase endometrium (1.3 +/- 0.1), or decidua from NP or AP (1.7 +/- 0.3 and 1.9 +/- 0.4, respectively), but was significantly greater in chorionic villi either from NP or AP (7.6 +/- 1.3 and 10.6 +/- 1.9, respectively; both P < 0.05, compared with decidua or endometrium). No difference of IL-11Ralpha mRNA level was found between NP and AP (1.7 +/- 0.3 vs. 1.9 +/- 0.4 in deciduas; 7.6 +/- 1.3 vs. 10.6 +/- 1.9 in villi; both P > 0.05). In situ hybridization localized IL-11Ralpha mRNA expression in proliferative phase endometrium (stroma only), secretory phase endometrium (stroma and gland), decidua (stroma and gland), and villi (trophoblast and stroma). The staining intensities were not distinctly different between different groups of samples or between different cell types in a sample. No difference in IL-11Ralpha expression was found between NP and AP when either decidua or chorionic villi was analyzed. IL-11 mRNA level was not detected in the proliferative phase (relative level, 0.0 +/- 0.0), was barely detectable in the secretory phase (0.03 +/- 0.02), and was significantly increased in decidua (1.7 +/- 0.2 and 0.1 +/- 0.1, respectively, for NP and AP) and chorionic villi (13.0 +/- 2.2 and 0.2 +/- 0.1). In addition, IL-11 mRNA level was higher in NP than in AP both in decidua (1.7 +/- 0.2 vs. 0.1 +/- 0.1; P = 0.03) and in villi (13.0 +/- 2.2 vs. 0.2 +/- 0.1; P < 0.001). Immunohistochemistry study showed that IL-11 was nearly absent in endometrium in both phases, but clearly detectable in decidua and villi. Consistent with the results of quantitative PCR, the staining intensity was stronger in villi and decidua from NP than those from AP. The spatial and temporal changes in IL-11 and its receptor observed in this study suggest that IL-11 may be produced both by the embryo (predominantly) and the decidual cells and exerts its action on chorionic villi and decidua in an autocrine or paracrine manner. In the presence of a baseline level of IL-11Ralpha, IL-11 may subsequently regulate placentation and decidualization for the maintenance of a NP. The finding of decreased IL-11 expression in the absence of any change in IL-11Ralpha in AP suggests that defective expression of IL-11 but not IL-11Ralpha may account for certain cases of AP.

Genes involved in implantation

The endometrium is normally a hostile environment for an embryo, except for a short phase in each reproductive cycle known as the 'window of receptivity'. The precise molecular events involved in this transformation are not well understood. Application of state-of-the-art techniques of the 1990s has identified some of the genes involved, which are reviewed here. Mice with a null mutation in either the gene for leukemia inhibitory factor or the interleukin-11 receptor alpha chain are infertile, owing in both cases to a failure of embryo implantation. Both of these genes are expressed in the human endometrium with patterns suggesting a role in human fertility. The technique of RNA differential display has been applied to a comparison of the expression of genes at implantation sites v. inter-implantation sites in the mouse uterus on the first day of implantation, and has defined additional genes whose products may be important for this process. Among these are the calcium-binding protein D9K, the monoclonal non-specific suppressor factor beta, and the splicing factor SC35. The major challenge is to determine whether manipulation of such genes can increase or decrease endometrial receptivity in humans.

IL-11: insights in asthma from overexpression transgenic modeling

The evolution of our understanding of IL-11 mirrors, in many ways, the problems that are faced by investigators in the post-genome era and the types of techniques that might need to be used to deal with these issues. IL-11 was discovered as a soluble factor in fibroblast supernatants that stimulated the proliferation of "IL-6-dependent" plasmacytoma cells. It was subsequently demonstrated to be an important stimulator of platelet reconstitution and a pleiotropic regulator of nonrespiratory tissues. In the lung, IL-11 is produced by a variety of structural cells and eosinophils in response to a variety of stimuli, including TGF-beta, major basic proteins, and viruses. IL-11 is also detected in exaggerated quantities at sites of virus infection. Its potential effector functions at these sites were defined with constitutive and inducible overexpression transgenic modeling systems which demonstrated that IL-11 causes nodular mononuclear infiltrates, airway remodeling with subepithelial fibrosis, airways obstruction, and airways hyperresponsiveness and can block alveolar development when expressed during development. In accord with these murine findings, IL-11 is selectively expressed in eosinophils and epithelial cells in patients with moderate and severe asthma where expression correlates directly with disease severity and inversely with FEV(1). Studies using transgenic mice also demonstrated that IL-11 inhibits antigen-induced tissue inflammation. Thus IL-11 might be an important regulator of inflammatory and remodeling responses in the asthmatic airway.

Cloning of rat interleukin 11 and interleukin 11 receptor alpha chain and analysis of their expression in rat uterus in the peri-implantation period

Studies in mice have shown that interleukin 11 (IL-11) signalling is required for female fertility. In the absence of IL-11, decidualization is markedly retarded and implantation fails. IL-11 acts via a heterodimeric receptor composed of a ligand-specific receptor alpha chain (IL-11R alpha) and the signalling moiety gp130. This study reports the cloning of genes encoding rat IL-11 and IL-11R alpha. RNase protection was used to demonstrate that expression of IL-11 is upregulated in the rat uterus at the initiation of implantation at 5.5 days after mating. Expression of the genes encoding the two receptor components, IL11Ra and gp130, did not change throughout the peri-implantation period. In situ hybridization studies revealed that, as in mice, expression of IL-11 was high in the primary decidual zone at the time of the attachment reaction, whereas IL11Ra was expressed throughout primary and secondary decidua. Conservation of the temporal and spatial expression of IL-11 and IL-11R alpha in the uterus of the mouse and rat during the peri-implantation period will facilitate future studies investigating the role of IL-11 in fertility.

Nrl and Sp nuclear proteins mediate transcription of rod-specific cGMP-phosphodiesterase beta-subunit gene: involvement of multiple response elements

cGMP-phosphodiesterase (PDE) is the key effector in rod photoreceptor signal transduction. Mutations in the gene encoding its catalytic beta-subunit (beta-PDE) cause retinal degenerations leading to blindness. We report that the short -93 to +53 sequence in the upstream region of this gene is sufficient for beta-PDE transcription in both Y79 human retinoblastoma cells and Xenopus embryo heads maintained ex vivo. This sequence also functions as a minimal rod-specific promoter in transgenic Xenopus tadpoles. The Nrl transcription factor binds in vitro to the betaAp1/NRE regulatory element located within this region and transactivates it when overexpressed in nonretinal 293 embryonic kidney cells. We also found a G/C-rich activator element, beta/GC, important for promoter activity in Y79 retinoblastoma cells and Xenopus embryos. Both the ubiquitous Sp1 and the central nervous system-specific Sp4 transcription factors are expressed in retina and interact with this element in vitro. Electrophoretic mobilities of beta/GC-Y79 nuclear protein complexes are altered by antibodies against Sp1 and Sp4. Thus, our results implicate Nrl, Sp1, and Sp4 in transcriptional regulation of the rod-specific minimal beta-PDE promoter. We also conclude that Xenopus laevis is an efficient system for analyzing the human beta-PDE promoter and may be used to study other human retinal genes ex vivo and in vivo.

Over-expression of the functional interleukin-11 alpha receptor in the development of B-cell chronic lymphocytic leukemia

Several cytokines have been found to play a role in the pathogenesis of B-CLL. In the present study using reverse-transcriptase polymerase chain reaction (RT-PCR), FACS analysis and immunofluorescence we have shown the constitutive expression of IL-11 and IL-11R alpha in B-chronic lymphocytic leukemia (B-CLL). The expression level of IL-11R alpha in B-CLL cells is much higher than in PBL of normal donors. Recombinant human IL-11 (rhIL-11) activates B-CLL cells, leading to morphologic alterations of the cells and increase in cell number and size. Short-term cultivation in the presence of rhIL-11 did not lead to quantitative changes in the ratio of the living vs apoptotic and dead cells. However, in contrast to rhIL-6, pretreatment with rhIL-11, did not cause B-CLL cells to be resistant to the action of dexamethasone. These data suggest an essential role for the IL-11/IL11 R alpha system in the pathogenesis of the malignant B-CLL cells.

Interleukin-6 family cytokines: signaling and effects in human airway smooth muscle cells

Interleukin (IL)-1β induces cyclooxygenase (COX)-2 expression and prostanoid formation in cultured human airway smooth muscle (HASM) cells. In other cell types, IL-6 family cytokines induce COX-2 or augment IL-1β-induced COX-2 expression. The purpose of this study was to determine whether IL-6 family cytokines were involved in COX-2 expression in HASM cells. RT-PCR was used to demonstrate that the necessary receptor components for IL-6-type cytokine binding are expressed in HASM cells. IL-6 and oncostatin M (OSM) each caused a dose-dependent phosphorylation of signal transducer and activator of transcription-3, whereas IL-11 did not. IL-6, IL-11, and OSM alone had no effect on COX-2 expression. However, OSM caused dose-dependent augmentation of COX-2 expression and prostaglandin (PG) E2release induced by IL-1β. In contrast, IL-6 and IL-11 did not alter IL-1β-induced COX-2 expression. IL-6 did increase IL-1β-induced PGE2formation in unstimulated cells but not in cells stimulated with arachidonic acid (AA; 10−5M), suggesting that IL-6 effects were mediated at the level of AA release. Our results indicate that IL-6 and OSM are capable of inducing signaling in HASM cells. In addition, OSM and IL-1β synergistically cause COX-2 expression and PGE2release.

The role of IL-II in hematopoiesis as revealed by a targeted mutation of its receptor

Interleukin 11 (IL-11) is a pleiotropic growth factor with several actions in common with members of the IL-6 family. IL-11 utilizes a specific receptor chain encoded by two genes, IL-11Ra, which is expressed in hematopoietic and other tissues and, IL-11Ra2, which has a restricted pattern of expression. The actions of IL-11 in the hematopoietic compartment include support of multilineage and committed progenitors contributing to myeloid, erythroid, megakaryocyte, and lymphoid lineages. IL-11 demonstrates a prominent thrombopoietic activity which is being evaluated in clinical trials. In contrast to the multiple in vitro and in vivo effects of IL-11, mice with a targeted mutation of the IL-11Ra gene (IL-11Ra-/-) did not exhibit an overt hematological phenotype. Generation of a null phenotype was confirmed by independent assays. The numbers of progenitor cells of various lineages as well as their terminally differentiated progeny were undisturbed in the IL-11Ra-/- mice. In addition, the mutant mice were able to respond appropriately to increased demand in situations of hematopoietic stress. This study has highlighted the growth factor redundancy operative in the hematopoietic compartment, and in addition, has served to identify a critical action of IL-11 in nonhematopoietic organs.

Identification of the domain in the human interleukin-11 receptor that mediates ligand binding

The interleukin-11 receptor (IL-11R) belongs to the hematopoietic receptor superfamily. The functional receptor complex comprises IL-11, IL-11R and the signal-transducing subunit gp130. The extracellular part of the IL-11R consists of three domains: an N-terminal immunoglobulin-like domain, D1, and two fibronectin-type III-like (FNIII) domains and D2 and D3. The two FNIII domains comprise the cytokine receptor-homology region defined by a set of four conserved cysteine residues in the N-terminal domain (D2) and a WSXWS sequence motif in the C-terminal domain (D3). We investigated the structural and functional role of the third extracellular receptor domain of IL-11R. A molecular model of the human IL-11/IL-11R complex allowed the identification of amino acid residues in IL-11R to be involved in ligand binding. Most of them were located in the third extracellular domain, which therefore should be able to bind with high affinity to IL-11. To prove this prediction, domain D3 of the IL-11R was expressed in Escherichia coli, refolded and purified. For structural characterization, circular dichroism, fluorescence and NMR spectroscopy were used. By plasmon resonance experiments, we show that the ligand-binding capacity of this domain is as high as that one for the whole receptor. These results provide a basis for further structural investigations that could be used for the rational design of potential agonists and antagonists essential in human therapy.

Interleukin-11 receptor expression in primary ovarian carcinomas

OBJECTIVES

The objectives of this study were to determine (1) the frequency of expression of the interleukin-11 receptor alpha subunit (IL-11Ralpha) and its signal transducing subunit, gp130, among primary ovarian carcinomas; (2) the frequency of expression of IL-11 in ovarian carcinomas; and (3) the potential role IL-11 might have in ovarian cancer cell biology.

METHODS

An immunohistochemical assay was used to determine the expression of IL-11Ralpha and the gp130 cofactor among primary ovarian carcinomas; the expression of IL-11 in ovarian malignancies was determined using reverse transcription polymerase chain reaction (RT-PCR). The ability of IL-11 to stimulate [3H]thymidine incorporation in IL-11R-expressing ovarian carcinoma cell lines (OVCAR-3 and SKOV-3) and/or abrogate cell death mediated by apoptosis-inducing agents using an ELISA assay that quantitates DNA fragmentation was also studied.

RESULTS

IL-11Ralpha was expressed in the malignant epithelial cells of 45 of 48 (93.8%) primary ovarian carcinoma samples studied. In 45 primary ovarian carcinoma samples where both components of the IL-11 receptor (IL-11Ralpha and gp130) were examined, coexpression was observed in 42 (93.3%). Expression of the IL-11 receptor components was also found in the stromal layer. Coexpression of IL-11Ralpha and gp130 was commonly observed in both benign ovarian tumors and in the epithelial layer of normal ovaries. In contrast, IL-11 mRNA was expressed in only 3 of 21 malignant samples studied (14.3%). Recombinant human IL-11 was unable either to stimulate [3H]thymidine incorporation or to block cell death effected by paclitaxel or Fas-activating antibodies in in vitro assays using OVCAR -3 or SKOV-3 cells.

CONCLUSIONS

The IL-11 receptor system is commonly expressed in both malignant and nonmalignant ovarian tissues, although its function in ovarian epithelial cell biology remains unclear.

Increased expression of the interleukin-11 receptor and evidence of STAT3 activation in prostate carcinoma

Previous investigations have shown that interleukin-6, a member of the JAK-STAT activating family of cytokines, plays an important role in prostate carcinoma. Here we demonstrate the co-expression of another member of this cytokine family, interleukin-11 (IL-11), and components of its receptor (interleukin-11 receptor; IL-11R), ie, IL-11Ralpha (involved in ligand recognition), and gp130 (involved in signal transduction) in cultured normal and malignant prostate-derived epithelial cell lines. In the DU-145 prostate carcinoma cell line, rhIL-11 stimulates a transient and dose-dependent increase in the tyrosine 705-phosphorylated, active form of STAT3 (STAT3 P-Tyr705), involved in the downstream signaling of IL-11R and other members of the gp130-dependent receptors. The ability of IL-11 to activate STAT3 in prostate-derived cells may be mechanistically important, given recent data suggesting that constitutively activated STAT3 may be associated with the malignant phenotype. In 51 human primary tissues derived from normal prostate, benign prostatic hyperplasia, and prostate carcinomas, IL-11Ralpha and gp130 were commonly expressed, with a statistically significant elevation in the expression of IL-11Ralpha in prostate carcinoma. Also, the tyrosine-phosphorylated, activated form of STAT3 was observed more prominently in the nuclei of cells residing in malignant glands compared to those in nonmalignant samples. Thus, the IL-11 receptor system is up-regulated in prostate carcinoma, and may be one part of a cytokine network that maintains STAT3 in its activated form in these tissues.

Interleukin-11 modulates Th1/Th2 cytokine production from activated CD4+ T cells

Recombinant human interleukin-11 (rHuIL-11) is a pleiotropic cytokine with effects on multiple cell types. rHuIL-11 reduces activated macrophage activity and downregulates production of proinflammatory mediators, such as tumor necrosis factor-alpha (TNF-alpha) and nitric oxide (NO). In vitro and in vivo, rHuIL-11 inhibits production of key immunostimulatory cytokines, including IL-12 and interferon-gamma (IFN-gamma). rHuIL-11 has recently demonstrated immunomodulatory activity to downregulate IFN-gamma production, increase IL-4 production, and reduce inflammatory tissue injury in a human psoriasis clinical trial. The cellular mechanisms of these effects are not fully elucidated. We demonstrate here that expression of gp130 and IL-11 receptor (IL-11R) alpha mRNA, components of the IL-11R complex, are detected in human and murine CD4(+) and CD8(+) lymphocytes, suggesting that rHuIL-11 can directly interact with T cells. In a cell culture model of murine T cell differentiation, rHuIL-11 acts to inhibit IL-2 production as well as IL-12-induced IFN-gamma production and enhances IL-4 and IL-10 production. rHuIL-11 had no effect on T cell proliferation. The ability of rHuIL-11 to modulate cytokine production from activated CD4(+) T cells provides a mechanism through which rHuIL-11 may ameliorate such inflammatory diseases as psoriasis.

Interleukin-11 signals through the formation of a hexameric receptor complex

Interleukin-11 (IL-11) is a member of the gp130 family of cytokines. These cytokines drive the assembly of multisubunit receptor complexes, all of which contain at least one molecule of the transmembrane signaling receptor gp130. IL-11 has been shown to induce gp130-dependent signaling through the formation of a high affinity complex with the IL-11 receptor (IL-11R) and gp130. Site-directed mutagenesis studies have identified three distinct receptor binding sites of IL-11, which enable it to form this high affinity receptor complex. Here we present data from immunoprecipitation experiments, using differentially tagged forms of ligand and soluble receptor components, which show that multiple copies of IL-11, IL-11R, and gp130 are present in the receptor complex. Furthermore, it is demonstrated that sites II and III of IL-11 are independent gp130 binding epitopes and that both are essential for gp130 dimerization. We also show that a stable high affinity complex of IL-11, IL-11R, and gp130 can be resolved by nondenaturing polyacrylamide gel electrophoresis, and its composition verified by second dimension denaturing polyacrylamide gel electrophoresis. Results indicate that the three receptor binding sites of IL-11 and the Ig-like domain of gp130 are all essential for this stable receptor complex to be formed. We therefore propose that IL-11 forms a hexameric receptor complex composed of two molecules each of IL-11, IL-11R, and gp130.

Developmental differences in alternative splicing of the NR1 protein in rat cortex and cerebellum

Expression of the C-terminal cassettes of the NR1 protein was examined using a quantitative Western blot method with cassette-specific antibodies. Measurements were made of the percent of total NR1 protein that contained a specific cassette in both the cerebellum and cortex over development. In the cortex, the C1 cassette was shown to be present in about half of total NR1 protein with no change over development. While about half of total NR1 in the cerebellum at postnatal day 42 (P42) contained the C1 cassette, little NR1 protein with this cassette was seen at young ages. In both the cerebellum and cortex, the C2 and C2' cassettes showed opposite developmental patterns, with the C2 cassette decreasing and the C2' cassette increasing over age. Together with previous data on the expression of the N1 cassette, this study describes the alternatively spliced forms of NR1 protein that are dominant at different ages. In the young cerebellum, the NR1(001) form appeared dominant, while in the young cortex there appeared to be a mix of NR1(001) and NR1(011). The most common splice forms of NR1 protein in the adult cerebellum appeared to be NR1(111) and NR1(100). In the adult cortex, there appeared to be a mix of NR1(001) and NR1(011). These data on the expression of the alternatively spliced forms of NR1 allow predictions on the possible characteristics of NMDA receptors in different regions at specific ages.

Temporal expression of mRNAs for neuropoietic cytokines, interleukin-11 (IL-11), oncostatin M (OSM), cardiotrophin-1 (CT-1) and their receptors (IL-11Ralpha and OSMRbeta) in peripheral nerve injury

The mRNA expression pattern of the neuropoietic cytokines, interleukin-11 (IL-11), oncostatin M (OSM) and cardiotrophin-1 (CT-1), and their receptor components (IL-11Ralpha and OSMRbeta) was examined in peripheral nerves on two different types of injury, crush and transection. The IL-11 mRNA increased after nerve damage and immediately returned to control levels. The OSM mRNA expression increased rapidly after nerve injury and relatively high expressions were maintained for at least 14 days. The CT-1 mRNA was not expressed in any time before and after the injury. Interestingly, IL-11Ralpha was expressed in the intact nerve and decreased after injury. The expression of OSMRbeta increased slightly after the injury. Moreover, temporal mRNA expression pattern of these neuropoietic cytokines and receptors was similar between the crushed and transected models. Each neuropoietic cytokine of IL-11, OSM and CT-1 has its own specific temporal mRNA expression pattern, which is also different from those of ciliary neuro-trophic factor (CNTF), leukemia inhibitory factor (LIF) and interleukin-6 (IL-6). These results suggest that all neuropoietic cytokines have distinctive functions in nerve degeneration and repair process in response to peripheral nerve injury.

Monoclonal antibodies against the human interleukin-11 receptor alpha-chain (IL-11Ralpha) and their use in studies of human mononuclear cells

A panel of 14 hybridoma cell lines secreting monoclonal antibodies against the human interleukin-11 receptor alpha chain (hIL-11Ralpha) was obtained using two different approaches. Two antibodies were raised against peptides of the N- and C-terminal sequences, respectively, of the extracellular part of the hIL-11Ralpha. Another group of 12 antibodies was generated against a hybrid protein consisting of the extracellular part of the hIL-11Ralpha fused to mature full-length human IL-2. All these antibodies recognized native hIL-11Ralpha and most also recognized the denatured receptor on immunoblots after SDS-PAGE. Four different epitopes were identified on the extracellular part of the hIL-11Ralpha. One epitope, defined by the E27 antibody, is located at the N-terminus and the other three epitopes are clustered in the membrane-proximal, C-terminal region. The antibodies defining epitopes I and II recognized membrane-bound hIL-11Ralpha expressed in gp130/hIL-11Ralpha-co-transfected Ba/F3 cells. The E27 antibody cross-reacted with murine IL-11Ralpha, in agreement with the fact that the N-terminal region is highly conserved between species. The other 13 antibodies all recognized a region between amino acids 319 and 363, which is the membrane-proximal part of the hIL-11Ralpha. This region, which is less conserved between mouse and human, is shown here to be an immunodominant region. Anti-IL-11Ralpha monoclonal antibodies, which have not been described previously enabled us to explore the expression and tissue distribution of IL-11Ralpha on human peripheral blood mononuclear cells and cell lines. The antibodies provide powerful tools for the study of the regulation and function of the receptor.

Regulation of gut and heart left-right asymmetry by context-dependent interactions between xenopus lefty and BMP4 signaling

The Lefty subfamily of TGFbeta signaling molecules has been implicated in early development in mouse, zebrafish, and chick. Here, we show that Xenopus lefty (Xlefty) is expressed both bilaterally in symmetric midline domains and unilaterally in left lateral plate mesoderm and anterior dorsal endoderm. To examine the roles of Xlefty in left-right development, we created a system for scoring gut asymmetry and examined the effects of unilateral Xlefty misexpression on gut development, heart development, and Xnr-1 and XPitx2 expression. In contrast to the unilateral effects of Vg1, Activin, Nodal, or BMPs, targeted expression of Xlefty in either the left or the right side of Xenopus embryos randomized the direction of heart looping, gut coiling, and left-right positioning of the gut and downregulated the asymmetric expression of Xnr-1 and XPitx2. It is currently thought that Lefty proteins act as feedback inhibitors of Nodal signaling. However, this would not explain the effects of right-sided Xlefty misexpression. Here, we show that Xlefty interacts with the signaling pathways of other members of the TGFbeta family during left-right development. Results from coexpression of Xlefty and Vg1 indicate that Xlefty can nullify the effects of Vg1 ectopic expression and that Xlefty is downstream of left-sided Vg1 signaling. Results from coexpression of Xlefty and XBMP4 indicate that XLefty and XBMP4 interact both synergistically and antagonistically in a context-dependent manner. We propose a model in which interactions of Xlefty with multiple members of the TGFbeta family enhance the differences between the right-sided BMP/ALK2/Smad pathway and the left-sided Vg1/anti-BMP/Nodal pathway, leading to left-right morphogenesis of the gut and heart.

Phenotypic effects in Xenopus and zebrafish suggest that one-eyed pinhead functions as antagonist of BMP signalling

Zebrafish one-eyed pinhead (oep) is essential for embryonic axis and dorsal midline formation by promoting Nodal signalling and is thought to act as a permissive factor. Here we describe that oep elicits profound phenotypic effects when overexpressed in Xenopus and zebrafish. In Xenopus, wild-type oep inhibits mesoderm induction, disrupts axis formation and neuralizes animal caps. A secreted Oep dorsoanteriorizes and neuralizes Xenopus embryos indicative of BMP inhibition. In zebrafish, misexpression of smad1 in oep mutant embryos also reveals an interaction of oep with BMP signalling. Furthermore, the phenotypic effect of nodal overexpression can be rescued by coexpression of oep both in Xenopus and zebrafish. Taken together, our results support an interaction between oep and nodal but they suggest also (1) that the role of oep in Nodal signalling may include negative as well as positive regulation, (2) that oep is able to function in an active fashion and (3) that oep exerts a regulatory effect on the BMP signalling pathway.

The gp130 cytokines interleukin-11 and ciliary neurotropic factor regulate through specific receptors the function and growth of lactosomatotropic and folliculostellate pituitary cell lines

Two of the most potent cytokines regulating anterior pituitary cell function are leukemia inhibitory factor and interleukin-6 (IL-6), which belong to the cytokine receptor family using the common gp130 signal transducer. We studied the actions of two other members of this family, IL-11 and ciliary neurotropic factor (CNTF), on folliculostellate (FS) cells (TtT/GF cell line) and lactosomatotropic cells (GH3 cell line). The messenger RNA (mRNA) for the alpha-chain specific for the IL-11 receptor (1.7 kb) and CNTF receptor (2 kb) are expressed on both cell types. In addition, we detected CNTF receptor mRNA in normal rat anterior pituitary cells. IL-11 (1.25-5 nM) dose dependently stimulated the proliferation of FS cells. CNTF, at doses from 0.4-2 nM, also significantly stimulated the growth of these cells. In addition, both cytokines significantly stimulated proliferation of lactosomatotropic GH3 cells, and CNTF stimulated hormone production (GH and PRL) at 24 h by these cells. At 16-72 h, IL-11 stimulates the secretion of the angiogenic factor vascular endothelial growth factor by FS cells. In addition, both GH3 and FS cells express CNTF mRNA. These data suggest that IL-11 and CNTF may act as growth and regulatory factors in anterior pituitary cells.

IL-11 activates human endothelial cells to resist immune-mediated injury

IL-11, a gp130-signaling cytokine, is protective in several in vivo models of immune-mediated and inflammatory injury. HUVECs express IL-11 receptor alpha-chain and gp130. Human IL-11 causes rapid (2-10 min) tyrosine phosphorylation of gp130. IL-11 at 0.1 and 10 ng/ml induces tyrosine phosphorylation of STAT3 and STAT1, respectively, although maximal responses require 50 ng/ml. Phospho-STAT3 and phospho-STAT1 levels peak rapidly (2.5 min) and disappear by 60 min. The p42 and p44 mitogen-activated protein kinases (MAPKs) are phosphorylated in response to 0.3 ng/ml IL-11 with maximal activation at 30 ng/ml IL-11. Phosphorylation of p42 and p44 MAPKs, which can be prevented by a mitogen-activated protein/extracellular signal-related kinase kinase-1 inhibitor, peaks by 15-20 min and largely disappears by 40 min. IL-11 does not activate NF-kappaB nor does it inhibit NF-kappaB activation by TNF. Similarly, IL-11 neither induces E-selectin or ICAM-1 nor blocks induction by TNF. Although IL-11 does not alter class I MHC complex molecule expression, pretreatment with 0.5 ng/ml IL-11 partially protects HUVECs against lysis by allospecific class I MHC-restricted cytolytic T lymphocytes or by anti-class I MHC Ab plus heterologous C. IL-11-induced cytoprotection is protein synthesis dependent and may depend on mitogen-activated protein/extracellular signal-related kinase kinase-1. Our results indicate that low (i.e., STAT3- and MAPK-activating) concentrations of IL-11 confer resistance to immune-mediated injury in cultured HUVECs without inhibiting proinflammatory responses.

Interleukin-11 enhancement of VLA-5 mediated adhesion of CD34+ cells from cord blood to fibronectin is associated with the PI-3 kinase pathway

Adhesion is required for cell growth, differentiation, survival, and function. Cell adhesion is mediated by a structurally diverse group of plasma membrane receptors, each exhibiting specialized ligand-binding properties that are needed for specific tasks. Integrin-mediated adhesion is important for hematopoietic stem (HSC)/progenitor (HPC) cell survival and may prevent programmed cell death. Interleukin (IL)-11, a multi-functional cytokine secreted by the bone marrow environment, plays an important role in regulating growth and differentiation of HSCs/HPCs. In this report, we demonstrate that IL-11 enhanced adhesion of freshly isolated and 3 day-expanded CD34+ cells to immobilized fibronectin. the expression of very late antigen (VLA)-4 and VLA-5 integrins was detected on CD34+ cells. CD34+ cells also expressed a-chain and gp130 subunits of the IL-11 receptor (R). Enhanced adhesion by IL-11 was mediated via activation of VLA-5 integrins, since this action could be blocked by monoclonal antibodies against beta 1 and alpha 5, but not alpha 4, integrins. Addition of phosphatidylinositol (PI)-3 kinase inhibitors blocked IL-11 enhanced adhesion of CD34+ cells to fibronectin. The results suggest that this enhanced adhesion is associated with the PI-3 kinase pathway, an inside-out signaling pathway.