1
|
Ben-Shlomo A, Deng N, Ding E, Yamamoto M, Mamelak A, Chesnokova V, Labadzhyan A, Melmed S. DNA damage and growth hormone hypersecretion in pituitary somatotroph adenomas. J Clin Invest 2021; 130:5738-5755. [PMID: 32673291 DOI: 10.1172/jci138540] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 07/14/2020] [Indexed: 12/22/2022] Open
Abstract
Drivers of sporadic benign pituitary adenoma growth are largely unknown. Whole-exome sequencing of 159 prospectively resected pituitary adenomas showed that somatic copy number alteration (SCNA) rather than mutation is a hallmark of hormone-secreting adenomas and that SCNAs correlate with adenoma phenotype. Using single-gene SCNA pathway analysis, we observed that both cAMP and Fanconi anemia DNA damage repair pathways were affected by SCNAs in growth hormone-secreting (GH-secreting) somatotroph adenomas. As somatotroph differentiation and GH secretion are dependent on cAMP activation and we previously showed DNA damage, aneuploidy, and senescence in somatotroph adenomas, we studied links between cAMP signaling and DNA damage. Stimulation of cAMP in C57BL/6 mouse primary pituitary cultures using forskolin or a long-acting GH-releasing hormone (GHRH) analog increased GH production and DNA damage measured by H2AX phosphorylation and a comet assay. Octreotide, a somatostatin receptor ligand that targets somatotroph adenoma GH secretion in patients with acromegaly, inhibited cAMP and GH and reversed DNA damage induction. In vivo long-acting GHRH treatment also induced pituitary DNA damage in mice. We conclude that cAMP, which induces somatotroph proliferation and GH secretion, may concomitantly induce DNA damage, potentially linking hormone hypersecretion to SCNA and genome instability. These results elucidating somatotroph adenoma pathophysiology identify pathways for targeted treatment.
Collapse
Affiliation(s)
| | - Nan Deng
- Biostatistics and Bioinformatics Research Center, Samuel Oschin Comprehensive Cancer Institute, and
| | | | | | - Adam Mamelak
- Pituitary Center, Department of Medicine.,Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | | | | | | |
Collapse
|
2
|
Marques P, Grossman AB, Korbonits M. The tumour microenvironment of pituitary neuroendocrine tumours. Front Neuroendocrinol 2020; 58:100852. [PMID: 32553750 DOI: 10.1016/j.yfrne.2020.100852] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 05/26/2020] [Accepted: 06/02/2020] [Indexed: 02/06/2023]
Abstract
The tumour microenvironment (TME) includes a variety of non-neoplastic cells and non-cellular elements such as cytokines, growth factors and enzymes surrounding tumour cells. The TME emerged as a key modulator of tumour initiation, progression and invasion, with extensive data available in many cancers, but little is known in pituitary tumours. However, the understanding of the TME of pituitary tumours has advanced thanks to active research in this field over the last decade. Different immune and stromal cell subpopulations, and several cytokines, growth factors and matrix remodelling enzymes, have been characterised in pituitary tumours. Studying the TME in pituitary tumours may lead to a better understanding of tumourigenic mechanisms, identification of biomarkers useful to predict aggressive disease, and development of novel therapies. This review summarises the current knowledge on the different TME cellular/non-cellular elements in pituitary tumours and provides an overview of their role in tumourigenesis, biological behaviour and clinical outcomes.
Collapse
Affiliation(s)
- Pedro Marques
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
| | - Ashley B Grossman
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
| | - Márta Korbonits
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
| |
Collapse
|
3
|
Liu YN, Niu S, Chen WY, Zhang Q, Tao Y, Chen WH, Jiang KC, Chen X, Shi H, Liu A, Li J, Li Y, Lee YC, Zhang X, Huang J. Leukemia Inhibitory Factor Promotes Castration-resistant Prostate Cancer and Neuroendocrine Differentiation by Activated ZBTB46. Clin Cancer Res 2019; 25:4128-4140. [PMID: 30962287 PMCID: PMC7168873 DOI: 10.1158/1078-0432.ccr-18-3239] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 02/22/2019] [Accepted: 03/29/2019] [Indexed: 11/16/2022]
Abstract
PURPOSE The molecular targets for castration-resistant prostate cancer (CRPC) are unknown because the disease inevitably recurs, and therapeutic approaches for patients with CRPC remain less well understood. We sought to investigate regulatory mechanisms that result in increased therapeutic resistance, which is associated with neuroendocrine differentiation of prostate cancer and linked to dysregulation of the androgen-responsive pathway. EXPERIMENTAL DESIGN The underlying intracellular mechanism that sustains the oncogenic network involved in neuroendocrine differentiation and therapeutic resistance of prostate cancer was evaluated to investigate and identify effectors. Multiple sets of samples with prostate adenocarcinomas and CRPC were assessed via IHC and other assays. RESULTS We demonstrated that leukemia inhibitory factor (LIF) was induced by androgen deprivation therapy (ADT) and was upregulated by ZBTB46 in prostate cancer to promote CRPC and neuroendocrine differentiation. LIF was found to be induced in patients with prostate cancer after ADT and was associated with enriched nuclear ZBTB46 staining in high-grade prostate tumors. In prostate cancer cells, high ZBTB46 output was responsible for the activation of LIF-STAT3 signaling and neuroendocrine-like features. The abundance of LIF was mediated by ADT-induced ZBTB46 through a physical interaction with the regulatory sequence of LIF. Analysis of serum from patients showed that cases of higher tumor grade and metastatic prostate cancer exhibited higher LIF titers. CONCLUSIONS Our findings suggest that LIF is a potent serum biomarker for diagnosing advanced prostate cancer and that targeting the ZBTB46-LIF axis may therefore inhibit CRPC development and neuroendocrine differentiation after ADT.
Collapse
Affiliation(s)
- Yen-Nien Liu
- Graduate Institute of Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan. .,TMU Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei, Taiwan.,Ph.D. Program for Cancer Molecular Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Shaoxi Niu
- Department of Urology, State Key Laboratory of Kidney Diseases, Chinese PLA General Hospital, Chinese PLA Medical Academy, Beijing, China
| | - Wei-Yu Chen
- Department of Pathology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan.,Department of Pathology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Qingfu Zhang
- Department of Pathology, The First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Yulei Tao
- Department of Pathology, Duke University Medical Center, Durham, North Carolina
| | - Wei-Hao Chen
- Graduate Institute of Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Kuo-Ching Jiang
- Graduate Institute of Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Xufeng Chen
- Department of Pathology, Duke University Medical Center, Durham, North Carolina
| | - Huaiyin Shi
- Department of Pathology, The PLA General Hospital, Beijing, China
| | - Aijun Liu
- Department of Pathology, The PLA General Hospital, Beijing, China
| | - Jinhang Li
- Department of Pathology, The PLA General Hospital, Beijing, China
| | - Yanjing Li
- Department of Pathology, Duke University Medical Center, Durham, North Carolina
| | - Yi-Chao Lee
- PhD Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.,Center for Neurotrauma and Neuroregeneration, Taipei Medical University, Taipei, Taiwan
| | - Xu Zhang
- Department of Urology, State Key Laboratory of Kidney Diseases, Chinese PLA General Hospital, Chinese PLA Medical Academy, Beijing, China.
| | - Jiaoti Huang
- Department of Pathology, Duke University Medical Center, Durham, North Carolina.
| |
Collapse
|
4
|
Zheng X, Li S, Zhang W, Zang Z, Hu J, Yang H. Current biomarkers of invasive sporadic pituitary adenomas. ANNALES D'ENDOCRINOLOGIE 2016; 77:658-667. [PMID: 27659267 DOI: 10.1016/j.ando.2016.02.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 01/29/2016] [Accepted: 02/21/2016] [Indexed: 12/22/2022]
Abstract
Though pituitary adenomas (PA) are considered benign, some of them exhibit invasive behaviors such as recurrence and low rate of total surgical resection. Reliable prognostic biomarkers for invasive PA are highly desired; however they remain to be identified. In this review, we summarize the current controversial findings of biomarkers for invasive sporadic PA, and we discuss the possible reasons for the controversies.
Collapse
Affiliation(s)
- Xin Zheng
- Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, 183, Xinqiao Main Street, Shapingba District, Chongqing, China
| | - Song Li
- Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, 183, Xinqiao Main Street, Shapingba District, Chongqing, China
| | - Weihua Zhang
- Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
| | - Zhenle Zang
- Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, 183, Xinqiao Main Street, Shapingba District, Chongqing, China
| | - Jintao Hu
- Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, 183, Xinqiao Main Street, Shapingba District, Chongqing, China
| | - Hui Yang
- Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, 183, Xinqiao Main Street, Shapingba District, Chongqing, China.
| |
Collapse
|
5
|
Zhou C, Jiao Y, Wang R, Ren SG, Wawrowsky K, Melmed S. STAT3 upregulation in pituitary somatotroph adenomas induces growth hormone hypersecretion. J Clin Invest 2015; 125:1692-702. [PMID: 25774503 DOI: 10.1172/jci78173] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 01/29/2015] [Indexed: 01/09/2023] Open
Abstract
Pituitary somatotroph adenomas result in dysregulated growth hormone (GH) hypersecretion and acromegaly; however, regulatory mechanisms that promote GH hypersecretion remain elusive. Here, we provide evidence that STAT3 directly induces somatotroph tumor cell GH. Evaluation of pituitary tumors revealed that STAT3 expression was enhanced in human GH-secreting adenomas compared with that in nonsecreting pituitary tumors. Moreover, STAT3 and GH expression were concordant in a somatotroph adenoma tissue array. Promoter and expression analysis in a GH-secreting rat cell line (GH3) revealed that STAT3 specifically binds the Gh promoter and induces transcription. Stable expression of STAT3 in GH3 cells induced expression of endogenous GH, and expression of a constitutively active STAT3 further enhanced GH production. Conversely, expression of dominant-negative STAT3 abrogated GH expression. In primary human somatotroph adenoma-derived cell cultures, STAT3 suppression with the specific inhibitor S3I-201 attenuated GH transcription and reduced GH secretion in the majority of derivative cultures. In addition, S3I-201 attenuated somatotroph tumor growth and GH secretion in a rat xenograft model. GH induced STAT3 phosphorylation and nuclear translocation, indicating a positive feedback loop between STAT3 and GH in somatotroph tumor cells. Together, these results indicate that adenoma GH hypersecretion is the result of STAT3-dependent GH induction, which in turn promotes STAT3 expression, and suggest STAT3 as a potential therapeutic target for pituitary somatotroph adenomas.
Collapse
|
6
|
Amitani M, Asakawa A, Amitani H, Inui A. Control of food intake and muscle wasting in cachexia. Int J Biochem Cell Biol 2013; 45:2179-85. [DOI: 10.1016/j.biocel.2013.07.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 07/16/2013] [Accepted: 07/16/2013] [Indexed: 12/14/2022]
|
7
|
Khattak MNK, Buchfelder M, Kleindienst A, Schöfl C, Kremenevskaja N. CRH and SRIF have opposite effects on the Wnt/β-catenin signalling pathway through PKA/GSK-3β in corticotroph pituitary cells. Cancer Invest 2010; 28:797-805. [PMID: 20690801 DOI: 10.3109/07357907.2010.494318] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The Wnt/ß-catenin signalling pathway is involved in tumorigenesis including endocrine tumors. We investigated the Wnt/ß-catenin pathway's modulation by corticotropin-releasing hormone (CRH) and somatostatin or somatotropin release-inhibiting factor (SRIF) in mouse pituitary AtT-20 corticotroph cells. The Wnt/β-catenin signalling pathway was activated by CRH and inhibited by SRIF. We provide evidence that cAMP/PKA signalling is involved affecting the GSK-3β phosphorylation status at phospho-GSK-3β (Ser9), thereby altering β-catenin degradation downstream. Furthermore, CRH and SRIF showed concordant effects on cell proliferation. Our data demonstrate an important role of the Wnt/β-catenin pathway in the proliferative control of pituitary corticotroph cells and describe a mechanism for its regulation by CRH and SRIF.
Collapse
|
8
|
Razavi Nematollahi L, Kitabchi AE, Stentz FB, Wan JY, Larijani BA, Tehrani MM, Gozashti MH, Omidfar K, Taheri E. Proinflammatory cytokines in response to insulin-induced hypoglycemic stress in healthy subjects. Metabolism 2009; 58:443-8. [PMID: 19303962 DOI: 10.1016/j.metabol.2008.10.018] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Accepted: 10/06/2008] [Indexed: 11/16/2022]
Abstract
Hyperglycemic crises of diabetic ketoacidosis and nonketotic hyperglycemia are associated with elevation of counterregulatory hormones and proinflammatory cytokines, markers of lipid peroxidation, and oxidative stress. To investigate if other conditions besides hyperglycemia could evoke such a prompt increase in cytokine levels, lipid peroxidation, and oxidative stress markers, we induced hypoglycemic stress by standard insulin tolerance test and measured proinflammatory cytokines, markers of lipid peroxidation, reactive oxygen species (ROS), and counterregulatory hormones. Insulin tolerance test was performed in 13 healthy male subjects with no history of infection, cardiovascular risk factors, or abnormal glucose. At baseline and at 30, 45, 60, 120, and 240 minutes after insulin injection, the following parameters were measured: glucose, cortisol, corticotropin, epinephrine (EP), norepinephrine (NE), growth hormone, tumor necrosis factor (TNF)-alpha, interleukin (IL) 1beta, IL-6, IL-8, free fatty acids, white blood cells, lipid peroxidation markers by thiobarbituric acid assay, and ROS by dichlorofluorescein method. The peak value of white blood cell count at 120 minutes was significantly associated with the peak values of NE at 30 minutes and cortisol at 60 minutes. By comparing the area under the curve of measured parameters, EP emerged as significant predictor of TNF-alpha (P = .05) and IL-8 (P = .027). Cortisol emerged as predictor of IL-1beta significantly (P = .05). Corticotropin predicted area under the curve of IL-6 with borderline significance (P = .06). In the present study, insulin-induced hypoglycemia in nondiabetic male subjects is associated with increased proinflammatory cytokines (TNF-alpha, IL-1beta, IL-6, and IL-8), markers of lipid peroxidation, ROS, and leukocytosis. Elevations of NE, EP, corticotropin, and cortisol in hypoglycaemia are associated with the elevation of the proinflammatory cytokines and leukocytosis.
Collapse
|
9
|
Denef C. Paracrinicity: the story of 30 years of cellular pituitary crosstalk. J Neuroendocrinol 2008; 20:1-70. [PMID: 18081553 PMCID: PMC2229370 DOI: 10.1111/j.1365-2826.2007.01616.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2007] [Revised: 07/30/2007] [Accepted: 08/13/2007] [Indexed: 11/27/2022]
Abstract
Living organisms represent, in essence, dynamic interactions of high complexity between membrane-separated compartments that cannot exist on their own, but reach behaviour in co-ordination. In multicellular organisms, there must be communication and co-ordination between individual cells and cell groups to achieve appropriate behaviour of the system. Depending on the mode of signal transportation and the target, intercellular communication is neuronal, hormonal, paracrine or juxtacrine. Cell signalling can also be self-targeting or autocrine. Although the notion of paracrine and autocrine signalling was already suggested more than 100 years ago, it is only during the last 30 years that these mechanisms have been characterised. In the anterior pituitary, paracrine communication and autocrine loops that operate during fetal and postnatal development in mammals and lower vertebrates have been shown in all hormonal cell types and in folliculo-stellate cells. More than 100 compounds have been identified that have, or may have, paracrine or autocrine actions. They include the neurotransmitters acetylcholine and gamma-aminobutyric acid, peptides such as vasoactive intestinal peptide, galanin, endothelins, calcitonin, neuromedin B and melanocortins, growth factors of the epidermal growth factor, fibroblast growth factor, nerve growth factor and transforming growth factor-beta families, cytokines, tissue factors such as annexin-1 and follistatin, hormones, nitric oxide, purines, retinoids and fatty acid derivatives. In addition, connective tissue cells, endothelial cells and vascular pericytes may influence paracrinicity by delivering growth factors, cytokines, heparan sulphate proteoglycans and proteases. Basement membranes may influence paracrine signalling through the binding of signalling molecules to heparan sulphate proteoglycans. Paracrine/autocrine actions are highly context-dependent. They are turned on/off when hormonal outputs need to be adapted to changing demands of the organism, such as during reproduction, stress, inflammation, starvation and circadian rhythms. Specificity and selectivity in autocrine/paracrine interactions may rely on microanatomical specialisations, functional compartmentalisation in receptor-ligand distribution and the non-equilibrium dynamics of the receptor-ligand interactions in the loops.
Collapse
Affiliation(s)
- C Denef
- Laboratory of Cell Pharmacology, University of Leuven, Medical School, Leuven, Belgium.
| |
Collapse
|
10
|
Gerez J, Bonfiglio J, Sosa S, Giacomini D, Acuña M, Carbia Nagashima A, Perone MJ, Silberstein S, Renner U, Stalla GK, Arzt E. Molecular transduction mechanisms of cytokine-hormone interactions: role of gp130 cytokines. Exp Physiol 2007. [DOI: 10.1113/expphysiol.2006.036236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
11
|
John CD, Theogaraj E, Christian HC, Morris JF, Smith SF, Buckingham JC. Time-specific effects of perinatal glucocorticoid treatment on anterior pituitary morphology, annexin 1 expression and adrenocorticotrophic hormone secretion in the adult female rat. J Neuroendocrinol 2006; 18:949-59. [PMID: 17076770 DOI: 10.1111/j.1365-2826.2006.01493.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Perinatal glucocorticoid (GC) treatment is increasingly associated with long-term disturbances in hypothalamo-pituitary-adrenocortical function. In the male rat, such treatment induces profound molecular, morphological and functional changes in the anterior pituitary gland at adulthood. To determine whether these effects are sex-specific, we have examined the effects of perinatal dexamethasone treatment on the female pituitary gland, focusing on (i) the integrity of the annexin 1 (ANXA1) dependent regulatory effects of GCs on adrenocorticotrophic hormone (ACTH) release and (ii) corticotroph and folliculo-stellate (FS) cell morphology. Dexamethasone was given to pregnant (gestational days 16-19) or lactating (days 1-7 post partum) rats via the drinking water (1 microg/ml); controls received normal drinking water. Pituitary tissue from the female offspring was examined ex vivo at adulthood (60-90 days). Both treatment regimes reduced the intracellular and cell surface ANXA1 expression, as determined by western blot analysis and quantitative immunogold electron microscopic histochemistry. In addition, they compromised the ability of dexamethasone to suppress the evoked release of ACTH from the excised tissue in vitro, a process which requires the translocation of ANXA1 from the cytoplasm to the cell surface of FS cells. Although neither treatment regime affected the number of FS cells or corticotrophs, both altered the subcellular morphology of these cells. Thus, prenatal dexamethasone treatment increased while neonatal treatment decreased FS cell size and cytoplasmic area. By contrast, corticotroph size was unaffected by either treatment, as also was the size of the secretory granules. Corticotroph granule density and margination were, however, increased markedly by the prenatal treatment, while the neonatal treatment had no effect on granule density but decreased granule margination. Thus, perinatal dexamethasone treatment exerts long-term effects on the female pituitary gland, altering gene expression, cell morphology and the ANXA1-dependent GC regulation of ACTH secretion. The changes are similar but not identical to those reported in the male.
Collapse
Affiliation(s)
- C D John
- Department of Cellular and Molecular Neuroscience, Division of Neuroscience and Mental Health, Imperial College London, Hammersmith Campus, London, UK
| | | | | | | | | | | |
Collapse
|
12
|
McColm JR, Geisen P, Peterson LJ, Hartnett ME. Exogenous leukemia inhibitory factor (LIF) attenuates retinal vascularization reducing cell proliferation not apoptosis. Exp Eye Res 2006; 83:438-46. [PMID: 16643897 PMCID: PMC1828040 DOI: 10.1016/j.exer.2006.01.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2005] [Revised: 01/13/2006] [Accepted: 01/17/2006] [Indexed: 11/28/2022]
Abstract
To study the effect of leukemia inhibitory factor (LIF) on rat retinal vascular development, Sprague-Dawley rats at postnatal age 3 days (p3) were given intraperitoneal (IP) LIF and analysis performed at p6 (p3/6). p7 rats were given intravitreous (IV) LIF and analysis performed at p9 (p7/9). Control animals were PBS injected. At the time of analysis retinal flatmounts were prepared and stained with Griffonia lectin and activated caspase-3. The retinal peripheral avascular area was measured and number of apoptotic cells counted. In vitro, human retinal microvascular endothelial cells (RMVECs) were cultured in media containing LIF, with and without neutralizing antibody to LIF. Cells were stained with activated caspase-3 and apoptotic cells counted. Proliferation was measured by counting cell numbers, and cell cycle stage was determined using propidium iodide staining and FACS analysis. LIF injected either IP or IV had no effect on body weight or total retina area, but significantly increased the peripheral retinal avascular area. In both IP and IV injected groups there was no difference in the number of apoptotic cells between PBS- or LIF-injected groups; although in the p7/9 retinas, both injected groups had significantly more apoptotic cells than the non-injected group. In vitro, there was no effect of LIF on RMVEC apoptosis; however, cell counts were significantly lower in the LIF-treated group. Antibody to LIF restored the cell counts to untreated levels. LIF reduced the number of cells in S phase. LIF attenuates retinal vascular development in vivo through growth arrest, and not apoptosis, of endothelial cells.
Collapse
Affiliation(s)
- Janet R McColm
- Department of Ophthalmology, University of North Carolina, 6135 Neuroscience Research Building, 103 Mason Farm Road, Chapel Hill, NC 27599-7041, USA.
| | | | | | | |
Collapse
|
13
|
Mutsuga N, Gainer H. Molecular analysis of the magnocellular neuroendocrine phenotype: from the micropunch to laser microdissection. Neurochem Res 2006; 31:189-99. [PMID: 16572260 DOI: 10.1007/s11064-005-9008-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/02/2005] [Indexed: 12/16/2022]
Abstract
Microdissection of selected regions of central nervous system (CNS) has provided the basis of modern chemoarchitectonics. Laser microdissection is a modern variant of the "Palkovits punch" technique and used together with gene array analysis has revolutionalized CNS molecular analysis. Here we describe the use of such an approach to elucidate molecules selectively expressed in magnocellular neuroendocrine cells (MCNs) in the supraoptic nucleus (SON). We found 123 genes that are preferentially expressed in the SON, and of these, 89 were substantially osmoregulated in their expression. One of these, C1q domain containing 1, is a novel gene that is osmoregulated much more than even vasopressin itself.
Collapse
Affiliation(s)
- Noriko Mutsuga
- Molecular Neuroscience Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | | |
Collapse
|
14
|
Zhan X, Desiderio DM. Comparative proteomics analysis of human pituitary adenomas: current status and future perspectives. MASS SPECTROMETRY REVIEWS 2005; 24:783-813. [PMID: 15495141 DOI: 10.1002/mas.20039] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This article will review the published research on the elucidation of the mechanisms of pituitary adenoma formation. Mass spectrometry (MS) plays a key role in those studies. Comparative proteomics has been used with the long-term goal to locate, detect, and characterize the differentially expressed proteins (DEPs) in human pituitary adenomas; to identify tumor-related and -specific biomarkers; and to clarify the basic molecular mechanisms of pituitary adenoma formation. The methodology used for comparative proteomics, the current status of human pituitary proteomics studies, and future perspectives are reviewed. The methodologies that are used in comparative proteomics studies of human pituitary adenomas are readily exportable to other different areas of cancer research.
Collapse
Affiliation(s)
- Xianquan Zhan
- Charles B. Stout Neuroscience Mass Spectrometry Laboratory, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA
| | | |
Collapse
|
15
|
Wang J, Laurie GW. Organogenesis of the exocrine gland. Dev Biol 2004; 273:1-22. [PMID: 15302594 DOI: 10.1016/j.ydbio.2004.05.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2004] [Revised: 04/06/2004] [Accepted: 05/15/2004] [Indexed: 11/16/2022]
Abstract
Morphogenesis of exocrine glands is a complex stepwise process of epithelial ingrowth, ductal elongation, ductal branching, and alveolar or acinar differentiation. Emerging from an increasing number of mouse gene knockout, dominant-negative, and antisense models is the identification of a remarkable collection of cell adhesion molecules, growth factors, and their receptors whose time-dependent contributions to glandular organogenesis are essential. Many have cryptically overlapping and interdependent but noncompensatory roles. Discoidin domain receptor 1 tyrosine kinase (DDR1) and the ErbB1 receptor of amphiregulin are, for example, required for ductal branching and elongation. Each is in turn dependent on the Wnt family of morphogenic factors for autophosphorylation or transactivation, respectively. Here we review the current cast of exocrine glandular morphogens, as a foundation for a global or systems biology appreciation of the interweaving signaling pathways that underlie mammalian glandular morphogenesis.
Collapse
Affiliation(s)
- Jiahu Wang
- Department of Cell Biology, University of Virginia, Charlottesville 22908-0732, USA
| | | |
Collapse
|
16
|
Abbud RA, Kelleher R, Melmed S. Cell-specific pituitary gene expression profiles after treatment with leukemia inhibitory factor reveal novel modulators for proopiomelanocortin expression. Endocrinology 2004; 145:867-80. [PMID: 14576184 DOI: 10.1210/en.2003-0897] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Leukemia inhibitory factor (LIF) mediates the hypothalamo-pituitary-adrenal stress response. Transgenic mice overexpressing LIF in the developing pituitary have altered pituitary differentiation with expansion of corticotropes, maintenance of Rathke's cleft cysts, and suppression of all other pituitary cell types. Affymetrix GeneChips were used to identify modulators of LIF effects in corticotrope (AtT-20) and somatolactotrope (GH(3)) cells. In addition to genes known to respond to LIF in corticotrope cells [e.g. suppressor of cytokine signaling-3 (SOCS-3), signal transducer and activator of transcription-3, SH2 domain-containing tyrosine phosphatase-1, and proopiomelanocortin (POMC)], corticotrope-specific changes were also observed for genes involved in glycolysis and gluconeogenesis, transcription factors, signaling molecules, and expressed sequence tags. Two transcription factors identified, CCAAT/enhancer-binding protein beta (C/EBPbeta) and glial cell-derived neurotrophic factor (GDNF)-inducible factor (GIF), dose-dependently induced expression of the rat POMC promoter when overexpressed in AtT-20 cells. LIF further induced POMC transcription with C/EBPbeta, but not with GIF. C/EBPbeta also induced expression of the SOCS-3 promoter that was further enhanced by cotreatment with LIF. However, GIF did not affect SOCS-3 expression. These results indicate that C/EBPbeta and GIF are downstream effectors of LIF corticotrope action. LIF also stimulates the expression of inhibitors of its actions, such as SOCS-3 and SH2 domain-containing tyrosine phosphatase-1. alpha(2)-HS-glycoprotein (AHSG)/fetuin, a secreted protein that antagonizes bone TGFbeta/bone morphogenic protein signaling, was induced by LIF in a signal transducer and activator of transcription-3-dependent fashion. Pretreatment with AHSG/fetuin blocked LIF-induced expression of the POMC promoter independently of SOCS-3. Thus, using GeneChips, C/EBPbeta and GIF have been identified as novel mediators and AHSG/fetuin as an inhibitor of LIF action in corticotropes.
Collapse
Affiliation(s)
- Rula A Abbud
- Division of Endocrinology, Department of Medicine, Cedars Sinai Medical Center, Los Angeles, CA 90048, USA
| | | | | |
Collapse
|
17
|
Auernhammer CJ, Kopp FB, Vlotides G, Dorn F, Isele NB, Spöttl G, Cengic N, Weber MM, Senaldi G, Engelhardt D. Comparative study of gp130 cytokine effects on corticotroph AtT-20 cells--redundancy or specificity of neuroimmunoendocrine modulators? Neuroimmunomodulation 2004; 11:224-32. [PMID: 15249728 DOI: 10.1159/000078440] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2003] [Accepted: 08/08/2003] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE This comparative in vitro study examined the effects of all known gp130 cytokines on murine corticotroph AtT-20 cell function. METHODS Cytokines were tested at equimolar concentrations from 0.078 to 10 nM. Tyrosine phosphorylation of the signal transducer and activator of transcription (STAT)3 and STAT1, the STAT-dependent suppressor of cytokine signaling (SOCS)-3 promoter activity, SOCS-3 gene expression, STAT-dependent POMC promoter activity and adrenocorticotropic hormone (ACTH) secretion were determined. RESULTS Leukemia inhibitory factor (LIF), human oncostatin M (OSM) and cardiotrophin (CT)-1 (LIFR/gp130 ligands), as well as ciliary neurotrophic factor (CNTF) and novel neurotrophin-1/B-cell stimulating factor-3 (CNTFR alpha/LIFR/gp130 ligands) are potent stimuli of corticotroph cells in vitro. In comparison, interleukin (IL)-6 (IL-6R/gp130 ligand) and IL-11 (IL-11R/gp130 ligand) exhibited only modest direct effects on corticotrophs, while murine OSM (OSMR/gp130 ligand) showed no effect. CONCLUSION (i) CNTFR complex ligands are potent stimuli of corticotroph function, comparable to LIFR complex ligands; (ii) IL-6 and IL-11 are relatively weak direct stimuli of corticotroph function; (iii) differential effects of human and murine OSM suggest that LIFR/gp130 (OSMR type I) but not OSMR/gp130 (OSMR type II) are involved in corticotroph signaling. (iv) CT-1 has the hitherto unknown ability to stimulate corticotroph function, and (v) despite redundant immuno-neuroendocrine effects of different gp130 cytokines, corticotroph cells are preferably activated through the LIFR and CNTFR complexes.
Collapse
MESH Headings
- Adrenocorticotropic Hormone/metabolism
- Animals
- Antigens, CD/drug effects
- Antigens, CD/immunology
- Antigens, CD/metabolism
- Cell Line
- Cytokine Receptor gp130
- Cytokines/immunology
- Cytokines/metabolism
- Cytokines/pharmacology
- DNA-Binding Proteins/drug effects
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Dose-Response Relationship, Drug
- Gene Expression/drug effects
- Gene Expression/immunology
- Hypothalamo-Hypophyseal System/drug effects
- Hypothalamo-Hypophyseal System/immunology
- Leukemia Inhibitory Factor Receptor alpha Subunit
- Ligands
- Membrane Glycoproteins/drug effects
- Membrane Glycoproteins/immunology
- Membrane Glycoproteins/metabolism
- Mice
- Neuroimmunomodulation/immunology
- Phosphorylation/drug effects
- Pituitary Gland, Anterior/cytology
- Pituitary Gland, Anterior/drug effects
- Pituitary Gland, Anterior/immunology
- Pro-Opiomelanocortin/genetics
- Promoter Regions, Genetic/drug effects
- Promoter Regions, Genetic/immunology
- RNA, Messenger/drug effects
- RNA, Messenger/metabolism
- Receptor, Ciliary Neurotrophic Factor/drug effects
- Receptor, Ciliary Neurotrophic Factor/immunology
- Receptor, Ciliary Neurotrophic Factor/metabolism
- Receptors, Cytokine/drug effects
- Receptors, Cytokine/immunology
- Receptors, Cytokine/metabolism
- Receptors, OSM-LIF
- Repressor Proteins/genetics
- STAT1 Transcription Factor
- STAT3 Transcription Factor
- Suppressor of Cytokine Signaling 3 Protein
- Suppressor of Cytokine Signaling Proteins
- Trans-Activators/drug effects
- Trans-Activators/genetics
- Trans-Activators/metabolism
- Transcription Factors/genetics
- Tyrosine/metabolism
Collapse
Affiliation(s)
- Christoph J Auernhammer
- Medizinische Klinik II, Klinikum Grosshadern, Ludwig-Maximilians-Universität, Munich, Germany.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Keegan CE, Camper SA. Mouse knockout solves endocrine puzzle and promotes new pituitary lineage model. Genes Dev 2003; 17:677-82. [PMID: 12651886 DOI: 10.1101/gad.1085903] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Catherine E Keegan
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, MI 48109-0638, USA.
| | | |
Collapse
|
19
|
Nolan LA, Levy A. Temporally sensitive trophic responsiveness of the adrenalectomized rat anterior pituitary to dexamethasone challenge: relationship between mitotic activity and apoptotic sensitivity. Endocrinology 2003; 144:212-9. [PMID: 12488347 DOI: 10.1210/en.2002-220241] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Depending on timing and dose, exogenous glucocorticoids induce a wave of apoptosis in the adult rat anterior pituitary, a response that is enhanced by adrenalectomy. In this study, we show that the size of the glucocorticoid-sensitive apoptotic population progressively increases during the week following surgical adrenalectomy, plateaus for a further week, then spontaneously declines to levels seen in intact animals by 4 wk. Mitotic activity, in contrast, rises rapidly post adrenalectomy but returns to baseline within 2 wk. Increased mitotic activity precedes the increase in the population of cells that undergo glucocorticoid-induced apoptosis and the subsequent decline in mitotic activity precedes the decline in apoptotic sensitivity despite persistent elevation of hypothalamic CRH and pituitary proopiomelanocortin transcripts. If glucocorticoid exposure is delayed until 4 wk post adrenalectomy when the apoptotic response has returned to baseline, glucocorticoid withdrawal, by transiently increasing mitotic activity, again primes the formation of an expanded glucocorticoid-sensitive apoptotic cell population. These data suggest that apoptotic sensitivity is largely confined to cells that have recently entered the cell cycle. This observation is further corroborated by demonstrating an abrupt glucocorticoid-induced step-down in the bromodeoxyuridine-labeling index to basal levels in rats given daily injections of bromodeoxyuridine during the week following adrenalectomy.
Collapse
Affiliation(s)
- L A Nolan
- University Research Center for Neuroendocrinology, University of Bristol, Bristol Royal Infirmary, Bristol BS2 8HW, United Kingdom.
| | | |
Collapse
|
20
|
Chesnokova V, Melmed S. Minireview: Neuro-immuno-endocrine modulation of the hypothalamic-pituitary-adrenal (HPA) axis by gp130 signaling molecules. Endocrinology 2002; 143:1571-4. [PMID: 11956136 DOI: 10.1210/endo.143.5.8861] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The neuroendocrine and immune systems communicate bidirectionally. The neuro-immune-endocrine interface is mediated by cytokines acting as auto/paracrine or endocrine factors regulating pituitary development, cell proliferation, hormone secretion, and feedback control of the hypothalamic-pituitary-adrenal (HPA) axis. At birth or during neonatal ontogenesis, cytokines produce permanent alterations of HPA axis function and the stress response. Overexpressing IL-6 or leukemia inhibitory factor leads to significant changes in pituitary development and functions. Pituitary corticotroph POMC gene expression is regulated by CRH as well as several gp130 cytokines acting as neuro-immuno-endocrine modulators. Conversely, HPA axis functions modulate susceptibility or resistance to inflammatory disease. Cytokines (including IL-1, TNF, and members of the gp130 cytokine family) participate as mediators of a complex HPA axis response to stress and inflammation. Prolonged exposure to proinflammatory cytokines increases levels of the dominant negative glucocorticoid receptor isoform. Nonresponsiveness of the HPA axis to glucocorticoid negative feedback control provides a defense from destructive effects of cytokine excess. At the same time, gp130 cytokines stimulate pituitary suppressor of cytokine signaling (SOCS)-3, which represses cytokine signaling and abrogates cytokine-induced corticotroph POMC gene transcription and ACTH secretion.
Collapse
Affiliation(s)
- Vera Chesnokova
- Cedars-Sinai Research Institute, University of California-Los Angeles School of Medicine, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
| | | |
Collapse
|
21
|
Arzt E. gp130 cytokine signaling in the pituitary gland: a paradigm for cytokine–neuro-endocrine pathways. J Clin Invest 2001. [DOI: 10.1172/jci200114660] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
|
22
|
Arzt E. gp130 cytokine signaling in the pituitary gland: a paradigm for cytokine-neuro-endocrine pathways. J Clin Invest 2001; 108:1729-33. [PMID: 11748253 PMCID: PMC209477 DOI: 10.1172/jci14660] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- E Arzt
- Laboratorio de Fisiología y Biología Molecular, Facultad de Ciencias Exacias y Naturales, Universidad de Buenos Aires and Argentine National Research Council (CONICET), Buenos Aires, Argentina.
| |
Collapse
|
23
|
Tomida M, Yoshida U, Mogi C, Maruyama M, Goda H, Hatta Y, Inoue K. Leukaemia inhibitory factor and interleukin 6 inhibit secretion of prolactin and growth hormone by rat pituitary MtT/SM cells. Cytokine 2001; 14:202-7. [PMID: 11448119 DOI: 10.1006/cyto.2001.0874] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The rat pituitary cell line, MtT/SM, has the characteristics of somatomammotrophs. The cells secrete both prolactin (PRL) and growth hormone (GH). We examined the effects of cytokines such as leukaemia inhibitory factor (LIF), interleukin 6 (IL-6), oncostatin M and interleukin 11 on the secretion of these hormones by the cells. These cytokines stimulate proliferation of the cells and inhibit the secretion of PRL by 70-80% and that of GH by 50%. They induce tyrosine phosphorylation of STAT3 in the cells. The cells containing PRL or GH decreased at 48 h after treatment of the cells with LIF or IL-6. These results suggest that the LIF/IL-6 family of cytokines inhibits the functions of mammotrophs and somatotrophs in the pituitary gland.
Collapse
Affiliation(s)
- M Tomida
- Laboratory of Carcinogenesis and Cancer Prevention, Saitama Cancer Center Research Institute, Ina, Saitama, 362-0806, Japan.
| | | | | | | | | | | | | |
Collapse
|
24
|
Plisov SY, Yoshino K, Dove LF, Higinbotham KG, Rubin JS, Perantoni AO. TGF beta 2, LIF and FGF2 cooperate to induce nephrogenesis. Development 2001; 128:1045-57. [PMID: 11245570 DOI: 10.1242/dev.128.7.1045] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The metanephric kidney develops from interactions between the epithelial ureteric bud and adjacent metanephric mesenchyme, which is induced by the bud to form the epithelia of the nephron. We have found that leukemia inhibitory factor (LIF) and transforming growth factor beta 2 (TGF beta 2) are secreted by inductive rat bud cells and cooperate to enhance and accelerate renal tubule formation in uninduced rat metanephric mesenchymal explants. LIF alone or TGF beta 2 with fibroblast growth factor 2 induced numerous tubules in isolated mesenchymes over an 8 day period, while (in combination) all three caused abundant tubule formation in 72 hours. Furthermore, neutralization of Wnt ligands with antagonist-secreted Frizzled-related protein 1 abrogated these responses and combinatorial cytokine/growth factor stimulation of explants augmented nuclear activation of Tcf1/Lef1, suggesting that LIF and TGF beta 2/FGF2 cooperate to regulate nephrogenesis through a common Wnt-dependent mechanism.
Collapse
Affiliation(s)
- S Y Plisov
- Laboratory of Comparative Carcinogenesis, National Cancer Institute, Frederick, MD 21702, USA
| | | | | | | | | | | |
Collapse
|
25
|
Abstract
A number of primary diseases of the pituitary with adrenocorticotropin dysregulation have been recognized. A few genetic defects have been identified as causes of secondary adrenocortical insufficiency. Much less is known about the ontogeny of corticotrophic tumours leading to a hypercorticolaemic state. To improve the diagnosis and treatment of these disorders, a better understanding of the mechanisms of corticotrophic pituitary cell differentiation and regulation is of clear interest. Studies using molecular tools have enhanced our knowledge over recent years, and a few reports of considerable relevance are summarized in this review.
Collapse
Affiliation(s)
- S Petersenn
- IHF Institute for Hormone and Fertility Research, Hamburg, Germany.
| | | |
Collapse
|
26
|
Pan W, Kastin AJ, Brennan JM. Saturable entry of leukemia inhibitory factor from blood to the central nervous system. J Neuroimmunol 2000; 106:172-80. [PMID: 10814795 DOI: 10.1016/s0165-5728(00)00241-1] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Leukemia inhibitory factor (LIF) is a neurotrophic cytokine now under clinical investigation for its effects on the CNS. We studied its passage across the blood-brain barrier (BBB) from blood to brain and spinal cord. Although a large amount of LIF was reversibly associated with the cerebral vasculature, intact LIF did reach brain parenchyma. Multiple-time regression analysis showed ready access of LIF to the CNS at a rate much faster than that of the vascular marker albumin. Excess LIF inhibited the entry of 125I-LIF after administration i.v. or by in-situ perfusion in blood-free buffer. Efflux of LIF from brain to blood was slower than reabsorption by CSF bulk flow, indicating that LIF tended to be retained in the brain. Although ciliary neurotrophic factor (CNTF) and LIF bind to the same receptor complex, CNTF did not cross-inhibit the entry of LIF into the CNS. A monoclonal antibody to LIF, however, abolished the entry of LIF. Our results show that peripherally administered LIF readily enters the brain and spinal cord by a saturable transport system across the BBB that may have biological implications.
Collapse
Affiliation(s)
- W Pan
- VA Medical Center and Tulane University School of Medicine, New Orleans, LA 70112, USA.
| | | | | |
Collapse
|
27
|
Abstract
Leukemia-inhibitory factor (LIF) is a pleiotropic cytokine expressed by multiple tissue types. The LIF receptor shares a common gp130 receptor subunit with the IL-6 cytokine superfamily. LIF signaling is mediated mainly by JAK-STAT (janus-kinase-signal transducer and activator of transcription) pathways and is abrogated by the SOCS (suppressor-of cytokine signaling) and PIAS (protein inhibitors of activated STAT) proteins. In addition to classic hematopoietic and neuronal actions, LIF plays a critical role in several endocrine functions including the utero-placental unit, the hypothalamo-pituitary-adrenal axis, bone cell metabolism, energy homeostasis, and hormonally responsive tumors. This paper reviews recent advances in our understanding of molecular mechanisms regulating LIF expression and action and also provides a systemic overview of LIF-mediated endocrine regulation. Local and systemic LIF serve to integrate multiple developmental and functional cell signals, culminating in maintaining appropriate hormonal and metabolic homeostasis. LIF thus functions as a critical molecular interface between the neuroimmune and endocrine systems.
Collapse
Affiliation(s)
- C J Auernhammer
- Academic Affairs, Cedars-Sinai Research Institute, University of California Los Angeles School of Medicine, 90048, USA
| | | |
Collapse
|
28
|
Perez Castro C, Nagashima AC, Pereda MP, Goldberg V, Chervin A, Largen P, Renner U, Stalla GK, Arzt E. The gp130 cytokines interleukin-11 and ciliary neurotropic factor regulate through specific receptors the function and growth of lactosomatotropic and folliculostellate pituitary cell lines. Endocrinology 2000; 141:1746-53. [PMID: 10803585 DOI: 10.1210/endo.141.5.7442] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
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.
Collapse
Affiliation(s)
- C Perez Castro
- Department de Biología, FCEN, Universidad de Buenos Aires, Argentina
| | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Abstract
The spatial and proportional representation of the various cell groups in the anterior pituitary is fairly constant, although it may differ between sexes. Recognizable changes occur in a number of physiological and pathological situations. The relative roles of hormones and growth factors in these processes are not fully elucidated, nor are their kinetics. In this paper, published work on basal proliferation, growth factor expression and the growth of specific cell types is reviewed. In addition, we present new data to indicate that the maximum level of proliferation in the anterior pituitary of the male Sprague-Dawley rat occurs around 28 days. We have also demonstrated a circadian rhythm of mitosis in the adult male, with a peak around 1100 h. Cell kinetic analysis suggests a duration for G2 of about 2 hours, and for S phase of 10 1/2 to 11 hours. Finally, we provide data which confirm that the expansion of the corticotroph population after bilateral adrenalectomy is partly the result of an early proliferative response in both corticotrophs and other pituitary cells. Our data also suggest that a further expansion takes place which may reflect differentiation of a population other than committed corticotrophs.
Collapse
Affiliation(s)
- A M McNicol
- University Department of Pathology, Royal Infirmary, Glasgow, UK.
| | | |
Collapse
|
30
|
Pawlikowski M. Endocrine/paracrine control of pituitary cell proliferation and its involvement in pituitary tumorigenesis. Pituitary 1999; 1:251-6. [PMID: 11081205 DOI: 10.1023/a:1009998207652] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The paper concisely reviews the data on the humoral factors which regulate the anterior pituitary cell proliferation in endocrine and/or paracrine manner. Their relevance for pituitary tumorigenesis is also discussed. The role of estrogens, growth factors, neuropeptides, dopamine, interleukins and angiotensins is presented.
Collapse
Affiliation(s)
- M Pawlikowski
- Department of Experimental Endocrinology and Hormone Diagnostics, Medical University of Lodz, Poland
| |
Collapse
|
31
|
Affiliation(s)
- P L Dahia
- Department of Endocrinology, St. Bartholomew's Hospital, London, United Kingdom
| | | |
Collapse
|
32
|
Kim DS, Melmed S. Stimulatory effect of leukemia inhibitory factor on ACTH secretion of dispersed rat pituitary cells. Endocr Res 1999; 25:11-9. [PMID: 10098589 DOI: 10.1080/07435809909066125] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Cytokines are recognized to play an important role in modulating the immune and neuroendocrine system. We recently reported leukemia inhibitory factor (LIF) increased ACTH secretion and pro-opiomelanocortin mRNA level in the murine corticotroph tumor cell line (AtT-20). In this study, the expression of LIF in normal rat pituitary could be demonstrated by ribonuclease protection assay. LIF (1 nM) caused a slight, but significant increase in ACTH secretion (43.7% increase versus control, P<0.01), while showing statistically no significant change of growth hormone and prolactin level in dispersed rat pituitary cells. CRH (10 nM) also induced ACTH secretion 2.5-fold (P<0.01), and co-treatment of LIF and CRH exhibited 2.8-fold increase of ACTH secretion but no statistical difference from CRH treated group. These findings suggest that LIF also has same enhancing effect of ACTH secretion in primary pituitary cultured cells of rat as in AtT-20 cell and LIF acts as a paracrine or autocrine factor to modulate neuroendocrine function in the pituitary.
Collapse
Affiliation(s)
- D S Kim
- Department of Internal Medicine, College of Medicine, Hanyang University, Seoul, Korea
| | | |
Collapse
|
33
|
Abstract
Cytokines are important partners in the bidirectional network interrelating the immune and the neuroendocrine systems. These substances and their specific receptors, initially thought to be exclusively present in the immune system, have recently been shown to be also expressed in the neuroendocrine system. Cytokines can modulate the responses of all endocrine axes by acting at both the central and the peripheral levels. To explain how systemic cytokines may gain access to the brain, several mechanisms have been proposed, including an active transport through the blood-brain barrier, a passage at the circumventricular organ level, as well as a neuronal pathway through the vagal nerve. The immune-neuroendocrine interactions are involved in numerous physiological and pathophysiological conditions and seem to play an important role to maintain homeostasis.
Collapse
Affiliation(s)
- R C Gaillard
- Division of Endocrinology and Metabolism, University Hospital (CHUV), Lausanne/Switzerland
| |
Collapse
|
34
|
Turnbull AV, Rivier CL. Regulation of the hypothalamic-pituitary-adrenal axis by cytokines: actions and mechanisms of action. Physiol Rev 1999; 79:1-71. [PMID: 9922367 DOI: 10.1152/physrev.1999.79.1.1] [Citation(s) in RCA: 808] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Glucocorticoids are hormone products of the adrenal gland, which have long been recognized to have a profound impact on immunologic processes. The communication between immune and neuroendocrine systems is, however, bidirectional. The endocrine and immune systems share a common "chemical language," with both systems possessing ligands and receptors of "classical" hormones and immunoregulatory mediators. Studies in the early to mid 1980s demonstrated that monocyte-derived or recombinant interleukin-1 (IL-1) causes secretion of hormones of the hypothalamic-pituitary-adrenal (HPA) axis, establishing that immunoregulators, known as cytokines, play a pivotal role in this bidirectional communication between the immune and neuroendocrine systems. The subsequent 10-15 years have witnessed demonstrations that numerous members of several cytokine families increase the secretory activity of the HPA axis. Because this neuroendocrine action of cytokines is mediated primarily at the level of the central nervous system, studies investigating the mechanisms of HPA activation produced by cytokines take on a more broad significance, with findings relevant to the more fundamental question of how cytokines signal the brain. This article reviews published findings that have documented which cytokines have been shown to influence hormone secretion from the HPA axis, determined under what physiological/pathophysiological circumstances endogenous cytokines regulate HPA axis activity, established the possible sites of cytokine action on HPA axis hormone secretion, and identified the potential neuroanatomic and pharmacological mechanisms by which cytokines signal the neuroendocrine hypothalamus.
Collapse
Affiliation(s)
- A V Turnbull
- The Clayton Foundation Laboratories for Peptide Biology, The Salk Institute, La Jolla, California, USA
| | | |
Collapse
|
35
|
Savino W, Arzt E, Dardenne M. Immunoneuroendocrine connectivity: the paradigm of the thymus-hypothalamus/pituitary axis. Neuroimmunomodulation 1999; 6:126-36. [PMID: 9876243 DOI: 10.1159/000026372] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
It is now largely established that the immune and neuroendocrine systems cross-talk by using similar ligands and receptors. In this context, the thymus-hypothalamus/pituitary axis can be regarded as a paradigm of connectivity in both normal and pathological conditions. For example, cytokines and thymic hormones modulate hypothalamic-pituitary functions: (a) interleukin (IL)-1 seems to upregulate the production of corticotropin-releasing factor and by adrenocorticotropin by hypothalamic neurons and pituitary cells, respectively; (b) thymulin enhances LH secretion. Conversely, a great deal of data strongly indicate that the hypothalamic-pituitary axis plays a role in the control of thymus physiology. Growth hormone (GH) for example, enhances thymulin secretion by thymic epithelial cells (TEC), both in vivo and in vitro, also increasing extracellular matrix-mediated TEC/thymocyte interactions. Additionally, gap junction-mediated cell coupling among TEC is upregulated by ACTH. In a second vein, it was shown that GH injections in aging mice increased total thymocyte numbers and the percentage of CD3-bearing cells, as well concanavalin-A mitogenic response and IL-6 production. In addition to mutual effects, thymus-pituitary similarities for cytokine and hormone production have been demonstrated. Cytokines such as IL-1, IL-2, IL-6, interferon-gamma, transforming growth factor-beta and others can be produced by hypothalamic and/or pituitary cells. Conversely, hormones including GH, PRL, LH, oxytocin, vasopressin and somatostatin can be produced intrathymically. Moreover, receptors for various cytokines and hormones are expressed in both the thymus and the hypothalamus/pituitary axis. Lastly, it is noteworthy that a thymus-pituitary connectivity can also be seen under pathological situations. In this regard, an altered HPA axis has been reported in AIDS, human falciparum malaria and murine rabies, that also show a severe thymic atrophy.
Collapse
Affiliation(s)
- W Savino
- Laboratory on Thymus Research, Department of Immunology, Institute Oswaldo Cruz, Foundation Oswaldo Cruz, Rio de Janeiro, Brazil.
| | | | | |
Collapse
|
36
|
Arzt E, Pereda MP, Castro CP, Pagotto U, Renner U, Stalla GK. Pathophysiological role of the cytokine network in the anterior pituitary gland. Front Neuroendocrinol 1999; 20:71-95. [PMID: 9882537 DOI: 10.1006/frne.1998.0176] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent evidence has demonstrated that cytokines and other growth factors act in the anterior pituitary gland. Using the traditional criteria employed to determine autocrine or paracrine functions our review shows that, in addition to their role as lymphocyte messengers, certain cytokines are autocrine or paracrine regulators of anterior pituitary function and growth. The cytokines known to regulate and/or be expressed in the anterior pituitary include the inflammatory cytokine family (IL-1 and its endogenous antagonist, IL-1ra; TNF-alpha, and IL-6), the Th1-cytokines (IL-2 and IFN-gamma), and other cytokines such as LIF, MIF, and TGF-beta. This review examines at the cellular, molecular, and physiological levels whether: (1) each cytokine alters some aspect of pituitary physiology; (2) receptors for the cytokine are expressed in the gland; and (3) the cytokine is produced in the anterior pituitary. Should physiological stimuli regulate pituitary cytokine production, this would constitute additional proof of their autocrine/paracrine role. In this context, we analyze in this review the current literature on the actions of cytokines known to regulate anterior pituitary hormone secretion, selecting the in vivo studies that support the direct action of the cytokine in the anterior pituitary. Further support for direct regulatory action is provided by in vitro studies, in explant cultures or pituitary cell lines. The cytokine receptors that have been demonstrated in the pituitary of several species are also discussed. The endogenous production of the homologous cytokines and the regulation of this expression are analyzed. The evidence indicating that cytokines also regulate the growth and proliferation of pituitary cells is reviewed. This action is particularly important since it suggests that intrinsically produced cytokines may play a role in the pathogenesis of pituitary adenomas. The complex cell to cell communication involved in the action of these factors is discussed.
Collapse
Affiliation(s)
- E Arzt
- Dept. de Biología, FCEN, Buenos Aires, Universidad de Buenos Aires, Argentina
| | | | | | | | | | | |
Collapse
|
37
|
Li H, Robinson PJ, Kawashima S, Funder JW, Liu JP. Differential regulation of MAP kinase activity by corticotropin-releasing hormone in normal and neoplastic corticotropes. Int J Biochem Cell Biol 1998; 30:1389-401. [PMID: 9924808 DOI: 10.1016/s1357-2725(98)00093-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Corticotropin-releasing hormone (CRH) plays an important role in regulating the development and function of hypothalamic-pituitary-adrenal axis. The mechanisms by which CRH regulates tissue-specific growth, differentiation and gene expression remain to be established. In the present study, we show that CRH differentially regulates MAP kinase activity in normal ovine anterior pituitary cells and mouse corticotrope AtT20 cells. Incubation of ovine normal anterior pituitary cells with CRH increased MAP kinase activity, an effect mimicked by cAMP and inhibited by the protein kinase A inhibitor H89. In contrast, incubation of mouse pituitary tumor AtT20 cells with CRH inhibited MAP kinase activity, an effect also mimicked by forskolin and inhibited by H89. This decrease in MAP kinase activity occurred with a time course similar to the increase seen in normal anterior pituitary cells. Furthermore, both effects of CRH on MAP kinase activity were inhibited by atrial natriuretic peptide (ANP). ANP also reversed the inhibition of DNA synthesis induced by CRH in AtT20 cells. Thus, CRH may differentially regulate cell growth in sheep normal anterior pituitary and mouse tumor corticotropes by modulating MAP kinase activity through a mechanism dependent on cAMP production and subject to regulation by ANP.
Collapse
Affiliation(s)
- H Li
- Baker Medical Research Institute, Prahran, Vic., Australia.
| | | | | | | | | |
Collapse
|
38
|
Yano H, Readhead C, Nakashima M, Ren SG, Melmed S. Pituitary-directed leukemia inhibitory factor transgene causes Cushing's syndrome: neuro-immune-endocrine modulation of pituitary development. Mol Endocrinol 1998; 12:1708-20. [PMID: 9817597 DOI: 10.1210/mend.12.11.0200] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Leukemia inhibitory factor (LIF) regulates the mature hypothalamic-pituitary-adrenal axis in vivo. In vitro, LIF determines corticotroph cell proliferation and induces POMC transcription. To explore LIF action on pituitary development, transgenic mice expressing LIF driven by the pituitary glycoprotein hormone alpha-subunit (alphaGSU) promoter were generated. Transgenic mice exhibited dwarfism with low IGF-I (29 +/- 9 ng/ml vs. wild type (WT) 137 +/- 16 ng/ml; P < 0.001), hypogonadism with low FSH (0.04 +/- 0.023 ng/ml vs. WT 0.63 +/- 0.18 ng/ml; P < 0.001), and Cushingoid features of thin skin and truncal obesity with elevated cortisol levels (86 +/- 22 ng/ml vs. WT 50 +/- 14 ng/ml; P = 0.002). Their pituitary glands showed corticotroph hyperplasia, striking somatotroph and gonadotroph hypoplasia, and multiple Rathke-like cysts lined by ciliated cells. LIF, overexpressed in Rathke's pouch at embryonal day 10, diverts the differentiation stream of hormone-secreting cells toward the corticotroph lineage and ciliated nasopharyngeal-like epithelium. Thus, inappropriate expression of LIF, a neuro-immune interfacing cytokine, plays a key role in the terminal differentiation events of pituitary development and mature pituitary function.
Collapse
Affiliation(s)
- H Yano
- Department of Medicine, Cedars-Sinai Research Institute, University of California Los Angeles School of Medicine, 90048, USA
| | | | | | | | | |
Collapse
|
39
|
Abstract
Leukemia inhibitory factor (LIF), a pleiotropic cytokine, is expressed in both fetal and adult pituitary tissue, and LIF immunoreactivity is found in functional human pituitary tumors. LIF induces basal, and augments CRH-induced, POMC mRNA and ACTH secretion from AtT20 cells. Therefore, we examined LIF signaling and LIF regulation of POMC expression in AtT20 cells. Immunoneutralization studies demonstrated the dependence of LIF action on both the specific LIF receptor (35% inhibition; p < 0.05) and also the gpl30 affinity converter (41% inhibition; p < 0.05). These antisera also attenuate basal ACTH secretion without added LIF. LIF rapidly induced tyrosyl phosphorylation of both STAT 1 alpha, and STAT beta and also induced phosphorylation of a novel STAT 1 alpha related protein p115. LIF induced POMC transcription (-706/+64) and strikingly potentiated CRH action (up to 18-fold induction). This synergy involved cAMP-dependent pathways, as forskolin action was also potentiated by LIF. Deletion of the major CRH-responsive region in POMC (-323/-166) abolished both CRH and LIF action on POMC transcription. Thus LIF action in pituitary corticotrophs is dependent on LIF receptor heterodimerisation with gpl30 and involves STAT protein tyrosyl phosphorylation. LIF enhances POMC transcription and strongly potentiates the well-documented action of CRH on the POMC gene. These results define a subcellular mechanism for an immuno-neuroendocrine interface between peripheral afferent signals and the HPA axis.
Collapse
Affiliation(s)
- D W Ray
- Department of Medicine, Cedars-Sinai Research Institute-UCLA School of Medicine 90048, USA
| | | | | |
Collapse
|
40
|
Abstract
gp130-Related cytokines such as interleukin-6 and leukemia-inhibitory factor (LIF) act on the adenohypophysis in a paracrine manner, affecting both its differentiation and the function of specific cell types, notably the proopiomelanocortin (POMC) cells. They act on POMC cells in synergism with corticotrophin-releasing hormone, inducing ACTH secretion. gp130-Related cytokines as well as their receptors are expressed in the pituitary. LIF knockout mice show reduced stress-induced ACTH secretion, which can be restored by LIF replacement, suggesting a physiologic role for LIF.
Collapse
Affiliation(s)
- S Melmed
- Cedars-Sinai Research Institute, Department of Endocrinology and Metabolism, UCLA School of Medicine, Los Angeles, CA 90048, USA
| |
Collapse
|
41
|
Li QL, Yano H, Ren SG, Li X, Friedman TC, Melmed S. Leukemia inhibitory factor (LIF) modulates pro-opiomelanocortin (POMC) gene regulation in stably transfected AtT-20 cells overexpressing LIF. Endocrine 1997; 7:325-30. [PMID: 9657069 DOI: 10.1007/bf02801326] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Leukemia inhibitory factor (LIF) levels are elevated in sepsis and correlate with shock and poor prognosis. We have previously shown that lipopolysaccharide (LPS) administration induces hypothalamic and pituitary LIF expression in vivo, which is associated with the acute rise in circulating adrenocorticotrophic hormone (ACTH) levels. As AtT-20 cells respond to LIF, we established murine LIF (mLIF) stably transfected AtT-20 cell lines to study LIF regulation of pro-opiomelanocortin (POMC) expression and ACTH secretion. Our results show that mLIF transfectants accumulated mLIF (up to 15.6 +/- 3.2 ng/mL after 24 h) as well as increased ACTH secretion (up to 2.4-fold above control cells) in conditioned medium. The magnitude of ACTH induction correlated with mLIF concentrations in different transfectants (r = 0.75-0.88, p < 0.05). Moreover, mLIF transfectants showed a higher sensitivity to CRH stimulation with an increased ACTH production within 8 h (p < 0.05), whereas control cells were responsive to CRH at 24 h. Additionally, mLIF transfectants exhibited a maximum threefold ACTH induction, compared to 1.7-fold in control cells. Furthermore, mLIF transfectants have a blunted dexamethasone-mediated inhibition of ACTH (35% inhibition in control cells vs no inhibition in mLIF-transfected cells at 24 h). These findings support and extend the previous observations of LIF acting at the pituitary level, and indicate that mLIF stably-transfected AtT-20 cells are a useful model for studying mLIF-mediated gene regulation in pituicytes.
Collapse
Affiliation(s)
- Q L Li
- Department of Medicine, Cedars-Sinai Research Institute-UCLA School of Medicine, USA
| | | | | | | | | | | |
Collapse
|
42
|
Wang Z, Melmed S. Identification of an upstream enhancer within a functional promoter of the human leukemia inhibitory factor receptor gene and its alternative promoter usage. J Biol Chem 1997; 272:27957-65. [PMID: 9346946 DOI: 10.1074/jbc.272.44.27957] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Knockout of the leukemia inhibitory factor receptor (LIFR) gene results in disrupted placental architecture, imbalanced bone development, and losses of functional neurons. We here report the identification of an enhancer in a functional human LIFR gene promoter and alternative promoter usage by this gene. A single transcription start site was identified in placental JEG-3 cells and a genomic clone containing 4876-nucleotide upstream sequences was found to have promoter activity in JEG-3 cells. However, in osteogenic sarcoma U-2 OS cell, Northern blot using a probe of the first exon detected in JEG-3 cells failed to detect LIFR transcripts. 5'-Rapid amplification of cDNA ends (RACE) revealed an alternative first exon and a 0.6-kilobase pair (kb) 5'-flanking region possessed promoter activity in U-2 OS cells. For the 4.8-kb promoter active in placental cells, a minimal promoter was localized within -162 nucleotides. Three regions increased and one inhibited promoter activity. Subcloning of an activation region (-4876 to -3453 nucleotides) into SV40 promoter either upstream or downstream in either orientation to the luciferase reporter resulted in 10-35-fold luciferase induction, demonstrating the characteristics of an enhancer. Transfections into nine cell lines of different tissue origin indicated that the cloned promoter and enhancer in the 4.8-kb fragment was placental tissue-specific. A 226-base pair fragment (-4625 to -4400 nucleotides) was further localized as the minimal enhancer region, in which deletion of either element A (-4625 to -4581 nucleotides) or element B (-4418 to -4400 nucleotides) resulted in the loss of enhancer activity. Electrophoretic mobility shift assay confirmed that these two elements bind to specific nuclear proteins individually. In the middle region between element A and B, disruption of enhancer integrity also led to a loss of enhancer activity, although two SP1 and three NF-kappaB/c-Rel binding sites did not contribute to enhancer function. These results demonstrate a complex regulation of the human LIFR gene, including alternative promoter usage and tissue-specific elements at the transcription level.
Collapse
Affiliation(s)
- Z Wang
- Cedars Sinai Research Institute-UCLA School of Medicine, Los Angeles, California 90048, USA
| | | |
Collapse
|
43
|
Shimon I, Yan X, Ray DW, Melmed S. Cytokine-dependent gp130 receptor subunit regulates human fetal pituitary adrenocorticotropin hormone and growth hormone secretion. J Clin Invest 1997; 100:357-63. [PMID: 9218512 PMCID: PMC508198 DOI: 10.1172/jci119541] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
We have shown recently that leukemia inhibitory factor (LIF) and oncostatin M (OSM), two members of the gp130-dependent cytokine family, stimulate murine proopiomelanocortin (POMC) transcription and adrenocorticotropin hormone (ACTH) secretion. LIF and corticotropin-releasing hormone (CRH) also synergistically induced in vivo ACTH secretion in fetal nonhuman primates. To elucidate the role of the gp130-related cytokines in human pituitary hormone regulation, we tested expression of gp130-related cytokine receptors in human fetal pituitaries. Using RT-PCR, mRNA expression of receptors for LIF, IL-6, and CRH, and the gp130 subunit, were all detected in fetal pituitaries of 18- and 31-wk gestation. Recombinant human IL-6, LIF, and OSM treatments of primary human fetal pituitary cultures (16-31 wk) increased ACTH secretion by up to 48% (P < 0.05) using doses of 1 nM, and when fetal cultures were cotreated with CRH, ACTH was induced five- to sixfold as compared to CRH alone (three- to fourfold; P = 0.01). Incubation with gp130-specific antibody suppressed basal and cytokine-stimulated ACTH secretion (alone or with CRH) from human fetal cells. Human POMC promoter -879/+6 fused to the luciferase reporter gene and transfected into AtT-20 cells, was stimulated by LIF (7-fold), which also exerted strong (22-fold) synergy with CRH on POMC transcription. Growth hormone (GH) release from fetal cultures was modestly stimulated (15-31%, P < 0.05), while other anterior pituitary hormones were not altered by these cytokines. Thus, physiologic concentrations of the gp130-related cytokines have direct effects on ACTH and GH regulation in the human pituitary, indicating that gp130-dependent signals serve as a paracrine system controlling early human pituitary function.
Collapse
MESH Headings
- Adrenocorticotropic Hormone/metabolism
- Antibodies/immunology
- Antibodies/pharmacology
- Antigens, CD/immunology
- Antigens, CD/metabolism
- Cells, Cultured
- Corticotropin-Releasing Hormone/metabolism
- Cytokine Receptor gp130
- Cytokines/pharmacology
- DNA, Complementary
- Fetus
- Gene Expression Regulation, Developmental
- Growth Inhibitors/pharmacology
- Human Growth Hormone/metabolism
- Humans
- Interleukin-6/pharmacology
- Leukemia Inhibitory Factor
- Lymphokines/pharmacology
- Membrane Glycoproteins/immunology
- Membrane Glycoproteins/metabolism
- Oncostatin M
- Peptides/pharmacology
- Pituitary Gland, Anterior/drug effects
- Pituitary Gland, Anterior/embryology
- Pituitary Gland, Anterior/metabolism
- Pro-Opiomelanocortin/genetics
- RNA, Messenger/analysis
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Transcription, Genetic/drug effects
- Transfection/genetics
Collapse
Affiliation(s)
- I Shimon
- Department of Medicine, Cedars-Sinai Research Institute, UCLA School of Medicine, Los Angeles, California 90048, USA
| | | | | | | |
Collapse
|
44
|
Akita S, Readhead C, Stefaneanu L, Fine J, Tampanaru-Sarmesiu A, Kovacs K, Melmed S. Pituitary-directed leukemia inhibitory factor transgene forms Rathke's cleft cysts and impairs adult pituitary function. A model for human pituitary Rathke's cysts. J Clin Invest 1997; 99:2462-9. [PMID: 9153290 PMCID: PMC508087 DOI: 10.1172/jci119430] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Leukemia inhibitory factor (LIF) and LIF receptors are expressed in adenohypophyseal cells and LIF regulates pituitary hormone transcription and cell replication in vitro. Therefore, transgenic mice expressing pituitary-directed LIF driven by the rat growth hormone (GH) promoter were generated to evaluate the impact of LIF on pituitary development. Three founders were established with diminished linear growth and body weight (57-65% of wild type [WT]), and intense anterior pituitary LIF immunoreactivity. Cystic cavities observed in pituitary anterior lobes were lined by cuboidal, ciliated epithelial cells, focally immunopositive for cytokeratin and S-100 protein and immunonegative for adenohypophyseal hormones. Transgenic pituitaries showed decreased GH (40%) and prolactin (PRL) (26%) cells, and decreased GH and PRL mRNAs by in situ hybridization. ACTH cells increased 2.2-fold, whereas gonadotrophs and thyrotrophs were unchanged. Serum GH was undetectable (< 0.78 ng/ml), PRL levels were one third of WT (P < 0.05), IGF-I levels were 30% of WT (P < 0. 001), and T4 was normal. 10 human pituitary Rathke's cysts studied all showed conclusive LIF immunoreactivity in cyst-lining cells. Thus, intrapituitary murine LIF overexpression causes cystic invaginations from the anterior wall of Rathke's cleft, suggesting failed differentiation of Rathke's epithelium to hormone-secreting cells. Arrested murine pituitary maturation with formation of pituitary Rathke's cleft cysts, GH deficiency, and short stature provide a model to study human Rathke's cyst pathogenesis.
Collapse
Affiliation(s)
- S Akita
- Department of Medicine, Cedars-Sinai Research Institute, University of California, Los Angeles School of Medicine, Los Angeles, California 90048, USA
| | | | | | | | | | | | | |
Collapse
|
45
|
Bousquet C, Ray DW, Melmed S. A common pro-opiomelanocortin-binding element mediates leukemia inhibitory factor and corticotropin-releasing hormone transcriptional synergy. J Biol Chem 1997; 272:10551-7. [PMID: 9099700 DOI: 10.1074/jbc.272.16.10551] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Using murine AtT20 pituitary cells transfected with a rat pro-opiomelanocortin (POMC) promoter (-706/+64) linked to the luciferase reporter, we showed leukemia inhibitory factor (LIF) to strongly potentiate corticotropin-releasing hormone (CRH) induction of POMC gene expression. We therefore tested mechanisms for molecular interactions between LIF and CRH. Although LIF and CRH synergized to induce an 8-fold induction of POMC transcription, CRH alone (but not LIF) induced cAMP response element-binding protein phosphorylation (5-fold) or an increase of c-fos mRNA levels (>100-fold), suggesting that these pathways are not implicated in LIF transcriptional synergistic effects. Using a DNase I footprint assay, POMC promoter regions protected by AtT20 cell nuclear extracts were identified (-121/-109, and -143/-134, and -173/-160). The protected -173/-160 element fused to a heterologous promoter conferred LIF-CRH synergy (6.5-fold induction of POMC) and formed a specific complex with AtT20 cell nuclear extracts. This complex was supershifted by an anti-phosphoserine antibody, and a serine/threonine kinase inhibitor also altered both this complex and LIF-CRH transcriptional synergy on the POMC promoter-luciferase reporter construct, indicating that these events depend on post-translational serine phosphorylations. LIF-CRH synergy on POMC transcription is therefore mediated at least in part by -173/-160 sequences conferring confluent transcriptional activity of both peptides.
Collapse
Affiliation(s)
- C Bousquet
- Department of Medicine, Cedars-Sinai Research Institute-UCLA School of Medicine, Los Angeles, California 90048, USA
| | | | | |
Collapse
|
46
|
Abstract
The complex range of pituitary regulatory mechanisms reviewed here underlies the critical function of the pituitary in sustaining all higher life forms. Thus, the ultimate net secretion of pituitary hormones is determined by signal integration from all three tiers of pituitary control. It is clear from our current knowledge that the trophic hormone cells of the anterior pituitary are uniquely specialized to respond to these signals. Unravelling their diversity and complexity will shed light upon the normal function of the master gland. Understanding these control mechanisms will lead to novel diagnosis and therapy of disordered pituitary function (357).
Collapse
Affiliation(s)
- D Ray
- Cedars-Sinai Research Institute, UCLA School of Medicine 90048-1865, USA
| | | |
Collapse
|