1
|
Ferrari A, Cangini D, Ghelli Luserna di Rorà A, Condorelli A, Pugliese M, Schininà G, Cosentino S, Fonzi E, Domizio C, Simonetti G, Leotta S, Milone G, Martinelli G. Venetoclax durable response in adult relapsed/refractory Philadelphia-negative acute lymphoblastic leukemia with JAK/STAT pathway alterations. Front Cell Dev Biol 2023; 11:1165308. [PMID: 37287455 PMCID: PMC10242111 DOI: 10.3389/fcell.2023.1165308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 05/03/2023] [Indexed: 06/09/2023] Open
Abstract
High-risk relapsed/refractory adult Philadelphia-negative (Ph-) B-cell acute lymphoblastic leukemia (B-ALL) is a great challenge due to limited possibilities to achieve and maintain a complete response. This also applies to cases with extramedullary (EM) involvement that have poor outcomes and no accepted standard therapeutic approaches. The incidence of EM localization in relapsed/refractory B-ALL is poorly investigated: data on patients treated with blinatumomab reported a 40% rate. Some responses were reported in EM patients with relapsed/refractory B-ALL treated with inotuzumab ozogamicin or CAR-T. However, molecular mechanisms of response or refractoriness are usually investigated neither at the medullary nor at EM sites. In the complex scenario of pluri-relapsed/refractory B-ALL patients, new target therapies are needed. Our analysis started with the case of an adult pluri-relapsed Ph- B-ALL patient, poorly sensitive to inotuzumab ozogamicin, donor lymphocyte infusions, and blinatumomab in EM disease, who achieved a durable/complete response after treatment with the BCL2-inhibitor venetoclax. The molecular characterization of medullary and EM samples revealed a tyrosine kinase domain JAK1 mutation in the bone marrow and EM samples at relapse. By comparing the expression level of BCL2- and JAK/STAT pathway-related genes between the patient samples, 136 adult JAK1 wt B-ALL, and 15 healthy controls, we identified differentially expressed genes, including LIFR, MTOR, SOCS1/2, and BCL2/BCL2L1, that are variably modulated at diverse time points and might explain the prolonged response to venetoclax (particularly in the EM site, which was only partially affected by previous therapies). Our results suggest that the deep molecular characterization of both medullary and EM samples is fundamental to identifying effective and personalized targeted therapies.
Collapse
Affiliation(s)
- Anna Ferrari
- Biosciences Laboratory, IRCCS Istituto Romagnolo per lo Studio dei Tumori (IRST) “Dino Amadori”, Meldola, Italy
| | - Delia Cangini
- Hematology Unit, IRCCS Istituto Romagnolo per lo Studio dei Tumori (IRST) “Dino Amadori”, Meldola, Italy
| | - Andrea Ghelli Luserna di Rorà
- Biosciences Laboratory, IRCCS Istituto Romagnolo per lo Studio dei Tumori (IRST) “Dino Amadori”, Meldola, Italy
- Fondazione Pisana per Scienza ONLUS, Pisa, Italy
| | - Annalisa Condorelli
- Divisione di Ematologia con Trapianto Emopoietico—Azienda Ospedaliera Universitaria Policlinico “G. Rodolico- San Marco”, Catania, Italy
| | - Marta Pugliese
- Divisione di Ematologia con Trapianto Emopoietico—Azienda Ospedaliera Universitaria Policlinico “G. Rodolico- San Marco”, Catania, Italy
| | - Giovanni Schininà
- Divisione di Ematologia con Trapianto Emopoietico—Azienda Ospedaliera Universitaria Policlinico “G. Rodolico- San Marco”, Catania, Italy
| | | | - Eugenio Fonzi
- Unit of Biostatistics and Clinical Trials, IRCCS Istituto Romagnolo per lo Studio dei Tumori (IRST) “Dino Amadori”, Meldola, Italy
| | - Chiara Domizio
- Department of Life Sciences and Biotechnology, Ferrara University, Ferrara, Italy
| | - Giorgia Simonetti
- Biosciences Laboratory, IRCCS Istituto Romagnolo per lo Studio dei Tumori (IRST) “Dino Amadori”, Meldola, Italy
| | - Salvatore Leotta
- Divisione di Ematologia con Trapianto Emopoietico—Azienda Ospedaliera Universitaria Policlinico “G. Rodolico- San Marco”, Catania, Italy
| | - Giuseppe Milone
- Divisione di Ematologia con Trapianto Emopoietico—Azienda Ospedaliera Universitaria Policlinico “G. Rodolico- San Marco”, Catania, Italy
| | - Giovanni Martinelli
- Scientific Directorate, IRCCS Istituto Romagnolo per lo Studio dei Tumori (IRST) “Dino Amadori”, Meldola, Italy
| |
Collapse
|
2
|
Yao Y, Bi Z, Wu R, Zhao Y, Liu Y, Liu Q, Wang Y, Wang X. METTL3 inhibits BMSC adipogenic differentiation by targeting the JAK1/STAT5/C/EBPβ pathway via an m 6A-YTHDF2-dependent manner. FASEB J 2019; 33:7529-7544. [PMID: 30865855 DOI: 10.1096/fj.201802644r] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Bone marrow stem cells (BMSCs) are multipotent stem cells that can regenerate mesenchymal tissues, such as adipose tissue, bone, and muscle. Recent studies have shown that N6-methyladenosine (m6A) methylation, one of the most prevalent epigenetic modifications, is involved in the development process. However, whether it plays roles in BMSC differentiation is still elusive. Here, we found that the deletion of m6A "writer" protein methyltransferase-like (METTL)3 in porcine BMSCs (pBMSCs) could promote adipogenesis and janus kinase (JAK)1 protein expression via an m6A-dependent way. Knockdown of METTL3 decreased mRNA m6A levels of JAK1, leading to enhanced YTH m6A RNA binding protein 2 (YTHDF2)-dependent JAK1 mRNA stability. We further demonstrated that JAK1 activated signal transducer and activator of transcription (STAT) 5 through regulation of its phosphorylation to bind to the promoter of CCAAT/enhancer binding protein (C/EBP) β, which could ultimately lead to a modulated adipogenic process. Collectively, our results reveal an orchestrated network linking the m6A methylation and JAK1/STAT5/C/EBPβ pathway in pBMSCs adipogenic differentiation. Our findings provide novel insights into the underlying molecular mechanisms of m6A modification in the regulation of BMSCs differentiating into adipocytes, which may pave a way to develop more effective therapeutic strategies in stem cell regenerative medicine and the treatment of obesity.-Yao, Y., Bi, Z., Wu, R., Zhao, Y., Liu, Y., Liu, Q., Wang, Y., Wang, X. METTL3 inhibits BMSC adipogenic differentiation by targeting the JAK1/STAT5/C/EBPβ pathway via an m6A-YTHDF2-dependent manner.
Collapse
Affiliation(s)
- Yongxi Yao
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Zhen Bi
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Ruifan Wu
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Yuanling Zhao
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Youhua Liu
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Qing Liu
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Yizhen Wang
- College of Animal Sciences, Zhejiang University, Hangzhou, China.,Key Laboratory of Animal Nutrition and Feed Sciences in Eastern China, Ministry of Agriculture, Hangzhou, China
| | - Xinxia Wang
- College of Animal Sciences, Zhejiang University, Hangzhou, China.,Key Laboratory of Animal Nutrition and Feed Sciences in Eastern China, Ministry of Agriculture, Hangzhou, China
| |
Collapse
|
3
|
Shi SY, Luk CT, Brunt JJ, Sivasubramaniyam T, Lu SY, Schroer SA, Woo M. Adipocyte-specific deficiency of Janus kinase (JAK) 2 in mice impairs lipolysis and increases body weight, and leads to insulin resistance with ageing. Diabetologia 2014; 57:1016-26. [PMID: 24531222 DOI: 10.1007/s00125-014-3185-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Accepted: 01/21/2014] [Indexed: 12/14/2022]
Abstract
AIMS/HYPOTHESIS The growing obesity epidemic necessitates a better understanding of adipocyte biology and its role in metabolism. The Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway mediates signalling by numerous cytokines and hormones that regulate adipocyte function, illustrating the physiological importance of adipose JAK-STAT. The aim of this study was to investigate potential roles of adipocyte JAK2, an essential player in the JAK-STAT pathway, in adipocyte biology and metabolism. METHODS We generated adipocyte-specific Jak2 knockout (A-Jak2 KO) mice using the Cre-loxP system with Cre expression driven by the Ap2 (also known as Fabp4) promoter. RESULTS Starting at 2-3 months of age, male and female A-Jak2 KO mice gradually gained more body weight than control littermates primarily due to increased adiposity. This was associated with reduced energy expenditure in A-Jak2 KO mice. In perigonadal adipose tissue, the expression of numerous genes involved in lipid metabolism was differentially regulated. In addition, adipose tissue from A-Jak2 KO mice displayed impaired lipolysis in response to isoprenaline, growth hormone and leptin stimulation, suggesting that adipose JAK2 directly modulates the lipolytic program. Impaired lipid homeostasis was also associated with disrupted adipokine secretion. Accordingly, while glucose metabolism was normal at 2 months of age, by 5-6 months of age, A-Jak2 KO mice had whole-body insulin resistance. CONCLUSIONS/INTERPRETATION Our results suggest that adipocyte JAK2 plays a critical role in the regulation of adipocyte biology and whole-body metabolism. Targeting of the JAK-STAT pathway could be a novel therapeutic option for the treatment of obesity and type 2 diabetes.
Collapse
Affiliation(s)
- Sally Yu Shi
- Toronto General Research Institute, 101 College Street, MaRS Centre/TMDT, Room 10-363, Toronto, ON, Canada, M5G 1L7
| | | | | | | | | | | | | |
Collapse
|
4
|
Park JE, Lee ST, Im WS, Kim M. Growth Hormone Deteriorates the Functional Outcome in an Experimental Model of Huntington's Disease Induced by 3-Nitropionic Acid. J Mov Disord 2013; 6:28-33. [PMID: 24868423 PMCID: PMC4027642 DOI: 10.14802/jmd.13007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 06/14/2013] [Accepted: 08/20/2013] [Indexed: 12/18/2022] Open
Abstract
Background and Purpose: Growth hormone (GH) has been frequently used to control the aging process in healthy individuals, probably due to its slowing effect on senescence-associated degeneration. Mitochondrial dysfunction is related to the aging process, and one of the chemical models of Huntington’s disease is that it can be induced by mitochondrial toxin. To investigate the potential application of GH to modify the progression of Huntington’s disease (HD), we examined whether GH can protect the functional deterioration by striatal damage induced by 3-nitropropionic acid (3NP). Methods: 3NP (63 mg/kg/day) was delivered to Lewis rats by osmotic pumps for five consecutive days, and the rats received intraperitoneal administration of GH or vehicle (saline) throughout the experiment. Neurological deficits and body weight were monitored. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test was performed to further determine the mitochondrial activity in cultured N18TG2 neuroblastoma cells in vitro. Results: 3NP-treated rats showed progressive neurologic deficits with striatal damage. Application of GH accelerated behavioral deterioration, particularly between day 3 and day 5, resulting in reduced survival outcome. The body weights of rats given 3NP were decreased, but GH did not affect such decrease compared to the non-treated control group. The effect of GH on cultured neuronal cells was a decrease in the MTT absorbance, suggesting a lower number of cells in a dose dependent pattern. Conclusions: Those results suggest that application of GH to a 3NP-induced experimental model of HD deteriorates the progress of functional deficits, possibly disturbing mitochondrial activities.
Collapse
Affiliation(s)
- Jung-Eun Park
- Department of Neurology, Clinical Research Institute, Seoul National University Hospital, Seoul, Korea ; Program in Neuroscience, Seoul National University, Seoul, Korea
| | - Soon-Tae Lee
- Department of Neurology, Clinical Research Institute, Seoul National University Hospital, Seoul, Korea ; Program in Neuroscience, Seoul National University, Seoul, Korea
| | - Woo-Seok Im
- Department of Neurology, Clinical Research Institute, Seoul National University Hospital, Seoul, Korea
| | - Manho Kim
- Department of Neurology, Clinical Research Institute, Seoul National University Hospital, Seoul, Korea ; Program in Neuroscience, Seoul National University, Seoul, Korea
| |
Collapse
|
5
|
Radi Z, Bartholomew P, Elwell M, Vogel WM. Comparative pathophysiology, toxicology, and human cancer risk assessment of pharmaceutical-induced hibernoma. Toxicol Appl Pharmacol 2013; 273:456-63. [PMID: 24141031 DOI: 10.1016/j.taap.2013.10.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 10/05/2013] [Accepted: 10/09/2013] [Indexed: 01/26/2023]
Abstract
In humans, hibernoma is a very rare, benign neoplasm of brown adipose tissue (BAT) that typically occurs at subcutaneous locations and is successfully treated by surgical excision. No single cause has been accepted to explain these very rare human tumors. In contrast, spontaneous hibernoma in rats is rare, often malignant, usually occurs in the thoracic or abdominal cavity, and metastases are common. In recent years, there has been an increased incidence of spontaneous hibernomas in rat carcinogenicity studies, but overall the occurrence remains relatively low and highly variable across studies. There have only been four reported examples of pharmaceutical-induced hibernoma in rat carcinogenicity studies. These include phentolamine, an alpha-adrenergic antagonist; varenicline, a nicotine partial agonist; tofacitinib, a Janus kinase (JAK) inhibitor; and hydromorphone, an opiod analgesic. Potential non-genotoxic mechanisms that may contribute to the pathogenesis of BAT activation/proliferation and/or subsequent hibernoma development in rats include: (1) physiological stimuli, (2) sympathetic stimulation, (3) peroxisome proliferator-activated receptor (PPAR) agonism, and/or (4) interference or inhibition of JAK/Signal Transducer and Activator of Transcription (JAK/STAT) signaling. The evaluation of an apparent increase of hibernoma in rats from 2-year carcinogenicity studies of novel pharmaceutical therapeutics and its relevance to human safety risk assessment is complex. One should consider: the genotoxicity of the test article, dose/exposure and safety margins, and pathophysiologic and morphologic differences and similarities of hibernoma between rats and humans. Hibernomas observed to date in carcinogenicity studies of pharmaceutical agents do not appear to be relevant for human risk at therapeutic dosages.
Collapse
Affiliation(s)
- Zaher Radi
- Pfizer Worldwide Research and Development, Drug Safety R&D, 1 Burtt Rd., Andover, MA 01810, USA.
| | | | | | | |
Collapse
|
6
|
The role of JAK-STAT signaling in adipose tissue function. Biochim Biophys Acta Mol Basis Dis 2013; 1842:431-9. [PMID: 23735217 DOI: 10.1016/j.bbadis.2013.05.030] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 05/20/2013] [Accepted: 05/22/2013] [Indexed: 01/14/2023]
Abstract
Adipocytes play important roles in lipid storage, energy homeostasis and whole body insulin sensitivity. The JAK-STAT (Janus Kinase-Signal Transducer and Activator of Transcription) pathway mediates a variety of physiological processes including development, hematopoiesis, and inflammation. Although the JAK-STAT signaling pathway occurs in all cells, this pathway can mediate cell specific responses. Studies in the last two decades have identified hormones and cytokines that activate the JAK-STAT signaling pathway. These cytokines and hormones have profound effects on adipocytes. The content of this review will introduce the types of adipocytes and immune cells that make up adipose tissue, the impact of obesity on adipose cellular composition and function, and the general constituents of the JAK-STAT pathway and how its activators regulate adipose tissue development and physiology. A summary of the identification of STAT target genes in adipocytes reveals how these transcription factors impact various areas of adipocyte metabolism including insulin action, modulation of lipid stores, and glucose homeostasis. Lastly, we will evaluate exciting new data linking the JAK-STAT pathway and brown adipose tissue and consider the future outlook in this area of investigation. This article is part of a Special Issue entitled: Modulation of Adipose Tissue in Health and Disease.
Collapse
|
7
|
Richard AJ, Stephens JM. Emerging roles of JAK-STAT signaling pathways in adipocytes. Trends Endocrinol Metab 2011; 22:325-32. [PMID: 21561789 PMCID: PMC3149764 DOI: 10.1016/j.tem.2011.03.007] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 03/16/2011] [Accepted: 03/30/2011] [Indexed: 01/14/2023]
Abstract
Twenty years ago, adipocytes were largely considered to be inert energy-storage depots. We now know that fat cells are highly insulin-sensitive with significant endocrine functions. Alterations in adipocyte development or function can contribute to metabolic disease, in particular type 2 diabetes. The current obesity epidemic that plagues many nations provides a strong rationale for understanding basic adipocyte biology. The JAK-STAT signaling pathway mediates the action of a variety of hormones that have profound effects on adipocyte development and function. In addition, adipocytes secrete hormones that utilize this signaling pathway. This review summarizes research on the expression and function of JAKs and STATs in adipocytes and highlights the roles of JAK-STAT-activating cytokines in adipose tissue.
Collapse
Affiliation(s)
| | - Jacqueline M. Stephens
- To whom correspondence should be addressed, Louisiana State University, Department of Biological Sciences, 202 Life Sciences Bldg., Baton Rouge, LA 70803, Phone (225)-578-1749, FAX (225)-578-2597,
| |
Collapse
|
8
|
Lyuh E, Kim HJ, Kim M, Lee JK, Park KS, Yoo KY, Lee KW, Ahn YO. Dose-specific or dose-dependent effect of growth hormone treatment on the proliferation and differentiation of cultured neuronal cells. Growth Horm IGF Res 2007; 17:315-322. [PMID: 17482859 DOI: 10.1016/j.ghir.2007.03.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2006] [Revised: 03/11/2007] [Accepted: 03/21/2007] [Indexed: 12/12/2022]
Abstract
OBJECTIVE GH controls the proliferation of cartilage, fibroblasts or the differentiation of adipose and muscle tissue. However, the effect of GH on neuronal cells remains unknown. The present study was conducted to determine the proliferative or differentiating effect of GH on the nervous system in vitro. DESIGN Neuronal hybrid cells (VSC4.1) were cultured with GH. The concentration ranged from 0.134 microg/ml up to 1.34 mg/ml. A cell confluency and MTT assay, cell cycle phase analysis with flow cytometry, extracellular receptor kinase (ERK) phosphorylation and mitogen activated protein kinase (MAPK) inhibitor (PD98050) assays were all performed to determine the effect on proliferation. Differentiation was evaluated by neurite outgrowth and neurofilament expression. Terminally differentiated neurons were stained by Hoechst 33342 for apoptotic nuclear fragmentation by degeneration. Poly-adenosyl ribose polymerase (PARP) expression and its cleavage products were evaluated. RESULTS Cells at concentrations between 0.134 microg/ml and 1.34 microg/ml of GH proliferated with ERK phosphorylation, which was attenuated by MAPK inhibitors. Proliferation decreased at concentrations higher than 13.4 microg/ml; however, neurite outgrowth was observed at these concentrations. Terminally differentiated cells underwent apoptosis and showed nuclear fragmentation by Hoechst 33342 staining. PARP expression was increased with caspase-3 dependent-cleaved fragment. CONCLUSIONS Our in vitro data demonstrate that GH exerts dual effects; proliferation with a specific GH dose window, or differentiation in a dose-dependent manner in cultured neuronal hybrid cells.
Collapse
Affiliation(s)
- Esther Lyuh
- Department of Preventive Medicine, Seoul National University, Esther Clinic, Seoul 110-744, Republic of Korea
| | | | | | | | | | | | | | | |
Collapse
|
9
|
Adriani M, Garbi C, Amodio G, Russo I, Giovannini M, Amorosi S, Matrecano E, Cosentini E, Candotti F, Pignata C. Functional Interaction of Common γ-Chain and Growth Hormone Receptor Signaling Apparatus. THE JOURNAL OF IMMUNOLOGY 2006; 177:6889-95. [PMID: 17082603 DOI: 10.4049/jimmunol.177.10.6889] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We previously reported on an X-linked SCID (X-SCID) patient, who also had peripheral growth hormone (GH) hyporesponsiveness and abnormalities of the protein phosphorylation events following GH receptor (GHR) stimulation. In the present study, we examined a potential role of common cytokine receptor gamma-chain (gammac) in GHR signaling using EBV-transformed lymphocytes from healthy subjects and gammac-negative X-SCID patients. We demonstrated that the proliferative response to GH stimulation of the B cell lines of gammac-negative patients was impaired despite a comparable cellular expression of GHR molecules to controls. In patients, after GH stimulation, no phosphorylation of STAT5 was observed. In addition, the molecule localization through confocal microscopy revealed that in B cell lines of patients no nuclear translocation of STAT5b following GH stimulation occurred differently from controls. Biochemical analysis of the nuclear extracts of gammac-negative cell lines provided further evidence that the amount of STAT5b and its phosphorylated form did not increase following GH stimulation. In patients, cells reconstituted with wild-type gammac abnormal biochemical and functional events were restored resulting in nuclear translocation of STAT5. Confocal experiments revealed that GHR and gammac were colocalized on the cell membrane. Our study demonstrates the existence of a previously unappreciated relationship between GHR-signaling pathway and gammac, which is required for the activation of STAT5b in B cell lines. These data also confirm that growth failure in X-SCID is primarily related to the genetic alteration of the IL2RG gene.
Collapse
|
10
|
Schäffler A, Schölmerich J, Buechler C. The role of 'adipotropins' and the clinical importance of a potential hypothalamic–pituitary–adipose axis. ACTA ACUST UNITED AC 2006; 2:374-83. [PMID: 16932320 DOI: 10.1038/ncpendmet0197] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2005] [Accepted: 02/09/2006] [Indexed: 01/17/2023]
Abstract
Since adipocytes express specific receptors for pituitary hormones and hypothalamic releasing factors, adipose tissue has to be regarded as a fast-acting endocrine gland under the control of the brain. Expanding on this suggestion, the existence and clinical impact of a hypothalamic-pituitary-adipose axis is reviewed. The term 'adipotropins' is introduced in order to describe pituitary and hypothalamic hormones or releasing factors that directly target adipocytes by their specific receptors.
Collapse
Affiliation(s)
- Andreas Schäffler
- Department of Internal Medicine I, University of Regensburg, Germany.
| | | | | |
Collapse
|
11
|
Zhou Y, Wang X, Hadley J, Corey SJ, Vasilatos-Younken R. Regulation of JAK2 protein expression by chronic, pulsatile GH administration in vivo: a possible mechanism for ligand enhancement of signal transduction. Gen Comp Endocrinol 2005; 144:128-39. [PMID: 15993410 DOI: 10.1016/j.ygcen.2005.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2004] [Revised: 04/28/2005] [Accepted: 05/02/2005] [Indexed: 10/25/2022]
Abstract
Growth hormone (GH) is a key factor controlling postnatal growth and development. Despite growth-promoting effects in mammals, GH is not associated with muscle growth in the chicken. Janus kinase 2 (JAK2) has been identified as the first intracellular step in GH receptor (GHR) signaling in many species, however, there is limited knowledge regarding the GH signaling pathway in the chicken. In this study, GH-responsive, JAK2 immunoreactive proteins were first assessed in an avian hepatoma cell line (LMH). Tyrosine phosphorylation of a 120-122 kDa JAK2 immunoreactive protein was GH dose-dependent. In addition to in vitro studies, the timecourse of JAK2 activation in liver and skeletal muscle (Pectoralis superficialis) in response to a single intravenous (i.v.) injection of chicken GH (cGH), and the effect of chronic exposure to GH in a physiologically relevant pattern on JAK2 protein expression and tyrosine phosphorylation in vivo were assessed. At a dose of GH that was previously demonstrated to elicit a maximal metabolic response (6.25 microg/kg BW), maximum tyrosine phosphorylation of JAK2 appeared at 10 min post-GH administration in the pectoralis muscle, but was not detectable in liver. To assess whether chronic enhancement of GH would alter expression of JAK2, we utilized a dynamic model of pulsatile GH infusion that mimicked the early pattern of circulating GH expressed in younger, rapidly growing birds (high amplitude peaks with an inter-peak interval of 90 min). A 120-122 kDa protein in liver and muscle, and a dominant 130-136 kDa protein in the muscle, that was phosphorylated in response to GH, were specifically recognized by the JAK2 antibody. Chronic, pulsatile infusion of cGH into 8-week-old chickens was associated with increased abundance and tyrosine phosphorylation of JAK2 protein in both liver and muscle (P < 0.05), which were GH dose-dependent, and mirrored previously reported biological responses for the same birds [Vasilatos-Younken, R., Zhou, Y., Wang, X., McMurtry, J.P., Rosebrough, R.W., Decuypere, E., Buys, N., Darras, V.M., Van Der Geyten, S., Tomas, F., 2000. Altered chicken thyroid hormone metabolism with chronic GH enhancement in vivo: Consequences for skeletal muscle growth. Journal of Endocrinology 166, 609-620.]. In summary (1) JAK2 immunoreactive proteins that associate with the GHR and are tyrosine phosphorylated in response to GH were identified in an avian hepatoma cell line and expressed in both GH responsive (liver) and "non-responsive" (skeletal muscle) tissues; (2) tyrosine phosphorylation of JAK2 occurred within minutes of exposure to a single i.v. injection of GH in vivo in muscle but not liver of 8-week-old birds; and 3) there were GH dose-dependent increases in abundance of JAK2 protein and tyrosine phosphorylation in both tissues when chronically exposed to GH in a physiologically relevant pattern, that mirrored dose-dependent biological responses, including alterations in the pathway of thyroid hormone metabolism, previously reported. Enhanced JAK2 suggests one possible mechanism whereby chronic, physiologically appropriate exposure to the ligand enhances GH biological action via increased abundance of a key upstream component of the signal transduction pathway.
Collapse
Affiliation(s)
- Yuan Zhou
- Department of Poultry Science, The Pennsylvania State University, University Park, 16802, USA
| | | | | | | | | |
Collapse
|
12
|
Louveau I, Gondret F. Regulation of development and metabolism of adipose tissue by growth hormone and the insulin-like growth factor system. Domest Anim Endocrinol 2004; 27:241-55. [PMID: 15451072 DOI: 10.1016/j.domaniend.2004.06.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2004] [Accepted: 06/21/2004] [Indexed: 01/19/2023]
Abstract
White adipose tissue plays a key role in the regulation of the energy balance of vertebrates. This tissue is also now recognized to secrete a variety of factors such as leptin, which is thought to be involved in the modulation of adipose mass. Unlike other tissues, adipose tissue mass has considerable capacity to expand. The review deals primarily on the regulation of development and metabolism of adipose tissue by growth hormone (GH) and the insulin-like growth factor (IGF) system, with a special focus on the pig. The anti-insulin effects of GH are well-documented in pigs as in other species. In vitro exposure of adipose precursor cells to GH leads to a decrease in differentiation of those cells in pigs, in contrast to data obtained in murine cell lines. In vivo treatment and prolonged in vitro incubation of adipose tissue or isolated adipocytes with GH result in a decrease in glucose transport and lipogenesis, especially at the level of the fatty acid synthase gene, resulting in a reduction of the lipid content and adipose tissue mass. The mechanism by which GH antagonizes insulin stimulation of lipogenesis is still unresolved, as it is not mediated by protein kinase A, protein kinase C and Janus kinase-2 at the signaling level, or upstream stimulatory factor 1 or sterol regulatory element binding protein-1 at the transcriptional level. GH is apparently the main regulator of IGF-I mRNA expression in adipose tissue, however, the effects of IGF-I on this tissue are rather unclear.
Collapse
Affiliation(s)
- I Louveau
- Institut National de la Recherche Agronomique, Unité Mixte de Recherches sur le Veau et le Porc, 35590 Saint Gilles, France.
| | | |
Collapse
|
13
|
Hansen TK. Pharmacokinetics and acute lipolytic actions of growth hormone. Impact of age, body composition, binding proteins, and other hormones. Growth Horm IGF Res 2002; 12:342-358. [PMID: 12213188 DOI: 10.1016/s1096-6374(02)00061-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The biologic actions of endogeneous growth hormone (GH) depend on its secretion and clearance rates as well as sensitivity at the receptor level. Aberrations in GH pharmacokinetics and pharmacodynamics may occur with increasing age, and have been implicated in diseases such as obesity, diabetes mellitus, and critical illness. In this review, recent insights into the association between GH metabolism and age, body composition, binding proteins and other hormones are discussed.
Collapse
Affiliation(s)
- Troels Krarup Hansen
- Medical Department M (Endocrinology and Diabetes) Aarhus University Hospital, DK-8000 Aarhus C, Denmark.
| |
Collapse
|