1
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Churilov AN, Milton JG. Modeling pulsativity in the hypothalamic-pituitary-adrenal hormonal axis. Sci Rep 2022; 12:8480. [PMID: 35589935 PMCID: PMC9120490 DOI: 10.1038/s41598-022-12513-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 05/04/2022] [Indexed: 11/18/2022] Open
Abstract
A new mathematical model for biological rhythms in the hypothalamic–pituitary–adrenal (HPA) axis is proposed. This model takes the form of a system of impulsive time-delay differential equations which include pulsatile release of adrenocorticotropin (ACTH) by the pituitary gland and a time delay for the release of glucocorticoid hormones by the adrenal gland. Numerical simulations demonstrate that the model’s response to periodic and circadian inputs from the hypothalamus are consistent with those generated by recent models which do not include a pulsatile pituitary. In contrast the oscillatory phenomena generated by the impulsive delay equation mode occur even if the time delay is zero. The observation that the time delay merely introduces a small phase shift suggesting that the effects of the adrenal gland are “downstream” to the origin of pulsativity. In addition, the model accounts for the occurrence of ultradian oscillations in an isolated pituitary gland. These observations suggest that principles of pulse modulated control, familiar to control engineers, may have an increasing role to play in understanding the HPA axis.
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Affiliation(s)
- Alexander N Churilov
- Faculty of Mathematics and Mechanics, Saint Petersburg State University, Saint Petersburg, Russia
| | - John G Milton
- W. M. Keck Science Center, The Claremont Colleges, Claremont, CA, USA.
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2
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Guérineau NC, Campos P, Le Tissier PR, Hodson DJ, Mollard P. Cell Networks in Endocrine/Neuroendocrine Gland Function. Compr Physiol 2022; 12:3371-3415. [PMID: 35578964 DOI: 10.1002/cphy.c210031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Reproduction, growth, stress, and metabolism are determined by endocrine/neuroendocrine systems that regulate circulating hormone concentrations. All these systems generate rhythms and changes in hormone pulsatility observed in a variety of pathophysiological states. Thus, the output of endocrine/neuroendocrine systems must be regulated within a narrow window of effective hormone concentrations but must also maintain a capacity for plasticity to respond to changing physiological demands. Remarkably most endocrinologists still have a "textbook" view of endocrine gland organization which has emanated from 20th century histological studies on thin 2D tissue sections. However, 21st -century technological advances, including in-depth 3D imaging of specific cell types have vastly changed our knowledge. We now know that various levels of multicellular organization can be found across different glands, that organizational motifs can vary between species and can be modified to enhance or decrease hormonal release. This article focuses on how the organization of cells regulates hormone output using three endocrine/neuroendocrine glands that present different levels of organization and complexity: the adrenal medulla, with a single neuroendocrine cell type; the anterior pituitary, with multiple intermingled cell types; and the pancreas with multiple intermingled cell types organized into distinct functional units. We give an overview of recent methodologies that allow the study of the different components within endocrine systems, particularly their temporal and spatial relationships. We believe the emerging findings about network organization, and its impact on hormone secretion, are crucial to understanding how homeostatic regulation of endocrine axes is carried out within endocrine organs themselves. © 2022 American Physiological Society. Compr Physiol 12:3371-3415, 2022.
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Affiliation(s)
| | - Pauline Campos
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
| | - Paul R Le Tissier
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, Scotland, UK
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Edgbaston, UK.,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK.,COMPARE University of Birmingham and University of Nottingham Midlands, UK.,Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Patrice Mollard
- IGF, University of Montpellier, CNRS, INSERM, Montpellier, France
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3
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Grant AD, Wilbrecht L, Kriegsfeld LJ. Adolescent Development of Biological Rhythms in Female Rats: Estradiol Dependence and Effects of Combined Contraceptives. Front Physiol 2021; 12:752363. [PMID: 35615288 PMCID: PMC9126190 DOI: 10.3389/fphys.2021.752363] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 10/11/2021] [Indexed: 01/23/2023] Open
Abstract
Adolescence is a period of continuous development, including the maturation of endogenous rhythms across systems and timescales. Although, these dynamic changes are well-recognized, their continuous structure and hormonal dependence have not been systematically characterized. Given the well-established link between core body temperature (CBT) and reproductive hormones in adults, we hypothesized that high-resolution CBT can be applied to passively monitor pubertal development and disruption with high fidelity. To examine this possibility, we used signal processing to investigate the trajectory of CBT rhythms at the within-day (ultradian), daily (circadian), and ovulatory timescales, their dependence on estradiol (E2), and the effects of hormonal contraceptives. Puberty onset was marked by a rise in fecal estradiol (fE2), followed by an elevation in CBT and circadian power. This time period marked the commencement of 4-day rhythmicity in fE2, CBT, and ultradian power marking the onset of the estrous cycle. The rise in circadian amplitude was accelerated by E2 treatment, indicating a role for this hormone in rhythmic development. Contraceptive administration in later adolescence reduced CBT and circadian power and resulted in disruption to 4-day cycles that persisted after discontinuation. Our data reveal with precise temporal resolution how biological rhythms change across adolescence and demonstrate a role for E2 in the emergence and preservation of multiscale rhythmicity. These findings also demonstrate how hormones delivered exogenously in a non-rhythmic pattern can disrupt rhythmic development. These data lay the groundwork for a future in which temperature metrics provide an inexpensive, convenient method for monitoring pubertal maturation and support the development of hormone therapies that better mimic and support human chronobiology.
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Affiliation(s)
- Azure D. Grant
- The Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
| | - Linda Wilbrecht
- The Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
- Department of Psychology, University of California, Berkeley, Berkeley, CA, United States
| | - Lance J. Kriegsfeld
- The Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
- Department of Psychology, University of California, Berkeley, Berkeley, CA, United States
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, United States
- Graduate Group in Endocrinology, University of California, Berkeley, Berkeley, CA, United States
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4
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Androulakis IP. Circadian rhythms and the HPA axis: A systems view. WIREs Mech Dis 2021; 13:e1518. [PMID: 33438348 DOI: 10.1002/wsbm.1518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 11/20/2020] [Accepted: 11/30/2020] [Indexed: 12/26/2022]
Abstract
The circadian timing system comprises a network of time-keeping clocks distributed across a living host whose responsibility is to allocate resources and distribute functions temporally to optimize fitness. The molecular structures generating these rhythms have evolved to accommodate the rotation of the earth in an attempt to primarily match the light/dark periods during the 24-hr day. To maintain synchrony of timing across and within tissues, information from the central clock, located in the suprachiasmatic nucleus, is conveyed using systemic signals. Leading among those signals are endocrine hormones, and while the hypothalamic-pituitary-adrenal axis through the release of glucocorticoids is a major pacesetter. Interestingly, the fundamental units at the molecular and physiological scales that generate local and systemic signals share critical structural properties. These properties enable time-keeping systems to generate rhythmic signals and allow them to adopt specific properties as they interact with each other and the external environment. The purpose of this review is to provide a broad overview of these structures, discuss their functional characteristics, and describe some of their fundamental properties as these related to health and disease. This article is categorized under: Immune System Diseases > Computational Models Immune System Diseases > Biomedical Engineering.
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Affiliation(s)
- Ioannis P Androulakis
- Biomedical Engineering Department, Chemical & Biochemical Engineering Department, Rutgers University, New Brunswick, New Jersey.,Department of Surgery, Rutgers-Robert Wood Johnson Medical School, New Brunswick, New Jersey, USA
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Zavala E, Voliotis M, Zerenner T, Tabak J, Walker JJ, Li XF, Terry JR, Lightman SL, O'Byrne K, Tsaneva-Atanasova K. Dynamic Hormone Control of Stress and Fertility. Front Physiol 2020; 11:598845. [PMID: 33329048 PMCID: PMC7718016 DOI: 10.3389/fphys.2020.598845] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 10/20/2020] [Indexed: 12/13/2022] Open
Abstract
Neuroendocrine axes display a remarkable diversity of dynamic signaling processes relaying information between the brain, endocrine glands, and peripheral target tissues. These dynamic processes include oscillations, elastic responses to perturbations, and plastic long term changes observed from the cellular to the systems level. While small transient dynamic changes can be considered physiological, larger and longer disruptions are common in pathological scenarios involving more than one neuroendocrine axes, suggesting that a robust control of hormone dynamics would require the coordination of multiple neuroendocrine clocks. The idea of apparently different axes being in fact exquisitely intertwined through neuroendocrine signals can be investigated in the regulation of stress and fertility. The stress response and the reproductive cycle are controlled by the Hypothalamic-Pituitary-Adrenal (HPA) axis and the Hypothalamic-Pituitary-Gonadal (HPG) axis, respectively. Despite the evidence surrounding the effects of stress on fertility, as well as of the reproductive cycle on stress hormone dynamics, there is a limited understanding on how perturbations in one neuroendocrine axis propagate to the other. We hypothesize that the links between stress and fertility can be better understood by considering the HPA and HPG axes as coupled systems. In this manuscript, we investigate neuroendocrine rhythms associated to the stress response and reproduction by mathematically modeling the HPA and HPG axes as a network of interlocked oscillators. We postulate a network architecture based on physiological data and use the model to predict responses to stress perturbations under different hormonal contexts: normal physiological, gonadectomy, hormone replacement with estradiol or corticosterone (CORT), and high excess CORT (hiCORT) similar to hypercortisolism in humans. We validate our model predictions against experiments in rodents, and show how the dynamic responses of these endocrine axes are consistent with our postulated network architecture. Importantly, our model also predicts the conditions that ensure robustness of fertility to stress perturbations, and how chronodisruptions in glucocorticoid hormones can affect the reproductive axis' ability to withstand stress. This insight is key to understand how chronodisruption leads to disease, and to design interventions to restore normal rhythmicity and health.
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Affiliation(s)
- Eder Zavala
- Centre for Systems Modelling and Quantitative Biomedicine, University of Birmingham, Birmingham, United Kingdom
- Institute of Metabolism and Systems Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Margaritis Voliotis
- EPSRC Centre for Predictive Modelling in Healthcare, Living Systems Institute, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, United Kingdom
| | - Tanja Zerenner
- EPSRC Centre for Predictive Modelling in Healthcare, Living Systems Institute, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, United Kingdom
| | - Joël Tabak
- Institute of Biomedical and Clinical Science, College of Medicine and Health, University of Exeter, Exeter, United Kingdom
| | - Jamie J. Walker
- EPSRC Centre for Predictive Modelling in Healthcare, Living Systems Institute, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, United Kingdom
- Henry Wellcome Laboratory for Integrative Neuroscience and Endocrinology, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Xiao Feng Li
- Department of Women and Children's Health, School of Life Course Sciences, King's College London, London, United Kingdom
| | - John R. Terry
- Centre for Systems Modelling and Quantitative Biomedicine, University of Birmingham, Birmingham, United Kingdom
- Institute of Metabolism and Systems Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Stafford L. Lightman
- Henry Wellcome Laboratory for Integrative Neuroscience and Endocrinology, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Kevin O'Byrne
- Department of Women and Children's Health, School of Life Course Sciences, King's College London, London, United Kingdom
| | - Krasimira Tsaneva-Atanasova
- EPSRC Centre for Predictive Modelling in Healthcare, Living Systems Institute, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, United Kingdom
- Department of Bioinformatics and Mathematical Modelling, Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
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Churilov AN, Milton J, Salakhova ER. An integrate-and-fire model for pulsatility in the neuroendocrine system. CHAOS (WOODBURY, N.Y.) 2020; 30:083132. [PMID: 32872840 DOI: 10.1063/5.0010553] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 07/08/2020] [Indexed: 06/11/2023]
Abstract
A model for pulsatility in neuroendocrine regulation is proposed which combines Goodwin-type feedback control with impulsive input from neurons located in the hypothalamus. The impulsive neural input is modeled using an integrate-and-fire mechanism; namely, inputs are generated only when the membrane potential crosses a threshold, after which it is reset to baseline. The resultant model takes the form of a functional-differential equation with continuous and impulsive components. Despite the impulsive nature of the inputs, realistic hormone profiles are generated, including ultradian and circadian rhythms, pulsatile secretory patterns, and even chaotic dynamics.
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Affiliation(s)
- Alexander N Churilov
- Faculty of Mathematics and Mechanics, St. Petersburg State University, Universitetsky av. 28, Stary Peterhof, 198504 St. Petersburg, Russia
| | - John Milton
- Keck Science Department, The Claremont Colleges, 925 North Mills Ave., Claremont, California 91711, USA
| | - Elvira R Salakhova
- Faculty of Mathematics and Mechanics, St. Petersburg State University, Universitetsky av. 28, Stary Peterhof, 198504 St. Petersburg, Russia
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7
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Lightman SL, Birnie MT, Conway-Campbell BL. Dynamics of ACTH and Cortisol Secretion and Implications for Disease. Endocr Rev 2020; 41:bnaa002. [PMID: 32060528 PMCID: PMC7240781 DOI: 10.1210/endrev/bnaa002] [Citation(s) in RCA: 138] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 02/13/2020] [Indexed: 12/20/2022]
Abstract
The past decade has seen several critical advances in our understanding of hypothalamic-pituitary-adrenal (HPA) axis regulation. Homeostatic physiological circuits need to integrate multiple internal and external stimuli and provide a dynamic output appropriate for the response parameters of their target tissues. The HPA axis is an example of such a homeostatic system. Recent studies have shown that circadian rhythmicity of the major output of this system-the adrenal glucocorticoid hormones corticosterone in rodent and predominately cortisol in man-comprises varying amplitude pulses that exist due to a subhypothalamic pulse generator. Oscillating endogenous glucocorticoid signals interact with regulatory systems within individual parts of the axis including the adrenal gland itself, where a regulatory network can further modify the pulsatile release of hormone. The HPA axis output is in the form of a dynamic oscillating glucocorticoid signal that needs to be decoded at the cellular level. If the pulsatile signal is abolished by the administration of a long-acting synthetic glucocorticoid, the resulting disruption in physiological regulation has the potential to negatively impact many glucocorticoid-dependent bodily systems. Even subtle alterations to the dynamics of the system, during chronic stress or certain disease states, can potentially result in changes in functional output of multiple cells and tissues throughout the body, altering metabolic processes, behavior, affective state, and cognitive function in susceptible individuals. The recent development of a novel chronotherapy, which can deliver both circadian and ultradian patterns, provides great promise for patients on glucocorticoid treatment.
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Affiliation(s)
- Stafford L Lightman
- Translational Health Science, Bristol Medical School, University of Bristol, Bristol, UK
| | - Matthew T Birnie
- Translational Health Science, Bristol Medical School, University of Bristol, Bristol, UK
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8
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Gibbison B, Keenan DM, Roelfsema F, Evans J, Phillips K, Rogers CA, Angelini GD, Lightman SL. Dynamic Pituitary-Adrenal Interactions in the Critically Ill after Cardiac Surgery. J Clin Endocrinol Metab 2020; 105:dgz206. [PMID: 31738827 PMCID: PMC7089849 DOI: 10.1210/clinem/dgz206] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 11/15/2019] [Indexed: 11/19/2022]
Abstract
CONTEXT Patients with critical illness are thought to be at risk of adrenal insufficiency. There are no models of dynamic hypothalamic-pituitary-adrenal (HPA) axis function in this group of patients and thus current methods of diagnosis are based on aggregated, static models. OBJECTIVE To characterize the secretory dynamics of the HPA axis in the critically ill (CI) after cardiac surgery. DESIGN Mathematical modeling of cohorts. SETTING Cardiac critical care unit. PATIENTS 20 male patients CI at least 48 hours after cardiac surgery and 19 healthy (H) male volunteers. INTERVENTIONS None. MAIN OUTCOME MEASURES Measures of hormone secretory dynamics were generated from serum adrenocorticotrophic hormone (ACTH) sampled every hour and total cortisol every 10 min for 24 h. RESULTS All CI patients had pulsatile ACTH and cortisol profiles. CI patients had similar ACTH secretion (1036.4 [737.6] pg/mL/24 h) compared to the H volunteers (1502.3 [1152.2] pg/mL/24 h; P = .20), but increased cortisol secretion (CI: 14 447.0 [5709.3] vs H: 5915.5 [1686.7)] nmol/L/24 h; P < .0001). This increase in cortisol was due to nonpulsatile (CI: 9253.4 [3348.8] vs H: 960 [589.0] nmol/L/24 h, P < .0001), rather than pulsatile cortisol secretion (CI: 5193.1 [3018.5] vs H: 4955.1 [1753.6] nmol/L/24 h; P = .43). Seven (35%) of the 20 CI patients had cortisol pulse nadirs below the current international guideline threshold for critical illness-related corticosteroid insufficiency, but an overall secretion that would not be considered deficient. CONCLUSIONS This study supports the premise that current tests of HPA axis function are unhelpful in the diagnosis of adrenal insufficiency in the CI. The reduced ACTH and increase in nonpulsatile cortisol secretion imply that the secretion of cortisol is driven by factors outside the HPA axis in critical illness.
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Affiliation(s)
- Ben Gibbison
- Department of Anaesthesia, Bristol Medical School, University of Bristol, Bristol, UK
| | - Daniel M Keenan
- Department of Statistics, University of Virginia, Charlottesville, VA, US
| | - Ferdinand Roelfsema
- Department of Internal Medicine, Section Endocrinology, University of Leiden, Leiden, The Netherlands
| | - Jon Evans
- Clinical Trials and Evaluation Unit, Bristol Trials Centre, University of Bristol, Bristol, UK
| | - Kirsty Phillips
- Department of Pathology, University Hospitals Bristol NHS Foundation Trust, Bristol, UK
| | - Chris A Rogers
- Clinical Trials and Evaluation Unit, Bristol Trials Centre, University of Bristol, Bristol, UK
| | - Gianni D Angelini
- Department of Cardiac Surgery, Bristol Medical School, University of Bristol, Bristol, UK
| | - Stafford L Lightman
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Bristol, UK
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Han SY, Cheong I, McLennan T, Herbison AE. Neural Determinants of Pulsatile Luteinizing Hormone Secretion in Male Mice. Endocrinology 2020; 161:5697320. [PMID: 31907531 DOI: 10.1210/endocr/bqz045] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 01/03/2020] [Indexed: 11/19/2022]
Abstract
The gonadotrophin-releasing hormone (GnRH) pulse generator drives pulsatile luteinizing hormone (LH) secretion essential for fertility. However, the constraints within which the pulse generator operates to drive efficient LH pulsatility remain unclear. We used optogenetic activation of the arcuate nucleus kisspeptin neurons, recently identified as the GnRH pulse generator, to assess the efficiency of different pulse generator frequencies in driving pulsatile LH secretion in intact freely behaving male mice. Activating the pulse generator at 45-minute intervals generated LH pulses similar to those observed in intact male mice while 9-minute interval stimulation generated LH profiles indistinguishable from gonadectomized (GDX) male mice. However, more frequent activation of the pulse generator resulted in disordered LH secretion. Optogenetic experiments directly activating the distal projections of the GnRH neuron gave the exact same results, indicating the pituitary to be the locus of the high frequency decoding. To evaluate the state-dependent behavior of the pulse generator, the effects of high-frequency activation of the arcuate kisspeptin neurons were compared in GDX and intact mice. The same stimulus resulted in an overall inhibition of LH release in GDX mice but stimulation in intact males. These studies demonstrate that the GnRH pulse generator is the primary determinant of LH pulse profile and that a nonlinear relationship exists between pulse generator frequency and LH pulse frequency. This may underlie the ability of stimulatory inputs to the pulse generator to have opposite effects on LH secretion in intact and GDX animals.
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Affiliation(s)
- Su Young Han
- Centre for Neuroendocrinology and Department of Physiology, University of Otago School of Biomedical Sciences, Dunedin, New Zealand
| | - Isaiah Cheong
- Centre for Neuroendocrinology and Department of Physiology, University of Otago School of Biomedical Sciences, Dunedin, New Zealand
| | - Tim McLennan
- Centre for Neuroendocrinology and Department of Physiology, University of Otago School of Biomedical Sciences, Dunedin, New Zealand
| | - Allan E Herbison
- Centre for Neuroendocrinology and Department of Physiology, University of Otago School of Biomedical Sciences, Dunedin, New Zealand
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10
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Taghvafard H, Cao M, Kawano Y, Faghih RT. Design of Intermittent Control for Cortisol Secretion Under Time-Varying Demand and Holding Cost Constraints. IEEE Trans Biomed Eng 2020; 67:556-564. [DOI: 10.1109/tbme.2019.2918432] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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11
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Vazquez-Jimenez A, Rodriguez-Gonzalez J. On Information Extraction and Decoding Mechanisms Improved by Noisy Amplification in Signaling Pathways. Sci Rep 2019; 9:14365. [PMID: 31591406 PMCID: PMC6779762 DOI: 10.1038/s41598-019-50631-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 09/12/2019] [Indexed: 02/04/2023] Open
Abstract
The cells need to process information about extracellular stimuli. They encode, transmit and decode the information to elicit an appropriate response. Studies aimed at understanding how such information is decoded in the signaling pathways to generate a specific cellular response have become essential. Eukaryotic cells decode information through two different mechanisms: the feed-forward loop and the promoter affinity. Here, we investigate how these two mechanisms improve information transmission. A detailed comparison is made between the stochastic model of the MAPK/ERK pathway and a stochastic minimal decoding model. The maximal amount of transmittable information was computed. The results suggest that the decoding mechanism of the MAPK/ERK pathway improve the channel capacity because it behaves as a noisy amplifier. We show a positive dependence between the noisy amplification and the amount of information extracted. Additionally, we show that the extrinsic noise can be tuned to improve information transmission. This investigation has revealed that the feed-forward loop and the promoter affinity motifs extract information thanks to processes of amplification and noise addition. Moreover, the channel capacity is enhanced when both decoding mechanisms are coupled. Altogether, these findings suggest novel characteristics in how decoding mechanisms improve information transmission.
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Affiliation(s)
- Aaron Vazquez-Jimenez
- Centro de Investigación y de Estudios Avanzados del IPN, Unidad Monterrey, Vía del conocimiento 201, Parque de Investigación e Innovación Tecnológica, 66600, Apodaca, NL, Mexico.
| | - Jesus Rodriguez-Gonzalez
- Centro de Investigación y de Estudios Avanzados del IPN, Unidad Monterrey, Vía del conocimiento 201, Parque de Investigación e Innovación Tecnológica, 66600, Apodaca, NL, Mexico.
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12
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Del Giudice M. Invisible Designers: Brain Evolution Through the Lens of Parasite Manipulation. QUARTERLY REVIEW OF BIOLOGY 2019. [DOI: 10.1086/705038] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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13
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Taghvafard H, Medvedev A, Proskurnikov AV, Cao M. Impulsive model of endocrine regulation with a local continuous feedback. Math Biosci 2019; 310:128-135. [DOI: 10.1016/j.mbs.2019.02.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Revised: 12/30/2018] [Accepted: 02/14/2019] [Indexed: 11/27/2022]
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14
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Zavala E, Wedgwood KCA, Voliotis M, Tabak J, Spiga F, Lightman SL, Tsaneva-Atanasova K. Mathematical Modelling of Endocrine Systems. Trends Endocrinol Metab 2019; 30:244-257. [PMID: 30799185 PMCID: PMC6425086 DOI: 10.1016/j.tem.2019.01.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 01/23/2019] [Accepted: 01/25/2019] [Indexed: 12/12/2022]
Abstract
Hormone rhythms are ubiquitous and essential to sustain normal physiological functions. Combined mathematical modelling and experimental approaches have shown that these rhythms result from regulatory processes occurring at multiple levels of organisation and require continuous dynamic equilibration, particularly in response to stimuli. We review how such an interdisciplinary approach has been successfully applied to unravel complex regulatory mechanisms in the metabolic, stress, and reproductive axes. We discuss how this strategy is likely to be instrumental for making progress in emerging areas such as chronobiology and network physiology. Ultimately, we envisage that the insight provided by mathematical models could lead to novel experimental tools able to continuously adapt parameters to gradual physiological changes and the design of clinical interventions to restore normal endocrine function.
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Affiliation(s)
- Eder Zavala
- Living Systems Institute, University of Exeter, Exeter EX4 4QD, UK; EPSRC Centre for Predictive Modelling in Healthcare, University of Exeter, Exeter EX4 4QD, UK; Centre for Biomedical Modelling and Analysis, University of Exeter, Exeter EX4 4QD, UK; College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, UK.
| | - Kyle C A Wedgwood
- Living Systems Institute, University of Exeter, Exeter EX4 4QD, UK; EPSRC Centre for Predictive Modelling in Healthcare, University of Exeter, Exeter EX4 4QD, UK; Centre for Biomedical Modelling and Analysis, University of Exeter, Exeter EX4 4QD, UK; College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, UK
| | - Margaritis Voliotis
- Living Systems Institute, University of Exeter, Exeter EX4 4QD, UK; EPSRC Centre for Predictive Modelling in Healthcare, University of Exeter, Exeter EX4 4QD, UK; Centre for Biomedical Modelling and Analysis, University of Exeter, Exeter EX4 4QD, UK; College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, UK
| | - Joël Tabak
- Institute of Biomedical and Clinical Science, College of Medicine and Health, University of Exeter, Exeter EX4 4PS, UK
| | - Francesca Spiga
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Bristol BS1 3NY, UK
| | - Stafford L Lightman
- EPSRC Centre for Predictive Modelling in Healthcare, University of Exeter, Exeter EX4 4QD, UK; Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Bristol BS1 3NY, UK
| | - Krasimira Tsaneva-Atanasova
- Living Systems Institute, University of Exeter, Exeter EX4 4QD, UK; EPSRC Centre for Predictive Modelling in Healthcare, University of Exeter, Exeter EX4 4QD, UK; Centre for Biomedical Modelling and Analysis, University of Exeter, Exeter EX4 4QD, UK; College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, UK
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Stanojević A, Marković VM, Čupić Ž, Kolar-Anić L, Vukojević V. Advances in mathematical modelling of the hypothalamic–pituitary–adrenal (HPA) axis dynamics and the neuroendocrine response to stress. Curr Opin Chem Eng 2018. [DOI: 10.1016/j.coche.2018.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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16
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Čupić Ž, Stanojević A, Marković VM, Kolar-Anić L, Terenius L, Vukojević V. The HPA axis and ethanol: a synthesis of mathematical modelling and experimental observations. Addict Biol 2017; 22:1486-1500. [PMID: 27189379 DOI: 10.1111/adb.12409] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Revised: 03/24/2016] [Accepted: 04/11/2016] [Indexed: 12/21/2022]
Abstract
Stress and alcohol use are interrelated-stress contributes to the initiation and upholding of alcohol use and alcohol use alters the way we perceive and respond to stress. Intricate mechanisms through which ethanol alters the organism's response to stress remain elusive. We have developed a stoichiometric network model to succinctly describe neurochemical transformations underlying the stress response axis and use numerical simulations to model ethanol effects on complex daily changes of blood levels of cholesterol, 6 peptide and 8 steroid hormones. Modelling suggests that ethanol alters the dynamical regulation of hypothalamic-pituitary-adrenal (HPA) axis activity by affecting the amplitude of ultradian oscillations of HPA axis hormones, which defines the threshold with respect to which the response to stress is being set. These effects are complex-low/moderate acute ethanol challenge (<8 mM) may reduce, leave unaltered or increase the amplitude of ultradian cortisol (CORT) oscillations, giving rise to an intricate response at the organism level, offering also a potential explanation as to why apparently discordant results were observed in experimental studies. In contrast, high-dose acute ethanol challenge (>8 mM) increases instantaneous CORT levels and the amplitude of ultradian CORT oscillations in a dose-dependent manner, affecting the HPA axis activity also during the following day(s). Chronic exposure to ethanol qualitatively changes the HPA axis dynamics, whereas ethanol at intoxicating levels shuts down this dynamic regulation mechanism. Mathematical modelling gives a quantitative biology-based framework that can be used for predicting how the integral HPA axis response is perturbed by alcohol.
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Affiliation(s)
- Željko Čupić
- Institute of Chemistry, Technology and Metallurgy, Department of Catalysis and Chemical Engineering; University of Belgrade; Belgrade Serbia
| | - Ana Stanojević
- Faculty of Physical Chemistry; University of Belgrade; Belgrade Serbia
| | | | - Ljiljana Kolar-Anić
- Institute of Chemistry, Technology and Metallurgy, Department of Catalysis and Chemical Engineering; University of Belgrade; Belgrade Serbia
- Faculty of Physical Chemistry; University of Belgrade; Belgrade Serbia
| | - Lars Terenius
- Department of Clinical Neuroscience, Center for Molecular Medicine; Karolinska Institutet; Stockholm Sweden
| | - Vladana Vukojević
- Department of Clinical Neuroscience, Center for Molecular Medicine; Karolinska Institutet; Stockholm Sweden
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17
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Iijima N, Miyamoto S, Matsumoto K, Takumi K, Ueta Y, Ozawa H. Development of an imaging system for in vivo real-time monitoring of neuronal activity in deep brain of free-moving rats. Histochem Cell Biol 2017; 148:289-298. [PMID: 28550404 DOI: 10.1007/s00418-017-1576-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2017] [Indexed: 12/31/2022]
Abstract
We have newly developed a system that allows monitoring of the intensity of fluorescent signals from deep brains of rats transgenically modified to express enhanced green fluorescent protein (eGFP) via an optical fiber. One terminal of the optical fiber was connected to a blue semiconductor laser oscillator/green fluorescence detector. The other terminal was inserted into the vicinity of the eGFP-expressing neurons. Since the optical fiber was vulnerable to twisting stresses caused by animal movement, we also developed a cage in which the floor automatically turns, in response to the turning of the rat's head. This relieved the twisting stress on the optical fiber. The system then enabled real-time monitoring of fluorescence in awake and unrestrained rats over many hours. Using this system, we could continuously monitor eGFP-expression in arginine vasopressin-eGFP transgenic rats. Moreover, we observed an increase of eGFP-expression in the paraventricular nucleus under salt-loading conditions. We then performed in vivo imaging of eGFP-expressing GnRH neurons in the hypothalamus, via a bundle consisting of 3000 thin optical fibers. With the combination of the optical fiber bundle connection to the fluorescence microscope, and the special cage system, we were able to capture and retain images of eGFP-expressing neurons from free-moving rats. We believe that our newly developed method for monitoring and imaging eGFP-expression in deep brain neurons will be useful for analysis of neuronal functions in awake and unrestrained animals for long durations.
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Affiliation(s)
- Norio Iijima
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, 113-8602, Japan. .,Center for Medical Science, International University of Health and Welfare, 2600-1 Kitakanamaru, Ohtawara, 324-8501, Japan.
| | - Shinji Miyamoto
- Indeco Inc., 1-11-14 Kasuga, Bunkyo-ku, Tokyo, 112-0003, Japan.,Activelase, 3-5-22 Imai, Oume-si, Tokyo, Japan
| | - Keisuke Matsumoto
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, 113-8602, Japan
| | - Ken Takumi
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, 113-8602, Japan.,Department of Zoology, Okayama University of Science, 1-1 Ridai-cho, Okayama, 700-0005, Japan
| | - Yoichi Ueta
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, 807-8555, Japan
| | - Hitoshi Ozawa
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, 113-8602, Japan
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18
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Abulseoud OA, Ho MC, Choi DS, Stanojević A, Čupić Ž, Kolar-Anić L, Vukojević V. Corticosterone oscillations during mania induction in the lateral hypothalamic kindled rat-Experimental observations and mathematical modeling. PLoS One 2017; 12:e0177551. [PMID: 28542167 PMCID: PMC5436765 DOI: 10.1371/journal.pone.0177551] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 04/28/2017] [Indexed: 01/03/2023] Open
Abstract
Changes in the hypothalamic-pituitary-adrenal (HPA) axis activity constitute a key component of bipolar mania, but the extent and nature of these alterations are not fully understood. We use here the lateral hypothalamic-kindled (LHK) rat model to deliberately induce an acute manic-like episode and measure serum corticosterone concentrations to assess changes in HPA axis activity. A mathematical model is developed to succinctly describe the entwined biochemical transformations that underlay the HPA axis and emulate by numerical simulations the considerable increase in serum corticosterone concentration induced by LHK. Synergistic combination of the LHK rat model and dynamical systems theory allows us to quantitatively characterize changes in HPA axis activity under controlled induction of acute manic-like states and provides a framework to study in silico how the dynamic integration of neurochemical transformations underlying the HPA axis is disrupted in these states.
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Affiliation(s)
- Osama A. Abulseoud
- Department of Psychiatry and Psychology; Mayo Clinic, Rochester, Minnesota, United States of America
- Chemistry and Drug Metabolism, IRP, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland, United States of America
| | - Man Choi Ho
- Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Doo-Sup Choi
- Department of Psychiatry and Psychology; Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Ana Stanojević
- University of Belgrade, Faculty of Physical Chemistry, Studentski trg 12–16, Belgrade, Serbia
| | - Željko Čupić
- University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Department of Catalysis and Chemical Engineering, Njegoševa 12, Belgrade, Serbia
| | - Ljiljana Kolar-Anić
- University of Belgrade, Faculty of Physical Chemistry, Studentski trg 12–16, Belgrade, Serbia
- University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Department of Catalysis and Chemical Engineering, Njegoševa 12, Belgrade, Serbia
| | - Vladana Vukojević
- Karolinska Institute, Department of Clinical Neuroscience, Center for Molecular Medicine CMM L8:01, Stockholm, Sweden
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Čupić Ž, Marković VM, Maćešić S, Stanojević A, Damjanović S, Vukojević V, Kolar-Anić L. Dynamic transitions in a model of the hypothalamic-pituitary-adrenal axis. CHAOS (WOODBURY, N.Y.) 2016; 26:033111. [PMID: 27036189 DOI: 10.1063/1.4944040] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Dynamic properties of a nonlinear five-dimensional stoichiometric model of the hypothalamic-pituitary-adrenal (HPA) axis were systematically investigated. Conditions under which qualitative transitions between dynamic states occur are determined by independently varying the rate constants of all reactions that constitute the model. Bifurcation types were further characterized using continuation algorithms and scale factor methods. Regions of bistability and transitions through supercritical Andronov-Hopf and saddle loop bifurcations were identified. Dynamic state analysis predicts that the HPA axis operates under basal (healthy) physiological conditions close to an Andronov-Hopf bifurcation. Dynamic properties of the stress-control axis have not been characterized experimentally, but modelling suggests that the proximity to a supercritical Andronov-Hopf bifurcation can give the HPA axis both, flexibility to respond to external stimuli and adjust to new conditions and stability, i.e., the capacity to return to the original dynamic state afterwards, which is essential for maintaining homeostasis. The analysis presented here reflects the properties of a low-dimensional model that succinctly describes neurochemical transformations underlying the HPA axis. However, the model accounts correctly for a number of experimentally observed properties of the stress-response axis. We therefore regard that the presented analysis is meaningful, showing how in silico investigations can be used to guide the experimentalists in understanding how the HPA axis activity changes under chronic disease and/or specific pharmacological manipulations.
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Affiliation(s)
- Željko Čupić
- Department of Catalysis and Chemical Engineering, Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Njegoševa 12, 11000 Belgrade, Serbia
| | - Vladimir M Marković
- Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11158 Belgrade, Serbia
| | - Stevan Maćešić
- Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11158 Belgrade, Serbia
| | - Ana Stanojević
- Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11158 Belgrade, Serbia
| | - Svetozar Damjanović
- Institute of Endocrinology, Diabetes and Metabolic Diseases, School of Medicine, University of Belgrade, Dr Subotica 13, 11000 Belgrade, Serbia
| | - Vladana Vukojević
- Department of Clinical Neuroscience, Karolinska Institutet, CMM L8:01, 17176 Stockholm, Sweden
| | - Ljiljana Kolar-Anić
- Department of Catalysis and Chemical Engineering, Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Njegoševa 12, 11000 Belgrade, Serbia
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20
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Sumit M, Neubig RR, Takayama S, Linderman JJ. Band-pass processing in a GPCR signaling pathway selects for NFAT transcription factor activation. Integr Biol (Camb) 2015; 7:1378-86. [PMID: 26374065 PMCID: PMC4630096 DOI: 10.1039/c5ib00181a] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Many biological processes are rhythmic and proper timing is increasingly appreciated as being critical for development and maintenance of physiological functions. To understand how temporal modulation of an input signal influences downstream responses, we employ microfluidic pulsatile stimulation of a G-protein coupled receptor, the muscarinic M3 receptor, in single cells with simultaneous real-time imaging of both intracellular calcium and NFAT nuclear localization. Interestingly, we find that reduced stimulation with pulses of ligand can give more efficient transcription factor activation, if stimuli are timed appropriately. Our experiments and computational analyses show that M3 receptor-induced calcium oscillations form a low pass filter while calcium-induced NFAT translocation forms a high pass filter. The combination acts as a band-pass filter optimized for intermediate frequencies of stimulation. We demonstrate that receptor desensitization and NFAT translocation rates determine critical features of the band-pass filter and that the band-pass may be shifted for different receptors or NFAT dynamics. As an example, we show that the two NFAT isoforms (NFAT4 and NFAT1) have shifted band-pass windows for the same receptor. While we focus specifically on the M3 muscarinic receptor and NFAT translocation, band-pass processing is expected to be a general theme that applies to multiple signaling pathways.
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Affiliation(s)
- M Sumit
- Biointerface Institute, North Campus Research Complex, University of Michigan, 2800 Plymouth Road, Ann Arbor, MI 48109, USA. and Biophysics Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - R R Neubig
- Department of Pharmacology and Toxicology, Michigan State University, 1355 Bogue Street, East Lansing, MI 48824, USA
| | - S Takayama
- Biointerface Institute, North Campus Research Complex, University of Michigan, 2800 Plymouth Road, Ann Arbor, MI 48109, USA. and Michigan Centre for Integrative Research in Critical Care, North Campus Research Complex, University of Michigan, 2800 Plymouth Road, Ann Arbor, MI 48109, USA
| | - J J Linderman
- Department of Biomedical Engineering, University of Michigan, 1107 Carl A. Gerstacker Building, 2200, Bonisteel Blvd, Ann Arbor, MI 48109, USA. and Department of Chemical Engineering, University of Michigan, Building 26, 2800 Plymouth Road, Ann Arbor, MI 48109, USA
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21
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Faghih RT, Dahleh MA, Brown EN. An optimization formulation for characterization of pulsatile cortisol secretion. Front Neurosci 2015; 9:228. [PMID: 26321898 PMCID: PMC4531247 DOI: 10.3389/fnins.2015.00228] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Accepted: 05/11/2015] [Indexed: 11/13/2022] Open
Abstract
Cortisol is released to relay information to cells to regulate metabolism and reaction to stress and inflammation. In particular, cortisol is released in the form of pulsatile signals. This low-energy method of signaling seems to be more efficient than continuous signaling. We hypothesize that there is a controller in the anterior pituitary that leads to pulsatile release of cortisol, and propose a mathematical formulation for such controller, which leads to impulse control as opposed to continuous control. We postulate that this controller is minimizing the number of secretory events that result in cortisol secretion, which is a way of minimizing the energy required for cortisol secretion; this controller maintains the blood cortisol levels within a specific circadian range while complying with the first order dynamics underlying cortisol secretion. We use an ℓ0-norm cost function for this controller, and solve a reweighed ℓ1-norm minimization algorithm for obtaining the solution to this optimization problem. We use four examples to illustrate the performance of this approach: (i) a toy problem that achieves impulse control, (ii) two examples that achieve physiologically plausible pulsatile cortisol release, (iii) an example where the number of pulses is not within the physiologically plausible range for healthy subjects while the cortisol levels are within the desired range. This novel approach results in impulse control where the impulses and the obtained blood cortisol levels have a circadian rhythm and an ultradian rhythm that are in agreement with the known physiology of cortisol secretion. The proposed formulation is a first step in developing intermittent controllers for curing cortisol deficiency. This type of bio-inspired pulse controllers can be employed for designing non-continuous controllers in brain-machine interface design for neuroscience applications.
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Affiliation(s)
- Rose T Faghih
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology Cambridge, MA, USA ; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology Cambridge, MA, USA ; Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital Boston, MA, USA ; Laboratory for Information and Decision Systems, Massachusetts Institute of Technology Cambridge, MA, USA
| | - Munther A Dahleh
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology Cambridge, MA, USA ; Laboratory for Information and Decision Systems, Massachusetts Institute of Technology Cambridge, MA, USA ; Engineering Systems Division, Massachusetts Institute of Technology Cambridge, MA, USA ; Institute for Data, Systems, and Society, Massachusetts Institute of Technology Cambridge, MA, USA
| | - Emery N Brown
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology Cambridge, MA, USA ; Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital Boston, MA, USA ; Institute for Medical Engineering and Science, Massachusetts Institute of Technology Cambridge, MA, USA ; Department of Anesthesia, Harvard Medical School Boston, MA, USA
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22
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Liu Z, Guo W. Modeling diurnal hormone profiles by hierarchical state space models. Stat Med 2015; 34:3223-34. [PMID: 26152819 DOI: 10.1002/sim.6579] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 06/12/2015] [Accepted: 06/16/2015] [Indexed: 12/11/2022]
Abstract
Adrenocorticotropic hormone (ACTH) diurnal patterns contain both smooth circadian rhythms and pulsatile activities. How to evaluate and compare them between different groups is a challenging statistical task. In particular, we are interested in testing (1) whether the smooth ACTH circadian rhythms in chronic fatigue syndrome and fibromyalgia patients differ from those in healthy controls and (2) whether the patterns of pulsatile activities are different. In this paper, a hierarchical state space model is proposed to extract these signals from noisy observations. The smooth circadian rhythms shared by a group of subjects are modeled by periodic smoothing splines. The subject level pulsatile activities are modeled by autoregressive processes. A functional random effect is adopted at the pair level to account for the matched pair design. Parameters are estimated by maximizing the marginal likelihood. Signals are extracted as posterior means. Computationally efficient Kalman filter algorithms are adopted for implementation. Application of the proposed model reveals that the smooth circadian rhythms are similar in the two groups but the pulsatile activities in patients are weaker than those in the healthy controls.
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Affiliation(s)
- Ziyue Liu
- Department of Biostatistics, Indiana University, Schools of Public Health and Medicine, Indianapolis, IN, 46202, U.S.A
| | - Wensheng Guo
- Department of Biostatistics & Epidemiology, University of Pennsylvania, School of Medicine, Philadelphia, 19104, PA, U.S.A
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23
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Dogan R, Merıc A, Gedık O, Tugrul S, Eren SB, Ozturan O. Does systemic steroid deficiency affect inner ear functions? Am J Otolaryngol 2015; 36:568-74. [PMID: 25599654 DOI: 10.1016/j.amjoto.2014.12.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 12/04/2014] [Accepted: 12/21/2014] [Indexed: 12/11/2022]
Abstract
PURPOSE Today corticosteroids are employed for the treatment of various inner ear disorders. In this study we have investigated probable changes in hearing functions resulting from a deficiency of systemic steroid secretions. MATERIALS AND METHODS Twenty four healthy female rats were used in our study, allocated into three groups (medical adrenalectomy, medical adrenalectomy+dexamethasone, no treatment). Audiological evaluations were conducted at the beginning of the study and on days 7, 14 and 21. Blood samples were taken at the beginning and at the end of the study and blood corticosterone levels were determined. RESULTS While there were no significant differences between the basal, 7th, 14th and 21st day DPOAE values of group 1, their ABR threshold values showed significant increases. In group 2, there were no significant differences between the basal, 7th, 14th and 21st day DPOAE values. ABR thresholds of group 2 showed significant increases on days 7 and 14 as compared to their basal values, but there were no significant differences between the 21st day and basal ABR threshold values. There were no significant differences between the basal cortisol levels of the three groups. The mean cortisol level of group 1 on day 21 was found to be significantly lower than those of groups 2 and 3. CONCLUSION The results of the study demonstrated that there were no significant changes in DPOAE values with the cessation of cortisol secretion, while there was a progressive increase in ABR thresholds, which could be overcome with cortisone replacement.
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Affiliation(s)
- Remzi Dogan
- Department of Otorhinolaryngology, Bayrampasa State Hospital, Bayrampasa, Istanbul, Turkey.
| | - Ayşenur Merıc
- Department of Otorhinolaryngology, Bezmialem Vakif University, Fatih, Istanbul, Turkey
| | - Ozge Gedık
- Faculty of Health Sciences, Department of Audiology, Bezmialem Vakif University, Fatih, Istanbul, Turkey
| | - Selahattin Tugrul
- Department of Otorhinolaryngology, Bezmialem Vakif University, Fatih, Istanbul, Turkey
| | - Sabri Baki Eren
- Department of Otorhinolaryngology, Bezmialem Vakif University, Fatih, Istanbul, Turkey
| | - Orhan Ozturan
- Department of Otorhinolaryngology, Bezmialem Vakif University, Fatih, Istanbul, Turkey
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Lanté F, Chafai M, Raymond EF, Salgueiro Pereira AR, Mouska X, Kootar S, Barik J, Bethus I, Marie H. Subchronic glucocorticoid receptor inhibition rescues early episodic memory and synaptic plasticity deficits in a mouse model of Alzheimer's disease. Neuropsychopharmacology 2015; 40:1772-81. [PMID: 25622751 PMCID: PMC4915261 DOI: 10.1038/npp.2015.25] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 01/13/2015] [Accepted: 01/15/2015] [Indexed: 01/08/2023]
Abstract
The early phase of Alzheimer's disease (AD) is characterized by hippocampus-dependent memory deficits and impaired synaptic plasticity. Increasing evidence suggests that stress and dysregulation of the hypothalamo-pituitary-adrenal (HPA) axis, marked by the elevated circulating glucocorticoids, are risk factors for AD onset. How these changes contribute to early hippocampal dysfunction remains unclear. Using an elaborated version of the object recognition task, we carefully monitored alterations in key components of episodic memory, the first type of memory altered in AD patients, in early symptomatic Tg2576 AD mice. We also combined biochemical and ex vivo electrophysiological analyses to reveal novel cellular and molecular dysregulations underpinning the onset of the pathology. We show that HPA axis, circadian rhythm, and feedback mechanisms, as well as episodic memory, are compromised in this early symptomatic phase, reminiscent of human AD pathology. The cognitive decline could be rescued by subchronic in vivo treatment with RU486, a glucocorticoid receptor antagonist. These observed phenotypes were paralleled by a specific enhancement of N-Methyl-D-aspartic acid receptor (NMDAR)-dependent LTD in CA1 pyramidal neurons, whereas LTP and metabotropic glutamate receptor-dependent LTD remain unchanged. NMDAR transmission was also enhanced. Finally, we show that, as for the behavioral deficit, RU486 treatment rescues this abnormal synaptic phenotype. These preclinical results define glucocorticoid signaling as a contributing factor to both episodic memory loss and early synaptic failure in this AD mouse model, and suggest that glucocorticoid receptor targeting strategies could be beneficial to delay AD onset.
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Affiliation(s)
- Fabien Lanté
- Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), Centre National de la Recherche Scientifique (CNRS), Université de Nice Sophia Antipolis, UMR 7275, Valbonne, France
| | - Magda Chafai
- Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), Centre National de la Recherche Scientifique (CNRS), Université de Nice Sophia Antipolis, UMR 7275, Valbonne, France
| | - Elisabeth Fabienne Raymond
- Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), Centre National de la Recherche Scientifique (CNRS), Université de Nice Sophia Antipolis, UMR 7275, Valbonne, France
| | - Ana Rita Salgueiro Pereira
- Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), Centre National de la Recherche Scientifique (CNRS), Université de Nice Sophia Antipolis, UMR 7275, Valbonne, France
| | - Xavier Mouska
- Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), Centre National de la Recherche Scientifique (CNRS), Université de Nice Sophia Antipolis, UMR 7275, Valbonne, France
| | - Scherazad Kootar
- Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), Centre National de la Recherche Scientifique (CNRS), Université de Nice Sophia Antipolis, UMR 7275, Valbonne, France
| | - Jacques Barik
- Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), Centre National de la Recherche Scientifique (CNRS), Université de Nice Sophia Antipolis, UMR 7275, Valbonne, France
| | - Ingrid Bethus
- Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), Centre National de la Recherche Scientifique (CNRS), Université de Nice Sophia Antipolis, UMR 7275, Valbonne, France
| | - Hélène Marie
- Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), Centre National de la Recherche Scientifique (CNRS), Université de Nice Sophia Antipolis, UMR 7275, Valbonne, France,Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), Centre National de la Recherche Scientifique (CNRS), Université de Nice Sophia Antipolis, UMR 7275, 660 Route des Lucioles, 06560 Valbonne, France, Tel: +33 4 93 95 34 40, Fax: +33 4 93 95 34 08, E-mail:
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25
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Bodei C, Bortolussi L, Chiarugi D, Guerriero ML, Policriti A, Romanel A. On the impact of discreteness and abstractions on modelling noise in gene regulatory networks. Comput Biol Chem 2015; 56:98-108. [PMID: 25909953 DOI: 10.1016/j.compbiolchem.2015.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 02/26/2015] [Accepted: 04/07/2015] [Indexed: 10/23/2022]
Abstract
In this paper, we explore the impact of different forms of model abstraction and the role of discreteness on the dynamical behaviour of a simple model of gene regulation where a transcriptional repressor negatively regulates its own expression. We first investigate the relation between a minimal set of parameters and the system dynamics in a purely discrete stochastic framework, with the twofold purpose of providing an intuitive explanation of the different behavioural patterns exhibited and of identifying the main sources of noise. Then, we explore the effect of combining hybrid approaches and quasi-steady state approximations on model behaviour (and simulation time), to understand to what extent dynamics and quantitative features such as noise intensity can be preserved.
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Affiliation(s)
| | - Luca Bortolussi
- Dip. di Matematica e Geoscienze, Università di Trieste, Italy; CNR-ISTI, Pisa, Italy; Modelling and Simulation Group, University of Saarland, Campus E 1 3, Saarbruecken, Germany.
| | - Davide Chiarugi
- CNR-ISTI, Pisa, Italy; Max Planck Institut of Colloids and Interfaces, Potsdam, Germany.
| | | | - Alberto Policriti
- Dip. di Matematica e Informatica, Università di Udine, Udine, Italy.
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Mattsson P, Medvedev A. Modeling of Testosterone Regulation by Pulse-Modulated Feedback. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 823:23-40. [DOI: 10.1007/978-3-319-10984-8_2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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27
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Nicolaides NC, Charmandari E, Chrousos GP, Kino T. Recent advances in the molecular mechanisms determining tissue sensitivity to glucocorticoids: novel mutations, circadian rhythm and ligand-induced repression of the human glucocorticoid receptor. BMC Endocr Disord 2014; 14:71. [PMID: 25155432 PMCID: PMC4155765 DOI: 10.1186/1472-6823-14-71] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 07/31/2014] [Indexed: 12/11/2022] Open
Abstract
Glucocorticoids are pleiotropic hormones, which are involved in almost every cellular, molecular and physiologic network of the organism, and regulate a broad spectrum of physiologic functions essential for life. The cellular response to glucocorticoids displays profound variability both in magnitude and in specificity of action. Tissue sensitivity to glucocorticoids differs among individuals, within tissues of the same individual and within the same cell. The actions of glucocorticoids are mediated by the glucocorticoid receptor, a ubiquitously expressed intracellular, ligand-dependent transcription factor. Multiple mechanisms, such as pre-receptor ligand metabolism, receptor isoform expression, and receptor-, tissue-, and cell type-specific factors, exist to generate diversity as well as specificity in the response to glucocorticoids. Alterations in the molecular mechanisms of glucocorticoid receptor action impair glucocorticoid signal transduction and alter tissue sensitivity to glucocorticoids. This review summarizes the recent advances in our understanding of the molecular mechanisms determining tissue sensitivity to glucocorticoids with particular emphasis on novel mutations and new information on the circadian rhythm and ligand-induced repression of the glucocorticoid receptor.
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Affiliation(s)
- Nicolas C Nicolaides
- Division of Endocrinology, Metabolism and Diabetes, First Department of Pediatrics, University of Athens Medical School, ‘Aghia Sophia’ Children’s Hospital, Athens 11527, Greece
- Division of Endocrinology and Metabolism, Clinical Research Center, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece
| | - Evangelia Charmandari
- Division of Endocrinology, Metabolism and Diabetes, First Department of Pediatrics, University of Athens Medical School, ‘Aghia Sophia’ Children’s Hospital, Athens 11527, Greece
- Division of Endocrinology and Metabolism, Clinical Research Center, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece
| | - George P Chrousos
- Division of Endocrinology, Metabolism and Diabetes, First Department of Pediatrics, University of Athens Medical School, ‘Aghia Sophia’ Children’s Hospital, Athens 11527, Greece
- Division of Endocrinology and Metabolism, Clinical Research Center, Biomedical Research Foundation of the Academy of Athens, Athens 11527, Greece
- Saudi Diabetes Study Research Group, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Tomoshige Kino
- Unit on Molecular Hormone Action, Program in Reproductive and Adult Endocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 2089, USA
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A mathematical model of pulse-coded hormone signal responses in pituitary gonadotroph cells. Math Biosci 2013; 246:38-46. [PMID: 24095971 DOI: 10.1016/j.mbs.2013.09.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 09/09/2013] [Accepted: 09/20/2013] [Indexed: 11/23/2022]
Abstract
Cells in the pituitary that synthesize luteinizing and follicle-stimulating hormones regulate the relative production of these two key reproductive hormones in response to signals from the hypothalamus. These signals are encoded in the frequency of gonadotrophin-releasing-hormone pulses. In vitro experiments with a murine-derived cell line have identified key elements of the processes that decode the signal to regulate transcription of the subunits encoding these hormones. The mathematical model described in this paper is based on the results of those experiments and advances quantitative understanding of the biochemical decoder. The model consists of non-linear differential equations for each of six processes that lead to the synthesis of follicle-stimulating hormone. Simulations of the model exhibit key characteristics found in the experiments, including a preference for follicle-stimulating hormone synthesis at low pulse frequencies and a loss of this characteristic when a mutation is introduced.
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Maranghi F, Tassinari R, Mantovani A. Toxicological assessment of drugs that affect the endocrine system in puberty-related disorders. Expert Opin Drug Metab Toxicol 2013; 9:1309-16. [PMID: 23790205 DOI: 10.1517/17425255.2013.811488] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
INTRODUCTION Toxicologists must ensure that clinical risk-to-benefit analysis should be made both for genders and age groups, with any treatment. Puberty concerns physiological changes leading to organism's maturation. Pubertal growth disorders are increasing in last decades: besides causing physical and psychological distress, they may signal underlying endocrine-metabolic abnormalities with serious health consequences later on. Therapeutic approaches for some health conditions in childhood and adolescence are considered. AREAS COVERED The authors discuss how some diseases and treatments can impact pubertal growth. The authors look at particular immunological disorders such as asthma and how both the disease and treatment affects pubertal growth. They also discuss how the provision of available data can help to assess the dose-response of the drug, in these cases, and minimize the chance of side effects. The authors also discuss pediatric inflammatory bowel disease and how both the disease and treatment can mitigate the growth delay. Last, but not least, the authors discuss how the effects of the drugs used in the treatment of psychiatric disorders may accentuate endocrine issues in juvenile patients. Hyperprolactinemia induction by some antipsychotics is highlighted as an example. EXPERT OPINION Appropriate risk-benefit analysis of drugs prescribed during childhood and adolescence and intended to be used in the long term is required. Furthermore, future treatment strategies and safer compounds development should be supported by the knowledge of mechanisms underlying adverse side effects in pubertal growth and development.
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Affiliation(s)
- Francesca Maranghi
- Food and Veterinary Toxicology Unit, Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità , Viale Regina Elena, 299, 00161 Rome , Italy +39 06 49902527 ; +39 06 4990 2363 ;
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Trune DR, Canlon B. Corticosteroid therapy for hearing and balance disorders. Anat Rec (Hoboken) 2012; 295:1928-43. [PMID: 23044978 PMCID: PMC3999710 DOI: 10.1002/ar.22576] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 07/24/2012] [Indexed: 12/20/2022]
Abstract
This review addresses the current status of steroid therapies for hearing and vestibular disorders and how certain misconceptions may be undermining the efficacy in restoring normal ear function, both experimentally and clinically. Specific misconceptions addressed are that steroid therapy is not effective, steroid-responsive hearing loss proves an underlying inflammatory problem in the ear, and steroids only have application to the hearing disorders listed below. Glucocorticoid therapy for hearing and balance disorders has been employed for over 60 years. It is recommended in cases of sudden hearing loss, Meniére's disease, immune-mediated hearing loss, and any vestibular dysfunction suspected of having an inflammatory etiology. The predominant steroids employed today are dexamethasone, prednisone, prednisolone, and methylprednisolone. Despite years of use, little is known of the steroid responsive mechanisms in the ear that are influenced by glucocorticoid therapy. Furthermore, meta-analyses and clinical study reviews occasionally question whether steroids offer any benefit at all. Foremost in the minds of clinicians is the immune suppression and anti-inflammatory functions of steroids because of their efficacy for autoimmune hearing loss. However, glucocorticoids have a strong binding affinity for the mineralocorticoid (aldosterone) and glucocorticoid receptors, both of which are prominent in the ear. Because the auditory and vestibular end organs require tightly regulated endolymph and perilymph fluids, this ion homeostasis role of the mineralocorticoid receptor cannot be overlooked in both normal and pathologic functions of the ear. The function of the glucocorticoid receptor is to provide anti-inflammatory and antiapoptotic signals by mediating survival factors.
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Affiliation(s)
- Dennis R Trune
- Oregon Hearing Research Center, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science University, Portland, Oregon 97239-3098, USA.
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Gonik M, Frank E, Keßler MS, Czamara D, Bunck M, Yen YC, Pütz B, Holsboer F, Bettecken T, Landgraf R, Müller-Myhsok B, Touma C, Czibere L. The endocrine stress response is linked to one specific locus on chromosome 3 in a mouse model based on extremes in trait anxiety. BMC Genomics 2012; 13:579. [PMID: 23114097 PMCID: PMC3557225 DOI: 10.1186/1471-2164-13-579] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 10/29/2012] [Indexed: 12/17/2022] Open
Abstract
Background The hypothalamic-pituitary-adrenal (HPA) axis is essential to control physiological stress responses in mammals. Its dysfunction is related to several mental disorders, including anxiety and depression. The aim of this study was to identify genetic loci underlying the endocrine regulation of the HPA axis. Method High (HAB) and low (LAB) anxiety-related behaviour mice were established by selective inbreeding of outbred CD-1 mice to model extremes in trait anxiety. Additionally, HAB vs. LAB mice exhibit comorbid characteristics including a differential corticosterone response upon stress exposure. We crossbred HAB and LAB lines to create F1 and F2 offspring. To identify the contribution of the endocrine phenotypes to the total phenotypic variance, we examined multiple behavioural paradigms together with corticosterone secretion-based phenotypes in F2 mice by principal component analysis. Further, to pinpoint the genomic loci of the quantitative trait of the HPA axis stress response, we conducted genome-wide multipoint oligogenic linkage analyses based on Bayesian Markov chain Monte Carlo approach as well as parametric linkage in three-generation pedigrees, followed by a two-dimensional scan for epistasis and association analysis in freely segregating F2 mice using 267 single-nucleotide polymorphisms (SNPs), which were identified to consistently differ between HAB and LAB mice as genetic markers. Results HPA axis reactivity measurements and behavioural phenotypes were represented by independent principal components and demonstrated no correlation. Based on this finding, we identified one single quantitative trait locus (QTL) on chromosome 3 showing a very strong evidence for linkage (2ln (L-score) > 10, LOD > 23) and significant association (lowest Bonferroni adjusted p < 10-28) to the neuroendocrine stress response. The location of the linkage peak was estimated at 42.3 cM (95% confidence interval: 41.3 - 43.3 cM) and was shown to be in epistasis (p-adjusted < 0.004) with the locus at 35.3 cM on the same chromosome. The QTL harbours genes involved in steroid synthesis and cardiovascular effects. Conclusion The very prominent effect on stress-induced corticosterone secretion of the genomic locus on chromosome 3 and its involvement in epistasis highlights the critical role of this specific locus in the regulation of the HPA axis.
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Affiliation(s)
- Mariya Gonik
- Max Planck Institute of Psychiatry, Munich, Germany
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Veldhuis JD, Liu PY, Takahashi PY, Weist SM, Wigham JR. Analysis of the impact of intravenous LH pulses versus continuous LH infusion on testosterone secretion during GnRH-receptor blockade. Am J Physiol Regul Integr Comp Physiol 2012; 303:R994-R1002. [PMID: 22992702 DOI: 10.1152/ajpregu.00314.2012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Gonadotrophin-releasing hormone (GnRH) pulsatility is required for optimal luteinizing hormone (LH) secretion, but whether LH pulsatility is required for physiological testosterone (T) secretion is not known. To test the postulate that pulses of recombinant human (rh) LH stimulate greater T secretion than continuous infusion of the same dose, a potent selective GnRH antagonist was administered overnight to 19 healthy men ages 18-49 yr. Subjects then received saline or rhLH intravenously continuously or as 6-min pulses intravenously every 1 or 2 h at the same total dose. Blood was sampled every 10 min for 10 h to quantify T responses. For the four interventions, the descending rank order of mean LH and mean T concentrations was 1-h = 2-h rhLH pulses > continuous rhLH > saline (P < 10(-3)). Plateau LH and T concentrations correlated positively (R(2) = 0.943, P = 0.029) as did LH concentrations and LH half-lives (R(2) = 0.962, P = 0.019). Percentage pulsatile T secretion assessed by deconvolution analysis (Keenan DM, Takahashi PY, Liu PY, Roebuck PD, Nehra AX, Iranmanesh A, Veldhuis JD. Endocrinology 147: 2817-2828, 2006) was the highest (P = 0.019), and half-time to attain peak T concentrations was the shortest (P < 10(-6)), for 1-h rhLH pulses. Approximate entropy (a pattern-regularity measure) revealed more orderly T secretion for 1- than 2-h rhLH pulses (P = 0.0076). Accordingly, a pulsatile LH signal, while not obligatory to maintain mean T concentrations, controls the mean plasma LH concentration and determines quantifiable patterns of T secretion. These data introduce the question whether blood T patterns in turn supervise distinctive target-tissue responses.
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Affiliation(s)
- Johannes D Veldhuis
- Endocrine Research Unit, Dept. of Internal Medicine, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, Rochester, MN 55905, USA.
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Mormede P, Terenina E. Molecular genetics of the adrenocortical axis and breeding for robustness. Domest Anim Endocrinol 2012; 43:116-31. [PMID: 22672758 DOI: 10.1016/j.domaniend.2012.05.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 04/20/2012] [Accepted: 05/14/2012] [Indexed: 11/25/2022]
Abstract
The concept of robustness refers to the combination of a high production potential and a low sensitivity to environmental perturbations. The importance of robustness-related traits in breeding objectives is progressively increasing toward the production of animals with a high production level in a wide range of climatic conditions and production systems, together with a high level of animal welfare. Current strategies to increase robustness include selection for "functional traits," such as skeletal and cardiovascular integrity, disease resistance, and mortality at various stages. It is also possible to use global evaluation of sensitivity to the environment (eg reaction norm analysis or canalization), but these techniques are difficult to implement in practice. The glucocorticoid hormones released by the adrenal cortex exert a wide range of effects on metabolism, the cardiovascular system, inflammatory processes, and brain function, for example. Protein catabolism toward energy production and storage (lipids and glycogen) supports their pivotal role in stress responses aiming at the adaptation and survival of individuals under strong environmental pressure. Large individual variations have been described in adrenocortical axis activity, with important physiopathological consequences. In terms of animal production, higher cortisol levels have negative effects on growth rate and feed efficiency and increase the fat:lean ratio of carcasses. On the contrary, cortisol has positive effects on functional traits and adaptation. Intense selection for lean tissue growth and more generally high protein output during the past decades has concomitantly reduced cortisol production, which may be responsible for the negative effects of selection on functional traits. In this paper, we review experimental evidence suggesting that the balance between production and functional traits was modified in favor of improved robustness by selecting animals with higher adrenocortical axis activity, as well as the molecular genetic tools that can be used to fine-tune this objective.
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Affiliation(s)
- P Mormede
- INRA, UMR 444 Génétique Cellulaire, F-31326 Castanet-Tolosan, France.
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Le Tissier PR, Hodson DJ, Lafont C, Fontanaud P, Schaeffer M, Mollard P. Anterior pituitary cell networks. Front Neuroendocrinol 2012; 33:252-66. [PMID: 22981652 DOI: 10.1016/j.yfrne.2012.08.002] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 08/17/2012] [Accepted: 08/18/2012] [Indexed: 12/17/2022]
Abstract
Both endocrine and non-endocrine cells of the pituitary gland are organized into structural and functional networks which are formed during embryonic development but which may be modified throughout life. Structural mapping of the various endocrine cell types has highlighted the existence of distinct network motifs and relationships with the vasculature which may relate to temporal differences in their output. Functional characterization of the network activity of growth hormone and prolactin cells has revealed a role for cell organization in gene regulation, the plasticity of pituitary hormone output and remarkably the ability to memorize altered demand. As such, the description of these endocrine cell networks alters the concept of the pituitary from a gland which simply responds to external regulation to that of an oscillator which may memorize information and constantly adapt its coordinated networks' responses to the flow of hypothalamic inputs.
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Affiliation(s)
- P R Le Tissier
- Division of Molecular Neuroendocrinology, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, United Kingdom;
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Featherstone K, White MRH, Davis JRE. The prolactin gene: a paradigm of tissue-specific gene regulation with complex temporal transcription dynamics. J Neuroendocrinol 2012; 24:977-90. [PMID: 22420298 PMCID: PMC3505372 DOI: 10.1111/j.1365-2826.2012.02310.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Transcription of numerous mammalian genes is highly pulsatile, with bursts of expression occurring with variable duration and frequency. The presence of this stochastic or 'noisy' expression pattern has been relatively unexplored in tissue systems. The prolactin gene provides a model of tissue-specific gene regulation resulting in pulsatile transcription dynamics in both cell lines and endocrine tissues. In most cell culture models, prolactin transcription appears to be highly variable between cells, with differences in transcription pulse duration and frequency. This apparently stochastic transcription is constrained by a transcriptional refractory period, which may be related to cycles of chromatin remodelling. We propose that prolactin transcription dynamics result from the summation of oscillatory cellular inputs and by regulation through chromatin remodelling cycles. Observations of transcription dynamics in cells within pituitary tissue show reduced transcriptional heterogeneity and can be grouped into a small number of distinct patterns. Thus, it appears that the tissue environment is able to reduce transcriptional noise to enable coordinated tissue responses to environmental change. We review the current knowledge on the complex tissue-specific regulation of the prolactin gene in pituitary and extra-pituitary sites, highlighting differences between humans and rodent experimental animal models. Within this context, we describe the transcription dynamics of prolactin gene expression and how this may relate to specific processes occurring within the cell.
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Affiliation(s)
- K Featherstone
- Developmental Biomedicine Research Group, Faculty of Medical and Human Sciences, University of Manchester, Manchester, UK.
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Rankin J, Walker JJ, Windle R, Lightman SL, Terry JR. Characterizing dynamic interactions between ultradian glucocorticoid rhythmicity and acute stress using the phase response curve. PLoS One 2012; 7:e30978. [PMID: 22363526 PMCID: PMC3283588 DOI: 10.1371/journal.pone.0030978] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 12/30/2011] [Indexed: 11/29/2022] Open
Abstract
The hypothalamic-pituitary-adrenal (HPA) axis is a dynamic oscillatory hormone signalling system that regulates the pulsatile secretion of glucocorticoids from the adrenal glands. In addition to regulation of basal levels of glucocorticoids, the HPA axis provides a rapid hormonal response to stress that is vitally important for homeostasis. Recently it has become clear that glucocorticoid pulses encode an important biological signal that regulates receptor signalling both in the central nervous system and in peripheral tissues. It is therefore important to understand how stressful stimuli disrupt the pulsatile dynamics of this system. Using a computational model that incorporates the crucial feed-forward and feedback components of the axis, we provide novel insight into experimental observations that the size of the stress-induced hormonal response is critically dependent on the timing of the stress. Further, we employ the theory of Phase Response Curves to show that an acute stressor acts as a phase-resetting mechanism for the ultradian rhythm of glucocorticoid secretion. Using our model, we demonstrate that the magnitude of an acute stress is a critical factor in determining whether the system resets via a Type 1 or Type 0 mechanism. By fitting our model to our in vivo stress-response data, we show that the glucocorticoid response to an acute noise stress in rats is governed by a Type 0 phase-resetting curve. Our results provide additional evidence for the concept of a deterministic sub-hypothalamic oscillator regulating the ultradian glucocorticoid rhythm, which constitutes a highly responsive peripheral hormone system that interacts dynamically with hypothalamic inputs to regulate the overall hormonal response to stress.
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Affiliation(s)
- James Rankin
- Bristol Centre for Applied Nonlinear Mathematics, University of Bristol, Bristol, United Kingdom
- INRIA Sophia-Antipolis, Sophia Antipolis, France
| | - Jamie J. Walker
- Bristol Centre for Applied Nonlinear Mathematics, University of Bristol, Bristol, United Kingdom
- Henry Wellcome Laboratories for Integrative Neuroscience & Endocrinology, University of Bristol, Bristol, United Kingdom
| | - Richard Windle
- School of Nursing, Midwifery and Physiotherapy, University of Nottingham, Nottingham, United Kingdom
| | - Stafford L. Lightman
- Henry Wellcome Laboratories for Integrative Neuroscience & Endocrinology, University of Bristol, Bristol, United Kingdom
| | - John R. Terry
- Henry Wellcome Laboratories for Integrative Neuroscience & Endocrinology, University of Bristol, Bristol, United Kingdom
- Department of Automatic Control and Systems Engineering, University of Sheffield, Sheffield, United Kingdom
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
- * E-mail:
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Meltser I, Canlon B. Protecting the auditory system with glucocorticoids. Hear Res 2011; 281:47-55. [PMID: 21718769 DOI: 10.1016/j.heares.2011.06.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 06/07/2011] [Accepted: 06/09/2011] [Indexed: 01/03/2023]
Abstract
Glucocorticoids are hormones released following stress-related events and function to maintain homeostasis. Glucocorticoid receptors localize, among others, to hair cells, spiral ligament and spiral ganglion neurons. Glucocorticoid receptor-induced protection against acoustic trauma is found by i) pretreatment with glucocorticoid agonists; ii) acute restraint stress; and iii) sound conditioning. In contrast, glucocorticoid receptor antagonists exacerbate hearing loss. These findings have important clinical significance since synthetic glucocorticoids are commonly used to treat hearing loss. However, this treatment has limited success since hearing improvement is often not maintained once the treatment has ended, a fact that reduces the overall appeal for this treatment. It must be realized that despite the widespread use of glucocorticoids to treat hearing disorders, the molecular mechanisms underlying this treatment are not well characterized. This review will give insight into some physiological and biochemical mechanisms underlying glucocorticoid treatment for preventing hearing loss.
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Affiliation(s)
- Inna Meltser
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
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