The Corticotropin Releasing Factor Network in the brain and the influences of estrogen; A microdialysis study | Application
The Corticotropin Releasing Factor Network in the brain and the influences of estrogen; A microdialysis study
Registration number: LIO-10544
Ansökan om enbart LFoU-medel (NYTT!)
Application started by: Susanne Hilke, 2007-05-24
Professional title at the time of application: MSc, PhD
Work place at the time of application: Klinisk kemi/Neurokemi
Last updated / corrected by: Agneta Linghag, 2009-02-12
Application received by: Region Östergötland
Granted and completedGranted and completed
Applicant: Susanne Hilke
Med Dr, Diagnostikcentrum

Projektinformation

Sammanfattning

This project is carried out in close collaboration with Professor Wylie Vale and Dr Mark Huising at the Salk Institute, La Jolla, San Diego, USA.

Summary
Corticotropin releasing factor (CRF) is a member of a family of neuropeptides and involved in diverse roles of homeostatic balance and important for the rapid mobilization of resources and behaviours in response to stress (Vale et al., 1981). Included in the CRF network is a soluble 37 kDa binding protein (CRF-BP) that binds CRF with high affinity, thus preventing receptor activation (Behan et al., 1995). This binding protein is suggested to be a unique player in the network of CRF-signaling.

The physiological significance of the above described soluble CRF-binding protein is still incompletely understood. However, Herringa et al (2004) demonstrated that acute restraint stress increases rat basolateral amygdala (BLA) CRF-BP gene expression up to 21 h after the stressor. Intriguingly, there is compelling evidence for gender differences in the regulation of CRF-BP and on influences of estrogen on the CRF-BP gene expression. Indeed, the CRF-BP gene is a target for estradiol-bound ERα (Stolpe et al., 2004). Moreover, pituitary CRF-BP mRNA levels vary across the estrous cycle, with greatest expression at proestrus, and ovariectomy has been shown to induce a decrease in CRF-BP mRNA whereas estrogen treatment restores CRF-BP mRNA in the pituitary, suggesting estrogen regulation of CRF-BP (Speert 2002).

Our specific goal with this project is to i) investigate the influence of estrogen on the release of CRF-BP in brain areas involved in anxiety e.g. the BSA, by means of in vivo microdialysis and ii) quantitatively measure mRNA of CRF-BP by means of q-PCR using the same estrogen treatment protocol.

Background
The CRF family and physiology
The CRF family includes CRF and the related ligands urocortin (Ucn) - 1,2 and 3. This family of neuropeptides acts via one of two CRF receptors to play a crucial role in the integration of the body’s overall response to stress by triggering the hypothalamic-pituitary-adrenal axis (HPA) (Vale et al., 1981). For example, the HPA axis is activated by the release of the CRF in hypothalamus into the pituitary capillary bed, leading to production and release of adrenocorticotropic hormone (ACTH) which induces the synthesis of glucocorticoids and their release from the adrenals into the general circulation. While activation of the HPA axis is essential for the ability to cope with stressors, extreme or prolonged activation underlies anxiety and depression (Owens and Nemeroff, 1993, Nemeroff and Vale, 2005). CRF and urocortins act through two CRF receptors, named CRFR1 and CRFR2. The human CRF1 receptor was cloned by Vale and co-workers in 1993 and is the principle receptor activating pituitary corticotropes during the stress response (Chen et al., 1993).
CRF-BP is widely expressed within the central nervous system, including the cerebral cortex, the amygdala, bed nucleus of the stria terminalis, olfactory bulb, and various nuclei within the brain stem and hypothalamus. Moreover, CRF-BP is expressed in anterior pituitary corticotropes and is capable of abrogating the CRF-induced release of ACTH from pituitary cells in vitro.

Estrogen
Estrogen binds to specific receptors within the cytoplasma or at the nucleus and associates with estrogen responsive elements. The estrogen receptor (ER) that was discovered first is called ERα. Gustafsson and co-workers (Kuiper et al., 1996; Mosselman et al., 1996) more recently discovered the second estrogen receptor (ERβ). Estrogen also activates a variety of alternative signalling pathways that bypass the cell nucleus, some of which are independent of the classical nuclear estrogen receptors ERα and ERβ (see Toran-Allerand, 2005). Estrogen has diverse effects on the brain beyond reproduction ( e.g. memory, mood) although the mechansim behind it is not completely understood.

Referenser

Bale, T. L. and Vale, W. W., 2003. Increased depression-like behaviors in corticotropin-releasing factor receptor-2-deficient mice: sexually dichotomous responses. J Neurosci. 23, 5295-5301.

Chen, R., Lewis, K. A., Perrin, M. H. and Vale, W. W., 1993. Expression cloning of a human corticotropin-releasing-factor receptor. Proc Natl Acad Sci U S A. 90, 8967-8971.
Chung, J. B., Silverman, M. and Monroe, J. G., 2003. Transitional B cells: step by step towards immune competence. Trends Immunol. 24, 343-349.

Gehlert, D. R., Shekhar, A., Morin, S. M., Hipskind, P. A., Zink, C., Gackenheimer, S. L., Shaw, J., Fitz, S. D. and Sajdyk, T. J., 2005. Stress and central Urocortin increase anxiety-like behavior in the social interaction test via the CRF1 receptor. Eur J Pharmacol. 509, 145-153.

Grace, C. R., Perrin, M. H., DiGruccio, M. R., Miller, C. L., Rivier, J. E., Vale, W. W.
& Riek, R. (2004) Proc. Natl. Acad. Sci. USA 101, 12836–12841.

Koob, G. F. and Heinrichs, S. C., 1999. A role for corticotropin releasing factor and urocortin in behavioral responses to stressors. Brain Res. 848, 141-152.

Nemeroff, C. B. and Vale, W. W., 2005. The neurobiology of depression: inroads to treatment and new drug discovery. J Clin Psychiatry. 66 Suppl 7, 5-13.

Nielsen, D. M., 2006. Corticotropin-releasing factor type-1 receptor antagonists: the next class of antidepressants? Life Sci. 78, 909-919.

Owens, M. J. and Nemeroff, C. B., 1993. The role of corticotropin-releasing factor in the pathophysiology of affective and anxiety disorders: laboratory and clinical studies. Ciba Found Symp. 172, 296-308; discussion 308-216.

Rivier, C., 1999. Gender, sex steroids, corticotropin-releasing factor, nitric oxide, and the HPA response to stress. Pharmacol Biochem Behav. 64, 739-751.

Vale, W., Spiess, J., Rivier, C. and Rivier, J., 1981. Characterization of a 41-residue ovine hypothalamic peptide that stimulates secretion of corticotropin and beta-endorphin. Science. 213, 1394-1397.

Veith, R. C., Lewis, N., Langohr, J. I., Murburg, M. M., Ashleigh, E. A., Castillo, S., Peskind, E. R., Pascualy, M., Bissette, G., Nemeroff, C. B. and et al., 1993. Effect of desipramine on cerebrospinal fluid concentrations of corticotropin-releasing factor in human subjects. Psychiatry Res. 46, 1-8.

Viau, V., Bingham, B., Davis, J., Lee, P. and Wong, M., 2005. Gender and puberty interact on the stress-induced activation of parvocellular neurosecretory neurons and corticotropin-releasing hormone messenger ribonucleic acid expression in the rat. Endocrinology. 146, 137-146.

Viau, V. and Meaney, M. J., 1991. Variations in the hypothalamic-pituitary-adrenal response to stress during the estrous cycle in the rat. Endocrinology. 129, 2503-2511.

Projektbudget

Summa projektbudget

200 000.00

Ange antal år projektbudgeten är baserad på

2 år

Äskade medel

DescriptionShort description of the costSum
Allmän forskningsersättningFörbrukningsvaror microdialys (prober, slangar)
Kirurgisk borr, nålförare, suturer
Djur
Anestesimedel
Smärtstillande medel
Ringer Acetat och andra kemikalier
200 000
Sum 200 000

Decision

Decision date: 2007-11-26

Brief description of each costApplied sumDecision SEKLFoU (kr)Decision comment
Allmän forskningsersättning
Förbrukningsvaror microdialys (prober, slangar)
Kirurgisk borr, nålförare, suturer
Djur
Anestesimedel
Smärtstillande medel
Ringer Acetat och andra kemikalier
200 000075 000LFoU 75 tkr
sum200 000075 000 

The Corticotropin Releasing Factor Network in the brain and the influences of estrogen; A microdialysis study | Application, from Region Östergötland
http://researchweb.org/is/en/lio/ansokan/10544