Dr. Monika Ehrhart-Bornstein
Previous and current research
1. Intercellular Interactions in the Endocrine System
One focus of our research is defining basic mechanisms and clinical implications of cellular crosstalk in endocrine tissues. The adrenal gland comprises two endocrine tissues of distinct origin, the catecholamine-producing medulla and the steroid-producing cortex. Using the adrenal gland as a model we have demonstrated that tissue integrity, input from the nervous system or intercellular communication is essential for the normal functioning of the gland and the adequate respond to the homeostatic challenges of stress. We have demonstrated that intact intraglandular cellular interactions are required for normal development, differentiation and zonation of the adrenals and that alterations in intercellular communication, local production of neuropeptides, growth factors and cytokines, and aberrant expression of ectopic receptors are implicated in adrenal hyperplasia, autonomic hormone production and tumour formation.
In ongoing research, we are now focussing on the involvement of these intraglandular cellular interactions in the development of adrenomedullary neuroendocrine cells from neural crest-derived proliferation competent cells.
2. Endocrine Function of Adipose Tissue
In Westernized countries overweight and obesity have reached epidemic proportions with dramatic medical consequences. Obesity is a major risk factor for lipid abnormalities, atherosclerosis, type 2 diabetes mellitus, certain types of cancer, and high blood pressure. The adipocyte has long been suggested to be directly involved in the body’s homeostasis and recent evidence now proves that adipose tissue is a highly active endocrine organ. We therefore test the hypothesis that adipose secretory factors directly influence the body’s endocrine system and consequently are responsible for some of the medical problems associated with overweight. Indeed, factors (adipotensins) secreted from human adipocytes directly stimulate adrenal steroidogenesis, with the most prominent effect on aldosterone secretion. Adipocytes can influence adrenal function in an endocrine manner via secretion into the blood stream or in a paracrine manner due to the fact that adipocytes are regularly located within the adrenal gland. These data indicate that adipocytes directly stimulate adrenal aldosterone secretion, the body’s most potent mineralocorticoid and therefore might be responsible for obesity hypertension.
In ongoing studies we are now:
1. Characterizing the factors responsible for this stimulation.
2. Identifying the signalling pathways involved in the adipocyte mediated aldosterone secretion
Sicard F, Ehrhart-Bornstein M, Corbeil D, Sperber S, Krug AW, Ziegler CG, Rettori V, McCann SM, Bornstein SR 2007 Age-dependent regulation of chromaffin cell proliferation by growth factors, dehydroepiandrosterone (DHEA), and DHEA sulfate. Proc Natl Acad Sci U S A 104:2007-2012
- Krug AW, Vleugels K, Schinner S, Lamounier-Zepter V, Ziegler CG, Bornstein SR, Ehrhart-Bornstein M 2007 Human adipocytes induce an ERK1/2 MAPkinases - mediated upregulation of steroidogenic acute regulatory protein (StAR) and an angiotensin II - sensitization in human adrenocortical cells. Int J Obes Apr 24; [Epub ahead of print]
Lamounier-Zepter V Ehrhart-Bornstein M, Karczewski S, Bornstein SR, Morano I 2006. Human adipocytes attenuate cardiomyocytes contraction. Characterization of an adipocyte-derived negative inotropic activity. FASEB J 20:1653-1659
- Krug AW, Ehrhart-Bornstein M 2005 Newly discovered endocrine functions of white adipose tissue: possible relevance in obesity-related diseases. Cell Mol Life Sci 62; 1359-1362
- Seres J, Bornstein SR, Seres P, Willenberg HS, Schulte KM, Scherbaum WA, Ehrhart-Bornstein M 2004 Corticotropin-releasing hormone (CRH) system in human adipose tissue. J Clin Endocrinol Metab 89:965-970
- Ehrhart-Bornstein M, Lamounier-Zepter V, Schraven A, Langenbach J, Willenberg HS, Barthel A, Hauner H, McCann SM, Scherbaum WA, Bornstein SR 2003 Human adipocytes secrete mineralocorticoid releasing factors. Proc Natl Acad Sci U S A 100:14211-14216
- Alesci S, Ramsey WJ, Bornstein SR, Chrousos GP, Hornsby PJ, Benvenga S, Trimarchi F, Ehrhart-Bornstein M 2002 Adenoviral vectors can impair adrenocortical steroidogenesis: clinical implications for natural infections and gene therapy. Proc Natl Acad Sci U S A 99:7484-7489
- Haidan A, Bornstein SR, Liu Z, Walsh LP, Stocco DM, Ehrhart-Bornstein M 2000 Expression of adrenocortical steroidogenic acute regulatory (StAR) protein is influenced by chromaffin cells . Molec Cell Endocrinol 165:25-32
- Ehrhart-Bornstein M, Hinson JP, Bornstein SR, Scherbaum WA, Vinson GP 1998 Intraadrenal interactions in the regulation of adrenocortical steroidogenesis. Endocrine Reviews 19:101-14
1979-1985: University of Ulm, Biology Faculty, Diploma degree in Biology
1985-1988: University of Ulm, Department of Anatomy and Cellbiology Ph.D. Thesis
1989: Panum Institute, Department of Physiology, Copenhagen, Denmark Postdoctoral research
1990-1993: University of Ulm, Department of Internal Medicine I, Ulm, Germany Research associate,
1994-1997: University of Leipzig, Medical Clinic, Leipzig, Germany Reserach associate
1999-2001: NICHD, National Institutes of Health, Bethesda, USA
2001-2004: German Diabetes Center, Düsseldorf, Germany Group leader
since 2005: University of Dresden, Medical Clinic III Group leader