A smart look at how hormones affect our brain
Making smart use of an existing ‘brain atlas’ provides a treasure trove of information on how hormones affect our brain. So published researchers from Leiden University Medical Center (LUMC) and TU Delft on 26 January in PNAS. The researchers applied data mining to the Allen Brain Atlas, an enormous dataset which records the activity of 20,000 genes in the mouse brain.
Stress and sex hormones have a great deal of impact upon the brain, for example upon the memory and emotions. But it is still unclear which brain areas are affected by which hormones and exactly how this works. “Researchers tend to look at the same areas of the brain”, explains endocrinologist Dr Onno Meijer (LUMC). “But there are at least 900 areas that could be relevant.”
Link between oestrogens and cortisol
When a hormone receptor receives a signal from its 'own' hormone in the brain, the receptor travels – often in intermediate steps – to the cell nucleus which contains the DNA. Certain genes then become active, that is to say they start to produce proteins. Looking at which genes in the same area in the brain are active as the genes that are responsible for making the hormone receptors enables us to discover all kinds of relationships. For example, the researchers saw that oestrogen and cortisol are both able to control several areas in the brain at the same time, whereas dopamine-rich areas are very selectively sensitive to cortisol and testosterone. “These are very useful insights which can be largely transferred to the human brain. In the future we hope to also apply our method of data analysis to data from the human brain”, says Meijer.
Almost down to the micrometre
The researchers barely had to carry out any experiments themselves: they were able to make good use of the Allen Brain Atlas. This was created by a large brain institute in Seattle using hundreds of millions of dollars of financial support from Paul Allen (co-founder of Microsoft). The atlas contains detailed data of where 20,000 genes are active throughout the mouse brain. “In the atlas the brain is divided into 60,000 blocks measuring 200 by 200 micrometres”, explains Professor Marcel Reinders (TU Delft). The scientists brought order into this huge mountain of data and then started looking for relationships. “This atlas is a public resource. It offers researchers a fantastic opportunity to test their own hypotheses," says lead author Ahmed Mahfouz (LUMC).
The research was carried out as part of the STW Genes in Space project (12721: PI: Prof. Lelieveldt), in the LUMC Radiology and Endocrinology departments, the Erasmus MC Endocrinology department, and the Pattern Recognition and Bioinformatics group at TU Delft.
For more information please contact the Communications department at Leiden University Medical Center, tel. +31 (0)71 526 8005, firstname.lastname@example.org, www.lumc.nl/actueel or Claire Hallewas, TU Delft Science Information Officer, email@example.com tel. +31 (0)6 4095 3085.