In our group we think combining knowledge across psychology and genetics may be important for future prevention and treatment of long lasting mental and physical afflictions. Hence, the purpose of the master project is to provide new knowledge about how exposure to social stress, through genetic mechanisms, may lead to long-term changes in the brain and persistent pain. The research questions are as follows:
In animals – screening for important genes and pathways;
- How does social stress influence global gene expression and DNA methylation in the pituitary gland of the brain?
- Which genes and signaling pathways are involved in such stress-induced changes in the pituitary gland of the brain?
In humans – following up the main findings of the screening;
- What are the relationship between social stress and subjective health complaints such as pain for example headache?
- How are these relationships moderated by the genetic variability in genes and signaling pathways up- or downregulated by social stress in the animal screening-experiments?
Methods
In the animal arm of the project, we use a so-called resident intruder paradigm, where an intruder rat (Sprague Dawley) has been exposed to social stress by a dominant resident rat (Long Evans) for one hour each day for seven consecutive days. The most relevant brain tissue, i.e. the pituitaries, has already been harvested and RNA and DNA isolated. Moreover, RNA sequencing and bisulfite DNA sequencing data have been provided by the commercial company Novogene, and the data are returned to our lab for further processing. Next step now is therefore to analyze the data with regard to gene expression (mRNA levels) and epigenetic changes (DNA methylation pattern) induced by social stress. This will be done in-house by the software Reactome and other software tools. Replication of the most important findings will be performed qPCR (StepOnePlus, Thermofisher) and by pyrosequencing (PyroMark Q48, Qiagene).
In the human arm of the project, genomic DNA that has previously been extracted from 1200 individuals (general working population) using OrageneRNA saliva sample collection kit (DNA Genotech Inc.), will be used. Single nucleotide polymorphism (SNP) genotyping will be carried out using predesigned TaqMan SNP genotyping assays (Applied Biosystems). All statistical analysis will be conducted using Stata SE 16.