Transposable elements and the evolution of the human brain
During the last 30-40 million years the primate brain has expanded in size, ultimately resulting in a new level of cognitive functions in humans. However, the genetic alterations driving this evolutionary process are poorly understood. In this project we investigate the role transposable elements have played in this process.
Transposable elements have entered our genome as mobile elements, causing major interspecies differences in the composition of the genome. As a consequence, a large portion of genetic information specific to primates and humans is stored in transposable elements. Therefore, transposons are a likely candidate to have mediated evolutionary processes, including those which resulted in the complexity of the human brain.
In this project we use induced pluripotent stem cell lines from various primate species to perform direct comparative analysis in stem cell derived cultures such as cerebral organoids. The project utilizes CRISPR-based gene editing which allows us to move genetic elements from one species to another. These studies will provide novel understanding on how transposons have contributed to what makes us human.
Lund university's press release: What makes us human? The answer may be found in overlooked DNA.
A role for transposons in neurodegenerative disorders
The underlying cause for most neurodegenerative disorders is poorly understood and current treatments are largely ineffective. New ideas and concepts are therefore vitally important for future research in this area. In this project we investigate the idea that dysregulation of transposable elements contributes to the onset and pathology of neurodegenerative disorders. Despite transposons making up at least half of the human genome, they are vastly understudied in relation to brain disorders.
We are using large-scale single-nuclei RNA-sequencing of postmortem tissue to investigate the pathological role of transposons in both acute neurodegeneration occurring after traumatic brain injury as well as in progressive neurodegeneration in Parkinson’s disease. We hypothesize that aberrant activation of transposons contributes to the neuroinflammation and neurotoxicity of these pathological states. This idea is based on experiments performed in mouse models in our lab (Jönsson et al., EMBO J 2021).
We also use human induced pluripotent stem cells to investigate how polymorphic transposable elements contribute a genetic component to these disorders, using X-linked dystonia Parkinsonism as our current focus.
An increased understanding of the relationship between transposons and pathological processes in the brain will result in novel diagnostic tools and therapeutic approaches for neurodegenerative disorders.
This project is supported by Aligning Science Across Parkinson’s (ASAP), The Collaborative Center for X-Linked Dystonia-Parkinsonism and Parkinsonfonden.
Lund university's press release: Activation of ancient viruses during brain development causes inflammation
Lund university's press release: Researchers to investigate the role of transposable elements in neuroinflammation and Parkinson’s disease
Transposons and glioma
Global changes in epigenetic marks is a hallmark of most brain tumors. However, the functional consequences
of these epigenetic changes remain unclear. In this project we investigate if epigenetic changes in glioma result in dysregulation of transposable elements. Transposable elements are largely overlooked in current cancer research, despite constituting more than 50% of the human genome. Therefore, their dysregulation is likely to have severe consequences.
In this project we use large-scale single-nuclei RNA-sequencing of glioma resections to investigate the expression of transposable elements in glioma. These experiments are closely linked to epigenetic analysis and gene editing experiments performed in cell culture models of glioma.
Using these techniques, we are exploring a novel route towards treatment of human glioma.
Transposable elements and human brain ageing
Aging is the single most important risk factor in the development of many diseases including chronic neurodegenerative disorders of the central nervous system. However, how exactly aging contributes to disease penetrance and pathology remains largely unknown, since it has been notoriously difficult to study the biology of human aging in the lab. What is clear is that ageing is a progressive process that is influenced by genetic and environmental factors. Recently, epigenetic mechanisms have been linked to aging and measurements of patterns of DNA-methylation can precisely determine the age of an individual.
In this project we explore the possibility that the epigenetic changes that occur during human aging result in dysregulation of transposable elements which contributes to the ageing process. To study this phenomenon, we have during the last decade developed a method to generate human-derived neurons that retain age-associated epigenetic marks. By overexpressing and knocking-down key transcription factors we are able to reprogram human fibroblasts directly into neurons, without going through any rejuvenating pluripotent stage. We think that this model system has the potential to overcome many of the current limitations to study human neuronal aging.
This project is supported by Olle Engkvists stiftelse.