NOMIS Awardee Tony Wyss-Coray, Andrew Yang and colleagues have identified a method for isolating and analyzing the elusive cells of the blood–brain barrier to map the expression of genes in the blood vessels of the human brain. Unravelling the molecular basis of this vasculature expands our understanding of overall brain health, disease and treatment. Their work was published in Nature.
The problem
The adult human brain has roughly 650 kilometres of blood vessels, making it the organ with the greatest vascularization in the body. The vasculature’s involvement in the exchange of molecules between the brain and the rest of the body make it an important system both biologically and pharmacologically. It is involved in most brain diseases, yet it remains understudied. Furthermore, although studies in mice have led to progress in this area, the translatability from mice to humans is unclear.
We think the reason for this lack of progress is that vascular cells and nuclei are difficult to recover from human post-mortem brain tissue, because the nuclei remain stuck in the basement membrane — the sheet-like extracellular matrix that provides the structure of microvessels. As a result, a molecular map of the human brain vasculature has, to our knowledge, not yet been developed.
The solution
Given the system’s importance in neurodegeneration, we set out to create a single-cell molecular atlas of the human brain vasculature in health and Alzheimer’s disease. Inspired by developments in single-cell RNA sequencing and the profiling of nuclei from non-vascular cells released from archived, frozen brains, we attempted to apply these methods to the human brain vasculature. We tried various chemical, enzymatic and physical approaches; after many unsuccessful attempts, we were able to adapt a method used for splenocyte isolation and combine it with our existing methods for isolating brain cells and cleaning up debris. We have called this method VINE-seq, for ‘vessel isolation and nuclei extraction for sequencing’. Once the process was optimized, we analysed 25 samples from either the cortex or hippocampus from individuals with Alzheimer’s disease and from people with no cognitive impairment.
Continue reading this Nature Briefing: Molecular map of the human blood–brain barrier reveals links to Alzheimer’s disease
Read the Nature publication: A human brain vascular atlas reveals diverse mediators of Alzheimer’s risk
