Key result
The choroid plexus produces and secretes functional renin into the cerebrospinal fluid, and its activity increases with age independently of circulating plasma renin.
Why the study?
The presence and functional activity of renin in the central nervous system remains controversial due to disputed identification of functional renin.
The renin–angiotensin system is important in cardiovascular and brain physiology. The local brain RAS was proposed over 50 years and decades of research support its existence. However, it remains controversial primarily due to disputed identification of functional renin in the central nervous system. Here, we show that functional renin is produced and released by the choroid plexus, the primary source of cerebrospinal fluid in the brain. Across public RNA sequencing datasets, renin is expressed in both mouse and human choroid plexus epithelial cells, and its expression is validated by RNAscope, immunofluorescence, qPCR, and western blotting. We further demonstrate renin activity in human cerebrospinal fluid that is independent of either circulating renin or blood–brain barrier integrity and confirm its release and activity from mouse choroid plexus explants. Notably, cerebrospinal fluid renin activity but not plasma renin activity increases with aging in human adults. These findings identify the choroid plexus as a source of renin in the central nervous system and provide evidence supporting a local functional brain renin angiotensin system.
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Santisteban et al. (2026) studied this question. Choroid plexus renin production was evaluated on Renin expression and functional activity in the choroid plexus and cerebrospinal fluid. The choroid plexus produces and secretes functional renin into the cerebrospinal fluid, and its activity increases with age independently of circulating plasma renin.
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