AUTHOR=Pärn Angela , Olsen Ditte , Tuvikene Jürgen , Kaas Mathias , Borisova Ekaterina , Bilgin Mesut , Elhauge Mie , Vilstrup Joachim , Madsen Peder , Ambrozkiewicz Mateusz C. , Goz Roman U. , Timmusk Tõnis , Tarabykin Victor , Gustafsen Camilla , Glerup Simon TITLE=PCSK9 deficiency alters brain lipid composition without affecting brain development and function JOURNAL=Frontiers in Molecular Neuroscience VOLUME=15 YEAR=2023 URL=https://www.frontiersin.org/journals/molecular-neuroscience/articles/10.3389/fnmol.2022.1084633 DOI=10.3389/fnmol.2022.1084633 ISSN=1662-5099 ABSTRACT=
PCSK9 induces lysosomal degradation of the low-density lipoprotein (LDL) receptor (LDLR) in the liver, hereby preventing removal of LDL cholesterol from the circulation. Accordingly, PCSK9 inhibitory antibodies and siRNA potently reduce LDL cholesterol to unprecedented low levels and are approved for treatment of hypercholesterolemia. In addition, PCSK9 inactivation alters the levels of several other circulating lipid classes and species. Brain function is critically influenced by cholesterol and lipid composition. However, it remains unclear how the brain is affected long-term by the reduction in circulating lipids as achieved with potent lipid lowering therapeutics such as PCSK9 inhibitors. Furthermore, it is unknown if locally expressed PCSK9 affects neuronal circuits through regulation of receptor levels. We have studied the effect of lifelong low peripheral cholesterol levels on brain lipid composition and behavior in adult PCSK9 KO mice. In addition, we studied the effect of PCSK9 on neurons in culture and