Drug Transport Mechanisms at the Blood-CSF Barrier and Effect of Aging

研究总结

Research Summary Brain disorders, especially age-related neurological diseases, constitute a major public health problem in the developed world. Despite the urging needs for new and more effective drugs to treat brain diseases, development of CNS drugs remains challenging. To exert their therapeutic effects, CNS-targeted drugs must cross the brain-blood barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB) and maintain minimal effective concentrations in the brain. The BBB and BCSFB are not only physical barriers but also express a spectrum of multispecific drug transporters to actively remove drugs and other xenobiotics from the brain. The choroid plexus epithelial (CPE) cells forming the BCSFB play an essential role in brain removal of drugs and metabolites through secretion of the CSF and active transport of solutes from the CSF into the blood circulation. Nevertheless, little is known regarding the molecular and cellular mechanisms governing drug transport show marked morphological and functional changes developed a live tissue imaging approach in isolated murine choroid plexus to analyze organic anion and cation transport processes in CPE cells. Our processes at the BCSFB. Furthermore, the CPE cells are known to changes during aging but it is unknown if these age-dependent impact the expression and activity of transporters at the BCSFB. Our laboratory recently preliminary studies suggest that large amphipathic organic anions (OAs) are rapidly cleared from the CSF side into the blood capillary side by a highly functional BCSFB transport system likely consisting of organic anion transporting polypeptides (Oatps) at the apical membrane and multidrug resistance-associated proteins (Mrps) at the basolateral membrane. We hypothesize that Oatps mediate the first and rate-limiting step in the transport of structurally diverse amphipathic OAs across the BCSFB and that the expression and activity of Oatps and Mrps at the BCSFB are regulated by aging. The goals of this application are to determine the functional characteristics of the BCSFB amphipathic OA transport system, define the role of Oatp1a transporters in BCSFB transport, and explore age-dependent changes in transporter expression and function at the BCSFB. The proposed studies will build a functional and mechanistic framework for a major xenobiotic clearance pathway at the BCSFB and pave the way for future studies to investigate the impact of BCSFB transporters and aging on CNS drug disposition, pharmacokinetics and pharmacodynamics.