Brain Pericytes Enhance MFSD2A Expression and Plasma Membrane Localization in Brain Endothelial Cells Through the PDGF-BB/PDGFRβ Signaling Pathway.

The brain actively obtains nutrients through various transporters on brain microvessel endothelial cells (BMECs). Major facilitator superfamily domain-containing protein 2a (MFSD2A) serves as a key transporter of docosahexaenoic acid (DHA) at the blood-brain barrier (BBB) and is exclusively expressed in BMECs. Although brain pericytes (PCs) regulate MFSD2A expression in BMECs, the underlying mechanism remains unclear. To determine whether PDGF-BB/PDGFRβ signaling between endothelial cells (ECs) and PCs affects MFSD2A protein expression and plasma membrane localization in ECs, we examined the impact of AG1296 (a PDGF receptor inhibitor) and Pdgfrb-knockdown PCs on a non-contact coculture BBB model comprising the primary cultures of rat brain ECs and PCs. The effects of PCs on MFSD2A expression, localization, and brain endothelial DHA uptake was assessed using Western blot, immunofluorescence staining, and [(14)C]DHA uptake by ECs, respectively. In ECs cocultured with PCs, MFSD2A expression and plasma membrane localization were significantly higher than in EC monolayers. Moreover, conditioned medium derived from PCs failed to enhance MFSD2A expression. The increased expression and membrane localization of MFSD2A were inhibited by AG1296 and Pdgfrb-knockdown PCs. Furthermore, PCs significantly increased [(14)C]DHA uptake by ECs. These findings suggest that PCs enhance MFSD2A expression and plasma membrane localization in ECs through PDGF-BB/PDGFRβ signaling.