In our study, we used immunofluorescence to examine brain endothelial cells (ECs) from Slc3a2 ECKO mice and found that blood-brain barrier markers, including tight junction proteins and transcytosis-associated proteins, exhibited significant changes compared to Slc3a2 WT mice. To further investigate these findings, we performed flow cytometry sorting on brain ECs from both Slc3a2 WT and ECKO mice. Subsequently, we conducted proteomic sequencing to identify additional molecular changes, particularly those related to blood-brain barrier markers.