An Atlas of the Quantitative Protein Expression of Anti-Epileptic-Drug Transporters, Metabolizing Enzymes and Tight Junctions at the Blood-Brain Barrier in Epileptic Patients.

Risa Sato,Anthony Bet,Kotaro Ohmori,Mina Umetsu,Mitsutoshi Tano,Brenda Porter,Masaki Takao,Yasuo Uchida,Gerald Grant,Tetsuya Terasaki

doi:10.3390/pharmaceutics13122122

Abstract

The purpose of the present study was to quantitatively elucidate the levels of protein expression of anti-epileptic-drug (AED) transporters, metabolizing enzymes and tight junction molecules at the blood–brain barrier (BBB) in the focal site of epilepsy patients using accurate SWATH (sequential window acquisition of all theoretical fragment ion spectra) proteomics. Brain capillaries were isolated from focal sites in six epilepsy patients and five normal brains; tryptic digests were produced and subjected to SWATH analysis. MDR1 and BCRP were significantly downregulated in the epilepsy group compared to the normal group. Out of 16 AED-metabolizing enzymes detected, the protein expression levels of GSTP1, GSTO1, CYP2E1, ALDH1A1, ALDH6A1, ALDH7A1, ALDH9A1 and ADH5 were significantly 2.13-, 6.23-, 2.16-, 2.80-, 1.73-, 1.67-, 2.47- and 2.23-fold greater in the brain capillaries of epileptic patients than those of normal brains, respectively. The protein expression levels of Claudin-5, ZO-1, Catenin alpha-1, beta-1 and delta-1 were significantly lower, 1.97-, 2.51-, 2.44-, 1.90- and 1.63-fold, in the brain capillaries of epileptic patients compared to those of normal brains, respectively. Consistent with these observations, leakage of blood proteins was also observed. These results provide for a better understanding of the therapeutic effect of AEDs and molecular mechanisms of AED resistance in epileptic patients.

Highlights

Epilepsy is one of the most common central nervous system (CNS) disorders, with an incidence of approximately 1% of the population
Three transporters (MDR1, BCRP and MCT8) and LAT1 are involved in the efflux and influx of anti-epileptic drugs (AEDs) at the blood–brain barrier (BBB), respectively (Table 2) [7,25,26]
The protein expression levels of MDR1 and BCRP were significantly smaller in the epilepsy group than in the normal group

Summary

Introduction

Epilepsy is one of the most common central nervous system (CNS) disorders, with an incidence of approximately 1% of the population. The blood–brain barrier (BBB) regulates the penetration of AEDs into the CNS by forming tight junctions and by expressing drug transporters and drugmetabolizing enzymes. Quantitative analysis of the expression and function of transporters, enzymes and tight junction proteins at the BBB in epilepsy patients is important in terms. Pharmaceutics 2021, 13, 2122 of understanding the therapeutic effects of AEDs, since their penetration is an important factor affecting the therapeutic efficacy of such drugs. It has been reported that the P-glycoprotein (P-gp/MDR1), which is responsible for the efflux of AEDs, is overexpressed in 11 out of 19 epilepsy patients with mRNA expression [4]

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