TY - JOUR
T1 - Involvement of sodium-coupled neutral amino acid transporters (system A) in L-proline transport in the rat retinal pericytes
AU - Zakoji, Nobuyuki
AU - Tajima, Kosuke
AU - Yoneyama, Daisuke
AU - Akanuma, Shin ichi
AU - Kubo, Yoshiyuki
AU - Hosoya, Ken ichi
N1 - Publisher Copyright:
© 2020 The Japanese Society for the Study of Xenobiotics
PY - 2020/10
Y1 - 2020/10
N2 - The retinal pericytes contribute to the supply of collagen to the basement membrane, and thus, form the structural support of the blood-retinal barrier. Since L-proline (L-Pro) is a major component of collagen, the uptake of L-Pro is an important process for the synthesis of collagen. This study was aimed to elucidate L-Pro transport mechanism(s) in the retinal pericytes. The transport of [3H]L-Pro was evaluated in the conditionally immortalized rat retinal pericyte cell line, TR-rPCT1 cells. The expression of the candidate transporter was examined by qualitative/quantitative reverse transcription-polymerase chain reaction, immunoblot analysis, and immunostaining. The [3H]L-Pro uptake by TR-rPCT1 cells showed Na+-dependence, Cl−-independence, and concentration-dependence with a Km of 810 μM. The substrates for system A, such as 2-(methylamino)isobutyric acid (MeAIB), significantly inhibited the L-Pro uptake, suggesting the involvement of system A in the uptake of L-Pro. Among the subtypes of system A, the mRNA expression levels of ATA2 were the highest in TR-rPCT1 cells. Immunostaining analysis of the isolated rat retinal capillaries containing pericytes indicated the protein expression of ATA2 in retinal pericytes. In conclusion, it is suggested that ATA2, at least in part, is involved in the transport of L-Pro in the retinal pericytes.
AB - The retinal pericytes contribute to the supply of collagen to the basement membrane, and thus, form the structural support of the blood-retinal barrier. Since L-proline (L-Pro) is a major component of collagen, the uptake of L-Pro is an important process for the synthesis of collagen. This study was aimed to elucidate L-Pro transport mechanism(s) in the retinal pericytes. The transport of [3H]L-Pro was evaluated in the conditionally immortalized rat retinal pericyte cell line, TR-rPCT1 cells. The expression of the candidate transporter was examined by qualitative/quantitative reverse transcription-polymerase chain reaction, immunoblot analysis, and immunostaining. The [3H]L-Pro uptake by TR-rPCT1 cells showed Na+-dependence, Cl−-independence, and concentration-dependence with a Km of 810 μM. The substrates for system A, such as 2-(methylamino)isobutyric acid (MeAIB), significantly inhibited the L-Pro uptake, suggesting the involvement of system A in the uptake of L-Pro. Among the subtypes of system A, the mRNA expression levels of ATA2 were the highest in TR-rPCT1 cells. Immunostaining analysis of the isolated rat retinal capillaries containing pericytes indicated the protein expression of ATA2 in retinal pericytes. In conclusion, it is suggested that ATA2, at least in part, is involved in the transport of L-Pro in the retinal pericytes.
KW - ATA2
KW - BRB
KW - L-Pro
KW - L-Pro transport
KW - Retinal pericytes
KW - System A
UR - http://www.scopus.com/inward/record.url?scp=85089154020&partnerID=8YFLogxK
U2 - 10.1016/j.dmpk.2020.06.003
DO - 10.1016/j.dmpk.2020.06.003
M3 - 学術論文
C2 - 32771261
AN - SCOPUS:85089154020
SN - 1347-4367
VL - 35
SP - 410
EP - 416
JO - Drug Metabolism and Pharmacokinetics
JF - Drug Metabolism and Pharmacokinetics
IS - 5
ER -