Up-regulation of L type amino acid transporter 1 after spinal cord injury in rats.
BACKGROUND
L-type amino acid transporter 1 (LAT1) is proposed to be a major nutrient transporter at the blood brain barrier. LAT1 requires the heavy chain of 4F2 cell surface antigen (4F2hc) for functional expression.


METHODS
We investigated the expression of this heterodimeric transporter after traumatic spinal cord injury in rat by using immunohistochemical and western blot analyses.


RESULTS
LAT1 immunoreactivities were up-regulated in the capillary endothelia in close to the injury epicenter 24 hours after injury. It reached a peak at 48 hours after injury, and thereafter decreased. 4F2hc was abundant and unchanged all through the time course after SCI. Western blot analysis under reductive and non-reductive conditions showed that LAT1 and 4F2hc were conjugated as a heterodimeric transporter and the functional regulation was dependent on the light chain, LAT1.


CONCLUSIONS
We suggest that LAT1 may be transiently upregulated as part of the tissue-repair process after traumatic contusion injury in the spinal cord.
Toyooka
Terushige
T
Department of Neurosurgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan. teru-toy@mse.biglobe.ne.jp
Nawashiro
Hiroshi
H
Shinomiya
Nariyoshi
N
Yano
Akiko
A
Ooigawa
Hidetoshi
H
Ohsumi
Atsushi
A
Uozumi
Yoichi
Y
Yanagawa
Youichi
Y
Matsuo
Hirotaka
H
Shima
Katsuji
K
D027062:Amino Acid Transport System L / Q000378:metabolism*; D000704:Analysis of Variance; D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D027282:Fusion Regulatory Protein 1, Heavy Chain / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000378:metabolism; D013119:Spinal Cord Injuries / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D013997:Time Factors; D015854:Up-Regulation / Q000502:physiology*
D027062:Amino Acid Transport System L; D027282:Fusion Regulatory Protein 1, Heavy Chain