Increased expression of L-amino acid transporters in balloon cells of tuberous sclerosis.
OBJECTIVE
Tuberous sclerosis complex (TSC) is a dysgenetic syndrome involved in multiple organs, and the pathognomonic cortical tuber act as an epileptic substrate. The amino acid transport system L (LAT) is a major nutrient transport system, and LAT1 is highly expressed in malignant tumors to support tumor cell growth. To study the life-long epilepsy from the cortical tuber, the expression of LAT1 in balloon cells and dysplastic neurons of the cortical tuber is investigated.


METHODS
LAT1 expression was investigated by LAT1 mRNA using reverse transcription-polymerase chain reaction and immunohistochemical staining with anti-human LAT1 antibody in nine patients with TSC and three control brains.


CONCLUSIONS
LAT1 mRNA was detectable only in fresh-frozen tissues of TSC, and it was upregulated in the cortical tuber lesion. While the LAT1 immunopositivity of control brains was limited in the capillary endothelial cells in the gray matter, increased LAT1 immunopositivity was noted in balloon cells of the cortical tubers in addition to the capillary endothelial cells as shown in control brains. Linear and strong immunopositivity along the cell membrane and cytoplasm of the balloon cells, and weakly granular immunopositivity in their cytoplasm were noted. Increased expression of LAT1 in the balloon cells is important for the active transport of large neutral amino acids into the balloon cells, and that the biologic process may play an important role in the active protein synthesis with metabolic maintenance of balloon cells in cortical tubers of patients with TSC.
Lim
Byung-Chan
BC
Department of Neurosurgery, Gwangju Christian Hospital, Gwangju, South Korea.
Cho
Kyu-Young
KY
Lim
Joon-Seop
JS
Lee
Rae-Seop
RS
Kim
Hyung-Seok
HS
Kim
Myeong-Kyu
MK
Kim
Jae-Hyoo
JH
Woo
Young-Jong
YJ
Kim
Jong-Keun
JK
Kim
Do Kyung
DK
Kim
Hyung-Ihl
HI
Lee
Kyung-Wha
KW
Lee
Min-Cheol
MC
D000328:Adult; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D027283:Large Neutral Amino Acid-Transporter 1 / Q000096:biosynthesis* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014402:Tuberous Sclerosis / Q000378:metabolism* / Q000473:pathology; D015854:Up-Regulation; D055815:Young Adult
D027283:Large Neutral Amino Acid-Transporter 1; D012333:RNA, Messenger