[Effect of lysophosphatidic acid increase the permeability of blood-brain barrier model].
OBJECTIVE
To explore if lysophosphatidic acid (LPA) can regulate the permeability of blood-brain barrier (BBB) and the possible mechanism.


METHODS
Astrocytes and blood microvascular endothelial cells (BMECs) of neonatal SD rat were co-cultured to establish BBB model in vitro. The BBB models were divided randomly into 3 groups: blank control group (Group C), LPA group (Group L, treated with LPA 10 micromol/L for 2 h), and Ro31-8220 plus LPA group. (Group Ro + L, pretreated with Ro31-8220, a selective protein kinase inhibitor 5 micromol/L for 2 h and then treated with LPA 10 micromol/L for 2 h). 12I-bovine serum albumin (BSA) was added into the culture fluid of the BBB models and then the permeability of the BBB models was detected by gamma-events-per-unit-time meter. The cells expressing PKC-alpha were detected by flow cytometry (FCM). Phalloidin staining and fluorescence microscopy were used to detect the expression of F-actin. The BBB-tight-junction (TJ) was observed by electron microscopy. The expression of claudin-5 was detected by Western blotting.


RESULTS
The throughput of 125I-BSA of Group L was 364 cmp +/- 15 cmp, significantly higher than those of the Group C and Group RO + L (184 cmp +/- 10 cmp and 223 cmp 9 cmp respectively, both P < 0.01). FCM showed that the rate of PKC-alpha expressing-BMECs of Group L was 77% +/- 7%, significantly higher than those of Groups C and Ro + L (42% +/- 4% and 52% +/- 3% respectively, both P < 0.01). The claudin-5 expression of Group L was 0.035 +/- 0.004, significantly lower than those of Groups C and Ro + L (1.00 +/- 0.03 and 0. 574 +/- 0.07 respectively, both P < 0.01). Phalloidin staining showed that a zone of F-actin filaments in Group C, intercellular spaces were seen in Group L, and F-actin filaments were recombined in Group Ro + L. Transmission electron microscopy showed that there was continuous high-density BBB-TJ in Group C, the BBB-TJ of Group L was obviously opened, and the BBB-TJ of Group Ro + L was partially opened at a lower degree.


CONCLUSIONS
LPA accommodates the BBB-TJ and the permeability of BBB via the activation of PKC-alpha channel which down-regulates the caudin-5 expression and F-actin recombination. Lysophosphatidic acid;
Gan
Na
N
Department of Pediatrics, Xiangya Hospital, Central-South University, Changsha 410008, China. ganna4050@163.com
Yin
Fei
F
Peng
Jing
J
Wang
Wei-Dong
WD
D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D001812:Blood-Brain Barrier / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D002199:Capillary Permeability / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D002478:Cells, Cultured; D018920:Coculture Techniques; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D008246:Lysophospholipids / Q000494:pharmacology*; D008565:Membrane Proteins / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects
D004791:Enzyme Inhibitors; D007211:Indoles; D008246:Lysophospholipids; D008565:Membrane Proteins; D011493:Protein Kinase C; C032881:lysophosphatidic acid; C064758:Ro 31-8220