1. The Lysophosphatidic Acid Type 2 Receptor Is Required for Protection Against Radiation-Induced Intestinal Injury.
- Author
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Deng, Wenlin, E, Shuyu, Tsukahara, Ryoko, Valentine, William J., Durgam, Gangadhar, Gududuru, Veeresa, Balazs, Louisa, Manickam, Venkatraman, Arsura, Marcello, Vanmiddlesworth, Lester, Johnson, Leonard R., Parrill, Abby L., Miller, Duane D., and Tigyi, Gabor
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LYSOPHOSPHOLIPIDS ,PHOSPHOLIPIDS ,INTESTINAL infections ,INTESTINAL diseases - Abstract
Background & Aims: We recently identified lysophosphatidic acid (LPA) as a potent antiapoptotic agent for the intestinal epithelium. The objective of the present study was to evaluate the effect of octadecenyl thiophosphate (OTP), a novel rationally designed, metabolically stabilized LPA mimic, on radiation-induced apoptosis of intestinal epithelial cells in vitro and in vivo. Methods: The receptors and signaling pathways activated by OTP were examined in IEC-6 and RH7777 cell lines and wild-type and LPA
1 and LPA2 knockout mice exposed to different apoptotic stimuli. Results: OTP was more efficacious than LPA in reducing gamma irradiation–, camptothecin-, or tumor necrosis factor α/cycloheximide–induced apoptosis and caspase-3-8, and caspase-9 activity in the IEC-6 cell line. In RH7777 cells lacking LPA receptors, OTP selectively protected LPA2 but not LPA1 and LPA3 transfectants. In C57BL/6 and LPA1 knockout mice exposed to 15 Gy gamma irradiation, orally applied OTP reduced the number of apoptotic bodies and activated caspase-3–positive cells but was ineffective in LPA2 knockout mice. OTP, with higher efficacy than LPA, enhanced intestinal crypt survival in C57BL/6 mice but was without any effect in LPA2 knockout mice. Intraperitoneally administered OTP reduced death caused by lethal dose (LD)100 /30 radiation by 50%. Conclusions: Our data indicate that OTP is a highly effective antiapoptotic agent that engages similar prosurvival pathways to LPA through the LPA2 receptor subtype. [Copyright &y& Elsevier]- Published
- 2007
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