2Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
3Research Center for Children’s Health, Russian Academy of Medical Sciences, Lomonosovskii pr. 10/16, 119991 Moscow, Russia
* To whom correspondence should be addressed.
Received December 24, 2009; Revision received April 27, 2010
The effects of full-size bovine enteropeptidase (BEK) and of human recombinant light chain enteropeptidase (L-HEP) on survival of cultured hippocampal neurons were studied under conditions of glutamate excitotoxicity. Low concentrations of L-HEP or BEK (0.1-1 and 0.1-0.5 nM, respectively) protected hippocampal neurons against the death caused by 100 µM glutamate. Using the PAR1 (proteinase-activated receptor) antagonist SCH 79797, we revealed a PAR1-dependent mechanism of neuroprotective action of low concentrations of enteropeptidase. The protective effect of full-size enteropeptidase was not observed at the concentrations of 1 and 10 nM; moreover, 10 nM of BEK caused death of 88.9% of the neurons, which significantly exceeded the cell death caused by glutamate (31.9%). Under conditions of glutamate cytotoxicity the survival of neurons was 26.8% higher even in the presence of 10 nM of L-HEP than in the presence of 10 nM BEK. Pretreatment of cells with 10 nM of either form of enteropeptidase abolished the protective effect of 10 nM thrombin under glutamate cytotoxicity. High concentrations of BEK and L-HEP caused the death of neurons mainly through necrosis.
KEY WORDS: enteropeptidase, glutamate toxicity, apoptosis, hippocampal neurons, proteinase activated receptor