Role of transient receptor potential channel 1 (TRPC1) in glutamate-induced cell death in the hippocampal cell line HT22.
Transient receptor potential channel 1 (TRPC1; a cation channel activated by store depletion and/or through an intracellular messenger) is expressed in a variety of tissues, including the brain. To study the physiological function of TRPC1, we investigated the role of endogenously expressed TRPC1 in glutamate-induced cell death, using the murine hippocampal cell line HT22. Knocking down TRPC1 mRNA using TRPC1-shRNA or blocking of TRPC channels using 2-APB (≥200 μM) robustly attenuated glutamate-induced cell death after 24 h of incubation with 5 mM glutamate. Glutamate toxicity in HT22 cells seems to involve metabotropic glutamate receptor mGluR5 since MPEP (2-methyl-6-(phenylethynyl)-pyridine), an mGluR5 antagonist (≥100 μM), abrogated glutamate toxicity. Furthermore, a direct activation of mGluR5 by CHPG [(RS)-chloro-5-hydroxyphenylglycine; 100 μM or 300 μM] promoted HT22 cell death. TRPC1 knock-down markedly reduced CHPG-induced cell death. These observations suggest that glutamate-induced cell death in HT22 cells activates mGluR5 receptors, which significantly increases Ca(2+) influx through TRPC1 channels. TRPC1 knock-down prevented glutamate- and CHPG-induced cell death, suggesting that glutamate-induced toxicity in HT22 cells is mediated through TRPC1 channels and an mGluR5-dependent pathway. Together, this work provides evidence for a novel receptor activation pathway of TRPC1 in glutamate-induced toxicity.
Department of Neurology, Harvard Medical School, Massachusetts General Hospital, Charlestown, MA, 02129-4404, USA.
K Lakshmi
KL
Narayanan
Srinivasa
S
Subramaniam
C Peter
CP
Bengston
Krithi
K
Irmady
Klaus
K
Unsicker
Oliver
O
von Bohlen und Halbach
D000818:Animals; D016923:Cell Death; D002460:Cell Line; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018698:Glutamic Acid / Q000633:toxicity*; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology; D051379:Mice; D009474:Neurons / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D010648:Phenylacetates / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D064529:Receptor, Metabotropic Glutamate 5 / Q000819:agonists / Q000037:antagonists & inhibitors; D050052:TRPC Cation Channels / Q000235:genetics / Q000378:metabolism*
C107349:2-chloro-5-hydroxyphenylglycine; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D010648:Phenylacetates; D011725:Pyridines; D012333:RNA, Messenger; D064529:Receptor, Metabotropic Glutamate 5; D050052:TRPC Cation Channels; C096351:transient receptor potential cation channel, subfamily C, member 1; D018698:Glutamic Acid; C121465:6-methyl-2-(phenylethynyl)pyridine; D005998:Glycine