title: Non-neuronal muscarinic receptor activation prevents apoptosis of endothelial cells induced by homocysteine.
abstract: OBJECTIVE
  Endothelial apoptosis plays an important role in the initiation of atherosclerosis. It would be useful to clarify whether activation of non-neuronal muscarinic receptor (NNMR) could prevent endothelial apoptosis and atherosclerosis. We investigated the effects of NNMR activation on regulating rat aortic endothelial cells (RAECs) apoptosis induced by homocysteine, an independent risk factor of atherosclerosis, and further studied its molecular mechanism.
  
  
  METHODS
  RAECs were incubated using homocysteine at the concentration of 2.7 mmol/L for 36 h. RAECs were also pre-treated with carbachol or arecoline to examine their effects. RT-PCR was used to assess changes in the gene expression related to cell apoptosis.
  
  
  RESULTS
  Incubation of RAECs with homocysteine at the concentration of 2.7 mmol/L resulted in morphologic changes, such as cellular shrinkage, membrane blebbing, chromatin condensation and margination. These could be attenuated by pretreatment with carbachol and arecoline at the concentration of 10 micromol/L for 12 h. Homocysteine induced apoptosis in RAECs and the molecular mechanisms were associated with the regulation of fas, fas-L and caspase-8 in the death receptor pathway, bcl-2, bcl-xL and bax in the mitochondrial pathway, caspase-12 in the endoplasmic reticulum pathway and caspase-3, caspase-6 and p53 as downstream effectors. Carbachol and arecoline attenuated the effects of homocysteine on genes in the death receptor pathway, in the mitochondrial pathway and in the downstream pathway. Atropine could reverse all of the effects of arecoline.
  
  
  CONCLUSIONS
  Activation of NNMR by carbacol and arecoline inhibits homocysteine-induced endothelial cell apoptosis mainly through regulation of death receptor pathway, mitochondrial pathway and downstream effectors.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Chao-Liang
authors.initials: CL
authors.lastname: Long
authors.forename: Zhi-Yuan
authors.initials: ZY
authors.lastname: Pan
authors.forename: Yuan-Yuan
authors.initials: YY
authors.lastname: Zhang
authors.forename: Hai
authors.initials: H
authors.lastname: Wang
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D001115:Arecoline; D002217:Carbachol; D002453:Cell Cycle; D004721:Endoplasmic Reticulum / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology* / Q000187:drug effects; D006710:Homocysteine / Q000009:adverse effects*; D008928:Mitochondria / Q000378:metabolism; D051381:Rats; D011976:Receptors, Muscarinic / Q000378:metabolism*
chemical_list: D051017:Apoptosis Regulatory Proteins; D011976:Receptors, Muscarinic; D006710:Homocysteine; D001115:Arecoline; D002217:Carbachol