title: Cigarette Smoke Disturbs the Survival of CD8+ Tc/Tregs Partially through Muscarinic Receptors-Dependent Mechanisms in Chronic Obstructive Pulmonary Disease.
abstract: BACKGROUND
  CD8+ T cells (Cytotoxic T cells, Tc) are known to play a critical role in the pathogenesis of smoking related airway inflammation including chronic obstructive pulmonary disease (COPD). However, how cigarette smoke directly impacts systematic CD8+ T cell and regulatory T cell (Treg) subsets, especially by modulating muscarinic acetylcholine receptors (MRs), has yet to be well elucidated.
  
  
  METHODS
  Circulating CD8+ Tc/Tregs in healthy nonsmokers (n = 15), healthy smokers (n = 15) and COPD patients (n = 18) were evaluated by flow cytometry after incubating with anti-CD3, anti-CD8, anti-CD25, anti-Foxp3 antibodies. Peripheral blood T cells (PBT cells) from healthy nonsmokers were cultured in the presence of cigarette smoke extract (CSE) alone or combined with MRs agonist/antagonist for 5 days. Proliferation and apoptosis were evaluated by flow cytometry using Ki-67/Annexin-V antibodies to measure the effects of CSE on the survival of CD8+ Tc/Tregs.
  
  
  RESULTS
  While COPD patients have elevated circulating percentage of CD8+ T cells, healthy smokers have higher frequency of CD8+ Tregs. Elevated percentages of CD8+ T cells correlated inversely with declined FEV1 in COPD. CSE promoted the proliferation and inhibited the apoptosis of CD8+ T cells, while facilitated both the proliferation and apoptosis of CD8+ Tregs. Notably, the effects of CSE on CD8+ Tc/Tregs can be mostly simulated or attenuated by muscarine and atropine, the MR agonist and antagonist, respectively. However, neither muscarine nor atropine influenced the apoptosis of CD8+ Tregs.
  
  
  CONCLUSIONS
  The results imply that cigarette smoking likely facilitates a proinflammatory state in smokers, which is partially mediated by MR dysfunction. The MR antagonist may be a beneficial drug candidate for cigarette smoke-induced chronic airway inflammation.
authors.affiliation: Department of Respiratory and Critical Care Medicine, Key Laboratory of Pulmonary Diseases of Health Ministry, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Chen
authors.affiliation: Department of Respiratory and Critical Care Medicine, Key Laboratory of Pulmonary Diseases of Health Ministry, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
authors.forename: Mei
authors.initials: M
authors.lastname: Zhou
authors.affiliation: Department of Respiratory and Critical Care Medicine, Key Laboratory of Pulmonary Diseases of Health Ministry, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
authors.forename: Long
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Respiratory and Critical Care Medicine, Key Laboratory of Pulmonary Diseases of Health Ministry, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
authors.forename: Zhao-Ji
authors.initials: ZJ
authors.lastname: Meng
authors.affiliation: Department of Respiratory and Critical Care Medicine, Key Laboratory of Pulmonary Diseases of Health Ministry, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
authors.forename: Xian-Zhi
authors.initials: XZ
authors.lastname: Xiong
authors.affiliation: Department of Respiratory and Critical Care Medicine, Key Laboratory of Pulmonary Diseases of Health Ministry, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
authors.forename: Hong-Ju
authors.initials: HJ
authors.lastname: Liu
authors.affiliation: Department of Respiratory and Critical Care Medicine, Key Laboratory of Pulmonary Diseases of Health Ministry, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
authors.forename: Jian-Bao
authors.initials: JB
authors.lastname: Xin
authors.affiliation: Department of Respiratory and Critical Care Medicine, Key Laboratory of Pulmonary Diseases of Health Ministry, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
authors.forename: Jian-Chu
authors.initials: JC
authors.lastname: Zhang
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D001285:Atropine / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007249:Inflammation / Q000209:etiology*; D008213:Lymphocyte Activation / Q000187:drug effects; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D009116:Muscarine / Q000494:pharmacology; D018721:Muscarinic Agonists / Q000494:pharmacology; D018727:Muscarinic Antagonists / Q000494:pharmacology; D029424:Pulmonary Disease, Chronic Obstructive / Q000276:immunology*; D011976:Receptors, Muscarinic / Q000502:physiology*; D012906:Smoke / Q000009:adverse effects*; D012907:Smoking / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects*; D062789:Tobacco Products
chemical_list: D018721:Muscarinic Agonists; D018727:Muscarinic Antagonists; D011976:Receptors, Muscarinic; D012906:Smoke; D001285:Atropine; D009116:Muscarine