title: Ambient fine particles (PM2.5) attenuate collagen-induced platelet activation through interference of the PLCγ2/Akt/GSK3β signaling pathway.
abstract: OBJECTIVE
  It has been proven that carbon nanoparticles or diesel exhaust particles stimulate platelet activation. However, the effect of fine particle matter (PM2.5) on platelet activation remains unknown, which motivates this study.
  
  
  METHODS
  PM2.5samples were collected in an urban area of Zhengzhou, China. To study the morphological characteristics and the mass concentrations of trace elements of PM2.5samples, a filed-emission scanning electron microscope, the Image-J software, and an inductively coupled plasma mass spectrometry were used. Washed human platelets or platelet-rich-plasma were used to study the effect of PM2.5on platelet aggregation, P-selectin expression, or platelet signaling pathways. The cytotoxicity in platelets exposed to PM2.5was evaluated by a lactate dehydrogenase assay kit. In addition, platelet adhesion and spreading were studied on collagen-coated surfaces in stable conditions.
  
  
  RESULTS
  The filed-emission scanning electron microscope scanning showed that PM2.5samples varied in shape and size distributions. The mean equivalent spherical diameter of these particles was 1.97 ± 0.04 μm, of which 82.40% were particles with equivalent spherical diameters of less than 2.5 μm. The mass concentration of Ca was higher than that of other elements. The other elements followed the trend of Al>Fe>Zn>Mg>Pb>K>Mn>Cu>Ti>Ba>As>Sr>Sn>Sb>Cd>B>Se>Mo>Ag>Ni>TI>V>Co. Furthermore, pretreatment of PM2.5significantly inhibited rather than potentiated collagen-induced platelet aggregation and P-selectin expression, whereas it had no significant effect on ADP-induced platelet aggregation and P-selectin expression. The lactate dehydrogenase analysis showed trivial cytotoxic effect of PM2.5exposure on platelets. Pretreatment of PM2.5inhibited platelet adhesion on immobilized collagen-coated surfaces; however, it almost did not impact the platelet spreading. Immunoblotting analysis indicated that PM2.5reduced collagen-induced phosphorylation of phospholipase C gamma-2 (PLCγ2) at Tyr759, Akt at Ser473, and glycogen synthase kinase 3β (GSK3β) at Ser9.
  
  
  CONCLUSIONS
  PM2.5attenuated collagen-induced platelet aggregation, α-granule secretion and adhesion, with the potential mechanism of impairing PLCγ2, Akt, and GSK3β signaling. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 530-540, 2017.
authors.affiliation: Department of Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, People's Republic of China.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Yin
authors.affiliation: Department of Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, People's Republic of China.
authors.forename: Hai-Jiang
authors.initials: HJ
authors.lastname: Xu
authors.affiliation: Department of Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, People's Republic of China.
authors.forename: Xia-Li
authors.initials: XL
authors.lastname: Yao
authors.affiliation: Department of Nutrition and Food Hygiene, Chronic Disease Research Institute, Zhejiang University School of Public Health, Hangzhou, People's Republic of China.
authors.forename: Gang
authors.initials: G
authors.lastname: Liu
authors.affiliation: Department of Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, People's Republic of China.
authors.forename: Chun-Jie
authors.initials: CJ
authors.lastname: Nie
authors.affiliation: Department of Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, People's Republic of China.
authors.forename: Han
authors.initials: H
authors.lastname: Wei
authors.affiliation: Department of Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, People's Republic of China.
authors.forename: Cai
authors.initials: C
authors.lastname: Li
authors.affiliation: Department of Pharmacology, School of Basic Medicine, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China.
authors.forename: Ming-Lu
authors.initials: ML
authors.lastname: Liang
authors.affiliation: Department of Pharmacology, School of Basic Medicine, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China.
authors.forename: Zhang-Yin
authors.initials: ZY
authors.lastname: Ming
authors.affiliation: Department of Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, People's Republic of China.
authors.forename: Xiao-Jian
authors.initials: XJ
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000633:toxicity*; D001792:Blood Platelets / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D002681:China; D003094:Collagen / Q000494:pharmacology*; D005260:Female; D000071679:Glycogen Synthase Kinase 3 beta / Q000378:metabolism; D006801:Humans; D008297:Male; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D019007:P-Selectin / Q000378:metabolism; D052638:Particulate Matter / Q000633:toxicity*; D051966:Phospholipase C gamma / Q000378:metabolism; D015539:Platelet Activation / Q000187:drug effects*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D014131:Trace Elements / Q000032:analysis; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D019007:P-Selectin; D052638:Particulate Matter; D014131:Trace Elements; D003094:Collagen; D000071679:Glycogen Synthase Kinase 3 beta; D051057:Proto-Oncogene Proteins c-akt; D051966:Phospholipase C gamma
keywords: Akt/GSK3β; PLCγ2; PM2.5; platelet activation