title: Bystander effects of PC12 cells treated with Pb²⁺ depend on ROS-mitochondria-dependent apoptotic signaling via gap-junctional intercellular communication.
abstract: The demonstration of bystander effect, which means injured cells propagate damage to neighboring cells, in whole organisms has clear implication of the potential relevance of the non-targeted response to human health. Here we show that 10 μM lead acetate, the optimum concentration for inducing apoptosis confirmed by the expression levels of Bax and Bcl-2, can also induce rat pheochromocytoma (PC12) cells to exert bystander effects to neighboring cells. In a novel co-culture system, GFP-PC12 (Pb(2+)) cells, which were stable transfected with EF1A-eGFP and pre-exposed with lead acetate, were co-cultured with unexposed PC12 cells at a 1:5 ratio. Parachute assays demonstrated the functional gap-junctional intercellular communication (GJIC) formed between Pb(2+)-exposed and unexposed cells. The Pb(2+)-exposed cells induced very similar effects on neighboring unexposed cells to apoptosis coincide with intracellular ROS generation and the collapse of mitochondrial membrane potential (Δψm). Furthermore, carbenoxolone (CBX), a blocker of GJIC, inhibited the bystander effects. The results indicate that the Pb(2+)-induced insults propagate through GJIC between PC12 cells, while inducing the bystander cells to apoptosis via ROS-mitochondria-dependent apoptotic signaling.
authors: Department of Occupational Health and Occupational Medicine, School of Public Health and Tropical Medicine, Southern Medical University, No. 1838, North Guangzhou Road, Guangzhou 510515, PR China; Center for Environmental Health Research, South China Institute of Environmental Sciences, Ministry of Environmental Protection, No. 7 Yuancunxi Street, Guangzhou 510655, PR China.
authors: Shu
authors: S
authors: Guo
authors: Department of Ophthalmology, Guangzhou Women and Children's Medical Center, No. 9 Jinsui Street, Tianhe District, Guangzhou 510623, PR China.
authors: Jin
authors: J
authors: Zhou
authors: Department of Occupational Health and Occupational Medicine, School of Public Health and Tropical Medicine, Southern Medical University, No. 1838, North Guangzhou Road, Guangzhou 510515, PR China.
authors: Xuemei
authors: X
authors: Chen
authors: Center for Environmental Health Research, South China Institute of Environmental Sciences, Ministry of Environmental Protection, No. 7 Yuancunxi Street, Guangzhou 510655, PR China.
authors: Yunjiang
authors: Y
authors: Yu
authors: Center for Environmental Health Research, South China Institute of Environmental Sciences, Ministry of Environmental Protection, No. 7 Yuancunxi Street, Guangzhou 510655, PR China.
authors: Mingzhong
authors: M
authors: Ren
authors: Center for Environmental Health Research, South China Institute of Environmental Sciences, Ministry of Environmental Protection, No. 7 Yuancunxi Street, Guangzhou 510655, PR China.
authors: Guocheng
authors: G
authors: Hu
authors: Center for Environmental Health Research, South China Institute of Environmental Sciences, Ministry of Environmental Protection, No. 7 Yuancunxi Street, Guangzhou 510655, PR China.
authors: Yun
authors: Y
authors: Liu
authors: Department of Occupational Health and Occupational Medicine, School of Public Health and Tropical Medicine, Southern Medical University, No. 1838, North Guangzhou Road, Guangzhou 510515, PR China. Electronic address: zoufei_paper@163.com.
authors: Fei
authors: F
authors: Zou
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D024201:Bystander Effect / Q000187:drug effects*; D002229:Carbenoxolone / Q000494:pharmacology; D002450:Cell Communication / Q000187:drug effects*; D016923:Cell Death / Q000187:drug effects; D018920:Coculture Techniques; D004305:Dose-Response Relationship, Drug; D017629:Gap Junctions / Q000187:drug effects*; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D007854:Lead / Q000633:toxicity*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects*; D009942:Organometallic Compounds / Q000633:toxicity; D016716:PC12 Cells; D020648:Peptide Elongation Factor 1 / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects*; D051028:bcl-2-Associated X Protein / Q000096:biosynthesis
chemical_list: D009942:Organometallic Compounds; D020648:Peptide Elongation Factor 1; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D051028:bcl-2-Associated X Protein; D049452:Green Fluorescent Proteins; D007854:Lead; D002229:Carbenoxolone; C008261:lead acetate
keywords: Apoptosis; Bystander effect; Gap-junctional intercellular communication; Lead acetate; Mitochondrial membrane potential; Reactive oxygen species