title: The Effects of Cadmium at Low Environmental Concentrations on THP-1 Macrophage Apoptosis.
abstract: Cadmium at environmental concentrations is a risk factor for many diseases, including cardiovascular and neurodegenerative diseases, in which macrophages play an important role. The aim of this study was to evaluate the effects of cadmium at low environmental (nanomolar) concentrations on apoptotic processes in THP-1(acute monocytic leukemia cells line)-derived macrophages, with special focus on mitochondrial events involved. Macrophages were incubated with various cadmium chloride (CdCl₂) solutions for 48 h at final concentrations of 5 nM, 20 nM, 200 nM and 2 µM CdCl₂. Cell viability was measured using flow cytometry. Flow cytometric measurement (annexin V/FITC (annexin V/fluorescein isothiocyanate) and PI (propidium iodide) double staining) was used to quantify the extent of apoptosis. Fluorescence and confocal microscopy were used for imaging of apoptosis process. Changes in mitochondrial membrane potential were monitored using cytofluorimetry after cell staining with JC-1(5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazol-carbocyane iodide) probe. Mitochondrial ROS (reactive oxygen species) levels were measured cytofluorimetrically after incubation of cells with mitochondrial superoxide indicator (MitoSOX) red fluorescent marker. The mRNA expression of Bcl-2 and Bax was analysed with qRT-PCR. Our study demonstrates that cadmium, even at low environmental concentrations, exerts mitochondrial toxicity in THP-1 macrophages. Forty-eight-hour exposure to very low concentrations reduces cell viability and results in cell death by apoptosis and necrosis. The decrease in mitochondrial membrane potential, increased ROS production, increased Bax and decreased Bcl-2 mRNA expression are mitochondrial events involved in cadmium-induced apoptosis.
authors.affiliation: Department of Hygiene and Epidemiology, Pomeranian Medical University, Szczecin 70-111, Poland. tomasz.olszowski@pum.edu.pl.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Olszowski
authors.affiliation: Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Szczecin 70-111, Poland. irena.bosiacka@pum.edu.pl.
authors.forename: Irena
authors.initials: I
authors.lastname: Baranowska-Bosiacka
authors.affiliation: Department of Biochemistry and Human Nutrition, Pomeranian Medical University, Szczecin 71-460, Poland. izagut@poczta.onet.pl.
authors.forename: Izabela
authors.initials: I
authors.lastname: Gutowska
authors.affiliation: Department of Physiology, Pomeranian Medical University, Szczecin 70-111, Poland. piot.kata@gmail.com.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Piotrowska
authors.affiliation: Department of Physiology, Pomeranian Medical University, Szczecin 70-111, Poland. kasia.mierzejewska@gmail.com.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Mierzejewska
authors.affiliation: Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Szczecin 70-111, Poland. jan.korbecki@onet.eu.
authors.forename: Jan
authors.initials: J
authors.lastname: Korbecki
authors.affiliation: Department of Experimental and Clinical Pharmacology, Pomeranian Medical University, Szczecin 70-111, Poland. mkurz@op.pl.
authors.forename: Mateusz
authors.initials: M
authors.lastname: Kurzawski
authors.affiliation: Department of Physiology, Pomeranian Medical University, Szczecin 70-111, Poland. maciejt@sci.pum.edu.pl.
authors.forename: Maciej
authors.initials: M
authors.lastname: Tarnowski
authors.affiliation: Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Szczecin 70-111, Poland. dchlubek@sci.pam.szczecin.pl.
authors.forename: Dariusz
authors.initials: D
authors.lastname: Chlubek
mesh_terms: D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D002104:Cadmium / Q000633:toxicity*; D019256:Cadmium Chloride / Q000633:toxicity; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004785:Environmental Pollutants / Q000633:toxicity*; D015870:Gene Expression; D006801:Humans; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D004785:Environmental Pollutants; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D051028:bcl-2-Associated X Protein; D002104:Cadmium; D019256:Cadmium Chloride
keywords: Bax; Bcl-2; ROS; THP-1 macrophages; apoptosis; cadmium; mitochondrial membrane potential