University of Louisville
Arsenic Exposure Increases IL-8 Expression and Leukocyte Transmigration in Endothelial Cells
Institution
University of Louisville
Faculty Advisor/ Mentor
Stanley D’Souza
Abstract
Chronic arsenic exposure through contaminated drinking water is a worldwide health problem. In several recently published studies, mice exposed to inorganic arsenic (1- 10 ppm) via drinking water showed an increase in atherosclerotic lesions along the aortic tree that contained high amounts of leukocytes. Organic arsenic (Monomethylarsonous acid, MMAIII), a metabolite generated from inorganic arsenic, is highly toxic at lower concentrations in cultured cells. To determine the potential mechanism by which arsenic induces an increase in leukocyte accumulation in the atherosclerotic lesions, we hypothesized that arsenic exposure compromises the permeability of the vasculature, thereby increasing the transmigration(TM) of leukocytes through the Endothelial Cells (EC). Initially, we determined the viability of EC at various concentrations of MMAIII. Our results indicated that MMAIII exposure at higher concentrations (1-2nM) resulted in greater levels of cell toxicity, while at lower concentrations (0.25-0.5nM) EC were less affected. EC were exposed to MMAIII (0.25nM-1nM) for 0-48h. The levels of interleukin-8 (IL-8), a chemokine known to increase the permeability of EC, were measured by ELISA. Leukocyte TM was assessed using a transwell assay. An increase in IL-8 levels was found. Post 24h the IL-8 levels for the control was 268pg/mL, at 0.5nM it was 320 pg/mL (p≤0.78) and at 1nM it was 445 pg/mL (p ≤0.15). A dose-dependent increase in leukocyte TM through EC exposed to MMAIII was observed. Post 24h, at 0.25nM there was a 0.52 fold increase (p ≤0.03), while at 0.5nM there was a 0.97 fold increase (p ≤0.01), and most dramatically at 1nM there was a 1.43 fold increase (p ≤0.01) in TM. Based on the compilation and analysis of the above results, we concluded that MMAIII exposure to EC resulted in vascular dysfunction leading to an increase in TM of leukocytes, which may be in part due to an increase in IL-8 induction.
Arsenic Exposure Increases IL-8 Expression and Leukocyte Transmigration in Endothelial Cells
Chronic arsenic exposure through contaminated drinking water is a worldwide health problem. In several recently published studies, mice exposed to inorganic arsenic (1- 10 ppm) via drinking water showed an increase in atherosclerotic lesions along the aortic tree that contained high amounts of leukocytes. Organic arsenic (Monomethylarsonous acid, MMAIII), a metabolite generated from inorganic arsenic, is highly toxic at lower concentrations in cultured cells. To determine the potential mechanism by which arsenic induces an increase in leukocyte accumulation in the atherosclerotic lesions, we hypothesized that arsenic exposure compromises the permeability of the vasculature, thereby increasing the transmigration(TM) of leukocytes through the Endothelial Cells (EC). Initially, we determined the viability of EC at various concentrations of MMAIII. Our results indicated that MMAIII exposure at higher concentrations (1-2nM) resulted in greater levels of cell toxicity, while at lower concentrations (0.25-0.5nM) EC were less affected. EC were exposed to MMAIII (0.25nM-1nM) for 0-48h. The levels of interleukin-8 (IL-8), a chemokine known to increase the permeability of EC, were measured by ELISA. Leukocyte TM was assessed using a transwell assay. An increase in IL-8 levels was found. Post 24h the IL-8 levels for the control was 268pg/mL, at 0.5nM it was 320 pg/mL (p≤0.78) and at 1nM it was 445 pg/mL (p ≤0.15). A dose-dependent increase in leukocyte TM through EC exposed to MMAIII was observed. Post 24h, at 0.25nM there was a 0.52 fold increase (p ≤0.03), while at 0.5nM there was a 0.97 fold increase (p ≤0.01), and most dramatically at 1nM there was a 1.43 fold increase (p ≤0.01) in TM. Based on the compilation and analysis of the above results, we concluded that MMAIII exposure to EC resulted in vascular dysfunction leading to an increase in TM of leukocytes, which may be in part due to an increase in IL-8 induction.