TNF-α expression patterns as potential molecular biomarker for human skin cells exposed to vesicant chemical warfare agents: sulfur mustard (HD) and Lewisite (L)

Abstract

Studies were conducted to examine the effect of two vesicant chemical warfare agents (VCWA), one of them an arsenical, on cytokine gene expression in normal human epidermal keratinocyte (NHEK) cells. We tested 2,2′-dichlorethylsulfide (sulfur mustard, military designation HD) and 2,chlorovinyldichloroarsine (Lewisite, military designation L), which have significant differences in their chemical, physical, and toxicological properties. Human tumor necrosis factor-alpha (hTNF-α) cytokine was detected by using the enzyme-linked immunosorbent assay, a protein multiplex immunoassay, Luminex^100™, and reverse transcription-polymerase chain reaction (RT-PCR). The messenger RNA expression of hTNF-α was determined to provide a semi-quantitative analysis. HD-stimulated NHEK induced secretion of hTNF-α in a dose-dependent manner. Dose response effect of Lewisite decreased hTNF-α levels. Time-response data indicated that the maximum response for HD occurred at 24 h with an associated cytotoxic concentration of 10^–4 mol/L. NHEK cells stimulated with 10^–4 mol/L HD for 24 h at 37°C increased detectable levels of hTNF-α from 5 to 28 ng/ml at an index of cell viability between 85 to 93% as detected by Luminex^100™. Our results indicated that the increased levels of hTNF-α by HD are dependent on the primary cultures, cell densities, and chemical properties of the stimulation. Lewisite under the same conditions as HD caused a reduction of hTNF-α from control levels of 1.5 ng/ml to 0.3 ng/ml after stimulation (10^–4 mol/L), with an index of cell viability of ∽34%. We analyzed the transcriptional of hTNF-α gene and found that HD (10^–6 to 10^–4 mol/L) activates hTNF-α gene in cultured NHEK and that L at 10^–6 to 10^–4 mol/L markedly reduces hTNF-α gene. We conclude that the pro-inflammatory mediator, hTNF-α, could be a potential biomarker for differentiating between exposure of HD or L.