Tributyltin (TBT) salts are well known skin irritants in rodents and humans. TBT induced both the intracellular production of interleukin-1α (IL-1α) and its release into culture medium in a murine keratinocyte cell line (HEL30). Here, we report that mitochondria are important for TBT-induced IL-1α production. Confluent cells were treated with increasing concentrations of TBT (0-2.5 μM) or dimethylsulfoxide as vehicle control. At different times thereafter (0-24 h), nuclear extracts were analyzed for nuclear factor-κB (NF-κB) binding activity by electrophoretic mobility shift assay, and the released and cell-associated IL-1α was measured by enzyme-linked immunosorbent assay. TBT induced a direct and concentration-related activation of NF-κB, which peaked at 2 h and was blocked by pyrrolidinedithiocarbamate, a potent NF-κB inhibitor, and rotenone, an inhibitor of the electron entry from complex I to ubiquinone. Rotenone also induced a concentration-related inhibition of IL-1α synthesis induced by TBT, but rotenone did not completely abrogate TBT-induced IL-1α production, which suggests that other transcription factors may be involved in IL-1α production. Prolonged treatment with ethidium bromide, an inhibitor of mitochondrial DNA and RNA synthesis, was used to partially deplete cells of functional mitochondria. After 5 d of treatment, mitochondrial conversion of tetrazolium bromide to formazan was reduced by 50%, and IL-1α release was decreased by 65%, whereas no induction of intracellular IL-1α was observed. This effect was not due to inhibition of protein synthesis, because identical incorporation of [3H]leucine into protein in control and ethidium bromide-treated cells was identical. This impairment of mitochondrial metabolism inhibited NF-κB activation by TBT. These findings indicate that mitochondria may be the source of second messenger molecules important for TBT-induced IL-1α production.

Role of mitochondria in tributyltin-induced interleukin-1α production in murine keratinocytes / E. Corsini, C. Schubert, M. Marinovich, C.L. Galli. - In: JOURNAL OF INVESTIGATIVE DERMATOLOGY. - ISSN 0022-202X. - 107:5(1996 Nov), pp. 720-725.

Role of mitochondria in tributyltin-induced interleukin-1α production in murine keratinocytes

E. Corsini
Primo
;
M. Marinovich
Penultimo
;
C.L. Galli
Ultimo
1996

Abstract

Tributyltin (TBT) salts are well known skin irritants in rodents and humans. TBT induced both the intracellular production of interleukin-1α (IL-1α) and its release into culture medium in a murine keratinocyte cell line (HEL30). Here, we report that mitochondria are important for TBT-induced IL-1α production. Confluent cells were treated with increasing concentrations of TBT (0-2.5 μM) or dimethylsulfoxide as vehicle control. At different times thereafter (0-24 h), nuclear extracts were analyzed for nuclear factor-κB (NF-κB) binding activity by electrophoretic mobility shift assay, and the released and cell-associated IL-1α was measured by enzyme-linked immunosorbent assay. TBT induced a direct and concentration-related activation of NF-κB, which peaked at 2 h and was blocked by pyrrolidinedithiocarbamate, a potent NF-κB inhibitor, and rotenone, an inhibitor of the electron entry from complex I to ubiquinone. Rotenone also induced a concentration-related inhibition of IL-1α synthesis induced by TBT, but rotenone did not completely abrogate TBT-induced IL-1α production, which suggests that other transcription factors may be involved in IL-1α production. Prolonged treatment with ethidium bromide, an inhibitor of mitochondrial DNA and RNA synthesis, was used to partially deplete cells of functional mitochondria. After 5 d of treatment, mitochondrial conversion of tetrazolium bromide to formazan was reduced by 50%, and IL-1α release was decreased by 65%, whereas no induction of intracellular IL-1α was observed. This effect was not due to inhibition of protein synthesis, because identical incorporation of [3H]leucine into protein in control and ethidium bromide-treated cells was identical. This impairment of mitochondrial metabolism inhibited NF-κB activation by TBT. These findings indicate that mitochondria may be the source of second messenger molecules important for TBT-induced IL-1α production.
Settore BIO/14 - Farmacologia
http://www.ncbi.nlm.nih.gov/pubmed/8875956
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/181492
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