Evidence for cellular protein covalent binding derived from styrene metabolite

Abstract

Styrene is one of the most important industrial intermediates consumed in the world. Human exposure to styrene occurs mainly in the reinforced plastics industry, particularly in developing countries. Styrene has been found to be hepatotoxic and pneumotoxic in humans and animals. The biochemical mechanisms of styrene-induced toxicities remain unknown. Albumin and hemoglobin adduction derived from styrene oxide, a major reactive metabolite of styrene, has been reported in blood samples obtained from styrene exposed workers. The objectives of the current study focused on cellular protein covalent binding of styrene metabolite and its correlation with cytotoxicity induced by styrene. We found that radioactivity was bound to cellular proteins obtained from mouse airway trees after incubation with 14C-styrene. Microsomal incubation studies showed that the observed protein covalent binding required the metabolic activation of styrene. The observed radioactivity binding in protein samples obtained from the cultured airways and microsomal incubations were significantly suppressed by co-incubation with disulfiram, a CYP2E1 inhibitor, although disulfiram apparently did not show a protective effect against the cytotoxicity of styrene. A 2-fold increase in radioactivity bound to cellular proteins was detected in cells stably transfected with CYP2E1 compared to the wild-type cells after 14C-styrene exposure. With the polyclonal antibody developed in our lab, we detected cellular protein adduction derived from styrene oxide at cysteinyl residues in cells treated with styrene. Competitive immunoblot studies confirmed the modification of cysteine residues by styrene oxide. Cell culture studies showed that the styrene-induced protein modification and cell death increased with the increasing concentration of styrene exposure. In conclusion, we detected cellular protein covalent modification by styrene oxide in microsomal incubations, cultured cells, and mouse airways after exposure to styrene and found a good correlation between styrene-induced cytotoxicity and styrene oxide-derived cellular protein adduction.

Polymer Conjugates of Photoinducible CO‐Releasing Molecules

“…[55,56] More interestingly, the polymer conjugate Mn(CO) 3 @P2 shows cytotoxic activity, whereas none of the bpma-type ligands nor the polymer P2 shows marked toxicity. Similar behaviour has been observed in conjugates of cymantrene, CpMn(CO) 3 , with cell-penetrating peptides.…”

Serum Cytokeratin 18 and Cytokine Elevations Suggest A High Prevalence of Occupational Liver Disease in Highly Exposed Elastomer/Polymer Workers

“…While acrylonitrile is metabolized into cyanide, a potent inhibitor of cytochrome c oxidase; 1,3 butadiene and styrene are metabolized into reactive intermediates including crotonaldehyde and styrene 7,8-oxide (15–17). Regardless of its etiology, steatohepatits is invariably associated with mitochondrial dysfunction, oxidative stress and elevated pro-inflammatory cytokines (1, 11, 18, 19).…”

Structure-toxicity relationship study of para-halogenated styrene analogues in CYP2E1 transgenic cells

“…Transgenic cell line expressing CYP2E1 (h2E1) and the wild-type cell line (cHo1, human B-lymphoblastoid) were obtained from BD-Gentest (Palo Alto, CA). The cell lines were used in our earlier styrene toxicity studies (Chung et al ., 2006; Yuan et al ., 2010). Recombinant human CYP2E1 was purchased from BD-Gentest (Palo Alto, CA).…”

“…Parental and h2E1 cells were cultured in RPMI 1640 supplemented with L-glutamine and 10% fetal bovine serum (Hyclone Laboratory, Logan, UT) under 95% air/5% CO 2 at 37 °C, according to the protocol our lab published earlier (Chung et al ., 2006; Yuan et al ., 2010). …”

“…Lanosa et al found a close correlation between metabolic activation of styrene and the sensory irritation response to styrene (Lanosa et al ., 2010). Recently, our group reported cellular protein modification by styrene oxide in cultured micro-dissected mouse airways and cells after exposure to styrene (Yuan et al ., 2010). Mörbt et al also identified modified thioredoxin reductase by styrene oxide in cultured A297 cells incubated with styrene (Mörbt et al ., 2009).…”