Mycotoxin adducts on human serum albumin: biomarkers of exposure to Stachybotrys chartarum.
OBJECTIVE
Despite the growing body of evidence showing adverse health effects from inhalation exposure to the trichothecene-producing mold Stachybotrys chartarum, controversy remains. Currently, there are no reliable assays suitable for clinical diagnosis of exposure. We hypothesized that satratoxin G (SG) -albumin adducts may serve as biomarkers of exposure to this fungus.


METHODS
We studied the formation of adducts of SG with serum albumin in vitro using Western blots and mass spectrometry (MS) and searched for similar adducts formed in vivo using human and animal serum.


RESULTS
Samples of purified human serum albumin that had been incubated with increasing concentrations of SG showed concentration-dependent albumin bands in Western blots developed with anti-SG antibodies. MS analysis found that as many as 10 toxin molecules can be bound in vitro to one albumin molecule. The sequencing of albumin-adduct tryptic peptides and the analysis of pronase/aminopeptidase digests demonstrated that lysyl, cysteinyl, and histidyl residues are involved in the formation of these adducts. Serum samples from three patients with documented exposure to S. chartarum similarly revealed lysine-, cysteine-, and histidine-SG adducts after exhaustive digestion, affinity column enrichment, and MS analysis. These adducts were also found in the sera from rats exposed to the spores of S. chartarum in contrast to control human subjects and control animals.


CONCLUSIONS
These data document the occurrence of SG-albumin adducts in both in vitro experiments and in vivo human and animal exposures to S. chartarum.


CONCLUSIONS
SG-amino acid adducts may serve as reliable dosimeter biomarkers for detection of exposure to S. chartarum.
Yike
Iwona
I
Department of Pediatrics and Mary Ann Swetland Center for Environmental Health, Case Western Reserve University, Cleveland, Ohio 44106-4948, USA.
Distler
Anne M
AM
Ziady
Assem G
AG
Dearborn
Dorr G
DG
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D015415:Biomarkers; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006868:Hydrolysis; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009183:Mycotoxins / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D012709:Serum Albumin / Q000737:chemistry*; D013172:Spores, Fungal; D013191:Stachybotrys / Q000737:chemistry*; D014255:Trichothecenes / Q000737:chemistry*; D014357:Trypsin
D000596:Amino Acids; D015415:Biomarkers; D009183:Mycotoxins; D010455:Peptides; D012709:Serum Albumin; D014255:Trichothecenes; C028268:satratoxin G; D014357:Trypsin