Brevetoxin-induced DNA Damage in Respiratory Epithelial Cells
IAAAM 2009
Ayanna C. Phillips1; Barbara J. Sheppard1; Xingming Deng1
1University of Florida, College of Veterinary Medicine, Gainesville, FL, USA

Abstract

Effects of Brevetoxin-3 (PbTx-3) on excitatory tissues have been extensively studied, however, its cellular effects on epithelial linings following environmental exposure remain largely unknown. The respiratory epithelium of man and marine mammals is exposed to varying concentrations of aerosolized PbTx-3 during Karenia brevis blooms. Epithelial damage predisposes individuals to infectious secondary pathogenic invasion and thus additional morbidity and mortality. To investigate if PbTx-3 induces DNA damage and oxidative DNA lesions, in vitro studies were conducted using a 'normal' human bronchial epithelial cell line (BEAS-2B) as a model for marine mammal effects. Because symptoms of brevetoxin exposure are often worse in individuals with respiratory compromise, a neoplastic human respiratory epithelial cell line (H460) was also used as a model for respiratory compromise. A comet assay was used to determine if DNA damage occurs following exposure to 10, 100 and 500 ng/ml PbTx-3 for 1 hour at 37°C. Post-exposure, some cell loss was apparent at higher PbTx-3 concentrations. For BEAS-2B cells, the mean negative control tail moment was 6.05 (SE = ±1.14), the hydrogen peroxide-treated (H2O2) positive control was 53.98 (3.34), PbTx-3 at 10 ng/ml was 8.89 (0.82), at 100 ng/ml was 12.62 (1.42), and at 500 ng/ml was 6.81 (0.93). For H460 cells, the mean negative control tail moment was 0.30 (0.08), the positive control was 62.56 (14.14), PbTx-3 at 10 ng/ml was 11.16 (1.06), at 100 ng/ml was 0.13 (0.02), and at 500 ng/ml was 0.21 (0.05). The data indicates that exposure to PbTx-3 results in acute DNA damage in respiratory epithelial cells and may result in acute cell loss at higher concentrations. It also suggests that significant genotoxic damage can occur at lower PbTx-3 concentrations (10 ng/ml) in neoplastic respiratory epithelial cells, whereas higher concentrations (100 ng/ml) may be required to induce significant damage in uncompromised respiratory epithelial cells. A formamidopyrimidine-DNA glycosylase (Fpg) fragment length analysis using repair enzymes (FLARE) assay was used to determine if PbTx-3 induces oxidative DNA lesions following exposure for 20 minutes at 4°C. For Fpg-untreated BEAS-2B cells, the mean negative control tail moment was 4.37 (0.77), the H2O2-treated positive control was 8.55 (0.68), PbTx-3 at 10 ng/ml was 7.49 (0.70), at 100 ng/ml was 9.95 (0.74), and at 500 ng/ml was 9.32 (0.62). For Fpg-treated BEAS-2B cells, the mean negative control tail moment was 7.73 (0.80), the positive control was 9.79 (0.70), PbTx-3 at 10 ng/ml was 7.20 (0.73), at 100 ng/ml was 9.27 (0.76), and at 500 ng/ml was 9.17 (0.64). For Fpg-untreated H460 cells, the mean negative control tail moment was 6.48 (0.85), the positive control was 16.99 (0.64), PbTx-3 at 10 ng/ml was 2.69 (0.67), at 100 ng/ml was 4.08 (0.65), and at 500 ng/ml was 4.27 (0.67). For Fpg-treated H460 cells, the mean negative control tail moment was 3.45 (0.97), the positive control was 20.10 (0.73), PbTx-3 at 10 ng/ml was 3.41 (0.78), at 100 ng/ml was 3.20 (0.75), and at 500 ng/ml was 4.40 (0.77). FLARE data indicates that PbTx-3 exposure results in acute DNA damage in respiratory epithelial cells, and that significant oxidative lesions are induced at higher PbTx-3 concentrations (500 ng/ml) in neoplastic respiratory epithelial cells.

Speaker Information
(click the speaker's name to view other papers and abstracts submitted by this speaker)

Ayanna C. Phillips
University of Florida
College of Veterinary Medicine
Gainesville, FL, USA


MAIN : Therapeutics & Toxicology : Brevetoxin-Induced Damage
Powered By VIN

Friendly Reminder to Our Colleagues: Use of VIN content is limited to personal reference by VIN members. No portion of any VIN content may be copied or distributed without the expressed written permission of VIN.

Clinicians are reminded that you are ultimately responsible for the care of your patients. Any content that concerns treatment of your cases should be deemed recommendations by colleagues for you to consider in your case management decisions. Dosages should be confirmed prior to dispensing medications unfamiliar to you. To better understand the origins and logic behind these policies, and to discuss them with your colleagues, click here.

Images posted by VIN community members and displayed via VIN should not be considered of diagnostic quality and the ultimate interpretation of the images lies with the attending clinician. Suggestions, discussions and interpretation related to posted images are only that -- suggestions and recommendations which may be based upon less than diagnostic quality information.

CONTACT US

777 W. Covell Blvd., Davis, CA 95616

vingram@vin.com

PHONE

  • Toll Free: 800-700-4636
  • From UK: 01-45-222-6154
  • From anywhere: (1)-530-756-4881
  • From Australia: 02-6145-2357
SAID=27