Differential DNA damage response and cell fate in human lung cells after exposure to genotoxic compounds

DNA damage can impair normal cellular functions and result in various pathophysiological processes including cardiovascular diseases and cancer. We compared the genotoxic potential of diverse DNA damaging agents, and focused on their effects on the DNA damage response (DDR) and cell fate in human lung cells BEAS-2B. Polycyclic aromatic hydrocarbons [PAHs; benzo[a]pyrene (B[a]P), 1-nitropyrene (1-NP)] induced DNA strand breaks and oxidative damage to DNA; anticancer drugs doxorubicin (DOX) and 5-bromo-2'-deoxyuridine (BrdU) were less effective. DOX triggered the most robust p53 signaling indicating activation of DDR, followed by cell cycle arrest in the G2/M phase, induction of apoptosis and senescence, possibly due to the severe and irreparable DNA lesions. BrdU not only activated p53, but also increased the percentage of G1-phased cells and caused a massive accumulation of senescent cells. In contrast, regardless the activation of p53, both PAHs did not substantially affect the cell cycle distribution or senescence. Finally, a small fraction of cells accumulated only in the G2/M phase and exhibited increased cell death after the prolonged incubation with B[a]P. Overall, we characterized differential responses to diverse DNA damaging agents resulting in specific cell fate and highlighted the key role of DNA lesion type and the p53 signaling persistence.

The effect of tetrabromobisphenol A on protamine content and DNA integrity in mouse spermatozoa

Tetrabromobisphenol A (TBBPA) is a widely used brominated flame retardant of increasing concern to human health because of its action as an endocrine disruptor. We have previously demonstrated that TBBPA is able to increase apoptosis of testicular cells and other changes in the first and second generations of mice exposed to TBBPA. However, the potential effects of TBBPA on mouse epididymal spermatozoa have not yet been investigated. Therefore, we initiated this study to determine whether TBBPA exposure could also result in increased DNA fragmentation in epididymal spermatozoa and whether it had an effect on the protamines as the major nuclear proteins. C57Bl/6J mouse pups (n = 10) were exposed to TBBPA (experimental group) during the gestation, lactation, pre-pubertal and pubertal periods up to the age of 70 days as previously described and compared to control mouse pups (n = 10) that were not exposed. The results demonstrate that TBBPA treatment results in a significantly decreased protamine 1/protamine 2 ratio (0.362 vs. 0.494; p < 0.001), increased total protamine/DNA ratio (0.517 vs. 0.324; p < 0.001) and increased number of terminal deoxynucleotidyl transferase dUTP nick end labelling positive spermatozoa (39.5% vs. 21.2%; p < 0.05) observed between TBBPA and control mice respectively. These findings indicate that TBBPA exposure, in addition to the resulting increased sperm DNA damage, also has the potential to alter the epigenetic marking of sperm chromatin through generation of an anomalous content and distribution of protamines. The possibility is now open to study whether the detected altered protamine content and DNA integrity are related to the previously observed second-generation effects upon TBBPA exposure.

Monoclonal antibody FsC-47 against carp sperm creatine kinase

The enzyme creatine kinase (CK) plays a key role in energy homeostasis of cells with high and fluctuating energy requirements. As for spermatozoa, the activity of phosphocreatine shuttle, which directs energy from the mitochondria to sites of ATP consumption, is dependent on individual species. High activities of CK are observed in spermatozoa of nonvertebrate, fish, and birds, contrary to the low-level CK activity in mammalian spermatozoa. A new monoclonal antibody (MAb) to carp sperm creatine kinase was prepared. This antibody is applicable to large-scale immunochemical techniques. In this study, it was applied to the study of carp sperm motility, and the evaluation of the influence of CK on the quality and fertilization ability of carp spermatozoa.