Particle-induced expression of SF20/IL25 is mediated by reactive oxygen species and NF-κB in alveolar macrophages

Bronchoalveolar Lavage Fluid microRNA-146a: A Biomarker of Disease Severity and Pulmonary Function in Patients With Silicosis

OBJECTIVE

To examine the impact of microRNA-146a (miR-146a) on pulmonary function and disease severity in silicosis patients.

METHODS

Twenty-nine silicosis patients and six observation subjects were recruited. MiR-146a expression level was detected by qRT-PCR, and pulmonary function was assessed with a spirometer.

RESULTS

MiR-146a expression level was higher in silicosis patients than in observation subjects, and the probability of suffering from silicosis increased with increasing miR-146a level. MiR-146a was associated with the severity of silicosis. As the miR-146a increased, the probability of suffering from silicosis increased for stage I patients, and for stage II & III patients, the probability first increased and then decreased. MiR-146a was also associated with decreased pulmonary function measures, pulmonary function impairment, and restrictive ventilator dysfunction.

CONCLUSIONS

miR-146a was significantly associated with the disease severity and pulmonary function of silicosis.

Advances in carcinogenic metal toxicity and potential molecular markers

Metal compounds such as arsenic, cadmium, chromium, cobalt, lead, mercury, and nickel are classified as carcinogens affecting human health through occupational and environmental exposure. However, the underlying mechanisms involved in tumor formation are not well clarified. Interference of metal homeostasis may result in oxidative stress which represents an imbalance between production of free radicals and the system's ability to readily detoxify reactive intermediates. This event consequently causes DNA damage, lipid peroxidation, protein modification, and possibly symptomatic effects for various diseases including cancer. This review discusses predominant modes of action and numerous molecular markers. Attention is paid to metal-induced generation of free radicals, the phenomenon of oxidative stress, damage to DNA, lipid, and proteins, responsive signal transduction pathways with major roles in cell growth and development, and roles of antioxidant enzymatic and DNA repair systems. Interaction of non-enzymatic antioxidants (carotenoids, flavonoids, glutathione, selenium, vitamin C, vitamin E, and others) with cellular oxidative stress markers (catalase, glutathione peroxidase, and superoxide dismutase) as well as certain regulatory factors, including AP-1, NF-κB, Ref-1, and p53 is also reviewed. Dysregulation of protective pathways, including cellular antioxidant network against free radicals as well as DNA repair deficiency is related to oncogenic stimulation. These observations provide evidence that emerging oxidative stress-responsive regulatory factors and DNA repair proteins are putative predictive factors for tumor initiation and progression.