The 3-methyl-4-nitrophenol (PNMC) compromises airway epithelial barrier function
TOXICOLOGY
Authors: An, Yun-Fang; Geng, Xiao-Rui; Mo, Li-Hua; Liu, Jiang-Qi; Yang, Li-Teng; Zhang, Xiao-Wen; Liu, Zhi-Gang; Zhao, Chang-Qing; Yang, Ping-Chang
Abstract
Background and aims: It is recognized that the air pollution is associated with the pathogenesis of airway diseases. This study aims to elucidate the role of the 3-methyl-4-nitrophenol (PNMC), one of the components of diesel-exhaust particles, in compromising the airway epithelial barrier integrity. Methods: A549 cells, an airway epithelial cell line, were cultured to monolayers to be used as an in vitro epithelial barrier model. BALB/c mice were treated with nasal drops containing PNMC to test the effects of PNMC on alternating the airway epithelial barrier functions. Results: Exposure of mice to PNMC induced nasal epithelial cell apoptosis and increased the permeability of the nasal epithelial barrier. PNMC increased casp8 and casp3 activities in nasal epithelial cells. Exposure to PNMC up regulated Fas and FasL expression in airway epithelial cells. Inhibition of caspase abolished the PNMC-induced airway epithelial barrier dysfunction. Conclusion: Exposure of airway mucosa to PNMC induces epithelial cell apoptosis and compromises the epithelial barrier function, which can be prevented by the inhibition of caspases.
Calcitriol combined with calcium chloride causes apoptosis in undifferentiated adipose tissue-derived human mesenchymal stem cells, but this effect decreases during adipogenic differentiation
BIOMEDICINE & PHARMACOTHERAPY
Authors: Pesarini, Joao Renato; Torres de Oliveira, Edwin Jose; Pessatto, Lucas Roberto; Maluf Rabacow, Ana Paula; Camassola, Melissa; dos Santos, Bruno Paiva; de Barros, Marcio Eduardo; Cantero, Wilson de Barros; Milan Brochado Antoniolli-Silva, Andreia Conceicao; Oliveira, Rodrigo Juliano
Abstract
Calcitriol, the bioactive hormone of vitamin D, is currently linked to several diseases, such as obesity and gain of adipose mass, due to its liposolubility and, consequently, its sequestration by adipocytes. As rates of obesity continue to increase, research on the biology of weight gain should be encouraged. This study evaluated the effects of calcitriol combined with CaCl2 on adipose tissue-derived human mesenchymal stem cells. We evaluated the cytotoxicity of the combination by MTT assays, in which undifferentiated cells and cells undergoing adipogenic differentiation were tested for 7 and 14 days. The results demonstrated that the combination of calcitriol at the IC50 and CaCl2 at the IC20 was effective at reducing the viability of mesenchymal stem cells, but with the progression of cell differentiation towards adipocytes, cell resistance to the cytotoxic effects increased. The percentages of dead cells were 88.29, 57.45 and 28.81% for undifferentiated cells and cells exposed to differentiation medium for 7 and 14 days, respectively. Undifferentiated cells were evaluated for apoptosis in response to the same combination using Annexin V assays, and a possible onset of programmed cell death in undifferentiated cells was detected. Additionally, the combination of the compounds altered the membrane permeability of undifferentiated cells by 16 percentage points and induced cell cycle arrest in S phase due to the accumulation of damage. An evaluation of gene expression revealed the overexpression of the GADD45 and ATM genes and the underexpression of the P21, P53, ATR, BCL-2, EIF2 AK3, IGF1R, DNAse-2, ATF, MAP3K4, ENGO-G, CASP3, CASP7 and CASP8 genes. Our results provide valuable insights into the biology of obesity and may contribute to the development of new anti-obesity therapies focusing on the inhibition of adipose tissue mesenchymal stem cell hyperplasia and adipogenic differentiation.