Young-Ah Han

A single intratracheal instillation of single-walled carbon nanotubes induced early lung fibrosis and subchronic tissue damage in mice

Large amounts of nanomaterials may reach both the natural and occupational environments. This represents a potential health hazard. People have forecasted that CNTs may lead to the toxicity such as mesothelioma and fibrosis like asbestos. To identify dominant immune responses induced by SWCNTs, we investigated the composition of bronchioalveolar lavage (BAL) cells, the secretion of cytokine and collagen, histopathology, protein expression, and cell phenotypes over time after a single administration of single-walled carbon nanotubes (SWCNT). In our results, the number of total cells and macrophages remained at the up-regulated level until Day 28, neutrophils rapidly increased at Day 1, and lymphocytes increased from Day 7. In the BAL fluid, pro-inflammatory cytokines rapidly increased at Day 1 and remained at an up-regulated level throughout the experimental period. IL-12 and IL-10 rapidly increased at Day 1 after administration and remained at a similar level until Day 28. IFN-γ and IL-4 reached the maximum at Day 1, and IL-5, TGF-β, and collagen reached the maximum at Day 7. IL-13 and IL-17 increased in a time-dependent manner. The distribution of B cells and cytotoxic T cells markedly increased at Days 7 and 14, and fibrotic lesions were histopathologically observed at Days 7 and 14. The expressions of caspase-3, p53, COL1A1, COX-2, iNOS, MMP-9, and MMP-2 were also markedly increased at Days 7 and 14. In addition, the expression of mesothelin, iNOS, MMP-9, and p53 was up-regulated until Day 28. Based on these findings, we suggest that a single intratracheal instillation of SWCNTs may induce early lung fibrosis and subchronic tissue damage.

Saururus chinensis Baill induces apoptosis through endoplasmic reticulum stress in HepG2 hepatocellular carcinoma cells

In this study, we examined the mechanism underlying the effect of Saururus chinensis Baill (saururaceae) on hepatocellular carcinoma HepG2 cells. HepG2 cells and Chang cells were exposed to various concentrations of S. chinensis Baill extract (SC-E) for 24 h. SC-E affected more significantly HepG2 cells than Chang cells in terms of cell viability and ATP production. Therefore, current study examined detailed mechanism how SC-E affected HepG2 cell survival. We found that SC-E (75 and 150 μg/ml) induced apoptosis via oxidative stress. SC-E also caused CCAAT-enhancer-binding protein homologous protein (CHOP) activation by dissociating the binding immunoglobulin protein (BiP) from inositol-requiring 1α (IRE1α) in the endoplasmic reticulum (ER) and induced Bax, cytochrome c release to cytosol, caspase-3 activation, and poly ADP ribose polymerase (PARP) cleavage, resulting in HepG2 cell apoptosis. Furthermore, SC-E caused ER Ca(2+) leakage into the cytosol; ER dilation and mitochondrial membrane damage were observed in transmission electron microscopy (TEM). Taken together, our results demonstrated that SC-E induced cancer cell apoptosis specifically through ER stress.