[Effects of Cadmium on Ca2+ and IRE1 signaling pathway in GC2 spd cells].

OBJECTIVE: To study the effects of cadmium on autophagy in germ cells (GC-2 spd cells) through Ca2+ and IRE1 pathway. METHODS: The viability of GC-2 spd cells was determined using a CCK-8 assay to establish the concentration of cadmium treating . MDC staining was employed to assess autophagosome formation. Laser confocal microscopy and flow cytometry were utilized to measure cytoplasmic and endoplasmic reticulum (ER) Ca2+ levels. Western blot was conducted to evaluate the expression levels of proteins associated with the IRE1 signaling pathway and autophagy. RESULTS: As the concentration of cadmium increased, cell viability gradually decreased. The concentrations of cadmium were determined to be 2.5, 5, and 10 µmol/L. Compared with the control group, the IOD values of MDC fluorescence intensity within the cadmium group were all elevated (P<0.05), accompanied by elevated ratios of autophagy markers LC3-II/LC3-I and up-regulation of Beclin-1 protein expression (P<0.05). Cytoplasm Ca2+ levels gradually increased, while ER Ca2+ levels decreased (P<0.05). The expression of IP3R protein, the ER Ca2+ release pathway, was up-regulated (P<0.05). Additionally, the expressions of IRE1, XBP1s, CHOP, and GRP78 were up-regulated in the cadmium group (P<0.05). CONCLUSION: Cadmium exposure can induce dysregulation of calcium homeostasis in GC-2spd cells, activates the ER stress-induced IRE1 signaling pathway, and ultimately induces the occurrence of autophagy in GC-2spd cells.

Characterization and Expression Analysis of Peroxiredoxin Genes in NNK-induced V79 Cells.

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent and prevalent nitrosamine procarcinogen found in cigarette smoke. The aim of this work is to study alterations in peroxiredoxin (Prx) expression induced by NNK during carcinogenesis. Characterization of Prx genes from hamster was performed using bioinformatics. V79 cells were induced with different concentrations of NNK (0.1-0.4 mg/mL), and the expression levels of six Prx genes (Prx1-Prx6) were measured by qRT-PCR 24 h following NNK treatment. Prx gene expression was induced by NNK stress, and the highest transcription levels were induced by over 20.42-fold relative to that of the control. NNK induced alterations in Prx expression over the course of lung cancer, which means Prxs may play important roles in ROS detoxification under NNK stress and their functions are complementary.

Decreased birth weight in relation to maternal urinary trichloroacetic acid levels.

BACKGROUND: The effect of exposure to disinfection by-products (DBPs) during pregnancy on newborn's birth weight has been commonly described in animal studies. However, epidemiological evidence was not consistent. OBJECTIVES: To investigate the relationship between exposure to DBPs and newborn's birth weight in a Chinese population, we conducted a cross-sectional study in Wuhan, China. METHODS: A total number of 398 women who had given birth to a live singleton with a gestational age between 37 to 42 weeks were recruited from a local hospital between November 2008 and May 2009. Basic information for all mothers and newborns was obtained from clinic birth records. Among these subjects, 180 women also gave further information including maternal medical history, social status and water-use behaviors by a face-to-face interview. Urinary creatinine (Cr) adjusted trichloroacetic (TCAA) was used as an exposure biomarker. RESULTS: No statically significant results were found in the linear regression for both 398 participants and 180 participants who finished questionnaires. However, both the crude and adjusted results showed that the mean birth weight of the subjects in the third and top quartiles of Cr-adjusted urinary TCAA concentrations was decreased compared with those in the lowest quartile. Subjects in the top quartiles had the lowest mean birth weight compared to those in other quartiles. In addition, a weak correlation was observed among 82 subjects between drinking water ingestion and urinary Cr-adjusted TCAA (r=0.23, P=0.04). CONCLUSION: Our findings suggested that elevated exposure to DBPs may affect fetal growth. The effect of exposure to DBPs during pregnancy on birth weight still warrants further investigations.