Mi-Hye Jeong

Potential autophagy enhancers protect against fipronil-induced apoptosis in SH-SY5Y cells

Oxidative stress created by environmental toxicants activates several signaling pathways. Autophagy is one of the first lines of defense against oxidative stress damage. The autophagy pathway can be induced and up-regulated in response to intracellular reactive oxygen species (ROS). Recently, we reported that fipronil (FPN)-induced mitochondria-dependent apoptosis is mediated through ROS in human neuroblastoma SH-SY5Y cells. In this study, we explored the role of autophagy to prevent FPN neurotoxicity. We investigated the modulation of FPN-induced apoptosis according to autophagy regulation. FPN activated caspase-9 and caspase-3, and induced nuclear fragmentation and condensation, all of which indicate that FPN-induced cell death was due to apoptosis. In addition, we observed FPN-induced autophagic cell death by monitoring the expression of LC3-II and Beclin-1. Exposure to FPN in SH-SY5Y cells led to the production of ROS. Treatment with N-acetyl-cysteine (NAC) effectively blocked both apoptosis and autophagy. Interestingly, pretreatment with rapamycin, an autophagy inducer, significantly enhanced the viability of FPN-exposed cells; the enhancement of cell viability was partially due to alleviation of FPN-induced apoptosis via a decrease in levels of cleaved caspase-3. However, pretreatment with 3-methyladenine (3MA) a specific inhibitor for autophagy, remarkably strengthened FPN toxicity and further induced activation of caspase-3 in these cells. Our studies suggest that FPN-induced cytotoxicity is modified by autophagy regulation and that rapamycin is neuroprotective against FPN-induced apoptosis through enhancing autophagy.

Meloxicam inhibits fipronil-induced apoptosis via modulation of the oxidative stress and inflammatory response in SH-SY5Y cells.

Oxidative stress and inflammatory responses have been identified as key elements of neuronal cell apoptosis. In this study, we investigated the mechanisms by which inflammatory responses contribute to apoptosis in human neuroblastoma SH‐SY5Y cells treated with fipronil (FPN). Based on the cytotoxic mechanism of FPN, we examined the neuroprotective effects of meloxicam against FPN‐induced neuronal cell death. Treatment of SH‐SY5Y cells with FPN induced apoptosis via activation of caspase‐9 and ‐3, leading to nuclear condensation. In addition, FPN induced oxidative stress and increased expression of cyclooxygenase‐2 (COX‐2) and tumor necrosis factor‐α (TNF‐α) via inflammatory stimulation. Pretreatment of cells with meloxicam enhanced the viability of FPN‐exposed cells through attenuation of oxidative stress and inflammatory response. FPN activated mitogen activated protein kinase (MAPK) and inhibitors of MAPK abolished FPN‐induced COX‐2 expression. Meloxicam also attenuated FPN‐induced cell death by reducing MAPK‐mediated pro‐inflammatory factors. Furthermore, we observed both nuclear accumulation of p53 and enhanced levels of cytosolic p53 in a concentration‐dependent manner after FPN treatment. Pretreatment of cells with meloxicam blocked the translocation of p53 from the cytosol to the nucleus. Together, these data suggest that meloxicam may exert anti‐apoptotic effects against FPN‐induced cytotoxicity by both attenuating oxidative stress and inhibiting the inflammatory cascade via inactivation of MAPK and p53 signaling. Copyright

Pulmonary Proteome and Protein Networks in Response to the Herbicide Paraquat in Rats.

Paraquat (PQ) has been one of the most widely used herbicides in the world. PQ, when ingested, is toxic to humans and may cause acute respiratory distress syndrome. To investigate molecular perturbation in lung tissues caused by PQ, Sprague Dawley male rats were fed with PQ at a dose of 25 mg/kg body weight for 20 times in four weeks. The effects of PQ on cellular processes and biological pathways were investigated by analyzing proteome in the lung tissues in comparison with the control. Among the detected proteins, 321 and 254 proteins were over-represented and under-represented, respectively, in the PQ-exposed rat lung tissues in comparison with the no PQ control. All over- and under-represented proteins were subjected to Ingenuity Pathway Analysis to create 25 biological networks and 38 pathways of interacting protein clusters. Over-represented proteins were involved in the C-jun-amino-terminal kinase pathway, caveolae-mediated endocytosis signaling, cardiovascular-cancer-respiratory pathway, regulation of clathrin-mediated endocytosis, non-small cell lung cancer signaling, pulmonary hypertension, glutamate receptor, immune response and angiogenesis. Under-represented proteins occurred in the p53 signaling pathway, mitogen-activated protein kinase signaling pathway, cartilage development and angiogenesis inhibition in the PQ-treated lungs. The results suggest that PQ may generate reactive oxygen species, impair the MAPK/p53 signaling pathway, activate angiogenesis and depress apoptosis in the lungs.

Comparison of International Guidelines of Dermal Absorption Tests Used in Pesticides Exposure Assessment for Operators

The number of farmers who have suffered from non-fatal acute pesticide poisoning has been reported to vary from 5.7% to 86.7% in South Korea since 1975. Absorption through the skin is the main route of exposure to pesticides for farmers who operate with them. Several in vitro tests using the skins of humans or animal and in vivo tests using laboratory animals are introduced for the assessment of human dermal absorption level of pesticides. The objective of this study is to evaluate and compare international guidelines and strategies of dermal absorption assessments and to propose unique approaches for applications into pesticide registration process in our situation. Until present in our situation, pesticide exposure level to operator is determined just using default value of 10 as for skin absorption ratio because of data shortage. Dermal absorption tests are requested to get exposure level of pesticides and to ultimately know the safety of pesticides for operators through the comparison with the value of AOEL. When the exposure level is higher than AOEL, the pesticide cannot be approved. We reviewed the skin absorption test guidelines recommended by OECD, EFSA and EPA. The EPA recommends assessment of skin absorption of pesticides for humans through the TPA which includes all the results of in vitro human and animal and animal in vivo skin absorption studies. OECD and EFSA, employ a tiered approach, which the requirement of further study depends on the results of the former stage study. OECD guidelines accept the analysis of pesticide level absorbed through skin without radioisotope when the recovery using the non-labeled method is within 80~120%. Various factors are reviewed in this study, including the origin of skin (gender, animal species and sites of skin), thickness, temperature and, etc., which can influence the integrity of results.

Comparison Assessment for Acute Oral and Dermal Toxicity of Plant Protection Products and Active Ingredients

농약 독성 구분과 표시를 위해 농약관리법에서는 급성경구독성과 급성경피독성 시험성적을 제출하도록 하고 있다. 본 연구에서는 급성경구독성 자료로 급성경피독성을 예측하고 급성독성을 평가할 수 있는지 알아보고자 511개 제품과 72개 원제의 급성경구독성, 급성경피독성을 비교·분석하였다. 농약관리법 기준을 적용 시 급성경구독성과 급성경피독성 등급이 제품의 78%가 동일하였고, GHS 분류체계 적용 시에는 77.9%가 동일하였다. 급성경구독성이 경피독성보다 더 강한 경우는 농약관리법 분류체계, GHS 분류체계 적용 시 각각 13.5%, 21.9%으로, 제품의 91.5%, 99.7%가 급성경구독성으로 제품의 독성 등급이 구분되었다. 원제의 경우, 위험성·유해성 분류에 따른 표시기준에 준하여 독성을 분류하였다. 급성경구독성, 급성경피독성 시험의 각 LD50을 이용하여 독성을 분류하였을 때 대상 원제 100%가 급성경구독성이 급성경피독성 등급과 같거나 독성이 더 강하게 분류되었다. 하지만 급성경피독성자료 없이 급성경구독성의 LD50로만 급성경피독성 기준에 따라 경피독성 등급을 구분하였을 때, 급성경피독성 LD50 자료를 이용했을 때보다 원제의 21.4%에서 독성이 더 강하게 구분되었다. 이를 통해 급성경피 독성자료가 농약 독성평가에 추가적인 정보를 거의 제공하지 않는다는 것을 알 수 있었다.

DNA Damage Effect of Botanical Insecticides Using Chinese Hamster Lung Cells

BACKGROUND: Botanical insecticides, especially Azadirachta Indica extract (AIE) and Sophorae radix extract (SRE) are widely used in Agriculture field. In our previous studies on genotoxicity test of AIE and SRE samples, a suspicious clastogenic properties was shown. Herein, we investigated the DNA damage effect of these botanical insecticide samples through the in vitro comet assay. METHODS AND RESULTS: Chinese hamster lung (CHL) fibroblast cell line was used, and methyl methanesulphonate was as positive control. Respective two samples of AIE and SRE were evaluated using Single Cell Gel Electrophoresis (Comet) assay and measured as the Olive tail moment (OTM). Results from this study indicated that all tested AIE and SRE samples did not show DNA damage in comet assay using CHL cells, compared with control. CONCLUSION: AIE and SRE samples used in this study were not cause genetic toxicity and are suitable for use as organic materials.

Health status and related factors in farmers by SF-12

ObjectivesThis study was performed to understand farmers’ health status by general characteristic, and to find out the related factors.MethodsAll the 984 subjects were interviewed by means of a structured questionnaire and SF-12. Among them, only 812 were eligible for analysis. Statistical methods used included frequency, t-test, ANOVA, binary logistic regression with SPSS 19.0.ResultsIn binary logistic regression, marital status, smoking, regular exercise and monthly day off were associated with physical component score. Marital status, smoking and score of pesticide protective device wearing were associated with mental component score.ConclusionsThis study suggests that effort to develop health promotion programs for workers of agricultural industry considering these results can improve their perceived health status.

Anti-diabetic Effects of Isaria tenuipes in OLETF Rats as an Animal Model of Diabetes Mellitus Type II

ABSTRACT - We evaluated the anti-diabetic effects of Isaria tenuipes in diabetes mellitus type 2. For the exper-iments, the diabetic animal model OLETF rats were divided to 4 groups: Isaria tenuipes was administered mixed withthe high fat diet 45% at dose levels of 0.0%, 0.1%, 1.0%, and 5.0% for 4 weeks. All animals have free access to waterand high fat diet 45%. The diabetic clinical markers, including clinical signs, body weight and food intake, organweights, blood glucose level, insulin level and HOMA-IR index, oral glucose tolerance test, GLUT4 mRNA and pro-tein were measured at a time. After administration for 4 weeks, the blood glucose levels, insulin levels and HOMA-IR index of test groups were decreased compared with control group in dose-dependent manner. The body weight anddiet consumptions were reduced in control group at 4 weeks. The treatments of Isaria tenuipes also showed highexpression of GLUT4 mRNA and protein in the muscle of OLETF rats. The results suggest that Isaria tenuipes hasanti-hyperglycemic effect attenuating blood glucose in the animal model of type 2 diabetes and might be useful as afunctional diet for human diabetic diseases.Key words: Isaria tenuipes, diabetes mellitus, OLETF rats, glucose, insulin, GLUT4