Effects of γ-hexachlorocyclohexane on apoptosis induced by serum deprivation in PC12 cells

The effects of γ-hexachlorocyclohexane, one of the endocrine disrupters, widely used for agricultural and medicinal purpose, on apoptosis in PC12 cells were investigated using western blotting analysis and reverse transcriptase-DNA polymerase chain reaction (RT-PCR) method. Apoptosis is a fundamental process necessary for development of individuals and organs. Although γ -HCH at high concentration did not have an effect on cell viability and apoptosis, DNA fragmentation was slightly enhanced, and apoptotic factors; Bax, Bad, cytochrome c and caspase-3 showed tendency to increase by the addition of a low dose of γ-HCH to the cell medium. However these changes were not statistically significant. It was concluded that γ -HCH did not affect on apoptosis in the PC12 cell line system, although γ -HCH has been reported to induce apoptosis in other cell lines

Effects of parabens on apoptosis induced by serum-free medium.

Alkyl esters of p-hydroxybenzoic acids (parabens), an endocrine disrupter, are used as preservatives in cosmetics and foods. In this study, to understand the relationship between parabens and differentiation in infants, the effects of parabens on apoptosis induced by serum deprivation in PC12 cells were investigated. In addition, apoptosis-related factors were assayed. As results, a tendency toward enhancement of apoptosis was observed in the cells cultured in the serum-free medium with methylparaben, and this tendency was suggested to be related to the contents of BAD, a pro-apoptotic protein. Butylparaben did not show any tendency to enhance apoptosis

Endogenous Purification of NR4A2 (Nurr1) Identified Poly(ADP-Ribose) Polymerase 1 as a Prime Coregulator in Human Adrenocortical H295R Cells

Aldosterone is synthesized in zona glomerulosa of adrenal cortex in response to angiotensin II. This stimulation transcriptionally induces expression of a series of steroidogenic genes such as HSD3B and CYP11B2 via NR4A (nuclear receptor subfamily 4 group A) nuclear receptors and ATF (activating transcription factor) family transcription factors. Nurr1 belongs to the NR4A family and is regarded as an orphan nuclear receptor. The physiological significance of Nurr1 in aldosterone production in adrenal cortex has been well studied. However, coregulators supporting the Nurr1 function still remain elusive. In this study, we performed RIME (rapid immunoprecipitation mass spectrometry of endogenous proteins), a recently developed endogenous coregulator purification method, in human adrenocortical H295R cells and identified PARP1 as one of the top Nurr1-interacting proteins. Nurr1-PARP1 interaction was verified by co-immunoprecipitation. In addition, both siRNA knockdown of PARP1 and treatment of AG14361, a specific PARP1 inhibitor suppressed the angiotensin II-mediated target gene induction in H295R cells. Furthermore, PARP1 inhibitor also suppressed the aldosterone secretion in response to the angiotensin II. Together, these results suggest PARP1 is a prime coregulator for Nurr1