Asynchronous Rhythm of Steroidogenic Factor 1 and Period Homolog 2 mRNA Expression in Mouse Y1 Adrenocorticol Tumor Cells

The relationship between the expression of Steroidogenic factor 1 (Sf1) and the circadian-related gene, period homolog 2 (Per2), in the adrenal cortex is still unknown. We show here that in Y1 adrenocortical tumor cells, expression of steroidogenic-related genes such as P450scc mRNA and Sf1 mRNA were asynchronous with Per2 mRNA. SF1 promoter analyses showed that the E-box element functions in a rhythmic pattern. Rhythmic expression of Upstream factor 1 mRNA, correlated well with Sf1 mRNA expression. We propose that tumorigenesis of adrenocortical lesions cause disruption of synchronous expression of steroidogenic-related and circadian-related genes

Expression of prostacyclin-stimulating factor (PSF) in mononuclear cells of human peripheral blood and THP-1 derived macrophage-like cells, and effects of high glucose concentration

Prostacyclin (PGI2) synthesis by vascular endothelial cells (ECs) decreases in diabetic subjects, possibly leading to development of diabetic angiopathies including that in atherosclerosis. We identified a bioactive peptide, prostacyclin-stimulating factor (PSF), which stimulates PGI2 synthesis in cultured aortic ECs. Our previous studies demonstrated that PSF was predominantly expressed by arterial smooth muscle cells (SMCs) and ECs. We immunohistochemically showed that PSF existed in SMCs of human coronary arteries, and PSF staining was markedly reduced in coronary arterial SMCs of patients with type 2 diabetes and/or myocardial infarction. In the present study, we investigated the existence of PSF in human serum, and effects of glucose on serum PSF levels in patients with type 2 diabetes. Immunoblot analysis revealed the presence of PSF in serum, and showed that serum PSF protein concentration was significantly decreased in type 2 diabetic patients. Moreover, there was a significant negative correlation between serum PSF and HbA1c levels in these patients. Using immunohistochemistry, we also showed that PSF was present in serum and in macrophages (Mfs). PSF mRNA was found in Mfs using reverse transcription-polymerase chain reaction (RT-PCR). In addition, effects of high glucose conditions on PSF production in Mfs were examined by Western blotting, and we showed that PSF significantly decreased when Mfs were cultured in high glucose conditions. These results strongly suggested that decreased PSF production might result in decreased production of PGI_2 in atherosclerotic lesions, thus leading to development of diabetic macroangiopathy and atherosclerosis

Atrazine-Induced Aromatase Expression Is SF-1 Dependent: Implications for Endocrine Disruption in Wildlife and Reproductive Cancers in Humans

BACKGROUND: Atrazine is a potent endocrine disruptor that increases aromatase expression in some human cancer cell lines. The mechanism involves the inhibition of phosphodiesterase and subsequent elevation of cAMP. METHODS: We compared steroidogenic factor 1 (SF-1) expression in atrazine responsive and non-responsive cell lines and transfected SF-1 into nonresponsive cell lines to assess SF-1’s role in atrazine-induced aromatase. We used a luciferase reporter driven by the SF-1–dependent aromatase promoter (ArPII) to examine activation of this promoter by atrazine and the related simazine. We mutated the SF-1 binding site to confirm the role of SF-1. We also examined effects of 55 other chemicals. Finally, we examined the ability of atrazine and simazine to bind to SF-1 and enhance SF-1 binding to ArPII. RESULTS: Atrazine-responsive adrenal carcinoma cells (H295R) expressed 54 times more SF-1 than nonresponsive ovarian granulosa KGN cells. Exogenous SF-1 conveyed atrazine-responsiveness to otherwise nonresponsive KGN and NIH/3T3 cells. Atrazine induced binding of SF-1 to chromatin and mutation of the SF-1 binding site in ArPII eliminated SF-1 binding and atrazine-responsiveness in H295R cells. Out of 55 chemicals examined, only atrazine, simazine, and benzopyrene induced luciferase via ArPII. Atrazine bound directly to SF-1, showing that atrazine is a ligand for this “orphan” receptor. CONCLUSION: The current findings are consistent with atrazine’s endocrine-disrupting effects in fish, amphibians, and reptiles; the induction of mammary and prostate cancer in laboratory rodents; and correlations between atrazine and similar reproductive cancers in humans. This study highlights the importance of atrazine as a risk factor in endocrine disruption in wildlife and reproductive cancers in laboratory rodents and humans

Correlation between 21st Century COE of Center for Frontier Research Education on Lifestyle-Related Disease based on the Large-scale Cohort Study and Kyushu University hospital

九州大学病院統合1周年記念企

21世紀COEと病院の関係

九州大学病院統合1周年記念企

Nuclear Compartmentalization of N-CoR and Its Interactions with Steroid Receptors

The repression mechanisms by the nuclear receptor corepressor (N-CoR) of steroid hormone receptor (SHR)-mediated transactivation were examined. Yellow fluorescent protein (YFP)-N-CoR was distributed as intranuclear discrete dots, while coexpression of androgen receptor (AR), glucocorticoid receptor α, and estrogen receptor α ligand-dependently triggered redistribution of YFP-N-CoR. In fluorescence recovery after photobleaching analysis, mobility of the N-CoR was reduced by 5α-dihydrotestosterone (DHT)-bound AR. The middle region of N-CoR mostly contributed to the interaction with agonist-bound SHRs and the suppression of their transactivation function. N-CoR impaired the DHT-induced N-C interaction of AR, and the impaired interaction was dose-dependently recovered by coexpression of SRC-1 and CBP. N-CoR also impaired the intranuclear complete (distinct) focus formation of SHRs. Coexpression of SRC-1 or CBP released YFP-N-CoR or endogenous N-CoR from incomplete foci and simultaneously recovered complete foci of AR-green fluorescent protein. These results indicate that the relative ratio of coactivators and corepressors determines the conformational equilibrium between transcriptionally active and inactive SHRs in the presence of agonists. The intranuclear foci formed by agonist-bound SHRs were completely destroyed by actinomycin D and α-amanitin, indicating that the focus formation does not precede the transcriptional activation. The focus formation may reflect the accumulation of SHR/coactivator complexes released from the transcriptionally active sites and thus be a mirror of transcriptionally active complex formation