Synthesis of phenanthridine spiropyrans and studies of their effects on G-quadruplex DNA.

G-quadruplex (G4) DNA structures are involved in many important biological processes and can be linked to several human diseases. Drug-like low molecular weight compounds that target G4 structures are therefore interesting not only for their potential therapeutic properties but also for their potential use as chemical research tools. We report here on the development of methods to synthesize spiropyrans using a condensation-cyclisation reaction of quaternary salts of α-methyl quinoline or phenanthridine with salicylaldehydes. Evaluation of the synthesized phenanthridine spiropyrans' interactions with G4 DNA was performed with a Thioflavin T displacement assay, circular dichroism, Taq DNA polymerase stop assay, and NMR. This revealed that the substitution pattern on the phenanthridine spiropyrans was very important for their ability to bind and stabilize G4 structures. Some of the synthesized low molecular weight spirocyclic compounds efficiently stabilized G4 structures without inducing structural changes by binding the first G-tetrad in the G4 structure.

Glucocorticoid receptor gene expression in adipose tissue and associated metabolic risk in black and white South African women.

BACKGROUND: Black women have lower visceral adipose tissue (VAT) but are less insulin sensitive than white women; the mechanisms responsible are unknown. OBJECTIVE: The study aimed to test the hypothesis that variation in subcutaneous adipose tissue (SAT) sensitivity to glucocorticoids might underlie these differences. METHODS: Body fatness (dual energy X-ray absorptiometry) and distribution (computerized tomography), insulin sensitivity (SI, intravenous and oral glucose tolerance tests), and expression of 11ß-hydroxysteroid dehydrogenase-1 (11HSD1), hexose-6-phosphate dehydrogenase and glucocorticoid receptor-α (GRα), as well as genes involved in adipogenesis and inflammation were measured in abdominal deep SAT, superficial SAT and gluteal SAT (GLUT) depots of 56 normal-weight or obese black and white premenopausal South African (SA) women. We used a combination of univariate and multivariate statistics to evaluate ethnic-specific patterns in adipose gene expression and related body composition and insulin sensitivity measures. RESULTS: Although 11HSD1 activity and mRNA did not differ by ethnicity, GRα mRNA levels were significantly lower in SAT of black compared with white women, particularly in the GLUT depot (0.52±0.21 vs 0.91±0.26 AU, respectively, P<0.01). In black women, lower SAT GRα mRNA levels were associated with increased inflammatory gene transcript levels and abdominal SAT area, and reduced adipogenic gene transcript levels, VAT/SAT ratio and SI. Abdominal SAT 11HSD1 activity associated with increased VAT area and decreased SI in white, but not in black women. CONCLUSIONS: In black SA women, downregulation of GRα mRNA levels with obesity and reduced insulin sensitivity, possibly via increased SAT inflammation, is associated with reduced VAT accumulation.