Project description:The reactivity of RNA 2'-OH groups with acylating agents has recently been investigated for high-yield conjugation of RNA strands. To date, only achiral molecules have been studied for this reaction, despite the complex chiral structure of RNA. Here we prepare a set of chiral acylimidazoles and study their stereoselectivity in RNA reactions. Reactions performed with unfolded and folded RNAs reveal that positional selectivity and reactivity vary widely with local RNA macro-chirality. We further document remarkable effects of chirality on reagent reactivity, identifying an asymmetric reagent with 1000-fold greater reactivity than prior achiral reagents. In addition, we identify a chiral compound with higher RNA structural selectivity than any previously reported RNA-mapping species. Further, azide-containing homologs of a chiral dimethylalanine reagent were synthesized and applied to local RNA labeling, displaying 92% yield and 16:1 diastereoselectivity. The results establish that reagent stereochemistry and chiral RNA structure are critical elements of small molecule-RNA reactions, and demonstrate new chemical strategies for selective RNA modification and probing.
Project description:Polybrominated diphenyl ethers (PBDEs) are commonly used as flame retardants in a variety of commercial and household products. They have been detected in the environment and accumulate in mammalian tissues and fluids. PBDE toxicity is thought to be associated with endocrine disruption, developmental neurotoxicity and changes in fetal development. Although humans are exposed to PBDEs, our knowledge of the effects of PBDE metabolites on human cells with respect to health risk is insufficient. Two hydroxylated PBDEs (OH-PBDEs), 2-OH-BDE47 and 2-OH-BDE85, were investigated for their effects on cell viability/proliferation, DNA damage, cell cycle distribution and gene expression profiling in H295R adrenocortical carcinoma cells. We show that the two agents are cytotoxic in a dose-dependent manner only at micromolar concentrations, with 2-OH-BDE85 being more toxic than 2-OH-BDE47. However, no DNA damage was observed for either chemical, suggesting that the biological effects of OH-PBDEs occur primarily via non-genotoxic routes. Furthermore, no evidence of aryl hydrocarbon receptor (AHR)-mediated, dioxin-like toxicity was observed. Instead, we report that a micromolar concentration of OH-PBDEs induces transcriptional changes associated with endoplasmic reticulum stress and the unfolded protein response. We discuss whether OH-PBDE bioaccumulation could result in impairment of the adrenocortical secretory function.
Project description:Vitamin D is a pro-hormone that possesses various anticancer effects through diverse mechanisms. The enzyme vitamin D-25-hydroxylase can convert vitamin D into 25-hydroxyvitamin D (25(OH)D) in the liver. 25(OH)D serves as the precursor of 1,25-dihydroxyvitamin D (1,25(OH)2D or calcitriol), which can be transformed into 1,25(OH)2D by the enzyme CYP27B1. CYP27B1 is primarily distributed in the kidneys but can also be found in other tissues, such as the breast and colon. Although 1,25-dihydroxyvitamin D has been the primary object of in vitro studies, emerging evidence suggests that 25(OH)D can also generate anticancer effects by transforming into 1,25(OH)2D in the manner of autocrine and paracrine. Our study aims to investigate the impact of 25(OH)D on breast cancer and its effect on the expression of small RNA in breast cancer cells cultured with 100nM 25(OH)D.
Project description:gene expression profiling by RNA-seq in THP-1 cells treated with 1,25(OH)2D3 for 2.5-24 h three independent experiments of 1,25(OH)2D3 time course in THP-1 cells
Project description:Neonatal keratinocytes from African American donors of passage 2 or 3 were treated with 20,23(OH)2D3, 1,25(OH)2D3 or 0.1% ethanol (control) for 6 and 24 hours. The cells were harvested separately, RNA isolated and submitted for microarray analysis at the Molecular Resources Center at the UTHSC.
Project description:Fibroblast growth factor 23 (FGF23) is produced and secreted by osteocytes and is essential for maintaining phosphate homeostasis. One of the main regulators of FGF23, 1,25-dihydroxyvitamin D (1,25(OH)2D3), is primarily synthesized in the kidney from 25-hydroxyvitamin D (25(OH)D) by 1α-hydroxylase (encoded by CYP27B1). Hitherto, it is unclear whether osteocytes can convert 25(OH)D and thereby allow for 1,25(OH)2D3 to induce FGF23 production and secretion locally. Here, we differentiated MC3T3-E1 cells towards osteocyte-like cells expressing and secreting FGF23. Treatment with 10-6 M 25(OH)D resulted in conversion of 25(OH)D to 150 pmol/L 1,25(OH)2D3 and increased FGF23 expression and secretion but the converted amount of 1,25(OH)2D3 was insufficient to trigger an FGF23 response, so the effect on FGF23 was most likely directly caused by 25(OH)D. Interestingly, combining phosphate with 25(OH)D resulted in a synergistic increase in FGF23 expression and secretion, likely due to activation of additional signaling pathways by phosphate. Blockage of the vitamin D receptor (VDR) only partially abolished the effects of 25(OH)D or 25(OH)D combined with phosphate on Fgf23, while completely inhibiting the upregulation of cytochrome P450 family 24 subfamily A member 1 (Cyp24a1), encoding for 24-hydroxylase. RNA sequencing and in silico analyses showed that this could potentially be mediated by the nuclear receptors Retinoic Acid Receptor b (RARB) and Estrogen Receptor 2 (ESR2). Taken together, we demonstrate that osteocytes are able to convert 25(OH)D to 1,25(OH)2D3, but this is insufficient for FGF23 activation, implicating a direct effect of 25(OH)D in the regulation of FGF23, which occurs at least partially independent from its cognate vitamin D receptor Moreover, phosphate and 25(OH)D synergistically increase expression and secretion of FGF23, which warrants investigating consequences in patients receiving a combination of vitamin D analogues and phosphate supplements. These observations help us to further understand the complex relations between, phosphate, vitamin D and FGF23.
Project description:Assessment of regions of open chromatin by FAIRE-seq in THP-1 cells treated with 1,25(OH)2D3 for 0-48 h Three independent experiments of 1,25(OH)2D3 time course in THP-1 cells
Project description:Purpose: The goal of this study was to perform an expression transcript profile over a timecourse of human preadipocytes that were treated with PCB52 or 4-OH-PCB52; Methods: Immortal human preadipocytes (NPAD) were treated with 10 uM PCB52 or 4-OH-PCB52 in PGM2 media containing 10%FBS for 9 hrs, 1 day, or 3 days. RNA was extracted with TriZol, DNase treated, and purified using a Qiagen column. RNAseq was used to assess gene expression. Bioinformatic analyses were used to determine differential gene expression between PCB52 or 4-OH-PCB52 treated and vehicle-treated at the same timepoint.
Project description:Monocytes, derived from three different donors, were stimulated with the vaccine adjuvant Al(OH)3 for 24 and 48 hours. Proteins were isolated and equal protein amounts were labeledusing TMT(6). We found that Al(OH)3 activates various pathways related to the innate immune response.