Epidemiological and pre-clinical studies support the anti-tumor effects of ω-3 PUFAs; however, the results from human trials are mixed, making it difficult to provide dietary guidelines or recommendations of ω-3 PUFAs for disease prevention or treatment. Understanding the molecular mechanisms by which ω-3 PUFAs inhibit cancer could lead to better nutritional paradigms and human trials to clarify their health effects. The ω-3 PUFAs exert their biological activities mainly through the formation of bioactive lipid metabolites. Here we discuss the biology of cyclooxygenase, lipoxygenase and cytochrome P450 enzymes-derived ω-3-series lipid metabolites on angiogenesis, inflammation and cancer.

Strands of DNA with four or more contiguous runs of 2'-deoxycytidine (dC) nucleotides have the potential to adopt i-motif folds, generally under mildly acidic conditions. Analysis of dC homo-oligonucleotide strands ranging in length from 10 to 30 nucleotides by five different pH-dependent methods identified a pattern in strand length vs stability. Beginning with dC, which does not fold, the transition pH (pH) increased with chain length with the addition of up to four nucleotides, after which the stability dramatically decreased, and the trend repeated this cycle up to dC. The analysis found dC strands of length 15, 19, 23, and 27 nucleotides (i.e., 4n-1) to have pH values >7.2 and thermal stabilities >37 °C at pH 7.0. Model studies using thymidine nucleotides to lock in i-motif loop lengths support the conclusion that the most stable dC i-motifs possess one nucleotide in each of the three loops and a core built of an even number of base pairs. The pattern identified from the model studies occurs with a frequency of four nucleotides at lengths of 15, 19, 23, and 27 in accordance with the results obtained for the dC strands. This observation led us to interrogate the human genome for dC runs. Inspection of the human genome indicates that dC runs are enriched in critical regions of the genome (promoters, UTRs, and introns), while being depleted in coding and intergenic regions, and these findings may have biological implications. Lastly, the ability to tune i-motif stabilities by the length of the strand might be harnessed for stimulus-responsive applications in DNA scaffolds, sensors, nanotechnology, and other chemical applications.

The cellular response to oxidative stress includes transcriptional changes, particularly for genes involved in DNA repair. Recently, our laboratory demonstrated that oxidation of 2'-deoxyguanosine (G) to 8-oxo-7,8-dihydro-2'-deoxyguanosine (OG) in G-rich potential G-quadruplex sequences (PQSs) in gene promoters impacts the level of gene expression up or down depending on the position of the PQS in the promoter. In the present report, bioinformatic analysis found that the 390 human DNA repair genes in the genome ontology initiative harbor 2936 PQSs in their promoters and 5'-untranslated regions (5'-UTRs). The average density of PQSs in human DNA repair genes was found to be nearly 2-fold greater than the average density of PQSs in all coding and noncoding human genes (7.5 vs 4.3 per gene). The distribution of the PQSs in the DNA repair genes on the nontranscribed (coding) vs transcribed strands reflects that of PQSs in all human genes. Next, literature data were interrogated to select 30 PQSs to catalog their ability to adopt G-quadruplex (G4) folds in vitro using five different experimental tests. The G4 characterization experiments concluded that 26 of the 30 sequences could adopt G4 topologies in solution. Last, four PQSs were synthesized into the promoter of a luciferase plasmid and cotransfected with the G4-specific ligands pyridostatin, Phen-DC3, or BRACO-19 in human cells to determine whether the PQSs could adopt G4 folds. The cell studies identified changes in luciferase expression when the G4 ligands were present, and the magnitude of the expression changes dependent on the PQS and the coding vs template strand on which the sequence resided. Our studies demonstrate PQSs exist at a high density in human DNA repair gene promoters and a subset of the identified sequences may fold in vitro and in vivo.

The Irish national registry for inherited retinal degenerations (Target 5000) is a clinical and scientific program to identify individuals in Ireland with inherited retinal disorders and to attempt to ascertain the genetic cause underlying the disease pathology. Potential participants first undergo a clinical assessment, which includes clinical history and analysis with multimodal retinal imaging, electrophysiology, and visual field testing. If suitable for recruitment, a sample is taken and used for genetic analysis. Genetic analysis is conducted by use of a retinal gene panel target capture sequencing approach. With over 1000 participants from 710 pedigrees now screened, there is a positive candidate variant detection rate of approximately 70% (495/710). Where an autosomal recessive inheritance pattern is observed, an additional 9% (64/710) of probands have tested positive for a single candidate variant. Many novel variants have also been detected as part of this endeavor. The target capture approach is an economic and effective means of screening patients with inherited retinal disorders. Despite the advances in sequencing technology and the ever-decreasing associated processing costs, target capture remains an attractive option as the data produced is easily processed, analyzed, and stored compared to more comprehensive methods. However, with decreasing costs of whole genome and whole exome sequencing, the focus will likely move towards these methods for more comprehensive data generation.

Scope Substantial studies have shown that curcumin, a dietary compound from turmeric, has beneficial effects on many diseases. However, curcumin rapidly degrades at physiological pH, making it difficult to interpret whether the observed actions of curcumin are from curcumin itself or its degradation products. Therefore, it is important to better understand the mechanisms involved in curcumin degradation and the roles of degradation in its biological actions. Methods and results Here, we show that a series of redox active antioxidants with diverse chemical structures, including gallic acid, ascorbate (vitamin C), tert‐butylhydroquinone (TBHQ), caffeic acid, rosmarinic acid, and Trolox (a water‐soluble analog of vitamin E), dramatically increased curcumin stability in phosphate buffer at physiological pH. When treated in basal cell culture medium in MC38 colon cancer cells, curcumin rapidly degraded with a half‐life of several minutes and showed a weak antiproliferative effect; co‐addition of antioxidants enhanced stability and antiproliferative effect of curcumin. Finally, co‐administration of antioxidant significantly increased plasma level of curcumin in animal models. Conclusion Together, these studies strongly suggest that a redox‐dependent mechanism plays a critical role in mediating curcumin degradation. In addition, curcumin itself, instead of its degradation products, is largely responsible for the observed biological actions of curcumin.

Trophic deprivation mediated neuronal death is important during development, acute brain or nerve trauma, and neurodegeneration. Serum deprivation (SD) approximates trophic deprivation in vitro, and an in vivo model is neuronal death in the mouse dorsal lateral geniculate nucleus (LGNd) after ablation of the visual cortex (VCA). Oxidant-induced intracellular Zn 2+ release, ([Zn 2+ ] i ), from metallothionein-3 (MT-III), mitochondria, or "protein Zn 2+ " was implicated in trophic deprivation neurotoxicity. We previously showed that neurotoxicity of extracellular Zn 2+ required entry, elevation in [Zn 2+ ] i , reduction of NAD + and ATP levels causing inhibition of glycolysis and cellular metabolism. Exogenous NAD + and sirtuin inhibition attenuated Zn 2+ neurotoxicity. Here we show that: 1) Zn 2+ is released intracellularly after oxidant and SD injuries, and sensitivity to these injuries is proportional to neuronal Zn 2+ content; 2) NAD + loss is involved; restoration of NAD + using exogenous NAD + , pyruvate, or nicotinamide attenuated these injuries, and potentiation of NAD + loss potentiated injury; 3) Neurons from genetically modified mouse strains which reduce intracellular Zn 2+ content (MT-III knockout), reduce NAD + catabolism (PARP-1 knockout), or increase expression of an NAD + synthetic enzyme (Wld s ) each had attenuated SD and oxidant neurotoxicities; 4) Sirtuin inhibitors attenuated, and sirtuin activators potentiated these neurotoxicities; 5) VCA induces Zn 2+ staining and death only in ipsilateral LGNd neurons, and a 1ppm Zn 2+ diet attenuated injury; 6) Finally, NAD + synthesis and levels are involved because LGNd neuronal death after VCA was dramatically reduced in Wld s animals, and by intraperitoneal pyruvate or nicotinamide. Zn 2+ toxicity is involved in serum and trophic deprivation induced neuronal death. Keywordsvisual cortex ablation; mouse; pyruvate; sirtuin; dorsal lateral geniculate nucleus Target deprivation mediated neuronal death plays a large role during development, trauma, and neurodegeneration. In the developing nervous system, 20-80% of all neurons produced during embryogenesis die before reaching adulthood as a result of competition between neurons for innervation of their targets. This results in matching of the size of the target cell population with the number of innervating neurons (Oppenheim, 1991;Purves et al., 1988). Target deprivation mediated neuronal death is apoptotic and occurs by programmed cell death (PCD) (Deshmukh & Johnson, 1997;Martin et al., 1998). PCD is required for the * corresponding author, FAX: (504) 568-5801, telephone: (504) 599-0880, csheli@lsuhsc.edu. NIH Public Access Author ManuscriptEur J Neurosci. Author manuscript; available in PMC 2011 September 1. Serum Deprivation Models Target Deprivation, and Both Induce an Oxidative InjuryWe and others have shown that serum deprivation (SD) induces substantial oxidative stress leading to partial ATP depletion, K + loss involving inhibition of the Na + /K + ATPase, and the apoptotic cascade . We...

Substantial pre-clinical and human studies have shown that curcumin, a dietary compound from turmeric, has a variety of health-promoting biological activities. A better understanding of the biochemical mechanisms for the health-promoting effects of curcumin could facilitate the development of effective strategies for disease prevention. Recent studies have shown that in aqueous buffer, curcumin rapidly degrades and leads to formation of various degradation products. In this review, we summarized and discussed the biological activities of chemical degradation products of curcumin, including alkaline hydrolysis products (such as ferulic acid, vanillin, ferulaldehyde, and feruloyl methane), and autoxidation products (such as bicyclopentadione). Though many of these degradation products are biologically active, they are substantially less-active compared to curcumin, supporting that chemical degradation has a limited contribution to the biological activities of curcumin.

Curcumin is among the most promising dietary compounds for cancer prevention. However, curcumin rapidly degrades in aqueous buffer at physiological pH, making it difficult to understand whether the effects of curcumin are from curcumin itself or its degradation products. Here we studied the antiproliferative and anti-inflammatory effects of curcumin degradation products, including its total degradation products (a mixture containing all stable degradation products of curcumin) and bicyclopentadione (a dominant stable degradation compound of curcumin). Curcumin potently modulated cell proliferation, progression of cell cycle, and apoptosis in MC38 colon cancer cells and inhibited lipopolysaccharide (LPS)-induced inflammatory responses and NF-κB signaling in RAW 264.7 macrophage cells. In contrast, neither the total degradation products of curcumin nor bicyclopentadione had such effects. For example, after 24 h of treatment in MC38 colon cancer cells, 5 μg/mL curcumin inhibited 39.2 ± 1.8% of cell proliferation, whereas its degradation products were inactive. Together, these results suggest that the stable chemical degradation products of curcumin are not likely to play a major role in mediating the biological activities of curcumin.