Epigenetic regulation of interleukin-8, an inflammatory chemokine, in osteoarthritis

OBJECTIVE

To determine whether altered IL8 methylation status is associated with increased expression of IL8 in human osteoarthritic (OA) chondrocytes.

METHODS

IL8 expression levels and the percentage CpG methylation in human chondrocytes were quantified by qRT-PCR and pyrosequencing in OA patients and in non-OA osteoporotic controls. The effect of CpG methylation on IL8 promoter activity was determined using a CpG-free vector; co-transfections with expression vectors encoding nuclear factor-kappa B (NF-κB), AP-1 and C/EBP were subsequently undertaken to analyse for IL8 promoter activity in response to changes in methylation status.

RESULTS

IL8 expression in OA patients was 37-fold higher than in osteoporotic controls. Three CpG sites in the IL8 promoter were significantly demethylated in OA patients. Multiple regression analysis revealed that the degree of methylation of the CpG site located at -116-bp was the strongest predictor of IL8 expression. In vitro DNA methylation was noted to decrease IL8 promoter basal activity. Furthermore, NF-κB, AP-1 and C/EBP strongly enhanced IL8 promoter activity whilst DNA methylation inhibited the effects of these three transcription factors.

CONCLUSIONS

The present study demonstrates the key role of DNA methylation status on the expression of IL8 in human chondrocytes. We demonstrate a quantitative relationship between percentage methylation and gene expression within clinical samples. These studies provide direct evidence linking the activation of IL8, DNA demethylation and the induction of the OA process with important therapeutic implications therein for patients with this debilitating disease.

Summing the strokes: energy economy in northern elephant seals during large-scale foraging migrations

BACKGROUND

The energy requirements of free-ranging marine mammals are challenging to measure due to cryptic and far-ranging feeding habits, but are important to quantify given the potential impacts of high-level predators on ecosystems. Given their large body size and carnivorous lifestyle, we would predict that northern elephant seals (Mirounga angustirostris) have elevated field metabolic rates (FMRs) that require high prey intake rates, especially during pregnancy. Disturbance associated with climate change or human activity is predicted to further elevate energy requirements due to an increase in locomotor costs required to accommodate a reduction in prey or time available to forage. In this study, we determined the FMRs, total energy requirements, and energy budgets of adult, female northern elephant seals. We also examined the impact of increased locomotor costs on foraging success in this species.

RESULTS

Body size, time spent at sea and reproductive status strongly influenced FMR. During the short foraging migration, FMR averaged 90.1 (SE = 1.7) kJ kg(-1)d(-1) - only 36 % greater than predicted basal metabolic rate. During the long migration, when seals were pregnant, FMRs averaged 69.4 (±3.0) kJ kg(-1)d(-1) - values approaching those predicted to be necessary to support basal metabolism in mammals of this size. Low FMRs in pregnant seals were driven by hypometabolism coupled with a positive feedback loop between improving body condition and reduced flipper stroking frequency. In contrast, three additional seals carrying large, non-streamlined instrumentation saw a four-fold increase in energy partitioned toward locomotion, resulting in elevated FMRs and only half the mass gain of normally-swimming study animals.

CONCLUSIONS

These results highlight the importance of keeping locomotion costs low for successful foraging in this species. In preparation for lactation and two fasting periods with high demands on energy reserves, migrating elephant seals utilize an economical foraging strategy whereby energy savings from reduced locomotion costs are shuttled towards somatic growth and fetal gestation. Remarkably, the energy requirements of this species, particularly during pregnancy, are 70-80 % lower than expected for mammalian carnivores, approaching or even falling below values predicted to be necessary to support basal metabolism in mammals of this size.

Simple Resistance Exercise helps Patients with Non-alcoholic Fatty Liver Disease

To date, only limited evidence has supported the notion that resistance exercise positively impacts non-alcoholic fatty liver disease. We evaluated the effects of resistance exercise on the metabolic parameters of non-alcoholic fatty liver disease (NAFLD) in 53 patients who were assigned to either a group that performed push-ups and squats 3 times weekly for 12 weeks (exercise group; n=31) or a group that did not (control; n=22). Patients in the control group proceeded with regular physical activities under a restricted diet throughout the study. The effects of the exercise were compared between the 2 groups after 12 weeks. Fat-free mass and muscle mass significantly increased, whereas hepatic steatosis grade, mean insulin and ferritin levels, and the homeostasis model assessment-estimated insulin resistance index were significantly decreased in the exercise group. Compliance with the resistance exercise program did not significantly correlate with patient background characteristics such as age, sex, BMI and metabolic complications. These findings show that resistance exercise comprising squats and push-ups helps to improve the characteristics of metabolic syndrome in patients with non-alcoholic fatty liver disease.

A Genome-wide Association Study of Periodontitis in a Japanese Population

Periodontitis is a multifactorial disease in which bacterial, lifestyle, and genetic factors are involved. Although previous genetic association studies identified several susceptibility genes for periodontitis in European populations, there is little information for Asian populations. Here, we conducted a genome-wide association study and a replication study consisting of 2,760 Japanese periodontitis patients and 15,158 Japanese controls. Although single-nucleotide polymorphisms that surpassed a stringent genome-wide significance threshold ( P < 5 × 10−8) were not identified, we found 2 suggestive loci for periodontitis: KCNQ5 on chromosome 6q13 (rs9446777, P = 4.83 × 10−6, odds ratio = 0.82) and GPR141-NME8 at chromosome 7p14.1 (rs2392510, P = 4.17 × 10−6, odds ratio = 0.87). A stratified analysis indicated that the GPR141-NME8 locus had a strong genetic effect on the susceptibility to generalized periodontitis in Japanese individuals with a history of smoking. In conclusion, this study identified 2 suggestive loci for periodontitis in a Japanese population. This study should contribute to a further understanding of genetic factors for enhanced susceptibility to periodontitis.

Syphacia muris infection delays the onset of hyperglycemia in WBN/Kob-Lepr fa rats, a new type 2 diabetes mellitus model

Diabetes mellitus is one of the most common endocrine disorders and its continuous global increase is due to factors as population growth, urbanization, aging, and increasing prevalence of obesity and physical inactivity. The effect of pinworm infection on the development of hyperglycemia was examined in WBN/K-Lepf (fa/fa) rats, a new model of the obese type 2 diabetes mellitus (T2DM) with pancreatitis. The rats were orally administered Syphacia muris eggs (infected group) and distilled water (control group). Hyperglycemia onset in the infected group was significantly delayed compared to the control group. Neither body weight nor intake of food and water were affected by S. muris infection. This study demonstrated that S. muris infection delayed the onset of T2DM in fa/fa rats and suggested that elucidation of the underlying mechanism and relevant pathways in the helminth-mediated protection may lead to the development of a new strategy to prevent diabetes mellitus.

Proton-exchange mechanism of specific Cs+ adsorption via lattice defect sites of Prussian blue filled with coordination and crystallization water molecules

We have revealed the fundamental mechanism of specific Cs(+) adsorption into Prussian blue (PB) in order to develop high-performance PB-based Cs(+) adsorbents in the wake of the Fukushima nuclear accident. We compared two types of PB nanoparticles with formulae of Fe(III)4[Fe(II)(CN)6]3·xH2O (x = 10-15) (PB-1) and (NH4)0.70Fe(III)1.10[Fe(II)(CN)6]·1.7H2O (PB-2) with respect to the Cs(+) adsorption ability. The synthesised PB-1, by a common stoichiometric aqueous reaction between 4Fe(3+) and 3[Fe(II)(CN)6](4-), showed much more efficient Cs(+) adsorption ability than did the commercially available PB-2. A high value of the number of waters of crystallization, x, of PB-1 was caused by a lot of defect sites (vacant sites) of [Fe(II)(CN)6](4-) moieties that were filled with coordination and crystallization water molecules. Hydrated Cs(+) ions were preferably adsorbed via the hydrophilic defect sites and accompanied by proton-elimination from the coordination water. The low number of hydrophilic sites of PB-2 was responsible for its insufficient Cs(+) adsorption ability.

Preferential expression of cancer/testis genes in cancer stem-like cells: proposal of a novel sub-category, cancer/testis/stem gene

Cancer/testis (CT) antigens encoded by CT genes are immunogenic antigens, and the expression of CT gene is strictly restricted to only the testis among mature organs. Therefore, CT antigens are promising candidates for cancer immunotherapy. In a previous study, we identified a novel CT antigen, DNAJB8. DNAJB8 was found to be preferentially expressed in cancer stem-like cells (CSCs)/cancer-initiating cells (CICs), and it is thus a novel CSC antigen. In this study, we hypothesized that CT genes are preferentially expressed in CSCs/CICs rather than in non-CSCs/-CICs and we examined the expression of CT genes in CSCs/CICs. The expression of 74 CT genes was evaluated in side population (SP) cells (=CSC) and main population (MP) cells (=non-CSC) derived from LHK2 lung adenocarcinoma cells, SW480 colon adenocarcinoma cells and MCF7 breast adenocarcinoma cells by RT-PCR and real-time PCR. Eighteen genes (MAGEA2, MAGEA3, MAGEA4, MAGEA6, MAGEA12, MAGEB2, GAGE1, GAGE8, SPANXA1, SPANXB1, SPANXC, XAGE2, SPA17, BORIS, PLU-1, SGY-1, TEX15 and CT45A1) showed higher expression levels in SP cells than in MP cells, whereas 10 genes (BAGE1, BAGE2, BAGE4, BAGE5, XAGE1, LIP1, D40, HCA661, TDRD1 and TPTE) showed similar expression levels in SP cells and MP cells. Thus, considerable numbers of CT genes showed preferential expression in CSCs/CICs. We therefore propose a novel sub-category of CT genes in this report: cancer/testis/stem (CTS) genes.

The octadecaneuropeptide stimulates somatolactin release from cultured goldfish pituitary cells

The present study aimed to investigate the distribution of the octadecaneuropeptide (ODN) in the goldfish brain and to look for a possible effect of ODN on somatolactin (SL) release from pituitary cells. A discrete population of ODN-immunoreactive neurones was localised in the lateral part of the nucleus lateralis tuberis. These neurones sent projections through the neurohypophyseal tract towards the neurohypophysis, and nerve fibres were seen in the close vicinity of SL-producing cells in the pars intermedia. Incubation of cultured goldfish pituitary cells with graded concentrations of ODN (10(-9) -10(-5 ) m) induced a dose-dependent stimulation of SL-β, but not SL-α, release. ODN-evoked SL release was blocked by the metabotrophic endozepine receptor antagonist cyclo(1-8) [DLeu(5) ]OP but was not affected by the central-type benzodiazepine receptor antagonist flumazenil. ODN-induced SL release was suppressed by treatment with the phospholipase C (PLC) inhibitor U-73122 but not with the protein kinase A (PKA) inhibitor H-89. These results indicate that, in fish, ODN produced by hypothalamic neurones acts as a hypophysiotrophic neuropeptide stimulating SL release. The effect of ODN is mediated through a metabotrophic endozepine receptor positively coupled to the PLC/inositol 1,4,5-trisphosphate/protein kinase C-signalling pathway.