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Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by progressive joint inflammation, resulting in cartilage destruction and bone erosion. It was reported that low-dose radiation modulates immune disease. Here, we investigated whether low-dose whole-body irradiation has preventive and therapeutic effects in collagen-induced RA (CIA) mouse models. Fractionated low-dose irradiation (0.05 Gy/fraction, total doses of 0.1, 0.5 or 0.8 Gy) was administered either concurrently with CIA induction by Type II collagen immunization (preventive) or after CIA development (therapeutic). The severity of CIA was monitored using two clinical parameters, paw swelling and redness. We also measured total Immunoglobulin G (IgG) and inflammatory cytokines (interleukine (IL)-6, IL-1β and tumor necrosis factor-alpha (TNF-α)) in the serum by enzyme-linked immunosorbent assay, and we evaluated histological changes in the ankle joints by immunohistochemistry and hematoxylin and eosin staining. Low-dose irradiation reduced CIA clinical scores by up to 41% in the preventive model and by 28% in the therapeutic model, while irradiation in the preventive model reduced the typical CIA incidence rate from 82 to 56%. In addition, low-dose irradiation in the preventive model decreased total IgG by up to 23% and decreased IL-1β and TNF-α by 69 and 67%, and in the therapeutic model, decreased total IgG by up to 35% and decreased IL-1β and IL-6 by 59 and 42% with statistical significance (P< 0.01, 0.05 and 0.001). Our findings demonstrate that low-dose radiation has preventive and therapeutic anti-inflammatory effects against CIA by controlling the immune response, suggesting that low-dose radiation may represent an alternative therapy for RA, a chronic degenerative immune disease.

AbstractGuanine is the most strongly oxidized base in DNA; generation of a guanine radical cation as an intermediate in an oxidation reaction leads to migration through a resulting cationic hole in the DNA π-stack until it is trapped by irreversible reaction with water or other free radicals. In the case of normal sequences, the primary position of Guanine oxidations by one-electron oxidants such as carbonate radical anions, BPT(7,8,9,10-tetrahydroxytetrahydrobenzo[a]pyrene), and riboflavin are 5′-G in GG doublets and the central G in a GGG triplet. According to results, the properties of guanine oxidation on abasic site containing sequences are independent from the position of AP(apurinic/apyrimidinic) site in the presence of carbonate radical anions under a short irradiation time, although this radical is exposed to solvent by the existence of an abasic site. The lack of abasic site effect on guanine oxidative damage by the carbonate radical may be due to a sequence-independent property of the initial electron transfer rate in the hole injection step, or may relate to an electron transfer mechanism with large reorganization energy dependency. Consequently, the carbonate radical anions may easily migrate to another single G in the charge re-distribution step. Meanwhile, there is a strong dependency on the presence of an AP(apurinic/apyrimidinic) site in the cleavage patterns of guanine oxidations by physically large oxidizing agents, such as BPT(7,8,9,10-tetrahydroxytetrahydrobenzo[a]pyrene) and riboflavin. These radicals show strong AP(apurinic/apyrimidinic) site dependency and clear G-site selectivity.Communicated by Ramaswamy H. Sarma

AbstractThe spectral properties of meso-tetrakis (N-methylpyridinium-4-yl)porphyrin (TMPyP) in the presence of parallel and antiparallel G-quadruplexes formed from a thrombin-binding aptamer G-quadruplex (5′-G3T2G3TGTG3T2G3) were investigated in this study. Red shift and hypochromism in the Soret absorption band of TMPyP were observed after binding to both parallel and antiparallel G-quadruplexes. The extent of changes in the absorption spectra were similar for both conformers. No circular dichroism spectrum was induced in the Soret region for both parallel and antiparallel G-quadruplexes. This is suggest that there is no or very weak interaction between electric transitions of nucleobases and porphyrin molecule. The accessibility of the neutral quencher I2to the G-quadruplex-bound TMPyP was similar for both parallel and antiparallel G-quadruplexes. All these observations suggest that TMPyP was bound at the outside of the quadruplexes, and conceivably interacted with the phosphate group via a weak electrostatic interaction.Communicated by Ramaswamy H. Sarma

We present an overview of important results obtained during the first 20 years of the Multicenter Allergy Study (MAS), one of the first and longest-running population-based birth cohorts focusing on asthma and allergy.

Meso-tetrakis(N-methyl pyridinium-4-yl)porphyrin (TMPyP) intercalates between the base-pairs of DNA at a low [TMPyP]/[DNA base] ratio in aqueous solutions and molecular crowding conditions, which is induced by the addition of Poly(ethylene glycol) (PEG). Studied DNA-binding drugs, including TMPyP, 9-aminoacridine, ethidium bromide, and DAPI (4′,6-diamidino-2-phenylindole) showed similar binding properties in the presence or absence of PEG molecules which is examined by circular and linear dichroism. According to the LDr(reduced linear dichroism) results of the binding drugs examined in this work, PEG molecules induced no significant change compared to their binding properties in aqueous buffering systems. These results suggest that the transition moments are not expected to be perturbed significantly by PEG molecules. In this study, the experimental conditions of PEG 8000 were maintained at 35% (v/v) of total reaction volume, which is equal to the optimal molar concentration (0.0536 M as final concentration for PEG 8000) to maintain suitable cell-like conditions. Therefore, there was no need to focus on the conformational changes of the DNA helical structure, such as forming irregular aggregate structures, induced by large quantities of molecular crowding media itself at this stage.

Allergic rhinitis is the most common clinical presentation of allergy, affecting 400 million people worldwide, with increasing incidence in westernized countries1,2. To elucidate the genetic architecture and understand the underlying disease mechanisms, we carried out a meta-analysis of allergic rhinitis in 59,762 cases and 152,358 controls of European ancestry and identified a total of 41 risk loci for allergic rhinitis, including 20 loci not previously associated with allergic rhinitis, which were confirmed in a replication phase of 60,720 cases and 618,527 controls. Functional annotation implicated genes involved in various immune pathways, and fine mapping of the HLA region suggested amino acid variants important for antigen binding. We further performed genome-wide association study (GWAS) analyses of allergic sensitization against inhalant allergens and nonallergic rhinitis, which suggested shared genetic mechanisms across rhinitis-related traits. Future studies of the identified loci and genes might identify novel targets for treatment and prevention of allergic rhinitis.

The interaction of Δ- and Λ-[Ru(phen)2DPPZ]2+(DPPZ = dipyrido[3,2-a:2′, 3′-c]phenazine, phen = phenanthroline) with a G-quadruplex formed from 5′-G2T2G2TGTG2T2G2–3′(15-mer) was investigated. The well-known enhancement of luminescence intensity (the ‘light-switch’ effect) was observed for the [Ru(phen)2DPPZ]2+complexes upon formation of an adduct with the G-quadruplex. The emission intensity of the G-quadruplex-bound Λ-isomer was 3-fold larger than that of the Δ-isomer when bound to the G-quadruplex, which is opposite of the result observed in the case of double stranded DNA (dsDNA); the light switch effect is larger for the dsDNA-bound Δ-isomer. In the job plot of the G-quadruplex with Δ- and Λ-[Ru(phen)2DPPZ]2+, a major inflection point for the two isomers was observed at x≈ .65, which suggests a binding stoichiometry of 2:1 for both enantiomers. When the G base at the 8th position was replaced with 6-methyl isoxanthopterin (6MI), a fluorescent guanine analog, the excited energy of 6-MI transferred to bound Δ- or Λ-[Ru(phen)2DPPZ]2+, which suggests that at least a part of both Ru(II) enantiomers is close to or in contact with the diagonal loop of the G-quadruplex. A luminescence quenching experiment using [Fe(CN)6]4-for the G-quadruplex-bound Ru(II) complex revealed downward bending curves for both enantiomers in the Stern–Volmer plot, which suggests the presence of Ru(II) complexes that are both accessible and inaccessible to the quencher and may be related to the 2:1 binding stoichiometry.

We examined common variation in asthma risk by conducting a meta-analysis of worldwide asthma genome-wide association studies (23,948 asthma cases, 118,538 controls) of individuals from ethnically diverse populations. We identified five new asthma loci, found two new associations at two known asthma loci, established asthma associations at two loci previously implicated in the comorbidity of asthma plus hay fever, and confirmed nine known loci. Investigation of pleiotropy showed large overlaps in genetic variants with autoimmune and inflammatory diseases. The enrichment in enhancer marks at asthma risk loci, especially in immune cells, suggested a major role of these loci in the regulation of immunologically related mechanisms.

Asthma, hay fever (or allergic rhinitis) and eczema (or atopic dermatitis) often coexist in the same individuals, partly because of a shared genetic origin. To identify shared risk variants, we performed a genome-wide association study (GWAS; n = 360,838) of a broad allergic disease phenotype that considers the presence of any one of these three diseases. We identified 136 independent risk variants (P < 3 × 10−8), including 73 not previously reported, which implicate 132 nearby genes in allergic disease pathophysiology. Disease-specific effects were detected for only six variants, confirming that most represent shared risk factors. Tissue-specific heritability and biological process enrichment analyses suggest that shared risk variants influence lymphocyte-mediated immunity. Six target genes provide an opportunity for drug repositioning, while for 36 genes CpG methylation was found to influence transcription independently of genetic effects. Asthma, hay fever and eczema partly coexist because they share many genetic risk variants that dysregulate the expression of immune-related genes.

The development of atopic dermatitis (AD) in infancy, and subsequent allergies such as asthma in later childhood, is known as the atopic march. The mechanism is largely unknown, yet the course of disease indicates an inter-epithelial crosstalk, through the onset of inflammation in the skin and progression to another mucosal epithelium.

Eczema and other allergic disorders are complex diseases caused by multiple genetic and environmental factors. Here, we review recent success in the identification of novel susceptibility loci for eczema.

The present review summarizes the new discoveries in the genetics of eczema, focusing on the results from the recently published first genome-wide association study.

Peroxynitrite is produced during inflammation and combines rapidly with carbon dioxide to yield the unstable nitrosoperoxycarbonate, which decomposes (in part) to CO3.−and .NO2radicals. The CO3.−radicals oxidize guanine bases in DNA through a one‐electron transfer reaction process that ultimately results in the formation of stable guanine oxidation products. Here we have explored these mechanisms, starting with a spectroscopic study of the kinetics of electron transfer from 20–22mer double‐stranded oligonucleotides to CO3.−radicals, together with the effects of base sequence on the formation of the end‐products in runs of one, two, or three contiguous guanines. The distributions of these alkali‐labile lesions were determined by gel electrophoresis methods. The cascade of events was initiated through the use of 308 nm XeCl excimer laser pulses to generate CO3.−radicals by an established method based on the photodissociation of persulfate to sulfate radicals and the oxidation of bicarbonate. Although the Saito model (Saito et al., J. Am. Chem. Soc. 1995, 117, 6406–6407) predicts relative ease of one‐electron oxidations in DNA, following the trend 5′‐⋅⋅⋅GGG⋅⋅⋅ > 5′‐⋅⋅⋅GG⋅⋅⋅ > 5′‐⋅⋅⋅G⋅⋅⋅, we found that the rate constants for CO3.−‐mediated oxidation of guanines in these sequence contexts (k5) showed only small variation within a narrow range [(1.5–3.0)×107M−1s−1]. In contrast, the distributions of the end‐products are dependent on the base sequence context and are higher at the 5′‐G in 5′‐⋅⋅⋅GG⋅⋅⋅ sequences and at the first two 5′‐guanines in the 5′‐⋅⋅⋅GGG⋅⋅⋅ sequences. These effects are attributed to a combination of initial hole distributions among the contiguous guanines and the subsequent differences in chemical reaction yields at each guanine. The lack of dependence of k5on sequence context indicates that the one‐electron oxidation of guanine in DNA by CO3.−radicals occurs by an inner‐sphere mechanism.

The Fas pathway and oxidative stress mediate neuronal death in stroke and may contribute to neurodegenerative disease. We tested the hypothesis that these two factors synergistically produce spinal motor neuron degeneration in amyotrophic lateral sclerosis (ALS). Levels of reactive oxygen species were increased in motor neurons from ALS mice compared with wild-type mice at age 10 weeks, before symptom onset. The proapoptotic proteins Fas, Fas-associated death domain, caspase 8, and caspase 3 were also elevated. Oral administration of 2-hydroxy-5-(2,3,5,6-tetrafluoro-4-trifluoromethyl-benzylamino)-benzoic acid (Neu2000), a potent antioxidant, blocked the increase in reactive oxygen species but only slightly reduced activation of proapoptotic proteins. Administration of lithium carbonate (Li+), a mood stabilizer that prevents apoptosis, blocked the apoptosis machinery without preventing oxidative stress. Neu2000 or Li+alone significantly enhanced survival time and motor function and together had an additive effect. These findings provide evidence that jointly targeting oxidative stress and Fas-mediated apoptosis can prevent neuronal loss and motor dysfunction in ALS.

Circular dichroism (CD) spectra of meso-tetrakis(N-methylpyridinium-4-yl)porphyrin (TMPyP) that are associated with various duplex and triplex AT oligomers were investigated in this study. A strong positive CD was apparent for both the TMPyP complexed with duplex d[(A-T)12]2, d(A)12·d(T)12 and triplex d(A)12·d[(T)12]2 at a low mixing ratio. As the mixing ratio increased, bisignate excitonic CD was produced for TMPyP complexed with duplexes, whereas the positive CD signal remained the same for the TMPyP-d(A)12·d[(T)12]2 complex. This difference in the CD spectrum in the presence of duplex and triplex oligomers indicates that the moderate stacking of TMPyP occurs at the major groove of the duplex and the monomeric binding occurs in (or near) the minor groove. When TMPyP forms a complex with duplex d[(A-T)6]2 only excitonic CD was observed, even at a very low mixing ratio. Therefore, at least seven or more basepairs are required for TMPyP to exhibit a monomeric CD spectrum. After close analysis of the CD spectrum, the TMPyP-poly[d(A-T)2] complex could be explained by a combination of the CD spectrum of the monomeric, moderately stacked, and extensively stacked TMPyP.

By utilizing circular and linear dichroism, the binding mode of meso-tetrakis(n-N-methylpyridiniumyl)porphyrin (n=2, 3, 4) to various DNAs was studied in this work. 2-N-(methylpyridiniumyl)porphyrin(o-TMPyP), in which rotation of the periphery pyridinium ring is prevented, exhibits similar spectral properties when bound to DNA, poly[d(G-C)2] and poly[d(A-T)2], suggesting a similar binding mode. Close analysis of the spectral properties led us to conclude that o-TMPyP sits in the major groove. However, both 3-N- and 4-N-(methylpyridiniumyl)porphyrin (m- and p-TMPyP), of which the periphery pyridinium ring is free to rotate, intercalate between the basepairs of DNA and poly[d(G-C)2]. In the presence of poly[d(A-T)2], m-TMPyP exhibits a typical bisignate excitonic CD spectrum in the Soret band, while p-TMPyP shows two positive CD bands. The excitonic CD spectrum of the m-TMPyP-poly[d(A-T)2] complex and the positive CD band of the o-TMPyP-poly[d(A-T)2] complex were not affected by the presence of the minor groove binding drug, 4′,6-diamidino-2-phenylindole (DAPI), indicating that this porphyrin is bound in the major groove. In contrast, two positive CD bands of the p-TMPyP-poly[d(A-T)2] complex altered in the presence of DAPI. From the changes in CD spectrum and other spectral properties, a few possible binding modes for p-TMPyP to poly[d(A-T)2] are suggested.

Postnatal development of liver tyrosine aminotransferase and glucose-6-phosphatase, expressed as activity per gram of liver, occurred as rapidly in pups from pregnant rats fed throughout gestation a diet containing only 4% of casein as in pups from those fed the control diet containing 18% of casein supplemented with 0.3% of L-methionine. Total enzyme activity per liver was lower in pups from protein-restricted dams due to their smaller liver size. Dams fed the 4% casein diet during pregnancy gained much less weight than those fed the control diet and produced pups that weighed significantly less than control pups. Reproductive performance of a few dams fed 6% casein diets with or without amino acid supplements during gestation was comparable to that of dams fed the control diet. Litter size was not significantly reduced by the low-protein intake.

The relationship between liver histidase activity and histidine catabolism was studied in rats fed L-amino acid diets containing 0.1, 0.25, 0.6, 1.2, or 3.0% of L-histidine, after they had been fed either 15 or 80% casein diets to induce different levels of liver histidase. On days 2 and 10, rats from each group were fed L-[U-14C]histidine with their respective diets and expired 14CO2was measured. On day 2, liver histidase activity of rats that had been fed 80% casein previously was about 3.5 times that of rats that had been fed 15% casein previously; histidase activity was not influenced by the histidine content of the diet fed subsequently. The proportion of absorbed histidine oxidized was low regardless of prior treatment until histidine intake met the requirement. When histidine intake exceeded the requirement the proportion of absorbed histidine oxidized by rats previously fed 15% casein increased but, with 3.0% of histidine in the diet, their capacity for oxidation was exceeded as indicated by the large accumulation of histidine in tissues. When histidine intake exceeded the requirement, rats previously fed 80% casein oxidized more histidine than those previously fed 15% casein and maintained relatively low tissue histidine concentrations even with 3% of histidine in the diet. On day 10, histidase activity of rats previously fed 80% casein had fallen by about 50% and their capacity to oxidize histidine was significantly less than on day 2. These results suggest that with low dietary levels of histidine, histidine concentration is the major factor regulating histidine metabolism but with high dietary levels of histidine, histidase content becomes important for catabolism of excess histidine and maintenance of low tissue histidine concentrations. J. Nutr. 109: 291-299, 1979.

The metabolic fate of threonine was investigated in young male rats fed 15% amino acid diets containing from 0.15% to 0.85% of l-threonine. Liver serine-threonine dehydratase (S-TDH) activity did not increase with increasing dietary threonine content. The level of threonine required for maximum weight gain was not greater than 0.55% of the diet (or about 600 μmoles/day). Tissue free threonine content of rats fed the diets with 0.15% or 0.3% of threonine was very low but increased sharply with increasing dietary threonine content above 0.3%. During ad libitum feeding of these diets containing l-[U-14C]threonine, rate of oxidation of threonine was low when intake was in the range of the requirement for maximum growth, but increased, thereafter as threonine intake increased. A 30-fold induction of liver S-TDH, by prior feeding of an 80% casein diet, did not result in increased oxidation of threonine when dietary threonine content was 0.15%. When dietary threonine content was increased to 0.5%, oxidation of threonine increased slightly but significantly. With 3% of threonine in the diet, rats previously fed a 15% casein diet had extremely high tissue threonine concentrations whereas those with high S-TDH activity, due to the previous feeding of the 80% casein diet, oxidized threonine rapidly and tissue threonine concentrations were elevated much less.

The metabolic fate of histidine was investigated in young male rats fed diets containing from 0 to 0.6% of L-histidine and 14.7% of a mixture of other L-amino acids. Liver histidase activity was not influenced by dietary histidine content. Tissue histidine concentration increased gradually, then more sharply, as dietary histidine content was increased from 0 to 0.325% then it plateaued. During ad libitum consumption of these diets containing L-[U-14C]histidine, 14CO2production remained low until dietary histidine content exceeded 0.25%, then it increased linearly until with 0.6% of dietary histidine 25% of the absorbed dose was oxidized. The proportion of absorbed 14C incorporated into tissue proteins was high when dietary histidine content was low and decreased as dietary histidine content increased. Histidine requirement estimated from the inflection point of the oxidation curve was in good agreement with values determined from growth response and urinary nitrogen excretion. Liver histidase activity increased almost linearly with increasing dietary casein content. Rats fed 12% casein oxidized more of a load of L-[ring-2-14C]histidine (500 mg/100 g rat) to CO2than those fed 8% casein. Plasma histidine clearance rate after intraperitoneal injection of 50 mg histidine/100 g rat increased as the casein content of the diet was increased from 4% to 8%, 12% and 40%.

Male rats fed a 12% casein diet without choline were injected i.p. daily for 2 or 5 weeks with either saline or 6, 20 or 60 mg of nicotinamide (NAM) per 100 g body weight. Weight gain, food intake and gain/food were lower for the NAM-treated groups compared to the controls. Urinary excretion of the major metabolite, N1-methylnicotinamide (NMN) increased with increasing dose of NAM. NAM administration did not alter the activity of hepatic nicotinamide methyltransferase. Excretion of another metabolite, N1-methyl-2-pyridone-5-carboxamide (2-PYR) was low and showed minimal changes in response to NAM administration. NAM administration did not affect urinary creatinine excretion. Livers of the NAM-injected groups were hypertrophied, and the total lipid content was increased. Kidney hypertrophy was also noted. Plasma and liver choline levels were decreased in response to NAM administration. We conclude that chronic NAM administration resulted in a methyl-group deficiency state due to the greatly increased need for methylation of NAM.

In the version of this article initially published, in Fig. 3, the y-axis numbering did not match the log scale indicated in the axis label. The error has been corrected in the HTML and PDF version of the article.