High-resolution crystal structure and IgE recognition of the major grass pollen allergen Phl p 3

BACKGROUND

Group 2 and 3 grass pollen allergens are major allergens with high allergenic activity and exhibit structural similarity with the C-terminal portion of major group 1 allergens. In this study, we aimed to determine the crystal structure of timothy grass pollen allergen, Phl p 3, and to study its IgE recognition and cross-reactivity with group 2 and group 1 allergens.

METHODS

The three-dimensional structure of Phl p 3 was solved by X-ray crystallography and compared with the structures of group 1 and 2 grass pollen allergens. Cross-reactivity was studied using a human monoclonal antibody which inhibits allergic patients' IgE binding and by IgE inhibition experiments with patients' sera. Conformational Phl p 3 IgE epitopes were predicted with the algorithm SPADE, and Phl p 3 variants containing single point mutations in the predicted IgE binding sites were produced to analyze allergic patients' IgE binding.

RESULTS

Phl p 3 is a globular β-sandwich protein showing structural similarity to Phl p 2 and the Phl p 1-C-terminal domain. Phl p 3 showed IgE cross-reactivity with group 2 allergens but not with group 1 allergens. SPADE identified two conformational IgE epitope-containing areas, of which one overlaps with the epitope defined by the monoclonal antibody. The mutation of arginine 68 to alanine completely abolished binding of the blocking antibody. This mutation and a mutation of D13 in the predicted second IgE epitope area also reduced allergic patients' IgE binding.

CONCLUSION

Group 3 and group 2 grass pollen allergens are cross-reactive allergens containing conformational IgE epitopes. They lack relevant IgE cross-reactivity with group 1 allergens and therefore need to be included in diagnostic tests and allergen-specific treatments in addition to group 1 allergens.

Differential expression of transglutaminase genes in patients with chronic periodontitis

OBJECTIVE

Gingival epithelium plays a key role in the protection of oral tissues from microbial challenge, especially during the periodontal disease. This study was aimed to evaluate levels of mRNA transcripts of different forms of transglutaminase in the human gingival tissues from patients with chronic periodontitis and relative controls.

SUBJECTS AND METHODS

This study included 22 patients with chronic periodontitis (CP) and 22 healthy controls. For each patient, the values of probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP) were recorded. Gene expression of transglutaminase 1, transglutaminase 2, transglutaminase 3, and metalloprotease 2 was evaluated by real-time PCR, while that of Factor XIIIA and metalloprotease 9 by RT-PCR.

RESULTS

The values of all the clinical parameters were significantly higher in the CP group than in the healthy control group (P < 0.05). In the CP group, the mRNA expression of transglutaminase 1 and transglutaminase 3 was significantly decreased in comparison with healthy control group. A slight nonsignificant changes of transglutaminase 2 gene expression were observed in samples from CP patients in comparison with controls.

CONCLUSIONS

These observations suggest that transglutaminase gene expression may be modified in response to chronic injury in the damaged gingival and emphasizes the key role of these enzymes in gingival remodelling/healing and adaptive processes.

Linking altitudinal gradients and temperature responses of plant phenology in the Bavarian Alps

Global climate change influences ecosystems across the world. Alpine plant communities have already experienced serious impacts, and will continue to do so as climate change continues. The aim of our study was to determine the sensitivity of woody and herbaceous species to shifts in temperature along an altitudinal gradient. Since 1994, park rangers have been making phenological observations at 24 sites from 680 to 1425 m a.s.l. Each year 21 plant species were observed once or twice weekly from March to July; with a main focus on flowering and leaf unfolding. Our study showed a very high degree of dependence of phenophases and species on inter-annual temperature variation and altitude. Averaged over all species and phenophases, there was a delay of 3.8 days with every 100 m increase in altitude and, across all elevations, an advance of phenophases of 6 days per 1 °C increase in temperature. Temperature lapse rates assessed indirectly by phenology, as the quotient of altitudinal to temperature response coefficients, were higher than directly calculated from March to July mean temperatures, most likely due to snow effects. Furthermore, a significant difference in sensitivity to temperature change was found between growth forms (herbs versus trees). Sensitivity was less pronounced in events occurring later in the season. Our results show that species reactions will differ in magnitude during global warming. Consequently, impacts of shifts in the timing of phenological events on plant migration and plant-pollinator interactions due to rising temperatures should be considered at the species level.

Abstract P4-06-06: RNAi screen of the breast cancer genome identifies KIF14 and TLN1 as genes that modulate chemosensitivity in breast cancer

We conducted a RNA-interference screen for genes whose loss-of-function enhanced doxorubicin and docetaxel chemosensitivity in a “triple-negative,” estrogen receptor negative, progesterone receptor negative, and Her2 negative (ER− PR− Her2−) breast cancer cell line, MDA-MB-231. From ranking chemosensitivity of 334 short-hairpin RNA (shRNA) MDA-MB-231 cell lines (targeting 134 genes with known somatic mutations in breast cancer), we focused on two genes, kinesin family member 14 (KIF14) and talin (TLN1) that not only enhanced chemosensitivity but also have oncogenic annotations. KIF14 has robust expression in breast cancer cells compared to normal mammary cells. TLN1 expression is important for migration of breast cancer cells. In TLN1-deficient cells, CK19 and ZO-1 are upregulated while CK14 and snail are downregulated, suggesting that TLN1 is important for the maintenance of epithelial-mesenchymal transition in MDA-MB-231 cells. KIF14 and TLN1 loss-of-function also enhanced chemosensitivity in 3 other triple negative breast cancer cell lines (HCC1937, HCC38, and Hs578T) but not in normal human mammary epithelial cells (HMECs). Examining protein-protein-interaction networks, we identified RIP2 as a target whose inhibition via SB203580 or PP2 can further enhance chemosensitization in KIF14-deficient cells. Knock-down of a number of other known protein-protein interaction partners of KIF14 and TLN1, including FAK, CIT, ARRB2, PSTPiP1, PRC1, SVIL, ITGA2B, ITGB3, VCL and PXN, do not significantly alter doxorubicin or docetaxel chemosensitivity in MDA-MB-231 cells. Mammary fat pad xenografts of KIF14- and TLN1- deficient MDA-MB-231 cells into NOD/SCID mice demonstrated significantly less tumor mass compared to control MDA-MB-231 cells after chemotherapy. Expressions of KIF14 and TLN1 from breast cancer expression arrays improve prognostic predictions compared to clinicopathological features alone. In summary, screenings for therapeutic targets using chemotherapy and genes with known somatic mutations in breast cancer not only provide a rational targeted screen, but also present possible up-front novel treatment combinations for patients with triple negative breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-06-06.

Oxidative stress, glutathione status, sirtuin and cellular stress response in type 2 diabetes

Oxidative stress has been suggested to play a main role in the pathogenesis of type 2 diabetes mellitus and its complications. As a consequence of this increased oxidative status a cellular adaptive response occurs requiring functional chaperones, antioxidant production and protein degradation. This study was designed to evaluate systemic oxidative stress and cellular stress response in patients suffering from type 2 diabetes and in age-matched healthy subjects. Systemic oxidative stress has been evaluated by measuring plasma reduced and oxidized glutathione, as well as pentosidine, protein carbonyls lipid oxidation products 4-hydroxy-2-nonenal and F2-isoprostanes in plasma, and lymphocytes, whereas the lymphocyte levels of the heat shock proteins (HSP) HO-1, Hsp72, Sirtuin-1, Sirtuin-2 and thioredoxin reductase-1 (TrxR-1) have been measured to evaluate the systemic cellular stress response. Plasma GSH/GSSG showed a significant decrease in type 2 diabetes as compared to control group, associated with increased pentosidine, F2-isoprostanes, carbonyls and HNE levels. In addition, lymphocyte levels of HO-1, Hsp70, Trx and TrxR-1 (P<0.05 and P<0.01) in diabetic patients were higher than in normal subjects, while sirtuin-1 and sirtuin-2 protein was significantly decreased (p<0.05). In conclusion, patients affected by type 2 diabetes are under condition of systemic oxidative stress and, although the relevance of downregulation in sirtuin signal has to be fully understood, however induction of HSPs and thioredoxin protein system represent a maintained response in counteracting systemic pro-oxidant status. This article is part of a Special Issue entitled: Antioxidants and Antioxidant Treatment in Disease.

Oxidative damage in rat brain during aging: interplay between energy and metabolic key target proteins

Aging is characterized by a gradual and continuous loss of physiological functions and responses particularly marked in the central nervous system. Reactive oxygen species (ROS) can react with all major biological macromolecules such as carbohydrates, nucleic acids, lipids, and proteins. Since proteins are the major components of biological systems and regulate multiple cellular pathways, oxidative damage of key proteins are considered to be the principal molecular mechanisms leading to age-related deficits. Recent evidences support the notion that a decrease of energy metabolism in the brain contribute to neuronal loss and cognitive decline associated with aging. In the present study we identified selective protein targets which are oxidized in aged rats compared with adult rats. Most of the oxidatively modified proteins we found in the present study are key proteins involved in energy metabolism and ATP production. Oxidative modification of these proteins was associated with decreased enzyme activities. In addition, we also found decreased levels of thiol reducing system. Our study demonstrated that oxidative damage to specific proteins impairs energy metabolism and ATP production thus contributing to shift neuronal cells towards a more oxidized environment which ultimately might compromise multiple neuronal functions. These results further confirm that increased protein oxidation coupled with decreased reducing systems are characteristic hallmarks of aging and aging-related degenerative processes.

Redox proteomics in aging rat brain: involvement of mitochondrial reduced glutathione status and mitochondrial protein oxidation in the aging process

Increasing evidence supports the notion that increased oxidative stress is a fundamental cause in the aging process and in neurodegenerative diseases. As a result, a decline in cognitive function is generally associated with brain aging. Reactive oxygen species (ROS) are highly reactive intermediates, which can modify proteins, nucleic acids, and polyunsaturated fatty acids, leading to neuronal damage. Because proteins are major components of biological systems and play key roles in a variety of cellular functions, oxidative damage to proteins represents a primary event observed in aging and age-related neurodegenerative disorders. In the present study, with a redox proteomics approach, we identified mitochondrial oxidatively modified proteins as a function of brain aging, specifically in those brain regions, such as cortex and hippocampus, that are commonly affected by the aging process. In all brain regions examined, many of the identified proteins were energy-related, such as pyruvate kinase, ATP synthase, aldolase, creatine kinase, and α-enolase. These alterations were associated with significant changes in both cytosolic and mitochondrial redox status in all brain regions analyzed. Our finding is in line with current literature postulating that free radical damage and decreased energy production are characteristic hallmarks of the aging process. In additon, our results further contribute to identifying common pathological pathways involved both in aging and in neurodegenerative disease development.

The hormetic role of dietary antioxidants in free radical-related diseases

Regular consumption of cruciferous vegetables or spices is associated with a reduced incidence of cancer and reduction of markers for neurodegenerative damage. Furthermore, greater health benefit may be obtained from raw as opposed to cooked vegetables. Nutritional interventions, by increasing dietary intake of fruits and vegetables, can retard and even reverse age-related declines in brain function and cognitive performance. The mechanisms through which dietary supplementation with antioxidants may be useful to prevent free radical-related diseases is related to their ability to counteract toxic production of both reactive oxygen and nitrogen species, along with the up-regulation of vitagenes, such as members of the heat shock protein (Hsp) family heme oxygenase-1 and Hsp70. The most prominent dietary factor that affects the risk of many different chronic diseases is energy intake - excessive calorie intake increases the risk. Reducing energy intake by controlled caloric restriction or intermittent fasting increases lifespan and protects various tissues against diseases, in part, by hormetic mechanisms that increase cellular stress resistance. This biphasic dose-response relationship, referred to here as hormesis, display low-dose stimulation and a high-dose inhibition. Despite the current interest in hormesis by the toxicology community, quantitatively similar U-shaped dose responses have long been recognized by researchers to be involved with factors affecting memory, learning, and performance, as well as nutritional antioxidants and oxidative stress-mediated degenerative reactions. Dietary polyphenols present strong cytoprotective effects, however under uncontrolled nutritional supplementation gene induction effects and the interaction with detoxification responses can have negative consequences through the generation of more reactive and harmful intermediates.

Aspirin, NSAIDs, risk of dementia, and influence of the apolipoprotein E epsilon 4 allele in an elderly population

In a cohort study, 1,301 subjects free of dementia at baseline in the Kungsholmen Project were followed up to 6 years. We studied the association between use of aspirin and non-steroidal anti-inflammatory drugs (NSAIDs), incidence of Alzheimer's disease (AD) and overall dementia, and the influence of the apolipoprotein E epsilon4 allele. In stratified analyses, a relative risk (RR) of 1.80 (95% CI 1.14-2.83) for AD was seen, in the apoE epsilon4-negative group using aspirin. This implicates a possible different mechanism of developing AD in this group. We also found a possible protective effect of NSAIDs against AD, since no one who used NSAIDs for around 3 years had developed AD 3 years later. One user developed vascular dementia, and a low point value of risk was seen, however, not significant (RR 0.23; 95% CI 0.03-1.68). This could be due to the small samples in our study, or to comorbidity contributing to the development of dementia in this elderly population.

Levels of serum creatinine and estimated creatinine clearance over the age of 75: a study of an elderly Swedish population

Serum creatinine was measured and creatinine clearance estimated using the Cockcroft-Gault (C-G) formula, in elderly people participating in a population study of the elderly, the Kungsholmen Project. This is an ongoing longitudinal study which was begun in 1987 and comprised all people in a district of Stockholm, born in 1912 or earlier. Out of 2368 people 1810 participated. In 1362 cases, serum creatinine and an estimation of the creatinine clearance could be obtained. The mean age of these elderly people was 81 years, and 92% were living in their own homes. A linear regression model showed that the weight of the elderly decreased by age, indicating a decrease in muscle mass. However, this was not accompanied by a decrease in serum creatinine levels. When creatinine clearance was estimated using the C-G formula, a significant decline with age was seen at an average rate of 1.2 ml/min per year. It declined from 52 ml/min at age 75 to 27 ml/min at age 95. The mean for the whole study group was 44.6 ml/min. Our data suggest that the glomerular filtration rate may be very low in the oldest old and that there is a continuing decline with increasing age, even in a population where a high number of the elderly are still living in their own homes. Furthermore, the lack of major changes in serum creatinine levels with age supports the idea that this parameter is not a reliable measure of renal function in the elderly.

Use of cardiovascular drugs in an older Swedish population

OBJECTIVE

To describe the use of cardiovascular drugs in an older population with respect to age, sex, housing type, and creatinine clearance.

DESIGN

A cross-sectional survey.

PARTICIPANTS

All residents of a district of Stockholm (Kungsholmen), Sweden, aged 75 and older, living in institutions or at home.

MEASUREMENTS

Cardiovascular drug use, serum creatinine, electrolytes, height, weight, and symptoms.

RESULTS

A total of 43 cardiovascular (CV) drugs were used. The most common drugs were digoxin (used by 18.2%), furosemide (16.4%), and glyceryl trinitrate (12.4%). Drugs with an antihypertensive effect accounted for 61% of all CV drugs. CV drug use increased with age for cardiac glycosides and diuretics, but decreased with age for calcium antagonists and beta-blockers. Drug doses tended to be less than the recommended daily dose except for a few drugs, e.g., furosemide. There was a trend toward decreasing dose with increasing age, but this was not significant. Diuretics were the only CV drugs used more often in women. People living in institutional care used the least amount of CV drugs. The dose of drugs taken did not appear to be related to estimated creatinine clearance. Comparisons between drug use and complaint of symptoms showed a strong correlation between the use of cardiac glycosides and anorexia, calcium antagonists and constipation, and nitrates and vertigo. There were weaker correlations with cardiac glycosides and visual disturbances and with potassium sparing diuretics and a high potassium.

CONCLUSIONS

CV drugs are used commonly in older people. We suggest that the symptoms correlating with cardiac glycoside use may be signs of unrecognized toxicity, and this may relate to our finding that drug use is often not tailored to renal function as measured by creatinine clearance.

The use of medicines with anticholinergic effects in older people: a population study in an urban area of Sweden

OBJECTIVE

To investigate the use of medicines with anticholinergic properties among older people in an urban population in Sweden.

DESIGN

A cross-sectional survey.

SETTING

Ordinary homes, sheltered accommodations, nursing homes, and geriatric departments.

PARTICIPANTS

All residents aged 75 and older in a district of Stockholm, Sweden.

MEASUREMENTS

Structured interviews with older persons, their relatives and/or health care personnel; prescription forms; medical records.

RESULTS

The overall use of medicines with anticholinergic effects was comparatively low. Doses of these medicines were also generally low. Concurrent use of several such medicines was uncommon. The most prevalent therapeutic/pharmacological group was neuroleptics. In contrast, antidepressants were used by few older people. The prevalence of medicines with anticholinergic effects was highest at institutions, where neuroleptics were frequent and use of low-potency neuroleptics was not uncommon.

CONCLUSION

Our results indicate that the risk of anticholinergic side effects may be quite low in the present population as a whole. However, there may be grounds for revising the therapy in institutions, where the use of neuroleptics was shown to be high and low-potency neuroleptics, known to have a higher incidence of anticholinergic side effects, were not avoided.

Osmotic fragility of erythrocytes in Bolivian and Brazilian squirrel monkeys (Saimiri sciureus)

Median corpuscular fragility of erythrocytes does not differ significantly between fed and fasted Bolivian and Brazilian squirrel monkeys and are similar to values reported in humans and rhesus monkeys. This report further confirms that the fasting hyperbilirubinemia present only in Bolivian squirrel monkeys with a Gilbert-like syndrome is not due to an increased fragility of erythrocytes and should be classified as a nonhemolytic hyperbilirubinemia.

Liver function studies on rhesus monkeys (Macaca mulatta) following the administration of hydrazine sulfate

Hydrazine sulfate (Hs), a known occupational toxin and putative cancer therapeutic agent, was administered iv at various doses to rhesus monkeys in an effort to measure its effects upon the liver. Function tests included indocyanine clearance (ICG Vmax and Km), serum bile acid levels and serum enzyme activities, including alanine aminotransferase, gamma glutamyl transferase, and a panel of 19 other blood chemical constituents. Hepatic function and other biochemical tests were generally within the normal range following single-dose Hs administration (10-40 mg/kg) and did not suggest the presence of significant liver injury. Two monkeys receiving 80 mg/kg Hs exhibited extensive hepatic lipidosis without biochemical or histologic signs of necrosis. Hs, administered iv, appears to produce little or no hepatic toxicity.