Central orchestration of peripheral nutrient partitioning and substrate utilization: implications for the metabolic syndrome

Energy homoeostasis is maintained through a complex interplay of nutrient intake and energy expenditure. The central nervous system is an essential component of this regulation, as it integrates circulating signals of hunger and satiety to develop adaptive responses at the behavioural and metabolic levels, while the hypothalamus is regarded as a particularly crucial structure in the brain in terms of energy homoeostasis. The arcuate nucleus (ARC) of the hypothalamus contains at least two intermingled neuronal populations: the neurons that produce neuropeptide Y (NPY); and the Agouti-related protein (AgRP) produced by AgRP/NPY neurons situated below the third ventricle in close proximity to proopiomelanocortin (POMC)-producing neurons. POMC neurons exert their catabolic and anorectic actions by releasing α-melanocyte-stimulating hormone (α-MSH), while AgRP neurons oppose this action by exerting tonic GABAergic inhibition of POMC neurons and releasing the melanocortin receptor inverse agonist AgRP. The release of neurotransmitters and neuropeptides by second-order AgRP neurons appears to take place on a multiple time scale, thereby allowing neuromodulation of preganglionic neuronal activity and subsequent control of nutrient partitioning - in other words, the coordinated regulation of conversion, storage and utilization of carbohydrates vs. lipids. This suggests that the function of AgRP neurons extends beyond the strict regulation of feeding to the regulation of efferent organ activity, such that AgRP neurons may now be viewed as an important bridge between central detection of nutrient availability and peripheral nutrient partitioning, thus providing a mechanistic link between obesity and obesity-related disorders.

Natural and synthetic oviposition stimulants forCatolaccus grandis (Burks) females

Oviposition behavior was elicited fromCatolaccus grandis (Burks) (Hymenoptera: Pteromalidae) females, an ectoparasitoid of the boll weevil,Anthonomus grandis Boheman (Coleoptera: Curculionidae), by smears of freshly cut cotton bolls or smears of extracts prepared with boll weevil damaged or undamaged cotton boll tissues. Oviposition behavior was also elicited fromC. grandis females by smears made withn-pentane,n-hexane,n-heptane, and isooctane. This is the first report of oviposition behavior elicited for any parasitoid by these short-chain saturated hydrocarbons (alkanes), introducing a new concept on the chemical mediation of parasitoid behavior during host selection. Oviposition behavior was also elicited fromC. grandis females by volatiles emanating from an artificial diet devoid of insect components that was specifically developed for the in vitro rearing of ectoparasitoids. The possible use of a synergistic combination ofn-hexane and diet to optimize the mechanized production of noncontaminated eggs is also discussed.

Postnatal Growth Patterns in a Chilean Cohort: The Role of SES and Family Environment

Objective. This study examined how family environmental characteristics served as mediators in the relationship between socioeconomic conditions and infant growth in a cohort of Chilean infants. Methods. We studied 999 infants, born between 1991 and 1996, from a longitudinal cohort which began as an iron deficiency anemia preventive trial. SES (Graffar Index), the Life Experiences Survey, and the Home Observation for Measurement of the Environment (HOME) were assessed in infancy. Using path analysis, we assessed the relationships between the social factors, home environment, and infant growth. Results. During the first year, weight and length gain averaged 540 grams/month and 6.5 cm/month, respectively. In the path analysis model for weight gain, higher SES and a better physical environment were positively related to higher maternal warmth, which in turn was associated with higher average weight gain. Higher SES was directly related to higher average length gain. Conclusions. In our cohort, a direct relationship between SES and length gain developed during infancy. Higher SES was indirectly related to infant weight gain through the home environment and maternal warmth. As the fastest growing infants are at risk for later obesity, new strategies are needed to encourage optimal rather than maximal growth.

Deciphering the genetic determinism of bud phenology in apple progenies: a new insight into chilling and heat requirement effects on flowering dates and positional candidate genes

The present study investigates the genetic determinism of bud phenological traits using two segregating F(1) apple (Malus × domestica) progenies. Phenological trait variability was dissected into genetic and climatic components using mixed linear modeling, and estimated best linear unbiased predictors were used for quantitative trait locus (QTL) detection. For flowering dates, year effects were decomposed into chilling and heat requirements based on a previously developed model. QTL analysis permitted the identification of two major and population-specific genomic regions on LG08 and LG09. Both 'chilling requirement' and 'heat requirement' periods influenced flowering dates, although their relative impact was dependent on the genetic background. Using the apple genome sequence data, putative candidate genes underlying one major QTL were investigated. Numerous key genes involved in cell cycle control were identified in clusters within the confidence interval of the major QTL on LG09. Our results contribute towards a better understanding of the interaction between QTLs and climatic conditions, and provide a basis for the identification of genes involved in bud growth resumption.

Abstract 2083: The stress oncoprotein LEDGF/p75 attenuates oxidative stress-induced necrosis but not apoptosis in prostate cancer cells

The lens epithelium-derived growth factor p75 (LEDGF/p75) is emerging as a stress response oncoprotein in human cancer. Our group and others showed previously that this transcription coactivator is overexpressed in major human cancers, including prostate cancer, and protects against lysosomal cell death and chemotherapeutic drugs. Although LEDGF/p75 is considered a novel anti-apoptotic protein due to its ability to attenuate lysosomal cell death, previous studies from our group demonstrated its inactivation by caspases during apoptosis. We hypothesized that LEDGF/p75 promotes resistance to stress-induced caspase-independent cell death, but not to apoptosis, in cancer cells. To test this hypothesis, we established PC3 and RWPE-2 prostate cancer cell lines stably overexpressing LEDGF/p75, and evaluated its ability to protect these cells against non-apoptotic and apoptotic insults. LEDGF/p75 significantly attenuated cytotoxicity induced by tert-butyl hydroperoxide (TBHP), a strong inducer of oxidative stress. Characterization of TBHP-induced cell death showed that it was caspase-independent since it could not be inhibited with the broad caspase inhibitor z-VAD-fmk and did not involve caspase-3 activation. Furthermore, TBHP-treated cells displayed a necrotic morphology characterized by extensive cytoplasmic fragmentation and shrunken, non-fragmented nuclei. Necrosis was also confirmed by the appearance in immunoblots of a 45 kD cleavage fragment of DNA topoisomerase that was previously established by our group as a marker of necrosis. Overexpression of LEDGF/p75 attenuated the generation of reactive oxygen species (ROS) in TBHP-treated cells. Interestingly, LEDGF/p75 also attenuated ROS in cells treated with the classical apoptosis inducers staurosporine and TRAIL, but failed to protect against these apoptotic insults. These results indicated that the ability of LEDGF/p75 to attenuate ROS is not sufficient for its pro-survival function. Analysis of LEDGF/p75 integrity by immunoblotting analysis showed that the protein remained intact in cells treated with TBHP, but was cleaved into its signature 65 kd apoptotic fragment in cells treated with staurosporine and TRAIL. Our group has shown previously that this caspase-generated fragment lacks pro-survival activity. Taken together, these results strongly suggest that overexpression of LEDGF/p75 can protect tumor cells from caspase-independent cell death processes in which this protein remains structurally intact. This study provides the basis for investigating the contribution of LEDGF/p75 to prostate cancer resistance to therapeutic modalities that induce caspase-independent cell death, as well as its potential as a novel therapeutic target.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2083. doi:10.1158/1538-7445.AM2011-2083

Abstract A108: Differential expression of peroxiredoxins in prostate cancer: Ethnic differences in the association of PRDX3 expression with clinical outcomes

Prostate cancer (PCa) is the most frequently diagnosed male cancer and the second leading cause of cancer death in men in the United States. This growing public health challenge is aggravated by disparities in the incidence and mortality of PCa among African-American (AA) men, compared to Caucasian (CC) men and other ethnic groups. The reasons for these disparities are not completely understood, although available evidence points to the convergence of multiple, interrelated factors, such as socioeconomics, unequal access to health care and screening, unhealthy lifestyle and diet, ancestry, and genetic susceptibility. Emerging evidence suggests that chronic inflammation of the prostate contributes to PCa development by inducing oxidative molecular damage, which in turns lead to the upregulation of stress and redox proteins that protect tumor cells against apoptosis and therapeutic interventions. Evaluation of the expression and role of these proteins in prostate tumors from different ethnic populations would help define molecular and cellular factors associated with prostate tumor aggressiveness and therapy resistance, and uncover potential biological determinants of PCa health disparities. The peroxiredoxin (PRDX) protein family consists of six anti-oxidant enzymes (PRDX1-6) that are emerging as key regulators of cellular anti-oxidant defense, and are being increasingly implicated in malignant transformation and therapy resistance. Very little is known about their role in prostate cancer. In this study we investigated their expression and association with clinical outcomes in prostate cancer (PCa). The expression of PRDX1-6 in PCa was evaluated in 14 cancer gene microarray datasets (from Oncomine and SPECS), by immunoblotting in a panel of 11 prostate cell lines, and by immunohistochemistry (IHC) in prostate tissue microarrays (TMA) containing tumor (n=80) and control (n=17) tissues. PRDX3 was also analyzed in TMA containing PCa tissues from AA and CC patients (n=150 per group). PRDX expression was correlated with patients’ clinicopathologic characteristics. Analysis of PRDX expression in cancer microarray databases revealed consistent upregulation (tumor vs normal) of PRDX3 and 4. All PRDXs exhibited elevated protein expression in PCa cell lines, compared with non-tumor cells. IHC revealed significant overexpression of PRDX3 and 4 in PCa, associated with increased prostate specific antigen (PSA), tumor stage, or Gleason score. High PRDX3 expression was associated with early age and elevated Gleason score at time of radical prostatectomy in AA but not in CC patients with PCa. PSA recurrence free survival in patients with low PRDX3 tumor expression was significantly longer in CC compared to AA patients, but no difference was detected for high expression. We conclude that PRDXs exhibit differential expression in prostate tumors, with PRDX3 and 4 consistently upregulated. The role of these two proteins in PCa development, and their potential as biological determinants of PCa health disparities and novel therapeutic targets, deserve further investigation.

Citation Information: Cancer Epidemiol Biomarkers Prev 2010;19(10 Suppl):A108.

Abstract 2945: Methyl CpG binding protein MeCP2 interacts with the stress-response transcription coactivator LEDGF/p75 and modulates its survival and transcription functions

The lens epithelium derived growth factor p75 (LEDGF/p75) is an emerging oncoprotein identified as a key player in the cellular response to oxidative stress. LEDGF/p75 is induced by oxidative stress and promotes resistance to stress-induced cell death presumably by transcriptionally activating specific stress and survival genes. LEDGF/p75 has a splice variant, p52, which induces cell death when overexpressed. We have shown elevated expression of LEDGF/p75 in advanced stage prostatic adenocarcinomas, most likely as a result of increased oxidative stress in the prostate tumor microenvironment. To understand the mechanisms by which LEDGF/p75 transcriptionally activate stress genes and promotes protection against oxidative stress-induced cell death, it was necessary to identify endogenous cellular interacting partners of this protein. Screening of a transcription factor protein array identified the Methyl CpG binding Protein 2 (MeCP2) as a possible interacting partner of LEDGF/p75. MeCP2 is mutated in patients with Rett syndrome, both activate and repress transcription and has been implicated in prostate tumor growth. This study was designed to validate MeCP2 as an interacting partner of LEDFG/p75 and to explore its influence on LEDGF/p75's function. To examine the interaction of MeCP2 and LEDGF, pull down assays were performed with purified GST-MeCP2 incubated with His-LEDGF/p75 or His-p52, and with GST-MeCP2 or GST-p75 incubated with U2OS cell lysates. The results suggested binding of MeCP2 to both LEDGF/p75 and p52. Co-immunoprecipitation assays using U2OS cell lysates revealed binding of proteins, detected by immunoblotting using specific anti-LEDGF/p75 or MeCP2 antibodies, suggesting interaction of both proteins in the cellular microenvironment. We also examined the intracellular localization of both proteins in U2OS cells by immunofluorescence microscopy. Both MeCP2 and LEDGF/p75 co-localized in the chromatin, showing a similar dense fine speckled staining pattern. To examine if MeCP2 influences LEDGF/p75's transcriptional activity, luciferase reporter assays were performed. Even though LEDGF/p75, p52 and MeCP2 transactivated the Hsp27 promoter (pr) individually, co-expression of LEDGF/p75 with MeCP2 increased Hsp27pr activity, while co-expression of LEDGF/p52 with MeCP2 decreased activity. In addition, LEDGF/p75 overexpression protected PC3 cells from tert-butyl hydrogen peroxide (TBHP) treatment; but siRNA knockdown of MeCP2 in these cells sensitized cells to TBHP treatment compared to control siRNA. In conclusion, our data suggest that LEDGF/p75 and MeCP2 are interacting partners and MeCP2 influences LEDGF/p75's transcription and survival function. Future studies will explore modulating the interaction between LEDGF/p75 and MeCP2 to sensitize prostate cancer cells to therapy-induced cell death.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2945.

Abstract 2715: Peroxiredoxin 3: A potential biological determinant of prostate cancer health disparities

Prostate Cancer (PCa) is the most frequently diagnosed male cancer and presents the greatest racial disparity of any cancer in the U.S., with high incidence and mortality among African American (AA) men. Eliminating these disparities requires a multi-prong approach that includes, in addition to aggressive social and public health interventions, a better understanding of the biology of prostate tumors from different ethnic groups, and the development of effective treatments for castration-resistant prostate cancer (CRPC). Our interest is to define the contribution of antioxidant and stress proteins induced by environmental factors to tumor aggressiveness and health disparities in PCa. We analyzed the expression of the peroxiredoxin (PRDX) protein family in prostate cell lines and prostate tissue microarrays (TMA), and observed a dramatic upregulation of PRDX3 in androgen responsive metastatic cell lines, particularly the AA-derived cell line MDA-PCa-2b. There was also a significant correlation between high PRDX3 tissue expression and PCa (when compared to normal tissues), advanced tumor stage, and elevated PSA (P<0.05). These observations prompted an analysis of PRDX3 protein expression in ethnicity PCa TMAs containing 150 cases from AA PCa patients and 150 cases from Caucasian (CC) PCa patients, plus normal prostate tissues. Although we did not observe significant differences in the percent of PRDX3-positive immunostained prostate tumor tissues when comparing AA vs CC tissues, high PRDX3 expression correlated with early age at diagnosis (P<0.01) and elevated Gleason score (P<0.05) in the AA group but not in the CC group (P=0.459 and P=0.3394, respectively). We also examined the association between PRDX3 prostate tumor tissue expression and PSA recurrence free survival in AA and CC patients for which disease progression data was available. PSA recurrence free survival in patients with low PRDX3 tumor expression was longer in the CC group than in the AA group (P<0.05, log rank test), suggesting a correlation with a more favorable prognosis for the CC patients. However, no statistically significant difference in PSA recurrence free survival was detected in patients with high PRDX3 expression, when both groups were compared (P=0.159). These results could be interpreted as that high PRDX3 expression in prostate tumors is associated with a less favorable prognosis regardless of ethnicity, whereas low PRDX3 expression is associated with a less favorable prognosis in AA patients compared to CC patients. The contribution of PRDX3 to these differences is unclear, but taken together the data suggest that the presence of PRDX3 (low or high) in prostate tumors from AA patients could be associated with a more aggressive disease phenotype. These results warrant further investigation of the significance of PRDX3 expression in prostate tumors, and exploiting PRDX3 as a novel therapeutic target for CRPC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2715.

Acoustic barriers obtained from industrial wastes

Acoustic pollution is an environmental problem that is becoming increasingly more important in our society. Likewise, the accumulation of generated waste and the need for waste management are also becoming more and more pressing. In this study we describe a new material--called PROUSO--obtained from industrial wastes. PROUSO has a variety of commercial and engineering, as well as building, applications. The main raw materials used for this environmentally friendly material come from slag from the aluminium recycling process, dust from the marble industry, foundry sands, and recycled expanded polystyrene from recycled packaging. Some natural materials, such as plastic clays, are also used. To obtain PROUSO we used a conventional ceramic process, forming new mineral phases and incorporating polluted elements into the structure. Its physical properties make PROUSO an excellent acoustic and thermal insulation material. It absorbs 95% of the sound in the frequency band of the 500 Hz. Its compressive strength makes it ideal for use in ceramic wall building.

Expression of chick Fgf19 and mouse Fgf15 orthologs is regulated in the developing brain by Fgf8 and Shh

Fibroblast growth factors (Fgfs) constitute a family of signaling molecules that play essential roles in development. We have studied the expression pattern of mouse Fgf15 in the developing brain. Fgf19 is another member of the FGF family that has been suggested as the chick and human ortholog of mouse and rat Fgf15. Here, we compare the expression pattern during neural development of chick Fgf19 with mouse Fgf15. Unlike Fgf15, Fgf19 presents an expression in the isthmic alar plate, diencephalic and mesencephalic parabasal plates, hindbrain basal plate, as well as in the zona limitans intrathalamica (zli). Moreover, we explored the regulation between Fgf19 and the signaling molecules of the isthmic and zli organizers: Fgf8 and Shh, respectively. Considering the possibility that Fgf19 plays a similar role in humans and chicks, this finding could explain the significant diencephalic phenotypic differences between humans and mice in models and diseases where the Shh pathway is affected.

Developmental mechanisms and experimental models to understand forebrain malformative diseases

The development of the central nervous system can be divided into a number of phases, each of which can be subject of genetic or epigenetic alterations that may originate particular developmental disorders. In recent years, much progress has been made in elucidating the molecular and cellular mechanisms by which the vertebrate forebrain develops. Therefore, our understanding of major developmental brain disorders such as cortical malformations and neuronal migration disorders has significantly increased. In this review, we will describe the major stages in forebrain morphogenesis and regionalization, with special emphasis on developmental molecular mechanisms derailing telencephalic development with subsequent damage to cortical function. Because animal models, mainly mouse, have been fundamental for this progress, we will also describe some characteristic mouse models that have been capital to explore these molecular mechanisms of malformative diseases of the human brain. Although most of the genes involved in the regulation of basic developmental processes are conserved among vertebrates, the extrapolation of mouse data to corresponding gene expression and function in humans needs careful individual analysis in each functional system.

Heavy metal-rich wastes sequester in mineral phases through a glass-ceramic process

Certain sludges generated by industry are rich in contaminating elements and are a major environmental problem. In this study, we determine the ability of these contaminating elements to be incorporated into a glass-matrix and in various mineral phases after a crystallization process. The contaminating elements studied were obtained from sewage sludges (SS) and galvanic sludges (GS), our raw materials. The sludge samples were taken from urban wastewater treatment plant in Catalonia (NE Spain) with high levels of phosphorus oxide (P(2)O(5)). In silica glasses, P(2)O(5) acts as a network former. We determined the chemical composition of both the SS and GS, as well as their thermal behaviour by differential thermal analysis and thermal gravimetric analysis (DTA-TG) to obtain their melting curves. The vitreous transition temperature of the obtained glass was established by dilatometer technique at 725 degrees C. The DTA-TG curve of the glass obtained has an exothermal wide peak at 860 degrees C corresponding to crystallization of the two phases: a spinel phase and a phosphate phase. A second exothermal wide peak at 960 degrees C was attributed to the crystallization of aluminium pyroxene, anorthite and fluor-apatite, with two exothermal phenomena attributed to the evolution of these phases. An exothermal peak at 1100 degrees C was attributed to gehlenite crystallization. Scanning electron microscope observations and energy-dispersed X-ray spectroscopy microanalyses of glass-ceramic showed that the contaminating elements were concentrated in the spinel phases, which are the first phases to crystallize during the cooling of glass. Finally, the spinel structure permits the incorporation of all the contaminating elements into it.