Diversity in responses to oncolytic Lassa-vesicular stomatitis virus in patient-derived glioblastoma cells

The difficulty of glioblastoma treatment makes it a good candidate for novel therapies, such as oncolytic viruses. Vesicular stomatitis virus expressing Lassa virus glycoprotein (Lassa-VSV) showed significant promise in animal models using established glioblastoma cell lines. These experiments were to determine the susceptibility of low-passage, patient-derived cell lines to Lassa-VSV oncolysis. Four patient-derived glioblastoma cell lines were infected with Lassa-VSV that expresses green fluorescent protein (GFP) and analyzed by fluorescence microscopy, flow cytometry, and cell viability assays. Cells were also analyzed as tumorspheres containing primarily glioma stem-like cells. Three low-passage, patient-derived cells were further analyzed with RNA sequencing (RNA-seq). Individual cell lines varied somewhat in their levels of viral gene expression and time course of Lassa-VSV-induced cell death, but each was susceptible to Lassa-VSV. Brain Tumor Center of Excellence (BTCOE) 4765 cells had the highest level of expression of interferon-stimulated genes but were most susceptible to Lassa-VSV-induced cell death, indicating that more susceptible cells do not necessarily have lower interferon pathway activation. Cells cultured as tumorspheres and infected with Lassa-VSV also showed variable susceptibility to Lassa-VSV, but BTCOE 4765 cells were least susceptible. Thus, patient-derived brain tumor cells show variable responses to Lassa-VSV infection, but each of the lines was susceptible to VSV oncolysis.

Validity and Reliability of an Expanded Vegetable Questionnaire Among Elementary School Children

BACKGROUND

The purpose of this study was to expand the School Physical Activity and Nutrition questionnaire to include a greater variety of vegetables and to evaluate the relative validity and reliability of these revised items.

OBJECTIVES

This study utilized 2 convenience samples of third to fifth graders for an analysis: validity (n = 70) and reliability (n = 76). Validity was assessed by comparing questionnaire items with vegetable intake reported from a 24-hour dietary recall covering the same reference period. Reliability estimates were assessed via same-day test-retest.

RESULTS

Agreement correlations ranged from 0.35 to 0.71. Kappa statistics varied from 0.16 to 0.66. Percentage agreements ranged from 57% to 87%. Test-retest Spearman coefficients were greater than 0.50 for 6 items, weighted Kappa values were greater than 0.40 for all 7 items, and percentage agreement exceeded 75% for 5 items.

CONCLUSIONS

Results suggest that the questionnaire is a valid and reliable measure of the previous day's vegetable intake in third- to fifth-grade students. This trial was registered at ClinicalTrials.gov as NCT02668744.

Defining the caudal hypothalamic arcuate nucleus with a focus on anorexic excitatory neurons

KEY POINTS

Excitatory glutamate neurons are sparse in the rostral hypothalamic arcuate nucleus (ARC), the subregion that has received the most attention in the past. In striking contrast, excitatory neurons are far more common (by a factor of 10) in the caudal ARC, an area which has received relatively little attention. These glutamate cells may play a negative role in energy balance and food intake. They can show an increase in phosphorylated Stat-3 in the presence of leptin, are electrically excited by the anorectic neuromodulator cholecystokinin, and inhibited by orexigenic neuromodulators neuropeptide Y, met-enkephalin, dynorphin and the catecholamine dopamine. The neurons project local axonal connections that excite other ARC neurons including proopiomelanocortin neurons that can play an important role in obesity. These data are consistent with models suggesting that the ARC glutamatergic neurons may play both a rapid and a slower role in acting as anorectic neurons in CNS control of food intake and energy homeostasis.

ABSTRACT

Here we interrogate a unique class of excitatory neurons in the hypothalamic arcuate nucleus (ARC) that utilizes glutamate as a fast neurotransmitter using mice expressing GFP under control of the vesicular glutamate transporter 2 (vGluT2) promoter. These neurons show a unique distribution, synaptic characterization, cellular physiology and response to neuropeptides involved in energy homeostasis. Although apparently not previously appreciated, the caudal ARC showed a far greater density of vGluT2 cells than the rostral ARC, as seen in transgenic vGluT2-GFP mice and mRNA analysis. After food deprivation, leptin induced an increase in phosphorylated Stat-3 in vGluT2-positive neurons, indicating a response to hormonal cues of energy state. Based on whole-cell recording electrophysiology in brain slices, vGluT2 neurons were spontaneously active with a spike frequency around 2 Hz. vGluT2 cells were responsive to a number of neuropeptides related to energy homeostasis; they were excited by the anorectic peptide cholecystokinin, but inhibited by orexigenic neuropeptide Y, dynorphin and met-enkephalin, consistent with an anorexic role in energy homeostasis. Dopamine, associated with the hedonic aspect of enhancing food intake, inhibited vGluT2 neurons. Optogenetic excitation of vGluT2 cells evoked EPSCs in neighbouring neurons, indicating local synaptic excitation of other ARC neurons. Microdrop excitation of ARC glutamate cells in brain slices rapidly increased excitatory synaptic activity in anorexigenic proopiomelanocortin neurons. Together these data support the perspective that vGluT2 cells may be more prevalent in the ARC than previously appreciated, and play predominantly an anorectic role in energy metabolism.

Impact of food security on glycemic control among low-income primarily Hispanic/Latino children in Los Angeles, California: A cross-sectional study

Studies examining the impact of food insecurity on metabolic markers are limited, specifically in Hispanic youth. This study was a cross-sectional analysis of 218 3^rd-5^th grade students (83% Hispanic and 49% male). Anthropometrics, blood glucose, insulin, and lipids via fasting blood draw, dietary intake via Block screener, and a 5-item food security scale were collected. HOMA-Insulin Resistance was calculated. Multivariate analyses of covariance were used to examine differences in glucose and insulin indices, adiposity, metabolic and dietary intake variables between categories of food security. Food secure children had greater glycemic control and decreased insulin resistance compared to food insecure children.

Consumption of artificial sweetened beverages associated with adiposity and increasing HbA1c in Hispanic youth

Research examining the impact of artificial sweetened beverages (ASBs) on obesity and metabolic diseases in adolescents is limited. The overall goal is to examine the longitudinal effects of ASBs on changes in adiposity and metabolic parameters in Hispanic adolescents. Longitudinal cohort with 98 Hispanics (12-18 years) who were overweight or had obesity with the following data at baseline and 1-year later: anthropometrics, diet (24-h recalls), body composition (DXA), glucose and insulin dynamics (oral glucose tolerance and frequently sampled intravenous glucose tolerance test) and fasting lipids. Repeated measures analyses of covariance assessed changes over time between control (no ASBs at either visit), ASB initiators (no ASBs at baseline/ASBs at 1-year) and chronic ASB consumers (ASBs at both visits). ASB initiators (n = 14) and chronic ASB consumers (n = 9) compared to control (n = 75) had higher total body fat at baseline and 1-year (P = 0.05 for group effect). Chronic ASB consumers had a 6% increase in haemoglobin A1c, 34% increase in energy intake (kcal d-1 ) and 39% increase in carbohydrate intake (g d-1 ) over time, while control and ASB initiators maintained (P < 0.05 for group-by-time interactions). These results do not support promoting ASBs as a strategy for adiposity loss or to improve metabolic health.

Associations among sugar sweetened beverage intake, visceral fat, and cortisol awakening response in minority youth

CONTEXT

Abdominal adiposity has long been associated with excess caloric intake possibly resulting from increased psychosocial stress and associated cortisol dysfunction. However, the relationship of sugar-sweetened beverage (SSB) intake specifically with cortisol variability and visceral adipose tissue (VAT) is unknown.

OBJECTIVE

To examine the relationships between SSB intake, VAT, and cortisol response in minority youth.

DESIGN

A cross-sectional analysis.

SETTING

The University of Southern California.

PARTICIPANTS

60 overweight/obese Non-Hispanic Black and Hispanic adolescents ages 14-18years.

MAIN OUTCOME MEASURES

VAT via Magnet Resonance Imaging (MRI), cortisol awakening response (CAR) via multiple salivary samples, and SSB intake via multiple 24-hour diet recalls. SSB intake was divided into the following: low SSB consumers (<1 servings per day), medium SSB consumers (≥1-<2 servings per day), high SSB consumers (≥2 servings per day). Analysis of covariance were run with VAT and CAR as dependent variables and SSB intake categories (independent variable) with the following a priori covariates: sex, Tanner stage, ethnicity, caloric intake, and body mass index.

RESULTS

The high SSB intake group exhibited a 7% higher VAT compared to the low SSB intake group (β=0.25, CI:(0.03, 0.33), p=0.02). CAR was associated with VAT (β=0.31, CI:(0.01,0.23), p=0.02). The high SSB intake group exhibited 22% higher CAR compared to the low SSB intake group (β=0.30, CI:(0.02,0.48), p=0.04).

CONCLUSION

This is the first study exploring the relationship between SSB, VAT, and CAR. SSB consumption appears to be independently associated greater abdominal adiposity and higher morning cortisol variability in overweight and obese minority youth. This study highlights potential targets for interventions specifically to reduce SSB intake in a minority youth population.

Mood stabilizers inhibit cytomegalovirus infection

Cytomegalovirus (CMV) infection can generate debilitating disease in immunocompromised individuals and neonates. It is also the most common infectious cause of congenital birth defects in infected fetuses. Available anti-CMV drugs are partially effective but are limited by some toxicity, potential viral resistance, and are not recommended for fetal exposure. Valproate, valpromide, and valnoctamide have been used for many years to treat epilepsy and mood disorders. We report for the first time that, in contrast to the virus-enhancing actions of valproate, structurally related valpromide and valnoctamide evoke a substantial and specific inhibition of mouse and human CMV in vitro. In vivo, both drugs safely attenuate mouse CMV, improving survival, body weight, and developmental maturation of infected newborns. The compounds appear to act by a novel mechanism that interferes with CMV attachment to the cell. Our work provides a novel potential direction for CMV therapeutics through repositioning of agents already approved for use in psychiatric disorders.

Dietary fibre linked to decreased inflammation in overweight minority youth

OBJECTIVE

The objective of this study was to examine the relationship between diet and inflammation, and adiposity in minority youth.

DESIGN AND METHODS

The study was designed as a cross-sectional analysis of 142 overweight (≥85th body mass index percentile) Hispanic and African-American adolescents (14-18 years) with the following measures: anthropometrics, adiposity via magnetic resonance imaging, dietary intake via 24-h dietary recalls, and inflammation markers from fasting blood draws utilizing a multiplex panel. Partial correlations were estimated and analysis of covariance (ancova) models fit to examine the relationship among dietary variables, inflammation markers and adiposity measures with the following a priori covariates: Tanner stage, ethnicity, sex, total energy intake, total body fat and total lean mass.

RESULTS

Inference based on ancova models showed that the highest tertile of fibre intake (mean intake of 21.3 ± 6.1 g d(-1) ) vs. the lowest tertile of fibre intake (mean intake of 7.4 ± 1.8 g d(-1) ) was associated with 36% lower plasminogen activator inhibitor-1 (P = 0.02) and 43% lower resistin (P = 0.02), independent of covariates. Similar results were seen for insoluble fibre. No other dietary variables included in this study were associated with inflammation markers.

CONCLUSIONS

These results suggest that increases in dietary fibre could play an important role in lowering inflammation and therefore metabolic disease risk in high-risk minority youth.

Association of gestational diabetes and breastfeeding on obesity prevalence in predominately Hispanic low-income youth

OBJECTIVE

The goal of this study was to examine if breastfeeding duration by gestational diabetes mellitus status impacted the prevalence of obesity in offspring.

METHODS

Data were obtained from a 2011 phone survey with caregivers of low-income children (2-4 years) participating in the Women, Infants and Children programme in Los Angeles County. The final sample included 2295 children, 84% Hispanic and 48% female. Chi-square and binary logistic regression were used to assess gestational diabetes status and breastfeeding duration on the prevalence of obesity, with the following a priori covariates: child's ethnicity, birth weight, age in months and sex.

RESULTS

Breastfeeding and gestational diabetes were significantly associated with obesity prevalence (P < 0.01). Using gestational diabetes mellitus and no breastfeeding as the referent category, gestational diabetes mellitus offspring who were breastfed ≥12 months had a 72% decrease in obesity prevalence (adjusted odds ratio = 0.28, confidence interval 0.89-0.03, P = 0.05).

CONCLUSIONS

These findings suggest that > 12 months of breastfeeding duration in the gestational diabetes mellitus group and any duration of breastfeeding in the non-gestational diabetes mellitus mothers is needed to reduce obesity levels in a primarily Hispanic population.

Compensatory responses to insulin resistance in obese African-American and Latina girls

PURPOSE

Insulin responses to oral and intravenous glucose markedly differ by ethnicity. This study examined whether ethnic differences in pancreatic insulin secretion, hepatic insulin extraction and clearance explain these disparate findings in 35 obese African-American and 41 Latina girls (Tanner Stages: IV-V; ages: 14-18; body mass index percentile: 85.9-99.8%).

METHODS

Pancreatic insulin secretion, hepatic insulin extraction and clearance were estimated by C-peptide and insulin modeling during an oral glucose tolerance test. Insulin sensitivity (SI), acute insulin response to glucose (AIRG ) and disposition index were derived from a frequently sampled intravenous glucose tolerance test.

RESULTS

Compared to Latinas, obese African-American adolescents had lower pancreatic insulin secretion (21.3%; P < 0.01), glucose incremental area under the curve (IAUC) (41.7%, P = 0.02), C-peptide IAUC (25.1%, P < 0.01) and SI (33.7%; P < 0.01). There were no ethnic differences in hepatic insulin extraction and clearance (P's > 0.05).

CONCLUSIONS

Compensatory mechanisms to insulin resistance do not appear to explain the ethnic differences in insulin responses to oral and intravenous glucose in obese African-American and Latina girls.

Post-lesion practice and amphetamine-facilitated recovery of beam-walking in the rat

Treatment with amphetamine increases the rate of recovery of beam-walking in rats when administered after a unilateral suction-ablation lesion of the sensorimotor cortex. It is thought that amphetamine treatment must be combined with postlesion practice on the beam since confinement to prevent locomotion blocks amphetamine-facilitated recovery. However, rats which are confined are also isolated and not handled. In the present experiment, beam-walking recovery was compared among groups of rats which were treated with either amphetamine or saline and then either handled and allowed to walk in a home cage or given practice on the beam. Although amphetamine treatment and postlesion practice had independent beneficial effects on recovery, the group of rats given both treatments had the greatest improvement in beam-walking scores.

Effects of a randomized maintenance intervention on adiposity and metabolic risk factors in overweight minority adolescents

OBJECTIVE

The objective of this study was to assess the effects of a maintenance programme (monthly newsletters vs. monthly group classes and telephone behavioural sessions) on obesity and metabolic disease risk at 1 year in overweight minority adolescents.

METHODS

After a 4-month nutrition and strength training intervention, 53 overweight Latino and African-American adolescents (15.4 ± 1.1 years) were randomized into one of two maintenance groups for 8 months: monthly newsletters (n = 23) or group classes (n = 30; monthly classes + individualized behavioural telephone sessions). The following outcomes were measured at months 4 (immediately following the intense intervention) and 12: height, weight, blood pressure, body composition via BodPod™ (Life Measurement Instruments, Concord, CA, USA), lipids and glucose/insulin indices via frequently sampled intravenous glucose tolerance test.

RESULTS

There were no significant group by time interactions for any of the health outcomes. There were significant time effects in several outcomes for both groups from months 4 to 12: bench press and leg press decreased by 5% and 14%, respectively (P = 0.004 & P = 0.01), fasting insulin and acute insulin response decreased by 26% and 16%, respectively (P < 0.001 & P = 0.046); while high-density lipoprotein cholesterol and insulin sensitivity improved by 5% and 14% (P = 0.042 & P = 0.039).

CONCLUSIONS

Newsletters as opposed to group classes may suffice as follow-up maintenance programmes to decrease type 2 diabetes and cardiovascular risk in overweight minority adolescents.

Viral mutagenesis as a means for generating novel proteins

We demonstrate that a mutation-prone virus engineered to express a foreign gene is an expedient means for generating novel mutant nonviral proteins in mammalian cells. Using vesicular stomatitis virus to express a gene coding for a fluorescent DsRed protein, a number of green mutant variants including a new variant not previously described were rapidly isolated from infected cells, sequenced, and cloned. Similar methods may be useful in the development of physiologically sensitive fluorescent reporter proteins and directed evolution or mutagenesis of proteins in general.

Adiponectin and leptin are independently associated with insulin sensitivity, but not with insulin secretion or beta-cell function in overweight Hispanic adolescents

The aim of the study was to investigate the independent effects of leptin and adiponectin on insulin sensitivity as well as insulin secretion and beta-cell function in overweight Hispanic adolescents. Despite pubertal changes in hormone secretion, studies investigating the independent effect of both hormones on insulin sensitivity and beta-cell function in adolescents are lacking. In a cross-sectional study, 175 overweight Hispanic adolescent boys (n=101) and girls (n=74) with a family history of diabetes were recruited and insulin sensitivity (SI), acute insulin response to glucose (AIR), disposition index (DI), body composition, total serum adiponectin, and leptin were assessed. Over age, leptin significantly increased in girls but not in boys (p for age x gender interaction=0.005) while adiponectin was similar in boys and girls. Leptin was not correlated to adiponectin. Leptin (partial r=-0.180; p=0.019) and adiponectin (partial r=0.230; p=0.003) predicted SI independent of age, gender, body fat, lean body mass, and Tanner stage but together, they explained 5% of the unique variation in SI (p for R (2)-change<0.001). Leptin or adiponectin were not related to AIR or DI. With regard to SI, AIR, and DI, no significant gender, age, or Tanner stage interactions were observed suggesting similar effects of adiponectin and leptin among gender, age, and Tanner stages. Leptin and adiponectin were independently associated with SI, but not with insulin secretion or beta-cell function.

Combined association of maternal and paternal family history of diabetes with plasma leptin and adiponectin in overweight Hispanic children

AIMS

To investigate the importance of a maternal and paternal family history of Type 2 diabetes and their combined association with plasma leptin and adiponectin levels in overweight Latino children with a family history of Type 2 diabetes (T2DM).

METHODS

This cross-sectional study investigated the combined association of a maternal and paternal family history of T2DM with leptin and adiponectin in 175 overweight Latino children (age 11.1 +/- 1.7 years). All subjects had a family history of T2DM. Plasma adiponectin and leptin levels, body fat measured by dual-energy X-ray absorptiometry, Tanner stage, age and insulin sensitivity were assessed.

RESULTS

After adjustment for age, gestational diabetes, insulin sensitivity and body fat, a combined maternal and paternal family history of T2DM was associated with higher leptin concentrations (P = 0.004) compared with a maternal or paternal family history alone. This association was most pronounced at Tanner stage 1 (P for interaction family history x tanner stage = 0.022). The presence of a combined maternal and paternal family history of T2DM accounted for 4% (P = 0.003) of the variation in leptin concentrations. No such combined association was observed for adiponectin levels.

CONCLUSIONS

Maternal and paternal family history of T2DM may have an additive impact on leptin, but not on adiponectin levels independent of adiposity and insulin sensitivity in overweight Latino children. This may contribute to a further clinically relevant deterioration of metabolic health in this population.

Leptin-to-adiponectin ratio as independent predictor of insulin sensitivity during growth in overweight Hispanic youth

Because leptin and adiponectin are counter-regulated in vivo and exert opposing effects on glucose metabolism, fat oxidation and insulin sensitivity, the ratio of leptin-to-adiponectin has been investigated as a potential atherogenic index, suggesting that the index is a better biomarker for atherosclerotic risk in obese Type 2 diabetic patients than either leptin or adiponectin alone. However, no information is available regarding the leptin-to-adiponectin ratio during adolescence in Hispanic adolescents. Therefore, the present study was designed to investigate the leptin-to-adiponectin ratio during growth and to establish whether the leptin-to-adiponectin ratio is a better predictor for insulin sensitivity compared to leptin and adiponectin alone in a regression model. From the age of 8 to 14, the leptin-to-adiponectin ratio increased from 2.0+/-0.8 to 5.8+/-2.2 in girls, with no significant change noted in boys (gender x age interaction p=0.007). In a multiple regression analysis, including both adiponectin and leptin as independent variables, leptin and adiponectin explained 5% of the variation in insulin sensitivity independent of gender, age, Tanner stage, total fat mass and lean body mass (p for R2-change <0.001). The leptin-to-adiponectin ratio also explained 5% of the variation in insulin sensitivity, after controlling for the same covariates (p for R2-change <0.001). These data indicate that the leptin-to-adiponectin ratio is not a better predictor of insulin sensitivity during growth than the additive effects of leptin and adiponectin levels.

Mitochondrial DNA depletion analysis by pseudogene ratioing

The mitochondrial DNA (mtDNA) depletion status of rho(0) cell lines is typically assessed by hybridization or polymerase chain reaction (PCR) experiments, in which the failure to hybridize mtDNA or amplify mtDNA using mtDNA-directed primers suggests thorough mitochondrial genome removal. Here, we report the use of an mtDNA pseudogene ratioing technique for the additional confirmation of rho0 status. Total genomic DNA from a U251 human glioma cell line treated with ethidium bromide was amplified using primers designed to anneal either mtDNA or a previously described nuclear DNA-embedded mtDNA pseudogene (mtDNApsi). The resultant PCR product was used to generate plasmid clones. Sixty-two plasmid clones were genotyped, and all arose from mtDNApsi template. These data allowed us to determine with 95% confidence that the resultant mtDNA-depleted cell line contains less than one copy of mtDNA per 10 cells. Unlike previous hybridization or PCR-based analyses of mtDNA depletion, this mtDNApsi ratioing technique does not rely on interpretation of a negative result, and may prove useful as an adjunct for the determination of rho0 status or mtDNA copy number.

Differences in the corticospinal projection from primary motor cortex and supplementary motor area to macaque upper limb motoneurons: an anatomical and electrophysiological study

To further our understanding of the functional roles of different motor cortical areas, we made a quantitative comparison of the density of corticospinal projections from primary motor cortex (M1) and supplementary motor area (SMA) to spinal motor nuclei supplying hand and finger muscles in four macaque monkeys. We also compared the action of corticospinal outputs excited by electrical stimulation of these two areas on upper limb motoneurons recorded in three anaesthetized macaques. The hand representations of SMA and M1 were first identified using structural magnetic resonance imaging scans and intracortical microstimulation. In the anatomical study we then made focal injections of wheatgerm agglutinin- horseradish peroxidase into these representations, which were subsequently confirmed by analysis of retrograde cortical labelling. Densitometric analysis showed that corticospinal projections from M1 were denser and occupied a greater proportion of the hand muscle motor nuclei than did projections from SMA. In caudal Th1 the densest projections from M1 occupied 81% of this motoneuronal area, compared with only 6% from SMA. In the electrophysiological study, bipolar intracortical stimulation of the hand representation of M1 and SMA evoked direct (D) and indirect (I) corticospinal volleys. Volleys elicited by M1 stimulation had larger amplitudes and faster conduction velocities than those evoked from the SMA. Intracellular recordings were made from 84 contralateral upper limb motoneurons. M1 and SMA stimulation evoked markedly different responses in tested motoneurons: EPSPs were larger and more common from M1 (88% of motoneurons) than from SMA (48%). Some motoneurons (16/84) showed evidence of excitatory postsynaptic potentials mediated by monosynaptic action of the D-wave evoked from M1; these early effects were not observed from the SMA. In most motoneurons (74/84) EPSPs had segmental latencies indicating that they were due to monosynaptic action of the I-wave. The results are consistent with cortico-motoneuronal (CM) connections originating from both SMA and M1 converging upon single motoneurons, but those from M1 are far more numerous and exert stronger excitatory effects than from the SMA. Thus although they may function in parallel, the two CM projections probably make different contributions to upper limb motor control.

Phosphatidylinositol-4-phosphate 5-kinase-1beta is essential for epidermal growth factor receptor-mediated endocytosis

Phosphatidylinositol-4,5-bisphosphate (PIP(2)) is known to play an important role in signal transduction and membrane trafficking. We show that one enzyme responsible for PIP(2) production, phosphatidylinositol-4-phosphate 5-kinase type 1beta (PIPKbeta), is essential for epidermal growth factor receptor (EGFR)-mediated endocytosis. Expression of murine PIPKbeta in NR6 cells expressing EGFR strikingly increased receptor internalization. Moreover, the kinase was shown to form an immunoprecipitable complex with EGFR. Expression of either a truncated kinase or a kinase dead mutant inhibited EGFR endocytosis and also blocked the membrane recruitment of PIPKbeta and both clathrin light chain and dynamin. Our results delineate a novel mechanism by which PIPKbeta regulates receptor-mediated endocytosis and receptor tyrosine kinase membrane traffic.

Endothelin receptor subtype A blockade selectively reduces pulmonary pressure after cardiopulmonary bypass

BACKGROUND

The bioactive peptide endothelin-1 is elevated during and after cardiopulmonary bypass and exerts cardiovascular effects through its 2 receptor subtypes, endothelin-1A and endothelin-1B. Increased endothelin-1A receptor stimulation after cardiopulmonary bypass can cause increased pulmonary vascular resistance and modulate myocardial contractility. However, whether and to what degree selective endothelin-1A blockade influences these parameters in the postbypass setting is not completely understood.

OBJECTIVES

Our objective was to measure left ventricular function and hemodynamics in a porcine model of cardiopulmonary bypass after selective blockade of endothelin-1A.

METHODS

Adult pigs (n = 23) underwent 90 minutes of cardiopulmonary bypass and were randomized 30 minutes after bypass to receive a selective endothelin-1A antagonist (TBC 11251, 10 mg/kg; n = 13) or saline vehicle (n = 10).

RESULTS

After bypass and before randomization, pulmonary vascular resistance rose nearly 4-fold, and left ventricular preload recruitable stroke work fell to one third of baseline values (both P <.05). In the vehicle group pulmonary vascular resistance continued to rise, and preload recruitable stroke work remained reduced. However, after endothelin-1A blockade, the rise in pulmonary vascular resistance was significantly blunted compared with that in the vehicle group. Moreover, the reduction in pulmonary vascular resistance with endothelin-1A blockade was achieved without a significant change in systemic perfusion pressures.

CONCLUSIONS

The present study demonstrated that increased activity of the endothelin-1A receptor likely contributes to alterations in pulmonary vascular resistance in the postbypass setting. Selective endothelin-1A blockade may provide a means to selectively decrease pulmonary vascular resistance without significant effects on systemic hemodynamics.

Soy isoflavone supplementation in healthy men prevents NF-kappa B activation by TNF-alpha in blood lymphocytes

Dietary intake of soy has been associated with a decreased risk of cancer. Soy isoflavones have been postulated to be the protective compounds in soybeans; however, the precise mechanism by which soy isoflavones prevent human cancer is not known. The major soy isoflavones, genistein and daidzein, are antioxidant compounds, therefore one possible mechanism of action is through their antioxidant effect. We have previously demonstrated that the soy isoflavone, genistein, inhibits the activation of the redox-sensitive transcription factor, NF-kappa B, in prostate cancer cells in vitro. In this study, we have demonstrated that genistein, but not daidzein, inhibits TNF-alpha-induced NF-kappa B activation in cultured human lymphocytes. Additionally, we investigated the in vivo effect of soy isoflavone supplementation on NF-kappa B activation induced by TNF-alpha in vitro in peripheral blood lymphocytes of six healthy men. We show that healthy male subjects receiving 50 mg isoflavone mixture (Novasoy) twice daily for 3 weeks are protected from TNF-alpha induced NF-kappa B activation. Additionally, we observed a reduction of 5-hydroxymethyl-2'-deoxyuridine (5-OHmdU), a marker for oxidative DNA damage, following isoflavone supplementation. The inhibitory effect of soy isoflavones was no longer present 3 months after the supplementation. This preliminary study demonstrates that soy isoflavone supplementation may protect cells from oxidative stress-inducing agents by inhibiting NF-kappa B activation and decreasing DNA adduct levels.

Synergy of the protein farnesyltransferase inhibitor SCH66336 and cisplatin in human cancer cell lines

The enzyme protein farnesyltransferase, which catalyzes the first step in the posttranslational modification of ras and a number of other polypeptides, has emerged as an important target for the development of anticancer agents. SCH66336 is one of the first farnesyltransferase inhibitors to undergo clinical testing. In the present study, we examined the effect of combining SCH66336 with several classes of antineoplastic drugs in various human tumor cell lines. Flow cytometry indicated that SCH66336 had no effect on the cell cycle distribution of treated cells. Nonetheless, colony-forming assays revealed that the antiproliferative effects of SCH66336 and 5-fluorouracil were less than additive. In contrast, the effects of SCH66336 and melphalan were additive. Moreover, the combination of SCH66336 + cisplatin produced antiproliferative effects that were additive or synergistic over a broad range of clinically achievable concentrations in A549 non-small cell lung cancer cells and T98G human glioblastoma cells, but less than additive in MCF-7 breast, HCT116 colon, or BxPC-3 pancreatic adenocarcinoma cells. Examination of the effect of drug sequencing in A549 cells revealed synergism when cells were exposed to SCH66336 and then cisplatin and antagonism when drugs were administered in the opposite order. The additive and synergistic effects resulted in enhanced apoptosis with the SCH66336 + cisplatin combination. Additional studies failed to show any effect of SCH66336 on the formation or removal of platinum-DNA adducts, raising the possibility that SCH66336 is affecting survival of cisplatin-treated cells downstream of the DNA lesions. These observations suggest that SCH66336 exhibits additive or synergistic effects when combined with cisplatin in a sequence- and cell line-dependent fashion. Additional preclinical and clinical study of this combination appears warranted.

The MN1-TEL fusion protein, encoded by the translocation (12;22)(p13;q11) in myeloid leukemia, is a transcription factor with transforming activity

The Tel gene (or ETV6) is the target of the translocation (12;22)(p13;q11) in myeloid leukemia. TEL is a member of the ETS family of transcription factors and contains the pointed protein interaction (PNT) domain and an ETS DNA binding domain (DBD). By contrast to other chimeric proteins that contain TEL's PNT domain, such as TEL-platelet-derived growth factor beta receptor in t(5;12)(q33;p13), MN1-TEL contains the DBD of TEL. The N-terminal MN1 moiety is rich in proline residues and contains two polyglutamine stretches, suggesting that MN1-TEL may act as a deregulated transcription factor. We now show that MN1-TEL type I, unlike TEL and MN1, transforms NIH 3T3 cells. The transforming potential depends on both N-terminal MN1 sequences and a functional TEL DBD. Furthermore, we demonstrate that MN1 has transcription activity and that MN1-TEL acts as a chimeric transcription factor on the Moloney sarcoma virus long terminal repeat and a synthetic promoter containing TEL binding sites. The transactivating capacity of MN1-TEL depended on both the DBD of TEL and sequences in MN1. MN1-TEL contributes to leukemogenesis by a mechanism distinct from that of other chimeric proteins containing TEL.

Inhibition of prostate specific antigen expression by genistein in prostate cancer cells

Recent studies have provided convincing evidence for the role of soy-isoflavones, particularly genistein, in the inhibition of prostate cancer cell growth. Prostate specific antigen (PSA) is a biological marker used to detect and monitor the treatment of prostate cancer patients. Previous studies have documented that isoflavones can inhibit the secretion of PSA in the androgen-dependent prostate cancer cell line, LNCaP, however, the effects of genistein on androgen-independent PSA expression has not been explored. In this study, we have utilized a prostate cancer cell line, VeCaP, which expresses PSA in an androgen-independent manner, to determine the effects of genistein on cell proliferation and PSA expression. Here we show that genistein inhibits cell growth similarly in both the LNCaP and VeCaP cell lines, but has differential effects on PSA expression. We demonstrate using concentrations of genistein that have been detected in the serum of humans consuming a soy-rich diet, that genistein decreases PSA mRNA, protein expression and secretion. Conversely, only high concentrations of genistein inhibited PSA expression in VeCaP cells. Additionally, we have demonstrated that genistein inhibits cell proliferation independent of PSA signaling pathways, providing further evidence to support the role of genistein as a chemopreventive/therapeutic agent for prostate cancer irrespective of androgen responsiveness.

Comparison of potential markers of farnesyltransferase inhibition

Farnesyltransferase inhibitors (FTIs) were developed to target abnormal signaling pathways that are commonly activated in neoplastic cells. Five FTIs have recently undergone Phase I testing; and two are currently in Phase II clinical trials. As part of the development of these agents, there has been interest in determining their cellular effects in the clinical setting. Several approaches have been proposed, including measurement of FT enzymatic activity, evaluation of the processing of FT polypeptide substrates, and assessment of the accumulation of p21waf1. In the present study, a number of these assays have been compared in four cultured human neoplastic cell lines of different histology (A549, HCT116, BxPC-3, and MCF-7) after treatment with the nonpeptidomimetic FTI SCH66336 and the peptidomimetic inhibitor FTI-277. Immunoblotting studies failed to demonstrate a mobility shift in ras proteins or increased accumulation of p21waf1 after treatment with these agents. In contrast, drug-induced increases in the slower migrating, unprocessed species of the chaperone protein HDJ-2 and the intranuclear intermediate filament protein lamin A were detected in all four cell lines after treatment with either agent. Unprocessed forms of both polypeptides accumulated in noncycling as well as cycling cells. The precursor peptide that is present in prelamin A but absent from mature lamin A could be readily detected by immunohistochemistry in noncycling cells with a peptide-specific antiserum. Our results indicate that unprocessed HDJ-2 and prelamin A should be suitable markers of FT inhibition in clinical samples.

A Phase I trial of the farnesyl transferase inhibitor SCH66336: evidence for biological and clinical activity

Farnesyl protein transferase (FT), an enzyme that catalyzes the first step in the posttranslational modification of ras and a number of other polypeptides, has emerged as an important target for the development of anticancer agents. SCH66336 is one of the first FT inhibitors to undergo clinical testing. We report a Phase I trial to assess the maximum tolerated dose, toxicities, and biological effectiveness of SCH66336 in inhibiting FT in vivo. Twenty patients with solid tumors received 92 courses of escalating SCH66336 doses given orally twice a day (b.i.d.) for 7 days out of every 3 weeks. Gastrointestinal toxicity (nausea, vomiting, and diarrhea) and fatigue were dose-limiting at 400 mg of SCH66336 b.i.d. Moderate reversible renal insufficiency, secondary to dehydration from gastrointestinal toxicity, was also seen. Inhibition of prelamin A farnesylation in buccal mucosa cells of patients treated with SCH66336 was demonstrated, confirming that SCH66336 inhibits protein farnesylation in vivo. One partial response was observed in a patient with previously treated metastatic non-small cell lung cancer, who remained on study for 14 months. This study not only establishes the dose for future testing on this schedule (350 mg b.i.d.) but also provides the first evidence of successful inhibition of FT in the clinical setting and the first hint of clinical activity for this class of agents.

Genistein inhibits NF-kappa B activation in prostate cancer cells

Prostate cancer is the second leading cause of cancer-related deaths in men in the United States. Epidemiological studies indicate that susceptibility to prostate cancer may be partly due to environmental influences, especially diet. An association has been shown between decreased prostate cancer risk and mortality with increased consumption of soy products, resulting in increased levels of isoflavones. We previously demonstrated that the soy isoflavone genistein inhibits cell growth and induces apoptosis in prostate cancer cells. To further elucidate the molecular mechanism by which genistein elicits its apoptotic effect, we investigated the role of a transcription factor, nuclear factor-kappa B (NF-kappa B), in the androgen-sensitive cell line LNCaP and the androgen-insensitive cell line PC3. Here we show that genistein decreases NF-kappa B DNA binding and abrogates NF-kappa B activation by DNA-damaging agents, H2O2 and tumor necrosis factor-alpha, in prostate cancer cells regardless of androgen sensitivity. Additionally, we have demonstrated that genistein reduces phosphorylation of the inhibitory protein I kappa B alpha and blocks the nuclear translocation of NF-kappa B, prohibiting DNA binding and preventing NF-kappa B activation. These results provide a mechanism by which genistein induces apoptosis in prostate cancer cells: the inactivation of NF-kappa B. Furthermore, genistein's ability to abrogate NF-kappa B activation by DNA-damaging agents strongly supports genistein's role as a chemopreventive agent.

Modulation of nucleotide sensitivity of ATP-sensitive potassium channels by phosphatidylinositol-4-phosphate 5-kinase

ATP-sensitive potassium channels (K(ATP) channels) regulate cell excitability in response to metabolic changes. K(ATP) channels are formed as a complex of a sulfonylurea receptor (SURx), a member of the ATP-binding cassette protein family, and an inward rectifier K(+) channel subunit (Kir6.x). Membrane phospholipids, in particular phosphatidylinositol (PI) 4,5-bisphosphate (PIP(2)), activate K(ATP) channels and antagonize ATP inhibition of K(ATP) channels when applied to inside-out membrane patches. To examine the physiological relevance of this regulatory mechanism, we manipulated membrane PIP(2) levels by expressing either the wild-type or an inactive form of PI-4-phosphate 5-kinase (PIP5K) in COSm6 cells and examined the ATP sensitivity of coexpressed K(ATP) channels. Channels from cells expressing the wild-type PIP5K have a 6-fold lower ATP sensitivity (K(1/2), the half maximal inhibitory concentration, approximately 60 microM) than the sensitivities from control cells (K(1/2) approximately 10 microM). An inactive form of the PIP5K had little effect on the K(1/2) of wild-type channels but increased the ATP-sensitivity of a mutant K(ATP) channel that has an intrinsically lower ATP sensitivity (from K(1/2) approximately 450 microM to K(1/2) approximately 100 microM), suggesting a decrease in membrane PIP(2) levels as a consequence of a dominant-negative effect of the inactive PIP5K. These results show that PIP5K activity, which regulates PIP(2) and PI-3,4,5-P(3) levels, is a significant determinant of the physiological nucleotide sensitivity of K(ATP) channels.

Genistein-induced upregulation of p21WAF1, downregulation of cyclin B, and induction of apoptosis in prostate cancer cells

Increased soy consumption in Asian diets, resulting in increased serum isoflavone levels, has been associated with a decreased risk for prostate adenocarcinoma (PCa). The isoflavone genistein is believed to be the anticancer agent found in soy, and significant levels of genistein have been detected in human prostatic fluid, implicating the role of genistein in PCa prevention. Recent studies have demonstrated genistein's ability to inhibit cell growth and induce apoptosis in several cell lines; however, the molecular mechanisms of genistein's effect are not known. We have evaluated the mechanism by which genistein may inhibit PCa cell growth. Here we report that genistein inhibits PCa cell growth in culture in a dose-dependent manner, which is accompanied by a G2/M cell cycle arrest. Cell growth inhibition was observed with concomitant downregulation of cyclin B, upregulation of the p21WAF1 growth-inhibitory protein, and induction of apoptosis. Collectively, these results provide experimental evidence for a novel effect of genistein on cell cycle gene regulation, resulting in the inhibition of cell growth and ultimate demise of tumor cells.

BCL-2 transduction, using a herpes simplex virus amplicon, protects hippocampal neurons from transient global ischemia

Transient global ischemia results in selective neuronal damage of hippocampal CA1 neurons. Five minutes of bilateral common carotid artery occlusion, in the Mongolian gerbil, effectively restricts forebrain blood flow, resulting in a delayed neuronal death of CA1 pyramidal cells. While there is a delay of approximately 72 h in the appearance of cell death, markers related to the mechanism of ischemic death become apparent well before neurons die. Ischemia-induced increases in the cell-death-promoting protein, bax, may disrupt the bcl-2/bax ratio necessary for normal neuronal functioning and thus promote transient ischemic death. In order to locally maintain this critical bcl-2/bax ratio and thus protect CA1 neurons from delayed neuronal death, a herpes simplex viral (HSV) vector was used to selectively introduce human bcl-2, under the control of the herpes IE 4/5 promoter, into the CA1 region of the gerbil hippocampus. Twenty-four hours prior to ischemia surgery, 1 microl of HSVbcl-2 was infused unilaterally into the CA1 region at a rate of 2 nl/min. Seventy-two hours after ischemia the animals were sacrificed and processed using Nissl, silver degeneration, and immunohistochemical (anti-human bcl-2) staining. Immunohistochemistry demonstrated both glial and neuronal bcl-2 expression around the HSVbcl-2 infusion site. The evaluation following silver degeneration staining indicated a further degeneration of CA1 neurons in the immediate area of the viral vector infusion. This damage seems to be the result of cellular debris associated with the processing of the viral amplicons. Silver degeneration staining is not present in the areas that demonstrate bcl-2 staining. These neurons appear to have been rescued from ischemic damage. This result was confirmed using the Nissl staining. Therefore, by altering the local ratio of bcl-2/bax using the HSVbcl-2 vector one may protect CA1 pyramidal cell from the delayed neuronal death of transient global ischemia.

ETO-2, a new member of the ETO-family of nuclear proteins

The t(8;21) is associated with 12-15% of acute myelogenous leukemias of the M2 subtype. The translocation results in the fusion of two genes, AML1 (CBFA2) on chromosome 21 and ETO (MTG8) on chromosome 8. AML1 encodes a DNA binding factor; the ETO protein product is less well characterized, but is thought to be a transcription factor. Here we describe the isolation and characterization of ETO-2, a murine cDNA that encodes a new member of the ETO family of proteins. ETO-2 is 75% identical to murine ETO and shares very high sequence identities over four regions of the protein with ETO (domain I-III and zinc-finger). Northern analysis identifies ETO-2 transcripts in many of the murine tissues analysed and in the developing mouse embryo. ETO-2 is also expressed in myeloid and erythroid cell lines. We confirmed the nuclear localization of ETO-2 and demonstrated that domain III and the zinc-finger region are not required for nuclear localization. We further showed that a region within ETO, containing domain II, mediates dimerization among family members. This region is conserved in the oncoprotein AML-1/ETO. The recent identification of another ETO-like protein, myeloid translocation gene-related protein 1, together with the data presented here, demonstrates that at least three ETO proteins exist with the potential to form dimers in the cell nucleus.

Regulation of ischemic cell death by glucocorticoids and adrenocorticotropic hormone

Transient global ischemia results in delayed selective neuronal death of hippocampal CA1 pyramidal cells. Glucocorticoids increase and adrenalectomy decreases the rate of neuronal death; however, they also produce changes in brain temperature, serum glucose and adrenocorticotropic hormone levels. In order to understand the role of glucocorticoids in regulating ischemic cell death, we studied RU 38486, a glucocorticoid receptor blocker, and Org 2766, a non-steroidogenic adrenocorticotropic hormone 4-9 analog. Male Mongolian gerbils were subjected to 5 min of bilateral carotid artery occlusion under a controlled temperature environment (37.0-38.0 degrees C). Animals were injected with either physiological saline, Org 2766 (10 microg/kg/24 h) or RU 38486 (50 mg/kg/8 h), beginning just prior to the occlusion until killing at either day 4 or 7. Blood was collected for serum glucose and cortisol analysis. Damage was evaluated by blinded counts of CAI neurons. Both RU 38486 and Org 2766 treatment significantly (P<0.004) reduced hippocampal CA1 damage at day 4, but not on day 7. While RU 38486 raised serum cortisol and adrenocorticotropic hormone levels, neither treatment affected temperature or serum glucose. The fact that RU 38486 mimicked adrenalectomy without changing temperature suggests that the decreased rate of cell death resulted from either removal of glucocorticoids or increases in adrenocorticotropic hormone. The ability of Org 2766 to affect this rate strongly suggests that adrenocorticotropic hormone is the active regulatory hormone rather than glucocorticoids. While both RU 38486 and Org 2766 prolong the survival of CA1 neurons after transient global ischemia, only RU 38486, which is available and tested in both animals and humans, can block the detrimental effects of post-ischemia glucocorticoid elevations. Thus, the administration of RU 38486 may be a practical adjunct to other neuroprotective agents for victims of cardiac arrest, anesthetic accidents or drowning.

Matrilineal inheritance of complex I dysfunction in a multigenerational Parkinson's disease family

Recent data suggesting complex I dysfunction in Parkinson's disease (PD) arises from mitochondrial DNA (mtDNA) mutation does not conclusively answer whether the responsible genetic lesion is inherited (primary) or somatic (secondary). To address this question, we identified a family in which multiple members over three generations are affected with PD through exclusively maternal lines. Cytoplasmic hybrids (cybrids) were created for 15 family members over two generations by transferring each individual's mtDNA to mtDNA-depleted human neuroblastoma cells. Eight of the 15 cybrid lines contained mtDNA obtained from maternally descended family members and seven contained mtDNA from paternally descended family members. After 6 weeks of culture, cybrid cell lines were assayed for complex I activity and oxidative stress, and mitochondrial morphology was analyzed by electron microscopy. Compared with the cybrid lines containing mtDNA from paternal descendants, cybrid lines containing mtDNA from maternal descendants had lower complex I activity, increased reactive oxygen species production, increased radical scavenging enzyme activities, and more abnormal mitochondrial morphologic features. These findings were present in cybrid lines containing mtDNA from maternal descendants with PD as well as in currently asymptomatic young maternal descendants, and support a precedent for inherited mtDNA mutation in some persons with PD.

Bcl-x(l) Bax interaction after transient global ischemia

Five minutes of bilateral common carotid artery occlusion in the Mongolian gerbil results in a selective, delayed death of CA1 pyramidal neurons. Although Bcl-2 appears to protect a variety of cells from cell death, the precise role of this apoptosis-regulating protein is complicated. We used immunoblots to estimate levels of Bcl-2, Bcl-x(l), and Bax at various times after carotid occlusion. Rather than Bcl-2, Bcl-x(l) appears to be the predominant neuroprotective form of this family of proto-oncogenes in the gerbil hippocampus. After transient ischemia, Bcl-2 and Bcl-x(l) protein levels remained the same. However, Bax levels were dramatically increased at 6 hours after ischemia, compared with sham-operated animals, and were still elevated at 72 hours after ischemia. To monitor dimerization interactions among theses apoptosis-regulating molecules, immunoprecipitation studies were conducted. These studies demonstrated that Bcl-x(l) association with Bax increases after ischemia. Therefore, Bax may disrupt the more favorable Bcl-x(l) (Bcl-2) interactions necessary for normal neuronal functioning and thus promote transient ischemic death.

Evidence that two reports of mtDNA cytochrome c oxidase "mutations" in Alzheimer's disease are based on nDNA pseudogenes of recent evolutionary origin

Recently, two reports [R. E. Davis et al. (1997) Proc. Natl. Acad. Sci. USA 94, 4564-4569 and E. Fahy et al. (1997) Nucleic Acids Res. 25, 3102-3109] described a series of heteroplasmic mitochondrial DNA (mtDNA) mutations in the genes encoding two cytochrome c oxidase subunits (CO1 and CO2) which segregated in higher abundance with Alzheimer's disease subjects than controls. Using mtDNA-depleted NT2 cells, we provide further evidence that these two reports are erroneously based on a PCR artifact arising from the amplification of nuclear DNA encoded mtDNA pseudogenes (mtDNA psi s). Our findings are similar, but not identical, to other recent studies of these putative mtDNA psi sequences. This sequence variability may indicate that multiple mtDNA psi s, all of comparatively recent evolutionary origin are involved. While such pseudogenes are interesting in that they provide a molecular evolutionary "snapshot" of human ancestral mtDNA, it is unlikely that they play any role in the etiology of Alzheimer's disease.

Role of apoptotic proteins in ischemic hippocampal damage

In this review, we have presented evidence that apoptotic proteins may be involved in ischemic cell death. We tried to keep in mind that focal and global ischemia almost certainly produces different forms of cell death. For example, necrotic cell death is clearly part of a focal cerebral infarct, although it is not seen in brief global insults. We also tried to make the point that not all apoptosis is the same and that various forms of non-necrotic cell death, including ischemic cell death after global ischemia, may share some of the same molecular mechanisms as classic forms of apoptosis. Finally, we wish to leave the reader with the clear impression that all the evidence is not in hand. More work needs to be done in animals to define the role of apoptotic proteins. For example, glial cells probably are important in necrosis and may play a role in ischemic cell death after transient global ischemia. Yet it is likely that glial cells die from injury in a different manner than neurons. A better understanding of these processes should lead to new therapeutic approaches that may make possible the salvaging of neurons well after an ischemic insult.

Complementation of growth factor receptor-dependent mitogenic signaling by a truncated type I phosphatidylinositol 4-phosphate 5-kinase

Substitution of phenylalanine for tyrosine at codon 809 (Y809F) of the human colony-stimulating factor 1 (CSF-1) receptor (CSF-1R) impairs ligand-stimulated tyrosine kinase activity, prevents induction of c-MYC and cyclin D1 genes, and blocks CSF-1-dependent progression through the G1 phase of the cell cycle. We devised an unbiased genetic screen to isolate genes that restore the ability of CSF-1 to stimulate growth in cells that express mutant CSF-1R (Y809F). This screen led us to identify a truncated form of the murine type Ibeta phosphatidylinositol 4-phosphate 5-kinase (mPIP5K-Ibeta). This truncated protein lacks residues 1 to 238 of mPIP5K-Ibeta and is catalytically inactive. When we transfected cells expressing CSF-1R (Y809F) with mPIP5K-Ibeta (delta1-238), CSF-1-dependent induction of c-MYC and cyclin D1 was restored and ligand-dependent cell proliferation was sustained. CSF-1 normally triggers the rapid disappearance of CSF-1R (Y809F) from the cell surface; however, transfection of cells with mPIP5K-Ibeta (delta1-238) stabilized CSF-1R (Y809F) expression on the cell surface, resulting in elevated levels of ligand-activated CSF-1R (Y809F). These results suggest a role for PIP5K-Ibeta in receptor endocytosis and that the truncated enzyme compensated for a mitogenically defective CSF-1R by interfering with this process.

Evolutionary theory and the human family

Emlen's (1995) paper "An evolutionary theory of the family" reviewed existing ideas about the nature of family systems and the reasons why they have evolved in certain animal species. His theorizing led him to propose 15 predictions about how family systems function, based on favorable evidence from various species, mostly birds. While he suggested that these predictions can be applied to the human case, he himself did not attempt to do so. We consider the applicability of Emlen's 15 predictions to the study of human family systems, and find that several aspects of the life history and ecology of Homo sapiens require that they be modified. These considerations include: (1) the importance of intragroup solidarity in the context of intergroup competition: unlike in many other species where dispersal constraints arise from food or breeding site shortages, the primary pressure driving human sociality seems to be competition from other human groups; (2) the complex nature of exchange and reciprocity in human society: reciprocal altruism in particular is integral to human social interaction and leads to a particularly high degree of non-nepotistic helping behavior; and (3) the implications of menopause and the existence of potentially dominant, postreproductive helpers: helpers of this sort have little incentive to disperse or to encourage offspring to disperse, thus greatly increasing family stability.

Nesting and shredding behavior as an indicator of hippocampal ischemic damage

Mongolian gerbils were subjected to bilateral carotid artery occlusion, exposed to nesting material and examined daily. Five minutes of ischemia significantly reduced nesting behavior for 3 days; while 10 min attenuated nesting 6 days. Semi-novel re-exposure to nesting material also resulted in deficits. These disruptions in nesting behavior directly correlate to the amount of ischemic morphological damage and thus serve as a behavioral indicator of tissue damage.

A potential role for Elf-1 in terminal transferase gene regulation

The terminal deoxynucleotidyltransferase (TdT) gene represents an attractive model for the analysis of gene regulation during an early phase of lymphocyte development. In previous studies, we identified a DNA element, termed D', which is essential for TdT promoter activity in immature lymphocytes, and two classes of D'-binding factors, Ikaros proteins and Ets proteins. Here, we report a detailed mutant analysis of the D' element which suggests that an Ets protein, rather than an Ikaros protein, activates TdT transcription. Since multiple Ets proteins are expressed in developing lymphocytes and are capable of binding to the D' element, DNA affinity chromatography was used to determine if one of the Ets proteins might bind to the D' element with a uniquely high affinity, thereby implicating that protein as a potential TdT activator. Indeed, one binding activity was greatly enriched in the high-salt eluates from a D' affinity column. Peptide microsequencing revealed that the enriched protein was Elf-1. Immunoblot analyses confirmed that in nuclear extracts, Elf-1 has a significantly higher affinity for the D' sequence than does another Ets protein, Ets-1. Transactivation and expression studies support the hypothesis that Elf-1 activates TdT transcription in immature T and B cells. Finally, a D' mutation which selectively reduces Elf-1 binding, but not the binding of other Ets proteins, was found to greatly reduce TdT promoter activity. Although Elf-1 previously had been implicated in the inducible activation of genes in mature T and B cells, our results suggest that it also plays an important role in regulating genes during an early phase of lymphocyte development.

Cloning and expression of the murine Elf-1 cDNA

The Ets family of transcription factors has been implicated in the etiology of several types of cancer. We cloned and characterized the gene encoding the murine homologue of one Ets family member, Elf-1 (mElf-1), in order to gain insight into its cellular physiology. We examined mElf-1 mRNA expression in normal mouse tissues and in several murine and human cell lines. Expression of mElf-1, although highest in lymphocytes, was observed in a number of hematopoietic cell lineages, including the myeloid, macrophages and erythroid lineages, and was lowest in the murine fibroblast cell line, NIH3T3. Analysis of human and fetal tissue mRNAs confirmed that mElf-1 is expressed in a variety of cell lineages, principally in hematopoietic cells. Western blot analysis using antiserum generated to a synthetic C-terminal peptide of mElf-1, and extracts prepared from cell lines that expressed the mElf-1 mRNA identified multiple mElf-1 species that migrated near the 97-kDa molecular weight marker. Site selection analysis indicated that the binding site preferred by mElf-1 is very similar to that of the Drosophila melanogaster homologue, E74, and to that of Fli-1, another Ets family member. We conclude that the expression of mElf-1 is not restricted to the lymphoid lineage, and suggest that Elf-1 may regulate the transcription of a broad spectrum of genes.

The t(12;21) translocation converts AML-1B from an activator to a repressor of transcription

The t(12;21) translocation is present in up to 30% of childhood B-cell acute lymphoblastic and fuses a potential dimerization motif from the ets-related factor TEL to the N terminus of AML1. The t(12;21) translocation encodes a 93-kDa fusion protein that localizes to a high-salt- and detergent-resistant nuclear compartment. This protein binds the enhancer core motif, TGTGGT, and interacts with the AML-1-binding protein, core-binding factor beta. Although TEL/AML-1B retains the C-terminal domain of AML-1B that is required for transactivation of the T-cell receptor beta enhancer, it fails to activate transcription but rather inhibits the basal activity of this enhancer. TEL/AML-1B efficiently interferes with AML-1B dependent transactivation of the T-cell receptor beta enhancer, and coexpression of wild-type TEL does not reverse this inhibition. The N-terminal TEL helix-loop-helix domain is essential for TEL/AML-1B-mediated repression. Thus, the t(12;21) fusion protein dominantly interferes with AML-1B-dependent transcription, suggesting that the inhibition of expression of AML-1 genes is critical for B-cell leukemogenesis.

Signaling by N- and C-terminal sequences of parathyroid hormone-related protein in hippocampal neurons

Parathyroid hormone-related protein (PTHrP) is synthesized in the brain, and a single type of cloned receptor for the N-terminal portion of PTHrP and PTH is present in the central nervous system. Nothing is known about the physiological actions or signaling pathways used by PTHrP in the brain. Using cultured rat hippocampal neurons, we demonstrate that N-terminal PTHrP[1-34] and PTH[1-34] signal via cAMP and cytosolic calcium transients. The cAMP response showed strong acute (< or = 6 h) homologous and heterologous desensitization after preincubation with PTHrP or PTH. In contrast, the acute calcium response did not desensitize after preincubation with PTHrP; in fact, preincubation dramatically recruited additional responsive neurons. Unexpectedly, C-terminal PTHrP[107-139], which does not bind or activate the cloned PTH/PTHrP receptor, signaled in neurons via cytosolic calcium but not cAMP. Although some neurons responded to both PTHrP[1-34] and PTHrP[107-139], others responded only to PTHrP[1-34]. We conclude that certain hippocampal neurons exhibit dual signaling in response to PTHrP[1-34] and that some neurons have a receptor for C-terminal PTHrP that signals only via cytosolic calcium.

A mitochondrial bottleneck hypothesis of Alzheimer's disease

Alzheimer's disease, in its early onset familial form, is known to be a heterogeneous disorder. This suggests that the different degenerative mechanisms, initiated by different genetic causes and ending in the shared phenotype of the disease, should intersect at some point in the degenerative cascade to form a 'bottleneck' from which the pathological features that are common to each of the genetic forms emerge. A growing body of evidence suggests that disturbances of energy metabolism may play a fundamental role in the onset and progression of Alzheimer's disease. In light of this, we propose a 'mitochondrial bottleneck hypothesis', which unifies the various forms of the disease in which different causes lead to the disorder via disturbances of mitochondrial function. The characterization of such a bottleneck would present a unique target for therapeutic intervention because it would be the earliest point in a neurodegenerative cascade shared by all forms of Alzheimer's disease, independent of cause.

A variant Ewing's sarcoma translocation (7;22) fuses the EWS gene to the ETS gene ETV1

Most Ewing's sarcomas or related primitive neuroectodermal tumors have the (11;22)(q24;q12) or less frequently the (21;22)(q22;q12) translocation. These rearrangements fuse the EWS gene on chromosome 22q12 to either the FLI1 or ERG genes, both members of the ETS family of transcription factors. Simple variant chromosomal translocations have been occasionally described in these tumors. We have identified a third Ewing's sarcoma translocation, the t(7;22)(p22;q12), that fuses EWS to the human homologue of the murine ETS gene ER81. This gene, designated ETV1 (for ETS Translocation Variant), is located on chromosome band 7p22. Identical EWS nucleotide sequences found in the majority of EWS-FLI1 and EWS-ERG chimeric transcripts are fused to a portion of ETV1 encoding an ETS domain with sequence specific DNA-binding activity. These findings confirm that the fusion of EWS to different ETS family members can result in a similar tumor phenotype.

A new glibenclamide-insensitive neuroselective hyperpolarizing agent

We describe a novel compound, (-)-N-(2-ethoxyphenyl)-N'-(1,2,3-trimethylpropyl)-2-nitroethene-1, 1-diamine), Bay x9227, that demonstrates dose-dependent hyperpolarizing activity of remarkable potency (EC50 3 picomolar) and selectivity for CNS neurons and clonal neurotypic cells compared to smooth muscle cells. Single cell membrane potential measurements were obtained in physiologic buffer using the fluorescent probe, bisoxonol. Unlike K+ATP-channel activators including its (+)-enantiomer (Hoffman et al., 1993, Biochem. Biophys. Res. Commun. 190(2), 551), this activity was insensitive to glibenclamide antagonism. These data suggest a novel pharmacologic site for effecting neuroselective hyperpolarization.