Integrative genome-wide analysis reveals EIF3A as a key downstream regulator of translational repressor protein Musashi 2 (MSI2)

Musashi 2 (MSI2) is an RNA binding protein (RBP) that regulates asymmetric cell division and cell fate decisions in normal and cancer stem cells. MSI2 appears to repress translation by binding to 3′ untranslated regions (3′UTRs) of mRNA, but the identity of functional targets remains unknown. Here, we used individual nucleotide resolution cross-linking and immunoprecipitation (iCLIP) to identify direct RNA binding partners of MSI2 and integrated these data with polysome profiling to obtain insights into MSI2 function. iCLIP revealed specific MSI2 binding to thousands of mRNAs largely in 3′UTRs, but translational differences were restricted to a small fraction of these transcripts, indicating that MSI2 regulation is not triggered by simple binding. Instead, the functional targets identified here were bound at higher density and contain more ‘UAG’ motifs compared to targets bound nonproductively. To further distinguish direct and indirect targets, MSI2 was acutely depleted. Surprisingly, only 50 transcripts were found to undergo translational induction on acute loss. Using complementary approaches, we determined eukaryotic translation initiation factor 3A (EIF3A) to be an immediate, direct target. We propose that MSI2 downregulation of EIF3A amplifies these effects on translation. Our results also underscore the challenges in defining functional targets of RBPs since mere binding does not imply a discernible functional interaction.

Bioavailability of Oral Hydrocortisone Corrected for Binding Proteins and Measured by LC-MS/MS Using Serum Cortisol and Salivary Cortisone

Context

The assessment absolute bioavailability of oral hydrocortisone is complicated by its saturable binding to cortisol binding globulin (CBG). Previous assessment of bioavailability used a cortisol radioimmunoassay which has cross reactivity with other steroids. Salivary cortisone is a measure of free cortisol and LC-MS/MS is the gold standard method for measuring steroids. We here report the absolute bioavailability of hydrocortisone calculated using serum cortisol and salivary cortisone measured by LC-MS/MS.

Methods

14 healthy male dexamethasone suppressed volunteers were administered 20 mg hydrocortisone either intravenously or orally by tablet. Samples of serum and saliva were taken and measured for cortisol and cortisone by LC-MS/MS. Serum cortisol was corrected for saturable binding using published data and pharmacokinetic parameters derived using the program WinNonlin.

Results

The mean (95% CI) bioavailability of oral hydrocortisone calculated from serum cortisol, unbound serum cortisol and salivary cortisone was 1.00 (0.89-1.14); 0.88 (0.75-1.05); and 0.93 (0.83-1.05), respectively.

Conclusion

The data confirm that, after oral administration, hydrocortisone is completely absorbed. The data derived from serum cortisol corrected for protein binding, and that from salivary cortisone, are similar supporting the concept that salivary cortisone reflects serum free cortisol levels and that salivary cortisone can be used as a non-invasive method for measuring the pharmacokinetics of hydrocortisone.

Preferences for Sexual Symbols in the Genital Stage: A Replication

Freud's theory of sexual symbolism was tested with 61 twelfth grade students (33 females and 28 males). The students indicated their preferences for one figure in each of 15 figure pairs, some being from Cameron, some being new. The results were not consistent with Cameron's (1967) findings that adolescents preferred male phallic symbols. In the present study, genital stage females ( p < .01) and males ( p < .001) preferred female sexual symbols. The results may reflect the breakdown of the masculine-oriented culture during the 1960s and 1970s.

GH safety workshop position paper: a critical appraisal of recombinant human GH therapy in children and adults

Recombinant human GH (rhGH) has been in use for 30 years, and over that time its safety and efficacy in children and adults has been subject to considerable scrutiny. In 2001, a statement from the GH Research Society (GRS) concluded that 'for approved indications, GH is safe'; however, the statement highlighted a number of areas for on-going surveillance of long-term safety, including cancer risk, impact on glucose homeostasis, and use of high dose pharmacological rhGH treatment. Over the intervening years, there have been a number of publications addressing the safety of rhGH with regard to mortality, cancer and cardiovascular risk, and the need for long-term surveillance of the increasing number of adults who were treated with rhGH in childhood. Against this backdrop of interest in safety, the European Society of Paediatric Endocrinology (ESPE), the GRS, and the Pediatric Endocrine Society (PES) convened a meeting to reappraise the safety of rhGH. The ouput of the meeting is a concise position statement.

Relationship between final height and health outcomes in adults with congenital adrenal hyperplasia: United Kingdom congenital adrenal hyperplasia adult study executive (CaHASE)

CONTEXT

Treatment of congenital adrenal hyperplasia (CAH) in childhood focuses on growth and development and adult final height (FH) is a measure of effective treatment. We hypothesized that shorter adults will have more severe underlying disease and worse health outcomes.

METHODS

This was a cross-sectional analysis of 199 adults with CAH. FH and quality of life were expressed as z-scores adjusted for midparental target height or UK population height.

RESULTS

FH correlated inversely with age (men, r = -0.38; women, r = -0.26, P < .01). Men and women had z-scores adjusted for midparental target height of -2 and -1, respectively, and both groups had UK population height z-scores of -1 below the UK population (P < .01). In women, FH was shorter in non-salt-wasting than salt-wasting classic CAH (P < .05) and in moderately affected genotype group B women than either more severely affected groups null and A (P < .01) or the mildest group C (P < .001). Short stature and a higher prevalence of hypertension were observed in classic CAH patients diagnosed late (after 1 y) compared with those diagnosed early and in women treated with glucocorticoid only compared with those treated with both glucocorticoids and mineralocorticoids (P < .05). FH did not associate with insulin sensitivity, lipid profile, adiposity, or quality of life.

CONCLUSIONS

Adult CAH patients remain short, although height prognosis has improved over time. The shortest adults are those diagnosed late with moderate severity CAH and are at increased risk of adult hypertension; we hypothesize that these patients are exposed in childhood to high androgens and/or excessive glucocorticoids with potential programming of hypertension. Another possibility is inadequate mineralocorticoid treatment early in life in the late-diagnosed patient group. Prospective studies are now required to examine these hypotheses.

PIWI proteins and PIWI-interacting RNAs in the soma

The discovery of millions of PIWI-interacting RNAs revealed a fascinating and unanticipated dimension of biology. The PIWI-piRNA pathway has been commonly perceived as germline-specific, even though the somatic function of PIWI proteins was documented when they were first discovered. Recent studies have begun to re-explore this pathway in somatic cells in diverse organisms, particularly lower eukaryotes. These studies have illustrated the multifaceted somatic functions of the pathway not only in transposon silencing but also in genome rearrangement and epigenetic programming, with biological roles in stem-cell function, whole-body regeneration, memory and possibly cancer.

Genetic markers and biomarkers for age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of visual impairment and blindness in the USA. Although the treatment of AMD has evolved to include laser photocoagulation, photodynamic therapy, surgical macular translocation and antiangiogenesis agents, treatment options for advanced AMD are limited. Furthermore, the dry form of AMD, albeit less devastating than the wet form, has even fewer viable treatment options. This review summarizes the various biomarkers of AMD and analyzes whether or not they may one day be exploited to determine risks of disease onset, measure progression of disease or even assess the effects of treatment of AMD. Potential biomarkers are important to identify since some might be utilized to reflect the disease state of a particular patient and to individualize therapy. Although studies have yielded promising results for nutrient and inflammatory biomarkers, these results have been inconsistent. At present, the best available markers of AMD risk are single nucleotide polymorphisms (SNPs). SNPs in complement factor H (CFH) and PLEKHA1/ARMS2/HtrA1 capture a substantial fraction of AMD risk and permit the identification of individuals at high risk of developing AMD.

Glucocorticoid treatment regimen and health outcomes in adults with congenital adrenal hyperplasia

BACKGROUND

Adults with congenital adrenal hyperplasia (CAH) are treated with a wide variety of glucocorticoid treatment regimens.

OBJECTIVE, DESIGN AND METHODS

To test whether drug dose and timing of glucocorticoid treatment regimen impacts on health outcomes. This was a cross-sectional study of 196 adult CAH patients in whom treatment and health outcomes were measured. Glucocorticoid dose was converted to prednisolone dose equivalent (PreDEq) using three published formulae. Associations between the type of glucocorticoid regimen and PreDEq with specific health outcome variables were tested using partial correlation and principal components analysis (PCA).

RESULTS

Patients on dexamethasone had lower androgens and ACTH but greater insulin resistance compared with those receiving hydrocortisone or prednisolone. Dexamethasone dose and once daily administration were associated with insulin resistance. Partial correlation analysis adjusted for age and sex showed PreDEq weakly correlated (r < 0·2) with blood pressure and androstenedione. Mutation severity was associated with increased PreDEq (F(3,141)  = 4·4, P < 0·01). In PCA, 3 PCs were identified that explained 62% of the total variance (r(2) ) in observed variables. Regression analysis (age and sex adjusted) confirmed that PC2, reflecting disease control (androstenedione, 17-hydroxypregesterone and testosterone), and PC3, reflecting blood pressure and mutations (systolic and diastolic blood pressure and mutation severity), related directly to PreDEq (r(2)  = 23%, P < 0·001).

CONCLUSIONS

In adults with congenital adrenal hyperplasia, dexamethasone use was associated with lower androgens but greater insulin resistance, and increasing glucocorticoid dose associated with increased blood pressure, poor disease control and mutation severity.

Reduced appetite and body mass index with delayed puberty in a mother and son: association with a rare novel sequence variant in the leptin gene

INTRODUCTION

Leptin deficiency caused by mutations within the leptin gene (LEP) results in severe early onset obesity, hypogonadism, pubertal delay and immune system abnormalities. Constitutional delay in growth and puberty (CDGP) is a common condition seen in paediatric clinics, in which children present with delayed growth and puberty but usually also have a slim body habitus. We hypothesized that LEP variants may play a role in the phenotype seen in CDGP.

AIM

To screen a group of children with CDGP for pathogenic sequence variants in LEP.

PATIENTS AND METHODS

Denaturing HPLC was used to screen for LEP sequence variants in DNA samples from 78 children with CDGP (predominantly white males) and 112 control subjects. DNA fragments with a WAVE pattern deviant from wild type were directly sequenced. A STAT3 luciferase reporter assay in human embryonic kidney (HEK293) cells transiently transfected with the leptin receptor was used to test activity of mutant leptin.

RESULTS

One child with CDGP was identified to be heterozygous for a novel missense variant (c.68C>G), which results in a proline to arginine substitution (p.P23R). This sequence variant was not identified in any of the other control subjects, but was identified in his mother who shared a similar phenotype of slim body habitus, reduced appetite and pubertal delay (menarche aged 15 years). The leptin variant showed similar stability in serum compared with wild type and did not demonstrate increased activity in an in vitro reporter gene assay.

CONCLUSIONS

This is the first report of a sequence variant within the LEP gene associated with reduced body mass index rather than obesity. We hypothesize that this variant has increased bioactivity in vivo.

The effect of occlusion on the semantics of projective spatial terms: a case study in grounding language in perception

Although data-driven spatial template models provide a practical and cognitively motivated mechanism for characterizing spatial term meaning, the influence of perceptual rather than solely geometric and functional properties has yet to be systematically investigated. In the light of this, in this paper, we investigate the effects of the perceptual phenomenon of object occlusion on the semantics of projective terms. We did this by conducting a study to test whether object occlusion had a noticeable effect on the acceptance values assigned to projective terms with respect to a 2.5-dimensional visual stimulus. Based on the data collected, a regression model was constructed and presented. Subsequent analysis showed that the regression model that included the occlusion factor outperformed an adaptation of Regier & Carlson's well-regarded AVS model for that same spatial configuration.

Peroxisome Proliferator-Activated Receptor Expression in Murine Models and Humans with Age-related Macular Degeneration

Peroxisome proliferator-activated receptors (PPARs) play a role in oxidative stress and VEGF regulation, which are closely related to age-related macular degeneration (AMD). PPAR γ expression and its downstream molecules were examined in fat-1 mice (transgenic mice that convert n-6 to n-3 fatty acids), Ccl2(-/-)/Cx3cr1(-/-) mice (an AMD model), ARPE19 cells (a human retinal pigment epithelial cell line, RPE, a cell type with a critical role in AMD), and human eyes with and without AMD. PPAR α, β, and γ, VEGF and receptors were determined by immunohistochemistry in the mice models, humans, and ARPE19 cells. Transcripts of PPARs, VEGF, MMP-9 and HO-1 were determined by RQ-PCR. PPARs were constitutively expressed in normal neuroretina and RPE of humans and mice. PPAR γ expression was increased in fat-1 and Ccl2(-/-)/Cx3cr1(-/-) mice. VEGF was decreased in fat-1 mice but increased in Ccl2(-/-)/Cx3cr1(-/-) mice. VEGF receptors were stable. VEGF, MMP9 and HO-1 transcript levels were increased in ARPE19 cells under H(2)O(2) - induced oxidative stress. Human AMD retinas exhibited higher PPAR γ. The findings of increased expression of PPAR γ and its downstream proteins (VEGF, MMP9, and HO-1) in H(2)O(2)-treated ARPE19 cells, Ccl2(-/-)/Cx3cr1(-/-) mice, and human AMD eyes, but decreased VEGF in fat-1 mice, suggest that PPAR γ may play a role in AMD.

A high omega-3 fatty acid diet reduces retinal lesions in a murine model of macular degeneration

Age-related macular degeneration (AMD) is one of the leading cause of blindness among the elderly; however, current therapy options are limited. Epidemiological studies have shown that a diet that is high in omega-3 polyunsaturated (n-3) fatty acids can slow disease progression in patients with advanced AMD. In this study, we evaluated the effect of such a diet on the retinas of Ccl2(-/-)/Cx3cr1(-/-) mice, a model that develops AMD-like retinal lesions that include focal deep retinal lesions, abnormal retinal pigment epithelium, photoreceptor degeneration, and A2E accumulation. Ccl2(-/-)/Cx3cr1(-/-) mice that ingested a high n-3 fatty acid diet showed a slower progression of retinal lesions compared with the low n-3 fatty acids group. Some mice that were given high levels of n-3 fatty acids had lesion reversion. We found a shunted arachidonic acid metabolism that resulted in decreased pro-inflammatory derivatives (prostaglandin E(2) and leukotriene B(4)) and an increased anti-inflammatory derivative (prostaglandin D(2)). We also measured lower ocular TNF-alpha and IL-6 transcript levels in the mice fed a diet of high n-3 fatty acids. Our findings in these mice are in line with human studies of AMD risk reduction by long-chain n-3 fatty acids. This murine model provides a useful tool to evaluate therapies that might delay the development of AMD.

The HtrA1 promoter polymorphism, smoking, and age-related macular degeneration in multiple case-control samples

OBJECTIVE

To assess the association and combined effect on the risk of age-related macular degeneration (AMD) by the HtrA1 and complement factor H (CFH) polymorphisms, smoking, and serum cholesterol.

DESIGN

Clinic-based and population-based case control study.

PARTICIPANTS

A total of 805 AMD cases and 921 controls from The Eye Clinic of National Eye Institute, Age-Related Eye Diseases Study, Blue Mountain Eye Study Cohort, and Minnesota Lions Eye Bank.

METHODS

DNA samples were genotyped for polymorphisms of rs11200638 in HtrA1 promoter and rs380390 in CFH. HtrA1 protein in ocular tissue was measured. Interactions of the HtrA1 risk allele with the CFH risk variant, smoking status, and cholesterol were assessed.

MAIN OUTCOME MEASURES

AMD was evaluated by retinal specialists, and AMD subtypes (geographic atrophy and neovascularization) were determined.

RESULTS

Strong associations of the HtrA1 risk allele (A) with AMD were present in all sample sets. A similar magnitude of association was observed for central geographic atrophy and neovascular AMD. The combination of the HtrA1 and CFH risk alleles increased AMD susceptibility, as did the combination of the HtrA1 risk allele with smoking. No combined effect of HtrA1 risk allele and cholesterol level was found. Enhanced expression of HtrA1 protein was detected in retina with AMD.

CONCLUSIONS

Findings from multiple samples support an AMD genetic variant harbored within HtrA1. The risk of advanced AMD increased when the presence of risk alleles from HtrA1 was combined with either CFH risk alleles or history of smoking.

Free triiodothyronine has a distinct circadian rhythm that is delayed but parallels thyrotropin levels

CONTEXT

TSH is known to have a circadian rhythm, but the relationship between this and any rhythm in T(4) and T(3) has not been clearly demonstrated.

OBJECTIVE

With a view to optimizing thyroid hormone replacement therapy, we have used modern assays for free T(4) (FT4) and free T(3) (FT3) to investigate circadian rhythmicity.

SETTING

The study was performed at a university hospital.

DESIGN AND SUBJECTS

This was a cross-sectional study in 33 healthy individuals with 24-h blood sampling (TSH in 33 and FT4 and FT3 in 29 individuals) and cosinor analysis.

RESULTS

Of the individuals, 100% showed a sinusoidal signal in TSH, for FT4 76%, and for FT3 86% (P < 0.05). For FT4 and FT3, the amplitude was low. For TSH the acrophase occurred at a clock time of 0240 h, and for FT3 approximately 90 minutes later at 0404 h. The group cosinor model predicts that TSH hormone levels remain above the mesor between 2020 and 0820 h, and for FT3 from 2200-1000 h. Cross correlation of FT3 with TSH showed that the peak correlation occurred with a delay of 0.5-2.5 h. When time-adjusted profiles of TSH and FT3 were compared, there was a strong correlation between FT3 and TSH levels (rho = 0.80; P < 0.0001). In contrast, cross correlation revealed no temporal relationship between FT4 and TSH.

CONCLUSIONS

FT3 shows a circadian rhythm with a periodicity that lags behind TSH, suggesting that the periodic rhythm of FT3 is due to the proportion of T(3) derived from the thyroid. Optimizing thyroid hormone replacement may need to take these rhythms into account.

Ccl2/Cx3cr1-deficient mice: an animal model for age-related macular degeneration

BACKGROUND/AIMS

Senescent Ccl2-/- mice develop cardinal features of human age-related macular degeneration (AMD). Loss-of-function single-nucleotide polymorphisms within CX3CR1 are associated with AMD.

METHODS

We generated Ccl2-/-/Cx3cr1-/- [double-knockout (DKO)] mice and evaluated the eyes using fundoscopy routine histology, immunochemistry, biochemistry and proteomics.

RESULTS

At 6 weeks old, all DKO mice developed AMD-like retinal lesions such as abnormal retinal pigment epithelium cells, drusen, photoreceptor atrophy and choroidal neovascularization, which progressed with age and reversed with high omega-3 long-chain polyunsaturated fatty acid diet. N-retinylidene-N-retinylethanolamine (A2E), a major lipofuscin fluorophore, illustrated by an emission peak at approximately 600 nm, was significantly higher in DKO retinal pigment epithelium. Decreased ERp29 was found in the retina of DKO mice.

CONCLUSION

A broad spectrum of AMD pathologies with early onset and high penetrance in these mice implicate certain chemokines, A2E and endoplasmic reticulum proteins in AMD pathogenesis.

Immunological protein expression profile in Ccl2/Cx3cr1 deficient mice with lesions similar to age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of blindness in the United States. Ccl2 knock-out (KO) mice sporadically develop the cardinal features of AMD in their senescent stage. Humans bearing a loss of function variant or single nucleotide polymorphism (SNP) in CX3CR1 are at increased risk of developing AMD. We recently developed Ccl2(-/-)/Cx3cr1(-/-) mice, which consistently develop retinal degeneration with many AMD features. Since there is strong evidence for an immunological role in AMD pathogenesis, we examined ocular immune protein expression levels in Ccl2(-/-)/Cx3cr1(-/-), Ccl2(-/-), Cx3cr1(-/-), and age-matched wild-type (WT) mice. Immunohistochemistry revealed increased complement C3d in Bruch's membrane, retinal pigment epithelium (RPE), choroidal capillaries, and particularly drusen of the Ccl2(-/-)/Cx3cr1(-/-) mice relative to the WT controls. No change was detected in single KO mice. Real-time RT-PCR revealed a 2.5-fold increase in C3 expression in the Ccl2(-/-)/Cx3cr1(-/-). While the retinas of four month old WT and Ccl2(-/-) showed minimal immunoreactivity for markers of macrophages and microglia, infiltrates of these mononuclear phagocytic cells were detected in the Ccl2(-/-)/Cx3cr1(-/-)retinal lesions and a few foci in the Cx3cr1(-/-) retina. The Ccl2(-/-)/Cx3cr1(-/-) had reduced toll-like receptor 4 (TLR4) expression in the RPE. Following LPS injection, the Ccl2(-/-)/Cx3cr1(-/-) had significantly reduced endotoxin-induced uveitis scores and showed a diminished increase in Tlr4 mRNA expression. No changes in TLR4 expression were detected in either single KO. Autoantibodies against the retina and photoreceptors were also detected in the Ccl2(-/-)/Cx3cr1(-/-) serum. Real-time RT-PCR revealed significant increases in Ccl5 transcript in the Ccl2(-/-)/Cx3cr1(-/-) relative to the WT. These results suggest that innate immunity and possibly adaptive immunity play an important role in Ccl2(-/-)/Cx3cr1(-/-) retinal degeneration. Moreover, since human AMD patients show similar immunopathological profiles, these results support the Ccl2(-/-)/Cx3cr1(-/-) as a suitable model for human AMD.

Murine ccl2/cx3cr1 deficiency results in retinal lesions mimicking human age-related macular degeneration

PURPOSE

Senescent Ccl2(-/-) mice are reported to develop cardinal features of human age-related macular degeneration (AMD). Loss-of-function single-nucleotide polymorphisms within CX3CR1 are also found to be associated with AMD. The authors generated Ccl2(-/-)/Cx3cr1(-/-) mice to establish a more characteristic and reproducible AMD model.

METHODS

Single Ccl2- and Cx3cr1-deficient mice were crossbred to obtain Ccl2(-/-)/Cx3cr1(-/-) mice. Funduscopy, histopathology, retinal A2E quantification, proteomics, RT-PCR gene expression assay, immunochemistry, and Western blotting were used to examine the retina and to evaluate gene expression within the retinal tissue.

RESULTS

By 6 weeks of age, all Ccl2(-/-)/Cx3cr1(-/-) mice developed AMD-like retinal lesions, including drusen, retinal pigment epithelium alteration, and photoreceptor degeneration. Furthermore, choroidal neovascularization occurred in 15% of the mice. These degenerative lesions progressed with age. A2E, a major lipofuscin fluorophore that accumulated during AMD progression, was significantly higher in the Ccl2(-/-)/Cx3cr1(-/-) retina than in the wild-type retina. Complement cofactor was higher in the Ccl2(-/-)/Cx3cr1(-/-) RPE. Proteomics data indicated that four proteins were differentially expressed in Ccl2(-/-)/Cx3cr1(-/-) retina compared with control. One of these proteins, ERp29, an endoplasmic reticulum protein, functions as an escort chaperone and in protein folding.

CONCLUSIONS

The authors concluded that Ccl2(-/-)/Cx3cr1(-/-) mice develop a broad spectrum of AMD abnormalities with early onset and high penetrance. These observations implicate certain chemokines and endoplasmic reticulum proteins in AMD pathogenesis. Similar to the mechanism of neurodegeneration caused by dysfunction of endoplasmic reticulum proteins, decreased chaperoning may cause misfolded protein accumulation, leading to drusen formation and retinal degeneration.

The LOC387715 polymorphism, inflammatory markers, smoking, and age-related macular degeneration. A population-based case-control study

OBJECTIVE

To assess combined effects on the risk of age-related macular degeneration (AMD) by the LOC387715 polymorphism, smoking, and inflammatory or hemostatic factors.

DESIGN

Population-based case-control study.

PARTICIPANTS

Two hundred seventy-eight AMD cases (224 early, 54 late) and 557 controls matched for age, gender, and smoking, drawn from the Blue Mountains Eye Study cohort.

METHODS

Subjects were genotyped for the LOC387715 Ala69Ser polymorphism (rs# 10490924). Smoking was self-reported. Serum high-sensitivity C-reactive protein (CRP), interleukin 6 (IL-6), soluble intercellular adhesion molecule 1 (sICAM-1), fibrinogen, homocysteine, plasminogen activator inhibitor 1 (PAI-1), von Willebrand factor, and white cell count (WCC) were measured. Combined effects of this genetic variant plus any of these study factors on AMD risk were assessed using logistic regression models, adjusted for age and smoking. We defined interaction if the influence of 2 factors departed from the multiplicative scale, confirmed by a statistically significant interaction term. Otherwise, the combined effect was used.

MAIN OUTCOME MEASURES

Age-related macular degeneration was graded using the Wisconsin grading system.

RESULTS

Combined effects on the likelihood of early or late AMD were demonstrated for the LOC387715 Ala69Ser G/T and T/T genotypes with the markers high-sensitivity CRP (odds ratios [ORs], 1.2 for the highest tertile alone, 1.6 for G/T and T/T genotypes alone, and 2.2 for both G/T and T/T genotypes plus the highest tertile, compared with the G/G genotype with the 2 lower tertiles), IL-6 (corresponding ORs, 1.1, 1.6, and 2.2), sICAM-1 (ORs, 1.0, 1.5, and 2.3, respectively), and PAI-1 (ORs, 1.3, 1.7, and 2.3, respectively), but not with WCC, fibrinogen, homocysteine, and von Willebrand factor. Findings were similar for early and late AMD separately. Current smokers with G/T and T/T genotypes had strong combined effects on late AMD risk compared with those who never smoked or past smokers with the G/G genotype (ORs, 1.2 for current smokers alone, 1.8 for G/T and T/T genotypes alone, and 6.1 for current smokers plus G/T and T/T genotypes).

CONCLUSIONS

We found no significant interaction but combined effects for the LOC387715 genotypes with 3 inflammatory markers and PAI-1 on the risk of early or late AMD, and with current smoking on the risk of late AMD.

The LOC387715 polymorphism and age-related macular degeneration: replication in three case-control samples

PURPOSE

Age-related macular degeneration (AMD) is a multifactorial blinding disease in the elderly. LOC387715 harbors a single-nucleotide polymorphism that has an association with AMD. This study was conducted to confirm the association between LOC387715 and AMD and to refine estimates of the impact of this gene variation in using samples from three studies: an Australian population-based study and two U.S. clinic-based case-control studies.

METHODS

Cases and controls were collected from a National Eye Institute (NEI) clinical protocol (n = 240), the Age-Related Eye Disease Study (AREDS; n = 488), and the Blue Mountains Eye Study (BMES; n = 851). After DNA extraction, subjects were genotyped for the LOC387715 Ala69Ser polymorphism (rs10490924).

RESULTS

The combined NEI and AREDS samples yielded odds ratios (ORs) of 2.61 (95% CI 1.89-3.61, P = 1.42 x 10(-9)) and 8.59 (95% CI 4.49-16.5, P = 3.56 x 10(-13)) for the heterozygous and homozygous risk alleles, respectively. The corresponding odds ratios in the BMES sample were 1.69 (95% CI: 1.25-2.28, P = 0.0007) and 2.20 (95% CI: 1.05-4.62, P = 0.038) for the heterozygous and homozygous groups. Neither set of samples showed statistically significant interaction with smoking, although there appeared to be a trend of interaction between smoking and LOC387715 for risk of advanced AMD.

CONCLUSIONS

Although these data from three case-control samples support an AMD genetic risk marker harbored within LOC387715, the nested case-control data from the population-based BMES samples showed lower estimates than from the clinic-based samples. This may be because the BMES samples consisted of largely early AMD cases while the clinic-based AMD samples consisted exclusively of advanced cases.

Combining growth hormone releasing hormone-arginine and synacthen testing diminishes the cortisol response

OBJECTIVES

The GHRH/arginine test and short synacthen test (SST) have been validated as safe alternatives to the insulin tolerance test for the assessment of the GH reserve and hypothalamic-pituitary-adrenal axis integrity, respectively. However, these two tests are usually performed separately. The objective was to see whether the synacthen and GHRH/arginine tests could be combined to save time and blood samples and minimize inconvenience to patients.

PATIENTS/METHODS

Twenty-four consecutive patients with adult onset pituitary disease requiring pituitary function testing were randomized to receive sequentially and in random order a SST, a GHRH/arginine test, and a combined SST and GHRH/arginine test on three different visits separated by at least 1 wk.

RESULTS

There was no difference in basal cortisol or ACTH values for the SST done alone or during the combined test. However, when GHRH/arginine was given with synacthen, patients had a lower peak cortisol response with a mean difference of 116 nmol/liter (95% confidence interval, 52.54 to 179.37; P < 0.001), and one patient with a normal response on the SST had a subnormal cortisol response in the combined test. Similar lower peak cortisol responses were observed in males and females with combined test. The difference between the peak cortisol responses showed no significant correlation with age (r = 0.123; P = 0.58) or with the body mass index (r = -0.376; P = 0.09). There was no difference in GH measurements between the GHRH/arginine test done alone or in combination with the SST.

CONCLUSIONS

Combining the SST and GHRH/arginine test results in a lower cortisol response to synacthen. For this reason, the combined test cannot be recommended to assess the integrity of cortisol and GH reserve using current diagnostic criteria.

Human HtrA1 in the archived eyes with age-related macular degeneration

PURPOSE

HtrA1 belongs to the high temperature requirement factor A family of serine proteases, which are involved in protein quality control and cell fate. A single-nucleotide polymorphism (SNP), rs11200638, in the promoter of HtrA1 at chromosome 10q26 is reported as a likely causal variant for age-related macular degeneration (AMD). The SNP is located in the regulatory region and increases production of HtrA1 protein. This study investigates HtrA1 expression and SNP genotypes in archived ocular slides with AMD.

METHODS

Macular, nonretinal, and peripheral retinal cells were microdissected from archived slides from 57 eyes with AMD and 16 age-matched, non-AMD controls. HtrA1 rs11200638 SNP genotyping was performed using polymerase chain reaction (PCR) and restriction fragment length polymorphism analysis. HtrA1 transcripts were measured using real-time reverse transcriptase-PCR. HtrA1 protein expression was evaluated using avidin-biotin complex immunohistochemistry.

RESULTS

HtrA1 (G/A) SNP was successfully genotyped in 52 AMD cases and 13 non-AMD subjects. The frequencies of the risk allele (A) were 55 of 104 (52.9%) and 8 of 26 (30.8%) in AMD and control groups, respectively. HtrA1 mRNA was detected in normal peripheral and macular retinas, higher in the periphery than maculae. HtrA1 mRNA was much higher in the macula and a lot lower in the periphery of the AMD eyes as compared to control eyes. HtrA1 protein was expressed in normal retinal vascular endothelia and retinal pigment epithelia. Intense immunoreaction against HtrA1 was found in AMD lesions, slightly more in wet than dry AMD lesions.

CONCLUSION

This study successfully analyzes HtrA1 SNP and transcript expression in microdissected cells from archived paraffin fixed slides. Up-regulation of HtrA1 is detected in the macular lesions of AMD eyes. The data further suggest that rs11200638 in HtrA1 promoter is associated with AMD development.

Circadian hydrocortisone infusions in patients with adrenal insufficiency and congenital adrenal hyperplasia

OBJECTIVE

Conventional hydrocortisone therapy in adrenal insufficiency cannot provide physiological replacement. We have explored the potential of circadian delivery of hydrocortisone as proof of concept for such therapy delivered in modified-release tablet formulation.

METHODS

We investigated whether the circadian intravenous infusion of hydrocortisone could improve control of ACTH and androgen levels. Two healthy subjects, two patients with Addison's disease and two patients with congenital adrenal hyperplasia (CAH) were studied.

RESULTS

In patients on thrice daily oral hydrocortisone, peak serum cortisol levels were higher than in normal subjects and overnight levels were very low. Patients had very high plasma ACTH levels before their morning dose of hydrocortisone, both at the beginning and at the end of their conventional oral therapy: mean +/- SEM 311.8 +/- 123.2 and 311.2 +/- 85.4 ng/l, respectively. In the patients with CAH, serum 17-hydroxyprogesterone levels were also elevated: 550 and 642 nmol/l at the beginning and 550 and 777 nmol/l at the end of conventional treatment, respectively. The overall 24-h mean cortisol levels were similar for conventional oral hydrocortisone and the circadian infusion. At 0700 h, ACTH levels were much higher on conventional treatment than after circadian infusion: mean +/- SEM 311.2 +/- 85.4 vs. 70.5 +/- 45.0 ng/l, respectively (P < 0.05). The same pattern was observed in 17-hydroxyprogesterone levels, which were 550 and 777 nmol/l after conventional treatment and 3 and 64 nmol/l after circadian infusion.

CONCLUSIONS

In patients with poor biochemical control of Addison's disease and CAH, a 24-h circadian infusion of hydrocortisone can decrease morning ACTH and 17-hydroxyprogesterone levels to near normal.

Synergic effect of polymorphisms in ERCC6 5' flanking region and complement factor H on age-related macular degeneration predisposition

This study investigates age-related macular degeneration (AMD) genetic risk factors through identification of a functional single-nucleotide polymorphism (SNP) and its disease association. We chose ERCC6 because of its roles in the aging process, DNA repair, and ocular degeneration from the gene disruption. Bioinformatics indicated a putative binding-element alteration on the sequence containing C-6530>G SNP in the 5' flanking region of ERCC6 from Sp1 on the C allele to SP1, GATA-1, and OCT-1 on the G allele. Electrophoretic mobility shift assays displayed distinctive C and G allele-binding patterns to nuclear proteins. Luciferase expression was higher in the vector construct containing the G allele than that containing the C allele. A cohort of 460 advanced AMD cases and 269 age-matched controls was examined along with pathologically diagnosed 57 AMD and 18 age-matched non-AMD archived cases. ERCC6 C-6530>G was associated with AMD susceptibility, both independently and through interaction with an SNP (rs380390) in the complement factor H (CFH) intron reported to be highly associated with AMD. A disease odds ratio of 23 was conferred by homozygozity for risk alleles at both ERCC6 and CFH compared with homozygozity for nonrisk alleles. Enhanced ERCC6 expression was observed in lymphocytes from healthy donors bearing ERCC6 C-6530>G alleles. Intense immunostaining of ERCC6 was also found in AMD eyes from ERCC6 C-6530>G carriers. The strong AMD predisposition conferred by the ERCC6 and CFH SNPs may result from biological epistasis, because ERCC6 functions in universal transcription as a component of RNA pol I transcription complex.

High incidence of late effects found in Hodgkin's lymphoma survivors, following recall for breast cancer screening

Assessment of late effects in a cohort of female Hodgkin's lymphoma patients treated with mantle radiotherapy, identified from the DoH breast cancer screening recall showed high mortality and frequent undiagnosed abnormalities in tissues affected by radiotherapy. With increasing age, this patient group may suffer premature cardiac and respiratory morbidity.

Cholinergic regulation of the central nucleus of the amygdala in rats: Effects of local microinjections of cholinomimetics and cholinergic antagonists on arousal and sleep

The amygdala has emerged as an important forebrain modulator of arousal. Acetylcholine plays a role in the regulation of sleep and wakefulness, particularly rapid eye movement sleep (REM). The major cholinergic input to the amygdala comes from the basal forebrain, a region primarily linked to wakefulness. We examined sleep and the encephalogram for 8 h following bilateral microinjections into the central nucleus of the amygdala (CNA) of the cholinergic agonist, carbachol (CARB(L): 0.3 microg; CARB(H): 3.0 microg), the acetylcholinesterase inhibitor, neostigmine (NEO(L): 0.3 microg; NEO(H): 3.0 microg), the muscarinic antagonist, scopolamine (SCO(L): 0.3 microg; SCO(H): 1.0 microg), the nicotinic antagonist, mecamylamine (MEC(L): 0.3 microg; MEC(H): 1.0 microg) and saline (SAL, 0.2 microl) alone. Both doses of CARB and NEO significantly reduced REM, but did not significantly alter non-rapid eye movement sleep (NREM). Both doses of SCO significantly increased NREM, and SCO(H) also produced an initial increase in REM followed by a significant decrease. CARB(H) and NEO(H) decreased REM electroencephalogram (EEG) power in the 5.5-10 Hz band, and NEO(L) and NEO(H) decreased NREM EEG power in the 0.5-5.0 Hz band. CARB(L) decreased waking EEG power in the 0.5-5.0 Hz band, and NEO(H) decreased waking EEG power in the 5.0-10.0 Hz band. Both doses of SCO significantly increased waking EEG power in the 5.5-10.0 Hz band. Compared with SAL, MEC did not significantly alter sleep or EEG power. The reduction of REM by CARB and NEO and the alteration of sleep by SCO indicate that cholinergic regulation of the amygdala is involved in the control of arousal in rodents. In contrast, CARB microinjections into CNA increase REM in cats, though the reasons for the species difference are not known. The results are discussed in the context of anatomical inputs and species differences in the cholinergic regulation of CNA.

A comparison of the metabolism of eighteen-carbon 13C-unsaturated fatty acids in healthy women

Altered use of different dietary fatty acids may contribute to several chronic diseases, including obesity, noninsulin-dependent diabetes mellitus, and cardiovascular disease. However, few comparative data are available to support this link, so the goal of the present study was to compare the metabolism of [(13)C]oleate, [(13)C]alpha-linolenate, [(13)C]elaidate, and [(13)C]linoleate through oxidation and incorporation into plasma lipid fractions and adipose tissue. Each tracer was given as a single oral bolus to six healthy women. Samples were collected over 8 days, and (13)C was analyzed using isotope ratio mass spectrometry. At 9 h postdose, cumulative oxidation was similar for [(13)C]elaidate, [(13)C]oleate, and [(13)C]alpha-linolenate (19 +/- 1%, 20 +/- 4%, and 19 +/- 3% dose, respectively). Significantly lower oxidation of [(13)C]linoleate (12 +/- 4% dose; P < 0.05) was accompanied by its higher incorporation into plasma phospholipids and cholesteryl esters. Abdominal adipose tissue was enriched with [(13)C]alpha-linolenate, [(13)C]elaidate, or [(13)C]linoleate within 6 h. The percentage linoleate in plasma phospholipids correlated positively with [(13)C]linoleate and [(13)C]elaidate oxidation, indicating a potential role of background diet. Conversion of [(13)C]linoleate and [(13)C]alpha-linolenate to longer chain polyunsaturates was a quantitatively minor route of utilization.

Prolactin microinjections into the amygdalar central nucleus lead to decreased NREM sleep

Prolactin administered systemically, intracerebroventricularly or locally into the lateral hypothalamus enhances rapid eye movement sleep (REM) when given diurnally and decreases REM when given nocturnally. The amygdala is being recognized as an important modulator of behavioral state, and the central nucleus of the amygdala (CNA) has a high concentration of prolactin fibers and receptors. We microinjected prolactin (10, 100, 250 ng/0.2 microliter saline) or saline alone into CNA of rats and measured the effect on behavioral state. Prolactin produced a dose-dependent decrease in non-REM (NREM), with the effect becoming significant at the high (250 ng) dose. REM was not significantly affected at any dosage. The results indicate a role for prolactin in CNA in the control of NREM. The results are discussed in terms of the amygdala having a broad role in the regulation of behavioral state.

Central administration of a 5-HT2 receptor agonist and antagonist: lack of effect on rapid eye movement sleep and pgo waves

Serotonin (5-HT) has a role in regulating behavioral state and controlling the production of ponto-geniculo-occipital (PGO) waves, though the exact mechanism of action is not known. The most prevailing explanation is that 5-HT exerts its influence on behavioral state and PGO waves by inhibiting and disinhibiting cholinergic cells in the pedunculopontine tegmentum (PPT) and laterodorsal tegmentum (LDT), which have been implicated in their generation. Recent work in rats has demonstrated 5-HT2 receptors on most cholinergic cells in PPT/LDT. We microinfused the relatively specific 5-HT2 agonist, DOI (1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane), the relatively specific 5-HT2 antagonist, ketanserin, and the nonspecific 5-HT antagonist, methysergide, locally into the peribrachial region of PPT in cats and monitored behavioral state and PGO waves. Neither drug significantly affected behavioral state or PGO wave activity. These results suggest that 5-HT2 receptors associated with cholinergic cells are minimally involved in the control of behavioral state and, together with the recent findings of others, suggest that 5-HT may not modulate PGO wave generation via direct action on cholinergic neurons in PPT/LDT, a departure from the long-held but minimally-tested view.

High-dose leptin activates human leukocytes via receptor expression on monocytes

Leptin is capable of modulating the immune response. Proinflammatory cytokines induce leptin production, and we now demonstrate that leptin can directly activate the inflammatory response. RNA expression for the leptin receptor (Ob-R) was detectable in human PBMCs. Ob-R expression was examined at the protein level by whole blood flow cytometry using an anti-human Ob-R mAb 9F8. The percentage of cells expressing leptin receptor was 25 +/- 5% for monocytes, 12 +/- 4% for neutrophils, and 5 +/- 1% for lymphocytes (only B lymphocytes). Incubation of resting PBMCs with leptin induced rapid expression of TNF-alpha and IL-6 mRNA and a dose-dependent production of TNF-alpha and IL-6 by monocytes. Incubation of resting PBMCs with high-dose leptin (250 ng/ml, 3-5 days) induced proliferation of resting cultured PBMCs and their secretion of TNF-alpha (5-fold), IL-6 (19-fold), and IFN-gamma (2.5-fold), but had no effect on IL-4 secretion. The effect of leptin was distinct from, and additive to, that seen after exposure to endotoxin or activation by the mixed lymphocyte reaction. In conclusion, Ob-R is expressed on human circulating leukocytes, predominantly on monocytes. At high doses, leptin induces proinflammatory cytokine production by resting human PBMCs and augments the release of these cytokines from activated PBMCs in a pattern compatible with the induction of Th1 cytokines. These results demonstrate that leptin has a direct effect on the generation of an inflammatory response. This is of relevance when considering leptin therapy and may partly explain the relationship among leptin, proinflammatory cytokines, insulin resistance, and obesity.

Generation of human soluble leptin receptor by proteolytic cleavage of membrane-anchored receptors

The leptin receptor (ObR) exists in multiple isoforms. In rodents, a soluble isoform is generated by alternative splicing; but in humans, there is no mRNA encoding soluble receptor (leptin binding protein). We investigated the hypothesis that human leptin binding protein can be generated by proteolytic cleavage of membrane-anchored leptin receptors (ObRb and ObRa). Leptin binding protein of similar size to that previously detected in human serum was detected by HPLC in medium of cells transfected with ObRa. ObRa exhibited higher expression at the cell surface than ObRb and generated greater levels of leptin binding protein. Ligand-mediated immunofunctional and immunofluorometric assays revealed that the leptin binding protein in medium bound both leptin and an ObR-specific antibody and that the level of leptin binding protein correlated with receptor expression at the cell surface. Phorbol 12-myristate-13-acetate and N-ethylmaleimide increased the accumulation of leptin binding protein, an indication that the production of leptin binding protein was up-regulated by PKC and sulfhydryl group activation. The protease inhibitors, TNFalpha protease inhibitor 1 and Immunex compound 2, could inhibit the production of leptin binding protein, indicating that the enzyme responsible for leptin binding protein cleavage belongs to the metalloprotease family. In conclusion, human leptin binding protein is generated by proteolytic cleavage of membrane-anchored leptin receptor by a metalloprotease.

Is there a medical need to explore the clinical use of insulin-like growth factor I?

Cloning of the insulin-like growth factor I (IGF-I) gene led to the development in 1987 of recombinant IGF-I available for clinical use. Trials were started targeting endocrine, metabolic and neurological disorders, and beneficial results have been demonstrated in IGF-I deficiency states caused by IGF-I gene deletion and growth hormone (GH) receptor deficiency, type 1 and type 2 diabetes mellitus, and severe insulin resistance syndromes. Results of equivocal benefit have also been reported in osteoporosis and amyotrophic lateral sclerosis. Recent encouraging data using the IGF-I-IGF-binding protein 3 (IGFBP-3) complex in diabetes mellitus suggest that this preparation may eventually replace recombinant free IGF-I. The lack of an established therapeutic indication for IGF-I has resulted in its supplies being severely limited. It will probably be decided during the next decade whether use of IGF-I or the IGF-I-IGFBP-3 complex becomes firmly established as an accepted endocrine therapy.

A single nucleotide polymorphism (SNP) in the leptin receptor is associated with BMI, fat mass and leptin levels in postmenopausal Caucasian women

The human leptin (obese) receptor gene contains a number of single nucleotide polymorphisms, including GLN223ARG, which changes an amino acid on the extracellular region common to all isoforms of the receptor. Here, we demonstrate that, in postmenopausal Caucasian women, genotypes at that locus are associated with differences in body mass index (BMI), fat mass and serum leptin levels. Measurement of serum leptin-binding activity indicates that this may reflect changed receptor function associated with genotype. These observations indicate that functional variations in the leptin receptor gene are important factors in the regulation of adiposity and BMI.

Differential expression of suppressors of cytokine signalling genes in response to nutrition and growth hormone in the septic rat

GH treatment during critical illness and sepsis may increase mortality. A family of negative regulators of cytokine signalling, the suppressors of cytokine signalling (SOCS), have been characterised. SOCS provide a mechanism for cross-talk between the cytokine receptors, including GH. Here, we have investigated the impact of nutrition and GH treatment on GH receptor, SOCS1, SOCS-2, SOCS-3 and cytokine-inducible SH2-containing protein (CIS) hepatic mRNA expression in a rat model of sepsis, caecal ligation and puncture (CLP). Four groups of rats were studied: control (food given ad libitum, n=7), CLP only (n=8), CLP and total parenteral nutrition (TPN) (n=9), and CLP, TPN and GH (n=10). CLP rats underwent surgery and 18 h later received saline or TPN or TPN+GH for 6 h before they were killed. Serum IGF-I levels were lower in all CLP groups (P<0.001). The combination of TPN and GH treatment increased IGF-I levels compared with the saline-treated CLP rats (P<0.01), but IGF-I levels remained lower than control animals (P<0.001). GH receptor and GH-binding protein expression in liver was reduced in animals subjected to CLP and was unaffected by nutrition or GH treatment. Hepatic SOCS-1 was detectable in normal rats, induced in all CLP animals but was unaffected by nutrition and GH. Hepatic SOCS-2 expression was difficult to detect in normal and CLP rats but was greatly induced in CLP rats treated with GH. Hepatic SOCS-3 expression was only just detectable in the control group but was elevated in all CLP groups and unaffected by nutrition and GH. Hepatic CIS expression was difficult to detect in normal rats, was not induced by CLP but was induced by both nutrition and GH. In conclusion, CLP induced low IGF-I levels associated with increased expression of SOCS-1 and SOCS-3, both of which are known to inhibit GH receptor signalling. GH induced SOCS-2 and CIS in the CLP rat despite resistance with respect to IGF-I generation, and parenteral feeding induced CIS in the CLP rat. Thus, there is potential for a complex interaction between GH and cytokine signalling at the level of SOCS expression whereby the inflammatory response may alter GH signalling and GH may influence the inflammatory response.

Influence of fear conditioning on elicited ponto-geniculo-occipital waves and rapid eye movement sleep

The amygdala plays a central role in fear conditioning, a model of anticipatory anxiety. It has massive projections to brainstem regions involved in rapid eye movement sleep (REM) and ponto-geniculo-occipital (PGO) wave generation. PGO waves occur spontaneously in REM or in response to stimuli. Electrical stimulation of the central nucleus of the amygdala enhances spontaneous PGO wave activity during REM and the amplitude of both the acoustic startle response and the elicited PGO wave (PGOE), a neural marker of alerting. This study examined the effects of fear conditioning on REM and on PGOE. On conditioning days, the number of REM episodes, the average REM duration and the REM percentage were decreased while REM latency was increased. The presentation of auditory stimuli in the presence of a light conditioned stimulus produced PGOE of greater amplitudes. The results suggest that fear, most likely involving the amygdala, can influence REM and brainstem alerting mechanisms.