Lack of Association between CD33 rs3865444 and Amyotrophic Lateral Sclerosis: A Case-Control Study

BACKGROUND

Microglial activation is considered to assume a role in the pathogenesis of Amyotrophic Lateral Sclerosis (ALS). To date, the relationship between ALS and the rs3865444 polymorphism of the cluster of differentiation 33 (CD33) has not been explored. The current report aimed to investigate the potential connection between CD33 rs3865444 and ALS.

METHODS

Patients diagnosed with sporadic ALS according to the revised El Escorial criteria, as well as age and sex matched community controls, were enrolled. Two evenly numbered, age and sex matched groups of 155 participants each were genotyped.

RESULTS

No association was found between rs3865444 and ALS [log-additive odds ratio (OR) = 0.83 (0.57, 1.22), over-dominant OR = 0.86 (0.55, 1.36), recessive OR = 0.73 (0.25, 2.17), dominant OR = 0.82 (0.52, 1.29), co-dominant OR1 = 0.68 (0.23, 2.05) and co-dominant OR2 = 0.84 (0.53, 1.33)]. Moreover, no relationship was established between rs3865444 and the age of ALS onset based on both unadjusted and sex adjusted Cox-proportional hazards models. Finally, no association between rs3865444 and ALS was found in subgroup analyses based on the site of ALS onset (bulbar or spinal) and sex.

CONCLUSIONS

The current analysis is the first to report that rs3865444 is not linked to ALS. Larger multi-racial studies are required to confirm these findings.

Deciphering the Role of the rs2651899, rs10166942, and rs11172113 Polymorphisms in Migraine: A Meta-Analysis

The genetic basis of migraine is rather complex. The rs2651899 in the PR/SET domain 16 (PRDM16) gene, the rs10166942 near the transient receptor potential cation channel subfamily M member 8 (TRPM8) gene, and the rs11172113 in the LDL receptor-related protein 1 (LRP1) gene, have been associated with migraine in a genome-wide association study (GWAS). However, data from subsequent studies examining the role of these variants and their relationship with migraine remain inconclusive. The aim of the present study was to meta-analyze the published data assessing the role of these polymorphisms in migraine, migraine with aura (MA), and migraine without aura (MO). We performed a search in the PubMed, Scopus, Web of Science, and Public Health Genomics and Precision Health Knowledge Base (v7.7) databases. In total, eight, six, and six studies were included in the quantitative analysis, for the rs2651899, rs10166942, and rs11172113, respectively. Cochran’s Q and I2 tests were used to calculate the heterogeneity. The random effects (RE) model was applied when high heterogeneity was observed; otherwise, the fixed effects (FE) model was applied. The odds ratios (ORs) and the respective 95% confidence intervals (CIs) were calculated to estimate the effect of each variant on migraine. Funnel plots were created to graphically assess publication bias. A significant association was revealed for the CC genotype of the rs2651899, with the overall migraine group (RE model OR: 1.32; 95% CI: 1.02−1.73; p-value = 0.04) and the MA subgroup (FE model OR: 1.40; 95% CI: 1.12−1.74; p-value = 0.003). The rs10166942 CT genotype was associated with increased migraine risk (FE model OR: 1.36; 95% CI: 1.18−1.57; p-value < 0.0001) and increased MO risk (FE model OR: 1.41; 95% CI: 1.17−1.69; p-value = 0.0003). No association was detected for the rs11172113. The rs2651899 and the rs10166942 have an effect on migraine. Larger studies are needed to dissect the role of these variants in migraine.

Myelin-associated oligodendrocyte basic protein rs616147 polymorphism as a risk factor for Parkinson's disease

BACKGROUND

The rs616147 polymorphism of the myelin-associated oligodendrocyte basic protein (MOBP) gene locus has been associated with amyotrophic lateral sclerosis (ALS). ALS and Parkinson's disease (PD) are two common neurodegenerative disorders that share features regarding their etiology, pathophysiology, and genetic backgrounds. While the MOBP rs616147 polymorphism has been associated with ALS, little is known about its role in PD.

OBJECTIVE

To assess the role of MOBP rs616147 on PD risk.

METHODS

This case-control comparison study consists of 358 PD-affected cases and 358 controls from the Neurology Clinic of the University Hospital of Larissa, University of Thessaly, Faculty of Medicine, in Greece. The diagnosis of PD was made by a specialist neurologist according to the UK Parkinson's Disease Society Brain Bank's clinical criteria. All the participants were genotyped for the MOBP rs616147. Furthermore, in order to validate our results, we genotyped 327 patients with Alzheimer's disease (AD) for MOBP rs616147 and compared them with the control group.

RESULTS

According to the univariate analysis, there was a significant association between rs616147 and PD in the dominant (OR [95% C.I.] = 0.70 [0.52-0.94], p = .018), the overdominant (OR [95% C.I.] = 0.68 [0.50-0.92], p = .011), and in the codominant (G/A VS G/G; OR [95% C.I.] = 0.66 [0.48-0.91], p = .035) modes of inheritance. In contrast, there was no association between the MOBP rs616147 polymorphism and AD.

CONCLUSIONS

We provide preliminary results associating MOBP rs616147 genetic variant with PD.

Erythropoietin levels in children with obstructive sleep apnea

OBJECTIVE

High serum erythropoietin (EPO) levels have been reported in adult patients with obstructive sleep apnea (OSA), however there is a lack of related literature in children with OSA. The main objective of this study was to explore the potential use of EPO as a pediatric OSA biomarker by exploring the relationship between serum EPO levels and the presence of pediatric OSA.

METHODS AND MATERIALS

A prospective study was conducted on children (4-12 years old) referred for overnight PSG. Thirty (30) consecutive children with mild. 30 consecutives with moderate, and 30 consecutives with severe OSA (OSA group), as well as 30 consecutive children with AHI≤1 (non-OSA group) were recruited. Morning blood specimens after PSG studies were obtained in order to compare EPO levels.

RESULTS

Finally, 115 children included for analysis. Non-OSA group consisted of 29 children (mean age: 6.93 ± 2.10) and OSA-group of 86 children (mean age: 6.78 ± 2.53). Mean EPO values for the non-OSA and OSA groups were 5.46 ± 2.29 mIU/ml and 8.33 ± 4.10 mIU/ml respectively. OSA-group had significant higher EPO levels than non-OSA (P: 0.01) while EPO levels were significantly correlated with AHI (p < 0.001).

CONCLUSION

Our study showed that serum EPO levels of children with OSA are significantly higher than those without OSA and correlate significantly with AHI. These results suggest that EPO may be considered as a biomarker candidate for pediatric OSA. Since this may be the first study on the topic further research is needed.

Novel HIF-2α interaction with Reptin52 impairs HIF-2 transcriptional activity and EPO secretion

Hypoxia-inducible factor 2 (HIF-2), is essential for cellular response to hypoxia and holds an important role in erythropoiesis, angiogenesis, tissue invasion and metastasis, thus, constituting an important therapeutic target. Maximal HIF-2 transcriptional activation requires HIF-2α phosphorylation by ERK1/2 that impairs its CRM1-mediated nuclear export. Herein, we reveal a novel interaction of HIF-2α with Reptin52, a multifunctional protein involved in cellular functions orchestrated both in the nucleus and the cytoplasm. HIF-2α and Reptin52 interact both in nuclear and cytoplasmic fractions, however, ERK1/2 pathway inactivation seems to favour their association in the cytoplasm. Notably, we demonstrate that Reptin52 reduces HIF-2 transcriptional activity, which results in decreased EPO secretion under hypoxia, by impairing HIF-2α stability via a non-canonical PHD-VHL-proteasome independent mechanism. This interaction represents a novel HIF-2 fine tuning mechanism that allows for distinct HIF1/2 isoforms regulation.

Calcitriol Suppresses HIF-1 and HIF-2 Transcriptional Activity by Reducing HIF-1/2α Protein Levels via a VDR-Independent Mechanism

Hypoxia-inducible transcription factors 1 and 2 (HIFs) are major mediators of cancer development and progression and validated targets for cancer therapy. Although calcitriol, the biologically active metabolite of vitamin D, was attributed with anticancer properties, there is little information on the effect of calcitriol on HIFs and the mechanism underling this activity. Here, we demonstrate the negative effect of calcitriol on HIF-1/2α protein levels and HIF-1/2 transcriptional activity and elucidate the molecular mechanism of calcitriol action. We also reveal that the suppression of vitamin D receptor (VDR) expression by siRNA does not abrogate the negative regulation of HIF-1α and HIF-2α protein levels and HIF-1/2 transcriptional activity by calcitriol, thus testifying that the mechanism of these actions is VDR independent. At the same time, calcitriol significantly reduces the phosphorylation of Akt protein kinase and its downstream targets and suppresses HIF-1/2α protein synthesis by inhibiting HIF1A and EPAS1 (Endothelial PAS domain-containing protein 1) mRNA translation, without affecting their mRNA levels. On the basis of the acquired data, it can be proposed that calcitriol reduces HIF-1α and HIF-2α protein levels and inhibits HIF-1 and HIF-2 transcriptional activity by a VDR-independent, nongenomic mechanism that involves inhibition of PI3K/Akt signaling pathway and suppression of HIF1A and EPAS1 mRNA translation.

FGF-2 and HGF reverse abiraterone's effect οn intracellular levels of DHT in androgen-dependent and androgen independent prostate cancer cell lines

PURPOSE

Growth factors such as fibroblast growth factor 2 (FGF-2) and hepatocyte growth factor (HGF) appear at high levels in prostate cancer (PC). Abiraterone is an androgen biosynthesis inhibitor which is currently in use as a standard treatment in clinics to impair tumor growth. Development of resistance to anticancer therapies is unfortunately a very common feature of cancer cells that threatens the patient lives. This study aimed to investigate whether FGF-2 and HGF act as a possible resistant mechanism to the abiraterone activity on the androgen synthesis pathway in PC.

METHODS

The intracellular levels of 17-OH progesterone and dihydrotestosterone (DHT) were determined by enzyme immunoassays in cell lysates of LNCaP and PC3 PC cells upon co-treatment of cells with abiraterone and FGF-2 or HGF.

RESULTS

Abiraterone treatment resulted in significant reduction in the intracellular levels of 17-OH progesterone and DHT in both LnCap and PC3 cells. FGF-2 and HGF were found to decrease the intracellular levels of 17-OH progesterone in both cell lines, whereas HGF alone was found to increase the intracellular levels of DHT only in PC3 cells. However, the simultaneous exposure of cells to abiraterone and FGF-2 or HGF was found to result in an increase in the intracellular levels of DHT, while it did not result in changes in the intracellular levels of 17-OH progesterone.

CONCLUSION

These findings suggest that FGF-2 and HGF may act as an escape mechanism, aiding the development of resistance to abiraterone by restoring intra-tumoral androgen synthesis that may contribute to disease progression.

High-Tidal-Volume Mechanical Ventilation and Lung Inflammation in Intensive Care Patients With Normal Lungs

BACKGROUND

This study was conducted to investigate whether high-tidal-volume mechanical ventilation is associated with increased lung inflammation compared with low-tidal-volume mechanical ventilation in critically ill patients with no evidence of lung injury.

METHODS

In this prospective, single-blind, randomized (1:1), parallel-group study, 18 critically ill patients with normal lungs were randomly assigned to receive mechanical ventilation with a tidal volume of either 6 mL/kg (low tidal volume) or 12 mL/kg (high tidal volume) during the first 4 days in the intensive care unit.

RESULTS

At baseline and at 24, 48, and 96 hours, exhaled breath condensate was collected to measure interleukin 1β, interleukin 10, tumor necrosis factor α, and total nitric oxide metabolites. Interleukin 1β levels in exhaled breath condensate were significantly increased at 24 hours compared with baseline in the high-tidal-volume group but not in the low-tidal-volume group. The interleukin 1β increase in the high-tidal-volume group was transient. Exhaled breath condensate levels of interleukin 1β, interleukin 10, tumor necrosis factor α, and total nitric oxide metabolites did not differ significantly between the high-tidal-volume and low-tidal-volume groups at any time point.

CONCLUSION

Short-term mechanical ventilation with a tidal volume of 12 mL/kg may trigger inflammatory responses in the lungs of intensive care unit patients without preexisting lung injury.

17-β estradiol attenuates the pro-oxidant activity of corticotropin-releasing hormone in macroendothelial cells

Corticotropin-releasing hormone, which is the predominant regulator of neuroendocrine responses to stress, attenuates inflammation through stimulation of glucocorticoid release. Enhanced corticotropin-releasing hormone expression has been detected in inflammatory cells of the vascular endothelium, where it acts as a local regulator of endothelial redox homeostasis. Estrogens have beneficial effects on endothelial integrity and function, though the mechanism underlying their antioxidative effect remains as yet largely unknown. We therefore investigated the effect of 17β-estradiol on pro-oxidant action of corticotropin-releasing hormone in vitro in macroendothelial cells, and, more specifically, the role of 17β-estradiol on corticotropin-releasing hormone-induced activities/release of the antioxidant enzymes namely, endothelial nitric oxide synthase, superoxide dismutase, catalase, and glutathione. We observed that 17β-estradiol abolished the stimulatory effect of corticotropin-releasing hormone on intracellular reactive oxygen species levels and counteracted its inhibitory effect on endothelial nitric oxide synthase activity and nitric oxide release. In addition, 17β-estradiol significantly induced superoxide dismutase and catalase activity, an effect that was not significantly influenced by corticotropin-releasing hormone. Finally, 17β-estradiol significantly increased glutathione levels and the glutathione/glutathione + glutathione disulfide ratio, an action that was partially blocked by corticotropin-releasing hormone. Our results reveal that 17β-estradiol counterbalances corticotropin-releasing hormone-mediated pro-inflammatory action and thereby maintains the physiological threshold of the endothelial cell redox environment. These observations may be of importance, considering the protective role of estrogen in the development of atherosclerosis.

ERK1/2 phosphorylates HIF-2α and regulates its activity by controlling its CRM1-dependent nuclear shuttling

Hypoxia-inducible factor 2 (HIF-2) is a principal component of the cellular response to oxygen deprivation (hypoxia). Its inducible subunit, HIF-2α (also known as EPAS1), is controlled by oxygen-dependent as well as oxygen-independent mechanisms, such as phosphorylation. We show here that HIF-2α is phosphorylated under hypoxia (1% O2) by extracellular signal-regulated protein kinases 1 and 2 (ERK1/2; also known as MAPK3 and MAPK1, respectively) at serine residue 672, as identified by in vitro phosphorylation assays. Mutation of this site to an alanine residue or inhibition of the ERK1/2 pathway decreases HIF-2 transcriptional activity and causes HIF-2α to mislocalize to the cytoplasm without changing its protein expression levels. Localization, reporter gene and immunoprecipitation experiments further show that HIF-2α associates with the exportin chromosomal maintenance 1 (CRM1, also known as XPO1) in a phosphorylation-sensitive manner and identify two critical leucine residues as part of an atypical CRM1-dependent nuclear export signal (NES) neighboring serine 672. Inhibition of CRM1 or mutation of these residues restores nuclear accumulation and activity of HIF-2α lacking the ERK1/2-mediated modification. In summary, we reveal a novel regulatory mechanism of HIF-2, involving ERK1/2-dependent phosphorylation of HIF-2α, which controls its nucleocytoplasmic shuttling and the HIF-2 transcriptional activity.This article has an associated First Person interview with the first author of the paper.

Clinical value of significance of Hypoxia Inducible Factor-1α, Glucose Transporter-1 and Carbonic Anhydrase IX in rectal cancer after preoperative chemoradiotherapy

PURPOSE

The standard treatment of rectal cancer is surgery along with preoperative radiotherapy, administered alone or in combination with chemotherapy. Preoperative chemoradiotherapy (preCRT) is widely used as it allows better local control and the use of sphincter-saving surgery. Pathological response after preCRT has been shown to be a significant prognostic factor of rectal cancer recurrence and survival. In this review we will assess the value of Hypoxia Induced Factor 1α (HIF-1α), Carbonic Anhydrase IX (CA-9) and Glucose Transporter 1 (GLUT-1) genes as predictive markers of the course of local advanced rectal cancer in patients who underwent pre-CRT.

METHODS

We searched studies, from Pubmed and in English language, obtained the information by using "HIF-1 alpha", "Carbonic Anhydrase IX (CA-9)", "Glucose Transporter 1 (GLUT-1)" and "rectal cancer" as key words.

RESULTS

27 relevant articles were retrieved in initial stage. After full-text review, 13 articles were selected for the final analysis.

CONCLUSIONS

HIF-1α, GLUT-1 and CA-IX may be connected with tumor response to preCRT, however, there is still skepticism towards their clinical use as predictors of outcome. Therefore, there is a need to conduct larger and more extensive cohort studies in order to find whether these predictors can be used in practice.

The Role of Tissue Oxygen Tension in Dengue Virus Replication

Low oxygen tension exerts a profound effect on the replication of several DNA and RNA viruses. In vitro propagation of Dengue virus (DENV) has been conventionally studied under atmospheric oxygen levels despite that in vivo, the tissue microenvironment is hypoxic. Here, we compared the efficiency of DENV replication in liver cells, monocytes, and epithelial cells under hypoxic and normoxic conditions, investigated the ability of DENV to induce a hypoxia response and metabolic reprogramming and determined the underlying molecular mechanism. In DENV-infected cells, hypoxia had no effect on virus entry and RNA translation, but enhanced RNA replication. Overexpression and silencing approaches as well as chemical inhibition and energy substrate exchanging experiments showed that hypoxia-mediated enhancement of DENV replication depends on the activation of the key metabolic regulators hypoxia-inducible factors 1α/2α (HIF-1α/2α) and the serine/threonine kinase AKT. Enhanced RNA replication correlates directly with an increase in anaerobic glycolysis producing elevated ATP levels. Additionally, DENV activates HIF and anaerobic glycolysis markers. Finally, reactive oxygen species were shown to contribute, at least in part through HIF, both to the hypoxia-mediated increase of DENV replication and to virus-induced hypoxic reprogramming. These suggest that DENV manipulates hypoxia response and oxygen-dependent metabolic reprogramming for efficient viral replication.

Adhesion Prevention to Polypropylene Meshes Using Combined Icodextrin Four Percent and Dimetindene Maleate

BACKGROUND

The use of surgical meshes in ventral hernia repair has significantly reduced hernia recurrence rates. However, when placed intraperitoneally prosthetic materials can trigger the development of peritoneal adhesions. The present experimental study evaluated the combined icodextrin 4% and dimetindene maleate treatment in preventing peritoneal adhesion formation to polypropylene and titanium-coated polypropylene meshes.

MATERIALS AND METHODS

Sixty female white rabbits were divided into four groups. A 2 × 2 cm piece of mesh was fixed to intact peritoneum in all animals through a midline laparotomy. A lightweight polypropylene mesh was implanted in groups 1 and 2 and a titanium-coated polypropylene mesh in groups 3 and 4. Groups 2 and 4 were treated, intraoperatively, with intravenous dimetindene maleate (0.1 mg/kg) and intraperitoneal solution of icodextrin 4% (20 mL/kg) and for the next 6 d with dimetindene maleate intramuscularly. The observation period lasted 15 d. Adhesion scores, percentage of mesh affected surface, tissue hydroxyproline levels, and tissue histopathology were examined.

RESULTS

All animals in group 1 and 57% of animals in group 3 presented postoperative adhesions. The combination of antiadhesives significantly reduced the extent and severity of adhesions as well as the hydroxyproline levels in groups 2 and 4 compared with groups 1 and 3. On microscopic evaluation, animals in group 1 exhibited higher inflammation scores compared with group 2, whereas animals in groups 2 and 4 had better mesotheliazation compared with groups 1 and 3.

CONCLUSIONS

The combined administration of icodextrin 4% and dimetindene maleate reduces the extent and severity of adhesions and may be successfully used to prevent adhesion formation after mesh intraperitoneal placement.

Hypoxia upregulates integrin gene expression in microvascular endothelial cells and promotes their migration and capillary-like tube formation

Tissue hypoxia affects gene expression through the hypoxia-inducible transcription factors, HIF-1 and HIF-2, in both physiological and pathological angiogenesis. Angiogenesis is a complex response of endothelial cells integrating cell proliferation, migration, tube formation, and their interaction with the extracellular matrix through integrin receptors. In this report, we studied the effect of hypoxia on the angiogenic functions of human microvascular endothelial cells (HMEC-1) as well as on expression of the angiogenic integrins α_ν β₃ , α_ν β₅ , and α₅ β₁ . Exposure of HMEC-1 to hypoxia (1% O₂ ) or to DMOG, a prolyl-4-hydroxylase inhibitor, caused significant reduction to their proliferation rate, whereas their migration ability toward laminin-1 or collagen IV and capillary-like tube formation were significantly enhanced. In addition, α_v , β₁ , β₃ , and β₅ integrins expression was increased under hypoxia in HMEC-1, while α₅ integrin was not affected. Both HIF-1 and HIF-2 protein expression and transcriptional activity were induced under hypoxia in HMEC-1. The knockdown of either HIF-1α or HIF-2α inhibited integrin β₃ hypoxic stimulation, suggesting a HIF-dependent induction of β₃ integrin in HMEC-1. Taken together, our results indicate that hypoxia transcriptionally up-regulates angiogenic integrins in microvascular endothelial cells along with promoting migration and tube formation of HMEC-1.

HIF-2α phosphorylation by CK1δ promotes erythropoietin secretion in liver cancer cells under hypoxia

Hypoxia inducible factor 2 (HIF-2) is a transcriptional activator implicated in the cellular response to hypoxia. Regulation of its inducible subunit, HIF-2α (also known as EPAS1), involves post-translational modifications. Here, we demonstrate that casein kinase 1δ (CK1δ; also known as CSNK1D) phosphorylates HIF-2α at Ser383 and Thr528 in vitro We found that disruption of these phosphorylation sites, and silencing or chemical inhibition of CK1δ, reduced the expression of HIF-2 target genes and the secretion of erythropoietin (EPO) in two hepatic cancer cell lines, Huh7 and HepG2, without affecting the levels of HIF-2α protein expression. Furthermore, when CK1δ-dependent phosphorylation of HIF-2α was inhibited, we observed substantial cytoplasmic mislocalization of HIF-2α, which was reversed upon the addition of the nuclear protein export inhibitor leptomycin B. Taken together, these data suggest that CK1δ enhances EPO secretion from liver cancer cells under hypoxia by modifying HIF-2α and promoting its nuclear accumulation. This modification represents a new mechanism of HIF-2 regulation that might allow HIF isoforms to undertake differing functions.

A Distributed Infrastructure for Earth-Science Big Data Retrieval

Earth-Science data are composite, multi-dimensional and of significant size, and as such, continue to pose a number of ongoing problems regarding their management. With new and diverse information sources emerging as well as rates of generated data continuously increasing, a persistent challenge becomes more pressing: To make the information existing in multiple heterogeneous resources readily available. The widespread use of the XML data-exchange format has enabled the rapid accumulation of semi-structured metadata for Earth-Science data. In this paper, we exploit this popular use of XML and present the means for querying metadata emanating from multiple sources in a succinct and effective way. Thereby, we release the user from the very tedious and time consuming task of examining individual XML descriptions one by one. Our approach, termed Meta-Array Data Search (MAD Search), brings together diverse data sources while enhancing the user-friendliness of the underlying information sources. We gather metadata using different standards and construct an amalgamated service with the help of tools that discover and harvest such metadata; this service facilitates the end-user by offering easy and timely access to all metadata. The main contribution of our work is a novel query language termed xWCPS, that builds on top of two widely-adopted standards: XQuery and the Web Coverage Processing Service (WCPS). xWCPS furnishes a rich set of features regarding the way scientific data can be queried with. Our proposed unified language allows for requesting metadata while also giving processing directives. Consequently, the xWCPS-enabled MAD Search helps in both retrieval and processing of large data sets hosted in an heterogeneous infrastructure. We demonstrate the effectiveness of our approach through diverse use-cases that provide insights into the syntactic power and overall expressiveness of xWCPS. We evaluate MAD Search in a distributed environment that comprises five high-volume array-databases whose sizes range between 20 and 100 GB and so, we ascertain the applicability and potential of our proposal.

Cobalt stimulates HIF-1-dependent but inhibits HIF-2-dependent gene expression in liver cancer cells

Hypoxia-inducible factors (HIFs) are transcriptional regulators that mediate the cellular response to low oxygen. Although HIF-1 is usually considered as the principal mediator of hypoxic adaptation, several tissues and different cell types express both HIF-1 and HIF-2 isoforms under hypoxia or when treated with hypoxia mimetic chemicals such as cobalt. However, the similarities or differences between HIF-1 and HIF-2, in terms of their tissue- and inducer-specific activation and function, are not adequately characterized. To address this issue, we investigated the effects of true hypoxia and hypoxia mimetics on HIF-1 and HIF-2 induction and specific gene transcriptional activity in two hepatic cancer cell lines, Huh7 and HepG2. Both hypoxia and cobalt caused rapid induction of both HIF-1α and HIF-2α proteins. Hypoxia induced erythropoietin (EPO) expression and secretion in a HIF-2-dependent way. Surprisingly, however, EPO expression was not induced when cells were treated with cobalt. In agreement, both HIF-1- and HIF-2-dependent promoters (of PGK and SOD2 genes, respectively) were activated by hypoxia while cobalt only activated the HIF-1-dependent PGK promoter. Unlike cobalt, other hypoxia mimetics such as DFO and DMOG activated both types of promoters. Furthermore, cobalt impaired the hypoxic stimulation of HIF-2, but not HIF-1, activity and cobalt-induced HIF-2α interacted poorly with USF-2, a HIF-2-specific co-activator. These data show that, despite similar induction of HIF-1α and HIF-2α protein expression, HIF-1 and HIF-2 specific gene activating functions respond differently to different stimuli and suggest the operation of oxygen-independent and gene- or tissue-specific regulatory mechanisms involving additional transcription factors or co-activators.

Effect of ET-1, FGF-2, and HGF on intracellular steroidogenesis in prostate cancer cells

e16083

Background: In the prostatic epithelium endothelin-1 (ET-1), fibroblast growth factor-2 (FGF2) and hepatocyte growth factor (HGF) are involved in cell proliferation and inhibition of apoptosis. The aim of this study is to investigate whether neuropeptides such as ET-1 and growth factors such as FGF and HGF may constitute an alternate pathway to intracellular steroidogenesis. Methods: PC3 cells, an androgen independent prostate cancer cell line were cultured in RPMI 1640, fully supplemented with FBS 10% and in serum free conditions. The cells were incubated with ET-1(10nM, 3 hrs incubation), FGF-2 (10 ng/ml, 3 hrs incubation) and HGF(33 ng/ml, 3 hrs incubation), and then progesterone, 17-OH progesterone and aldosterone were measured in cell lysates by LC-MS using LTQ Orbitrap XL MS 2.5.5 SP1 (Thermo-Fisher) equipped with Accela AS 2.2.1, Accela pump. The data were analysed by Xcalibur 2.1.0 Software. Results: In baseline conditions PC3 cells produce no progesterone but high amounts of 17-OH progesterone and small amounts of aldosterone. Upon stimulation with endothelin there was a significant increase in progesterone, significant decrease in 17-OH progesterone and a very significant increase in aldosterone. Similarly stimulation with both HGF and FGF resulted in significant decreases in 17-OH progesterone and increases in aldosterone. Conclusions: Our results imply that in androgen deprivation conditions intracellular steroidogenesis can still take place by stimulation via seven membrane and tyrosine kinase receptors, contributing in part to a steroid dependent phenotype in addition to a steroid independent one, thus implying the potential for new therapeutic interventions.

MgcRacGAP, a cytoskeleton regulator, inhibits HIF-1 transcriptional activity by blocking its dimerization

Hypoxia inducible factor-1 (HIF-1), a dimeric transcription factor of the bHLH-PAS family, is comprised of HIF-1α, which is inducible by hypoxia and ARNT or HIF-1β, which is constitutively expressed. HIF-1 is involved in cellular homeostasis under hypoxia, in development and in several diseases affected by oxygen availability, particularly cancer. Since its expression is positively correlated with poor outcome prognosis for cancer patients, HIF-1 is a target for pharmaceutical therapy. We have previously shown that male germ cell Rac GTPase activating protein (MgcRacGAP), a regulator of Rho proteins which are principally involved in cytoskeletal organization, binds to HIF-1α and inhibits its transcriptional activity. In this work, we have explored the mechanism of the MgcRacGAP-mediated HIF-1 inactivation. We show that the Myo domain of MgcRacGAP, which is both necessary and sufficient for HIF-1 repression, binds to the PAS-B domain of HIF-1α. Furthermore MgcRacGAP competes with ARNT for binding to the HIF-1α PAS-B domain, as shown by in vitro binding pull down assays. In mammalian cells, ARNT overexpression can overcome the MgcRacGAP-mediated inhibition and MgcRacGAP binding to HIF-1α in vivo inhibits its dimerization with ARNT. We additionally present results indicating that MgcRacGAP binding to HIF-1α is specific, since it does not affect the transcriptional activity of HIF-2, a close evolutionary relative of HIF-1 also involved in hypoxia regulation and cancer. Our results reveal a new mechanism for HIF-1 transcriptional activity regulation, suggest a novel hypoxia-cytoskeleton link and provide new tools for selective HIF-1 inhibition.

Secondhand smoke exposure induces acutely airway acidification and oxidative stress

Previous studies have shown that secondhand smoke induces lung function impairment and increases proinflammatory cytokines. The aim of the present study was to evaluate the acute effects of secondhand smoke on airway acidification and airway oxidative stress in never-smokers. In a randomized controlled cross-over trial, 18 young healthy never-smokers were assessed at baseline and 0, 30, 60, 120, 180 and 240 min after one-hour secondhand smoke exposure at bar/restaurant levels. Exhaled NO and CO measurements, exhaled breath condensate collection (for pH, H(2)O(2) and NO(2)(-)/NO(3)(-) measurements) and spirometry were performed at all time-points. Secondhand smoke exposure induced increases in serum cotinine and exhaled CO that persisted until 240 min. Exhaled breath condensate pH decreased immediately after exposure (p < 0.001) and returned to baseline by 180 min, whereas H(2)O(2) increased at 120 min and remained increased at 240 min (p = 0.001). No changes in exhaled NO and NO(2)/NO(3) were observed, while decreases in FEV(1) (p < 0.001) and FEV(1)/FVC (p < 0.001) were observed after exposure and returned to baseline by 180 min. A 1-h exposure to secondhand smoke induced airway acidification and increased airway oxidative stress, accompanied by significant impairment of lung function. Despite the reversal in EBC pH and lung function, airway oxidative stress remained increased 4 h after the exposure. Clinical trial registration number (EudraCT): 2009-013545-28.

Hypoxia causes triglyceride accumulation by HIF-1-mediated stimulation of lipin 1 expression

Adaptation to hypoxia involves hypoxia-inducible transcription factors (HIFs) and requires reprogramming of cellular metabolism that is essential during both physiological and pathological processes. In contrast to the established role of HIF-1 in glucose metabolism, the involvement of HIFs and the molecular mechanisms concerning the effects of hypoxia on lipid metabolism are poorly characterized. Here, we report that exposure of human cells to hypoxia causes accumulation of triglycerides and lipid droplets. This is accompanied by induction of lipin 1, a phosphatidate phosphatase isoform that catalyzes the penultimate step in triglyceride biosynthesis, whereas lipin 2 remains unaffected. Hypoxic upregulation of lipin 1 expression involves predominantly HIF-1, which binds to a single distal hypoxia-responsive element in the lipin 1 gene promoter and causes its activation under low oxygen conditions. Accumulation of hypoxic triglycerides or lipid droplets can be blocked by siRNA-mediated silencing of lipin 1 expression or kaempferol-mediated inhibition of HIF-1. We conclude that direct control of lipin 1 transcription by HIF-1 is an important regulatory feature of lipid metabolism and its adaptation to hypoxia.

Bortezomib reverses the proliferative and antiapoptotic effect of neuropeptides on prostate cancer cells

OBJECTIVES

Neuropeptides are important signal initiators in advanced prostate cancer, partially acting through activation of nuclear factor kappa B. Central to nuclear factor kappa B regulation is the ubiquitin-proteasome system, pharmacological inhibition of which has been proposed as an anticancer strategy. We investigated the putative role of the proteasome inhibitor bortezomib in neuropeptides signaling effects on prostate cancer cells.

METHODS

Human prostate cancer cell lines, LNCaP and PC-3, were used to examine cell proliferation, levels of proapoptotic (caspase-3, Bad) and cell cycle regulatory proteins (p53, p27, p21), as well as total and phosphorylated Akt and p44/42 mitogen-activated protein kinase proteins. Furthermore, 20S proteasome activity, subcellular localization of nuclear factor kappa B and transcription of nuclear factor kappa B target genes, interleukin-8 and vascular endothelial growth factor, were assessed.

RESULTS

Neuropeptides (endothelin-1, bombesin) increased cell proliferation, whereas bortezomib decreased proliferation and induced apoptosis, an effect maintained after cotreatment with neuropeptides. Bad, p53, p21 and p27 were downregulated by neuropeptides in PC-3, and these effects were reversed with the addition of bortezomib. Neuropeptides increased proteasomal activity and nuclear factor kappa B levels in PC-3, and these effects were prevented by bortezomib. Interleukin-8 and vascular endothelial growth factor transcripts were induced after neuropeptides treatment, but downregulated by bortezomib. These results coincided with the ability of bortezomib to reduce mitogen-activated protein kinase signaling in both cell lines.

CONCLUSIONS

These findings are consistent with bortezomib-mediated abrogation of neuropeptides-induced proliferative and antiapoptotic signaling. Thus, the effect of the drug on the neuropeptides axis needs to be further investigated, as neuropeptide action in prostate cancer might entail involvement of the proteasome.

Bortezomib represses HIF-1α protein expression and nuclear accumulation by inhibiting both PI3K/Akt/TOR and MAPK pathways in prostate cancer cells

Bortezomib represents the first proteasome inhibitor (PI) with demonstrated antitumor activity in the clinical setting, particularly for treatment of hematological malignancies. At the preclinical level, its action is shown to be mediated by induction of growth arrest and apoptosis in many tumor types, including androgen-dependent (AD) and androgen-independent (AI) prostate cancer (PCa) cells. Hypoxia-inducible factor-1α (HIF-1α), which is directly involved in tumor growth, is one of the most studied and promising molecular targets for anti-cancer therapy and is often overexpressed in PCa. Bortezomib has been reported to impair tumor growth by also inhibiting HIF-1α. In this study, we investigated the effect of bortezomib on the expression, activity and localization of HIF-1α in LNCaP (AD) and PC3 (AI) PCa cells. First, we show that hypoxic upregulation of HIF-1α protein levels and activity involves both the PI3K/Akt/mTOR and p44/42 MAPK pathways. Second, bortezomib inhibits expression of HIF-1α protein under both normoxic and hypoxic conditions, represses HIF-1 transcriptional activity and attenuates the release of vascular endothelial growth factor. These effects correlate with the ability of bortezomib to cause dephosphorylation of phospho-Akt, phospho-p70S6K, and phospho-S6RP, thus inactivating a pathway known to be required for HIF-1α protein expression at the translational level. Furthermore, bortezomib also abrogates p44/42 MAPK phosphorylation, which results to reduced nuclear translocation of HIF-1α. Taken together, these results suggest that bortezomib inhibits HIF-1α protein synthesis and its nuclear targeting through suppression of PI3K/Akt/mTOR and MAPK pathways, respectively, in both AD and AI PCa cells.

Exposure of differentiated airway smooth muscle cells to serum stimulates both induction of hypoxia-inducible factor-1α and airway responsiveness to ACh

Airway smooth muscle (ASM) cells are characterized by phenotypic plasticity and can switch between differentiated and proliferative phenotypes. In rabbit tracheal ASM cells that had been differentiated in vitro by serum starvation, readdition of FBS caused initiation of proliferation and induction of nuclear and transcriptionally active hypoxia-inducible factor (HIF)-1α. In addition, FBS stimulated the induction of HIF-1α by the hypoxia mimetic cobalt. Treatment with actinomycin D, cycloheximide, the phosphatidylinositol 3-kinase inhibitors LY-294002 and wortmannin or the reactive oxygen species scavenger diphenyleneiodonium inhibited the FBS-dependent induction of HIF-1α. These data indicate that, in differentiated ASM cells, FBS upregulates HIF-1α by a transcription-, translation-, phosphatidylinositol 3-kinase-, and reactive oxygen species-dependent mechanism. Interestingly, addition of FBS and cobalt also induced HIF-1α in organ cultures of rabbit trachea strips and synergistically increased their contractile response to ACh, suggesting that HIF-1α might be implicated in airway hypercontractility.

The flavonoid quercetin induces hypoxia-inducible factor-1alpha (HIF-1alpha) and inhibits cell proliferation by depleting intracellular iron

Quercetin, a flavonoid with anti-oxidant, metal chelating, kinase modulating and anti-proliferative properties, can induce hypoxia-inducible factor-1alpha (HIF-1alpha) in normoxia, but its mechanism of action has not been determined. In this study we characterized the induction of HIF-1alpha and the inhibition of cell proliferation caused by quercetin in HeLa and ASM (airway smooth muscle) cells and examined the effect of iron on these processes. Furthermore, we investigated the relevance of the intracellular levels of quercetin to HIF-1alpha expression and cell proliferation. Our data demonstrate that quercetin depletes intracellular calcein-chelatable iron and that supplying additional iron from extracellular or intracellular pools abrogates the induction of HIF-1alpha by quercetin. Moreover, addition of iron reverses the quercetin-induced inhibition of DNA synthesis, cell proliferation and cycle progression, but to different extents, depending on cell type. We propose that quercetin stabilises HIF-1alpha and inhibits cell proliferation predominantly by decreasing the concentration of intracellular iron through chelation.

Lower prevalence of epsilon 4 allele of apolipoprotein E gene in healthy, longer-lived individuals of Hellenic origin

Apolipoprotein E (ApoE), and especially its epsilon4 isoform, is considered a risk factor predisposing to coronary heart disease. We hypothesized that the absence of epsilon4 allele offers a better chance for longer life. So we compared the prevalence of ApoE genotypes in 80 healthy aged individuals (HAI) (>80 years) and 391 Greek adults (median age 43 years) with ApoE genotype distribution consistent with the Hardy-Weinberg equilibrium (chi(2) = 5.93, p >.05). ApoE genotypes were comparable in both groups with the exception of E3/3 and E3/4, which were significantly higher (87.50% vs 75.99%, p =.025) and lower (5.00% vs 13.19%, p =.036), respectively, in HAI. The epsilon2 and epsilon3 allele frequencies were not different between the groups. The epsilon4 allele was significantly less frequent in HAI compared to controls (3.1% vs 8.58%, p =.020). Our results indicate an unfavorable effect of epsilon4 allele on longevity that may be attenuated by environmental and/or other genetic factors.

Inhibition of the Na+-H+ exchanger isoform-1 and the extracellular signal-regulated kinase induces apoptosis: a time course of events

AIMS

The present study attempts to shed light on the role and the relative position of the Na(+)/H(+) exchanger isoform 1 (NHE1) and the extracellular signal-regulated kinase (ERK) in HEp-2 cell signaling pathways concerning a diverse range of cellular functions such as regulation of intracellular pH (pHi), DNA synthesis, production of reactive oxygen species (ROS) and apoptosis.

METHODS

Pharmacological inhibition with cariporide (highly specific inhibitor of NHE1) and PD98059 (specific inhibitor of the upstream activator of ERK) was implemented. Fluorescence spectrometry, atomic absorption spectrometry and ELISA methods were used in order to obtain the results.

RESULTS

NHE1 and ERK take part in all of the aforementioned cellular functions, as their inhibition had an effect on all of them. Additionally, inhibition of NHE1 resulted in ERK inhibition as well. Moreover, continuous inhibition of NHE1 or ERK for up to 24h led HEp-2 cells to apoptosis, as assessed through caspase-3 activation, DNA fragmentation and annexin-V binding levels.

CONCLUSION

Our data shows a time course of events in relation to NHE1 and ERK and suggests the existence of a positive feedback loop between NHE1 and ERK which could pose a barrier against apoptosis.

Cobalt induces hypoxia-inducible factor-1alpha (HIF-1alpha) in HeLa cells by an iron-independent, but ROS-, PI-3K- and MAPK-dependent mechanism

The iron-chelator desferrioxamine (DFO) and the transition metal cobalt induce hypoxia-inducible factor-1alpha (HIF-1alpha) in normoxia. DFO stabilizes HIF-1alpha from proteolysis by inhibiting the activity of iron-dependent prolyl hydroxylases, but the mechanism of action of cobalt is not fully elucidated. The purpose of this study was to examine the regulation of HIF-1alpha induction and HeLa cell proliferation by cobalt and the role of iron in these processes. Our results show that, unlike DFO, induction of transcriptionally active HIF-1alpha by CoCl2 cannot be abrogated by the addition of excess Fe3+, but involves the production of reactive oxygen species (ROS) and the operation of the phosphatidylinositol-3 kinase (PI-3K) and MAPK pathways. CoCl2, as well as DFO, decreased HeLa cell proliferation, but these effects were reversed by the addition of Fe3+. We conclude that the effect of cobalt on cell proliferation is iron-dependent, while its effects on HIF-1alpha induction are ROS- and signaling pathways-dependent, but iron-independent.

Stimulation of Na+/H+ antiport and pyruvate kinase activities by high glucose concentration in human erythrocytes

This study aims to demonstrate the effect of high glucose concentrations on NHE-1 and PK activities and investigate the implicated signal transduction pathways. Erythrocytes drawn from healthy volunteers were incubated in the presence of 5 or 50 mM of glucose, fructose, galactose or mannitol. When appropriate, specific inhibitors of NHE-1, PKC or p42/44 MAPK were used. Erythrocyte NHE-1 activity has been estimated by fluorometrical determination of the intracellular pH and quantification of sodium uptake using 22Na. Pyruvate kinase activity was measured by a NADH-lactate dehydrogenase enzymatic assay. p42/44 MAPK activity was assessed with a specific enzyme linked immunosorbent assay (ELISA). Increased concentrations of glucose but not galactose, fructose or mannitol enhanced erythrocyte NHE-1, PK and p42/44 MAPK activity. Inhibition of PKC, counteracted these effects of glucose. Similarly, inhibition of NHE 1 abolished the effect of high glucose on PK and p42/44 MAPK as well. Finally, inhibition of p42/44 MAPK also hindered the effect of glucose on NHE-1 and PK activities. The data of the present study indicate an acute effect of glucose on signal transduction pathways in human erythrocytes. This pathway involves NHE-1, PKC, and p42/44 MAPK. A positive feedback between NHE 1 and p42/44 MAPK is suggested.

Transforming growth factor beta1 inhibits aldosterone and cortisol production in the human adrenocortical cell line NCI-H295R through inhibition of CYP11B1 and CYP11B2 expression

Transforming growth factor beta1 (TGFbeta1) has been shown to exert strong inhibitory effects on adrenocortical cell steroidogenesis. However, the molecular targets of TGFbeta1 in adrenocortical cells appear to differ between species. Here, we report the first characterization of the regulatory effects of TGFbeta1 on the steroidogenic functions of the human adrenocortical tumor cell line NCI-H295R. After treatment with 2 ng/ml TGFbeta1 for 24 h, basal production of corticosterone, cortisol and androstenedione was dramatically decreased. When TGFbeta1 was added simultaneously with forskolin, the production of cortisol and 11-hydroxyandrostenedione was decreased by 85% whereas that of deoxycortisol was increased. When TGFbeta1 was added simultaneously with angiotensin II, aldosterone production was reduced by 80%. We observed that TGFbeta1 strongly inhibits forskolin-induced steroid 11beta-hydroxylase activity and CYP11B1 mRNA levels, as well as angiotensin II-induced aldosterone synthase activity and CYP11B2 mRNA levels. CYP11B1 and CYP11B2 gene products thus appear as the major steroidogenic enzymes down-regulated by TGFbeta1 in the human adrenocortical tumor cell line NCI-H295R.

Evaluation of the efficacy of pelvic shielding in preadolescent girls

SUMMARY

A standing anteroposterior pelvic radiograph with gonadal shielding is used as a screening tool for all patients evaluated for intoeing at our institution. Sixty-two normal consecutive screening pelvic radiographs obtained in 61 female patients between the ages of 4 and 6 years were evaluated. Radiographs were evaluated for the adequacy to assess the hips as well as the protection afforded the ovaries from radiation exposure. Radiographs were judged to be inadequate because the shield covered essential landmarks in at least one hip in eight radiographs (13%). Five radiographs (8%) covered >50% of the area of both ovaries, and only one radiograph covered >75% of the area of both ovaries. Standard techniques of positioning gonadal shields in preadolescent girls are inadequate and provide minimal protection with a high rate of interference with vital landmarks. We no longer advocate using gonadal shields on initial screening radiographs of preadolescent girls.

ACTH-regulated expression of vascular endothelial growth factor in the adult bovine adrenal cortex: a possible role in the maintenance of the microvasculature

Endothelial cells lining vessels of endocrine tissues are fenestrated. Interactions with the local environment via either soluble factors or cell-cell interactions appear to govern this terminal endothelial differentiation. Adrenocorticotropin (ACTH) has previously been reported to modulate endothelial fenestration in the rat adrenal cortex. Since vascular endothelial growth factor (VEGF) has been characterized as a potent inducer of endothelial fenestration, we aimed to characterize the status of VEGF expression in the bovine adult adrenal cortex and asked whether ACTH may regulate VEGF expression. By immunohistochemical analysis, we observed VEGF expression in steroidogenic cells from both zona glomerulosa and zona fasciculata of the bovine adrenal cortex. Double-labeling experiments performed on isolated cells in primary culture revealed VEGF immunoreactivity, essentially colocalized with the Golgi apparatus. The expression of two predominant VEGF isoforms, VEGF(121) and VEGF(165), was observed by RT-PCR analysis. ACTH (10 nM) was found to rapidly (within 2-4 h) increase the abundance of these VEGF transcripts, as assessed by both RT-PCR and Northern blot analysis. In parallel, ACTH significantly induced VEGF secretion into the medium of fasciculata cells in primary culture. Thus, our data are consistent with the involvement of ACTH, through its regulation of VEGF expression, in the maintenance of the adult adrenal cortex endothelium.

Bilateral laparoscopic adrenalectomy for congenital adrenal hyperplasia with severe hypertension, resulting from two novel mutations in splice donor sites of CYP11B1

We present an in vivo and in vitro study of congenital adrenal hyperplasia in a patient with 11beta-hydroxylase deficiency. Sequencing of the CYP11B1 gene showed two new base substitutions, a conservative 954 G-->C transversion at the last base of exon 5 (T318T), and a IVS8 + 4A-->G transition in intron 8. In addition, two polymorphisms were found in exons 1 and 2. The genetically female patient was raised as a male because of severe pseudohermaphroditism. Glucocorticoid-suppressive treatment encountered difficulties in equilibration and compliance, resulting in uncontrolled hypertension with pronounced hypertrophic cardiomyopathy. At 42 yr of age the occurrence of central retinal vein occlusion with permanent loss of left eye vision led to the decision to perform bilateral laparoscopic adrenalectomy. Surgery was followed by normalization of blood pressure and good compliance with glucocorticoid and androgen substitutive therapies. In vitro, adrenal cells in culture and isolated mitochondria showed extremely low 11beta-hydroxylase activity. Analysis of adrenal CYP11B1 messenger ribonucleic acid (mRNA) by RT-PCR and sequencing showed the expression of a shorter mRNA that lacked exon 8 and did not contain either the exon 5 mutation or the exon 1 and 2 polymorphisms. This suggested that one CYP11B1 allele carried the intron 8 mutation, responsible for skipping exon 8. The other allele carried the exon 5 mutation, and its mRNA was not detectable. Western blot analysis showed weak expression of a shorter CYP11B immunoreactive band of 43 kDa, consistent with truncation of exon 8. Thus, bilateral adrenalectomy in this patient allowed effective treatment of severe hypertension and helped in understanding the mechanisms and physiopathological consequences of two novel mutations of CYP11B1.

Expression and regulation of melanocortin receptor-5 (MC5-R) in the bovine adrenal cortex

Among the five members of the melanocortin receptor (MC-R) family, MC2 and MC5 are expressed in peripheral tissues. The receptor MC2 (ACTH receptor) almost exclusively expressed in the adrenal cortex whereas MC5-R is expressed in several organs including the adrenal cortex. Both receptors bind ACTH and activate adenylate cyclase. The aim of this work was to study the spatial distribution of MC5-R among the different zones of the bovine adrenal cortex and to analyze the regulation of its expression by its own ligands, ACTH and alpha-MSH and by angiotensin II (AII). Using semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) analysis and RNase protection assay, MC5-R was detected only in the glomerulosa zone whereas MC2-R was present in both glomerulosa and fasciculata zones of adult adrenal cortex. Treatments by ACTH, alpha-MSH, or AII increased the MC5-R mRNA level in glomerulosa cells by factors 7, 5, and 4.5, respectively. However, although potentially regulated by hormones, MC5-R is expressed at a level at least 100 times less than MC2-R, suggesting that MC5-R expression might only be at trace levels in grown adults, but could be much higher during embryogenesis.

Cushing's syndrome due to a gastric inhibitory polypeptide-dependent adrenal adenoma: insights into hormonal control of adrenocortical tumorigenesis

We studied a patient with food-induced, ACTH-independent, Cushing's syndrome and a unilateral adrenocortical adenoma. In vivo cortisol secretion was stimulated by mixed, glucidic, lipidic, or proteic meals. Plasma ACTH levels were undetectable, but iv injection of ACTH stimulated cortisol secretion. Unilateral adrenalectomy was followed by hypocortisolism with loss of steroidogenic responses to both food and ACTH. In vitro, cortisol secretion by isolated tumor cells was stimulated by the gut hormone gastric inhibitory polypeptide (GIP) and ACTH, but not by another gut hormone, glucagon-like peptide-1 (GLP-1). Both peptides stimulated the production of cAMP but not of inositol 1,4,5-trisphosphate. In quiescent cells, GIP and ACTH stimulated [3H]thymidine incorporation and p42-p44 mitogen-activated protein kinase activity. GIP receptor messenger ribonucleic acid (RNA), assessed by RT-PCR, was highly expressed in the tumor, whereas it was undetectable in the adjacent hypotrophic adrenal tissue, in two adrenal tumors responsible for food-independent Cushing's syndrome, and in two hyperplastic adrenals associated with ACTH hypersecretion. In situ hybridization demonstrated that expression of GIP receptor RNA was confined to the adrenocortical tumor cells. Low levels of ACTH receptor messenger RNA were also detectable in the tumor. We conclude that abnormal expression of the GIP receptor allows adrenocortical cells to respond to food intake with an increase in cAMP that may participate in the stimulation of both cortisol secretion and proliferation of the tumor cells.

Expression of ACTH receptors (MC2-R and MC5-R) in the glomerulosa and the fasciculata-reticularis zones of bovine adrenal cortex

The recent cloning of a family of melanocortin receptors (MC-R) has identified five distinct G protein- and adenylate cyclase-coupled receptors. The MC2-receptor (MC2-R) preferentially binds ACTH. It is expressed in the adrenal cortex and is hence considered to be the ACTH receptor. The MC5-receptor (MC5-R) binds ACTH and alpha-MSH and is more widely expressed. The aim of this work was to study the sites of MC5-R expression in the bovine adrenal cortex and to compare the regulation of the expression of MC2-R and MC5-R in bovine adrenocortical cells in primary culture. Analysis of the expression of MC5-R was obtained by RT-PCR, using total RNA purified from glomerulosa and fasciculata zones of bovine adrenocortical tissue. MC5-R expression could be detected in RNA from the glomerulosa zone but was undetectable in the fasciculata zone. In bovine adrenocortical cells in culture, ACTH stimulates MC5-R expression in the glomerulosa and fasciculata cells. A DNA fragment, was obtained using primers based on the bovine ACTH receptor (MC2-R) sequence. This fragment was detected in RNA from the two zones. The probe was used to quantify MC2-R by Ribonuclease Protection assay and we observed that MC2-R mRNA is 3.6-fold more abundant in glomerulosa than in fasciculata-reticularis cells.

Gastric inhibitory polypeptide (GIP) stimulates cortisol secretion, cAMP production and DNA synthesis in an adrenal adenoma responsible for food-dependent Cushing's syndrome

We studied in vitro an adrenal tumor responsible for food-dependent, ACTH independent, Cushing's's syndrome. Cortisol secretion by isolated tumor cells was stimulated by GIP and ACTH, but not by the gut hormone glucagon-like peptide-1 (GLP-1). Both GIP and ACTH stimulated production of cAMP but not inositol 1,4,5-trisphosphate IP3). In quiescent tumor cells, GIP and ACTH stimulated [3H]-thymidine incorporation and p42-p44 MAP kinase activity. In normal human adrenocortical cells cortisol secretion and [3H]-thymidine incorporation were stimulated by ACTH but not by GIP. GIP receptor mRNA, assessed by RT-PCR, was highly expressed in the tumor, but undetectable in the adjacent hypotrophic adrenal tissue, in a normal adrenal, in two adrenal tumors responsible for food-independent Cushing's syndrome and in two hyperplastic adrenals associated with ACTH hypersecretion. Low levels of ACTH receptor mRNA were also detectable in the tumor. We conclude that abnormal expression of the GIP receptor allows adrenocortical cells to respond to food intake with an increase of cAMP that may participate in stimulation of both cortisol secretion and proliferation of the tumor cells.

ANG II AT1 and AT2 receptors both inhibit bFGF-induced proliferation of bovine adrenocortical cells

Angiotensin II (ANG II) has long been known for its pressor and growth-promoting effects, which are both mediated by the AT1 receptor. By contrast, the AT2 receptor has recently been reported to mediate inhibition of proliferation through as yet undefined mechanisms. We report here that in bovine adrenal fasciculata cells ANG II by itself does not affect growth but inhibits basic fibroblast growth factor (bFGF)-induced DNA synthesis and blocks the cells in G1 phase. Consistent with this, ANG II inhibits cyclin D1 expression and cyclin D1-associated kinase activity. The antimitogenic effect of ANG II is partly mimicked by the AT2-selective agonist CGP-42112. It is also blocked partly and in an additive fashion by the AT1- and AT2-selective antagonists losartan and PD-123319, indicating the contribution of both receptor subtypes to this response. AT1-dependent antiproliferation is selectively blocked by the cyclooxygenase inhibitor indomethacin and restored by prostaglandin E2, whereas AT2-receptor-mediated inhibition of growth is suppressed by the tyrosine phosphatase inhibitors orthovanadate and bpV(pic). Both pathways are, however, pertussis toxin sensitive. We hypothesize that, in fasciculata cells, the AT1 receptor inhibits bFGF-induced proliferation by stimulating prostaglandin synthesis, whereas the AT2 receptor mediates its effect through a pathway that requires protein tyrosine phosphatase activation.

Extensive nodular sarcoidosis in the hand

We report an atypical case of nodular sarcoidosis involving both hands. The pattern of extensive involvement of all digits with lesions extending into the pulp spaces has not been reported previously. The diagnosis of sarcoidosis should be considered even in patients presenting with clinically uncharacteristic manifestations.

ACTH angiotensin II and TGF beta participate in the regulation of steroidogenesis in bovine adrenal glomerulosa cells

Bovine zona glomerulosa cells, on the first day of culture, produce aldosterone as their major steroid with no detectable cortisol secretion. Continuous incubation with ACTH had no effect on aldosterone production nor on aldosterone synthase activity. This treatment resulted in a dose and time dependent rise in 17 alpha-hydroxylase activity, in parallel with an increase in cytochrome P-450(17 alpha) (CYP17) protein and mRNA. We have previously shown that TGF beta 1 is a potent inhibitor of differentiated functions of bovine fasciculata-reticularis cells and that CYP17 and AII receptors are the major targets explaining this effect. The present study examined whether 17 alpha-hydroxylase activity in glomerulosa cells could be regulated by angiotensin II (AII) and transforming growth factor-beta 1 (TGF beta 1). AII inhibits the induction of CYP17 by ACTH in a dose dependent manner. TGF beta 1 also blocks almost completely the stimulatory effect of ACTH. In order to suppress the endogenous action of TGF beta 1, incubations were performed with an anti-TGF beta antibody. This specific antibody induces the expression of CYP17 resulting in increased activity and mRNA levels. These results show that AII is able to modulate the expression of CYP17 in adrenal glomerulosa cells following ACTH stimulation. Furthermore, TGF beta 1 exerts an autocrine effect on the differentiation of glomerulosa cells through a regulatory loop repressing CYP17 activity.