Beyond the prothrombotic transcript of RPs: alternative splicing and circular RNAs

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): German Center for Cardiovascular Research (DZHK)

Background/Introduction

RPs are young, hyper-reactive and RNA-rich platelets. They have a pro-thrombotic potential, are predictors of an insufficient response to antiplatelet therapy after myocardial infarction and are suggested to play a key role in patients with chronic coronary syndrome (CCS) and high on-treatment platelet reactivity. Moreover, RPs are promising novel biomarkers for the prediction of adverse cardiovascular events in different pathological settings.

Purpose

We aimed to compare for the first time the transcriptomic profiles of RPs and MPs in CCS patients.

Method

Using fluorescent activated cell sorting (FACS), we isolated RPs and MPs based on their RNA content from peripheral blood of 19 CCS patients. After sorting, RNA was extracted and quality, concentration and integrity were assessed with the Tapestation 4200 platform (Agilent). TotalRNA libraries were prepared, multiplexed and sequenced on a NextSeq 500 Illumina platform obtaining 80 to 100 million paired-end reads per sample. RNA-sequencing analysis was performed with R and DESeq2, a cut-off of p <0.005 and a log2fc >1 was applied. Alternative splicing event detection and analysis was performed with MAJIQ. We performed circular RNA (circRNA) analysis using CIRCexplorer.

Results

With total RNA-sequencing, we detected 1589 genes differentially expressed with 1100 transcripts upregulated in RPs, while 489 were enriched in MPs (Figure 1 A and B). In particular, transcripts for the collagen receptor GP6 (log2FC 1.12, p=6.89x10-41), thrombin receptor PAR4 (F2RL3, log2FC 1.1, p=3.54*10-21) and Von Willebrand Factor (log2FC 1.2, p value 1.26*10-38) were significantly enriched in RPs. We found an enrichment in MPs of transcript coding for genes involved in RNA processing such as the splicing regulator LUC7L3 (log2FC -1.01, p value 6.65*10-22). We detected several splicing events differentially regulated: an alternative splicing on the transcript GP6 is upregulated in RPs (Figure 1C); by the G-protein GNAQ transcript, one alternative splicing event was found upregulated in RPs, while two others were upregulated in MPs. Additionally, we detected an enrichment of the total level of circular RNAs in MPs compared to RPs (Figure 1E). Nevertheless, several circular RNAs that have not been described before were found enriched in RPs (Figure 1F).

Conclusion

This study represents the first transcriptomic profiling of RPs and MPs in patients with CCS and provides for the first time a biological explanation of RPs’ hyper-reactivity. The clear upregulation of prothrombotic signaling in RPs could provide and explanation to their hyperactivity and their correlation with cardiovascular events in different pathological settings. Altogether, these findings shed light on a new therapeutic niche in CCS patients. Nonetheless, the detrimental role of RPs in patients with coronary artery disease requires further investigations

Deep proteome profiling of mature and reticulated platelets in patients with chronic coronary syndrome using mass cytometry

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by the German Center for Cardiovascular

Research (DZHK grant number Deutsches Zentrum für Herz-

Kreislaufforschung 81 × 3600606 to D.B.).

Abstract:

Background/Introduction

Reticulated platelets (RPs) are prothrombotic RNA-rich platelets suggested to be detrimental in patients with chronic coronary syndrome (CCS) and high on treatment platelet reactivity. In addition, circulating RPs levels are independent predictor for adverse cardiovascular events in CCS patients and other pathological settings. However, RPs biology still need to be investigated.

Purpose

We thought to investigate the RPs proteome on single-cell level at rest and after activation using time-of-flight mass cytometry (CyTOF).

Method

Thrombocytes from peripheral blood of 11 CCS patients were isolated, prepared for CyTOF and stained with a custom-made CyTOF-antibody panel of 20 antibodies targeting important transmembrane proteins (anti-CD9, anti-CD29, anti-CD31, anti-CD36-, anti-CD40, anti-CD41, anti-CD42a, anti-CD42b-, anti-CD47, anti-CD61, anti-CD62P-, anti-CD63, anti-CD69, anti-CD107a, anti-CD154, anti-GPVI, anti-GPIIbIIa complex, anti-Par1, anti-PEAR-1 and the negative control anti-CD3 coupled with different metal isotopes). Two samples were prepared from each patient: one baseline sample (non-stimulated platelets) and one sample stimulated with 10 μM thrombin receptor-activating peptide (TRAP). According to previous experiences and common practice, we detected RPs and mature platelets (MPs) based on their RNA content. We analyzed the results with a custom bioinformatic pipeline comparing RPs to MPs expression. Earth mover’s distance (EMD) was assed as a measure of differential expression.

Results

While our bioinformatic analysis revealed that all transmembrane markers are significantly higher expressed in the larger RPs compared to MPs, not all markers differ to the same extend. Interestingly, the four markers with the highest calculated EMD (values in brackets) are all key regulators of platelet activation and aggregation: the collagen receptor GPVI (34.18), the collagen integrin receptor unit CD29 (ITGB1: 33.17), the adhesion protein CD9 (32.94) and the von Willebrand receptor unit CD42b (GPIbalpha) (30.08) (Figure 1A).

Regarding the activation marker expression upon TRAP stimulation, RPs show higher median signal intensities of all four activation markers compared to MPs (Figure 1B and C). Especially, the markers CD107a (LAMP-1) and CD154 (CD40L) are expressed in MPs only to a very low extend, whereas there is a clear overexpression in RPs.

Conclusion

This dataset provides the first high resolution analysis of RPs proteome at rest and upon activation. The pro-thrombotic profile of RPs explains their hyperactivity and could offer the first biomolecular explanation of the detrimental role of RPs in CCS patients. In addition, this dataset provide high resolution biomolecular information which could be useful to personalize antiplatelet therapy in patients with high RPs levels.

Reticulated platelet mass cytometry reveals unexplored therapeutic targets in patients with chronic coronary syndrome

Background

Reticulated platelets (RPs) are young, hyper-reactive thrombocytes that contain more RNA compared with mature platelets (MPs). The measurement of RPs level in peripheral blood with point-of-care systems is fast, reproducible, and inexpensive. Elevated RPs in peripheral blood predict adverse events in patients with acute and chronic coronary syndrome through unknown mechanisms. Preliminary transcriptome analyses reported an enrichment of pro-thrombotic transcripts. However, proteomic analyses are not available, and the biological features of RPs are largely unknown.

Purpose

We aimed to perform the largest proteomic characterization of RPs using mass cytometry with single-cell resolution in patients with chronic coronary syndrome (CCS) undergoing dual antiplatelet therapy (DAPT).

Methods

Thrombocytes from peripheral blood of CCS patients were isolated, prepared for mass cytometry (CyTOF) and stained with a custom-made CyTOF-panel of 20 antibodies targeting important transmembrane proteins (anti-CD9, anti-CD29, anti-CD31, anti-CD36-, anti-CD40, anti-CD41, anti-CD42a, anti-CD42b-, anti-CD47, anti-CD61, anti-CD62P-, anti-CD63, anti-CD69, anti-CD107a, anti-CD154, anti-GPVI, antiGPIIb/GPIIIa complex, anti-Par1, anti-PEAR-1 and the negative control anti-CD3 coupled with different metal isotopes). Two samples were prepared from each donor: one baseline sample (non-stimulated platelets) and one sample stimulated with 10 μM thrombin receptor-activating peptide (TRAP). According to previous experiences and common practice, we detected RPs and MPs based on their RNA content. We analyzed the results with a custom bioinformatic pipeline.

Results

13 patients with CCS on DAPT were included in this study. Mass cytometry highlighted an expression heterogeneity of relevant transmembrane proteins in thrombocytes of CCS patients (Figure 1A-B colored according to expression level: from blue-low to red-high). CyTOF detected an upregulation of important transmembrane receptors in RPs compared to MPs in quiescent platelets: GPVI (p<0.0001), PAR-1 (p<0.0001), GPIX (p<0.0001), and GPIbα (p<0.0001, Figure 1C). After TRAP-stimulation, RPs expressed higher levels of the activation markers P-Selectin (p=0.0016) and LAMP-3 (CD63, p<0.0001) compared to MPs confirming RPs hyperactivity (Figure 1D).

Conclusion

We here describe the first biological proteomic characterization with single-cell resolution of RPs biology in CCS patients. The upregulation of the activation markers P-Selectin and LAMP-3 as well as of specific transmembrane proteins as the collagen receptor GPVI and the thrombin receptor PAR-1 in patients treated with DAPT (schematic overview in Figure 2) provides the first solid biomolecular explanation of RPs hyper-reactivity and involvement in cardiovascular disease. Moreover, these results offer unexplored therapeutic targets to tailor antiplatelet therapy based on platelet protein expression in patients with elevated RPs

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): German Center for Cardiovascular Research (DZHK) Figure 1. Platelet expressionFigure 2. Schematic overview

The pro-thrombotic transcriptomic signature of reticulated platelets in patients with chronic coronary syndrome

Introduction

Reticulated or immature platelets (RPs) are hyper-reactive young platelets that are larger and contain significantly more RNA compared to mature platelets (MPs). High levels of RPs in peripheral blood are predictors of an insufficient response to dual antiplatelet therapy and of adverse cardiovascular events in cardiovascular patients. Recently, we reported for the first time an enrichment of prothrombotic transcripts in RPs transcriptome of healthy donors. However, the biology of RPs in patients with coronary artery disease has not been investigated yet.

Purpose

We aimed to compare for the first time the transcriptomic profiles of RPs and MPs in patients with chronic coronary syndrome (CCS).

Methods

RPs and MPs from peripheral blood of CCS patients were isolated using fluorescent activated cell sorting (FACS) based on their RNA-content. After sorting, RNA was extracted and quality, concentration and integrity were assessed with the Tapestation 4200 platform (Agilent). Total-RNA libraries were prepared, multiplexed and sequenced on a NextSeq 500 Illumina platform obtaining 80 to 100 million paired-end reads per sample. RNA-sequencing analysis was performed with R and DESeq2.

Results

Total-RNA-sequencing detected 538 genes differentially expressed (300 downregulated, 238 upregulated) in RPs compared to MPs in CCS patients (Figure 1A). In particular, transcripts for the collagen receptor GP6 (FC 1.89, p=4.7x10–23), thrombin receptor PAR4 (F2RL3, FC 1.97, p=3.5x10–11), the ATP receptor P2RX1 (FC 1.94, p=3.1x10–15) and the ADP receptor P2RY1 (FC 1.82, p=3.15x10–10) were significantly enriched in RPs, whereas RNA regulators as the RISC-component TNRC6A (FC 0.5, p=7.98x10–13) and the splicing factor LUC7L3 (log2FC 0.55, p=1.76x10–11) were downregulated in RPs. Gene ontology analysis revealed an enrichment of relevant biological categories in RPs including “platelet activation” (fold enrichment = 10.5, p=1.8x10–8) and “blood coagulation” (fold enrichment = 4.4, p=2.4x10–3). Splicing analysis detected several differential splicing events. Of note, we detected an alternative splicing on GP6 transcript present only in RPs and absent in MPs (p=0.03, Figure 1B) At last, backsplicing analysis detected an enrichment of circular-RNAs in MPs.

Conclusions

This study represents the first deep transcriptomic profiling of RPs and MPs in patients with CCS and reports for the first time a differential enrichment of transcripts involved in platelet activation. Moreover, we could detect for the first time alternative splicing events in RPs and an enrichment of circular-RNAs in MPs. The clear upregulation of prothrombotic signaling in RPs (schematic overview Figure 1C) could explain, at least in part, their hyper-activity and their correlation with cardiovascular events in different pathological settings at it may offer a new therapeutic niche in patients with CCS.

Figure 1

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): German society of cardiology (DGK)

2181The prothrombotic transcriptome of reticulated platelets

Introduction

Reticulated platelets (RPs) are young, hyper-reactive platelets that are larger and contain significantly more RNA compared to older mature platelets. High levels of RPs in peripheral blood are predictors of an insufficient response to dual antiplatelet therapy in cardiovascular patients and of adverse cardiovascular events also in non-cardiac patients. However, the mechanisms underlying these correlations remains widely unknown and the biology of RPs has not been investigated yet.

Purpose

We aimed to compare for the first time the transcriptomic profiles of RPs and mature platelets (MPs).

Methods

RPs and MPs from peripheral blood of healthy donors were identified and isolated using FACS/Sorting based on their RNA-content. Immediately after sorting, RNA was extracted and quality, concentration and integrity was assessed with the Tapestation 4200 platform (Agilent). Total- and small-RNA libraries were prepared, multiplexed and sequenced on a NextSeq 500 Illumina platform

Results

Total-RNA-sequencing revealed 1744 differentially expressed genes (670 downregulated 1074 upregulated) in RPs compared to MPs (Figure 1A, B). In particular, transcripts for the collagen receptor GP6, thromboxane receptor A2 (TBXA2R), thrombin receptor PAR4 (F2RL3) and ATP receptor P2RX1 were significantly enriched in RPs, whereas several RNA regulators as the ribonuclease PARN, the RISC-component TNRC6A and the splicing factor LUC7L3 were downregulated in RPs. Gene ontology analysis revealed an enrichment of relevant biological categories in RPs including platelet activation and blood coagulation (Figure 1C). Gene Set Enrichment Analysis showed an enrichment of several activation pathways like thrombin, thromboxane and GPIIb/IIIa signaling in RPs. Small-RNA-sequencing reported 9 miRNAs significantly downregulated in RPs with targets involved in platelet reactivity.

Figure 1

Conclusions

This study represents the first comparative transcriptome analysis of RPs and MPs and reports for the first time a differential enrichment of transcripts involved in platelet activation. The clear upregulation of prothrombotic signaling in RPs could explain, at least in part, their hyper-activity and their correlation with cardiovascular events in different pathological settings (trancripts enriched in RPs: Figure 1D).

Acknowledgement/Funding

German Society of Cardiology (DGK Nr.102018) ESC First conctact initiative grant 2018

5-Hydroxymethylcytosine is an essential intermediate of active DNA demethylation processes in primary human monocytes

Background

Cytosine methylation is a frequent epigenetic modification restricting the activity of gene regulatory elements. Whereas DNA methylation patterns are generally inherited during replication, both embryonic and somatic differentiation processes require the removal of cytosine methylation at specific gene loci to activate lineage-restricted elements. However, the exact mechanisms facilitating the erasure of DNA methylation remain unclear in many cases.

Results

We previously established human post-proliferative monocytes as a model to study active DNA demethylation. We now show, for several previously identified genomic sites, that the loss of DNA methylation during the differentiation of primary, post-proliferative human monocytes into dendritic cells is preceded by the local appearance of 5-hydroxymethylcytosine. Monocytes were found to express the methylcytosine dioxygenase Ten-Eleven Translocation (TET) 2, which is frequently mutated in myeloid malignancies. The siRNA-mediated knockdown of this enzyme in primary monocytes prevented active DNA demethylation, suggesting that TET2 is essential for the proper execution of this process in human monocytes.

Conclusions

The work described here provides definite evidence that TET2-mediated conversion of 5-methylcytosine to 5-hydroxymethylcytosine initiates targeted, active DNA demethylation in a mature postmitotic myeloid cell type.

DNA methylation of the 5'-untranslated region at +298 and +351 represses BACE1 expression in mouse BV-2 microglial cells

BACE1, which cleaves the amyloid precursor protein, is the rate-limiting enzyme for β-amyloid peptide production, leading to the pathogenesis of Alzheimer's disease (AD). A high plasma level of homocysteine, acting as a potent methyltransferase inhibitor, is assumed to be a risk factor for AD onset. Using the demethylating drug 5-aza-2'-deoxycytidine (5-Aza), we tested whether and how BACE1 expression is regulated in mouse BV-2 microglial cells. 5-Aza increased both BACE1 mRNA and protein levels in a dose-dependent manner. Bisulfite-sequencing analysis revealed that two CpG sites at positions +298 and +351 in the 5'-untranslated region (5'-UTR) of the BACE1 gene were specifically demethylated in BV-2 cells treated with 5-Aza. In silico analysis showed that the +351 site is the STAT3/CTCF-binding site; the function of the +298 site has not been identified. To assess whether these two CpG sites play an important role in 5-Aza-induced transcriptional activation of BACE1, we constructed a BACE1 gene promoter including the 5'-UTR (-1136 to +500) fused to a CpG-free luciferase gene (pCpGL-BACE1) and its mutant pCpGL-BACE1-AA, which has substituted CG dinucleotides at the two CpG sites of pCpGL-BACE1 to AA. Promoter analysis showed a significant decrease (∼30%) in the activity of pCpGL-BACE1-AA compared with that of pCpGL-BACE1. Furthermore, in vitro methylation of these two reporter constructs showed a complete silencing of their promoter activities. Our data demonstrate that BACE1 gene expression is regulated by DNA methylation of at least two CpG sites at positions +298 and +351 in the 5'-UTR in BV-2 microglial cells.

Active DNA demethylation in human postmitotic cells correlates with activating histone modifications, but not transcription levels

Background

In mammals, the dynamics of DNA methylation, in particular the regulated, active removal of cytosine methylation, has remained a mystery, partly due to the lack of appropriate model systems to study DNA demethylation. Previous work has largely focused on proliferating cell types that are mitotically arrested using pharmacological inhibitors to distinguish between active and passive mechanisms of DNA demethylation.

Results

We explored this epigenetic phenomenon in a natural setting of post-mitotic cells: the differentiation of human peripheral blood monocytes into macrophages or dendritic cells, which proceeds without cell division. Using a global, comparative CpG methylation profiling approach, we identified many novel examples of active DNA demethylation and characterized accompanying transcriptional and epigenetic events at these sites during monocytic differentiation. We show that active DNA demethylation is not restricted to proximal promoters and that the time-course of demethylation varies for individual CpGs. Irrespective of their location, the removal of methylated cytosines always coincided with the appearance of activating histone marks.

Conclusions

Demethylation events are highly reproducible in monocyte-derived dendritic cells from different individuals. Our data suggest that active DNA demethylation is a precisely targeted event that parallels or follows the modification of histones, but is not necessarily coupled to alterations in transcriptional activity.

Lineage-specific DNA methylation in T cells correlates with histone methylation and enhancer activity

DNA methylation participates in establishing and maintaining chromatin structures and regulates gene transcription during mammalian development and cellular differentiation. With few exceptions, research thus far has focused on gene promoters, and little is known about the extent, functional relevance, and regulation of cell type-specific DNA methylation at promoter-distal sites. Here, we present a comprehensive analysis of differential DNA methylation in human conventional CD4(+) T cells (Tconv) and CD4(+)CD25(+) regulatory T cells (Treg), cell types whose differentiation and function are known to be controlled by epigenetic mechanisms. Using a novel approach that is based on the separation of a genome into methylated and unmethylated fractions, we examined the extent of lineage-specific DNA methylation across whole gene loci. More than 100 differentially methylated regions (DMRs) were identified that are present mainly in cell type-specific genes (e.g., FOXP3, IL2RA, CTLA4, CD40LG, and IFNG) and show differential patterns of histone H3 lysine 4 methylation. Interestingly, the majority of DMRs were located at promoter-distal sites, and many of these areas harbor DNA methylation-dependent enhancer activity in reporter gene assays. Thus, our study provides a comprehensive, locus-wide analysis of lineage-specific methylation patterns in Treg and Tconv cells, links cell type-specific DNA methylation with histone methylation and regulatory function, and identifies a number of cell type-specific, CpG methylation-sensitive enhancers in immunologically relevant genes.

Dap12 expression in activated microglia from retinoschisin-deficient retina and its PU.1-dependent promoter regulation

Several alterations in the expression of immune-related transcripts were identified recently in the degenerating retina of the retinoschisin knockout (Rs1h(-/Y)) mouse, including the strong expression of the adaptor protein Dap12. As Dap12 is found in leukocytes, we hypothesized that its disease-related expression may be confined to activated retinal microglia cells. To test this hypothesis, we established a procedure for isolation and culture of retinal microglia cells and performed genome-wide expression profiling from Rs1h(-/Y) and control microglia. While retaining their activated state in culture, ex vivo microglia expressed high levels of Dap12 and the transcription factor PU.1. The activation-dependent induction of Dap12 was also confirmed in the microglia cell line BV-2 following in vitro stimulation. To examine the transcriptional regulation of Dap12 further, macrophage cell lines were transfected with several Dap12 reporter constructs. Promoter deletion assays and site-directed mutagenesis experiments demonstrated an essential role of evolutionarily conserved PU.1 consensus sites in the proximal -104/+118 Dap12 promoter. In vitro and in vivo binding of PU.1 to this promoter region was demonstrated using EMSA and chromatin immunoprecipitation. Knockdown of PU.1 by RNA interference caused a significant reduction of endogenous Dap12 expression and re-expression, and activation of PU.1 in PU.1(-/-) progenitor cells induced Dap12 transcription. Taken together, our results indicate that activated microglia from degenerating retinae express high levels of Dap12 and PU.1, and PU.1 controls the myeloid-specific regulation of Dap12 directly and may also play a general role in microglia gene expression during retinal degeneration.

CCAAT enhancer-binding protein beta regulates constitutive gene expression during late stages of monocyte to macrophage differentiation

Human monocyte to macrophage differentiation is accompanied by pronounced phenotypical changes and generally proceeds in the absence of proliferation. The molecular events governing this process are poorly understood. Here, we studied the regulation of the macrophage-specific chitotriosidase (CHIT1) gene promoter to gain insights into the mechanisms of transcriptional control during the differentiation of human blood monocytes into macrophages. We used transient transfections to define a cell type-specific minimal promoter that was mainly dependent on a proximal C/EBP motif that bound multiple C/EBP factors in gel shift assays. In depth analysis of occupied promoter elements using in vivo footprinting and chromatin immunoprecipitation analyses demonstrated the differentiation-associated recruitment of C/EBPbeta and PU.1 at the proximal promoter in parallel with CHIT1 mRNA induction. Notably, the induction of C/EBPbeta promoter binding strongly correlated with increased nuclear levels of Thr-235-phosphorylated C/EBPbeta protein during the differentiation process, whereas C/EBPbeta mRNA and total protein expression remained relatively stable. Our data suggest an important constitutive gene regulatory function for C/EBPbeta in differentiated macrophages but not in human blood monocytes.

Functional analysis of promoter CpG methylation using a CpG-free luciferase reporter vector

Methylation of CpG dinucleotides within proximal promoters is often associated with transcriptional silencing. Methylation-dependent repression is well established for hypermethylated CpG island promoters that are characterized by a high density of CpG residues. The effect of CpG DNA methylation on CpG-poor promoters is less well characterized, probably due to the lack of convenient assay systems to test promoter activities in vitro. In this report, we describe a novel luciferase reporter vector, pCpGL, which completely lacks CpG dinucleotides and can be used to study the effect of promoter DNA methylation in transfection assays. Whereas a traditional reporter vector that contains a large number of backbone CpG residues significantly represses a CpG-free promoter when methylated, our new reporter vector is only repressed due to the presence of functionally important, methylated CpG residues. The pCpGL vector provides a useful tool to study the effects of CpG methylation on CpG-rich and CpG-poor promoters.

Genome-Wide Profiling of CpG Methylation Identifies Novel Targets of Aberrant Hypermethylation in Myeloid Leukemia

The methylation of CpG islands is associated with transcriptional repression and, in cancer, leads to the abnormal silencing of tumor suppressor genes. Because aberrant hypermethylation may be used as a marker for disease, a sensitive method for the global detection of DNA methylation events is of particular importance. We describe a novel and robust technique, called methyl-CpG immunoprecipitation, which allows the unbiased genome-wide profiling of CpG methylation in limited DNA samples. The approach is based on a recombinant, antibody-like protein that efficiently binds native CpG-methylated DNA. In combination with CpG island microarrays, the technique was used to identify >100 genes with aberrantly methylated CpG islands in three myeloid leukemia cell lines. Interestingly, within all hypermethylation targets, genes involved in transcriptional regulation were significantly overrepresented. More than half of the identified genes were absent in microarray expression studies in either leukemia or normal monocytes, indicating that hypermethylation in cancer may be largely independent of the transcriptional status of the affected gene. Most individually tested genes were also hypermethylated in primary blast cells from acute myeloid leukemia patients, suggesting that our approach can identify novel potential disease markers. The technique may prove useful for genome-wide comparative methylation analysis not only in malignancies.

Children with Fetal Alcohol Syndrome in North Dakota: a case control study utilizing birth certificate data

A retrospective case control study utilizing birth certificate data in a population of children with Fetal Alcohol Syndrome (FAS) or Fetal Alcohol Effect (FAE) and controls in North Dakota was completed. Using the North Dakota FAS registry, 97 cases of FAS and FAE aged birth-18 years of age were identified. The North Dakota Department of Vital Records then searched for the child's birth certificates. For each case child, four controls were selected from the birth records. The controls were of the same race, sex, month and county of birth as the cases. Birth certificates for 68 children were identified, 44 with FAS and 24 with FAE. When compared with the FAE group, the FAS group had lower birth weights and mothers who began prenatal care later in pregnancy. The FAS/FAE group combined had mothers who were older, were more likely to be unmarried, had less weight gain during pregnancy, started prenatal care later in pregnancy and had fewer prenatal visits compared to controls. The FAS/FAE children had lower birth weights and higher rates of sibling deaths. The use of birth certificate data is a useful data source to compare maternal, paternal and prenatal characteristics for a population of children with FAS/FAE.

Microspheres of chitosan/poly(vinylalcohol) incorporating tetrasulphonated copper (II) phthalocyanine: preparation and characterization

Tetrasulphonated copper (II) phthalocyanine (TCP), in the salt form, was incorporated into a blend of chitosan (CTS)/poly(vinylalcohol) (PVA) and microspheres were produced using the method of salt coacervation with (approximately 20% w/v) sodium sulphate. Spectroscopic analysis, DSC and TGA were carried out to characterize the form in which the macro-complex was immobilized in the blend. Alkaline treatment of the coagulating medium produces species which are more stable, but with a different morphology observed by scanning electronic microscopy (SEM). Microspheres coagulated in sodium sulphate and also in an alkaline salt medium (0.5 and 2.0 M NaOH) were exposed to a solution of the dye, methylene blue, at an initial concentration of 7 mg/l and maintained in contact for 14 h at 26 +/- 1 degrees C. The kinetic data revealed a decrease in the capacity of sorption of the microspheres that had received the alkaline treatment. It is proposed that the new morphology attributed to these species blocks some sites for complex formation, making them inaccessible to the dye.

Effects of pituitary hormones on the prostate

BACKGROUND

Although essential, androgens alone are not sufficient to induce normal growth and functionality of the prostate. Nonandrogenic hormones must also be involved in the proliferation of the prostate cancer cells which do not respond to antiandrogenic therapy and which thus become androgen-independent. Prolactin, but also growth hormone and luteinizing hormone, are potentially able to act on both normal and abnormal prostatic cells.

METHODS

In this review we summarize data from the literature concerning the physiological and pathological implications of prolactin, growth hormone, and luteinizing hormone on the prostate.

RESULTS

In rodent prostates, prolactin and growth hormone can induce a variety of effects independently of androgens (e.g., transactivation of certain genes, or synthesis of the major secretion products). Moreover, hyperprolactinemia is responsible for inflammation and dysplasia of the gland, while growth hormone promotes the development of prostate tumors in vivo in the mouse and rat. Growth hormone acts on the gland directly, through prostatic growth hormone receptors, and/or indirectly via the stimulation of insulin-like growth factor-I (IGF-I) synthesis in the liver. Luteinizing hormone receptor is expressed in rat and human prostates. Luteinizing hormone increases the amount of various transcripts in the rat prostate through an androgen-independent pathway.

CONCLUSIONS

Prolactin, growth hormone, and luteinizing hormone, alone or synergistically with androgens, play physiologically significant roles in the normal prostate. The involvement of these hormones in the development of benign prostatic hyperplasia and prostatic carcinoma is an issue that needs to be addressed.

Luteinizing hormone increases the abundance of various transcripts, independently of the androgens, in the rat prostate

Differential display analysis was carried out to find, in the rat prostate, genes that could be regulated by Luteinizing Hormone (LH), independently of the androgens. Hypophysectomized and castrated adult rats were treated with either LH, testosterone or saline. Regulated discrete bands have been eluted and reamplified. After Northern blotting, the levels of mRNA corresponding to 8 PCR fragments were significantly increased by LH treatment. None of these inserts were found to be induced by testosterone. One insert was subcloned, sequenced and identified as the ribosomial protein S 23. A competitive RT-PCR assay was carried out on the full length S 23 cDNA and confirmed that its mRNA levels were stimulated by LH but not by testosterone. These results strongly suggest that the LH membrane receptor, previously shown to be expressed in the rat prostate, has a physiological significance in this organ. Moreover, it appears that the effect of LH on the rat prostate are independent of the androgens.

Genesis, a winged helix transcriptional repressor with expression restricted to embryonic stem cells

A novel member of the winged helix (formerly HNF-3/Forkhead) transcriptional regulatory family, termed Genesis, was isolated and characterized. Putative translation of the complete cDNA revealed the winged helix DNA binding domain to be centrally located within the protein, with regions on either side that contain known transcriptional regulatory motifs. Extensive Northern analysis of Genesis found that the message was exclusively expressed in embryonic stem cells or their malignant equivalent, embryonal carcinoma cells. The Genesis transcript was down-regulated when these cells were stimulated to differentiate. DNA sequences that Genesis protein would interact with were characterized and were found to contain a consensus similar to that found in an embryonic stem cell enhancer sequence. Co-transfection experiments revealed that Genesis is a transcriptional repressor. Genesis mapped to mouse chromosome 4 in a region syntenic with human chromosome 1p31, a site of nonrandom abnormalities in germ cell neoplasia, neuroblastoma, and acute lymphoblastic leukemia. Genesis is a candidate for regulating the phenotype of normal or malignant embryonic stem cells.

Growth hormone directly affects the function of the different lobes of the rat prostate

In this study, we investigated the involvement of GH in rat prostate function. First, we demonstrated that specific transcripts corresponding to the GH receptor (4.5 kilobases) and to the GH-binding protein (1.2 kilobases) were expressed in the normal rat prostate, but also in all prostatic carcinoma cell lines tested (LNCaP, PC-3, MAT-Lu, MAT-LyLu, and Pif-1). Moreover, these transcripts were much more abundant in the human and rat carcinoma cells than in the normal tissue. One-year-old dwarf rats were supplemented for 7 days with saline (group DR1) or highly purified rat GH (group DR2). Northern blotting and quantitation of prostatic messenger RNAs (mRNAs) revealed that GH increases the steady state levels of transcripts coding for androgen receptor (2.4-fold), type I and II 5 alpha-reductases (2.6- and 2.2-fold), and several androgen-dependent proteins [prostatein C3 subunit (3.6-fold), probasin (11.0-fold), and R. W. B. (Royal Winnipeg Ballet) (12.5-fold)]. This suggests that GH might either potentiate the action of androgens on the prostate or act directly on this gland by a mechanism that does not depend on testicular androgens. To address this question, we supplemented hypophysectomized and castrated adult rats for 7 days with saline (group HC1), rat GH (group HC2), testosterone propionate (group HC3), or GH plus testosterone (group HC4), starting 3 days after castration. In this animal model, the abundance of C3 mRNA increased in all hormone-treated rats; the stimulation factors were 3.5 (group HC2), 25.5 (group HC3), and 9.5 (group HC4) compared to group HC1. Analysis of prostatein synthesis by Western blotting confirmed these results at the protein level. The same trend was observed for probasin and RWB mRNA levels. Probasin mRNA increased 4.5-fold in group HC2 and 12-fold in group HC3, but did not increase in group HC4 (both hormones combined); enhancement of RWB mRNA was, respectively, 5.0-, 28.0-, and 15.0-fold in groups HC2, HC3, and HC4. GH did not affect the abundance of androgen receptor mRNA. As described previously, the level of this mRNA dropped significantly in group HC3. GH alone did not significantly alter the level of either 5 alpha-reductase mRNA, whereas testosterone, alone or with GH, produced a 2-fold increase in type II 5 alpha-reductase mRNA (groups HC3 and HC4). Type I isoenzyme mRNA reached 1.6 times the control level (group HC1) in groups HC3 and HC4.(ABSTRACT TRUNCATED AT 400 WORDS)

Androgen-independent effects of prolactin on the different lobes of the immature rat prostate

In this study, we have examined the respective roles of androgens and prolactin (Prl) on rat prostate development and function. Hypophysectomized immature rats, castrated or not after hypophysectomy and treated or not with a 5 alpha-reductase inhibitor, were used to study the different aspects of Prl action on the rat prostate and its synergy with androgens in vivo. Using Northern blot analysis and quantitation of prostatic mRNAs, we have shown that Prl significantly increases the steady-state levels of transcripts coding for several lobe-specific proteins: the C3 subunit of prostatein, probasin, and RWB. We have confirmed these observations in vitro, on explants of immature rat prostate treated with either saline, Prl, or testosterone. In addition, we have demonstrated by a nuclear run-on assay that Prl significantly enhances the transcription rate of the C3 gene in the rat prostate. We conclude that the effects of Prl concern all lobes of the organ and are, at least in part, androgen-independent. Moreover, Prl is able, via an androgen-independent pathway, to increase the rate of transcription of the C3 gene, one of the major products of the rat prostate.

Intracellular Ca2+ and Ca(2+)-binding proteins in chemically transformed rat fibroblasts

Disturbed Ca2+ handling and altered levels of Ca(2+)-binding proteins (CaBPs) have been found in many transformed cells. To investigate whether there exists a correlation between expression of CaBPs and intracellular Ca2+ we analyzed three transformed rat fibroblast cell lines (T14, T10, and T43) exhibiting different levels of CaBPs. All three cell lines express calmodulin (CaM) at elevated levels compared to normal tissues. In addition, oncomodulin (OM) is expressed at high levels in T14 cells and at much lower levels in T10 cells, while T43 cells do not express OM. We demonstrate that CaBP levels are affected by changes of extracellular [Ca2+] ([Ca2+]o). In reduced [Ca2+]o, CaM levels were increased up to 60%, while OM levels were decreased up to 65% in T14 and T10 cells. Increase of [Ca2+]o, on the other hand, led to a decrease of CaM levels and an increase of OM levels, suggesting that [Ca2+]o exerts its effect on OM and CaM differently. Comparison of the growth rates in reduced [Ca2+]o revealed that T14 cells with the most pronounced CaM increase induced by low [Ca2+]o grew best under these conditions. These results indicate that elevated CaM expression but not the presence of OM reduces the Ca2+ requirement for growth. Intracellular [Ca2+] transients are not buffered by the high concentration of CaBPs in T14 cells. In contrast, [Ca2+]i transients induced by increase of [Ca2+]o or addition of serum were most pronounced in T14 cells compared to T10 and T43 cells.

Reduction in the calcium requirement for growth is correlated with intracellular calcium stores in normal and SV40-transformed NIH 3T3 cells

Untransformed NIH 3T3 cells do not proliferate in media with reduced calcium, while SV40-transformed NIH 3T3 cells do. Intracellular calcium stores of untransformed cells were depleted to a higher extent than those of transformed cells under these conditions, which led to a decreased intracellular calcium transient in response to serum, compared to SV40-transformed cells. Furthermore, untransformed cells could be gradually adapted to proliferate in the low-calcium medium and, after adaptation, maintained their stores and serum response in low calcium media. Our experiments indicate that it is the ability of the cells to maintain adequate calcium stores in low calcium media that correlates with a full serum response and the ability to proliferate, rather than any differences reflected in alterations of resting calcium levels.

An extract from Hydra vulgaris (Cnidaria) nematocysts increases cytoplasmic Ca2+ levels in fibroblasts

It was previously shown that a toxic protein present in an extract prepared from nematocysts of Hydra vulgaris (Cnidaria) is highly hemolytic and induces spasms in test animals (Klug et al., 1989, Toxicon 27, 325). We now demonstrate that this nematocyst extract affects cell viability and induces an increase of cytosolic Ca2+ concentration as measured in fura-2 loaded single fibroblasts. This increase is caused by Ca2+ entering from the external medium and the effect appears to be due to the hemolytic component of the venom.

Stress computed tomography analysis of the distal radioulnar joint: a diagnostic tool for determining translational motion

Sixteen distal radioulnar joints in eight normal volunteers (five females, three males) were evaluated by use of a special stress computed tomography technique. The mean palmar and dorsal translational motion was 2.2 millimeters +/- 1.6 and 1.0 millimeters +/- 0.9, respectively, for the combined group. The mean stress range was 3.3 millimeters +/- 1.4 for the entire group. There was no statistical difference for the amount of motion noted on palmar stress, dorsal stress, and the stress-range between males and females. There was also no statistical difference between contralateral sides and hand dominance. The average contralateral difference was 0.1 millimeters, 0.1 millimeters, and 0.3 millimeters for palmar, no stress, dorsal studies, respectively. We conclude the limits of maximal translational motion of the distal radioulnar joints can be determined by computed tomography stress analysis. Unilateral analysis allows the determination of frank instability. However, bilateral analysis allows the determination of frank instability, subluxation, and dynamic instability. This technique is useful in evaluating distal radioulnar joint stability.

Hemolytic and toxic properties of Hydra attenuata nematocysts

Crude extract prepared from isolated and purified nematocysts (stenoteles, desmonemes, isorhizas) of Hydra attenuata Pall. (Cnidaria, Hydrozoa) contains two main toxic proteins. The first is a hemolysin (100-200,000 mol.wt) which also causes initial spasmodic contractions in larval and adult specimens of Drosophila. Both, hemolytic and neurotoxic activities are inhibited by low concentrations of Triton X-100. The second protein (30-100,000 mol.wt), which is not susceptible to Triton causes long lasting paralysis leading to death of the test animals (LD50 approximately 5 mg crude nematocyst extract per kg). Neither of the toxins is identical with the previously described phospholipase.