Expression of the estrogen receptors and steroidogenic enzymes involved in estradiol formation in the monkey vagina.

OBJECTIVE: Estrogens are well recognized to have beneficial effects on vulvovaginal atrophy because of menopause. The distribution of estrogen receptors and enzymes responsible for estradiol (E2) formation within the vagina may provide insight into how dehydroepiandrosterone, a precursor of both estrogens and androgens, improves vulvovaginal atrophy. STUDY DESIGN: The purpose of the study was to determine where the steroidogenic enzymes responsible for E2 formation as well as estrogen receptors are localized in vaginal specimens collected from cynomolgus monkeys (Macaca fascicularis), the closest model to the human. HSD3B1, HSD17B1, HSD17B5, HSD17B12, aromatase (CYP19A1), estrogen receptor (ER)-α, and ER-ß were measured or localized by quantitative real-time polymerase chain reaction, immunohistochemistry, and immunofluorescence. Estrogens were quantified by liquid chromatography/tandem mass spectrometry. RESULTS: All steroidogenic enzymes and estrogen receptors are localized mainly in the superficial layer of the stratified squamous epithelium, blood vessel walls, and muscle fibers of the vagina. Immunolabeling of HSD17B5 and HSD17B12 shows that these enzymes are uniformly distributed from the basal membrane to the superficial keratinized cells, whereas HSD3B1 and aromatase are particularly localized in the outer (external) portion of the epithelial layer. ER-α and ER-ß are also distributed within the vaginal epithelium, with expression especially elevated at the basal membrane level. CONCLUSION: The enzymes responsible for E2 formation as well as ERs are expressed mainly in the superficial layer of the stratified epithelium as well as the muscle layer of the vagina. The present data provide morphologic and biochemical support for the role of local dehydroepiandrosterone transformation into estrogens in regulating epithelial cell maturation, pH, fluid secretion, smooth muscle activity, and blood flow regulation in the primate vagina.

Localization of the androgen-synthesizing enzymes, androgen receptor, and sex steroids in the vagina: possible implications for the treatment of postmenopausal sexual dysfunction.

INTRODUCTION: To better understand the mechanisms underlying the beneficial effects of the intravaginal administration of dehydroepiandrosterone (DHEA) observed in postmenopausal women on sexual dysfunction. AIMS: To identify the distribution of the androgen-synthesizing enzymes as well as androgen receptor (AR) and measure steroid levels in the monkey vagina. METHODS: The cynomolgus monkey (Macaca fascicularis), the closest model to the human, has been used to measure the expression levels of steroidogenic enzymes and androgen receptor by quantitative reverse transcription polymerase chain reaction (n=4), confirmed by immunohistochemistry, and immunofluorescence (n=3). DHEA and its androgenic metabolites were quantified by LC-MS/MS (n=4). MAIN OUTCOME MEASURES: The presence of SRD5A1, SRD5A2, HSD17B3, AR as well as nerve fibers (PGP 9.5) was investigated, and steroid levels were measured. RESULTS: AR is widely distributed within the vaginal epithelium and also in the lamina propria with a lower expression in the muscularis layer and blood vessel walls. Androgen-forming enzymes, on the other hand, are expressed in the vaginal stratified squamous epithelium at a relatively high level where they are uniformly distributed from the basal membrane up to the superficial keratinized cells. The enzymes are at a lower level in blood vessel walls and zona muscularis where nerve fibers are localized. DHEA and its androgen metabolites are present at biologically significant concentrations in the monkey vagina. CONCLUSION: The enzymes responsible for androgen formation as well as AR are at the highest level in the superficial layer of the stratified epithelium and muscularis layers of the vagina. These data provide a potential explanation for the described role of androgens in regulating vaginal lubrication, smooth muscle activity, blood flow, and the neuronal activity potentially involved in the correction of sexual dysfunction.

Interactions between prostaglandins, leukotrienes and HIV-1: possible implications for the central nervous system.

In HIV-1-infected individuals, there is often discordance between viremia in peripheral blood and viral load found in the central nervous system (CNS). Although the viral burden is often lower in the CNS compartment than in the plasma, neuroinflammation is present in most infected individuals, albeit attenuated by the current combined antiretroviral therapy. The HIV-1-associated neurological complications are thought to result not only from direct viral replication, but also from the subsequent neuroinflammatory processes. The eicosanoids - prostanoids and leukotrienes - are known as potent inflammatory lipid mediators. They are often present in neuroinflammatory diseases, notably HIV-1 infection. Their exact modulatory role in HIV-1 infection is, however, still poorly understood, especially in the CNS compartment. Nonetheless, a handful of studies have provided evidence as to how these lipid mediators can modulate HIV-1 infection. This review summarizes findings indicating how eicosanoids may influence the progression of neuroAIDS.

Leukotrienes inhibit early stages of HIV-1 infection in monocyte-derived microglia-like cells.

BACKGROUND: Microglia are one of the main cell types to be productively infected by HIV-1 in the central nervous system (CNS). Leukotriene B4 (LTB4) and cysteinyl-leukotrienes such as LTC4 are some of the proinflammatory molecules produced in infected individuals that contribute to neuroinflammation. We therefore sought to investigate the role of leukotrienes (LTs) in HIV-1 infection of microglial cells. METHODS: To evaluate the role of LTs on HIV-1 infection in the CNS, monocyte-derived microglial-like cells (MDMis) were utilized in this study. Leukotriene-treated MDMis were infected with either fully replicative brain-derived HIV-1 isolates (YU2) or R5-tropic luciferase-encoding particles in order to assess viral production and expression. The efficacy of various steps of the replication cycle was evaluated by means of p24 quantification by ELISA, luciferase activity determination and quantitative real-time polymerase chain reaction (RT-PCR). RESULTS: We report in this study that virus replication is reduced upon treatment of MDMis with LTB4 and LTC4. Additional experiments indicate that these proinflammatory molecules alter the pH-independent entry and early post-fusion events of the viral life cycle. Indeed, LT treatment induced a diminution in integrated proviral DNA while reverse-transcribed viral products remained unaffected. Furthermore, decreased C-C chemokine receptor type 5 (CCR5) surface expression was observed in LT-treated MDMis. Finally, the effect of LTs on HIV-1 infection in MDMis appears to be mediated partly via a signal transduction pathway involving protein kinase C. CONCLUSIONS: These data show for the first time that LTs influence microglial cell infection by HIV-1, and may be a factor in the control of viral load in the CNS.

Acquisition of host-derived CD40L by HIV-1 in vivo and its functional consequences in the B-cell compartment.

Aberrant activation of the B-cell compartment and hypergammaglobulinemia were among the first recognized characteristics of HIV-1-infected patients in the early 1980s. It has been demonstrated previously that HIV-1 particles acquire the costimulatory molecule CD40L when budding from activated CD4(+) T cells. In this paper, we confirmed first that CD40L-bearing virions are detected in the plasma from untreated HIV-1-infected individuals. To define the biological functions of virus-associated CD40L and fully characterize its influence on the activation state of B cells, we conducted a large-scale gene expression analysis using microarray technology on B cells isolated from human tonsillar tissue. Comparative analyses of gene expression profiles revealed that CD40L-bearing virions induce a highly similar response to the one observed in samples treated with a CD40 agonist, indicating that virions bearing CD40L can efficiently activate B cells. Among modulated genes, many cytokines/chemokines (CCL17, CCL22), surface molecules (CD23, CD80, ICAM-1), members of the TNF superfamily (FAS, A20, TNIP1, CD40, lymphotoxin alpha, lymphotoxin beta), transcription factors and associated proteins (NFKB1, NFKBIA, NFKBIE), second messengers involved in CD40 signaling (TRAF1, TRAF3, MAP2K1, phosphatidylinositol 3-kinase), and the activation-induced cytidine deaminase (AID) were identified. Moreover, we show that soluble factors induced upon the exposure of B cells to CD40L-bearing virions can exert chemoattractant properties toward CD4(+) T cells. We thus propose that a positive feedback loop involving CD40L-bearing HIV-1 particles issued from CD4(+) T cells productively infected with HIV-1 play a role in the virus-induced dysfunction of humoral immunity by chronically activating B cells through sustained CD40 signaling.

Novel 5-lipoxygenase isoforms affect the biosynthesis of 5-lipoxygenase products.

5-Lipoxygenase (5-LO) is the essential enzyme for the biosynthesis of leukotrienes, important mediators of inflammation. This study investigated whether variants of 5-LO exist in human leukocytes. 5-LO mRNA isoforms that are consistent with alternative splicing were identified by RT-PCR in a cell line or cell type-specific pattern. All evaluated cells expressed mRNA containing all 14 exons of 5-LO with the expected splicing sites. Individual isoforms that retained intron 10 (α-10), lacked exon 13 (Δ-13), and lacked exons 10 and 13 (Δ-10,13) or that lacked the first 96 base pairs of exon 10 (Δ-p10) were identified. Immunoreactive bands coeluting with the cloned α-10 and Δ-13 isoforms were measured in primary neutrophils and in Raji cells. When expressed in HEK293 cells, alternative proteins were without catalytic activity. However, when coexpressed with the active full-length 5-LO, alternative isoforms significantly decreased the biosynthesis of 5-LO products by up to 44%, as assessed by reverse-phase HPLC analysis. Additionally, in stimulated neutrophils the full-length active 5-LO was detected by immunoblot in both nuclear and non-nuclear compartments, while the Δ-13 isoform was only detected in the nuclear fraction. These alternative 5-LO isoforms may represent a new mechanism for the regulation of the 5-LO pathway and lipid mediator biosynthesis.

Accurate and sensitive liquid chromatography/tandem mass spectrometry simultaneous assay of seven steroids in monkey brain.

BACKGROUND: Following its secretion mainly by the adrenal glands, dehydroepiandrosterone (DHEA) acts primarily in the cells/tissues which express the enzymes catalyzing its intracellular conversion into sex steroids by the mechanisms of intracrinology. Although reliable assays of endogenous serum steroids are now available using mass spectrometry (MS)-based technology, sample preparation from tissue matrices remains a challenge. This is especially the case with high lipid-containing tissues such as the brain. With the combination of a UPLC system with a sensitive tandem MS, it is now possible to measure endogenous unconjugated steroids in monkey brain tissue. METHODS: A Shimadzu UPLC LC-30AD system coupled to a tandem MS AB Sciex Qtrap 6500 system was used. RESULTS: The lower limits of quantifications are achieved at 250 pg/mL for DHEA, 200 pg/mL for 5-androstenediol (5-diol), 12 pg/mL for androstenedione (4-dione), 50 pg/mL for testosterone (Testo), 10 pg/mL for dihydrotestosterone (DHT), 4 pg/mL for estrone (E1) and 1 pg/mL for estradiol (E2). The linearity and accuracy of quality controls (QCs) and endogenous quality controls (EndoQCs) are according to the guidelines of the regulatory agencies for all seven compounds. CONCLUSION: We describe a highly sensitive, specific and robust LC-MS/MS method for the simultaneous measurement of seven unconjugated steroids in monkey brain tissue. The single and small amount of sample required using a relatively simple preparation method should be useful for steroid assays in various peripheral tissues and thus help analysis of the role of locally-made sex steroids in the regulation of specific physiological functions.

A rapid and sensitive UPLC-MS/MS method for the simultaneous quantification of serum androsterone glucuronide, etiocholanolone glucuronide, and androstan-3α, 17ß diol 17-glucuronide in postmenopausal women.

Quantification of steroidal glucuronide conjugates by the indirect methods of immunoassay and GC-MS/MS may underestimate some conjugates since hydrolysis is needed in sample processing. In the present work, a sensitive and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the simultaneous direct quantification of androsterone glucuronide, etiocholanolone glucuronide, and androstan-3α, 17ß diol 17-glucuronide in postmenopausal women's serum. The quantification limits are 0.1ng/mL for 3α-diol-17G and 4ng/mL for both ADT-G and Etio-G, respectively, with an extraction from 200µL serum while the total run time is less than 6min for all three glucuronides. In this method, solid phase extraction is used for sample preparation. The assay has been validated in compliance with EndoCeutics SOPs and FDA guidelines for bioanalytical method development and validation. The recovery of glucuronides in stripped serum is consistent with that in unstripped serum, where the average difference in stripped and unstripped is less than 10%. A linear regression model fits well the standard curves of all three compounds with R≥0.99 where the weighting factor is 1/X. Interday accuracy and CV for all levels of QCs are within the range of 15% in both stripped and unstripped serum while all calibration curves are within the range of 6% except for LLOQs, which are within the range of 9%. Other parameters have also been assessed such as selectivity, matrix, lipemic and hemolysis effects as well as stabilities in solution and matrix. Incurred sample reanalysis has been performed with a result of over 93% within 20% of the original values. This reliable, sensitive and fast method is ready for large-scale clinical sample assays.

A sensitive, simple and robust LC-MS/MS method for the simultaneous quantification of seven androgen- and estrogen-related steroids in postmenopausal serum.

Steroids were first analyzed by immunoassay-based methods followed by gas chromatography mass spectrometry (GC-MS or GC-MS/MS) with derivatization techniques since steroids are neutral and do not ionize at a high level using the electrospray ionization technique. We now report a validated liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantification of seven steroidal compounds, i.e., estradiol (E2), estrone (E1), testosterone (Testo), dihydrotestosterone (DHT), androst-5-ene-3ß, 17ß-diol (5-diol), dehydroepiandrosterone (DHEA) and androstenedione (4-dione). The system used is a UPLC-MS/MS (Qtrap 6500) system. With this method, the sample preparation is the combination of liquid-liquid extraction and a simple selective derivatization for only E1 and E2. This assay method is simple and practically eliminates potential contamination. Low quantification limits of 1pg/mL, 4pg/mL, 50pg/mL, 10pg/mL, 100pg/mL, 500pg/mL and 100pg/mL have been found, respectively for the steroids mentioned above. Without derivatization, DHT sensitivity can be as low as 4pg/mL with S/N≥5. A full validation has been performed for the seven compounds in compliance with GLP and FDA guidelines for bioanalytical method development and validation. Recovery of all seven compounds in unstripped serum is similar to that in stripped serum: 72.1-84.7% for E2, 83.6-94.5% for E1, 88.2-90.3% for Testo, 82.0-90.6% for DHT, 84.9-92.0% for 5-diol, 88.1-93.8% for DHEA and 86.2-90.3% for 4-dione, respectively. A good linearity is obtained with R>0.99 for each compound within its calibration range. Accuracies of all levels of QC are within the range of 15% for all seven compounds. The between day variation coefficients are 6.1-8.9% for the low limits of quantification of all seven compounds with 0.7-6.1% for higher levels of QCs for all seven compounds. All results of other test parameters similarly meet the acceptance criteria of EndoCeutics SOPs and FDA guidelines. By comparison of GC-MS/MS and LC-MS/MS data for six derivatized and nonderivatized free steroids, the present data show the crucial importance to use validated assays according to the FDA guidelines to increase specificity, precision and reliability of the absolute values associated with MS/MS-based assays. This method has already been applied to series of samples from clinical trials and is ready for wide clinical use.

WITHDRAWN: Sensitive and Accurate Simultaneous Measurement of Estrone, Estradiol, Dehydroepiandrosterone, Androst-5-ene-3 beta, 17 beta diol, Androstenedione, Testosterone and Dihydrotestosterone in Postmenopausal Women Serum by a Robust LC-MS/MS Validated Assay using a Single Sample Preparation Method.

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Exposure of human astrocytes to leukotriene C4 promotes a CX3CL1/fractalkine-mediated transmigration of HIV-1-infected CD4⁺ T cells across an in vitro blood-brain barrier model.

Eicosanoids, including cysteinylleukotrienes (cysLTs), are found in the central nervous system (CNS) of individuals infected with HIV-1. Few studies have addressed the contribution of cysLTs in HIV-1-associated CNS disorders. We demonstrate that conditioned medium from human astrocytes treated with leukotriene C4 (LTC4) increases the transmigration of HIV-1-infected CD4(+) T cells across an in vitro blood-brain barrier (BBB) model using cultured brain endothelial cells. Additional studies indicate that the higher cell migration is linked with secretion by astrocytes of CX3CL1/fractalkine, a chemokine that has chemoattractant activity for CD4(+) T cells. Moreover, we report that the enhanced cell migration across BBB leads to a more important CD4(+) T cell-mediated HIV-1 transfer toward macrophages. Altogether data presented in the present study reveal the important role that LTC4, a metabolite of arachidonic acid, may play in the HIV-1-induced neuroinvasion, neuropathogenesis and disease progression.