Despite transcriptional and functional coordination, cyclooxygenase-2 and microsomal prostaglandin E synthase-1 largely reside in distinct lipid microdomains in WISH epithelial cells

Progesterone Receptor Signaling Selectively Modulates Cytokine-Induced Global Gene Expression in Human Cervical Stromal Cells

Preterm birth (PTB) is the leading cause of morbidity and mortality in infants <1 year of age. Intrauterine inflammation is a hallmark of preterm and term parturition; however, this alone cannot fully explain the pathobiology of PTB. For example, the cervix undergoes a prolonged series of biochemical and biomechanical events, including extracellular matrix (ECM) remodeling and mechanochemical changes, culminating in ripening. Vaginal progesterone (P₄) prophylaxis demonstrates great promise in preventing PTB in women with a short cervix (<25 mm). We used a primary culture model of human cervical stromal fibroblasts to investigate gene expression signatures in cells treated with interleukin-1β (IL-1β) in the presence or absence of P₄ following 17β-estradiol (17β-E₂) priming for 7–10 days. Microarrays were used to measure global gene expression in cells treated with cytokine or P₄ alone or in combination, followed by validation of select transcripts by semiquantitative polymerase chain reactions (qRT-PCR). Primary/precursor (MIR) and mature microRNAs (miR) were quantified by microarray and NanoString^® platforms, respectively, and validated by qRT-PCR. Differential gene expression was computed after data normalization followed by pathway analysis using Kyoto Encyclopedia Genes and Genomes (KEGG), Panther, Gene Ontology (GO), and Ingenuity Pathway Analysis (IPA) upstream regulator algorithm tools. Treatment of fibroblasts with IL-1β alone resulted in the differential expression of 1432 transcripts (protein coding and non-coding), while P₄ alone led to the expression of only 43 transcripts compared to untreated controls. Cytokines, chemokines, and their cognate receptors and prostaglandin endoperoxide synthase-2 (PTGS-2) were among the most highly upregulated transcripts following either IL-1β or IL-1β + P₄. Other prominent differentially expressed transcripts were those encoding ECM proteins, ECM-degrading enzymes, and enzymes involved in glycosaminoglycan (GAG) biosynthesis. We also detected differential expression of bradykinin receptor-1 and -2 transcripts, suggesting (prominent in tissue injury/remodeling) a role for the kallikrein–kinin system in cervical responses to cytokine and/or P₄ challenge. Collectively, this global gene expression study provides a rich database to interrogate stromal fibroblasts in the setting of a proinflammatory and endocrine milieu that is relevant to cervical remodeling/ripening during preparation for parturition.

Licofelone-DPPC Interactions: Putting Membrane Lipids on the Radar of Drug Development

(1) Background: Membrane lipids have been disregarded in drug development throughout the years. Recently, they gained attention in drug design as targets, but they are still disregarded in the latter stages. Thus, this study aims to highlight the relevance of considering membrane lipids in the preclinical phase of drug development. (2) Methods: The interactions of a drug candidate for clinical use (licofelone) with a membrane model system made of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) were evaluated by combining Langmuir isotherms, Brewster angle microscopy (BAM), polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS), and grazing-incidence X-ray diffraction (GIXD) measurements. (3) Results: Licofelone caused the expansion of the DPPC isotherm without changing the lipid phase transition profile. Moreover, licofelone induced the reduction of DPPC packing density, while increasing the local order of the DPPC acyl chains. (4) Conclusions: The licofelone-induced alterations in the structural organization of phosphatidylcholine monolayers may be related to its pharmacological actions. Thus, the combination of studying drug-membrane interactions with the pharmacological characterization that occurs in the preclinical stage may gather additional information about the mechanisms of action and toxicity of drug candidates. Ultimately, the addition of this innovative step shall improve the success rate of drug development.

Inflammatory gene networks in term human decidual cells define a potential signature for cytokine-mediated parturition

BACKGROUND

Inflammation is a proximate mediator of preterm birth and fetal injury. During inflammation several microRNAs (22 nucleotide noncoding ribonucleic acid (RNA) molecules) are up-regulated in response to cytokines such as interleukin-1β. MicroRNAs, in most cases, fine-tune gene expression, including both up-regulation and down-regulation of their target genes. However, the role of pro- and antiinflammatory microRNAs in this process is poorly understood.

OBJECTIVE

The principal goal of the work was to examine the inflammatory genomic profile of human decidual cells challenged with a proinflammatory cytokine known to be present in the setting of preterm parturition. We determined the coding (messenger RNA) and noncoding (microRNA) sequences to construct a network of interacting genes during inflammation using an in vitro model of decidual stromal cells.

STUDY DESIGN

The effects of interleukin-1β exposure on mature microRNA expression were tested in human decidual cell cultures using the multiplexed NanoString platform, whereas the global inflammatory transcriptional response was measured using oligonucleotide microarrays. Differential expression of select transcripts was confirmed by quantitative real time-polymerase chain reaction. Bioinformatics tools were used to infer transcription factor activation and regulatory interactions.

RESULTS

Interleukin-1β elicited up- and down-regulation of 350 and 78 nonredundant transcripts (false discovery rate < 0.1), respectively, including induction of numerous cytokines, chemokines, and other inflammatory mediators. Whereas this transcriptional response included marked changes in several microRNA gene loci, the pool of fully processed, mature microRNA was comparatively stable following a cytokine challenge. Of a total of 6 mature microRNAs identified as being differentially expressed by NanoString profiling, 2 (miR-146a and miR-155) were validated by quantitative real time-polymerase chain reaction. Using complementary bioinformatics approaches, activation of several inflammatory transcription factors could be inferred downstream of interleukin-1β based on the overall transcriptional response. Further analysis revealed that miR-146a and miR-155 both target genes involved in inflammatory signaling, including Toll-like receptor and mitogen-activated protein kinase pathways.

CONCLUSION

Stimulation of decidual cells with interleukin-1β alters the expression of microRNAs that function to temper proinflammatory signaling. In this setting, some microRNAs may be involved in tissue-level inflammation during the bulk of gestation and assist in pregnancy maintenance.

Discovery of HeLa Cell Contamination in HES Cells: Call for Cell Line Authentication in Reproductive Biology Research

Continuous cell lines are used frequently in reproductive biology research to study problems in early pregnancy events and parturition. It has been recognized for 50 years that many mammalian cell lines contain inter- or intraspecies contaminations with other cells. However, most investigators do not routinely test their culture systems for cross-contamination. The most frequent contributor to cross-contamination of cell lines is the HeLa cell isolated from an aggressive cervical adenocarcinoma. We report on the discovery of HeLa cell contamination of the human endometrial epithelial cell line HES isolated in our laboratory. Short tandem repeat analysis of 9 unique genetic loci demonstrated molecular identity between HES and HeLa cells. In addition, we verified that WISH cells, isolated originally from human amnion epithelium, were also contaminated with HeLa cells. Inasmuch as our laboratory did not culture HeLa cells at the time of HES cell derivations, the source of contamination was the WISH cell line. These data highlight the need for continued diligence in authenticating cell lines used in reproductive biology research.

Membrane prostaglandin E synthase-1: a novel therapeutic target

Prostaglandin E(2) (PGE(2)) is the most abundant prostaglandin in the human body. It has a large number of biological actions that it exerts via four types of receptors, EP1-4. PGE(2) is formed from arachidonic acid by cyclooxygenase (COX-1 and COX-2)-catalyzed formation of prostaglandin H(2) (PGH(2)) and further transformation by PGE synthases. The isomerization of the endoperoxide PGH(2) to PGE(2) is catalyzed by three different PGE synthases, viz. cytosolic PGE synthase (cPGES) and two membrane-bound PGE synthases, mPGES-1 and mPGES-2. Of these isomerases, cPGES and mPGES-2 are constitutive enzymes, whereas mPGES-1 is mainly an induced isomerase. cPGES uses PGH(2) produced by COX-1 whereas mPGES-1 uses COX-2-derived endoperoxide. mPGES-2 can use both sources of PGH(2). mPGES-1 is a member of the membrane associated proteins involved in eicosanoid and glutathione metabolism (MAPEG) superfamily. It requires glutathione as an essential cofactor for its activity. mPGES-1 is up-regulated in response to various proinflammatory stimuli with a concomitant increased expression of COX-2. The coordinate increased expression of COX-2 and mPGES-1 is reversed by glucocorticoids. Differences in the kinetics of the expression of the two enzymes suggest distinct regulatory mechanisms for their expression. Studies, mainly from disruption of the mPGES-1 gene in mice, indicate key roles of mPGES-1-generated PGE(2) in female reproduction and in pathological conditions such as inflammation, pain, fever, anorexia, atherosclerosis, stroke, and tumorigenesis. These findings indicate that mPGES-1 is a potential target for the development of therapeutic agents for treatment of several diseases.

Nuclear factor-kappa B regulates inducible prostaglandin E synthase expression in human amnion mesenchymal cells

The human amnion is a major intrauterine source of prostaglandin (PG) E(2), a potent mediator of uterine contractions and cervical ripening. During parturition, inflammatory cytokines promote PGE(2) production through increased prostaglandin-endoperoxide synthase-2 (PTGS2, also known as cyclooxygenase-2) expression. This is mediated, in part, through activation of the transcription factor nuclear factor kappa B (NFkappaB). Prostaglandin E synthase (PTGES, also known as microsomal PGE synthase-1) acts downstream of PTGS2 and is inducibly expressed in most systems. We hypothesized that NFkappaB might regulate cytokine-induced PTGES expression in amnion cells. With amnion mesenchymal cells, we found that proinflammatory cytokines coordinately upregulated PTGS2 and PTGES mRNA expression. In parallel, increased expression of the PTGS2 and PTGES proteins was observed. In comparison, the expression of two other PGE synthases (PTGES2 and PTGES3) was unmodified. PTGES induction was blocked both in the presence of pharmacological NFkappaB inhibitors and following adenovirus-mediated overexpression of a dominant-negative NFkappaB pathway protein. In cells transiently transfected with a luciferase reporter bearing a portion (-597/+33) of the human PTGES gene promoter, interleukin-1beta (IL1B) produced a moderate increase in luciferase activity; this effect was abrogated in the presence of an indirect NFkappaB inhibitor (MG-132). Finally, a kappaB-like regulatory element was identified that, when mutated, markedly attenuated IL1B-responsive PTGES promoter activity. In conclusion, our results support a role for NFkappaB in cytokine-induced PTGES expression in amnion mesenchymal cells in vitro. By coordinately regulating PTGS2 and PTGES, NFkappaB may contribute to an inducible PGE(2) biosynthesis pathway during human parturition.

Leukocyte lipid bodies regulation and function: contribution to allergy and host defense

Lipid bodies are lipid-rich organelles found in the cytoplasm of a variety of cells, including leukocytes. Lipid body morphology, its ability to interact with other organelles and its functions are dictated by its lipid arrangement, as well as its protein composition. Both may vary according to the cell type and with the specific lipid body biogenic stimulatory pathways. Nascent lipid bodies, which are formed in vivo in the course of a variety of immunopathological conditions, are sites of enzyme localization, eicosanoid production, as well as, sites for cytokine storage in inflammatory leukocytes, suggesting that lipid bodies function as inducible intracellular platforms for spatial segregation and organization of signaling leading to inflammatory mediator secretion during inflammation. The emerging role of lipid bodies as inflammatory organelles raises lipid body status to critical regulators of different inflammatory diseases, key markers of leukocyte activation and attractive targets for novel anti-inflammatory therapies.