Soren Hayrabedyan

Female sex steroid hormones modify some regulatory properties of monocyte-derived dendritic cells.

Monocyte‐derived dendritic cells (mDCs) are present in human decidua during the first month of pregnancy where they experience the effect of the increased concentration of progesterone (Pg) and estradiol (Estr). The aim of our study was to assess the effect of these reproductive hormones on the immunomodulatory role of mDCs.

Insight into PreImplantation Factor (PIF*) Mechanism for Embryo Protection and Development: Target Oxidative Stress and Protein Misfolding (PDI and HSP) through Essential RIPK Binding Site

Background Endogenous PIF, upon which embryo development is dependent, is secreted only by viable mammalian embryos, and absent in non-viable ones. Synthetic PIF (sPIF) administration promotes singly cultured embryos development and protects against their demise caused by embryo-toxic serum. To identify and characterize critical sPIF-embryo protein interactions novel biochemical and bio-analytical methods were specifically devised. Methods FITC-PIF uptake/binding by cultured murine and equine embryos was examined and compared with scrambled FITC-PIF (control). Murine embryo (d10) lysates were fractionated by reversed-phase HPLC, fractions printed onto microarray slides and probed with Biotin-PIF, IDE and Kv1.3 antibodies, using fluorescence detection. sPIF-based affinity column was developed to extract and identify PIF-protein interactions from lysates using peptide mass spectrometry (LC/MS/MS). In silico evaluation examined binding of PIF to critical targets, using mutation analysis. Results PIF directly targets viable cultured embryos as compared with control peptide, which failed to bind. Multistep Biotin-PIF targets were confirmed by single-step PIF-affinity column based isolation. PIF binds protein disulfide isomerases a prolyl-4-hydroxylase β-subunit, (PDI, PDIA4, PDIA6-like) containing the antioxidant thioredoxin domain. PIF also binds protective heat shock proteins (70&90), co-chaperone, BAG-3. Remarkably, PIF targets a common RIPK site in PDI and HSP proteins. Further, single PIF amino acid mutation significantly reduced peptide-protein target bonding. PIF binds promiscuous tubulins, neuron backbones and ACTA-1,2 visceral proteins. Significant anti-IDE, while limited anti-Kv1.3b antibody-binding to Biotin-PIF positive lysates HPLC fractions were documented. Conclusion Collectively, data identifies PIF shared targets on PDI and HSP in the embryo. Such are known to play a critical role in protecting against oxidative stress and protein misfolding. PIF-affinity-column is a novel utilitarian method for small molecule targets direct identification. Data reveals and completes the understanding of mechanisms involved in PIF-induced autotrophic and protective effects on the embryo.

miR‐204 is Dysregulated in Metastatic Prostate Cancer In Vitro

During cancer progression, the genome instability incurred rearrangement could possibly turn some of the tumor suppressor micro‐RNAs into pro‐oncogenic ones. We aimed to investigate miR‐204 in the context of prostate cancer progression using a cell line model of different levels of genome instability (LNCaP, PC3, VCaP and NCI H660), as demonstrated by the availability of ERG fusion. We studied the effect of miR‐204 modulation on master transcription factors important for lineage development, cell differentiation and prostate cancer bone marrow metastasis. We followed c‐MYB, ETS1 and RUNX2 transcript and protein expression and the miR‐204 affected global proteome. We further investigated if these transcription factors exert an effect on miR‐204 expression (qPCR, luciferase reporter assay) by silencing them using esiRNA. We found dualistic miR‐204 effects, either acting as a tumor suppressor on c‐MYB, or as an oncomiR on ETS1. RUNX2 and ETS1 regulation by miR‐204 was ERG fusion dependent, demonstrating regulatory circuitry disruption in advanced metastatic models. miR‐204 also differentially affected mRNA splicing and protein stability. miR‐204 levels were found dependent on cancer hypermethylation and supported by positive feedback induced by all three transcription factors. In this regulatory circuitry among miR‐204, c‐MYB, RUNX2 and ETS1, the c‐MYB was found to induce all three other members, but its expression was differentially affected by the methylation status in lymph node vs. bone metastasis. We demonstrate that not only tumor suppressor micro‐RNA loss, but also significant genome rearrangement‐driven regulatory loop perturbations play a role in the advanced cancer progression, conferring better pro‐survival and metastatic potential.

Sertoli Cell Quiescence - New Insights

It is currently accepted that the Sertoli cells are proliferatively active only during the embryogenesis and early fetal development, seizing to divide after puberty, when the spermatogenic niche is prepared, and they become terminally differentiated. So far, only seasonal breeders from mammals have been reported as having season‐dependent variations in adult Sertoli cells number and proliferation activity. In this review, we will try to shed light on testis somatic cell plasticity and discuss new evidence for some unique proliferative features Sertoli cells harbor.

PIF direct immune regulation: Blocks mitogen-activated PBMCs proliferation, promotes TH2/TH1 bias, independent of Ca2+

PreImplantation Factor (PIF(9&15)) secreted by viable embryos exerts an essential transplant acceptance and immune regulatory role in pregnancy. Synthetic PIF replicates endogenous PIFs effect in pregnant and non-pregnant immune disorder models. PIF binds macrophages to regulate CD3/CD28-induced T-cell response. We present evidence that PIF regulates the co-stimulatory T-cell receptor, CD2, which binds to and is activated by phytohemagglutinin (PHA), a potent mitogen, confirming PIFs ability to systemically respond to diverse immune stimulants. PIFs effect on PHA-activated PBMC (male and non-pregnant females) proliferation and cytokine secretion was tested, showing that both PIF(9&15) block PHA-induced PBMC proliferation and promote anti-inflammatory IL10 secretion, while reducing pro-inflammatory IFNγ secretion. Thus favoring a T(H)2 cytokine bias. Surface plasmon resonance spectroscopy, immunocytochemistry and Flex station experiments reveal that PIF effect is direct. PIF targets intracellular targets but does not affect early Ca(2+) mobilization. By promoting the CD2 receptor in activated T-cells and through inhibition of co-ligand CD58 expression, PIF regulates antigen-presenting cell (APC)-T-cell interactions required for PHA action. Structure-based design demonstrated that PIF15 offers improved target specificity as compared to PIF9. Collectively, PIF directly regulates mitogen-induced PBMC activation. Results support PIF translation for therapy of immune disorders.

PreImplantation factor (PIF*) regulates systemic immunity and targets protective regulatory and cytoskeleton proteins.

Secreted by viable embryos, PIF is expressed by the placenta and found in maternal circulation. It promotes implantation and trophoblast invasion, achieving systemic immune homeostasis. Synthetic PIF successfully transposes endogenous PIF features to non-pregnant immune and transplant models. PIF affects innate and activated PBMC cytokines and genes expression. We report that PIF targets similar proteins in CD14+, CD4+ and CD8+ cells instigating integrated immune regulation. PIF-affinity chromatography followed by mass-spectrometry, pathway and heatmap analysis reveals that SET-apoptosis inhibitor, vimentin, myosin-9 and calmodulin are pivotal for immune regulation. PIF acts on macrophages down-stream of LPS (lipopolysaccharide-bacterial antigen) CD14/TLR4/MD2 complex, targeting myosin-9, thymosin-α1 and 14-3-3eta. PIF mainly targets platelet aggregation in CD4+, and skeletal proteins in CD8+ cells. Pathway analysis demonstrates that PIF targets and regulates SET, tubulin, actin-b, and S100 genes expression. PIF targets systemic immunity and has a short circulating half-life. Collectively, PIF targets identified; protective, immune regulatory and cytoskeleton proteins reveal mechanisms involved in the observed efficacy against immune disorders.

Quantified Colocalization Reveals Heterotypic Histocompatibility Class I Antigen Associations on Trophoblast Cell Membranes: Relevance for Human Pregnancy

ABSTRACT Human placental syncytiotrophoblasts lack expression of most types of human leukocyte antigen (HLA) class I and class II molecules; this is thought to contribute to a successful pregnancy. However, the HLA class Ib antigens HLA-G, -E, and -F and the HLA class Ia antigen HLA-C are selectively expressed on extravillous trophoblast cells, and they are thought to play a major role in controlling feto-maternal tolerance. We have hypothesized that selective expression, coupled with the preferential physical association of pairs of HLA molecules, contribute to the function of HLA at the feto-maternal interface and the maternal recognition of the fetus. We have developed a unique analytical model that allows detection and quantification of the heterotypic physical associations of HLA class I molecules expressed on the membrane of human trophoblast choriocarcinoma cells, ACH-3P and JEG-3. Automated image analysis was used to estimate the degree of overlap of HLA molecules labeled with different fluorochromes. This approach yields an accurate measurement of the degree of colocalization. In both JEG-3 and ACH-3P cells, HLA-C, -E, and -G were detected on the cell membrane, while the expression of HLA-F was restricted to the cytoplasm. Progesterone treatment alone induced a significant increase in the expression level of the HLA-G/HLA-E association, suggesting that this heterotypic association is modulated by this hormone. Our data shows that the cell-surface HLA class I molecules HLA-G, -E, and -C colocalize with each other and have the potential to form preferential heterotypic associations.

Fundamental role of microRNAs in androgen-dependent male reproductive biology and prostate cancerogenesis.

Male reproductive failure has been linked to successive development of various urologic diseases including prostate cancer. There is strong epidemiologic data in support of this association, it is important therefore to identify the fundamental grounds that lay beneath such a connection. Male reproductive biology, as sex determined, is significantly dependent upon the hormonal regulation of androgens. With the advancement of knowledge on androgen receptivity and epigenetic regulation, the role of new regulatory factors such as microRNAs becomes essential. This review focuses on unraveling the role of microRNA tight incorporation in androgen‐dependent male reproductive biology in the context of recent prostate cancer data.

Key Cellular Components and Interactive Histocompatibility Molecules Regulating Tolerance to the Fetal Allograft

Implantation is a major landmark in life. It involves the correct apposition of the embryo in the maternal endometrium. The cellular environment influences placenta development, and direct contact of the fetus with maternal tissues is achieved through decidual cells. At the decidua, and at systemic level, the correct balance of cells potentially acting as antigen‐presenting cells and histocompatibility products play a pivotal role in achieving feto–maternal tolerance. Here, we review some of the current issues associated with the interplay between cells and molecules needed for pregnancy development.

Stem cells in the reproductive system.

This review article summarizes current knowledge on regulation, functions, and capacities of stem cells in the female and male reproductive tract. Major locations in which pluripotent cells reside and from where they can be isolated are the ovaries, the endometrium, the decidua, and the testis. They include oocytes, embryonic stem cells, trophoblast stem cells, and spermatogonial stem cells, but also several side populations, which can be obtained after certain isolation and culture procedures. The potential of pluripotent cells in the reproductive tract to differentiate is manifold, but heterogenous, depending upon their respective origin. As stem cells have a potential for future application in transplantation and regenerative medicine, this article also reviews the literature on major histocompatibility complex expression on stem cells of the reproductive tract, because of its immunogenic effects, but also because of its potential expression of HLA‐G, a potent immunomodulator mainly associated with trophoblast cells.