Placenta: an old organ with new functions.

The transition from oviparity to viviparity and the establishment of feto-maternal communications introduced the placenta as the major anatomical site to provide nutrients, gases, and hormones to the developing fetus. The placenta has endocrine functions, orchestrates maternal adaptations to pregnancy at different periods of pregnancy, and acts as a selective barrier to minimize exposure of developing fetus to xenobiotics, pathogens, and parasites. Despite the fact that this ancient organ is central for establishment of a normal pregnancy in eutherians, the placenta remains one of the least studied organs. The first step of pregnancy, embryo implantation, is finely regulated by the trophoectoderm, the precursor of all trophoblast cells. There is a bidirectional communication between placenta and endometrium leading to decidualization, a critical step for maintenance of pregnancy. There are three-direction interactions between the placenta, maternal immune cells, and the endometrium for adaptation of endometrial immune system to the allogeneic fetus. While 65% of all systemically expressed human proteins have been found in the placenta tissues, it expresses numerous placenta-specific proteins, whose expression are dramatically changed in gestational diseases and could serve as biomarkers for early detection of gestational diseases. Surprisingly, placentation and carcinogenesis exhibit numerous shared features in metabolism and cell behavior, proteins and molecular signatures, signaling pathways, and tissue microenvironment, which proposes the concept of "cancer as ectopic trophoblastic cells". By extensive researches in this novel field, a handful of cancer biomarkers has been discovered. This review paper, which has been inspired in part by our extensive experiences during the past couple of years, highlights new aspects of placental functions with emphasis on its immunomodulatory role in establishment of a successful pregnancy and on a potential link between placentation and carcinogenesis.

Proteome profiling of human placenta reveals developmental stage-dependent alterations in protein signature.

INTRODUCTION: Placenta is a complex organ that plays a significant role in the maintenance of pregnancy health. It is a dynamic organ that undergoes dramatic changes in growth and development at different stages of gestation. In the first-trimester, the conceptus develops in a low oxygen environment that favors organogenesis in the embryo and cell proliferation and angiogenesis in the placenta; later in pregnancy, higher oxygen concentration is required to support the rapid growth of the fetus. This oxygen transition, which appears unique to the human placenta, must be finely tuned through successive rounds of protein signature alterations. This study compares placental proteome in normal first-trimester (FT) and term human placentas (TP). METHODS: Normal human first-trimester and term placental samples were collected and differentially expressed proteins were identified using two-dimensional liquid chromatography-tandem mass spectrometry. RESULTS: Despite the overall similarities, 120 proteins were differently expressed in first and term placentas. Out of these, 72 were up-regulated and 48 were down-regulated in the first when compared with the full term placentas. Twenty out of 120 differently expressed proteins were sequenced, among them seven showed increased (GRP78, PDIA3, ENOA, ECH1, PRDX4, ERP29, ECHM), eleven decreased (TRFE, ALBU, K2C1, ACTG, CSH2, PRDX2, FABP5, HBG1, FABP4, K2C8, K1C9) expression in first-trimester compared to the full-term placentas and two proteins exclusively expressed in first-trimester placentas (MESD, MYDGF). CONCLUSION: According to Reactome and PANTHER softwares, these proteins were mostly involved in response to chemical stimulus and stress, regulation of biological quality, programmed cell death, hemostatic and catabolic processes, protein folding, cellular oxidant detoxification, coagulation and retina homeostasis. Elucidation of alteration in protein signature during placental development would provide researchers with a better understanding of the critical biological processes of placentogenesis and delineate proteins involved in regulation of placental function during development.

Downregulation of miR-542-3p Contributes to Apoptosis Resistance in Dermal Fibroblasts from Systemic Sclerosis Patients via Survivin Overexpression.

Systemic sclerosis (SSc) is characterized by excessive production of collagens by fibroblasts that leads to vast fibrosis. Resistance to apoptosis is one of the possible underlying mechanisms of fibrosis in these patients. Survivinis involved in inhibition of apoptosis and aberrantly functions in SSc. Since dysregulation of survivin-targeting microRNAs (miRNAs) has frequently been observed in cancer and some autoimmune disorders, this study aimed to investigate their expression status in dermal fibroblasts from SSc patients. DiffuseSSc patients were selected according to American College of Rheumatology criteria. Isolated fibroblasts from 10 SSc and 10 healthy skin biopsies were cultured. After examining purity of the cells, mRNA and miRNAs extraction was performed followed by complementary DNA (cDNA) synthesis. Relative expressions ofsurvivin mRNA, miR-16-5p, miR-320a, miR-218-5p, miR-708-5p and miR-542-3p were analyzed using real time PCR. Survivin mRNA expression was significantly 1.85-fold upregulated in fibroblasts from SSc patients compared with healthy controls (p=0.046). Among the studied miRNAs, miR-542-3p expression was significantly decreased (p=0.033), while enhanced expression of miR-708-5p was observed in SSc fibroblasts (p=0.05) in comparison to healthy subjects. Downregulation of miR-542-3p significantly correlated with survivin overexpression (r=-0.45, p=0.049). Downregulation of miR-542-3p that is correlated with higher surviving expression levels might be a possible cause of apoptosis resistance in SSc fibroblasts, hence providing a new understanding of the disease pathogenesis.

Increased inflammatory responsiveness of peripheral blood mononuclear cells (PBMCs) to in vitro NOD2 ligand stimulation in patients with ankylosing spondylitis.

Background: Ankylosing spondylitis (AS) is a common debilitating rheumatic disease in which the innate immune components especially the Interleukin (IL)-23/IL-17 axis related genes play important role in its pathogenesis. Nucleotide binding oligomerization domain-containing protein (NOD)2, as an innate receptor, is critical for IL-23 production in cells. Therefore, we aimed to stimulate NOD2 signaling and study its effects on cytokine production in peripheral blood mononuclear cells (PBMC) of these patients. Methods: PBMCs from 18 patients with active AS and 18 healthy individuals were separated by Ficoll-Hypaque density gradient centrifugation and cultured in the presence of muramyl dipeptide (MDP), as NOD2 ligand. Quantitative expression analysis of NOD1, NOD2, RIPK2, SLC15A4, NLRP1, NLRP3, IL23A, IL17A, IL1B, and TNFA genes was performed using Real-time polymerase chain reaction (PCR). Finally, protein changes of IL23A and IL17A expression were validated using enzyme linked immunosorbent assay (ELISA). Results: Apart from NOD1 that tend to be downregulated in the controls, all the selected genes showed overexpression in response to MDP in cells from the studied groups. Except RIPK2, all the genes had higher expression changes upon MDP stimulation in the AS population. Overexpression of IL23A and IL17A were confirmed at protein levels using ELISA. The strong positive correlation between NLRP3 and NOD2 was decreased after stimulation but new correlations between NLRP3 and IL1B, RIPK2 and SLC15A4 were observed after treatment. Conclusions: This study indicated that AS PBMCs were hyper-responsive to MDP stimulation. This observation implies an important role of NOD2 in the pathogenesis of inflammatory diseases including AS.

Role of innate immune system in the pathogenesis of ankylosing spondylitis.

Ankylosing Spondylitis (AS) is a debilitating rheumatic disease that gives young adults a severe form of arthritis with pain and stiffness in the axial skeleton. After the discovery of Human leukocyte antigen B27 (HLA-B27), several hypotheses have been suggested to uncover the exact etiology of AS. The tendency of HLA-B27 to form unusual structures results in recognition and activation of crucial components in innate immune system. Moreover, cellular and soluble arms of the innate response are frequently observed within the affected tissues. Genome-wide analysis has also shown the association of several innate immune-related pathways and cytokines, which act as the effective therapeutic targets in AS. Given the importance of innate immune system, we present a general overview of innate immune components and their involvement in the pathogenesis of AS. In our belief, this kind of explanation can hopefully provide new perspectives for diagnosis and treatment of these patients in the future.