IL1ß-NFκß-Myocardin signaling axis governs trophoblast-directed plasticity of vascular smooth muscle cells.

Vascular smooth muscle cell (VSMC) plasticity is fundamental in uterine spiral artery remodeling during placentation in Eutherian mammals. Our previous work showed that the invasion of trophoblast cells into uterine myometrium coincides with a phenotypic change of VSMCs. Here, we elucidate the mechanism by which trophoblast cells confer VSMC plasticity. Analysis of genetic markers on E13.5, E16.5, and E19.5 in the rat metrial gland, the entry point of uterine arteries, revealed that trophoblast invasion is associated with downregulation of MYOCARDIN, α-smooth muscle actin, and calponin1, and concomitant upregulation of Smemb in VSMCs. Myocardin overexpression or knockdown in VSMCs led to upregulation or downregulation of contractile markers, respectively. Co-culture of trophoblast cells with VSMCs decreased MYOCARDIN expression along with compromised expression of contractile markers in VSMCs. However, co-culture of trophoblast cells with VSMCs overexpressing MYOCARDIN inhibited their change in phenotype, whereas, overexpression of transactivation domain deleted MYOCARDIN failed to elicit this response. Furthermore, the co-culture of trophoblast cells with VSMCs led to the activation of NFκß signaling. Interestingly, despite producing IL-1ß, trophoblast cells possess only the decoy receptor, whereas, VSMCs possess the IL-1ß signaling receptor. Treatment of VSMCs with exogenous IL-1ß led to a decrease in MYOCARDIN and an increase in phosphorylation of NFκß. The effect of trophoblast cells in the downregulation of MYOCARDIN in VSMCs was reversed by blocking NFκß translocation to the nucleus. Together, these data highlight that trophoblast cells direct VSMC plasticity, and trophoblast-derived IL-1ß is a key player in downregulating MYOCARDIN via the NFκß signaling pathway.

Cellular Prion protein moonlights vascular smooth muscle cell fate: Surveilled by trophoblast cells.

Uterine spiral artery remodeling (uSAR) is a hallmark of hemochorial placentation. Compromised uSAR leads to adverse pregnancy outcomes. Salient developmental events involved in uSAR are active areas of research and include (a) trophendothelial cell invasion into the spiral arteries, selected demise of endothelial cells; (b) de-differentiation of vascular smooth muscle cells (VSMC); and (c) migration and/or death of VSMCs surrounding spiral arteries. Here we demonstrated that cellular prion (PRNP) is expressed in the rat metrial gland, the entry point of spiral arteries with the highest expression on E16.5, the day at which trophoblast invasion peaks. PRNP is expressed in VSMCs that drift away from the arterial wall. RNA interference of Prnp functionally restricted migration and invasion of rat VSMCs. Furthermore, PRNP interacted with two migration-promoting factors, focal adhesion kinase (FAK) and platelet-derived growth factor receptor-ß (PDGFR-ß), forming a ter-molecular complex in both the metrial gland and A7r5 cells. The presence of multiple putative binding site of odd skipped related-1 (OSR1) transcription factor on the Prnp promoter was observed using in silico promoter analysis. Ectopic overexpression of OSR1 increased, and knockdown of OSR1 decreased expression of PRNP in VSMCs. Coculture of VSMCs with rat primary trophoblast cells decreased the levels of OSR1 and PRNP. Interestingly, PRNP knockdown led to apoptotic death in ~9% of VSMCs and activated extrinsic apoptotic pathways. PRNP interacts with TRAIL-receptor DR4 and protects VSMCs from TRAIL-mediated apoptosis. These results highlight the biological functions of PRNP in VSMC cell-fate determination during uteroplacental development, an important determinant of healthy pregnancy outcome.

Tipping the balance toward stemness in trophoblast: Metabolic programming by Cox6B2.

Metabolic effector(s) driving cell fate is an emerging concept in stem cell biology. Here we showed that Cytochrome C Oxidase Subunit 6B2 (Cox6B2) is essential to maintain the stemness of trophoblast stem (TS) cells. RNA interference of Cox6b2 resulted in decreased mitochondrial Complex IV activity, ATP production, and oxygen consumption rate in TS cells. Furthermore, depletion of Cox6b2 in TS cells led to decreased self-renewal capacity indicated by compromised BrdU incorporation, Ki67 staining, and decreased expression of TS cell genetic markers. As expected, the consequence of Cox6b2 knockdown was the induction of differentiation. TS cell stemness factor CDX2 transactivates Cox6b2 promoter in TS cells. In differentiated cells, Cox6b2 is post-transcriptionally regulated by two microRNAs, miR-322-5p and miR-503-5p, leading to its downregulation as demonstrated by the gain-in or loss of function of these miRNAs. Cox6b2 transcripts gradually rise in placental trophoblast gestation progresses in both mice and rats with predominant expression in labyrinthine trophoblast. Cox6b2 expression is compromised in the growth-restricted placenta of rats with reciprocal up-regulation of miR-322-5p and miR-503-5p. These data highlight the importance of Cox6B2 in the regulation of TS cell state and uncompromised placental growth.

Sequestration of eIF4A by angiomotin: A novel mechanism to restrict global protein synthesis in trophoblast cells.

Enrichment of angiomotin (AMOT) in the ectoplacental cone of E7.5 murine placenta prompted our investigation on the role of AMOT in trophoblast differentiation. We show here that AMOT levels increased in mouse placenta during gestation and also upon induction of differentiation in trophoblast stem cell ex vivo. Proteomic data unravelling AMOT-interactome in trophoblast cells indicated a majority of AMOT interactors to be involved in protein translation. In-depth analysis of AMOT-interactome led to identification of eukaryotic translation initiation factor 4A (eIF4A) as the most plausible AMOT interactor. Loss of function of AMOT enhanced, whereas, gain in function resulted in decline of global protein synthesis in trophoblast cells. Bioinformatics analysis evaluating the potential energy of AMOT-eIF4A binding suggested a strong AMOT-eIF4A interaction using a distinct groove encompassing amino acid residue positions 238 to 255 of AMOT. Co-immunoprecipitation of AMOT with eIF4A reaffirmed AMOT-eIF4A association in trophoblast cells. Deletion of 238 to 255 amino acids of AMOT resulted in abrogation of AMOT-eIF4A interaction. In addition, 238 to 255 amino acid deletion of AMOT was ineffective in eliciting AMOT's function in reducing global protein synthesis. Interestingly, AMOT-dependent sequestration of eIF4A dampened its loading to the m7 -GTP cap and hindered its interaction with eIF4G. Furthermore, enhanced AMOT expression in placenta was associated with intrauterine growth restriction in both rats and humans. These results not only highlight a hitherto unknown novel function of AMOT in trophoblast cells but also have broad biological implications as AMOT might be an inbuilt switch to check protein synthesis in developmentally indispensable trophoblast cells.

Nitric-Oxide Synthase trafficking inducer (NOSTRIN) is an emerging negative regulator of colon cancer progression.

BACKGROUND: NOSTRIN, abundantly expressed in colon, was reported to be anti-angiogenic, anti-invasive and anti-inflammatory. NOSTRIN expression was inversely related to survival of pancreatic ductal adeno-carcinoma patients. Yet its function and regulatory mechanism in CRC remains elusive. METHODS: NOSTRIN's influence on EMT of CRC cells were analysed using realtime PCR array containing the functional EMT-transcriptome followed by western blotting. Regulation of oncogenic potential of CRC cells by NOSTRIN was elucidated using soft agar colony formation, trans-well invasion, wound healing and colonosphere formation assays. Biochemical assays were used to reveal mechanism of NOSTRIN function. Human CRC tissue array was used to test NOSTRIN mark in control and CRC disease stages. RESULTS: We showed here that CRC cell lines with less NOSTRIN expression has more invasive and migratory potential. NOSTRIN affected EMT-associated transcriptome of CRC cells by down regulating 33 genes that were functionally annotated to transcription factors, genes important for cell growth, proliferation, migration, cell adhesion and cytoskeleton regulators in CRC cells. NOSTRIN over-expression significantly reduced soft agar colony formation, wound healing and cell invasion. In line with this, RNA interference of Nostrin enhanced metastatic potential of CRC cells. Furthermore, stable overexpression of NOSTRIN in CRC cell line not only curtailed its ability to form colonosphere but also decreased expression of stemness markers CD133, CD44 and EpCAM. NOSTRIN's role in inhibiting self-renewal was further confirmed using BrdU incorporation assay. Interestingly, NOSTRIN formed immune-complex with Cdk1 in CRC cells and aided in increase of inhibitory Y15 and T14 phosphorylation of Cdk1 that halts cytokinesis. These ex vivo findings were substantiated using human colon cancer tissue array containing cDNAs from patients' samples with various stages of disease progression. Significant decrease in NOSTRIN expression was found with initiation and progression of advanced colon cancer disease stages. CONCLUSION: We illustrate function of a novel molecule, NOSTRIN in curtailing EMT and maintenance of CRC cell stemness. Our data validates importance of NOSTRIN mark during onset and disease progression of CRC indicating its diagnostic potential.

Nitric-oxide synthase trafficking inducer is a pleiotropic regulator of endothelial cell function and signaling.

Endothelial nitric-oxide synthase (eNOS) and its bioactive product, nitric oxide (NO), mediate many endothelial cell functions, including angiogenesis and vascular permeability. For example, vascular endothelial growth factor (VEGF)-mediated angiogenesis is inhibited upon reduction of NO bioactivity both in vitro and in vivo Moreover, genetic disruption or pharmacological inhibition of eNOS attenuates angiogenesis during tissue repair, resulting in delayed wound closure. These observations emphasize that eNOS-derived NO can promote angiogenesis. Intriguingly, eNOS activity is regulated by nitric-oxide synthase trafficking inducer (NOSTRIN), which sequesters eNOS, thereby attenuating NO production. This has prompted significant interest in NOSTRIN's function in endothelial cells. We show here that NOSTRIN affects the functional transcriptome of endothelial cells by down-regulating several genes important for invasion and angiogenesis. Interestingly, the effects of NOSTRIN on endothelial gene expression were independent of eNOS activity. NOSTRIN also affected the expression of secreted cytokines involved in inflammatory responses, and ectopic NOSTRIN overexpression functionally restricted endothelial cell proliferation, invasion, adhesion, and VEGF-induced capillary tube formation. Furthermore, NOSTRIN interacted directly with TNF receptor-associated factor 6 (TRAF6), leading to the suppression of NFκB activity and inhibition of AKT activation via phosphorylation. Interestingly, TNF-α-induced NFκB pathway activation was reversed by NOSTRIN. We found that the SH3 domain of NOSTRIN is involved in the NOSTRIN-TRAF6 interaction and is required for NOSTRIN-induced down-regulation of endothelial cell proteins. These results have broad biological implications, as aberrant NOSTRIN expression leading to deactivation of the NFκB pathway, in turn triggering an anti-angiogenic cascade, might inhibit tumorigenesis and cancer progression.

Regulation of Transcription by Circular RNAs.

Circular RNAs (circRNAs) are a class of noncoding RNA that are present in wide variety of cells in various tissue types across species. They are non-polyadenylated, single-stranded, covalently closed RNAs. CircRNAs are more stable than other RNAs due to lack of 5' or 3' end leading to resistance to exonuclease digestion. The length of circRNAs varies from 1 to 5 exons with retention of introns in mature circRNAs with ~25% frequency. They are primarily found in the cytosol within the cell although the mechanism of their nuclear export remains elusive. However, there is a subpopulation of circRNAs that remain in the nucleus and regulate RNA-Pol-II-mediated transcription. Bioinformatic approaches mining RNA sequencing data enabled genome-wide identification of circRNAs. In mammalian genome over 20% of the expressed genes in cells and tissues can produce these transcripts. Owing to their abundance, stability, and diverse expression profile, circRNAs likely play a pivotal role in regulatory pathways controlling lineage determination, cell differentiation, and function of various cell types. Yet, the impact of circRNA-mediated regulation on various cell transcriptome remains largely unknown. In this chapter, we will review the regulatory effects of circRNAs in the transcription of their own or other genes. Also, we will discuss the association of circRNAs with miRNAs and RNA-binding proteins (RBPs), with special reference to Drosophila circMbl and their role as an "mRNA trap," which might play a role in its regulatory potential transcriptionally or posttranscriptionally.

Molecular determinants of epithelial mesenchymal transition in mouse placenta and trophoblast stem cell.

Trophectoderm cells of the blastocyst are the precursor of the placenta that is comprised of trophoblast, endothelial and smooth muscle cells. Since trophoectoderm cells are epithelial in nature, epithelial mesenchymal transition (EMT) of trophoblast stem (TS) cells might play pivotal role in placental morphogenesis. However, the molecular regulation of EMT during placental development and trophoblast differentiation still remained elusive. In this report, we sought to identify the molecular signature that regulates EMT during placental development and TS cell differentiation in mice. On E7.5 onwards the TS cells, located in the ectoplacental cone (EPC), rapidly divide and differentiate leading to formation of placenta proper. Using a real time PCR based array of functional EMT transcriptome with RNA from mouse implantation sites (IS) on E7.5 and E9.5, it was observed that there was an overall reduction of EMT gene expression in the IS as gestation progressed from E7.5 to E9.5 albeit the levels of EMT gene expression were substantial on both days. Further validation of array results using real time PCR and western blot analysis showed significant decrease in EMT-associated genes that included (a) transcription factors (Snai2, Zeb1, Stat3 and Foxc2), (b) extracellular matrix and cell adhesion related genes (Bmp1, Itga5, Vcan and Col3A1), (c) migration and motility- associated genes (Vim, Msn and FN1) and (d) differentiation and development related genes (Wnt5b, Jag1 and Cleaved Notch-1) on E9.5. To understand whether EMT is an ongoing process during placentation, the EMT-associated signatures genes, prevalent on E 7.5 and 9.5, were analysed on E12.5, E14.5 and E17.5 of mouse placenta. Interestingly, expression of these EMT-signature proteins were significantly higher at E12.5 though substantial expressions was observed in placenta with progression of gestation from mid- to late. To evaluate whether TS cells have the potential to undergo EMT ex vivo, TS cells were subjected to EMT induction, which was confirmed using morphological analysis and marker gene expression. Induction of EMT in TS cells showed similar gene expression profile of placental EMT. These results have broad biological implications, as inadequate mesenchymal transition leading to improper trophoblast-vasculogenic mimicry leads to placental pathophysiology and pregnancy failure.

Trans-differentiation of trophoblast stem cells: implications in placental biology.

Trophoblast invasion is a hallmark of hemochorial placentation. Invasive trophoblast cells replace the endothelial cells of uterine spiral arteries. The mechanism by which the invasive trophoblast cells acquire this phenotype is unknown. Here, we demonstrate that, during differentiation, a small population of trophoblast stem (TS) cells trans-differentiate into a hybrid cell type expressing markers of both trophoblast (TC) and endothelial (EC) cells. In addition, a compendium of EC-specific genes was found to be associated with TS cell differentiation. Using functional annotation, these genes were categorized into angiogenesis, cell adhesion molecules, and apoptosis-related genes. HES1 repressed transcription of EC genes in TS cells. Interestingly, differentiated TCs secrete TRAIL, but its receptor DR4 is expressed only in ECs and not in TCs. TRAIL induced apoptosis in EC but not in TC. Co-culture of ECs with TC induced apoptosis in ECs via extrinsic apoptotic pathway. These results highlight that (a) TS cells possess the potential to trans-differentiate into "trophendothelial" phenotype, regulated by HES1 and (b) trophoblast differentiation-induced TRAIL secretion directs preferential demise of ECs located in their vicinity.

Molecular regulation of trophoblast stem cell self-renewal and giant cell differentiation by the Hippo components YAP and LATS1.

BACKGROUND: Trophoblast stem cells (TSCs), the precursors of trophoblast cells of placenta, possess the potential to differentiate into various trophoblastic subtypes in vitro. Establishment of extraembryonic trophoblastic lineage is preceded by the "outside versus inside" positional information in preimplantation embryos, critically synchronized by the Hippo components. Abundant expression of Hippo effector YAP in TSCs and differentiated cells with paucity of information on Hippo regulation of TSC proliferation/differentiation led us test the hypothesis that Hippo dynamics is one of the regulators of  TSC proliferation/differentiation. METHODS: Blastocyst-derived murine TSCs were used. Dynamics of Hippo components were analyzed using immunofluorescence, western blotting, immunoprecipitation, qRT-PCR. Interaction studies were performed using full-length and deletion constructs. BrdU incorporation assay, flow cytometry-based polyploidy analysis and confocal microscopy were used to decipher the underlying mechanism. RESULTS: YAP translocates to the nucleus in TSCs and utilizes its WW2 domain to interact with the PPQY motif of the stemness factor, CDX2. YAP limits TSC proliferation with associated effect on CDX2 target CyclinD1. Trophoblast giant cells (TGC) differentiation is associated with cytoplasmic retention of YAP, heightened pYAPSer127, decrease in the level of the core Hippo component, LATS1, which thereby impedes LATS1-LIMK2 association. Decreased LATS1-LIMK2 complex formation in TGCs was associated with elevated pLIMK2Thr505 as well as its target pCOFILINSer3. Precocious overexpression of LATS1 during trophoblast differentiation decreased TGC marker, Prl2c2, diminished pLIMK2Thr505 and inactive COFILIN (pCOFILINSer3) while COFILIN-phosphatase, CHRONOPHIN remained unchanged. LATS1 overexpression inhibited trophoblast endoreduplication with smaller-sized TGC-nuclei, lower ploidy level and disintegrated actin filaments. Inhibition of LIMK2 activity recapitulated the effects of LATS1 overexpression in trophoblast cells. CONCLUSION: These results unveil a multilayered regulation of trophoblast self-renewal and differentiation by the Hippo components.

Protocol for functional characterization of endoreduplicated murine trophoblast cells.

Murine trophoblast stem cells (TSCs) have shaped placental research by providing resources for investigating trophoblast subtype specialization. Trophoblast giant cells (TGCs) are large polyploid cells, which undergo repetitive rounds of DNA replication without intervening mitosis by a process called endoreduplication. Endocrine and paracrine functions of TGCs aid in maternal adaptations to pregnancy. Here, we describe a protocol for in vitro differentiation of murine TSCs to TGCs together with the genotypic as well as phenotypic characterization of the endoreduplicated TGCs. For complete details on the use and execution of this protocol, please refer to Basak and Ain (2022).

MicroRNA regulation of murine trophoblast stem cell self-renewal and differentiation.

Proper placentation is fundamental to successful pregnancy. Placenta arises from differentiation of trophoblast stem (TS) cells during development. Despite being recognized as the counterpart of ES cells in placental development, the role of regulatory miRNAs in TS cell differentiation remains inadequately explored. Here, we have identified complete repertoire of microRNAs present in mouse trophoblast cells in proliferative and differentiated state. We demonstrated that two miRNA clusters, -290 and -322, displayed reciprocal expression during trophoblast differentiation. Loss of miR-290 cluster members or gain in miR-322 cluster members led to differentiation of TS cells. The trophoblast stemness factor, CDX2, transactivated the miR-290 cluster and Cyclin D1 MiR-290 cluster members repressed cell cycle repressors, P21, P27, WEE1, RBL2, and E2F7, in TS cells. MiR-322 cluster members repressed the cell cycle activators, CYCLIN D1, CYCLIN E1, CDC25B, and CDX2, to induce differentiation. Taken together, our findings highlight the importance of posttranscriptional regulation by conserved miRNA clusters that form a regulatory network with CDX2, cell cycle activators, and repressors in equipoising TS cell self-renewal and differentiation.

Molecular regulation of vascular smooth muscle cell phenotype switching by trophoblast cells at the maternal-fetal interface.

INTRODUCTION: Establishment of hemochorial placenta is associated with development and remodelling of uterine vasculature at the maternal fetal interface. This results in calibration of high resistance uterine arteries to flaccid low resistance vessels resulting in increased blood flow to the placenta and fetus in humans and rodents. Mechanisms underlying these remodelling events are poorly understood. In this report, we examine regulation of vascular remodelling using vascular smooth muscle cell (VSMC) phenotype switching as a primary parameter. METHODS: Cellular dynamics was assessed by Immunofluorescence, qRT-PCR, western blotting in timed pregnant rat tissue. In vitro co-culture of trophoblast cells with vascular smooth muscle cells was used to understand regulation mechanism. RESULTS: Analysis of cellular dynamics on days 13.5, 16.5 and 19.5 of gestation in the rat metrial gland, the entry point of uterine arteries, revealed that invasion of trophoblast cells preceded disappearance of VSMC α-SMA, a contractile state marker. Co-culture of VSMCs with trophoblast cells in vitro recapitulated trophoblast-induced de-differentiation of VSMCs in vivo. Interestingly, co-culturing with trophoblast cells activated PDGFRß signalling in VSMCs, an effect mediated by secreted PDGF-BB from trophoblast cells. Trophoblast cells failed to elicit its effect on VSMC de-differentiation upon inhibition of PDGFRß signalling using a selective inhibitor. Moreover, co-culturing with trophoblast cells also led to substantial increase in Akt activation and a modest increase in Erk phosphorylation in VSMCs and this effect was abolished by PDGFRß inhibition. DISCUSSION: Our results highlight that trophoblast cells direct VSMC phenotype switching and trophoblast derived PDGF-BB is one of the modulator.

Harnessing Autophagic Network Is Essential for Trophoblast Stem Cell Differentiation.

Differentiation of trophoblast stem (TS) cells into various cell lineages of the placenta during mammalian development is accompanied by dynamic changes in its proteome for exerting the highly specialized functions of various cell subtypes. In the present study, we demonstrate that the autophagic machinery, which includes proteins for initiation, vesicle nucleation, and autophagosome maturation are robustly upregulated during differentiation of TS cells. Interestingly, basal levels of autophagy were detectable in the developing mouse placenta as well as TS cells. However, autophagic flux was actively triggered by induction of differentiation evident from LC3 maturation. Formation of Beclin1, Vps34, and PIK3R4 ternary complex at the phagophore assembly site that is typically known to induce autophagy was also enhanced during differentiation. Degradation of the p62/SQSTM1 cargo protein and its colocalization with LC3, a mature autophagosome marker, was most prevalent in the trophoblast giant cells (TGCs) and negligible in other trophoblast cells at day 6 of differentiation. Furthermore, disruption of autophagy by impairing lysosomal fusion in TS cells before induction of differentiation led to a decrease in the giant cell and spongiotrophoblast cell markers Prl3d1, Prl2c2, Prl4a1, and Tpbpα upon differentiation. In addition, inhibition of autophagy was associated with a decrease in nuclear size of TGCs. Taken together, these data highlight that autophagy is a necessary prelude in commitment of trophoblast differentiation from the multipotent TS cells probably by regulating protein turnover at the onset of differentiation.

NOSTRIN: A novel modulator of trophoblast giant cell differentiation.

Differentiation-dependent expression of NOSTRIN in murine trophoblast cells prompted investigation on NOSTRIN's function in trophoblast differentiation. We show here that NOSTRIN levels increased in both mouse and rat placenta during gestation. NOSTRIN expression was not co-related to expression of eNOS precluding its eNOS mediated function. NOSTRIN transcripts were identified in trophoblast cells of the placenta, predominantly in trophoblast giant cells (TGC). Precocious over-expression of NOSTRIN during differentiation of trophoblast stem cells led to up-regulation of genetic markers associated with invasion (Prl4a1, Prl2a1) and TGC formation (Prl2c2, Prl3d1, Prl3b1). The functional consequence of NOSTRIN over-expression was increased TGC formation and trophoblast cell invasion. Furthermore, number of polyploid TGCs that arise by endoreduplication, were higher in presence of NOSTRIN. Early induction of NOSTRIN was associated with substantial decrease in G/F actin ratio and augmentation of N-WASP-Dynamin-NOSTRIN ternary complex formation that might be partially responsible for nucleation of actin filaments. NOSTRIN also formed a complex with Cdk1 and increased phosphorylation of T14 and Y15 residues that inhibits cytokinesis. Interestingly, SH3 domain deleted NOSTRIN was ineffective in eliciting NOSTRIN's function in differentiating trophoblast cells. These findings demonstrate that NOSTRIN potentiates trophoblast differentiation towards TGC trajectory that is critical for hemochorial placentation.

Dexamethasone-induced Intra-Uterine Growth Restriction impacts NOSTRIN and its downstream effector genes in the rat mesometrial uterus.

Intra-Uterine Growth Restriction (IUGR) is a major cause of fetal and neonatal mortality. Understanding the impact of IUGR on utero-placental gene expression is key to developing effective therapy. In this report we elucidated the impact of IUGR on NOSTRIN and its downstream effector gene expression in the utero-placental compartments. We showed here that induction of IUGR by maternal dexamethasone administration in rats led to up-regulation of NOSTRIN transcript and protein in the mesometrial triangle of the uterus (MG) and not in other utero-placental compartments as compared to control. This was associated with down-regulation of twelve genes and four cytokines that were known to be regulated by NOSTRIN and also required for maintenance of pregnancy. Interestingly, there was remarkable decrease in phosphorylation of RelA transcription factor in the MG during IUGR in line with the fact that the down regulated genes harbour RelA transcription activation domain in their promoters. Furthermore, HIF-1α level was reciprocal to NOSTRIN expression pattern in the mesometrial compartment during IUGR and also in CoCl2 treated endothelial cells. Over-expression of HIF-1α led to a decrease in NOSTRIN levels suggesting inhibition of Nostrin transcription by HIF-1α. Our findings highlight the importance of NOSTRIN in uterine pathophysiology during IUGR.

Sedative effect of Clozapine is a function of 5-HT2A and environmental novelty.

Antipsychotic drugs are the mainstay in the treatment of schizophrenia and bipolar disorder. However, antipsychotics often exhibit sedation or activity suppression among many other side effects, and the factors that influence them remain poorly understood. We now show, using a 5-HT2A knockout (Htr2a-/-) mouse, that environmental circumstances can affect suppression of activity induced by the atypical antipsychotic- Clozapine. We observed that Htr2a-/- mice were more resistant to Clozapine-induced suppression of activity (CISA) and this behaviour was dependent on the environment being 'novel'. In their 'home' environment, at identical doses the mice exhibited CISA. Interestingly, the effect of genotype and environmental novelty on CISA could not be extended to the other antipsychotics that were tested, i.e. Haloperidol and Risperidone. Haloperidol-induced activity suppression was independent of context and genotype. Whereas context affected Risperidone-induced activity suppression only in the Htr2a+/+ mice. Furthermore, we observed that caffeine, a stimulant, elicited resistance to CISA similar to that seen in the 'novel' context. Our study establishes a previously unknown interaction between the environmental context, 5-HT2A and CISA and emphasises the role of non-pharmacological factors such as environment on the effects of the drug, which seem antipsychotic-specific. Our findings should advance the understanding of the side effects of individual antipsychotics and the role of environment to overcome side effects such as sedation.

MicroRNA regulation of Transthyretin in trophoblast differentiation and Intra-Uterine Growth Restriction.

Placental trophoblast cells produce various cytokines, transporters vital to normal embryogenesis. Transthyretin (TTR) aids trans-placental passage of maternal thyroxin (TH) to fetal circulation. Inadequate TH delivery leads to developmental abnormality. Regulation of TTR biosynthesis in placenta is critical for normal embryo development. We showed here that TTR transcripts were expressed more in fetal placenta. Using bioinformatic analysis and confirmation with dual-luciferase reporter assays, we found that miR-200a-3p and miR-141-3p inhibited TTR expression by directly binding to the 3'UTR of TTR, which is reversed by mutation in the microRNA binding site. Differentiation of human trophoblast BeWo cells was associated with decreased TTR transcript and protein levels with concomitant increase in the levels of both microRNAs. Interestingly, ectopic overexpression of the microRNA mimics abrogated thyroxin uptake by BeWo cells, which was reversed by the corresponding inhibitors. Furthermore, in a rat model of intra-uterine growth restriction (IUGR), TTR expression decreased significantly in placenta with reciprocal rise in miR-141-3p but not 200a-3p. In human IUGR placenta, TTR transcript and protein levels were significantly lower associated with high expression of miR-141-3p but not 200a-3p. These data provides new insight into physiological role of miR-141-3p in regulating TTR during trophoblast differentiation and IUGR.

Phenotypic analysis of the rat placenta.

The rat is an important model for studying the biology of trophoblast-uterine development. This chapter describes methods that are useful for the characterization of the rat uteroplacental compartment.

Hypobaric hypoxia as a tool to study pregnancy-dependent responses at the maternal-fetal interface.

Establishment of proper oxygen and nutrient supply to the fetus is essential for a successful pregnancy. The maternal-fetal interface is the site of vascular modifications, providing a conduit for the delivery of essential nutrients to the developing fetus. Pregnancy-dependent adaptive vascular responses within the uteroplacental compartment can be exaggerated by exposure to a physiological stressor such as hypoxia. A simple procedure for exposing pregnant rats and mice to hypobaric hypoxia is presented.