A Rho-associated coiled-coil containing kinases (ROCK) inhibitor, Y-27632, enhances adhesion, viability and differentiation of human term placenta-derived trophoblasts in vitro

In situ editing of tumour cell membranes induces aggregation and capture of PD-L1 membrane proteins for enhanced cancer immunotherapy

Immune checkpoint blockade (ICB) therapy has emerged as a new therapeutic paradigm for a variety of advanced cancers, but wide clinical application is hindered by low response rate. Here we use a peptide-based, biomimetic, self-assembly strategy to generate a nanoparticle, TPM1, for binding PD-L1 on tumour cell surface. Upon binding with PD-L1, TPM1 transforms into fibrillar networks in situ to facilitate the aggregation of both bound and unbound PD-L1, thereby resulting in the blockade of the PD-1/PD-L1 pathway. Characterizations of TPM1 manifest a prolonged retention in tumour ( > 7 days) and anti-cancer effects associated with reinvigorating CD8+ T cells in multiple mice tumour models. Our results thus hint TPM1 as a potential strategy for enhancing the ICB efficacy.

The Effects of Low Concentrations of Pravastatin on Placental Cells

Pravastatin is a promising medication to treat preeclampsia. However, the appropriate dose of pravastatin for managing preeclampsia has not been established. In this in vitro study, we examined the effects of low concentrations of pravastatin (0.01 to 10 µM) under hypoxic conditions on two types of placental cells and found that pravastatin decreased sFlt-1 levels up to 34% in cytotrophoblast cells isolated from human term placentas. Furthermore, we showed that sFlt-1 levels in HTR-8/SVneo cells, a cell line derived from first trimester trophoblast cells, decreased after exposure to very low concentrations of pravastatin (0.01, 0.1 µM). We also examined the effects of pravastatin on uterine spiral artery remodeling-related events and showed in wound healing and tube formation assays that low concentrations of pravastatin upregulated cell migration and invasion in HTR-8/SVneo cells. These results demonstrated that a low dose of pravastatin has in vitro effects that suggest a potential for anti-preeclamptic effects in vivo.

Isolation of pure primary term human cytotrophoblasts and their differentiation into syncytiotrophoblast-like cells as an ex vivo model of the human placenta

The placenta plays a fundamental role in fetal growth and maintenance of pregnancy. Its cellular components include a large multinucleated syncytiotrophoblast (STB) and its progenitor, cytotrophoblasts (CTBs), both of which perform vital functions in the human placenta. Primary cytotrophoblasts isolated from term human placentas that spontaneously fuse and differentiate into syncytiotrophoblast-like cells in vitro have been utilized to investigate the functions of the syncytiotrophoblast and placenta with multiple modifications. Although recent advances have enabled the use of trophoblast stem cell-derived organoids as a model for villous trophoblasts, primary CTBs offer several advantages, including spontaneous differentiation, easy access to materials (from term-delivered human placentas), and simple methodology. Here, we present a precise step-by-step process for isolating pure CTBs from term human placenta based on previously reported placenta digestion, density centrifugation, and CTB purification using anti-HLA-A, B, C antibody. Subsequently, we provide a method to improve CTB viability and differentiation into STB-like cells using epidermal growth factor (EGF) and a ROCK inhibitor (Y-27632) that ensures long-term and stable cultures without altering their proliferation. Because these cells can grow on standard tissue culture plates, this model can be easily utilized for various placental investigations, including innate immune responses, drug resistance, and STB metabolism. Employing this approach considerably enhances our understanding of placental functions, which are key to maternal and offspring health.

Highly parallel production of designer organoids by mosaic patterning of progenitors

Organoids derived from human stem cells are a promising approach for disease modeling, regenerative medicine, and fundamental research. However, organoid variability and limited control over morphological outcomes remain as challenges. One open question is the extent to which engineering control over culture conditions can guide organoids to specific compositions. Here, we extend a DNA "velcro" cell patterning approach, precisely controlling the number and ratio of human induced pluripotent stem cell-derived progenitors contributing to nephron progenitor (NP) organoids and mosaic NP/ureteric bud (UB) tip cell organoids within arrays of microwells. We demonstrate long-term control over organoid size and morphology, decoupled from geometric constraints. We then show emergent trends in organoid tissue proportions that depend on initial progenitor cell composition. These include higher nephron and stromal cell representation in mosaic NP/UB organoids vs. NP-only organoids and a "goldilocks" initial cell ratio in mosaic organoids that optimizes the formation of proximal tubule structures.

Cytoplasmic and nuclear DROSHA in human villous trophoblasts

In villous trophoblasts, DROSHA is a key ribonuclease III enzyme that processes pri-microRNAs (pri-miRNAs) into pre-miRNAs at the placenta-specific, chromosome 19 miRNA cluster (C19MC) locus. However, little is known of its other functions. We performed formaldehyde crosslinking, immunoprecipitation, and sequencing (fCLIP-seq) analysis of terminal chorionic villi to identify DROSHA-binding RNAs in villous trophoblasts. In villous trophoblasts, DROSHA predominantly generated placenta-specific C19MC pre-miRNAs, including antiviral C19MC pre-miRNAs. The fCLIP-seq analysis also identified non-miRNA transcripts with hairpin structures potentially capable of binding to DROSHA (e.g., SNORD100 and VTRNA1-1). Moreover, in vivo immunohistochemical analysis revealed DROSHA in the cytoplasm of villous trophoblasts. DROSHA was abundant in the cytoplasm of villous trophoblasts, particularly in the apical region of syncytiotrophoblast, in the full-term placenta. Furthermore, in BeWo trophoblasts infected with Sindbis virus (SINV), DROSHA translocated to the cytoplasm and recognized the genomic RNA of SINV. Therefore, in trophoblasts, DROSHA not only regulates RNA metabolism, including the biogenesis of placenta-specific miRNAs, but also recognizes viral RNAs. After SINV infection, BeWo DROSHA-binding VTRNA1-1 was significantly upregulated, and cellular VTRNA1-1 was significantly downregulated, suggesting that DROSHA soaks up VTRNA1-1 in response to viral infection. These results suggest that the DROSHA-mediated recognition of RNAs defends against viral infection in villous trophoblasts. Our data provide insight into the antiviral functions of DROSHA in villous trophoblasts of the human placenta.

Upregulation of autotaxin by oxidative stress via Nrf2 activation: A novel insight into the compensation mechanism in preeclamptic placenta

The response of autotaxin (ATX)-lysophosphatidic acid (LPA) signaling system to placental oxidative stress (OS) and its significance to preeclampsia were investigated. For this purpose, oxidative stress index (OSI) and ATX levels were measured in the serum of pregnant women with preeclampsia. The expression levels of ATX and LPA receptors were assessed in trophoblast cells under high OS and glucose deprivation/re-oxygenation (OGD/R) conditions, with particular emphasis on the antioxidative nuclear factor erythroid 2-related factor 2 (NRF2) pathway. The influence of ATX-LPA signaling on cell migration was also evaluated using the wound healing assay. ATX concentrations and OSI in the serum were found to be elevated in preeclamptic women. The serum ATX levels were also positively correlated with OSI. Trophoblast cells responded to OS by increasing ATX mRNA expression concomitantly with intranuclear translocation of Nrf2, whereas inhibition of Nrf2 activation reverted this effect. The ATX-LPA signaling pathway facilitated trophoblast cell motility after Nrf2 activation. In conclusion, OS accumulation in preeclamptic placenta may activate the ATX-LPA system in trophoblasts via the Nrf2 pathway to sustain trophoblast functionality.

Chloroquine is a safe autophagy inhibitor for sustaining the expression of antioxidant enzymes in trophoblasts

Inhibition of autophagy contributes to the pathophysiology of preeclampsia. Although chloroquine (CHQ) is an autophagy inhibitor, it can reduce the occurrence of preeclampsia in women with systemic lupus erythematosus. To clarify this important clinical question, this study aimed to address the safety of CHQ in trophoblast cells from the viewpoint of homeostasis, in which the anti-oxidative stress (OS) response and autophagy are involved. We used Western blotting to evaluate the protein levels in the trophoblast cells. The expression levels of heme oxygenase-1 (HO-1), an anti-OS enzyme, mediate resistance to OS induced by hydrogen peroxide (H₂O₂) in trophoblast cell lines. Among the autophagy modulators, bafilomycin A1 (BAF), an autophagy inhibitor, but not autophagy activators, suppressed HO-1 expression in BeWo cells; CHQ did not suppress HO-1 expression in BeWo cells. To clarify the role of autophagy in HO-1 induction, we observed no difference in HO-1 induction by H₂O₂ between autophagy-normal and autophagy-deficient cells. As for the mechanism of HO-1 induction by OS, BAF suppressed HO-1 induction by downregulating the expression of neighbor of BRCA1 gene 1 (NBR1) in the selective p62-NBR1-nuclear factor erythroid 2-related factor 2 (Nrf2) autophagy pathway. CHQ did not inhibit HO-1 expression by sustaining NBR1 expression in human villous tissues compared to BAF treatment. In conclusion, CHQ is a safer medicine than BAF for sustaining NBR1, which resist against OS in trophoblasts by connecting selective autophagy and the anti-OS response.

Actions of WNT family member 5A to regulate characteristics of development of the bovine preimplantation embryo†

WNT signaling is important for regulation of embryonic development. The most abundant WNT gene expressed in the bovine endometrium during the preimplantation period is WNT5A. One objective was to determine whether WNT5A regulates competence of the bovine preimplantation embryo to become a blastocyst and alters the number of cells in the inner cell mass and trophectoderm. A second objective was to delineate features of the cell-signaling mechanisms involved in WNT5A actions. WNT5A caused a concentration-dependent increase in the proportion of embryos developing to the blastocyst stage and in the number of inner cell mass cells in the resultant blastocysts. A concentration of 200 ng/mL was most effective, and a higher concentration of 400 ng/mL was not stimulatory. Bovine serum albumin in culture reduced the magnitude of effects of WNT5A on development to the blastocyst stage. WNT5A affected expression of 173 genes at the morula stage; all were upregulated by WNT5A. Many of the upregulated genes were associated with cell signaling. Actions of WNT5A on development to the blastocyst stage were suppressed by a Rho-associated coiled-coil kinase (ROCK) signaling inhibitor, suggesting that WNT5A acts through Ras homology gene family member A (RhoA)/ROCK signaling. Other experiments indicated that actions of WNT5A are independent of the canonical β-catenin signaling pathway and RAC1/c-Jun N-terminal kinase (JNK) signaling. This is the first report outlining the actions of WNT5A to alter the development of the mammalian embryo. These findings provide insights into how embryokines regulate maternal-embryonic communication.

ROCK Inhibitor (Y-27632) Abolishes the Negative Impacts of miR-155 in the Endometrium-Derived Extracellular Vesicles and Supports Embryo Attachment

Extracellular vesicles (EVs) are nanosized vesicles that act as snapshots of cellular components and mediate cellular communications, but they may contain cargo contents with undesired effects. We developed a model to improve the effects of endometrium-derived EVs (Endo-EVs) on the porcine embryo attachment in feeder-free culture conditions. Endo-EVs cargo contents were analyzed using conventional and real-time PCR for micro-RNAs, messenger RNAs, and proteomics. Porcine embryos were generated by parthenogenetic electric activation in feeder-free culture conditions supplemented with or without Endo-EVs. The cellular uptake of Endo-EVs was confirmed using the lipophilic dye PKH26. Endo-EVs cargo contained miR-100, miR-132, and miR-155, together with the mRNAs of porcine endogenous retrovirus (PERV) and β-catenin. Targeting PERV with CRISPR/Cas9 resulted in reduced expression of PERV mRNA transcripts and increased miR-155 in the Endo-EVs, and supplementing these in embryos reduced embryo attachment. Supplementing the medium containing Endo-EVs with miR-155 inhibitor significantly improved the embryo attachment with a few outgrowths, while supplementing with Rho-kinase inhibitor (RI, Y-27632) dramatically improved both embryo attachment and outgrowths. Moreover, the expression of miR-100, miR-132, and the mRNA transcripts of BCL2, zinc finger E-box-binding homeobox 1, β-catenin, interferon-γ, protein tyrosine phosphatase non-receptor type 1, PERV, and cyclin-dependent kinase 2 were all increased in embryos supplemented with Endo-EVs + RI compared to those in the control group. Endo-EVs + RI reduced apoptosis and increased the expression of OCT4 and CDX2 and the cell number of embryonic outgrowths. We examined the individual and combined effects of RI compared to those of the miR-155 mimic and found that RI can alleviate the negative effects of the miR-155 mimic on embryo attachment and outgrowths. EVs can improve embryo attachment and the unwanted effects of the de trop cargo contents (miR-155) can be alleviated through anti-apoptotic molecules such as the ROCK inhibitor.

Inhibition of YAP/TAZ-TEAD activity induces cytotrophoblast differentiation into syncytiotrophoblast in human trophoblast

During placentation, placental cytotrophoblast (CT) cells differentiate into syncytiotrophoblast (ST) cells and extravillous trophoblast (EVT) cells. In the placenta, the expression of various genes is regulated by the Hippo pathway through a transcription complex, Yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ)-TEA domain transcription factor (TEAD) (YAP/TAZ-TEAD) activity. YAP/TAZ-TEAD activity is controlled by multiple factors and signaling, such as cyclic AMP (cAMP) signaling. cAMP signaling is believed to be involved in the regulation of trophoblast function but is not yet fully understood. Here we showed that YAP/TAZ-TEAD expressions and their activities were altered by cAMP stimulation in BeWo cells, a human choriocarcinoma cell line. The repression of YAP/TAZ-TEAD activity induced the expression of ST-specific genes without cAMP stimulation, and transduction of constitutively active YAP, i.e., YAP-5SA, resulted in the repression of 8Br-cAMP-induced expressions of ST-specific genes in a TEAD-dependent manner. We also investigated the role of YAP/TAZ-TEAD in maintaining CT cells and their differentiation into ST and EVT cells using human trophoblast stem (TS) cells. YAP/TAZ-TEAD activity was involved in maintaining the stemness of TS cells. Induction or repression of YAP/TAZ-TEAD activity resulted in marked changes in the expression of ST-specific genes. Using primary CT cells, which spontaneously differentiate into ST-like cells, the effects of YAP-5SA transduction were investigated, and the expression of ST-specific genes was found to be repressed. These results indicate that the inhibition of YAP/TAZ-TEAD activity, with or without cAMP stimulation, is essential for the differentiation of CT cells into ST cells.

The Autophagy-Lysosomal Machinery Enhances Cytotrophoblast–Syncytiotrophoblast Fusion Process

Poor placentation is closely related with the etiology of preeclampsia and may impact fetal growth restriction. For placental developmental growth, we have demonstrated that dysregulation of autophagy, a key mechanism to maintain cellular homeostasis, in trophoblasts contributes to the pathophysiology of preeclampsia, a severe pregnancy complication, associated with poor placentation. It remains, however, unknown whether autophagy inhibition affects trophoblast syncytialization. This study evaluated the effect of autophagy in an in vitro syncytialization method using BeWo cells and primary human trophoblasts (PHT). In this study, we observed that autophagic activity decreased in PHT and BeWo cells during syncytialization. This decreased activity was accompanied by downregulation of the transcription factor, TFEB. Next, bafilomycin A1, an inhibitor of autophagy via suppressing V-ATPase in lysosomes, inhibited hCG production, CYP11A1 expression (a marker of differentiation), p21 expression (a senescence marker), and cell fusion in BeWo cells and PHT cells. Finally, LLOMe, an agent inducing lysosomal damage, also inhibited syncytialization and led to TFEB downregulation. Taken together, the autophagy-lysosomal machinery plays an important role in cytotrophoblast fusion, resulting in syncytiotrophoblasts. As autophagy inhibition contributed to the failure of differentiation in cytotrophoblasts, this may result in the poor placentation observed in preeclampsia.

25-hydroxycholesterol-induced cell death via activation of ROCK/LIMK/cofilin axis in colorectal cancer cell spheroids

25-Hydroxycholesterol (25OHC) induces anchorage-dependent programmed cell death, or anoikis, in colorectal cancer cells but the mechanism is not fully understood. Here, we found that 25OHC induced cofilin phosphorylation and promoted rearrangement of the actin cytoskeleton in spheroids of the colorectal cancer cell lines, DLD1 and HT29/WiDr. Cell death induced by 25OHC was inhibited by the actin polymerization inhibitor, cytochalasin D, and BMS-3, an inhibitor of LIMK, which phosphorylates and inactivates cofilin. In addition, we showed that cofilin phosphorylation induced by 25OHC was associated with caspase-3 activation, which can activate ROCK. Rho GTPase was directly activated by 25OHC. These results indicate that 25OHC affects actin dynamics through activation of the Rho/ROCK/LIMK/cofilin axis, eventuating in the cell death of colorectal cancer cell spheroids.

Suppression of human trophoblast syncytialization by human cytomegalovirus infection

INTRODUCTION

Placental dysfunction triggers fetal growth restriction in congenital human cytomegalovirus (HCMV) infection. Studies suggest that HCMV infection interferes with the differentiation of human trophoblasts. However, the underlying mechanisms have not been clarified. This study investigated the impact of HCMV infection on gene transcriptomes in cytotrophoblasts (CTBs) associated with placental dysfunction.

METHODS

CTBs were isolated from human term placentas, and spontaneous syncytialization was observed in vitro. The transcriptome profiles were compared between CTB groups with and without HCMV infection by cap analysis gene expression sequencing. The effect of HCMV infection on trophoblast differentiation was evaluated by examining cell fusion status using immunocytochemical staining for desmoplakin and assessing the production of cell differentiation markers, including hCG, PlGF, and soluble Flt-1, using ELISA.

RESULTS

The expression of the genes categorized in the signaling pathways related to the cell cycle was significantly enhanced in CTBs with HCMV infection compared with uninfected CTBs. HCMV infection hindered the alteration of the gene expression profile associated with syncytialization. This suppressive effect under HCMV infection was concurrent with the reduction in hCG and PlGF secretion. Immunostaining for desmoplakin revealed that HCMV infection reduced the cell fusion of cultured CTBs. These findings imply that HCMV infection has a negative impact on syncytialization, which is indispensable for the maintenance of villous function.

DISCUSSION

HCMV infection interferes with gene expression profiles and functional differentiation of trophoblasts. Suppression of syncytialization may be a survival strategy for HCMV to expand infection and could be associated with placental dysfunction.

The Differentiation of Pluripotent Stem Cells towards Endothelial Progenitor Cells - Potential Application in Pulmonary Arterial Hypertension

Background and Objectives

Endothelial progenitor cells (EPCs) and endothelial cells (ECs) have been applied in the clinic to treat pulmonary arterial hypertension (PAH), a disease characterized by disordered pulmonary vasculature. However, the lack of sufficient transplantable cells before the deterioration of disease condition is a current limitation to apply cell therapy in patients. It is necessary to differentiate pluripotent stem cells (PSCs) into EPCs and identify their characteristics.

Methods and Results

Comparing previously reported methods of human PSCs-derived ECs, we optimized a highly efficient differentiation protocol to obtain cells that match the phenotype of isolated EPCs from healthy donors. The protocol is compatible with chemically defined medium (CDM), it could produce a large number of clinically applicable cells with low cost. Moreover, we also found PSCs-derived EPCs express CD133, have some characteristics of mesenchymal stem cells and are capable of homing to repair blood vessels in zebrafish xenograft assays. In addition, we further revealed that IPAH PSCs-derived EPCs have higher expression of proliferation-related genes and lower expression of immune-related genes than normal EPCs and PSCs-derived EPCs through microarray analysis.

Conclusions

In conclusion, we optimized a highly efficient differentiation protocol to obtain PSCs-derived EPCs with the phenotypic and molecular characteristics of EPCs from healthy donors which distinguished them from EPCs from PAH.

Chemotherapy-Enriched THBS2-Deficient Cancer Stem Cells Drive Hepatocarcinogenesis through Matrix Softness Induced Histone H3 Modifications

The physical microenvironment is a critical mediator of tumor behavior. However, detailed biological and mechanistic insight is lacking. The present study reveals the role of chemotherapy-enriched CD133+ liver cancer stem cells (CSCs) with THBS2 deficiency. This subpopulation of cells contributes to a more aggressive cancer and functional stemness phenotype in hepatocellular carcinoma (HCC) by remodeling the extracellular matrix (ECM) through the regulation of matrix metalloproteinase (MMP) activity, collagen degradation, and matrix stiffness. The local soft spots created by these liver CSCs can enhance stemness and drug resistance and provide a route of escape to facilitate HCC metastasis. Interestingly, a positive feed-forward loop is identified where a local soft spot microenvironment in the HCC tumor is enriched with CD133 expressing cells that secrete markedly less ECM-modifying THBS2 upon histone H3 modification at its promoter region, allowing the maintenance of a localized soft spot matrix. Clinically, THBS2 deficiency is also correlated with low HCC survival, where high levels of CSCs with low THBS2 expression in HCC are associated with decreased collagen fiber deposits and an invasive tumor front. The findings have implications for the treatment of cancer stemness and for the prevention of tumor outgrowth through disseminated tumor cells.

Molecular and immunological developments in placentas

Cytotrophoblasts differentiate in two directions during early placentation: syncytiotrophoblasts (STBs) and extravillous trophoblasts (EVTs). STBs face maternal immune cells in placentas, and EVTs, which invade the decidua and uterine myometrium, face the cells in the uterus. This situation, in which trophoblasts come into contact with maternal immune cells, is known as the maternal-fetal interface. Despite fetuses and fetus-derived trophoblast cells being of the semi-allogeneic conceptus, fetuses and placentas are not rejected by the maternal immune system because of maternal-fetal tolerance. The acquired tolerance develops during normal placentation, resulting in normal fetal development in humans. In this review, we introduce placental development from the viewpoint of molecular biology. In addition, we discuss how the disruption of placental development could lead to complications in pregnancy, such as hypertensive disorder of pregnancy, fetal growth restriction, or miscarriage.

Rho-ROCK Signaling in Normal Physiology and as a Key Player in Shaping the Tumor Microenvironment

The Rho-ROCK signaling network has a range of specialized functions of key biological importance, including control of essential developmental processes such as morphogenesis and physiological processes including homeostasis, immunity, and wound healing. Deregulation of Rho-ROCK signaling actively contributes to multiple pathological conditions, and plays a major role in cancer development and progression. This dynamic network is critical in modulating the intricate communication between tumor cells, surrounding diverse stromal cells and the matrix, shaping the ever-changing microenvironment of aggressive tumors. In this chapter, we overview the complex regulation of the Rho-ROCK signaling axis, its role in health and disease, and analyze progress made with key approaches targeting the Rho-ROCK pathway for therapeutic benefit. Finally, we conclude by outlining likely future trends and key questions in the field of Rho-ROCK research, in particular surrounding Rho-ROCK signaling within the tumor microenvironment.

Epitranscriptomic profiling in human placenta: N6-methyladenosine modification at the 5'-untranslated region is related to fetal growth and preeclampsia

Intracellular mRNA levels are not always proportional to their respective protein levels, especially in the placenta. This discrepancy may be attributed to various factors including post‐transcriptional regulation, such as mRNA methylation (N6‐methyladenosine: m⁶A). Here, we conducted a comprehensive m⁶A analysis of human placental tissue from neonates with various birth weights to clarify the involvement of m⁶A in placental biology. The augmented m⁶A levels at the 5′‐untranslated region (UTR) in mRNAs of small‐for‐date placenta samples were dominant compared to reduction of m⁶A levels, whereas a decrease in m⁶A in the vicinity of stop codons was common in heavy‐for‐date placenta samples. Notably, most of these genes showed similar expression levels between the different birth weight categories. In particular, preeclampsia placenta samples showed consistently upregulated SMPD1 protein levels and increased m⁶A at 5′‐UTR but did not show increased mRNA levels. Mutagenesis of adenosines at 5′‐UTR of SMPD1 mRNAs actually decreased protein levels in luciferase assay. Collectively, our findings suggest that m⁶A both at the 5′‐UTR and in the vicinity of stop codon in placental mRNA may play important roles in fetal growth and disease.

Post-Passage rock inhibition induces cytoskeletal aberrations and apoptosis in Human embryonic stem cells

Human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs) are prone to anoikis after single cell dissociation. The small molecule, Y-27632 is known to increase survival of hESCs and hiPSCs by inhibiting the Rho-associated protein kinase (ROCK). However, the underlying mechanisms are still unclear. Here, we thoroughly screened small molecules to investigate the adhesion and survival of hESCs in adherent culture. Y-27632 provided higher adhesion and survival of hESCs by increased cell migration and preventing cell blebbing in single dissociated cells. The combination of Matrigel with poly-d-lysine increased the attachment and survival of dissociated cells via actin filament and microtubule spreading in Y-27632-treated cells. Although Y-27632 prevented apoptosis by suppressing actin filament contraction, microtubule bundling, and blebbing, prolonged Y-27632 treatment presented a different morphology in the attached growing hESC colony. It induced apoptosis of cells by promoting cytoplasmic spread, E-cadherin structural change, and increased detachment. It also induced actin cytoskeleton disruption, combined with microtubule and intermediate filament elongation. For optimal hPSC culture, our research suggests that Y-27632 should be removed shortly after passaging.

Endoplasmic reticulum stress disrupts lysosomal homeostasis and induces blockade of autophagic flux in human trophoblasts

Pregnancy is a stress factor culminating into mild endoplasmic reticulum (ER) stress, which is necessary for placental development. However, excessive or chronic ER stress in pre-eclamptic placentas leads to placental dysfunction. The precise mechanisms through which excessive ER stress impacts trophoblasts are not well understood. Here, we showed that ER stress reduces the number of lysosomes, resulting in inhibition of autophagic flux in trophoblast cells. ER stress also disrupted the translocation of lysosomes to the surface of trophoblast cells, and inhibited lysosomal exocytosis, whereby the secretion of lysosomal-associated membrane protein 1 (LAMP1) into culture media was significantly attenuated. In addition, we found that serum LAMP1 and beta-galactosidase levels were significantly decreased in pre-eclampsia patients compared to normal pregnant women, potentially indicating lysosomal dysfunction through ER stress in pre-eclamptic placentas. Thus, we demonstrated that excessive ER stress essentially disrupts homeostasis in trophoblasts in conjunction with autophagy inhibition by lysosomal impairment.

Current Understanding of Autophagy in Pregnancy

Autophagy is an evolutionarily conserved process in eukaryotes to maintain cellular homeostasis under environmental stress. Intracellular control is exerted to produce energy or maintain intracellular protein quality controls. Autophagy plays an important role in embryogenesis, implantation, and maintenance of pregnancy. This role includes supporting extravillous trophoblasts (EVTs) that invade the decidua (endometrium) until the first third of uterine myometrium and migrate along the lumina of spiral arterioles under hypoxic and low-nutrient conditions in early pregnancy. In addition, autophagy inhibition has been linked to poor placentation—a feature of preeclamptic placentas—in a placenta-specific autophagy knockout mouse model. Studies of autophagy in human placentas have revealed controversial results, especially with regard to preeclampsia and gestational diabetes mellitus (GDM). Without precise estimation of autophagy flux, wrong interpretation would lead to fixed tissues. This paper presents a review of the role of autophagy in pregnancy and elaborates on the interpretation of autophagy in human placental tissues.

HIF-2α, but not HIF-1α, mediates hypoxia-induced up-regulation of Flt-1 gene expression in placental trophoblasts

Placental hypoxia and elevated levels of circulating soluble Fms-like tyrosine kinase-1 (sFlt-1), an anti-angiogenic factor, are closely related to the pathogenesis of preeclampsia. Although sFlt-1 secretion from the placental trophoblasts is increased under hypoxic conditions, the underlying molecular mechanism remains unclear. Previously, an authentic hypoxia response element in the Flt-1 gene promoter was shown to be a potential binding site for hypoxia-inducible factors (HIFs). Here, we investigated the roles of HIF-1α and HIF-2α in Flt-1 gene expression in trophoblast-derived choriocarcinoma cell lines and cytotrophoblasts exposed to hypoxic conditions. In the cell lines, increased expression of sFlt-1 splice variants and nuclear accumulation of HIF-1α and HIF-2α were observed after hypoxic stimulation. A specific small interfering RNA or an inhibitor molecule targeting HIF-2α decreased hypoxia-induced up-regulation of Flt-1 gene expression. Moreover, in cytotrophoblasts, increased sFlt-1 mRNA expression and elevated sFlt-1 production were induced by hypoxic stimulation. Notably, hypoxia-induced elevation of sFlt-1 secretion from the cytotrophoblasts was inhibited by silencing the HIF-2α, but not HIF-1α mRNA. These findings suggest that hypoxia-induced activation of HIF-2α is essential for the increased production of sFlt-1 proteins in trophoblasts. Targeting the HIF-2α may be a novel strategy for the treatment of preeclampsia.

Transposable elements, placental development, and oocyte activation: Cellular stress and AMPK links jumping genes with the creation of human life

Transposable elements (TEs), also known as "jumping genes", are DNA sequences first described by Nobel laureate Barbara McClintock that comprise nearly half of the human genome and are able to transpose or move from one genomic location to another. As McClintock also noted that a genome "shock" or stress may induce TE activation and transposition, accumulating evidence suggests that cellular stress (e.g. mediated by increases in intracellular reactive oxygen species [ROS] and calcium [Ca2+], etc.) induces TE mobilization in several model organisms and L1s (a member of the retrotransposon class of TEs) are active and capable of retrotransposition in human oocytes, human sperm, and in human neural progenitor cells. Cellular stress also plays a critical role in human placental development, with cytotrophoblast (CTB) differentiation leading to the formation of the syncytiotrophoblast (STB), a cellular layer that facilitates nutrient and gas exchange between the mother and the fetus. Syncytin-1, a protein that promotes fusion of CTB cells and is necessary for STB formation, and its receptor is found in human sperm and human oocytes, respectively, and increases in ROS and Ca2+ promote trophoblast differentiation and syncytin-1 expression. Cellular stress is also essential in promoting human oocyte maturation and activation which, similar to TE mobilization, can be induced by compounds that increase intracellular Ca2+ and ROS levels. AMPK is a master metabolic regulator activated by increases in ROS, Ca2+, and/or an AMP(ADP)/ATP ratio increase, etc. as well as compounds that induce L1 mobilization in human cells. AMPK knockdown inhibits trophoblast differentiation and AMPK-activating compounds that promote L1 mobility also enhance trophoblast differentiation. Cellular stressors that induce TE mobilization (e.g. heat shock) also promote oocyte maturation in an AMPK-dependent manner and the antibiotic ionomycin activates AMPK, promotes TE activation, and induces human oocyte activation, producing normal, healthy children. Metformin promotes AMPK-dependent telomerase activation (critical for telomere maintenance) and induces activation of the endonuclease RAG1 (promotes DNA cleavage and transposition) via AMPK. Both RAG1 and telomerase are derived from TEs. It is our hypothesis that cellular stress and AMPK links TE activation and transposition with placental development and oocyte activation, facilitating both human genome evolution and the creation of all human life. We also propose the novel observation that various cellular stress-inducing compounds (e.g. metformin, resveratrol, etc.) may facilitate beneficial TE activation and transposition and enhance fertilization and embryological development through a common mechanism of AMPK activation.

RNA-Seq identifies genes whose proteins are transformative in the differentiation of cytotrophoblast to syncytiotrophoblast, in human primary villous and BeWo trophoblasts

The fusion of villous cytotrophoblasts into the multinucleated syncytiotrophoblast is critical for the essential functions of the mammalian placenta. Using RNA-Seq gene expression and quantitative protein expression, we identified genes and their cognate proteins which are coordinately up- or down-regulated in two cellular models of cytotrophoblast to syncytiotrophoblast development, human primary villous and human BeWo cytotrophoblasts. These include hCGβ, TREML2, PAM, CRIP2, INHA, FLRG, SERPINF1, C17orf96, KRT17 and SAA1. These findings provide avenues for further understanding the mechanisms underlying mammalian placental synctiotrophoblast development.

The crosstalk between breast carcinoma-associated fibroblasts and cancer cells promotes RhoA-dependent invasion via IGF-1 and PAI-1

Carcinoma-associated fibroblasts (CAFs) can remodel the extracellular matrix to promote cancer cell invasion, but the paracrine signaling between CAFs and cancer cells that regulates tumor cell migration remains to be identified. To determine how the interaction between CAFs and cancer cells modulates the invasiveness of cancer cells, we developed a 3-dimensional co-culture model composed of breast cancer (BC) MDA-MB-231 cell spheroids embedded in a collagen gel with and without CAFs. We found that the crosstalk between CAFs and cancer cells promotes invasion by stimulating the scattering of MDA-MB-231 cells, which was dependent on RhoA/ROCK/phospho MLC signaling in cancer cells but independent of RhoA in CAFs. The activation of RhoA/ROCK in cancer cells activates MLC and increases migration, while the genetic-down-regulation of RhoA and pharmacological inhibition of ROCK reduced cell scattering and invasion. Two distinct mechanisms induced the activation of the RhoA/ROCK pathway in MDA-MB-231 cells, the secretion of IGF-1 by CAFs and the upregulation of PAI-1 in cancer cells. In an orthotopic model of BC, IGF-1R inhibition decreased the incidence of lung metastasis, while Y27632-inhibition of ROCK enhanced the lung metastasis burden, which was associated with an increased recruitment of CAFs and expression of PAI-1. Thus the crosstalk between CAFs and BC cells increases the secretion of IGF-1 in CAFs and PAI-1 activity in cancer cells. Both IGF1 and PAI-1 activate RhoA/ROCK signaling in cancer cells, which increases cell scattering and invasion.

Glibenclamide inhibits NLRP3 inflammasome-mediated IL-1β secretion in human trophoblasts

Infection-associated pregnancy complications cause premature delivery. Caspase-1 is involved in the maturation of interleukin (IL)-1β, which is activated by the NLRP3 inflammasome. To characterize the significance of the NLRP3 inflammasome pathway in the placenta, the effects of activators and inhibitors on NLRP3-related molecules were examined using isolated primary trophoblasts. Caspase-1 and IL-1β mRNA expression was markedly increased in response to lipopolysaccharide (LPS), a toll-like receptor (TLR)4 ligand. Treatment with the potassium ionophore nigericin significantly increased the level of activated caspase-1. Treatment with either LPS or nigericin stimulated IL-1β secretion, whereas pretreatment with the ATP-sensitive K⁺ channel inhibitor glibenclamide, the Rho-associated coiled-coil kinase inhibitor Y-27632, or a caspase-1 inhibitor significantly decreased nigericin-induced IL-1β secretion. In addition, dibutyryl-cAMP, which induces trophoblast differentiation, decreased expression of NLRP3, caspase-1, and IL-1β. These findings suggest that trophoblasts can secrete IL-1β through the NLRP3/caspase-1 pathway, which is suppressed by glibenclamide, and that the TLR4-mediated NLRP3 inflammasome pathway is more likely to be stimulated in undifferentiated than differentiated trophoblasts. Our data support the hypothesis that inhibition of the NLRP3 inflammasome can suppress placental inflammation-associated disorders.