Yanhong Yu

Modeling of hemophilia A using patient-specific induced pluripotent stem cells derived from urine cells

AIMSnHemophilia A (HA) is a severe, congenital bleeding disorder caused by the deficiency of clotting factor VIII (FVIII). For years, traditional laboratory animals have been used to study HA and its therapies, although animal models may not entirely mirror the human pathophysiology. Human induced pluripotent stem cells (iPSCs) can undergo unlimited self-renewal and differentiate into all cell types. This study aims to generate hemophilia A (HA) patient-specific iPSCs that differentiate into disease-affected hepatocyte cells. These hepatocytes are potentially useful for in vitro disease modeling and provide an applicable cell source for autologous cell therapy after genetic correction.nnnMAIN METHODSnIn this study, we mainly generated iPSCs from urine collected from HA patients with integration-free episomal vectors PEP4-EO2S-ET2K containing human genes OCT4, SOX2, SV40LT and KLF4, and differentiated these iPSCs into hepatocyte-like cells. We further identified the genetic phenotype of the FVIII genes and the FVIII activity in the patient-specific iPSC derived hepatic cells.nnnKEY FINDINGSnHA patient-specific iPSCs (HA-iPSCs) exhibited typical pluripotent properties evident by immunostaining, in vitro assays and in vivo assays. Importantly, we showed that HA-iPSCs could differentiate into functional hepatocyte-like cells and the HA-iPSC-derived hepatocytes failed to produce FVIII, but otherwise functioned normally, recapitulating the phenotype of HA disease in vitro.nnnSIGNIFICANCEnHA-iPSCs, particular those generated from the urine using a non-viral approach, provide an efficient way for modeling HA in vitro. Furthermore, HA-iPSCs and their derivatives serve as an invaluable cell source that can be used for gene and cell therapy in regenerative medicine.

Chronic hepatitis C virus infection is associated with increased risk of preterm birth: a meta-analysis of observational studies.

Although several epidemiological studies reported that maternal chronic hepatitis C virus (HCV) infection had significantly increased risk of undergoing adverse obstetrical and perinatal outcomes, studies on the relationship between HCV infection and risk of preterm birth (PTB) have yielded inconclusive and inconsistent results. Therefore, we conducted a meta‐analysis to investigate the association between HCV infection and PTB. The electronic database was searched until 1 September 2014. Relevant studies reporting the association between HCV infection and the risk of PTB were included for further evaluation. Statistical analysis was performed using revmen 5.3 and stata 10.0. Nine studies involving 4186698 participants and 5218 HCV infection cases were included. A significant association between HCV infection and PTB was observed (odds ratio = 1.62, 95% CI 1.48–1.76, P < 0.001, fixed‐effects model). Stratification according to maternal smoking/alcohol abuse, maternal drug abuse or coinfected with HBV and/or HIV matched groups still demonstrated that women with HCV infection had a high risk for PTB. Findings from our meta‐analysis suggested that maternal HCV infection was significantly associated with an increased risk of PTB. In the future, pathophysiological studies are warranted to ascertain the causality and explore the possible biological mechanisms involved.

Advanced glycation end products as an upstream molecule triggers ROS-induced sFlt-1 production in extravillous trophoblasts: A novel bridge between oxidative stress and preeclampsia

Although abnormal soluble fms-like tyrosine kinase-1 (sFlt-1) production is thought to be an important factor in the pathogenesis of pre-eclampsia, the mechanisms that regulate the production of sFlt-1 during pre-eclampsia are unclear. Accumulation of advanced glycation end products (AGEs) is prevalent in obesity, advanced maternal age, diabetes mellitus, and polycystic ovary syndrome. Alterations in the regulation and signaling of angiogenic pathways have been considered as a link between these conditions and pre-eclampsia. The purpose of this study was to explore the possible effects of AGEs on sFlt-1 secretion in extravillous trophoblasts (EVT). A EVT cell line (HRT-8/SVneo) was treated with various concentrations of AGEs-BSA. The mRNA expression of sFlt-1, vascular endothelial growth factor (VEGF), and placental growth factor (PlGF) in EVT were detected with real-time polymerase chain reaction. The secretion of sFlt-1, VEGF, and PlGF protein from EVT was measured with ELISA. The levels of intracellular reactive oxygen species (ROS) production were determined by DCFH-DA. Exposure of EVT to AGEs-BSA induced increased intracellular ROS generation and overexpression of sFlt-1 at mRNA and protein levels in a dose dependent manner. Anti-RAGE immunoglobulin G or apocynin (an inhibitors of NADPH oxidase) could decrease the intracellular ROS generation and subsequently suppressed the production of sFlt-1 at mRNA and protein levels. Our data suggested that AGEs may be a new class of important mediator in the regulation of angiogenic pathways of EVT. Accumulation of AGEs might contribute to the pathogenesis of preeclampsia by promoting sFlt-1 production through activation of RAGE/NADPH oxidase dependent pathway in EVT.

RETRACTED: The developmental pattern of the RAS/RAF/Erk1/2 pathway in the BTBR autism mouse model

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).

Advanced oxidation protein products enhances soluble Fms-like tyrosine kinase 1 expression in trophoblasts: A possible link between oxidative stress and preeclampsia

Accumulation of advanced oxidation protein products (AOPPs) is prevalent in obesity, advanced maternal age, diabetes mellitus, and polycystic ovary syndrome. Alterations in the regulation and signaling of angiogenic pathways have been recognized as a link between these conditions and pre-eclampsia. To investigate the possible impact of AOPPs on soluble Fms-like tyrosine kinase 1 (sFlt-1) expression in trophoblasts. A trophoblast cell line (HRT-8/SVneo) was treated with various concentrations of AOPPs. The mRNA expression of sFlt-1, vascular endothelial growth factor (VEGF), and placental growth factor (PlGF) in trophoblasts were measured with the use of real-time polymerase chain reaction; and the secretion of sFlt-1, VEGF, and PlGF protein from trophoblasts were detected with the use of ELISA. Exposure of HRT-8/SVneo cells to AOPPs induced overexpression of sFlt-1 at mRNA and protein levels in a dose dependent manner. These effects could be inhibited by apocynin, an inhibitors of NADPH oxidase. Our data identified AOPPs as a class of important mediator in the regulation and signaling of angiogenic pathways of trophoblasts. Accumulation of AOPPs might contributes to the pathogenesis of preeclampsia by promoting sFlt-1 production in trophoblasts.

The risk of placental abruption and placenta previa in pregnant women with chronic hepatitis B viral infection: A systematic review and meta-analysis

INTRODUCTIONnSeveral epidemiological studies have found a positive association between chronic hepatitis B virus (CHB) infection and the risk of placental abruption and placenta previa, but various studies have reported conflicting findings. The objective was to systematically review the literature to determine a possible association between CHB infection and these two placental complications.nnnMETHODSnWe conducted a computerized search in electronic database through March 1, 2014, supplemented with a manual search of reference lists, to identify original published research on placental abruption and placenta previa rates in women with CHB infection. Data were independently extracted, and relative risks were calculated. The meta-analysis was performed using Stata version 10.0 software.nnnRESULTSnFive studies involving 9088 placenta previa cases were identified. No significant association between CHB infection and placenta previa was identified (OR = 0.98, 95% CI = 0.60-1.62). Five studies involving 15571 placental abruption cases were identified. No significant association between CHB infection and placental abruption was identified (OR = 1.42, 95% CI, 0.93-2.15).nnnDISCUSSIONnThe immune response against the virus represents a key factor in determining infection outcomes. No observation of significant increased risk of the placental complications could be partially explained by the complex immune response during CHB infection.nnnCONCLUSIONSnOur meta-analysis found no evidence of significant associations between CHB infection and increased risk of placental abruption as well as placenta previa. Further well-designed studies were warranted to assess any potential association between CHB infection and increased risk of placental abruption as well as placenta previa.

The effects of PBDE-209 exposure during pregnancy on placental ET-1 and eNOS expression and the birth weight of offspring.

Decabrominated diphenyl ether (PBDE‐209) is a persistent organic pollutant. Gestational exposure to PBDE‐209 can accumulate in pregnant women and fetuses via the placenta and umbilical cord, affecting perinatal outcome. In this study, pregnant Sprague–Dawley (SD) rats were randomly divided into five groups and intragastrically administered peanut oil (vehicle) 1, 5 and 10 mg/kg by body weight (b.w.) of PBDE‐209, or nothing (control) from day 0 (G0) to day 21 (G21) gestation, respectively. Placental samples were collected on G21 by cesarean section. The mRNA and protein expressions of ET‐1, eNOS and iNOS in the placenta were examined using qRT‐PCR and Western blot, respectively. Total nitric oxide (NO) in the placenta was measured using a specific ELISA kit. Compared with the control and vehicle groups, the mRNA expression of ET‐1 and iNOS in the placenta was gradually and significantly increased after exposure to increasing concentrations of PBDE‐209 (P < 0.05), while the mRNA level of eNOS in the placenta was gradually and significantly reduced after exposure to increasing concentrations of PBDE‐209 (P < 0.05). The expression trends of ET‐1, eNOS and iNOS proteins were consistent with those of mRNA expression. Interestingly, the production of total NO was significantly increased after exposure to 5 and 10 mg/kg b.w. PBDE‐209 (P < 0.05). Finally, the birth weight of the offspring rats was significantly reduced after maternal exposure to 5 and 10 mg/kg b.w. PBDE‐209 compared with the control and vehicle groups (P < 0.05). These results suggest that PBDE‐209 exposure during pregnancy upregulates ET‐1 and iNOS expression, but decreases eNOS expression in the placenta, as well as reduces the birth weight of offspring.

Decreased expression of fibroblast growth factor 13 in early-onset preeclampsia is associated with the increased trophoblast permeability

OBJECTIVEnIntracellular protein fibroblast growth factor 13 (FGF13) is highly expressed in human placenta, although its biological function remains unexplored. The aims of this study were to investigate the expression of FGF13 in placentae with early-onset preeclampsia (PE) and the associated mechanisms in the pathophysiology of PE.nnnMETHODSnThe expression levels of FGF13 in placentae obtained from patients with early-onset PE and normal pregnancies were assessed using immunofluorescent staining, Western blot assays and quantitative PCR. We knocked down FGF13 in trophoblast cell lines BeWo and HTR8/SVneo, and analyzed cell permeability. Clinical trophoblast cell-cell junctions were identified by cytokeratin 7 (CK7) immunofluorescent staining of human placental sections. The expressions of FGF13 were manipulated in BeWo and HTR8/SVneo cell lines, and the expressions of E-cadherin were quantified by reverse transcription followed by quantitative PCR, Western blot assays and immunofluorescent staining. The expressions of FGF13 and E-cadherin were further confirmed in the isolated human primary trophoblasts.nnnRESULTSnDownregulation of FGF13 along with trophoblast disarrangement were found in human placentae with early-onset PE. In trophoblast cell lines decreased FGF13 expression resulted in increased cell permeability and decreased E-cadherin expression. The FGF13 insufficiency-mediated loss of E-cadherin was further confirmed in the human villous trophoblasts isolated from PE patients.nnnCONCLUSIONnFGF13 was downregulated in human placentae with early-onset PE. FGF13 played an important role in maintaining placental trophoblast permeability via the modulation of E-cadherin.

Generation of trophoblast-like cells from the amnion in vitro: A novel cellular model for trophoblast development

Despite the high incidence of trophoblast-related diseases, the molecular mechanism of inadequate early trophoblast development is still unclear due to the lack of an appropriate cellular model inxa0vitro. In the present study, we reprogrammed the amniotic cells to be induced pluripotent stem cells (iPSCs) via a non-virus and non-integrated method and subsequently differentiated them into trophoblast-like cells by a modified BMP4 strategy in E6 medium. Compared with the previously studied trophoblast-like cells from ESCs, the iPSCs derived trophoblast-like cells behave similarly in terms of gene expression profiles and biofunctions. Also we confirmed the differentiating tendency from iPSCs to be syncytiotrophoblasts-like cells might be caused by inappropriate differentiating oxygen condition. Additionally, we preliminarily indicated inxa0vitro artificial differentiation of iPSCs also undergoing a possible trophoblastic stem cell stage, as witnessed inxa0vivo. In conclusion, we provided an inxa0vitro cellular model to study early trophoblast development for specific individual, by using the feasible amnion.

Retraction notice to “The developmental pattern of the RAS/RAF/Erk1/2 pathway in the BTBR autism mouse model” [Int. J. Dev. Neurosci. 39 (2014) 2–8]

Retraction notice Retraction notice to “The developmental pattern of the RAS/RAF/Erk1/2 pathway in the BTBR autism mouse model” [Int. J. Dev. Neurosci. 39 (2014) 2–8] Ailan Yin , Yuwen Qiu , Beijia , Tianrong Song , Yanhong Yu, Ian Alberts , Mei Zhong a,∗ a Department of Obstetrics & Gynecology, Nanfang Hospital, Guangzhou, China b Southern Medical University, Guangzhou, China c Department of Natural Sciences, LarGuardia CC, CUNY, NY, NY 11101, USA