Objective: To provide clinical management guidelines for novel coronavirus in pregnancy. Methods:On February 5, 2020, a multidisciplinary teleconference comprising Chinese physicians and researchers was held and medical management strategies of COVID-19 infection in pregnancy were discussed. Results:Ten key recommendations were provided for the management of COVID-19 infections in pregnancy. Conclusion:Currently, there is no clear evidence regarding optimal delivery timing, the safety of vaginal delivery, or whether cesarean delivery prevents vertical transmission at the time of delivery; therefore, route of delivery and delivery timing should be individualized based on obstetrical indications and maternal-fetal status.

Summary In pregnancy, trophoblast invasion and uterine spiral artery remodeling are important for lowering maternal vascular resistance and increasing uteroplacental blood flow. Impaired spiral artery remodeling has long been implicated in preeclampsia, a major complication of pregnancy, but the underlying mechanisms remain unclear1, 2. Corin is a cardiac protease that activates atrial natriuretic peptide (ANP), a cardiac hormone important in regulating blood pressure3. Unexpectedly, corin expression was detected in the pregnant uterus4. Here we identify a novel function of corin and ANP in promoting trophoblast invasion and spiral artery remodeling. We show that pregnant corin- or ANP-deficient mice developed high blood pressure and proteinuria, characteristics of preeclampsia. In these mice, trophoblast invasion and uterine spiral artery remodeling were markedly impaired. Consistently, we find that ANP potently stimulated human trophoblasts in invading Matrigels. In patients with preeclampsia, uterine corin mRNA and protein levels were significantly lower than that in normal pregnancies. Moreover, we have identified corin gene mutations in preeclamptic patients, which decreased corin activity in processing pro-ANP. These results indicate that corin and ANP are essential for physiological changes at the maternal-fetal interface, suggesting that defects in corin and ANP function may contribute to preeclampsia.

The accuracy of NIPT for ChrX and ChrY can be improved substantially by integrating the results of maternal-plasma sequencing with those for maternal-WBC sequencing. The relatively high frequency of maternal mosaicism warrants mandatory WBC testing in both shotgun sequencing- and single-nucleotide polymorphism-based clinical NIPT after the finding of a potential fetal SCA.

In ovarian cancer, CD44+/CD117+ stem cells, also known as cancer‐initiating cells (CICs), are highly proliferative, have a low degree of differentiation, and are resistant to chemotherapeutics. Therefore, the CD44+/CD117+ subpopulation is thought to be an important target for novel therapeutic strategies. In this study, we investigated the role of microRNA‐199a (miR‐199a) in ovarian cancer stem cells. Luciferase reporter gene assays confirmed that miR‐199a targets CD44 via an miR‐199a‐binding site in the 3′‐UTR. CD44+/CD117+ ovarian CICs were enriched from human primary ovarian tumor tissues and confirmed by flow cytometric sorting. miR‐199a was cloned and transfected into ovarian CICs. CD44 mRNA and protein expression was significantly decreased in miR‐199a‐transfected ovarian CICs as compared with miR‐199a mutant‐transfected and untransfected cells. Cell cycle analysis, 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐tetrazolium bromide proliferation assays, the colony formation assay and the transwell migration assay indicated that miR‐199a significantly affected cell cycle regulation and suppressed the proliferation and invasive capacity of ovarian CICs in vitro. miR‐199a significantly increased the chemosensitivity of ovarian CICs to cisplatin, pacitaxel, and adriamycin, and reduced mRNA expression of the multidrug resistance gene ABCG2 as compared with miR‐199a mutant‐transfected and untransfected cells. The expression of stemness markers was also significantly reduced in miR‐199a‐transfected CICs as compared with miR‐199a mutant‐transfected and untransfected ovarian cells. Furthermore, xenograft experiments confirmed that miR‐199a suppressed the growth of xenograft tumors formed by ovarian CICs in vivo. Thus, expression of endogenous mature miR‐199a may prevent tumorigenesis in human ovarian cancer by regulating expression of its target gene CD44.

Multi-drug resistance is an important element which leads to ineffectiveness of chemotherapeutics. To identify subpopulations of cancerous prostate cells with multi-drug resistance and cancer stem-cell properties has recently become a major research interest. We identified a subpopulation from the prostate cancer cell line 22RV1, which have high surface expression of both CD117 and ABCG2. We found this subpopulation of cells termed CD117(+)/ABCG2(+) also overexpress stem cells markers such as Nanog, Oct4, Sox2, Nestin, and CD133. These cells are highly prolific and are also resistant to treatment with a variety of chemotherapeutics such as casplatin, paclitaxel, adriamycin, and methotrexate. In addition, CD117(+)/ABCG2(+) cells can readily establish tumors in vivo in a relatively short time. To investigate the mechanism of aggressive tumor growth and drug resistance, we examined the CpG islands on the ABCG2 promoter of CD117(+)/ABCG2(+) cells and found they were remarkably hypomethylated. Furthermore, chromatin immunoprecipitation assays revealed high levels of both histone 3 acetylation and H3K4 trimethylation at the CpG islands on the ABCG2 promoter. Our these data suggest that CD117(+)/ABCG2(+) cells could be reliably sorted from the human prostate cancer cell line 22RV1, and represent a valuable model for studying cancer cell physiology and multi-drug resistance. Furthermore, identification and study of these cells could have a profound impact on selection of individual treatment strategies, clinical outcome, and the design or selection of the next generation of chemotherapeutic agents.

One emerging model for the development of drugresistant tumors utilizes a pool of self-renewing malignant progenitors known as cancer stem cells (CSCs) or cancerinitiating cells (CICs). The purpose of this study was to propagate such CICs from the ovarian cancer cell line SKOV3. The SKOV3 sphere cells were selected using 40.0 mmol/l cisplatin and 10.0 mmol/l paclitaxel in serumfree culture system supplemented with epidermal growth factor, basic fibroblast growth factor, leukemia inhibitory factor, and insulin or standard serum-containing system. These cells formed non-adherent spheres under drug selection (cisplatin and paclitaxel) and serum-free culture system. The selected sphere cells are more resistant to cisplatin, paclitaxel, adriamycin, and methotrexate. Importantly, the sphere cells have the properties of selfrenewal, with high expression of the stem cell genes Nanog, Oct4, sox2, nestin, ABCG2, CD133, and the stem cell factor receptor CD117 (c-kit). Consistently, flow cytometric analysis revealed that the sphere cells have a much higher percentage of CD133 1 /CD1171 -positive cells (71%) than differentiated cells (33%). Moreover, the SKOV3 sphere cells are more tumorigenic. Furthermore, cDNA microarray and subsequent ontological analyses revealed that a large proportion of the classified genes were related to angiogenesis, extracellular matrix, integrin-mediated signaling pathway, cell adhesion, and cell proliferation. The subpopulation isolation from the SKOV3 cell line under this culture system offers a suitable in vitro model for studying ovarian CSCs in terms of their survival, self-renewal, and chemoresistance, and for developing therapeutic drugs that specifically interfere with ovarian CSCs.

Objectives: Stem cell transplantation has been reported to rescue ovarian function in a preclinical mouse model of chemotherapy-induced premature ovarian failure (POF); however, maintaining the survival and self-renewal of transplanted seed cells in ovarian tissues over the long-term remains a troublesome issue. In this study we aimed to determine whether the CD44+/CD105+ human amniotic fluid cell (HuAFCs) subpopulation represent potential seed cells for stem cell transplantation treatments in POF. Materials and methods: The CD44+/CD105+ subpopulation were isolated from HuAFCs, cultured in vitro, and injected into a cyclophosphamide-induced mouse model of POF. Results: Under continuous subculture in vitro, CD44+/CD105+ cells proliferated rapidly and expressed high levels of the proliferative markers Ki67 and survivin, as well as high levels of a number of mesenchymal stem cell biomarkers. Moreover, when red fluorescence protein (RFP)-transduced CD44+/CD105+ HuAFCs were transplanted into the ovaries of POF mice, the cells could be detected by fluorescence microscopy up to three weeks after injection. Furthermore, the BrdUrd incorporation assay and immunofluorescent staining demonstrated that CD44+/CD105+ HuAFCs underwent normal cycles of cell proliferation and self-renewal in the ovarian tissues of POF mice over the long-term. Conclusions: The mesenchymal stem cell properties and long-term in vivo survival of CD44+/CD105+ HuAFCs make them ideal seed cells for stem cell transplantation to treat POF.

Although many techniques can be used to generate multitype-induced pluripotent stem (iPS) cells from multitype seed cells, improving the efficiency and shortening the period of cell reprogramming remain troublesome issues. In this study, to generate iPS cells, CD34⁺ cells, isolated from human amniotic fluid cells (HuAFCs) by flow cytometry, were infected with retroviruses carrying only one reprogramming factor (Oct4) and cultured on human amniotic epithelial cell (HuAEC) feeder layers. Approximately 4 to 5 days after viral infection, some embryonic stem cell (ESC)-like colonies appeared among the feeder cells. These colonies were positive for alkaline phosphatase and expressed high levels of ESC pluripotent markers (Nanog, Sox2, Oct4, CD133, and Rex1). Moreover, these iPS cells exhibited high levels of telomerase activity and had normal karyotypes. Additionally, these cells could differentiate into cell types from all 3 germ layers in vivo and in teratomas. In summary, we report a novel way of iPS generation that uses CD34⁺ HuAFCs as seed cells. Using this method, we can generate human iPS cells with greater efficiency and safety (the oncogenic factors, c-Myc and Klf4, were not used), and using the minimum number of reprogramming factors (only one factor, Oct4). Besides, HuAECs were used as feeder layers to culture human iPS cells, which could not only avoid contamination with heterogeneous proteins, but also maintain iPS cells in a self-renewing and undifferentiated state for a long time.