MyMedR

Displaying all 10 publications

Abstract:

Sort:

Impact of Three-Dimentional Culture Systems on Hepatic Differentiation of Puripotent Stem Cells and Beyond

Ramasamy TS, Ong ALC, Cui W

Adv Exp Med Biol, 2018 10 26;1077:41-66.
PMID: 30357683 DOI: 10.1007/978-981-13-0947-2_4

Generation of functional hepatocytes from human pluripotent stem cells (hPSCs) is a vital tool to produce large amounts of human hepatocytes, which hold a great promise for biomedical and regenerative medicine applications. Despite a tremendous progress in developing the differentiation protocols recapitulating the developmental signalling and stages, these resulting hepatocytes from hPSCs yet achieve maturation and functionality comparable to those primary hepatocytes. The absence of 3D milieu in the culture and differentiation of these hepatocytes may account for this, at least partly, thus developing an optimal 3D culture could be a step forward to achieve this aim. Hence, review focuses on current development of 3D culture systems for hepatic differentiation and maturation and the future perspectives of its application.
Construction of a doxycycline inducible lentivirus that expresses stem cell-specific miR-302 cluster

Tan GC, Wong YP, Cui W, Dibb N

Malays J Pathol, 2020 Apr;42(1):91-97.
PMID: 32342936

INTRODUCTION: The polycistronic miR-302 cluster encodes five miRNA genes that have an important role in the regulation of embryonic stem cell function. Studies showed that the miR-302 cluster can reprogram both mouse and human fibroblasts to induced pluripotent stem cells (iPSCs) with high efficiency. The aim of this study was to generate an inducible lentivirus that expresses miR-302 cluster in order to further investigate somatic cell reprogramming by these miRNAs.
MATERIALS AND METHODS: The miR-302 cluster was amplified by polymerase chain reaction technique from human genomic DNA and was ligated into pTRIPz, an inducible lentiviral vector.
RESULTS: MRC5 fibroblasts and HEK293 (human embryonic kidney) cells were infected with pTRIPz-302 cluster lentivirus and the family of 302 miRNAs were strongly expressed in HEK293 cells but lowly expressed in MRC5 fibroblasts. When cultured in hESC conditions, MRC5 cells expressed only low levels of DNMT3B, Nanog, Oct4 and Lin28 and failed to show stem cell induction. The red fluorescent expression seen in the majority of MRC5 cells, indicated that the rate of infection by lentivirus was efficient.
DISCUSSION: The efficiency of reprogramming may be improved perhaps by either using a different cell type or a high expression vector with a different type of promoter.
Fulltext Investigating tourism experiences and attention allocation of outbound tourists through the lens of the two-factor theory: A grounded theory analysis of Chinese tourists' travelogues in Malaysia

Li X, Cui W, Chee WM

Heliyon, 2023 Jul;9(7):e17896.
PMID: 37483812 DOI: 10.1016/j.heliyon.2023.e17896

A top-notch travel experience is vital for boosting a destination's competitiveness. Outbound travel notes of online travel agency capture tourists' experiences and emotions during their journeys, providing valuable insights for understanding tourist consumption behavior and improving tourism service policies. This study analyzes 1,012 travel blogs of Chinese tourists visiting Malaysia using grounded theory methodology. A dual-factor theoretical model is developed through open coding, spindle coding, and selective coding, illustrating the attention allocation problem of outbound tourists in their travel experiences. The study's hygiene factors comprise basic features, management aspects, and transportation components, while motivational factors include cultural elements, resource considerations, emotional factors, media influences, and commercial aspects. Research findings indicate that outbound tourists prioritize motivational factors, such as interpersonal service attributes and inherent emotional components. These factors play a crucial role in stimulating travel motivation and crafting memorable experiences. Moreover, hygiene factors, like infrastructure and security conditions, also impact tourists' experiences and are crucial for reducing dissatisfaction among outbound travelers. These results provide fresh perspectives on the factors influencing outbound tourists' experiences and their focal points during trips. The findings have significant implications for public sectors and industry professionals in tourism. By addressing the motivating and hygiene factors important to outbound tourists, they can enhance and fine-tune tourism service policies, ultimately increasing destination competitiveness. Measures such as improving infrastructure, raising service quality, and amplifying cultural experiences at the destination can all contribute to better travel experiences for tourists.
Evaluating the resource curse hypothesis and the interplay of financial development, human development, and political stability in seven emerging economies

Cui W, Yang Y, Dai J

Environ Sci Pollut Res Int, 2023 Oct;30(50):109559-109570.
PMID: 37775636 DOI: 10.1007/s11356-023-29907-6

The present study empirically confabulates the authenticity of the "resource curse hypothesis" in selected emerging nations. Furthermore, we also assessed the interconnections of three essential economic indicators with financial development, i.e., human development, political stability, and gross domestic product. To effectuate these objectives, we used annual data for the time frame 1990 to 2020 and advanced panel estimation techniques for getting the empirical outcomes. The study's empirical outcomes illustrate the existence of the "resource curse hypothesis" in sample nations. In addition, human development index and gross domestic product play an essential part in the furtherance of financial development in the long-run. The human development index is upsurging the financial development. Furthermore, political stability is also exerting a favorable influence on financial development. A similar interconnection is observed in the short-time period; nonetheless, the amplitude of the short-run impacts is smaller if we have a look at the long-run impacts. The empirical analysis offers a few pertinent policy insights for policymakers to improve the situation in the selected sample. Note: Financial development positively interconnected with human development, GDP and political stability while negatively associated with natural resources, respectively.
Fulltext The Intra- and Extra-Telomeric Role of TRF2 in the DNA Damage Response

Imran SAM, Yazid MD, Cui W, Lokanathan Y

Int J Mol Sci, 2021 Sep 14;22(18).
PMID: 34576063 DOI: 10.3390/ijms22189900

Telomere repeat binding factor 2 (TRF2) has a well-known function at the telomeres, which acts to protect the telomere end from being recognized as a DNA break or from unwanted recombination. This protection mechanism prevents DNA instability from mutation and subsequent severe diseases caused by the changes in DNA, such as cancer. Since TRF2 actively inhibits the DNA damage response factors from recognizing the telomere end as a DNA break, many more studies have also shown its interactions outside of the telomeres. However, very little has been discovered on the mechanisms involved in these interactions. This review aims to discuss the known function of TRF2 and its interaction with the DNA damage response (DDR) factors at both telomeric and non-telomeric regions. In this review, we will summarize recent progress and findings on the interactions between TRF2 and DDR factors at telomeres and outside of telomeres.
The significant sex-biased expression pattern of Sp-Wnt4 provides novel insights into the ovarian development of mud crab (Scylla Paramamosain)

Farhadi A, Fang S, Zhang Y, Cui W, Fang H, Ikhwanuddin M, et al.

Int J Biol Macromol, 2021 Jul 31;183:490-501.
PMID: 33957197 DOI: 10.1016/j.ijbiomac.2021.04.186

The wingless-type MMTV integration site family member-4 (Wnt4), a member of the wingless-related integration site (Wnt) family, is widely accepted as a key regulator of ovarian development in mammals. In this study, a full-length cDNA of Wnt4 (designated as Sp-Wnt4) was cloned, characterized, and functionally studied in mud crab (Scylla paramamosain). The full-length cDNA of Sp-Wnt4 consists of 2659 bp with an open reading frame (ORF) encoding 359 amino acids, a 907 bp 5'-UTR and a 672 bp 3'-UTR. Sp-Wnt4 contains 25 cysteine (Cys) residues and three potential N-glycosylation sites. Sp-Wnt4 protein shared the highest identity (98.9%) to the Wnt4 protein of Portunus trituberculatus. The phylogenetic tree showed that Sp-Wnt4 and Wnt4 protein of Malacostracan crustaceans clustered together, indicating that they had a close genetic distance. Sp-Wnt4 was expressed at a higher level in the ovary compared to other tissues, with the highest expression level at the third stage (O-III) of the ovarian development (P < 0.05). A downward trend was observed in the expression level of Sp-Wnt4 from the embryo stage to crablet stages (P < 0.05). After unilateral eyestalk ablation, the expression level of Sp-Wnt4 significantly increased in testis (14-fold) and downregulated (3.1-fold) in the gill (P < 0.05) of females. In situ hybridization (ISH) assay revealed that Sp-Wnt4 transcripts were mainly localized in the cytoplasm of oocyte cells. These findings showed that Sp-Wnt4 play crucial roles in the ovarian development of S. paramamosain. In conclusion, our study provides novel insights into the evolution and roles of the Wnt4 gene.
Fulltext Evidence of Sex Differentiation Based on Morphological Traits During the Early Development Stage of Mud Crab Scylla paramamosain

Cui W, Fang S, Lv L, Huang Z, Lin F, Wu Q, et al.

Front Vet Sci, 2021;8:712942.
PMID: 34395579 DOI: 10.3389/fvets.2021.712942

In order to uncover the sexual difference in morphology and how early they appear during the development stage of mud crab Scylla paramamosain, we measured, observed, and biostatistically analyzed morphological traits related to sex. For unveiling the morphological differences between sexes, morphological traits involving abdomen width (AW), carapace length (CL), and carapace width (CW) were first measured during the crablet development stage of S. paramamosain in the present study. The correlation analyses and path analyses exhibited that sexual dimorphism in the third abdomen width (AW3) and fourth abdomen width (AW4) could be used for sex identification from stage C VI (stage VI of crablet). Based on the stepwise discriminant analysis and standardized traits, a sex discriminant equation was constructed, which is capable for sex identification in crablets from stage C VI. Observations for secondary sexual traits and abdomen morphology (shape and pleopods) using a dissecting microscope or scanning electron microscope indicated that sexes are easily identified at stage C VIII according to the abdomen shape; meanwhile, at stage C II based on pleopod difference, and at stage C I by the presence or absence of gonopores. The findings in this study contribute greatly to the accuracy of sex identification of S. paramamosain during the early development stage, which promotes the understanding of the morphological differentiation mechanism of sex.
High-resolution chromosome-level genome of Scylla paramamosain provides molecular insights into adaptive evolution in crabs

Zhang Y, Yuan Y, Zhang M, Yu X, Qiu B, Wu F, et al.

BMC Biol, 2024 Nov 07;22(1):255.
PMID: 39511558 DOI: 10.1186/s12915-024-02054-1

BACKGROUND: Evolutionary adaptation drives organismal adjustments to environmental pressures, exemplified in the diverse morphological and ecological adaptations seen in Decapoda crustaceans, particularly brachyuran crabs. Crabs thrive in diverse ecosystems, from coral reefs to hydrothermal vents and terrestrial habitats. Despite their ecological importance, the genetic mechanisms underpinning their developmental processes, reproductive strategies, and nutrient acquisition remain poorly understood.
RESULTS: Here, we report a comprehensive genomic analysis of the green mud crab Scylla paramamosain using ultralong sequencing technologies, achieving a high-quality chromosome-level assembly. The refined 1.21 Gb genome, with an impressive contig N50 of 11.45 Mb, offers a valuable genomic resource. The genome exhibits 33,662 protein-coding genes, enriched in various pathways related to development and environmental adaptation. Gene family analysis shows expansion in development-related pathways and contraction in metabolic pathways, indicating niche adaptations. Notably, investigation into Hox gene regulation sheds light on their role in pleopod development, with the Abd-A gene identified as a linchpin. Post-transcriptional regulation involving novel-miR1317 negatively regulates Abd-A levels. Furthermore, the potential role of fru gene in ovarian development and the identification of novel-miR35 as a regulator of Spfru2 add complexity to gene regulatory networks. Comparative functional analysis across Decapoda species reveals neo-functionalization of the elovl6 gene in the synthesis of long-chain polyunsaturated fatty acids (LC-PUFA), suggesting its importance in environmental adaptation.
CONCLUSIONS: Our findings shed light on various aspects of crab biology, including genome sequencing, assembly, and annotation, as well as gene family expansion, contraction, and regulatory mechanisms governing crucial developmental processes such as metamorphosis, reproductive strategies, and fatty acid metabolism.
Fulltext 5' isomiR variation is of functional and evolutionary importance

Tan GC, Chan E, Molnar A, Sarkar R, Alexieva D, Isa IM, et al.

Nucleic Acids Res, 2014 Aug;42(14):9424-35.
PMID: 25056318 DOI: 10.1093/nar/gku656

We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3' and/or 5' end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5' differences and in support of this we report that a 5' isomiR-9-1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5' isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes.
Fulltext Immunity and clinical efficacy of an inactivated enterovirus 71 vaccine in healthy Chinese children: a report of further observations

Liu L, Mo Z, Liang Z, Zhang Y, Li R, Ong KC, et al.

BMC Med, 2015;13:226.
PMID: 26381232 DOI: 10.1186/s12916-015-0448-7

To investigate the long-term effects on immunity of an inactivated enterovirus 71 (EV71) vaccine and its protective efficacy.