Search for: embryonic-stem-cell
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    Enhanced Waddington landscape model with cell-cell communication can explain molecular mechanisms of self-organization

    , Article Bioinformatics ; Volume 35, Issue 20 , 2019 , Pages 4081-4088 ; 13674803 (ISSN) Fooladi, H ; Moradi, P ; Sharifi Zarchi, A ; Hosein Khalaj, B ; Berger, B ; Sharif University of Technology
    Oxford University Press  2019
    The molecular mechanisms of self-organization that orchestrate embryonic cells to create astonishing patterns have been among major questions of developmental biology. It is recently shown that embryonic stem cells (ESCs), when cultured in particular micropatterns, can self-organize and mimic the early steps of pre-implantation embryogenesis. A systems-biology model to address this observation from a dynamical systems perspective is essential and can enhance understanding of the phenomenon. Results: Here, we propose a multicellular mathematical model for pattern formation during in vitro gastrulation of human ESCs. This model enhances the basic principles of Waddington epigenetic landscape... 

    The metabolic network model of primed/naive human embryonic stem cells underlines the importance of oxidation-reduction potential and tryptophan metabolism in primed pluripotency

    , Article Cell and Bioscience ; Volume 9, Issue 1 , 2019 ; 20453701 (ISSN) Yousefi, M ; Marashi, S. A ; Sharifi Zarchi, A ; Taleahmad, S ; Sharif University of Technology
    BioMed Central Ltd  2019
    Background: Pluripotency is proposed to exist in two different stages: Naive and Primed. Conventional human pluripotent cells are essentially in the primed stage. In recent years, several protocols have claimed to generate naive human embryonic stem cells (hESCs). To the best of our knowledge, none of these protocols is currently recognized as the gold standard method. Furthermore, the consistency of the resulting cells from these diverse protocols at the molecular level is yet to be shown. Additionally, little is known about the principles that govern the metabolic differences between naive and primed pluripotency. In this work, using a computational approach, we tried to shed light on... 

    MicroRNA profiling reveals important functions of miR-125b and let-7a during human retinal pigment epithelial cell differentiation

    , Article Experimental Eye Research ; Volume 190 , 2020 Shahriari, F ; Satarian, L ; Moradi, S ; Sharifi Zarchi, A ; Günther, S ; Kamal, A ; Totonchi, M ; Mowla, S. J ; Braun, T ; Baharvand, H ; Sharif University of Technology
    Academic Press  2020
    Retinal pigment epithelial (RPE) cells are indispensable for eye organogenesis and vision. To realize the therapeutic potential of in vitro-generated RPE cells for cell-replacement therapy of RPE-related retinopathies, molecular mechanisms of RPE specification and maturation need to be investigated. So far, many attempts have been made to decipher the regulatory networks involved in the differentiation of human pluripotent stem cells into RPE cells. Here, we exploited a highly-efficient RPE differentiation protocol to determine global expression patterns of microRNAs (miRNAs) during human embryonic stem cell (hESC) differentiation into RPE using small RNA sequencing. Our results revealed a... 

    DNA and RNA extractions from eukaryotic and prokaryotic cells by graphene nanoplatelets

    , Article RSC Advances ; Vol. 4, issue. 105 , 2014 , p. 60720-60728 Hashemi, E ; Akhavan, O ; Shamsara, M ; Valimehr, S ; Rahighi, R ; Sharif University of Technology
    Graphene nanoplatelets with lateral dimensions of ∼50-200 nm and thicknesses <2 nm were utilized for the extraction of nucleic acids (NAs) from eukaryotic and prokaryotic cells. The graphene nanoplatelets (both chemically exfoliated graphene oxide nanoplatelets and hydrazine-reduced graphene oxide nanoplatelets) successfully extracted plasmid DNA (pDNA) from Escherichia coli bacteria, comparable to a conventional phenol-chloroform (PC) method. Furthermore, it was found that the yield of graphene nanoplatelets in genomic DNA (gDNA) and RNA extractions from embryonic stem cells (ESCs) was also comparable to the yield of the conventional methods. The effects of the graphene nanoplatelets on... 

    Embryonic stem cells maintain an undifferentiated state on dendrimer-immobilized surface with D-glucose display

    , Article Polymers ; Volume 3, Issue 4 , 2011 , Pages 2078-2087 ; 20734360 (ISSN) Mashayekhan, S ; Kim, M. H ; Kino Oka, M ; Miyazaki, J. I ; Taya, M ; Sharif University of Technology
    In serial passaging cultures of mouse embryonic stem (ES) cells, we employed a dendrimer-immobilized substrate that displayed D-glucose as a terminal ligand. The D-glucose-displaying dendrimer (GLU/D) surface caused the ES cells to form loosely attached spherical colonies, while those on a gelatin-coated surface formed flatter colonies that were firmly attached to the surface. Despite the morphological similarities between the colonies on the GLU/D surface and aggregates on a conventional bacteriological dish, immunostaining and RT-PCR analyses revealed the maintenance of cells within the spherical colonies on the GLU/D surface in an undifferentiated state with very low expressions of... 

    Microfluidic systems for stem cell-based neural tissue engineering

    , Article Lab on a Chip - Miniaturisation for Chemistry and Biology ; Volume 16, Issue 14 , 2016 , Pages 2551-2571 ; 14730197 (ISSN) Karimi, M ; Bahrami, S ; Mirshekari, H ; Moosavi Basri, S. M ; Bakhshian Nik, A ; Aref, A. R ; Akbari, M ; Hamblin, M. R ; Sharif University of Technology
    Royal Society of Chemistry  2016
    Neural tissue engineering aims at developing novel approaches for the treatment of diseases of the nervous system, by providing a permissive environment for the growth and differentiation of neural cells. Three-dimensional (3D) cell culture systems provide a closer biomimetic environment, and promote better cell differentiation and improved cell function, than could be achieved by conventional two-dimensional (2D) culture systems. With the recent advances in the discovery and introduction of different types of stem cells for tissue engineering, microfluidic platforms have provided an improved microenvironment for the 3D-culture of stem cells. Microfluidic systems can provide more precise... 

    DNA methylation regulates discrimination of enhancers from promoters through a H3K4me1-H3K4me3 seesaw mechanism

    , Article BMC Genomics ; 2017 , Volume 18, Issue 1 ; 14712164 (ISSN) Sharifi Zarchi, A ; Gerovska, D ; Adachi, K ; Totonchi, M ; Pezeshk, H ; Taft, R. J ; Schöler, H. R ; Chitsaz, H ; Sadeghi, M ; Baharvand, H ; Araúzo Bravo, M. J ; Sharif University of Technology
    Background: DNA methylation at promoters is largely correlated with inhibition of gene expression. However, the role of DNA methylation at enhancers is not fully understood, although a crosstalk with chromatin marks is expected. Actually, there exist contradictory reports about positive and negative correlations between DNA methylation and H3K4me1, a chromatin hallmark of enhancers. Results: We investigated the relationship between DNA methylation and active chromatin marks through genome-wide correlations, and found anti-correlation between H3K4me1 and H3K4me3 enrichment at low and intermediate DNA methylation loci. We hypothesized "seesaw" dynamics between H3K4me1 and H3K4me3 in the low... 

    Smart liposomal drug delivery for treatment of oxidative stress model in human embryonic stem cell-derived retinal pigment epithelial cells

    , Article International Journal of Pharmaceutics ; Volume 548, Issue 1 , 2018 , Pages 62-72 ; 03785173 (ISSN) Behroozi, F ; Abdkhodaie, M. J ; Sadeghi Abandansari, H ; Satarian, L ; Kazemi Ashtiani, M ; Jaafari, M. R ; Baharvand, H ; Sharif University of Technology
    Oxidative stress has been implicated in the progression of age-related macular degeneration (AMD). Treatment with antioxidants seems to delay progression of AMD. In this study, we suggested an antioxidant delivery system based on redox-sensitive liposome composed of phospholipids and a diselenide centered alkyl chain. Dynamic light scattering assessment indicated that the liposomes had an average size of 140 nm with a polydispersity index below 0.2. The percentage of encapsulation efficiency of the liposomes was calculated by high-performance liquid chromatography. The carriers were loaded with N-acetyl cysteine as a model antioxidant drug. We demonstrated responsiveness of the nanocarrier... 

    Controlling differentiation of stem cells for developing personalized organ-on-chip platforms

    , Article Advanced Healthcare Materials ; Volume 7, Issue 2 , 2018 ; 21922640 (ISSN) Geraili, A ; Jafari, P ; Sheikh Hassani, M ; Heidary Araghi, B ; Mohammadi, M. H ; Ghafari, A. M ; Hassanpour Tamrin, S ; Pezeshgi Modarres, H ; Rezaei Kolahchi, A ; Ahadian, S ; Sanati Nezhad, A ; Sharif University of Technology
    Wiley-VCH Verlag  2018
    Organ-on-chip (OOC) platforms have attracted attentions of pharmaceutical companies as powerful tools for screening of existing drugs and development of new drug candidates. OOCs have primarily used human cell lines or primary cells to develop biomimetic tissue models. However, the ability of human stem cells in unlimited self-renewal and differentiation into multiple lineages has made them attractive for OOCs. The microfluidic technology has enabled precise control of stem cell differentiation using soluble factors, biophysical cues, and electromagnetic signals. This study discusses different tissue- and organ-on-chip platforms (i.e., skin, brain, blood–brain barrier, bone marrow, heart,... 

    Small RNA sequencing reveals dlk1-dio3 locus-embedded microRNAs as major drivers of ground-state pluripotency

    , Article Stem Cell Reports ; Volume 9, Issue 6 , 2017 , Pages 2081-2096 ; 22136711 (ISSN) Moradi, S ; Sharifi Zarchi, A ; Ahmadi, A ; Mollamohammadi, S ; Stubenvoll, A ; Günther, S ; Hosseini Salekdeh, G ; Asgari, S ; Braun, T ; Baharvand, H ; Sharif University of Technology
    Ground-state pluripotency is a cell state in which pluripotency is established and maintained through efficient repression of endogenous differentiation pathways. Self-renewal and pluripotency of embryonic stem cells (ESCs) are influenced by ESC-associated microRNAs (miRNAs). Here, we provide a comprehensive assessment of the “miRNome” of ESCs cultured under conditions favoring ground-state pluripotency. We found that ground-state ESCs express a distinct set of miRNAs compared with ESCs grown in serum. Interestingly, most “ground-state miRNAs” are encoded by an imprinted region on chromosome 12 within the Dlk1-Dio3 locus. Functional analysis revealed that ground-state miRNAs embedded in the...