scholarly journals Engineering Cell Fate: The Roles of iPSC Transcription Factors, Chemicals, Barriers and Enhancing Factors in Reprogramming and Transdifferentiation

2015 ◽  
Author(s):  
Behnam Ebrahimi

Direct reprogramming technology has emerged as an outstanding technique for the generation of induced pluripotent stem (iPS) cells and various specialized cells directly from somatic cells of different species. Recent studies dissecting the molecular mechanisms of reprogramming have methodologically improved the quality, ease and efficiency of reprogramming and eliminated the need for genome modifications with integrating viral vectors. With these advancements, direct reprogramming technology has moved closer to clinical application. Here, we provide a comprehensive overview of the cutting-edge findings regarding distinct barriers of reprogramming to pluripotency, strategies to enhance reprogramming efficiency, and chemical reprogramming as one of the non-integrating approaches in iPS cell generation. In addition to direct transdifferentiation, pluripotency factor-induced transdifferentiation or cell activation and signaling directed (CASD) lineage conversion is described as a robust strategy for the generation of both tissue-specific progenitors and clinically relevant cell types. Then, we consider the possibility that a combined method of inhibition of roadblocks (e.g. p53, p21, p57, Mbd3, etc.), and application of enhancing factors in a chemical reprogramming paradigm would be a safe, reliable and effective approach in pluripotent reprogramming and transdifferentiation. Furthermore, with respect to the state of native, aberrant, and target gene regulatory networks in reprogrammed cell populations, CellNet is reviewed as a computational platform capable of evaluating the fidelity of reprogramming methods and refining current engineering strategies. Ultimately, we conclude that a faithful, highly efficient and integration-free reprogramming paradigm would provide powerful tools for research studies, drug-based induced regeneration, cell transplantation therapies and other regenerative medicine purposes.

Author(s):  
Boxun Li ◽  
Gary C. Hon

As we near a complete catalog of mammalian cell types, the capability to engineer specific cell types on demand would transform biomedical research and regenerative medicine. However, the current pace of discovering new cell types far outstrips our ability to engineer them. One attractive strategy for cellular engineering is direct reprogramming, where induction of specific transcription factor (TF) cocktails orchestrates cell state transitions. Here, we review the foundational studies of TF-mediated reprogramming in the context of a general framework for cell fate engineering, which consists of: discovering new reprogramming cocktails, assessing engineered cells, and revealing molecular mechanisms. Traditional bulk reprogramming methods established a strong foundation for TF-mediated reprogramming, but were limited by their small scale and difficulty resolving cellular heterogeneity. Recently, single-cell technologies have overcome these challenges to rapidly accelerate progress in cell fate engineering. In the next decade, we anticipate that these tools will enable unprecedented control of cell state.


2019 ◽  
Vol 35 (1) ◽  
pp. 433-452 ◽  
Author(s):  
Begüm Aydin ◽  
Esteban O. Mazzoni

Cellular reprogramming experiments from somatic cell types have demonstrated the plasticity of terminally differentiated cell states. Recent efforts in understanding the mechanisms of cellular reprogramming have begun to elucidate the differentiation trajectories along the reprogramming processes. In this review, we focus mainly on direct reprogramming strategies by transcription factors and highlight the variables that contribute to cell fate conversion outcomes. We review key studies that shed light on the cellular and molecular mechanisms by investigating differentiation trajectories and alternative cell states as well as transcription factor regulatory activities during cell fate reprogramming. Finally, we highlight a few concepts that we believe require attention, particularly when measuring the success of cell reprogramming experiments.


2015 ◽  
Vol 212 (13) ◽  
pp. 2289-2304 ◽  
Author(s):  
Binh L. Phong ◽  
Lyndsay Avery ◽  
Tina L. Sumpter ◽  
Jacob V. Gorman ◽  
Simon C. Watkins ◽  
...  

T cell (or transmembrane) immunoglobulin and mucin domain protein 3 (Tim-3) has attracted significant attention as a novel immune checkpoint receptor (ICR) on chronically stimulated, often dysfunctional, T cells. Antibodies to Tim-3 can enhance antiviral and antitumor immune responses. Tim-3 is also constitutively expressed by mast cells, NK cells and specific subsets of macrophages and dendritic cells. There is ample evidence for a positive role for Tim-3 in these latter cell types, which is at odds with the model of Tim-3 as an inhibitory molecule on T cells. At this point, little is known about the molecular mechanisms by which Tim-3 regulates the function of T cells or other cell types. We have focused on defining the effects of Tim-3 ligation on mast cell activation, as these cells constitutively express Tim-3 and are activated through an ITAM-containing receptor for IgE (FcεRI), using signaling pathways analogous to those in T cells. Using a variety of gain- and loss-of-function approaches, we find that Tim-3 acts at a receptor-proximal point to enhance Lyn kinase-dependent signaling pathways that modulate both immediate-phase degranulation and late-phase cytokine production downstream of FcεRI ligation.


Cells ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 255 ◽  
Author(s):  
Miruna Mihaela Micheu ◽  
Alina Ioana Scarlatescu ◽  
Alexandru Scafa-Udriste ◽  
Maria Dorobantu

Despite significant progress in treating ischemic cardiac disease and succeeding heart failure, there is still an unmet need to develop effective therapeutic strategies given the persistent high-mortality rate. Advances in stem cell biology hold great promise for regenerative medicine, particularly for cardiac regeneration. Various cell types have been used both in preclinical and clinical studies to repair the injured heart, either directly or indirectly. Transplanted cells may act in an autocrine and/or paracrine manner to improve the myocyte survival and migration of remote and/or resident stem cells to the site of injury. Still, the molecular mechanisms regulating cardiac protection and repair are poorly understood. Stem cell fate is directed by multifaceted interactions between genetic, epigenetic, transcriptional, and post-transcriptional mechanisms. Decoding stem cells’ “panomic” data would provide a comprehensive picture of the underlying mechanisms, resulting in patient-tailored therapy. This review offers a critical analysis of omics data in relation to stem cell survival and differentiation. Additionally, the emerging role of stem cell-derived exosomes as “cell-free” therapy is debated. Last but not least, we discuss the challenges to retrieve and analyze the huge amount of publicly available omics data.


2021 ◽  
Author(s):  
Zhibin Li ◽  
chengcheng Sun ◽  
Fei Wang ◽  
Xiran Wang ◽  
Jiacheng Zhu ◽  
...  

Background: Immune cells play important roles in mediating immune response and host defense against invading pathogens. However, insights into the molecular mechanisms governing circulating immune cell diversity among multiple species are limited. Methods: In this study, we compared the single-cell transcriptomes of 77 957 immune cells from 12 species using single-cell RNA-sequencing (scRNA-seq). Distinct molecular profiles were characterized for different immune cell types, including T cells, B cells, natural killer cells, monocytes, and dendritic cells. Results: The results revealed the heterogeneity and compositions of circulating immune cells among 12 different species. Additionally, we explored the conserved and divergent cellular cross-talks and genetic regulatory networks among vertebrate immune cells. Notably, the ligand and receptor pair VIM-CD44 was highly conserved among the immune cells. Conclusions: This study is the first to provide a comprehensive analysis of the cross-species single-cell atlas for peripheral blood mononuclear cells (PBMCs). This research should advance our understanding of the cellular taxonomy and fundamental functions of PBMCs, with important implications in evolutionary biology, developmental biology, and immune system disorders


Author(s):  
Vikram Sabapathy ◽  
Gabrielle Costlow ◽  
Rajkumar Venkatadri ◽  
Murat Dogan ◽  
Sanjay Kumar ◽  
...  

: The advent of organoids has renewed researcher's interest in in vitro cell culture systems. A wide variety of protocols, primarily utilizing pluripotent stem cells, are under development to improve organoid generation to mimic organ development. The complexity of organoids generated is greatly influenced based on the method used. Understanding the process of kidney organoid formation gives developmental insights into how renal cells form, mature, and interact with the adjacent cells to form specific spatiotemporal structural patterns. This knowledge can bridge the gaps in understanding in vivo renal developmental processes. Evaluating genetic and epigenetic signatures in specialized cell types can help interpret the molecular mechanisms governing cell fate. In addition, development in single-cell RNA sequencing and 3D bioprinting and microfluidic technologies has led to better identification and understanding of a variety of cell types during differentiation and designing of complex structures to mimic the conditions in vivo. While several reviews have highlighted the application of kidney organoids, there is no comprehensive review of various methodologies specifically focusing on the kidney organoids. This review summarizes the updated differentiation methodologies, applications, and challenges associated with kidney organoids. Here we have comprehensively collated all the different variables influencing the organoid generation.


F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 1477
Author(s):  
Guangdun Peng ◽  
Jing-Dong J. Han

Embryonic development and stem cell differentiation, during which coordinated cell fate specification takes place in a spatial and temporal context, serve as a paradigm for studying the orderly assembly of gene regulatory networks (GRNs) and the fundamental mechanism of GRNs in driving lineage determination. However, knowledge of reliable GRN annotation for dynamic development regulation, particularly for unveiling the complex temporal and spatial architecture of tissue stem cells, remains inadequate. With the advent of single-cell RNA sequencing technology, elucidating GRNs in development and stem cell processes poses both new challenges and unprecedented opportunities. This review takes a snapshot of some of this work and its implication in the regulative nature of early mammalian development and specification of the distinct cell types during embryogenesis.


2015 ◽  
Vol 35 (16) ◽  
pp. 2716-2728 ◽  
Author(s):  
Lluis Morey ◽  
Alexandra Santanach ◽  
Luciano Di Croce

Embryonic stem cells (ESCs) are characterized by their ability to self-renew and to differentiate into all cell types of a given organism. Understanding the molecular mechanisms that govern the ESC state is of great interest not only for basic research—for instance, ESCs represent a perfect system to study cellular differentiationin vitro—but also for their potential implications in human health, as these mechanisms are likewise involved in cancer progression and could be exploited in regenerative medicine. In this minireview, we focus on the latest insights into the molecular mechanisms mediated by the pluripotency factors as well as their roles during differentiation. We also discuss recent advances in understanding the function of the epigenetic regulators, Polycomb and MLL complexes, in ESC biology.


Science ◽  
2019 ◽  
Vol 366 (6461) ◽  
pp. 116-120 ◽  
Author(s):  
Nathan D. Lord ◽  
Thomas M. Norman ◽  
Ruoshi Yuan ◽  
Somenath Bakshi ◽  
Richard Losick ◽  
...  

Cell fate decision circuits must be variable enough for genetically identical cells to adopt a multitude of fates, yet ensure that these states are distinct, stably maintained, and coordinated with neighboring cells. A long-standing view is that this is achieved by regulatory networks involving self-stabilizing feedback loops that convert small differences into long-lived cell types. We combined regulatory mutants and in vivo reconstitution with theory for stochastic processes to show that the marquee features of a cell fate switch in Bacillus subtilis—discrete states, multigenerational inheritance, and timing of commitments—can instead be explained by simple stochastic competition between two constitutively produced proteins that form an inactive complex. Such antagonistic interactions are commonplace in cells and could provide powerful mechanisms for cell fate determination more broadly.


2019 ◽  
Author(s):  
Yosuke Tanigawa ◽  
Ethan S. Dyer ◽  
Gill Bejerano

AbstractWe present WhichTF, a novel computational method to identify dominant transcription factors (TFs) from chromatin accessibility measurements. To rank TFs, WhichTF integrates high-confidence genome-wide computational prediction of TF binding sites based on evolutionary sequence conservation, putative gene-regulatory models, and ontology-based gene annotations. Applying WhichTF, we find that the identified dominant TFs have been implicated as functionally important in well-studied cell types, such as NF-κB family members in lymphocytes and GATA factors in cardiac tissue. To distinguish the transcriptional regulatory landscape in closely related samples, we devise a differential analysis framework and demonstrate its utility in lymphocyte, mesoderm developmental, and disease cells. We also find TFs known for stress response in multiple samples, suggesting routine experimental caveats that warrant careful consideration. WhichTF yields biological insight into known and novel molecular mechanisms of TF-mediated transcriptional regulation in diverse contexts, including human and mouse cell types, cell fate trajectories, and disease-associated tissues.


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