The plant hormone abscisic acid stimulates megakaryocyte differentiation from human iPSCs in vitro

Abstract In flowering plants, repression of the seed maturation program is essential for the transition from the seed to the vegetative phase, but the underlying mechanisms remain poorly understood. The B3-domain protein VIVIPAROUS1/ABSCISIC ACID-INSENSITIVE3-LIKE 1 (VAL1) is involved in repressing the seed maturation program. Here we uncovered a molecular network triggered by the plant hormone brassinosteroid (BR) that inhibits the seed maturation program during the seed-to-seedling transition in Arabidopsis (Arabidopsis thaliana). val1-2 mutant seedlings treated with a BR biosynthesis inhibitor form embryonic structures, whereas BR signaling gain-of-function mutations rescue the embryonic structure trait. Furthermore, the BR-activated transcription factors BRI1-EMS-SUPPRESSOR 1 and BRASSINAZOLE-RESISTANT 1 bind directly to the promoter of AGAMOUS-LIKE15 (AGL15), which encodes a transcription factor involved in activating the seed maturation program, and suppress its expression. Genetic analysis indicated that BR signaling is epistatic to AGL15 and represses the seed maturation program by downregulating AGL15. Finally, we showed that the BR-mediated pathway functions synergistically with the VAL1/2-mediated pathway to ensure the full repression of the seed maturation program. Together, our work uncovered a mechanism underlying the suppression of the seed maturation program, shedding light on how BR promotes seedling growth.

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The CAD risk locus 9p21 increases the risk of vascular calcification in an iPSC-derived VSMC model

Stem Cell Research & Therapy ◽

10.1186/s13287-021-02229-5 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Anja Trillhaase ◽

Beatrice Schmidt ◽

Marlon Märtens ◽

Undine Haferkamp ◽

Jeanette Erdmann ◽

...

Keyword(s):

Coronary Artery ◽

Vascular Calcification ◽

Alizarin Red ◽

Vitro Assay ◽

Human Ipscs ◽

Increased Risk ◽

Risk Locus ◽

9P21 Locus ◽

Cad Risk

Abstract Background Coronary artery disease (CAD) is the leading cause of death worldwide. Chromosome locus 9p21 was the first to be associated with increased risk of CAD and coronary artery calcification (CAC). Vascular calcification increases the risk for CAD. Vascular smooth muscle cells (VSMCs) are one of the major cell types involved in the development of vascular calcification. Methods So far, mainly animal models or primary SMCs have been used to model human vascular calcification. In this study, a human in vitro assay using iPSC-derived VSMCs was developed to examine vascular calcification. Human iPSCs were derived from a healthy non-risk (NR) and risk (R) donor carrying SNPs in the 9p21 locus. Additionally, 9p21 locus knockouts of each donor iPSC line (NR and R) were used. Following differentiation, the iPSC-derived VSMCs were characterized based on cell type, proliferation, and migration rate, along with calcium phosphate (CaP) deposits. CaP deposits were confirmed using Calcein and Alizarin Red S staining and then quantified. Results The data demonstrated significantly more proliferation, migration, and CaP deposition in VSMCs derived from the R and both KO iPSC lines than in those derived from the NR line. Molecular analyses confirmed upregulation of calcification markers. These results are consistent with recent data demonstrating increased calcification when the 9p21 murine ortholog is knocked-out. Conclusion Therefore, in conclusion, genetic variation or deletion of the CAD risk locus leads to an increased risk of vascular calcification. This in vitro human iPSC model of calcification could be used to develop new drug screening strategies to combat CAC.

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Utilising Induced Pluripotent Stem Cells in Neurodegenerative Disease Research: Focus on Glia

International Journal of Molecular Sciences ◽

10.3390/ijms22094334 ◽

2021 ◽

Vol 22 (9) ◽

pp. 4334

Author(s):

Katrina Albert ◽

Jonna Niskanen ◽

Sara Kälvälä ◽

Šárka Lehtonen

Keyword(s):

Stem Cells ◽

Neurodegenerative Diseases ◽

Neurodegenerative Disease ◽

Induced Pluripotent Stem Cells ◽

Glial Cells ◽

Pluripotent Stem Cells ◽

Cell Types ◽

Human Ipscs ◽

Induced Pluripotent

Induced pluripotent stem cells (iPSCs) are a self-renewable pool of cells derived from an organism’s somatic cells. These can then be programmed to other cell types, including neurons. Use of iPSCs in research has been two-fold as they have been used for human disease modelling as well as for the possibility to generate new therapies. Particularly in complex human diseases, such as neurodegenerative diseases, iPSCs can give advantages over traditional animal models in that they more accurately represent the human genome. Additionally, patient-derived cells can be modified using gene editing technology and further transplanted to the brain. Glial cells have recently become important avenues of research in the field of neurodegenerative diseases, for example, in Alzheimer’s disease and Parkinson’s disease. This review focuses on using glial cells (astrocytes, microglia, and oligodendrocytes) derived from human iPSCs in order to give a better understanding of how these cells contribute to neurodegenerative disease pathology. Using glia iPSCs in in vitro cell culture, cerebral organoids, and intracranial transplantation may give us future insight into both more accurate models and disease-modifying therapies.

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Human iPSC-Based Modeling of Central Nerve System Disorders for Drug Discovery

International Journal of Molecular Sciences ◽

10.3390/ijms22031203 ◽

2021 ◽

Vol 22 (3) ◽

pp. 1203

Author(s):

Lu Qian ◽

Julia TCW

Keyword(s):

Drug Discovery ◽

Disease Modeling ◽

Three Dimensional ◽

Structural Complexity ◽

Induced Pluripotent Stem Cell ◽

Cell Types ◽

Central Nerve System ◽

Human Ipscs ◽

Nerve System

A high-throughput drug screen identifies potentially promising therapeutics for clinical trials. However, limitations that persist in current disease modeling with limited physiological relevancy of human patients skew drug responses, hamper translation of clinical efficacy, and contribute to high clinical attritions. The emergence of induced pluripotent stem cell (iPSC) technology revolutionizes the paradigm of drug discovery. In particular, iPSC-based three-dimensional (3D) tissue engineering that appears as a promising vehicle of in vitro disease modeling provides more sophisticated tissue architectures and micro-environmental cues than a traditional two-dimensional (2D) culture. Here we discuss 3D based organoids/spheroids that construct the advanced modeling with evolved structural complexity, which propels drug discovery by exhibiting more human specific and diverse pathologies that are not perceived in 2D or animal models. We will then focus on various central nerve system (CNS) disease modeling using human iPSCs, leading to uncovering disease pathogenesis that guides the development of therapeutic strategies. Finally, we will address new opportunities of iPSC-assisted drug discovery with multi-disciplinary approaches from bioengineering to Omics technology. Despite technological challenges, iPSC-derived cytoarchitectures through interactions of diverse cell types mimic patients’ CNS and serve as a platform for therapeutic development and personalized precision medicine.

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A Screen for Genes That Function in Abscisic Acid Signaling in Arabidopsis thaliana

Genetics ◽

10.1093/genetics/161.3.1247 ◽

2002 ◽

Vol 161 (3) ◽

pp. 1247-1255 ◽

Cited By ~ 1

Author(s):

Eiji Nambara ◽

Masaharu Suzuki ◽

Suzanne Abrams ◽

Donald R McCarty ◽

Yuji Kamiya ◽

...

Keyword(s):

Abscisic Acid ◽

Growth And Development ◽

Plant Hormone ◽

The Other ◽

Aba Signaling ◽

Wild Type ◽

Plant Growth And Development ◽

Diverse Range ◽

Abscisic Acid Signaling ◽

Aba Insensitive

Abstract The plant hormone abscisic acid (ABA) controls many aspects of plant growth and development under a diverse range of environmental conditions. To identify genes functioning in ABA signaling, we have carried out a screen for mutants that takes advantage of the ability of wild-type Arabidopsis seeds to respond to (−)-(R)-ABA, an enantiomer of the natural (+)-(S)-ABA. The premise of the screen was to identify mutations that preferentially alter their germination response in the presence of one stereoisomer vs. the other. Twenty-six mutants were identified and genetic analysis on 23 lines defines two new loci, designated CHOTTO1 and CHOTTO2, and a collection of new mutant alleles of the ABA-insensitive genes, ABI3, ABI4, and ABI5. The abi5 alleles are less sensitive to (+)-ABA than to (−)-ABA. In contrast, the abi3 alleles exhibit a variety of differences in response to the ABA isomers. Genetic and molecular analysis of these alleles suggests that the ABI3 transcription factor may perceive multiple ABA signals.

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Arabidopsis NPF4.6 and NPF5.1 Control Leaf Stomatal Aperture by Regulating Abscisic Acid Transport

Genes ◽

10.3390/genes12060885 ◽

2021 ◽

Vol 12 (6) ◽

pp. 885

Author(s):

Takafumi Shimizu ◽

Yuri Kanno ◽

Hiromi Suzuki ◽

Shunsuke Watanabe ◽

Mitsunori Seo

Keyword(s):

Abscisic Acid ◽

Plant Hormone ◽

Leaf Surface ◽

Stomatal Closure ◽

Guard Cells ◽

Cell Types ◽

Acid Transport ◽

Wild Type ◽

Vascular Tissues ◽

Abscisic Acid Transport

The plant hormone abscisic acid (ABA) is actively synthesized in vascular tissues and transported to guard cells to promote stomatal closure. Although several transmembrane ABA transporters have been identified, how the movement of ABA within plants is regulated is not fully understood. In this study, we determined that Arabidopsis NPF4.6, previously identified as an ABA transporter expressed in vascular tissues, is also present in guard cells and positively regulates stomatal closure in leaves. We also found that mutants defective in NPF5.1 had a higher leaf surface temperature compared to the wild type. Additionally, NPF5.1 mediated cellular ABA uptake when expressed in a heterologous yeast system. Promoter activities of NPF5.1 were detected in several leaf cell types. Taken together, these observations indicate that NPF5.1 negatively regulates stomatal closure by regulating the amount of ABA that can be transported from vascular tissues to guard cells.

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