scholarly journals Model systems for regeneration:Arabidopsis

Development ◽  
2021 ◽  
Vol 148 (6) ◽  
Author(s):  
Mabel Maria Mathew ◽  
Kalika Prasad
Keyword(s):  
Arabidopsis Thaliana ◽  
Plant Regeneration ◽  
Cell Walls ◽  
Molecular Mechanisms ◽  
Molecular Genetic ◽  
Cell Types ◽  
Model Systems ◽  
Specific Cell ◽  
Multi Scale ◽  
Perfect Model

ABSTRACTPlants encompass unparalleled multi-scale regenerative potential. Despite lacking specialized cells that are recruited to injured sites, and despite their cells being encased in rigid cell walls, plants exhibit a variety of regenerative responses ranging from the regeneration of specific cell types, tissues and organs, to the rebuilding of an entire organism. Over the years, extensive studies on embryo, shoot and root development in the model plant species Arabidopsis thaliana have provided insights into the mechanisms underlying plant regeneration. These studies highlight how Arabidopsis, with its wide array of refined molecular, genetic and cell biological tools, provides a perfect model to interrogate the cellular and molecular mechanisms of reprogramming during regeneration.

scholarly journals Stomatal Development in the Context of Epidermal Tissues

2021 ◽  
Author(s):  
Keiko U Torii
Keyword(s):  
Arabidopsis Thaliana ◽  
Molecular Genetic ◽  
Cell Lineage ◽  
Optimal Growth ◽  
Cell Types ◽  
State Transitions ◽  
Stomatal Development ◽  
Water Control ◽  
Pavement Cells ◽  
The Core

Abstract Background Stomata are adjustable pores on the surface of plant shoots for efficient gas exchange and water control. The presence of stomata is essential for plant growth and survival, and the evolution of stomata is considered as a key developmental innovation of the land plants, allowing colonization on land from aquatic environments some 450 million years ago. In the past two decades, molecular genetic studies using the model plant Arabidopsis thaliana identified key genes and signalling modules that regulate stomatal development: master-regulatory transcription factors that orchestrate cell-state transitions and peptide-receptor signal transduction pathways, which, together, enforce proper patterning of stomata within the epidermis. Studies in diverse plant species, ranging from bryophytes to angiosperm grasses, have begun to unravel the conservation and uniqueness of the core modules in stomatal development. Scope Here, I review the mechanisms of stomatal development in the context of epidermal tissue patterning. First, I introduce the core regulatory mechanisms of stomatal patterning and differentiation in the model species Arabidopsis thaliana. Subsequently, experimental evidence is presented supporting the idea that different cell types within the leaf epidermis, namely stomata, hydathodes pores, pavement cells, and trichomes, either share developmental origins or mutually influence each other’s gene regulatory circuits during development. Emphasis is taken on extrinsic and intrinsic signals regulating the balance between stomata and pavement cells, specifically by controlling the fate of Stomatal-Lineage Ground Cells (SLGCs) to remain within the stomatal-cell lineage or differentiate into pavement cells. Finally, I discuss the influence of inter-tissue-layer communication between the epidermis and underlying mesophyll/vascular tissues on stomatal differentiation. Understanding the dynamic behaviors of stomatal precursor cells and their differentiation in the broader context of tissue and organ development may help design plants tailored for optimal growth and productivity in specific agricultural applications and a changing environment.

scholarly journals Shisa6 mediates cell-type specific regulation of depression in the nucleus accumbens

2021 ◽  
Author(s):  
Hee-Dae Kim ◽  
Jing Wei ◽  
Tanessa Call ◽  
Nicole Teru Quintus ◽  
Alexander J. Summers ◽  
...  
Keyword(s):  
Nucleus Accumbens ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Current Treatment ◽  
Specific Cell ◽  
Excitatory Synapses ◽  
Cell Type ◽  
Cell Type Specific ◽  
Specific Regulation ◽  
Circuit Function

AbstractDepression is the leading cause of disability and produces enormous health and economic burdens. Current treatment approaches for depression are largely ineffective and leave more than 50% of patients symptomatic, mainly because of non-selective and broad action of antidepressants. Thus, there is an urgent need to design and develop novel therapeutics to treat depression. Given the heterogeneity and complexity of the brain, identification of molecular mechanisms within specific cell-types responsible for producing depression-like behaviors will advance development of therapies. In the reward circuitry, the nucleus accumbens (NAc) is a key brain region of depression pathophysiology, possibly based on differential activity of D1- or D2- medium spiny neurons (MSNs). Here we report a circuit- and cell-type specific molecular target for depression, Shisa6, recently defined as an AMPAR component, which is increased only in D1-MSNs in the NAc of susceptible mice. Using the Ribotag approach, we dissected the transcriptional profile of D1- and D2-MSNs by RNA sequencing following a mouse model of depression, chronic social defeat stress (CSDS). Bioinformatic analyses identified cell-type specific genes that may contribute to the pathogenesis of depression, including Shisa6. We found selective optogenetic activation of the ventral tegmental area (VTA) to NAc circuit increases Shisa6 expression in D1-MSNs. Shisa6 is specifically located in excitatory synapses of D1-MSNs and increases excitability of neurons, which promotes anxiety- and depression-like behaviors in mice. Cell-type and circuit-specific action of Shisa6, which directly modulates excitatory synapses that convey aversive information, identifies the protein as a potential rapid-antidepressant target for aberrant circuit function in depression.

scholarly journals Transforming Growth Factor β-Mediated Transcriptional Repression of c-myc Is Dependent on Direct Binding of Smad3 to a Novel Repressive Smad Binding Element

2004 ◽  
Vol 24 (6) ◽  
pp. 2546-2559 ◽  
Author(s):  
Joshua P. Frederick ◽  
Nicole T. Liberati ◽  
David S. Waddell ◽  
Yigong Shi ◽  
Xiao-Fan Wang
Keyword(s):  
Growth Factor ◽  
Transcriptional Repression ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Cell Types ◽  
Specific Cell ◽  
Smad Proteins ◽  
Smad Binding Element

ABSTRACT Smad proteins are the most well-characterized intracellular effectors of the transforming growth factor β (TGF-β) signal. The ability of the Smads to act as transcriptional activators via TGF-β-induced recruitment to Smad binding elements (SBE) within the promoters of TGF-β target genes has been firmly established. However, the elucidation of the molecular mechanisms involved in TGF-β-mediated transcriptional repression are only recently being uncovered. The proto-oncogene c-myc is repressed by TGF-β, and this repression is required for the manifestation of the TGF-β cytostatic program in specific cell types. We have shown that Smad3 is required for both TGF-β-induced repression of c-myc and subsequent growth arrest in keratinocytes. The transcriptional repression of c-myc is dependent on direct Smad3 binding to a novel Smad binding site, termed a repressive Smad binding element (RSBE), within the TGF-β inhibitory element (TIE) of the c-myc promoter. The c-myc TIE is a composite element, comprised of an overlapping RSBE and a consensus E2F site, that is capable of binding at least Smad3, Smad4, E2F-4, and p107. The RSBE is distinct from the previously defined SBE and may partially dictate, in conjunction with the promoter context of the overlapping E2F site, whether the Smad3-containing complex actively represses, as opposed to transactivates, the c-myc promoter.

Investigation of the Stem Cells Used in Modeling Human Placental Trophoblast

2021 ◽  
Author(s):  
Lulu Ji ◽  
Lin Wang
Keyword(s):  
Stem Cells ◽  
Molecular Mechanisms ◽  
Embryonic Stem ◽  
Cell Lineage ◽  
Cell Types ◽  
Model Systems ◽  
Alternative Methods ◽  
Laboratory Animals ◽  
Placental Development ◽  
Induced Pluripotent

Human placenta is vital for fetal development, and act as an interface between the fetus and the expecting mother. Abnormal placentati on underpins various pregnancy complications such as miscarriage, pre-eclampsia and intrauterine growth restriction. Despite the important role of placenta, the molecular mechanisms governing placental formation and trophoblast cell lineage specification is poorly understand. It is mostly due to the lack of appropriate model system. The great various in placental types across mammals make it limit for the use of laboratory animals in studying human placental development. However, over the past few years, alternative methods have been employed, including human embryonic stem cells, induced pluripotent stem cells, human trophoblast stem cell, and 3-dimensional organoids. Herein, we summarize the present knowledge about human development, differentiated cell types in the trophoblast epithelium and current human placental trophoblast model systems.

scholarly journals IgSF11 homophilic adhesion proteins promote layer-specific synaptic assembly of the cortical interneuron subtype

2021 ◽  
Vol 7 (29) ◽  
pp. eabf1600
Author(s):  
Yasufumi Hayano ◽  
Yugo Ishino ◽  
Jung Ho Hyun ◽  
Carlos G. Orozco ◽  
André Steinecke ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Pyramidal Neurons ◽  
Cell Types ◽  
Network Activity ◽  
Local Network ◽  
Immunoglobulin Superfamily ◽  
Specific Cell ◽  
Loss Of Function ◽  
Adhesion Proteins ◽  
Homophilic Adhesion

The most prominent structural hallmark of the mammalian neocortical circuitry is the layer-based organization of specific cell types and synaptic inputs. Accordingly, cortical inhibitory interneurons (INs), which shape local network activity, exhibit subtype-specific laminar specificity of synaptic outputs. However, the underlying molecular mechanisms remain unknown. Here, we demonstrate that Immunoglobulin Superfamily member 11 (IgSF11) homophilic adhesion proteins are preferentially expressed in one of the most distinctive IN subtypes, namely, chandelier cells (ChCs) that specifically innervate axon initial segments of pyramidal neurons (PNs), and their synaptic laminar target. Loss-of-function experiments in either ChCs or postsynaptic cells revealed that IgSF11 is required for ChC synaptic development in the target layer. While overexpression of IgSF11 in ChCs enlarges ChC presynaptic boutons, expressing IgSF11 in nontarget layers induces ectopic ChC synapses. These findings provide evidence that synapse-promoting adhesion proteins, highly localized to synaptic partners, determine the layer-specific synaptic connectivity of the cortical IN subtype.

scholarly journals Integrating High-Throughput Approaches and in vitro Human Trophoblast Models to Decipher Mechanisms Underlying Early Human Placenta Development

2021 ◽  
Vol 9 ◽  
Author(s):  
Bum-Kyu Lee ◽  
Jonghwan Kim
Keyword(s):  
High Throughput ◽  
Human Placenta ◽  
Molecular Mechanisms ◽  
Molecular Level ◽  
Cell Types ◽  
Model Systems ◽  
Extravillous Trophoblast ◽  
Human Trophoblast ◽  
Early Human

The placenta is a temporary but pivotal organ for human pregnancy. It consists of multiple specialized trophoblast cell types originating from the trophectoderm of the blastocyst stage of the embryo. While impaired trophoblast differentiation results in pregnancy disorders affecting both mother and fetus, the molecular mechanisms underlying early human placenta development have been poorly understood, partially due to the limited access to developing human placentas and the lack of suitable human in vitro trophoblast models. Recent success in establishing human trophoblast stem cells and other human in vitro trophoblast models with their differentiation protocols into more specialized cell types, such as syncytiotrophoblast and extravillous trophoblast, has provided a tremendous opportunity to understand early human placenta development. Unfortunately, while high-throughput research methods and omics tools have addressed numerous molecular-level questions in various research fields, these tools have not been widely applied to the above-mentioned human trophoblast models. This review aims to provide an overview of various omics approaches that can be utilized in the study of human in vitro placenta models by exemplifying some important lessons obtained from omics studies of mouse model systems and introducing recently available human in vitro trophoblast model systems. We also highlight some key unknown questions that might be addressed by such techniques. Integrating high-throughput omics approaches and human in vitro model systems will facilitate our understanding of molecular-level regulatory mechanisms underlying early human placenta development as well as placenta-associated complications.

scholarly journals Single-Cell Genomics: Catalyst for Cell Fate Engineering

2021 ◽  
Vol 9 ◽  
Author(s):  
Boxun Li ◽  
Gary C. Hon
Keyword(s):  
Single Cell ◽  
Cell Fate ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Cellular Heterogeneity ◽  
State Transitions ◽  
Small Scale ◽  
Specific Cell ◽  
Direct Reprogramming ◽  
Cell State

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.

Alveolus formation: what have we learned from genetic studies?

2004 ◽  
Vol 97 (4) ◽  
pp. 1543-1548 ◽  
Author(s):  
Cong Yan ◽  
Hong Du
Keyword(s):  
Molecular Mechanisms ◽  
Environmental Changes ◽  
Cell Types ◽  
Model Systems ◽  
Normal Lung ◽  
Aberrant Expression ◽  
Genetic Studies ◽  
Basic Functions ◽  
Pathogen Clearance ◽  
Alveolar Formation

The respiratory system has two basic functions: air exchange and pathogen clearance. The conducting airway and alveolar parenchyma are the basic structures to fulfill these functions during respiratory cycles. In humans, there are ∼40 cell types in the lung that coordinately work together through various structural and signaling molecules. These molecules are vital for maintaining normal lung functions in response to environmental changes. Aberrant expression of these molecules can jeopardize human health and cause various pulmonary diseases. In this article, we will review some recent progress made in the pulmonary field, using genetic animal model systems to elucidate molecular mechanisms that are important for alveolar formation and lung diseases.

UV absorption microspectrophotometry of plant cell walls in relation to biodegradation

1992 ◽  
Vol 50 (1) ◽  
pp. 864-865
Author(s):  
D.E. Akin ◽  
L.L. Rigsby ◽  
W.S. Borneman ◽  
R.D. Hartley
Keyword(s):  
Phenolic Compounds ◽  
Plant Cell ◽  
Cell Walls ◽  
Cell Types ◽  
Uv Absorption ◽  
Specific Cell ◽  
Plant Cell Walls ◽  
Plant Fiber ◽  
Efficient Utilization ◽  
Microbial Utilization

A major limitation to the biodegradation of plant cell walls is the presence of phenolic compounds, which covalently link to carbohydrates and render these potentially digestible components unavailable for microbial utilization. A more detailed understanding of phenolic compounds and their association within specific cell types is required for development of strategies to enhance biodegradation of plant fiber for efficient utilization of foods and feeds. UV absorption microspectrophotometry was employed to characterize the phenolics within cell walls of a series of plants with different biodegradabilities. Scanning electron microscopy was used to assess the degradation of specific cell types incubated with fiber-digesting microorganisms from the rumen ecosystem.

Pituitary ontogeny of the Snell dwarf mouse reveals Pit-1-independent and Pit-1-dependent origins of the thyrotrope

Development ◽  
1994 ◽  
Vol 120 (3) ◽  
pp. 515-522 ◽  
Author(s):  
S.C. Lin ◽  
S. Li ◽  
D.W. Drolet ◽  
M.G. Rosenfeld
Keyword(s):  
Molecular Mechanisms ◽  
Cell Types ◽  
Cell Phenotype ◽  
Specific Cell ◽  
Mutant Form ◽  
Wild Type ◽  
Pou Domain ◽  
Distinct Cell ◽  
Snell Dwarf ◽  
Dwarf Mice

The anterior pituitary provides a model to study the molecular mechanisms responsible for emergence of distinct cell types within an organ. Dwarf mice (Snell) that express a mutant form of the tissue-specific POU-domain transcription factor Pit-1 fail to generate three cell types, including the thyrotrope (S. Li, E. B. Crenshaw, E. J. Rawson, D. S. Simmons, L. Swanson and M. G. Rosenfeld (1990), Nature 347, 528–533). Analyses of wild-type and Pit-1-defective mice, presented here, have revealed that thyrotropes unexpectedly arise from two independent cell populations. The first population is Pit-1-independent and appears on e12 in the rostral tip of the developing gland, but phenotypically disappears by the day of birth. The second is Pit-1-dependent and arises subsequently in the caudomedial portion of the developing gland (e15.5), following the initial expression of Pit-1 in this region. The failure of caudomedial thyrotrope cells to appear in the Snell dwarf, and the observation that Pit-1 can bind to and transactivate the TSH beta promoter, apparently enhanced by its phosphorylation, suggests that Pit-1 is directly required for the appearance of this distinct population that serves as the precursors of the mature thyrotrope cell type. These data suggest that different molecular mechanisms, based on the actions of distinct transcription factors, can serve to independently generate a specific cell phenotype during mammalian organogenesis.

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