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.

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.

The complexity and evolution of the plastid-division machinery

2010 ◽  
Vol 38 (3) ◽  
pp. 783-788 ◽  
Author(s):  
Jodi Maple ◽  
Simon Geir Møller
Keyword(s):  
Molecular Mechanisms ◽  
Environmental Changes ◽  
Cell Types ◽  
Cellular Level ◽  
Plastid Division ◽  
Bacterial Cell Division ◽  
Metabolic Functions ◽  
Photosynthetic Eukaryotes ◽  
Metabolic Output ◽  
Host Nucleus

Plastids are vital organelles, fulfilling important metabolic functions that greatly influence plant growth and productivity. In order to both regulate and harness the metabolic output of plastids, it is vital that the process of plastid division is carefully controlled. This is essential, not only to ensure persistence in dividing plant cells and that optimal numbers of plastids are obtained in specialized cell types, but also to allow the cell to act in response to developmental signals and environmental changes. How this control is exerted by the host nucleus has remained elusive. Plastids evolved by endosymbiosis and during the establishment of a permanent endosymbiosis they retained elements of the bacterial cell-division machinery. Through evolution the photosynthetic eukaryotes have increased dramatically in complexity, from single-cell green algae to multicellular non-vascular and vascular plants. Reflected with this is an increasing complexity of the division machinery and recent findings also suggest increasing complexity in the molecular mechanisms used by the host cell to control the process of plastid division. In the present paper, we explore the current understanding of the process of plastid division at the molecular and cellular level, with particular respect to the evolution of the division machinery and levels of control exerted on the process.

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 Vascular Regulation of Hematopoietic Stem Cell Homeostasis, Regeneration, and Aging

2021 ◽  
Author(s):  
Pradeep Ramalingam ◽  
Jason M. Butler ◽  
Michael G. Poulos
Keyword(s):  
Stem Cell ◽  
Cell Fate ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Dynamic Imaging ◽  
Model Systems ◽  
Hematopoietic Stem ◽  
Perivascular Cell ◽  
Cell Fate Decisions ◽  
Vascular Regulation

Abstract Purpose of Review Hematopoietic stem cells (HSCs) sit at the top of the hierarchy that meets the daily burden of blood production. HSC maintenance relies on extrinsic cues from the bone marrow (BM) microenvironment to balance stem cell self-renewal and cell fate decisions. In this brief review, we will highlight the studies and model systems that define the centralized role of BM vascular endothelium in modulating HSC activity in health and stress. Recent Findings The BM microenvironment is composed of a diverse array of intimately associated vascular and perivascular cell types. Recent dynamic imaging studies, coupled with single-cell RNA sequencing (scRNA-seq) and functional readouts, have advanced our understanding of the HSC-supportive cell types and their cooperative mechanisms that govern stem cell fate during homeostasis, regeneration, and aging. These findings have established complex and discrete vascular microenvironments within the BM that express overlapping and unique paracrine signals that modulate HSC fate. Summary Understanding the spatial and reciprocal HSC-niche interactions and the molecular mechanisms that govern HSC activity in the BM vascular microenvironment will be integral in developing therapies aimed at ameliorating hematological disease and supporting healthy hematopoietic output.

scholarly journals MicroRNAs: Recent insights towards their role in male infertility and reproductive cancers

2019 ◽  
Vol 19 (1) ◽  
pp. 31-42 ◽  
Author(s):  
Muhammad Babar Khawar ◽  
Rabia Mehmood ◽  
Nabila Roohi
Keyword(s):  
Male Infertility ◽  
Reproductive System ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Regulatory Mechanisms ◽  
Aberrant Expression ◽  
Protein Coding ◽  
Reproductive Cancers ◽  
Post Transcriptional Regulation ◽  
Different Cell Types

Spermatogenesis is a tightly controlled, multi-step process in which mature spermatozoa are produced. Disruption of regulatory mechanisms in spermatogenesis can lead to male infertility, various diseases of male reproductive system, or even cancer. The spermatogenic impairment in infertile men can be associated with different etiologies, and the exact molecular mechanisms are yet to be determined. MicroRNAs (miRNAs) are a type of non-protein coding RNAs, about 22 nucleotides long, with an essential role in post-transcriptional regulation. miRNAs have been recognized as important regulators of various biological processes, including spermatogenesis. The aim of this review is to summarize the recent literature on the role of miRNAs in spermatogenesis, male infertility and reproductive cancers, and to evaluate their potential in diagnosis, prognosis and therapy of disease. Experimental evidence shows that aberrant expression of miRNAs affects spermatogenesis at multiple stages and in different cell types, most often resulting in infertility. In more severe cases, dysregulation of miRNAs leads to cancer. miRNAs have enormous potential to be used as diagnostic and prognostic markers as well as therapeutic targets in male infertility and reproductive system diseases. However, to exploit this potential fully, we need a better understanding of miRNA-mediated regulation of spermatogenesis, including the characterization of yet unidentified miRNAs and related regulatory mechanisms.

scholarly journals Autophagy and LAP in the Fight against Fungal Infections: Regulation and Therapeutics

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Vasileios Oikonomou ◽  
Giorgia Renga ◽  
Antonella De Luca ◽  
Monica Borghi ◽  
Marilena Pariano ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Fungal Infections ◽  
Cell Types ◽  
Fungal Species ◽  
Host Immune Responses ◽  
Host Protection ◽  
Pathogen Clearance ◽  
The Relationship ◽  
Broad Role

Phagocytes fight fungi using canonical and noncanonical, also called LC3-associated phagocytosis (LAP), autophagy pathways. However, the outcomes of autophagy/LAP in shaping host immune responses appear to greatly vary depending on fungal species and cell types. By allowing efficient pathogen clearance and/or degradation of inflammatory mediators, autophagy proteins play a broad role in cellular and immune homeostasis during fungal infections. Indeed, defects in autophagic machinery have been linked with aberrant host defense and inflammatory states. Thus, understanding the molecular mechanisms underlying the relationship between the different forms of autophagy may offer a way to identify drugable molecular signatures discriminating between selective recognition of cargo and host protection. In this regard, IFN-γ and anakinra are teaching examples of successful antifungal agents that target the autophagy machinery. This article provides an overview of the role of autophagy/LAP in response to fungi and in their infections, regulation, and therapeutic exploitation.

scholarly journals Kinases of the Focal Adhesion Complex Contribute to Cardiomyocyte Specification

2021 ◽  
Vol 22 (19) ◽  
pp. 10430
Author(s):  
Sacha Robert ◽  
Marcus Flowers ◽  
Brenda M. Ogle
Keyword(s):  
Stem Cells ◽  
Focal Adhesion ◽  
Pluripotent Stem Cells ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Culture Conditions ◽  
Model Systems ◽  
Critical Components

Differentiation of pluripotent stem cells to cardiomyocytes is influenced by culture conditions including the extracellular matrices or similar synthetic scaffolds on which they are grown. However, the molecular mechanisms that link the scaffold with differentiation outcomes are not fully known. Here, we determined by immunofluorescence staining and mass spectrometry approaches that extracellular matrix (ECM) engagement by mouse pluripotent stem cells activates critical components of canonical wingless/integrated (Wnt) signaling pathways via kinases of the focal adhesion to drive cardiomyogenesis. These kinases were found to be differentially activated depending on type of ECM engaged. These outcomes begin to explain how varied ECM composition of in vivo tissues with development and in vitro model systems gives rise to different mature cell types, having broad practical applicability for the design of engineered tissues.

scholarly journals Do Epigenetic Timers Control Petal Development?

2021 ◽  
Vol 12 ◽  
Author(s):  
Ruirui Huang ◽  
Tengbo Huang ◽  
Vivian F. Irish
Keyword(s):  
Gene Expression ◽  
Molecular Mechanisms ◽  
Environmental Changes ◽  
Cell Types ◽  
Epigenetic Factors ◽  
Control Of Gene Expression ◽  
Dna Accessibility ◽  
Developmental Progression ◽  
Petal Development ◽  
Incomplete Picture

Epigenetic modifications include histone modifications and DNA methylation; such modifications can induce heritable changes in gene expression by altering DNA accessibility and chromatin structure. A number of studies have demonstrated that epigenetic factors regulate plant developmental timing in response to environmental changes. However, we still have an incomplete picture of how epigenetic factors can regulate developmental events such as organogenesis. The small number of cell types and the relatively simple developmental progression required to form the Arabidopsis petal makes it a good model to investigate the molecular mechanisms driving plant organogenesis. In this minireview, we summarize recent studies demonstrating the epigenetic control of gene expression during various developmental transitions, and how such regulatory mechanisms can potentially act in petal growth and differentiation.

scholarly journals Vascular Homeostasis and Inflammation in Health and Disease—Lessons from Single Cell Technologies

2020 ◽  
Vol 21 (13) ◽  
pp. 4688 ◽  
Author(s):  
Olga Bondareva ◽  
Bilal N. Sheikh
Keyword(s):  
Single Cell ◽  
Molecular Mechanisms ◽  
Environmental Changes ◽  
Vascular System ◽  
Vascular Dysfunction ◽  
Rapid Development ◽  
Cell Types ◽  
The Body ◽  
Vascular Cells ◽  
Cell Technologies

The vascular system is critical infrastructure that transports oxygen and nutrients around the body, and dynamically adapts its function to an array of environmental changes. To fulfil the demands of diverse organs, each with unique functions and requirements, the vascular system displays vast regional heterogeneity as well as specialized cell types. Our understanding of the heterogeneity of vascular cells and the molecular mechanisms that regulate their function is beginning to benefit greatly from the rapid development of single cell technologies. Recent studies have started to analyze and map vascular beds in a range of organs in healthy and diseased states at single cell resolution. The current review focuses on recent biological insights on the vascular system garnered from single cell analyses. We cover the themes of vascular heterogeneity, phenotypic plasticity of vascular cells in pathologies such as atherosclerosis and cardiovascular disease, as well as the contribution of defective microvasculature to the development of neurodegenerative disorders such as Alzheimer’s disease. Further adaptation of single cell technologies to study the vascular system will be pivotal in uncovering the mechanisms that drive the array of diseases underpinned by vascular dysfunction.

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.

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