Tail Regeneration in Xenopus laevis as a Model for Understanding Tissue Repair

2008 ◽  
Vol 87 (9) ◽  
pp. 806-816 ◽  
Author(s):  
A.-S. Tseng ◽  
M. Levin

Augmentation of regenerative ability is a powerful strategy being pursued for the biomedical management of traumatic injury, cancer, and degeneration. While considerable attention has been focused on embryonic stem cells, it is clear that much remains to be learned about how somatic cells may be controlled in the adult organism. The tadpole of the frog Xenopus laevis is a powerful model system within which fundamental mechanisms of regeneration are being addressed. The tadpole tail contains spinal cord, muscle, vasculature, and other terminally differentiated cell types and can fully regenerate itself through tissue renewal—a process that is most relevant to mammalian healing. Recent insight into this process has uncovered fascinating molecular details of how a complex appendage senses injury and rapidly repairs the necessary morphology. Here, we review what is known about the chemical and bioelectric signals underlying this process and draw analogies to evolutionarily conserved pathways in other patterning systems. The understanding of this process is not only of fundamental interest for the evolutionary and cell biology of morphogenesis, but will also generate information that is crucial to the development of regenerative therapies for human tissues and organs.

Author(s):  
Antionette L. Williams ◽  
Brenda L. Bohnsack

During vertebrate embryonic development, a population of dorsal neural tube-derived stem cells, termed the neural crest (NC), undergo a series of morphogenetic changes and extensive migration to become a diverse array of cell types. Around the developing eye, this multipotent ocular NC cell population, called the periocular mesenchyme (POM), comprises migratory mesenchymal cells that eventually give rise to many of the elements in the anterior of the eye, such as the cornea, sclera, trabecular meshwork, and iris. Molecular cell biology and genetic analyses of congenital eye diseases have provided important information on the regulation of NC contributions to this area of the eye. Nevertheless, a complete understanding of the NC as a contributor to ocular development remains elusive. In addition, positional information during ocular NC migration and the molecular pathways that regulate end tissue differentiation have yet to be fully elucidated. Further, the clinical challenges of ocular diseases, such as Axenfeld-Rieger syndrome (ARS), Peters anomaly (PA) and primary congenital glaucoma (PCG), strongly suggest the need for better treatments. While several aspects of NC evolution have recently been reviewed, this discussion will consolidate the most recent current knowledge on the specification, migration, and contributions of the NC to ocular development, highlighting the anterior segment and the knowledge obtained from the clinical manifestations of its associated diseases. Ultimately, this knowledge can inform translational discoveries with potential for sorely needed regenerative therapies.


2006 ◽  
Vol 18 (8) ◽  
pp. 829 ◽  
Author(s):  
Barry D. Bavister

The distribution and functions of mitochondria in stem cells have not been examined, yet the contributions of these organelles to stem cell viability and differentiation must be vitally important in view of their critical roles in all other cell types. A key role for mitochondria in stem cells is indicated by reports that they translocate in the oocyte during fertilisation to cluster around the pronuclei and can remain in a perinuclear pattern during embryo development. This clustering appears to be essential for normal embryonic development. Because embryonic stem cells are derived from fertilised oocytes, and eventually can differentiate into ‘adult’ stem cells, it was hypothesised that mitochondrial perinuclear clustering persists through preimplantation embryo development into the stem cells, and that this localisation is indicative of stem cell pluripotency. Further, it was predicted that mitochondrial activity, as measured by respiration and adenosine triphosphate (ATP) content, would correlate with the degree of perinuclear clustering. It was also predicted that these morphological and metabolic measurements could serve as indicators of ‘stemness.’ This article reviews the distribution and metabolism of mitochondria in a model stem cell line and how this information is related to passage number, differentiation and/or senescence. In addition, it describes mitochondrial DNA deletions in oocytes and embryos that could adversely affect stem cell performance.


2021 ◽  
Vol 9 (11) ◽  
pp. 130-140
Author(s):  
M. Sithijameela ◽  
◽  
S. Ramesh Kumar ◽  
M. Sanjeetha Subin ◽  
R. Marivignesh ◽  
...  

The augmentation of regenerative capability is a powerful method for pursuing for the regulation of degeneration, traumatic injury and cancer. The tadpole, Clinotarsus curtipes and Xenopus laevis is a significant model system for addressing the fundamental regeneration mechanism that enables to understand the key aspects of regeneration medicine. The selected creatures Clinotarsus curtipes and Xenopus laevis could able to obtain both tissue regeneration and scar free healing during larval stage in spite of its predominant loss of such ability during the metamorphic process. Such transient capability associated with the evolutionary correlation with humans creates Clinotarsus curtipes and Xenopus a very good attractive model for uncovering the functional regeneration mechanisms. The study analysed the existing literatures on change in the levels of ROS that is required for the proper wnt-signaling in every regeneration system. Apart from that the paper provided the comprehensive review on the histopathological view, regeneration signals like TGFβ, FGF, BMP, Wnt etc for successful regeneration. Factors that affect the tail regeneration like O2 influx, epigenetics and HDAC activity have also been provided. Significant other such criteria like role of TRKA signaling, profiling and intracellular protein expression followed by its corresponding challenges adds value to the paper.The study presents an overview of Xenopus and Clinotarsus curtipesas a model organism for the research and highlighted the new insights.


2021 ◽  
pp. 153537022110192
Author(s):  
Gábor Tigyi ◽  
Kuan-Hung Lin ◽  
Il Ho Jang ◽  
Sue Chin Lee

Stem cells possess unique biological characteristics such as the ability to self-renew and to undergo multilineage differentiation into specialized cells. Whereas embryonic stem cells (ESC) can differentiate into all cell types of the body, somatic stem cells (SSC) are a population of stem cells located in distinct niches throughout the body that differentiate into the specific cell types of the tissue in which they reside in. SSC function mainly to restore cells as part of normal tissue homeostasis or to replenish cells that are damaged due to injury. Cancer stem-like cells (CSC) are said to be analogous to SSC in this manner where tumor growth and progression as well as metastasis are fueled by a small population of CSC that reside within the corresponding tumor. Moreover, emerging evidence indicates that CSC are inherently resistant to chemo- and radiotherapy that are often the cause of cancer relapse. Hence, major research efforts have been directed at identifying CSC populations in different cancer types and understanding their biology. Many factors are thought to regulate and maintain cell stemness, including bioactive lysophospholipids such as lysophosphatidic acid (LPA). In this review, we discuss some of the newly discovered functions of LPA not only in the regulation of CSC but also normal SSC, the similarities in these regulatory functions, and how these discoveries can pave way to the development of novel therapies in cancer and regenerative medicine.


2019 ◽  
Vol 72 (8) ◽  
pp. 1473-1476
Author(s):  
Nataliya Matolinets ◽  
Helen Sklyarova ◽  
Eugene Sklyarov ◽  
Andrii Netliukh

Introduction: Polytrauma patients have high risk of shock, septic complications and death during few years of follow-up. In recent years a lot of attention is paid to gaseous transmitters, among which are nitrogen oxide (NO) and hydrogen sulfide (H2S). It is known that the rise of NO and its metabolites levels occurs during the acute period of polytrauma. Nitric oxide and hydrogen sulfide are produced in different cell types, among which are lymphocytes. The aim: To investigate the levels of NO, NOS, iNOS, еNOS, H2S in lymphocytes lysate in patients at the moment of hospitalization and 24 hours after trauma. Materials and methods: We investigated the levels of NO, NO-synthase, inducible NO-synthase, endothelial NO-synthase, H2S in lymphocytes lysate in patients at the moment of hospitalization and 24 hours after trauma. Results: The study included 20 patients with polytrauma who were treated in the intensive care unit (ICU) of the Lviv Emergency Hospital. Tissue injury was associated with an increased production of NO, NOS, iNOS, еNOS during the acute period of polytrauma. At the same time, the level of H2S decreased by the end of the first day of traumatic injury. Conclusions: In acute period of polytrauma, significant increasing of iNOS and eNOS occurs with percentage prevalence of iNOS over eNOS on the background of H2S decreasing.


Cells ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 22
Author(s):  
Sara Marmolejo-Martínez-Artesero ◽  
David Romeo-Guitart ◽  
Vanesa Venegas ◽  
Mario Marotta ◽  
Caty Casas

Musculoskeletal injuries represent a challenging medical problem. Although the skeletal muscle is able to regenerate and recover after injury, the process engaged with conservative therapy can be inefficient, leading to a high re-injury rate. In addition, the formation of scar tissue implies an alteration of mechanical properties in muscle. There is still a need for new treatments of the injured muscle. NeuroHeal may be one option. Published studies demonstrated that it reduces muscle atrophy due to denervation and disuse. The main objective of the present work was to assess the potential of NeuroHeal to improve muscle regeneration after traumatic injury. Secondary objectives included characterizing the effect of NeuroHeal treatment on satellite cell biology. We used a rat model of sport-induced injury in the gastrocnemius and analyzed the effects of NeuroHeal on functional recovery by means of electrophysiology and tetanic force analysis. These studies were accompanied by immunohistochemistry of the injured muscle to analyze fibrosis, satellite cell state, and fiber type. In addition, we used an in vitro model to determine the effect of NeuroHeal on myoblast biology and partially decipher its mechanism of action. The results showed that NeuroHeal treatment advanced muscle fiber recovery after injury in a preclinical model of muscle injury, and significantly reduced the formation of scar tissue. In vitro, we observed that NeuroHeal accelerated the formation of myotubes. The results pave the way for novel therapeutic avenues for muscle/tendinous disorders.


2021 ◽  
Vol 22 (2) ◽  
pp. 666
Author(s):  
Toshio Takahashi

Stem cells have extensive proliferative potential and the ability to differentiate into one or more mature cell types. The mechanisms by which stem cells accomplish self-renewal provide fundamental insight into the origin and design of multicellular organisms. These pathways allow the repair of damage and extend organismal life beyond that of component cells, and they probably preceded the evolution of complex metazoans. Understanding the true nature of stem cells can only come from discovering how they are regulated. The concept that stem cells are controlled by particular microenvironments, also known as niches, has been widely accepted. Technical advances now allow characterization of the zones that maintain and control stem cell activity in several organs, including the brain, skin, and gut. Cholinergic neurons release acetylcholine (ACh) that mediates chemical transmission via ACh receptors such as nicotinic and muscarinic receptors. Although the cholinergic system is composed of organized nerve cells, the system is also involved in mammalian non-neuronal cells, including stem cells, embryonic stem cells, epithelial cells, and endothelial cells. Thus, cholinergic signaling plays a pivotal role in controlling their behaviors. Studies regarding this signal are beginning to unify our understanding of stem cell regulation at the cellular and molecular levels, and they are expected to advance efforts to control stem cells therapeutically. The present article reviews recent findings about cholinergic signaling that is essential to control stem cell function in a cholinergic niche.


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