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Claudia Marcela Arenas Gómez, Andrea Gómez Molina, Juliana D Zapata, Jean Paul Delgado
Appendage regeneration is one of the most compelling phenomena in regenerative biology and is extensively studied in axolotls and newts. However, the regenerative capacity in other families of salamanders remains poorly described. Here we characterize the limb regeneration process in Bolitoglossa ramosi, a direct-developing terrestrial salamander of the plethodontid family. We (1) describe the major morphological features at different stages of limb regeneration, (2) show that appendage regeneration in a terrestrial salamander varies from other amphibians and (3) show that limb regeneration in this species is considerably slower than in axolotls and newts (95 days post-amputation for complete regeneration) despite having a significantly smaller genome size than axolotls or newts...
August 2017: Regeneration
Alexander James Hale, Ali Kiai, Jelte Sikkens, Jeroen den Hertog
Zebrafish are able to completely regrow their caudal fin-folds after amputation. Following injury, wound healing occurs, followed by the formation of a blastema, which produces cells to replace the lost tissue in the final phase of regenerative outgrowth. Here we show that, surprisingly, the phosphatase and tumor suppressor Pten, an antagonist of phosphoinositide-3-kinase (PI3K) signaling, is required for zebrafish caudal fin-fold regeneration. We found that homozygous knock-out mutant (ptena-/-ptenb-/- ) zebrafish embryos, lacking functional Pten, did not regenerate their caudal fin-folds...
August 2017: Regeneration
Anneke Horstman, Marian Bemer, Kim Boutilier
Somatic embryogenesis is a form of induced plant cell totipotency where embryos develop from somatic or vegetative cells in the absence of fertilization. Somatic embryogenesis can be induced in vitro by exposing explants to stress or growth regulator treatments. Molecular genetics studies have also shown that ectopic expression of specific embryo- and meristem-expressed transcription factors or loss of certain chromatin-modifying proteins induces spontaneous somatic embryogenesis. We begin this review with a general description of the major developmental events that define plant somatic embryogenesis and then focus on the transcriptional regulation of this process in the model plant Arabidopsis thaliana (arabidopsis)...
August 2017: Regeneration
David L Stocum
This review explores the historical and current state of our knowledge about urodele limb regeneration. Topics discussed are (1) blastema formation by the proteolytic histolysis of limb tissues to release resident stem cells and mononucleate cells that undergo dedifferentiation, cell cycle entry and accumulation under the apical epidermal cap. (2) The origin, phenotypic memory, and positional memory of blastema cells. (3) The role played by macrophages in the early events of regeneration. (4) The role of neural and AEC factors and interaction between blastema cells in mitosis and distalization...
August 2017: Regeneration
Michael Levin, Junji Morokuma, Joshua Finkelstein
No abstract text is available yet for this article.
August 2017: Regeneration
Ronald Sluys, Giacinta A Stocchino
Available evidence strongly suggests that alternative, Earth-bound explanations should be sought first for the occurrence of a single bipolar planarian flatworm returning from space travel. Double-headed worms have been amply documented as arising under experimental conditions as well as spontaneously in stock cultures of planarians.
August 2017: Regeneration
Juan Manuel González-Rosa, Caroline E Burns, C Geoffrey Burns
Cardiovascular disease is the leading cause of death worldwide. Compared to other organs such as the liver, the adult human heart lacks the capacity to regenerate on a macroscopic scale after injury. As a result, myocardial infarctions are responsible for approximately half of all cardiovascular related deaths. In contrast, the zebrafish heart regenerates efficiently upon injury through robust myocardial proliferation. Therefore, deciphering the mechanisms that underlie the zebrafish heart's endogenous regenerative capacity represents an exciting avenue to identify novel therapeutic strategies for inducing regeneration of the human heart...
June 2017: Regeneration
Lindsay A Dawson, Ling Yu, Mingquan Yan, Luis Marrero, Paula P Schanes, Connor Dolan, Maegan Pela, Britta Petersen, Manjong Han, Ken Muneoka
Regeneration of mammalian limbs is restricted to amputation of the distal digit tip, the terminal phalanx (P3). The adjacent skeletal element, the middle phalanx (P2), has emerged as a model system to investigate regenerative failure and as a site to test approaches aimed at enhancing regeneration. We report that exogenous application of bone morphogenetic protein 2 (BMP2) stimulates the formation of a transient cartilaginous callus distal to the amputation plane that mediates the regeneration of the amputated P2 bone...
June 2017: Regeneration
Bo Hu, Guifang Zhang, Wu Liu, Jianmin Shi, Hua Wang, Meifang Qi, Jiqin Li, Peng Qin, Ying Ruan, Hai Huang, Yijing Zhang, Lin Xu
In tissue culture, the formation of callus from detached explants is a key step in plant regeneration; however, the regenerative abilities in different species are variable. While nearly all parts of organs of the dicot Arabidopsis thaliana are ready for callus formation, mature regions of organs in monocot rice (Oryza sativa) and other cereals are extremely unresponsive to tissue culture. Whether there is a common molecular mechanism beyond these different regenerative phenomena is unclear. Here we show that the Arabidopsis and rice use different regeneration-competent cells to initiate callus, whereas the cells all adopt WUSCHEL-RELATED HOMEOBOX 11 (WOX11) and WOX5 during cell fate transition...
June 2017: Regeneration
Mathias Møller Thygesen, Mikkel Mylius Rasmussen, Jesper Guldsmed Madsen, Michael Pedersen, Henrik Lauridsen
The Mexican axolotl (Ambystoma mexicanum) is an important model species in regenerative biology. Traditionally, axolotls are anesthetized using benzocaine or MS-222, both of which act to inhibit voltage gated sodium channels thereby preventing action potential propagation. In some neurophysiological experiments this is not desirable; therefore we tested propofol as an alternative anesthetic in the axolotl. We evaluated benzocaine, MS-222, and propofol's cardiovascular effects, effects on action potential propagation in the spinal cord, and gross limb regenerative effects...
June 2017: Regeneration
Junji Morokuma, Fallon Durant, Katherine B Williams, Joshua M Finkelstein, Douglas J Blackiston, Twyman Clements, David W Reed, Michael Roberts, Mahendra Jain, Kris Kimel, Sunia A Trauger, Benjamin E Wolfe, Michael Levin
Regeneration is regulated not only by chemical signals but also by physical processes, such as bioelectric gradients. How these may change in the absence of the normal gravitational and geomagnetic fields is largely unknown. Planarian flatworms were moved to the International Space Station for 5 weeks, immediately after removing their heads and tails. A control group in spring water remained on Earth. No manipulation of the planaria occurred while they were in orbit, and space-exposed worms were returned to our laboratory for analysis...
April 2017: Regeneration
Luis Marrero, Jennifer Simkin, Mimi Sammarco, Ken Muneoka
The regeneration blastema which forms following amputation of the mouse digit tip is composed of undifferentiated cells bound together by an organized network of fibers. A monoclonal antibody (ER-TR7) that identifies extracellular matrix (ECM) fibers produced by fibroblast reticular cells during lymphoid organogenesis was used to characterize the ECM of the digit, the blastema, and the regenerate. Digit fibroblast reticular cells produce an ER-TR7(+) ECM network associated with different tissues and represent a subset of loose connective tissue fibroblasts...
April 2017: Regeneration
Bénoni Boilly, Yolande Boilly-Marer, Alexandra E Bely
An important goal for understanding regeneration is determining how polarity is conferred to the regenerate. Here we review findings in two groups of polychaete annelids that implicate the ventral nerve cord in assigning dorso-ventral polarity, and specifically ventral identity, to the regenerate. In nereids, surgical manipulations indicate that parapodia develop where dorsal and ventral body wall territories contact. Without a nerve cord at the wound site, the regenerate differentiates no evident polarity (with no parapodia) and only dorsal identity, while with two nerve cords the regenerate develops a twinned dorso-ventral axis (with four parapodia per segment instead of the normal two)...
April 2017: Regeneration
Anthony L Mescher
This review provides a concise summary of the changing phenotypes of macrophages and fibroblastic cells during the local inflammatory response, the onset of tissue repair, and the resolution of inflammation which follow injury to an organ. Both cell populations respond directly to damage and present coordinated sequences of activation states which determine the reparative outcome, ranging from true regeneration of the organ to fibrosis and variable functional deficits. Recent work with mammalian models of organ regeneration, including regeneration of full-thickness skin, hair follicles, ear punch tissues, and digit tips, is summarized and the roles of local immune cells in these systems are discussed...
April 2017: Regeneration
Victor S Tapia, Mauricio Herrera-Rojas, Juan Larrain
Xenopus laevis tadpoles can regenerate the spinal cord after injury but this capability is lost during metamorphosis. Comparative studies between pre-metamorphic and metamorphic Xenopus stages can aid towards understanding the molecular mechanisms of spinal cord regeneration. Analysis of a previous transcriptome-wide study suggests that, in response to injury, the JAK-STAT pathway is differentially activated in regenerative and non-regenerative stages. We characterized the activation of the JAK-STAT pathway and found that regenerative tadpoles have an early and transient activation...
February 2017: Regeneration
Kenneth D Birnbaum, François Roudier
Plants have a high intrinsic capacity to regenerate from adult tissues, with the ability to reprogram adult cell fates. In contrast, epigenetic mechanisms have the potential to stabilize cell identity and maintain tissue organization. The question is whether epigenetic memory creates a barrier to reprogramming that needs to be erased or circumvented in plant regeneration. Early evidence suggests that, while chromatin dynamics impact gene expression in the meristem, a lasting constraint on cell fate is not established until late stages of plant cell differentiation...
February 2017: Regeneration
Charles W Melnyk
For millennia, people have cut and joined different plants together through a process known as grafting. The severed tissues adhere, the cells divide and the vasculature differentiates through a remarkable process of regeneration between two genetically distinct organisms as they become one. Grafting is becoming increasingly important in horticulture where it provides an efficient means for asexual propagation. Grafting also combines desirable roots and shoots to generate chimeras that are more vigorous, more pathogen resistant and more abiotic stress resistant...
February 2017: Regeneration
Michelle E Deochand, Taylor R Birkholz, Wendy S Beane
While tissue regeneration is typically studied using standard injury models, in nature injuries vary greatly in the amount and location of tissues lost. Planarians have the unique ability to regenerate from many different injuries (including from tiny fragments with no brain), allowing us to study the effects of different injuries on regeneration timelines. We followed the timing of regeneration for one organ, the eye, after multiple injury types that involved tissue loss (single- and double-eye ablation, and decapitation) in Schmidtea mediterranea...
August 2016: Regeneration
Jingjing Li, Siwei Zhang, Enrique Amaya
Survival of any living organism critically depends on its ability to repair and regenerate damaged tissues and/or organs during its lifetime following injury, disease, or aging. Various animal models from invertebrates to vertebrates have been used to investigate the molecular and cellular mechanisms of wound healing and tissue regeneration. It is hoped that such studies will form the framework for identifying novel clinical treatments that will improve the healing and regenerative capacity of humans. Amongst these models, Xenopus stands out as a particularly versatile and powerful system...
August 2016: Regeneration
Abdul Kareem, Dhanya Radhakrishnan, Yash Sondhi, Mohammed Aiyaz, Merin V Roy, Kaoru Sugimoto, Kalika Prasad
While in the movie Deadpool it is possible for a human to recreate an arm from scratch, in reality plants can even surpass that. Not only can they regenerate lost parts, but also the whole plant body can be reborn from a few existing cells. Despite the decades old realization that plant cells possess the ability to regenerate a complete shoot and root system, it is only now that the underlying mechanisms are being unraveled. De novo plant regeneration involves the initiation of regenerative mass, acquisition of the pluripotent state, reconstitution of stem cells and assembly of regulatory interactions...
August 2016: Regeneration
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