The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform

Heinrich Jasper - One of the best experts on this subject based on the ideXlab platform.

  • AWD regulates timed activation of BMP signaling in intestinal stem cells to maintain tissue homeostasis
    Nature Communications, 2019
    Co-Authors: Xiaoyu Tracy Cai, Abu Safyan, Jennifer Gawlik, George Pyrowolakis, Hongjie Li, Heinrich Jasper
    Abstract:

    Precise control of stem cell (SC) proliferation ensures tissue homeostasis. In the Drosophila intestine, injury-Induced Regeneration involves initial activation of intestinal SC (ISC) proliferation and subsequent return to quiescence. These two phases of the regenerative response are controlled by differential availability of the BMP type I receptor Thickveins (Tkv), yet how its expression is dynamically regulated remains unclear. Here we show that during homeostasis, the E3 ubiquitin ligase Highwire and the ubiquitin-proteasome system maintain low Tkv protein expression. After ISC activation, Tkv is stabilized by proteasome inhibition and undergoes endocytosis due to the induction of the nucleoside diphosphate kinase Abnormal Wing Disc (AWD). Tkv internalization is required for the activation of the Smad protein Mad, and for the return to quiescence after a regenerative episode. Our data provide insight into the mechanisms ensuring tissue homeostasis by dynamic control of somatic stem cell activity.Regeneration after injury in the Drosophila intestine involves early activation of intestinal stem cells (ISCs) and subsequent return to quiescence. Here the authors show that return to quiescence by ISCs involves BMP Type I receptor Tkv protein stabilization along with AWD mediated internalization into endocytic vesicles.

  • AWD regulates timed activation of BMP signaling in intestinal stem cells to maintain tissue homeostasis.
    Nature communications, 2019
    Co-Authors: Xiaoyu Tracy Cai, Abu Safyan, Jennifer Gawlik, George Pyrowolakis, Heinrich Jasper
    Abstract:

    Precise control of stem cell (SC) proliferation ensures tissue homeostasis. In the Drosophila intestine, injury-Induced Regeneration involves initial activation of intestinal SC (ISC) proliferation and subsequent return to quiescence. These two phases of the regenerative response are controlled by differential availability of the BMP type I receptor Thickveins (Tkv), yet how its expression is dynamically regulated remains unclear. Here we show that during homeostasis, the E3 ubiquitin ligase Highwire and the ubiquitin-proteasome system maintain low Tkv protein expression. After ISC activation, Tkv is stabilized by proteasome inhibition and undergoes endocytosis due to the induction of the nucleoside diphosphate kinase Abnormal Wing Disc (AWD). Tkv internalization is required for the activation of the Smad protein Mad, and for the return to quiescence after a regenerative episode. Our data provide insight into the mechanisms ensuring tissue homeostasis by dynamic control of somatic stem cell activity.

Ioannis V. Yannas - One of the best experts on this subject based on the ideXlab platform.

  • Regeneration of Skin
    Tissue and Organ Regeneration in Adults, 2014
    Co-Authors: Ioannis V. Yannas
    Abstract:

    The full-thickness excisional dermis-free defect is suitable for experimental study of Induced Regeneration (synthesis) of skin and of its tissue components using a variety of reactants that are implanted in the defect.

  • common features of optimal collagen scaffolds that disrupt wound contraction and enhance Regeneration both in peripheral nerves and in skin
    Biomaterials, 2012
    Co-Authors: Eric C Soller, Dimitrios S Tzeranis, Peter T C So, Ioannis V. Yannas
    Abstract:

    Abstract The adult mammal responds to severe injury of most organs spontaneously by wound contraction and scar formation, rather than by Regeneration. In severe skin wounds, the ability of porous collagen scaffolds to induce Regeneration was found to correlate strongly with a reduction in wound contraction rate. Here, we present quantitative evidence of a similar positive relationship between the extent of disruption of tissue contraction and quality of peripheral nerve Regeneration in transected rat peripheral nerves. Our observations suggest that porous collagen scaffolds enhance Regeneration both in injured adult skin and peripheral nerves by disrupting the formation of a contractile cell capsule at the edges of the wound. Preliminary observations made with other injured organs support the hypothesis that capsules or clusters of contractile cells impose a universal mechanical barrier during wound healing which, if disrupted appropriately, enhances the quality of Induced Regeneration in a wider range of organs.

  • Induced Regeneration of Skin and Peripheral Nerves in the Adult
    The Diabetic Foot, 2012
    Co-Authors: Eric C Soller, Ioannis V. Yannas
    Abstract:

    Injury to the mammalian fetus is reversible during early stages of gestation and the spontaneous wound response is capable of restoring the structure and function of the original organ, a process called Regeneration. By contrast, the unimpaired response to severe injury in adult mammals is an irreversible repair process leading to closure of the injured site by contraction and formation of scar, a nonphysiological tissue. The consequences of irreversible healing at the organ scale are far-reaching: they typically result in an essentially nonfunctional organ.

  • Tissue and organ Regeneration in adults
    2001
    Co-Authors: Ioannis V. Yannas
    Abstract:

    Preface. 1. The Irreversibility of Injury. 2. Nonregenerative Tissues. 3. Anatomically Well-Defined Defects. 4. The Defect Closure Rule. 5. Regeneration of Skin. 6. Regeneration of a Peripheral Nerve. 7. Irreducible Processes for Synthesis of Skin and Peripheral Nerves. 8. The Antagonistic Relation Between Contraction and Regeneration. 9. Kinetics and Mechanism I. Spontaneous Healing. 10. Kinetics and Mechanism II. Induced Regeneration. Appendix A. Method of estimation of critical axon elongation of an arbitrary tubulated device bridging two nerve stumps. Index.

  • Tissue Regeneration by use of collagen-glycosaminoglycan copolymers.
    Clinical materials, 1992
    Co-Authors: Ioannis V. Yannas
    Abstract:

    Simple chemical analogs of extracellular matrices have been synthesized by graft copolymerization of a glycosaminoglycan on to type I collagen. A few of these collagen-graft-glycosaminoglycan copolymers (CG copolymers) have diverted decisively the kinetics and mechanism of skin wound healing in animals and humans away from contraction and scar synthesis, towards the direction of skin Regeneration. Detailed animal studies show that CG copolymers show maximum biological activity when the average pore diameter and the degradation rate in collagenase are controlled within critical limits. When seeded with a minimum number of cells these active copolymers induce Regeneration of skin, including synthesis of a new epidermis and a new dermis in the correct anatomical relationship. Certain unseeded copolymers have also Induced Regeneration of peripheral nerve. Another copolymer has Induced Regeneration of the knee meniscus. The unusual biological activity of these copolymers has led to extensive, successful clinical testing of novel medical devices for the treatment of skin loss with severely burned patients.

Maryam Crabbe-mann - One of the best experts on this subject based on the ideXlab platform.

  • Bioinspired scaffold Induced Regeneration of neural tissue
    European Polymer Journal, 2019
    Co-Authors: Esra Altun, Mehmet Onur Aydogdu, Sine Özmen Toğay, Ahmet Zeki Sengil, Nazmi Ekren, Merve Erginer Haskoylu, Ebru Toksoy Oner, Nese A. Altuncu, Gürkan Öztürk, Maryam Crabbe-mann
    Abstract:

    Abstract In the last decade, nerve tissue engineering has attracted much attention due to the incapability of self-Regeneration. Nerve tissue Regeneration is mainly based on scaffold Induced nanofibrous structures using both bio and synthetic polymers. The produced nanofibrous scaffolds have to be similar to the natural extracellular matrix and should provide an appropriate environment for cells to attach onto. Nanofibrous scaffolds can support or regenerate cells of tissue. Electrospinning is an ideal method for producing the nanofibrous scaffolds. In this study, Bacterial cellulose (BC)/Poly (e-caprolactone) (PCL) blend nanofibrous scaffolds were successfully prepared by electrospinning for nerve tissue Induced repair. The produced nanofibrous scaffolds contain well defined interconnected nanofiber networks with hollow micro/nanobeads. Firstly, in-vitro biocompatibilities of nanofibrous scaffolds were tested with L2929 murine fibroblasts and improved cell adhesion and proliferation was observed with polymer blends compared with PCL only. The primary cell culture was performed with dorsal root ganglia (DRG) cells on nanofibrous samples and the samples were found suitable for enhancing neural growth and neurite outgrowth. Based on these results, the BC/PCL (50:50 wt.%) nanofibrous scaffolds exhibited nerve-like branching and are excellent candidate for potential biomimetic applications in nerve tissue engineering Regeneration.

Irin Constance Maier - One of the best experts on this subject based on the ideXlab platform.

  • differential effects of anti nogo a antibody treatment and treadmill training in rats with incomplete spinal cord injury
    Brain, 2009
    Co-Authors: Lisa Schnell, Irin Constance Maier, Ronaldo M Ichiyama, Gregoire Courtine, Igor Lavrov, Reggie V Edgerton
    Abstract:

    Locomotor training on treadmills can improve recovery of stepping in spinal cord injured animals and patients. Likewise, lesioned rats treated with antibodies against the myelin associated neurite growth inhibitory protein, Nogo-A, showed increased Regeneration, neuronal reorganization and behavioural improvements. A detailed kinematic analysis showed that the hindlimb kinematic patterns that developed in anti-Nogo-A antibody treated versus treadmill trained spinal cord injured rats were significantly different. The synchronous combined treatment group did not show synergistic effects. This lack of synergistic effects could not be explained by an increase in pain perception, sprouting of calcitonin gene-related peptide (CGRP) positive fibres or by interference of locomotor training with anti-Nogo-A antibody Induced Regeneration and sprouting of descending fibre tracts. The differential mechanisms leading to behavioural recovery during task-specific training and in Regeneration or plasticity enhancing therapies have to be taken into account in designing combinatorial therapies so that their potential positive interactive effects can be fully expressed.

Riki Kawaguchi - One of the best experts on this subject based on the ideXlab platform.

  • analysis of the immune response to sciatic nerve injury identifies efferocytosis as a key mechanism of nerve debridement
    eLife, 2020
    Co-Authors: Ashley L Kalinski, Riki Kawaguchi, Choya Yoon, Lucas D Huffman, Patrick C Duncker, Rafi Kohen, Ryan Passino, Hannah Hafner, Craig A Johnson, Kevin S Carbajal
    Abstract:

    Sciatic nerve crush injury triggers sterile inflammation within the distal nerve and axotomized dorsal root ganglia (DRGs). Granulocytes and pro-inflammatory Ly6Chigh monocytes infiltrate the nerve first, and rapidly give way to Ly6Cnegative inflammation-resolving macrophages. In axotomized DRGs, few hematogenous leukocytes are detected and resident macrophages acquire a ramified morphology. Single-cell RNA-sequencing of injured sciatic nerve identifies five macrophage subpopulations, repair Schwann cells, and mesenchymal precursor cells. Macrophages at the nerve crush site are molecularly distinct from macrophages associated with Wallerian degeneration. In the injured nerve, macrophages 'eat' apoptotic leukocytes, a process called efferocytosis, and thereby promote an anti-inflammatory milieu. Myeloid cells in the injured nerve, but not axotomized DRGs, strongly express receptors for the cytokine GM-CSF. In GM-CSF deficient (Csf2-/-) mice, inflammation resolution is delayed and conditioning-lesion Induced Regeneration of DRG neuron central axons is abolished. Thus, carefully orchestrated inflammation resolution in the nerve is required for conditioning-lesion Induced neurorepair.

  • sox11 expression promotes Regeneration of some retinal ganglion cell types but kills others
    Neuron, 2017
    Co-Authors: Michael W Norsworthy, Fengfeng Bei, Riki Kawaguchi, Qing Wang, Nicholas M Tran, Benedikt Brommer, Yiming Zhang, Chen Wang, Joshua R Sanes
    Abstract:

    At least 30 types of retinal ganglion cells (RGCs) send distinct messages through the optic nerve to the brain. Available strategies of promoting axon Regeneration act on only some of these types. Here we tested the hypothesis that overexpressing developmentally important transcription factors in adult RGCs could reprogram them to a "youthful" growth-competent state and promote Regeneration of other types. From a screen of transcription factors, we identified Sox11 as one that could induce substantial axon Regeneration. Transcriptome profiling indicated that Sox11 activates genes involved in cytoskeletal remodeling and axon growth. Remarkably, α-RGCs, which preferentially regenerate following treatments such as Pten deletion, were killed by Sox11 overexpression. Thus, Sox11 promotes Regeneration of non-α-RGCs, which are refractory to Pten deletion-Induced Regeneration. We conclude that Sox11 can reprogram adult RGCs to a growth-competent state, suggesting that different growth-promoting interventions promote Regeneration in distinct neuronal types.