scholarly journals Betacellulin Regulates Peripheral Nerve Regeneration by Affecting Schwann Cell Migration and Axon Elongation

Author(s):  
Yaxian Wang ◽  
Fuchao Zhang ◽  
Yunsong Zhang ◽  
Qi Shan ◽  
Wei Liu ◽  
...  

Abstract Background Growth factors execute essential biological functions and affect various physiological and pathological processes, including peripheral nerve injury and regeneration. Our previous sequencing analysis found that betacellulin (Btc), an epidermal growth factor protein family member, showed elevated mRNA expressions in the nerve segment after rat peripheral nerve injury, implying the potential involvement of Btc during peripheral nerve repair. Methods Expression of Btc was examined in Schwann cells. The role of Btc in regulating Schwann cells was investigated by transfecting cultured cells with siRNA segment against Btc or exposed cultured cells with Btc recombinant protein, respectively. The biological functions of Schwann cell-secreted Btc on neurons were also determined. Moreover, the in vivo effect of Btc on Schwann cell migration and axon elongation after rat sciatic nerve injury were further evaluated.Results Immunostaining images and ELISA readings showed Btc was present in and secreted by Schwann cells. Transwell migration and wound healing observations showed that siRNA against Btc impeded Schwann cell migration while exogenous Btc advanced Schwann cell migration. Besides the regulating effect on Schwann cell phenotype, Btc secreted by Schwann cells might influence neuron behavior and affect axon length. In vivo evidence showed that Btc enhanced axonal regrowth and nerve regeneration after both rat sciatic nerve crush injury and transection injury. Conclusion Our findings demonstrated Btc-mediated Schwann cell-axon interactions, revealed the essential roles of Btc on Schwann cell migration and axon elongation, and implied the potential application of Btc as a regenerative strategy for treating peripheral nerve injury.

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Hongkui Wang ◽  
Ping Zhang ◽  
Jun Yu ◽  
Fuchao Zhang ◽  
Wenzhao Dai ◽  
...  

AbstractSchwann cells experience de-differentiation, proliferation, migration, re-differentiation and myelination, and participate in the repair and regeneration of injured peripheral nerves. Our previous sequencing analysis suggested that the gene expression level of matrix metalloproteinase 7 (MMP7), a Schwann cell-secreted proteolytic enzyme, was robustly elevated in rat sciatic nerve segments after nerve injury. However, the biological roles of MMP7 are poorly understood. Here, we exposed primary cultured Schwann cells with MMP7 recombinant protein and transfected siRNA against MMP7 into Schwann cells to examine the effect of exogenous and endogenous MMP7. Meanwhile, the effects of MMP7 in nerve regeneration after sciatic nerve crush in vivo were observed. Furthermore, RNA sequencing and bioinformatic analysis of Schwann cells were conducted to show the molecular mechanism behind the phenomenon. In vitro studies showed that MMP7 significantly elevated the migration rate of Schwann cells but did not affect the proliferation rate of Schwann cells. In vivo studies demonstrated that increased level of MMP7 contributed to Schwann cell migration and myelin sheaths formation after peripheral nerve injury. MMP7-mediated genetic changes were revealed by sequencing and bioinformatic analysis. Taken together, our current study demonstrated the promoting effect of MMP7 on Schwann cell migration and peripheral nerve regeneration, benefited the understanding of cellular and molecular mechanisms underlying peripheral nerve injury, and thus might facilitate the treatment of peripheral nerve regeneration in clinic.


2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Yaxian Wang ◽  
Fuchao Zhang ◽  
Yunsong Zhang ◽  
Qi Shan ◽  
Wei Liu ◽  
...  

Abstract Background Growth factors execute essential biological functions and affect various physiological and pathological processes, including peripheral nerve repair and regeneration. Our previous sequencing data showed that the mRNA coding for betacellulin (Btc), an epidermal growth factor protein family member, was up-regulated in rat sciatic nerve segment after nerve injury, implying the potential involvement of Btc during peripheral nerve regeneration. Methods Expression of Btc was examined in Schwann cells by immunostaining. The function of Btc in regulating Schwann cells was investigated by transfecting cultured cells with siRNA segment against Btc or treating cells with Btc recombinant protein. The influence of Schwann cell-secreted Btc on neurons was determined using a co-culture assay. The in vivo effects of Btc on Schwann cell migration and axon elongation after rat sciatic nerve injury were further evaluated. Results Immunostaining images and ELISA outcomes indicated that Btc was present in and secreted by Schwann cells. Transwell migration and wound healing observations showed that transfection with siRNA against Btc impeded Schwann cell migration while application of exogenous Btc advanced Schwann cell migration. Besides the regulating effect on Schwann cell phenotype, Btc secreted by Schwann cells influenced neuron behavior and increased neurite length. In vivo evidence supported the promoting role of Btc in nerve regeneration after both rat sciatic nerve crush injury and transection injury. Conclusion Our findings demonstrate the essential roles of Btc on Schwann cell migration and axon elongation and imply the potential application of Btc as a regenerative strategy for treating peripheral nerve injury.


Glia ◽  
2019 ◽  
Vol 68 (3) ◽  
pp. 670-679 ◽  
Author(s):  
Chun Yao ◽  
Yanping Chen ◽  
Jing Wang ◽  
Tianmei Qian ◽  
Wei Feng ◽  
...  

Cells ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 2497
Author(s):  
Zhong Huang ◽  
Rebecca Powell ◽  
James B. Phillips ◽  
Kirsten Haastert-Talini

Schwann cells play a crucial role in successful peripheral nerve repair and regeneration by supporting both axonal growth and myelination. Schwann cells are therefore a feasible option for cell therapy treatment of peripheral nerve injury. However, sourcing human Schwann cells at quantities required for development beyond research is challenging. Due to their availability, rapid in vitro expansion, survival, and integration within the host tissue, stem cells have attracted considerable attention as candidate cell therapies. Among them, induced pluripotent stem cells (iPSCs) with the associated prospects for personalized treatment are a promising therapy to take the leap from bench to bedside. In this critical review, we firstly focus on the current knowledge of the Schwann cell phenotype in regard to peripheral nerve injury, including crosstalk with the immune system during peripheral nerve regeneration. Then, we review iPSC to Schwann cell derivation protocols and the results from recent in vitro and in vivo studies. We finally conclude with some prospects for the use of iPSCs in clinical settings.


2017 ◽  
Vol 33 (06) ◽  
pp. 435-440 ◽  
Author(s):  
Kai Yang ◽  
Yuhui Yan ◽  
Lin-Ling Zhang ◽  
Michael Agresti ◽  
Hani Matloub ◽  
...  

Background After peripheral nerve injury, there is an increase in calcium concentration in the injured nerves. Our previous publications have shown that increase in calcium concentration correlated well with degree of nerve injury and that local infusion of calcitonin has a beneficial effect on nerve recovery. Schwann cells play a pivotal role in regeneration and recovery. We aim to examine cultured Schwann cell survivals in various concentrations of calcium-containing growth media and the effect of calcitonin in such media. Methods To establish baseline in postinjury state, crush injury was induced in male Sprague-Dawley rats' sciatic nerves. Extra- and intraneural calcium concentrations were measured. To study Schwann cell survival, uninjured sciatic nerve segment was harvested and cultured in media containing various amounts of calcium. To study the effect of calcitonin, nerve harvest and culture were done in four additional media: (1) normal control, (2) normal control with calcitonin, (3) high calcium medium, and (4) high calcium medium with calcitonin. Schwann cells were studied and analyzed under fluorescent conditions. Results With increasing calcium concentration, there was a significant decrease in the number of Schwann cells. For the experimental groups, in which calcitonin had been added to the growth medium, there were similar amounts of Schwann cells present in both high and low calcium-containing medium. Conclusion Schwann cells are sensitive to increasing calcium concentration. Calcitonin counteracts the detrimental effects of high calcium on Schwann cell survival. This can have significant future clinical implications for patients with peripheral nerve injuries.


2005 ◽  
Vol 53 (8) ◽  
pp. 971-977 ◽  
Author(s):  
Brigitte Blondet ◽  
Gilles Carpentier ◽  
Fouad Lafdil ◽  
Jose Courty

Pleiotrophin (PTN) is a member of the family of heparin-binding growth factors that displays mitogenic activities and promotes neurite outgrowth in vitro. In vivo, PTN is widely expressed along pathways of developing axons during the late embryonic and early postnatal period. Although the level of PTN gene expression is very low during adulthood, activation of the gene may occur during recovery from injury and seems to play an important role in tissue regeneration processes. In this study, we investigated whether PTN was involved in the regenerative process of injured peripheral nerves. To refer localization of the fluorescent markers to myelinated axons, we developed a specific computer tool for colocalization of fluorescence images with phase contrast images. Immunohistochemical analysis showed PTN in different types of nonneural cells in distal nerve segments, including Schwann cells, macrophages, and endothelial cells, but not in axons. Schwann cells exhibited PTN immunoreactivity as early as 2 days after injury, whereas PTN-positive macrophages were found 1 week later. Strong PTN immunoreactivity was noted in endothelial cells at all time points. These findings support the idea that PTN participates in the adaptive response to peripheral nerve injury. A better understanding of its contribution may suggest new strategies for enhancing peripheral nerve regeneration.


2013 ◽  
Vol 119 (3) ◽  
pp. 720-732 ◽  
Author(s):  
Yerko A. Berrocal ◽  
Vania W. Almeida ◽  
Ranjan Gupta ◽  
Allan D. Levi

Object Segmental nerve defects pose a daunting clinical challenge, as peripheral nerve injury studies have established that there is a critical nerve gap length for which the distance cannot be successfully bridged with current techniques. Construction of a neural prosthesis filled with Schwann cells (SCs) could provide an alternative treatment to successfully repair these long segmental gaps in the peripheral nervous system. The object of this study was to evaluate the ability of autologous SCs to increase the length at which segmental nerve defects can be bridged using a collagen tube. Methods The authors studied the use of absorbable collagen conduits in combination with autologous SCs (200,000 cells/μl) to promote axonal growth across a critical size defect (13 mm) in the sciatic nerve of male Fischer rats. Control groups were treated with serum only–filled conduits of reversed sciatic nerve autografts. Animals were assessed for survival of the transplanted SCs as well as the quantity of myelinated axons in the proximal, middle, and distal portions of the channel. Results Schwann cell survival was confirmed at 4 and 16 weeks postsurgery by the presence of prelabeled green fluorescent protein–positive SCs within the regenerated cable. The addition of SCs to the nerve guide significantly enhanced the regeneration of myelinated axons from the nerve stump into the proximal (p < 0.001) and middle points (p < 0.01) of the tube at 4 weeks. The regeneration of myelinated axons at 16 weeks was significantly enhanced throughout the entire length of the nerve guide (p < 0.001) as compared with their number in a serum–only filled tube and was similar in number compared with the reversed autograft. Autotomy scores were significantly lower in the animals whose sciatic nerve was repaired with a collagen conduit either without (p < 0.01) or with SCs (p < 0.001) when compared with a reversed autograft. Conclusions The technique of adding SCs to a guidance channel significantly enhanced the gap distance that can be repaired after peripheral nerve injury with long segmental defects and holds promise in humans. Most importantly, this study represents some of the first essential steps in bringing autologous SC-based therapies to the domain of peripheral nerve injuries with long segmental defects.


2021 ◽  
Author(s):  
Songyang Liu ◽  
Liping Zhou ◽  
Ci Li ◽  
Tiantian Min ◽  
Changfeng Lu ◽  
...  

Abstract Peripheral nerve injury (PNI) is one of the common clinical injuries which needs to be addressed. Previous studies demonstrated the effectiveness of using biodegradable chitin (CT) conduits small gap tubulization technology as a substitute for traditional epineurial neurorrhaphy. Aiming to improve the effectiveness of CT conduits in repairing PNI, we modified their surface with a DNA-peptide coating. The coating consisted of single strand DNA (ssDNA) and its complementary DNA’-peptide mimics. First, we immobilize ssDNA (DNA1+2) on CT conduits by EDC/NHS method to construct CT/DNA conduits. EDC/NHS was used to activate carboxyl groups of modified ssDNA for direct reaction with primary amines on the chitin via amide bond formation. Then, DNA1’-BDNF+DNA2’-VEGF mimic peptide (RGI+KLT)were bonded to CT/DNA conduits by complementary base pairing principle at room temperature to form CT/RGI+KLT conduits. When the surrounding environment rose to a certain point (37℃), the CT/RGI+KLT conduits achieved sustainable release of DNA’-peptide. In vitro, the CT conduits modified with the DNA-peptide coating promoted the proliferation and secretion of Schwann cells by maintaining their repair state. It also promoted the proliferation of HUVECs and axon outgrowth of DRG explants. In vivo, CT/RGI+KLT conduits promoted regeneration of injured nerves and functional recovery of target muscles, which was facilitated by the synergistic contribution of angiogenesis and neurogenesis. Our research brings DNA and DNA-peptide hybrids into the realm of tissue engineering to repair peripheral nerve injury.


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