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Trolle C, Han Y, Mutt SJ, Christoffersson G, Kozlova EN. Boundary cap neural crest stem cells promote angiogenesis after transplantation to avulsed dorsal roots in mice and induce migration of endothelial cells in 3D printed scaffolds. Neurosci Lett 2024; 826:137724. [PMID: 38467271 DOI: 10.1016/j.neulet.2024.137724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Revised: 02/26/2024] [Accepted: 03/08/2024] [Indexed: 03/13/2024]
Abstract
Dorsal root avulsion injuries lead to loss of sensation and to reorganization of blood vessels (BVs) in the injured area. The inability of injured sensory axons to re-enter the spinal cord results in permanent loss of sensation, and often also leads to the development of neuropathic pain. Approaches that restore connection between peripheral sensory axons and their CNS targets are thus urgently need. Previous research has shown that sensory axons from peripherally grafted human sensory neurons are able to enter the spinal cord by growing along BVs which penetrate the CNS from the spinal cord surface. In this study we analysed the distribution of BVs after avulsion injury and how their pattern is affected by implantation at the injury site of boundary cap neural crest stem cells (bNCSCs), a transient cluster of cells, which are located at the boundary between the spinal cord and peripheral nervous system and assist the growth of sensory axons from periphery into the spinal cord during development. The superficial dorsal spinal cord vasculature was examined using intravital microscopy and intravascular BV labelling. bNCSC transplantation increased vascular volume in a non-dose responsive manner, whereas dorsal root avulsion alone did not decrease the vascular volume. To determine whether bNCSC are endowed with angiogenic properties we prepared 3D printed scaffolds, containing bNCSCs together with rings prepared from mouse aorta. We show that bNCSC do induce migration and assembly of endothelial cells in this system. These findings suggest that bNCSC transplant can promote vascularization in vivo and contribute to BV formation in 3D printed scaffolds.
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Zhou X, Tang A, Xiong C, Zhang G, Huang L, Xu F. Oriented Graphene Oxide Scaffold Promotes Nerve Regeneration in vitro and in vivo. Int J Nanomedicine 2024; 19:2573-2589. [PMID: 38505172 PMCID: PMC10949378 DOI: 10.2147/ijn.s439656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 02/14/2024] [Indexed: 03/21/2024] Open
Abstract
Background Treating peripheral nerve injuries (PNI) with defects remains challenging in clinical practice. The commercial conduits have shown suboptimal nerve regeneration and functional recovery due to their basic tubular design without electroactive and oriented topographical cues. Purpose To develop a new scaffold with oriented microstructure and electroactive Graphene oxide (GO) and investigate its' therapeutic effect on nerve regeneration in vitro and in vivo. Methods This study employed a straightforward approach to co-spin PCL and GO, yielding an oriented hybrid nanofibrous scaffold known as the O-GO/PCL scaffold. The physical and chemical properties of nanofibrous scaffold were tested by scanning electron microscopy (SEM), transmission electron microscope (TEM), tensile test and so on. Primary Schwann cells (SCs) and dorsal root ganglia (DRG) were used to investigate the impact of the newly developed scaffolds on the biological behavior of neural cells in vitro. Transcriptome sequencing (mRNA-seq) was employed to probe the underlying mechanisms of the synergistic effect of electroactive GO and longitudinal topographic guidance on nerve regeneration. Furthermore, the developed O-GO/PCL scaffold was utilized to bridge a 10-mm sciatic nerve defect in rat, aiming to investigate its therapeutic potential for peripheral nerve regeneration in vivo. Results and discussion The SEM and TEM revealed that the newly developed O-GO/PCL scaffold showed longitudinally oriented microstructure and GO particles were homogenously and uniformly distributed inside the nanofibers. Primary SCs were utilized to assess the biocompatibility of the GO-based scaffold, revealing that negligible cytotoxicity when GO concentration does not exceed 0.5%. In vitro analysis of nerve regeneration demonstrated that axons in the O-GO/PCL group exhibited an average length of 1054.88 ± 161.32 µm, significant longer than those in the other groups (P < 0.05). Moreover, mRNA sequencing results suggested that the O-GO/PCL scaffold could enhance nerve regeneration by upregulating genes associated with neural regeneration, encompassing ion transport, axon guidance and cell-cell interactions. Most importantly, we employed the O-GO/PCL scaffold to repair a 10-mm sciatic nerve defect in rat, resulting in augmented nerve regeneration, myelination, and functional recovery. Conclusion The O-GO/PCL scaffold with oriented microstructure and electroactive GO represents a promising heral nerve reconstruction.
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Zhang N, Ji Q, Chen Y, Wen X, Shan F. TREM2 deficiency impairs the energy metabolism of Schwann cells and exacerbates peripheral neurological deficits. Cell Death Dis 2024; 15:193. [PMID: 38453910 PMCID: PMC10920707 DOI: 10.1038/s41419-024-06579-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 02/26/2024] [Accepted: 02/28/2024] [Indexed: 03/09/2024]
Abstract
Triggering receptor expressed on myeloid cells-2 (TREM2) has been implicated in susceptibility to neurodegenerative disease. Schwann cells (SCs), the predominant glial cell type in the peripheral nervous system (PNS), play a crucial role in myelination, providing trophic support for neurons and nerve regeneration. However, the function of TREM2 in SCs has not been fully elucidated. Here, we found that TREM2 is expressed in SCs but not in neurons in the PNS. TREM2 deficiency leads to disruption of glycolytic flux and oxidative metabolism in SCs, impairing cell proliferation. The energy crisis caused by TREM2 deficiency triggers mitochondrial damage and autophagy by activating AMPK and impairing PI3K-AKT-mTOR signaling. Combined metabolomic analysis demonstrated that energic substrates and energy metabolic pathways were significantly impaired in TREM2-deficient SCs. Moreover, TREM2 deficiency impairs energy metabolism and axonal growth in sciatic nerve, accompanied by exacerbation of neurological deficits and suppression of nerve regeneration in a mouse model of acute motor axonal neuropathy. These results indicate that TREM2 is a critical regulator of energy metabolism in SCs and exerts neuroprotective effects on peripheral neuropathy. TREM2 deficiency impairs glycolysis and oxidative metabolism in Schwann cells, resulting in compromised cell proliferation. The energy crisis caused by TREM2 deficiency induces mitochondrial damage and autophagy by activating AMPK and impairing PI3K-AKT-mTOR signaling. Moreover, TREM2 deficiency disrupts the energy metabolism of the sciatic nerve and impairs support for axonal regeneration, accompanied by exacerbation of neurological deficits and suppression of nerve regeneration in a mouse model of acute motor axonal neuropathy (by FigDraw).
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Huang C, Zheng Y, Ji R, Qiao L, Zhang X, Lin H, Liu F, Xu J, Li Y, Zhang Z, Yang X. GPNMB promotes peripheral nerve regeneration by activating the Erk1/2 and Akt pathways via binding Na +/K +-ATPase α1 in Schwann cells. Exp Neurol 2024; 373:114687. [PMID: 38199512 DOI: 10.1016/j.expneurol.2024.114687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 12/24/2023] [Accepted: 01/06/2024] [Indexed: 01/12/2024]
Abstract
Glycoprotein non-metastatic melanoma protein B (GPNMB) is ubiquitously expressed and has protective effects on the central nervous system. In particular, it is also expressed in the peripheral nervous system (PNS) and upregulated after peripheral nerve injury. However, the role and underlying mechanism of GPNMB in the PNS, especially in peripheral nerve regeneration (PNR), are still unknown and need to be further investigated. In this study, recombinant human GPNMB (rhGPNMB) was injected into a sciatic nerve injury model. It was found that rhGPNMB facilitated the regeneration and functional recovery of the injured sciatic nerve in vivo. Moreover, it was also confirmed that GPNMB activated the Erk1/2 and Akt pathways via binding with Na+/K + -ATPase α1 (NKA α1) and promoted the proliferation and migration of Schwann cells (SCs) and their expression and secretion of neurotrophic factors and neural adhesion molecules in vitro. Our findings demonstrate that GPNMB facilitates PNR through activation of the Erk1/2 and Akt pathways in SCs by binding with NKA α1 and may be a novel strategy for PNR.
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Xia X, Shi C, Tsien C, Sun CB, Xie L, Luo Z, Bian M, Russano K, Thakur HS, Benowitz LI, Goldberg JL, Kapiloff MS. Ca 2+/Calmodulin-Dependent Protein Kinase II Enhances Retinal Ganglion Cell Survival But Suppresses Axon Regeneration after Optic Nerve Injury. eNeuro 2024; 11:ENEURO.0478-23.2024. [PMID: 38548335 PMCID: PMC10978821 DOI: 10.1523/eneuro.0478-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 03/01/2024] [Accepted: 03/05/2024] [Indexed: 04/01/2024] Open
Abstract
Neuroprotection after injury or in neurodegenerative disease remains a major goal for basic and translational neuroscience. Retinal ganglion cells (RGCs), the projection neurons of the eye, degenerate in optic neuropathies after axon injury, and there are no clinical therapies to prevent their loss or restore their connectivity to targets in the brain. Here we demonstrate a profound neuroprotective effect of the exogenous expression of various Ca2+/calmodulin-dependent protein kinase II (CaMKII) isoforms in mice. A dramatic increase in RGC survival following the optic nerve trauma was elicited by the expression of constitutively active variants of multiple CaMKII isoforms in RGCs using adeno-associated viral (AAV) vectors across a 100-fold range of AAV dosing in vivo. Despite this neuroprotection, however, short-distance RGC axon sprouting was suppressed by CaMKII, and long-distance axon regeneration elicited by several pro-axon growth treatments was likewise inhibited even as CaMKII further enhanced RGC survival. Notably, in a dose-escalation study, AAV-expressed CaMKII was more potent for axon growth suppression than the promotion of survival. That diffuse overexpression of constitutively active CaMKII strongly promotes RGC survival after axon injury may be clinically valuable for neuroprotection per se. However, the associated strong suppression of the optic nerve axon regeneration demonstrates the need for understanding the intracellular domain- and target-specific CaMKII activities to the development of CaMKII signaling pathway-directed strategies for the treatment of optic neuropathies.
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Tereshenko V, Dotzauer DC, Schmoll M, Harnoncourt L, Carrero Rojas G, Gfrerer L, Eberlin KR, Austen WG, Blumer R, Farina D, Aszmann OC. Peripheral neural interfaces: Skeletal muscles are hyper-reinnervated according to the axonal capacity of the surgically rewired nerves. SCIENCE ADVANCES 2024; 10:eadj3872. [PMID: 38416828 PMCID: PMC10901366 DOI: 10.1126/sciadv.adj3872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Accepted: 01/23/2024] [Indexed: 03/01/2024]
Abstract
Advances in robotics have outpaced the capabilities of man-machine interfaces to decipher and transfer neural information to and from prosthetic devices. We emulated clinical scenarios where high- (facial) or low-neural capacity (ulnar) donor nerves were surgically rewired to the sternomastoid muscle, which is controlled by a very small number of motor axons. Using retrograde tracing and electrophysiological assessments, we observed a nearly 15-fold functional hyper-reinnervation of the muscle after high-capacity nerve transfer, demonstrating its capability of generating a multifold of neuromuscular junctions. Moreover, the surgically redirected axons influenced the muscle's physiological characteristics, by altering the expression of myosin heavy-chain types in alignment with the donor nerve. These findings highlight the remarkable capacity of skeletal muscles to act as biological amplifiers of neural information from the spinal cord for governing bionic prostheses, with the potential of expressing high-dimensional neural function for high-information transfer interfaces.
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Rademakers DJ, Saffari S, Saffari TM, Pulos N, Shin AY. The Effect of Local Purified Exosome Product, Stem Cells, and Tacrolimus on Neurite Extension. J Hand Surg Am 2024; 49:237-246. [PMID: 38165293 DOI: 10.1016/j.jhsa.2023.11.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 01/03/2024]
Abstract
PURPOSE The combination of cellular and noncellular treatments has been postulated to improve nerve regeneration through a processed nerve allograft. This study aimed to evaluate the isolated effect of treatment with purified exosome product (PEP), mesenchymal stem cells (MSCs), and tacrolimus (FK506) alone and in combination when applied in decellularized allografts. METHODS A three-dimensional in vitro-compartmented cell culture system was used to evaluate the length of regenerating neurites from the neonatal dorsal root ganglion into the adjacent peripheral nerve graft. Decellularized nerve allografts were treated with undifferentiated MSCs, 5% PEP, 100 ng/mL FK506, PEP and FK506 combined, or MSCs and FK506 combined (N = 9/group) and compared with untreated nerve autografts (positive control) and nerve allografts (negative control). Neurite extension was measured to quantify nerve regeneration after 48 hours, and stem cell viability was evaluated. RESULTS Stem cell viability was confirmed in all MSC-treated nerve grafts. Treatments with PEP, PEP + FK506, and MSCs + FK506 combined were found to be superior to untreated allografts and not significantly different from autografts. Combined PEP and FK506 treatment resulted in the greatest neurite extension. Treatment with FK506 and MSCs was significantly superior to MSC alone. The combined treatment groups were not found to be statistically different. CONCLUSIONS Although all treatments improved neurite outgrowth, treatments with PEP, PEP + FK506, and MSCs + FK506 combined had superior neurite growth compared with untreated allografts and were not found to be significantly different from autografts, the current gold standard. CLINICAL RELEVANCE Purified exosome product, a cell-free exosome product, is a promising adjunct to enhance nerve allograft regeneration, with possible future avenues for clinical translation.
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Stadlmayr S, Peter K, Millesi F, Rad A, Wolf S, Mero S, Zehl M, Mentler A, Gusenbauer C, Konnerth J, Schniepp HC, Lichtenegger H, Naghilou A, Radtke C. Comparative Analysis of Various Spider Silks in Regard to Nerve Regeneration: Material Properties and Schwann Cell Response. Adv Healthc Mater 2024; 13:e2302968. [PMID: 38079208 DOI: 10.1002/adhm.202302968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/20/2023] [Indexed: 12/26/2023]
Abstract
Peripheral nerve reconstruction through the employment of nerve guidance conduits with Trichonephila dragline silk as a luminal filling has emerged as an outstanding preclinical alternative to avoid nerve autografts. Yet, it remains unknown whether the outcome is similar for silk fibers harvested from other spider species. This study compares the regenerative potential of dragline silk from two orb-weaving spiders, Trichonephila inaurata and Nuctenea umbratica, as well as the silk of the jumping spider Phidippus regius. Proliferation, migration, and transcriptomic state of Schwann cells seeded on these silks are investigated. In addition, fiber morphology, primary protein structure, and mechanical properties are studied. The results demonstrate that the increased velocity of Schwann cells on Phidippus regius fibers can be primarily attributed to the interplay between the silk's primary protein structure and its mechanical properties. Furthermore, the capacity of silk fibers to trigger cells toward a gene expression profile of a myelinating Schwann cell phenotype is shown. The findings for the first time allow an in-depth comparison of the specific cellular response to various native spider silks and a correlation with the fibers' material properties. This knowledge is essential to open up possibilities for targeted manufacturing of synthetic nervous tissue replacement.
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Wang L, Zhang S, Han Y, Tang S, Li J, Bu L, Zhao D, Deng H. An effective pharmacological hydrogel induces optic nerve repair and improves visual function. SCIENCE CHINA. LIFE SCIENCES 2024; 67:529-542. [PMID: 38041780 DOI: 10.1007/s11427-023-2394-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 05/09/2023] [Indexed: 12/03/2023]
Abstract
Irreversible eye lesions, such as glaucoma and traumatic optic neuropathy, can cause blindness; however, no effective treatments exist. The optic nerve, in particular, lacks the capacity to spontaneously regenerate, requiring the development of an effective approach for optic nerve repair, which has proven challenging. Here, we demonstrate that a combination of the small molecules 3BDO and trichostatin A (TSA)-which regulate mTOR and HDAC, respectively-packaged in thermosensitive hydrogel for 4-week-sustained release after intravitreal injection, effectively induced optic nerve regeneration in a mouse model of optic nerve crush injury. Moreover, this combination of 3BDO and TSA also protected axon projections and improved visual responses in an old mouse model (11 months old) of glaucoma. Taken together, our data provide a new, local small molecule-based treatment for the effective induction of optic nerve repair, which may represent a foundation for the development of pharmacological methods to treat irreversible eye diseases.
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Bhattacharya SK, Alabiad CR, Kishor K. Appropriate patient population for future visual system axon regeneration therapies. WIREs Mech Dis 2024; 16:e1637. [PMID: 38093604 PMCID: PMC10939871 DOI: 10.1002/wsbm.1637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 11/07/2023] [Accepted: 11/20/2023] [Indexed: 03/16/2024]
Abstract
A number of blinding diseases caused by damage to the optic nerve result in progressive vision loss or loss of visual acuity. Secondary glaucoma results from traumatic injuries, pseudoexfoliation or pigmentary dispersion syndrome. Progressive peripheral vision loss is common to all secondary glaucoma irrespective of the initial event. Axon regeneration is a potential therapeutic avenue to restore lost vision in these patients. In contrast to the usual approach of having the worst possible patient population for initial therapies, axon regeneration may require consideration of appropriate patient population even for initial treatment trials. The current state of axon regeneration therapies, their potential future and suitable patient population when ready is discussed in this perspective. The selection of patients are important for adoption of axon regeneration specifically in the areas of central nervous system regenerative medicine. This article is categorized under: Neurological Diseases > Molecular and Cellular Physiology Neurological Diseases > Biomedical Engineering Metabolic Diseases > Molecular and Cellular Physiology.
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Duan Q, Zheng H, Qin Y, Yan J, Wang J, Burgess SM, Fan C. Stat3 Has a Different Role in Axon Growth During Development Than It Does in Axon Regeneration After Injury. Mol Neurobiol 2024; 61:1753-1768. [PMID: 37775721 DOI: 10.1007/s12035-023-03644-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 09/07/2023] [Indexed: 10/01/2023]
Abstract
Signal transducer and activator of transcription 3 (STAT3) is essential for neural development and regeneration as a key transcription factor and mitochondrial activator. However, the mechanism of Stat3 in axon development and regeneration has not been fully understood. In this study, using zebrafish posterior lateral line (PLL) axons, we demonstrate that Stat3 plays distinct roles in PLL axon embryonic growth and regeneration. Our experiments indicate that stat3 is required for PLL axon extension. In stat3 mutant zebrafish, the PLL axon ends were stalled at the level of the cloaca, and expression of stat3 rescues the PLL axon growth in a cell-autonomous manner. Jak/Stat signaling inhibition did not affect PLL axon growth indicating Jak/Stat was dispensable for PLL axon growth. In addition, we found that Stat3 was co-localized with mitochondria in PLL axons and important for the mitochondrial membrane potential and ATPase activity. The PLL axon growth defect of stat3 mutants was mimicked and rescued by rotenone and DCHC treatment, respectively, which suggests that Stat3 regulates PLL axon growth through mitochondrial Stat3. By contrast, mutation of stat3 or Jak/Stat signaling inhibition retarded PLL axon regeneration. Meanwhile, we also found Schwann cell migration was also inhibited in stat3 mutants. Taken together, Stat3 is required for embryonic PLL axon growth by regulating the ATP synthesis efficiency of mitochondria, whereas Stat3 stimulates PLL axon regeneration by regulating Schwann cell migration via Jak/Stat signaling. Our findings show a new mechanism of Stat3 in axon growth and regeneration.
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Li J, Lu JE, Bokman CL, Chang JR. Other Neurogenic Ptosis: Aberrant Facial Nerve Regeneration. J Neuroophthalmol 2024; 44:e143-e144. [PMID: 36000761 DOI: 10.1097/wno.0000000000001706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Iwahashi T, Suzuki K, Tanaka H, Matsuoka H, Nishimoto S, Hirai Y, Kasuya T, Shimada T, Yoshimura Y, Oka K, Murase T, Okada S. Neurotropin® accelerates peripheral nerve regeneration in a rat sciatic nerve crush injury model. J Orthop Sci 2024; 29:653-659. [PMID: 36858838 DOI: 10.1016/j.jos.2023.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 02/05/2023] [Accepted: 02/06/2023] [Indexed: 03/03/2023]
Abstract
BACKGROUND Peripheral nerve injuries are common and serious conditions. The effect of Neurotropin® (NTP), a nonprotein extract derived from the inflamed skin of rabbits inoculated with vaccinia virus, on peripheral nerve regeneration has not been fully elucidated. However, it has analgesic properties via the activation of descending pain inhibitory systems. Therefore, the current study aimed to determine the effects of NTP on peripheral nerve regeneration. METHODS We examined axonal outgrowth of dorsal root ganglion (DRG) neurons using immunocytochemistry in vitro. In addition, nerve regeneration was evaluated functionally, electrophysiologically, and histologically in a rat sciatic nerve crush injury model in vivo. Furthermore, gene expression of neurotrophic factors in the injured sciatic nerves and DRGs was evaluated. RESULTS In the dorsal root ganglion neurons in vitro, NTP promoted axonal outgrowth at a concentration of 10 mNU/mL. Moreover, the systemic administration of NTP contributed to the recovery of motor and sensory function at 2 weeks, and of sensory function, nerve conduction velocity, terminal latency, and axon-remyelination 4 weeks after sciatic nerve injury. In the gene expression assessment, insulin-like growth factor 1 and vascular endothelial growth factor expressions were increased in the injured sciatic nerve 2 days postoperatively. CONCLUSIONS Therefore, NTP might be effective in not only treating chronic pain but also promoting peripheral nerve regeneration after injury.
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Franklin RJM, Bodini B, Goldman SA. Remyelination in the Central Nervous System. Cold Spring Harb Perspect Biol 2024; 16:a041371. [PMID: 38316552 PMCID: PMC10910446 DOI: 10.1101/cshperspect.a041371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
The inability of the mammalian central nervous system (CNS) to undergo spontaneous regeneration has long been regarded as a central tenet of neurobiology. However, while this is largely true of the neuronal elements of the adult mammalian CNS, save for discrete populations of granule neurons, the same is not true of its glial elements. In particular, the loss of oligodendrocytes, which results in demyelination, triggers a spontaneous and often highly efficient regenerative response, remyelination, in which new oligodendrocytes are generated and myelin sheaths are restored to denuded axons. Yet remyelination in humans is not without limitation, and a variety of demyelinating conditions are associated with sustained and disabling myelin loss. In this work, we will (1) review the biology of remyelination, including the cells and signals involved; (2) describe when remyelination occurs and when and why it fails, including the consequences of its failure; and (3) discuss approaches for therapeutically enhancing remyelination in demyelinating diseases of both children and adults, both by stimulating endogenous oligodendrocyte progenitor cells and by transplanting these cells into demyelinated brain.
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Wang X, Hu S, Ouyang S, Pan X, Fu Y, Chen X, Wu S. TsMS combined with EA promotes functional recovery and axonal regeneration via mediating the miR-539-5p/Sema3A/PlexinA1 signalling axis in sciatic nerve-injured rats. Neurosci Lett 2024; 824:137691. [PMID: 38373630 DOI: 10.1016/j.neulet.2024.137691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 02/10/2024] [Accepted: 02/16/2024] [Indexed: 02/21/2024]
Abstract
Enhancing axonal regeneration is one of the most important processes in treating nerve injuries. Both magnetic and electrical stimulation have the effect of promoting nerve axon regeneration. But few study has investigated the effects of trans-spinal magnetic stimulation (TsMS) combined with electroacupuncture (EA) on nerve regeneration in rats with sciatic nerve injury. In this study, we compared the improvement of neurological function in rats with sciatic nerve crush injuries after 4 weeks of different interventions (EA, TsMS, or TsMS combined with EA). We further explored the morphological and molecular biological alterations following sciatic nerve injury by HE, Masson, RT-PCR, western blotting, immunofluorescence staining and small RNA transcriptome sequencing. The results showed that TsMS combined with EA treatment significantly promoted axonal regeneration, increased the survival rate of neurons, and suppressed denervation atrophy of the gastrocnemius muscle. Subsequent experiments suggested that the combination treatment may play an active role by mediating the miR-539-5p/Sema3A/PlexinA1 signaling axis.
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Wang J, Chen P, Han G, Zhou Y, Xiang X, Bian M, Huang L, Wang X, He B, Lu S. Rab32 facilitates Schwann cell pyroptosis in rats following peripheral nerve injury by elevating ROS levels. J Transl Med 2024; 22:194. [PMID: 38388913 PMCID: PMC10885539 DOI: 10.1186/s12967-024-04999-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Accepted: 02/13/2024] [Indexed: 02/24/2024] Open
Abstract
BACKGROUND Peripheral nerve injury (PNI) is commonly observed in clinical practice, yet the underlying mechanisms remain unclear. This study investigated the correlation between the expression of a Ras-related protein Rab32 and pyroptosis in rats following PNI, and potential mechanisms have been explored by which Rab32 may influence Schwann cells pyroptosis and ultimately peripheral nerve regeneration (PNR) through the regulation of Reactive oxygen species (ROS) levels. METHODS The authors investigated the induction of Schwann cell pyroptosis and the elevated expression of Rab32 in a rat model of PNI. In vitro experiments revealed an upregulation of Rab32 during Schwann cell pyroptosis. Furthermore, the effect of Rab32 on the level of ROS in mitochondria in pyroptosis model has also been studied. Finally, the effects of knocking down the Rab32 gene on PNR were assessed, morphology, sensory and motor functions of sciatic nerves, electrophysiology and immunohistochemical analysis were conducted to assess the therapeutic efficacy. RESULTS Silencing Rab32 attenuated PNI-induced Schwann cell pyroptosis and promoted peripheral nerve regeneration. Furthermore, our findings demonstrated that Rab32 induces significant oxidative stress by damaging the mitochondria of Schwann cells in the pyroptosis model in vitro. CONCLUSION Rab32 exacerbated Schwann cell pyroptosis in PNI model, leading to delayed peripheral nerve regeneration. Rab32 can be a potential target for future therapeutic strategy in the treatment of peripheral nerve injuries.
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Shlapakova LE, Botvin VV, Mukhortova YR, Zharkova II, Alipkina SI, Zeltzer A, Dudun AA, Makhina T, Bonartseva GA, Voinova VV, Wagner DV, Pariy I, Bonartsev AP, Surmenev RA, Surmeneva MA. Magnetoactive Composite Conduits Based on Poly(3-hydroxybutyrate) and Magnetite Nanoparticles for Repair of Peripheral Nerve Injury. ACS APPLIED BIO MATERIALS 2024; 7:1095-1114. [PMID: 38270084 DOI: 10.1021/acsabm.3c01032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2024]
Abstract
Peripheral nerve injury poses a threat to the mobility and sensitivity of a nerve, thereby leading to permanent function loss due to the low regenerative capacity of mature neurons. To date, the most widely clinically applied approach to bridging nerve injuries is autologous nerve grafting, which faces challenges such as donor site morbidity, donor shortages, and the necessity of a second surgery. An effective therapeutic strategy is urgently needed worldwide to overcome the current limitations. Herein, a magnetic nerve guidance conduit (NGC) based on biocompatible biodegradable poly(3-hydroxybutyrate) (PHB) and 8 wt % of magnetite nanoparticles modified by citric acid (Fe3O4-CA) was fabricated by electrospinning. The crystalline structure of NGCs was studied by X-ray diffraction, which indicated an enlarged β-phase of PHB in the composite conduit compared to a pure PHB conduit. Tensile tests revealed greater ductility of PHB/Fe3O4-CA: the composite conduit has Young's modulus of 221 ± 52 MPa and an elongation at break of 28.6 ± 2.9%, comparable to clinical materials. Saturation magnetization (σs) of Fe3O4-CA and PHB/Fe3O4-CA is 61.88 ± 0.29 and 7.44 ± 0.07 emu/g, respectively. The water contact angle of the PHB/Fe3O4-CA conduit is lower as compared to pure PHB, while surface free energy (σ) is significantly higher, which was attributed to higher surface roughness and an amorphous phase as well as possible PHB/Fe3O4-CA interface interactions. In vitro, the conduits supported the proliferation of rat mesenchymal stem cells (rMSCs) and SH-SY5Y cells in a low-frequency magnetic field (0.67 Hz, 68 mT). In vivo, the conduits were used to bridge damaged sciatic nerves in rats; pure PHB and composite PHB/Fe3O4-CA conduits did not cause acute inflammation and performed a barrier function, which promotes nerve regeneration. Thus, these conduits are promising as implants for the regeneration of peripheral nerves.
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Yao L, Xu W, Liu L, Xu X, Xi H, Xue B, Cao X, Lin S, Piao G, Sun J, Wang X. The involvement of Neuregulin-1 in the process of facial nerve injury repair through the utilization of dental pulp stem cells. BMC Oral Health 2024; 24:238. [PMID: 38355448 PMCID: PMC10868091 DOI: 10.1186/s12903-024-03953-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 01/29/2024] [Indexed: 02/16/2024] Open
Abstract
BACKGROUND Facial nerve injury often results in poor prognosis due to the challenging process of nerve regeneration. Neuregulin-1, a human calmodulin, is under investigation in this study for its impact on the reparative capabilities of Dental Pulp Stem Cells (DPSCs) in facial nerve injury. METHODS Lentivirus was used to transfect and construct Neuregulin-1 overexpressed DPSCs. Various techniques assessed the effects of Neuregulin-1: osteogenic induction, lipid induction, Reverse Transcription Polymerase Chain Reaction, Western Blot, Cell Counting Kit-8 assay, wound healing, immunofluorescence, Phalloidin staining, nerve stem action potential, Hematoxylin-eosin staining, transmission electron microscopy, and immunohistochemistry. RESULTS Neuregulin-1 effectively enhanced the proliferation, migration, and cytoskeletal rearrangement of DPSCs, while simultaneously suppressing the expression of Ras homolog gene family member A (RhoA) and Microfilament actin (F-actin). These changes facilitated the neural differentiation of DPSCs. Additionally, in vivo experiments showed that Neuregulin-1 expedited the restoration of action potential in the facial nerve trunk, increased the thickness of the myelin sheath, and stimulated axon regeneration. CONCLUSION Neuregulin-1 has the capability to facilitate the repair of facial nerve injuries by promoting the regenerative capacity of DPSCs. Thus, Neuregulin-1 is a significant potential gene in the reparative processes of nerve damage.
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Yi W, Xue Y, Qing W, Cao Y, Zhou L, Xu M, Sun Z, Li Y, Mai X, Shi L, He C, Zhang F, Duh EJ, Cao Y, Liu X. Effective treatment of optic neuropathies by intraocular delivery of MSC-sEVs through augmenting the G-CSF-macrophage pathway. Proc Natl Acad Sci U S A 2024; 121:e2305947121. [PMID: 38289952 PMCID: PMC10861878 DOI: 10.1073/pnas.2305947121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 12/21/2023] [Indexed: 02/01/2024] Open
Abstract
Optic neuropathies, characterized by injury of retinal ganglion cell (RGC) axons of the optic nerve, cause incurable blindness worldwide. Mesenchymal stem cell-derived small extracellular vesicles (MSC-sEVs) represent a promising "cell-free" therapy for regenerative medicine; however, the therapeutic effect on neural restoration fluctuates, and the underlying mechanism is poorly understood. Here, we illustrated that intraocular administration of MSC-sEVs promoted both RGC survival and axon regeneration in an optic nerve crush mouse model. Mechanistically, MSC-sEVs primarily targeted retinal mural cells to release high levels of colony-stimulating factor 3 (G-CSF) that recruited a neural restorative population of Ly6Clow monocytes/monocyte-derived macrophages (Mo/MΦ). Intravitreal administration of G-CSF, a clinically proven agent for treating neutropenia, or donor Ly6Clow Mo/MΦ markedly improved neurological outcomes in vivo. Together, our data define a unique mechanism of MSC-sEV-induced G-CSF-to-Ly6Clow Mo/MΦ signaling in repairing optic nerve injury and highlight local delivery of MSC-sEVs, G-CSF, and Ly6Clow Mo/MΦ as therapeutic paradigms for the treatment of optic neuropathies.
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Wang Y, Yang B, Huang Z, Yang Z, Wang J, Ao Q, Yin G, Li Y. Progress and mechanism of graphene oxide-composited materials in application of peripheral nerve repair. Colloids Surf B Biointerfaces 2024; 234:113672. [PMID: 38071946 DOI: 10.1016/j.colsurfb.2023.113672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 11/21/2023] [Accepted: 11/23/2023] [Indexed: 02/09/2024]
Abstract
Peripheral nerve injuries (PNI) are one of the most common nerve injuries, and graphene oxide (GO) has demonstrated significant potential in the treatment of PNI. GO could enhance the proliferation, adhesion, migration, and differentiation of neuronal cells by upregulating the expression of relevant proteins, and regulate the angiogenesis process and immune response. Therefore, GO is a suitable additional component for fabricating artificial nerve scaffolds (ANS), in which the slight addition of GO could improve the physicochemical performance of the matrix materials, through hydrogen bonds and electrostatic attraction. GO-composited ANS can increase the expression of nerve regeneration-associated genes and factors, promoting angiogenesis by activating the RAS/MAPK and AKT-eNOS-VEGF signaling pathway, respectively. Moreover, GO could be metabolized and excreted from the body through the pathway of peroxidase degradation in vivo. Consequently, the application of GO in PNI regeneration exhibits significant potential for transitioning from laboratory research to clinical use.
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Bazan HEP, Pham TL. A new R,R-RvD6 isomer with protective actions following corneal nerve injury. Prostaglandins Other Lipid Mediat 2024; 170:106802. [PMID: 38036037 DOI: 10.1016/j.prostaglandins.2023.106802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 11/05/2023] [Accepted: 11/27/2023] [Indexed: 12/02/2023]
Abstract
The transparent cornea is the most densely innervated tissue in the body, primarily by sensory nerves originating from the trigeminal ganglia (TG). Damage to corneal nerves reduces sensitivity and tear secretion and results in dry eye. Consequently, ocular pain, for which no satisfactory therapies exist, arises in many cases. Treatment of injured corneas with pigment epithelium-derived factor (PEDF) combined with docosahexaenoic acid (DHA) stimulates nerve regeneration in models of refractive surgery, which damages nerves. The mechanism involves the synthesis of a stereoisomer of resolvin D6 (R,R-RvD6) formed after incorporating DHA into membrane lipids. Activation of a PEDF receptor (PEDF-R) with phospholipase activity releases DHA to synthesize the new resolvin isomer, which is secreted via tears. Topical treatment of mice corneas with R,R-RvD6 shows higher bioactivity in regenerating nerves and increasing sensitivity compared to PEDF+DHA. It also stimulates a transcriptome in the TG that modulates genes involved in ocular pain. Our studies suggest an important therapeutic role for R,R-RvD6 in regenerating corneal nerves and decreasing pain resulting from dry eye.
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Lee J, Nguyen S, Bhattacharya S. Optic nerve regeneration: Potential treatment approaches. Curr Opin Pharmacol 2024; 74:102428. [PMID: 38171063 PMCID: PMC10922496 DOI: 10.1016/j.coph.2023.102428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 12/13/2023] [Accepted: 12/14/2023] [Indexed: 01/05/2024]
Abstract
The optic nerve, predominantly constituted by the axons of retinal ganglion cells (RGCs), lacks the ability to regenerate and re-establish function after injury. RGCs are crucial for visual function, and thus, RGC death contributes to the development of numerous progressive neurodegenerative optic neuropathies including glaucoma, ischemic optic neuropathy, and optic neuritis. Regenerating optic nerve axons poses numerous challenges due to factors such as the intricate and inhibitory conditions that exist within their environment, intrinsic breaks to regeneration, and the geometric tortuosity that offers physical hindrance to axon growth. However, recent research advancements offer hope for clinically meaningful regeneration for those who suffer from optic nerve damage. In this review, we highlight the current treatment approaches for optic nerve axon regeneration.
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Glaser JJ, Aman M, Böcker AH, Thielen M, Harhaus L. [Nerve Transfers in Peripheral Nerve Lesions]. HANDCHIR MIKROCHIR P 2024; 56:49-54. [PMID: 38316412 DOI: 10.1055/a-2228-7062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024] Open
Abstract
BACKGROUND Lesions of peripheral nerves of the upper extremities often lead to persistent, serious limitations in motor function and sensory perception. Affected patients suffer from both private and professional restrictions associated with long-term physical, psychological and socioeconomic consequences. INDICATION An early indication for a nerve transfer shortens the reinnervation distance and improves the growing of motor and sensory axons into the target organ to facilitate early mobility and sensitivity. When planning the timepoint of the surgical procedure, the distance to be covered by reinnervation as well as the morbidities of donor nerves must be considered individually. RESULTS Nerve transfers can achieve earlier and safer reinnervation to improve motor and sensory functions after nerve injuries in the upper extremity.
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Bertelli JA, Rosa ICN, Ghizoni MF. Retrograde peripheral nerve regeneration from sensory to motor pathways in rats: a new experimental concept in nerve repair. Neurol Res 2024; 46:125-131. [PMID: 37729085 DOI: 10.1080/01616412.2023.2258039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 09/03/2023] [Indexed: 09/22/2023]
Abstract
BACKGROUND The polarity of nerve grafts does not interfere with axon growth. Our goal was to investigate whether axons can regenerate in a retrograde fashion within sensory pathways and then extend into motor pathways, leading to muscle reinnervation. METHODS Fifty-four rats were randomized into four groups. In Group 1, the ulnar nerve was connected end-to-end to the superficial radial nerve after neurectomy of the radial nerve in the axilla. In Group 2, the ulnar nerve was connected end-to-end to the radial nerve distal to the humerus; the radial nerve then was divided in the axilla. In Group 3, the radial nerve was divided in the axilla, but no nerve reconstruction was performed. In Group 4, the radial nerve was crushed in the axilla. Over 6 months, we behaviorally assessed the recovery of toe spread in the right operated-upon forepaw by lifting the rat by its tail and lowering it onto a flat surface. Six months after surgery, rats underwent reoperation, nerve transfers were tested electrophysiologically, and the posterior interosseous nerve (PIN) was removed for histological evaluation. RESULTS Rats in the crush group recovered toe spread between 5 and 8 days after surgery. Rats with nerve transfers demonstrated electrophysiological and histological findings of nerve regeneration but no behavioral recovery. CONCLUSIONS Ulnar nerve axons regrew into the superficial radial nerve and then into the PIN to reinnervate the extensor digitorum communis. We were unable to demonstrate behavioral recovery because rats cannot readapt to cross-nerve transfer.
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Jiang X, Wang W, Tang J, Han M, Xu Y, Zhang L, Wu J, Huang Y, Ding Z, Sun H, Xi K, Gu Y, Chen L. Ligand-Screened Cerium-Based MOF Microcapsules Promote Nerve Regeneration via Mitochondrial Energy Supply. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2306780. [PMID: 38037294 PMCID: PMC10853750 DOI: 10.1002/advs.202306780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 10/28/2023] [Indexed: 12/02/2023]
Abstract
Although mitochondria are crucial for recovery after spinal cord injury (SCI), therapeutic strategies to modulate mitochondrial metabolic energy to coordinate the immune response and nerve regeneration are lacking. Here, a ligand-screened cerium-based metal-organic framework (MOF) with better ROS scavenging and drug-loading abilities is encapsulated with polydopamine after loading creatine to obtain microcapsules (Cr/Ce@PDA nanoparticles), which reverse the energy deficits in both macrophages and neuronal cells by combining ROS scavenging and energy supplementation. It reprogrames inflammatory macrophages to the proregenerative phenotype via the succinate/HIF-1α/IL-1β signaling axis. It also promotes the regeneration and differentiation of neural cells by activating the mTOR pathway and paracrine function of macrophages. In vivo experiments further confirm the effect of the microcapsules in regulating early ROS-inflammation positive-feedback chain reactions and continuously promoting nerve regeneration. This study provides a new strategy for correcting mitochondrial energy deficiency in the immune response and nerve regeneration following SCI.
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