Involvement of acidic fibroblast growth factor in spinal cord injury repair processes revealed by a proteomics approach

Cellular and Transcriptional Response of Human Astrocytes to Hybrid Protein Materials

Collagen is a major component of the tissue matrix, and soybean can regulate the tissue immune response. Both materials have been used to fabricate biomaterials for tissue repair. In this study, adult and fetal human astrocytes were grown in a soy protein isolate (SPI)-collagen hybrid gel or on the surface of a cross-linked SPI-collagen membrane. Hybrid materials reduced the cell proliferation rate compared to materials generated by collagen alone. However, the hybrid materials did not significantly change the cell motility compared to the control collagen material. RNA-sequencing (RNA-Seq) analysis showed downregulated genes in the cell cycle pathway, including CCNA2, CCNB1, CCNB2, CCND1, CCND2, and CDK1, which may explain lower cell proliferation in the hybrid material. This study also revealed the downregulation of genes encoding extracellular matrix (ECM) components, including HSPG2, LUM, SDC2, COL4A1, COL4A5, COL4A6, and FN1, as well as genes encoding chemokines, including CCL2, CXCL1, CXCL2, CX3CL1, CXCL3, and LIF, for adult human astrocytes grown on the hybrid membrane compared with those grown on the control collagen membrane. The study explored the cellular and transcriptional responses of human astrocytes to the hybrid material and indicated a potential beneficial function of the material in the application of neural repair.

Molecular Mechanisms in the Vascular and Nervous Systems following Traumatic Spinal Cord Injury

Traumatic spinal cord injury (SCI) induces various complex pathological processes that cause physical impairment and psychological devastation. The two phases of SCI are primary mechanical damage (the immediate result of trauma) and secondary injury (which occurs over a period of minutes to weeks). After the mechanical impact, vascular disruption, inflammation, demyelination, neuronal cell death, and glial scar formation occur during the acute phase. This sequence of events impedes nerve regeneration. In the nervous system, various extracellular secretory factors such as neurotrophic factors, growth factors, and cytokines are involved in these events. In the vascular system, the blood-spinal cord barrier (BSCB) is damaged, allowing immune cells to infiltrate the parenchyma. Later, endogenous angiogenesis is promoted during the subacute phase. In this review, we describe the roles of secretory factors in the nervous and vascular systems following traumatic SCI, and discuss the outcomes of their therapeutic application in traumatic SCI.

Bibliometric analysis of research on gene expression in spinal cord injury

Background

Spinal cord injury (SCI) is a severe disease with motor and sensory function being destroyed, which leads to a poor prognosis and a serious financial burden. It is urgent to figure out the molecular and pathological mechanisms of SCI to develop feasible therapeutic strategies. This article aims to review documents focused on gene expression in SCI and summarize research hotspots and the development process in this field.

Methods

Publications of SCI-related studies from 2000 to 2022 were retrieved from the Web of Science Core Collection database. Biblioshiny was used to evaluate the research performance, core authors, journals and contributed countries, together with trend topics, hotspots in the field, and keyword co-occurrence analysis. Visualized images were obtained to help comprehension.

Results

Among 351 documents, it was found that the number of annual publications increased in general. The most productive country was China, followed by the United States with the highest influence and the most international cooperation. Plos One was the journal of the maximum publications, while Journal of Neuroscience was the most influential one. According to keyword co-occurrence and trend topics analysis, these articles mainly focused on molecular and pathological mechanisms as well as novel therapies for SCI. Neuropathic pain, axonal regeneration and messenger RNA are significant and promising research areas.

Conclusion

As the first bibliometric study focused on gene expression in SCI, we demonstrated the evolution of the field and provided future research directions like mechanisms and treatments of SCI with great innovativeness and clinical value. Further studies are recommended to develop more viable therapeutic methods for SCI.

The Application of an Omentum Graft or Flap in Spinal Cord Injury

Background: Spinal cord injury (SCI) causes a primary injury at the lesion site and triggers a secondary injury and prolonged inflammation. There has been no definitive treatment till now. Promoting angiogenesis is one of the most important strategies for functional recovery after SCI. The omentum, abundant in blood and lymph vessels, possesses the potent ability of tissue regeneration. Methods: The present work examines the efficacy of autologous omentum, either as a flap (with vascular connection intact) or graft (severed vascular connection), on spinal nerve regeneration. After contusive SCI in rats, a thin sheath of omentum was grafted to the injured spinal cord. Results: Omental graft improved behavior scores significantly from the 3rd to 6th week after injury (6th week, 5.5 ± 0.5 vs. 8.6 ± 1.3, p < 0.05). Furthermore, the reduction in cavity and the preservation of class III β-tubulin-positive nerve fibers in the injury area was noted. Next, the free omental flap was transposed to a completely transected SCI in rats through a pre-implanted tunnel. The flap remained vascularized and survived well several weeks after the operation. At 16 weeks post-treatment, SCI rats with omentum flap treatment displayed the preservation of significantly more nerve fibers (p < 0.05) and a reduced injured cavity, though locomotor scores were similar. Conclusions: Taken together, the findings of this study indicate that treatment with an omental graft or transposition of an omental flap on an injured spinal cord has a positive effect on nerve protection and tissue preservation in SCI rats. The current data highlight the importance of omentum in clinical applications.

Multimodal treatment combining cold atmospheric plasma and acidic fibroblast growth factor for multi-tissue regeneration

Cold atmospheric plasma (CAP) is an emerging technology for biomedical applications, exemplified by its antimicrobial and antineoplastic potentials. On the contrary, acidic fibroblast growth factor (aFGF) has been a long-standing potent mitogen for cells from various origins. In this study, we are the first to develop a multimodal treatment combining the aforementioned physicochemical and pharmacological treatments and investigated their individual and combined effects on wound healing, angiogenesis, neurogenesis, and osteogenesis. This work was performed at the tissue, cellular, protein, and gene levels, using histochemical staining, flow cytometry, ELISA, and PCR, respectively. Depending on the type of target tissue, various combinations of aforementioned methods were used. The results showed that the enhancement on would healing and angiogenesis by CAP and aFGF were synergistic. The former was manifested by increased murine fibroblast proliferation and reduced cutaneous tissue inflammation, whereas the latter by upregulated proangiogenic markers in vivo, for example, CD31, VEGF, and TGF-β, and downregulated antiangiogenic proteins in vitro, for example, angiostatin and angiopoietin-2, respectively. In addition, aFGF outperformed CAP during neurogenesis, which was evidenced by superior neurite outgrowth, while CAP exceeded aFGF in osteogenesis which was demonstrated by more substantial bone nodule formation. These novel findings not only support the fact that CAP and aFGF are both multipotent agents during tissue regeneration, but also highlight the potential of our multimodal treatment combining the individual advantages of CAP and aFGF. The versatile administration route, that is, topical and/or systemic, might further broaden its applications.

Reduction in post-spinal cord injury spasticity by combination of peripheral nerve grafting and acidic fibroblast growth factor infusion in monkeys

OBJECTIVE

Spasticity is a frequent complication after spinal cord injury (SCI), but the existing therapies provide only limited relief and are associated with adverse reactions. Therefore, we aimed to develop a novel strategy to ameliorate the spasticity induced by SCI.

METHODS

This nonrandomized controlled study used a repeated measurement design. The study involved four monkeys, two of which served as controls and only underwent spinal cord hemisection surgery at the T8 spine level. The other two monkeys underwent transplantation of sural nerve segments into the injured sites and long-term infusion of acidic fibroblast growth factor (aFGF). All monkeys received postoperative exercise training and therapy.

RESULTS

The combined therapy substantially reduced the spasticity in leg muscle tone, patella tendon reflex, and fanning of toes. Although all monkeys showed spontaneous recovery of function over time, the recovery in the controls reached a plateau and started to decline after 11 weeks.

CONCLUSIONS

The combination of peripheral nerve grafting and aFGF infusion may serve as a complementary approach to reduce the signs of spasticity in patients with SCI.

Silencing of Long Noncoding RNA Growth Arrest-Specific 5 Alleviates Neuronal Cell Apoptosis and Inflammatory Responses Through Sponging microRNA-93 to Repress PTEN Expression in Spinal Cord Injury

A secondary injury induced by a spinal cord injury (SCI) remains the main cause of devastating neural dysfunction; therefore, it has been the subject of focused research for many years. Long noncoding RNA (lncRNA) has been found to participate in the SCI process, and this finding presents a high potential for diagnosis and treatment; however, the role of lncRNA in a secondary injury induced by SCI remains unclear. The aim of this study was to investigate the regulatory effect of lncRNA growth arrest–specific transcript 5 (GAS5) in secondary injury during SCI. The SCI mice model and hypoxic cellular model were established to research the roles of lncRNA GAS5 during SCI. Reverse transcription quantitative polymerase chain reaction (qRT-PCR) was conducted to determine the expression levels of microR-93 (miR-93) and lncRNA GAS5. Western blot analysis of the apoptosis regulator protein and terminal deoxynucleotidyl transferase dUTP nick end labeling assay was conducted to evaluate neuron cell apoptosis. Basso, Beattie, and Bresnahan (BBB) scores were calculated to assess neurological function. Flow cytometry was used to determine neuron cell apoptosis. The associations among GAS5, miR-93, and the phosphatase and tensin homolog (PTEN) were disclosed using RNA immunoprecipitation (RIP) assay, RNA pulldown assay, and dual-luciferase reporter assay. QRT-PCR demonstrated that GAS5 was significantly upregulated in both the SCI mice and hypoxic cellular models. GAS5 knockdown suppressed neuron cell apoptosis and inflammatory response in the SCI mice model. Further studies have indicated that GAS5 functions as a competing endogenous RNA (ceRNA) by sponging miR-93 in neuronal cells. In addition, PTEN was a target of miR-93, and GAS5 knockdown exhibited its anti-apoptotic and anti-inflammatory effects through the miR-93/PTEN axis. These findings suggest that the GAS5/miR-93/PTEN axis may be a promising therapeutic target for SCI.

Fibroblast Growth Factor Signalling in the Diseased Nervous System

Fibroblast growth factors (FGFs) act as key signalling molecules in brain development, maintenance, and repair. They influence the intricate relationship between myelinating cells and axons as well as the association of astrocytic and microglial processes with neuronal perikarya and synapses. Advances in molecular genetics and imaging techniques have allowed novel insights into FGF signalling in recent years. Conditional mouse mutants have revealed the functional significance of neuronal and glial FGF receptors, not only in tissue protection, axon regeneration, and glial proliferation but also in instant behavioural changes. This review provides a summary of recent findings regarding the role of FGFs and their receptors in the nervous system and in the pathogenesis of major neurological and psychiatric disorders.

Zebra-Fishing for Regenerative Awakening in Mammals

Regeneration is defined as the ability to regrow an organ or a tissue destroyed by degeneration or injury. Many human degenerative diseases and pathologies, currently incurable, could be cured if functional tissues or cells could be restored. Unfortunately, humans and more generally mammals have limited regenerative capabilities, capacities that are even further declining with age, contrary to simpler organisms. Initially thought to be lost during evolution, several studies have revealed that regenerative mechanisms are still present in mammals but are latent and thus they could be stimulated. To do so there is a pressing need to identify the fundamental mechanisms of regeneration in species able to efficiently regenerate. Thanks to its ability to regenerate most of its organs and tissues, the zebrafish has become a powerful model organism in regenerative biology and has recently engendered a number of studies attesting the validity of awakening the regenerative potential in mammals. In this review we highlight studies, particularly in the liver, pancreas, retina, heart, brain and spinal cord, which have identified conserved regenerative molecular events that proved to be beneficial to restore murine and even human cells and which helped clarify the real clinical translation potential of zebrafish research to mammals.

Glial Metabolic Rewiring Promotes Axon Regeneration and Functional Recovery in the Central Nervous System

Axons in the mature central nervous system (CNS) fail to regenerate after axotomy, partly due to the inhibitory environment constituted by reactive glial cells producing astrocytic scars, chondroitin sulfate proteoglycans, and myelin debris. We investigated this inhibitory milieu, showing that it is reversible and depends on glial metabolic status. We show that glia can be reprogrammed to promote morphological and functional regeneration after CNS injury in Drosophila via increased glycolysis. This enhancement is mediated by the glia derived metabolites: L-lactate and L-2-hydroxyglutarate (L-2HG). Genetically/pharmacologically increasing or reducing their bioactivity promoted or impeded CNS axon regeneration. L-lactate and L-2HG from glia acted on neuronal metabotropic GABA_B receptors to boost cAMP signaling. Local application of L-lactate to injured spinal cord promoted corticospinal tract axon regeneration, leading to behavioral recovery in adult mice. Our findings revealed a metabolic switch to circumvent the inhibition of glia while amplifying their beneficial effects for treating CNS injuries.

The superiority of conditioned medium derived from rapidly expanded mesenchymal stem cells for neural repair

Background

Spinal cord injury (SCI) is a complex and severe neurological condition. Mesenchymal stem cells (MSCs) and their secreted factors show promising potential for regenerative medicine. Many studies have investigated MSC expansion efficacy of all kinds of culture medium formulations, such as growth factor-supplemented or xeno-free medium. However, very few studies have focused on the potential of human MSC (hMSC) culture medium formulations for injured spinal cord repair. In this study, we investigated the effect of hMSC-conditioned medium supplemented with bFGF, EGF, and patient plasma, namely, neural regeneration laboratory medium (NRLM), on SCI in vitro and in vivo.

Methods

Commercial and patient bone marrow hMSCs were obtained for cultivation in standard medium and NRLM separately. Several characteristics, including CD marker expression, differentiation, and growth curves, were compared between MSCs cultured in standard medium and NRLM. Additionally, we investigated the effect of the conditioned medium (referred to as NRLM-CM) on neural repair, including inflammation inhibition, neurite regeneration, and spinal cord injury (SCI), and used a coculture system to detect the neural repair function of NRLM-MSCs.

Results

Compared to standard culture medium, NRLM-CM had superior in inflammation reduction and neurite regeneration effects in vitro and improved functional restoration in SCI rats in vivo. In comparison with standard culture medium MSCs, NRLM-MSCs proliferated faster regardless of the age of the donor. NRLM-MSCs also showed increased adipose differentiative potential and reduced CD90 expression. Both types of hMSC CM effectively enhanced injured neurite outgrowth and protected against H₂O₂ toxicity in spinal cord neuron cultures. Cytokine arrays performed in hMSC-CM further revealed the presence of at least 120 proteins. Among these proteins, 6 demonstrated significantly increased expression in NRLM-CM: adiponectin (Acrp30), angiogenin (ANG), HGF, NAP-2, uPAR, and IGFBP2.

Conclusions

The NRLM culture system provides rapid expansion effects and functional hMSCs. The superiority of the derived conditioned medium on neural repair shows potential for future clinical applications.

Phosphatidylethanolamine-Binding Protein 1 Ameliorates Ischemia-Induced Inflammation and Neuronal Damage in the Rabbit Spinal Cord

In a previous study, we utilized a proteomic approach and found a significant reduction in phosphatidylethanolamine-binding protein 1 (PEBP1) protein level in the spinal cord at 3 h after ischemia. In the present study, we investigated the role of PEBP1 against oxidative stress in NSC34 cells in vitro, and ischemic damage in the rabbit spinal cord in vivo. We generated a PEP-1-PEBP1 fusion protein to facilitate the penetration of blood-brain barrier and intracellular delivery of PEBP1 protein. Treatment with PEP-1-PEBP1 significantly decreased cell death and the induction of oxidative stress in NSC34 cells. Furthermore, administering PEP-1-PEBP1 did not show any significant side effects immediately before and after ischemia/reperfusion. Administration of PEP-PEBP1 improved the Tarlov’s neurological score at 24 and 72 h after ischemia, and significantly improved neuronal survival at 72 h after ischemia based on neuronal nuclei (NeuN) immunohistochemistry, Flouro-Jade B staining, and western blot study for cleaved caspase 3. PEP-1-PEBP1 administration decreased oxidative stress based on malondialdehyde level, advanced oxidation protein products, and 8-iso-prostaglandin F2α in the spinal cord. In addition, inflammation based on myeloperoxidase level, tumor necrosis factor-α level, and high mobility group box 1 level was decreased by PEP-1-PEBP1 treatment at 72 h after ischemia. Thus, PEP-1-PEBP1 treatment, which decreases oxidative stress, inflammatory cytokines, and neuronal death, may be an effective therapeutic strategy for spinal cord ischemia.

Monkey Recovery from Spinal Cord Hemisection: Nerve Repair Strategies for Rhesus Macaques

OBJECTIVE

Repair of spinal cord injury (SCI) using peripheral nerve graft (PNG) and acidic fibroblast growth factor (aFGF) has shown promising results in rats and a few human patients, but not in nonhuman primates. The aim of this study was to verify the effective use of PNG and aFGF for repairing incomplete SCI in nonhuman primates.

METHODS

Six adult rhesus macaques received spinal cord hemisection at T8 level and were grouped into repair and control groups (n = 3 in each). Animals in the repair group underwent nerve repair with autologous PNG plus aFGF immediately after lesioning. The control group received exactly the same operation for lesioning but no treatment. Postoperative behavioral evaluations, electrophysiologic tests (including motor and somatosensory evoked potentials), and magnetic resonance imaging were performed and compared between the 2 groups as well as histologic examination of the spinal cord cephalic to, at, and caudal to the lesion site after sacrifice.

RESULTS

Animals in the repair group had better motor function in the lower limbs at every observed time point and demonstrated more improvement on electrophysiologic examinations than the control group. The repair group had smaller areas of myelomalacia on magnetic resonance imaging around the lesion compared with the control group, suggesting diminished inflammatory responses with the repair strategy.

CONCLUSIONS

PNG plus aFGF for SCI in nonhuman primates yielded improvements in clinical behavior, electrophysiologic tests, and magnetic resonance imaging. This study suggests that the repair strategy is feasible and effective for nonhuman primate SCI. Further investigations are warranted to corroborate its effectiveness for clinical application.

Glucocorticoids Target Ependymal Glia and Inhibit Repair of the Injured Spinal Cord

Following injury, the mammalian spinal cord forms a glial scar and fails to regenerate. In contrast, vertebrate fish spinal cord tissue regenerates significantly to restore function. Cord transection in zebrafish (Danio rerio) initially causes paralysis and neural cell death. Subsequently, ependymal glia proliferate, bipolar glia extend across the lesion, and new neurons are born; axons from spared and nascent neurons extend along trans-lesional glial bridges to restore functional connectivity. Here we report that glucocorticoids, used in the clinical management of spinal cord injury, directly inhibit neural repair by targeting ependymal glia independently of hematogenous cells and microglia. After transecting injury, the glucocorticoid receptor in ependymal glia is regulated differentially in zebrafish (becoming inactive) vs. the rat (becoming active). Glucocorticoid blockade of neural regeneration via a direct effect on ependymal glia has important therapeutic implications for the putative benefit of corticosteroids in early management of spinal cord injury.

Acidic Fibroblast Growth Factor in Spinal Cord Injury

Spinal cord injury (SCI), with an incidence rate of 246 per million person-years among adults in Taiwan, remains a devastating disease in the modern day. Elderly men with lower socioeconomic status have an even higher risk for SCI. Despite advances made in medicine and technology to date, there are few effective treatments for SCI due to limitations in the regenerative capacity of the adult central nervous system. Experiments and clinical trials have explored neuro-regeneration in human SCI, encompassing cell- and molecule-based therapies. Furthermore, strategies have aimed at restoring connections, including autologous peripheral nerve grafts and biomaterial scaffolds that theoretically promote axonal growth. Most molecule-based therapies target the modulation of inhibitory molecules to promote axonal growth, degrade glial scarring obstacles, and stimulate intrinsic regenerative capacity. Among them, acidic fibroblast growth factor (aFGF) has been investigated for nerve repair; it is mitogenic and pluripotent in nature and could enhance axonal growth and mitigate glial scarring. For more than 2 decades, the authors have conducted multiple trials, including human and animal experiments, using aFGF to repair nerve injuries, including central and peripheral nerves. In these trials, aFGF has shown promise for neural regeneration, and in the future, more trials and applications should investigate aFGF as a neurotrophic factor. Focusing on aFGF, the current review aimed to summarize the historical evolution of the utilization of aFGF in SCI and nerve injuries, to present applications and trials, to summarize briefly its possible mechanisms, and to provide future perspectives.

Different Fgfs have distinct roles in regulating neurogenesis after spinal cord injury in zebrafish

Background

Despite conserved developmental processes and organization of the vertebrate central nervous system, only some vertebrates including zebrafish can efficiently regenerate neural damage including after spinal cord injury. The mammalian spinal cord shows very limited regeneration and neurogenesis, resulting in permanent life-long functional impairment. Therefore, there is an urgent need to identify the cellular and molecular mechanisms that can drive efficient vertebrate neurogenesis following injury. A key pathway implicated in zebrafish neurogenesis is fibroblast growth factor signaling.

Methods

In the present study we investigated the roles of distinct fibroblast growth factor members and their receptors in facilitating different aspects of neural development and regeneration at different timepoints following spinal cord injury. After spinal cord injury in adults and during larval development, loss and/or gain of Fgf signaling was combined with immunohistochemistry, in situ hybridization and transgenes marking motor neuron populations in in vivo zebrafish and in vitro mammalian PC12 cell culture models.

Results

Fgf3 drives neurogenesis of Islet1 expressing motor neuron subtypes and mediate axonogenesis in cMet expressing motor neuron subtypes. We also demonstrate that the role of Fgf members are not necessarily simple recapitulating development. During development Fgf2, Fgf3 and Fgf8 mediate neurogenesis of Islet1 expressing neurons and neuronal sprouting of both, Islet1 and cMet expressing motor neurons. Strikingly in mammalian PC12 cells, all three Fgfs increased cell proliferation, however, only Fgf2 and to some extent Fgf8, but not Fgf3 facilitated neurite outgrowth.

Conclusions

This study demonstrates differential Fgf member roles during neural development and adult regeneration, including in driving neural proliferation and neurite outgrowth of distinct spinal cord neuron populations, suggesting that factors including Fgf type, age of the organism, timing of expression, requirements for different neuronal populations could be tailored to best drive all of the required regenerative processes.

Extracellular Neuroleukin Enhances Neuroleukin Secretion From Astrocytes and Promotes Axonal Growth in vitro and in vivo

Under pathological conditions in the central nervous system (CNS), including spinal cord injury, astrocytes show detrimental effects against neurons. It is also known that astrocytes sometimes exert beneficial effects, such as neuroprotection and secretion of axonal growth factors. If beneficial effects of astrocytes after injury could be induced, dysfunction of the injured CNS may improve. However, a way of promoting beneficial functions in astrocytes has not been elucidated. In the current study, we focused on neuroleukin (NLK), which is known to have axonal growth activities in neurons. Although NLK is secreted from astrocytes, the function of NLK in astrocytes is poorly understood. We aimed to clarify the mechanism of NLK secretion in astrocytes and the functional significance of secreted NLK from astrocytes. Stimulation of cultured astrocytes with recombinant NLK significantly elevated the secretion of NLK from astrocytes. Furthermore, astrocyte conditioned medium treated with NLK increased axonal density in cultured cortical neurons. Recombinant NLK itself directly increased axonal density in cultured neurons. These results indicated that NLK secreted from astrocytes acted as an axonal growth factor and that secretion was stimulated by extracellular NLK. To elucidate a direct binding molecule of NLK on astrocytes, drug affinity responsive target stability (DARTS) analysis was performed. A 78 kDa glucose regulated protein (GRP78) was identified as a receptor for NLK, which was related to the secretion of NLK from astrocytes. When NLK was injected into the lesion site of spinal cord injured mice, axonal density in the injured region was significantly increased and hindlimb motor function improved. These results suggested that NLK-GRP78 signalling was important for the beneficial effects of astrocytes. This study strengthens the potential of astrocytes for use as therapeutic targets in CNS traumatic injury.

Spinal cord self-repair during tail regeneration in Polypedates maculatus and putative role of FGF1 as a neurotrophic factor

Spinal cord injury could be fatal in man and often results in irreversible medical conditions affecting mobility. However, anuran amphibians win over such pathological condition by the virtue of regeneration abilities. The tail of anuran tadpoles therefore allures researchers to study spinal cord injury and self- repair process. In the present study, we inflicted injury to the spinal cord by means of surgical transection of the tail and investigated the self-repair activity in the tadpoles of the Indian tree frog Polypedates maculatus. We also demonstrate for the first time by immunofluorescence localization the expression pattern of Fibroblast Growth Factor1 (FGF1) during spinal cord regeneration which has not been documented earlier in anurans. FGF1, bearer of the mitogenic and neurotrophic properties seems to be expressed by progenitor cells that facilitate regeneration. Spinal cord during tail regeneration in P. maculatus attains functional recovery within a span of 2 weeks thus enabling the organism to survive in an aquatic medium till metamorphosis. Moreover, during the course of spinal cord regeneration in the regenerating tail, melanocytes showed an interesting behaviour as these neural crest derivatives were missing near the early regenerates until their reappearance where they were positioned in close proximity with the regenerated spinal cord as in the normal tail.

Fibroblast growth factors in the management of spinal cord injury

Spinal cord injury (SCI) possesses a significant health and economic burden worldwide. Traumatic SCI is a devastating condition that evolves through two successive stages. Throughout each of these stages, disturbances in ionic homeostasis, local oedema, ischaemia, focal haemorrhage, free radicals stress and inflammatory response were observed. Although there are no fully restorative cures available for SCI patients, various molecular, cellular and rehabilitative therapies, such as limiting local inflammation, preventing secondary cell death and enhancing the plasticity of local circuits in the spinal cord, were described. Current preclinical studies have showed that fibroblast growth factors (FGFs) alone or combination therapies utilizing cell transplantation and biomaterial scaffolds are proven effective for treating SCI in animal models. More importantly, some studies further demonstrated a paucity of clinical transfer usage to promote functional recovery of numerous patients with SCI. In this review, we focus on the therapeutic capacity and pitfalls of the FGF family and its clinical application for treating SCI, including the signalling component of the FGF pathway and the role in the central nervous system, the pathophysiology of SCI and the targets for FGF treatment. We also discuss the challenges and potential for the clinical translation of FGF-based approaches into treatments for SCI.

Post-spinal cord injury astrocyte-mediated functional recovery in rats after intraspinal injection of the recombinant adenoviral vectors Ad5-VEGF and Ad5-ANG

OBJECTIVE The most actively explored therapeutic strategy for overcoming spinal cord injury (SCI) is the delivery of genes encoding molecules that stimulate regeneration. In a mouse model of amyotrophic lateral sclerosis and in preliminary clinical trials in patients with amyotrophic lateral sclerosis, the combined administration of recombinant adenoviral vectors (Ad5-VEGF+Ad5-ANG) encoding the neurotrophic/angiogenic factors vascular endothelial growth factor ( VEGF) and angiogenin ( ANG) was found to slow the development of neurological deficits. These results suggest that there may be positive effects of this combination of genes in posttraumatic spinal cord regeneration. The objective of the present study was to determine the effects of Ad5-VEGF+Ad5-ANG combination therapy on motor function recovery and reactivity of astrocytes in a rat model of SCI. METHODS Spinal cord injury was induced in adult Wistar rats by the weight-drop method. Rats (n = 51) were divided into 2 groups: the experimental group (Ad5-VEGF+Ad5-ANG) and the control group (Ad5-GFP [green fluorescent protein]). Recovery of motor function was assessed using the Basso, Beattie, and Bresnahan scale. The duration and intensity of infectivity and gene expression from the injected vectors were assessed by immunofluorescent detection of GFP. Reactivity of glial cells was assessed by changes in the number of immunopositive cells expressing glial fibrillary acidic protein (GFAP), S100β, aquaporin 4 (AQP4), oligodendrocyte transcription factor 2, and chondroitin sulfate proteoglycan 4. The level of S100β mRNA expression in the spinal cord was estimated by real-time polymerase chain reaction. RESULTS Partial recovery of motor function was observed 30 days after surgery in both groups. However, Basso, Beattie, and Bresnahan scores were 35.9% higher in the Ad5-VEGF+Ad5-ANG group compared with the control group. Specific GFP signal was observed at distances of up to 5 mm in the rostral and caudal directions from the points of injection. A 1.5 to 2.0-fold increase in the number of GFAP⁺, S100β⁺, and AQP4⁺ cells was observed in the white and gray matter at a distance of up to 5 mm from the center of the lesion site in the caudal and rostral directions. At 30 days after injury, a 2-fold increase in S100β transcripts was observed in the Ad5-VEGF+Ad5-ANG group compared with the control group. CONCLUSIONS Intraspinal injection of recombinant adenoviral vectors encoding VEGF and ANG stimulates functional recovery after traumatic SCI. The increased number of S100β⁺ astrocytes induced by this approach may be a beneficial factor for maintaining the survival and function of neurons. Therefore, gene therapy with Ad5-VEGF+Ad5-ANG vectors is an effective therapeutic method for SCI treatment.

Transgenic human embryonic stem cells overexpressing FGF2 stimulate neuroprotection following spinal cord ventral root avulsion

Ventral root avulsion (VRA) triggers a strong glial reaction which contributes to neuronal loss, as well as to synaptic detachment. To overcome the degenerative effects of VRA, treatments with neurotrophic factors and stem cells have been proposed. Thus, we investigated neuroprotection elicited by human embryonic stem cells (hESC), modified to overexpress a human fibroblast growth factor 2 (FGF-2), on motoneurons subjected to VRA. Lewis rats were submitted to VRA (L4-L6) and hESC/FGF-2 were applied to the injury site using a fibrin scaffold. The spinal cords were processed to evaluate neuronal survival, synaptic stability, and glial reactivity two weeks post lesion. Then, qRT-PCR was used to assess gene expression of β2-microglobulin (β2m), TNFα, IL1β, IL6 and IL10 in the spinal cord in vivo and FGF2 mRNA levels in hESC in vitro. The results indicate that hESC overexpressing FGF2 significantly rescued avulsed motoneurons, preserving synaptic covering and reducing astroglial reactivity. The cells were also shown to express BDNF and GDNF at the site of injury. Additionally, engraftment of hESC led to a significant reduction in mRNA levels of TNFα at the spinal cord ventral horn, indicating their immunomodulatory properties. Overall, the present data suggest that hESC overexpressing FGF2 are neuroprotective and can shift gene expression towards an anti-inflammatory environment.

Neurotrophic Factors Used to Treat Spinal Cord Injury

The application of neurotrophic factors as a therapy to improve morphological and behavioral outcomes after experimental spinal cord injury (SCI) has been the focus of many studies. These studies vary markedly in the type of neurotrophic factor that is delivered, the mode of administration, and the location, timing, and duration of the treatment. Generally, the majority of studies have had significant success if neurotrophic factors are applied in or close to the lesion site during the acute or the subacute phase after SCI. Comparatively fewer studies have administered neurotrophic factors in order to directly target the somata of injured neurons. The mode of delivery varies between acute injection of recombinant proteins, subacute or chronic delivery using a variety of strategies including osmotic minipumps, cell-mediated delivery, delivery using polymer release vehicles or supporting bridges of some sort, or the use of gene therapy to modify neurons, glial cells, or precursor/stem cells. In this brief review, we summarize the state of play of many of the therapies using these factors, most of which have been undertaken in rodent models of SCI.

Effects of Intraventricular Methotrexate on Neuronal Injury and Gene Expression in a Rat Model

Central nervous system (CNS)-directed treatment for acute lymphoblastic leukemia, used to prevent disease recurrence in the brain, is essential for survival. Systemic and intrathecal methotrexate, commonly used for CNS-directed treatment, have been associated with cognitive problems during and after treatment. The cortex, hippocampus, and caudate putamen, important brain regions for learning and memory, may be involved in methotrexate-induced brain injury. Objectives of this study were to (1) quantify neuronal degeneration in selected regions of the cortex, hippocampus, and caudate putamen and (2) measure changes in the expression of genes with known roles in oxidant defense, apoptosis/inflammation, and protection from injury. Male Sprague Dawley rats were administered 2 or 4 mg/kg of methotrexate diluted in artificial cerebrospinal fluid (aCSF) or aCSF only into the left cerebral lateral ventricle. Gene expression changes were measured using customized reverse transcription (RT)2 polymerase chain reaction arrays. The greatest percentage of degenerating neurons in methotrexate-treated animals was in the medial region of the cortex; percentage of degenerating neurons in the dentate gyrus and cornu ammonis 3 regions of the hippocampus was also greater in rats treated with methotrexate compared to perfusion and vehicle controls. There was a greater percentage of degenerating neurons in the inferior cortex of control versus methotrexate-treated animals. Eight genes involved in protection from injury, oxidant defense, and apoptosis/inflammation were significantly downregulated in different brain regions of methotrexate-treated rats. To our knowledge, this is the first study to investigate methotrexate-induced injury in selected brain regions and gene expression changes using a rat model of intraventricular drug administration.

Differential Neuroproteomic and Systems Biology Analysis of Spinal Cord Injury

Acute spinal cord injury (SCI) is a devastating condition with many consequences and no known effective treatment. Although it is quite easy to diagnose traumatic SCI, the assessment of injury severity and projection of disease progression or recovery are often challenging, as no consensus biomarkers have been clearly identified. Here rats were subjected to experimental moderate or severe thoracic SCI. At 24h and 7d postinjury, spinal cord segment caudal to injury center versus sham samples was harvested and subjected to differential proteomic analysis. Cationic/anionic-exchange chromatography, followed by 1D polyacrylamide gel electrophoresis, was used to reduce protein complexity. A reverse phase liquid chromatography-tandem mass spectrometry proteomic platform was then utilized to identify proteome changes associated with SCI. Twenty-two and 22 proteins were up-regulated at 24 h and 7 day after SCI, respectively; whereas 19 and 16 proteins are down-regulated at 24 h and 7 day after SCI, respectively, when compared with sham control. A subset of 12 proteins were identified as candidate SCI biomarkers - TF (Transferrin), FASN (Fatty acid synthase), NME1 (Nucleoside diphosphate kinase 1), STMN1 (Stathmin 1), EEF2 (Eukaryotic translation elongation factor 2), CTSD (Cathepsin D), ANXA1 (Annexin A1), ANXA2 (Annexin A2), PGM1 (Phosphoglucomutase 1), PEA15 (Phosphoprotein enriched in astrocytes 15), GOT2 (Glutamic-oxaloacetic transaminase 2), and TPI-1 (Triosephosphate isomerase 1), data are available via ProteomeXchange with identifier PXD003473. In addition, Transferrin, Cathepsin D, and TPI-1 and PEA15 were further verified in rat spinal cord tissue and/or CSF samples after SCI and in human CSF samples from moderate/severe SCI patients. Lastly, a systems biology approach was utilized to determine the critical biochemical pathways and interactome in the pathogenesis of SCI. Thus, SCI candidate biomarkers identified can be used to correlate with disease progression or to identify potential SCI therapeutic targets.

Clinical proteomics of enervated neurons

The dynamic field of neurosciences entails ever increasing search for molecular mechanisms of disease states, especially in the domain of neurodegenerative disorders. The previous century heralded the techniques in proteomics when indexing of the human proteomes relating to various disease conditions became important. Early stage research in certain diseases or pathological conditions requires a more holistic approach of first discovering the proteins of interest for the condition. Despite its limitations, proteomics is one of the most powerful techniques available to us today to dissect the molecular scenario in a particular disease situation. In this review we will discuss about the current clinical research in neurodegenerative disorders that employ proteomics techniques. We will specifically focus on our understanding of Alzheimer’s disease, traumatic spinal cord injury and neuromyelitis optica. Discussions will include ongoing worldwide research in these areas, research in India and specifically our laboratory in these domains of neurodegenerative conditions.

Molecular and Cellular Mechanisms of Axonal Regeneration After Spinal Cord Injury

Following axotomy, a complex temporal and spatial coordination of molecular events enables regeneration of the peripheral nerve. In contrast, multiple intrinsic and extrinsic factors contribute to the general failure of axonal regeneration in the central nervous system. In this review, we examine the current understanding of differences in protein expression and post-translational modifications, activation of signaling networks, and environmental cues that may underlie the divergent regenerative capacity of central and peripheral axons. We also highlight key experimental strategies to enhance axonal regeneration via modulation of intraneuronal signaling networks and the extracellular milieu. Finally, we explore potential applications of proteomics to fill gaps in the current understanding of molecular mechanisms underlying regeneration, and to provide insight into the development of more effective approaches to promote axonal regeneration following injury to the nervous system.

Acidic FGF promotes neurite outgrowth of cortical neurons and improves neuroprotective effect in a cerebral ischemic rat model

Acidic fibroblast growth factor (aFGF) is a neurotrophic factor which is a powerful neuroprotective and neuroregenerative factor of the nervous system. Prior study had shown that levels of FGFs significantly increase following ischemic injury, reflecting a physiological protection mechanism. However, few reports demonstrated the efficacy of applying aFGF in cerebral ischemia. A recent report showed that the intranasal aFGF treatment improved neurological functional recovery; however, it did not significantly reduce the lesion size in ischemic rats. The present study examines the neuroprotective effect of aFGF on cortical neuron-glial cultures under oxygen glucose deprivation (OGD)-induced cell damage and investigates whether epidural application of slow-released aFGF could improve benefit on ischemic stroke injury in conscious rats. We used a topical application of aFGF mixed in fibrin glue, a slow-release carrier, over the peri-ischemic cortex and examined such treatment on cerebral infarction and behavioral impairments of rats subjected to focal cerebral ischemia (FCI). Results demonstrate that aFGF effectively protected cortical neuron-glial cultures from OGD-induced neuronal damage. Neurite extension from cortical neurons was significantly enhanced by aFGF, mediated through activation of AKT and ERK. In addition, topical application of fibrin glue-mixed aFGF dose-dependently reduced ischemia-induced brain infarction and improved functional restoration in ischemic stroke rats. Slow-released aFGF not only protected hippocampal and cortical cell loss but reduced microglial infiltration in FCI rats. Our results suggest that aFGF mixed in fibrin glue could prolong the protective/regenerative efficacy of aFGF to the damaged brain tissue and thus improve the functional restorative effect of aFGF.

Recent proteomic advances in developmental, regeneration, and cancer governing signaling pathways

Embryonic development, adult tissue repair, and cancer share a number of common regulating pathways. The basic processes that govern the events that induce mesenchymal properties in epithelial cells-a process known as epithelial-mesenchymal transition-are central for embryonic development, and can be resumed in adults either during wound healing or tissue regeneration. A misregulation of these pathways is involved in pathological situations, such as tissue fibrosis and cancer. Proteomic approaches have emerged as promising tools to better understand the signaling pathways that govern these complex biological processes. This review focuses on the recent proteomic-based contributions to better understand the modulation of transforming growth factor-beta (TGF-β), wingless-type MMTV integration site family (Wnt), Notch and Receptor tyrosine kinase (RTK) signaling pathways. New advances include the description of new protein interactions, the formation of new protein complexes or the description on how some PTMs are regulating these pathways. Understanding protein interactions and the tempo-spatial modulation of these pathways might lead us to interesting research quests in cancer, embryonic development or even on improving adult tissue regeneration capabilities.

Neurotrophic factors for spinal cord repair: Which, where, how and when to apply, and for what period of time?

A variety of neurotrophic factors have been used in attempts to improve morphological and behavioural outcomes after experimental spinal cord injury (SCI). Here we review many of these factors, their cellular targets, and their therapeutic impact on spinal cord repair in different, primarily rodent, models of SCI. A majority of studies report favourable outcomes but results are by no means consistent, thus a major aim of this review is to consider how best to apply neurotrophic factors after SCI to optimize their therapeutic potential. In addition to which factors are chosen, many variables need be considered when delivering trophic support, including where and when to apply a given factor or factors, how such factors are administered, at what dose, and for how long. Overall, the majority of studies have applied neurotrophic support in or close to the spinal cord lesion site, in the acute or sub-acute phase (0-14 days post-injury). Far fewer chronic SCI studies have been undertaken. In addition, comparatively fewer studies have administered neurotrophic factors directly to the cell bodies of injured neurons; yet in other instructive rodent models of CNS injury, for example optic nerve crush or transection, therapies are targeted directly at the injured neurons themselves, the retinal ganglion cells. The mode of delivery of neurotrophic factors is also an important variable, whether delivered by acute injection of recombinant proteins, sub-acute or chronic delivery using osmotic minipumps, cell-mediated delivery, delivery using polymer release vehicles or supporting bridges of some sort, or the use of gene therapy to modify neurons, glial cells or precursor/stem cells. Neurotrophic factors are often used in combination with cell or tissue grafts and/or other pharmacotherapeutic agents. Finally, the dose and time-course of delivery of trophic support should ideally be tailored to suit specific biological requirements, whether they relate to neuronal survival, axonal sparing/sprouting, or the long-distance regeneration of axons ending in a different mode of growth associated with terminal arborization and renewed synaptogenesis. This article is part of a Special Issue entitled SI: Spinal cord injury.

Human FGF1 promoter is active in ependymal cells and dopaminergic neurons in the brains of F1B-GFP transgenic mice

FGF1 is involved in multiple biological functions and exhibits the importance in neuroprotective effects. Our previous studies indicated that, in human brain and retina, the FGF1B promoter controlled the expression of FGF1. However, the exact function and regulation of FGF1 in brain is still unclear. Here, we generated F1B-GFP transgenic mice that expressed the GFP reporter gene under the control of human FGF1B promoter (-540 to +31). Using the fresh brain sections of F1B-GFP transgenic mice, we found that the F1B-GFP cells expressed strong fluorescent signals in the ventricular system throughout the brain. The results of immunohistochemistry further showed that two distinct populations of F1B-GFP(+) cells existed in the brains of F1B-GFP transgenic mice. We demonstrated that one population of F1B-GFP(+) cells was ependymal cells, which distributed along the entire ventricles, and the second population of F1B-GFP(+) cells was neuronal cells that projected their long processes into multiple directions in specific areas of the brain. The double labeling of F1B-GFP(+) cells and tyrosine hydroxylase indicated that a subpopulation of F1B-GFP(+) -neuronal cells was dopaminergic neurons. Importantly, these F1B-GFP(+) /TH(+) cells were distributed in the main dopaminergic neuronal groups including hypothalamus, ventral tegmental area, and raphe nuclei. These results suggested that human FGF1B promoter was active in ependymal cells, neurons, and a portion of dopaminergic neurons. Thus, the F1B-GFP transgenic mice provide an animal model not only for studying FGF1 gene expression in vivo but also for understanding the role of FGF1 contribution in neurodegenerative disorders such as Parkinson's disease and Alzheimer's disease.

Functional regeneration beyond the glial scar

Astrocytes react to CNS injury by building a dense wall of filamentous processes around the lesion. Stromal cells quickly take up residence in the lesion core and synthesize connective tissue elements that contribute to fibrosis. Oligodendrocyte precursor cells proliferate within the lesion and entrap dystrophic axon tips. Here we review evidence that this aggregate scar acts as the major barrier to regeneration of axons after injury. We also consider several exciting new interventions that allow axons to regenerate beyond the glial scar, and discuss the implications of this work for the future of regeneration biology.

A Study of the Effect of Shiunko, a Traditional Chinese Herbal Medicine, on Fibroblasts and Its Implication on Wound Healing Processes

SIGNIFICANCE

In China, traditional Chinese medicine (TCM) has been used for thousands of years for various acute and chronic wound care. Thus, there is a growing need to explore the possible benefits of TCM on wound healing.

RECENT ADVANCES

Nowadays, in China and some Asian countries including Korea, Japan, and Singapore, Chinese herbal therapy is used as an alternative treatment in wound care. Therefore, exploration of the possible benefits of TCM on wound healing is necessary.

CRITICAL ISSUES

Development of TCM is based on the concept of Yin (negative phenomenon of nature) and Yang (positive phenomenon of nature). These opposing and complementary natural phenomena of the universe restore the normal physiological functions, consequently curing diseases and restoring health of a patient.

FUTURE DIRECTIONS

Due to lack of evidence-based research, TCM treatments are not widely accepted in the western world. Using state-of-the-art technology such as proteomics, bioinformatics, and biomolecular techniques, research studies may lead to more effective remedies for wound care in the future.

Host reaction to poly(2-hydroxyethyl methacrylate) scaffolds in a small spinal cord injury model

Tissue engineered scaffolds and matrices have been investigated over the past decade for their potential in spinal cord repair. They provide a 3-D substrate that can be permissive for nerve regeneration yet have other roles including neuroprotection, altering the inflammatory cascade and mechanically stabilizing spinal cord tissue after injury. In this study we investigated very small lesions (approx. 0.25 μL in volume) of the dorsal column into which a phase-separated poly(2-hydroxyethyl methacrylate) hydrogel scaffold is implanted. Using fluorescent immunohistochemistry to quantify glial scarring, the poly(2-hydroxyethyl methacrylate) scaffold group showed reduced intensity compared to lesion controls for GFAP and the chondroitin sulfate proteoglycan neurocan after 6 days. However, the scaffold and tissue was also pushed dorsally after 6 days while the scaffold was not integrated into the spinal cord after 28 days. Overall, this small-lesion spinal cord injury model provided information on the host tissue reaction of a TE scaffold while reducing animal discomfort and care.

Proteomic study on the protective mechanism of fibroblast growth factor 21 to ischemia-reperfusion injury

Fibroblast growth factor (FGF)-21 is a novel regulator of insulin-independent glucose transport in 3T3-L1 adipocytes and has glucose and triglyceride lowering effects in rodent models of diabetes. In this study, we found that FGF-21 can significantly attenuate ischemia-reperfusion (I/R) induced damage in H9c2 cells (rat heart). However, it is unclear which signal transduction pathway is involved in the cardioprotective effect of FGF-21. Thus, this study was designed to investigate the potential mechanism induced by FGF-21. The results showed that FGF-21 treatment prevented the oxidative stress and apoptosis associated with I/R damage by reducing the levels of superoxide anions, inhibiting glycogen synthase kinase (GSK) 3β by activating Akt phosphorylation, and recovering the levels of ATP synthase pyruvate kinase isozymes M1 and protein kinase C, thereby improving energy supply. In summary, we conclude that FGF-21 protects H9c2 cells against I/R injury mainly through the Akt-GSK-3β-caspase-3 dependent pathway, preventing oxidative stress, and recovery of the energy supply.

SOX2 expression is upregulated in adult spinal cord after contusion injury in both oligodendrocyte lineage and ependymal cells

The upregulation of genes normally associated with development may occur in the adult after spinal cord injury (SCI). To test this, we performed real-time RT-PCR array analysis of mouse spinal cord mRNAs comparing embryonic day (E)14.5 spinal cord with intact adult and adult cord 1 week after a clinically relevant standardized contusion SCI. We found significantly increased expression of a large number of neural development- and stem cell-associated genes after SCI. These included Sox2 (sex determining region Y-box 2), a transcription factor that regulates self-renewal and potency of embryonic neural stem cells and is one of only a few key factors needed to induce pluripotency. In adult spinal cord of Sox2-EGFP mice, Sox2-EGFP was found mainly in the ependymal cells of the central canal. After SCI, both mRNA and protein levels of Sox2 were significantly increased at and near the injury site. By 1 day, Sox2 was upregulated in NG2(+) oligodendrocyte progenitor cells (OPC) in the spared white matter. By 3 days, Sox2-EGFP ependymal cells had increased proliferation and begun to form multiple layers and clusters of cells in the central lesion zone of the cord. Expression of Sox2 by NG2(+) cells had declined by 1 week, but increased numbers of other Sox2-expressing cells persisted for at least 4 weeks after SCI in both mouse and rat models. Thus, SCI upregulates many genes associated with development and neural stem cells, including the key transcription factor Sox2, which is expressed in a pool of cells that persists for weeks after SCI.

The molecular basis of wound healing processes induced by lithospermi radix: a proteomics and biochemical analysis

Lithospermi Radix (LR) is an effective traditional Chinese herb in various types of wound healing; however, its mechanism of action remains unknown. A biochemical and proteomic platform was generated to explore the biological phenomena associated with LR and its active component shikonin. We found that both LR ethanol extracts and shikonin are able to promote cell proliferation by up to 25%. The results of proteomic analysis revealed that twenty-two differentially expressed proteins could be identified when fibroblast cells were treated with LR or shikonin. The functions of those proteins are associated with antioxidant activity, antiapoptosis activity, the regulation of cell mobility, the secretion of collagen, the removal of abnormal proteins, and the promotion of cell proliferation, indicating that the efficacy of LR in wound healing may be derived from a synergistic effect on a number of factors induced by the herbal medicine. Furthermore, an animal model confirmed that LR is able to accelerate wound healing on the flank back of the SD rats. Together these findings help to pinpoint the molecular basis of wound healing process induced by LR.

Fgf-dependent glial cell bridges facilitate spinal cord regeneration in zebrafish

Adult zebrafish show a remarkable capacity to regenerate their spinal column after injury, an ability that stands in stark contrast to the limited repair that occurs within the mammalian CNS post-injury. The reasons for this interspecies difference in regenerative capacity remain unclear. Here we demonstrate a novel role for Fgf signaling during glial cell morphogenesis in promoting axonal regeneration after spinal cord injury. Zebrafish glia are induced by Fgf signaling, to form an elongated bipolar morphology that forms a bridge between the two sides of the resected spinal cord, over which regenerating axons actively migrate. Loss of Fgf function inhibits formation of this "glial bridge" and prevents axon regeneration. Despite the poor potential for mammalian axonal regeneration, primate astrocytes activated by Fgf signaling adopt a similar morphology to that induced in zebrafish glia. This suggests that differential Fgf regulation, rather than intrinsic cell differences, underlie the distinct responses of mammalian and zebrafish glia to injury.

A Study of the Wound Healing Mechanism of a Traditional Chinese Medicine, Angelica sinensis, Using a Proteomic Approach

Angelica sinensis (AS) is a traditional Chinese herbal medicine that has been formulated clinically to treat various form of skin trauma and to help wound healing. However, the mechanism by which it works remains a mystery. In this study we have established a new platform to evaluate the pharmacological effects of total AS herbal extracts as well as its major active component, ferulic acid (FA), using proteomic and biochemical analysis. Cytotoxic and proliferation-promoting concentrations of AS ethanol extracts (AS extract) and FA were tested, and then the cell extracts were subject to 2D PAGE analysis. We found 51 differentially expressed protein spots, and these were identified by mass spectrometry. Furthermore, biomolecular assays, involving collagen secretion, migration, and ROS measurements, gave results that are consistent with the proteomic analysis. In this work, we have demonstrated a whole range of pharmacological effects associated with Angelica sinensis that might be beneficial when developing a wound healing pharmaceutical formulation for the herbal medicine.

Adeno-associated virus-mediated human acidic fibroblast growth factor expression promotes functional recovery of spinal cord-contused rats

BACKGROUND

Following spinal cord injury, the delivery of neurotrophic factors to the injured spinal cord has been shown to promote axonal regeneration and functional recovery. In previous studies, we showed that acidic fibroblast growth factor (aFGF) is a potent neurotrophic factor that promotes the regeneration of axotomized spinal cord or dorsal root ganglion neurones.

METHODS

We constructed a recombinant adeno-associated virus (AAV) vector to express human aFGF and evaluated aFGF expression and function in AAV-aFGF-infected PC12 cells. We analyzed AAV-green fluorescent protein (GFP) tropism and AAV-mediated aFGF expression in contused spinal cords. Animals received behavioural testing to evaluate the functional recovery.

RESULTS

Overexpression of aFGF was shown in AAV-aFGF-infected PC12 cells in a dose-dependent manner. Concurrently, neurite extension and cell number were significantly increased in AAV-aFGF infected cells. AAV-mediated GFP expression persisted for at least 5 weeks in contused spinal cords, and the most prominently transduced cells were neurones. Contusive injury reduced endogenous aFGF expression in spinal cords. Overexpression of aFGF was demonstrated in AAV-aFGF transduced spinal cords compared to AAV-GFP transduced spinal cords at 3 and 14 days post-injury. Evaluation of motor function revealed that the improvement of AAV-aFGF-treated rats was prominent. Both AAV-aFGF- and recombinant human aFGF-treated rats revealed significantly better recovery at 5 weeks post-injury, compared to vehicle- and AAV-GFP-treated rats.

CONCLUSIONS

These data suggest that supplement of aFGF improve the functional recovery of spinal cord-contused rats and that AAV-aFGF-mediated gene transfer could be a clinically feasible therapeutic approach for patients after nervous system injuries.

Acid fibroblast growth factor and peripheral nerve grafts regulate Th2 cytokine expression, macrophage activation, polyamine synthesis, and neurotrophin expression in transected rat spinal cords

Spinal cord injury elicits an inflammatory response that recruits macrophages to the injured spinal cord. Quantitative real-time PCR results have shown that a repair strategy combining peripheral nerve grafts with acidic fibroblast growth factor (aFGF) induced higher interleukin-4 (IL-4), IL-10, and IL-13 levels in the graft areas of rat spinal cords compared with transected spinal cords at 10 and 14 d. This led to higher arginase I-positive alternatively activated macrophage (M2 macrophage) responses. The gene expression of several enzymes involved in polyamine biosynthesis pathways was also upregulated in the graft areas of repaired spinal cords. The treatment induced a twofold upregulation of polyamine levels at 14 d, as confirmed by HPLC. Polyamines are important for the repair process, as demonstrated by the observation that treatment with inhibitors of arginase I and ornithine decarboxylase attenuates the functional recoveries of repaired rats. After 14 d, the treatment also induced the expression of neurotrophin nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), as well as M2 macrophages within grafted nerves expressing BDNF. IL-4 was upregulated in the injury sites of transected rats that received aFGF alone compared with those that received nerve grafts alone at 10 d. Conversely, nerve graft treatment induced NGF and BDNF expression at 14 d. Macrophages expressing polyamines and BDNF may benefit axonal regeneration at 14 d. These results indicate that aFGF and nerve grafts regulate different macrophage responses, and M2 macrophages may play an important role in axonal regeneration after spinal cord injury in rats.

Acidic fibroblast growth factor for repair of human spinal cord injury: a clinical trial

OBJECT

The study aimed to verify the safety and feasibility of applying acidic fibroblast growth factor (aFGF) with fibrin glue in combination with surgical neurolysis for nonacute spinal cord injury.

METHODS

This open-label, prospective, uncontrolled human clinical trial recruited 60 patients with spinal cord injuries (30 cervical and 30 thoracolumbar). The mean patient age was 36.5 ± 15.33 (mean ± SD) years, and the male/female ratio was 3:1. The mean time from injury to treatment was 25.7 ± 26.58 months, and the cause of injury included motor vehicle accident (26 patients [43.3%]), fall from a height (17 patients [28.3%]), sports (4 patients [6.7%]), and other (13 patients [21.7%]). Application of aFGF with fibrin glue and duraplasty was performed via laminectomy, and an adjuvant booster of combined aFGF and fibrin glue (2 ml) was given at 3 and 6 months postsurgery via lumbar puncture. Outcome measurements included the American Spinal Injury Association (ASIA) motor scores, sensory scores, impairment scales, and neurological levels. Examination of functional independence measures, visual analog scale, MR imaging, electrophysiological and urodynamic studies, hematology and biochemistry tests, tumor markers, and serum inflammatory cytokines were all conducted. All adverse events were monitored and reported. Exclusions were based on refusal, unrelated adverse events, or failure to participate in the planned rehabilitation.

RESULTS

Forty-nine patients (26 with cervical and 23 with thoracolumbar injuries) completed the 24-month trial. Compared with preoperative conditions, the 24-month postoperative ASIA motor scores improved significantly in the cervical group (from 27.6 ± 15.55 to 37.0 ± 19.93, p < 0.001) and thoracolumbar group (from 56.8 ± 9.21 to 60.7 ± 10.10, p < 0.001). The ASIA sensory scores also demonstrated significant improvement in light touch and pinprick in both groups: from 55.8 ± 24.89 to 59.8 ± 26.47 (p = 0.049) and 56.3 ± 23.36 to 62.3 ± 24.87 (p = 0.003), respectively, in the cervical group and from 75.7 ± 15.65 to 79.2 ± 15.81 (p < 0.001) and 78.2 ± 14.72 to 82.7 ± 16.60 (p < 0.001), respectively, in the thoracolumbar group. At 24-month follow-up, the ASIA impairment scale improved significantly in both groups (30% cervical [p = 0.011] and 30% thoracolumbar [p = 0.003]). There was also significant improvement in neurological level in the cervical (from 5.17 ± 1.60 to 6.27 ± 3.27, p = 0.022) and thoracolumbar (from 18.03 ± 4.19 to 18.67 ± 3.96, p = 0.001) groups. The average sum of motor items in functional independence measure also had significant improvement in both groups (p < 0.05). The walking/wheelchair locomotion subscale showed increased percentages of patients who were ambulatory (from 3.4% to 13.8% and from 17.9% to 35.7% in the cervical and thoracolumbar groups, respectively). There were no related adverse events.

CONCLUSIONS

The use of aFGF for spinal cord injury was safe and feasible in the present trial. There were significant improvements in ASIA motor and sensory scale scores, ASIA impairment scales, neurological levels, and functional independence measure at 24 months after treatment. Further large-scale, randomized, and controlled investigations are warranted to evaluate the efficacy and long-term results.

Effect of subcutaneous injection of [Ala]16-aFGF(1-29) on slow transit constipation in mice

AIM: To investigate the potential therapeutical effect of a new acidic fibroblast growth factor (aFGF) fragment - [Ala]¹⁶-aFGF(1-29) against slow transit constipation (STC) in mice and to explore possible mechanisms involved.

METHODS: Sixty ICR mice were divided randomly and equally into test group and control group. A mouse model of STC was established by subcutaneous injection (SC) of morphine [2.5 mg/(kg•d)] for 45 days. The control group was treated with normal saline for the same duration. The fecal character was observed according to the Bristol Stool Form Scale (BSFS), and only mice producing stools conforming to BSFS 1 and 2 were used as STC models. On day 45, six mice were chosen randomly from each group and used to confirm if STC was successfully induced by charcoal propulsion test. The rest mice in each group were divided into test group 1, test group 2, control group 1, and control group 2 (n = 12 each). The test group 1 and control group 1 were treated with [Ala]¹⁶-aFGF(1-29) (300 µg/kg each time, SC) twice per week for 8 weeks, while the test group 2 and control group 2 were treated with the same volume of vehicle. Fecal character was observed in all mice. Eight weeks later, the intestinal propulsion rate (IPR) in mice of each group was measured and the expression of neuron-specific enolase (NSE, a neuronal maker) in the colon was detected by immunohistochemistry and Western blot.

RESULTS: On day 45, the feces in the test group was drier and harder (BSFS 1 and 2) than the control group (BSFS 4 and 5). Both the IPR and expression level of NSE in the test group were significantly lower than those in the control group (63.422% ± 1.791% vs 55.702% ± 1.806%, 1.18800 ± 0.03176 vs 0.88730 ± 0.03554, 0.90520 ± 0.02268 vs 0.71300 ± 0.01654, all P < 0.05 or 0.01). Eight weeks after treatment, the feces in the test group 1 gradually became as smooth and soft (BSFS 4 and 5) as that in the control groups 1 and 2; the IPR and expression level of NSE in colonic tissue in the test group 1 were obviously improved compared to the test group 2 (62.250% ± 5.283% vs 57.190% ± 4.291%, 0.6543 ± 0.0069 vs 0.4193 ± 0.0158, 0.5823 ± 0.019 vs 0.5171 ± 0.0124, all P < 0.05) but showed no significant difference with those in the control groups 1 and 2.

CONCLUSION: Treatment with [Ala]¹⁶-aFGF (1-29) improved constipation symptoms and IPR in STC mice at least partially by protection of the enteric nervous system.

Reduction in antioxidant enzyme expression and sustained inflammation enhance tissue damage in the subacute phase of spinal cord contusive injury

BACKGROUND

Traumatic spinal cord injury (SCI) forms a disadvantageous microenvironment for tissue repair at the lesion site. To consider an appropriate time window for giving a promising therapeutic treatment for subacute and chronic SCI, global changes of proteins in the injured center at the longer survival time points after SCI remains to be elucidated.

METHODS

Through two-dimensional electrophoresis (2DE)-based proteome analysis and western blotting, we examined the differential expression of the soluble proteins isolated from the lesion center (LC) at day 1 (acute) and day 14 (subacute) after a severe contusive injury to the thoracic spinal cord at segment 10. In situ apoptotic analysis was used to examine cell apoptosis in injured spinal cord after adenoviral gene transfer of antioxidant enzymes. In addition, administration of chondroitinase ABC (chABC) was performed to analyze hindlimb locomotor recovery in rats with SCI using Basso, Beattie and Bresnahan (BBB) locomotor rating scale.

RESULTS

Our results showed a decline in catalase (CAT) and Mn-superoxide dismutase (MnSOD) found at day 14 after SCI. Accordingly, gene transfer of SOD was introduced in the injured spinal cord and found to attenuate cell apoptosis. Galectin-3, β-actin, actin regulatory protein (CAPG), and F-actin-capping protein subunit β (CAPZB) at day 14 were increased when compared to that detected at day 1 after SCI or in sham-operated control. Indeed, the accumulation of β-actin+ immune cells was observed in the LC at day 14 post SCI, while most of reactive astrocytes were surrounding the lesion center. In addition, chondroitin sulfate proteoglycans (CSPG)-related proteins with 40-kDa was detected in the LC at day 3-14 post SCI. Delayed treatment with chondroitinase ABC (chABC) at day 3 post SCI improved the hindlimb locomotion in SCI rats.

CONCLUSIONS

Our findings demonstrate that the differential expression in proteins related to signal transduction, oxidoreduction and stress contribute to extensive inflammation, causing time-dependent spread of tissue damage after severe SCI. The interventions by supplement of anti-oxidant enzymes right after SCI or delayed administration with chABC can facilitate spinal neural cell survival and tissue repair.

Fibroblast growth factors: biology, function, and application for tissue regeneration

Fibroblast growth factors (FGFs) that signal through FGF receptors (FGFRs) regulate a broad spectrum of biological functions, including cellular proliferation, survival, migration, and differentiation. The FGF signal pathways are the RAS/MAP kinase pathway, PI3 kinase/AKT pathway, and PLCγ pathway, among which the RAS/MAP kinase pathway is known to be predominant. Several studies have recently implicated the in vitro biological functions of FGFs for tissue regeneration. However, to obtain optimal outcomes in vivo, it is important to enhance the half-life of FGFs and their biological stability. Future applications of FGFs are expected when the biological functions of FGFs are potentiated through the appropriate use of delivery systems and scaffolds. This review will introduce the biology and cellular functions of FGFs and deal with the biomaterials based delivery systems and their current applications for the regeneration of tissues, including skin, blood vessel, muscle, adipose, tendon/ligament, cartilage, bone, tooth, and nerve tissues.

Glycosaminoglycans of the porcine central nervous system

Glycosaminoglycans (GAGs) are known to participate in central nervous system processes such as development, cell migration, and neurite outgrowth. In this paper, we report an initial glycomics study of GAGs from the porcine central nervous system. GAGs of the porcine central nervous system, brain and spinal cord were isolated and purified by defatting, proteolysis, anion-exchange chromatography, and methanol precipitation. The isolated GAG content in brain was 5 times higher than in spinal cord (0.35 mg/g of dry sample, compared to 0.07 mg/g of dry sample). In both tissues, chondroitin sulfate (CS) and heparan sulfate (HS) were the major and the minor GAG, respectively. The average molecular masses of CS from brain and spinal cord were 35.5 and 47.1 kDa, respectively, and those for HS from brain and spinal cord were 56.9 and 34 kDa, respectively. The disaccharide analysis showed that the compositions of CS from brain and spinal cords are similar, with uronic acid (1→3) 4-O-sulfo-N-acetylgalactosamine residue corresponding to the major disaccharide unit (CS type A) along with five minor disaccharide units. The major disaccharides of both brain and spinal cord HS were uronic acid (1→4) N-acetylglucosamine and uronic acid (1→4) 6-O-sulfo-N-sulfoglucosamine, but their composition of minor disaccharides differed. Analysis by (1)H and two-dimensional NMR spectroscopy confirmed these disaccharide analyses and provided the glucuronic/iduronic acid ratio. Finally, both purified CS and HS were biotinylated and immobilized on BIAcore SA biochips. Interactions between these GAGs and fibroblast growth factors (FGF1 and FGF2) and sonic hedgehog (Shh) were investigated by surface plasmon resonance.