Dorsal root ganglia neurons gradually lose their axonal regeneration ability during development and aging.To explore molecules that enhance axonal regeneration,we screened growth factors with differential gene express...Dorsal root ganglia neurons gradually lose their axonal regeneration ability during development and aging.To explore molecules that enhance axonal regeneration,we screened growth factors with differential gene expression patterns in the dorsal root ganglias of young adult and aged animals following sciatic nerve injury.In young adult animals,two transforming growth factor beta-related factors,activin A and angiopoietin 2,were found to be upregulated post nerve injury.Treatment of isolated dorsal root ganglia explants and cultured dorsal root ganglia neurons of neonatal and young adult rats with recombinant activin A or angiopoietin 2 protein stimulated neurite outgrowth and axonal elongation.The administration of recombinant activin A or angiopoietin 2 protein to sciatic nerve crush-injured dorsal root ganglias also supported the growth of sensory neurons and facilitated nerve regeneration in both young adult and aged rats.Using RNA sequencing,we characterized genetic changes in dorsal root ganglia neurons following recombinant activin A or angiopoietin 2 treatment,revealing the unique mechanisms of these transforming growth factor beta-related factors.Recombinant activin A elicited changes in the gene expression of cytoskeleton-related Gper1 and activated extracellular signal-regulated kinase signaling,while angiopoietin 2 increased the expression of the transcription factor gene E2f2.Our identification of activin A and angiopoietin 2 as crucial promotional factors of axonal regeneration may guide future therapeutic strategies for the treatment of nerve injury.展开更多
The mature central nervous system(CNS,composed of the brain,spinal cord,olfactory and optic nerves)is unable to regenerate spontaneously after an insult,both in the cases of neurodegenerative diseases(for example Alzh...The mature central nervous system(CNS,composed of the brain,spinal cord,olfactory and optic nerves)is unable to regenerate spontaneously after an insult,both in the cases of neurodegenerative diseases(for example Alzheimer's or Parkinson's disease)or traumatic injuries(such as spinal cord lesions).In the last 20 years,the field has made significant progress in unlocking axon regrowth.展开更多
Alzheimer’s disease is a multi-amyloidosis disease characterized by amyloid-βdeposits in brain blood vessels,microaneurysms,and senile plaques.How amyloid-βdeposition affects axon pathology has not been examined ex...Alzheimer’s disease is a multi-amyloidosis disease characterized by amyloid-βdeposits in brain blood vessels,microaneurysms,and senile plaques.How amyloid-βdeposition affects axon pathology has not been examined extensively.We used immunohistochemistry and immunofluorescence staining to analyze the forebrain tissue slices of Alzheimer’s disease patients.Widespread axonal amyloidosis with distinctive axonal enlargement was observed in patients with Alzheimer’s disease.On average,amyloid-β-positive axon diameters in Alzheimer’s disease brains were 1.72 times those of control brain axons.Furthermore,axonal amyloidosis was associated with microtubule-associated protein 2 reduction,tau phosphorylation,lysosome destabilization,and several blood-related markers,such as apolipoprotein E,alpha-hemoglobin,glycosylated hemoglobin type A1C,and hemin.Lysosome destabilization in Alzheimer’s disease was also clearly identified in the neuronal soma,where it was associated with the co-expression of amyloid-β,Cathepsin D,alpha-hemoglobin,actin alpha 2,and collagen type IV.This suggests that exogenous hemorrhagic protein intake influences neural lysosome stability.Additionally,the data showed that amyloid-β-containing lysosomes were 2.23 times larger than control lysosomes.Furthermore,under rare conditions,axonal breakages were observed,which likely resulted in Wallerian degeneration.In summary,axonal enlargement associated with amyloidosis,micro-bleeding,and lysosome destabilization is a major defect in patients with Alzheimer’s disease.This finding suggests that,in addition to the well-documented neural soma and synaptic damage,axonal damage is a key component of neuronal defects in Alzheimer’s disease.展开更多
The field of neurodegeneration research has long been focused on finding therapeutic strategies to effectively decrease or halt neuronal loss while minimizing side effects.A recent study titled“Inhibiting acute,axona...The field of neurodegeneration research has long been focused on finding therapeutic strategies to effectively decrease or halt neuronal loss while minimizing side effects.A recent study titled“Inhibiting acute,axonal DLK palmitoylation is neuroprotective and avoids deleterious effects of cell-wide DLK inhibition”(Zhang et al.,2025),describes an innovative approach to achieve this goal.The authors target a specific post-translational modification of dual leucine-zipper kinase(DLK),palmitoylation,to selectively inhibit DLK-dependent pro-degenerative signaling and protect neurons,thereby revealing a new way to intervene and block neurodegeneration.This Perspective aims to explore the significance of these findings and propose directions for future research.展开更多
The fibrotic scar due to excessive deposition of extracellular matrix(ECM)after spinal cord injury(SCI)remains one of formidable challenges to axonal regeneration.Previous therapeutic strategies mainly focus on elimin...The fibrotic scar due to excessive deposition of extracellular matrix(ECM)after spinal cord injury(SCI)remains one of formidable challenges to axonal regeneration.Previous therapeutic strategies mainly focus on eliminating fibrotic scars by blocking(Göritz et al.,2011)or inhibiting(Dias et al.,2018)the generation of scar-forming stromal cells,as well as inducing their migratory defect(Hellal et al.,2011;Ruschel et al.,2015).展开更多
Aging is characterized by a decreased autophagic activity contributing to the intracellular deposition of damaged organelles and macromolecules.Autophagy is particularly challenging in neurons since autophagic vesicle...Aging is characterized by a decreased autophagic activity contributing to the intracellular deposition of damaged organelles and macromolecules.Autophagy is particularly challenging in neurons since autophagic vesicles are formed at the axonal tip and must be transported to the soma where final degradation occurs.Here,we examined if axonal transport of autophagic vesicles is altered during aging.We employed two-photon microscopy for in vivo imaging in the optic nerve of young and aged rats.In old animals(>18 months old),retrograde autophagic vesicle transport was significantly reduced with regard to motility and velocity.While activation of autophagy was decreased,expression of key proteins of the autophagy-lysosomal pathway including p62 and procathepsin D and the number of autophagolysosomes was increased.Maturation of autophagic vesicles was shifted to more distal regions of the axon and axonal lysosomal clearing was impaired.In a pull-down assay,the protein binding between dynein and dynactin was decreased by half,which could explain the retrograde axonal transport effects.Taken together,retrograde axonal autophagic vesicle transport in vivo is diminished during aging accompanied by decreased autophagy activation,alterations of the lysosomal pathway,and a reduced dynein-dynactin binding.展开更多
Stem cell therapy shows promise for treating brain injuries;neural stem cells in particular are capable of repairing damage by forming new nerve cells and supporting recovery.However,optimizing the implantation and fu...Stem cell therapy shows promise for treating brain injuries;neural stem cells in particular are capable of repairing damage by forming new nerve cells and supporting recovery.However,optimizing the implantation and functionality of these cells in damaged brain regions remains challenging.Silk fibroin,a natural protein derived from silkworm silk,is a biocompatible material with exceptional properties that are useful for tissue engineering.Its biodegradability,mechanical robustness,and ability to promote cell growth make it particularly valuable for biomedical applications.Silk fibroin nanomaterials,which comprise silk fibroin processed into nanostructures,offer enhanced surface area,improved loading capacity for bioactive molecules,and superior nanoscale interactions with cells compared with bulk silk fibroin materials.In this study,we first extracted human-derived neural stem cells from a 14-week-old human fetus.Then,neural stem cells were loaded with 1%silk fibroin nanomaterials,which was identified as the optimal concentration to support human-derived neural stem cell growth and release of neurotrophic factors.Finally,1%silk fibroin nanomaterials were implanted into a rat model of hypoxic-ischemic brain injury.The results showed that,compared with the treatment with human-derived neural stem cells alone,silk fibroin hydrogel carrying human-derived neural stem cells was significantly more effective at alleviating brain tissue damage,increasing neurotrophic factor secretion in the brain microenvironment,and promoting motor and cognitive function recovery.These findings suggest that silk fibroin nanomaterials loaded with human-derived neural stem cells could be used to treat hypoxic-ischemic encephalopathy.However,the mechanisms and related signaling pathways by which hydrogels combined with cells exert their reparative effects still require further in-depth investigation.展开更多
Amyotrophic lateral sclerosis is characterized by the progressive loss of motor neurons.Early-stage axonal dysfunction,rather than central nervous system injury,plays a key role in the disease process.However,the mole...Amyotrophic lateral sclerosis is characterized by the progressive loss of motor neurons.Early-stage axonal dysfunction,rather than central nervous system injury,plays a key role in the disease process.However,the molecular mechanisms underlying this dysfunction remain unclear.To investigate the relationship between peripheral immune dysregulation and axonal dysfunction in amyotrophic lateral sclerosis,we recruited 372 patients within the first 12 months of sporadic amyotrophic lateral sclerosis onset between January 2018 and May 2024.We collected peripheral immune markers at baseline,including total leukocytes,lymphocytes,monocytes,neutrophils,basophils,eosinophils,and platelets.We also calculated four derived ratios:neutrophil-to-lymphocyte ratio,platelet-to-lymphocyte ratio,lymphocyte-to-monocyte ratio,and systemic immune inflammation index.Multivariate analysis,adjusted for confounding factors,revealed that higher counts of total leukocytes and neutrophils,as well as higher neutrophil-related ratios,including the neutrophil to lymphocyte ratio and the systemic immune inflammation index,were significantly correlated with higher compound muscle action potential scores.Stratified analyses revealed that these associations varied by age and sex.Furthermore,mediation analysis demonstrated that axonal dysfunction plays a significant role in the relationship between immune markers and disease progression.These findings emphasize the critical role that peripheral immune dysregulation plays in amyotrophic lateral sclerosis progression by mediating peripheral nerve injury,particularly in the early stages of the disease.This study highlights the importance of the peripheral nervous system in the early stages of amyotrophic lateral sclerosis and provides new insights into disease mechanisms and potential therapeutic targets.展开更多
Acute mitochondrial damage and the energy crisis following axonal injury highlight mitochondrial transport as an important target for axonal regeneration.Syntaphilin(Snph),known for its potent mitochondrial anchoring ...Acute mitochondrial damage and the energy crisis following axonal injury highlight mitochondrial transport as an important target for axonal regeneration.Syntaphilin(Snph),known for its potent mitochondrial anchoring action,has emerged as a significant inhibitor of both mitochondrial transport and axonal regeneration.Therefore,investigating the molecular mechanisms that influence the expression levels of the snph gene can provide a viable strategy to regulate mitochondrial trafficking and enhance axonal regeneration.Here,we reveal the inhibitory effect of microRNA-146b(miR-146b)on the expression of the homologous zebrafish gene syntaphilin b(snphb).Through CRISPR/Cas9 and single-cell electroporation,we elucidated the positive regulatory effect of the miR-146b-snphb axis on Mauthner cell(M-cell)axon regeneration at the global and single-cell levels.Through escape response tests,we show that miR-146b-snphb signaling positively regulates functional recovery after M-cell axon injury.In addition,continuous dynamic imaging in vivo showed that reprogramming miR-146b significantly promotes axonal mitochondrial trafficking in the pre-injury and early stages of regeneration.Our study reveals an intrinsic axonal regeneration regulatory axis that promotes axonal regeneration by reprogramming mitochondrial transport and anchoring.This regulation involves noncoding RNA,and mitochondria-associated genes may provide a potential opportunity for the repair of central nervous system injury.展开更多
During the development of the nervous system,there is an overproduction of neurons and synapses.Hebbian competition between neighboring nerve endings and synapses performing different activity levels leads to their el...During the development of the nervous system,there is an overproduction of neurons and synapses.Hebbian competition between neighboring nerve endings and synapses performing different activity levels leads to their elimination or strengthening.We have extensively studied the involvement of the brain-derived neurotrophic factor-Tropomyosin-related kinase B receptor neurotrophic retrograde pathway,at the neuromuscular junction,in the axonal development and synapse elimination process versus the synapse consolidation.The purpose of this review is to describe the neurotrophic influence on developmental synapse elimination,in relation to other molecular pathways that we and others have found to regulate this process.In particular,we summarize our published results based on transmitter release analysis and axonal counts to show the different involvement of the presynaptic acetylcholine muscarinic autoreceptors,coupled to downstream serine-threonine protein kinases A and C(PKA and PKC)and voltage-gated calcium channels,at different nerve endings in developmental competition.The dynamic changes that occur simultaneously in several nerve terminals and synapses converge across a postsynaptic site,influence each other,and require careful studies to individualize the mechanisms of specific endings.We describe an activity-dependent balance(related to the extent of transmitter release)between the presynaptic muscarinic subtypes and the neurotrophin-mediated TrkB/p75NTR pathways that can influence the timing and fate of the competitive interactions between the different axon terminals.The downstream displacement of the PKA/PKC activity ratio to lower values,both in competing nerve terminals and at postsynaptic sites,plays a relevant role in controlling the elimination of supernumerary synapses.Finally,calcium entry through L-and P/Q-subtypes of voltage-gated calcium channels(both channels are present,together with the N-type channel in developing nerve terminals)contributes to reduce transmitter release and promote withdrawal of the most unfavorable nerve terminals during elimination(the weakest in acetylcholine release and those that have already become silent).The main findings contribute to a better understanding of punishment-rewarding interactions between nerve endings during development.Identifying the molecular targets and signaling pathways that allow synapse consolidation or withdrawal of synapses in different situations is important for potential therapies in neurodegenerative diseases.展开更多
Rab5 is a GTPase protein that is involved in intracellular membrane trafficking. It functions by binding to various effector proteins and regulating cellular responses, including the formation of transport vesicles an...Rab5 is a GTPase protein that is involved in intracellular membrane trafficking. It functions by binding to various effector proteins and regulating cellular responses, including the formation of transport vesicles and their fusion with the cellular membrane. Rab5 has been reported to play an important role in the development of the zebrafish embryo;however, its role in axonal regeneration in the central nervous system remains unclear. In this study, we established a zebrafish Mauthner cell model of axonal injury using single-cell electroporation and two-photon axotomy techniques. We found that overexpression of Rab5 in single Mauthner cells promoted marked axonal regeneration and increased the number of intra-axonal transport vesicles. In contrast, treatment of zebrafish larvae with the Rab kinase inhibitor CID-1067700markedly inhibited axonal regeneration in Mauthner cells. We also found that Rab5 activated phosphatidylinositol 3-kinase(PI3K) during axonal repair of Mauthner cells and promoted the recovery of zebrafish locomotor function. Additionally, rapamycin, an inhibitor of the mechanistic target of rapamycin downstream of PI3K, markedly hindered axonal regeneration. These findings suggest that Rab5 promotes the axonal regeneration of injured zebrafish Mauthner cells by activating the PI3K signaling pathway.展开更多
Neuronal growth, extension, branching, and formation of neural networks are markedly influenced by the extracellular matrix—a complex network composed of proteins and carbohydrates secreted by cells. In addition to p...Neuronal growth, extension, branching, and formation of neural networks are markedly influenced by the extracellular matrix—a complex network composed of proteins and carbohydrates secreted by cells. In addition to providing physical support for cells, the extracellular matrix also conveys critical mechanical stiffness cues. During the development of the nervous system, extracellular matrix stiffness plays a central role in guiding neuronal growth, particularly in the context of axonal extension, which is crucial for the formation of neural networks. In neural tissue engineering, manipulation of biomaterial stiffness is a promising strategy to provide a permissive environment for the repair and regeneration of injured nervous tissue. Recent research has fine-tuned synthetic biomaterials to fabricate scaffolds that closely replicate the stiffness profiles observed in the nervous system. In this review, we highlight the molecular mechanisms by which extracellular matrix stiffness regulates axonal growth and regeneration. We highlight the progress made in the development of stiffness-tunable biomaterials to emulate in vivo extracellular matrix environments, with an emphasis on their application in neural repair and regeneration, along with a discussion of the current limitations and future prospects. The exploration and optimization of the stiffness-tunable biomaterials has the potential to markedly advance the development of neural tissue engineering.展开更多
Stress signaling following axon injury stimulates a transcriptional program for regeneration that might be exploited to promote central nervous system repair.However,this stress response drives neuronal apoptosis in n...Stress signaling following axon injury stimulates a transcriptional program for regeneration that might be exploited to promote central nervous system repair.However,this stress response drives neuronal apoptosis in non-regenerative environments.This duality presents a quandary for the development of therapeutic interventions:manipulating stress signaling to enhance recovery of damaged neurons risks accelerating neurodegeneration or restricting regenerative potential.This dichotomy is well illustrated by the fates of retinal ganglion cells(RGCs)following optic nerve crush.In this central nervous system injury model,disruption of a stress-activated MAP kinase(MAPK)cascade blocks the extensive apoptosis of RGCs that occurs in wild-type mice(Watkins et al.,2013;Welsbie et al.,2017).展开更多
Current treatments for epilepsy can only manage the symptoms of the condition but cannot alter the initial onset or halt the progression of the disease. Consequently, it is crucial to identify drugs that can target no...Current treatments for epilepsy can only manage the symptoms of the condition but cannot alter the initial onset or halt the progression of the disease. Consequently, it is crucial to identify drugs that can target novel cellular and molecular mechanisms and mechanisms of action. Increasing evidence suggests that axon guidance molecules play a role in the structural and functional modifications of neural networks and that the dysregulation of these molecules is associated with epilepsy susceptibility. In this review, we discuss the essential role of axon guidance molecules in neuronal activity in patients with epilepsy as well as the impact of these molecules on synaptic plasticity and brain tissue remodeling. Furthermore, we examine the relationship between axon guidance molecules and neuroinflammation, as well as the structural changes in specific brain regions that contribute to the development of epilepsy. Ample evidence indicates that axon guidance molecules, including semaphorins and ephrins, play a fundamental role in guiding axon growth and the establishment of synaptic connections. Deviations in their expression or function can disrupt neuronal connections, ultimately leading to epileptic seizures. The remodeling of neural networks is a significant characteristic of epilepsy, with axon guidance molecules playing a role in the dynamic reorganization of neural circuits. This, in turn, affects synapse formation and elimination. Dysregulation of these molecules can upset the delicate balance between excitation and inhibition within a neural network, thereby increasing the risk of overexcitation and the development of epilepsy. Inflammatory signals can regulate the expression and function of axon guidance molecules, thus influencing axonal growth, axon orientation, and synaptic plasticity. The dysregulation of neuroinflammation can intensify neuronal dysfunction and contribute to the occurrence of epilepsy. This review delves into the mechanisms associated with the pathogenicity of axon guidance molecules in epilepsy, offering a valuable reference for the exploration of therapeutic targets and presenting a fresh perspective on treatment strategies for this condition.展开更多
In this paper, we present a simulation program that allows for the concurrent propagation of action potentials in axons coupled via currents, as well as, for the first time, the computation of the resultant nodal elec...In this paper, we present a simulation program that allows for the concurrent propagation of action potentials in axons coupled via currents, as well as, for the first time, the computation of the resultant nodal electric field generated as the action potentials traverse the tract of axons. With these fields in hand, we inject currents into nodes of axons that depend on these fields and study the coupling between axons in the presence of the fields and currents present jointly in varying strengths. We find close-to-synchronized propagation in three dimensions. Further, we derive for the first time a mathematical equation for tortuous tracts (as opposed to linear) with such field-mediated coupling. The geometrical formulation enables us to consider spacetime perturbative effects, which have also not been considered in the literature so far. We investigate the case when gravitational radiation is present, in order to determine its impact on tract information processing. We find that action potential relative-timing in a tract is affected by the strength and frequency of gravitational waves and the waning of this influence with weakening strength. This latter study blurs the division between what lies inside and outside man. As an additional novelty, we investigate the influence of geometry on the information transmission capacity of the ephaptically-coupled tract, when viewed as a discrete memoryless channel, and find a rising trend in capacity with increasing axonal inclinations, which may occur in traumatic CNS injury.展开更多
Objective:Treating peripheral nerve injury(PNI)presents a clinical challenge due to limited axon regeneration.Strychni Semen,a traditional Chinese medicine,is clinically used for numbness and hemiplegia.However,its ro...Objective:Treating peripheral nerve injury(PNI)presents a clinical challenge due to limited axon regeneration.Strychni Semen,a traditional Chinese medicine,is clinically used for numbness and hemiplegia.However,its role in promoting functional recovery after PNI and the related mechanisms have not yet been systematically studied.Methods:A mouse model of sciatic nerve crush(SNC)injury was established and the mice received drug treatment via intragastric gavage,followed by behavioral assessments(adhesive removal test,hot-plate test and Von Frey test).Transcriptomic analyses were performed to examine gene expression in the dorsal root ganglia(DRGs)from the third to the sixth lumbar vertebrae,so as to identify the significantly differentially expressed genes.Immunofluorescence staining was used to assess the expression levels of superior cervical ganglia neural-specific 10 protein(SCG10).The ultra-trace protein detection technique was used to evaluate changes in gene expression levels.Results:Strychni Semen and its active compounds(brucine and strychnine)improved functional recovery in mice following SNC injury.Transcriptomic data indicated that Strychni Semen and its active compounds initiated transcriptional reprogramming that impacted cellular morphology and extracellular matrix remodeling in DRGs after SNC,suggesting potential roles in promoting axon regeneration.Imaging data further confirmed that Strychni Semen and its active compounds facilitated axon regrowth in SNC-injured mice.By integrating protein–protein interaction predictions,ultra-trace protein detection,and molecular docking analysis,we identified myeloperoxidase as a potentially critical factor in the axon regenerative effects conferred by Strychni Semen and its active compounds.Conclusion:Strychni Semen and its active compounds enhance sensory function by promoting axonal regeneration after PNI.These findings establish a foundation for the future applications of Strychni Semen and highlight novel therapeutic strategies and drug targets for axon regeneration.展开更多
Erratum to:J Huazhong Univ Sci Technol[Med Sci]36(4):548–553,2016 https://doi.org/10.1007/s11596-016-1623-6 In the originally published article(https://doi.org/10.1007/s11596-016-1623-6),the immunofluorescence images...Erratum to:J Huazhong Univ Sci Technol[Med Sci]36(4):548–553,2016 https://doi.org/10.1007/s11596-016-1623-6 In the originally published article(https://doi.org/10.1007/s11596-016-1623-6),the immunofluorescence images in shRNA group in Fig.3 were accidentally used rather than the final,formal experiments.To retain consistency,the entire Fig.3 is replaced here with original images of the experiments.The authors declare that this correction will not affect the conclusion of the study.展开更多
Axonal degeneration is a key pathological feature in many neurological diseases. It often leads to persistent deficits due to the inability of axons to regenerate in the central nervous system. Therefore therapeutic a...Axonal degeneration is a key pathological feature in many neurological diseases. It often leads to persistent deficits due to the inability of axons to regenerate in the central nervous system. Therefore therapeutic approaches should optimally both attenuate axonal degeneration and foster axonal regeneration. Compelling evidence suggests that collapsin response mediator protein-2（CRMP2） might be a molecular target fulfilling these requirements. In this mini-review, we give a compact overview of the known functions of CRMP2 and its molecular interactors in neurite outgrowth and in neurodegenerative conditions. Moreover, we discuss in detail our recent findings on the role of CRMP2 in acute axonal degeneration in the optic nerve. We found that the calcium influx induced by the lesion activates the protease calpain which cleaves CRMP2, leading to impairment of axonal transport. Both calpain inhibition and CRMP2 overexpression effectively protected the proximal axons against acute axonal degeneration. Taken together, CRMP2 is further characterized as a central molecular player in acute axonal degeneration and thus evolves as a promising therapeutic target to both counteract axonal degeneration and foster axonal regeneration in neurodegenerative and neurotraumatic diseases.展开更多
Stroke remains the leading cause of long-term disability.Hemiparesis is one of the most common post-stroke motor deficits and is largely attributed to loss or disruption of the motor signals from the affected motor co...Stroke remains the leading cause of long-term disability.Hemiparesis is one of the most common post-stroke motor deficits and is largely attributed to loss or disruption of the motor signals from the affected motor cortex.As the only direct descending motor pathway,the corticospinal tract(CST)is the primary pathway to innervate spinal motor neurons,and thus,forms the neuroanatomical basis to control the peripheral muscles for voluntary movements.Here,we review evidence from both experimental animals and stroke patients,regarding CST axonal damage,functional contribution of CST axonal integrity and remodeling to neurological recovery,and therapeutic approaches aimed to enhance CST axonal remodeling after stroke.The new insights gleaned from preclinical and clinical studies may encourage the development of more rational therapeutics with a strategy targeted to promote axonal rewiring for corticospinal innervation,which will significantly impact the current clinical needs of subacute and chronic stroke treatment.展开更多
Nervous system disorders are prevalent health issues that will only continue to increase in frequency as the population ages.Dying-back axonopathy is a hallmark of many neurologic diseases and leads to axonal disconne...Nervous system disorders are prevalent health issues that will only continue to increase in frequency as the population ages.Dying-back axonopathy is a hallmark of many neurologic diseases and leads to axonal disconnection from their targets,which in turn leads to functional impairment.During the course of many of neurologic diseases,axons can regenerate or sprout in an attempt to reconnect with the target and restore synapse function.In amyotrophic lateral sclerosis(ALS),distal motor axons retract from neuromuscular junctions early in the disease-course before significant motor neuron death.There is evidence of compensatory motor axon sprouting and reinnervation of neuromuscular junctions in ALS that is usually quickly overtaken by the disease course.Potential drugs that enhance compensatory sprouting and encourage reinnervation may slow symptom progression and retain muscle function for a longer period of time in ALS and in other diseases that exhibit dying-back axonopathy.There remain many outstanding questions as to the impact of distinct disease-causing mutations on axonal outgrowth and regeneration,especially in regards to motor neurons derived from patient induced pluripotent stem cells.Compartmentalized microfluidic chambers are powerful tools for studying the distal axons of human induced pluripotent stem cells-derived motor neurons,and have recently been used to demonstrate striking regeneration defects in human motor neurons harboring ALS disease-causing mutations.Modeling the human neuromuscular circuit with human induced pluripotent stem cells-derived motor neurons will be critical for developing drugs that enhance axonal regeneration,sprouting,and reinnervation of neuromuscular junctions.In this review we will discuss compensatory axonal sprouting as a potential therapeutic target for ALS,and the use of compartmentalized microfluidic devices to find drugs that enhance regeneration and axonal sprouting of motor axons.展开更多
基金supported by Major Program of National Natural Science Foundation of China,No.92368207Frontier Leading Technology BasicResearch Major Project of Jiangsu Province,No.BK20232023(both to XG).
文摘Dorsal root ganglia neurons gradually lose their axonal regeneration ability during development and aging.To explore molecules that enhance axonal regeneration,we screened growth factors with differential gene expression patterns in the dorsal root ganglias of young adult and aged animals following sciatic nerve injury.In young adult animals,two transforming growth factor beta-related factors,activin A and angiopoietin 2,were found to be upregulated post nerve injury.Treatment of isolated dorsal root ganglia explants and cultured dorsal root ganglia neurons of neonatal and young adult rats with recombinant activin A or angiopoietin 2 protein stimulated neurite outgrowth and axonal elongation.The administration of recombinant activin A or angiopoietin 2 protein to sciatic nerve crush-injured dorsal root ganglias also supported the growth of sensory neurons and facilitated nerve regeneration in both young adult and aged rats.Using RNA sequencing,we characterized genetic changes in dorsal root ganglia neurons following recombinant activin A or angiopoietin 2 treatment,revealing the unique mechanisms of these transforming growth factor beta-related factors.Recombinant activin A elicited changes in the gene expression of cytoskeleton-related Gper1 and activated extracellular signal-regulated kinase signaling,while angiopoietin 2 increased the expression of the transcription factor gene E2f2.Our identification of activin A and angiopoietin 2 as crucial promotional factors of axonal regeneration may guide future therapeutic strategies for the treatment of nerve injury.
基金supported by ANR(ANR-21CE16-0008-01)ANR(ANR-21-CE16-0008-02 and ANR-23CE52-0007)+1 种基金UNADEV(A22018CS)(to HN)UNADEV(A22020CS)(to SB)。
文摘The mature central nervous system(CNS,composed of the brain,spinal cord,olfactory and optic nerves)is unable to regenerate spontaneously after an insult,both in the cases of neurodegenerative diseases(for example Alzheimer's or Parkinson's disease)or traumatic injuries(such as spinal cord lesions).In the last 20 years,the field has made significant progress in unlocking axon regrowth.
基金supported by the National Natural Science Foundation of China,No.81472235(to HF)the Shanghai Jiao Tong University Medical and Engineering Project,Nos.YG2021QN53(to HF),YG2017MS71(to HF)+1 种基金the International Cooperation Project of the National Natural Science Foundation of China,No.82020108017(to DC)the Innovation Group Project of the National Natural Science Foundation of China,No.81921002(to DC).
文摘Alzheimer’s disease is a multi-amyloidosis disease characterized by amyloid-βdeposits in brain blood vessels,microaneurysms,and senile plaques.How amyloid-βdeposition affects axon pathology has not been examined extensively.We used immunohistochemistry and immunofluorescence staining to analyze the forebrain tissue slices of Alzheimer’s disease patients.Widespread axonal amyloidosis with distinctive axonal enlargement was observed in patients with Alzheimer’s disease.On average,amyloid-β-positive axon diameters in Alzheimer’s disease brains were 1.72 times those of control brain axons.Furthermore,axonal amyloidosis was associated with microtubule-associated protein 2 reduction,tau phosphorylation,lysosome destabilization,and several blood-related markers,such as apolipoprotein E,alpha-hemoglobin,glycosylated hemoglobin type A1C,and hemin.Lysosome destabilization in Alzheimer’s disease was also clearly identified in the neuronal soma,where it was associated with the co-expression of amyloid-β,Cathepsin D,alpha-hemoglobin,actin alpha 2,and collagen type IV.This suggests that exogenous hemorrhagic protein intake influences neural lysosome stability.Additionally,the data showed that amyloid-β-containing lysosomes were 2.23 times larger than control lysosomes.Furthermore,under rare conditions,axonal breakages were observed,which likely resulted in Wallerian degeneration.In summary,axonal enlargement associated with amyloidosis,micro-bleeding,and lysosome destabilization is a major defect in patients with Alzheimer’s disease.This finding suggests that,in addition to the well-documented neural soma and synaptic damage,axonal damage is a key component of neuronal defects in Alzheimer’s disease.
基金supported by NIH(R01 NS094402 and R21 EY029386)Shriners Children’s(#85190 PHI and#87400 PHI)by BrightFocus Foundation(G2019267)(to GMT).
文摘The field of neurodegeneration research has long been focused on finding therapeutic strategies to effectively decrease or halt neuronal loss while minimizing side effects.A recent study titled“Inhibiting acute,axonal DLK palmitoylation is neuroprotective and avoids deleterious effects of cell-wide DLK inhibition”(Zhang et al.,2025),describes an innovative approach to achieve this goal.The authors target a specific post-translational modification of dual leucine-zipper kinase(DLK),palmitoylation,to selectively inhibit DLK-dependent pro-degenerative signaling and protect neurons,thereby revealing a new way to intervene and block neurodegeneration.This Perspective aims to explore the significance of these findings and propose directions for future research.
文摘The fibrotic scar due to excessive deposition of extracellular matrix(ECM)after spinal cord injury(SCI)remains one of formidable challenges to axonal regeneration.Previous therapeutic strategies mainly focus on eliminating fibrotic scars by blocking(Göritz et al.,2011)or inhibiting(Dias et al.,2018)the generation of scar-forming stromal cells,as well as inducing their migratory defect(Hellal et al.,2011;Ruschel et al.,2015).
基金China Scholarship Council(CSCto XL)and a generous heritage donation from Bettina Fischer,Germany(to JCK).
文摘Aging is characterized by a decreased autophagic activity contributing to the intracellular deposition of damaged organelles and macromolecules.Autophagy is particularly challenging in neurons since autophagic vesicles are formed at the axonal tip and must be transported to the soma where final degradation occurs.Here,we examined if axonal transport of autophagic vesicles is altered during aging.We employed two-photon microscopy for in vivo imaging in the optic nerve of young and aged rats.In old animals(>18 months old),retrograde autophagic vesicle transport was significantly reduced with regard to motility and velocity.While activation of autophagy was decreased,expression of key proteins of the autophagy-lysosomal pathway including p62 and procathepsin D and the number of autophagolysosomes was increased.Maturation of autophagic vesicles was shifted to more distal regions of the axon and axonal lysosomal clearing was impaired.In a pull-down assay,the protein binding between dynein and dynactin was decreased by half,which could explain the retrograde axonal transport effects.Taken together,retrograde axonal autophagic vesicle transport in vivo is diminished during aging accompanied by decreased autophagy activation,alterations of the lysosomal pathway,and a reduced dynein-dynactin binding.
基金Dalian Science and Technology Talent Innovation Support Policy Implementation Plan High-Level Talent Team,No.2022RG18(to JL)the Science and Technology Plan Orientation of Liaoning Province,No.[2021]49(to JL)+1 种基金Dalian High-Level Talent Innovation Support Plan,No.2021RQ028(to CH)Natural Science Foundation of Liaoning Province,No.2022-BS-238(to CH).
文摘Stem cell therapy shows promise for treating brain injuries;neural stem cells in particular are capable of repairing damage by forming new nerve cells and supporting recovery.However,optimizing the implantation and functionality of these cells in damaged brain regions remains challenging.Silk fibroin,a natural protein derived from silkworm silk,is a biocompatible material with exceptional properties that are useful for tissue engineering.Its biodegradability,mechanical robustness,and ability to promote cell growth make it particularly valuable for biomedical applications.Silk fibroin nanomaterials,which comprise silk fibroin processed into nanostructures,offer enhanced surface area,improved loading capacity for bioactive molecules,and superior nanoscale interactions with cells compared with bulk silk fibroin materials.In this study,we first extracted human-derived neural stem cells from a 14-week-old human fetus.Then,neural stem cells were loaded with 1%silk fibroin nanomaterials,which was identified as the optimal concentration to support human-derived neural stem cell growth and release of neurotrophic factors.Finally,1%silk fibroin nanomaterials were implanted into a rat model of hypoxic-ischemic brain injury.The results showed that,compared with the treatment with human-derived neural stem cells alone,silk fibroin hydrogel carrying human-derived neural stem cells was significantly more effective at alleviating brain tissue damage,increasing neurotrophic factor secretion in the brain microenvironment,and promoting motor and cognitive function recovery.These findings suggest that silk fibroin nanomaterials loaded with human-derived neural stem cells could be used to treat hypoxic-ischemic encephalopathy.However,the mechanisms and related signaling pathways by which hydrogels combined with cells exert their reparative effects still require further in-depth investigation.
基金Natural Science Foundation of Beijing,No.7244428(to WZ)Peking University Medicine Sailing Program for Young Scholars’Scientific and Technological Innovation,No.BMU2023YFJHPY034(to WZ)+1 种基金the National Natural Science Foundation of China,Nos.81873784(to DF),82071426(to DF)Clinical Cohort Construction Program of Peking University Third Hospital,Nos.BYSYDL2019002(to DF)and BYSYZD2021004(to DF).
文摘Amyotrophic lateral sclerosis is characterized by the progressive loss of motor neurons.Early-stage axonal dysfunction,rather than central nervous system injury,plays a key role in the disease process.However,the molecular mechanisms underlying this dysfunction remain unclear.To investigate the relationship between peripheral immune dysregulation and axonal dysfunction in amyotrophic lateral sclerosis,we recruited 372 patients within the first 12 months of sporadic amyotrophic lateral sclerosis onset between January 2018 and May 2024.We collected peripheral immune markers at baseline,including total leukocytes,lymphocytes,monocytes,neutrophils,basophils,eosinophils,and platelets.We also calculated four derived ratios:neutrophil-to-lymphocyte ratio,platelet-to-lymphocyte ratio,lymphocyte-to-monocyte ratio,and systemic immune inflammation index.Multivariate analysis,adjusted for confounding factors,revealed that higher counts of total leukocytes and neutrophils,as well as higher neutrophil-related ratios,including the neutrophil to lymphocyte ratio and the systemic immune inflammation index,were significantly correlated with higher compound muscle action potential scores.Stratified analyses revealed that these associations varied by age and sex.Furthermore,mediation analysis demonstrated that axonal dysfunction plays a significant role in the relationship between immune markers and disease progression.These findings emphasize the critical role that peripheral immune dysregulation plays in amyotrophic lateral sclerosis progression by mediating peripheral nerve injury,particularly in the early stages of the disease.This study highlights the importance of the peripheral nervous system in the early stages of amyotrophic lateral sclerosis and provides new insights into disease mechanisms and potential therapeutic targets.
基金supported by the core facility Center for Life Sciences,University of Science and Technology of China,Research Funds of the Center for Advanced Interdisciplinary Science and Biomedicine of IHM(QYZD20220002)the National Natural Science Foundation of China(82071357)the Ministry of Science and Technology of China(2019YFA0405600).
文摘Acute mitochondrial damage and the energy crisis following axonal injury highlight mitochondrial transport as an important target for axonal regeneration.Syntaphilin(Snph),known for its potent mitochondrial anchoring action,has emerged as a significant inhibitor of both mitochondrial transport and axonal regeneration.Therefore,investigating the molecular mechanisms that influence the expression levels of the snph gene can provide a viable strategy to regulate mitochondrial trafficking and enhance axonal regeneration.Here,we reveal the inhibitory effect of microRNA-146b(miR-146b)on the expression of the homologous zebrafish gene syntaphilin b(snphb).Through CRISPR/Cas9 and single-cell electroporation,we elucidated the positive regulatory effect of the miR-146b-snphb axis on Mauthner cell(M-cell)axon regeneration at the global and single-cell levels.Through escape response tests,we show that miR-146b-snphb signaling positively regulates functional recovery after M-cell axon injury.In addition,continuous dynamic imaging in vivo showed that reprogramming miR-146b significantly promotes axonal mitochondrial trafficking in the pre-injury and early stages of regeneration.Our study reveals an intrinsic axonal regeneration regulatory axis that promotes axonal regeneration by reprogramming mitochondrial transport and anchoring.This regulation involves noncoding RNA,and mitochondria-associated genes may provide a potential opportunity for the repair of central nervous system injury.
基金supported by Catalan Government,Nos.2014SGR344(to JT),2017SGR704(to JT),2021SGR01214(to MAL)MCIN/AEI/10.13039/501100011033/by“ERDF A way of making Europe,”Nos.SAF2015-67143(to JT),PID2019-106332GB-I00(to JT and MAL)and PID2022-141252NB-I00(to MAL).
文摘During the development of the nervous system,there is an overproduction of neurons and synapses.Hebbian competition between neighboring nerve endings and synapses performing different activity levels leads to their elimination or strengthening.We have extensively studied the involvement of the brain-derived neurotrophic factor-Tropomyosin-related kinase B receptor neurotrophic retrograde pathway,at the neuromuscular junction,in the axonal development and synapse elimination process versus the synapse consolidation.The purpose of this review is to describe the neurotrophic influence on developmental synapse elimination,in relation to other molecular pathways that we and others have found to regulate this process.In particular,we summarize our published results based on transmitter release analysis and axonal counts to show the different involvement of the presynaptic acetylcholine muscarinic autoreceptors,coupled to downstream serine-threonine protein kinases A and C(PKA and PKC)and voltage-gated calcium channels,at different nerve endings in developmental competition.The dynamic changes that occur simultaneously in several nerve terminals and synapses converge across a postsynaptic site,influence each other,and require careful studies to individualize the mechanisms of specific endings.We describe an activity-dependent balance(related to the extent of transmitter release)between the presynaptic muscarinic subtypes and the neurotrophin-mediated TrkB/p75NTR pathways that can influence the timing and fate of the competitive interactions between the different axon terminals.The downstream displacement of the PKA/PKC activity ratio to lower values,both in competing nerve terminals and at postsynaptic sites,plays a relevant role in controlling the elimination of supernumerary synapses.Finally,calcium entry through L-and P/Q-subtypes of voltage-gated calcium channels(both channels are present,together with the N-type channel in developing nerve terminals)contributes to reduce transmitter release and promote withdrawal of the most unfavorable nerve terminals during elimination(the weakest in acetylcholine release and those that have already become silent).The main findings contribute to a better understanding of punishment-rewarding interactions between nerve endings during development.Identifying the molecular targets and signaling pathways that allow synapse consolidation or withdrawal of synapses in different situations is important for potential therapies in neurodegenerative diseases.
基金supported by the Research Funds of the Center for Advanced Interdisciplinary Science and Biomedicine of IHM,No.QYZD20220002the National Natural Science Foundation of China,No.82071357a grant from the Ministry of Science and Technology of China,No.2019YFA0405600 (all to BH)。
文摘Rab5 is a GTPase protein that is involved in intracellular membrane trafficking. It functions by binding to various effector proteins and regulating cellular responses, including the formation of transport vesicles and their fusion with the cellular membrane. Rab5 has been reported to play an important role in the development of the zebrafish embryo;however, its role in axonal regeneration in the central nervous system remains unclear. In this study, we established a zebrafish Mauthner cell model of axonal injury using single-cell electroporation and two-photon axotomy techniques. We found that overexpression of Rab5 in single Mauthner cells promoted marked axonal regeneration and increased the number of intra-axonal transport vesicles. In contrast, treatment of zebrafish larvae with the Rab kinase inhibitor CID-1067700markedly inhibited axonal regeneration in Mauthner cells. We also found that Rab5 activated phosphatidylinositol 3-kinase(PI3K) during axonal repair of Mauthner cells and promoted the recovery of zebrafish locomotor function. Additionally, rapamycin, an inhibitor of the mechanistic target of rapamycin downstream of PI3K, markedly hindered axonal regeneration. These findings suggest that Rab5 promotes the axonal regeneration of injured zebrafish Mauthner cells by activating the PI3K signaling pathway.
基金supported by the Natio`nal Natural Science Foundation of China,No. 81801241a grant from Sichuan Science and Technology Program,No. 2023NSFSC1578Scientific Research Projects of Southwest Medical University,No. 2022ZD002 (all to JX)。
文摘Neuronal growth, extension, branching, and formation of neural networks are markedly influenced by the extracellular matrix—a complex network composed of proteins and carbohydrates secreted by cells. In addition to providing physical support for cells, the extracellular matrix also conveys critical mechanical stiffness cues. During the development of the nervous system, extracellular matrix stiffness plays a central role in guiding neuronal growth, particularly in the context of axonal extension, which is crucial for the formation of neural networks. In neural tissue engineering, manipulation of biomaterial stiffness is a promising strategy to provide a permissive environment for the repair and regeneration of injured nervous tissue. Recent research has fine-tuned synthetic biomaterials to fabricate scaffolds that closely replicate the stiffness profiles observed in the nervous system. In this review, we highlight the molecular mechanisms by which extracellular matrix stiffness regulates axonal growth and regeneration. We highlight the progress made in the development of stiffness-tunable biomaterials to emulate in vivo extracellular matrix environments, with an emphasis on their application in neural repair and regeneration, along with a discussion of the current limitations and future prospects. The exploration and optimization of the stiffness-tunable biomaterials has the potential to markedly advance the development of neural tissue engineering.
基金supported by grants from Mission Connect, a project of the TIRR Foundation, the Glaucoma Research FoundationNIH grants R01NS112691 and R01NS076708 (to TAW)
文摘Stress signaling following axon injury stimulates a transcriptional program for regeneration that might be exploited to promote central nervous system repair.However,this stress response drives neuronal apoptosis in non-regenerative environments.This duality presents a quandary for the development of therapeutic interventions:manipulating stress signaling to enhance recovery of damaged neurons risks accelerating neurodegeneration or restricting regenerative potential.This dichotomy is well illustrated by the fates of retinal ganglion cells(RGCs)following optic nerve crush.In this central nervous system injury model,disruption of a stress-activated MAP kinase(MAPK)cascade blocks the extensive apoptosis of RGCs that occurs in wild-type mice(Watkins et al.,2013;Welsbie et al.,2017).
基金supported by the National Natural Science Foundation of China,Nos. 81760247, 82171450the Scientific Research Foundation for Doctors of the Affiliated Hospital of Zunyi Medical University,No.(2016)14 (all to HH)。
文摘Current treatments for epilepsy can only manage the symptoms of the condition but cannot alter the initial onset or halt the progression of the disease. Consequently, it is crucial to identify drugs that can target novel cellular and molecular mechanisms and mechanisms of action. Increasing evidence suggests that axon guidance molecules play a role in the structural and functional modifications of neural networks and that the dysregulation of these molecules is associated with epilepsy susceptibility. In this review, we discuss the essential role of axon guidance molecules in neuronal activity in patients with epilepsy as well as the impact of these molecules on synaptic plasticity and brain tissue remodeling. Furthermore, we examine the relationship between axon guidance molecules and neuroinflammation, as well as the structural changes in specific brain regions that contribute to the development of epilepsy. Ample evidence indicates that axon guidance molecules, including semaphorins and ephrins, play a fundamental role in guiding axon growth and the establishment of synaptic connections. Deviations in their expression or function can disrupt neuronal connections, ultimately leading to epileptic seizures. The remodeling of neural networks is a significant characteristic of epilepsy, with axon guidance molecules playing a role in the dynamic reorganization of neural circuits. This, in turn, affects synapse formation and elimination. Dysregulation of these molecules can upset the delicate balance between excitation and inhibition within a neural network, thereby increasing the risk of overexcitation and the development of epilepsy. Inflammatory signals can regulate the expression and function of axon guidance molecules, thus influencing axonal growth, axon orientation, and synaptic plasticity. The dysregulation of neuroinflammation can intensify neuronal dysfunction and contribute to the occurrence of epilepsy. This review delves into the mechanisms associated with the pathogenicity of axon guidance molecules in epilepsy, offering a valuable reference for the exploration of therapeutic targets and presenting a fresh perspective on treatment strategies for this condition.
文摘In this paper, we present a simulation program that allows for the concurrent propagation of action potentials in axons coupled via currents, as well as, for the first time, the computation of the resultant nodal electric field generated as the action potentials traverse the tract of axons. With these fields in hand, we inject currents into nodes of axons that depend on these fields and study the coupling between axons in the presence of the fields and currents present jointly in varying strengths. We find close-to-synchronized propagation in three dimensions. Further, we derive for the first time a mathematical equation for tortuous tracts (as opposed to linear) with such field-mediated coupling. The geometrical formulation enables us to consider spacetime perturbative effects, which have also not been considered in the literature so far. We investigate the case when gravitational radiation is present, in order to determine its impact on tract information processing. We find that action potential relative-timing in a tract is affected by the strength and frequency of gravitational waves and the waning of this influence with weakening strength. This latter study blurs the division between what lies inside and outside man. As an additional novelty, we investigate the influence of geometry on the information transmission capacity of the ephaptically-coupled tract, when viewed as a discrete memoryless channel, and find a rising trend in capacity with increasing axonal inclinations, which may occur in traumatic CNS injury.
基金financially supported by the National Natural Science Foundation of China(No.82474420,No.82273903)。
文摘Objective:Treating peripheral nerve injury(PNI)presents a clinical challenge due to limited axon regeneration.Strychni Semen,a traditional Chinese medicine,is clinically used for numbness and hemiplegia.However,its role in promoting functional recovery after PNI and the related mechanisms have not yet been systematically studied.Methods:A mouse model of sciatic nerve crush(SNC)injury was established and the mice received drug treatment via intragastric gavage,followed by behavioral assessments(adhesive removal test,hot-plate test and Von Frey test).Transcriptomic analyses were performed to examine gene expression in the dorsal root ganglia(DRGs)from the third to the sixth lumbar vertebrae,so as to identify the significantly differentially expressed genes.Immunofluorescence staining was used to assess the expression levels of superior cervical ganglia neural-specific 10 protein(SCG10).The ultra-trace protein detection technique was used to evaluate changes in gene expression levels.Results:Strychni Semen and its active compounds(brucine and strychnine)improved functional recovery in mice following SNC injury.Transcriptomic data indicated that Strychni Semen and its active compounds initiated transcriptional reprogramming that impacted cellular morphology and extracellular matrix remodeling in DRGs after SNC,suggesting potential roles in promoting axon regeneration.Imaging data further confirmed that Strychni Semen and its active compounds facilitated axon regrowth in SNC-injured mice.By integrating protein–protein interaction predictions,ultra-trace protein detection,and molecular docking analysis,we identified myeloperoxidase as a potentially critical factor in the axon regenerative effects conferred by Strychni Semen and its active compounds.Conclusion:Strychni Semen and its active compounds enhance sensory function by promoting axonal regeneration after PNI.These findings establish a foundation for the future applications of Strychni Semen and highlight novel therapeutic strategies and drug targets for axon regeneration.
文摘Erratum to:J Huazhong Univ Sci Technol[Med Sci]36(4):548–553,2016 https://doi.org/10.1007/s11596-016-1623-6 In the originally published article(https://doi.org/10.1007/s11596-016-1623-6),the immunofluorescence images in shRNA group in Fig.3 were accidentally used rather than the final,formal experiments.To retain consistency,the entire Fig.3 is replaced here with original images of the experiments.The authors declare that this correction will not affect the conclusion of the study.
文摘Axonal degeneration is a key pathological feature in many neurological diseases. It often leads to persistent deficits due to the inability of axons to regenerate in the central nervous system. Therefore therapeutic approaches should optimally both attenuate axonal degeneration and foster axonal regeneration. Compelling evidence suggests that collapsin response mediator protein-2（CRMP2） might be a molecular target fulfilling these requirements. In this mini-review, we give a compact overview of the known functions of CRMP2 and its molecular interactors in neurite outgrowth and in neurodegenerative conditions. Moreover, we discuss in detail our recent findings on the role of CRMP2 in acute axonal degeneration in the optic nerve. We found that the calcium influx induced by the lesion activates the protease calpain which cleaves CRMP2, leading to impairment of axonal transport. Both calpain inhibition and CRMP2 overexpression effectively protected the proximal axons against acute axonal degeneration. Taken together, CRMP2 is further characterized as a central molecular player in acute axonal degeneration and thus evolves as a promising therapeutic target to both counteract axonal degeneration and foster axonal regeneration in neurodegenerative and neurotraumatic diseases.
文摘Stroke remains the leading cause of long-term disability.Hemiparesis is one of the most common post-stroke motor deficits and is largely attributed to loss or disruption of the motor signals from the affected motor cortex.As the only direct descending motor pathway,the corticospinal tract(CST)is the primary pathway to innervate spinal motor neurons,and thus,forms the neuroanatomical basis to control the peripheral muscles for voluntary movements.Here,we review evidence from both experimental animals and stroke patients,regarding CST axonal damage,functional contribution of CST axonal integrity and remodeling to neurological recovery,and therapeutic approaches aimed to enhance CST axonal remodeling after stroke.The new insights gleaned from preclinical and clinical studies may encourage the development of more rational therapeutics with a strategy targeted to promote axonal rewiring for corticospinal innervation,which will significantly impact the current clinical needs of subacute and chronic stroke treatment.
基金This work was supported by the Muscular Dystrophy Association,No.W81XWH1910229(to MHF)from Department of Defense’s Congressionally Directed Medical Research Program,and Maryland Stem Cell Research Fund,No.2019-MSCRFD-5093(to MHF).
文摘Nervous system disorders are prevalent health issues that will only continue to increase in frequency as the population ages.Dying-back axonopathy is a hallmark of many neurologic diseases and leads to axonal disconnection from their targets,which in turn leads to functional impairment.During the course of many of neurologic diseases,axons can regenerate or sprout in an attempt to reconnect with the target and restore synapse function.In amyotrophic lateral sclerosis(ALS),distal motor axons retract from neuromuscular junctions early in the disease-course before significant motor neuron death.There is evidence of compensatory motor axon sprouting and reinnervation of neuromuscular junctions in ALS that is usually quickly overtaken by the disease course.Potential drugs that enhance compensatory sprouting and encourage reinnervation may slow symptom progression and retain muscle function for a longer period of time in ALS and in other diseases that exhibit dying-back axonopathy.There remain many outstanding questions as to the impact of distinct disease-causing mutations on axonal outgrowth and regeneration,especially in regards to motor neurons derived from patient induced pluripotent stem cells.Compartmentalized microfluidic chambers are powerful tools for studying the distal axons of human induced pluripotent stem cells-derived motor neurons,and have recently been used to demonstrate striking regeneration defects in human motor neurons harboring ALS disease-causing mutations.Modeling the human neuromuscular circuit with human induced pluripotent stem cells-derived motor neurons will be critical for developing drugs that enhance axonal regeneration,sprouting,and reinnervation of neuromuscular junctions.In this review we will discuss compensatory axonal sprouting as a potential therapeutic target for ALS,and the use of compartmentalized microfluidic devices to find drugs that enhance regeneration and axonal sprouting of motor axons.
