Previous studies have shown that the receptor tyrosine kinase Eph receptor A4(EphA4) is abundantly expressed in the nervous system. The EphA4 signaling pathway plays an important role in regulating motor neuron ferrop...Previous studies have shown that the receptor tyrosine kinase Eph receptor A4(EphA4) is abundantly expressed in the nervous system. The EphA4 signaling pathway plays an important role in regulating motor neuron ferroptosis in motor neuron disease. To investigate whether EphA4 signaling is involved in ferroptosis in spinal cord ischemia/reperfusion injury, in this study we established a rat model of spinal cord ischemia/reperfusion injury by clamping the left carotid artery and the left subclavian artery. We found that spinal cord ischemia/reperfusion injury increased EphA4 expression in the neurons of anterior horn, markedly worsened ferroptosis-related indicators, substantially increased the number of mitochondria exhibiting features consistent with ferroptosis, promoted deterioration of motor nerve function, increased the permeability of the blood-spinal cord barrier, and increased the rate of motor neuron death. Inhibition of EphA4 largely rescued these effects. However, intrathecal administration of the ferroptosis inducer Erastin counteracted the beneficial effects conferred by treatment with the EphA4 inhibitor. Mass spectrometry and a PubMed search were performed to identify proteins that interact with EphA4, with the most notable being Beclin1 and Erk1/2. Our results showed that inhibition of EphA4 expression reduced binding to Beclin1, markedly reduced p-Beclin1, and reduced Beclin1-XCT complex formation. Inhibition of EphA4 also reduced binding to p-Erk1/2 and markedly decreased the expression of c-Myc, transferrin receptor 1, and p-Erk1/2. Additionally, we observed co-localization of EphA4 and p-Beclin1 and of EphA4 and p-ERK1/2 in neurons in the anterior horn. In conclusion, EphA4 participates in regulating ferroptosis of spinal motor neurons in the anterior horn in spinal cord ischemia/reperfusion injury by promoting formation of the Beclin1-XCT complex and activating the Erk1/2/c-Myc/transferrin receptor 1 axis.展开更多
Protective effect of interleukin 1β (IL 1β) on motor neurons was studied after peripheral nerve injury. Twenty Wistar rats were divided into 2 groups randomly. The right sciatic nerve of each rat was resected. Aft...Protective effect of interleukin 1β (IL 1β) on motor neurons was studied after peripheral nerve injury. Twenty Wistar rats were divided into 2 groups randomly. The right sciatic nerve of each rat was resected. After silicon tubulization of sciatic nerve in rat, 15 μl 1 ng/ml IL 1β and PBS solution were injected into the silicon capsule respectively. Enzyme histochemistry was performed to show acetyle cholesterase (AchE) and nitric oxide staining (NOS) activity of spinal α motor neurons in spinal segments 2 weeks later. Neurons were counted and the diameter and cross sectional (c/s) area of neurons were analyzed by using computer image analysis system. The results showed that as compared with the normal side, both enzyme activities significantly changed in motor neurons in PBS group. The diameter and c/s area of both neurons changed significantly too ( P< 0 01). These results suggest that exogenous IL 1β protects α motor neurons from degeneration and necrosis after peripheral nerve injury.展开更多
Amyotrophic lateral sclerosis is the most common adult-onset neurodegenerative disease affecting motor neurons. Its defining feature is progressive loss of motor neuron function in the cortex, brainstem, and spinal co...Amyotrophic lateral sclerosis is the most common adult-onset neurodegenerative disease affecting motor neurons. Its defining feature is progressive loss of motor neuron function in the cortex, brainstem, and spinal cord, leading to paralysis and death. Despite major advances in identifying genes that can cause disease when mutated and model the disease in animals and cellular models, it still remains unclear why motor symptoms suddenly appear after a long pre-symptomatic phase of apparently normal function. One hypothesis is that age-related deregulation of specific proteins within key cell types, especially motor neurons themselves, initiates disease symptom appearance and may also drive progressive degeneration. Genome-wide in vivo cell-type-specific screening tools are enabling identification of candidates for such proteins. In this minireview, we first briefly discuss the methodology used in a recent study that applied a motor neuron-specific RNASeq screening approach to a standard model of TAR DNA-binding protein-43(TDP-43)-driven amyotrophic lateral sclerosis. A key finding of this study is that synaptogyrin-4 and pleckstrin homology domain-containing family B member 1 are also deregulated at the protein level within motor neurons of two unrelated mouse models of mutant TDP-43 driven amyotrophic lateral sclerosis. Guided by what is known about molecular and cellular functions of these proteins and their orthologs, we outline here specific hypotheses for how changes in their levels might potentially alter cellular physiology of motor neurons and detrimentally affect motor neuron function. Where possible, we also discuss how this information could potentially be used in a translational context to develop new therapeutic strategies for this currently incurable, devastating disease.展开更多
Amyotrophic lateral sclerosis （ALS） is a fatal progressive disorder characterized by the selective degeneration of motor neurons （MN）. The impact of peripheral immune status on disease progression and MN survival ...Amyotrophic lateral sclerosis （ALS） is a fatal progressive disorder characterized by the selective degeneration of motor neurons （MN）. The impact of peripheral immune status on disease progression and MN survival is becoming increasingly recognized in the ALS research field. In this review, we briefly discuss findings from mouse models of peripheral nerve injury and immunodeficiency to understand how the immune system regulates MN survival. We extend these observations to similar studies in the widely used superoxide dismutase 1 （SOD1） mouse model of ALS. Last, we present future hypotheses to identify potential causative factors that lead to immune dysregulation in ALS. The lessons from preceding work in this area offer new exciting directions to bridge the gap in our current understanding of immune mediated neuroprotection in ALS.展开更多
We report a 50-year-old woman who developed localized proximal muscle weakness, in addition to transient elevation of antibodies to GM-1 ganglioside, without multifocal conduction block. She was treated with intraveno...We report a 50-year-old woman who developed localized proximal muscle weakness, in addition to transient elevation of antibodies to GM-1 ganglioside, without multifocal conduction block. She was treated with intravenous immunoglobulin (IVIg) and steroid pulse therapy, which were effective for over 10 years. Her clinical course and laboratory tests were consistent with lower motor neuron syndrome (LMNS) with localized proximal muscle weakness. We suggest that some patients diagnosed as LMNS may remain responsive to IVIg or steroid pulse therapy for a long time.展开更多
Brachial plexus avulsion often results in massive motor neuron death and severe functional deficits of target muscles. However, no satisfactory treatment is currently available. Hypoxia-inducible factor 1α is a criti...Brachial plexus avulsion often results in massive motor neuron death and severe functional deficits of target muscles. However, no satisfactory treatment is currently available. Hypoxia-inducible factor 1α is a critical molecule targeting several genes associated with ischemia-hypoxia damage and angiogenesis. In this study, a rat model of brachial plexus avulsion-reimplantation was established, in which C5–7 ventral nerve roots were avulsed and only the C6 root reimplanted. Different implants were immediately injected using a microsyringe into the avulsion-reimplantation site of the C6 root post-brachial plexus avulsion. Rats were randomly divided into five groups: phosphate-buffered saline, negative control of lentivirus, hypoxia-inducible factor 1α(hypoxia-inducible factor 1α overexpression lentivirus), gel(pluronic F-127 hydrogel), and gel + hypoxia-inducible factor 1α(pluronic F-127 hydrogel + hypoxia-inducible factor 1α overexpression lentivirus). The Terzis grooming test was performed to assess recovery of motor function. Scores were higher in the hypoxia-inducible factor 1α and gel +hypoxia-inducible factor 1α groups(in particular the gel + hypoxia-inducible factor 1α group) compared with the phosphate-buffered saline group. Electrophysiology, fluorogold retrograde tracing, and immunofluorescent staining were further performed to investigate neural pathway reconstruction and changes of neurons, motor endplates, and angiogenesis. Compared with the phosphate-buffered saline group, action potential latency of musculocutaneous nerves was markedly shortened in the hypoxia-inducible factor 1α and gel + hypoxia-inducible factor1α groups. Meanwhile, the number of fluorogold-positive cells and ChAT-positive neurons, neovascular area(labeled by CD31 around av ulsed sites in ipsilateral spinal cord segments), and the number of motor endplates in biceps brachii(identified by α-bungarotoxin) were all visibly increased, as well as the morphology of motor endplate in biceps brachil was clear in the hypoxia-inducible factor 1α and gel + hypoxia-inducible factor 1α groups. Taken together, delivery of hypoxia-inducible factor 1α overexpression lentiviral vectors mediated by pluronic F-127 effectively promotes spinal root regeneration and functional recovery post-brachial plexus avulsion. All animal procedures were approved by the Institutional Animal Care and Use Committee of Guangdong Medical University, China.展开更多
Spinal muscular atrophy(SMA)is a rare hereditary neuromuscular disease with a high lethality rate in infants.Variants in the homologous genes survival of motor neuron(SMN)1 and SMN2 have been reported to be SMA pathog...Spinal muscular atrophy(SMA)is a rare hereditary neuromuscular disease with a high lethality rate in infants.Variants in the homologous genes survival of motor neuron(SMN)1 and SMN2 have been reported to be SMA pathogenic factors.Previous studies showed that a highinclusion rate of SMN2 exon 7 increased SMN expression,which in turn reduced the severity of SMA.The inclusion rate of SMN2 exon 7 was higher in neural tissues than in non-neural tissues.Neuro-oncological ventral antigen(NOVA)is a splicing factor that is specifically and highly expressed in neurons.It plays a key role in nervous system development and in the induction of nervous system diseases.Howeve r,it remains unclear whether this splicing factor affects SMA.In this study,we analyzed the inclusion of SMN2 exon 7 in different tissues in a mouse model of SMA(genotype smn^(-/-)SMN2^(2 tg/0))and litter mate controls(genotype smn^(+/-)SMN2^(2 tg/0)).We found that inclusion level of SMN2 exon 7 was high in the brain and spinal co rd tissue,and that NOVA1 was also highly expressed in nervous system tissues.In addition,SMN2 exon 7 and NOVA1 were expressed synchronously in the central nervous system.We further investigated the effects of NOVA1 on disease and found that the number of neurons in the anterior horn of spinal cord decreased in the mouse model of SMA during postnatal days 1-7,and that NOVA1 expression levels in motor neurons decreased simultaneously as spinal muscular atrophy developed.We also found that in vitro expression of NOVA1 increased the inclusion of SMN2 exon 7 and expression ofthe SMN2 protein in the U87 MG cell line,whereas the opposite was observed when NOVA1 was knocked down.Finally,point mutation and RNA pull-down showed that the UCAC motif in SMN2 exon 7 plays a critical role in NOVA1 binding and promoting the inclusion of exon 7.Moreove r,CA was more essential for the inclusion of exon 7 than the order of Y residues in the motif.Collectively,these findings indicate that NOVA1 intera cts with the UCAC motif in exon 7 of SMN2,there by enhancing inclusion of exon 7 in SMN2,which in turn increases expression of the SMN protein.展开更多
基金supported by the National Natural Science Foundation of China,No.81771342 (to HM)。
文摘Previous studies have shown that the receptor tyrosine kinase Eph receptor A4(EphA4) is abundantly expressed in the nervous system. The EphA4 signaling pathway plays an important role in regulating motor neuron ferroptosis in motor neuron disease. To investigate whether EphA4 signaling is involved in ferroptosis in spinal cord ischemia/reperfusion injury, in this study we established a rat model of spinal cord ischemia/reperfusion injury by clamping the left carotid artery and the left subclavian artery. We found that spinal cord ischemia/reperfusion injury increased EphA4 expression in the neurons of anterior horn, markedly worsened ferroptosis-related indicators, substantially increased the number of mitochondria exhibiting features consistent with ferroptosis, promoted deterioration of motor nerve function, increased the permeability of the blood-spinal cord barrier, and increased the rate of motor neuron death. Inhibition of EphA4 largely rescued these effects. However, intrathecal administration of the ferroptosis inducer Erastin counteracted the beneficial effects conferred by treatment with the EphA4 inhibitor. Mass spectrometry and a PubMed search were performed to identify proteins that interact with EphA4, with the most notable being Beclin1 and Erk1/2. Our results showed that inhibition of EphA4 expression reduced binding to Beclin1, markedly reduced p-Beclin1, and reduced Beclin1-XCT complex formation. Inhibition of EphA4 also reduced binding to p-Erk1/2 and markedly decreased the expression of c-Myc, transferrin receptor 1, and p-Erk1/2. Additionally, we observed co-localization of EphA4 and p-Beclin1 and of EphA4 and p-ERK1/2 in neurons in the anterior horn. In conclusion, EphA4 participates in regulating ferroptosis of spinal motor neurons in the anterior horn in spinal cord ischemia/reperfusion injury by promoting formation of the Beclin1-XCT complex and activating the Erk1/2/c-Myc/transferrin receptor 1 axis.
文摘Protective effect of interleukin 1β (IL 1β) on motor neurons was studied after peripheral nerve injury. Twenty Wistar rats were divided into 2 groups randomly. The right sciatic nerve of each rat was resected. After silicon tubulization of sciatic nerve in rat, 15 μl 1 ng/ml IL 1β and PBS solution were injected into the silicon capsule respectively. Enzyme histochemistry was performed to show acetyle cholesterase (AchE) and nitric oxide staining (NOS) activity of spinal α motor neurons in spinal segments 2 weeks later. Neurons were counted and the diameter and cross sectional (c/s) area of neurons were analyzed by using computer image analysis system. The results showed that as compared with the normal side, both enzyme activities significantly changed in motor neurons in PBS group. The diameter and c/s area of both neurons changed significantly too ( P< 0 01). These results suggest that exogenous IL 1β protects α motor neurons from degeneration and necrosis after peripheral nerve injury.
基金supported in part by funding from the Else Kr?ner Fresenius Stiftung(Co-PI)the Werner Otto Stiftung(PI)(to KED)。
文摘Amyotrophic lateral sclerosis is the most common adult-onset neurodegenerative disease affecting motor neurons. Its defining feature is progressive loss of motor neuron function in the cortex, brainstem, and spinal cord, leading to paralysis and death. Despite major advances in identifying genes that can cause disease when mutated and model the disease in animals and cellular models, it still remains unclear why motor symptoms suddenly appear after a long pre-symptomatic phase of apparently normal function. One hypothesis is that age-related deregulation of specific proteins within key cell types, especially motor neurons themselves, initiates disease symptom appearance and may also drive progressive degeneration. Genome-wide in vivo cell-type-specific screening tools are enabling identification of candidates for such proteins. In this minireview, we first briefly discuss the methodology used in a recent study that applied a motor neuron-specific RNASeq screening approach to a standard model of TAR DNA-binding protein-43(TDP-43)-driven amyotrophic lateral sclerosis. A key finding of this study is that synaptogyrin-4 and pleckstrin homology domain-containing family B member 1 are also deregulated at the protein level within motor neurons of two unrelated mouse models of mutant TDP-43 driven amyotrophic lateral sclerosis. Guided by what is known about molecular and cellular functions of these proteins and their orthologs, we outline here specific hypotheses for how changes in their levels might potentially alter cellular physiology of motor neurons and detrimentally affect motor neuron function. Where possible, we also discuss how this information could potentially be used in a translational context to develop new therapeutic strategies for this currently incurable, devastating disease.
基金supported by grants from NIH/NINDS R01 funding NS40433
文摘Amyotrophic lateral sclerosis （ALS） is a fatal progressive disorder characterized by the selective degeneration of motor neurons （MN）. The impact of peripheral immune status on disease progression and MN survival is becoming increasingly recognized in the ALS research field. In this review, we briefly discuss findings from mouse models of peripheral nerve injury and immunodeficiency to understand how the immune system regulates MN survival. We extend these observations to similar studies in the widely used superoxide dismutase 1 （SOD1） mouse model of ALS. Last, we present future hypotheses to identify potential causative factors that lead to immune dysregulation in ALS. The lessons from preceding work in this area offer new exciting directions to bridge the gap in our current understanding of immune mediated neuroprotection in ALS.
文摘We report a 50-year-old woman who developed localized proximal muscle weakness, in addition to transient elevation of antibodies to GM-1 ganglioside, without multifocal conduction block. She was treated with intravenous immunoglobulin (IVIg) and steroid pulse therapy, which were effective for over 10 years. Her clinical course and laboratory tests were consistent with lower motor neuron syndrome (LMNS) with localized proximal muscle weakness. We suggest that some patients diagnosed as LMNS may remain responsive to IVIg or steroid pulse therapy for a long time.
基金financially supported by the National Natural Science Foundation of China,No.81371366(to HFW)the Natural Science Foundation of Guangdong Province of China,No.2015A030313515(to HFW)+1 种基金the Dongguan International Science and Technology Cooperation Project,No.2013508152010(to HFW)the Key Project of Social Development of Dongguan of China,No.20185071521640(to HFW)
文摘Brachial plexus avulsion often results in massive motor neuron death and severe functional deficits of target muscles. However, no satisfactory treatment is currently available. Hypoxia-inducible factor 1α is a critical molecule targeting several genes associated with ischemia-hypoxia damage and angiogenesis. In this study, a rat model of brachial plexus avulsion-reimplantation was established, in which C5–7 ventral nerve roots were avulsed and only the C6 root reimplanted. Different implants were immediately injected using a microsyringe into the avulsion-reimplantation site of the C6 root post-brachial plexus avulsion. Rats were randomly divided into five groups: phosphate-buffered saline, negative control of lentivirus, hypoxia-inducible factor 1α(hypoxia-inducible factor 1α overexpression lentivirus), gel(pluronic F-127 hydrogel), and gel + hypoxia-inducible factor 1α(pluronic F-127 hydrogel + hypoxia-inducible factor 1α overexpression lentivirus). The Terzis grooming test was performed to assess recovery of motor function. Scores were higher in the hypoxia-inducible factor 1α and gel +hypoxia-inducible factor 1α groups(in particular the gel + hypoxia-inducible factor 1α group) compared with the phosphate-buffered saline group. Electrophysiology, fluorogold retrograde tracing, and immunofluorescent staining were further performed to investigate neural pathway reconstruction and changes of neurons, motor endplates, and angiogenesis. Compared with the phosphate-buffered saline group, action potential latency of musculocutaneous nerves was markedly shortened in the hypoxia-inducible factor 1α and gel + hypoxia-inducible factor1α groups. Meanwhile, the number of fluorogold-positive cells and ChAT-positive neurons, neovascular area(labeled by CD31 around av ulsed sites in ipsilateral spinal cord segments), and the number of motor endplates in biceps brachii(identified by α-bungarotoxin) were all visibly increased, as well as the morphology of motor endplate in biceps brachil was clear in the hypoxia-inducible factor 1α and gel + hypoxia-inducible factor 1α groups. Taken together, delivery of hypoxia-inducible factor 1α overexpression lentiviral vectors mediated by pluronic F-127 effectively promotes spinal root regeneration and functional recovery post-brachial plexus avulsion. All animal procedures were approved by the Institutional Animal Care and Use Committee of Guangdong Medical University, China.
基金the National Natural Science Foundation of China,No.32000841(to JJS)a grant from Science and Technology Project of Nantong of Jiangsu Province,No.JC2018090(to LCW)a grant from Graduate Research and Innovation Project of Jiangsu Province,No.KYCX18-2415(to LLD)。
文摘Spinal muscular atrophy(SMA)is a rare hereditary neuromuscular disease with a high lethality rate in infants.Variants in the homologous genes survival of motor neuron(SMN)1 and SMN2 have been reported to be SMA pathogenic factors.Previous studies showed that a highinclusion rate of SMN2 exon 7 increased SMN expression,which in turn reduced the severity of SMA.The inclusion rate of SMN2 exon 7 was higher in neural tissues than in non-neural tissues.Neuro-oncological ventral antigen(NOVA)is a splicing factor that is specifically and highly expressed in neurons.It plays a key role in nervous system development and in the induction of nervous system diseases.Howeve r,it remains unclear whether this splicing factor affects SMA.In this study,we analyzed the inclusion of SMN2 exon 7 in different tissues in a mouse model of SMA(genotype smn^(-/-)SMN2^(2 tg/0))and litter mate controls(genotype smn^(+/-)SMN2^(2 tg/0)).We found that inclusion level of SMN2 exon 7 was high in the brain and spinal co rd tissue,and that NOVA1 was also highly expressed in nervous system tissues.In addition,SMN2 exon 7 and NOVA1 were expressed synchronously in the central nervous system.We further investigated the effects of NOVA1 on disease and found that the number of neurons in the anterior horn of spinal cord decreased in the mouse model of SMA during postnatal days 1-7,and that NOVA1 expression levels in motor neurons decreased simultaneously as spinal muscular atrophy developed.We also found that in vitro expression of NOVA1 increased the inclusion of SMN2 exon 7 and expression ofthe SMN2 protein in the U87 MG cell line,whereas the opposite was observed when NOVA1 was knocked down.Finally,point mutation and RNA pull-down showed that the UCAC motif in SMN2 exon 7 plays a critical role in NOVA1 binding and promoting the inclusion of exon 7.Moreove r,CA was more essential for the inclusion of exon 7 than the order of Y residues in the motif.Collectively,these findings indicate that NOVA1 intera cts with the UCAC motif in exon 7 of SMN2,there by enhancing inclusion of exon 7 in SMN2,which in turn increases expression of the SMN protein.
