Soybean oleic acid content is one of the important indexes to evaluate the quality of soybean oil.In the synthesis pathway of soybean fatty acids,the FAD2 gene family is the key gene that regulates the production of l...Soybean oleic acid content is one of the important indexes to evaluate the quality of soybean oil.In the synthesis pathway of soybean fatty acids,the FAD2 gene family is the key gene that regulates the production of linoleic acid from soybean oleic acid.In this study,CRISPR/Cas9 gene editing technology was used to regulate FAD2 gene expression.Firstly,the CRISPR/Cas9 single knockout vectors GmFAD2-1B and GmFAD2-2C and double knockout vectors GmFAD2-2A-3 were constructed.Then,the three vectors were transferred into the recipient soybean variety Jinong 38 by Agrobacterium-mediated cotyledon node transformation,and the mutant plants were obtained.Functional analysis and comparison of the mutant plants of the T2 and T3 generations were carried out.The results showed that there was no significant difference in agronomic traits between the CRISPR/Cas9 single and double knockout vectors and the untransformed CRISPR/Cas9 receptor varieties.The oleic acid content of the plants that knocked out the CRISPR/Cas9 double gene vector was significantly higher than that of the single gene vector.展开更多
Recent advances have witnessed the success and popularity of cloud computing, which represents a new business model and computing paradigm. The feature of on-demand provisioning of computational, storage, and bandwidt...Recent advances have witnessed the success and popularity of cloud computing, which represents a new business model and computing paradigm. The feature of on-demand provisioning of computational, storage, and bandwidth resources has driven modern businesses into cloud services. The cloud is considered cutting edge technology and it is solely relied on by many large technology, business, and media companies such as Netflix or Salesforce.com. However, in addition to the benefit at hand, security issues have been a long-term concern for cloud computing and are the main barriers of the widespread use of cloud computing. In this paper, we briefly describe some basic security concerns that are of particular interest to cloud technology. We investigate some of the basic cloud concepts and discuss cloud security issues. Amazon Web Services is used as a case study for discussing common cloud terminology. Data security, as well as some cloud specific attacks is introduced. The current state and the future progression of cloud computing is discussed.展开更多
Dye molecules often change colors(so-called “chromism”) according to the environment variation. However, they are rarely induced by a catalytic amount of cavity. Through encapsulation in the cavity of a porous coord...Dye molecules often change colors(so-called “chromism”) according to the environment variation. However, they are rarely induced by a catalytic amount of cavity. Through encapsulation in the cavity of a porous coordination cage(PCC-2), Rhodamine B(1) is transformed from red quinonoid form(1q) into colorless lactone form(1l) in aprotic polar solutions. The μ4-OH groups in the cavity of PCC-2 are shown to stabilize the uncommon zwitterion intermediate(1z), followed by converting to 1l, thus accelerating the equilibrium. The chromism is catalyzed by 0.25 mol% of PCC-2, and the reaction rate is improved by 80,400times. 1@PCC-2 can be further fabricated to a sol-gel that exhibits ion recognition properties. The resulting encapsulation and stabilization of an unconventional intermediate by a catalytic amount of the coordination cage provides fundamental insights into molecular isomerization and has potential use in chemical sensing.展开更多
Transplanting human neural progenitor cells is a promising method of replenishing the lost neurons after spinal cord injury (SCI), but differentiating neural progenitor cells into the diverse types of mature functiona...Transplanting human neural progenitor cells is a promising method of replenishing the lost neurons after spinal cord injury (SCI), but differentiating neural progenitor cells into the diverse types of mature functional spinal cord neurons in vivo is challenging. In this study, engineered human embryonic spinal cord-like tissues with dorsal and ventral neuronal characters (DV-SC) were generated by inducing human neural progenitor cells (hscNPCs) to differentiate into various types of dorsal and ventral neuronal cells on collagen scaffold in vitro. Transplantation of DV-SC into complete SCI models in rats and monkeys showed better therapeutic effects than undifferentiated hscNPCs, including pronounced cell survival and maturation. DV-SC formed a targeted connection with the host’s ascending and descending axons, partially restored interrupted neural circuits, and improved motor evoked potentials and the hindlimb function of animals with SCI. This suggests that the transplantation of pre-differentiated hscNPCs with spinal cord dorsal and ventral neuronal characteristics could be a promising strategy for SCI repair.展开更多
Neural stem progenitor cell(NSPC)transplantation has been regarded as a promising therapeutic method for spinal cord injury(SCI)repair.However,different NSPCs may have different therapeutic effects,and it is therefore...Neural stem progenitor cell(NSPC)transplantation has been regarded as a promising therapeutic method for spinal cord injury(SCI)repair.However,different NSPCs may have different therapeutic effects,and it is therefore important to identify the optimal NSPC type.In our study,we compared the transcriptomes of human fetal brain-derived NSPCs(BNSPCs),spinal cord-derived NSPCs(SCNSPCs)and H9 embryonic stem-cell derived NSPCs(H9-NSPCs)in vitro and subsequently we transplanted each NSPC type on a collagen scaffold into a T8-9 complete SCI rat model in vivo.In vitro data showed that SCNSPCs had more highly expressed genes involved in nerve-related functions than the other two cell types.In vivo,compared with BNSPCs and H9-NSPCs,SCNSPCs exhibited the best therapeutic effects;in fact,SCNSPCs facilitated electrophysiological and hindlimb functional recovery.This study demonstrates that SCNSPCs may be an appropriate candidate cell type for SCI repair,which is of great clinical significance.展开更多
The objective of this clinical study was to assess the safety and feasibility of the collagen scaffold, Neuro Regen scaffold, one year after scar tissue resection and implantation. Scar tissue is a physical and chemic...The objective of this clinical study was to assess the safety and feasibility of the collagen scaffold, Neuro Regen scaffold, one year after scar tissue resection and implantation. Scar tissue is a physical and chemical barrier that prevents neural regeneration. However, identification of scar tissue is still a major challenge. In this study, the nerve electrophysiology method was used to distinguish scar tissue from normal neural tissue, and then different lengths of scars ranging from 0.5–4.5 cm were surgically resected in five complete chronic spinal cord injury(SCI) patients. The NeuroR egen scaffold along with autologous bone marrow mononuclear cells(BMMCs), which have been proven to promote neural regeneration and SCI recovery in animal models, were transplanted into the gap in the spinal cord following scar tissue resection. No obvious adverse effects related to scar resection or Neuro Regen scaffold transplantation were observed immediately after surgery or at the 12-month follow-up. In addition, patients showed partially autonomic nervous function improvement, and the recovery of somatosensory evoked potentials(SSEP) from the lower limbs was also detected. The results indicate that scar resection and Neuro Regen scaffold transplantation could be a promising clinical approach to treating SCI.展开更多
A method of multi-block Single Shot Multi Box Detector(SSD)based on small object detection is proposed to the railway scene of unmanned aerial vehicle surveillance.To address the limitation of small object detection,a...A method of multi-block Single Shot Multi Box Detector(SSD)based on small object detection is proposed to the railway scene of unmanned aerial vehicle surveillance.To address the limitation of small object detection,a multi-block SSD mechanism,which consists of three steps,is designed.First,the original input images are segmented into several overlapped patches.Second,each patch is separately fed into an SSD to detect the objects.Third,the patches are merged together through two stages.In the first stage,the truncated object of the sub-layer detection result is spliced.In the second stage,a sub-layer suppression and filtering algorithm applying the concept of non-maximum suppression is utilized to remove the overlapped boxes of sub-layers.The boxes that are not detected in the main-layer are retained.In addition,no sufficient labeled training samples of railway circumstance are available,thereby hindering the deployment of SSD.A two-stage training strategy leveraging to transfer learning is adopted to solve this issue.The deep learning model is preliminarily trained using labeled data of numerous auxiliaries,and then it is refined using only a few samples of railway scene.A railway spot in China,which is easily damaged by landslides,is investigated as a case study.Experimental results show that the proposed multi-block SSD method produces an overall accuracy of 96.6%and obtains an improvement of up to 9.2%compared with the traditional SSD.展开更多
Traumatic spinal cord injury(SCI) is a major challenge in the clinic. In this study, we sought to examine the synergistic effects of linear ordered collagen scaffold(LOCS) and human placenta-derived mesenchymal stem c...Traumatic spinal cord injury(SCI) is a major challenge in the clinic. In this study, we sought to examine the synergistic effects of linear ordered collagen scaffold(LOCS) and human placenta-derived mesenchymal stem cells(hPMSCs) when transplanted into completely transected beagle dogs. After 36 weeks observation, we found that LOCS+hPMSCs implants promoted better hindlimb locomotor recovery than was observed in the non-treatment(control) group and LOCS group. Histological analysis showed that the regenerated tissue after treatment was well integrated with the host tissue, and dramatically reduced the volume of cystic and chondroitin sulfate proteoglycans(CSPGs) expression. Furthermore, the LOCS+hPMSCs group also showed more neuron-specific βIII-tubulin(Tuj-1)-and NeuN-positive neurons in the lesion area, as well as axonal regeneration, remyelination and synapse formation in the lesion site. Additionally, dogs in the LOCS+hPMSCs group experienced enhanced sprouting of both ascending(CGRP-positive) sensory fibers and descending(5-HT-and TH-positive) motor fibers at the lesion area. All these data together suggested that the combined treatment had beneficial effects on neuronal regeneration and functional improvement in a canine complete transection model. Therefore, LOCS+hPMSCs implantation holds a great promise for bridging the nerve defect and may be clinically useful in the near future.展开更多
Traumatic spinal cord injury (SCI) usually results in devastating neurologic deficits and disability. In the United States,approximately 12,500 new cases are reported each year, while an estimated 100,000–140,000 new...Traumatic spinal cord injury (SCI) usually results in devastating neurologic deficits and disability. In the United States,approximately 12,500 new cases are reported each year, while an estimated 100,000–140,000 new cases occur every year in China (National Spinal Cord Injury Statistical Center, 2016).Spinal cord injuries are highly disabling and primarily affect young adults, and therefore create great psychological and financial burden on the affected individuals and their families.展开更多
Grafted embryonic central neural tissue pieces can recover function of hemisected spinal cord in neonatal rats and promote axonal growth in adults. However, spinal cord segments from adults have not been used as donor...Grafted embryonic central neural tissue pieces can recover function of hemisected spinal cord in neonatal rats and promote axonal growth in adults. However, spinal cord segments from adults have not been used as donor segments for allogeneic transplantation. Here, we utilized adult spinal cord tissue grafts(aSCGs) as donor constructs for repairing complete spinal cord injury(SCI). Moreover, to provide a favourable microenvironment for SCI treatment, a growth factor cocktail containing three growth factors(brain-derived neurotrophic factor, neurotrophin-3 and vascular endothelial growth factor), was applied to the aSCG transplants. We found that the locomotor function was significantly improved 12 weeks after transplantation of aSCGs into the spinal cord lesion site in adult rats. Transplantation of aSCGs combined with these growth factors enhanced neuron and oligodendrocyte survival and functional restoration. These encouraging results indicate that treatment of complete SCI by transplanting aSCGs, especially in the presence of growth factors, has a positive effect on motor functional recovery, and therefore could be considered as a possible therapeutic strategy for SCI.展开更多
Mesenchymal stem cells (MSCs) show the great promise for the treatment of a variety of diseases because of their self-renewal and multipotential abilities. MSCs are generally cultured on two-dimensional (2D) subst...Mesenchymal stem cells (MSCs) show the great promise for the treatment of a variety of diseases because of their self-renewal and multipotential abilities. MSCs are generally cultured on two-dimensional (2D) substrate in vitro. There are indications that they may simultaneously lose their sternness and multipotentiality as the result of prolonged 2D culture. In this study, we used three-dimensional (3D) collagen scaffolds as rat MSCs cartier and compared the properties of MSCs on 3D collagen scaffolds with monolayer cultured MSCs. The results demonstrated that collagen scaffolds were suitable for rat MSCs adherence and proliferation. More importantly, compared to MSCs under 2D culture, 3D MSCs significantly maintained higher expression levels of stemness genes (Oct4, Sox2, Rex-1 and Nanog), yielded high frequencies of colony-forming units-fibroblastic (CFU-F) and showed enhanced osteogenic and adipogenic differentiation efficiency upon induction. Thus, 3D collagen scaffolds may be beneficial for expanding rat MSCs while maintaining the stem cell properties in vitro.展开更多
OCT4 is one of the key transcription factors in maintaining the pluripotency and self-renewal of embryonic stem (ES) cells.Human OCT4 can generate two isoforms OCT4A and OCT4B by alternative splicing.OCT4B1 is a rec...OCT4 is one of the key transcription factors in maintaining the pluripotency and self-renewal of embryonic stem (ES) cells.Human OCT4 can generate two isoforms OCT4A and OCT4B by alternative splicing.OCT4B1 is a recently discovered novel OCT4 spliced variant,which has been considered as a putative marker of stemness.Compared with the OCT4B mRNA,OCT4B1 mRNA is generated by retaining intron 2 as a cryptic exon which contains a TGA stop codon in it.As a result,the protein product of OCT4B1 mRNA could be truncated.Interestingly,we present here that OCT4B1 can indirectly produce the same protein products as OCT4B.We have demonstrated that OCT4B1 mRNA can be spliced into OCT4B mRNA,and encode three protein isoforms.The splicing of OCT4B1 mRNA into OCT4B mRNA can be remarkably inhibited by the mutation of the classical splicing site.Our result suggests that OCT4B mRNA may originate from OCT4B1 mRNA by alternative splicing.展开更多
Spinal cord injury(SCI)often results in an inhibitory environment at the injury site.In our previous studies,transplantation of a scaffold combined with stem cells was proven to induce neural regeneration in animal mo...Spinal cord injury(SCI)often results in an inhibitory environment at the injury site.In our previous studies,transplantation of a scaffold combined with stem cells was proven to induce neural regeneration in animal models of complete SCI.Based on these preclinical studies,collagen scaffolds loaded with the patients’own bone marrow mononuclear cells or human umbilical cord mesenchymal stem cells were transplanted into SCI patients.Fifteen patients with acute complete SCI and 51 patients with chronic complete SCI were enrolled and followed up for 2 to 5 years.No serious adverse events related to functional scaffold transplantation were observed.Among the patients with acute SCI,five patients achieved expansion of their sensory positions and six patients recovered sensation in the bowel or bladder.Additionally,four patients regained voluntary walking ability accompanied by reconnection of neural signal transduction.Among patients with chronic SCI,16 patients achieved expansion of their sensation level and 30 patients experienced enhanced reflexive defecation sensation or increased skin sweating below the injury site.Nearly half of the patients with chronic cervical SCI developed enhanced finger activity.These long-term follow-up results suggest that functional scaffold transplantation may represent a feasible treatment for patients with complete SCI.展开更多
Spinal cord injury(SCI), especially complete transected SCI, leads to loss of cells and extracellular matrix and functional impairments. In a previous study, we transplanted adult spinal cord tissues(aSCTs) to replace...Spinal cord injury(SCI), especially complete transected SCI, leads to loss of cells and extracellular matrix and functional impairments. In a previous study, we transplanted adult spinal cord tissues(aSCTs) to replace lost tissues and facilitate recovery in a rat SCI model. However, rodents display considerable differences from human patients in the scale, anatomy and functions of spinal cord systems, and responses after injury. Thus, use of a large animal SCI model is required to examine the repair efficiency of potential therapeutic approaches. In this study, we transplanted allogenic aSCTs from adult dogs to the lesion area of canines after complete transection of the thoracic spinal cord, and investigated the long-term cell survival and functional recovery. To enhance repair efficiency, a growth factor cocktail was added during aSCT transplantation, providing a favorable microenvironment. The results showed that transplantation of a SCTs, in particular with the addition of growth factors, significantly improves locomotor function restoration and increases the number of neurofilament-, microtubule-associated protein2-, 5-hydroxytryptamine-, choline acetyltransferase-and tyrosine hydroxylase-positive neurons in the lesion area at 6 months post-surgery. In addition, we demonstrated that donor neurons in a SCTs can survive for a long period after transplantation. This study showed for the first time that transplanting aSCTs combined with growth factor supplementation facilitates reconstruction of injured spinal cords, and consequently promotes long lasting motor function recovery in a large animal complete transected SCI model, and therefore could be considered as a possible therapeutic strategy in humans.展开更多
Nestin is expressed extensively in neural stem/progenitor cells during neural development, but its expression is mainly restricted to the ependymal cells in the adult spinal cord. After spinal cord injury(SCI), Nestin...Nestin is expressed extensively in neural stem/progenitor cells during neural development, but its expression is mainly restricted to the ependymal cells in the adult spinal cord. After spinal cord injury(SCI), Nestin expression is reactivated and Nestinpositive(Nestin;) cells aggregate at the injury site. However, the derivation of Nestin;cells is not clearly defined. Here, we found that Nestin expression was substantially increased in the lesion edge and lesion core after SCI. Using a tamoxifen inducible CreER(T2)-loxP system, we verified that ependymal cells contribute few Nestin;cells either to the lesion core or the lesion edge after SCI. In the lesion edge, GFAP+astrocytes were the main cell type that expressed Nestin;they then formed an astrocyte scar.In the lesion core, Nestin;cells expressed αSMA or Desmin, indicating that they might be derived from pericytes. Our results reveal that Nestin;cells in the lesion core and edge came from various cell types and rarely from ependymal cells after complete transected SCI, which may provide new insights into SCI repair.展开更多
Neural stem cells(NSCs)in the spinal cord hold great potential for repair after spinal cord injury(SCI).The ependyma in the central canal(CC)region has been considered as the NSCs source in the spinal cord.However,the...Neural stem cells(NSCs)in the spinal cord hold great potential for repair after spinal cord injury(SCI).The ependyma in the central canal(CC)region has been considered as the NSCs source in the spinal cord.However,the ependyma function as NSCs after SCI is still under debate.We used Nestin as a marker to isolate potential NSCs and their immediate progeny,and characterized the cells before and after SCI by single-cell RNA-sequencing(scRNA-seq).We identified two subgroups of NSCs:the subgroup located within the CC cannot prime to active NSCs after SCI,while the subgroup located outside the CC were activated and exhibited the active NSCs properties after SCI.We demonstrated the comprehensive dynamic transcriptome of NSCs from quiescent to active NSCs after SCI.This study reveals that Nestin+cells outside CC were NSCs that activated upon SCI and may thus serve as endogenous NSCs for regenerative treatment of SCI in the future.展开更多
OCT4 and NANOG are two important tran-scription factors for maintaining the pluripotency and self-renewal abilities of embryonic stem(ES)cells.Meanwhile they play key roles in the induced pluripotent stem(iPS)cells.In...OCT4 and NANOG are two important tran-scription factors for maintaining the pluripotency and self-renewal abilities of embryonic stem(ES)cells.Meanwhile they play key roles in the induced pluripotent stem(iPS)cells.In this study,recombinant transcript factors TAT-NANOG and TAT-OCT4,which contained a fused powerful protein transduction domain(PTD)TAT from human immunodeficiency virus(HIV),were produced.Each fusion protein could be transported into human adultfibroblasts(HAF)successfully and activated the endogen-ous transcription of both nanog and oct4.Our study revealed the inter-regulation and autoregulation abilities of solo oct4 or nanog in the process of iPS cell reprogram-ming.Meanwhile the transduction of TAT-NANOG could accelerate the growth rate of HAF cells,and the key cell cycle regulator cdc25a was up-regulated.Thus cdc25a may be involved in the regulation of cell growth by NANOG.In addition,the TAT fusion protein technology provided a novel way to improve cell growth that is more controllable and safer.展开更多
基金This work was supported by the National Natural Science Foundation of China Project Nos.[31771817,31801381]National Key Research and Development Program[2019YFD1002603-1].
文摘Soybean oleic acid content is one of the important indexes to evaluate the quality of soybean oil.In the synthesis pathway of soybean fatty acids,the FAD2 gene family is the key gene that regulates the production of linoleic acid from soybean oleic acid.In this study,CRISPR/Cas9 gene editing technology was used to regulate FAD2 gene expression.Firstly,the CRISPR/Cas9 single knockout vectors GmFAD2-1B and GmFAD2-2C and double knockout vectors GmFAD2-2A-3 were constructed.Then,the three vectors were transferred into the recipient soybean variety Jinong 38 by Agrobacterium-mediated cotyledon node transformation,and the mutant plants were obtained.Functional analysis and comparison of the mutant plants of the T2 and T3 generations were carried out.The results showed that there was no significant difference in agronomic traits between the CRISPR/Cas9 single and double knockout vectors and the untransformed CRISPR/Cas9 receptor varieties.The oleic acid content of the plants that knocked out the CRISPR/Cas9 double gene vector was significantly higher than that of the single gene vector.
文摘Recent advances have witnessed the success and popularity of cloud computing, which represents a new business model and computing paradigm. The feature of on-demand provisioning of computational, storage, and bandwidth resources has driven modern businesses into cloud services. The cloud is considered cutting edge technology and it is solely relied on by many large technology, business, and media companies such as Netflix or Salesforce.com. However, in addition to the benefit at hand, security issues have been a long-term concern for cloud computing and are the main barriers of the widespread use of cloud computing. In this paper, we briefly describe some basic security concerns that are of particular interest to cloud technology. We investigate some of the basic cloud concepts and discuss cloud security issues. Amazon Web Services is used as a case study for discussing common cloud terminology. Data security, as well as some cloud specific attacks is introduced. The current state and the future progression of cloud computing is discussed.
基金supported by the Fujian Province Natural Science Foundation (2023J01294)the Natural Science Basic Research Program of Shaanxi (2023-JC-YB-088)+1 种基金the National Natural Science Foundation of China (21501133, 22371067)the China Hunan Provincial Science&Technology Department (2020RC3020, 2021JJ20021,2023JJ40119)。
文摘Dye molecules often change colors(so-called “chromism”) according to the environment variation. However, they are rarely induced by a catalytic amount of cavity. Through encapsulation in the cavity of a porous coordination cage(PCC-2), Rhodamine B(1) is transformed from red quinonoid form(1q) into colorless lactone form(1l) in aprotic polar solutions. The μ4-OH groups in the cavity of PCC-2 are shown to stabilize the uncommon zwitterion intermediate(1z), followed by converting to 1l, thus accelerating the equilibrium. The chromism is catalyzed by 0.25 mol% of PCC-2, and the reaction rate is improved by 80,400times. 1@PCC-2 can be further fabricated to a sol-gel that exhibits ion recognition properties. The resulting encapsulation and stabilization of an unconventional intermediate by a catalytic amount of the coordination cage provides fundamental insights into molecular isomerization and has potential use in chemical sensing.
基金supported by grants from the National Natural Science Foundation of China(No.81891002)the Strategic Priority Research Program of the Chinese Academy of Sciences(,XDA16040702 XDA16040704)+2 种基金Youth Innovation Promotion Association CAS(Grant No.Y202031)We also thanked the support from CAS Project for Young Scientists in Basic Research(Grant No.YSBR073)the Key Research and Development Program of Hunan Province(2021DK2003).
文摘Transplanting human neural progenitor cells is a promising method of replenishing the lost neurons after spinal cord injury (SCI), but differentiating neural progenitor cells into the diverse types of mature functional spinal cord neurons in vivo is challenging. In this study, engineered human embryonic spinal cord-like tissues with dorsal and ventral neuronal characters (DV-SC) were generated by inducing human neural progenitor cells (hscNPCs) to differentiate into various types of dorsal and ventral neuronal cells on collagen scaffold in vitro. Transplantation of DV-SC into complete SCI models in rats and monkeys showed better therapeutic effects than undifferentiated hscNPCs, including pronounced cell survival and maturation. DV-SC formed a targeted connection with the host’s ascending and descending axons, partially restored interrupted neural circuits, and improved motor evoked potentials and the hindlimb function of animals with SCI. This suggests that the transplantation of pre-differentiated hscNPCs with spinal cord dorsal and ventral neuronal characteristics could be a promising strategy for SCI repair.
基金This work was supported by grants from the National Natural Science Foundation of China(No.81891002,No.32071338)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA16040702,XDA16040704)+1 种基金National Key R&D Program of China(2017YFA0104701,2017YFA0104704)CAS Project for Young Scientists in Basic Research(YSRB073).
文摘Neural stem progenitor cell(NSPC)transplantation has been regarded as a promising therapeutic method for spinal cord injury(SCI)repair.However,different NSPCs may have different therapeutic effects,and it is therefore important to identify the optimal NSPC type.In our study,we compared the transcriptomes of human fetal brain-derived NSPCs(BNSPCs),spinal cord-derived NSPCs(SCNSPCs)and H9 embryonic stem-cell derived NSPCs(H9-NSPCs)in vitro and subsequently we transplanted each NSPC type on a collagen scaffold into a T8-9 complete SCI rat model in vivo.In vitro data showed that SCNSPCs had more highly expressed genes involved in nerve-related functions than the other two cell types.In vivo,compared with BNSPCs and H9-NSPCs,SCNSPCs exhibited the best therapeutic effects;in fact,SCNSPCs facilitated electrophysiological and hindlimb functional recovery.This study demonstrates that SCNSPCs may be an appropriate candidate cell type for SCI repair,which is of great clinical significance.
基金supported by grants from the "Stem Cell and Regenerative Medicine Strategic Priority Research Program of the Chinese Academy of Sciences" (Grant No. XDA01030000)the Key Research Program of the Chinese Academy of Sciences (Grant No. ZDRW-ZS-2016-2)
文摘The objective of this clinical study was to assess the safety and feasibility of the collagen scaffold, Neuro Regen scaffold, one year after scar tissue resection and implantation. Scar tissue is a physical and chemical barrier that prevents neural regeneration. However, identification of scar tissue is still a major challenge. In this study, the nerve electrophysiology method was used to distinguish scar tissue from normal neural tissue, and then different lengths of scars ranging from 0.5–4.5 cm were surgically resected in five complete chronic spinal cord injury(SCI) patients. The NeuroR egen scaffold along with autologous bone marrow mononuclear cells(BMMCs), which have been proven to promote neural regeneration and SCI recovery in animal models, were transplanted into the gap in the spinal cord following scar tissue resection. No obvious adverse effects related to scar resection or Neuro Regen scaffold transplantation were observed immediately after surgery or at the 12-month follow-up. In addition, patients showed partially autonomic nervous function improvement, and the recovery of somatosensory evoked potentials(SSEP) from the lower limbs was also detected. The results indicate that scar resection and Neuro Regen scaffold transplantation could be a promising clinical approach to treating SCI.
基金supported by Beijing Natural Science Foundation,China(No.4182020)Open Fund of State Laboratory of Information Engineering in Surveying,Mapping and Remote Sensing,Wuhan University,China(No.17E01)Key Laboratory for Health Monitoring and Control of Large Structures,Shijiazhuang,China(No.KLLSHMC1901)。
文摘A method of multi-block Single Shot Multi Box Detector(SSD)based on small object detection is proposed to the railway scene of unmanned aerial vehicle surveillance.To address the limitation of small object detection,a multi-block SSD mechanism,which consists of three steps,is designed.First,the original input images are segmented into several overlapped patches.Second,each patch is separately fed into an SSD to detect the objects.Third,the patches are merged together through two stages.In the first stage,the truncated object of the sub-layer detection result is spliced.In the second stage,a sub-layer suppression and filtering algorithm applying the concept of non-maximum suppression is utilized to remove the overlapped boxes of sub-layers.The boxes that are not detected in the main-layer are retained.In addition,no sufficient labeled training samples of railway circumstance are available,thereby hindering the deployment of SSD.A two-stage training strategy leveraging to transfer learning is adopted to solve this issue.The deep learning model is preliminarily trained using labeled data of numerous auxiliaries,and then it is refined using only a few samples of railway scene.A railway spot in China,which is easily damaged by landslides,is investigated as a case study.Experimental results show that the proposed multi-block SSD method produces an overall accuracy of 96.6%and obtains an improvement of up to 9.2%compared with the traditional SSD.
基金supported by the "Strategic Priority Research Program of the Chinese Academy of Sciences" (XDA01030000)the key Research Program of the Chinese Academy of Sciences (ZDRW-ZS-2016-2)+3 种基金the National Natural Science Foundation of China (81572131, 81571213)the Natural Science Foundation of Jiangsu Province (BL2012004, BK20151210)the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe key Research and Development Program of Ministry of Science and Technology (2016YFC1101500)
文摘Traumatic spinal cord injury(SCI) is a major challenge in the clinic. In this study, we sought to examine the synergistic effects of linear ordered collagen scaffold(LOCS) and human placenta-derived mesenchymal stem cells(hPMSCs) when transplanted into completely transected beagle dogs. After 36 weeks observation, we found that LOCS+hPMSCs implants promoted better hindlimb locomotor recovery than was observed in the non-treatment(control) group and LOCS group. Histological analysis showed that the regenerated tissue after treatment was well integrated with the host tissue, and dramatically reduced the volume of cystic and chondroitin sulfate proteoglycans(CSPGs) expression. Furthermore, the LOCS+hPMSCs group also showed more neuron-specific βIII-tubulin(Tuj-1)-and NeuN-positive neurons in the lesion area, as well as axonal regeneration, remyelination and synapse formation in the lesion site. Additionally, dogs in the LOCS+hPMSCs group experienced enhanced sprouting of both ascending(CGRP-positive) sensory fibers and descending(5-HT-and TH-positive) motor fibers at the lesion area. All these data together suggested that the combined treatment had beneficial effects on neuronal regeneration and functional improvement in a canine complete transection model. Therefore, LOCS+hPMSCs implantation holds a great promise for bridging the nerve defect and may be clinically useful in the near future.
基金supported by the key Research Program of the Chinese Academy of Sciences (ZDRW-ZS-2016-2)the"Strategic Priority Research Program of the Chinese Academy of Sciences"(XDA01030000)
文摘Traumatic spinal cord injury (SCI) usually results in devastating neurologic deficits and disability. In the United States,approximately 12,500 new cases are reported each year, while an estimated 100,000–140,000 new cases occur every year in China (National Spinal Cord Injury Statistical Center, 2016).Spinal cord injuries are highly disabling and primarily affect young adults, and therefore create great psychological and financial burden on the affected individuals and their families.
基金supported by grants from the National Natural Science Foundation of China (81891002)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA16020100)
文摘Grafted embryonic central neural tissue pieces can recover function of hemisected spinal cord in neonatal rats and promote axonal growth in adults. However, spinal cord segments from adults have not been used as donor segments for allogeneic transplantation. Here, we utilized adult spinal cord tissue grafts(aSCGs) as donor constructs for repairing complete spinal cord injury(SCI). Moreover, to provide a favourable microenvironment for SCI treatment, a growth factor cocktail containing three growth factors(brain-derived neurotrophic factor, neurotrophin-3 and vascular endothelial growth factor), was applied to the aSCG transplants. We found that the locomotor function was significantly improved 12 weeks after transplantation of aSCGs into the spinal cord lesion site in adult rats. Transplantation of aSCGs combined with these growth factors enhanced neuron and oligodendrocyte survival and functional restoration. These encouraging results indicate that treatment of complete SCI by transplanting aSCGs, especially in the presence of growth factors, has a positive effect on motor functional recovery, and therefore could be considered as a possible therapeutic strategy for SCI.
基金supported by the grants from the Ministry of Science and Technology of China(Nos.2011CB965001 and 2011CB710905)the Knowledge Innovation Program of the Chinese Academy of Sciences(Nos.KSCX2-YW-R-232, KJCX2-YW-L08 and KYQY-QN-015)
文摘Mesenchymal stem cells (MSCs) show the great promise for the treatment of a variety of diseases because of their self-renewal and multipotential abilities. MSCs are generally cultured on two-dimensional (2D) substrate in vitro. There are indications that they may simultaneously lose their sternness and multipotentiality as the result of prolonged 2D culture. In this study, we used three-dimensional (3D) collagen scaffolds as rat MSCs cartier and compared the properties of MSCs on 3D collagen scaffolds with monolayer cultured MSCs. The results demonstrated that collagen scaffolds were suitable for rat MSCs adherence and proliferation. More importantly, compared to MSCs under 2D culture, 3D MSCs significantly maintained higher expression levels of stemness genes (Oct4, Sox2, Rex-1 and Nanog), yielded high frequencies of colony-forming units-fibroblastic (CFU-F) and showed enhanced osteogenic and adipogenic differentiation efficiency upon induction. Thus, 3D collagen scaffolds may be beneficial for expanding rat MSCs while maintaining the stem cell properties in vitro.
基金supported by the National Basic Research Program of China (973 Program) (No 2006CB943601)the National Natural Science Foundation of China (NSFC) (No 90919042)
文摘OCT4 is one of the key transcription factors in maintaining the pluripotency and self-renewal of embryonic stem (ES) cells.Human OCT4 can generate two isoforms OCT4A and OCT4B by alternative splicing.OCT4B1 is a recently discovered novel OCT4 spliced variant,which has been considered as a putative marker of stemness.Compared with the OCT4B mRNA,OCT4B1 mRNA is generated by retaining intron 2 as a cryptic exon which contains a TGA stop codon in it.As a result,the protein product of OCT4B1 mRNA could be truncated.Interestingly,we present here that OCT4B1 can indirectly produce the same protein products as OCT4B.We have demonstrated that OCT4B1 mRNA can be spliced into OCT4B mRNA,and encode three protein isoforms.The splicing of OCT4B1 mRNA into OCT4B mRNA can be remarkably inhibited by the mutation of the classical splicing site.Our result suggests that OCT4B mRNA may originate from OCT4B1 mRNA by alternative splicing.
基金supported by grants from the National Natural Science Foundation of China(81891000)the National Key Research and Development Program of China(2016YFC1101504 and2016YFC1101505)。
文摘Spinal cord injury(SCI)often results in an inhibitory environment at the injury site.In our previous studies,transplantation of a scaffold combined with stem cells was proven to induce neural regeneration in animal models of complete SCI.Based on these preclinical studies,collagen scaffolds loaded with the patients’own bone marrow mononuclear cells or human umbilical cord mesenchymal stem cells were transplanted into SCI patients.Fifteen patients with acute complete SCI and 51 patients with chronic complete SCI were enrolled and followed up for 2 to 5 years.No serious adverse events related to functional scaffold transplantation were observed.Among the patients with acute SCI,five patients achieved expansion of their sensory positions and six patients recovered sensation in the bowel or bladder.Additionally,four patients regained voluntary walking ability accompanied by reconnection of neural signal transduction.Among patients with chronic SCI,16 patients achieved expansion of their sensation level and 30 patients experienced enhanced reflexive defecation sensation or increased skin sweating below the injury site.Nearly half of the patients with chronic cervical SCI developed enhanced finger activity.These long-term follow-up results suggest that functional scaffold transplantation may represent a feasible treatment for patients with complete SCI.
基金supported by the National Natural Science Foundation of China(81891002 and 81971178)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA16040700)the National Key Research and Development Program of China(2017YFA0104701,2017YFA0104704,2016YFC1101501 and 2016YFC1101502)。
文摘Spinal cord injury(SCI), especially complete transected SCI, leads to loss of cells and extracellular matrix and functional impairments. In a previous study, we transplanted adult spinal cord tissues(aSCTs) to replace lost tissues and facilitate recovery in a rat SCI model. However, rodents display considerable differences from human patients in the scale, anatomy and functions of spinal cord systems, and responses after injury. Thus, use of a large animal SCI model is required to examine the repair efficiency of potential therapeutic approaches. In this study, we transplanted allogenic aSCTs from adult dogs to the lesion area of canines after complete transection of the thoracic spinal cord, and investigated the long-term cell survival and functional recovery. To enhance repair efficiency, a growth factor cocktail was added during aSCT transplantation, providing a favorable microenvironment. The results showed that transplantation of a SCTs, in particular with the addition of growth factors, significantly improves locomotor function restoration and increases the number of neurofilament-, microtubule-associated protein2-, 5-hydroxytryptamine-, choline acetyltransferase-and tyrosine hydroxylase-positive neurons in the lesion area at 6 months post-surgery. In addition, we demonstrated that donor neurons in a SCTs can survive for a long period after transplantation. This study showed for the first time that transplanting aSCTs combined with growth factor supplementation facilitates reconstruction of injured spinal cords, and consequently promotes long lasting motor function recovery in a large animal complete transected SCI model, and therefore could be considered as a possible therapeutic strategy in humans.
基金supported by grants from the National Natural Science Foundation of China (81891000)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA16040700)+1 种基金the National Key R&D Program of China (2017YFA0104701, 2017YFA0104704 and 2016YFC1101501)the Jiangsu Key R&D Program (BE2018664)
文摘Nestin is expressed extensively in neural stem/progenitor cells during neural development, but its expression is mainly restricted to the ependymal cells in the adult spinal cord. After spinal cord injury(SCI), Nestin expression is reactivated and Nestinpositive(Nestin;) cells aggregate at the injury site. However, the derivation of Nestin;cells is not clearly defined. Here, we found that Nestin expression was substantially increased in the lesion edge and lesion core after SCI. Using a tamoxifen inducible CreER(T2)-loxP system, we verified that ependymal cells contribute few Nestin;cells either to the lesion core or the lesion edge after SCI. In the lesion edge, GFAP+astrocytes were the main cell type that expressed Nestin;they then formed an astrocyte scar.In the lesion core, Nestin;cells expressed αSMA or Desmin, indicating that they might be derived from pericytes. Our results reveal that Nestin;cells in the lesion core and edge came from various cell types and rarely from ependymal cells after complete transected SCI, which may provide new insights into SCI repair.
基金the National Natural Science Foundation of China(81891002 and 81891001)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA16040700)+1 种基金the National Key Research and Development Program of China(2017YFA0104701,2017YFA0104704 and 2016YFC1101501)Jiangsu Key Research and Development Program(BE2018664).
文摘Neural stem cells(NSCs)in the spinal cord hold great potential for repair after spinal cord injury(SCI).The ependyma in the central canal(CC)region has been considered as the NSCs source in the spinal cord.However,the ependyma function as NSCs after SCI is still under debate.We used Nestin as a marker to isolate potential NSCs and their immediate progeny,and characterized the cells before and after SCI by single-cell RNA-sequencing(scRNA-seq).We identified two subgroups of NSCs:the subgroup located within the CC cannot prime to active NSCs after SCI,while the subgroup located outside the CC were activated and exhibited the active NSCs properties after SCI.We demonstrated the comprehensive dynamic transcriptome of NSCs from quiescent to active NSCs after SCI.This study reveals that Nestin+cells outside CC were NSCs that activated upon SCI and may thus serve as endogenous NSCs for regenerative treatment of SCI in the future.
基金supported by grants from the Ministry of Science and Technology of China(No.2006CB943601)the Natural Science Foundation of China(Grant No.90919042).
文摘OCT4 and NANOG are two important tran-scription factors for maintaining the pluripotency and self-renewal abilities of embryonic stem(ES)cells.Meanwhile they play key roles in the induced pluripotent stem(iPS)cells.In this study,recombinant transcript factors TAT-NANOG and TAT-OCT4,which contained a fused powerful protein transduction domain(PTD)TAT from human immunodeficiency virus(HIV),were produced.Each fusion protein could be transported into human adultfibroblasts(HAF)successfully and activated the endogen-ous transcription of both nanog and oct4.Our study revealed the inter-regulation and autoregulation abilities of solo oct4 or nanog in the process of iPS cell reprogram-ming.Meanwhile the transduction of TAT-NANOG could accelerate the growth rate of HAF cells,and the key cell cycle regulator cdc25a was up-regulated.Thus cdc25a may be involved in the regulation of cell growth by NANOG.In addition,the TAT fusion protein technology provided a novel way to improve cell growth that is more controllable and safer.