Spinal cord injuries have overwhelming physical and occupational implications for patients.Moreover,the extensive and long-term medical care required for spinal cord injury significantly increases healthcare costs and...Spinal cord injuries have overwhelming physical and occupational implications for patients.Moreover,the extensive and long-term medical care required for spinal cord injury significantly increases healthcare costs and resources,adding a substantial burden to the healthcare system and patients'families.In this context,chondroitinase ABC,a bacterial enzyme isolated from Proteus vulgaris that is modified to facilitate expression and secretion in mammals,has emerged as a promising therapeutic agent.It works by degrading chondroitin sulfate proteoglycans,cleaving the glycosaminoglycanchains of chondroitin sulfate proteoglycans into soluble disaccharides or tetrasaccharides.Chondroitin sulfate proteoglycans are potent axon growth inhibitors and principal constituents of the extracellular matrix surrounding glial and neuronal cells attached to glycosaminoglycan chains.Chondroitinase ABC has been shown to play an effective role in promoting recovery from acute and chronic spinal cord injury by improving axonal regeneration and sprouting,enhancing the plasticity of perineuronal nets,inhibiting neuronal apoptosis,and modulating immune responses in various animal models.In this review,we introduce the classification and pathological mechanisms of spinal cord injury and discuss the pathophysiological role of chondroitin sulfate proteoglycans in spinal cord injury.We also highlight research advancements in spinal cord injury treatment strategies,with a focus on chondroitinase ABC,and illustrate how improvements in chondroitinase ABC stability,enzymatic activity,and delivery methods have enhanced injured spinal cord repair.Furthermore,we emphasize that combination treatment with chondroitinase ABC further enhances therapeutic efficacy.This review aimed to provide a comprehensive understanding of the current trends and future directions of chondroitinase ABC-based spinal cord injury therapies,with an emphasis on how modern technologies are accelerating the optimization of chondroitinase ABC development.展开更多
The barriers present in the interfaces between the blood and the central nervous system form a major hurdle for the pharmacological treatment of central nervous system injuries and diseases.The family of ATP-binding c...The barriers present in the interfaces between the blood and the central nervous system form a major hurdle for the pharmacological treatment of central nervous system injuries and diseases.The family of ATP-binding cassette(ABC)transporters has been widely studied regarding efflux of medications at blood-central nervous system barriers.These efflux transporters include P-glycoprotein(abcb1),‘breast cancer resistance protein'(abcg2)and the various‘multidrug resistance-associated proteins'(abccs).Understanding which efflux transporters are present at the blood-spinal cord,blood-cerebrospinal fluid and cerebrospinal fluid-spinal cord barriers is necessary to determine their involvement in limiting drug transfer from blood to the spinal cord tissue.Recent developments in the blood-brain barrier field have shown that barrier systems are dynamic and the profile of barrier defenses can alter due to conditions such as age,disease and environmental challenge.This means that a true understanding of ABC efflux transporter expression and localization should not be one static value but instead a range that represents the complex patient subpopulations that exist.In the present review,the blood-central nervous system barrier literature is discussed with a focus on the impact of ABC efflux transporters on:(i)protecting the spinal cord from adverse effects of systemically directed drugs,and(ii)limiting centrally directed drugs from accessing their active sites within the spinal cord.展开更多
Schwann cell transplantation is considered one of the most promising cell-based therapy to repair injured spinal cord due to its unique growth-promoting and myelin-forming properties.A the Food and Drug Administration...Schwann cell transplantation is considered one of the most promising cell-based therapy to repair injured spinal cord due to its unique growth-promoting and myelin-forming properties.A the Food and Drug Administration-approved Phase I clinical trial has been conducted to evaluate the safety of transplanted human autologous Schwann cells to treat patients with spinal cord injury.A major challenge for Schwann cell transplantation is that grafted Schwann cells are confined within the lesion cavity,and they do not migrate into the host environment due to the inhibitory barrier formed by injury-induced glial scar,thus limiting axonal reentry into the host spinal cord.Here we introduce a combinatorial strategy by suppressing the inhibitory extracellular environment with injection of lentivirus-mediated transfection of chondroitinase ABC gene at the rostral and caudal borders of the lesion site and simultaneously leveraging the repair capacity of transplanted Schwann cells in adult rats following a mid-thoracic contusive spinal cord injury.We report that when the glial scar was degraded by chondroitinase ABC at the rostral and caudal lesion borders,Schwann cells migrated for considerable distances in both rostral and caudal directions.Such Schwann cell migration led to enhanced axonal regrowth,including the serotonergic and dopaminergic axons originating from supraspinal regions,and promoted recovery of locomotor and urinary bladder functions.Importantly,the Schwann cell survival and axonal regrowth persisted up to 6 months after the injury,even when treatment was delayed for 3 months to mimic chronic spinal cord injury.These findings collectively show promising evidence for a combinatorial strategy with chondroitinase ABC and Schwann cells in promoting remodeling and recovery of function following spinal cord injury.展开更多
Efficient synthetic routs for the direct and rapid construction of[5-6-6]ABC tricyclic systems of daphmanidin A-type and calyciphylline A-type alkaloids have been successfully developed.For the daphmanidin A-type,the ...Efficient synthetic routs for the direct and rapid construction of[5-6-6]ABC tricyclic systems of daphmanidin A-type and calyciphylline A-type alkaloids have been successfully developed.For the daphmanidin A-type,the synthesis of[5-6-6]tricyclic framework utilize a HCl-mediated intramolecular Aldol reaction to construct the bicyclo[2.2.2]octane core and a thermal condensation to afford the ABC ring system.In addition,for the calyciphylline A-type,an improved synthesis of ABC[5-6-6]tricyclic system was developed,featuring an introduction of methyl ester group at C2 before the Pd-catalyzed intramolecular oxidative alkylation to construct the desired bowl-shape tricyclic core with stereochemical control.展开更多
Adenosine triphosphate(ATP)-binding cassette(ABC)transporter systems are divided into importers and exporters that facilitate the movement of diverse substrate molecules across the lipid bilayer,against the concentrat...Adenosine triphosphate(ATP)-binding cassette(ABC)transporter systems are divided into importers and exporters that facilitate the movement of diverse substrate molecules across the lipid bilayer,against the concentration gradient.These transporters comprise two highly conserved nucleotide-binding domains(NBDs)and two transmembrane domains(TMDs).Unlike ABC exporters,prokaryotic ABC importers require an additional substrate-binding protein(SBP)as a recognition site for specific substrate translocation.The discovery of a large number of ABC systems in bacterial pathogens revealed that these transporters are crucial for the establishment of bacterial infections.The existing literature has highlighted the roles of ABC transporters in bacterial growth,pathogenesis,and virulence.These roles include importing essential nutrients required for a variety of cellular processes and exporting outer membrane-associated virulence factors and antimicrobial substances.This review outlines the general structures and classification of ABC systems to provide a comprehensive view of the activities and roles of ABC transporters associated with bacterial virulence and pathogenesis during infection.展开更多
基金supported by the National Natural Science Foundation of China,No.82002645China Postdoctoral Science Foundation,No.2022M722321Jiangsu Funding Program for Excellent Postdoctoral Talent,No.2022ZB552(all to YH)。
文摘Spinal cord injuries have overwhelming physical and occupational implications for patients.Moreover,the extensive and long-term medical care required for spinal cord injury significantly increases healthcare costs and resources,adding a substantial burden to the healthcare system and patients'families.In this context,chondroitinase ABC,a bacterial enzyme isolated from Proteus vulgaris that is modified to facilitate expression and secretion in mammals,has emerged as a promising therapeutic agent.It works by degrading chondroitin sulfate proteoglycans,cleaving the glycosaminoglycanchains of chondroitin sulfate proteoglycans into soluble disaccharides or tetrasaccharides.Chondroitin sulfate proteoglycans are potent axon growth inhibitors and principal constituents of the extracellular matrix surrounding glial and neuronal cells attached to glycosaminoglycan chains.Chondroitinase ABC has been shown to play an effective role in promoting recovery from acute and chronic spinal cord injury by improving axonal regeneration and sprouting,enhancing the plasticity of perineuronal nets,inhibiting neuronal apoptosis,and modulating immune responses in various animal models.In this review,we introduce the classification and pathological mechanisms of spinal cord injury and discuss the pathophysiological role of chondroitin sulfate proteoglycans in spinal cord injury.We also highlight research advancements in spinal cord injury treatment strategies,with a focus on chondroitinase ABC,and illustrate how improvements in chondroitinase ABC stability,enzymatic activity,and delivery methods have enhanced injured spinal cord repair.Furthermore,we emphasize that combination treatment with chondroitinase ABC further enhances therapeutic efficacy.This review aimed to provide a comprehensive understanding of the current trends and future directions of chondroitinase ABC-based spinal cord injury therapies,with an emphasis on how modern technologies are accelerating the optimization of chondroitinase ABC development.
文摘The barriers present in the interfaces between the blood and the central nervous system form a major hurdle for the pharmacological treatment of central nervous system injuries and diseases.The family of ATP-binding cassette(ABC)transporters has been widely studied regarding efflux of medications at blood-central nervous system barriers.These efflux transporters include P-glycoprotein(abcb1),‘breast cancer resistance protein'(abcg2)and the various‘multidrug resistance-associated proteins'(abccs).Understanding which efflux transporters are present at the blood-spinal cord,blood-cerebrospinal fluid and cerebrospinal fluid-spinal cord barriers is necessary to determine their involvement in limiting drug transfer from blood to the spinal cord tissue.Recent developments in the blood-brain barrier field have shown that barrier systems are dynamic and the profile of barrier defenses can alter due to conditions such as age,disease and environmental challenge.This means that a true understanding of ABC efflux transporter expression and localization should not be one static value but instead a range that represents the complex patient subpopulations that exist.In the present review,the blood-central nervous system barrier literature is discussed with a focus on the impact of ABC efflux transporters on:(i)protecting the spinal cord from adverse effects of systemically directed drugs,and(ii)limiting centrally directed drugs from accessing their active sites within the spinal cord.
基金supported in part by NIH R01 NS100531,R01 NS103481NIH R21NS130241(to LD)+3 种基金Merit Review Award I01 BX002356,I01 BX003705 from the U.S.Department of Veterans AffairsIndiana Spinal Cord and Brain Injury Research Foundation(No.19919)Mari Hulman George Endowment Funds(to XMX)Indiana Spinal Cord&Brain Injury Research Fund from ISDH(to NKL and LD)。
文摘Schwann cell transplantation is considered one of the most promising cell-based therapy to repair injured spinal cord due to its unique growth-promoting and myelin-forming properties.A the Food and Drug Administration-approved Phase I clinical trial has been conducted to evaluate the safety of transplanted human autologous Schwann cells to treat patients with spinal cord injury.A major challenge for Schwann cell transplantation is that grafted Schwann cells are confined within the lesion cavity,and they do not migrate into the host environment due to the inhibitory barrier formed by injury-induced glial scar,thus limiting axonal reentry into the host spinal cord.Here we introduce a combinatorial strategy by suppressing the inhibitory extracellular environment with injection of lentivirus-mediated transfection of chondroitinase ABC gene at the rostral and caudal borders of the lesion site and simultaneously leveraging the repair capacity of transplanted Schwann cells in adult rats following a mid-thoracic contusive spinal cord injury.We report that when the glial scar was degraded by chondroitinase ABC at the rostral and caudal lesion borders,Schwann cells migrated for considerable distances in both rostral and caudal directions.Such Schwann cell migration led to enhanced axonal regrowth,including the serotonergic and dopaminergic axons originating from supraspinal regions,and promoted recovery of locomotor and urinary bladder functions.Importantly,the Schwann cell survival and axonal regrowth persisted up to 6 months after the injury,even when treatment was delayed for 3 months to mimic chronic spinal cord injury.These findings collectively show promising evidence for a combinatorial strategy with chondroitinase ABC and Schwann cells in promoting remodeling and recovery of function following spinal cord injury.
基金supported by the National Natural Science Foundation of China(No.21502011)the Fundamental Research Funds for the Central Universitiesthe Chongqing Science&Technology Commission Project(No.cstc2016jcyjA0168)。
文摘Efficient synthetic routs for the direct and rapid construction of[5-6-6]ABC tricyclic systems of daphmanidin A-type and calyciphylline A-type alkaloids have been successfully developed.For the daphmanidin A-type,the synthesis of[5-6-6]tricyclic framework utilize a HCl-mediated intramolecular Aldol reaction to construct the bicyclo[2.2.2]octane core and a thermal condensation to afford the ABC ring system.In addition,for the calyciphylline A-type,an improved synthesis of ABC[5-6-6]tricyclic system was developed,featuring an introduction of methyl ester group at C2 before the Pd-catalyzed intramolecular oxidative alkylation to construct the desired bowl-shape tricyclic core with stereochemical control.
基金supported by the Universiti Kebangsaan Malaysia under the Research University Grant(No.GUP-2020-030)awarded to Sylvia CHIENG.
文摘Adenosine triphosphate(ATP)-binding cassette(ABC)transporter systems are divided into importers and exporters that facilitate the movement of diverse substrate molecules across the lipid bilayer,against the concentration gradient.These transporters comprise two highly conserved nucleotide-binding domains(NBDs)and two transmembrane domains(TMDs).Unlike ABC exporters,prokaryotic ABC importers require an additional substrate-binding protein(SBP)as a recognition site for specific substrate translocation.The discovery of a large number of ABC systems in bacterial pathogens revealed that these transporters are crucial for the establishment of bacterial infections.The existing literature has highlighted the roles of ABC transporters in bacterial growth,pathogenesis,and virulence.These roles include importing essential nutrients required for a variety of cellular processes and exporting outer membrane-associated virulence factors and antimicrobial substances.This review outlines the general structures and classification of ABC systems to provide a comprehensive view of the activities and roles of ABC transporters associated with bacterial virulence and pathogenesis during infection.
