Spinal cord injury is a challenge in orthopedics because it causes irreversible damage to the central nervous system.Therefore,early treatment to prevent lesion expansion is crucial for the management of patients with...Spinal cord injury is a challenge in orthopedics because it causes irreversible damage to the central nervous system.Therefore,early treatment to prevent lesion expansion is crucial for the management of patients with spinal cord injury.Bexarotene,a type of retinoid,exerts therapeutic effects on patients with cutaneous T-cell lymphoma and Parkinson's disease.Bexarotene has been proven to promote autophagy,but it has not been used in the treatment of spinal cord injury.To investigate the effects of bexarotene on spinal cord injury,we established a mouse model of T11–T12 spinal cord contusion and performed daily intraperitoneal injection of bexarotene for 5 consecutive days.We found that bexarotene effectively reduced the deposition of collagen and the number of pathological neurons in the injured spinal cord,increased the number of synapses of nerve cells,reduced oxidative stress,inhibited pyroptosis,promoted the recovery of motor function,and reduced death.Inhibition of autophagy with 3-methyladenine reversed the effects of bexarotene on spinal cord injury.Bexarotene enhanced the nuclear translocation of transcription factor E3,which further activated AMP-activated protein kinase-S-phase kinase-associated protein 2-coactivator-associated arginine methyltransferase 1 and AMP-activated protein kinase-mammalian target of rapamycin signaling pathways.Intravenous injection of transcription factor E3 sh RNA or intraperitoneal injection of compound C,an AMP-activated protein kinase blocker,inhibited the effects of bexarotene.These findings suggest that bexarotene regulates nuclear translocation of transcription factor E3 through the AMP-activated protein kinase-Sphase kinase-associated protein 2-coactivator-associated arginine methyltransferase 1 and AMP-activated protein kinase-mammalian target of rapamycin signal pathways,promotes autophagy,decreases reactive oxygen species level,inhibits pyroptosis,and improves motor function after spinal cord injury.展开更多
Background:Ensuring the survival of the distal end of a random flap during hypoperfusion(ischaemia)is difficult in clinical practice.Effective prevention of programmed cell death is a potential strategy for inhibiting...Background:Ensuring the survival of the distal end of a random flap during hypoperfusion(ischaemia)is difficult in clinical practice.Effective prevention of programmed cell death is a potential strategy for inhibiting ischaemic flap necrosis.The activation of stimulator of interferon genes(STING)pathway promotes inflammation and leads to cell death.The epidermal growth factor family member neuregulin-1(NRG1)reduces cell death by activating the protein kinase B(AKT)signalling pathway.Moreover,AKT signalling negatively regulates STING activity.We aimed to verify the efficacy of NRG1 injection in protecting against flap necrosis.Additionally,we investigated whether NRG1 effectively enhances ischemic flap survival by inhibiting pyroptosis and necroptosis through STING suppression.Methods:A random-pattern skin flap model was generated on the backs of C57BL/6 mice.The skin flap survival area was determined.The blood supply and vascular network of the flap was assessed by laser Doppler blood flow analysis.Cluster of differentiation 34 immunohistochemistry(IHC)and haematoxylin and eosin(H&E)staining of the flap sections revealed microvessels.Transcriptome sequencing analysis revealed the mechanism by which NRG1 promotes the survival of ischaemic flaps.The levels of angiogenesis,oxidative stress,necroptosis,pyroptosis and indicators associated with signalling pathways in flaps were examined by IHC,immunofluorescence and Western blotting.Packaging adenoassociated virus(AAV)was used to activate STING in flaps.Results:NRG1 promoted the survival of ischaemic flaps.An increased subcutaneous vascular network and neovascularization were found in ischaemic flaps after the application of NRG1.Transcriptomic gene ontology enrichment analysis and protein level detection indicated that necroptosis,pyroptosis and STING activity were reduced in the NRG1 group.The phosphorylation of AKT and forkhead box O3a(FOXO3a)were increased after NRG1 treatment.The increased expression of STING in flaps induced by AAV reversed the therapeutic effect of NRG1.The ability of NRG1 to phosphorylate AKT-FOXO3a,inhibit STING and promote flap survival was abolished after the application of the AKT inhibitor MK2206.Conclusions:NRG1 inhibits pyroptosis and necroptosis by activating the AKT-FOXO3a signalling pathway to suppress STING activation and promote ischaemic flap survival.展开更多
基金grants from Zhejiang Provincial Medicine and Health Technology Project,No.2021KY214(to SS)Zhejiang Provincial Science and Technology Project of Traditional Chinese Medicine,No.2021ZB183(to HX)。
文摘Spinal cord injury is a challenge in orthopedics because it causes irreversible damage to the central nervous system.Therefore,early treatment to prevent lesion expansion is crucial for the management of patients with spinal cord injury.Bexarotene,a type of retinoid,exerts therapeutic effects on patients with cutaneous T-cell lymphoma and Parkinson's disease.Bexarotene has been proven to promote autophagy,but it has not been used in the treatment of spinal cord injury.To investigate the effects of bexarotene on spinal cord injury,we established a mouse model of T11–T12 spinal cord contusion and performed daily intraperitoneal injection of bexarotene for 5 consecutive days.We found that bexarotene effectively reduced the deposition of collagen and the number of pathological neurons in the injured spinal cord,increased the number of synapses of nerve cells,reduced oxidative stress,inhibited pyroptosis,promoted the recovery of motor function,and reduced death.Inhibition of autophagy with 3-methyladenine reversed the effects of bexarotene on spinal cord injury.Bexarotene enhanced the nuclear translocation of transcription factor E3,which further activated AMP-activated protein kinase-S-phase kinase-associated protein 2-coactivator-associated arginine methyltransferase 1 and AMP-activated protein kinase-mammalian target of rapamycin signaling pathways.Intravenous injection of transcription factor E3 sh RNA or intraperitoneal injection of compound C,an AMP-activated protein kinase blocker,inhibited the effects of bexarotene.These findings suggest that bexarotene regulates nuclear translocation of transcription factor E3 through the AMP-activated protein kinase-Sphase kinase-associated protein 2-coactivator-associated arginine methyltransferase 1 and AMP-activated protein kinase-mammalian target of rapamycin signal pathways,promotes autophagy,decreases reactive oxygen species level,inhibits pyroptosis,and improves motor function after spinal cord injury.
基金supported by the Natural Science Foundation of China[82372540,82072192,81801930,81873942]Wenzhou Science and Technology Bureau Foundation[Y20210438,Y2023475]+3 种基金Public Welfare Technology Research Project of Zhejiang Province[LGF20H150003LQ23H090006]Basic Public Welfare Research Project of Zhejiang Province[No.LY19H060003]Medical Health Science and Technology Project of Zhejiang Province[No.2020KY183].
文摘Background:Ensuring the survival of the distal end of a random flap during hypoperfusion(ischaemia)is difficult in clinical practice.Effective prevention of programmed cell death is a potential strategy for inhibiting ischaemic flap necrosis.The activation of stimulator of interferon genes(STING)pathway promotes inflammation and leads to cell death.The epidermal growth factor family member neuregulin-1(NRG1)reduces cell death by activating the protein kinase B(AKT)signalling pathway.Moreover,AKT signalling negatively regulates STING activity.We aimed to verify the efficacy of NRG1 injection in protecting against flap necrosis.Additionally,we investigated whether NRG1 effectively enhances ischemic flap survival by inhibiting pyroptosis and necroptosis through STING suppression.Methods:A random-pattern skin flap model was generated on the backs of C57BL/6 mice.The skin flap survival area was determined.The blood supply and vascular network of the flap was assessed by laser Doppler blood flow analysis.Cluster of differentiation 34 immunohistochemistry(IHC)and haematoxylin and eosin(H&E)staining of the flap sections revealed microvessels.Transcriptome sequencing analysis revealed the mechanism by which NRG1 promotes the survival of ischaemic flaps.The levels of angiogenesis,oxidative stress,necroptosis,pyroptosis and indicators associated with signalling pathways in flaps were examined by IHC,immunofluorescence and Western blotting.Packaging adenoassociated virus(AAV)was used to activate STING in flaps.Results:NRG1 promoted the survival of ischaemic flaps.An increased subcutaneous vascular network and neovascularization were found in ischaemic flaps after the application of NRG1.Transcriptomic gene ontology enrichment analysis and protein level detection indicated that necroptosis,pyroptosis and STING activity were reduced in the NRG1 group.The phosphorylation of AKT and forkhead box O3a(FOXO3a)were increased after NRG1 treatment.The increased expression of STING in flaps induced by AAV reversed the therapeutic effect of NRG1.The ability of NRG1 to phosphorylate AKT-FOXO3a,inhibit STING and promote flap survival was abolished after the application of the AKT inhibitor MK2206.Conclusions:NRG1 inhibits pyroptosis and necroptosis by activating the AKT-FOXO3a signalling pathway to suppress STING activation and promote ischaemic flap survival.
